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 93 for “"Low Thermal Conductivity"”.
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Ultra low thermal conductivity in layered disordered crystalline materials
… presents an alternative route to achieve ultralow thermal conductivity in a dense solid. Thin films of disordered layered crystalline materials were deposited using Modulated Elemental Reactants (MER) method. Cross-plane thermal conductivity was measured using Time-Domain Thermo Reflectance …
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DISCOVERY OF HIGH ENTROPY CERAMICS WITH LOW THERMAL CONDUCTIVITY THROUGH MACHINE LEARNING
… their unique composition and diverse properties. Low thermal conductivity (κ) makes them promising materials for high-temperature applications. However, predicting the thermal properties of HECs is challenging due to the complex nature of their atomic interactions. This project explores the use of …
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Assessing low thermal conductivity of bricks which contain rice husk, corn cob and waste tea as an additive material
… resources and reduction of energy requirements. Thermal and mechanical brick properties play an important role in designing modern buildings. Decreasing thermal conductivity is the dominant factor in reducing heat that could be transferred to or from the building. The main objective of this study …
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Transport of phonons and electrons in thermoelectric materials and graphene
… or vice versa, require both extremely low thermal conductivity and high thermoelectric power factor. However, a good understanding of low thermal conductivity is still lacking even for several good thermoelectric materials that have been studied over several decades. For the information …
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Thermoelectric properties in gallium telluride-gallium antimonide vacancy compounds
… large Seebeck coefficient, large electrical conductivity and low thermal conductivity, are of great importance in solid state cooling and power generation. Solid solution formation is one effective method to achieve low thermal conductivity by phonon scattering due to mass and strain field …
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Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process
Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility of aerogels while retain the low thermal conductivity of silica aerogels. We …
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Synthesis and characterization of nanofluids for cooling applications
Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids that are required in numerous industrial sectors. Recently submicron and high aspect ratio particles (nanoparticles and nanotubes) were introduced into the heat transfer fluids to enhance …
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The properties of concrete containing coconut shell as fine aggregate
… (FCS) as a partial replacement of sand and its low thermal conductivity applications. The first part of the research focused on the characterisation properties of fine coconut shell and sand through sieve analysis, laser diffraction sieve, specific gravity tests, bulk density tests, scanning …
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THERMAL CONDUCTIVITY OF THIN FILM NIOBIUM DISELENIDE FROM TEMPERATURE-DEPENDENT RAMAN
… diselenide (NbSe2) possess a high electrical conductivity and low thermal conductivity, making it a candidate for thermoelectric devices. While the electronic properties of (NbSe2) has been relatively explored, the lateral thermal conductivity for (NbSe2) has remained unknown. In this report, …
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Sealing of partially evacuated solar solar collectors
… The proposed collector contains 15 torr of low thermal conductivity gas to suppress conduction losses from spurious gases arising in the collector.<br/><br/>A study was undertaken, and is shown, to predict the loss of vacuum in the polymer sealed collectors; for various vacuum sealing …
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Stochastic Models of Surface Limited Electronic and Heat Transport in Metal and Semiconductor Contacts, Wires, and Sheets---Micro to Nano
… roughness in coupled mechanical, electronic and thermal processes in N/MEMS and semiconductor devices in the 10 nm - 1 mum range. A model is presented to estimate roughness rms Delta and autocorrelation L from experimental surfaces and edges, and subsequently generate statistical series of rough …
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Stochastic Models of Surface Limited Electronic and Heat Transport in Metal and Semiconductor Contacts, Wires, and Sheets — Micro to Nano
… roughness in coupled mechanical, electronic and thermal processes in N/MEMS and semiconductor devices in the 10 nm - 1 m range. A model is presented to estimate roughness rms and autocorrelation L from experimental surfaces and edges, and subsequently generate statistical series of rough …
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Methods for increasing the thermal conductivity of ultra-high molecular weight polyethylene (UHMWPE)
… molecular weight polyethylene with high thermal conductivity by way of polymer chain orientation. The first portion of this report surveys current research involving polyethylene chain orientation and manufacturing. This section includes analysis of shish-kebab morphology, past polymer …
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First principles study of ternary skutterudites
… of thermoelectric materials because they show low thermal conductivity with filled voids in their structures. To investigate the potential of ternary skutterudites as thermoelectric materials, first-principles calculations are performed on filled and unfilled CoSn1.S1.S5, CoSn1.5Se1.5, …
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Experimental investigations of using silica aerogel to harvest unconcetrated sunlight in a solar thermal receiver
Significant demand exists for solar thermal heat in the mid-temperature ranges (120 oC – 220 oC). Generating heat in this range requires expensive optics or vacuum systems in order to utilize the diluted solar energy flux reaching the earth’s surface. Current flat plate solar collectors have …
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Igneous intrusions and thermal evolution in the Raton Basin, CO-NM: contact metamorphism and coal-bed methane generation
… from long emplacement durations and the very low thermal conductivity of coal is responsible. Intrusions may be very important for methane generation in sedimentary basins.
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The effect of roughness element thermal conductivity on turbulent convection.
Many flows of engineering interest occur over surfaces that exhibit roughness with thermal conductivities much lower than common metals and alloys. This is especially true of in-service gas turbine blades with surface depositions. Depending on the local convection coefficients, low thermal …
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Multifunctional polymeric foams: preparation, characterization, and environmental aspects
… are characterized by a unique combination of low density, high mechanical properties, and low thermal conductivity. Moreover, these properties can be tuned to specific applications. In contrast to traditional foams, where porosity is formed during the foaming process, porosity in syntactic …
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Experimental and ANSYS investigation on the aerogel envelopes for energy-efficient building
… as an insulating material due to their extremely low thermal conductivity. Very often the benefits of transparency as well as strength is ignored due to its brittleness. An effort has been taken to increase the strength using vacuum seal while maintaining their transparency. To understand the …
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Thermal Characterization of Graphitic Carbon Foams for Use in Thermal Storage Applications
… foams are currently being studied for use as thermal conductivity enhancers (TCEs) in thermal energy storage (TES) systems. TES systems store energy using the latent heat capacity of phase change materials (PCMs). Due to the low thermal conductivity of most PCMs, TCEs are necessary to evenly …
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