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Rehabilitační péče jako prevence poruch hybnosti u impingement syndromu / Physiotherapy and It's Role in Impingement SyndromeMašek, Jiří January 2010 (has links)
Subacromial impingement syndrome is among the most frequent cases of shoulder pain and dysfunction in adults. It's reffered to as shoulder pain is third only to headache and back pain in freqency seen in the practitioner's office. It's known, SIS is a heterogenous entity, which can be caused by a lot of ethiological factors. These factors can have bad influence of architecture of the subacromial space. The tendons of the rotator cuff are passing trough this space and so that structures are most often affected by degenerative disorders. Clinical history and physical examination play a key role in diagnostics. Provocative manoeuvres (Neer's sign, Hawkin's test, Yocum manoeuvre) seem to be useful for identifying impingement syndrome. If there is a reasonable doubt in diagnostics we can use imaging methods. We should start with the minimally invasive and the most economic method. Commonly used course of action include x-ray, ultrasound and MRI. Well-timed and the most accurate diagnostics enable us to start suitable treatment. The treatment commonly starts with pain-relief drugs (NSAID, subacromial injection of mixture of corticosteroid and local anestethic). The combination of physiotherapy and manual therapy seems to be an effective treatment method. This therapeutic combination is good for improving function...
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Pensée et action : le grand savant El Hadji Malick Sy /Mbaye, El Hadji Ravane. January 2003 (has links)
Th. doct.--Lett.--Paris-Sorbonne, 1993. / Texte de deux oeuvres de Malick Sy en arabe et trad. française en regard. Bibliogr. et index à la fin de chaque vol.
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Børje Mogensen soffa : Uträkning av dunplymåer och dess planeringJohansson, Kristina January 2016 (has links)
Uppsatsen handlar om renovering på en soffa modell "2209 sofa" designad av Børje Mogensen. Där fokus ligger på hur dunplymåer växer fram från planering till färdig produkt. Soffans övriga renovering är med ytligt i dokumentet, för att kunna ge en överblick. Denna undersökning behövs då den befintliga litteraturens beskrivningar om dunplymåer är ganska ytliga. Det som saknas i de befintliga beskrivningarna om dunplymåer är hur du kan blanda ihop dun och bollfibrer för att få en mer lättskött plymå. Hur mycket dun respektive bollfibrer det går att ha i plymån för att den ska bli bra stoppningsmässigt. De har inte heller med någonting om hur du ska få en plymå ligga bra emot kanter på stommen. Alltså hur man ska tänka/göra med avskärningar och tillägg. Resultaten visar att bollfibern fyller sin funktion ihop med dunet och förenklar underhållet med dunplymån. Eftersom att dunplymån blev bra i stoppning så är en kubikuträkning gjord på hur mycket dun/bollfiber du behöver per kubikdecimeter (dm3). Bågtilläggen/avskärningarna blev lagom på dunplymån, de fyller ut sina funktioner och täcker alla eventuella hål som lätt kan bli om du undviker dem. Den här uppsatsen handlar alltså om att ge svar på de frågor runt dunplymåer där information sedan innan saknas och förenkla planeringen av dunplymåer i framtiden
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Die regsaanspreeklikheid van 'n vakbond teenoor sy lede / Charles Henry John HiggsHiggs, Charles Henry John January 2013 (has links)
The Constitution of the Republic of South Africa6 (hereinafter the Constitution) gives everyone the right to fair labour practices.7 The Labour Relations Act8 (hereinafter the LRA) regulates the relationship between employers and employees as well as the relationship between employers and trade unions. These labour relations are quite extensively regulated by statutory measures. The same can unfortunately not be said about the relationship between a trade union and its members. Because a trade union is a legal entity, a trade union is controlled and managed by certain functionaries like any body corporate. The management structures of the trade union are defined in the trade union’s constitution. A trade union can not perform any legal functions which are not provided for in the trade union’s constitution. 9 The trade union’s constitution states the nature of the relationship between the union and its members.10
Workers join trade unions in order to protect themselves and their rights in the workplace. An expectation is therefore cultivated by the members that the trade union, through its representative power and mandate to act on behalf of the members, will do so in the best interest of the members. The disruption of the relationship can have negative implications for the trade union. In this study, relevant case law will be sited to explain the contents of the legal responsibility of a trade union to its members. The specific focus of the study is the legal responsibility of a trade union if its members would suffer pecuniary loss or harm as a result of the trade union’s actions.
The purpose of this study is to discuss the regulation of the relationship between a trade union and its members in South Africa and to find a solution for the fragmented regulation or non-regulation thereof. The authority that a member grants to a trade union, mostly in the form of a contract, involves the expression of the will of the members that the trade union has the necessary power to perform judicial acts on its behalf. The discussion is limited to the actual authorization originated by a contract of mandate between a trade union and its members. In terms of the common law’s contract of mandate a representative is obliged to perform his orders with care and diligence, convey information, to act in good faith and to account for his actions. There are no statutory measures that regulate the nature of the legal relationship between a trade union and its members provided for in the trade union’s constitution. This study discusses the regulatory challenges that the regulation of the relationship between a trade union and its members in South Africa are facing, and some recommendations are made with regards to the possible application of existing legislation and the common law contract of mandate. / LLM (Labour Law), North-West University, Potchefstroom Campus, 2014
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Die regsaanspreeklikheid van 'n vakbond teenoor sy lede / Charles Henry John HiggsHiggs, Charles Henry John January 2013 (has links)
The Constitution of the Republic of South Africa6 (hereinafter the Constitution) gives everyone the right to fair labour practices.7 The Labour Relations Act8 (hereinafter the LRA) regulates the relationship between employers and employees as well as the relationship between employers and trade unions. These labour relations are quite extensively regulated by statutory measures. The same can unfortunately not be said about the relationship between a trade union and its members. Because a trade union is a legal entity, a trade union is controlled and managed by certain functionaries like any body corporate. The management structures of the trade union are defined in the trade union’s constitution. A trade union can not perform any legal functions which are not provided for in the trade union’s constitution. 9 The trade union’s constitution states the nature of the relationship between the union and its members.10
Workers join trade unions in order to protect themselves and their rights in the workplace. An expectation is therefore cultivated by the members that the trade union, through its representative power and mandate to act on behalf of the members, will do so in the best interest of the members. The disruption of the relationship can have negative implications for the trade union. In this study, relevant case law will be sited to explain the contents of the legal responsibility of a trade union to its members. The specific focus of the study is the legal responsibility of a trade union if its members would suffer pecuniary loss or harm as a result of the trade union’s actions.
The purpose of this study is to discuss the regulation of the relationship between a trade union and its members in South Africa and to find a solution for the fragmented regulation or non-regulation thereof. The authority that a member grants to a trade union, mostly in the form of a contract, involves the expression of the will of the members that the trade union has the necessary power to perform judicial acts on its behalf. The discussion is limited to the actual authorization originated by a contract of mandate between a trade union and its members. In terms of the common law’s contract of mandate a representative is obliged to perform his orders with care and diligence, convey information, to act in good faith and to account for his actions. There are no statutory measures that regulate the nature of the legal relationship between a trade union and its members provided for in the trade union’s constitution. This study discusses the regulatory challenges that the regulation of the relationship between a trade union and its members in South Africa are facing, and some recommendations are made with regards to the possible application of existing legislation and the common law contract of mandate. / LLM (Labour Law), North-West University, Potchefstroom Campus, 2014
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The Development of an Integrated Process Operation Management Systemypower@bigpond.com.au, Yvonne Power January 2004 (has links)
This project details the development of a new framework known as the Coordinated Knowledge Management method to enable complete task integration of all low and midlevel tasks for process industries. The framework overcomes past problems of task integration, which made it impossible to have a fully integrated system and with integration being limited to data acquisition, regulatory control and occasionally supervisory control.
The main component of the project includes the use of hierarchically structured timed place Petri nets, which have not previously been used for integrating tasks in intelligent process operations management. Tasks which have been integrated include all low-level tasks such as data acquisition, regulatory control and data reconciliation, and all mid-level tasks including supervisory control and most significantly the integration of process monitoring fault detection and diagnosis.
The Coordinated Knowledge Management method makes use of hierarchical timed place Petri nets to (i) coordinate tasks, (ii) monitor the system, (iii) activate tasks, (iv) send requests for data updates and (iv) receive notice when tasks are complete. Visualization of the state of the system is achieved through the moving tokens in the Petri net. The integration Petri nets are generic enough to be applied to any plant for integration using existing modules thus allowing the integration of different tasks, which use different problem solving methodologies.
Integrating tasks into an intelligent architecture has been difficult to achieve in the past since the developed framework must be able to take into account information flow and timing in a continuously changing environment. In this thesis Petri nets have been applied to continuous process operations rather than to batch processes as in the past. In a continuous process, raw materials are fed and products are delivered continuously at known flow-rates and the plant is generally operated at steady state (Gu and Bahri, 2002).
However, even in a continuous process, data is received from the distributed control system (DCS) at discrete time intervals. By transforming this data into process events, a Petri net can be used for overseeing process operations. The use of hierarchical Petri nets as the coordination mechanism introduces inherent hierarchy without the rigidity of previous methods. Petri nets are used to model the conditions and events occurring within the system and modules. This enables the development of a self-monitoring system, which takes into account information flow and timing in a continuously changing environment. Another major obstacle to integration of tasks in the past has been the presence of faults in the process. The project included the integration of fault detection and diagnosis a component not integrated into current systems but which is necessary to prevent abnormal plant operation. A novel two-step supervisory fault detection and diagnosis framework was developed and tested for the detection and diagnosis of faults in large-scale systems, using condition-event nets for fault detection and Radial Basis Function neural networks for fault diagnosis. This fault detection and diagnosis methodology detects and diagnoses faults in the early stages of fault occurrence, before fault symptoms propagate throughout the plant.
The Coordinated Knowledge Management method and the newly developed fault diagnosis module were developed in G21 and applied and tested on the Separation and Heating sections of the Pilot plant for the Bayer process at the School of Engineering Science, Murdoch University. Testing indicated that the use of an intelligent system comprising of Petri nets for integration of tasks results in improved plant performance and makes the plant easier to monitor increasing profits. The fault detection and diagnosis module was found to be useful in detecting faults very early on and diagnosing the exact location of faults, which would otherwise prove to be difficult to detect. This would also increase plant safety, reduce wastage and improve environmental considerations of the plant.
References
Gensym Corporation (1999). G2 Reference Manual (Version 5.0), Cambridge, MA. Gu, T. and P. Bahri (2002). A Survey of Petri Net Applications in Batch Processes, Computers in Industry, 47 (1), p. 99 111.
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Efeitos da quantidade de alimento larval sobre a determinação de castas da abelha sem ferrão Scaptotrigona aff. depilis (Moure, 1942) (Hymenoptera, Apidae, Meliponini) - uma análise morfométrica, de expressão gênica e de títul / The role of the quantity of larval diet in caste determination of the stingless bee Scaptotrigona aff. depilis (Moure, 1942) (Hymenoptera, Apidae, Meliponini) a morphometric, gene expression e hormone titer analysisGisele de Carvalho Pinto Cabral 23 November 2009 (has links)
Neste estudo, foi investigado o efeito da dieta larval no desenvolvimento de características morfológicas casta-específicas e na expressão de alguns genes durante o desenvolvimento da abelha sem ferrão Scaptotrigona aff. depilis . Nesta espécie, as castas femininas são determinadas pela quantidade de alimento consumida durante o desenvolvimento larval. Grupos experimentais larvas criadas in vitro foram feitos com duas quantidades diferentes de alimento larval, obtido de favos recém provisionados nesta espécie. As larvas do primeiro grupo receberam 32l de alimento larval, correspondente a quantidade média de alimento recebida por larvas de operárias naturalmente, já as larvas do segundo grupo receberam 130l, correspondente a quantidade média encontrada naturalmente em células reais. Todas as larvas criadas com 130l de alimento larval se desenvolveram em rainhas, como esperado; da mesma forma, a maioria das larvas criadas com 32l se desenvolveram em operárias. Interessantemente, porém, algumas larvas deste grupo se desenvolveram em rainhas miniaturas, sugerindo que outros fatores, além do trófico, estejam envolvidos na determinação de castas em S. aff. depilis. Subsequentemente, analisamos os títulos de hormônio juvenil (HJ) na hemolinfa por radioimunoensaio durante quatro estágios do último instar larval e encontramos que as larvas do grupo de 130l de dieta apresentaram maiores títulos no estágio defecante (LD) (p=0,034, t-test), se comparado com as larvas do grupo de 32l. Os níveis de expressão de determinados genes que foram previamente descritos em outras espécies como expressos preferencialmente em rainhas. Um destes genes, dnmt-3, codifica a DNA metiltransferase envolvida na metilação do DNA. Para este gene, encontramos maiores níveis de transcritos nas larvas alimentadas como rainhas (130l) nos estágios LPD e LD (p=0,029, Mann-Whitney), do que as larvas que receberam 32l. Analisamos também dois genes envolvidos no metabolismo do HJ, e para um deles, jheh, codificador de uma epóxido-hidrolase do hormônio juvenil, não encontramos diferença nos níveis de mRNA entre larvas de rainhas e operárias. Para jhe, o qual codifica a esterase do hormônio juvenil, encontramos maiores níveis de transcritos no estágio LD nas larvas criadas com 130l de alimento. Isso indica que a expressão de jhe pode ser induzida pelo aumento dos títulos de HJ neste estágio. Os dois genes, hmgr e mfe, envolvidos no passo inicial e final da síntese do HJ, respectivamente, o primeiro mostrou uma pequena variação nos níveis de expressão, sendo que a expressão de mfe foi menor nas larvas criadas com 32l de alimento larval e foi encontrado um pico de expressão no estágio LPD nas larvas alimentadas com 130l. O produto desse gene, metilfarnesoato epoxidase, está envolvido no passo limitante da síntese de HJ em Apis mellifera. Dois outros genes analisados foram o homólogo ao EcR, codificador do receptor de ecdisona e o usp, codificador do potencial receptor do HJ. Seus níveis de expressões foram maiores nos estágios LPD e LD, respectivamente, nas larvas alimentadas com 130l de alimento e os níveis de EcR se correlacionaram com o perfil dos títulos de ecdisona e os de usp com os títulos de HJ, publicados para esta espécie. Não houve diferença nos níveis de expressão dos genes selecionados que pudessem relacionar ou permitir distinguir as rainhas miniaturas das operárias durante os estágios do desenvolvimento estudados. Uma análise morfométrica de adultos faratos indica claramente que as rainhas miniaturas são rainhas autênticas. / In this work we investigated the role played by the larval diet in the development of caste-specific morphological traits and in the expression of candidate genes during the development of the stingless bees, Scaptotrigona aff. depilis. In this species, the female castes are determinate by the amount of food consume during larval development. Experimental groups of larvae were reared in vitro on two different quantities of larval food obtained from newly provisioned brood cells of this species. Larvae of the first group received 32l of larval food, corresponding to the quantity usually received by the workers larva, whereas larvae of the second group received 130l, corresponding to the quantity normally deposited in queen cells. All larvae reared on 130l of larval food developed into queens, as expected, and similarly, most of the larvae reared on 32l developed into workers. Interestingly, however, some larvae of this group developed into miniature queens, suggesting that factors additional to the trophic ones may be involved in caste determination in S. aff. depilis. We subsequently analyzed the hemolymph juvenile hormone (JH) titers by radioimmunoassay during four stages of the last larval instar and we found that larvae of the 130l diet group had higher JH titer in the defecating stange (LD) (p=0,034, t-test) than larvae of the 32l diet group. Next we analyzed the expression levels of set of candidate genes that had previously been described as preferentially expressed in queens of others bee species. One of these genes dnmt-3, encodes DNA methyltransferase involved in DNA methylation. For this gene we found higher transcripts levels in prospective queens during the final larval stage (both in pre-defecating larvae LPD and defecating larvae- LD) (p=0,029, Mann-Whitney). We also analyzed two genes involved in JH metabolism, and for one of them jheh, encoding a juvenile hormone epoxide hydrolase, we did not find any differences in mRNA levels for queens and workers larvae. For jhe, which codes juvenile hormone esterase we found higher transcript levels in the LD stage in larvae reared on 130l of larval food. This indicates that jhe expression may be induced by an elevated JH titer during this stage. For two genes, hmgr and mfe, involved in an initial and a final step of JH synthesis, respectively, the first one showed little variation in expression levels, whereas mfe expression was lower in larvae reared on 32l of larval food and we found an expression peak in the LPD stage (p=0,029, Mann-Whitney) of larvae reared on 130l larval food. The product of this gene, a methylfarnesoate epoxidase, has been shown to be involved in a rate-limiting step of JH sunthesis in the honey bee, Apis mellifera. The other two genes analyzed were the EcR homolog encoding an ecdysone receptor and usp coding for potencial JH receptor. Their expressions were higher during LPD (p=0,006, t-test) stages and LD (p=0,026, t-test), respectively, in larvae fed with 130l of food and the levels of transcripts of EcR correlated with changes in the ecdysone titer and usp with the JH titer published for this species. We did not find differences in expressions levels for any of these candidate genes that could related to and allow to distinguish between prospective miniature queens and workers in these stages. A morphometric analysis of pharate adults, however, clearly demonstrated that the miniature queens are authentic queens.
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Efeitos da quantidade de alimento larval sobre a determinação de castas da abelha sem ferrão Scaptotrigona aff. depilis (Moure, 1942) (Hymenoptera, Apidae, Meliponini) - uma análise morfométrica, de expressão gênica e de títul / The role of the quantity of larval diet in caste determination of the stingless bee Scaptotrigona aff. depilis (Moure, 1942) (Hymenoptera, Apidae, Meliponini) a morphometric, gene expression e hormone titer analysisCabral, Gisele de Carvalho Pinto 23 November 2009 (has links)
Neste estudo, foi investigado o efeito da dieta larval no desenvolvimento de características morfológicas casta-específicas e na expressão de alguns genes durante o desenvolvimento da abelha sem ferrão Scaptotrigona aff. depilis . Nesta espécie, as castas femininas são determinadas pela quantidade de alimento consumida durante o desenvolvimento larval. Grupos experimentais larvas criadas in vitro foram feitos com duas quantidades diferentes de alimento larval, obtido de favos recém provisionados nesta espécie. As larvas do primeiro grupo receberam 32l de alimento larval, correspondente a quantidade média de alimento recebida por larvas de operárias naturalmente, já as larvas do segundo grupo receberam 130l, correspondente a quantidade média encontrada naturalmente em células reais. Todas as larvas criadas com 130l de alimento larval se desenvolveram em rainhas, como esperado; da mesma forma, a maioria das larvas criadas com 32l se desenvolveram em operárias. Interessantemente, porém, algumas larvas deste grupo se desenvolveram em rainhas miniaturas, sugerindo que outros fatores, além do trófico, estejam envolvidos na determinação de castas em S. aff. depilis. Subsequentemente, analisamos os títulos de hormônio juvenil (HJ) na hemolinfa por radioimunoensaio durante quatro estágios do último instar larval e encontramos que as larvas do grupo de 130l de dieta apresentaram maiores títulos no estágio defecante (LD) (p=0,034, t-test), se comparado com as larvas do grupo de 32l. Os níveis de expressão de determinados genes que foram previamente descritos em outras espécies como expressos preferencialmente em rainhas. Um destes genes, dnmt-3, codifica a DNA metiltransferase envolvida na metilação do DNA. Para este gene, encontramos maiores níveis de transcritos nas larvas alimentadas como rainhas (130l) nos estágios LPD e LD (p=0,029, Mann-Whitney), do que as larvas que receberam 32l. Analisamos também dois genes envolvidos no metabolismo do HJ, e para um deles, jheh, codificador de uma epóxido-hidrolase do hormônio juvenil, não encontramos diferença nos níveis de mRNA entre larvas de rainhas e operárias. Para jhe, o qual codifica a esterase do hormônio juvenil, encontramos maiores níveis de transcritos no estágio LD nas larvas criadas com 130l de alimento. Isso indica que a expressão de jhe pode ser induzida pelo aumento dos títulos de HJ neste estágio. Os dois genes, hmgr e mfe, envolvidos no passo inicial e final da síntese do HJ, respectivamente, o primeiro mostrou uma pequena variação nos níveis de expressão, sendo que a expressão de mfe foi menor nas larvas criadas com 32l de alimento larval e foi encontrado um pico de expressão no estágio LPD nas larvas alimentadas com 130l. O produto desse gene, metilfarnesoato epoxidase, está envolvido no passo limitante da síntese de HJ em Apis mellifera. Dois outros genes analisados foram o homólogo ao EcR, codificador do receptor de ecdisona e o usp, codificador do potencial receptor do HJ. Seus níveis de expressões foram maiores nos estágios LPD e LD, respectivamente, nas larvas alimentadas com 130l de alimento e os níveis de EcR se correlacionaram com o perfil dos títulos de ecdisona e os de usp com os títulos de HJ, publicados para esta espécie. Não houve diferença nos níveis de expressão dos genes selecionados que pudessem relacionar ou permitir distinguir as rainhas miniaturas das operárias durante os estágios do desenvolvimento estudados. Uma análise morfométrica de adultos faratos indica claramente que as rainhas miniaturas são rainhas autênticas. / In this work we investigated the role played by the larval diet in the development of caste-specific morphological traits and in the expression of candidate genes during the development of the stingless bees, Scaptotrigona aff. depilis. In this species, the female castes are determinate by the amount of food consume during larval development. Experimental groups of larvae were reared in vitro on two different quantities of larval food obtained from newly provisioned brood cells of this species. Larvae of the first group received 32l of larval food, corresponding to the quantity usually received by the workers larva, whereas larvae of the second group received 130l, corresponding to the quantity normally deposited in queen cells. All larvae reared on 130l of larval food developed into queens, as expected, and similarly, most of the larvae reared on 32l developed into workers. Interestingly, however, some larvae of this group developed into miniature queens, suggesting that factors additional to the trophic ones may be involved in caste determination in S. aff. depilis. We subsequently analyzed the hemolymph juvenile hormone (JH) titers by radioimmunoassay during four stages of the last larval instar and we found that larvae of the 130l diet group had higher JH titer in the defecating stange (LD) (p=0,034, t-test) than larvae of the 32l diet group. Next we analyzed the expression levels of set of candidate genes that had previously been described as preferentially expressed in queens of others bee species. One of these genes dnmt-3, encodes DNA methyltransferase involved in DNA methylation. For this gene we found higher transcripts levels in prospective queens during the final larval stage (both in pre-defecating larvae LPD and defecating larvae- LD) (p=0,029, Mann-Whitney). We also analyzed two genes involved in JH metabolism, and for one of them jheh, encoding a juvenile hormone epoxide hydrolase, we did not find any differences in mRNA levels for queens and workers larvae. For jhe, which codes juvenile hormone esterase we found higher transcript levels in the LD stage in larvae reared on 130l of larval food. This indicates that jhe expression may be induced by an elevated JH titer during this stage. For two genes, hmgr and mfe, involved in an initial and a final step of JH synthesis, respectively, the first one showed little variation in expression levels, whereas mfe expression was lower in larvae reared on 32l of larval food and we found an expression peak in the LPD stage (p=0,029, Mann-Whitney) of larvae reared on 130l larval food. The product of this gene, a methylfarnesoate epoxidase, has been shown to be involved in a rate-limiting step of JH sunthesis in the honey bee, Apis mellifera. The other two genes analyzed were the EcR homolog encoding an ecdysone receptor and usp coding for potencial JH receptor. Their expressions were higher during LPD (p=0,006, t-test) stages and LD (p=0,026, t-test), respectively, in larvae fed with 130l of food and the levels of transcripts of EcR correlated with changes in the ecdysone titer and usp with the JH titer published for this species. We did not find differences in expressions levels for any of these candidate genes that could related to and allow to distinguish between prospective miniature queens and workers in these stages. A morphometric analysis of pharate adults, however, clearly demonstrated that the miniature queens are authentic queens.
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Etude de l'Influence de la vapeur d'eau sur l'oxydation à haute température d'un alliage chromino-formeur à base de nickelRolland, Raphaël 14 March 2012 (has links) (PDF)
Ce travail s'inscrit dans un cadre de recherche qui a pour objectif essentiel l'étude de l'influence de la vapeur d'eau sur l'oxydation à haute température d'un alliage formeur de Cr2O3 à base de nickel. L'alliage étudié pour cette étude est le SY 625. L'originalité de cette étude repose sur l'utilisation d'un montage expérimental, mis en oeuvre au laboratoire. Ce montage appelé " montage vapeur d'eau " permet de réaliser l'oxydation du SY 625 à haute température (900-1100°C) en présence de vapeur d'eau (7,5 et 33% de vapeur d'eau) avec différents gaz vecteurs (oxygène, air, argon et azote) en conditions isotherme ou cyclique. Les résultats cinétiques obtenus sous air, ne montrent pas de différences notables que l'oxydation soit réalisée en conditions sèche ou humide (quelque soit le taux de vapeur d'eau). Les résultats n'ont pas montré de breakaway pour les durées d'oxydation allant jusqu'à 48 heures. Ceci est attribué au fait qu'il n'y a pas formation d'oxydes de fer sachant que l'alliage contient seulement 0,23% en masse de fer. Les résultats de DRX montrent la formation des mêmes phases quel-que-soit le gaz vecteur utilisé (en atmosphère sèche ou humide). A 900 et 1000°C, l'oxyde Cr2O3 est détecté ainsi que deux composés intermétalliques : Ni3Mo et NbNi4. En revanche à 1100°C, l'oxyde Cr2O3 est toujours présent mais les composés intermétalliques sont oxydés pour donner un oxyde mixte CrNbO4. L'oxydation du molybdène au dessus de 1000°C conduit à la formation de MoO3 qui est un oxyde volatil. Les analyses morphologiques, ont montré la présence de couches de chromine plus plastiques avec une porosité répartie sur toute l'épaisseur de la couche pour les essais réalisés en présence de vapeur d'eau. Les couches d'oxyde sont alors plus adhérentes. Ceci a été confirmé par des essais d'oxydation en conditions cycliques, qui ont montré notamment à 1100°C, une meilleure tenue mécanique de la couche d'oxyde en présence de vapeur d'eau. Les tests d'oxydation en présence d'un marquage à l'or a aussi permis de mettre en évidence un mécanisme d'oxydation mixte pour les oxydations réalisées en atmosphères riche en oxygène que l'on soit sous atmosphère sèche ou humide. En revanche, le marquage à l'or a montré la présence d'un mécanisme d'oxydation interne pour les atmosphères pauvres en oxygène, avec des couches d'oxydes présentant une adhérence parfaite. Le fait d'ajouter de la vapeur d'eau à ces atmosphères pauvres en oxygène, entraine la réapparition d'un mécanisme de diffusion mixte.
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Simulation of a building heating, ventilating and air-conditioning systemBotha, C P 03 July 2006 (has links)
Simulation is one of the oldest and also among the most important tools available to engineers. In the building Heating, Ventilating and Air-Conditioning (HVAC) community the availability and/or functionality of simulation tools is limited and it is difficult to determine whether the simulation models accurately represent reality. The purpose of this study was to accurately verify one such a simulation model and then to extend the study to two unique applications. Comprehensive structural, comfort and energy audits were performed to construct a suitable simulation model with the aid of the control simulation package: QUICK Control. The model was then verified against measured building data to ensure an accurate representation of the actual dynamic building response. For the first application various control retrofits were evaluated and the highest potential for energy saving was found. Thereafter the model was implemented to investigate the change in indoor air conditions due to failure of HVAC equipment. Heating, ventilating and air-conditioning in buildings consume a significant portion of the available electrical energy in South Africa. Of this energy up to 30% can be saved by improving the HVAC systems currently installed in the buildings. This could result in savings of up to R400 million. For the building used in this study it was found that up to 66% of the HVAC system’s electrical energy consumption could be saved with a payback period of only 9 months. These savings could be achieved by implementing a setback control strategy with an improved time management procedure. Predicting the impact of failing equipment is a difficult task because of the integrated dynamic effect every HVAC component has on the next. With the aid of a comprehensive integrated simulation model the implications of failing can be determined and necessary assessments and precautions can be taken. The results of this study showed that the air-conditioning system under investigation was approximately 100% over designed. Failure of up to 50% was allowable in the cooling equipment before any noticeable impact could be observed in the indoor climate. With further failure the required comfort conditions could not be sustained. <p The substantial savings calculation and possibility of predicting climate deterioration would not have been possible without the aid of a comprehensive simulation package and model. This study clearly highlights the worth of integrated simulation. / Dissertation (MSc (Mechanical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted
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