Treesearch

Bioremediation is a novel approach to recycling waste wood treated with chromated copper arsenate (CCA). Remediating CCA-treated waste wood diverts this fiber source from our landfills and provides tangible secondary products from the cleaned fiber. On a laboratory scale, this method, which utilizes oxalic acid extraction and bioleaching with a metal- tolerant bacterium, removed up to 78% Cu, 100% Cr, and 97% As from 1 kg chipped CCA-treated southern pine. The two-step sequence of oxalic acid extraction and bioleaching removed more metals than did either acid extraction or bioleaching...

Before initiating a survey or a monitoring program of any group of organisms in an area, an investigator should carry out some preliminary background research. Essential materials for the research include maps of the area and descriptions of its climate, geology, and vegetation. Learning to recognize the woody plant species and major plant associations likely to be encountered is particularly important. Knowledge of the anticipated species diversity and distributions of the macrofungi is also very helpful. Such background information increases an investigator’s understanding of the habitat...

White rot fungi efficiently degrade lignin, a complex aromatic polymer in wood that is among the most abundant natural materials on earth. These fungi use extracellular oxidative enzymes that are also able to transform related aromatic compounds found in explosive contaminants, pesticides and toxic waste. We have sequenced the 30-million base-pair genome of Phanerochaete chrysosporium strain RP78 using a whole genome shotgun approach. The P. chrysosporium genome reveals an impressive array of genes encoding secreted oxidases, peroxidases and hydrolytic enzymes that cooperate in wood decay....

Large amounts of woody residues and solid wood waste are generated annually in the United States from the extraction of timber from forests, from forestry cultural operations, in the conversion of forest land to nonforest uses, in the initial processing of roundwood timber into usable products, in the construction and demolition of buildings and structures, and in the manufacture, use, and disposal of solid wood products in the municipal solid waste stream (MSW). Much of this material is indeed waste, but large, increasing shares are now becoming valuable resources. Here we examine the two...

The USDA Forest Service, Forest Products Laboratory (Madison, Wisconsin)and the Wood-Based Composites Center of Virginia Tech (Blacksburg, Virginia) co-sponsored a conference, held November 5–6, 2003, in Madison, Wisconsin, on the fundamentals of composite processing. The goals were to assess what we know, define what we need to know, and then establish the state of the art in hot-pressing of wood-based, particulate composites. Academic and industrial professionals from around North America and Europe were invited to participate because of their expertise and interest in this area of...

In this study, effect of MAPE (maleic anhydride polyethylene) as the compatibilizer on the mechanical properties of wood-flour polyethylene composites has been investigated by using Dynamic Mechanical Analysis (DMA). Composites were made at 25% and 50% by weight fiber contents and 1% and 2% compatibilizer respectively. Controls were also made at the same fiber contents without the compatibilizer. Static mechanical tests including tensile and bending tests were performed. Temperature scans in the range of - 110 to +100°C was also conducted. Results indicated improvements in the mechanical...

It is commonly accepted that the fire retardant mechanism of boric acid is a physical mechanism achieved by the formation of a coating or protective layer on the wood surface at high temperature. Although a char-forming catalytic mechanism has been proposed by some researchers, little direct experimental support has been provided for such a chemical mechanism. In this paper, new experimental results using thermal analysis, cone calorimetry (CONE), and gas chromatography–Fourier transform infrared spectroscopy (GC–FTIR) analysis are presented and the fire retardant mechanism of boric acid...

This study aims to explore the processing benefits and property improvements of combining nanocomposites with microcellular injection molding. The microcellular nanocomposite processing was performed on an injection-molding machine equipped with a commercially available supercritical fluid (SCF) system. The molded samples produced based on the Design of Experiments (DOE) matrices were subjected to tensile testing, impact testing, Dynamic Mechanical Analysis (DMA), and Scanning Electron Microscope (SEM) analyses. Molding conditions and nano-clays have been found to have profound effects on...

Several hardwood timber bridges were constructed in Pennsylvania during the early 1990s. This report summarizes the long-term field performance of seven stress-laminated deck bridges over a 4-year period beginning August 1997 and ending July 2001. Data collected include lumber moisture content, static load test deflection measurements, and bridge condition assessments. In addition, stressing bar force, temperature, and relative humidity conditions were monitored several times per day by a remote data acquisition system installed at each bridge site. Superstructure lamination moisture...

Conflicting reports on levels of arsenic in soil beneath decks treated with chromated copper arsenate (CCA) have raised concerns about arsenic exposure from this type of treated wood. This paper reports on an evaluation of the rate of release of copper, chromium, and arsenic from commercially treated lumber as a function of treatment additive (with or without water repellent) and rate of rainfall. Treated lumber was purchased from several retailers at three times over the course of a year, and exposed under laboratory conditions to simulated rainfall at rates of 2.5, 8.0, or 25.4mm/hr., up...