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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.
281

Estudo da problemática da aplicação de coletores solares para aquecimento de água, no segmento residencial de alto padrão, com base em escalas de projeto arquitetônico e dimensões de planejamento. / Study of the problematic of solar thermal collectors for hot water in high standards houses based on architectonic and planning dimensions.

Bernadette Vechia de Mendonça 20 March 2009 (has links)
A presente Dissertação é um estudo a respeito da problemática da utilização dos Sistemas de Aquecimento Solar Térmico para Aquecimento de Água com Coletores Planos em Circuito Direto, no crítico contexto da construção civil paulista para o ponto de vista da Arquitetura e do Urbanismo. Apesar do potencial solar do país e do padrão construtivo dos condomínios horizontais fechados da Região Metropolitana de São Paulo (RMSP), ainda não há regulamentação do uso do aquecimento solar térmico em alguns de seus municípios-sede. Atualmente tem havido a adesão espontânea ao sistema por parte de moradores das residências desses condomínios, decorrente da busca da redução dos gastos e da crescente conscientização ambiental e divulgação da tecnologia. Porém, ainda há necessidade de uma relação mais sistêmica dos coletores solares com a totalidade dos requisitos da edificação e do meio urbano, mesmo em se tratando da legislação específica. Buscando uma constribuição, aqui se propõe um modelo de estudo dos coletores baseado em escalas construtivas que, juntamente com a compreensão multidimensional do assunto, desafiam a atual dicotomia entre as ferramentas de qualidade e a sustentabilidade do ambiente construído. / The present work studies the problematic of using Solar Hot Water Systems by Direct Circuit, among the critics characteristics of civil construction in the State of São Paulo, Brazil. The point of view is of Architecture and Urban Planning. In spite of the high Brazilian levels of solar irradiation and the constructive pattern of horizontal closed condominiums of the metropolitan region of São Paulo (Brazil), which possess a large concentration of high incoming households, use of solar water heating is still not regulated in some of its comprising municipalities. Nowadays, the search for savings, diffusion of related technologies and raising environmental awareness have led to voluntary uptaking of such systems. Yet, regulation of solar collectors still lacks relating to certification of sustainable building practices, which does not relate to architectonic factors, in particular to main urbanistic features present in each given installation site. This work proposes an architectonic scale based model of studying it in order to pursuit the end of dichotomy between quality and sustainability.
282

Experimentální analýza vybraných systémů kolejnicových upevnění / Experimental Analysis of Chosen Railway Fastening Systems

Tomandl, Vladimír Unknown Date (has links)
Theoretical analysis (i.e. simulation) promoted by the laboratory tests of final product is the important aspect for determination relating to choice and using the new infrastructural constituent. However, the laboratory analysis does not need to make conclusive results in some cases. At that time, it is necessary to complete the process of validation by the measurement in-situ (directly in the track section). The European legislation requires the long-term monitoring of the test constructions in this case. During this time, both the periodic monitoring of the chosen parameters and the following comparison with reference construction are recommended. The reference construction shall be inserted to the same track section and in the same time period as well as the test construction. The track gauge, the longitudinal shifts of rails vis-a-vis the sleepers, the clamping force of fastening, the rail head profile, the sleepers and the state of rail fastenings are possible to classify like the long-term monitored parameters. All these characteristics are so-called static. They are checked in time when no carriages pass through the monitored track section. However, the analysis and determination of the test construction behaviour (dynamic characteristic) are the most accurate by the moving load. Dissertation thesis is focused on measurement and analysis of the dynamic effects at the plain line. The aim of the thesis is the completion of recent system of the new track structures verification for the dynamic parameters observe. Methodology of the measurement and convenient mathematical apparatus for analysing the dynamic effects is proposed.
283

Řešení dynamiky vyvažovací jednotky vznětového řadového čtyřválcového motoru / Balancer Unit Dynamics of Diesel In-line Four-cylinder Engine

Dítě, Jan January 2010 (has links)
Subjekt of this diploma thesis is createing of 3D model of a balancing shafts and a dynamic model of the balancing shaft and needle roller or plain bearings. To decide from the results of dynamic analysis in MBS (Multi-Body-System), which type of bearing is the best for storage the balancing shaft in the engine Zetor type series III.
284

Hydrodynamická ložiska vznětového traktorového motoru / Plain Bearings for CI Tractor Engine

Petr, David January 2010 (has links)
This thesis deals with the hydrodynamic plain bearings tractor diesel engine. The first part is closer acquainted with the hydrodynamic bearing, its principles and materials used. The next part work deals with the multibody system adams-engine. The main part of this work is to model the crank mechanism and its storage in hydrodynamic bearings in the MBS program and the subsequent simulation under different operating conditions.
285

Návrh ojnice vznětového leteckého motoru / Connecting Rod Design of Diesel Aircraft Engine

Maršálek, Ondřej January 2011 (has links)
The thesis deals with complex connecting rod design of two stroke diesel engine with regard to minimising its weight. Three versions of design are suggested and for each of them the stress analyses are implemented and the fatigue safety factors are determined. On the basis of results of implemented analyses and evaluation of all the aspects the most appropriate design is chosen and the production drawing is drawn according to it. In the conclusion, hydrodynamic lubrication plain bearings, which are the integral part of every connecting rod, are designed.
286

Fenomén prázdné galerie / The phenomenon of empty gallery

Brožka, Petr January 2015 (has links)
The doctoral thesis deals with the topic of exihibiting empty gallery space. The purpose is to clarify the specifics that accompany the exhibited empty gallery and to define the essence of more general patterns of exposition in the gallery space. Doctoral thesis also presents the special simple void that generates art itself. Finally, the text reopens a polemic within the institutional theory of art. Doctoral thesis criticizes the established terminology related with exposition of the empty gallery.
287

Porovnání technologií podbíjení koleje / Comparison of Plain Line Tamping Methods

Bombera, Jan January 2016 (has links)
The diploma´s thesis deals with evaluation of adjusted track tamping technology and its comparison with currently used technology. This is based on track geometry parameters measuring and its vertical movement on the test section, which was created on double track Břeclav – Přerov near Rohatec station. On this test section one line was tamped with the currently used method within regular maintenance work and the second line was tamped with the adjusted technology. The technology modification is based on application of increased number of tamping tines squeezing strokes, which results in a creation of bigger and more compacted sleeper bed. The point of this thesis is to verify, that the speed of the track geometry parameters degradation is smaller in case of adjusted technology use. Thanks to that it would be possible to extend the maintenance cycles in case of compliance with track parameters maintenance limits and traffic safety.
288

Polyfunkční dům / Multifunctional Building

Kozáková, Martina January 2016 (has links)
The diploma thesis is based on design of a multifunctional building in Lazany. The object is situated in a build-up area. There is the patisserie and the grocery on the first floor. There is six flats on the second and the third floor. The building has three floors without a cellar. There is a parking for customers and tenantry of building. The object is based on the footings of plaint concrete and it is used the building system POROTHERM. The ceilings are made of ceiling panels SPIROLL and the roof is flat.
289

Etude expérimentale et numérique du transfert hydrique dans la plaine de Sidi Bouzid / Experimental and numerical study of water transfer in the plain of Sidi Bouzid

Boughanmi, Manel 19 December 2018 (has links)
L’objectif est la construction numérique d’un modèle 3D régional de la plaine de Sidi Bouzid permettant la quantification du transfert hydrique et du rôle des crues sur le processus de recharge. Des simulations numériques de l’écoulement ont été réalisées à l’aide de Feflow et validées par des données mesurées in situ. Une conceptualisation des paramètres d’entrée a été réalisée afin de contourner l’absence de données mesurées. L'hétérogénéité de la zone non saturée a un impact significatif sur la variation du flux vertical et la propagation du front d’humidité. Les résultats obtenus en 1D ont été spatialisés à l’échelle de la plaine avec l’objectif de quantifier l’ensemble des flux d’écoulements. L’originalité réside, d’une part, dans la détermination des conditions aux limites appliquées à la surface du sol à partir des hydrogrammes des crues enregistrés et, d’autre part, au modèle conceptuel limitant l’évaporation. Le modèle hydrodynamique a mis en évidence que le bilan hydrique est fortement excédentaire. Les simulations de l’écoulement ont montré que l’approche des épandages de crues au niveau des périmètres surestime la recharge artificielle de la nappe. / The aim of this study is to set up a 3D regional model to quantify water flux in unsaturated-saturated zones and the role of floods on the recharge process. Therefore, numerical flow simulations were conducted using the finite element Feflow that will be validated by measured data. A conceptualization of input parameters was carried out to overcome the absence of measured data. The heterogeneity of the vadose zone have a significant impact on the variation of the vertical flow, the residence time and the propagation of wetting front in the unsaturated zone. The results obtained in 1D were then used to quantify groundwater recharge of the entire area of the study site. The original approach is to derive the time-dependent hydraulic boundary condition of water level at the soil surface of the spreading perimeters by measured flood hydrographs and to develop a limited conceptual model of water uptake by evaporation. The hydrodynamic model showed that the water balance is very important. Flow simulations have shown that the perimeter flooding approach overestimates the artificial recharge of the aquifer.
290

Influence of geometric form deviations on operating parameters in hydrodynamic bearings

Ebermann, Marko 16 May 2018 (has links)
Hydrodynamic plain bearings are important machine elements. They are used in many areas of mechanical engineering, such as turbomachines, crankshaft bearings and gears. The geometry of the lubrication gap elemen-tarily influences the function as shown in several examples of abrupt failures in turbochargers. Due to toleranc-ing, the manufacturing requirements are very high. However, the question remains how large these deviations can be. ISO 12129-2 gives recommendations on form deviations depending on the minimum of plain bear-ing clearance (hmin). Nevertheless, there is no direct reference on the size or the strain on bearing. In DIN 31652-3, the tolerance of the bearing clearance is divided into -1/3 and +2/3 of itself. However, this tolerance merely has an indirect correlation with the size of the bearing and strain on the bearing. If these tolerance recommenda-tions are applied, the function of the plain bearing will not be completely fulfilled. Nonetheless, tolerances pro-vided by standards are used in geometric specifications. If these tolerances are used for in-company manufacturing, this is unproblematic in most cases. But if technical drawings are sent to an external manufacturer, toler-ance limits may be exhausted and the function cannot be ensured. Within the framework of the research project presented here, a tolerance evaluation matrix has been developed. For this, the existing standards were analyzed. In this case, the ignorance of size (diameter and width) and signif-icant operating properties (speed, load, temperature, etc.) are insufficient. The project examined and simulated various possible deviations. Selected form deviations were manufactured. The validation of the simulation results were carried out on 30mm.

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