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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.
11

Mineral composition of hypothermally induced ankylosis in rat molars.

Leung, Albert January 2010 (has links)
This study used Backscattered electron imaging (BSE) and X-ray Microanalysis to qualitatively and quantitatively investigate morphology and elemental composition of ankylotic adaptation in the periodontium following hypothermic insult to their maxillary first molars. This method has been shown in previous studies to induce aseptic root resorption along with ankylotic changes within the periodontal ligament (PDL). A secondary objective was to assess the pulpal changes that occurred concurrent with the changes in the periodontium. Twenty-eight eight week old Sprague Dawley rats were divided into four groups of seven animals corresponding to one of four observation periods i.e.: t₁= 7 days, t₂= 14 days, t₃= 21 days, t₄ = 28 days. At t=0 days, six animals in each group received a thermal insult as a continuous 20 minute application of dry ice (CO₂ at -81⁰C) to the crowns of their upper right maxillary molar. The untreated left molars were used as controls. The remaining rat within each group did not receive the dry ice. All rats were given two sequential bone labels, calcein 5mg/kg and alizarin red 30mg/kg, administered intraperitoneally 8 days apart. The timing of the labels was such that all rats were euthanased 2 days after the last label. Following sacrifice, the maxillae were dissected out, fixed in ethanol and embedded in methylmethacrylate. Ten microns thick, undecalcified maxillary first molar coronal sections through the furcation were obtained. For every 3 out of 10 sections: the first was left unstained and undecalcified; the second stained with Von Kossa/haematoxylin & eosin; and the third decalcified and stained with haematoxylin & eosin. Unstained sections were viewed under fluorescence, while transmitted light microscopy was used for the other sections. Following initial analysis, the unstained, undecalcified sections were de-coverslipped and carbon coated. These sections were investigated with scanning electron microscopy and Energy Dispersive X-ray Spectrometry (EDS). Quantitative spot analysis and element mapping was performed on alveolar bone, ankylotic areas, cementum and dentine. A linear mixed effects model was employed to investigate any interaction between the four tissues of interest. A focal pattern of ankylosis was observed at days 14 and 21 in three rats. No ankylosis was observed in the control teeth. SEM revealed a focal type of ankylosis with central nodules of mineralized tissue forming within the PDL. Bridging between bone and dentine occurred with fine trabeculae which extended from the central mineralized nodule. Bridging was progressive and was more extensive at day 21 compared to day 14. At day 28, no ankylosis was observed. EDS analysis revealed that the ankylotic tissue was composed of major constituents Calcium and Phosphorous along with trace elements of Mg and Na. This was comparable to the surrounding alveolar bone, cementum and dentine. There was no statistically significant difference in the Ca/P ratios, Mg when ankylotic material was compared to bone. There was a trend towards elevated Na levels in ankylosis but this was not statistically significant relative to bone. Mg in dentine was lower than for all the other tissues and Na was higher in dentine when compared to bone and cementum. In the pulp, hypothermic injury demonstrated alteration of the odontoblast layer, reduction in cellularity, vascular alterations and tertiary dentin formation. At the 28 day observation period, the cellular and vascular changes had returned to levels comparable to the control teeth, indicating successful pulpal healing and regeneration. Marked tertiary dentine deposition was also observed at days 14, 21 and 28. Pulp chambers were visibly smaller due to tertiary dentine formation, however no pulp necrosis was observed. Thus the aseptic root resorption model, using a continuous 20 minute application of dry ice, suggested the occurrence of reversible pulpal tissue alterations compatible with an inflammatory repair process. The observation of ankylosis initiating as centralised nodules within the PDL suggest that the origins may be a consequence of osteogenic potential from PDL stem cells. The null hypothesis that a single, prolonged thermal insult on a rat molar does not have an effect on mineralized tissue formation and that ankylotic tissue is similar to bone was rejected. ABSTRACT There is a presumption that the ankylotic region formed after periodontal ligament (PDL) injury represents an unremarkable bony repair process. Essentially, the injury triggers an osteogenic repair response and the ankylotic tissue merely represents alveolar bone. There is uncertainty whether the oestogenic event is predominantly osteoblast driven, cementoblast directed, or a consequence of osteogenic potential from PDL stem cells. In this study, twenty-eight Sprague Dawley rats were divided into four groups of six animals, corresponding to one of four observation periods, and received a thermal insult as a continuous 20 minute application of dry ice to the crowns of their upper right maxillary molar. The appearance of ankylotic tissues was examined using backscattered electron images using a scanning electron microscope (SEM) equipped with an Energy Dispersive X-ray Analyser (EDS). The Ca, P, and trace elements contents were determined by EDS from four different hard tissue regions: ankylosis; bone; dentine and cementum, and the Ca/P ratios were calculated. Ankylosis was observed at days 14 and 21 in 3 rats and was not seen at day 28. No ankylosis was observed in the control teeth. BSE imaging revealed a focal type of ankylosis with central nodules of mineralized tissue forming within the PDL. The morphological features of ankylotic tissue differed to that of alveolar bone and dentine. Bridging between bone and dentine occurred with fine trabeculae which extended from the central mineralized nodule. EDS analysis showed that the ankylotic tissue was composed of major constituents Ca and P along with trace elements of Mg and Na. This was comparable to the surrounding alveolar bone, cementum and dentine. There was no statistically significant difference in the Ca/P ratios, Mg, and Na between ankylotic material and bone. Statistically significant differences was evident in Mg content between ankylotic material compared to dentine and cementum. Na content was higher in dentine than in ankylotic material. The results of this study indicate that, histochemically, ankylotic material is similar to bone. However, the appearance of ankylotic material as centralised foci with a morphology different from bone suggest that ankylosis may originate from an osteoblastic phenotype originating within PDL. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1522156 / Thesis (D.Clin.Dent.) -- University of Adelaide, School of Denstistry, 2010
12

Mineral composition of hypothermally induced ankylosis in rat molars.

Leung, Albert January 2010 (has links)
This study used Backscattered electron imaging (BSE) and X-ray Microanalysis to qualitatively and quantitatively investigate morphology and elemental composition of ankylotic adaptation in the periodontium following hypothermic insult to their maxillary first molars. This method has been shown in previous studies to induce aseptic root resorption along with ankylotic changes within the periodontal ligament (PDL). A secondary objective was to assess the pulpal changes that occurred concurrent with the changes in the periodontium. Twenty-eight eight week old Sprague Dawley rats were divided into four groups of seven animals corresponding to one of four observation periods i.e.: t₁= 7 days, t₂= 14 days, t₃= 21 days, t₄ = 28 days. At t=0 days, six animals in each group received a thermal insult as a continuous 20 minute application of dry ice (CO₂ at -81⁰C) to the crowns of their upper right maxillary molar. The untreated left molars were used as controls. The remaining rat within each group did not receive the dry ice. All rats were given two sequential bone labels, calcein 5mg/kg and alizarin red 30mg/kg, administered intraperitoneally 8 days apart. The timing of the labels was such that all rats were euthanased 2 days after the last label. Following sacrifice, the maxillae were dissected out, fixed in ethanol and embedded in methylmethacrylate. Ten microns thick, undecalcified maxillary first molar coronal sections through the furcation were obtained. For every 3 out of 10 sections: the first was left unstained and undecalcified; the second stained with Von Kossa/haematoxylin & eosin; and the third decalcified and stained with haematoxylin & eosin. Unstained sections were viewed under fluorescence, while transmitted light microscopy was used for the other sections. Following initial analysis, the unstained, undecalcified sections were de-coverslipped and carbon coated. These sections were investigated with scanning electron microscopy and Energy Dispersive X-ray Spectrometry (EDS). Quantitative spot analysis and element mapping was performed on alveolar bone, ankylotic areas, cementum and dentine. A linear mixed effects model was employed to investigate any interaction between the four tissues of interest. A focal pattern of ankylosis was observed at days 14 and 21 in three rats. No ankylosis was observed in the control teeth. SEM revealed a focal type of ankylosis with central nodules of mineralized tissue forming within the PDL. Bridging between bone and dentine occurred with fine trabeculae which extended from the central mineralized nodule. Bridging was progressive and was more extensive at day 21 compared to day 14. At day 28, no ankylosis was observed. EDS analysis revealed that the ankylotic tissue was composed of major constituents Calcium and Phosphorous along with trace elements of Mg and Na. This was comparable to the surrounding alveolar bone, cementum and dentine. There was no statistically significant difference in the Ca/P ratios, Mg when ankylotic material was compared to bone. There was a trend towards elevated Na levels in ankylosis but this was not statistically significant relative to bone. Mg in dentine was lower than for all the other tissues and Na was higher in dentine when compared to bone and cementum. In the pulp, hypothermic injury demonstrated alteration of the odontoblast layer, reduction in cellularity, vascular alterations and tertiary dentin formation. At the 28 day observation period, the cellular and vascular changes had returned to levels comparable to the control teeth, indicating successful pulpal healing and regeneration. Marked tertiary dentine deposition was also observed at days 14, 21 and 28. Pulp chambers were visibly smaller due to tertiary dentine formation, however no pulp necrosis was observed. Thus the aseptic root resorption model, using a continuous 20 minute application of dry ice, suggested the occurrence of reversible pulpal tissue alterations compatible with an inflammatory repair process. The observation of ankylosis initiating as centralised nodules within the PDL suggest that the origins may be a consequence of osteogenic potential from PDL stem cells. The null hypothesis that a single, prolonged thermal insult on a rat molar does not have an effect on mineralized tissue formation and that ankylotic tissue is similar to bone was rejected. ABSTRACT There is a presumption that the ankylotic region formed after periodontal ligament (PDL) injury represents an unremarkable bony repair process. Essentially, the injury triggers an osteogenic repair response and the ankylotic tissue merely represents alveolar bone. There is uncertainty whether the oestogenic event is predominantly osteoblast driven, cementoblast directed, or a consequence of osteogenic potential from PDL stem cells. In this study, twenty-eight Sprague Dawley rats were divided into four groups of six animals, corresponding to one of four observation periods, and received a thermal insult as a continuous 20 minute application of dry ice to the crowns of their upper right maxillary molar. The appearance of ankylotic tissues was examined using backscattered electron images using a scanning electron microscope (SEM) equipped with an Energy Dispersive X-ray Analyser (EDS). The Ca, P, and trace elements contents were determined by EDS from four different hard tissue regions: ankylosis; bone; dentine and cementum, and the Ca/P ratios were calculated. Ankylosis was observed at days 14 and 21 in 3 rats and was not seen at day 28. No ankylosis was observed in the control teeth. BSE imaging revealed a focal type of ankylosis with central nodules of mineralized tissue forming within the PDL. The morphological features of ankylotic tissue differed to that of alveolar bone and dentine. Bridging between bone and dentine occurred with fine trabeculae which extended from the central mineralized nodule. EDS analysis showed that the ankylotic tissue was composed of major constituents Ca and P along with trace elements of Mg and Na. This was comparable to the surrounding alveolar bone, cementum and dentine. There was no statistically significant difference in the Ca/P ratios, Mg, and Na between ankylotic material and bone. Statistically significant differences was evident in Mg content between ankylotic material compared to dentine and cementum. Na content was higher in dentine than in ankylotic material. The results of this study indicate that, histochemically, ankylotic material is similar to bone. However, the appearance of ankylotic material as centralised foci with a morphology different from bone suggest that ankylosis may originate from an osteoblastic phenotype originating within PDL. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1522156 / Thesis (D.Clin.Dent.) -- University of Adelaide, School of Denstistry, 2010
13

DESENVOLVIMENTO DE TÉCNICA PARA DETECÇÃO DE POLUENTES EM ESTUÁRIOS UTILIZANDO MICROSCOPIA ANALÍTICA EM TESTAS DE FORAMINÍFEROS

Campos, Maili Correia 02 1900 (has links)
Submitted by Everaldo Pereira (pereira.evera@gmail.com) on 2018-05-27T13:19:44Z No. of bitstreams: 1 Tese_ Maili.pdf: 3406508 bytes, checksum: 68e4dbf31e83e41fe741e4bddc896e5f (MD5) / Made available in DSpace on 2018-05-27T13:19:44Z (GMT). No. of bitstreams: 1 Tese_ Maili.pdf: 3406508 bytes, checksum: 68e4dbf31e83e41fe741e4bddc896e5f (MD5) / Os estuários são ambientes transicionais bastante produtivos biologicamente que apresentam uma grande complexidade devido à interação de diversos fatores físicoquímicos. Tais ambientes têm sido alvo de intensa exploração humana e isto pode ocasionar o comprometimento do equilíbrio do ecossistema dessas regiões costeiras tornando os programas de diagnóstico, de monitoramento e de manejo cada vez mais necessários. A análise do sedimento é a mais indicada neste tipo de investigação porque permite determinar padrões de dispersão e localizar depósitos de contaminantes, como os metais-traço, que possam escapar à detecção pela análise da água. Associado a isso, a assembleia de foraminíferos tem sido amplamente utilizada como bioindicadora de poluição, já que tais são organismos sensíveis às mudanças ambientais e produzem uma testa capaz de expressar as mudanças no ambiente. A microscopia analítica é um método confiável para a detecção e mensuração da concentração de elementos químicos nas testas destes organismos. Este estudo objetivou dete rminar a ocorrência de biodisponibilização de metais no sedimento do estuário do rio Jacuípe e Paraguaçu, utilizando a distribuição espacial das assembleias e a microanálise nas testas de foraminíferos. Foram coletadas 32 amostras do sedimento no estuário do rio Jacuípe (Litoral Norte da Bahia) nos meses de janeiro e junho de 2010 e 18 no estuário do rio Paraguaçu (BTS) em 2011, em pontos distribuídos ao longo do canal com auxílio de um Van Veen. Amostras de sedimento foram encaminhadas para o LEPETRO (IGEO/UFBA) para a análise geoquímica e determinação do teor de matéria orgânica. Testas normais, da espécie principal encontrada nos dois estuários, foram triadas e fixadas em stubs cobertos de ouro as quais foram levadas ao MEV/EDS de modelo JSM 6610LV (JEOL) do LAMUME (IF/UFBA).A utilização do stub de ouro em substituição ao de alumínio no MEV/EDS apresentou-se como um método eficiente para a produção de imagem e espectros químicos com baixo teor de ruído. O éster de cianoacrilato como fixador dos foraminíferos nos stubs de ouro mostrou-se pouco eficiente. A goma adraganta foi um bom fixador para amostras de natureza carbonática. Em ambas as estações nos dois estuários encontrou-se uma baixa diversidade na assembleia de foraminíferos e espécies do gênero Ammonia estavam entre as principais. A análise geoquímica do sedimento revelou que nos dois estuários estudados, o teor de metais máximos não ultrapassou os valores de referência da resolução 454/12 do CONAMA. Os teores de matéria orgânica foram baixos nos dois estuários em ambas as estações. Em todas as testas dos foraminíferos estudadas, os elementos químicos encontrados em maior concentração foram: carbono e oxigênio. Não foi detectada a presença de metaistraço em nenhum exemplar nos dois estuários. / ABSTRACT The estuaries are biologically productive transitional environments that present great complexity due to the interaction of several physicochemical factors. Such environments have been the target of intense human exploration and this can cause the compromise of the ecosystem equilibrium of these coastal regions making diagnostic, monitoring and management programs increasingly necessary. The analysis of the sediment is the most indicated in this type of investigation because it allows to determine dispersion patterns and to locate deposits of contaminants, like trace metals, that can escape to the detection by the analysis of the water. Associated with this, the foraminifera assembly has been widely used as a bioindicator of pollution, as these are organisms sensitive to environmental changes and produce a forehead capable of expressing changes in the environment. Analytical microscopy is a reliable method for the detection and measurement of the concentration of chemical elements in the testis of these organisms. This study aimed to determine the occurrence of bioavailability of metals in the sediments of the Jacuípe and Paraguaçu river estuaries, using spatial distribution of assemblages and microanalysis in the foraminifera Thirty-two sediment samples were collected in the estuary of the Jacuípe River (North Coast of Bahia) in January and June 2010 and 18 in the estuary of the Paraguaçu River (BTS) in 2011, in points distributed along the channel with the aid of a Van Veen. Sediment samples were sent to LEPETRO (IGEO / UFBA) for geochemical analysis and determination of organic matter content. Normal samples of the main species found in the two estuaries were screened and fixed in gold - covered stubs which were taken to SEM / EDS model JSM 6610LV (JEOL) from LAMUME (IF / UFBA).The use of the gold stub instead of the aluminum stub in the SEM / EDS was presented as an efficient method for the production of image and chemical spectra with low noise. The cyanoacrylate ester as a fixer of the foraminifera in the gold stubs proved to be inefficient. Adraganta gum proved to be a good fixative for carbonate samples. In both seasons, in the two estuaries, was found a low diversity in the assembly of foraminifera and species of the genus Ammonia were among the main. The geochemical analysis of sediment revealed that in the two studied estuaries, the maximum metals content did not exceed the reference values of resolution 454/12 of CONAMA. The organic matter contents were low in both estuaries in both seasons. In all the brows of the studied foraminifera, the chemical elements found in the highest concentrations were: carbon and oxygen. The presence of trace metals was not detected in any specimen in the two estuaries.
14

Vikingatida förgyllningstekniker : En studie av förgyllningstekniker tillämpade på föremål från Birka med SEM-EDS

Patriksdotter, Amanda January 2019 (has links)
Studies with primary focus on Viking age gilding techniques in Scandinavia has not been carried out since the sixties. During the past 50 years knowledge about prehistoric gilding techniques and traces of them in the archeological material, as well as the usage of natural sciences within archaeology, has developed considerably. The aim of this thesis was to revisit the topic of gilding and shed new light on Viking age metalworking in Scandinavia with focus on gilding techniques. The second aim was to determine the possibilities and limitations of the study of gilding with a non-destructive methodology. The surfaces of 13 metal objects, four of which are indigenous and the rest are imported goods, were analyzed with SEM-EDS. The chemical compositions of the gilded layers as well as the underlying silver- or copper alloys were analyzed. Furthermore, observations of micro morphological structures were carried out on the gilt surfaces. Interpretations of both chemical compositions and micro morphology were carried out in order to identify what technique or techniques have been used for gilding. The results show that two of artefacts have not been gilded at all, five of them have been fire gilded and the results of the remaining six objects are inconclusive mainly due to lacking reference data. It can be concluded that further research regarding the aging of gilt surfaces on gilded artefacts, more specifically the loss of mercury in fire gilded surfaces over time, needs to be carried out.
15

Avaliação de procedimentos de preparação de amostras e rotinas de análises de imagem automatizada por microscopia eletrônica de varredura. / Samples preparation procedures and automated image analysis routines evaluation by scanning electron microscopy.

Carmo, Sheila Schuindt do 27 February 2015 (has links)
A análise de imagens automatizada tem atualmente importante papel no setor mineral, devido à rapidez das análises e à confiabilidade dos resultados. A técnica pode ser realizada por meio de imagens adquiridas em microscópio eletrônico de varredura, geralmente associada a microanálises químicas por EDS. Estas analises podem ser realizadas em diversas etapas de um empreendimento mineiro: no auxílio à exploração, lavra (blendagens), processos de beneficiamento (associação mineral), estudos de gênese e controles de mineralização. Essa técnica permite a análise estatística de grande número de partículas/dados, fornecendo informações de composição mineralógica, química mineral, partição de elementos, associações minerais incluindo liberação de fases de interesse, entre outros. Este estudo investiga a aplicabilidade da análise de imagens automatizada em amostras de minério de ferro, com base em diferentes procedimentos de preparação de amostras e rotinas de análise avaliadas por meio do sistema MLA. Um minério de ferro foi escolhido por se tratar de um minério já bastante estudado e bem documentado na bibliografia e que mostra, em geral, mineralogia e texturas simples e repetitivas facilitando a análise dos resultados obtidos com os diferentes procedimentos e rotinas aplicadas. Além disso, o minério de ferro apresenta fases minerais com significativas diferenças de peso específico, o que pode acarretar em maiores dificuldades em termos de amostragem e preparação de amostras. / The automated image analysis has an important role in the mineral industry due to the quickly analysis and the results reliability. The technique can be applied using images from a scanning electron microscope associated usually coupled with chemical microanalysis from an EDS system. These analyses are carried out in many stages of a mining project helping mineral exploration, mining (blending), mineral processing (mineral association), genetic studies and mineralization control. This technique allows a statistic analysis of a large numbers particles and data, providing information of mineralogical composition, mineral chemistry, elemental distribution, mineral associations, phase and spectra liberation and others. This study sets the applicability of automated image analysis of an iron ore sample with diverse preparation procedures and analysis routines, which were evaluated by the MLA system. An iron ore sample was chosen because it is a familiar and well-documented ore in the literature, that usually shows simple textures and mineralogy which makes easier the interpretation of results by a diversity of preparation procedures and analysis routines. Furthermore, the iron ore shows mineral phases with significant differences in specific gravity resulting in more difficulties in sampling and preparation procedures due to potential density segregation.
16

Avaliação de procedimentos de preparação de amostras e rotinas de análises de imagem automatizada por microscopia eletrônica de varredura. / Samples preparation procedures and automated image analysis routines evaluation by scanning electron microscopy.

Sheila Schuindt do Carmo 27 February 2015 (has links)
A análise de imagens automatizada tem atualmente importante papel no setor mineral, devido à rapidez das análises e à confiabilidade dos resultados. A técnica pode ser realizada por meio de imagens adquiridas em microscópio eletrônico de varredura, geralmente associada a microanálises químicas por EDS. Estas analises podem ser realizadas em diversas etapas de um empreendimento mineiro: no auxílio à exploração, lavra (blendagens), processos de beneficiamento (associação mineral), estudos de gênese e controles de mineralização. Essa técnica permite a análise estatística de grande número de partículas/dados, fornecendo informações de composição mineralógica, química mineral, partição de elementos, associações minerais incluindo liberação de fases de interesse, entre outros. Este estudo investiga a aplicabilidade da análise de imagens automatizada em amostras de minério de ferro, com base em diferentes procedimentos de preparação de amostras e rotinas de análise avaliadas por meio do sistema MLA. Um minério de ferro foi escolhido por se tratar de um minério já bastante estudado e bem documentado na bibliografia e que mostra, em geral, mineralogia e texturas simples e repetitivas facilitando a análise dos resultados obtidos com os diferentes procedimentos e rotinas aplicadas. Além disso, o minério de ferro apresenta fases minerais com significativas diferenças de peso específico, o que pode acarretar em maiores dificuldades em termos de amostragem e preparação de amostras. / The automated image analysis has an important role in the mineral industry due to the quickly analysis and the results reliability. The technique can be applied using images from a scanning electron microscope associated usually coupled with chemical microanalysis from an EDS system. These analyses are carried out in many stages of a mining project helping mineral exploration, mining (blending), mineral processing (mineral association), genetic studies and mineralization control. This technique allows a statistic analysis of a large numbers particles and data, providing information of mineralogical composition, mineral chemistry, elemental distribution, mineral associations, phase and spectra liberation and others. This study sets the applicability of automated image analysis of an iron ore sample with diverse preparation procedures and analysis routines, which were evaluated by the MLA system. An iron ore sample was chosen because it is a familiar and well-documented ore in the literature, that usually shows simple textures and mineralogy which makes easier the interpretation of results by a diversity of preparation procedures and analysis routines. Furthermore, the iron ore shows mineral phases with significant differences in specific gravity resulting in more difficulties in sampling and preparation procedures due to potential density segregation.
17

Utilização da técnica de fluorescência de raios X por dispersão em energia (EDXRF) na avaliação do material particulado em suspensão na cidade de Limeira - SP / Using energy dispersive X ray fluorescence (EDXRF) technique to evaluate the suspended particulate matter from Limeira city, State of São Paulo, Brazil

Moraes, Liz Mary Bueno de 31 August 2009 (has links)
O objetivo principal deste trabalho foi avaliar a composição química do material particulado em suspensão na atmosfera na cidade de Limeira/SP, pela técnica de fluorescência de raios X dispersiva em energia (EDXRF). Um amostrador tipo stacker foi utilizado para coletar particulados fino (partículas com diâmetro aerodinâmico entre 2,5 e 10 \'mü\'m) e grosso (partículas maiores que 10 \'mü\'m), utilizando filtros de policarbmüonato de 47 mm de diâmetro e com diâmetros de poro de 0,4 e 8 \'mü\'m, respectivamente. As amostras foram coletadas em 2006 (de janeiro a dezembro), 2008 (de janeiro a abril e de julho a dezembro) e 2009 (de janeiro a março). Na excitação da técnica de EDXRF utilizou-se um tubo de Mo com filtro de Fe (análise sob vácuo) para a determinação dos elementos do Al ao Ca, e com filtro de Zr (análise sob ar atmosférico) para determinação do Sc ao Zn e também do Pb. Para a detecção dos raios X utilizou-se um detector semicondutor de Si(Li) acoplado a um analisador multicanal, com um tempo de aquisição de 300 s. Os espectros de raios X foram interpretados através do programa AXIL e a para a quantificação dos elementos químicos fez-se o uso da metodologia dos parâmetros fundamentais. Realizou-se também microanálises nas amostras utilizando-se um microscópio eletrônico de varredura acoplado a um sistema de fluorescência de raios X por dispersão em energia (SEM/EDS) para a caracterização química e morfológica das partículas coletadas no material particulado em suspensão. Determinou-se também a concentração de negro de fumo (black carbon) utilizando a técnica de reflectância. Embora a amostragem não tenha sido suficiente para indicar a contribuição de cada fonte de emissão, a metodologia de análise de agrupamento possibilitou a identificar duas principais fontes para o material particulado em suspensão: poeira de solo e resíduos de queima de cana-de-açúcar / The main objective of this work was to evaluate the chemical composition of the suspended particulate matter from the atmosphere of the city of Limeira, State of São Paulo, by energy dispersive X-ray fluorescence (EDXRF) technique. A stacker filter sampler was used to collect the fine (particles with aerodynamic diameter between 2.5 and 10 \'mü\'m) and the gross particulates (particles larger than 10 \'mü\'m) employing 47 mm polycarbonate filters, with 0.4 and 8 \'mü\'m pore diameters, respectively. Samples were collected in 2006 (from January to December), 2008 (from January to April and from July to December), and 2009 (from January to March). The EDXRF excitation was carried out using a Mo X-ray tube with Fe filter (analysis under vacuum) to determine elements from Al to Ca, and with Zr filter (analysis under air atmosphere) to determine from Sc to Zn and also Pb. A Si(Li) semiconductor detector coupled to a multichannel analyzer was used for X-ray detection, with 300 s acquisition time. The X-ray spectra were deconvoluted by the AXIL software, and fundamental parameters methodology was adopted for quantification. Samples microanalysis by scanning electron microscope, connected to an energy dispersive X-ray fluorescence system (SEM/EDS) was carried out for chemical and morphological characterization of collected particles in the suspended particulate matter. Black carbon content was also evaluated by reflectance. Despite the fact that the sampling was not enough to indicate the contribution of each emission source, grouping analysis statistical method allowed to identify two main sources of the particulate matter in suspension: dust soil and sugar cane burning residues
18

Efeito de três diferentes doses de radiação com raios-X na microdureza, morfologia superficial, espectrometria de energia dispersiva de radios-X (EDS) e resistência de união ao esmalte e dentina com dois diferentes sistemas adesivos / The effect of three different doses of radiation with x-rays in the microhardness, superficial morfology, energy dispersive X-ray spectroscopy (EDS) and bond strength of enamel and dentin with two adhesive systems

Cunha, Sandra Ribeiro de Barros da 19 January 2015 (has links)
Este estudo teve como objetivo analisar dentina e esmalte irradiados com diferentes doses de radiação ionizante com raios-x (20, 40 e 70Gy), através da microdureza, morfologia superficial, conteúdo mineral e resistência de união com adesivo de condicionamento total de 2 etapas (Adper Single Bond 2) e um novo sistema adesivo, universal, com a técnica auto-condicionante (Universal Single Bond). Oitenta e quatro terceiros molares humanos foram cortados, separados e preparados para cada ensaio. Para os ensaios de microdureza e microcisalhamento as amostras foram incluídas em resina acrílica e polidas. Para a microscopia eletrônica de varredura (MEV) e espectrometria de energia dispersiva de raios-x (EDS), as amostras foram fixadas em solução de glutaraldeído 3%, lavadas em solução de cacodilato 0,1M e desidratadas em álcool etílico crescente. A microdureza (n=30) foi realizada pré e pós-radioterapia, com força de 50gf em esmalte cervical, médio e oclusal e 25gf em dentina profunda, média e rasa, por 30s. As amostras para o microcisalhamento foram divididas em 4 grupos (n=20) e 2 subgrupos (n=10) conforme o sistema adesivo. Foram construídos 3 corpos de prova cilíndricos com 1mm de diâmetro e altura em cada amostra. O teste de microcisalhamento foi realizado em máquina de ensaio universal com velocidade de 1mm/min. Os resultados indicam perda de propriedade de microdureza apenas em esmalte cervical em todas as três doses (20Gy pré-radioterapia: 298,04±11,80 e pós-radioterapia: 294,36±16,68; 40Gy pré-radioterapia: 285±19,45 e pósradioterapia: 275,3±36; 70Gy pré-radioterapia: 291,98±16,51 e pós-radioterapia: 283,68 ± 21,64) e em dentina em todas as profundidades (profunda: 20Gy préradioterapia: 57,79±1,96; pós-radioterapia: 55,37±1,30; 40Gy pré-radioterapia: 57,31±1,76; pós-radioterapia: 55,83±1,63; 70Gy não apresentou alterações; média: 20Gy pré-radioterapia: 58,05±1,79; pós-radioterapia: 55,36±1,20; 40Gy préradioterapia: 57,87± 2,04; pós-radioterapia: 55,65 ± 2,48; 70Gy não apresentou alterações; rasa: 20Gy pré-radioterapia: 56,60±12,17; pós-radioterapia: 55,18±2,57; 40Gy pré-radioterapia: 57,36±2,78; pós-radioterapia: 55,18± 2,57; 70Gy préradioterapia: 55,08±1,94; pós-radioterapia: 54,72±2,57). O teste de microcisalhamento não apresentou diferença significativa entre grupo controle e as 3 doses, tanto para esmalte (p=0,325) como para dentina (p=0,719), apresentando o adesivo Universal Single Bond, em dentina, a resistência de união mais satisfatória. A análise de padrão de fratura para dentina, indicou um maior número de rupturas coesivas em dentina na dose 70Gy quando comparada ao grupo controle. Em esmalte prevaleceram as fraturas do tipo adesivas. As eletromicrografias apresentaram alterações apenas em esmalte na dose 70Gy, com prismas de esmalte mais curtos e arredondados. O EDS mostrou que o conteúdo mineral permaneceu intacto em ambos substratos. Dentro das limitações de um estudo in vitro, conclui-se que a radiação ionizante apresenta maior interação preferencialmente em dentina, no entanto, o EDS mostra não haver modificação no conteúdo mineral em ambos substratos. Existe uma diminuição da microdureza em dentina, porém as alterações não são suficientes para interferir na resistência de união dos substratos irradiados, que mostraram resultados mais satisfatórios com o sistemas adesivos universal, utilizando-se a técnica auto-condicionante. / The aim of this study was to evaluate the effects of different doses (20Gy, 40Gy and 70Gy) of ionizing radiation with x-rays in the microhardness, superficial morphology, mineral content and bonding effectiveness with a 2 steps all-etch adhesive (Adper Single Bond 2) and the new generation of adhesive, the universal adhesive system, (Universal Single Bond), using the self-etch technique. Eighty-four third molars were cutted, separed and prepared for each assay. For the microshear-bond and microhardness the samples were included in acrylic resin and then polished. For the scanning electron miscroscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), the samples were fixated in a 3% glutaraldehyde solution, washed in 0,1M cacodylate solution and dehydrated in increscent concentrations of ethyl alcohol. The microhardness (n=30) was held pre and post radiotherapy with 50gf on cervical, middle and occlusal enamel and 25kg on superficial, middle and deep dentin, both cases with 30s. The microshear-bond was divided in 4 groups (n=20) and 2 subgroups (n=10) according to the adhesive system. Three cylinders were built with 1mm in diameter and heigh in every sample. The assay were accomplished at an universal testing machine with 1mm/min. Results indicate loss of microhardness properties only in cervical enamel at all 3 doses (20Gy pre-radiotheraphy: 298,04 ± 11,80 and post-radiotherapy: 294,36 ± 16,68; 40Gy pre-radiotherapy: 285 ± 19,45 and post-radiotherapy: 275,3 ± 36; 70Gy pre-radiotherapy: 291,98 ± 16,51 and post-radiotherapy: 283,68 ± 21,64) and in all dentin depths (deep: 20Gy preradiotherapy: 57,79 ± 1,96; post-radiotherapy: 55,37 ± 1,30; 40Gy pre-radiotherapy: 57,31 ± 1,76; post-radiotherapy: 55,83 ± 1,63; 70Gy showed no alteration; Middle: 20Gy pre-radiotherapy: 58,05 ± 1,79; post-radiotherapy: 55,36 ± 1,20; 40Gy preradiotherapy: 57,87 ± 2,04; post-radiothetrapy: 55,65 ± 2,48; 70Gy showed no alteration; Superficial: 20Gy pre-radioterapia: 56,60 ± 12,17; post-radiotrapia: 55,18 ± 2,57; 40Gy pre-radiotherapy: 57,36 ± 2,78; post-radiotherapy: 55,18 ± 2,57; 70Gy pre-radiotherapy: 55,08 ± 1,94; post-radiotherapy: 54,72 ± 2,57). The microshearbond test did not show significant difference between the control group and the 3 doses, both enamel (p=0.325) and dentin (p=0.719), showing better bonding with Universal Single Bond adhesive in dentin. The fracture pattern analysis indicated a larger number of cohesive failure in dentine with the 70Gy dose when compared with control group. The micrographs showed changes only on enamel at 70Gy dose, with shorter and rounder prisms. EDS test indicated no changes in mineral content for both substrates. Knowing the limitations of an in vitro study, it were concluded that ionizing radiation shows deleterious effects preferentially in dentin, probably due to it\'s high organic content, since EDS showed no modifications both enamel and dentin. There is a reduction in microhardness on dentin, but the changes are not enough to interfere at bonding properties of irradiated substrates, showing better results when used the universal adhesive with the self-etch techniques.
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Malmmikroskopi, SEM-EDS-  undersökning och framställning  av polerprov från en sektion av  Lovisagruvans sulfidmalm,  Bergslagen / Ore Microscopy, SEM-EDS and Preparation of Polished Samples from a Section of the Lovisagruvan Sulphide Ore, Bergslagen

Ghaderidosst, Joanna January 2019 (has links)
I detta arbete har polerprov framställts för att därefter undersökas med malm- och svepelektronmikroskopi (SEM) med energidispersiv röntgenspektroskopisk analys (EDS). Med dessa metoder har mineralsammansättning, strukturer och texturer identifierats och undersökts. De undersökta proverna kommer från borrkärnor genom malmzonen i Lovisagruvan i Bergslagen, södra Mellansverige. Malmen är en tabulär, silverförande Zn-Pb-sulfidmineralisering.  De kombinerade undersökningarna av polerproven visar att de huvudsakligen består av zinkblände, blyglans, kvarts, mikroklin, granat, amfibol och pyrit, vilka karakteriseras av texturer som visar på omkristallisation, heterogen deformation och lokal remobilisering. De uppvisar småskaliga texturer som sannolikt är direkt relaterade till uppkomsten av s.k. kulmalmstextur. De ingående mineralens inbördes relationer tyder på att blyglans och zinkblände bildades samtidigt och därefter, under regionalmetamorfa förhållanden, tillväxte pyrit och granat som porfyroblaster. Majoriteten av texturerna och strukturerna är sekundära och visar på en kraftig senare överprägling av malmen genom metamorfos och flerfasig deformation under olika tryck- och temperaturförhållanden. / In this project polished sections have been prepared for study by means of ore and scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS). The application of these methods allows mineralogy, structures and textures to be characterized. This was done within the EU H2020-funded project X-Mine. The studied samples are from drill cores transecting the ore zone of the Lovisa mine (Lovisagruvan), which is located in Örebro County in the Bergslagen ore province, south central Sweden. Here, a tabular, stratiform silver-bearing Zn-Pb sulphide ore is mined.  Studies of the polished ore sections show that the samples mainly contain sphalerite, galena, quartz, microcline, garnet, amphibole and pyrite, characterized by textures of recrystallisation, heterogeneous deformation and localized remobilization.  The studied samples from the main ore and exhibit textures directly related to the formation off the so-called ball ore. The textural interrelationships of the major minerals indicate that galena and sphalerite formed penecontemporaneously, and then under regional metamorphic conditions, pyrite and garnet formed as porphyroblasts. The majority of the present textures and structures are secondary, representing different stages of metamorphism and deformation under variable P-T-conditions, post-dating original ore formation. / Real-Time Mineral X-Ray Analysis for Efficient and Sustainable Mining, H2020 X-Mine, Projekt-id: 730270
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Compartimentos da matéria orgânica do solo, agregação, mecanismos de proteção e sequestro de carbono influenciados pela calagem superficial em sistema plantio direto

Briedis, Clever 14 June 2010 (has links)
Made available in DSpace on 2017-07-25T19:29:44Z (GMT). No. of bitstreams: 1 Clever Briedis.pdf: 1258130 bytes, checksum: ffdbaa47bb93b2258b4ff51d6b50f9ad (MD5) Previous issue date: 2010-06-14 / Liming is the most often practice used to neutralize soil acidity, and also promotes chemical changes that can alter the soil organic matter (SOM) pools and the mechanisms of flocculation, formation and stabilization of macro-and microaggregates. The objective of this study was to evaluate carbon sequestration, in the whole and in the aggregates samples, and the changes in the SOM pools affected by liming in a long-term no-tillage. The experiment was conducted in an Oxisol, located in Ponta Grossa, PR. The experimental design was a randomized complete block, arranged as split plot with three replications. The main plot consisted of dolomite lime applied on the soil surface at a 0 or 6 Mg ha-1 in 1993, and 0 or 3 Mg ha-1 in 2000 in plots previously with and without lime, and the treatments was assigned as: 0+0, 6+0, 0+3 and 6+3 Mg ha-1. The subplots were represented by sampling depth and consist of 0-2.5, 2.5-5, 5-10 and 10-20 cm layer. The soil samples were taken in September 2008 and the total organic carbon (TOC) was analyzed in the whole sample, in the aggregates and in the particulate organic carbon (POC) and in the fraction associated with minerals carbon (OCAM). Aggregates of 8-19 mm, in the 0-2.5 cm layer were analyzed by using scan microscope spectrometer X-ray (EDS) for elemental analysis of carbon (C) and calcium (Ca). Liming promoted accumulation of TOC mainly in the layer 0-2.5 cm. The TOC stocks at 0-20 cm were 49.9, 52.9, 52.7 and 57.5 Mg ha-1 for 0+0, 6+0, 0+3, 6 +3 treatments, respectively. Stocks in the SOM fractions were also increased with liming. The increase in POC stock was close relationship (R2 = 0.98, P = 0.011) with the C accumulated input through crop residue, which was higher in plots that were limed. A positive correlation was found between TOC and C extracted in hot water (CHW), total polysaccharides (TP) and labile (LP). Correlations also showed that TOC had a closer relationship with POC than with OCAM, suggesting a greater influence on the labile fraction of TOC increase with liming. In aggregate, the effect of liming in TOC accumulation was mainly in 0-2.5 cm depth. The treatments with liming showed high mean weight diameter (MWD), which provided a large stock of TOC in the 8-19 mm aggregate size. A higest proportion of large aggregates with liming was closely correlated with the TOC content of whole sample. The highest liming dosis resulted in both COP and in OCAM, in the largest class of aggregates. The proportion of POC average of the treatments in relation to OCAM, this class of aggregates, has decreased in depth, and were 18, 13, 10 and 8% at depths of 0-2.5, 2.5-5, 50-10 and 10-20, respectively. Elemental analysis of C and Ca showed a positive correlation of those elements contained in a section of clay from the center of 8-19 mm aggregates. The results suggest that application of lime in soil with clay fraction dominated by kaolinite, brings benefits to structuring and promotes an increase of C in the whole sample and in aggregates. / A calagem é a prática mais utilizada para neutralizar a acidez do solo, porém promove também modificações químicas capazes de alterar os compartimentos da matéria orgânica do solo (MOS) e mecanismos de floculação, formação e estabilização de macro e microagregados. O objetivo desse trabalho foi avaliar o seqüestro de carbono, na amostra integral e nos agregados, e as alterações nos compartimentos da MOS afetados por calagem superficial em sistema plantio direto de longa duração. O experimento foi conduzido em um Latossolo Vermelho textura média, no município de Ponta Grossa, PR. O delineamento experimental foi o de blocos completos ao acaso em parcelas subdivididas, com três repetições. As parcelas consistiram da aplicação de calcário dolomítico na superfície do solo na dose de 0 ou 6 Mg ha-1 em 1993, e dose de 0 ou 3 Mg ha-1 em 2000 nas parcelas previamente com e sem calcário, compondo os tratamentos: 0+0; 6+0; 0+3 e 6+3 Mg ha-1. As subparcelas foram constituídas pelas profundidades de coleta, sendo realizadas em 0-2,5, 2,5-5, 5-10 e 10-20 cm de profundidade. As coletas de solo foram realizadas em setembro de 2008 e analisados os conteúdos de carbono orgânico total (COT) na amostra total, nos agregados e nas frações particulada (COP) e associada aos minerais (COAM) da matéria orgânica do solo (MOS). Agregados de 8-19 mm, da camada 0-2,5 cm, foram analisados através do uso de espectrômetro de dispersão de raios X (EDS) para a análise elementar de carbono (C) e cálcio (Ca). A calagem promoveu acúmulo de COT, principalmente na camada 0-2,5 cm. Os estoques de COT na camada de 0-20 cm foram 49,9, 52,9, 52,7 e 57,5 Mg ha-1 para os tratamentos 0+0, 6+0, 0+3 e 6+3, respectivamente. Os estoques nas frações da MOS também foram aumentados com a calagem. O aumento no estoque de COP foi estreitamente relacionado (R2=0,98; P=0,011) com a adição acumulada de C via resíduo cultural, a qual foi mais elevada nas parcelas que receberam calagem. Houve correlação positiva entre COT e carbono em água quente (CAQ), polissacarídeos totais (PT) e lábeis (PL). Correlações também demonstraram que o COT teve relação mais estreita com o COP do que com COAM, sugerindo maior influência da fração lábil no aumento de COT com a calagem. Nos agregados, a calagem proporcionou acúmulo de COT principalmente na profundidade de 0-2,5 cm. A calagem aumentou o diâmetro médio ponderado (DMP), proporcionando grande estoque de COT na classe de agregado 8-19 mm. A elevada proporção de agregados grandes nos tratamentos com calagem foi estreitamente correlacionado com o conteúdo de COT da amostra integral. A maior dose de calcário proporcionou aumento no estoque de COT tanto em COP quanto em COAM, visto principalmente na maior classe de agregados. A proporção de COP em relação ao COAM, na média dos tratamentos, nessa classe de agregados, diminuiu em profundidade, ficando em torno de 18, 13, 10 e 8 % nas profundidades de 0-2,5, 2,5-5, 5-10 e 10-20, respectivamente. Análise elementar de C e Ca demonstraram correlação positiva dos dois elementos contidos em uma secção da fração argila do centro de agregados de 8-19 mm. A aplicação de calcário, em solo dominado na fração argila por caulinita, traz benefícios à estruturação e promove aumento de C na amostra integral e nos agregados.

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