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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.
51

Estudo das estruturas de membrana: uma abordagem integrada do sistema construtivo, do processo de projetar e dos métodos de análise / Study of membrane structures: an integrated approach of the constructive system, design process and analysis methods

Oliveira, Maria Betânia de 10 April 2001 (has links)
As estruturas de membrana empregadas em coberturas são sistemas construtivos formados principalmente pela membrana estrutural, que ainda tem a função de vedar. As membranas estruturais são folhas flexíveis que resistem às ações externas devido à sua forma, às suas características físicas e ao seu pré tracionamento. O pré-tracionamento da membrana pode ser alcançado, ou através do seu estiramento por meio de cabos (estruturas de membrana protendida por cabos), ou através da atuação da pressão de gases (estruturas pneumáticas). Ambas estão sendo usadas em coberturas de centros esportivos, de áreas comerciais e de construções industriais ou agro-industriais. Todavia, as estruturas de membrana são pouco conhecidas, estudadas e empregadas no Brasil. Neste contexto, este trabalho tem como objetivos sistematizar o conhecimento científico existente sobre o tema e introduzi-lo no Brasil e, também, apontar caminhos para investigação científica sobre as estruturas de membrana no país. Apresenta o sistema construtivo, o processo de projetar e os métodos de análise das estruturas de membrana empregadas em coberturas. Sistematiza o projeto de estruturas de membrana, através de recomendações e de estudo de caso. Propõe um modelo de pesquisa integrado voltado para o desenvolvimento desta tecnologia no Brasil. Este deve auxiliar a coordenação e a compatibilização dos esforços de investigação científica nas diversas áreas do conhecimento envolvidas no desenvolvimento das estruturas de membrana / Membrane structures used in roofs are constructive systems formed mainly by structural membrane, which has also the function of sealing. Structural membranes are flexible sheets that resist to external loads due to their form, to their physical characteristics and to their pre-stressing. The pre-stressing of the membrane can be achieved either through its stretching using cables (surface-tensioned membranes) or through gases pressurization (pneumatic structures). These structures are being utilized in roofs over airports, stadiums, industrial facilities, shopping precincts and buildings for industrial or agricultural use, among others. However, membrane structures are not yet well known, studied and used here in Brazil. In this context, this work has as objectives to systematize the scientific knowledge existent on the theme, to introduce it in Brazil and, also, to point out ways for scientific investigation on membrane structures in this country. This research presents the constructive system, the design process and the analysis methods of membrane structures used in roofs. This work systematizes the membrane structural design, with recommendations and study of case. This work proposes an integrated model of research for this technology development in Brazil. This model should assist the coordination and the mutual appreciation of the scientific investigation efforts in the different knowledge areas involved in the membrane structure development
52

Impact of cold acclimatization on nutrient utilization and enteric methane emissions of beef cows overwintered on low-quality forage diets supplemented with dried distillers grain with solubles

Bernier, Jennilee 21 September 2011 (has links)
This study was conducted to determine if nutrient utilization and enteric methane (CH4) emissions could be improved in overwintering beef cows consuming low-quality forage supplemented with protein in the form of dried distillers grain with solubles (DDGS) in thermal-neutral and cold-stressed environments. Thirty mature, dry and non-pregnant beef cows were divided into three treatment groups and fed diets consisting of low-quality (6.0% crude protein; CP) forage with no DDGS (control, CON), 10% DDGS (borderline sufficient CP, 8.7% CP), or 20% DDGS (excess CP, 11.6% CP). Cold acclimatization did not appear to affect nutrient intake and digestibility by beef cows, but increased N and P excretion by 1.2x and 2.5x, respectively. Cold acclimatized cows reduced energy excretion by 26.8% (7.1 vs. 5.2 ± 0.30% GEI in fall and winter, respectively; P < 0.0001) in accordance with a 33.8% increase in rumen fluid rate of passage (ROP). Supplementation with DDGS improved digestibility of N and P (40.6 vs. 61.2 ± 2.45% N and -23.9 vs. 5.7 ± 5.95% P for CON and 20%DDGS, respectively; P < 0.0001) by increasing digestible substrate in the diet. Protein supplementation increased rumen NH3-N concentrations (1.5, 2.1 and 3.1 ± 0.15 mg 100 mL-1; P < 0.0001) enough to increase rumen fermentation efficiency, resulting in 18.5% lower enteric CH4 emissions when CP was fed in excess of animal requirements. Total excretion of N and P were increased two- and 45-fold, respectively, when excess CP was fed. Reduced enteric CH4 emissions as a result of cold acclimatization suggest an advantage for the Canadian beef herd in terms of environmental sustainability. Supplementing CP in excess of cow requirements may improve nutrient utilization and rumen fermentation efficiency, and mitigate enteric CH4 emissions in beef cows fed low-quality forage diets, but may also contribute to greater N and P loading of soil and ground water.
53

Impact of cold acclimatization on nutrient utilization and enteric methane emissions of beef cows overwintered on low-quality forage diets supplemented with dried distillers grain with solubles

Bernier, Jennilee 21 September 2011 (has links)
This study was conducted to determine if nutrient utilization and enteric methane (CH4) emissions could be improved in overwintering beef cows consuming low-quality forage supplemented with protein in the form of dried distillers grain with solubles (DDGS) in thermal-neutral and cold-stressed environments. Thirty mature, dry and non-pregnant beef cows were divided into three treatment groups and fed diets consisting of low-quality (6.0% crude protein; CP) forage with no DDGS (control, CON), 10% DDGS (borderline sufficient CP, 8.7% CP), or 20% DDGS (excess CP, 11.6% CP). Cold acclimatization did not appear to affect nutrient intake and digestibility by beef cows, but increased N and P excretion by 1.2x and 2.5x, respectively. Cold acclimatized cows reduced energy excretion by 26.8% (7.1 vs. 5.2 ± 0.30% GEI in fall and winter, respectively; P < 0.0001) in accordance with a 33.8% increase in rumen fluid rate of passage (ROP). Supplementation with DDGS improved digestibility of N and P (40.6 vs. 61.2 ± 2.45% N and -23.9 vs. 5.7 ± 5.95% P for CON and 20%DDGS, respectively; P < 0.0001) by increasing digestible substrate in the diet. Protein supplementation increased rumen NH3-N concentrations (1.5, 2.1 and 3.1 ± 0.15 mg 100 mL-1; P < 0.0001) enough to increase rumen fermentation efficiency, resulting in 18.5% lower enteric CH4 emissions when CP was fed in excess of animal requirements. Total excretion of N and P were increased two- and 45-fold, respectively, when excess CP was fed. Reduced enteric CH4 emissions as a result of cold acclimatization suggest an advantage for the Canadian beef herd in terms of environmental sustainability. Supplementing CP in excess of cow requirements may improve nutrient utilization and rumen fermentation efficiency, and mitigate enteric CH4 emissions in beef cows fed low-quality forage diets, but may also contribute to greater N and P loading of soil and ground water.
54

Estudo das estruturas de membrana: uma abordagem integrada do sistema construtivo, do processo de projetar e dos métodos de análise / Study of membrane structures: an integrated approach of the constructive system, design process and analysis methods

Maria Betânia de Oliveira 10 April 2001 (has links)
As estruturas de membrana empregadas em coberturas são sistemas construtivos formados principalmente pela membrana estrutural, que ainda tem a função de vedar. As membranas estruturais são folhas flexíveis que resistem às ações externas devido à sua forma, às suas características físicas e ao seu pré tracionamento. O pré-tracionamento da membrana pode ser alcançado, ou através do seu estiramento por meio de cabos (estruturas de membrana protendida por cabos), ou através da atuação da pressão de gases (estruturas pneumáticas). Ambas estão sendo usadas em coberturas de centros esportivos, de áreas comerciais e de construções industriais ou agro-industriais. Todavia, as estruturas de membrana são pouco conhecidas, estudadas e empregadas no Brasil. Neste contexto, este trabalho tem como objetivos sistematizar o conhecimento científico existente sobre o tema e introduzi-lo no Brasil e, também, apontar caminhos para investigação científica sobre as estruturas de membrana no país. Apresenta o sistema construtivo, o processo de projetar e os métodos de análise das estruturas de membrana empregadas em coberturas. Sistematiza o projeto de estruturas de membrana, através de recomendações e de estudo de caso. Propõe um modelo de pesquisa integrado voltado para o desenvolvimento desta tecnologia no Brasil. Este deve auxiliar a coordenação e a compatibilização dos esforços de investigação científica nas diversas áreas do conhecimento envolvidas no desenvolvimento das estruturas de membrana / Membrane structures used in roofs are constructive systems formed mainly by structural membrane, which has also the function of sealing. Structural membranes are flexible sheets that resist to external loads due to their form, to their physical characteristics and to their pre-stressing. The pre-stressing of the membrane can be achieved either through its stretching using cables (surface-tensioned membranes) or through gases pressurization (pneumatic structures). These structures are being utilized in roofs over airports, stadiums, industrial facilities, shopping precincts and buildings for industrial or agricultural use, among others. However, membrane structures are not yet well known, studied and used here in Brazil. In this context, this work has as objectives to systematize the scientific knowledge existent on the theme, to introduce it in Brazil and, also, to point out ways for scientific investigation on membrane structures in this country. This research presents the constructive system, the design process and the analysis methods of membrane structures used in roofs. This work systematizes the membrane structural design, with recommendations and study of case. This work proposes an integrated model of research for this technology development in Brazil. This model should assist the coordination and the mutual appreciation of the scientific investigation efforts in the different knowledge areas involved in the membrane structure development
55

Mateřská škola / Kindergarten

de Ceita, Janet Klaudie January 2018 (has links)
The diploma thesis deals with elaboration of design documentation for the new building of the kindergarten. The building is divided into two parts. In the first part, two separate classes are designed, each with a capacity of 24 children, there are also teacher’s facilities, a logopedic counseling, and office. In the second part of the building there are classrooms for external activities. In the first part of the building, the kitchen is designed for the needs of the kindergarten. The building has two aboveground floors and a basement. Load-bearing walls are designed from SENDWIX, lime-cement bricks. Thermal insulation on walls above ground floor are a mineral wool and underground floor walls, as well as the plinth are insulated by extruded polystyrene XPS. The floors are made of pre-stressed concrete floor panels SPIROLL. The building has two types of roof: flat green roof and flat roof with stone aggregates. The drawing documentation necessary for the realization of the kindergarten is processed including five structural details. The drawing part was processed in the AutoCAD computer program. Part of the work is fire, acoustic, thermal-technical solution and daylighting.
56

Návrh přemostění komunikace / Design of the bridge structure across the street

Váša, Jiří January 2019 (has links)
The diploma thesis deals with the design of the motorway bridge over the II / 464 road between Butovice-Bílovec. For the bridging design four variants were made, from which a variant of the slab with longitudinal extensions was selected for further processing. The design assessment was performed for the ultimate limit state and serviceability limit state according to valid standards. Determination of internal forces was performed on the model developed in Scia Engineer 18.0.
57

Porovnání variant nádrže ČOV z železobetonu a z předpjatého betonu / Comparison of tank variants from reinforced concrete and prestressed concrete

Matuška, Vojtěch January 2020 (has links)
The diploma thesis deals with design and comparison of variants of cast-in-place concrete sewage tank made from reinforced concrete and pre-stressed concrete. The layout of sewage tank is rectangular. The tank is in longitudinal way divided into two chambers. The tank is not roofed and is partialy embedded in the ground. The design for ultimate limit state and for service limit state is made for both variants. There is focus on generation and development of cracks in service limit state. For calcuation of internal forces is used model made in software SCIA Engineer, based on finite element method. The reinforced concrete and pre-stressed concrete versions are compared in last part in term of volumes of materials needed. Also there are proposed possible savings.
58

Most přes potok Živný / Bridge over the Živný Brook

Sekanina, Josef January 2013 (has links)
This thesis occupies with the design of the road bridge over the stream Živný, a railway lane and a projected road between Běleč village and Husinec village. There are designed three variants of bridges. The variant no. 1 – continuous box girded beam – was chosen for the detailed analysis. The pre-stressed concrete road bridge is designed and evaluated according to European standards – Euro codes. The sequential construction influence and its impact on the construction is also considered in the calculations. The drawing documentation and the visualization of the bridge are made.
59

Lávka pro pěší přes rychlostní komunikaci / Footbridge across the expressway

Páleník, Petr January 2013 (has links)
The aim of this master thesis is a design of the pedestrian bridge across the highway. The bridge is formed by a slab structure of 6 spans with lenghts from 9 to 51 m. The main spans are suspended on a V shape pylon. The deck of the span across the highway is assambled of precast segments and composite deck slab. The deck is in the lenghtways kept in the parabolic arch. The model of the construction is made in software ANSYS, the solution was done non-linear. The design and assessment are according to the europien standard.
60

Zastřešení zimního stadionu / Ice Hockey stadium

Chalupa, Vojtěch January 2014 (has links)
The aim of this diploma thesis is the design of the roofing of an ice hockey stadium situated in Žďár nad Sázavou. Plan view dimensions are 55 m x 77 m. The structural height of the roof varies from 10 to 17 m. The roof itself consists of pipe truss girders with a span of 55 m, which are supported by columns on each side. The girders are suspended by a load-carrying arch with a span of 96 m and a camber of 29 m through a system of pre-stressed cables. To determine the internal forces, structural analysis software Scia Engineer was used. Individual elements were then manually designed.

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