Journal of Wood and Forest Science and Technology
Year:2017 | Volume:23 | Issue:4|Papers Count:22

Background and objectives: The forest as one of the most valuable terrestrial ecosystems has played important roles in supplying the human needs from the past to present. The stability of a forest is depended on its soil nutrient maintenance and understanding soil properties can be considered as one of the basic principles of forest management. Macronutrient stocks are among the important indicators to evaluate the effect of tree species on ecosystem function. Several studies have examined the effects of overstory layer on soil properties indicating a significant effect of over story tree species on soil productivity. Therefore, the aim of the present study was to evaluate the role of forest ecosystems in soil characteristic variability as well as to compare the possible changes in the soil of forest ecosystems with control area.Materials and methods: In the present study, the effect of overstory layer on soil physicochemical properties of natural and planted forest stands in Chamestan region, Noor, in the Hyrcanian forests of northern Iran was evaluated. In order to investigate some of the indicators of soil productivity in the study area in each of the stands, including natural forest (Acer velutinum Boiss, Zelkova carpinifolia (Pall), Parrotia persica (DC.) C.A.Mey, Quercus castanifolia C.A. Mey, Carpinus betulusL), Mixed planted stands (Acer velutinum, Ulmus carpinifolia G. Suckow, Quercues castanifolia, Carpinus betulus L, Tilia begonifolia Scop. Subsp. caucasia (Rupr.) Loria), maple (Acer velutinum Boiss.) plantation, pine plantation (Pinus taedaL.) and a clear-cut region (control) a number of 16 soil samples were taken at two depths of 0-15 and 15-30 cm. Soil samples were air-dried and sieved with a 2mm sieve then transported to the laboratory for measuring concentrations of macronutrients such as, nitrogen, phosphorus, potassium, magnesium, calcium, and some physicochemical properties such as percentage of the components constituting texture and water content and ratio.Results: The results showed that soil texture components except sand, were significantly different between the stands, but were not significantly different in different soil depths. Moreover, there was a significant difference between stands and depths in terms of water content and ratio, as the highest amount of water content of 19.34 and 18.77 percent and ratio of 12.91, 11.75 were related to pine plantation and first layer, respectively. Measurements of soil nutrient stocks showed that fertility decreased in relation to increased soil depth, with significant differences depending on soil depth. Likewise, the result of soil macronutrient stocks revealed the highest amount of total nitrogen stock for mixed plantation and the highest amount of available phosphorus stock for maple plantation. Further, pine plantation had the highest available potassium stock than other treatments.The highest available magnesium and calcium stocks were found in natural forest and control area, respectively.Conclusion: As a conclusion, the broad-leaved species were more successful about most of the nutrient stocks than needle-leaved stand and control area.

Background and objectives: Wild pistachio (Pistacia atlantica Desf.) trees have social and economic importance due to resin exploitation and its great role in supplying livelihoods for forest dwellers of Zagros regions. The purpose of this study was to investigate the response of wild pistachio (Pistacia atlantica Desf.) to resin exploitation. In this research, biometric indices of wild pistachio trees (collar diameter, total height, trunk height, trunk height to total height ratio, crown height and crown area) were used to assess the impact of resin exploitation on wild pistachio trees.Materials and methods: Two stands including an abandoned stand (resin had been exploited in the past, but it had ceased for the past 22 years (1991-2013) with an area of 4.8 ha and an utilized stand (undergoing resin exploitation) with an area of 9.6 ha, with similar physiographic conditions were selected in the villages Bivandbala and Bivandpaeen, Javanroud, Kermanshah province. In the two selected stands, a full callipering was performed. We recorded the tree species and collar diameter for all trees with the collar diameter larger than or equal to five cm. Moreover, total height, trunk height and crown diameter were measured in wild pistachio trees.Results: The results showed that the mean of biometric indices of wild pistachio such as collar diameter, total height and crown height in identical diameter classes were significantly different between the two studied stands. The value of studied variables was higher in abandoned stand except collar diameter. Trunk height, trunk height to total height ratio and crown area did not show any statistically significant difference between the two studied stands.Conclusion: Resin exploitation is an important source of income for forest dwellers in the northern Zagros. The traditional resin exploitation method is ecologically and economically inefficient. To improve the livelihood of forest dwellers, it is necessary to replace the traditional method with a scientific method which is economically and ecologically sustainable. In addition to the traditional resin exploitation, the absence of regeneration of wild pistachio is a threatening factor for existence of these stands. The main objective for a policy maker should be ensuring the sustainability of wild pistachio stands and the continuity of resin exploitation income for the next generations. Therefore, it is necessary for conservation authorities to make the prerequisite of seed regeneration, maintenance and warranty of regeneration establishment in wild pistachio stands instead of attaining interest and toll for issuing resin exploitation contracts.

Background and objectives: The quantitative description of forest structure is considered as one of the most useful working tools in modern forest management and in order to manage these ecosystems optimally, obtaining accurate insight of their structures is necessary. This study aims at evaluating the optimal area of the sample plot for correct and effective estimation of structural parameters of beech stands.Materials and methods: For this purpose, a compartment with an area about 48 hectares in Gorazbon district in research forest of Kheirod, Nowshar, Iran was selected in which tree species and DBH of all trees with DBH>7 cm were recorded. In addition, for stem mapping of trees, the location of each tree was obtained using azimuth and distance method. The square sample plots with different areas were laid out on the simulated map of study area and nearest neighbor of spatial indices (spatial pattern index of Clark and Evans, mingling index, diameter differentiation index, relative mingling index) were then calculated in each sample plot. The calculated indices in each sample plot with different areas were then compared with full inventory data using one-sample t-test.Results: The comparison of resulted spatial indices in each of sampling schemes (1000, 1500, 2000, 3000, 4000, 5000, 7500, 10000 and 12500 m2 sample plots) with calculated spatial indices for the whole of study area indicated that only spatial indices in sample plots with area of 12500 m2 did not show any significant difference with the spatial indices for the whole of study area. Values of other spatial indices i.e. mingling index, diameter differentiation index, and relativemingling index obtained from 1.25 ha sample plots are in agreement with full inventory data; that is, mingling index represented low species mixtures in the study area and diameter differentiation index was in mid-class, and relative mingling index was greater than one.Conclusion: As long as the topographic and forest site conditions as well as the management system does not change, horizontal structural indices could be investigated with one 1.25 ha sample plot, provided that this sample plot is not established in the margin of compartment and the forest road vicinity.

Background and objectives: Few studies have shown the effect of the topographic gradient in the distribution of trees and coarse woody debris (CWD), particularly old-growth beech stands. Several studies emphasized relationship between physiographical characteristics of sites and live trees distribution. Valipour et al (2013) studied the effect of physiographic characteristics of sites on dimensional properties of tress. They found that physiographic factors significantly effect on the dimension of trees, the most important factors influencing are the slope. Furthermore, Alavi et al (2008) revealed that physiographic factors impact on spatial distribution of elder. Research in the low land forests of Noushar region showed the slope and altitude positively affect on diversity of indices. The main goal of this research is (1) Evaluation the effect of geomorphic characteristics of sites on living tree distribution and (2) extent and distribution of dead trees.Materials and methods: The study was conducted within the Gorazbon section of the Kheyrud Experimental Forest in northern Iran, which is owned and managed by the University of Tehran for education, research, and conservation. The site selection was done according to the management history. Selected site was undisturbed and logging operation doesn't was done by now. To characterize coarse woody debris within stands, 50×50 meter gird grid of sampling points established to randomized plot selection and thirty-five 0.1 ha circular plots were established within a natural beech stand using a systematic random sampling technique in order to equally sample across a wide variety of topographical factors.In each plot, we measured percent slope, aspect and land form. Meanwhile, the number of dead trees and species and quality was recorded. Therefore, we investigated the influence of topographical factors, including slope aspect, slope degree, and landform index (LI) on the distribution of dominant tree species and CWD in undisturbed mixed forests in northern Iran.Results: F.orientalis had the highest mean density, volume, relative density, relative volume, and RIV of all live and dead trees. Results showed that tree density and basal area were not significantly correlated with any of the measured parameters, except basal area was negatively correlated with LI. Redundancy analysis (RDA) of the tree layer revealed a significant relationship between the measured environmental variables and species distributions on the first canonical axis and all four canonical axes. CWD volume showed significant negative correlation with percent canopy cover and was highly correlated with terrain shape index. Density of CWD in decay class IV was significantly correlated with aspect slope and percent of canopy cover.Conclusion: Analyses of CWD distributions in relation to both living vegetation and topographic gradients showed a highly complex interplay of factors dictating the distribution of CWD across the forest stands.

Background and objectives: Density (i.e. number of trees per hectare) in a forest stand shows status of the stand and its monitoring is important to assess the stand’s changes. In addition, understanding about density trees of forest stands is one of the primary proceedings in forest management. In this study for estimation and mapping density trees of Oak Forest used Geostatistics (Variogram modeling and Kriging interpolation) and Worldview-2 satellite images in Google's earth database. Study area was a 450 hectares forest area in Ilam province, southwest of Iran.Materials and Methods: Field's sampling was performed based on a 100 ’ 250 meter systematic network inventory using 2500 m2 square samples on the Google Earth image. The image used in this study, was received from Google ’ s earth server to high spatial resolution from the Worldview-2 sensors (0.46 meter). The image was geo-referenced using the ground control point (collected with GPS) in the Universal Transverse Mercator (UTM) system. Overall, 180 sample plots were established and measured on the geo-referenced image received from Google's earth server. For validation of density measuring on Google's earth image, 30 sample plots were randomly selected and measured in the field, which result of t-test showed that no significant differences. Experimental variograms for forest stem density was calculated and plotted using the geo-referenced inventory plots. Then deferent theoretical variogram model (Circular, Spherical, Exponential and Gaussian Models) fitted to Experimental variograms for forest stem density and selected best theoretical variogram model for estimation stem density based on good of fitness.Results: The calculated variogram of stem density showed strong and anisotropic spatial autocorrelation, which best fitted by exponential theoretical model. Estimations were made by ordinary block kriging method (block size 50 ’ 50 meter).Cross-validation results showed that all the estimations are unbiased. Thus, kriging and Worldview-2 images from Google's earth database together have the potential to estimate and map the density trees of this kind of oak forests, accurately. The results of this study show that the Google earth images sampling absence of significant differences with ground sampling, so that the results of this study can decrease the cost sampling and resolve many restrictions of fieldwork.Conclusion: Consequently, Mapping Density tree using Kriging and Google Earth Images was more efficient for the oak density estimate in the study area. Also according to the results, we suggested that in the other area of Zagro's forest is used from Mapping Density tree using Kriging and Google Earth Images to be more results that are reliable.

Background and objectives: Estimation of trees biomass with the highest accuracy is the basis of forest management with respect to the sustainable development. Furthermore, that is one of the most important fundamental issues of C sequestration to international communities to challenge the global warming. Modeling bole biomass of maple trees was carried out in Samunsi forests of Chamestan through allometric equations and by artificial neural network (ANN) to achieve the highest accurate prediction.Materials and methods: After felling of 20 individual trees from different diameter classes, each part of bole which had been converted was weighed in the field. As such, one disc was taken from each part of the bole. The samples with constant volume, extracted from each disk, were taken to lab and were oven-dried at 105°C for 24 hours. To develop the model, power function was basic allometric equation and transfer function of Log-sigmoid and of Tan-sigmoid was introduced in the various topologies of network of FFBP. Biophysical variables such as diameter and bole height were introduced in the modeling process.Results: The results showed that the exponential multiple regression including diameter and height with the correction factor of 1.04 (CF=1.04) was the optimal allometric model (S=0.23). Pertaining to the ANN, some of the outputs with different topologies consisting of Tansig and Logsig had less accuracy compared to allometric equations presented in this research. Associated with the least mean squared error of the of the data in the different epoch as well as considering average standard deviation the best model in ANN was selected. Furthermore, theresults showed that the model having input layers of diameter and height with onehidden layer and number of 10 neurons including Tansig function is the best model (S=0.1) to predict bole-mass with higher accuracy and certainty.Conclusion: The majority of studies, related to biomass and carbon sequestration modeling carried out in the various biomes, indicated that allometric equations including diameter and height with different incorporated variables are the best predictors with the highest accuracy. However, the final result of this study showed that the architecture of optimal topology in the ANN induced more accurate prediction of biomass compared to allometric equations.

Background and objectives: Spatial prediction of fire risk and preparing the forest fire risk map across the natural areas are among the ways that can be used to prevent and to manage fire. The aim of this research was zonation of forest fire risk in Golestan National Park using non-parametric algorithms, namely Artificial Neural Network (ANN), Support Vector Machine (SVM) and Random Forest (RF).Materials and methods: About 100 occurred fire points were considered for modeling the fire risk. The effective factors on fire occurring including vegetation types, physiographic, climatic, and human factors were identified and their relevant maps were prepared from different sources. To modeling purposes, initially the zone was divided into 1-ha levels of decision-making and modeling and then the pixel values of the effective factors on classes of fire occurring, across the 1-ha levels, were extracted and standardized. Based on non-parametric algorithms, fire risk was modeled with 70 percent of the fire points, as training samples. The prepared forest fire risk map was zoned in terms of four classes of low-risk, medium-risk, high-risk and dangerous. The classification accuracy of the maps, resulted from this modeling, was assessed through the overall classification accuracy given 30 percent of the remained fire points.Results and Conclusion: The results indicated that RF algorithm, with the overall accuracy of 75%, was the best algorithm in predicting the fire risk compare to other ones. Likewise, after matching the fire risk occurring with the results gained from algorithms, it turned out that all algorithms were able to classify the area properly in terms of the fire risk, as more than 80 percent of fire points were placed in the high-risk and dangerous classes.

Background and objectives: Chestnut-leaved oak is one of the most important northern Iran forest trees that is planted in broad scales in degraded areas of its natural sites. According to deep rooting of Chestnut leaved oak seedlings in nursery bed, root undercutting is the inevitable practice in bare root seedlings of this species. Studies showed that late root undercutting in nursery can negatively affect seedling survival and performance in planting site. So far, many efforts were done to determine the suitable time of root undercutting in some species of Quercus genus, for example, in Lebanon's oak and Sessile oak. Because, root undercutting along with growing season can increase drought stress in seedlings and, as a result, can decrease nursery production efficiency, this study aimed to investigate the effect of root undercutting and irrigation period on bare root seedlings of Chestnut leaved oak simultaneously.Materials and methods: Present study were conducted in Golestan province Ghorogh nursery, so that using a randomized complete-block split-plot design with three replications, effects of root pruning time (pre-summer, late- summer and control) using horizontal blade attached to tractor, and furrow irrigation period (2, 4 and 6 days) on Chestnut-leaved oak bare root seedlings production efficiency and growth characteristics were investigated. At the end of growing season survival and growth characteristics of seedlings were recorded and analyzed using univariate ANOVA and Duncan multiple rage test of means techniques in 0.05% experimental error probability.Results: The results showed that irrigation period was significantly affected seedlings root dry weight and quality index (QI), so that minimum and maximum amount of seedlings root dry weight were detected in 2 days and 6 days respectively. Also, use of horizontal root undercutting (in different irrigation periods), especially in early summer, significantly increase seedlings root growth trait (volume, length, diameter, area and dry weight) and QI. Furthermore, the results showed that root undercutting in early summer with irrigation period of 6 days is the most suitable treatment for growing Oak seedlings in the study area.Conclusion: Based on this study's finding, it can be stated that horizontal root undercutting and irrigation period are essential factors that should be considered in oak seedlings root growth and seedlings quality enhancement practices. Because, the more root system density, extending and frequency, the more nutrient and water absorption potential in seedlings, and such planted seedlings can better resist to harsh environmental condition and establish in the forest planting site.

Background and objectives: Wood plastic composite that briefly (WPC) are called are a new class of composite materials that in recent years have been attended by many researchers and industries. Since, the major part of these composites is the wood flour, these composites such as wood are moisture absorbent. So, this research with aim of evaluation the effect of chemical modification of wood flour on long-term water absorption and thickness swelling, humidity coefficient diffusion, thickness swelling rate and morphological study of wood plastic composite was done.Materials and methods: For this purpose first, wood flour with acetic acid, benzyl chloride and sodium hydroxide were modified separately. For ensure the chemical modification, Fourier transform infrared (FTIR) spectroscopy tests was done. Wood flour (60 wt %), polypropylene and MAPP (4 phc) were mixed by extruder and the test specimens were fabricated using the injection molding machine. According to the ASTM D 7031-04 standard, the long-term water absorption and thickness swelling were measured. Morphological study of wood plastic composite was done by scanning electron microscopy.Results: The result showed that long-term water absorption and thickness swelling, humidity coefficient diffusion and thickness swelling rate decreased by chemical modification of wood flour. The Result of infrared spectroscopy revealed that the chemical modification of wood floor caused to decrease the intensity peak of hydroxyl groups. Scanning electron microscopy images showed that chemical modification of wood flour led to improve the interface between wood and plastic. The highest weight percentage gain of wood flour was observed for modification by benzoylation.Conclusion: The chemical modification of wood flour for improvement of the interface between two phases of wood and plastic is a good idea. This modification reduces the radius of irregularly capillary tubes in wood plastic composite and decreases the available hydroxyl groups for creating hydrogen bonds with water molecules. These factors improve the physical properties of wood plastic composite, such as water absorption, thickness swelling.

Background and objectives: Literatures review show that fungal pre-treatment of chips before original cooking caused to improve in pulp bleachability, reduction in bleaching chemical consumption in the chlorination phase to 9%, increasing in brightness of bio-Kraft pulp with similar bleaching sequence to 8%. In addition, chemical consumption during ECF bleaching of Kraft pulp has a high correlation with kappa number measurements. Furthermore, by evaluation of bleaching spent liquor by the spectroscopic method could be assessed content and type of chlorine used in different sequences of bleaching. Hence, in this research, Bio-Kraft pulps made from poplar chips pre-treated by Trametes versicolor in 1, 2 and 3 weeks, were bleached in ECF method (DED sequence) for evaluation of their bleachability.Materials and methods: Accordingly, in this study, pulps were characterized in lignin content, bleaching yield, Hexenoronic acids (Hex-A), viscosity and efficiency of fungal pre-treatment on chemical consumption before and after each stage of above-mentioned sequence. Then laboratory handsheets were made from above bleached pulps and tested in optical properties.Results: Results showed that there are approximately reductive trends for kappa number from the first phase to third phase, which is normal based on the target of sequence bleaching. Interestingly, kappa number was enhanced by increasing in pre-treatment time expect third phase of 3-week pre-treatment samples. It's due to non-selectivity of T. versicolor that caused more degradation of carbohydrates due to acidic groups creation specially Hexenoronic acids. These acidic groups were led to wrong measurement of kappa number as more. By progressing in bleaching from phase 1 to phase 3, bleaching yield was increased except 3-weeks pretreatment samples. Also, after bleaching, viscosity of pulps was decreased.Conclusion: In total, fungal pre-treatment of poplar wood has been effected on its pulp bleachability that chemicals consumption was decreased in bleaching process and also adsorption values of chemicals of spent liquor that measured by UV-Vis in 257, 280, 289 and 355 respectively for ClO2, soluble lignin, ClO- and ClO2- increased. Paper brightness was increased by decreasing in lignin content during bleaching process.

Background and objectives: In recent years, natural fibers have made significant contributions to the plastic industry, which has led to the emergence of wood plastic composites (WPC) in the construction industry. Products such as decking, fencing, siding, window framing, and roof tiles are being introduced into the market. The uses of wood plastic composites are also increasing in automative, transportation, military, and etc. Despite the widespread application, the natural fibers have some disadvantages, such as lower processing temperature, and incompatibility between the hydrophilic fibers and hydrophobic polymers. This problem can be alleviated by incorporation of coupling agent into the compound and modification of the fibers. This research was carried out to investigate on the effect of chemical modification of wood material on the thermal properties and wettability of wood flour- polypropylene composites.Materials and methods: Firstly, the different chemical treatments on wood flour, namely mercerization, acetylation and benzoylation were done. Then, the chemically treated fibers with polypropylene and coupling agent were compounded by an internal mixer, and samples were fabricated by injection molding. The weight ratio of wood flour was 60% based on the total weight of composites. The amount of PP-g-MA as was fixed at 2 phc for all formulations. Thermal properties and fractional crystallinity of samples were studied by thermogravimetric analysis (TGA) and differential scanning calorimetriy (DSC), and then compared with those of untreated samples. The wettability of chemically treated samples were alsomeasured by sessile drop method to determine the water repellency, and compared with those of untreated samples.Results: Results indicated that the thermal stability of composites increased by applying chemical treatments due to improving the interface adhesion and good wettability. Furthermore, the fractional degree of crystallinity of chemically treated samples increased due to the growth of crystals and the formation of nucleates in the polymer matrix. Furthermore, the distributions speed of the water droplet on the samples decreased by applying chemical treatments due to the increasing of contact angle evolution time of the water droplet on the sample surface. FTIR spectra of treated fibers showed that the intensity of the bonds at 3400 and 1740 cm-1 change due to reaction of O-H groups and formation of ester groups in samples.Conclusion: Based on the findings, it can be concluded that the chemical treatments have improved the thermal stability and hydrophobicity of composites.

Background and Subjects: Todays, the satisfaction isn't the final key to success and profitability, and the marketing concepts that have been insisting lately on this matter, don't recognize it anymore, thus today only customers who have a sense of belonging to the organization are counted as profitable and long-term capital for organization. To keep and maintain a customer in Corrugated Box Making industry contains a large share of sale security and stability in the competitive market. Strengthening commitment in buyers of corrugated board products leads to the survival of the production units. Researchers' have investigated the factors affecting the commitment and behavior of customers in different industries. But in the corrugated board and packaging industry that their increased industrial activity thrives on industrial exchange in each country, it is not practical. Accordingly, the aim of this study is to identify factors affecting the commitment and behavior of customers in the corrugated board production units in order to offer the solutions to the continuity and quality of its relationship.Material and Methods: Information of the survey is gained through library research, reviewing canons, and interviews with experts regarding the subject's matter of the survey. Then all indices were considered in a questionnaire designed by the researcher standards. The questionnaire was distributed among a sample of the target population. The study consisted of customer and consumers of corrugated board products in Tehran. After sending questionnaires to managers, supervisors, company executives, Consumer and buyer of corrugated board products a number of 150 of them was received. Preliminary evaluation of questionnaire was conducted in the form of descriptive statistics. Then, using a model of research the effect of seven factors related to the intensity of emotions, mutual trust, interdependence, interpersonal factors, and the quality of the relationship with commitment and behavior of buyers of corrugated box making industry was investigated. Received data was analyzed by using factor analysis and structural equation modeling (SEM).Results: Data analysis showed that the factors of mutual trust and interpersonal relationships between customers and sellers in corrugated board products industry have the greatest impact on customer commitment. While the intensity of feelings in corrugated board products industry has less impact on customer commitment. However the other factors in the research influenced the research subject too.Increased commitment in customer of corrugated board products industry, lead to increased buying behavior of the industry, which itself finally leads to increase in profits of firms. The cost for manufactures in corrugated board products reduced by increasing desirable behavior in customers of industry.Conclusion: The commitment is very important on the relationship between buyers and sellers in corrugated board industry. Some of the benefits that gained the marketers their business are the buyer commitment in corrugated board industry. It is achieving their suitable behavior that reduces costs and increases profits of seller firms. The findings suggest that managers and directors emphasize the commitment of customers and in order to increase their of commitment to causes of interpersonal trust they should pay more attention.

Background and objectives: The collection and consumption of recycled paper in addition to helping environment protection, causes more economical paper production. Since the consumption of recycled pulps causes low quality paper production, so determination of OCC pulp quality can be useful for the better fluting paper properties prediction For OCC production, it is possible to use all types of paperboard and cartons from different sources. Because of using different recycled paperboard and cartons for OCC production, the OCC pulps quality are difference. As the fiber length distribution and variation have the important role in paper strength quality, the aim of this study is the determining of different OCC pulp's fiber length variations effect on fluting paper quality.Methods and materials: From the four types of recycled paper with different quality and with different sources, the OCC pulp was prepared. The NSSC pulp and recycled pulp samples fiber length classification were done by Bauer McNett fiber classification system based on Tappi standard method, T 233 cm - 82, in Mazandaran Wood and Paper industries (MWPI) mill laboratory. The NSSC pulp prepared from wood of Iranian hardwoods in MWPI used as the control sample. The 127 grams handsheets, were prepared according to Tappi standard method, T 205om-88 for measuring structural (density) and strength properties (tear strength, burst strength, breaking length and corrugated medium test) of fluting paper.Results: The results have shown that, OCC pulps from different recycled paper, have different long fibers and different fines. Among the different OCC pulps, the pulps with the higher amount of long fibers, have more paper strength properties (tensile (breaking length), burst, tear), and the pulps with the higher amount of fines and lower amount of long fibers, have the least paper strength properties. The corrugated medium test (CMT) of fluting paper is one of the important properties and the results showed that this strength also depends to long fibers and fine contents in OCC pulps. The OCC pulps with the higher amount of long fibers and lower amount of fines, have more CMT.Conclusion: OCC pulps produced from different paper sources have different fiber length distribution that have a significant impact on the fluting paper strength properties Therefore, with doing the fiber length distribution tests it is possible to predict fluting paper strength properties OCC pulps with higher amounts of long fiber and lower amounts of fines has good strength properties (tensile strength, burst strength and tear strength) for producing fluting paper.

Background and objectives: The strength and barrier properties are some of the most important required features for kinds of paper, especially printing and packaging paper. So one of the important research areas in the paper industry is researching to improve these properties. In this research for the first time, the artificial neural networks (ANNs) were used to predict the strength and barrier properties of nanofibrillated cellulose reinforced acetylated papers.Materials and methods: Nanofibrillated cellulose (NFC) was produced from bleached commercial pulp using grinding method. Paper modification was performed using two methods including acetylation of pulp fibers before paper-sheet making, and acetylation of made paper-sheet. Pulp and paper acetylation process was performed in liquid phase at 70 °C for 0.5, 1, and 3 hours. The success of chemical modification was confirmed using Infrared spectroscopy. Two kinds of paper (unmixed and mixed paper) were made. The paper properties, including thickness, basis weight, bulk, breaking length, tear strength, and water barrier property were measured. In order to design an artificial neural network, the type of treatment (treatment of fibers and paper treatment), treatment time (0.5, 1, and 3 h), and types of paper (unmixed and mixed paper) were considered as input data, and the physical, mechanical, and barrier properties of the paper (bulk, breaking length, tear index, and water absorption) were considered as output data.Results: Among all the papers, the weakest strength and barrier properties were obtained for the paper made from the acetylated pulp. The best paper properties were obtained by the acetylation of paper. According to the results, the acetylation of paper had no significant effect on the physical and mechanical properties of produced papers (p>0.05). Acetylation led to decrease in the water absorption of unmixed and mixed papers about 24.5 and 48%, respectively. Generalized feed forward artificial neural network with one hidden layer, Tanh axon- transfer function, and momentum as learning rule was chosen as the best network.Conclusion: The designed artificial neural network could predict the paper properties with high correlation coefficient (R2=98.11).

Literature and purpose: conventional alkaline deinking has some limitations such as yellowing mechanical fibers in alkali environment (alkaline darkening), low yield due to the dissolution of most of the material in the presence of chemicals, increasing costs and water effluent result from chemicals such as sodium hydroxide and sodium silicate. These limitations caused trends to reduce the pH of repulping to a neutral level, which is known as neutral deinking. This study was done to investigate the possibility of using neutral deinking as an alternative for alkaline conventional deinking of mixed office waste papers, to reduce the problems like alkaline darkening and waste waters pollution load.Materials and methods: Mixed office waste papers was treated using sodium sulfite at three levels of 1, 2 and 3 percent (base on oven dry weight of pulp) at treatment times of 15, 30 and 45 min. The physical, mechanical and optical properties of deinked pulp were measured according to standard TAPPI test methods.Results: The results of the Scoring equation shown that treatments A, B, C, D, E, F, G, H and I, have scores of 1.5095, 1.4517, 1.4735, 1.407, 1.4875, 1.4843, 1.5416, 1.5266 and 1.4963 respectively, And blank treatment with 5821/1score among all treatments was rated higher. But among neutral deinking treatments, G and H are the highest ratings. Which has 3% sodium sulfite and time are 15 and 30 minutes respectively. So, the use of 3% sodium sulfite as the optimal value for the chemical treatment that can replace for chemicals in conventional methods, such as sodium hydroxide, hydrogen peroxide, sodium, etc. Times 15 and 30 had a better condition than 45 minutes; it can be used as chemical treatment time in the re-pulping stage.Conclusion: The results showed that treatment with 3% sodium sulfite for 15 and 30 min had better results than other treatments. Furthermore, scoring method indicated that treatment by 3% sodium sulfite for 30 min which used for deinking of MOW pulp had higher score compared with other treatments and also conventional alkaline deinking treatment. In other words, it has the best results in both optical and mechanical properties. The results of optical and mechanical investigations of this treatment were close to the conventional alkali treatment and can be the suitable alternative for conventional method.

Background and objectives: As renewable resources, agricultural wastes such as bagasse can be used as raw materials for making cement-bonded particleboard (CBPB). Also for improving cement-bonded particleboard properties by increasing the hydration speed, some methods such as water leaching and additives must be examined to eliminate or mitigate harmful substances and increase the compatibility between organic material and cement. So, the present research is aimed at studying the effect of water-leaching treatment of bagasse and MgCl2 additive content on properties of cement-bonded particleboard.According to the results of the research by Govin et al. (2007), thermal treatment of wood creates dimensional stability, reduces the fibers' hydrophilicity and increases the strength of the boards by removing the negative effects of water soluble carbohydrates, hemicellulose and lignin on the hydration speed. Also according to the researches by Del Menezzi et al. (2007), adding catalysts to water and cement mixture can increase the hydration speed of the cement paste by increasing compatibility between wood and lignocellulosic materials and cement hydration process.Materials and methods: The used materials in this research include bagasse, Portland cement type II and MgCl2. In this research, by using Response Surface Methodology (RSM), the effect of water-leaching treatment and MgCl2 additive content was examined on modulus of rupture (MOR), internal bonding (IB) strength, water absorption (WA) and thickness swelling (TS) of bagasse-based CBPB. Quadratic models based on Central Composite Face design (CCF) were developed to correlate the variables including water-leaching treatment (X1) and additive content (X2) with the dependent variables including MOR, IB, WA and TS.Findings: Analysis of variance (ANOVA) showed that hot water-leaching treatment improved better the physical and mechanical properties. Also, the optimal condition for improving physical and mechanical properties using hot water-leaching treatment was to use 4.5% MgCl2 additive. In this condition, MOR, IB, WA and TS were 9 N/mm2, 0.3 N/mm2, 17.68% and 1.6%, respectively.Conclusions: Due to its significance in the statistical analysis, the model presented by Response Surface Methodology provided a suitable and significant estimate to determine the application of the variables. According to the statistical analysis, the effect of water-leaching treatment and additive content was significant on the physical and mechanical properties at the level of confidence 99%.