Köln, Universiẗat, Diss., 2001.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.

Yes

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Rapid setup and verification of 4 automatic tracking antennas, 2 radio frequency switch matrixes, 32 telemetry receivers with 16 diversity combiners, an intermediate frequency switch matrix and the signal distribution equipment interface to the analog and digital fiber optic relay systems was required. This paper provides sample displays of the station status window, telemetry receiver and test parameter dialog boxes, mission event log window and test result windows for bit error rate, noise power ratio, solar calibration and antenna servo tests. Use of the software is apparent from sample displays so the text concentrates on lessons learned from site surveys, verification of configuration against mission files, accommodation of change of plug-in modules (e.g., IF filters in the telemetry receiver), tolerance of equipment removed from the system for maintenance, built-in test of serial and parallel communications and modular software design for replacement of equipment.

Univ. der Künste, Diss.--Berlin, 2003.

none

This thesis offers two layers of analysis of a contemporary dance titled Watch The Gap, a site-inspired work initiated by the architecture, design, and function of the Jamaica, Queens (New York) train station. For the dance analysis, the investigated question is: can a dance that is inspired by a specific location but performed on a concert stage still fit within the genre of site-dance? By comparing its choreographic methodologies within the field of site-dance, a second investigated question arises: can these practices be codified and taught as part of a course in a university setting? Through this study I examine, explain, and analyze the different choreographic tools and aspects of site-dance impacting the field of dance by a comparison study with Watch The Gap and a pedagogical investigation into improvisation and site-dance. In doing so, pedagogical applications, key terminology, and methods, discussed in the paper, help to clarify and add to the discussion of this rapidly growing art form. / text

Metal oxide materials are a broad class of materials found in many current technologies due to their interesting properties such as magnetism and ferroelectricity. Material properties can be tuned and heavily influenced by disorder at the atomic level, as has been shown in the ferrimagnetic and ferroelectric Al2-x-yGaxFeyO3 materials, which adopt the non-centrosymmetric, orthorhombic GaFeO3 crystal structure-type (Pna21). The significant cation disorder and non centrosymmetric nature of the crystal structure underlie the multiferroic properties in these materials and make them one of the few chemical systems to possess multiferroic ordering near room temperature. Unfortunately, while cation site disorder is responsible for the multiferroic properties observed in these compounds, their complex crystal structure has led to inconsistent reports in the ternary Al2-xFexO3 and Ga2-xFexO3 compounds. X-ray absorption near-edge spectroscopy (XANES) is an element specific technique, which can be used to examine cation site disorder as a function of changes in the average coordination environment around the metal, providing a means of studying these complex materials. In this thesis, XANES was used to investigate factors affecting cation site disorder in a series of Al1-xGaxFeO3 materials (0 ≤ x ≤ 1) adopting the GaFeO3 crystal structure-type. The GaFeO3 crystal structure has four cation sites, of which, the distorted octahedral Fe1 and Fe2 sites are primarily occupied by Fe3+, and the less distorted tetrahedral A1 and octahedral A2 sites are primarily occupied by Al3+ or Ga3+. These materials were initially synthesized using a high temperature ceramic method, and it was found that with increasing Ga3+ content (x) these materials show a decrease in the amount of cation site disorder between the tetrahedral site and the three octahedral sites. This decrease is attributed to the tetrahedral site preference of Ga3+, which inhibits cation site disorder at the A1 site, as opposed to the octahedral site preference observed for Al3+. Additionally, Fe3+ was found to predominantly occupy the three octahedral sites over the tetrahedral site in these materials, likely because of its large ionic size and the strong magnetic coupling between those three sites. The quaternary Al1-xGaxFeO3 materials (0 ≤ x ≤ 1) were synthesized again via two other techniques: a citrate sol-gel method and a co-precipitation method. The oxide network binding the binary metal oxide precursors limits ion mobility in the high temperature ceramic method. The citrate sol-gel and co-precipitation methods were used to generate mixed-metal precursors with a more homogeneous distribution of the metal cations than the binary metal oxide precursors commonly used by the high temperature ceramic method. Mixed-metal precursors reduce the distance the ions have to diffuse, while the nature of the amorphous matrix was found to affect disorder in the resulting material. From analysis of the XANES spectra, the ceramic method showed the least amount of cation site disorder, followed by the citrate sol-gel method and co-precipitation method, respectively. Greater annealing temperatures resulted in an increase in cation site disorder, with the average coordination number of Al3+ and Ga3+ increasing while the average coordination number of Fe3+ decreased. Al1-xGaxFeO3 materials synthesized via the co-precipitation method showed the greatest amount of cation disorder, followed by the citrate sol-gel and high temperature ceramic techniques, respectively. The research presented in this thesis is among the first to examine a large number of materials from the relatively unexplored Al1-xGaxFeO3 system, and has contributed to the growing body of knowledge on the factors affecting cation site disorder in these materials and potentially other systems. Further, despite a simple rationale for understanding the features present in Al L2,3- and Ga K-edge spectra, these studies have shown how effectively XANES can be used to understand subtle changes in the atomic structure of solid-state materials.

The Anthropological Papers of the University of Arizona is a peer-reviewed monograph series sponsored by the School of Anthropology. Established in 1959, the series publishes archaeological and ethnographic papers that use contemporary method and theory to investigate problems of anthropological importance in the southwestern United States, Mexico, and related areas.

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