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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Tropical squall lines of the Arizona monsoon.

Smith, Walter Prestont. January 1989 (has links)
Squall lines possessing nearly all the characteristics of tropical squall lines occasionally develop during the summer monsoon over southern Arizona and northwestern Mexico. Initial thunderstorm formation is over the mountains along the Continental Divide in the late afternoon. Satellite imagery, cloud-to-ground lightning strike data, and surface observations indicate the squall lines move from east to west or northeast to southwest by discrete propagation faster than all the winds below 20 kPa so that most of the anvil clouds lag behind. The synoptic-scale circulation is anomalous with a strong ridge located over the western United States and a deep trough located over the eastern United States. West to northwest winds are found in the boundary layer over southern Arizona and northwest Mexico while a deep layer of east winds are observed above. As a result, most of the environmental wind shear is confined to the lowest 2.5 km above the ground. The low-level wind shear seems to be required for the westward propagation of thunderstorms and the formation of the squall lines. Extremely dry midtropospheric air develops in the easterly flow through some combination of advection and subsidence and also appears to be an important factor in the development of the squall lines. A two-dimensional, nonhydrostatic, numerical model was able to simulate many of the features observed in these squall lines. Solar heating of the elevated terrain in the model caused the initial thunderstorm to develop over the Continental Divide. Continued development of new thunderstorms to the west of the Divide produced a squall line that travelled westward by translation of cells and discrete propagation, wherein new cells would develop 10-25 km ahead of the old ones, at a speed greater than all the winds below 30 kPa. Upward motion produced by westward propagating gravity waves and by the strong low-level convergence found just ahead of the gust front appeared to cause several episodes of discrete propagation. The creation of horizontal potential temperature gradients and the vertical and horizontal advection of preexisting vorticity gradients combined to produce the vorticity field associated with the rear inflow jet that developed beneath the simulated squall line.
142

Assembly line balancing using hybrid genetic algorithms

Mapfaira, Herbert January 2002 (has links)
No description available.
143

Development of Si/SiGe technology for microwave integrated circuits

Ternent, Gary January 2000 (has links)
No description available.
144

Characterisation of the endoplasmic reticulum stress proteins GRP78 and GRP94 and their interaction with a recombinant antibody

Pearce, Alison January 2000 (has links)
No description available.
145

An investigation of low seed oil mutants of Arabidopsis thaliana

Minns, Gregory January 2001 (has links)
No description available.
146

Anti-tumour 2-(4-aminophenyl)benzothiazoles : structurally simple but exciting candidates for clinical trials

Chua, Mei-Sze January 1999 (has links)
No description available.
147

Exploration of Classic Confounders in Lymphoblastoid Cell Lines used to Study Select Antineoplastic Agents

Doetsch, Natalie, Harder-Ibarola, Kimberly, Sheth, Aliyah January 2010 (has links)
Class of 2012 Abstract / OBJECTIVES: Therapeutic response to chemotherapeutic agents in vitro can be studied using immortalized lymphoblastoid cell lines (LCLs). While LCLs provide a valuable model to study heritable factors and anticancer drug reponse in large populations, the results may be confounded by properties inherent to the model. This study is used to explore possible confounders in Choy et al.’s publicially available dataset (Accession#: GSE11582). METHODS: This study utilized Affymetrics U133A array gene expression and phenotypic data for 162 unrelated LCLs. SPSS was used for two-tailed bivariate Pearson correlation analysis comparing relative 6-mercaptopurine (6-MP), 5-fluorouracil (5-FU), and methotrexate sensitivities, growth rate and ATP levels. GeneSpring was used to compare the top and bottom quartiles of relative ATP levels using the unpaired T-test with a significance threshold of 0.001 and Benjamin-Hochberg FDR (n=82). RESULTS: It was found that relative sensitivities of 5-FU and 6-MP are significantly correlated (r2= 0.627, p<0.0001). Furthermore, it was determined that 5-FU sensitivity and growth rate and ATP levels are also correlated; however, no significant correlation was found between growth rate and ATP levles (r2=0.127, p=0.107). Relative ATP level was found to be a more significant determinant of 5-FU sensitivity than growth rate. GeneSpring analysis showed that 1500 genes are differentially regulated based on ATP levels. The gene ontology related to nucleic acid metabolism was overrepresented (p=1.425E-15). CONCLUSIONS: The results above suggest that growth rate and, to a greater extent, baseline ATP levels influence genetic expression of LCLs and may confound in vitro studies of antineoplastic agents.
148

Transmission line compaction using high phase order transmission

Bortnik, Jacob 17 August 2016 (has links)
A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering Degree awarded with distinction on 8 December I998 Johannesburg, 1998 / This report discusses high phase order (HPO) technology, i.e. the use of more than the conventional 3 phases for transmission of electric power, its use in the compaction of lines, and power density maximization over existing servitudes. It is structured in four parts. The first part introduces the concepts, establishes the need, and lists the advantages ofHPO. The second part deals with the technology itself and shows that it is possible to analyze HPO systems using symmetrical component analysis, lists common transformer configurations, covers protection, and so on. The third part analyses 5 case studies, the first 3 being analytical, and the last 2 being the first experimental test line, and the world's :first utility application ofHPO lines. The fmal section is a South African case study and compares an HPO line to an existing 400 kV 3-phase line and shows that the former is 87.5% more expensive to implement than the latter. Comparing the 3-phase and 6-phase lines on a more even basis, yielded a breakeven distance of225.86 km, above which the 6-phase option becomes more economical. These results are then explained and discussed in the conclusions section.
149

Spectral domain analysis of circular microstrip antennas on planar and spherical surfaces.

January 1990 (has links)
by Tam Wai Yip. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves [124]-[127] / ACKNOWLEDGEMENT --- p.i / LIST OF SYMBOLS --- p.ii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1-1 / Chapter CHAPTER 2 --- ANALYSIS OF MICROSTRIP ANTENNA ON A PLANAR SURFACE --- p.2-1 / Chapter 2.1 --- Dyadic Green's function formulation of a double-patch system --- p.2-3 / Chapter 2.1.1 --- Field components --- p.2-4 / Chapter 2.1.2 --- Boundary conditions and dyadic Green's function --- p.2-8 / Chapter 2.2 --- Microstrip antenna with an airgap --- p.2-14 / Chapter 2.3 --- Microstrip antenna with a superstate --- p.2-16 / Chapter 2.4 --- Galerkin's method --- p.2-18 / Chapter 2.5 --- Numerical computation --- p.2-25 / Chapter 2.6 --- Results and discussions --- p.2-30 / Chapter CHAPTER 3 --- ANALYSIS OF MICROSTRIP ANTENNA ON SPHERICAL SURFACE --- p.3-1 / Chapter 3.1 --- Fields in spherical coordinates --- p.3-3 / Chapter 3.1.1 --- solution of scalar Helmholtz equation in spherical coordinates --- p.3-3 / Chapter 3.1.2 --- Vector potentials --- p.3-6 / Chapter 3.2 --- Cavity model approach --- p.3-10 / Chapter 3.2.1 --- Formulation of radiation patterns --- p.3-11 / Chapter 3.2.2 --- Results and discussions --- p.3-23 / Chapter 3.3 --- Spectral domain approach --- p.3-39 / Chapter 3.3.1 --- General formulation --- p.3-39 / Chapter 3.3.2 --- Complex resonant frequency --- p.3-48 / Chapter 3.3.3 --- Far field radiation pattern --- p.3-51 / Chapter 3.3.4 --- Current distribution --- p.3-52 / Chapter 3.3.5 --- Limiting case of thin dielectric --- p.3-58 / Chapter 3.3.6 --- Results and discussions --- p.3-63 / Chapter CHAPTER 4 --- CONCLUSIONS --- p.4-1 / REFERENCES / Chapter APPENDIX I --- ASSOCIATED LEGENDRE FUNCTIONS / Chapter APPENDIX II --- SPHERICAL BESSEL FUNCTIONS / Chapter APPENDIX III --- VECTOR LEGENDRE SERIES / Chapter APPENDIX IV --- RESONANT FREQUENCY RELATION FOR THIN DIELECTRIC / Chapter APPENDIX V --- LIST OF PUBLICATIONS THAT ARE PRODUCED BY THE STUDIES
150

Tapered radio frequency transmission lines

Matarrese, Vincent D. 01 January 1992 (has links)
A transformation used to obtain solutions for the beam parameter equation of fiber optics is applied to the second order differential equation for nonuniform transmission lines. Methods are developed for deriving possible transmission line tapers from known solutions of the transformed equation. This study begins with a comprehensive overview of previous work done to obtain closed-form solutions for the transmission line equations. Limitations of the lumped parameter model are also discussed. As part of this thesis, a tapered transmission line is constructed, based on one of the solutions obtained from the fiber optics studies. A discussion of the design and measurement results are given in the final chapter.

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