Treesearch

Treating wood with the water-borne sodium salt of N'-N-naphthaloylhydroxylamine (Na-NHA) protects wood against decay and termite damage. Initial testing indicated little or no inhibition of sapstain fungi, molds, or soft-rot fungi by Na-NHA, suggesting that the mechanism by which this compound protected wood was complex and not that of a broad-spectrum biocide. Previously, we (Green et al, 1997) suggested that the protective mechanism was due to Na-NHA complexing with calcium ions to disrupt fungal metabolism, and/or binding of Na-NHA to the calcium in pit membranes, which acts as a...

As part of efforts to address fire problems in the wildland-urban interface, the cone calorimeter is being used to measure the relative flammability of different plant species. In the first two studies, we tested plants used to landscape homes in California and an assortment of plants found in Colorado. Using the effective heat of combustion and the peak heat release rate, we found significant differences between some plants. Current efforts include a study of the relative flammability of native and invasive plants of the northeastern United States. We need to continue our evaluation of...

Hygrothermal models can predict temperature and moisture conditions in wall components subjected to real weather data, but specific data and a fundamental understanding of how temperature and wood moisture content dictate the progression of decay under these conditions is required for modellers to predict consequences of decay on building performance. It is well understood that wood will decay above 30% moisture content and will not decay below 20% moisture content. Moisture contents between 20% and 30% represent a grey area. This paper describes cooperative work underway at our two...

Bioremediation processes for recovery and reuse of CCA-treated wood invariably increase the cost of any secondary products manufactured from the remediated fiber. Microbial remediation using either bacteria or fungi has been shown to remove heavy metals from CCA-treated southern yellow pine (SYP). In a two-step remediation process utilizing oxalic acid extraction and the metal-tolerant bacterium Bacillus licheniformis, 70-100% of the copper, chromium and arsenic can be removed from CCA-treated SYP, but the liquid culture medium used to support the bacterial growth renders this process...

A peroxidase-encoding gene, mnp2, and its corresponding cDNA were characterized from the white-rot basidiomycete Trametes versicolor PRL 572. We used quantitative reverse transcriptase-mediated PCR to identify mnp2 transcripts in nutrient-limited stationary cultures. Although mnp2 lacks upstream metal response elements (MREs), addition of MnSO4 to cultures increased mnp2 transcript levels 250-fold. In contrast, transcript levels of an MRE-containing gene of T. versicolor, mnp1, increased only eightfold under the same conditions. Thus, the manganese peroxidase genes in T. versicolor are...

2-Hydroxymethylphenol (2-HMP) and 4-hydroxymethylphenol (4-HMP) were used as model compounds to study the reactions that occur during cure of phenol-formaldehyde (PF) resin to which cure accelerators (ethyl formate, propylene carbonate, g-butyrolactone, and triacetin) have been added. The addition of cure accelerators significantly increased the rate of condensation reactions. The cure accelerators were consumed during the reaction, indicating that they do not act as true catalysts. Major dimeric and trimeric reaction products were isolated and their structures determined. The results are...

The combustion properties of various biomass and wood materials from various references and from our laboratory were reanalysed. The net heat of combustion for cellulosic materials was found to be 13.23 kJ/g times the ratio of stoichiometric oxygen mass to fuel mass, r[subscript]o, regardless of the material composition. Bomb calorimeter data for original, charred and volatilized material components provide gross heating values, while elemental analysis of the materials for carbon, hydrogen, oxygen and ash provide direct evaluation for r[subscript]o. We corrected these data as provided in...

Structural lumber products are traditionally manufactured from softwoods. However, with shrinking supplies of softwood lumber and abundant supplies of hardwood lumber, there is increasing interest in the use of hardwoods for structural applications. One factor that will be important in both the technical and economic feasibility of using hardwoods for structural lumber is drying. This paper presents some results on developing accelerated kiln schedules for drying hard maple 2 by 6s for structural uses.

The Forest Products Laboratory (FPL) has a long history of research and technology transfer in lumber drying. Many of the dry kiln schedules used in industry today were developed by the staff of the Laboratory, and for many years the Laboratory conducted a kiln drying short course for training dry kiln operators. The purpose of this report is to describe the Laboratory’s current research activities in lumber drying as well as the more recent issue of heat sterilization.

Mechanical properties of bending stiffness and yield stress were used to evaluate the effects of ultraviolet exposure on natural fiber-thermoplastic composites. Four different specimen formulations were evaluated. Injection molded high density polyethylene (HDPE) served as the polymer base for all formulations. Two lignocellulosic fillers, wood flour and kenaf fiber, were added at 50 percent by weight. Additives consisted of an antioxidant, coupling agent, and ultraviolet (UV) stabilizer. Specimens were exposed in a laboratory weatherometer to high levels of UV radiation and moisture...