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Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Title: 
Author(s): 

Issue Info: 
  • Year: 

    0
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    -
Measures: 
  • Citations: 

    0
  • Views: 

    1005
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Title: 
Author(s): 

Issue Info: 
  • Year: 

    0
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    -
Measures: 
  • Citations: 

    0
  • Views: 

    1266
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Title: 
Author(s): 

Issue Info: 
  • Year: 

    0
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    -
Measures: 
  • Citations: 

    0
  • Views: 

    992
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Title: 
Author(s): 

Issue Info: 
  • Year: 

    0
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    -
Measures: 
  • Citations: 

    0
  • Views: 

    1027
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1027

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Title: 
Author(s): 

Issue Info: 
  • Year: 

    0
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    -
Measures: 
  • Citations: 

    0
  • Views: 

    728
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    1-22
Measures: 
  • Citations: 

    0
  • Views: 

    1029
  • Downloads: 

    0
Abstract: 

Background and objectives: Ribes khorasanicum is a deciduous woody shrub form and is one of the most valuable species belongs to the monogenus family of Grossulariaceae. Ribes is a genus has about 150 species of flowering plants native throughout the temperate regions of the Northern Hemisphere. Because of the nonnormative utilization, the utility of fruits, high palatability, livestock grazing, restricted ecological range, high ecological demands and sexual reproduction difficulties (mainly regenerates by the vegetative method by rhizome) facing risk of extinction. One of the possible methods of protection of the endangered taxon is multiplying and conservation of plants with help in vitro cultures.Materials and methods: Axillary and apical buds of the branches obtained from endemic plants in Hezarmasjed Mountains were used as initial explants. In this research effect of two cytokinins, BAP and Kinetin in presence or absence of auxin on proliferation coefficient and growth of multiplied shoots were investigated. The concentrations (0, 0.5, 1, 3 and 5) mg/l of each of cytokinins in the presence or absence of 0.05 mg IBA were studied. Furthermore, effect of nutrient concentration and sucrose concentration of cultural media, IBA and BAP hormones on rooting Percent and plantlet root length was investigated. Used treatment for root induction investigations was the concentrations of (0, 0.1, 0.25, 0.5, 1, 2 and 5) mg/l of IBA hormone in presence or absence of 0.1 mg/l of BAP hormone in MS and MS/2 media.Results: Results showed that, BAP hormone has the better shoot multiplication index than kinetin, considering the high rate of proliferation and higher shoots, the most suitable culture media for multiplication was MS media supplemented by 1 mg/l BAP. According to the treatments evaluated, and the average percentage of rooting and root length of plant lets, for root induction the best media was, modified MS media which sucrose concentration reduced to 15 g/l, and supplemented with0.5 to 2 mg/l of IBA. Addition of 0.1 mg per liter BAP decreased the percentage of rooting and root length. The longest root of plantlets was obtained from the modified MS media supplemented with 2mg/l IBA. Plantlets were successfully transferred from tissue culture vessels to ex vitro conditions with about 86 percent survival.Conclusion: According to high multiplication index and successful acclimatization of tissue cultured plantlets, the tissue culture can be used as an alternative with seeds and cuttings propagation methods to maintain and expand this valuable herbal shrub.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    23-43
Measures: 
  • Citations: 

    0
  • Views: 

    1243
  • Downloads: 

    0
Abstract: 

Background and objectives: One of the best strategies to identify suitable tree species effect on the circulation of nutrients in the soil and plants as well as the carbon cycle is soil quality and quantity study of soil nutrients. To achieve this goal, three types of poplar cover and pine forests cover in the safrabsteh region of Gilan were selected.Materials and methods: Forest's cover was actually studied together. Each type of forest cover was divided into three parts while each part was as a repeater. With each repeat, a profile was dug to a depth of one meter and soil samples were taken from various depths. Some chemical properties of the soil and the amount of nutrients absorbable (N, P, K, Ca, Mg) were measured in triplicate under each cover.Results: The results showed that the amounts of organic carbon, nitrogen and phosphorous coating on the cover of poplar P. deltoides 77.51 was the highest amount but the potassium in the control sample was greater than the size of the whole three. Low intake of essential elements, especially iron and copper in soil under poplar coverage P. deltoides 77.51 and p. caspica had the highest and lowest amount, respectively. The amount of carbon sequestration in soil in the coverage of Populus deltoides M.77.5, was 71.85 tons per hectare, which was more than any other coverage. Except for for the calcium and magnesium the rest of the elements from the surface to the depth had a significant decrease that these differences in some elements, such as potassium were low and in organic carbon was high.Conclusion: On the other hand, the amount of organic material in soil nitrogen and phosphorus cause increased coverage. Increase the amount of phosphorus in iron and copper can be reduced. Coverage attracted. Covered by deciduous conifers Taxodium distichum compared with covered fir nutrients and organic carbon stored in the soil is considerably more than other cases in the soil, even more than the other cases. Chemical properties and quality of the nutrient in the coverages showed that forest plantations with Populus deltoides M.77.5 was more efficient than Populus euramericana I-214

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    45-68
Measures: 
  • Citations: 

    0
  • Views: 

    733
  • Downloads: 

    0
Abstract: 

Background and objectives: In order to investigate the spatial pattern of forest cover changes in the county of Malekshahi in Ilam province during 1976 to 2014, logistic regression modeling techniques were used. Logistic regression model is able to well determine the relationship between forest cover change (dependent variable) and its influencing factors (independent variables).Materials and methods: To survey the forest cover changes, the images of Landsat 1 satellite from MSS sensor relating to 1976 and the images of Landsat 8 from OLI sensor relating to 2014 were processed and classified. The surveyed images were classified into two classes of forest and non forest. To investigate the causes of degradation, forest cover changes map with physiographic and human spatial variables were integrated into model.Results: The evaluation of the regression model with ROC (0.8210) and Pseudo-R2 (0.2514) indices indicated the ability of the model to describe the changes and to identify the areas prone to change. The results showed that approximately 26491.9 ha of forest areas was reduced during 38 years.Conclusion: According to the results of modeling, it was found that altitude, soil depth, distance along the forest edge, aspect, slope, distance to drainage, population distribution, distance to the road and village had the greatest impact on the reducing of forest cover in the county of Malekshahi, respectively. The results of study can be considered in the future planning for the areas that are related to the vegetation/ land-use changes.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    69-87
Measures: 
  • Citations: 

    0
  • Views: 

    1398
  • Downloads: 

    0
Abstract: 

Background and objectives: Most of the soil physical, chemical, mineral and biological attributes are changed by forest fires. Fire is one of the most important factors of forest's destruction in Ilam region where considerable areas are annually exposed to fire. Depend on environmental conditions and also fire intensity, different effects will impose on ecological conditions within the environment.Whereas soil is considered as a base for forest’s growth and regeneration, study of fire effects on its properties takes an important place.Materials and methods: This research was carried out on the effects of fire on soil chemical properties in the three intervals of one, two and three years after a fire.For this purpose, three regional forest fires have been selected considering the similarity in topography and geology conditions. A control region was also selected near the study area (no fire).40 round sample plots of 100 m2 were taken to Bankool forests. Soil samples from a depth of 0-5 cm were collected from below and outside of the crown trees in four study area. Some chemical properties of soil samples were measured.Results: T-test results showed that there are significant differences between chemical variables under and outside crown in the first years of fire and four regions (p<0.05).Conclusion: pH and potassium level showed significant differences between under and outside the crown after two and three years of fire respectively (p<0.05).Duncan's test results indicate significant differences between chemical properties in time periods and under and outside of tree crown (p<0.05).

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

FARSHCHI V. | GHOFRANI M.

Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    89-106
Measures: 
  • Citations: 

    0
  • Views: 

    1168
  • Downloads: 

    0
Abstract: 

Background and objectives: The purpose of this study was to evaluate the factors affecting the market development for classic furniture.Materials and methods: For this purpose, parameters affecting the market development using furniture classic manufacturers Comments In the form of a standard questionnaire in 4 main categories: design, quality, price and marketing were defined. To investigate the validity of the questionnaire the Cronbach's alpha method and was used to assess validity of the questionnaire the validity content method. Ranking the main factors affecting the classic furniture market was performed in two ways Likert spectrum and relative importance ratio of each index.Results: The results showed that quality criteria has the first rank (3.701) and price criteria, marketing and design (3.348, 3.269, and 3.195) is in order of ranking next. Using the importance ratio of the index of price (0.2377) the first rank and indices marketing (0.2026), quality (0.1739) and design (0.0734) is in order of ranking next.Results: The quality and price indicators are more important than other indicators. So, with proper planning can be done by prioritizing effective step in taken the classical furniture market.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

RUDI H.R. | BORHANI A. | HAMZEH Y.

Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    107-123
Measures: 
  • Citations: 

    0
  • Views: 

    768
  • Downloads: 

    0
Abstract: 

Background and objectives: Nanotechnology methods like layer-by-layer technique have shown large potential for modifying the cellulose fibers characteristics and improving its quality. In this technique, cellulosic fibers and counter-ionic particles are placed in an interaction media. During the interaction, ionic particles are absorbed by fibers surface mainly via electrostatic absorption. There is rinsing step between consecutive layering in order to remove physically and loosely absorbed of particles on the fiber surface. Application of different steps of rinsing in this technique has made difficult for its practical use. Therefore, in current research, effect of using a modified layer-by-layer system (without rinsing stages) on enhancing the strength of papers made from recycled fibers has been examined.Materials and methods: The experiments were conducted to form 1 to 3 successive layers of cationic and anionic starches on recycled fibers prepared from an old corrugated container. For each layering stage, 500 ml pulp suspension (0.48 consistency) was mixed with starch solutions using a laboratory mixer at constant mixing of 750 rpm for 10 minutes. Then, the physical properties (thickness and apparent density) and strength characteristics (tensile index, burst index and TEA) of handsheets with 60±3 g/m2 basis weight prepared from treated and untreated fibers were compared.Results: The results have revealed that by treatment of recycled fibers with the modified system of layer-by-layer technique, unlike apparent density the thickness of paper decrease. Moreover, this system had a considerable impact on development of paper strengths. For example, by layering of three layers of ionic starches, tensile index of papers increased from 15.9 N.m/g to 47.29 N.m/g, burst index improved from 1.05 kPa.m2/g to 2.15 kPa.m2/g and tensile energy absorption increased from 2.42 J/m2 to 10.28 J/m2. Furthermore, SEM micrographs have shown a different appearance in treated fibers compared to the untreated fibers. It indicated an increase in gelatinization of treated fiber surface due to an increase in cationic starch absorption.Conclusions: Layering of cationic starch and anionic starch in the layer-by-layer modified system contributes to the increase electrostatic absorption of cationic starch on to the recycled fibers These phenomena with enhancing the bonds between fibers have resulted in improving the strengths of papers made from recycled fibers.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    119-220
Measures: 
  • Citations: 

    0
  • Views: 

    842
  • Downloads: 

    0
Abstract: 

Background and objectives: Some extractive compounds from wood, adhesives which are difficult to remove during pulp washing and cause adhesive residues on process equipment. In preparing pulp from hardwoods, these compounds are the source of numerous problems such as the formation of sticky materials, impurities remain in the paper pulp and paper break in paper machine. In addition, remain these compounds on paper caused problems such as creation dark spots and paper fibers stick on the cylinder surface, paper breaks and clogging with and felt. Also the extractives may react with chemical bleaching and produce changed and oxidized products. Changed extractives are causing pitch problem and have a negative impact on pulp brightness. In this study, the effect of hot water and alkali pretreatment on the bleach ability of hornbeam CMP pulp was studied.Methods and materials: Hornbeam wood chips prepared from Mazandaran wood and paper mill. In three levels of 0.5, 2 and 3.5 percent pretreated with hot water and alkali were done for aim of removing the extractives before pulping and then paper pulp prepared from control and pretreated wood chips with the same conditions and CMP process and bleached with hydrogen peroxide. Handmade paper produced from the resulting pulp and papers optical properties before and after bleaching and strength properties of produced papers before bleaching was examined.Results: The sample pre-treated with stable temperature and time, the mass loss during pretreated with hot water is less than pre-treated with alkali and in the alkali treatment, the mass loss increased with increasing alkali percent. In both pretreated cases, pretreated hornbeam chips pulp yield is more than the control sample. The refining rounds and energy consumption of paper pulp produced from alkali pretreated chips is more than pulp from wood chips pre-treated with hot water. The brightness of hot water and alkali pre-treated samples before and after bleaching increased to compare to the control sample. During alkali pre-treated, with increasing the percentage of alkaline, pre-treated samples also showed increase brightness. Before bleaching, opacity of pretreated sample with hot water had low increase and in general, no significant differences between the samples treated with hot water and control at the level of 5% was observed. The sample pretreated with stable temperature and time, the hornbeam tensile index increased. Pretreatment with alkali also showed that the increases in the tensile index. Burst index was increased by hot water and alkali pretreatments. Treatment of Samples with hot water and alkali also showed that and an increase in the tear index which was directly related to the percentage alkali.Conclusion: Pretreatment of Hornbeam wood chips with hot water and alkali caused to reduce wood chips mass and increase CMP wood pulp yield has been compared to the control samples. Brightness of pretreatment samples before and after bleaching increased than the control sample. Opacity in the samples pretreated with hot water increased and decreased during the treatment with alkaline solution. In those pre-treated with hot water and alkaline solution than the control sample, hornbeam paper pulp tear index increased but in burst index and tear strength, no difference significant has been observed.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    125-144
Measures: 
  • Citations: 

    0
  • Views: 

    893
  • Downloads: 

    0
Abstract: 

Background and objectives: Distance sampling methods are a group of commonly-used methods in estimation of quantitative characteristics of forest, although each method and related estimators have different efficiencies due to different factors (such as environmental conditions, stand density, and distribution of trees). Therefore, it seems necessary to know how these methods operate in open forests regarding to their importance and their role in estimation of quantitative characteristics with low cost and time. The objective of this study was efficiency assessment of 12 important distance sampling methods to obtain biometric characteristics of wild pistachio trees (density and canopy closure) in Zagros open stands. This study investigated the distance methods in two single- and multidistance groups. Moreover, it was aimed to select the appropriate estimator of each method and the efficiencies of these methods were compared in the same conditions.Materials and methods: A wild pistachio stand with low density (19.44 trees ha-1) was selected in Bane Research Site, Firoozabad, Fars province, south western Iran. Using a 100 m ´ 100 m mesh, 46 sample points were located within the boundary. Six single-distance and six multi-distance sampling methods were applied to estimate the characteristics. Root mean squared error was applied to evaluate the precision and accuracy criterion and comparing the means using onesample t-test were implemented to assess the accuracy of the results.Results: Using precision and accuracy criteria, the appropriate estimators were identified in nearest individual (Cottam et al.), nearest neighbor (Cottam and Curtis), and T-square (Byth) single-distance methods and point-centered quarter (Cottam and Curtis) multi-distance sampling method. To estimate density and canopy closure, nearest individual (Cottam et al.) and nearest neighbor (Cottam and Curtis) single-distance methods were the most efficient ones. Between multidistance sampling methods, Byth and Ripley (accuracy of 3.70% and p<0.05), joint (accuracy of 2.36% and p<0.05) and shared point (accuracy of 2.36% and p<0.05) methods were suitable for density and canopy closure estimation, respectively.Conclusion: In general, nearest individual and nearest neighbor single-distance methods were efficient enough to estimate the biometric characteristics of wild pistachio trees in the studied open stand precisely and accurately. The effect of sampling network and distribution of trees can be investigated in future studies.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

ASADZADEH F. | BARIN M.

Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    163-145
Measures: 
  • Citations: 

    0
  • Views: 

    735
  • Downloads: 

    0
Abstract: 

Background and objectives: The release of heavy metals into the environment, especially to the water resources is one of the main environmental concerns of the last few years. Copper is a common heavy metal in agricultural and industrial activities which significantly contributes to the pollution of surface and ground water resources. Since copper is a widely used material, its removal from aqueous solutions is a main challenge in water purification. Sawdust as a cost effective and locally available bio adsorbent, is a promising material for the removal of heavy metals especially copper from aqueous solutions. The aim of this study was to quantitative modeling of the effects of pH, copper concentration, sawdust dosage, and contact time on the copper removal from aqueous solutions.Materials and methods: In this study, the sawdust of Populus nigra with grain size of 250-600 mm, was used as a bio adsorbent for the removal of copper from synthetic aqueous solution. Sawdust sample was washed with distilled water and dried in the laboratory conditions. The sorption of copper on sawdust has been studied by using the batch technique. The central composite design was carried out with aqueous solution of copper containing various concentrations ranging from 1-25 mgl-1 The ranges of variation for the other variables including pH, sawdust dosage and contact time are 2-10, 5-25 gl-1, and 5-185 minutes, respectively. At the end of the each experiment, the equilibrium concentration of the copper was determined by atomic adsorption spectrometer and the removal percentage of the copper was calculated from the difference between the initial and equilibrium concentrations.Results: The results of the central composite design model demonstrated the high efficiency (R2=0.907 and RMSE=3.34%) of the predictive model for copper removal by sawdust. Pareto analysis of the central composite design model indicated that, among four variables, contact time, sawdust dosage, pH and initial copper concentration shave the highest effects on the copper removal respectively. Increasing of the pH at the range of 2 to 7, leads to the increase of the copper removal. The copper removal was also increased at high contact times and sawdust dosages. There was a negative relationship between the initial copper concentration and the removal percentage of the copper.Conclusion: It has been demonstrated that the Populus nigra sawdust can be considered as a suitable bio adsorbent of heavy metals. The efficiency of the copper removal by sawdust may be reach up to the 94 percent especially at low initial concentrations of the copper. Adjusting pH of the solution at the range of 6 to 7 leads to the high efficiency of copper removal by sawdust. Considering the low cost and availability of sawdust, it can be recommended as a bio adsorbent for purification of water resources from copper pollution.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    180-165
Measures: 
  • Citations: 

    0
  • Views: 

    779
  • Downloads: 

    0
Abstract: 

Background and objectives: Recently, there have been increasing public considerations about the visual quality of the road and roadside aesthetics. The visual quality of a road template mostly depends on landscape, marginal trees, road curves, state of the road surface, vegetation cover on the cut and fills slopes, and aesthetic along the roadside.Materials and methods: In this study, the selected forest road sections from district 3 of Shafarood forest, Guilan province were evaluated to assess the aesthetic of the forest road template. The number of 150 photos were taken from the four forest road templates with various date of establishment and evaluated by different people, considering forest road surface (Travel lane), cut-slope, fill-slope, and roadside (Shoulder and ditch). The quality of components in the photos had been evaluated by people and they had scored every one of them from 1to 5. Then the Average Aesthetic Value for each component was computed based on the total scores assigned to the photos. In order to estimate the final aesthetic value of the road templates, the value of Average Visual Quality was assigned to each forest road. The relationships between Average Aesthetic Value of road components and Average Visual Quality value were investigated for each research area by using a stepwise regression analysis. Friedman test was used in order to investigate the value of Average Visual Quality. The correlation among the Average Aesthetic Values (AAV) of road components was also examined for each research area by using Kendal test. Finally, the regression model was obtained for each forest road.Results: Results of average values showed that the highest quality was related to 1993 with 3.73 and the lowest quality was related to 2007 with 1.88. The results of Friedman test showed that there is a significant difference between of Average Visual Quality value in the different years (c2=63.25, d¦=3, a=0.000).However, the additional results showed that road surface had a significant effect on overall aesthetic value in road of 1993 and for 2002, 2005, and 2007 years cut slope was the most effective factor on overall aesthetic value (R2=0.675, R2=0.715, R2=0.764). Results of Kendal test showed that there is a direction and positive relation between of studied components in different years. Statistical analysis indicated that the old roads have better visual quality than new roads.Conclusion: Neglect of standards in forest road construction, Lack of suitable vegetation in cut and fill slopes and the use of low quality materials in road pavement have a negative effect on road aesthetics.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

HOSSEINI S.Z. | AENAYATI A.A.

Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    181-197
Measures: 
  • Citations: 

    0
  • Views: 

    1010
  • Downloads: 

    0
Abstract: 

  Background and objectives: This study has been undertaken to investigate effects of synthetic waste fibers of polyester in improving mechanical properties of wood plastic composites and also in reducing the accumulation of fiber listed on the environment and reduce environmental pollution through efficient use of raw waste material (polyester fiber) in human needs and in promote WPC industry and improve economic conditions in the industry. Until now, many researchers have studied variety of methods such as modification the surface fiber, use of additives materials and Hybrid to improve the physical and mechanical properties of wood plastic composite. According to researches, one of the applicative resources to improve the properties of wood-plastic composites is synthetic organic materials. Researchers in various scientific disciplines from synthetic organic materials of polymer fiber produced short fibers and have used them in various structures including concrete, asphalt and wood plastic in order to strengthen the physical and mechanical properties them.Materials and methods: Two types of polyester fibers (carpet fibers and plush fibers), high density polyethylene, wood flour of Populus, maleic anhydride grafted polyethylene (MAPE) and ethylene- glycidyl methacrylate copolymer (E-GMA) as coupling agent were used. After two-stage mixing, resulted granules were hot pressed (at160oC, under 10 Mpa pressures) to produce test boards measuring 20´20´0.7 cm in dimensions. Then to evaluate the mechanical strength including flexural strength, tensile strength and impact strength, test boards were prepared and were cute according to standard. It should be noted that were taken images by Scanning Electron Microscopy from the tensile fracture surface of composite in order to examine the effect of the polyester fibers (carpet fiber and Plush fiber) on the mechanical properties of wood-plastic composite more closely.Results: Results from measurement of mechanical properties of the samples have shown that with increasing the amount of polyester fibers (carpet fibers and plush fibers), tensile modulus of elasticity of wood plastic composites decreases and increases his flexural modulus of elasticity. Also by increasing amount carpet fibers, the tensile, flexural and impact strengths of wood plastic composites-carpet fibers increases. Morphologic study by Scanning Electron Microscopy indicates that with the increasing percentage of polyester fibers, is denser and smoother the integration between the fracture surface of the composite material.Conclusion: The maximum of flexural strength is in a sample that contained 20 wt% carpet fibers. But about the plush fiber, 10 wt% of it is efficient for increasing the flexural and tensile strengths of wood plastic composites-plush fibers.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    221-239
Measures: 
  • Citations: 

    0
  • Views: 

    818
  • Downloads: 

    0
Abstract: 

Background and objectives: Wood treatment with chemicals, especially maleic anhydride, with reducing the number of hydroxyl groups and swelling the cell wall, can be the result of reducing the moisture absorption and dimensional changes. Little evidence is presented about the effect of different conditions on wood treatment reaction with anhydrides. It is likely that the increase in a reaction temperature or time of treatment, with improvement in the hydroxyl groups substitution of the wood cell wall, has a favorable effect on the physical properties of wood. This research was conducted to determine the optimum conditions of temperature and time of treatment with Maleic anhydride and physical properties of treated poplar wood.Materials and methods: Test specimens were prepared according to ASTMD4446-05 standard. Preparations maleic anhydride solution was done with a concentration of 20% w / v in acetone as a solvent. Specimens were impregnated with maleic anhydride using vacuum-pressure method with experimental cylinder. For determination of optimum level of temperature and time, treated specimens were heated in an oven for two period time of 4 and 8h and two temperature levels of 120 and 150ºC Then, treated specimens were subjected to soaking-drying test. Finally, samples weighing and weight gain due to reaction with maleic anhydride and hydroxyl groups substitution was determined. In order to determine the optimal level of treatment, the samples were tested in four consecutive soaking-drying cycles. In each cycle, weight change and hydroxyl groups substitution were measured. At each stage of soaking- drying cycle, physical properties were easured. Also, to evaluate the chemical structure and morphology of control and treated samples, the spectroscopy test and electron microscopy images were used.Results: SEM images with cell wall swelling in treatment with maleic anhydride confirmed the reaction. Changes in weight gain, substitution of hydroxyl groups, water absorption and dimensional stability subjected to soaking-drying test were determined. Based on the results, the effect of reaction time on the measured properties was not significant. After Soaking-drying cycles, the higher reaction temperature with formation a more stable structure against hydrolysis, resulted to retain the weight gain of the treatment. In the fourth period of immersion, the highest substitution of hydroxyl groups, hydrophobicity and anti-swelling efficiency of treated specimens was observed at 150°C. Water absorption of specimens treated with maleic anhydride at 150°C decreased 61.76% compared with the control.Conclusion: Based on morphology, in treated wood, despite the increase in weight and improved anti-swelling effect, due to the entrance of maleic anhydride molecules into the cell wall, porous structure was maintained. Treatment improves hydrophobicity and dimensional stability of the treated samples. Increase reaction time treatment from 4 to 8 hours, did not cause significant differences in the measured properties, and this was confirmed in the FTIR spectrum, but a rise in temperature by effect on the connection method to polymer constituent of the wood cell wall, resulted in significant improvements in treatment reaction. In a general, conclusion can be stated that the increase in temperature of the treatment reaction with maleic anhydride, with forming more stable structure against hydrolysis, will lead to efficient stabilization.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    245-270
Measures: 
  • Citations: 

    0
  • Views: 

    998
  • Downloads: 

    0
Abstract: 

Background and objectives: Forests play a significant role for human’s wellbeing. Economists’ attention is mostly drawn on the market value of (certain) forest products. The trend, however, is changing as non-market values of forests are increasingly appreciated and measured. Recently, the ecosystem value of natural resources has been studied by natural resource economists and its role on human welfare is ensured. These studies had made a considerable progress in valuation of environmental and ecological services, which was offered by ecosystems. There are different methods assessing environmental economy based on revealed and stated preference for measure of environmental values. The subjects of this research are the determination of recreational value of Ghorogh Forest Park and measure of individual’s willingness to pay (WTP) based on contingent valuation (CV) and dichotomous choice (DC).Materials and methods: Various approaches may be used in environmental economics to measure environmental values; these may be divided into revealed and stated preference methods. Revealed preference methods are based on how individuals actually behave, whereas stated preference methods are based on how individuals say they would behave in a hypothetical situation. In this study, we were interested in assessing the value of forest recreational to the public, measured in terms of whether people would be willing to pay towards forest recreational. The logit model was used for measuring individuals WTP. This study utilizes the DC questionnaire to measure the individual’s WTP in the CV surveys. The single bounded dichotomous choice approach was first employed by Bishop and Heberlein (1979). It involves assigning a single bid from a range of predetermined bids that potentially reflect the maximum WTP amounts of the respondents for a particular good. The double-bounded dichotomous choice questionnaire, therefore, was designed for acquiring individual WTP to determine the existence value for Ghorogh Forest Park. This questionnaire for interviews was carefully designed to provide respondents with adequate and accurate information, making them fully aware of the hypothetical market situation. This information from the CV questionnaire was intended not only to help them reveal their true values as accurately as possible, but also to reduce the rate of rejection from the respondents. Estimation parameters of the model are based on the method of maximum likelihood (ML).Results: Results showed that variables of visiting first, other purposes of travel, education, income, gender and bidmount are effective factors in WTP. The mean of WTP for recreational value of this rangeland is 6416 Rial that represents a very important recreational resource for visitors.Conclusion: Also, results revealed that forest parks had considerable recreational values. Thus, these values provide enough justification for policy makers to maintain the quality of forest park, and avoid degrading forest resources.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    271-288
Measures: 
  • Citations: 

    0
  • Views: 

    1281
  • Downloads: 

    0
Abstract: 

Background and objectives: Increasing of population and daily increasing of demand for wood products caused reduction in forest areas, so that concerning trees cut, serious regulations have been developed. Intensive pressure of Iranian environmental organization has seriously raised up the argument of harvesting stop and amount of wood harvested from forests has lowered to less than one million cubic meters. Therefore, wood industry is facing wood shortcoming. (12).The aim of this study was to recycle fibers from waste panels applying ecofriendly electrolysis method and reusing them for MDF production.Method and Materials: In this study, first waste wood panels of MDF were collected from several firms. Waste panels were cut into small pieces and immersed in hot water for 24 hours. Immersing was conducted in order to penetration of water into the waste MDF before Ohmic heating. Small pieces of wet MDF were placed in a cylinder equipped with electrical steel electrodes. Rectangular electrodes were fixed parallel to each other in the side walls of cylinder. After 45 minutes, MDF fibers were separated by hydrolysis. In order to increase electrical conduction, some salt was added to the mixture. Obtained fibers were separated and dried and mixed with fresh fibers provide by a local firm (up to 30% of oven dry weight of total fibers) for board producing. UF resin was modified by adding nano- cellulose at three levels of 0, 1 and 3 percent. Resin UF was applied at two levels of 8 and 12 percent.Findings: Manufacturing parameters such as press temperature of 160 degree centigrade and press time of 8 minutes were kept constant for all treatments. Physical properties of thickness swelling (TS) and water absorption (WA) after 2 and 24 hours water immersing in water and mechanical properties of internal bond (IB), modulus of rupture (MOR) and modulus of elasticity (MOE) of boards were evaluated. The results showed that the highest modulus of rupture (14.47Mpa) and modulus of elasticity (1359.096 MPa) of the boards made with 12% glue and 3% nano- cellulose was, as well as the highest internal bonding in the boards made with 12% glue and 3% nano- cellulose was (0.5 MPa). The least amount of thickness swelling (%4.720 and %9.863 after 2 and 24 hours floatation on water respectively) was observed in boards made with 12% glue and 3% nano- cellulose. As well the least amount of water absorption (%33.113 and %80.653 after 2 and 24 hours floatation on water respectively) was observed in boards made with 12% glue and 3% nano- cellulose.Conclusion: Statistical analysis of results was conducted using SPSS 16. Results showed that recycled fibers have suitable quality. It is possibility to reuse it mixed with fresh fibers. Manufacture board properties, however, are not as high as standard. Adding nano-cellulose into UF glue caused an improvement in mechanical properties and water absorption and thickness swelling were decreased.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    289-308
Measures: 
  • Citations: 

    0
  • Views: 

    1270
  • Downloads: 

    0
Abstract: 

Background and objectives: Because of some unique features such as high thermal stability, low heat transfer coefficient, desirable resistance to wear and corrosion, and catalytic activity, composites and ceramic porous substrates can be used under more difficult conditions compared to metals, glass, and porous polymers. Due to these features, ceramics have found a broad spectrum of industrial applications including the production of industrial filters. This article deals with production and evaluation of the efficiency of ceramic filters that contain pyrolyzed particles of wood flour with the purpose of removing the heavy metal cadmium from aqueous environments. Separate utilization of ceramic materials and lignocellulosic materials in removal of heavy metals, given the positive environmental features of these materials, has become the focus of attention of researchers for several years. Use of these materials in combination with each other in the form of composite filters can increase their efficiency and length of useful life and expand the range of their applications. This article introduces a simple and cost-effective method for manufacturing ceramic composite filters that contain a discontinuous carbon phase and were very capable in removing the heavy metal cadmium from aqueous environments because they utilize the synergistic effect of an organic and a mineral phase.Materials and methods: 40 and 80 mesh Paulownia wood flour was prepared as the source for the carbonized lignocellulosic filler phase and was mixed with ceramic powder obtained from a ceramic manufacturing factory with the weight ratios of 5, 10, and 15% (dry weight basis). Water was added to the mixture to prepare ceramic grout, which was cast in wooden molds designed beforehand. After several days, the air-dried ceramic samples were removed from the molds and transferred to an induction furnace for pyro processing. The ceramic substrates were pyro processed at 1100˚C for 50 minutes for partial sintering. During the pyro processing process, particles of wood flour added inside the ceramic matrix substrate were carbonized under the influence of increased temperature and insufficient oxygen supply. A field emission scanning electron microscope (FESEM) and density determination were used to evaluate the distribution of the organic phase and the porosity of the structure of the carbon-ceramic composite that was made. Furthermore, the effects of the parameters of pH, contact time, temperature, cadmium concentration, and the adsorbent dose on the degree of cadmium adsorption by the manufactured composite were studied.Results: Adding wood flour to the ceramic substrate made it porous and decreased its density. Results showed the effects of the weight ratio and of the size of wood flour particles on the density of the manufactured carbon-ceramic composite were significant. Stereomicroscopic and EF-SEM micrographs indicated the presence and uniform distribution of the carbon phase inside the ceramic substrate of the manufactured composite. Moreover, results showed the maximum cadmium removal from the aqueous solution happened at pH 6, cadmium concentration of 10 mg/l, adsorbent dose of 0.3 g/l, temperature of 35˚C, and contact time of 60 minutes.Conclusions: As a general conclusion, we can say that, considering the low cost of the raw materials and the easy manufacturing process and the high removal efficiency, the manufactured carbon-ceramic composite can be recommended as an efficient filter for removing the heavy metal cadmium from aqueous solutions.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

PARSAKHOO A. | YAZARLOU H.

Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    3
  • Pages: 

    309-328
Measures: 
  • Citations: 

    0
  • Views: 

    855
  • Downloads: 

    0
Abstract: 

Background and objectives: Animal trails are the primary wood hauling trails from stump location to the log depot. These trails are created by animal passes. Steep terrain and inability of skidders for passes from these areas, incomplete access forest roads, inadequate skid trails, low timber volume per hectare and environmental pressure in the unstable and steep terrain cause to use mule logging system in some regions of northern forests of Iran. The aim of this research was to investigate the effects of the longitudinal slope of trail used by mule for wood extraction and number of mule passes on soil compaction and porosity. In addition, the optimum soil moisture was determined for scheduling mule logging in forest to reduce site damage.Materials and methods: A mule trail with downward direction was selected in Saad Abad forestry plan. Trail was classified into 0-10, 10-20 and>20% with respect to longitudinal slope and classified into 2, 4, 8 and 12 passes with respect to the number of mule passes. In each class the soil bulk density or compaction, porosity percentage and soil moisture at mule spoor were sampled using metal cylinder and then laboratory measurements. Experiments were done based on factorial design with two main factors of mule passes in four levels and longitudinal slope in three levels. Totally, 12 treatments plus control treatment was performed in SAS software.Results: Findings showed that soil bilk density increased and soil porosity decreased with increasing the longitudinal slope of trail. Moreover, soil bulk density increase rapidly with increasing mule passes. In 8th pass soil reach to its maximum bulk density and then increasing passes hadn’t significant effect of soil compaction. Interaction effects of passes and longitudinal slopes on soil moisture were significant at the probability level of 99%. R2 values showed that variations in most models could describe more than 80% of variation in relationship of soil bulk density and soil moisture. The value of optimum moisture for reducing soil compaction by mule was 35-40%.Conclusion: It was concluded that in steep slopes and high number of passes, the rate of soil compaction was more. Therefore, before wood extraction in such conditions it is necessary to determine the optimum moisture of soil to schedule logging operation and reduce damage to soil.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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