Solution Manual For Discovering Engineering Design in the 21st Century 1st Edition by Bradley Strieb

A SOLUTION AND ANSWER GUIDE TO ACCOMPANY

DISCOVERING ENGINEERING DESIGN IN THE 21ST CENTURY: AN ACTIVITIES-BASED APPROACH FIRST EDITION BRADLEY A. STRIEBIG

ISBN: 978-0-357-68534-1

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SOLUTION AND ANSWER GUIDE TO ACCOMPANY

DISCOVERING ENGINEERING DESIGN IN THE 21ST CENTURY: AN ACTIVITIESBASED APPROACH First Edition

BRADLEY A. STRIEBIG

James Madison University

Contents Chapter 1 ...................................................................................................................................... 1-1 Chapter 2 ...................................................................................................................................... 2-1 Chapter 3 ...................................................................................................................................... 3-1 Chapter 4 ...................................................................................................................................... 4-1 Chapter 5 ...................................................................................................................................... 5-1 Chapter 6 ...................................................................................................................................... 6-1 Chapter 7 ...................................................................................................................................... 7-1 Chapter 8 ...................................................................................................................................... 8-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 1: Engineering Concepts and Simple Tools: Materials, Mass, Gravity, and Moment Arms

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 1: Engineering Concepts and Simple Tools: Materials, Mass, Gravity, and Moment Arms

Chapter 1 Questions

1.1 What are you currently doing, and why?

Solution Answers may vary. Answers may include but are not limited to current work status, current daily habits, or current hobbies followed by an explanation as to why you are engaging in such activity/activities.

Excellent

Good

Answers show thought about what steps a student is taking in their engineering education and thoughtful response to the motivation for those steps

Answers show some thought about what steps a student is taking in their education or the motivation for those steps

Needs Improvement Answers show minimal thought about what steps a student is taking in their education and the motivation for those steps

Poor

Unacceptable

Answers partially address the steps a student is taking in their education and the motivation for those steps

Missing or answers an unrelated question

Poor

Unacceptable

Answers minimally address goals and are unclear

Missing or answers an unrelated question

1.2 What would you like to accomplish before you retire?

Solution Answers may vary.

Excellent

Good

Answers show consideration and clear articulation of long-term goals

Answers show some thought about longterm goals but have difficulty articulating them

Needs Improvement Answers show minimal thought about long-term goals

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1-1

Solution and Answer Guide:

1.3 Describe how the U.S. Bureau of Labor Statistics defines an engineer and an engineering technician (or engineering technologies) by reviewing the “field of degree” highlights for students and job seekers in the Occupational Outlook Handbook. Describe the difference between an engineer and a technician and provide a salary range for each (www.bls.gov/ooh/field-of-degree).

Solution This answer should include the salaries for an engineer (~$95,000 USD-2022) and a technician (~$78,000 USD-2022). This may differ based on which type of engineer is chosen from the Occupational Outlook Handbook. Answers should include the job descriptions of each job and any notable differences. These differences may include the following: job clearance levels, pay scale differences, educational differences, etc.

1.4 The National Society of Professional Engineers (NSPE) has established a Code of Ethics for engineers. Look up and write down the six fundamental canons of the NSPE Code of Ethics.

Solution 1) Hold paramount safety, health, and welfare of the public 2) Perform services only in areas of their competence 3) Issue public statements only in an objective and truthful manner 4) Act for each employer or clients as faithful agents or trustees 5) Avoid deceptive acts 6) Conduct themselves honorably, responsibly, ethically, and lawfully so as to enhance the honor, representation, and usefulness of the profession 1.5 Describe the problems with using an ancient human proportion–based measurement system if you were to build a horse-drawn carriage and you were to purchase parts for the carriage and horses from 12 different suppliers. You are also concerned about navigating under a bridge that is one fathom high that you must pass under to get between your work and your home.

Solution Responses may include the following: The ancient method is outdated due to the form of measurement used. Measurements were based on human portions which can vary from person to person, leading to inconsistent measurements. A horse drawn carriage consists of moving parts that must all simultaneously move together; if each supplier sells parts measured to their own proportions, there could be sizing issues that do not allow the carriage to properly function. If the underpass is sized using unique measurements, it would offer another challenge. In short, if everything is uniquely sized with the proportions of the manufacturers, then there are no uniform universal measurements, making it difficult to produce anything.

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1-2

Solution and Answer Guide:

1.6 Force is a derived quantity determined from the acceleration of an object multiplied by the mass of an object. Derive the dimensions used to create units for a force acting on an object from the fundamental quantities of length, mass, and time. Also, show the SI units of force in your derivation.

Solution Force = mass x acceleration (F = ma) by Newton’s Second Law Acceleration = change in velocity over time A = velocity/time = displacement/(time x time) = L/T x T = L/T2 F = M x L/T2 1.7 The highest mountain in the world is Mount Everest in Nepal. The peak of Mount Everest is 29,029 feet above sea level. How many miles high is this? What is the elevation in meters?

Solution To convert from the height in feet to miles: 29,029 ft ×

1 mile = 5.4979 miles 5,280 ft

To convert from the height in feet to meters: 29,029 ft ×

1m = 8,848.1 m 3.2808 ft

1.8 How many bees would it take to lift the GoPro for a BeeDrone Cam? Solution To determine the number of bees needed: 159 g ×

1 bead

0.012 g

×

1 bee

8 beads

= 1,646 bees are needed to lift the GoPro

1.9 How many bees can fit on top of the GoPro to carry it?

Solution Dimensions of GoPro = 71.8 (L) x 50.8 (W) x 33.6 (H) mm To find out the area of each side it may be useful to draw a picture. Note that the question is how many bees can fit on top.

The top area of the GoPro is: Area (mm2 ) = L × W = 71.8 mm × 50.8 mm = 3,647 mm2

The number of bees that fit on the top is: 3,647 mm2 ×

1 in2

645.2 mm2

×

10 bees in2

= 56.53 = 56 bees can fit on the top of the GoPro

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1-3

Solution and Answer Guide:

1.10 How does the number of bees required compare to the number of bees that would fit on the top of a GoPro? Does your friend’s idea have wings; that is, is the BeeDrone a good idea or not?

Solution There are far more bees needed to lift the GoPro (approximately 1,646 bees) compared to how many can fit on the top of the GoPro. The bee drone is not a good idea because a much larger number of bees are needed to lift the mass of the GoPro than could possibly be attached to the camera.

1.11 Determine the bug weight in kilograms and enter the data from Table 1.4 into a spreadsheet program like Excel or Google Sheets.

Solution The bug weight in kilograms is calculated by dividing by 1000: 0.1 g ×

1 kg

1,000 g

= 0.0001 g

Table 1.4 Deceleration of a theoretical “bug” on impact with an object Bug Weight [g] 0.1 10 60

Bug Weight [kg] 0.0001 0.01 0.06

Deceleration [m/s2] 450,000 17,000 7,500

Force [N]

1.12 Calculate the force in newtons and plot the data from Table 1.4 in the spreadsheet.

Solution Force = mass x acceleration: F = m × a = 0.0001 kg × 450,000 m�s 2 = 45 N

Table 1.4 Deceleration of a theoretical “bug” on impact with an object Bug Weight [g] 0.1 10 60

Bug Weight [kg] 0.0001 0.01 0.06

Deceleration [m/s2] 450,000 17,000 7,500

Force [N] 45 170 450

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1-4

Solution and Answer Guide:

1.13 Graph the data point in an Excel graph with acceleration (y-axis) vs. mass (x-axis). a. Plot the data on a scatterplot. b. Insert a power function trend line. c. Note the equation and R2 value of the trend line on the graph.

Solution The graph for the acceleration vs. mass is shown below. The graph should include labels and units for each axis, the equation of the trend line, and the value for the R2 fit.

1000000 y = 1,026.63x-0.65 R² = 1.00

Acceleration [m/s2]

100000 10000 1000 100 10 1 0.0001

0.001

0.01 Mass [kg]

0.1

1

1.14 Use the trend line equation to calculate the mass of a bug needed to impact exactly the lethal force required by a blow to the larynx (338 N).

Solution The trendline showing the acceleration (y) vs mass (x) relationship can be approximated by: F=mxa The force required is 76 lbf, an English measure of force. There are 4.4482 Newton per lbf.

Flethal = 76 lbf ×

4.4482 N = 338 N lbf

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1-5

Solution and Answer Guide:

Substituting the equation from the graph yields: Flethal = m × 1,026.63 m−0.65 = 338 m0.35 =

338

1,022.63

= 0.0418 kg = 41.8 g

1.15 Determine the force from the impact of a bug in units of newtons for a motorcycle traveling at 40 m/s and a 60-g bug using the previous data to interpolate the required values.

Write the relevant equations. Label your variables. Show your algebraic work and any unit conversations required. Calculate the force associated with each different velocity and complete Table 1.5 using a spreadsheet.

Solution F=mxa F = Force [N] m = mass [kg] a = acceleration [m/s2] F[N] = m[kg] × a �m�s 2 � = 0.06[kg] × −7,500 �m�s 2 � = −450 [N]

Notice that the force is negative, which means the force acts opposite the direction that the motorcycle is traveling.

Table 1.5 High-powered simulated bugs shot out of a cannon to impart lethal force Motorcycle Velocity [m/s] 40 54 90

Bug Weight [kg] 0.06 0.06 0.06

Deceleration [m/s2] (−) 7,500 (−) 21,000 (−) 40,000

Force [N] -450 -1,260 -2,400

1.16 Graph the data point in an Excel graph with acceleration (y-axis) vs. velocity (x-axis). a. Plot the data on a scatterplot. b. Insert a logarithmic function trend line. c. Note the equation and R2 value of the trend line on the graph.

Solution The graph for the acceleration vs. mass is shown below. The graph should include labels and units for each axis, the equation of the trend line, and the value for the R2 fit.

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1-6

Solution and Answer Guide:

1.17 Estimate the force imparted when a 60-g bug impacts an object if the speed differential between the bug and the object is 45 m/s. Use the acceleration by interpolation or from the graphical data. Show your calculations.

Solution F=mxa The trendline shows the acceleration (y) vs velocity (x) relationship. Substituting the equation from the graph yields: F = m × (37,922 {ln(v)} − 160,816)

F = 0.06 × (37,922 {ln(45)} − 160,816) = −9650 N

1.18 Determine the equation that relates the force imparted to a motorcycle driver at various velocities from a curve fit of the graphical data. Use this relationship to determine the speed that a motorcycle would have to be traveling in order to impart a lethal force (338 N) to a motorcyclist from a 10-g cicada.

Solution F=mxa The lethal force required is 76 lbf, an English measure of force. There are 4.4482 Newtons per lbf.

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1-7

Solution and Answer Guide:

Flethal = 76 lbf ×

4.4482 N = 338 N lbf

The trendline shows the acceleration (y) vs velocity (x) relationship. Substituting the equation from the graph yields: F = m × (37,922 {ln(v)} − 160,816) = 338 0.010 × (37,922 {ln(v)} − 160,816) = 338 37,922 {ln(v)} =

338 + 160,816 = 194,616 0.010

{ln(v)} =

194,616 = 5.13 37,922

v = e5.13 = 170 m/s

Note that 170 m/s (380 mph) is just about the land-speed record for the fastest motorcycle, at the time of publication. The record was set by the Ack Attack motorcycle, a specially constructed land-speed record streamliner motorcycle which set the two-way average speed record of 605.697 km/h (376.363 mph) on September 25, 2010 in the Cook Motorsports Top Speed Shootout at Bonneville Speedway, Utah.

1.19 What are the initials of the person who made this drawing?

Solution

JWW 1.20 What are the units of measurement shown on the drawing?

Solution Inches 1.21 What is the scale of the drawing?

Solution 2:1 1.22 What is the length of each side of the square top of this part?

Solution 1 inch 1.23 What is the depth of the side of this part?

Solution 0.25 n

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1-8

Solution and Answer Guide:

1.24 Label one example of the following line types on the drawing shown in Figure 1.7: a. Solid line b. Hidden line c. Dimension line Solution a. Solid line - Answers can include any perimeter lines on the square and rectangle b. Hidden line – Any dashed lines on the drawing c. Dimension line – Any line with a number value and arrows 1.25 Do the following for the aluminum counterbalance shown in Figure 1.7. a. Record the dimensions of the part’s height, width, and depth.

Solution i. ii. iii.

Depth = .25 inch Width = 1 inch Height = 1 inch

b. Calculate the material volume of the part. Remember that you must consider the hole in the part when calculating the volume of the part’s material.

Solution The volume of the circular hole cut out of the part is Vhole = Acircle × H = π

d2 4

The volume of the whole part is

×H = π

0.252 4

× 0.25 = 0.0123 in3

𝑉𝑉𝐴𝐴𝐴𝐴 = 𝑉𝑉𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 − 𝑉𝑉ℎ𝑜𝑜𝑜𝑜𝑜𝑜 = 𝐿𝐿 × 𝑊𝑊 × 𝐻𝐻 − 𝑉𝑉ℎ𝑜𝑜𝑜𝑜𝑜𝑜 c.

VAl = 1 × 1 × 0.25 − 0.0123 = 0.24 in3

If the aluminum has a density of 2.7 g/cm3, what is the mass of the counterbalance part shown in Figure 1.7?

Solution

mAl = VAl × ρAl = 0.24 in3 × �

2.54 cm 3 g � × 2.7 � 3 = 10.6 g cm 1 in

d. If the counterbalance was hung on the end of a nail, what is the force that would be applied on the end of the nail? In which direction does the force applied to the nail act?

Solution Fcounterbalance = m × a gravity = 10.6 g ×

kg × 9.81 m�s 2 = 0.104 N 1,000 g

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1-9

Solution and Answer Guide:

1.26 Do the following given that water has a density of approximately 1,000 kg/m3 and that the PVC from which the pipe and endcap on the attached drawings (Figures 1.10 and 1.11) are made has a density of approximately 1,330 kg/m3. a. Calculate the length of pipe, x, required to contain 56.7 g of water.

Solution

1 kg mwater 56.7 g × 1000 g = = 5.67 × 10−5 m3 Vwater = kg� ρwater 1000 m3

The diameter, D, of the inner area of the circular PVC pipe is shown on Figure 1.10 as 0.80 inches.

The area inside the pipe is found from:

x = Lpipe =

Ainner = π�4 D2 = π�4 �0.80 in ×

0.0254 m 2 � = 3.24 × 10−4 m2 in

Vwater 5.67 × 10−5 m3 in = = 0.175 m = 17.5 cm × = 6 7�8 inches −4 2 Ainner 3.24 × 10 m 2.54 cm

b. Calculate the mass of the pipe in grams.

Solution The volume of the cylinder based on the outer diameter of the PVC pipe: Vouter = Lpipe Aouter = Lpipe × π�4 D2 = 0.17 × π�4 �1.05 in ×

0.0254 m 2 in

Vinner = Vwater = 5.67 × 10−5 m3

� = 9.77 × 10−5 m3

VPVC = Vouter − Vinner = 9.77 × 10−5 m3 − 5.67 × 10−5 m3 = 4.10 × 10−5 m3

mpipe = VPVC × ρPVC = 4.10 × 10−5 m3 × 1330 c.

kg� m3 = 0.0545 kg = 54.5 g

Calculate the mass of the cap in grams.

Solution The volume of the pipe portion of the cap can be determined by the volume of cylinder based on the inner and outer diameter of the PVC pipe: Vcap−pipe = Lpipe (Aouter − Ainner ) = Lpipe × π�4 (D2outer − D2inner )

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1-10

Solution and Answer Guide:

Vcap−pipe = �1.05 in ×

0.0254 m � in

× π�4 ��1.30 in × = 2.19 × 10−5 m3

0.0254 m 2 0.0254 m 2 � − �[1.30 − 0.13 × 2] in × � � in in

The volume of the solid end of the cap, although slightly rounded, may be closely approximated by the volume of a solid flat disk Vcap end = height x area = �0.13 in ×

0.0254 m 0.0254 m 2 � × π�4 �1.30 in × � = 2.83 × 10−6 m3 in in

mcap = VPVC × ρPVC = (2.19 × 10−5 + 2.83 × 10−6 ) m3 × 1330

kg� m3 = 0.033 kg = 33 g

d. Calculate the mass of the complete assembly of the pipe, water, and two caps.

Solution 𝑚𝑚𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎 = 𝑚𝑚𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 + 𝑚𝑚𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝 + 2 × 𝑚𝑚𝑐𝑐𝑐𝑐𝑐𝑐 = 56.7 + 54.5 + 2 × 33 = 177 g

1.27 Considering the precision that we will be able to attain in building the balance, is it acceptable to disregard the dome-shaped end of the cap and assume a flat shape for your calculations? Why or why not?

Solution The end caps comprise approximately 37% of the total mass of the assembly. The disk portion of the end cap is about 4% of the total assembly mass. Even if the curvature of the end cap resulted in an error of 25%, it would still be less than a 1% total error in the mass.

Manufacturing the total balance assembly by hand is likely to introduce other manufacturing variability and uncertainty much greater than 1%. Thus, it is reasonable to assume for this product and assembly method that the end cap is flat. If manufacturing tolerances required were much greater and more precise, a more detailed calculation could be required.

1.28 Calculate the weight of a wooden beam that is 1.75 cm X 3.6 cm in cross section whose length, X, is 50 cm + Z cm, where Z = the last digit of your student ID number.

Solution First, calculate the density of the wood from the information provided: 𝜌𝜌𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 =

𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚

𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣

=

64.5 g

1.75 × 3.6 × 20 cm3

g = 0.51 �cm3

The example used Amy’s last digit of their ID number = 6, so for this solution assume the length of the beam is 56 cm.

The mass of the wooden beam is:

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1-11

Solution and Answer Guide:

g 𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 = 𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣𝑣 × 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑 = (1.75 × 3.6 × 56 cm3 ) × 0.51 �cm3 = 181 g

1.29 Add 47.5 g for the hardware and the mass of the wood to the total weight of the components of the aluminum counterbalance assembly.

Solution Mass of the counterbalance assembly = 47.5 + 10.6 = 58.1 g 1.30 The balance’s beam shown in Figure 1.12 is to be held by a pin, placed at point Y. The aluminum bar will be held on a nail at one end. The PVC tube holding two ounces of water will be suspended from a nail at the other end of the beam. Sketch the beam and the point where the beam is attached to a vertical frame. Also show the forces and the direction of the forces acting on the beam from the aluminum counterbalance on the right-hand side of the beam and the water-filled PVC tube on the left-hand side of the beam.

Solution

1.31 For a beam of a given length, X, where X is the beam length determined in Problem 1.28, determine the position, Y, where the moments associated with the water-filled PVC tube will be equal to the moment associated with the aluminum counterbalance and the beam will be perfectly balanced horizontally. Recall that the force associated with each part was determined above.

Solution For the forces to balance, the counterclockwise moment of the force acting on the counterbalance assembly must equal the clockwise moment of the force acting on the distributed weight of the wooden beam. Applying the force balance equation yields:

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1-12

Solution and Answer Guide:

Momentclockwise = Momentcounterclockwise The Moment is equal to the force multiplied by the distance to where the force acts.

The PVC waterweight acts counterclockwise at a distance of Y from the pin. The weight of the aluminum counterbalance acts clockwise around the pin at (X-Y). The moment and force associated with the weight of the wood beam acts at a distance defined by {Y + (X - 2Y)/2}.

For the example case where the beam length, X, is 56 centimeters long: 𝐹𝐹𝑃𝑃𝑃𝑃𝑃𝑃 × 𝑌𝑌 = 𝐹𝐹𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 × �𝑌𝑌 + �

𝑋𝑋 − 2𝑌𝑌 �� + 𝐹𝐹𝐴𝐴𝐴𝐴 × {𝑋𝑋 − 𝑌𝑌} 2

𝑋𝑋 − 2𝑌𝑌 �� + 𝑚𝑚𝐴𝐴𝐴𝐴 × 𝑔𝑔 × {𝑋𝑋 − 𝑌𝑌} 2

𝑚𝑚𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑒𝑒 × 𝑔𝑔 × 𝑌𝑌 = 𝑚𝑚𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 × 𝑔𝑔 × �𝑌𝑌 + �

56 − 𝑌𝑌 �� + 57.6 × 9.81 × (56 − 𝑌𝑌) 2

177 × 9.81 × 𝑌𝑌 = 47 × 9.81 × �𝑌𝑌 + �

1.74 𝑌𝑌 = 0.466𝑌𝑌 + {0.466 × (28 − 0.5 𝑌𝑌)} + 0.104 × (56 − 𝑌𝑌) 1.40 𝑌𝑌 = 18.8 𝑌𝑌 = 13.4 cm

To balance the PVC-water weight and the Al counterbalance, the hole in the wooden beam should be drilled 13.4 cm from the left side of a 56 cm-long beam.

1.32 Using tools provided to you, construct a balance and place it on a pin on a stand or one available in the classroom. Is your beam perfectly balanced (i.e., does it hang from the pin in a perfectly level and horizontal position)? Describe possible sources of error in the construction of the beam that might cause the beam to be less than perfectly balanced.

Solution Sources of error in manufacturing can be measuring errors, rounding errors, and lack of precision in placement of the components, the pin-hole, and cutting.

1.33 In the days before common currency, merchants may have developed poor reputations if people felt they were being cheated. Would it be relatively simple or difficult to change the way a scale behaved if a merchant were trying to balance coppers (copper coins) and receive an adjusted weight in silver? Describe how a dishonest merchant might “tip the scales.”

Solution Copper has a density of 8.92 g/cc while silver has a density of 10.49 g/cc. Since copper is lighter, the same size copper piece will way look larger than the same size silver piece. If the

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1-13

Solution and Answer Guide:

pin in the balance beam is slightly off-center when the balance is put together, the balance point can be adjusted to make the same size silver piece appear to be balanced by the same size copper piece. But in actuality, if the merchant receives silver in exchange for the same size (volume) of copper, the merchant will end up ahead with a greater mass of silver.

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1-14

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 2: Measurements and Experiments: Data and Decisions with Sensors, Radios, and Arduinos

Solution and Answer Guide Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 2: Measurements and Experiments: Data and Decisions with Sensors, Radios, and Arduinos

Chapter 2 Questions

2.1 What are some things of interest to you that you would like to measure? What would you hope to learn about these measurements?

Solution Answers may vary.

Excellent

Good

Answers show thought about what steps are considered in making a measurement and concepts of time, cost, precision and accuracy

Answers show some thought about what steps are considered in making a measurement and some concepts of time, cost, precision and accuracy

Needs Improvement Answers show minimal thought about what steps what steps are considered in making a measurement and concepts of time, cost, precision and accuracy

Poor

Unacceptable

Answers partially address the steps considered in making a measurement and little concepts of time, cost, precision and accuracy

Missing or answer an unrelated question

2.2 Consider a time when you worked with someone from a different background or interest.

This could be something for school or in your personal life. In that experience, where did you all have commonality? Where did you have differences? What lessons did you take away from that experience?

Solution Answers may vary. Answers should include a commonality, a difference, and a lesson taken from experience.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

2-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 2: Measurements and Experiments: Data and Decisions with Sensors, Radios, and Arduinos

2.3 From the list of sensors in Table 2.1, which would you use to measure how active a person is throughout the day? How would your choice of sensor change if it was worn on a person or if it was fixed in the environment?

Solution The answer should either include the accelerometer or the ultra-sonic range finder. The first would be if the sensor was fixed in the environment and the second would work better if worn on a person.

2.4 Find a sensor that you believe is interesting on SparkFun. What kinds of interesting applications could that sensor be used for? How could they be helpful in daily life?

Solution Answers may vary. Answers should include an application of the technology and a use in daily life.

2.5 What would be the expected range for a device measuring human body temperature? What would be the range for measuring the temperature within a residential building?

Solution Answers may vary. For human body temperature, answers should be around the wide range of 32℃ − 43℃ (90℉ − 110℉). Residential building temperature ranges should be a larger range around the values of 15℃ − 43℃ (60℉ − 110℉).

2.6 If a device measuring distance has a precision of 5 meters, what would be the range of possible measurements if an object was actually 10 meters away?

Solution Calculate the upper bound of the range (10 meters + 5 meters = 15 meters) Calculate the lower bound of the range (10 meters − 5 meters = 5 meters) The range of the device measuring distance would be 5 meters – 15 meters.

2.7 Imagine you are selecting sensors for the next generation of autonomous vehicles. Each vehicle will need to know how close it is to other objects. What level of precision is needed in the distance sensors placed in the car? Justify your responses.

Solution Answers may vary but should be limited to a lower range of distance values. The justification should consider that autonomous vehicles need a higher level of precision to avoid road accidents and injuries.

2.8 What would be an appropriate sampling rate for monitoring a person’s body temperature during exercise? Justify your response.

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2-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 2: Measurements and Experiments: Data and Decisions with Sensors, Radios, and Arduinos

Solution Answers may vary but should be reasonable for measuring human body temperature.

Justification may include the rate at which human body temperature may change is not fast enough to result in higher sampling rates.

2.9 If a sensor completes a measurement once every 5 seconds, what is the sampling rate in Hertz? What if the device takes a measurement once every millisecond?

Solution The sampling rate if samples are taken every 5 seconds: 1

Sampling Rate =

5s

= 0.2 Hz

Sampling Rate =

0.01s

The sampling rate if samples are taken once every millisecond: 1

= 1000 Hz

2.10 In selecting digital interfaces, which should be chosen to transfer the most data in the shortest possible time? If controlling the flow of data during transmission is important, which interface should NOT be selected?

Solution To transfer the most data in the least amount of time, SPI should be selected because it has the highest typical transfer rate of 5 Mbps. If controlling the flow of data during transmission is important, UART should not be selected since it does not have flow control.

2.11 For the signal in Figure 2.9, what are the maximum and minimum values? At what time do these values occur?

Solution The maximum value is around 5.0 V, and it occurs between 0.2 – 0.3 seconds. The minimum value is 0 V, and it occurs between 0.7 – 0.8 seconds.

2.12 For an ADC with a range of 10 V and 8-bit resolution, what integer code will be reported for a voltage measurement of 7.34 V? Solution Finding the integer code: Integer Code = ��

7.34 V 10 V

� (28 )� = ⌊187.904⌋ = 187

2.13 Would an ADC with a 10-V range and 8-bit resolution be capable of distinguishing between values that are 5 mV apart? Calculate the resolution limit and justify your response.

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2-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 2: Measurements and Experiments: Data and Decisions with Sensors, Radios, and Arduinos

Solution Finding the resolution limit: limit =

5V 28

= 0.018 V = 18 mV

From this value, the conclusion can be drawn that the ADC would not be able to distinguish between values 5 mV apart since the resolution limit is 18 mV.

2.14 For the following set of values, calculate the average and standard deviation: 2, 6, 29, -5, 1, 7, and 9.

Solution Using the equation for average: 𝜇𝜇 = 𝜇𝜇 =

1

𝑁𝑁

∑𝑁𝑁 𝑖𝑖=1 𝑥𝑥𝑖𝑖 =

1 7

1

𝑁𝑁

∑𝑁𝑁 𝑖𝑖=1 𝑥𝑥𝑖𝑖 the result would be: 1

∗ (2 + 6 + 29 − 5 + 1 + 7 + 9) = ∗ 49 = 7 7

Using the equation for standard deviation and the result from the average calculation, the result would be: 𝜎𝜎 = �

2 ∑𝑁𝑁 𝑖𝑖=1(𝑥𝑥𝑖𝑖 − 𝜇𝜇) 𝑁𝑁

1 = � ∗ [(2 − 7)2 + (6 − 9)2 + (29 − 7)2 + (−5 − 7)2 + (1 − 7)2 + (7 − 7)2 + (9 − 7)2 7 = 9.95

2.15 Consider a radio-based device that you utilize in daily life. What is its purpose? How far is its effective range?

Solution Answers may vary. Answers should include any device used in daily life and its effective range.

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2-4

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

Chapter 3 Questions

3.1 Reflect on your own childhood and family upbringing. What is the earliest instance in which you can remember engaging in structural engineering–like activity (i.e., assembling toys, building a doghouse, digging postholes, setting a broken bone)?

Solution Sample solution Answers may include the following: building blocks, building with Legos, breaking bones, assembling furniture, etc.

3.2 Reflect on knowledge that your family holds and passes down from generation to generation. Is there an activity, practice, or skill that has been passed down to you (e.g., artistry, baking or cooking, painting, quilting, woodworking)? How is that activity empirical in nature? Have there been instances where you learned new knowledge (perhaps through failure) and intend to pass it on to other persons in the future?

Solution Sample solution Cooking is empirical knowledge. My mother taught me how to cook using the knowledge she learned from her mother and grandmother. I was able to take that knowledge and add to it and teach her new things. I would make mistakes when cooking and call upon her to help me and fix the mistakes the best we could. Other times we would combine our knowledge to make a whole new idea.

3.3 Lumber is a construction material used in many structural systems, like residential homes and low-rise commercial structures. Lumber is sourced from a variety of tree species, which the American Wood Council (awc.org/) has cataloged in their National Design Specification for Wood Construction with Commentary. Consider an eight-foot-long piece of “2 × 4” pine (pine, Southern yellow). Sketch the actual dimensions of the “2 × 4” (Hint: It is not 2.0 inches by 4.0 inches) and calculate the gravity load associated with this member in a larger structural system. Report your answer in lbf/foot. Assume the unit weight is approximately 50 pcf.

Solution Part A: 8 ft × 1.5 in × 3.5 in = 8 ft × 0.125 in × 0.29 ft = 0.282 ft 3 Part B: 50 pcf x (1.5/12) feet x (3.5/12) feet. Answer = 1.822 lbf/foot.

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3-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

3.4 Multistory school buildings contain a variety of spaces in which human foot traffic and configurable furniture (e.g., desks) can impart live loads on each floor of the structure.

ASCE/SEI 7 states that the live load for classrooms shall be 40 psf, the live load for first-floor corridors shall be 100 psf, and the live load for corridors above the first floor shall be 80 psf.

Determine the dimensions of the classroom that you are situated in and sketch a detailed floor plan of the nearby classrooms and corridors to the nearest inch. Calculate the service load (in units of lbf) for the floor plan you have sketched. Additionally, speculate why corridors above the first floor have a reduced live load value.

Solution Sample solution A classroom is measured to be 10-ft x 10-ft, meaning its area is 100 ft2. If on the first floor, the live load is 40 psf. If it is a second-floor classroom, 40 psf still applies. Some might interpret this as a point load of 100 x 40 = 4,000 lbf. This value is only the resultant load; the distributed load over the floor area is of principal concern. On the ground floor, a hallway might measure to be 4-ft x 10-ft, meaning 40 ft2. Its live loading would be 100 psf. The resultant load is 4,000 lbf. If on the second floor, the live loading is 80 psf. The resultant load is 8,000 lbf.

3.5 Consider your current classroom or building. Inventory the construction materials that you can observe (e.g., clay brick, cinder block masonry, reinforced concrete, lumber, steel, glass).

Based on any relevant contextual information you can find about the structure that you are in (e.g., when it was built), speculate on where each of your inventoried construction materials likely originated from. Did any of the materials come from the municipality itself?

From the state? From elsewhere in the country? From elsewhere in the world?

Solution Sample Solution Answers may include the following: wood, metal, cotton, plastic, paper, etc., from locations such as China, Brazil, Canada, California, etc.

3.6 Locate two rulers so that you can use one ruler to measure the other. Measure the dimensions of the cross-sectional area of one of the rulers to the nearest millimeter.

Calculate the area moment of inertia, I, for its two orientations (e.g., x and y) when subjected to bending in the x- and y-directions. Which value is higher? Which value is lower? How do these values correspond to your ability to physically bend the ruler along the x- and y-axes?

Comment on your effort.

Solution Sample solution A ruler might have a cross section of 0.1 inch and 1 inch. It is essentially prismatic, so I = 1/12 bh3. Along its strong axis, I = 1/12 (0.1 inch) x (1.0 inch) 3 = 8.33x10-3 in4. Along its weak axis, I = 1/12 bh3 = 1/12 (1.0 inch) (0.1 inch)3 = 8.33x10-5 in4. It is easier to “bend” the ruler along its weak axis rather than its strong axis.

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3-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

3.7 Students at many colleges and universities enjoy socializing at homes and apartments that have cantilever-style balconies. A cantilever is a simple structural member that is firmly affixed at one end and has an external load imparted along its length and/or at its end. It can become extremely dangerous when these balconies are overloaded with too many people, whereby the end deflection, δ, becomes very large and the internal forces become larger than the ultimate strength of the material, resulting in catastrophic failure. Consider a cantilever beam, AB, made up of an eight-foot pine (Ponderosa) “2 × 4” with an elastic modulus, E, of 7.5 ksi. Calculate the end deflection, δ, if the end of the beam is subjected to a concentrated point load, P, of 60 lbf. Note that the units of ksi and psi are related in that psi is pound-force per square inch and ksi is kips per square inch. One kip equals 1,000 lbf.

Solution

δ = PL3 / 3EI P = 60 lbf or 0.06 kips L = 8 feet or 96 inches E = 7.5 kips/in2 I = bh3 / 12, where b = 1.5 inches or 3.5 inches h = 3.5 inches or 1.5 inches

δ = PL3 / 3EI = (0.06 kips) (96 inches)3 / 3 (7.5 kips/in2) (1/12) (1.5 in) (3.5 in)3 = 440.21 inches.

Way too much deflection!

3.8 Consider the previous problem of the cantilever-style beam AB. If the material changed from pine (Ponderosa) to steel (Esteel = 29 × 103 ksi), calculate the revised end deflection of the cantilever beam. Is the calculated value better or worse for a structural engineer? What other factors must the structural engineer consider in deciding between lumber or steel for this specific structural scenario?

Solution

δ = PL3 / 3EI P = 60 lbf or 0.06 kips L = 8 feet or 96 inches

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3-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

E = 29x103 kips/in2 I = bh3 / 12, where b = 1.5 inches or 3.5 inches h = 3.5 inches or 1.5 inches

δ = PL3 / 3EI = (0.06 kips) (96 inches)3 / 3 (29x103 kips/in2) (1/12) (1.5 in) (3.5 in)3 = 0.114

inches. Much more reasonable deflection for a 96-inch span!

The structural engineer must also consider availability of materials, etc. If wood must be used, e.g., then perhaps a wooden truss structure must be designed.

3.9 In your own words, explain the three responsibilities of a structural engineer.

Solution Sample solution Practice what you know and are educated and are educated in only, to assess structural integrity of a building to be safe for inhabitants and useable after disasters, and meets the needs of society utilizing Earth’s natural resources to reach these goals.

3.10 Consider the problem of the cantilever-style beam AB that uses steel. Assume that your calculated end value is the maximum allowable value before failure occurs. If a safety factor of 2.5 is applied, then what is the recommended limit on the concentrated end load for the structural design?

Solution For the answer found previously, treat it as Capacity. Insert to FOS = Capacity / Demand = 2.5 Solve for Demand.

From δ = PL3 / 3EI, since δ and P are linearly related, then the maximum end load is P = 24 lbf.

3.11 Conduct research on at least one energy-absorbing technology or sacrificial member used in structural systems (e.g., lead-rubber bearings, steel plate shear walls, controlled rocking, tuned mass dampers, seismic cloaking). In your own words, summarize your understanding of your selected system and its application to structural engineering design.

Solution Sample solution

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3-4

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

Rubber supports areas of high stress and can act as a hydraulic stopper. Rubber has effective and versatile use that can be used in a variety of structures.

3.12 Conduct research on the United Nations’ 17 Sustainable Development Goals. In your own words, explain how at least one of these goals relate to structural engineering design processes.

Solution Sample solution Goal 2 - Sustainable Cities and Communities. This goal aims to increase the number of cities, create sustainable and resilient buildings with the resources available in the environment.

This goal uses structural engineering to better society’s communities to work towards safe, sustainable, and inclusive cities.

3.13 Conduct research on the typical shape of truss structures and framed structures.

Differentiate the similarities and differences of their defining characteristics in a Venn diagram.

Solution Sample solution Truss and framed structures are similar because they both can carry loads and are used in infrastructure. They differ as trusses are a triangle design and can freely rotate.

3.14 Sketch two two-dimensional drawings of a 50-foot-wide and 100-foot-tall office building. In your first sketch, use truss structural members in your design where no individual member exceeds 14 feet. In your second sketch, use truss structural members in your design where no individual member exceeds seven feet. Compare and contrast your designs. Speculate on specific scenarios where seven feet and 14 feet are appropriate limits for disparate structures.

Solution Sample solution Sketches will vary. In the second design where the linear length is limited to 7 feet, there will be far more joints, and shorter spans. Wooden structures might need this type of design.

The longer spans might need steel.

3.15 Sketch two two-dimensional drawings of a 50-foot-wide and 100-foot-tall office building. In your first sketch, use framed structural members in your design where no individual member exceeds 10 feet. In your second sketch, use framed structural members in your design where no individual member exceeds 20 feet. Compare and contrast your designs.

Speculate on specific scenarios where 10 feet and 20 feet are appropriate limits for disparate structures.

Solution Sample solution

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3-5

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

Sketches will vary. Various factors (e.g., material) affect the selection of one framed structure over another.

3.16 Consider the vertical post the center of the truss holding up the roof structure of the patio deck shown in Figure 3.25. Sketch an idealization of the center post whereby its linear length communicates three nodes of interest: the connection at the base, the connection with the bracing supports, and the connection at the top. Justify your placement of any internal hinges where small rotations are allowed to occur.

Solution The connection at the base: the areas where the roof meets the beams should be circled.

The connection with the bracing supports: the areas where the smaller beams connect to the larger beams should be circled.

The connection at the top: the center truss at top of the roof should be circled.

3.17 Consider the cantilever beam shown. Calculate the reactionary forces at B. Indicate the direction of the reactionary forces (i.e., up, down, left, right, clockwise, or counterclockwise).

Solution RBy = - P, arrow up Our assumption is opposite of what is true, so RBy = P, arrow down RBx = 0 MB = - PL, counterclockwise Our assumption is opposite of what is true, so MB = PL, clockwise

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3-6

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

3.18 Consider the cantilever beam shown. Calculate the reactionary forces at B. Indicate the direction of the reactionary forces (i.e., up, down, left, right, clockwise, or counterclockwise).

Solution RBx = - Pcos 45, right arrow Pcos 45, left arrow RBy = Psin 45, down arrow MB = PLsin 45, clockwise arrow 3.19 Consider the cantilever beam shown. Calculate the reactionary forces at B. Indicate the direction of the reactionary forces (i.e., up, down, left, right, clockwise, or counterclockwise).

Solution RBx = Pcos 30, right arrow RBy = Psin 30, up arrow MB = PLsin 30, counterclockwise arrow

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

3-7

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

3.20 Consider the cantilever beam shown. Calculate the reactionary forces at B. Indicate the direction of the reactionary forces (i.e., up, down, left, right, clockwise, or counterclockwise).

Solution RBx = P, right arrow RBy = 0 MB = PL, clockwise arrow

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

3-8

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

3.21 Consider the cantilever beam shown. Calculate the reactionary forces at B. Indicate the direction of the reactionary forces (i.e., up, down, left, right, clockwise, or counterclockwise).

Solution RBx = Pcos 30, left arrow RBy = Psin 30, down arrow MB = PLcos 30, counterclockwise arrow

3.22 A structural engineer is asking for your help in meeting a client’s needs. The client owns a business specializing in dolphin boat tours along the beach. The client would like to erect a very large flagpole outside of their business near the beach that would feature a prominent flag that advertises the boat tours. The client is insisting to use a very long pine (Ponderosa) “2 × 4” and would like to have the flagpole be as tall as possible. The structural engineer says that any deflection at the top of the flagpole should be limited to 1/300th the length of the flagpole (e.g., only one inch of horizontal deflection is allowed for a 300-inch-tall flagpole). Assume that the maximum reactionary force that the pine (Ponderosa) flagpole can sustain at its base is approximately 30,000 lbf. What is the tallest flagpole that you recommend for this client’s needs? Justify your recommendation.

Solution Apply a variable P load to the end of a cantilever beam, which equals the reactionary maximum force. Use equilibrium to solve that the variable applied P = 30,000 lbf.

Determine whether this end point load generates a deflection that is larger than the allowable deflection. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

3-9

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

δ = PL3 / 3EI, where δ = L/300 so 1/300L2 = P / 3EI or 1/L2 = 100 P / EI L2 = EI / 100 P P = 30,000 lbf or 30 kips E = 7.5 kips/in2 (ponderosa) I = bh3 / 12, where b = 1.5 inches or 3.5 inches h = 3.5 inches or 1.5 inches L2 = EI / 100 P = (7.5 kips/in2) (1/12) (1.5 in) (3.5 in)3 / 100 (30 kips) = 0.0133 in2 L = 0.115 inches. A VERY SHORT FLAGPOLE! 30 kips is actually quite large, so the material itself (ponderosa) is likely to have failed by then (mechanics of materials – in a future class).

3.23 The client who owns the dolphin boat tours just realized that they also have a very long piece of 2.5-inch-diameter steel rod that they can use for their flagpole. The structural engineer continues to advise that any deflection at the top of the flagpole should be limited to 1/300th the length of the flagpole. Assume that the maximum reactionary force that the steel flagpole can sustain at its base it approximately 240,000 lbf. What is the tallest flagpole that you recommend for this client’s needs? Justify your recommendation.

Solution Apply a variable P load to the end of a cantilever beam, which equals the reactionary maximum force. Use equilibrium to solve that the variable applied P = 240,000 lbf.

Determine whether this end point load generates a deflection that is larger than the allowable deflection.

δ = PL3 / 3EI, where δ = L/300 so 1/300L2 = P / 3EI or 1/L2 = 100 P / EI

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

3-10

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

L2 = EI / 100 P P = 240,000 lbf or 240 kips E = 29e3 kips/in2 (steel) I = pi*R4 / 4, where R = 2.5/2 inches or 1.25 inches Similarly L2 = EI / 100 P = (29e3 kips/in2) (3.14) (1/4) (1.25 in)4 / 100 (240 kips) = 2.32 in2 L = 1.52 inches. A slightly taller flagpole, but still ridiculously short! The use of the much larger 240 kips as opposed to 30 kips is really constraining the overall height of the flagpole.

3.24 The client who owns the dolphin boat tours is also in possession of bolts and anchors that can each support 500 lbs of lateral (i.e., shear) force, which occur in the same direction as the horizontal reactionary forces at the base of the flagpole. The structural engineer advises you that the typical arrangement for how these bolts might connect to the concrete foundation is square (four bolts) or circular (six bolts). With this new constraining information in your hands, what is the tallest pine and steel flagpole that you recommend for this client’s needs? Justify your recommendation.

Solution These bolts limit the actual reactionary force values and bring us back down to reality. In a 4 bolt arrangement, the maximum reactionary force is 2,000 lbf or 2 kips. In a 6 bolt arrangement, the maximum reactionary force becomes 3,000 lbf or 3 kips. Evaluate P as 2 kips or 3 kips.

Ponderosa

δ = PL3 / 3EI, where δ = L/300 so 1/300L2 = P / 3EI or 1/L2 = 100 P / EI L2 = EI / 100 P P = 3,000 lbf or 3 kips E = 7.5 kips/in2 (ponderosa)

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

3-11

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

I = bh3 / 12, where b = 1.5 inches or 3.5 inches h = 3.5 inches or 1.5 inches L2 = EI / 100 P = (7.5 kips/in2) (1/12) (1.5 in) (3.5 in)3 / 100 (3 kips) = 0.133 in2 L = 0.366 inches. A VERY SHORT FLAGPOLE!

Steel

δ = PL3 / 3EI, where δ = L/300 so 1/300L2 = P / 3EI or 1/L2 = 100 P / EI L2 = EI / 100 P P = 240,000 lbf or 240 kips E = 29e3 kips/in2 (steel) I = pi*R4 / 4, where R = 2.5/2 inches or 1.25 inches Similarly L2 = EI / 100 P = (29e3 kips/in2) (3.14) (1/4) (1.25 in)4 / 100 (3 kips) = 185 in2 L = 13.6 inches. A flagpole standing at over a foot! What the student must realize is that our members are too small; we need a larger cross section in order to have more bending resistance.

3.25 The client who owns the dolphin who owns the dolphin boat tours would like their flagpole to be environmentally sustainable in order to align with their efforts of promoting marine conservation. Based on the carbon dioxide emissions generated per ton of raw material for the two designs you have generated (pine and steel), which do you recommend for this client’s needs? Justify your recommendation.

Solution Sample Solution

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3-12

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 3: Structures and Society: Structural Engineering Problem-Solving Techniques to Design Long-Lasting Solutions

I would recommend pine for the client’s needs. Wood is more sustainable because it produces less carbon that could harm the nearby wildlife. It is a more natural material that would align with conservation efforts because it mimics nature.

3.26 The client who owns the dolphin boat tours would like to move forward with the more affordable design. Based on the present-day market prices for the two designs you have generated (pine and steel), which do you recommend for this client’s needs? Justify your recommendation.

Solution Sample Solution The current price of steel is $0.03 - $0.05 USD per pound and the current price of pine (in Virginia) is $10 - $23.50 (varies based on the type of pine). Longleaf pine is $1.29 per pound; therefore, I would recommend steel to the client. Steel is cheaper per pound in comparison to the price per pound of Longleaf pine. It is more affordable and it is better suited long term use.

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3-13

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Chapter 4 Questions

4.1 Describe the concept of sustainability.

Solution Sample solution; answers may vary.

Everything that we need for our survival and wellbeing depends, either directly or indirectly, on our natural environment. Sustainability creates and maintains the conditions under which humans and nature can exist in productive harmony and that permits fulfilling the social, economic, and other requirements of present and future generations. Sustainability is important to making sure that we have and will continue to have the water, materials, and resources to protect human health and our environment.

4.2 How is “sustainability” different from “sustainable development”?

Solution Sample solution; answers may vary.

Sustainability is the coexistence of humanity and nature that meets all needs of humans directly and indirectly. Sustainable development is the desire to improve the standard of living and the effects it will have environmentally and economically.

4.3 What tangible indicators can be measured to demonstrate if sustainability is being achieved?

Solution Sample solution; answers may vary.

Amount of water used.

Life cycle of the product.

Raw materials used.

Carbon footprint.

Carbon dioxide emissions during transit.

Handling of diversity.

Equality policies.

Support for balancing work and family life.

Flora and fauna protection.

Prevention of deforestation and afforestation.

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4-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Percent of energy from renewable resources.

Waster generation/reduction.

Human development index.

Health (maternal, infant, etc.) and lifespan.

Useful resources: A framework for Sustainability Indicators at EPA. EPA/600/R/12/687.

October 2012. https://www.epa.gov/sites/default/files/2014-10/documents/frameworkfor-sustainability-indicators-at-epa.pdf (accessed 4/5/2023) 4.4 List the categories of the SDGs that might require the knowledge and skill set of professional engineers.

Solution Justification of solutions may vary.

1. no poverty; 2. zero hunger; 3. good health and well-being; 4. quality education; 5. gender equality; 6. clean water and sanitation; 7. affordable and clean energy; 8. decent work and economic growth; 9. industry, innovation, and infrastructure; 10. reduced inequalities; 11. sustainable cities and communities; 12. responsible consumption and production; 13. climate action; 14. life below water; 15. life on land; 16. peace, justice, and strong institutions; 17. and partnerships for the goals Useful resources: United Nations Department of Economic and Social Affairs: Sustainable Development – The 17 Goals https://sdgs.un.org/goals 4.5 Identify two of the SDGs you listed above that you are most personally interested in and describe why you have an interest in those specific goals.

Solution Sample Solution; answer may vary.

1. Climate action interests me because it is such a pressing issue that is repeatedly ignored that impacts millions. I would enjoy tackling this issue to make a difference for millions.

2. Sustainable cities and communities interest me because I've always wanted to live in a city, and I would like to implement more green cities. I think a city designed with

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4-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

greenery can be very beneficial, as it would aid in decreasing air pollution and climate change. It could also provide food for the homeless populations.

4.6 Describe the engineering knowledge and skills that might be required to address two of the SDGs listed in the question above.

Solution Sample solution; answers may vary.

1. Climate Action may require knowledge in environmental engineering and environmental policy.

2. Sustainable cities and communities may require knowledge in urban planning, architectural engineering, civil engineering, and civil planning.

4.7 Describe how the U.S. Bureau of Labor and Statistics defines a civil engineer, the entry-level education required, and the median salary for civil engineers by reviewing the Field of Degree highlights for students and job seekers in the Occupational Outlook Handbook.

Solution Sample solution; answers may vary. Median salary is $88,050 with a bachelor’s degree.

Useful resources: U.S. Bureau of Labor and Statistics, Occupational Outlook Handbook. https://www.bls.gov/ooh/architecture-and-engineering/home.htm 4.8 Describe how the U.S. Bureau of Labor and Statistics defines an environmental engineer, the entry-level education required, and the median salary for environmental engineers by reviewing the Field of Degree highlights for students and job seekers in the Occupational Outlook Handbook.

Solution Sample solution; answers may vary. Median pay is $96,820 with a bachelor’s degree. https://www.bls.gov/ooh/architecture-and-engineering/home.htm 4.9 Find job listings for a civil engineering position and an environmental engineering position.

Describe the similarities and difference between the education required, experience required, and salary range (if available) for two positions. What other educational degrees or requirements would be acceptable for the job listing you have found? You can find job listings through employment websites, USAJobs.gov, ASCE.org, LinkedIn, and other professional networking websites.

Solution Sample solution; answers may vary.

Similarities include both positions are competitive and may require travel. Differences include promotional potential, the duties performed, and pay.

Useful resources: ASCE Career Connections: https://careers.asce.org/jobs/

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4-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

4.10 What regulatory agencies are responsible for ensuring that the drinking water on your campus is safe to drink?

Solution The U.S. EPA sets legal limits on over 90 contaminants in drinking water. The legal limit for a contaminant reflects the level that protects human health and that water systems can achieve using the best available technology. EPA rules also set water-testing schedules and methods that water systems must follow. The Safe Drinking Water Act (SDWA) gives individual states the opportunity to set and enforce their own drinking water standards if the standards are at a minimum as stringent as EPA's national standards.

Useful resources: USEPA Drinking Water Regulations: https://www.epa.gov/dwreginfo/drinking-water-regulations 4.11 Climate change has severely increased the likelihood that severe floods, hurricanes, and tornadoes will impact the infrastructure even in relatively high-income developed nations.

How might these events impact both water supply and sanitation services?

Solution Sample Solution: Droughts and floods are forcing people to flee their homes. Flooding decreases access to safe drinking water since it disrupts sanitation services and contaminates drinking water supply.

Useful resources: International Panel on Climate Change Sixth Assessment report: Impacts, Adaptation and Vulnerability, Chapter 4: Water https://www.ipcc.ch/report/ar6/wg2/chapter/chapter-4/ International Panel on Climate Change Sixth Assessment report: Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. https://www.ipcc.ch/report/managing-the-risks-of-extreme-events-and-disasters-toadvance-climate-change-adaptation/ 4.12 List the steps in a disaster response plan and describe the role an experienced engineer might play in responding to a natural disaster.

Solution The rapid, immediate, and short-term actions circumjacent to a disaster are known as disaster response. Disaster response plans should include: Potential Issues Transportation Communications Public Works and Engineering Firefighting

Traditional Engineering Job Title of Response Coordinator Civil/Transportation Engineer Electrical/Communications Engineer Civil Engineer Transportation and Structural Engineer

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4-4

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Information and Planning Mass Care, Emergency Assistance, Temporary Housing, and Human Services Logistics Public Health and Medical Services Search and Rescue Oil and Hazardous Materials Response Agriculture and Natural Resources Annex Energy Public Safety and Security Cross-Sector Business and Infrastructure

Industrial/System Engineer Interdisciplinary response team Industrial/System Engineer Interdisciplinary response team Geotechnical/Structural Engineer Chemical Engineer Agricultural/Biological Engineer Mechanical/Power Systems Engineer Interdisciplinary response team Civil/System Engineer

Useful resources: Federal Emergency Management Agency (FEMA) National Response Framework. https://www.fema.gov/emergency-managers/nationalpreparedness/frameworks/response 4.13 Hurricane Maria is the worst natural disaster on record to affect Dominica and Puerto Rico, and it is also the deadliest Atlantic hurricane since Hurricane Jeanne in 2004. Hurricane Maria caused catastrophic damage and numerous fatalities across the northeastern Caribbean. Total losses from the hurricane were estimated at upwards of $91.61 billion (2017 U.S. dollars), mostly in Puerto Rico, ranking it as the third-costliest tropical cyclone on record. Hurricane Maria forced many water and sanitation systems offline. How would someone determine if drinking water is safe after a possible system failure? Explain how lack of power and lack of water may have contributed to the high mortality rate associated with the hurricane.

Solution Sample solution; answers may vary.

Transportation systems were disrupted, making the repair and restoration services by energy and water repair technicians extremely difficult. Water and sanitation treatment facilities were inundated with flood water, resulting in insecure water supplies and lack of available care. Lack of water removal from infrastructure resulted in inundation of the electrical grid, halting much of the ability to provide urgent care.

Useful resources: Federal Emergency Management Agency (FEMA) Hurricane Maria Response and Relief Operations Underway: https://www.fema.gov/pressrelease/20210318/hurricane-maria-response-and-relief-operations-underway U.S. Army Corps of Engineers: The Longest Blackout in U.S. History: Hurricane Maria: https://www.usace.army.mil/About/History/Historical-Vignettes/Relief-andRecovery/154-Hurricane-Maria/ Federal Emergency Management Agency (FEMA) Five Years Later: Reflecting on Response Efforts After Hurricanes Harvey, Irma and Maria: https://www.fema.gov/blog/five-yearslater-reflecting-response-efforts-after-hurricanes-harvey-irma-and-maria

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4-5

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

4.14 What percentage of the population of Kenya has access to water in urban areas a. urban areas Solution 58% have access to safely managed services and an additional 29% have access to at least basic services rural areas according to the UN report on SDGs b. rural areas Solution 52% have access to at basic services

c.

Is access to clean water expected to get better or worse in the coming years?

Solution Access has been improving and is expected to continue to improve in future years.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

4-6

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Useful resources: United Nations, UN Water SDG 6 Data Portal: https://sdg6data.org/en 4.15 Create a digital story or poster that describes the SDGs that are related to Gilbert’s experience in Kenya. You may use one of the following technologies to help develop your submission: Canva, Piktochart, PowToon, Prezi, or Weebly.

Solution Answers may vary. Answers may include but are not limited to: • SDG region: SDG Sub-Saharan Africa • 62% of the population in Kenya uses a safely managed drinking water service (SDG indicator 6.1.1, 2020) • 33% of the population in Kenya uses a safely managed sanitation service (SDG indicator 6.2.1a, 2020) • 27% of the population in Kenya has a handwashing facility with soap and water available at home (SDG indicator 6.2.1b, 2020) • 87% of monitored water bodies in Kenya has good ambient water quality (SDG indicator 6.3.2, 2020) • 12$/m3 is the value added from the use of water by people and the economy in Kenya (SDG indicator 6.4.1, 2019) • 33% of the renewable water resources in Kenya is being withdrawn, after taking into account environmental flow requirements (SDG indicator 6.4.2, 2019) • 59% is the degree of implementation of integrated water resources management in Kenya (SDG indicator 6.5.1, 2020) • 27% of transboundary basin area has an operational arrangement for water cooperation (SDG indicator 6.5.2, 2020) • 23% of the water basins in Kenya is experiencing rapid changes in the area covered by surface waters (SDG 6 indicator 6.6.1, 2020) • 196 m$ is the amount of water- and sanitation-related official development assistance received by Kenya in 2020 (SDG indicator 6.a.1) © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

4-7

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Useful resources: United Nations, UN Water SDG 6 Data Portal: https://sdg6data.org/en 4.16 One example of a POU device that is simple to employ is a product called the AquaTab, which uses a solid chlorine-forming disinfectant process. In 2022, the cost for 100 tablets that each treat four gallons of water was $24.95 (U.S. dollars). The AquaTabs are simple to use in sub-Saharan Africa because the rural communities have already been exposed to the tablets before and the instructions for using the tablets are a part of the packaging. How much would it cost to use AquaTabs for one year as a POU treatment in a home that requires 80 L of water per day?

Solution The cost of treating one liter of water is: gallon 24.95 USD 1 tablet × × = 0.0165 USD�L 100 tablets 4 gallon 3.7854 L

Multiple the cost per liter by the number of liters required per year:

0.0165 USD�L × 80 L�d × 365 d�yr = 481.15 USD�yr

4.17 The average annual wage in Kenya in 2022 was approximately $1,524. What percent of the household income must be spent on AquaTabs if there is one wage earner in the home?

Compare this to how much you are accustomed to paying for water. (You may have to ask the person in your household who pays the water bill how much that expense costs per month and what the average household income is each year.) Does it seem like a reasonable expectation to expect to pay this percentage of the household income for water treatment in a Kenyan community that does not have a reliable water supply?

Solution Determine the percentage of annual income spent on treating water with AquaTabs in Kenya: Percentage of income for treated water in Kenya =

481.15 USD�yr × 100% = 31.6% 1524 USD�yr

Answers for individual water use and income may vary. An example based upon US average is: Each American uses an average of 82 gallons of water a day at home (USGS, Estimated Use of Water in the United States in 2015). Residential water costs in the United States average about $5.85 per thousand gallons. Thus, average annual water cost per person in the United State is: 82

gallon day

× 365

day

year

×

5.85 USD

1000 gallons

= 175.09 USD�yr

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4-8

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

According to the U.S. Census, the median household income is approximately 70,000 USD (2021), so the percent of income spent on water, on average would be: 175.09 USD�yr × 100% = 0.25% 70,000 USD�yr

The cost for this seemingly inexpensive treatment method is actually over 100 times more by relative income than what the average person in the United State spends on water! By comparison, financial advisors recommend spending less than 30% of income on rent or home mortgage. Kenyan’s might spend more for access to treated water than someone in the US spends on rent or home mortgage!

Useful resources: United States Environmental Protection Agency. Water Sense: Date and Information used for Water Sense. https://www.epa.gov/watersense/data-andinformation-used-watersense#Cost%20of%20Water East Bay Municipal District, East Bay, California. Understanding your bill: https://www.ebmud.com/customers/billing-questions/understanding-your-bill 4.18 Choose an alternative HWT option from the WHO Scheme. Use the information from the WHO evaluation (https://www.who.int/tools/international-scheme-to-evaluate-householdwater-treatment-technologies) and information you find online to compare an alternative process to the AquaTab water treatment process. You might consider cost, effectiveness, or other criteria in your evaluation.

Solution Solutions may vary Excellent

Good

Answers describe performance classification, treatment technology, and cost estimate

Answers describe performance classification, treatment technology, and may reference cost

Needs Improvement Answers describe performance classification and treatment technology only

Poor

Unacceptable

Answers partially address performance classification and treatment technology

Answers only address one aspect of the system or misinterpret multiple aspects of performance

Useful resources: World Health Organization. International Scheme to Evaluate Household Water Treatment Technologies: https://www.who.int/tools/international-scheme-toevaluate-household-water-treatment-technologies

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4-9

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

4.19 Consider what you know about how you would like your water to look, smell, and taste, as well as other characteristics of water quality. What characteristics are required for implementation of a sustainable POU water treatment system in a community in a lowincome country? Consider the technical, economic, social, and environmental factors that contribute to your definition of sustainable.

Solution Solutions may vary Excellent

Good

Answers accurately describe performance, treatment technology, maintenance required, aesthetics, waste production, and cost estimate

Answers accurately describe three aspects of a system: performance, treatment technology, maintenance required, aesthetics, waste production, and cost estimate

Needs Improvement Answers partially describe three aspects of a system: performance, treatment technology, maintenance required, aesthetics, waste production, and cost estimate

Poor

Unacceptable

Answers only address one aspect of the system or misinterpret multiple aspects of the system

Answers only address one aspect of the system or misinterpret many aspects of the system

Useful resources: World Health Organization. International Scheme to Evaluate Household Water Treatment Technologies: https://www.who.int/tools/international-scheme-toevaluate-household-water-treatment-technologies United States Environmental Protection Agency. Water Sense. https://www.epa.gov/watersense/data-and-information-usedwatersense#Cost%20of%20Water 4.20 Estimate the amount of water you consume each day from your water bill or from all your water-related activities, such as drinking, washing dishes, washing clothes, bathing/showering, cleaning, and so on. Your answer should have units of liters of water per day per person. Use mathematical calculations to show how you made your estimate. What type of POU/HWT device would meet your needs for water?

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4-10

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Solution Solutions may vary Excellent

Good

Answers accurately calculate comprehensive water use for drinking, washing dishes, washing clothes, bathing/showering, cleaning, and provide a home water treatment system that meets those requirements

Answers accurately calculate several water uses for drinking, washing dishes, washing clothes, bathing/showering, or cleaning, and provide a home water treatment system that meets most requirements

Needs Improvement Answers partially or inaccurately describes two water uses and lists an appropriate home water treatment system

Poor

Unacceptable

Answers inaccurately describes water uses and lists an appropriate home water treatment system

Answers fail to calculate water use and misinterpret many aspects of the home water treatment

Useful resources: Water Footprint Calculator: https://www.watercalculator.org/footprint/indoor-water-use-at-home/ World Health Organization. International Scheme to Evaluate Household Water Treatment Technologies: https://www.who.int/tools/international-scheme-to-evaluate-householdwater-treatment-technologies 4.21 Based on the materials list in Table 4.4 and the biosand filter schematic, create engineering drawings that can be used to fabricate a sand filter with the materials listed. List each part and illustrate how the parts will fit together.

Solution Answers may vary Excellent Good Name and scale are provided, design is appropriate, dimensions are clearly labeled, materials are called

Most drawing elements are present, including at least name, materials, and dimensions

Needs Improvement The drawing covers helpful information but details are missing including materials, dimensions, or other information (See example)

Poor

Unacceptable

The design is severely flawed or information about materials and dimensions is absent or not understandable

The design is severely flawed and information about materials and dimensions is absent or not understandable

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4-11

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Example of a typical hand drawn sketch which needs improvement:

4.22 Using Excel or a similar spreadsheet, calculate how much your filter materials cost. What parts are most expensive? Where might you be able to possibly achieve the greatest reduction in cost?

Solution Answers may vary

Material Sand Gravel Bucket spigot PVC pipe PVC cement Epoxy Male adapter Elbow Threaded elbow O rings

Amount 0.5 cubic feet 0.5 cubic feet

10 ft 1 pack 1 pack

Cost

Cost per filter

3.08 1 1

1 1 10 pack

Amount per filter

1

3.38 2.78 1.76 1.79 5.96 3.58 0.73 0.48 0.71 1.97

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4-12

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Other

Total

4.23 Construct your sand filter based on your design and engineering drawing using the tools and materials provided. Include a photo of your as-built sand filter.

Solution Answer may vary. It is important to allow students to make mistakes about spigot placement, materials placement, materials strength, etc. In this way, students can learn about hydrostatics, hydrodynamics, material compatibility, and materials strength through experience. An example solution may look something like:

4.24 Collect or use the tap water provided and test this water as a control test using the PathoScreen methodology (https://www.hach.com/asset-get.download.jsa?id=7639984011).

Report your results.

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4-13

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Solution Tap water should be gold in color. Examples of results are shown below with the black vial being positive (containing hydrogen sulfide producing bacteria that indicate pathogenic organisms may be present) and the gold vial indicating the likely absence of pathogenic organisms. Tap water should be gold in color:

Useful resources: Hach Pathoscreen Field Test Kit: https://my.hach.com/pathoscreenfield-test-kit/product?id=59428534087 4.25 Test the integrity of your filter by running tap water through your filter at a slow rate to identify any possible leaks in your filter and to clean the sand in the filter. Test the water exiting the water filter using the PathoScreen methodology. Report your results.

Solution If the filter has been assembled correctly the filter will not leak and water will be able to pass through the sand layer.

4.26 Walk to the nearest surface water source with a jerrican provided and collect water or use the untreated surface water provided. Test this water prior to filtering using the PathoScreen methodology. Report your results.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

4-14

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

Solution Answers will vary. See solution to Problem 4.24.

4.27 Collect or use the untreated surface water provided. Pour at least 8 L of the water through the filter. Time how long is required to obtain 8 L of filtered water. Discard the first 7 L of water collected from the exit of your sand filter. Collect the eighth liter of water and test this water exiting the filter using the PathoScreen methodology. Report your results in a written format and with a photo of the test tubes.

Solution Answers will vary. A true to size Biosand filter will likely remove pathogens; however, these are designed to simulate and illustrate how to design, assemble, and evaluate a product.

These filters, even if well designed, may not remove all pathogens due to the limited filter distance and residence time. The questions should be graded based upon the ability to follow procedural instructions and not the results of the test. See solution to Problem 4.24.

4.28 Describe the effectiveness of your filter design. Include in your analysis the total cost, average water filtration rate per hour, and the effectiveness of treatment based on the PathoScreen methodology.

Solution Answers will vary: Excellent

Good

Answers include correct cost calculations, equations and data reporting the filtration rate in appropriate units, and the treatment effectiveness of the filter describing in accurate language the quality of the filtrate

Answers include mostly correct cost calculations, equations and data reporting the filtration rate in appropriate units, and the treatment effectiveness of the filter describing in accurate language the quality of the filtrate

Needs Improvement One of the following may be inaccurate or poorly defined but the remaining descriptions include mostly correct cost calculations, equations and data reporting the filtration rate, and the treatment effectiveness of the filter

Poor

Unacceptable

Several of the following may be inaccurate or poorly defined but the remaining descriptions include cost calculations, equations and data reporting the filtration rate, and the treatment effectiveness of the filter

Several of the following may be missing, inaccurate, or poorly defined but the remaining descriptions including cost calculations, equations and data reporting the filtration rate, and the treatment effectiveness of the filter describing the filtrate

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

4-15

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 4: Sustainable Development Goals: Engineering for Environmental Sustainability

4.29 Would your simple filter design be appropriate and beneficial for use in a low-income country community? Explain your response based on technical, economic, social, and environmental factors.

Solution Answers may vary. An example of an excellent solution follows: The Biosand filter is appropriate for low-income communities. The filter requires minimal maintenance and no special tools. Short terms training is sufficient to construct and maintain the filter. A Biosand filter can last decades and can remove 100% of worms and worm eggs, 99.8% of protozoa, and 97-99% of bacteria. A household Biosand filter can hold 3 gallons of water and provide enough drinking water for a family. However, it is difficult to know if a Biosand filter has experienced break-through or failure without regular testing.

Useful resources: Centre for Affordable Water and Sanitation Technology (CAWST) What is a Biosand Filter: https://www.cawst.org/services/expertise/biosand-filter/moreinformation 4.30 Describe the requirements to operate and maintain the filter in the home. What training and materials would be needed to ensure that the system worked effectively for a period of five years?

Solution You need to clean your filter once a week.

1. Take off the lid.

2. Remove the diffuser.

3. Use soapy water to wash the diffuser and the lid, then rinse with previously filtered water.

4. Replace the diffuser and the lid.

5. Clean the outlet tube of the filter with chlorine (bleach). If chlorine is not available, use soap and water.

Useful resources: Centre for Affordable Water and Sanitation Technology (CAWST) Biosand Filter Use and Maintenance Videos: https://washresources.cawst.org/en/collections/dff54fff/biosand-filter-use-andmaintenance-videos?tab=2

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4-16

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

Chapter 5 Questions

5.1 Describe how the INCOSE, the International Council on Systems Engineering, defines a systems engineer.

Solution INCOSE describes a systems engineer as a transdisciplinary & integrative approach to enable the successful realization, use, and retirement of engineered systems, using systems principles and concepts, and scientific, technological, and management methods.

Resources: The International Council on Systems Engineering (INCOSE) is a not-for-profit membership organization founded to develop and disseminate the transdisciplinary principles and practices that enable the realization of successful systems. INCOSE is designed to connect systems engineering professionals with educational, networking, and career-advancement opportunities in the interest of developing the global community of systems engineers and systems approaches to problems. We are also focused on producing state-of-the-art work products that support and enhance this discipline’s visibility in the world. https://www.incose.org/ INCOSE - Think Engineer Systems Engineering is a transdisciplinary and integrative approach to enable the successful realization, use, and retirement of engineered systems, using systems principles and concepts, and scientific, technological, and management methods. https://youtu.be/EUAg3xJyQ9M

5.2 Find job listings for a systems engineering position. List the duties or the description of job tasks the employee would be expected to do for three advertised positions. You can find job listings through employment websites, USAJobs.gov, INCOSE.org, LinkedIn, Indeed.com, and other professional networking websites.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

Solution According to usajobs.gov, a systems engineer is tasked with “solicitation and utilizing the DHA for Certain Personnel of the DOD Workforce and appoint qualified candidates to positions in the competitive service.” This listing states duties generally include working to integrate systems, maintaining current systems, and working with officers and officials to complete projects.

Resources: The Systems Engineering Body of Knowledge (SEBoK) provides a guide to the key knowledge sources and references of systems engineering organized and explained to assist a wide variety of individuals. It is a living product, accepting community input continuously, with regular refreshes and updates. The SEBoK is not a compendium but instead references existing literature, and much of the content has restricted intellectual property rights. www.sebokwiki.org/wiki/Guide_to_the_Systems_Engineering_Body_of_Knowledge_(SEB oK) Systems Engineering Systems Engineers draw from many engineering disciplines and backgrounds and use an interdisciplinary approach to solving complex problems. Systems Engineers are involved in a wide variety of projects, from spacecraft and chip design, to creating large software projects and developing cutting edge technologies that can be applied to several domains. Systems Engineers often work in interdisciplinary teams with expertise on specific components such as electrical, software, or mechanical engineering. This video was created by Think TV with support from eTech Ohio. https://youtu.be/m3L9bEAha1I What Is Systems Engineering? | Systems Engineering, Part 1 This video covers what systems engineering is and why it’s useful. It presents a broad overview of how systems engineering helps us develop complex projects that meet the program objectives in an efficient way. This introduction will set the stage for the rest of the series which covers how system architectures are developed and described, how we communicate the needs, requirements, and constraints throughout the project, how we optimize the design through trade studies, and how we know the system does what it’s supposed to in the end. https://youtu.be/pSfZutP9H-U Towards a Model-Based Approach | Systems Engineering, Part 2 The role of systems engineering is to help find and maintain a balance between the stakeholder needs, the management needs, and the engineering needs of a project. So we can think of it as an optimization problem. This video covers how that optimization is done

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

by making good decisions over the course of the project. We can improve our chances that the decisions we make are actually good using trade studies and engineering experience. We also talk about how models play an important part in this whole process with model-based systems engineering (MBSE). https://youtu.be/bckHxdGjtQc The Benefits of Functional Architectures | Systems Engineering, Part 3 Functional, logical, and physical architectures are important tools for designing complex systems. We describe what architectures are and how they contribute to the early stages of a project. The focus of this video is on describing a system as a collection of its functions and we show how that can provide a foundation from which we can develop models and perform trade studies. https://youtu.be/UTm1ORuZ1dg An Introduction to Requirements | Systems Engineering, Part 4 Get an introduction to an important tool in systems engineering: requirements. You'll learn about the three things every requirement must have and what makes a requirement valid.

You'll also see how requirements and requirement hierarchies contribute to the system design process. https://youtu.be/Iblo2Il-pOA Some Benefits of Model-Based Systems Engineering | Systems Engineering, Part 5 Learn how model-based systems engineering (MBSE) can help you cut through the chaos of early systems development and get you from definition to execution more seamlessly. You’ll hear the transitional phase described in some detail to help you understand what drives the chaos and confusion. You’ll also see how MBSE can make reusing functions and components easier, how to perform interface and constraint verification, and how the model itself can become the implementation through code generation. https://youtu.be/ABtFFxxRWF4 5.3 List four physical processes and four biological processes that you interact with each day.

Solution Answer may vary. A sample answer is provided below: Physical processes may include traffic lights, air conditioning units, and dishwashers.

Chemical processes include plant life, and biological processes include eating, walking, and breathing.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.4 Create a box to represent two of the physical and two of the biological processes listed above that you interact with each day. Add to each box a process name, location, interactions between other processes, and the estimated quantity of material or energy involved in the process.

Solution Answer may vary. A sample answer is provided below:

5.5 Draw a schematic of the “you” system that shows how materials and energy flow around you in your daily life.

Solution Answer may vary. A sample answer is provided below:

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-4

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.6 What questions do you have about how the Chesapeake Bay system functions in relationship to the water quality, land use, fisheries, and people interacting with the bay environment?

Solution Answer may vary. A sample answer is provided below: What impact do people have on the bay and water quality? How do poor water quality and pollutants like nitrogen and phosphorus impact fisheries? What are positive things that can be done to improve water quality and fisheries in the Bay? Useful Resources: Founded in 1967, the Chesapeake Bay Foundation (CBF) is the largest independent conservation organization dedicated solely to saving the Bay. CFB fights for effective, science-based solutions to the pollution degrading the Chesapeake Bay and its rivers and streams. With offices in Maryland, Virginia, Pennsylvania, and the District of Columbia and 15 field centers, CBF leads the way in restoring the Bay and its rivers and streams. For more than 50 years, CBF has created broad understanding of the Bay's poor health, engaged public leaders in making commitments to restore the Chesapeake, and fought successfully to create a new approach to cleanup that features real accountability—the Chesapeake Clean Water Blueprint.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-5

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

Chesapeake Bay Foundation: https://www.cbf.org/ EPA Restoration of the Chesapeake Bay: https://www.epa.gov/restoration-chesapeakebay NOAA: Fisheries: Chesapeake Bay: The Bay is a highly valued resource for the region for additional reasons, including tourism, recreational boating, and scenic beauty. In recent decades, the Bay’s biologically diverse ecosystem has seen sharp declines in some of its keystone species, including the native oyster. Human effects on the ecosystem, like overfishing, degraded water quality, and habitat destruction, are significant challenges to the Chesapeake and the species that live there. We work to improve the health of the Bay by using the latest science to ensure its sustainable use for generations to come.

NOAA – Chesapeake Bay: https://www.fisheries.noaa.gov/topic/chesapeake-bay US Fish and Wildlife Service: Chesapeake Bay Ecological Services Field Office: https://www.fws.gov/office/chesapeake-bay-ecological-services USGS - Chesapeake Bay Activities: https://www.usgs.gov/centers/chesapeake-bayactivities Cleaning Up The Chesapeake In this video, researchers study ways to reduce pollutants in runoff; others examine effects of pollution on fish and oysters in the Chesapeake Bay. https://youtu.be/GfecQBuIdOA 5.7 What one question would you most like to explore and learn more about regarding the Chesapeake Bay system?

Solution Answer may vary. A sample answer for the oyster harvest question is provided below: One thing I would like to explore about the Chesapeake Bay is how oyster harvest impacts the overall health of the Bay. I specifically chose this question because it has been given a grade of “F” on the Bay Report Card.

5.8 Describe what steps you can take to explore your curiosity. How would you find out more information related to Problem 5.7?

Solution Answer may vary. A sample answer is provided below: • •

Textbooks Websites

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-6

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

• • • • • •

Library Articles Newspapers and other news reporting services Journal Articles Not for profit organization reports and meetings In-person visits Governmental agencies and personnel

Excellent

Good

Answers correctly list a variety of resources, both peer reviewed sources, science sources, and general sources

Answers correctly list a smaller group of diverse resources, including peer reviewed sources and government agencies

Needs Improvement Answers correctly list a small group of resources, including at least one mention of peer reviewed sources or government agencies

Poor

Unacceptable

Answers incorrectly list some resources and omits peer reviewed sources or government agencies

Answers list two or less resources and omit peer reviewed sources or government agencies

5.9 List the potential sources of information that might help you learn more about your above question (see Problem 5.7). Also list where you might find this information (e.g., the library, a specific website, an educational organization).

Solution Answers may vary, but more specific detail is needed than supplied. A sample answer is provided below: •

• • • •

Websites o Chesapeake Bay Foundation: https://www.cbf.org/ o EPA Restoration of the Chesapeake Bay: https://www.epa.gov/restorationchesapeake-bay o NOAA – Chesapeake Bay: https://www.fisheries.noaa.gov/topic/chesapeake-bay o US Fish and Wildlife Service: Chesapeake Bay Ecological Services Field Office: https://www.fws.gov/office/chesapeake-bay-ecological-services o USGS - Chesapeake Bay Activities: https://www.usgs.gov/centers/chesapeake-bay-activities o And so on…

Library Articles Newspapers and other news reporting services Journal Articles Not for profit organization reports and meetings

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-7

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

• •

In-person visits Governmental agencies and personnel

Excellent

Good

Answers correctly list a variety of specific resources and methods to find relevant peer reviewed sources, science sources, and general sources

Answers correctly list a smaller group of specific resources and search tools, including some peer reviewed sources and government agencies

Needs Improvement Answers correctly list a small group of resources and web-based search including at least one mention of peer reviewed sources or government agencies

Poor

Unacceptable

Answers incorrectly list some resources and omits peer reviewed sources or government agencies

Answers only list resources and omits the methods used to find resources and peer reviewed sources or government agencies

5.10 What are characteristics of “good” or “reliable” information? How would you interpret and prioritize various sources of information from more reliable to less reliable?

Solution Answer may vary.

Excellent

Good

Answers correctly describe relevant peer reviewed sources, science sources, and distinguishes the difference between nonscience sources

Answers correctly describe relevant peer reviewed sources, science sources, but do not distinguish between nonscience sources

Needs Improvement Answers partially describe relevant peer reviewed sources, science sources, but do not distinguish between nonscience sources

Poor

Unacceptable

Answers may incorrectly interpret the difference between relevant peer reviewed sources and non-science sources

Answers make no distinction between relevant peer reviewed sources and non-science sources

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-8

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.11 List a comprehensive set of key words related to your area of interest. You will later use these key words to search sources for information that helps describe how the Chesapeake Bay system functions.

Solution Answer may vary.

Excellent

Good

More than 15 keywords correctly describing relevant processes

More than 10 keywords correctly describing relevant processes

Needs Improvement More than 6 keywords correctly describing relevant processes and other somewhat relevant keywords are present

Poor

Unacceptable

Only a few keywords correctly describe relevant processes and other somewhat relevant keywords are present

Keywords are only somewhat relevant

A sample answer for the oyster harvest question is provided below: Oyster fisheries, oyster function, oyster benefits, history of oysters in the Bay, importance of oysters in the Bay, impact of oysters in the Bay, Bay fisheries, function of fisheries in the Bay, impacts of different species in the Bay, osier restoration, biodiversity, oyster health, oyster habitat, oyster habitat destruction 5.12 In this step, draw a picture or sketch that represents the system you are curious about.

Sketch processes within the system and define boundaries for a system that encompasses your idea. Later, you will refine your sketch, so this sketch should be done by brainstorming and visually representing your ideas and things you think might be connected to your topic of interest.

Solution Answer may vary.

Excellent

Good

The sketch correctly illustrates system flows, the system boundary, and

The sketch shows system flows, the system boundary, and

Needs Improvement The sketch clearly shows system flows, the system boundary, and labels flows and

Poor

Unacceptable

The sketch does not clearly show system flows, the system boundary, and

The sketch does not show system flows, the system boundary, or labels and is

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-9

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

labels all relevant flows and repositories.

The sketch is clear and concise

labels flows and repositories

repositories but is missing some important information

labels flows and repositories and is missing some important information

missing much important information

An ”excellent” sample answer for the oyster harvest question is provided below:

Resources: The Chesapeake Bay Regional Estuarine Ecosystem Model. (CBREEM) was developed to create a nutrient-loading index that could be used to drive primary productivity in the Chesapeake Bay Fisheries Ecosystem Model (CBFEM). The model uses historical data for climate, hydrology, and nutrient loading to estimate patterns in primary productivity for the Chesapeake Bay. This model integrates information about the estuary’s physical, chemical, and ecological processes into key indicators that environmental managers can use to predict temporal and spatial changes in the Bay. Results from CBREEM can be used to look at nutrient management strategies and might be used to manage fisheries by connecting it to CBFEM. https://www.chesapeakebay.net/what/programs/modeling Chesapeake Bay Fisheries Ecosystem Model: The Chesapeake Bay Fisheries Ecosystem Model (CBFEM) is an exploratory tool that helps scientists and others understand the Chesapeake Bay ecosystem. Explorations using CBFEM have focused on interactions between menhaden and striped bass (and other predators), potential effects of hypoxia on fisheries species, and the habitat-mediation effects of submerged aquatic vegetation on blue crab stocks. https://spo.nmfs.noaa.gov/sites/default/files/TM106%20FINAL.pdf Chesapeake Community Modeling Program: CCMP is dedicated to advancing the cause of accessible, open-source environmental models of the Chesapeake Bay in support of research & management efforts. Through communication and advocacy, the CCMP has generated several new modeling-oriented research programs. Our new web pages will help by providing access to Chesapeake community models and data. Funded through base © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-10

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

support from NOAA’s Chesapeake Bay OfficeLinks to an external site. and access to the US EPA Chesapeake Bay Program server, CCMP continues to expand model and data access for the regional community. http://ches.communitymodeling.org/index.php 5.13 Draw a black box process that illustrates one part of your system of Chesapeake Bay sketched in Problem 5.12.

Solution Answer may vary.

Excellent

Good

The figure correctly illustrates detailed system flows, the system boundary, and labels all relevant flows and repositories.

The sketch is clear and concise

The figure illustrates most relevant system flows, the system boundary, and labels flows and repositories

Needs Improvement The figure illustrates some system flows, the system boundary, and labels flow and repositories but is missing some important information

Poor

Unacceptable

The figure does not clearly show system flows, the system boundary, and labels flows and repositories and is missing some important information

The figure does not show system flows, the system boundary, or labels and is missing much important information

A sample answer for the oyster harvest question is provided below:

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-11

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.14 Define your process(es) as splitting, mixing, reactions, and so on and show the material flow and/or energy flow streams entering and exiting your process(es).

Solution Answer may vary.

Excellent

Good

The figure correctly illustrates important system flows, the system boundary, and labels all relevant flows and repositories.

The sketch is clear and concise. The drawing can be used to mathematically model a simplified version of the system.

The figure illustrates most relevant system flows, the system boundary, and labels flows and repositories.

The drawing can be used to mathematically model a simplified version of the system with minor modifications.

Needs Improvement The figure illustrates some system flows, the system boundary, and labels flow and repositories but is missing some important information.

The drawing can be used to mathematically model a simplified version of the system with major modifications.

Poor

Unacceptable

The figure does not clearly show system flows, the system boundary, and labels flows and repositories and is missing some important information.

The drawing cannot be used to mathematically model a simplified version of the system.

The figure does not show system flows, the system boundary, or labels and is missing much important information.

The drawing is irrelevant for developing a mathematically model of the system.

A sample answer for the oyster harvest question is provided below:

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-12

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.15 Create a list of mathematical variables associated with each flow in the Chesapeake Bay process(es) you defined in the model developed in Problem 5.13.

Solution Answer may vary.

Excellent

Good

The variables define the important system flows and repositories.

The variables can be used to mathematically model a simplified version of the system.

The variables define most of the important system flows and repositories.

The variables can be used to mathematically model a simplified version of the system with minor modifications.

Needs Improvement The variables define some of the important system flows and repositories.

The variables can be used to mathematically model a simplified version of the system with major modifications.

Poor

Unacceptable

The variable list does not clearly identify flows and repositories and is missing some important information.

The variables are insufficient to mathematically model a simplified version of the system.

The variable list does not identify system flows or labels and is missing much important information.

The variables are irrelevant for developing a mathematical model of the system.

A sample answer for the oyster harvest question is provided below: • •

Rate of water filtered by an oyster Rate of phosphorus removed by an oyster

5.16 Determine the number of variables you will need from the list of variables created in Problem 5.15 to define and properly constrain the process(es) in your system.

Solution Answer may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-13

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.17 Develop a mathematical model, similar to the system described in Example 5.1, for the Chesapeake Bay process you have modeled in Problem 5.13. Define the relevant mathematical relationships and variables.

• Use peer-reviewed sources or other documented sources to determine values for as many of your controlled variables and uncontrolled variables as possible. (Note: this may over-constrain your system.) Consider starting your search with textbooks, journal articles, government documents, CBF reports, or other resources as appropriate.

• List the variables and reference for the sources of your information; a range of data for a given variable is appropriate.

Solution Answer may vary.

Excellent

Good

Most of the variable values are provided based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation.

Variables and equations are correctly used to represent a simplified version of the system. There are enough equations to describe the simplified system.

Many of the variable values are provided based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation.

Variables and equations are generally correctly used to represent a simplified version of the system. There are nearly enough equations to describe the simplified system.

Needs Improvement Some of the variable values are provided based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation. The equations represent the first step in describing the simplified system.

Poor

Unacceptable

Variable values are not based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation. The equations do not represent the system.

Variable values are not based on peerreviewed data or collected via the scientific method.

Equations are not based upon the general mass balance equation. The equations do not represent the system.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-14

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

A sample answer for the oyster harvest question is provided below: 𝑄𝑄𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 𝑖𝑖𝑖𝑖 × 𝐶𝐶𝑃𝑃ℎ𝑜𝑜𝑜𝑜𝑜𝑜ℎ𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 = 𝑄𝑄𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 𝑜𝑜𝑜𝑜𝑜𝑜 × 𝐶𝐶𝑃𝑃ℎ𝑜𝑜𝑜𝑜𝑜𝑜ℎ𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 + 𝑀𝑀𝑃𝑃ℎ𝑜𝑜𝑜𝑜𝑜𝑜ℎ𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜 𝑠𝑠𝑠𝑠𝑠𝑠𝑟𝑟𝑒𝑒𝑒𝑒

Where • Qwater in = Water entering the oyster • Qwater out = water exiting the oyster • CPhosphorous in = concentration of phosphorous entering the oyster • CPhosphorous out = concentration of phosphorous in water exiting the oyster • Mphosphorous stored = mass rate of phosphorous removal by the oyster • Water filtered by an oyster = 30-60 gal/day (avg. of 50 gal/day) o https://www.sarasota.wateratlas.usf.edu/oysters/?section=Oysters%20 and%20Water%20Quality • Phosphorus filtered by an oyster = 22-154 lbs of phosphorus per 1 million oysters (use this to figure out rate) o https://www.aquaculturenorthamerica.com/oysters-play-role-inimproving-water-quality-1409/

5.18 Use your system-level sketch from Problem 5.12 to create a representation of another process connected to the process described in Problem 5.17 of your Chesapeake Bay system.

Solution Answer may vary.

Excellent

Good

The figure correctly illustrates important system flows, the system boundary, and labels all relevant flows and repositories.

The sketch is clear and concise. The drawing can be used to mathematically model a simplified

The figure illustrates most relevant system flows, the system boundary, and labels flows and repositories.

The drawing can be used to mathematically model a simplified version of the system with minor modifications.

Needs Improvement The figure illustrates some system flows, the system boundary, and labels flow and repositories but is missing some important information.

The drawing can be used to mathematically model a simplified version of the system with major modifications.

Poor

Unacceptable

The figure does not clearly show system flows, the system boundary, and labels flows and repositories and is missing some important information.

The drawing cannot used to mathematically model a simplified

The figure does not show system flows, the system boundary, or labels and is missing much important information.

The drawing is irrelevant for developing a mathematically model of the system.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-15

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

version of the system.

version of the system.

A sample answer for the oyster harvest question is provided below:

5.19 Create a list of mathematical variables associated with each flow in the Chesapeake Bay process(es) you defined in Problem 5.18 above.

Solution Answer may vary.

Excellent

Good

The variables define the important system flows and repositories.

The variables can be used to mathematically model a simplified version of the system

The variables define most of the important system flows and repositories.

The variables can be used to mathematically model a simplified version of the system with minor modifications

Needs Improvement The variables define some of the important system flows and repositories.

The variables can be used to mathematically model a simplified version of the system with major modifications

Poor

Unacceptable

The variable list does not clearly identify flows and repositories and is missing some important information.

The variables are insufficient to mathematically model a simplified version of the system.

The variable list does not identify system flows or labels and is missing much important information.

The variables are irrelevant for developing a mathematical model of the system.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-16

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

A sample answer for the oyster harvest question is provided below: • • • • •

Concentration of phosphorus entering the wastewater treatment plant Water flowrate into wastewater treatment plant Concentration of phosphorus exiting the wastewater treatment plant Rate of water filtered by an oyster Rate of phosphorus removed by an oyster

5.20 Describe each variable listed in Problem 5.19, research each variable, and provide ranges for reported values. Report the values and expected ranges (high, mean, and low values if available). Provide a citation for the source of information for each of the values you find.

Solution Answer may vary.

Excellent

Good

Most of the variable values are provided based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation.

Variables and equations are correctly used to represent a simplified version of the system. There are enough equations to describe the simplified system.

Many of the variable values are provided based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation.

Variables and equations are generally correctly used to represent a simplified version of the system. There are nearly enough equations to describe the

Needs Improvement Some of the variable values are provided based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation. The equations represent the first step in describing the simplified system.

Poor

Unacceptable

Variable values are not based on peerreviewed data or collected via the scientific method.

Equations for the rate of change are based upon the general mass balance equation. The equations do not represent the system.

Variable values are not based on peerreviewed data or collected via the scientific method.

Equations are not based upon the general mass balance equation. The equations do not represent the system.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-17

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

simplified system.

A sample answer for the oyster harvest question is provided below: •

•

•

•

•

Concentration of phosphorus in wastewater = 5-20 mg/L o https://www.lentech.com/phosphorusremoval.htm#:~text=Phosphorous%20in%20wastewater,main%20consititu ent%20of%20syntheic%20detergents Water going into wastewater treatment plant = amount of wastewater treatment plant = 1000 – 10000 tons/day o https://www.nature.com/articles/s41598-019-50952-0 Phosphorus going out of wastewater treatment plant (Chesapeake Bay area specifically) = 0-0.3 mg/L o https://www.chesapeakebay.net/issues/threats-to-thebay/wastewater#:~:text=Wastewater%20treated%20at%20facilities%20usi ng%20ENR%20contains%203%20milligrams%20per,milligrams%20per%20lit er%20of%20phosphorus Water filtered by an oyster = 30-60 gal/day (avg. of 50 gal/day) o https://www.sarasota.wateratlas.usf.edu/oysters/?section=Oysters%20and %20Water%20Quality Phosphorus filtered by an oyster = 22-154 lbs of phosphorus per 1 million oysters (use this to figure out rate) o • https://www.aquaculturenorthamerica.com/oysters-play-role-inimproving-water-quality-1409/

For concentration of phosphorus in wastewater, we want to consider that it comes from human waste, food, and certain soaps and detergents. From this, it is determined that municipal wastewaters may contain 5-20 mg/L of phosphorus based on location and when processed in wastewater treatment plants, removal rates result of phosphorus from different methods of removal, biological or enhanced nutrient removal, are used to determine the rate of phosphorus coming out of the plant. The water flow in and out of the plant is the same since all the water is filtered and this is found from a national average range of 1,000 to 10,000 tons/day. Finally, to determine how much water a single oyster can filter, we need to determine how much water a single oyster can filter each day where on average, it is around 50 gal/day for most, but it can range from 30-60 gal/day. Then the amount of phosphorus stored in the tissues of oysters can be used to find the concertation of phosphorus left in the water. All these values can then be used to find the remaining water flow and phosphorus in the Bay. 5.21 For any unknown variables for which you could not find values reported in the scientific literature, define key words for research studies that might provide information about the unknown variables.

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5-18

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

Solution Answer may vary.

Excellent

Good

More than 9 keywords correctly describing relevant processes

More than 6 keywords correctly describing relevant processes

Needs Improvement More than 3 keywords correctly describing relevant processes and other somewhat relevant keywords are present

Poor

Unacceptable

Only a few keywords correctly describe relevant processes and other somewhat relevant keywords are present

Keywords are only somewhat relevant

A sample answer for the oyster harvest question is provided below: The only unknown variable that I was unable to find is the concentration of phosphorus in the water filtered out by oysters. I was able to find how much phosphorus is stored in the tissues of oysters. This can be used to figure out the amount of phosphorus in a single oyster and then used to find the concertation by mass balance. However, key words such as “percentage” and “rates” can be used to find the percent of phosphorus filtered which can then be used to find the concentration as well. The remaining unknown values are what will be calculated/ what needs to be found using the other researched ranges.

5.22 Describe a system similar to the ones you have chosen to investigate. How might similar systems be studied to help guide any reasonable assumptions you might be able to make in an analysis?

Solution Answer may vary.

A sample answer for the oyster harvest question is provided below: Some similar systems could be looking at how nitrogen, sediments, or toxins are filtered by oysters from either the same source at the wastewater treatment plant or other sources such as agricultural runoff, air pollution, and waste being directly deposited into the Bay through mediums such as ships. Another system that can be looked at is more general pollution rates filtered out/impacted by oysters. This is because this system can give insight into how oysters impact overall rates of pollution as their population declines or inclines.

This is an important aspect because phosphorus is one of the many pollutants decreasing the quality and health of the Chesapeake Bay and its ecosystems. Another system that one

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-19

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

can look at is the nitrogen or phosphors utilization in different kinds of agricultural fields.

Not only will this give more insight into how rates of agricultural runoff with certain nutrient concentrations are determined, but it also has a similar set up of looking at the concertation of nutrients going in and using rates of removal to figure out what is left over.

5.23 Describe the boundary conditions of your system and the inherent assumptions required to mathematically define a mathematical model of the system you have described above.

Solution Answer may vary.

A sample answer for the oyster harvest question is provided below: The boundary conditions of the system are strictly looking at how wastewater with phosphorus is processed by wastewater treatment and then how that is processed by oysters. From research, as well as maintaining simplicity, we set boundary conditions to looking at one oyster which filters 50 gallons of water per day (most common rate of filtration). Additionally, higher ranges will be used to figure out maximum values.

5.24 What related conditions beyond the boundary you defined in Problem 5.18 might impact an analysis of the system? For example, these conditions may be assumptions about the size, shape, environmental conditions, connected flows, or other features of the system you have described. Illustrate these potential conditions and impacts by revising the schematic from Problem 5.18.

Solution Answer may vary.

A sample answer for the oyster harvest question is provided below: The boundary of the system focuses very simply (or, in ways, is limited to) one wastewater plant and one oyster. It does not consider all of the other wastewater treatment plants or oyster contributions to the system. It also does not consider other pollutant sources such as industrial/agricultural runoff, air pollution, and existing water pollution. Additionally, other elements of filtration are not taken into account.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-20

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.25 Synthesize and apply systems thinking, principles, and tools to complex systems. Sketch the information requested below as a mind map or similar illustration. The goal is to expand the knowledge about activities in the Chesapeake Bay watershed and illustrate the connection between those activities or processes. You will be asked to peer-review another student’s system sketch. The feedback from your peers should be used to improve your individual work on reflection, communication, and refinement of the model you developed in Problems 5.18 through 5.24. Identify how your black box model is linked to five other black boxes being developed by peers in the class. You must speak to more than five different people to find five systems that share a well-defined link.

• Redraw the boundary conditions for your related processes.

• Show all the systems the student interacted with in class in each drawing; some may be linked, while some may not be.

• For each system, define all possible variables that relate to each individual system and identify the names of the class peers related to each system.

• Illustrate the variables being analyzed through others’ system interactions.

• Illustrate the variables that have been ignored by choice in the interacting systems.

Solution Answer may vary.

Excellent

Good

The sketch correctly illustrates system flows, the system boundary, and labels all relevant flows and repositories.

The sketch is clear and concise

The sketch shows system flows, the system boundary, and labels flows and repositories

Needs Improvement The sketch clearly shows system flows, the system boundary, and labels flows and repositories but is missing some important information

Poor

Unacceptable

The sketch does not clearly show system flows, the system boundary, and labels flows and repositories and is missing some important information

The sketch does not show system flows, the system boundary, or labels and is missing much important information

A sample answer for the oyster harvest question is provided below:

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-21

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.26 Update the schematic you developed in Problem 5.24 with new information developed from your networking discussion.

• Identify by name the source of information for the linked black boxes—this creates a new system.

• Identify known and unknown variables in the system and changes throughout the system of study. Note: This may require additional interactions beyond classroom time, so you might benefit from seeking permission to contact your classmates outside of the normal class period.

Solution Answer may vary.

Excellent

Good

The figure correctly illustrates important system flows, the system boundary, and labels all

The figure illustrates most relevant system flows, the system boundary, and labels flows and repositories.

Needs Improvement The figure illustrates some system flows, the system boundary, and labels flow and repositories but is missing some

Poor

Unacceptable

The figure does not clearly show system flows, the system boundary, and labels flows and

The figure does not show system flows, the system boundary, or labels and is missing much important

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-22

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

relevant flows and repositories.

The sketch is clear and concise. The drawing can be used to mathematically model a simplified version of the system.

The drawing can be used to mathematically model a simplified version of the system with minor modifications.

important information.

The drawing can be used to mathematically model a simplified version of the system with major modifications.

repositories and is missing some important information.

The drawing cannot used to mathematically model a simplified version of the system.

information.

The drawing is irrelevant for developing a mathematically model of the system.

A sample answer for the oyster harvest question is provided below:

5.27 Identify and evaluate trade-offs to make informed decisions about managing resources in the Chesapeake Bay watershed. Is the question you started with in Problem 5.7 the question for which you developed an analytical model? Describe how your thinking about the problem changed throughout the process of developing a model for the system.

Solution Answer may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-23

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 5: Food, Water, and Nutrients in Chesapeake Bay: An Earth Systems Engineering Approach

5.28 What are the key elements or key words that were most useful in searching for data related to your analytical model development?

Solution Answer may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

5-24

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

Chapter 6 Questions

6.1 Of all the products you have used recently, which do you consider your favorite? List all the reasons that make that product your favorite product.

Solution Sample solution: answers may vary.

Water bottle, sunscreen, car, sweatpants, phone, TV, chopsticks, toothbrush, lotion. I consider my water bottle to be my favorite item I use regularly. This is because of the sleek design and its ability to carry water so that I may be able to carry water with me through the day and stay hydrated.

6.2 Of all the products you have used recently, which do you consider your least favorite? List all the reasons that make that product your least favorite product.

Solution Sample solution: answers may vary.

Blankets, laptop, pencil, fork, tote bag, phone. I consider my blanket to be my least favorite product because the material is too thin, the fabric is not comfortable enough, and there is not enough length to fully cover my body to keep it warm.

6.3 Look up and draw the schematic of various phases of the engineering design process (www.teachengineering.org/populartopics/designprocess).

Solution

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.4 Look up and draw the schematic of various phases of the human-centered design process as prescribed by IDEO (www.ideo.org/tools).

Solution

6.5 Look up and draw the schematic of the various phases of the Stanford d-school’s design thinking process (www.empathizeit.com/design-thinking-models-stanford-d-school/).

Solution

6.6 Write down the similarities and differences you observed after comparing (1) the engineering design process, (2) IDEO’s human-centered design process, and (3) Stanford dschool’s design thinking process.

Solution Sample solution: answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

Similarities include containing a testing stage, an imagining or brainstorming stage, the use of colors, a simplistic design, and a simple description of each stage. Differences include a different number of stages, a lack of description, questions, and design style.

6.7 Write down the initial problem statement based on your understanding of the design prompt. The problem statement must include the current undesirable state and desired goal state.

Solution Sample solution: answers may vary.

Most book bags are bulky, they don’t reach a variety of aesthetics and are visually unappealing and are uncomfortable to wear. Engineers are tasked with addressing these issues to create a product that is as aesthetically pleasing as possible and functions for long term use.

6.8 Identify potential users. This could be an individual who will either pay for or use your final product.

Solution Sample solution: answers may vary.

College students, grade school students and parents, and people living in cites or constantly on the move.

6.9 List five to seven questions that you would want to ask the user during the interview.

Remember to frame open-ended questions that will allow you to gather the pain points, likes, and dislikes of the user.

Solution Sample solution: answers may vary.

1. What is one thing you like/dislike about your current backpack?

2. What would you like to see in a new backpack?

3. Why do you carry a backpack?

4. What is one thing you would change about your current backpack?

5. How often and for how long do you carry your backpack?

6. How does your backpack affect your back?

6.10 Jot down the notes from the interview. If you conduct multiple interviews, jot down the notes for each interview separately. Look for similarities and differences and capture the likes and dislikes for all users you interviewed.

Solution Sample solution: answers may vary.

I refers waterproof designs, I don’t like large designs for my bags, my backpack makes my back hurt, I would like more variety in design like neutral colors, I wear my backpack 7 day a week for 1-5 hours a day. Similarities include wanting more comfortable backpack options and differences include pocket preferences.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.11 Based on the notes gathered during the interview(s), write down an updated problem statement to reflect the needs of the user.

Solution Sample solution: answers may vary.

The user struggles with back and shoulder pain caused by backpacks and lack of storage while carrying the backpack throughout their day. Engineers are tasked with creating a backpack that provides the user with maximum comfort and storage while providing a chic design that is suitable for different weather conditions.

6.12 Based on the notes gathered during the interview(s), list at least 10 requirements.

Solution Sample solution: answers may vary.

1. The book bag must be waterproof.

2. The book bag must be comfortable to wear for many hours.

3. The book bag must be able to accommodate different body types.

4. The book bag must come in a variety of sizes.

5. The book bag must come in a variety of styles including a neutral style range.

6. The book bag must have more back and shoulder padding.

7. The book bag must contain 1-2 large storage compartments.

8. The book bag must have adjustable water bottle holders.

9. The book bag must have a variety of sized smaller compartments (4 max).

10. The book bag must be made of sustainable materials for long wear.

6.13 Using brainstorming as a method to generate concepts, generate and document (as either a sketch or a written description) at least 20 unique concepts for the futuristic book bag.

Solution Sample solution: answers may vary.

Note: image does not include 20 concepts.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-4

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.14 From the concepts generated in Problem 6.13, select the top eight and sketch them out in more detail below. You may also consider including a brief description (2-3 sentences) for each concept.

Solution Sample solution: answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-5

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.15 From the 8 concepts developed in more detail in Problem 6.14, gather some feedback from the users and narrow the list down to 4 concepts. Perform concept evaluations and selection by comparing each of the 4 remaining concepts against the 10 requirements developed in Problem 6.10. Use a ranking scale of 1-5, where 1 = does not meet the requirements and 5 = fully meets the requirements. At the end of this activity, select the top 2 concepts for the next design phase.

Solution Sample solution: answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-6

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.16 Clearly sketch and describe the top two concepts as identified in Problem 6.15 based on the scores.

Solution Sample solution: answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-7

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.17 For each of your top 2 concepts, list the materials you plan to use for making initial prototypes.

Solution Sample solution: answers may vary.

Materials may include memory foam, elastic, cotton, cloth, nylon fabric, thread, etc.

6.18 For each of your top two concepts, list the processes or manufacturing techniques needed to make an initial prototype. Examples include three-dimensional printing, sewing, woodworking, and so on.

Solution Sample solution: answers may vary.

Special techniques will include sewing. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-8

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.19 Build a prototype of each of your top 2 concepts in a way that a potential user can interact with and provide feedback to. Write down the feedback you got from the users for each of the two prototypes.

Solution Sample solution: answers may vary.

Prototype 1 got feedback that the user enjoyed the shape and size of the pockets, but the overall design felt small. For prototype 2, user feedback conveyed the size was ideal for the front pocket and enjoyed the amount of padding and internal support of the bag.

6.20 What design decisions might you make based on the feedback you got for your prototypes?

Will you change anything in your design? If yes, what and why? If no, why not?

Solution Sample solution: answers may vary.

Design decisions include keeping the memory foam padding and changing the front pocket to be long and deep rather than one or the other. This change would be made because the user expressed preference in this component in both designs.

6.21 Draw a detailed hand-drawn sketch of your final book bag design with all major dimensions labeled.

Solution Sample solution: answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-9

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

6.22 Research and identify the materials you would like to use for the final book bag design.

Justify your decision of selecting these particular materials.

Solution Sample solution: answers may vary.

Nylon would be used in order to adhere to the waterproof design, memory foam would be used in order to create the internal padding, elastic would be used in order to create the elastic water bottle holder, and zippers and tracks would be used as well to add the ability to seal the bag.

6.23 Research and identify some manufacturing processes you might need to use to make the final book bag design. List them below.

Solution Sample solution: answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-10

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 6: Approaches to Engineering Design

The nylon fabric would need to be sized and cut in order to properly adhere to the dimensions of the bag. Sewing would be used to attach the water bottle holder, zipper, pocket, straps, buckles, and main body together.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

6-11

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

Chapter 7 Questions 7.1. Describe how the U.S. Bureau of Labor and Statistics defines a mechanical engineer, the entry-level education required, and the median salary for mechanical engineers by reviewing the Field of Degree highlights for students and job seekers in the Occupational Outlook Handbook.

Solution According to The U.S. Bureau of Labor and Statistics, Mechanical engineers “Perform engineering duties in planning and designing tools, engines, machines, and other mechanically functioning equipment. Oversee installation, operation, maintenance, and repair of equipment such as centralized heat, gas, water, and steam systems.” From the US Bureau of Labor and Statistics.

Median salary of $95,300 7.2. Describe how the U.S. Bureau of Labor and Statistics defines a petroleum engineer, the entry-level education required, and the median salary for a petroleum engineer by reviewing the Field of Degree highlights for students and job seekers in the Occupational Outlook Handbook.

Solution According to The U.S. Bureau of Labor and Statistics, petroleum engineers “Devise methods to improve oil and gas extraction and production and determine the need for new or modified tool designs. Oversee drilling and offer technical advice.” From the US Bureau of Labor and Statistics.

Median Salary of $130,850 7.3. Find job listings for a mechanical engineering position, a petroleum engineering position, or a nuclear engineering position. Describe the similarities and difference between the education required, experience required, and salary range (if available) for two different positions. What other educational degrees or requirements would be acceptable for the job listing you have found? You can find job listings through employment websites, USAJobs.gov, ASME.org, LinkedIn, and other professional networking websites.

Solution Answers may vary.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

7-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

Excellent

Good

Answers correctly describe education required, experience required, and salary range (if available) for two or more positions in the fields of mechanical, petroleum, and nuclear engineering.

Numerical salary information is provided, and multiple job descriptions are properly referenced.

Answers correctly describe education required, experience required, and salary range (if available) for positions in the fields of mechanical, petroleum, and nuclear engineering.

Numerical salary information is provided.

Needs Improvement Answers mostly describe education required, experience required, and salary for at least two positions in the fields of mechanical, petroleum, and nuclear engineering.

Poor

Unacceptable

Answers partially describe education required, experience required, and salary for at least one position in the fields of mechanical, petroleum, and nuclear engineering.

Answers misidentify education required, experience required, and salary for at least positions in the fields of mechanical, petroleum, and nuclear engineering.

An example solution is shown: Education Requirements: ● Mechanical engineers typically need a bachelor's degree in mechanical engineering or a related field. ● Petroleum engineers typically need a bachelor's degree in petroleum engineering, chemical engineering, or a related field. ● Nuclear engineers typically need a bachelor's degree in nuclear engineering, mechanical engineering, or a related field.

Experience Requirements: ● Mechanical engineers may need several years of work experience in mechanical design or related areas. ● Petroleum engineers may need several years of experience working in the oil and gas industry. ● Nuclear engineers may need experience in nuclear power plants or other related areas.

Salary: ● Salaries can vary widely depending on the job, location, and company. ● According to the U.S. Bureau of Labor Statistics, the median annual wage for mechanical engineers was $88,430, as of May 2020. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

7-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

● ●

The median annual wage for petroleum engineers was $137,720, as of May 2020.

The median annual wage for nuclear engineers was $115,220, as of May 2020.

7.4. Estimate how much energy you use each day. a. From your mileage traveled by car, motorcycle, or public transportation and your apartment or home energy bill (or a sample energy bill provided by the instructor), determine the amount of kilowatt-hours of energy used on average each month.

Solution Solutions may vary. Example solutions are listed below: Electricity usage: 11,319 kWh/year ×

Natural gas usage:

66,000 ft 3 /yr ×

Home gasoline use:

464 gallons ×

Home fuel oil use:

1 year = 943 kWh/month 12 months

1031 Btu kWh yr × × �12 month = 1662 kWh/month ft 3 3412 Btu

kWh 125,000 Btu yr × × �12 month = 1417 kWh/month 3412 Btu gallon

551 gallons ×

138,690 Btu gallon

×

kWh

3412 Btu

Gasoline for automobile transportation: 11,319 miles car

×

gallon

21.5 miles

×

125,000 Btu gallon

×

×

kWh

yr �12 month = 1866 kWh/month

3412 Btu

×

yr �12 month = 1607 kWh/month

b. Show the list of transportation, industrial use, residential use, and electric power consumption in a bar or pie chart.

Solution Solutions may vary. An example solution is shown below:

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

7-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

c.

Determine from your regional energy provider the source of your energy: coal, natural gas, petroleum, renewable energy, nuclear, and so on. Visit spotforcleanenergy.org for your regional energy portfolio. Show the portfolio of energy used by source in a bar or pie chart.

Solution Answers may vary. An example solution for the State of Virginia is shown:

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

d. How closely did your graph estimates match the sources of energy in your state?

Solution Answers may vary. e. From the Gap Analysis on the State Policy Opportunity Tracker (SPOT) for clean energy, list three to five energy market opportunities for which your state is best prepared for its energy future and list three to five energy market opportunities for which your state is least prepared for its energy future. Briefly summarize why your state is well prepared for some energy opportunities and much less prepared for other energy opportunities.

Solution Solutions may vary. An example solution is shown below:

Virginia is Best Prepared for: Interconnection Energy Savings Performance Contracting State Energy/Climate Plan Energy Storage Standards Commercial Property Assessed Clean Energy Virginia is Least Prepared for: Vehicle Charging Infrastructure Incentives New Utility Business Model Proceeding

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7-5

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

Customer Data Access Distributed Generation/Solar Carve-out Renewable Standard Offer On-Bill Financing / On-Bill Repayment Green/Infrastructure Bank 7.5. Describe the technological and engineering changes that resulted in changes to the sources of energy used in the United States during each century listed below. The resources at the U.S. Energy History Visualization project (https://us-sankey.rcc.uchicago.edu) may be helpful in your analysis. The interactive visualization shows 200 years of evolving energy use in the United States as an animated Sankey diagram. Line widths represent per capita energy flows each year from primary energy sources (left) to final uses (right). The project is an effort of the University of Chicago’s Center for Robust Decision-Making on Climate and Energy Policy (RDCEP), and its research is documented in Suits, Matteson, and Moyer (2020). a. What was the primary energy source used in the United States in 1800? What energy sector was the largest consumer of energy in 1800? Why was this the energy source of choice? Describe the energy content of the primary source as high, medium, or low.

Solution Biomass was the primary energy source until the 1880s. After the 1880s, coal and petroleum were introduced and used. Residential and commercial uses were the largest consumers. Trees had a medium energy content for home heating and were abundant as land was being cleared. b. What was the primary energy source used in the United States in 1900? What energy sectors expanded from 1800 to 1900? What changes in technology created a demand to change the source of energy? Why was this the energy source of choice?

Describe the energy content of the primary source as high, medium, or low. Describe how the change in overall energy use and sources may have impacted pollution (including greenhouse gases) compared to 1800.

Solution Coal was the primary source of power throughout the 1900s. Petroleum became a secondary power source. Coal was abundant and provided a relatively inexpensive source of power for steam engines, furnaces, and forges across the United States.

Coal has a high energy content. When coal is burned, it releases a number of airborne toxins and pollutants. They include mercury, lead, sulfur dioxide, nitrogen oxides, particulates, and various other heavy metals. c.

What was the primary energy source used in the United States in 2000? What energy sectors expanded from 1900 to 2000? What changes in technology created a demand to change the source of energy? Describe the energy content of the primary source as high, medium, or low. Describe how the change in overall energy use and sources may have impacted pollution (including greenhouse gases) compared to 1900.

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7-6

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

Solution Between 1900 and 2000, industrial and commercial sectors expanded, especially transportation and industry. Petroleum became abundant and had a high energy density per unit volume, making it the energy source of choice for the country’s growing transportation infrastructure. Natural gas and nuclear energy also increased later in the century. Coal and petroleum were the primary energy sources, followed by natural gas and nuclear power. The increase in petroleum and natural gas decreased overall acid gas pollution and mercury emissions from coal. d. What do you believe will be the primary energy source used in the United States in 2100? What changes in technology are most likely to result in changes to the source(s) of energy? Describe how the change in overall energy use and sources may impact pollution (including greenhouse gases) compared to the year 2000.

Solution Answers may vary.

Excellent

Good

Answers correctly describe energy sources and availability, energy switching to lower greenhouse gas emitting sources, estimate or provide refences for the amount of greenhouse gas reductions

Answers correctly describe energy sources and availability, energy switching to lower greenhouse gas emitting sources

Needs Improvement Answers mostly describe energy sources and availability, energy switching to lower greenhouse gas emitting sources

Poor

Unacceptable

Answers that describe energy sources and availability, energy switching to lower greenhouse gas emitting sources are only partially accurate

Answers misidentify energy sources and availability, energy switching to lower greenhouse gas emitting sources

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7-7

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

7.6. The U.S. EPA (2013) reported that, on average, an American home consumed the following energy resources. The U.S. EPA uses a simplified method of estimating an individual’s greenhouse gas emissions in their Household Carbon Footprint Calculator (https://www3.epa.gov/carbon-footprint-calculator). The carbon dioxide equivalent emission rates are estimated from the conversion factors in Table 7.3. What is the simplified carbon footprint for average home energy use in the United States? To answer this question, the individual GHG emissions for each category are calculated and then summed to estimate the total carbon footprint for an average U.S. household. a. Calculate CO2 emissions in metric tonnes per year for electricity from the home by multiplying the U.S. EPA carbon dioxide emission factor for household resource consumption by the amount of electricity consumed.

Solution Electricity usage: 11,319 kWh × 7.0555 x 10−4

tonnes CO2� = 7.99 metric tonnes CO2 kWh

b. Calculate CO2 emissions in metric tonnes per year for natural gas use from the home.

Solution Natural gas usage:

c.

66,000 ft 3 × 5.44 x 10−5

tonnes CO2� ft 3 = 3.59 metric tonnes CO2

Calculate CO2 emissions in metric tonnes per year for home gasoline use. There are 20 gallons of gasoline in a barrel.

Solution Home gasoline use: 464 gallons ×

barrel

42 gallons

× 0.2913

tonnes CO2� barrel = 2.42 metric tonnes CO2

d. Calculate CO2 emissions in metric tonnes per year for fuel oil use from the home.

There are 42 gallons of oil in a barrel.

Solution Home fuel oil use: 551 gallons ×

barrel

42 gallons

× 0.43

tonnes CO2� barrel = 5.64 metric tonnes CO2

e. Calculate CO2 emissions in metric tonnes per year for kerosene gas use in the home.

Solution Home kerosene use: 108 gallons ×

barrel

42 gallons

× 0.42631

tonnes CO2� barrel = 1.10 metric tonnes CO2

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7-8

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

f.

Calculate CO2 emissions in metric tonnes per year for transportation via automobile.

Solution Gasoline for automobile transportation: 2 cars ×

11,319 miles car

×

gallon

21.5 miles

×

barrel

42 gallons

× 0.2913

tonnes CO2� barrel = 5.58 metric tonnes CO2

g. Calculate the total CO2 emissions in metric tonnes per year for a typical home in the United States.

Solution The simplified carbon footprint for the average U.S. home is: (7.99 + 3.59 + 2.42 + 5.64 + 1.10 + 5.58) metric tonnes CO2 = 26.32 metric tonnes CO2 7.7. Create a scenario to demonstrate an energy development scenario using the En-ROADS simulator that limits global warming to less than 2°C (3.6°F) as agreed in the Paris Accord.

Note: There are many pathways to achieving the Paris goals to limit climate change, so you may focus on what you believe is most appropriate. Adjust the scenario and provide a brief explanation for each of the scenario variables below. a. How do you believe the population in the United States, the European Union, China, India, and developing countries will change across the planet by 2100? Population projections can be found from a variety of sources online. Be sure to document the source you use. Adjust the sliders on the simulator to account for the impact of population projections.

Solution Answers may vary. An example solution is shown below: Increasing investment in renewals and disincentivizing fossil fuel production are also great methods. We also believe investing in carbon capture technology and nuclear energy will help. b. How do you predict economic growth by gross domestic product per capita in the United States, the European Union, China, India, and developing countries will change by 2100?

Economic growth projections can be found from a variety of sources online. Be sure to document the source you use. Adjust the sliders on the simulator to account for the impact of population projections.

Solution Answers may vary. An example solution is shown below: Overall, the GDP per capita of every country seems to increase, according to the simulation.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

c.

How do you predict energy efficiency in buildings and industry will change by 2100? The U.S. EPA has a table available online that compares Green Building Standards that might be helpful (https://www.epa.gov/smartgrowth/comparison-green-buildingstandards). Adjust the sliders on the simulator to account for the impact of population projections.

Solution Answers may vary. An example solution is shown below: We believe that these countries should increase the overall electrical efficiency of electrical devices in the industrial sector as well as buildings. d. How do you predict energy efficiency in transportation will change by 2100? The U.S. Department of Transportation and other organizations may help you estimate reasonable improvements in transportation between 2020 and 2026. Adjust the sliders on the simulator to account for the impact of population projections.

Solution Answers may vary. An example solution is shown below: We believe that these countries will slightly increase the overall energy efficiency in the transportation sector. Overall, major differences will not be made. e. How do you predict the sources for energy supply will change by 2100? The U.S. Energy Information Agency’s Annual Energy Outlook (https://www.eia.gov/outlooks/aeo) provides a great deal of insight into how energy supplies may change between the present and 2050. Adjust the sliders on the simulator to account for the impact of population projections.

Solution Answers may vary. An example solution is shown below: The proportion of wind, solar, and nuclear will all increase. The usage of coal, petroleum, and other fossil fuels will decrease. f.

How do you predict the sources for land and industry emissions will change by 2100?

Adjust the sliders on the simulator to account for the impact of population projections.

Solution Answers may vary. An example solution is shown below: Land and industry emissions will go down as time goes on. g. How do you predict carbon removal will change by 2100? Adjust the sliders on the simulator to account for the impact of population projections. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

Solution Answers may vary. An example solution is shown below: Carbon removal should increase dramatically, be it from afforestation or carbon removal due to direct air capture.

7.8. Create a written or video report to demonstrate an energy development scenario using the En-ROADS simulator that limits global warming to less than 2°C (3.6°F) as agreed in the Paris Accord. Include each of the items below in your report: a. Describe how you predict changes in population in the United States, the European Union, China, India, and developing countries by 2100. Adjust the sliders on the simulator to account for all your scenario projections. Illustrate your projection impacts on population using the graphs to illustrate the population by region (on the left-hand graph) and the population exposed to sea-level rise (on the right-hand graph).

Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

As the world continues to grow, we can expect an increase in population for most of the countries involved. The EU is expected to see a decline by 2100. The U.S. is expected to remain close to the current population as we reach 2100. India expects to see a slight increase in population related to the age demographics, but return back to the current population number by 2100. China is looking at a slight increase in population currently, but it will be seeing a slightly steady decline. Other developed countries will remain the same © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

while other developing countries will experience a spike and steady increase in population as we approach 2100. This is all accurate if expectations remain at the status quo. This could change, however, as temperatures spike, water levels increase, and millions of people are at risk of flooding.

b. Describe how you predict changes in economic growth in the United States, the European Union, China, India, and developing countries by 2100. Adjust the sliders on the simulator to account for all your scenario projections. Illustrate your projection impacts on economic growth using the graphs to illustrate the gross domestic product per capita by region (on the left-hand graph) and the marginal cost of solar electricity history (on the right-hand graph). Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

We will see an increase in GDP per capita in each region. We expect China to have a greater GDP increase than the other companies in regard to how fast it increases. The United States

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7-12

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

and EU continue to have the largest GDP per capita. The other developing countries have only little change while India is only a slight increase compared to theory 2000 starting value. c.

Describe how you predict changes in building and industrial efficiency by 2100.

Illustrate your projection using the graphs to illustrate the electric share of total capital—buildings and industry and the marginal cost of solar greenhouse gas net emissions history. Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

We can see a small increase from 25% electric share of total capita in 2000 to around 35% electric share of total capita in 2020. We then see a spike from 2020 to 2100 which takes us to 100% electric share. This is just looking at the buildings and industry. Without seeing up to 2100 in solar greenhouse gas net, we can assume that it has remained steady or slightly decreasing since 2020 based on the graph below with the Marginal cost of solar from 1990 to 2100. Solar energy has become easier to use and cheaper overall. d. Describe how you predict changes in energy efficiency in transportation by 2100.

Illustrate your projection using the graphs to illustrate the electric share of total capital—transport and the air pollution from energy by source (area)—PM2.5. Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

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7-13

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

We can see through the graph that there is little to no increase in nuclear energy. After 2020, we see a drop in levels from bioenergy. There is a slight increase in levels of oil, gas, and coal up until 2022 when they significantly drop until they reach close to zero exajoules/year in 2100. We can also see that there is a significant difference between the baseline and current scenario of CO2 concentration. We are expected to have a decrease in levels after 2030 that will return back to measured levels of close to 390 ppm in 2000 by 2100. e. Describe how you predict changes in the sources for energy supply by 2100. Illustrate your projection using the graphs to illustrate the global sources of primary energy (area) and the CO2 concentration. Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

The current scenario is expected to decrease from the baseline at around 2020. We will see a drop in greenhouse gas net emissions where it will begin to level out at 10 gigatons of CO2 equivalent/year by 2060 until 2100. The increase of greenhouse gas concentration increases

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7-14

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

as the baseline predicted up until 2030 when it will remain steady around 500 ppm. This will continue until 2100. f.

Describe how you predict changes in the sources for land and industry emissions by 2100. Illustrate your projection using the graphs to illustrate the greenhouse gas net emissions (area) and the greenhouse gas concentration. Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

The current scenario is expected to decrease from the baseline at around 2020. We will see a drop in greenhouse gas net emissions where it will begin to level out at 10 gigatons of CO2 equivalent/year by 2060 until 2100. The increase of greenhouse gas concentration increases as the baseline predicted up until 2030 when it will remain steady around 500 ppm. This will continue until 2100. g. Describe how you predict changes in carbon removal by 2100. Illustrate your projection using the graphs to illustrate the CO2 emissions and removal and the temperature change. Take a screenshot of these graphs once all your scenario sliders have been finalized and include your visual and the interpretation of the graphs in your report.

Solution Answers may vary. An example solution is shown below:

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7-15

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

As we approach 2020, we see that CO2 emissions and CO2 removals are at their max where CO2 emissions are almost double what is being removed. Once we get to 2020, we see CO2 emissions decreasing until 2100. We see a cross between emissions and removal where in 2035 we have more removal than emissions. This contributes to its decrease. We can also see that the temperature has little to no change after reaching the 2030 mark and remains constant at 1.7 degrees Celsius up until 2100. The decrease in emissions is preventing the warming up baseline that was expected. h. What is the greatest financial challenge or uncertainty toward achieving your energy scenario? Illustrate your projection using the graphs to illustrate the financial challenge. Take a screenshot of the graph once all your scenario sliders have been finalized and include your visual and the interpretation of the graph in your report.

Solution Answers may vary. An example solution is shown below:

There is an increasing annual cost of energy until after 2020 when we see a spike up to 15 trillion dollars per year. This is then followed by a decrease in trillions until we reach 7 trillion dollars a year by 2100. This is significantly different from the baseline. We see a steady and slow decrease in final energy consumption until 2100 as well though, which could cause issues for businesses in the energy industry.

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7-16

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

i.

What is the greatest environmental challenge, uncertainty, or impact in your energy scenario? Illustrate your projection impacts using the simulation graphs to illustrate the biological or environmental challenges. Take a screenshot of the graph once all your scenario sliders have been finalized and include your visual and the interpretation of the graph in your report.

Solution Answers may vary. An example solution is shown below:

We would want to decrease deforestation and the release of emissions in the future, but of course it’s difficult to decrease emissions when it comes to industry. It will be difficult to significantly decrease the amount of deforestation as well due to the need for products made from wood. We see overall coal and oil contribute the most to the CO2 emissions. It’s going to be difficult substituting them due to the growing businesses involved with extraction. j.

What is the greatest challenge to human health and well-being in your energy scenario? Illustrate your projection impacts using the simulation graphs to illustrate the humanitarian challenges. Do you believe people living in high-income and lowincome countries will be equally affected by energy use scenarios in the future? Take a screenshot of the graph once all your scenario sliders have been finalized and include your visual and the interpretation of the graph in your report.

Solution Answers may vary. An example solution is shown below:

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

The greatest challenge is helping businesses understand that this is a necessity. We can also see deaths from the extreme heat. We believe that people in low-income countries will be more negatively affected by the energy-use scenarios due to their lack of resources that can be used for protection. They don't have the clean water, reinforced buildings, and heat protection that we do and will most likely experience more negative effects to their health. k.

What steps need to be taken (include science development, engineering, technology transfer, education, political actions, policy, and so on) over the span of the next five years to put your plan into action?

Solution Answers may vary. An example solution is shown below:

1. Conduct a baseline assessment: The first step in developing an energy efficiency plan is to

2.

3.

4.

conduct a comprehensive assessment of the current energy consumption patterns, energy sources, and energy efficiency measures in place. This will help identify the areas with the greatest potential for improvement and set realistic targets for energy savings.

Set goals and targets: Based on the baseline assessment, set clear and measurable goals and targets for energy efficiency improvements. These goals can include reduction targets for energy consumption, greenhouse gas emissions, and other relevant parameters. It's essential to involve stakeholders from academia, industry, government, and civil society in the goal-setting process to ensure broad support and commitment.

Develop an action plan: Create a detailed action plan outlining the specific measures and strategies to achieve the energy efficiency goals. This may include research and development of new technologies, engineering solutions for energy-efficient systems, technology transfer mechanisms to disseminate best practices, educational programs to raise awareness and capacity building, and policy and regulatory interventions to incentivize energy efficiency.

Invest in research and development: Science and technology development are crucial for advancing energy efficiency. Allocate resources for research and development (R&D) initiatives to develop innovative technologies, materials, and processes that can enhance energy efficiency across various sectors, such as buildings, transportation, industry, and agriculture.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 7: Designing for Energy Efficiency

5. Foster technology transfer and adoption: Once new technologies and best practices are

developed, focus on technology transfer mechanisms to disseminate them widely. This can include collaborations between academia, industry, and government to share knowledge and expertise, demonstration projects to showcase the benefits of energy-efficient technologies, and financial incentives to encourage the adoption of energy-efficient solutions by businesses and consumers.

6. Promote education and awareness: Education and awareness play a crucial role in driving behavioral change towards energy-efficient practices. Develop educational programs for different target groups, such as students, consumers, and industry professionals, to raise awareness about the benefits of energy efficiency, provide training on energy-efficient technologies and practices, and promote sustainable energy behaviors.

7. Engage in political actions and policy advocacy: Advocate for favorable policies and regulations that support energy efficiency. Engage with policymakers and relevant stakeholders to promote the adoption of energy-efficient standards, codes, and certifications. Lobby for financial incentives, tax credits, and other policy mechanisms that can drive investments in energy efficiency measures and technologies.

8. Monitor and evaluate progress: Regularly monitor and evaluate the progress of the energy efficiency plan against the set goals and targets. Use performance metrics and indicators to assess the effectiveness of implemented measures and identify areas that require further improvements. Adjust the action plan as needed to ensure continuous progress towards the energy efficiency goals.

9. Foster partnerships and collaborations: Energy efficiency is a complex issue that requires collaboration among various stakeholders. Foster partnerships and collaborations among academia, industry, government, civil society, and international organizations to pool resources, knowledge, and expertise, and work together towards achieving the energy efficiency goals.

10. Ensure long-term sustainability: Energy efficiency is a long-term endeavor that requires sustained efforts beyond the initial 5-year period. Develop strategies for long-term sustainability, including regular updates to policies and regulations, continuous R&D, capacity building, and awareness campaigns to embed energy efficiency as a culture and way of life.

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7-19

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

Solution and Answer Guide

Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

Chapter 8 Questions

8.1. Describe how the U.S. Bureau of Labor and Statistics defines an industrial engineer, the entry-level education required, and the median salary for industrial engineers by reviewing the Field of Degree highlights for students and job seekers in the Occupational Outlook Handbook.

Solution The Occupational Outlook Handbook defines what industrial engineers do as “devise efficient systems that integrate workers, machines, materials, information, and energy to make a product or provide a service.” The median pay for an industrial engineer is $95,300 per year or $45.82 per hour. Industrial engineers will need a bachelor’s degree at entry level.

8.2. Describe how the U.S. Bureau of Labor and Statistics defines a materials engineer, the entrylevel education required, and the median salary for materials engineer by reviewing the Field of Degree highlights for students and job seekers in the Occupational Outlook Handbook.

Solution The Occupational Outlook Handbook defines what materials engineers do as “develop, process, and test materials used to create a wide range of products.” The median salary for a materials engineer is $98,300 per year or $47.26 per hour. Materials will need a bachelor’s degree as entry level education.

8.3. Find job listings for an industrial engineering position and a materials engineering position.

Describe the similarities and difference between the education required, experience required, and salary range (if available) for the two different positions. What other educational degrees or requirements would be acceptable for the job listing you have found? You can find job listings through employment websites, USAJobs.gov, IISE.org, LinkedIn, and other professional networking websites.

Solution Answer may vary. A sample answer is provided below: Similarities include that both jobs require a degree in engineering, or experience in training, and/or technical experience with engineering. Differences include pay range; an industrial engineer makes generally $10,000 more than a materials engineer.

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8-1

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.4. Describe the weight of the rod.

Solution The “weight” of a fly-fishing rod is not a description of the mass of the rod. Instead, the “weight” of the fly rod is based upon the mass of the fly-fishing line it is designed to cast. A heavier “weight” rod will cast a fly line with a greater mass.

Useful resources: • •

HOW TO CHOOSE THE RIGHT FLY LINE WEIGHT Fly Rod Weight | Getting Started In Fly Fishing - Episode 2: https://youtu.be/Cj9mTtXFm5U

8.5. Describe the length of the rod.

Solution The length of the rod is often chosen due to the type of water and the characteristics of the material of the rod blank. Anglers fishing in small streams that are covered by small trees and brush may prefer rods from 1.8 to 2.5 meters. Anglers fishing along an ocean beach or large river might prefer a rod that is up to 3.6 meters long. The most common rod blank length is 2.75 meters, a very good compromise between the shorter and longer lengths.

8.6. Create a list of materials you think you may need to make the rod.

Solution a. Rod Blank - The rod blank is the long flexible pole component of the rod. The types of materials that can be used for the blank are bamboo, fiberglass, and graphite (carbon composite). Bamboo is not that popular and has super slow action.

Fiberglass used to be super popular and is making a comeback. These blanks also have super slow action. The best and most common type of blank is graphite. There are multiple action types with graphite, and these have the best performance out of all the rods. b. Grip/Handle - The grip is the aspect of the handle assembly that the angler holds on to. The grip can come in various materials like cork, EVA, Hypalon, cork tape, cord, wood, and shrink tube. Cork rings give the rod a classic and stylish look. They also add weight to the rod and are easy to work with. Cork tape is inexpensive, easy to apply, and popular with surf rods. It has a soft feel but needs to be replaced over time. Shrink wrap is installed over another grip and is very durable and aesthetically pleasing. EVA Foam is dense, lightweight, and comfortable. These grips are good for anglers that plan on doing freshwater and light saltwater fishing. The EVA has little stretch and must be carefully considered before installation. Hypalon is extremely durable due to its ability to stretch. This is a good grip for a rod that will be placed in a rod holder. Cord grips are the best for messy and dirty hands. These are extremely durable but are heavy and difficult to create. These grips are best used for boat anglers.

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8-2

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

c.

Reel Seat Insert/Hardware - Reel seats are the aspect of the rod that hold the reel into place. They secure the reel to the rod and are a part of the handle assembly.

Reel seats can be made from metal, graphite, or electrical tape. If a more secure connection is desired, a metal or graphite reel seat would be desired. For heavy offshore rods, metal seat is preferred, while lighter saltwater and freshwater rods typically use graphite. If you are going to use the rod in cold weather, a graphite seat is desired, as it is not as cold to the touch. Electrical tape can be used if the aesthetics of the rod do not matter, and a secure connection is the only aspect desired. d. Guides - Guides are the aspect of the rod that keep the fishing line in place and connected to the rod. There are three types of guides: stripping guides, running guides, and tip tops. Almost all guides are made from a corrosion resistant stainless steel, and most are plated. There are chrome, titanium, and titanium/nickel alloy types of plating. The guide inserts are typically made from silicon carbide, zirconium, or aluminum oxide. e. Wrapping Thread - The wrapping thread is the aspect of the rod that covers the inserts of the guide. The thread helps to hold the guide in place and prevent any movement from occurring. Wrapping thread can come in regular nylon, metallic, polyester, and color treated thread. Metallic thread is not that strong, and it is used for decorative aspects more often. Nylon thread allows for the best performance. f. Finish - The finish on a rod is the cover coat that makes the rod look complete. The finish on a rod can range from a rod varnish or epoxy/glue finish. A rod varnish is meant to coat the rod blank and is more like a stain. Rod varnish can range from polyurethane or thinners while epoxy is simply epoxy resin glue.

Useful Resources: • Bamboo Rod making for Beginners. https://peakbamboo.com/bamboorodmaking-for-beginners/ • About Cork. https://pacecork.com/about-cork/ • New Fiberglass Rods Revolution: https://www.flyfisherman.com/editorial/newfiberglass-rods-revolution/151902 • Fiberglass and Composite Material Design Guide 8.7. Describe how you will judge if your rod is more sustainable (greener, more environmentally friendly) than other teams. Create a table that shows the following: a. Five or more things you might measure to describe how your design is more or less sustainable than other designs. b. List the unit of measure for each of the metrics you list in part a.

Solution Solutions may vary Excellent

Good

Answers correctly

Answers correctly

Needs Improvement Answers describe factors

Poor

Unacceptable

Answers partially

Answers misidentify factors

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8-3

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

describe factors affecting material choice for each category in performance, environmental impacts, costs (economic impact), and use (social impacts)

describe factors affecting material choice for two categories in performance, environmental impacts, costs (economic impact), and use (social impacts)

affecting material choice for some categories in performance, environmental impacts, costs (economic impact), and use (social impacts)

describe factors affecting material choice for only one in performance, environmental impacts, costs (economic impact), and use (social impacts)

affecting material choice and do not address most categories of performance, environmental impacts, costs (economic impact), and use (social impacts)

Useful resources: • • •

•

•

•

•

•

•

•

How to select a fly rod: https://www.bigskyfishing.com/fly-fishing-articles/howselect-fly-rod.php Bamboo LCA (Life Cycle Assessment) and EPD (Environmental Product Declaration) https://www.moso-bamboo.com/us/lca/?lang_selected=true The Environmental Impact of Industrial Bamboo Products: Life-cycle Assessment and Carbon Sequestration https://repository.tudelft.nl/islandora/object/uuid%3A2b1f58e2-2a72-4247bf57-49eb7d5646a1 Agyekum, E.O., Fortuin, K.P.J. and van der Harst, E. (2017) Environmental and social life cycle assessment of bamboo bicycle frames made in Ghana, Journal of Cleaner Production, Volume 143:1069-1080, https://doi.org/10.1016/j.jclepro.2016.12.012.

Demertzi, M., Silva, R.P., Neto, B., Dias, A.C., and Arroja, L. 2015. Cork stoppers supply chain: potential scenarios for environmental impact reduction. Journal of Cleaner Production, http://dx.doi.org/10.1016/j.jclepro.2015.02.072.

Dias, A.C., Boschmonart-Rives, J., González-García, S. et al. Analysis of raw cork production in Portugal and Catalonia using life cycle assessment. Int J Life Cycle Assess 19, 1985–2000 (2014). https://doi.org/10.1007/s11367-014-0801-7 Life Cycle Assessment: Are composites "green"?: https://www.compositesworld.com/articles/life-cycle-assessment-arecomposites-green Life Cycle Analysis – Environmental Effects of carbon Composite Materials: https://specomposites.wordpress.com/2013/06/25/life-cycle-analysisenvironmental-effects/ Whitaker, A.F., Finckenor, M.M., Dursch, H.W., Tennyson, R.C., Young, P.R. (1998).

Environmental Effects on Composites. In: Peters, S.T. (eds) Handbook of Composites.

Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-6389-1_37 La Rosa, Angela & Banatao, D.R. & Pastine, S.J. & Latteri, Alberta & Cicala, Gianluca.

(2016). Recycling treatment of carbon fibre/epoxy composites: Materials recovery and characterization and environmental impacts through life cycle assessment.

Composites Part B: Engineering. 104. 10.1016/j.compositesb.2016.08.015.

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8-4

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.8. Briefly describe the mechanics of the forces that act on the fly rod. You may also use resources (there are many) that describe the physics of fly casting. Use a sketch to show the forces acting on the rod during the following: a. The back cast b. The pause between the back cast and the forward cast c. The forward cast Solution a. During the casting process there are various stages. After laying out the line to start, a back cast is made to extend the line fully behind the fly-caster in an overhead cast.

While in motion during an overhead cast, the line should make a “U” shaped loop. A perfect loop is generally tight (with both halves of the loop close to one another), has parallel legs, a wedge or arrow-shaped nose to it, and unrolls with the right amount of power. It is in the back cast where the rod starts to flex backwards. While still in control of the rod, the back cast allows the rod and line to have maximum potential energy at the point directly before the force and torque is applied. b. A pause occurs as the rod changes from a spring-loaded backwards angle and reverses direction. Near the pause, the fly line is straightened behind the fly-caster, the user applies force and torque to the base of the rod to cause the rod tip and the fly line to flex and accelerate. c. The forward cast begins and is aided by the force that loads the “spring-action” of a flexed fly rod during the pause. As the rod straightens and begins to flex forward, the rod tip velocity decreases and the fly line travels free of the rod motion. Once the flycaster applies the force, the rod releases stored potential energy and converts it to the kinetic energy which is transferred to the fly line. This relationship of energy being transferred between the rod moving in the back and front cast is known as the conservation of kinetic energy principle.

Useful Resources: •

Spolek, Graig A.,(1986). The Mechanics of Flycasting: The Flyline. American Journal of Physics, 54, 832-836.

8.9. Briefly describe the casting process and the role of the fly-fishing rod in that process. The Fly Rod Selector may help you get a sense of important questions to ask when designing your rod (https://www.orvis.com/fly-rod-selector.html). You may also find information from a local fly-fishing shop if there is one located nearby.

Solution All of the materials in the fly rod impact the properties in regard to the casting process. The fly rod has three main purposes. These purposes are casting, line control, and striking & landing the fish. The action of a fly rod refers to how flexible the rod is. There are three main types of rod action, and they are differentiated by how flexible the rod is. The fast action (tipflex) rod refers to just the tip of the rod slightly bending with the rest of the rod virtually straight. The medium action (mid-flex) rods are the most versatile and they bend from the tip to about the halfway point on the fishing rod. The slow action (full flex) rods are

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8-5

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

extremely flexible and encompass the whole rod bending on the back cast. The length of the rod also plays a role when selecting materials. A longer rod is used for longer casts and heavier fishing line while a shorter rod is used for short casts and lighter fishing line.

Useful Resources: • • •

Wanga, G. and Wereleyb, N. (2011) Analysis of fly fishing rod casting dynamics. Shock and Vibration. 18 (2011) 839–855 839. DOI 10.3233/SAV-2010-0605 ORVIS – Fly Casting Lessons – The Basic Fly Cast. https://youtu.be/oDJJ6W23gHw ORVIS – Fly Casting Lessons – There’s No Right Style of Casting. https://youtu.be/odp3-zMj9Dw

8.10 Briefly describe the role of the fly-fishing line in the casting process, including a description of what type of line might be most appropriate for your intended use.

Solution Everything in the fly rod’s combination lever and spring system is dependent upon the fly line. Fly line is weighed in grains. These grains were given a numbering system that allows anglers to easily determine what weight fly line they may need. The weighting system goes from a 1 weight to a 16 weight, with 1 being the lightest and most delicate line and 16 being the heaviest and most durable. The weight of the line is what casts the fly.

Different fly line weights are used for different purposes. A1, 2, & 3 weight fly line is ultralight and used for trout, dry flies, and panfish scenarios. A4, 5, & 6 weight fly line is all around fly line and is used for trout, smallmouth, & bass scenarios. A7, 8, & 9 weight fly line is heavy duty and used for largemouth bass, salmon, steelhead, pike, and saltwater scenarios. A10, 11, & 12 weight fly line is used for musky and saltwater fishing. Lastly, A13, 14, 15, & 16 weight fly line is used for blue water, sail fish, marlin, and tuna. Thus, the weight of the line heavily influences the rest of the fly rod system. The materials in the fly rod and line system work in unison to allow an angler to perfectly drop a fly on the water to mimic nature in the best possible way.

Useful Resources: • Fly Lines Explained: https://www.flyshop.co.nz/fly_lines.html 8.11 Understanding the material choices is critical in design and manufacturing. Often, there may be many alternative materials that function appropriately for the design problem.

There will be trade-offs in terms of cost, function, and environmental impacts. Briefly describe the materials you choose for each of the components listed. a. Rod blank b. Handle c. Reel seat insert and hardware d. Fly line guides e. Guide wrapping thread f. Protective coating to cover the guide wraps

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8-6

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

Solution a. Rod Blank - The rod blank is the long flexible pole component of the rod. The types of materials that can be used for the blank are bamboo, fiberglass, and graphite (carbon composite). Bamboo is the original material and has super slow action but is a much heavier material than modern composite materials. Bamboo is a natural, renewable material and it may decompose at the end-of-life. Fiberglass became popular and is still used in slow-to medium action rod blanks. Fiberglass is a composite material made from glass fibers and petroleum-based resin material and it does not decompose at the end-of-life. Fiberglass has a higher strength to weight ratio than bamboo and is less rigid than carbon composite materials. Graphite or carbon composite rods are made predominantly from carbon fiber tubes, and they use a petroleum-based resin material like fiberglass resins to provide shape and form. Most fly rods produced today, especially by larger manufacturing companies, use carbon composite materials due to their high strength and low weight. b. Grip/Handle - The grip is the aspect of the handle assembly that the angler holds on to. The grip can come in various materials like cork, EVA, Hypalon, cork tape, wood, and numerous other material possibilities. Cork rings are a natural biodegradable material and the traditional grip used on most fly rods. However, cork trees can be over harvested, so while a renewable resource, it is not an infinite resource. Cork tape is inexpensive, easy to apply, and popular with surf rods. It has a soft feel but needs to be replaced over time. EVA Foam is polymer-based material that is dense, lightweight, and comfortable. These grips are good for anglers that plan on doing freshwater and light saltwater fishing. The EVA has little stretch and must be carefully considered before installation. Hypalon is extremely durable due to its ability to stretch. This is a good grip for a rod that will be placed in a rod holder. Cord grips are the best for messy and dirty hands. These are extremely durable but are heavy and difficult to create. c. Reel Seat Insert/Hardware - Reel seats and associated hardware secure the reel to the rod and are a part of the handle. Reel seats may be made from any material that does not retain water. Common insert materials on which the reel sits include wood, acrylic, metal, and composite materials. The hardwater clap the reel to the insert and are almost exclusively made from aluminum, steel, or other metal alloys. d. Guides - Guides keep the fly line in place along the length of the rod. There are three types of guides: stripping guides, running guides, and tip tops. The two most common shapes used on flu rods are S-shaped or circular with a “foot” that is attached to the rod blank with the wrapping thread: the aspect of the rod that keep the fishing line in place and connected to the rod. Almost all guides are made from a corrosion resistant stainless steel, and most are plated. The guide closest to the reel is called the stripping guide and this guide often has a material insert lining the inside of the circular guide. The insert material is typically made from silicon carbide, zirconium, aluminum oxide, or natural stone materials like agate. e. Wrapping Thread - The wrapping thread covers the “feet” of each guide and holds the guide to the rod blank. The thread holds the guide in place and prevents movement. Wrapping thread can come in silk, nylon, metallic-coated nylon, polyester, and other color treated thread.

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8-7

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

f.

Finish - The finish on a rod is a chemical coating that protects the rod from weathering. The guides are most often covered with a two-part chemical epoxy to protect the wrapping threads. The finish on a rod can range from a rod varnish or epoxy/glue finish. A rod varnish is meant to coat the rod blank and may be made from natural varnish materials or naturally occurring oils like tung oil. Rod finishes may be polyurethanes or thin epoxy coatings.

Useful resources: • Fly Rod Building 101: https://www.flyrodcrafters.com/rod-building-101/ • Designing your custom fly rod: http://flyrods.weebly.com/designing-your-customfly-rod.html 8.12 Cite one or more sources (website, catalog, store, and so on) for the materials chosen.

Note: The sources may be updated or changed later in the project.

Solution Answers may vary. An example solution is shown in the following Table: Table 1: Chosen Fly Rod Part Material and Place to Buy Fly Rod Part Chosen Part Location to Material Purchase Part Rod Blank Graphite Custom Fly Rod Crafters Grip Handle

Cork

Custom Fly Rod Crafters

Reel Seat Insert/Hardware Guides

Metal

Wrapping Thread

Nylon

Custom Fly Rod Crafters Custom Fly Rod Crafters Custom Fly Rod Crafters

Finish

Epoxy

Chrome

Custom Fly Rod Crafters

Hyperlink and Full Product Name Fly Rod Crafters XI Graphite 4PC Fly Rod Blank Western Cork Grip – Super ‘Flor Plus’ Grade Y-Style All Metal Fly Reel Seat Chrome Snake Guide Set with Tip Top Set Forest Hitena Nylon Rod Wrapping Thread Flex Coat Rod Finish – High Build Super Kit

8.13 What is the cost of each component used in the design of the fly rod?

Solution Answers may vary. An example solution is shown in the following Table: Table 2: Chosen Fly Rod Part Material and Price

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8-8

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

Fly Rod Part Rod Blank

Chosen Part Material Graphite

Grip Handle

Cork

Reel Seat Insert/Hardware Guides

Metal (Aluminum) Chrome

Wrapping Thread

Nylon

Finish

Epoxy

Hyperlink and Full Product Name Fly Rod Crafters XI Graphite 4PC Fly Rod Blank Western Cork Grip – Super ‘Flor Plus’ Grade Y-Style All Metal Fly Reel Seat Chrome Snake Guide Set with Tip Top Set Forest Hitena Nylon Rod Wrapping Thread Flex Coat Rod Finish – High Build Super Kit

Price $59.95

$23.95 $22.95 $15.68 $3.99 $17.99

8.14 Describe the raw materials associated with each component. Find a possible geographic location and repository for the raw materials of each component (i.e., where in the world are the materials found, mined, or grown).

Solution Answers may vary. Example solutions may include the following: a. Rod Blank: i. Bamboo is a renewable resource. Bamboo used in modern bamboo rods comes exclusively from the Tonkin region of China. In this process, the bamboo is grown, harvested, dried, split and formed into laminated strips used to produce the fly rod. ii. Fiberglass (or fiberglass reinforced plastic, FRP) is made from glass fibers and thermoset plastic epoxy resin. The fibers’ primary material is silica, a type of silicon oxide polymer that does not have a melting point and has long been used for its hardness properties. Silica is commonly found in sand or quartz and is used to create many types of glass, including window glass, drinking glasses, and optical fibers. There are various types of fiberglass, distinguished by their chemical makeup. The United States is the leading producer of fiberglass materials and components. iii. Graphite is most often found as flakes or crystalline layers in metamorphic rocks. Graphite is exported by a variety of countries, but China, Mozambique, Brazil, and Madagascar were the lead mine producers in 2020.

2) Grip Handle (Cork): Cork comes from the Cork Oak Tree that is mainly found in the Mediterranean nations, especially Portugal and Spain. Laws in those nations require that the tree must grow for 25-34 years before cork can be harvested.

3) Reel Seat Insert/Hardware (Metal - Aluminum): Aluminum compounds can be found in all types of clay, but the ore most useful for producing pure aluminum is bauxite. This ore consists of 40-60% of aluminum oxide. Some bauxite deposits are hard rock, but

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8-9

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

most consist of soft dirt that is dug from open-pit mines. Australia produces more than one-third of the world’s supply of bauxite.

4) Guides (Chrome): Chrome is a steely-gray, hard metal that takes a high polish and has a high melting point. Chromite is the only ore of chromium, and it comes in two deposit forms that are layered or pod shaped. Both are associated with the igneous rock formations. The world’s largest chromite deposits are found in South Africa.

5) Wrapping Thread (Nylon): Nylon is a type of synthetic polymer that is commonly used to make a variety of apparel and consumer goods. Nylon is made from the extraction of diamine acid, which is extracted from crude oil. The largest producer of crude oil is the United States. The largest producers of nylon are the U.S., Brazil, Pakistan, India, and China.

6) Finish (Epoxy): Epoxy resins are produced from raw materials that are mainly derived from petroleum. An epoxy resin is a polyoxide comprised of reactive prepolymers and polymers that contain epoxide groups. Larger petroleum producing regions and nations include the United States, Middle Eastern countries, Russia, and Venezuela.

8.15 Create a draft sketch of the material flow process for making a fly rod. Start with the raw material required (cradle). Include the intermediate steps required to process the raw materials and create engineered materials used to make each of the components of the fly rod. Don’t forget the transportation steps that are required to move the material from one step to the next in your sketch. Finally, consider the processes required to get the fly rod to the customer. Note: This will be a draft and will be updated as we move forward with the project and design.

Solution Answers may vary. Example solutions may include the following:

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8-10

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.16 For the components chosen below, create a graphic to visualize the flow of materials and energy throughout the design life of a fishing rod. Each member of your team may choose a different component. The schematic should include manufacturing steps in acquiring the raw material (cradle), processing the raw material, product manufacturing, product sales, product use, and product disposal (grave) as well as the transportation steps and types of fuel consumed in each. This is a qualitative visual tool; it does not need to be quantitative. a. Rod blank b. Handle c. Reel seat insert and hardware d. Fly line guides e. Guide wrapping thread f. Protective coating to cover the guide wraps Solution Answers may vary. Example solutions may include the following:

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8-11

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.17 For the components chosen, add elements that include the flow of energy throughout the cradle-to-grave life cycle of a fishing rod. Each member of your team may choose a different component. Embodied energy is fundamentally a value that assumes that the production processes for any given material are identical. Is this a valid assumption? Why or why not?

Solution Answers may vary. Example solutions may include the following: a. Fly Rod Blank

b. Fly Grip/Handle

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8-12

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

c. Reel Seat/Insert

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8-13

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

d. Guides and Wrapping Thread

e. Finish and Coating

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8-14

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.18 Identify on the diagrams from Problems 8.16 and 8.17 the sources of waste energy or materials. For example, this could be wasted heat in electricity production or wasted cork powder created when manufacturing the handle.

Solution Answers may vary. Example solutions may include the following: a. Fly Rod Blank - For the rod blank, the waste energy comes from fossil fuel emissions and heat loss. The material wastes are the different forms of bamboo throughout the manufacturing stages.

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8-15

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

b. Fly Grip/Handle - For the grip handle, the waste energy comes from fossil fuel emissions, heat loss, and solar energy. The material wastes are the different forms of cork throughout the various manufacturing stages.

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8-16

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

c.

Reel Seat/Insert - For the reel seat insert/hardware, the waste energy comes from the fossil fuel emissions and heat loss. The material wastes are soil and mineral loss, aluminum oxide material loss, and aluminum scraps lost.

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8-17

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

d. Guides and Wrapping Thread - For the guides, the waste energy comes from fossil fuel emissions, heat loss, and carbon dioxide loss. The material wastes are excess rock and excess stainless steel during manufacturing. For the wrapping thread, the waste energy comes from the fossil fuel emissions and heat loss. The material wastes are nylon waste during manufacturing

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8-18

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

e. Finish and Coating - For the guide and wrap finish coating, the waste energy comes from the fossil fuel emissions and heat loss. The material wastes are excess tung tree seed shells and tung tree oil.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

8-19

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.19 Tables for embodied energy for various materials are provided in Table 8.1 for embodied energy. Using these tables or other referenced sources, determine the embodied energy for your individual component (a–f). Note that this will include determining the mass associated with the various components. The component weights may be determined through vendor supplied information.

Solution Answers may vary. Example solutions may include the following:

Material Rod Blank (Composite Carbon Fiber - Graphite) Grip/Handle (Cork) Reel Seat Insert/Hardware (Aluminum Metal) Guides (Steel – stainless) Wrapping Thread (Nylon) Guide & Wrap Finish (Epoxy Resin)

Weight (grams) 50.3

Embodied Energy (MJ/kg) 315

Embodied Energy (kJ) 15,844.5

16.1 24

4 155

64.4 3720

2.5

56.7

141.75

0.4

137

54.8

0.2835

130

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36.9

8-20

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

Useful Resources: Materials required for building a fly rod – Part 1 the rod blank: https://youtu.be/T3hK8Xod1kg Materials for building a fly rod – Part 2 grips and guides: https://youtu.be/YqEy178XdTU

8.20 Calculate a sustainability indicator based on embodied energy for your design. Using the embodied energy data from the group, calculate the total embodied energy for your team’s fishing rod design. Hint: If this is done in a spreadsheet, it could be easily updated in case your design changes in the future.

Solution Answers may vary. Example solutions may include the following: 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 = 15,844.5 + 64.4 + 3,720 + 141.75 + 36.9 + 54.8 = 19,862.3 𝐾𝐾𝐾𝐾 8.21 Determine if there are any existing synergies in the production process that could utilize the waste from one process as a resource in another process and show these on your diagram.

Solution Answers may vary. Example solutions may include the following: •

•

All the energy flow diagrams show a form of heat energy loss. Heat could be recovered and used during manufacturing a bamboo rod blank diagram, as heat is needed during the bamboo hot press manufacturing process and during the treatment process. Heat recovery may also be possible in the reel seat insert/hardware since heat is needed for the smelting process and for the treatment process. With the guides process, heat is needed for the smelting process, for the hot rolling process, for the shaping process, and for the heat treatment process. For the wrapping thread diagram, heat is needed for the polymer creation process and for the polymer molten creation process. Within the guide and wrap finishing energy process diagram, heat is needed for heating the oil.

Rock, soil, and minerals are lost during the crushing manufacturing production process. Mineral could be considered for multiple materials needed in creating aluminum and stainless-steel, including aluminum, iron, chromium, silicon, etc.

Waste soil, minerals, and rock may also be treated and utilized for mine recovery efforts.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.22 Brainstorm, identify, and list one or more industries that could use waste from a fly rod manufacturing process as a raw material or resource in producing a different process.

Solution Answers may vary. Example solutions may include the table below that identifies and documents one industry that can use waste from the fly rod manufacturing process materials to produce something else.

Fly Rod Part

Waste Material

New Industry

Rod Blank

Excess Bamboo Chips

Grip/Handle Reel Seat Insert/Hardware Guides

Excess Cork Strips Excess Aluminum from Casting Excess Stainless Steel from Guide Formation Excess Recycled Nylon Excess Tung Tree Oil

Bamboo Pulp & Paper Industry Wine Industry Soda & Water Cans

New Possible Product Bamboo Printer Paper Wine Corks Aluminum Cans

Home Appliances

Refrigerator

Clothing Industry

Recycled Patagonia Jackets Water-Resistant Finish on Boats

Wrapping Thread Finish

Boat Industry

8.23 There are many options and many marketable designs for a fly rod—thus the reason there are so many different manufacturing companies and rod types within a company’s line of fly rods. This is your time to ask questions and push boundaries. It is okay to realize you made a mistake later after the analysis. Can you innovate and conceptualize a design no one else has considered? Think of an alternative material for the components in your fly rod design that may be “greener.” It may be bio-based, locally sourced, and so on. Find one such alternative for each of the following component options: a. Rod blank b. Handle c. Reel seat insert and hardware d. Fly line guides e. Guide wrapping thread f. Protective coating to cover the guide wraps Solution Answers may vary. Example solutions may include the table below that identifies alternative materials to produce the functions of the fly rod components.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

Fly Rod Component

Original Material

Rod Blank

Graphite

Grip Handle

Cork

Reel Seat Insert/Hardware

Insert: Acrylic, Wood Hardware: Metal (Aluminum)

Guides

Steel

Wrapping Thread Finish

Nylon Epoxy

Alternate Material Options Bamboo, bio-based composites Recycled Cork, recycled plastic, reused wood Insert: Corn cob, bamboo, reused wood, recycled cork (nearly anything can be used as a reel seat) Hardware: Recycled Aluminum, Recycled Steel Stainless Steel – Chrome Finish Silk Tung Oil, water-based finish, bio-based epoxy

8.24 Update your previous design with any design changes you may have made in your response to Problem 8.20. a. Briefly describe the materials (a)–(f) for each of the components listed above. b. Cite a possible source for the new materials chosen. c. Describe the cost per rod for each choice of materials (a)–(f). d. Update the sketch of the material flow process from cradle to grave (or cradle to cradle) for each material choice.

Solution Answers may vary. Example solutions may include the following: a. Rod Blank: Bamboo is a more natural fly rod blank material as it is more decomposable when compared to the typical fiberglass and graphite fly rod blanks.

Most the bamboo for these rod blanks is sourced from China where a lot of bamboo is grown. Usually, these rods are made from a single culm of bamboo. Bamboo has a much lower embodied energy value when compared to the fiberglass and graphite rod blanks as well.

More information: Angler’s Bamboo Company: https://www.anglersbambooco.com/ International Bamboo and Rattan Organization: https://www.inbar.int/bambooculms-low-cost-practical-construction-materials/

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

b. Grip Handle: Recycled cork has the potential to reduce cork bottle stopper waste and reduce the embodied energy compared to virgin cork.

More information: Cork Forest Conservation Alliance: https://corkforest.org/cork-reharvest/ c.

Reel Seat Insert/Hardware: Nearly any waste product could be used for the insert, as long as it is hydrophobic, such as stabilized corncob. Recycled aluminum or stainless steel are two of the most sustainable metals due to their ability to be recycled.

More information: Stabilized corncob: https://www.woodturningz.com/Stabilized_Corn_Cob

d. Guides: As previously mentioned, high recycled content stainless steel, is a good choice. e. Wrapping Thread: Silk thread is a biologically produced biodegradable alternative to nylon thread that has been used traditionally in fly rod building. Bio Nylon is a possible environmentally friendly replacement that is compostable. To make this nylon, a special formula was created that allows the nylon to break down once disposed of.

More information: Fishhawk Rod Winding Thread: https://fishhawkthreads.com/thread_silk.html f.

Finish: Tung oil is a natural finish extracted from the seed of the tung tree which is native to China and other Asian countries. It is stated to be 100% pure and extremely ecofriendly. It is a good finish to use on woody materials to give a water resistant, protective, and glossy finish.

Bio-based epoxy is another alternative. There are several supplies of bio-epoxy resins on the market. The USDA BioPreferred certification program provides standards for source ingredients certified under the USDA Certified Biobased Product label program.

More information: This Old House, How to Pick Tung Oil Finishes: https://www.thisoldhouse.com/woodworking/21015659/how-to-pick-tung-oilfinishes Entropy Resins: https://entropyresins.com/sustainability/life-cycle-assessment/

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.25 The global fishing rod market was valued at $1.03 billion 2021! It’s estimated that about 500,000 fly-fishing rods are built each year. You will create a company to produce environmentally friendly fly rods. You will base your marketing materials on an assessment that includes embodied energy analysis and an analysis of greenhouse gas emissions. Write a short paragraph describing the goal and scope of an LCA to estimate greenhouse gases associated with your manufacturing process. This assessment will be useful to venture capitalists to determine if they should invest in your company.

Solution Answers may vary. Example solutions may include the following: Fly Rod Part Greener Material Source of Material Cost Option Material Rod Blank Bamboo Proof Fly Fishing $475.00 Grip Handle Portuguese Cork Epic Fly Rods $50.00 Reel Seat Aluminum Get Bent Fly Shop $16.95 Insert/Hardware Guides Stainless Steel – Snake Guides $2.19 Chrome Finish Wrapping Biodegradable Nylon Paradise Fibers $3.50 Thread Fiber Finish Tung Oil The Real Milk $13.99 Paint CO.

8.26 Create an inventory analysis of the materials required for one full year of operation for your company. a. Estimate how many rods your team will produce in a year and offer for sale as part of a proposal for a business plan (this may range from tens of rods to thousands of rods, depending on your customers). b. Determine and report the total mass of raw materials needed for each component used to build your rod. (Don’t forget to include estimated waste produced in each step.) c. Find a source for the materials used in your rod. (This may be the raw material extracted or where a finished component is produced before it would go to your assembly plant.) Look online for a source material or supplier for each component. d. Determine the distance from the source of each material through your process from raw materials to manufacturing and then on to a supplier near you. Make any appropriate assumptions that are necessary.

Solution Answers may vary. Example solutions may include the following: a. For a one-person business, it may be possible to build on average 10 rods per week or about 500 rods per year. For simplicity purposes, we will assume 1,000 rods per year for the following solutions. (Which is about the number © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

many small fly-rod building companies produce). The customer base would be for high-end, custom fly rods that are climate friendly to protect coldwater trout fisheries. The selling price per rod would be between $1,200 and $1,500. b. The mass of materials for building 1,000 complete fly fishing rods composed of a 9 foot 5 weight bamboo rod blank, cork handle, reel set, insert, guides, wrapping thread, and estimated finish are presented in the following table.

Fly Rod Part

Material Option

Rod Blank Grip Handle Reel Seat Insert/Hardware Guides

Bamboo Portuguese Cork Aluminum

Wrapping Thread Finish

Stainless Steel – Chrome Finish Biodegradable Nylon Fiber Tung Oil

Source of Material Proof Fly Fishing Epic Fly Rods Get Bent Fly Shop Snake Guides Paradise Fibers The Real Milk Paint CO.

Mass (kg) 61.0 16.1 25.5 2.5 0.3 0.4

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 𝑜𝑜𝑜𝑜 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓ℎ𝑒𝑒𝑒𝑒 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 (𝑘𝑘𝑘𝑘) = 61.0 + 16.1 + 25.5 + 2.5 + 0.3 + 0.4 = 105.8 kg.

Assuming approximately 30% material waste, then the total mass would be: Total mass of all materials = 105.8 * 0.30 + 105.8 = 151.0 kg c.

The following assumptions were made in the example solution: The bamboo source for the raw material is Fujian, China, the raw material is manufactured within the province, shipped to Chicago, Illinois, then to central Virginia. The source for the cork grip is south-central Portugal near the city of Coruche, manufacturing is done in Mozelos, Portugal. The working cork material is shipped to Wanaka, New Zealand, where it is formed into a handle, then shipped to central Virginia. The aluminum source for the raw ore is in China near the Henan Province. The ore is shipped to a smelting factory in Hong Kong, China. The aluminum is shipped to St. Louis, MO, to manufacture the reel seat, which is then shipped to central, VA. The iron ore for stainless steel components originates in the Hamersley Province of Australia. The ore is shipped to a steel plant in Carroll County, Kentucky. The stainless steel is shipped to the component manufacturer in Battle Ground, WA, and the finished guides are shipped to central Virginia. Biodegradable nylon fiber is sourced from recycling plants in Premnitz, Germany, and it is shipped to a manufacturer in Berlin. From there, the nylon fiber is shipped to a distributor in Spokane, WA, and then onto central Virginia. The source of the tung tree

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

oil seed is the Sichuan province in Southern China. The seeds are then transported to the oil producing factories located in the Chinese Province, Hubei. The oil is shipped to a distributor in Hohenwald, Tennessee, and then onto central Virginia. d. Distance for shipping components to central Virginia or other destinations can be determined using Google maps or other mapping software.

Fly Rod Part

Rod Blank Grip Handle Reel Seat Insert/Hardware Guides Wrapping Thread Finish

Raw Material to Manufacture (km) 48 270 1,385

Manufacturer to Distributor (km) 11,817 19,558 12,775

Distributor to central Virginia (km) 1,148 14,477 1,198

1,141

12,349

980

17,976 89

3,801 7,941

4,500 4,020

Useful resources: The Hook & Hackle Company, "Building Your Own Custom Rod," The Hook & Hackle Company, 2022. [Online]. Available: https://www.hookhack.com/html/rodbuildinginstructions.html#:~:text=Our%20thoug ht%20is%20this%3A%20If,have%20a%20little%20patience%20too!. [Accessed 26 March 2022].

8.27 Show the boundaries of your material and energy flow analysis from the previous questions.

Solution Answers may vary. Example solutions may include the following diagram with the distances between processing steps shown in kilometers:

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8-27

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.28 Note any important assumptions and considerations you will make to begin the greenhouse gas analysis. Note: This response may evolve over time and change as you perform the analysis.

Solution Answers may vary. Example solutions may include the following: In this analysis it will be assumed all overseas transportation is via ocean-going cargo container vessels. Intranational shipping will be assumed to be via 18-wheel truck on highways.

8.29 Describe the expected limitations required to begin the greenhouse gas analysis.

Solution Answers may vary. Example solutions may include the following: Only transportation is considered in this analysis. Energy associated with raw material extraction, refining, smelting, and manufacturing is omitted. In a more thorough analysis these energy uses would be included and in fact may be greater than the energy associated with transportation. However, that energy could be considered separately by also examining the embedded energy associated with each material.

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

8-28

Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.30 Determine the impact your company would have on greenhouse gas emissions. Use Table 8.2 to estimate CO2 emissions associated with the transportation for a year’s worth of flyfishing rods. At a minimum, include an analysis for the following: a. Transportation by truck b. Transportation by boat Solution Answers may vary according to the mass of components chosen. Example solutions may include the following: Carbon footprint of the bamboo rod blank: Carbon footprint of the Bamboo Blank

= Mass of Bamboo (kg) × Wood − Kiln Dried Embodied Carbon �

Carbon footprint of bamboo blank = 61 (kg) × 0.3 �

Carbon footprint of the rod blank transportation:

kg − CO2 � kg

kg − CO2 � = 18.3 kg − CO2 kg

Carbon footprint of the Bamboo Transport Distance by Sea (km) kg − CO2 = × Boat/Ship Embodied Carbon � � 1,000 1000 − km kg − CO2 Distance by Land (km) × Truck Embodied Carbon � � + 1000 − km 1,000

Carbon footprint of the Bamboo Transport 11817 (km) kg − CO2 48 + 148 (km) kg − CO2 = × 0.03 � � + × 0.21 � � 1,000 1000 − km 1000 − km 1,000 = 0.61 k𝑔𝑔 − 𝐶𝐶𝐶𝐶2

Fly Rod Part

Material

Rod Blank Grip Handle

Bamboo Portuguese Cork Aluminum

Reel Seat Insert/Hardware Guides

Wrapping Thread Finish Complete Fly Rod

Stainless Steel – Chrome Finish Nylon Fiber Tung Oil Total

CO2 footprint of Component (kg-CO2) 0.61 1.08

CO2 footprint of Transport (kg-CO2) 18.3 3.06

Total CO2 Footprint (kg-CO2) 18.91 4.14

2.28

1.70

3.98

0.93 1.10 0.82 6.81

43.10 2.19 1.68 70.02

© 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

44.02 3.29 2.49 76.83

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

8.31 Create a visual aid to illustrate the impacts of transportation of materials in your rodproduction process. Use the output to show your results to create a visual illustration of the emissions of CO2 and the embodied energy of the fishing rod.

Solution Answers may vary. Example solutions may include the following:

8.32 The most important part of this assignment is to accurately portray the results of your analysis. This is what your grade will be based on (not whether your rod is more “environmentally friendly” than another team’s design.) Create a short video presentation.

Each member of your group should contribute to the presentation graphics and narrative (voice). Also, feel free to use and build on previous submissions and data collected earlier to tell the story of sustainable design. a. Describe the goal and scope of your analysis. What are the starting points and end points of your analysis? What are you hoping your analysis will illustrate? b. Provide a visual overview of your design. c. Illustrate the pathways of energy flow and material flow for the design. d. Report the major embodied energy components associated with your design. e. Illustrate the steps modeled in your assessment. f. Provided an interpretation of the impacts associated with your design. g. Describe the limitations and important assumptions in your analysis.

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Solution and Answer Guide: Bradley A. Striebig, Discovering Engineering Design in the 21st Century: An Activities-Based Approach, 1e, ISBN: 9780357685204, Chapter 8: Life Cycle Thinking: Understanding the Complexity of Sustainability

h. Describe the benefits (economic, environmental, and social) of your design and describe how these have been addressed using evidence summarized above. i. List any appropriate references.

Solution Answers may vary.

Excellent

Good

Answers correctly address each topic a - i for each category in performance, environmental impacts, costs (economic impact), and use (social impacts)

Answers correctly address each topic a - i for two categories in: performance, environmental impacts, costs (economic impact), and use (social impacts)

Needs Improvement Answers address each topic a - i for some categories in performance, environmental impacts, costs (economic impact), and use (social impacts)

Poor

Unacceptable

Answers partially address each topic a - i for only one in performance, environmental impacts, costs (economic impact), and use (social impacts)

Answers misidentify factors affecting material choice and do not address most categories of performance, environmental impacts, costs (economic impact), and use (social impacts)

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