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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Experimentally validated multiscale thermal modeling of electronic cabinets

Nie, Qihong 20 August 2008 (has links)
Thermal characterization of electronic cabinets is becoming increasingly important, due to growing power dissipation and compact packaging. Usually, multiple length scales of interest and modes of heat transfer are simultaneously present. A steady reduced order thermal modeling framework for electronic cabinets was developed to provide an efficient method to model thermal transport across multiple length scales. This methodology takes advantage of compact modeling at the chip or component level and reduced order modeling at subsystem and cabinet levels. Compact models, which were incorporated into system level simulation, were created for components, and reduced order models (ROMs) were developed using proper orthogonal decomposition (POD) for subsystems and system. An efficient interfacial coupling scheme was developed using the concept of flow network modeling to couple the heat and mass flow rates and pressure at each interface, when interconnecting ROMs together to simulate the entire system. Thermal information was then subsequently extracted from the global modeling and applied to the component model for detailed simulation. A boundary profile-matching scheme for ROM of each subsystem was developed to broaden the applicability of the multi-scale thermal modeling methodology. The output profiles of the subsystem upstream can be transferred to the input profiles of the subsystems downstream by adding necessary flow straightening ducts during the snapshots generation process. A general method to create dynamic multi-layer compact models for components and modules was developed. These dynamic compact models were incorporated into enclosure level simulation. The dynamic reduced order model for the enclosure was developed using POD. The transient multi-scale thermal modeling approach was illustrated through an electronic enclosure with insulated gate bipolar transistor (IGBT) module. The multiscale thermal modeling methodology presented here was validated through experiments conducted on a simulated electronic cabinet and the test vehicle with hybrid cooling technique. The latter incorporated double-sided cooling with hybrid forced air convection, thermoelectric cooling, and micro-channel liquid cooling. The overall multi-scale modeling framework was able to reduced numerical models containing 107 DOF down to around 102, while still retaining an approximation accuracy of around 90% in prediction of chip junction temperature rises, compared to measurements.
32

Den svenska vallanläggningens ursprung: Låt brons och keramik leda vår väg / The Origin of the Swedish Rampart Enclosures: Let Bronze and Ceramics guide our way.

Olsson Eriksson, Linus January 2018 (has links)
The function and symbolism of the Swedish bronze age rampart enclosures has been debated since the late 1800´s. Arguments highlighting their function as fortifications and/ or as ritual centres has been passed back and forth in what today seems to be a subject in a standstill. Very little has been done in comparing the Swedish enclosures with their European equivalents when it comes to the understanding of function. In the early 1990´s their origin in the Lausitz culture of the Late Bronze Age was put forth by several archaeologists, but one needs to keep in mind that this was a time where the Lausitz culture was an increasingly popular subject for Swedish archaeologists to study. In time the similarities between the materials came to be questioned from both an architectural and a chronological standpoint. This paper has therefore been focused on re-examining the Swedish rampart enclosures relation to the European hill forts and fortified settlements. By examining its relations to the import of bronze and ceramics between the southern and eastern coastal areas of the Baltic Sea area and Scandinavia around 1300­-1000 BC, my main goal was to provide an updated and valid theory for the origins of the earliest Swedish rampart enclosures from the same time. Based on the analysis presented in this paper I have, to some extent, been able to distance the earliest Swedish rampart enclosures from the previous Lausitz origin theory. The conclusion is instead that an origin is to be sought in the earlier Únětice culture and it´s rampart fortified settlements from between 1800-1500 BC.
33

Educação ambiental em zoológicos do nordeste paulista para a conservação da onça parda (Puma concolor) : reflexões sobre atividades e estruturas educadoras / Environmental Education at zoos from Sao Paulo northeastern State (Brazil) for cougar (Puma concolor) conservation : thinking about activities and facilities that educates

Oliveira, Sara Monise de 05 May 2015 (has links)
Submitted by Daniele Amaral (daniee_ni@hotmail.com) on 2016-09-26T19:33:49Z No. of bitstreams: 1 TeseSMO.pdf: 13131734 bytes, checksum: eefbff0faf4d283aecbbbe364f540884 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-04T18:39:58Z (GMT) No. of bitstreams: 1 TeseSMO.pdf: 13131734 bytes, checksum: eefbff0faf4d283aecbbbe364f540884 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-04T18:40:06Z (GMT) No. of bitstreams: 1 TeseSMO.pdf: 13131734 bytes, checksum: eefbff0faf4d283aecbbbe364f540884 (MD5) / Made available in DSpace on 2016-10-04T18:40:14Z (GMT). No. of bitstreams: 1 TeseSMO.pdf: 13131734 bytes, checksum: eefbff0faf4d283aecbbbe364f540884 (MD5) Previous issue date: 2015-05-05 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Zoos house many specimens of native fauna and have great potential to contribute to Environmental Education for biodiversity conservation. However, some studies have pointed that even when these institutions carry on biodiversity conservation actions, this subject may be presented in their educational activities or exhibitions. To investigate the potential of zoos in Environmental Education for biodiversity, we chose the cougar (Puma concolor) conservation as motivating topic. It was selected for the reason that this specie is important to biodiversity maintenance in São Paulo State and because there are many challenges in education for big predators conservation. The purpose of this study was to identify environmental education for the cougar conservation strategic actions that zoos could be do; to discuss the educational intent on animal’s exhibition in zoos nowadays; and to analyze the cougar grounds for their potential as facilities that educates for the conservation of this specie. Adopting Freire principles, that grounds the critical environmental education and a hermeneutic research approach, this thesis was set up as a collective instrumental qualitative study case. The research had a diagnostic stage involving five zoos from Sao Paulo northeastern, in which the research first purpose was developed, and a further analysis stage performed with three of these institutions to address the other two purposes of this study. To collect information, we mainly use zoos technical and educational teams interviews, exhibition and cougar exhibit observations; and, finely, informative stuff, websites and technical documents analyses focused on enclosures and animals. The main result of diagnostic was that any specific cougar educational activity had been performed. But, the issue was extremely important for these institutions, which reported many cougars rescues, including some that occurred with animals on display. The teams believe that activities such as campaigns between Sao Paulo State zoos could improve the development of educational stuffs and facilities that educates for this specie conservation. From second stage of the research, we highlight there are two purposes regarding to animals display: firstly it’s to provide close contact with animals and secondly it’s to educate people for nature conservation. These purposes are coherent with zoos conservation goals and environmental education actions. Although, on an educational exhibition it is necessary to set up the balance between elements that explore each one of these purposes. In this sense, the analysis of cougar exhibits shows that the enclosures and its labels doesn’t has been focused on biodiversity conservation. Mediation about this topic it has been done mainly by educators. That reveals enclosures weaknesses on role as facilities that educates, but their potential could be expanded with additional information inclusion that contextualizes the cougar in their locality. / Os zoológicos são instituições que abrigam diversos espécimes da fauna nativa e que possuem grande potencialidade de contribuírem na educação ambiental para a conservação da biodiversidade. Contudo, alguns trabalhos vêm apontando, que mesmo quando essas instituições realizam ações de conservação da biodiversidade, essa temática pode não estar presente em suas ações educativas ou em suas exposições. Para investigarmos o potencial dos zoológicos nas ações de educação ambiental para a biodiversidade, escolhemos como tema motivador a conservação da onça parda (Puma concolor). Esse tema foi escolhido em função da importância da conservação dessa espécie para a manutenção da biodiversidade no interior do estado de São Paulo e dos desafios existentes nas ações de educação para a conservação de grandes predadores. Os objetivos foram: identificar linhas de ação nas quais os zoológicos podem atuar na educação ambiental para a conservação das onças pardas; discutir a intencionalidade educadora na exposição dos animais em zoológicos na atualidade; e analisar os recintos de onças pardas avaliando seu potencial enquanto estruturas educadoras para a conservação dessa espécie. Com base em princípios freirianos que fundamentam a perspectiva crítica de educação ambiental e em uma abordagem hermenêutica de pesquisa, esse trabalho se constituiu como um estudo de caso qualitativo instrumental coletivo. A pesquisa teve uma etapa de diagnóstico junto a cinco zoológicos do nordeste paulista, com os quais foi desenvolvido o primeiro objetivo, e uma etapa de análise aprofundada, realizada junto a três dessas instituições para executar os outros dois objetivos do estudo. Para a coleta de informações utilizamos principalmente entrevistas às equipes técnicas e educativas das instituições participantes, observações das exposições e dos recintos de onça parda e análises de materiais informativos, sites e de documentos técnicos sobre os recintos e animais. Como principal resultado do diagnóstico obtivemos que nenhuma atividade educativa específica sobre a onça parda havia sido realizada, mas que o tema era extremamente relevante para as instituições, pois foram relatados atendimentos de onças pardas acidentadas, incluindo os animais que estão em exposição. As equipes consideraram que atividades como campanhas articuladas entre os zoológicos paulistas poderiam ser positivas para o desenvolvimento de material didático e estruturas educadoras para a conservação da espécie. Da segunda fase da pesquisa, destacamos como principais resultados a existência de duas intencionalidades com relação à exposição dos animais: proporcionar o contato próximo com o animal e educar as pessoas para a conservação da natureza. Essas intencionalidades são coerentes com os objetivos de conservação e educação ambiental dos zoológicos. No entanto, para que uma exposição seja educativa é importante que haja um balanço entre elementos que abordem cada uma delas. Nesse sentido a análise dos recintos de onça parda revelou que a contextualização promovida pela estrutura física dos recintos e pelas placas não possuem focos na conservação da biodiversidade. A mediação para essa temática é feita principalmente pelas educadoras e educadores. Isso revela fragilidades nos recintos enquanto estruturas educadoras, que podem ter suas potencialidades ampliadas com a inserção de elementos complementares que auxiliem na contextualização da onça parda na realidade local.
34

To be diurnal or nocturnal: the interplay of energy balance and time of activity in subterranean rodents (Ctenomys aff. knighti) and laboratory mice (Mus musculus) / Ser diurno ou noturno: a relação entre balanço energético e padrões temporais diários de atividade em roedores subterrâneos (Ctenomys aff. knighti) e camundongos de laboratório (Mus musculus)

Patrícia Tachinardi Andrade Silva 08 May 2017 (has links)
Studies that show discrepancy between nocturnal and diurnal activity under laboratory and field conditions, respectively, have become increasingly common in rodents and suggest that the definition of temporal niche is far more plastic than originally suspected. Recently, it has been proposed that factors that challenge the animal\'s energy balance play an important role in temporal niche switches. Food availability and environmental temperatures could then be one of the fundamental differences between field and laboratory that could alter the temporal daily pattern of activity. In laboratory, animals are fed ad libitum, while in nature they need to expend energy for foraging. The \"circadian thermo-energetics hypothesis\" suggests that daytime activity could be a response to the high energetic costs of foraging, allowing the animal to save energy during the cooler night hours by resting and taking shelter in burrows where temperatures are higher than on the surface. In this thesis, we explored the interplay of plasticity in nocturnal/diurnal activity definition and energetic metabolism in two rodent species, tuco-tucos (Ctenomys aff. knighti) and laboratory mice (Mus musculus). Tuco-tucos are subterranean rodents which face peculiar energetic challenges in their habitat and were shown to be diurnal in the field and nocturnal in the laboratory. We characterized how their energy expenditure varies across day and night and described the peculiar finding of some factor inside the metabolic chamber being itself a trigger for the nocturnal to diurnal switch. Moreover, we estimated the amount of energy tuco-tucos would save by being diurnal in the field, by combining metabolic rate measurements at various ambient temperatures with records of environmental temperature in the tuco-tuco\'s natural habitat. We also described further investigations of circadian plasticity in both locomotor activity and body temperature of laboratory mice subjected to food restriction in semi-natural conditions. The findings of these three studies provided valuable evidence for the discussion of the role of environmental factors, particularly energetic challenges, in the plasticity of daily rhythms / Estudos que apontam discrepâncias entre atividade noturna e diurna, respectivamente, sob condições de laboratório e de campo, estão cada vez mais comuns em roedores e sugerem que a definição de nicho temporal é muito mais plástica do que se suspeitava inicialmente. Recentemente, foi proposto que fatores que desafiam o balanço energético do animal desempenham um papel importante em mudanças de nicho temporal. A disponibilidade de alimento e as temperaturas ambientais poderiam ser algumas das diferenças fundamentais entre campo e laboratório, os quais poderiam alterar o padrão temporal de atividade diária. No laboratório, os animais são alimentados ad libitum, enquanto na natureza eles precisam gastar energia para forrageamento. A \"hipótese circadiana termoenergética\" sugere que a atividade diurna pode ser uma resposta aos altos custos energéticos do forrageamento, permitindo que o animal economize energia durante as horas mais frias da noite, descansando e se abrigando em tocas onde as temperaturas são mais altas do que na superfície. Nesta tese, exploramos a interação entre a plasticidade da definição noturnalidade/diurnalidade e o metabolismo energético em duas espécies de roedores, o tuco-tucos (Ctenomys aff. knighti) e o camundongo de laboratório (Mus musculus). Tuco-tucos são roedores subterrâneos que enfrentam desafios energéticos peculiares em seu habitat e verificamos que são diurnos em campo e noturnos em laboratório. Nós caracterizamos a variação de seu gasto energético ao longo do dia e da noite e descrevemos o achado peculiar de que algum fator presente no interior da câmara metabólica pode ser um gatilho para a mudança de noturnalidade para diurnalidade. Além disso, estimamos a quantidade de energia que os tuco-tucos economizariam ao serem diurnos em campo, combinando medidas de taxa metabólica em várias temperaturas ambientes com registros dessa temperatura no habitat natural do tuco-tuco. Descrevemos também investigações adicionais sobre a plasticidade circadiana na atividade locomotora e na temperatura corporal de camundongos submetidos à restrição alimentar, em condições seminaturais. Os achados desses três estudos forneceram evidências valiosas para a discussão do papel dos fatores ambientais, particularmente os desafios energéticos, na plasticidade dos ritmos diários
35

Ny tid över tegarna : Nyodling och skifte i Torstuna härad 1750-1914

Lundqvist, Maja January 2017 (has links)
The purpose of this thesis is to elucidate the importance of the enclosure movement for the agricultural development in the area of Mälardalen, Sweden. This is done through a case study of Torstuna härad between the years 1750-1914 by sampling five points in time. By studying the long term development of land reclamation and its correlation with meadow acreage, crop rotation and animal stock the thesis argues that the the radical enclosures in the 1850’s was a course of action to regain opportunities for agricultural expansion. The most intense period of land reclamation was after the implementation of radical enclosure which brought with it a change from communal land use to private ownership. Private property rights meant a new set of advantages for the individual farmer to plan and invest and balance the arable and the meadow.
36

Bedeutung von externen Nährstoffeinträgen und pelagischer Nahrungsnetzstruktur für die Sedimentation und Phosphorrücklösung aus den Sedimenten von Seen

Rychła, Anna 08 February 2011 (has links)
Externe Einträge von Nährstoffen, vor allem von Phosphor, fördern die Phytoplanktonentwicklung und sind damit die primäre Ursache für die Verschlechterung der Gewässergüte in Seen. Die pelagische Nahrungsnetzstruktur kann dabei sowohl positiv als auch negativ auf die Gewässergüte einwirken. Deshalb lässt sich der Gewässerzustand durch eine gezielte Steuerung der Räuber-Beute-Verhältnisse verändern. In der vorliegenden Arbeit wurden Ergebnisse der Groß-Enclosure-Experimente zu den Auswirkungen von Nährstoffen (mit/ohne Zugabe von Nährstoffen) sowie von einer manipulierten Nahrungsnetzstruktur (mit/ohne Zugabe von planktivoren Fischen) auf die pelagische Phyto- und Zooplanktongemeinschaft eines thermisch geschichteten Sees (Dagowsee, Brandenburg) präsentiert. Im Schwerpunkt der Untersuchungen lagen dabei die qualitativen und quantitativen Effekte dieser beiden Faktoren auf die Sedimentationsprozesse sowie den mikrobiellen Umsatz von Kohlenstoff und Phosphor im Hypolimnion und an der Sediment-Wasser-Kontaktzone des Sees. Es wurde gezeigt, dass die Manipulation der Nahrungsnetzstruktur sich auf die Menge und Zusammensetzung des Phyto- und Zooplanktons im Epilimnion des Sees sowie auf den quantitativen vertikalen Transport von Kohlenstoff und Phosphor auswirkte, während die unterschiedliche Nährstoffbelastung im Epilimnion die spezifischen Stoffgehalte des Kohlenstoffs und Phosphors im sedimentierten Material beeinflussten. Anhand der Sauerstoff- und Methanmessungen wurde festgestellt, dass die Intensität des mikrobiellen Abbaus der sedimentierten organischen Substanz vor allem von ihrer Menge abhängig war. Weiterhin konnten die Auswirkungen der manipulierten Nahrungsnetzstruktur auf die Effizienz während des Abbaus vom organischen Kohlenstoff in den Laborversuchen nachgewiesen werden. Diese Effekte waren allerdings in den Freilandexperimenten schwer nachweisbar aufgrund der Beteiligung der Abbauprodukte in anderen oxidativ-reduktiven Prozessen, die gleichzeitig im See verliefen. Anhand des Phosphor-Fraktionierungsverfahrens konnte festgestellt werden, dass dieser Stoff nicht organisch sondern zum größten Teil an Eisen und Mangen gebunden sowie labil adsorbiert die Sedimentoberfläche erreichte. An dieser Stelle zeigten diese beiden Fraktionen einen systematischen Unterschied, der nur auf eine Wirkung der epilimnischen Nährstoffkonzentration und nicht auf die des manipulierten Nahrungsnetzes hinwies. Weitere Analysen der Sedimente zeigten starke Transformationen des sedimentierten Phosphors, aufgrund deren vor allem die dominierenden labilen und redoxsensitiven Phosphorfraktionen betroffen waren. Sie wurden zum einen ins Wasser zurückgelöst und zum anderen in die organische Biomasse gespeichert. Die Veränderungen des Phosphorgehaltes in den Sedimenten waren wieder auf die vorherigen Effekte der Nährstoffe als der manipulierten Nahrungsnetzstruktur zurückzuführen. Die Effekte der Nahrungsnetzmanipulation waren also vor allem an der pelagischen Planktongemeinschaft im Epilimnion und an den Sedimentations- und Kohlenumsatzprozessen in tieferen Schichten des Sees zu sehen. Der vertikale Phosphortransport wurde weniger von der Nahrungsnetzstruktur beeinflusst. Dafür spielte dabei die epilimnische Nährstoffkonzentration sowie die Phosphorbindungspotenzial des Wassers für den internen Kreislauf des Stoffes eine wichtige Rolle. / External load of nutrients, above all from phosphorus, promote the phytoplankton development and are with it the primary cause for the deterioration of the waters quality in lakes. Further, the pelagic food web structure can affect the water quality in a positive as well as in a negative way. Therefore, the water trophic state can be changed by a specific control of the predator-prey relations. In the present study the results of the large enclosure experiments to the impact by nutrients (with/without addition of nutrients) as well as by a manipulated food web structure (with/without addition of planktivorous fish) on the pelagic phyto- and zooplankton community of a thermally stratified lake (Dagowsee, Brandenburg) were presented. Furthermore, the qualitative and quantitative effects of these both factors on the sedimentation processes as well as the microbial turnover of settled carbon and phosphorus in the hypolimnion and at the sediment-water layer of the lake were in the main focus of the investigations. It has been shown that the manipulation of the food web structure affected the amount and composition of the phyto- and zooplankton in the epilimnion as well as the quantitative vertical transport of carbon and phosphorus, while the different nutrient load in the epilimnion influenced the specific material content of the carbon and phosphorus in the sedimented material. With the help of the oxygen and methane measurements it was found out that the intensity of the microbial decomposition of the settled organic matter was dependent above all on her quantity. Furthermore, the effects of the manipulated food web structure on the decomposition efficiency of the organic carbon could be proved in the laboratory tests. However, these effects were in the free land experiments hardly provably due to the participation of the endproducts in other redox processes which ran at the same time in the lake. With the help of the phosphorus fractionation procedure could be found out that settled phosphorus for the most part not organically but in iron and manganese bound as well as loosely adsorbed the sediment surface reached. At this point these both forms showed a systematic difference which pointed only to an effect of the epilimnetic nutrient concentration and not on those of the manipulated food web. Other analyses of the sediments showed strong transformations of the settled phosphorus, which influenced above all the dominating labile and redox sensitive phosphorus fractions. They were released, on the one hand, in the water and stored, on the other hand, in the organic biomass. The changes of the phosphorus content in the sediments were to be led on the previous effects of the nutrients than of the manipulated food web structure. To conclude, the effects of the food net manipulation were to be seen above all in the pelagic plankton community in the epilimnion, and further in sedimentation and carbon turnover processes in deeper layers of the lake. The vertical phosphorus transport was influenced of less by the food web structure. Moreover, for it the epilimnic nutrient concentration as well as the phosphorus binding potential of the water played an important role for the internal circulation of the material.
37

Numerical Simulation and Experimental Validation of Fluid Flow and Mass Transfer in an Ammonothermal Crystal Growth Reactor

Moldovan, Stefan Ilie 09 May 2013 (has links)
No description available.
38

Permanencia y cambio en la obra de Mies van der Rohe: los Promontory Apartments como campo de experimentación

Blat Tatay, Andrea 02 September 2024 (has links)
[ES] Durante los años de revisión crítica de la modernidad, muchos cuestionaron la importancia de la obra americana de Mies van der Rohe. Sus magníficos rascacielos fueron considerados pragmáticos e impersonales, como simple arquitectura corporativa. El sentido de los montantes metálicos que recorrían verticalmente sus fachadas era reducido a una mera representación de la estructura, sin considerar su función en la concepción tectónica del edificio y su valor figurativo. Otros cuestionaron la absoluta modernidad de la obra de Mies, investigando la presencia de gestos clasicistas entre la radicalidad de sus proyectos. Estas ideas han persistido explícita e implícitamente en muchos textos sobre su obra. El objetivo de nuestro trabajo es revisar muchos de esos análisis y ampliar el campo de investigación sobre su contribución al desarrollo arquitectónico de la edificación en altura a partir de un caso concreto, los Promontory Apartments. Su estudio en profundidad, de las dos versiones proyectuales: con envolvente de vidrio y acero o de hormigón y ladrillo, constituye el núcleo de esta tesis. Partiendo de un planteamiento fundamentalmente analítico y conceptual, y no meramente descriptivo o técnico, se profundiza en el pensamiento arquitectónico de Mies y su relación con su concepción de la arquitectura como forma tectónica, estudiando la génesis y el desarrollo de los Promontory. En la tesis se analiza el desarrollo del concepto de envolvente en la obra americana de Mies hasta llegar a la versión de vidrio y acero realizada para el cerramiento de los Promontory. Se investiga el sentido y alcance de los prototipos de cerramiento elaborados durante el proceso de proyecto de los Promontory en la obra posterior del arquitecto. En particular, sobre la conceptualización del cerramiento y la evolución de su relación con la estructura y el desarrollo de una nueva gramática arquitectónica con un marcado carácter tectónico. Se investiga cómo el material y la manera de construir la envolvente es decisiva en su concepción de la arquitectura en la mayoría de sus obras. Solo en algunos de sus proyectos para pabellones y viviendas unifamiliares en América, la estructura alcanza un valor arquitectónico sobresaliente. Mies no es estudiado desde la idea de la estructura como arquitectura en esta tesis, sino que se analiza la convergencia entre la objetividad de la tectónica y la búsqueda de una nueva figuración arquitectónica. Se estudia también, entre otros aspectos de su obra, su nueva aproximación al desarrollo de la vivienda colectiva y el origen de los prototipos de edificio que afinará y repetirá sucesivamente. Esta investigación se fundamenta en sus textos, dibujos y otras fuentes originales, aportando nuevas hipótesis y conclusiones. La evolución de su concepción de la arquitectura en su obra americana conduciría al salto conceptual alcanzado con la casa Farnsworth y con su propuesta de una fachada de acero y vidrio para los Promontory Apartments, cuyo desarrollo culminará con el edificio Seagram en Nueva York. Se explorará la coherencia entre el "pensamiento constructivo" de Mies y la formalización del rascacielos. Se mostrará cómo la imagen de los Promontory no es tanto un hecho figurativamente predeterminado, como la consecuencia de la elaboración de soluciones constructivas y técnicas objetivas. Soluciones cuidadosamente meditadas para converger en una forma final dotada de valores estéticos, a lo que Mies denominó "valores espirituales", trasladando la objetividad tectónica más allá de la construcción, "Bauen", para convertirse en "Baukunst" y, en definitiva, transformarla en arquitectura. / [CA] Durant els anys de revisió crítica de la modernitat, molts van qüestionar la importància de l'obra americana de Mies van der Rohe. Els seus magnífics gratacels van ser considerats pragmàtics i impersonals, percebuts com una simple arquitectura corporativa. El sentit dels montants metàl·lics que recorrien verticalment les seues façanes es va reduir a una mera representació de l'estructura, sense considerar la seua funció en la concepció tectònica de l'edifici. Altres van qüestionar l'absoluta modernitat de l'obra de Mies, investigant la presència de gestos clàssics entre la radicalitat dels seus projectes. Aquestes idees han persistit explícita e implícitament en molts textos sobre la seua obra. L'objectiu del nostre treball és revisar moltes d'aquestes anàlisis i ampliar el camp de recerca sobre la seua contribució al desenvolupament arquitectònic de l'edificació en altura a partir d'un cas concret, els Promontory Apartments. El seu estudi en profunditat, de las dos versions proyectuals: amb envolvent de vidre y acer o de formigó y rajola, constituixen el nucli d'aquesta tesi. Partint d'un plantejament fonamentalment analític i conceptual, i no merament descriptiu o tècnic, s'aprofundeix en el pensament arquitectònic de Mies i la seua relació amb la seua concepció de l'arquitectura com a forma tectònica, estudiant la gènesi i el desenvolupament dels Promontory. En la tesi s'analitza el desenvolupament del concepte d'envolvent en l'obra americana de Mies fins a arribar a la versió de vidre i acer realitzada per a l'envolvent dels Promontory. Es investiga el sentit i abast dels prototypes d'envolvents elaborats durant el procés de projecte dels Promontory en l'obra posterior de l'arquitecte. En particular, sobre la conceptualització de l'envolvent i l'evolució de la seua relació amb l'estructura i el desenvolupament d'una nova gramàtica arquitectònica amb un marcat caràcter tectònic. Es investiga com el material i la manera de construir l'envolvent és decisiva en la seua concepció de l'arquitectura en la majoria de les seues obres. Només en alguns dels seus projectes per a pavellons i habitatges unifamiliars als Estats Units, l'estructura assolix un valor arquitectònic destacat. Mies no és estudiat des de la idea de l'estructura com arquitectura en aquesta tesi, sinó analitzant la convergència entre l'objectivitat de la tectònica i la recerca d'una nova figuració arquitectònica. S'analitza també, entre altres aspectes de la seua obra, la seua nova aproximació al desenvolupament de l'habitatge col·lectiu i l'origen dels prototípus d'edifici que afinarà i repetirà successivament. Aquesta investigació es fonamenta en els seus textos, dibuixos i altres fonts originals, aportant noves hipòtesis i conclusions. L'evolució de la seua concepció de l'arquitectura en la seua obra americana conduiria al salt conceptual assolit amb la casa Farnsworth i amb la seua proposta d'una façana d'acer i vidre per als Promontory Apartments, el desenvolupament del qual culminarà amb l'edifici Seagram a Nova York. La investigació explora la coherència entre el "pensament constructiu" de Mies i la formalització del gratacel. Es mostrarà com la imatge de l'edifici no és tant un fet figurativament predeterminat, com la conseqüència de l'elaboració de solucions constructives i tècniques objectives. Solucions cuidadosament meditades per convergir en una forma final dotada de valors estètics, al que Mies va denominar "valors espirituals", traslladant l'objectivitat tectònica més enllà de la construcció, "Bauen", per a esdevenir en "Baukunst" i, finalment, transformarla en arquitectura. / [EN] During the critical review years of modernity, many questioned the significance of Mies van der Rohe's American work. His magnificent skyscrapers were considered pragmatic and impersonal, seen as mere corporate architecture. The meaning of the vertical metal mullions on his facades was reduced to a mere representation of structure, overlooking their function in the tectonic conception of the building. Others questioned the absolute modernity of Mies's work, investigating the presence of classical gestures amidst the radicalism of his projects. These ideas have persisted explicitly and implicitly in many texts about his work. The aim of this thesis is to revisit many of these analyses and to expand the research field on his contribution to the architectural development of high-rise buildings through a specific case, the Promontory Apartments. Its deep research, of the two project versions: with a steel and glass or concrete and brick enclosure, conforms the core of this thesis. Taking a fundamentally analytical and conceptual approach, rather than merely descriptive or technical, we delve into Mies's architectural thinking and its relation to his conception of architecture as tectonic form, studying the genesis and development of the Promontory Apartments. The thesis analyzes the evolution of the envelope's concept in Mies's American work, leading to the glass and steel version created for the envelope of the Promontory. The sense and scope of the envelope prototypes developed during the Promontory design process are investigated in the architect's later works particularly focusing on the conceptualization of enclosure and the evolution of its relationship with the structure, shaping a new architectural grammar with a distinct tectonic character. The research explores how the material and construction method of the envelope are crucial in his conception of architecture in most of his works. Only in some of his projects for pavilions and single-family homes in America does the structure reach outstanding architectural value. This thesis does not study Mies from the idea of structure as architecture but rather analyzes the convergence between the objectivity of tectonics and the pursuit of a new architectural figuration. It also examines, among other aspects of his work, his new approach to the development of collective housing and the origin of building prototypes that he would refine and repeat successively. This research is grounded in his texts, drawings, and other original sources, introducing new hypotheses and conclusions. The evolution of his architectural conception in his American work would lead to the conceptual leap achieved with the Farnsworth House and his proposal for a steel and glass facade for the Promontory Apartments, culminating in the Seagram Building in New York. The investigation will explore the coherence between Mies's "constructive thinking" and the formalization of the skyscraper. It will show how the skyscrapser's image is not so much a figuratively predetermined fact but the consequence of developing objective constructive and technical solutions. Carefully considered solutions converge into a final form endowed with aesthetic values, what Mies referred to as "spiritual values," transcending tectonic objectivity beyond construction, "Bauen", to turn it into "Baukunst" and, finally, becoming architecture. / Blat Tatay, A. (2024). Permanencia y cambio en la obra de Mies van der Rohe: los Promontory Apartments como campo de experimentación [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/207533
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Contribution à l'étude du blindage magnétique basse fréquence de boîtiers dédiés aux véhicules électriques et hybrides / Evaluation of low frequency shielding effectiveness of enclosures dedicated to electric and hybrid vehicles

Frikha, Amin 12 December 2014 (has links)
Avec l’électrification des moyens de transport, nous constatons ces dernières années une augmentation de l’utilisation de l’électronique de puissance et de la puissance mise en jeu dans les véhicules électriques ou hybrides (VEH). A cela s’ajoute une intégration de cette électronique dans des milieux de plus en plus compacts, a conduit à l’apparition de problèmes de la compatibilité électromagnétique (CEM) et d’exposition aux champs électromagnétiques. Pour réduire les effets indésirables des champs électromagnétiques, le blindage électromagnétique est l’une des solutions envisageables. Ces travaux de thèse portent essentiellement sur le blindage magnétique basse fréquence en champ proche des boîtiers contenant des équipements d’électroniques de puissance. Généralement, les boîtiers sont équipés d’ouvertures et de fentes ce qui conduit à une dégradation des performances du blindage magnétique. Nous nous intéressons dans ces travaux de thèse au développement de modèles permettant la prédiction de l’efficacité de blindage magnétique en tenant compte des effets de la diffusion, des ouvertures et des fentes. Ces différents modèles permettront aux concepteurs de maitriser les contraintes liées au blindage magnétique des dispositifs d’électroniques embarquées à bord des véhicules. L’aptitude ou la capacité des méthodes numériques à résoudre les problèmes de diffusion des champs magnétiques dans les tôles minces en présence et en absence d'ouvertures est présentée. Dans le cas de boîtiers munis de fentes de faibles dimensions, des approches basées sur la méthode des moments magnétiques sont développées pour la prédiction de l’efficacité de blindage magnétique. Des bancs de test ont été développés pour valider ces modèles. Dans le cas de fentes de dimensions quelconques, des approches dites "hybrides" associant des méthodes numériques et analytiques ont été développées et validées expérimentalement. Les approches développées ont été appliquées dans le cadre de l’étude d’une application industrielle. / The electrification of transport means, in recent years leads to an increase of the use of the power electronics and the power involved in electric or hybrid vehicles (HEV). With the integration of electronic devices in more compact environments, appear problems of the electromagnetic compatibility (EMC) and the electromagnetic field exposure. To reduce the effects of electromagnetic fields, electromagnetic shielding is one of the possible solutions.This thesis focus mainly on the magnetic shielding at low frequency in near field of enclosures containing power electronics. Usually, the enclosures are equipped with openings and slots which results in degraded performance of the magnetic shield. We develop models for predicting the magnetic shielding taking into account the effects of diffusion, openings and slots.These models will allow designers to control the magnetic shielding constraints of embedded electronic devices in vehicles. The ability or capability of numerical methods to solve the problems of the magnetic fields diffusion in thin sheets in the presence and absence of openings is presented. In the case of enclosures with slots of small dimensions's, magnetic moments approaches are developed for the prediction of magnetic shielding effectiveness. Test benches are developed to validate these models. In the general case, so-called “hybrid” approaches combining the analytical and numerical methods are developed and experimentally validated. The developed approaches are also applied in the framework of an industrial application.
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Delar av en grav och glimtar av en tid : Om yngre romersk järnålder, Tuna i Badelunda i Västmanland och personen i grav X / Parts of a Grave and Glimpses of a Time : A discussion of the Late Roman Iron Age, Tuna in Badelunda in Västmanland and the person in Grave X

Fernstål, Lotta January 2004 (has links)
Grave X was found in 1952 during construction work in Tuna in Badelunda parish, in the province of Västmanland. Objects from this 3rd Century grave were dispersed and the stone grave covering and cist-like wooden burial chamber were cut almost in half as a result of the construction work that unearthed it. The purpose of this dissertation is to create a better understanding of Tuna in Badelunda and to place Grave X and the person buried there in context. Due to my interest in Grave X and the person in this grave, the scope of the study is limited to Tuna during the Late Roman Iron Age. What kind of place may Tuna in Badelunda have been during that time? Which kinds of knowledge may the person in Grave X have possessed and what roles may this person have had in local society? How may this person have acted in Tuna in Badelunda in particular? Why was this person buried in the specific type of structure that was Grave X? To answer these questions, ancient monuments and phenomena in the Tuna area, objects from the grave and construction details of the grave are discussed. Specifically, I examine the name Tuna, stone enclosures, hillforts of Bejby borg-character and travel routes, beads, golden rings in the shape of snakes, vessels and serving utensils, and the stone grave covering and cist-like chamber. Since Grave X was partly ruined when discovered, comparisons are made to about 20 similar graves from other parts of Scandinavia in order to get an idea of what may have been lost from Grave X. A performative-constructive gender perspective is of importance in this dissertation, as well as the concept of creolization. The kinds of knowledge and the societal roles the person in Grave X may have had can be summarized in five categories or contexts of action: production within the (social-political) economy of the farm, ritual performances, physical communication, textile production, and oral performances with the telling of stories and relating of memories. Possible personal strategies in relation to the activities the person in question was involved in are seen as important. One way this dissertation takes up this subject is through the discussion of the role the person may have had in greetings and farewells in the yard of the farm (Sw. tun, gårdsplan). Greetings and farewells were probably of importance, and Tuna is discussed as a crossroads. This means that although a local perspective is advocated in this dissertation, Tuna may not be seen as an isolated community, but rather as a small place that to a great extent partook in the larger world. This can also be seen in Grave X; when the person in this grave was buried, the living made choices that both expressed local traditions and made reference to far-away places. In contrast to the surrounding graves, the person in Grave X was not cremated. One of many possible reasons may have been a desire to emphasize the person’s personality and gender as well as roles in society. / <p>Auktoriserad namnform i LIBRIS: Fernstål, Charlotte, 1974-</p>

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