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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.
191

Behaviour Of FRP Strengthened Masonry In Compression And Shear

Pavan, G S 03 1900 (has links) (PDF)
Masonry structures constitute a significant portion of building stock worldwide. Seismic performance of unreinforced masonry has been far from satisfactory. Masonry is purported to be a major source of hazard during earthquakes by reconnaissance surveys conducted aftermath of an earthquake. Reasons for the poor performance of masonry structures are more than one namely lack of deformational capacity, poor tensile strength & lack of earthquake resistance features coupled with poor quality control and large variation in strength of materials employed. Fibre Reinforced Plastic (FRP) composites have emerged as an efficient strengthening technique for reinforced concrete structures over the past two decades. Present thesis is focused towards analysing the behaviour of Fibre Reinforced Plastic (FRP) strengthened masonry under axial compression and in-plane shear loading. Determination of in-planes hear resistance of large masonry panels requires tremendous effort in terms of cost, labour and time. Masonry assemblages like prisms and triplets that represent the state of stress present in masonry walls and masonry in-fills when under the action of in-planes hear forces present an alternative option for research and analysis purposes. Hence, present research is focused towards analysing the performance of FRP strengthened masonry assemblages and unreinforced masonry assemblages. Chapter1 provides a brief review on the behaviour of masonry shear walls and masonry in-fills under the action of in-plane shear forces in addition to the performance of masonry structures during past earthquakes. Review of available literature on FRP confinement of masonry prisms with bed joints inclined from 00 to 900 to the loading axis under axial compression, analytical models available for FRP confined concrete, shear strength of masonry triplets attached with FRP is presented. Chapter 2 primarily focuses on determining the various properties of the materials involved in this research investigation. Test procedure and results of the tests conducted to determine the mechanical and related properties of the materials involved are presented. Elastic properties and stress-strain response of burnt clay brick, mortar and FRP laminates are presented. Studies conducted on behaviour of GFRP confined masonry prisms under monotonic axial compression are included in Chapter 3. The study comprised of testing masonry prisms, both unconfined and FRP confined masonry prisms under axial compression. Stretcher bond and English bond prisms, with bed joints normal and parallel to loading axis are included in this study. Two grades of GFRP,360g/m2 and 600 g/m2 are employed to confine masonry prisms. The experimental program involved masonry prism types that accounted for variations in masonry bonding pattern, bed joint inclination to the loading axis and grade of GFRP. Review of the available analytical models predicting compressive strength of FRP confined masonry prism is presented. Available models for FRP confinement of masonry are re-calibrated using the present experimental data generating new coefficients for the already existing model to develop new expression for predicting the compressive strength of FRP confined prisms. In addition to the prism types mentioned earlier, behaviour of unconfined and GFRP confined stretcher bond prisms with bed joints inclined at 300, 450 & 600 to the loading axis are further investigated. Chapter 4 primarily deals with the shear strength and deformational capacity of masonry triplets that represent joint shear failure in masonry. An experimental program involving masonry triplets attached with different types of FRP(GFRP and CFRP), grade of FRP, percentage area covered by FRP and reinforcement pattern is executed. This exercise determined the influence of these parameters over the enhancement achieved in terms of shear strength and ultimate displacement. Results of tests conducted on stretcher bond prisms presented in chapter 3 and results of tests on shear triplets presented in this chapter are combined to study the interaction between shear and normal stresses acting along the masonry bed joint at different angles of inclination. The thesis culminated with chapter 5 as concluding remarks highlighting the salient Information pertaining to the behaviour of FRP strengthened masonry under axial compression and in-plane shear loading obtained as an outcome of the research conducted as a part of this thesis.
192

Vápenné malty modifikované jemně mletým cihelným střepem / Lime Mortars Modified by Fine Ground Brick Body

Šmerdová, Ludmila January 2013 (has links)
Natural pozzolanic materials played an important role in Ancient architecture. In the last decades and nowadays it is artifical pozzolan which especially finds its use as an additive to mortar and concrete to improve some, especially the mechanical properties. This master thesis deals with study of pozzolan type of fine brick powder which is a by-product of the production of calibrated bricks. Along with studying pozzolanic activity of brick powder, lime mortar with different proportions of brick powder as an additive or replacement of lime dust are investigated. What is observed is its impact on the consistency of these mortar, water absorption, strength in time or fracture-mechanical parameters of mortar. The results may indicate the possible potential use of this source of pozzolanic admixture in lime mortar and plaster which are nowadays mainly used for the restoration of facades of historic buildings.
193

Optimalizace výrobního procesu / Optimization of production process

Nováková, Veronika January 2011 (has links)
The aims of this dissertation are to analyze the current state of process control, to identify the product range in selected organization and to design the process planning methodology to ensure an optimal implementation. Optimization is understood as costs minimization while keeping an acceptable continuity of supply. The dissertation contains a description of technological and non-manufacturing processes of brick products, as well as the summary and description of the basic tools of quality management.
194

Att skapa bilden av en sexualpolitisk pionjär : Anna Riwkins porträtt och reportagebilder av Elise Ottesen-Jensen 1938-1970 / To Create the Image of a Pioneer of Swedish Sexual Politics : Anna Riwkin’s portraits and reportage photographsof Elise Ottesen-Jensen 1938-1970

Ehne, Sandra January 2021 (has links)
Anna Riwkin fotograferade Elise Ottesen-Jensen i över tre decennier. Uppsatsens syftar till att reda på vad Riwkins fotografier av Ottesen-Jensen visar, hur de använts och hur Ottesen-Jensen tagit form som politisk aktör och subjekt genom dessa fotografier. Genom att undersöka ett material utvalt efter omfattande arkivsök, tidningssök och genomgång av litteratur har en bild av – och berättelse om – Ottesen-Jensen tagit form. Samarbetet med Riwkin har samtidigt synliggjorts och ett dubbelt aktörsskap trätt fram. Berättelsen om Ottesen-Jensen har strukturerats genom ett antal motivtyper som jag benämner talaren, lyssnaren, resenären, pedagogen och ordföranden. Uppsatsen synliggör hur den berättelsen tog form, mottogs i sin samtid, reproduceras och förändras idag. / Anna Riwkin photographed Elise Ottesen-Jensen over three consecutive decades. The aim of the thesis is to examine what Riwkin’s photographs of Ottesen-Jensen portray, how they have been used, and how Ottesen-Jensen is visually produced as a political subject through the same photographs. By examining a material selected through extensive research in personal-, magazine- and newspaper archives, exhibition catalogues and research, an image of – and story about – Ottesen-Jensen has taken shape. In the process, a collaboration and joint agency with Riwkin have materialized. The story about Ottesen-Jensen is presented through the suggested concepts of the talker, the listener, the traveler, the teacher, and the president. The thesis makes visible how that story was shaped and received, as well as how it is reproduced and evolving today.
195

Avaliação da suscetibilidade da alvenaria estrutural a danos por exposição a altas temperaturas com medidas de controle da dilatação

Menegon, Julia January 2017 (has links)
A alvenaria estrutural é um dos mais antigos sistemas construtivos existentes. Atualmente estruturas em alvenaria encontram uma vasta aplicação em construções residenciais, sobretudo em obras de interesse social. No entanto, ao contrário das estruturas de concreto, cujo comportamento durante exposição ao fogo e sua resistência residual tem estudos e resultados amplamente disseminados, pouco se sabe a respeito do comportamento de estruturas de alvenaria submetidas à ocorrência de sinistros dessa natureza. Com a intensificação das preocupações acerca da segurança das edificações e de seus usuários em situações de incêndio, faz-se cada vez mais imprescindível o conhecimento do comportamento dos sistemas empregados atualmente na construção civil perante a ação de altas temperaturas. Tendo isso em vista, o presente trabalho teve por objetivo a realização de uma análise dos danos e do comportamento apresentados por amostras de alvenaria com função estrutural ao serem expostas ao aquecimento excessivo. Foram avaliadas nesse estudo paredes de pequenas dimensões executadas com blocos estruturais cerâmicos. Visando simular condições mais próximas da realidade, foram restringidas, com o auxílio de macacos hidráulicos, as laterais das amostras, para que houvesse contenção da dilatação das mesmas. Com o intuito de verificar diferentes tipologias de alvenarias, foram utilizados três blocos distintos: de 14 cm de largura, com resistências de 7 e 10 MPa, e de 19 cm de largura, com 7 MPa de resistência à compressão. Também foram variadas as espessuras das juntas entre as unidades e a argamassa de assentamento das mesmas, a fim de compreender a importância desses fatores para o comportamento das amostras, e, por fim, foram ensaiadas amostras com revestimento na face exposta As miniparedes foram acopladas a um forno de resistências elétricas e submetidas a um aquecimento próximo à curva padrão determinada por norma, até a temperatura máxima de 950ºC, a qual foi mantida pelo período de 4 horas. Foram mensurados, além da temperatura dentro do forno, no interior da parede e na superfície das amostras, os deslocamentos transversais ocorridos durante o ensaio. Também se utilizaram transdutores de deslocamento para verificar a dilatação dos blocos e o esmagamento ou abertura das juntas. Imagens termográficas da face oposta ao aquecimento foram capturadas no decorrer da exposição. Ao final das análises, pôde-se inferir que as miniparedes ensaiadas apresentaram bom desempenho frente à ação das altas temperaturas, mantendo sua estanqueidade, isolamento térmico e resistência mecânica. A restrição lateral não ocasionou desplacamentos dos blocos, no entanto, pôde-se observar transferência de tensão para os mesmos quando utilizadas nas juntas argamassas pouco flexíveis. O deslocamento transversal apresentado pelas amostras indicou deflexão em direção ao forno durante o aquecimento, com posterior reversão do sentido. Tal deflexão foi atenuada pela redução da espessura das juntas, pelo uso de argamassas menos flexíveis e pelo aumento da resistência e largura dos blocos. As alvenarias de 19 cm de largura e, especialmente, as dotadas de revestimento apresentaram melhor desempenho térmico que as demais. / Structural masonry is one of the oldest existing building systems. Nowadays, masonry structures find a wide application in residential constructions, mainly in those with social interest. However, unlike concrete structures, whose behavior during fire exposure and its residual resistance have widely disseminated studies and results, there is a lack of knowledge about the behavior of masonry structures submitted to fire. Because of the spread of concerns about the safety of buildings and their users in fire situations, it becomes essential to know the behavior of the systems currently used in civil construction when exposed to high temperatures. With this in view, the present study intended to analyze the damage and the behavior of structural masonry samples exposed to heating. This study evaluated clay hollow-bricks small walls, and, in order to simulate real conditions, the boundaries of the samples were restrained, with the aid of hydraulic jacks, aiming to restrain the deformation. In order to verify different types of masonry, three different blocks were used: 14 cm wide, with nominal strength of 7 and 10 MPa, and 19 cm wide, with 7 MPa of compressive strength. The thicknesses of the joints and the mortar were also varied, in order to understand the importance of these factors in the behavior of the samples, and, finally, samples were tested with a mono-layer coating at the exposed face. The small walls were coupled to an electrical furnace and subjected to a heating approximately equal to the standard curve, up to the maximum temperature of 950ºC, which was maintained for 4 hours The deflections of the samples during the test were measured, beyond the temperature inside the furnace, in the center of wall and at the non-exposed surface. Clip gages were also used to verify the expansion of the blocks and the crushing or opening of the mortar joints. Thermographic images of the opposite face were captured during the testing. At the end of this research, it was possible to affirm that the walls had good behavior against the high temperatures, maintaining their integrity, thermal insulation and load-bearing capacity. The restriction of the boundaries did not cause the spalling of the blocks, however, it was possible to observe the stress transfer to them in samples with rigid joint mortar. The deflection of the samples increases towards the furnace during the heating, and, then, they show the phenomenon of “reverse bowing”, changing the direction of the displacements. Reducing the thickness and increasing the stiffness of the joint mortars, as well as the increase in block strength and width attenuated such deflection. The masonry 19 cm width and, specially, the ones with coating shows better thermal performance, comparing to the others.
196

Estudo do efeito do não preenchimento das juntas verticais e eficiência do graute na resistência da alvenaria estrutural de blocos cerâmicos / Study of the effect of unfilled vertical joints and efficiency of grout in the strength of structural masonry of clay bricks

Miranda, Larissa de Almeida 31 October 2012 (has links)
No contexto do crescimento do processo construtivo em alvenaria estrutural, destaca-se o uso do bloco cerâmico consolidado com a criação de sua norma específica de projeto, execução e controle de obras, a NBR 15812, partes 1 e 2 (ABNT, 2010). Desde a difusão da alvenaria estrutural, mudanças nas técnicas construtivas vêm ocorrendo, como por exemplo, o não preenchimento das juntas verticais de assentamento dos blocos. Outra prática que tem sido utilizada é o grauteamento da alvenaria. No entanto, ainda não está estabelecido se o não preenchimento da junta vertical compromete o desempenho da alvenaria ou qual a resistência necessária ao graute para aumentar a resistência da alvenaria. Diante disto, o trabalho objetiva contribuir com o estudo do não preenchimento das juntas verticais avaliando o seu efeito na resistência à compressão e ao cisalhamento de pequenas paredes e também pesquisar a influência do graute em prismas e pequenas paredes submetidos à compressão. Com as análises dos resultados pode-se concluir que o não preenchimento das juntas verticais não exerceu influência nos valores de resistência à compressão e também nos módulos de elasticidade longitudinal das pequenas paredes ensaiadas. No entanto, influenciou significativamente os resultados do ensaio de compressão diagonal para avaliar a resistência ao cisalhamento, apesar do módulo de deformação transversal ter sido considerado equivalente. Os resultados do estudo preliminar em prismas mostraram que a média da resistência à compressão em relação à área bruta do prisma grauteado, utilizando o Graute A e o Graute C, foi equivalente à média do prisma oco. Assim, foi escolhido o Graute A para a confecção de pequenas paredes e prismas. Pode-se concluir com os resultados das pequenas paredes grauteadas que houve um aumento significativo da resistência à compressão em relação à área bruta, mas em relação à área líquida, os valores encontrados foram equivalentes às pequenas paredes ocas. Portanto o aumento na resistência à compressão na pequena parede foi proporcional ao ganho de área dado pelo grauteamento de seus vazios, diferentemente do comportamento observado nos prismas. / In the context of growth of structural masonry construction process, it highlight the use of the ceramic block consolidated with the creation of its specific standard of design, execution and control, the NBR 15812, Parts 1 and 2 (ABNT, 2010). Since the propagation of structural masonry, changes have occurred in the construction techniques, such as don\'t fill the vertical joints of the masonry wall. Another technique that has been used is the grouted masonry. However, it is not yet established if the unfilled vertical joints compromise the performance of masonry or which strength is necessary to the grout to increase the strength of the masonry. Therewith, the paper aims to contribute to the study of unfilled vertical joints by analyzing its effect on compressive strength and shear strength of small walls and also investigate the influence of grout in prisms and small walls under compression. With the analysis of the results we can conclude that do not fill the vertical joints had no influence on the values of compressive strength and elastic modulus of the small walls tested. However, it significantly affects the results of the diagonal compression test to evaluate shear strength, despite the shear elastic modulus being considered equivalent. The results of the preliminary study in prisms showed that the average of the compressive strength in relation to the gross area of the grouted prism using the Grout A and the Grout C were equivalent to the average of hollow prism. Thus, small walls and prisms with the Grout A were made. It can be concluded with the results of grouted small walls that there was a significant increase in compressive strength with respect to the gross area, but in relation to the net area, were similar to the hollow small wall. Therefore the increase in the compressive strength in a small wall is proportional to the gain of the area given by the grout, unlike the behavior observed in the prisms.
197

An investigation into the non-adoption of soil-cement bricks by the community of the Kei District

Williams, Nomsa January 2002 (has links)
Thesis (M. Dev.) -- University of Limpopo, 2002 / Refer to document
198

多元數位選擇權-天天對獎

郭雅芸, Kuo, Ya-Yun Unknown Date (has links)
由於現今市場上的新金融商品種類仍不能滿足各種避險者的需要,鑒於台灣目前仍沒有數位選擇權(digital option)的相關產品,且數位選擇權能為避險者減低避險成本的特性是值得被重視的,因此本論文對於另一個新奇選擇權:C-Brick進行較詳細的討論與實證分析。C-Brick是數位選擇權的一種,C-Brick有兩個標的資產,是一個多元數位選擇權,它能提供給擁有兩檔標的股票的投資者較低成本的避險管道。 本文將對C-Brick的價格行為、特質做進一步的研究,討論股價、波動度、相關係數等與C-Brick價格的關係。另外對delta做更詳細的分析。 在實證分析方面,利用建構避險部位的方式對C-Brick進行避險績效的分析,以聯電與台積電、南亞與台塑、合發與台積電為例子進行分析。為了探討避險績效之優劣本文將股價走勢分為上升、盤整、下降等三類探討股價變動對於避險績效的影響。同時也探討波動度對避險績效之關係。 最後,我們將C-Brick做較不同的變化:同時發行數個不同到期日、不同履約價的C-Brick,這樣除了讓這項商品更具吸引力外,我們也對此發行方法在避險考量上,做了可行與否的討論。
199

Evaluation Of Seismic Resistance Of Traditional Ottoman Timber Frame Houses

Aktas, Yasemin Didem 01 August 2011 (has links) (PDF)
The aim of this study is to evaluate the seismic resistance of traditional Ottoman timber frame &ldquo / himis&rdquo / structures, which form the major part of Turkey&rsquo / s cultural heritage, from an engineering point of view. On the other hand, the seismic resistance of traditional Ottoman timber frame structures was not evaluated from an engineering perspective. For the aim of seismic resistance evaluation of traditional Ottoman timber frame houses, the TUBITAK (the Scientific and Technological Research Council of Turkey) project numbered 106M499 was carried out. Within this framework, 16 tests were carried out in the Structural Mechanics Laboratory of Middle East Technical University, by means of 8 1-1 scale timber frames of different geometrical configurations and material, carefully selected from traditional houses in Safranbolu, representing Ottoman timber frame &ldquo / himis&rdquo / technique. The frames were tested without and with different infill/covering types, and parameters that directly or indirectly indicate the behavior of a structure under earthquake loading were derived from the results obtained at the end of experimental work. In addition, capacity calculations were carried out for each test, using ATC-40 procedure. The results demonstrated that Ottoman timber frame &ldquo / himis&rdquo / houses are seismically resistant, and yet there are a number of important points that should be obeyed in their construction regarding size of diagonal elements, size and placement of openings, intervals between vertical studs, as well as connection details. It is also seen that certain infill/covering materials/methods are more advantageous than the others / for example, covering techniques results in a higher amount of maximum lateral load that the frame can bear under the same displacement. Infill with masonry blocks results in a larger increase in weight than in load bearing capacity. The conclusions drawn are intended to be used not only in the conservation of such structures but they are also expected to direct modern seismically resistant constructions.
200

Sustainability in Retailing – Environmental Effects of Transport Processes, Shopping Trips and Related Consumer Behaviour

Wiese, Anne 16 August 2013 (has links)
No description available.

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