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Faculty of Mechanical Engineering.

Electrochemistry as the Holy Grail

Just imagine, an industrial estate with sterile factories that don’t emit clouds of smoke and strange smells, and which ‘run’ entirely on electricity. Ruud Kortlever, university lecturer at TU Delft’s Department of Process & Energy, believes this is feasible, namely by introducing electrochemical systems in chemistry.

Bicycle research has overcome scepticism

He has a reputation as the leading researcher on bikes, a topic that elicits a certain level of scepticism in academic circles. Despite this, the research has been undeniably productive, not only in terms of fundamental knowledge, but also practically. For example, last year saw the launch of the steer-assist system as a way of combating the increasing number of accidents involving cyclists. I ended up conducting bicycle research more or less by accident. I started to study mechanical engineering at the technical college (HTS) in Dordrecht and simply loved it. I’m still nostalgic about that atmosphere of nuts and bolts and tinkering with things. As a child, I always wished my father had a car scrapyard...” “After the HTS I went to the predecessor of TU Delft and did my doctorate quite late. But I’ve always kept that fascination. A company like Hoogovens, with its iron and steel, warms the cockles of my heart. But, in the early days, I certainly wasn’t hankering to conduct research into bikes.” Cornell ““The bikes only became part of the picture when I took a sabbatical in around 2001. I went to Cornell University in the US, where I met the researcher Andy Ruina. He was working on robots and biomechanics, just like me. We immediately clicked. At the time, he needed to submit a research proposal to the National Science Foundation and asked me if I would look into what scientific research had been done on bikes. It turned out there’d been a lot, but the knowledge was quite fragmented. This made me realise what huge opportunities there were for interesting research. That was back in 2002. And it hasn’t actually stopped since then….” Science When he returned to TU Delft, Schwab’s new-found fascination for bikes led to the establishment of the (now acclaimed) TU Delft Cycling Lab. Later, there was even a publication in the prestigious journal Science. “That was quite a milestone for my specialisation.” Schwab and Jodi Kooijman (along with Ruina, Jim Papadopoulos and Jaap Meijaard) then turned their attention to writing an article on the question: why is a bicycle stable when travelling above a certain speed? A bicycle travelling at speed can be given a serious shove without it falling over. It was always thought that stability was strongly associated with two factors. Firstly, the gyroscopic effects of the spinning wheels would cause stability. Secondly, it was thought that the “trail” factor played a significant role. Trail is the degree in which the front wheel follows the steering axis. The publication of the TU Delft article in Science put an end to that old idea once and for all. Gyroscopic effects and trail can contribute to stability but are not necessary for it. This has not only been proven theoretically but experimentally as well. Nothing new As indicated earlier, this was a milestone. But bicycle designers continued to apply the old concepts, even though they were shown to be wrong. Nothing had essentially changed in basic bicycle design for almost a century. “At that time, we developed a mathematical model with some 25 physical parameters that successfully predicted the stability of a bicycle design at various speeds. We also experimentally proved that the insights behind the theory were correct.” “The model we developed will enable manufacturers to work specifically on the stability and steering of their bicycles. That could prove interesting for all kinds of bikes.” The Delft student team HPT’s high-speed bike, which briefly held the women’s world speed record last year, also benefited from the fundamental knowledge acquired. Steer assist The same also applies to conventional bikes. For example, recent years have seen the launch of the steer-assist bike. TU Delft and the bicycle manufacturer Gazelle have developed a prototype of a bike with smart steering assistance that may help to reduce the number of falls with bicycles. Schwab sees this as a necessary move. “The number of accidents involving bicycles is on the rise: it grew by around 30% from 2000 to 2010. Serious bike accidents are often the result of the cyclist losing control of their bicycle, and in many cases the victim is an elderly person. Every year, some 120 cyclists of 55 years and older are killed in an accident, while more than 4,000 cyclists over 55 are involved in a serious accident.” Simple “This is why we developed a prototype of an electric bike with steering assistance. This steer-assist system is the first system in the world that can keep a bicycle upright. It does this with a motor installed in the steering column that adjusts the steering if the bicycle threatens to fall over. This system keeps the bike and its rider stable at speeds above 4 km/h,” says Schwab. “It’s actually technically quite simple. “There’s a sensor that detects when the bike is falling over, a motor and a processor to control the motor. The hardest part is finding the right algorithms for the processor, which was where our scientific research into bicycle stability proved enormously important.” Further development “We’re now working with Gazelle on further tests and development. Considerable research is still needed before the steer-assist system can be made available to consumers. The prototype is currently being used to test users’ experience of the steer-assist system and to find out what kind of assistance works best. “We now want to study what kind of assistance is appreciated by the cyclist and when.” “This latter aspect, the human factor, is increasingly reflected in our research. It is shifting from fundamental bicycle research towards human and machine interaction. In that area, there is still a lot of work to be done. For example, we still don’t know exactly how we actually steer a bike. Another very important factor is user acceptance of technological innovations. What exactly do users appreciate and how far do they want to allow the influence of technology to reach, for example in the form of steer-assist systems?” Olympic Games Schwab’s field of research is therefore very wide-ranging. Sport has turned out to be an unexpected, but now quite important, part of the research. “This is something I would never myself have considered. But thanks to the Sports Engineering Institute here at TU Delft, that kind of research has been given a real boost.” One of many examples of this is the model TU Delft developed to optimise the team time trial for Team Sunweb during the last Tour de France. Optimising the team time trial is far more complex than the individual time trial because the performance depends on several racers. One of the things involved is switching the positions of the cyclists. Mathematical models allow you to develop the ideal strategy. It’s also important to keep a record of exactly how long a cyclist is at the front, because that has a major influence on how quickly their body’s “battery” runs down. The model works out the times at the front on the basis of details including speed and wattage. “We also looked at track cyclists and their bikes. What struck me immediately is that most bikes for track cyclists are actually too small to transfer power most effectively. Another subject we worked on was bicycle handling, with a particular focus on steering rigidity.” The aim of all of this is to achieve some more great successes for our cyclists at the Olympic Games, later this year in Tokyo. Schwab will definitely be there. Scepticism At the age of 64, with the end of his long TU Delft career looming, Schwab still sees plenty of potential for further research. “The folding bicycle is one example. I don’t know about you, but mine is terrible to ride. I wouldn’t dare ride it no-handed. I would actually be interested in taking a completely new look at the whole basic design of the folding bike, and I feel similarly about the development of cargo bikes.” “I’m a bit of an odd one out in the academic world. There has always been a certain level of scepticism: bicycle research, what has that got to do with science? But the Cycling Lab I initiated in 2002 will certainly continue to exist even if I am no longer working for TU Delft. That’s something of which I’m very proud.” The human factor is increasingly reflected in our research. It is shifting from fundamental bicycle research towards human and machine interaction Arend Schwab +31 15 27 82701 A.L.Schwab@tudelft.nl This is a Portrait of Science from ME I ended up conducting bicycle research more or less by accident. I started to study mechanical engineering at the technical college (HTS) in Dordrecht and simply loved it. I’m still nostalgic about that atmosphere of nuts and bolts and tinkering with things. As a child, I always wished my father had a car scrapyard...” “After the HTS I went to the predecessor of TU Delft and did my doctorate quite late. But I’ve always kept that fascination. A company like Hoogovens, with its iron and steel, warms the cockles of my heart. But, in the early days, I certainly wasn’t hankering to conduct research into bikes.” Cornell ““The bikes only became part of the picture when I took a sabbatical in around 2001. I went to Cornell University in the US, where I met the researcher Andy Ruina. He was working on robots and biomechanics, just like me. We immediately clicked. At the time, he needed to submit a research proposal to the National Science Foundation and asked me if I would look into what scientific research had been done on bikes. It turned out there’d been a lot, but the knowledge was quite fragmented. This made me realise what huge opportunities there were for interesting research. That was back in 2002. And it hasn’t actually stopped since then….” Science When he returned to TU Delft, Schwab’s new-found fascination for bikes led to the establishment of the (now acclaimed) TU Delft Cycling Lab. Later, there was even a publication in the prestigious journal Science. “That was quite a milestone for my specialisation.” Schwab and Jodi Kooijman (along with Ruina, Jim Papadopoulos and Jaap Meijaard) then turned their attention to writing an article on the question: why is a bicycle stable when travelling above a certain speed? A bicycle travelling at speed can be given a serious shove without it falling over. It was always thought that stability was strongly associated with two factors. Firstly, the gyroscopic effects of the spinning wheels would cause stability. Secondly, it was thought that the “trail” factor played a significant role. Trail is the degree in which the front wheel follows the steering axis. The publication of the TU Delft article in Science put an end to that old idea once and for all. Gyroscopic effects and trail can contribute to stability but are not necessary for it. This has not only been proven theoretically but experimentally as well. Nothing new As indicated earlier, this was a milestone. But bicycle designers continued to apply the old concepts, even though they were shown to be wrong. Nothing had essentially changed in basic bicycle design for almost a century. “At that time, we developed a mathematical model with some 25 physical parameters that successfully predicted the stability of a bicycle design at various speeds. We also experimentally proved that the insights behind the theory were correct.” “The model we developed will enable manufacturers to work specifically on the stability and steering of their bicycles. That could prove interesting for all kinds of bikes.” The Delft student team HPT’s high-speed bike, which briefly held the women’s world speed record last year, also benefited from the fundamental knowledge acquired. Steer assist The same also applies to conventional bikes. For example, recent years have seen the launch of the steer-assist bike. TU Delft and the bicycle manufacturer Gazelle have developed a prototype of a bike with smart steering assistance that may help to reduce the number of falls with bicycles. Schwab sees this as a necessary move. “The number of accidents involving bicycles is on the rise: it grew by around 30% from 2000 to 2010. Serious bike accidents are often the result of the cyclist losing control of their bicycle, and in many cases the victim is an elderly person. Every year, some 120 cyclists of 55 years and older are killed in an accident, while more than 4,000 cyclists over 55 are involved in a serious accident.” Simple “This is why we developed a prototype of an electric bike with steering assistance. This steer-assist system is the first system in the world that can keep a bicycle upright. It does this with a motor installed in the steering column that adjusts the steering if the bicycle threatens to fall over. This system keeps the bike and its rider stable at speeds above 4 km/h,” says Schwab. “It’s actually technically quite simple. “There’s a sensor that detects when the bike is falling over, a motor and a processor to control the motor. The hardest part is finding the right algorithms for the processor, which was where our scientific research into bicycle stability proved enormously important.” Further development “We’re now working with Gazelle on further tests and development. Considerable research is still needed before the steer-assist system can be made available to consumers. The prototype is currently being used to test users’ experience of the steer-assist system and to find out what kind of assistance works best. “We now want to study what kind of assistance is appreciated by the cyclist and when.” “This latter aspect, the human factor, is increasingly reflected in our research. It is shifting from fundamental bicycle research towards human and machine interaction. In that area, there is still a lot of work to be done. For example, we still don’t know exactly how we actually steer a bike. Another very important factor is user acceptance of technological innovations. What exactly do users appreciate and how far do they want to allow the influence of technology to reach, for example in the form of steer-assist systems?” Olympic Games Schwab’s field of research is therefore very wide-ranging. Sport has turned out to be an unexpected, but now quite important, part of the research. “This is something I would never myself have considered. But thanks to the Sports Engineering Institute here at TU Delft, that kind of research has been given a real boost.” One of many examples of this is the model TU Delft developed to optimise the team time trial for Team Sunweb during the last Tour de France. Optimising the team time trial is far more complex than the individual time trial because the performance depends on several racers. One of the things involved is switching the positions of the cyclists. Mathematical models allow you to develop the ideal strategy. It’s also important to keep a record of exactly how long a cyclist is at the front, because that has a major influence on how quickly their body’s “battery” runs down. The model works out the times at the front on the basis of details including speed and wattage. “We also looked at track cyclists and their bikes. What struck me immediately is that most bikes for track cyclists are actually too small to transfer power most effectively. Another subject we worked on was bicycle handling, with a particular focus on steering rigidity.” The aim of all of this is to achieve some more great successes for our cyclists at the Olympic Games, later this year in Tokyo. Schwab will definitely be there. Scepticism At the age of 64, with the end of his long TU Delft career looming, Schwab still sees plenty of potential for further research. “The folding bicycle is one example. I don’t know about you, but mine is terrible to ride. I wouldn’t dare ride it no-handed. I would actually be interested in taking a completely new look at the whole basic design of the folding bike, and I feel similarly about the development of cargo bikes.” “I’m a bit of an odd one out in the academic world. There has always been a certain level of scepticism: bicycle research, what has that got to do with science? But the Cycling Lab I initiated in 2002 will certainly continue to exist even if I am no longer working for TU Delft. That’s something of which I’m very proud.” The human factor is increasingly reflected in our research. It is shifting from fundamental bicycle research towards human and machine interaction Arend Schwab +31 15 27 82701 A.L.Schwab@tudelft.nl This is a Portrait of Science from ME Other Portraits of Science The future of architectural glass Avoiding division in climate adaptation

TU Delft accelerating the electrification of the chemical industry

This week, NWO announced that the RELEASE project, lead by prof. dr. ir. Paulien Herder, will recieve funding within the Crossover-programme. The aim of RELEASE is to store sustainable energy, in order to make it available when it is needed. To do that, the consortium will use a multidisciplinary approach which extends from research in the lab to implementation in the field. Strong ambitions The objectives of the international climate agreement in Paris or that of her Dutch sister, the recently presented ‘klimaatakkoord’, are ambitious to say the least. Compared to the 1990 level, greenhouse gas emissions must be reduced by 49% in 2030 and by as much as 95% in 2050. This has significant consequences for our chemical industry. Due to the scale and complexity of the challenge, we have to look far ahead. The chemical processes that this industry is currently using on a large scale will have to change fundamentally; higher efficiencies, more reuse, alternative raw materials, and alternative sources of energy are all necessary. Electrification All options to achieve these ambitions are currently being considered, but it is clear that the electrification of chemical production processes will be an indispensable component in the future. The field of electrochemistry revolves around the use of chemical compounds for the large-scale storage of energy and, conversely, the large-scale production of organic chemicals using electricity, instead of by burning fossil fuels. For example, with the help of electricity, water and CO2 from the air can be converted into syngas and the raw materials for the production of fuels or plastics. This process is called electrolysis. Scientists are studying and improving such chemical processes, with a major effort being placed on finding catalysts that accelerate electrolysis and make it cost effective. Huge scale This work mainly takes place on a laboratory scale. So, there is still a long way to go. Anyone visiting one of the Dutch chemical clusters, for example in the Eemshaven or the Botlek area, will quickly realize that the enormous scale of production by the chemical industry makes a rapid and painless transition impossible. There are high costs involved. And if that transition is to be completed in 2050, then the chemical plants of the future must be built from 2040 or even 2030 onwards. This leaves little time to develop, test and scale up new chemical processes. If we do not start testing on a relevant, large scale in time, we may develop electrolysis routes that cannot be scaled up at all. If we want to find the desired catalysts on time, we have to think ahead. Dr. Thomas Burdyny Common approach The Delft e-Refinery initiative was created last year to point the way for that approach. Within e-Refinery, around forty scientists from the Faculties of Technology, Policy and Management (TPM), Mechanical Engineering (ME), Applied Sciences (TNW) and Electrical Engineering, Mathematics and Computer Science (EWI) work together to enable multidisciplinary and multi-scale research. In recent weeks, scientists from this e-Refinery have come up with new results. Furthermore the scientists cannot take these steps without governments, business and academic disciplines. Future catalysts For example, in the journal Energy & Environmental Science, mechanical engineer Dr Thomas Burdyny and chemical engineer Dr Wilson Smith provide advice on testing future catalysts. Burdyny: “The development of new catalysts is essential for our search for a form of electrolysis that is efficient on a large scale. Only with the right catalyst can we remove CO2 from the atmosphere and pump it into our economy. Our research now shows that the scale on which the chemical process is implemented (in technical terms: the current density) influences catalytic parameters that determine the efficiency of the process as a whole. In other words, if we do not start testing on a relevant, large scale in time, we may develop electrolysis routes that cannot be scaled up at all. If we want to find the desired catalysts on time, we have to think ahead.” Negative emission Recent results from energy scientist Prof. Andrea Ramirez Ramirez (also published in the journal Energy & Environmental Science) try to steer future developments in the right direction. She reviews the divergent definitions of so-called ‘negative emission technologies’ and proposes a uniform definition. Ramirez Ramirez: “There is a lot of attention for techniques that use more greenhouse gases than they emit, and therefore have a ‘negative emission’. But because of different definitions, we run the risk of wasting time on techniques that actually cause a net increase in greenhouse gases. We propose four criteria for reliably labelling technologies as negative emissions technologies. In short, there must be capture and permanent storage of greenhouse gasses, with the inevitable emissions to achieve this being known in detail and less than the amount of captured greenhouse gas.” There is a lot of attention for techniques that use more greenhouse gases than they emit. But because of large differences in carbon footprint assessments, we run the risk of wasting time on technologies that could actually cause a net increase in greenhouse gases Andrea Ramirez Ramirez e-Refinery The work of Burdyny & Smith and Ramirez Ramirez are excellent examples of the e-Refinery approach. Burdyny: “Changing our energy system is an immense challenge. It requires breakthroughs at the scale level smaller than a human hair up to the scale of entire countries. Collaboration between science and industry and between multiple disciplines is essential. This is the approach of the e-Refinery initiative.” The e-Refinery was established to make the process of electrification of the chemical industry possible on all fronts. In consultation with Dutch industry, it was decided to start with three bulk chemicals: hydrogen, formic acid and ethylene. After that, the electrochemical production of methane and methanol, carbon monoxide and ammonia will also be examined at larger scales. Only through such an electrification will fuels become CO2 neutral in the future. This objective of the e-Refinery is inextricably linked to that of smart electricity storage. By integrating the two sectors, surpluses or shortages can easily be exchanged between electricity-consuming industry and electricity suppliers. To achieve both objectives, the e-Refinery follows an integrated approach; from material design in the laboratory to integration in large-scale systems. Ramirez Ramirez concludes: “Preventing disastrous climate change is a race against time. It requires international cooperation and technological development as we have never seen before.” Paulien Herder Paulien Herder is professor Energy Systems at TU Delft and program leader of e-refinery. “Our goal is to pave the way to the production of fuels and resources from CO2 with the help of sustainable electricity. E-refinery offers a number of promising technologies that will enable us to use CO2 as a raw material for our chemical industry, instead of oil, gas and coal. The products that we are going to create along this electrochemical path can subsequently also be used as a long-term storage medium for sustainable electric energy and as CO2-neutral transport fuels. The e-Refinery technology will thus play a key role in the transition to a climate-neutral society” Paulien Herder +31 15 27 82823 P.M.Herder@tudelft.nl Read more about e-Refinery Strong ambitions The objectives of the international climate agreement in Paris or that of her Dutch sister, the recently presented ‘klimaatakkoord’, are ambitious to say the least. Compared to the 1990 level, greenhouse gas emissions must be reduced by 49% in 2030 and by as much as 95% in 2050. This has significant consequences for our chemical industry. Due to the scale and complexity of the challenge, we have to look far ahead. The chemical processes that this industry is currently using on a large scale will have to change fundamentally; higher efficiencies, more reuse, alternative raw materials, and alternative sources of energy are all necessary. Electrification All options to achieve these ambitions are currently being considered, but it is clear that the electrification of chemical production processes will be an indispensable component in the future. The field of electrochemistry revolves around the use of chemical compounds for the large-scale storage of energy and, conversely, the large-scale production of organic chemicals using electricity, instead of by burning fossil fuels. For example, with the help of electricity, water and CO2 from the air can be converted into syngas and the raw materials for the production of fuels or plastics. This process is called electrolysis. Scientists are studying and improving such chemical processes, with a major effort being placed on finding catalysts that accelerate electrolysis and make it cost effective. Huge scale This work mainly takes place on a laboratory scale. So, there is still a long way to go. Anyone visiting one of the Dutch chemical clusters, for example in the Eemshaven or the Botlek area, will quickly realize that the enormous scale of production by the chemical industry makes a rapid and painless transition impossible. There are high costs involved. And if that transition is to be completed in 2050, then the chemical plants of the future must be built from 2040 or even 2030 onwards. This leaves little time to develop, test and scale up new chemical processes. If we do not start testing on a relevant, large scale in time, we may develop electrolysis routes that cannot be scaled up at all. If we want to find the desired catalysts on time, we have to think ahead. Dr. Thomas Burdyny Common approach The Delft e-Refinery initiative was created last year to point the way for that approach. Within e-Refinery, around forty scientists from the Faculties of Technology, Policy and Management (TPM), Mechanical Engineering (ME), Applied Sciences (TNW) and Electrical Engineering, Mathematics and Computer Science (EWI) work together to enable multidisciplinary and multi-scale research. In recent weeks, scientists from this e-Refinery have come up with new results. Furthermore the scientists cannot take these steps without governments, business and academic disciplines. Future catalysts For example, in the journal Energy & Environmental Science, mechanical engineer Dr Thomas Burdyny and chemical engineer Dr Wilson Smith provide advice on testing future catalysts. Burdyny: “The development of new catalysts is essential for our search for a form of electrolysis that is efficient on a large scale. Only with the right catalyst can we remove CO2 from the atmosphere and pump it into our economy. Our research now shows that the scale on which the chemical process is implemented (in technical terms: the current density) influences catalytic parameters that determine the efficiency of the process as a whole. In other words, if we do not start testing on a relevant, large scale in time, we may develop electrolysis routes that cannot be scaled up at all. If we want to find the desired catalysts on time, we have to think ahead.” Negative emission Recent results from energy scientist Prof. Andrea Ramirez Ramirez (also published in the journal Energy & Environmental Science) try to steer future developments in the right direction. She reviews the divergent definitions of so-called ‘negative emission technologies’ and proposes a uniform definition. Ramirez Ramirez: “There is a lot of attention for techniques that use more greenhouse gases than they emit, and therefore have a ‘negative emission’. But because of different definitions, we run the risk of wasting time on techniques that actually cause a net increase in greenhouse gases. We propose four criteria for reliably labelling technologies as negative emissions technologies. In short, there must be capture and permanent storage of greenhouse gasses, with the inevitable emissions to achieve this being known in detail and less than the amount of captured greenhouse gas.” There is a lot of attention for techniques that use more greenhouse gases than they emit. But because of large differences in carbon footprint assessments, we run the risk of wasting time on technologies that could actually cause a net increase in greenhouse gases Andrea Ramirez Ramirez e-Refinery The work of Burdyny & Smith and Ramirez Ramirez are excellent examples of the e-Refinery approach. Burdyny: “Changing our energy system is an immense challenge. It requires breakthroughs at the scale level smaller than a human hair up to the scale of entire countries. Collaboration between science and industry and between multiple disciplines is essential. This is the approach of the e-Refinery initiative.” The e-Refinery was established to make the process of electrification of the chemical industry possible on all fronts. In consultation with Dutch industry, it was decided to start with three bulk chemicals: hydrogen, formic acid and ethylene. After that, the electrochemical production of methane and methanol, carbon monoxide and ammonia will also be examined at larger scales. Only through such an electrification will fuels become CO2 neutral in the future. This objective of the e-Refinery is inextricably linked to that of smart electricity storage. By integrating the two sectors, surpluses or shortages can easily be exchanged between electricity-consuming industry and electricity suppliers. To achieve both objectives, the e-Refinery follows an integrated approach; from material design in the laboratory to integration in large-scale systems. Ramirez Ramirez concludes: “Preventing disastrous climate change is a race against time. It requires international cooperation and technological development as we have never seen before.” Paulien Herder Paulien Herder is professor Energy Systems at TU Delft and program leader of e-refinery. “Our goal is to pave the way to the production of fuels and resources from CO2 with the help of sustainable electricity. E-refinery offers a number of promising technologies that will enable us to use CO2 as a raw material for our chemical industry, instead of oil, gas and coal. The products that we are going to create along this electrochemical path can subsequently also be used as a long-term storage medium for sustainable electric energy and as CO2-neutral transport fuels. The e-Refinery technology will thus play a key role in the transition to a climate-neutral society” Read more about e-Refinery Related stories In search of better Li-ion batteries and alternatives Developing a digital twin for the electricy grid Intelligent, self-driving wind turbines Related stories

Towards safe surgery worldwide

More people die from treatable surgical conditions than from HIV, malaria and tuberculosis put together. This is what Roos Oosting wants to change with her ground-breaking PhD research into surgical equipment for developing countries. Her goal: to make safe surgery possible anywhere in the world. When Roos Oosting travelled to Kenia four years ago, many people thought she was ‘also a surgeon’, or that she was perhaps selling surgical equipment. That the Delft Global PhD-fellow within the department of Biomechanical Engineering wanted to know how surgical equipment is used in the African hospitals was a new question. As a part of the programme ‘surgery for all’ of TU Delft professor Jenny Dankelman, Oosting investigated the requirements surgical equipment in Africa must meet. Something which received little attention until recently. Surgery in Kenya Oosting contacted a great number of surgeons, biomedical technicians and NGO’s in Kenya, where she lived for several months, and later also in Mozambique and Rwanda. From surveys and interviews it became clear how different the reality is in an African hospital in comparison to one in Europe or North America. Often the electricity supply is unstable, there is a limited access to water -problematic for the cleaning process of equipment- and the maintenance and replacement of parts is much more difficult. Still, it is common practice to donate medical equipment from hospitals in the West, which is not always successful. The equipment is too complicated to repair or is used differently than intended. “We see that things designed for one time use are in fact reused. They are cleaned with a chemical disinfectant, while the materials are not meant for this. Not all pathogens are washed off this way, which creates a risk of infection.” Reality in the operating room If possible Oosting would spend a day with a surgeon. “In the Netherlands we picture an operating room quite differently from what the reality is on the other side of the world. It is incomparable. I would see equipment constantly being dragged from one OR to the next, because there was not enough.” The most surprising for Oosting was the lack of essential surgical equipment, at places where successful surgeries were performed. “Three out of ten hospitals did not have a heart rate monitor. Some did not have a device to deliver oxygen, or to sterilize the instruments. I remember thinking: ‘I hope I never have to lay on this operating table.’ For me that shows the urgency of my research. Everyone deserves a well organised operating room.” Designing for Africa In constant deliberation with local doctors and medical-technical staff, Oosting developed a context-driven design approach for an electrosurgical unit, an important tool used to make incisions and cauterise wounds. “This device needs to be easy to move, thus small and compact, and it has to run on a battery. The accessories have to be reusable and robust. If a bed runs over it, it still has to work,” says Oosting. Other advices are to make surgical equipment meant for Africa suitable for chemical cleaning, and to keep the interface and technical wiring simple. Meaning minimal knowledge is required for its use and it will be easier to repair. “Maintenance is hard to organize, so you can count on it that people will open it up themselves and try to make it work again. So it is better to facilitate that.” Local cooperation and international network Oosting is perhaps most proud of the extensive network she built between TU Delft and the biomedical technology sector in Kenya, Mozambique and Rwanda. In addition to the intensive contact with local surgeons and hospitals also internship projects were set up in three different locations in Kenya. Providing the new generation of biomedical engineers with insights in the local context and facilitating an exchange of knowledge. For example, together with master students Oosting developed software to keep track of the inventory and maintenance of equipment for a hospital in Eldoret, about an eight hour drive from Nairobi. “It is special that there now is a network people can continue working with. There are many students who now want to do their internship in Africa, before there was no possibility for this, I think that is a very valuable result.” Future The ultimate goal is to facilitate the step towards minimal invasive surgery, or keyhole surgery, in Africa. This operation technique which uses very small incisions minimizes the infection risk tremendously, but it also requires more specialized surgical equipment. “People are already trained to do this, now the equipment just needs to be there.” Oosting trusts this can become a reality in the near future. “I have high expectations of the development of Africa.” The brand new doctor is not finished by far. Together with a colleague she started the company CASE (www.case.health), to continue building bridges between the development of surgical equipment and the reality in developing countries. Jenny Dankelman +31 15 27 85565 J.Dankelman@tudelft.nl Roos Oosting R.M.Oosting@tudelft.nl This is a story from TU Delft | Global Initiative When Roos Oosting travelled to Kenia four years ago, many people thought she was ‘also a surgeon’, or that she was perhaps selling surgical equipment. That the Delft Global PhD-fellow within the department of Biomechanical Engineering wanted to know how surgical equipment is used in the African hospitals was a new question. As a part of the programme ‘surgery for all’ of TU Delft professor Jenny Dankelman, Oosting investigated the requirements surgical equipment in Africa must meet. Something which received little attention until recently. Surgery in Kenya Oosting contacted a great number of surgeons, biomedical technicians and NGO’s in Kenya, where she lived for several months, and later also in Mozambique and Rwanda. From surveys and interviews it became clear how different the reality is in an African hospital in comparison to one in Europe or North America. Often the electricity supply is unstable, there is a limited access to water -problematic for the cleaning process of equipment- and the maintenance and replacement of parts is much more difficult. Still, it is common practice to donate medical equipment from hospitals in the West, which is not always successful. The equipment is too complicated to repair or is used differently than intended. “We see that things designed for one time use are in fact reused. They are cleaned with a chemical disinfectant, while the materials are not meant for this. Not all pathogens are washed off this way, which creates a risk of infection.” Reality in the operating room If possible Oosting would spend a day with a surgeon. “In the Netherlands we picture an operating room quite differently from what the reality is on the other side of the world. It is incomparable. I would see equipment constantly being dragged from one OR to the next, because there was not enough.” The most surprising for Oosting was the lack of essential surgical equipment, at places where successful surgeries were performed. “Three out of ten hospitals did not have a heart rate monitor. Some did not have a device to deliver oxygen, or to sterilize the instruments. I remember thinking: ‘I hope I never have to lay on this operating table.’ For me that shows the urgency of my research. Everyone deserves a well organised operating room.” Designing for Africa In constant deliberation with local doctors and medical-technical staff, Oosting developed a context-driven design approach for an electrosurgical unit, an important tool used to make incisions and cauterise wounds. “This device needs to be easy to move, thus small and compact, and it has to run on a battery. The accessories have to be reusable and robust. If a bed runs over it, it still has to work,” says Oosting. Other advices are to make surgical equipment meant for Africa suitable for chemical cleaning, and to keep the interface and technical wiring simple. Meaning minimal knowledge is required for its use and it will be easier to repair. “Maintenance is hard to organize, so you can count on it that people will open it up themselves and try to make it work again. So it is better to facilitate that.” Local cooperation and international network Oosting is perhaps most proud of the extensive network she built between TU Delft and the biomedical technology sector in Kenya, Mozambique and Rwanda. In addition to the intensive contact with local surgeons and hospitals also internship projects were set up in three different locations in Kenya. Providing the new generation of biomedical engineers with insights in the local context and facilitating an exchange of knowledge. For example, together with master students Oosting developed software to keep track of the inventory and maintenance of equipment for a hospital in Eldoret, about an eight hour drive from Nairobi. “It is special that there now is a network people can continue working with. There are many students who now want to do their internship in Africa, before there was no possibility for this, I think that is a very valuable result.” Future The ultimate goal is to facilitate the step towards minimal invasive surgery, or keyhole surgery, in Africa. This operation technique which uses very small incisions minimizes the infection risk tremendously, but it also requires more specialized surgical equipment. “People are already trained to do this, now the equipment just needs to be there.” Oosting trusts this can become a reality in the near future. “I have high expectations of the development of Africa.” The brand new doctor is not finished by far. Together with a colleague she started the company CASE (www.case.health), to continue building bridges between the development of surgical equipment and the reality in developing countries. This is a story from TU Delft | Global Initiative Related stories Surgery for all Saving lives with mathematics Affordable MRI

The unexpected science of steel and chocolate

Chocolate letters, Christmas tree ornaments and the very familiar ice-cream cake with crunch layers: for many people chocolate is inextricably linked to the holiday season. Hardly anyone realises that making creamy, soft chocolate has much in common with making super-strong steel. Humanity has been using steel for thousands of years, but until recently its production was a question of trial and error. ‘A swordsmith in the Middle Ages didn’t know what we know today. If a sword came out right, then it was viewed as a “magical” sword; the rest could be thrown back into the melting pot,’ says Jilt Sietsma, professor of microstructure control in metals. ‘A good smith was therefore a key player in a city’s safety,’ adds Marcel Sluiter, associate professor of computational materials science. ‘Two discoveries in the late nineteenth century gave our understanding of steel a huge impetus: the electron and X-radiation. Today, X-radiation techniques and electron microscopes enable us to examine the structure of materials in minute detail; the electron is crucial to this structure,’ says Sietsma. A key observation that could be made as a result is that steel undergoes phase transitions within a solid state. We understand phases in daily life as the transition of a liquid to a solid or a gas, or vice versa, but when a solid undergoes a phase transition the atoms arrange themselves in a different crystal structure. ‘Steel contains 96% iron by weight and half a per cent carbon by weight. The crystal structure is stable at room temperature, but if you heat it up, the way the carbon atoms are arranged in the iron changes, and at a slightly larger scale, the microstructure, an enormous collection of crystals start to form,’ says Sietsma. It’s these microstructures that are responsible for the properties of steel. To influence these microstructures, steel is heated to 900 degrees, or what’s referred to as the gamma phase, but we use steel at room temperature, so it’s cooled down again. ‘Atoms are always moving towards a steady state. In decreasing temperatures they can move increasingly slowly; so it’s all about how much time we give the atoms,’ he explains. ‘The trick is to not allow them to reach a steady state but something in between, so you can achieve a microstructure that’s between the one condition and the other. You interrupt that transitional process by cooling down quickly to room temperature.’ Persen en walsen The different microstructures don’t only emerge as a result of temperature changes but also mechanical treatments such as pressing or rolling. ‘By alternating these treatments during production you can create many different properties and thus increase the strength, for example, by a factor of ten. That happens at an extremely large scale, in which sheet metal undergoes a specifically selected temperature-time profile,’ Sluiter explains. Strength vs. ductility Two important properties of steel are its strength and the degree to which it can be deformed, the ductility. ‘Depending on the application, you strike a balance between strength and ductility. For example, you want the crumple zone of a car to absorb the force of a collision, so that material has to be as deformable as possible.’ The microstructure plays a role here too, because large crystals are more deformable but less strong, while small crystals are strong but less deformable. One of the challenges of the research is to increase both the strength and the elongation of steel, for example to produce lighter cars. Materials science That the microstructure leads to certain properties is not only true of steel: it’s the central theme in materials science. ‘Steel is really special, because of the phase transition in the solid state, which creates so many possibilities for variation in the properties. But in glass, plastic and concrete the microstructures also has an impact on the properties. It’s the same for all materials,’ says Sluiter. ‘Those properties are the result of the chosen composition, the subsequent treatment and the resulting microstructure,’ Sietsma explains. ‘For the development of materials, you usually reason the other way around. Depending on the desired properties, you examine which microstructure you need and how to achieve it.’ Chocolate Just like in materials science, microstructures play a major role in nutritional research, where they influence properties such as taste and shelf life. There are striking similarities between steel and chocolate: ‘Temperature change, phase transition, deformation: chocolate is comparable in all these areas,’ says Sluiter. ‘The atoms in chocolate seek equilibrium. That, in turn, depends on the composition, the temperature and the way that you deform. It’s also true for chocolate that the equilibrium structure is not the structure that you’re looking for. If that was the case, then it would be a lot easier to produce.’ Phase five Deforming chocolate is called conching, or rolling, just like with steel. It takes place during the mixing of cocoa, cocoa butter, sugar, milk powder and other ingredients. Then comes the tempering. ‘Treating the chocolate with temperature is extremely important, just like with steel, because that’s when the microstructure is formed,’ Sluiter explains. Chocolate is a complex product that can have six different crystal forms. ‘Crystal form five is the one that the chocolatier aims for. It has a melting point of 32 to 34 degrees. The temperature variations between the different forms are very close to each other, however. If the setting, the cooling off, does not occur properly, then you’ll end up in the wrong chocolate phase. Then it will melt too quickly or not at all. That won’t do the eating experience any good.’ Chocolate is unstable. That’s evident if you keep chocolate for too long or in warm conditions. The chocolate will lose it sheen and get a white film of sugar or fat – a sign that the chocolate is moving towards crystal form six. Science of steel and chocolate Making chocolate is therefore purely a matter of materials science. That also makes it an excellent subject for talking about science, especially in the month of December. In December 2018, Marcel Sluiter gave a lecture at the University of Twente in Enschede. He did that together with local chocolatier Jan Meen. ‘The participants were all given a bag of chocolate that they were allowed to taste during the lecture to discover the different phase types,’ Sluiter says. In March 2017, there was even an entire symposium in Delft where chocolate and steel experts from the four technology universities spoke about the underlying processes and structures of chocolate and steel. ‘We already have a solid understanding of the principles of thermodynamics and the kinetic processes that steel and chocolate share. But that probably wasn’t the case 100 years ago, when the basic principles weren’t as well known yet. The current research focuses on the details of the processes, and in that sense there are differences between steel and chocolate,’ Sietsma says. Future-proof That certainly doesn’t mean that there’s nothing left to discover in steel research. One line of research is improving the blast furnace process. ‘A great deal of CO2 is released during the production of steel, especially during the extraction of iron from iron ore. This step is thus extremely important towards making the steel industry more sustainable,’ Sietsma explains. On the other hand, steel is the most reused material in the world: in 2014, 86% of steel waste was recycled. ‘Steel can be endlessly reused, much more so than plastic, for example,’ Sluiter says. Still, every year about 1,800 million tons of steel is still being produced. That’s because we continue to build new cities, bridges and railway lines. ‘But the raw materials for that steel, iron and carbon, are cheap and plentiful. Moreover, it contains few special elements. So steel is a highly future-proof material.’ Marcel Sluiter +31 15 27 84922 M.H.F.Sluiter@tudelft.nl Jilt Sietsma +31 15 27 82284 J.Sietsma@tudelft.nl This is a story from ME Humanity has been using steel for thousands of years, but until recently its production was a question of trial and error. ‘A swordsmith in the Middle Ages didn’t know what we know today. If a sword came out right, then it was viewed as a “magical” sword; the rest could be thrown back into the melting pot,’ says Jilt Sietsma, professor of microstructure control in metals. ‘A good smith was therefore a key player in a city’s safety,’ adds Marcel Sluiter, associate professor of computational materials science. ‘Two discoveries in the late nineteenth century gave our understanding of steel a huge impetus: the electron and X-radiation. Today, X-radiation techniques and electron microscopes enable us to examine the structure of materials in minute detail; the electron is crucial to this structure,’ says Sietsma. A key observation that could be made as a result is that steel undergoes phase transitions within a solid state. We understand phases in daily life as the transition of a liquid to a solid or a gas, or vice versa, but when a solid undergoes a phase transition the atoms arrange themselves in a different crystal structure. ‘Steel contains 96% iron by weight and half a per cent carbon by weight. The crystal structure is stable at room temperature, but if you heat it up, the way the carbon atoms are arranged in the iron changes, and at a slightly larger scale, the microstructure, an enormous collection of crystals start to form,’ says Sietsma. It’s these microstructures that are responsible for the properties of steel. To influence these microstructures, steel is heated to 900 degrees, or what’s referred to as the gamma phase, but we use steel at room temperature, so it’s cooled down again. ‘Atoms are always moving towards a steady state. In decreasing temperatures they can move increasingly slowly; so it’s all about how much time we give the atoms,’ he explains. ‘The trick is to not allow them to reach a steady state but something in between, so you can achieve a microstructure that’s between the one condition and the other. You interrupt that transitional process by cooling down quickly to room temperature.’ Persen en walsen The different microstructures don’t only emerge as a result of temperature changes but also mechanical treatments such as pressing or rolling. ‘By alternating these treatments during production you can create many different properties and thus increase the strength, for example, by a factor of ten. That happens at an extremely large scale, in which sheet metal undergoes a specifically selected temperature-time profile,’ Sluiter explains. Strength vs. ductility Two important properties of steel are its strength and the degree to which it can be deformed, the ductility. ‘Depending on the application, you strike a balance between strength and ductility. For example, you want the crumple zone of a car to absorb the force of a collision, so that material has to be as deformable as possible.’ The microstructure plays a role here too, because large crystals are more deformable but less strong, while small crystals are strong but less deformable. One of the challenges of the research is to increase both the strength and the elongation of steel, for example to produce lighter cars. Materials science That the microstructure leads to certain properties is not only true of steel: it’s the central theme in materials science. ‘Steel is really special, because of the phase transition in the solid state, which creates so many possibilities for variation in the properties. But in glass, plastic and concrete the microstructures also has an impact on the properties. It’s the same for all materials,’ says Sluiter. ‘Those properties are the result of the chosen composition, the subsequent treatment and the resulting microstructure,’ Sietsma explains. ‘For the development of materials, you usually reason the other way around. Depending on the desired properties, you examine which microstructure you need and how to achieve it.’ Chocolate Just like in materials science, microstructures play a major role in nutritional research, where they influence properties such as taste and shelf life. There are striking similarities between steel and chocolate: ‘Temperature change, phase transition, deformation: chocolate is comparable in all these areas,’ says Sluiter. ‘The atoms in chocolate seek equilibrium. That, in turn, depends on the composition, the temperature and the way that you deform. It’s also true for chocolate that the equilibrium structure is not the structure that you’re looking for. If that was the case, then it would be a lot easier to produce.’ Phase five Deforming chocolate is called conching, or rolling, just like with steel. It takes place during the mixing of cocoa, cocoa butter, sugar, milk powder and other ingredients. Then comes the tempering. ‘Treating the chocolate with temperature is extremely important, just like with steel, because that’s when the microstructure is formed,’ Sluiter explains. Chocolate is a complex product that can have six different crystal forms. ‘Crystal form five is the one that the chocolatier aims for. It has a melting point of 32 to 34 degrees. The temperature variations between the different forms are very close to each other, however. If the setting, the cooling off, does not occur properly, then you’ll end up in the wrong chocolate phase. Then it will melt too quickly or not at all. That won’t do the eating experience any good.’ Chocolate is unstable. That’s evident if you keep chocolate for too long or in warm conditions. The chocolate will lose it sheen and get a white film of sugar or fat – a sign that the chocolate is moving towards crystal form six. Science of steel and chocolate Making chocolate is therefore purely a matter of materials science. That also makes it an excellent subject for talking about science, especially in the month of December. In December 2018, Marcel Sluiter gave a lecture at the University of Twente in Enschede. He did that together with local chocolatier Jan Meen. ‘The participants were all given a bag of chocolate that they were allowed to taste during the lecture to discover the different phase types,’ Sluiter says. In March 2017, there was even an entire symposium in Delft where chocolate and steel experts from the four technology universities spoke about the underlying processes and structures of chocolate and steel. ‘We already have a solid understanding of the principles of thermodynamics and the kinetic processes that steel and chocolate share. But that probably wasn’t the case 100 years ago, when the basic principles weren’t as well known yet. The current research focuses on the details of the processes, and in that sense there are differences between steel and chocolate,’ Sietsma says. Future-proof That certainly doesn’t mean that there’s nothing left to discover in steel research. One line of research is improving the blast furnace process. ‘A great deal of CO2 is released during the production of steel, especially during the extraction of iron from iron ore. This step is thus extremely important towards making the steel industry more sustainable,’ Sietsma explains. On the other hand, steel is the most reused material in the world: in 2014, 86% of steel waste was recycled. ‘Steel can be endlessly reused, much more so than plastic, for example,’ Sluiter says. Still, every year about 1,800 million tons of steel is still being produced. That’s because we continue to build new cities, bridges and railway lines. ‘But the raw materials for that steel, iron and carbon, are cheap and plentiful. Moreover, it contains few special elements. So steel is a highly future-proof material.’ Marcel Sluiter +31 15 27 84922 M.H.F.Sluiter@tudelft.nl Jilt Sietsma +31 15 27 82284 J.Sietsma@tudelft.nl This is a story from ME

Playing scientifically sound baseball and tennis

If you watch a baseball player pitching a ball or a tennis player serving, then you’re immediately struck by the fact that their arms can rotate further back. This enables them to throw a ball or serve much harder. On the other hand, they get injured more quickly. Bart van Trigt is developing a measurement system to prevent overhead injuries. Baseball is one of the most played sports in the world. It’s less popular in the Netherlands than in some other countries, yet we have the most successful baseball team in Europe. We were even world champions once, in 2011. Who knows, we may even be the talk of the town during the 2020 Olympic Games, when baseball will be reintroduced to the summer games. ‘But then we have to do everything in our power to keep our athletes free from injury,’ says Bart van Trigt, PhD candidate in the field of BioMechanical Engineering at TU Delft.He is developing a measurement system to prevent overhead injuries in both baseball and tennis together with PhD candidate Ton Leenen, who is conducting doctoral research at VU Amsterdam in the field of Human Movement Sciences. The perfect pitch The most common injury that pitchers suffer from is a torn ligament on the inside of the elbow. ‘We want to find out what the perfect pitching motion or serve is for an athlete. In other words, what’s the maximum speed you can pitch or serve a ball without totally wrecking your arms?’ Leenen says. The researchers’ initial aim is to keep the small number of good baseball and tennis players in the Netherlands free from injuries. In the long term, they hope to use this knowledge with amateur athletes who are prone to injury in our country as well. In the United States, where far more people practice these sports, there’s much less focus on this issue. ‘When someone gets injured in the States, the immediate verdict is that they’re not good enough,’ Van Trigt says. The PhD candidate conjures up four graphs on his laptop, in which each line shows the result of a sensor that was placed on part of the body. ‘A good pitcher starts his throw by putting his foot down, then he transmits the energy of this movement to his knee. Our research measures how that energy is then transmitted to the pelvis, the torso and subsequently the lower arm and upper arm. When there’s a perfect motion, then the graphs show consecutive peaks in all four sensors,’ the researcher says. ‘People are at risk of receiving injuries,’ Leenen adds, ‘when they don’t transmit the energy from the torso effectively to the upper arm, for example. Then the peaks don’t occur in a neat sequence. In order to make up for the lost energy, an athlete may compensate by applying more force with his upper or lower arm, which increases the chances of injury in that region. We want to test whether a person’s performance decreases if he does not optimally use the series of motions while pitching, which we also refer to as the kinetic chain. We also want to know if the stress on the shoulder or elbow is higher and whether that leads to injury. We’re assuming it does.’ The project that Van Trigt and Leenen are working on is one of nine projects belonging to a NWO programme launched in April 2018 which aims to prevent sports injuries. The rationale is that half of these injuries are preventable, which would generate savings of 460 million euros a year in terms of direct medical costs. Professor Frans van der Helm, director of the TU Delft Sports Engineering Institute, is managing the entire research programme on behalf of TU Delft, which also includes the international tennis federation, the KNLTB, the KNBSB and NOC*NSF. Moreover, the PhD candidates are receiving daily guidance from professor DirkJan Veeger from TU Delft and Marco Hoozemans from VU Amsterdam. Research is also being conducted in the NWO programme on how to extract information from a variety of data that is useful for athletes, discovering what is actually the best way to measure movements, and which sensors you need to achieve that. Research challenges ‘The sensors available on the market today are unable to handle the speeds achieved by tennis and baseball players, Van Trigt says. ‘The movement of a pitch takes 145 milliseconds to complete. Pitchers rotate their arm 9000 degrees per second and then release the ball extremely quickly. In terms of speed it looks like they’re rotating their arm 25 times a second. However, we still aren’t able to determine that well enough yet.’ Indeed, this is also his project’s greatest challenge: the ability to measure good data in the field the researchers first must have high-tech sensors at their disposal. They want to fasten them to shirts, so that professional athletes can wear them without their performance being affected. Van Trigt and Leenen hope to develop a measurement system in five years’ time that is able to monitor the stress on baseball and tennis players. It will track how many balls athletes throw or hit, for example, the timing of the body parts in relation to one another and the speed of the ball. Each player’s data will be linked to an app. ‘Ideally, an athlete’s coach would be able to immediately see how someone is performing and what the odds are that he or she will suffer an injury. Based on that he can then make a decision to coach someone so they don’t become injured or replace a player,’ Van Trigt says. ‘But this kind of a measurement system won’t get you there on its own,’ Leenen warns. He explains that sports science has been around for a long time. Yet people have not been using it in the practice of sports for that long yet. Many coaches ignore what it has to say. That’s because researchers aren’t always to be found on sports fields, but analyse figures in their offices. ‘As researchers in the field of human movement science we monitor movements with the aid of sensors, while coaches have the experience to see the same movements with their naked eye,’ the gentlemen explain. They’re optimistic about the future. ‘In ten years’ time, science will be supporting practice much more than now. Then baseball and tennis players will be performing at an even higher level, and what’s more they’ll have far fewer injuries.’ Bart van Trigt Ton Leenen +316 50 56 20 29 a.j.r.leenen@vu.nl This is a story from ME Baseball is one of the most played sports in the world. It’s less popular in the Netherlands than in some other countries, yet we have the most successful baseball team in Europe. We were even world champions once, in 2011. Who knows, we may even be the talk of the town during the 2020 Olympic Games, when baseball will be reintroduced to the summer games. ‘But then we have to do everything in our power to keep our athletes free from injury,’ says Bart van Trigt, PhD candidate in the field of BioMechanical Engineering at TU Delft.He is developing a measurement system to prevent overhead injuries in both baseball and tennis together with PhD candidate Ton Leenen, who is conducting doctoral research at VU Amsterdam in the field of Human Movement Sciences. The perfect pitch The most common injury that pitchers suffer from is a torn ligament on the inside of the elbow. ‘We want to find out what the perfect pitching motion or serve is for an athlete. In other words, what’s the maximum speed you can pitch or serve a ball without totally wrecking your arms?’ Leenen says. The researchers’ initial aim is to keep the small number of good baseball and tennis players in the Netherlands free from injuries. In the long term, they hope to use this knowledge with amateur athletes who are prone to injury in our country as well. In the United States, where far more people practice these sports, there’s much less focus on this issue. ‘When someone gets injured in the States, the immediate verdict is that they’re not good enough,’ Van Trigt says. The PhD candidate conjures up four graphs on his laptop, in which each line shows the result of a sensor that was placed on part of the body. ‘A good pitcher starts his throw by putting his foot down, then he transmits the energy of this movement to his knee. Our research measures how that energy is then transmitted to the pelvis, the torso and subsequently the lower arm and upper arm. When there’s a perfect motion, then the graphs show consecutive peaks in all four sensors,’ the researcher says. ‘People are at risk of receiving injuries,’ Leenen adds, ‘when they don’t transmit the energy from the torso effectively to the upper arm, for example. Then the peaks don’t occur in a neat sequence. In order to make up for the lost energy, an athlete may compensate by applying more force with his upper or lower arm, which increases the chances of injury in that region. We want to test whether a person’s performance decreases if he does not optimally use the series of motions while pitching, which we also refer to as the kinetic chain. We also want to know if the stress on the shoulder or elbow is higher and whether that leads to injury. We’re assuming it does.’ The project that Van Trigt and Leenen are working on is one of nine projects belonging to a NWO programme launched in April 2018 which aims to prevent sports injuries. The rationale is that half of these injuries are preventable, which would generate savings of 460 million euros a year in terms of direct medical costs. Professor Frans van der Helm, director of the TU Delft Sports Engineering Institute, is managing the entire research programme on behalf of TU Delft, which also includes the international tennis federation, the KNLTB, the KNBSB and NOC*NSF. Moreover, the PhD candidates are receiving daily guidance from professor DirkJan Veeger from TU Delft and Marco Hoozemans from VU Amsterdam. Research is also being conducted in the NWO programme on how to extract information from a variety of data that is useful for athletes, discovering what is actually the best way to measure movements, and which sensors you need to achieve that. Research challenges ‘The sensors available on the market today are unable to handle the speeds achieved by tennis and baseball players, Van Trigt says. ‘The movement of a pitch takes 145 milliseconds to complete. Pitchers rotate their arm 9000 degrees per second and then release the ball extremely quickly. In terms of speed it looks like they’re rotating their arm 25 times a second. However, we still aren’t able to determine that well enough yet.’ Indeed, this is also his project’s greatest challenge: the ability to measure good data in the field the researchers first must have high-tech sensors at their disposal. They want to fasten them to shirts, so that professional athletes can wear them without their performance being affected. Van Trigt and Leenen hope to develop a measurement system in five years’ time that is able to monitor the stress on baseball and tennis players. It will track how many balls athletes throw or hit, for example, the timing of the body parts in relation to one another and the speed of the ball. Each player’s data will be linked to an app. ‘Ideally, an athlete’s coach would be able to immediately see how someone is performing and what the odds are that he or she will suffer an injury. Based on that he can then make a decision to coach someone so they don’t become injured or replace a player,’ Van Trigt says. ‘But this kind of a measurement system won’t get you there on its own,’ Leenen warns. He explains that sports science has been around for a long time. Yet people have not been using it in the practice of sports for that long yet. Many coaches ignore what it has to say. That’s because researchers aren’t always to be found on sports fields, but analyse figures in their offices. ‘As researchers in the field of human movement science we monitor movements with the aid of sensors, while coaches have the experience to see the same movements with their naked eye,’ the gentlemen explain. They’re optimistic about the future. ‘In ten years’ time, science will be supporting practice much more than now. Then baseball and tennis players will be performing at an even higher level, and what’s more they’ll have far fewer injuries.’ Bart van Trigt This is a story from ME Related stories Surgery for all Tinkering under the bonnet of life CloudCuddle

Control theory in a selfish world

From self-driving cars, smart traffic lights to energy systems balancing supply and demand: the future is filled with autonomous systems. But what happens if autonomous systems are put together and need to work together? Sergio Grammatico aims to deal with non-cooperative agents such as human-driven cars among autonomous vehicles. The next frontier in autonomous systems Sergio Grammatico, assistant professor at the Delft Center for Systems and Control, is already thinking about the next step: bringing multiple autonomous systems together in a ‘system of systems’ - for example, a highway full of self-coordinating, self-driving cars. Based on the mathematical principles of control theory, robots and vehicles have been taught to function autonomously for decades. Grammatico: “Thanks to today’s computational capabilities, we now have local intelligent systems that can fully operate by themselves.” This coordination among autonomous ‘agents’ is what Grammatico calls the next frontier. Multi-agent control “Think of modern traffic control. Individual traffic lights are programmed such that they can do a great job within the local surrounding of an intersection. But if you think in the context of a larger area such as an entire city, then it would be much more helpful if there is coordination among traffic lights.” This is where multi-agent control theory comes into the picture. Another example: modern power grids. “There used to be a single control system managing the power flow from generators to consumers. Nowadays, energy production, storage and consumption take place everywhere, for example in the photovoltaic panels on our roofs. Multi-agent control is essential to make all these individual systems work together in a smart power grid.” Selfish agents Why is the coordination among multiple intelligent systems so difficult? One of the reasons is that not all participating systems have the same interest in contributing to the collective benefit. Some may prefer individual benefits. “We do this every day without noticing it. While driving our car, we just want to arrive at our destination, and care little about the other cars sharing the highway with us. Every energy company making use of the power grid just wants to maximize its own revenues. In mathematical terms, these selfish participants are called non-cooperative. How can we get drivers who are willing to hand over control of their vehicle to the control system, and drivers who do not want to, to work together? What incentives or control signals would make them coordinate their behaviour? Studying populations of cooperative and non-cooperative agents is very important if we want to develop applications in realistic situations. That’s what my ERC project is about.” Game theory While the dynamics are very complex for just one autonomous vehicle, they become even more complex when multiple vehicles interact. Grammatico is adamant that dynamic game theory will provide the keys to solving these coordination problems. “Game theory helps us mathematically model the interests and behaviour of non-cooperative agents. I will use another branch of mathematics – operator theory – combined with distributed control to exploit game models and develop mechanisms to control non-cooperative agents. These tools are already being used in other branches of mathematics, but the approach itself is completely new within the systems and control community.” The most challenging part, Grammatico explains, will be to combine continuous variables and logic/discrete variables. “In autonomous driving, we are not just dealing with continuous variables, such as velocity and acceleration. Important parameters, such as the car’s direction indicators which can be on or off, or the lane the car is driving in, are discrete variables. It will be a huge achievement if we will be able to control such multi-agent hybrid (namely, continuous/discrete) systems. It will open up a completely new research area!” I have always been fascinated by the interplay of engineering and mathematical theories. Engineering and Mathematics come together in multi-agent control theory, indeed. Sergio Grammatico Experimental tests Grammatico will use the ERC funds to set up a framework, a theoretical background, for other researchers to build upon and to generate software that can be immediately be embedded in practical platforms such a robots and autonomous cars. “I have a number of applications in mind for which I want to use the new theory to derive control algorithms, implement them and validate them in practice.” After full-scale numerical simulations, the first experimental tests will be done using eight miniature robotic cars. “If this is successful, we can take the next step and test our algorithms in real-life scenarios on the TU Delft campus, as part of the Green Village living lab programme.” Technology and mathematics Grammatico studied both Engineering Science and Automatic Control Engineering at the University of Pisa. “I have always been fascinated by the interplay of engineering applications and mathematical theories. Engineering and the power of mathematics come together in multi-agent control theory.” In 2017, he moved to Delft University of Technology where he set up his own group funded by Netherlands Organization for Scientific Research (NWO) and now also by the European Research Council (ERC). “Delft is a great place to carry out this kind of research because it has very strong tradition in the field of systems and control. The university has smart people in related disciplines, such as applied mathematics and electrical engineering, and also in different application domains.” Mobility and energy What developments does Grammatico see at the horizon? “I think the full electrification of our cars will take place sooner or later. When all cars are electric, the fields of mobility and energy will come together. We will no longer be able to differentiate between power systems and mobility systems – they will simply merge. I see this as the next engineering challenge for our society. My ERC project will provide the tools to start studying those integrated energy/mobility challenges.” Sergio Grammatico +31 15 27 83593 S.Grammatico@tudelft.nl Academic website This is a story from ME The next frontier in autonomous systems Sergio Grammatico, assistant professor at the Delft Center for Systems and Control, is already thinking about the next step: bringing multiple autonomous systems together in a ‘system of systems’ - for example, a highway full of self-coordinating, self-driving cars. Based on the mathematical principles of control theory, robots and vehicles have been taught to function autonomously for decades. Grammatico: “Thanks to today’s computational capabilities, we now have local intelligent systems that can fully operate by themselves.” This coordination among autonomous ‘agents’ is what Grammatico calls the next frontier. Multi-agent control “Think of modern traffic control. Individual traffic lights are programmed such that they can do a great job within the local surrounding of an intersection. But if you think in the context of a larger area such as an entire city, then it would be much more helpful if there is coordination among traffic lights.” This is where multi-agent control theory comes into the picture. Another example: modern power grids. “There used to be a single control system managing the power flow from generators to consumers. Nowadays, energy production, storage and consumption take place everywhere, for example in the photovoltaic panels on our roofs. Multi-agent control is essential to make all these individual systems work together in a smart power grid.” Selfish agents Why is the coordination among multiple intelligent systems so difficult? One of the reasons is that not all participating systems have the same interest in contributing to the collective benefit. Some may prefer individual benefits. “We do this every day without noticing it. While driving our car, we just want to arrive at our destination, and care little about the other cars sharing the highway with us. Every energy company making use of the power grid just wants to maximize its own revenues. In mathematical terms, these selfish participants are called non-cooperative. How can we get drivers who are willing to hand over control of their vehicle to the control system, and drivers who do not want to, to work together? What incentives or control signals would make them coordinate their behaviour? Studying populations of cooperative and non-cooperative agents is very important if we want to develop applications in realistic situations. That’s what my ERC project is about.” Game theory While the dynamics are very complex for just one autonomous vehicle, they become even more complex when multiple vehicles interact. Grammatico is adamant that dynamic game theory will provide the keys to solving these coordination problems. “Game theory helps us mathematically model the interests and behaviour of non-cooperative agents. I will use another branch of mathematics – operator theory – combined with distributed control to exploit game models and develop mechanisms to control non-cooperative agents. These tools are already being used in other branches of mathematics, but the approach itself is completely new within the systems and control community.” The most challenging part, Grammatico explains, will be to combine continuous variables and logic/discrete variables. “In autonomous driving, we are not just dealing with continuous variables, such as velocity and acceleration. Important parameters, such as the car’s direction indicators which can be on or off, or the lane the car is driving in, are discrete variables. It will be a huge achievement if we will be able to control such multi-agent hybrid (namely, continuous/discrete) systems. It will open up a completely new research area!” I have always been fascinated by the interplay of engineering and mathematical theories. Engineering and Mathematics come together in multi-agent control theory, indeed. Sergio Grammatico Experimental tests Grammatico will use the ERC funds to set up a framework, a theoretical background, for other researchers to build upon and to generate software that can be immediately be embedded in practical platforms such a robots and autonomous cars. “I have a number of applications in mind for which I want to use the new theory to derive control algorithms, implement them and validate them in practice.” After full-scale numerical simulations, the first experimental tests will be done using eight miniature robotic cars. “If this is successful, we can take the next step and test our algorithms in real-life scenarios on the TU Delft campus, as part of the Green Village living lab programme.” Technology and mathematics Grammatico studied both Engineering Science and Automatic Control Engineering at the University of Pisa. “I have always been fascinated by the interplay of engineering applications and mathematical theories. Engineering and the power of mathematics come together in multi-agent control theory.” In 2017, he moved to Delft University of Technology where he set up his own group funded by Netherlands Organization for Scientific Research (NWO) and now also by the European Research Council (ERC). “Delft is a great place to carry out this kind of research because it has very strong tradition in the field of systems and control. The university has smart people in related disciplines, such as applied mathematics and electrical engineering, and also in different application domains.” Mobility and energy What developments does Grammatico see at the horizon? “I think the full electrification of our cars will take place sooner or later. When all cars are electric, the fields of mobility and energy will come together. We will no longer be able to differentiate between power systems and mobility systems – they will simply merge. I see this as the next engineering challenge for our society. My ERC project will provide the tools to start studying those integrated energy/mobility challenges.” Sergio Grammatico +31 15 27 83593 S.Grammatico@tudelft.nl Academic website This is a story from ME Related stories The responsibility gap with self driving cars The impact of algorithms Roboats in Amsterdam