Electro-chemical devices (fuel cells, electrolysers etc) are at the forefront of the drive to a 'net-zero world' with hydrogen as an important energy storage medium and fuel for the application of sustainably derived electricity. Even with the projected development of the energy system towards a largely fossil-fuel free system, CO2 separation will continue to be required for chemical processes. The work proposed builds on the collaboration between the Universities on Manchester, Newcastle and UCL which has flourished over the past five years, to develop more efficient and robust technologies to achieve a carbon negative industrial landscape. The ability to operate fuel cells at higher temperatures without humidification means that the amount of equipment needed and hence cost is reduced. It also means that potentially cheaper catalysts can be used, and the purity of the fuel does not need to be rigorously controlled, all of which leads to cheaper and more efficient systems. The overlap between fuel cells and electrolysers is very significant as an electrolyser is simply a fuel cell in reverse; as such similar problems are manifest. In addition, an exciting electrochemical process for gas separation (CO2 removal) is under development, again with significant overlap in terms of developmental challenges. This proposal builds a team of researchers with complimentary skills to tackle the challenges highlighted. The synergies between the very high-level characterisation expertise to examine the processes taking place in the systems, coupled with the electro-chemical developments which are on-going, mean that development and optimisation can take place quickly with understanding being shared to tackle the overlapping nature of the obstacles to implementation of these vital technologies.

The proposal builds on an existing collaboration which has focussed on achieving a multi-scale understanding of the material-structure response to thermoacoustic excitation at up to 750K and 800 Hz using detailed experiments and simulations, in plates and beams of conventionally-manufactured metals, ranging from aluminium to Hastelloy X. Results have shown, at a microscale, a tendency for deformation to concentrate in the larger grains of oligocrystal within the material microstructure at locations disparate from where macroscale homogeneous analysis predicts (Carroll et al., Int. J. Fatigue, 57: 140-150, 2013), demonstrating that non-uniformity in the microstructure can lead to significant and service critical errors in predicting failure. Further laboratory-scale experiments, using maps of surface deformation measured during broadband thermoacoustic excitation, have confirmed the presence of mode jumping and shifting when non-uniform heating generates thermal buckling (Lopez-Alba et al, J. Sound & Vibration 439:241-250, 2019). With this in mind, the research team scaled these tests to component scale, establishing quantitative validation procedures for coupled models of thermoacoustic excitation of simple components (Berke et al, Exptl. Mech., 56(2):231-243, 2016). In doing so, the team developed two unique pieces of experimental apparatus: in Illinois, for localised heating and modal excitation of coupons; and in Liverpool, to deliver spatially distributed heating at 21kW while simultaneously applying random broadband excitation to small components. Both rigs have real-time, full-field temperature and displacement measurement capability. Lambros and Patterson have correspondingly complementary expertise in multi-scale mechanics of materials under extreme loading (Lambros) and in measurement, simulation and validation of structural responses (Patterson). It is proposed to exploit these findings, facilities and expertise to understand the potential for additive manufacturing in the production of components subject to extreme thermomechanical excitation in demanding environments. It is likely that this type of structure will be produced in small quantities rendering it appropriate to consider additive manufacturing; however, the extreme conditions of temperature and mechanical loading make it a challenging application for any material. Successful design, manufacture and service deployment of such components requires an understanding of the multi-scale material-structure response to loading and its evolution with a component's progression from its virgin state through shake-down towards initiation of detectable non-critical damage. These responses are understood at a fundamental level for subtractively-manufactured metals; however, there is very limited fundamental understanding of these material-structural interactions for additively-manufactured metals, at either room temperature (Attar et al, IJ Mach. Tools & Manu., 133: 85-102, 2018, Foehring et al, Mat. Sci. Eng. A, 724: 536-546, 2018) or elevated temperatures (Roberts et al, Progress. Add. Manu., 1-8, 2018). It is hypothesized, because of the unique microstructure containing the previously studied larger grains of oligocrystal, the complex thermomechanical history of their manufacture and the presence of significant residual stresses, that the response of additively-manufactured metals under extreme thermoacoustic loading will be significantly different from their subtractively-manufactured counterparts, especially in defect-driven processes such as failure. This proposal extends the research of Lambros and Patterson by adding the additive manufacturing expertise and facilities provided by Sutcliffe (R&D Director at Renishaw AMPD, RAe Silver Medallist 2018 with over 20 years researching metal additive manufacturing) who has unparalleled access to the latest additive manufacturing technology.

One hundred and fifty ago, life expectancy in the UK was about 43 years. Improvements in nutrition, medicine and public health have dramatically increased this such that those born today can expect to live for over 80 years. This 150 year period is but the blink of an eye in evolution terms, and the evolution of our musculoskeletal system has not caught up with the increased life expectancy. It is therefore no surprise that musculoskeletal disorders are one of the biggest expenditures in the annual NHS budget (about £5.4bn). Our vision is for lifelong musculoskeletal health. We consider the only way to achieve this is to identify musculoskeletal problems early in life, then make small interventions to correct them before they become chronic. This preventative approach needs new technology which we will create using the equipment in the Medical Device Prototype & Manufacture Unit. We seek to manufacture early intervention implants using material that is tailored to make the surrounding bone stronger by controlling the bone strain experienced. We want to make smart instruments and implants that can measure biomarkers in synovial fluid to provide objective measures of joint health. We want to deploy new biomaterials like nanoneedles that can bypass the membrane of bacteria cells and provide anti-infection coatings on our implantable devices. We will manufacture ligament, tendon and capsule repair patches using a soft tissue 'velcro' fixation combined with functionalised surfaces that adhere to soft tissues on one side, yet provide a low friction sliding surface on the other side. We also want to better understand the ageing process of osteoporosis and the effects of bisphosphonate theory. Finally we want to perform higher fidelity laboratory testing of musculoskeletal tissues, both to understand better the pathology, but also the response of tissue to our proposed treatments. The proposed Medical Device Prototype & Manufacture Unit would enable breakthroughs in all these interrelated research themes. The powder bed fusion additive manufacture (AM) machine and 2-photon lithography AM machine allow manufacturing of porous lattice materials at the range of scales we need to create stiffness matched implants with 150 micron features down to microfluidic channels for our sensing technology and nanoneedles with sub-micron features. The nano CT scanner has a higher resolution (sub-micron) than currently available and the 3D microscope is equipped with confocal profiler with 100 nanometre resolution - these imaging instruments will allow unprecedented surface and internal imaging of pathological tissues and the response of tissues to our interventions. Our research will be conducted in an environment that will strongly encourage translation. The Prototype & Manufacture Unit will be set up with all the regulatory approval and quality control to enable us to manufacture devices from first off prototypes through to small batch production parts for early clinical safety studies. This combination of cutting edge AM and imaging equipment in an environment with strong emphasis on translation would enable us to break new ground in all our research themes and also bridge the gap between exciting laboratory testing and clinical practice.

Lasers are rapidly becoming more useful - they are widely available at shorter wavelengths, emitting shorter pulses and at higher energies and powers than ever before. These characteristics make them especially useful for several industrial applications such as velocimetry, micro-machining and welding, where the beam characteristics delivered to the workpiece are critical in determining the success and efficiency of the process. Unfortunately, the very characteristics that make these laser pulses so useful - their short pulse lengths, low wavelengths and higher energy and power - make them absolutely impossible to deliver using conventional fibre optics. This means that those wishing to exploit the new laser systems would currently have to do so using bulk optics - typically, several mirrors mounted on articulated arms to deliver the pulses to the workpiece.We propose to use an alternative optical fibre technology to solve this problem. Hollow-core fibres which guide light using a photonic bandgap cladding have roughly 1000 times less nonlinear response than conventional fibres, and have far higher damage thresholds as well. In previous work, we concentrated on longer nanosecond pulsed lasers, and demonstrated that we could use these fibres to deliver light capable of machining metals. However, it is with the picoscond and sub-picosecond pulse laser systems now becoming more widespread that the hollow-core fibres really come into their own. For these shorter pulses, transmission through conventional fibres is limited not only by damage, but first by pulse dispersion and optical nonlinear response. These problems can only be surmounted using hollow-core fibre - no competing technology has come even close.Our work programme has several strands, with the common objective being to devise systems capable of delivering picosecond-scale pulses through lengths of a few metres of fibre, at useful energies and powers. To do this, we need to be able to efficiently couple light into the fibres and transmit them, single-mode, over a few metres of fibre with low attenuation. We plan to focus our attention on doing this in the wavelength bands around 1060nm and 530mn, and to investigate the possibility of extending the work to shorter wavelengths. We will work closely with several collaborators from the industrial/commercial sector, ranging from a UK-based supplier of relevant laser systems through to a company developing machining systems and indiustries which actually use such systems. In this way, we plan to provide UK-based industry with a competitive edge on teh global stage, by providing them with access to an academic area where the UK is an acknowledged world leader.

Micro-robots have great potential for evaluation and treatment of medical conditions. Such devices require highly controlled actuation at a micro-scale to provide controlled motion, testing of tissue compliance, biopsy, etc, and this is a prospect offered by functionally-graded shape memory alloys (SMAs). An SMA has the ability to "remember" its original shape and that when deformed returns to its pre-deformed shape when heated. Such alloys have sparked great interest ever since their first development. Functional grading of SMAs (i.e. locally modifying the properties of the material to tailor the SMA effect in different parts of the device) allow the design of more complex and hence much more controllable actuation mechanisms. Devices and components manufactured from functionally graded SMAs can provide actuation in response to external stimulation (stress or temperature variation, e.g. via induction heating), outperforming conventional actuation mechanisms such as electromagnets or electrical motors in terms of work output density. Such performance is ideal for micro-devices for minimally invasive medical applications such as precise incision, tissue identification, tactile sensing for disease and tweezing, as well as more ambitious shape transformations for "unpacking" structures in situ and "intelligent" stents and patches. The manufacturing challenge here is to achieve that functional grading at a micro-scale, by a combination of locally tailoring the material composition and thermal history. This will be achieved via development of a novel process, functionally graded Laser Induced Forward Transfer (FG-LIFT). This process will use a multi-track 'donor ribbon' (rather like a multicoloured typewriter ribbon) to deposit "sub-voxels" (of typical dimensions a few microns across and hundreds of nm high) of different metals, e.g. Ti, Ni and Cu onto a target substrate, in order to construct voxels each consisting of a number of subvoxel layers of different metals. By altering the laser parameters, subsequent thermal treatment will be used to provide control of interdiffusion within and between voxels providing very tight localised control of composition. 3D microstructures will hence be constructed by continuing to add additional voxels. This FG-LIFT process will be used to manufacture sub-mm and mm-scale SMA components with functional grading at a scale of 10's of microns. This highly challenging concept requires 3D control - at the micro-scale - of both material composition and thermal treatment. By depositing the functionally graded SMA material onto substrates with appropriate material properties (e.g. carbon fibre mats or trace heaters), additional tailoring of the overall performance of the device will be achieved.