Journal of Wood and Forest Science and Technology
Year:2015 | Volume:22 | Issue:2|Papers Count:12

This study was carried out to investigate the effect of using precipitated calcium carbonate (PCC) filler on properties of printing and writing paper.Background and objectives: Todays, the pulp and paper industries increasingly are growing and developing, and the use of non-fiber additives in papermaking seems necessary. Fillers are a important part of these additives in terms of weight. Common consumption dose of filler in papermaking varied from 3 to 30 percentages. Fillers are insoluble solid particles that added to papermaking suspension to develop the optical properties of paper and also reduce costs. Clay, calcium carbonate, titanium dioxide, talc, and silica are common fillers for papermaking. Antonius et al., (2008) claimed that PCC properties affect the flocculent amount, flocs structure, and finally on the deflocculating and flocs strength. They also published a paper (2010) which described the flocculation of PCC by bridging mechanism using polyelectrolyte polymers with high molecular weight and medium charge density. Their results showed that obtained correlations, effects of flocculent dosage; structure of polymer and flocs affects the flocs kinetics.Materials and methods: PCC filler in 20%, 30%, and 40% consumption levels was added to the fiber suspension prepared by mixing Wood-Free pulp with CMP pulp (30:70 ratio), in order to improve the optical properties and also diminish the used fiber amount which is more expensive and costly constituent part of paper. For improving the filler retention in paper, high molecular weight and high charge density cationic polyacrylamide (C-PAM) polymer was used as retention-aids.were improved by increasing the filler amount in paper, but on the other hand the other strength indices reduced, except tear index which approximately remained without change.Conclusion: In present study, by increasing in PCC usage in paper, ash and bulk of papers raised, while the air resistance, tensile and Burst strengths decreased, which is probably because of reducing bonding area between fibers for presence of fillers among them and also lack of their uniform distribution in paper. Since fillers aren’t able to make bonds with fibers, as a result the tensile and burst strengths of paper reduced due to restricted and weaken fiber bonds, non-suitable formation and lack of stress distribution, consequently. The higher brightness and opacity was observed in papers with PCC filler against those haven’t, which is due to presence of PCC particles among the fibers in paper structure. So that, by adding PCC in paper, though pores in paper with contain PCC enhances, but these papers have higher reflection coefficient in comparison with control papers.

Background and objectives: The purpose of this study was to assess existing roads standards by road inventory and using the results to schedule maintenance operation.Materials and methods: To do this a part of the road network from Kaleibarchay watershed in Arasbaran region was inventoried, and cross sectional components were measured and compared to standard ones. Culverts and bridges along the road were also investigated. Road components, problems of surfacing and slope stability were analyzed quantitative and qualitatively.Results: The results showed that there were significant differences between existing parameters and standard ones and the exceptions were side ditch depth and roadbed. The results of culverts and bridges assessment showed that the road segment only had one culvert. According to the results cross-slope has the highest consistency with standard values. 25.19% of the road length was without any sign of surfacing problems. Among surfacing problems rutting has the highest abundance and cut slope had more stability problems than fill slope.Conclusion: The results of this research can be used in maintenance operation for studied road and also as a model to study and collect required inventory data.

Background and objectives: Pulp and paper industries have provided great research opportunities to control systems. Among different methods, partial least square (PLS) regression is a common software modeling used where the variables are numerous and collinear in industrial applications. Broderick et.al. (1995, 1996), Grage (2004), Nordstrom et.al. (2005), and Ortiz-Cordova et.al. (2006) have used this method successfully using experimental or real pulp and paper industry data. Mazandaran pulp and paper industry as the largest paper manufacturer in Iran and the largest wood-based paper manufacturer in the Middle East suffers from some process control problems to reach acceptable newsprint quality for it has the variable fluctuations in production line. The objective of this study was to investigate the relationships between 56 process variables of stock preparation, and 17 newsprint quality properties in Mazandaran Wood and Paper Industries (MWPI) and to develop predictive models.Materials and methods: After preparation of suitable data series considering the time needed for pulp to paper, the relations between process variables and newsprint properties were determined using partial least square regression (PLS) and SAS and SPSS software. After model development, Split-sample cross validation was done to calculate the best number of vectors. Variables Importance for Projections (VIP) statistic was used to determine the importance of independent variables in PLS model and to summarize it.Results: Developing PLS model, 8 calculated latent vectors could categorize and relate variables and determine more than 60 percent of newsprint properties changes. The first vector as the most important factor, determined changes of 7 newsprint properties including; Caliper, Bulk, Breaking Length MD, Elongation MD, Burst, Opacity and Air Resistance from some of stock preparation variables including; stock pressure in the third group cleaners, rush to drug speed, stock save-all flow, output of second fan pump, head-box slice opening degree, white water chamber valve. The majority of these process variables influence on fibers bonding quality in newsprint paper.Conclusion: Mazandaran pulp and paper industry as one of the largest and most complex manufacturing units in Iran confronts some production alternations. Nevertheless, huge amount of process data is being measured and recorded all day and night in different parts of this complex. Therefore, using PLS model and real data of a part of factory, this research was done and could relate stock preparation variables to final newsprint properties among many variables by 8 calculated latent vectors. Determination of newsprint properties changes from defined stock preparation variables among many of them is quite beneficial and facilitates better and more precise control in the factory.

Background and objectives: Stomata morphology as a taxonomic standard has been used for many years to determine different spices in a genus. This research has been done to identify the different types of stomata and determine its position relative to the epidermal cells of the genus birch (Betula spp.). Also the importance of these morphological characteristics especially stomata type has been studied to separate different species in a genus with the aiming supporting existence theory of different species of the genus Betula spp in Iran and quantitative and qualitative parameters has been investigated in relating with stomata and along cells decor in 3 different population.Materials and methods: Three sites in the forests of birch trees including Siahmarzkoo, Sangde and Shahrestanak has been selected. In every habitat, leaves were collected from four geographical base from outer of crown from 10 trees with minimum 100 meters distance of each other. The photos were taken by light (×10 and ×40) and electron microscopy and morphological traits of stomata were measured. Nested variance test were used for meaningful survey and differences between stomata quantitative in different populations and diversity between and within populations of the three sites were investigated.Results: Significant differences in nested layout analysis were calculated between large and small stomata length, large stomata width, its area and no significant differences between small stomata width and densities in different populations. The highest and lowest stomata area related to Siahmarzkoo and Sangde respectvely. Correlation between stomata traits and geographical habitat characteristics showed that length, width and area of the stomata decreased by increasing height above sea level and will increase by increasing latitude and longitude. 70 percent match between stomata characteristics and ecological conditions of the habitats were showed by Detection analysis. Two types of stomata including paracytic and anomocytic were identified in this genus with paracytic dominant. One similar type of stomata was recognized for three sites in terms of position of stomata in comparison with epidermal cells and in this type, stomata located over than epidermal cells.Conclusion: Birch is more seen in the mountains compared to other species so it is tolerant in height difficult climatic conditions. Stomata cannot be used as a marker for predicting birch species in Iran because all studied parameters has been showed the high influence of environmental conditions.

Background and Objectives: Fines and mineral fillers retain in paper with mechanically stick and colloidal aggregation mechanisms. Chemical additive used to retain the fines colloidal particles, are non functional additives (process aids material). These materials indirectly with improved paper formation and increases fines durability and mineral filler material, has positive impact on the properties of the produced paper. The most important synthetic polymers structures that are used to increase the durability, can be poly acryl amide, polyamines, polyethylene, polyethylene oxide amines. Retention systems species are include single cationic polymer, single anionic polymer with Aluminum ions, dual polymer systems, micro-particle systems and network systems. In dual polymer systems, use two poly electrolytes, one is cationic polymer with high cationic charge density and low molecular weight and the other is anionic polymer with high molecular weight and low anionic charge density. In this research, the effect of dual retention system, poly ethylene imin plus anionic poly acryl amid on the newspaper properties and the results were compared with single cationic poly acryl amide system.Materials and Methods: The fibers combination used in this study, is the same compound used in Mazandaran pulp and paper industry, include 83 percent CMP chemical- mechanical pulp produced in Mazandaran pulp and paper and 17 percent of import bleached kraft long-fiber pulp and 20 percent by weight of pulp and paper in this study is used precipitated calcium carbonate filler. Also the combination of anionic poly acryl amide and poly ethylene imin polymers and in three levels: low, medium, and high were used and its effect on pulp dewatering properties, filler retention and also handsheet newspaper strength, structural and optical properties of durability, resistance and optical paper were examined and compared to control samples, single retention aid.Results: According to the results and compared with a single cationic poly acryl amid system, using dual retention system, poly ethylene imin plus anionic poly acryl amid Increases pulp freeness, fines and filler retention, paper formation index and porosity. In terms of paper strength properties, in low consumption levels of retention aid, newspaper strength properties specially tensile and tear index of handsheets treatments that dual retention system, poly ethylen imin plus anionic poly acryl amid was lower(significant difference) because of poorer formation quality and having more filler materials, compared to the control treatment but with the increase in consumption, especially in the high consumption rate of retention aid were no significant differences between the tensile and burst index between compared treatments. In terms of optical properties, in low consumption levels of dual retention aid system, poly ethylen imin plus anionic poly acryl amid compared to control treatment, found no significant difference in handsheet absorption coefficient and light scattering but with increasing in dual retention aid system consumption, hand sheets absorption coefficients and light scattering sheets, compared with the control treatment was significantly reduced.Conclusion: in comparison with control samples, the applying of dual retention system, have significant effects on newsprint pulp and paper properties and the positive or negative effects of dual retention system depends on level of chemical consumption.

Background and objectives: Snow damage is a significant and serious problem in managing of mountain forests. Extensive researches on snow damage have not been down in Iranian natural forests. The main objective of this was to estimation of frequency and intensity of snow damages on trees in relation with physiographical characteristics (slope and aspect) in Asale-Nav mountain forests in Guilan province.Material and methods: Frequency of different types of snow damages on trees were studied after heavy and early snowfall in 11 Dec. 2011 in altitude of 1,350 to 1,650 m a.s.l. of Asalem-Nav forests. Frequency of damaged trees and snow damage types were collected through circular sample plots with each area 1000 m2 in regular distances 100 m from each other. The frequency of snow damage types in slopes (less and more than 50%) and ground aspects (northern and southern) were compared by non-parametric chi-square tests.Results: About 14% of trees were damaged due to snowfall. The frequency of damaged trees in slopes > 50% (18.2%) was significantly (P<0.01) more than slopes < 50% (10.5%). The frequency of damaged trees in the northern aspect (17.6%) was also significantly (P < 0.01) more than southern aspect (10.3%). The frequency of crown damage, stem breakage and bent over in slopes >50% were more than the slopes <50%. Also the frequency of bending, stem breakage and bent over trees in the northern aspect were more than the southern aspect. The frequency of snow damage in Fagus orientalis, dominated tree in the study area, in the slopes > 50% was more than slopes < 50% (P<0.01). The snow damage on tree species of Carpinus betulus, Acer velutinum and Acer cappadocicum was more in the northern slope, while the snow damage on tree species of Quercus castaneifolia and Alnus subcordata was more in the southern slope. The most frequency of snow damage was observed in trees DBH < 30 cm. The slenderness coefficient of damaged trees was greater than safe trees in all tree species.Conclusion: The snow damage on Asalem-Nav valuable stands is considerable. The frequency and intensity of snow damage on trees was related with physiographical characteristics and structure of these forests. In order to strengthening of trees against to the snow damage needs to adequate silvicultural operation in mountain forests.

Background and objectives: Paper plays an important role in supplying human requirements. Sanitary papers have special place between various types of papers. One the most important requirement of sanitary papers is to be sterilized. On the other hand, in this type of paper, improving of antibacterial property is too important that it is neglected in paper industries of our country. In this study silver nano particles were used to improve the antibacterial properties of paper.Materials and methods: This material was used at two levels of concentration (25 ppm and 100 ppm in pulp suspension). All hand-sheet’s antibacterial properties were evaluated using the OD method. In this method Escherichia coli bacteria and Bacillus subtilis bacteria were used. theses tow bacteria are representative of Grampositive and Gram-negative bacteria respectively.Results: handsheet treated with nanosilver at concentration of 100 ppm decreased the growth of Escherichia coli bacteria by about 98% while; handsheet treated with nanosilver at concentration of 25 ppm just decreased the growth of Escherichia coli bacteria by about 63%. So, antibacterial properties of paper increased with increasing of nanosilver retention. The results showed that using nanosilver also decreased the growth of Bacillus subtilis bacteria. Using nanosilver at concentrations of 25ppm and 100 ppm decreased the growth of Escherichia coli bacteria by about 49% and 55% respectively.Conclusion: Results have shown that silver nanoparticles at the same consumption levels had a larger reduction in growth of E. coli in comparison to Bacillus. Also, all concentration levels of nano silver reduced the growth of both bacteria, but low consumption value of nano silver (25 ppm) reduced the growth of both bacteria significantly that is very important in terms of its safety and health. Finally, according to the results, the use of nano silver didn’t show conventional negative effects of additives and fillers on reducing of some physical, mechanical and optical properties. Comparing the results of physical, mechanical and optical properties of treated paper and control one showed that using nanosilver as antibacterial agent didn’t result in negative side effect (that could be seen in using conventional antibacterial additives).

Background and objectives: Estimation of forest carbon stocks essentially needs accurate estimation of biomass. During last decade, many regression models have been developed, while biomass estimation of the small diameter trees as a missing part of forest measurements is highly significant. The main objective of this study is to develop allometric equations for easy, non-destructive, low cost and fast estimation of different tree components biomass including stem, branch, leaf, bark and total biomass of small diameter trees of Carpinus betulus, Fagus orientalis, and Parrotio persica.Materials and methods: From each species, 9 intact trees with 2-8 cm diameter were randomly selected and collar diameter, diameter at breast height, stem diameter at the crown bottom, crown width, and height were measured. Then the trees were felled down and different parts were weighted. One sample from each part of each individual was transferred to the lab and dried in oven until reaching a constant weight (48 hours in 70 C for leaves and 72 hours in 80 C for other woody parts) and the percentage of dry weight was calculated. The most appropriate equations for estimating the different parts of the trees biomass were selected using power regression model. For selecting these equations, R2, standard error and regression analyses of variance were used.Results: The results showed that among the various independent variables, diameter at breast height is the most appropriate estimator in the term of determination coefficient (R2) for estimating woody parts biomass of small diameter trees in all studied species. Highest determination coefficients were observed for stem biomass of Carpinus betulus (0.928), stem biomass of Fagus orientalis (0.934) and total aboveground biomass of Parrotio persica (0.936).Conclusion: Amongst the different standing tree parameters, diameter at breast height a lone can be used to derive reliable allometric equations. In general, establishing allometric equations for woody parts of small diameter trees with high precision is achievable. But, for non-woody parts, highly precise equation is not derivable; this may be a result of high variability of leaf biomass in younger age due to variable environmental conditions such as available light.

Background and objectives: Cotton fibres are one of important non-wood and industrial cellulosic resources in the world. Cotton linters are produced as a byproduct accompanies with cotton fibers which is used as a significant cellulosic sources in paper industry for producing durable paper. Refining is the most common method used for improvement of bonding potential in fibers. The interfiber bonds in high alpha cellulose pulps such as bleached cotton linter can be only slightly developed by action of refining. Layer-by-Layer self-assembly technique is a novel method in nanotechnology for modification of the surface properties of solid materials. Among these material cellulosic fibers can undergo surface changes by formation of polyelectrolyte multi-layers (PEM) using layer-by-layer method. Therefore, In order to modify the surface properties of linter fibers and develop the fiber-to-fiber bonds, the Layer-by-Layer self-assembly method (LbL), a novel technique in nanotechnology, was used in present research.Materials and methods: Medium molecular weight chitosan were used to form cationic layers while Nano fibrillated cellulose (NFC) were used to form anionic layers. The experiments for making 1 to 3 alternate cationic and anionic layers were performed using linter pulp suspension at 0.5 % consistency, NaCl ionic strength of 0.01 M, different levels of pH and stirring at layer deposition time of 15 min. Adsorption of polymer on the surface of linter fibers was analyzed by electrolyte titration. Standard hand sheets were made from samples of the modified linter fibers and their physical and strength properties were determined. Changes in inter-fiber bond ability due to polymer depositions were evaluated by field emission scanning electron microscopy (FESEM).Results: The results showed, apparent density and also bonding ability was improved significantly at second layer, whereas the apparent density and tensile index of the sheet was increased by 10% and 76% compared to untreated fibers at second layer. Bonding ability of fibers was improved by polyelectrolyte multilayering (PEM) on the surface of cotton linter fibers which was visualized by Field Emission Scanning Electron Microscopy (FESEM).Conclusion: Layer-by-layer assembly is a versatile, simple, and easy to use technique that is showed promising results in improving the strength of the cotton linter fiber network. Accordingly, physical and strength properties of the papers made of modified linter fibers were significantly improved because of the increased electrostatic attraction between polycation and anionic existed sites on the fiber surface.

Background and objectives: Accuracy in volume estimation of industrial as well as firewood of cut trees, which are the base of stumpage and toll collection calculation, is very important in forestry plans. This investigation aims to evaluate the 3P and traditional renewal methods of hornbeam trees in comparison to the actual volume of cut hornbeam trees in Bahram-Nia Forestry Plan.Materials and methods: Therefore, 282 trees of hornbeam species were selected from official cut permission of the year 2011 of the mentioned forestry plan. At first the volume of selected trees were calculated using the traditional hundred percent volume renewal methods. Then the actual industrial wood, firewood and total volume of all hornbeam trees was calculated according to the 3P prescription. Volume estimation of hornbeam trees was done through 3P volume renewal method (in 5 replications). The results of these two methods were compared to the actual volume of cut trees.Results: The results showed that there was a significant difference between the industrial wood, firewood and total volume in traditional method with the actual tree volume. Under estimation of industrial wood volume was due to Indiscrimination of decayed parts of trees, and over estimation firewood volume was due to calculating it according to difference of total tree volume (volume table) and industrial volume. Consequently, over estimation of total tree volume in traditional method was happen relatively. The difference of estimated volume between 3P methods with the actual cut trees volume was 0.4 to 6.3 percent that is not statistically significant. Generally the total volume calculated by 3P method was less than (23.1 to 30 percent) the total volume calculated by traditional method.Conclusion: Regarding to the result of this study, the 3P method is suggested for volume renewal of cut trees in reclamation areas due to higher accuracy, lower consumption of labor proficiency and hence lower costs in comparison to the traditional hundred percent method.

Background and objectives: This research was performed with the aim of using anthraquinone (AQ) as catalyst in order to improve the properties of the pulp from hornbeam, neutral sulfite semi chemical (NSSC) pulping. Various studies about the effect of AQ on the chemical pulps such as soda and kraft has been approved an improving of delignification and yield, and reducing of kappa no. and reject content.Materials and methods: The NSSC pulping of Hornbeam was carried out to approach three screen yield levels of 55, 60 and 65%. The cooking conditions were chosen as: temperature (175˚C), time (variable), total chemicals 14% and anthraquinone 0.1% (based on o.d. wood chips) to achieve the mentioned screen yields. In all cooking trials, sodium sulfite to sodium bicarbonate weight ratio was constant equal to 4.5:1, and cooking liquor to wood ratio was 4 to1, respectively.Results: The results indicated that anthraquinone decreased the cooking time (5 to 10 min.), pulp reject (1.8 to 0.3%), and kappa number (3 to 4 units) due to its better selectivity. NSSC- AQ pulps showed less energy needed for refining compared to the control pulp. Also, all the strength indices average of the hand sheets including burst: 22.4%, tear: 7.1%, and tensile: 20.4%; ring crush test (RCT): 16.2%, and corrugated medium test (CMT): 8.3% were increased significantly (P£0.05) by using anthraquinone in pulping. Regarding optical properties, the brightness of hand sheets with screen yield of 65, 60, and 55% were increased significantly 76.5, 47.5, and 16.4%, respectively by adding AQ in the cooking stage. Also, average of paper opacity increased slightly at 0.4%, but the change was not significant.Conclusion: It could be said that the utilization of 0.1% AQ brought to improvement of delignification, less refining energy consumption, and strength and optical properties of NSSC pulp made from hornbeam. In addition, AQ could be able to maintain its selectivity in weak alkaline conditions (lower pH) of NSSC process. These positive results are very important for the production of corrugated board which is used frequently in npackaging idustry.

Background and objectives: The area and intensity of forest fires is strongly dependent upon the type of fuels and its spatial variability across the Landscape. It is very important to develop accurate ways to assess fuel characteristics and predict the probability of fires occurring in heterogeneous landscapes for fire prevention and management. The objectives of this research were to build local scale fuel type map and simulate their fire behavior.Materials and methods: The spatial extent of the different fuel types of Toshi forest in Siahkal characterized by heterogeneous vegetation and topography was determined using a field survey. Four different fuel types (grass, grass-shrub, natural forest and plantation) were analyzed. The fuel types were developed by field sampling and the collected data was inserted in the FARSITE simulator to modeling potential wildfire spread and behavior.Results: The simulation results revealed that the fuel type for the shrublands and natural forests demonstrated the longest flame length, the highest fireline intensity and the greatest heat release per unit area. The fuel type for the grass fields presented the fastest surface rate of spread; and the fuel type for the plantation the lower fire intensity.Conclusion: The fire behavior maps are an end product which can be fully exploited operationally from local fire management authorities without further processing for an effective wildfire management and proactive emergency response.