this research was conducted in the west forest of guilan, northern iran. data from various harvesting methods for 20 years were collected. results showed that, productivity rate of round wood, pulp wood and fuel wood has had an upward trend, while rate of traditional products (lumber, sawn wood, charcoal, etc.) has had a downward trend. production cost has been investigated in this research. th...

Epidemiological evidence indicates that common environmental allergens found in building reservoirs are strongly associated with the development of bronchial hyper-reactivity (BHR) or asthma, affecting up to half the population in North America and Europe. Although they are rarely life threatening, these diseases cause much distress and lost time from school and work. These diseases are believe...

the mean fiber length of three beech trees (fagus orientalis l.) at the lower and higher points (1% and 75% tree height) of the stem at an intermediate altitude (500-1000m) in the caspian forests in sari region were 1.36 and 1.22mm respectively, close to the values in three trees at high altitude (1000-1500m), that were found to be 1.39 and 1.36 mm. the mean fiber lengths of the whole stem, usi...

wood vinegar is the aqueous phase of the liquid produced during the slow pyrolysis of wood.it has the potential to be used as a pesticide against various weeds, insects and molluscs. due to divergentfeedstocks, pyrolysis processes and storing conditions, the chemical composition of wood vinegar variesbetween producers and time. the aim of our current study was to use the copse snail arianta arb...

Wood is a porous three dimensional, hydroscopic, viscoelastic, anisotropic bio-polymer composite composed of an interconnecting matrix of cellulose, hemicelluloses and lignin with minor amounts of inorganic elements and organic extractives. Some, but not all, of the cell wall polymer hydroxyl groups are accessible to moisture and these accessible hydroxyls form hydrogen bonds with water. As the...

With the development of civil engineering, construction level is also constantly improving. Engineering crack a common problem, when concrete structure appeared cracks, will lead to bearing capacity structure, durability and waterproof other reduced, seriously affect normal use so it very necessary take remedial measures. In this project, chemical adhesive epoxy resin were used for repairing in...

This study is a first step toward identifying some factors influencing spatial presence, enjoyment, and cognitive workload in virtual reality (VR) game play. The was conducted the Northeastern U.S. (n = 40) Southwest Nigeria using factorial experimental design with three environmental (i.e., lighting, flooring, in-game sound) at two levels per factor. Participants were randomly assigned to one ...