2,109 Works

Neutron diffraction for non-destructive evaluation of composition and microstructure in highly heterogeneous ancient steel from Mongolia

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Recent analytical research on ancient metal objects recovered in Mongolia revealed that the early bronze and iron-making technologies can be clearly differentiated from those practiced in contemporaneous China. The nomadic life style of Mongolian population was not compatible with the production of large size artistic artefacts, typical of urban centres, therefore they developed a tradition of production of high quality transportable small size artistic objects.Iron artefacts recovered in Mongolia often display evidence of small-scale engineering...

Do cardiolipins play a role for the mode of action of antimicrobial peptides? A study using free floating lipid model membranes

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Antimicrobial peptides (AMPs), also called host defense peptides, are part of the innate immune system of essentially all species, from bacteria themselves to mammals to protect against bacterial pathogens. Although the exact microscopic mechanism(s) is still debated, this chemical structure allows them to target bacterial cell membranes which have net negative charge, selectively. One hypotheses of the mode of action is that AMPs interacts with cardiolipins (CL), and important anionic lipid present in bacterial membranes...

Unravelling the source of anomalously large spin Seebeck effect in Fe3O4:Pt bilayer thin films

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The spin Seebeck effect is a newly discovered phenomenon that if harnessed, could result in a significant improvement of the efficiency of thermoelectric energy generators. Spin polarised neutron reflectivity, with the addition of the off-specular information provided by the OSMOND detector, will provide us with complementary measurements that enable determination of the spin polarisation of the film as well as surface morphology at the interface. This is especially important as the influence of the interface...

Unravelling the source of anomalously large spin Seebeck effect in Fe3O4:Pt bilayer thin films

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The spin Seebeck effect is a newly discovered phenomenon that if harnessed, could result in a significant improvement of the efficiency of thermoelectric energy generators. Spin polarised neutron reflectivity, with the addition of the off-specular information provided by the OSMOND detector, will provide us with complementary measurements that enable determination of the spin polarisation of the film as well as surface morphology at the interface. This is especially important as the influence of the interface...

Correlations between crystallographic distributions and mobility of oxide ions in Ba3NbWO8.5

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Oxide ion conductors have been a focus of intense research due to their application as electrolytes in solid oxide fuel cells (SOFCs), devices intended to allow the safe utilisation of hydrogen fuel for energy. Ba3NbMoO8.5 is a pure oxide ion conductor with competitive conductivity at "moderate" operating temperatures, but its highly disordered crystal structure is not well understood. We will use single-crystal neutron diffraction to examine the distributions of oxide ions in the structure as...

SEE response evaluation of robotic systems for the nuclear decommissionning

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With many nuclear power plants coming to the end of their life, the nuclear Decontamination and Decommissioning process needs: cost effective, environmentally friendly and low human risk solutions. A steadily increasing research field is targeting many of the challenges around the D&D such as the inspection of areas that are subjected to ionizing radiation, as well the sorting of the nuclear waste. The experimental campaign that we propose in this request for beam time is...

Study of spin-phonon coupling to understand the multiferroic properties of polar magnetic oxides DyMWO6 (M = Cr, Fe) using Inelastic Neutron

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Polar magnets, an interesting family of compounds both fundamentally and technologically as they exhibit rich variety properties such as magnetism, ferroelectricity, pyroelectricity, magnetodielectric/electric effect, and multiferroicity. Recently, we reported new polar magnets DyMWO6 (M = Cr, Fe) crystallize in orthorhombic structure with space group Pna21 exhibit interesting magnetic and magnetoelectric properties. DyFeWO6 compound shows spin induced multiferroicity whereas DyCrWO6, not a multiferroic. However, the origin of the interplay between magnetism and ferroelectricity remains unsolved in...

Can identical crystals melt into two distinct liquids?

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Seemingly identical molecular crystals of acetaldehyde phenylhydrazone (APH), C8H10N2, are reported to melt to liquids with distinctly different structures, and with different melting points of between 60 and 100 C. The low- or high-melting forms can be reliably prepared by exposure of crystals to trace acid or base (as little as 1/1000th molar equivalent) respectively, with no detectable change to the crystal structure. Although rare, this remarkable and strange behavior demands further investigation. It has...

Magnetic field effect on low-energy spin excitations in a novel quantum spin liquid candidate

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We plan to study the effect of magnetic field on the spin excitations in the newly discovered quantum spin liquid Na2BaCo(PO4)2. Our preliminary inelastic neutron scattering measurements on the powder sample reveals that the spin-excitation is continuum-type at base T (1K) without external field, with band-width in the order of 0.1 to 0.2 meV. With a large enough field above the critical value (Hc ~ 2T), the energy of the spin excitations is lifted. Most...

PERFECTA – A Superfluorinated Molecular Probe for MRI

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Magnetic resonance imaging (MRI) has had a transformative effect in modern medicine. A hot-spot imaging technique utilises another nucleus (such as 19F) to provide a second coloured layer, information which is independent to the anatomical details provided by the grey-scale proton NMR image. PERFECTA is a contrast agent which contains 36 equivalent 19F atoms and shows a single intense resonance peak. It is very stable and is easily synthesised using a one-step reaction. The hydrocarbon...

Using Neutron Tomography to study aqueous alteration processes on Mars

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Understanding the fluid pathways and timing(s) of fluid flow within Martian meteorites is critical to our understanding of the nature and origin of water at or near the red planet’s surface. Elucidating Mars’ aqueous past is critical to major questions on past or current habitable environments on Mars and the investigation of rocks and minerals formed through aqueous processes is a key driver for ESA and NASA robotic exploration missions. Neutron tomography’s sensitivity to hydrous...

Low-energy spin excitations in Ni over-doped NaFe0.7Ni0.3As

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The discovery of iron-based superconductors gives a new horizon to study unconventional superconductivity. Typically iron-based superconductors can be created by doping (i.e. replace Fe ions with) Co or Ni in some parent compounds such as NaFeAs. It is believed the magnetism in these materials is strongly coupled to superconductivity. One way to probe the magnetism in these materials is to observe the spin gap by inelastic neutron scattering. Our previous experiment shows no gap for...

Measurement of Reference Cross Sections of Li-ion Battery Materials via Energy Selective Neutron Imaging

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We would like to measure the reference cross sections of lithium-ion battery (LIB) materials. This is the first step of a project that will serve as a baseline to understand the transport limiting mechanisms that are on of the main reasons for capacity losses in LIBs. This technique has been used with 6-Li and 2-H isotopes, since they have a greater attenuation than their natural homologous. Here we would like to prove that energy selective...

uSR study of low temperature magnetism in Li NMC 811

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LiNi0.8Mn0.1Co0.1O2 (Li NMC 811) is a next generation Li ion battery cathode material. We are investigating the magnetic properties of Li NMC 811 to track the changes in local ordering of the magnetic ions and changes in oxidation state as a function of electrochemical cycling. Here we focus on pristine Li NMC 811 which contains S=1/2 Ni3+, S=1 Ni2+, S=3/2 Mn4+ and S=0 Co3+. In addition it is prone to off-stoichiometry and Li/Ni site disorder...

The structure of ruthenium pentacarbonyl: comparison to iron pentacarbonyl

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Of the metal carbonyls, iron pentacarbonyl, Fe(CO)5, is iconic: it was first reported in 1891 and was only the second metal carbonyl to be discovered, the structure is that of a trigonal bipyramid. There is no neutron diffraction data for Fe(CO)5. The only characterisation of the ruthenium congener of Fe(CO)5, Ru(CO)5, is a gas phase electron diffraction structure and infrared spectra in the C≡O stretch region. We propose to carry out the first structural and...

Structural distortions and partial order in the selenate and chromate analogues of mirabilite

The mineral mirabilite (di-sodium sulfate decahydrate) has been extensively studied by X-ray and neutron powder and single-crystal diffraction methods. The structure contains an interesting square ring of water molecules that is fully disordered at high temperatures, but which becomes partially ordered on cooling. One of the factors that appears to control this ordering process is a thermally-induced libration of the sulfate ions to which the square rings are hydrogen-bonded. In an effort to understand this...

Structural distortions and partial order in the selenate and chromate analogues of mirabilite

The mineral mirabilite (di-sodium sulfate decahydrate) has been extensively studied by X-ray and neutron powder and single-crystal diffraction methods. The structure contains an interesting square ring of water molecules that is fully disordered at high temperatures, but which becomes partially ordered on cooling. One of the factors that appears to control this ordering process is a thermally-induced libration of the sulfate ions to which the square rings are hydrogen-bonded. In an effort to understand this...

Magnetic excitations in AgCrSe2

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AgCrSe2 has emerged as a material of great interest due it its good thermoelectric performance. It also has an interesting cycloidal magnetic structure. While studying the thermoelectric parameters we have discovered that the previously published magnetic interactions are inconsistent with the magnetic structure. We now propose to study the magnetic excitations to higher energy than have previously been possible using MAPS which will allow us to resolve this.

Diffuse scattering investigation of out-of-equilibrium states in spin ice

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The spin ice material Dy2Ti2O7 is a frustrated material where the magnetic spins on a tetrahedra can only point into or out of the 111 crystallographic axis. Moreover, long range dipolar interactions competing with the local exchange means that 2 spins point into and 2 out of the 111 axis, and this state is degenerate, meaning there is a manifold of lowest energy states. Excitations out of this ground state make a 3 in, 1...

Determining the Crystal and Magnetic Structures of [Li(oxalate)]2[Co5(OH)8]

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Dense corrdination frameworks that contain inorganic centres connected into extended lattices by polyatomic anions often adopt highly anisotropic structures. Thus they often have strong magnetic interactions in only one or two dimensions and, in the latter case, can also be designed so they have strongly competing interaction that give rise to magnetic frustration. Recently discovered [Li(oxalate)]2[Co5(OH)8] appears likely to be one such two dimensional magnet. We will determine the structure of its antiferromagnetic state, which...

Hydration behaviour of uranyl chloride: from fundamental chemistry to environmental applications

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In water uranium exists almost exclusively as the uranyl ion [UO2]2+. In the presence of halides these can form complexes of the type [UO2(H2O)nClx]2-x, whose thermodynamics and structures in solution are not fully understood. This is important as high halide concentrations are expected to be found in spent nuclear fuels or under certain environmental conditions. In this work we propose to study the reaction of uranyl chloride [UO2(H2O)5][Cl]2 with LiCl under increasing halide concentrations to...

Investigating the composition of small Hellenistic silver coins using negative muons

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The quality of ancient silver coinage is often seen as a comment on the fiscal health of the issuing states. This is nowhere more apparent than with Roman coinages, which witnessed heavy debasements during the first three centuries of our era. Two processes are detectable: a reduction in the fineness of the alloys; and a reduction in weight standards. However, the hypothesis here is that the two processes are interlinked, and that the second is...

How do Surfactants Interact with Complex Monoclonal Antibodies at Oil/Water Interfaces?

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Heavily bio-engineered monoclonal antibodies (mAbs) are an increasingly important trend in the biopharmaceutical industry. However, these mAbs are often destabilised by the silicone oil found in pre-filled syringes, which are the preferred storage and application method for these drugs. This effect can be reduced by adding biologically safe surfactants to the formulation, but the mechanism by which this protects the mAb is currently not proven. This study will investigate the mAb-surfactant-silicone oil interaction, using several...

Title: IMAT commissioning : use of cold neutrons to discriminate minerals with similar density

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One of the major challenges of XCT is the lack of X-ray penetration in the dense mineral samples and the distinction of minerals with close atomic number Z. The lack of penetration results in beam hardening especially for minerals with densities higher than 3g/cm3. The utilisation of cold neutrons at IMAT with optimal neutron wavelengths (neutron energy dependant experiment) can be used to discriminate different iron ore oxides (hematite and magnetite) as well as 11...

Discriminating the conformation of G4 DNA by SANS.

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Guanine-­rich DNA sequences are prone to fold into stable helical four­-stranded structures called G­quadruplexes (G4). These systems have drawn the attention of a number of scientists in both basic and applied research fields, including structural biophysics, cancer biology, novel therapeutics through to nanotechnology. And most importantly, G4s have been proposed as selective and effective therapeutic anticancer targets. However, the intrinsic polymorphism of G4s makes very challenging the prediction of the architectural folds encoded in guanine-rich...

Registration Year

  • 2020
    2,109

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  • University of Strathclyde
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