openME 54.1

December 2022

December 2022 - “Scaling up”

“Scaling Up”

TECH: WOMEN IN ME

EDUCATION: BACHELOR COLLEGE 2.0

ASSOCIATION: INTRO RECAP

SIMON STEVIN SYMPOSIUM Engineering the sky

30-05-2023

08:30 - 18:30

Thanks to the state-of-the-art technology, unmanned devices can travel greater distances and remain there for longer periods through intelligent navigational systems and remote sensing. These capabilities are largely attributable to the work and technical know how of aerospace systems and engineering field overall.

In this years symposium we will take a look at the manufacture and design of space vehicles, satellites, space capsules, planetary probes, missiles and rockets.

Why attend the Symposium?

- Establish contact with companies - Talk to the professionals - Learn about the latest developments

FOREWORD Dear reader, The first quartile has passed, and we are amid the second quartile. We are just getting used to a life without lockdowns, but just as these troubles eased, new challenges arise. From global issues & conflicts to the housing problems we deal with here locally, things never seem to get back to normal. But one thing that is back is the release of the openME. Whilst you have been studying, teaching or doing other important work to improve the world around you, we as the editorial committee have been very busy making the first edition of the 54th volume of the openME. I want to thank the committee and all the people that wrote articles for this edition. Thanks to them we have an edition packed full of interesting articles to read.

In this edition, we take a look at various scales of things: from the smallest highest precision engineering to the largest structures known. Furthermore taking this scale into historic account, what once was a large leap can these days be a small uneventful step. Next to that, we also take a look at some smaller and larger objects of the Association, and of course, the usual articles about education are also still present.

I wish you a lot of reading pleasure!

With Kind regards.

Ben Gortemaker Editor-in-Chief

COLOFON

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December 2022, volume 54, issue 1 The ‘openME’ is a publication by the study Association for Mechanical Engineering Simon Stevin of the Eindhoven University of Technology Editor-in-Chief Ben Gortemaker Design Maartje Borst, Rik Lubbers, Roelof Mestriner, Joel Peeters, Lex Verberne Layout Jankatiri Boon, Ruben Bravo Veldhuijzen, Mart de Bruijn, Veerle Bus, Imke Goofers, Ben Gortemaker, Daniël Kleinjan, Ryan Leal, Kim van Loon, Remco Martin Lizandara, Martijn Zoer.

Editorial committee Ruben Bravo Veldhuijzen, Mart de Bruijn, Veerle Bus, Imke Goofers, Ben Gortemaker, Daniël Kleinjan, Ryan Leal, Kim van Loon, Remco Martin Lizandara, Martijn Zoer.

Illustrations and Pictures Editorial committee, Photo committee, source stated otherwise Printing office Drukkerij Snep Circulation 1000 pieces

Contact Eindhoven University of Technology Traverse 0.34 Den Dolech 2 5612AZ Eindhoven Post office box 513 E-mail: redactie@ simonstevin.tue.nl Homepage: simonstev.in

FEATURED INTERNSHIP SWEDEN

INTRODUCTION WEEK RECAP

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FEATURED

TECH

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10

Microdrones

5

Intership Sweden

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Slide rule

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Meet the new dean

29

Antonov

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39

Liberty Ships

BEP: Local mesh refinement

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Evolution of theme parks

23

Types of DBL people

63

Angkor Wat

33

ProtoZone

37

Redesign Bachelor College

45

BEP: Dual-phase steel failure mechanism

53

Internship NTNU

58

Meet the new manager of ESA-ME

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41

INTERNSHIP SWEDEN

For the final three months of his master Freek went to Sweden for his internship at the University of Lund.

INTRO RECAP

A look back at the introduction week from the perspective of the introduction committee.

REDESIGN BACHELOR COLLEGE

In the academic year 2022-2023 the bachelor college 2.0 will start, were the redesign of the bachelor college will be implemented.

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EDUCATION

PROTOZONE

Gemini south is getting rebuild and the facilities had to be moved, which was not an easy feat. But the new ProtoZone has given students the space to work.

SCALING UO WOMEN IN ME

PROTOZONE

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CAREER

ASSOCIATION

SPONSORED BY

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Team Polar

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Eigenfrequency of..

TU/e Mechanical Engineering

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Settels Savenije

18

Intro recap

25

Hehptig: Record breaking bikes

31

Women in ME

35

Lustrum photos

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Staut: The life of Ching Shih

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Grind my gears

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Puzzels

Settels Savenije

Education

INTERNSHIP SWEDEN

Burning Batteries

WRITTEN BY FREEK JANSEN

A year and a half back, it became clear I would be able to finish all master courses, leaving only the internship and the master graduation project to wrap up my study.

Given the COVID situation, I immediately signed up for the option to swap these two parts of my program, as I intended to do the internship in a country abroad. So here I am now, in Sweden, for the final three months of my master, doing an internship at the University of Lund!

Let’s start at the beginning. The bachelor introduction week in Eindhoven. For many an unforgettable week where you meet the university and its people for the first time. For me it was already the fifth time as a parent. The program is the same as always. Five days of partying, then about a week of recovering, right? Wrong! My ambitious self has planned my departure on the Friday evening of the introduction week, a choice that I have come to highly question during my preparations for leaving that very same day. After successfully finishing ‘DoorhaalVrijdag’ of the introduction week, my bus arrived in Kopenhagen on Saturday morning, where my mother was waiting for

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me. For a week, we did some travel in Sweden together.

I went as far as the large city Gothenburg, another great destination for students in Sweden. Through various places land inwards, I eventually made my way back to the final destination, Lund, after which I sent my mother back home again. Although during the first 6 weeks I actually found myself a home just outside of Lund in a nearby small town. About all my sightings in Sweden and my travels I will tell you about later, let’s first start with which I will be busy most of my time here, the internship!

Education

After my graduation project focused on numerical iron combustion, I am now keeping myself busy with something different, although also similar in certain aspects. To improve the safety of primarily electric vehicles, but also smaller devices such as smartphones or other household electronics, it is important to study the effects of ‘thermal runaway’ in a lithium-ion battery cell. One might remember the catastrophes of the Samsung Galaxy note 7, which could explode or set aflame due to a malfunctioning battery. Additionally there have been various cases of electric vehicles that were ignited by a failing battery system, either by mechanical failure as a result of a crash, or, fortunately less often, at random. When a battery cell gets damaged, the internal components can react with one another together with short-circuiting, which in the worst case results in exothermic reaction heat. Given that an electric vehicle consists of hundreds of battery cells, a single cell failure could quickly spread through the entire pack, similar to the domino-effect. Given that a single fully charged battery cell could already release plenty of heat for a small fire, the entire back bursting into flames will be catastrophic for the car and the safety of the passengers. Studying the effects of thermal runaway can help to mitigate the spread of heat through the battery pack, containing the malfunctioning cells, without compromising the performance too much. My project is mainly focused at the modelling of such a cell, in order to study the runaway to neighboring cells.

So how to approach this phenomenon numerically?

Ultimately, it would be beneficial to model a 3D battery cell that undergoes the thermal runaway process, after which flames burst out in every direction, heating the cells nearby. Additionally, heat transport through conduction and convection should be included as well.

One can imagine however that modelling the process in 3D can be quite expensive in terms of computation power. To be able to model a three dimensional battery with chemical reactions happening within can be quite extensive already. The accurate modelling of flame propagation after a cell bursts not only adds to the complexity, but might be very ineffective due to its random, explosive nature. Every simulation is unlike the previous. One can argue that given these difficulties, it can be more interesting to start small, with a rather simplified MATLAB (Simulink) model. We first consider a cylindrical battery with a diameter of 18 millimeters and a height of 65mm, often going by the name “18650”.

This is slightly larger than an AA battery. The equation in simple terms can be written as

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Education

here Q­’heat is the heat generated by the battery, mb the battery mass, cp the specific heat, hc the convective heat transfer coefficient, Ac the convective heat transfer area, Ta the ambient temperature, Tb the battery temperature, k the conductive heat transfer coefficient and dx the thickness of the conductive material. Finally Tb2 here would refer to the adjacent battery. The battery temperature is considered homogeneous, which is an acceptable assumption, given the dimensions of the battery. By defining the conduction properties of the battery insides, the Biot number (< 0.01) is used to verify this assumption. The modelling now requires a kinematic aspect that defines the release of heat during the thermal runaway process. This is slightly different from other combustion simulations, that are often based on kinematic mechanisms that describe the reactions between the various molecules present.

For batteries it is not that straightforward, and the reaction heat is directly taken from experimental data. By measuring the temperature over time during the actual ignition of a battery cell, one can determine the rate of temperature change over time. This rise in temperature can give an indication on the heat released, as the battery mass and specific heat are known quantities. This experimental data can then be used in the numerical model to give an expression for Q’heat, parameterized by the battery temperature.

In the figure 1 a graph is shown for a single battery cell.

This cell is heated up by a constant heating power of 20W, resulting in a nearly linear increase in temperature. At a temperature of about 500 degrees Kelvin, you can see the

Figure 3: Malmö

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Figure 1: fitted model thermal runaway process kicks in and the temperature exponentially increases in a short amount of time. Then at around 900 degrees, the burning process is finished and the cell continues to cool down due to convective and conductive heat transfer with its surroundings. Now lets increase the cells, to include the heat transport in between multiple cells going into thermal runaway. The roster below represents a total of 16 cells. At t = 0, the green encircled cells are heated. Through interaction with adjacent cells, the heat is transported and the domino effect kicks in in all directions. A true fire hazard has suddenly presented itself! Although I am burning batteries

Education

Figure 2: Picture showing the temperature in a grid of 4 by 4 cells at three different time intervals. The green encircled cells are being heated manually during the week, most weekends I tend to burn some calories. Lund is located in the very south of Sweden, just 20 km north of Malmö. In fact, within 45 minutes you can already be in Copenhagen. Lund houses a large university, which results in over 40% of the entire population here being students (!). The center is nice, small and cozy with plenty of opportunities to relax after a week of studying.

But of course, Sweden itself is all but small and cozy.

Travelling to Gothenburg felt like a journey from Eindhoven to Groningen, but at that point I have only just left the very southern tip of Sweden. Gothenburg itself is a very large city (2nd biggest city in Sweden after Stockholm), with an interesting bunch of small islands just off the coast. The contrast with the much smaller Lund is huge, but nevertheless the center was perfect for a fika (coffee + cookie). Malmö was much more comparable to the larger cities in the Netherland, with

some interesting architecture. The Mechanical Engineers with some ambition in Build Environment might be especially interested in this twisted tower. With a trip planned for the southern part of Sweden, to Copenhagen and to Stockholm in November, I intend to keep myself busy! Not to mention the widely stretched national parks that can be found all around Sweden. With an average population density of about fourty times smaller than in the Netherlands, untouched forests and large open fields can be found everywhere. But the exotic pieces of nature are not limited to the national parks. When arriving at my place in Lund, I can still speak Dutch to a fellow parrot! Although to be honest, I think neither of us can understand each other.

Figure 4: Gothenburg

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Tech

MICRO DRONES WRITTEN BY REMCO MARTIN LIZANDARA

An unmanned aerial vehicle (UAV), more commonly known as a drone, is an aircraft without any humans on board. Drones are one of the most fun toys for people interested in technology. There are so many different drones but the most well-known drones are the ones used for races and the ones that are used for filming. But drones are also used for many more purposes. The 2 types of commonly used Drones are human controlled and autonomous flight drones. The range of drones is wide from the biggest weighing 8000 kilograms to small drones. But what are the smallest drones in circulation?

History Of Drones The earliest ideas of unmanned aerial vehicles were presented in 1940. It was presented as a combat drone to fight in the Second World War. It was considered a massive advantage to bomb the Germans while not endangering any allied soldiers. In 1971 the first modern drone was made by a model airplane hobbyist, he drew up plans and DARPA ( Defence Advanced Research Projects Agency) built two prototypes. These prototypes were powered by a modified lawn-mower engine and could carry a 13 kg load for two hours. The first time drones were used in war was in 1973. Israel used unarmed target drones to spur Egypt into firing its anti-aircraft missiles. Before deploying their own pilots. The mission was an astounding success with no injuries to any of the Israeli pilots.

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After this successful mission drones were used in every war since. The first full-on UAV war was the first Persian Gulf War. According to the Department of Navy of The USA: “At least one UAV was airborne during Desert Storm”. The development of drones was from surveillance and diversion to combat. Drones were fitted with weaponry and in 2001 the first kill was reported by a UAV, in Kandahar. In recent years the USA has increased its drone strikes as part of the War on Terror. In 2015 it was reported that at least 6.000 people were killed by drone strikes.

Since 2012 drones are commercially available, and after that, the market has rapidly grown. The market has an approximate value of 10 billion dollars. Commercially available drones are mostly used for photographing and videoing difficult-toreach places or getting shots that normally were only possible by having a high budget. Companies like Amazon are trying to have drones deliver their packages. And companies like Esso are using drones to search for leaks in their setups, to increase the safety of the powerplants where they are working. Commercially available drones are used in Ukraine to help them defend their country. Drones are bought for approximately € 2000 and a small explosive is placed underneath it. Then they search for a Russian tank that cost approximately 5 million and is dismantled by such a simple solution.

Tech

How small can we go?

In Warfare and espionage, it is extremely helpful if your drone is not detected by the enemy. A smaller drone could be the answer.

All drones previously discussed are rather large, but there is a UAV that is extremely small: the Black Hornet. It is the smallest Military drone in use. It weighs less than 33 grams, it has a removable mission data SD card and upgraded graphic control systems. The rotor diameter is 123 mm and the total length of the drone is 168 mm. This drone has a range of an impressive two kilometres and has a maximum flight speed of 21 km/h. It has an endurance of 25 minutes of flight time before it needs to recharge. This drone can automatically return to your location and is also able to be controlled remotely. It is one of, if not the best drone that is available for espionage. But it is limited to going even smaller due to the rotors and motors that have to be in the drone. So can we go even smaller?

The wingspan drones are still not the smallest flying humanmade structures. Microfliers could be the smallest we can realistically go. Microfliers are small microchips, the size of a grain of sand, that can fly. This is not done by engines. Instead, they catch the wind and spin like a helicopter through the air.

These kinds of Microfliers are based on the maple tree seeds that slowly glide through the air. By replicating the maple tree seeds the microchips will be able to monitor air quality and the spreading of viruses. If that ever becomes a problem again.

It is speculated that wingspan drones are the future of drone production. They are more easily usable than the microfliers in less controlled areas. The biggest problem they still have is the batteries to get them working on that scale.

Biohacking

With a mass of only 80 mg and a wingspan of only 3 cm, we went even smaller with the Flapping wing robot of Harvard.

The flapping speed of the wings is a maximum of 12Hz. This drone can flap its wings independently. The wings are currently powered by a laser and it takes less power to fly this bee than it would take to light a single LED bulb. This means it is not yet market-ready. A new power source is needed to make this kind of drone workable. Inventions such as solid-state batteries and graphic capacitors could be the answer needed to make these micro drones in the future. But more innovation is required.

In the 1960s the CIA came up with a weird idea. They wanted to use a cat to spy on the Soviet embassies. A microphone was implanted in the cat’s ear canal, a small radio transmitter at the base of its skull, and a thin wire in its fur. The idea was, that cats go where they want and it is not suspicious if a cat wanders in some random rooms. Project Acoustic Kitty was born and $20 million later the plan was set up. The biggest problem they could not control was where the cat went. $20 million down the drain, but what if we can control cats, dogs, or even smaller animals?

Researchers at Rice University have shown how they can hack the brains of fruit flies to make them remote-controlled.

Within a second of a given command to its brain, the action was performed. The flies were genetically engineered by giving them some heat-sensitive ion channels in some of their neurons.

When the heat was sensed it would activate the neurons that caused the fly to spread its wings. The flies were kept in a small cage, when a magnetic field was turned on the ion channels would activate and a remote-controlled fly became a reality.

Being able to remote control small animals would give a whole new dimension on the uses of drones. The question that arises is whether remotely controlling a fly is the same as making a drone. Where is the line to call something a drone? To be honest, I don’t know how far we can go, but one thing I do know is that in times of war the weirdest ideas are tried to get a technological leg up on the enemy. This time it is a fly or a cat, however, trying to remote control animals won’t be the last time it is tried in history.

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Education

MEET THE NEW DEAN OF...

ME DEPARTMENT WRITTEN BY PATRICK ANDERSON

Dear readers of OpenME, The new academic year has just started and as the new Dean of the Department of Mechanical Engineering, it is my great pleasure to introduce myself. I guess most of you were or are enrolled in our BSc program and know me from the first-year course Introduction Mechanical Engineering and Truss Structures. For a long time I have been teaching this course and I really love the style of interaction in teaching you make possible. Here I try to combine different styles of teaching using slides, live demo’s for example with the pallet jack, lawn blower or tensile testing equipment combined with theory worked out on the board. And it is simply a lot of fun. Both ways I hope. As a Dean I have to reduce several teaching activities, but not Introduction ME. For me this is the perfect way to get in touch with all students!

Quite some firework at the start of the academic year. During the opening, where ASML CEO Peter Wennink gave a lecture, it became clear how much growth of our university is asked for by the companies in the Brainport area. Some companies plan to double or quadruple in the next seven to ten years. Close to 80% of all employees in those companies are trained in Brabant and Brainport is asking the University to scale and grow as well.

Our Executive Board is working on a strategy to enable such a growth while not sacrificing excellence in research and education.

The Department of Mechanical Engineering is in great shape. Our researchers are international well known and we have strong educational programs in the BSc and MSc. Historically we have strong ties with the industry and we are exploring options to hire hybrid teachers as one of the options to enable growth, in particular for our MSc programs. We are at the crossroad coming out of a period of isolation and online teaching due to COVID into an exciting path of growth, interaction and many on-campus activities.

Social safety and providing a diverse and inverse working environment clearly must be safeguarded for every student and employee of our department during the journey.

As a teacher and researcher I have always embraced an open-door mentality and as a Dean I plan to continue this. So, if you have anything you would like to share, criticise, or have suggestions or even compliments, please do so and drop by!

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Education

Bachelor Final Project

Local Mesh Refinement via Python and SU2

Last year, I did my bachelor end project within the Power and Flow research group under the supervision of Nijso Beishuizen. The project was focused on creating a Python script that could locally and adaptively refine a mesh from the SU2 software the group uses for their Computational Fluid Dynamics analyses.

WRITTEN BY FEMKE VAN DEN ELZEN

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Education Introduction

SU2 is open-source software developed in 2013 to provide a free alternative for the existing, often expensive, CFD (Computational Fluid Dynamics) analysis tools. It is mainly based on C++ and has been extended over the years with Python codes. It is predominantly used for internal and external flows, heat transfer and combustion, and for instance, the air circulation around aeroplanes or liquid pipe flows. SU2 is a finite volume solver designed to perform Partial Differential Equation analyses and solve PDE-constrained optimization problems with CFD. However, it is extensible to treat arbitrary sets of governing equations such as potential flow, elasticity, electrodynamics, chemically-reacting flows, and many others.

One of the required input files for the CFD simulations is a mesh file. Such a mesh is preferably uniform and structured, because structured meshes are often of high quality, leading to better convergence and lower errors. Often, meshes are unstructured because they are easier to create for complex geometries.

The local cell size determines the discretization error, and in simulations, the choice of cell size is determined by a tradeoff between computational time and accuracy. Choosing a very small cell size will result in an accurate analysis, however, it will have a large computation time. Choosing a very large cell size leads to a mesh with fewer cells and a smaller computational time, however, it will have a greater error. A solution for this can be local mesh refinement. When applying local mesh refinement on a coarse mesh, only the cells that have the largest impact on the solution and/or lead to the largest reduction of the error, are refined. Thereby keeping the computation time low while increasing the accuracy of the analysis. This project focusses on creating an adaptive mesh refinement algorithm implemented in Python that will perform a local mesh refinement based on the solution data exported from SU2.

aspect ratio and the face-orthogonality the optimal value would be 1. Because the mesh quality has a significant influence on the quality of the final results, each new mesh was analyzed on those three criteria.

Determining the refinement method

To determine the most optimal refinement method, a simple mesh consisting out of 13 cells with all an optimal mesh quality was created, both for a square and a triangular mesh. In each

Figure 1: Aspect ratio, skewness and faceorthogonality of a triangle small mesh, the middle cell was refined according to one of the previously determined methods. There was one problem to deal with. The SU2 software cannot handle hanging nodes. Hanging nodes are points on an edge of a cell that are not the corner points of that cell. Hence, some of the neighboring cells of this middle cell had to be refined as well. From the mesh quality analysis it became clear that option c for the triangular and option b for the square mesh would be the most optimal. These results were verified using a second mesh with non-optimal cells dimensions.

Mesh Quality

A mesh needs to be of sufficient quality for it to give accurate results. In the case of a 2D mesh, this quality can be analyzed using the aspect ratio, skewness and face orthogonality. The aspect ratio, is the ratio between the longest and shortest edge.

If the difference in edge length becomes too large, the model will become less accurate and hence the edges must be as close to an equal length as possible. The skewness can be described as the difference between the actual angle and the most optimal angle. For a triangle this would be 60 degrees and for a square this would be 90 degrees. For a cell, the least optimal skewness will be taken as the skewness of that particular cell. Next to this, the face orthogonality is determined. Now, the angle offset between the perpendicular vector to the edge, the blue vector, and the vector form the center of the cell to the middle of the edge, the red vector, is determined. A remark has to be made here. For the skewness, the optimal ratio would be 0 and for the

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Figure 2: Refinement methods for both rectangular and square cells

Education The algorithm

Based upon the results of the two separated meshes, the final refinement algorithm was made. It is divided into six steps through which I am going to guide you. As a first step, the cell that has to be refined needs to be determined, in this example the three pink cells. Then the algorithm will start by refining the quadrangular cell with the refinement method previously determined. Then the neighbouring cells of the triangular cells will be determined. If a particular cell is neighbour to two pink cells, the cell will be added to the list of to be refined cells. This is done to prevent any error for when later removing the hanging nodes. If such a cell exists in the mesh, the algorithm will start again at step 2 until there is no overlap in neighbouring cells anymore. Then the algorithm will move on to step 5 where it will refine the pink cell. And then finally the hanging nodes will be removed accordingly.

Figure 5: locally refined mesh of a close up of a tesla valve

This whole algorithm has been converted into code and to make it as user friendly as possible, an user interface has been made.

Figure 3: Refinement algorithm illustrated by a small mesh

Figure 6: original mesh in a closeup of the tesla valve Validation of the code

To show and validate the working of the code, a demonstration will be done on a Tesla valve flow simulation. A Tesla valve, or valvular conduit, is an invention created by Nikola Tesla in 1920.

It is essentially a tube that is designed in such a way that the flow in one direction experiences significantly less resistance than flow in the opposite direction. This is due to the implemented loops.

For the analysis, only a single segment of the Tesla valve was simulated. The mesh was created with 5 different grid sizes, varying from 12121 cells up to 99572 cells. Next to that, two locally refined meshes were made using the algorithm. These results were analyzed. No clear conclusions could be drawn from it. This could be the result of various different factors such as the mesh quality, the location of the measurement, or the refinement criteria. Because of the time limitations of the project, no solution could be found in time.

figure 4: Flow in a Tesla valve

However, to still show the working of the algorithm, a close up was taken. There could be seen that the algorithm indeed does refine the cells it was assigned to refine. Thereby validating the working of the code.

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Association

THE EIGENFREQUENCY OF...

THE LOUNGE TABLE WRITTEN BY BEN GORTEMAKER

We as an Association own many things, some of them quite new and shiny, and a lot of them have a lot of history. For those who don’t already know this rich history, we will tell you a bit more about it. But most importantly, in this column we will answer the question of what the eigenfrequency is of these wonderful objects.

In this edition of the openME we will take a look at three of our most priced possessions from small to large. Starting with the lounge table in the center of the lounge chairs and couch. This table has been given to us by the forty-fourth Board of W.S.V. Simon Stevin. Making it more than twenty-two years old, which is older than many of the current editors.

Top Left

Right

Bottom To measure the eigenfrequency of the lounge table we will excite with varying frequencies and look at which frequency the response is the highest. The excitation will be done in two directions transverse and longitudinal directions as can be seen in the figure bellow. We will ignore the other directions as those are too rigid to measure with our current’s methods. On top of that we will take a look at the different locations and compare if there is a difference in which location you excite the lounge table at. The results from this experiment are as following:

Location

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Longitudinal (Hz)

Transverse (Hz)

Top

3.5

5.0

Left

3.3

4.3

Bottom

3.8

4.5

Right

3.8

4.4

Tech

THE CALCULATOR OF THE PAST WRITTEN BY BEN GORTEMAKER

In this day and age, every engineer has a powerful computer in hand reach at all times. If it isn’t your TI84, laptop, Casio, or another cheap knock-off calculator, you likely still have your phone in your pocket to do some quick calculations. The luxury of having extremely fast, portable, and cheap calculators in your pocket is a luxury that has only existed in the past 50 years. What did engineers use back in the day, where there were no electric calculators to do their computations. Did engineers carry an abacus around all the time? Or have an expensive mechanical calculator? Or did they do everything in their head? You likely have never heard about it, but the calculator of an engineer back then was a slide ruler.

How does it work?

With its oddly shaped scale and moving parts a slide ruler is no good for measuring things like a normal ruler, luckily it is not designed to measure things, but then the question still stands: how can a slide ruler be used as a calculator? If you have paid attention to your calculus course you might remember how logarithms, and their special properties work. Logarithms have the unique property that if you sum two logarithms it is equivalent to multiplying the terms inside together and subtracting two logarithms is equivalent to division. Now back to the slide ruler, if you look a bit closer you might notice the fact that the scale is logarithmic, which as we now know can be used to exploit the additive property of logarithms to perform multiplications.

Now we know the basic functionality we can use it to do some multiplication and divisions. The first step is to put the 1 that is on the sliding part, also called the slider, on the number you want to multiply. Then go over to the number on the slider you want to multiply the first number by and read the value on the ruler and then you

have done your multiplication. To do division you do the above in reverse, you start by placing the number on the slider you want to divide by on the number you want to divide and then read of the value that is at 1.

Not only can the slide ruler be used for multiplication and division but also for computing ratios, squares, cubes, roots, trigonometry, powers and many other functions, really the only thing the slide ruler is not good for is addition and subtraction. This makes the slide ruler a very versatile and useful mathematical tool (at least in the time before electronic calculators), truly the only limitation was the size of your ruler and how accurate and sharp your eyesight was. Even though the slide ruler sounds like an ancient and low-tech tool it was actually the tool that was used by the NASA engineers for the Apollo missions, and even the astronauts on the moon landing had slide rulers with them. Making the slide ruler one of the most important mathematical tools in our history.

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Tech

History The origin of the slide ruler starts with the “Gunter’s Line” which was a single logarithmic scale that could be used to do multiplication. The “Gunter’s Line” was created around 1620 by the English theologian, mathematician, and professor of astronomy Edmund Gunter and within a couple of years the Englishman William Oughtred improved on his design by having the two logarithmic scales you could slide beside each other making it the first thing that could be recognized as the slide ruler we know today.

After its conception in the 17th century, many other variations were made for specific applications, but the technology did not spread very far from the borders of England. In 1859 the French artillery lieutenant Amédée Mannheim improved the slide ruler making it easier to use and more accurate. After that, the slide ruler really gained popularity at the end

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of the 19th century when the engineering profession became more and more relevant. And this popularity stayed, up until the 1970s when pocketable electronic calculators started becoming commonplace the slide ruler was the tool of an engineer.

In conclusion, if you ever find yourself in a situation where you have to do some calculations and the only thing you have nearby is a slide ruler you now know what to do. Or if you are in the attic rummaging through your grandparents’ stuff you might understand how one of those weird old things actually works. Or if you ever find yourself on an exam and the battery of your calculator runs out you can use a slide ruler as a backup or you just use it to confuse your fellow students and teachers.

Association

INTRO 2022: IMMENSE! The introduction week from the perspective of the introduction week committee WRITTEN BY DANNY LIU

A week full of partying, exploring and meeting new friends. That was the introduction week of 2022. Some of you call this week “fantastic”, others call it “the time of their lives”. But only one word can truly encapsulate this amazing week. This word is of course “ImMEnse” , the motto of the IntroCie 2022, the committee which organized this year’s Introduction week. For them, the introduction week was not only partying, but also a lot of organizing and hard work. Behind every intro activity, there were months of preparations. In this article, we will take you behind the scenes of every day of the Introduction week.

Monday The day started at 7:30 in the morning. We all gathered in De Weeghconst, and we were very excited for the Introduction week. We went through the schedule quickly, while eating our delicious breakfasts and then it was time for the preparations. The introduction week had begun.

IntroCie was responsible for giving the kiddo’s a good first impression of Mechanical Engineering and Simon Stevin.

We started with gathering and registering the kiddos and introparents in Atlas. Here, the introweek started with a presentation from the faculty and from Simon Stevin.

After we all sang ‘Het Simonlied’ together, the kiddos were divided into groups and were handed over to their responsible introparents. We made sure that every kiddo received some gadgets and an intro shirt.

Of course, the engineering skills of the kiddos had to be put to the test before they could become a true freshman.

So, it was time for the business case. Employees from Sioux came to give the intro-kiddos an awesome presentation, followed by a challenge to build a ballista from scraps. It was great to see the motivation and ingenuity of some groups. Although other groups were definitely better at decorating the ballista...

Afterwards, it was time for dinner and the day ended with an amazing party. All in all, a great start of the Introduction week!

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Association

Tuesday

Now, during the academic year, a normal Tuesday (probably) doesn’t consist of waking up hungover, pursued by happily throwing a bucket of water over your intro parents, taking a thrilling ride on the lustrumstunt and finishing the day with a barbecue and an epic party. This glorious sequence of events is commonplace during the introduction week. All these events were organized by our IntroCie. This meant we had a lot of work to do in terms of preparation and execution to realize this day.

The day started off with a university tour in combination with the testing of the ballista’s. Our committee had spent a good amount of time building a ballista testing construction. We designed a not previously used construction using a toilet flushing mechanism. Intro parents were forced to sit within the construction with a water filled bucket with a flushing mechanism right above their heads. When their introkiddos accurately shot at the target, the flushing mechanism was automatically activated and the parents would receive a lovely morning shower.

While some committee members were present during the ballista testing, others were already setting up the so called ‘green strip market’. To represent Simon Stevin, we had made a small chilling lounge decorated with a land yacht, sand and a swimming pool. As a bonus, we used the lustrumstunt as an interactive activity. During the market there was a short period of time for the IntroCie to take a break and eat lunch. We immediately had to go back to work however, as 500kg of loose sand had to be moved afterwards. A reasonable job, if you are aiming for a tremendous amount of back pain.

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Giving up was not an option though. We still had to set up a barbecue and an entire party with performances of DJDuckers and the world famous band: MAVO. This took a lot of work and we are incredibly thankful to the volunteers who helped us this day. After the barbeque was cleared away and the party was in full swing, IntroCie got to enjoy this awesome party and we got to look back on a successful day of hard work.

Wednesday

After two days of hard work, IntroCie got to relax a bit on Wednesday. The day started at 10:00 with a nice breakfast after which we started cleaning up the left-over stuff from yesterday.

In the afternoon, IntroCie disassembled the ballista’s and the testing construction. This is one of the moments where we would all shared a blissful feeling of accomplishment.

We knew that we had done a good job the last two days and disassembling the construction marked the end of a big part of our project. No better way to end this day then with a good party together.

Association Thursday

Friday

For a lot of people the Thursday was the most eventful day (or, rather, night) of the Introduction week. This is, of course, due to it being the famous doorhaaldonderdag, where everyone tries to make it through the night without sleeping.

Friday, the very last day of the intro. The day started early for some of us (well, the previous day had not ended yet due to doorhaaldonderdag). Around 09:00 we helped MAVO move their instruments to the main stage. After some hard work, it was time to chill. We once again gathered in De Weeghconst, which had become our second home by now. Some introkiddo’s and parents joined us. Now it was time for “entertainment De Weeghconst!” We had karaoke, watched movies and did both at once.

Our day started with helping E.W.D. Hephaestus arrange the ‘hangover breakfast’. Bacon, eggs and a nice glass of orange juice at 10 o’ clock meant people had time to take a nice breather from the partying the day before and get some energy for the long night ahead of them. During the breakfast, a large belly sliding course was created with the help of a winch and copious amounts of liquid soap.

After everyone had eaten, it was time for the main event of that morning: putting Mart (chairman of the 65th boar d) in a pillory and throwing a ridiculous amount of eggs at him. This tradition was of course kept hidden from the first-years until it was time to do it. Afterwards the committee did help clean up the Flux-field somewhat so that other people could set up their workshops.

In the afternoon all the kiddos could do workshops of their choosing, and after helping clean up the BBQs, the IntroCie enjoyed some nice naps and Disney films in De Weeghconst, until it was time for Eindhoven by Night, the bar crawl the Central Introduction Committee put out.

This marked the true start of doorhaaldonderdag. Not everyone remembers the entire evening, and not everyone managed to complete it, but there was no one who didn’t have a good time that night.

After catching up on some sleep and a delicious breakfast, it was time for the very last party of the week: All TU/ egether. The highlight was, of course, MAVO. Jens came up with a genius idea. The guitarists name, Van der Vleuten, sounds a lot like Van der Feuten. So, we all wrote a letter on our stomach and back and while they were performing, we all lifted our shirts to spell out Van der Feuten.

After the party, it was time to face the harsh truth, the Introduction week was over. We laughed together, cried together, were mad together and had fun together. All in all, an amazing week which we are very proud of. We hope that all introkiddo’s and parents had as much fun as we did and we are already looking forward to next year, when there is a new committee ready to take over.

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Career

Team

WRITTEN BY RYAN LEAL

One of TU/e’s interesting student teams is Team Polar. It was originally an Honours Academy team with six people in its first year. Over the timespan of three years, the team has grown to 28 people and is open to everyone that is willing and enthusiastic. They are a completely part-time student team, where it is expected to take ten to fifteen hours per week.

Team Polar’s mission started with Wilco van Rooijen, a Dutch mountain climber who has climbed the tallest mountains on every continent. He even climbed K2 without oxygen and almost died on that mountain, losing many of his toes. He came to our university with a small toy car with a solar panel and he said, “I want that, but in Antarctica.” And with that, the goal was to create an autonomous rover for researchers to collect data in Antarctica.

The research done right now in Antarctica is powered by kerosene-filled trucks. Each Artic fuel truck carries 7,918 gallons of fuel, and typically it is in these vehicles that expeditions for research take place. Fuel also powers the labs where all research collected on these expeditions are sent. A whole research facility may get shipments totalling to over 500,000 gallons of fuel during a threemonth warm period in Antarctica. In the remaining nine months, when traveling is too difficult, those gallons will have to be rationed for survival.

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This calls for sustainability: the first pillar in Team Polar’s mission. Sustainable energy is energy that meets the needs of the present without compromising the needs of future generations. At Team Polar, they envision a research vehicle free of the limitations of humans, which with human-present vehicles requires extra need of environmental control systems, and storage of human commodities like food, beverages, and sleeping arrangements. Creating a sustainable vehicle can help reduce the amount of fuel used on these expeditions, and even make the range for research expeditions — in practice — infinite. Additionally, using sustainable resources that do not emit CO2 emissions will reduce harm to not affect the environment with which they are studying. The way they approach this pillar is by considering solar-powered battery cells.

The second pillar to Team Polar’s mission is autonomy.

Driving in Antarctica is quite dangerous, as it cannot be easily known whether the ground you are driving along

Career

is stable. There can be layers of fresh snow that appear normal but beneath could lie deep cracks in the ice called crevasses. These can be especially unlucky, as getting a wheel stuck in a few meters deep crevasse can put a halt for some time on research collection. In even worse cases, these crevasses can be hundreds of meters deep, resulting in a loss of the whole vehicle and fatality of any researchers inside. Therefore, Team Polar’s rover is designed to detect these crevasses using GPR (Ground Penetrating Radar). These sensors can look into the ground and detect the previously mentioned small crevasses, and these sensors along with training a neural network on some already obtained crevasse data, can help the rover to redirect course under suspicion of possible danger.

The third and last pillar is affordability. In undertaking engineering, there are always designs that will be the most efficient, but presumably be the most expensive as well. For example, NASA uses gallium arsenate solar cells, as they are the most efficient today. However, if they were used in Team Polar’s rover these cells would account for 95 percent of its cost because it is so expensive. To tackle this, Team Polar is designing within the bounds of cost constraints; looking at the numbers so that it can be made as efficient as possible while also being generally affordable to manufacture and use.

One current challenge they have is maximizing the efficiency of their batteries. Batteries suffer under lower temperatures because there is a reduced capacity from lower kinetics and in the battery’s chemical reaction and increased internal resistance from the battery. Around sub -20 degrees Celsius, lithium-ion batteries cannot be reliably used anymore.

The autonomous vehicle of team polar To combat this, a heating system for these batteries are explored, or the use of other energy storage system alternatives all together. Examples of these are special types of batteries with a solid-state and liquified gasstate electrolyte that preserve reaction kinetics better at these lower operating temperatures. However, presently they are very expensive and not very commercialized.

The Team Polar rover now uses lithium-ion phosphate for the battery.

Team Polar has finished their first prototype’s complete exterior design and showcased it during the Dutch Design Week at the TU/e. They are almost complete in its interior and technical parts as well, planning to finish it in mid-November. By the end of November, they desire to perform initial tests on their rover so that in January of 2023 it can be taken to Norway for further testing.

INTERVIEW WITH LAURENZ EDELMANN

Laurenz Edelmann is an Applied Physics Master’s student in his third year. In his first year of his Master, he joined Team Polar through the Honors Academy.

He has been there since the beginning. He is currently the manager of Team Polar.

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Education

Different types of DBL people WRITTEN BY IMKE GOOFERS

The MATLAB genius, the planner and the silent one, we all know them: a DBL group consists of different people with a lot of different personalities. These seven types of DBL people will be very recognizable for you as a Mechanical Engineer!

The small task lover

The partyanimal

After the introduction round in the very first meeting of every DBL, you and your new teammates start discussing what the actual assignment for the DBL is. Most of the times, everyone is a bit confused: although it seems that a lot needs to happen during this DBL, you have no idea where to start and what the new SSAs need to be. Luckily, the RPC list and the planning are always a sure thing in these uncertain times. The small tasklover immediately jumps up when the SSA division takes place: this is his time to shine.

‘Why do they schedule a meeting on Friday morning?’ is a question the partyanimal asks himself every Friday morning. After having a great evening in the Peppers, which was so fun that – of course – a nice afterparty had to be visited as well, the hangover is real at 08:45 in the morning. Although the partyanimal feels a little like he can start to puke anytime soon, he gets himself together and goes to the meeting. Comforting himself with the thought:’ I have done this before, I can do it again’, he drags himself through the meeting.

The MATLAB genius

The planner

For loops, if statements and creating plots of everything, nothing and everything in between: the MATLAB genius will make it work. A DBL without a MATLAB genius is as biking with a flat tire: it makes life harder. What you would write in ten lines of code, this genius puts in one line. With a few clicks and changes, he easily improves the mistakes that were made by other team members as well. To every MATLAB genius out there, what would we be without you?

The project information document is the favorite file of the planner in the group. At the start of the project he has already marked every important deadline and put them in his agenda.

Handing in a deadline too late? That an absolute no go.

Completely trusted by the group on what the requirements of the assignment are and whether these are reached with the progress made: the planner makes sure everything is handed in on time.

The silent ‘Actions speak louder than words’ and ‘quality over quantity’ are the mottos of the silent in the DBL group. He maybe does not say as much as the other team members during the meeting, but when he does, it is always well thought through. Not only his quality comments contribute, his SSAs are of great importance as well. When the silent starts to feel comfortable in the group, he lives up and starts to speak words as well: with a lot of enthusiasm he tells about his own work and asks questions to others about theirs.

It is at that moment that everyone starts to see it: this is a great team member.

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Education The sneaky

The final report writer

For some, words speak louder than actions. During the meeting, the sneaky is making more comments than anyone else – quantity over quality. But as much comments as he makes during the meeting, so little work puts he into his SSA. For some reason, the sneaky exactly knows the bare minimum he needs to do in order to pass the course, often even with a good grade. We have to give it to him: it is an art.

A lot of different solutions were thought of during the project and a lot of steps were taken. Luckily, the final report writer exactly knows how to summarize everything together. From re-writing pieces of other team members to checking spelling and grammar: the final report writer makes sure that the final report meets all requirements and that the important messages are conveyed.

A DBL group is special. It is beautiful to see that a set of people with so many different characteristics can still form one group.

Which DBL team member are you?

FEEDBACK BINGO Sometimes, it can be quite hard to come up with original feedback. Can you get a bingo in your next DBL? 1.

FEEDBACK BINGO 2

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5

9

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10

13

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17

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1

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6

You were a bit silent this meeting, but you were minute taker, so that is understandable.

2. The board looks nice.

3. You had good input during the meeting.

4. You asked critical questions during the meeting.

5. Reread your SSA one time before you hand it in.

6. Your SSA was of good quality.

7. As a chair you can conclude things a bit sooner.

8. You were a bit silent this meeting.

9. You were minute taker, but you still had good input.

10. As a chair try to facilitate the meeting more.

11. You were very active during this meeting.

12. You could be more active during the meeting.

13. Do not be afraid to pick the more challenging SSAs. 14. Good that you ask for clarification when you do not understand something.

15. You are well prepared with your notes.

16. You are also active outside of the meeting.

17. Nice that you implement the feedback that was given to you.

18. It was nice to work together with you on the SSA. 19. Your SSA was a bit short.

20. Try to be on time next meeting.

21. Prepare questions and write them down in advance so that you can ask them during the meeting.

22. Nice agenda.

23. Your SSA had a nice structure.

24. Good presentation.

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Association

Hephtig:Record-breaking

bikes

WRITTEN BY FABIAN BOOTS

“Records are meant to be broken” is a saying everyone is probably familiar with. On the 8th of October, a 26-year-old record was broken. In 1996, Chris Boardman cycled 56.375 km in 1 hour. Filippo Ganna beat him by adding 417 meters to the record, accumulating 56.792 km. These 417 meters might not sound spectacular at all. However, the initial record was set using a time trial position which was banned straight after. Ganna has now beaten it using the latest technologies and aerodynamic advances, which is where it becomes interesting for us as Mechanical Engineers!

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Association

Weight and materials

Aerodynamics

Normal road bikes have decreased a lot in weight. As the courses are much less predictable, accelerations are very frequent and elevation plays a big role, weight becomes very important. The lightest bikes that can be created, weigh just over 4 kilograms. In a world where every gram matters this makes an insane difference!

However, the UCI (Union Cycliste Internationale) has instated a minimum weight requirement of 6.8 kilograms, as otherwise, the weight of bikes would become too light, compromising safety. In climbing races, the road to success is the wattage per kilogram which a rider can put out over several hours. Dragging an extra useless 2.2 kg of weight over many cols in the Alps or Pyrenees results in a much higher kilo joule expenditure, creating more fatigue in the later moments of day races and stages of stage races. This difference would neutralize any climber on the tour!

Even though climbing on a bike is a lot of fun and can get you to the most amazing and beautiful places, some riders think riding criteriums is even better. A criterium, or crit, is a bike race consisting of several laps around a closed circuit. Riding these short and hard courses with anywhere around 50 people, with speeds in the range of 45 km/h, creates an insane amount of adrenaline. In these races, aerodynamics is key, just as with the hour record.

For time trial bikes, however, weight is not as relevant.

In the hour record of Filippo Ganna, weight is almost negligible as both bikes have been designed for pure speed on a flat area. That makes stiffness much more important because all the energy which is put into the pedals needs to be converted to forward motion. In 1996, the bike was already made from carbon, which made it a very futuristic-looking bike. The standard frame material of superbikes used in that time of the Tour de France consisted of titanium, steel and aluminium. Next to that, the bikes were made from hollow tubes welded at the corners. Carbon, however, opens a whole new range of shapes and techniques.

This allowed frames to be engineered which provide much more stiffness, especially in a lateral direction.

It is not only important when accelerating, but also when holding speed. Which in turn is critical in the hour record! 26 years later carbon has become the standard and almost the only option used in superbikes.

Scalmalloy The new Pinarello Bolide F HR 3D is pioneered using a new technique which does not use carbon, but scalmalloy. A material which is made from scandium, aluminium and magnesium. It originates from the aerospace industry and is specifically designed for 3D printing. With 3D printing, even more, specific shapes can be created. It can also be used to reinforce critical points to make the structures even stiffer. Lastly, it can keep the material usage to a minimum, to decrease the weight as much as possible.

Both bikes have been engineered with one purpose in mind, which is to go as fast as possible for as many laps through the velodrome. Next to that, they have been tailor-made for the person riding the bike. The shape used in 1996 is probably more aerodynamic than the one used in 2022. However according to the UCI a bike nowadays needs a bottom tube. Therefore, Pinarello has created a bike which allows Ganna and the bike to have an as small as possible frontal area and CdA (coefficient of aerodynamic drag), mainly by placing the rider in the most optimal position. This means that the hands are placed close together in front of the face, where the head is in line with the back and the shoulders are shrugged in.

The cyclist on a bike can contribute as much as 80 percent to the aerodynamic drag. This aerodynamic drag is in turn around 90 percent of the overall drag, which makes it the most important factor to influence. To decrease the drag as much as possible, the illegal superman position was created.

This decreases aerodynamic drag drastically in comparison to the current legal aero position utilized

by Ganna, called the praying mantis position. To overcome this difference, an insanely talented cyclist is required and apparently 26 years of technological developments.

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Association

Coefficient of drag When looking at the CdA once again, the rider is most important. Tests have shown that skin is slow and fabric can be made which is much more aerodynamic.

When comparing both attempts, it is clear that Ganna is wearing more fabric than Chris Boardman.

Specifically on the arms and legs, which in turn are critical areas. Firstly, the arms and hands are the first parts that touch the air. Next to that, the legs are continuously spinning at high speeds creating much more turbulence compared to the upper body. Lastly, the teardrop shape is the most aerodynamic. The arms and legs, however, resemble a cylindrical shape, which has extensively been proven to be ineffective.

To compensate for the ineffective arms and legs, fabrics are made which keep the air attached to parts where it needs to be attached, and also the opposite if required. On the arms, shoulders and legs rougher fabrics are typically better than smooth fabrics. It follows the same logic as the texture on golf balls. The structure of the fabric adds turbulence to the surface airflow, which is called ‘boundary layer turbulation’.

For an athlete to be fast in cross-winds and benefit from a good sailing effect, what they are wearing needs to have a turbulent boundary layer.

When talking about aerodynamics, one of the final areas which cannot be ignored is the wheels. Just like the legs these are spinning at high speeds and creating turbulence. To decrease this as much as possible, disc wheels are used. Spokes in a wheel once again create a big amount of turbulence. Next to that, if air flows over the middle of the wheel, the rim disturbs the airflow after which it unifies again to hit the front fork and then gets disturbed again by the second part of the wheel. If a disc wheel is utilized, it can flow over the surface and will not be disturbed as much. This decreases the CdA value. There are also disadvantages to discuss. They impede steering capability on open roads, thus it is not recommended to utilize two disc wheels anywhere with crosswinds.

However, on a velodrome where the hour record is being held, there are no relevant cross winds, so disc wheels are the best option.

Rolling resistance Thus far we have concluded that bikes have been made stiffer, more aerodynamic and lighter. The final part to address is the remainder of the resistance, which stems from rolling resistance and drive train resistance. Tyres of course create most of the rolling resistance. For the tyres, the choice was made to go for the Continental Grand Prix 5000 TT TdF. They are 17 seconds faster over 40 kilometres than the already very good tires the Continental Grand Prix 5000 S TR, due to being 35 grams lighter and having more optimal thread thickness. It is hard to compare these to normal tires, but they generate approximately 7.6 watts of resistance, which is nothing in comparison to already very fast normal race tires.

Finally, for the drive train, the choice was made to go for the most aerodynamic and low-friction options possible. On the front, it had a 64-tooth chainring from Wattshop, which was paired with a 14-tooth in the back. They were connected by an Izui KAI chain. This setup is once again specifically tailored to Ganna. As a finishing touch, to decrease the friction even more, a special low-friction coating from the British company Muc-Off was applied.

Another area also influencing the CdA are the helmets utilized. Both Boardman and Ganna have helmets shaped to guide the air from head to back. By keeping the gap between the back and helmet as small as possible the least amount of disturbance is created on the top, which decreases drag. In both cases, this has already been done very effectively, which can be seen in the pictures.

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All in all, it can be concluded that the best technology has been used to improve the record. It can be assumed that the weight does not matter between both attempts. Next to that Boardman had a more aerodynamic position and Ganna had the better technology. Given these points, the conclusion might actually be that technology and aerodynamics did not make the difference, but talent of Ganna did. Many people have tried before with all the new technologies and only Ganna succeeded!

Association

THE EIGENFREQUENCY OF...

DEN DIS WRITTEN BY BEN GORTEMAKER

We as an Association own many things, some of them quite new and shiny, and a lot of them have a lot of history. For those who don’t already know this rich, history we will tell you a bit more about it. But most importantly, in this column we will answer the question of what the eigenfrequency is of these wonderful objects.

The next object we will take a look at is Den Dis. Den Dis is one of the oldest objects in De Weeghconst, as it has been given as a gift by the fortieth Board when De Weeghconst first opened in 1997. Den Dis has been there from the beginning of the Thursday drinks and still to this day accompanies us during the Thursday drinks.

1 2

4

3 The eigenfrequency will be measured in a similar fashion as the Lounge Table. Exciting it with varying frequencies and in the longitudinal and transverse directions. And of course we will also take a look at if the location of the excitation has an influence on the measured eigenfrequency.

The results from this experiment are as following:

Location

Longitudinal (Hz)

Transverse (Hz)

Top

2.2

2.5

Left

1.8

2.2

Bottom

2

2.4

Right

1.9

2.3

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Tech

GIANT OF THE SKY: ANTONOV AN-225

The An-225, the largest operating plane designed and manufactered by the Antonov Bureau With its wingspan of 88.4 meters, a length of 84 meters and a production cost of around 3 billion dollars, the Antonov 225 ‘Mriya’ is (or was sadly) the largest operating airplane in the world. The Mriya, which means ‘dream’ in Ukrainian, was designed by the Ukrainian Antonov Design Bureau in the 80s as a military plane with the purpose of transporting the Soviet version of the Space Shuttle for the USSR. This gigantic plane is powered by six large turbofan engines, each with the capacity to produce almost 230 kilonewtons of thrust. To keep all these engines running, 342,000 liters of fuel can be carried along a flight. All of this fuel is distributed evenly across both wings (to keep the center of gravity around the same spot). Moreover, the An-225 has a special landing gear system to carry the 285,000 kilogram weight of the plane. It consists of 32 wheels, of which 4 are in the nose gear (located in front) and the other 28 are aligned in pairs of two, left and right of the fuselage.

WRITTEN BY DANIËL KLEINJAN

Thanks to the rounded top of an airplane’s wing, air needs to travel a greater distance compared to the air beneath the wing.

This results in the speed on top of the wing being higher than beneath. As can be seen in Bernoulli’s principle, when the speed increases, the pressure must drop since energy is conserved at all times. Under the wing, the exact opposite happens: the speed is slower and thus the pressure increases. Due to this pressure difference, the airplane is pushed up.

How does an airplane fly?

Let’s start with a basic lesson on how airplanes are able to fly.

The simple answer: due to a pressure difference between the lower and upper part of an airplane’s wing. Because of this, an orthogonal force is created with respect to the fluid’s (which is the air) motion. This force is referred to as the lift force. In the second year of our bachelor, during the course ‘Heat and Flow ’, this concept is explained by means of Bernoulli’s principle

In order for this to work, the speed of the air to flow around the wings is required to be high enough to generate enough lift force.

For the An-225, six turbo fan engines are used. Additionally, this plane needs at least 3,000 meters of runway to be able to reach the required speed for a successful take off.

History and Operation of the An-225 During the time of the cold war between the USA and the USSR, both space programs were in a fierce competition. When the USA started operating with their space shuttles, the USSR developed the Buran (the Soviet version of the Space Shuttle).

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Tech

The goal of both spacecraft was transportation of payloads to space at a lower cost since a Space Shuttle has the ability to go to space as well as return to earth and land like a regular aircraft.

At the time, the USA was using the Boeing 747 to transport their own space shuttles, thus the USSR also needed a plane to perform the same tasks with their Buran. Therefore, the ministry of Aviation of the USSR asked the Antonov Bureau to design an aircraft that would be capable to transport such cargo.

Throughout this period, the Antonov Bureau was working on the design of the An-124, a plane that had the goal of transporting cargo. Initially, the design team thought the An-124 could be a potential candidate to fulfil the type of missions for the Buran program. However, when the engineers from the Buran Space Program concluded that the Buran would be much heavier than originally planned, it was decided that the An-124 was not suitable anymore.

Later in 1983, a proposal from the Antonov Bureau was drafted to use some of the elements of the An-124 to create a larger plane, that did have the capabilities that were requested by the Buran Space Program. Some of these changes were structural changes to increase the strength of the plane. Furthermore, the width of the wing was increased to be able to fit an extra turbofan engine on each side. In addition, the tail was changed. This was done due to the fact that when a Buran would be transported, its engines would be in the direction of the vertical stabilizer, according to the design of the An-124. Consequently, the tail was changed into a twin tail, consisting of two vertical stabilizers on both ends and horizontal stabilizers in the middle. After three and a half years, the development was finished and on November 30 1988, the plane rolled out of the hangar in Kiev. After ground tests, the plane took off and flew for the first time on December 20, 1988. Its first mission was on May 3 1989, when the Mriya carried the Buran for testing.

In the course of the next years, the An-225 fulfilled its purposes and was used for commercial flights to transport other cargo.

However, after spending no more than 671 hours in the air, the An-225 was (temporarily) placed in storage, not long after the collapse of the Soviet Union and the discontinuation of the Buran Space Program. During this time, the real profitability of the plane was doubted and therefore the plane was stored.

Then, a couple of years later and after restoration work, a new task was found for the plane, namely commercial cargo transport. In May 2001, the ‘second’ official take off took place.

The plane was used to transport the largest single cargo in aviation history, according to the Guinness Book of Records.

It even flew to Eindhoven in 2005 and 2008, with many people watching this giant land on our air basis.

The end of the An-225 Sadly, during the war in Ukraine, Antonov’s largest airplane was destroyed in a Russian attack on the Antonov Airport, near the Ukrainian Capital, Kiev. People went to the site to see the destroyed airplane filled with bullet holes and surrounded by destroyed tanks. The entire front section of the fuselage (including the cockpit) was destroyed, as well as parts of the right wing. The last commercial mission of the An-225 was in February 2022 with the objective to collect around 90 tons of COVID-19 tests and fly them from China to Denmark. Its final flight was back to Antonov Airport, where it was scheduled for maintenance. When the threat of the Russian invasion began to rise, the An-225 was prepared to depart from Ukraine, on advice of NATO. Unfortunately, on the day the plane was supposed to evacuate, the Russian invasion was launched with the Antonov Airport as one of its targets, which lead to the destruction of the plane. The rumor goes that Antonov Airlines, who were operating the An-225, were already aware of the danger but took steps to evacuate the plane too late.

The future Now the largest commercial airplane in the world has been destroyed, the question about whether the original plane is intact enough to be revised arises. Based on video research, the plane looks to be in too bad shape to be revised. However, experts from the from Antonov have not yet investigated the plane, resulting in the official status to remain unknown. On May 20th, the Ukrainian president Zelensky announced the attention to build a new Mriya in honor of the pilots who have died in the war. Furthermore, manufacturer Antonov has started a fundraiser to acquire money to be able to manufacture a new plane. To sum up, we will need to wait and see whether the giant of the sky will ever return to its full glory.

The destroyed An-225 at the Antonv Airport, Kiev Ukraine

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Association Els de Vaan-Bruinsma receiving her Bachelor diploma at the TU/e

SCALING UP WOMEN IN ME WRITTEN BY VEERLE BUS

Women in engineering have come a long way from where they began, however it is still not as normal to be a woman studying mechanical engineering as it would to be a man. In the 1960s, the famous ‘draw a scientist’-research was done. 5000 grade school children were asked to draw a scientist and only 28 of those drew a woman, of which all the 28 were drawn by girls. Luckily times have changed and by a recent study in 2018 it showed that more than half of the girls drew female scientist when asked to draw a scientist. This study shows that woman are scaling up within the industry.

Years back, the first ever female to receive a bachelors diploma in Mechanical Engineering was Stanny Koopman, in the year 1921 at the TU Delft. It took a good 45 years for the first woman to receive her bachelor diploma at the TU/e, for a study she did from start to finish in Eindhoven. Her name was Els de Vaan-Bruinsma and she received on 18 may of 1966 her diploma in chemical engineering.

She received her diploma twice, because the

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first one only contained male pronouns. After an excuse letter by the university she did receive a correctly formulated diploma. She was not the first woman studying at the university, as Henny van der Leeden started electrical engineering in 1957. She was the daughter of physics professor, and later to become rector magnificus P. van der Leeden. On her first day, the rector magnificus spoke to her and her year: ‘Mejuffrouw en mijne

Association

heren’, which is translated to ‘miss and gentlemen’.

Her apperaence was quite special this day and she even got to shook queen Juliana’s hand. This day she was the example for the many women who followed after her studying at the TU/e. However, she did not finish her bachelor, as she started programming the PACE-computer (a big analog calculator) in 1960.

Tu/e scaling up After the first woman had made their way into the male dominated world, the university itself started realizing that becoming more diverse was important. Plus, statistics showed that women who studied at the TU/e were performing better than male students at their study, as they had on average more credits each year. More than enough reasons for the TU/e to start actively recruiting new female students. The rates of women at the university were around 10-15% for quite some time, where some studies reflected more the gender distribution of society (like biomedical engineering and industrial engineering) and others not at all. Some nation wide campaigns were already running, but in the 1985 special information activities were organized for the first time. Those activities were a huge success, as more than 700 woman showed up. As a follow up to this, an exclusive pre-intro was organized for all new female students. They were able to get to know each other and to study. However, in September of 1987 the first criticisms arose about this, as the new women did not want such a special treatment. In the 1990s this emphasis stops and 1995 would be the last year that a special information event for women is organized.

Woman committee Being female when studying mechanical engineering is still not normal and is only 10% of the people doing the study. That is why years back, woman found it important to stick together and get to know each other better. This is when the Woman Committee was set up at the study association Simon Stevin. They organize several activities throughout the year, with the first one always being a delicious lunch. The whole committee show off their baking skills and make homemade goodies for new female ME student who would likes to join. This year, a special speed date edition was planned, to get to know even more fellow students.

Women Committee Ladies Lunch 20212022 Venilia Some female ME students took it a step further than just doing a few activities a year together.

They formed a sorority called Venilia which was founded on the 28th of February in 2018. They have four main goals, which are giving a place to females studying mechanical engineering and connecting everybody from all different ages. They make connections with other students within and outside Eindhoven, through integration drinks and they prepare themselves for the business life, that will be mostly male dominated. This is all done with a lot of fun and laughter, Venilia even has their own drink, which is homemade limoncello with a touch of vanilla.

While there is a lot of opportunity for females studying engineering nowadays, there are always people trying to involve even more women in engineering in the future. Associations like woman in STEM and SWE (Society of Women Engineers) connect people on a more global scale.

Some individuals, for example Debbie Sterling, try to make an impact themselves. Sterling found that most building or engineering children’s toys were targeted towards boys and she wanted to change that. So she designed a toy helping young girls improving their analytical skills, which was well received.

Women in (mechanical) engineering have come a long way since 1921. It has definitely not been easy for some, but they all made it easier for the women following them up and that is something to be grateful for. In the end, being the minority gives you quite some privileges that you can take advantage of. So hopefully the rise of woman in technology can continue and end up being a normality.

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Education

THE PROTOZONE

WRITTEN BY RUBEN BRAVO VELDHUIJZEN

Since the mechanical engineering department moved buildings to Traverse last year, The workspace at the basement of Gemini also needed a new home. Undeniably reallocating all the before available facilities was not an easy feat. But the newly finished ProtoZone on the second floor in Traverse, and under supervision of Michiel van Gorp is ready to give everyone new opportunities.

During a welcoming guide around the space we spoke to Michiel van Gorp and his assistant Bert Friedl to hear what ProtoZone is all about and what their vision is for the future.

What is ProtoZone?

If you take a look at the ME major curriculum, Design and Challenge Based learning goals are at the forefront of each student’s academical progression. Van Gorp took on the assignment to rearrange the newly acquired workspace and bring in all the tools students would need throughout their studies. Unsurprisingly, as soon as you enter it is obvious that workbenches are protagonists. Sturdy tables arranged in files along the length of the room, waiting for the next group of students working on a new crane, pump or robot.

When we asked van Gorp how students should see ProtoZone, he points out the lack of chairs and emphasizes that a workspace is there to build stuff. Performing tests or doing computer work should be done at appropriate places elsewhere. Luckily right outside in the hallway an array of office tables are a great place to work on simulations or CAD design without compromising your laptop fans to the possible saw and metal dust.

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Education

What changed compared to the workplaces in Gemini?

Answering to our curiosity about the equipment that was moved or left behind, van Gorp told us that with every rearrangement some things are bound to be lost or repurposed. As such the 3D printers that originally had their place at Gemini in the measurement room Sel, were now part of ProtoZone. On the flip side some heavy equipment had to be sold, that was either not being used or very antiquated. Nonetheless ProtoZone has plenty of cool tools now always accessible at one place.

Are students free to come work on own projects

As mechanical engineers it is only natural to crave working on your own projects in your spare time. And it this mindset should be encouraged more often if you ask Michiel van Gorp.

For this reason he decided that giving students the chance to ask for help and use tools from the workspace adds valuable experience to their development as an engineer. ‘What is the use of a new tool if you use it once and leave it sitting your

shiny toolbox’ he said, referring to all the knowledge students gather throughout their bachelor’s but seemingly leave unused as they move onto new challenges.

To grant the students interested in this kind of activities the options work at ProtoZone once in a while. Van Gorp has approached the Association to introduce a subscription portal to the simonstev.in web site where ME students can request joining one of the work evenings. Depending on how much demand there is and how much the academic schedule can allow these evening would be planned in some recurring fashion.

In the meantime while this is setup, emailing van Gorp is for questions and appointments is the way to go.

What does the future hold for ProtoZone Now that ProtoZone has opened to its intended capacity, it will stay this way for the foreseeable future. But of course will it have to evolve according to the needs of the department and the future goals of growing the ME major. With expectations of growing the student count to around double the current throughput in upcoming years.

Exposing students to different manufacturing methods is an important part to stimulate their practical intuition. Although there are no plans on the table to expand the current facilities, it is always in the back of the mind of the department’s organization. On the one hand what will be the needs of DBL courses still in development but also what useful skills outside the academic scope can be taught to future students. Manufacturing machinery have seen leaps of modernization in the last decades and having a basic understanding of their functioning is undeniably worthwhile. So, although purchasing machines that are expensive and difficult to handle are not a current priority. It is certainly the department’s ambition to offer the most complete education to their students with innovative practices and a safe working environment in mind.

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Lustrum XIII “In Geheughen Gestalt!”

1957 | 2022

W.S.V. Simon Stevin

Education

BACHELOR COLLEGE 2.0 WRITTEN BY ELISE VAN LIESHOUT

In the academic year 2022-2023, the Bachelor College 2.0 will start. This is a redesign of the current bachelor college in which some big changes are implemented. These changes mainly focus on the cancellation of the basic courses, which are the courses followed by all departments at the same time, as well as the introduction of challenge based learning courses. Next to this, the USE learning trajectories will be redeveloped and changed into two courses about the impact of technology, such as the ethical aspects.

* At this moment, October 2022, the new curriculum looks like this. However, some small changes can still be made over the years.

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Education

Core courses

One of the big changes is the cancelation of the core courses. In the previous curriculum, the courses Calculus, Applied Natural Sciences, Data Analytics, USE Basic and Engineering design were taught. In the new curriculum only calculus stays. The other courses are implemented in different courses, only the information needed within a specific department is now implemented in the courses. For our curriculum this can be seen in the new courses named Principles of design and programming and Statistics & Probability. Next to this, the USE Basic course will be partly transformed into the ITEC Ethics course.

The cancelation of these core courses makes room for an extra major course in the first year. This means that Signals and systems is now placed in the fourth quartile of the first year while it used to be in the first quartile of the second year.

CBL

Within the new curriculum, challenge based learning lines are implemented. The goal in challenge based learning is to have the students working in teams on an open ended project. The goal of the project becomes clearer when the student gets further into the project. This is achieved by acquiring new information and getting feedback.

For Engineering design, a new alternative is formed.

Engineering design is a design based learning project in which teams of students from multiple departments work on a project. In this way, they can combine their knowledge to find a solution for the problem. The goal is to have assignments from real life challenges. To achieve this, the goal is to have assignments coming from companies, the government or students. Within the new curriculum this project is transformed into a multidisciplinary challenged based learning course. The team will consist of students from at least two different departments.

USE learning trajectories

For the new curriculum, the USE learning trajectories are deleted and replaced by two Ethics courses. In the fourth quartile of the first curriculum an ITEC Ethics course is implemented as well as in the first quartile of the third year where an ITEC Advanced course is implemented. These courses will not only focus on the ethics side of the technology but also on the general impact. You can for example think of a lifecycle analysis.

The goal of these new courses is to find the connection with the user, society and entrepreneurship and the curriculum, which was missed in the previous USE learning trajectories. Some of the courses from these previous learning lines stay so the students can choose these in their free elective space.

Strategy 2023

This new curriculum is in line with the strategy of 2030 of the university. The main pillars of this strategy are: • •

•

Talent: on all levels, because talent makes or breaks our university.

Cooperation: our cooperation with the national and international industry, within the Brainport region, with our alliance partners, and at European level.

Resilience: we need an organization that fits our ambitions. We will continue optimizing and professionalizing our organization to enable the change.

In conclusion, the new curriculum is almost finished and some big changes are implemented so that the new curriculum fits within the strategy of 2030.

The last finishing touches will be implemented in the upcoming period so that the new curriculum is ready in September 2023. In that year, the first year of the curiculum will start. In the years after, the other years will be implemented.

In the third year, students are free to choose CBL learning trajectories in their free elective space.

There are also different multidisciplinary challenge based learning courses which will be developed.

These are courses which can also be followed here.

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Tech

HYDRA OF THE ATLANTIC:

THE EMERGENCY SHIPBUILDING PROGRAM

WRITTEN BY MARTIJN ZOER

The autumn of 1940 was a desperate period for the Allies. After the fall of the low countries, France and Norway, it seemed like Britain stood alone against the German onslaught. With the loss of France’s naval support, the battle of the Atlantic took a drastic turn. Germany’s U-boats and commerce raiders were inflicting heavy losses, and as a result Britain’s merchant ships were being sunk faster than she could replace them. For a time, it looked like they would be cut off from the rest of the world, and so a solution was desperately needed.

The Emergency Shipbuilding Program To keep the vital stream of equipment and resources flowing that the British so desperately needed, the United States would start to build cargo ships at an unprecedented scale. Originally a British trade mission secured 60 ships to be built by private shipyards. However, before construction could even begin, on January 3rd, President Roosevelt announced an increase in their current shipbuilding efforts and would produce a further 200 vessels. With that, the emergency shipbuilding program was born. This would be the first of five new waves that would be ordered throughout the war.

Design To build such a massive number of vessels, a special type of ship was needed. It would be based on the ocean class, the original 60 ships ordered by the British. The ocean class itself traces its design back to 1879. Changes were made to increase production speeds; most notably, riveting was largely replaced by welding.

Riveting is a lengthy and difficult process requiring experienced workers, which is not the case for welding. The new vessel would be designated ‘EC-2-S-C1’, where EC stood for Emergency Cargo, 2 for a ship between 121 and 137 meters, S for steam, and

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C1 meaning “design 1.” The ship was roughly 134 meters long, it had a beam of roughly 17 meters, and a raw tonnage of 10.000 tons. This was by all means not a small cargo ship for the time, the age of the design was very noticeable in factors such as the engine. In 1941, the preferred propulsion for steamships was a steam turbine. But these engines required specialized parts that were already in short supply, so it was decided to go with a compound steam engine instead. Liberty’s engines were designed to operate at 76 RPM which resulted in a speed of 11 knots, or 20 kph.

Teething problems

Tech

All was not without issue though. The liberty ships, especially the early ones, faced many issues. Although welding cut down production time because of its novelty in shipbuilding, there were still many kinks to be worked out. A result of this was a large number of hull fractures that could spread easily. Three ships suffered catastrophic failure and simply broke in half.

Another issue was the engine; although it was reliable its speed of 11 knots was deplorably slow. In particularly bad weather it would mean that Liberties could barely move at all.

SS Patrick Henry, September 1941

Liberty On the 27th of September, the earliest 14 of these emergency cargo ships were launched. The first of which was called SS Patrick Henry, named after the American politician famous for the quote “give me liberty or give me death”. The name liberty ship would stem from Roosevelt saying that they would bring liberty to Europe. Originally, they had a poor public image, stemming from the president referring to them as ‘a dreadful looking object’ and Time magazine dubbing them ugly ducklings.

SS Schenectady, broken in two before even leaving the shipyard, 1943

Victory The massive fleet of liberty ships would go on to complete their task. Although losses were heavy early in the war, the sheer number of ships crossing the Atlantic meant that the Germans were simply overwhelmed. Sink one liberty and 14 more will take its place, as 200 of the 2700 built were sunk. Combining this with more successful escorts and anti-U-boat technologies resulted in massive amounts of cargo reaching Britain’s shores.

Today there are only two still sailing, both serving as museum ships. The SS Jeremiah O’Brien docked in San Francisco and the John W. Brown in Baltimore. Both serve as museum ships reminding people of one of the greatest logistical feats ever undertaken.

Production Originally it took an estimated 230 days to complete one ship.

However, this time would change tremendously over the course of the war. The reason Liberty ships would eventually become known for insanely short production times was the introduction of assembly line logic to their construction. By 1943 it took only 43 days to complete one Liberty. Even more impressive is the record held by SS Robert E. Peary, which was launched after just 4 and a half days. Granted, plenty of finishing work still had to be done on it afterwards, it was still a testament (and publicity stunt) to the US’ industrial might at the time. At the height of production 3 of these ships would be launched daily. Throughout the war a total of 2.710 Liberties would be built.

The SS Jeremiah O’Brien, Passing through the tower bridge on it’s way to normandy for the 50th anniversary of operation overlord, 1994.

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Career

INTERVIEW SETTELS SAVENIJE

WRITTEN BY BEN GORTEMAKER

Settels Savenije is a group of companies located in Eindhoven next to the Philips de Jong Park. They are a versatile tech company that occupies itself with research, development and manufacturing of high tech solutions for its customers. For this article, we’ve got the opportunity to talk to Piet van Rens and Niels van Giessen who work for Settels Savenije.

About Settels Savenije

Firstly let’s talk a bit more about what kind of company Settels Savenije is, and what makes it unique. Starting with the location, it is in Strijp next to the Philips de Jong Park. Here you can easily take a walk in during a break, and it is quite close to the city centre. Next to that their office building is inside of the old water facility of Philips. What used to be large water containers are now offices creating a unique and inspiring work environment.

Next to the office building, they have fabrication and test facilities. These have everything needed for the high-precision engineering they do in-house. These buildings are very new but from the outside still fit in the style of the rest of the old buildings nearby. On top of that, they have been built in such a way that a lot of natural light comes in, making the space feel very open and making artificial light almost unnecessary.

Piet and Niels

Let’s introduce you to Piet van Rens and Niels van Giessen.

Beginning with Piet. he is an independent engineer that recently won the ASPE lifetime achievement award. He advises engineers, mostly at Settels Savenije but also at other high-tech companies. He previously worked for Philips for about twentyfour years and has taught de design principles of Wim van der Hoek for many years.

Wim van der Hoek Award

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The Wim van der Hoek award is a construction award for graduation projects of technical schools and universities in the Netherlands or Belgium.

Wim van der Hoek (1924-2019) is one of the founding fathers of the construction principles as we know them today. His work at Philips CFT and teacher at Hogeschool Eindhoven has created the high tech industry as we know it today.

Piet van Rens

Niels van Giessen

How Niels first got in touch with Settels Savenije was for his internship. This is also where he first met Piet as he was the one taking the internship interview. The project involved designing a dynamically balanced shake sorter. The design was adjustable in stroke and frequency while cancelling reaction forces and moments to the fixed world. This was achieved by keeping internal kinetic energy constant. He managed to create a solution for this problem but sadly it never got used, and to his greatest disappointment the prototype he made got thrown away whilst moving.

With this project his enthusiasm for design principles and fundamental design was laid. Later at another company, he did his bachelor’s graduation project for which he received the Wim van der Hoek Award. Afterwards, he graduated in the group of Nick Rossiele, now led by Paul Vrancken and Hans Vermeulen.

He graduated at Microsure where he developed A microsurgical robot with a hybrid kinematic setup, which was further worked out and improved by Nick Habraken who also won the Wim van der Hoek Award.

Career A normal day at Settels Savenije The first question we had is what a normal working day looks like for them. With a chuckle, Piet answered that he just comes by and asks difficult questions. As he only has an external advisory function and does not work fulltime here. But what he does is very important however as he said that

or verified in the process. These models should lead to providing design guidelines and implementation concepts for later design stages. And sometimes new design solutions evolve from these project learnings which could lead to patent applications for the clients.

As a consequence, a normal day can be filled with very diverse activities.

For Niels, It depends on the project and project phase.

Currently, he is working on a feasibility project, where concepts are developed and tested to achieve a certain engineering goal. This involves designing, building and conducting experiments to gain insight into the physical principles of the project. The insights should lead to the setup of theoretical models which should be falsified

Following up on this question we asked what kind of advice they have for future engineers that want to work in the field of Settels Savenije. The answer to this was that straight up from your study you can’t be ready for this kind of work. But most importantly you must take these setbacks and mistakes, which at some times can be very expensive, and turn them into something you learned from and move on. You are doing this work because you enjoy it and you can’t avoid these setbacks. And only by taking the positive parts out of your mistakes you will be able to learn the field of high-precision engineering.

“You must be able to explain what you are doing, otherwise you try to make unviable solutions” -Piet van Rens.

“You are working with vibrations of picometers and in such specific frequency ranges that you will never work with as a student. You will have to learn a lot and be ready for some significant setbacks in your work. Because almost everything you think, say or do will be incorrect at the beginning. And even if you do your utmost best you can still completely miss the mark. But if you are willing to make mistakes you will eventually end up finding a solution” -Niels

Achievements The next question we had was about what they were the proudest of. For Niels, this was the suspension of an optical object. It was a deviation from a standard module which could be copied over to other situations.

It required seemingly impossible specifications to create this suspension with the given alignment accuracy requirements. Nevertheless, a solution was found and he received compliments regarding the ingenuity of the solutions.

For Piet one of the things, he was most proud of is that a technology he worked on 40 years ago during the time he worked for Philips on cathode ray tubes got used in a design 4 years ago. He enjoys most getting to use the knowledge he has built up over the years from all of the things he has worked on and this is a great example of that.

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Career

Following up on this question we wondered how the construction principles have changed over the years. And for them, they have not changed, and as Piet said: “The underlying principles are not changing, similarly are the construction principles not changing”. However, what is changing is how the philosophy of construction principles is spreading around.

It started with Wim van der Hoek who in 1955 started collecting examples of good and bad constructions and published this in a book called Den Duivels Prenteboek.

He taught construction principles at the Technische hogeschool Eindhoven from 1962 until 1984, where he educated many of the great engineers we have today. And to a large part thanks to him we here in the Netherlands are leading in the mechatronic industry.

For example, during that time in America, these construction principles were not a matter of subject. And Piet recalls haven given advice on an instrument of the American company and that they were dumbfounded about the things he was saying. Furthermore, he recalls that on a satellite that went to space that of all the instruments only a Dutch instrument was still properly aligned due to proper constraints. And of course, this was because this was the only one which had the deformations in control using design principles.

What kind of engineering work is done here Lastly, we wondered what kind of work an engineer could do here at Settels Savenije. The answer to this was that their engineering work can be summed up by the following three activities: 1. Creating solutions 2. Feasibility studies 3. Reducing negative effects of a design How it goes is that a customer comes to Settels Savenije with a problem and asks if it can be solved. If it is relatively simple they will look into creating solutions, but if it is technologically more difficult they will l look into feasibility projects or reducing the negative effects of a problem. For them, this is a process they go through with the customer and together they try to figure out what the customer needs. Because at times the customer themselves don’t even know what they need.

Any problem can be solved if you throw enough money and time at it, and the question then becomes how willing the customer is to pay the price. Some larger partners are willing to fund larger long-term projects because the value of the solution can be so much that almost any amount of money can be put into it. With these larger companies, you then be working on a very small and specific part and trying to figure out if it is possible to create a solution for the given problem.

Concluding

We thank Piet and Niels for their time and John Settels for the tour he gave us of their company. We hope that you as the reader have gotten to know Settels Savenije more as a company and if you are interested you can visit their website: www.sttls.nl and see if they might have a job for you!

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Association

THE EIGENFREQUENCY OF...

THE BAR WRITTEN BY BEN GORTEMAKER

We as an Association own many things, some of them quite new and shiny, and a lot of them have a lot of history. For those who don’t already know this rich history, we will tell you a bit more about it. But most importantly, in this column we will answer the question of what the eigenfrequency is of these wonderful objects.

The last object we will take a look at this edition is the Bar. Most of the bar is pretty rigid but the overhead lighting since it has been moved from the old location to the new location in Traverse as has become a lot wobblier. This is because it is only mounted at three points with long rods, which if you know any construction

principles does not constrain movements in the flat plane. And one side of the overhead lighting is attached to the wall.

The most unconstrained part of the bar is the entrance to the back of the bar where the Commissioner of Extraordinary Activities usually stands, and this is where we will test the transverse and longitudinal eigenfrequencies of the overhead lighting of the Bar. This resulted in the following eigenfrequencies:

Longitudinal (Hz)

Transverse (Hz)

1.43

3.1

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Bachelor Final Project

Dual-Phase Steel failure mechanism

The strength ductility trade-off is one of the current challenges to further improve the mechanical properties of steels: an increase in strength is often accompanied by a decrease in ductility and vice versa. This is also the case for Dual-Phase (DP) steels, which are one of the most widely used advanced high-strength steels for automotive applications due to their excellent mechanical properties and convenient thermomechanical processing procedures.

To overcome this trade-off challenge and further improve the mechanical properties, DP steels failure mechanism must be understood.

WRITTEN BY JOS GASTMAN

Education

DP steels mesostructure typically consists of martensite islands embedded in a softer ferrite matrix (Figure 2). These martensite islands have complex microstructures and can have a variety of morphologies. One such morphology is lath martensite, which appears in most heat-treatable commercial steels and are prone to align parallel to each other in a grain. This micro-structure with many substructure boundaries, shown in Figure 1, can promote plastic deformation through substructure boundary sliding. This sliding is understood to originate from the presence of retained austenite (RA) films between the martensite laths.

These RA films act like a greasy plane on which the laths can slide. This mechanism relies on the low slip-resistance of the FCC RA films compared to the BCC martensite laths and the orientation relationship between RA and martensite, resulting in activation of plastic deformation along the martensite/ austenite (M/A) interface.

Figure 1: Low carbon martensite substructure [Morito et al., 2003] Furthermore, recent crystal plasticity simulations on different infinite M/F interface microstructures where a single variant is assumed within the martensite island [Liu et al., 2021], suggest that the martensite substructure boundary sliding induces high plastic deformation localization in the near-interface ferrite matrix and dominates the M/F interface damage initiation, which is critical for DP steel failure. However, in practice these martensite islands have finite dimensions and complicated hierarchical structures with multiple different variants, the interaction between them may affect the sliding activation and further M/F interface damage initiation in DP steels. To complement the conclusions obtained on M/F interface damage initiation, the influence of the martensite hierarchical structure was investigated in this study through systematic crystal plasticity simulations, using a multi-scale modeling method.

Figure 2: SEM micrograph of DP steel mesostructure with martensite island (M/A) embedded in ferrite matrix (F). [Liu et al., 2021a]

Figure 3: Two variants in a single martensite island with variable volume ratios and simple shear loading orientations of 0, 45 and 90 degrees depicted with blue, green and orange arrows respectively.

Modeling approach

The geometry used for the crystal plasticity simulations was made and meshed using GMSH. In this study the focus is on one DP steel mesostructure with a single martensite island in a ferrite matrix. The island is kept circular to avoid shape effects, can be rotated relative to the ferrite matrix and subdivided into multiple variants. For this thesis the focus is on two variants in a single martensite island, as shown in Figure 3. These variants need some more explanation. The transformation from austenite to martensite occurs following a fixed crystallographic orientation relationship (OR) which, due to crystal symmetry, can be satisfied by up to 24 orientational variants. In the model that used in this thesis the Kurdjumov-Sachs (KS) OR is applied between the BCC laths and FCC RA films. A single austenite grain generally consists of multiple crystallites with each their own OR and KS variant. Additionally, it is thought that an austenite grain is divided into packets e.g. a group of laths with the same habit plane, which is again subdivided into blocks e.g. a group of laths with the same orientation/variant. The variants investigated here are V1, V7, V13 and V19, chosen from different blocks, whose crystallographic orientation can be seen in Figure 4.

As mentioned in the introduction, a multi-scale modeling method is used, consisting of a simulation stage on the mesoscale and a precomputation stage on the microscale. This is necessary as the mesoscale alone cannot properly simulate the martensite substructure boundary sliding and cannot incorporate the relevant microscale phenomena. The multiscale model provides a damage indicator ⅅIZ in the M/F interface zone as a function of the deformation gradient tensor FM/A of the near-interface martensite island. The FM/A is used to evaluate the effective sliding YM/Ahp, with which the damage indicator is computed.

46

Education

figure 4 : Habit planes of KS variants 1,7,13 and 19 in blue, red, green and yellow respectively

Simulation and analysis Two types of simulations were run in this project. First, the loading angle is varied between 0 and 45 degrees. An angle study was performed which showed that due to the symmetry of the geometry, these angles were sufficient for this thesis. The loading type used is simple shear in the horizontal direction (SSHP). Secondly, the volume ratio of the grains in an island is varied. Three different volume ratios were looked at, namely 25:75, 50:50 and 75:25, defined with a horizontal line across the island as previously indicated in Figure 3. For both types of simulations, either the volume ratio or loading angle was varied, not both.

Influence of variant interaction

The simulations for variant interaction resulted in two different cases. One where there is a high mismatch in sliding e.g. Va shows sliding while Vb shows little to no sliding, and one where there was a low mismatch in sliding e.g. Va shows sliding and Vb shows sliding in a different direction. The conclusions from these cases are discussed below.

The first case is a high mismatch in sliding. Sliding is restrained if the included angle between the habit plane of the variant and

a) Single variant (V1 at 0 deg loading)

b) Multiple variants (V1-V7 at 0 deg loading)

Figure 5: Sliding and boundary damage initiation in single and multiple variant island with high sliding mismatch at 0 degree loading

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the shear direction is parallel and inversely when these are perpendicular, sliding is easier. For example from Figure 4 it can be seen that the included angle between variants 1 and 7 with the shear direction is very different and a high mismatch in sliding is present. In Figure 5b this case can be seen. In a single variant island (Figure 5a) relatively homogeneous sliding is observed, with slightly more sliding in the middle of the island, indicated by the gray center. Furthermore, moderate boundary damage initiation can be observed, indicated by the blue-purple border.

In a multi-variant island the intensity of these two observations is increased. Figure 5b shows an increase in sliding along the variant boundary, leading to an increase in boundary damage initiation where it was already present.

As can be seen in Figure 6, the mismatch in sliding and its effect is loading direction dependent on loading direction. Compared to Figure 5, the localized sliding along the variant boundary is decreased, but still present. Since the included angle between V1 and the shear direction is no longer favorable, the sliding and therefore damage initiation has decreased in intensity.

The second case is low mismatch in sliding. Here, both variants show sliding due to loading caused by the more favorable included angles between the variant habit planes and shear direction e.g. V1 and V13 in Figure 4. An example can be seen in Figure 7. Again in the single variant island moderate sliding and boundary damage initiation can be seen. With the addition of a second variant, which also shows moderate sliding, a local increase in sliding and damage initiation is observed (Figure 7b). However, instead of localized sliding along the variant boundary seen in Figure 5b, the sliding is now localized along the sliding direction of the additional variant (V13), while the opposite side shows a decrease in sliding and damage initiation.

Similar results are found with variant 19 with a different sliding orientation. A loading angle dependency is also found.

a) Single variant (V1 at 30 deg loading)

b) V1-V7 at 30 deg loading

Figure 6: Sliding and boundary damage initiation in single and multiple variant island with high sliding mismatch at 30 degree loading

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In Figure 9 a comparison between volume ratios with high mismatch sliding can be seen. The same observation can be made that a larger volume ratio dissipates the sliding and damage initiation, while a smaller volume ratio increases the intensity. Increased boundary damage can be seen in Figure 9 for the smaller volume at the variant and interface boundary.

From this volume ratio study, it can be concluded that smaller volume ratios lead to an increase in sliding, which often leads to an increase in interface damage initiation. Looking at optimal volume ratios in martensite islands, a 50:50 ratio is preferred.

This ratio leads to a relatively uniform interface boundary damage initiation, which is preferred over small volumes with high intensity damage initiation. a) Volume ratio 25:75 (V1-V13 at 45 deg) b) Volume ratio 25:75 (V1-V13 at 45 deg)

Figure 9: Sliding and boundary damage initiation for different variants volume ratios

Influence of variant volume ratio Additionally, simulations were run focusing on varying the volume ratios of the variants inside an island. In Figure 7b, localized sliding was observed across the variant boundary.

In Figure 8, a similar phenomenon is seen, but with a clear influence due to the volume ratio. With a large volume ratio for V13 in Figure 8a, the sliding and damage initiation seems dissipated among the volume, possibly since there is a larger area to slide across. On the other side, Figure 8b shows an increase in boundary damage initiation. In addition, the sliding originates from the intersection of the variant and island boundary. Similar results were found in V19.

a) Single variant (V1 at 15 deg loading)

b) Single variant (V1-V13 at 15 deg loading)

Figure 7: Sliding and boundary damage initiation in single and multiple variant islands with a low sliding mismatch.

Conclusion

From the simulations two cases were found, one where there is a high mismatch in sliding and one where there is a low mismatch in sliding, both showing different results. Both cases are compared to a single variant island, which shows almost homogeneous sliding and moderate boundary damage initiation. The high mismatch case shows an increase of sliding along the variant boundary and an increase in boundary damage initiation, where it was already present. In the low mismatch case, a similar result can be seen. However, the increase in sliding is now localized along the sliding direction of the second variant and an increase in boundary damage initiation is only found in this area. From the volume fraction simulations it is concluded that an increase in volume means the sliding is reduced, possibly due to a larger area resulting in more resistance. Additionally, the sliding seems to originate from the intersection of variant and interface boundary. To improve boundary damage initiation a 50:50 volume ratio is preferred as this leads to a relatively uniform distribution of damage initiation.

a) Volume ratio 25:75 (V1-V13)

b) Volume ratio 75:25 (V1-V13))

Figure 8: Sliding and boundary damage initiation for different variant volumes ratios

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Association

Staut: The life of Ching Shih

The Queen of pirates WRITTEN BY FYNN SCHMIDT

In this article, I will delve deep into the fascinating life of a genius strategist, opportunist, and ruthless queen of pirates Ching Shih. This is a woman who lived in an undeniably predominant men’s world, used her quick wits and gorgeous looks to carefully climb the ladder of power and become maybe the most influential pirate figure in history. Before we take a look at her story, it is important to map the events that gave way to the conditions in which a young prostitute could develop into the pirate warlord she came to be.

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Association The Goldilocks conditions for piracy The lady now known as Ching Shih was born somewhere around 1771. At that time, Qing China was a powerful state previously ruled by emperor Qianlong and now succeeded by emperor Jiaqing. The emperors were quite successful in acquiring wealth and annexing land, but failed to meet the rapid increase in population with proper modernization.

Farmers were left poor and unable to make a proper living, which drove the population to seek other profitable trades, not uncommonly outside the scope of the law. Qing China had many successful naval trade routes, making piracy an already tempting profession. For pirates, the poor coastal farmers and fishermen made easy recruits. On top of this, there were not enough civil servants to cope with the population growth spurt, so local government duties fell upon local leaders. Unfortunately for the empire, the allegiance of these leaders was not always to the Qing Dynasty, but rather to their own localities and families. This gave rise to local warlords and rebellious factions like the White Lotus. The Chinese government struggled to maintain internal law and was left weakened and depleted in resources.

Meanwhile in Vietnam around 1790, a rebellion was taking place: the ‘Tay Son rebellion’ succeed and emperor Quang Trung rose to power. The reason why this is relevant, is that the emperor had lost a large portion of his navy. To counter this he hired Chinese pirates as privateers. Amongst them Cheng I, a notorious and ambitious pirate who sought to unify the major Chinese pirate groups.

From prostitute to warlord

Around 1801 Cheng was around the age of twenty years. She had survived infant death and disease on the streets and found her way into a floating brothel in Canton where she worked as a prostitute. Not much is known about her origin,

but it is likely that she was the daughter of a poor fisherman or farmer. The brothel was doing good business, especially with notorious pirates. Due to Ching Shih’s wittiness and elegant looks, she was quite in demand and found herself in bed with influential pirate warlords. Being the entrepreneur that she was, she sold information acquired in pillow talk in an effort to rise out of poverty. In comes Cheng I, pirate warlord and currently working as a privateer in a fleet for the emperor of Vietnam. Apparently, he saw the dazzling Ching Shih on many occasions.

Here the stories deviate a bit, one story tells how Cheng was enamored with the prostitute and courted her to come aboard his ship. Another rumor is that the pirate wanted her for himself purely out of lust and kidnapped her. In any case, Shih was happy to oblige, but on one condition. She would share in Cheng I’s business endeavors in a 50/50 split. She would not be confined to the bedroom, awaiting her husband’s safe return from a raid. Rather she wanted to partake in the business and strategic decisions as equals. Uncommon for the time, the pirate agreed.

Not much later Cheng I obtained Cheng Pao in a raid, a fifteen-year-old fisherman’s son who piqued the interest of the naval warlord. He became his lover and captain of his very own junk. Bisexuality was not uncommon among pirates.

The lad was even adopted by Cheng I and his wife, mainly to ensure inheritance rights. You’d think Ching Shih would not stand for her husband’s infidelity, but accounts tell us that she was also involved in this now love triangle. Hereafter she and her husband had another two kids of their own.

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Association The largest pirate federation of the South Chinese sea

Cheng I and his fleet were still hired by the Vietnamese emperor when the Tay Son forces were defeated. During the time he was employed, he reinforced his fleet with the many poor and abandoned farmers and fishermen, who suffered as collateral damage in the dispute. Now that their employer was defeated, they returned home to the waters of southern China. They found that the Chinese government was too much preoccupied with subduing a rebellion of the White Lotus to properly fend off the pirates. So instead of demobilizing, Cheng I and Shih united the pirate fleets under six flags; white, green, yellow, black, blue, and finally their very own red flag. They tactfully set up relations with the chieftains of each fleet. The red fleet was a force to be reckoned with, the largest in the sea and now each of the fleets was run by a trusted subordinate, tied by familial and personal obligations to Cheng I. The pirate federation was formed in 1805 under Cheng I.

For two years the pirates terrorized the sea and coast before Cheng I died suddenly at sea. Most likely his life came to an end in a storm, but not much is known on the subject. His death threatened the stable relatively stable reign of the pirate group. Ching Shih was not about to let the group fall apart, she intensified the relations with all the chieftains and appointed her adopted son Cheng Pao as commander of the red fleet. Cheng Pao was recognized for his skill as a pirate and the others regarded him with respect. Moreover, he was very loyal to his adoptive parents who gave him his whole career, making him the perfect candidate to succeed his father. Ching Shih was the mastermind behind a large portion of the pirate groups business, which had made the company so much money in recent years. Undoubtedly this played a role in her being able to keep the pirates united. She married her son-in-law Cheng Pao and retained her rule over the pirate federation.

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The rule of Ching Shih The next couple of years truly showed how shrewd a tactician Ching Shih was. She set up a code of law for the pirates to follow, with heavy consequences when ignored.

1.

2.

3.

There was a clear chain of command, anyone who dared to either defy an order or to give orders outside of the chain of command would find themselves beheaded on the spot.

Acquired booty would have to be presented for group inspection, which was then registered by a purser. The original seizer would get 20% of the loot, the rest was placed into the fleet-wide public fund.

No one was allowed to steal from the public fund or any villagers that supported the pirates.

Any infringement of the rules would be met with either beheading or severe torture. Furthermore, deserters would have their ears cut off and paraded along their sneering crewmates. These rules

are said to make the pirate force relentless in an attack, desperate in defending, and unyielding even when outnumbered.

Furthermore, to keep the pirates in check, Ching Shih and Pao set up an easy but effective ploy. You may not think it, but the pirates were quite religious. Before each expedition, the commanders would seek divine approval from their gods. The Cheng’s built a temple from a ship and informed the priest of their plan prior to this. The priest would always approve, and the pirates followed.

Ching Shih also set up some rules to safeguard any women swept up in their operations. The pirates were prohibited from raping any captives and even consensual sex was forbidden. In the case of the latter it could be resolved if the pirate took the woman as his wife, infidelity was not tolerated. Beautiful women would be sold into slavery or as prostitutes while the ugly ones would be set free.

Association The terror of the Southern Chinese sea

Like any money-hungry warlord, Ching Shih sought to enter a more legal business. Between 1807 and 1810, she deployed two squadrons to intercept and seize merchant ships the government had sent out to haul salt. Instead of just appropriating the cargo, she forced the crew to continue hauling salt, but now taking a large commission. With their large force, the pirates terrorized the sea. Their reign took up all trade routes and they made merchants pay for their protection. Like with any crime organization, this was of course protection from the pirates themselves. And the merchants paid, they found it less risky and costly, than to buy their protection from the empire.

To give you an idea of the scope of their organization, Ching Shih had roughly 70.000 pirates working under her. Her personal squadron consisted of thirty-six vessels, manned by 1422 men who operated over 200 cannons. It is said that empiric forces stationed on the Chinese coast would sabotage their own ships to avoid confrontation with Shih. One of her favorite tactics was to rain down cannonballs on fortresses from afar. In the meantime, a small junk carrying vicious pirates would moor near the fortress and overrun it, while the enemy forces were still scattered and confused.

Portuguese and British merchants from the East-India company were also often attacked in Ching Shih and Cheng Pao’s ruthless conquest for wealth and power. The countries had offered China their help on multiple occasions since the pirates were a menace to them as well. But the emperor was not having it, the Chinese were simply too proud to ask for help outside of the borders of their empire.

That was, until 1809. In that year, the pirate federation expanded its business to include more than just the salt trade. It can be said that they had a monopoly of violence on the South Chinese sea.

They set up financial offices around the coast, where villagers could pay fees to exempt themselves from pirate raids. The federation even demanded levies and taxes be paid. This money was used to further reinforce their naval might.

Ching Shih had set up an intelligence network of farmers and fishermen who sold the pirates information about enticing bounties or enemy ships. She later found cooperation in bandit gangs and corrupt government officials. This conniving plan proved to be important in the conflict with the empire.

Their advance inland made them an even larger threat than they had already were and so a military commander in chief of Chekiang province was dispatched along with 135 ships to deal with the pirates. Naturally, he was killed and within six months 63 of his ships were annihilated. A year-long cannon fire blackened the skies. Now the emperor was more openminded in taking the British and Portuguese up on their offer to help. Cheng Pao wrote a letter to the Portuguese in an attempt to get them to change sides. After he would undoubtedly take down the empire, he would gift them a couple of provinces. The negotiation failed.

Negotiations Feeling that the tides were changing, Ching Shih promised the empire she would disband the federation if they could meet her demands. Her demands were of course laughable, but she felt that she still had the upper hand. Pai-Ling, general of LiangKuang refused her offer. The demands she set were as follows: 1.

2.

3.

The pirates would get amnesty for all of their past crimes.

They would get to keep their bounty, moreover, she would get to keep eighty vessels for her personal fleet, on top of which she would get forty junks to be used in salt trade.

Each pirate would get assigned government jobs.

What made the general ultimately refuse the offer was the number of junks the pirate queen would get to keep. They had a couple more encounters to negotiate the deal, but to no avail.

And so, Cheng Pao and Ching Shih continued to raid. Every coastal village would know their terror. But even their forces were depleted after the year-long siege on the richer parts around Canton. After taking a hit in a recent expedition and after narrowly escaping a blockade with some clever maneuvering, Ching Shih knew it was time to renegotiate the terms of her disbanding. It was either that or continuing to fight basically half the world.

She set sail with her fleet towards Canton, where she would meet Pai-Ling and important government officials to discuss the matter. But still, she proposed her laughable demands.

The officials were not about to cave to her determination, until she ordered her pirates to invade the surrounding areas. The queen of pirates was not messing around and the officials knew.

Ultimately they did cave and agreed to all of her terms. And so the matter was settled.

Cheng Pao became a rising government official and lived with his wife Chen Shih and the biological kids of Cheng 1. Ching Shih was still operating in the salt business. When Cheng Pao died in 1822 at sea, Ching Shih opened a gambling house that doubled as a brothel. She amassed a fortune and later even acted as a military advisor in the first opium war in 1839. She died peacefully around 1844, surrounded by her family and immeasurable mounds of treasure. If there is one thing we can take away from her fascinatingly crazy life, it is that even when dealt a shit hand, opportunities will present themselves. The hard part is to properly take advantage of them.

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Education

INTERNSHIP AT NTNU WRITTEN BY GLENN LANGERMANS

At the end of April, I headed for higher latitudes in Norway leaving behind my regular dayto-day to do an internship at the NTNU in Trondheim. Getting there proved to be easier than expected, a short direct flight from Amsterdam, about 2,5 hours and an hour-long bus ride (after finding the bus stop, which was not easy) brought me to my home for the next 3 months. Trondheim being quite a bit farther north than the Netherlands brought with it some interesting challenges from snow in the first days of May, to it not being dark for long in the night. Around the longest day it is fully light for more than 20 hours, the rest of the time is filled with twilight, which really messed with my sleep, waking up at 4 thinking that it is 10 is not great.

After 2 days in Norway, my work started at university. During the next 11 weeks I would spend almost all weekdays at university, usually starting at 8 o’clock and working until half past 4, most students in Norway also started quite early. Fun fact going to university by bike took me about 5 minutes, but traveling back took more than 15 minutes, this might seem like a big difference but if you factor in that most of the way to university was downhill, and back was uphill (covering about 70m in

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height with quite some steep sections) it is not that strange. I did my research in the Structural Engineering department in the SIMlab group, as their name might give away, they specialize in both simulation work and impact testing, unfortunately my work did not involve impact testing, instead I worked on SLA printing, which is a form of 3D printing in which light is used to locally cure a resin to form structures.

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My assignment

My assignment was to verify a possible reason for discrepancies between results in compression of 3D printed structures and the simulated results gained using a material model based on tensile experiments. The postulated reason was that a difference in post-curing could explain the difference between tests and simulations.

To test this hypothesis a two-pronged approach was taken. Firstly, a new structure was tested and simulated in compression whilst making certain that the post-curing settings were kept constant, and secondly, the post-curing times were varied to see if a difference in curing time would explain the discrepancies. After quite a bit of testing and simulating the results were the following, both yield stress and young’s modulus of the material depend on the cure-

time, while no such relation could be found for stress and strain at break, finding that these variables are most likely initial fault driven.

These post-curing time results however do not explain the discrepancy between experiments and simulations fully, so further research was needed to find why they did not match.

Free time in Trondheim

Most of my free time, at least when the weather was managable, was spent out and about enjoying the nature that Trondheim has to offer. From hiking trails in Bymarka and around Estenstadmarka to climbing the beautiful cliffs of Hell, Støren and Korsvika or simply going for a bike or walk around town.

What I noticed during all these trips is the love that most Norwegians have for the outdoors, if you go anywhere when the weather is good you are bound to run into people enjoying activities outside. If you are ever lost or unsure where to go, you can ask any local and most likely they will answer you in perfect English and be very willing to help.

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Education

After I returned from my trip to Norway, a lot of people had many questions but 2 kept popping up and these I will answer.

Firstly, do you want to go back to Norway, which I can only answer with a fullhearted yes. There is still much more to see in this country and a lot more I would like to explore and do. The second is, what have you learned from your trip, putting aside all that I learned from my assignment (which was a lot) the thing I keep going

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back to is take every opportunity, if the weather is nice, to go outside because it might take days or even weeks till that happens again. If any of you are doubting if you should do an internship abroad, I fully recommend it. Meeting new people, exchanging ideas and emerging yourself in another culture not only broadens your horizon but also gives you more insight into who you are.

ENGINEERING REALITY

WRITTEN BY RYAN LEAL

“I DON’T WANT THE PUBLIC TO SEE THE WORLD THEY LIVE IN WHILE THEY’RE IN THE PARK. I WANT THEM TO FEEL THEY’RE IN ANOTHER WORLD” ~WALT DISNEY

Technology is advancing faster than ever. Especially in theme parks like DisneyLand, where as demand for more realistic design increases, rides with slow-moving carts, a few flashing lights, and a few decorations and simple animatronics are becoming a thing of the past.

Tech

Nowadays it takes more to engross children, teens, and their families. Like movies and video games, theme parks must also adapt, using better props , cinematography, and audio to help transport people into the world of the ride. Except to do this requires many disciplines: structural or mechanical engineers, electrical engineers, computer scientists, architects, artists, special effects designers, lighting designers, and more all working together to produce aesthetically pleasing and exciting theme park rides. Do you have what it takes?

Ideation to Materialization At Disney, it starts with their theme park engineers, dubbed ‘Imagineers’, that brainstorm idea for new rides and attractions, and design interactive systems from their ideas to bring them to life. But this cannot just happen immediately.

Often a mock-up is created beforehand to see how system pieces fit and interact together. Disney does this through the WorldBuildr platform, a software where it’s timeline-based UI simplifies the combination of immersive and dynamic elements to model real-life rides. This can simulate a cart’s movements through tunnels while showing the walls, set pieces around, flashing lights, and pyrotechnics, giving all aspects of the ride a place to interact. Once these mock-ups are in their final stages, they are put to the test being reviewed by theme park guests, whose opinion helps further designing from a fun experience perspective.

The Star-Wars: Rise of the Resistance attraction

One of the most exciting rides recently designed is ‘Star Wars: Rise of the Resistance’ at Disney World in Florida. It is a massive attraction which begins with you (as a Resistance recruit) in a transport ship that is being tailed by First Order guards. In this complex machinery, you are in a room that moves! Not predictably, but it moves as the transport ship pilot dodges enemy fire. The window screens alongside you are showing the First Order blaster beams that pass along side you and the room correspondingly moving left or right to avoid the heavy fire. It is just one of the many ways theme park

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engineering has stepped up, using the technology available to create an immersive experience combining many disciplines of art and engineering. Once captured, you are taken into the First Order’s Star Destroyer, thinking all is lost but luckily a covert team of the Resistance (actors) arrives, on a mission to bring you home! Now on a complex trolly that moves in and out and twists left or right using elaborate self-driving technology, you travel across this Star Destroyer while looking for an escape pod to safety. Doors using sensors open or close for a duration, so you are able to view the battle between real First Order guards and the Resistance. Blaster bolts appear around the sides of the walls and pyrotechnic sparks become the aftermath of the damage done by these blasters. One of the most exciting parts of the ride is coming face-to-face with the evil First Order leader Kylo-Ren himself. He is an animatronic —fortunately, but his arms are moving up and about as your trolley rolls toward him is a very impressive attempt at engineering the world of Star Wars; simulating one of the coolest abilities: the Force-pull. This is all achieved using a perfect combination between timed animatronic technology and preprogrammedrolley movements. Finally, amidst all the panic, an escape pod is found, and the room drops you (literally drops you a short distance) down and out of the danger. The whole space flight to the Resistance base, of course, is simulated using the window screens and this room’s movements.

All in all, the future of rides, using cutting-edge engineering by combining current technology and special effect set design, is a realm unlike any other and will be interesting to pursue not just for mechanical engineering, but from many disciplines. With the tremendous advances in technology and art, it is exciting to see what next is in store for theme parks in achieving Walt Disney’s dream: putting you into another world.

Education

MEET THE NEW MANAGER OF...

ESA-ME WRITTEN BY YVES HOUBEN

Hi all! As of September 1st, I started as manager ESA for the department of Mechanical Engineering, which includes the role as chain manager teacher support for parts of ESA, General Affairs, HRM and all teacher supporters of the departments.

After my previous position as interim manager ESA of the department Mathematics and Computer Science I am looking forward to bring my experiences to Mechanical Engineering, but also to learn about all the wonderful things and people in my new team and within the department. A departmental ESA team is a very diverse group of people who are very capable of their own craft. These crafts include, amongst others, academic advising en educational sciences. Both very large fields with a lot of international research which can be brought in to practice. With as goal to support program directors, teachers and students as much as possible in their own roles in education.

The role of manager ESA has some complexity as you have a team to lead and support, represent the department on central ESA level and at the education board, and represent ESA central policy topics in the department. Nevertheless, I encourage everyone to reach out to me if they feel it is needed. High on my priority list are always social safety, diversity and inclusion.

In my opinion Simon Stevin has an important role in community building and helping us to achieve the joined goals we have for our education programs and the student affairs around these. I will join the board in discussions and actions to strengthen the role and position of Simon Stevin. And also remember others in the department pro-actively about the role a study association can play in our educational policy making, educational developments and social interactions.

The upcoming years are challenging times for all of us. A lot of us will move around, or even outside, of the campus. The social cohesion and interpersonal connection at the department will be at risk.

We all will deal with uncertainties in new educational developments, the scale jump, the bachelor college redesign, and later some possible changes in the academic calendar and the graduate school redesign. My advice is to keep looking forward; share concerns, needs and wishes and in the end there will always be duct tape, WD40 and social drinks.

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Association

GRIND MY GEARS

WRITTEN BY BEN GORTEMAKER

With grind my gears the Editorial committee visits the bars of other study associations and asks them mechanical engineering questions. For this edition, we went past Protagoras, Thor, J.D. van der Waals and GEWIS. Lastly, we also asked some mechanical engineering freshmen to see if they are ready for their study. The questions we asked them were as follows: 1. What is higher: dynamic or static friction?

2. What does RVS stand for?

3. Where is the pressure the highest?

6. The entropy of an adiabatic closed system: a. can both increase and decrease b. can only increase c. can only decrease d. is always conserved e. none of the above 7. A ping-pong ball can be floated in an upward air stream. It is stable against fluctuations from left to right, so it doesn’t fall out either side. Explain this stability?

4. how many zero force members are there?

8. How many degrees of freedom does the following structure have?

5. Which Bode plots depicts a PD-controller?

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Association

1. What is higher: dynamic or static friction?

We started this quiz off easy with the simple question of what is higher, dynamic or static friction? For those who have not followed physics closely: friction is the counteracting force that occurs between two objects in contact, and it is proportional to the normal force which is the force that is pushing the two objects together, usually this is gravity. Static friction is the friction that occurs when the object is not moving, this force must be overcome and then the object starts moving. When the object is moving it encounters dynamic friction, this friction is lower than static friction.

You encounter this phenomenon in your everyday life when for example you try to push a heavy box. It is always hard to move at first, but once it is sliding it becomes easier. This is also the reason why twisting something loose that is stuck is easier than straight-up pulling it out.

For most people, this question was quite easy, however our neighbours at Protagoras got this question wrong. But more worrying is the fact that when we asked our freshmen, they also got this answer wrong, I suggest that they follow the lectures on dynamics well because it seems that they will need it.

2. What does RVS stand for?

RVS is the Dutch abbreviation for stainless steel, and is more commonly used than the complete word “Roest Vast Staal”. Taking this literally it means rust-resistant steel, but the abbreviation often gets confused with “Roest Vrij Staal” which translates to rust-free steel. The two things are completely different, so it is important that as an engineer you know the correct meaning of RVS. Because if you order rust-free steel you will get something completely different from rust-resistant steel. On top of that, it is also in our Association Song, so as a member of Simon Stevin you definitely need to know the difference. That is why we wanted to ask this question and see who knows the correct meaning of RVS. And it is sad to see that here at the Technical University of Eindhoven not a lot of people know the correct meaning of RVS. Only GEWIS, one person at Thor and one person at Protagoras got the question correct.

Even our freshmen got the answer incorrect, showing once again that they have quite something to learn.

3. Where is the pressure the highest?

In this question, we have varying shapes of containers with the same liquid at the same height. The surface area at the bottom is equal in all cases and the second container contains the most fluid and the third the least. However, these variables are not relevant to the question, because the only thing that is relevant to the pressure at the bottom of the container is the height of the fluid itself. Meaning that the answer to the question is that the pressure is equal in all cases.

It is a bit of a trick question and most of the other Associations did not get the correct answer, most of them thought that the second container had the highest pressure at the bottom. The only ones where someone got it correct were J.D. van der Waals and Thor.

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Association 4. How many zero force members?

In a truss structure members are modelled as one-dimensional rods, meaning that they only can transfer a force in their axial direction and for the rest of the degrees no forces can be transferred. Zero force members occur when in a given node there is no counteracting force in one given direction. With a node with 2 members attached and no external forces, they occur if the members are not parallel to each other. In a node with 3 members and no external forces, they occur when 2 members are parallel to each other and the third is not, the member that is not parallel has no force on it.

The answer in this case is 5 and the nodes are marked in the image. Only one member of Thor got this correct and one of the members of GEWIS got it correct by rolling a die. On top of that, our freshmen got this question correct.

It is fair to say that it is better to leave the truss structure design to mechanical engineers.

5. Which bode plots depicts a PD controller?

A bode plot depicts the magnitude and phase of the response versus the frequency of the input. A PD controller is a controller with a proportional and a derivative controller combined. The proportional controller is independent of the frequency and increases the magnitude of the output proportionally, and thus results in a flat line as seen in answer b. A derivative controller increases the output magnitude proportionally with the frequency and increases the phase by ninety degrees. Then a PD-controller does both of these things resulting in the controller as can be seen in answer d.

Somehow some of the members of Thor got this answer incorrect, and with some miracle of luck, Protagoras got this answer correct. The rest of the associations got this question incorrect. On top of that, our freshmen did not know what a controller entailed and got this question wrong.

6 . The entropy of an adiabatic closed system There are various ways of modelling the thermodynamic behaviour of systems, and important for them is which boundary conditions you set. An adiabatic closed system is one example of such a system. And entropy is the measure of chaos in a given system, it is related to the amount of energy the system contains.

An adiabatic closed system is a system where no heat and mass transfer to the outside world occurs. Meaning that the number of particles and the energy of these particles stay the same. This results in the fact that the total amount of energy in the system is constant and thus the amount of entropy is always constant.

Almost everybody got this question correct, even our freshmen, however, Thor was the only one who got this question wrong.

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The entropy of an adiabatic closed system: a. can both increase and decrease b. can only increase c. can only decrease d. is always conserved e. none of the abov

Association

7. Stability of a ping pong ball The reason for this stability has to do with the velocity of the flow. The middle of the air stream goes faster than the outside because the outside parts encounter viscous friction with the outside air. This results in a faster air stream in the middle, and when air moves faster the pressure is lower. Meaning that there is a low-pressure area in the middle of the air stream. The ping-pong ball is sucked into this lowpressure area and stays there because the outside has a higher pressure and is pushing the ball inside.

This was one of the trickiest questions and there were a lot of theories for why the ball would stay in the middle, some of the associations getting quite close and others not even making a chance. The answer to the question is not very intuitive to most and that is why most people found it very difficult. But in the end, only one association got it correct and that was J.D. van der Waals.

8. Degrees of freedom Degrees of freedom are the directions a given object can freely move in. For this problem there is quite a simple thumb rule: and that is the fact that every rod (if placed correctly) can constrain 1 degree of freedom. This construction has 5 rods meaning that there is only 1 degree of freedom left over, and this is a translation in the x direction.

However, this thumb rule does not apply when one rod is fixating the same degree of freedom, in that case, you get a statically undetermined system. A statically undetermined system can move in unpredictable ways when under any kind of load. This is very undesirable when you try to make an accurate and predictable mechanism.

In this last question, almost nobody got correct, and only one person of Thor was able to get it right. It seems to be that not a lot of people even know what degrees of freedom are.

Concluding First of all, I want to thank everybody for participating in the quiz, and as a committee had a lot of fun going around all the bars of the university. The scoring has been done by taking the number of correct answers given by various people in the association and taking the average of it.

From the scoring, we can see that we have a tie between Thor and J.D. van der Waals which both have a 5.4 as their grade. It is almost a pass in terms of a grade but that does not matter for today. And a rematch would be needed to conclude which study makes a better mechanical engineer. After this with only a 0.6-point difference comes Protagoras, and after this comes GEWIS. Last come our freshmen with a terrible score of 3.5. However, one factor that might have influenced the scoring is how far we were into the drink because at GEWIS and Simon Stevin the drink was already going for quite some time.

Lastly, I want to congratulate the winners of this edition of grind my gears.

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Tech

THE CITY OF ANGKOR WAT WRITTEN BY MARTIJN ZOER

Roughly five kilometres north of Siem Reap in Cambodia lies Angkor Wat, a massive stone temple that has been the largest religious structure for the past 900 years. It sat at the centre of one of the largest pre-industrial cities which itself served as the royal centre to one of the most sophisticated kingdoms in the history of Southeast Asia.

The Khmer

The story of Angkor Wat starts with the Khmer. In the year 802 a man named Jayavarman II declared himself king over the region that is now Cambodia. Jayavarman II was responsible for unifying the fractured kingdoms that preceded him and declaring independence from Java. He would go on to found the city of Angkor just north of Tonlé Sap. In the 12th century, Suryavarman II would become king after defeating his rival in battle. He would go on to start construction on Angkor Wat, likely planned as his tomb, which would take roughly 30 years. The structure would not be finished before his death during one of his campaigns into Champa, located in what is now Vietnam.

The temple of Ta Prohm. it served as a monastery and university.

The empire would enter a state of decline in the 13th and 14th centuries. It is largely accepted that the year 1431 marked the end of the Angkorian period. After the city was sacked by the kingdom of Ayutthaya (modern day Thailand) the capital was moved to Phnom Penh.

Jayavarman VII

Suryavarman II

Following his death, the Khmer would once again plunge into a period of chaos, ending with an invasion and sacking of Angkor by the Cham. Jayavarman VII would take power in 1181 and would set to work on a new capital just north of Angkor Wat, the walled city of Angkor Thom. He would go on to build temples such as Ta Prohm, and Preah Khan honouring his parents. More famously, he was responsible for the construction of more than a hundred hospitals and many more infrastructure projects. For his contributions he is often seen as one of the best kings in Khmer history.

The south gate and entrance to the walled city of Angkor Thom.

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Angkor

Throughout the history of the Khmer, the plains of Angkor would house multiple of its capitals. All of these combined into a sprawling low-density metropolis. At the city’s peak more than three-quarters of a million people were housed in the 13th century, meaning it was one of the, if not the biggest preindustrial cities on earth. At the center of this city stood some of the most impressive works of architecture in our history including the biggest religious structure of all time: Angkor Wat.

Angkor Wat

Angkor Wat covers 160 hectares which is more than three times the area of Vatican City. A 190-meter-wide moat surrounds the temple grounds resulting in only two points of entry, an earth bank in the east, or rear, and a stone causeway in the west which features as the main entrance. The complex was dedicated to the Hindu gods Shiva, Brahma and Vishnu. The temple’s five central towers represent the peaks of Mount Meru, the abode of the Hindu gods. Standing at the west entrance the sun can be seen rising directly from the central tower. The structure is covered in carvings depicting scenes from the Khmer’s history as well as Hindu mythology, although many of the latter carvings would be replaced by Buddhist art following Jayavarman VII’s conversion to Buddhism.

Tech

Angkor Wat seen from the front during the spring equinox Waterworks

One of the reasons for Angkor’s immense size is due to the Khmer’s mastery of water. The metropolis is often described as a ‘hydraulic city’ for this reason. A vast network of canals fed the city. The size of this network only became clear after a massive survey of the land using LiDAR and ground-penetrating radar.

From these reservoirs numerous canals originated, serving as a form of transport as well as a stable water supply to the citizens of Angkor throughout the year. Although this system is what allowed Angkor to flourish, they ironically contributed heavily to its downfall.

The reason for the existence of Angkor’s massive water network was to create a year-long supply of water to the population.

Angkor was located in the lower Mekong basin which meant it was subject to yearly monsoons, a wet season in the summer and a dry season in the winter. To store enough water for the city to survive the dry season massive reservoirs, or barays were built.

The largest of which, the 53 cubic meters West Baray, still holds water today.

A map showing the many surface features of the Angkor region such as the canals.

Decline

Satellite imagry of the Angkor region, the massive West Barray is clearly vissible, as well as the moats belongin to Agkor Wat and Angkor Thom.

There are many factors that led to the decline of Angkor. The previously mentioned kingdom of Ayutthaya played a big role.

But recent research shows that a changing climate helped seal the city’s fate. In the 14th and 15th centuries the weather became more extreme, longer monsoon seasons were followed by more intense draughts. To cope with the draughts, many changes were made to the system to keep the water level high enough. however once the more severe monsoons returned these changes resulted in floods and major damage. Following the move of the capitol to Phnom Penh most of Angkor would become abandoned. Many of the temples were swallowed by the jungle such as the famous Ta Prohm. Though Angkor Wat would always remain a place of worship.

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Association

DCME, WHO ARE WE? WRITTEN BY SANDER VISSER

Hi, my name is Sander Visser. I am a 5th year mechanical engineering student, currently finishing my bachelors.

During my bachelors, I have done many things aside of my studies. I have been active at Simon Stevin in different committees, am part of Rhetoricadispuut Tau and have done a fulltime board year at student team InMotion. On top of this, I have been active in an organization of which you might have heard, but know not so much about. Namely the Department Council of Mechanical Engineering (DMCE) or “Faculteitsraad”. In this article, I am going to explain to you what the DCME does and how it can help you, so you know who to go to in the future!

The DCME exists of both students and personnel of the faculty. Every month, five students and five staff members meet each other to discuss several topics regarding our faculty. The students that get to be in the DCME are elected every year by the students of their faculty.

The staff members have the same type of elections for their representatives, so everyone gets to have a say. A representative of the board of our faculty is also always present in the monthly meetings, so we can ask questions or raise points directly to the board if deemed necessary.

A grasp of the things that are addressed during the meetings of the DCME are the PER/ OER, containing information on the content of our study program and assessment within the program and the yearly budget of our faculty. On top of this, topics that are addressed by students, staff or other people are discussed during the meetings, to make sure they are heard by the board. Two examples of such topics are; the issues with two drinks at Simon Stevin, which could take place after notification of the DCME to the board that actions were already taken and cancelation was not deemed necessary, and the potential upcoming changes to the international office after multiple complaints from students regarding internships. Finally, one of the current big topics of discussion during our meetings is the renovation of the Gemini building, to make sure we are up to speed about any updates.

I, as part of the DCME, hope to have given you some insight into what we do. We want you to always feel free to contact us in case of any type of complaint or compliment. We can forward it to the board and make sure they will hear it!

You can contact me at a.e.visser@student.tue.nl.

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Association

SLITHERLINK This puzzle consists of a grid of points where each space between four points forms a cell.

The number in the cell indicates how many sides of the cell is hit by the line. The object is to create a single room of this one connected line. In addition, it is not allowed to have the line cross itself.

PUZZLES MADE BY RIK TIEBEN

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Association

STAR BATTLE Do you dare to compete! In this puzzle you will challenge your brain and see if you can win this defiant battle. To accomplish your goal you will have to draw stars in the squares.

However, there are some rules you have to follow. You may only put one star in each column, each row and most importantly only one star in each section that is bordered with a thicker line. Good luck and see if you can solve this puzzle.

PUZZLES MADE BY RIK TIEBEN

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Association

SUDOKU The goal of this Sudoku variant is to fill the grid, so that each row, each column and each region of 4x4 cells contain all the numbers from 1 to 9 and the letters from A to G.

PUZZLES MADE BY RIK TIEBEN

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Association

STERRENHOEKJES • Stefan onder naar het feestje van Eline: “ooh zij is extra ordinair lid toch?”

• Jasper: “Als ik signals nog haal pin ik een fust” • Pieter over laseelectroden: “Waarom hebben we zoveel sterretjes?”

• Lubbers: “Ik zag door de bakken en bos niet meer” • Rob van der Heijden tijdens vrijdag intro: “Ben ziet er bijzonder slecht uit” • Sander: “Wat is de FIOD?” Lianne: “Een soort OFAC, maar dan met geweren.”

• Nicky: “Cas je hebt me echt geïnspireeerd, ik heb gister ook laf geborreld!”

• Koen tijdens de case night: “Wel leuk om te zien dat zelfs ASML vindt dat Florian niet kan tappen” • Rik van de Vijfeijke: “Dat kan je toch niet doen?!” Bregje: “Ja inderdaad, je kan echt niet in een afgebrand huis slapen!” Rik: “nee ik bedoel dat je Florian achter de tap zet”

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Association

CONTEST TIME Submit your answer and win a 50 euro hardware store giftcard!

Contest 54.1 The Editor-in-Chief tells the three super-smart committee members Imke, Ryan, and Martijn: “Each of you has received an openME that carries a number from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Your three numbers are pairwise distinct, and the largest one equals the sum of the two smaller ones.

Now, please have a look at your cards with your number, but don’t show it to the two others!”

Imke, Ryan and Martijn stare at their cards for some time.

1.

After some time Imke says, “According to my knowledge, there are at most eight possible candidates for Ryan’s number.”

2.

Then, Ryan says, “According to my current knowledge, there are exactly three possible candidates for Martijn’s number.”

3.

Martijn shouts, “I see! Now, I know Imke’s number.”

4.

Imke thinks about it and says, “I still don’t know Ryan’s number.”

5.

Ryan exclaims, “I see! Now, I also do know Imke’s number.

Of course, we would like to know: What is Imke’s number?

Submit your answer in De Weeghconst (Traverse 0.34) or via an e-mail to redactie@simonstevin. tue.nl with your name and the solution. The prize will be raffled from the correct submissions and the correct answer will be published in the next winning contest.

Make sure to submit your answer before the 1st of March! The winner will be notified and announced in openME 54.2.

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December 2022 - “Scaling up”