Psychedelics are currently being researched due to their long-lasting antidepressant, anxiolytic and neuroplasticity inducing actions. The mechanism by which they induce these effects remains poorly understood. Here, we decided to investigate a relatively unexplored possibility. A potential interaction of psilocybin administration and sleep and their combined effects on memory consolidation. Memory formation in animals and humans is greatly influenced by sleep manipulation which led us to assess the possibility with spatial memory tasks. We hypothesized that acute psilocybin administration after learning may have a beneficial influence on memory consolidation in rats. To determine whether an interaction with sleep exists we also subjected the rats to combinations of psilocybin and control vehicle with normal sleep and sleep deprivation. Our data did not suggest such an interaction exists. Secondly, we tried to find out if psilocybin and sleep manipulation leads to changes in neuroplasticity-related events. A process that could very likely be the basis of such a proposed beneficial effect. For this purpose, we analysed the expression of the immediate-early gene Arc and the immature neuron marker doublecortin in the rat hippocampus. Doublecortin's expression was not influenced by any of the factors....

Various geotechnical-related energy applications, such as geothermal piles, subject soils to temperature changes. Recorded temperature variations around thermo-active infrastructure and within the active layer of the permafrost reveal the cyclic and transient nature of these temperature changes. Previous studies on the thermo-mechanical behavior of soils did not consider the effect of the temperature change rate on such behavior. Since it is widely accepted nowadays that soil behavior is rate-dependent, evaluating soil behavior under more realistic, transient temperature changes is crucial. In this dissertation, a method to calibrate triaxial cells used to expose soil samples to transient thermal loads is developed. This calibration is critical to ensure reliable thermally induced pore water pressure measurements and estimates of thermally induced volumetric strains of tested specimens. Then, thermally induced water flow and pore pressure generation under partial drainage conditions are formulated to account for the effect of temperature change rate on the thermal consolidation of cohesive soils. The formulation is performed by coupling Darcy's law for water flow in porous media with existing relations estimating thermally induced fully-drained volumetric strains. The resulting partial differential equation—the thermal consolidation theory—is solved and validated against experimental results that used the calibration from the first task. Using this newly developed theory, it was found that temperature-dependent properties of the pore water and the soil's hydraulic conductivity have a significant role in thermal consolidation. Lastly, a microstructural analysis is performed to assess the evolution of the microstructure of a normally consolidated clay under a full thermal cycle consisting of a freezing (F), thawing (T), heating (H), and cooling (C) thermal path. This microstructural investigation aims to explain the observed macroscale responses of cohesive soils under such a thermal path. After each step along the considered thermal path, the microstructure evolution was assessed using measurements of the specific surface area and pore size distribution. In the end, the variations of specific surface areas and pore size distributions were used to explain the macro-scale thermo-mechanical behavior of cohesive soils. / Doctor of Philosophy / Temperature can impact the properties of the soil, such as strength and stiffness. Besides the alterations in the strength, temperature change can cause volume change in the ground. In cold regions such as Alaska, the soil is frozen all year (i.e., permafrost) or experiences freezing-thawing cycles throughout the year. Freezing strengthens the soil but causes expansion of its volume, destroying infrastructures, including roads, runways, and buildings. Also, geothermal energy applications that utilize the ground as a heat exchanger medium may increase or decrease the surrounding soil temperature. Increasing the ground temperature changes the strength of the soil and also causes settlements. Climate change is also aggravating the situation. The temperature rises due to climate change alters the temperature pattern worldwide. Furthermore, global warming exposes frozen grounds to longer thawing stages at higher temperatures, deteriorating the permafrost. Consequently, such thermal cycles make cold regions' infrastructures susceptible to damage. Measurements of the temperature variations in the ground show that they are cyclic in nature, with different rates, maximums, and minimums. Therefore, it is essential to study the thermal behavior of soils under cyclic thermal loads. For this purpose, a new method for accurately measuring soils' response to more realistic temperature changes is developed in this dissertation. Then a model is developed to predict thermally induced volume changes and water pressures that account for the rate of temperature change. The model is then used for a sensitivity analysis to study the most important parameters controlling the deformation induced by temperature changes. It was found that variations of pore water properties with temperature and the ability of the soil to retain or drain water are the two most critical parameters that control thermally induced deformation in soils. Finally, the microstructure evolution of cohesive soils with temperature is also investigated to explain the observed alterations in soil behavior with temperature. This microstructural assessment suggests that the microstructure of soils reacts to temperature by changing the pore size distribution, shape, and number of pores.

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The dissertation explores the determinants of the choice between friendly mergers and hostile tender offers as alternative acquisition methods in the market for corporate control. The theoretical model focuses on the target management's firm specific human capital as a primary determinant of the choice. The model predicts that firm characteristics like low insider holdings and high debt, indicating the presence of incumbent management's firm specific human capital, increase the likelihood of a friendly merger as opposed to a hostile tender offer. Other firm characteristics that influence the choice of acquisition method emerge from Jensen's (1986) free cash flow theory. The empirical testing of the hypotheses uses state-based sampling and conditional maximum likelihood estimation of logit models. The results provide strong evidence in support of the theoretical model developed in the dissertation and Jensen’s free cash flow theory. / Ph. D.

The purpose of this study was to present an analysis for predicting the magnitude and rate of settlement and the magnitude of the pore water pressure during consolidation of linear elastic soils by using the finite element method. The formulation of the method is based on a variational principle. The numerical characteristics of the method for one- and two-dimensional problems in plane strain were examined and the results were presented in graphical form to illustrate the effect of mesh refinement. Other factors examined in 2-D problems were the effect on the results of Poisson's ratio v, the relative distance to the boundary, and the time increment. For multilayered soil systems a parametric study was made. The effects of wide variations in material properties on the consolidation process and general criteria for reliable results using the FE formulation were derived o A three-layered system was used for the parametric study on the material parameters. The method was applied to four layer field problem and the results were found to be reasonable. Permeability and strength anisotropy and their effect on the rate of consolidation were examined for a homogeneous soil under a strip footing. / Master of Science

Channeling has already been an observed phenomenon that often occurs during settling and sedimentation processes of finer materials. However, it has been regarded as a minor factor affecting settling process, e.g. settling velocity or consolidation rate. In this study, settling behaviors of talcs, kaolins and attapulgite were reviewed by experiments with small and large settling columns with special focus on channel formation during sedimentation. The large settling column is equipped with twenty eight measuring points, which are connected to pressure transducers for measuring pore pressure changes during settling. Throughout the study, channel formation was observed and related to the experimental conditions affecting it. The excess pore pressure changes were measured during the large column tests. Channels occurred under flocculation in zone settling and also in consolidation zones; pressure drop was observed near channels in some cases. It was apparent that channels work as a facilitator to dissipate the excess pore water pressure. It is summarized that not only initial concentration but also the material properties, such as specific gravity and shape of particles, can affect the channel formation. / Master of Science

The Tamakoshi Dam in Nepal experienced 19 cm of settlement due to three earthquakes that took place from December 14, 2014 to May 12, 2015. This settlement caused massive damage and halted construction and was believed to have been caused by seismic compression. Seismic compression is the accrual of contractive volumetric strain in sandy soils during earthquake shaking for cases where the generated excess pore water pressures are low. The purpose of this case study is to investigate the settlements of the dam intake block relative to the right abutment block of the dam during the three earthquakes. Towards this end, soil profiles for the dam were developed from the boring logs and suites of ground motions were selected and scaled to be representative of the shaking at the base of the dam for the two of the three earthquakes which were well documented. Equivalent linear analysis was completed for the suites of ground motions to produce shear strain time histories which were then utilized in the Jiang et al. (2020) proposed procedure for seismic compression prediction. The results were found to not align with the settlement that was observed in the field, so post-liquefaction consolidation was also considered to be a possible cause of the settlement. The results from that analysis also showed that consideration of post-liquefaction consolidation did not yield settlements representative of those observed in the field. More detailed studies are recommended to assess the settlements that were observed at the dam site, particularly analyses that take into account below and above grade topographic effects on the ground motions and settlements at the ground surface. / Master of Science / The Tamakoshi Dam in Nepal experienced 19 cm of settlement due to three earthquakes that took place from December 14, 2014 to May 12, 2015. This settlement caused massive damage and halted construction and was believed to have been caused by seismic compression. Seismic compression is the accrual of contractive volumetric strain in sandy soils during earthquake shaking for cases where the generated excess pore water pressures are low. The purpose of this case study is to investigate the settlements of the dam intake block relative to the right abutment block of the dam during the three earthquakes. Representative soil profiles were developed based on data collected from the site for analysis of the settlement. Two approaches were used to compute predicted settlement, one which considered only seismic compression as the cause of settlement and a hybrid method that considered both seismic compression and post-liquefaction consolidation. Both approaches predicted settlement values that were less than what was observed in the field. It was found that the ground motion prediction equations used in the analysis were not representative of the tectonic setting in Nepal and thus was the main reason for the under-prediction. The relevance of this research lies in using methodology developed in academia to analyze a real world event and draw conclusions about the methodology's applicability.

Thermoplastic composite filament winding is an on-line consolidation process, where the composite experiences a complex temperature history and undergoes a number of temperature history affected microstructural changes that influence the structure's subsequent properties. These changes include melting, crystallization, void formation, degradation and consolidation. In the present study, models of the thermoplastic filament winding process were developed to identify and understand the relationships between process variables and the structure quality. These include models that describe the heat transfer, consolidation and crystallization processes that occur during fabrication of a filament wound composites structure. A comprehensive thermal model of the thermoplastic filament winding process was developed to calculate the temperature profiles in the composite substrate and the towpreg temperature before entering the nippoint. A two-dimensional finite element heat transfer analysis for the composite-mandrel assembly was formulated in the polar coordinate system, which facilitates the description of the geometry and the boundary conditions. A four-node 'sector element' was used to describe the domain of interest. Sector elements were selected to give a better representation of the curved boundary shape which should improve accuracy with fewer elements compared to a finite element solution in the Cartesian-coordinate system. Hence the computational cost will be reduced. The second thermal analysis was a two-dimensional, Cartesian coordinate, finite element model of the towpreg as it enters the nippoint. The results show that the calculated temperature distribution in the composite substrate compared well with temperature data measured during winding and consolidation. The analysis also agrees with the experimental observation that the melt region is formed on the surface of the incoming towpreg in the nippoint and not on the substrate. Incorporated with the heat transfer analysis were the consolidation and crystallization models. These models were used to calculate the degree of interply bonding and the crystallinity achieved during composite manufacture. Bonding and crystallinity developments during the winding process were investigated using the model. It is concluded that lower winding speed, higher hot-air heater nozzle temperature, and higher substrate preheating temperature yield higher nippoint temperature, better consolidation and a higher degree of crystallization. Complete consolidation and higher matrix crystallization will result in higher interlaminar strength of the wound composite structure. / Master of Science

Yes / The effect of compaction pressure on subsequent soil behaviour during isotropic consolidation has been investigated by conducting controlled-suction triaxial tests on samples of an unsaturated compacted silty soil. A comprehensive set of laboratory experiments was carried out in a double-walled triaxial apparatus on samples of unsaturated soil that were prepared using two different compaction pressures. The axis translation technique was used for creating the desired suctions in the samples. In the experiments, the soil samples were subjected to isotropic consolidation under constant suctions. The results show that different compaction pressures produce different fabrics in a soil and therefore affect the behaviour of the soil. The results also show that the value of yield stress and the location of the loading¿collapse (LC) yield curve are functions of soil fabric. Furthermore, it is shown that the slopes of normal consolidation lines for densely and loosely compacted samples differ in unsaturated conditions but are the same in saturated soils. A comparison is made between the behaviour of the dense and loose samples, and the difference in the behaviour is explained.