Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue ...Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. <i><span>Musa paradisiaca pseudostem</span></i><span>, </span><i><span>Theobroma cacao </span></i><span>stem and pod, and sawdust of </span><i><span>Ceiba pentandra</span></i><span> were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to </span><i><span>Coriolopsis polyzona</span></i><span> in accordance with ASTM D 2017</span><span>-</span><span>05. The results indicate that the weight loss for </span><i><span>Musa paradisiaca pseudostem</span></i><span> particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.</span>展开更多
An endophytic fungus producing 1,8-cineole from Neolitsea pulchella (Meissn.) Merr. was identified as Annulohypoxylon sp. by phylogenetic analyses of the sequence alignments of ITS rDNA, β-tubulin, Actin and EF1-α. ...An endophytic fungus producing 1,8-cineole from Neolitsea pulchella (Meissn.) Merr. was identified as Annulohypoxylon sp. by phylogenetic analyses of the sequence alignments of ITS rDNA, β-tubulin, Actin and EF1-α. This isolate produces an attractive spectrum of volatile organic compounds (VOCs) with only one dominant component, 1,8-cineole, as identified by gas chromatography-mass spectrometry (GC-MS). The fungus was able to grow in seven media with different carbon sources, and five raw agro-forest residues. The content of 1,8-cineole in the mixed VOCs via fungus reached up to 94.95% and 91.25% relative area in PDA and raw poplar sawdust, respectively. Under optimum test conditions, the fungus produced 1,8-cineole at the 0.764 ppmv in 50 mL head spaces in PDA. Interestingly, 1,8-cineole is an ideal fuel additive for both diesel and gasoline engines. Also, this is the first isolate, in this group of fungi, making cineole, which produces as its primary VOC product which makes it an ideal organism for strain improvement. Such as step will be critical for its ultimate use in biofuel production.展开更多
This study investigated the possible use of four agro-forest residues generated in Ghana as an alternative raw material for particleboard manufacture using cassava starch and urea formaldehyde as adhesives. The partic...This study investigated the possible use of four agro-forest residues generated in Ghana as an alternative raw material for particleboard manufacture using cassava starch and urea formaldehyde as adhesives. The particle size of the materials ranged from 0.5 mm to 1.5 mm. An industrial pressing machine was used to press the homogeneous single layer particleboard. Physical and mechanical properties were determined in accordance with ASTM D 1037-06a and ASTM D 7519-11. The results indicate that the density of the particleboards produced ranged from 421 kg/m<sup>3</sup> to 598 kg/m<sup>3</sup>. The water absorption property of the particleboards also ranged from 7.66% to 22.41% and 18.17% to 59.46% for 2-hour and 24-hour immersions respectively. Additionally, the thickness swelling of the particleboards ranged from 3.38% to 5.03% and 9.37% to 21.49% for 2-hour, and 24-hour immersions respectively. The results further indicate that the modulus of elasticity, modulus of rapture, internal bond strength and hardness of the particleboards produced for both cassava starch and urea formaldehyde were adequate. Comparatively, for all the agro-forest materials used for this study, the physical and mechanical properties of the particleboards produced using urea formaldehyde as adhesive was better than those produced using cassava starch as adhesive. It could be concluded that the particleboards produced could be used for indoor applications or interior furnishings, under dry conditions. Additionally, it is recommended that further studies that combine cassava starch and urea formaldehyde as adhesives be conducted, as well as studies on combining <em>Plantain pseudostem</em> and Cacao pod in particleboard production.展开更多
文摘Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. <i><span>Musa paradisiaca pseudostem</span></i><span>, </span><i><span>Theobroma cacao </span></i><span>stem and pod, and sawdust of </span><i><span>Ceiba pentandra</span></i><span> were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to </span><i><span>Coriolopsis polyzona</span></i><span> in accordance with ASTM D 2017</span><span>-</span><span>05. The results indicate that the weight loss for </span><i><span>Musa paradisiaca pseudostem</span></i><span> particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.</span>
文摘An endophytic fungus producing 1,8-cineole from Neolitsea pulchella (Meissn.) Merr. was identified as Annulohypoxylon sp. by phylogenetic analyses of the sequence alignments of ITS rDNA, β-tubulin, Actin and EF1-α. This isolate produces an attractive spectrum of volatile organic compounds (VOCs) with only one dominant component, 1,8-cineole, as identified by gas chromatography-mass spectrometry (GC-MS). The fungus was able to grow in seven media with different carbon sources, and five raw agro-forest residues. The content of 1,8-cineole in the mixed VOCs via fungus reached up to 94.95% and 91.25% relative area in PDA and raw poplar sawdust, respectively. Under optimum test conditions, the fungus produced 1,8-cineole at the 0.764 ppmv in 50 mL head spaces in PDA. Interestingly, 1,8-cineole is an ideal fuel additive for both diesel and gasoline engines. Also, this is the first isolate, in this group of fungi, making cineole, which produces as its primary VOC product which makes it an ideal organism for strain improvement. Such as step will be critical for its ultimate use in biofuel production.
文摘This study investigated the possible use of four agro-forest residues generated in Ghana as an alternative raw material for particleboard manufacture using cassava starch and urea formaldehyde as adhesives. The particle size of the materials ranged from 0.5 mm to 1.5 mm. An industrial pressing machine was used to press the homogeneous single layer particleboard. Physical and mechanical properties were determined in accordance with ASTM D 1037-06a and ASTM D 7519-11. The results indicate that the density of the particleboards produced ranged from 421 kg/m<sup>3</sup> to 598 kg/m<sup>3</sup>. The water absorption property of the particleboards also ranged from 7.66% to 22.41% and 18.17% to 59.46% for 2-hour and 24-hour immersions respectively. Additionally, the thickness swelling of the particleboards ranged from 3.38% to 5.03% and 9.37% to 21.49% for 2-hour, and 24-hour immersions respectively. The results further indicate that the modulus of elasticity, modulus of rapture, internal bond strength and hardness of the particleboards produced for both cassava starch and urea formaldehyde were adequate. Comparatively, for all the agro-forest materials used for this study, the physical and mechanical properties of the particleboards produced using urea formaldehyde as adhesive was better than those produced using cassava starch as adhesive. It could be concluded that the particleboards produced could be used for indoor applications or interior furnishings, under dry conditions. Additionally, it is recommended that further studies that combine cassava starch and urea formaldehyde as adhesives be conducted, as well as studies on combining <em>Plantain pseudostem</em> and Cacao pod in particleboard production.
