نشریه تحقیقات منابع طبیعی تجدید شونده
سال سوم شماره 3 (پیاپی 9، پاییز 1391)

This study was carried out as completely randomized block in order to study influence of fourpoplar clone plantation on availability of some soil nutrients in Safrabasteh (Astaneh, Guilan Province). Four poplar clones as: 1.Populus euruamerican 214 2.Populus euruamerican 45/51 3.Populus deltoeides77/51 4.Populus deltoeides69/55 were selected in Safrabasteh Poplar Research Station. pH, O.M, N, P, K, Ca and Mg in rhizosphere soil were determined. Results show that difference between clones are significant on soil nutrients except N and Ca. Means comparison show that the Populus euruamerican 45/51 had greater effects on the soil parameters. Comparison the growth characteristics the minimum diameter and height of 15 cm and 12.9 m respectively, with p.e45.51 is dedicated to clone which may indicate less use of plant nutrients to the soil is mostly or returned.

In this research, the effect of nanoclay particles on physical and morphological properties of composites made of almond shell powder/polypropylene was studied. Each of experimental variables was applied in three different concentrations (30%, 35%, and 40% for Almond shell and 0%, 2.5% and 5% for nanoclay). Besides, 2% of maleic anhydride grafted polypropylene was added to all compositions. Afterwards, the nano-composite was manufactured by an injection molding machine. The physical properties including water absorption and thickness swelling of 2-h, 24-h, and 2-h water boiling were measured. Hardness test and scanning electron microscope (SEM) was also performed to investigate fracture surfaces. With regard to the results of physical tests, increase in almond shell increases water absorption and thickness swelling, while the water absorption decrease by increasing nanoclay amount. In all experimental treatments, hardness and density of composites was upper than pure plastic.

The effect of altitude of sea level on physical, biological and morphological properties of hornbeam (Carpinus betulus) is studied in this paper. Some 9 normal hornbeam trees were sampled for this purpose from three different altitudes of sea level (i.e. 300, 750 and 1350 m) from Mashelak Forestry Project (Noshahr, Mazandaran, Iran). Physical and biological properties of their woods were measured using ISO-3131 standard and Franklin method, respectively. The results showed that the altitude of sea level has no significant effect on the physical properties of hornbeam wood (p<0.05). On the other hand, the biological properties of the hornbeam wood are significantly affected by the altitude of sea level. Thereby, increasing the altitude of sea level as well as reduction of length and diameter of the fibers, lumen width, slenderness ratio and flexibility ratio of the hornbeam wood will add to volumetric shrinkage, dried wood density, cell wall thickness and Runkel’s ratio.

In this research, effects of concentration and time of silane treatment of rice straw flour on the physical properties and impact strengths of rice straw flour/polypropylene composites were investigated. In order to of the two concentration of 5 and 10% silane that each concentration had two immersion time 45 and 90 min using for rice straw flour treatments. The simples with cross section, 70
10 mm for physical properties were made using a laboratory twin-screw extruder. For blending the internal raw materials, mixer Haake machines and for making standard testing samples the injection molding were used. The result shown that with increases concentration and time silane treatments rice straw flour water absorption and thickness swelling, sample treatments compare sample without treatments decreases, also impact strength composites with increases concentration and time silane rice straw flour were increases.

This study was conducted to analyze optical properties of nano-titanium dioxide by radiation UV. In this study, is used to poplar samples for measure analyze optical that are sensitive to UV radiation and will be color change easily. The samples impregnated by nano titanium dioxide with three concentrations of 5/0, 75/0, and 1%. Then in artificial weathering system in time intervals of 100, 200 and 400 h placed in a condition which was applied only the UV radiation. Color changes measured using spectrophotometer. Results showed that in treated samples with nano titanium dioxide created little color change rather than untreated samples. So that the effect of nano titanium dioxide protective against UV damage after this period was clearly observeable to untreated samples. Browning in samples that were impregnated with nano titanium dioxide, significantly reduced while the color change occurred in all control samples. Of this observations, concluded that nano titanium dioxide can be used in formulations for wood protection against UV damage.

This research considered the effect of thermal treatment of wood flour in different times and temperatures as an agent for treat properties of Populus wood flour/recycled polypropylene composites. Water absorption and thickness swelling tests as physical properties, tensile and bending strength as mechanical properties evaluated. The experimental results indicated that samples treated in 60 minutes and 200ºC had the lowest amounts in water absorption and thickness swelling tests but about samples treated in 20 minutes, 160 and 180ºC observed that the samples were treated in 160ºC had low amount of water absorption (63%) than the samples were treated in 180ºC (76%). Measuring of mechanical properties showed that the variable properties of composites were increased with the rising heat time, while the samples were treated at 60 minutes had 97% followed by the samples treated at 20 minutes had 14% amount more than control samples.