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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.
1

Techniques for automated visual inspection of birch wood boards

Alcock, Robert J. January 1996 (has links)
No description available.
2

Resistência mecânica do material compósito: madeira de eucalipto-lâmina de bambu

Ostapiv, Fabiano [UNESP] 03 June 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-06-03Bitstream added on 2014-06-13T20:04:26Z : No. of bitstreams: 1 ostapiv_f_dr_guara.pdf: 5560397 bytes, checksum: 47aba74cdd214f3da2d1bf29d8bc1ff8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Tanto o bambu como o eucalipto são importantes recursos florestais. As lâminas de bambu gigante, contínuas, largas e finas obtidas por processo de torneamento são um excelente material para revestir e reforçar madeira e painéis sarrafeados de eucalipto. Neste trabalho foram realizados ensaios de cisalhamento e tração normal na madeira de eucalipto de alta densidade com e sem o revestimento com lâminas de bambu. Foram produzidos painéis sarrafeados colados lateralmente (EGPs) de Eucalyptus saligna que foram ensaiados à flexão estática e a tração normal, segundo a norma NP EN 310, no sentido transversal do painel em que as ripas são coladas lateralmente. Verificou-se que as lâminas de bambu funcionaram como reforço mecânico para os casos de tração normal na madeira de eucalipto, mas que não houve reforço quando sujeita a esforços cisalhantes, independentemente da posição dos anéis de crescimento da madeira nas amostras. Neste caso as lâminas funcionaram apenas como revestimento. Verificou-se um comportamento frágil do painel sarrafeado de eucalipto durante sua ruptura a flexão no sentido transversal. Foram repetidos os ensaios para os painéis sarrafeados de eucalipto revestidos com lâminas de bambu gigante em dupla face. Verificou-se então um grande aumento na resistência mecânica à flexão estática no painel laminado. Com o reforço das lâminas houve uma mudança no comportamento do painel que deixou de romper de forma frágil passando a romper de modo dúctil, tornando o painel mais elástico e confiável ao uso. Além disso, foram estudadas as características de acabamento superficial das lâminas de bambu quando o material é submetido a processos de lixamento manual / Both bamboo and eucalyptus wood are important forest resources. The giant bamboo veneers continuous, wide and thin obtained by turning process are an excellent material for cover and reinforce the wood and laths edged glued panels (EGP) of Eucalyptus saligna. In this work was tested the eucalyptus wood of high density to shear and normal traction, then the eucaliptus wood was covered with layers of bamboo veneer and so repeated the same mechanic tests. Were produced panels EGP of eucalyptus that were tested for static bending, according to NP EN 310, in the direction that the laths are glued. It was found that bamboo veneers acted as mechanical reinforcement for the cases of normal traction in the eucalyptus wood, but there was no increase in eucalyptus wood subjected to shear efforts, regardless of the position of growth rings in wood samples. In this case the veneers functioned only as a coating. There was a fragile behavior of the panel EGP of eucalyptus during their break to shear efforts. The tests were repeated for the panels EGP coated with bamboo venners on double-sided. There was then a large increase in mechanical resistance to bending of laminated panel. With the increase obtained was a change in behavior of the panel that failed through the fragile break so ductile rupture, making the panel more elastic and reliable to use. Furthermore were studied the characteristics of roughness of the surface of bamboo veneer when the material is subjected to manual sanding processes
3

Resistência mecânica do material compósito : madeira de eucalipto-lâmina de bambu /

Ostapiv, Fabiano. January 2011 (has links)
Orientador: Marcos Tadeu Tibúrcio Gonçalves / Banca: Manoel Cléber de Sampaio Alves / Banca: Marcos Valério Ribeiro / Banca: Eduardo Mauro do Nascimento / Banca: Ivaldo de Domênico Valarelli / Resumo: Tanto o bambu como o eucalipto são importantes recursos florestais. As lâminas de bambu gigante, contínuas, largas e finas obtidas por processo de torneamento são um excelente material para revestir e reforçar madeira e painéis sarrafeados de eucalipto. Neste trabalho foram realizados ensaios de cisalhamento e tração normal na madeira de eucalipto de alta densidade com e sem o revestimento com lâminas de bambu. Foram produzidos painéis sarrafeados colados lateralmente (EGPs) de Eucalyptus saligna que foram ensaiados à flexão estática e a tração normal, segundo a norma NP EN 310, no sentido transversal do painel em que as ripas são coladas lateralmente. Verificou-se que as lâminas de bambu funcionaram como reforço mecânico para os casos de tração normal na madeira de eucalipto, mas que não houve reforço quando sujeita a esforços cisalhantes, independentemente da posição dos anéis de crescimento da madeira nas amostras. Neste caso as lâminas funcionaram apenas como revestimento. Verificou-se um comportamento frágil do painel sarrafeado de eucalipto durante sua ruptura a flexão no sentido transversal. Foram repetidos os ensaios para os painéis sarrafeados de eucalipto revestidos com lâminas de bambu gigante em dupla face. Verificou-se então um grande aumento na resistência mecânica à flexão estática no painel laminado. Com o reforço das lâminas houve uma mudança no comportamento do painel que deixou de romper de forma frágil passando a romper de modo dúctil, tornando o painel mais elástico e confiável ao uso. Além disso, foram estudadas as características de acabamento superficial das lâminas de bambu quando o material é submetido a processos de lixamento manual / Abstract: Both bamboo and eucalyptus wood are important forest resources. The giant bamboo veneers continuous, wide and thin obtained by turning process are an excellent material for cover and reinforce the wood and laths edged glued panels (EGP) of Eucalyptus saligna. In this work was tested the eucalyptus wood of high density to shear and normal traction, then the eucaliptus wood was covered with layers of bamboo veneer and so repeated the same mechanic tests. Were produced panels EGP of eucalyptus that were tested for static bending, according to NP EN 310, in the direction that the laths are glued. It was found that bamboo veneers acted as mechanical reinforcement for the cases of normal traction in the eucalyptus wood, but there was no increase in eucalyptus wood subjected to shear efforts, regardless of the position of growth rings in wood samples. In this case the veneers functioned only as a coating. There was a fragile behavior of the panel EGP of eucalyptus during their break to shear efforts. The tests were repeated for the panels EGP coated with bamboo venners on double-sided. There was then a large increase in mechanical resistance to bending of laminated panel. With the increase obtained was a change in behavior of the panel that failed through the fragile break so ductile rupture, making the panel more elastic and reliable to use. Furthermore were studied the characteristics of roughness of the surface of bamboo veneer when the material is subjected to manual sanding processes / Doutor
4

Understanding the External Firm Factors Impacting Innovation in the Hardwood Veneer Industry

Jahnke, Amy Dyan 15 June 2012 (has links)
Innovation research in the wood products industry has historically focused on factors that the firm can influence or control, as opposed to factors external to the firm. The purpose of this research is to understand how the external factors of the firm (i.e., social, technological, economic, ecological, and political or STEEP factors) impact Schumpeter's five-factors of innovation (i.e., sources of supply, methods of production, markets, products and services, and business models) in decorative hardwood veneer producing firms. Case studies of hardwood veneer firms in Austria and the United States were conducted to understand these impacts from individual firms' perspectives. Innovation strategies of the companies were identified based on their use of innovation resources, leverage of those resources and capabilities to serve customers and markets, and deliberateness or emergence. Interviews of experts in each of the environmental areas from both geographic regions also were conducted to qualify and validate the impacts. An online survey was conducted with hardwood veneer companies in Austria, Germany and the United States to quantify the impacts in these regions, and results were analyzed via cluster analysis to better understand the environmental impacts to innovation and the strategies firms were employing to innovate. The results of the study identified American firms as being most impacted by economic environmental factors and Austrian firms most impacted by social factors. Austrian/German and US firms both made more deliberate than emergent attempts to innovate. US firms most attempted to innovate their business models, while Austrian and German firms most attempted source of supply and product and service innovations. The major implications of this research are the awareness firms in the hardwood veneer industry can gain from understanding the innovation strategies their firms employ, how the environment they function within impacts their innovation, and what they can do about it. By helping this niche industry create sustainable competitive advantages, the industry can overcome the adversities of the mature industry lifecycle phase, including competitive threats from substitute products and increased competition from foreign log buyers, and shift back into a growth phase of the lifecycle. / Ph. D.
5

A comparison between conventional brick and timber-frame brick veneer housing

Mostert, J J J 17 April 2020 (has links)
Timber-frame brick veneer construction originated in countries in which houses were traditionally constructed with loadbearing timber frames which were clad with non-loadbearing weather boarding or similar light-weight materials. Timber-frame house construction is extensively used in countries such as Canada, Scandinavia, Australia and North America. With the Canadian system, buildings of up to three storeys can be erected with loadbearing timber frames. This particular system was also adopted in France - the Igny project~ and in England - the Harlow project. In most of these cases, basements or crawl-spaces underneath the house were incorporated in the design. In these countries there have a trend towards the use of a brick cladding (veneer) for timber-frame structures. This is a comparatively recent introduction in these countries, but it has already been extensively used. This trend is primarily related to the appearance and other advantages (for example durability and ease of maintenance in the case of a face-brick clauding) of a masonry exterior, while largely retaining the low cost benefits of timber-frame construction.
6

Seismic behavior and design of low-rise reinforced concrete masonry with clay masonry veneer

Jo, Seongwoo 03 September 2010 (has links)
The research described here is part of a multi-university project on “Performance-based Design of New Masonry Structures.” Within the context of that project, the main objectives of this research was to study the inelastic seismic performance of low-rise concrete masonry structures with clay masonry veneer and veneer connectors; to develop analytical models for those structures and the elements comprising them; and to use the results of the research to propose refinements to current design provisions for concrete masonry with clay masonry veneer. The experimental work described here includes the design and testing of concrete masonry wall specimens with clay masonry veneer under quasi-static loading. Identical specimens were subjected to shake-table testing at another university. The experimental work described here also includes the design of a full-scale, one-story concrete masonry building specimen with clay masonry veneer. That building specimen was subjected to shake-table testing at another university. The analytical work of this research includes the development of nonlinear hysteretic models for concrete masonry walls, clay masonry veneer and veneer connectors. The analytical models for wall specimens were calibrated using the results of the quasi-static and shake-table tests of wall specimens. The analytical model for the building specimen was compared with and refined using shake-table test results for the building specimen. Finally, the calibrated and refined analytical model of the building specimen was used for parameter studies intended to supply general information about the behavior of low-rise reinforced concrete masonry structures with clay masonry veneer. Based on the these experimental and analytical results, basic concepts of the seismic response and design of low-rise concrete masonry buildings were reaffirmed; most design and construction requirements of the 2008 MSJC Code and Specification were reaffirmed; and several recommendations were made to improve those requirements. / text
7

Feasibility of Multi Storey Post-Tensioned Timber Buildings: Detailing, Cost and Construction

Smith, Tobias James January 2008 (has links)
This thesis describes a feasibility study into the use of a new method of timber construction developed in New Zealand. This new method combines the use of an engineered wood product (Laminated Veneer Lumber) and post-tensioned ductile connections. Three case study buildings are presented in concrete, steel and timber all representing current design and construction practice. A fourth building, referred to as the “timber plus” structure, is also considered with the addition of timber architectural components. The case study timber building consists of two lateral resisting systems. In one direction post-tensioned LVL moment resisting frames are used, with post-tensioned cantilever walls in the orthogonal direction. Timber-concrete composite floor units are also used. The method of design and detailing of the timber building is shown with member sizes being found to be comparable to that of the concrete structure. Sub-assembly testing is performed on some key connections with excellent results. Construction time is evaluated and compared to the concrete structure with similar construction times being achieved. Finally the costs of the case study buildings are calculated and compared. The costing found the four options to be similar in price with the Timber and Timber plus buildings showing only a 6% and 11% increase in total cost respectively.
8

The Fire Performance of Timber-Concrete Composite Floors

O'Neill, James William January 2009 (has links)
Timber-concrete composite floors are a combination of timber joists and concrete topping, creating a flooring system to best utilise the advantages each material has to offer. Timber is used as the main tensile load bearing material due to its high strength-to-weight ratio, while concrete is used in floor slabs for its advantages in stiffness and acoustic separation. The strength of the system is dependent on the connection between timber and concrete, thus the connection must be strong, stiff, and economical to manufacture, to ensure that the flooring system is economically viable. This research investigated the fire performance and failure behaviour of timber-concrete composite floor systems currently under development in New Zealand, resulting in a calculation method for evaluating the fire resistance of these floors. Furnace tests were performed on two full-size floor specimens at the Building Research Association of New Zealand (BRANZ). Both floor specimens were 4 m long and 3 m wide, consisting of 65 mm concrete topping on plywood formwork, connected to double LVL floor joists. They were tested over a 4 m span, subjected to a nominal design live load of 2.5 kPa. Both floors were subjected to the ISO 834 test fire for over 60 minutes. Two separate connection types were tested; concrete notches cut into the timber beams with an incorporated shear key, and metal toothed plates pressed between the double beams. It was found that the reduction in section size of the timber beams due to the fire governed the failure mode of the floors. Due to the composite action achieved by the connections, the floor units were able to withstand prolonged exposure to the test fire, well exceeding one hour. The test data and visual observations aided in the development of a numerical model for evaluating the fire resistance of the floors. This was developed in a spreadsheet that is able to predict the expected fire resistance of these floors, taking into account some major time dependent variable properties that can have an effect on the overall performance. Load-span tables have been produced to give the estimated fire resistance of floors with differing floor dimensions, span lengths and applied loads.
9

The Environmental Performance of Brick Veneer / Steel Stud Curtain Wall Systems Subject to Air Pressure, Temperature and Vapour Pressure Differentials

Kluge, Andrew 05 1900 (has links)
Brick veneer / steel stud curtain wall systems have become a popular alternative in the ever competitive construction market. However, the application of such systems has preceded any formal scientific investigation into its long term serviceability and safety. Of particular interest to many parties is the performance of the wall system under typical winter conditions as would be encountered in cold climate countries such as Canada. In this study, an experimental investigation of three types of brick veneer / steel stud curtain walls was performed with a specially built apparatus used to impose air pressure, temperature and vapour pressure differentials across test specimens. In all, five wall specimens were tested for air leakage, thermal performance and moisture accumulation. An analytical investigation was also carried out with a simple, custom made finite difference computer program specially suited to determine temperature profiles in walls with a steel stud framing system. Six types of walls are evaluated with the model. A significant part of the research involved the design, construction and improvement of the test apparatus. Since the apparatus is unique, a chapter is devoted to its description. The conclusions presented indicate that certain wall designs perform poorly and that even small construction flaws can lead to serviceability problems. Conversely, care in choice and placement of the air barrier, vapour barrier and thermal insulation in the wall system can lead to a wall system that can sustain a small degree of construction errors and at the same time perform satisfactorily. It is furthermore concluded that the apparatus built for this study has real potential as a cost effective test tool suitable for adaptation for a standard test method to evaluate the environmental performance of wall systems in general. / Thesis / Master of Engineering (ME)
10

Holzwerkstoffe in technischen Anwendungen – Anforderungen aus Sicht des Maschinenbaus / Wood as a Material in Mechanical Engineering - Concerns and Requirements

Müller, Christoph, Eichhorn, Sven, Krug, Detlef, Weber, Andreas 12 September 2012 (has links) (PDF)
Im Vortrag werden die Holzwerkstoffe charakterisiert und anderen Konstruktionswerkstoffen und technischen Verbundmaterialien gegenüber gestellt. Anhand eines Ausführungsbeispiels wird deren technologische und wirtschaftliche Leistungsfähigkeit analysiert. Darauf aufbauend werden notwendige Maßnahmen zur Verbesserung der Werkstoffe sowie zu deren Etablierung in der Technik dargestellt. Aus dem Vergleich der jeweiligen Eigenschaftsprofile werden zukünftige Nutzungsmöglichkeiten der Holzwerkstoffe in der Technik abgeleitet. Ein Ausblick zeigt den möglichen Entwicklungsspielraum für Holzwerkstoffe in technischen Anwendungen. / The properties of wood materials are compared to several engineering materials, like metal alloys, polymers and fiber reinforced plastics. The technologic and economic efficiency of plywood is illustrated by the implementation of a wooden beam. Accordingly necessary measures for the improvement of wood materials and their recognition in mechanical engineering are shown. A perspective of further fields of applications for wood materials in a technical context is given.

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