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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.
1

Characterisation of nickel electrodes by electrochemical impedance spectroscopy

Barton, Raymond Terence January 1995 (has links)
The thesis describes an electrochemical investigation of different types of nickel electrode used in nickel-cadmium cells, which are available commercially or currently under development. Impedance spectroscopy has been used to determine the electrochemical characteristics of these electrodes. The electrochemistry of the nickel electrodes was modelled by the electrical analogue method. Allowance was made within the model for porosity and adsorption effects. Component values were initially estimated by graphical techniques and the computer fitting procedure was then completed by an iterative process to provide kinetic parameters which were used to compare and contrast the characteristics of the nickel sintered, pocket and plastic bonded electrodes. The technological target of this work was establish a possible method by which the residual capacity remaining within nickel-cadmium cells could be determined. The kinetic parameters generated by the electrical analogue technique have provided data on which to base a measurement for the prediction of the state of charge in nickel-cadmium cells.
2

Eco battery exchange system /

Kasetsuwan, Rit. January 1992 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1992. / Typescript. Includes bibliographical references (leaf 41).
3

The chemical speciation of copper, nickel, cadmiun and zinc in the South San Francisco Bay a multi-method approach /

Lao, Kathy Ann. January 1992 (has links)
Thesis (M.S.)--University of California, Santa Cruz, 1992. / Typescript. Includes bibliographical references (leaves 48-51).
4

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.
5

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.
6

Removal of Cu (II), Ni (II), Cd (II) and Pb (II) of wastewater of electroplating industry using hybrid system adsorption electro-flotation-coagulation / RemoÃÃo de Cu(II), Ni(II), Cd(II) E Pb(II) de efluentes de indÃstrias de galvanoplastia usando o sistema hÃbrido adsorÃÃo-eletro-flotaÃÃo-coagulaÃÃo

Raimundo Nonato Pereira Teixeira 12 February 2015 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Bodies of water contamination problems have stimulated many researchers around the world in the search for alternatives to solve or minimize the effects caused by discharges of toxic materials to the environment. What is desired, preferably, is that such solutions are economically viable and efficient. Toxic metals on the list of the main contaminants of water bodies. Because these are very dangerous chemicals, this class of materials has led many research groups seeking to achieve avoid contamination of water bodies by this type of material. The wastewater generated by electroplating industries have a high concentration of metal ions, so it should be treated before discharge to receiving waters. The processes using adsorption emerge as one of the research lines most valued by many researchers in order to contribute to this issue. Electrochemical processes have also been tested in the remediation of wastewater contaminated with various pollutants, including toxic metals. Natural clays play an important role in this type of study. Several studies have shown very promising results with the use of such material in the removal of toxic metals. This paper aims to conduct a comparative study of removal efficiency of Cu (II), Ni (II), Cd (II) and Pb (II) from six natural clays Brazilian soil. The clays were used: sodium Clay (AS), green clay (AV), clay chocolate calcium (ACCA), ferric clay (AF), attapulgite (AT) and kaolin (CAU). Balance studies were performed through adsorption isotherms in batch systems. For the balance of studies used monoelementares systems and multielement containing the four metal ions. We have also performed the kinetic study to evaluate the lower equilibrium times. Finally experiments were conducted with hybrid systems which use electrocoagulation-adsorption and coagulation with the purpose of working in a continuous system. The results show that all clays have good adsorption capacity for the four ions. The adsorption equilibrium results were compared with the Langmuir, Freundlich and Temkin. The maximum adsorption capacity obtained from monoelementares solutions were: 50.76 mg.g-1 [AS / Pb (II)], 50.76 mg.g-1 [AV / Cu (II)], 57.14 mg.g-1 [ACCA / Cu (II)], 34.72 mg.g-1 [AF / Cu (II)], 169.4 mg.g-1 [AT / Pb (II)] and 10 29 mg.g-1 [CAU / Cu (II)]. The kinetic model best suited to the experimental data was the pseudo second order. The Webber-Morri diffusion models and Boyd show that adsorption processes occur in more than one step and that in the early days predominates intrafilme diffusion process. The electrocoagulation-clotting experiments associated with adsorption with clays are promising because it promoted an increase in the removal capacity and facilitate the separation of the clay from the aqueous phase. The ion removal capacities of Cu (II) from industrial wastewater using the hybrid system were: 54% [AL / AS] to 45% [Al / ACCA] to 57% [Al / HF] 33% to [AL / AT], 48% / Problemas de contaminaÃÃo dos corpos hÃdricos tÃm estimulado muitos pesquisadores em todo mundo na busca de alternativas que resolvam ou minimizem os efeitos causados pelos descartes de materiais tÃxicos ao meio ambiente. O que se deseja, preferencialmente, à que tais soluÃÃes sejam economicamente viÃveis e eficientes. Os metais tÃxicos fazem parte da lista dos principais contaminantes dos corpos hÃdricos. Por se tratarem de substÃncias quÃmicas bastante perigosas, esta classe de material tem levado muitos grupos de pesquisa na busca de conseguir evitar a contaminaÃÃo dos corpos hÃdricos por este tipo de material. Os efluentes gerados pelas indÃstrias de galvanoplastia possuem uma elevada concentraÃÃo de Ãons metÃlicos, por isso devem ser tratados antes do descarte aos corpos receptores. Os processos que usam adsorÃÃo despontam como uma das linhas de pesquisas mais avaliadas por inÃmeros pesquisadores no intuito de contribuir com esta problemÃtica. Os processos eletroquÃmicos tambÃm tÃm sido testados na remediaÃÃo de efluentes contaminado por diversos poluentes, inclusive metais tÃxicos. As argilas naturais desempenham um papel importante neste tipo de estudo. Diversos trabalhos vÃm apresentando resultados bastante promissores com o uso deste tipo de material na remoÃÃo de metais tÃxicos. Este trabalho se propÃe a realizar um estudo comparativo de eficiÃncia de remoÃÃo dos Ãons Cu(II), Ni(II), Cd(II) e Pb(II) a partir de seis argilas naturais de solo brasileiro. As argilas utilizadas foram: Argila sÃdica (AS), argila verde (AV), argila chocolate cÃlcica (ACCA), argila fÃrrica (AF), atapulgita (AT) e caulim (CAU). Foram realizados estudos de equilÃbrio atravÃs de isotermas de adsorÃÃo em sistemas de batelada. Para os estudos de equilÃbrio utilizaram-se sistemas monoelementares e multielementares contendo os quatro Ãons metÃlicos. Realizou-se tambÃm o estudo cinÃtico para avaliarmos os menores tempos de equilÃbrio. Por fim foram realizados experimentos com sistemas hÃbridos que utilizam adsorÃÃo e eletroflotaÃÃo-coagulaÃÃo, com a finalidade de trabalharmos em sistemas contÃnuos. Os resultados obtidos mostram que todas as argilas apresentam boa capacidade de adsorÃÃo para os quatro Ãons. Os resultados de equilÃbrio de adsorÃÃo foram confrontados com os modelos de Langmuir, Freundlich e Temkin. As capacidades mÃximas de adsorÃÃo obtidas a partir de soluÃÃes monoelementares foram: 50,76 mg.g-1 [AS/Pb(II)], 50,76 mg.g-1 [AV/Cu(II)], 57,14 mg.g-1 [ACCA/ Cu(II)], 34,72 mg.g-1 [AF/ Cu(II)], 169,4 mg.g-1 [AT/Pb(II)] e 10,29 mg.g-1 [CAU/Cu(II)]. O modelo cinÃtico que melhor se adequou aos dados experimentais foi o de pseudo segunda ordem. Os modelos de difusÃo de Webber-Morri e Boyd demonstram que os processos de adsorÃÃo ocorrem em mais de uma etapa e que nos primeiros tempos predomina o processo de difusÃo intrafilme. Os experimentos de eletroflotaÃÃo-coagulaÃÃo associados à adsorÃÃo com argilas mostraram-se promissores porque promoveram um incremento nas capacidades de remoÃÃo e facilitam a separaÃÃo dos argilominerais da fase aquosa. As capacidades de remoÃÃo do Ãon Cu(II) a partir do efluente industrial usando o sistema hÃbrido foram: 54% para [AL/AS], 45% para [AL/ACCA], 57% para [AL/AF] 33% para [AL/AT], 48% para [FE/AS], 47% para [FE/ACCA], 54% para [FE/AF] e 40% para [FE/AT].
7

Influence du cobalt sur le comportement de l'hydroxyde de nickel dans les batteries alcalines du substituant au collecteur de charges

Gautier, Laurent 04 January 1995 (has links) (PDF)
Ce travail est consacre à la synthèse et à la caractérisation de nouveaux hydroxydes de nickel substitues au cobalt et à l'aluminium. La présence de 25% d'ions trivalents permet d'assurer la cohésion de la structure de type alpha, ainsi que la stabilité chimique de ces matériaux en milieu alcalin concentre. L'étude électrochimique montre que le couple alpha/gamma est parfaitement stabilise lorsque le taux d'aluminium est supérieur a 15%. En revanche, pour des taux inférieurs, il se produit une évolution progressive du couple alpha/gamma vers le couple bêta (II)/bêta (III), accompagnée d'une baisse de la capacité. Ce phénomène est du à une ségrégation des ions cobalt qui mené a une démixtion de la phase alpha initiale en un mélange d'hydroxyde de nickel et d'oxymydroxyde de cobalt de type bêta. Le système des oxyhydroxydes de cobalt a été étudié. Deux phases notées bêta (III) et gamma ont été préparées par chimie douce. Leurs structures ainsi que leurs propriétés électriques ont été clairement mises en évidence. Enfin, leur utilisation comme conducteur électronique post-rapporte a l'hydroxyde de nickel a conduit a des performances électrochimiques prometteuses sur le plan applique.

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