Treesearch

This chapter describes a new cyclic fatigue test apparatus (CFTA) developed at the USDA Forest Service, Forest Products Laboratory. The new CFTA is computer controlled and powered by electric linear actuators. Computer control allows the CFTA to subject specimens to specific strain/time profiles or replicate input strain data in real time from thermal and/or moisture driven cyclic movement of materials such as metals, glass, ceramics, and wood. The CFTA was designed for outdoor sealant testing but is readily adaptable for testing other materials.

The desire to make more environmentally friendly and lower-cost bonded wood products has led to an interest in replacing some phenol and formaldehyde in wood adhe- sives with soybean flour. It is important to develop tests that relate resin production variables to resin properties before and after wood bonding. The protein needs to be denatured, with minimal hydrolysis, to maximize its incorporation into the final polymerized structure. In this study, the best conditions for denaturing were found to be maintaining the temperature below 100°C and reacting the soy flour with sodium hydroxide...

A novel green adhesive with high soy content has recently been developed (13) with a process that denatures soy flour, modifies resulting protein with formaldehyde, and uses suitable phenolic crosslinking agents for copolymerization. Compared with mechanical and physical performances of oriented strandboard, the new adhesive showed promise for improving panel performances and lowering costs. We studied the effects of four variables (face-resin content, face-furnish moisture content [MC], density of the panels, and press time) on panel performances and identified possible interactions with...

Fungal tolerance to wood preservatives has been critically important for many years. The tolerance of type cultures to common wood preservatives is, in fact, noted in the AWPA Standards [1]. Gloeophyllum trabeum Mad-617, for example, is particularly tolerant to phenolic and arsenic compounds. One important group of decay fungi that has been studied extensively are those that are copper tolerant such as Postia placenta MAD-698, which is particularly tolerant to copper and zinc compounds [1]. Recently, Tyromyces palustris and Serpula lacrymans, the European dry rot fungus, have also been...

Structural transformation of lignin in pulps bleached with polyoxometalates (POMs) should be explored in order to gain insight into the lignin reactions leading to its solubilization during POM treatment of kraft pulp. Our studies include characterization of residual lignin isolated from softwood commercial and birch laboratory kraft pulps delignified with POMs. Oxidative treatment of unbleached kraft pulps, commercial mixed softwood and laboratory birch, was performed using complex POM solutions containing the active [SiVW11O40]5- anion. Kappa number and contents of Klason lignin and...

The North American Pulp and Paper industry continues to experience challenges and changes much like most other business sectors of the hardwood industry. Marketing policies and the raw material supply chain of pulpwood and chips are being affected. The issues surrounding supply for pulpwood and chips have a broad reach in affecting timber and log purchases, logging contractors and sawmill operations throughout the hardwood industry, particularly in the Southern region. Availability and pricing of timber and logs can be impacted by positive or negative factors surrounding the pulpwood and...

If America had Canada’s stumpage system, then there wouldn’t be much of a dispute. But the reality is there are two distinct models of timber valuation, and the core of America’s complaint vis-à-vis Canada is that, as a result, there is an asymmetry in the market where the two sides compete: on the one hand all producers have equal access under the same rules and standards to the U.S. lumber market, but at the timber supply level a different and exclusionary Canadian lumber pricing model provides wood at rates that disadvantage U.S. competitors. Canadians acknowledge that Canada has a...

Juniper (Juniperus monosperma), a small-diameter underutilized material, has been studied as a lignocellulosic bio-sorbent for removing heavy metals from water. In this study, juniper wood was modified by sulfonation to enhance sorption capacity for cadmium in water. The origin of the enhancement was investigated by observing the sorption behaviors and the change in surface functional group concentrations. Cadmium sorption by all juniper wood biosorbents studied was fast and the sorption capacity decreased with decreasing pH, similar to results found for other bio-sorbents. Sulfonated...

The time–temperature superposition principle was applied to the viscoelastic properties of a kenaf- fiber/high-density polyethylene (HDPE) composite, and its validity was tested. With a composite of 50% kenaf fibers, 48% HDPE, and 2% compatibilizer, frequency scans from a dynamic mechanical analyzer were performed in the range of 0.1–10 Hz at five different temperatures. Twelve-minute creep tests were also performed at the same temperatures. Creep data were modeled with a simple two-parameter power-law model. Frequency isotherms were shifted horizontally and vertically along the frequency...

Party on or last hurrah? A year ago the answer was relatively easy: Let the good times roll! Now, post election in a maturing recovery, it’s less clear cut. Nonetheless, recent fears by some that the outstanding economic environment that existed for lumber in 2004 is passé seem premature. Recent trends contrasted with the 1972-74 experience, a period that shares many commonalities with the present, support this view.