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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.
171

Comportamento elétrico não convencional no KxMoO2-δ / Unconvetional Electrical Behavior in the KxMoO2-δ

Alves, Leandro Marcos Salgado 10 May 2010 (has links)
Molibdatos têm atraído grande atenção devido à existência de compostos com caráter elétrico unidimensional como conseqüência da presença de cadeias contendo ligações de Mo-O ou Mo-Mo em suas estruturas cristalinas. Com o objetivo de estudar molibdatos com esta característica, amostras policristalinas do sistema K-Mo-O foram preparadas pelo método de reação de difusão no estado sólido e caracterizadas por difratometria de raios x, propriedades elétricas e magnéticas. Estes resultados demonstram a existência de uma nova fase neste sistema com estequiometria KxMoO2-&#948;. Medidas da resistência elétrica em função da temperatura deste material mostram comportamento metálico anômalo que está relacionado a um ordenamento antiferromagnético. Foi observado ainda que a anomalia na resistência elétrica em baixas temperaturas (T < TM) comporta-se segundo uma lei de potência com expoente próximo de 0,5, o que sugere que o comportamento elétrico do KxMoO2-&#948; pode ser descrito por um mecanismo de condutividade unidimensional. / Molybdates have attracted great attention due to the existence of compounds which show one-dimensional electrical behavior as consequence of the channel containing Mo-O or Mo-Mo bonds in their crystalline structure. In order to study molybdates exhibiting onedimensional conductivity, polycrystalline samples of the K-Mo-O system were prepared using the solid state diffusion reaction method and characterized by X-ray powder diffractometry, electrical and magnetic properties. These results demonstrate the existence of a new phase in this system with KxMoO2-&#948; stoichiometry. Electrical resistance as a function of temperature measurements for this compound have shown anomalous metallic behavior which is related to an antiferromagnetic ordering. It has been also observed that the anomaly in the electrical resistance at low temperatures (T < TM) is fitted by power law temperature dependence with an exponent near 0.5 which suggests that the electrical behavior of the KxMoO2-&#948; can be well described by the one-dimensional conducting mechanism.
172

Attenuation of very fast transients in Sf6 insulated high voltage busducts. theoretical and experimental considerations of the effect of a ferromagnetic coating applied to busbars.

Jandrell, Ian Robert. January 1990 (has links)
A thesis submitted to the Faculty of Engineering at the University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. / Particularly at the higher system voltages, certain faults have been attributed to VFTs. This work presents a full frequency domain mathematical model of the effects likely to be introduced by the application of a thin ferromagnetic coating to the surfaces of the busbars as a means of attenuating these transients. Experimental verification shows the model to perform accurately as an analysis tool for a continuous coated co-axial system. While comparison between the model developed here (based on a planar conductor) and the very accurate Bessel function solution is presented, it must be remembered that it is not feasible to include the effects of coatings in the latter solution. Hence it is used merely as a bench-mark for improvements to the general model. Consideration is also given to the transient skin effect, and this is shown to result in an increased attenuation of VFTs. detectable during high voltage experimentation. The frequency domain model is extended to that of a full travelling wave model for VFTs in GIS. The Fourier technique is used to move between the frequency and time domains. Laboratory results obtained at high voltage.show that this technique will introduce both risetime increase and peak magnitude attenuation of VFTs. As the most frequent faults directly attributable to disconnector operation are known to be faults to earth at the switch, it is noted that the technique proposed in this work is uniquely suited for use in a design strategy that requires totally robust disconnectors at the expense of more severe VFTs in the GIS. The model is used to determine a range of physical characteristics of materials suitable for use in this application. While the characteristics of the most suitable materials have therefore been established, it is concluded that extensive metallurgical experimentation remains before this technique may be economically applied. / Andrew Chakane 2018
173

"Ett väldigt svårt, svårt uppdrag" : En undersökning gällande kompetenskrav för arbetsledare inom dagens äldreomsorg / "One very difficult, difficult commission" : A survey concerning compentens requirement for the work conductors within today´s geriatric care

Blom, Anna, Uhr, Camilla January 2008 (has links)
<p>Sammanfattning</p><p> </p><p>Arbetsledare är nyckelpersoner i äldreomsorgens verksamheter, de är en länk mellan högre chefer och de underställda medarbetarna. För att arbetet ska fungera på ett tillfredställande sätt, bör arbetsledaren ha den kompetens som krävs, för funktionen den har. Arbetsledarens funktion är att motivera och handleda medarbetarna för att omsorgstagarna i sin tur, ska få ett värdigt och gott liv. Undersökningens syfte var att undersöka gällande kompetenskrav för arbetsledare inom dagens äldreomsorg. Vi inriktade oss således på begreppen kompetens, utbildning och ledarskap. Studien grundas på fem samtalsintervjuer, genomförda med olika representanter inom området, på olika nivåer i samhället. Resultatet visade bland annat att det inte finns lagstadgade krav vad gäller en arbetsledares kunskapsnivå, men att den arbetsledande funktionen upplevs som mycket viktig och svår att hantera. Informanterna menar att det måste ställas vissa grundläggande krav på arbetsledarnas kompetens. Svaren visar även att arbetsledarna behöver en akademisk grundutbildning inom vård och omsorg, helst med inriktning mot äldre och handikappade. De anses även behöva en ledarskapsutbildning. Ett allmänt råd om kompetenskrav gällande arbetsledare är under diskussion hos Socialstyrelsen, samt om en legitimering är möjlig för denna yrkesgrupp.</p> / <p><p>Abstract</p><p> </p><p>The work conductors are the key persons in the geriatric care's activities and are a link between higher managers and the submitted employees. In order to get the work function in a satisfactory way, the work conductors should have the competence that is required. The work conductors’ function is to motivate and give guidance to the employees, so that the elderly people on that way can live a dignified and good life. The survey's aim was to examine applying competence requirement for work conductors within today's geriatric care. We concentrated on the concepts competence, education and leadership. The survey is based on five deliberation interviews, implemented with different representatives within the area, on different levels in the society. The result showed among other thing that there are not statutory requirements regarding work conductors knowledge level, but that the work conductive function is experienced as very important and difficult to handle. The interview persons mean that it must be set certain fundamental requirements, on the work conductors' competence. The replies are also showing that the work conductors need an academic basis education within care and long-term care, preferable with direction against the elderly and the disabled. They are considered to also need a leadership education. General advices of competence requirements are discussed at National Board of Health and Welfare and also perhaps try to legitimate this occupational group.</p><p> </p></p><p> </p><p> </p><p>The work conductors are the key persons in the geriatric care's activities and are a link between higher managers and the submitted employees. In order to get the work function in a satisfactory way, the work conductors should have the competence that is required. The work conductors’ function is to motivate and give guidance to the employees, so that the elderly people on that way can live a dignified and good life. The survey's aim was to examine applying competence requirement for work conductors within today's geriatric care. We concentrated on the concepts competence, education and leadership. The survey is based on five deliberation interviews, implemented with different representatives within the area, on different levels in the society. The result showed among other thing that there are not statutory requirements regarding work conductors knowledge level, but that the work conductive function is experienced as very important and difficult to handle. The interview persons mean that it must be set certain fundamental requirements, on the work conductors' competence. The replies are also showing that the work conductors need an academic basis education within care and long-term care, preferable with direction against the elderly and the disabled. They are considered to also need a leadership education. General advices of competence requirements are discussed at National Board of Health and Welfare and also perhaps try to legitimate this occupational group.</p>
174

Electromagnetic induction on an expanding conducting sphere.

January 1964 (has links)
References: p.71. / Contract DA36-039-AMC-03200(E). Grant DA-SIG-36-039-61-G14.
175

Perspectives on Choral and Solo Singing: Enhancing Communication Between Choral Conductors and Voice Teachers

Ferrell, Matthew August 15 December 2010 (has links)
Concepts of choral and solo singing diverge among the masses of pedagogues, teachers, and conductors who have differing opinions about healthy vocal technique and training. These differences have generated tension within some university music programs, with choral faculty and voice faculty sometimes on opposing sides. This document presents answers from professional singers who engage in choral and solo singing while maintaining a healthy vocal technique. All subjects interviewed for this document were asked to speak in detail to vocal adjustments made to sing in different styles. In addition, they were asked to identify any vocal faults that may arise from improper vocal production. The goal of this document is to lay grounds for valuable discussion regarding the opposing perspectives found in some academic circles with regard to proper vocal technique and training for choral and solo singing.
176

Implementation of the University of Missouri Terawatt Test Stand and the study of a large, multichanneling, laser tirggered gas switch

LeChien, Keith Robert, January 2006 (has links)
Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 27, 2007) Vita. Includes bibliographical references.
177

"Ett väldigt svårt, svårt uppdrag" : En undersökning gällande kompetenskrav för arbetsledare inom dagens äldreomsorg / "One very difficult, difficult commission" : A survey concerning compentens requirement for the work conductors within today´s geriatric care

Blom, Anna, Uhr, Camilla January 2008 (has links)
Sammanfattning   Arbetsledare är nyckelpersoner i äldreomsorgens verksamheter, de är en länk mellan högre chefer och de underställda medarbetarna. För att arbetet ska fungera på ett tillfredställande sätt, bör arbetsledaren ha den kompetens som krävs, för funktionen den har. Arbetsledarens funktion är att motivera och handleda medarbetarna för att omsorgstagarna i sin tur, ska få ett värdigt och gott liv. Undersökningens syfte var att undersöka gällande kompetenskrav för arbetsledare inom dagens äldreomsorg. Vi inriktade oss således på begreppen kompetens, utbildning och ledarskap. Studien grundas på fem samtalsintervjuer, genomförda med olika representanter inom området, på olika nivåer i samhället. Resultatet visade bland annat att det inte finns lagstadgade krav vad gäller en arbetsledares kunskapsnivå, men att den arbetsledande funktionen upplevs som mycket viktig och svår att hantera. Informanterna menar att det måste ställas vissa grundläggande krav på arbetsledarnas kompetens. Svaren visar även att arbetsledarna behöver en akademisk grundutbildning inom vård och omsorg, helst med inriktning mot äldre och handikappade. De anses även behöva en ledarskapsutbildning. Ett allmänt råd om kompetenskrav gällande arbetsledare är under diskussion hos Socialstyrelsen, samt om en legitimering är möjlig för denna yrkesgrupp. / Abstract   The work conductors are the key persons in the geriatric care's activities and are a link between higher managers and the submitted employees. In order to get the work function in a satisfactory way, the work conductors should have the competence that is required. The work conductors’ function is to motivate and give guidance to the employees, so that the elderly people on that way can live a dignified and good life. The survey's aim was to examine applying competence requirement for work conductors within today's geriatric care. We concentrated on the concepts competence, education and leadership. The survey is based on five deliberation interviews, implemented with different representatives within the area, on different levels in the society. The result showed among other thing that there are not statutory requirements regarding work conductors knowledge level, but that the work conductive function is experienced as very important and difficult to handle. The interview persons mean that it must be set certain fundamental requirements, on the work conductors' competence. The replies are also showing that the work conductors need an academic basis education within care and long-term care, preferable with direction against the elderly and the disabled. They are considered to also need a leadership education. General advices of competence requirements are discussed at National Board of Health and Welfare and also perhaps try to legitimate this occupational group.       The work conductors are the key persons in the geriatric care's activities and are a link between higher managers and the submitted employees. In order to get the work function in a satisfactory way, the work conductors should have the competence that is required. The work conductors’ function is to motivate and give guidance to the employees, so that the elderly people on that way can live a dignified and good life. The survey's aim was to examine applying competence requirement for work conductors within today's geriatric care. We concentrated on the concepts competence, education and leadership. The survey is based on five deliberation interviews, implemented with different representatives within the area, on different levels in the society. The result showed among other thing that there are not statutory requirements regarding work conductors knowledge level, but that the work conductive function is experienced as very important and difficult to handle. The interview persons mean that it must be set certain fundamental requirements, on the work conductors' competence. The replies are also showing that the work conductors need an academic basis education within care and long-term care, preferable with direction against the elderly and the disabled. They are considered to also need a leadership education. General advices of competence requirements are discussed at National Board of Health and Welfare and also perhaps try to legitimate this occupational group.
178

Nanocrystalline Metal Enabled Conductors for Enhanced Strength-to-weight Aerospace Electrical Wiring

Winfield, Ian 28 July 2010 (has links)
High strength-to-weight nanocrystalline alloy enabled conductor (NEC) prototypes were successfully developed by reinforcing an oxygen-free copper core material with electrodeposited cobalt phosphorus (CoP) coatings. A rule of mixtures approach was utilized to design the NEC prototypes to meet materials performance indices. Three unique NEC prototypes were produced with CoP coatings composed of alternating nanocrystalline (11 nm) and coarse-grained layers. The tensile properties were dependant on the coating microstructures, with tensile strengths of 1000 MPa, 970 MPa, and 900 MPa, respectively, and corresponding tensile elongations of 4.6%, 6.1%, and 10%, respectively. The electrical conductivity of the NEC prototypes was ~58 %IACS (resistivity of ~2.96 µΩ-cm). The rule of mixtures approach effectively predicted the tensile strength and conductivity. The NEC samples were significantly stronger than the incumbent high-strength aerospace conductor material, Be-Cu alloy CS95, which exhibits a tensile strength of only 655 MPa and conductivity of 63 %IACS.
179

Nanocrystalline Metal Enabled Conductors for Enhanced Strength-to-weight Aerospace Electrical Wiring

Winfield, Ian 28 July 2010 (has links)
High strength-to-weight nanocrystalline alloy enabled conductor (NEC) prototypes were successfully developed by reinforcing an oxygen-free copper core material with electrodeposited cobalt phosphorus (CoP) coatings. A rule of mixtures approach was utilized to design the NEC prototypes to meet materials performance indices. Three unique NEC prototypes were produced with CoP coatings composed of alternating nanocrystalline (11 nm) and coarse-grained layers. The tensile properties were dependant on the coating microstructures, with tensile strengths of 1000 MPa, 970 MPa, and 900 MPa, respectively, and corresponding tensile elongations of 4.6%, 6.1%, and 10%, respectively. The electrical conductivity of the NEC prototypes was ~58 %IACS (resistivity of ~2.96 µΩ-cm). The rule of mixtures approach effectively predicted the tensile strength and conductivity. The NEC samples were significantly stronger than the incumbent high-strength aerospace conductor material, Be-Cu alloy CS95, which exhibits a tensile strength of only 655 MPa and conductivity of 63 %IACS.
180

Work function fluctuation analysis of polyaniline films

West, Ryan Matthew 20 March 2013 (has links)
In this thesis, the development of a novel experimental technique for measuring the spontaneous, stochastic work function (WF) fluctuations of conducting polymer films, at equilibrium, is discussed. Polyaniline (PANI) is studied as a representative conducting polymer. This technique utilizes an insulated-gate field-effect transistor (IGFET) with PANI gate electrode (PANI-IGFET). The fluctuations of PANI WF are transduced into measurable drain current fluctuations of the device. By analyzing these fluctuations while systematically controlling the temperature, electric field and doping level, a model of WF fluctuations in PANI films is developed. These experiments suggest that the source of WF fluctuations is the hopping of charge carriers, or trapping/detrapping of charge carriers, around the Fermi level of the PANI film at the PANI-insulator interface. This process is thermally activated with a field and doping dependent activation energy in the range of 0.1 to 0.5 eV. Thus, this new technique provides detailed information about charge-carrier dynamics in the space-charge region of the PANI film, at equilibrium. These results have important implications for organic electronics and furthering fundamental understanding of the relationship between doping, disorder and work function in organic semiconductors.

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