• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 25
  • 9
  • 5
  • 4
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 51
  • 27
  • 19
  • 17
  • 12
  • 11
  • 9
  • 9
  • 8
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 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.
11

The application of new generation batteries in old tactical radios / D. de Villiers

De Villiers, Daniel January 2007 (has links)
The power requirement for the soldier's equipment is largely supplied by batteries. Situational awareness is critical for a soldier to perform his tasks. Therefore the radio used by the soldier is a key element in situational awareness and also consumes the most power. The South African National Defence Force (SANDF) uses the A43 tactical radio specifically designed for them. The radios are regarded as old technology but will be in use for about another five years. The radios still use non-rechargeable alkaline batteries which do not last very long and are not cost effective. The purpose of this study is to research the new generation secondary batteries as a possible replacement for the alkaline battery packs. The new generation batteries investigated in this study are the latest rechargeable batteries, also called secondary batteries. They include nickel cadmium, nickel metal hydride, lithium ion, rechargeable alkaline manganese and zinc air. The main features of rechargeable cells are covered and the cell characteristics are defined to allow the technology to be matched to the user requirement. Li-ion technology was found to be the best choice. This research also showed that international trends in battery usage are towards Li-ion. A new Li-ion battery was designed based on commercial cells. Tests showed that commercial Li-ion cells can be used in the radio and that they outperform the current battery by far. The study also examined the design of a New Generation Battery System consisting of an intelligent battery, a charger which uses a Systems Management Bus and a battery 'state of health" analyser to assist the user to maintain the batteries. Tests were done to demonstrate that the battery can withstand typical military environmental conditions. Expected military missions for a battery system were defined and used to compare the cost between the existing batteries and the new batteries system. Important usage factors which will influence the client when using a New Generation Battery System were addressed. To summarise, this study showed that by using a New Generation Battery System, the SANDF could relieve the operational cost of the A43 radio while saving on weight and enabling the soldier to carry out longer missions. / Thesis (M.Ing. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2008.
12

The application of new generation batteries in old tactical radios / D. de Villiers

De Villiers, Daniel January 2007 (has links)
The power requirement for the soldier's equipment is largely supplied by batteries. Situational awareness is critical for a soldier to perform his tasks. Therefore the radio used by the soldier is a key element in situational awareness and also consumes the most power. The South African National Defence Force (SANDF) uses the A43 tactical radio specifically designed for them. The radios are regarded as old technology but will be in use for about another five years. The radios still use non-rechargeable alkaline batteries which do not last very long and are not cost effective. The purpose of this study is to research the new generation secondary batteries as a possible replacement for the alkaline battery packs. The new generation batteries investigated in this study are the latest rechargeable batteries, also called secondary batteries. They include nickel cadmium, nickel metal hydride, lithium ion, rechargeable alkaline manganese and zinc air. The main features of rechargeable cells are covered and the cell characteristics are defined to allow the technology to be matched to the user requirement. Li-ion technology was found to be the best choice. This research also showed that international trends in battery usage are towards Li-ion. A new Li-ion battery was designed based on commercial cells. Tests showed that commercial Li-ion cells can be used in the radio and that they outperform the current battery by far. The study also examined the design of a New Generation Battery System consisting of an intelligent battery, a charger which uses a Systems Management Bus and a battery 'state of health" analyser to assist the user to maintain the batteries. Tests were done to demonstrate that the battery can withstand typical military environmental conditions. Expected military missions for a battery system were defined and used to compare the cost between the existing batteries and the new batteries system. Important usage factors which will influence the client when using a New Generation Battery System were addressed. To summarise, this study showed that by using a New Generation Battery System, the SANDF could relieve the operational cost of the A43 radio while saving on weight and enabling the soldier to carry out longer missions. / Thesis (M.Ing. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2008.
13

Operation reengineering in a medium-sized plant /

Tsang, Chi-fai, Ringo. January 1995 (has links)
Thesis (M.B.A.)--University of Hong Kong, 1995. / "31 December 1993." Includes bibliographical references.
14

Smart renewable energy : architectures, dimensioning and monitoring

Erasmus, Zenville January 2017 (has links)
>Magister Scientiae - MSc / The Smart Renewable Energy project at the University of The Western Cape, under the guidance of the Intelligent Systems and Advanced Telecommunication (ISAT) group, aims at developing a dynamic system that enables users to (1) design smart architectures for next generation wind and solar systems to meet African power challenges (2) use these architectures to dimension the underlying solar and wind power systems and (3) simulate, implement and evaluate the performance of such power systems. The project's existing web and mobile monitoring system will undergo a much needed upgrade to cater for monitoring of the existing system's environmental and battery bank parameters. This will be implemented by allowing users to monitor input, storage and output trends over various time frames. These time frames would include hourly, daily, weekly and monthly readings. The visual evaluation of the system will be generated by mathematical, statistical and machine learning techniques. Trends will be discovered that will allow users to optimize the system's efficiency and their usage patterns. The accompanied dimensioning system will allow users to cater for their needs in a two way fashion. Users will be able to specify the number of devices that they want to run from a solar or wind based system and their power needs will be generated. They will also be able to determine what a given system is capable of producing and the number of devices that can be used simultaneously, as a result. / National Research Foundation (NRF) and Namibia Students Financial Assistance Fund (NSFAF)
15

Návrh strategie v oblasti elektromobility v ČR pro konkrétní společnost / Proposal of electromobility strategy in the Czech republic for concrete company

Šlechta, Martin January 2011 (has links)
The subject of the thesis is to identify and assess the current status of electromobility in the Czech Republic and proposal of partly strategiy and recommendations for company Mercedes-Benz Czech Republic s.r.o. in this area. The theoretical part deals with the definition of the theory of strategic management process, especially the analysis of the external and internal area and methodologies of creation strategy. The practical part describes the characteristics of the Mercedes-Benz Czech Republic s.r.o., direct analysis of the electromobility and internal analysis of the company. Finally, there is a summary SWOT analysis and strategy formulation and recommendations in the area of electromobility for the company.
16

Computational modelling studies of lithiated TiO2 nano-architectured structures at different temperatures, for energy storage applications

Rikhotso, Blessing Nkateko January 2019 (has links)
Thesis (M. Sc. (Chemistry)) -- University of Limpopo, 2019 / Nano-architecture structures of LixTiO2 are very promising as anode materials for lithium rechargeable batteries due to their ability to accommodate more lithium atoms and its ability to withstand high temperatures at atomistic level through charging and discharging. In these studies, we investigated how nano-architectured structures of LixTiO2 behave at high temperatures through the process of amorphisation and recrystallisation. A computational method of molecular dynamics (MD) simulation was employed to recrystallise the amorphous LixTiO2 nano-architectures of bulk, nanosheet, nanoporous and nanosphere, where x depicts the fraction of lithium ions, i.e. 0.03, 0.04 and 0.07. The main objective of this study was to go beyond the previous inserted lithium atoms on TiO2 and understand the effects of concentrations, temperature, defect chemistry and charge storage properties/capacity on the overall lithium transport to improve lithium ion battery performance. Recrystallisation of all four nanostructures from amorphous precursors were successfully achieved and was followed by the cooling process towards 0 K and finally we heated all four nano-architectures at temperature intervals of 100 K up to 500 K. The variation of configuration energies as a function of time, was used to monitor the crystal growth of all nanostructures. Calculated Ti-O radial distribution function, were used to confirm the stability interaction after cooling. Calculated X-Ray Diffraction (XRD) spectra where used to characterise and compare their patterns at cooled and above high temperatures, using the model nanostructures, and they showed polymorphic nanostructures with LixTiO2 domains of both rutile and brookite in accord with experiment. Amorphisation and recrystallization showed good results in generating complex microstructures. In particular, bulk structures show few zigzag tunnels (indicative of micro twinning) with 0.03 Li but 0.04 Li and 0.07 Li show complex v patterns indicating a highly defected structure. While 0.03 and 0.04Li nanospheres show, zigzag and straight tunnels in accord with experiment, the one with 0.07 Li has melted. Lastly, nanoporous and nanosheet structures have pure straight and zigzag patterns that are well in accord with our XRD patterns at all concentrations of lithium atoms and temperatures. The lithium transport was analysed using diffusion coefficient, calculated as a function of temperature in order to confirm the mobility above the given temperatures. An increase in temperature shows an increase in diffusivity of lithium at all lithium concentrations in nanoporous and nanosheet structures. The same trend was observed in bulk but only with 0.03 and 0.07 Li ion concentrations. / National Research Foundation (NRF)
17

A Numerical Study of Solid Oxide Iron-Air Battery:Thermodynamic Analysis and Heat and Mass Transfer Characteristics / 固体酸化物形鉄空気蓄電池の数値解析-熱力学的解析および熱物質移動特性-

Ohmori, Hiroko 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19703号 / 工博第4158号 / 新制||工||1641(附属図書館) / 32739 / 京都大学大学院工学研究科航空宇宙工学専攻 / (主査)教授 吉田 英生, 准教授 岩井 裕, 教授 鈴木 基史, 教授 江口 浩一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
18

Design principles of the cathode materials for multivalent cation batteries / 多価陽イオン二次電池における正極材料の開発と設計指針

Mori, Takuya 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第19817号 / 人博第788号 / 新制||人||189(附属図書館) / 27||人博||788(吉田南総合図書館) / 32853 / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 内本 喜晴, 教授 田部 勢津久, 教授 吉田 寿雄 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM
19

Studies on Bifunctional Oxygen Electrocatalysts with Perovskite Structures / ペロブスカイト構造を有する二機能性空気極触媒に関する研究

Miyahara, Yuto 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20397号 / 工博第4334号 / 新制||工||1672(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 作花 哲夫, 教授 陰山 洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
20

Elucidation of Anode Reaction of Magnesium Rechargeable Batteries by operando Soft X-ray Absorption Spectroscopy / オペランド軟X線吸収分光法を用いたマグネシウム二次電池負極反応機構の解明

Hattori, Masashi 26 November 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第21433号 / 人博第871号 / 2018||人博||871(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 内本 喜晴, 教授 吉田 寿雄, 准教授 戸﨑 充男 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

Page generated in 0.1701 seconds