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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.
41

c-cytokromer hos den (per)kloratreducerande bakterien GR-1 : samt en jämförande studie av c-cytokromer från GR-1, Ideonella dechloratans och Dechloromonas aromatica

Palm, Eva-Lotta January 2007 (has links)
Arbetet beskriver en analys av innehållet av membranbundna och periplasmiska c-cytokromer hos perkloratodlade GR-1 och jämförelser med c-cytokrominnehållet hos Ideonella dechloratans och andra kända c-cytokromer, samt med genomet för Dechloromonas aromatica. Den jämförande studien av c-cytokromer gjordes med syftet att undersöka en hypotes om att bakterierna använder olika vägar för elektronöverföring till det periplasmiska enzymet (per)kloratreduktas. Cellmembran från GR-1 renframställdes genom ultracentrifugering och periplasma preparerades fram med hjälp av osmotisk chock. Fraktionerna analyserades sedan med SDS-PAGE och peptider med kovalent bundet hem (c-cytokromer) detekterades med hjälp av en specifik färgreaktion. Även Touchdown PCR med degenererade primrar genomfördes på isolerat DNA från GR-1 i ett försök att finna en gen kodande för ett NapC/NirT-liknande protein. Slutligen kolmonoxidbubblades reducerade membran för att undersöka förekomsten av cbb3-typ oxidas. Separation och infärgning av periplasmiska och membranbundna proteiner från GR-1 resulterade i sju respektive åtta peptidband med molekylvikter mellan 8-60 kDa. Inget som framkommit under arbetet talar emot hypotesen om att GR-1 och D. aromatica skulle använda ett NapC/NirT-liknande protein som elektronöverförare till det periplasmiska (per)kloratreduktaset. PCR-analysen resulterade i en produkt som troligtvis är en sekvens från en gen som kodar för ett NapC/NirT-liknande protein och två, eventuellt tre, kandidater för ett NapC/NirT-liknande protein hittades i membranet hos GR-1. Dessutom framkom att GR-1 troligtvis använder cbb3-typ oxidas som terminalt oxidas vid reduktion av syrgas under mikroaerofila förhållanden. Vad gäller I. dechloratans och hypotesen om att denna bakterie använder ett lösligt cytokrom c för elektronöverföring till sitt kloratreduktas så har inget framkommit under arbetet som talar emot detta. Tre kandidater för lösliga cytokrom c-proteiner hittades. För teorin talar även att de försök som tidigare gjorts med att påvisa genen för ett NapC/NirT-liknande protein hos denna bakterie gett negativt resultat. / This work describes an analysis of membrane-anchored and periplasmic c-type cytochromes of perchlorate grown GR-1, and a comparison with the c-type cytochrome content of Ideonella dechloratans, other known c-type cytochromes and the genome of Dechloromonas aromatica. The aim of the comparison was to investigate a hypothesis that the bacteria use different routes for electron transfer to the periplasmic enzyme (per)chlorate reductase. Cell membrane from GR-1 was prepared through ultracentrifugation and periplasm was prepared through osmotic chock. The fractions were separated by SDS-PAGE and peptides containing covalently bound heme (c-type cytochromes) were detected by a specific staining reaction. In an attempt to probe a gene coding for a NapC/NirT-like protein Touchdown PCR was performed on isolated DNA from GR-1, using degenerate primers. Finally, reduced membranes were treated with carbon monoxide to investigate the presence of cbb3-type oxidase. Separation and detection resulted in seven periplasmic peptides and eight membrane anchored peptides, all with molecular weights in a range of 8-60 kDa. Nothing has been revealed during this work that opposes the hypothesis of GR-1 and D. aromatica using a NapC/NirT-like protein as an electron carrier to their periplasmic (per)chlorate reductase. The PCR resulted in a product that most likely is a sequence from a gene coding for a NapC/NirT-like protein and two, maybe three, candidates for a NapC/NirT-like protein were also found in the membrane of GR-1. Analysis also revealed that GR-1 most likely makes use of a cbb3-type oxidase for reduction of oxygen during microaerofilic conditions. Concerning I. dechloratans, nothing has been revealed during this work that opposes the hypothesis of this bacterium using a soluble cytochrome c as an electron carrier to its chlorate reductase. Three candidates for a soluble cytochrome c protein were found. The theory is also supported by the negative result from earlier attempts to probe a gene coding for a NapC/NirT-like protein in this bacterium.
42

Monitoramento das m?dias de um processo bivariado por gr?ficos de controle por atributos e/ou vari?veis

Melo, Moiz?s da Silva 18 February 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-27T00:29:23Z No. of bitstreams: 1 MoizesDaSilvaMelo_DISSERT.pdf: 1403747 bytes, checksum: d910e8743f2cf3fa46d99902729b8c73 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-09-02T20:06:24Z (GMT) No. of bitstreams: 1 MoizesDaSilvaMelo_DISSERT.pdf: 1403747 bytes, checksum: d910e8743f2cf3fa46d99902729b8c73 (MD5) / Made available in DSpace on 2016-09-02T20:06:24Z (GMT). No. of bitstreams: 1 MoizesDaSilvaMelo_DISSERT.pdf: 1403747 bytes, checksum: d910e8743f2cf3fa46d99902729b8c73 (MD5) Previous issue date: 2016-02-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A alta variabilidade de um processo est? diretamente relacionada com a m? qualidade do mesmo, portanto, reduzi-la ? a maneira de melhorar o processo. Os m?todos estat?sticos est?o inclu?dos ao planejamento de melhoria de processos, dentre os quais os gr?ficos de controle s?o o mais eficientes e utilizados. Esta disserta??o prop?e dois novos gr?ficos de controle para monitorar um vetor de m?dias de um processo bivariado. O primeiro, chamado de new npxy, emprega um gr?fico por atributos. O procedimento consiste em inspecionar e classificar, atrav?s dos limites discriminantes, cada unidade da amostra como aprovada ou reprovada. Os limites discriminantes s?o ajustados de tal forma que tem-se uma fra??o especificada de unidades reprovadas quando o processo est? sob controle. Em seguida o n?mero de unidades reprovadas ? plotado no gr?fico, e caso seja maior que o limite de controle, o processo ? parado para ajuste. O segundo gr?fico utiliza os gr?ficos new npxy e T2. Este procedimento consiste em dividir uma amostra de tamanho $n$ em duas partes (n1 e n2), determinadas por um processo de otimiza??o. As unidades da primeira sub-amostra s?o avaliadas por atributos e plotadas em um gr?fico de controle new npxy. Caso seja detectada a presen?a de alguma causa especial, inspeciona-se a sub-amostra de tamanho n2 por vari?veis por meio do gr?fico T2. O procedimento ? interrompido para o ajuste se a presen?a de alguma causa especial for detectada em ambos gr?ficos de controle. A possibilidade de n?o inspecionar todos os itens da amostra pode promover uma redu??o tanto no custo quanto no tempo de inspe??o. A an?lise de desempenho foi realizada comparando o n?mero m?dio de amostras at? o alarme verdadeiro (NMA1). Verificou-se que os gr?ficos propostos apresentam desempenho satisfat?rio e s?o concorrentes com o gr?fico T2. Os resultados foram obtidos com o aux?lio do software estat?stico R.
43

Efeitos da desnutrição proteica pós-natal no funcionamento do eixo hipotálamo-hipófise-adrenal em ratos submetidos ao enriquecimento ambiental / EFFECTS OF EARLY PROTEIN MALNUTRITION IN THE OPERATION OF HYPOTHALAMIC-PITUITARY-ADRENAL IN RATS SUBMITTED TO ENVIRONMENTAL ENRICHMENT

Roberto de Oliveira Soares 19 April 2013 (has links)
Ratos submetidos à desnutrição proteica apresentam elevada impulsividade e alterações em comportamentos de avaliação de risco no labirinto em cruz elevado (LCE). A desnutrição também pode influenciar a atividade do eixo hipotálamo-hipófise-adrenal (HPA). Alterações causadas pela desnutrição podem ser parcialmente revertidas pela estimulação ambiental; animais desnutridos e submetidos ao enriquecimento ambiental apresentaram maior locomoção e exploração no LCE, comparados com animais de mesma condição de dieta e que não foram estimulados. Demonstrou-se também que a estimulação pode influenciar os níveis de corticosterona plasmática evidenciando uma alteração da sensibilidade do eixo HPA. Este trabalho tem o objetivo de comparar, em ratos desnutridos (M) e bem nutridos (C), os efeitos do enriquecimento ambiental (E) em relação às concentrações de corticosterona plasmática, expressão de receptores de glicocorticóides (GR) no hipocampo e o desempenho no LCE aos 36 dias de idade. Ratos Wistar machos foram divididos em dois grupos de acordo com a dieta e subdivididos em subgrupos conforme a manipulação ambiental. A manipulação ambiental foi realizada no período de 8 a 35 dias (1 hora por dia). Após o teste no LCE os animais foram decapitados e tiveram o sangue coletado e o cérebro removido. Para a análise de corticosterona plasmática foi utilizada a técnica de radioimunoensaio. Para a quantificação dos receptores (GR) no hipocampo foi realizada uma análise quantitativa de expressão gênica por meio da reação em cadeia da polimerase (PCR) em tempo real. Ratos M apresentaram menor peso corporal quando comparados com os ratos C (p<0,001). Em relação ao LCE, ratos M permaneceram uma maior porcentagem de tempo [F(1,44)=9,08; p<0,01] e entraram mais [F(1,44)=9,01; p<0,01] nos braços abertos em relação a C. Animais ME apresentaram porcentagem de tempo nos braços abertos (6% ± 2%) próxima àquela dos animais CN (8% ± 2%). De acordo com a PCR em tempo real, o teste do LCE alterou a quantidade de receptores GR no hipocampo (t(10)=2,37; p<0,05) e essa adaptação ocorreu diferentemente em ratos M quando comparados com os C. Também foi possível observar que a quantidade de receptores GR após o teste do LCE é diferente entre os grupos M e ME (t(11)=4,48; p<0,05). Os dados do presente estudo sugerem que animais desnutridos se expõem a mais situações de risco que ratos bem nutridos. Quando o enriquecimento ambiental foi realizado no período crítico do desenvolvimento do sistema nervoso central observou-se um efeito de neuroproteção em relação às alterações produzidas pela desnutrição tanto na expressão de RNAm de receptores GR como no comportamento de avaliação de risco de ratos no LCE. Os dados do presente trabalho também mostraram que a desnutrição pode alterar a resposta de estresse mediada pelo eixo HPA após exposição ao teste do LCE, e que o enriquecimento ambiental possui efeito protetor em relação os efeitos da desnutrição precoce sobre a atividade deste eixo / Rats subjected to protein malnutrition have high impulsivity and changes in risk-assessment behaviors in the elevated plus maze (EPM). Malnutrition can also influence the activity of the hypothalamic-pituitary-adrenal (HPA). Changes caused by malnutrition can be partly reversed by environmental stimulation; malnourished animals subjected to environmental enrichment had higher locomotion and exploration in the EPM compared with animals of the same condition and diet that were not stimulated. It was also demonstrated that stimulation can influence plasma corticosterone levels indicating a change in sensitivity of the HPA axis. This study aims to compare, in undernourished rats (M) and well nourished (C), the effects of environmental enrichment (E) in relation to plasma concentrations of corticosterone, expression of glucocorticoid receptors (GR) in the hippocampus and performance in EPM at 36 days of age. Male Wistar rats were divided into two groups according to diet and subdivided according handling environment. The environmental manipulation was performed within 8 to 35 days (1 hour per day). After testing in the EPM animals were decapitated and had their blood drawn and the brain removed. For the analysis of plasma corticosterone it was used the radioimmunoassay technique. For quantification of the glucocorticoid receptor (GR) in the hippocampus it was performed a quantitative analysis of gene expression by polymerase chain reaction (PCR) in real time. M rats showed lower body weight compared to C rats (p<0.001). In relation to the EPM, M rats showed higher number of entries [F(1,44)=9.01, p<0.01] and remain a higher percentage of time [F(1,44)=9.08, p<0.01] in the open arms as compared to C. ME rats presented a percentage of time in the open arms (6% ± 2%) similar to that of CN animals (8% ± 2%). According to the real time PCR, the EPM test changed the quantity of GR receptors in the hippocampus (t(10)=2.37, p<0.05), and that adaptation was different in M as compared with C rats. It was also observed that the amount of GR after EPM test was different between M and ME groups (t(11)=4.48, p<0.05). Data from the present study suggest that M animals are more likely to explore risk situations than C rats. It is also suggested that environmental enrichment imposed during the critical period of central nervous system development may have neuroprotective effects in both physiological and behavioral changes produced by early protein malnutrition. The data of this work also showed that malnutrition may alter the stress response mediated by the HPA axis after exposure to the EPM test and that environmental enrichment has a protective effect against the effects of malnutrition on the functioning of that axis.
44

Produ??o de gr?s porcelanato a partir de mat?rias-primas do Rio Grande do Norte e queima a g?s natural / Production of porcelainized stoneware tiles from raw materials of the State of Rio Grande do Norte and burns the natural gas

Pinheiro, Andr?a Santos 19 May 2006 (has links)
Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 AndreaSP.pdf: 1820286 bytes, checksum: a1263199151d8fb3f317fa86bacf6014 (MD5) Previous issue date: 2006-05-19 / The State of Rio Grande do Norte, Brazil, possess major deposits of feldspar, clay, kaolin and talc, all raw materials used in the production of porcelainized stoneware tiles. Conversely, state industries manufacture only low added value red ceramics. Porcelainized stoneware tiles is one of the noblest ceramics, depicting low water absorption (typically below of 0,5%), in addition to excellent staining resistance and mechanical strength. The present work aims at investigating the potential of local raw materials for the production of porcelainized stoneware tiles. To that end, these materials were characterized by X-ray fluorescence, X-ray diffraction, particle size analysis, thermal gravimetric analysis and thermal differential analysis. Admixtures containing different compositions were prepared and fired at three temperatures, 1150, 1200 and 1250?C for 30 min. After firing, tests samples were characterized by water absorption tests, linear retraction, dilatometric analysis, apparent porosity, apparent specific mass, flexural strength, and microstructural analysis by XRD and SEM. The results revealed that ceramics with porcelainized stoneware tiles characteristics could be produced from raw materials originated in the State of Rio Grande do Norte / O Rio Grande do Norte possui grandes jazidas de pegmatitos, argilas caulin?ticas e caulim, principais mat?rias-primas para a fabrica??o de gr?s porcelanato. No entanto, o RN produz apenas produtos de baixo valor agregado em rela??o ao porcelanato, uma das mais nobres cer?micas de revestimento, devido a sua baixa absor??o d??gua (tipicamente abaixo de 0,5%), al?m de apresentar excelentes caracter?sticas t?cnicas, destacando-se elevada resist?ncia mec?nica, ao risco e ao manchamento. O presente trabalho tem a finalidade de validar o potencial de mat?rias-primas do RN (feldspato, argila, caulim e talco beneficiado) para a produ??o de gr?s porcelanato. Para isso, foi feita a caracteriza??o das mat?rias primas por FRX, DRX, AG, ATG e ATD, elaborando-se cinco formula??es que foram queimadas em tr?s temperaturas: 1150, 1200 e 1250?C com 30 minutos de patamar. Ap?s a queima, os corpos-de-prova foram submetidos a ensaios de absor??o de ?gua, retra??o linear, porosidade aparente, massa espec?fica aparente, resist?ncia ? flex?o, DRX, MEV e an?lise dilatom?trica. Obteve-se para uma das misturas, propriedades compat?veis com as exigidas para um gr?s porcelanato
45

Implication du récepteur des glucocorticoïdes en physiopathologie humaine / Involvement of the Glucocorticoid Receptor in Human Disease

Vitellius, Géraldine 04 October 2019 (has links)
Les glucocorticoïdes (GC), généralement sécrétés par le cortex surrénalien, exercent de très nombreuses fonctions dans l’organisme, via leur liaison au récepteur des glucocorticoïdes (GR). Les rares mutations inactivatrices du GR déjà décrites, sont responsables d’un syndrome de résistance aux GC et peuvent conduire à une hypertension artérielle (HTA), une hyperplasie surrénalienne (HBS), un hirsutisme et une obésité. Dans ce travail, nous avons caractérisé fonctionnellement 13 variants hétérozygotes du GR (expression, transactivation, localisation subcellulaire,...). Six variants du GR, découverts par séquençage à haut débit (NGS) ne sont pas pathogènes alors que 7 mutations hétérozygotes originales délétères ont été identifiées dans le cadre du protocole hospitalier de recherche clinique (Muta-GR). Ce PHRC a permis de préciser une prévalence à 5% de mutations inactivatrices du GR dans une cohorte de 100 patients avec HBS associée à une HTA et/ou un hypercortisolisme biologique sans signe clinique de Cushing.Une haploinsuffisance du GR, démontrée par la diminution d’induction par la déxamethasone du gène cible FKBP5, a été mise en évidence dans les fibroblastes cutanés de certains patients porteurs de mutations inactivatrices du GR. Ces patients présentent souvent un hypercorticisme avec hypokaliémie, aldostérone et rénine basse, signant un pseudohyperaldostéronisme. Nous avons démontré que le gène HSD11B2 codant pour l’enzyme 11β-HSD2, assurant l’inactivation des GC, est une cible directe du GR comme démontré par transfection transitoire de gène-rapporteur, RT-qPCR, LC/MSMS et ChIP. L’établissement des modèles de knock-in de mutations GR par stratégie Crispr/cas9 dans des lignées cellulaires préadipocytaires ou corticosurrénaliennes humaines s’est soldé par un échec. Ce travail devrait faciliter la sélection des patients chez qui la recherche de mutation inactivatrice du GR doit être faite et invite à un suivi régulier de ces patients. / Glucocorticoids (GC) regulate many essential biological functions by activating the glucocorticoid receptor (GR). GR loss-of function mutations are responsible for GC resistance syndrome, often associated with high blood pressure, hirsutism, bilateral adrenal hyperplasia (BAH) and obesity. Herein, functional characterization of 13 GR variants is presented (expression and binding studies, transactivation assays, subcellular localization) 6 variants were discovered with next-generating sequencing and had no functional impact on GR signaling while 7 GR loss-of-function mutations were mainly discovered during the National Clinical Hospital Research Program, Muta-GR. This PHRC discloses a 5% prevalence of GR loss-of-function mutations in a cohort of 100 patients with BAH, biological hypercortisolism and/or hypertension without Cushing signs. A GR haploinsuffisiency was demonstrated by a reduced dexamethasone-induced FKBP5 expression in skin fibroblasts of some patients harbouring GR loss-of-function mutations. These patients often presented with hypercorticism, hypokalemia, low renin and aldosterone levels, consistent with a pseudohypermineralocorticism. We showed that HSD11B2 encoding the 11β-HSD2 enzyme inactivating GC, is a direct GR target gene by transient transfection of reporter gene, RT-qPCR, LC/MSMS and ChIP. We failed to introduce GR loss-of-function mutations in human preadipocytes and adrenocortical cells by Crispr/Cas 9 technology. This work should facilitate selection of patients in whom GR mutation may be search, enabling an appropriate follow-up.
46

An analysis of toponyms and toponymic patterns in eight parishes of the upper Kelvin basin

Drummond, Peter John January 2014 (has links)
This thesis examines a small but unfashionable area of Scotland, invisible to tourist guidebooks, heavily urbanised, and whose towns have won environmental ‘Carbuncle awards’ from the Scottish media. Yet it is deep in Gaelic and Scots place-names which reveal a landscape that past inhabitants perceived to be a green and relatively pleasant land, if perhaps not flowing with milk and honey. Part Three belies its numeration, in that it is the core of the study, examining in detail the place-names of eight (modern) parishes, listing old forms and attempting a sound etymology for each. Part One, based on the data gathered for Part Three, attempts to seek patterns among these names, both between and within the languages concerned. Inter alia, it seeks to explore the degree to which the choice of elements for a particular name, from any language’s toponymicon, is conditioned by cultural, political and social influences ranging from feudal and parochial authorities, through the influence of Scots-speaking merchants, to onomastic local farming customs. The lessons derived from Part One were then used to shed light on some etymologies in Part Three: and hopefully will be of value to researchers in other areas of the country.
47

The Effect of Lactobacillus rhamnosus GR-1 Supernatant on Cytokine Production and Prostaglandins in Gestational Tissues

Yeganegi, Maryam 18 January 2012 (has links)
Preterm birth remains a major challenge in obstetrics. It complicates up to 13% of all pregnancies and accounts for approximately 80% of neonatal mortality and morbidity. Bacterial Vaginosis (BV) is associated with a 1.4-fold increased risk of preterm birth. Due to ineffectiveness of antibiotics in preventing preterm labour, probiotics have been proposed to serve as an alternative for treatment of BV and prevention of preterm birth. The objectives of this thesis were to determine 1) the effect of Lactobacillus rhamnosus GR-1 (L. rhamnosus GR-1) supernatant on cytokine profile and prostaglandin (PG)-regulating enzyme expression in lipopolysaccharide (LPS)-stimulated human chorion and placental trophoblast cells from human placentae, 2) the potential signaling pathways through which lactobacilli act and 3) the potential role of immune and placental trophoblast cells in initiating a response to LPS and L. rhamnosus GR-1 treatments. Primary cultures of human placental trophoblast cells were pre-treated with lactobacilli supernatant and then with LPS. In addition, immune cells were removed from cell suspensions using a magnetic purification technique to determine their role in modulating cytokine levels. The expression of pro- and anti-inflammatory cytokines and prostaglandin-regulating enzymes was then determined. We found sex-specific differences in the ability of LPS to increase the output of TNF-α, IL-10, and PTGS2. We also showed that L. rhamnosus GR-1 is able to act through the JAK/STAT and MAPK pathways to increase IL-10 and G-CSF, and independently down-regulates PTGS2 and TNF-α and up-regulates PGDH. The increase in G-CSF and PGDH were only observed in women carrying a female fetus. L. rhamnosus GR-1 may serve as an alternative to antibiotics in preventing some infection/inflammation-mediated cases of preterm birth.
48

Teaching practices for the development of the problem solving skills of gr 9 natural sciences learners / Ann Elizabeth Vicente

Vicente, Ann Elizabeth January 2013 (has links)
A goal of Natural Sciences education is to ensure that learners become scientifically literate. Scientific literacy refers to learners‟ ability to solve problems that relate to policies and practices that affect the natural world. To achieve this goal, teachers need to ensure that their learners become effective problem solvers. This study explored the nature of teaching and assessment practices for the development of the problem solving skills of Gr 9 Natural Sciences learners and makes recommendations to support teachers in this regard. Quantitative, descriptive, survey research was conducted, by means of a structured questionnaire, with Gr 9 Natural Sciences teachers in the Sedibeng West District (D8) of Gauteng, South Africa. The findings of the study show there is a need for improving teaching and assessment practices for the development of the problem solving skills of Gr 9 Natural Sciences learners. Scientific Inquiry is a process known to develop the problem solving skills of learners. This process requires that learners employ critical and creative thinking as well as Science process skills as they make observations, pose questions, perform research and support the process with experimental evidence obtained from a Scientific Investigation as they search for solutions to problems. Although teachers acknowledge that Scientific Inquiry assists in developing the problem solving skills of learners they appear to have a limited view of the implementation thereof. Instead of using Scientific Inquiry to help learners build scientific theories and models when addressing problems, teachers‟ appear to favour the traditional Scientific Method. This method supports the notion that “doing Science means doing experiments” and problem solving becomes reduced to a sequence of steps performed to reinforce Natural Sciences concept and content objectives. Other problems associated with the implementation of Scientific Inquiry include limited classroom discussions surrounding Scientific Investigations as well as teachers favouring demonstrations instead of learners performing their own Scientific Investigations. Also, resources for Scientific Investigations appear to be in short supply and teachers experience difficulty in managing large class sizes during Scientific Investigations. Gr 9 Natural Sciences teachers invest time and effort in their learners‟ development and show dedication to the task of imparting their Natural Sciences knowledge and skills to their learners. If such teachers were to align their teaching and assessment practices with the process of Scientific Inquiry then a high degree of success would be achieved in developing the problem solving skills of Gr 9 Natural Sciences learners. / MEd (Learning and Teaching), North-West University, Vaal Triangle Campus, 2013
49

Estudo experimental do comportamento à fratura frágil em aços estruturais ferríticos e aplicações à determinação da curva mestra. / Experimental study on the cleavage fracture behavior of structural ferritic steels and applications to determine the master curve.

Savioli, Rafael Guimarães 13 April 2016 (has links)
Este trabalho apresenta uma investigação experimental sobre o comportamento à fratura frágil de aços estruturais ferríticos, ASTM A285 Gr C e ASTM A515 Gr 65. Os resultados deste trabalho ampliam a base de dados de propriedades mecânicas utilizadas nas análises de integridade de estruturas pressurizadas tais como vasos de pressão e tanques de armazenamento construídos com esta classe de material. O trabalho tem por objetivo também avaliar a aplicabilidade de corpos de prova de dimensões reduzidas, PCVN, na determinação da temperatura de referência, T0, por meio da metodologia da Curva Mestra, a qual define a dependência da tenacidade à fratura do material em função da temperatura. Os ensaios de tenacidade à fratura foram conduzidos utilizando-se corpos de prova solicitados em flexão três pontos com geometria SE(B), PCVN e PCVN com entalhe lateral, extraídos de chapas laminadas. Os resultados dos ensaios foram obtidos em termos de integral J no momento da instabilidade, denotados por Jc. Dados adicionais de resistência à tração e de Impacto Charpy convencional também foram obtidos para caracterizar o comportamento mecânico dos aços utilizados. Os resultados mostraram uma forte influência da geometria dos corpos de prova sobre os valores de Jc, evidenciada pela grande variação nos valores de tenacidade à fratura. / This work presents an experimental investigation on the cleavage fracture behavior of structural ferritic steels, ASTM A285 Grade C and ASTM A515 Grade 65. One purpose of this study is to enlarge a previously reported work on mechanical and fracture properties for this class of steel to provide a more definite database for use in structural and defect analyses of pressurized components, including pressure vessels and storage tanks. Another purpose is to address the applicability of Precracked V-notch Charpy specimens to determine the reference temperature, T0, derived from the Master Curve Methodology which defines the dependence of fracture toughness with temperature for the tested material. Fracture toughness testing conducted on single edge bend specimens in three-point loading (SE(B), PCVN Plain Side and PCVN Side Grooved) extracted from laminated plates provides the cleavage fracture resistance data in terms of the J-integral at cleavage instability, Jc. Additional tensile and conventional Charpy tests produce further experimental data which serve to characterize the mechanical behavior of the tested materials. The results reveal a strong effect of specimen geometry on Jc values associated with large scatter in the measured values of cleavage fracture toughness.
50

Reconstructing John Hick's theory of religious pluralism : a Chinese folk religion's perspective

Wong, Wai Yip January 2012 (has links)
Hick’s pluralist assumption has remained the most knowable model of religious pluralism in the last few decades. Many have, from the perspectives of various major world religions, questioned his notion that the teachings of all religions are derived from the same Absolute Truth and that salvific-end is one, yet little attention has been paid to the traditions that he graded as unauthentic and non-valuable according to his soteriological and ethical criteriology. The purpose of this thesis was to demonstrate the exclusiveness of Hick’s model by describing a tradition called “Chinese Folk Religion” that does not fit into his definition of ‘authentic religion’. As the study suggested, his understanding of the world religious situation is over-generalised and simplified, and his particular criteriology does not treat all traditions fairly or pluralistically. As a response, this thesis proposed a more inclusive theory that also integrates the currently disregarded tradition into the interpretation.

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