2,484 research outputs found
Photograph of a bust of the author Tasma
No full textPhotograph of a bust of the author Tasma (Jessie Catherine Couvreur). Pencilled on verso of photo 'Tasma - enlargement of an original lent to H.M. Green? by Mrs Erdos, a neice of Tasma
Isogeometric analysis for multi-patch structured Kirchhoff–Love shells
No full textWe present an isogeometric method for Kirchhoff–Love shell analysis of shell structures with geometries composed of multiple patches and which possibly possess extraordinary vertices, i.e. vertices with a valency different to four. The proposed isogeometric shell discretisation is based on the one hand on the approximation of the mid-surface by a particular class of multi-patch surfaces, called analysis-suitable G1 (Collin et al., 2016), and on the other hand on the use of the globally C1-smooth isogeometric multi-patch spline space (Farahat et al., 2023). We use our developed technique within an isogeometric Kirchhoff–Love shell formulation (Kiendl et al., 2009) to study linear and non-linear shell problems on multi-patch structures. Thereby, the numerical results show the great potential of our method for efficient shell analysis of geometrically complex multi-patch structures which cannot be modelled without the use of extraordinary vertices.Funding Information: The authors wish to thank the anonymous reviewers for their comments that helped to improve the paper. A. Farahat and M. Kapl have been supported by the Austrian Science Fund (FWF) through the project P 33023-N. H.M. Verhelst is grateful for the funding from Delft University of Technology. J. Kiendl has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 864482). Additionally, the authors are grateful for the support from the developers of the Geometry + Simulation Modules, in particular from A. Mantzaflaris (Inria Sophia Antipolis-Méditerranée). Funding Information: The authors wish to thank the anonymous reviewers for their comments that helped to improve the paper. A. Farahat and M. Kapl have been supported by the Austrian Science Fund (FWF) through the project P 33023-N . H.M. Verhelst is grateful for the funding from Delft University of Technology . J. Kiendl has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 864482 ). Additionally, the authors are grateful for the support from the developers of the Geometry + Simulation Modules, in particular from A. Mantzaflaris (Inria Sophia Antipolis-Méditerranée).Numerical AnalysisShip Hydromechanics and Structure
Caracterização de ligas binárias nanoestruturadas dos sistemas Zn-Sb, Ge-Sb, Al-Sb e Co-Sb produzidas por síntese mecânica
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Ciência e Engenharia de Materiais.A síntese de materiais nanoestruturados bem como o estudo de suas propriedades físicas tem gerado enorme interesse do ponto de vista científico devido a uma série de novas aplicações tecnológicas que estes materiais possibilitam. Os trabalhos dessa tese de doutoramento produziram por Síntese Mecânica semicondutores nanoestruturados com potencial termoelétrico dos sistemas Zn-Sb e Co-Sb, ligas do sistema Al-Sb e soluções sólidas do sistema Ge-Sb. As propriedades físicas destes materiais em condições ambientes e, em alguns casos sob altas pressões, foram estudadas pelas seguintes técnicas experimentais: difração de raios x e refinamento estrutural usando o método de Rietveld, espectroscopia fotoacústica, calorimetria diferencial de varredura, fluorescência de raios x com energia dispersiva, espectroscopia Raman e absorção de raios x em altas pressões usando células de diamante. Os materiais nanoestruturados produzidos e apresentados nessa tese apresentaram diferenças nas suas propriedades físicas com relação àquelas das ligas de mesma composição química produzidas por outras técnicas, tanto em condições ambientes quanto em altas pressões. A influência da componente interfacial nas propriedades físicas dos materiais nanoestruturados foi avaliada e foram observadas importantes mudanças nas condutividades térmicas das ligas ZnSb, AlSb e CoSb3. No caso das soluções sólidas foi observado um aumento no limite de solubilidade. Nas medidas sob altas pressões, a componente interfacial mostrou grande influência nas transições de fase induzidas por pressão, especialmente aquelas do ZnSb. Synthesis and study of nanostructured materials have generated great interest by the scientific point of view due to several new possibilities of technological applications. In this Doctoral thesis, nanostructured semiconductors with thermoelectric potential of Zn-Sb and Co-Sb systems, alloys of Al-Sb system and solid solutions of Ge-Sb system were produced. The physical properties at ambient and, in some cases at high pressure conditions, were studied by the following experimental techniques: x-ray diffraction and structural refinements using Rietveld method, photoacoustic spectroscopy, differencial scanning calorimetry, energy dispersive x-ray fluorescence, Raman and absorption x-ray spectroscopies at high pressures with diamond anvil cell. The nanostructured materials produced and presented in this thesis showed differences in their physical properties as compared to alloys of equal chemical composition produced by other techniques, both at ambient and high-pressure contitions. The influence of interfacial component in the physical properties of the nanostructured materials was evaluated and it was observed important changes in the thermal conductivity of the ZnSb, AlSb and CoSb3 alloys. In the case of the solid solutions, it was observed an increasing in the limit of solubility. In the high pressure tests, the interfacial component showed huge influence on the pressure-induced phase transitions, especially for ZnSb
Samuel H.M. Byers; Poet; Author; Diplomat; Oskaloosa; Iowa; Mahaska County; Iowa
No full textThis is a photograph taken of Samuel H.M. Byers at the onset of the Civil War in 1861. Byers served in the Union Army during the Civil War and gained a great deal of inspiration for his poetic writing during the war. Byers's most famous work is a poem entitled "Sherman's March to the Sea" recapping events that took place during this famous piece of American history. Byers is also credited with writing the state song of Iowa, played to the melody of "O, Christmas Tree". After gaining fame and fortune from his writing, Byers pursued a career in diplomacy, serving in the U.S. Consulate in Switzerland and Italy. Byers then came back to the U.S., living out the remainder of his days in Los Angeles, California. Byers died in 1933, at the age 95
Formation energy and migration barrier of a Ge vacancy from ab initio studies
No full textHere we present local density functional calculations of the formation and migration energies of a vacancy in large Ge supercells and hydrogen-terminated Ge clusters. Migration barriers for neutral (V0), negatively charged (V-) and double negatively charged (V=) vacancies were calculated by using symmetry-constrained atomic relaxations, as well as a nudged elastic band scheme. The formation energy of the neutral vacancy is estimated at 2.6 eV, whereas 0.4, 0.1 and 0.04 eV are obtained for migration barriers of V0, V- and V=, respectively. These figures account well for the formation kinetics of vacancy-impurity complexes in Ge at cryogenic temperatures, and are also in line with measured self-diffusion activation barriers obtained at elevated temperatures</p
L'Image Du Buddha Dans L'Art Lao
No full textText and photos of Buddha images in LaosL'Image Du Buddha Dans L'Art Lao. Vientiane: H.M. Demain, 197
Crystal structures of synthetic Ge-leucite analogues.
No full textCrystal structures of synthetic Ge-leucite analogues.
A.M.T.Bell (Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, S1 1WB, UK).
The crystal structure of the anhydrous synthetic analogue of the silicate framework mineral leucite (KAlSi2O6) is I41/a tetragonal [1], K cations sit in extraframework channels in the crystal structure. Replacement of K by Rb gives a similar I41/a tetragonal structure for RbAlSi2O6 [2]. However, replacement of K by Cs gives an Ia-3d cubic structure for CsAlSi2O6 [3]. This cubic structure has the same topology as the tetragonal leucite structures, in all these structures silicon and aluminium cations are disordered over tetrahedrally coordinated sites (T-sites). Many more leucite analogue crystal structures are known with general formulae A2BSi5O12 and ACSi2O6, where A is a monovalent extraframework cation, B is a divalent cation and C is a trivalent cation [4].
However, it is possible to make leucite analogues where Si is replaced by Ge in germanate framework crystal structures. Synthetic Ge-leucite analogues, with the general formulae AAlGe2O6 (A = K, Rb, Cs), have been studied by X-ray powder diffraction and Rietveld refinement [5]. Crystal structures are reported for these three Ge-leucite analogues [6], the A = K and Rb structures have not yet been published, the A = Cs structure is similar to a previously published structure [7].
AAlGe2O6 is isostructural with I41/a tetragonal KAlSi2O6. However, RbAlGe2O6 and CsAlGe2O6 are not isostructural with their silicate leucite analogues. Both have the I-43d cubic structure which is isostructural with that for KBSi2O6 [8]
[1] Mazzi F., Galli E., Gottardi G. Am. Mineral. 1976;61:108-115.
[2] Palmer D.C., Dove M.T., Ibberson R.M., et al. Am. Mineral. 1997;82:16-29.
[3] Beger R.M. Z. Krist. 1969;129:280-302.
[4] Bell A.M.T. submitted to Crystallography Reviews, 2023.
[5] Rietveld H.M. J. Appl. Cryst. 1969;2:65-71.
[6] Bell A.M.T. Powder Diffraction (in preparation) 2024.
[7] Tripathi A., Parise J.B. Micro. Meso. Mat. 2002;52:65–78.
[8] Millini R., Montanari L., Bellussi G. Microporous Mat. 1993;1:9-15
Thermally-enhanced oil recovery from stranded fields: Synergy potential for geothermal and oil exploitation
No full textAccepted author manuscriptReservoir EngineeringApplied Geolog
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