cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1520494
title: Muon spin relaxation study on Sr2TIrO6 (T = Ca, Mg, Sc and Lu) to understand the nature of magnetic interaction in double perovskites

description: In recent times iridates have become a fertile ground for studies of new physics driven by strong spin-orbit coupling that is analogous to the on-site Coulomb and crystalline electric field interactions. This exceptional occurrence generates a subtle balance between interactions that drives complex magnetic and dielectric behaviours and exotic states rarely or never seen in other materials. Magnetic measurements indicate an antiferromagnetic ordering below 58 K for Sr2CaIrO6 and 74 K for Sr2MgIrO6. Neutron diffraction shows the long range ordering in the former, but not in the later. The study of µSR will be important to understand the magnetic anomaly observed in the magnetiztion data. We propose to study the microscopic magnetic nature of these compounds by means of µSR, which is very sensitive to the local magnetic and structural environments.
DOI: 10.5286/isis.e.rb1620001
title: The icy-moon analogue of MgSiO3-perovskite: MgSO4.9H2O  a high-pressure study

description: Mg-sulfate 11-hydrate (meridianiite) is decomposed by pressure to form Mg-sulfate 9-hydrate + ice, a process that will occur in the mantles of large icy planetary bodies and have the same impact as olivine's decomposition to Mg-silicate perovskite + MgO in the Earth's mantle.It is necessary for accurate modelling of planetary interiors to determine the high-pressure behaviour of Mg-sulfate 9-hydrate, which includes measurement of its incompressibility (K), as well as the pressure and temperature dependence of K, and characterisation of any phase changes. Some sparse and low-quality data already obtained, combined with DFT calculations, indicate a bulk elastic softening above 1 GPa that may indicate a further phase transition or dehydration. I propose to carry out a gas-cell study on OSIRIS (0-550 MPa, 100-240 K) and a Paris-Edinburgh cell study on PEARL (0-5 GPa, 100-380 K).
DOI: 10.5286/isis.e.rb1620003
title: Thermal expansion of kyanite, andalusite and sillimanite

description: Al2SiO5 forms three naturally-occurring polymorphs, kyanite, andalusite and sillimanite. These minerals are produced by varying degrees of metamorphism of sedimentary rocks, the polymorph (or mixture of polymorphs) produced being diagnostic of the P/T path followed. Use of these key petrological indicators is dependent on a firm thermodynamic description of their properties and behaviour. Characterisation of the thermal expansion is a central part of this thermodynamic description.The thermal expansion of kyanite, andalusite and sillimanite have only been measured above room-T and largely using X-ray powder diffraction methods. This limits the accuracy and precision of the thermal expansion tensor coefficients and prevents us from being able to parameterise the thermal behaviour in terms of fundamental thermodynamic quantities. The aim of this proposal is to correct these deficiencies.
DOI: 10.5286/isis.e.rb1620119
title: Detailed characterisation of metastable phase fractions in ZrW2O8

description: Cubic alpha-ZrW2O8 is the classic example of a material exhibiting the unusual property of negative thermal expansion (NTE). Despite this effect having been discovered 20 years ago, it is not well understood. NTE is widely thought to arise due to correlated libration of large rigid structures, but the details are far from clear. Recent theoretical work has concentrated on determining which phonon modes contribute most to NTE. We have already obtained inelastic neutron scattering data in an attempt to test these calculations. However, we discovered that an unknown fraction of our sample contains the metastable orthorhombic gamma phase of ZrW2O8, which displays much weaker NTE. We wish to characterise the phase fractions in our samples, which will allow us to tell if our INS data can be easily analysed. We will also heat-treat the samples in-situ to recover phase-pure alpha ZrW2O8
DOI: 10.5286/isis.e.rb1620122
title: Interaction of lignosulphonates with model surfactant systems by neutron reflection

description: With the biobased economy growing substantially and pressure to reduce reliance on palm and crude oil derived materials, it is vital that the Home and Personal Care industry develops frameworks for deploying sustainably sourced alternative materials. Lignin is naturally abundant and an integral part of the secondary structure of plant cell wall structure. It is often simply burned as a waste product. With such an abundance of this material it is beholding on responsible innovation to find applications for waste derived materials. Certain lignin derivatives are finding limited application in heavy industry and in crude oil recovery. Their properties are not well understood and this study is attempting to understand how they behave in an environment more close to Home and Personal Care, in order to assess their future potential for deployment.
DOI: 10.5286/isis.e.rb1620125
title: Copy of: The origins of Biosurfactant self synergy

description: Biosurfactants are becoming more commonplace in pharmaceuticals, vaccines and other forms of medicines. With the biobased economy growing substantially and pressure to reduce reliance on palm and crude oil derived materials, it is vital that the Home and Personal Care industry develops frameworks for deploying sustainably sourced alternative materials. Biosurfactants tend to be very similar to nonionic and mild anionic surfactants but with significantly higher molecular weights, generally more than double that of the most commonly used conventional surfactants. We have observed that like their synthetic counterparts these molecules self assemble into liquid crystalline like structures and the aim of this work is to progress towards understanding the way that the molecular architecture drives this mesostructure formation.
DOI: 10.5286/isis.e.rb1620178
title: The PVT equation of state of D2O ice III / IX

description: The high-pressure form of solid water, ice III, is the equilibrium phase in contact with liquid water at pressures from about 2.0 - 3.5 kbar. Consequently, its properties are important in calculating the volume changes on freezing of subsurface oceans inside icy planetary bodies and the buoyancy of icy volcanic melts. The incompressibility (bulk modulus) of ice III as found by quantum mechanical simulations is much lower (&lt;60%) than that of the ice phases at neighbouring pressures and temperatures, but the very small stability field of ice III makes its experimental determination difficult. We have a few measurements within its stability field from a recent OSIRIS experiment, and we now intend to combine these with measurements on metastable ice III (= ice IX, when proton ordered) to much higher pressures on PEARL to obtain both the incompressibility and its temperature dependence.
DOI: 10.5286/isis.e.rb1620308
title: High-pressure studies of methyl stearate

description: In order to tackle emissions targets for CO2, there is increasing pressure to replace fossil fuels with renewable fuels. Biodiesel is one such renewable transportation fuel that comprises long-chain saturated fatty acid methyl esters such as methyl stearate.  Although biodiesel has many advantages compared to conventional diesel, it suffers from poor performance at high pressures on account of crystallisation in fuel lines and in high-pressure injectors. We are currently investigating the crystallisation of biodiesel under low-temperature and high-pressure conditions, and are using methyl stearate as a model compound.  The aim of the proposed experiment is to use high-pressure neutron powder diffraction to explore the phase behaviour of methyl stearate. This will contribute to the development of crystal-habit modifiers that prevent blockage of fuel lines under high-pressure conditions.
DOI: 10.5286/isis.e.rb1620326
title: Depth profiling in PbMg1/3Nb2/3O3 using muons  Origin of skin effect?:

description: We propose to use muon depth profiling to characterize chemical homogeneity near the surface in a relaxor ferroelectric - PMN.  PMN displays a distinct skin effect which may originate from chemical inhomogeneity or clustering.  Alternatively, random field theories based upon model magnets have been suggested.  We propose to test this possibility using muons.
DOI: 10.5286/isis.e.rb1620400
title: How do rotational motions alter the local potential of nanoscopic molecules? (A c60 case study)

description: C60 represents the prototypical case study for a highly geometric nanoscopic entity that exhibits exotic dynamical and thermodynamic transitions. Yet little in general is known about the sensitivity of local potentials/momentum distributions to such transitions. As such we propose a set of deep inelastic neutron measurements aiming to act as a testbed of understanding in this area, which may be extended to the class of highly "in vogue" fullerene derivatives which show great technological promise in the organic photovoltaics, and have been shown to allow tunability through disorder.
DOI: 10.5286/isis.e.rb1661003
title: ND and NRCA as diagnostic tools in musical cultural heritage:the case of a well preserved Italian metal organ pipe, dated XVII-XVIII century
DOI: 10.5286/isis.e.rb1510042
title: The physics of detergency at low temperature: neutron reflection to reveal surfactant surface compositions from model binary mixtures

description: Although surfactant detergency is well understood above 30 C, actions of surfactants below 30 C are not well established. In the era of energy saving and environment caring, we must understand how to optimise detergency in what are increasingly hostile environments. Existing surfactant mixing theories such as regular solution theory are not validated at low temperatures, and other factors such as being closer to the solubility limit of the surfactants, and perhaps proximate to phase boundaries also need to be taken into account. It is hence vital that industry is supported with both data and a thermodynamic description of the behaviour of detergent components at ambient and below ambient temperatures. This work proposes to study how model surfactants behave in model binary mixtures below ambient temperatures on the surface of water.
DOI: 10.5286/isis.e.rb1510071
title: Proteins of Different Size and Globular Stability Adsorbed at Oil/Water  Interfaces Studied by Neutron Reflection

description: In this work we explore how to use neutron reflection to study protein adsorption at the oil/water interface. Inter is preferred because we have built technical capability on this instrument. Our specific aims are to (a) determine the actual thickness and volume fraction of globular lysozyme and (b) the effect of pH on the interfacial distribution. The results will enable us to compare the extent of proteins distributed into the oil region between lysozyme and large but less stable BSA at the interface. BSA has a distinct segment distribution in the oil region. The results from lysozyme will enable us to answer if this structural feature is unique to BSA as it contains regions for the delivery of fatty acids and lipids.
DOI: 10.5286/isis.e.rb1510072
title: Studying Electron Freezing and The Emergence of Static Magentic Order in Nb and In-Doped Ruilte TiO2

description: One of the technological goals is to create materials that show high permittivity and low dielectric loss, which has been achieved by the co-doping of Nb and In into rutile TiO2. This is due to the Nb(V) and In(III) inducing a larger number of oxygen vacant sites or defects which can trap an electron and it is this confined electron that has a large polarisability compared to electrons confined to an atom leading to the observed dielectric properties. The trapped state of the electrons is of great interest in understanding the fundamental properties of the material where magnetic ordering is seen to emerge at low temperature due to a freezing of the electrons within the defects. Muons can provide a great advantage for studying weak magnetic systems and it is hoped they will elucidate information on the electron freezing and magnetism.
DOI: 10.5286/isis.e.rb1510325
title: The crucial roles of metal-hydrogen stretches in catalytic hydrogenation on bimetallic catalysts

description: Bimetallic alloy catalysts with optimized metal ratio usually exhibit a superior catalytic hydrogenation activity and selectivity compared to individual mono-metallic catalysts, which has been attributed to the geometric and electronic structure of the alloy in H2 activation. The adsorption properties of small molecules depend on the electronic structure of the surface via i) H2 adsorption, ii) H2 dissociation and iii) H diffusion. The roles of each step in determining the reactivity of catalysts remains unclear. Therefore, an in-depth investigation of the metal-hydrogen stretch would not only provide information on the strength of interaction between hydrogen and metal to help unpack the electronic structure effects, identify the existence of H moieties and unravel the nature of the outstanding activity of the bimetallic catalysts, as well as the role of the catalyst support.
DOI: 10.5286/isis.e.rb1510363
title: Universal Quantum-Critical Dynamics of a Two Dimensional Antiferromagnet

description: We have recently discovered a pressure-induced quantum phase transition (QPT) at 4.3 kbar in the gapped quantum magnet piperazinium hexachlorodicuprate (PHCC) by means of muon-spin rotation and inelastic neutron scattering (INS) measurements. The Heisenberg nature of the spins and the quasi 2-dimensional spin network of PHCC allows, for the first time, the study of SO(3) symmetry breaking in two spatial dimensions. This transition is of particular interest due to the presence of a longitudinal Higgs excitation. Previous INS experiments deep in the ordered phase have allowed us to identify the ordering wave vector. Here, we propose to study the universal scaling of the dynamic structure factor around the ordering vector at the QCP in order to test specific predictions of the so-called non-linear sigma model.
DOI: 10.5286/isis.e.rb1510398
title: The use of INS to evaluate evolutionary processes associated with bringing iron based Fischer-Tröpsch catalysts on-line

description: In collaboration with a major provider of Fischer-Tröpsch synthesis (FTS) catalytic technology, the research team have recently demonstrated how INS can be used to probe iron based FTS catalysts.  This has necessitated refinements in sample environment at the Central Facility, with the studies providing new information on the operational phase of these important catalytic materials.  Against this background, it is proposed to evaluate the effectiveness of INS in providing information on an ¿evolutionary¿ phase of the catalyst conditioning process that is associated with variable rates of reaction.  Monitoring of the INS spectrum of iron based FTS catalysts as a function of extended time-on-stream will make full use of the improved sample environment capability.
DOI: 10.5286/isis.e.rb1510524
title: Crystal electric field excitations of pyrochlore quantum antiferromagnet Ce2Sn2O7

description: We have recently discovered an exotic magnetic state developing at subKelvin temperatures in the Ce3+ pyrochlore stannate. The spin system of this compound is characterized by a thermally isolated Jz=3/2 Kramers' doublet at low temperature, providing small effective moments on a pyrochlore lattice. We have observed that these spins are characterized by a strong Ising &lt;111&gt; anisotropy. The system does not order down to the lowest investigated temperature (70 mK). However, it develops a correlated regime for temperatures below 1 K, due to antiferromagnetic interactions one order of magnitude larger than the expected ferromagnetic dipolar couplings. We propose to explicitly measure the CEF scheme of Ce2Sn2O7 by inelastic neutron spectroscopy in order to confirm the picture of a thermally isolated Kramers' doublet at low temperature.
DOI: 10.5286/isis.e.rb1510581
title: Na ion diffusion in clays for nuclear waste management

description: Clays are porous materials and planned to be used as barrier material in radioactive waste repositories. In this context understanding of water and solute diffusion on different time and length scales is of interest. With this proposal we aim to study Na ion diffusion in clays at the atomic level, where experimental data is completely missing.Our team has previously developed a novel mu+SR method at ISIS to study ion-dynamics in solids, and we are confident to be able to use the same technique also for the current topic. For this we are applying in total for 5 days of beamtime using either the EMU or MUSR spectrometer of ISIS.
DOI: 10.5286/isis.e.rb1610068
title: Structural studies of thermal responsive nanogels at the oil-water interface

description: It has been shown that gel particles are able to stabilize the oil-water interface and forming emulsions ( the so called "Pickering emulsions"). It has also been shown that thermo-responsive nanogels have the similiar ability to stabilise emulsion with the unique advantage of reversibilty on demand. However, very little is known about the underlying mechanisms of the emulsion ability of these nanogels. Here we  would like to study the structural conformation and adsorption mechanisms of thermoal-responsive nanogels at the oil-water to optimise the design of  these new class of emulsion stabilizers.
DOI: 10.5286/isis.e.rb1620009
title: Single Crystal Neutron Diffraction Study of a photo-active pyrene derivative

description: The compound proposed for this study is an interesting example of how strongly spectroscopic properties of pyrene derivatives in the solid state can depend on the crystal packing environment. We intend to study that effect by means of experimental electron density analysis and theoretical calculations. We have already collected high quality, high resolution X-ray data for the compound, necessary to refine aspherical model of experimental electron density. High quality neutron data are necessary to provide an accurate description of molecular geometry, in particular the exact hydrogen atom positions and atomic displacements, that cannot be obtained otherwise. We propose to conduct two single crystal neutron diffraction experiments at 20K and 90K in order to obtain accurate atomic positions and verify the presence/absence of anharmonic vibrations in the molecule.
DOI: 10.5286/isis.e.rb1620127
title: Multilayering of Methyl Ester Sulphonates at the Air-Aqueous Interface: Effect of Molecular Architecture

description: Surfactants usually form a single layer of molecules at the surface of water. We have shown that under certain conditions more than one layer may form. When this happens the system seems to become a powerful wetting agent (it will wet Teflon). A whole range of useful technological properties would follow from this, e.g. more effective detergency, and since the phenomenon seems to be associated with more charged ions such as calcium and aluminium, hard water would enhance detergency in contrast to the usual reduction. It is important to be able to extend this behaviour to more surfactants. There is also a drive to use renewable materials. The methyl ester sulphonates are from the renewable resource of palm oil and we have now shown that they have the interesting ability to form multillayers. We now propose to examine the effect of their molecular structure on the multilayering phenomenon.
DOI: 10.5286/isis.e.rb1620211
title: Fatigue crack propagation effect on the residual stress redistribution of laser cladded rail

description: To improve the railway networks, track components with greater durability are essential. To this end, we clad a layer of premium material on railhead to reduce wear and the likelihood of fatigue in an effective manner. However, the resulting residual stress in the clad and substrate and changes in their microstructure can be detrimental to their integrity. We propose to measure their residual stress to validate our finite element model for both high and low durability specimens. We will sequentially fatigue the specimens and monitor their residual stress at critical points to study shakedown and possible cracking. A drop in residual stress is a surrogate for crack initiation; early detection of cracks allows us to study the crack initiation site and its surrounding microstructure. This will help optimise the cladding parameters to achieve greater clad durability.
DOI: 10.5286/isis.e.rb1620220
title: The Interaction of wild-type and mutant Puroindoline B  with Model Bacterial Membranes

description: Bacterial and fungal infections of cereal crops pose a considerable risk to global food security. Typically plant pathogens are controlled through the use of chemical agents including fungicides and pesticides, to which resistance is becoming widespread. Increasingly attention is now being turned to the role that naturally occurring antimicrobial proteins can play in defence against disease-causing agents. We are studying one such protein, called puroindoline, which is found in wheat. We wish to use neutron reflectivity to understand better how it penetrates the surface of microbial and fungal cells and what controls how it does this in terms of the structure of the protein and of different types of cell surfaces.
DOI: 10.5286/isis.e.rb1620279
title: Cationic surfactants adsorbed to titanium dioxide-effect of pH and added electrolyte

description: Titanium dioxide (TiO2) is used in a wide range of applications from medical and dental implants to treatment of contaminated air and water streams. However many of the applications suffer from limitations of cleaning, separation and recovery after the use. Understanding the interactions of cleaning agents with TiO2 is a great challenge in material science.  The structure of hexadecyltrimethylammonium bromide (C16TAB) adsorbed at various solid/aqueous solution interfaces is unusual as the layers are thin and thus likely to dominated by specific interactions of charged heads and the substrate and solvent. In this experiment we will study the adsorption and structure of C16TAB on titanium oxide and understand the effect of pH and added electrolyte as well as how it can be displaced by rinsing and use of other surfactant.
DOI: 10.5286/isis.e.rb1620323
title: Spin-orbit transitions in Co2V2O7

description: We propose to investigate the magnetic fluctuations and spin-orbit transitions in Co2V2O7.  This material is structurally related to CoV2O6 which displays cascading magnetization plateaus.  This material contains Co2+ which has an orbital degree of freedom and we propose to measure the spin-orbit transitions and compare these to CoV2O6 previously investigated on MARI.  The proposal requests 5 days on MARI.
DOI: 10.5286/isis.e.rb1620339
title: Mass-seective neutron Compton spectroscopy in formic acid: a test of phase polymorphism.

description: Formic acid (FA), HCOOH, is the simplest carboxylic acid. Its two oxygen acceptor sites and two hydrogen bond acceptor sites provide several possibilities for hydrogen bond formation. Thus, it can be regarded as an archetypal molecule for the study of important fundamental phenomena such as hydrogen bond geometry and strength, proton transfer, and polymerization. Based on our ab initio CASTEP predictions for INS and NCS spectra, we propose to test the hypothesis by Zelsmann et al. of the coexistence of the beta1 and beta2 phases above 220 K. NCS spectra will be recorded at T = 10, 200, and 240 K. The widths of NMDs of H, C, O obtained from the experiments will be compared with the results of our ab initio prediction for the beta1 phase. In particular, the degree anisotropy of the measured NMDs will be characterised in terms of the Gram-Charlier expansion (GC) fits to NCS data.