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Étude anatomique des réseaux neuronaux impliqués dans la régulation du sommeil paradoxal chez le rat. / Anatomic study of the neuronal networks implicated in the paradoxical regulation in ratsSapin, Émilie 07 May 2009 (has links)
L’objectif de notre étude est d’améliorer la connaissance des réseaux neuronaux responsables de la régulation du sommeil paradoxal (SP). Dans ce but, nous avons combiné des techniques de polysomnographie, de neuroanatomie fonctionnelle, de pharmacologie et de traçage de voies nerveuses. Nous avons ainsi mis en évidence une population de neurones GABAergiques à la jonction entre la substance grise périaqueductale ventrolatérale et la partie dorsale du noyau profond du mésencéphale (vlPAG/dDpMe), capable de bloquer l’entrée en SP. Nous avons également démontré l’existence de nombreuses populations de neurones GABAergiques pontiques activés au cours du SP. De plus, nos travaux ont révélé la présence de nombreux neurones GABAergiques, dont les neurones à MCH, actifs en SP dans plusieurs régions hypothalamiques. Enfin, nous avons établi une cartographie des neurones à MCH et à Hcrt envoyant des projections sur les neurones histaminergiques du noyau tubéromammillaire ventral (VTM), promoteurs de l’éveil. L’ensemble de notre travail de thèse a permis d’affiner le modèle des réseaux neuronaux impliqués dans la régulation du SP, particulièrement en confirmant le rôle du GABA dans ces mécanismes de régulation / The aim of our study is to improve the knowledge of the neural networks responsible for paradoxical sleep (PS) regulation. To this end, we combined polysomnographic recordings, functional neuroanatomy, pharmacology and tract-tracing of nervous pathways. We thus highlighted a population of GABAergic neurons at the junction between the ventroleral periaqueductal gray and the dorsal part of the deep mesencephalic nucleus (vlPAG/dDpMe), able to gate PS genesis. We also showed the existence in the pons of several GABAergic neurons populations activated during PS. Moreover, our work revealed the presence of a large number of GABAergic neurons including the MCH neurons, activated in PS in several hypothalamic areas. Finally, we mapped the MCH, Hcrt neurons that send projections to the wake-promoting histaminergic neurons of the ventral tuberomammillary nucleus (VTM). Our thesis work made it possible to refine the model of neural networks involved in PS regulation, particularly by confirming the role of GABA in these mechanisms of regulation.
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Thermal deposition approaches for graphene growth over various substratesPang, Jinbo 07 April 2017 (has links) (PDF)
In the course of the PhD thesis large area homogeneous strictly monolayer graphene films were successfully synthesized with chemical vapor deposition over both Cu and Si (with surface oxide) substrates. These synthetic graphene films were characterized with thorough microscopic and spectrometric tools and also in terms of electrical device performance. Graphene growth with a simple chemo thermal route was also explored for understanding the growth mechanisms.
The formation of homogeneous graphene film over Cu requires a clean substrate. For this reason, a study has been conducted to determine the extent to which various pre-treatments may be used to clean the substrate. Four type of pre-treatments on Cu substrates are investigated, including wiping with organic solvents, etching with ferric chloride solution, annealing in air for oxidation, and air annealing with post hydrogen reduction. Of all the pretreatments, air oxidation with post hydrogen annealing is found to be most efficient at cleaning surface contaminants and thus allowing for the formation of large area homogeneous strictly monolayer graphene film over Cu substrate.
Chemical vapor deposition is the most generally used method for graphene mass production and integration. There is also interest in growing graphene directly from organic molecular adsorbents on a substrate. Few studies exist. These procedures require multiple step reactions, and the graphene quality is limited due to small grain sizes. Therefore, a significantly simple route has been demonstrated. This involves organic solvent molecules adsorbed on a Cu surface, which is then annealed in a hydrogen atmosphere in order to ensure direct formation of graphene on a clean Cu substrate. The influence of temperature, pressure and gas flow rate on the one-step chemo thermal synthesis route has been investigated systematically. The temperature-dependent study provides an insight into the growth kinetics, and supplies thermodynamic information such as the activation energy, Ea, for graphene synthesis from acetone, isopropanol and ethanol. Also, these studies highlight the role of hydrogen radicals for graphene formation. In addition, an improved understanding of the role of hydrogen is also provided in terms of graphene formation from adsorbed organic solvents (e.g., in comparison to conventional thermal chemical vapor deposition).
Graphene synthesis with chemical vapor deposition directly over Si wafer with surface oxide (Si/SiOx ) has proven challenging in terms of large area and uniform layer number. The direct growth of graphene over Si/SiO x substrate becomes attractive because it is free of an undesirable transfer procedure, necessity for synthesis over metal substrate, which causes breakage, contamination and time consumption. To obtain homogeneous graphene growth, a local equilibrium chemical environment has been established with a facile confinement CVD approach, inwhich two Si wafers with their oxide faces in contact to form uniform monolayer graphene. A thorough examination of the material reveals it comprises facetted grains despite initially nucleating as round islands. Upon clustering these grains facet to minimize their energy, which leads to faceting in polygonal forms because the system tends to ideally form hexagons (the lowest energy form). This is much like the hexagonal cells in a beehive honeycomb which require the minimum wax. This process also results in a near minimal total grain boundary length per unit area. This fact, along with the high quality of the resultant graphene is reflected in its electrical performance which is highly comparable with graphene formed over other substrates, including Cu. In addition the graphene growth is self-terminating, which enables the wide parameter window for easy control.
This chemical vapor deposition approach is easily scalable and will make graphene formation directly on Si wafers competitive against that from metal substrates which suffer from transfer. Moreover, this growth path shall be applicable for direct synthesis of other two dimensional materials and their Van der Waals hetero-structures. / Im Zuge dieser Doktorarbeit wurden großflächige und homogene Graphen-Monolagen mittels chemischer Gasphasenabscheidung auf Kupfer- (Cu) und Silizium-(Si) Substraten erfolgreich synthetisiert. Solche monolagigen Graphenschichten wurden mithilfe mikroskopischer und spektrometrischer Methoden gründlich charakterisiert. Außerdem wurde der Wachstumsmechanismus von Graphen anhand eines chemo-thermischen Verfahrens untersucht.
Die Bildung von homogenen Graphenschichten auf Cu erfordert eine sehr saubere Substratoberfläche, weshalb verschiedene Substratvorbehandlungen und dessen Einfluss auf die Substratoberfläche angestellt wurden. Vier Vorbehandlungsarten von Cu-Substraten wurden untersucht: Abwischen mit organischen Lösungsmitteln, Atzen mit Eisen-(III)-Chloridlösung, Wärmebehandlung an Luft zur Erzeugung von Cu-Oxiden und Wärmebehandlung an Luft mit anschließender Wasserstoffreduktion. Von diesen Vorbehandlungen ist die zuletzt genannte Methode für die anschließende Abscheidung einer großflächigen Graphen-Mono-lage am effektivsten.
Die chemische Gasphasenabscheidung ist die am meisten verwendete Methode zur Massenproduktion von Graphen. Es besteht aber auch Interesse an alternativen Methoden, die Graphen direkt aus organischen, auf einem Substrat adsorbierten Molekülen, synthetisieren konnen. Jedoch gibt es derzeit nur wenige Studien zu derartigen alternativen Methoden. Solche Prozessrouten erfordern mehrstufige Reaktionen, welche wiederrum die Qualität der erzeugten Graphenschicht limitieren, da nur kleine Korngrößen erreicht werden konnen. Daher wurde in dieser Arbeit ein deutlich einfacherer Weg entwickelt. Es handelt sich dabei um ein Verfahren, bei dem auf einer Cu-Substratoberfläche adsorbierte, organische Lösungsmittelmoleküle in einer Wasserstoffatmosphäre geglüht werden, um eine direkte Bildung von Graphen auf einem sauberen Cu-Substrat zu gewahrleisten.Der Einfluss von Temperatur, Druck und Gasfluss auf diesen einstufigen chemothermischen Syntheseweg wurde systematisch untersucht. Die temperaturabhängigen Untersuchungen liefern einen Einblick in die Wachstumskinetik und thermodynamische Größen, wie zum Beispiel die Aktivierungsenergie Ea, für die Synthese von Graphen aus Aceton, Isopropanol oder Ethanol. Diese Studien untersuchen außerdem die Rolle von Wasserstoffradikalen auf die Graphensynthese. Weiterhin wurde ein verbessertes Verständnis der Rolle von Wasserstoff auf die Graphen-synthese aus adsorbierten, organischen Lösungsmitteln erlangt (beispielsweise im Vergleich zur konventionellen thermischen Gasphasenabscheidung).
Die direkte Graphensynthese mittels chemischer Gasphasenabscheidung auf Si-Substraten mit einer Oxidschicht (Si/SiOx ) ist extrem anspruchsvoll in Bezug auf die großflächige und einheitliche Abscheidung (Lagenanzahl) von Graphen-Monolagen. Das direkte Wachstum von Graphen auf Si/SiOx -Substrat ist interessant, da es frei von unerwünschten Übertragungsverfahren ist und kein Metall-substrat erfordert, welche die erzeugten Graphenschichten brechen lassen können. Um ein homogenes Graphenwachstum zu erzielen wurde durch den Kontakt zweier Si-Wafer, mit ihren Oxidflachen zueinander zeigend, eine lokale Umgebung im chemischen Gleichgewicht erzeugt. Diese Konfiguration der Si-Wafer ist nötig, um eine einheitliche Graphen-Monolage bilden zu können. Eine gründliche Untersuchung des abgeschiedenen Materials zeigt, dass trotz der anfänglichen Keimbildung von runden Inseln facettierte Körner erzeugt werden. Aufgrund der Bestrebung der Graphenkörner ihre (Oberflächen-) Energie zu minimieren, wird eine Facettierung der Körner in polygonaler Form erzeugt, was darin begründet liegt, dass das System idealerweise eine Anordnung von hexagonal geformten Körnern erzeugen würde (niedrigster Energiezustand). Der Prozess ist vergleichbar mit der sechseckigen Zellstruktur einer Bienenstockwabe, welche ein Minimum an Wachs erfordert. Dieser Prozess führt auch zu einer nahezu minimalen Gesamtkorn-grenzlänge pro Flächeneinheit. Diese Tatsache zusammen mit der hohen Qualität der resultierenden Graphenschicht spiegelt sich auch in dessen elektrischer Leistungsfähigkeit wider, die in hohem Maße mit der auf anderen Substraten gebildeten Graphenschichten (inklusive Cu-Substrate) vergleichbar ist. Darüber hinaus ist das Graphenwachstum selbstabschliessend, wodurch ein großes Parameterfenster für eine einfache und kontrollierte Synthese eröffnet wird.
Dieser Ansatz zur chemischen Gasphasenabscheidung von Graphen auf Si- Substraten ist leicht skalierbar und gegenüber der Abscheidung auf Metallsubstraten konkurrenzfähig, da keine Substratübertragung notig ist. Darüber hinaus ist dieser Prozess auch für die direkte Synthese anderer zweidimensionalen Materialien und deren Van-der-Waals-Heterostrukturen anwendbar.
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Věcněprávní zajištění dluhů v syndikovaném úvěrovém financování / In Rem Security Interests in Syndicated Loan FinanceŽivanský, Jakub January 2015 (has links)
This thesis analyses the legal regime of in rem security interests, in particular pledges and security assignments of rights, in the context of syndicated loan finance. The thesis draws mainly from the Act No. 89/2012 Coll., the Civil Code, and the Act No. 90/2012 Coll., on Commercial Companies and Cooperatives (the Corporations Act), and related legal acts, case law and jurisprudence. In the first chapter, the author describes the main elements of a facilities agreement and the typology of loans. The term syndicated loan is defined as a bank loan provided by two or more creditors, who are not joint and severe creditors among themselves, and which is usually secured by in rem security interests. The second chapter of the thesis introduces the area of securing debts and describes the security and reimbursement functions of security interests. In the third and fourth chapter, the author details the main attributes of in rem security interests. The thesis focuses on the secured party, the security provider and the secured debt whereas emphasis is given on the security agent, whose position can be structured using the institutes of joint and severe creditorship, administration of security, trust and parallel debt. The thesis deals with the ranking of security interests and negative pledges. The author states...
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A proibição do pacto comissório no direito brasileiro / The prohibition of the pacto comissorio in Brazilian law.Haddad, Luís Gustavo 17 June 2013 (has links)
O objetivo central da tese é o de identificar os possíveis fundamentos da proibição do pacto comissório e testá-los mediante contraste com a legislação vigente. Em termos de método, isso é feito como exercício de argumentação jurídica, pautada na ideia de reconstrução racional (MACCORMICK) e na hipótese do legislador racional (FERRAZ JR.). Para alcançar esse objetivo, o trabalho começa por investigar (a) os sentidos dos termos que compõem a locução pacto comissório; e (b) a função e a estrutura da cláusula, que são analisadas sob a premissa teórica da sua licitude. Na sequência, é perquirida a presença da proibição nas legislações estrangeiras e na legislação brasileira. Disso resulta a percepção de que, embora a proibição permaneça largamente presente, há indícios de que ela começa a sofrer erosões, ou de que está a se disseminar uma visão mais clara do seu anacronismo, ou dos limites mais estreitos em que ela se justifica. Na consecução do referido objetivo central, a tese põe à prova, com base na legislação brasileira vigente, os seguintes possíveis fundamentos da vedação: (a) proteção do devedor; (b) repressão à usura; (c) caráter inderrogável da via judicial como forma de execução; (d) interesse social em impedir a difusão do pacto comissório; e (e) preservação da par conditio creditorum. A conclusão que se alcança é que não existe explicação, senão a de cunho apenas histórico, sobre o porquê de a vedação continuar sancionada por nulidade no direito brasileiro. A partir disso, propõe-se a reconstrução de um sentido para a proibição do pacto comissório, baseada na licitude do pacto marciano e na disciplina da excussão das garantias já nominadas em dinheiro. Essa iniciativa identifica como cerne da reprovabilidade do pacto comissório o risco de desproporção entre o montante da dívida e o valor de mercado do bem dado em garantia. Dessa constatação, e do quanto mais resulta da pesquisa, emergem certas sugestões de aperfeiçoamento legislativo. A tese é complementada pela análise dos julgados dos tribunais superiores brasileiros (STF e STJ) que, ao longo dos últimos cinquenta anos, debateram a extensão da proibição do pacto comissório. A parte final do trabalho aponta certas questões da economia e da cultura que se entende estarem também envolvidas na proibição do pacto comissório. / The thesis main purpose is to identify the possible reasons for prohibiting the pacto comissório and to test them by contrast with the provisions of Brazilian Law. In terms of method, this goal is attained as an exercise of legal reasoning, grounded on the ideas of rational reconstruction (MACCORMICK) and on the assumption of the rational lawmaker (FERRAZ JR.). The essay starts by discussing (a) the meanings of the terms in the expression pacto comissório and (b) the function and the structure of the clause, under the theoretical assumption of its conformity with the Law. After such discussion, the thesis points out the presence of the prohibition in certain foreign legislations and also in the Brazilian Laws. This leads to the perception that, although the prohibition remains largely present, there are signs that it is being eroded, or that it is becoming clear that it is outdated, or that may be justified in a much narrower sense. While pursuing its central objective, the essay tries out, in light of Brazilian Law, the following possible reasons for prohibiting the pacto comissório: (a) the protection of the debtor; (b) the repression to the usury; (c) the judicial foreclosure as the mandatory form for the enforcement of security interests; (d) the social interest in avoiding the dissemination of the pacto comissório; and (e) the observance of the par conditio creditorum rule. The conclusion that arises from this test is that there is no explanation, except for a historical one, for the prohibition of the pacto comissório to remain sanctioned by nullity in Brazilian Law. The thesis suggests then the reconstruction of a reasonable meaning for the prohibition, which takes into account the legitimacy of the pacto marciano and the legal discipline of the security interests over money or money-like assets. This initiative identifies the risk of discrepancy between the amount of the debt and the market value of the collateral as the real core of the rule prohibiting the pacto comissório. From this conclusion, and from what else is perceived by the research, certain suggestions for enhancing the quality of Brazilian legislation are presented. The essay is complemented by the analysis of the decisions rendered by Brazilian superior courts (STF and STJ) during the last fifty years, regarding the extension of the prohibition of the pacto comissório. A last part of the thesis points out certain economic and cultural issues that are also considered involved in the prohibition of the pacto comissório.
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Gestion d’énergie de véhicules multi-sources électriques et hybrides au travers de la représentation énergétique macroscopique / Energy management of multi-sources electric and hybrid vehicles using energetic macroscopic representationCastaings, Ali 31 May 2016 (has links)
Les véhicules routiers sont à une étape majeure de leur histoire. Face aux enjeux actuels d’ordre économiques et environnementaux, le véhicule routier du futur se doit d’être le moins énergivore et avoir une empreinte environnementale la plus réduite possible. Les véhicules multi sources représentent des solutions intéressantes afin de répondre à ces préoccupations. Cependant, ces véhicules utilisent des systèmes de propulsion particulièrement complexes tant au niveau de leur architecture que de leur commande. En particulier, la gestion des différentes sources d’énergie représente un point clé pour l’efficacité énergétique et environnementale des véhicules à concevoir. Elle devient un réel challenge dès que l’on dépasse le nombre usuel de deux sources comme dans le cas des véhicules hybrides actuels et des véhicules électriques mixtes (batterie et supercondensateurs). L’objectif des travaux relatifs à cette thèse est de proposer une méthodologie structurée pour la synthèse de la gestion d’énergie en temps réel, de véhicules multi-sources électriques ou hybrides. Cette démarche s’appuie sur une approche systémique utilisant la modélisation et la Représentation Energétique Macroscopique (REM) en tant qu’outil d’aide à la synthèse des modèles et de la commande associée. Une démarche systématique pour la synthèse des stratégies basées sur la commande optimale a été ensuite associée à cet ensemble profitant de la REM comme outil structurant. En effet, la REM respectant la causalité « physique » (causalité intégrale) d’une part, et permettant d’effectuer une distinction claire entre la commande dite « locale » et le niveau « stratégie » d’autre part, la formulation du problème de commande optimale est réalisée de manière efficace et structurée. Ainsi, en partant du cas du véhicule électrique avec un système multi-source batterie/supercondensateurs déjà étudiée dans la littérature, la méthode a été appliquée pour la synthèse d’une loi de gestion d’énergie basée sur la commande optimale. Ensuite, des sources ont été rajoutées pour passer au cas de trois sources en incluant une Pile à combustible puis quatre sources en rajoutant un groupe électrogène. Les principes développés sont validés par simulation et par l’intermédiaire de tests expérimentaux, afin de s’assurer entre autres, de la faisabilité en temps réel des stratégies développées. / Road vehicles are at a turning point of their history. In order to face economic and environmental challenges, road vehicle of the future must be less energy-consuming and less polluting. Multi sources vehicles represent interesting solutions in order to comply with these challenges. However, these vehicles use particularly complex propulsion systems, both on the architecture level and the control level. The management of the different energy sources represents a key issue for the energy efficiency of the vehicles to be designed. It becomes a real challenge as soon as one exceeds the usual number of two sources, as in current hybrid vehicles and mixed electric vehicles (battery and supercapacitors). The objective of the works relative to this thesis is to propose a structured method for the synthesis the energy management in real time, of electric or hybrid multi-sources vehicles. This approach is based on a systemic approach using the modeling and Energetic Macroscopic Representation (EMR) as a tool of assistance to the synthesis of the models and the related control. A systematic way for the synthesis of the strategies based on optimal control, has been associated benefitting from EMR tool. Indeed, EMR respecting “physical” causality (integral causality) on the one hand, and giving a clear distinction between the control level known as “local” and the “strategy” level on the other hand, the formulation of the optimal control problem is carried out and efficiently structured. Thus, on the basis of the electric vehicle case with a multi-source system battery/supercapacitors already studied in the literature, the method was applied for the synthesis of an energy management law based on the optimal control. Then, sources were added to pass to the case of three sources by including a Fuel cell, then four sources by adding a generator set. The developed principles are validated by simulation and experimental tests, in order to assess the feasibility in real time of the developed strategies.
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Hotell Bellevue i Hjo : ett modernistiskt byggnadsprojekt i sekelskiftesmiljöJenemark, Jesper January 2012 (has links)
Hotell Bellevue byggdes i anslutning till den tidigare vattenkuranstaltens villor från 1880-talet i Hjo stadspark. Hotellet stod färdigt 1971 och ritades av arkitekt Hans-Erland Heineman (1919-2003). Jag undersöker i denna uppsats historien bakom byggnadsprojektet och analyserar dels hur byggnaden gestaltats i förhållande till arkitektens tidigare arbeten och dels byggnadens förhållande till den omgivande miljön. Jag har försökt kartlägga den samtida diskursen, vilket har gjort att jag lagt stor vikt vid att undersöka hur byggnadsprojektet redovisades i den lokala tidningen. Analysen av byggnadens anslutning till platsen har jag relaterat till de två arkitekturteoretikerna Rem Koolhaas och Kenneth Framptons olika sätt att se på arkitektur. Hjo stadspark anlades i slutet av 1800-talet och var då en parkanläggning till Hjo Vattenkuranstalt. Kuranstalten var fullt utbyggd vid sekelskiftet 1900 och Hjo fungerade då som en turistort för den semestrande borgarklassen. Kuranstaltens hotell- och restaurangbyggnad brann ned 1932 och kurorten gick några år senare i konkurs. Efter nästan fyrtio års diskussioner fanns 1969 plötsligt en stor politisk enighet om att ett nytt hotell skulle byggas. Det fanns flera orsaker till detta samförstånd, där det viktigaste kanske var att stadens befintliga hotell var konkursmässiga samtidigt som staden på nytt försökte positionera sig som en turistort. Hotell Bellevue är byggt i modernistisk stil och har ett eget uttryck som skiljer sig markant från kurortens trävillor i utsmyckad panelarkitektur. Den tydligaste influensen till Hotell Bellevue är Frank Lloyd Wrights villaarkitektur i präriestil. Vid ett första ögonkast ser det ut som Hotell Bellevue inte tar någon som helst hänsyn till platsen, men byggnaden har faktiskt anpassats till omgivningen. Tydligast är anpassningen till topografin och det finns även indirekta kopplingar till den omgivande bebyggelsen. Den viktigaste egenskapen är dock att byggnaden med byggnadsmaterial och formspråk speglar den tid då den byggdes.
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Objective Quantification of Daytime SleepinessHodges, Amanda E 07 May 2011 (has links)
BACKGROUND: Sleep problems affect people of all ages, race, gender, and socioeconomic classifications. Undiagnosed sleep disorders significantly and adversely impact a person’s level of academic achievement, job performance, and subsequently, socioeconomic status. Undiagnosed sleep disorders also negatively impact both direct and indirect costs for employers, the national government, and the general public. Sleepiness has significant implications on quality of life by impacting occupational performance, driving ability, cognition, memory, and overall health. The purpose of this study is to describe the prevalence of daytime sleepiness, as well as other quantitative predictors of sleep continuity and quality.
METHODS: Population data from the CDC program in fatigue surveillance were used for this secondary analysis seeking to characterize sleep quality and continuity variables. Each participant underwent a standard nocturnal polysomnography and a standard multiple sleep latency test (MSLT) on the subsequent day. Frequency and chi-square tests were used to describe the sample. One-Way Analysis of Variance (ANOVA) was used to compare sleep related variables of groups with sleep latencies of <5 >minutes, 5-10 minutes, and >10 minutes. Bivariate and multivariate logistic regression was used to examine the association of the sleep variables with sleep latency time.
RESULTS: The mean (SD) sleep latency of the sample was 8.8 (4.9) minutes. Twenty-four individuals had ≥1 SOREM, and approximately 50% of participants (n = 100) met clinical criteria for a sleep disorder. Individuals with shorter sleep latencies, compared to those with longer latencies reported higher levels of subjective sleepiness, had higher sleep efficiency percentages, and longer sleep times. The Epworth Sleepiness Scale, sleep efficiency percentage, total sleep time, the presence of a sleep disorder, and limb movement index were positively associated with a mean sleep latency of <5 >minutes.
CONCLUSIONS: The presence of a significant percentage of sleep disorders within our study sample validate prior suggestions that such disorders remain unrecognized, undiagnosed, and untreated. In addition, our findings confirm questionnaire-based surveys that suggest a significant number of the population is excessively sleepy, or hypersomnolent. Therefore, the high prevalence of sleep disorders and the negative public health effects of daytime sleepiness demand attention. Further studies are now required to better quantify levels daytime sleepiness, within a population based sample, to better understand their impact upon morbidity and mortality. This will not only expand on our current understanding of daytime sleepiness, but it will also raise awareness surrounding its significance and relation to public health.
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Design och Kalibrering av mätrigg för Poly-V remmar / Design and calibration of a measuring rig for poly-v beltsHåkman, Marcus, Tillberg, Max January 2011 (has links)
Scania är en av världens största tillverkare av lastbilar, bussar och marina motorer och examensarbetet har utförts i syfte att utveckla en ny remmätrigg för att bättre kunna verifiera slitage, livslängd och töjning efter olika testcykler på Poly-V remmar. Riggen skall utföra mätningar enligt standard SAE-J1459 och klara att mäta remlängder mellan 1000-3300 mm. Därtill måste konstruktionen vara utformad enligt gällande säkerhetsföreskrifter och ergonomiska aspekter beaktas. Mätningar av Poly-V remmar sker efter principen att remmen spänns in mellan två remskivor med en kraft på 100 N per ribba. Vid examensarbetets start fanns en äldre mätrigg att tillgå, vilken inte längre är i bruk p.g.a. att den inte uppfyller alla krav för mätprocessen. Den har dock använts i syfte för att identifiera ergonomi- och säkerhetsrisker. Påvisade risker har sedan beaktats vid utformningen av koncept, för att begränsa dessa vid konstruktion av den nya mätriggen. Konstruktionen av den nya remmätriggen är framtagen med hjälp av erkänd produktutvecklingsmetodik, med arbete från idé till färdig produkt. Allt i enlighet med en förstudie i konstruktionsmetodik, en konceptstudie som behandlar ett flertal koncept, konceptval och analys av teknisk utrustning som används i den nya konstruktionen samt konstruktionsarbete och utvärdering. Vid examensarbetets slut har en färdigmonterad remmätrigg levererats klar för användning. Konstruktionen klarar att mäta remlängder mellan 1000-3300 mm och upp till tolv ribbor. Mätprocessen enligt SAE-J1459 kan utföras samtidigt som riggen är utformat med ergonomi och säkerhet i åtanke. Tillhörande remmätriggen finns en användarmanual som beskriver rutiner kring användning av utrustningen, risker och själva mätprocessen steg för steg. I rapporten bilagas en förstudie inom ergonomi och säkerhet, som har utförts vid examensarbetets första fas med syfte att användas som grund vid utformningen av den nya riggen. Det för garantera att hänsyn är tagen till gällande ergonomi- & arbetsmiljö-föreskrifter. / Scania is one of the World greatest producers of trucks, busses and marine engines. The purpose of the master thesis has been to develop a new measuring rig for Poly-V belts, to better be able to verify wear, duration and elongation at different testing cycles. The rig shall do measurements following the SAE-J1459 standard and be able to perform on belts with length between 1000-3300 mm. In addition, the design must be made in accordance with safety regulations and ergonomic aspects. Measurement of Poly-V belts are carried out by straining the belt between to pulleys with a force of 100 N per crossbar. At the project start access was granted to an old measuring rig, which is no longer in use due to not fulfilling the requirements for the measuring procedure. However, it has been used to identify ergonomic and safety gaps. The development of new concepts has then been carried out with those gaps in mind. The design of the new measuring rig is developed by using proven product development methodology, which covers work from idée to completed product. That includes accordance with a pre-study in design methodology, a concept study which deals with a number of concepts, the selection of concepts and an analysis of the technical equipment used in the new design during the product design. The result of the thesis is a completed rig, delivered and ready to use. The rig is capable of measuring ribbed belt length between 1000-3300 mm and up to twelve ribs. Measurement process according to SAE-J1459 can be performed meanwhile the rig is designed with ergonomics and safety aspects. A user manual describing the use of equipment, risks and the actual measurement process step by step is also included with the rig. The report annexes a pre-study of ergonomic and safety, which has been written in the initial phase of the thesis. The pre-study has been used as a guide for the design of the new rig, taking into consideration the existing regulations from different acquis.
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Strategic Way Of Design In Rem Koolhaas' / Parc De La Villette ProjectOzkan, Ozay 01 December 2008 (has links) (PDF)
It is inevitable to observe that, in an urban field any architectural enterprise is subject to changing political, financial, technological and cultural demands. The pressure of these ever-changing forces attempts to modify and replace the initial program and the activities associated with the architectural product. The lifespan and the success of the resulting edifice depend on its ability to respond to such changes. Nevertheless, these ever-changing forces are naturally ambiguous and unpredictable so that architectural program becomes indeterminate. This thesis claims that in order to deal with the programmatic indeterminacy in an urban context, a strategic approach should be employed throughout the design process. Therefore, the thesis critically analyzes the strategic way of design to understand its working principles via examining the Parc de la Villette competition project of Rem Koolhaas/OMA. The mechanism of strategic way of design, how it works, and how it is constructed are the main focus of the thesis.
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Anorganische Kolloide im Wasser der ElbeOpel, Karsten, Hüttig, Gudrun, Zänker, Harald 31 March 2010 (has links) (PDF)
Das Wasser der Elbe auf der Höhe von Dresden enthält anorganische Kolloidpartikel, deren Partikelgrößenverteilung nahezu den gesamten kolloidalen Definitionsbereich (1 nm bis 1 µm) überstreicht und die vor allem aus sekundär ausgeschiedener amorpher Kieselsäure sowie aus Oxyhydroxiden des Fe, Al und Mn bestehen. Als wichtigstes Schwermetall führen sie Zn. Ihre Konzentration liegt unter 5×10-1 mg/l, um etwa Faktor 30 unter der Konzentration der Schwebstoffe des Elbwassers (Partikel >1 µm). Wegen ihrer hohen spezifischen Oberfläche sind die Kolloidpartikel als potentielle Träger für Schadstoffe trotz dieser geringeren Massekonzentration nicht gegenüber den Schwebstoffen zu vernachlässigen. Die in der Elbe gemessene Partikelgrößenverteilung ähnelt derjenigen, die zu einem früheren Zeitpunkt im Rhein gefunden worden war. Auch die chemische Zusammensetzung der Kolloidpartikel in der Elbe ist der der Partikel des Rheins ähnlich. Die Konzentration der Kolloidpartikel in der Elbe war aber um Faktor 5 bis 10 höher als im Rhein. Grund für letzteres ist wahrscheinlich der höhere Gehalt des Elbwassers an gelöstem Kohlenstoff (DOC). Im "Bulk" eines Flusses sind kolloidgetragene Schadstoffe - anders als schwebstoffgetragene - vermutlich fast genauso mobil wie echt gelöste. Unterschiede zwischen den Transportgeschwindigkeiten der kolloidgetragenen und der echt gelösten Spurenstoffe treten in bestimmten Situationen auf, in denen das Wasser den "Bulk" eines Flusses verlässt (Sickerbereich unter dem Fluss, Ästuar). Es werden Schlussfolgerungen über die Rolle von Kolloidpartikeln im Ökosystem eines Flusses gezogen und noch bestehende Forschungsdesiderate benannt.
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