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Stuttgart University

Country: Germany

Stuttgart University

16 Projects, page 1 of 4
  • Funder: UK Research and Innovation Project Code: EP/W014378/1
    Funder Contribution: 682,674 GBP

    Catalysis is a key area of fundamental science which underpins a high proportion of manufacturing industry. Developments in catalytic science and technology will also be essential in achieving energy and environmental sustainability. Progress in catalytic science requires a detailed understanding of processes at the molecular level, in which computation now plays a vital role. When used in conjunction with experiment, computational modelling is able to characterise structures, properties and processes including active site structures, reaction mechanisms and increasingly reaction rates and product distributions. However, despite the power of computational catalysis, currently available methods have limitations in both accuracy and their ability to model the reaction environment. Also, it is practically difficult to model hybrid catalysts, which combine elements of different types of catalyst (e.g. unnatural metal centres incorporated in natural enzymes). Advances in technique are essential if the goal of catalysis by design is to be achieved. A powerful, practical approach to modelling catalytic processes is provided by Quantum Mechanical/Molecular Mechanical (QM/MM) methods, in which the reaction and surroundings are described using an accurate quantum mechanical approach, with the surrounding environment modelled by more approximate classical forcefields. QM/MM has been widely and successfully employed in modelling enzymatic reactions (recognised in the 2013 Nobel prize for Chemistry) but has an equally important role in other areas of catalytic science. The flagship ChemShell code, developed by the STFC team in collaboration with UCL, Bristol and other groups around the world, is a highly flexible and adaptable open source QM/MM software package which allows a range of codes and techniques to be used in the QM and MM regions (www.chemshell.org). The software has been widely and successfully used in modelling enzymatic reactions and catalytic processes in zeolites and on oxide surfaces. It will provide the ideal platform for the developments we are proposing which will take computational catalysis to the next level. These will include the use of high level QM techniques to achieve chemical accuracy, accurate modelling of solvent effects, calculation of spectroscopic signatures allowing direct interaction with experiment, and dynamical approaches for free energy simulations. Crucially, we will bring together methods from different spheres of computational catalysis to enable modelling of hybrid catalytic systems. We will develop flexible and rigorous methods that meet the twin challenges of high-level QM treatment for accuracy with the ability to sample dynamics of the reacting system. Together these methods will allow accurate and predictive modelling of catalytic reactions under realistic conditions. The project will also anticipate the software developments needed to exploit the next generation of exascale high performance computing. We will apply these new techniques to model the catalytic behaviour of a range of engineered heterogeneous, homogeneous and biomolecular catalysts, currently under study in the UK Catalysis Hub. The Hub supports experimental and computational applications across the whole UK catalysis community. This project will provide method development and software engineering that is not covered by the Hub, and thus will complement EPSRC investment in the Hub. Specific systems include methanol synthesis using homogeneous ruthenium complexes, Cu-based artificial enzymes for enantioselective Friedel-Crafts reactions, fluorophosphite-modified rhodium systems for hydroformylation catalysis of alkenes, and non-canonical substitutions in non-heme iron enzymes for C-H functionalisations. These highly topical and potentially industrially relevant systems will allow us both to test and exploit the new software, which promises a step change in our ability to model catalytic systems and reactions.

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  • Funder: UK Research and Innovation Project Code: EP/R001847/1
    Funder Contribution: 1,022,120 GBP

    Nitrogen compounds play a crucial role in the earth's ecosystems, being continually converted from one form to another as they pass from the atmosphere to living organisms on land and in the sea. Nitric oxide gas (NO), for example, is a key intermediate in the global nitrogen cycle, and plays important roles in many processes in almost all forms of life, often acting as a signalling molecule. However, emissions of NO and the toxic gas nitrogen dioxide (collectively known as NOx) from heavy industry and motor vehicles alter the composition of nitrogen compounds in the atmosphere and are highly damaging both directly and indirectly to the human respiratory system. The removal of NOx from exhaust emissions is a pressing environmental concern and an important target for industrial catalysis research, an area of extreme importance to the UK economy. We propose to study the chemistry of nitrogen oxides in biological and industrial environments where a full understanding of how the gases are controlled is crucial but still lacking. In both cases the chemistry is controlled by transition metals: cytochrome c' proteins have evolved an extraordinary degree of control of NO through binding to an iron complex which discriminates against other diatomic gases, while in zeolite catalysts (microporous aluminosilicate structures) NOx gases can be converted into safer by-products at copper centres through the addition of ammonia in a process known as selective catalytic reduction (SCR). The precise mechanisms, however, are not currently proven. We will investigate the chemistry of nitrogen dioxide and nitrogen oxide in both systems by computational simulations performed on high performance clusters. The resulting data will be used to model spectroscopic signatures, i.e. how electromagnetic radiation (such as light or X-rays) interacts with matter. These will be compared with the results of infrared, Raman, UV-visible and X-ray absorption experiments on the two systems to better understand the processes involved in the chemical reactions, which will inform the future design of improved zeolite catalysts and bioengineered proteins. We will use quantum mechanical/molecular mechanical (QM/MM) modelling to identify the reaction mechanisms and calculate spectroscopic signatures of the two systems. In this approach the zeolite and protein active sites will be treated using a highly accurate, but computationally expensive, quantum mechanical level of theory, embedded in an environment described by an efficient classical calculation. New QM/MM methods will be implemented that can enable larger QM regions to be calculated and more accurate spectroscopic signatures including anharmonic vibrational effects. Importantly, our approach for combining computational modelling with experimental results will be generally applicable to any chemical processes in complex systems, including other industrial catalysts and biomolecules.

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  • Funder: UK Research and Innovation Project Code: EP/P006930/1
    Funder Contribution: 10,456,200 GBP

    The vision of the Hub is to create ground-breaking embedded metrology and universal metrology informatics systems to be applied across the manufacturing value chain. This encompasses a paradigm shift in measurement technologies, embedded sensors/instrumentation and metrology solutions. A unified approach to creating new, scientifically-validated measurement technologies in manufacturing will lead to critical underpinning solutions to stimulate significant growth in the UK's productivity and facilitate future factories. Global manufacturing is evolving through disruptive technologies towards a goal of autonomous production, with manufacturing value-chains increasingly digitised. Future factories must be faster, more responsive and closer to customers as manufacturing is driven towards mass customisation of lower-cost products on demand. Metrology is crucial in underpinning quality, productivity and efficiency gains under these new manufacturing paradigms. The Advanced Metrology Hub brings together a multi-disciplinary team from Huddersfield with spokes at Loughborough, Bath and Sheffield universities, with fundamental support from NPL. Expertise in Engineering, Mathematics, Physics and Computer Science will address the grand challenges in advanced metrology and the Hub's vision through two key research themes and parallel platform activities: Theme I - Embedded Metrology will build sound technological foundations by bridging four formidable gaps in process- and component-embedded metrology. This covers: physical limits on the depth of field; high dynamic range measurement; real-time dynamic data acquisition in optical sensor/instruments; and robust, adaptive, scalable models for real-time control systems using sensor networks with different physical properties under time-discontinuous conditions. Theme II - Metrology Data analytics will create a smart knowledge system to unify metrology language, understanding, and usage between design, production and verification for geometrical products manufacturing; Establishment of data analytics systems to extract maximal information from measurement data going beyond state-of-the-art for optimisation of the manufacturing process to include system validation and product monitoring. Platform research activities will underpin the Hub's vision and core research programmes, stimulate new areas of research and support the progression of fundamental and early-stage research towards deployment and impact activities over the Hub's lifetime. In the early stage of the Hub, the core research programme will focus on four categories (Next generation of surface metrology; Metrology technologies and applications; In-process metrology and Machine-tool and large volume metrology) to meet UK industry's strategic agenda and facilitate their new products. The resulting pervasive embedding and integration of manufacturing metrology by the Hub will have far reaching implications for UK manufacturing as maximum improvements in product quality, minimization of waste/rework, and minimum lead-times will ultimately deliver direct productivity benefits and improved competitiveness. These benefits will be achieved by significantly reducing (by 50% to 75%) verification cost across a wide swathe of manufacture sectors (e.g. aerospace, automotive, electronics, energy, medical devices, optics, precision engineering) where the current cost of verification is high (up to 20% of total costs) and where product quality and performance is critical.

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  • Funder: UK Research and Innovation Project Code: EP/M027015/1
    Funder Contribution: 1,422,790 GBP

    Since the 2011 Fukushima disaster, a major priority for the nuclear sector has been to develop accident tolerant fuels (ATFs). A very promising ATF is uranium-nitride (UN). UN has a high thermal conductivity, enabling heat to be transferred efficiently so the fuel is meltdown-resistant. UN has a high fissile content, so more power can be generated than with existing oxide fuels for the same enrichment level. Mixed UN/PuN is a fuel option for Generation IV reactors breeding fissile material and producing less long-lived radioactive waste. So, UN is a safer, more environmentally friendly, and sustainable nuclear fuel. For similar reasons uranium-carbides are also attractive ATFs. However, preparing uranium-nitrides and -carbides by traditional routes presents challenges. An attractive approach is to use molecular uranium-nitride and -carbyne precursors and decompose them to binary nitrides and carbides. Sadly, for decades there were few molecular uranium-nitrides so a molecules-to-materials approach was not realistic. The situation for uranium-carbynes is worse; there are only two spectroscopic reports of uranium-carbynes at ~10 Kelvin. Recently, we prepared the first molecular uranium-nitride triple bonds (Science, 2012, 337, 717; Nature Chemistry, 2013, 5, 482). Metal-ligand multiple-bonding is fundamentally important in chemistry and we have made a number of contributions in this area (e.g. J. Am. Chem. Soc. 2014, 136, 5619; Angew. Chem. Int .Ed. 2014, 53, 4484) and preliminary results show that our molecular nitrides can be controllably decomposed to binary nitrides which opens up a molecules-to-materials approach. This Proposal aims to apply our recent coordination chemistry to the preparation of materials for energy in Grand Challenge and Priority Areas. We will develop a new range of uranium precursors to generate a platform to expand the range of nitrides. This exploits a blend of steric and electronic properties uniquely suited to stabilising uranium-ligand multiple bonds. Using these precursors we have identified four routes to maximise our chance of success to prepare high-value uranium-carbynes which have no precedent. With an expanded range of molecular uranium-nitrides and new uranium-carbynes we will build on preliminary results and investigate their decomposition to binary materials. The availability of new precursors leads to the possibility of exploring high pressure phase transitions to give new polymorphs. This is directly relevant to understanding fuels under extreme conditions in nuclear reactors and these metallic polymorphs are interesting to study as their itinerant vs localised 5f electron behaviour is magnetically fascinating and crucial to designing better ATFs. We will combine synthetic, structural, and materials studies with interdisciplinary magnetometric, computational, and spectroscopic studies with collaborators to give a comprehensive understanding of uranium-nitrogen and -carbon bonding, reactivity, and materials applications. A Fellowship will provide the best opportunity to oversee this complex programme of research, manage an intensive array of collaborations, and make the time to engage with the nuclear industry and translate academic advances on to the next level into industrially relevant applications. The researchers on this project will develop a range of skills in a recognised strategic skills shortage area. Our molecules provide unique opportunities to probe the nature and extent of covalency in uranium bonding; this issue is long-running, still hotly debated, and important because of the nuclear waste legacy in the UK. Spent nuclear fuel is ~96% uranium and the official Nuclear Decommissioning Authority figure for nuclear waste clean-up bill is 70 billion pounds. If we can better understand the chemistry of uranium this may in the future contribute to ameliorating the UK's nuclear waste legacy and provide new routes to ATFs to be developed with the Nuclear Industry.

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  • Funder: UK Research and Innovation Project Code: EP/M005127/1
    Funder Contribution: 100,174 GBP

    In state-of-the-art laboratories worldwide, gases of atoms are being cooled down to temperatures less than a millionth of a degree above absolute zero. At this extreme coldness, quantum mechanics takes over; the atoms lose their individual identities and become smeared out into a giant wave of matter. This quantum gas hosts a range of bizarre behaviours, from its capacity to undergo wave-like interference to its embodiment of a superfluid, a fluid with no resistance to motion. The quantum gas is far from just a scientific curiosity. It represents a clean and pure exemplar of a many-particle quantum system, giving rich insight into the quantum world. Atomic physics techniques empower experimentalists to precisely tune its physical properties and manipulate it in time and space. Due to these facets, quantum gases are being exploited as "emulators" to recreate and understand complicated physical phenomena, from superconductors and turbulence to black holes and the Big Bang. The quantum gas also holds exciting technological prospects. Their exceptional sensitivity to being disturbed is driving their development as ultra-precise sensors, e.g. of gravity, for which they are touted to lead to major advancement in oil and mineral exploration. Meanwhile, their unprecedented quantum control makes these gases candidates for performing quantum gate operations, the basis of the much-lauded quantum computer. Recent experiments in quantum gases have created a "quantum ferrofluid". Being both a superfluid and a ferrofluid, this novel state lies at the interface of two of our most bizarre fluids. Ferrofluids are liquids dispersed with tiny magnetic iron particles. Just like bar magnets, the particles interact over long-range, prefer to lie with north and south poles being adjacent, and become aligned in an imposed magnetic field. This leads to peculiar patterns and instabilities in the fluid, but, more importantly, enables the flow and physical properties to be controlled via magnetic fields, as exploited in ferrofluid technologies in medicine, information display and sealants. The quantum sibling of the ferrofluid, the quantum ferrofluid, has been formed from an ultracold quantum gas of magnetic atoms. This gas is being hotly researched to probe its novel properties and potential exploitation. Its magnetic nature extends the above-mentioned capabilities of the quantum gas into new territories, e.g., providing a testbed of quantum magnetism, emulation of systems with long-range interactions, and a sensitivity to magnetic fields which can be exploited in a new generation of magnetic sensors, with potential applications from geological exploration to military detection. Meanwhile, the long-range magnetic interaction between atoms is particularly attractive for quantum computation since it allows the computational operations to be performed at a distance. The fundamental nature of superfluidity in the quantum ferrofluid remains uncharted, and uncovering it is the core aim of this project. With superfluidity underpinning the transport properties of the system, we will reveal how the quantum ferrofluid moves and flows, swirls and gyrates, and responds to agitation. This is of fundamental interest to our understanding of superfluidity in general, but, more specifically, is of great practical benefit for future manipulation and exploitation of the quantum ferrofluid. The distinctive behaviour of conventional ferrofluids and their virtuous control via magnetic fields is suggestive of a rich plethora of novel superfluid behaviour and a new dimension of control over the superfluid state. The quantum ferrofluid may in turn provide insight into the conventional ferrofluid; being superfluid, with an absence of viscosity, the quantum ferrofluid embodies a simplified version of the ferrofluid from which outstanding problems in ferrofluids can be tackled afresh.

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