Massive sulfide deposits in the Noranda mining camp, northwestern Québec, are mainly associated with extensive footwall alteration defined by intense chloritization and sericitization. However, Fe-carbonate alteration also occurs in proximity to some deposits. To test the exploration significance of carbonate alteration in the camp, two areas of intense carbonate alteration were examined, around the small Delbridge deposit and near the new Pinkos occurrence in the Cyprus Rhyolite. Between 1969 and 1971, the Delbridge deposit produced 370,000 t of ore grading 9.6% Zn, 0.61% Cu, 110 g/t Ag, and 2.1 g/t Au. Recent drilling at the new Pinkos occurrence intersected 2.64 m of massive to semi-massive sulfides grading 8.1% Zn and 18.2 g/t Ag. Alteration mapping has shown that the distribution of Fe-carbonates can be used to identify vertically extensive zones of hydrothermal upflow at both properties. At Delbridge, intense Fe-carbonate alteration in brecciated rhyolite defines a pipe-like upflow zone that extends vertically for up to 300 m within the stratigraphic footwall of the massive sulfides and 100 m into the hanging wall. The location of known massive sulfide mineralization coincides with the intersection of the alteration pipe and a favorable horizon marked by the occurrence of fine-grained volcaniclastic rocks. At Pinkos, a similar zone of Fe-carbonate alteration occurs in outcrops of coherent rhyolite. Fe-carbonate alteration is most intensely developed along polygonal cooling fractures in massive rhyolite and decreases in intensity towards the centers of the columns. Fe-carbonate stringers and locally abundant matrix carbonate occur in fragmental rocks at the stratigraphic top of the coherent rhyolite flows and are most intense at the location of sulfide-bearing outcrops that mark the known mineralized horizon. Whereas Fe-carbonate alteration defines the central part of the hydrothermal upflow zones at both properties, disseminated pyrite occurs at the margins and is widespread outside the main upflow zones. This may indicate that Fe-carbonate in the main upflow zones formed at the expense of earlier disseminated sulfides. Replacement of pyrite by synvolcanic Fe-carbonate alteration at Delbridge and Pinkos can probably be attributed to a relatively high concentration of dissolved CO2, possibly of magmatic origin, in the main-stage ore-forming fluids.

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2017-11-09T11:36:10Z No. of bitstreams: 0 / Made available in DSpace on 2017-11-09T11:36:10Z (GMT). No. of bitstreams: 0 / Revestimentos superficiais são aplicados à muitas ferramentas de usinagem na indústria metalúrgica com o intuito de melhorar a eficiência de corte e aumentar sua vida útil. Neste trabalho foram realizados testes para remoção do recobrimento de nitreto de titânio alumínio (TiAlN) em pastilhas de carboneto de tungstênio (WC-Co), utilizando um feixe laser de pulsos ultracurtos. Após a determinação dos limiares de dano do filme e do substrato foram ablacionados na superfície do recobrimento, traços utilizando duas condições de ablação. Inicialmente operou-se no regime de baixa fluência do filme, e posteriormente no regime de baixa fluência do substrato, muito abaixo do limiar do filme, aplicando-se alta sobreposição de pulsos. Um sistema de espectroscopia de emissão atômica induzida por laser (LIBS) foi montado para monitoramento dos materiais presentes no plasma gerado pelo laser, porém o sistema não apresentou sensibilidade suficiente para leitura da baixa intensidade do plasma proveniente do processo e não foi utilizado. Após a análise dos traços por microscopia eletrônica, perfilometria óptica e espectroscopia por fluorescência de Raios-X, não foi possível determinar um processo seguro para realizar a remoção seletiva do filme em questão, porém, devido aos dados obtidos e observações dos resultados em alguns traços, novas possibilidades foram levantadas, abrindo a discussão para a realização de trabalhos futuros. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Aufgrund der komplexen Strahler-Werkstoff-Wechselwirkung beim Erwärmen von Kunststoffen mit Infrarotstrahlung ist in vielen Infrarotschweißprozessen eine Rauchentwicklung zu beobachten. Diese tritt oftmals bei ruß- und/oder glasfasergefüllten Kunststoffen auf und resultiert in einem thermisch-oxidativen Werkstoffabbau, welcher zu einer Abnahme der mechanischen und thermischen Verbindungseigenschaften führt. Die Rauchbildung kann zudem lufttechnische Maßnahmen, wie Absaugeinrichtungen, an der Schweißmaschine erforderlich machen. Der Problematik der Rauchentwicklung beim Infrarotschweißen (IR-Schweißen) von Kunststoffen wird derzeit mit zeitintensiven, empirischen Voruntersuchungen zur Parameterfindung entgegengewirkt. Ziel ist es Strahlerabstands-Erwärmzeit-Kombinationen zu finden, die zu einer ausreichenden Schmelzeerzeugung bei möglichst niedriger thermisch-oxidativer Werkstoffbelastung führen. Ein Ansatz zur Reduzierung des Vorversuchsaufwandes ist die Temperaturmessung der bestrahlten Substratoberfläche, welche unterhalb der Zersetzungstemperatur des bestrahlten Kunststoffs liegen sollte. Derzeitig können jedoch nur ergänzende thermographische und pyrometrische Temperaturmesssysteme eingesetzt werden, welche eine vergleichende Messung der Prozesstemperaturen beim IR-Schweißen ermöglichen und die Prozessstabilität des IR-Schweißprozesses in einem festgelegten Prozessfenster gewährleisten. Eine Messung der tatsächlichen Kunststofftemperaturen ist mit diesen Systemen nicht möglich. Aktuell hat eine Änderung der zu schweißenden Kunststoffe, der Füllstoffe (z. B. Glasfasern) oder ein Schwanken der Füll-und Verstärkungsstoffgehalte der Kunststoffe zur Folge, dass neue Voruntersuchungen zur Prozessparameterfindung des IR-Schweißprozesses notwendig werden. Aufgrund dessen entwickeln die Professur Kunststoffe an der Technischen Universität Chemnitz und die Firma Eugen Riexinger aus Bad Liebenzell eine Temperaturmessmethodik zur Bestimmung der tatsächlich auftretenden Substrattemperaturen während der Infraroterwärmung von Kunststoffen. Die Methodik soll eine IR-Erwärmung von Kunststoffen auf eine kunststoffabhängige Soll-Temperatur ermöglichen und verhindert so die Rauchbildung während der IR-Erwärmung und damit die thermisch-oxidative Werkstoffschädigung. Der Beitrag beschreibt die aktuell auftretenden Herausforderungen beim IR-Schweißen von Kunststoffen, die gewählte Herangehensweise an die Entwicklung der Temperaturmessmethodik zur Bestimmung der tatsächlichen Substrattemperatur sowie die Ergebnisse des Entwicklungsprozesses.

Massive sulfide deposits in the Noranda mining camp, northwestern Québec, are mainly associated with extensive footwall alteration defined by intense chloritization and sericitization. However, Fe-carbonate alteration also occurs in proximity to some deposits. To test the exploration significance of carbonate alteration in the camp, two areas of intense carbonate alteration were examined, around the small Delbridge deposit and near the new Pinkos occurrence in the Cyprus Rhyolite. Between 1969 and 1971, the Delbridge deposit produced 370,000 t of ore grading 9.6% Zn, 0.61% Cu, 110 g/t Ag, and 2.1 g/t Au. Recent drilling at the new Pinkos occurrence intersected 2.64 m of massive to semi-massive sulfides grading 8.1% Zn and 18.2 g/t Ag. Alteration mapping has shown that the distribution of Fe-carbonates can be used to identify vertically extensive zones of hydrothermal upflow at both properties. At Delbridge, intense Fe-carbonate alteration in brecciated rhyolite defines a pipe-like upflow zone that extends vertically for up to 300 m within the stratigraphic footwall of the massive sulfides and 100 m into the hanging wall. The location of known massive sulfide mineralization coincides with the intersection of the alteration pipe and a favorable horizon marked by the occurrence of fine-grained volcaniclastic rocks. At Pinkos, a similar zone of Fe-carbonate alteration occurs in outcrops of coherent rhyolite. Fe-carbonate alteration is most intensely developed along polygonal cooling fractures in massive rhyolite and decreases in intensity towards the centers of the columns. Fe-carbonate stringers and locally abundant matrix carbonate occur in fragmental rocks at the stratigraphic top of the coherent rhyolite flows and are most intense at the location of sulfide-bearing outcrops that mark the known mineralized horizon. Whereas Fe-carbonate alteration defines the central part of the hydrothermal upflow zones at both properties, disseminated pyrite occurs at the margins and is widespread outside the main upflow zones. This may indicate that Fe-carbonate in the main upflow zones formed at the expense of earlier disseminated sulfides. Replacement of pyrite by synvolcanic Fe-carbonate alteration at Delbridge and Pinkos can probably be attributed to a relatively high concentration of dissolved CO2, possibly of magmatic origin, in the main-stage ore-forming fluids.

Physical activity results in various types of stress in skeletal muscle including energetic, oxidative, and heat stress. Acute exposure to stress impairs skeletal muscle mitochondrial function. In contrast, chronic intermittent exposure to mild stress through exercise training results in increased mitochondrial content and respiratory capacity. While oxidative and energetic stress have received much attention regarding their long-term effect on skeletal muscle mitochondria, heat stress is not well understood. The purpose of this work was to investigate the effects of localized heat therapy on human skeletal muscle mitochondria, and to compare these effects to those of high-intensity interval exercise training. To accomplish this purpose, 35 subjects were assigned to receive 6 weeks of sham therapy, heat therapy, or exercise training; all localized to the quadriceps muscles of the right leg. Two-hour sessions of short-wave diathermy were used for the heat therapy, and identical sessions were used for sham therapy, but the diathermy units were not activated. Forty-minute sessions of single-leg extension, high-intensity interval training were used for the exercise intervention. All interventions took place three times per week. Muscle biopsies were performed at baseline, and after three and six weeks of intervention. Muscle fiber bundles were isolated and permeabilized for measurement of oxygen consumption via high-resolution respirometry. The primary finding of this work was that heat therapy improves mitochondrial respiratory capacity by 24.8 ± 6.2% compared to a 27.9 ± 8.7% improvement following exercise training. Both heat and exercise significantly increased mitochondrial respiration compared to baseline measures (p<0.05). Fatty acid oxidation and citrate synthase activity were also increased following exercise training by 29.5 ± 6.8% and 19.0 ± 7.4%, respectively (p<0.05). However, contrary to our hypothesis, heat therapy did not increase fatty acid oxidation or citrate synthase activity. Neither heat nor exercise training increased mitochondrial respiratory protein content. Overall these results suggest that heat therapy significantly improves mitochondrial function, but not to the same degree as exercise training.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2002. / 198 leaves double sided printed, preliminary pages i-xx and numberd pages 1-1-12-6.Includes bibliography. List of tables, figures and appendices and acronyms. Scanned with a HP Scanjet 8250 Scanner to pdf format (OCR). / ENGLISH ABSTRACT: In this study the numerical short wave model SWAN is evaluated for application to a selected coastal region in South Africa. The aim of this study was to evaluate the degree of accuracy with which SWAN can simulate prototype nearshore wave spectra and wave parameters (e.g. wave height, mean wave direction and mean wave period) for an Algoa Bay field case. Algoa Bay represents a typical deep, sheltered embayment on the South African south coast, which is exposed to high-energy swell. Sensitivity analyses on various wave-related processes were also done, with the aim of establishing the dominant physical processes and appropriate model setup for the Algoa Bay field case. With the dominant wave-related processes and appropriate model setup for the Algoa Bay field case established, selected final runs were performed to determine the degree of accuracy with which SWAN can simulate prototype conditions, by comparing its results with available field recordings. This study comprises a review of the SWAN evaluation work conducted to date by others, an overview of South African coastal conditions, and numerical model simulations. The model simulations, which represent the main focus of this study, were conducted for a selection of available offshore wave conditions (at 85 m water depth) observed during the Algoa Bay field case and were compared to available nearshore observations (at 17 m water depth). Environmental conditions of waves, wind and currents were included in these simulations. The study focuses on model application and sensitivity analysis, rather than model development, and includes evaluation of all relevant processes, without focussing on any specific model aspect. The results of this study show that SWAN simulations correlated well with observations at the nearshore station in Algoa Bay, both in wave spectral shape and its associated parameters. Dominant processes identified for the field case were depth-induced refraction, bottom friction and directional spreading. This finding agrees with those of previous evaluations of SWAN and previous modelling experience by others. It is shown that high-energy swell is relatively more sensitive to the choices of model setup than wind sea. Based on the simulation results of high-energy swell, it is concluded that the calculation of depth-induced refraction in SWAN seem to contain a degree of inaccuracy. It is also concluded that the findings of this study could be used as a guideline to SWAN modelling studies along the South African south coast. / AFRIKAANSE OPSOMMING: In hierdie studie word die toepassingsmoontlikhede van die numeriese kortgolf model SWAN vir 'n geselekteerde gedeelde van die Suid-Afrikaanse kuslyn beoordeel. Die doel van hierdie studie is om die vlak van akkuraatheid waarmee SWAN prototipe golfspektra en golfparameters (bv. golfhoogte, gemiddelde golfrigting en gemiddelde golfperiode) in die vlakwater kan simuleer te beoordeel, vir 'n Algoabaai gevallestudie. Algoabaai verteenwoordig 'n tipiese diep, beskermde baai aan die Suid-Afrikaanse kuslyn, wat blootgestel is aan hoe-energie deining. Sensitiwiteitstoetse is ook uitgevoer vir verskillende golfprosesse, met die doel om die dominante fisiese prosesse en gepaste modelopstelling vir die Algoabaai gevallestudie te vind. Nadat die dominante golfprosesse geidentifiseer is, en die toepaslike modelopstelling gevind is, is finale simulasies uitgevoer vir geselekteerde gevalle om die mate van akkuraatheid te bepaal waarmee SWAN prototipe kondisies kan simuleer, deur simulasie resultate met beskikbare veldmetings te vergelyk. Hierdie studie bestaan uit 'n samevatting van die evaluasiewerk verrig op SWAN deur andere, 'n samevatting van golf-, wind- en stroomtoestande aan die Suid-Afrikaanse kus en numeriese modelsimulasies. Die modelsimulasies, wat die hooffokus van hierdie studie is, is uitgevoer vir 'n seleksie van beskikbare diepsee golftoestande (in 85 m waterdiepte) uit die Algoabaai gevallestudie en is vergelyk met beskikbare vlakwater metings (in 17 m waterdiepte). Omgewingstoestande van golwe, wind en seestrome is ingesluit in hierdie simulasies. Die studie fokus op modeltoepassing en sensitiwiteits-analise, eerder as modelontwikkeling, en behels die beoordeeling van alle toepaslike modelprosesse, sonder om te fokus op enige spesifieke model aspek. Die resultate van hierdie studie toon aan dat die SWAN simulasies goed korrileer met vlakwater meetings in Algoabaai, vir beide golfspektraalvorm en verwante golfparameters. Bodemrefraksie, bodemwrywing en rigtingsspreiding is geidentifiseer as dominante modelprosesse. Hierdie resultaat kom ooreen met bevindings van vroeere beoordeling van SWAN en modelleer-ervaring deur andere. Dit word aangetoon dat hoe-energie deining relatief meer sensitief is vir modelopstelling as wind-see. Gebasseer op resultate van simulasie met hoe-energie deining, word die gevolgtrekking gemaak dat die berekening van bodemrefraksie in SWAN 'n mate van onakkuraatheid toon. Die gevolgtrekking word ook gemaak dat die resultate van hierdie studie as riglyn gebruik kan word vir modelleerwerk met SWAN aan die Suid-Afrikaanse suidkus.

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-12-21T11:51:34Z No. of bitstreams: 0 / Made available in DSpace on 2016-12-21T11:51:34Z (GMT). No. of bitstreams: 0 / Os radionuclídeos naturais das séries radioativas do 238U e do 232Th têm sido aplicados com sucesso como traçadores de processos ambientais atuais e mudanças climáticas. O 210Pb (meia-vida de 22,2 anos) é empregado na técnica de datação geocronológica de testemunhos sedimentares dos últimos 100-150 anos e na determinação de taxa de sedimentação. As concentrações dos isótopos 226Ra e 228Ra (meia-vida de 1.600 anos e 5,75 anos, respectivamente) auxiliam no cálculo das atividades de 210Pb em excesso no sedimento e auxiliam na identificação de processos marinhos importantes, como, por exemplo, a intrusão de água subterrânea. Neste trabalho foram quantificadas as concentrações de atividade de 226Ra, 228Ra e 210Pb em quatro testemunhos marinhos curtos coletados desde a plataforma continental até o talude superior do Atlântico Sudoeste. A partir dos resultados obtidos, as taxas de sedimentação em cada local e as idades de cada fatia de sedimento foram determinadas pelo método de datação geocronológica com 210Pb. As amostras sedimentares sofreram digestão total ácida em microondas. A separação radioquímica sequencial de 226Ra, 228Ra e 210Pb foi realizada com a obtenção dos precipitados de Ba(Ra)SO4 e PbCrO4. As medidas &alpha; total do 226Ra e &beta; total do 228Ra e do 210Pb a partir dos precipitados foram feitas em um detector proporcional de fluxo gasoso de baixa radiação de fundo. Com relação aos testemunhos analisados, as concentrações de atividade dos radionuclídeos variaram de 14 Bq.kg-1 a 154 Bq.kg-1 para o 226Ra; de 17 Bq.kg-1 a 45 Bq.kg-1 para o 228Ra; de 20 Bq.kg-1 a 2.073 Bq.kg-1 para o 210Pb. Valores altos de 210Pb foram encontrados no topo de todos os perfis sedimentares, proveniente principalmente da deposição atmosférica. Os dados coletados neste trabalho estão na mesma faixa de grandeza de outros relacionados a medições de 226Ra, 228Ra, 210Pb em áreas não contaminadas do Oceano Atlântico Sudoeste. As taxas de sedimentação diminuíram com o aumento da profundidade de coluna dágua, cujos valores variaram de 0,049 cm.ano-1 a 0,40 cm.ano-1. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Aufgrund der komplexen Strahler-Werkstoff-Wechselwirkung beim Erwärmen von Kunststoffen mit Infrarotstrahlung ist in vielen Infrarotschweißprozessen eine Rauchentwicklung zu beobachten. Diese tritt oftmals bei ruß- und/oder glasfasergefüllten Kunststoffen auf und resultiert in einem thermisch-oxidativen Werkstoffabbau, welcher zu einer Abnahme der mechanischen und thermischen Verbindungseigenschaften führt. Die Rauchbildung kann zudem lufttechnische Maßnahmen, wie Absaugeinrichtungen, an der Schweißmaschine erforderlich machen. Der Problematik der Rauchentwicklung beim Infrarotschweißen (IR-Schweißen) von Kunststoffen wird derzeit mit zeitintensiven, empirischen Voruntersuchungen zur Parameterfindung entgegengewirkt. Ziel ist es Strahlerabstands-Erwärmzeit-Kombinationen zu finden, die zu einer ausreichenden Schmelzeerzeugung bei möglichst niedriger thermisch-oxidativer Werkstoffbelastung führen. Ein Ansatz zur Reduzierung des Vorversuchsaufwandes ist die Temperaturmessung der bestrahlten Substratoberfläche, welche unterhalb der Zersetzungstemperatur des bestrahlten Kunststoffs liegen sollte. Derzeitig können jedoch nur ergänzende thermographische und pyrometrische Temperaturmesssysteme eingesetzt werden, welche eine vergleichende Messung der Prozesstemperaturen beim IR-Schweißen ermöglichen und die Prozessstabilität des IR-Schweißprozesses in einem festgelegten Prozessfenster gewährleisten. Eine Messung der tatsächlichen Kunststofftemperaturen ist mit diesen Systemen nicht möglich. Aktuell hat eine Änderung der zu schweißenden Kunststoffe, der Füllstoffe (z. B. Glasfasern) oder ein Schwanken der Füll-und Verstärkungsstoffgehalte der Kunststoffe zur Folge, dass neue Voruntersuchungen zur Prozessparameterfindung des IR-Schweißprozesses notwendig werden. Aufgrund dessen entwickeln die Professur Kunststoffe an der Technischen Universität Chemnitz und die Firma Eugen Riexinger aus Bad Liebenzell eine Temperaturmessmethodik zur Bestimmung der tatsächlich auftretenden Substrattemperaturen während der Infraroterwärmung von Kunststoffen. Die Methodik soll eine IR-Erwärmung von Kunststoffen auf eine kunststoffabhängige Soll-Temperatur ermöglichen und verhindert so die Rauchbildung während der IR-Erwärmung und damit die thermisch-oxidative Werkstoffschädigung. Der Beitrag beschreibt die aktuell auftretenden Herausforderungen beim IR-Schweißen von Kunststoffen, die gewählte Herangehensweise an die Entwicklung der Temperaturmessmethodik zur Bestimmung der tatsächlichen Substrattemperatur sowie die Ergebnisse des Entwicklungsprozesses.

Der Vortrag zeigt die Komplexität der Wechselwirkungen zwischen Infrarotstrahler und Werkstoff beim Infrarotschweißen von Kunststoffen auf. Hierfür werden die Haupteinflüsse auf die Strahler-Werkstoff-Wechselwirkungen beschrieben. Diese sind das Emissionsverhalten des Infrarotstrahlers und das Absorptionsverhalten des Kunststoffs. Der Einfluss der Infrarotstrahlerart (Quarzglasstrahler, Metallfolienstrahler) und von Füllstoffen (Ruß, Glasfasern) im Kunststoff wird näher betrachtet. Zudem enthält der Vortrag eine Empfehlung für die Vorgehensweise beim Infrarotschweißen von Kunststoffen, die Vor- und Nachteile des Fügeverfahrens und einen Einblick in aktuelle Forschungsaktivitäten auf dem Gebiet des Infrarotschweißens von Kunststoffen.

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