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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.
101

Development of 66 kV and 275 kV Class REBCO HTS Power Cables

Hayakawa, N., Ishiyama, A., Amemiya, N., Hasegawa, T., Saitoh, T., Yagi, M., Mukoyama, S., Ashibe, Y., Masuda, T., Okuma, T., Maruyama, O. 06 1900 (has links)
No description available.
102

Magnetic phase transitions in praseodymium-barium doped manganites

Chen, Michael H. January 2007 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
103

The Ba-Pb-O system and its potential as a solid oxide fuel cell (SOFC) cathode material /

Sharp, Matthew David. January 2007 (has links)
Thesis (M.Phil.) - University of St Andrews, September 2007.
104

[Beta]-barium borate thin film formation on silicon through metal organic decomposition of two novel precursors, barium dimesitylborinate and barium (18-crown-6) cyclotriboroxane /

Gross, Timothy M. January 2004 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 2004. / Typescript. Includes bibliographical references (leaves 121-123).
105

Temperature dependence of ceramic pyroeletric bolometer

Federer, James Clemens, January 1965 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 48.
106

Detaillierte Modellierung der Pt-katalysierten Schadstoffminderung in Abgasen moderner Verbrennungsmotoren

Koop, Jan January 2008 (has links)
Zugl.: Karlsruhe, Univ., Diss., 2008 / Hergestellt on demand
107

A study of the accuracy of the determination of sulfate as barium sulfate before and after the removal of metals precipitated by hydrogen sulfide ...

Millett, William Henry, January 1944 (has links)
Thesis (Ph. D.)--University of Pennsylvania, 1942. / Reproduced from type-written copy. Bibliography: p. 44.
108

Barium-tin alloys

Whanger, James Richard, January 1949 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1949. / Vita. The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 8, 2010) Includes bibliographical references (p. 65).
109

Filmes supercondutores do sistema YBsubaCsubuO

COELHO, ALVARO L. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:36:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:10Z (GMT). No. of bitstreams: 1 01819.pdf: 965861 bytes, checksum: 0c698783e4fc27b453a2c0225bd8ff99 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Fisica, Universidade de Sao Paulo - IF/USP
110

Síntese e caracterização ferroelétrica de compósitos cerâmicos planares de BaTiO3/BaTi1-xZrxO3 / Synthesis and ferroelectric characterization of planar BaTiO3/BaTi1-xZrxO3 ceramic composites

Thiago Martins Amaral 12 June 2015 (has links)
Compósitos cerâmicos planares de titanato zirconato de bário, BaTi1-xZrxO3, foram produzidos e os efeitos da quantidade de Zr4+ em suas propriedades funcionais foram estudados. As amostras foram fabricadas pelo método convencional de processamento cerâmico e pela técnica de deposição de fitas cerâmicas a partir de BaTi1-xZrxO3 com x=0, 0,05, 0,1, 0,15 e 0,2 sintetizados pelo método hidrotermal e pelo método dos precursores poliméricos. Foram realizadas caracterizações estrutural (difração de Raios X pelo método do pó e espectroscopia Raman), composicional (espectroscopia por dispersão de energia), microestrutural (microscopia eletrônica de varredura, ensaios de dilatometria) e funcional (permissividade elétrica, coeficiente piezoelétrico d33, coeficiente piroelétrico e histerese ferroelétrica). Além disso, a regra da mistura de fase foi utilizada para prever a permissividade elétrica dos compósitos e as tensões mecânicas internas e seus efeitos na permissividade elétrica e na temperatura de Curie de policristais de BaTiO3 foram simulados. As análises dos dados e as discussões foram realizadas considerando o modelo fenomenológico de Devonshire, a modificação de Forsbergh deste modelo para incluir efeitos de tensões mecânicas bidimensionais e o modelo de policristal tetragonal de BaTiO3 sugerido por Buessem. Os resultados mostram a existência de tensões residuais bidimensionais que surgem após o resfriamento dos compósitos devido às diferenças nos coeficientes de expansão térmica das fases constituintes. Os métodos de obtenção das amostras afetaram o tamanho final dos grãos e as espessuras das interfaces dos compósitos, sendo que, em geral, eles são menores e mais finos nas fitas cerâmicas homogêneas do que nas correspondentes cerâmicas homogêneas. Os compósitos apresentaram deslocamento da Tc para maiores temperaturas e aumento do grau de difusividade da transição. A presença das tensões mecânicas residuais e as características microestruturais, juntamente com os modelos utilizados, explicam qualitativamente a permissividade elétrica obtida. Concluí-se que a quantidade de Zr4+ modifica o comportamento das camadas durante a sinterização e altera o coeficiente de dilatação. Estas mudanças geram tensões mecânicas residuais que afetam a microestrutura e as propriedades funcionais dos compósitos. Portanto, a produção de compósitos cerâmicos ferroelétricos deve considerar a correlação existente entre microestrutura e tensões residuais para que suas propriedades sejam otimizadas. / Planar BaTi1-xZrxO3 ceramic composites had their functional properties investigated. These composites were obtained by the conventional ceramic processing technique and by tape casting technique. Furthermore, BaTi1-xZrxO3 x=0, 0.05, 0.1, 0.15 and 0.2 were synthesized by the polymeric precursors method and by the hydrothermal synthesis to study the synthesis influences and to study the effect of Zr4+ on the functional properties of the composites. Structural characterization (X-Ray powder diffraction and Raman spectroscopy), compositional analysis (energy dispersive X-Ray spectroscopy), microestrutural evaluation (scanning electron microscopy, dilatometry measurements) and functional properties characterization (electrical permittivity, piezoelectric coefficient d33, pyroelectric coefficient and ferroelectric hysteresis) were performed. Furthermore, the composites electrical permittivity was predicted by the simple mixture and the internal mechanical stress distribution and it´s effects on both, electrical permittivity and Curie´s temperature (Tc) of BaTiO3 polycrystals, were simulated. The analyses and discussions were supported by 1- Devonshire´s phenomenological theory, 2- Forsbergh´s modification to Devonshire´s theory to include the two-dimensional stress effects on Tc and 3- Buessem´s BaTiO3 tetragonal polycrystal model. The results show that the sintered composites present two-dimensional residual stresses after cooling due to the constrained sintering of the layers and their thermal expansion coefficient mismatch. The methods of sample preparation led to differences in grain size and interface thickness, with the homogeneous ceramic tapes presenting smaller grain sizes and thinner thickness than the conventional homogeneous ceramics. On the other hand, the composites showed a Tc shift to higher temperatures, a more diffuse phase transition and residual mechanical stresses. Concluding, the Zr4+ substitution of Ti4+ modifies the layer´s sintering behavior and their thermal expansion coefficient. These changes lead to microstructure modifications that affect the functional properties of planar BaTi1-xZrxO3 composites. Thus, the design of ferroelectric composites should take into consideration the correlations between microstructure and residual stresses in order to optimize their functional properties.

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