نشریه علوم و فنون منابع طبیعی
سال ششم شماره 4 (زمستان 1390)

For roundwood loading in the northern ern forests of Iran, different kinds of machines are used namely G.M.S, loader- grapple, revolving crane and so on. Work study and time measurement were used to compare two roundwood loading machines of G.M.S and loader grapple. Collection of the needed data to estimate the production rate and cost for every cubic meter in loading operations in Golband station was done by harmonizing the work stages (load-free going time, taking and lifting, return time, putting and arranging) of these two machines, then the time measurement of two machines was handled in four components and the obtained results are as follows: Pure spent times for each one-time loading component of G.M.S and loader- grapple show that the total pure spent time in G.M.S is 5.28 times as much as that of loader-grapple. The production rate of loader-grapple machine using pure time without including delay time is 69.29 meter cube per hour (mcph) and using total time with including delay time is 43.43 mcph while the former of G.M.S is 11.55 mcph and the latter of G.M.S is 9.65 mcph in a way that the amount of production of loadergrapple without including delay time is 5.99 times as much as that of G.M.S and with including delay time it is 4.50 times as much as that of G.M.S. The results also show that in G.M.S loading system despite the higher cost per hour, there was lower hour production than loading system of loader-grapple .Therefore, loading system of loader-grapple not only shows higher hour production, but also shows lower cost per hour than G.M.S loading system.

Urban forest is quite significant in reducing negative effects of Civilization and preserving the ecological balance of urbon ecological system. With the goal of estimating carbon storage in the Ash affrostration, transect sampling of the region was conducted. Five samples of average diameter of each diameter class were selected. After determining the overall weight of different parts of a tree, to measure the dry weight as well as to determine the amount of biomass, different parts of that tree were transformed to a kiln. The quantity of ash was taken away from biomass and then the amount of organic sequestrated carbon was measured. To determine the physical and chemical characteristic of the soil, 12 samples were collected from 0-30 and 30-600 cm soil depths. Research results show that the amount of annual biomass and carbon storage was estimated respectively 526 and 464 Kilograms per hectare. The results of Duncan test showed that there was significant difference between the amounts of carbon storage in different diameter classes. Considering the characteristic of the soil, the percent of Nitrogen and organic carbon showed the maximal correlation with the amount of biomass.

The aim of this design is to introduce the most successful exotic species for forest Plantation Projects. The trial was conducted in 1992 at middle altitude of Neka forest in Mazandaran Province of I. R. Iran (North Forests), under compeletly Randomized Block with 3 replicates and 13 treatments (Species and provenances of conifers). The treatments consisted of nine species, including: (Pseudotsuga menzeisii (M.) F., Pinus sylvestris L., Abies nordmaniana (Stev) Spach, Abies bornmulleriana Matf, pinus nigra Arn.ssp austriaca, Larix deciduas Mill, Picea abies (L.) Karst, Cedrus deodara (D.Don) G.Don and Pinus ponderosa Laws. The species growth characteristics were measured after 16 years (1993-2008), including survival, total height, collar diameter, breast height diameter and quality. Physical and chemical properties of soil were determined and climate characteristics were identified. The statistical analysis showed that there were significant differences between the species in relation to their qualitative and quantitave parameters. The results showed that Pinus sylvestris provenances (Yugoslavia and Armenia origins) were the most promising treatments and pinus nigra Arn.ssp austriaca, Pinus ponderosa Laws and Picea abies (L.) Karst (Kelardasht and Ladjim origins) were the second promising treatments, respectively.

Water cycle has an important role in relation to soil, vegetation and environment. This cycle is one of important ecological phenomena in natural biocenose, especially in forest ecosystems. Canopy interception loss (CIL), Throughfall (TF) and Stemflow (SF) are accounted as a large proportion of the water cycle in forest ecosystems. The study was performed from October 2009 to October 2010. Interception, Throughfall and Stemflow were conducted in a natural stand of hyrcanian beech (Fagus orientalis Lipsky) in Parcel 701 Shenrood forests of Siyahkal. Total precipitation (GR) was collected using four manual collectors in an open area approximately 150 m apart from the study site. Sixty TF manual were randomly placed beneath the beech canopies and SF was collected from twenty cylindrical beech trees and symmetry crown, with different diameters by means of the spiral type SF collection collars installed at diameter breast height on trees. Most appropriate models for CIL, TF and SF forecast were obtained by using regression and beech characteristics. The amount of GR estimation on was 1497 mm allocated to SF, TF and CIL for beech stand, 1.2 %, 47.5 % and 51.3 %. When the total precipitation increased, SF, TF and CIL increased. The study showed that the Pearson correlation coefficient between these parameters shows significant correlation (99%). When tree diameters inereased SF reduced and CIL increased.

In this research, neutral sulfite semi-chemical (NSSC) pulping of mazandaran province canola stalks was studied. At first the anatomic and chemical properties of canola stalke fiber were measured. The pulping conditions were as follows: Pulping temperature on one level (170 oC), pulping time of 3 levels (20, 30 and 40 minutes) and sodium sulfite charge on 3 levels (10, 15, and 20%). In all cooks, the proportion of Na2So3 to Na2Co3 was 2 to 1 The out put after cooking varied from 61 to 82 %. Regarding the optimum freeness for the NSSC process, pulp was refined to obtain 400±25 CSF. From each pulps sample, 127 g/m2 handsheets were prepared. Then, using TAPPI standard methods, strength properties of handsheets were studied. The statistical analysis of strength indexes showed that the pulping condition with 20% sodium sulfite and cooking for 30 minutes the optimum condition of (NSSC) pulping for corrugated medium production. The paper properties including corrugated medium test, ring crush test, tensile strength index, tear strength index and burst strength index were 232 KN/m, 1.96 KN/m, 35.56 N.m/g, 6.19 mN.m2/g and 2.29 Kpa.m2/g respectively.

In this research, 15 m3 of poplar (Populus nigra) lumber with 7.5 cm thickness cut down from cultivated grounds of Shirvan Town in North Khorasan province was dried with kiln-drying schedules T5-D2 (Forest Product Laboratory), T5- D3 and T7-D3 in semi-automatic kiln with final moisture content of 8±2%. Then the effect of kiln-drying schedules on warp and surface checks of the lumber was evaluated in order to reach the least time for drying for having the desired wood quality. Primary dry bulb temperature of each three schedules were adjusted at 49,49,and 54°C and the final dry bulb temperatures was adjusted at 71°C. The defect of warp, bow and surface checks in the lumbers were measured before and after the drying process in each stage. In order to analyse the lumber defects for estimating the best schedule the quality control graph was used. Results of study showed that the desired schedule was drying of poplar lumbers by using T5-D2 and T5-D3 schedules. However, the first schedule (T5-D2) showed better drying characteristics (humidity gradient, quality and quantity of lumbers than the other schedules).

In this research, we try to study how warehouse product asset in Asalem particle board factory is controlled. Considering that, the factory is managed traditionally and there isn’t any model for setting producted particle board in this warehouse .we propose EPQ model (Economic Production Quantity) after evaluating more suitable models. the goal in this model is predicting the average of stored sheet numbers annually in relation to warehouse capacity .After gaining necessary data for the model that is statistically related to accountancy and warehouse and replacing it in mentioned formulas. The necessary amounts are obtained measuring of Q* and Imax is necessary and should be considered in the selling of stable and variable costs in 1388, derived from accountancy unit. Additionally the amount of demand (D) and production(P) were measured with linear regression and level growth method, respectively. With placing the obtained numbers in the mentioned formulas the average yearly stored sheet is predicted and a suitable pattern is shown while considering the predicted sheet numbers and warehouse capacity for setting the production. The result shows that the best model is the presented so that model, we can use the warehouse space more properly.

In this research, deinked pulp was prepared and chosen randomly from the Latif paper co(Tissue Mill). The pulps were treated with cellulase.The influence of enzymatic treatment on pulp and paper properties (freeness, tensile strength, burst strength, tear strength and folding endurance) was investigated. Two different conditions were applied:cellulase dosage (0.1 and 0.3% based on dry weight of pulp) and treatment time (30, 60 and 120 minutes). In these treatments, temperature of treatment was adjusted at 30ºC, pulp consistency (3%) and PH (5)was fixed. The results of this research showed that enzymatic treatment improved mechanical properties of handsheets were obtained from treated pulps.Furthermore, maximum strengths were observed in treated pulps with enzyme dosage 0.3% in 60 minutes. The lowest freeness(ºSR) was observed in treated pulps with enzyme dosage 0.3% in 120 minutes.

The investigation of the possibility of utilizing AKD sizing agent and its effectiveness on paper properties in chemi-mechanical writing paper are the two goals in this technical study. For this reason, the results of producing writing paper with fixed combination pulps of CMP (80%) and BKP (20%) with AKD were investigated. Then, after measuring optical and strength properties, Anova and Duncan tests were utilized for assessing their significant effect and the comparison of the means respectively. The results showed that additing AKD decreased the rate of water absorption and paper strength (exception of air resistance) and improved optical properties.

In this study, the effect of creating the scarf joint and finger joint on acoustical properties of the specimens of beech wood is investigated. 14 Samples were selected according to ISO 3129 standard and bending vibration in free beams and longitudinal vibration tests were performed on them. The results showed that creating scarf joint increases the damping factor and decreases the acoustical conversion efficiency; While creating this type of joint does not have significant impact on the acoustical coefficient. The results also showed that creating finger joint, in addition to decreasing acoustical converting efficiency decreased the acoustical coefficient. In general we can conclude that if it is necessary to use the joints in acoustical perfomances, the scarf joint has fewer negative effects on acoustical properties than finger joint.

Some tests were carried out to determine the mechanical behavior of dowel joint made from Hornbeam (Carpinus betulos) dowel in comparison to compressed wood of Paulownia and Populus dowels (30% compressed). The diameter and length of dowel holes were 10 and 25 mm, respectively. Distances between dowels were fixe at 10, 12 and 15 mm. Dowels were glued and then inserted in holes. In this study, mechanical tests were given to measure withdrawal, shear loads and bending moment. T form joints were made from dowels and blocks of Beech (Fagus oreintalis). Results showed that types of dowels affect withdrawal load. So, significantly that compressed Palowlonia dowels showed more resistance than others. Shear load results showed that dowels type and distances between dowels were strongly effective. Hornbeam dowels had the highest shear loads than others. In adition, if distances between dowels were 10 mm, then shear loads would have the highest values. However, bending moment results showed that, if distances between dowels were 15 mm, then bending moment would have the highest values. Dowels made from Hornbeam had the highest values of bending moment.

Risk assessment approach is one of the essential bases in establishing and using management systems in different organizations. Establishing a kind of complex managerial system in sanitation, security and environmental organizations would help them to be able to have processes to prohibit errors. ARYASASOL Petrochemistry is the biggest unit producing Olphyn gas in Iran which is placed in Pars economic area. The present study is conducted in ASALLOYEH, the production unit of heavy and moderate petrochemistry complex, ARYASASOL, to indentify its environmental aspects and introducing practical alternatives to decrease or even to omitt the negative environmental effects using the analysis methods in breaking states besides considering their effects on environment. This method is a qualitative one which is used as the best possible method in developing the process. Its objective is to recognize and to classify the environmental aspects beforehand which leads to appropriate results during the life circle. Therefore these aspects were first assessed and assigned the prior risk number and the risk degree also was calculated through excess distribution method. Doing the statistical calculations it was shown that some environmental aspects holding the risk priority number more than 19.5 are riskier than others. The obtained results showed that 24.8% of the environmental aspects were at low risk; 21.46% stand in average and 14.12% were high meanwhile 39.54% were considered beyond high levels that for the last two we should apply reforming and risk managerial processes.