Treesearch

Lyophilization is an excellent technique for the long-term preservation of hyphal-forming brown-and white-rot wood-inhabiting basidiomycotina. However, vegetative mycelial isolates are not lyophilizable. In this study, 10 brown-rot and 10 white-rot basidiomycetous non-sporulating, non-chlamydosporulating, and non-bubillerferous basidiomycetes fungi were tested for viability after lyophilization. Optimization of the lyophilization involved (i) using mycelium agar plugs and mycelial fragments, (ii) improving physiological growth conditions, age of cultures, and growth medium components,...

A polyoxometalate-catalyzed electrochemical process has shown good selectivity in delignifying pulp. This breakthrough in redox catalysis shows promise for the development of a new environmentally benign technology for pulp bleaching. The electrochemical process, applied with a mildly alkaline electrolyte solution containing trace amounts of a vanadium-based polyoxometalate, K5[SiVW11O40], decreased the kappa number of a softwood Kraft pulp by about 40% without significant change in the viscosity of the pulp. In a similar electrochemical process, a softwood semi-bleached Kraft pulp was...

In this era of performance-based building codes, there is an increased need for models and data pertaining to the fire safety of building materials. In addition to data for the prescriptive regulatory fire tests, material property data are needed to optimize the advantages of the performance-based building codes that are being introduced worldwide. In this review of our research on the fire performance characteristics and fire safety engineering of wood products, we will present results on the fire performance of hardwood species. Two broad areas of fire safety engineering of materials are...

Because more homes are being built in the forests and other wildlands, the safety of these homes during forest fires has become a major issue. Although not noted for loss of life, fires in the wildland/urban interface (WUI) are responsible for extremely large property losses. Approaches to this problem include improved management of the forests to reduce fuel loadings, improved fire service response, improved community design, and improved home designs. Unlike the normal house fire, the forest fire represents an exterior fire exposure. As such, the components of a home that can immediately...

Southern pine solid wood (SPS) and fiber (SPF) were chemically modified to various weight percent gains (WPG) using either acetic anhydride (AA, 4%-19% WPG), butylene oxide (BO, 4%-23% WPG), or propylene oxide (PO, 6%-30% WPG). After modification, part ofthe specimens were extracted with a toluene:ethanol (2:1) solution for 2 hours or water leached for 2 weeks. The equilibrium moisture content (EMC) at 30%, 65% and 90% relative humidity (RH) and 27 °C was determined on all specimens. Laboratory soil block decay testing using the brown-rot fungus Gloeophyllum trabeum was performed and...

Moisture content has an effect on the biological decay of wood. The literature states that serious decay occurs when the moisture content of wood is above the fiber saturation point (FSP), which is the measurement of the moisture content of wood when the cell walls are saturated and the cell cavities free from water (average 30%). We can chemically modify wood hydroxyls by various treatments (i.e., acetylation, isocyanates, and epoxides) which result in the lowering of the FSP. If we modify the availability of water in the cell wall, we can reduce or eliminate biological degradation. So is...

In a series of papers Verrill, Green, and Herian have developed theory and a computer program to aid in the design and analysis of predictor sort experiments. In this paper we provide the mathematical justification for the power calculations that the predictor sort program implements.

The use of soluble salts of polyoxometalates (d0-early-transition metal oxygen-anion clusters or POMs) as selective oxidation or electron-transfer catalysts, as probes in physical-organic and biological chemistry, and in the study of electron-and energy-transfer phenomena constitutes a substantial and rapidly growing literature. While rarely addressed, however, POM solutions contain equilibrium distributions of free anions and ion-paired structures of variable stoichiometry. Thus, although studies of crystalline POM salts used in heterogeneous catalysis clearly indicate that cation-anionint...

Recently found experimental evidence has provided strong support for an alternative photoyellowing mechanism that suggests that pulp- photoyellowing occurs due to direct photooxidation of hydroquinones (present in mechanical pulps) top-quinones. Because hydroquinones were found to be present in pulps, it may be possible to quantify them. Quantification of mechanical-pulp hydroquinones is important because it would provide information on a pulp's potential for photoyellowing. One of the ways to accomplish this is to use the method that successfully detected hydroquinones, namely the method...

Environmental pressures to replace chromium and arsenic in fixed waterborne preservatives have been increasing. Potential inhibitors of brown-, white- and soft-rot fungi need to be evaluated as alternative preservatives by screening and testing in, in vitro model systems. This paper reports the inhibition of cellulose depolymerization and weight loss of selected decay fungi by 11 chemical compounds. The ability to depolymerize carbohydrate polymers is analogous to strength loss of wood which can occur independently of utilization (weight loss). Cotton cellulose was pretreated with 1%...