Research Paper
Physics and Mechanical Wood
Saeed Mahdavi
Abstract
The use of renewable energies, such as biomass, is becoming increasingly important as countries realize that bioenergy present an approach to their international commitments to reduce greenhouse gas emissions. Biomass with higher thermal energy value and optimal composition is more desirable for the ...
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The use of renewable energies, such as biomass, is becoming increasingly important as countries realize that bioenergy present an approach to their international commitments to reduce greenhouse gas emissions. Biomass with higher thermal energy value and optimal composition is more desirable for the thermal conversion systems. In present investigation, properties of ten type's wood biomass relevant to combustion were evaluated. Important characteristics requiring analysis for the biomass were moisture and ash content, volatile matter, elemental composition (C, H, N, S, and O), and high and low heating values (HHV and LHV). The heating value has been determined based on experimental and computational methods by colorimeter bomb and elemental content, respectively. The results showed that eldarica pine biomass had the highest content of biomass sulfur, which is undesirable environmental factor in the bioenergy system. Regarding to the fixed carbon to volatile matter ratio, Citrus sinensis var. thomson has the lowest ratio, so it is the best biomass for the gasification process. The highest and lowest heating values were determined for the poplar pruning residues (group a) and apple (group b and c), respectively. The highest and lowest of HHV and LHV were measured for P. deltoides and Malus spp., respectively.
Research Paper
Mechanical conversion of wood and wooden fittings
Hadi Gholamiyan
Abstract
In this study, the effect of corona treatment on improving the durability of nitrocellulose and polyurethane coatings used in the wood furniture industry before and after weathering investigated. The boards made from poplar and beech were coated by an automatic film applicator after corona treatment ...
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In this study, the effect of corona treatment on improving the durability of nitrocellulose and polyurethane coatings used in the wood furniture industry before and after weathering investigated. The boards made from poplar and beech were coated by an automatic film applicator after corona treatment and accelerated for 30 days in a weathering machine. Then, the contact angle, abrasion resistance, and pull-off adhesion testing to the wood surface coatings were analyzed. The results showed that corona treatment reduced contact angle in wooden species and the highest contact angle reduction found in beech wood. Also, the results of the adhesion test showed that the highest adhesion was related to the polyurethane coating and after weathering, the adhesion of the coatings decreased, but the use of corona treatment, in addition to increasing the adhesion strength before weathering, could significantly improve adhesion after weathering. The results of the abrasion test showed that the wear resistance increased in wooden species due to the coating, and the highest amount observed in the beech-coated with polyurethane. After weathering, wear resistance was reduced in all samples, but using corona treatment increased resistance to abrasion. In general, it can say that the use of corona treatment can significantly (95%) improve the resistance to mechanical properties and durability of coatings before and after weathering and thus increase the durability of the furniture and wooden structures.
Research Paper
Composite wood products
Salume Esmaeilzadeh Saeih; Habibollah Khademi Eslam; Esmaeil Ghasemi; behzad baziyar
Abstract
Abstract Effects of temperature, cellulose Nano fibers and Nano clay particles on mechanical, physical and morphological properties of biodegradable composites made of recycled thermoplastic starch biopolymer and regular mixed industrial sawdust are investigated. To this aim Cellulose Nano Fibers and ...
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Abstract Effects of temperature, cellulose Nano fibers and Nano clay particles on mechanical, physical and morphological properties of biodegradable composites made of recycled thermoplastic starch biopolymer and regular mixed industrial sawdust are investigated. To this aim Cellulose Nano Fibers and Nano Clay particles were selected to be 0, 3 and 5 weight percent and were added to prepared biodegradable composites by using internal mixer and samples prepared by injection molding. Mechanical properties including tensile modulus and strength, flexural modulus and strength were extracted at temperatures ranging from 23 ºC to 80 ºC. Impact test and water absorption and thickness swelling were also performed according to related standards. Results show that elevating the temperature drastically reduce mechanical properties. Nano Clay addition results in better mechanical properties except for impact and water absorption and thickness swelling are improved. Using 5% Cellulose Nano Fibers improves mechanical and morphological properties better than 3% addition. Dynamic mechanical thermal analysis revealed Nano composites samples with 5% Nano Clay and Cellulose Nano Fibers has higher storage modulus and glass transition temperatures in compare to pure composite samples. This Nano particles can be successfully used to improve properties and performance except for fracture resistance.
Research Paper
Physics and Mechanical Wood
Hadi Dashti; Kambiz Pourtahmasi; asghar tarmian
Abstract
In this research, the effect of preheating in nitrogen medium on acoustic properties of walnut and white mulberry’s boards was studied. Sapwood boards of 300×20×20 mm with the green moisture content were prepared. Heat treatments were applied at 140 and 160 oC under pressure of 2 pascal ...
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In this research, the effect of preheating in nitrogen medium on acoustic properties of walnut and white mulberry’s boards was studied. Sapwood boards of 300×20×20 mm with the green moisture content were prepared. Heat treatments were applied at 140 and 160 oC under pressure of 2 pascal for 30 and 60 minutes. Following the heat treatment, the samples were dried in a convectional laboratory kiln of 8% at 50 oC, relative humidity of 50%, and air velocity of 1 m/s to the average final moisture content of 8%. Using the free vibration method on free- free bar, the dynamic modulus of elasticity and damping factor were evaluated. Results revealed that the heat-treatment at 140 oC for 30 minutes did not have a significant effect on vibration properties of the wood samples. On the other hand, the heat-treatment at 160 oC caused a significant increase in dynamic modulus of elasticity and also a reduction in the damping factor of walnut and white mulberry samples. The FTIR spectroscopy and X-ray studies showed that the degradation of cell-wall polymers and increase in the crystallinity of the walnut wood specimens occurred due to heat treatment at 160 0C.
Research Paper
Chemistry of wood
Ramin Vaysi
Abstract
The aim of this study was accomplished on identification and comparison of chemical compounds in wood of maple tree. For this purpose, the samples were chosen randomly from persuan maple and Caucasian maple tree in Nowshahr's forest region. Then, flour and ash were provided from heartwood, sapwood of ...
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The aim of this study was accomplished on identification and comparison of chemical compounds in wood of maple tree. For this purpose, the samples were chosen randomly from persuan maple and Caucasian maple tree in Nowshahr's forest region. Then, flour and ash were provided from heartwood, sapwood of maple tree by TAPPI standards. For measured metallic ions, by atomic absorption method. The ions results showed that mn, co, fe, zn, and cu ions in Caucasian maple were more than persuan maple, but k ion was lower. Then extractives were separated from wood flour by acetone and extractives residue transferred to glass vial and was added BSTFA reactive agent to it. After samples prepared, samples were injected to the GC/MS device for it analysis. Identification of compounds was done by retention time of each compound, calculation of Quats index and Adams table. The result of GC-MS showed that there are 39 compounds in persuan maple, that benzaldehyde, bis (2-ethylhexyl)phthalate, gibberllin A3 and 1,2-benzenedicarboxylic acid were important components. 24 components identified in Acer leatum that di-limonene, bis(2-ethylhexyl)phthalate,alpha- terpen and alpha-pinene as important components. Comparison of chromatograms showed that di-limonene and bis(2-ethylhexyl)phthalate were exists as 2 common components in persuan maple and Caucasian maple tree. These compounds can very important in durability and consumption its.
Research Paper
Mona Otarod; Asghar Tabei
Abstract
This study was conducted to determine morphological characteristics and chemical components of sunflower stalks (Helianthus annus. Var, cheernianka 66) cultivated in Astara area. After collecting number of stalks, 6 stalks of the same size were selected to determine for morphological characteristics ...
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This study was conducted to determine morphological characteristics and chemical components of sunflower stalks (Helianthus annus. Var, cheernianka 66) cultivated in Astara area. After collecting number of stalks, 6 stalks of the same size were selected to determine for morphological characteristics and remaining stalks were used to determine the chemical components. Morphological tests were performed to determine fibers dimensions and biometric coefficients by sampling from 3 heights of stalks (5%, 50% and 75%).Maceration of fibers was done by Franklin method . Measurement of chemical components was performed on the basis of TAPPI standard in 2 modes such with bark and without bark. The total average of fiber length, fiber diameter, lumen diameter and fiber wall thickness were measured for this stalk as 663µm , 29.848 µm, 25.182 µm and 2.336 µm respectively. The total average of slenderness coefficient, flexibility coefficient and Runkel index of fibers were calculated as 22.681, 84.259 and 0.188 respectively. Average percentage of cellulose, lignin, acetone extractives, alcohol extractives, hot water extractives and ash for this stalk were measured as 40.066, 22.758, 3.953, 1.86, 2.186 and 3.208, respectively. The results showed that fibers length increased with increasing of stalk height, but this increasing was not significant. Fibers diameter, lumen diameter and fibers wall thickness decreased with increasing of stalk height, this decreasing was significant for fibers diameter and lumen diameter in the height of 75%, but it was not significant for fibers wall thickness. Also, the results showed that bark has significant effect on all of the chemical components, so that, the stalk with bark has lower cellulose and more lignin, extractives and ash in compare with the stalk without bark.
Research Paper
Composite wood products
Behzad Hosseini; mohammad ghofrani; Hamid Reza Taghiyari; Saman Ghahri
Abstract
In this research, Effect of soy flour addition into urea-formaldehyde resin on physical, mechanical properties and formaldehyde emission of plywood was investigated. Soy flour was mixed with urea-formaldehyde adhesive in three levels 5, 10 and 15% (based on dry weight of urea-formaldehyde adhesive) and ...
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In this research, Effect of soy flour addition into urea-formaldehyde resin on physical, mechanical properties and formaldehyde emission of plywood was investigated. Soy flour was mixed with urea-formaldehyde adhesive in three levels 5, 10 and 15% (based on dry weight of urea-formaldehyde adhesive) and three-layer plywood was manufacture from the resultant adhesive and poplar veneer. Properties of manufactured plywood including formaldehyde emission according to EN-717-3 standard, shear strength according to EN-314 standard and water absorption and thickness swelling according to EN-317 standard were investigated. The results indicated that addition of soy flour up to 15% decreased formaldehyde emission up to 29.34% and increased shear strength of panels. Moreover, delamination test (According to ANSI/HPV-HPV1 Standard) presented acceptable results. The results obtained from water absorption and thickness swelling after 2h and 24h showed that addition of soy flour increased the amount of water absorption and thickness swelling. thickness swelling after 2h and 24h showed that addition of soy flour increased the amount of water absorption and thickness swelling.
Research Paper
Composite wood products
ali hasanpoor tichi; Fardad Golbabaei; hadi Ghasemi; mojtaba rezanezhad
Abstract
In this study, the effect of nano gel wollastonite on physical, mechanical and morphological properties of composites made of bagasse and cement has been investigated. The mixing ratio of bagasse as lignocellulosic material with Portland cement at three levels (15:85, 25: 75 and 35: 65%) and nano-wollastonite ...
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In this study, the effect of nano gel wollastonite on physical, mechanical and morphological properties of composites made of bagasse and cement has been investigated. The mixing ratio of bagasse as lignocellulosic material with Portland cement at three levels (15:85, 25: 75 and 35: 65%) and nano-wollastonite at three levels of 0, 3 and 7% were considered as the variables of this study. The cake density of all boards were 1.1 g / cm3 and calcium chloride booster 5% for all treatments were considered as constant factors. Mechanical and physical properties of the specimens include modulus of rupture, modulus of elasticity, internal bonding, thickness swelling after 2 and 24 soaking hours in water and density of boards according to DIN-EN-634 and fire resistance (weight loss percentage) according to standard ISO-11925 were measured. In this study, the hydration temperature of a mixture of cement, bagasse and nano-wollastonite was measured using a thermocouple and flux. Also, microscopic images (SEM) of samples were prepared to investigate the morphological properties of composites and their distribution. The results showed that by increasing the amount of nano-wollastonite, the percentage of weight loss boards decreased, the heat of hydration and the physical and mechanical properties improved. The modulus of rupture, modulus of elasticity, and internal bonding of boards decreased with increasing bagasse content and the maximum value was obtained using 15% bagasse. The results also showed that with increasing bagasse content in boards, there was a significant increase in thickness swelling of boards. Inference from microscopic imaging (SEM) showed that the optimum level of nano-wollastonite can fill the empty holes and create a uniform structure and thus improve the properties of the boards.
Research Paper
Pulp and paper
Kajal Moradian Gilan; Sahab Hedjazi; Ali Abdulkhani; Herbert Sixta
Abstract
In this research, the effect of hot water and alkaline pre-extractions on properties of bagasse monoethanolamine-AQ pulps was investigated and the results were compared with that of soda pulping. The pre-extraction with alkaline charge of 10%, time of 30 min resulted in total yield and holocellulose ...
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In this research, the effect of hot water and alkaline pre-extractions on properties of bagasse monoethanolamine-AQ pulps was investigated and the results were compared with that of soda pulping. The pre-extraction with alkaline charge of 10%, time of 30 min resulted in total yield and holocellulose of 94.7% and 71.6%, respectively. The hot water pre-extraction with L/W of 10/1 and time of 45min lead to total yield and hollocellulose of 94% and 69.4%, respectively. These trails were selected as the optimum conditions. Monoethanolamine was used as pure and also in different proportions with water for cooking unextracted and pre-extracted bagasse. Variables in monoethanoleamine pulpng were ratio of monoethanolamine to water at three levels (100/0, 75/25, and 50/50%) and the ratio of the liquor to bagasse of 6 to 1, cooking time of 60 min, the temperature of 165°C and AQ charge of 0.1% considered as constant. According to the results, the MEA-AQ pulps produced with MEA/H2O ratio of 75/25 (from unextracted bagasse) have the highest total yield (61.9 %) and the acceptable kappa number (19.5). Pre-extraction resulted in improving of the yield in both MEA-AQ and soda pulping processes. After pre-extraction, the tensile index and breaking length of pulps dropped. In contrast, the tear index of pulps produced from pre-extracted bagasse in both pulping processes was increased. The brightness of soda pulps from un- and pre-extracted bagasse was more than that of MEA-AQ pulps. After pre-extraction, the opacity of pulps remains almost unchanged.
Research Paper
Physics and Mechanical Wood
Faezeh Farhadi; Seyed Majid Zabihzadeh; foroogh dastoorian
Abstract
Extensive application of heat treated wood in exterior uses with high relative humidity and high temperature circumstances, necessitates the study of mechanical and creep behavior of them at such situations. The general objective of the present study was investigating the effect of test temperature on ...
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Extensive application of heat treated wood in exterior uses with high relative humidity and high temperature circumstances, necessitates the study of mechanical and creep behavior of them at such situations. The general objective of the present study was investigating the effect of test temperature on creep behavior of heat treated velvet maple wood. Heat treatment was conducted on oven dried maple wood samples at three temperature levels of 160, 175 and 190oC. Four-point static flexural test was conducted for determination of the required load level for creep test in three replications at each treatment temperature levels. For conducting creep tests, three levels of test temperature of 21, 40 and 60oC and duration of 65 hours were considered. Results of flexural test showed that heat treatment led to decreasing the rupture modulus compared to the control one; however, the elastic modulus did not change significantly. Results of creep test showed that with increasing test temperature, instantaneous and creep compliance values increased. With increasing treatment temperature, creep compliance was increased as well. Anti-creep efficiency ratio for evaluating the effect of test temperature on creep value at different levels of treatment showed that generally heat treatment led to decreasing the creep strength compared to the control ones. Heat treatment at temperature of 160oC led to in improvement in creep behavior at higher test temperature, in which the reason was attributed to increase of cellulose crystallinity and lignin condensation reaction, in turn led to lower plasticization of wood at higher test temperature.
