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Decay Resistance of Particleboards Manufactured with Four Agro-Forest Residues Using Cassava Starch and Urea Formaldehyde as Adhesives

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Journal of Agricultural Chemistry and Environment 2020年第4期9卷 240-254页

作者： Prosper mensah Stephen Jobson Mitchual Mary Mamle Apetorgbor kwasi frimpong-mensah CSIR-Forestry Research Institute of Ghana KNUST Kumasi Ghana Department of Construction and Wood Technology Education University of Education Winneba Kumasi Campus Kumasi Ghana Department of Wood Science and Technology Kwame Nkrumah University of Science and Technology Kumasi Ghana

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. Musa paradisiaca pseudostem, Theobroma cacao stem and pod, and sawdust of Ceiba pentandra 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 Coriolopsis polyzona in accordance with ASTM D 2017-05. The results indicate that the weight loss for Musa paradisiaca pseudostem 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.

关键词： Agro-Forest Residue Cassava Starch Decay Resistance Particleboard Urea Formaldehyde

Characterization of Particleboard Produced from Residues of <i>Plantain pseudostem</i>, Cacao Pod and Stem and <i>Ceiba</i>

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Materials Sciences and Applications 2020年第12期11卷 817-836页

作者： Stephen J. Mitchual Prosper mensah kwasi frimpong-mensah Emmanuel Appiah-Kubi Department of Construction and Wood Technology Education Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development Kumasi Ghana CSIR-Forestry Research Institute of Ghana KNUST Kumasi Ghana Department of Wood Science and Technology Kwame Nkrumah University of Science and Technology Kumasi Ghana

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/m3 to 598 kg/m3. 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 Plantain pseudostem and Cacao pod in particleboard production.

关键词： Agro-Forest Residue Cassava Starch Particleboard Physico-Mechanical Properties Urea Formaldehyde

Evaluation of Fuel Properties of Six Tropical Hardwood Timber Species for Briquettes

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Journal of Sustainable Bioenergy Systems 2014年第1期4卷 1-9页

作者： Stephen J. Mitchual kwasi frimpong-mensah Nicholas A. Darkwa Department of Construction and Wood Technology Education University of Education Winneba Kumasi Campus Kumasi Ghana Department of Wood Science and Technology Kwame Nkrumah University of Science and Technology Kumasi Ghana

The fuel potential of six tropical hardwood species namely: Triplochiton scleroxylon, Ceiba pentandra, Aningeria robusta, Terminalia superba, Celtis mildbreadii and Piptadenia africana were studied. Properties studied included species density, gross calorific value, volatile matter, ash content, organic carbon and elemental composition. Fuel properties were determined using standard laboratory methods. The result indicates that the gross calorific value (GCV) of the species ranged from 20.16 to 22.22 MJ/kg and they slightly varied from each other. Additionally, the GCV of the biomass materials were higher than that of other biomass materials like;wheat straw, rice straw, maize straw and sugar cane. The ash and volatile matter content varied from 0.6075 to 5.0407%, and 75.23% to 83.70% respectively. The overall rating of the properties of the six biomass materials suggested that Piptadenia africana has the best fuel property to be used as briquettes and Aningeria robusta the worse. This study therefore suggests that a holistic assessment of a biomass material needs to be done before selecting it for fuel purpose.

关键词： Ash Content Briquette Calorific Value Elemental Composition Species Volatile Matter

Relationship between Physico-Mechanical Properties, Compacting Pressure and Mixing Proportion of Briquettes Produced from Maize Cobs and Sawdust

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Journal of Sustainable Bioenergy Systems 2014年第1期4卷 50-60页

This study examined the relationship between selected physico-mechanical properties, compacting pressure and mixing proportion of briquettes produced from combination of maize cob particles and sawdust of low, medium and high density timber species. Particle sizes of maize cobs and sawdust used for the study were ≤1 mm. The two materials were combined at mixing percentages of 90:10, 70:30 and 50:50 (Sawdust:maize cobs). Briquettes were produced at room temperature (28°C) using compacting pressures 20, 30, 40 and 50 MPa. The results suggested that combining maize cob particles with sawdust of low, medium and high density wood species could significantly enhance the relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from agricultural biomass residue like maize cobs. The results further indicated that the physical and mechanical characteristics of briquettes produced from combinations of sawdust of low density species and maize cobs were exceptionally higher than that produced from combinations of maize cob particles, and medium density and high density timber species. The R2 values for the regression model between the independent variables (mixing percentage and compacting pressure) and relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from combinations of maize cob particles and sawdust of low density species (Ceiba pentandra) were 0.966, 0.932 and 0.710 respectively. This study provides a hope for briquetting maize cobs at room temperature using a low compacting pressure.

关键词： Briquette Compacting Pressure Maize Cobs Mixing Proportions Physico-Mechanical Properties Sawdust

How Marie Sklodowska-Curie Doctoral Networks Can Support European Refractory Ecosystem in Context of The European Green Deal

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China's Refractories 2024年第2期33卷 1-9页

作者： Marc HUGER Glyn DERRICK Mossaab MOUIYA Andrea SALERNO kwasi Addo BOATENG Hrikeshava RANGANATHAN Amit Kumar GOPE Institute of Research for Ceramics(IRCER-UMR CNRS 7315) University of LimogesLimoges 87000France

The movement of the Iron&Steelmaking(I&S)industry towards Net-Zero emissions and digitalized processes through disruptive,breakthrough technologies will be achieved through the use of Hydrogen.The biggest challenge for the refractory industry is to continue to meet the performance expectations while,at the same time,moving to a more sustainable production direction.The complexity and urgency of these technological changes,highlighted by the European Green Deal,requires ambitious,international,interdisciplinary and intersectoral projects,bringing together institutes from across the global value chain,to carry out cutting edge research.The European Union,through its flagship doctoral training program,MSCA,has,and continues to support research and development as well as the promotion of the refractory industry in Europe.An introduction to two MSCA projects and some of the results achieved are highlighted within this article.

关键词： FIRE network Horizon 2020 Horizon Europe Marie Sklodowska-Curie Actions Doctoral networks European Green Deal

以1-丁基-3-甲基咪唑氯盐为溶剂制备生物降解可控的再生纤维素/支链淀粉共混纤维(英文)

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Journal of Donghua University(English Edition) 2024年

作者： KUMIAlex kwasi 范瑞玲张玥陈烨张玉梅东华大学材料科学与工程学院纤维材料改性国家重点实验室

以纤维素/支链淀粉/1-丁基-3-甲基咪唑氯盐离子液体为原料，采用干喷湿纺技术制备了生物降解可控的再生纤维素/支链淀粉共混纤维。形态、结构和化学分析结果表明，经两阶段溶解过程，成功制得致密、均匀、无孔洞的共混纤维。该共混纤维... 详细信息

以纤维素/支链淀粉/1-丁基-3-甲基咪唑氯盐离子液体为原料，采用干喷湿纺技术制备了生物降解可控的再生纤维素/支链淀粉共混纤维。形态、结构和化学分析结果表明，经两阶段溶解过程，成功制得致密、均匀、无孔洞的共混纤维。该共混纤维能通过水或95%（体积分数）乙醇处理实现再生。然而，共混纤维中存在由于纤维素与支链淀粉相互作用引起的结晶重排现象，导致结晶度普遍降低。当共混纤维中支链淀粉的质量分数为10%时，共混纤维拉伸强度高于纯纤维素纤维，而后随着支链淀粉质量分数增加，共混纤维拉伸强度下降。乙醇处理可减少共混纤维的亲水性，并提高共混纤维的结晶度。此外，共混纤维的降解速率与其所含支链淀粉质量分数成正比关系。尽管具有较高结晶度，但经乙醇处理的共混纤维比经水处理的具有更快的降解速率。这说明了支链淀粉和乙醇在调节降解过程中发挥了作用。

关键词：纤维素/支链淀粉共混纤维纤维素支链淀粉 1-丁基-3-甲基咪唑氯盐乙醇

Understanding the relationship between High Reliability Theory (HRT) ofmindful organizing and Safety Management Systems (SMS) within theaerospace industry: A cross-sectional quantitative assessment

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Journal of Safety Science and Resilience 2022年第2期3卷 105-114页

作者： Brian Eugene Teske Daniel kwasi Adjekum Department of Space Studies John D.Odegard School of Aerospace SciencesUniversity of North Dakota4149 University AvenueStop 9008Grand ForksND 58202-9008USA Department of Aviation John D.Odegard School of Aerospace SciencesUniversity of North Dakota.4149 University AvenueStop 9036Grand ForksND 58202-9008USA

There seems to be a paucity in extant literature that assesses the relationship between Safety Management Systems (SMS) and High Reliability Theory (HRT) behavior process of mindful organizing (MO) among aerospaceorganizations. There could be benefits for organizational safety by exploring this relationship in high-reliabilityorganizations (HROs) like the aerospace industry. Using a modified Safety Organizing Scale (SOS) by Vogus andSutcliffe (2007) and a validated SMS scale, the relationship between SMS and MO was measured. The perceptionsof a cross-section of respondents from commercial airlines with SMS and commercial space licensees without SMSin the United States (U.S.) was assessed. A four-factor model of MO had acceptable fit. A model showing the relationship between SMS and MO had good fit and showed a high significant strength of relationship (r = 0.82,p = 0.000) with a big effect size. There were also significant differences in mean responses among managementpersonnel and non-management personnel on the MO factor “sensitivity to operations” and the result suggestsmanagers were better at identifying personnel with skills and knowledge to ensure safer task accomplishmentthan non-management personnel. The study results suggest that the SMS requirements for commercial airlines inthe U.S. can enrich the identification and understanding of MO factors and it may be beneficial for the commercial space industry to formally adopt SMS. Future research studies may include direct comparisons in multipleaerospace organizations using a larger sample size to determine the overall understanding of MO factors and howit affects SMS.

关键词： Mindful organizing Safety Management Systems High-reliability organization Aerospace Commercial airlines Commercial space licensees Organization safety

Effects of selective logging on tree diversity and some soil characteristics in a tropical forest in southwest Ghana

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Journal of Forestry Research 2014年第1期25卷 171-176页

作者： Alex Asase Bismark K.Asiatokor kwasi Ofori-frimpong Department of Botany University of Ghana Environmental Science Programme University of Ghana Cocoa Research Institute of Ghana (CRIG)

We investigated the effects of selective logging disturbances on tree diversity and soil characteristics in the Bia Conservation Area in southwest Ghana. The study was conducted in unlogged, 29-35 years post-logged and swamp forests using ten 25 m× 25 m plots. In total, we identified 310 individual trees belonging to 87 species. Mean Shannon-Weiner index was highest in the post-logged forest but there were no significant differences in tree density, dominance, or DBH size class distributions between these forests. Soil physical properties such as pH and bulk density up to 30 cm depth were similar in the two of forests In terms of soil nutrient status, available P, exchangeable K and total N contents were all similar in the unlogged and post-logged forests. Our findings suggest that the effects of logging on tree diversity are compara-tively long-term, in contrast to its short-term effects on some top soil physical and chemical characteristics.

关键词： tropical forest deforestation plant diversity soil propertiesGhana

Empirical studies of escape behavior find mixed support for the race for life model

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Current Zoology 2022年第3期68卷 305-313页

作者： kwasi WRENSFORD Jahaziel GUTIERREZ William E.COOPERJR Daniel T.BLUMSTEIN Department of Integrative Biology Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCA 94720USA The Rocky Mountain Biological Laboratory Crested ButteCO 81224USA Department of Biology Indiana University Purdue University Fort WayneFort WayneIN 46805USA Department of Ecology and Evolutionary Biology University of California6121 Young Drive SouthLos AngelesCA 90095-1606USA

Escape theory has been exceptionally successful in conceptualizing and accurately predicting effects of numerous factors that affect predation risk and explaining variation in flight initiation distance(FID;predator–prey distance when escape begins).Less explored is the relative orientation of an approaching predator,prey,and its eventual refuge.The relationship between an approaching threat and its refuge can be expressed as an angle we call the“interpath angle”or“Φ,”which describes the angle between the paths of predator and prey to the prey’s refuge and thus expresses the degree to which prey must run toward an approaching predator.In general,we might expect that prey would escape at greater distances if they must flee toward a predator to reach its burrow.The“race for life”model makes formal predictions about howΦshould affect FID.We evaluated the model by studying escape decisions in yellow-bellied marmots Marmota flaviventer,a species which flees to burrows.We found support for some of the model’s predictions,yet the relationship betweenΦand FID was less clear.Marmots may not assessΦin a continuous fashion;but we found that binning angle into 445°bins explained a similar amount of variation as models that analyzed angle continuously.Future studies ofΦ,especially those that focus on how different species perceive relative orientation,will likely enhance our understanding of its importance in flight decisions.

关键词： antipredator behavior escape behavior escape theory escape trajectory race for life model