Plywood is composed of several thin layers of wood bonded together by glue. The adhesive integrity of the glue formulation employed must surpass the structural integrity of the wood species within a given panel of plywood. The American Plywood Association (APA) regularly tests the plywood produced at various plywood manufacturing plants to ensure that this particular performance requirement is consistently met. One of the procedures used by the APA to test this requirement consists of 1) milling a plywood panel to be tested into small rectangular blocks called samples, 2) conditioning these samples with various treatments to simulate natural aging, 3) shearing each sample into two halves, and 4) estimating the percent wood failure (as opposed to glue failure) produced by the shear by visually inspecting these sample halves. A region of solid wood or a region of wood fibers embedded in glue on the shear of a sample half is a region of wood failure while a region of glue is a region of glue failure. If the wood failure of samples from a significant number of panels is too low, the right to use APA trademarks is withdrawn from the plant where the sampling occurred. Since measurements obtained by human visual inspection can contain inaccuracies due to fatigue, boredom, state of mind, etc., an automatic vision system to determine percent wood failure is proposed. The method presented is a refinement of the method developed by McMillin and is divided into three tasks. The first task is to locate the area of shear on a given sample half. The second task is to distinguish the areas of wood from the areas of glue on the shear of a sample half. Solid wood is distinguished from glue based on the difference in gray level intensity that exists between solid wood and glue. Wood fiber is distinguished from glue based on the difference in texture, i.e., edge patterns, that exists between fiber and glue. The third task is to compare the areas of shear on the two sample halves comprising a sample to determine the percent wood failure of the sample. / Master of Science

Timber has experienced new interest as a building material in recent times. Although traditionally in New Zealand it has been the main choice for residential construction, with recently introduced engineered wood products like Laminated Veneer Lumber (LVL), the use of timber has developed to other sectors like commercial, industrial, and multi-story buildings. The application of timber in office and commercial buildings poses some challenges with requirements for long span timber beams yet with holes to pass services. The current construction practice with timber is not properly suited for the aforementioned types of structures. There has been significant progress in designing timber structures since the introduction of timber codes like NZ3603-Timber Structures Standard; however, there are still a number of problems such as holes in beams not being addressed in the code. Experimental and numerical investigation is required to address the problem properly. In Europe, there have been a few attempts to address the problem of cutting holes and strength reduction because of holes/penetrations in glulam beams. However, LVL has not received much attention due to smaller production and use. While other researchers are focusing on glulam beams with holes, this research is targeting LVL beams with holes. This thesis extends existing knowledge on LVL beams with holes and reinforcement around the holes through experimental tests and numerical analysis. An experimental program on LVL specimens has been performed to indicate the material properties of interest that will be used in the analysis and design chapters through whole of the thesis. A wide-ranging experimental program was also performed on beams with holes, and beams with reinforcement around the holes. The experimental program pushes forward existing methods of testing by measuring the load in the reinforcement

Mémoire (M.P.M.O.)-- Université du Québec à Chicoutimi, 1990. / Ce mémoire a été réalisé à l'Université du Québec en Abitibi-Témiscamingue dans le cadre du programme de maîtrise en Gestion des PMO extensionné de l'UQAC à l'UQAT. CaQCU Document électronique également accessible en format PDF. CaQCU

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The study was designed to evaluate the relative importance of certain factors influencing the strength properties of cold-pressed Douglas fir plywoods normal to glueline. In addition, estimates of strength values were also sought. Rotary-cut veneers were obtained from plywood mills; sawn veneers were prepared from lumber. A 2 x 3 x 3 factorial design was followed using veneer thicknesses of 1/10, 1/7, and 1/5 inch, and gluing pressures of 50, 200, and 350 psi. A cold-setting modified polyvinyl adhesive (Duro-Lok 50) was used in all 18 plywood blocks fabricated. From each of these, 8 tension, 4 compression and 3 glue shear specimens were prepared. Their dimensions were ½ x 1 x 4 1/2 inches, 1 x 1 x 4 1/2 inches and 1 x 3 1/4 x 3/5 inch, respectively. Plywoods of sawn veneers were only half as strong as solid wood in both compression and tension. Solid wood exceeded the compressive strength of rotary-cut veneer blocks by two, and tensile values by seven times. Stiffness of sawn veneers was twice that of rotary cut ones. The ratio of moduli of elasticity in compression to those in tension was found to approximate seven and six for the two veneer types, respectively. The difference between solid wood and sawn-veneer block strength might be attributed mainly to the influence of a suspected acid hydrolysis at the gluelines or possibly to specimen geometry. The much lower strength values of rotary-cut veneers must have resulted from the presence of lathe checks, and the lower quality of veneer surfaces. The functional dependence of all strength properties upon some independent factors, and the ranking of the latter, was established and evaluated by multiple regression analyses. The combination of the 16, 17 or 18 most important veneer and plywood variables accounted for practically all the variation, especially for rotary-cut veneers. In addition, the complete dependence of some plywood variables on independent veneer characteristics and gluing techniques were shown by regression equations. It should be noted that the three experimentally controlled factors, veneer type, veneer thickness and gluing pressure, were not always all included in the six most significant ones. The rank of variables was found to differ for each of the various strength properties observed. Analyses of variance were performed for both observed and adjusted values within each veneer type, both providing almost identical results. The high significance of veneer thickness has been shown for all strength properties, barring shear. This was explained by its strong correlation with a number of independent variables, such as glue content and specific gravity. Gluing pressure exerted a highly significant influence on all strength properties of rotary-cut veneer blocks, and in compressive stress and strain of sawn-veneer plywood construction. Its influence was attributed to the strong correlations indicated between it and other variables, for example, full compression and plastic deformation. Finally, the exploratory nature of the experiment was emphasized. / Forestry, Faculty of / Graduate

The influence of lathe checks on shear strength of Douglas fir plywood was investigated by means of impregnating lathe checks of rotary-cut veneer to various depths using a phenol-formaldehyde resin. Comparative tensile shear strength tests were conducted on a Table Model Instron machine and photographs taken at various stages of load application to illustrate the varied manner of failure. Strength of rotary-cut veneer plywood was about 60 to 70% that of sawn veneer plywood, but after the lathe checks of core veneer were impregnated by resin there was no significant difference between them. The shear strength (Y) was found to be highly correlated with penetration depth of adhesive into lathe checks (X). The linear relationship between these factors was: Y = 228.22 + 1.28052X (SE[subscript]E = 21.82; r = 0.893). Per cent wood failure estimated by conventional methods failed to relate to shear strength. Rather, the per cent wood failure occurring within 10$ of the initiation of an annual increment was found to be a better indicator of shear strength. Use of photography helped to explain more clearly stress distribution and wood failure in the specimens. It was found that the ultimate strength was reached in conventional plywood when the lathe checks were just opening. Core-impregnated plywood was used in a test to compare the tensile shear resistance when tight-side and loose-side of veneer was next to the glue line. Neither strength nor wood failure were significantly different between the two. Tensile shear strength for plywood made of impregnated core veneer and untreated face veneer was two to three times as high as that of conventional plywood. The per cent wood failure in core veneer and shear strength varied inversely. Results obtained in this study indicated that it is feasible to develop a plywood which has shear strength as high as 500 psi while remaining economical to manufacture. / Forestry, Faculty of / Graduate

Orientador: Ivaldo De Domenico Valarelli / Banca: Marcus Antonio Pereira Bueno / Banca: Gilberto de Magalhães Bento Gonçalves / Banca: Eduardo Carlos Bianchi / Banca: Alexandre Jorge Duarte de Souza / Resumo: A pesquisa se deu através na produção de painéis de MDF (Medium Density Fiberboard) em escala laboratorial utilizando o adesivo a base de Uréia Formaldeído (UF), aditivado com o adesivo a base de látex natural de seringueira na condição centrifugada, onde foram avaliadas, além das características físicas e mecânicas dos painéis produzidos, também teve como objetivo verificar a emissão de formaldeído para o ambiente, quando aplicado o aditivo látex, e analisar os perfis de densidades ao longo da espessura dos painéis. As amostras foram confeccionadas com fibra de eucalipto, onde a dosagem do adesivo UF foi de 11%, e para efeito de comparação com as amostras produzidas com o aditivo látex, foram fabricadas provas em branco (PB) com somente o adesivo UF, e as demais foram aditivadas com látex seguindo as proporções de 10, 15 e 20%, sobre o teor de sólidos da resina UF, sendo denominados os traços formulados como T1 (PB - 0% látex), T2 (10% látex), T3 (15% látex), e T4 (20% látex), respectivamente. No total foram produzidas 8 amostras, dois painéis de cada traço, e retirados os corpos de prova, que posteriormente foram avaliados conforme a NBR 15316-2 (2015) para as condições secas. Os principais insumos foram fornecidos pelo fabricante de painéis Duratex SA, e os testes foram realizados nos laboratórios da empresa. O aditivo látex mostrou-se bastante promissor, apresentando grande compatibilidade com os demais componentes da formulação, e favorável para fabricação de MDF. Divers... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The research was done through the production of MDF (Medium Density Fiberboard) panels in laboratory scale using the Formaldehyde Urea based adhesive, added with the natural rubber latex based adhesive in the centrifuged condition, where they were evaluated, Besides the physical and mechanical characteristics of the panels produced, the objective was also to verify the formaldehyde emission to the environment, when the latex additive was applied, and to analyze the density profiles along the thickness of the panels. The samples were made with eucalyptus fiber, where the dosage of the UF adhesive was 11%, and for comparison with the samples produced with the latex additive, blank tests (PB) were made with only the UF adhesive, and the others were added with latex following the proportions of 10, 15 and 20%, on the solids content of the resin UF, being denominated the traces formulated as T1 (PB - 0% latex), T2 (10% latex), T3 (15 % latex), and T4 (20% latex), respectively. In total 8 samples were produced, two panels of each trait, and the specimens removed, which were later evaluated according to NBR 15316-2 (2015) for dry conditions. The main inputs were supplied by panel manufacturer Duratex SA, and the tests were performed at the company's laboratories. The latex additive was very promising, showing great compatibility with the other components of the formulation, and favorable for the manufacture of MDF. Several features were able to meet the requirements of the standard,... (Complete abstract click electronic access below) / Doutor

Stress and performance related sick leaves is a growing problem in architecture schools. This work aims to find a way to work with a project that includes physical and mental well-being. By tracking everything we do, consume, feel and other external circumstances we have built up a large base of information about ourselves. Data that we have analyzed and tried to understand when and why we are doing well, and if it has any relation to how we work. To have something to measure against, we have created a architectural project, in form of a full scale volume. The design process fore this volume is made from ourselves and our bodies, in extension the data. The two tracks has been very codependent, and could not function without each other. The project has worked as a guid, a help for us in our further life as architects. We are two people with different way of thinking. We have different results on what’s working. We want to convey that this project is very personal and not a general manual for architects. It is a study in how one can think to finding a working-method that is good for one's self.

"This paper investigates the thermal conditions at the surface and at depth of 1.8 cm (3/4-inch) maple plywood exposed to heat fluxes between 6 and 15 kW/m2 in the cone calorimeter for up to 8 hours. The minimum heat flux for unpiloted smoldering ignition was 7.5 kW/m2 and compared favorably to classical self-heating theory. The role of self-heating was explored via temperature measurements distributed within the specimens. Elevated subsurface temperature profiles indicated self-heating was an important ignition factor resulting in ignition at depth with smolder propagation to the surface and into the material. The ignition depth was shown to be a function of the heat flux with the depth moving towards the surface as the heat flux increased. Supporting work included sensor calibration testing, mass loss rate analysis, char depth testing and computer modeling. The calibration testing showed optical pyrometer temperature measurements compare favorably to those of surface mounted thermocouples. Mass loss rate analysis was found to be a lagging indicator of smoldering ignition. The char depth tests showed that the rate of change of the temperatures recorded at depth increased around the time the derived char front passed. Computer modeling (HEATING) of a heat flux applied to the plywood for conditions similar to the performed ignition tests compared favorably to experimental data for sub-critical incident heat flux temperature profiles, excepting surface temperatures. For heat fluxes near critical, the model correctly predicted thermal runaway below the sample surface. At higher heat fluxes simulation results indicated surface ignition at times significantly earlier than experimental results."

O presente estudo teve como objetivo principal avaliar o potencial da madeira de dois clones do híbrido Eucalyptus grandis x Eucalyptus urophylla para a produção de lâminas e manufatura de painéis compensados. Foram coletadas 5 árvores para cada clone (I e II) e duas toras de cada árvore, sendo uma da base (A) e outra subseqüente (B), totalizando 20 toras. As toras após descascamento e aquecimento em água quente foram processadas em torno laminador gerando lâminas de 2,00 mm de espessura nominal. O rendimento médio do processo de laminação foi de 51,74% para as toras do clone I e de 56,81% para as toras do clone II. A qualidade das lâminas produzidas foi avaliada com base na Norma de Controle de Qualidade e Classificação de Compensados, da ABNT. O clone I gerou lâminas de melhor qualidade: 11,94 % na classe A; 32,84 % na B; 54,48 % na C e 0,75 % na classe D, enquanto que o clone II gerou: 1,20 % na classe A; 8,40 % na B; 67,47 % na C e 22,89 % na classe D. Foram manufaturados compensados de 5 camadas, com lâminas da classe C para as capas e o miolo, coladas com adesivo à base de uréia-formaldeído. Os fatores de tratamento empregados na manufatura foram: clone (I e II), gramatura de cola (320 e 360 g/m2) e tempo de prensagem (8 e 12 minutos). O delineamento experimental foi inteiramente casualizado com arranjo fatorial do tipo 2 x 2 x 2. A partir dos compensados manufaturados foram obtidos corpos de prova para avaliação das propriedades físicas - massa específica aparente, absorção superficial de água, absorção total de água, inchamento mais recuperação em espessura e recuperação em espessura, e avaliação das propriedades mecânicas - flexão estática paralela e perpendicular (MOR e MOE) e resistência da linha de colagem ao esforço do cisalhamento nas condições seca e úmida. A análise estatística dos resultados das propriedades físicas e mecânicas foi realizada através de uma análise de variância. Não houve interação significativa entre os fatores clone, gramatura de cola e tempo de prensagem, considerando todas as variáveis avaliadas. Foram detectadas diferenças significativas para o fator clone em relação às variáveis massa específica aparente (maior para o clone I), absorção superficial e total de água (menores para o clone I); resistência da linha de colagem ao esforço do cisalhamento - condição seca e flexão estática - MOR paralelo e perpendicular (maiores para o clone I). Para o fator gramatura de cola não houve diferença significativa entre os tratamentos para nenhuma das variáveis avaliadas. Houve diferença significativa para o fator tempo de prensagem em relação às variáveis absorção superficial de água (menor para o tempo de prensagem de 12 minutos), inchamento mais recuperação em espessura e recuperação em espessura (menores para o tempo de prensagem de 8 minutos). A conclusão do trabalho é que as madeiras de ambos clones do híbrido Eucalyptus grandis x Eucalyptus urophylla apresentam alto potencial para produção de lâminas e manufatura de compensados. / The main objective of this work was to evaluate the potencial of eucalyptus grandis x Eucalyptus urophylla hybrid clones wood for plywood and veneer production. Five (5) trees were collected for each clone (I and II) and 2 logs of each tree, being one from base (A) and other subsequent one (B), totaling 20 logs. The logs after debarked and heated in hot water were processed in rotary cutting lathe generating veneers of 2,00 mm nominal thickness. The peeling yield was evaluated and mean values were 51,74% from clone I logs and 56,81% from the II one. The veneer quality graded was conduced following Norma de Controle de Qualidade e Classificação de Compensados, Brazilians standards. The clone I generated veneers of better quality: 11,94% of grade A veneer; 32,84% of B; 54,48% of C and 0,75% of grade D veneer, while the clone II generated: 1,20% of grade A veneer; 8,40% of B; 67,47% of C and 22,89% of grade D veneer. 5 layers plywood was manufactured with grade C veneers. The plywood manufacture treatment factors were: clone (I and II), glue amount (320 and 360 g/m2) and press time (8 and 12 minutes). From manufacture plywood were obtained specimens to evaluate the physical properties - apparent specific mass, superficial absorption of water, total absorption of water, thickness swelling more thickness recovery and thickness recovery, and the mechanical properties - parallel and perpendicular static bending (MOR and MOE) and bonding line shear test in the dry and wet conditions. The result obtained during the physical and mechanical assessments of plywood were analyzed using a variance analysis, executed by SAS (Statistical Analysis System). There was not significant interaction among the factors clone, glue amount and press time, considering all the appraised variables. Significant differences were detected for factor clone in relation to the variables apparent specific mass (clone I higher than clone II), superficial and total absorption of water (clone I smaller than clone II); bonding line shear test (dry condition) and static bending - parallel and perpendicular MOR (clone I higher than clone II). To the factor glue amount there was not significant difference among the treatments for none of the appraised variables. There was significant difference for the factor press time in relation to the variables superficial absorption of water (12 minutes smaller than 8 minutes), thickness swelling more thickness recovery and thickness recovery (8 minutes smaller than 12 minutes). It's concluded that Eucalyptus grandis x Eucalyptus urophylla hybrid clones wood have a high potencial for phywood and veneer production.