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Showing 1 to 20 of 35 for “"Thermal Expansion Coefficients"”.
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Determination of the linear thermal expansion coefficients of the refractory carbides by X-ray diffraction
Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961
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Geopolymer-derived ceramics and composites
… tectosilicate material systems with tailorable thermal expansion was developed with the goal of designing new candidate materials for environmental barrier applications. The materials were studied with in situ high temperature synchrotron X-ray diffraction to explore the atomic mechanisms …
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Volume Changes Accompanying the Melt-Crystal Transition in Binary Borate Melts
… using x-ray unit cell densities and volume thermal expansion coefficients obtained by high-temperature x-ray diffraction analysis. Melt specific volumes had been previously determined.
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Steady state thermal stress analyses of two-dimensional and three-dimensional solid oxide fuel cells
… power. The present work characterizes the thermal stresses arising during the operation of planar solid oxide fuel cells which is a critical factor in the development of an efficient fuel cell. The thermal stresses are calculated from the temperature fields using ANSYS(TM). A sequentially …
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MICA optical : a low-cost, educational Michelson interferometer
… light wavelengths, coherence length, as well as thermal expansion coefficients with the addition of a few simple parts. The initial benchmarking, the design process, and the final manufacturing methods for this module are discussed. The result of this project is a modular kit that can accompany a …
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Thermal expansion of chemically modified mullite
… solid solutions in an effort to lower their thermal expansion coefficients. TiO₂, B₂O₃, CrPO₄, P2O₅, Ga₂O₃, Cr2O₃, and WO₃ and the half-breed SiO₂ compounds AlPas, BPO₄, GaPO₄, BAsO₄, AIAsO₄, GaAsO₄, and GeO₂ were chosen as the modifiers. The results indicate that, apart from TiO₂, none of …
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A method for the ply-level elastic characterization of composite materials using thick tubular angle-ply specimens
… a thick, laminated tube. The mechanical and thermal response of the tubes is modeled by a planar cylindrical elasticity solution. Properties are determined from surface strain measurements of a thick tube subject to axial, torsional, pressure, and thermal loads. All elastic properties …
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Moisture and stress effects on fretting between steel and polyimide coatings
… the annealing temperature due to the mismatch of thermal expansion coefficients between the polymer and the metal substrate. Calculated from elasticity theory, the normal stress dropped shortly after the start of the test, remained relatively constant, and increased toward the end. This variation …
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The response of polyhedra in close packed structures to temperature and pressure
… An analysis of apparent bulk moduli and linear thermal expansion coefficients calculated for the constituent polyhedra shows that the distortion of a material with a close packed structure is governed by its unoccupied as well as its occupied polyhedra. It also indicates that the rearrangement …
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A phenomenological treatment of thermal expansion in crystals of the lower symmetry classes and the crystal structures of CaCoSi₂O₆ and CaNiSi₂O₆
Thermal expansion in a crystal may be completely described from a phenomenological point of view by a second rank tensor whose elements are defined by λ<sub>ij</sub>=(∂l<sub>ij</sub>/∂T)<sub>σ</sub> Or ε<sub>ij</sub>=(∂e<sub>ij</sub>/∂T)<sub>σ</sub> Where the l<sub>ij</sub> and the e<sub>ij</sub> …
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The application of siloxane modified polyimides as high performance textile coatings
… which were subsequently evaluated regarding thermal stability, thermal behavior, and hydrophobicity. The polymer series included poly(imide siloxane)s which were prepared in two steps, the first involving the generation of soluble poly(amic acid} intermediates which were then cyclodehydrated …
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Thermoplastic composite consolidation
… model takes into account the mismatch of the thermal expansion coefficients and the crystallization shrinkage of the matrix. [O₁₀/90₆]<sub>T</sub> graphite-PEEK laminates were manufactured at different cooling rates to verify the model. The induced residual thermal defonnations were measured …
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Fractals in elastic-plastic transitions of random heterogeneous materials
… as elastic/plastic moduli, yield stresses or thermal expansion coefficients (or residual strains). The flow rule of each grain follows associated plasticity with increasing loads applied through either one of three macroscopically uniform boundary conditions admitted by the Hill-Mandel …
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Piezo-induced fatigue of solder joints
… the loading imposed by adherends with dissimilar thermal expansion coefficients under a temperature change. Using this concept, a double lap joint test specimen was developed to investigate the damage mechanisms in solder joints for electronic packaging applications under cyclic loading …
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Understanding and characterizing thermal transport in 2D van der Waals nanoelectronics
… and photonic applications. However, significant thermal challenges arise due to numerous van der Waals (vdW) interfaces limiting dissipation of heat generated in the device, induces significant temperature rise, and creates large thermal mismatch, resulting in the degradation of device …
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Theoretical study on toughening and design against fracture of functionally graded thermal barrier coatings
Functionally graded thermal barrier coatings (FG TBCs) are advanced multi-phase composites that are engineered to have a smooth spatial gradation of material constituents, which are normally ceramics and metal. The smooth gradation results in the reduction of thermal stresses, minimization or …
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II-VI Core-Shell Nanowires: Synthesis, Characterizations and Photovoltaic Applications
… ZnTe, which have close lattice parameters and thermal expansion coefficients, were chosen to fabricate nanowire solar cells. ZnTe and CdSe nanowires were first synthesized by thermal evaporation and the shells were subsequently deposited by PLD. ZnTe/CdSe nanowires represented an inhomogeneous …
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Selective epitaxial growth techniques to integrate high-quality germanium on silicon
… challenges, ranging from lattice mismatch, to thermal expansion coefficient mismatch, to non-planar morphological evolution. The lattice mismatch between Ge and Si often leads to a high density of threading dislocations. These dislocations, if not reduced, propagate through the subsequently …
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Coupled thermo-hydro-mechanical behavior of glacial tills in shallow geothermal systems
… applications whereby the ground is used as a thermal reservoir and soils are subjected to thermal gradients, such as shallow geothermal systems, motivated this study. The soil response under representative field conditions upon heating can affect the performance and overall operation of …
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High temperature ultrasonic gas flow sensor based on lead free piezoelectric material
… to reduce the negative effects of differences in thermal expansion coefficients between constituents of the transducer assembly.
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