openME 55.1

December 2023

“Reflective”

GEMINI-N OUR FUTURE HOME

SNEK: A TASTY REVIEW

WATCHES:

PRECISION TIMEKEEPERS

PREFACE Dear reader, Quarter one has just passed, and we are approaching the end of the calendar year. A perfect moment to reflect! What is going well, and what could be improved?

Reflecting is not new to us as aspiring mechanical engineers. We reflect during CBL projects, during the aftermath of an exam or at the end of the year to see if we are still in the right spot. In the world of reflecting, various emotions are involved. From the gratification of success to the discomfort of acknowledging shortcomings. It is in this web of thoughts that the seeds of improvement are planted!

Together with the editorial committee, I am delighted to present the first edition of this academic year. In this edition, we will reflect on the various aspects of student life, our beautiful Association and mechanical engineering this past year. A year with a more diverse group of freshmen than ever before, the start of the reconstruction of our new home in Gemini and the 55th volume of the openME! d read Test your mechanical engineering roots, find out which snack is enjoyed the most and about the evolution of student transport.

Enjoy reading!

With kind regards,

COLOFON

Stefan Geerts Editor-in-Chief

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December 2023, volume 55, issue 1 The ‘openME’ is a publication by the study Association for Mechanical Engineering Simon Stevin of the Eindhoven University of Technology

Editorial committee Aryan Bakermans, Jasper Bekkers. Ruben Bravo Veldhuijzen, Stefan Geerts, Imke Goofers, Ben Gortemaker, Daniël Kleinjan, Tom Slangen

Editor-in-Chief Stefan Geerts

Illustrations and Pictures Editorial committee, Cas Dijkstra, Photo committee, source stated otherwise

Design Maartje Borst, Rik Lubbers, Roelof Mestriner, Joel Peeters, Lex Verberne Layout Aryan Bakermans, Jasper Bekkers. Stefan Geerts, Imke Goofers, Ben Gortemaker, Daniël Kleinjan, Tom Slangen

Printing office Drukkerij Snep Circulation 800 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 GEMINI-N OUR FUTURE HOME

BEP: BUBBLE CUTTING EFFICIENCY

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13

FEATURED

TECH

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8

Engineering airplanes: Mechanics

5

BFP: Bubble cutting efficiency

15

TU/ecomotive

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Gemini-N | our future home

17

The eigenfrequency of a keg

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BFP: System identification for cooperative adaptive cruise control

34

Winter Blues

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Campus art

GEMINI-N | OUR FUTURE HOME

With the start of the rebuilding phase of Gemini earlier this year, the final building slowly taking shape. Learn more about the current progress in this update!

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SNEK: A TASTY REVIEW

Welcome to the world of SNEK! Embark on a culinary journey to unravel the mysteries of our beloved SNEK, revealing the best and brightest amongst our delectable offerings.

WATCHES: PRECISION TIMEKEEPERS It has existed for a considerable duration, helping us keep track of time the fashionable way instead of using our mobile phone; it’s the watch.

EDUCATION

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Mapping the stars: Euclid telescope

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Rental bike review

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Watches: Precision timekeepers

RENTAL BIKE REVIEW

WATCHES: PRECISION TIMEKEEPERS

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45

CAREER

ASSOCIATION

SPONSORED BY

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Interview: Settels Savenije

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SNEK: A Tasty Review

TU/e Mechanical Engineering

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Cooling of Thales’ Radar Systems

BAColumn: The Rum Renaissance!

OCI

27

Federation of Study Associations Eindhoven

Settels Savenije

31

Sταυt: What happened to mopeds?

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Cultural differences in ME

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Hephtig: Student protests

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Test your ME-level

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History of the CoBo

55

Puzzels

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Sterrenhoekjes

Thales ExxonMobil

BȲȰǥȨǡǞǛ FǤǟȲǡ PǛǞǣȨȰǙ A numerical analysis of the effect of different mesh geometries on bubble cutting efficiency During Q3 and Q4 of last academic year, I worked on my Bachelor’s Final Project within the Multiphase & Reactive Flows Research Group under the supervision of Rahul Sabburaj (PhD) and Niels Deen (prof.). I was tasked with investigating the effect of changing the geometry of a bubble cutting mesh.

WRITTEN BY T

H

Education Introduction

In recent years, the utilization of bubble cutting technology has emerged as a crucial aspect in various industrial applications, ranging from wastewater treatment to biomedical research. The efficiency of bubble cutting processes significantly depends on the intricate interaction between bubbles and the surrounding medium. One of the key factors influencing this interaction is the mesh geometry employed in the bubble cutting apparatus.

This bachelor final project aims to delve into the numerical analysis of different mesh geometries and their profound impact on bubble cutting efficiency. The term “bubble cutting” refers to the process wherein bubbles, typically entrapped gases in a liquid medium, are selectively severed or fragmented.

The efficiency of this process is pivotal in applications where precise control over bubble size, distribution, or elimination is paramount.

Understanding the influence of mesh geometries on bubble cutting efficiency holds immense practical implications. For instance, in the field of wastewater treatment, where the removal of gas bubbles from liquid effluents is vital, optimizing the mesh design can enhance the overall treatment efficiency.

Moreover, in industries requiring precise control over the size and distribution of bubbles, such as in the production of foams or emulsions, an in-depth analysis of mesh geometries becomes indispensable.

General concept

Gas-liquid-solid flows are frequently used in trickle bed-, and bubble slurry reactors. Within these reactors, the solid phase material often functions as a catalyst, whereas the liquid and gas react with one another. As the gas bubbles propel upwards in the liquid, they coalesce to form larger bubbles, as these have relatively low surface-to-volume ratios decreasing the relative surface tension per unit volume. This decreases the reactivity of the two phases, as less bubble volume comes in direct contact with the surrounding liquid, resulting in a lower reactor efficiency.

To combat this, a mesh of wires that run horizontally through the column can cut the large bubbles, also referred to as ’mother’ bubbles, into smaller ’daughter’ bubbles. This method has been proven to be effective at increasing the overall surface area between the gas and the liquid, which greatly improves the reaction efficiency.

Another study has shown that the passage or cutting of a bubble is dependent on the Eötvös number Eo. This number characterizes the bubble’s deformation properties with its diameter and describes the bubble properties such as density and surface tension coefficients. Bubbles with Eo > 4 deform and pass through the wire mesh, whereas bubbles with Eo > 15 are cut by the wire mesh, if they hit the mesh at a wire crossing. In this study, a square wire mesh was used to perform the analysis.

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Education Eötvös number g

The bubble can interact with the mesh on various points, which have been modelled in two main orientations. The first is inline, where the bubble comes at the mesh at the exact centre of an opening. In the other, the bubble comes in at the centre of a wire crossing. The effects of the mesh geometry are further elaborated upon in this study, comparing hexagonal and triangular meshes to the standard square mesh. For every mesh geometry, numerous bubble diameters are modelled to interact with the mesh and calculate the highest amount of deformation required for the bubble to get to the other side. The threshold Eötvös number gives an indication of the feasibility of this mesh geometry as it shows whether it can cut the bubble or not. This

h

threshold number is mainly dependent on the change in surface area over time, which boils down to a relatively simple geometry problem if the bubble volume is assumed to be constant, which is applicable in this case.

s

s

s

n=7

dw

H 2a'

2b

s

n=1

n=4 s

CMm s

s

n=9

2a

Iteratively solving for h and H in this case and calculating the surface areas of the daughter and mother cap yields a threshold Eötvös number for every possible scenario, and shows whether the bubble will get cut or get stuck beneath the mesh.

Conclusion

For both the inline and crossing configuration, the hexagonal mesh geometry shows the lowest threshold Eötvös number for a broad amount of bubble diameter to mesh surface ratios. This results in more effective reaction processes in these reactors, as more surface area of the gas comes in contact with the reactant liquid. Hexagonal mesh grids at this scale are however difficult to produce, so this is the next engineering challenge in improving bubble column reactors.

In conclusion, this Bachelor’s Final Project explored the influence of different mesh geometries on bubble cutting efficiency in gas-liquid-solid flows within reactors. The study, guided by Rahul Sabburaj and Niels Deen, highlighted the effectiveness of wire mesh in enhancing gas-liquid reactions by cutting large bubbles into smaller ones.

This research contributes insights into optimizing bubble column reactors, emphasizing the promise of hexagonal meshes for increased efficiency. Moving forward, addressing the engineering challenges will be crucial for implementing these findings in practical applications, fostering advancements in reactor design and operational efficiency.

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Tech

ENGINEERING AIRPLANES: MECHANICS

WRITTEN BY ARYAN BAKERMANS & DANIËL KLEINJAN

Dreaming of flying has been around for ages. At the end of the fifteenth century, Leonardo Da Vinci made drawings of a possible flying machine, based on birds and bats. Unfortunately, this remained a dream until the end of the nineteenth century, when the German inventor Otto Liliental performed many experiments where he would wear two major wings, run off a mountain and try to stay in the air, which he achieved successfully. However, the first motorized flight which did not need someone running off a mountain were the Wright brothers in 1903, they built an aeroplane with an engine that flew for only a maximum of a minute, but they managed to build a flying machine!

The experimental wings of Otto Liliental. Image by: Getty Images From these early pioneers who dared to dream of soaring among the clouds to the sleek, state-of-the-art machines that crisscross our skies today, airplanes have rapidly become a characteristic of the modern age, with the development of airplane technology being a testament to the ingenuity of us engineers. Within the design of modern airplanes, various mechanical engineeringrelated topics are included such as material science, aerodynamics or hydraulics. Altogether, airplanes truly are a

special creation. Therefore, the following article series will take a closer look at various aspects surrounding them. The real-life applications of an aircraft that will be covered will be related to the knowledge gathered from courses taught in the Mechanical Engineering major. In the first article of this series, the history of planes is reflected upon, and the first aircraft application will be elaborated. It features the “foundation” of an airplane: the landing gear.

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Tech

The Wright brothers’ airplane. By: Library of Congress So, what is it that we call the landing gear? Reflecting upon the early days, when aircraft looked like the drawing of a 3-year-old kid, the landing gear was designed similarly. With simple glider planes like the Wright brothers’ plane. With the mass of these planes only being 300 kilograms including the “pilot”, the landing gear didn’t have a high load to carry, thus it was made to glide

like someone put skis under the plane with a so-called “skidbased” landing gear. These “skids” were a piece of the airframe, meaning it was made out of wood and would wear out within a few flights. Luckily these planes were purely experimental so the airframes didn’t have to last long anyway.

Dc-3 “Dakota” representing a tailsitter

Douglas C47 (Dc-3) being loaded (Australian War Memorial)

Layout of legs

When planes developed further, their overall design changed quite a bit. The addition of wheels made the airframe last longer and bigger wings made for a more capable plane.

Descending from the larger wings, a more subtle difference was the placement of these wings, which moved further towards the tail as planes developed, which in turn influenced on the landing gear placement as well. It led to the change from being “tailsitters” as seen with the DC-3 Dakota, to having one gear leg under the nose of the aircraft, with the other two legs placed

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under the wings to form a triangular shape as seen in nearly all modern aircraft. This triangular shape is of course to provide stability to the aircraft, comparable to the fact that triangles are strong in the world of truss structures. This evolution in landing gear placement had no direct influence on the strength of the aircraft since this evolution was purely meant to improve stability, handling and the pilot’s visibility during takeoff and landing.

Tech

Hydraulic additions

Simultaneously, the landing gear became more sophisticated in terms of strength and functionality with the invention of hydraulic systems. Eventually, this led to the evolution from a static gear system as present under a Cessna 206 to a retractable gear. These changes made for a better plane in use and increased longevity. These systems were however more involved from an engineering aspect with concepts such as static mechanics, material science and dynamical systems playing a large role in ensuring that the gear could hold the increased weight of the planes.

Cessna 206 with static gear and a nosewheel layout.

By: Steve Hall

Structure and components

Schematic of a retractable gear system.

Calculation

So now what? To check whether a designed gear system is capable of holding the airplane’s weight, basic concepts from Mechanics are to be used. Truss calculations in particular.

In the figure on the left, a problem is set which we should be able to solve with our first-year knowledge of mechanics, which we dare you to try on the calculation space below.

After gaining the answer to the stated question, extra information is needed: the yield strength of this steel type is 250 MPa and we require a 500% safety factor on the strength so it won’t fail on landing. Will this landing gear hold or fail?

Answer: No!

In these modern-day landing gears, some basic components can be identified. When covering them from the ground up, we start at the wheels, whose size and quantity are usually dependent on the weight of the plane, with a higher weight leading to more and larger wheels. Within these wheels, the brakes can be found, which are designed according to similar variables. Afterwards, the main strut is encountered. This is usually a steel tube with a shock absorber embedded into it and is the part which has to carry all the load before distributing it over the multiple wheels per landing gear leg. The design challenge of the main strut in the landing gear is to ensure that the part doesn’t fail due to buckling under high load while maintaining the lowest possible weight. To help this main strut retain its stability, the downlock strut is attached at the side of the main strut, providing the mentioned extra stability. Additionally, the ability to have the gear retract and deploy using hydraulic systems can be embedded in these parts.

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Association

SNEK: A TASTY REVIEW Welcome to the world of SNEK, where snack lovers unite in pursuit of the ultimate snacking experience! Prominently present in De Weeghconst, the blue cabinet offers an array of tantalizing treats, each vying for your taste buds’ attention. From the savoury to the sweet, the crunchy to the chewy, SNEK houses a treasure trove of snack delights just waiting to be explored. In this article, we embark on a culinary journey to unravel the mysteries of our beloved SNEK, revealing the best and brightest amongst our delectable offerings. Join us as we dive into the scrumptious world of SNEK and rate these snacks to help you make the most of your snacking adventure.

WRIT TEN BY ELLE VAN HOUT Rating

The age-old debate of what snack is best wasn’t settled easily. To get the most opinions a survey was conducted in De Weeghconst.

In this survey, every member could tell us what their favourite snack is. The opinions were, as expected, very different among members. Eventually after around 50 votes, the debate was finally settled and the following snacks came out victorious.

In the following rating, the amazing snacks will be described together with the arguments as op why this snack deserves this high rating. We will start with the snacks that deserve a super!

(S) rating and then follow along to ranking from A to D. Within the Association we are very fond of foreign snacks. This

S can be seen by the two snacks that deserve a super rating from our members. The German Kinder Bueno and the Belgian waffle.

The Kinder Bueno is such a good snack for multiple reasons, its unique taste of a chocolate-covered wafer with a gooey hazelnut

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paste within. The combination of the crispy and gooey results in a delightful taste experience. The Belgian waffle also has this combination of textures and maybe this is why it deserves the super rating as well. The crispy sugar helps make an already great snack even better. A quick tip regarding the waffle, warm it up to enjoy the waffle even more!

A The snacks Th k deserving of an A rating are the Dove caramel chocolate bar and the YumYum instant noodles, specifically chicken flavoured. The chocolate bar is the perfect snack for a typical sweet tooth due to its already sweet chocolate that is made even sweeter by a filling of liquid caramel. The Dove even comes in two so it’s perfect for sharing, or treating yourself twice!

For a more savoury snack, which is honestly the first course of a lunch, the instant noodles are a perfect option. The noodles can even be enjoyed in more than one way, as just noodles or even

Association as noodle soup! The people around you probably won’t like you as much due to the smell but apparently, that doesn’t influence this snacks rating.

B The snacks with a very respectable B rating are the Twix and the M&M’s peanut. Both of these snacks are share-sized so easy to enjoy with friends while taking a break from studying. With the Twix, you might get the argument about what side is better.

No matter which one you’ll get the caramel, wafer and chocolate will result in a wonderful treat. The M&M’s are a tad more savoury but very tasty nonetheless. Of all the M&M’s these are rated the best because of the great sweet and salt combination of the roasted peanut, the chocolate, and sweet coloured cover.

C Further down the rating, we get the more savoury food. For the C rating, we have the Bapoa and the Cup-a-soup tomato

New snack

From the survey conducted with our members we might be able to conclude that they don’t want to bring their own lunch.

When asked what other snacks our members would like to have to their availability the most mentioned one was the VlamTosti.

The VlamTosti consist of two slices of casino bread with cheese and spicy beef in between. As a student you’re busy with a lot of different things so it is understandable that you don’t want to think of anything else which might be why lunch is often forgotten. If we were to have VlamTosti’s in SNeK this would

flavour. The Bapao is a great alternative if you have forgotten your own lunch. In only 2 minutes this Chinese steamed bun is ready for consumption. What makes the Bapao even more liked is that you can choose between chicken and beef so there is something for everyone. The cup-a-soup is a good snack due to its convenience, you only have to boil some water and the soup is instantly ready. Due to the salt in the cup-a-soup, it’s also a great remedy for a possible hangover!

D Further down the rating the votes get even more divided so 3 snacks will have to share the D rating. Last, but not least, snacks we will mention today are; Snickers, Bolognese chips, and Mentos. Snickers is a great snack because of its flavour combination and because it is so satisfyingly filling. Perhaps if it weren’t the most expensive snack in SNeK it would have rated higher. The other two snacks might go hand in hand, the Bolognese chips are great in general but after you might just need that mentos to refresh your breath.

take away one more worry and make our members’ lives a bit easier. In just a few minutes the tosti is ready to eat and you can continue to work on your deadlines.

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Education

by TEAM V ARCHITECTEN

GEMINI-N | OUR FUTURE HOME WRITTEN BY STEFAN GEERTS

The commencement of one of the most significant renovation projects in TU/e’s history is now in full swing. Initiated by the approval of the new Gemini building’s final design in 2022, the contractor Heijmans arrived earlier this year starting a new phase of the physical part of the renovation. To get to know more about the current state of the renovation, we spoke to Vione van Leeuwen. She has been a project leader at Real Estate TU/e since March 2022 and is responsible for the interior of the renovated Gemini buildings.

Design

Similar to Atlas and Neuron, the new Gemini is designed in collaboration with Team V Architects. The goal of this design is to create a more flexible work environment for the students and staff of ME and BME while keeping the well-known characteristics of the original Gemini. As Gemini prepares to welcome a large and diverse group of students and staff, the challenge of harmonizing various requirements into a single design presents a sizable task, according to van Leeuwen. She explained, “Engaging with representatives of the end-users at every stage of the design process allowed for the architects to integrate their feedback into a design that accommodates the needs of all.”

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An example of this is the mockup on the first floor of GeminiSouth. “This mockup serves to demonstrate and evaluate the office setup with the ‘train seat’. The office located behind the train seat offers a working space for two colleagues. If either person needs to have a consultation, they have the option to step out and use the train seat to meet or to continue their work.”

Special effort was put into the acoustic treatment of these train seats and the building in general. “The architects made a design which was then analysed and improved acoustically to ensure a comfortable work environment on all floors.“

The characteristic concrete columns will stay visible throughout the building. “By using a design like the train seats, the original structure can be kept in place while providing a new and optimized workspace. Together with a more open interior and the use of greenery walls, the building will look completely new with a touch of heritage.

by EX-INTERIORS

Education Demolition

The renovation started with the dismantling of almost all facilities in Gemini North. “This process was not as straightforward as normally due to the multi-phase plan for Gemini”, van Leeuwen told us. “Due to Gemini South and even multiple labs in Gemini North staying fully operational during the dismantling phase, every step had to be taken with caution. The labs require a vibration-free environment to function. This meant we had to constantly monitor the building for vibrations and work mostly outside of office hours.”

There was also very close contact with the staff still working in Gemini South. “Of course, a renovation will always come with unwanted noise, but that is inevitable. We tried our best to stay in good communication with both faculties and come up with smart methods to limit the vibrations. For example, all walls were torn down with the use of tires to soften the fall.”

The demolition stage has now been completed and the rebuilding has started. The experiences from the renovation in Gemini North will be of good use for the future dismantling of Gemini South. At that time, students and staff will be making use of Gemini North already.

by TEAM V ARCHITECTEN

Building layout

Gemini North will mostly house meeting rooms (for CBL meetings), 4 half-size lecture halls, multiple labs and PhD and graduate candidate workspaces. “This big mix of users comes with a big mix of needs. In the architectural plan, there were large working spaces for multiple types of students.

In the formed interior advice team, which contains a delegation of all types of users, this idea was revised to fit better with the needs of the end-users. This shows the importance of advisory teams like this one.”

On October 31st, the Gemini exposition was officially opened. This exposition, showing the plans for Gem-N and Gem-Z, is open for all employees and students to visit. “We are working hard on improving the information channels to both students and staff about the current status of the renovation. When Gemini North is finished, this exposition will move to that building to show the progress on the construction in Gemini South” , van Leeuwen says. “We are also working on a realtime information display in the exposition, where we can post the most up-to-date information regarding the renovation.”

by Levi Baruch

Next to the educational spaces in the building, there will also be room for leisure. Both student pubs will be housed in Gemini North with a special inside-outside space.

“You can consider it to be a flexible and tailor-made suit”.

There will also be regular study space and multiple seating areas where you can get coffee and relax in between lectures.

Future

With the current timeline for the construction of Gemini North, it will be completed around Q3 of 2025. At this time, the staff and students of Gemini South will be moved to temporary housing around the campus and former Fontys buildings just outside campus. After this, the renovation of Gemini South will start. “Gemini South will house facilities like the reception, restaurants and larger seating areas. It will also house both main entrances, one on the Green-strip and one opposite Neuron.”

The most up-to-date information on the renovation will be uploaded to multiple channels. The Newsletters of both departments will contain more regular updates on the renovation, as well as the Intranet page of the Gemini building.

Furthermore, the exposition on the renovation will serve as a dynamic information area with the most recent updates.

In the coming openMEs, we will look further into the labs that will be housed in Gemini, as well as our members room!

by TEAM V ARCHITECTEN

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TU/ECOMOTIVE: SHAPING THE FUTURE OF SUSTAINABLE MOBILITY TOGETHER WRITTEN BY IMKE GOOFERS

Far, far away, at the very end of the TU/e campus, there is this place. A place where hard work is delivered, nothing is impossible and where dreams come true. A place where it is always ‘gezellig’, where flunky ball is a real sport and where you can make a delicious tosti during every break. One building, six student teams: you can say that something exciting is always happening in Momentum. This year, I am part of TU/ecomotive: the student team that aims to shape the future of sustainable mobility together.

Tech Concept cars

Over the past ten years, TU/ecomotive has built eight concept cars with eight different teams, consisting of team members from different backgrounds. Around the start of every new academic year, a new team starts with their new concept and with the goal of realizing this concept within one year. To achieve this, there are four big phases the year consists of the concepting, designing, manufacturing and building phase. To close off the year, a big promotion tour is organized. Last summer, the eighth team toured through Europe with their car Eterna: the car that lasts a lifetime.

Eterna

Eterna was designed and built in only one year by 30 students.

Similar to the other cars that have been built before Eterna, with the goal to make the industry and public think differently about the development and use of cars. Eterna showcases a way of using materials more efficiently by separating the lifecycle of a car into two lifecycles.

Two lifecycles

But how does that work? Most materials in a car are still far from depreciated after 20 years, yet the average car is heading towards the scrapyard then. This is why Eterna consists of a durable bottom for long-term use and a swappable top. The bottom includes longlife components such as the ladder frame chassis, batteries and motor. The swappable top consists of materials with a shorter lifespan, such as interior fabrics and safety features (e.g. digital side mirrors and cruise control). By separating the lifecycles of the top and bottom, the optimal lifespan of both cycles is utilized.

As a result, the emissions during the production process are reduced by a third.

New team, new concept

Currently, I am part of the ninth team of TU/ecomotive and I have very much enjoyed it until now. I think that it is really cool to be part of a team that is really motivated to achieve a next-level goal.

I get a lot of energy from working together with my teammates and having fun together every day. My advice: go take a look sometime, at the student teams. And if you have found one that you like, go for it.

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Association

BACOLUMN

THE RUM RENAISSANCE!

WRIT TEN BY THOM ENGELENBURG & PIETER PANDER

The Renaissance was a fervent period of cultural, political, and financial ‘rebirth’ in Europe. Man came from the dark ages and saw the light of science. Italian philosophers introduced new ideas like humanism and secularization.

Slow and steady the general motto of the populace began to shift from ‘Memento mori’ (remember that you will die) to ‘Carpe diem’ (Seize the day), finally life became more than waiting for death.

In the transition from the dreaded corona period to now, the Association has experienced its own rebirth. Streams were replaced by actual lectures, much to the displeasure of the seasoned ‘borrelganger’. However, in times of change and turbulence new ideas thrive. We might have lost our two hours of extra sleep and pantless lectures,

Carabica White rum

First of all the Carabica White rum was tested, this was the cheapest rum we could find in the Gall&Gall. From the outside it can be determined that this rum was not made to be good, just to be rum.

but we gained something very valuable: A new rum for in the bacos!

Due to the introduction of new prices, Captain Morgans Spiced Rum became just as cheap as Boots Rum, our rum at the time. During the years questions arose if the BACo made the right choice. Could we have done better? In this article, your beloved friends from the BACo will test a set of rums and see if the decision made by mr Pander was legitimate. (small flash-forward, it was!).

All rums will be tested on a selection of topics. First of all, the flavour. Then the smell and the ability of the rum to perform paired with cola or as a single shot. Then the overall quality will be determined.

Carabica Dark & Strong

After the Carabica White, the Carabica Dark & Strong was up. This is the brown step-brother of our previous subject. It reminds me of Boots rum, the rum that was featured in the bacos before we made the switch to Captain Morgan. We were getting very nostalgic.

Flavour

1

The flavour sits between water and cleaning alcohol.

Smell

3

The smell backs up the thesis that this is secretly cleaning alcohol.

Flavour

3

It tastes like someone put a piece of wood in a bottle of Carabica White and left it for a week. It just tastes like someone would take the colour brown and imagined what that should taste like.

Bacobility

6

The cola does its work perfectly, it blooms the taste of the rum. When you add a small slice of lemon it is even drinkable.

Smell

4

Smells like the Carabica White with a whiff of tree.

Bacobility

7

This reminds of the bacos of old, it is actually very similar to Boots Rum, the rum we were raised on.

5

Other than the Carabica White this goes down like there is 80 percent of alcohol in it. The piece of wood mentioned in the flavour section was apparently real and brushed our throats.

5

This is a watered-down version of Boots, it could be that the current testers got a bit nostalgic and rated everything higher than necessary. But hey, we were already two bacos deep.

Shot

Overall quality

7

Because of the weak taste there is no aftertaste. If you are used to Bokma this is child’s play (18+ of course).

3

If you are looking to get drunk cheaply and have the hangover of a lifetime afterwards, this ‘Chateau Migraine’ among rums is your best bet.

Shot

Overall quality

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Association Bacardi Carta Blanca

As the scientifically inclined people we are, we can not leave out the classic: Bacardi Carta Blanca, the go-to rum of every bar on Stratumseind. If you think baco, you think Bacardi.

Flavour

4

You can really taste that this is a good rum, however white rum tastes bad most of the time. In contrast with the cheap Carabica White, this does have a taste other than rubbing alcohol.

Smell

4

The smell does remind of underage drinking in a field, but if that is necessarily good is a debate to be held another time, maybe in De Weegh while enjoying a nice baco…?

Bacobility

Shot Overall quality

7

Not excellent, not bad, just good. It tastes like a baco on Stratumseind. Mister Pander thinks it tastes like the many evenings he spent with his father drinking bacos in the kitchen until 8:00 in the morning.

3

This is not made for shotting purposes, please just use this as a mixer.

6

In essence, this is a good quality rum. It is not made to really enjoy however, this is your standard Stratum-pub rum. It’s not great, but it’ll get you there.

And then, last but not least, in the left corner, fighting for De Weeghconst since 2021, Captain Morgan Spiced Rum! This rum has paced itself in the cupboards of De Weegh and in the harts of the members.

Bacardi Carta Oro

Staying in the Bacardi theme, we now move on to the Carta Oro. This is the masterpiece of the Bacardi family. Aged in charred wooden casks this rum not only tastes good, it looks good as well (and expensive).

Flavour

8

Tastes like gold, the wooden casks used to make this concoction are very much present in the palette.

Other than the Caribica Dark & Strong it has depth in its taste, almost like a whiskey.

Smell

8

This is the first rum that does not hurt your nose with its alcohol. You can smell wood, sugar and quality.

9

This is a brown rum, like the Boots of old, and tastes similarly. This is no ‘slim chugging baco’ you get at the Peppers, this baco deserves the respect of drinking it slowly and tasting it well. Chugging this would be considered a hate crime in Cuba.

Shot

6

Due to the wood tones the alcoholic taste arrives late. The aftertaste reminds of a mellow, cosy wooden cabin. However, this is not a drink you can shot much of before it really gets hard. Because of the abundance in taste, your system would get overwhelmed; better to drink Bokma.

Overall quality

8

Gold

Bacobility

Flavour

It tastes like Carta Oro but with spices. There are tones of vanilla and charred wooden casks. Just as you would get happy of speculaas and 10 peperkoek, this reminds of warm cozy feelings. However I would rather put Captain Morgan in my cola than speculaas and peperkoek.

Smell

Smells like home. Most rums smell like wood and alcohol, this smells like 10 spices and love.

Bacobility

Perfect blend of rum and cola. It captures the best of both worlds, with a sweet cola side and a caramel-vanilla touch from the BACo. It's a 10 masterpiece; if Michelangelo were in the BACo, the Venus de Milo might never exist – this would be his magnum opus.

Shot

The spices make you forget that what you are drinking is actually alcohol.

10 The sweetness counters the alcohol taste perfectly.

Overall quality

This Captain has sailed his way into the heart of the entire BACo, we could 10 not live without it.

In a few years, when we can add the two beautiful letters ‘ir’ to our names, we can look back on our time in De Weeghconst as a time of friendship and pleasure. The first drink after a long week of writing SSAs, ploughing through tough lectures and breaking your head over differential equations tastes like home.

Next time, if you happen to find yourself at the drink and don’t know what to order, think of the time spent to perfect the baco and order one for you and your friends. Taste the love that the BACo puts in this simple cocktail, and spread it to the rest. After all, we need to remember the motto of our time and ‘Carpe diem’!

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Tech Te T ec ech ch h

EIGENFREQUENCY OF...

A BEER KEG WRITTEN BY BEN GORTEMAKER

In the previous edition of measuring eigenfrequencies, we looked at various objects in the Association room. This was done for no particular reason except out of pure curiosity.

However, this edition will be a bit different as this time we will be looking into the eigenfrequencies of a keg, and this time it is for a very good reason If you ever have looked a bit closer at the bar in De Weeghconst you might have noticed something called the BACorakel. The purpose of this apparatus is to show how full the current keg is, and if you might need to get a new one soon, something that is quite helpful for the C0BA. Or nice to know how much is left over of the free keg. This apparatus was made in 2013 by Tiemen And has helped the BACo draft beers for over … years. However, since the rehousing to Traverse at the end of 2021 this beautiful apparatus has been broken. This is because the BACorakel used a scale to measure the weight of the keg and with that determine the amount of beer that was still left in it. However, when moving to traverse we started using a keg cooler instead of a cooling loop. In this new keg cooler, there is not enough space to place a scale beneath the keg thus making it impossible to weigh the kegs. For this reason, the BACorakel has been dysfunctional ever since the rehousing to Traverse. To repair the BACorakel we need a new way to measure the fullness of a keg. For this, there are three possible solutions: 1.

2.

3.

Creating a low-profile scale.

Keep track of fullness using a flowmeter.

Measure the eigenfrequency.

Making a low-profile scale would be an easy solution to the problem. However, making a scale that is very robust, watertight, and low profile is quite a big challenge. And it would mean that you would lose some amount of height in the cooler. Which would make placing kegs inside of the cooler more difficult.

Therefore, using a low-profile scale would be a good solution, however, using a solution that does not use height in the cooler would be preferable.

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The second solution would also work very well. However, it would take some more user interaction to keep track of the fullness of the scale. A flowmeter does not know when you replace a keg, and therefore some input is needed to replace a keg. On top of that in the case that power is lost to the system it would lose track of the fullness of the keg. Making it less robust than a system that directly measures the fullness of a keg.

Then the last possible solution to this problem would be measuring the eigenfrequencies of the keg. Measuring the eigenfrequency would only require exciting the keg at certain frequencies and measuring the response. This could be done in a contraption that does not interfere with anything inside of the keg cooler. Making this contraption will be done at a later date because in this article we will look into the viability of using this solution. We first take a look into the theory, then look into the test setup and the results of this experiment.

Theory

From high school, most of us know the theory of resonant frequencies in a tube. The theory is that in a closed tube, the resonant frequencies will be determined by the standing waves that are possible. With the fundamental tone having twice the wavelength of the length of the tube. Then using the speed of sound of the medium you are in you can compute the fundamental tone. Next to that, you can compute n higher resonant tones with that, using the following equation: (v*n)/2L In a keg, we have the same case. But in this case, you are dealing with two fluids in one tube. However, using the fact the transfer

Tech of sound from air to water and vice versa is not very high, we can assume that that the interface between these two fluids can be modeled as a solid wall. This means that the complete model of the eigenfrequency of a keg can be modelled as two cylinders which are closed at both ends with a moving wall between them.

Then there are two possible eigenfrequencies in each given volume. One moves vertically between the moving wall and one horizontally. These both can be predicted with the standing wave equation. Plotting this information gives us the following prediction of what the eigenfrequency versus keg content plot should look like.

The test setup

Now we know the relation between the fullness of a keg and the eigenfrequencies of the keg we can start making the test setup.

The most important thing is that we want to be able to isolate the sound that the keg is making from the noisy environment.

To do this we will be using a contact microphone. There are plenty of these available on the internet, however, they can also be easily crafted yourself. In this case, it has been done by wiring up a piezoelectric speaker as a microphone hooking it up to a smartphone or tablet, and then using an app to analyse the data.

Then the keg is weighed and hit with a hammer to ring it like a bell whilst we are measuring the keg with our homemade contact microphone.

Fig 2: The contact microphone during the drink. However, some of the data seems to line up reasonably well. The data itself still had a lot of noise and it was not easy to filter out the resonant frequencies. There were many faint higher-order resonant frequencies and a lot of variation between measurements. This happened because when the keg changed, the attachment of the microphone was different.

The data show a promising relation between the mass and resonant frequencies; however, a more consistent measuring setup is needed.

This setup has one problem and that is that the keg has to be taken out of the keg cooler during a drink. This makes taking measurements very difficult as during a drink there are plenty of things to do other than taking measurements. For this reason, I expect that not a lot of measurements can be taken. However, the concept can be proven to be useable, which is the goal for the time being.

Next steps

For later setups, a more refined setup is needed to completely tune the system.

Next to that, the setup needs to focus on a more limited range of frequencies. The higher frequencies seem to be very faint and not very usable for accurate determination of the eigenfrequencies.

Then after a robust measuring setup is made an easy and robust implementation needs to be made that does not take any interaction from the BACo.

Results

During the drink, it was possible to only take 5 measurements and they can be seen in the next figure. This is way less than ideal, but it was too difficult to take many measurements

Fig 1: Theoretical eigenfrequencies

As said before, a more consistent measuring setup is needed to get good results. Mainly a setup that can take many measurements during the drink is needed such that the frequency profile of the keg can be figured out. After the frequency profile is figured out it can easily be tuned to the mass of the keg with only a couple of mass measurements.

To be continued…

Fig 3: Results

20

C reer Ca Career

INTERVIEW SETTELS SAVENIJE

Imagery by Settels Savenije

WRITTEN BY STEFAN GEERTS

Located in the former pumping station (pompgebouw) at Strijp-T is the Settels Savenije group of companies. We were invited to visit and to talk with both Jaap Oudes, one of the principal mechanical engineers and with Jordy Cuijpers, recently graduated from the TU/e and now working as a design engineer in mechanics at Settels Savenije.

Settels Savenije - A group of companies

The Settels Savenije group of companies specialise in high tech, handling the full design cycle for high-precision parts for OEM customers. Their state-of-the-art facilities allow them to invent, design, industrialise, manufacture, assemble and test high-tech products, modules, tools and equipment.

When you step into the main building you are immediately immersed in the essence of Strijp-T. You walk between enormous pipes, part of the original function of the building, which are interspersed with modern display stands exhibiting innovative precision parts and from any place you stand, you have large windows looking out to green spaces. Old meets new: the interaction between the historical, the contemporary and the future. The staff are often quoted as saying that when they work in this building they just “breathe technology.” It is a very inspiring environment in which to be, both as a visitor and as an employee.

The pumping station was originally used to purify the water used in the Phillips factories in Strijp. It was completely renovated in 2016 and further extended in 2020 to now house 8,395 m2 of cutting-edge industrial premises.

The company evolved from a research and development company to include in-house precision parts manufacturing from 2010 and advanced systems manufacturing from 2016.

Currently, Settels Savenije has around 150 FTE of staff divided 50-25-25 across the abovementioned categories.

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With their specific know-how and experience and the relative technical assets, Settels Savenije are at the forefront

of technology. They provide high-precision solutions to international high-tech clients such as ASML, Thermo Fisher and VDL ETG. Add to that their no-nonsense mentality and their ability to provide the full design cycle to clients, it is obvious that Settels Savenije is a very special employer in the Eindhoven region.

Career

Jaap Oudes (left) Jordy Cuijpers (right)

Road to Settels

We asked Jaap and Jordy how it was that they became involved with Settels Savenije. For Jaap, this started with his graduation project when he was supervised by one of the founders of Settels ( Jan van Amelsvoort).

“As a continuation of my education in Mechanical Engineering, Naval Architecture and Business, I started my professional career in Eindhoven at Philips CFT. That was up to 12 years ago, when I was surprised to meet my old supervisor at a vegetable stand in the Woenselse Markt. Jan’s opening line was magnificent: “Isn’t it about time you come to Settels?” From that moment, our friendship revived, and we were happy to have found each other again, getting to know and respect each other even more.

There was a lot to catch up on after all those years. And I went to Settels...”

During his time at Settels, Jaap has fulfilled both technical and management functions and is now mostly busy with transferring knowledge to the new mechanical members of the Settels team.

“Every young person who comes in here and wants to learn the trade will definitely come by my desk to have a talk about what they want and need.”

One of these new employees is Jordy. “I started as a Mechanical Engineer from Fontys. After working at Philips Innovation Services, I continued my education with a Master’s degree in Mechanical Engineering at the TU/e. Specialising in the Microsystems research group, I developed the skills that I now use at Settels as a design engineer in mechanics.”

“The project I am currently working on requires us to build a device that transfers a small force with a large stroke to a large force with a small stroke”, Jordy explains.

“The additional requirements that a client gives us, such as volume or manufacturability make these types of project a big design challenge.”

“We start by building a functional 3D print of the CAD design. This print enables us to verify the functionality of our concept and support the manufacturability discussion.”

Placeholder project

Full design cycle - total solution provider

What makes the work of Settels Savenije special? we asked.

“The most important thing we are looking for within Settels Savenije is to keep a full design cycle integrated in the company culture. When designing challenging solutions which are on the edge of what is possible, you should be constantly evaluating the product on multiple levels,” was Jaap’s reply.

Jordy continued: “When designing a part, you can easily have a chat with the production department in the other building.

When they hold your first precious 3D printed prototype, they immediately start analysing the production feasibility and thinking of solutions to create a reproducible manufacturing process. With this type of collaboration, you minimise the amount of design loops, which in turn saves valuable time.”

“You need to have perseverance in direction, but stay receptive to change, to fit in our engineering world,” Jaap continued. “The passion for design and collaboration skills have to be there from the start to work the way we do.”

“The expertise that we have here is consistently valued,” Jordy continues. Jaap adds: “Mastering a skill takes a significant amount of time. Even a seemingly simple technical drawing can demand a wealth of experience and knowledge to be executed well. This is why our trade still thrives on a substantial degree of craftsmanship.”

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Career A day at Settels

“You are assigned a project with a certain group of engineers,” Jordy explains. “The composition of the group may change, depending on the project, as can the number of projects you are working on simultaneously. The first step is to identify the client’s needs. Sometimes, you may end up speaking to someone other than the engineer responsible for the project that you’ve been assigned to. In such situations, additional input may be required.” Jordy continues: “A vital aspect of providing a valuable solution to a client lies in truly understanding what they desire.

This necessitates stepping into the client’s shoes, thinking alongside them, and knowing precisely which questions to ask … We occasionally find ourselves helping the client discover what it is they truly need.”

Summing up, Jaap concludes: “If you combine your own creativity with the discipline and perseverance you’ve acquired along the way, you can achieve remarkable results.

Witnessing other engineers find innovative solutions to challenging problems, even when I’m not directly involved, brings me immense satisfaction. That, is the essence of our profession.”

“Koersvast en zijwindontvankelijk” “Perseverance in direction, yet graceful in navigating the winds of change.”

The future A day before our interview, Settels Savenije acquired the van Mierlo engineering firm, further increasing its skillset and manpower to create the avant-garde future.

Settels Savenije is trailblazing up to the minute solutions, constantly upgrading and expanding their premises to increase efficiency and capacity.

This group of companies, on the edge of the green belt at the far corner of Strijp-T, is definitely worth a visit, during and/or after your studies and is a very interesting firm for future engineers.

Concluding We express our thanks to Jaap and Jordy for telling us about their experiences at Settels Savenije.

We hope that you as a reader have found out a bit more about the companies and what it is they excel in.

If you want to know more about Settels Savenije or to keep up to date with their news or job vacancies, make sure to visit www.sttls.nl

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BȲȰǥȨǡǞǛ FǤǟȲǡ PǛǞǣȨȰǙ System Identication for Cooperative Adaptive Cruise Control During the last 2 quartiles of the previous academic year, I completed my Bachelor’s Final Project in the Dynamics and Control Group. For this project, I was under the supervision of Dr. ir. A.A.J. Lefeber and ir. R. de Haan. The main objective of this project was to identify the longitudinal vehicle parameters of a Renault Twizy electric vehicle, which is used by the automotive lab for selfdriving experiments.

WRITTEN BY S

G

Education As the title of my BFP suggests, my research was focused on providing an accurate vehicle model of a Renault Twizy car, used for Cooperative Adaptive Cruise Control testing.

Let’s start with the last part, Cooperative Adaptive Cruise Control or CACC for short.

For an electric vehicle, the model is simple; you input a certain step with a certain step size which is used by the car to either accelerate or decelerate. The way the vehicle does this can generally be described by a first-order plus time delay model (FOPTD).

What is CACC

Adaptive Cruise Control (ACC) has been around for several years, getting installed in most, if not all, new (electric) vehicles.

It has been proven to improve both safety [1] and efficiency [2] on highways. However, ACC also has pitfalls that can cause dangerous situations when the driver does not immediately anticipate.

For example, ACC systems designed to maintain a fixed following distance may not be string stable [3]. In such situations, disruptions in the following distance among vehicles, resulting from delayed response times of non-leading vehicles, are amplified when propagating along the vehicle string. The delay in response time, which is also observed with human drivers, can lead to unpredictable traffic jams or, in extreme cases, rearend collisions.

The FOPTD signal above ( y(t) ) is activated by the step input u(t) with stepsize A. As you can see, there is a delay between the start of the step input and the start of the FOPTD signal. This is what we call the delay (L). This delay can be caused by a lot of factors but is almost always present in a small amount.

Secondly, the end value of the FOPTD signal is not the same height as the input u(t). Instead, it is multiplied by K, which we call the gain (K). This gain is present in every signal and can be accounted for when known.

Lastly, the y(t) signal takes some time to reach its final state. This time can be a time constant which we call tau. A lower tau means a steeper slope and a quicker response.

Cooperative Adaptive Cruise Control (CACC) is a more advanced version of ACC, utilizing Vehicle-to-Everything (V2X) communication. In contrast to ACC, which uses Radar, Camera, and/or LIDAR sensors to determine the range to the preceding vehicle, CACC additionally employs feed-forward in its controller that incorporates the leading vehicle’s data like (desired) acceleration and velocity, enabling the system to anticipate instead of react [4].

To be able to know how the vehicle will react to certain inputs given by the CACC controller, you need to know how the vehicle will react to any arbitrary input. That is what the vehicle model is for.

The theoretical vehicle model

To know how to find a vehicle model, you first need to know what a vehicle model is. The fact that my testing vehicle, a Renault Twizy, was fully electric, simplified the model a lot. I did not have to take shifting, engine torque and other hard-to-predict features of gas engines into account.

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All three of these parameters (K, tau and L) need to be identified to be able to determine the vehicle model. For a clean signal (like in the figure above, this can be done via the following transfer function. The output G(s) is influenced by the gain (K), time factor (tau) and delay (L) via a first-order transfer function with a time delay.

The realistic vehicle model The model described above is made in Matlab Simulink, using a clean input signal with a clean FOPTD model. However, this type of data cannot be collected from real-world testing. The measurements taken from the Renault Twizy vehicle are very noisy and do not exactly follow a standard FOPTD curve. To be able to determine the vehicle parameters, a smart solution was needed. This is where the power of my beautiful HP Z5 notebook was of perfect use.

Education

The end goal of the project is to find one vehicle model that describes the vehicle in every circumstance. To do this, I tested and drove multiple hours with the Twizy, controlling it via my laptop on a closed testing road. By testing different stepsizes, step lengths and step directions, a full image of the vehicle response was collected.

The data gathered from testing looked a lot more like the figure above. With signal noise and vibrations in the vehicle, the acceleration data gathered from testing was not usable with the previous vehicle model identification method.

Instead, a program called EzyFit was used. This MATLAB software fits a curve with a pre-described function to the data that you provide. This was perfect for my problem! By rewriting the transfer function to a continuous-time function, I could find the required vehicle parameters for multiple tests with the click of a button.

By comparing the data from 100+ experiments, a final model of the vehicle with an 88% fit was found. This data was used to define the final vehicle model, which could then be used to tune the CACC controller for safer and more comfortable driving in platoons.

What I learned from my BFP

As I worked on your Bachelor Final Project, I started to notice that only part of the project was about the theoretical question I was given. More than ever before I was challenged to overcome problems and difficulties by myself. Since there is no aboveaverage CBL group member as backup, this requires a lot more effort than the projects I completed before.

This process felt frustrating or sometimes even impossible. 20 weeks (the time I got for your BFP) felt like an eternity when stuck on that specific MATLAB error that you seem to be having as the first person in the world.

However, when the 20 weeks were up and I survived multiple late-night work sessions and frustrated WhatsApp messages to friends having similar issues and doubts about stopping this BFP and starting over, handing in my final report was one-thousand times more satisfying.

References

After discovering this, a new question arose. Would the vehicle react the same to inputs of different sizes, lengths and with different starting speeds? Would accelerating from a standstill be the same as with a starting speed of 10 kmph? And would deceleration follow the same vehicle model but turned upside down?

[1] S. Miyata, T. Nakagami, S. Kobayashi, et al. “Improvement of adaptive cruise control performance”. In: Eurasip Journal on Advances in Signal Processing (2010).

[2] Y. He, et al. “The energy impact of adaptive cruise control in real-world highway multiple-car-following scenarios”. In: European Transport Research Review 12.1 (Dec. 2020), [3] S. Sheikholeslam and C. Desoer. “Longitudinal Control of a Platoon of Vehicles; III: Non-linear Model”. In: PATH research report (1990) [4] J. Ploeg, et al. “Design and experimental evaluation of cooperative adaptive cruise control”. In: 2011 14th International IEEE Conference on Intelligent Transportation Systems (ITSC).

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Education

fltr Tessa van Ecken, Isabel Rutten, Thijs Vernooij, Lieke Janssen

FEDERATION OF STUDY ASSOCIATIONS EINDHOVEN WRITTEN BY TESSA VAN ECKEN

My name is Tessa van Ecken, I’m a 5th year student Medical Sciences & Technology and I did a board year as President of the Federation of Study associations Eindhoven (FSE) last year, which I will tell you more about in this article. I’ll take you on a little trip down memory lane, while I explain to you what a board year at the FSE entails.

How it all started

The journey of becoming a board started around Christmas break when I visited the ‘Board Interest Lunch’ of my study association, SvBMT Protagoras. Yes, your beautiful neighbours. Besides getting information about a board year at the study association itself, there was also a presentation about the FSE. But what is the FSE and why is it interesting for a study association like W.S.V. Simon Stevin to promote this?

What is the FSE?

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Well, as it is already in the name itself, the FSE represents all 11 study associations of our university. From W.S.V. Simon Stevin of Mechanical Engineering to Lucid of Industrial Design and everything in between. As umbrella organization, we’re in contact with different parties. The most important task is to stay in close contact with the boards of the study associations, in this way, you know what is happening within the associations, in a formal and informal way. Study associations are basically all the same,

but for different studies and thus different students. This results in the associations looking differently at specific topics, learning and inspiring each other. This happens during the umbrella meetings, we have a monthly formal meeting with all the chairmans, called the AB-meeting (‘Algemeen Bestuur’, General Board). But besides that, we also have divided some topics into working groups, or so-called portfolios, so that the correct board member of each study association can join that specific meeting.

Think about brainstorming about new initiatives or solving problems in the field of career, education, bars or well-being. As a board member of the FSE, you mainly host these meetings for your own portfolios. You’re also in contact with other umbrellas of our university, the university itself and even with other universities! You’re actually the link between the study associations and everything higher up. Here, you work on bigger topics or events, like the Introduction Week or sustainability.

Association How it all started

After hearing this story and talking to the board of my study association, I was convinced to start a board year at the FSE. Around summer break, you get to know all the boards of the study associations. It is really interesting and fun to actually expand your horizons and to get to know new people from different associations and studies since everyone is different. Besides having some serious meetings, there is also a lot of time to do fun things, like having a drink with board members of different

associations or visiting their activities. You also organize some nice activities together.

Activities

Future

At the beginning of the year, a working group consisting of board members from different boards is formed to organise the FSE-day, better known as the BorrelXL. This drink always takes place in May, when we bring together all the study associations and just have a fun evening with each other. This is also a kind of reunion moment for a lot of people; seeing people from high school or your fellow old board members again. Another highlight of the year is organizing MomenTUm the Party, which is the evening before the graduation ceremonies at the end of September.

A prime example of this type of collaborative activity is the Bokma Drink, organised by the new Board of Simon Stevin. Here, all boards come together to enjoy their association drink; Jonge Jenever. Bonding with the new boards is the most important step towards a successful board year at FSE.

And with that epic end of your board year, you can hand over your tasks to the next board, just like I did. This year, Bas Jansdam, a member of W.S.V. Simon Stevin, is in daily board of FSE. If you would like to know more about the FSE, feel free to contact him or the board of W.S.V. Simon Stevin!

See you soon in De Weeghconst, Tessa van Ecken

federation of study associations

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Tech

MAPPING THE STARS The Euclid telescope, launched in July, aims to create the largest-ever cosmic 3D map over the next six years by observing billions of galaxies up to ten billion light-years away. The mission, led by ESA, seeks to unravel the influence of dark matter and dark energy on the formation of the universe. The Euclid telescope is a crucial complement to the Hubble telescope, alongside the James Webb telescope. While the James Webb excels in detailed study of small sky areas, the Euclid’s broad-view capability allows it to capture large portions of the sky at once, providing a comprehensive perspective.

On the 8th of November, the first images from this telescope were revealed.

The Horsehead, resembling a horse’s head and located approximately 1375 light-years away, stands as the nearest giant star-forming region to Earth.

Positioned just south of the star Alnitak, the easternmost in Orion’s renowned three-star belt, it forms part of the expansive Orion molecular cloud.

While numerous telescopes have previously photographed the Horsehead Nebula, none rival Euclid in producing a single, sharp, and wide observation. In just one hour, Euclid captured this remarkable image, highlighting the mission’s exceptional capability to swiftly capture high-detail images across an unprecedented expanse of the sky.

WRITTEN BY STEFAN GEERTS

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ESA: Euclid’s view of the Horsehead Nebula

Tech

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Association

St: What happened to

mopeds?

If there’s one development in 2023 that you can’t get around, it’s the fatbike.

Adolescents of a wide range of ages whiz past you on bike lanes with a somewhat ugly, but apparently functional electric bike that has been illegally tuned to 50 kilometers per hour to ensure speedy transportation. Apparently, these devices are so popular among the youth that city council members are now calling for license plates and a minimum age requirement1, such laws already exist for conventional mopeds and scooters. Still, as a mechanical engineer, I wonder: where have the traditional 2-stroke mopeds gone in general?

WRITTEN BY JOOST VAN DER KRAAN

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Association

It’s already been four years, but the memories of my high school period are not forgotten. The smokers at the gate, the ‘temporary’ classrooms, and the homework, but also the sound and smell of at least 40 mopeds and scooters of all shapes and sizes that transported teenagers from A to B. For those who have no affinity with these motorized wonders, here is an overview of all the choices on the market.

The moped

The Dutch name for moped is ‘bromfiets’, which in comparison to standard Dutch words is actually very simple to understand. A moped is nothing more than a motorized bicycle (fiets) that, thanks to its buzzing 2-stroke engine, makes a ‘brommend’ (buzzing) sound. Typically produced by the brands Tomos or Puch, and in some cases, even equipped with real pedals for when you run out of gasoline. The English word ‘moped’ comes from motorized and pedals, which is another hint at the aforementioned pedal functions old variants used to have.

Puch Maxi S

the ‘snor’ variant is allowed to go 25 kilometers per hour in the bike lane, and the ‘brom’ variant 50 kilometers per hour. In 2022, a general helmet requirement was introduced for both variants, whereas previously the ‘snor’ variants were exempt from wearing helmets.

The scooter

Since the beginning of the century, the moped got a new competitor: the scooter, also known as a “badkuip bromfiets” (bathtub moped). Usually equipped with a 4-stroke engine, these heavier bikes were initially particularly popular among women, as they were much more comfortable and stylish than their ‘manly’ counterparts. Over the past ten years, the scooter has become increasingly popular throughout the Netherlands for its comfort, fuel efficiency, and luxurious appearance.

The ‘schakelbrommer’

This is where the English language stops understanding our Dutch law system regarding mopeds. The ‘schakelbrommer’ literally translates to ‘shiftingmoped’, which is the term we’ll use, but doesn’t officially exist.

Now, the device that it’s all supposed to be about, the shiftingmoped. These machines weren’t intended for your average teenager but rather for the purists, the technicians, and the daredevils. The shiftingmoped essentially resembles a motorcycle with less power; a handy teenager can, in a day’s work, somewhat bridge this power gap and turn it into an almost fully-fledged motorcycle, with a delightful buzzing sound as a result.

These utterly magnificent motorized bicycles, equipped with a 50cc 2-stroke engine powered by precisely two gears and a peak power of 1.66 horsepower, were until the beginning of this century the standard mode of transportation for every high school student who worked enough to somewhat distinguish themselves from the rest. In the Netherlands, since 2005, all mopeds have been equipped with a blue or yellow license plate, also known as a ‘snor’ or ‘brom’ license plate, where

Initially always equipped with an AM6 2-stroke 6-speed gearbox, notorious for its distinctive sound and odor, these mopeds were always the dream for every teenager who truly wanted to stand out from their peers. In the 1960s and 1970s, Kreidlers and Batavia bikes were particularly popular, but in the past two decades, motorcross variants of Derbi and Aprilia have joined the scene, each with their own ‘cool’ appearances, of course.

Kreidler RS

Derbi DRD pro

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Association Of all the motorized means of transportation that someone at the age of sixteen with a valid AM driver’s license is allowed to operate, this is the cream of the crop, the devices that immediately elevated your social status. Even if you weren’t a smoker, you were involved in the gate conversations to catch up on the coolest features, the latest top speed you had reached, and especially how you planned to avoid the notorious WOK status, more about which will be explained later.

Generation-Z

When I drive past my high school nowadays, I encounter a completely different sight than four years ago. The moped has been replaced by exclusively (electric) scooters, electric bikes, sometimes even with a license plate, and worst of all: a massive number of fat bikes.

This trend is not exclusive to my old high school but is instead a broad societal development. Generation Z has swiftly dealt with the traditional transportation hierarchy and decided that mopeds are out of fashion.

Nowadays, they seem to be reserved for an evershrinking group of enthusiasts.

How did this happen? The means of transportation that has been the first step towards independence for every teenager since the 1960s is being rapidly replaced and is now primarily used for delivery services like Thuisbezorgd and Uber Eats. Are they simply out of fashion? Too expensive? Or is there more to it?

Safety

Well, let’s go back to the beginning of this story: officials are calling for license plates and a minimum age requirement for the fatbike to make the streets safer and reduce the number of accidents involving young riders. A noble endeavour, you might say, yet there is a connection to be made here with the decline of moped popularity. The fatbike is a popular means of transportation precisely because, like all electric bikes, it doesn’t require a license plate, driver’s license, or insurance.

Therefore, it is a cheap, easy, and efficient mode of transport, and for young people, it’s a significant improvement over the regular bicycle.

Therefore, it’s plausible that the popularity will rapidly decline if the plans of the Ministry of Infrastructure are implemented, as a driver’s license and insurance would make it much less appealing for young people to start using such a bike. No teenager would ever like to put a helmet on for safety.

What is described above is exactly what happened to the moped world. Before 2005, there was no license plate requirement, and therefore no insurance requirement, for motorized vehicles with 50cc or less. Only in 2006 was the AM driver’s license introduced for this type of vehicle, and in 2023, the helmet requirement for the blue license plates was added as well.

These measures are already quite restrictive, but that’s not all. Periodically, the police hit the streets to stop mopeds and scooters, take them to a roller bench, and check how fast the vehicle can go. If the vehicle exceeds the legal speed, it receives a WOK status (Wacht-opkeuren, which means “Wait-for-inspection”). This implies that you have to have the vehicle re-inspected by the RDW, costing around €70, a considerable amount for someone of adolescent age, and that’s without including the costs of all new parts and repairs that have to be done. This system was devised in 2014 to curb the number of tuned vehicles on the road. Imagine if they were as strict about speed control with cars. The country would be in open revolution.

Of course, as a species, humans naturally strive for increasingly safer situations, and the aforementioned measures do indeed have a positive effect on traffic safety. Nevertheless, it might be good at times to question whether the regulations are proportional to the situation. For instance, in 20162, 44 scooter riders died, which is unfortunate, but considering the fact that we officially still have 1.1 million scooters and mopeds in the Netherlands3, it seems manageable.

The idea is not to convey the notion that ‘everything was better in the past’ or that ‘safety is nonsense,’ but rather to create awareness about the impact of safety measures and their proportionality. Secretly, it’s not a disaster that the polluting moped makes way for the ‘regular’ electric bike, and it’s important to keep the bike path as safe as possible. However, as a lover of combustion technology, it’s still regrettable to see.

I will certainly miss the buzzing sound of a tuned 2-stroke shiftingmoped.

References

[1] Volkskrant - De fatbike is de nieuwe brommer, maar aan opvoeren en scheuren zonder kentekenplaat komt snel een eind [2] Fonds slachtofferhulp- Ongelukken in het verkeer in Nederland | Statistieken [3] CBS - Hoeveel bromfietsen en snorfietsen zijn er in Nederland?

Fatbike (Ouxi V8)

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Education

WINTER BLUES

Navigating Student Wellbeing Through Seasonal Challenges WRITTEN BY ELLE VAN HOUT

Days are getting shorter, the temperature is dropping and winter is coming. All these things are the perfect recipe for the winter blues. During the winter months, the brain gets confused and keeps making melatonin, the hormone that makes you tired, which leads to a tired and worn-out feeling, this is what we call the winter blues or winter dip. Due to irregular hours, late-night studying and socializing students are even more susceptible to a winter dip. Around a fourth of all students experience a winter dip and 10% of students even suffer from seasonal depression.

In order to keep the winter dip at bay we have gathered some tips on what you can do during the winter months.

Go outside

The fresh air and cool breeze will help to stimulate your senses and raise energy levels. Apart from the increase in energy, going outside also helps feeling generally less anxious and stressed.

As much as spending 15 minutes outside can already improve health and well-being significantly. So put down your phone, close your laptop and take a walk.

Light therapy

Due to the reduced UV exposure during winter, the body produces less vitamin D. A vitamin D deficiency can affect your circadian rhythm, this disturbance can negatively affect your quality of sleep resulting in low energy levels. The earth is tilted away from the sun during the winter, so to fix this going outside is not enough. Light therapy might be a solution. With light therapy, people sit in front of a special lamp that provides exposure to 10.000 lux (lumen per square meter) of light. The best results of light therapy are obtained when it is used for about 20 minutes right after waking up, this can help reduce feelings of tiredness and lift your mood.

Enjoy the typical winter cuisine

We all know the typical winter dishes, like stamppot, goulash and meats like beef and lamb, are super tasty, but they can actually also help to make you feel better. These foods contain more iron than the regular food consumed during the spring and summer. Iron is needed in your body to help absorb oxygen in your red blood cells. This is why it’s important to eat around 9 milligrams of iron per day for men and almost 15 milligrams a day for women. This can help you with temperature regulation and to feel more energized.

Exercise

The student psychologist can give you advice and then refer you to the appropriate help within or outside the university. student.psychologists@tue.nl

Although, exercising might not be on your mind when feeling down it is important to get moving. A quick run or bike ride can really boost your mood. Exercising helps to release endorphins, which is the hormone that makes you feel happy and reduces pain. If you don’t want to exercise alone, try to go with some friends or to the Student Sport Center where they offer group lessons daily. Naturally, all these things might still not help and you are in need of more support. We have compiled some contact information if you want to reach out to any instances that the university provides. Remember it’s ok to ask for help and you are never alone.

Confidential advisors

Lighthouse

Contacts Student psychologist

The student psychologist can give you advice and then refer you to the appropriate help within or outside the university.

Henny van Alphen (f) h.a.m.v.alphen@tue.nl Hjalmar Mulders (m) h.c.j.mulders@tue.nl

For struggles with your study due to any circumstances, Lighthouse offers a wide support platform. For more information contact: lighthouse@tue.nl

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Education

CAMPUS ART The university does a lot to make you feel welcome on campus. There are many places to eat food, study and just generally hang out. An often overlooked aspect of the decorations on campus is all the artwork that can be found here. In this series of articles, I want to find out what people think of the abstract art that the campus provides, but in a mechanical engineering way. I have asked mechanical engineers to grade these artworks based on some core CBL values to evaluate every piece of art. These values are efficiency (how clear is the interpretation of the artwork), craftmanship (how nice it looks), and creativity (how original is the artwork).

WRITTEN BY JASPER BEKKERS

Ring van Möbius Ring van Möbius is a large sculpture of metal and concrete that stands near one of the entrances of the TU/e made by Hans Kalkhoven. It is based on the famous eponymous mathematical object, the Möbius strip, that describes an object where you, when following the path, end up in the same position in space and time, but on a different side of the object. The rocks on which the sculpture is placed come from specific quarries in Germany and Norway. You might remember this object when it was used to explain time travel in Marvel Endgame.

Efficiency: Craftmanship: Creativity:

“Sometimes you are in the hole and sometimes you are not. Sounds like life.” - Jesus Vliegend Vliegend (Flying) is a bronze sculpture made by the expressionist sculptor Wessel Couzijn placed in front of Matrix, overviewing the pond. Like many expressionist artworks, it is hard to decipher what it actually means. During his lifetime, Wessel was always hired for projects so there is no common theme between his works, except for the sharp bronze edges and odd shapes. This particular one, though, looks like it has been pierced through its hull. Maybe it resembles a shot-down airplane that has made an emergency landing, now pointing to the sky in which it once flew.

Efficiency: Craftmanship: Creativity:

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“Shipwreck, because studying makes you one.” - Albert

Education

De (technische) student De technische student (the technical student) is a life-sized steel sculpture that greets you at the main entrance of Atlas. Built by Oswald Wenckebach and placed in 1958, it is one of the oldest artworks on campus. Through these years it has stayed young and has seen the campus change around them but still guarding the main building. One could wonder what this student has been studying for all this time, but considering they haven’t gotten their degree in 70 years, they’re probably a mechanical engineer.

Efficiency: Craftmanship: Creativity:

“He is definitely judging someone pretty hard” - Anonymous Vloerreliëfs Vloerreliëfs (floorrelief) is a large interactive artwork between vertigo and matrix. This work has also been on campus since the start and has seen to progress of the surrounding area. At the start, this work fit in with the concrete wasteland of our campus, but throughout the years the campus has grown greener and greener, showing the natural progression of nature. Like From Bar To Couch, this artwork is known more for its congregation potential than its aesthetical purpose, but one can still wonder if this relief is made to be as uncomfortable to sit on as possible.

Efficiency: Craftmanship: Creativity:

“Parody of the Colloseum” - My name is Carlo Franceschi,, commander of

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Education

Seed nr. 4

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st r ye ating t

Seed nr. 4 is a brass sculpture seen by many but understood by few.

It was made by the sculptor Shinkichi Tajiri, who had a long history of war and discrimination. Part of a group of Japanese who lived in America during the Pearl Harbor attack, he volunteered to join the Allied army. After being injured, he pursued a life as an artist. With this line of artwork called “Seed” he wants to convey a feeling of growth and life. With this particular work, he has tried to combine both male and female parts that combine to create life. This is one of the only works on campus where your first thought is probably the correct one.

Efficiency: Craftmanship: Creativity:

“Potato on a stick” - Anonymous

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Tech

GO SHARING VERSUS TIER TEST TRACK: ELECTRIC SHARING BIKES WRITTEN BY BEN GORTEMAKER & TOM SLANGEN

It has been four years since shared electric scooters have been introduced into Eindhoven.

Since that time a lot of things have changed, Felyx scooters are no longer on the road and have been replaced by Check. Most notably since September 2021 shared electric bikes were introduced into Eindhoven. Two brands of bikes were introduced: Go Sharing and Tier. The advantage of these electric bikes is that you don’t need a driver’s licence to legally drive them. In this article, we will review these bikes and look at which one is better.

Performance

To start let’s compare the performance of both electric bikes. Theoretically, the range of the bikes is unlimited, however, at some point the battery will run out and the power assist will stop. This is very unfortunate as the main reason that you got the shared electric bike is for the power assist. Next to the range, the top speed is another important aspect we will measure.

Go Sharing

Tier

The top speed that we managed to get with the Go Sharing bike took a lot of effort and resulted in going 25 km/h. But with a more comfortable amount of effort, the top speed was 21 km/h. The range of the Go Sharing bikes is 54 kilometers, plenty enough if you want to go anywhere here in Eindhoven or the region.

The bike from Tier went a lot faster than Go Sharing, the acceleration was higher, and the top speed was 25 km/h without it taking a lot of effort. However, this does come with a lower total range of 45 kilometers. Which is enough to go from Eindhoven to Someren and back in under two hours. Taking the tier bike for a 45-kilometer ride instead of the Go Sharing bike would save you over 20 minutes, or a real wet back.

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Tech Ergonomics

The next thing we will investigate is how comfortable the bikes ride and what kind of functionality they have. What kind of unique things can they do and what can one do and the other not? Or which implementation of the functionality is better.

Go Sharing

Tier

One immediately obvious feature that the Go Sharing bike has and the Tier does not is the basket on the front of the bike. It is relatively small and for example, a beer crate cannot be put into the basket. Both bikes don’t have a back bracket, meaning that it is impossible or very uncomfortable to carry a friend on the back of your bike. But in general, it is slightly better than the Tier bike but not very great. The next big point is the comfort of the ride, and in the case of the Go Sharing bike, this is terrible.

One could feel every bump in the road and the bikes shake so much it could hurt after a longer trip. Next to that the bike is also difficult to adjust and we would not trust the phone holder with said shaking.

Riding the Tier bike next to being effortless pedalling, also did not shake around very much. Riding it was almost as comfortable as riding a scooter, with the only difference being that the speed is controlled using your legs. The height of the seat is also easy to adjust making it easy to get just right, and making the Tier bike much more ergonomic. However, locking and unlocking the bike takes a bit more effort as a weird locking pin has to be inserted. Lastly, the phone holder is well integrated into the frame of the bike and works very well. It is a lot better than the Go Sharing bike where it felt like an afterthought.

Price

Parking

An important aspect of these bikes is of course the price. If these bikes are very expensive, they will not be used. It is possible to park the bike somewhere, with a fee that is lower than the hiring price. This is also available outside the designated parking areas.

Go Sharing The base price of a Go sharing e-bike is 50 cents. After this, the bike costs 26 cents per minute. It is possible to buy certain packages to get a discount. The first package costs 9,99 euro and you get a 0 percent discount. The second package is 19,99 euros with a 2 percent discount. The third package is 49,99 euros with a 7 percent discount. The last package is 99,99 euros with a 17 percent discount.

Tier For the Tier bike, the base price is 1 euro. However, the price per minute is 23 cents. At Tier bikes there are also some different packages which can be bought. The first package is 12,99 a day which gives unlimited unlocks and 60 minutes of riding time.

Then there is a package of 4,99 per month for unlimited unlocks of the bikes. The last package is 29,99 for 30 days and it gives unlimited unlocks and 200 minutes of riding.

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Go Sharing The parking spots for Go Sharing are somewhat more limited.

Not every part of Eindhoven is available for bike parking. The available spots may contain small sections where bikes cannot be parked. In the city centre, it is also prohibited to park bikes. In the east, finding a parking spot for the bike is almost impossible.

Tier

Tier bikes have a much larger range than Go Sharing bikes.

Additionally, in the permitted areas, there are almost no small spaces where you cannot park the bike. In the city centre, bike parking is not allowed. However, the east of Eindhoven is available for bike parking.

Tech Conclusion The Tier electric sharing bike is better in almost every way compared to the GO Sharing Bikes. The only downsides are that it is slightly more expensive, it has no basket on the steering bars and the range slightly less. If you can spare the money, don’t need to go far away from Eindhoven, and don’t need a small basket for your groceries you are better off with a Tier bike. With which you can enjoy a more comfortable and faster ride, better parking places and all in all an overall better experience. We think that in most cases the better riding experience outweighs de discomfort of the GO Sharing bike and therefore recommend using the Tier.

Whereas in de case of the Tier, you can just download the app and hop on. In this case, it comes down to your personal preference, do you want to save time, have a driver’s license, want more comfort, and pay the price then use a sharing scooter? But in all other cases, it is best to use the Tier electric bike.

Comparing the Tier bike to the scooter review done in 2021 it is clear that the scooter provides even more riding comfort and speed. However, this does come at a higher price point and one needs a driver’s license to be able to legally drive these scooters.

Specifications Top speed Action radius Base driving costs

GO Sharing

Tier

21 km/h

25 km/h

54 km

45 km

26 cent per minute + 50 cent unlock

29 cent per minute + 1 euro unlock

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Career

Cooling of Thales’ Radar Systems WRITTEN BY JESPER VELDHUIS

I am Jesper Veldhuis, 24 years old, and I live close to Hengelo, where the headquarters of Thales NL is located. I did the graduation assignment for my MSc Mechanical Engineering (University of Twente) at the hardware engineering department of the company.

Afterwards, I got hired at the environmental competence center (ECC) as a mechanical/environmental engineer.

At this department, we provide support for the hardware engineers in the form of analyses and practical tests. In the end, we have to qualify the systems with respect to environmental conditions such as temperature and vibrations, but also with respect to induced conditions, such as shocks from underwater explosions. In order to do this, we have all kinds of systems at our disposal. Varying from a large climate chamber to shock and vibration tables.

The challenge

When looking at naval ships, you often only get to see the radars themselves. However, there are also a lot of subsystems behind them. Examples of this on the hardware side are the power supply and processing cabinets, which provide a radar with the required power and process large amounts of data. These cabinets have large amounts of heat dissipation that needs to be removed, but they also have to be able to withstand shock, which means their structural integrity is of importance. These are some typical challenges that a hardware engineer at Thales has to solve.

HNLMS De Zeven Provinciën (F802)

The cooler

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A project that I participated in was the development of a cabinet side cooler. This is a new type of cooler that is to be attached to the side of the payload cabinets to extract their dissipated heat. The heat is to be removed by airflow to ensure that the components in the payload cabinet remain reachable, thus improving its maintainability.

The heat is subsequently transferred to the ship’s cooling circuit, meaning that an air-to-water heat exchanger is required. Due to the stringent requirements on the dimensions of the side cooler, the heat exchanger had to be dimensioned by myself. This enabled us to find the optimal design in terms of cooling power, dimensions, and weight. The design also had to be shock proof, meaning that it was placed on spring elements, reducing the initial acceleration that the cabinet would experience. However, it would still have to endure the dampened shock, as a result of which the structural integrity of the design was still of importance.

A shock pulse has a certain Concept Design frequency, the natural frequency of the side cooler on spring elements therefore has to be far enough away from the pulse frequency to ensure that an incoming shock is not amplified. Subsequently, the natural frequency of the structure itself had to be far enough away from both of the above, meaning that it had to reach a minimum stiffness. Several smart solutions were implemented to increase the cabinet’s stiffness, without adding much weight.

Career Additional challenges were the reliability and maintainability of the design. For reliability, it was important that the amount of components was kept at its minimum and that there was no single point of failure. The latter meant, that for example an additional power supply unit was added, such that the blowers could continue operation in the case the first unit failed. For maintainability, it was important that all electrical components were located at the front, such that they could be reached by a mechanic after the cabinets were installed on-board.

enough airflow at these resistances. The second goal of the thermal analysis was to check whether the temperatures in the payload cabinets would stay below certain limits when the heat dissipation was at its maximum. The goal of the modal analysis was to find the first natural frequency of the concept design, which would give a good indication of whether its structurall stiffness would be high enough.

Finally, a concept design of the cabinet side cooler was proposed osed that would integrate the subjects of thermal and shock, hock ock, and in addition, put focus on reliability and maintainability. The design solves the most important challenges and satisfies the requirements.

Modal Analysis (in Ansys) After an initial concept design was created, an analysis could be performed to check its cooling performance and structural integrity. This was done by performing both a thermal analysis in FloTherm and a modal analysis in Ansys. The first goal of the thermal analysis was to find the pressure resistance of the different side cooler and payload cabinet combinations, such that a type of blower could be selected that could provide

Thermal Analysis (in FloTherm)

Thales at TU/e Thales is one of the main high-tech companies in the Netherlands, known most famously for its pinpoint accurate radar systems. Thales works on cutting-edge technology for the defense industry, but also space systems, cyber security and communication systems.

Mart de Bruijn

Campus Brand Ambassador @ Thales mart@thalesoncampus.nl www.werkenbijthales.nl

Thales has several locations throughout the Netherlands, and for employees, there are a lot of international opportunities as well. We are always looking for new talent to work together on innovative projects and technologies.

Thales is always flexible in setting up graduation projects and internships to your and Thales’ interests. If you would like to come in touch to see what the possibilities are for you, you can reach out to me, your Campus Brand Ambassador.

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CULTURAL DIFFERENCES WRITTEN BY JASPER BEKKERS

The Netherlands is a popular country for people studying all over the world and since the switch to an English campus, the TU/e is getting a bigger and bigger community of internationals. In 2021, 19% of all students were international, which has grown bigger since. This leads to the intermingling of a lot of cultures. Dutch students, however, still dominate the campus and their ways of living causes many international students to be concerned. In this article, I will be exploring the experiences of first-year international students and their introduction to Dutch cultures and how Dutch students experienced teaching the international the way of the adtje.

The international experience

From the sample taken, 55% of the students were international. This is probably due to a higher participation rate of internationals in the introweek, while Dutch people might enjoy their once-a-year 30-degree beach day. In the intro groups, most people had about 5-6 Dutch people in their group, which is enough for the others to learn all about the student life. Most people definitely got the memo and have a good feeling about the culture of cheese and beer.

Internationals were eager to join the evening events, 60% even went to all of them. This is also where the surprises came in. By far most people were surprised about the ginormous amounts of alcohol that was consumed (and also how early in the day). Combined with early parties, tikkies and stolen bikes, the students at the introweek were able to experience most of what Dutch student culture has to offer.

Then there was the big challenge: doorhaaldonderdag.

A tradition among students of the tu/e, doorhaaldonderdag is the ultimate experience of study life. Long club nights, excessive drinking, and big hangovers. 38.5% were able to complete their introduction week with a blurry night and some regrettable life decisions.

Then, the most defining aspect of any country’s culture: The food. The Dutch are not known for

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their great food, but we do excel at one thing: Fried and greasy snacks. And that shows from what the internationals experienced. Most people would say that the kapsalon (which is indeed Dutch) is the best food, closely followed by bar snacks like bitterballen, fries and kaassouffle.

Association

The Dutch perspective

The people of the Netherlands can often be seen as stubborn and direct. But if there is one thing they enjoy, it is sharing their habits and language.

Most were happy with it, but some might have thought the drinking was overrepresented in the introduction week.

The Brabanders were very keen on sharing their gezelligheid and local songs, and most people loved going out and showing Stratum to the internationals.

Adtjes and shotguns were also done all around; however not as intrinsically Dutch as we like to think. The recipe of the boterham was also shared with the lucky students of the introweek.

Dutch advice to the internationals “it’s not all about getting drunk and party, it also doing things together and sharing your hobby’s .”

“Dutch people are a little strange, but really fun”

“Boterhammen zijn goed spul” (Sandwiches are good stuff)

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Tech T Te ech ch

WATCHES: PRECISION TIMEKEEPERS WRITTEN BY DANIËL KLEINJAN

It has existed for a considerable duration, helping us keep track of time the fashionable way instead of using our mobile phone; it’s the watch. For some, it is considered to be a fashion statement whereas for others it is used as an investment to make some money.

For me as a mechanical engineer, it’s also the technique of how such a small product is able to accurately display time. Two of the most prominent types of wrist watches are the mechanical watches and the quartz watches, which will be discussed in detail in this article.

Mechanical watches

The first type of watch is one which probably will be most interesting to us as mechanical engineers; it’s the mechanical watch, which does not contain any electrical components. The part of the watch that produces the time is called a movement.

Within the movement, the key components are located, each with its own distinct function.

Main spring

First of all, an energy source is required. For a mechanical watch, this is the main spring. This spiral-shaped torsion spring is located in the main spring barrel and needs to be wound in order for it to release energy to power the movement. This can be done in two ways, either by manually winding the crown or through a rotor that moves due to gravity, resulting from movements of the user’s arm. A movement with this type of selfwinding function has the nickname ‘automatic movement’ and is widely used in most mechanical watches these days. The motion resulting from these winding methods is translated to wind the main spring via the winding pinion, a gear that is connected to

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the inner part of the main spring. This gear can only rotate in one direction, as the energy needs to be stored and not released immediately. Often the term ‘energy reserve’ of a mechanical watch is mentioned, which says something about the amount of time the watch can function without being wound or worn.

It also tells something about the efficiency of the watch both in terms of how much energy can be stored in the main spring as well as how efficiently that energy is being used to power the movement.

Exploded view of the main spring barrel with an unwound main spring and winding pinion in the middle.

Tech

The gear train connects the main spring on the right with the escapement wheel on the left. Through the gear train, energy is translated to the motion works that power the minute and hour hands.

Gear train

When the main spring is fully wound, it can release energy via the outer part of the main spring barrel, which has teeth on its outside through which the energy is transferred to the gear train. On the other end, the escapement wheel is located, which combines the energy with controlled oscillations from the balance wheel, which will be addressed in a few moments. From the escape wheel, another part of the gear train transfers this energy to gears that control the minute and hour hands. These gears are called the motion works and are coupled through different gear ratios as they need to move at different speeds to correctly display time.

Balance wheel and escapement

The escapement consisting of the escape wheel and the pallet fork, which is connected to the balance wheel what is controlled by the hairspring.

But how is the movement able to provide an accurate time representation? This occurs within the balance wheel and escapement, which essentially form the heart of the movement.

The escapement consists of the pallet fork and the escape wheel.

As elaborated, the escape wheel is connected to the mainspring barrel via the gear train, which makes it experience a force to rotate. However, this is prevented by the pallet fork. Due to the shape of the escape wheel’s teeth and this force, the pallet fork can be pushed into two positions. However, on the other side of the pallet fork, this motion is regulated by the balance wheel.

Within the balance wheel, the hairspring is connected. This torsional spring with a thickness smaller than a human hair can be wound and unwound multiple times per second, allowing the balance wheel to oscillate like a pendulum in a wall clock in a very precise manner and ultimately control the pallet fork.

Between the time the pallet fork moves between these positions, the tensioned escape wheel is allowed to move for a moment. The ticking sound is the familiar sound produced by a mechanical watch and is the pallet fork that clicks in and out of the escape wheel. Every click is called a beat and the usual beat rate is

about six times a second, or 21,600 times an hour. For every beat, energy is released through the escape wheel to the part of the gear train that is connected to the motion works. Since six beats per second are produced, the second hand moves six times a second, resulting in a smoother motion than just once a second.

Crown

Recently, winter time started, which means people with a watch need to reset their time. This is done by making use of the crown of the watch, which is for most watches located in the 3 o’clock position. The crown is a rotating wheel on the outside, but on its inside it has a squared part which is initially free to rotate and is not connected to anything.

However, the crown can be pulled out into two or three positions, that internally allign it with a gear. The first gear is connected to the canon pinion. This small part can used to move the minute and hour hands while the gears powered by the escape wheel can still rotate. Additionally, in watches with a date function, there is an extra position to set the correct date separately from time.

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Tech The next position in which the crown can be set is to control the winding pinion, where rotations of the user are translated into a rotation to wind the main spring.

The main spring can only be wound in one direction so rotation in the other direction is prevented by the click spring, a small spring that clicks back for every small rotational motion of the crown.

Support structure

The final component of the movement is the support structure, which holds every component securely in place. The base part is called the main plate and is on the top side of the movement. Connected from below is the barrel bridge, which holds the mainspring barrel.

The train wheel bridge holds to gear train. Finally, the escapement and balance wheel are connected to the main plate via the pallet bridge and balance bridge. On the side of the main plate that faces up, the dial of the watch can be placed.

Jewels

Support structure (upside down view) that holds every component.

To keep a movement in a fine condition, friction at any location needs to be prevented, as this causes wear, which can eventually lead to a drop in timekeeping accuracy, energy efficiency and eventually a decreased lifetime of a watch. At for example pivot points, where gears are held in place, ‘jewels’ are located. These jewels are made out of synthetic ruby or sapphire, which are more wear resistant and smoother and help to ensure the long term quality of a watch. At the pallet fork, two jewels are placed as well, as clicking in and out of the escapement produces much friction. The jewels can be seen in the visualizations in red ruby coloured. A movement is considered to be fully jewelled when at least 17 jewels are placed at the most vital locations in a movement.

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Complications

Some mechanical watches feature extra functions beyond just telling the time. These types of functions are referred to as complications. One of the most common complications is the date function, where one or two digits represent the current day of the month. Usually, this is done through a disk that moves once a day (later at night). However, this means that in months with only 30 days, the crown needs to be used to skip a day. A more sophisticated date complication is the perpetual calendar, which is able to correct for the number of days in every month, including February and even leap years. Other types of complications include the moon phase, which displays when the moon is at its full, half, quarter or new phase. For people who travel a lot, the dual time complication is a great addition, as it contains an extra hour hand, which gives it the ability to display two time zones at the same time.

Internal look in a mechanical movement. The hairspring and balance wheel are showed in the left. Around the watch, several light purple colored jewels are located.

Tech

Watch from Patek Philippe with the moonphase complication at the 6 hour position.

Quartz Watches

The mechanical watch is very popular as it does not have any electrical components. However, they present a disadvantage in terms of accuracy, as even the most expensive and high quality mechanical watches from Rolex or Patek Philippe lose seconds a day. For people to whom seconds matter, the quartz movement is very interesting. The first watch with a quartz movement was introduced in 1969 by Seiko, a Japanese watchmaker brand that is considered to be one of the best outside the famous Swissbased watchmakers like Rolex or Audemars Piguet.

Rolex watch with the dual time complication.

movement is more accurate than a mechanical watch has to do with this high frequency, which is a couple orders of magnitude larger than the oscillations of the hair spring in the mechanical watch. Due to this, the integrated circuit can count more accurately, resulting in a better time representation. Moreover, the mechanical properties of a quartz crystal allow it to be pretty accurate over temperature variations, increasing the stability of the timekeeping. There are watches that combine the quartz

A quartz movement is powered by a battery that gives small electrical charges through an integrated circuit to a quartz crystal, shaped like a tuning fork. For us as mechanical engineers, the resulting mechanism from these electrical charges could sound familiar; it’s the piezo-electric effect, or actually, the reversed piezo effect. When a quartz crystal gets an electrical charge, it is transferred into mechanical energy, in the form of an oscillation. By tuning the shape of the crystal, it will vibrate with a frequency of 32,768 Hz and pass this on to the integrated circuit. Through this integrated circuit, the signal is transferred as a one second signal to a small electric motor, which powers the gears and the hands of the movement.

The reason why the frequency of the quartz crystal should exactly match 32,768 Hz is related to the fact Inside of a quartz movement showing the integrated circuit. that it is a power of two, which means an electrical divider is able to divide it fifteen times until a 1 Hz signal, which technique with a battery but have an addition; energy can be can be transferred to the motor that powers the mechanical produced and stored in the battery. A company that exploits this part of the watch. In addition, the essential reason why a quartz feature is Seiko, which uses an internal electrical rotor (also seen in mechanical watches) and stores the generated kinetic energy in the battery. My daily watch at this moment is such a watch, from the Seiko Kinetic line-up. Within Seiko, another way of generating energy is through light, which is done in their Solar line-up of watches. The advantage of these types of watches is that energy can be generated, such that the watch will have a much longer lifetime since the battery needs to be replaced less often than general quartz watches.

Quartz crystal shaped like a tuning fork.

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Association

Hephtig: Student Protests Anyone with even a remote idea of the happenings at the TU/e, will not have missed the efforts of the University Rebellion to bring their agenda to the attention of everyone on campus. Inspired by their protests, I decided to take a look at the rebellious history of Dutch students during the late sixties when students all over the Netherlands protested in pursuit of governance reform at their universities.

WRITTEN BY CAS DIJKSTRA

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Association

The introduction of student grants meant that during the fifties and sixties, studying at a university became available to an ever greater number of people, who previously would not have been able to afford it. It was during these years that in many student cities throughout Europe, students started questioning the role of the university in society.

They wanted more democratic governance of the institutions and a focus on societal issues as well as academic ones.

At the time, the governance of a university was in the hands of two bodies: the Board of Trustees (NL: College van Curatoren) and the Senate. The Board of Trustees consisted of prominent figures from industry and politics (comparable to the current Supervisory Board), whereas the Senate consisted of all professors and was under the leadership of the Rector Magnificus. However, during the sixties and seventies, young people started questioning many of the traditional hierarchical norms, values, and governance structures in society.

This combined with the significant growth in the student population was a recipe for revolt…

1968: Nijmegen

Nowhere in the Netherlands was the influx of new students seen as strongly as at the Catholic University of Nijmegen. In the fall of 1968, the Dutch government was working on reform of higher academic education. The students in Nijmegen saw this as an attempt to make the education system work for capitalistic and imperialistic ideals and decided it was time for action. The activists turned the auditorium into a “discussion center” in the first-ever occupation of a university building in the Netherlands.

During the next years, unrest grew in the Netherlands surrounding the governance of universities as students continued their plea for their right to have a say in the way universities shaped their policy. After the responsible minister

First occupation of a university building in Nijmegen

introduced a governance reform that would ensure students received a say in the general management of the universities, you would think, the unrest would be resolved. However, the students in Nijmegen still did not feel heard enough through these new rules. On top of that, the professors of the university now felt like the Rector Magnificus did not listen to them enough too. This eventually led to the Rector getting caught between two opposing interests. Unable to satisfy anyone, he eventually became the first Rector Magnificus in Dutch history to resign under student pressure.

1969: Amsterdam

Although it was the first, the occupation of the auditorium in Nijmegen would not be the largest student-occupation in the Netherlands that year. The desire of students to obtain a say in the governance of the university was not unique to Nijmegen and students were protesting throughout the Netherlands. The occupation of the Maagdenhuis in Amsterdam may be the most famous of these actions.

In May of 1969, hundreds of students entered and subsequently refused to leave the Maagdenhuis in Amsterdam. The students obtained letters and minutes from the University Board that painted a picture of a Rector Magnificus who did not appear very enthusiastic about the idea of governance reform. By this time the police had arrived and decided to cut off the occupying students in the hope that they would eventually give up and go home. However, the students created airlifts to the neighbouring buildings to provide the occupants with supplies and bring the information that was found inside to the outside.

Despite their obstinance, the students were quite well-organized. Committees were formed with responsibilities for cooking, cleaning, and

Student occupation of the Maagdenhuis

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Association keeping order. The library was an important point of access for the students to bring in supplies and the professor who held responsibility for this building was successfully able to negotiate with the organizers to ensure the safe-keeping of valuable books and documents in the library by the occupying students. In the end, the well-organized protest meant that despite the efforts of the police to cut the students off from supplies, the occupation lasted for five days. After this, the police had to raid the building, removing the occupants by force.

1969: Eindhoven

Of course, it would be remiss not to mention the efforts of the students in Eindhoven pushing for governance reform. In April of 1969, the Board of the University of Applied Sciences (NL: Hogeschool) in Tilburg, closed the institute after students revolted by occupying the senate hall and proclaiming the catholic institute would now be called the “Karl-Marx University of Applied Sciences”. In Eindhoven, the ESM (a sort of Umbrella Association representing all student associations) called an assembly of students and employees to the Senaatszaal to discuss the Tilburg revolts. During an hours-long discussion, those present expressed their solidarity with the students in Tilburg. The decision of the Board in Tilburg to close the institute is condemned and teachers from the THE (Technische Hogeschool Eindhoven; Before becoming a university, the TU/e was considered a University of Applied Sciences) are encouraged to aid the students from Tilburg in any way they can.

A week later, however, a second assembly is called. This time the point of discussion is not the situation in Tilburg, but the governance culture at their own THE. A massive assembly of 800 students and staff comes together to discuss their participation and voice in the running of the institute. In a vote per acclimation, a motion is accepted that proposes the creation of “THE-council” in which all stakeholders of the THE are represented. A few days later, in the same week the police raids the Maagdenhuis in Amsterdam, the Board of Trustees announces it will indeed be creating such a council to democratize the governance of the THE, becoming the first of its kind in the Netherlands.

It appears, however, that some students were still left somewhat unsatisfied. In October of 1969, during a meeting of the Board of Trustees, several students invaded the meeting and refused to

Occupation of the trustees meeting at the THE leave, stating that these meetings should be publicly accessible to everyone. The trustees are furious and demand the students to leave who kindly refuse this request. In the end, the occupation did not last long as they were removed by force. Surprisingly this was executed not by the campus security or police, but by other students who (apparently quite severely) disagreed with the occupation.

Governance reform

In the end, the protests all around the Netherlands in the late sixties and early seventies had long-lasting effects on the way universities are run. After the period of unrest, new federal legislation was introduced in the early seventies, abolishing the Board of Trustees and Senate and introducing in its place: the University Board (College van Bestuur) in which the Rector Magnificus would take place and the University Council in which students and employees are represented. This reform solidified the voice of the student population in the governance of these institutes of education and research and led to a greater consideration of societal issues in the governance and priorities of the universities.

For anyone interested in more stories of student protests at the TU/e or just looking for a great SOG, I highly recommend checking out the TU/encyclopedia article on this and other topics. (Did you know that the creation of the old Bunker was the result of a student protest in 1964?)

Students exchanging information and supplies between the Maagdenhuis and the adjacent library

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Association

TEST YOUR ME-LEVEL

WRITTEN BY STEFAN GEERTS

Many people proudly identify as Mechanical Engineers, and some even attain distinctive titles to commemorate this significant accomplishment. Nevertheless, the attainment of the title of Mechanical Engineer typically only involves the completion of theoretical examinations created by individuals who established themselves as Mechanical Engineers many years ago. How much of a Mechanical Engineer are you really? That is what you will find out with the test below!

Bike fixing

10%

Have you ever fixed your bike?

Yes

No

Ambitious project

20%

Have you ever started a too ambitious crafting project?

No

All the time

Yes

π

Work pants

What is the value of π

Do you own special work pants?

3.1415926535897

Yes

3

932

3846…

30%

No

40%

Software Marc Mentat, Siemens NX or Matlab?

Marc Mentat

NX

Baco What is a Baco?

Tool

Drink

Matlab

Dommel

g

What is the Dommel for you?

What is g?

River

Blood

10

Tape + WD40

Bike fixing

Do you have ducttape and WD40 at home?

Has someone else asked you to fix their bike?

Only 1

No

Many times

Lots

Screwdriver Philips

70%

How many cylinders do you have at home?

Torx

5-10

11+

Tools

Welding Have you welded before?

€500+

60%

No

How much are your tools worth? €0-500

9.81

Cylinders

Philips, Flat, Torx Flat

50%

Yes

0-4

No

CONGRATULATIONS! Congratulations on successfully completing the Mechanical Engineer Identity Test! You’ve navigated through the challenges and questions with precision and expertise. Your results demonstrate your true understanding of what it means to be 100% Mechanical Engineer.

80% 90% 100% 52

Association

HISTORY OF THE COBO

WRITTEN BY TOM SLANGEN

As the evening progresses, the atmosphere at The Weeghconst becomes livelier. Laughter and chatter fill the air, blending with the clinking of glasses and the occasional cheers from the jubilant crowd. The new Board of W.S.V Simon Stevin, having rung the bell and initiated the free drinks, mingles with wellwishers and fellow Association members.

The tradition of recipiëren continues, with Boards from various student and study associations making their way to the Pedel. Each group, with a unique flair and camaraderie, lines up to express their congratulations and exchange pleasantries with the newly elected Board. The exchange of gifts and the shared shots create a sense of unity among the diverse associations present.

Meanwhile, the order before the podium proves effective in preventing any attempts at brassing.

Members of different associations adhere to the rules, ensuring a respectful and enjoyable evening for everyone. The orde, standing guard, adds a touch of order to the festivities, creating a balance between celebration and maintaining the integrity of The Weeghconst.

As the night unfolds, the guest book fills with heartfelt messages from attendees, expressing not only good luck but also gratitude for the shared moments and memories within the Association. The pages become a chronicle of camaraderie, reflecting the tight-knit community that W.S.V Simon Stevin fosters.

Amid the celebration, someone suggests a toast to the rich history of the constitution drink, acknowledging its roots in Gemini and the journey it has taken to Traverse. The mention of Gemini sparks nostalgic conversations among the older members, reminiscing about the early days and the unique charm that Gemini brought to the tradition.

As the clock ticks, the festivities show no signs of slowing down. The music grows louder, and the floor beckons as Association members, old and new, come together to celebrate the vibrant spirit of W.S.V Simon Stevin. The constitution drink, a cherished tradition, continues to weave stories and memories, connecting generations of members in a tapestry of shared experiences.

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Association

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Association

Numbrix The goal is to fill the grid with a series of consecutive numbers from 1 to 225. Consecutive numbers must be placed adjacent to each other either vertically or horizontally (but not diagonally).

MADE BY STEFAN GEERTS

36

2

38 35

28 42

16

46

3 22

98

4

20

53

60

52 85

94

75

104

66

82 107 130

160

80 79 78

112

70 155

144

158

135

126

149

170

142 122 1515 medium 10 198 202 201 204

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181

176

194

184 192

190

186 221 224 222

Please provide your feedback to this openME via the 5 questions in the QR-code!

Association

STERRENHOEKJES •

Jens S: “Bij intermate kreeg je vroeger ECTS voor commissies.” Ilias: “Daar leer je ook meer van dan hun hele onderwijsrooster”

•

Glenn op Tinder: “Oeh ze heeft wel een Green Egg. Dat is wel bonus.”

•

Tom: “Aboe ....., terroristenleider van vroeger, hmmm volgens mij is dat Aboe Teleb” Floris: “Gast dat is de burgemeester van Rotterdam”

•

Stijn: “Het is echt onhandig om alleen je ballen uit je broek te hangen”

•

Bregje: “Kijk Elise, iedereen vindt mijn doos beter”

•

Katty over lamellen: “gordijnen maar dan in plakjes”

•

Ilias: “Ligt die laatste lullo hier?” Elle: “Wie? Van Kemenade?”

•

Ruben: “dus wat doe je naast Hoofdredacteur zijn?”

Stefan: “uhhh... bier drinken”

•

*roestvast staal staat in de puzzel* sjaars: “o dat zou rvs kunnen zijn” Eline: “oooooooo daar staat rvs voor”

•

Marne: “Mijn vingers mogen alles”

•

Belgen zijn dom. Lloyd: “Nee wij scoren beter als jullie op de spellingstest”

•

Mathijs tijdens brouwerijtour: “Wat is jouw favoriete Lager? Kogellager”

•

Ben: “Sorry voor je borsten.”

Top posters of 2023 1. Kim Smulders (72 ‘vo) 2. Sebastiaan Jansdam (72 ‘vo) 3. Jens Swarts (57 ‘vo)

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Association

CONTEST TIME Submit your answer and win a pair of Samsung Galaxy Buds 2!

Contest 54.2

Contest 55.1

The previous prize question was proven to be quite difficult.

In a world, far from now (but maybe not as far as we think), there is a first-year CBL course with 67 groups. Every group is tutored by a tutor, ranging from 2nd-year bachelor students to 4th-year master students.

The solution is as follows; In the worst-case scenario, 17 times.

Simon denotes the kegs K1-K10, He then tests the following nine pairs: (K1,K2), (K1,K3), (K1,K4), (K1,K5), (K1,K6), (K1,K7), (K1,K8), (K1,K9), (K1,K10) Case 1: One of the tests results in a red light: This means that K1 contains acid. Furthermore, the light turned green at least twice, meaning that those two kegs (Ki, Kj) can be chosen, meaning that the search can be terminated in 9 tests or less.

Case 2: All of the nine tests result in a green light: This means that K1 contains beer as K2-K10 can’t all contain beer. Now Simon tests 8 more pairs: (K2,K3), (K2,K4), (K2,K5), (K2,K6), (K2,K7), (K2,K8), (K2,K9), (K2,K10).

2a:

2b:

One of the tests results in a red light: This means that K2 contains acid, and so Simon can choose any of the kegs K3¬-K10 that resulted in a green light. Meaning this can be concluded in 8 tests or less.

Total: 9 + 8 = 17 All of the eight tests result in a green light: This means that K2 contains beer, resulting in the pair K1,K2 being chosen.

Total: 9 + 8 = 17

Congratulations to Jankatiri and Ferenc for finding the correct solution. They won a brand-new tablet!

As per usual, each group gets a bag of materials that they can use for the project. This bag contains 1 thin plate of metal (50x30 cm), 5 m4 bolts, 6 washers and 3 nuts for the m4 bolts.

All these materials are stored on a sizable shelf with 67 compartments, conveniently labelled 1 to 67. After two weeks, as the groups prepare to construct their projects, they discover that their materials have been rearranged.

A week prior, the tutors executed a prank on the students, following this sequence: The tutor of group 1 consolidated all individual bags into a large pile for every tutor to claim.

The tutor of group 2 put one bag back in all the second compartments.

The tutor of group 3 altered the contents of every third compartment: if there was a bag, it was removed, and if it was empty, a bag was placed there.

Tutor 4 changed the content of compartments 4, 8, 12, 16, 20, 24….

This pattern continued to the tutor of group 67.

Now, the question arises: which groups were unfortunate and had their materials stolen?

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 January 2024!

The winner will be notified and announced via the social media channels of Simon Stevin.

Sponsored by:

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