cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1910022
title: INS studies of Nafion and model compounds

description: In the archetypal hydrogenoxygen proton exchange membrane fuel cell design, a proton-conducting polymer membrane (typically Nafion) contains the electrolyte solution that separates the anode and cathode sides.  How water is distributed in the Nafion membrane is a continuing subject of investigation by a range of computational, spectroscopic and imaging techniques. INS spectroscopy  will largely only see the modes associated with the acidic proton in the dry ionomer and the water and/or hydroxonium ions in the wet material. The aim of this proposal is to characterise the modes associated with the acid proton in Nafion and how the water is present in the polymer as a function of concentration. We also wish to measure trifluoromethanesulfonic acid and perfluoro(3-oxapentane-1-sulfonic acid, which are model compounds of the sulfonic acid functionality and the pendant side chain.
DOI: 10.5286/isis.e.rb1910170
title: INS studies of carbon fibre polyimide composites

description: Advanced composites are engineering material that offer similar mechanical properties to metal alloys but are much lighter. The materials consist of fibres embedded in a polymer matrix and there is a need for a spectroscopic technique that can examine the cured resins in the presence of the fibres to aid the understanding of the cure chemistry. Inelastic neutron scattering (INS) has considerable potential in this regard since two common fibre types: glass and carbon are, almost, invisible to neutrons.
DOI: 10.5286/isis.e.rb1910411
title: Characterisation of residual stresses and d0 variations in additively manufactured Laser Beam Melted (LBM) AISI 316L

description: Additive manufacturing, otherwise know as 3D printing is gaining in industrial relevance as a manufacturing technique partially due to the ability to fabricate complex geometries.  Laser Beam Melting is one of the techniques used for additve manufacture of metallic components.  The laser locally melts a bed of powder material generating high temperature gradients which can generate high residual or "locked-in" stresses.  The understanding of These residual stresses are important for the safe application of components manufactured by these methods.  This proposal aims to improve the state of the art of the measurement of the residual stresses in these types of structures by conducting a fundemental study without prior assumptions using the unique capabilities of the ENGIN-X instrument
DOI: 10.5286/isis.e.rb1910483
title: Powder neutron diffraction studies of the complex BiFeO3-NaNbO3 phase diagram

description: Multiferroic materials which exhibit 2 or more of the ferroic order parameters continue to attract extensive attention. The most widely studied multiferroic is bismuth ferrite (BFO) owing to room temperature magnetic and electric ordering. However, high leakage currents and capacitances and a complex magnetic structure act as barriers to commercialisation. One way two overcome these problems is to dope either the A and/or B-site in these materials. We have recently been investigating the solid solution between BFO and sodium niobate; an importan ferroelectric. We observe a complex series of phase transitions with increasing sodium content. However, the similarity of these phases and the insensitivities of x-rays to oxygen (important in determining octahedral tilt) limits our understanding. We propose to collect complementary neutron data to further unravel this phase diagram.
DOI: 10.5286/isis.e.rb1910486
title: Quantum Spin Ice ground states and Structural Disorder in non-Kramers rare-earth pyrochlores

description: Pyrochlore oxides based on non-Kramers rare-earth ions, such as Pr3+ and Tb3+, are candidate materials for the formation of the Quantum Spin Ice. However, structural disorder is thought to be determinant in the selection of this exotic magnetic ground state. Slight level of disorder can indeed induce transverse fields on the Ising spin variable and turn a classical spin ice into a quantum spin ice. When disorder and thus transverse fields are stronger, the Ising spin variables become essentially electric quadupolar degrees of freedom, and the system remains paramagnetic. It is thus of paramount importance to establish detailed knowledge on the type and density of disorder in such materials. We want to finely characterise disorder in our existing samples of Pr2Zr2O7, Pr2ZHf2O7 and Tb2Hf2O7, for all of which showing signatures of quantum spin physics in low-energy neutron spectroscopy.
DOI: 10.5286/isis.e.rb1910565
title: Vibrational Spectroscopy of Imidazole Based Hydrogen and Halogen Bonded Organic Ferroelectrics

description: Organic ferroelectrics are in the focus of current research because of their potential applications as a material to address global challenges. These lightweight, flexible and nontoxic materials have potential applications in energy storage, medical ultrasound imaging and in data storage in computers. The dynamics of protons are considered as the key mechanisms of the functionality of these materials. To build on our previous investigations on hydrogen bonded organic ferroelectrics, in this proposal I propose to investigate simultaneous Raman and INS spectroscopy of a number of imidazole based organic ferroelectrics to understand their finger print motion and to correlate that with their ferroelectricity. These experiments are complemented with QENS experiments and DFT based lattice dynamics simulations.
DOI: 10.5286/isis.e.rb1910637
title: Compressible Liquids

description: Liquids are commonly known to be incompressible. However, a recently invented class of materials called Porous Liquids, which exhibit permanent porosity in the liquid phase, may be compressible. These porous liquids, when under pressure (0.2-100 MPa), may potentially reduce in volume as the bulk liquid will forcibly occupy the cavities thereby reducing the total volume of the liquid. As the synthesised porous liquids can have up to ten percent free space, there is the potential for these porous liquids to undergo much greater reduction in volume than for conventional liquids when pressure is applied. If successful, these experiments will prove the existence of the first compressible liquid.
DOI: 10.5286/isis.e.rb1510087
title: Co-adsorption of eggshell membrane polypeptide-surfactant mixtures at oil-in-water emulsion  SANS study

description: An eggshell membrane polypeptide is highly surface active and effective at emulsion stabilization. We explore how to use SANS to study the interfacial layers surrounding the emulsion drops at the oil/water interface under a range of premixed peptide and SDS concentration. This is then followed by adsorbing peptide onto SDS stabilized emulsion drops. The same expt will then be done in the reverse order to check how SDS can replace the peptide in the peptide stabilized emulsion. We expect the ranges of replacing concentrations are different and these differences may well explain the different emulsion stability as often observed in product formulations. SANS is unique in unraveling such fantastic information about molecular adsorption and replacement at the oil-water interface. As the signals are mostly weak, we request 4 days on SANS2d.
DOI: 10.5286/isis.e.rb1610252
title: High precision measurements of the spin wave dispersion in Yttrium Iron Garnet

description: Yttrium Iron Garnet (YIG) is a material with extremely wide ranging applications, having  the narrowest ferromagnetic resonance linewidth of any known material. Despite decades of experiments on this material, data relating to its full magnon spectrum is sparse. The spectrum is known to contain 20 branches, but the most thorough work to date relies upon a 3-parameter hamiltonian derived from fitting just 3 (the only 3 that were observed in what is still the only neutron spectroscopic measurement on this material). Increasing interest in YIG for applications in magnonics (the magnon equivalent of electronics) necessitates a direct measurement of the optical magnon modes. Following RB1520403 we have sourced larger, purer crystals and we propose to continue the work we have started and produce the definitive data set on this material along with the most thorough analysis possible.
DOI: 10.5286/isis.e.rb1610316
title: Spectral signatures of the magnetically hidden octupolar order in Sr2VO4

description: We propose to study low-energy magnetic excitations associated with the low-temperature ordered phase in polycrystalline Sr2VO4. This layered perovskite compound exhibits an enigmatic two-step phase transition between 122 K (onset) and 97 K (offset), observed in the electronic specific heat, in optical conductivity, and as a clear jump both in the lattice constants and in the magnetic dc susceptibility. However, according to a more recent theory, the low-temperature phase represents an exotic (?pi,pi?) ordering of magnetic octupoles that exhibits no magnetic Bragg peaks, but possesses two characteristic modes of low-energy magnetic excitations that could show up in the inelastic neutron scattering spectra. Here we suggest to look for signatures of these modes.
DOI: 10.5286/isis.e.rb1710493
title: The Power of Neutron Reflectivity for Batteries

description: Catastrophic failures of lithium batteries is a major safety concern, however our understanding and control over the mechanisms of these failures is still lacking. Lithium is unlikely to be usurped as the best candidate for high performance batteries, so further understanding to prevent future debacles like the note 7 are of utmost importance. Neutrons are ideally suited to studying lithium batteries since they can be used with complex sample environment and are highly sensitive to lithium (which unusually has a negative scattering length). We aim to start with simple proof of principle reflectivity measurements on different substrates (electrodes) to help optimise the sample environment and find what is possible with these systems with reflectivity. We aim to look at kinetic lithium loading and unloading in silicon, graphite and glassy carbon.
DOI: 10.5286/isis.e.rb1720135
title: Ionic mobility in soggy sand electrolytes

description: Ionic liquids (ILs) are gaining increased interest as electrolytes given their thermal and chemical stability, wide electrochemical windows, and ionic conductivities. However, leakage still remains an issue with respect to their use in all solid devices given their liquid nature at room temperature. Thus, research efforts are concentrated on obtaining a solid-like electrolyte with properties as close as possible to those of pristine ILs. Among other alternatives, IL-based chemical gels (ionogels) offer great promise because they are capable to confine larger amounts of ILs within its structure. This sort of electrolytes fall into the category of the recently discovered "soggy sand" electrolytes where ion absorption on the insulating polymer network promotes a preferential ion diffusion and an enhanced conductivity for a certain IL content. Herein, we wish to study this system by QENS.
DOI: 10.5286/isis.e.rb1720151
title: Probing the magnetic structure of transition metal pyrovanadates Co2V2O7

description: We had been given 1 day of beam time on WISH, RB1710144, to investigate the magnetic structure of T2V2O7 (T=Mn, Ni, Co)  We performed power neutron diffraction measurements on Mn2V2O7 and Ni2V2O7 on WISH in given 1 day of beam time and obtained very interesting results. However, due to short time on WISH we could not measure Co2V2O7. As Co2V2O7 exhibits very interesting magnetic properties below 8K, possibility of canted antiferromagnetic ordering, we therefore propose to carry out powder neutron diffraction on Co2V2O7 sample to determine the magnetic structure as well as any structural anomalies occurring at TC. The experiment is required to be performed between 2 K and100 K (above Tc to investigate temperature dependence of diffuse scattering) on the time of flight WISH diffractometer. We therefore require one day of beam time on WISH to investigate magnetic structure of Co2V2O7.
DOI: 10.5286/isis.e.rb1720222
title: Adsorption of bioengineered antibodies at the oil/water interface

description: Following our previous study of interfacial adsorption of the basic version mAb COE-3,  we wish to continue this work by exploring how two modified mAbs adsorb at the same oil/water interface by neutron reflection. Inter is preferred because we have built technical capability on this instrument. COE-7 and COE-8 have enlarged Fab and Fc domains and reduced globular stability. Our specific aims are to (a) determine the actual thickness and volume fraction of them and (b) examine the effect of pH on their interfacial distribution. The results will enable us to compare their extent of distributions into the oil region with other globular proteins at the interface. We can then answer if all the globular proteins unfold and produce characteristic segment distributions into the oil region.
DOI: 10.5286/isis.e.rb1720295
title: SANS Study of the interaction of reconstituted model wheat waxes with non-ionic surfactants

description: The understanding of the plant wax-surfactant interaction process is crucial to the development of more effective pesticide and fungicide formulations, essential for improving food production whilst reducing environmental impact. It is widely recognised that the detergency actions of surfactants can hugely influence the transport properties of both water and active ingredients through the waxy leaf surface, however the role of the different wax components is not well understood.The aim of this work is to study how long-chain alcohols and alkyl-esters (the main components that make up wheat and barley waxes) interact with non-ionic CnEm micelles. This study will enable us to determine how representative the alcohol and ester chains are in the reconstituted waxes and to observe the influence of these component chains upon the miceller shape and structure through solubilisation..
DOI: 10.5286/isis.e.rb1720327
title: Investigation of the hydrogen bonding and anisotropic displacement parameters in the negative area expansion material 4-chloroimidazole

description: We will investigate the structure of 4-chloroimidazole, which undergoes extreme anisotropic thermal expansion. This is believed from our initial x-ray results to be due to a particular combination of weak C-H---Cl and strong N-H---N hydrogen bonds. Both the interatomic contacts and ADPs obtained from the SXD experiment will be used to provide a detailed description of the mechanism responsible for this behaviour. The ADPs will be used in a rigid body analysis to distinguish between the high-frequency internal modes from low-frequency external modes. and will be complemented by an off-line Raman study. In addition to the fundamental interest in further our understanding of extreme anisotropic expansion the knowledge obtained will be of use in designing functional materials, since one may tune the response of a thermally-driven actuator or switch.
DOI: 10.5286/isis.e.rb1720357
title: Pressure-induced proton migration in an energetic co-crystal

description: The results of these studies will provide valuable information on the effects of extreme conditions on the structures of an energetic salt and co-crystal formed between nitrotriazolone and biyridine, and in particular whether pressure-induced proton transfer is responsible for the observed colour change. This insight into the structural data obtained will strengthen our knowledge of the relationship between molecular packing and sensitivity to impact and shock. The high-quality structural data that will be obtained, including the effects of pressure on hydrogen-bonding motifs, will provide insight into molecular energy transfer, detonation mechanisms and, particularly in this case, the sensitivities to initiation. The results will also be of significant interest to theoreticians who seek to develop predictive models of the behaviour of energetic materials under operational conditions.
DOI: 10.5286/isis.e.rb1720454
title: Local magnetic structures of YBCO high-Tc superconductors from neutron total scattering

description: Understanding high-temperature superconductivity is a major aim of condensed-matter science, which is of fundamental importance and may ultimately allow the design of materials with higher superconducting temperatures. In the superconducting state and its precursor "pseudo-gap" state, magnetic moments (spins) do not form a conventionally-ordered structure. However, they are locally strongly correlated, and these local correlations may be important for superconductivity. We propose to use a combination of neutron total-scattering experiments and atomistic refinement techniques to map the nano-scale spin arrangements in the canonical high-temperature superconductor YBa2Cu3O{6+x} (YBCO). The main aims of proposal are to determine the length-scale of spin correlations, the magnitude and nature of their anisotropy, and whether they show a liquid-crystal-like (nematic) ordering.
DOI: 10.5286/isis.e.rb1810129
title: The role of zero-point fluctuations in a quantum-disordered spin-dimer compound

description: Recently a great deal of theoretical and experimental interest has been directed at a class of magnetic materials which undergo phase transitions at zero temperature. These quantum phase transitions are driven by quantum (or zero-point) fluctuations, which are reflected in exotic magnetic behaviour near the boundaries between phases. We have recently reported a study on a compound Cu(pyz)(gly)(ClO4), which comprises a network of spin-dimers and exhibits two phase transitions as a function of magnetic field. The experimental accessibility of both of these magnetic field driven transitions permits a unique opportunity to study the magnetic excitations in each of the low temperature phases. We shall therefore directly investigate the role of the quantum fluctuations in the vicinity of the crossovers, where they are predicted to influence the nature of the excitations.
DOI: 10.5286/isis.e.rb1810447
title: Lipid exchange dynamics between native lipoprotein particles and human cell mimics   Increasing the complexity of the cell membrane

description: Atherosclerosis is the primary cause of death in westernized societies. Clinical indicators include not only the net lipoprotein concentration but also the ratio between the various lipoprotein particles such as low density lipoproteins (LDL) and high density lipoproteins (HDL). Many different factors are thought to affect their structure and the way they interact with the various vessel wall components. Understanding the initial events leading to atherosclerosis is the main focus of our group. Using neutron scattering techniques we are currently unraveling the lipoprotein ability to unload their lipid cargo and how this relates to their structure/composition relationship by monitoring the changes that occur upon native lipoprotein interactions with mimics of the blood vessel wall.
DOI: 10.5286/isis.e.rb1810506
title: Satisfying the need for contrast in antimicrobial research

description: Gram-negative bacteria, which cause a variety of diseases including meningitis, plague, sepsis and food poisoning, are becoming increasingly antibiotic resistant. One reason is their robust outer membrane (OM) which can resist antibiotic penetration. We have been combining our recently developed OM model with neutron science to measure the penetration of an important antibiotic, polymyxin (PMB), into the OM. These have shown the importance of the critical melting of the OM at body temperature in allowing PMB to work. These have been supported by in vivo data on live bacteria. We need to measure where the antibiotic resides in the OM model and this proposal seeks to set up a fully deuterated OM model using d-LPS produced in our own laboratory. This will help with our short term objectives with PMB but also provide a new sample environment for future antibiotic penetration studies.
DOI: 10.5286/isis.e.rb1810750
title: Probing Li+ diffusion mechanics in NMC bulk and nanomaterials with varying nickel concentration

description: Recent advances in energy materials have led to the development of high capacity insertion cathodes for Li-ion batteries. One of the most promising of these materials is lithium nickel manganese cobalt oxide (NMC). For all insertion electrodes, lithium diffusion ultimately governs all electrochemical activity. Generally, the easier lithium can diffuse through the structures, the greater the electrochemical properties. However, lithium diffusion has yet to be experimentally characterised on a local scale for NMC, a highly attractive material for commercial application. Thus, this study proposes investigation into the lithium diffusion properties in NMC, the effect of particle size and the effect of nickel concentration (which has previously been shown to increase diffusive properties) in one complete study.
DOI: 10.5286/isis.e.rb1820207
title: Deformation behaviour of gamma double prime strengthened nickel-based superalloys studied by in-situ neutron diffraction

description: Inconel 718 alloys are widely used in industry. However, deformation behaviour of the different phases in the alloys during plastic deformation under loading has not been measured in-situ using neutron beams.  In this experiment, we will study the deformation behaviour of strengthening phase and matrix in the Ni-based superalloys by doing in-situ neutron diffraction during loading. The outcome of this experiments will reveal elastic properties of strengthening phase, stress during deformation, which will be useful to provide enhanced understanding of the widely used materials and for industry to optimise the process to obtain optimum properties.
DOI: 10.5286/isis.e.rb1820214
title: Spin dynamics in the iron-based superconductor CsCa2Fe4As4F2

description: The relationship between spin fluctuations and superconductivity is of paramount importance in understanding the iron-based superconductors. We have recently investigated the superconducting properties of the newly discovered bilayer CsCa2Fe4As4F2 compound with Tc=28.3 K using muon-spin rotation measurements. Our results [Phys. Rev. B 97, 060506(R), (2018)] show two gaps (s+d-wave) with at least one nodal gap. We propose to search for a magnetic resonance in this new material by using inelastic neutron scattering with the high flux time-of-flight spectrometer MERLIN.
DOI: 10.5286/isis.e.rb1820265
title: Surfactant induced gelation of TEMPO-oxidized cellulose; Using betaine-based wormlike micelles to modulate rheological behaviour

description: Our group has been working cellulose nanofibrils (OCNF) which form hydrogels in the presence of certain additives. Previously, we have studied the effect of salt, single surfactants and alcohols on cellulose nanofibrils gelation as additives. None of these additives form viscoelastic fluids alone. In order to further extend our control of the rheological behaviour of OCNF hydrogels, we have now begun to explore a mixture of surfactants capable of forming wormlike micelles (WLM). WLM form entangled networks, with properties similar to polymer solutions. We combine these two physical networks in a single system. Here, we would like to use contrast variation studies to evaluate the cross-interactions between these two different networks in order to establish if the rheological behaviour observed is due to synergistic interactions between OCNF and WLM.