Editorial
Research Paper
Mohammad Ghofrani
Abstract
AbstractIn this study, alumina nanoparticles was added to clear varnishes (Sealer, clear, semi-polyester and polyurethane), and changes in adhesion strength on wood specimens of Walnut (Juglans Regia) and spruce (Picea Spp) were studied. The experimental samples were prepared from defect-free woods with ...
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AbstractIn this study, alumina nanoparticles was added to clear varnishes (Sealer, clear, semi-polyester and polyurethane), and changes in adhesion strength on wood specimens of Walnut (Juglans Regia) and spruce (Picea Spp) were studied. The experimental samples were prepared from defect-free woods with size of 300×100×10 mm and dried to 8 % moisture content in air drying and Killen drying, respectively. The samples surfaces finished and the clear varnishes applied on samples surfaces using pneumatic spry gun and the adhesion strength test was done on samples. The result of this study showed that the highest adhesion strength was observed in polyurethane varnishes with 6% alumina nanoparticles in walnut wood, and the lowest adhesion strength observed in cellulosic varnishes (sealer and clear) with 0% nanoparticles in spruce wood. It can be concluded that with the control of nano alumina percentage in varnishes in a defined level, the adhesion strength of the clear varnishes increased. Also, with improvement of varnishes’ adhesion strength on wood surface, the varnishes durability increased, consequently.
Research Paper
nazanin salehi; Javad Torkaman; ramin naghdi; Mehran Roohnia
Abstract
The knot is the branch impact on the tree's trunk which reduces the quality of the wood. Knots or occlusion branches are the most important factor in the grading of woods. The purpose of this research is to detect and distinguish the size of the knot in the beech tree stem by non-destructive stress wave ...
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The knot is the branch impact on the tree's trunk which reduces the quality of the wood. Knots or occlusion branches are the most important factor in the grading of woods. The purpose of this research is to detect and distinguish the size of the knot in the beech tree stem by non-destructive stress wave method. In this research, five one-meter stems were examined and according to the knot size, the stems were classified into four parts without knots, with small, medium and large knots. By using the FAKOPP microsecond timer device, stress waves were passed along the length of the stem and the width of the knots in the four parts of the stem. The amount of the stress waves velocity were calculated according to the transit time of the stress waves and also percentage of the Relative Velocity decrease of Stress waves were calculated. Analysis variance of the data showed between the four parts there is a significant difference at the 95% confidence level. The results showed that the size of knot has effective on the Relative Velocity decrease of Stress waves in the beech tree stem. As the knot gets bigger, its angle decreases with the main stem axis. consequently more length is placed in the stem, and the speed of its occlusion increases. In this method,very small knots whose percentage of the Relative Velocity decrease of Stress waves was less than 10% were not detected. Therefore, for small, medium and large knots, the range of Relative Velocity decrease of Stress waves were obtained 10-20%, 20-45% and more than 45%, respectively.
Research Paper
Ali Hasanpoor tichi; Hadi Gholamiyan
Abstract
In this study , Effect of nano cellulose Fiber gel bacteria as reinforcer on physical, mechanical and morphological properties of composites made of bagasse and cement has been studied. Nano variable factors in three levels (0, 1 and 3 % by weight of cement), the mixing ratio of bagasse as lignocellulosic ...
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In this study , Effect of nano cellulose Fiber gel bacteria as reinforcer on physical, mechanical and morphological properties of composites made of bagasse and cement has been studied. Nano variable factors in three levels (0, 1 and 3 % by weight of cement), the mixing ratio of bagasse as lignocellulosic material with Portland cement, in three levels (90:10, 80:20, 70:30%) was equal to the dry weight of cement. The target density 1.1 g/cm3 and 5% calcium chloride for all treatments were considered as Fixed factors. The mechanical and physical properties of composites includes modulus of rupture, modulus of elasticity, internal bonding, thickness swelling after 2 h and 24 h immersion in water and density of boards were measured according to the standard DIN-EN-634. In this study, to investigate the morphological properties of composites and how to distribute Nano, microscopic images (SEM) were taken from the broken cross-section of the samples. The results showed that boards made with nano fiber cellulose had more modulus of rupture, modulus of elasticity and internal bonding. The results also showed that with increasing nano, density, dimensional stability of the boards and heat hydration of cement mortar increased. The results from microscopic imaging (SEM) showed that cellulose nanofiber can fill the pores of the composite and create a uniform structure, thus improved the strength of the boards.
Research Paper
Reza Hajihassani; seyedeh masoomeh; Saman Ghahri; Kamyar Salehi
Abstract
AbstractThe purpose of this study was to investigate the effect of heat treatment on bio-durability and some physical and mechanical properties of beech (Fagus Sp.) and pine (Pinus Sp.). Thermo-wood samples were prepared from beech and pine species based on thermo-D process. Heat-treated and untreated ...
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AbstractThe purpose of this study was to investigate the effect of heat treatment on bio-durability and some physical and mechanical properties of beech (Fagus Sp.) and pine (Pinus Sp.). Thermo-wood samples were prepared from beech and pine species based on thermo-D process. Heat-treated and untreated wood specimens were evaluated after exposing to brown rot fungus for 16 weeks. The laccase activity and its effect on mass loss and wood density were investigated. Results showed that deterrence value of heat treatment on mass loss caused by brown rot fungus have been 76.92% and 44.32% in beech and pine wood, respectively. So, laccase activity and its efficiency on mass loss of control specimens was more than heat treated wood. The results also showed that thermally modification at high temperatures reduced wood density. However, it had deterrent effect on decrease of density caused by brown rot fungus activity. Moreover, some mechanical properties including impact strength and compression parallel to grain of wood specimens were measured. The results generally showed that thermal modification improves the bio-durability of both wood species. The results also revealed reduction of mechanical properties due to heat treatment except compression parallel to grain.
Research Paper
alireza ziapour; zahra Kazemi Karchegini; negin Kazemi Karchegini
Abstract
The color of wastewater is considered as a major environmental problem. Chemical and biological treatment of dye containing wastewater is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices ...
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The color of wastewater is considered as a major environmental problem. Chemical and biological treatment of dye containing wastewater is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers are trying to find available low-cost materials with high adsorption. In this research, soybean lignocellulosic waste has been investigated for absorption of Rimosol Black B (RBB) dye. First, the effect of dye RBB concentration, pH, temperature and contact time on the absorption value was investigated, and then the adherence of the adsorption isotherm to the Langmuir and Freundlich models was investigated. The results showed that the absorption efficiency depended strongly on pH and slightly on the temperature. The absorption rate of RBB dye with soybean residue is high and the absorption is complete in a short period of time. The results of the adsorption isotherm analysis showed that both models are suitable for describing the adsorption of RBB dye with soybean. The maximum absorption capacity of RBB dye by soybean waste was calculated 90.9 mg/g, which is more than some cheap absorbents studied and less than others such as rapeseed lignocellulosic waste.
Research Paper
Reza Ghaffari Sani; Foroogh Dastoorian; seyed Majid Zabihzadeh; Mohammad Tasooji
Abstract
In recent years, plant oils usage as matrix in natural fiber reinforced polymer composites, has been considered because of increasing environmental concern. In the present research work, acrylated epoxidized soybean oil combined with maleic anhydride and styrene as a matrix and wheat straw flour as filler ...
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In recent years, plant oils usage as matrix in natural fiber reinforced polymer composites, has been considered because of increasing environmental concern. In the present research work, acrylated epoxidized soybean oil combined with maleic anhydride and styrene as a matrix and wheat straw flour as filler was used for making a relatively biodegradable composite. In order to find the optimum synthesis time of resin, during reaction of maleic anhydride with acrylated epoxidized soybean oil, three time level of 60, 90 and 120 min, polymer was prepared and cross link density was determined with “solvent swelling” method. The optimum synthesis time of resin was obtained 90 min. Afterwards, maleated acrylated epoxidised soybean oil was mixed with 25% of styrene and 60 mesh wheat straw flour in three weight ratio of 20, 30 and 40% manually. The combination of resin and wheat straw flour was poured in a steel mold and pressing was applied manually. The die was placed in an oven at temperature of 140oC for one hour. Infrared spectroscopy, Thermogravimetric analysis tensile and impact test was conducted to evaluate and analyze the physical and mechanical properties of the resulted composite. Infrared spectroscopy results showed ether bond formation between hydroxyl groups of wheat straw and carbonyl groups of resin. Water absorption test results showed no statistical difference between water absorption values of three loading of wheat straw till 144 hours of immersion, however at 168 hours of immersion, water absorption values were increased with increase of wheat straw loading. There was no statistical difference between thickness swelling values of composites with different wheat straw loading. With increasing wheat straw loading, tensile strength and modulus was increased significantly. Also the impact strength increased as an increase of wheat straw loading.
Research Paper
Majid Salehi; Mohammad Talaei poor; Habibollah Khademi Eslam; Behzad Bazyar
Abstract
The use of various pretreatments, including the torrefaction process, in order to increase the efficiency and optimize the consumption of fuel briquettes, have attracted a lot of attention in recent years. Therefore, in this research, torrefaction pretreatment at 180 ºC temperature was used to modify ...
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The use of various pretreatments, including the torrefaction process, in order to increase the efficiency and optimize the consumption of fuel briquettes, have attracted a lot of attention in recent years. Therefore, in this research, torrefaction pretreatment at 180 ºC temperature was used to modify bagasse biomass. In addition, lignin binding agent was used at levels of 2, 5 and 10%. Fuel briquettes weighing 30 grams were prepared using a manual briquetting machine. The physical, resistance and thermal characteristics of the resulting briquettes were investigated. The results showed that torrefaction pre-treatment by increasing the volumetric density of the resulting briquettes and increasing the amount of fixed carbon up to about 50% was able to increase the heating value of the briquettes up to about 10%, on the other hand, this process led to a decrease in the compressive strength of the resulting briquettes, which is used lignin as a binding agent could compensate a significant amount of this resistance drop. The results showed that the number of volatile substances of briquettes was reduced by 9% with torrefaction pre-treatment, which has a significant effect on reducing the pollution of these briquettes. In the study of the effect of lignin, it was also observed that with the increase in the consumption of lignin, the density and calorific value also increased. In general, the results of this research show that the use of lignin binding agent together with torrefaction pre-treatment can make possible the production of high-quality fuel briquettes from bagasse.
