cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5286/isis.e.rb1520064
title: The origins of surface activity in naturally occurring surfactants

description: The biobased economy growing substantially and pressure to reduce reliance on palm and crude oil derived materials, demand that Home and Personal Care industries 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. Saponins are naturally occurring glycolipids with between one and 5 sugar groups as headgroups and are of growing interest as natural detergents. We wish to understand the role of the major components of these naturally occurring mixtures by studying the adsorption behaviour of each isolate with a model conventional surfactant.
DOI: 10.5286/isis.e.rb1520086
title: Resolving the crystal field scheme for Dy3+ in DyNiAl4

description: The  intermetallic series RNiAl4 (R = rare earth) exhibit interesting low temperature magnetic behaviour including a variety of (in)commensurate magnetic phases and metamagnetic transitions. The large inverse magnetocaloric effect observed for TbNiAl4 offers potential for low temperature magnetic cooling and it is expected that the strong magnetic anisotropies are driven by the crystal field (CF) interaction. Recent efforts to characterise the CF using inelastic neutron scattering (INS) have been directed at ErNiAl4 as with J=15/2 the orthorhombic environment results in 8 doublets, enough to determine the 9 symmetry-allowed crystal field parameters, although to date this has not produced a unique set of parameters. To complement studies of Er, we propose to perform a detailed study of DyNiAl4 which is also J=15/2 with the aim of solving the crystal field.
DOI: 10.5286/isis.e.rb1520147
title: Neutron spectroscopy study of the C-H vibrational modes in defective graphene

description: We have conducted an extended study of hydrogenated defective graphene, synthesized by chemical routes (hydrogenated thermal exfoliated graphite oxide or H-TEGO), including neutron scattering, DFT-simulations, uSR, optical spectroscopy and NMR. Our investigations have evidenced the capability of defects in dissociating the molecule of H2 and trapping H atoms in C-H covalent bonds. Moreover, NMR data have evidenced an unexpected hydrogen mobility at relatively low temperatures, associated with a small activation energy. To go further in data interpretation and modeling, we would like to complete our study by measuring a high resolution vibrational spectrum of H-TEGO, to be compared to other nano carbons as reference. For this reason we request 4 days on Tosca.
DOI: 10.5286/isis.e.rb1520204
title: Residual Stress Measurement of Weld Repaired IN718 by Neutron Diffraction

description: Repair welds are usually introduced into structures either to remedy initial fabrication defects in castings or welds, or to rectify in-service degradation of components and thereby extend their life and economic operation.  There is a strong desire in the aeroengine industry to maximise the useful life of components, and repair strategies are becoming an increasingly common to increase the service life of aeroengine components.  This work will form part of a project to develop a validated numerical modelling methodology that can be applied to the weld repair of aeroengine components, allowing parametric investigations to be carried out and optimum repair strategies to be determined. The objective of this proposal is to measure the residual stresses in two IN718 thick plates subjected to an initial weld pass and a repair respectively to allow the validation of the model.
DOI: 10.5286/isis.e.rb1520225
title: Low temperature adsorption of model binary surfactant mixtures in the presence of electrolytes

description: We wish to extend previous studies on the adsorption of binary surfactant systems at the air water interface by the addition of NaCl and CaCl2: mimicking the 'hard water' environment. The focus will be on looking at the change in adsorption as the temperature is dropped from 25oC to 10oC as these low temperature systems are poorly understood; previous experiments show a very significant change in adsorption of certain non ionic/anionic mixtures, which this proposal hopes to further understand. The addition of these electrolytes and their effects on the proposed surfactants have been extensively studied at 25oC, typically showing a decrease in the area per molecule and increased surface activity.
DOI: 10.5286/isis.e.rb1520393
title: A deuteration study aiming to highlight side chain dynamics in crystaline PCBM

description: Fullerene and its derivatives have become materials of great technological interest due to their growing success as electron acceptors in organic photovoltaic cells (OPVs). Despite this success, there is still a very poor understanding of the structural and dynamical properties of these materials. Following a successful QENS study on OSIRIS on pure PCBM, and an express run on TOSCA in 2014 this proposal seeks to extend our study by looking at deuterated samples of PCBM in order to understand the details of the vibrations of side chains  of PCBM. This investigation will be complemented with computational simulations to get detail assignments of vibrational modes.
DOI: 10.5286/isis.e.rb1520441
title: Spin waves in the single layer half doped manganite Pr0.5Ca1.5MnO4

description: We propose to measure the spin wave dispersion and intensities throughout the Brillouin zone of the single layer half-doped manganite Pr0.5Ca1.5MnO4, whose ground state has the canonical CE antiferromagnetic charge- and orbitally-ordered (CO-OO) structure characteristic of so many half-doped manganites.  In contrast to the half-doped 3D manganites with the same sequence of CO-OO and AF transitions and La0.5Sr1.5MnO4, for example, there is evidence that the AF order competes with the CO-OO state. From the spin wave measurements we will determine if indeed the AF super-exchange is anomalously large and if there is strong spin-lattice coupling. We will also compare with our spin wave measurements in the 3D and bilayered analogues of this single layer manganite.
DOI: 10.5286/isis.e.rb1520468
title: Surface properties of nanodiamonds produced by the laser assisted technique

description: Diamond nanoparticles (nanodiamonds) are a constituent of diverse systems including interstellar dusts and meteorites or carbonaceous residues of detonation. Nanodiamonds have a wide range on applications as engineering materials. New production methodology is now opening new potential applications which include drug delivery and bioimaging. The nature of the surface determines how the particle behaves. Unfortunately, the coat is poorly understood, with models and some experimental evidence giving contradictory results. However, the infrared spectra is dominated by modes assigned to oxygenated functionalities and the Raman spectrum only shows the diamond core. INS spectroscopy is essentially ?blind? to both carbonyls and the core, thus it offers the possibility of new information about the surface hydrogen structure.
DOI: 10.5286/isis.e.rb1540016
title: NTC2015
DOI: 10.5286/isis.e.rb1610119
title: Oxidation of thin film at the air-water interface of cloud droplets using REAL atmospheric aerosol from polar, marine and urban sources

description: The Earth's climate is strongly influenced by clouds. The oxidative processing of pollutants in clouds affects droplet size and optical properties, important effects. Common cloud pollutants are naturally occurring organic surfactants forming organic films on the droplet, The climatic effect depends on the rate of atmospheric oxidation of these films and whether any product film forms. In this work we will study the kinetics of hydroxyl radical with insoluble surfactants from samples from Antarctica, mid-Atlantic and Urban London. Specifically we will (a) demonstrate that an aqueous cloud oxidant, the OH radical, can oxidise a real atmospheric organic film with different provenances, b) calculate the effect of the reaction on the hygroscopic properties of a cloud droplet and demonstrate removal of the organic film may cause a cloud to evaporate (c) Support an STFC futures grant.
DOI: 10.5286/isis.e.rb1610216
title: Varying oxygen content in the quantum spin ice Tb2Ti2O7

description: Tb2Ti2O7 is one of two compounds identified as potential quantum spin ices. As with other oxide pyrochlores the properties depend sensitively on the oxygen stoichiometry. Most previous studies have aimed to work with samples as close to being stoichiometric as possible. In proposal 1520281 we studied oxygen-deficient and stoichiometric samples with muons, and established a change in the observed signal. Fridge measurements on the oxygen-deficient sample were approved but have not yet been run. We now propose to complete the study by measuring the stoichiometric sample at fridge temperatures and an oxygen rich sample at fridge and cryostat temperatures.
DOI: 10.5286/isis.e.rb1610287
title: Searching for a core-shell or multi shell structure in Stöber silica particles

description: We want to measure the SESANS from a series of large ~1 micron silica particles formed using the multistage Stöber method. The reason for this is to determine if we can see the mutli-shell structure which has been postulated recently based on transmission electron microscopy measurements.
DOI: 10.5286/isis.e.rb1610355
title: Short and long-ranged magnetic order in the new isotropic S = 1/2 kagome ferromagnet ND4Cu2.5V2O7(OD)2.D2O

description: Exotic electronic states are of great interest to fundamental science, such as the quantum spin-liquids (QSLs) which were theorised to behave like a sea of resonating spin states without preferential ordering, analogous to the liquid state. The best candidate materials for 2 dimensional QSLs are kagome magnets where the atomic magnetic moments make up a vertex-sharing lattice of triangles. While research has typically focussed on quantum S=1/2 kagome antiferromagnets, here we propose to study a new S=1/2 kagome ferromagnet, ND4Cu2.5V2O7(OD)2.D2O, which shows evidence of competing magnetic interactions and magnetic frustration, the classic situation for QSL formation. We propose to use WISH to study short- and long-ranged spin structures and so to determine the role that frustration plays in its ground state properties.
DOI: 10.5286/isis.e.rb1610467
title: pH-control of swelling and charge neutralization of thin hydrogel films

description: Hydrogels are widely used in biomaterials science, much due to excellent protein resistance, and physicochemical properties similar to biological tissue. Charge neutrality is essential for protein resistance, and can be achieved with uncharged hydrophilic polymers, but also zwitterionic and other charge-compensated materials are effective in this respect. The presence of a large number of ionizable groups facilitate strong ionic hydration, reducing protein adsorption. However, the neutrality is pH-sensitive, and antifouling properties might not be retained if the pH is changed. We have exploited this pH-sensitivity to develop coatings with pH-tunable protein resistance, formed from layers of oppositely charged polymers. However, our understanding of the charge-neutralization, and the precise relation to polymer composition and intermixing is limited, and will be addressed in this study.
DOI: 10.5286/isis.e.rb1610513
title: Role of DMSO in Ionic Liquid / DMSO Mixtures

description: This proposal aims to study the interactions within a prototypical ionic liquid / co-solvent system. Such systems are currently under investigation as potential solvating media for biomass (e.g. cellulose) reprocessing, wherein the ionic liquid provides the strong interactions required to solvate such difficult to dissolve natural polymers, and the  co-solvent serves to reduce the viscosity of the overall system.  The use of co-solvents for ionic liquids is also commonplace when performing NMR studies on ionic liquid systems, since usage of the neat ionic liquid is impractical. Many contrary viewpoints exist in the literature as to the interactions present between the co-solvent and the ionic liquid, ranging from "no significant interaction" to "full ionic separation of the ionic liquid". The present experiment aims to clarify the interactions present in these systems.
DOI: 10.5286/isis.e.rb1620049
title: Bio-inspired Ionic Liquids for Lignin Dissolution

description: Biomass is a renewable source of fuel and fine chemicals. Although naturally abundant, it is heterogeneous and recalcitrant to biodegradation. Current industrial strategy is to separate individual components before conversion. A major challenge is to find low-cost solvents with optimized extraction efficiency.Ionic liquids (ILs) are salts that melt near room temperature. Bio-based ILs, such as cholinium lysinate, are non-toxic, renewable and inexpensive. They are the next generation of sustainable solvents for lignin extraction. We will examine the structure of mixtures of ILs with model lignin residues and water. This will enable us to understand the dominant intermolecular forces during the extraction process, and the influence of IL structure on extraction efficiency. This structural insight will facilitate future design of sustainable solvents for biomass processing.
DOI: 10.5286/isis.e.rb1620112
title: Probing the effect of hydrophobic end chain length on the interaction of hydrophobically modified polymer with sodium dodecyl sulphate.

description: Polymers are used to increase the viscosity of formulations to impart beneficial characteristics. To minimize the amount of polymer needed, polymers that form gels through aggregation of grafted hydrophobic groups are employed. These so-called associative polymers do however, interact with the other formulation components e.g. surfactants & particles. Thus, formulation can be challenging. Here, we study the interaction between two common components, a series of ethylene oxide based urethane polymers and the surfactant sodium dodecylsulphate. Competitive interactions between surfactant and hydrophobic moieties on the polymer lead to complex composition dependent behaviour. This study sets the background to two other proposals where we wish to examine the impact of added particles of varying surface composition. Together, these studies represent a detailed study into complex mixtures.
DOI: 10.5286/isis.e.rb1620129
title: Multilayering of Methyl Ester Sulphonates at the Air-Aqueous Interface: Effect of Counterions

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 renewable from palm oil and we have shown that they have the interesting ability to form multillayers. We propose to examine the effect of the calcium(magnesium)/aluminium balance on the multilayering phenomeno
DOI: 10.5286/isis.e.rb1620206
title: Quantitative analysis of precipitate coarsening in V and V-Mo microalloyed steel

description: Ever-more stringent environmental regulations have driven the automotive industry to continuously develop lightweight solutions in automotive body sheet materials, without compromising of passenger safety and manufacturing robustness. Steels with small amounts of alloying elements such as vanadium, molybdenum (also called micro-alloyed steels) strengthened via nano-precipitates, are potential candidate materials fitting these requirements. To be able to control the dispersion of nano-precipitates and understands its effect on mechanical properties, a detailed understanding of their formation and growth kinetics at the nanoscale is essential. This proposal is a part of an ongoing EPSRC funded (£600K from Sep. 2014-Sep. 2017) project, which aims to develop new micro-alloyed steels with enhanced strength. This project is collaboration between the University of Warwick and Tata steel.
DOI: 10.5286/isis.e.rb1620317
title: Amino-Acid Based Surfactant Monolayers on a Range of Subphases

description: Amino acid based surfactants have been known for many years but so far few detailed studies have been carried out on their properties. We are using amino acids extracted from grain residues, otherwise used in animal feed, to prepare surfactants with amino-acid based headgroups. We aim to evaluate whether such feedstocks could provide a renewable source for such amphiphiles for use in emulsification, and formulations for delivery of active species. Here we propose a preliminary reflectivity study using neutron and Xray reflectivity to study monolayers of three amino acid based surfactants on a range of subphases to determine their structure & behaviour at interfaces for comparison with petrochemically derived surfactants. The goal is to determine the structure of these compounds on a range of subphases relevant to their applicability to use in formulations and cleaning products.
DOI: 10.5286/isis.e.rb1620452
title: Delivery of Mixtures of Volatile Organic Compounds by Capillary Condensation into Monolithic MCM-41

description: Condensation is the phenomenon of turning vapour into liquid, and this happens differently in open and confined spaces. The latter occurs under lower vapour pressure, and is a common phenomenon in porous media, known as capillary condensation. It is a popular way for delivering compounds when no excess of liquid phase in the solid porous sample is required.This proposal aims to establish a reliable and reproducible protocol for filling a porous material with binary mixtures with a desired ratios of compounds. Neutron diffraction, which delivers structural information of the bulk material and the confined fluids within, finds it difficult to determine the chemical composition of the complete system.  Establishing a reliable means for depositing known ratio mixtures of vapours into porous materials is crucial in furthering research in, e.g. catalysis, nanosensing, and nanoseparations.
DOI: 10.5286/isis.e.rb1410629
title: Residual stress measurements on W-W joints for nuclear fusion applications

description: Materials of interest for nuclear fusion applications (like for instance W and W alloys) require special properties in terms of mechanical resilience and radiation hardness. Components like W-W and W-steel joints have to be characterised for such applications, also in terms of residual stress induced in the brazing in different conditions of preparation. However, there is a lack of data about residual stress in W-W and W-steel brazing. We propose to perform a series of measurements on W-W joints realised by brazing in different conditions. Such joints are prepared by King Juan Carlos University in Madrid and they are part of a wider research and characterisation activity in the field of fusion materials under the EFDA coordination.
DOI: 10.5286/isis.e.rb1520088
title: Density-driven structural transformations in magnesium silicate glass

description: The density-driven structural transformations in the magnesium silicate glass MgSiO3 will be investigated at pressures increasing to 17.5 GPa. This glass is one of a family of geophysically important silicate materials that form a significant component of the Earth's mantle. As the density is increased, a disruption of the tetrahedral silicate network is expected to be observed as the Si-O coordination number starts to increase above four. The results will be used to inform molecular dynamics models of MgSiO3, a material that is used as a reference for simulating the high-pressure behaviour of hydrous silica melts under geophysical conditions. If necessary, new interaction models will be developed for deducing the mechanisms of network collapse.
DOI: 10.5286/isis.e.rb1520098
title: The high pressure structure of cobalt-bearing silicate glasses

description: The aim of this proposal is to examine the pressure induced changes in the structure of two cobalt-bearing silicate glasses. Transition metals such as cobalt can adopt different structural roles depending on their valance state. Cobalt-bearing glasses synthesised under different oxygen partial pressures will be used for this experiment, studies of these glasses have shown that different valance states are accessed and the structural role of Co3+ and Co2+ is very different. The aim of this work is to evaluate how theses differently modified amorphous structures behave under pressure. Building on previously successful experiments at ISIS this work will involve study of two glass samples (with different amounts of Co2+ and Co3+) with diffraction patterns measured at 10 and 17GPa.
DOI: 10.5286/isis.e.rb1520192
title: A High pressure investigation of the Manganese Carbonyls Mn(CO)5(CH3) and Mn(CO)5Br

description: Organometallic compounds play an important role in catalysis, and compounds with metal carbonyl groups have been studied at elevated pressure by vibrational spectroscopy, but corresponding diffraction studies are rare. We will investigate as a function of pressure the octahedral complexes Mn(CO)5R ( R = CH3 or Br) which are known to undergo pressure dependent phase transitions. Our objectives are: 1 to determine the structures of both compounds in their high pressure phases, 2 To show how these metrical parameters in these molecules change with pressure. 3. To obtain information of possible mechanistic pathways of the reactions of these molecules, by observing how the molecule deforms with pressure 4. To compare the effect of changing the electronic demand at these metals centres affects their response to pressure. 5. To obtain compressibility data on the high and low pressure phases.
DOI: 10.5286/isis.e.rb1520266
title: Alkali ions dependent collective excitations in borate glasses

description: Recently, it has been suggested that the First Sharp Diffraction Peak (FSDP) in glasses arises from a quasi-periodicity of void spaces in the structure, that plays the role of the lattice spacing of crystals, and  that the Boson Peak (BP) in glasses could result from a piling up of the vibrational states near the boundary of the pseudo-Brillouin zone (PBZB).We propose to identify the contribution of collective excitations along the position of the PBZB in two borate glasses, characterized by different FSDP and BP positions, in order to verify if the FSDP acts as a sort of Brillouin zone center for glasses and if the observed BP arises from the piling up of the vibrational states near the related PBZB.Considering the kinematic range of interest, the MARI spectrometer is suited to enable a successful experiment.We request three different incident neutron energies and a beam time of 4 days.
DOI: 10.5286/isis.e.rb1520269
title: How does a catalyst promoter affect the degree of hydrogen retention of iron-based Fischer-Tröpsch catalysts?

description: We have recently used INS to determine how a hydrogen pre-treatment stage of an iron based Fischer-Tropsch catalyst may modify catalytic performance.  That work established how critical the form of the catalyst activation procedure is in determining the sustainability of desired catalytic turnover.  This new study builds on those findings and considers how a certain catalyst promoter (potassium) can modify the chemical form of the hydrocarbonaceous overlayer that is thought to control selectivity.  The work is novel and will provide new information that is not readily obtainable by any other technique.