Sana Lotfi; Mohammadali Saadatnia; Mohammad Hadi Moradian; ladan pour sartip
Abstract
Ensuring the quality and stability of trees as the most important components of the plant community has attracted the attention of foresters to identify and measure defects and ensure safety coefficients. Therefore, in the present study, the use of acoustic tomography to calculate the extent of decay, ...
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Ensuring the quality and stability of trees as the most important components of the plant community has attracted the attention of foresters to identify and measure defects and ensure safety coefficients. Therefore, in the present study, the use of acoustic tomography to calculate the extent of decay, the area of the woody section and the safety factor of black pine was studied. Acoustic tomography was performed using 16 sensors at two heights of 147 and 200 cm above the ground and on 8 tree specimens in the Sopron region of Hungary. The results showed that the stress wave technique was an accurate method for determining safety coefficients and determining the amount of internal decay in the tree and also had the ability to identify compression areas in cross section. Resistography of the studied sections in different geographical directions assisted to locating the woody areas, which was compatible with the information of acoustic tomography. The findings of this study showed that the area of the canopy has a significant role in the safety of the tree and the possibility of tree fall, so that in some trees due to their condition, with doubling the area of the canopy, the torque increased from 80827 to 161655 N.m and the condition of the tree changed from low-risk to high-risk.
Physics and Mechanical Wood
Mohamad ali Sadatnia; noshin sattari; mehran roohnia; mohsen bahmani
Abstract
The goal of this study was to determine the modulus of elasticity and modulus of rapture of two kinds of date palm (Khasi and Hajmohammadi) using static bending and dynamic (flexural vibration) techniques. To reduce the difference between static and dynamic stiffness values, the static bending modulus ...
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The goal of this study was to determine the modulus of elasticity and modulus of rapture of two kinds of date palm (Khasi and Hajmohammadi) using static bending and dynamic (flexural vibration) techniques. To reduce the difference between static and dynamic stiffness values, the static bending modulus of elasticity was modified by taking into account the value of the shear deflection. In addition to, for better understanding of the mechanical properties of date palm, values were compared with those measured for poplar samples. The results showed that, in Khasi the mean values of the modulus of elasticity obtained by flexural vibration, the static modulus of elasticity, the modified static modulus of elasticity and as well as the modulus of rapture were 47, 67,68 and 38% less than those measured for Hajmohammadi respectively. In comparing with date palm, values measured for poplar samples were more pronounced. The difference between dynamic and static values of modulus recorded for Khasi, Hajmohammadi and poplar samples were 63, 40 and 19% respectively. After modification of the static values, the difference was reduced in to 3% for Khasi, 6% for Hajmohammadi and 7 % for poplar experimental samples. Finally the significant correlation coefficients were found between the static and the dynamic modulus of elasticity for both two kinds of date palm.
Management and Economics wood
Mysam Khalilian Shalamzari; Mahammad ali Sadat nia; Hamid reza Pirayesh
Abstract
The aim of this study was to investigate the effects of natural weathering induced by critical climate conditions on quality of sugarcane bagasse lignocellulosic material in Pars factory. The experimental samples selected from fresh and also stored bagasse for durations of 6 months, 1, 2 and 5 years, ...
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The aim of this study was to investigate the effects of natural weathering induced by critical climate conditions on quality of sugarcane bagasse lignocellulosic material in Pars factory. The experimental samples selected from fresh and also stored bagasse for durations of 6 months, 1, 2 and 5 years, were used. The mechanical and the chemical properties as well the color variations were measured on taken samples. The results showed that the long storage durations of bagasse significantly decreased the quality of row materials observed in hand sheet tensile and fold strengths. The results illustrated that the amount of Lignin and extractives increased (44 % in lignin and 32% in extractives amount respectively) and also decrease in amount of cellulose and hemicellulose was found (10% for cellulose and 43% for hemicellulose) during 5 years storage in yard. According to the results, there was an obvious difference in L and a color index of 5 years old bagasse in comparing with those of fresh bagasse. Finally it can be drawn that the use of discorded and weathered bagasse could cause the loss in the final products quality which means more chemical treatment for bleaching and more using long fiber in paper making process.
