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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.
351

Effect of Z-Fiber® pinning on the mechanical properties of carbon fibre/epoxy composites

Troulis, Emmanouil January 2003 (has links)
This study investigates the effects of Z-pinning on the delamination performance in opening and shear loading modes in woven fabric reinforced / epoxy composite materials, as well as the effects of friction between specimen crack faces and the Z-pin failure mechanisms involved in mode II delamination. Mode I and mode II delamination tests are carried out on Z-pinned unidirectional (UD) and woven laminates. Both UD and woven laminates exhibit enhanced delamination resistance and crack propagation stability through Z-pinning. The effects of various structural and Z-pin parameters on the mode I and mode II delamination behaviour are separately assessed. The 4ENF testing configuration is deemed as the appropriate mode II configuration for the testing of Z-pinned laminates. A new basic friction rig is used to measure the friction coefficient between crack faces in woven laminates. An additional friction effect attributed to fibre architecture is identified. A specially designed delamination specimen is used to overcome the difficulty of accurately measuring crack propagation in Z-pinned woven fabric materials and aid data reduction using the available analytical methods. The failure mechanisms involved in the mode II delamination of Z-pinned laminates have been investigated with the implementation of a new test. Z-pins fail under shear loading through a combination of resin crushing, laminate fibre breakage, pin shear, pin bending and pin pullout. The balance of the failure mechanisms is shown to be a function of the crack opening constraint, material type, stacking sequence, Z-pin angle and insertion depth to Z-pin diameter ratio. Z-pin and material parameters influencing Z-pinning quality are identified, categorised and quantified. The importance of controlling Z-pin insertion depth is underlined and updated manufacturing procedures are proposed. Partial pinning appears as an advantageous alternative. A reduction in in-plane stiffness and in-plane strength in UD and woven fabric composites is measured, whilst no significant change of in-plane shear stiffness of UD materials is observed. A reduction in the fibre volume fraction is the single most important parameter affecting the in-plane stiffness. The performance of a Z-pinned sub-structural component is investigated. Enhanced loading carrying capacity and damage tolerance is achieved through Z-pinning.
352

A mistura dos bósons Z − Z′ e a quebra explícita da simetria leptônica no modelo 331 com neutrinos de m ao direita

Diniz Filho, Hermes Mangueira 02 October 2009 (has links)
Made available in DSpace on 2015-05-14T12:14:04Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 639748 bytes, checksum: 09ac6e93733c265a01578d25967f780c (MD5) Previous issue date: 2009-10-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this thesis, we develop some phenomenological aspects of a model based on the gauge symmetry SU(3)CNSU(3)LNU(1)N (311νR), that include righthanded neurinos in its matter content. We establish all the necessary structure for the study of the phenomenological aspects of the model. First, we obtain bounds on the angle that mix the gauge bosons Z and Z′, taking into account a requirement of the model, namely, that the number of fermionic families is exactly three. Also we implement the mass for both species of neutrinos (left-hand and right-handed) via type II seesaw mechanism, obtained adding to the model a sextet of scalars which will be responsible by the violation of the lepton number. The main consequence is the rising of a sterile neutrino with mass in the KeV range, satisfying all the cosmological and astrophysical constraints. This neutrino will a viable candidate for warm dark matter in the universe. / Nesta tese, desenvolvemos alguns aspectos relacionados `a fenomenologia de um modelo com simetria de gauge SU(3)CNSU(3)LNU(1)N (331νR), que possui neutrinos de m ao direita no seu conte´udo de mat´eria. Estabelecemos toda a estrutura necess´aria para o estudo dos aspectos fenomenol´ogicos do modelo. Primeiro, vamos obter v´ınculos no angulo que mistura os b´osons de gauge Z e Z′, levando em conta uma exig encia imposta pelo modelo, ou seja, que o n´umero de fam´ılias fermi onicas ´e exatamente tr es. Tamb´em implementamos termos de massa para ambas as esp´ecies de neutrinos (m ao esquerda e m ao dieita) via mecanismo seesaw tipo II, obtido adicionado ao modelo um sexteto de escalares, que ser´a respons ´avel pela viola¸c ao do n´umero lept onico. A principal consequ encia ´e o surgimento de um neutrino est´eril com massa na escala de KeV , satisfazendo todas as restri¸c oes cosmol´ogicas e astrof´ısicas. Esse neutrino ser´a um vi´avel candidato `a mat´eria escura morna do universo.
353

Biologický monitoring - jeho možnosti a omezení / Human biomonitoring - opportunities and limitations

Weissová, Iveta January 2010 (has links)
Human biomonitoring is a term for colleting and evaluating data concerning the pollution of environment and its influence on human body. In the CR it is being conducted since 1994 and its main aim is to protect people's health. The most commonly observed pollutants are heavy metals, PCBs, dioxins, chlorinated pesticides and many others. These pollutants find their way to the environment mainly due to people's industrial and agricultural activities. Smoking is still a current issue that needs to be addressed and it is an activity (voluntarily or in case of passive smoking involuntarily practiced) that causes health damage. Due to human biomonitoring, or more precisely due to principles which are now its foundation, many shortcomings of former industrial activities were discovered. Among others, it leads to understanding "Itai-itai" disease and discovering the cause of events in Japanese bay "Minamata". Today, the industrial (but also other) activities worldwide are at a high level of development. Many chemicals are being used and the environment is still being threatened. Based on those facts it is necessary to continually monitor the presence of toxic (or potentially toxic) substances in the environment and to put forth an extra effort to prevent exposure to these substances. Human biomonitoring is also...
354

Subdeprivace a její následky pro školní vývoj dítěte / Subdeprivation and its consequences for a school development of the child

KOLÁŘOVÁ, Kateřina January 2009 (has links)
My final work recognizes the syndrom known as psychological deprivation and subdeprivation. The theoretical part is aimed at defining the concept of psychological deprivation and subdeprivation and then focused on professor´s Matějček research, on whose methods and results is based the whole work. The empirical part of the research deals with a specific degree of psychological deprivation and subdeprivation in the constitutional institutions and families, and its detailed analysis.
355

Srovnání daně z příjmů u zaměstnanců a osob samostatně výdělečně činných v ČR a v Itálii / The comparison revenue taxes for employees wages and self earnest persons in Czech Republic and in Italy

KINDLMANNOVÁ, Iveta January 2010 (has links)
In this diploma project I am describing principles, purpose and construction of revenue taxes for nature persons in Czech Republic and in Italy and I am analyzing different between revenue taxes by Czech an Italy legal regulations. Czech revenue taxes for nature persons results from Zákon č. 586/1992 Sb., o daních z příjmů and the Italy revenue taxes for nature persons results from Testo unico del 22/12/1986 n. 917. In theory part there were analyzed parts of Czech and Italy revenue tax laws and taxation revenue from employment and from entrepreneurial activity more detailed. In practical part were chosen 5 examples on taxation of wages and 5 examples on taxation of business revenues. In these examples are demonstrated the biggest different in revenue taxation in Czech Republic and in Italy.
356

Investigação de efeitos ópticos não lineares de terceira e quinta ordens em colóides metálicos

OCAS, Albert Stevens Reyna 31 January 2012 (has links)
Submitted by Danielle Karla Martins Silva (danielle.martins@ufpe.br) on 2015-03-06T13:05:51Z No. of bitstreams: 2 Dissertacao final completa.pdf: 3283799 bytes, checksum: fb708d3c8c59f9ea4b40677bd2fe7ac7 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-06T13:05:51Z (GMT). No. of bitstreams: 2 Dissertacao final completa.pdf: 3283799 bytes, checksum: fb708d3c8c59f9ea4b40677bd2fe7ac7 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012 / CAPES ; CNPq / Coloides contendo nanopartículas metálicas são de amplo interesse para aplicações em áreas como fotônica ou plasmônica por apresentarem grande susceptibilidade óptica e resposta temporal ultrarrápida. Estes materiais são atraentes para aplicações de chaveamento e computação óptica, além de poderem ser usados para funções biomédicas como “genomics research” e “targeting” onde se exploram propriedades associadas aos plasmons superficiais das nanopartículas. Nesta Dissertação são analisados dois efeitos ópticos relacionados diretamente à existência do índice de refração não linear em coloides com nanopartículas de prata. Para isto foi utilizado o segundo harmônico de um laser de Nd:YAG cujo comprimento de onda é 532 nm. No primeiro estudo, utilizamos o efeito de Autofocalização para obter as susceptibilidades efetivas de terceira, c(3) e f f , e de quinta ordem, c(5) e f f , de coloides contendo nanopartículas de prata em acetona usando a técnica de Varredura-Z. Variando a concentração das nanopartículas na solução, podemos observar que, devido aos sinais opostos dos índices de refração não lineares das nanopartículas e do solvente, existe certa concentração na qual o índice de refração de terceira ordem do coloide, n2 µ Rec(3) e f f , se anula existindo ainda uma contribuição por parte do índice de refração de quinta ordem, n4 µ Rec(5) e f f . No outro estudo, foi explorado o efeito de Automodulação de fase espacial no coloide, mediante a análise da formação e evolução de padrões de difração de um feixe gaussiano que atravessa a amostra. Foi possível observar que a variação de fase induzida pelo índice de refração não linear, não tem um comportamento linear com a intensidade, verificando assim, as contribuições de termos de altas ordens.
357

Conversores Fonte Z para Sistemas Fotovoltaicos e Monofásicos-Trifásicos

BRADASCHIA, Fabrício 23 February 2012 (has links)
Submitted by Eduarda Figueiredo (eduarda.ffigueiredo@ufpe.br) on 2015-03-06T15:01:40Z No. of bitstreams: 2 Fabricio_Bradaschia_Tese_PPGEE_2012.pdf: 5723704 bytes, checksum: 25b5400bd74ff3ce76bd6b2571e20133 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-06T15:01:40Z (GMT). No. of bitstreams: 2 Fabricio_Bradaschia_Tese_PPGEE_2012.pdf: 5723704 bytes, checksum: 25b5400bd74ff3ce76bd6b2571e20133 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012-02-23 / Os avanços tecnológicos das chaves controláveis de potência abriram caminho para uma nova era da eletrônica de potência, possibilitando a produção industrial em larga escala de soluções usadas nas mais diversas áreas da tecnologia. Uma das últimas descobertas na área de topologias de conversores CC-CA trifásicos foi o inversor fonte Z, que foi apresentado como uma possível solução às barreiras conceituais e limitações técnicas apresentadas pelos inversores trifásicos fonte de tensão. Entretanto, há uma carência no meio científico de soluções que aplicam inversores fonte Z com ênfase na redução de custos, volume, peso e perdas no processo de conversão nas mais diversas áreas. Este trabalho, então, propõe contribuir em novas topologias e técnicas de modulação por largura de pulso para conversores fonte Z em sistemas fotovoltaicos trifásicos aterrados e sem transformador, e em sistemas de conversão monofásica-trifásica de baixo custo. Análises teóricas detalhadas e resultados de simulação e experimentais corroboram o funcionamento dos sistemas propostos e a eficácia dos mesmos em reduzir custo, volume, peso e perdas no processo de conversão.
358

Síntese/Fabricação e caracterização de micro e nanoestruturas para aplicação na fotônica e plasmônica.

SAADE, Jamil 31 January 2013 (has links)
Submitted by Etelvina Domingos (etelvina.domingos@ufpe.br) on 2015-03-11T19:49:39Z No. of bitstreams: 2 Tese Jamil Saade.pdf: 6694414 bytes, checksum: 3b234caf8498a768c97d1127fd50758d (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T19:49:39Z (GMT). No. of bitstreams: 2 Tese Jamil Saade.pdf: 6694414 bytes, checksum: 3b234caf8498a768c97d1127fd50758d (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / CNPq INCT PPGMT / O objetivo principal deste trabalho foi preparar e caracterizar coloides contendo estruturas micro e nanométricas de metais nobres (Ag e Au) para aplicações fotônicas. Tais estruturas apresentam propriedades ópticas, eletrônicas e catalíticas muito importantes que vêm sendo estudadas e exploradas exaustivamente desde a década passada. A produção destes colóides foi feita por três abordagens diferentes: Ablação laser em ambiente líquido (LAL), redução química na presença de agente oxidante e fotorredução utilizando LEDs de baixo custo operando na região do visível-infravermelho. Nas nanopartículas fabricadas por LAL em diferentes solventes na presença de PVP, o tamanho médio encontrado foi de 26,2 nm em água, 21,6 nm em álcool etílico e 18,7 nm em etileno glicol. As sínteses que empregaram reações de redução química e a fotoredução utilizando LEDs permitiram a sintonização das bandas de plasmons das nanopartículas variando a quantidade do precursor adicionado ao sistema e pela escolha do comprimento de onda de irradiação. A sintonizabilidade das bandas de plasmons das partículas sintetizadas por redução química foi possível na faixa de 460 a 850 nm. O tamanho médio das partículas produzidas por fotoredução foi encontrado na faixa de 30 a 150 nm dependendo do comprimento de onda do LED empregado. As frequências de ressonância dos plasmons de superfície destas partículas corresponderam aos comprimentos de onda de 475, 510, 580 e 725 nm obtidos por irradiação em 467, 475, 520 e 630 nm, respectivamente. Partículas micrométricas do tipo estrela e nanoprismas de ouro com tamanhos na faixa de 30 a 250 nm também foram preparados em etileno glicol e PVP por fotorredução com LEDs. A técnica de purificação dos colóides por centrifugação em gradiente viscoso de sacarose mostrou-se eficiente na homogeneização da dispersão de tamanhos e formas. O coeficiente de absorção de três fótons dos nanoprismas de ouro no comprimento de onda de 800 nm foi de ≈ 8,9 x 10-21 cm3/W2. As técnicas de caracterização empregadas neste trabalho foram: Absorção UV-visível, mobilidade eletroforética, Raios X, Microscopia Eletrônica de Transmissão (MET), Microscopia Eletrônica de Varredura (MEV), Difração de elétrons e Varredura - Z (Z-Scan).
359

Zdanění developerské společnosti / Development company taxation

Kašpar, Jan January 2017 (has links)
The aim of diploma thesis is to guarantee all requirements, which are necessary for providing a correct service of tax advisory. The main aim is devided into three parcial aims: description of development proces, analysis of related tax issues and to provide a development trends estimation. Methods used in this paper are recherche of related sources, interview with overal 13 consultants, analysis and folowing synthesis of reached knowledge. In comparison with another papers on similar topic, this text puts accent on practical aspects of development company taxation. Because of more precise understanding of commented issues, thesis provides chronological structure instead of classic thematical structure, used in most of similar papers. Thesis accomplished all the established objectives so it is efficient educational instrument mainly for a bookkeeperes and tax advisors, who needs to gain a knowledge of development as such, and it´s taxation.
360

Kriminologické aspekty trestných činů z nenávisti / Criminological Aspects of Hate Crime

Bouda, Jan January 2016 (has links)
The aim of this thesis on the topic of the Criminological Aspects of Hate Crime is to offer comprehensive point of view on this issues to the reader. The thesis is divided into five separate chapters. The first chapter is focused on definition of hate crime, specific characteristics of this criminality which distinguish it from other types of crime and also on typology of hate crime. The second chapter is concentrated to the Czech substantive legal regulation of hate crime and its possible regulatory options for the future in a first place. In its other part is focused on legal regulation of hate crime in the United States of America, Great Britain and Germany. In the last part of the chapter, the regulations of all these states are compared in terms of method which they used for anchoring hate crime in the legal system and how large their protection of minority is. The third chapter includes the issue of extremism which is defined at first and than divided into individual forms of extremism, based on their ideological bases and pursued aims, Furthermore, the attention is concentrated on the current state of the extremist scene in the Czech Republic, its activities and subjects. The final part of the chapter is devoted to concepts, closely related to extremism, like racism, anti-Semitism,...

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