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Discover the stories of researchers at the
Faculty of Mechanical Engineering.

Hydrogen as the key to a sustainable shipping sector

Sustainability targets for the transport sector are not limited to only road transport. The shipping industry has decided to explore that issue now too. And though CO2 emissions per transported container could be worse, ships are undeniably a considerable source of unwanted emissions, from NOx to particulate matter. TU Delft researcher and former marine officer Klaas Visser believes there are excellent opportunities to change this.

Fluid mechanics for the future

Fluid mechanics are integral to many areas of our everyday life including sport, medicine, climate change and environmental issues as well as the more traditional fields of transport, energy and building infrastructure. For instance, Dr Jerry Westerweel, professor of Fluid Mechanics, has been involved in a fluid mechanics project as part of an investigation into swimming techniques.

Sustainable medical instruments for developing countries

Sterilisation has been the most common method of birth control for women in India since the 1970s. According to the country’s national authorities, India needs to keep population growth under control, otherwise it risks overtaking China, currently the most populous country in the world, by 2028. Though there is severe criticism of this sterilisation policy (after all, there are less drastic ways of getting people to have fewer children, and on top of that India’s birth rate is already decreasing as a result of increased prosperity), more than one in three women are being sterilised at the moment. Often with fatal consequences.

TU Delft ready to unleash the beast

Maintenance costs are a nightmare for every ship owner, according to Mirek Kaminski, professor of ship and offshore structures in the Department of Maritime and Transport Technology at TU Delft (3mE). In his perfect future, ships are more sustainable, more effective and more affordable. The hexapod is a unique test facility for this.

The paint reveals the master

In the end, even the most famous painting is just paint on a canvas, says art historian Joris Dik. Studying the paint can expose forgeries, magically conjure up hidden paintings, and allow you to eavesdrop while a Rembrandt or a Picasso practices his craft. ‘Da Vinci did not paint the shadows in the Mona Lisa’s face with a darker hue, but by stacking layers of almost transparent paint,’ explains Joris Dik, professor of materials in art and archaeology at TU Delft. Dik is an art historian, but also a materials scientist. A proponent of the arts in the world of science, but he feels completely at home there. ‘In art, it often revolves around the concept, the image, the idea and the beauty of a painting. In fact, many art enthusiasts actually find technical knowledge disconcerting. That has always surprised me. Because it’s the material that provides us with great insight into the creative process.’ In the past decade, Dik has made a name for himself by introducing the art world to X-ray fluorescence spectroscopy. ‘XRF’ can ‘dissect’ a painting without damaging it. The analysis technique individually reveals different chemical elements in the paint, often pigments. It turns out there is a woman’s face resembling the potato eaters hidden behind Van Gogh’s painting Pasture in Bloom (1887), for example. Van Gogh painted over it because canvasses were expensive. Rembrandts Saul and David (ca. 1660) appears to have been simply cut in half, Dik reveals. ‘Perhaps the paintings earned more money if sold separately?’ Saul and David were reunited, but XRF research has shown that they probably shifted a few millimetres from their original position vis-à-vis each other. ‘Every major museum has its own scanner now,’ Dik says. Nowadays they are important to confirm the authenticity of old masters. ‘Last year another forged Frans Hals was discovered.’ It concerned the painting Portrait of a Gentleman , sold by Sotheby’s for almost ten million euros in 2011. The canvas had surfaced in 2008 and after many art experts examined the painting, it was attributed to Frans Hals based on the typical brush strokes, the composition and the paint that was used. Your own synchrotron Painting research can be conducted with much greater precision with synchrotron radiation, emphasises Dik. ‘It enables you to see exactly where the elements are in a layer of paint. It also provides you with depth, a 3D image. Moreover, you can look at many more elements.’ Dik has already travelled once with a painting to the particle accelerator in Geneva, which generates high-quality synchrotron radiation. ‘But the measuring time is limited, of course. And you don’t want drag around valuable paintings too often.’ In two or three years Dik hopes to have a mobile ‘mini-synchrotron’ at his disposal. Dutch physicists from Eindhoven and Delft are building one, with the support of KNAW in a large research consortium called Smart*Light. The most important applications are in materials science and health care, but Dik is participating as well. ‘Art history is a small field and the world of art a small market. So I have to persuade technologists from completely different scientific disciplines that we’re an interesting niche for the new research technique.’ That’s why he appears regularly on TV. Dik is one of the experts in the popular television series and touring theatre show ‘Het geheim van de meester’ (‘The secret of the master’). And he can be frequently seen on shows such as DWDD, Pauw and RTL Night to talk about the authenticity of paintings. ‘It’s not that I have an urge to be on TV, but as an art historian you’re not building dikes or inventing new medicines, which are things everyone immediately sees the need for. You really have to continue explaining the importance of art history and promoting you work.’ Copyright photo's: Geheim van de Meester When Smart*Light is ready, Dik would like to study Pablo Picasso’s c ubist painting The Old Guitarist . There appear to be several versions beneath it, each possibly more abstract. If you can manage to ‘peel off’ these layers, then you can follow Picasso’s thoughts. ‘Essentially, you’re eavesdropping on one of the greatest innovators of painting,’ Dik says. Palimpsests are on Dik’s wish list as well. These are written parchments from the early Middle Ages, before the age of paper. The valuable, dried animal skins were scraped off multiple times in order to be written on again. ‘The university library in Leiden has a 32-page-long palimpsest that has visible text underneath it,’ Dik says. ‘But it’s too vague to decipher.’ Dik hopes to make the text visible with the Smart*Light by zooming in on a specific element. ‘Who knows, this may lead to us discovering the oldest Dutch text.’ Strange partners Dik is always in search of new alliances and new analyse techniques. For example, he is currently studying the use of optical coherence tomography (OCT) with Jeroen Kalkman. OCT is an infrared technique that’s making deviations in the retina visible in increasing detail. ‘An OCT scan enables you to make a kind of cross-section of the retina. We use it to study layers of varnish. For example to monitor with great precision the removal of a layer of varnish during a restoration. More and more, restoration studios are resembling surgery theatres.’ Dik has also discovered common interests with the Netherlands Forensic Institute (NFI). ‘There are important parallels between art history and forensic research. A forensic investigator is often given objects and asked to explain what happened to them.’ The NFI discovered that XRF is a good way to reveal traces of blood or sperm when the usual UV techniques fail, for example on a deep-black background. And XRF can also reveal traces of gunpowder that have been ‘washed out’ or that are hidden behind a fresh layer of paint. In collaboration with the printing company Océ 3D, Diks’ research group printed a number of old paintings . The Jewish Bride by Rembrandt now graces a wall in the ME building at TU Delft. The copy is much more ‘real’ than a poster. The bottom layer was printed in plastic and provides the copy with relief and thick brush strokes and craquelé . ‘The red of the dress is not deep enough,’ the connoisseur Dik points out. ‘We haven’t managed to imitate the colour well, because that also depends on certain pigments in the bottom layer.’ But it’s the lustre that really betrays the fact that it’s a fake, in Dik’s opinion. ‘The lustre has the same height everywhere, whereas it varies in the real painting. A PhD candidate is currently studying the differences in lustre in layers of varnish, and how they affect paintings.’ What needs to be done to make a more realistic 3D copy? ‘More than anything, we want to learn more. How quickly do layers of varnish discolour? How fast does such a layer wear away and how does the lustre change as time passes? And a print enables you to create an image of the effect of a restoration. Make no mistake, discussions about what is really original and whether it should be restored can be extremely heated in the world of art. So we can contribute by giving an idea of the result.’ Who is Joris Dik? His grandfather and uncle restored old paintings. The craft, the studio and the smell of oil paint fascinated Joris Dik (1974). He was well on his way to continuing the family tradition while he studied art history. But during an internship at the J. Paul Getty Museum (Los Angeles), Dik discovered that it was especially the preliminary research preceding restoration that captivated him. Which pigments did the painter use? Have they discoloured? Were any changes ever made to the painting? If so, when and why? He followed up his education with PhD research on Naples yellow. ‘The oldest pigment in the history of art. It can be found on all of the tiles in India from four thousand BC.’ Dik took samples from artworks from different times and places and analysed the composition. This created a ‘historical atlas’ of Naples yellow that helps during restorations and investigations to determine authenticity. In 2003 he started working as a materials researcher at TU Delft. He has been Antoni van Leeuwenhoek professor since 2010.

Wind turbine farms can generate much more energy

In order to generate more sustainable energy and reduce our dependence on fossil fuels, an increasing number of wind turbines are appearing on the horizon. Especially in the sea, because they are not in anyone’s way there and more importantly there is simply much more space there. And there is another advantage: whereas once upon a time wind turbines were neatly lined up in farms, since 2030 they have become floating farms with a dynamic setup.

New grab unloads vessels faster and smarter

There was plenty of reason to celebrate for transport technologist Dingena Schott and her team at TU Delft. Not only did they develop a design method for a new grab, but the grab, built by Nemag, complied with all of the predictions generated by the models, tests and simulations that they validated. ‘There is no precedent for this in the scientific literature. It’s definitely the crowning glory of our work,’ says Schott. This Dutch grab could potentially unload vessels in ports all over the world more efficiently and sustainably. Dingena Schott Every day, huge vessels from Brazil and Australia enter the port of Rotterdam with thousands of tons of iron ore, coal and other dry bulk. Here, crane operators ensure that the cargo is emptied quickly and efficiently, so that it can be stored or distributed to smaller vessels that then transport it via the Rhine to steel factories in Germany and Austria. To unload this kind of cargo, a crane operator has a variety of grabs to choose from, depending on the kind of dry bulk. ‘The question is: do they have the ideal grab for the product they want to unload?’ says Dingena Schott, who is doing research at the Department of Maritime and Transport Technology at the ME Faculty on new technologies for port-related transport logistics. ‘The most recent design for grabs is approximately fifty years old. Since that time, no fundamentally new designs have come onto the market.’ So does this mean vessels can be unloaded more quickly so that they can leave the port earlier to pick up the next load? Video created by Stef Lommen Schott thinks so. What’s more, the research that she and her team conducted has already led to an innovative grab that reduces the unloading time of a vessel by at least ten per cent. TU Delft developed the models, the insight and the design method for this, and worked together with grab manufacturer Nemag from Zierikzee, which created the new design. On 13 November, Nemag even received a prestigious award, a prize given by the International Bulk Journal for the most innovative technology for cargo handling. At first sight, the new grab doesn’t seem that much different than existing grabs. All grabs have two shells with a hinge in the middle and a closing mechanism. ‘The aim is to get as much material as possible per grab,’ says Schott. ‘The amount is limited by the crane on the quay, which can only lift up to a certain weight. If you go for a really heavy grab, then it will of course penetrate deeper into the materials, but it can’t take as much per grab. So the ideal grab is as light as possible but can still dig itself in well. It’s kind of a trade-off between mass and force.’ But where do you start when you want to improve a trusted grab in the conservative world of handling and storing bulk? ‘Since 2007, we have been using discrete element software as part of an innovative design method. Since the arrival of this technique, we have been able to understand for the first time exactly what happens when materials are grabbed. It makes it possible for us to model iron ore pellets as well as the grab, monitor their behaviour in a simulation when the pellets are grabbed, and thus determine whether the grab is being filled optimally. Initially we modelled and tested with an existing grab at Tata Steel in Ijmuiden in order to validate the model.’ Thanks to the software, Schott and her team can compute exactly how much force is needed to grab as many pellets of iron ore as possible. ‘In order to be able to move the grab you have to pull the cables at the top. Then the grab tries to close, but because of the resistance of the iron ore, it will become slower and slower. To maintain the same speed, you then have to pull harder on the cables,’ says Schott. To understand the dynamics of the grab together with the iron ore properly, she connected the dynamic grab model to the discrete element model. The difference between the existing and the new grab is in the overall design: both the new mechanism and the new shape of the shell ensure that the ratio between the forces exerted and the filling of the grab is optimised. That’s what ultimately makes it possible to unload a vessel in ten per cent less time. It’s already a considerable improvement in efficiency. In addition to the productivity, which has increased by 10 per cent, the grab also weighs 15 per cent less. As a result, fewer scarce raw materials are needed. Moreover, vessels don’t stay in port as long waiting and unloading, which reduces emissions. But it could be even more effective. Schott’s aim is to speed up the unloading process even more in the future by creating a dynamic grab capable of adapting itself. Moreover, it’s not just about the grab, but also the crane onto which the grab and cables are attached. ‘We only changed the grab design now, because we couldn’t change anything at the top of the crane yet,’ says Schott. ‘But actually we shouldn’t only be perfecting the grab, but also its interaction with the crane.’ Currently a PhD student is developing models for other kinds of bulk materials. The properties of a material, such as the shape of the particles, their texture and stiffness, mean that each material ‘behaves’ differently. This affects the flow inside the grab. Think, for example, of dry sand, which flows more easily than wet sand. ‘By analysing all kinds of substances, we can develop the grab even further. Ultimately, of course, we want a grab that performs optimally for all products and under all conditions.’ Read the press release by Nemag: 'Nemag wins the prestigious IBJ Award with the nemaX®