cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1610394
title: Mapping magnetic excitations in insulating phase of NaFe0.52Cu0.48As

description: Magnetism is believed to be linked to superconductivity in cuprates and iron pnictides. However while the parent compounds of cuprates are Mott insulators, the parent compounds of iron pnictides are metallic. We previously found that NaFe0.5Cu0.5As is a Mott insulator with antiferromagnetic order with half-filled Fe orbitals, we propose that this compound is the true parent phase of iron pnictides and magnetism in this compound has more direct bearing on superconductivity than say NaFeAs, in which the stripe magnetic order could a competing phase with superconductivity, similar to stripe order in La2-xBaxCuO4. Here we propose to study the spin waves in NaFe0.52Cu0.48As, since this is as close as we can get to ideal NaFe0.5Cu0.5As.
DOI: 10.5286/isis.e.rb1610431
title: Chain Conformations of Monodisperse PMMA Spinning Solutions

description: In this proposal we seek time to study the chain conformation(that is the way a polymer chain is arranged)  in the solution state on a narrow molecular weight distribution PMMA. This study will allow us to compare the chain conformation in the solution state for a polymer with to those found in nanoscale fibres. Thus we will able to observe any retention of molecular conformation frozen in from the solution state during the rapid fibre forming process in for example electrospun fibres. The studies will provide insight into polymer chain organisation in fibre formation and thus facilitate additional control of fibre properties.
DOI: 10.5286/isis.e.rb1610437
title: SANS experiments on phase separation in Fe-Cr based alloys

description: Low temperature embrittlement of stainless steels is due to phase separation and in this proposal we will further investigate the underlying mechanisms for phase separation. More specifically we our data will provide vital input for improving computer simulations of the phenomenon, which can be used for novel design of alloys and life-assessments of current materials.
DOI: 10.5286/isis.e.rb1620373
title: Mechanical disorder-induced quantum spin liquid in a two-dimensional triangular lattice

description: The quantum spin liquid (QSL) state is one of the possible outcomes of quantum fluctuations advancing magnetic systems into a disordered phase. After more than 30 years of quest for the QSL state, a few examples have been realized. In these systems, the role of quenched disorder turns out to be vital for the survival of an unordered state. We propose muon spin rotation experiments in a new QSL candidate. In this layered organic system, the magnetic layer forms two-dimensional triangular lattice with spin-1/2. The triangular layers are separated by molecular rotors. Their Brownian rotation is prohibited at high temperatures. Below 130 K, however, the motion of the rotor is re-established resulting in electric dipole fluctuations, and destroying the formation of the antiferromagnetically ordered state. Our electron spin resonance study was unable to identify magnetic ordering.
DOI: 10.5286/isis.e.rb1700077
title: The Mechanism of Bam Mediated Outer Membrane Protein Folding

description: The proteins of the outer membrane of Gram-negative bacteria are critical for bacterial survival,from providing basic physiological functions, to impairing virulence and multidrug resistance. The Bam complex has been found to be essential for folding these proteins into the outer membrane.The process by which this is achieved is unknown. The structure of the complex and its individual components are now known. We aim to continue our investigation of the Bam complex by studying BamABCDE in complex with stalled folding intermediates. To do this we will use  specific deuteration and neutron reflectometry in concert with previous polarised neutron reflectometry datasets of the BamABCDE complex bound to a gold surface to probe the structure of the Bam complex as it performs its function.
DOI: 10.5286/isis.e.rb1710047
title: Zwitterionic surfactant self-assembly in deep eutectic solvents

description: Deep Eutectic Solvents (DES) are mixtures of organic salts and hydrogen bond donors, that form strongly hydrogen-bonded room temperature ionic liquids (ILs). DES share many features with ILs (ie. tunable physicochemical properties) which makes them viable green solvents that are less toxic than typical ILs. DES can also be prepared from components which are present in cells, and it has been proposed that they might be one mechanism by which cells can survive in the absence of water, as the DES provides a liquid in which proteins and lipids can retain their function. We are currently investigating the behaviour of amphiphiles with biological interest in DES in order to expand our understanding of the interactions between surfactants with different headgroups and these novel solvents. Here we wish to compare sulfobetaine and phosphocholine headgroup surfactant self assembly in DES.
DOI: 10.5286/isis.e.rb1710116
title: Dynamics in Deep Eutectic Solvents: Effect of Different Anions

description: Deep eutectic solvents (DES) are mixtures of ionic and non-ionic solid compounds with melting temperature much lower than the pure components. Due to the lower toxicity and lower vapour pressure compared to ionic liquids, DESs have found various applications as a solvent medium. Acetamide (CH3CONH2) + LiX (X = Br-, NO3-, ClO4-) forms ionic DES with freezing point close to room temperature. MD simulations on these systems have found that the dynamics of acetamide is strongly anion dependent. It is found that different anions in the lithium salt can significantly alter the hydrogen-bonding network in these DES suggesting existence of a strong structure-dynamics relationship. The proposed experiment will probe the changes in microscopic dynamics and the structure-dynamics relationship in DESs with different lithium salts using QENS technique.
DOI: 10.5286/isis.e.rb1710223
title: Absence of long-range order in K2Ni2(SO4)3

description: In a vast majority of materials that contain a magnetic ion the interaction between magnetic moments residing on magnetic ions causes them to order in a particular fashion. The strength of the interaction typically determines the temperature (Tc, the critical temperature) below which the magnetic subsystem enters the long range ordered state with moments pointing along a given direction. There are rare examples where a particular geometrical arrangement of magnetic moments, for instance on a triangle where each spin pair wants to be in an up-down configuration, prevents the magnetic subsystem to achieve the ordered state and moments are found in a so-called spin-liquid phase, govern by quantum fluctuations. Preliminary results on K2Ni2(SO4)3 suggest that there is no order down to 100 mK. We want to perform the experiments with muons to confirm this hypothesis.
DOI: 10.5286/isis.e.rb1710281
title: Structures and microscopic miscibility for nanoparticles of palladium-ruthenium alloys

description: We are proposing 4 days of beamtime on GEM to conduct the experiment on 10 alloy nanoparticles; PdxRu1-x (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) and PdRuM (M = Rh, Pt, Ir). We have found that these alloys are immiscible in bulk scale but form solid solutions in nanometer scale by using a scanning transmission microscope with an energy-dispersive X-ray analysis. These alloys are expected to be high-performance and low-cost catalysts to remove CO and NOx in exhaust gas of cars. The diffraction patterns and derived pair-distribution functions will provide information on the miscibility in an atomic scale. The large difference between the neutron scattering cross sections of Pd and Ru and the high neutron intensity of GEM are keys in the present experiment. The problems pointed out in the previous rejected proposal have been resolved, i.e., sample mass: 100 mg to 500 mg, PVP: 30% to 10 %.
DOI: 10.5286/isis.e.rb1710393
title: GISANS from photoconductive hydrogel electrodes.

description: The sun is an abundant and cheap source of energy, harnessing it as storable fuel has the potential for a large societal impact. Organic photoelectrodes (PEs) formed from low molecular weight hydrogels are showing promise as PEs for water splitting. Photoelectrochemical data indicates that the gelation method impacts on the photo-response efficiency. This implies the arrangement and size of the fibres formed during gelation is important in their behaviour as PEs. We propose a GISANS experiment using the SANS2d instrument to measure the structure and alignment of the PEs, particularly close to the conductive substrate surface where the alignment is likely to have the most influence. Comparison between preparation methods and of different depths through the hydrated gel film will be vital, hence TOF-GISANS is the most appropriate technique for the measurements to improve gel PE design.
DOI: 10.5286/isis.e.rb1710429
title: Atomic structure of 2NaY-Ga2S3 (Y = Cl, Br, I) liquids

description: Alkali halide sulphide and selenide glasses MY-Ga2X3-GeX2 (M = Li, Na, Rb, Cs; Y = Cl, Br, I; X = S, Se) are promising hosts for active and passive optical devices, solid-state battery applications and chemical sensing.  The glass-forming regions clearly show an important role of alkali halide and gallium sulphide interactions since the maximum glass-forming range was obtained along the composition line leading to a specific composition 2MY-Ga2X3.  Our previous neutron diffraction measurements have shown a mixed gallium and alkali environment in these glasses.  Our goal is to verify whether the mixed environment exist in the glass-forming melt and obtain missing structural information for more simple quasi-binary systems to build-up a realistic structural model for technologically important glasses.
DOI: 10.5286/isis.e.rb1720439
title: Investigating Morphology and Phase Separation in Low-Donor Organic Solar Cells with SANS

description: Organic photovoltaics (OPVs) are a class of solar cells that harvest photogenerated excitations ('excitons') and split them into free charges to generate electrical power. A highly promising but poorly understood OPV architecture is the low-donor bulk heterojunction, in which a small volume of an electron donor is distributed within a host matrix of an electron acceptor, such as C60 fullerene, to facilitate exciton splitting. Based on recent spectroscopic and x-ray scattering results, we propose using small-angle neutron scattering to probe a series of films in which the donor concentration and crystallisability are varied. The observed effects on the spatial distribution of the donor, and its impact on the nanoscale morphology of the host matrix, will help shed light on their underlying operational mechanism, and highlight new routes for higher efficiency OPVs.
DOI: 10.5286/isis.e.rb1800044
title: Neutron flux measurement with neutron activation on Vesuvio

description: The characterization of the neutron flux in a beamline is a crucial information for many experiments. The activation technique allows to measure the neutron flux in a broad energy range from thermal region up to about 100 MeV. This technique is suitable for measuring high instantaneous fluxes, because is based on passive detectors (activation foils). We plan to irradiate 10-20 samples to measure the activation rates of many reactions  that are induced with different probabilities by neutrons with different energies. In this way, we can finally unfold the neutron flux spectrum and determine its absolute intensity. Testing this methodology in a beamline, like Vesuvio, where independent neutron flux measurements are available and can be used as a benchmark, is an important step to prove the accuracy and reliability of this experimental techinque.
DOI: 10.5286/isis.e.rb1800063
title: Defects in the Core Oligosaccharide in Gram Negative Bacterial Outer Membrane Models Expose Anionic Binding Sites, A Potential Achilles Heel

description: The outer membrane of Gram negative bacterial is an effective barrier for many harmful agents. We have been developing and testing advanced models of the Gram negative bacterial outer surface to understand the biochemistry of this important biological surface with molecular precision. So how do cationic antimicrobial agents bind to the anionic phosphate groups of the Lipopolysaccharides (LPS) during their membrane disruption activity? Here, using neutron reflectometry we intend to induce holes in the core region of a model asymmetric gram negative bacterial outer membrane and, using a new titration technique we have developed, examine the Debye screening lengths of the electrostatic bonds formed between a cationic antimicrobial protein (colicin N) and the anionic phosphate groups of the core oligosaccharides of LPS. We hypothesise that the holes allow for short range electrostatic bonds.
DOI: 10.5286/isis.e.rb1810165
title: Neutron Compton scattering investigation of hydrogen defects in Al2O3/Al hydrogen barrier layers on stainless steel

description: The need for structural materials that can resist hydrogen assisted degradation becomes critical for the continuation of the development of the hydrogen economy. Understanding reasons for the occurrence of remaining H-permeability in a duplex steel/Al/Al2O3 system by measuring the concentration of hydrogen is of crucial importance in this context. In this work, it is proposed to carry out a mass-selective NCS experiment concurrently with neutron diffraction on a series of duplex steel/Al/Al2O3 samples to calculate the concentration of hydrogen within the sample and hence the underlying reasons for the occurrence of remaining H-permeability of the barrier with changing environmental conditions such as temperature and pressure.
DOI: 10.5286/isis.e.rb1810228
title: Protein interactions at solid-liquid interfaces: The effect of affinity columns on protein structure

description: Biopharmaceuticals are manufactured using chromatographic procedures including adsorption and desorption processes at the solid-liquid interface. These events take place in porous particles packed within a column. The separation is carried out under plug flow conditions, which allows the high surface area within the particles to be utilised.  The traditional indirect method to measure intra-particle pore structure lacks the resolution to identify how proteins bind to these complex structures.  In this application, we wish to extend initial proof of principal work which has demonstrated the use of SANS, to uncover the heterogeneous pore distribution and the sequence in which they are occupied during a chromatographic process. Our experimental design will enable us to model this and to measure the resin structure before and post adsorption with the therapeutic antibody.
DOI: 10.5286/isis.e.rb1810489
title: Structural and mechanistic study of nanocapsule / hydrogel composites for drug delivery applications

description: The targeted delivery of non-water soluble drugs for applications such as cancer remains a major challenge. Nanocapsules are new materials that can act as a depot for such drugs and release them in a controlled manner; however, they are difficult to keep in the location where drug delivery is desired. We are exploring the use of a fibrillar network, a self-assembled hydrogel, as promising means to act as a depot for the nanocapsules. While the hydrogel itself cannot control the release of the drug, it is able to 'trap' the nanocapsules and keep them at the site of action.While promising, this approach is relatively new and little is known about the interactions between nanocapsule and the hydrogel fibres. This work aims to gain critical insight into these interactions essential to the ability to design the composite material for optimised stability and drug delivery performance
DOI: 10.5286/isis.e.rb1820113
title: The application of INS to examine a Fischer-Tropsch-to-Olefin catalyst that has been reacted in the presence of CO2.

description: In conjunction with an industrial partner (Sasol Technology UK), the applicants have previously used INS measurements performed on the MAPS spectrometer to characterize a series of iron based Fischer-Tropsch synthesis catalysts after various regimes of reaction testing. Most recently (RB1610413 + RB1810122) the programme of work has been extended to examine the Fischer Tropsch-to-olefins (FTTO) process, which requires the addition of specific chemical promoters to shift the product distribution from high molecular weight linear alkanes to low molecular weight olefins. This proposal seeks to use INS to examine the nature and form of the hydrocarbonaceous overlayer associated with time-on-stream for a test reaction (CO hydrogenation at 623 K) that includes the use of CO2 in the feed stream.  This arrangement closely mimics the FTTO industrial scenario.
DOI: 10.5286/isis.e.rb1820118
title: Studies of catalyst-substrate interactions in an industrial ZSM-5 cracking catalyst

description: ZSM-5 zeolites are used as additives in Fluidised Catalytic Cracking (FCC) units to increase the yield of LPG alkenes by conversion of gasoline-range hydrocarbons, forming a key link in the supply chain of these important feedstocks. Improving their yield is therefore a favoured route for meeting the current shortage of propene in the global petrochemicals market. The structure and acidity of the ZSM-5 are known to change over its catalytic lifetime due to steam dealumination of the framework. These changes have been observed to result in significant differences in the interactions between catalyst and substrate between fresh and steamed zeolite. This proposal aims to compare the behaviour of propene and a model gasoline-range alkene (1-octene) when introduced to a simulated industrial ZSM-5 FCC catalyst to those previously observed for a moderately steamed zeolite (RB1810123).
DOI: 10.5286/isis.e.rb1820133
title: SANS studies of the micellar structure of C12-L-Carnitine and C14-L-Carnitine in water under different pH and ionic strength

description: Acyl L-Carnitines are a group of novel surfactants with attractive physical and biological properties associated with their head group charge features. This work proposes to use SANS as the unique technique to determine the size and shape of surfactant micelles as a function of surfactant concentration and the subsequent changes upon pH and ionic strength. The aim is to understand how changes in head group charge affects micellar size, shape and charge characteristics.  We request 3 days of LOQ  beamtime to complete the proposed measurements.
DOI: 10.5286/isis.e.rb1820157
title: Probing Dirac magnons in a honeycomb ferromagnet

description: Studying bosonic analogues of fermions in topological electron systems is one of the hottest areas. They are featured by linear band crossing points at finite energy in the momentum space, topologically protected by symmetries. Since the excitations near these points can be described by Dirac or Weyl equations, these points are dubbed as Dirac or Weyl points, respectively. Topological bosons have been realized in artificial systems, e.g., phononic and photonic crystals. In contrast, although there are many theoretical proposals, real materials supporting topological bosonic excitations are rare.  Recently, our group has observed the Dirac magnons in a three-dimensional antiferromagnet Cu3TeO6. This success encourages us to search for more systems that host topological magnons. In this proposal, we want to study on the topological magnon exctations in a honeycomb ferromagnet CrBr3.
DOI: 10.5286/isis.e.rb1820373
title: The chemisorption of hydrogen on cobalt

description: Cobalt based catalysts are widely used within industry for Fischer-Tropsch synthesis (FTS) in the production of sulphur free diesel. Despite the wide application of cobalt catalysts, there is surprisingly little understanding as to how the hydrogen is partitioned within the catalyst. Previously, we have used INS to examine the chemisorption of hydrogen on a supported cobalt catalyst (Co/SiO2) [RB1720059]. The catalyst support over-complicated the INS spectra making it difficult to assign peaks associated with hydrogen on cobalt. After much difficulty we have obtained a source of Raney cobalt and therefore propose to use INS to investigate the chemisorption of dihydrogen on Raney cobalt as this will provide information on how the hydrogen is adsorbed onto the surface without complications arising from the support material. This will then be compared to the industrial Co/SiO2 catalyst.
DOI: 10.5286/isis.e.rb1820591
title: SXD investigation of post pressurised Cs2CuCl4

description: Cs2CuCl4 has been extensively studied using neutron scattering, and has revealed a quantum spin liquid phase below 2.8 K with antiferromagnetic interactions, and long range magnetic order below 0.62 K. Intriguingly, it has now been shown that when single crystals are subjected to 5kbar of hydrostatic pressure for 2 days, upon releasing the pressure, long range magnetic order is instead observed up to 9 K, yet X-ray diffraction has revealed no clear structural changes. Potentially post-pressurised Cs2CuCl4 is less frustrated with a more quasi-one-dimensional antiferromagnetic spin 1/2 ordered magnetic state, and therefore we aim to investigate the effects of post pressurisation on the crystallographic and magnetic structures using SXD.
DOI: 10.5286/isis.e.rb1900010
title: A single-crystal sapphire cell for in situ powder diffraction on a TOF spectrometer

description: Many technologically important processes from ore smelting to hydrogen storage and the synthesis of functional materials rely on solid-gas reactions. Following these reactions in situ (under gas pressure and increased temperature) allows to unravel their basic steps and helps to gain better control over the processes. We have constructed a gas-pressure cell based on a single-crystal sapphire tube as sample holder for in situ studies. The key idea is to completely avoid background contribution of the container (sapphire) in the experiment by proper orientation of the cell. This will eliminate Bragg peaks from the container material and increase data quality considerably. If tested successfully, the single-crystal sapphire cell may be used at ISIS for in situ investigations on a variety of solid-gas reactions.
DOI: 10.5286/isis.e.rb1600013
title: Origins of a potentially new phase transition in BiFeO3
DOI: 10.5286/isis.e.rb1600047
title: DINS study of proton quantum dynamics of water across 315 K
DOI: 10.5286/isis.e.rb1610018
title: Structure and Magnetism in 2D and 3D Ln2O2MxSe2 Materials

description: We have recently been able to prepare an exciting new family of infinitely adaptive layered Ln2O2MSe2 phases with controllable transition metal architectures that determine their electronic and magnetic properties. In this proposal we request time to study the 2D Fe1xZnx system in which the structure evolves on doping influencing magnetic order. Weve have also been able to produce mixed-metal compounds in which we can order transition metals along the stacking sequence. We have good X-ray evidence for this order in La2O2Cu2xCd24xSe2 and need to investigate this in some interesting transition metal containing analogues.Finally we have recently unravelled the magnetic structure of the 3D polymorph of Ce2O2FeSe2. We wish to study the magnetic structures of the analogous 3D La and Fe/Mn systems.  The work forms part of Chris Ainsworth's PhD studies.