Chemical conversion
Zahra Daeepour; amir lashgari; Mehran Roohnia; Ahmad Jahan latibari; Vahid Safdari
Abstract
Background and objectives: Nowadays, the importance of treatments such as water washing and ethanol-acetone washing to improve the acoustic properties of wood has been noticed by the makers of musical instruments. Wood extractives are in the list of those materials that often do not have a construction ...
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Background and objectives: Nowadays, the importance of treatments such as water washing and ethanol-acetone washing to improve the acoustic properties of wood has been noticed by the makers of musical instruments. Wood extractives are in the list of those materials that often do not have a construction role, and their purposeful and correct evacuation can lighten the wood without reducing the stiffness. Carrying out pre-treatments such as fermentation with bread yeast (before water washing and ethanol-acetone washing processes) can lead to the extraction of more extractable substances from wood. In this study, the effect of water washing and ethanol-acetone washing treatments as well as fermentation pre-treatment on the acoustic properties of Ash wood (Fraxinus excelsior) has been investigated.Methodology: Ash wood species (Fraxinus excelsior) was prepared from the wood of a commercial timber and 38 small radial beams with nominal dimensions of 150×12×2 mm (longitudinal×radial×tangential) were extracted from the hardwood. After reaching the equilibrium humidity of 12% in air-conditioned conditions, the selected samples were subjected to the forced vibration test in the free-free beam in order to measure the basic physical and acoustic characteristics. After that, the initial tests were randomly divided into two groups of 19 tests. The first group without pretreatment and the second group with fermentation pretreatment were placed in the process of removing the extractives by water and then by ethanol-acetone mixture. After each step of water washing and removing the extractive substances soluble in ethanol-acetone mixture, the forced vibration test in the free-free beam was performed on the samples and the acoustic properties of the samples were measured.Results: Water washing without pretreatment with bread yeast caused a slight decrease and with pretreatment, it caused a significant decrease in density values (respectively: 1.75 and 7.39%). While the process of removing extractives (with and without pretreatment) by ethanol-acetone mixture caused a significant decrease in density values (Respectively: 2.27 and 8.71%). The modulus of elasticity values showed a significant decrease due to water washing without pretreatment and with pretreatment. (Respectively: 11.37 and 16.47%). The process of removing the extractives by ethanol-acetone mixture also resulted in a significant decrease in the modulus of elasticity values in untreated and pretreated samples (Respectively: 13.87 and 20.93%). Water washing without pre-treatment with bread yeast and with pre-treatment has caused a significant decrease in the values of damping factor, among which the pre-treated samples had a greater percentage of drop in the values of damping factor (Respectively: 13/87 and 20.93%). The process of removing the extractive materials by ethanol-acetone mixture as washing has caused a significant decrease in the damping factor values, which among the pre-treated samples showed a greater percentage drop in the values resulting from this property (Respectively: 3.03 and 18.01%). In this factor, the process of removing the extractive substances soluble in ethanol-acetone mixture (with and without pretreatment) has resulted in a greater drop in damping values (respectively: 6.67% and 20.85%). Acoustic conversion efficiency due to water washing process without pretreatment with baker's yeast caused a slight increase, while pretreatment caused a significant increase in acoustic conversion efficiency values (Respectively: 0.44 and 25.24%). The process of removing extractive materials by ethanol-acetone mixture also caused a significant increase in the acoustic conversion efficiency values, which among the pre-treated samples showed a higher growth percentage in the values of this characteristic (Respectively: 3.41 and 28.90%). Both water washing methods and ethanol-acetone mixture washing were effective in improving the physical (density) and acoustic properties (modulus-elasticity, damping and acoustic conversion efficiency). Meanwhile, the effect of ethanol-acetone mixture washing was more than the effect of water washing. Fermentation pretreatment with bread yeast improved the performance of water washing and ethanol-acetone mixture washing treatments.
Physics and anatomy
Vahid Safdari
Abstract
The suitability of wood and noon-wood species for using in pulp and paper industry can be predicted by their morphological and chemical characteristics. In these research morphological and chemical properties of four spices of Ulmacea family, Ulmus glabrar, Ulmus compestris, Zelkova carpinifolia and ...
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The suitability of wood and noon-wood species for using in pulp and paper industry can be predicted by their morphological and chemical characteristics. In these research morphological and chemical properties of four spices of Ulmacea family, Ulmus glabrar, Ulmus compestris, Zelkova carpinifolia and Celtis australis have been compared. From each species three cross section, 5 cm thickness has been selected. Wood slivers of tree zones: near to pith, middle part and near to bark wood have been macerated in mixture of acetic acid and hydrogen peroxide at 60°C for 48 hours. Biometric coefficients of fibers in three zone and four species have been measured and analyzed by factorial, complete randomized block design. Result showed that, Zelkova carpinifolia has least lignin, ash and extractives and highest cellulose. The fibers of, Zelkova carpinifoliahas has highest Slenderness ratio, Runkel ratio and hence in Ulmacea family is most suitable species for paper industry. Fiber length, wall thickness in near to bark zone in comparison to near to pith was higher significantly. Therefore it is predicted that the mechanical properties of pulp of this three zones are different
Physics and anatomy
Vahid Safdari
Abstract
Understanding of many wood technological features depends on anatomical characteristics which, unfortunately, researchers in Iran have not focused on recently. There are many trees and shrubs in the desert areas of Dasht-e Kavir and Dasht-e Lut with unstudied woody anatomical features. We studied one ...
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Understanding of many wood technological features depends on anatomical characteristics which, unfortunately, researchers in Iran have not focused on recently. There are many trees and shrubs in the desert areas of Dasht-e Kavir and Dasht-e Lut with unstudied woody anatomical features. We studied one of these species, Calligonum comosum (Polygonaceae). Three mature shrubs were selected and small cubic samples of woody stem and root were taken. Micro-sections were obtained with micro-tome and after dying with Astra-blue and Safranin the sections were mounted in Canada balsam. The results showed that many differences between roots and stems exist, such as distinct growth rings in the stems and indistinct rings in the roots, the presence of gums in the stems and absence in the roots, and lower ray width of the stems compared to the roots, inherent characteristics that have been reported by many other researchers. The most important difference between Calligonum comosum’s roots and stems is parenchyma-like fibers in the thin-walled roots which cannot be distinguished from axial parenchyma. The ground tissue of woody roots is parenchymatous cells full of starches, which probably can be related to the drought situation of deserts. The bark of Calligonum comosum has priderm and sclereid cells which make the bark stiff and hard. Also the result of particleboard of fabricated of Calligonum comosum’s wood showed that boards has at least technical characteristics of European Standard EN 312 and hence the silviculture of this species for stooping of erosion of soil and is suitable species for desertification and its wood can be used for producing of wood based panel.
Physics and Mechanical Wood
Ardlan Doreemam; Vahidreza Safdari; Abolfazl Kargarfard; Ajang Tajdini
Abstract
In this study, the effect of using waste of Alnus subcordata and Poplar wood in manufacturing particle board was investigated. The particle boards were produced by adding (0-25-50-75-100)% alder branches with poplar wood and two press temperatures 170°C and 180 °C. In total, 30 particleboards ...
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In this study, the effect of using waste of Alnus subcordata and Poplar wood in manufacturing particle board was investigated. The particle boards were produced by adding (0-25-50-75-100)% alder branches with poplar wood and two press temperatures 170°C and 180 °C. In total, 30 particleboards (10 treatments with 3 replications) were made and data was analyzed with complete randomized design. Results showed that particleboards which were made of 75% alder branches and 25% poplar wood with press temperature of 180 °C had the most flexural strength. In addition, this study manifests that the increase of alder branches up to 25% led to the enhancement of modulus of elasticity of particle boards while adding more than 25% caused in the decrease of the modulus of elasticity. The increase of alder branches would augment the internal bounding and thickness swelling of particleboards. Therefore, the particleboards of 100% alder branches had the best internal bonding. However, this research concluded that the press temperature would not any significant effects on mechanical and physical characteristics.
Physics and anatomy
vahidreza safdari; shadman Pourmosa
Abstract
The Avicennia tree genus was named in honor of Ibn Sina, a 10th century Persian philosopher and physician known more commonly as Avicenna. In this paper wood anatomical property of Avicennia marina (Acanthaceae) which is one of the most important species of Iranian Mangrove forest has been investigated. ...
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The Avicennia tree genus was named in honor of Ibn Sina, a 10th century Persian philosopher and physician known more commonly as Avicenna. In this paper wood anatomical property of Avicennia marina (Acanthaceae) which is one of the most important species of Iranian Mangrove forest has been investigated. Wood samples were taken from trunk of three adult trees, and and micro -sectioned and dyed by Astrablue and Safranin O and finally mounted by Canada balsam. Also Wood chips (match size) were placed in equal parts of glacial acetic acid and hydrogen peroxide and were put in the oven at 60°C for 48 hours, then counted and stained on microscope slides. The presence of concentric included phloem which is surrounded by lignified conjunctive parenchyma (axial parenchyma) and scleroid bands are the most important anatomical characteristics of Avicenna marina. The variability of anatomical characteristics of Avicennia marina in different references can be attributed to grwoing site condition (altitude and latitude).
Vahid Safdari; Seyyed Peyman Hashemi Beygzadmahalleh; Asghar Tabei; Seyyed Khalil Hosseinihashemi
Abstract
Tobacco (Nicotiana tabacum) is one of the non-wood species and its stalks are the main crop after harvesting which can be used in composite board and paper industry. For better use of this non-wood fibrous raw material, the evaluation of anatomical, morphological and chemical components are necessary. ...
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Tobacco (Nicotiana tabacum) is one of the non-wood species and its stalks are the main crop after harvesting which can be used in composite board and paper industry. For better use of this non-wood fibrous raw material, the evaluation of anatomical, morphological and chemical components are necessary. Tobacco stalks "Coker"cultivar 347 which is widely planted in Gilan province of Iran were randomly sampled. Anatomical properties (cross, tangential and radial sections) and morphological properties (fiber length, fiber diameter, and cell wall thickness) were measured and the indices and ratio of the fibers including: slenderness index, runkel index, flexibility ratio in three heights of stem (5%, 50% and 75%) were calculated. The Chemical components including: Cellulose, lignin, ash, alpha cellulose and hemicellulose of stem with bark and without bark were recorded according to related standards and the results were ststistically analyzed. Results showed that the chemical components of the tobacco stalk were desirable but the index of L/D of fibers were lower than many non-woods and hardwoods. Therefore, it is assumed that the paper produced from tobacco stalks do have suitable tear strength. The runkel index (2 cell wall thickness / fiber diameter) is close to hardwoods and many non-woods, Therefore, it is presumed that paper have appropriate tensile, burst and folding strength. It is predicted that tobacco stalks combined with softwoods with long fibers can produce good quality paper.
Vahid Safdari
Abstract
One of the important families of woody species of Irano-Torani region is Chenpodiaceae which comprises of different woody genus and species and Seidlitzia rosmarinus an specie with vast geographical distribution belongs to this family. Irrespective of its vast spread, the anatomical and other properties ...
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One of the important families of woody species of Irano-Torani region is Chenpodiaceae which comprises of different woody genus and species and Seidlitzia rosmarinus an specie with vast geographical distribution belongs to this family. Irrespective of its vast spread, the anatomical and other properties the specie has not been studied. In order to study the anatomical properties, 6 sound shrubs of Seidlitzia rosmarinus in Ardakan (Yazd, Iran) were harvested and the physical, chemical and anatomical properties of the wood were determined. The anatomical features were determined using light microscope and scanning electron imaging (SEM). Results showed that growth rings boundaries are indistinct; Intrexylary phloem (included phloem) is concentric. Vessels are short (100 µm) and gum–like deposit are present and inter-vessel pits are very tiny. The fiber length is short (334 µm) and fiber wall thickness (2d= 8.4 µm) in comparison to lumen (7.5 µm) is thick. Seidlitzia rosmarinus is anatomically and biometrically similar to Atriplex. The density in normal condition is 0.92 gr/cm3 which categorized the wood as heavy wood and its longitudinal shrinkage and ash content were measured as 5% and 5.5%) respectively.
Mysam Abdolali sarbandi; Vahid Safdari; Sayed javad Sepidedam; Esmaeil Ganjyan
Abstract
In this research, the properties of cement fiberboard produced using different contents of nano-silica and bleached bagasse fibers were evaluated. Different ratios of bagasse fibers, cement and nano-silica were blended using an electrical blender. The mixture was then poured into a mould (15x18x18 ...
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In this research, the properties of cement fiberboard produced using different contents of nano-silica and bleached bagasse fibers were evaluated. Different ratios of bagasse fibers, cement and nano-silica were blended using an electrical blender. The mixture was then poured into a mould (15x18x18 cm dimension). The produced mould samples were matured for 14 days at room temperature and high moisture content (100%) and after maturing, the bending strength and physical properties of boards were measured. Results showed that both materials (naosilica and bagasse fibers) changed the bending and physical properties of the final boards. The bending strength of samples increased with the increase in nano-silica up to 1% and exceeding 1% decreased this property. It is because high content of silica (more than 1%) results in aggregate of nano-silica and cement and micro cracks occurred in samples. Also the increase in bagasse fiber up to 4% increased of bending strength of boards and more bagasse fibers decreased the bending strength. It is because high bagasse fibers cannot distribute in the cement matrix and fiber bundles reduced the bending strength. However, as the nano-silica and bagasse fibers content increase, the water and moisture absorption as well as thickness swelling increases, whereas density decreases.
