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.
Chemistry of wood
Mohammad Reza Sabzehparvar; Ahmad Jahan latibari; Shademan Pourmousa
Abstract
Background and Objectives: Plant extractives show unique properties. They impart colors and change the color of wood and generates attractive appearance. Since early days, societies have been utilizing plant extractives in industrial, medical and even as fungicides and biocides. In early times ...
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Background and Objectives: Plant extractives show unique properties. They impart colors and change the color of wood and generates attractive appearance. Since early days, societies have been utilizing plant extractives in industrial, medical and even as fungicides and biocides. In early times this application was based on the professional experiences, but as the sciences were advanced, then the technical and experimental identification and utilization was employed. In general, people look at walnut tree wood and fruit as its economic values. However, scientific research has proved the values of walnut tree extractives. In this study the chemical composition of walnut tree extractives and its variation in two periods of spring and summer as well as the impact of the drying on quantity and quality of the extractive components are investigated.Methodology: Walnut tree leaves from a selected location of an old walnut tree (100 years old) in mountain region of Karaj were collected in spring and summer. One part of the samples was air dried and another portion was used at green moisture condition. Totally four samples were obtained. Ethanol-acetone extraction was according to Tappi T204-05 procedure. The extractive was identified using GC-MASS spectroscopy and the chemical components in the extractives were identified and tabulated. Results: The results revealed that the dried leaves contain fewer chemical compounds compared to green samples which can be an indication that some of the compounds in green sample are volatile and vaporize upon drying. Furthermore, the extractives chemical composition and content varies between spring and summer samples. The major chemical compounds identified were 2-methylneptaline, tri-decan, tetradecan, 2,3-dimethyl naptaline and methylcyclobenzen.Conclusion: The results indicated the seasonal variation of walnut tree extractives. These is also considerable variation in wet and dry samples which can be attributed to the presence of volatile compounds. The odor of walnut leaves is the consequence of existence of such volatile extractives. The absence of some of the compounds in summer samples indicate the seasonal changes of the extractives.
Pulp and paper
Maryam Alipoor; Ghasem Asadpur Atouei; Seaid Majid Zabihzadeh; Zohreh Ghazvini
Abstract
With considering that in chemical-mechanical pulp (CMP) production process , the wood chips washing pre-treatment is important , so this research was conducted to investigate the effect of pre-treatment washing of populous deltoids wood chips on CMP Optical(brightness and opacity) and Strength(tensile ...
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With considering that in chemical-mechanical pulp (CMP) production process , the wood chips washing pre-treatment is important , so this research was conducted to investigate the effect of pre-treatment washing of populous deltoids wood chips on CMP Optical(brightness and opacity) and Strength(tensile and burst indexes) properties. Pre-treatment was accomplished with pure hot water and alkaline solutions (NaOH) at three levels of 0.5, 2 and 3.5 percent too. Pre-treated populous deltoids wood chips and control (chips without washing) were converted to pulp by CMP process. The results of this research indicated that the pretreatment of populous deltoids wood chips with hot water and also alkaline solutions caused wood chips mass and using of these treated chips for pulping caused pulp yield and brightness increscent, pulp strength reduction and also energy consumption increscent. . Removing of some part of chips hemicellulos have negative effect on the pulp refinability and cause pulp strength reduction.
Management and Economics wood
milad tajik; ramin vaysi; majid kiaei
Abstract
This research was carried out to identification and comparison of organically chemical component in the wood / bark extractives Eucalyptus camaldulensis. Three healthy trees were cut down from Nowshahr forest and samples were converted into the wood flour. The extractives was prepared with acetone solvent ...
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This research was carried out to identification and comparison of organically chemical component in the wood / bark extractives Eucalyptus camaldulensis. Three healthy trees were cut down from Nowshahr forest and samples were converted into the wood flour. The extractives was prepared with acetone solvent according to TAPPI standard, then transfer to the ballon and then the BSTFA catalyst was added and transfer to the GC / MS injections. Identification of components was done according to the retention time curve, calculation of Kovats correlation and Adams table. Out of 13 components in the bark of Eucalyptus and 18 components in that wood, 2 constituents such as Bis (2 - ethyl hexyl) phthalate and hexadecanoic acid was detected as the same. The most important of chemical component in the bark is (2 _ ethyl hexyl) phthalate (98.72 %). 2 - Pentanone (57.41 %) was important component in the eucalyptus wood .
Management and Economics wood
Aliakbar Aenayati; Hamid Hatefnia
Abstract
Microbiological degradation of wood and wood products is one of the most important of disadvantage which reduce its useful life. There are various methods to increase the natural durability of wood and wood products and most of them using chemical reagents. In the past, the thermal ...
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Microbiological degradation of wood and wood products is one of the most important of disadvantage which reduce its useful life. There are various methods to increase the natural durability of wood and wood products and most of them using chemical reagents. In the past, the thermal modification has been used as a ecofriendly method in many times. In this research the effects of steam pretreatment on the fungal durability of particleboard were studied. Steam pre-treatment was applied on the poplar wood particles using a stainless steel reactor at four temperature levels (155, 165, 175 and 185 ºc) and three retention times (15, 30 and 45 min). The amount of hemicelluloses, acetone extractives of wood particles as well as EMC and Mass loss of test panels were measured.The results indicated that the steam pretreatment significantly decreased the amount of hemicelluloses of wood particles, EMC and mass loss of test samples where as the amount of extractives of wood particles increased.According to the results, the variation of Mass loss of particleboard test samples showed a significant correlation to the variation of EMC of test samples, hemicelluloses and extractives amount of wood particles when the wood particles thermally pre-treated at 165ºC for 30 minutes
Chemical conversion
Seyyed Peyman Hashemi Beygzadmahalleh; Seyyed Pedram Hashemi Beygzadmahalleh; Asghar Tabei
Abstract
Tobacco (Nicotianan tabacum) and an old industrial plant in the north, Iran to supply tobacco leaf to produce significant amounts of stem tobacco cultivation and the annual production is in the north of the country. In this research stems of tobacco variety Coker 347 randomly Gilan district, city of ...
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Tobacco (Nicotianan tabacum) and an old industrial plant in the north, Iran to supply tobacco leaf to produce significant amounts of stem tobacco cultivation and the annual production is in the north of the country. In this research stems of tobacco variety Coker 347 randomly Gilan district, city of Astara was prepared according to the TAPPI standard test, wood flour were prepared and extractives were determined. The results showed that the mean shoot extractive tobacco varieties Coker 347 (10.41 percent). The extractive solvent toluene - ethanol volume ratio (2 : 1) of milled wood was extracted. Extractive made into a glass vial and transferred to the BSTFA reagent was added. Samples for one hour at room temperature and 70 ° C water bath and then by (GC / MS) were analyzed. Atotal of 11 chemical compounds in tobacco stem wood extractives variety Coker 347 were identified with different percentages of tobacco stem wood Coker 347 varieties exist. These compounds include, P- Prydyn , 1 – tri methyl Saylyl , 1,2 - benzene di- carboxyl acid , alpha - D - Golokopyranoz , 11, 8 – di methyl - 13 - (4 - aksu -1 - methyl ) , tri Floyver methyl isopropyl sulfide are the highest values.
Saeideh Sharifi; Jalil Roshanasan; Sayed zya aldin Hosseini
Abstract
Okaliptus is a fast –growing and light – liking tree that its trunk is smooth and is shelled spontaneously. n a short time its diameter and height increase.for its fast growing. So that turing it into things is difficult Fiber s traction is high and deksity is 0.55 to 0.58 a square centimeter. ...
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Okaliptus is a fast –growing and light – liking tree that its trunk is smooth and is shelled spontaneously. n a short time its diameter and height increase.for its fast growing. So that turing it into things is difficult Fiber s traction is high and deksity is 0.55 to 0.58 a square centimeter. The samples were prepared from the branches and trunk of Ocalyptus Kameldolensis with the average old of three years, from Jiroft region in Kerman province. After ordaining the age and having samples from the same age , some discs were prepared for cutting to measure fibers.Making ready and suspension of fibers were done in Fraklin method .Measuring amaout of lignin was done to standard no: T222- om – 88 and TAPPI guide directions . Measuring cellulose was done according to Nitric Acid method and due to standard No : T264 – om – 88 , and TAPPI guide directions. Due to results the length of trunk fibers was 811.36 and branches was 845.68 micro meters.Diameter of trunk fibers is 19.3 but branches 15.64, these amounts don,t have a meaningful differnce the level of 5&1 percent . Diameter of the carity of rrunk fibers was 10.71, but branches 3.44 at the level of 5&1 percent , they don,t have a meaningful difference. The amount of extracted articles of trunk is 4/5 but branches 2.3 percent ,and amount of lignin in trunk was 35.66 but in the branch 24.66, and amount of cellulose in trunk was 55.66 and the branch 46.81 percent which at the level of 5&1 percent have a meaningful difference . The amount of Ashes from trunk was 0.73 but from the branch 0.88 that at the level of 5&1 percent , don,t have a meaningful defference.
Sayed mahmood Kazemi; Aliakbar Enayati; Heshmatalah Rahymian
Abstract
The durability of following five wood species: Zelkova carpinifolia, Ulmus glabra, Pterocarya fraxinifolia, Carpinus betulus and Acer laetum were studied. Wood blocks exposed to Trametes versicolor(a white rot fungus) under laboratory conditions according to DIN52176 standard. After 16 weeks incubation ...
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The durability of following five wood species: Zelkova carpinifolia, Ulmus glabra, Pterocarya fraxinifolia, Carpinus betulus and Acer laetum were studied. Wood blocks exposed to Trametes versicolor(a white rot fungus) under laboratory conditions according to DIN52176 standard. After 16 weeks incubation the heart wood of Z. carpinifolia showed 2.19% reduction in weight loss, while U glabra with 41.69%, C. betulus with 45.64%, A. laetum with 53.03% and P. Fraxinifolia with 43.08% weight losses were very decayed. For finding relationship between amount of wood decay and wood extractives a regression was carried out. The percentages of extractive materials by using T20403 standard were 13.84% in Z. carpinifolia, 4.51% in U. glabra, 2.74% in C. betulus, 3.88% in A. laetum, and 4.11% in P. fraxinifolia. Finally there was a negative correlation between rate of decay and amount of wood there was expect P. fraxinifolia. for all wood species extractives.
Chemical conversion
Saeed Mahdavi; Abdolrahman Hosseinzadeh; Abbas Fakhryan roghani; masoudreza habibi
Abstract
In order to evaluate reed as a raw material for wood & paper industries, three main regions of Iran consist of south, North and East were selected for this study. Phragmites australis is dominant species in these regions and this study concentrated on it as well.Chemical components and biometry of ...
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In order to evaluate reed as a raw material for wood & paper industries, three main regions of Iran consist of south, North and East were selected for this study. Phragmites australis is dominant species in these regions and this study concentrated on it as well.Chemical components and biometry of fibers were determined with four and thirty replications respectively. Statistical analysis showed that there were no significant differences among three regions in fiber length and lumen diameter but reversely fiber width and cell wall thickness showed significant differences. The highest fiber length mean was 1.39mm. For North (Anzali) Coefficients of papermaking of fibers also were calculated for each region. Biometerical fiber results, showed that P. australis has good fiber compare to the Iranians hardwoods as papermaking.The results also showed that there are significant differences between regions and subregions at %5 level. North had the highest and lowest cellulose and lignin contents respectively. These results also proved that P.australis is one of the best Iranians' raw materials as cellulose and lignin contents between the others.
