Effect of intermittent heat treatment on crystallinity in wood cellulose     

Md. Tariqur Rabbani Bhuiyan  Nobuyuki Hirai  Nobuo Sobue 《Journal of Wood Science》2001,47(5):336-341

The effect of intermittent heat treatment on cellulose crystallites in wood was studied to evaluate quantitatively the changes of crystallinity induced by intermittent and continuous heating. The changes in crystallinity were found to be strongly affected by the intermittent heat treatment. The increased crystallinity, the width of the crystals, and the piezoelectric properties were the same for the first intermittent heating as for continuous heating. Further intermittent heating for the same time duration and temperature had no effect on the above properties, probably due to the stopping of the thermal reaction during the interval. Our results suggested that intermittent heat treatment has certain critical cooling temperatures that stop the thermal reaction and are closely related to the duration of the interval. Samples once exposed to a certain duration of heat treatment and then cooled need more time, about twice that of the first duration of intermittent heating compared with continuous heating, to reach maximum crystallinity in wood cellulose.  相似文献   

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin II: effects of processing parameters   总被引：1，自引：0，他引：1  

Md Iftekhar?ShamsEmail author  Hiroyuki?Yano 《Journal of Wood Science》2004,50(4):343-350

To obtain high-strength phenol formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, the effects of resin content, preheating temperature, pressing temperature, and pressing speed on the compressive deformation of oven-dried low molecular weight PF resin-impregnated wood was investigated. With an increase of PF resin content, the Youngs modulus of the cell wall perpendicular to the fiber direction decreases, and collapse-initiating pressure decreases linearly with the Youngs modulus. This indicates that the occurrence of cell wall collapse is strain-dependent. By increasing preheating temperatures, the collapse-initiating pressure increases due to the increment of the Youngs modulus of the cell wall. An increase in pressing temperature results in the thermal softening of the cell wall and causes collapse at a lower pressure. The wood is compressed effectively despite accelerated resin curing. The pressing speed significantly affects the viscoelastic deformation of the cell wall and the wood is well deformed with decreasing pressing speed, although the differences in density and mechanical properties are relatively small after a pressure-holding period of 30min. In all the parameters examined in this study, the Youngs modulus and bending strength increase with increasing density.  相似文献   

Insecticidal and anti-microbial activity of bio-oil derived from fast pyrolysis of lignin,cellulose, and hemicellulose     

Hossain  Mohammad M.  Scott  Ian M.  McGarvey  Brian D.  Conn  Kenneth  Ferrante  Lorenzo  Berruti  Franco  Briens  Cedric 《Journal of pest science》2015,88(1):171-179

Journal of Pest Science - Conflicting views regarding synthetic pesticides include the successful use as pest management tools for agriculture and forestry on one hand and the threats to components...  相似文献   

Intra-specific patterns of δ13C,growth and wood density variation at sites of contrasting precipitation with implications for modelling carbon sequestration of tropical tree species     

Halder  Nirmol Kumar  Chowdhury  Md. Qumruzzaman  Fuentes  David  Possell  Malcolm  Merchant  Andrew 《Agroforestry Systems》2021,95(8):1429-1443

Agroforestry Systems - Tropical agroforestry practices play a crucial role in mitigating global climate change by absorbing CO2 from the atmosphere through photosynthesis and storing carbon in...  相似文献   

CO2 elevation and soil warming reduce cold hardiness of jack pine under photoperiods of seed origin and latitudes of potential migration     

Newaz  Shah Md.  Dang  Qing-Lai  Man  Rongzhou 《New Forests》2021,52(5):777-790

New Forests - Climate change is predicted to cause northward migration of boreal tree species. However, the success of such a migration will be determined by trees’ ability to acclimate to...  相似文献   

Application of Biofloc Technology for the culture of Heteropneustes fossilis (Bloch) in Bangladesh: stocking density,floc volume,growth performance,and profitability     

Shamsuddin  Md  Hossain  M. Belal  Rahman  Moshiur  Kawla  Mst. Salamun  Shufol  Md. Badiul Alam  Rashid  Muhammad Mamunur  Md. Asadujjaman  Rakib  Md. Refat Jahan 《Aquaculture International》2022,30(2):1047-1070

Though Biofloc Technology is a new concept in Bangladesh, it provides advantages for improving aquaculture production in many countries, leading to achieve sustainable development goals. The objectives of this study were to determine the effects of stocking densities on the growth performance of stinging catfish (Heteropneustes fossilis) under Biofloc Technology and assess the economic prospects and business feasibilities. Fingerlings were stocked in unique 5000-L tanks with three stocking densities, i.e., 3500 fish/tank (Treatment-I), 4000 fish/tank (Treatment-II), 4500 fish/tank (Treatment-III). The treatments showed significant differences (P?<?0.05) considering the species-specific growth rate, feed conversion ratio, and protein efficiency ratio. Treatment-I had significantly ((P?<?0.05) higher final biomass (29.51 ± 0.04 kg/m³) than the other treatments. The present findings revealed that using a lower stocking density, the Biofloc Technology reduced ammonia (NH₃), nitrite (NO₂), nitrate (NO₃), TDS, and floc volume but significantly increased the dissolved oxygen. As a result, Treatment-I had generated significantly higher net income (BANGLADESHI TAKA—BDT 86,278.90) over the other treatments. Moreover, the NPV, net BCR, and RoR with 4% and 9% opportunity cost were also significantly higher in Treatment-I than other treatments. The internal rate of return (IRR) and SWOT analysis index indicates that investing in Biofloc Technology is far superior, and a stocking density of 3500 fish/tank (Treatment-I) resulted in a faster investment return.

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Fecal carriage of multi-drug resistant and extended spectrum β-lactamases producing E. coli in household pigeons,Bangladesh     

Badrul Hasan  Kamrul Islam  Murshidul Ahsan  Zakir Hossain  Mahmudur Rashid  Bibhas Talukder  Kabir Uddin Ahmed  Björn Olsen  Mohammad Abul Kashem 《Veterinary microbiology》2014

Antibiotic resistance and ESBL constitute a risk to human and animal health. Birds residing close to humans could mirror the spectrum of human associated antibiotic resistance. Household pigeons were screened in Bangladesh to shed light on human associated, as well as, environmental antibiotic resistance. Escherichia coli from pigeons (n = 150) were tested against 11 antibiotics. 89% E. coli isolates were resistant to one or more critically important human antibiotics like ampicillin, cefadroxil, mecillinam, ciprofloxacin, gentamicin and tigecycline. No carbapenamase-producers were detected and the lower ESBL prevalence (5%) in pigeons. ESBL-producing E. coli isolates had bla_CTX-M-15 genes. Pigeons shared some bacterial clones and had bird associated sequence types like E. coli ST1408. Fecal carriage of bacteria resistance of critically important human antibiotics, together with examples of shared genotypes among pigeons, indicate the human-birds and bird to bird transmissions are important in the epidemiology of antibiotic resistance.  相似文献   

Conservation of a Tropical Wet Semi-evergreen Forest Ecosystem by an Indigenous Community in the Bandarban Hill District of Bangladesh: The Role of Intervention     

Md. Danesh Miah  Farid Uddin Ahmed 《Small-Scale Forestry》2014,13(3):319-331

Indigenous communities in the Chittagong Hill Tracts (CHT) of Bangladesh had been conserving small patch of forests, commonly called village common forests (VCFs), especially for drinking water and non-timber forest produce. The size of VCFs has been decreasing, due to increasing population and conversion of forests for shifting cultivation. To restore the degraded forest resources and conserve the forest ecosystems in the VCF of the CHT, an intervention was undertaken in Bandarban, Bangladesh by Arannayk Foundation, an organization established jointly by the Government of Bangladesh and the United States of America. A training program on leadership, organizational development and alternative income generating activities was implemented to build the capacity of the members of the VCF management committee. The impact of the interventions was measured at the end of third year. Incomes of VCF-dependent communities were found to increase with resultant reduction of their dependence on VCFs. The intervention encouraged women’s participation in forest management and facilitated a written format of the constitution of the VCF management. The study identified that more training and awareness-raising activities are needed to ensure sustainability of the interventions. Mobilizing funds for the communities for sustainable alternative livelihoods was found effective. Appropriate compensation for conservation was found to make the restoration and conservation activities sustainable.  相似文献   

Increasing Tree Cover in Degrading Landscapes: ‘Integration’ and ‘Intensification’ of Smallholder Forest Culture in the Alutilla Valley,Matiranga, Bangladesh     

Syed Ajijur Rahman  Md Faizar Rahman  Terry Sunderland 《Small-Scale Forestry》2014,13(2):237-249

Research was conducted in Alutilla Valley in eastern Bangladesh to identify the nature of existing agroforestry systems and to identify potential agroforestry models that could ameliorate currently degrading forest resources Data were collected through farmer participatory research and a structured quarterly survey in two villages. Qualitative and supplementary quantitative analysis methods were used to assess the financial potential of agroforestry systems. Various patterns of agroforestry exist in the study site, but all have two common principles, namely ‘integration with agriculture’ and ‘multi-functionality’. Two agroforestry models suitable for adoption by farmers have been identified. Multi-strata agroforestry, based on a fruit and timber tree canopy with vegetables and tuber species in the understorey, can be practiced in the shifting cultivation fields near settlements. Fruit and timber tree-based conservation agroforestry is well suited to manage large-scale biologically depleted landscapes. Both systems yield early financial returns, facilitating the change from shifting cultivation to multi-strata agroforestry or fruit and tree-based conservation agroforestry.  相似文献   

Protein Requirements of the Freshwater Prawn Macrobrachium rosenbergii Evaluated by the Factorial Method     

Shin-Ichi  Teshima  Shunsuke  Koshio  Manabu  Ishikawa Md. Shah  Alam Luis Hector  Hernandez Hernandez 《Journal of the World Aquaculture Society》2006,37(2):145-153

The dietary protein requirement of the freshwater prawn Macrobrachium rosenbergii to obtain the maximum body protein retention was assessed by the estimated protein needed daily for maintenance (M) and body protein increment (G). The body protein increment was estimated by quantifying body nitrogen increments when the prawn was fed high‐protein diets composed primarily of casein. The protein required for maintenance was estimated by regressing weight gains in feeding experiments using graded dietary levels of casein. The true daily retention (R) or increase in body protein of the prawn corresponds to the sum of M and G. The values of M, G, and R determined in the present study were 3.86, 0.24, and 4.10 g/kg body weight/d, respectively. On the basis of the daily body protein increment and the net protein utilization of casein (58%), dietary protein requirement of the juvenile M. rosenbergii for maximum body protein retention was suggested to be about 7.1 g/kg body weight/d.  相似文献