جستجوی مقالات مرتبط با کلیدواژه « راش » در نشریات گروه « صنایع چوب و کاغذ »

In this study, the effect of nano-copper particles on heat transfer in the cycle, press and mechanical properties of boards of five layers was studied .Two species Iranian beech and Populus deltoides and nano-copper particles at four levels of (0, 5, 10 and 15%) of the time, Press (4, 5 and 6 minutes) as the variable factors were considered in this study. Mechanical strength of plywood (including MOR and MOE, SH) were measured.Results indicate that mechanical strength of plywood (including MOR and MOE, SH) after a primary increase from 4 to 5 minutes of press time decreased after 6 minutes of press time. Increasing intake soluble nano copper from 0 to 10% and cause an improved the in MOR and MOE . So it can be attributed to reason increasing speed of heat transfer and glue absorption cause an improved the boards. But with increasing consumption 15% reduction in the features.In all the the mechanical strength of boards, Species of beech very good performance compared to Populus deltoids that so it can be attributed to internal bond improvement.

Recognition of the natural durability of wood and industrial species of each country is essential and Iran is no exception to this rule because of valuable commercial species. Generally, the natural durability of wood is determined in the laboratory and field by measuring the decay resistance of wood according to EN 113 and EN 252. However, Meyer- Veltrup et al. proposed a new method entitled "resistance model" to estimate the natural durability with more accuracy which can be generalized to conditions without soil contact. In this model, two factors namely inherent resistance and wetting ability are used. Beech (Fagus orientalis) was selected as one of the most important commercial species in Hyrcanian forests to study its natural durability. The results showed F. orientalis heartwood and sapwood were less durable and non-durable (DC 4–5). Water immersion after 1 and 24 hours was highest for sapwood followed by heartwood. Based on the MLF index, 61 % of sapwood was attributed to the white fungus (T. versicolor) as well and the lowest MLF was caused by sapwood and heartwood by the H. Fragiforme. 43.5 % of MLF on beech wood is caused by terrestrial organisms (TMC). Based on the resistance model, the first signs of decay were observed after 312 and 294 days.

This study investigated the bending and shear strength of hybrid cross-laminated timber (CLT) manufactured from beech (Fagus orientalis) and poplar (Populus deltoides) wood using experimental and finite element methods. The CLT panels were manufactured at various span to depth ratios 6, 10, 15, 20 and 25 with width of 30 cm and thickness of 2 cm in both major and minor directions. Then, the bending and shear strength of CLTs were measured using three-point bending test according to ASTM test methods. The results indicated that with the increase of span to depth ratio of the beam from 6 to 25, the averages modulus of elasticity (MOE) and modulus of rupture (MOR) values were increased in both major and minor directions. On the contrary, the averages shear modulus ( ) values of specimens in both directions were decreased.  Moreover, the results of finite elements showed that the amounts of stress distributions and their locations were different in major and minor directions of the beam. In the major direction, the surface layers were primarily contributed load-carrying capacity of CLT panels, while in the minor direction the middle layer played the most significant role for load-carrying capacity. In this research, it was resulted that specimens with span to depth ratio greater than 15 based on ASTM D198 can be used for calculating MOE and MOR of CLT panels. Furthermore, due to existence of lower difference than 10% between experimental and numerical results, modules of elasticity of CLTs were predictable according to finite element method

There are various mechanical, chemical and thermal methods to improve the properties of wood which Their purpose is to block and reduce the reactivity of hydroxyl groups of cell wall polymers. The aim of this study is to modify the properties of Iranian beech wood ( Fagus orientalis L) via the passage of electricity.Three substances of water, salt solution in two levels and silver nanoparticles in two levels have been used to transfer electricity in wood. The experimental design was a factorial test on the basis of a completely randomized design to analyze the data obtained from the measurement of physical and mechanical properties. The results showed that the passage of electricity improved all the physical and mechanical properties of beech wood. Electric current passing via a 20% salt solution and 200ppm silver nanoparticles increased the Moduli of Rapture of beech wood respectively 25% and 29%. Electric current passing by both cause the Moduli of elasticity became more than fourfold And Anti-Swelling efficiency Based on the volume of beech wood obtained respectively 30% and 35%

In this study, the effect of silica nanoparticles and heat treatment of beech (Fagus orientalis),walnut (Juglans regia) and spruce (Picea abies) wood species on adhesion strength, drop contact angle and water absorption of clear coating lacquer were studied. For this purpose, samples with 8% moisture and 200 × 100 × 20 mm were prepared. The wood samples were heat treated in oven at different temperatures of 160 and 180 °C for 3 hours. After finishing the treatment, the surface finish of the specimens was 120 and 180, respectively. Transparent lacquer folders containing 0, 0.5, 1 and 1.5% silica nanoparticles were used to cover the samples. The results showed that heat treatment increased the drop contact angle and the adhesion strength of the coating and increased the temperature of the drop contact angle treatment and the adhesion strength as well. Thermal treatment at 180 °C with coating containing 1% nano and lowest drop contact angle was observed in control samples. Wood samples treated with walnut at 160 ° C and containing 1% nano coating had the highest adhesion resistance. The water uptake of treated wood samples decreased compared to the untreated samples in all three species and this trend continued with the increase of nanoparticles in the coating so that the walnut control samples had the highest water uptake at 180 °C. and 1% nano coatings were the lowest water absorption in spruce.

Wood heating is the oldest method for reducing of water absorption of wood. Today, electric heating is used to transmit high voltage current through materials using two electrodes. The aim of this study is to investigate the effect of electric shock on the physical and mechanical properties of Iranian beech wood( Fagus orientalis L). Electric shock applied to the wood samples in five different voltage and three different pressures in the reactor. The experimental design was a factorial experiment on the basis of a completely randomized design .The results show that electric shock of beech wood improves all its physical and mechanical properties. The best results obtained at atmospheric pressure and electric current of 600 volt.In this situation, Moduli of elasticity became treble and Moduli of Rapture increased 20% based on control sample. Also obtained 20 % Anti-Swelling efficiency.

The aim of this research was investigating the effect of fiber reinforced polymer (FRP) on the strength of T-shaped wooden joints under tension load. In this regard, T-shaped joints were constructed with beech and poplar species and were reinforced with 1 and 2 layer of carbon and glass fibers reinforced epoxy and vinylester polymers of composite. Joint members were assembled by used of wooden dowels and polyvinyl acetate adhesive and then withdrawal resistance of reinforced joints were studied. Results of variance analysis showed that the independent effect of species of joint members, resin type and number of fiber layers at FRPs was significant at 5% level. Results have indicated that withdrawal resistance of joints constructed with beech species was more than the poplar species. The investigation of the effect of number of layers showed that the withdrawal resistance of the joints reinforced by two layers of carbon and glass fibers was more than one layer. Results of FRPs investigation indicated that use of epoxy matrix in comparison with vinyl ester matrix exhibited better results. In addition, carbon fibers have shown better performance than glass fiber as reinforcing agents. According to the results the best treatment was the joints of beech wood and reinforced by composites with epoxy matrix and reinforced with two layers of carbon fibers.

Fiber Reinforced Polymer (FRP) has become one of the most popular methods in the reinforced, repair and rehabilitation of structure due to its ease of application and the special physical characteristics. Both destructive and nondestructive assessments have been used to test the characteristics and durability of FRP in order to investigate the condition of the structure. The aim of this research was to investigate the structural performance of corner joint reinforced with fiber reinforced polymer (FRP) composite under diagonal tension load. Constructed joints from two wooden species of beech (Fagus orientalis) and fir (Abies alba), were reinforced with reinforced composites of one and two layer of carbon and glass fibers and then they were tested under diagonal tension load. The miter corner joints were made with wooden pin and polyvinyl acetate adhesive. The fibers lay-up was done manually. Epoxy resin was used as a polymeric matrix. Result of investigation indicated that use of beech wood in comparison with fir exhibited better results. In addition, glass fibers have shown better performance than carbon fiber as reinforcing agents.  Inspection of diagonal tension specimens after failure have indicated that using of FRPs on the surfaces of L-shaped miter prevent joint opening, however, failure was occurred at the joint by increasing of load and vertical displacement and the general wood weakness in tension perpendicular to the grain and shear parallel to the grain at dowels site due to stress concentration. Also the results showed that the miter corner joint made with beech species and two layers of glass fibers had the highest stress carrying capacity.

Fagus orientalis is a valuable deciduous tree species mainly distributed in northern of Iran.There is great demand in the market for its log especially for knot-free logs. The classification of roundwood is inextricably linked to the measurement of a particular single wood defect. The appearance, location, and number of defects are important in the quality evaluation of logs and sawn timber, and the most important defects are knots. To evaluate the defects of trees, destructive methods (cutting) and non-destructive methods (CT scans) are used. The purpose of this study was to calculate clear wood by four models and compared to CT- scan. Fifteen stems of oriental beech trees were studied. The Pearson correlation coefficient and the Kolmogorov-Smirnov test have been used to check the normality of the data and the correlation between the parameters. The results show that the detection of CT- scan is high at the organs have a significant difference in the density. The accuracy of detection and evalution is high in the CT-Scan method. The results show that there is a high correlation between all methods of estimating clear wood. The most correlation coefficient was obtained between the fourth model and CT-Scan method(r=0.994) which their clear wood estimation are the same. Among the studied models, the first model (∆r=Ws-Ls) which is based on the external indicator is more suitable for evaluating of the beech clear wood in the log grading process

Dyes release into waste water due to its toxicity for some organisms results in major environmental pollution problems. The activated carbon (AC) is an efficient adsorbent to remove this kind of pollutants from aqueous phase. Hence, in this research activated carbon was prepared from sound and rotted beech wood by chemical activation method and its adsorption capacity for removal of Rhodamine B was assessed. The carbonization and activation steps were performed at single stage with impregnating the substrate by zinc chloride as activating agent and with the ratio of 75, 100 and 125 percent to raw material mass at 400 and 500 ºC. The results showed that with increasing the impregnating agent content, the iodine number of ACs from both woods enhanced. The yield of AC from sound wood decreased with increasing impregnating agent while it was not predictable for AC resulted from rotted wood. Scanning electron microscopic (SEM) studies revealed much morphological changes in the surface of rotted wood-AC in comparison with sound wood -AC after treatment with activating agent. Also, raising the activating temperature from 400 to 500 ºC caused to enhance the iodine number. All prepared ACs performed much efficient in removal of Rhodamine B from aqueous solution. The maximum adsorption of the dye was obtained for ACs prepared under impregnating ratio of 125 and activating temperature of 500 ºC.

Radiography is a method of non-destructive for evaluating the quality of wood construction machinery in order to detect the defects due to natural degradation. The objective of this study was to investigate the assessment of Poplar (Populus deltoides) and beech (Fagus orientalis) wood defects arising from the decaying by using x-ray non-destructive method. In this study, for each of species, uncolored (no coating) and colored samples by acid catalyzed lacquers and nitrocellulose lacquers were used. Decay resistance test based on modified ASTM D1413 standard was performed. The decay process was done in the periods of 1, 2 and 3 months with use of Coriolus versicolor fungus at laboratory condition. After each of these periods, for the decay of the samples, x-ray imaging by using an imaging at the lateral, tangential and radial direction was done. Results of weight loss confirmed the presence of decay in the radiographic images. The results showed that after 1, 2 and 3 months of exposure to fungus, fungal degradation leads to weight loss in the painted and unpainted samples. So that, the weight loss caused by decay in beech was less than poplar samples. As well, the weight loss of unpainted was less than painted samples, which was also statistically significant. The x-ray results of unpainted and painted samples at the cross, tangential and radial directions indicate that decay has a more impact on beech in comparison to poplar wood structure. The study as well showed that the protective layer has partly a barrier for decay destruction in these samples.

In order to establish a kiln drying schedule for Iranian Beech (Fagus orientalis) lumbers of 5.5 cm thickness, commercially cut from Shast Kola region , 5 km distance from Gorgan. They were then dried under the program based on diffusion theory (from Malmquist's relations) were adopted to dry the lumbers to the final moisture content of 12±2 %. This program for three separate kiln charges and initial moisture content 66.6, 58 and 45 percent was developed. Initial drying bulb temperature (first step) 46 °C and wet-bulb temperature 45 °C was calculated and in three schedules were same. The severity of surface, end checks and warp (bowing, crooking, twisting) in the lumbers were measured before and after the drying process and quality control methods were used to analyze the wood defects. Results indicated that drying of beech lumber using this new schedule was satisfactory. Also intensity changes of defect in all three repeats were about acceptable quality and quantity. Superior characteristics of this program was no surface checks in samples because the moisture content was reduced slowly.

The objective of this study was to determine the influence of Furfurylation treatment on adhesion strength of clear coatings and surface roughness of Beech (Fagus orientalis) wood. Furfurylation of specimens were performed by impregnation and heat catalyze up to 20% and 65% weight percent gain. Half of the specimens coated with acid catalyst paint and half of them coated with polyurethane based paint. Surface roughness and adhesion strength (Pull-off) and cross-hatch cutter test were analysed and compared to untreated specimens. Results revealed that 20% furfurylated specimens did not show significant difference in roughness and adhesion strength, compared to untreated control. But 65% furfurylated specimens caused decline in adhesion strength and raise in surface roughness. Polyurethane based paint had better efficiency and adhesion strength than acid catalyst paint. The highest adhesion strength observed in 20% furfurylated specimens coated with polyurethane and the least obtained in 65% furfurylated wood coated with acid catalyst paint.

In this study, the effect of beech acetylation on the adhesion of transparent paints nitrocellulose lacquer, asid catalyzed lacquer and Half Ppolyester was evaluated. For this purpose, some boards from internal part of beech (Fagus Orientalis) with a relative humidity of 12%, and 12 × 110 × 110 mm was ptepared and were treated by the two levels of acetic anhydride; with the acetylation intensity of 12/5% and 15/5%. Then the two processes were coated separately by transparent paint of nitrocellulose lacquer, asid catalyzed lacquer and Half Ppolyester. The FT-IR test was used to ensure the acetylation process. The results of bond resistance test showed that using of the radial direction compared with tangential direction, the bond strength was higher. Among the samples, the sample treated with acetylation of % 15/5 intensity in comparison with control samples and The lowest percentage of loss of adhesion was observed in control samples.
Survey results showed that the coating by use of nitrocellulose lacquer, Half Ppolyester compared with coating by use of nitrocellulose lacquer, asid catalyzed lacquer, has a higher adhesion strength.

This study was conducted to evaluate stress carrying capacity of miter corner joints fabricated with loose tenon with loose tenon under diagonal tension and compression loading. In this study, tests were carried out to determine the effects of dimension of loose tenon A (3.5 × 1 × 0.8 cm) and B (3 × 2 × 0.8 cm), type of adhesives (Polyvinyl acetate (PVA) and polyurethane (PU)) and most commonly used wood species in furniture industry including beech (Fagus orientalis L.) and fir (Abies alba). The results indicate the stress carrying capacity joints under compression is higher compared with that in tension. Stress carrying capacity joints constructed with dimension of loose tenon A was higher than that of those with B. Furthermore, the results have shown that wood species and type of adhesive had significant effect on the stress carrying capacity and performance of joints constructed of Beech wood and PU adhesive were stronger than joints made of Fir wood and PVA adhesive.

Synthesis of colloidal silver nano-particles، as well as the effect of combined colloidal nano-silver and hydrothermal modification، on weight and chemical changes of wood particles through spectroscopic FTIR were investigated. Treatment levels were divided in 4 groups namely، control، nano- impregnated، hydrothermal and nano-hydrothermal. Hydrothermal and nano-hydrothermal treatments were separated in two temperatures (150 and 170 °C) and two times (30 and 45 min) with total of 10 treatment levels. Colloidal Nano silver with 100 ppm concentration was prepared. The scanning electron microscope images proved the presence، size and appropriate distribution of colloidal nanoparticles silver in wood particles clearly. With regard to the results، increasing time and temperature hydrothermal treatment had significant effect on weight changes. Also، colloidal nano silver intensified weight loss، that maximum weight loss was measured at 170°C. The FTIR spectra indicated that increase in the temperature and time of hydrothermal treatment، declined absorbance intensities in wave numbers of 3422. 25، 2922. 38، 1740. 55، 1330. 50، 1243. 39 and 1053. 05cm-1 due to breakdown of acetyl groups in hemicelluloses and decrease in hydrophilic sites. These reduction in nano hydrothermal treatment were more obvious than those for hydrothermal.

In this study effect of different NDT methods on dynamic properties in beech wood (flexural vibration and longitudinal vibration method) were evaluated. 29 clear samples with nominal dimension of 2×4×36 cm selected and bending vibration in free-free beams and longitudinal vibration tests was performed on them. Results shows strong correlation between dynamic Young''s modulus and acoustic coefficient measured with both Longitudinal vibration and flexural vibration method. Measuring damping factor values was significantly higher in flexural vibration compared to longitudinal vibration method، While the acoustic converting efficiency values from flexural vibration was smaller than values of this factor in longitudinal vibration method. There was good correlation between dynamic shear modulus of elasticity from flexural vibrations and dynamic modulus of elasticity in both methods، that it provides possibility of estimate the shear modulus of elasticity values according to dynamic Young''s modulus of elasticity values from longitudinal vibration test. The results also indicated was a good correlation between the phase velocity in first to third modes from the bending vibration. In addition there was good correlation between sound velocity from longitudinal vibration and the phase velocity in first to third modes from the bending vibration.

The goal of this study was to investigate effects of wood species (Beech and Fir)، number of connectors (1 and 2)، size of biscuit (10 and 20) and type of adhesives (Polyvinyl acetate (PVAc)، polyurethane (PU) and urea-formaldehyde (UF)) on bending moment resistance of joints fabricated with biscuit. Results have shown that member of joint، number of connector، size of biscuit and type of adhesive had significant effect on the bending moment resistance. Bending moment resistance of joints made of Beech wood were stronger than joints made of Fir ones. Bending moment resistance has increased، with the increase of size and number of biscuit. Performance of joints with PU adhesive had better than PVA and UF. Highest bending moment resistance were obtained from joints glued with PU adhesive، size of biscuit 20 and 2 connectors. The results also indicated that joints made with biscuit and glued with PU had higher resistance than wooden dowel joints.

This paper presents a new approach to forest wood production and stand productivity through dendroecology and analysis of the annual tree rings of forest broadleaves species. Based on this approach, samples were collected from different heights of the trees and the circumferential growth and wood production under the growth conditions were determined and the impact of probable competition was investigated. The application of tree dendrochronological method is also considered. The results of this study as part of a comprehensive work showed that in the Caspian forest region, this method can be used for such evaluation for more than last five years. A minimum three tree species namely oriental beech (Fagus orientalis Lipsky), oak (Quercus castaneaefolia C. A. Mey.) and hornbeam (Carpinus betulus L.) in three different elevations along the transect line (profile line) from low (400 m), medium (900 m) and high elevation (1250 m) in Astara, Gilan region were selected. Various behaviors of tree species and their responses to climate changes have been recorded in different elevations.

Environmental and climatic conditions influence growth of the trees as well as beech (Fagus orientalis Lipsky), a species which is widely spread in the Hyrcanian forests in northern region of Iran. However, in the northern border of the forests, Oak (Quercus macranthera) dominates. Despite the variation in the growth and environmental preferences of beech and oak trees, but experiencing similar climatic and environmental impacts. Therefore, the response of the species could be evaluated simulteneously in various watershed districts. Height and standing volume of Fagus orientalis Lipsky and Quercus castaneifolia as wood producing criteria in response to changes in precipitation, temperature, evaporation, longitude, latitude, elevation and ratio of forest cover to total watershed areas across Hyrcanian forest from Astara to Golidaghi-Golestan was investigated. Results showed, mean forest cover elevation increase significantly with increase in longitude but decreased as latitude increases. The ratio of forest covers to total watershed district areas decreased with increasing longitude and latitude. K-means Cluster Analysis for all variables has been done in 2, 3, 4, and 5 cluster groups using SPSS statistical software to produce cluster dendrograms. In all cluster groups, forests category groups were; height and volume of beech, height and volume of oak, precipitation, the ratio of forest cover area to total areas of watershed districts and temperature, The outcome of this research showed that, beech and oak wood production and growth are primarily affected by the precipitation, the ratio of forest cover to total watershed areas and the temperature, and in the secondary level by longitude, latitude and evaporation. Pearson Correlation at the significance levels of 0.01 and 0.05 are presented.