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Abstract: The discovery and development of new adhesive materials is critical for real-world applications of polymeric composite materials. Herein, we report the design and synthesis of a library of structurally related phase-separated supramolecular polyurethanes whose mechanical properties and adhesive characteristics can be enhanced through minor structural modifications of the polymer end-group. The interplay between phase separation of the hard domain polar end-groups and soft polybutadiene domains, coupled with tuneable self-assembly afforded by the polar end-groups, gives rise to a class of materials with tuneable mechanical properties. Exceptionally strong supramolecular adhesives and mechanically robust self-healing elastomers were identified. The mechanical properties were investigated through tensile testing. Finally, rheological analysis of the supramolecular materials was used to identify suitable healing and adhesive temperatures in addition to elucidate the supramolecular polyurethanes' thermal-responsive nature.

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Abstract: An integrated carbon capture and utilization (ICCU) process present an ideal solution to address anthropogenic carbon dioxide (CO2) emissions from fossil fuel-driven electricity production, allowing for capturing and subsequent utilization of CO2 instead of current release into the atmosphere. Effective dual-functional materials (DFMs), through the combination of CO2 sorbents and catalysts, can not only capture CO2 but also convert it into higher-value chemicals, such as CH4 or CO, under isothermal conditions within a single reactor are highly desirable for ICCU processes. In this study, we investigate the mechanism of ICCU over 10 %NiCaO by the time-resolved operando XAS/DRIFTS/MS and the influence of a reduction pretreatment on the process and the products formed. During the 1st stage of the ICCU process (carbon capture), CaO adsorbs CO2 resulting in bicarbonate, carbonate, and formate species formation. At the same time, the Ni catalytic active species are oxidized by CO2, leading to the formation of NiO and CO. However, pre-treating the same DFM under hydrogen, during heating to operating temperature, resulted in a switch to CH4 production, suggesting the presence of high levels of surface adsorbed H2. During the 2nd stage of ICCU (CO2 conversion), the NiO generated during capture is reduced by H2 to metallic Ni, which facilitates the reduction of bicarbonates, carbonates, and formats, via H2 dissociation, to produce and liberate gaseous CO. Thus, both adsorption and catalytic sites are regenerated for the subsequent ICCU cycle.

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Abstract: Manufacturing austenitic stainless steels (ASSs) using additive manufacturing is of great interest for cryogenic applications. Here, the mechanical and microstructural responses of a 316L ASS built by laser powder bed fusion were revealed by performing in situ neutron diffraction tensile tests at the low-temperature range (from 373 to 10 K). The stacking fault energy almost linearly decreased from 29.2 ± 3.1 mJm−2 at 373 K to 7.5 ± 1.7 mJm−2 at 10 K, with a slope of 0.06 mJm−2K−1, leading to the transition of the dominant deformation mechanism from strain-induced twinning to martensite formation. As a result, excellent combinations of strength and ductility were achieved at the low-temperature range.

Open Access

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Abstract: Room-temperature macromolecular crystallography allows protein structures to be determined under close-to-physiological conditions, permits dynamic freedom in protein motions and enables time-resolved studies. In the case of metalloenzymes that are highly sensitive to radiation damage, such room-temperature experiments can present challenges, including increased rates of X-ray reduction of metal centres and site-specific radiation-damage artefacts, as well as in devising appropriate sample-delivery and data-collection methods. It can also be problematic to compare structures measured using different crystal sizes and light sources. In this study, structures of a multifunctional globin, dehaloperoxidase B (DHP-B), obtained using several methods of room-temperature crystallographic structure determination are described and compared. Here, data were measured from large single crystals and multiple microcrystals using neutrons, X-ray free-electron laser pulses, monochromatic synchrotron radiation and polychromatic (Laue) radiation light sources. These approaches span a range of 18 orders of magnitude in measurement time per diffraction pattern and four orders of magnitude in crystal volume. The first room-temperature neutron structures of DHP-B are also presented, allowing the explicit identification of the hydrogen positions. The neutron data proved to be complementary to the serial femtosecond crystallography data, with both methods providing structures free of the effects of X-ray radiation damage when compared with standard cryo-crystallography. Comparison of these room-temperature methods demonstrated the large differences in sample requirements, data-collection time and the potential for radiation damage between them. With regard to the structure and function of DHP-B, despite the results being partly limited by differences in the underlying structures, new information was gained on the protonation states of active-site residues which may guide future studies of DHP-B.

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Abstract: This work outlines the development of a workflow that combines both informed and data-driven approaches to process and classify 4D-STEM data utilising signal dimensionality reduction obtained from unsupervised machine learning algorithms. Using these ‘latent space’ representations of the scanned region, we can then apply clustering algorithms to identify regions of similar character. By combining the results of multiple autonomous computations, we would be able to map domains within the crystal and associate a level of confidence to given classifications. This confidence is then used to iteratively improve the learning algorithms and the performance of their dimensionality reduction. Incorporating this as a pre-processing unsupervised workflow would drastically improve the ability to characterise the nano-scale structure of materials, both through production of significantly signal-boosted diffraction data and reduction in laborious manual investigation.