Treesearch

Nanotechnology is the study and engineering of matter at the dimensions of 1 to 100 nanometers, where the physical, chemical, or biological properties are fundamentally different from those of the bulk material. By expanding our understanding and control of matter at such levels, new avenues in product development can be opened. Nanoscale-based science has applications across nearly all economic sectors and allows the development of new technologies with broad commercial potential, such as nanostructured materials, nanoscale-based manufacturing processes, and nanoelectronics. However, to...

The dry rot fungus, Serpula lacrymans, is one of the most destructive copper-tolerant fungi causing timber decay in buildings in temperate regions. Calcium and oxalic acid have been shown to play important roles in the mechanism of wood decay. The effect of calcium on growth and decay was evaluated for 12 strains of S. lacrymans and compared to five brown-rot fungi. This was done by treating copper citrate (CC)-treated Southern yellow pine (SYP) wood with a CaCl2 solution and estimating the decay rate and amount of soluble oxalic acid in an ASTM soil block test. Decay by S. lacrymans was...

Understanding heat and moisture transfer in a wood specimen as used in the K-tester has led to an unconventional numerical solution arid intriguing protocol to deriving the transfer properties. Laplace transform solutions of Luikov’s differential equations are derived for one-dimensional heat and moisture transfer in porous hygroscopic orthotropic materials and for a gradual finite heat pulse applied lo both surfaces of a flat slab. The K- tester 637 (Lasercomp) supplies a quasi-heat-pulse to both sides of a 2-ft-square specimen and records precise signals as function of time from surface...

Down-regulation of the gene encoding 4-coumarate 3-hydroxylase (C3H) in alfalfa massively but predictably increased the proportion of p-hydroxyphenyl (P) units relative to thenormally dominant guaiacyl (G) and syringyl (S) units Stem levels of up to ~65% P (from wild-type levels of ~1%) resulting from down-regulation of C3H were measured by traditional degradative analyses as well as two-dimensional 13C-1H correlative NMR methods. Such levels put these transgenics well beyond the P:G:S compositional bounds of normal plants; p-hydroxyphenyl levels are reported to reach a maximum of 30% in...

Challenges for wood-thermoplastic composites to be utilized in structural applications are to lower product weight and to improve the long-term load performance. Silane crosslinking of the composites is one way to reduce the creep during long-term loading and to improve the mechanical properties. In this study, silane crosslinked wood-polyethylene composites were produced by reactive extrusion and subsequently manufactured into rectangular profiles. The silane crosslinked composites were stored in a sauna at 90 °C to increase the degree of crosslinking. The toughness of the silane crosslink...

Certain wood decay fungi exhibit tolerance to one or more wood preservatives. Copper tolerance of brown-rot fungi has been studied in our laboratory for the past six years. We have observed some degree of tolerance to N’N-naphthaloylhydroxamine (NHA), a recently patented termite bait, by the brown-rot fungus Tyromyces palustris TYP-6137. In an effort to try and confirm this tolerance in other isolates of T. palustris and to dissect the mechanism of tolerance, an additional ten isolates of T. palustris were tested in soil-block bottles for 12 weeks against southern yellow pine wood blocks...

Melamine–formaldehyde adhesives form wood bonds with exterior durability, and the melamine is more easily studied because of its significant nitrogen content (compared with the lack of nitrogen in wood components). In addition, some melamine–formaldehyde chemicals reduce wood swelling [6], enter into wood cell walls [7], and strengthen them [8]. This information led to investigation on the use of melamine-based primers for improving the durability of epoxy-bonded wood. Epoxies bond well to wood, providing good shear strength and high wood failures under dry conditions. However, under wet...

The wood anatomical characteristics of Dalbergia nigra and Dalbergia spruceana are too similar to permit reliable species separation, which is sometimes important because D. nigra is a Convention on International Trade in Endangered Species-protected species whereas D. spruceana is not. However, the density, water fluorescence, and ethanol fluorescence of heartwood specimens are different between the species and these chracteristics permit the separation of the species. Dalbergia spruceana is denser (≥1.0 g/cm3) than D. nigra (

This report provides general and statistical information on forests products markets in terms of production, trade, consumption, and prices. The current state of the U.S. economy is described. Market developments are described for sawn softwood, sawn hardwood, softwood log trade, wood- based panels, paper and paperboard, fuelwood, and forest product prices. Policy initiatives that can affect domestic markets and international trade in wood products are also discussed in some detail. Projections for the year 2006 are also presented.

For most markets for wood, it is used without any treatments or modifications. When wood is used in adverse environments, it may be treated with chemicals to help prevent decay, improve water resistance, reduce the effects of ultraviolet radiation or increase fire retardancy. Many of these treatments involve the use of toxic or corrosive chemicals that can harm the environment. Chemical modification of wood provides an alternative by providing protection against water, decay, UV and thermal degradations by bonding chemicals to the cell wall polymers that do not leach out. Dimensional...