Treesearch

We describe the structure, organization, and transcriptional impact of repetitive elements within the lignin-degrading basidiomycete, Phanerochaete chrysosporium. Searches of the P. chrysosporium genome revealed five copies of pce1, a 1,750-nt non-autonomous, class II element. Alleles encoding a putative glucosyltransferase and a cytochrome P450 harbor pce insertions and produce incomplete transcripts. Class I elements included pcret1, an intact 8.14-kb gypsy-like retrotransposon inserted within a member of the multicopper oxidase gene family. Additionally, we describe a complex insertion...

The influence of four fire-retardant systems on the planar (rolling) shear properties of structural hardwood plywood is evaluated using two possible ASTM D2718 test methodologies: the plate-shear method and the five-point flexural shear method. Knowing the planar shear properties and the potential of the various fire-retardant systems to affect properties is critical in engineering design. The various fire-retardant systems were found to reduce plate shear properties for plywood more than flexural shear properties depending on the fire-retardant chemical and its chemical loading level. We...

Renewable and sustainable composite materials can be produced using forest biomass if we maintain healthy forests. Small diameter trees and other forest biomass can be processed in the forest into small solid wood pieces, sliced veneers, strands, flakes, chips, particles and fiber that can be used to make construction composite products such as glued-laminated lumber, plywood, structural composite lumber, flakeboard, particleboard, fiberboard, and molded materials. It can also be combined with other resources to make new materials taking advantage of the unique properties of each resource....

This paper evaluates the effect that uncertainties in measurements of time, weight, and surface area have on the determination of the corrosion rate of metal fasteners in contact with wood. Three different types of nails were driven into alkaline copper quaternary (ACQ)-treated wood and exposed to 26.7°C (80°C) at 100 % relative humidity environment for up to 1 year. It was observed that uncertainties in measurement of corrosion rate of less than 5 % could be obtained in 6 months of testing. This paper gives a description of the methods used as well as recommendations for future corrosion...

The purpose of this work was to test some of the assumptions underlying methods currently employed to investigate nanoindentation properties of wood. We examined whether hardness and modulus depend on load. We employed a surface preparation technique that minimizes alterations of cell wall properties. Areas were determined using both (a) Oliver-Pharr method and (b) a calibrated atomic force microscope (AFM).

This study evaluates the effect of moisture content on the properties of 127- to 152.4-mm (5- to 6-in.-) diameter lodgepole pine (Pinus contorta Engelm.) logs that were tested either in bending or in compression parallel to the grain. Lodgepole pine logs were obtained from a dense stand near Seeley Lake, Montana, and sorted into four piles of 30 logs each. Two groups were tested in bending, one green and one dry, and two in compression parallel to the grain. The results of the study provide conservative procedures for estimating compression strength for green logs based on the assigned...

The recent increase of wood-plastic composite materials in various application areas has underlined the need for an efficient and robust methodology to characterize their nonlinear anisotropic constitutive behavior. In addition, the multiplicity of various loading conditions in structures utilizing these materials further increases the need for a characterization methodology that accounts for this complexity. In responding to these needs, this paper presents a data-driven methodology that utilizes multi-degree of freedom mechatronic loading systems to systematically collect behavioral data...

After millions of years of evolution, wood was designed to perform in a wet environment, and nature is programmed to recycle it, in a timely way, back to the basic building blocks of carbon dioxide and water through biological, thermal, aqueous, photochemical, chemical, and mechanical degradation. The properties of wood are, for the most part, a result of the chemistry of its cell wall components. The polysaccharides (cellulose and hemicelluloses) are mainly responsible for (i) moisture uptake and release in changing environments that result in changes in wood volume (dimensional instabilit...

Jute is the common name given to the fiber extracted from the stems of plants belonging to the genus Corchorus, family Tiliaceae. whereas kenaf is the name given to a similar fiber obtained from the stems of plants belonging to the genus Hibiscus, family Malvaceae, especially the species H. cannabinus L. Only two species of Corchorus, namely C. capsular L. and C. olitorius L., are grown commercially, although around 40 wild species are known, whereas other species of Hibiscus, particularly H. sabdariffa L. are sometimes also marketed as kenaf. These plants are examples of a number of...

Medium density fiberboard (MDF) panels were made with aspen fiber and 0-95% chicken feather fiber (CFF) in 2.5%, 5%, or 25% increments, using 5% phenol formaldehyde resin as the adhesive. Panels were tested for mechanical and physical properties as well as decay. The addition of CFF decreased strength and stiffness of MDF-CFF composites compared with that of all-wood control panels. However, MDF-CFF panels showed a marked improvement in resistance to water-soak absorption, which provided limited protection against decay fungi. This benefit was probably related to the hydrophobic keratin in...