Página 1 dos resultados de 191 itens digitais encontrados em 0.002 segundos

Alterações na estrutura anatômica da madeira de cavacos de eucalyptus grandis em três condições de desfibramento para a confecção de painéis MDF; Changes in the anatomical structure of eucalyptus grandis wood chips in three conditions wood chip refining for production of MDF panel

BELINI, Ugo Leandro; TOMAZELLO FILHO, Mario; CHAGAS, Matheus Perez; OLIVEIRA, José Tarcísio da Silva
Fonte: Sociedade de Investigações Florestais Publicador: Sociedade de Investigações Florestais
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.64%
A utilização da madeira de eucalipto na confecção de painéis MDF é recente, tornando-se necessário entender as modificações em sua estrutura anatômica durante as etapas do processo industrial, notadamente no desfibramento dos cavacos. Com esse objetivo, neste estudo foram aplicadas três condições diferenciadas de desfibramento dos cavacos, alterando-se (i) o tempo de aquecimento, (ii) as pressões de digestão e de desfibramento e (iii) a energia específica de desfibramento, sendo avaliadas as características anatômicas dos componentes celulares da madeira. O aumento da intensidade de refino dos cavacos de madeira reduziu o comprimento médio das fibras e aumentou o porcentual de fibras quebradas, corroborando as imagens de microscopia eletrônica de varredura, além da diminuição do número dos vasos e de células de parênquima. Essa condição de desfibramento mais intensa promoveu, também, um característico escurecimento da coloração da polpa composta pelos elementos celulares da madeira. A aplicação de variáveis de desfibramento mais brandas aumentou a presença de feixes de fibras e do número de vasos e de parênquima, resultando em uma polpa de coloração mais clara. As alterações das características morfológicas dos componentes celulares da madeira dos cavacos de eucalipto...

Caracterização da estrutura anatômica, densidade básica e morfologia de cavacos da madeira de Eucalyptus grandis para a produção de painéis MDF; Characterization of wood anatomy, basic density, and morphology of Eucalyptus grandis chips for MDF production

BELINI, Ugo Leandro; TOMAZELLO FILHO, Mario; CHAGAS, Matheus Perez; DIAS, Carlos Tadeu dos Santos
Fonte: Sociedade de Investigações Florestais Publicador: Sociedade de Investigações Florestais
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.91%
O aumento na produção dos painéis Medium Density Fiberboard (MDF) confeccionados com madeira de espécies de Eucalyptus spp de rápido crescimento evidencia a necessidade da caracterização dos seus componentes celulares, da densidade básica e da morfologia de cavacos. Com esse objetivo, foram coletadas três amostras de cavacos de madeira de árvores de Eucalyptus grandis, na linha de produção de indústria de painel. Em laboratório, os cavacos foram dissociados por maceração, para a avaliação das dimensões das fibras e dos vasos; determinou-se a densidade básica dos cavacos, bem como se caracterizaram a sua espessura e morfologia. Os resultados indicaram valores médios de 1005-19,7-11,8-3,9 µm para o comprimento, largura, diâmetro do lume e espessura média da parede das fibras, respectivamente. A densidade básica da madeira foi de 0,432 g/cm³ e a espessura dos cavacos, de 4,36 mm. Os valores médios de retenção dos cavacos foram de 0,9-16,9-44,5-30,7-6,1-0,9% nas peneiras 40, 25, 16, 8, 3,35 mm e fundo, respectivamente, sendo 75,2% retidos nas peneiras de 16-8 mm de abertura. Os resultados das análises anatômicas e morfológicas dos cavacos de madeira foram discutidos e comparados com informações da literatura especializada e correlacionados com o processo produtivo de chapas MDF.; The increase of the MDF panels (Medium Density Fiberboard) production by the use of the fast growing eucalypt wood species it evidences the need of the characterization of the cellular components...

Technological advances and mechanistic basis for fungal biopulping

FERRAZ, Andre; GUERRA, Anderson; MENDONCA, Regis; MASARIN, Fernando; VICENTIM, Marcos P.; AGUIAR, Andre; PAVAN, Paulo C.
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.69%
Biopulping fundamentals, technology and mechanisms are reviewed in this article. Mill evaluation of Eucalyptus grandis wood chips biotreated by Ceriporiopsis subvermispora on a 50-tonne pilot-plant demonstrated that equivalent energy savings can be obtained in lab- and mill-scale biopulping. Some drawbacks concerning limited improvements in pulp strength and contamination of the chip pile with opportunist fungi have been observed. The use of pre-cultured wood chips as inoculum seed for the biotreatment process minimized contamination problems related to the use of blended mycelium and corn-steep liquor in the inoculation step. Alkaline wash restored part of the brightness in biopulps and marketable brightness values were obtained by one-stage bleaching with 5% H2O2 when bio-TMP pulps were under evaluation. Considering the current scenario, the understanding of biopulping mechanisms has gained renewed attention because more resistant and competitive fungal species could be selected with basis on a function-directed screening project. A series of studies aimed to elucidate structural changes in lignin during wood biodegradation by C. subvermispora had indicated that lignin depolymerization occurs during initial stages of wood biotreatment. Aromatic hydroxyls did not increase with the split of aryl-ether linkages...

Evaluation of Eucalyptus grandis Hill ex Maiden biopulping with Ceriporiopsis subvermispora under non-aseptic conditions

MASARIN, Fernando; FERRAZ, Andre
Fonte: WALTER DE GRUYTER & CO Publicador: WALTER DE GRUYTER & CO
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.91%
In biopulping, efficient wood colonization by a selected white-rot fungus depends on previous wood chip decontamination to avoid the growth of primary molds. Although simple to perform in the laboratory, in large-scale biopulping trials, complete wood decontamination is difficult to achieve. Furthermore, the use of fungal growth promoters such as corn steep liquor enhances the risk of culture contamination. This paper evaluates the ability of the biopulping fungus Ceriporiopsis subvermispora to compete with indigenous fungi in cultures of fresh or poorly decontaminated Eucalyptus grandis wood chips. While cultures containing autoclaved wood chips were completely free of contaminants, primary molds grew rapidly when non-autoclaved wood chips were used, resulting in heavily contaminated cultures, regardless of the C. subvermispora inoculum/wood ratio evaluated (5, 50 and 3000 mg mycelium kg(-1) wood). Studies on benomyl-amended medium suggested that the fungi involved competed by consumption of the easily available nutrient sources, with C. subvermispora less successful than the contaminant fungi. The use of acid-washed wood chips decreased the level of such contaminant fungi, but production of manganese peroxidase and xylanases was also decreased under these conditions. Nevertheless...

Alkaline-sulfite chemithermomechanical pulping of Eucalyptus grandis biotreated by Ceriporiopsis subvermispora under varied culture conditions

VICENTIM, Marcos Paulo; FERRAZ, Andre
Fonte: WALTER DE GRUYTER & CO Publicador: WALTER DE GRUYTER & CO
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.83%
The effect of different culture conditions have been evaluated concerning the extracellular enzyme activities of the white-rot fungus Ceriporiopsis subvermispora growing on Eucalyptus grandis wood. The consequence of the varied fungal pretreatment on a subsequent chemithermomechanical pulping (CTMP) was addressed. In all cultures, manganese peroxidase (MnP) and xylanase were the predominant extracellular enzymes. The biopulping efficiency was evaluated based on the amount of fiber bundles obtained after the first fiberizing step and the fibrillation levels of refined pulps. It was found that the MnP levels in the cultures correlated positively with the biopulping benefits. On the other hand, xylanase and total oxalate levels did not vary significantly. Accordingly, it was not possible to determine whether MnP accomplishes the effect alone or depends on synergic action of other extracellular agents. Pulp strength and fiber size distribution were also evaluated. The average fiber length of CTMP pulps prepared from untreated wood chips was 623 mu m. Analogous values were observed for most of the biopulps; however, significant amounts of shorter fibers were found in the biopulp prepared from wood chips biotreated in cultures supplemented with glucose plus corn-steep liquor. Despite evidence of reduced average fiber length...

Caracterização e alterações na estrutura anatômica da madeira do Eucalyptus grandis em três condições de desfibramento e efeito nas propriedades tecnológicas de painéis MDF; Characterization and anatomical structure alterations of Eucalyptus grandis wood in three refining conditions and effect in technological properties of MDF panels

Belini, Ugo Leandro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 20/04/2007 PT
Relevância na Pesquisa
46.83%
Constata-se, atualmente, uma grande demanda de crescimento na produção de painéis MDF de madeira de eucalipto em relação à do pinus, comumente utilizada na indústria. Pelo exposto, o presente trabalho teve como objetivo caracterizar os componentes morfológicos da madeira de cavacos de Eucalyptus grandis, “in natura” e submetidas a três condições diferentes de desfibramento (tempo, pressão e energia), sendo denominadas de condição intermediária, de menor e de maior intensidade de refino (A, B e C, respectivamente). As características tecnológicas das chapas MDF obtidas para as três condições de desfibramento foram, da mesma forma, analisadas segundo a norma NBR 15316. No desenvolvimento do trabalho foram coletados para as três condições de desfibramento, em toda a cadeia produtiva do painel MDF: cavacos de madeira, material lenhoso desfibrado e painéis MDF final em escala industrial e laboratorial. Os cavacos de madeira foram caracterizados com respeito a sua estrutura microscópica; o material lenhoso desfibrado nas 3 condições foi avaliado através do seu fracionamento em peneiras seguindo-se a classificação morfológica e a caracterização microscópica dos componentes celulares de cada fração. Os resultados mostraram que os cavacos de madeira coletados no silo da unidade fabril apresentaram-se homogêneos nas 3 pré-condições avaliadas e não exerceram qualquer influência nos tratamentos. A condição de desfibramento mais branda induziu a formação de feixes de fibra e manutenção de vasos e parênquima com as fibras apresentando maior comprimento médio. A condição de desfibramento mais drástica induziu o rompimento da parede das fibras...

Biopolpação a partir de cultivos mistos de basidiomicetos sobre madeira de Eucalyptus grandis e Eucalyptus urograndis; Biopulping based on mixed cultures of basidiomycetes on Eucalyptus grandis and Eucalyptus urograndis (E. grandis x E. urophilla hybrids) wood chips

Cunha, Gina Gabriela Seabra
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/12/2011 PT
Relevância na Pesquisa
46.8%
A biopolpação consiste no biotratamento de madeira por fungos degradadores de lignina como etapa prévia à produção de polpa celulósica. De uma forma geral, as madeiras biotratadas facilitam os processos posteriores de polpação. Entretanto, ensaios anteriores que avaliaram a biopolpação em escala piloto mostraram que é difícil estabelecer os cultivos de basidiomicetos de interesse livre de bolores contaminantes, já que não é fácil controlar perfeitamente a assepsia durante a inoculação. Para contribuir com o avanço do processo de biopolpação, este trabalho avaliou os cultivos mistos de Ceriporiopsis subvermispora e Phanerochaete chrysosporium sobre madeira de Eucalyptus grandis e Eucalyptus urograndis em regimes de incubação em temperaturas variáveis e em condições não assépticas. A estratégia de iniciar os cultivos em temperatura mais elevada (37°C) e depois manter as culturas em temperaturas variáveis de 27°C e 37°C se mostrou eficiente para inibir o crescimento de contaminantes indesejáveis tanto nos cultivos mistos como nos individuais de cada espécie avaliada. Para avaliar o efeito do biotratamento da madeira numa etapa subsequente de polpação quimiotermomecânica (CTMP) foi feito um estudo preliminar de ajuste de variáveis de polpação por refinamento mecânico de cavacos pré-digeridos com licor alcalino contendo sulfito de sódio. Os dados mostraram que é possível simular o rendimento e as características fisico-mecânicas de polpas industriais empregando uma etapa de pré-digestão dos cavacos com 6% de Na2SO3 e 3% de NaOH a 120°C por 2 h...

Biodegradação de madeira por Ceriporiopsis subvermispora: caracterização dos polímeros residuais; Biodegradation of the wood Ceriporiopsis subvermispora: characterization of residual polymers

Guerra, Anderson de Almeida
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/05/2002 PT
Relevância na Pesquisa
46.75%
A Biopolpação é definida como o pré-tratamento de cavacos de madeira, designado como um processo de fermentação em estado sólido, para a produção de polpas mecânicas e químicas. Apesar dos resultados promissores obtidos pelo pré-tratamento com fungos seguido de reações de polpação, não há correlação entre o padrão de biodegradação dos componentes da madeira e o aumento na eficiência dos métodos de polpação subseqüentemente utilizados. Esta falta de correlação sugere que os benefícios do biotratamento dependem mais do tipo de modificação induzida na madeira do que da extensão da mineralização de seus componentes. Dentro deste contexto, este estudo visa o entendimento dos mecanismos químicos e bioquímicos, que poderiam explicar as alterações estruturais ocorridas nos componentes principais da madeira durante a etapa de biopolpação. Pinus taeda foi degradado por Ceriporiopsis subvermispora por períodos de 15 a 90 dias em condições de fermentação sólida. O fungo degradou lignina e extrativos extensivamente, sem remover grandes quantidades de glucana. As polioses foram significativamente removidas após 60 dias de degradação (7%), chegando a 31 % após 90 dias. A lignina e os polissacarídeos residuais ...

Aumento da eficiência do processo kraft de polpação a partir de pré-tratamento de cavacos de madeira de eucalipto; Increase of the kraft pulping process efficiency from pretreatment of eucalyptus wood chips

Vivian, Magnos Alan
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/02/2015 PT
Relevância na Pesquisa
47.02%
O presente estudo teve por objetivo avaliar a eficiência da extração de lignina de cavacos da madeira de Eucalyptus grandis x Eucalyptus urophylla a partir de pré-tratamentos com xilenosulfonato de sódio (SXS), bem como determinar as condições ótimas destes, com intuito de aumentar a eficiência dos processos de polpação e branqueamento, através da redução da necessidade de reagentes. Primeiramente procedeu-se a caracterização física, química e morfológica da madeira. Na sequência os cavacos foram submetidos à pré-tratamentos a partir da combinação dos fatores: tempo (1, 3, 6, 9 e 12 h), concentração de SXS (0, 10, 20 e 30 %) e temperatura (110, 120 e 130 ºC). Após os pré-tratamentos determinaram-se os parâmetros de rendimento e teor de lignina remanescente nos cavacos, a partir dos quais obtiveram-se os pontos ótimos referentes a cada fator, para o máximo rendimento e extração de lignina. De posse dos pontos ótimos para cada parâmetro, esses foram replicados para obtenção de cavacos pré-tratados que foram utilizados nas curvas de cozimento pelo processo kraft de polpação com e sem a aplicação de antraquinona e comparados a cavacos normais. A partir das curvas de cozimento determinou-se a carga alcalina necessária para obtenção de polpa com número kappa 15 ± 0...

Phenolic Acids, Phenolic Aldehydes and Furanic Derivatives in Oak Chips: American vs. French Oaks

Cabrita, M.J.; Barrocas Dias, C.; Costa Freitas, A.M.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.75%
Phenolic acids (gallic, vanillic, syringic and ellagic acids), phenolic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde) and furanic derivatives (furfural, 5-methylfurfural and 5-hydroxymethylfurfural) were quantified in commercial American and French oak chips. Chips with different sizes and toast degrees were used. Compounds were extracted directly from the wood samples in order to determine possible differences among woods as well as toast degree. Likewise, the compounds were extracted from a synthetic wine solution to which the chip woods had been added. The results show that French wood chips are generally richer than the American ones. The total amount of phenolic compounds increases with toasting level, with the non-toasted chips being the poorest ones. The degree of extraction from the synthetic wine solution seems to be related to the shape of the chips, rather than to the wood type or toast degree.

Volatile compounds from oak, cherry, chestnut and acacia chips: influence of toasting level

Martins, Nuno; Garcia, Raquel; Gomes da Silva, Marco; Cabrita, Maria Joao
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.7%
In the present study, the volatile composition of wood chips from several botanical species potentially relevant for oenological purposes, namely acacia (unknown specie), chestnut (Castanea sativa), cherry (Prunus cerasus) and oak (Quercus robur) was studied by GC/MS. In order to evaluate the effect of the toasting process on volatile compounds contents we have extended our study to wood chips from the botanical species described above, subjected to different toasting levels, such as untoasted and medium toast. To achieve this goal, a preliminary step comprising the extraction of the volatile compounds by pressurized liquid extraction (PLE) has been performed followed by the analysis and identifi cation of those compounds by GC/MS. The identifi cation was tentatively achieved attending to the characteristic fragmentation patterns of these compounds and by comparison with those reported in the literature. The determination of linear retention indexes has allowed the confi rmation of those attributions. Within this study, we were able to identify 45 compounds, arising from polysaccharides, lipids, lignin and polyphenols degradation. Additionally, 16 other compounds were identifi ed in the different wood species under study although their origin is not fully known. In general...

Phenolic and furanic compounds of Portuguese chestnut and French, American and Portuguese oak wood chips

Garcia, Raquel; Soares, Bruno; Barrocas Dias, Cristina; Ana Maria, Costa Freitas; Cabrita, Maria Joao
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.7%
Botanical species used on aging process must be wisely and judiciously chosen, and for this selection, a basic knowledge of the chemical composition of woods is warranted. Aiming to contribute to extend the knowledge of the chemical composition of several wood species useful for enological purposes, we have focused our studies on Portuguese chestnut and French, American and Portuguese oak chips. The profile of low molecular weight phenolic composition of these chips was achieved, using an optimized extraction method based on pressurized liquid extraction, followed by the quantification of phenolic acids, phenolic aldehydes and furanic derivatives by high-performance liquid chromatography (HPLC-DAD). The identification of those compounds was also confirmed by LC-DAD/ESI-MS. This study allowed the determination of the low molecular phenolic composition of Portuguese chestnut and French, American and Portuguese oak wood. According to our results, the influence of the botanical species seems to be more relevant than the geographic origin of the wood species.

Combining hens for egg production and trees for wood chips in an agroforestry system: lessons learnt after 3 years

Spangenberg, G.; Hein, S.; Schneider, J.
Fonte: EURAF Publicador: EURAF
Tipo: Outros
Publicado em /06/2014 ENG
Relevância na Pesquisa
56.52%
A 7.1 ha agroforestry field experiment located in south-western Germany demonstrates, how to combine short rotation coppicing for fuel wood production with poultry keeping with the production of eggs. This combined system offers additional ecosystem services and gives multifarious benefits. The agroforestry system has been established since 2009 by an organic farmer (certified) in close cooperation with the University of Applied Forest Sciences Rottenburg. While changing from indoor to outdoor housing required by the standards of organic farming the owner of the farmland wanted to meet not only with the standards, but additionally he wanted to fulfill objectives like: * Raising and keeping hens in a close-to–nature environment, * Finding a way, that hens exploit all the terrain available and not only those areas close to the chicken-coop, * Improving the conditions of the vegetation, soil and hygiene of the hens. The agroforestry system has been implemented based on two components: The first component consists of the construction of mobile chicken-coops (patent of the farmer). The mobile coops can be moved in their position over the experimental plots several times per year without much effort. The second component consists of strips of willows and poplars...

Biological degradation of resin acids in wood chips by wood-inhabiting fungi.

Wang, Z; Chen, T; Gao, Y; Breuil, C; Hiratsuka, Y
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1995 EN
Relevância na Pesquisa
46.7%
Resin acids in many pulp mill effluents are primary sources of toxicity to fish. Inconsistent biological detoxification of chlorinated and nonchlorinated resin acids in secondary treatment of pulp mill effluents is a continuing source of concern. An alternative approach to effluent detoxification is to remove or modify the toxic compounds present in wood chips prior to pulping. Results from experiments in which lodgepole pine sapwood chips were inoculated with several fungal candidates indicate that the total resin acid content can be reduced by up to 67% after fungal growth. Such a treatment could be an efficient and environmentally acceptable way for deresinating wood chips and so decreasing the toxicity of pulp mill effluents.

Delignification of Wood Chips and Pulps by Using Natural and Synthetic Porphyrins: Models of Fungal Decay †

Paszczyński, Andrzej; Crawford, Ronald L.; Blanchette, Robert A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1988 EN
Relevância na Pesquisa
46.75%
Kraft pulps, prepared from softwoods, and small chips of birch wood were treated with heme and tert-butyl hydroperoxide in aqueous solutions at reflux temperature. Analyses of treated pulps showed decreases in kappa number (a measure of lignin content) from about 36 to less than 2, with concomitant increases in brightness (80% increase in the better samples). Analyses of treated wood chips revealed selective delignification and removal of hemicelluloses. After 48 h of treatment, lignin losses from the wood chips approached 40%, and xylose/mannose (hemicellulose) losses approached 70%, while glucose (cellulose) losses were less than 10%. Examination of delignified chips by transmission electron microscopy showed that the removal of lignin occurred in a manner virtually indistinguishable from that seen after decay by white rot fungi. Various metalloporphyrins, which act as biomimetic catalysts, were compared to horseradish peroxidase and fungal manganese peroxidase in their abilities to oxidize syringaldazine in an organic solvent, dioxane. The metalloporphyrins and peroxidases behaved similarly, and it appeared that the activities of the peroxidases resulted from the extraction of heme into the organic phase, rather than from the activities of the enzymes themselves. We concluded that heme-tert-butyl hydroperoxide systems in the absence of a protein carrier mimic the decay of lignified tissues by white rot fungi.

Choice by rats for enriched versus standard home cages: Plastic pipes, wood platforms, wood chips, and paper towels as enrichment items

Bradshaw, A. Lynn; Poling, Alan
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1991 EN
Relevância na Pesquisa
46.69%
The purpose of the present study was to determine whether simple additions to the home cages of rats made those cages preferable to standard housing arrangements. Results indicated that most rats preferred cages with wood platforms, wood chips, and paper towels to otherwise identical cages without these items. Wood chips were not, however, practical with the cages used in the present study. Plastic pipes caused no problems but were not preferred by most animals. Both wood platforms and paper towels created no problems and appeared to be useful as enrichment items. The latter were preferred to the former in a direct comparison.

Development of Bursaphelenchus xylophilus Populations in Wood Chips with Different Moisture Contents

Halik, S.; Bergdahl, D. R.
Fonte: Society of Nematologists Publicador: Society of Nematologists
Tipo: Artigo de Revista Científica
Publicado em /01/1990 EN
Relevância na Pesquisa
46.84%
Bags of Pinus strobus wood chips with moisture contents of 38, 92, 164, and 217% (oven dry weight) were inoculated with Bursaphelenchus xylophilus and incubated at 30 C in order to determine the effect of wood moisture on nematode population development. Nematodes were extracted after 2, 4, 8, and 12 weeks. Population levels were greatest in wood chips with a moisture content of 38% and decreased successively with each higher moisture content. In chips with the three lower moisture contents, populations peaked at 2 weeks, but at 217% moisture, they peaked at 8 weeks. By 12 weeks, nematode populations had declined in wood chips with 92 and 164% moisture contents. The fungi most frequently isolated from the wood chips were Alternaria, Fusarium, Gliocladium, Graphium, Penicillium, Trichoderma, and Mucorales.

Oxygen Depletion and Formation of Toxic Gases following Sea Transportation of Logs and Wood Chips

Svedberg, Urban; Petrini, Caroline; Johanson, Gunnar
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.81%
Several recent accidents with fatal outcomes occurring during discharge of logs and wood chips from ships in Swedish ports indicate the need to better understand the atmospheric conditions in holds and connecting stairways. The principal aim of the present study was to assess the air levels of oxygen and toxic gases in confined spaces following sea transportation of logs and wood chips. The focus of the study was the conditions in the stairways, as this was the location of the reported accidents. Forty-one shipments of logs (pulpwood) and wood chips carried by 10 different ships were investigated before discharge in ports in northern Sweden. A full year was covered to accommodate variations due to seasonal temperature changes. The time from completion of loading to discharge was estimated to be 37–66 h (mean 46 h). Air samples were collected in the undisturbed air of altogether 76 stairways before the hatch covers were removed. The oxygen level was measured on-site by handheld direct-reading multi-gas monitors. On 16 of the shipments, air samples were additionally collected in Tedlar® bags for later analysis for carbon dioxide, carbon monoxide, and hydrocarbons by fourier transform infrared spectroscopy. The mean oxygen level was 10% (n = 76) but in 17% of the samples the oxygen level was 0%. The oxygen depletion was less pronounced during the cold season. The mean CO2 and CO levels were 7.5% (n = 26) and 46 p.p.m. (n = 28)...

Examination of the potential for reuse of chromated copper arsenate wood waste by nitric acid pulping.

Wood, Connell
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
56.44%
Treated timber is a widely used construction material, as it is resistant to insect and fungal attack. The most commonly used timber treatment solution worldwide is copper chromium arsenate (CCA) pressure treated wood (APVMA 2005a). Environmental and health issues have been raised over CCA wood, with major particular concern raised on the possibilities of arsenic in the wood potentially leaching out. The Australian Pesticides and Veterinary Medicines Authority (APVMA) have limited its usage to minimise human contact with CCA structures (APVMA 2005a). In South Australia, CCA applications increased dramatically with the expansion of the winery industry where CCA treated timber posts were widely used for vineyard trellises. Due to the mechanical method by which most grapes are harvested, roughly 2% of all posts are broken and require disposal annually (SAEPA 2008). The Environmental Protection Agency of South Australia (EPASA) have placed restrictions on CCA disposal from vineyards (SAEPA 2004) and waste CCA stock is either stockpiled or sent to specially lined landfills incurring an estimated cost penalty of over $AU 200 per tonne¹ . Clearly, improved CCA treatment technologies must be developed to reduce (or eliminate) the cost of CCA disposal and to the footprint of land filled waste. CCA timber disposal techniques currently being researched are focussed primarily on thermal and biological routes. Thermal techniques are problematic due to volatilization of the arsenic in the product...

Volatile compounds from oak, cherry, chestnut and acacia chips: influence of toasting level

Martins,Nuno; Garcia,Raquel; Silva,Marco Gomes da; Cabrita,Maria João
Fonte: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional) Publicador: INIAV - DOIS PORTOS (Ex-Estação Vitivinícola Nacional)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
56.7%
In the present study, the volatile composition of wood chips from several botanical species potentially relevant for oenological purposes, namely acacia (unknown specie), chestnut (Castanea sativa), cherry (Prunus cerasus) and oak (Quercus robur) was studied by GC/MS. In order to evaluate the effect of the toasting process on volatile compounds contents we have extended our study to wood chips from the botanical species described above, subjected to different toasting levels, such as untoasted and medium toast. To achieve this goal, a preliminary step comprising the extraction of the volatile compounds by pressurized liquid extraction (PLE) has been performed followed by the analysis and identi?cation of those compounds by GC/MS. The identi?cation was tentatively achieved attending to the characteristic fragmentation patterns of these compounds and by comparison with those reported in the literature. The determination of linear retention indexes has allowed the con?rmation of those attributions. Within this study, we were able to identify 45 compounds, arising from polysaccharides, lipids, lignin and polyphenols degradation. Additionally, 16 other compounds were identi?ed in the different wood species under study although their origin is not fully known. In general...