Thesis (Ed.D.)--Boston University

No description available.

Binary element-hydride systems have become a pertinent topic for high pressure research, following the measurement of record high temperature superconductivity in the dense hydrogen-sulfur system. The experimental study followed predictions of superconductivity with high transition temperature (Tc) in (H2S)2H2 at high pressures, leading to the current consensus that the high Tc phase is H3S, produced from the decomposition and recombination of H2S at high pressures. However, conjecture over the behaviour of hydrogen sulfide upon compression, and experimental limitations, cast significant ambiguity over interpretations of the structure and mechanism of the superconducting phase. Nonetheless, theory also predicts high Tc superconductivity in the dense hydrogen selenide and telenide systems; both experimentally uncharted at high pressures prior to this study. This thesis explores and maps the phase diagrams of hydrogen-chalcogen (S, Se, Te) systems using a combination of high pressure Raman spectroscopy and x-ray diffraction techniques. Gaining a comprehensive understanding of the behaviour of these systems under pressure is crucial to the eventual elucidation of the true nature of high Tc superconductivity. Hydrogen sulfide (H2S) and hydrogen selenide (H2Se) are appreciably toxic. A simple in situ synthesis technique is reported for producing hydrogen-chalcogenides directly from their constituent elements within diamond anvil cells, circumventing the need to condense toxic gases. This technique is also utilised to provide excess hydrogen, in order to produce the hydrogen-rich cocrystals thought to be vital to the formation of the high Tc phase. The hydrogen-sulfur system is most thoroughly investigated, and first presented. High quality Raman spectroscopic data provides an experimental review of pure H2S. Studies of (H2S)2H2 evaluate the current known ambient temperature phases and reveal three novel low temperature phases. Phase II0 is identified on cooling of phase I to 173 K (10 GPa), via splitting of both the single S-H stretching mode and low-frequency H2 vibron; sharp stretching modes indicate a significant reduction in orientational disorder. Successive splitting of the low-frequency H2 vibrons indicates two additional phase changes at 29 GPa (phase III0) and 53 GPa (phase- IV0) respectively, at 80 K. Phase IV0 is associated with an overall increase in symmetry. Evidence is also presented for a tentative fourth novel low temperature phase at ~160 GPa (20 K) and for the formation of an exceptionally stable hydrogen-sulfur compound with potentially novel stoichiometry. The behaviour of the H2S and (H2S)2H2 mixed molecular system is also reported; demonstrating that the coexistence of (H2S)2H2 and H2S can influence the hydrogen-bonding within both systems at high pressures. The first high pressure studies of the hydrogen-selenium system at ambient temperature are reported. The high pressure phase sequence of H2Se (I { I0 - IV) is identified by Raman spectroscopy, mirroring that of H2S. The isothermal boundaries for phases I0 and IV are found at 7 and 12 GPa respectively, at 300 K. Phase IV may have higher symmetry than phase IV H2S. X-ray diffraction and Raman spectroscopy demonstrate that the H2Se:H2 mixtures form cocrystals of (H2Se)2H2 from 4.2 GPa, with tetragonal space group I4=mcm, analogous to (H2S)2H2. Both H2Se and (H2Se)2H2 are shown to decompose into their constituent elements above 24 GPa. Attempts to synthesise the elusive H2Te directly from hydrogen and tellurium are reported. No reaction occurs upon heating Te in H2 at 0.2 GPa to 573 K. No visible reaction occurs between H2 and the high-pressure phases of Te, upon laser-heating. No photoreaction occurs upon exposure of tellurium in hydrogen to intense laser light (532 nm) at 0.2 GPa and 300 K, but formation may be stabilised at lower temperatures.

This study is an examination of the office of high priest from its beginning with Adam as the first and down through the restoration of the Church in the last days. This study revealed that the office of high priest was the only priesthood office that was held from the time of Adam until the Melchizedek Priesthood was taken, generally, away from the congregation of Israel in Moses' day. The office did however remain but was exclusive only to a few. Another important aspect of the history of the office of high priest that will be shown is how the doctrine of foreordination applies to the office. The Book of Mormon prophet Alma discourse on the subject will be analyzed and used to show many of the requirements men who have desired the office of high priest have and continue to meet. This study also details the restoration of the office of high priest in the dispensation of the fullness of times. The Doctrine and Covenants is scriptural backdrop of this section. Historical examples from journals and other writings of those who were there will show how the office has been understood in the Church since the days of Joseph Smith. Further, a detailed account of how the Church came to understand the office of high priest in regard to the Melchizedek Priesthood office of Seventy is set forth. Lastly, a brief examination of vicarious bestowal of the office of high priest and the future of the office of high priest is also given.

Cardiovascular disease remains the leading cause of mortality in the United States, and a primary educational objective is to develop professional competency among nurses to ensure the provision of safe and effective care to the cardiac patient. Benner's theory of novice-to-expert led to the development of an evidence-based scenario for the care of the patient with chest pain using risk-free high-fidelity simulation environments that focused on assessment, history taking, and communication, while evaluating improvements in the competency of nurses providing care to chest pain patients. Thirty-six nurses volunteered in the study. Feedback from nurse educators, which led to modifications to the scenario, preceptor evaluation of participants during simulation, and post simulation feedback of participants, were analyzed using an inductive and exploratory theme analysis. Participants reported they learned meaningful information but felt somewhat confused regarding the correct course of action when multiple events occurred simultaneously. Preceptors' feedback identified participant failure to meet stated scenario expectations. Quantitative analysis of data, using one sample t test, compared the pre- and post-test scores measuring participant knowledge on assessment, history taking, and communication. Although knowledge scores increased, the difference was not clinically significant based on the negative feedback from both preceptor and participants. Accurate appraisal of nurses' competency in assessment, history-taking, and communication skills is needed prior to exposure to simulation. Simulation scenarios may be more clinically significant when tailored to an individual participant's competency levels.

Thesis (Family Medicine)-- University of Limpopo, 2010. / Summary not available

No description available.

A magneto-optical apparatus has been designed to investigate flux and current distributions in various forms of high-temperature superconductor after the application of external magnetic fields, transport currents, and both in sequence. It is concluded that flux motion depends significantly on the superconductor characteristic flux pinning strength and geometry. The flux profiles at the surface of an isolated thin film strip, and thin films in x-array and shunted-x-array arrangements have been studied in detail. It has been found that the theoretical flux profile, characterised by a logarithmic singularity at its edges and a vertical slope at the flux front, become rounded when the sample thickness is taken into account. Experiment has confirmed that the current density reaches its critical value in the flux-penetrated region while there is a continuous non-zero current density in the central flux-free region. Also magnetic interactions exist between the strips. Band-shaped and dome-shaped flux distributions caused by geometrical barrier at different weak pinning strengths were observed in Bi2Sr2CaCu2O8+x single crystals between 20 K and 70 K. The geometrical barrier also governs the transport current leading to a square-shaped distribution near the crystal edges at 20 K. Cracks and defects in Bi-2223/Ag tapes were visualised without destruction of the tape. The inhomogeneous flux distribution indicated that defects, including cracks, in superconducting filaments limit the current-carrying capacity of the tape. In addition, at 70 K a fraction of the transport current has been found to flow in the silver sheath. An investigation of the influence of the twin planes on vortex motion in a YBa2Cu3O7-d single crystal has shown that after a twin barrier is initially overcome, the twin planes, regardless of their directions, act as an easy-flow channel for vortex penetration at low temperatures as the pinning strength in the twin planes is weaker than that in the untwinned region, whereas, they act as a barrier at high temperatures where the pinning strength in the twin planes is stronger. Furthermore, vortex penetration along the twin planes is a factor of four greater than that for the untwinned region at 25 K.

Currently in Vietnam there is an increasing demand for building and housing. Many high-rise housing developments have been built recently and continue to be constructed. This dissertation will not address the question of whether the high-rises should be built or not, it will focus on the question: What is appropriate high-rise housing in Vietnam?

"March 2003" / Corrections inside front cover. / Includes bibliographical references (leaves 111-167) / x, 167 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 2003