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The thermal properties of hydrate bearing sediments remain poorly studied, in part due to measurement difficulties inside the hydrate stability envelope. In particular, there is a dearth of experimental data on hydrate-bearing sediments, and most available measurements and models correspond to bulk gas hydrates. However, hydrates in nature largely occur in porous media, e.g. sand, silt and clay. The purpose of this research is to determine the thermal properties of hydrate-bearing sediments under laboratory conditions, for a wide range of soils from coarse-grained sand to fine-grained silica flour and kaolinite. The thermal conductivity is measured before and after hydrate formation, at effective confining stress in the range from 0.03 MPa to 1 MPa. Results show the complex interplay between soil grain size, effective confinement and the amount of the pore space filled with hydrate on the thermal conductivity of hydrate-bearing sediments.

The goal is to perform heat measurements examine of selected roofing material samples. Those roofing materials are asphalt shingles, ceramics, and cedar. It’s important to understand the concept of heat transfer, which consists of conduction, convection, and radiation. Research work was reviewed on different infrared devices to see which one would be suitable for conducting my experiment. In this experiment, the main focus was on a specific property of radiation. That property is the emissivity, which is the amount of heat a material is able to radiate compared to a blackbody. An infrared measuring device, such as the infrared camera was used to determine the emissivity of each sample by using a measurement formula consisting of certain equations. These equations account for the emissivity, transmittance of heat through the atmosphere and temperatures of the samples, atmosphere and background. The experiment verifies how reasonable the data is compared to values in the emissivity table. A blackbody method such as electrical black tape was applied to help generate the correct data. With this data obtained, the emissivity was examined to understand what factors and parameters affect this property of the materials. This experiment was conducted using a suitable heat source to heat up the material samples to high temperature. The measurements were taken during the experiment and displayed by the IR camera. The IR images show the behavior of surface temperatures being distributed throughout the different materials. The main challenge was to determine the most accurate emissivity values for all material samples. The results obtained by the IR camera were displayed in figures and tables at different distances, which was between the heap lamp and materials. The materials exhibited different behaviors in temperature and emissivity at certain distances. The emissivity of each material varied with different temperatures. The results led to suggestions of certain materials that could be beneficial and disadvantageous in energy and cost savings during cold and hot seasons of the year. Also this led to some uncertainties in the data generated. Overall, this can support in exploring other ideas to increase energy and cost saving consistently during both season by using a material that can change its color and density based on a high or low temperature.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science. March 28, 2013 / The search for solutions to the important differential equations arising in extended surface heat transfer continues unabated. Extended surfaces, in the form of longitudinal fins are considered. First we consider the steady state problem and then the transient heat transfer models. Here, thermal conductivity and heat transfer coefficient are assumed to be functions of temperature. Thermal conductivity is considered to be given by the power law in one case and by the linear function of temperature in the other; whereas heat transfer coefficient is only given by the power law. Explicit analytical expressions for the temperature profile, fin efficiency and heat flux for steady state problems are derived using the one-dimensional Differential Transform Method (1D DTM). The obtained results from 1D DTM are compared with the exact solutions to verify the accuracy of the proposed method. The results reveal that the 1D DTM can achieve suitable results in predicting the solutions of these problems. The effects of some physical parameters such as the thermo-geometric fin parameter and thermal conductivity gradient, on temperature distribution are illustrated and explained. Also, we apply the two-dimensional Differential Transform Method (2D DTM) to models describing transient heat transfer in longitudinal fins. Furthermore, conservation laws for transient heat conduction equations are derived using the direct method and the multiplier method, and finally we find Lie point symmetries associated with the conserved vectors.

Les matériaux de protection incendie sont largement utilisés pour assurer la sécurité des usagers des infrastructures. Les normes de protection incendie évoluant régulièrement, les matériaux doivent être de plus en plus performants. Ceux-ci sont généralement des mortiers constitués d’oxydes réfractaires et isolants. L’objectif de ce travail est de mettre au point un composite coupe-feu 4 h applicable par projection mais également de déterminer ses propriétés thermiques et mécaniques.Dans une première partie, cette étude reprend les différentes étapes de l’élaboration d’un matériau de protection incendie, après la présentation de la démarche qui a guidé l’élaboration de nos matériaux, nous nous sommes intéressés plus particulièrement à la composition chimique de la matrice ainsi que celle du ciment. Leurs propriétés thermiques et mécaniques ont été passées en revue.Les matières premières nécessaires à l’élaboration d’un mortier ont ensuite été sélectionnées. L’évolution, respectivement de la conductivité thermique, de la diffusivité, de la porosité, de la chaleur spécifique et des propriétés mécaniques des mortiers choisis en fonction de la nature et de la quantité de charges incorporées à la matrice a été étudiée. Une description des divers modèles analytiques et numériques permettant la représentation de la conductivité thermique et du module d’Young des matériaux a permis de développer un modèle capable de prédire le comportement thermique et mécanique des composites en fonction de la nature et de quantité de charges ajoutées.Dans une seconde partie, la cinétique de la réaction d’hydratation du plâtre afin de maîtriser les temps de prise et pour faciliter la production des projetés dans la chaîne industrielle a été étudiée. L’influence sur la cinétique d’hydratation, de la composition chimique du plâtre, de sa granulométrie et de l’ajout d’adjuvants couramment utilisés dans l’industrie plâtrière, a également été traitée.10A l’issue de cette étude, deux formulations de composites projetables ont été mises au point. / Fire protection materials are widely used to ensure the safety of users of the infrastructure. Standards of fire protection regularly operating, the materials must be more efficient. These are generally composed of refractory mortar and insulating oxides. The objective of this work is to develop a firewall composite 4 h applied by projecting but also to determine the thermal and mechanical properties.In the first part, this study describes the various stages of the development of a fire protection material, after the presentation of the approach that has guided the development of our materials, we are interested especially in the chemical composition of the matrix and that of the cement. Their thermal and mechanical properties have been reviewed.The raw materials for the preparation of mortar were selected. The evolution respectively of thermal conductivity, diffusivity, porosity, specific heat and the mechanical properties of mortars chosen according to the nature and amount of the fillers incorporated in the matrix has been studied. A description of the various analytical and numerical models for the representation of the thermal conductivity and Young's modulus of the materials led to the development of a model able to predict the thermal and mechanical behavior of composites based on the nature and amount of charges added.In a second part, the kinetics of the hydration reaction of gypsum to control setting time and to facilitate the production of the composite in the industrial chain was studied. The influence on the kinetics of hydration, of the chemical composition of the gypsum, particle size distribution and the addition of adjuvant commonly used in the plaster industry, has also been treated.At the end of this study, two formulations of composites applied by projection were developed.

Titanium nitride coatings have been widely applied and studied as high temperature diffusion barrier for silicon devices in microelectronics, wear resistant coatings in turbine blade materials, and materials for future high temperature nuclear reactors. In order to enhance the material property, superlattices is one of artificially engineered protective coatings, such as AlN/TiN and TaN/TiN multilayered films. Epitaxial cubic multilayer films, TaN/TiN and AlN/TiN nanolayers were grown on Si(001) by Pulsed Laser Deposition (PLD) with various nanolayer thicknesses and number of interfaces. Microstructural studies include X-ray diffraction (XRD), transmission electron microscopy (TEM), and high resolution TEM with ion-irradiation experiments. Electrical, mechanical and thermal property studies were conducted for the interface and size effects on the nanolayers by using nanoindentation and Transient Thermo-Reflectance (TTR) methods. The microstructural and hardness study on TaN/TiN films with ion irradiation (12 keV and 50 keV He ) suggest no obvious microstructural or mechanical behavior change due to ion irradiation. In addition, titanium nitride that serves as effective diffusion barrier to prevent the inter-diffusion between the nuclear fuel and the cladding material was studied in order to enhance the lifetime of the fuels and the reliability of the fuel claddings. The TiN has good adhesion with the stainless steel and higher hardness than that of bulk TiN on the stainless steel. Thermal conductivity test demonstrates that thin TiN film has compatible thermal conductivity as the MA957 and HT-9 bars. The size effect on electrical resistivity is dominant in both of the epitaxial cubic and the polycrystalline TiN thin films in the thickness ranged from ~60 nm down to ~35nm. In the TaN/TiN multilayer, the grain scattering effect on resistivity is dominant rather than interface influence on the resistivity with comparing epitaxial cubic phase and polycrystalline phase. The microstructure and hardness studies of the AlN/TiN multilayer films with He implantation present that the suppression of amorphization in AlN layers and the reduction of radiation-induced softening were achieved in all nanolayer films. Radiation tolerance was found to be size dependent and the layer thickness leading to the highest radiation tolerance was around 10 nm. In addition, the embedded epitaxial cubic AlN with cladding TiN nanolayers showed higher effective thermal conductivity than that of AlN single layer as well as the embedded polycrystalline AlN in the thickness ranged from 10 nm down to 2 nm. It confirms a suppressed size effect, which reduces the amount of decrease in through-plane thermal conductivity.

The focus of this study was to design and build a guarded hot box to test the R-Value of building materials. The Riverside Energy Efficiency Laboratory is looking to expand their testing capabilities by including this service. Eventually, the laboratory will become energy star certified. A guarded hot box facility consists of two boxes maintained at specific temperatures and a guard box around each one that is maintained at the same temperature as the box it surrounds. The ASTM C1363 standard was used as guide for the construction and testing of sample specimen. This standard called for an air velocity profile uniform within 10 percent of the average. Velocity tests were performed with various different configurations to give a uniform velocity. Although the velocity did not meet standards, the configuration chosen included a piece of 1/4" pegboard placed 2" away from the top and the bottom of the inner box. By using the known overall heat added and removed from the system, as well as all the heat losses the heat transferred through the specimen and its R-Value can be calculated. The uncertainty of the R-Value and the accuracy of the testing facility gave conflicting results. Future experiments will use improved testing methods that include differential thermocouples to obtain better uncertainty for the R-Value calculations.

Thesis(M.S.)--Case Western Reserve University, 2009 / Title from PDF (viewed on 2010-01-28) Department of EMC - Mechanical Engineering Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center