Thesis (M.S.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 64-66). Also available on the World Wide Web.

The gluing properties of pyinkado (Xylia dolabriformis Benth.), thitya (Shorea obtusa Wall.), ingyin (Pentacme siamensis Kurz.), padauk (Pterocarpus macrocarpus Kurz.), in (Dipterocarpus tuberculatus Roxb.), and kanyin (Dipterocarpus sp.) from Burma were investigated. Three room temperature curing glues, phenol-resorcinol-formaldehyde (exterior), urea-formaldehyde (interior), and casein were used. Specific gravity, shrinkage, pH and extractive content were determined for each wood species and their influence on the gluing properties discussed. Block shear specimens for phenol-resorcinol-formaldehyde were tested dry, cold soak, boil and vacuum-pressure treated. Percent delamination was measured. Wood glued with urea-formaldehyde was tested dry and after cold soaking, whereas that glued with casein was only tested dry. In and kanyin (specific gravity 0.67 and 0.59, respectively) showed wood failure values above 90 percent and good shear strength with all the three glues. Pyinkado (specific gravity 0.75) showed high shear strength with all the three glues. It developed 81 percent wood failure with phenol-resorcinol-formaldehyde, 86 percent with urea-formaldehyde but only 22 percent wood failure with casein. Padauk (specific gravity 0.77) developed high shear strength with casein (2,709 psi), but slightly lower shear strength values with phenol-resorcinol formaldehyde (2,693 psi) and urea-formaldehyde (2,448 psi). It had 78 percent wood failure with phenol-resorcinol-formaldehyde and 87 percent with urea-formaldehyde but only 67 percent wood failure with casein. Ingyin and thitya (specific gravity 0.81 and 0.80, respectively) showed low shear strength and low wood failure percent with all the three glues. In and kanyin showed low percentage of extractives soluble in ether (1.8 and 1.3 percent, respectively), ethanol (0.5 and 1.4 percent, respectively), hot water (0.5 and 0.4 percent, respectively), and acetone (2.5 and 2.2 percent, respectively). No direct relationship was observed between percentage extractives in the solvents used and shear strength or gluability. If the influence of specific gravity is excluded, a trend of increase in glue joint strength with increase in wood pH was observed. The pH of the wood was from 4.47 to 5.09. The vacuum-pressure treatment reduced the dry shear strength of all species more so for in (37 percent) and kanyin (34 percent). All species, except ingyin and thitya, still showed high wood failure. High delamination percent was observed for pyinkado (22 percent), thitya (68 percent), and ingyin (34 percent), and low delamination for in (8 percent), kanyin (8 percent), and padauk (11 percent) with phenol-resorcinol-formaldehyde. The boil test was observed to reduce glue joint strength most for all species. The reduction was 57 percent for ingyin, 53 percent for in, 50 percent for kanyin, 30 percent for pyinkado and thitya, and 19 percent for padauk. Wood failure percent was high for all species except thitya and ingyin. Padauk, in and kanyin meet the requirements for exterior structural lamination with phenol-resorcinol-formaldehyde. Ingyin, thitya and pyinkado failed to meet the requirements. Padauk, pyinkado, ingyin, in and kanyin meet the minimum requirements for interior structural lamination with urea-formaldehyde. Kanyin, in and padauk are considered suitable for interior structural lamination with casein. Further study is recommended for ingyin, thitya, and pyinkado for gluing with phenol-resorcinol-formaldehyde for exterior structural lamination; pyinkado, ingyin and thitya for gluing with casein; and thitya for gluing with urea-formaldehyde for interior structural lamination. / Forestry, Faculty of / Graduate

No description available.

The underlying cause was sought for "inactivation", a heat-induced change in the surface of veneer that inhibits diffusion of moisture into the wood. It was demonstrated, by the use of Douglas fir wood, that the formation of an inactivated surface could be prevented by extraction with certain organic solvents, but not with water, either before or after the wood was dried. When the extractable materials were removed, or were originally absent, no specimen examined showed degradation, through the effect of heat, of the potential for forming strong glue bonds. The frequently postulated statement related to formation of ether linkages from hydroxyl groups, in heated wood, was found to be not correct. Although oxidation had been suggested as a contributing factor, inactivated surfaces were prepared in the absence of oxygen in anything but minute amounts. Veneer was collected from Coastal and Interior type Douglas fir trees that exhibited severe, moderate or no susceptibility to the development of inactivation. Representative samples were extracted with simple alkanes and a complete separation of the various components carried out, using the techniques of gas/liquid, paper and thin-layer chromatography. Qualitative variability was found, between and within trees. Strong correlation was found between the formation of an inactivated surface and the presence of saturated fatty acids with carbon-chain lengths in excess of eighteen atoms. The role of long-carbon-chain, saturated fatty acids as the causal agent of inactivation was substantiated by the application of commercially-prepared acids, of various chain lengths, to veneer that had proven insusceptible. When heated, this veneer developed an inactivated surface. A theory was proposed, based on the work described in this thesis, and the information available in the literature, to explain the mechanism of surface modification. It states that removal of some or all of the last molecular layer of water from the wood surface, and the application of heat, permits the saturated long-chain fatty acids to hydrogen-bond with the hydroxyl groups contained in the wood cellulose. The surface of the wood is then shielded by a hydrocarbon layer with very low free surface energy that is not- readily wet-table by the water contained in applied glue. / Forestry, Faculty of / Graduate

The aim of this study has been to investigate the possibilities to identify lack of glue in finger joints by checking different non-destructive techniques. Specifically, this study puts emphasis on finding a method suitable for an automated and fast industry production line of home furnishing products. The methods investigated are of three main varieties: Sound/vibration Thermography Tomography The most promising method was the high-power ultrasound thermography. This method is fast and reliable, but more research is needed. It is necessary to find out if the thermography waves can penetrate deep enough. Another possible method is computed tomography. This method can take a lot of time, but the speed of scanning depends on the accuracy demanded. / Uppgiften har varit att granska möjligheterna att identifiera bristfälliga trälimningar eller helt avsaknad av lim i fingerskarvar med hjälp av olika metoder som inte förstör materialet, NDT (non-destructive testing). Undersökningen syftar speciellt till att finna en metod som är anpassad till ett effektivt produktionsflöde i industrin. Det måste där med vara en metod som med stor snabbhet kan hitta eventuella fel på produkterna. De metoder som mer omfattande har granskats är ljud/vibration, termografi och tomografi. Den metod som visat sig mest lovande är high-power ultrasound thermography. Tester måste dock utföras för att säkerställa att metoden är passande för ändamålet. Framför allt om de termografiska vågorna tränger in tillräckligt djupt. En annan möjlighet är datortomografi. Denna metod kan vara tidskrävande, men skanningshastigheten beror på hur noggrant mätresultat som erfordras. Här finns också en säkerhetsaspekt som måste beaktas, eftersom röntgenstrålar används.

The advantage for new carbon fiber bipolar plate are as follow, low cost, light weight, low contact resistance and good chemical stability. After process automation, to further reduce costs, enhance quality stability, improve production efficiency, bipolar plates can be achieved mass production. Bipolar plate manufacturing process is divided into five parts:(1) the unfolding of carbon fiber (2) automation of gluing (3) hot-compression harden (4) cutting of carbon fiber bunch (5) Injection molding of bipolar plates. Without leakage, tightness test of the carbon fibers must reach a pressure of 0.2 kg/cm2. The contact resistance is lowest when number of carbon fiber has 160 layers, and compressed fiber bunch height of 2mm on the assembly. Anode inlet pressure is 0.1 kg/cm2. Cathode is required to install a fan. And the fan speed has to cooperate with current load. The quality of carbon fiber bunch will affect the performance of the battery, such as the wide of the rubbers, the flat of the section, Tightness, and numbers of fibers. The structure of the bipolar plate must be considered fuel transfer and number of carbon fibers bunch. Fuel supply and the contact resistance value to achieve a good balance.

The purpose of this thesis is to investigate the possibilities of automating a gluing process in the optical manufacturing industry. Aimpoint, a Swedish company that manufactures red-dot sights was the industrial partner in this thesis. Since the optical quality of their products is of the highest importance and the lenses and protective glass are for the most part glued using traditional, manual methods, the company aims to find improvements and methods to ensure the qualityof their products by automating this process. A number of requests were submitted, including the ability of such an improved process to be able to glue lenses of more complex geometries than the mostly round lenses currently used. To allow precise adhesive dispensing around the lens of a sight with a complex geometry, Aimpoint has two Cartesian tabletop dispensing robots. This kind of robot servesas a baseline for the comparisons in this thesis. A Franka Emika articulating robot arm was used to test the possibilities of au-tomating the process using such a robot system. Firstly, a motion was generatedbased on the CAD model of the product. The motion generation and manipulation was performed in MATLAB where the Peter Corke robotics toolbox was used for initial simulations. Unfortunately, the robot model in the toolbox was not able to take joint limitations into account and a migration to ROS was in order. Since there was no implementation for Cartesian control in the simulation software for Franka Emika, a decision was made to start physical tests using the robot pre-maturely. As for the adhesive dispensing, tests were conducted to investigate the parameters that affect the termination of a glue joint such as the retract setup and timings. A repeatability test was also conducted to test the performance of dis-pensing using a direct pressure fed adhesives syringe versus using a dispensingvalve. With the knowledge and data from these tests, the experimental setup was built at the robot lab in Lund where a computer ran the controller implementation, controlling the robot and an Arduino was utilized to actuate the dispenser. Several details were glued on this setup, both with vertical and angled nozzle. Asa reference for gluing, a detail was glued using the Cartesian dispensing robotat Aimpoint with the same limited path as previously described. To analyse the performance of the glued joint, a push-out test was conducted at Aimpoint usinga tensile strength machine. The results from this test showed that a glue joint glued with an angled nozzle was stronger and a higher force was required to deform the joint compared to one glued with a vertical nozzle. On average, the joint glued with an angled nozzle required 721 N and the vertical required 395 N. It is concluded that keeping the nozzle angled during the dispensing operation yield a stronger glue joint and makes the system less sensitive to positionand orientation errors. As for the impedance controller used in this thesis, it is concluded to not be suitable for the considered application and its requirements. Regarding the robotic solution investigated in this thesis, it was observed to bebeneficial to utilize a high number of axes when generating the motion for the gluing operation. However, case-consistent inverse kinematics is a requirementto further investigate this claim.

Flat roofs are very desired type of building roofing these days. We can find flat roofs in construction of family and apartment houses, manufacturing and storage buildings, office buildings, shopping centres, etc. and not only in constructions of new building, but in substantial amount also during reconstruction. For every flat roof it is necessary to design a way of roof plies stabilization against wind suction. Gluing is one of many used methods of flat roof stabilization. The gluing itself can be implemented by innumerable adhesives of various compositions from many manufacturers. Gluing has advantages and disadvantages as every method. Lack of information can be considered as key disadvantage. Especially the lack of information about strength of gluing joints. The dissertation is focused on polyurethane adhesives, their application for stabilization of layers in flat roof and experimental determination of strength values of glued joints. The first phase of the dissertation aims to create a test methodology for experimental measurements. As a part of the methology to create a test model, a test apparatus and a procedure for experimental measurements. In next phase dissertation focuses on experimental measurements and their evaluation. Research was primarily focused on properties of gluing joint depending on the amount and type of the adhesive, material of bonding layers and technological indiscipline. The results of experimental measurement provide numerical values of strength of the gluing joints and pointed to risky situations which can occur during realization. The conclusion provides practical recommendations and possible opportunities for continuation of the work on this topic.

No description available.

No presente trabalho avaliou-se a resistência mecânica do bambu nos estágios pré e pós processamento mecânico para servir de referências básicas do estudo das propriedades mecânicas de vigas laminadas coladas simples, de seção composta e de seção composta na forma de I, industrializadas em laboratório. Iniciou-se com a caracterização do material bruto na forma de ripa que representa toda a parede do colmo, passando-se pelo material processado na forma de lâmina que representam a parte industrialmente útil da parede do colmo e culminando na manufatura e qualificação das vigas laminadas coladas. Na produção dos corpos de prova do material bruto manteve-se a espessura original da ripa, exceto para alguns produzidos para se avaliar a resistência ao cisalhamento radial das camadas interna e externa da parede do colmo. As ripas foram usinadas em diversas máquinas para serem transformadas em lâminas que são as unidades de composição das seções compostas pela técnica de aglutinação e adesão a frio. Foi estudada também a influência do nó na resistência ao cisalhamento radial e tangencial tanto do material sólido quanto do plano de cola e nas propriedades da flexão. A geometria e as dimensões dos corpos de prova de cisalhamento foram adaptadas da norma ASTM D 905 e os de flexão da norma NBR 7190. As resistências ao cisalhamento no plano de cola e as propriedade da flexão foram determinadas segundo três combinações de faces de contato no processo de colagem com o adesivo à base de resorcinolformaldeído (RF). Estudou-se também a pressão adequada para colagem dos corpos de prova e eleita a mais adequada à colagem de vigas laminadas coladas. Os corpos de prova intactos e rompidos nos ensaios foram observados em microscópio eletrônico de varredura, em microscópio óptico, em microscópio óptico de fluorescência e microscópio estereoscópico. Observou-se ampla variabilidade das propriedades mecânicas tanto do material sólido quanto do material composto, mas em qualquer dos casos de resistência houve ampla variabilidade dos dados e, no geral o material sem nó foi mais resistente do que o com nó. As rupturas ocorreram na maioria das vezes no tecido parenquimático desviando-se dos feixes de fibras e tendendo a seguir a grã do material observando que o plano de ruptura só coincide com o plano planejado para a ruptura quando o corpo de prova é feito com a consideração precisa da orientação da grã. Os corpos de prova montados com a cola à base de PVA e com lâminas nodais responderam de forma satisfatória à colagem a baixa pressão, enquanto que os fabricados com lâminas internodais apresentaram melhor desempenho a alta pressão. Para os corpos de prova manufaturados com o adesivo à base de RF, a melhor combinação de colagem se deu no contato entre faces externas de lâminas. Foi possível observar a penetração do adesivo nos elementos anatômicos das lâminas com o uso da microscopia óptica e de fluorescência. As vigas laminadas coladas de seção transversal composta foram ensaiadas à flexão, mas não romperam por tensão normal, pois apresentaram instabilidade lateral durante o carregamento à flexão. As vigas também apresentaram baixo módulo de elasticidade porque o esmagamento da mesa inferior, nos apoios, foi cofundida e somada pelo sistema de medida, ao valor da flecha. Numa análise geral, a qualidade mecânica da Viga \"I\" pode ser considerada muito boa dentro do correto cálculo do momento de inércia se seções transversais compostas. As camadas perpendiculares ao eixo da via, tanto na alma quanto na mesa, foram tão eficientes na absorção do esforço cortante que não houve nenhuma limitação de capacidade de carga pela ligação alma-mesa mesmo com a viga trabalhando numa faixa de alta influência de tensões cisalhantes. / In this study it was evaluated the bamboo strength in the stages before and after mechanical processing in order to obtain basic references to study the mechanical properties of simple glued laminated beams of composite section and composed section as I joist, manufactured in laboratory scale. It started with the characterization of raw material as strip representing the crude bamboo culm wall, moved to the processed material as in the shape of laminas which were representing the majority of bamboo culm wall industrially useful and culminating to the manufacture and qualification of glued laminated beams. In the production of specimens of raw material it was maintained the original thickness for the strip except for a few ones which were produced to evaluate the radial shear strength in the inner and outer layers of the culm wall. The strips were machined on some machines to be turned into laminas that were the units for assembling composite sections by agglutination and adhesion under pressure in environmental conditions. It was also studied the node influence in the radial and tangential shear strength in both solid material and in the adhesive plan and in properties got from the bending tests. The geometry and dimensions of the shear specimens were adapted from ASTM D 905 and the bending from NBR 7190. Shear strength in the adhesive plane and bending property were determined following three combinations of contact faces on the gluing process using resorcinol-formaldehyde based adhesive. It was studied also the proper pressure for gluing the specimens and elect the most suitable for glued laminated beams. The intact specimens and failed on mechanical tests were observed under a Scanning Electron Microscope, Optical Microscope, Optical fluorescence microscope and stereomicroscope. It was observed huge variation of mechanical properties in both solid and composite materials, but in all cases there was considerable variability of strength data and in general the material without node was more resistant than with node. The ruptures mechanisms occurred most often in the parenchyma tissue by passing the fiber bundles and tend to follow the grain of the material by observing the rupture plane that only coincides with the plan designed to rupture when the specimen is done with precise consideration of grain orientation. The specimens manufactured with PVA adhesive and components with nodes responded satisfactorily to the low pressure bonding, while the specimens produced with internodes components performed better at high pressure. For specimens manufactured with resorcinol-formaldehyde adhesive the best gluing combination was given by the contact of outer laminas surfaces to each other. It was possible to observe the anchorage of the adhesive into the anatomical tissues by using optical microscopy and fluorescence optical microscopy. Glued laminated beams with composite cross section were tested in bending, but not failed by normal stresses, once there occurred only lateral instability during loading time. The I beams also showed low modulus of elasticity because the crush in the inferior flange was added by the measurement system to the bending deflection. In general the mechanical quality of the \"I\" joist can be considered very high with correct calculation of the moment of inertia of composite cross sections. The layers perpendicular to the beam axis both in web and in the flanges, were so efficient in absorbing the shear that there was no limitation of carrying load web-frange connection even with the beam working in a critical influence of high shear stresses.