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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

Características das fibras do bambu (Dendrocalamus giganteus) e potencial de aplicação em painéis de fibra de média densidade (MDF)

Marinho, Nelson Potenciano 18 May 2012 (has links)
O aumento da demanda por madeira e a redução da sua disponibilidade tem direcionado investigações para o aproveitamento de materiais alternativos, naturais e renováveis. Constituído por fibras de elevada resistência mecânica e uma das maiores taxas de crescimento, o bambu surge como uma alternativa promissora para o uso industrial. Os painéis de fibra de média densidade (MDF - Medium Density Fiberboard) são tecnologias recentes que procuram maximizar o aproveitamento e valorização das madeiras. Neste contexto, a presente pesquisa teve como objetivo investigar as características anatômicas e químicas das fibras do bambu da espécie Dendrocalamus giganteus e, na forma de painéis de MDF, avaliar as suas propriedades físico-mecânicas como: densidade, teor de umidade, inchamento em espessura, absorção de água, flexão estática e a tração perpendicular à superfície, segundo as normas ABNT e EN. A composição química foi obtida por meio de análises em EDS (Energy Dispersive X-Ray Spectroscopy) e visualizada suas concentrações por meio de imagens do Microscópio Eletrônico de Varredura (MEV) sendo o principal elemento o silício. Para a produção das fibras foi empregado o método quimotermomecânico com 4 diferentes tipos de tratamentos, a fim de compará-los entre si. Na composição dos painéis foi utilizada a resina Uréia Formaldeído (UF) em percentuais de 10%, com 2,5% de catalisador e 2% de parafina. O maior rendimento bruto de polpação e o número Kappa mais alto foram encontrados no painel T-1 com 79.3% e 177.5, respectivamente. Nas avaliações das propriedades físico-mecânicas os resultados das análises estatísticas indicaram as melhores relações de desempenho com o painel T-3. Para a melhor compreensão do comportamento mecânico foram realizadas análises micrográficas em MEV e Microtomografia nas regiões de fraturas. As análises térmicas (TG) apresentaram fibras resistentes com estabilidade térmica em faixa de temperatura de até 350ºC. Os resultados desta pesquisa apontam para um potencial tecnológico de painéis de MDF produzidos a partir das fibras do bambu, desde que tenham os processos apropriados. / The increased demand for wood and the reduce on its availability is directing the investigations for alternative, natural and renewable materials use. Formed by fibers with high mechanical resistance and with the highest grow rate, bamboo emerges as a promising alternative for industrial purpose. The panels of medium density fiberboard (MDF) are technologies that aim to maximize use and appreciation of wood. In this context this study had the objective of investigate anatomical and chemical characteristics of bamboo fiber from Dendrocalamus giganteus, and in form of MDF panel, evaluate its physical-mechanical properties, such density, moisture content, thickness swelling, water absorption static bending and tension perpendicular to surface, according with ABTN and EN rules. The chemical composition was evaluated by Energy Dispersive X-Ray Spectroscopy (EDS) and illustrated by Scanning Electron Microscope (SEM) being the silicon the main component. For fiber production was applied chemical-termomechanical process with four different treatments with the objective of compare it. In panel composition was used Urea Formaldehyde resin (UF) in 10% of resin, 2.5% of catalyst and 2% of paraffin. The highest yield of pulp and highest Kappa number were obtained on panel T-1 with 79.3% and 177.5, respectively. On physical and mechanical properties evaluation, the results of statistical analysis indicate the best performance in T-3 panel. For better comprehension of mechanical behavior, scanning electron microphotography and microtomography in fracture regions were obtained. Thermal analyses (TG) showed resistant fibers with thermal stability in temperature range up 350ºC. The results of this research showed the technological potential of MDF panels produced with bamboo fibers.
32

Características das fibras do bambu (Dendrocalamus giganteus) e potencial de aplicação em painéis de fibra de média densidade (MDF)

Marinho, Nelson Potenciano 18 May 2012 (has links)
O aumento da demanda por madeira e a redução da sua disponibilidade tem direcionado investigações para o aproveitamento de materiais alternativos, naturais e renováveis. Constituído por fibras de elevada resistência mecânica e uma das maiores taxas de crescimento, o bambu surge como uma alternativa promissora para o uso industrial. Os painéis de fibra de média densidade (MDF - Medium Density Fiberboard) são tecnologias recentes que procuram maximizar o aproveitamento e valorização das madeiras. Neste contexto, a presente pesquisa teve como objetivo investigar as características anatômicas e químicas das fibras do bambu da espécie Dendrocalamus giganteus e, na forma de painéis de MDF, avaliar as suas propriedades físico-mecânicas como: densidade, teor de umidade, inchamento em espessura, absorção de água, flexão estática e a tração perpendicular à superfície, segundo as normas ABNT e EN. A composição química foi obtida por meio de análises em EDS (Energy Dispersive X-Ray Spectroscopy) e visualizada suas concentrações por meio de imagens do Microscópio Eletrônico de Varredura (MEV) sendo o principal elemento o silício. Para a produção das fibras foi empregado o método quimotermomecânico com 4 diferentes tipos de tratamentos, a fim de compará-los entre si. Na composição dos painéis foi utilizada a resina Uréia Formaldeído (UF) em percentuais de 10%, com 2,5% de catalisador e 2% de parafina. O maior rendimento bruto de polpação e o número Kappa mais alto foram encontrados no painel T-1 com 79.3% e 177.5, respectivamente. Nas avaliações das propriedades físico-mecânicas os resultados das análises estatísticas indicaram as melhores relações de desempenho com o painel T-3. Para a melhor compreensão do comportamento mecânico foram realizadas análises micrográficas em MEV e Microtomografia nas regiões de fraturas. As análises térmicas (TG) apresentaram fibras resistentes com estabilidade térmica em faixa de temperatura de até 350ºC. Os resultados desta pesquisa apontam para um potencial tecnológico de painéis de MDF produzidos a partir das fibras do bambu, desde que tenham os processos apropriados. / The increased demand for wood and the reduce on its availability is directing the investigations for alternative, natural and renewable materials use. Formed by fibers with high mechanical resistance and with the highest grow rate, bamboo emerges as a promising alternative for industrial purpose. The panels of medium density fiberboard (MDF) are technologies that aim to maximize use and appreciation of wood. In this context this study had the objective of investigate anatomical and chemical characteristics of bamboo fiber from Dendrocalamus giganteus, and in form of MDF panel, evaluate its physical-mechanical properties, such density, moisture content, thickness swelling, water absorption static bending and tension perpendicular to surface, according with ABTN and EN rules. The chemical composition was evaluated by Energy Dispersive X-Ray Spectroscopy (EDS) and illustrated by Scanning Electron Microscope (SEM) being the silicon the main component. For fiber production was applied chemical-termomechanical process with four different treatments with the objective of compare it. In panel composition was used Urea Formaldehyde resin (UF) in 10% of resin, 2.5% of catalyst and 2% of paraffin. The highest yield of pulp and highest Kappa number were obtained on panel T-1 with 79.3% and 177.5, respectively. On physical and mechanical properties evaluation, the results of statistical analysis indicate the best performance in T-3 panel. For better comprehension of mechanical behavior, scanning electron microphotography and microtomography in fracture regions were obtained. Thermal analyses (TG) showed resistant fibers with thermal stability in temperature range up 350ºC. The results of this research showed the technological potential of MDF panels produced with bamboo fibers.
33

Analysis and Design of Wood Construction Platforms Using Instrumentation

Stroble, Martin Feeney 11 December 2009 (has links)
Wood construction platforms are a common method for inexpensive, temporary soil stabilization under heavy machinery; however, platforms are not typically thought of as an engineered product. Review of literature has shown that only one design method is currently available and is specific to one type of platform configuration. The purpose of this thesis is to develop a design method that is simple, versatile and accurate. The proposed design method was intentionally developed so that the designer would have input in multiple areas of the design. Instrumentation allowed for increased insight into the mechanical behavior of the platforms. The objective of this research is to use measured strain, load, and deflection in conjunction with fundamental engineering mechanics principles to predict a single platform’s mechanical behavior on the ground. Results from this method compare favorably with the only other design guide available and improves the knowledge base by developing design guidance for any type of wood construction platform.
34

The economic feasibility of producing yellow-poplar oriented strandboard in the Appalachian region

Brown, Lisa Ann January 1983 (has links)
This study has been conducted in order to determine whether yellow-poplar (Liriodendron tulipifera Michx.), has the economic and technical potential to be manufactured and marketed as oriented strandboard (OSB) in Elkins, West Virginia and Frederick, Maryland. The estimated annual excess growth of yellow-poplar near Elkins could provide more than enough timber to supply a 120 MMSF OSB facility (3/8-inch basis); however, the estimated annual excess growth of yellow-poplar available near Frederick is insufficient to provide the total wood requirement for a facility of this size. Yellow-poplar is a relatively low density species, and is suitable for the production of OSB. The manufacture of yellow-poplar OSB is viable, employing commercially available technology. OSB is a suitable substitute for softwood plywood sheathing. The panel markets within radii of approximately 300 miles of both Elkins, West Virginia and Frederick, Maryland are sufficient to support the addition of a 120 MMSF OSB facility at either location. Equipment and operating requirements and costs have been estimated for 1982. Using a USDA Forest Service computer program, EVALUE, an internal rate of return on investment (IRR) of 15.2 percent was calculated for Elkins, and 14.3 percent for Frederick. The sensitivity of facility productivity to an increase of 10 percent in the cost of wood, and resin, and to a 10 percent decrease in the price of panels has also been calculated. / M.S.
35

Análise de elementos estruturais de MLC na flexão com base na versão de revisão da norma ABNT NBR 7190:2013 /

Gomes, Nádia Barros. January 2018 (has links)
Orientador: Julio Cesar Molina / Banca: Cristian Inácio de Campos / Banca: André Luis Christoforo / Resumo: O objetivo desta pesquisa consistiu na avaliação do modelo de cálculo proposto pela versão de revisão da Norma Brasileira de Estruturas de Madeira ABNT NBR 7190:2013 para avaliação do comportamento de elementos de MLC na flexão. Foram considerados elementos de MLC com dimensões padronizadas de 5 x 5 x 115 cm para realização dos ensaios experimentais de flexão, tendo-se em vista a da rigidez (EI) para posterior comparação com os resultados numéricos e teóricos. Foram avaliados, também neste caso, os modos de ruptura apresentados nos ensaios experimentais por cada sistema. Na confecção dos elementos de MLC foram utilizadas madeiras de reflorestamento de pinus e eucalipto da região de Itapeva - SP coladas com resina resorcinol formaldeído. Todas as lâminas de madeira passaram por processo de classificação mecânica e visual. As simulações numéricas foram realizadas no software ANSYS, que tem como base o método dos elementos finitos e estas serviram para a avaliação das distribuições das tensões nas regiões de interesse dos elementos de MLC. Os ensaios experimentais de flexão e de caracterização dos materiais foram no Laboratório de Propriedades dos Materiais da UNESP/Itapeva a partir da utilização da Máquina Universal de Ensaios EMIC com capacidade de 300 KN. Como resultado, observou-se que o modelo teórico proposto pela ABNT NBR 7190:2013 mostrou, para este trabalho, maior aproximação com os resultados experimentais e numéricos para as madeiras de pinus. Além disso, os modos de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this work was to evaluate the calculation model proposed by the revision version of the ABNT NBR 7190: 2013 Wood Structures Brazilian Standard to evaluate the behavior of Glued Laminated Timber in bending. Glulam elements with standard dimensions of 5 x 5 x 115 cm were considered to perform the experimental bending tests considering the stiffness (EI) for later comparison with numerical and theoretical results of EI. The failure modes presented in the experimental tests by each system were also evaluated. In the preparation of the glulam elements, pine and eucalyptus reforestation woods from the Itapeva - SP region were glued with resorcinol formaldehyde resin. All the wood layers were classified by mechanical and visual process. The numerical simulations were performed in the ANSYS software, which is based on the finite element method and these were used to evaluate the stress distributions in the areas of interest of the glulam elements. Experimental bending tests and material characterization tests were performed at the Materials Properties Laboratory of UNESP / Itapeva using the Universal Testing Machine - EMIC with a capacity of 300 KN. As a result, it was observed that the theoretical model proposed by ABNT NBR 7190: 2013 standard showed, for this work, greater approximation with the experimental and numerical results for pine woods. In addition, the failure modes obtained theoretically were verified for the experimental and numerical analyzes performed / Mestre
36

Technické muzeum v Olomouci / The technical museum in Olomouc

Gelová, Michaela January 2018 (has links)
This diploma thesis deals with the design of the structure of the multi-storey building of the Technical Museum in Olomouc. This timber structure is made of glued laminated wood with the strenghts Gl24h and Gl32h. It is a complex of six adjoining buildings, which are shifted from one another in both transverse direction and the heigth. The ground plan dimensions of the parcel on which tha hal lis decomposed is 40 x 80 m. A complete static design solution, including its foundation, anchoring and selected type connections, has been solved.
37

Razvoj hibridnog modela za ocenjivanje životnog ciklusa proizvoda i procesa / Development of the hybrid model for life cycle assessment of products and processes

Milanović Branislav 11 July 2016 (has links)
<p>U okviru doktorske disertacije predstavljen je<br />razvoj hibridnog modela za ocenjivanje životnog ciklusa<br />proizvoda i procesa. Razvoj hibridnog modela se ogleda<br />kroz unapređenje postojećeg metodskog okvira LCA, te je<br />stoga uključio razvoj svih faza LCA, a koje obuhvataju<br />definisanje cilja i predmeta, inventar životnog ciklusa,<br />ocenjivanje uticaja životnog ciklusa i interpretaciju<br />rezultata. Najznačajnija unapređenja su sprovedena u<br />okviru faza inventara životnog ciklusa i ocenjivanja uticaja<br />životnog ciklusa. Izmene koje se odnose na način<br />prikupljanja podataka, su razvijene zbog uključivanja<br />parametara potrebnih za izračunavanje vrednosti sadržaja<br />eksergije tokova. Unapređenje faze ocenjivanja uticaja<br />životnog ciklusa se ogleda kroz razvoj originalnog pristupa<br />za izračunavanje ukupne potro&scaron;nje eksergije, kroz<br />uključivanje dodatne kategorije uticaja, razvijanje<br />indikatora kategorije uticaja i razvijanje pristupa za<br />izračunavanje karakterizacionih faktora. Sprovedena je i<br />analiza postojećih LCIA metoda, radi izbora adekvatnog<br />metoda u koji će biti uključena dodatna kategorija uticaja,<br />kao i indikator kategorije uticaja, koji zajedno opisuju<br />ukupnu potro&scaron;nju eksergije tokom čitavog životnog<br />ciklusa. Takođe, prilikom razvoja kategorije uticaja su<br />po&scaron;tovani određeni kriterijumi, koje ona mora da zadovolji<br />da bi mogla biti adekvatno uključena u odabrani LCIA<br />metod. Pored toga, bitan deo unapređenja ocenjivanja<br />uticaja životnog ciklusa, leži u razvoju proračuna<br />karakterizacionih faktora. Razvijena dodatna kategorija<br />uticaja nazvana je Ukupna potro&scaron;nja eksergije - UPE, a<br />izražava se preko indikatora MJex. LCIA metod koji je<br />odabran na osnovu SWOT analize u koji je ova dodatna<br />kategorija uticaja uključena je CML metod. Postavljeni<br />hibridni metodski okvir posmatra kompletan životni ciklus,<br />ali i svaki od jediničnih procesa koji uključuju elementarne<br />tokove, odnosno tokove uzete iz prirodnog sistema bez<br />dodatne obrade, kao i tokove proizvoda, odnosno tokovekoji su na neki način izmenjeni od strane pojedinih<br />antropogenih sistema. Izračunavanje sadržaja eksergije i<br />karakterizacionih faktora je sprovedeno kako za<br />elementarne tokove tako i za tokove proizvoda.<br />Funkcionalnost i praktična primenljivost razvijenog<br />hibridnog modela je verifikovana na dva primera, koji su<br />obuvatili proizvodnju laminatnog parketa i međusobnu<br />komparaciju hibridnih baznih predajničkih stanica i<br />konvencionalnih baznih predajničkih stanica. Dobijeni<br />rezultati daju jednu zaista detaljniju i &scaron;iru sliku mehanizma<br />nastanka i izvora negativnih uticaja tokom životnog ciklusa<br />posmatranih industrijskih sistema. Time je potvrđena<br />njegovu praktična primenljivost, kao i ukupni cilj<br />istraživanja. Rezultati istraživanja realizovani u okviru<br />doktorske disertacije, u op&scaron;tem smislu, daju doprinos<br />stvaranju osnove za izdradnju puta ka razvoju i proizvodnji<br />održivih proizvoda i procesa. Razvijeni hibridni model za<br />ocenjivanje životnog ciklusa proizvoda i procesa pruža<br />dodatne informacije, koje mogu biti korisne u procesu<br />dono&scaron;enja odluka na svim nivoima, kako u industriji tako i<br />u državnim institucijama.</p> / <p>This PhD thesis presented the development of a<br />hybrid model for life cycle assessment of products and<br />processes. The development of a hybrid model includes the<br />improvement of the existing methodological LCA<br />framework, and therefore of all phases of the LCA:<br />definition of goal and scope, inventory analysis, life cycle<br />impact assessment and interpretation. The most significant<br />improvements have been made within the inventory<br />analysis and life cycle impact assessment phases.<br />Improvement have been made in relation to the method of<br />data collection, due to the inclusion of parameters for<br />calculation of the exergy content of in- and output flows.<br />Improvement of the life cycle impact assessment phase is<br />reflected through the development of original approach for<br />calculating the total consumption of exergy, through the<br />inclusion of additional impact category, development of<br />indicator for impact category and development of method<br />for calculation of characterization factors. The analysis of<br />existing LCIA methods was performed, in order to choose<br />the appropriate method that will incorporate this additional<br />impact category, as well as an impact category indicator,<br />which together should describe the total consumption of<br />exergy throughout the entire life cycle. Further,<br />development of this impact category have been complied<br />with certain criteria which it must meet in order to be<br />properly incorporated in the chosen LCIA method. Besides<br />this, an important part of improvement of the life cycle<br />impact assessment is the development of method for<br />calculation of characterization factors. Developed<br />additional impact category is named Total exergy<br />consumption, and it&#39;s expressed through indicator of MJex.<br />LCIA method that is chosen based on the performed<br />SWOT analysis and which incorporated this additional<br />impact category is CML method. Developed hybrid<br />methodological framework takes into account the entire life<br />cycle, and each of the unit processes that involves<br />elementary flows (flows taken from the natural system<br />without any further processing), as well as product flows(flows that are in some way altered by certain<br />anthropogenic system). Calculation of exergy and<br />characterization factors was performed for both elementary<br />and product flows.<br />Functionality and practical applicability of the<br />developed hybrid model was verified through two case<br />studies, which are the production of laminate parquet<br />flooring and comparison of hybrid base transceiver stations<br />and conventional base transceiver stations. The obtained<br />results provided more detailed and more broader insight of<br />the mechanism of the generation and source of negative<br />impacts throughout the life cycle of observed industrial<br />systems. Thus, the practical applicability of the developed<br />hybrid model and goal of the research have been<br />confirmed. The results of the research contribute to<br />creation of the foundation for designing a path towards<br />development and manufacturing of sustainable products<br />and processes. The developed hybrid model for the life<br />cycle assessment of products and processes provides<br />additional information that may be useful in decisionmaking<br />process at all levels, within both industry and<br />government institutions.</p>
38

Přístřešek v areálu parku / Shelter in park

Svršek, Josef January 2020 (has links)
This diploma thesis deals with design of the structure of the shelter i the park of city Hranice na Moravě. This load-bearing structure is made of glued laminated wood with the strength class GL24h. The structure has the shape of half ball and the load-bearing beams are in the shape of an arc. This building will be mainly used for cultural purposes. Ground plan dimensions of this shelter are 25x25 m. A complete static design solution including of all connection details and anchoring has been solved.
39

Výukové a vzdělávací centrum / Training and Education Centre

Halla, Antonín January 2013 (has links)
This thesis solves design and project of construction of training and education centre, contains library, classrooms and administratice facilities. The building is set into a former allotment gardens on outskirt of Brno. The project reclaimed this land. The shape of the bulding is created by two connected curves, it reminds wide open letter "U". There are two buildings connected with glass vestibule, the object is partially sunk below ground. South side of the building consists of a double transparent facade, which contributes to energy savings, the northern facade is clad with wooden battens. Underground constructions are made of concrete, pillars and horizotal structures are made of laminated wood. Green roof is transferred underground on the west and east side of building. In the interior alternates exposed concrete and laminated wood.
40

Sportovní centrum Fit4You / Sports Center Fit4You

Záleský, Radek January 2014 (has links)
This master‘s thesis deals with the design documentation Fit4You sports center. The new building is located in the district of the City of Brno in the cadastral Brno – Líšeň. The building is designed as a reinforced concrete skeleton system with ceramic masonry infill with two floors. Part of the building with the sports hall is roofed with arched trusses made of laminated wood. The second part of the building with facilities for the hall is roofed with a flat floor.

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