Treesearch

The sapwood and heartwood extractives of Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] and the tall oil in the kraft black liquor were characterized. On pulping, isomerization and conversion of conjugated resin acids to dehydroabietic acid was observed. Recovery of both fatty and resin acids from pulping was lower than predicted from the extractive composition. Unusually high sterol esters and a new triterpene alcohol are reported. The lightwood-inducing effect of paraquat is limited.

Work in progress on prehydrolysis of white birch (Betula papyrifera) wood with sulfur dioxide presents an alternative means for producing a relatively concentrated pentose solution with a very small requirement for steam or other forms of energy. The key ideas are to conduct the prehydrolysis reaction at a very low liquor-to-wood ratio (called vapor-phase cooking in the pulp industry) and to obtain a relatively concentrated solution by countercurrently extracting the xylose, xylose oligomers, and other solubilized material from the reacted chips.

An American wood. Description of the distribution, growth, habit, wood, and wood properties of the species. Includes bibliographical references.

An American wood. Description of the distribution, growth, habit, wood, and wood properties of the species. Includes bibliographical references.

Six variations of a do-it-yourself solar collector design were constructed and exposed under stagnation conditions for 1 year; collectors were basically closed boxes without air circulation. Temperature in each collector was recorded throughout the test period and the effect of these temperatures on the wood framing and plywood in the collectors was estimated based on previous studies of effect of high temperature on properties of wood. Visual observations were also made on the wood, paint, insulation, and glazing. Temperatures in the collectors could reduce strength properties of the wood...

A reference source is provided for estimating the amount of heat energy that may be recovered using wood or bark fuel in typical furnace and boiler or hot air combustion heat recovery systems. A survey of reported data on higher heating values for various species of wood and bark fuels is provided. A set of formulas of a type commonly used by combustion technologists is also provided for estimating combustion system heat losses and net recoverable heat energy per pound of fuel as-fired, based on fuel higher heating value, moisture content, and excess air stack gas temperature, and ambient...

An assessment of available data and information describing the common carrier shipping environment was conducted. The assesment included the major shipping hazards of shock, vibration, impact, temperature, and humidity associated with the handling, transportation, and warehousing operations of typical distribution cycles. Previous environmental studies and current data are reviewed and assessed for applicability to general type cargo design and/or evaluation. The data for each hazard are summarized in a format considered most useful to packaging engineers when such data are available....

This report extensively reviews the chemistry of extractives from wood and bark of hardwoods from the eastern United States. While such extractives are not used to a great extent commercially, they may influence properties of the wood and performance of wood products. For example, extractives can protect wood from decay, add color and odor to wood, accent grain pattern, and enhance strength properties. Extractives may also inhibit setting of concrete, glues, and finishes; cause problems in papermaking; contribute to corrosion of metals in contact with wood; present health hazards, and...

Whole-tree chips deteriorate more rapidly than do clean, debarked chips and present a greater hazard for spontaneous ignition when stored in outdoor piles. To prevent ignition, the chips can be stored for only short periods of time and the frequent rotation of the storage piles results in high handling costs. Drying the chips prior to storage will prevent deterioration and heating, provided the chips are stored under cover. In many cases, the costs of drying can be recovered when the chips are burned for fuel. In these instances, drying and covered storage is the least expensive method for...

Evaluation, maintenance, and upgrading of timber structures is an area where little printed reference material exists. This paper covers the state-of-the-art on design, material properties, and construction procedures on older buildings. Some guidelines are presented on rehabilitating and upgrading timber structures, along with significant references.