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 37 for “"void formation"”.
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Void formation in copper and selenium ion irradiated molybdenum.
Thesis: M.S., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 1978
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Investigations on Void Formation in Composite Molding Processes and Structural Damping in Fiber-Reinforced Composites with Nanoscale Reinforcements
… issue during these processing methods is void formation due to incomplete wet-out of the resin within the fiber preform, resulting in discontinuous material properties and localized failure zones in the material. A fundamental understanding of the resin evolution during processing is …
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Atomistic model of void nucleation and growth during electromigration
Void formation due to electromigration is among the most significant reliability problems in the semiconductor industry. To help gain a better understanding of the atomistic processes involved in void formation under electromigration conditions we have used the Embedded Atom Method (BAM) to …
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A new beamline for positron annihilation lifetime spectroscopy
… defects with lifetimes as low as 200ps, to large voids (~10 nm) resulting in lifetimes >50 ns. In addition to experimental development aspects, the materials investigations presented here focus on defects in semiconductor materials produced by ion implantation and focused laser pulses. The PALS …
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A new beamline for positron annihilation lifetime spectroscopy
… defects with lifetimes as low as 200ps, to large voids (~10 nm) resulting in lifetimes >50 ns. In addition to experimental development aspects, the materials investigations presented here focus on defects in semiconductor materials produced by ion implantation and focused laser pulses. The PALS …
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An investigation into thermomechanical fatigue of metal matrix composites
… are used to characterize the thermomechanical deformation behavior of metal matrix composites. Experiments on unreinforced and SiC particulate reinforced Al 2xxx-T4 have been conducted under several mechanical strain-temperature phasing conditions. Based on stress range, substantial improvements …
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TEM Study of a RTO Oxide-Interfacial Layer on Epitaxial-Cobalt Silicide (CoSi2) Formation
… anneal is done by rapid thermal annealing (RTA). Void formation in the CoSi2 film has been observed above the RTA temperatures of 660?C. The voids extend into Si, indicating some Si out-diffusion. The CoSi2 / Si interface is also rough and non-uniform. There is some local epitaxy of CoSi2 on Si. …
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Examination of the small scale slow cookoff behavior of a cast modified double base propellant
… computed tomography to provide qualitative information on void formation due to gradual heating.
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Three-dimensional defect characterization : focused ion beam tomography applied to tin sulfide thin films
… model that assumes a diffusion-driven process of void formation. We show that both models qualitatively support the experimental results, providing insight into process-structure relations that may improve film quality during growth.
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Cobalt silicide characterization
… currents, film uniformity, junction spiking, void formation, sheet resistivity, thermal stability, and agglomeration. There are four process variables in this study: the first rapid thermal anneal (RTA) temperature and ramp rate, the Co and TiN removal time, and the second RTA temperature. …
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Comparison of Additively Manufactured and Wrought 17-4 PH Stainless Steels in Ultra Low Cycle Fatigue
… of AM metals are not yet well understood. Void formation during the AM fabrication process has potential to affect performance. This study compares the performance of heat-treated and non-heat-treated AM and wrought 17-4PH stainless steel in Ultra Low Cycle Fatigue. To understand ULCF …
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Chaos and Thermalization in Quantum Many-Body Systems and Gravity
… help of concepts and techniques from quantum information theory. We identify a universal dynamical process in the Heisenberg evolution of operators known as void formation, and use it to provide a new characterization of information spreading in chaotic systems. We also develop a technique …
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Thermophysical properties of glass and glass-ceramic composites
… decrease in thermal conductivity due to void formation by relaxation of the elastically bent fibers by viscous flow of the matrix. Thermal conductivity of iniaxial carbon fiber reinforced lithia-aluminosilicate glass-ceramic was over ten times higher parallel to the fibers than …
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Development of water-soluble PEG-based binder systems for Ti Metal Injection Moulding
… process and reveal the mechanism of void formation in the PEG/polymethyl methacrylate (PMMA) binder systems and how to eliminate these voids. This study may benefit the development of environment-friendly and clean binder systems suitable for Ti-MIM. The main findings are summarised …
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Simulated Material Erosion from Plasma Facing Components in Tokomak Reactors
… and ejected material. Melting and bubble/void formation has been observed on the tungsten surface. The tungsten surface shows evidence of melt-layer flow and the existence of voids and cracks in the exposed material. The ejected material does not show direct evidence of liquid material …
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Lyocell Fiber-Reinforced Cellulose Ester Composites-Manufacturing Considerations and Properties
… absorption during matrix application and void formation during consolidation. Melt processing technique using alternating sandwich structure of fabrics and CAB films produced composites with impressive appearance, low void contents and low moisture absorption. However, SEM results revealed …
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Thermoplastic composite consolidation
… the ply interfaces is achieved resulting in the formation of strong interply bonds and the process-induced residual stress is minimized to ensure superior mechanical performance. The void formation and the consolidation mechanism were studied experimentally. A refined model was developed to …
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Modeling the pultrusion process to obtain low void fraction composites
… area for improving composites is the fraction of voids in the final product. The presence of voids in a composite decreases the Interlaminar Shear Strength, provides a site for the formation of fractures, and increases the susceptibility of the part to outside contaminants.;In this work, the …
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Designing Core/Alloy Nanoparticles by Manipulation of Interfacial Oxidation and Atomic Diffusion
… shell thickness, oxidation results in Kirkendall void formation essentially allowing for control over the morphology of hollow core/alloy NP. Formation of an outer oxide shell creates a stainless steel-like interface, which results in passivation from further oxidation. Finally, I describe Mn …
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Modeling microdefects formation in crystalline silicon : the roles of point defects and oxygen
… fundamental understanding of the mechanisms for formation of such microdefects through the development of models, theoretical analysis and large-scale simulation. Two major problems have been addressed. First, following the work of T. Sinno [150] and T. Mori [108], models have been developed for …
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