Realizou-se, no contexto deste trabalho, o estudo de espécies tropicais de madeira e a qualificação destas a partir de suas características físicas, de resistência e rigidez. Os ensaios para a determinação das propriedades foram realizados no Laboratório de Madeiras e de Estruturas de Madeira, do Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, seguindo as recomendações do anexo B da NBR 7190/1997 - Projeto de Estruturas de Madeira. O objetivo fundamental é gerar informações que possam fornecer suporte para um direcionamento e perspectiva de novas possibilidades de aplicação na construção civil: construção de estruturas para diferentes finalidades (coberturas, pontes, cimbramentos); industriais para componentes de edificações (pisos, caixilhos); armazenamento; obras portuárias; entre outras. / It was realized, in the context of this work, a study about tropical wood species and their qualification, based on the physical and mechanical properties. The tests to the determination of such properties were realized in Wood and Timber Structures Laboratory, Structural Engineering Departament, São Carlos Engineering School, according to the recommendations of the Annex B, NBR 7190/1997 - Timber Structures Design. The mean subject is to generate information to permit new application in civil construction: structures for different purposes (roofs, bridges, formwork); industrial to building components; storage; among others.

Realizou-se, no contexto deste trabalho, o estudo de espécies tropicais de madeira e a qualificação destas a partir de suas características físicas, de resistência e rigidez. Os ensaios para a determinação das propriedades foram realizados no Laboratório de Madeiras e de Estruturas de Madeira, do Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, seguindo as recomendações do anexo B da NBR 7190/1997 - Projeto de Estruturas de Madeira. O objetivo fundamental é gerar informações que possam fornecer suporte para um direcionamento e perspectiva de novas possibilidades de aplicação na construção civil: construção de estruturas para diferentes finalidades (coberturas, pontes, cimbramentos); industriais para componentes de edificações (pisos, caixilhos); armazenamento; obras portuárias; entre outras. / It was realized, in the context of this work, a study about tropical wood species and their qualification, based on the physical and mechanical properties. The tests to the determination of such properties were realized in Wood and Timber Structures Laboratory, Structural Engineering Departament, São Carlos Engineering School, according to the recommendations of the Annex B, NBR 7190/1997 - Timber Structures Design. The mean subject is to generate information to permit new application in civil construction: structures for different purposes (roofs, bridges, formwork); industrial to building components; storage; among others.

Yes / This study investigates the physical and mechanical properties of 12 biomass wood pellet samples utilised in a power generation, focusing on their implications for energy release and carbon emissions during combustion. Through comprehensive analysis involving bulk density measurements, compression tests, moisture analysis, calorimetry and controlled burning experiments, significant correlations among key properties are identified. Pellets with densities above 1100 kg/m3 demonstrate superior mechanical durability and strength, achieving maximum strengths of 0.6 to 0.8 kN with durability exceeding 99.4%. Optimal moisture content, typically between 6 and 7% is crucial for maximising density, bulk density, mechanical durability and fracture resistance, ensuring robust pellet structure and performance. The research underscores the impact of pellet dimensions, highlighting those longer lengths, > 12 mm enhance durability, while larger diameters > 8 mm exhibit reduced durability. Elemental analysis focusing on calcium, silicon and potassium plays a critical role in predicting and managing combustion system fouling, potentially reducing operational costs. Moreover, the study emphasises the significant influence of oxygen levels during combustion on CO2 emissions, achieving optimal results with moisture content in the 7–8% range for maximum higher heating value (HHV). The moisture content in the 14–15% range represents the lowest CO2 emission. The findings underscore the intricacy of the system and the interplay of parameters with one another. In accordance with the priority of each application, the selection of parameters warrants careful consideration. / This work was supported by the UK Carbon Capture and Storage Research Community (UKCCSRC) and the Engineering and Physical Sciences Research Council (EPSRC) through the UKCCSRC Flexible Funding Call 2022.

No description available.

O tratamento térmico da madeira (ou termorretificação) é realizado com o aquecimento da madeira em faixas de temperaturas inferiores à carbonização, até 280ºC. O objetivo desta tecnologia é melhorar as propriedades da madeira e, desta forma, proporcionar a obtenção de produtos com maior valor agregado. Neste trabalho, avaliou-se o comportamento em peças estruturais das espécies Eucalipto citriodora (Corymbia citriodora) e Pinus taeda, tratadas termicamente nas temperaturas de 160, 180, 200, 220 e 240ºC e, para o pínus, até a temperatura de 260ºC. Os ensaios experimentais realizados para a madeira tratada termicamente foram de classificação visual, obtenção de suas propriedades químicas, físicas, mecânicas (resistência e rigidez), entomológicas e com fungos. Quanto à análise química, foi identificado redução nos teores de extrativos e hemiceluloses, após termorretificação das amostras, e aumento no teor de celulose e lignina. A densidade aparente e a propriedade de inchamento das madeiras reduziram com o aumento da temperatura, e a permeabilidade a gás aumentou para o eucalipto. As mudanças nas propriedades colorimétricas das madeiras levaram ao escurecimento, devido à degradação dos seus principais componentes químicos, principalmente as hemiceluloses. De uma maneira geral, as propriedades de resistência (à compressão, à flexão, à tração e ao cisalhamento paralelo às fibras) das madeiras diminuiram e as propriedades de rigidez (módulo de elasticidade na compressão Eco e o MOE) aumentaram ao longo do tratamento com calor. A determinação dos valores característicos de resistência para cálculos estruturais foram adequados quando comparados à norma brasileira ABNT NBR 7190/97. O tratamento térmico proporcionou a proteção da madeira de Eucalipto citriodora quando ela foi exposta ao ataque de cupins subterrâneos Nasutitermes sp., de acordo com os ensaios de alimentação forçada, e das madeiras de E. citriodora e Pinus taeda, quando expostas ao fungo de podridão mole (Paecilomyces variotti). / Heat treatment of wood (or thermal rectification) is performed by heating wood below carbonization temperature, up to 280ºC. The aim of this technology is to improve the wood properties and thus to obtain products with higher added value. In this study, we evaluate the behavior of structural pieces of two species: Eucalyptus citriodora (Corymbia citriodora) and Pinus taeda, thermally treated at temperatures of 160, 180, 200, 220 e 240ºC, and pine up to the temperature of 260ºC. The experimental analyses to thermally treated wood were visual grading, chemical, physical, mechanical (strength and stiffness) and durability. Regarding chemical analysis, there was a reduction in the extractive and hemicellulose contents, while and the cellulose and lignin content increased; density and swelling properties decreased with increasing temperature, and the air permeability increased to eucalyptus. Changes in the colorimetric properties of wood caused the species in the study to become darker due to degradation of chemical components, mainly hemicellulose. In general, the strength properties (compression, bending, tension and shear parallel to the grain) of wood reduced and the stiffness properties (elasticity modulus by compression (Eco) and MOE) improved along thermal treatment. The determination of characteristic values of strength to structural calculations was adequate when compared to the Brazilian norm ABNT NBR 7190/97. It was observed that thermal treatment provided protection of wood of Eucalyptus citriodora from subterranean termites attack Nasutitermes sp., in the force-feeding test and Eucalyptus citriodora and Pinus taeda on soft rot fungi Paecilomyces variotti.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-13T12:25:00Z No. of bitstreams: 1 2016 - Sheyla Moreira Gon?alves.pdf: 3716146 bytes, checksum: eaee6e62414cd3d497528f597f1abab5 (MD5) / Made available in DSpace on 2016-10-13T12:25:00Z (GMT). No. of bitstreams: 1 2016 - Sheyla Moreira Gon?alves.pdf: 3716146 bytes, checksum: eaee6e62414cd3d497528f597f1abab5 (MD5) Previous issue date: 2016-02-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The use of active packaging incorporated with natural antimicrobials as essential oils (EOs) for food preservation is a modern concept for the food industry. The objective of this study was to characterize cellulose acetate film (CA) incorporated with EOs and their combinations and/or added plasticizer, evaluating the influence of additives on the behavior of these materials. It is characterized as the thickness of the films, visual aspect, chemical structure, surface, mechanical strength, water vapor rate of transmission (WVRT) and antimicrobial activity. Through technique "casting" were obtained films incorporated with 50% (w/v) of EOs oregano or cinnamon or sweet fennel or combinations thereof and/or glycerol (5, 10, 20 and 30% (w/v)). Having as controls only films containing 50% (w/v) glycerol, and CA pure film, a total 41 treatments. The incorporation of EOs did not change the thickness and transparency of the films, but it reduced the WVRT. The color parameters L *, a* and b* were affected by the incorporation with EOs and/or glycerol the films exhibited clear with different colors compared with the AC pure film. Incorporating the most EOs cause increased tensile strength (TS) of the modulus of elasticity (ME) and reduced elongation at break (EB), except for the film with fennel EO (FEO) who presented plasticizer power differing from the other for all the evaluated mechanical parameters. The drilling force (DF) has increased to most films EOs incorporated with the exception of the film incorporated with the three EOs. The scanning electron microscopy (SEM) images revealed that most of the EOs and their combinations did not cause changes in the surface and cross-sectional area of the films, except the film with FEO. In the spectra of infrared spectroscopy with Fourier transform (FTIR), it observed that the interactions between the polymer matrix and most EOs were similar except for the film with FEO. As for the antibacterial efficiency in vitro, only the film incorporated with FEO showed no efficacy against Staphylococcus aureus (Gram +) and Escherichia coli (Gram +). It was observed that glycerol causes increased thickness and WVRT the AC films, however, the active films with EOs does not modify the parameter to most treatments. Transparency was not affected for most films. The addition of glycerol for most films incorporated with EOs caused reduction of TS, the ME and increased EB and DF. From the SEM pictures it can be observed that the glycerol promoted the emergence of porous structures, networked or compact, depending on the EO concentration and glycerol. The FTIR spectral showed that glycerol has different interactions, depending on the embedded EOs. The antibacterial efficiency of films with EO oregano or cinnamon or oregano more cinnamon has been improved with the presence of glycerol, while the others were not affected. In the face of changes in functional properties observed, it appears that with the additivation materials it is necessary to characterize them to define their applicability / O emprego de embalagens ativas incorporadas com antimicrobianos naturais, como os ?leos essenciais (OEs) para conserva??o de alimentos, representa um conceito moderno para a ind?stria aliment?cia. Objetivou-se neste trabalho caracterizar filmes de acetato de celulose (AC) incorporados com OEs e suas combina??es e/ou adi??o de plastificante, avaliando as influ?ncias da aditiva??o no comportamento f?sico e mec?nico destes materiais. Caracterizou-se os filmes quanto ? espessura, aspectos visuais, estrutura qu?mica, superf?cie, resist?ncia mec?nica, taxa de transmiss?o ao vapor de ?gua (TTVA) e atividade antimicrobiana. Atrav?s da t?cnica ?casting? foram obtidos filmes incorporados com 50% (p/v) de OEs de or?gano, canela, funcho doce ou suas combina??es e/ou glicerol (5, 10, 20 e 30% (p/v)). Tendo como controles filmes contendo somente 50% (p/v) de glicerol, e filme de AC puro, totalizando 41 tratamentos. A incorpora??o de OEs n?o modificou a espessura e transpar?ncia dos filmes, por?m causou redu??o da TTVA. Os par?metros de cor L*, a* e b* foram afetados pela incorpora??o de OEs e/ou glicerol tendo os filmes apresentado-se claros com diferentes cores em compara??o com o filme de AC puro. A incorpora??o da maioria dos OEs causou aumento da resist?ncia ? tra??o (RT), do m?dulo de elasticidade (ME) e redu??o do alongamento na ruptura (AR), com exce??o para o filme com OE de funcho (OEF) que apresentou poder plastificante diferindo dos demais para todos os par?metros mec?nicos avaliados. A for?a de perfura??o (FP) aumentou para a maioria dos filmes incorporados com OEs, a exce??o do filme incorporado com os tr?s OEs. As imagens de microscopia eletr?nica de varredura (MEV) revelaram que a maioria dos OEs e suas combina??es n?o causaram mudan?as na superf?cie e regi?o transversal dos filmes, a exce??o do filme com OEF. Nos espectros da espectroscopia no infravermelho com transformada de Fourier (FTIR), notou-se que as intera??es entre a matriz polim?rica e a maioria dos OEs foram semelhantes, com exce??o para o filme com OEF. Quanto ? efici?ncia antibacteriana in vitro, somente o filme incorporado com OEF n?o apresentou efetividade contra Staphylococcus aureus (Gram +) e Escherichia coli (Gram -). Foi observado que o glicerol causou aumento da espessura e TTVA nos filmes de AC, por?m, nos filmes ativos com OEs n?o modificou o par?metro para maioria dos tratamentos. A transpar?ncia n?o foi afetada para a maioria dos filmes. A adi??o de glicerol para a maioria dos filmes incorporados com OEs causou redu??o da RT, do ME e aumento do AR e FP. Pelas imagens do MEV observa-se que o glicerol promoveu o surgimento de estruturas porosas, em rede ou compactas, dependendo do OE e concentra??o de glicerol. Os espectros da FTIR demonstraram que o glicerol apresentou diferentes intera??es, dependendo do OE incorporado. A efici?ncia antibacteriana dos filmes com OE de or?gano ou canela ou or?gano mais canela foi melhorada com a presen?a de glicerol, enquanto os demais n?o sofreram influ?ncia. Diante das varia??es nas propriedades funcionais observadas, verifica-se que com a aditiva??o dos materiais ? necess?rio caracteriza??o para definir sua aplicabilidade

O tratamento térmico da madeira (ou termorretificação) é realizado com o aquecimento da madeira em faixas de temperaturas inferiores à carbonização, até 280ºC. O objetivo desta tecnologia é melhorar as propriedades da madeira e, desta forma, proporcionar a obtenção de produtos com maior valor agregado. Neste trabalho, avaliou-se o comportamento em peças estruturais das espécies Eucalipto citriodora (Corymbia citriodora) e Pinus taeda, tratadas termicamente nas temperaturas de 160, 180, 200, 220 e 240ºC e, para o pínus, até a temperatura de 260ºC. Os ensaios experimentais realizados para a madeira tratada termicamente foram de classificação visual, obtenção de suas propriedades químicas, físicas, mecânicas (resistência e rigidez), entomológicas e com fungos. Quanto à análise química, foi identificado redução nos teores de extrativos e hemiceluloses, após termorretificação das amostras, e aumento no teor de celulose e lignina. A densidade aparente e a propriedade de inchamento das madeiras reduziram com o aumento da temperatura, e a permeabilidade a gás aumentou para o eucalipto. As mudanças nas propriedades colorimétricas das madeiras levaram ao escurecimento, devido à degradação dos seus principais componentes químicos, principalmente as hemiceluloses. De uma maneira geral, as propriedades de resistência (à compressão, à flexão, à tração e ao cisalhamento paralelo às fibras) das madeiras diminuiram e as propriedades de rigidez (módulo de elasticidade na compressão Eco e o MOE) aumentaram ao longo do tratamento com calor. A determinação dos valores característicos de resistência para cálculos estruturais foram adequados quando comparados à norma brasileira ABNT NBR 7190/97. O tratamento térmico proporcionou a proteção da madeira de Eucalipto citriodora quando ela foi exposta ao ataque de cupins subterrâneos Nasutitermes sp., de acordo com os ensaios de alimentação forçada, e das madeiras de E. citriodora e Pinus taeda, quando expostas ao fungo de podridão mole (Paecilomyces variotti). / Heat treatment of wood (or thermal rectification) is performed by heating wood below carbonization temperature, up to 280ºC. The aim of this technology is to improve the wood properties and thus to obtain products with higher added value. In this study, we evaluate the behavior of structural pieces of two species: Eucalyptus citriodora (Corymbia citriodora) and Pinus taeda, thermally treated at temperatures of 160, 180, 200, 220 e 240ºC, and pine up to the temperature of 260ºC. The experimental analyses to thermally treated wood were visual grading, chemical, physical, mechanical (strength and stiffness) and durability. Regarding chemical analysis, there was a reduction in the extractive and hemicellulose contents, while and the cellulose and lignin content increased; density and swelling properties decreased with increasing temperature, and the air permeability increased to eucalyptus. Changes in the colorimetric properties of wood caused the species in the study to become darker due to degradation of chemical components, mainly hemicellulose. In general, the strength properties (compression, bending, tension and shear parallel to the grain) of wood reduced and the stiffness properties (elasticity modulus by compression (Eco) and MOE) improved along thermal treatment. The determination of characteristic values of strength to structural calculations was adequate when compared to the Brazilian norm ABNT NBR 7190/97. It was observed that thermal treatment provided protection of wood of Eucalyptus citriodora from subterranean termites attack Nasutitermes sp., in the force-feeding test and Eucalyptus citriodora and Pinus taeda on soft rot fungi Paecilomyces variotti.

in english For their positive influence on mechanical and physical properties of the material, methods of severe plastic deformation are popular for quite some time today. Rotary swaging is one of them. With its simplicity and productivity, it has the potential for industrial use. It is a radial swaging of rods or tubes, which results in decreasing of their diameter. Influence of this method is researched on extruded rods made of magnesium alloy AZ31. Experiments are made on five samples of different degree of swaging (different diameter). This allows to research gradual evolution of properties during the swaging. Results show significant positive influence on grain size (and microstructure in general) of originally extruded rod. During swaging there is an evolution of material texture and increase in strength.

While using iron castings behind temperature of 500 oC namely at cyclic heat straining, degradation of structure and breaching iron castings. For this purpose introduce cast iron with content of Si and Mo. Focusing on improvement of SiMo51 for increased high-temmperature corrosion-and fatigue life in exhaust-gas temperatures up to 800 oC. Thesis set up survey types alloys, properties, and way of casting production.

Diploma thesis is focused on the description of the parameters of nonlinear material models of concrete, which are implemented in a computational system LS-DYNA, interacting with performance of nonlinear test calculations in system LS-DYNA on selected problems, which are formed mainly by simulations of tests of mechanical and physical properties of concrete in uniaxial compressive and tensile on cylinders with applying different boundary conditions and by simulation of bending slab, with subsequent comparison of some results of test calculations with results of the experiment. The thesis includes creation of appropriate geometric models of selected problems, meshing of these geometric models, description of parameters and application of nonlinear material models of concrete on selected problems, application of loads and boundary conditions on selected problems and performance of nonlinear calculations in a computational system LS-DYNA. Evaluation of results is made on the basis of stress-strain diagrams and load-displacement diagrams based on nonlinear calculations taking into account strain rate effects and on the basis of hysteresis curves based on nonlinear calculations in case of application of cyclic loading on selected problems. Verification of nonlinear material models of concrete is made on the basis of comparison of some results of test calculations with results obtained from the experiment.