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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

Using fungicides or combinations of fungicides to provide mold and decay fungal protection to OSB

Choi, Baek Yong 05 1900 (has links)
The use of wood-based composites has increased dramatically over the last two decades due to a number of factors. One reason is that Oriented Strand Board (OSB) is being increasingly utilized in residential applications in place of plywood. However, the use of OSB in residential construction is often limited because of its susceptibility to attack by biological pathogens such as mold and decay fungi. The environmental conditions that exist in certain use categories can be so adverse that the performance of these composites is negatively affected. This study was divided into two parts. The first phase examined the effectiveness of fungicides or combinations of fungicides (including some metal-containing preservatives) for enhancing the mold resistance of strandboard. During the second part of the study, preliminaryexperiments investigated the effectiveness of fungicides or combinations of fungicides using anagar-block test to estimate the preservative toxic threshold retention. The compatibility of the fungicide on the resin curing was studied by measuring change in the resin gelation and viscosity. After these screening experiments were completed, large size boards were prepared and mechanical and decay resistance properties were examined. It was found that mold and decay resistance properties of strandboard directly were related with the biocide type and its concentration. Greater protection of the strandboard was achieved with an increase in preservative retention levels. However, due to the relatively high cost of non-metallic (organic) preservatives, it is important to find the minimum amount of preservative that can protect the OSB against mold and decay fungi. One method of reducing the cost and increasing efficacy is to combine different fungicides to determine whether synergism exists. Even if synergism does not occur, it may reduce the overall cost by combining a less expensive biocide with a smaller amount of a more expensive biocide wheretheir biocidal efficacy complements each other. In addition, it is important to understand that high retention of preservative may also cause negative effects on the mechanical properties of strandboard. This maybe noticeable of the high retention level of the biocide when a greater negative effect on the internal bonding (IB) strength may be recorded. Lower IB strength for treated strandboard may be attributed to the formulation of chemical residue in the wood surface, which may interfere with the reaction between wood and phenol formaldehyde (PF) resin. Surface-active agents in the preservative may also cause the PF resin to over-penetrate into wood decreasing bond strength. Increasing moisture content of strands by the introduction of an emulsified aqueous biocide solution, may cause dilution of the resin, and reduced bonding. It should also be noted that high retention of preservative which cause a change in the viscosity and gelation time of PF resins would be problematic for the operation of an OSB plant. For viscosity change, it could significantly affect the flow properties of the resin on the wood furnish and its atomization as it is spraying onto the wood furnish. In addition, it may require further modification to the equipment that supplies the resin to the spray nozzle. For changes in the gelation time, this may require changes to the press time at the OSB plant.
2

Using fungicides or combinations of fungicides to provide mold and decay fungal protection to OSB

Choi, Baek Yong 05 1900 (has links)
The use of wood-based composites has increased dramatically over the last two decades due to a number of factors. One reason is that Oriented Strand Board (OSB) is being increasingly utilized in residential applications in place of plywood. However, the use of OSB in residential construction is often limited because of its susceptibility to attack by biological pathogens such as mold and decay fungi. The environmental conditions that exist in certain use categories can be so adverse that the performance of these composites is negatively affected. This study was divided into two parts. The first phase examined the effectiveness of fungicides or combinations of fungicides (including some metal-containing preservatives) for enhancing the mold resistance of strandboard. During the second part of the study, preliminaryexperiments investigated the effectiveness of fungicides or combinations of fungicides using anagar-block test to estimate the preservative toxic threshold retention. The compatibility of the fungicide on the resin curing was studied by measuring change in the resin gelation and viscosity. After these screening experiments were completed, large size boards were prepared and mechanical and decay resistance properties were examined. It was found that mold and decay resistance properties of strandboard directly were related with the biocide type and its concentration. Greater protection of the strandboard was achieved with an increase in preservative retention levels. However, due to the relatively high cost of non-metallic (organic) preservatives, it is important to find the minimum amount of preservative that can protect the OSB against mold and decay fungi. One method of reducing the cost and increasing efficacy is to combine different fungicides to determine whether synergism exists. Even if synergism does not occur, it may reduce the overall cost by combining a less expensive biocide with a smaller amount of a more expensive biocide wheretheir biocidal efficacy complements each other. In addition, it is important to understand that high retention of preservative may also cause negative effects on the mechanical properties of strandboard. This maybe noticeable of the high retention level of the biocide when a greater negative effect on the internal bonding (IB) strength may be recorded. Lower IB strength for treated strandboard may be attributed to the formulation of chemical residue in the wood surface, which may interfere with the reaction between wood and phenol formaldehyde (PF) resin. Surface-active agents in the preservative may also cause the PF resin to over-penetrate into wood decreasing bond strength. Increasing moisture content of strands by the introduction of an emulsified aqueous biocide solution, may cause dilution of the resin, and reduced bonding. It should also be noted that high retention of preservative which cause a change in the viscosity and gelation time of PF resins would be problematic for the operation of an OSB plant. For viscosity change, it could significantly affect the flow properties of the resin on the wood furnish and its atomization as it is spraying onto the wood furnish. In addition, it may require further modification to the equipment that supplies the resin to the spray nozzle. For changes in the gelation time, this may require changes to the press time at the OSB plant.
3

Using fungicides or combinations of fungicides to provide mold and decay fungal protection to OSB

Choi, Baek Yong 05 1900 (has links)
The use of wood-based composites has increased dramatically over the last two decades due to a number of factors. One reason is that Oriented Strand Board (OSB) is being increasingly utilized in residential applications in place of plywood. However, the use of OSB in residential construction is often limited because of its susceptibility to attack by biological pathogens such as mold and decay fungi. The environmental conditions that exist in certain use categories can be so adverse that the performance of these composites is negatively affected. This study was divided into two parts. The first phase examined the effectiveness of fungicides or combinations of fungicides (including some metal-containing preservatives) for enhancing the mold resistance of strandboard. During the second part of the study, preliminaryexperiments investigated the effectiveness of fungicides or combinations of fungicides using anagar-block test to estimate the preservative toxic threshold retention. The compatibility of the fungicide on the resin curing was studied by measuring change in the resin gelation and viscosity. After these screening experiments were completed, large size boards were prepared and mechanical and decay resistance properties were examined. It was found that mold and decay resistance properties of strandboard directly were related with the biocide type and its concentration. Greater protection of the strandboard was achieved with an increase in preservative retention levels. However, due to the relatively high cost of non-metallic (organic) preservatives, it is important to find the minimum amount of preservative that can protect the OSB against mold and decay fungi. One method of reducing the cost and increasing efficacy is to combine different fungicides to determine whether synergism exists. Even if synergism does not occur, it may reduce the overall cost by combining a less expensive biocide with a smaller amount of a more expensive biocide wheretheir biocidal efficacy complements each other. In addition, it is important to understand that high retention of preservative may also cause negative effects on the mechanical properties of strandboard. This maybe noticeable of the high retention level of the biocide when a greater negative effect on the internal bonding (IB) strength may be recorded. Lower IB strength for treated strandboard may be attributed to the formulation of chemical residue in the wood surface, which may interfere with the reaction between wood and phenol formaldehyde (PF) resin. Surface-active agents in the preservative may also cause the PF resin to over-penetrate into wood decreasing bond strength. Increasing moisture content of strands by the introduction of an emulsified aqueous biocide solution, may cause dilution of the resin, and reduced bonding. It should also be noted that high retention of preservative which cause a change in the viscosity and gelation time of PF resins would be problematic for the operation of an OSB plant. For viscosity change, it could significantly affect the flow properties of the resin on the wood furnish and its atomization as it is spraying onto the wood furnish. In addition, it may require further modification to the equipment that supplies the resin to the spray nozzle. For changes in the gelation time, this may require changes to the press time at the OSB plant. / Forestry, Faculty of / Graduate
4

Optimalizace lisovací křivky na základě měření změn tlaku a teploty v desce v průběhu lisování

Huvar, Marian January 2010 (has links)
No description available.
5

Vliv tepelné úpravy vybraných materiálů na vybrané fyzikální a mechanické vlastnosti dřeva

Rosendorf, Jiří January 2011 (has links)
No description available.
6

Produção e avaliação do desempenho de painéis de partículas orientadas (OSB) de Pinus sp com inclusão de telas metálicas / Production and performance evaluation of Pinus sp oriented strandboard (OSB) with metallic gauze inclusion

Souza, Amós Magalhães de 10 July 2012 (has links)
O OSB é um produto derivado da madeira desenvolvido nos Estados Unidos em 1970. É definido como um painel de partículas orientadas, as quais são distribuídas em camadas múltiplas de uma forma predeterminada. À época, o OSB foi criado para substituir o painel de madeira compensada. Todavia, geralmente suas propriedades na flexão estática são inferiores. A proposta principal deste trabalho foi produzir e analisar o desempenho de painéis OSB de Pinus sp e resina poliuretana à base de óleo mamona com inclusão de telas metálicas, objetivando acréscimo nas propriedades de resistência e de rigidez na flexão estática. A produção seguiu o processo laboratorial, consistindo em gerar as partículas, distribuir o adesivo, confeccionar o colchão e prensar à temperatura de 100°C por 10 minutos. O teor de resina adotado foi de 12% tendo como base a massa seca das partículas. Os painéis foram confeccionados com três camadas, as externas tendo direção paralela ao comprimento da chapa e a interna com distribuição randômica. A proporção face/miolo/face foi na faixa de 20:60:20. Com base nas recomendações de documentos normativos brasileiros e europeus foram realizados ensaios de flexão estática, de onde foram determinados os módulos de ruptura (MOR), e módulo de elasticidade (MOE), ensaios de arrancamento de parafusos, adesão interna, teor de umidade, absorção de água, inchamento em espessura e determinação da densidade aparente. Os resultados apontam a eficiência dos painéis OSB produzidos quando comparadas suas propriedades com os valores mínimos exigidos pelas normas e valores encontrados na literatura para painéis desta natureza. A utilização da tela metálica se mostrou não necessária, dada a pouco relevante diferença de MOE e MOR entre os painéis com e sem a tela. / OSB is a wood based product developed in the United States, since 1954. It\'s defined as oriented particles panels, which are distributed in multiple layers of a predetermined shape. At the time, the OSB was created to replace the plywood panel, but usually its bending properties are inferior. The main purpose of this study was to produce and analyze the performance of OSB from Pinus sp and castor oil based polyurethane resin with inclusion of metallic gauzes, aiming to increase strength and stiffness properties in static bending. Panel production followed laboratory process, consisting of particles generation, adhesive distribution, mattress making and a pressing in 100ºC temperature for 10 minutes. The resin content was set at 12% based on particles dry weight. Panels were produced with three layers: the outers with strands in direction parallel to the panel length; internal in randomized distribution. Face/core/face particle proportion was in range of 20:60:20. Based on Brazilian and European codes recommendations, several tests were performed to determine: modulus of rupture (MOR) and modules of elasticity (MOE), in static bending; screw pullout; internal adhesion; moisture content; water absorption; thickness swelling and density. Results showed efficiency of OSB produced comparing their properties with basic codes requirements the standards and literature values for such panels. The use of metallic gauze has been shown not necessary, because of small relevant difference between MOE and MOR for panels with and without gauze inclusion.
7

Painéis OSB com madeira Schizolobium amazonicum e resina poliuretana à base de óleo de mamona: viabilidade técnica de produção / OSB wood panel of Schizolobium amazonicum with polyurethane resin based-castor oil: the technical feasibility of production

Ferro, Fabiane Salles 14 February 2013 (has links)
O Paricá (Schizolobium amazonicum) é uma espécie nativa do Brasil com ampla distribuição geográfica. Sua plantação e utilização estão em constante crescimento, devido às características apresentadas pela espécie. A principal utilização da madeira de Paricá tem sido a fabricação de lâminas de compensados. Entretanto, esses painéis experimentam redução de oferta, devido sua substituição por OSB. O presente trabalho teve como objetivo principal avaliar a viabilidade técnica de produção de painéis OSB fabricados com partículas de madeira da espécie Schizolobium amazonicum e resina poliuretana à base de óleo de mamona. Com a finalidade de proporcionar maior durabilidade e qualidade a estes painéis, também foi avaliada a influência do tratamento das partículas com preservante CCA e CCB e a variação de três teores de adesivo (8, 10 e 12%). O desempenho dos painéis para as propriedades de inchamento em espessura e absorção de água após períodos de 2 e 24 horas de imersão, módulo de elasticidade (MOE) e módulo de ruptura (MOR) para as direções paralela e perpendicular à orientação das partículas e adesão interna, foram avaliados segundo o documento normativo europeu EN 300 (2006). A resistência ao arrancamento de parafuso de face e de topo foi investigada de acordo com a norma brasileira ABNT NBR 14810-2 (2006). Os resultados apontaram excelentes propriedades físico-mecânicas para os painéis OSB produzidos neste estudo, quando comparados com os valores mínimos recomendados pelas normas citadas e com os valores encontrados na literatura, para painéis desta natureza com finalidades comerciais. Desta maneira ficou comprovada a viabilidade da utilização da espécie Paricá, quando tratada com preservantes CCA e CCB, e quando utilizada \"in natura\", juntamente com a resina poliuretana à base de óleo de mamona na fabricação de painéis OSB. / Paricá (Schizolobium amazonicum) is a Brazilian native wood specie, with wide geographic distribution. Their plantation and utilization are constantly growing due to the features presented by the specie. Primary use of wood has been in manufacture of plywood sheets. However, these panels present a gradual offer reduction, being replaced by OSB. This study aimed to assess the technical feasibility of producing OSB, using Paricá particles and castor oil based polyurethane resin. With the purpose of improve durability and quality of these panels, effect of treating the particles with preservative CCA and CCB and the variation of three levels of adhesive (8%, 10% and 12%) were also evaluated. OSB performance in thickness swelling and water absorption after periods of 2 to 24 hours of immersion, modulus of elasticity (MOE) and modulus of rupture (MOR), directions parallel and perpendicular to the particles orientation and internal bonding were evaluated according to the European normative document EN 300 (2006). Pullout strength of the screw (face and top) was investigated according to norm ABNT NBR 14810 (2006). The results showed excellent physical and mechanical properties for the OSB produced in this study, when compared with the minimum recommended by the standards and the values cited in the literature, such panels for commercial purposes. Thus it was proved the feasibility of using Paricá specie when treated with preservatives CCA and CCB, and when used \"in natura\" with castor-oil based polyurethane resin in OSB production.
8

Utredning om andra tillämpningar än byggstommar för profilpressade träkompositer av OSB-material.

Nyberg, Kjell January 2008 (has links)
<p><p>Newbeam Sweden AB är ett ganska ungt företag som genom deras patent har börjat kunna pressa unika träkompositer i 3 dimensioner. Företaget ligger i startgroparna med sin första tillverkningslina som skall öppnas i Söderhamn, Hälsingland.</p><p>De själva har satsat mycket mot byggnadsindustrin. Min uppgift i detta arbete har varit att undersöka andra marknader med deras profi lpressade träkompositer som grund. Inriktningen blev butiksinredningar som ett resultat av researcharbetet som gjordes.</p><p>Intervjuer och undersökningar gav en bild av hur viktigt det är med användarvänlighet samt enkelhet och de två orden blev mitt motto arbetet igenom.</p><p>Resultatet av detta kom att bli lite mer än bara butiksinredningar.</p></p> / <p>Newbeam Sweden AB is a fairly young company which with their new patent are able to press unique wood composite in 3 dimensions. The company are about to start thier fi rst manufacturing line in Söderhamn, Hälsingland.</p><p>Their main target is to make components for house-constructions. My objective in this project has been to investigate other fi elds of interest with their 3 dimensional wood composite beams as buildingblocks.</p><p>From the research that was made, a focus towards stores and their furnish equipment came to be the concentration. Interviews and investigations gave a good picture of how important it is to off er easy-to-use and simplicity in constructions. Theese words became my motto during this project.</p><p>The result of my work came to be a little more than furnish equipment for stores.</p>
9

Utredning om andra tillämpningar än byggstommar för profilpressade träkompositer av OSB-material.

Nyberg, Kjell January 2008 (has links)
Newbeam Sweden AB är ett ganska ungt företag som genom deras patent har börjat kunna pressa unika träkompositer i 3 dimensioner. Företaget ligger i startgroparna med sin första tillverkningslina som skall öppnas i Söderhamn, Hälsingland. De själva har satsat mycket mot byggnadsindustrin. Min uppgift i detta arbete har varit att undersöka andra marknader med deras profi lpressade träkompositer som grund. Inriktningen blev butiksinredningar som ett resultat av researcharbetet som gjordes. Intervjuer och undersökningar gav en bild av hur viktigt det är med användarvänlighet samt enkelhet och de två orden blev mitt motto arbetet igenom. Resultatet av detta kom att bli lite mer än bara butiksinredningar. / Newbeam Sweden AB is a fairly young company which with their new patent are able to press unique wood composite in 3 dimensions. The company are about to start thier fi rst manufacturing line in Söderhamn, Hälsingland. Their main target is to make components for house-constructions. My objective in this project has been to investigate other fi elds of interest with their 3 dimensional wood composite beams as buildingblocks. From the research that was made, a focus towards stores and their furnish equipment came to be the concentration. Interviews and investigations gave a good picture of how important it is to off er easy-to-use and simplicity in constructions. Theese words became my motto during this project. The result of my work came to be a little more than furnish equipment for stores.
10

"SIENA" / "WALL"

Navickienė, Justina 02 September 2010 (has links)
Mano diplominis darbas pavadinimu ,, Siena“. Kiekvieną dieną žmogus nor÷damas to ar ne, atsik÷lęs ryte pirmiausia išvysta kambario sienas. Taip pat ir mieste, gamtoje, neišvengiamai matome, tvoras, pertvaras, sienas. Vienos jų naujos, ką tik pastatytos, kitos nuo amžiaus pasenusios. Savo diplominį darbą sieju su aukštomis tarsi sienos tvoromis, kuriomis aptvertos statybų teritorijos, apleisti namai. Neretai tokios sienos ,,papuoštos“ grafiti raštais ar visaip aprašin÷tos. Diplominį darbą sudaro dvi dalys: praktinis darbas ir teorinis aprašas. Praktinį darbas sudaro vienas darbas. 1620mm x 2500mm, OSB plokšt÷, aliejus. Teorin÷je dalyje apžvelgiu temos paiešką, darbo priemones, darbo eigą. / My thesis title ,,Wall“. Every day people order it or not, first rose up in the morning departs the room walls. Also in the city, naturally, inevitably, we see fences, walls. Some of them, new matches are constructed, the other from old age. Their associate degree work with a high wall like a fence that enclosed the construction site, abandoned houses. Often these walls, decorated with graffiti letters or dying painted. Thesis consists of two parts: practical work and theoretical description. Practical work is a job. 1620mm x 2500mm, OSB board, oil. I look in the theoretical topics search, work tools, work in progress.

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