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Karlsruhe Institute of Technology (KIT)

Karlsruhe Institute of Technology (KIT)

40 Projects, page 1 of 8
  • Funder: UK Research and Innovation Project Code: EP/V034154/1
    Funder Contribution: 1,151,140 GBP

    Liquid infused surfaces (LIS) are a novel class of surfaces inspired by nature (pitcher plants) that repel any kind of liquid. LIS are constructed by impregnating rough, porous or textured surfaces with wetting lubricants, thereby conferring them advantageous surface properties including self-cleaning, anti-fouling, and enhanced heat transfer. These functional surfaces have the potential to solve a wide range of societal, environmental and industrial challenges. Examples range from household food waste, where more than 20% is due to packaging and residues; to mitigating heat exchanger fouling, estimated to be responsible for 2.5% of worldwide CO2 emissions. Despite their significant potential, however, to date LIS coatings are not yet viable in practice for the vast majority of applications due to their lack of robustness and durability. At a fundamental level, the presence of the lubricant gives rise to a novel but poorly understood class of wetting phenomena due to the rich interplay between the thin lubricant film dynamics and the macroscopic drop dynamics, such as an effective long-range interaction between droplets and delayed coalescence. It also leads to numerous open challenges unique to LIS, such as performance degradation due to lubricant depletion. Integral to this EPSRC Fellowship project is an innovative numerical approach based on the Lattice Boltzmann method (LBM) to solve the equations of motion for the fluids. A key advantage of LBM is that key coarse-grained molecular information can be incorporated into the description of interfacial phenomena, while remaining computationally tractable to study the macroscopic flow dynamics relevant for LIS. LBM is also highly flexible to account for changes in the interface shape and topology, complex surface geometry, and it is well-suited for high performance computing. The developed simulation framework will be the first that can fully address the complexity of wetting dynamics on LIS, and the code will be made available open source through OpenLB. Harnessing the LBM simulations and supported by experimental data from four project partners, I will provide the much-needed step change in our understanding of LIS. The expected outcomes include: (i) design criteria that minimise lubricant depletion, considered the main weakness of LIS; (ii) new insights into droplet and lubricant meniscus dynamics on LIS across a wide range of lubricant availability and wettability conditions; and (iii) quantitative models for droplet interactions on LIS mediated by the lubricant. These key challenges are shared by the majority, if not all, of LIS applications. Addressing them is the only way forward to better engineer the design of LIS. Finally, the computational tools and fundamental insights developed in the project will be exploited to explore two potentially disruptive technologies based on LIS, which are highly relevant for the energy-water-environment nexus in sustainable development. First, I will investigate application in carbon capture, exploiting how liquids can be immobilised in LIS with a large surface to volume ratio, in collaboration with ExxonMobil. More specifically, liquid amine-based CO2 capture is an important and commercially practised method, but the costly infrastructure and operation prohibit its widespread implementation. Excitingly, LIS may provide a solution to a more economical carbon capture method using liquid amine. Second, motivated by the current gap of 47% in global water supply and demand, as well as environmental pressure to reduce the use of surfactants, I will examine new approaches to clean in collaboration with Procter & Gamble. The key idea is to induce dewetting of unwanted liquid droplets on solid surfaces using a thin film of formulation liquid, thus introducing wettability alteration more locally and using much reduced resources.

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  • Funder: UK Research and Innovation Project Code: NE/X00452X/1
    Funder Contribution: 1,938,800 GBP

    With the Kigali Amendment coming into force in 2019, the Montreal Protocol on Substances that Deplete the Ozone Layer has entered a major new phase in which the production and use of hydrofluorocarbons (HFCs) will be controlled in most major economies. This landmark achievement will enhance the Protocol's already-substantial benefits to climate, in addition to its success in protecting the ozone layer. However, recent scientific advances have shown that challenges lie ahead for the Montreal Protocol, due to the newly discovered production of ozone-depleting substances (ODS) thought to be phased-out, rapid growth of ozone-depleting compounds not controlled under the Protocol, and the potential for damaging impacts of halocarbon degradation products. This proposal tackles the most urgent scientific questions surrounding these challenges by combining state-of-the-art techniques in atmospheric measurements, laboratory experiments and advanced numerical modelling. We will: 1) significantly expand atmospheric measurement coverage to better understand the global distribution of halocarbon emissions and to identify previously unknown atmospheric trends, 2) combine industry models and atmospheric data to improve our understanding of the relationship between production (the quantity controlled under the Protocol), "banks" of halocarbons stored in buildings and products, and emissions to the atmosphere, 3) determine recent and likely future trends of unregulated, short-lived halocarbons, and implications for the timescale of recovery of the ozone layer, 4) explore the complex atmospheric chemistry of the newest generation of halocarbons and determine whether breakdown products have the potential to contribute to climate change or lead to unforeseen negative environmental consequences, 5) better quantify the influence of halocarbons on climate and refine the climate- and ozone-depletion-related metrics used to compare the effects of halocarbons in international agreements and in the design of possible mitigation strategies. This work will be carried out by a consortium of leaders in the field of halocarbon research, who have an extensive track record of contributing to Montreal Protocol bodies and the Intergovernmental Panel on Climate Change, ensuring lasting impact of the new developments that will be made.

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  • Funder: UK Research and Innovation Project Code: EP/V011863/1
    Funder Contribution: 4,436,400 GBP

    The UK chemical sector has an annual turnover of over £32 billion with 99,000 direct jobs in 2016. The Centre's vision is to transform the UK's chemical industry into a fossil-independent, climate-positive and environmentally-friendly circular chemical economy. The overall novelty of our programme is the development of a sector-wide solution with deep circularity interventions, by creating a circular resources flow of olefin-the raw material for 70% of all organic chemical production. Our whole system approach will include key sectors of production, transportation/distribution, refinery/downstream, use and waste recycling, to reduce fossil reliance and improve productivity and sustainability of the whole process industry. The Centre will generate a cross-disciplinary platform combining synergistic innovations in science/engineering with social scientists to comprehend the whole system industrial symbiosis and market/policy/incentive design. The Core Research Programme is organised around three interconnected themes: (1) Key technologies to enable olefin production from alternative/recycling wastes streams and design more reusable chemicals via advanced catalytic processes; (2) Process integration, whole system analysis and value chain evaluation, and (3) Policy, society and finance. Through detailed process modelling, economic analysis and environmental assessment of technology solutions along the supply chain, accelerated understanding, opportunities and optimum solutions to achieve circularity of olefin-derived resources flow will be attained. These activities are embedded with stakeholders involving all affected groups, including local SMEs and downstream users, and will provide evidence and data for policymakers. The Centre will engage with users through social studies and organised events, and exploit consumer/business behavioural change related to chemical systems enabling a sustainable community and society with innovative technologies.

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  • Funder: UK Research and Innovation Project Code: EP/S01702X/1
    Funder Contribution: 7,226,660 GBP

    In order to meet the UK's carbon reduction targets, and achieve an energy mix that produces less CO2, we must continue to investigate ways in which to make nuclear power cleaner, cheaper and safer. At the same time, as new reactors such as Hinkley Point C are built, the UK needs to develop the work force who will operate, regulate and solve technical problems in civil nuclear power, in order to capitalise on our investment in nuclear energy. Important in this respect is that the UK currently operates mainly old advanced gas-cooled reactors, fundamentally different from the next fleet of UK nuclear power stations, which will be light-water reactors. Key to this change, in terms of this research project, is that Zirconium is a preferred fuel cladding material in LWRs. A major part of a nuclear reactor is the fuel assembly - the structure that encapsulates the highly radioactive nuclear fuel. Understanding the performance of the materials used to make these assemblies is critical for safe, efficient operation, and they must be able to maintain their structure during normal operation, handling and storage, as well as survive in the unlikely event of an accident, when they become crucial in preventing the escape of radioactive materials. Because of the need to operate nuclear reactors as safely as possible, fuel is often removed well before it is spent, as we currently do not know enough about fuel assembly materials, so must adopt a highly cautious, safety-first approach. This does mean, however, that it is more costly to run a reactor, as assemblies must be replaced well before all the fuel is consumed, and this also means the assembly then - prematurely - becomes additional nuclear waste, which must be safely handed and stored, at further high cost. By gaining greater understanding of how assembly materials perform when irradiated, we will be able to make more accurate safety cases, which will mean that fuel assemblies can be used for longer periods without additional risk. Such knowledge will enable the UK to operate the next generation of reactors far more efficiently, significantly reducing the cost of nuclear power. This is particularly important now, given that the UK is going to have light-water, instead of advanced gas-cooled, reactors, and with it the fuel assembly and its material will change very fundamentally. This research effort will also significantly benefit other countries using nuclear energy, which will establish the UK as a centre of expertise in the area. This will further attract inward investment in research and development in the UK, creating future wealth and employment alongside cleaner energy. A second key theme of the project will be to explore the use of zirconium alloys in critical components for future fusion reactors. The UK has a leading position in defining the materials that will be chosen for the ITER and DEMO international fusion projects, and this theme will contribute to maintaining the UK's reputation as a centre of excellence in fusion research.

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  • Funder: UK Research and Innovation Project Code: EP/J003387/1
    Funder Contribution: 214,382 GBP

    When solid materials are loaded above a critical level, they may change their shape permanently: they undergo plastic deformation. Consider, for example, a cylinder which we compress by pushing from top to bottom. If the load is small, the cylinder first deforms elastically (it reverts to its original shape after the load is removed). Above a certain load, some permanent deformation remains. Now if we use a macroscopic cylinder, say, several centimetres in size, then the stress (the force per unit area) needed to obtain a given relative deformation will not depend on the size of the cylinder. It will increase gradually with increasing deformation, and this 'hardening behavior' will be identical for cylinders made of the same material and deformed under the same conditions. If the stress is everywhere the same in the cylinder, also the deformation will be homogeneous - the cylinder will get shorter and thicker but will retain its cylindrical shape. But when the deforming body becomes very small - of the order of a few micrometers in diameter - then we observe quite different behavior: (1) The stress required to deform samples of material increases as the samples become smaller. (2) Even if the stress is increased slowly and steadily, the deformation does not increase gradually but in large jumps. These jumps occur randomly, and lead to large deformations in small parts of the sample. As a consequence, in our cylinder example the samples assume irregular accordeon-like shapes. If we bend very thin wires, they may not deform into smoothly curved but into random shapes resembling mis-shapen paperclips. (3) Even if the material properties are the same (for instance, if all our cylinders have been machined out of the same block) the stresses required to deform samples may scatter hugely. In two apparently identical micrometer sized samples, the stresses required to initiate or sustain plastic deformation may easily differ by a factor of two. Obviously this poses serious problems if we want to avoid or control irreversible deformation in very small components. The first of these aspects have been studied in some detail, and some work has also been done on the second one. However, there is no systematic study which quantifies the scatter in deformation behaviour between different small samples and provides tools for assessing the risk of unwanted deformation behaviour. We have teamed up with German researchers who conduct micro-deformation experiments and with others who simulate such deformation processes by tracing the motion of material defects which produces the irreversible deformation. Together we will conduct and analyze large series of experiments and simulations to characterize the scatter in deformation behaviour and to understand how it depends on sample size, material preparation, and method of deformation. We will then use this database to develop simulation tools that allow engineers to assess the risk of undesirable outcomes. Why is it important? Imagine you want to bend sheets of metal with a size of centimetres to meters, say for making them into cylinders for producing cans, or for making car doors. It is comparatively easy to get the desired shapes. However, if you try to do the same on a very small scale, the result might look quite different! Micro-scale scatter of deformation properties may affect our ability to form materials into very small shapes and to produce very small parts for microtechnologies. A striking example are the very thin wires that provide electrical connections for microchips. If the shape of these wires scatters too much, two of them may get into contact and produce a short-circuit that makes the device useless. As miniaturization of components and devices proceeds, we need to gain the knowledge and expertise needed to handle forming processes on the microscale. Our research wants to make a contribution to this purpose.

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