Filter results

9833 resultaten

Understanding the learning process: machine learning and computational chemistry for hydrogenation

Machine learning is being mentioned all around, but can it be applied to modelling homogeneous catalysis? Researchers from TU Delft together with Janssen Pharmaceuticals published an extensive study accompanied by one of the biggest datasets on rhodium-catalyzed hydrogenation in Chemical Science trying to answer this question. Adarsh Kalikadien Evgeny Pidko For more than half a century, Rhodium-based catalysts have been used to produce chiral molecules via the asymmetric hydrogenation of prochiral olefins. The importance of this transformation was acknowledged by a Nobel prize given to Noyori and Knowles for their contributions in this field. Nowadays, asymmetric hydrogenation catalysts are widely used in the pharmaceutical industry, numerous chiral ligands are available to tackle a wide range of prochiral substrates and the reaction mechanism has been extensively studied. Consequently, one would expect that finding the best catalyst for the asymmetric hydrogenation of a new substrate is a trivial task. Unfortunately, this is not the case and a tedious and costly experimental screening is still needed. Adarsh Kalikadien and Evgeny Pidko from TU Delft together with experts in high-throughput-experimentation, data science and computational chemistry from Janssen Pharmaceutica in Belgium decided to investigate whether a well-trained machine could do the job. To their surprise, the machine was actually not able to learn as much as they expected. The idea was to set up a simple model reaction with a well-known rhodium catalyst. Based on the experimental data generated by the high-throughput experimentation team of Janssen, a computational dataset was built to which multiple machine learning models were applied. “We digitalized the 192 catalyst structures and represented them with features of various levels of complexity for the machine learning models,” says Kalikadien, a PhD student in Pidko’s group. "The interesting thing was that all the simpler models, including the random model, showed similar performances as the expensive variant, which intrigued us. It turned out to be an early indication that the machine was not really learning anything useful.” "One of our conclusions was, when tested more extensively, that for an out-of-domain modeling approach, it doesn't matter what representation you put in”. Nevertheless, although the team was not able to build an accurate model, their study was worth publishing. The publication process went relatively smoothly. “Although the first journal we contacted rejected our submission as too specialized, the high-impact journal Chemical Science saw the value of this work. Not many researchers are interested in just seeing the R2 value of a model and then having no possibility to use it, they are probably interested in an in-depth analysis like ours. So we were able to submit our data, code and even interactive figures there for everyone to use.” At the moment there is a big incentive for publishing negative data in order to help the community to assess the true added value of machine learning, since models trained on mainly positive results tend to become very biased. "We made everything open source," says Kalikadien. "Not only is all the data accessible, but we also offer the code including packages and instructions, so that anyone who is interested can do the same type of research." In this way, they have published one of the largest datasets of a certain type of hydrogenation reaction. What's next? "Our representation of the catalyst wasn't as meaningful for the machine learning models as we had hoped, so we are now looking for a representation that may be less simplified but still as simple as possible," says Kalikadien. "Creating a digital representation of your catalyst should not cost way more money than running the actual experiment, so we are trying to incorporate more information from the reaction mechanism into the model without making it too extensive. A more dynamic and hopefully more informative version of the representation." Read the publication Adarsh Kalikadien, Cecile Valsecchi, Robbert van Putten, Tor Maes, Mikko Muuronen, Natalia Dyubankova, Laurent Lefort and Evgeny A. Pidko

Bipolar membranes for intrinsically stable and scalable CO2 electrolysis

The energy transition requires technology to supply sustainable carbon-based chemicals for hard-to-abate sectors such as long-distance transport and plastic manufacturing. These necessary hydrocarbon chemicals and fuels, responsible for 10-20% of the global greenhouse gas emissions, can be produced sustainably by the electrolysis of captured CO 2 using renewable electricity. Currently, the state-of-the-art CO 2 electrolyzers employ anion exchange membranes (AEMs) to facilitate the transport of hydroxide ions from the cathode to the anode. However, CO 2 is crossing the membrane as well, resulting in a loss of reactant and unfavourable anode conditions which necessitates the use of scarce anode materials. Bipolar membranes (BPMs) offer an alternative that addresses the problem of CO 2 crossover but still requires research to match the product selectivity of AEM-based systems. Our perspective, a collaboration between groups of David Vermaas, Tom Burdyny and Marc Koper, published in Nature Energy, assesses the potential of BPMs for CO 2 electrolysis by looking at CO 2 utilization, energy consumption, and strategies to improve the product selectivity. Abstract CO 2 electrolysis allows the sustainable production of carbon-based fuels and chemicals. However, state-of-the-art CO 2 electrolysers employing anion exchange membranes (AEMs) suffer from (bi)carbonate crossover, causing low CO 2 utilization and limiting anode choices to those based on precious metals. Here we argue that bipolar membranes (BPMs) could become the primary option for intrinsically stable and efficient CO 2 electrolysis without the use of scarce metals. Although both reverse- and forward-bias BPMs can inhibit CO 2 crossover, forward-bias BPMs fail to solve the rare-earth metals requirement at the anode. Unfortunately, reverse-bias BPM systems presently exhibit comparatively lower Faradaic efficiencies and higher cell voltages than AEM-based systems. We argue that these performance challenges can be overcome by focusing research on optimizing the catalyst, reaction microenvironment and alkali cation availability. Furthermore, BPMs can be improved by using thinner layers and a suitable water dissociation catalyst, thus alleviating core remaining challenges in CO 2 electrolysis to bring this technology to the industrial scale. Go to the publication Kostadin Petrov Christel Koopman David Vermaas Tom Burdyny Siddharta Subramanian

Half Height Horizontal

NWO financiering voor flexibele stroomvraag van elektrisch gedreven industrie

NWO financiert twee projecten waarin onderzoek gaat plaatsvinden hoe de stroomvraag van de industrie flexibel gemaakt kan worden. Daarmee sluit het beter aan op het toekomstige energieaanbod. Een van de consortiumprojecten: ‘DEFLAME’ wordt geleid door Machteld van den Broek van de TU Delft. Zon en wind leveren een variabele hoeveelheid stroom, toch vraagt de huidige industrie een vrij constant vermogen. Om de industrie voor te bereiden op een stroomaanbod met veel zon en wind zijn aanpassingen nodig. Het gaat om zowel technische, economische als sociale aanpassingen die gezamenlijk door kennisinstellingen en bedrijfsleven worden onderzocht in deze twee projecten. Ook is er aandacht voor de drempels die aanpassingen in de weg staan. Over DEFLAME DEFLAME staat voor Direct Electrification of industrial heat demand supported by FLexibility At Multiple levels and their Exchanges (DEFLAME). Het project streeft ernaar de Nederlandse procesindustrie, en dan met name de chemische en voedselindustrie, veerkrachtiger en klimaatneutraal te maken door industriële warmte te elektrificeren met flexibiliteitopties. Van den Broek: ‘Hierbij kan je bijvoorbeeld denken aan het op- of afschakelen van installaties, opslag van warmte in de ondergrond en/of opslag van elektriciteit in batterijen, zodat de industrie beter kan inspelen op schommelingen in het energienetwerk.’ Dit vereist samenwerking op verschillende niveaus: technologie, fabrieken, clusters en nationale en internationale energiesystemen. DEFLAME richt zich op het wegnemen van obstakels voor de elektrificatie van lage temperatuur warmte (tot 400°C) met efficiënte technologie. ‘Dit wordt bij heel veel processen ingezet. Warmte is nodig om ervoor te zorgen dat de juiste chemische reacties plaatsvinden, maar ook bij het drogen, distilleren en verdampen is warmte nodig. In het kristallisatieproces om suiker te maken van bieten bijvoorbeeld, of bij de winning van zout’, legt Van den Broek uit. Bij kristallisatieprocessen kan bijvoorbeeld mechanische damprecompressie gebruikt worden. In dit proces worden de dampen door een elektrisch bediende compressor samengeperst en opnieuw gebruikt om de verdamper te verwarmen. ‘Dat bespaart energie, omdat je restwarmte gebruikt en de elektriciteit kan schoon worden opgewekt. Met zon en wind heb je, anders dan met gas, een variabel stroomaanbod. Als je de industrie wilt elektrificeren moeten bedrijven en de technologie daar flexibel op kunnen inspelen, door bijvoorbeeld als cluster warmte op te slaan of flexibiliteit in te bouwen in het elektriciteitssysteem.’ DEFLAME gaat vanuit verschillende niveaus en interdisciplinair strategieën en regelingen ontwikkelen om deze oplossingen mogelijk te maken. Van den Broek: “Ik kijk ernaar uit om samen met de partners een belangrijke stap te zetten om elektrificatie van de industrie in Nederland te bevorderen. Dit is een essentieel onderdeel van de energietransitie” Consortium partners Partners in het consortium zijn: AtlasCopco, Cosun, ISPT, Nobian, Oranje Wind Power II C.V./RWE, Smart Port, Stedin, Tennet, TNO, TU Delft en TU Eindhoven. Lees het NWO nieuwsbericht . Prof.dr.ir. M.A. (Machteld) van den Broek

Students Amos Yusuf, Mick Dam & Bas Brouwer winners of Mekel Prize 2024

Master students Amos Yusuf, from the ME faculty (Mick Dam, from the EEMCS faculty and graduate Bas Brouwer have won the Mekel Prize 2024 for the best extra scientific activity at TU Delft: the development of an initiative that brings master students into the classroom teaching sciences to the younger generations. The prize was ceremonially awarded by prof Tim van den Hagen on 13 November after the Van Hasselt Lecture at the Prinsenhof, Delft. They received a statue of Professor Jan Mekel and 1.500,- to spend on their project. Insights into climate change are being openly doubted. Funding for important educational efforts and research are being withdrawn. Short clips – so called “reels” – on Youtube and TikTok threaten to simplify complex political and social problems. AI fakes befuddle what is true and what is not. The voices of science that contribute to those discussion with modesty, careful argument and scepticism, are drowned in noise. This poses a threat for universities like TU Delft, who strive to increase student numbers, who benefit from diverse student populations and aim to pass on their knowledge and scientific virtues to the next generation. It is, therefore, alarming that student enrolments to Bachelor and Master Programs at TU Delft have declined in the past year. Students in front of the class The project is aimed to make the sciences more appealing to the next generation. They have identified the problem that students tend miss out on the opportunity of entering a higher education trajectory in the Beta sciences – because they have a wrong picture of such education. In their mind, they depict it as boring and dry. In his pilot lecture at the Stanislas VMBO in Delft, Amos Yusuf has successfully challenged this image. He shared his enthusiasm for the field of robotics and presented himself as a positive role model to the pupils. And in return the excitement of the high school students is palpable in the videos and pictures from the day. The spark of science fills their eyes. Bas Brouwer Mick Dam are the founders of NUVO – the platform that facilitates the engagement of Master Students in high school education in Delft Their efforts offer TU Delft Master Students a valuable learning moment: By sharing insights from their fields with pupils at high school in an educational setting, our students can find identify their own misunderstandings of their subject, learn to speak in front of non-scientific audiences and peak into education as a work field they themselves might not have considered. An extraordinary commitment According to the Mekel jury, the project scored well on all the criteria (risk mitigation, inclusiveness, transparency and societal relevance). However, it was the extraordinary commitment of Amos who was fully immersed during his Master Project and the efforts of Brouwer and Dam that brought together teaching and research which is integral to academic culture that made the project stand out. About the Mekel Prize The Mekel Prize will be awarded to the most socially responsible research project or extra-scientific activity (e.g. founding of an NGO or organization, an initiative or realization of an event or other impactful project) by an employee or group of employees of TU Delft – projects that showcase in an outstanding fashion that they have been committed from the beginning to relevant moral and societal values and have been aware of and tried to mitigate as much as possible in innovative ways the risks involved in their research. The award recognizes such efforts and wants to encourage the responsible development of science and technology at TU Delft in the future. For furthermore information About the project: https://www.de-nuvo.nl/video-robotica-pilot/ About the Mekel Prize: https://www.tudelft.nl/en/tpm/our-faculty/departments/values-technology-and-innovation/sections/ethics-philosophy-of-technology/mekel-prize

New catheter technology promises safer and more efficient treatment of blood vessels

Each year, more than 200 million catheters are used worldwide to treat vascular diseases, including heart disease and artery stenosis. When navigating into blood vessels, friction between the catheter and the vessel wall can cause major complications. With a new innovative catheter technology, Mostafa Atalla and colleagues can change the friction from having grip to completely slippery with the flick of a switch. Their design improves the safety and efficiency of endovascular procedures. The findings have been published in IEEE. Catheter with variable friction The prototype of the new catheter features advanced friction control modules to precisely control the friction between the catheter and the vessel wall. The friction is modulated via ultrasonic vibrations, which overpressure the thin fluid layer. This innovative variable friction technology makes it possible to switch between low friction for smooth navigation through the vessel and high friction for optimal stability during the procedure. In a proof-of-concept, Atalla and his team show that the prototype significantly reduces friction, averaging 60% on rigid surfaces and 11% on soft surfaces. Experiments on animal aortic tissue confirm the promising results of this technology and its potential for medical applications. Fully assembled catheters The researchers tested the prototype during friction experiments on different tissue types. They are also investigating how the technology can be applied to other procedures, such as bowel interventions. More information Publicatie DOI : 10.1109/TMRB.2024.3464672 Toward Variable-Friction Catheters Using Ultrasonic Lubrication | IEEE Journals & Magazine | IEEE Xplore Mostafa Atalla: m.a.a.atalla@tudelft.nl Aimee Sakes: a.sakes@tudelft.nl Michaël Wiertlewski: m.wiertlewski@tudelft.nl Would you like to know more and/or attend a demonstration of the prototype please contact me: Fien Bosman, press officer Health TU Delft: f.j.bosman@tudelft.nl/ 0624953733

Een flexibele backstop als deel van de oplossing voor netcongestie

Uit naam van het TU Delft PowerWeb Institute overhandigen onderzoekers Kenneth Brunninx en Simon Tindemans op 12 november 2024 een Position Paper aan de Tweede Kamer, met een mogelijke oplossing voor de grote netwerkcapaciteit-problemen die in Nederland steeds vaker opspelen. Waarschijnlijk haalt Nederland de klimaatdoelen 2030 niet, en dat komt onder andere doordat de grote industrie niet snel genoeg kan overstappen op elektriciteit, mede doordat er steeds vaker problemen ontstaan rondom netwerkcapaciteit en netcongestie. Naar alle waarschijnlijk zullen die problemen dit decennium eerst zelfs toenemen, voordat ze kunnen afnemen, stellen de onderzoekers. De oplossing die de onderzoekers van het TU Delft PowerWeb Institute aanbieden, is de ‘flexibele backstop’. Met een flexibele backstop kan de huidige capaciteit van het elektriciteitsnet efficiënter gebruikt worden zonder aan veiligheid of betrouwbaarheid in te boeten. Een flexibele backstop is een veiligheidsmechanisme dat semiautomatisch en op korte termijn de hoeveelheid elektriciteit vermindert die een elektrische verbruiker van het elektriciteitsnet kan onttrekken (een elektrische laadpaal of een warmtepomp) of leveren (een PV-installatie). Het is een klein apparaatje dat is aangesloten of ingebouwd in een elektrische verbruiker, zoals een laadpaal of warmtepomp, en dat ‘communiceert’ met de distributienetwerkbeheerder. In geval van acute congestie op het netwerk geeft de netwerkbeheerder een signaal aan het apparaat om de hoeveelheid stroom te beperken. Duitsland heeft recent een vergelijkbaar systeem ingevoerd voor elektrische laadpalen. De backstop wordt enkel geactiveerd in periodes van acute congestieproblemen, nadat alle andere maatregelen uitgeput zijn. “Het opwaarderen van het elektriciteitsnetwerk blijft essentieel, maar zal in de praktijk nog jaren duren. Er is dus behoefte aan kortetermijnoplossingen die geïntegreerd kunnen worden in de langetermijnplanning. Wij, de leden van het TU Delft PowerWeb Institute, roepen de overheid, netwerkbeheerders en regulator op om de flexibele backstop als extra veiligheidsmaatregel voor het netwerk te onderzoeken”, aldus de onderzoekers. Het gehele paper is hier te lezen. Kenneth Bruninx is universiteit hoofddocent bij de faculteit Techniek, Bestuur en Management, waar hij met kwantitatieve modellen energiebeleid, regulering en marktontwerp evalueert. Simon Tindemans is universitair hoofddocent in de Intelligent Electrical Power Grids groep van faculteit Elektrotechniek, Wiskunde en Informatica. Hij doet onder andere onderzoek naar onzekerheid en risicomanagement voor elektriciteitsnetwerken. Het TU Delft PowerWeb Institute ontwerpt het elektriciteitsnetwerk van de toekomst.

25 year celebration of formal collaboration between Delft University of Technology and the University of Campinas

On 25 October 2024 we celebrated 25 years of formal collaboration between Delft University of Technology and the University of Campinas. What began as a project to exchange some students in chemical engineering has now grown to a multifaceted and broad academic collaboration which accumulated into 24 joint research projects (>20 M Euro); 16 advanced courses and 15 Doctors with a Dual Degree PhD. Patricia Osseweijer, TU Delft Ambassador Brazil explained, “We are proud to show and reflect on this special day the added value we created resulting from our joint activities. The lessons we learned demonstrate that especially continuity of funds and availability for exchanges has contributed to joint motivation and building trust which created strong relations. This is the foundation for academic creativity and high-level achievements.” The program presented showcases of Dual Degree projects; research activities and education. It discussed the future objectives and new fields of attention and agree on the next steps to maintain and strengthen the foundation of strong relations. Telma Franco, Professor UNICAMP shared that “joint education and research has substantially benefitted the students, we see that back in the jobs they landed in,” while UNICAMP’s Professor Gustavo Paim Valenca confirmed that “we are keen to extend our collaboration to more engineering disciplines to contribute jointly to global challenges” Luuk van der Wielen highlighted that “UNICAMP and TU Delft provide valuable complementary expertise as well as infrastructures to accelerate research and innovation. Especially our joint efforts in public private partnerships brings great assets” To ensure our future activities both University Boards have launched a unique joint program for international academic leadership. This unique 7-month program will accommodate 12 young professors, 6 from each university. The programme began on 4 November 2024 in Delft, The Netherlands.