Reza Oladi; Hamidreza Yavarian; MohammadHossein Sadeghzadeh Hallaj; Kambiz Pourtahmasi
Abstract
Tamarisk is a drought-resistant tree that is important environmentally and has industrial applications in some countries. The aim of this study was to compare different populations of this species in terms of diameter growth rate (growth ring width), physiological adaptability (vascular characteristics) ...
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Tamarisk is a drought-resistant tree that is important environmentally and has industrial applications in some countries. The aim of this study was to compare different populations of this species in terms of diameter growth rate (growth ring width), physiological adaptability (vascular characteristics) and wood application characteristics (fiber biometry). The study was conducted on ten-year-old saplings of six tamarisk populations that had previously been collected from different regions of Iran (Qom, Kashan, Khash, Zabol, Garmsar and Yazd) and planted in Garmsar. The results showed that Garmsar population has the largest diameter and radial growth among populations. This population chose the best strategy for adapting to cold and dry climates by keeping the vessels small and significantly increase their number, instead. This has been the reason for its better radial growth. Although the biometric properties of fibers and paper ratios showed significant statistical differences between populations, these differences were not so great as to have a significant impact on the quality of the resulting paper in practice. Therefore, although the population of Yazd was of better quality in terms of paper parameters, the selection of the best population for industry should not be only based on fiber biometry and other features such as production volume, adaptability to habitat and survival rate of seedlings should be given more importance. The positive correlation between the width of the growth rings and the length of the fibers from the perspective of wood cultivation is very favorable because the treatments that increase the growth rate will also improve the fiber properties. In general, it can be concluded that Garmsar population is the best option for planting and cultivating tamarisk in terms of adaptability to environment and wood farming.
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.
Mechanical conversion of wood and wooden fittings
Mosayeb Dalvand; Ghanbar Ebrahimi; Kambiz Pourtahmasi
Abstract
In this study effect of staple length (penetration length) and its number in connection, on withdrawal capacity in face and edge of laminated veneer lumber (LVL) out of poplar was investigated. In this investigation, the staple with 3 and 4 cm penetration length and staple with 3, 4 and 5 cm penetration ...
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In this study effect of staple length (penetration length) and its number in connection, on withdrawal capacity in face and edge of laminated veneer lumber (LVL) out of poplar was investigated. In this investigation, the staple with 3 and 4 cm penetration length and staple with 3, 4 and 5 cm penetration length for withdrawal capacity in face and edge were used respectively. Number of staples at 4 levels (2, 3, 4 and 5) were chosen as a variable. Results have shown that withdrawal capacity in face significantly increases with increase of penetration length. Withdrawal capacity in edge increases drastically with increase of penetration length from 3 to 4 cm, but increase in penetration length from 4 to 5 cm had no significant effect. Withdrawal strength capacity in face has increased with increase of staples number. But, increase of staple number had no significant effect on withdrawal strength capacity in edge. Maximum withdrawal capacity was observed in joints fabricated with penetration length of staple 4 cm and number of 5 staples in face and minimum those were observed with penetration length 3 cm and number of 2 staples in edge.
Management and Economics wood
Reza Oladi; Saeideh Nasiriani; Afshin Danekar
Abstract
From a long time ago, researchers in the fields of wood science, dendroclimatology and tree physiology were interested in variation of tree-ring width and vessel features within a tree. However, mutual relationship and interplay between these anatomical features were less studied. In this regard, the ...
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From a long time ago, researchers in the fields of wood science, dendroclimatology and tree physiology were interested in variation of tree-ring width and vessel features within a tree. However, mutual relationship and interplay between these anatomical features were less studied. In this regard, the main question is whether the pattern of adjustment in wood anatomical traits (tree-ring width and vessel features) is similar in all hardwoods and in every site? Or may the same species chose different strategies in different sites? To answer these questions, two growing sites of black alder (Alnus glutinosa) with completely different micro-climates (dry and brackish) were selected near Astara city. In each site, a few trees were selected, cut or cored. After preliminary treatments, wood cross sections were prepared from the bark to the pith of each tree. These sections were scanned and by using an image analysis software, tree-ring width (TRW), average vessel lumen area (AVLA), number of vessel in the unite of an area (VF), and the porosity (Porosity) of a tree ring were measured in the last 20 annual rings of each tree. To study the inter-relations between variables at each site, they were analyzed using different statistical tests. The results showed that the inter- and mutual-relations between tree-ring width and vessel features were similar in tow studied sites. In brief, it can be concluded that regardless of site and climatic condition, in alder trees, wider tree rings leads to fewer vessels and these two anatomical traits are controlled by the same component but AVLA is affected by a different component and is not associated with the tree-ring width.
Mohammad ali Sadat nia; Ali akbar Enayati; Loeic Brancheriau; Kambiz Pourtahmasi; Farhang Honarparvar
Abstract
The acoustic behavior of reaction and normal woods, phase velocity, group velocity and attenuation coefficients in the main directions for two wood species (Populus deltoids & Picea abies), were measured and compared. The results did not show any significant difference between phase velocities of ...
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The acoustic behavior of reaction and normal woods, phase velocity, group velocity and attenuation coefficients in the main directions for two wood species (Populus deltoids & Picea abies), were measured and compared. The results did not show any significant difference between phase velocities of normal and tension wood at the same ring in poplar wood. But in compression wood from spruce, phase velocity in longitudinal direction was lower; while in transverse direction was higher compared to normal wood. Group velocity as an index of speed of wave energy in compression wood also was less than that in normal wood. In radial and tangential directions, there was no significant difference between group velocity of compression and normal woods of spruce. In poplar species, in all main directions, the measured group velocities, both for tension and normal woods were identical. The result also showed that the attenuation coefficients in reaction wood of two wood species (poplar and spruce) were less than those of normal wood in all directions. In compression and tension woods, a high correlation was observed between acoustic radiation and wood density.
Pulp and paper
Yahya Hamzeh; Mohammad hassan Ekhtera; Ali Abdolkhani; Sohila Ezadyar; Kambiz Pourtahmasi
Abstract
In this study the effects of several parameters on the sizing efficiency of test liner using poly aluminum chloride and rosin under neutral condition in reverse and premixing sizing processes were investigated. The results indicated that the individual effects of poly aluminum chloride amount, rosin ...
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In this study the effects of several parameters on the sizing efficiency of test liner using poly aluminum chloride and rosin under neutral condition in reverse and premixing sizing processes were investigated. The results indicated that the individual effects of poly aluminum chloride amount, rosin amount, interval time as well as interaction effect of poly aluminum chloride -rosin amounts in both sizing processes affect significantly sizing performance. The most important variable was the poly aluminum chloride amount. The effect of poly aluminum chloride amount on the sizing efficiency depended on the properties of fiber surfaces. This study showed that the interval time on the sizing efficiency is significant. To obtain an identical degree of sizing, it is possible decrease the amount of poly aluminum chloride and rosin amounts by increasing the interval time. In addition, the results confirmed two different mechanisms involved in the premixing sizing process.
