This thesis sets out to derive an analytical model for a center of gravity (CG) measuring platform and examines its validity through experimental testing and Finite Element Modeling. The method uses a two-stage platform tilting process to first locate the planar CG coordinates and then find the third CG coordinate normal to the platform. An uncertainty model of the measuring platform was also developed, both CG and uncertainty models were implemented in the form of a MATLAB code. A load cell sizing task was also added to the code to assist the Integration Engineers at Jet Propulsion Laboratory in selecting load cells to design their own version of the CG Platform. The constructed CG Platform for this project used an array of six strain gauges, four C2A-06-062LT-120 Tee Rosettes and two C2A-06-031WW-120 Stacked Rosettes. They were bonded onto the legs of three truss shaped bipods. Results from the Platform Tilting Tests could not be used to validate the CG model as the measured CG and weight values found from the experimental tests contained a considerable amount of error. The errors in the Platform Tilting Tests are believed to stem from the initial errors observed during the bipod rod and strain gauge calibration tests. As an alternative, an FE model of the CG measuring platform was created as another means of validation. The math model of the CG measuring platform was successfully validated by showing that there was less than a 0.01% different between the bipod loads predicted from the MATLAB code and the FE model. Using the FEM generated loads as inputs into the CG code to calculate a CG matched the initial point mass or CG created in the FE model within a 0.01% difference. To validate the CG model even further, another test should be performed using a CG Platform prototype instrumented with load cells to generate new experimental data and compare them with the results from the FE model.

The information presented in the thesis is a continuation of the Spacecraft Trajectory Optimization Suite (STOpS). This suite was originally designed and developed by Timothy Fitzgerald and further developed by Shane Sheehan, both graduate students at California Polytechnic State University, San Luis Obispo. Spacecraft utilizing low-thrust transfers are becoming more and more common due to their efficiency on interplanetary trajectories, and as such, finding the most optimal trajectory between two planets is something of interest. The version of STOpS presented in this thesis uses Multiple Gravity-Assist Low-Thrust (MGALT) trajectories paired with the island model paradigm to accomplish this goal. The island model utilizes four different global search algorithms: a Genetic Algorithm, Differential Evolution, Particle Swarm Optimization, and Monotonic Basin Hopping. The first three algorithms were featured in the initial version of STOpS written by Fitzgerald [1], and were subsequently modified by Sheehan [2] to work with a low-thrust adaptation of STOpS. For this work, Monotonic Basin Hopping was added to aid the suite with the MGALT trajectory search. Monotonic Basin Hopping was successfully validated against four different test functions which had been used to validate the other three algorithms. The purpose of this validation was to ensure Monotonic Basin Hopping would work as intended, ensuring it would work in cooperation with the other three algorithms to produce a near optimal solution. After verifying the addition of Monotonic Basin Hopping, all four algorithms were used in the island model paradigm to verify MGALT STOpS’ ability to solve two known orbital transfer problem. The first verification case involved an Earth to Mars transfer with fixed thruster parameters and a predetermined time of flight. The second verification case involved a transfer from Earth to Jupiter via a Mars gravity assist; two different versions of the verification case were solved against trajectories produced by industry optimization software, the Satellite Tour Design Program Low-Thrust Gravity Assist and the Gravity Assisted Low-thrust Local Optimization Program. In the first verification case, MGALT STOpS successfully validated the Earth to Mars trajectory problem and found results agreeable to literature. In the second verification case, MGALT STOpS was partially successful in validating the Earth to Mars to Jupiter trajectory problems, and found results similar to literature. The final software produced for this work is a trajectory optimization suite implemented in MATLAB, which can solve interplanetary low-thrust trajectories with or without the inclusion of gravity assists.

High gravity (HG) brewing has become the most used strategy for maximizing fermenter productivity in commercial brewing. While HG brewing has many benefits, the additional stress placed on the yeast due to the higher concentration of fermentable sugars in the wort can negatively impact fermentation performance and flavor compound formation. A proper dissolved oxygen (DO) level is vital to guarantee adequate yeast performance during HG fermentations. Dissolved oxygen is vital to yeast viability throughout the fermentation process, as yeast requires oxygen to synthesize vital cell membrane components needed for continued anaerobic growth and cell division. Previous research has demonstrated the importance of DO in wort for regular gravity fermentation and flavor compound production. However, the impact of dissolved oxygen during HG brewing on fermentation performance and how this will impact the production of flavor compounds have not been fully researched. The objectives of this research were to analyze the impact of wort aeration timing and concentration on fermentation performance, flavor stability, and the formation of volatile flavor compounds, determined using gas chromatography. Gas chromatography analysis was modeled after the ASBC Method Beer-48. Flavor stability and staling was analyzed during aging under normal and accelerated conditions utilizing TBA analysis. Pre-pitch oxygen treatments at levels greater than 8 ppm dissolved oxygen significantly increased attenuation when compared to the unoxygenated controls. Post-pitch oxygenation significantly increased attenuation, with DO treatments at levels of 8 ppm showed the most significant decrease in wort specific gravity. Aldehyde, ester, and higher alcohol production were all significantly affected by DO concentration. Aldehyde production decreased with increased DO concentration. Ester production increased from 0 to 8 ppm DO treatment and decreased at DO treatments greater than 8 ppm. Higher alcohol production increased from 0 to 10 ppm and decreased with DO treatments greater than 10 ppm. Greater concentrations v of DO resulted in greater TBA index values after normal and accelerated aging, with accelerated aging producing greater TBA index values than normal aging.

This study examines the determinants of internal migration in Spain. It pays close attention to a key variable that has been little studied so far, taxes. That is, we analyze whether the difference in taxes between the autonomous communities of Spain is a determining factor for Spanish citizens when deciding to move. In addition to taxes, other determinants such as GDP, geographical distance between regions, unemployment and amenities are also analysed. The study is based on the theory of Gravity model and Pooled OLS and fixed effects specifications are used. The findings reveal that the tax effort has a positive effect on migration, but its magnitude is small.

Exoskeletons are rapidly emerging from the realm of science-fiction myth to practical reality in everyday life. Various designs have provided viable means for individuals to regain capabilities that were lost or perform tasks not previously possible by their ability alone. In this research, I propose two novel exoskeletons for walking assistance and heavy load carriage. The first exoskeleton can be used to provide assistance for walking in various applications such as industrial productivity, rehabilitation, and military or space training. We introduce a design for a lower body wearable device that supports up to 80% of the user's body weight (667 N peak force) with a single actuator on each leg. Its underactuated design directs force through the user's center of mass with a single sprocket-chain driven prismatic actuator on each leg, allowing for natural gait and mobility. The device is optimized for simplicity, ease of assembly, low cost, and weight. The second design aims to counteract the one of the leading causes of injury in the workplace, repetitive and heavy lifting. The Heavy Lift and Carry Exoskeleton (HeavyLC Exo) is capable of safely lifting and carrying loads up to 36 kg (80 lbs) while minimizing the number of actuators to reduce weight and complexity. The HeavyLC Exo allows the user to direct the object, pause and hold the object steady mid-lift, and follow the natural kinematics of lifting. It is secured to the user with shoulder, chest, and dual thigh straps, along with an adjustable waist belt and overshoe attachment. Powered by two 14.8 V batteries and an off-board air compressor, the HeavyLC Exo has a total of 20 DOF, with 6 actuated DOF and 14 free DOF. The arms use only two actuators each, providing powered lifting and arm retraction/extension, and allowing a wide range of body postures; the legs are powered by single pneumatic actuators on each leg connected to the foot accompanied by a passive spring element to prevent excessive pelvic tilt and leg abduction during swing. The control system requires directional forces from the user at the tool handle of 19 N (4.3 lbf) on average. Current design limitations necessitate the user to provide up to 280 N (62.9 lbf) at the hip during worst load conditions, and future design optimization is proposed. A fully functional prototype of HeavyLC Exo is built, fully tested, and analyzed for improvement. / Master of Science / Exoskeletons, which were once only seen in science fiction, are now becoming a reality in everyday life. Various designs have made it possible for people to do things they couldn't do before or regain abilities they lost. In this research, two new exoskeletons are proposed - one for walking assistance and the other for carrying heavy loads. The first exoskeleton is designed to help people walk. It supports up to 80 % of the user's body weight with a single actuator on each leg, which directs force through the center of mass, allowing for natural gait and mobility. It's simple, easy to assemble, low-cost, and lightweight, making it useful in various applications such as medical rehabilitation, military or space training, and industrial productivity. The second exoskeleton is designed to help people lift and carry heavy objects, which is a common cause of workplace injuries. The Heavy Lift and Carry Exoskeleton (HeavyLC Exo) can safely lift and carry objects up to 36 kg (80 lbs) while minimizing the number of actuators to reduce weight and complexity. It's worn by the user using shoulder, chest, and dual thigh straps, along with an adjustable waist belt and overshoe attachment. The exoskeleton is powered by two batteries and an off-board air compressor, and has 20 degrees of freedom, with 6 powered and 14 non-powered, giving it significant flexibility to conform to lifting and walking motions allowing it to function with normal user range of motion. The arms use two actuators each to provide powered lifting and arm retraction/extension, while the legs are powered by single pneumatic actuators on each leg connected to the foot accompanied by a elastic spring element. The control system requires the user to lift and maneuver about 1.9 kg (4.2 lbs) to direct the object. A fully functional prototype has been built, tested, and analyzed for changes in the future.

The purpose of this study is to examine the effects on U.S. textile and apparel imports of the quantitative restrictions imposed under the Agreement on Textiles and Clothing (ATC) (1995-2005), the post-ATC U.S. safeguard quotas on 21 categories of Chinese textile and apparel products (2006-2008), and no quantitative restrictions on U.S. textile and apparel imports (2009-2010). Data were sourced from the Office of Textiles and Apparel (OTEXA) in the U.S. Department of Commerce, the GeoDist dataset from the Centre d'Etudes Prospectives et d'Informations Internationales (CEPII), and the United Nations Commodity Trade (U.N. Comtrade) database. In this research, three gravity equations were developed and estimated based on the existing gravity model. The first gravity equation was estimated to assess the effects of the independent variables commonly included in gravity models on the total value of U.S. textile and apparel imports from 187 exporting countries with a scaled dependent variable and from 177 without it. The result of the first gravity equation indicated that distance and the per capita GDPs of the exporting countries, exchange rates, and the total GDPs of the exporting countries are statistically significant and have the expected signs in the model with the scaled dependent variable. The second gravity equation was estimated to access the overall effect of the presence or absence of quotas and VERs on U.S. textile and apparel import quantity from the 187 exporting countries. The results from the second gravity model showed that the presence or absence of quotas or VERs is significant and has an unexpected positive sign because the United States tended to impose quotas and VERs on textile and apparel products that it imported in large amounts. The third gravity equation was estimated to assess trade creation and trade diversion effect of the quota and VER levels of U.S. textile and apparel imports with separate equations by product types considering the endogeneity by applying instrumental variables. The result from the third gravity equation showed that the quota and VER level is significant for fabric, apparel, and made-up products with expected signs but the variable is not significant for yarn products. These findings suggest that U.S. textile and apparel imports from the exporting countries limited by quotas and VERs on U.S. textile and apparel imports increased more than rest of world (ROW) imports from those countries as the quota and VER levels on U.S textile and apparel imports increased. Therefore, trade creation occurred between the United States and the exporting countries as the total SME quota or VER levels on those imports increased during the ATC and safeguard period. However, these findings show the demand of yarn as intermediates does not increase much in the United States; therefore, the increase of the total yarn quota or VER level has less of an effect on the yarn imports than other product types. / Ph. D.

This licentiate thesis in theoretical physics focuses on the existence of quantum features in physical systems such as axion dark matter and gravity. Our focus is mostly on effects which appear at low energies, a regime in which our models can be confronted with current experiments or within the foreseeable future. In our first project, we focus on squeezing of axion dark matter, a quantum mechanical effect which accompanies the standard mean field description of axions. We have showed that within a reasonable set of assumptions, the quantum state of axions is highly squeezed. This theoretical finding suggests that the mean field description of axion dark matter is incomplete, since the latter conceals many interesting and possibly experimentally relevant phenomena, and paves the way for axion dark matter studies beyond the mean field approximation. Moreover, in this thesis, some ongoing work on axion dark matter decoherence is presented. Our goal is to test whether axion dark matter squeezing is robust against decoherence. Preliminary results indicate that squeezing is not diminished in presence of environmental interactions. Our results stem from an interdisciplinary approach at the intersection between cosmology, quantum optics, quantum open systems and cold atoms. Our second work focuses on quantum features of gravity. An almost century old question is how gravity can be reconciled with the laws of quantum mechanics. This question remains still open and part of the reason is the lack of experimental evidence. However, in recent years, the rapid progress of experimental techniques allows for quantum control and manipulation of larger and larger quantum systems. These new experimental routes have sparkled an interest in testing such fundamental questions with tabletop experiments. One particularly interesting proposal aims to test whether gravity can mediate entanglement between two spatially superposed mesoscopic masses. This proposal, in order to deduce the existence of quantized gravitational mediators, relies on a quantum-information-theoretic argument, the so-called LOCC (Local Operations and Classical Communication). In our work, we critically assess this proposal, its underlying assumptions and what teaches about quantum gravity. We conclude that the LOCC argument is not useful and by invoking it, one cannot unambiguously infer the existence of quantum mediators unless the principle oflocality is elevated to a fundamental principle of nature. We support our claim by explicitly showing that well known relativistic field theories, apart from local formulations can also admit non-local ones. Therefore, the entanglement generating quantum channel can be either local or non-local.

<p>The chemical and physical properties of nine samples of sodalite have been determined along with the physical properties of an additional thirteen samples. Taken together with selected data from the literature these data indicate that: (1) the cell dimension of sodalite is constant for samples from one deposit within the limits ascribed to experimental error (± 0.0015 A° ) and the variation of a(0) for samples from other deposits is quite limited (i.e. ±0.005 A° ); (2) the specific gravity and refractive index exhibit small but measurable variations which cannot however be related to compositional variation; (3) the variation in chemical composition for sodalite indicated by analyses from the literature appears to be in error; much of the variation is attributed to zeolite impurities which were not removed from the samples before analysis; (4) probably all sodalites are represented to within 5 per cent by 6Na AlSiO(4).2NaCl with less than 0.30 weight per cent H(2)O.</p> <p>A petrographic study of the sodalite deposit at the Princess Quarry, Bancroft, Ontario, indicates that this mineral has formed from the reaction of chlorine-rich solutions with nepheline. The solutions appear to be derived from granite and syenite bodies which are regionally abundant in the vicinity of the Bancroft band of nepheline syenite gneiss. Many facts suggest that the present veins in the quarry have formed by the replacement of a pre-existing nepheline pegmatite.</p> / Thesis / Master of Science (MSc)

<p dir="ltr">The Cascadia margin in the Pacific Northwest of US is characterized by the subduction of the young and warm Juan De Fuca beneath the North American plate. This region shows strong correlations in spatial heterogeneities in geophysical observations such as thickness of low shear wave velocity zones in the lower crust, tremors distribution, intraslab seismicity, topography, uplift rates, and Bouguer gravity anomalies. In this thesis, both 3D and 2.5D forward gravity modeling have been conducted to understand the composition of the materials at ~20-40 km along the Cascadia subduction margin, that can explain the spatial heterogeneities by linking them together.</p>

Introduction: Space is an extreme environment exposing astronauts to microgravity and cosmic radiation resulting in immune dysfunction. To overcome the complex challenges of studying astronauts in space, bed rest studies represent an alternative model simulating microgravity exposure on Earth. We sought to characterize the steady state transcriptome changes in leukocytes isolated from two microgravity models: (1) participants to 60 days of bed rest and (2) astronauts to ~6 months of spaceflight. Methods: The bed rest study recruited twenty healthy men receiving a nutritional supplement or not; the spaceflight study had fourteen male and female astronauts participate. For both studies, ten blood samples were collected over three study phases, leukocytes were isolated, and transcriptomes were quantified using high throughput RNA-sequencing. My pipeline of data analysis applied differential expression (DE) methods and functional enrichment to identify gene expression changes and pathways responding to the altered gravity environments of both bed rest and spaceflight models. Results: Temporal differential expression identified transcriptome modulation reflecting multisystem shifts and immune dysregulation in response to the transitions to and from bed rest (2,415 DE genes) and spaceflight (247 DE genes). Interestingly, later bed rest and in-flight timepoints trended towards stable RNA levels with no differential expression. The bed rest study found the nutritional intervention had no mitigating effects on transcriptome changes (0 DE genes), and the spaceflight study revealed down-regulation in response to spaceflight followed by an opposite up-regulation upon return to Earth. Conclusion: The altered gravity environments of bed rest and spaceflight significantly modulated leukocyte transcriptome compositions revealing immune dysfunction at the molecular level. Future analyses utilizing the higher quality bed rest dataset is required to isolate the effect of microgravity from other space stressors and apply validation experiments to develop gene biomarkers indicative of immune deconditioning.