This thesis proposes a novel consolidated approach for substantial compaction of HVDC lines that includes both new tower geometries as well as novel control concepts. This is based on a thorough discussion on the basic overhead line design parameters and their impact on the right of way width and tower height. Then the electrical aspects of the new approach such as dc overvoltage assessment and lightning performance are investigated. The required horizontal clearances between pole conductors and tower members, as a component of the right of way width, depend on the maximum expected overvoltages. Detailed electromagnetic transient models for the point to point MMC HVDC with different transmission configurations, all including the proposed dc overhead line, are developed for this thesis. The models are used to assess fault contingencies that result in the most significant overvoltage stresses on the HVDC transmission line for finding minimum air clearances and for the design of overvoltage limiting devices, such as surge arresters. New control approaches are proposed that significantly reduce the dc side overvoltage and consequently minimize the required air clearances for maximum compaction of the HVDC overhead lines and also reduce the required surge arrester size for line insulation. Because power transmission lines are the most exposed component within a power system, they are subject to lightning strikes which, in turn, are the main cause of disruption to power flows. This thesis will include an analysis of lightning occurrence on the proposed compact transmission line in order to assess the risk of pole faults. The focus of this analysis is mainly on evaluation of the critical lightning currents that cause fast front overvoltage stresses that may result in insulation failure. / May 2017

The purpose of this paper is to investigate some properties of compact topological spaces and to relate these concepts to the separation properties.

In the recent years around the world there has been a constant increase in the number of students who apply to continue their studies at a higher level, this in turn has brought a great demand in the occupation for student housing. Finding a place to live is one of the issues that new students have to face when moving into another city or country, which can be really challenging at times. The project speculates with a design concept that may help the demands for student housing in the city of Växjö, Sweden. The idea is a housing unit for one person that occupies a space of 13 m2 with an interior space of 10 m2 so it can be moved with a truck to the place where required for a temporary time. The interior proposes an efficient, flexible and comfortable space for the needs in the everyday life of a student. This is done with an organize layout and some multi-purpose furniture that can also be retractable when not in use to save space.

by Li Chong, Victor Kun Wa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 99-101). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.iii / ACKNOWLEDGEMENT --- p.v / TABLE OF CONTENTS --- p.vii / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- CD Manufacturing Technology --- p.1 / Chapter 1.1.1 --- Electroforming --- p.2 / Chapter 1.1.2 --- Computer Numerical Control (CNC) --- p.2 / Chapter 1.1.3 --- Photolithography --- p.4 / Chapter 1.1.4 --- Laser --- p.5 / Chapter 1.2 --- Research Objective --- p.6 / Chapter 1.3 --- Thesis Outline --- p.6 / Chapter 2 --- Conversion Software (AutoGEN) --- p.9 / Chapter 2.1 --- Computer-Aided Design --- p.9 / Chapter 2.2 --- AutoCAD Programming --- p.10 / Chapter 2.3 --- AutoCAD Development System (ADS) --- p.11 / Chapter 2.4 --- AutoCAD Runtime Extension (ARX) --- p.12 / Chapter 2.5 --- AutoLISP Programming --- p.12 / Chapter 2.5.1 --- Advantages of AutoLISP --- p.13 / Chapter 2.6 --- Caltech Intermediate Format (CIF) --- p.14 / Chapter 2.6.1 --- Structure of CIF Format --- p.15 / Chapter 2.7 --- Architecture of Conversion Software --- p.15 / Chapter 2.7.1 --- Stage 1 - AutoGEN (DLTM) Module --- p.16 / Chapter 2.7.2 --- Stage 2 - AutoGEN (DCRM) Module --- p.17 / Chapter 2.8 --- DLTM Input Screen --- p.17 / Chapter 2.9 --- DCRM Data Screen --- p.18 / Chapter 2.10 --- Conversion from 2D to 3D --- p.18 / Chapter 2.11 --- AutoGEN - Geometric Primitive --- p.19 / Chapter 2.12 --- AutoGEN - Geometric Transformation --- p.19 / Chapter 2.13 --- Conversion of Simplified and Complex Drawings --- p.22 / Chapter 3 --- Manufacturing Process --- p.24 / Chapter 3.1 --- Stamper Manufacturing --- p.25 / Chapter 3.2 --- CD Manufacturing --- p.30 / Chapter 3.3 --- Internal Stress of Deposit in Electroforming --- p.34 / Chapter 4 --- CNC Approach --- p.37 / Chapter 4.1 --- Computer-Aided Manufacturing --- p.37 / Chapter 4.2 --- CNC Machining --- p.37 / Chapter 4.2.1 --- Experiment --- p.39 / Chapter 4.3 --- Advantages of CNC Approach --- p.42 / Chapter 4.4 --- Limitations of CNC Approach --- p.42 / Chapter 4.5 --- CNC and Effects of Heat Generated --- p.43 / Chapter 5 --- Photolithography Approach --- p.45 / Chapter 5.1 --- Experiment --- p.47 / Chapter 5.2 --- Channel Analysis --- p.49 / Chapter 6 --- Laser Approach --- p.53 / Chapter 6.1 --- Dual Beam Laser Machine --- p.53 / Chapter 6.2 --- Creation of Pits and Lands --- p.54 / Chapter 6.2.1 --- Experiment --- p.54 / Chapter 6.3 --- Creation of Continuous Channel --- p.56 / Chapter 6.4 --- Procedure of Channel Creation (NA set at a fixed constant) --- p.57 / Chapter 6.4.1 --- Experiment 1 --- p.59 / Chapter 6.4.2 --- Experiment 2 --- p.60 / Chapter 6.4.3 --- Experiment 3 --- p.61 / Chapter 6.5 --- Procedure of Channel Creation (ILV set at a fixed constant) --- p.62 / Chapter 6.5.1 --- Experiment 1 --- p.63 / Chapter 6.5.2 --- Experiment 2 --- p.64 / Chapter 6.5.3 --- Experiment 3 --- p.66 / Chapter 7 --- Photolithography Approach (Enhancement) --- p.68 / Chapter 7.1 --- Creation of High-Aspect-Ratio Channel --- p.68 / Chapter 7.1.1 --- Experiment 1 --- p.76 / Chapter 7.1.2 --- Experiment 2 --- p.80 / Chapter 8 --- Conclusion and Future Proposal --- p.83 / Chapter 8.1 --- Conclusion --- p.83 / Chapter 8.2 --- Future Proposal --- p.86 / APPENDIX --- p.89 / Chapter A.1 --- Additional Information on CNC Approach --- p.88 / Chapter A.2 --- Channel Dimension of Design Mask --- p.89 / Chapter A.3 --- Additional Information on Photolithography Approach --- p.94 / Chapter A.4 --- Additional Information on Laser Approach --- p.95 / BIBLIOGRAPHY --- p.98

Chan, Pak On = 星體震動的分析方法 / 陳柏安. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 117-119). / Abstracts in English and Chinese. / Chan, Pak On = Xing ti zhen dong de fen xi fang fa / Chen Boan. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Outline of the Content --- p.3 / Chapter 2 --- Preliminaries --- p.5 / Chapter 2.1 --- Einstein Equation --- p.5 / Chapter 2.1.1 --- Hydrostatic Equilibrium --- p.6 / Chapter 2.1.2 --- Linearized Stellar Pulsation --- p.7 / Chapter 2.1.3 --- Gravitational Radiation --- p.11 / Chapter 2.2 --- Classification of Modes --- p.13 / Chapter 2.2.1 --- Fundamental Mode --- p.14 / Chapter 2.2.2 --- Pressure Modes --- p.14 / Chapter 2.2.3 --- Gravity Modes --- p.14 / Chapter 2.3 --- Relativistic Cowling Approximation --- p.15 / Chapter 3 --- Stellar Structure of Quark Stars --- p.19 / Chapter 3.1 --- Ordinary Quark Stars --- p.19 / Chapter 3.1.1 --- Stellar Profile --- p.20 / Chapter 3.1.2 --- Radius and Mass --- p.27 / Chapter 3.1.3 --- Moment of Inertia --- p.30 / Chapter 3.2 --- Effects of Finite Strange Quark Mass and Finite Temperature --- p.32 / Chapter 3.2.1 --- Sommerfeld's Expansions --- p.33 / Chapter 3.2.2 --- Static EOS for Quark Matter --- p.35 / Chapter 3.2.3 --- Corrections to Ordinary Quark Stars --- p.37 / Chapter 3.2.4 --- Induced Buoyancy under Adiabaticity --- p.40 / Chapter 3.2.5 --- Induced Buoyancy under Fixed Composition --- p.45 / Chapter 3.3 --- Addition of Nuclear Crust --- p.47 / Chapter 4 --- Pressure Modes --- p.52 / Chapter 4.1 --- Sturm-Liouville Equation for p-modes --- p.52 / Chapter 4.2 --- Asymptotic Expansion --- p.54 / Chapter 4.3 --- "P""modes for Quark Stars" --- p.57 / Chapter 4.4 --- p-modes for Neutron Stars --- p.62 / Chapter 4.5 --- p-modes for Hybrid Stars --- p.65 / Chapter 5 --- Gravity Modes --- p.74 / Chapter 5.1 --- Sturm-Liouville Equation for modes --- p.74 / Chapter 5.2 --- Asymptotic Expansion --- p.76 / Chapter 5.3 --- g-modes for Quark Stars --- p.78 / Chapter 5.4 --- modes for Hybrid Stars --- p.83 / Chapter 5.5 --- Conditions on the modes --- p.88 / Chapter 6 --- Fundamental Mode --- p.93 / Chapter 6.1 --- Overview of the f-mode Universalities --- p.93 / Chapter 6.2 --- Relation between Real Part and Imaginary Part of Mwf --- p.95 / Chapter 6.3 --- New Universalities of f-mode --- p.96 / Chapter 7 --- Conclusions and Remarks --- p.104 / Chapter A --- Scattering Approximation --- p.106 / Chapter B --- Series Solution to Stellar Profile of Quark Stars --- p.108 / Chapter C --- AAKAS Formalism under Cowling Approximation --- p.113 / Chapter D --- Series Solutions to the Spectra of p-modes and g-modes --- p.114 / Bibliography --- p.117

Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish. In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although iii optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa. This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.

Central fuelling is a fundamental issue in the neat generation tokamak ITER (International Thermonuclear Experimental Reactor). It is essential for optimization of the bootstrap current which is proportional to the pressure gradient of trapped particles. The conventional tokamak fuelling techniques, such as gas puffing and cryogenic pellet injection, are considered to be inadequate to fulfill this goal due to premature ionization caused by high plasma temperature and density. Fuelling by injecting a compact torus (CT) may be the only viable method suitable for a reactor-grade tokamak. CTs can be injected at different angles with respect to the tokamak toroidal magnetic field, either horizontally or vertically. In vertical injection, deeper CT penetration is expected due to the absence of the gradient of tokamak toroidal magnetic field in that direction. This thesis contributes to experimental investigation of vertical compact torus injection into the STOR-M tokamak. <p>To perform vertical injection, the original injector- USCTI (University of Saskatchewan Compact Torus Injector) was modified by attaching a segment of 90˚ curved drift tube to bend the CT trajectory from horizontal to vertical. Bench tests have shown that a CT injected horizontally can be deflected effectively to the vertical direction. The velocity of 130 kms^{-1}has been achieved while the CT passes through the 90˚ curved drift tube. It was found that the CT magnetic field structure kept intact as a typical structure of compact torus plasma. By further optimization of the USCTI configuration, the velocity has been increased to 270 kms^{-1}. Based on the encouraging bench test results, actual vertical CT injection experiments have been performed in the STOR-M tokamak. Experimental results demonstrated, for the first time, vertical CT injection into a tokamak. Prompt increases both in line averaged electron density and in soft X-ray emission (central cord) are observed following vertical injection. Some H-mode phenomena, characterized by suppression of the m =2 Mirnov oscillation level and drop in Hα radiation level, have also been observed following the vertical injection. Fuelling effects caused by vertical injection and by tangential injection are discussed. The experimental results suggest that vertical CT injection is a feasible tokamak fuelling technique.

Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish. In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although iii optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa. This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.

Central fuelling is a fundamental issue in the neat generation tokamak ITER (International Thermonuclear Experimental Reactor). It is essential for optimization of the bootstrap current which is proportional to the pressure gradient of trapped particles. The conventional tokamak fuelling techniques, such as gas puffing and cryogenic pellet injection, are considered to be inadequate to fulfill this goal due to premature ionization caused by high plasma temperature and density. Fuelling by injecting a compact torus (CT) may be the only viable method suitable for a reactor-grade tokamak. CTs can be injected at different angles with respect to the tokamak toroidal magnetic field, either horizontally or vertically. In vertical injection, deeper CT penetration is expected due to the absence of the gradient of tokamak toroidal magnetic field in that direction. This thesis contributes to experimental investigation of vertical compact torus injection into the STOR-M tokamak. <p>To perform vertical injection, the original injector- USCTI (University of Saskatchewan Compact Torus Injector) was modified by attaching a segment of 90˚ curved drift tube to bend the CT trajectory from horizontal to vertical. Bench tests have shown that a CT injected horizontally can be deflected effectively to the vertical direction. The velocity of 130 kms^{-1}has been achieved while the CT passes through the 90˚ curved drift tube. It was found that the CT magnetic field structure kept intact as a typical structure of compact torus plasma. By further optimization of the USCTI configuration, the velocity has been increased to 270 kms^{-1}. Based on the encouraging bench test results, actual vertical CT injection experiments have been performed in the STOR-M tokamak. Experimental results demonstrated, for the first time, vertical CT injection into a tokamak. Prompt increases both in line averaged electron density and in soft X-ray emission (central cord) are observed following vertical injection. Some H-mode phenomena, characterized by suppression of the m =2 Mirnov oscillation level and drop in Hα radiation level, have also been observed following the vertical injection. Fuelling effects caused by vertical injection and by tangential injection are discussed. The experimental results suggest that vertical CT injection is a feasible tokamak fuelling technique.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 184-196). Also available on the Internet.