Analyses for the Production and Dosimetry of Adding Uranium-232 as a Tracer to the Uranium Fuel Cycle

This dissertation is an examination of the use of uranium-232 as a tracer in nuclear fuel. Decay daughters from 232U, particularly thallium-208, produce high energy gamma rays that, when added to uranium, may increase detectability in case of theft or diversion, but are also hazardous in high quantities. Previous studies of the 232U decay chain are examined. This work will go in to a dosimetry study to determine how hazardous varying levels of 232U are, and how to efficiently produce 232U in sufficient quantities. A dosimetry study was performed to determine the dose hazards due to the addition of 232U to uranium. This dosimetry study determined that the concentration of 232U to add to uranium is between 100 parts per trillion. A production scoping study was performed to determine the preferred target materials for producing 232U via neutron irradiations. Calculations performed using SCALE 6.2 ORIGEN determined that 231Pa and 230Th are the optimum target materials, and that reactor irradiations are preferred. ORIGEN Calculations using flux spectra from the High Flux Isotope Reactor determined that 231Pa calculations that the optimum irradiation time is 2 HFIR cycles, yielding 0.35 grams of 232U per gram 231Pa. Thorium-230 irradiations yielded 0.15 grams 232U per gram 230Th after five cycles. Neutronics analyses examined the neutron spectra in targets modeled in MCNP, and determined that self-shielding is a concern that may reduce yield, especially in 230Th, lowering the yield to 0.1 grams after five cycles. A study of 238Pu contaminated with 236Pu produced at the Advanced Test Reactor was also conducted base on work from the CSNR. This examined strategies for mitigating against 236Pu contamination by chemical removal of 232U. Only material irradiated close to the center of the ATR needed this extra processing, and only a few micrograms of 232U is recoverable. However, these small quantities may still have a use for small stockpiles or testing purposes

Fuel burnup simulation and analysis of the Missouri S&T Reactor

The purpose of this work is to simulate the fuel burnup of the Missouri S&T Reactor. This work was accomplished using the Monte Carlo software MCNP. The primary core configurations of MSTR were modeled and the power history was used to determine the input parameters for the burnup simulation. These simulations were run to determine the burnup for each fuel element used in the core of MSTR. With these simulations, the new predicted isotopic compositions were added into the model. New core configurations were determined, and the burnup corrected model was used to predict the excess reactivity and control rod worth of the three shim rods in the new configurations labeled 125 and 126. The reactor core was arranged to these configurations in order to determine excess reactivity and control rod worth for the shim rods. When core 125 was tested, the reactor could not attain criticality without external source, which was predicted by the simulations. Core 126 had sufficient excess criticality to support measurement. Those measurements had inconsistent results, and indicated methodology errors. Based on this work, it is recommended to revise the code for temperature gradients and Doppler effects. The experimental methodology for the rod drop tests should also be revised to ensure the methods are applicable to core parameters. These corrections allow the model and the reactor itself to better reflect each other so that the predictions by MCNP will better reflect the measurements at MSTR --Abstract, page iii

Development of a Rooftop Collaborative Experimental Space through Experiential Learning Projects

The Solar, Water, Energy, and Thermal Laboratory (SWEAT Lab) is a rooftop experimental space at the University of Texas at Austin built by graduate and undergraduate students in the Cockrell School of Engineering. The project was funded by the Texas State Energy Conservation Office and the University’s Green Fee Grant, a competitive grant program funded by UT Austin tuition fees to support sustainability-related projects and initiatives on campus. The SWEAT Lab is an on-going experiential learning facility that enables engineering education by deploying energy and water-related projects. To date, the lab contains a full weather station tracking weather data, a rainwater harvesting system and rooftop garden. This project presented many opportunities for students to learn first hand about unique engineering challenges. The lab is located on the roof of the 10 story Engineering Teaching Center (ETC) building, so students had to design and build systems with constraints such as weight limitations and wind resistance. Students also gained experience working with building facilities and management for structural additions, power, and internet connection for instruments. With the Bird’s eye view of UT Austin campus, this unique laboratory offers a new perspective and dimension to applied student research projects at UT Austin.Cockrell School of Engineerin

LONDRES (Reino Unido). Palacio de Kensington. Palacios. 1764 (1762). 1:1600

Dedicatoría : "To His most Excellent Majesty George the III D. King of Gret Britain &c"Escalas gráficas de dos estadios [= 24,7 cm] y 20 "Chains" [= 25,2 cm]. Orientado con lis en rosa de ocho vientosOrografía por normalesRelacion de las principales edificaciones y lugares indicados por clave numéricaTítulo, dedicatoría, autor y escalas en cartelas barrocas acompañadas de escenas alegóricasForma parte de la Colección Mendoz

Conservative and Surgical Management of Unilateral and Bilateral Internuclear Ophthalmoplegia (INO)—A Retrospective Analysis

Aim: To report the outcomes of the natural progression and ophthalmic treatment of patients reviewed in a tertiary hospital trust with unilateral or bilateral internuclear ophthalmoplegia. Method: A retrospective case note analysis was performed and 33 patients diagnosed with unilateral or bilateral internuclear ophthalmoplegia (INO) were identified. The diagnosis, aetiology, presence of diplopia, ophthalmic management options and progression were recorded and analysed. This included both conservative and surgical management. Results: The most common aetiologies of INO within this cohort were stroke/ischaemic (69.7%) and multiple sclerosis (MS) (30.3%). Unilateral INO was more prevalent than bilateral INO, with 20 cases (60.6%) compared to 13 cases (39.4%), respectively. A higher proportion of unilateral INO were attributed to stroke (90%) whilst a higher proportion of bilateral INO were attributed to MS (61.5%). The most prescribed management at primary assessment was occlusion (45.5%) and prisms (24.2%). Some patients required no orthoptic intervention (30.3%). Two patients had surgical management of strabismus secondary to bilateral INO. Conclusion: Occlusion was the most common form of management for symptomatic relief of diplopia. Patients who presented at the first visit with no symptoms were unlikely to need any orthoptic intervention. Of the two patients who went on to require surgical intervention, restoration of binocular single vision (BSV) was achieved post-operatively with the use of a Fresnel prism. However, the differences in both surgical technique and number of surgeries required make this difficult to generalise. Additional research is needed to further explore the surgical management of INO

Optimal timing for power plant maintenance in the Electricity Reliability Council of Texas in a changing climate

We analyzed data for the Electricity Reliability Council of Texas (ERCOT) to assess shoulder seasons -- that is, the 45 days of lowest total energy use and peak demand in the spring and fall -- and whether their occurrence has changed over time. Over the period 1996--2022, the shoulder seasons never started earlier than late March nor later than mid-October, corresponding well with the minimum of total degree days. In the temperature record 1959--2022, the minimum in degree days in the spring moved earlier, from early March to early February, and in the fall moved later, from early to mid-November. Warming temperatures might cause these minima in degree days to merge into a single annual minimum in December or January by the mid-2040s, a time when there is a non-trivial risk of 1-day record energy use and peak demand from winter storms

Magnitude of placebo response in clinical trials of paroxetine for vasomotor symptoms: a meta-analysis

IntroductionVasomotor symptoms, or hot flashes, are among the most common complaints for menopausal and postmenopausal women. As an alternative to hormone replacement therapy, paroxetine mesylate became the only non-hormonal treatment approved by the U.S. Food and Drug Administration (FDA), despite limited evidence for its efficacy. More specifically, there is uncertainty around paroxetine's unique benefit and the magnitude of the placebo response in clinical trials of paroxetine.MethodsRelevant databases were searched to identify randomized clinical trials examining the efficacy of paroxetine to treat hot flashes. The primary outcomes of interest were hot flash frequency and hot flash severity scores. Data was extracted from the published results, and risk of bias assessments were conducted.ResultsSix randomized clinical trials that included a total of 1,486 women were coded and analyzed. The results demonstrated that 79% of the mean treatment response for hot flash frequency is accounted for by a placebo response, resulting in a mean true drug effect of 21% at most. Additionally, 68% of the mean treatment response for hot flash severity is accounted for by a placebo response, resulting in a maximum true drug effect of 32%.DiscussionThe results herein call into question the actual efficacy of the only FDA approved, non-hormonal treatment for hot flashes by demonstrating that a placebo response accounts for the majority of treatment responses for reductions in both hot flash frequency and severity. The findings provide evidence to reevaluate the use of paroxetine to treat postmenopausal hot flashes and emphasize the importance of considering effective, alternative treatments for vasomotor symptoms

Utilising Virtual Clinics and Orthoptists to Aid COVID-19 Service Recovery in Adult Strabismus

Background: The Sheffield Virtual Adult Strabismus service was already well established and was put to real-time trial during the COVID-19 pandemic. We describe a multi-disciplinary adaptation to offer a safe and effective service delivery. We evaluate the efficacy of a virtual strabismus service during the pandemic to meet clinical demand, streamline patient care, balance care delivery and optimise medical input. Methods: Prospective data analysis from the virtual strabismus clinics dated from January 2015 to November 2021. All information was captured at first consultation with comprehensive specialist Orthoptic assessment and imaging; then reviewed by a strabismus consultant for clinical outcome. Management was discussed virtually with patients by the consultant. Results: Pre-COVID (January 2015–March 2020), 1,068 appointments were offered. During COVID (July 2020–November 2021), 442 appointments were offered. Clinical capacity increased to meet demand. Within two months of service re-opening, first appointment mean waiting time reduced below 18 weeks. During COVID, 24.6% of patients were listed for procedures after first visit. Face-to-face medical follow up for non-surgical cases reduced from 47.7% to 16.3%. Conclusion: Virtual strabismus services offer flexible, safe and effective ways to meet fluctuating referral patterns and maximise limited time and resources. Orthoptists are uniquely essential and highly valued keyworkers to conservatively manage non-surgical strabismus. Utilising the skillsets of Allied Health Professionals (AHPs) across the NHS is crucial to sustain ongoing clinical demand and patient care