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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.
1

Research of oxidation influence on the properties of biological base oils / Oksidacijos įtakos biologinės kilmės bazinų alyvų savybėms tyrimas

Kreivaitis, Raimondas 16 November 2011 (has links)
The following tasks were performed in order to achieve the goal of the study: Investigation of the potential of vegetable and animal origin stocks according to tribological properties for production of environmentally friendly base lubricants; Investigation of the influence of accelerated oxidation on tribological and physicochemical properties of rapeseed oil; Investigation of the influence of natural antioxidants on oxidation properties of rapeseed oil; Investigation of the influence of ageing on tribological and physicochemical properties of pure and natural antioxidants modified rapeseed oil; Investigation of the influence of oxidation on corrosiveness of rapeseed oil; Investigation of the influence of oxidation on biodegradability of pure and natural antioxidants modified rapeseed oil. / Darbo tikslui pasiekti buvo sprendžiami šie uždaviniai: Vertinant tribologines savybes ištirti vietinių augalinės ir gyvūninės kilmės žaliavų potencialą aplinkai draugiškų bazinėms alyvoms gaminti; Ištirti pagreitintos oksidacijos įtaką rapsų aliejaus tribologinėms ir fizinėms-cheminėms savybėms; Ištirti natūralių antioksidantų įtaką rapsų aliejaus oksidacinėms savybėms; Ištirti gryno ir natūraliais antioksidantais modifikuoto rapsų aliejaus senėjimo laikant įtaką tribologinėms ir fizinėms-cheminėms jo savybėms; Ištirti oksidacijos įtaką rapsų aliejaus korozinėms savybėms; Ištirti oksidacijos įtaką gryno ir natūraliais antioksidantais modifikuoto rapsų aliejaus biologiniam suirstamumui.
2

Avaliação de plastificantes alternativos em composições de borracha

Souza, Ânderson A. January 2011 (has links)
Nos últimos anos muita atenção tem sido dada a produtos que apresentam em sua composição, substâncias com uso restrito por seu risco potencial ao meio ambiente ou à saúde. A União Européia, inserida ativamente neste contexto, regulamenta requisitos que os fabricantes devem atender para, por exemplo, exportarem seus produtos à Europa. Em artefatos de borracha as maiores restrições são relativas ao uso de óleos plastificantes aromáticos e tipo ésteres ftálicos. Os óleos plastificantes são amplamente utilizados na aditivação de borrachas com o objetivo de melhorar processabilidade, reduzir custos e aperfeiçoar propriedades dos materiais visando suas aplicações. Neste âmbito alguns plastificantes reativos a base de ésteres, alguns óleos minerais e vegetais (renováveis) têm se demonstrado alternativas viáveis aos plastificantes restritos para borracha. Assim, o presente trabalho objetivou a avaliação desses plastificantes (de baixo impacto ambiental e sem restrições à saúde), explorando-se a capacidade reativa, compatibilidade e efeitos nas propriedades da borracha nitrílica hidrogenada, HNBR, e borracha de estireno-butadieno, SBR. As características das composições de HNBR contendo 10 phr e as de SBR contendo 15 phr de plastificante frente à vulcanização foram determinadas a partir das curvas reométricas. Igualmente, determinou-se a viscosidade e a relaxação de tensão destas composições. Os vulcanizados foram caracterizados quanto a sua dureza, resistência à tração, índice de dispersão da carga, densidade, resiliência, deformação permanente à compressão, flexibilidade a baixas temperaturas, comportamento frente ao envelhecimento térmico e inchamento em solvente e óleo IRM 903. Todas as composições contendo os plastificantes foram comparadas a composição sem plastificante (NTP). Nos estudos, verificou-se que o óleo vegetal de mamona in natura é capaz de substituir o plastificante éster de ftalato (DOP) na aplicação em HNBR, observando-se boa compatibilidade com este último. Na SBR os plastificantes Fluibrax Euro 40 (Petrobras), Nytex 4700 (Ninas), Flex NBS 100 (Quantiq) assim como os óleos vegetais de soja e linhaça mostraram-se em condições de substituir os óleos aromáticos restritos. Também, observou-se equivalência de desempenho entre os plastificantes, óleo vegetal de mamona e óleo éster reativo RP1020 (Hall Star) em HNBR curada com peróxido indicando que ambos plastificantes passam por um mecanismo de enxertia com a borracha. / In recent years much attention has been given to products that contain substances with restricted use because of its potential risks to the environment and health. The European Union regulates strongly the requirements that manufacturers must meet, for example, to export their products to Europe. In rubber products, the major constraints are related to the use of aromatic oils and phthalates ester plasticizers as additives. The plasticizers are widely used in rubber in order to improve processability, to reduce costs and to improve properties of materials to their applications. In this context some reactive ester plasticizers, some mineral and vegetable oils (renewable) have demonstrated viable alternatives to the restricted plasticizers for rubber. Thus, this study aimed to evaluate these plasticizers (low environmental impact and no restrictions on health), exploiting its reactive capacity, rubber compatibility and effects on the properties of hydrogenated nitrile rubber, HNBR, and on styrene-butadiene rubber, SBR. The characteristics of the compositions of the HNBR and SBR containing 10 phr and 15 phr of plasticizer, respectively, related to the vulcanization were determined by rheometric analysis. The influence of the plasticizer on the viscosity and stress relaxation were also determined. The cured material were characterized as the hardness, strength, dispersion of the filler, density, rebound, compression set, flexibility at low temperature, brittleness point, heat ageing and swelling behavior in solvent and in IRM 903 oil. All the compositions with plasticizer were compared to the composition without plasticizer (NTP). In this work it was found that the castor vegetable oil in natura has been able to replace the phthalate ester plasticizer (DOP) in HNBR, maintaining good compatibility with the elastomer. In SBR, the plasticizers Fluibrax Euro 40 (Petrobras), Nytex 4700 (Ninas), Flex NBS 100 (QuantiQ), and the vegetables oils soybean and linseed could be properly applied as alternatives to restricted aromatic oils. It was observed very similar behavior between the compounds with the plasticizers RP1020 (reactive) and castor oil. The results of rheometry, acetone extraction and toluene swelling support the hypothesis of the grafting mechanism/oligomers formation for the RP1020 and castor plasticizers in HNBR cured with peroxide, indicating that both plasticizers undergo a mechanism of grafting with the rubber.
3

Avaliação de plastificantes alternativos em composições de borracha

Souza, Ânderson A. January 2011 (has links)
Nos últimos anos muita atenção tem sido dada a produtos que apresentam em sua composição, substâncias com uso restrito por seu risco potencial ao meio ambiente ou à saúde. A União Européia, inserida ativamente neste contexto, regulamenta requisitos que os fabricantes devem atender para, por exemplo, exportarem seus produtos à Europa. Em artefatos de borracha as maiores restrições são relativas ao uso de óleos plastificantes aromáticos e tipo ésteres ftálicos. Os óleos plastificantes são amplamente utilizados na aditivação de borrachas com o objetivo de melhorar processabilidade, reduzir custos e aperfeiçoar propriedades dos materiais visando suas aplicações. Neste âmbito alguns plastificantes reativos a base de ésteres, alguns óleos minerais e vegetais (renováveis) têm se demonstrado alternativas viáveis aos plastificantes restritos para borracha. Assim, o presente trabalho objetivou a avaliação desses plastificantes (de baixo impacto ambiental e sem restrições à saúde), explorando-se a capacidade reativa, compatibilidade e efeitos nas propriedades da borracha nitrílica hidrogenada, HNBR, e borracha de estireno-butadieno, SBR. As características das composições de HNBR contendo 10 phr e as de SBR contendo 15 phr de plastificante frente à vulcanização foram determinadas a partir das curvas reométricas. Igualmente, determinou-se a viscosidade e a relaxação de tensão destas composições. Os vulcanizados foram caracterizados quanto a sua dureza, resistência à tração, índice de dispersão da carga, densidade, resiliência, deformação permanente à compressão, flexibilidade a baixas temperaturas, comportamento frente ao envelhecimento térmico e inchamento em solvente e óleo IRM 903. Todas as composições contendo os plastificantes foram comparadas a composição sem plastificante (NTP). Nos estudos, verificou-se que o óleo vegetal de mamona in natura é capaz de substituir o plastificante éster de ftalato (DOP) na aplicação em HNBR, observando-se boa compatibilidade com este último. Na SBR os plastificantes Fluibrax Euro 40 (Petrobras), Nytex 4700 (Ninas), Flex NBS 100 (Quantiq) assim como os óleos vegetais de soja e linhaça mostraram-se em condições de substituir os óleos aromáticos restritos. Também, observou-se equivalência de desempenho entre os plastificantes, óleo vegetal de mamona e óleo éster reativo RP1020 (Hall Star) em HNBR curada com peróxido indicando que ambos plastificantes passam por um mecanismo de enxertia com a borracha. / In recent years much attention has been given to products that contain substances with restricted use because of its potential risks to the environment and health. The European Union regulates strongly the requirements that manufacturers must meet, for example, to export their products to Europe. In rubber products, the major constraints are related to the use of aromatic oils and phthalates ester plasticizers as additives. The plasticizers are widely used in rubber in order to improve processability, to reduce costs and to improve properties of materials to their applications. In this context some reactive ester plasticizers, some mineral and vegetable oils (renewable) have demonstrated viable alternatives to the restricted plasticizers for rubber. Thus, this study aimed to evaluate these plasticizers (low environmental impact and no restrictions on health), exploiting its reactive capacity, rubber compatibility and effects on the properties of hydrogenated nitrile rubber, HNBR, and on styrene-butadiene rubber, SBR. The characteristics of the compositions of the HNBR and SBR containing 10 phr and 15 phr of plasticizer, respectively, related to the vulcanization were determined by rheometric analysis. The influence of the plasticizer on the viscosity and stress relaxation were also determined. The cured material were characterized as the hardness, strength, dispersion of the filler, density, rebound, compression set, flexibility at low temperature, brittleness point, heat ageing and swelling behavior in solvent and in IRM 903 oil. All the compositions with plasticizer were compared to the composition without plasticizer (NTP). In this work it was found that the castor vegetable oil in natura has been able to replace the phthalate ester plasticizer (DOP) in HNBR, maintaining good compatibility with the elastomer. In SBR, the plasticizers Fluibrax Euro 40 (Petrobras), Nytex 4700 (Ninas), Flex NBS 100 (QuantiQ), and the vegetables oils soybean and linseed could be properly applied as alternatives to restricted aromatic oils. It was observed very similar behavior between the compounds with the plasticizers RP1020 (reactive) and castor oil. The results of rheometry, acetone extraction and toluene swelling support the hypothesis of the grafting mechanism/oligomers formation for the RP1020 and castor plasticizers in HNBR cured with peroxide, indicating that both plasticizers undergo a mechanism of grafting with the rubber.
4

Avaliação de plastificantes alternativos em composições de borracha

Souza, Ânderson A. January 2011 (has links)
Nos últimos anos muita atenção tem sido dada a produtos que apresentam em sua composição, substâncias com uso restrito por seu risco potencial ao meio ambiente ou à saúde. A União Européia, inserida ativamente neste contexto, regulamenta requisitos que os fabricantes devem atender para, por exemplo, exportarem seus produtos à Europa. Em artefatos de borracha as maiores restrições são relativas ao uso de óleos plastificantes aromáticos e tipo ésteres ftálicos. Os óleos plastificantes são amplamente utilizados na aditivação de borrachas com o objetivo de melhorar processabilidade, reduzir custos e aperfeiçoar propriedades dos materiais visando suas aplicações. Neste âmbito alguns plastificantes reativos a base de ésteres, alguns óleos minerais e vegetais (renováveis) têm se demonstrado alternativas viáveis aos plastificantes restritos para borracha. Assim, o presente trabalho objetivou a avaliação desses plastificantes (de baixo impacto ambiental e sem restrições à saúde), explorando-se a capacidade reativa, compatibilidade e efeitos nas propriedades da borracha nitrílica hidrogenada, HNBR, e borracha de estireno-butadieno, SBR. As características das composições de HNBR contendo 10 phr e as de SBR contendo 15 phr de plastificante frente à vulcanização foram determinadas a partir das curvas reométricas. Igualmente, determinou-se a viscosidade e a relaxação de tensão destas composições. Os vulcanizados foram caracterizados quanto a sua dureza, resistência à tração, índice de dispersão da carga, densidade, resiliência, deformação permanente à compressão, flexibilidade a baixas temperaturas, comportamento frente ao envelhecimento térmico e inchamento em solvente e óleo IRM 903. Todas as composições contendo os plastificantes foram comparadas a composição sem plastificante (NTP). Nos estudos, verificou-se que o óleo vegetal de mamona in natura é capaz de substituir o plastificante éster de ftalato (DOP) na aplicação em HNBR, observando-se boa compatibilidade com este último. Na SBR os plastificantes Fluibrax Euro 40 (Petrobras), Nytex 4700 (Ninas), Flex NBS 100 (Quantiq) assim como os óleos vegetais de soja e linhaça mostraram-se em condições de substituir os óleos aromáticos restritos. Também, observou-se equivalência de desempenho entre os plastificantes, óleo vegetal de mamona e óleo éster reativo RP1020 (Hall Star) em HNBR curada com peróxido indicando que ambos plastificantes passam por um mecanismo de enxertia com a borracha. / In recent years much attention has been given to products that contain substances with restricted use because of its potential risks to the environment and health. The European Union regulates strongly the requirements that manufacturers must meet, for example, to export their products to Europe. In rubber products, the major constraints are related to the use of aromatic oils and phthalates ester plasticizers as additives. The plasticizers are widely used in rubber in order to improve processability, to reduce costs and to improve properties of materials to their applications. In this context some reactive ester plasticizers, some mineral and vegetable oils (renewable) have demonstrated viable alternatives to the restricted plasticizers for rubber. Thus, this study aimed to evaluate these plasticizers (low environmental impact and no restrictions on health), exploiting its reactive capacity, rubber compatibility and effects on the properties of hydrogenated nitrile rubber, HNBR, and on styrene-butadiene rubber, SBR. The characteristics of the compositions of the HNBR and SBR containing 10 phr and 15 phr of plasticizer, respectively, related to the vulcanization were determined by rheometric analysis. The influence of the plasticizer on the viscosity and stress relaxation were also determined. The cured material were characterized as the hardness, strength, dispersion of the filler, density, rebound, compression set, flexibility at low temperature, brittleness point, heat ageing and swelling behavior in solvent and in IRM 903 oil. All the compositions with plasticizer were compared to the composition without plasticizer (NTP). In this work it was found that the castor vegetable oil in natura has been able to replace the phthalate ester plasticizer (DOP) in HNBR, maintaining good compatibility with the elastomer. In SBR, the plasticizers Fluibrax Euro 40 (Petrobras), Nytex 4700 (Ninas), Flex NBS 100 (QuantiQ), and the vegetables oils soybean and linseed could be properly applied as alternatives to restricted aromatic oils. It was observed very similar behavior between the compounds with the plasticizers RP1020 (reactive) and castor oil. The results of rheometry, acetone extraction and toluene swelling support the hypothesis of the grafting mechanism/oligomers formation for the RP1020 and castor plasticizers in HNBR cured with peroxide, indicating that both plasticizers undergo a mechanism of grafting with the rubber.
5

Hydraulic fluids with new, modern base oils – structure and composition, difference to conventional hydraulic fluids; experience in the field

Bock, Wolfgang, Braun, Jürgen, Schürrmann, Tobias 28 April 2016 (has links) (PDF)
The paper describes the comparison and the difference of modern hydraulic fluids compared to conventional hydraulic fluids. A comparison of different base oil groups, solvent neutrals, group I and comparison with hydrotreated/hydroprocessed group II and/or group III base oils is presented. The influence on oxidation stability, elastomer compatibility, carbon distribution and physical properties is outlined.
6

AvaliaÃÃo em unidade piloto da desativaÃÃo de catalisadores industriais de hidrotratamento. / Evaluation in pilot plant of the deactivation of industrial hydrotreating catalysts

Marcelo Ramalho Amora Junior 10 December 2015 (has links)
PetrÃleo Brasileiro S/A / O objetivo principal à determinar a atividade catalÃtica residual e as causas da desativaÃÃo de amostras de catalisadores de uma unidade de HDT de lubrificantes. Foram realizadas corridas em unidade piloto, caracterizaÃÃo dos catalisadores e coletados dados do histÃrico operacional da unidade industrial. A atividade catalÃtica foi determinada atravÃs das conversÃes das reaÃÃes de HDA, HDS e HDN bem como pelos parÃmetros cinÃticos aparentes de um modelo de lei das potÃncias e lei de Arrhenius. Os catalisadores dos leitos principais de entrada e saÃda dos reatores industrial foram os mais desativados e o menos desativado o do leito intermediÃrio sendo estabelecida a seguinte ordem de atividade catalÃtica residual: R1L3 (meio) > R1L2 (topo)  R2L2 (fundo). Os resultados de teor e caracterÃsticas do coque, contaminantes e propriedades texturais sugerem que mecanismos distintos tenham causado a desativaÃÃo desses catalisadores: deposiÃÃo de metais e deposiÃÃo de coque. Os mecanismos de desativaÃÃo foram fortemente influenciados pelo posicionamento das amostras no interior do leito catalÃtico. No inÃcio do leito, a contaminaÃÃo por metais (notadamente Si e As) revelou-se o principal mecanismo de desativaÃÃo. Jà no final do leito, a deposiÃÃo de coque foi o mecanismo preponderante e a temperatura de reaÃÃo identificada como a principal causa para o maior envelhecimento do coque. / The main objective of this work is to study the residual catalyst activity and the mechanisms of deactivation of catalyst from a lube-oil hydroprocessing industrial unit. In order to accomplish this, pilot plant tests were carried out followed by spent catalysts characterization. The residual catalytic activity was determined by HDA, HDS and HDN conversions and adjusted by a power law apparent kinetic model. Pilot plant tests revealed different levels of residual activity for spent catalyst samples. Catalyst samples taken from the first and last of the five catalytic beds showed higher deactivation than others. Catalyst characterization results pointed out two mechanisms as the main reason for the catalytic deactivation through the industrial reactor: poisoning by metal deposition (mainly Si and As) and coke deposition. Poisoning was the main deactivation mechanism for the first bed spent catalyst sample, while coke deposition was predominant at the last catalytic bed sample. Reactor temperature was identified as the most important operational parameter considering coke aging.
7

Hydraulic fluids with new, modern base oils – structure and composition, difference to conventional hydraulic fluids; experience in the field

Bock, Wolfgang, Braun, Jürgen, Schürrmann, Tobias January 2016 (has links)
The paper describes the comparison and the difference of modern hydraulic fluids compared to conventional hydraulic fluids. A comparison of different base oil groups, solvent neutrals, group I and comparison with hydrotreated/hydroprocessed group II and/or group III base oils is presented. The influence on oxidation stability, elastomer compatibility, carbon distribution and physical properties is outlined.
8

MASS SPECTROMETRY IONIZATION STUDIES AND METHOD DEVELOPMENT FOR THE ANALYSIS OF COMPLEX MIXTURES OF SATURATED HYDROCARBONS AND CRUDE OIL

Jeremy M Manheim (6594134) 17 April 2020 (has links)
<p>Crude oil is a mixture of hydrocarbons so complex that it is predicted to comprise as many compounds as there are genes in the human genome. Developing methods to not only recover crude oil from the ground but also to convert crude oil into desirable products is challenging due to its complex nature. Thus, the petroleum industry relies heavily on analytical techniques to characterize the oil in reservoirs prior to enhanced oil recovery efforts and to evaluate the chemical compositions of their crude oil based products. Mass spectrometry (MS) is the only analytical technique that has the potential to provide elemental composition as well as structural information for the individual compounds that comprise petroleum samples. The continuous development of ionization techniques and mass analyzers, and other instrumentation advances, have primed mass spectrometry as the go-to analytical technique for providing solutions to problems faced by the petroleum industry. The research discussed in this dissertation can be divided into three parts: developing novel mass spectrometry-based methods to characterize mixtures of saturated hydrocarbons in petroleum products (Chapters 3 and 5), exploring the cause of fragmentation of saturated hydrocarbons upon atmospheric pressure chemical ionization to improve the analysis of samples containing these compounds (Chapter 4), and developing a better understanding of the chemical composition of crude oil that tightly binds to reservoir surfaces to improve chemically enhanced oil recovery (Chapter 6). </p>

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