Food habits of the Uinta ground squirrel were investigated on some open meadows on the south-east slope of Mt. Timpanogos. Special emphasis was placed on species of plants eaten; and preference of plants in relation to season, succulence, and phenology. Other investigations were made in reference to: parts of plants eaten, non-plant material eaten, daily and seasonal activities in relation to foraging, feeding procedures, and the relationship between plant cover and Uinta ground squirrel activity.

<p> This work is concerned with the calculation by means of many-particle perturbation theory of the lowest order corrections to the Random Phase Approximation (RPA) description of an interacting electron gas in its ground state. Expressions in terms of the dynamically screened coulomb interaction are obtained for the electron proper self-energy, the electron momentum distribution function, and the screening function. Techniques, which reduce computational labour to a manageable level, are developed for the practical evaluation of the required corrections. The numerical results are not conclusive but they indicate that when all corrections of the same order (in the screened interaction) are included, the expansion converges sufficiently rapidly that the results are valid in the range of metallic densities.</p> / Thesis / Doctor of Philosophy (PhD)

<P> Single crystals of Zn2P207 containing 0.1% by weight of manganese impurity or 0.04% by weight of copper impurity were studied by means of electron spin resonance techniques from room temperature up to about 200°c. </p> <P> The existence of a phase transition at about 132°C in Zn2P2O7 was confirmed and a new phase, existing between 132°C and 155°C was found. The space group of the unit cell in this phase was deduced from the esr measurements. The spin Hamiltonian parameters were measured in the three phases and a discussion of their significance in terms of current theories of the zero field splitting of the ground state of S-state ionsis given. </p> / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.

In this thesis, a support vector machine (SVM) is used to develop a model to predict Arias Intensity. Arias Intensity is a measure of the strength of ground motions that considers both the amplitude and the duration of ground motions. In this research, a subset of the database from the “Next Generation and the duration of Ground-Motion Attenuation Models” project was used as the training data. The data includes 3525 ground motion records from 175 earthquakes. This research provides the assessment of historical earthquakes using arias intensity data. Support vector machine uses a Kernel function to transform the data into a high dimensional space where relationships between the variables can be efficiently described using simpler models. In this research, after testing several kernel functions, a Gaussian Kernel was selected for the predictive model. The resulting model uses magnitude, epicentral distance, and the shear wave velocity as the predictor of Arias Intensity.

<p> An energy gap or "pseudogap", where there is spin pairing without phase coherence, has been observed in a number of unconventional superconductors that has been detected even above the superconducting transition. It has been proposed that this "pseudogap" region is intimately related to the appearance of high Tc superconductivity. Comparable spin gaps have been observed in a number of low dimensional quantum spin systems with a spin-singlet ground state. Therefore quantum magnets which show collective singlet ground states have been receiving much interest recently. </p> <p> As an example of these; CuGe03 is one of the few quasi-one dimensional magnetic insulators which displays a Spin-Peierls transition. This novel transition results from the coupling of the lattice with S=l/2 spin degrees of freedom to break transitional symmetry below some characteristic phase transition temperature, and a collective singlet magnetic ground state with a characteristic energy gap is observed. </p> <p> In my thesis I have studied the critical phenomena associated with the SpinPeierls transition which occurs in the inorganic compound Cul-xCdxGe03by means of Xray Scattering. I also conducted inelastic neutron scattering experiments and studied the temperature dependence of the singlet-triplet excitation of this system. I applied different theoretical methods to determine the best model describing the behavior observed for this material and compared the results with those obtained on the pure compound. </p> <p> There are few quasi two dimensional experimental examples of interacting dimers such as SrCu2(B03)2 which has been proposed as a realization of the Shastry-Sutherland model. This system has been modeled as Heisenberg spins in a square lattice with two exchange coupling constants of magnitudes J and J' along the diagonal and the edges of the lattice. Its ground state is known to be a collective singlet state. It is known theoretically that its ground state changes from a gapped singlet to a gapless antiferromagnetic state as a function of J/J'. Recently, subleading terms in the Hamiltonian have been considered, such as Dzyaloshinski-Moriya interactions, which are needed to understand the precise physical properties of this material. </p> <p> I performed high resolution, inelastic neutron scattering measurements on this material aim at clarifying the nature of the singlet-triplet excitation spectrum. The results revealed the dispersion relations along with the Q-dependence of the excitations. Finally, neutron powder diffraction measurements were also performed in order to investigate any possible structural phase transition in this material. </p> / Thesis / Master of Science (MSc)

No description available.

Remedial ground densification is commonly used to reduce the liquefaction susceptibility of loose, saturated sand deposits, wherein controlled liquefaction is typically induced as the first step in the densification process. Assuming that the extent of induced liquefaction is approximately equal to the extent of ground densification, the purpose of this research is to assess the feasibility of using earthquake liquefaction data in remedial ground densification design via energy-based concepts. The energy dissipated by frictional mechanisms during the relative movement of sand grains is hypothesized to be directly related to the ability of a soil to resist liquefaction (i.e., Capacity). This hypothesis is supported by energy-based pore pressure generation models, which functionally relate dissipated energy to residual excess pore pressures. Assuming a linearized hysteretic model, a "simplified" expression is derived for computing the energy dissipated in the soil during an earthquake (i.e., Demand). Using this expression, the cumulative energy dissipated per unit volume of soil and normalized by the initial mean effective confining stress (i.e., normalized energy demand: NED) is calculated for 126 earthquake case histories for which the occurrence or non-occurrence of liquefaction is known. By plotting the computed NED values as a function of their corresponding SPT penetration resistance, a correlation between the normalized energy capacity of the soil (NEC) and SPT penetration resistance is established by the boundary giving a reasonable separation of the liquefaction / no liquefaction data points. NEC is the cumulative energy dissipated per unit volume of soil up to initial liquefaction, normalized by the initial mean effective confining stress, and the NEC correlation with SPT penetration resistance is referred to as the Capacity curve. Because the motions induced during earthquake shaking and remedial ground densification significantly differ in amplitude, duration, and frequency content, the dependency of the derived Capacity curve on the nature of the loading needs to be established. Towards this end, the calibration parameters for energy-based pore pressure generation models are examined for their dependence on the amplitude of the applied loading. The premise being that if the relationship between dissipated energy and pore pressure generation is independent of the amplitude of loading, then the energy required to generate excess pore pressures equal to the initial effective confining stress should also be independent of the load amplitude. However, no conclusive statement could be made from results of this review. Next, first order numerical models are developed for computing the spatial distribution of the energy dissipated in the soil during treatment using the vibratory probe method, deep dynamic compaction, and explosive compaction. In conjunction with the earthquake-derived Capacity curves, the models are used to predict the spatial extent of induced liquefaction during soil treatment and compared with the predicted spatial extent of improvement using empirical expressions and guidelines. Although the proposed numerical models require further validation, the predicted extent of liquefaction and improvement are in very good agreement, thus giving credence to the feasibility of using the Capacity curve for remedial ground densification design. Although further work is required to develop energy-based remedial densification design procedures, the potential benefits of such procedures are as follows. By using the Capacity curve, the minimum dissipated energy required for successful treatment of the soil can be determined. Because there are physical limits on the magnitude of the energy that can be imparted by a given technique, such an approach may lead to improved feasibility assessments and initial designs of the densification programs. / Ph. D.

A multidisciplinary design optimization (MDO) methodology is developed to link the aerodynamic shape design to the system costs for magnetically levitated (MAGLEV) vehicles. These railed vehicles can cruise at speeds approaching that of short haul aircraft and travel just inches from a guideway. They are slated for high speed intercity service of up to 500 miles in length and would compete with air shuttle services. The realization of this technology hinges upon economic viability which is the impetus for the design methodology presented here. This methodology involves models for the aerodynamics, structural weight, direct operating cost, acquisition cost, and life cycle cost and utilizes the DOT optimization software. Optimizations are performed using sequential quadratic programming for a 5 design variable problem. This problem is reformulated using 7 design variables to overcome problems due to non-smooth design space. The reformulation of the problem provides a smoother design space which is navigable by calculus based optimizers. The MDO methodology proves to be a useful tool for the design of MAGLEV vehicles. The optimizations show significant and sensible differences between designing for minimum life cycle cost and other figures of merit. The optimizations also show a need for a more sensitive acquisition cost model which is not based simply on weight engineering. As a part of the design methodology, a low-order aerodynamics model is developed for the prediction of 2-D, ground effect flow over bluff bodies. The model employs a continuous vortex sheet to model the solid surface, discrete vortices to model the shed wake, the Stratford Criterion to determine the location of the turbulent separation, and the vorticity conservation condition to determine the strength of the shed vorticity. The continuous vortex sheet better matches the mechanics of the flow than discrete singularities and therefore better predicts the ground effect flow. The predictions compare well with higher-order computational methods and experimental data. A 3-D extension to this model is investigated, although no 3-D design optimizations are performed. NOTE: An updated copy of this ETD was added on 05/29/2013. / Ph. D.