Year 34 | Edition 1 | February 2016 Main article 3d printingoffunctionalstructures Lustrum edition To infinity Celebrating thepast,into thefuture, Talented and ambitious electrical engineers

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Witteveen+Bos Van Twickelostraat 2 Postbus 233 7400 AE Deventer 0570 69 79 11 0570 69 73 44 www.witteveenbos.nl engineering: people’s work presidential note Presidential note

Dear members, as you may have noticed, this first Vonk is a lit- tle bit later than usual. This might be partially due to me, as the trees were of a nice Scintilla-red colour when I started writing this presidential note, but now that I am finishing it, there are only a few leaves remaining on the rather bare trees. But as the trees turn bare, my collection of memories and stories from my board year only seem to grow.

When you read this note, I might al- chuckle now and then. Unfortunately, ready be halfway through my board my isolation in the Scintilla room has year. The first year students who are somewhat dampened my knowledge of 11-Bierentocht building their solar inverter may have any newsworthy items (which, I have to noticed that making electronics work note, is primarily my own fault by the woensdag 17 februari also requires some magic. The second way; I get distracted easily, especially 17:30, Abscint years will have almost finished one of with the abundance of long stretched the most challenging quarters of our discussions going on here). I can howe- course but will also be working one of ver report on the status of the things I the cooler projects we have: building can see from my comfy desk chair here: an autonomous hovercraft. The third a new coffee bar has opened a few me- years, well they will be close finishing ters from here, the pair of scissors has MILFBA whatever adventure they have chosen gone missing and for the weather, we donderdag 18 februari for their minor and be on their way to don’t open the windows as much any- 18:00, Abscint wondering about what to do after their more, so I think it has been getting col- bachelor. der. I guess taking a walk outside now Most of us are busy with more than just and then would be a good new years education though. I myself for example resolution. thoroughly enjoyed Scintilla’s activities the last couple of months. Once every To the new year! 91st Cantus Scintillae five year we celebrate a very special bir- donderdag 25 februari thday with a month of activities and this Dames en heren, 20:00, Abscint & Educafé year I had the pleasure of experiencing Op de koningin, op Scintilla! this spectacular event. Starting with a visit from the 1st board, followed by a month full of activities and concluded by a magnificent gala, it was a month that will be in my memories for a long Scrapheap challenge time. A good opening note combines vrijdag 15 april a few internal events and some recent Shing Long Lin 20:00, Educafé events into a nice piece which is inte- President resting, makes one think and elicits a

year 34 edition 1 3 tabletable ofof contentscontents table of contents

Most people consider 3d printing as a crea- Things have changed with the Vonk you are tive hobby. the TST group however see it as reading right now. To give an impression of Masthead a key technology for technological progress how we came to this new format, we made a Editorial in the medical world, robotics and even ae- trip to the press for you! Here we got infor- De Vonk ronatuics and astronautics! In this article a mation about the old fashioned and the di- Periodical of E.T.S.V. Scintilla. Publis- nice presentations of the almost endless po- gital version of printing and the new way of A new year hed four times a year in the amount Main Article 10 sibilities of 3d printing will be given. printing which made this Vonk the way it is. 33 On Location of 700 copies. 2016, the year after the Scintilla Lus- trum, working on a Vonk with a perfect year 34, edition 1 new design: smaller and better. Whilst October 2015 writing this article, I sit next to one of This year is a lustrum year for Scintilla, and In this junction Mark Bentum, director my lovely committee members who is Editorial team not just any lustrum, but the 50th lustrum! of the study electrical engineering, talks swearing on the articles which refuse to Tim Broenink, Guus Frijters, Lynn In this Vonk we take a look at some acti- about his experience as a student, a tea- adjust to the new lay-out. Bruins, Mark van Holland, Jippe vities organized so far to celebrate this an- cher, and a director. He also talks about Rossen, Céline Steenge, Maarthen niversary, like the gala diner and the actual his home life and other interesting and But more about last year, and the plans Thoonen, Nahuel Manterola. Dies. fun things to know. for this year. Last year a lot went on: I Lustrum 30 10 Junction studied, broke my ankle and studied Cover Artist less. I tried to give the first years a terri- Robert Fennis fic camp during the Kick-In, created my own type of Puck in the theatre show Print Midsummer Night’s Dream of Shake- Gildeprint, Enschede Presidential Note Lustrum speare, and of course did a lot more. As Celebrating out past, into the future, you all know, the Scintilla-lustrum was Editorial office 3 30 to infinity also in 2015, which meant a lot of ac- E.T.S.V. Scintilla, University of Twente, tivities, with a lot of fun, laughter, and Postbus 217, 7500 AE Enschede, Education On location drinks. 0031 53 489 2810 0031 53 489 1068 Three years into TOM What is this? it’s smaller [email protected] 6 33 After the Lustrum, December started. And we all know of December, the most Material News Junction expensive and stressful month of the [email protected] year. Sinterklaas, Christmas, and new 8 News for the electrical engineer Mark Bentum 35 year. All fun activities, but all costly due to shopping, presents and timewise due All members of Scintilla receive De to the traveling. Vonk free of charge by post. Main article Solarteam 3D printing of functional structures Red One Go But what about 2016? First off all I Nothing in this magazine may be du- 10 39 would not want to break my ankle plicated or copied without explicit again, and I am not going to think of permission from the editorial team of Symposium Column all the stressful days in December at the De Vonk . moment. I am also not the person who Impressions of a freshman 21 41 makes all kind of new years resolutions, The editorial team reserves the right to but for this editorial I will try to think change or exclude material provided Photopage Column of some things I would like to achieve or by third parties, in part or in whole. accomplish. On of the most important The opinions expressed in the articles What next? things is getting some nice ECTS. Sadly, are not necessarily shared by the edi- 22 42 this has proven to give me some trouble. torial team. But who can blame me? I just like to do New Board Puuzle fun activities with friends. ISSN 0925-5421 year 34 The 86th board year 34 4 edition 1 edition5 1 24 43 Guusje Greenteam 28 Setting course for a victory in 2016 yearyear 34 34 year 34 5 4editionedition 1 1 edition 1 education education

nation regulations, in short often called and therefore it was passed further on to blem seemed to be a shortage of people the OER. The StOEL, the program the educational committee. Although it who can give these tutorials. Three years into director and some more teachers are all could not be fixed in the same year, this After the first test StOEL concluded part of this group. subject is now going as smoothly as it that the lack of practical knowledge was should be going. so bad that theoretically less than 10 What is happening Furthermore some of the subjects co- percent of the students in the 6th mo- vered in dynamic systems (ESD) are dule would pass if nothing was changed. now? now removed, such that the 3ECs that Therefore the StOEL asked members of TOM are given for this subject use 3EC worth Scintilla to organize some extra lectures Now that modules 1 and 5 are finished, of time and not 6EC. Moreover the tests with tutorials and extra homework pro- 2 and 6 have started together with some are changed from a multiple-choice to blems that can be solved in order to mas- minors. The 1st and 5th module went ter the material and gain the required pretty smooth, but as long as I have been knowledge of an electrical engineer. on this university (and probably even Because the results of the tests are not long before), the 6th module has been known yet as of when I wrote this arti- one of the most difficult modules in the cle, I cannot conclude the effectiveness bachelor and therefore always has been More than three years passed since TOM (Twente Educational of this. But it seemed that the students giving problems. Model) started at the university and a lot of education related who attended this lecture now at least Educational get the basics of dynamic systems. Now changes have been made. The main startup implications are re- Affairs solved and the rest of the still apparent problems are being dealt What changed? that new lectures are being organized as I write, I am sure that the material will with. But what is actually still going on behind, apparently, closed The things that the educational com- open answer test. This is done so that if be better understood and with that, the doors? 86th tilla mittee together with the module coor- one understood the material but made grades of the test will go up and result Boar . Scin d of E.T.S.V dinator, program director, StOEL and a calculation error, one would still get in a humongous passing rate for this Why TOM? to make drastic changes in order to keep bers of Scintilla in the URaad, which is staff changed in comparison to last year, some points for understanding of the subject. the status of university and so TOM was the organ which has authority within and thus differ from this one, are the fol- material. Three years ago TOM started as a fresh invented. the university and regularly speaks with lowing: Although these things have been im- new method of teaching students the Of course it was not that simple and the University Board. In module 6 there was a problem with plemented this year, there are still some materials they needed to know in order alternatives where discussed, but it the material and the availability of the problems with this subject. The biggest What to expect later in to get their bachelor’s degree and with seemed that the change that was neces- What are they and teacher of the subject control systems. one seems to be that there are no tuto- that the necessary knowledge that an sary had to be big and therefore TOM The StOEL concluded this and passed rials and therefore a lack of practical this year? electrical engineer needs to know. For came out as the best option. what are they doing? it on to the teachers first, but this didn’t knowledge. The program director asked many the change to TOM was seen as a give the result that they were looking for the teacher about this and the main pro- Most of the problems that occur during ridiculous one and one that would make What is happening Let’s start by explaining the structure a one module can be solved in the same student activism impossible. little bit more, since it’s quite complica- year, but some take a little more time. Yet the truth may be told why the uni- now? ted. Each module has a module coordi- Therefore evaluations, and a lot of them, versity actually started to implement nator and has a team of teachers below are being distributed over the students. TOM. Now that TOM has been here for over them, where every teacher is assigned These are being used to make the mo- TOM was mostly advertised as a great two years, to most students it may seem to a different part or subject of the mo- dule even better next year. new way of teaching students, and as a that everything will stay the same. Yet dule. This can be the project, math and/ For example in module 8, which is co- showpiece for the UT, but getting extra the study is still far from perfect. There- or regular EE subjects. The teachers of ming later in this year, the workload for students was not the real reason TOM fore there are multiple instances in the the subjects then form said part and, as- the students (and some teachers) was was invented. The main reason for university that talk to each other in or- sisted by PhDs and student assistants, just way too high. Therefore the educati- TOM being that students took too long der to solve any problems that pop up, make sure that it is taught properly. onal committee decided that some parts to finish their studies and the three years to keep the study up to par. The educational committee, named the just had to go. Since the rest of the mo- that were scheduled for the bachelor Scintilla itself is also a part of this web of OLC, overlooks if all is going well and dule was quite alright, this will probably became mostly four, five or more years, instances and has influence by using or- tries to steer it into the right direction be the only big change in this module. with only a handful actually getting the gans like Scintilla’s educational commit- again if it’s not. In order to do this the The effectiveness of this change will be degree in time. This was not only a pro- tee, also known as the StOEL. One of educational committee comes together clear later this year, but I am looking for- blem for EE but also for other studies the board members is specifically assig- about once a month and talks about the ward to the result. at the university. Under pressure of the ned as commissioner of educational af- problems that pop up. They are also res- Dutch government the university had fairs. Furthermore there are some mem- ponsible for the education and exami-

year 34 year 34 7 6 edition 1 edition 1 news news

des and low frequencies, it is difficult to effectively harvest electrical energy from News for the these movements. This group has deve- loped a system to harvest this energy based on a tribolectric nanogenerator, a system that works by physically ma- nipulating two materials with opposing surface charges, a power management electrical engineer circuit and a energy storage device. This device provides continuous dc energy at 7.34W/m^3. In previous editions of the news we searched the internet for inte- resting information. This time we decided to get news from a lot Source: http://tinyurl.com/vonk3411 closer, and asked the various research groups closely related to Electrical Engineering at the University of Twente to send in ar- Driving on metal ticles about their own research. In this section you will read about Figure 3: Calibration curve of the standard potentiometric measurement. The open circuit poten- the doings of the research groups which sent in content. A special tial of the Ag/AgCl electrode w.r.t to a liquid reference electrode is plotted against the logarithm of A reserach group based at McGill Uni- the chloride ion concentration. thanks to them for cooperating in this! versity have proposed a way to replace a silver-silver chloride (Ag/AgCl) elec- The presence of these ions initiates pit- fossil fuels with a metal particles. The Kelvin probe as a trode, which is a chloride ion selective ting corrosion in the reinforcement steel Prior research at the group showed that electrode, is used as a sample plate in and ultimately results in the failure of metal powders suspended in air allow a new type of reference the electrolyte and the Kelvin probe is the structure/construction. For electro- flame to be sustained similarly to orga- electrode for electro- used as a reference plate that is vibrating chemical measurement of chloride ion ning gasses, which results in the metal chemical sensing above the electrolyte, see figure 1. The concentration in concrete the limiting oxide as waste product. As there is a mi- electrode potential, also called open cir- factor is the stability of the reference riad of techniques to turn metal oxides cuit potential (OCP) of the Ag/AgCl electrode. A solid state contactless refe- back into metal powders, this appears to Author: Yawar Abbas, Researcher at the electrode is a function of the Clˉ con- rence electrode such as the Kelvin probe be a sustainable way to transport energy. BIOS lab on a chip group, University of centration. The measurement setup is can be used for long-term in-situ mea- The proposal is to create a prototype Twente. Figure 2: (a) Snapshot of the electrochemical cell along with the Ag/AgCl electrode chip and the shown in figure 2. There is no contact surement of chloride ion concentration burner that can burn a stock of metal Kelvin probe (b) Snapshot of the measurement setup, Kelvin control is used to apply backing po- between the reference plate and the inside concrete. powder to generate heat for an external For the first time the chloride ion con- tential and signal to vibrating probe, oscilloscope is used to monitor the CPD. For measurements, electrolyte. The contact potential dif- combustion engine. The waste oxides centration in electrolyte is measured the electrochemical cell is placed in the Faraday cage. ference (CPD), measured by the Kelvin Self-charging biome- can then be collected again and recy- using a Kelvin probe. For a long time sensing. (sample plate). The distance between probe, gives the OCP of the Ag/AgCl cled. now, the Kelvin probe has been used for The Kelvin probe, which is basically a the plates changes periodically due to electrode i.e. measuring the chloride chanical system Metals might have a lower specific measuring work function in gas sensing parallel plate capacitor, is well-known the vibrating plate and thus the capaci- ion concentration in the electrolyte, see energy (kWh/kg) then fossil fuels (see applications and surface potential mi- for determining the work function of tance changes repeatedly, generating an figure 3. This approach opens the pos- Researchers at the Georgia Institute of picture), but they excell in energy den- croscopy. Recently, this instrument has a surface. One plate of the probe (refe- alternating current (AC). This current sibilities for using the Kelvin probe as a Technology, have developed a universal sity (kWh/l). Combined with the ready also made its way to electrochemical rence plate) vibrates over another plate can be reduced by applying a poten- contactless reference electrode in elec- self-charging system to harvest energy availability of Iron oxide, the metal pro- tial in reverse polarity, also called the trochemical measurements. Chloride from random biomechanical move- posed for the prototype, makes metal a backing potential, in the circuit. The ions are one of the major contributors to ments. As human biomechanical energy better fuel than dinosaurs. value of the backing potential, VB, at degradation of reinforcement-concrete. is characterized by fluctuating amplitu- source:http://tinyurl.com/vonk3412 which the current is completely nulli- fied, is equal to the potential difference between these plates, also known as the contact potential difference (CPD). Now, if the reference plate is in an inert environment, i.e. its work function is stable, and the sample plate is in the elec- trolyte, the change in CPD is a function of the change in the electrode potential Figure 1: Schematic of the working principle of the potentiometric measurement using a Kelvin of the sample plate. In this experiment probe

year 34 year 34 9 8 edition 1 edition 1 main article main article 3D printing of functional structures

Fig. 1: A few examples of 3D printed objects. (a) The 3D printed car ‘Blade’ by Divergent Microfactories. (b) CAD drawing of a 3D printed hand exoskeleton for rehabilitation purposes [6]. (c) Rolls Royce uses 3D printing for engine parts [6]. (d) Stent like structure printed by stereophotolitho- graphy. Note the scale bar. [3]. (e) House printed by the Chinese company Yingchuang. (f ) CAD drawing of a 3D printed LED [7] The technology colloquial known as ‘3D printing’ has developed materials can be found in [5]. Some printing most often the powder (aerospace industries, robotics, in such diversity in printing technologies and application fields examples of (to be) 3D printed objects not used in a print can be reused medical devices (surgery, prosthe- that meanwhile it seems anything is possible. However, clearly the are shown in Fig. 1(a)–1(f ). in the next. tics)) where tooling costs would ideal 3D Printer, with high resolution, multi-material capability, • Integration: functional and struc- forma major part of the total costs. fast printing, etc. is yet to be developed. Nevertheless, one can al- 3D printed objects tural parts may bemonolithically • Crowd-sourced brainpower, since ready start to wonder what possibilities for electrical engineering integrated. AM is based on digital designs everywhere. Really? • Metamaterials: like with chemis- they are easy to distribute and applications will become available in the near future. Here I try to try and nanotechnology 3D (mul- share and therefore one can bene- give a brief and balanced overview of current developments and a 3D object, not withstanding gravity and With so much press coverage 3D prin- ti-material ) printing may enable fit from a large intellectual effort few examples of the first small steps towards 3D printed transdu- other deal-breakers [1]. The amounts ting is hot, and likely overhyped. So we new meso-scale material proper- (compare open source software). cers. of material added are tiny with respect could safely put it aside and concentrate ties. Think of pseudo piezoelectric Also benchmarking materials, pro- to the overall scale of the object to be on other things, e.g. what to do during materials, negative poison ratio cesses and equipment is relatively made, but in absolute terms this may the European soccer championship this materials, anisotropic thermal straight forward. Introduction mean something completely different summer, how to found the next inter- conducting materials, host loa- • On the fly quality control using ca- form. For example by jetting small clods when e.g. talking about 3D printed net blockbuster company, etc. But this ded printable materials (e.g. with mera’s or other near-field-metrolo- of material, by solidifying particles by a concrete houses [2] or about the sub- would be beside the reality as much as quantumdots [7]), etc. gy produced parts can be directly By now, anyone that has some interest in highly focussed laser beam, by excreting micron voxels solidified by two-photon assuming that everything will be printed • Mass customisation: objects can compared to the geometrical de- how things are made, and who has not a long, thin wire and dressing it nicely in stereo-photolithography in a Nanoscri- in the near future. Let us look at some of be customised on a per device ba- sign specs. Material faults can be been hibernating in his cave, will have place, much like a glorified glue pistol, be 3D printer [3]. the bare characteristics of 3D printing: sis, just by design (e.g. 5 different monitored. Performance testing, heard something about 3D printing, or by using thin sheets ofmaterial (e.g. sensors for 5 different robotic fin- of course mostly, requires off-line or more posh ‘AdditiveManufacturing’. paper), cutting them in the right shape The technology behind 3D printing can • Enabling: things which can’t be gers...) approaches. Actually, the latter term is quite des- and putting them on top of each other be classified in 7 main fabrication-types made by any other method, becau- • Adding value: think of smart pac- criptive, especially when put opposite (much like the 3D post-cards that keep [4], each with numerous members dif- se of their inherent 3D nature or kagingwith integrated functiona- Sure enough the above may sound much ‘Subtractive Manufacturing’. Bluntly youngsters busy for the better while of a fering somewhat from manufacturer to the range of materials that can be lity (sensing, stress-release, over- like preaching to the choir. And indeed, put, many classical fabrication methods birthday party). manufacturer (if not for a difference in used seamlessly, may in principle pressure protection, etc. of Si dies, while the above is true in principle, ac- are characterised by removing material quality, then at least to circumvent in- be made by 3D printing [1]. or other components, inside) tual practical fabrication can be hampe- from a given chunk of material, e.g. by What all 3D printingmethods have in tellectual property rights). With each • Limited use of materials: In 3D • Prototyping can be extremely fast. red by: milling, eroding, abrading, grinding, common is that structures are built layer of the 7 methods comes a range of prin- printing you only need material • Fabrication can be speeded up since etc. In additive manufacturing, on the by layer froma digital description of the table materials, minimum feature sizes, to add to the object and virtually no tooling is required. This is espe- • Lack of resolution. Although vari- other hand, parts get shaped by adding object. It can be shown mathematically physical properties, etc. A brief over- there is no waste, like e.g. with mil- cially valuable for industries that ous printing methods can deliver tiny amounts of material to a developing that such a method can built any kind of view of these methods and printable ling. Even in powder-bed based operate on small series markets print resolutions from sub-micron

1: Not withstanding the z-weakness, some companies claim really large strengths and even replace metal part by printed carbon fiber and Kevlar [8]. year 34 year 34 11 10 edition 1 edition 1 main article main article

Ok, so 3D printing may not be the holy grail, but it certainly has produced some imaginative products and solutions. Let us have a look at some of the developing application fields. Medical

In the field of medical applications 3D printing has been shown to deliver very attractive solutions for problems that Fig. 3: Left: 3D printed robotic hand, from [15]. Right: 3D printed ‘RoBird’ from Clear Flight Solutions require ultimate customisation: pros- thetics. There are plenty of examples technology would also be interesting for nautics ‘Rutherford’ rocket engines that contain of fingers, hands [9], lower and up- robotic applications. mostly 3D EBM printed metal parts, per limbs that have been printed to be Until recently mostly plastic printed amongst them the most essential ones. functional, aesthetic and well fitting the Robotics parts, for non flight essential purposes, body. Also, some of the artificial hip and found their way into airplanes. Think The 3D printing hype knee replacements are nowadays 3D of parts around the windows, seats, etc. printed. Dental applications form ano- In robotics 3D printing has been adop- The main advantage here is the high Fig. 2: (a) Affordable desktop 3D FDM printer. (b) Professional 3D FDM printer. ther important field where 3D printing ted quite well, especially in research en- strength to weight ratio that can be So, overrated expectations on the one to millimeter size, none have both from a second source and need forms a cost vironments; just have a look at all things obtained by freeform structures. Metal hand and some tangible demonstration a high resolution and a large build to be removed afterwards. This effective alternative to hand made arti- printed in the Robotics And Mechatro- printing processes increasingly help to of 3D printing possibilities on the other volume. Limited resolution also removal may pose its own limita- ficial tooth for example. The use of 3D nics group of our own EE faculty! The move 3D printing into flight essential hand seem to strive for equal attention. may result in large surface rough- tions to the printed object. printing technology for the fabrication technology is interesting since it allows parts. Rolls-Royce has developed the Gartner tried to make some sense out of ness, excluding specific applicati- • Lack of reproducibility. Many of of mock-ups of body parts to allow sur- for a sufficient large materials selection XWB-97 engine with some large tita- all of this by projecting the technology ons. the more affordable 3D printers geons to visualise, prepare and train for for the envisioned purposes, for the free nium parts printed by electron beam against a maturity model [17]. In this • Lack of printable materials. Not all and used materials have limited operations is yet another example.Me- formfabrication of structures, some of melting (EBM). The part measures no model some applications of 3D prin- materials can be printed, limiting environmental control leading anwhile some of these applications ha- which cannot be made otherwise (at less than 1.5 m diameter times 0.5 m ting are still well before the ‘expectati- the range of what can be made to limited reproducibility of the vematured quite significantly and lead least without assembly) and delivers thickness! New Zealand based Rocket- ons peak’ of the hype, to which I hap- for specific purposes (other than printed parts. Good reproducibi- to large economic activities. E.g. have a results with very short lead-times. On Lab has developed the ‘Electron’ and pily dedicate the printed transducers of the bling-bling and smart-phone lity is generally only obtained by look a the medical page of the website the transductive side, integration of sen- covers). far more expensive professional of the Belgian additive manufacturing sors starts to be addressed increasingly, • Mechanical properties. The me- machines. service Materialise [10]. where medical and robotic applications chanical properties of most prin- • High per part cost. 3D printing is More scientifically driven, 3D printing sometimes almost merge. I.e. an or- ted objects showlarge anisotropy mostly competitive for single or is investigated as a means to print hu- thosis (exoskeleton) to assist in patient as the layer by layer deposition small series products. The advan- man tissues [11] or scaffolds on which movements may come close to a robotic basically introduces structured tage is that no tooling is required natural tissues can grow optimally. part as far as function and hardware is inhomogeneities and associated and lead times can be extremely Think of veins, cartilage, etc. And by ex- concerned, though the required control variations in virtually every physi- short. The disadvantage that the tension of the concept of tissue printing may differ significantly. cal property of the material. Note- time needed to print a product one also findswork on printing of entire Particularly interesting from a design worthy is the problem of reduced is relatively long, certainly com- organs [12,13]. point of view is that 3D printing al- strength in the z-direction, i.e. the pared to techniques like moul- A Stanford group lead by Zhenan Bao lows for a strong degree of biomimetic direction perpendicular to the ding, spray-casting, punching, [14] has developed artificial skin in the design. Now, not only can principles layers, due to limited adhesion etc.,making 3D printing less suit- form of thin layers with printed elec- from nature be used in robotic designs, between the consecutive layers. 1 able for large series products. trodes and organic transistors which but even the used shapes can be virtually • Need for support structures. Alt- • High energy consumption. The transduce pressure signals into fre- recreated. The ‘RoBird’, developed by hough any object can be 3D technology has much to offer but quency modulated digital pulses. It was Clear Flight Solutions, is a nice example printed in principle, gravity may this comes at a price of using (far) subsequently shown in vitro that these of the latter. require additional internal and/ more energy than for regular fa- pulses could optically stimulate optoge- or external supports. These need brication, for example moulding. netically engineered mouse somatosen- Aeronautics & astro- Fig. 4: Left: 3D printed bearing housing of a Rolls-Royce XWB-97 engine [6]. Right: the ‘Ru- to be co-printed with the object sory neurons. Obviously, the developed therford’ rocket engine developed by Rocketlab [16].

year 34 year 34 13 12 edition 1 edition 1 main article main article

Over the last two decades computing pic they have drafted a roadmap [18] in and communication has seen an incre- order to assess the future needs for sen- dible development. With the internet sor as well as to address their fabrication. in the palm of our hands it is hard to Interestingly, the resulting matrix shows believe that it is only 15 years back that 3D printing to be thought capable of Google was founded! And sure enough fabricating sensors for all applications. many more developments are still So this poses the question: ‘how will ahead of us. High expectations about 3Dprinting become a viable technologi- the future connectedworld have been cal platform for transducers?’. condensed in catchy phrases like The internet of things or even The internet A technology preceding 3D printing is, of everything, Industry 4.0 and Real of course, 2D printing. Although this computing2. What all these concepts is an entire subject of its own, it is inte- have in common is that they heavily rely resting to see howmuch meanwhile has on a variety of sensors to obtain infor- become possible with printed electron mation from the environment, machi- ics. Probably one of the most imagina- nery, humans, engines, etc. This has led tive examples is the work by TNO. They Fig. 7: (a) An 8 bit electronic digital processor a consortium of people engaged in sen- have demonstrated an 8 bit electronic with printed-programmable memory by TNO. (b) A quadcopter with included electri- sor research and development to think digital processor based on organic tran- cal wiring printed by a Voxel8 printer. about the future of sensor fabrication. sistors with inkjet print-programmable Considering the age of abundance3 they memory [19]. this article as well, whereas others have predict that somewhere between 2020 reached a more stable expectation pla- and a few years later the number of sen- Obviously, 3D printing of electrical and Fig. 5: Maturity model in the analysis of the 3D printing market according to tech research company Gartner [17]. teau. In the report Gartner emphasi- sors employed in our smartphones, cars, electronic structures is nowhere near ses the scale and speed by which 3D utility devices, environmental sensor as developed as to where silicon tech- TApps . Smartenergy generation 9.and control Minimallymonitoring invasive health 4. printing is being introduced in the networks, medical equipment, etc. will nology or even printed circuit board 0 Digitalmanufacturing, printing3D 10. medical world, leading to (too) high exceed accumulatively a trillion sensors. technology is nowadays. However, there

Precisionaquaculture agricultureand TSensors Roadmap . Noninvasivehealth monitoring 3.

DNA/Genome/RNA/Protein based DNA/Genome/RNA/Protein expectation, but also stresses that the Hence they have aptly called themselves is a, for those anticipating, slow, but cer- . Education: sensors and IoE 2. fabrication of customised hearing aids the Trillion Sensors Roadmap group. tain development of technologies for a Environmental sensing 7a. b Infrastructure sensors 7b. Quality, pollution, freshness Harsh environment sensors environmentHarsh . Smartfood production8. Homeenergy management diseaseChronic monitoring diseaseChronic monitoring Autonomy brain for drones

Autonomy brain for robots and dental products by 3D printing Organising various summits on the to- the printing of electrically conductive Bridges, roads,buildings Biometric authentication Petrochemical pollution Planthealth monitoring . Computer senses 6. . Personal imaging 5. has already firmly settled. Knee and hip Explosives detection Agricultural pollution Digestible pillbased Water management Smart grid sensors Smart sensing City Body fluid analysis Radiation pollution replacements are expected to become Table 1: Overview of resistivities of some conductive (print) materials Bodyfluid based Livestock health Livestock Assets tracking Assets ae pollution Water Emotion based Contact-based

Breath-based mainstream playground for 3D prin- Voice-based Non-contact Air pollutionAir ting due to positive trials and the scale Touch Vision Taste Smell of the market. For a variety of applica- Feel Sensor Technology tions the graph indicates the current Platforms maturity with respect to 3D printing Spectrometer opportunities. Clearly, some are ahead Gas chromatograph Chemical sensors of the curve andmay be overhyped, but Lab-on-Chip others have become mainstream in their Lab-on-CMOS Paper Microfluidics respective markets. Disposable cameras Acoustic imaging Hyperspectral imaging Printed electronics Thermal imaging Ultrasound imaging Xray imaging and transducers THz imaging Radiation sensors Brainwave sensors The internet of everything 3D printed sensors 3D printed ICs & 3D printing Graphene sensors High temperature sensors 2: Meaning that whatever we have in the shape of digital designs in our computer can take on real shape using digital fabrication methods like ad- Fig. 6: The sensor needs versus fabrication technologies matrix as produced by the Trillion Sensor Roadmap group, from [18]. Yellow marking by the ditive manufacturing, CNC, etc. author. 3: Abundance is the termto denote that fabrication of products will become increasingly cost-effective, productivity growing faster than the world populations demand such that all products will become in reach of each person on the planet.

year 34 year 34 15 14 edition 1 edition 1 main article main article

6000 electrodes. This implies that actuation is Water of the ions in the moving fluid in com- going to be hampered. However, sensing Acetone bination with manually assembled mag- generally requires far less power and 5000 Potassium Hydroxide nets. The sensor is made out of two 3D Ethanol therefore is still possible. Comparing printed parts which, when put together,

the different solutions for electrically 4000 form a channel and which allow for easy conductive printing we can observe that mounting of the permanent magnets the range of conductivities is large. and electrodes to measure the flow in- 3000 duced potential difference. Experiments Clearly standing out is, of course, cop- indeed showan acceleration dependent Material loss (mg) per. Reason for theMacDonalds group 2000 output voltage.However,we find strong of the University of El Paso to concen- contributions from other than electro- trate on a different approach. In their magnetic sources which, due to their na- 1000 3D printed electronics work they use ture and magnitude, are interesting for Fig. 8: Various phases in the 3D printing of a motor. After each phase some parts are embedded robots to lay down tracks of copper further research. (from [29]) 0 by a robot in a stop-and-go process 0 0.5 1 1.5 2 2.5 3 Time (s) 4 materials. Some are based on doping of devised a process in which they use sa- [27,28]. This way it is even possible to x 10 Printing of intricate structu- well-known print materials like polylac- crificial material, i.e. they print with 3D print motors [29], cube sats, elec- tic acid (PLA, an organic environment (at least) two materials, one of which tronic dice, etc., admittedly using some res friendly and bio-degradable material) is non-destructively and selectively assembly as well. In an another project we have investi- or acrylonitrile butadiene styrene (ABS, soluble after printing [21]. Once the gated the 3D printing material jetting- the stuff that Lego bricks are made sacrificial material is dissolved they im- 3D printed transducers process for the fabrication of intricate from). Other manufacturers design and pregnate the resulting channels with sil- structures [31]. Normally, any required market printers and materials that are ver particle based ink and let it solidify. In the Transducers Science & Techno- support material is removed by brute specifically meant to print conductive They show that it is possible to use this logy group we conduct research on 3D force water jetting. We investigated the inks, mostly based on silver particles. technology to make LC-tank oscillator printed sensors. The idea is that to start chemical dissolution of Fullcure 705 z x E.g. Voxel8 [20] is such a start up. In type sensors for measurement of the die- making sensors one only needs the capa- 1 mm support material their commercial material they show lectric constant of dairy products. bility to print structural, dielectric and while minimally affecting Fullcure 720 how a quadcopter is made by a stop- conductive materials. By allowing struc- 800 structural material. From several sol- and-go print process, i.e. the printing is In printing of electrically functional tures to be deformable a transductive vents ethanol turned out to be the best 700 stopped various times to embed electro- structures one of the important points operation is obtained. This way one can with respect to selectivity and dissoluti- nic components but the electrical wiring is the conductivity of the electrodes, easily envision e.g. piezoresistive, capaci- 600 on speed. We found that the dissolution is by 3D printing of silver ink. see table 1. Obviously, low conductivity tive, magnetic and other sensors. process can be theoretically accurately does not allow for high current densi- 500 described by the Noyes-Whitney equa- Recently researchers from Berkeley have ties since Joule heating will destroy the tion, implying that the development of 400 various structures can be predicted quite well. The fabrication process was used 300 to make various 5 mm diameter mem- branes, ranging in thickness from 112

De ection w of membrane (µm) 200 Membrane de ection to 768 μm and their mechanical perfor- 100 Plate de ection mance was characterised, see Fig 10(c). Measurement Data The theoretical shapes for membrane 0 0.5 1 1.5 2 2.5 3 3.5 (blue) and plate (green) behaviour are Fig.10: (a)Material loss for Fullcurex location 705 support on membrane material (mm) forWater, Acetone, PotassiumHy- compared with the shape of the realised droxideand Ethanol. The dissolution process can be described using the Noyes-Whitney equation membrane that was pressurised by 300 [32]. (b)Cross-section of a 112 &mmembrane under optical microscope after gold deposition and mbar (red dots). Clearly the structure slicing. (c) Measured membrane shape under a uniform load of 300mbar (red dots). Angular acceleration sen- behaves like a membrane. and fish [30]. The sensor consist of a sor fluid filled circular channel. When -ex 2D force sensor In the MSc. work of Joël van Tiem we posed to angular accelerations the fluid have investigated a biomimetic angular flows relative to the channel. Read-out For robotics and rehabilitation purpo- acceleration sensor inspired by the ves- is based on electromagnetic flowsensing ses, the sensing of interaction forces, tor- Fig. 9: (a)Design of the two separately 3D printed parts that formthe sensor (left) and the assembled sensor (right). (b) Voltage as a function of angular acceleration. tibular system, as found e.g. in mammals using the pseudoHall effect by means ques and pressures on soft materials that

year 34 year 34 17 16 edition 1 edition 1 In this case it is important to keep track of the retraction of the filament. With retracting filaments the amount of molten material in the nozzlecham- ber can be limited. Flexible materials leads to ooze more then other ones, here it is important to prevent enough material at the beginning of the print (Printer Settings Extruder x Retraction when tool is disabled (ad- −! −! vanced setting for multi-extruder setups) Extra length on restart: e.g. 5 mm). Slic3r on its own o↵ers a ooze prevention using to lower the tempera- ture of each nozzle separately(Print Settings Multiple Extruders Ooze −! −! prevention). It has to make sure the temperature variation is set that the nozzle will cool down to the point till it stops oozing (e.g. 60), all fila- ment temperatures has to be entered. Before starting the print it has to be ensured that the first extruder is selected.

4.5 Printing a Force Sensor At the end of the internship it was possible to print a working force sensor. The device is realized with the previously used filaments. The conductive one is used as the plates of a capacitor configuration which are spaced by a special shaped flexible material. The conductive areas are covered with a layer of PLA to guarantee a uniform force distribution and to protect the surface.

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Ctot/Cref versus number of wires 1.5

Ctot/Cpp

Ctot/Cww

1 ref /C tot C

0.5

0 12345678910 # of wires

Fig. 11: (a) CAD rendering of a proposed Normal
force 3D printed 2-DOF force sensing system. (b) Normalised capacitance versus number of Fig. 12: (a) The first transistor, invented in 1947. (b) A printed, bulky capacitive sensor, 2015. -12 ×10 Charge-distribution over wire pairs wires for a structure of 10mm x 10mm size, materials. Understanding, model- QQ*1.1 Shear
force Q a gap of 2mm and a wire diameter of 1mm. DOI: 10.1109/BIBE.2013.6701672 6 ling & application of the various the free-formcapabilities to make (c) Fabricated prototype sensor parts using AM technologies for transducers new, exciting transducers, charac- NinjaFlex FDM material and a MakerBot [2] TU Eindhoven starts using king- 5 research. terise them, etc. Replicator 2 3D printer. Figure 21: left, test setup; right, printedsize 3-D forceconcrete printer: sensor http://phys. • Single material printing: Form- • Systems integration and applica- org/news/2015-10-tu-eindhoven-king- 4 fidelity, adhesion, anisotropy, ma- tion: Of course, one of the promi- size-3d-concrete.html sity. Initial results show a softer material terials properties, small structures ses of 3D printed transducer is to

Q [C/m] 3 such as NinjaFlex (Fig. 11(c)) may prove (e.g. membranes), etc. need to be embed them in other structures, [3] Nanoscribe, information retrieved- to be the most compatible with thisThe sen- followingunderstood, diagram modelled and showsopti- RoBirdwings, the capacity robotic hands, hand response March 2015: ashttp://www.nanoscribe. a result of applied 2 sing system. mised protheses, etc. where they will be de/en/technology/additive-manufactu- force. Before adding• Multi material weight, printing: The ex- the sensorexposed to mechanical/thermal got strained ring/ by a pre-weight of 11.5 1 Interdigitated Top
Electrode
Conclusion tension to using multi-material loading, fouling, chemical attack, Electrode
Pattern kg to ensure toprints work implies amany proper additional sensingetc. range. The[4] testI. Gibson wasl D.W. Rosen divided l B. Stucker, in a load 0 ‘AdditiveManufacturing Technologies; 0 0.001Pattern 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 question regarding form-fidelity, x [m] If you have made it to here,and I hope by unload phaseadhesionbetween to see dissimilar the ma- behaviourAll in all, it is clear that ofexciting the things sensor.Rapid Prototyping The to Direct sensor Digital- showed now you have a somewhat better over- terials, optimisation of printing become possiblewhen merging 3Dprin- Manufacturing’, 2010, Springer, ISBN: view of sense and nonsensea of 3D nearly prin- linearconditions, response differences within layer ting loaded with electronics weights tomake transdu- between978-1-4419-1119-3 1 and 12 kg (blue ting. Hopefully you have gotten excited thicknesses, etc. that will cause un- cers. At the moment this seems challen- [5] Free 3D printing basics guide stretch on movements are required [33]. plate) capacitance can be obtained. This about future possibilities,squares). meanwhile In thedesired unload topological features, phase, stress, ging the but there capacity are sufficient indications of the sensor was higher than from 3Dprintingindustry.com: To this end, initial investigations are is an important encouraging result for appreciating the challenges that lie anisotropy etc. of progress in the 3D printing landscape http://3dprintingindustry.com/3d- underway for embedded sensing using fabrication methods where both high ahead of us in terms of technologyat the that beginning caused by the: to structurestart this endeavour now. of And, the lets polymer (red squares). • Conductive material printing printing-basics-free-beginners-guide/ novel commercial flexible elastomer ma- wire density and continuous metal sheet has to be developed, device principles How can we get sufficient conduc- face it, who would have been able to terials such as NinjaFlex [34]. In order embedding are challenging. that have to be investigated, etc. To ma- tivity while still keeping the con- predict the course of semiconductor [6] Some pictures in this article were to create normal and shear force sensing terialise any of the high expectations on ductors small, flexible, etc.? What development when confronted with the taken from news items that appeared on with one device, a multiwire structure is With a fully characterised sensor model 3D printed transducers, much research to do with anisotropic conducti- first transistor? www.3Dprintingindustry.com. investigated, such as that in Fig. 11(a). (Fig. 11(b)), a multilayer wire capaci- still has to be done, luckily!, as it pro- vity. With respect to external in- 26 Using elementary expressions [35], for tive system was designed within a 3D vides for ideas for research grants, ba- terfacing we need to sort out how References [7] Y. Kong, I. Tamargo, H. Kim, B. the electrical fields of pairs of opposi- printed structure. Initial proof of con- chelor and masters projects and exciting to connect printed conductive Johnson, M.Gupta, T.-W. Koh,H.- tely charged wires, it is possible to cal- cept structures were fabricated from a future applications. Some of the materials to e.g. platinum, copper, [1] A. Anastasiou, C. Tsirmpas, A. A. Chin,D. Steingart, B. Rand culate the capacitance of collections of variety of materials. Materials such as research that is going to be addressed in solder, silver-ink or glue, etc. Rompas, K. Giokas,D. Koutsouris, &M.McAlpine, 2014, ‘3D Printed wire pairs. The results are shown in Fig. ABS, NinjaFlex, and ULTEM 9085 the near future in the TST group: • Printed transducers: Once the “3DPrinting: Basic concepts Mathema- QuantumDot Light-Emitting Diodes’, 11(b) and indicate that even for a wire were used in the fabrication process in above challenges have sufficiently tics and Technologies”, IEEE 13th Inter- Nano Lett., 2014, 14(12), pp 7017- density of only 50%, a capacitance of order to determine the optimal correct • Technology: Selection of the most been addressed we need to use national Conference on Bioinformatics 7023, DOI:10.1021/nl5033292. 85% or more of the fully dense (parallel stiffness, filling factor, and printing den- promising print technologies and our imagination to optimally use and Bioengineering (BIBE), 2013, p1-4, [8] Markforged web pages, visited No-

year 34 year 34 19 18 edition 1 edition 1 main article

vember 2015: https://markforged. [18] J. Bryzek, Trillion Sensors move- CopperWire and CopperMesh Capa- com/materials ment in support of abundance and in- citive Sensing for 3-D Printing Appli- ternet of everything, SensorsCon 2014, cations’, IEEE Sensors Journal, Vol. 15, [9] C. O’Neill, ‘An Advanced, Low Santa Clara, CA,March 6, 2014. No. 2, February 2015, DOI:10.1109/ Cost Prosthetic Arm’, Proc. IEEE Sen- JSEN.2014.2356973 sors 2014, p494, DOI:10.1109/IC- [19] Kris Myny et. al, ‘A thin-film mi- SENS.2014.6985043 croprocessor with inkjet print-pro- [29] E. Aguilera, J. Ramos, D. Espalin, F. grammable memory’, Scientific Reports Cedillos, D. Muse, R. Wicker, E. Mac- [10] Materialise medical services, web 4:7398, DOI: 10.1038/srep07398 Donald, ‘3D printing of electro mecha- page visited November 2015: http:// nical systems’, (2013) Proc. of the 24th www.materialise.com/products-and- [20] Voxel8.com, webpage visited De- International SFF Symposium - An Ad- services/products-and-services-for-me- cember 2015: http://www.voxel8.co/ ditiveManufacturing Conference, SFF dical-professionals-0 2013, pp. 950-961. [21] S.-Y. Wu, C. Yang, W. Hsu & L. [11] S. Peltola, F. Melchels, D. Grijp- Lin, ‘3D-printed microelectronics for [30] J. van Tiem, J. Groenesteijn, R. ma & M. Kellomäki, ‘A review of integrated circuitry and passive wireless Sanders & G. Krijnen, ‘3D Printed Bio- rapid prototyping techniques for tis- sensors’, Microsystems & Nanoenginee- inspired Angular Acceleration Sensor’, sue engineering purposes’, (2008), ring (2015) 1, 15013; DOI:10.1038/ Proc. IEEE Sensors 2015, Nov. 2015, Annals of Medicine, 40:4, 268-280, micronano.2015.13 www.nature.com/ Bushan, Korea, p1430. DOI:10.1080/07853890701881788 micronano [31] J. Verhaar, R. Sanders & G. Krij- [12] V. Mironov, T. Boland, T. Trusk, G. [22] Functionalize, webpage visited nen, ‘3D printed features in the 100 &m Forgacs & R. Markwald, ‘Organ prin- December 2015: http://functionalize. range for application in sensing’, Proc. ting: computeraided jet-based 3D tissue com/product/1-pound-of-f-electric- IEEE Sensors 2015, Nov. 2015, Bushan, engineering’, TRENDS in Biotechnolo- filament-1-75mm-diameter/ Korea, p478. gy Vol-21, 2003, p157, DOI:10.1016/ S0167-7799(03)00033-7 [23] BlackMagic3D, webpage visited [32] A. Noyes and W. Whitney, ‘The December 2015: http://www.blackma- rate of solution of solid substances in [13] S. Murphy & A. Atala, ‘3D gic3d.com/product-p/grphn-175.htm their own solutions’, J. Am. Chem. Soc, bioprinting of tissues and organs’, Natu- vol. 19:930-934, 1897. re Biotechnology, Vol-32, 2014, p773, [24] Proto pasta, webpage visited De- DOI:10.1038/nbt.2958 cember 2015: http://www.proto-pasta. [33] R. Brookhuis, H. Droogendijk, M. com/ de Boer, R. Sanders, T. Lammerink, R. [14] B. Tee, A. Chortos, A. Berndt, A. Wiegerink & G. Krijnen, ‘Six-axis force [25] S. Leigh, R. Bradley, C. Purssell, D. Kim Nguyen, A. Tom, A. McGuire, torque sensor with a large range for bio- Billson, D. Hutchins, ’A Simple, Low- Z. Carter Lin, K. Tien, W.-G. Bae, H. mechanical applications’, J. Micromech. Cost Conductive Composite Material Wang, P. Mei, H.-H. Chou, B. Cui, Microeng. 24 (2014) 035015. K. Deisseroth, T. Nga Ng, Z. Bao, ‘A for 3D Printing of Electronic Sensors’, skininspired organic digital mechano- PlosOne, Volume 7, November 2012, [34] C. Shemelya , L. Banuelos-Cha- receptor’, Science 2015, Science 350, Issue 11 e49365. DOI: 10.1371/jour- con , A.Melendez , C. Kief,D. Espalin, 313 (2015), DOI: 10.1126/science. nal.pone.0049365 R.Wicker, G. Krijnen&E. MacDonald, aaa9306. ‘Multi-functional 3D Printed and Em- [26] MakerGeeks, webpage visited De- bedded Sensors for Satellite Qualificati- cember 2015: http://www.makergeeks. [15] ABC News Austrialia, web pages on Structures’, Proc. IEEE Sensors 2015, com/co3dfi.html visited December 2015: http://www. Nov. 2015, Bushan, Korea, p1422. abc.net.au/news/2013-12-04/3d-prin- [27] E. Macdonald, R. Salas, D. Espalin, ted-robot/5135416 [35] H. Green, ‘A SimplifiedDeriva- M. Perez, E. Aguilera, D. Muse & R. Wic- tion of the Capacitance of a Two-Wire ker, ‘3D Printing for the Rapid Prototy- [16] RocketLab, webpage visited De- Transmission Line’, IEEE Trans.Micro- ping of Structural Electronics’, IEEE Ac- cember 2015: http://www.rocketlabu- wave Theory Techniques, Vol. 47, No. 3, cess, Vol-2, 2014, p234, DOI:10.1109/ sa.com/index.html 1999, p365-366. ACCESS.2014.2311810 [17] Gartner web site, visited December 2015: http://www.gartner.com/news- [28] C. Shemelya, F. Cedillos, E. Ag- room/id/3117917 uilera, D. Espalin, D. Muse, R. Wic- ker & Eric MacDonald, ‘Encapsulated

year 34 20 edition 1 symposium Symposium

As part of the festivities concerning our fiftieth birthday, a symposium was organized. On the 15th of September se- ven companies visited the university of Twente to do a pre- sentation for 130 knowledge hungry electrical engineering students. The symposium committee started organizing this event almost a year before. Six dedicated Scintilla members took up the task to present some food for thought in a month full of fun. The day started at 8:30 with some cof- they could contribute to the informati- rays to scan the universe. Easily reaching fee and tea with a piece of cake (not on age. They are currently working on a the ten exabyte of data every day (!). to be confused with Scintilla’s piece of way to identify RFID tags in every pos- During the lunch, some fresh sandwi- cake committee, SPOCK). After a word sible product. They developed a scanner ches were served. As we did not want of welcome by our host Mark Bentum, that could read up to hundreds of tags to waste any time to fill with our guests Bruco kicked off the day with a presen- a second! with information, Arcadis, Dialog and tation on ‘Live streaming on Planes’. Before ASML started their presentation NXP provided them with some gad- In 45 minutes they presented how the there was some time for some muffins gets and answers to every question they data consumption of people increases and a discussion on the previous topics might have had. tremendously and how technology is during a nice cup of coffee. Then ASML After the lunch there were still presen- supposed to keep up with the need for presented their latest technology on tations from NXP, refreshing some information. They presented an imple- creating extreme ultraviolet light, by va- knowledge on die hard electronic sub- mentation of a high tech antenna sys- porizing small particles of mercury. The jects such as ADC’s and Phase Locked tem, that would allow for fast WiFi on last presentation in the morning was Loops. Technolution explained about planes. from Astron/IBM, which was about their progress on a revolutionary way of After a 5 minute break Nedap continu- some serious computing power produ- designing digital hardware using their ed the day with a presentation on how ced by the new generation antenna ar- own HDL compiler. At last Dialog closed the presentation session with a talk about how their smart sensor fu- sion is applied in wearable devices such as activity trackers. After a whole day of inspiring talks, eve- rybody was desperate for some relaxing and set themselves to a nice cold drink. For those who also signed up for dinner, a great meal of spareribs was awaiting for them at the faculty club. Thanks to all the companies involved and other parties who made this day to such a great success.

year 34 edition 1 21 Dies reception!

Viriday! Elysium!

Camp!

Gala! board board

Shing Long Lin doing things for Scintilla until I started tual high school for the teaching minor the skiing committee in my third year and with my hobby’s, playing volleyball President (and even still, with only one commit- and various other sports. tee, my committee tally, might be the As a board member, my schedule has The 86th board shortest one among this board). Howe- not exactly become less crowded, but I ver, I aim to show my face around this don’t think this is a bad thing. On the year, get to know as many people as pos- contrary, I like being busy all the time sible at Scintilla and fully redeem myself and as the president I am able to be as a true Scintillian with my board year. just that. Apart from my duties as the The formation of a new board is an important issue for an associ- Live your life to the fullest; a good commissioner of external affairs, a post ation. Selecting a group of candidates filled with enough people phrase to live by. As such, I have tried shared with my vice-president, I am to keep myself busy during my student free to take care of all day-to-day affairs capable of and especially willing to run the association for a whole life. In my first year I tried rowing in the that come up or come by in the Scintilla year is not always an easy task. Also getting these people to like ‘wedstrijdploeg’, which, although I gave Room. The post of President was the each other enough to actually last the whole year is not even pos- my all, was not a huge success and soon post I had seen myself fulfilling even sible to do every year. After a long recruitment process during the I traded rowing competitively for pou- before I had met the rest of the board. academic year of 2014/2015, the 85th board of Scintilla invited ring my efforts in getting my BSA again. This is because I often quickly take the Soon however, I got an itch for doing lead, but also because I think I am able five people over for a dinner. After this dinner, where only a sur- A ctief sinds 1965 something extra again. This is when to have oversight in the many affairs in prisingly small amount of time had to be spent on serious matters, I started teaching students, helping which Scintilla takes part. Managing the this set of people had a whole different outlook on their upcoming to prepare them for their high school external affairs is something I did not year. They had found their calling in the running of the new board exams at trainings, something I am choose at first, but it is a job that I have and they had found the people to complement themselves in run- Unlike some of the other board mem- doing with joy until this day and proba- come to appreciate. The regular contact bers, I was not seen as an obvious board bly will be doing for several more years. with all sorts of companies has given ning Scintilla for its best year: The 86th board was born. candidate by many people. After our The next year I felt ready for a new chal- me insight in the possible futures for an candidate board presentation, quite a lenge again, after I had gotten the now electrical engineer and it’s a nice chal- few surprised people noted that they retired propedeuse. Thus I became part lenge to create possibilities for compa- had hardly seen me around before. They of the Greenteam Twente, working on nies to present themselves whilst giving were not wrong in that observation the hydrogen powered UTMotive for the students a nice experience. All in all, however. Although most of my friends the race of 2014. After that I spent my it is an experience very different from were active members, I had not started time with more teaching, now at an ac- the normal student life, but I am already Erik de Groot very happy for being allowed to do this! Of the entire board I may have been the more with however. Besides the study I Secretary last person to officially decide to join the have been an active member at Scintilla 86th board of Scintilla. This is mainly since the first year, when I was a member due to several setbacks during my second of the freshmen-committee, which was a year of study and financial uncertainties. lot of fun. In the second year I helped or- However, I have wanted to be a board ganize the introduction camp of Scintilla member for quite a while despite it cos- as a member of the kick-in committee and ting a year of the study. The main ques- you may find me behind the counter as a tion was whether I would do it this year member of the STORES. or next year. This year I am the Secretary of the board I started studying Electrical Engineering of Scintilla. I took the opportunity becau- in 2013. The main reason I chose this se I wanted to learn other things that the study is because of how applicable it is, study itself does not offer. These things as the thing I enjoy the most about it is include being better at organizing, taking being able to make your own electrical responsibility, and writing with more nu- system that works. I make my own pro- ance and finesse. And of course I joined jects from time to time, such as an ampli- the board because it is a great experience fier or a stroboscope. The mathematical where you get to meet a lot of people and part of the study I have struggled a lot the things you do are very rewarding.

year 34 year 34 25 24 edition 1 edition 1 board board

Gerolf Meulman As most of you already know, my name will be the Emergency Response Officer As my task is to try and get as much Niels Leijen fun if I did a year of board and here I am. is Gerolf Meulman and I am the treasu- at an activity. I also became the treasurer members to our activities, and I am a As Commissioner of Educational Af- Treasurer rer of Scintilla this year. I was born in of the Lustrum committee. member of the borrelcommittee, I will Vice President fairs, I try to make sure that your study 1994 in Nieuw-Amsterdam (Drenthe). At this moment, I realize how difficult probably be found talking to members goes smoothly. I do this by attending Since 2012, I study Electrical Enginee- it is to write something about myself. often, and at Scintilla’s amazing aciti- Hello everybody! My name is Niels all kind of meetings (which all have ring here at the University of Twente. Writing a huge report about Electrical vites. I hope to see all of you there, so Leijen and currently in the third year of great abbreviations like: OOC, OLC, I decided to join the board of Scintilla Engineering related stuff is quite easy come find me at the borrels of Scintilla the study Electrical Engineering. This StOEL, OPEL and more), talk with more than a year ago. First, however, I compared to writing a tiny piece of text and have a drink with me! year I am one of the board members for staff members and other study associa- wanted to finish my Bachelor. So I did, about yourself. Anyhow, let me conti- the 86th board of Scintilla and will ful- tions, and all this in order to address all and this year on my birthday, Septem- nue a bit more. fill the role of commissioner of educati- kind of study related problems. ber 11, I received my bachelor degree Besides being in the board of Scintilla, I onal affairs, so if you have any (study re- Furthermore the first year students will during the graduation ceremony. will also be doing some other things this lated) problems, feel free to come to me! likely also meet me in the fourth mo- In my first year, I was not an active mem- year. For example, in the second quartile Of course I did not join the board by ac- dule of this year, since I will probably ber at Scintilla. I attended a lot of activi- I will be a student assistant for the se- cident (how can you even do that I won- be one of the student assistants for fields ties, but did not join any committees. cond module (Electric Circuits). At this der?). Before joining the board I already and waves (again…)! Here I will serve, Only in my second year I discovered moment, I am a Master student at the was an active member of Scintilla and observe and try to help you the best I how awesome it is to become an active Telecommunication Engineering chair. I joined multiple committees like the possibly can to make the best antenna as member at Scintilla. One of the com- In the third and fourth quartile I will Parents day and after that, during the possible and of course have fun. mittees I joined was SKIC. After being probably also start actually doing some Kick-in, I have been one of the do group Well I think that is in short my life in the a do-group parent for ELco 10, I was as- master courses. parents of the best do group imagina- 86th board of Scintilla. I hope that this ked to join SKIC, which was really fun. But for now, I will continue doing mo- ble, aka Elco11. This was so awesome board year will become superdupahcool In my third year, I joined the BHV com- ney related stuff as the treasurer of the that I decided to join the SKIC, which and finishing on this bombshell, I wish mittee, which means that sometimes I 86th board of Scintilla. organized this years intro camp. After you all farewell and don’t forget to have Nick te Velde a while, probably during one of the so fun during the rest of the year (and af- Furthermore, my soldering iron also has a do-group parent. No sooner said than called borrels, I decided that it could be ter)! Internal Affairs a name: Eva. done, I became a do-group parent for Now that those two important questi- Elco 11. During this Kick-in I had again Eelco Bussink a member of, a board sided view was an so maybe a story about Charlie the ons are answered, let me continue with a great time, so during my second year I easy enough choice. To finish this al- Unicorn can lighten things up a bit. A really introducing myself. When I star- decided to join more committees. Administrator ready way to long introduction, being an trip to candy mountain will be a trip ted our great study I of course went to Since I loved the Kick-In for two years administrator as opposed to a full time to heaven, for your mind remember all the Kick-In, which I found out to be in a row, I decided to have another go board member would impact my desi- the times you have been up there with simply amazing. Especially Scintilla’s at it, so I joined the Scintilla’s Kick-In res of finishing my bachelor by a lesser Charlie. Perhaps you can take a quick camp was something I really loved, with committee, also known as the SKIC. degree. So far, not much has been said. thought about all the hours you have the dropping and the cantus. During the Furthermore I joined the Borrel, since Maybe my efforts for making this easy to wasted watching Master Movies, which Kick-In, I made some good friends, with I was often at the drinks organized by read are already futile, after just the first in my mind are very nostalgic. Let’s which I did a lot of stuff in and outside Scintilla and wanted to try to tap at the sentence. For which I am not extremely hope at least a few readers of this little of Scintilla. bar. With this, my active life at Scintilla sorry. introduction are now tempted to watch During my first year, I joined the Pa- has been treated. This is of course not Of course, I could write excessively Charlie the Unicorn or Master Movies rents day committee, to organize a day the end of my ‘career’ at Scintilla, since about my history, how I was born (so- again. for (as the name implies) the parents of I am a part of the board now. In the mething with my parents having a stork I will not limber on with this introduc- all first year students. I really enjoyed it, board I have the function of Commis- delivery service over), but that is not tion for much longer. The easiest way of especially watching the parents trying to sioner of Internal Affairs. This means interesting. Until the time I went to telling who you are or getting to know a measure and calculate an RC-filter, and my responsibility is that all committees the university, I played soccer, but, after person is by, well, meeting in person. If trying to solder something. Afterwards are working correctly, our members be- problematic limb structures and driving you really want to get to know me, come I am Nick te Velde, 20 years old and there was a dinner and drink, where all come active in Scintilla and come to the into a truck, that’s off the table. Now, my to have some coffee with me and then 3rd year student Electrical Engineering. the parents said we organized a great activities Scintilla organizes. Further- focus is on lifting weights, putting them we could talk about random stuff like Now can I start with answering the day. This gave me quite a good feeling, more I am a part of the SBZ, Stichting down, and mountain biking. Occasio- Charlie the Unicorn, Master Movies or standard questions, so that those are out which is probably one of the reasons Borrelbeheer Zilverling. This means I As an alleged “oude lul”, the choice to nally you will find me training my liver some frustrating bureaucratic facts. This of the way. First of all: yes, my favorite I decided to continue being active in am responsible for a lot in and around become an administrator and thereby at the Abscint, an activity in which you concludes my introduction, and as Ein- color is (of course) PMS185C. Before Scintilla. At the end of the first year, I the bars in the Educafe. My task there board member of Scintilla was (maybe) may always accompany me. stein once said: “The difference between I joined E.T.S.V. Scintilla it already was decided that I really liked the Kick-In is purchasing the drinks, beer, cleaning disputed, and not the least by myself. As you can read, the material I am stupidity and genius is that genius has red, so it just became more specific. the year before and that I wanted to be supplies, etc. But, since Scintilla has been great to be writing about is not that interesting, its limits.”

year 34 year 34 27 26 edition 1 edition 1 greenteam greenteam

The new challenge: London 2016 Setting course for a SHELL ECO-MARATHON This will definitely be necessary, since EUROPE 2016 the Shell Eco Marathon Europe 2016 LONDON TRACK MAP

will be held in London, and the new CARPENTER ROAD

track will feature tighter corners and Track Length: 2240 m LONDON 8 laps: 17.9 km in 43 minutes max AQUATICS START LANE steeper inclines than previous tracks. CENTRE hydrogen-powered General track width: 7. 5 m Furthermore, there is a raised viaduct PADDOCK S F leading up to the paddock. This means Track width at these 2 points: 6.2m T TECHNICAL that not only things like the suspension INSPECTION and steering will need to be improved, victory in 2016 but the electrical systems need to be more efficient as well. FINISH LANE CARPENTER ROAD The new car: H2.Zero

So, the development of a car that is up OLYMPIC STADIUM to these challenges has begun. This car Green Team Twente is a student team which develops and builds a will be the younger brother of the last The London track map fuel-efficient hydrogen car. They have been competing in the Shell car: the H2Zero. It will be an improved Eco Marathon since 2011. The first race was a great success, and the design based on the last car, however, 96%. The goal of this year is to make a No more excuses team went home with the first prize. Since then the competition has it will be lighter, faster, more powerful, reliable boost converter which has an As shown in the last two years, system efficiency of 98.5%. To achieve an effi- reliability is quite important when at- ramped up rapidly, forcing the students to push the limits of inno- ciency this high, without compromising tempting to set records. It is about time vation. reliability, the boost converter will use a for Green Team Twente to set a good custom made solution, controlled by an attempt for first place. The H2.Zero Starting point for 2016 The new team FPGA instead of an IC. will be our new platform which will Pushing these boundaries can lead to dif- Shell Eco Marathon for two years in a row. Stepping up to the challenge is a group Furthermore, the motor controller will hopefully be able to achieve first place ficult problems, especially with regards to The goal for this year is to build on the know- of 16 students. The team consists of five also be redesigned, since there were in London. The team is determined to system reliability. This has cost the team, ledge of previous years to make a more robust electrical engineers, four mechanical en- problems last year which caused the actually complete an attempt; no more due to technical difficulties (and some- system, whilst still innovating enough to stay gineers, three industrial designers, a che- more reliable and more efficient. GaNFETs in the H bridge to short. excuses. times just a little too much bad luck), the ahead of the competition in terms of fuel mical engineer, an advanced technology One of the systems that will be impro- Eventually, a working motorcontroller Green Team Twente is a project chance to complete any attempt at the efficiency. student, a creative technology student, ved this year is the capacitor bank that is was made using an off-the-shelf solution where you can step up to challenges and an international business administra- used to buffer the energy from the fuel from Maxon Motor. The goal this year not only of technical nature, but also tion student. This list quite clearly illus- cell, which enables us to use more po- is to give the GaN approach another related to management and public trates the multidisciplinary approach of wer in the motors, without drawing too try, and achieve an efficiency of around relations. Are you interested in wor- green team. This approach not only helps much current from the fuel cell. Because 99.5%. This motorcontroller will also king in a project like this, or are you bring in a great deal of knowledge, but of the higher viaduct in the track this enable the car to apply regenerative bra- just interested in the developments also expands Green Team Twente into a buffer will be very important, as it needs king. This can be of great significance re- of the team? Like us on facebook university-wide effort. to store enough energy to get to the top garding the overall efficiency, since the (facebook.com/greenteamtwente) The team will also work together with the of the hill. Therefore, the capacitance of track features tight corners in combina- or look at our site (greenteamtwente.nl) members of the previous team to trans- the buffer is upgraded from 17.5 Farad tion with steep descents, where decele- for more information. fer previously gained knowledge, and to 35 Farad. rating is necessary to prevent crashing. ensure previous mistakes will not be The Boost converter that is used to The H2.Zero will also feature an all-new repeated. charge the buffer will also be completely lighting system, new rims, a more light- revised. The boost converter that was weight carbon body, and a gullwing-like designed last year had pretty poor reli- door design. More on the design of the ability, and one revision even caught fire new car will be revealed at the design during testing. This forced the team to presentation, and at the car presentation implement the system designed in 2013, the H2Zero will be shown to the public Team photo of the 2016 Green Team which only has an efficiency of around for the first time.

year 34 year 34 29 28 edition 1 edition 1 lustrum lustrum Lustrumactivities 50th Dies Celebrating our past into the future: To infinity! As many of you know, the birthday of Scintilla is 9 September 1965. That is quite a while ago and a very special while: already 50 years! Of course, such a happy occasion could not have passed without some memorable events, which includes the birthday itself. Hereby I would like to tell you a bit about this event, which had quite some As many of you know (or don’t know, and from now on will never memorable moments for me. forget), Scintilla was founded on the 9th of September. In a time Of course, such an event needed some finished, both boards went to the facul- before any significant digital computing was possible, the ground- preparation. As one of the members of ty club to have dinner. There, we had a work of a flourishing association was born. the board, which organized the event, nice meal, some more alcohol and a nice I helped with the organization quite a talk about the time back when the uni- lot. We played a lot of birthday music versity and Scintilla were just founded. Now, 50 years later, it is a great time companies presenting how they contri- during the day, got lots of decorations During this talk we found out that a to reflect upon the past and to look bute to the world, which was the theme for the event and for the Scintilla Room, lot had changed over time, but also a forward to the future. This, however, for our entire lustrum. and bought a lot of other things neces- lot had stayed the same. Back then, the sounds way too civilized and is quite Needless to say it was a very busy but re- sary for a successful birthday. members of Scintilla were also very fond opposed to what electrical engineering warding month. Everybody had loads of of the taste of Grolsch and also held a students would rather do. We therefore fun, while also some additional acquired One of the most important parts of a lot of activities for members of Scintilla. decided that it would be best to keep skills and knowledge were not passed by. birthday is of course the cake, and so the first board hold a speech, followed A lot of experiences were shared, about the ‘thought pondering’ to a minimum In the following pages some of the acti- we decided that this would not be a by the toast of Scintilla and the first the fun activities each of us had and and do what we do best: have an aweso- vities will be recaptured in some more good birthday without at least multiple board cutting the special cake. about the people we studied with. me time together! detail, to once more relive the 50 years cakes. In total, we had 15 cakes. During Unfortunately, by this time all the plates After the dinner, the first board unfortu- Scintilla therefore declared the period existence of our wondrous association! the event, even though we thought this were already used. Luckily, as true engi- nately had to go home, but we returned between the 9th of September till the was an adequate amount, we barely ma- neers, we immediately found a solution to the Abscint to continue celebrating 9th of October to be a month of cele- naged to let every member present have and repurposed boxes of the cakes as this special day. However, by that time brating. This month we organized loads their own piece. Luckily, by estimating extra plates. Fortunately, by this time the members that were present during of activities that would let a smile ap- how many people were there and were only the special cake was left and so the the event were also hungry and the ac- pear upon the face of any electrical engi- yet to come, we got everyone their own cake was cut and eaten without much tivity was almost over. With the last few neering student. Activities ranging from piece and divided all the cakes, without trouble. members we finished this celebration making the pieces too small. However, Obviously, while eating cake is always and then went on to prepare for the next of those 15 cakes, one was quite special: nice, it is not enough to fill your sto- activities during the lustrum. the glazing on top of the cake was, quite mach for an entire evening. Since the well made, Scintilla’s logo and a congra- first board had to go back to their homes tulations with our 10th Lustrum. later that evening, we invited them to Kind regards, This special cake was of course held back have dinner with us at the faculty club. for an even more special event during After promising the members present at Nick te Velde the evening. During the preparation of the borrel to come back after dinner was Commissioner of Internal Affairs the event, we heard some interesting eating pie on the actual Dies Natalis, to news: the first board of E.T.S.V. Scintilla ‘how to tie your bow tie’. wanted to join us on the dies of the asso- ciation they founded! We immediately There was a camp organized and a reu- responded that we would be honored. nion day for former electrical enginee- Since we did not want our members to ring students. Also a symposium was miss such important people, we decided organized with the subject the subject it would be fun to let our current presi- ‘To Infinity’, featuring no less than 7 dent and one of the present members of

year 34 year 34 31 30 edition 1 edition 1 lustrum

An evening never to forget…

Once upon a time there was a little girl. This little girl lived in the east of a beautiful country. And the little girl had a dream. It was something she had seen in different places, but not yet in her hometown. Luckily for the little girl she met another little girl with the same dream. They talked about their dream, but it did not yet seem to be possible to fulfil their dream.

A few years later the hometown of the up to all the wishes of the girls and needs evening went by very quickly. There two girls was celebrating their 50th of the town. The girls had multiple con- was a photographer and a dinner buffet. anniversary. This was going to be cele- versations with the manager of the loca- People were laughing, talking, eating, brated in the biggest, most festive way tion to plan the grand gala. So the date taking pictures together and enjoying the city had ever seen. So when the city and the location were set, all the plans themselves. Unfortunately it could not was looking for people who wanted to were there. There was only one thing left last forever and the magic of the fairy organise these festivities, both girls de- for the girls. And that was making sure tale like night was over at midnight. For cided to join. Together they were with that the gala was all the town could talk some people the rest of the night was ten boys and girls who were going to about and letting everybody join. spend dreaming about the wonderful organize the parties and celebrations. So the girls started promoting the event. evening, some other people continued And for the two girls, this was the per- They made sure that everybody knew in the city’s bars for a little bit longer. fect opportunity to make their dream about it and would get an invitation. Not willing to let the magic go just jet. come true. Their dream was to organize Most people were really enthusiastic It was a wonderful evening and I (and a grand gala for all the members of the about the gala, and as always a few peo- judging by the overload of positive re- city. ple needed some more persuasion. But actions and happy faces) and everyone The rest of the committee still needed the girls did not let it get to them. And else enjoyed it tremendously. It was re- a little bit more of convincing. The last in the end their enthusiasm worked and ally a dream for me to have a gala with time there was a gala in the city it was a larger part of the city’s inhabitants our beautiful association Scintilla. It not really a great success. But the girls joined the gala to make it a night to ne- brought making the impossible pos- were determined that their gala would ver forget. sible to a whole new level and as I may be a great success, that they would make And after almost a year of preparations, say, with great success. I think Vera, it a success. So eventually the commit- the big night was there. The night of Lynn, Tara, Karin and myself put toge- tee was convinced and the gala became the gala, the last night of the celebrati- ther a perfect finale of the lustrum and a part of the festivities. But it would not ons. One more event to make a success. we proved that Scintilla and a gala can be just one the festivities, it would be It would become a night to never for- definitely be a match made in heaven. the grand closure. So the pressure was get for the people of the town. And of Thinking back is still making me smile on for the two girls to make it a great course a night for everyone to dress up and I’m sure it will take some time be- success. in their most fancy clothes. It was an ex- fore I forget the 9th of October 2015. But these girls were not crazy, it would cellent chance for the girls to plan a girls- I hope everybody enjoyed themselves be a lot of work for just two persons. afternoon full of dressing up, doing hair and thank you for coming. All our hard But luckily for them they knew that and make-up and getting excited for the work would have gone wasted if you there were three other girls that would evening. All dolled up they went to the would not have come and made the want to help. So the five of them sat to- location ‘The Jaargetijden’ at the start of evening the success that it was! So, if gether and started making plans. They the evening. They had a preview of the you wasn’t there, (poor you) you now wanted everyone to come and make it location that was all dressed up accor- know, next time, you definitely want to lovely for everyone. So the search for a ding to the infinity theme and looking be there! location begun. The whole region was very pretty. searched. All possible locations were From seven in the evening the guests Love, considered and contacted. In the end started arriving and they were welco- The gala committee the girls found a location that measured med with a Scroppino. The rest of the By Dieuwertje ten Berg

year 34 32 edition 1 on location What is this? it’s smaller!

Yes, that is correct, from this point on the Vonk will be smaller. No longer the big A4 Vonk of which you never know where you should keep it. Now this problem will be gone, because now there is a nice, beautiful and fancy-looking (semi-)B5 format Vonk. How and why DeVonk did this happen, and what do we do with this?

At Gildeprint Obviously, the first step in creating a pages, four aluminium plates need to be book, magazine, or anything else that printed for the four colours the prin- As Vonk was discussing our now revea- requires a press is to receive an order for ter uses: cyan, magenta, yellow and key led new format, we were invited to learn one from a customer. The company helps (CMYK). If needed, an additional plate the process of how Scintilla’s favourite the customer in their choices and has a can be added for a glossy layer. These magazine travels from our hard disk to large collection of books and magazines plates go into a second machine, an off- your doormat. A tour was given by none in all shapes and sizes to give the custo- set printer, which consists of five towers; other than Freddie Drijsen, the account mer an idea of what their final product four for the four colours (CMYK) and manager of printing office “Gildeprint will look like. After the first step, two one extra for the glossy layer. On the si- Drukkerijen”. After a warm welcome ways of printing can be chosen. des of the printed papers, calibration co- with tea and coffee, a first look was ta- lours are printed. These colours are there ken at the communications part of the The first method is the older one of the to find out whether the right amounts of company. two. Aluminium plates are printed, each ink are used. The allowed difference in large enough to fit 4 pages. For every four colour intensity is as low as 0.05%. The print also contains registration marks, which are able to show whether a plate is not slightly turned or tilted. If the re- gistration marks of one of the four or five plates does not overlap, one of the plates must have been inserted incorrectly. This method has a high quality, but is a long- winded process. Usually this process is used for small orders, such as magazines ranging from 10 to 1000 copies.

The second way of printing is with the use of a digital printer. Gildeprint has two digital printers; a bigger one and a smaller one. A digital printer has a va- lue of about half a million euros. These digital printers are able to produce 200

year 34 edition 1 33 on location

some day there is a rip-out page within the Vonk, just because we can now. The more technical changes are the lay- out changes. Since we went from A4 to (semi-)B5, we had to adjust some layout features, such as borders, marges and font size. Since we do not want to deli- ver a magnifying glass with every Vonk we produce, the font size could not just be scaled along with the measurements, so they needed to be adjusted. We also did not want it to be that big that the amount of information on a page would become smaller, such that articles would need more pages. Because we all know that if an article looks to long, some people might get scared, even though the amount of text would be the same. We also moved the marges around a bit sheets an hour, with a sheet containing the pages need to dry for four hours be- and shifted with some standard layout 4 pages on both sides. This, in compari- fore going to the next step. Gildeprint features like our page numbers and the has many extra machines of which all nice-looking Scintilla-squiggle. have their own purpose. Whether it is la- minating, packing or cutting; everything More information? is possible. Changes This new format could not have been possible without the help of Gildeprint Drukkerijen. You can visit their web- site www.gildeprint.nl or take a look on www.promoveren.nl, where they offer 30 years of experience and help with the son to the offset printer which is able to layout and production of your thesis. If produce Vonks for everyone in Scintilla you are interested in the process of prin- in a mere 1.5 days, is a much better op- ting and want to see it with your own tion for larger assignments. For example, eyes, then go quickly to their YouTube the Moteq notebooks have been printed channel. A quick search for Gildeprint using this machine. So what changed for us? With this new Drukkerijen should do the trick. method of printing, it is made possible After these two machines, the last op- for us to make more choices. For instan- The Vonk editor team hopes you enjoy tional steps are taken. Most orders are ce, we could use glossy covers; use dif- this new format and wishes you lots books, notebooks or magazines, which ferent kind of papers and even have less of fun reading this new edition of the means that the large amount of printed care about the amount of papers we use. Vonk . pages need to be put into the right or- It also happens to be cheaper to have this der and stuck together. This can be done cooler looking Vonk. Due to the new via stapling, sewing or gluing. Only the way of printing, which is slightly compa- latter two are done at Gildeprint. The rable with printing as we do on printers sewing is done in one quick action with like Zirma, it goes a lot quicker and ea- a large sewing machine, while gluing the sier. Some of the possibilities we gained pages is done with a substance called were already named before, but there is ‘pur’. This method is the easiest and one more. We cannot show all the possibi- of the cheaper options, but it means that lities in one go, but it might occur that

year 34 34 edition 1 junction Junction

Mark Bentum is the director of Electrical Engineering, and a tea- cher at the university. On the 17th of December He was intervie- wed by the Vonk, about his life as a student, and his experiences with the university as a student, and later on as a teacher / director of Electrical Engineering.

Where and what did you Did you immediately start study? your master when coming I studied Electrical Engineering at the to the UT? HTS (Hoge Technische School) in Back then there was no bachelor master look forJunction nodules. These nodules can be Groningen which was a four year study. system. When finishing the HTS one spotted on an x-ray, but from here it can After that I started to study Electrical could just start to get his propedeuse, not be determined if the nodule is can- Engineering at the university of Twente, and afterwards his PhD. I did not have cerous or not. It is perfectly possible for here I studied the course medical signal to get the propedeuse except for a few these nodules to be just calcified mate- processing which took me three years to subjects. After that I went for my PhD rial, which is not cancerous, this is just finish. After I had finished my study I in the field of signal processing. I did a thing that happens in the lungs. So we started to work at Astron. this in the area of the medical signal made two pictures instead of one, at the processing. same time. So then we had a film. We Why did you study Electri- placed a nonlinear material and then Did you have an intern- made another film. After which we had cal Engineering? two pictures with two unknowns, the I already made this choice early on. ship? two unknowns in this case are the cal- When I was young, I met a group of Yes, at the HTS I did my internship at cium, and the soft tissue, so the harmful radio-amateurs. This group was part Philips data systems in Hilversum, at tissue and the harmless tissue respect- of the organizers of a camp I went to. Philips in Hoogeveen, and at the Dutch fully. With these two pictures we could I liked what they did there and wanted cable manufacturer NFK in Delfzijl. Be- solve the equation with two unknowns. to learn more about it. Then there was cause I already did my internships at the This way we could make a picture of this one time where we were going to HTS I did not have to do them at the the lungs, where these nodules could make a radio, back then I was like twelve UT, but because I found that I lacked be seen and in which of the two catego- years old, and we made this radio using foreign experience, I did my PhD assig- ries the nodules belonged. When it was a germanium diode, this way we could nment in America. soft tissue the doctors could do tests to receive some high frequency signals, determine if it was really cancerous or without using much voltage. Because What did you do for your not. So this is what I developed, tested, this peaked my interest I went on to and build in the hospital. We then made make my own transmitters, and so when PhD assignment? photos of people who had lung cancer, it was time to choose a study I chose EE. In America I worked on a medical sys- and eventually that was the system. Our I first went to the HTS because I came tem to be used in hospitals. When a trip was sponsored by Philips medical from the HAVO, and because this went lung photo is made, a photo is made systems, who later used the product we easy I went to the university afterwards. from the chest and on this photo they made.

year 34 edition 1 35 junction junction

How were you as a stu- forgotten it, now you have everything dent? together. I also think it motivates stu- dents to work, as you get everything or I was a student who did many things be- nothing. If you pass the module, you get sides my study. I was a student for three 15EC, but if you fail just one subject, years here at the university, in that time you get nothing. It used to be the case I participated in sports like: ice-hockey, that you had about 4 or 5 subjects, and table tennis, and rowing. Besides that I if you wanted to do something else next also was a teacher’s assistant. I guided to your studies it was no problem to the subjects of Electronics, and non- drop a subject. Nowadays that is just im- linear Electronics for a few years. Besi- possible. The government requires that des that I did not have much time left to 70% of everyone who re-enrolls for the do other side activities. So I have always second year finishes his or her bachelor been active, in the sport associations, in a total of 4 years. That percentage and as a teacher’s assistant. used to be 15% before TOM. We got a yellow card from the visitation commit- tee because of that, so something had to change. TOM and also the BSA helps us reaching 70%. Students are working Telescopes at Westerbork harder because of those two things, and I think that is a good thing. find out what you like most. work at ASTRON in Dwingeloo. AS- TRON is the organization that manages Marinus Jan Bentum Are there differences If you could change any- the large radio telescope by Westerbork. between the original idea thing in the current system, I worked there for over 10 years. After for TOM and the way it is what would that be? executed now? What subjects do you If I want to change something, I just Age 48 teach? Not really. I was in the curriculum com- do that, as I am the program director. mittee when TOM was created. We I am continually working on impro- I teach in the bachelor phase: commu- designed the first two years of the ba- ving the program. But those are mostly nication systems, which is in module 8. chelor, as in those years the basics had to small things, to make the curriculum I am module coordinator of module 12, be taught. In the third year the students more studiable. If a module coordinator Birth place Smilde which is the bachelor thesis. have more freedom: they do their mi- thinks something should be removed In the master phase I teach: modern from a module or something is missing, a while I wanted to start teaching again communication systems, mobile radio I started looking into that. I think that and have contact with students. I always communication, and smart antennas if you spend a lot of time designing a remained in contact with the UT, so and propagation. Besides that I am also new curriculum, there will be some mis- when I was asked to create a new chair the director of Electrical Engineering. takes and those have to be corrected, but by the UT, I did that. So since 2008 or Favorite Red other than that I think the new curricu- 2009 I’m working here. lum should just be studied for a while. Color What do you think about So there are constant changes, but they the Twents Education Mo- are nowhere near as big as the introduc- What do you think of tea- del? nor and their graduation projects. You tion of TOM. ching at the UT? I do believe in the Twents Education do two graduation projects: a design I really like doing it. I also like experi- Favorite Bok Beer Model. I think it is good that multiple project and a research project. After Did you already know menting with different ways of teaching. Drink subjects get brought together in modu- your education, you also either work as For example, I once gave the subject les. That way you can better see the who- a designer or as a researcher. You can for during your studies you Cosmology. In that course were stu- le picture, instead of having one subject example work at Philips and design the wanted to become a tea- dents from many different studies, like in the first year and then needing that next electronic shaver or invent a new cher at the university? Electrical Engineering, Applied Physics knowledge as prior knowledge for a sub- supersonic localization system, or you and Industrial design, but also psycholo- ject in the third year when you have long can do research. The projects help you No. After I finished university, I went to gy. Psychology students have other prior

year 34 year 34 37 36 edition 1 edition 1 junction

with ASTRON and the TU Delft on OLFAR, the Orbiting Low Frequency Array. The plan is to launch 50 to 100 little satellites in an orbit around the moon, and those satellites together form the array. All these satellites have to communicate with each other and with the earth, and the array itself is one large antenna. My research department researches all these kinds of things. Another subject my research depart- ment works on are sensors in the inter- net of things. There are sensors every- where, and all those sensors have to send their data somewhere. We try to make those transmitters as energy efficient as possible, so every device lasts as long as possible.

Do you have a family at home? Yes, I have a wife and two sons, of 14 and 16 years old.

What are your hobbies?

In my free time I like to drive my 4x4 car off-road, working on my house and I’m still with the scouting.

What do you want to do in OLFAR satellite the future? knowledge than physicists, so the tea- I just want to stay working at the uni- ching had to be adapted to that. I made versity and do research. My dream is groups of people who each had to study that one day I can look at the moon and one aspect of the course, make a talk imagine the OLFAR satellites orbiting about it and then give a lecture about it. around it, and that we can discover the At the university, you have a lot of free- origin of the universe with it. dom in how you teach a subject. The curriculum committee formulates what you have to learn in each module. This Do you have a piece of ad- is called the ‘eindtermen’. The only re- What kind of research do vice for the students? quirement is that the students have the you do? right amount of knowledge at the end of Enjoy your life, do stuff you like. I think the module, but how they acquire that you’re not living your life right if you knowledge is left to the teachers. One Most of the time I am busy with my don’t do what you like. way of teaching students is by giving chair, telecommunication engineering. lectures, but you could also use problem Personally, I work on radio systems based learning, like in module 4. for many different applications. For example, at the moment I’m working

year 34 38 edition 1 solarteam Red One Go

“Probleem? Poar Neem’n, Red One Go!” The whole team is yelling and partying in the fountain in Adelaide. We made it, 3000 kilome- ters through the Australian outback, a unique experience. Proud of our performance during the race, all we could do was smile.

Amazing Australia Get back to work in Darwin In September we arrived in Darwin, one better tracking the maximum power month before the race. Why so early? To points of single solar cells. This is done be able to test our car in the Australian When the car arrived, we had to focus by balancing the output current of solar conditions, to acclimate to the weather again and the hard work began. We had cells, instead of using the traditional by- and to finalize the Red One. During our to finalize the solar panel and SABINE pass diodes which dissipate the energy. time in Darwin we stayed in a scout hall, The Australian sun gave us the opportu- a big room filled with stretchers. Our nity to characterize our solar array and workshop was located at the Charles measure the benefits of SABINE. We Darwin University, only a few hundred also had to test whether we reached our meters from the scout hall. The trans- temperature limits, especially the battery port box with the Solar Car had a few pack and MPPTs can become very hot. days delay, which gave us the opportu- (Solar Array Balancing Interface Not nity to discover Darwin; visit national Expected). SABINE is one of our elec- Check, check, double parks, watch crocodiles and barbecue on trical improvements of this edition. It the beach. increases the solar arrays’ efficiency by check!

We were allowed to test our car on the Australian road for about two weeks. Before you are able to drive on the pu- blic road, the Australian road authorities have to issue a roadworthiness certificate. They check your belts, horn and lights, for example. After the testing period, our car had to go through the scrutineering. During the scrutineering, the organiza- tion checks whether your car meets all the regulations. We also had to hand in documentation with the schematics of the electrical system. During the scruti- neering itself, the organization focuses especially on the battery pack and the solar array. A seal was being placed inside the battery pack, which we were allowed Control stop to remove at the end of the race. This, to

year 33 edition 1 39 solarteam

our achievements and the exciting race we drove. Time for party and holiday! At the moment of writing, my holiday has finished and we are working on the completion of the project. I had an ama- zing time in Australia, preparing and driving the race and a nice holiday after- wards. Together with two teammates, I drove in a campervan from Adelaide to Cairns in five weeks. We have seen and done a lot of crazy things. During this last month we work out the possible improvements for the electrical design of our solar car. Improvements on the current systems, such as motor effici- ency and the SABINE project, but also Service car some new ideas/projects came up. make sure the teams do not change cells mizing the car performance. We were inside the battery pack, for energy gains. standby to fix problems, which could Become a Solar Team I found it more symbolic, because no occur during the race. Besides this, we team will break those rules. were responsible to run the control stops Twente team member and the charging in the morning and yourself! Ready, set, Red One evening. We customized our service car to fit in all the service-boxes, for quick Do you have ideas for improving our GO! service possibilities. About one hour be- solar car? Do you want to have a more fore the control stop, we started driving practical year? Do you want to be part The qualification took place in combina- forward, to prepare the stop. At control of a highly motivated engineering team? tion with the dynamic scrutineering on stops the solar car has to wait for 30 mi- Do you want to participate in a World Hidden Valley. The team with the fastest nutes. The solar panel is reconfigured to- round time starts first at the beginning wards the sun for higher energy gain. We of the race. A high qualification does spray the solar panel with demineralized not only result in a time advantage at the water to clean the dust and increase the beginning, it also reduces the amount performance. Watch out, before you cau- of cars you have to overtake. Overta- se shadow on the panel. After the 30 mi- king is not that easy, especially when the nutes the solar car leaves. After this, we road becomes single way. We qualified had to clean up the place and drive back into the convoy. With the high speed of this year, the service cars had to drive speed limit to arrive at the next stop in Championship? Watch our after movie, time. At 5 o’clock we finished for the day to get a feeling of the outback experi- and set up our camp in the outback. ence. Are you interested in Solar Team Twen- The end of an ama- te? Don’t hesitate and apply for the new edition of Solar Team Twente, which twelfth, in the same range as our main zing challenge will start around September 2016 and competitors in the Challenger Class. participate in the World Solar Challenge During the race I was part of the service After four and a half day the rush of the 2017.For more information about Solar team and together with Robin Lohuis, race ends and we finish in Adelaide, only Team Twente 2017, contact sollicita- Elmar Peters and Tom Vocke, we drove a few minutes after the number one. [email protected] the Electrical service car. The service Traditionally we make our way towards team is responsible for Red One during the Adelaide fountain and take our first Being part of Solar Team Twente, an ex- the race and has only one focus; opti- ‘shower’ in four days. We are proud of perience to never forget.

year 33 40 edition 1 column Impressions of a freshman

At the moment I wrote this down, I could declare myself a student for three months and six days. Thinking by myself, this is a long time and although I know that the road ahead is far longer, I still remember how the road started.

Coming from Enschede, the terrain of ficult quickly. For a subject like math I the university was already well-known knew already everything, because I had to me. Still, seeing all those people who had the subject before. I even won a all came here was overwhelming, but price for answering most quiz questions ter that it wasn’t there, because just like also exciting. correctly. This however changed when gala’s, I have no experience with dan- starting with the next topic, which was cing. Still it was a night to remember. in the beginning not too difficult, but The best improvement from going to over time got tough so I had to start the university is the people, and alt- practicing. The subject I liked most, hough I liked my high school class, the and still think is the best of all subjects, group I’m now in is far more enjoyable. is the laboratory. Working in groups of two on a small experiment, you feel like a real scientist, although the outcome I was even getting more excited when I is predetermined. I’m very lucky with met the first two people. Their names my lab partner, who is someone who are not known to me and after that already knew a lot about Electrical En- moment, we never met again. The only gineering before starting with this study. thing I still remember is that they were Although he’s is not that punctual, with in the same class as my cousin. his knowledge and me being present we They are people that think in the same When later being added to the group of made every lab journal a piece of art. way as me, and not only here in college, students of Electrical engineering, they Luckily, life is not only work. There are but also outside college with the Chris- were all people I hadn’t spoken to be- also lots of other things, like the eating tian student association Alpha. There fore. Still, these are the people I eat with on Wednesday mentioned before, Scin- you are with people of all educations. every Wednesday. tilla also organizes activities which are This takes a lot of your time, but it is Shortly after the Kick-In, the first les- really fun. An example is the Lustrum worth it. sons started. Telling about the first les- gala, which was the first real gala I’ve If I would give any advice to anyone, sons and the impression would fit great been to. Sitting at one of the most fa- it is to join also some kind of sport or over here, if I was there. Starting the first mous places in Enschede, de Jaargetij- other kind of group with activities next day without the right timetable doesn’t den, we could enjoy food and drinks for to scintilla. When I finished writing this leave a good impression, but after that free, as long as you had paid. The only down, I could declare myself a student I have almost always been on time. The thing I missed was a dancefloor to do for three months and seven days, be- first lessons were easy, but got more dif- some ballroom dancing. Maybe it’s bet- cause being a student takes a lot of time.

year 34 edition 1 41 column What next?

“Hey, long time no see! How are you doing?” “You good, you?” “Yeah, also good, how’s study going, almost done?” “Yeah, I’m writing my master thesis at the moment. Oh nice, what do you want to do after graduation?”

The conversation above is a conversa- would want to travel the world, but that guess, that didn’t happen. And now tion that, in some kind of form, keep’s won’t pay for itself. during the last stage of my studies, I am occurring the last couple of weeks/ But maybe I’m interpreting the questi- again supposed to know what I want. months. When people hear that I’m on wrong, maybe people want to know And I still do not know. busy with my final project the next ques- what kind of work I want to do. What To all the people who always have tion is always ‘what do you want to do kind of company or type of job. But how known what they wanted to do in life, next?’ The other option is them asking am I supposed to know that? how do you know that? What made you when will you be finished (like that’s a Apparently at certain times in life you so sure? Why not something else? May- fixed date that does not move around – are supposed to know what you want in be it is just not for everyone to know it hell no, that’d be easy). life. As a child, adults ask what you want like that. Or perhaps everybody knows to be when you grow up. My answers it at some point during their life. Until than ranged from hairdresser, to dentist I hear an answer that will help me, I’ll and a violinmaker (yes, really, I wanted just keep experiencing and perhaps that to be a violinmaker when I was a child). lightbulb will magically go on. And if it Then again in high school, you have to doesn’t, that’s okay. I’ll follow the wis- decide what you want to study. Some dom of the Aussies and the kiwi’s; no people already knew this since they worries. Because knowing everything were 12. I really had no clue. When I won’t make me happy either. The point is, I do not know what I want was freshman in high school, those seni- to do next. How am I supposed to know ors always looked so grown up and they Dieuwertje what I want to do next? So the general must know what they wanted in life. answer that I give is that I want to find a job. And people nod understandingly. There are a few things I don’t under- stand about the question. People always ask it in a way like you have a wide arran- ge of choices. Which I do not really see, because after six year of studying there is this thing called a study debt that wants to get paid. And because of that, I want A part of me always kept hoping that I to get paid. But in order to get paid, one would magically know what I wanted must have a job. So what are my options when I would become a senior. Like a other than finding a job? Of course I lightbulb that would go on. You might

year 34 42 edition 1 puuzle Puuzle

During the last edition nobody answered all the questions in full or correctly. Therefore the prize goes to the one who was closest to the correct answers, congratulations Rik de Sain! For this edition Truusje has some problems for you to ponder on. The first person to help her find the answers to the following 9 puzzles will be rewarded with a home baked pie! Mail your ans- wers to [email protected].

A chip designer, specialized in routing, wants to layout a chip consisting of eight individual modules. The surface that is available on the chip is L sha- ped like in the figure below. He wants to divide the available space into eight Five electrical engineers have acquired sections of identical shape and size. Un- government funds of €20,000 for their fortunately he was not taught how to research. To divide this money they do so during his masters degree, can you decided on the following system: The help him out? engineers get to make a proposal for the division one by one, starting with the oldest and ending with the youngest. Truusje is feeling generous and wants If a proposal is accepted by at least 50% to give away 45 Xilinx FPGA’s to three of the engineers, the proposal is passed. electrical engineering students. She pro- Elsewise the engineer who made the mised 1/2 of the FPGA’s to the first stu- proposal is brutally electrocuted. All li- dent, 1/4 to the second student, and 1/6 ving engineers are allowed to vote, and to the third student. She then called Mr all engineers will try to get the largest Mu for advice, after thinking a while he possible funds, without moral objecti- came with a solution, and as thanks she ons. gave mr Mu 1 FPGA’, what was mr Mu’s solution ? The question: Which division should the oldest engineer propose, in order to get most funds, and stay alive.

year 33 edition 1 43 To create something you never had, start with something you never did

Omron invests in enthusiastic and ambitious students. There are special opportunities for academics to work on challenging and interesting internship or graduation projects both at home and abroad. And with positions in electronics, product development, sales, manufacturing or product marketing, there are always relevant technical jobs that match your background.

Are you curious and do you want to create something? Are you studying Electronics or Industrial Engineering, Applied Physics, Mechanical Engineering, Mathematics or Computer Science?

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