In the near future, Gen II, III, and IV nuclear reactors will be in operation. UO2 is a common fuel for reactors in each of these generations and molten salts are used as coolant/fuel in Gen IV molten salt reactors. This thesis investigates potential ways to measure thermal conductivity for these materials: Raman thermometry for UO2 and a needle probe for molten salts. Four Raman thermometry techniques are investigated in this thesis: The Two Laser Raman (TLR), Time Differential Domain Raman (TDDR), Frequency Resolved Raman (FRR), and Frequency Domain Raman (FDR). The TLR is a steady state method used with a thin film. The TDDR and FRR are both time domain methods used with thin cantilever samples. The FDR is a frequency domain method used with a thermally thick sample. Monte Carlo like simulations are performed for each technique. In the simulations, the affect introduced uncertainty has on the measurement of thermal conductivity and thermal diffusivity is measured. From the results, it is recommended that the TLR should be used for measuring thermal conductivity and the FRR used for measuring thermal diffusivity. The TDDR and FDR were heavily affected by the uncertainty which resulted in inconsistent measured thermal properties. For measuring the thermal conductivity of molten salt, a needle probe was designed and manufactured to withstand the corrosive environment found in using molten salts. The probe uses modulated joule heating and measures the temperature rise in a thermocouple. The phase delay and temperature amplitude of the thermocouple are used in determining the thermal conductivity. A new thermal quadrupole based analytical solution, which takes into consideration convection and radiation, to the temperature rise of the probe is presented. The analytical solution is verified using a numerical solution found using COMSOL. Preliminary data was obtained with the probe in water.

Electromagnetic induction (EMI) has been used in archaeology for decades, but still lags in use and development when compared to magnetometry and ground-penetrating radar. While it has become more popular than electrical resistivity area survey, it is now less commonly used than electrical resistivity tomography. The EMI method is likely underutilized due to drift problems and a lack of multi-sensor, vehicle-towed systems capable of rapid, high-density data collection. In this article we demonstrate not only the effectiveness of EMI survey, but a case where entire villages would have remained undetected without it. At the Singer-Hieronymus Site in central Kentucky, USA, a vehicle-towed frequency domain EMI survey detected the location of plazas, residential areas, and trash disposal areas across multiple Fort Ancient villages that contained both intact and heavily disturbed deposits. Additionally, three new villages were revealed. Through this process, we discovered how Fort Ancient village dynamics may be studied through a geophysical investigation of village shape, size, and spatial organization.

>Magister Scientiae - MSc / The production procedure of a CsHS04-Si02 composite membrane was optimized in order to obtain the highest possible H2:C02 and H2:C~ Idea selectivity permeance. The optimized membrane preparation procedure led to the preparation of membranes with Idea selectivity of 5 and 10 towards H2:C~ and H2:C02 respectively. The H2 permeance value is on average 0.15 umol- s-l·m-2.Pa-I. The reproducibility of the optimized membrane was further investigated and was found to be satisfactory. An attempt was made to discover the gas transport mechanism of H2, C~ and C02. Gas permeance measurements were carried out as a function of time and temperature (between 25-180°C) using H2, C~ and C02 as analyte gases. XRD, TGA and impedance spectroscopy were used to identify the phases of CsHS04 within the membrane. The gas permeation mechanism was found to be a combination of Knudsen diffusion and solution diffusion. The pores that allow Knudsen diffusion (allow transport of Hi, CH4 and C02) are believed to be located at the CSHS04 crystal phase boundaries. In parallel, H2 diffuses selectively through the lattice of phase II/III of CsHS04 ..

The US navy has a critical need for air independent advanced electric power sources to replace batteries in unmanned undersea vehicles (UUVs). Solid oxide fuel cells (SOFCs) are being considered as one potential replacement option. However, SOFCs typically operate using atmospheric air as their oxidant which is not an option for this underwater application. For this application, pure pressurized oxygen would be used as the oxidant which motivates the search for a cathode material which would be optimal for a high oxygen partial pressure environments. Specifically, this research focuses on cathode materials which can exploit the unique operating conditions required for UUVs. The operation in 100% oxygen atmosphere rather than air provides a significant opportunity. This is because oxygen surface exchange and bulk transport through the cathode is mediated through point defects whose concentrations are sensitive to the partial pressure of oxygen in the atmosphere surrounding the cathode. Oxygen bulk transport along with oxygen surface exchange are the rate controlling steps in oxygen reduction and incorporation at the cathode. The focus of this research is to examine the relationship between oxygen partial pressure and its effect on SOFC cathode performance for two different families of cathode materials, namely strontium doped lanthanum manganite, and a relatively new class of cathode materials, rare-earth nickelates. The experimentally measured relationship between cathode polarization and oxygen partial pressure will be correlated with the underlying transport and surface exchange processes in both families of materials.

The European Green Deal 2020 goals for reducing emissions are enforcing rules on the energy performance of buildings. Therefore thermally insulating materials used as coatings are researched to reduce the energy emissions of buildings. An essential field of interest are nanomaterials. Traditional aerogel is a nanomaterial used for insulating applications due to its high porosity and large surface area, resulting in a longer path for heat to travel. However the cost and manufacturing process are highly energy demanding. Svenska Aerogel AB produces Quartzene® (Qz), a silica-based nanomaterial with similar properties as traditional aerogel. Qz can be incorporated into different paint systems to improve their thermal insulating properties. The aim of this project was to investigate the thermal insulating effects of Qz on three different painting systems (A, B, and C). Samples were moulded and their thermal properties were measured with TPS (Transient Plane Source). The thermal conductivity decreased as the wt% of Qz increased, up until around 10 wt% for system C. It became apparent that at higher wt%, it became harder to properly mix the samples into a good dispersion. The thermal conductivity started to increase above 10 wt%. Experiments showed that bigger particles were easier to mix into the paint than smaller.

A greenhouse experiment was conducted to determine the interactive effects of water salinity, volume of water applied at each irrigation, sodium adsorption ratio and rhizobial strain upon 15 plant growth parameters of Phaseolus vulgaris L. Four levels of water salinity (ECW 0.4, 3.0, 6.0, or 9.0 mmho/cm), three levels of water volume (200, 400, or 800 ml per pot), three levels of SAR (4, 16, or 64) and three strains of Rhizobium phaseoli (K-17, K-47, or K-52) were used. The treatments were replicated with all possible combinations. Data were subjected to analysis of variance, multiple comparisons, and path coefficient analysis.

To improve measurement reliability and repeatability and resolve the orders of magnitude discrepancy between the two different measurements (via reduced model transient electrothermal and lock-in IR thermography), this dissertation details the development of three complementary methods to accurately measure the thermal properties of the natural and synthetic Nephila (N.) clavipes spider dragline fibers. The thermal conductivity and diffusivity of the dragline silk of the N. clavipes spider has been characterized by one research group to be 151-416 W m−1 K −1 and 6.4-12.3 ×10−5 m2 s −1 , respectively, for samples with low to high strains (zero to 19.7%). Thermal diffusivity of the dragline silk of a different spider species, Araneus diadematus, has been determined by another research group as 2 ×10−7 m2 s −1 for un-stretched silk. This dissertation seeks to resolve this discrepancy by three complementary methods. The methods detailed are the transient electrothermal technique (in both reduced and full model versions), the 3ω method (for both current and voltage sources), and the non-contact, photothermal, quantum-dot spectral shape-based fluorescence thermometry method. These methods were also validated with electrically conductive and non-conductive fibers. The resulting thermal conductivity of the dragline silk is 1.2 W m−1 K −1 , the thermal diffusivity is 6 ×10−7 m2 s −1 , and the volumetric heat capacity is 2000 kJ m−3 K −1 , with an uncertainty of about 12% for each property

In situ planetary effective thermal conductivity measurements are typically made using a long needle-like probe, which measures effective thermal conductivity in the probe‟s radial (horizontal) direction. The desired effective vertical thermal conductivity for heat flow calculations is assumed to be the same as the measured effective horizontal thermal conductivity. However, it is known that effective thermal conductivity increases with increasing compressive pressure on granular beds and horizontal stress in a granular bed under gravity is related to the vertical stress through Jaky‟s at-rest earth pressure coefficient. No research has been performed previously on determining the anisotropic effective thermal conductivity of dry granular beds under compressive uniaxial pressure. The objectives of this study were to examine the validity of the isotropic property assumption and to develop a fundamental understanding of the effective thermal conductivity of a dry, noncohesive granular bed under uniaxial compression. Two experiments were developed to simultaneously measure the effective vertical and horizontal thermal conductivities of particle beds. One measured effective thermal conductivities in an atmosphere of air. The second measured effective thermal conductivities in a vacuum environment. Measurements were made as compressive vertical pressure was increased to show the relationship between increasing pressure and effective vertical and horizontal thermal conductivity. The results of this experiment show quantitatively the conductivity anisotropy for different materials. Based on the effective thermal conductivity models in the literature and results of the two experiments, a simple model was derived to predict the increase in effective vertical and horizontal thermal conductivity with increasing compressive vertical applied pressure of a granular bed immersed in a static fluid. In order to gain a greater understanding of the anisotropic phenomenon, finite element simulations were performed for a vacuum environment. Based on the results of the finite element simulations, the simple derived model was modified to better approximate a vacuum environment. The experimental results from the two experiments performed in this study were used to validate both the initial simple model and the modified model. The experimental results also showed the effects of mechanical properties and size on the anisotropic effective thermal conductivity of granular beds. This study showed for the first time that compressive pressure-dependent effective thermal conductivity of granular beds is an anisotropic property. Conduction through the fluid has been shown to have the largest contribution to the effective thermal conductivity of a granular bed immersed in a static fluid. Thermal contact resistance has been shown to have the largest influence on anisotropic effective thermal conductivity of a granular bed in a vacuum environment. Finally, a discussion of future work has been included.

Flat plate heat pipes are very efficient passive two-phase heat transport devices. Their high e'ciency and low mass are desirable in the aerospace and electronics industries. The highly competitive nature of the thermal management industry results in little awareness of the capabilities of at plate heat pipes, which has resulted in only a few applications of the technology. In the year 2000 a research and development project sponsored by Space Dynamics Laboratory was launched to investigate building carbon-based at heat pipes. The at conguration is desireable to incorporate many components onto one thermal management system. Development led to the adoption of the term "Channel Panel" because of the orthogonal grid of channels used as the capillary structure. Work to date has veried the utility and basic function of this technology but has not resulted in a standard method for the design and fabrication of channel panels. This study investigates and evaluates currently available and relevent models useful for the design of channel panels, investigates issues with fabrication, and makes suggestions for future development. Shallow pool boiling is shown to be an appropriate model for the critical heat ux of boiling in at plate heat pipes and provides a means for estimating the convective heat transfer coe'cient. Previous work by Neal Hubbard is modied and shown to accurately couple the geometry and operating limits of a channel panel. Experiments verify the analytical predictions of these models. Issues in the fabrication of channel panels are reported as well as standard procedures for cleaning and lling. The nal result is a standard method for the initial design phase of channel panel at plate heat pipes.

Afin de proposer une alternative aux supercondensateurs utilisant des électrolytes aqueux sous forme liquide produits par la société Hutchinson, ces travaux de thèse ont porté sur le développement de gels ioniques, composés de polymères réticulés gonflés par un liquide ionique, pouvant être utilisés comme électrolytes. L’objectif est donc ici de synthétiser des membranes auto-supportée, de faible épaisseur (e = 100 µm) et de haute conductivité ionique. Les deux premières stratégies de synthèse, basé respectivement sur la préparation de réseaux de poly(1,2,3-triazolium)s et sur la réticulation de copolysiloxanes, n’ayant pas permis d’obtenir de matériaux avec des propriétés satisfaisantes, des films de polyacrylates contenant des liquides ioniques imidazoliums ont été développés. Grâce à l’insertion de hauts taux de cette phase liquide à l’intérieur de ces ionogels, jusqu’à 70 w%, des conductivités supérieures à 10-3 S cm-1 à 30°C ont pu être atteintes, tout en gardant une bonne tenue mécanique à faible épaisseur. Ces électrolytes ont pu être caractérisés électrochimiquement et ont démontré qu’ils permettaient de préparer des cellules supercapacitives fonctionnelles. Cependant, les faibles capacités obtenues indiquent un faible remplissage de la porosité des électrodes, qui est limitant pour l’échange des charges. La poursuite de ces travaux est donc nécessaire pour optimiser ces matériaux, ainsi que les montages utilisés, mais ces gels s’avèrent malgré tout prometteurs et ont pu permettre de préparer des cellules de dimensions équivalentes aux systèmes commerciaux / In order to offer an alternative to the supercapacitors based on aqueous liquid electrolytes that are produced by Hutchinson, this thesis has focused on the development of ionic gels composed of crosslinked polymers containing an ionic liquid phase, that can be used as electrolytes. So, the goal of this study has been to synthesize self-supported thin films (e = 100 µm) with high ionic conductivity.The first two synthesis strategies, respectively based on poly(1,2,3-triazolium)s networks and the crosslinking of polysiloxanes copolymers, did not lead to materials with satisfying properties for this application. So, a third synthesis pathway, based on the copolymerization of acrylate monomers in the presence of imidazolium ionic liquids was developed. As these ionogels were able to contain as much as 70 w% of this liquid phase, ionic conductivities of up to 10-3 S cm-1 at 30°C were obtained, while maintaining good mechanical stability at very low thickness. These electrolytes were characterized by electrochemical measures, and displayed the ability to function inside supercapacitive cells. However, low specific capacities were obtained, indicating that the electrodes’ porosity is only partially filled. Further work is necessary for the optimization of these ionogels, as well as the adaptation of the cells’ components, but these materials showed good potential nevertheless, as they allowed the preparation of functioning cells with the same dimensions as commercial devices