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Le moteur essence à allumage par compression (GCI), reposant sur la combustion partiellement prémélangée de l'essence (GPPC), peut potentiellement assurer des opérations efficaces et propres. Le moteur GCI s'est avéré efficace à forte charge, mais l'indice d'octane élevé de l'essence limite considérablement les opérations à faible charge. Le présent travail étudie le potentiel de l'utilisation de l'ozone, fort agent oxydant, pour améliorer la réactivité de l'essence et permettre le fonctionnement à faible charge de GCI. L'ozone peut être produit on board en équipant le moteur d'un générateur d'ozone, sans impact dramatique sur le coût du moteur et sur la complexité du contrôle du moteur. Les essais effectués avec un moteur monocylindre ont montré que l'ozone favorise la combustion HCCI de l'essence, permettant d'étendre la limite d’auto-inflammation et de réduire la température minimale nécessaire de celle-ci. Les diagnostics optiques ont montré que ces propriétés sont liées à une prolifération radicale accrue, amenées par des réactions à basse température induites par l'ozone. En parallèle, le processus de combustion GCI a été étudié dans des conditions de faible charge. Sans ozone, la température d'admission doit être considérablement augmentée pour permettre l'auto-inflammationdes mélanges essence-air pauvres. De plus, les résultats indiquent que le monoxyde d’azote (NO) contenu dans les gaz brûlés résiduels peut, dans certaines conditions, favoriser fortement la combustion GCI. Ensuite,l'effet de l'ozone a été étudié dans des conditions d'injection directe GCI. Les résultats démontrent qu’une stratégie avec double injection est nécessaire pour maximiser l’effet promoteur de l’ozone et pour contrôler le processus de combustion GCI. Enfin, l'utilisation d’une forte concentration d’ozone a permis d’atteindre des opérations à faible charge en mode GCI, avec des faibles émissions de NOx et de suie, et cela, sans avoir besoin d'augmenter la température ou la pression d'admission. / Gasoline Compression Ignition (GCI) engine, relying on Gasoline Partially Premixed Combustion (GPPC) has potential for efficient and clean operations. GCI engine showed to be effective at high load, however, the highoctane number of gasoline dramatically limits low load operations. The present work investigates the potential of using ozone, a strong oxidizing agent, to improve gasoline reactivity and enabling low load GCI operation.Ozone can be produced in-situ and on-demand by equipping the engine with an ozone generator, without a dramatic impact on the engine cost and the engine control complexity. Experiments in a single cylinder engine showed that ozone promotes gasoline HCCI combustion, making possible to extend the lean limit and reducing the minimum temperature needed for autoignition. Optical diagnostics showed that these properties are related to an increased radical proliferation related to ozone-induced low temperature reactions. In parallel, GCI combustion process was investigated under low load conditions. Without ozone, the intake temperature should be considerable increased to enable auto ignition of lean gasoline-air mixtures. Moreover, results indicated that the NO contained into residual burnt gases can strongly promote GCI low load combustion. Finally, the effect of ozone was investigated under GCI direct-injection conditions, demonstrating that low load GCI operation with low NOx and Soot emission can be achieved by seeding the intake of the engine with ozone without needing of increasing the intake charge temperature or boosting the intake pressure.

Esta tese aborda a relação entre a gestão de custos inter-organizacional (GCI), custos de transação (CT), e gestão de riscos em alianças (GRA) em empresas que operam no Brasil. O método de pesquisa foi o survey, com aplicação de um questionário. Os níveis de GCI, CT e GRA foram medidos tendo como base a percepção dos gestores de compras e suprimentos das empresas selecionadas. A amostra teve 85 respostas válidas, de 5 setores da indústria de manufatura (automotivo, bens de consumo, eletrônica, química e metalurgia). Os resultados demonstram uma associação significativa entre GCI e GRA, isto é, empresas que adotam a abordagem de gestão de custos inter-organizacional com maior intensidade possuem maior ênfase nas práticas de gestão de riscos. Além disso, verificou-se que a abordagem de GCI e GRA não afetam a percepção dos gestores sobre os CT, ou seja, a adoção de gestão de custos inter-organizacional não aumenta a percepção de custos de transação quando esta abordagem é adotada juntamente com práticas de gestão de riscos em alianças. Além disso, verificou-se que as empresas do setor de eletroeletrônicos apresentaram maiores níveis de GCI, enquanto as empresas da indústria automotiva tiveram os menores, demonstrando que empresas desse setor possuem menor propensão a compartir recursos, informações e tecnologia com seus fornecedores. Com relação à percepção de custos de transação e práticas de gestão de riscos, a análise demonstrou que não há diferenças significativas entre os setores estudados. Adicionalmente, os resultados demonstram que as empresas que utilizam ferramentas de gestão de custos, tais como custeio baseado em atividades (ABC) ou custeio alvo, possuem maiores níveis de GCI, o número de fornecedores e o tamanho desses parceiros também influencia na intensidade com que as empresas adotam a abordagem de GCI. Em relação à percepção de custos de transação, os resultados revelam que a experiência dos gestores e do tamanho da companhia influenciam na visão sobre os custos de transação. Já em relação às práticas de gestão de riscos em alianças, os resultados demonstram que as empresas que possuem acordos de ganhos compartilhados com fornecedores tendem a adotar mais intensamente as práticas GRA, além disso, o tamanho do fornecedor e setor de atuação da empresa também influenciam na intensidade com que tais práticas são adotadas. As principais contribuições deste trabalho foram o desenvolvimento de instrumentos para mensuração do nível de adoção de práticas de GCI e GRA, bem como a investigação empíricas sobre a relação entre percepção de GCI, CT e GRA. / This PhD dissertation addresses the relationship between inter-organizational cost management (IOCM), transaction costs (TC), and alliance risk management (ARM) in companies operating in Brazil. The research method consists in applying a survey questionnaire. The scores of IOCM, TC, and ARM were measured having the perception of purchase and supply managers of selected firms as a basis. The sample has 85 valid answers, from 5 sectors of the manufacturing industry (automotive, consumer goods, electronics, chemical, and metallurgy). The results demonstrate a significant association between IOCM and ARM, that is, companies adopting an inter-organizational cost management approach have more emphasis on practices of alliance risk management. Besides, it was found that IOCM and ARM approach do not affect the manager\'s perception about TC, thus, adoption of inter-organizational cost management approach does not increases perception of transaction cost since this approach is combined with practices of alliance risk management. Moreover, it was found that firms from the electronics industry have the highest level of IOCM, while automotive industry firms have the lowest, showing that automotive firms has less likelihoods to share resources, information and technology with suppliers. Regarding perception of transaction cost and alliance risk management, there is no significant difference between the industries studied. Additionally, the research demonstrates that companies using a cost management tool, such as activity-based costing (ABC) or target costing, have a higher level of IOCM, number of suppliers and the size of partners also influences the intensity as firms adopting IOCM approach. Regarding the perception of transaction costs, the results reveal that both manager\'s experience and company size influence the perception of transaction cost. Concerning the practices of alliance risk management, the results demonstrate that the firms having earnings-sharing agreements with suppliers apply more ARM practices, also, the size of suppliers and the industry of the firms influences the intensity as firms adopt practices of alliance risk management. The main contribution of this study was the development of an instrument to measure the level of IOCM and ARM, as well as an empirical investigation of the relationship between perceived level of IOCM, TC and ARM.

Esta tese aborda a relação entre a gestão de custos inter-organizacional (GCI), custos de transação (CT), e gestão de riscos em alianças (GRA) em empresas que operam no Brasil. O método de pesquisa foi o survey, com aplicação de um questionário. Os níveis de GCI, CT e GRA foram medidos tendo como base a percepção dos gestores de compras e suprimentos das empresas selecionadas. A amostra teve 85 respostas válidas, de 5 setores da indústria de manufatura (automotivo, bens de consumo, eletrônica, química e metalurgia). Os resultados demonstram uma associação significativa entre GCI e GRA, isto é, empresas que adotam a abordagem de gestão de custos inter-organizacional com maior intensidade possuem maior ênfase nas práticas de gestão de riscos. Além disso, verificou-se que a abordagem de GCI e GRA não afetam a percepção dos gestores sobre os CT, ou seja, a adoção de gestão de custos inter-organizacional não aumenta a percepção de custos de transação quando esta abordagem é adotada juntamente com práticas de gestão de riscos em alianças. Além disso, verificou-se que as empresas do setor de eletroeletrônicos apresentaram maiores níveis de GCI, enquanto as empresas da indústria automotiva tiveram os menores, demonstrando que empresas desse setor possuem menor propensão a compartir recursos, informações e tecnologia com seus fornecedores. Com relação à percepção de custos de transação e práticas de gestão de riscos, a análise demonstrou que não há diferenças significativas entre os setores estudados. Adicionalmente, os resultados demonstram que as empresas que utilizam ferramentas de gestão de custos, tais como custeio baseado em atividades (ABC) ou custeio alvo, possuem maiores níveis de GCI, o número de fornecedores e o tamanho desses parceiros também influencia na intensidade com que as empresas adotam a abordagem de GCI. Em relação à percepção de custos de transação, os resultados revelam que a experiência dos gestores e do tamanho da companhia influenciam na visão sobre os custos de transação. Já em relação às práticas de gestão de riscos em alianças, os resultados demonstram que as empresas que possuem acordos de ganhos compartilhados com fornecedores tendem a adotar mais intensamente as práticas GRA, além disso, o tamanho do fornecedor e setor de atuação da empresa também influenciam na intensidade com que tais práticas são adotadas. As principais contribuições deste trabalho foram o desenvolvimento de instrumentos para mensuração do nível de adoção de práticas de GCI e GRA, bem como a investigação empíricas sobre a relação entre percepção de GCI, CT e GRA. / This PhD dissertation addresses the relationship between inter-organizational cost management (IOCM), transaction costs (TC), and alliance risk management (ARM) in companies operating in Brazil. The research method consists in applying a survey questionnaire. The scores of IOCM, TC, and ARM were measured having the perception of purchase and supply managers of selected firms as a basis. The sample has 85 valid answers, from 5 sectors of the manufacturing industry (automotive, consumer goods, electronics, chemical, and metallurgy). The results demonstrate a significant association between IOCM and ARM, that is, companies adopting an inter-organizational cost management approach have more emphasis on practices of alliance risk management. Besides, it was found that IOCM and ARM approach do not affect the manager\'s perception about TC, thus, adoption of inter-organizational cost management approach does not increases perception of transaction cost since this approach is combined with practices of alliance risk management. Moreover, it was found that firms from the electronics industry have the highest level of IOCM, while automotive industry firms have the lowest, showing that automotive firms has less likelihoods to share resources, information and technology with suppliers. Regarding perception of transaction cost and alliance risk management, there is no significant difference between the industries studied. Additionally, the research demonstrates that companies using a cost management tool, such as activity-based costing (ABC) or target costing, have a higher level of IOCM, number of suppliers and the size of partners also influences the intensity as firms adopting IOCM approach. Regarding the perception of transaction costs, the results reveal that both manager\'s experience and company size influence the perception of transaction cost. Concerning the practices of alliance risk management, the results demonstrate that the firms having earnings-sharing agreements with suppliers apply more ARM practices, also, the size of suppliers and the industry of the firms influences the intensity as firms adopt practices of alliance risk management. The main contribution of this study was the development of an instrument to measure the level of IOCM and ARM, as well as an empirical investigation of the relationship between perceived level of IOCM, TC and ARM.

This thesis work deals with the volume changes during the solidification of cast irons and peritectic steels. The volume changes in casting metals are related to the expansion and/or contraction of the molten metal during solidification. Often, different types of shrinkage, namely macro- and micro-shrinkage, affect the casting quality. In addition to that, exposure of the metal casting to higher contraction or expansion during the solidification might also be related to internal strain development in samples, which eventually leads to surface crack propagation in some types of steel alloys during continuous casting. In consequence, a deep understanding of the mechanisms and control of the solidification will improve casting quality and production. All of the experiments during the entire work were carried out on laboratory scale samples. Displacement changes during solidification were measured with the help of a Linear Variable Displacement Transformer (LVDT). All of the LVDT experiments were performed on samples inside a sand mould. Simultaneously, the cooling curves of the respective samples during solidification were recorded with a thermocouple. By combining the displacement and cooling curves, the volume changes was evaluated and later used to explain the influence of inoculants, carbon and cooling rates on volume shrinkages of the casting. Hypoeutectic grey cast iron (GCI) and nodular cast iron (NCI) with hypo-, hyper- and eutectic carbon compositions were considered in the experiments from cast iron group. High nickel alloy steel (Sandvik Sanbar 64) was also used from peritectic steel type. These materials were melted inside an induction furnace and treated with different types of inoculants before and during pouring in order to modify the composition. Samples that were taken from the LVDT experiments were investigated using a number of different  methods in order to support the observations from the displacement measurements:  Differential Thermal Analysis (DTA), to evaluate the different phase present; Dilatometry, to see the effect of cooling rates on contraction for the various types of alloys; metallographic studies with optical microscopy; Backscattered electrons (BSE) analysis on SEM S-3700N, to investigate the different types of oxide and sulphide nuclei; and bulk density measurements  by applying Archimedes' principle. Furthermore, the experimental volume expansion during solidification was compared with the theoretically calculated values for GCI and NCI. It was found that the casting shows hardly any shrinkage during early solidification in GCI, but in the eutectic region the casting expands until the end of solidification. The measured and the calculated volume changes are close to one another, but the former shows more expansion. The addition of MBZCAS (Si, Ca, Zr, Ba, Mn and Al) promotes more flake graphite, and ASSC (Si, Ca, Sr and Al) does not increase the number of eutectic cells by much. In addition to that, it lowers the primary austenite fraction, promotes more eutectic growth and decreases undercooled graphite and secondary dendritic arm spacing (SDAS). As a result, the volume expansion changes in the eutectic region. The expansion during the eutectic growth increase with an increase in the inoculant weight percentage. At the same time, the eutectic cells become smaller and increase in number. The effect of the inoculant and the superheat temperature shows a variation in the degree of expansion/contraction and the cooling rates for the experiments. Effective inoculation tends to homogenize the eutectic structure, reducing the undercooled and interdendritic graphite throughout the structure. In NCI experiments, it was found that the samples showed no expansion in the transversal direction due to higher micro-shrinkages in the centre, whereas in the longitudinal direction the samples shows expansion until solidification was complete.   The theoretical and measured volume changes agreed with each other. The austenite fraction and number of micro-shrinkage pores decreased with increase in carbon content. The nodule count and distribution changes with carbon content. The thermal contraction of NCI is not influenced by the variation in carbon content at lower cooling rates. The structural analysis and solidification simulation results for NCI show that the nodule size and count distribution along the cross-sections at various locations are different due to the variation in cooling rates and carbon concentration. Finer nodule graphite appears in the thinner sections and close to the mold walls. A coarser structure is distributed mostly in the last solidified location. The simulation result indicates that finer nodules are associated with higher cooling rate and a lower degree of microsegregation, whereas the coarser nodules are related to lower cooling rate and a higher degree of microsegregation. As a result, this structural variation influences the micro-shrinkage in different parts. The displacement change measurements show that the peritectic steel expands and/or contracts during the solidification. The primary austenite precipitation during the solidification in the metastable region is accompanied by gradual expansion on the casting sides. Primary δ-ferrite precipitation under stable phase diagram is complemented by a severe contraction during solidification. The microstructural analysis reveals that the only difference between the samples is grain refinement with Ti addition. Moreover, the severe contraction in solidification region might be the source for the crack formation due to strain development, and further theoretical analysis is required in the future to verify this observation. / <p>QC 20170228</p>

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2008. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-03-12T12:27:06Z No. of bitstreams: 1 2008_tiago_gandra.pdf: 4024866 bytes, checksum: 3540cf3f3ea76e36028fd0985ef4ab5e (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-17T18:40:54Z (GMT) No. of bitstreams: 1 2008_tiago_gandra.pdf: 4024866 bytes, checksum: 3540cf3f3ea76e36028fd0985ef4ab5e (MD5) / Made available in DSpace on 2013-06-17T18:40:54Z (GMT). No. of bitstreams: 1 2008_tiago_gandra.pdf: 4024866 bytes, checksum: 3540cf3f3ea76e36028fd0985ef4ab5e (MD5) Previous issue date: 2008 / Este trabalho trata de dois instrumentos de suporte à gestão ambiental previstos no Plano Nacional de Gerenciamento Costeiro (PNGC) - o Sistema de Informações Geográficas Costeiras (SIGERCO) e o Zoneamento Ecológico-Econômico Costeiro (ZEEC) - utilizando o Município de Rio Grande (RS) como estudo de caso. Ele consiste na organização e integração de dados no SIGERCO de maneira que este possa auxiliar no desenvolvimento de uma metodologia simples, flexível e replicável para a elaboração do ZEEC. Existe uma forte demanda para que os municípios costeiros elaborem seus ZEEC, mas as experiências anteriores utilizaram metodologias e resultados que não seguem os critérios e classes definidos pelo PNGC. Para a construção do ZEEC é necessária a definição da Unidade Ambiental de Gestão (UAG’s) adequada. Para tal, foram compilados diversos tipos de divisão territorial já realizadas na região. Para a definição das UAG’s foi escolhida a abordagem geomorfológica, baseando-se em experiências anteriores registradas na bibliografia. Os critérios definidos pelo PNGC para o ZEEC são subjetivos, possibilitando uma enorme gama de zoneamentos distintos, dependente dos pesos atribuídos a cada critério e da definição de quebras de classe. Foram avaliados e comparados quatro experimentos de ZEEC segundo as diretrizes do PNGC, bem como um ZEEC obtido com os critérios utilizados em Santa Catarina e o zoneamento aprovado no Plano Ambiental Municipal (PLAM) de Rio Grande. O SIGERCO produzido para o município pode representar um salto na compreensão e difusão de conhecimentos científicos para a tomada de decisões, desde que seja disponibilizado via internet e esteja em constante ampliação e atualização. A metodologia proposta nesta dissertação exige poucos dados para a elaboração do ZEEC (geomorfologia, vegetação, usos dos solos e censo do IBGE), o que possibilita a rápida elaboração ou adequação dos ZEEC’s. A subjetividade da metodologia proposta deve ser o espaço de flexibilidade para a decisão, que deverá ser tomada através de consultas públicas a todos os atores sociais. Apesar de não seguir os critérios e classes propostos, o ZEEM aprovado no PLAM de Rio Grande não apresentou grandes diferenças espaciais de proposição de usos quando comparado ao ZEEC proposto. Portanto, o ZEEM atual deve ser testado na prática, implementado e revisado periodicamente, o que seria uma boa oportunidade a adequação aos critérios propostos no PNGC. / This work dealt with two instruments created by the Brazilian Government to support the environmental management in the context of the Brazilian National Plan for Coastal Management (PNGC), using the city of Rio Grande (RS) as a case study. Such instruments were the Geographical Information System of the Coastal Zone (SIGERCO) and the Coastal Ecological-Economic Zoning (ZEEC). It consisted of the organization and integration of data in the SIGERCO in a manner that can assist the development of a simple methodology for the elaboration of the ZEEC. There is strong demand that coastal cities elaborate their ZEEC; however, previous experiences have used methodologies and results that do not follow the criteria and classification defined in the PNGC. For ZEEC construction, the definition of Environmental Management Units (EMU’s) is necessary. Therefore, diverse types of territorial division already elaborated in the city area were compiled. Geomorphology was chosen for defining the geographical limits of the EMUs, based on previous experiences in literature. The criteria defined by the PNGC for the ZEEC are subjective, making an enormous gamma of distinct zonings possible, depending on the weights attributed to each criterion and the chosen class breaks. In this work, four ZEEC experiments were evaluated and compared, as well as a ZEEC following the State of Santa Catarina zoning and the zoning approved in the Municipal Environmental Plan (PLAM) of Rio Grande. The SIGERCO organized for this city can represent a large improvement in comprehension and diffusion of scientific knowledge to decision-makers. However, it has to be available on the internet, and constantly updated. The ZEEC methodology proposed in this work demands few data for its elaboration, consisting basically of geomorphological and land-use maps and socio-economic data collected by IBGE. This makes possible the fast adequacy of zonings already elaborated and the construction of new ones for the entire Brazilian coast. Moreover, the establishment of criteria weights and class breaks must be carried out through public consultations, involving decision-makers, scientific community and organized civil society. Although it did not follow the established methodology, the ZEEM approved in the PLAM did not present large spatial differences in the uses proposition when compared to the ZEEC. Therefore, the ZEEM must be tested in the real world and periodically be revised. This would be a good opportunity for adjusting it to the criteria considered in the National Plan for Coastal Management.