Mohammad hamed Shojaie; Amir Hooman Hemmasi; Mohammad Talaei poor; Esmail Ghasemi
Abstract
Utilization of ionizing rays like gamma-ray in polymers to correct their properties has attracted so much attention from researchers. Therefore, in this study, polypropylene as the composite matrix, maleic anhydride (MAPP) as the compatibilizer material, and poplar wood as the filler were placed under ...
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Utilization of ionizing rays like gamma-ray in polymers to correct their properties has attracted so much attention from researchers. Therefore, in this study, polypropylene as the composite matrix, maleic anhydride (MAPP) as the compatibilizer material, and poplar wood as the filler were placed under the radiation of gamma-ray with different doses from 0 to 75 kGy. The white rot fungi (Trametes versicolor) and, brown rot fungi (Gloeophyllum Trabeum) were used in fungal decay test. The main purpose of this study is to investigate the probable benefits of gamma-ray radiation for improvement of some of the composites physical and mechanical properties, and also, to investigate the biodegradation in fungal decay and thermal properties. The results indicates that radiation of gamma-ray improves the physical and mechanical properties of some structures, and the decay resistance of the WPCs against brown and white rot fungus according to their weight losses. The uniformity of the micrographs obtained from the scanning electron microscope (SEM) indicated that the interaction between the polymer and wood fibers.
Mostafa Kohantorabi; Amir Hooman Hemmasi; Mohammad Talaei poor; Mehran Roohnia; Behzad Baziyar
Abstract
One of the problems of non-destructive tests in the detection of the inhomogeneities in wood and wood products is their location relative to the vibrating node and antinode. Thus, the hidden inhomogeneities located at the vibration node in such materials may not have any effects on the dynamic modulus ...
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One of the problems of non-destructive tests in the detection of the inhomogeneities in wood and wood products is their location relative to the vibrating node and antinode. Thus, the hidden inhomogeneities located at the vibration node in such materials may not have any effects on the dynamic modulus of elasticity and may not be detectable. In this study, we investigated the development of simple end-to-end joint in oak beams (Quercus castaneifolia) with dimensions of 72×4×2 cm (longitudinal×Radial×Tangential), with blocks removed from the areas of 0.06 and 0.50 cm of the beam length. The blocks were removed from the same beam as the joint was developed. The results indicated that developing a joint in 0.50 cm of the beam length has no significant effect on values obtained from the dynamic modulus of elasticity while creating this joint in 0.06 cm of the beam length has a significant effect on values obtained from the dynamic modulus of elasticity. Also, in both joints, the damping and acoustic converting efficiency values were increased and decreased, respectively. The amount of these changes was more in the area of 0.06 cm of beam length. In general, it can be said that due to the effect of vibrating node and antinode and on the other hand, the location of the joint in both areas, the acoustic conversion efficiency factor is a suitable factor to estimate the location of the joint or the inhomogeneity itself.
Mojtaba Asadi; Behzad Bazyar; Amir Hooman Hemmasi; Mohammad Talaeipour; Ismail Ghasemi
Abstract
AbstractThe paper aims to study differential, dynamic-mechanical and biodegradability analysis of polylactic acid/wood fiber (PLA) composites using three levels of nano-graphene (0.75, 1.5 and 3%). In order to mix the materials together and to make standard specimens, an internal mixer and pressure press ...
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AbstractThe paper aims to study differential, dynamic-mechanical and biodegradability analysis of polylactic acid/wood fiber (PLA) composites using three levels of nano-graphene (0.75, 1.5 and 3%). In order to mix the materials together and to make standard specimens, an internal mixer and pressure press were used. In the analysis of differential polishing calorimeter, the addition of fibers as well as nano-graphene had a positive effect on the glass transition temperature and the degree of crystallinity, which indicates a change from softness and flexibility to hardness and hardness. Dynamic-mechanical analysis has shown that the addition of wood fibers to pure polylactic acid can case an increase in the storage modulus of the composite and with the addition of nano-graphene to increasing composition, while the highest amount of storage modulus was related to polylactic acid composites / 30% of fibers and 30% of fibers. Results of tan δ peak showed that with the presence of wood fibers and nano-graphene, the temperature was transferred to a higher temperature and the limited movement of molecules due to the improvement of the fiber reaction in the PLA polymer. The results of biodegradability test also showed that the addition of fibers to pure PLA caused a significant increase in the weight loss of the composite. Additionally, nano-graphene to PLA composites decreases with the less weight in composites.
Yashar Einollahi; Amir Hooman Hemmasi; Habibollah Khademi Eslam; Esmaeil Ghasemi; Mohammad Talaei poor
Abstract
Considering the increase of environmental pollutant resulted from agglomerating rubbish and wastes containing stable petroleum-based polymers, substitution of these polymers with bio-polymers and solving their problems and defects in the production process as well as the final products is an important ...
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Considering the increase of environmental pollutant resulted from agglomerating rubbish and wastes containing stable petroleum-based polymers, substitution of these polymers with bio-polymers and solving their problems and defects in the production process as well as the final products is an important topic. In this study, the possibility of the production of poly lactic acid (PLA)-rice husk composite with acceptable properties, and also the effect of using flame retardant mineral fillers of aluminum three hydrates (ATH) and magnesium di-hydroxide (MDH) on physical and thermal properties of the produced composite were investigated. Results indicated that the density of PLA-rice husk composite was higher than petroleum-based polymers composites (PP/HDPE-rice husk composites); and flame retardant mineral fillers addition led to an increase in the composite density. Also, flame retardant mineral fillers addition decreased the composite water absorption and thickness swelling, in a way that they were comparable with petroleum-based polymers composites. Results of thermal gravimetric analysis (TGA) showed that flame retardant mineral fillers addition also decreased the temperature of the composite weight loss curve peaks, and the weight loss rate toward temperature rising.
Mohammad Ali Hossein; Mohammad Talaeipoor; Amir Hooman Hemmasi; behzad baziyar; Saeed Mahdavi
Abstract
The effect of applying the sequence of enzymatic treatment and refining was investigated on the properties of deinked pulp from mixed office waste paper (MOW). Refining was applied for 700 and 1500 revolutions. Enzymatic treatment was applied for 60 minutes with temperature of 60°C and 13% of consistency. ...
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The effect of applying the sequence of enzymatic treatment and refining was investigated on the properties of deinked pulp from mixed office waste paper (MOW). Refining was applied for 700 and 1500 revolutions. Enzymatic treatment was applied for 60 minutes with temperature of 60°C and 13% of consistency. Applying enzymatic treatment led to decrease in strength properties of paper and also decrease in freeness of the pulp. The refining process resulted in increase of paper properties and decrease in freeness of the pulp. By applying enzymatic treatment before refining, the freeness of pulp changed significantly so that, the freeness of the pulp was 496 and 390 for 700 and 1500 refining revolution respectively just for refining but these numbers changed to 397 and 544 for same revolutions for “enzymatic treatment + refining” sequence. In a normal condition increase of refining revolution lead to decrease in pulp freeness but that was interestingly the freeness increased for 1500 refining revolution. This means that the enzymatic treatment was effective. Generally, refining itself improved the quality parameters of pulp and paper, but applying this process after enzymatic treatment changed everything.
Amir Mollahassani; Amir Hooman Hemmasi; Habibollah Khademi Eslam; Amir Lashgari; behzad baziyar
Abstract
The aim of this study is to evaluate the dynamic and static of elastic properties of Fir wood joints. For this purpose conventional joints in woos industry including dovetail, tongue and groove beech wood (Abies alba.) joints with polyvinyl acetate (PVA) and cyanoacrylate (CA) adhesives were used. Dimensions ...
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The aim of this study is to evaluate the dynamic and static of elastic properties of Fir wood joints. For this purpose conventional joints in woos industry including dovetail, tongue and groove beech wood (Abies alba.) joints with polyvinyl acetate (PVA) and cyanoacrylate (CA) adhesives were used. Dimensions of research samples were determined 24×50×360 (mm) according to international standard (ISO No.3129), and the results indicate that the effects of joint type, adhesive type, joint size, and also retrospective joint size became meaningful at 5% level in dynamic and static tests. As the length of groove and height of dovetail and length of dowel increased in the joints, dynamic and static elasticity modules increased, and in terms of changes in elasticity modules of the research. Elasticity module for dovetail joint, as a result of the shape, having a homogenous joint texture, and also lack of extended adhesive line in the joint, is closer to un jointed samples (control group). Also cyanoacrylate adhesive improved elasticity features of samples compared to polyvinyl acetate adhesive as a result of higher tension resistance and faster coagulation. The results of the Student's t-test indicate that there exists a not significant difference between the mean of dynamic and the mean of static modulus of elasticity, not significance at 5% level and The Pearson correlation test indicate that the dynamic and static modulus of elasticity of the samples are significant at 5% level and are of positive correlation(+.0958) .With regard to the correlation of the results of dynamic and static tests, methods for non-destructive dynamic investigation may be regarded as appropriate alternatives to destructive static tests, in order to assess and classify woods.
Amir Homan Hemmasi; mostafa kohantorabi
Abstract
In this study the relationship between dynamic modulus of elasticity from longitudinal vibration method with static modulus of elasticity and bending strength in two directions: the Parallel machine direction and machine direction have been investigated. For this purpose 4 plates ...
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In this study the relationship between dynamic modulus of elasticity from longitudinal vibration method with static modulus of elasticity and bending strength in two directions: the Parallel machine direction and machine direction have been investigated. For this purpose 4 plates of particleboard with dimensions 124× 90 ×1.6 cm (length× width× thickness) were selected and free longitudinal vibration test in PMD and MD were performed on each plates. After that the primary plates were cut to four plates with dimensions 62× 44 ×1.6 cm (length× width× thickness) and longitudinal vibration test in PMD and MD were performed on each plates again. Finally each plates were cut to the beams with dimensions 36× 1.6 ×1.6 cm and longitudinal vibration test and and static bending test were performed on them. The results show that good correlation between dynamic modulus of elasticity from longitudinal vibration test and static modulus of elasticity and bending strength (result of beams extracted from each plates) in both size of plates in two size (124× 90 ×1.6 and 62× 44 ×1.6 cm) and beams extracted from each plates in two directions (PMD and MD). In addition there was good correlation between dynamic modulus of elasticity of longitudinal vibration from two size plates (124× 90 ×1.6 and 62× 44 ×1.6 cm). When the samples smaller than primary plates, the dynamic modulus of elasticity values were increased, that it due to the diffusion of waves in samples with larger dimensions. In general, according to results of this research it can be concluded that by applying the appropriate correction factors, longitudinal vibration method an efficiency method for calculation of dynamic and static modulus of elasticity and estimate of the modulus of rupture in plates in full sized.
Composite wood products
Hassan Ziaei Tabari; Habibollah Khademieslam; Behzad Bazyar; Amir Homan Hemmasi
Abstract
A new kind of thermoplastic elastomer nano composite reinforced with nano cellulose fibers is reported. The first aim of this investigation was to study the interaction and dispersion of nano cellulose fiber into Pebax matrix. This copolymer is Polyether – b – Amide thermoplastic elastomer ...
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A new kind of thermoplastic elastomer nano composite reinforced with nano cellulose fibers is reported. The first aim of this investigation was to study the interaction and dispersion of nano cellulose fiber into Pebax matrix. This copolymer is Polyether – b – Amide thermoplastic elastomer which is synthetized from renewable resources, and its hydrophilic character allows it to interact with nano cellulose. The interaction and reinforcement effect of nano cellulose at 3 levels of nano cellulose (1%, 3% and 5%) were examined by Scanning electron microscopes (SEM), Fourier transform infrared spectroscopy (FTIR) and Mechanical tests (young module, elongation at break and impact resistance). The results achieved from these tests were indicating appropriate effects of nano cellulose fibers for the strong interaction and close contact with polyamide phase of Pebax polymer which caused high mechanical properties (at 3% of nanoellulose) in nano composites. The young module and impact resistance of nano composite were significantly increased.
Management and Economics wood
Amir Tavakkoli; Amir Hooman Hemmasi; Mohammad Talaeipour; Behzad Bazyar; Ajang Tajdini
Abstract
The objective of the research is to forecast the trend of the printing and writing paper consumption in Iran for a five-year period using both modern and classical methods. In order to do the forecasting, predictability of time series was primarily studied using Durbin-Watson and Runs tests. Then, artificial ...
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The objective of the research is to forecast the trend of the printing and writing paper consumption in Iran for a five-year period using both modern and classical methods. In order to do the forecasting, predictability of time series was primarily studied using Durbin-Watson and Runs tests. Then, artificial neural network model (multilayer perceptrons (MLP)) and univariate and multivariate classical forecasting models such as univariate single exponential smoothing (SES), double exponential smoothing (DES), holt-winters exponential smoothing (HWES) and Box- Jenkins (ARIMA) models, and multivariate econometric model all together were compared in terms of the standard statistical measures. Finally, the consumption of printing and writing paper in Iran was forecasted up to the year 2017 using the most appropriate model. The results of both the parametric test of Durbin-Watson and non-parametric test of Runs show that, the printing and writing consumption series is non-random and predictable. The results of comparing different forecast methods showed that the artificial neural network model has higher forecasting accuracy than the classical models and it is more appropriate for the five-year forecast period. Also, the results of forecasting by using neural network model (MLP), revealed that the printing and writing paper consumption in Iran is forecasted to increase by 5.3%, from around 375 thousand tons in 2012 to 420 thousand tons in 2013, but it falls over the five-year forecast period, from 5.3% in 2013 to 0.07% in 2017.
Composite wood products
Mehdi Kalagar; behzad baziyar; Habibalah Khademislam; Esmaeil Ghasemi; Amir homan Hemmasi
Abstract
In this paper, poly lactic acid (PLA)/ wheat straw fibers manufactured by twin screw extruder and molding compression have been studied. Wheat straw fibers were treated with trietoxymethel silane for better compatibility between two phases. Physical properties, tensile properties of the composites were ...
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In this paper, poly lactic acid (PLA)/ wheat straw fibers manufactured by twin screw extruder and molding compression have been studied. Wheat straw fibers were treated with trietoxymethel silane for better compatibility between two phases. Physical properties, tensile properties of the composites were analysis. The effect of the wheat straw fibers on the thermal properties of PLA has also been investigated in DSC experiments. The effects of silane treatment on the wheat straw fibers have been analyzed by FTIR. Scanning electron microscopy from samples surface were used for better study of water absorption and thickness swelling. Composites wheat straw fiber were treated shows signification lower water absorption and thickness swelling than composites PLA/ untreated wheat straw fibers. The lower amount of water absorption and thickness swelling occurred in the pure PLA. The existence crack and break occurred in the surface of PLA/ untreated wheat straw fibers composites after immersion in the water indicating higher water absorption and thickness swelling were in these samples. Wheat straw fibers were treated with silane due to better wetting and better linkage in the interfacial surface with PLA matrix showed higher tensile properties then PLA/ untreated wheat straw fiber composites. Differential scanning calorimeter test showed that with addition wheat straw fibers were treated to pure PLA the increased glass transition temperatures. The nucleating effect of wheat straw fibers, special treatment with silane cause to increased in the crystallization temperature composites than pure PLA which a positive effect showed on the degree of crystallization.
