To date, most research into the impact of microplastics in the environment has focussed on marine (coastal and ocean) environments. However, there is growing acceptance that microplastics are also pervasive within freshwater (river and lake) systems. The limited number of studies from rivers around the world have all found microplastics to be present within samples of river bed sediments or the water column. This is of concern as the ecotoxicological impact of microplastics will likely have a negative impact on a range of freshwater species with an additional public health concern if pollutants associated with microplastics then enter the human food chain. A fundamental issue regarding the science of microplastics in freshwaters is a lack of data with which to generate physically based models. This thus makes it very hard to establish what are 'normal' levels of microplastics within our rivers and hence whether such levels represent an acceptable level of risk to ecosystems or society more generally, or where clean-up or remediation strategies should be targeted. To make meaningful progress, this issue requires international consensus to be agreed quickly so that ongoing and future research efforts can be properly synthesised to provide meaningful evidence-based policy. The purpose of this proposal is to meet this challenge by assembling a new network of internationally leading freshwater microplastics experts. This network will undertake a focused programme of data collection. By pooling this data and using it to generate new numerical models at a series of workshops the network will be able to reach more robust conclusions as to the overall freshwater plastic flux to the oceans. This will address the significant stumbling block the discipline currently faces and thus allow further development of more physically based models. Such a significant deliverable can only be achieved by the sort of networking opportunity that is facilitated by the global partnerships seedcorn fund.

Periodic water shortages in many regions throughout the world are increasing because of population growth, urbanization, economic development, and climate change. The need to provide a safe drinking water supply from increasingly complex sources polluted by multiple contaminants has motivated the development of novel membrane technologies. Pressure-driven nanofiltration (NF) and reverse osmosis (RO) membrane processes are increasingly used for drinking water treatment because they are capable of removing all pathogens and most organic and inorganic contaminants in a single treatment step. However, more widespread adoption of these technologies has been limited because of inadequate resistance of state-of-the-art NF and RO membranes to (bio)fouling, compaction, and chemical oxidation coupled with a relatively narrow range of solute selectivity. This project will overcome the current NF and RO membrane challenges by using pioneering interfacial polymerization (IP) methods to fabricate active layers of two-dimensional covalent organic frameworks (COFs) interfaced with compatible support media. 2D COFs are crystalline, permanently porous, and layered macromolecules with structure, chemical composition, and porosity set through the rational design of their monomers. COFs will provide separating layers comprising uniform pores with tailored size, shape, and variable chemical functionality in contrast to the amorphous and empirically optimized polyamide active layers present in the state-of-the-art NF/RO membranes. The project contributes fundamental knowledge towards a new class of membranes to affordably solve many of the global water challenges through the design, synthesis, and characterization of a new library of COF-based membrane active layers that will be formed directly on novel support layers and tailored to meet specific performance targets. The novel COF-based membranes have the potential of significantly decreasing the operating costs of membrane based water treatment systems and increasing broader implementation of these technologies.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

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.