Browsing by Author "Karatchevtseva, I"
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- Item3d transition metal complexes with a julolidine–quinoline based ligand: structures, spectroscopy and optical properties(Royal Society of Chemistry, 2015-12-07) Fanna, DJ; Zhang, YJ; Li, L; Karatchevtseva, I; Shepherd, ND; Azim, A; Price, JR; Aldrich-Wright, JR; Reynolds, JK; Li, FA Schiff base type ligand with the combination of the julolidine and the quinoline groups has been reported as a potential chemosensor in detecting the cobalt(II) ion among other heavy and transition metal ions in solution. However, no crystal structure of such a ligand with any metal ions has been reported. In this work, its complexation with 3d transition metal ions (Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) has been investigated with five new complexes being synthesised, and spectroscopically and structurally characterised. [Mn2L2(CH3OH)2(CH3COO)2]•CH3OH (1) {HL (C22H21N3O) = ((E)-9-((quinolin-8-ylimino)methyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-8-ol)} shows a dinuclear structure with two Mn : L : acetate (1 : 1 : 1) units bridged by two methanol molecules. [CoL2(NO3)]•CH3OH•H2O (2) and [NiL2]•H2O (3) exhibit mononuclear structures with a Co : L or Ni : L ratio of 1 : 2. [CuL(CH3COO)]•1/3CH3OH (4) demonstrates a mononuclear structure and the Cu ion has a square planar coordination polyhedron with a L ligand and a highly non-symmetrical acetate anion. [Zn2L2(CH3COO)2]•CH3OH (5) has two types of dinuclear units, both with two ZnL units bridged by two acetate anions but in three different bridging coordination modes. Their vibrational modes, absorption and photoluminescence properties have also been investigated. © 2016 The Partner Organisations
- ItemAqueous chemical synthesis of Ln2Sn2O7 pyrochlore-structured ceramics(John Wiley and Sons, 2013-06-03) Kong, L; Karatchevtseva, I; Blackford, MG; Scales, N; Triani, GPyrochlore-structured lanthanide stannate ceramic (Ln2Sn2O7) has been synthesized via a new complex precipitation method. A suite of characterization techniques, including FTIR, Raman, X-ray, and electron diffraction as well as nitrogen sorption were employed to investigate the structural evolution of the synthesized and calcined powder. Raman, XRD, and selected area electron diffraction results confirm the presence of the pyrochlore structure after calcination of the powder above 1200°C. TEM imaging shows fine crystallites gradually increased in size from approximately 100 nm to about 500 nm with higher calcination temperatures. Grain growth and powder densification upon increasing the calcination temperature was confirmed by nitrogen sorption results. This aqueous synthetic method provides a simple pathway for the preparation of homogeneous lanthanide stannate ceramics. © 2013, The American Ceramic Society.
- ItemBeneficial effect of iron oxide/hydroxide minerals on sulfuric acid baking and leaching of monazite(Elsevier B. V., 2022-05) Demol, J; Ho, E; Soldenhoff, KH; Karatchevtseva, I; Senanayake, GThe sulfuric acid bake/leach process is an established industrial process for the extraction of rare earths from hard-rock monazite ores/concentrates. The chemical reactions in the monazite acid bake can be strongly influenced by the gangue mineralogy of the ore/concentrate. In this work, the beneficial effect of three iron oxide/hydroxide minerals, namely hematite, goethite and magnetite, added to high grade monazite concentrate in the acid bake (temperature range of 200–800°) and leach process was investigated to understand the role of iron gangue. Baked solids and leach residues were characterised by elemental analyses, XRD, SEM-EDS and FT-IR. It was found that the addition of iron minerals to the monazite acid bake had a significant impact on bake chemistry, acting to significantly increase the leaching of both the rare earth elements and thorium, compared to monazite alone, mainly for temperatures above 300 °C. The increased dissolution of rare earth elements and thorium was attributed to the formation of an amorphous and insoluble iron sulfate-polyphosphate type phase in preference to insoluble rare earth and thorium containing polyphosphates identified during acid baking of monazite alone. After baking at 650 °C, the iron sulfate-polyphosphate type phase was altered to a more soluble form, leading to an increase in dissolution of iron, phosphorus and thorium. Acid baking at 800 °C led to the formation of FePO4, Fe2O3, CePO4 (monazite) and in some cases CeO2, causing a decrease in leaching of rare earths and thorium, and either an increase or a decrease in leaching of iron and phosphorus depending on the formation of FePO4 versus Fe2O3. Crown Copyright © 2022 Published by Elsevier B. V.
- ItemCoordination polymers of perylenetetracarboxylate with Cs(I) ions: 3D structures with 2D inorganic layers or triple coordination nets(Elsevier B. V., 2023-02) Nguyen, TH; Karatchevtseva, I; Bhadbhade, MM; Zhang, YJThe self-assembly of perylenetetracarboxylate (ptc) with Cs(I) ions at ambient temperature has been investigated with two coordination polymers being synthesized and structurally characterized. The diffusion of ethanol into a Cs-ptc solution led to the formation of compound 1 [(Cs4(ptc)(H2O)5·nH2O] displaying a compact three-dimensional (3D) structure constructed with 2D undulating layers of Cs polyhedra linked by ptc ligands in two types coordination modes. Extensive π···π interactions among stacking ptc ligands formed large hydrophobic organic channels between the inorganic layers. The addition of ethylenediamine (ED) to the reaction system afforded the formation of compound 2 [(H2ED)5Cs2(ptc)3(H2O)10] showing triple 2D coordination nets with protonated ethylene diammonium cations hydrogen-bonded to both non-bonded carboxyl oxygen and coordinated water molecules. The triple 2D nets are further linked via hydrogen bonding to form a 3D structure. The optical absorption, band gap analysis, vibrational modes and thermal stability of compound 1 were also investigated. Overall, the structural diversity was achieved in the studied self-assembly system at ambient temperature through varying Cs to ptc ratios by introducing ethylene diammonium as a non-metal cation. © 2023 Elsevier B.V.
- ItemCorrosion performance of Ni-16%wt.Mo-X%wt.SiC alloys in FLiNaK molten salt(Elsevier, 2018-10-01) Yang, C; Muránsky, O; Zhu, HL; Karatchevtseva, I; Holmes, R; Avdeev, M; Jia, YY; Huang, HF; Zhou, XTThe corrosion performance of Ni-16%wt.Mo-X%wt.SiC (X = 0.5, 1.5, 2.0, 2.5 and 3.0) alloys prepared via mechanical alloying followed by consolidation using spark plasma sintering (SPS) from pure Ni, Mo and SiC powders is investigated. Corrosion testing at 650 °C/200 h in FLiNaK molten salt showed that increasing the volume fraction of SiC in the initial Ni-Mo-SiC powder mixture leads to formation of large amount of Mo2C precipitates, which readily dissolve into FLiNaK molten salt. Hence, only the corrosion resistance of NiMo-SiC alloys with a low SiC content (<2 wt.%) is comparable to that of Hastelloy-N® alloy. © 2018 Elsevier Ltd. All rights reserved.
- ItemCorrosion performance of Ni-based structural alloys for applications in molten-salt based energy systems: experiment & numerical validation(Elsevier, 2021-09) Lee, M; Muránsky, O; Karatchevtseva, I; Huang, HF; Laws, KJThe molten salt corrosion performance of a Y2O3-strengthened Ni-Cr alloy (MA754®) designed for high temperature applications (> 750 °C) was compared to purpose-designed Ni-Mo-Cr molten-salt resistant alloys (GH3535, HASTELLOY-N®). The significant material mass loss of MA754® alloy is attributed to its higher Cr-content. However, Y2O3 dispersoids are shown to play only a minor role in the corrosion performance of this oxide-dispersion-strengthened (ODS) alloy. The current result, thus, points to the possibility for the development of low Cr-content ODS alloys that combines the high-temperature properties of ODS MA754® alloy with good molten salt corrosion resistance of well-established GH3535 and HASTELLOY-N® alloys. Crown Copyright © 2021 Published by Elsevier Ltd
- ItemCrystal chemistry and structures of uranium-doped gadolinium zirconates(Elsevier, 2013-07-01) Gregg, DJ; Zhang, YJ; Zhang, ZM; Karatchevtseva, I; Blackford, MG; Triani, G; Lumpkin, GRA series of uranium-containing gadolinium zirconate samples have been fabricated at 1450 °C in oxidizing, inert and reducing atmospheres. X-ray diffraction, Raman spectroscopy and transmission electron microscopy have been utilized to confirm adoption of pyrochlore or defect fluorite structures. X-ray diffraction allowed determination of the bulk averaged structure while Raman spectroscopy and transmission electron microscopy were used to determine ordering at the microdomain scale. Diffuse reflectance, X-ray absorption near edge structure and X-ray photoelectron spectroscopies indicated a predominantly U6+ oxidation state for all the air-sintered samples, even when Ca2+ or A-site vacancies were incorporated to charge balance for U4+, a mixed U5+/U6+ oxidation state was found for samples sintered in argon, while a mixed U4+/U5+ oxidation state occurred for sintering under N2–3.5%H2. This demonstrates a degree of uranium oxidation state control through sintering conditions, and the potential of using gadolinium zirconates as host materials for uranium in nuclear waste applications.© 2013, Elsevier B.V.
- ItemCrystallization of TiO2 powders and thin films prepared from modified titanium alkoxide precursors(Wiley-Blackwell, 2008-06) Karatchevtseva, I; Cassidy, DJ; Zhang, Z; Triani, G; Finnie, KS; Cram, SL; Barbé, CJThe modification of titanium alkoxides by chemical reactions with ligands yields complexes or molecular clusters that are substantially different from those of the parent alkoxides. In this study, we investigate the structural evolution of powders and thin films prepared from two titanium oxo-alkoxyacylate clusters with different oxo-core structures [Ti6(μ3-O)2(μ2-O)2](CH3COO)8(μ2-OiPr)2(OiPr)6 and [Ti6(μ3-O)6](μ-RCOO)6(OiPr)6 ([6,4] and [6,6], respectively) as a function of annealing temperature. The structural evolution of powders and thin films prepared from the corresponding parent alkoxide Ti(OiPr)4 (TiP) were also investigated for comparison. In all powders, the amorphous-to-anatase transformation occurred upon heating to 400°C. In sharp contrast, the anatase-to-rutile transformation of the powder prepared from the [6,6] cluster was significantly inhibited compared with the conventionally derived powder, with no rutile being detected even after annealing at 800°C for 1 h. This was attributed to the small crystallite size in the [6,6]-derived powder, which is lower than the critical size previously reported for the anatase-to-rutile transformation in similar sol–gel-derived materials. In thin films, the amorphous-to-anatase phase transition also occurred at temperatures as low as 400°C for coatings deposited from conventional TiP precursor and [6,4] cluster solutions. However, in contrast to the corresponding powders no rutile nucleation occurred even at 800°C in either film. © 2008, Wiley-Blackwell.
- ItemCu (II) ion directed self-assembly of a Y8/Cu6 heterometallic coordination cage via an Y (III) metalloligand(Elsevier, 2019-01-01) Zhang, YJ; Harman, DG; Avdeev, M; Karatchevtseva, IA non-centrosymmetric yttrium [Y(III)] metalloligand, [Y(H3L)(NO3)]·2NO3·THF (1) {tris{[2-{(imidazole)methylidene}amino]-ethyl}amine = H3L}, was synthesized and subsequently used in a Cu(II) directed self-assembly process to form a Y8/Cu6- type heterometallic coordination cage [Cu6Y8L8(NO3)5(H2O)3]·7NO3·21H2O (2). The eight corners of the distorted cubic cage are defined by eight Y(III) ions while Cu(II) ions occupy the centers of six faces with two opposite Cu(II) ions considerably outside the faces. The asymmetric Y(III) metal centres due to the extra coordination of either water molecules or nitrate anions induce chirality in the cage, with equal numbers of both enantiomers present in the solid state. The cage formation in both solution and in the solid state was demonstrated by ESI-MS and single crystal X-ray diffraction. Magnetic property measurements indicate that cage 2 remains paramagnetic down to 2 K. In addition, vibrational modes, electronic structure and thermal stability of the coordination cage 2 have been further investigated and reported. Crown Copyright © 2018 Published by Elsevier B.V.
- ItemDeuterium retention and near-surface modification of ion-irradiated diamond exposed to fusion-relevant plasma(IOP Science, 2014-04-01) Deslandes, A; Guenette, MC; Corr, CS; Karatchevtseva, I; Thomsen, L; Lumpkin, GR; Riley, DPChemical vapour deposited diamond was irradiated with 5 MeV carbon ions to simulate the damage caused by collision cascades from neutron irradiation in a fusion environment. Ion-irradiated samples were then exposed to a deuterium plasma in MAGPIE with ion flux of ~1.3 × 1021 ions m−2 s−1. Raman and near edge x-ray absorption fine structure (NEXAFS) spectroscopy were used to characterize the degree of disorder and sp2-bonding induced by the ion irradiation. The signals of sp2-bonded and disordered carbon were observed to decrease after exposure to the deuterium plasma, although sharp Raman peaks indicative of vacancy and interstitial defects induced by the MeV ions were less affected. Recovery of a diamond-like surface after plasma exposure was evident in the NEXAFS spectra. Elastic recoil detection analysis showed that the ion-damaged diamond retained more deuterium than diamond exposed only to deuterium plasma. For the case of unirradiated samples, diamond retained more deuterium than graphite. However, for the case of the ion-irradiated samples, diamond exhibited less deuterium retention than graphite. © 2014, IAEA Vienna.
- ItemDiamond structure recovery during ion irradiation at elevated temperatures(Elsevier, 2015-12-15) Deslandes, A; Guenette, MC; Belay, K; Elliman, RG; Karatchevtseva, I; Thomsen, L; Riley, DP; Lumpkin, GRCVD diamond is irradiated by 5 MeV carbon ions, with each sample held at a different temperature (300–873 K) during irradiations. The defect structures resulting from the irradiations are evident as vacancy, interstitial and amorphous carbon signals in Raman spectra. The observed variation of the full width at half maximum (FWHM) and peak position of the diamond peak suggests that disorder in the diamond lattice is reduced for high temperature irradiations. The dumbbell interstitial signal is reduced for irradiations at 873 K, which suggests this defect is unstable at these temperatures and that interstitials have migrated to crystal surfaces. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy results indicate that damage to the diamond structure at the surface has occurred for room temperature irradiations, however, this structure is at least partially recovered for irradiations performed at 473 K and above. The results suggest that, in a high temperature irradiation environment such as a nuclear fusion device, in situ annealing of radiation-created defects can maintain the diamond structure and prolong the lifetime of diamond components. © 2015 Elsevier B.V.
- ItemDioxo-vanadium(V), oxo-rhenium(V) and dioxo-uranium(VI) complexes with a tridentate Schiff base ligand(Royal Society of Chemistry, 2016-08-03) Zhang, YJ; Fanna, DJ; Shepherd, ND; Karatchevtseva, I; Lu, KT; Kong, L; Price, JRThe complexation of a julolidine–quinoline based tridentate ligand with three oxo-metal ions, dioxo-vanadium(V), oxo-rhenium(V) and dioxo-uranium(VI), has been investigated with four new complexes being synthesised and structurally characterised. (VO2L)·2/3H2O (1) {HL (C22H21N3O) = ((E)-9-((quinolin-8-ylimino)methyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-8-ol)} has a VO2L neutral mononuclear structure with a five-fold coordinated vanadium metal centre in a distorted trigonal bipyramidal geometry. (ReOL2)2(ReCl6)·7DMF (2) [DMF = dimethylformamide] exhibits a mixed valent rhenium complex with a (ReOL2)+ cationic unit in a distorted octahedral metal coordination geometry, charge balanced with (ReCl6)2− anions. [(UO2)L(H2O)2]2·2(NO3)·HL·4H2O (3) and [(UO2)L(CH3OH)2](NO3)·CH3OH (4) both have (UO2L)+ cationic mononuclear structures with either coordinated water or methanol molecules in pentagonal bipyramidal coordination geometries for the uranium metal centres. Intra-/intermolecular interactions including hydrogen bonding and π–π interactions are common and have been discussed. In addition, optical absorption and photoluminescence properties have been investigated. © 2016 The Royal Society of Chemistry
- ItemDysprosium complexes with mono-/di-carboxylate ligands—from simple dimers to 2D and 3D frameworks(Elsevier, 2014-11-01) Zhang, YJ; Bhadbhade, MM; Scales, N; Karatchevtseva, I; Price, JR; Lu, KT; Lumpkin, GRFour dysprosium (Dy) single carboxylates, a formate, a propionate, a butyrate and an oxalate have been synthesized and structurally characterized. The structure of Dy(HCO2)3 (1) contains nine-fold coordinated Dy polyhedra in perfect tricapped trigonal prisms. They are linked through trigonal O atoms forming 1D pillars which are further linked together through tricapped O atoms into a 3D pillared metal organic framework. The network structure is stable up to 360 °C. The structure of [Dy2(C2O4)3(H2O)6]·2.5H2O (2) contains nine-fold coordinated Dy polyhedra linking together through μ2-bridging oxalate anions into a 2D hexagonal layered structure. Both [Dy2(Pr)6(H2O)4]·(HPr)0.5 (3) [Pr=(C2H5CO2)−1] and [Dy2(Bu)6(H2O)4] (4) [Bu=(C3H7CO2)−1] have similar di-nuclear structures. The Raman vibration modes of the complexes have been investigated. © 2016 Elsevier B.V.
- ItemEffect of annealing upon retention of He and H in irradiated SiC(Trans Tech Publications, 2017) Ionescu, M; Deslandes, A; Holmes, R; Guenette, MC; Karatchevtseva, I; Lumpkin, GRSilicon carbide (3C-β SiC) samples were irradiated with He ions of energy up to 30 keV and a fluence up to 1016/cm2, to produce damage in the near-surface region. A duplicate set of He ion irradiated SiC samples, as well as undamaged SiC, were also irradiated with H2+ ions of energy up to 20 keV and a similar fluence, to study the interaction of H species with pristine SiC and with He radiation-damaged SiC. Samples were annealed in steps of 200 K, from 473 K to 1273 K, and the retention of H and He were measured using elastic recoil detection analysis with 7.8 MeV C3+ ions, after each anneal step. Modification to the surface following irradiation is observed via Raman spectroscopy, which exhibits development of damage states such as disordered carbon and Si-Si peaks. Only minor changes in the H and He profiles were observed up to 1073 K, however after the 1273 K anneal the H and He profiles changed considerably, with a marked difference between samples irradiated only with He and those irradiated with He and H. © 2025 Trans Tech Publications Ltd
- ItemEffects of selected process parameters on the morphology of poly(ethylene terephthalate) preforms and bottles(Wiley-Blackwell, 2007-10-05) Hanley, TL; Sutton, D; Karatchevtseva, I; Cookson, DJ; Burford, RP; Knott, RBSmall-angle X-ray scattering (SAXS) studies and polarized optical microscopy were undertaken to explore possible morphological explanations for the poor mechanical strength in the petaloid bases of poly(ethylene terephthalate) bottles. With a standard commercial production line, one set of injection-molded preforms was over-packed by 1.1 wt % to investigate the effect on the molecular morphology with respect to a set of control samples. Both sets of preforms showed highly crystalline and oriented areas corresponding to the injection gate region. The main body of the control preform was amorphous, and although the overpacked preform was essentially amorphous, there was some evidence for weak crystallinity. The SAXS patterns of the bottle petaloid base blown from the corresponding preforms produced similar SAXS patterns for overpacked and control bottle bases, indicating that the commercial process is robust at least to this degree of overpacking. Optical microscopy showed detailed crystalline features around the gate region and thin crystalline layers sandwiched between a quenched skin layer in direct contact with the cold mold walls and the main flow of material into the mold. © 2007, Wiley-Blackwell.
- ItemGd2Zr2O7 and Nd2Zr2O7 pyrochlore prepared by aqueous chemical synthesis(Elsevier, 2013-12-01) Kong, L; Karatchevtseva, I; Gregg, DJ; Blackford, MG; Holmes, R; Triani, GPyrochlore structured Gd2Zr2O7 and Nd2Zr2O7 are produced via complex precipitation processing. A suite of characterization techniques, including FTIR, Raman, X-ray and electron diffraction, TEM, SEM as well as nitrogen sorption are employed to investigate the structural and grain size evolution of the synthesized and calcined powder. Results show that Gd2Zr2O7 with the pyrochlore structure are produced after calcination at 1400 °C for 12 h while Nd2Zr2O7 has already formed the pyrochlore structure at 1200 °C. This method allows the formation of dense materials at relatively low temperature, with bulk densities over 92% of the theoretical values achieved after sintering at 1400 °C for 50 h. This unique aqueous synthetic method provides a simple pathway to produce pyrochlore lanthanide zirconate without using either organic solvent and/or mechanical milling procedures, making the synthesis protocol an attractive potential scale-up production of highly refractory ceramics. © 2013, Elsevier Ltd.
- ItemHydrothermal synthesis, structures and properties of two uranyl oxide hydroxyl hydrate phases with Co(II) or Ni(II) ions(Royal Society of Chemistry., 2016-04-11) Zhang, YJ; Čejka, J; Lumpkin, GR; Tran, TT; Aharonovich, I; Karatchevtseva, I; Price, JR; Scales, N; Lu, KTTwo new iso-structured uranyl oxide hydroxyl hydrate (UOH) phases with the incorporation of cobalt(II) or nickel(II) ions have been synthesised under hydrothermal conditions and structurally characterised. Both K4Co(OH)3(H2O)9[(UO2)12(O)7(OH)13] (1) and K4Ni(OH)3(H2O)9[(UO2)12(O)7(OH)13] (2) have two-dimensional (2D) polymeric uranyl oxohydroxyl layers with either potassium and hydroxyl cobalt(II) (1) or potassium and hydroxyl nickel(II) (2) ions between layers via uranyl–cation interactions. This work highlights the feasibility of making new UOH phases via a hydrothermal route at relatively higher solution pHs. It also demonstrates that other transition metal ions which are readily available in the environment may also be incorporated into such UOH phases during the natural weathering of uraninite as well as during the storage and disposal of spent nuclear fuels. © 2016 The Royal Society of Chemistry
- ItemImmobilization of iodine via copper iodide(Elsevier, 2018-07) Vance, ER; Grant, C; Karatchevtseva, I; Aly, Z; Stopic, A; Harrison, JJ; Thorogood, GJ; Wong, HKY; Gregg, DJCuI is a candidate wasteform for the immobilization of the fission product 129I. CuI can be made simply by the addition of CuCl to an I− bearing solution such that exchange of Cl− with I− takes place. The CuI material can then be consolidated into a wasteform by sintering at approximately 550 °C in argon or by hot isostatically pressing at 550 °C with 100 MPa of pressure. A waste loading of greater than 60 wt.% is achievable with good water leach resistance, in keeping with the low solubility product of CuI. However, like the well known wasteform candidate AgI, CuI decomposes in water containing metallic Fe. To compensate this deficiency, the sintered CuI wasteform can be further protected by surrounding it by Sn powder and HIPing at the low temperature of 200 °C. © 2018 Elsevier B.V
- ItemThe incorporation of Li2SO4 into barium borosilicate glass for nuclear waste immobilisation(Elsevier, 2022-03-15) Farzana, R; Dayal, P; Karatchevtseva, I; Aly, Z; Gregg, DJThis study has systematically investigated the effect of Li2SO4 addition (2.75 −16.5 wt%) in barium borosilicate glass, to provide a pathway to optimise the glass composition and maximise sulphate incorporation. The work also provides a mechanistic understanding as to how SO42- is incorporated within the glass structure. The highest sulphate incorporation of 2.78 wt% SO3 (from 11 wt% Li2SO4 addition) was achieved without crystallisation following melting at 1200 °C. Sulphate incorporation in glass was confirmed by XRF, ICP, EDS and Raman analysis. Addition of Li2SO4 along with sodium and barium oxides improved the sulphate incorporation by mixed alkali network depolymerisation and the larger Ba cations helped to create sufficient space within the boron-silicate network to incorporate sulphate ions into the glass. An immiscible sulphate layer rich in BaSO4 and Na2SO4 formed on top of the glass at lower temperature (800–1100 °C) and subsequent diffusion of Na, Ba oxides and sulphur from this layer increased with increasing time and temperature to form a sulphate incorporated amorphous glass. Addition of Na2O played an important role to improve sulphate incorporation in the glass, as well as formation of an immiscible layer on top of the glass however, the formation of Na2SO4 lowered the sulphur incorporation rate at high temperature compared to BaSO4. Increasing the Li2SO4 content in the glass decreased the glass transition temperature. Aqueous durability testing using the standard PCT tests indicated the glass had satisfactory aqueous durability compared to benchmark environmental assessment glass. This study provides opportunities to convert Li+ and SO42- rich nuclear wastes into appropriate glass wasteforms. © 2021 Elsevier B.V.
- ItemIndefinite media based on wire array metamaterials for the THz and Mid-IR(John Wiley and Sons, 2013-11-08) Naman, OT; New-Tolley, MR; Lwin, R; Tuniz, A; Al-Janabi, AH; Karatchevtseva, I; Fleming, SC; Kuhlmey, BT; Argyros, AFibre drawing is used to fabricate indefinite media based on wire array metamaterials. Fibres containing arrays of indium wires embedded in polymer are drawn using an optical fibre draw tower, a technique that is intrinsically scalable to larger-volume fabrication. During drawing, the surface tension of the liquid indium can result in fluctuations to the wire diameter through the Plateau–Rayleigh instability. This is investigated and minimised through a modification of the draw process to achieve wire diameters as low as 1 micrometer. Such wire array fibres are assembled and characterised as electric metamaterials through the resulting high-pass filtering behaviour. By controlling the draw ratio, the fibre drawing technique is shown to produce electric metamaterials over a wide range of frequencies, from the THz through to the edge of the mid-IR.© 2013 Wiley-Vch Verlag.
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