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 50 for “"Spinodal Decomposition"”.
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Asymptotic behavior in spinodal decomposition
… we study the kinetics of systems undergoing spinodal decomposition, using computational and semi-analytical methods. We use a Cell Dynamical System (CDS) to build effective computational models of spinodal decomposition in a large 3-space isotropic ideal binary alloy system and a well matched …
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Large Scale Simulation of Spinodal Decomposition
Spinodal decomposition is a process in which a system of binary mixture eventually evolves to the separation of two macroscopic phases. Such phase separation occurs in a thermodynamically unstable state. A number of binary mixture experiments have demonstrated the phenomenon of spinodal …
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Non-destructively detecting spinodal decomposition at a distance towards developing gigahertz ultrasonics for in-vessel inspection
… electron microscopy (TEM)-verified evidence of spinodal decomposition and G-phase precipitation. In this thesis, thermal aging is shown to induce SAW peak splitting in spinodally decomposed CASS alloys, correlated strongly with lowered toughness and decreased ductility. Furthermore, statistical …
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Novel approaches for the characterisation of spinodal alloys
… strategies for strengthening alloys. In spinodal alloys, this is achieved by diffusion-controlled elemental clustering, known as spinodal decomposition, during ageing, which produces a compositionally modulated microstructure. This typically confers a large strengthening increment and is …
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Phase-equilibrium-mediated assembly of colloidal nanoparticles
… main mechanisms; (1) cluster formation and (2) spinodal decomposition. In each mechanism, we developed novel, effective, and efficient computational algorithms to elucidate phase-equilibrium assembly structure and formation dynamics of CNPs: (1) a kinetic Monte Carlo (KMC) algorithm for cluster …
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Polymer Gels: Kinetics, Dynamics Studies and Their Applications as Biomaterials
… studies of polymer gels on swelling kinetics, spinodal decomposition, and solution convection in gel matrix; (2) applications of polymer gels in wound dressing, tissue-simulating optical phantom and gel display. The kinetics of gel swelling has been theoretically analyzed by considering coupled …
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The effect of thermal aging and boiling water reactor environment on Type 316L stainless steel welds
… stainless steels and duplex stainless steels. Spinodal decomposition is largely responsible for the well known "475°C" embrittlement that results in drastic reductions in ductility and toughness in these materials, and this process is operative also in welds of either cast or wrought stainless …
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Percolation behavior of diffusionally evolved two-phase systems simulated using phase field methods
… for two dimensional systems evolved through spinodal decomposition and nucleation and growth.
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Particle shape anisotropy and its effects in AlNiCo and Fe-Cr-Co magnet alloys.
… supports the view that this mechanism is spinodal decomposition, which initially produces an homogeneous, fine shape-anisotropic particle microstructure, and by subsequent diffusion during heat treatment achieves a highly ferromagnetic state; all of which are necessary conditions for good …
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As global ambient temperatures continue to rise, with the highest recorded annual averages since 1850 being within the last ten years, problems emerge for species exhibiting temperature-dependent sex determination. This is the process by which the sex of an animal’s embryo is determined based on the temperature of environment in which it is incubated, which can result in skewed sex ratios within a population like in the case of the critically endangered Hawksbill Sea Turtles (Eretmochelys imbricata). Reportedly, 85-95% of Hawksbills sampled in the wild are currently female [3]. This sex-imbalance can negatively impact the species’ ability to procreate, leading to the potential for extinction. Currently, no viable, long-term solutions exist to effectively and safely cool sea turtle eggs while still keeping them within their natural habitat. This research proposes the creation of sea turtle egg incubators designed to achieve a temperature range that will produce a higher percentage of male hatchlings to help rectify this imbalance in habitats heavily affected by climate change. These incubators are designed to be affordable, easy to build and, most importantly, safe for the sea turtle eggs. Three-month-long temperature trials for the incubator were conducted in Jamaica with conservationist community partners at Oracabessa Bay Sea Turtle Project. Results showed that this incubator is not only easy to manufacture and use, but that it successfully regulates the temperature range in favor of more male hatchlings, while also increasing the emergence rate of the hatchlings from 70% in natural nests to over 80%. During one of the hottest months in Jamaica, the incubator, deployed without water changes, doubled the predicted percentage of males produced by natural nests. When provided with cool water changes the incubator quintupled this value. Throughout the months of August to October, the incubator achieved a temperature range that is predicted to produce 85-99% male hatchlings, thus counteracting the feminization phenomenon occurring in nature.
… fabricate at scale via additive manufacturing. Spinodal architected materials, derived from scalable spinodal decomposition processes, offer a promising alternative with aperiodic, double-curvature microstructures that enhance mechanical efficiency at low relative densities. Nevertheless, their …
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Cell dynamical system approach to block copolymers
… a close relation between the block copolymer and spinodal decomposition problems. A detailed numerical study of the CDS model is given, which indicates that hydrodynamic effects are crucial for very late time ordering processes. The strong segregation regime is studied analytically with the aid of …
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Stress Effects on Phase Morphological and Compositional Non-uniformity in Intercalation Compounds
… the recently discovered surface-driven coherent spinodal decomposition. We comprehensively analyze the phase separation kinetics in nanosized systems by considering both the bulk and surface modes of coherent spinodal decomposition within the linear stability theory. It shows that the stress …
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Crystallographic, Morphological and Kinetic Studies of the Alpha-Beta Transformation in the Niobium-Hydrogen System
… single phase solid solution, a region of spinodal decomposition, and several ordered hydride modifications.
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Bijels For Continuous Reactive Separations
… reactors. Bijels are made by triggering the spinodal decomposition of a homogenous mixture of fluids by co-solvent removal; the three dimensional bicontinuous structure arising from spinodal decomposition has several advantages since both the water and the oil phases are co-continuous and …
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Factors Affecting Size and Swelling of Poly(ethylene glycol) Hydrogel Microspheres Formed in Aqueous Sodium Sulfate Solutions
… soon after phase separation by off-critical spinodal decomposition. This technique of producing PEG microspheres with controlled sizes has considerable potential for an array of applications, including the production of modular scaffolds for tissue engineering.
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Stability of Nanoporous Metals
… using a phase-field model to simulate the spinodal decomposition of an ideal system. One phase in the model is then associated with the pore volume while the other phase is associated with the metal ligaments. Small angle neutron scattering was used to quantitatively compare experimental …
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Growth and characterization of epitaxial metastable (gallium arsenide)(1-x)(silicon(2))(x) alloys and (gallium arsenide)(1-x)(silicon(2))(x)/gallium arsenide strained-layer superlattices
… by the formation of an epitaxial interfacial spinodal zone whose height varied from $\approx$20 to 70 nm. The spinodal region consists of lenticular platelets along the (001) growth direction and a Si-rich-(GaAs)$\sb{\rm 1-x}$(Si$\sb2)\sb{\rm x}$/Si-deficient-(GaAs)$\sb{\rm …
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Thermoreversible Gelation, Crystallization and Phase Separation Kinetics in Polymer Solutions under High Pressure
… to determine both the binodal and the spinodal envelops using time- and angle resolved light scattering techniques. At each concentration, a series of rapid pressure quenches with different penetration depths in a range from 0.1 MPa to 3 MPa were imposed and the time evolution of the …
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Large Strain Finite Element Analysis of Spinodal Shell Structures
… efficiency. Architectures derived from spinodal decomposition have promising material properties due to their continuous doubly curved surfaces with minimal stress concentrations. In this work, finite element analysis was used to model spinodal shell structures, allowing the study of the …
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Microphase Separation Studies in Styrene-Diene Block Copolymer-based Hot-Melt Pressure- Sensitive Adhesives
… from a nucleation and growth type mechanism to a spinodal decomposition mechanism for phase separation and ordering. The compatibility of the tackifier with the polystyrene chains had a significant impact on the morphological transitions and microphase separation in adhesive blends. The blends …
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