Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 69 for “"Phase boundaries"”.
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Characterization of Internal Boundary Layer Capacitors Based Upon Barium-Titanate and Strontium-Titanate
… boundary conditions existing at grain and phase boundaries. The dielectric properties of internal boundary layer capacitor are directly related to their microstructure, in which semiconducting grains are surrounded by continuously connected thin insulating boundaries. Heterogeneous …
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CERAMIC MATERIALS USED IN SOLID-OXIDE FUEL CELLS
… high efficiency and low emission. . The triple-phase-boundaries (TPBs), where cathode and electrolyte make contact with gas phase, are considered to be the active sites for oxygen reduction reactions. The microstructure and chemical properties of TPBs appear to play a significant role in the …
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Experimental study of tricritical phenomena in the metamagnet ferrous chloride (FeCl₂)
… found to show discontineous changes at the mixed-phase boundaries. A theory which explains the step discontinuity in heat capacity CH 1s presented. The a strong light scattering in the mixed-phase region has been used to determine the mixed-phase boundaries and result in the tricritical exponent …
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Transport of Molecular Cargoes By Coordination Cages Between Immiscible Liquid Phases
… these systems, coordination cages cross liquid phase boundaries upon exposing to heat stimuli or diffuse within aqueous membrane layers to promote the passage of materials. The first system employs a thermoresponsive cage, FeII4L4, to transport encapsulated cargo across multiple phase …
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The thermodynamics of the ZnO-Fe₂O₃-Fe₃O₄ system
… was to (1) experimentally locate certain phase boundaries in three isothermal sections of the zinc oxide - ferric oxide - magnetite phase diagram, (2) to experimentally determine some of the thermodynamic properties of the zinc oxide - ferric oxide - magnetite system, (3) to use the …
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Investigation of van der Waals ferroelectric CuInP2S6 by scanning probe microscopy
… (Cu0.2In1.26P2S6), which exhibits a nanoscale phase separation. The paraelectric In4/3P2S6 (IPS) phase exhibits higher friction than the ferroelectric CIPS phase, while phase boundaries display the lowest friction. We also observe a thickness-dependent friction behaviour in Cu0.2In1.26P2S6. The …
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A mathematical model of wheelchair racing
… an arbitrary number of consecutive ballistic phases such that segment positions are continuous at phase boundaries. Each phase is mathematically a second-order, nonlinear ordinary boundary value problem (BVP). Numerical methods are used to solve the BVPs independently, resulting in velocity …
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Phenomenology And Experimental Observations In High Temperature Ternary Interdiffusion
… obtained from selected semi-infinite, single-phase diffusion couple experiments in the Cu-Ni-Zn, Fe-Ni-Al, and Ni-Cr-Al systems. These couples exhibit features such as uphill diffusion and zero flux planes. The interdiffusion coefficients from the new technique along with coefficients reported …
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Atomistic simulation of defect structure in Nb-Ti-Al
… of room temperature ductility. However, a B2 phase in the ternary Nb-Ti-Al system has been discovered which exhibits considerable ductility at room temperature. Three different alloy compositions which exhibit this ductile phase were examined by computer simulation using the Embedded Atom …
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Pressure-Temperature Phase Diagram of LiAlH4
… of the monoclinic alpha-LiAlH4 to delta-LiAlH4 phase at ~3.25 GPa. As the temperature is increased to ~100°C both the alpha and delta phases transform to beta-LiAlH4 and remain stable up to 5.5 GPa. At temperatures greater than 300°C a new gamma-LiAlH4 phase forms. The data obtained in this …
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On the Modeling and Analysis of Machining Performance in Microendmilling
… process in the micro-endmilling of both single phase and multi-phase workpiece materials was also examined. 508 micron diameter endmills with edge radii of 2 and 5 microns were used to machine slots in ferrite, pearlite and two ductile iron materials at feedrates ranging from 0.25 to 3.0 …
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Developing transition metal dichalcogenide alloys for applications to integrated photonics
… of transition metal dichalcogenides (TMDs) as phase-change materials for photonics integrated circuits (PIC). We measure the near-infrared (NIR) optical properties of bulk crystal telluride TMDs and sulfide TMDs. We find that telluride TMDs have large optical density and large optical contrast, …
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Novel phase and phase transition behavior of a superionic conductor observed on the nanoscale
… the ionic structure, vacancy ordering, phase transitions, and ion transport in a prototypical fast-ion conductor, copper selenide. Major objectives of my work were to elucidate i) the nature of the structural phase transition by which copper selenide becomes a superionic phase and ii) …
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On-line Final Quality Prediction for Multiphase Batch Processes with Uneven Durations
… durations, multicollinearity of variables, multiphase behaviour, and lack of availability for real-time quality sensors. Off-line quality control strategies are insufficient since no timely corrective interventions can be implemented. Data-driven techniques based on latent methods such as …
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Controlling crystallization via interfacial engineering : patterning, fouling-inhibition, and nutrient recovery
… propensity of many forms of crystals to form at phase boundaries. Control of crystallization on solid substrates is accomplished by modification of the surface morphology, length scale of surface features, surface chemistry, and surface energy. In this thesis I demonstrate that interfacial …
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The one-dimensional spin-1/2 ANNNI model in non-commuting magnetic fields
… a starting point we obtained an estimate of the phase diagram of the model by treating the spins as classical vectors. This was followed by an investigation of the zero temperature ground state of the one-dimensional spin-1/2 ANNNI model in a longitudinal magnetic field. By using the symmetries …
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Nanoscale stress-induced conducting states in functional oxides
… conducting interfaces, such as domain walls and phase boundaries, in an array of material systems is now well established. Whilst the existence of conducting interfaces within otherwise insulating mediums is surprising, exciting new avenues for fundamental research have developed, focussing on …
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Constitutive modeling of Cu-Al-Ni shape memory alloys
Certain alloys can exist in multiple phases, which, in the context of solids, essentially mean multiple crystallographic structures. For example, at certain compositions, a Cu-Al-Ni alloy can exist as a cubic lattice (austenite), an orthorhombic lattice ([beta]'1-martensite) or a monoclinic lattice …
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An Investigation of Protein Interactions and the Relationship to Phase Behavior
… in solution are inherently linked to phase behavior. A fundamental understanding of the relationship is necessary to develop efficient methods for crystallizing proteins. In this investigation, lysozyme second virial coefficient measurements consistently reflect trends in lysozyme …
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Chemical Physics of Hydrazine Under Pressure
… a unique thermodynamic pathway for accessing new phases and reactivity that are inaccessible under ambient conditions. By combining vibrational spectroscopy and synchrotron X-ray diffraction across a wide pressure range, this work establishes a unified picture of the structural, vibrational, and …
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