Iranian Journal of Wood and Paper Science Research
Year:2006 | Volume:21 | Issue:1 (24)|Papers Count:6

Ultrasonic wave speed was measured in the longitudinal direction of Basswood on the top and bottom surfaces and center of lumbers during kiln drying in 3 Kiln load programs with final dry bulb of 80oC and different relative humidities. On the surfaces, wave speed decreased rapidly with MC declining from green to FSP, but from FSP down to 7% moisture content wave speed did increased slowly. In the center of lumber, with decreasing MC from green to FSP, wave speed increased slowly, but by reducing MC to 7%, wave speed was rapidly increased. 5% MC, on the three surface of lumber, wave speed had no drastic difference. Results indicated that ultrasonic wave speed and MC of wood show a parabolic relationship. Further, results have shown that measuring ultrasonic wave speed is an appropriate method to control kiln drying program for hardwood lumber.

In this study, in order to achieve sufficient accuracy both quality and quantity factors in two forestry plantanation of Picea abies using 100% statistics were used. In order to investigate wood quality, fiber length, density and mechanical properties, 4 thick cross section trees were selected and cut in two area of Piseson at high 1450m. altitude and Syahkal at 650m. altitude. According to the results of measuring of diameter, height and average annual growth of the samples and comparison of different sites condition, it could be concluded that plantation of Picea abies is advantageous. Finally, the results show that in Piseson wood with low mechanical properties were produced. The average annual growth of wood in Piseson is 63mm. where as in syahkal is 60mm.

The property of MDF obtained the mixture of Haloxylon persicum wood (Saxaul) with Carpinus betulus (Hornbeam) at 100:0, 75:25, 50:50, 0:100 ratios is investigated in this study. The results of this study showed that there is significant statistical differences (1%) among combinations of woods for MOR, MOE, IB, thickness swelling after 2 & 24 hours and water absorption after 2 & 24 hours. The bending strength (MOR) of MDF produced of Hornbeam wood fibers was highest and Saxaul wood fibers were lowest. Boards produced from 50% Hornbeam and 50% Saxaul, showed the important of bending strength 57%. The average modulus of elasticity (MOE) of MDF showed significant statistical differences (1%). MDF produced from Hornbeam wood fibers had showed highest MOE and Saxaul wood fibers showed lowest MOB. The result of internal bonding (IB) showed that MDF produced from Saxaul wood fibers possessed lowest IB and Hornbeam wood fibers had highest IB. In other two combinations of Hornbeam and Saxaul wood fibers, there are no significant statistical differences (1%) with MDF produced from only of Hornbeam wood fibers.

The possibility of producing wood-plastic panels using two methods including melt blend and dry blend was studied in this research. Methods were compared with each other in order to select the best. Wood-Plastic panels were made from high density polyethylene (as resin) and particle board waste (as natural fiber) at 60, 70 and 80% by weight fiber loading. Density and dimensions of the panels were lg/cm3 and 35*35*1 cm, respectively. Mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistance, and impact strength were under investigation. Maximum values of flexural modulus of wood plastic panels were found at 70% fiber content in both methods. Flexural strength, screw and nail withdrawal resistance and impact strength of wood plastic composites reduced with the increase in fiber content from this is not a reduction 60% to 80% is increase. Mechanical properties of samples made with dry blend method were generally higher than those of samples made with melt blend method for an corresponding formulations.

The common reed, P.australis, covers vast region in south of Iran. Specially, there is possibility of executing harvest in Hoor-Alazim canebrake as a reed natural provenance. It has good properties for papermaking in comparison of typical nonwood materials. Chips were pulped using typical kraft, soda and NSSC processes. Standard testing of pulp properties was made using TAPPI procedures. Pulps were beaten in a PFI mill to 400m.l.csf freeness level. Handsheets were made from the refined reed pulps for measuring strengths. Screen yield and kappa number of soda pulp were about similar to kraft pulp. NSSC pulp has lower kappa number than the soda at the equivalent screen yield. Energy consumption for beating from kraft, soda and NSSC pulps reduced respectively. Initial freeness of reed pulp was near to hardwood typical, thus good drainage and runnability on reed papermaking is expectable. The physical properties of reed handsheets were higher than newsprint and fluting pulps of Mazandaran Company. Overall, soda and NSSC reed pulps can be used in producing of newsprint and fluting papers based on the properties.

In this study, the damage of termites on Eucalyptus wood (Eucalyptus intertexta R.T. Baker) in both treated and untreated conditions was evaluated by IRGfWP-1290 and recommendation of ASTM Standard D-1758 methodes. The dimention of the samples were 25 x 2.5 x 2.5, 30 x 8 x 8 and 47 x 2 x 2cm that were treatd by celcure and Creosote using full cell process (Bethel) method. Retentions average of Creosote and Celcure were 53.22, 5.62 Kg/m3 respectively. The studies have shown that untreated samples of E. intertexta which have been placed in field test for 9 years, were subjected to damage about 70%, and soft rot could be seen on them. Samples treated by Celcure and Creosote which have been placed for 6 years were sound but in the 7th year the damage of the termites on the samples began to appear which was 20%. Based on this study, it can be concluded that E. intertexta wood can be classified as a moderately durable wood.