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 26 for “"Thermal Aging"”.
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On Thermal Aging Prevention in Polymer Core Composite Conductor Rods
… to understand and reduce the impact of thermal aging on the core rods. The research demonstrates that the source of flexural failure in the rods moves from predominantly physical aging to predominantly chemical aging as a function of time and temperature, a brand new explanation that is …
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The hardening of Type 316L stainless steel welds with thermal aging
… Laboratory is investigating the effect of thermal aging on the physical properties of stainless steel piping. Stainless steel piping, of the same standards of that used in boiling water reactors, was welded and aged at temperatures of 300-400*C for 1,000 - 40,000 hours. The properties of …
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Effects of sterilization, conditioning, and thermal aging on the retention of zirconia hybrid abutments
… of sterilisation, conditioning methods, and thermal ageing on the retention strength of two-piece zirconia abutments. A total of 128 stock zirconia abutments were divided into 4 groups, each including 32 abutments. The groups were categorized based on the conditioning parameters used: …
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The effect of thermal aging and boiling water reactor environment on Type 316L stainless steel welds
The thermal aging and consequent embrittlement of materials are ongoing issues in cast 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 …
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Effects of thermal aging on Stress Corrosion Cracking and mechanical properties of stainless steel weld metals
… program was designed to explore the effect of thermal aging on the SCC crack growth rate in weld materials for type 316 and 304 stainless steels. An autoclave facility was designed and constructed for the measurement of SCC crack growth rates under BWR conditions and testing was underway at the …
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Mechanical Properties and Durability of Natural Rubber Compounds and Composites
… this research was to investigate the effect of thermal degradation upon the mechanical properties of natural rubber compounds and apply those effects to the life prediction of off axis 2-ply cord rubber laminates. The work examined both the quasi-static and dynamic mechanical properties of two …
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Inferring Microstructural Change via Non-Contact Ultrasonic Property Measurements
… precipitation, and grain growth due to thermal aging and irradiation in binary Cu-3at%Ti, where a clear relationship exists between thermal diffusivity, surface acoustic wave (SAW) frequency and microstructure. A model RPV alloy, which experiences embrittlement via the same mechanisms as …
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Microstructure evolution in Alloy 709 at 550 and 650 °C
… austenitic stainless steel is studied after thermal aging at 550°C and 650°C. The microstructure is characterized using variety of techniques. The alloy shows excellent thermal stability at its working temperature 550°C, while its microstructure evolves rapidly at 650°C with complex …
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Characterization of bending fatigue mini-specimens for nuclear materials
… 30.88% for the as-received and 26.51% for the thermal aging for Incoloy alloy MA956. The thermal aging process had little impact on the mini-specimens fatigue life. The analysis of error propagation of specimen's stress has been observed that the most of the error was in deflection …
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Modeling and prediction of residential service transformer’s demand considering high penetration of electric vehicles
… for distribution transformer sizing and thermal aging assessment. Traditional sizing methods based on peak demand and diversity factors fail to capture the dynamic, time-varying nature of residential loads influenced by electric vehicles charging. In this thesis, a data-driven model is …
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Caracterização do resíduo pós-industrial de PVDF visando potencial utilização via reciclagem primária
… coexistence of alfa end beta phase. The thermal aging was responsible for promoting thermo-oxidation in the samples which lead to secondary crystallization, however, this secondary crystallization did not affect significantly the materials thermal stability and mechanical properties, …
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Synthesis and Application of Ceramic Paste for High-Temperature Electronic Packaging
… developed for high-temperature electronic packaging. Nano aluminum nitride and nano-silica powders were embedded to promote the paste curing process, limit the grain growth, and increase its bond shear strength. The chip-to-substrate bond strength was enhanced and met the MIL-STD requirements …
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Evaluating heavy-duty diesel engine aftertreatment devices with a split exhaust configuration
… Effects (DECSE) program. In order to perform thermal aging of the DOC and lean-NOx catalysts simultaneously and economically, each catalyst was sized to accommodate half of the engine exhaust flow. Simultaneous catalyst aging was then achieved by splitting the engine exhaust into two streams …
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Nondestructive Analysis of Advanced Aerospace Materials via Spectroscopy and Synchrotron Radiation
… response and failure mechanisms. In this study, thermal barrier coating samples applicable to turbine blades of jet engines were studied using Raman and Photoluminescence spectroscopy as well as Synchrotron X-ray diffraction while Kevlar based fiber composites applicable to ballistic resistant …
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Effects of tooth quality, tooth structure, and cement mixing ratios on dental adhesion
… properties. The effects of chemical treatment, thermal dehydration and rehydration on dentin quality were examined. The contribution of enamel to adhesion was evaluated by comparing the adhesion of dentin samples that had the enamel ground off prior to bonding with dentin samples that retained …
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The effects of electron beam irradiation on additives present in food-contact polymers.
… appear to be different to those produced on thermally aging stabilized polymers. Irradiation was also found to give transformation products farmed via the cleavage of tertiary butyl groups from the parent molecules, and such compounds are not produced during the thermal aging of similar …
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Non-destructively detecting spinodal decomposition at a distance towards developing gigahertz ultrasonics for in-vessel inspection
… service, losing ductility and toughness due to thermal and irradiation aging. Techniques to monitor their health cannot be easily applied in the field due to their destructive, expensive, or immobile nature. Thus, non-destructive evaluation (NDE) methods are sought to monitor and evaluate the …
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Polylactic Acid based Blends and Composites for Material Extrusion 3D Printing: Formulation, Characterization, and Processing
… importantly, CNC-g-ECO demonstrated enhanced thermal stability and completely mitigated discoloration and thermal aging, which are common issues in CNC-based composites. Finally, this thesis investigated the effects of CNC treatment on the morphology, properties, and material extrusion …
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Microstructural evolution and mechanical behavior in nickel based alloys for very high temperature reactor
… and their long-term degradation process during thermal aging. First, mechanical properties of both alloys were studied by performing tensile tests at three different strain rates and at temperatures up to 1000ºC. This range covers time-dependent (plasticity) to time-independent (creep) …
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Phase transitions of poly (l-lactic acid) in bulk and in solution
… C is found from pycnometry measurements. After thermal aging at this temperature, amorphous PLLA samples exhibit maximum excess enthalpies of relaxation. These observations are ascribed to the evolution of the amorphous phase of PLLA towards its equilibrium state via primary nucleation at …
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