Treesearch

For 75 years the Forest Products Laboratory has been concerned for the wise use of wood. One of the major uses of wood is packaging. This report summarizes the research reports completed in packaging and relates the output in terms of forest management and return on the taxpayer’s investment.

Batch hydrolysis kinetics of paper birch (Betula papyrifera) xylan and its associated acetyl groups in dilute sulfuric acid have been measured for acid concentrations of between 0.04 and 0.18 M and temperatures of between 100 and 170°C. Only 5% of the cellulose was hydrolyzed for up to 85% xylan removal. Rate data were correlated well by a parallel reaction model based on the existence of reactive and resistant xylan portions. The resulting rate equation predicts the experimental xylan concentrations in the residue to within 10%. Hydrolysis of xylan-associated acetyl groups was found to...

Log breakdown simulation models have gained rapid acceptance within the sawmill industry in the last 15 years. Although they have many advantages over traditional decision making tools, the existing models do not calculate yield correctly when used to simulate the breakdown of eccentric, sweepy logs in North American sawmills producing softwood dimension lumber. In an attempt to overcome these limitations, the Best Opening Face (BOF) model has been modified to simulate logs with sweep and elliptical cross sections. This paper discusses applications of the modified BOF model. These include...

A discussion of the interaction between wood and water makes clear the distinction between water repellency of wood (a rate of change) and dimensional stability (a level of equilibrium). A review of methods of treating wood follows, leading to comparison of their effectiveness, description of test procedures to evaluate treatments, and discussion of deficiencies of the tests commonly used, first with regard to water repellency, then to dimensional stability, with final consideration of future research. Figures, numerous tables (introducing some new data), and an extensive bibliography...

The fuelwood harvesting computer program (FHP) is written in FORTRAN 60 and designed to select a collection of harvest units and systems from among alternatives to satisfy specified energy requirements at a lowest cost per million Btu's as recovered in a boiler, or thousand pounds of H2O evaporative capacity kiln drying. Computed energy costs are used as a criterion of economic viability. Sensitivities of energy costs and fuel requirements to changes in moisture content are computed and provided in the printed output.

This research examined four factors on the fermentation of xylose by Candida shehatae, and the following conclusions were reached: (1) A minimal medium is effective for producing ethanol. (2) Peptone and casamino acids stimulate ethanol production. (3) Aeration is important in obtaining good ethanol production rates and yields. (4) The maximal rate of ethanol production is attained around pH 3.2-3.4. Under the best conditions employed, C. shehatae ATCC 22984 produced up to 4% (w/v) ethanol from 20% xylose in four days. With 9% xylose, ethanol yields approximating 0.4 g/g xylose were obtained.

The potential for substitution of structural wood composites into solid-sawn lumber markets is presented from the technological viewpoint. Technological limitations of existing composite processes and products are reviewed in the context of the present laminated veneer lumber (LVL), flakeboard, and fiber/ paper industries. The limits of mechanical property potential are presented to show that strength and stiffness may be enhanced through innovative processing of structural wood composites. The routes for introduction of these composites are presented as (1) direct substitution for...

Decreasing size and quality of the world's forest resources are responsible for interest in producing composite wood structural components. Process and design optimization methods are offered in this paper. Processing concepts for wood composite structural products are reviewed to illustrate manufacturing boundaries and areas of high potential. Structural optimization principles are introduced to provide an overview of design requirements for various structural elements. An approach to the optimal design of a simple joist is presented. The approach allows the optimization for a variety of...

Changes in the composition of gum rosin during disproportionation in the presence of 5% palladium-on-charcoal have been determined by gas chromatography. The principal reaction product was dehydroabietic acid. The exocyclic vinyl group of the pimaric/isopimarictype resin acids was hydrogenated completely. Only a small amount of dihydroabietic acids was formed. Eight dihydro resin acids were identified. No tetrahydro resin acids were observed.

Over the past two decades U.S. lumber imports from the tropics have increased fourfold. Plywood trade, mostly from Asian sources, has soared fortyfold and now equals our domestic production. Log imports, though, have decreased drastically from about 100 million board feet (log scale) in the 1950's to 30 million currently. Much of the world timber trade now is in the form of processed material. A wide array of tropical wood species and species groupings are now available to U.S. processors. Many are already well known on the European markets. This surge in supplies from overseas includes...