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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

The use of solid state imagers as X-ray detectors

Magorrian, Brian Geoffrey January 1989 (has links)
No description available.
2

Structure Pharmaceutics Based on Synchrotron Radiation X-Ray Micro- Computed Tomography: From Characterization to Evaluation and Innovation of Pharmaceutical Structures

Yin, Xianzhen January 2016 (has links)
Drug delivery systems (DDS) are essentially pharmaceutical products for human therapy, typically involving a mixture of active ingredients and excipients. Based upon quantitative characterization of structure, the thesis introduces the concept of classifying the architecture of DDS into four levels by their spatial scale and the life time period. The primary level is recognised as the static structure of the whole dosage form with a size from μm to cm with the final structure generated by formulation design. The secondary level categorises the structures of particles or sub-units to form a DDS with sizes from nm to mm as key units in processing such as mixing, grinding, granulation and packing; The tertiary level represents the dynamic structures of DDS during the drug release phase in vitro or in vivo incorporating the structure size range from nm to mm, which undergo changes during dissolution, swelling, erosion or diffusion. The spatial scale for the quaternary level is defined as the meso or micro scale architecture of active and non-active molecules within a DDS with sizes from Å to μm for the molecular structure of drug and excipients. Methods combining X-ray tomography, image processing, and 3D reconstructions have been devised and evaluated to study systematically pharmaceutical structures and correlate them with drug release kinetics of DDS. Based on the quantitative structural information of pharmaceutical intermediates and dosage forms, it is possible now to correlate structures with production processing, behaviour and function, and the static and dynamic structures of DDS with the release kinetics. Thus, a structure-guided methodology has been established for the research of DDS. / Chinese Academy of Sciences
3

Insights of Taste Masking from Molecular Interactions and Microstructures of Microspheres

Guo, Zhen January 2017 (has links)
The effects of taste masking are determined by interactions between drug and excipients as well as the microstructures of the particulate drug delivery systems (DDS). Cyclodextrin (CD) is a widely used taste masking agent, to which the relationship between kinetic parameters (Ka and Kd) of a drug and taste masking remains unexplored, which is investigated for the first time in this study. A data base of the kinetic parameters for drug-CD was established by Surface Plasmon Resonance Imaging (SPRi) and High Performance Affinity Chromatography (HPAC). Combined with the electronic tongue, Ka and Kd based models for the taste masking effect of HP-β-CD were successfully established and applied to the prediction of taste masking effects. Paracetamol was used as a model drug for taste masking formulation optimization. As well as drug release the microstructure of solid DDS has considerable influence on drug taste. The microstructure of lipid microspheres and the molecular distribution of drug and excipients in lipid microspheres were investigated by Synchrotron radiation-based micro-computed tomography (SR-μCT) and Synchrotron radiation-based Fourier-transform infrared spectromicroscopy (SR-FTIR), respectively. The results demonstrated that the polymeric formulation components as well as shape and particle size of the drug were the key factors to taste masking of paracetamol by inhibiting bust release thereby reducing the interaction intensity of the bitterness. The FTIR absorption spectra confirmed the deposition and formation of chitosan and gelatin films on the drug microsphere surface by layer-by-layer coating. In conclusion, this research demonstrates the molecular kinetic basis of CD taste-masking as well as microstructural basis of particle systems for bitter taste masking.
4

An investigation, using synchrotron radiation and other techniques, of the composition of San rock art paints and excavated pigments from Maqonqu shelter, and comparative paint data from three other sites in KwaZulu-Natal, South Africa.

Escott, Boyd John. January 2011 (has links)
This study aimed to: 1) characterise the individual San parietal art rock art paint colours; 2) relate paint compositions to erosion susceptibility; 3) determine if paint pigments can be related to pigment samples excavated from a Shelter deposit, and/or a variety of field samples; and 4) determine if paint samples from geographically distinct sites can be distinguished on their composition. A combination of mineralogical (X-ray diffraction (XRD), synchrotron micro-XRD (μ-XRD)) and chemical (energy dispersive X-ray micro-analysis (EDX), X-ray fluorescence spectrometry (XRF), and synchrotron micro-XRF (μ-XRF)) analytical techniques were used. Maqonqo Shelter (MQ), 35 km south-east of Dundee, KwaZulu-Natal, South Africa, was the primary study site chosen as it contained both a large number of paintings, as well as a large deposit. Thirty paint (of various colours) and 3 blank wall samples were collected using Silver Mylar tape and analysed using a combination of EDX, μ-XRD and μ-XRF techniques. Sixty two large (> 2.5 g) ‘ochre’ pieces were selected from the upper three layers of the deposit and analysed using XRD, XRF and EDX. A further 63 small pieces (< 2.5 g) were analysed using μ-XRD and μ-XRF techniques. To compare the MQ paint samples with potential source materials, three distinct sample sets were collected. The first included samples of the Shelter wall and surface rocks located near the painted panel (analysed by XRD, XRF and EDX). A second sample set of 17 samples was collected from the surrounding landscape (± 3 km radius of MQ; analysed by XRD and XRF). Their selection was based on ease of accessibility, degree of pulverulence, and perceived Fe content i.e., red and/or yellow colouration. No white sources were found. A third set of 11 samples (obtained from six sites, analysed using XRD and XRF) was collected within ± 50 km distance of the Shelter. Their selection was based on old mining survey reports that detailed the location of Fe ore outcrops. Paint samples from three additional shelters i.e., Fergies Cave (FC), Giants Castle Game Reserve, central Drakensberg; Sheltered Vale (SV), Mount Currie District, south-western KwaZulu-Natal; and Twagwa Shelter (TW), Izingolweni District, southern KwaZulu-Natal, were collected to compare paint composition over distance. Site selection was determined according to the following criteria: 1) the shelters had to reside a significant distance away from the primary site so as to minimise any possible interaction that might have existed between the authors of the respective artworks (each site is at least 100 km distant from the other); 2) each had to be located upon a distinct geological formation so that external influences from different regions, and their possible affects on the paint samples, could be noted; and 3) the climatic regimes of each of the shelters should be relatively distinct. Fifteen paint and nine blank wall samples were collected from the three shelters (three each of red, white and blank samples; analysed using EDX, μ-XRD and μ-XRF), with the exception that no white samples were collected from FC. In total, 673 EDX, 212 μ-XRD, 378 μ-XRF, 98 XRD, 98 XRF and 6 ICP-MS traces were produced and analysed. Due to the extremely heterogeneous nature of the paint samples at the microii scale, the more generalised EDX reduced window scans were used as the basis of the paint samples’ characterisation, with the data obtained from the more precise μ-XRD and μ-XRF techniques providing additional supportive information. Irrespective of colour, almost all of the MQ paint samples had elevated Ca contents that tended to increase in the order of black < orange £ red and yellow < pink < white. The predominant Ca-based mineral was gypsum, although Ca-oxalates, whewellite and weddellite, were also present. The blank samples collected from MQ also had high gypsum content, but no Ca-oxalate. It is thus proposed that the Ca-oxalates formed after the painting event and were derived from the original paint constituents. The white pigments consisted of gypsum (dominant), anhydrite, bassanite and whewellite, or a combination thereof. Whewellite increased within increasing paint depth, while gypsum showed the reverse trend. This indicates that, whilst both gypsum and whewellite were originally present within the original paint pigment, additional gypsum has been added via secondary evaporite deposition. Although initially considered to be sourced along with the gypsum, another potential whewellite source is organic additives. The most likely source for the white pigments would be precipitates found on sandstone walls of shelters near MQ. Of more immediate importance, however, is that the pigments, being gypsum based, are water-soluble and thus susceptible to erosion. Most of the orange paints had an elevated Al content and contained gibbsite, suggesting bauxitic material associated with locally sourced dolerite within the Ecca Series within KwaZulu-Natal (as evidenced by their respective Ti levels). Two samples were so similar that it is likely that the same pigment was utilised in the creation of both images. Two samples did not contain high Al contents, however, indicating that they were probably sourced from the soft, ochreous material found within local Fe nodules. A consistent combination of goethite and haematite, together with a low Al and elevated Ti content, indicate that the yellow and red samples were probably sourced from Fe nodules found locally, the red samples differing from the yellow pigments primarily in their higher haematite content. A low Si and relatively low Fe content discounts red sands/clays and Fe-ores as sources of the red pigments. The red samples were ‘thinner’ than the other samples with quartz contents comparable to those of the blank samples. The thin nature of the red paints, the erratic distribution of whewellite upon the paint surfaces, the dominance of gypsum and, to a certain extent quartz, all strongly suggest that the red paints are at least partly absorbed into the surface of the Shelter wall. This, together with the strong staining ability of haematite, is probably the most important reason that the red pigments have outlasted images painted in other colours. It may also account for the high degree of variability found within the red paint dataset, though age differences between the sampled images could also be a contributing factor. The single dark red paint sample, except for an elevated Mn content, was very similar in many ways to the red paint samples analysed. The only readily available pigment source identified that had both low Al and high Fe and Mn contents, was plinthite. The pink samples represented the ‘middleiii ground’ between the red and white paints, suggesting that this colour was the result of a blending of the two. The black paint sample had the highest recorded Fe content of the entire paint dataset. A high Mn and relatively low Al content suggest that a soft inner core of an Fe nodule was used in its manufacture. The presence of maghemite and a dark colouration strongly suggest that the manufacture also involved calcination. The initial distinction between the paint and excavated samples was that the former all exhibited elevated Ca and S values due to the deposition of secondary evaporite minerals. Even when taking these additional deposits into account, however, the two datasets still remained distinct indicating that the excavated materials sampled were not utilised in the manufacture of the MQ paints. A potential exception concerned the orange paint samples, which were similar in composition to both doleritic samples from deeper excavated layers and the local (weathered doleritic samples) and distant (bauxite samples) field samples. Whilst weathered dolerite/bauxitic material was clearly the source of the orange pigments, a more detailed investigation is needed to find a precise location. No other relationships between the paint pigments and the excavated pigments and field samples were established. A comparison of the blank samples from all four study sites showed that the techniques used could distinguish between different sites despite sampling the smallest and, relatively speaking, poorest quality samples. The FC blank samples had elevated C and Ca contents (associated with Caoxalates). The conditions within this Shelter favour the formation of weddellite and whewellite, the former not typically found at the other three sites. In addition, low K, Si and Al contents (often associated with sandstone matrix minerals) indicate that the surface of the relatively dense, compact Cave sandstone is more resistant to physical erosion compared to the other sites, and/or FC shelter experiences a high amount of secondary deposition, with the result that a majority of the samples are composed of evaporite minerals. The SV samples were composed primarily of the evaporite-type minerals, with only minor sandstone ‘contamination’ indicated by quartz and kaolinite. The quartz content, whilst not always high, was present in most of the samples analysed, possibly indicating a greater amount of more uniform surface erosion (relative to the other sites). The TW blank samples were distinct from the other shelters’ as they contained no Ca-based minerals but did contain the very rare mineral schlossmacherite. A comparison of the paint colours also revealed differences between the different shelters. Whilst the white samples from SV and MQ are dominated by whewellite and gypsum (minerals probably present within the pigments when they were applied), the presence of quartz, sanidine and apatite in the SV samples indicated a degree of shelter wall ‘contamination’, with anhydrite, bassanite and glushinskite suggesting climatic variations that favoured various evaporite depositional regimes. The TW white paint contained minimal secondary deposited minerals common in the other shelters. The one mineral that is dominant within the TW samples is minamiite. As this mineral was not identified in any of the blank samples, it is likely that this mineral originates from the original pigment source. The TW white paints also contained 10 to 40 times more Zn than those recorded for any of the other paint samples. This was possibly present within the structure of greigite. The red SV samples could be distinguished from MQ red samples by the presence of wall ‘contaminants’ in a manner similar to that described for the white samples. The TW samples indicate a change in pigment source and/or manner of paint manufacturing technique, for these red samples contained minamiite. This mineral is white and thus its selection could not have been based on colour but rather it must represent a paint additive. With the exception of only one sample from TW, no goethite was found within any of the red samples collected from the three additional sites indicating a different haematite source to that of MQ. An interesting facet of this study, although not directly addressed, concerns what the results do not show with respect to the compositional nature of the pigments analysed. Most texts available today list a number of pigment sources stated to have been utilised in the manufacture of the San parietal rock art. This study has shown that very few of these potential sources were utilised within the four shelters investigated. In addition, this study has also highlighted the presence of minerals about which little is known, yet which appear to be commonly associated with parietal rock art. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
5

Monitoramento e avaliação da emissão de dutos e fontes estacionarias de industrias ceramicas por meio de metodo potenciometrico e fluorescencia de raios X / Monitoring and evaluation of ducts and stationary source emissions from ceramic industries by potntiometry and X-ray fluorescence methods

Fonseca, Roney Jose da 31 August 2007 (has links)
Orientador: Silvana Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-11T08:53:13Z (GMT). No. of bitstreams: 1 Fonseca_RoneyJoseda_M.pdf: 1481408 bytes, checksum: 7f9822fbb599c31623b7b04f50171593 (MD5) Previous issue date: 2007 / Resumo: O objetivo deste trabalho foi monitorar e avaliar a emissão de fluoreto e de metais de dutos e fontes estacionárias de indústrias cerâmicas da região do Pólo Cerâmico de Santa Gertrudes (SP). Nos últimos anos houve um crescimento das empresas neste setor, causando reflexos ambientais nesta região responsável por 60% da produção de pisos esmaltados. O principal causador destes danos é o flúor na forma de fluoreto gasoso e ácido fluorídrico, comumente encontrado no solo e na argila utilizada na fabricação de pisos e artefatos cerâmicos. No período de 2004 a 2007 foram coletadas amostras dos gases emitidos por diversas indústrias cerâmicas desta região. Os compostos a base de flúor foram analisados por potenciometria e alguns metais pela técnica de fluorescência de raios X por reflexão total com radiação síncrotron. Altas concentrações de elementos como Cromo, Níquel e Chumbo foram observadas nas amostras analisadas e, em valores superiores aos permitidos pela legislação. No que se refere à emissão de fluoreto total foi verificado que 61,5% das empresas monitoradas apresentaram valores de emissão acima do permitido (5,0 mg/Nm3). Foi verificado ainda que o fluoreto foi emitido principalmente na forma de fluoreto gasoso. Desta forma a problemática ambiental na região de Santa Gertrudes não está associada apenas à emissão de flúor, mas também está relacionada à presença de metais pesados presentes em altas concentrações nas emissões atmosféricas provenientes do setor cerâmico / Abstract: The purpose of this work was monitoring and evaluation the emissions of fluoride and metals of ducts and stationary sources from ceramics industries of Santa Gertrudes region (SP). In recent years there had been a growth of companies in this sector, causing environmental repercussions in this region responsible for 60% of the production of porcelain tiles. The main cause of these damages is fluorine as fluoride gaseous and fluoridric acid, commonly found in soil and clay used in the manufacture of ceramic artifacts. During 2004 until 2007 gaseous samples were collected in different industries. The fluorine compounds were analyzed by potentiometry method and some metals by X-ray fluorescence analysis. High concentrations of Chromium, Nickel and Lead were observed in the samples and the values were higher than the permitted by the Brazilian legislation. In relation to fluoride emission 61,5% of the industries monitored showed values above the established by the legislation (5.0 mg/Nm3). In this way the environmental pollution in Santa Gertrudes region was not associated just to fluorine emission but also with the heavy metals present in high concentrations in the atmospheric emissions from stationary sources of ceramic industries / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil
6

Avaliação de metais pesados em emissões atmosfericas de industria automotiva por fluorescencia de raios X / Evaluation of the heavy metals in the atmospheric emissions of the automotive industry by SR-TXRF

Weber Neto, Jose 31 August 2007 (has links)
Orientador: Silvana Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-11T18:03:07Z (GMT). No. of bitstreams: 1 WeberNeto_Jose_M.pdf: 3765791 bytes, checksum: d918dd0a186ccff6f6dfa814697be0f7 (MD5) Previous issue date: 2007 / Resumo: A qualidade do ar está diretamente à qualidade de vida da sociedade. Nos últimos anos vários episódios de poluição nos grandes centros urbanos, bem como as doenças causadas pela baixa qualidade do ar têm feito com que os órgãos governamentais estabeleçam padrões de qualidade do ar e também para as emissões atmosféricas que geralmente são as responsáveis pela poluição atmosférica. O presente estudo tem como objetivo a determinação de metais pesados e outros elementos (Bário, Bromo, Cálcio, Chumbo, Cloro, Cobre, Cromo, Estrôncio, Ferro, Manganês, Níquel, Potássio, Silício, Titânio e Zinco), nos poluentes atmosféricos gerados em uma indústria automotiva localizada em Engenheiro Coelho no interior do estado de São Paulo. Os procedimentos adotados para a execução das amostragens e o preparo das amostras foram baseados nas normas definidas pela Companhia de Tecnologia de Saneamento Ambiental (CETESB) e, também pela Agência de Proteção Ambiental Americana (EPA). As análises foram realizadas pela técnica de Fluorescência de Raios X por Reflexão Total com Radiação Síncrotron (SR-TXRF) no Laboratório Nacional de Luz Síncrotron em Campinas (SP). Os resultados obtidos apresentaram concentrações na faixa de 30 mg/Nm³ para Zinco, Ferro, Bário, Cálcio e Potássio, enquanto que os outros elementos apresentaram concentrações próximas a 1 mg/Nm³. A técnica analítica apresentou limites de detecção bem inferiores (cerca de 1000 vezes) aos valores estabelecidos nas Resoluções CONAMA 264/1999 e SEMA 041/2002, que estabelecem valores máximos permitidos para emissões atmosféricas / Abstract: The air quality has a direct link with the life quality society, lately, a large number of cases of air pollution have been happening in the great urban centers, as well as diseases caused by the poor air quality. These facts have forced the government organs to create standards for the air regulations and also for the atmospheric emissions that generally are the main responsible for the air quality alterations. This study had as goal the determination of heavy metals and other elements (Barium, Bromine, Calcium, Lead, Chlorine, Copper, Chromium, Strontium, Iron, Manganese, Nickel, Potassium, Silicon, Titanium and Zinc) in the atmospheric pollutants generated by an automotive industry located in Engenheiro Coelho city, São Paulo State, Brazil. The sampling and sample preparation procedures were based on methods established by Company of Technology of Environmental Sanitation (CETESB L9.234) and also by the Environmental Protection Agency (EPA - Method 29). The analysis was performed at XRF Beamline (D09B-XRF) in the Synchrotron Light Source Laboratory (Campinas/SP). For zinc, iron, barium, calcium, potassium the values obtained were in the range of 30 mg/Nm³ and for other elements the concentrations were approximately 1 mg/Nm³. The analytical technique employed presented detection limits much smaller (1,000 times) than maximum permissive values established by Brazilian legislations (CONAMA 264/1999 and SEMA 041/2002) / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil
7

Quantificação de metais em aguas e sedimentos do reservatorio Billings por fluorescencia de raios X com reflexão total e radiação Sincrotron (SR-TXRF) / Quantification of metals in water and sediments of the Billlings dam by Synchronton radiation total reflection X-Ray fluorescence (SR-TXRF)

Sampaio, Sergio Arnaud 26 February 2007 (has links)
Orientador: Silvana Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-10T23:35:00Z (GMT). No. of bitstreams: 1 Sampaio_SergioArnaud_M.pdf: 1857794 bytes, checksum: b5584970c1ca196d93e07f5d3ea81396 (MD5) Previous issue date: 2007 / Resumo: A Represa Billings é o maior reservatório de água da região metropolitana de São Paulo, com aproximadamente 100 km² em espelho de água. Sua bacia hidrográfica ocupa mais de 500km² em seis municípios da região. Ao seu redor concentra-se o maior parque industrial da América do Sul e somente suas margens são ocupadas por quase um milhão de habitantes. A qualidade de suas águas é, portanto, motivo constante de preocupação de toda a sociedade. Neste trabalho aplica-se a Espectrometria de Fluorescência de Raios X, com Reflexão Total e excitação por Radiação Síncrotron (SR-TXRF), para a identificação e quantificação de metais em águas e sedimentos da Represa Billings. Foram quantificados os metais Cr, Ni, Cu, Zn e Pb, freqüentemente investigados em trabalhos na área ambiental, já que são largamente usados em processos industriais e estão presentes em vários produtos de consumo doméstico. Para o trabalho de campo, foram coletadas amostras em dezoito pontos, incluídas as margens e a porção central da represa, localizados em regiões com ocupação residencial e industrial, como também em regiões preservadas, próximos de pontos de monitoramento adotados pela Companhia de Tecnologia de Saneamento Ambiental do Estado de São Paulo (CETESB). As amostras de água e de sedimentos, bem como as amostras certificadas e padrões, foram analisadas no Laboratório Nacional de Luz Síncrotron ¿ LNLS situado no pólo de alta tecnologia, em Campinas-SP. Foi estabelecida uma comparação entre as concentrações de metais obtidas e os valores de referência para águas e para sedimentos, recomendados pela legislação em vigor. Os resultados obtidos indicam concentrações acima dos valores permitidos para o cobre, generalizada para todos os locais de amostragem, como também para o chumbo na grande maioria desses locais. Os demais metais estudados também apresentaram concentrações acima do permitido para alguns dos pontos de amostragem. O trabalho destaca as vantagens e os aspectos relevantes da técnica de análise (SR-TXRF), considerada como não destrutiva e com baixos limites de detecção (partes por bilhão). Outras vantagens são: a sensibilidade analítica para uma ampla faixa de elementos, com um preparo simples e rápido de amostras e facilidade de operação, e que por isso tem apresentado grande desenvolvimento nos últimos anos, com crescente aceitação da comunidade científica. A finalidade de contexto social é contribuir para a preservação dos mananciais locais e o aproveitamento racional de suas águas / Abstract: The Billings dam is the largest water reservatory in the metropolitan region of Sao Paulo, with approximately 100 km2 of area. Its watershed takes up more than 500 km2 in 6 counties of the region. Around the dam is located the largest industrial region of South America and only its borders have about 1 million inhabitants. The water quality is a constant concern to society. On this study, it is applied the synchrotron radiation total reflection X-ray fluorescence (SRTXRF) analysis for identification and quantification of metals in water and sediments of the Billings dam. Metals such as Cr, Ni, Cu, Zn and Pb were analyzed and investigated by environmental work tasks, as they are largely used in industrial processes and are present in various domestic consumers¿ products. As far as experimental work, samples were collected in 18 locations, including the borders and in the central part of the dam, which were located in both residential and industrial regions, as well as in preserved regions, near the places where monitoring was adopted by the Technology and Environmental Company of São Paulo State (CETESB). The water and sediment samples, as well as the certified ones were analyzed in the Brazilian Synchrotron Light Laboratory (LNLS) located in the high technology pole in Campinas, SP. A comparison was established between the metal concentration obtained and the reference values for water and sediments, recommended by Brazilian laws. The results registered a concentration higher than permissive values for Cu, generalized to all sample locations, as well as to Pb in the majority of these places. Other metals studied also showed a concentration higher than permissive values in some points. The job features the advantages and relevant aspects of the SR-TXRF technique. Advantages as not destructive, with low detection limits, high sensitivity for several elements, simple and quick sample preparation, ease operation among others) that shows great development in the past years, with a growing acceptance in the scientific community. The purpose within the social context is to contribute to the local water sources preservation and the rational usage of its waters / Mestrado / Recursos Hidricos / Mestre em Engenharia Civil
8

Transformações de fase associadas ao processamento termomecânico do aço inoxidável supermartensítico 12Cr/6Ni/2Mo/0,1Ti / Phase transformations related to the thermomechanical processing of a 12Cr/6Ni/2Mo/0,1Ti supermartensitic stainless steel

Escobar Atehortua, Julian David, 1988- 23 August 2018 (has links)
Orientadores: Paulo Roberto Mei, Antonio Jose Ramirez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T10:44:00Z (GMT). No. of bitstreams: 1 EscobarAtehortua_JulianDavid_M.pdf: 12651878 bytes, checksum: f83be91a80d6364b37f33a45ae5d0539 (MD5) Previous issue date: 2013 / Resumo: Neste trabalho foram estudadas as modificações metalúrgicas provocadas por tratamentos térmicos e soldagem por atrito com pino não consumível SAPNC do aço inoxidável supermartensítico AISM 12Cr/6Ni/2Mo/0,1Ti. As chapas de AISM foram fornecidas após laminação a quente e recozimento, com propriedades mecânicas e microestrutura fora do estabelecido pelos requisitos técnicos de controle de qualidade de materiais usados na indústria de transporte de petróleo e gás. Foi utilizada uma metodologia experimental que se consistiu em duas frentes de estudo: 1) Uso de tratamentos térmicos para reproduzir as condições microestruturais empregadas industrialmente; 2) Desenvolvimento de parâmetros de processamento superficial e soldagem de juntas por atrito. Para reproduzir as condições microestruturais das chapas usadas em campo foram realizados diferentes revenimentos intercríticos, em patamares de 610, 625, 650, 670, 700 e 720 °C durante 2,5 horas. Para estudar a cinética de transformação de fases foi usado um simulador termomecânico Gleeble 3S50¿ acoplado a uma fonte de radiação síncrotron, na instalação XTMS pertencente ao Laboratório Nacional de Luz Síncrotron (LNLS). Para o desenvolvimento de parâmetros de processamento e soldagem por atrito foi utilizado um equipamento dedicado para SAPNC no Laboratório Nacional de Nanotecnologia. Os estudos foram feitos empregando uma ferramenta de compósito de nitreto de boro cúbico policristalino com matriz metálica da liga de tungstênio-rênio (25% Re) na forma de pino cônico com rosca, medindo entre 9,2 e 9,5 mm de comprimento e ombro convexo de 25 mm de diâmetro. Foram avaliadas velocidades de rotação na faixa entre 200 e 400 RPM, e velocidades de avanço entre 75 e 100 mm.min-1. Foram reproduzidas as condições de dureza e fração de fases de uma tubulação comercial de AISM, mediante revenimentos intercríticos. A melhor temperatura de revenimento intercrítico foi 610°C, pois conseguiu gerar uma matriz de martensita revenida, com presença de 15% de Foi possível obter um processamento com bom acabamento e livre de defeitos internos, usando 250 RPM e 100 mm.min-1. Para a soldagem de dois passes de juntas de chapas de 17,9 mm de espessura, a melhor combinação de parâmetros foi 300 RPM e 100 mm.min-1. Para os dois estados de fornecimento (recozido; temperado e revenido), a zona misturada consistiu de blocos martensita nova com refinamento progressivo de grão em direção à raiz dos cordões. Foram identificadas 3 zonas termicamente afetadas (ZTA) em relação às 5 que ocorrem na soldagem a arco. Não foram encontradas as ZTAs i e ii (de alta temperatura), suprimindo completamente a precipitação de ferrita delta. A ZTA iii (de austenitização completa) era totalmente constituída de martensita nova. A ZTA iv (de austenitização intercrítica) de chapas recozidas era formada por uma mistura de martensita nova e martensita revenida. A ZTA iv de chapas temperadas e revenidas apresentou uma mistura de martensita nova, martensita revenida e austenita revertida / Abstract: In this research, metallurgical changes due to heat treatments and friction stir welding of a high alloyed supermartensitic stainless steel SMSS 12Cr/6Ni/2Mo/0, 1Ti were studied. SMSS plates were received after hot rolling and annealing. Mechanical properties and microstructure were out of the technical requirements established for materials quality control used in the oil and gas transportation. An experimental methodology was used to evaluate two different areas: 1) The use of heat treatments to replicate the microstructural conditions used in field applications. 2) Development of friction stir processing and welding parameters. The microstructural conditioning was conducted by using different intercritical tempering temperatures: 610, 625, 650, 670, 700 and 720 °C during 9000 seconds. To study the kinetics of phase transformation during heating, soaking and cooling, it was used a thermomechanical simulator Gleeble3S50¿, coupled to a source of synchrotron radiation, at XTMS facility belonging to the Brazilian Synchrotron Light Laboratory. The development of friction stir processing and welding parameters was conducted in dedicated equipment for FSW at the National Laboratory for Nanotechnology. A composite W-Re (matrix)/PCBN reinforced tool with 9.2 to 9.5 mm long threaded conical pin and convex threaded shoulder was used. Spindle speeds between 400 RPM and 200 RPM, and welding speeds between 100 and 75 mm.min-1, were evaluated. It was possible to replicate the hardness and phase fractions of a commercial SMSS pipe by using an intercritical tempering. The best temperature was 610 °C, since it can generate a tempered martensite matrix with 15% of reverted austenite and 2% of fresh martensite after cooling at room temperature. It was also possible to obtain a sound defect-free processing using 250 rpm and 100 mm.min-1. To perform a two passes welding joint of 17.9 mm thickness, the best combination of parameters to obtain good surface quality and minimal amount of internal defects was 300 RPM and 100 mm.min-1. For the two microstructural conditions evaluated (hot rolled and annealed; and quenched and tempered), the nugget zone consisted of blocks of fresh martensite with progressive grain refinement toward the root of the welded passes. Three heat affected zones HAZ, were identified, regarding the five reported by arc welding. The HAZ i and ii (high temperature) were not found, completely suppressing the delta ferrite precipitation. The HAZ iii (fully austenitized) consisted of fresh martensite. The HAZ iv (partially austenitized) of hot-rolled and annealed plates consisted of a mixture of fresh martensite and tempered martensite. The HAZ iv of quenched and tempered plates consisted of a mixture of fresh martensite, tempered martensite and reverted austenite / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

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