Produção e avaliação de painéis de partículas de serragem e bagaço de cana com poliuretano a base de óleo de mamona

Among the goals for sustainable development in Brazil, studies have been conducted to better use of industrial and agricultural waste to promote adequate final disposal of these and generate new materials that minimize the exploitation and use of natural resources. In this work, the proposal is to make and evaluate boards with nominal density of 0.80 g.cm-3 using sugar cane bagasse, sawdust and polyurethane resin derived from castor oil. Thus, three treatments with different percentages of particles and 10% of PU-castor were proposed for the preparation of boards that were pressed with a pressure of 50 kgf.cm-2, a temperature of 100°C and a pressing time of ten minutes. The boards were evaluated for their physical properties (density, moisture content and swelling) and mechanical (static flexure and perpendicular traction) according to NBR 14810: 2-2013 and presented average values density of 936 to 937 kg.m-3, swelling after 24 hours of 5.0 to 7.2%, modulus of resistance to static bending of 22 to 23 MPa and perpendicular traction of 0.71 to 0.87 MPa. The results obtained with the tests indicate the great potential of use of sugarcane bagasse and sawdust to produce boards of high density particles.Dentre as metas para um desenvolvimento sustentável, no Brasil são realizados estudos para melhor aproveitamento de resíduos industriais e agrícolas de forma a promover adequada disposição final destes e gerar novos materiais que minimizem a exploração e o uso de recursos naturais. Neste trabalho, propõe-se confeccionar e avaliar painéis de partículas com densidade nominal de 0,80 g.cm-3 empregando-se bagaço de cana-de-açúcar, serragem e adesivo poliuretano bicomponente derivado de óleo de mamona. Assim, foram propostos três tratamentos com porcentagens diferentes de partículas e 10% de PU-Mamona para confecção de painéis que foram prensados com pressão de 50 kgf.cm-2, temperatura de 100°C e tempo de prensagem de dez minutos. Os painéis foram avaliados em suas propriedades físicas (densidade, umidade e inchamento) e mecânicas (flexão estática e tração perpendicular) de acordo com a NBR 14810:2-2013 e apresentaram valores médios de densidade de 936 a 937 kg.m-3, Inchamento após 24h de 5,0 a 7,2%, módulo de resistência à flexão estática de 22 a 23 MPa e resistência à tração perpendicular de 0,71 a 0,87 MPa. Os resultados obtidos com os ensaios indicam o grande potencial de utilização de bagaço de cana e serragem para produção de painéis de partículas de alta densidade

Produção de painéis de partículas de madeira com inclusão de poliestireno

The growth of human consumption has caused countless inconveniences to the environment, including the inappropriate disposal of inorganic materials with a long useful life. The incorporation of potential residues in the manufacture of wood-based particleboards presents itself as an alternative to this problem. This research by objective to evaluate the effects of replacing partial of wood particles of expanded polystyrene particles bonded with mammon bean polyurethane. Wood particles (50% pine + 50% Eucalyptus) were replaced by 25 and 50% (by mass) of expanded polystyrene particles in order to improve the physical and mechanical properties of panels manufactured with 5% polyurethane adhesive based on mammon oil. Composites manufactured with 50% of polystyrene particles resulted in the best values of the evaluated physical and mechanical properties (ABNT NBR 14810 and EN 312), designating credibility to the production of panels with the partial replacement of wood particles by polystyrene particles.O crescimento do consumo humano tem causado inúmeros transtornos para o meio ambiente, inclusive pelo descarte inapropriado de materiais inorgânicos de longa vida útil. A incorporação de potenciais resíduos na fabricação de painéis aglomerados à base de madeira se apresenta como uma alternativa a essa problemática. Esta pesquisa teve por objetivo avaliar os efeitos da substituição parcial de partículas de madeira por partículas de poliestireno expandido aglutinados com poliuretano de mamona. As partículas de madeira (50% de Pinus + 50% de Eucalipto) foram substituídas por 25 e por 50% (em massa) de partículas de poliestireno expandido visando aprimorar as propriedades físicas e mecânicas de painéis fabricados com 5% de adesivo poliuretano à base de óleo de mamona. Os compósitos fabricados com 50% de partículas de poliestireno resultaram nos melhores valores das propriedades físicas e mecânicas avaliadas (ABNT NBR 14810 e EN 312), designando credibilidade à produção de painéis com a substituição parcial de partículas de madeira por partículas de poliestireno

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Confecção e avaliação de painéis de partículas de madeira de média densidade com aproveitamento de resíduos industriais

No Brasil intensificam-se os estudos visando o aproveitamento dos subprodutos industriais com a justificativa de que propiciarão proteção ao meio ambiente, pois, seu aproveitamento poderá agregar valor a novos produtos com interesse comercial e poderão minimizar a exploração e o uso de recursos naturais. Este trabalho se propõe avaliar a influência da composição granulométrica no desempenho de painéis de partículas de madeira de média densidade de acordo com a ABNT NBR14810-1 e 2:2013, pois, em estudos orientados pelo autor, nas avaliações realizadas em painéis de partículas de madeira de marcenarias e de fábricas de moveis com emprego de adesivo poliuretano derivado de óleo de mamona (PU-Mamona) foi identificado que, para melhorar as propriedades dos painéis, seria necessário melhorar a composição granulométrica do resíduo utilizado, neste sentido, este trabalho, propôs cinco tratamentos com misturas diferentes de partículas de madeira e adição de partículas de bagaço de cana-de-açúcar. Em seguida foram confeccionados painéis de partículas com as misturas propostas nos tratamento e realizadas avaliações para a verificação das propriedades físicas e mecânicas dos painéis. Os resultados obtidos evidenciaram significativa melhoria das propriedades físicas e mecânicas dos painéis, sendo possível indicar o aproveitamento dos resíduos estudados para a produção de painéis de madeira de média densidade do tipo P2 segundo a ABNT NBR 14810-1 e 2:201

Avaliação da distribuição da densidade em MDF a partir da técnica da onda de ultra-som

The goal of this research was to determine the density distribution in medium density fiberboard (MDF), manufactured with polyurethane derived from castor oil using, ultrasonic wave technique. The equipment used in this test is Steinkamp BP7 with plan and exponential transducers, both with 45 kHz frequencies, located in several zones on the plate in order to determine wave ultrasonic velocity. The Pinus caribaea and Eucalyptus grandis fiberboard were manufactured in the quality control and products development laboratory of Duratex with 500 mm long, 500 mm large, 8 and 15 mm of thickness. Three MDF for each fiber specimen and thickness were fabricated, totalizing twelve plates tested. The MDF were produced with 5% polyurethane addition, in temperature of 160°C, tension press of 53 bars and addition of moisture content of 12%. For determination of fiberboard density, samples were extracted from the same zones where the wave ultrasonic velocity was determined. In this case, DAX-Ray equipment was used. Statistical analysis shows good agreement with wave ultrasonic velocity and the density profile, validating the application of non-destructive technique in order to determine the density profile of MDF's