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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.
111

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
112

Proposta e validação de uma nova metodologia para medição automatizada de folgas de trabalho em sistemas de direção automotiva

Aimi, Vinícius January 2010 (has links)
Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.
113

Estudo ultra-estrutural e citoquímico da relação entre o desenvolvimento da musculatura do vôo e a demanda por vôo dos componentes de colônias de abelhas eussociais /

Winckler, Fernanda Fernandez. January 2008 (has links)
Orientador: Carminda da Cruz-Landim / Banca: Ana Maria Costa Leonardo / Banca: Flávio Henrique Caetano / Banca: Zilá Luz Paulino Simões / Banca: José Eduardo Serrão / Resumo: Apini e Meliponini são tribos compostas por espécies de abelhas classificadas como eussociais avançadas e, portanto, apresentam divisão de trabalho reprodutivo entre as castas femininas e complexas adaptações comportamentais, adquiridas durante a evolução pelas operárias, para desempenhar as tarefas relativas à manutenção da colônia. A capacidade de voar dos adultos destes insetos está intrinsecamente ligada à maioria de suas atividades como o vôo nupcial para o acasalamento no caso das rainhas e machos e a exploração de novo habitat, fontes de alimentos e estabelecimento de novos ninhos no caso das operárias. Tanto em Apis mellifera, quanto em Scaptotrigona postica, o vôo é realizado por músculos denominados músculos indiretos do vôo por não apresentarem ligação direta com as asas. A contração desses músculos produz mudanças de volume no tórax e indiretamente, o movimento das asas. O objetivo deste projeto foi realizar medidas das fibras desse músculo em cada indivíduo e em cada fase da vida, aplicando aos resultados teste estatístico apropriado para verificar possíveis diferenças de desenvolvimento que possam ser relacionadas à função muscular e comparar a ultraestrutura e citoquímica da musculatura do vôo das castas femininas (rainhas e operárias) e machos em diferentes fases da vida, tendo em vista as diferenças comportamentais e fisiológicas entre as classes de indivíduos das duas espécies. O exame da musculatura do vôo, tanto com microscopia de luz como com microscopia eletrônica de varredura e transmissão, mostrou que o arranjo e a morfologia dos feixes musculares e das fibras que os compõe são similares nas duas espécies, no entanto os feixes musculares de Apis mellifera são formados por número maior de fibras. Medições das larguras das fibras mostraram diferenças estatisticamente significante entre as fases da vida... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Apini and Meliponini are tribes composed of species of advanced eusocial bees and therefore present division of reproductive labor between females and complex behavioral adaptations, acquired during the evolution by workers, to attend the responsibilities for the maintenance of the colony. The ability of adults to fly is intrinsically linked to most of their activities as the nuptial flight for mating in the case of queens and males and exploitation of new habitat, sources of food and establishment of new nests in the case of workers. Both in Apis mellifera, as in Scaptotrigona postica, the flight is accomplished by muscles called indirect flight muscles by not make a direct connection with the wings. The contraction of muscles produces changes in volume in the torax and indirectly, movement of the wings. The objective of this project was to perform measurements of muscle fibers from every individual in every stage of life, applying the appropriate statistical test to results in order determine possible differences in development that may be related to muscle function. Alsoo compare the ultra-structure of and cytochemistry of workers, queens and males flight muscle at different stages of life, with the behavioral and physiological differences between the classes of individuals of the two species. The examination of the muscles of the flight, both with light microscopy, and with scanning and transmission electron microscopy, showed that the arrangement and morphology of the muscle fibers bundles arrangement is similar in the two species, however the muscle bundles of Apis mellifera are formed by larger number of musclefibres. Measurements of the width of the fibers showed statistically significant differences between the life phases of the colonies components and between species. Similarly the ultra-structural examination showed that workers of both species emerge with... (Complete abstract click electronic access below) / Doutor
114

Motifs structuraux dans des verres modèles pour le stockage des actinides / Structural motifs in model aluminosilicate glasses for the storage of actinides

Hiet, Julien 16 November 2009 (has links)
Les matrices vitreuses aluminosilicatées de lanthanides {SiO2 –Al2O3 – (CaO) – Y2O3 – La2O3} constituent, une matrice potentielle d’intérêt nucléaire, dans le cadre du stockage des déchets des actinides. Alors que de nombreuses études sont encore menées pour établir leurs propriétés macroscopiques (durabilité, mécanismes de vitrification, etc…), nous nous sommes attachés à décrire l’environnement proche des noyaux qui composent le réseau, c'est-à-dire leur structure à une échelle locale. Les verres aluminosilicatés sont constitués de tétraèdres d’aluminium et de silicium. Plus précisément, ils sont constitués d’entités Qn(mAl) silicium et d’entités qn(mSi) aluminium. Cependant, il est rare d’aboutir à une description en ces termes. La Résonance Magnétique Nucléaire haute résolution solide (RMN MAS 27Al et 29Si) est un des moyens d’y parvenir. Nous proposons ici le développement de séquences d’impulsions permettant l’identification de ces unités puis la description de leurs connectivités via leurs liaisons chimiques, basées sur le filtrage des cohérences MultiQuanta associées aux couplages scalaires J2 (Si-O-Si) et J2 (Si-O-Al). Cette approche RMN permet donc d’affiner la compréhension des réseaux aluminosilicatés quels qu’ils soient. Couplé à la spectroscopie RAMAN, elle a pu ensuite nous servir comme référence pour établir la structure et le comportement à long terme de ces matrices, suite à des expériences de lixiviation statique et d’irradiation a pratiquées au cyclotron du CEMHTI. / Aluminosilicate glasses of rare earth {SiO2 –Al2O3 – (CaO) – Y2O3 – La2O3} can be considered like a potential matrix of nuclear waste. This type of glass appears to be suitable matrix for the specific immobilization of trivalent actinides. Whereas many studies dealt with the macroscopic properties of these matrix (durability, mechanism, etc…), we investigate here the local environment surrounding the nucleus constituting the vitreous network. Thus, we can say that we investigate the local structure of the glass. Aluminosilicate glasses are constituted with silicon and aluminium tetrahedra. They are more especially based on a mixture of silicon Qn(mAl) and aluminium qn(mSi) units. Up to now, few experiments allow to describe the vitreous network with this terminology. A solution is the High Resolution Solid State NMR : 27Al and 29Si 1D or 2D MAS NMR experiments. We proposed here to provide and improve NMR pulse sequence to evidence NMR signatures of chemically bounded Al-O-Si and Si-O-Si molecular motifs and to establish an approximate picture of medium range order, thanks to 27Al/29Si heteronuclear and 29Si/29Si homonuclear NMR experiments associated to MultiQuantum filtering based on indirect scalar coupling J2 Al-O-Si/J2 (Si-O-Si) and. Combining RAMAN spectroscopy, Spin counting and MultiQuantum filtering allow establishing an approximate and new picture of medium range order in aluminosilicate compounds. Thus, they offer a reference to describe the changes in the structure and the long term behavior of our aluminosilicate glasses of rare earth, induced by static lixiviation and a irradiation practiced to cyclotron in CEMHTI laboratory .
115

As atividades tecnologicas pos-privatização do setor de telecomunicações no Brasil / Technological activities in the telecommunicatios sector in Brazil after privatization

Camillo, Edilaine Venancio, 1981- 30 August 2005 (has links)
Orientador: Sergio Robles Reis de Queiroz / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-05T08:29:02Z (GMT). No. of bitstreams: 1 Camillo_EdilaineVenancio_M.pdf: 3778361 bytes, checksum: 55aa017934e31fa94cedc82be73a8ab6 (MD5) Previous issue date: 2005 / Resumo: O objetivo desse trabalho é analisar as atividades tecnológicas realizadas pelo setor de telecomunicações no Brasil após a privatização com base na literatura disponível. Para tanto, aborda-se, primeiramente, as trajetórias institucional e tecnológica do setor no âmbito internacional, destacando a expansão da cadeia produtiva e a mudança no regime de inovação da indústria de telecomunicações, tendo como conseqüência o redirecionamento do foco das atividades de pesquisa. A seguir, faz-se uma retrospectiva histórica acerca das telecomunicações no Brasil, dedicando maior ênfase às políticas de fomento à indústria nacional, e ao processo de desregulamentação e liberalização do setor, determinantes na composição e capacitação tecnológica atual da indústria de telequipamentos presente no país. Essas colocações prévias visam contextualizar e balizar a análise proposta, delineada em torno das duas esferas centrais no processo de capacitação tecnológica do setor em estudo: a) o Centro de Pesquisa e Desenvolvimento (CPqD); e b) e os fabricantes locais de equipamentos. Nesse sentido, são apresentadas e debatidas as evidências diretas e indiretas contidas nos trabalhos estudados. A partir disso, conclui-se que não há evidências concretas sobre a redução dos esforços tecnológicos do setor de telecomunicações no período pós-privatização / Abstract: The purpose of the work is to analyze, based on the existing literature, the technological efforts undertaken by the Brazilian telecommunications sector after its privatization (in the 1990¿s). Initially, it discusses the institutional and technologic trajectories at the international level, the changes in the telecom industry¿s innovation regime and, consequently, the change in its R&D activities. Second, is traced the historical background about Brazilian telecommunications industry, emphasizing the policies towards the sector, and also the determining factors of the current structure and technological competence of the local telecom equipments industry. These previous analyses provide the context to the proposed exam the proposed exam, focused on the two main actors of technological development in the referred sector: the ¿Centro de Pesquisa e Desenvolvimento em Telecomunicações¿ (CPqD) and the local telecom equipment producer. In this sense, the direct and indirect evidences highlighted in the preceding works are presented and discussed. The main conclusion is that there are no strong evidences about the reduction of technological efforts in the Telecom sector after privatization / Mestrado / Mestre em Política Científica e Tecnológica
116

An analysis of the prevalence of gender discrimination in indirect taxation in South Africa

Swanepoel, Sumarie 11 June 2014 (has links)
M.Com. (South African and International Taxation) / Tax policy is important on many levels. It directly affects all members of society. The gender impact of these polices is often overlooked. The study was motivated by the potential existence of unintended gender discrimination within various indirect taxes. Tax policy has real repercussions on household budgeting and spending. The impact is likely to differ between the genders and this should be taken into account when setting tax policy in order to maintain fairness. Value Added Tax and the national lottery are all regressive taxes and affect the poor more than the wealthy. In light of the feminisation of poverty, as well as different household responsibilities and spending patterns between men and women, the gendered effect of this regressive tax is significant. This study considers whether South Africa’s indirect tax legislation and policies result in gender discrimination and what the potential solutions are. A largely qualitative approach was undertaken in executing the research. This entailed detailed reading on the topic to support any inferences and conclusions. This study finds that indirect gender discrimination exists in South Africa’s indirect taxation system and policy. The discrimination arises mostly due to the regressive nature of indirect taxes. These taxes have far larger ramifications for the poor. Women make up most of the poorest people both in South Africa and around the world. Men and women also spend differently and their spending and decision making directly affects household disposable income. The result of these gendered spending patterns could be said to put woman at a disadvantage in certain cases. The introduction of additional zero-ratings on children’s clothing and personal hygiene products could go far in addressing discrimination without a huge impact to the fiscus.
117

Government export promotion programmes and firms' export behaviour : exploring the indirect link : the case of UK & Algerian manufacturing firms

Haddoud, Mohamed Yacine January 2015 (has links)
It has been recognised that exporting is an engine for growth at both country and firm levels. However, the challenging nature of international business often prevents companies from entering and surviving in international markets. In the Small and Medium-size Business context, lack of resource is normally the main reason behind the inability of firms to overcome export barriers. In recognition of the issue and for promoting exporting, the governments have been offering the so-called Government Export Promotion Programmes (GEPPs) to act as “resource supplements”. While there have been extensive practices, the mechanism and effectiveness of these programmes have not been thoroughly explored and analysed. In some academic studies, criticisms and doubts about these programmes have been raised. Against this background, the thesis investigates the working mechanism of these programmes and tests their effectiveness in terms of export initiation, performance and regularity. Using an extended version of the Resource Based View, two integrative and comprehensive conceptual models are developed in order to reveal the indirect impacts of GEPPs on export behaviour. The models are then tested with a total of 495 completed questionnaires collected from two sample countries; namely, Algeria and the UK. These were analysed through a multivariate analysis using a variance-based statistical technique known as Partial Least Squares Structural Equation Modelling. The findings of this thesis are two-fold. First, with respect to the critical resources affecting export behaviour, the study finds that while both Algerian and UK firms’export intention are affected by management resources only, firms’ export performance and regularity are instead mainly influenced by management and organisational resources in the UK and management and relational resources in Algeria. Second, regarding the impact of GEPPs on export intention, the study confirms its indirect nature through the management resources in both countries. However, when it comes to their effect on export performance and regularity, the indirect effect was only established in the UK and mainly through management and organisational resources. These findings have both theoretical and practical implications in that the results have provided empirical evidence on the indirect impact of GEPPs and can serve as an indication in practice for both firm managers and policy makers in deploying key resources for different stages of internationalisation.
118

Experimental determination of spin-spin coupling tensors applying NMR of partially oriented molecules

Kaski, J. (Jaakko) 02 June 1999 (has links)
Abstract The indirect spin-spin coupling is a molecular internuclear interaction, which is observable by utilizing NMR spectroscopy. This coupling, denoted J, is a second-order tensorial property that consists of rank-0, 1, and 2 components. The present thesis deals with the experimental determination of the rank-0 and rank-2 components of J tensors for different pairs of interacting nuclei by utilizing liquid crystal NMR (LC NMR) method. The experimental information of the rank-2 component of the J tensor appears as Janiso, a combination of tensor elements. In LC NMR, Janiso is manifested as a contribution to the experimental anisotropic coupling (Dexp ) that contains also the corresponding internuclear dipolar coupling, D. The dipolar coupling is defined by the molecular geometry and average orientation, and affected by the molecular motions. Therefore, the molecular geometry and orientation have to be determined together with the studied Janiso couplings. The contributions to D couplings arising from the molecular vibrations and solvent-induced deformation of the molecular geometry are taken into account in the analysis of the experimental data; the contributions are presented briefly in this thesis. The LC NMR experiments are performed for C6H6, HCONH2, C2H2, C2H4, C2H6, 1,4-C6H4F2, CH3F, CH2F2, CHF3, and CSiH6 molecules, and some important aspects of the liquid crystal NMR method are discussed. The obtained information of J tensors is compared with the theoretical ab initio MCSCF results. Finally, the systematics of the J tensors in different structural surroundings is found and the significance of the indirect contribution to the corresponding Dexp coupling is discussed.
119

Novel P2Y12 Receptor Antagonists - Prasugrel and Ticagrelor. Systematic Review, Indirect Comparison to Clopidogrel in Cardiovascular Disease, Design of a Randomized Controlled Trial

Steiner-Boeker, Sabine January 2011 (has links)
Antiplatelet therapy with clopidogrel is widely used in patients with coronary artery disease, but the recent development of the new P2Y12 receptor antagonists prasugrel and ticagrelor will increase treatment options. An overview of systematic reviews was performed to summarize available evidence on clopidogrel. Current data on prasugrel and ticagrelor were identified by a systematic review and used for an indirect treatment comparison (ITC) of the drugs against each other and versus placebo in the absence of head-to-head clinical trials. Adjusted indirect comparison according to Bucher, Bayesian methods for mixed treatment comparisons using Winbugs, and generalized linear mixed models using SAS were employed for ITC, yielding almost identical results: prasugrel was favored regarding stent thrombosis and ticagrelor regarding major bleeding. However, substantial differences in trial design were identified, demanding caution when interpreting these results. On the basis of the obtained results, a randomized controlled trial was designed within the gap of current evidence.
120

Perceptions of Female Aggression on Reality Television

Donovan, Kathleen January 2016 (has links)
Despite the detrimental effects of aggression, Reality Television is replete with portrayals of female direct and indirect aggression for the sake of entertainment. Direct, physical and verbal aggression may be easy to identify but indirect aggression can be circuitous and subtle such as gossiping and exclusion from the group. Victims of indirect aggression can experience long-term psychological repercussions such as depression, anxiety, low self-esteem and self-abusive behaviour. Exposure to indirect relational aggression on Reality Television has also been shown to increase physical aggression in its viewers. Combining three theoretical frameworks this study draws on social cognitive theory, cultivation theory as well as feminist frameworks. Female adults were recruited to participate in semi-structured interviews discussing their perceptions and influence of Reality Television clips portraying female aggression.

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