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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

Construção e avaliação de um instrumento para espectroscopia de emissão em plasma induzido por laser (LIBS) : aplicação em ligas metalicas / Construction and evaluation of a laser induced breakdown spectroscopy instrument: application in alloy samples

Cortez, Juliana, 1984- 27 February 2007 (has links)
Orientador: Celio Pasquini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-08T16:03:21Z (GMT). No. of bitstreams: 1 Cortez_Juliana_M.pdf: 4343113 bytes, checksum: d1746c525a8d51ede4e8432a525eecf2 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho um instrumento LIBS com resolução temporal (TRELIBS) foi construído e seu desempenho foi avaliado para análise qualitativa e quantitativa. Além disso, este trabalho apresenta estudos exploratórios acerca da influência de parâmetros que afetam as análises em LIBS. O instrumento foi montado empregando-se óptica e sistema de detecção de última geração: um detector ICCD, um policromador echelle e um laser Q-switched de Nd:YAG. Três configurações do sistema LIBS foram avaliadas. No último arranjo do sistema, o pulso de laser era refletido por um espelho dicróico à 45º para uma lente de distância focal de 25 cm que focava o pulso de laser na superfície da amostra. A radiação foi coletada por uma lente de curta distância focal e depois enviada para o echelle, por uma fibra óptica, e posteriormente para o ICCD. Na análise qualitativa foram avaliados os espectros de uma placa de cobre e zinco, obtendo-se espectros condizentes com a literatura, de acordo com a resolução do echelle. Na avaliação quantitativa, determinou-se manganês em aços acalmados. O sistema apresentou resposta às diferentes concentrações de manganês em 293,30 nm e curvas analíticas foram obtidas. A energia do pulso de laser mostrou ser um fator determinante no desempenho da análise quantitativa. Outros parâmetros como tempo de integração do sinal, tempo de atraso, ganho do MCP, co-adição de pulsos e distância foco-amostra também mostraram ter influência na análise quantitativa. Imagens de MEV e mapeamentos de EDS das crateras formadas pelo laser foram ferramentas importantes para o entendimento do processo de interação laser-amostra-atmosfera / Abstract: In this work a time resolved LIBS instrument (TRELIBS) was built and its performance evaluated in qualitative and quantitative analysis. Additionally, exploratory studies are presented on the influence of parameters that affect the LIBS analysis. The instrument was built employing optical systems and devices of modern technology: an ICCD device, an echelle polychromator and an Q-switched Nd:YAG laser. Three configurations of LIBS system were evaluated. In the last configuration, the laser pulse was reflected by a dicroic mirror at 45º to a lens of 25 cm focal distance that focused the laser pulse on the sample surface. The plasma emission was collected by a lens of short focal distance and sent to the echelle, through of an optical fiber, and later to the ICCD. In qualitative analysis, spectra of copper and zinc foils were evaluated and the spectral lines were found in agreement with literature, considering the echelle resolution. In quantitative analysis, manganese was determined in killed steel. The system presented signals at 293,30 nm whose intensities changes in function of manganese concentration and analytical curves were obtained. The laser pulse energy showed to be an important factor for the success of quantitative analysis. Others parameters such as width, delay time, MCP gain, accumulated laser pulses and distance sample-focusing lens also showed have influence in quantitative analysis. MEV images and surface scanner by EDS of the craters formed by laser were important tools to understanding laser-sample-atmosphere interaction processes / Mestrado / Quimica Analitica / Mestre em Química
2

Study on the Interaction between Refractory and Liquid Steel Regarding Steel Cleanliness

Deng, Zhiyin January 2016 (has links)
The present thesis focuses on the interaction between refractory and liquid steel. The aim of this work is to understand the interaction behavior between refractory and liquid steel regarding steel cleanliness. The effect of different refractories on different inclusions in Al-killed steel was studied in a furnace. The sintering mechanism of filler sand were also investigated in laboratory. In the industrial trials, the attachments of different oxides on the walls of submerged entry nozzle (SEN) were discussed in the cases of high strength low alloy steel (HSLA) and ultra-low carbon steel (ULC). It is found that the effect of alumina and spinel refractory on all the three types of inclusions is very little, while MgO refractory influences the inclusions depending on the activity of dissolved oxygen in liquid steel. At low oxygen level, alumina inclusions could transform into spinel inclusions with the help of MgO refractory, while the effect on spinel and calcium aluminate inclusions is not evident. On the other hand, when the activity of dissolved oxygen is high enough, the evolution of spinel inclusions from alumina inclusions could not be seen. The reaction between chromite and silica grains leading to liquid formation is the main mechanism for the sintering of filler sand. The factors viz. steel composition, silica size and content, operation temperature and process holding time have a strong influence on the sintering of the filler sand. Smaller size and higher content of silica in sand, steel grades containing higher Mn and Al contents, higher temperature and longer holding time would result in serious sintering. The choice of the sand needs to take those factors into account. The results show that solid alumina particles are always agglomerated on the inner wall of SEN in the case of ULC steel. The top slag with high FeO and MnO contents is considered as the main reason of this kind of attachments. The removal of slag might be a good method to avoid the attachments. In the case of HSLA steel, liquid calcium aluminate inclusions could attach on the inner wall of SEN as well. The smoothness of the inner wall of the SEN holds the key of liquid attachments. In addition, the attachment situation on the outer wall of SEN depends on the operations. The oxygen entrainment through the mold powder would result in the formation of plate-like alumina attachments. The control of reoxidation due to oxygen entrainment would help to avoid this situation. / <p>QC 20160816</p>
3

Mamíferos nativos atropelados em uma área no bioma Pampa: variação sazonal e efeito do tipo hábitat

Koenemann, Joceleia Gilmara 31 August 2009 (has links)
Made available in DSpace on 2015-03-05T16:20:41Z (GMT). No. of bitstreams: 0 Previous issue date: 31 / Bolsa para curso e programa de Pós Graduação / A construção de estradas é um fator de perturbação de alto impacto, removendo a cobertura vegetal original, gerando efeito de borda e alterando a função e a estrutura da paisagem. Este tipo de modificação acarreta em sérios impactos à fauna de vertebrados em processo de deslocamento, que se vêem forçados a superar essas barreiras artificiais, elevando o índice de mortalidade. Nesse contexto, investigamos a fauna de mamíferos atropelados em uma região inserida no Bioma Pampa no oeste do Rio Grande do Sul.
4

Hur påverkar naturvårdsåtgärder mängden av vedlevande insekter : Manuellt dödade träd vs självdöda / How conservation measures affect the standing crop of wood-living insects : Manually killed trees vs. snags

Persson, Andreas January 2012 (has links)
Today’s forest managers implement a large number of methods to increase the amount of dead wood in Swedish forests. They use everything from high cutting of trees to girdling trees and burning forests. However, implementation of these measures without proper knowledge of their consequences is a common problem. This study has been performed to increase knowledge about two of these measures, girdling and high cutting, and how these actions affect the number of wood-living insects living on dead trees. A total of 72 trees were randomly selected in four different locations in the municipality of Säffle. The trees, which were birch and alder, were all dead or dying and selected by three criteria, snags (as the reference tree type), girdling and high cut. A total of 15 trees of each type and measure were chosen. The trees which were either ring debarked or high cut were compared with snags to see if there were any differences in the number of wood-living insects. The collections of insects were made with so-called appropriate window traps. The traps were tied to the trees and left out for one week before emptying. The traps 2 were deployed on two separate occasions during June and July 2011. A total of 876 beetle individuals were captured during the study, including 13 longhorn beetles. There was a significantly smaller amount of families in high cut birch compared to the birch snags for the first period, but none for the second period. There were also a significantly smaller amount of families in the girdled birch than in the snags for the second period. There were no differences between the different types of dead trees when comparing insect species. There were no significant differences between the girdled alder and the alder snags, which indicate that girdling does not have a strong effect, although catches were greater for the girdled alder. High cut alder does not exist and therefore only girdled alder could be compared with the alder snags and no differences in insect catches were found. There were differences in sizes of the trees, with birch snags being larger than high cut and girdled birch and alder snags being smaller than debarked alder. There was also a significant difference in degradation rate of birch, with natural birch snags being less decayed than the high cut and girdled birch. There was no difference in the degree of decay for alder. 69 % of the trapped longhorn beetles were found in birch, 31 % on the alder, but this difference was not significant. The conclusion of the study was that high cutting birch leads to a smaller number of tree-living insects than found on natural snags and that the same applies to girdling. Alder requires further study.
5

Nozzle Blockage In Continuous Casting Of Al-killed Sae 1006 And Sae 1008 Steel Grades In Iskenderun Iron And Steel Works

Sakalli, Erhan 01 April 2004 (has links) (PDF)
In this work, nozzle clogging in the submerged entry nozzle in continuous casting of Al killed steels has been studied. The study has been based on low silicon Al killed SAE 1006 (1.2006) and SAE 1008 (1.2008) grades. In this study, castabilities of 75 heats for 1.2006 steel grades and 75 heats for 1.2008 steel grades have been investigated. Castabilities of the experimental heats have been found to be affected by Al content in oxide form (Aloxy) and Ca content of the liquid steel. Castabilities have been found to decrease with increase in Aloxy and to increase with increase in Ca content and Ca/Aloxy ratio. Reoxidation has been found not to affect the castability appreciably.
6

Modulação da resposta imune por antígenos da parede celular de Sporothrix schenckii em modelo murino de esporotricose

Ferreira, Lucas Souza [UNESP] 23 August 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-23Bitstream added on 2014-06-13T20:55:08Z : No. of bitstreams: 1 ferreira_ls_me_arafcf.pdf: 537259 bytes, checksum: 4756eac4f37ae0739a8b59e969ac32a1 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / A esporotricose é uma micose de distribuição universal cujo agente é o fungo termodimórfico Sporothrix schenckii. A forma mais comum da doença é a linfocutânea, que compromete pele, tecido subcutâneo e gânglios linfáticos regionais. Os principais constituintes da parede celular de S. schenckii são compostos peptídeo-polissacarídicos contendo ramnose, manose e galactose. Estes compostos se arranjam na parede celular de modo a formar duas subcamadas distintas na forma leveduriforme do fungo, uma das quais, a mais interna e fixa delas, é denominada como peptídeo-polissacarídeo da parede celular (PPC) e foi utilizada como antígeno neste estudo, juntamente com a levedura termo-inativada (SSTI). Os antígenos liberados pelo fungo participam diretamente do processo de escape do sistema imune e também servem como alvos para a eliminação do mesmo por anticorpos ou ligação a receptores presentes em células da imunidade inata, como os macrófagos. Nossos resultados mostraram que o PPC induz citocinas de padrão inflamatório de forma mais pronunciada que o SSTI, que por sua vez induziu maior liberação de IL-10. Sugerimos também que no modelo experimental utilizado a IL-10 não atua provocando supressão da resposta proliferativa dos esplenócitos, e que a IL-4 atua apenas na fase de resolução da infecção, não sendo induzida como forma de escape imunológico pelo fungo. Também mostramos que os antígenos testados são capazes de induzir a liberação de IL-17 em culturas de esplenócitos, num perfil semelhante àquela das citocinas Th1 / Sporotrichosis is a micotic infection of universal distribution, which is caused by dimorphic fungus Sporothrix schenckii. It usually happens as a lymphocutaneous disease, compromising skin, subcutaneous tissues and regional lymphatic nodules. Major constituents of S. schenckii cell wall are peptido-polysaccharide complexes containing rhamnose, mannose and galactose. These complexes are organized in two distinct layers in the fungus yeast cell wall, of which the inner one is called cell wall peptido-polysaccharide (PPC), being used as antigen in this study, along with the heat-killed yeast (SSTI). Antigens released by the fungus directly participate in evasion of the immune system, also serving as targets for fungus elimination by binding of antibodies or innate immune cells like macrophages. Our results showed that PPC induces inflammatory cytokines in a more pronounced way when compared to SSTI, which induced higher levels of IL-10. We also suggest that, in the animal model used, IL-10 doesn’t act as a suppressor of splenocyte proliferative response, and that IL-4 play a role at the resolution phase of the infection, being not induced as a means of immunologic escape by the fungus. Also, we showed that the assayed antigens are capable of inducing IL-17 secretion in splenocyte cultures, in a fashion close to that of Th1 cytokines
7

A study on molten steel/slag/refractory reactions during ladle steel refining

Jansson, Sune January 2005 (has links)
QC 20101203
8

A study on molten steel/slag/refractory reactions during ladle steel refining

Jansson, Sune January 2005 (has links)
No description available.
9

Příprava kampaně k propagaci zařízení autonomní detekce a signalizace v rámci preventivně výchovné činnosti na úseku požární ochrany / The preparation of campaign to promote an equipement of antonomous detection and signals in the framework of the preventive educational activities in the field of the fire protection

JARMAROVÁ, Lenka January 2013 (has links)
The preparation of campaign promoting autonomous detection and signaling devices within activities of preventive education in section of fire protection We can come across fires of buildings designed for living every day, therefore is very important to try to prevent them. The most accessible way is the installation of autonomous detection and signaling devices, which is currently obligatory to all newly designed and built houses. These devices detect emerging fire, subsequently inform about possible threat and at the same time they allow enough time for the population rescue. To achieve the main aims of thesis, it was needed to study specialized literature and write theoretical part which explains basic concepts connected to the topic, defines the dangers in the place of fire, followed by classification of toxic substances which are released during the fire and finally describes autonomous detection and signaling devices. The integral part contains the graphic layouts focused on the comparison of statistical data from 2001 till 2011, mostly tracking fires and number of killed and injured people during the household fires, which is compared to the number of killed and injured people and fires in general. There was made questionnaire for 50 public respondents from the city Zábřeh after completing the theoretical part. These respondents were chosen on purpose in cooperation with the fire station Zábřeh, which is part of Fire Rescue Service of Olomouc district. We defined hypothesis: The knowledge of Zábřeh population about own life and property protection against the fire are insufficient. The hypothesis was defined using descriptive and mathematical statistics. However, our hypothesis wasn´t confirmed so we can consider awareness of Zábřeh population to be sufficient but not excellent. Therefore, there is still need to increase their legal responsibility. The practical part further includes the analysis of questionnaire answers, which is aimed to evaluate the accuracy of answered questions. Last but not least, the thesis presents the set of promotional campaigns which are ordered by the ability to properly effect on the population via web pages, daily press, TV broadcast or printed materials. The most wanted way would be TV campaign, which is unfortunately expensive and time-consuming; therefore, it seems to be the best option to create web pages or printed material aimed for general public. The both promotional campaigns should be provided by Ministry of the Interior - general directorate of Fire Rescue Service of Czech Republic.
10

Modulação da resposta imune por antígenos da parede celular de Sporothrix schenckii em modelo murino de esporotricose /

Ferreira, Lucas Souza. January 2010 (has links)
Orientador: Iracilda Zeppone Carlos / Banca: Angela Maria Victoriano de Campos Soares / Banca: Eduardo Bagagli / Resumo: A esporotricose é uma micose de distribuição universal cujo agente é o fungo termodimórfico Sporothrix schenckii. A forma mais comum da doença é a linfocutânea, que compromete pele, tecido subcutâneo e gânglios linfáticos regionais. Os principais constituintes da parede celular de S. schenckii são compostos peptídeo-polissacarídicos contendo ramnose, manose e galactose. Estes compostos se arranjam na parede celular de modo a formar duas subcamadas distintas na forma leveduriforme do fungo, uma das quais, a mais interna e fixa delas, é denominada como peptídeo-polissacarídeo da parede celular (PPC) e foi utilizada como antígeno neste estudo, juntamente com a levedura termo-inativada (SSTI). Os antígenos liberados pelo fungo participam diretamente do processo de escape do sistema imune e também servem como alvos para a eliminação do mesmo por anticorpos ou ligação a receptores presentes em células da imunidade inata, como os macrófagos. Nossos resultados mostraram que o PPC induz citocinas de padrão inflamatório de forma mais pronunciada que o SSTI, que por sua vez induziu maior liberação de IL-10. Sugerimos também que no modelo experimental utilizado a IL-10 não atua provocando supressão da resposta proliferativa dos esplenócitos, e que a IL-4 atua apenas na fase de resolução da infecção, não sendo induzida como forma de escape imunológico pelo fungo. Também mostramos que os antígenos testados são capazes de induzir a liberação de IL-17 em culturas de esplenócitos, num perfil semelhante àquela das citocinas Th1 / Abstract: Sporotrichosis is a micotic infection of universal distribution, which is caused by dimorphic fungus Sporothrix schenckii. It usually happens as a lymphocutaneous disease, compromising skin, subcutaneous tissues and regional lymphatic nodules. Major constituents of S. schenckii cell wall are peptido-polysaccharide complexes containing rhamnose, mannose and galactose. These complexes are organized in two distinct layers in the fungus yeast cell wall, of which the inner one is called cell wall peptido-polysaccharide (PPC), being used as antigen in this study, along with the heat-killed yeast (SSTI). Antigens released by the fungus directly participate in evasion of the immune system, also serving as targets for fungus elimination by binding of antibodies or innate immune cells like macrophages. Our results showed that PPC induces inflammatory cytokines in a more pronounced way when compared to SSTI, which induced higher levels of IL-10. We also suggest that, in the animal model used, IL-10 doesn't act as a suppressor of splenocyte proliferative response, and that IL-4 play a role at the resolution phase of the infection, being not induced as a means of immunologic escape by the fungus. Also, we showed that the assayed antigens are capable of inducing IL-17 secretion in splenocyte cultures, in a fashion close to that of Th1 cytokines / Mestre

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