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This report documents a simulation model of the plywood manufacturing process. Its purpose is to enable a user to make quick estimates of the economic impact of a particular process change within a mill. The program was designed to simulate the processing of plywood within a relatively simplified mill design. Within that limitation, however, it allows a wide range of options to be incorporated so as to customize the program to a variety of situations. The program should not be confused with a linear program-based optimization model. This program does not seek an optimum solution from a...

The concept of heat release rate is gaining acceptance in the evaluation of fire performance of materials and assemblies. However, this concept has not been incorporated into fire endurance testing such as the ASTM E-119 test method. Heat release rate of assemblies can be useful in determining the time at which the assemblies start to contribute to the controlled fire and the magnitude of heat contribution. Twelve wood wall assemblies were tested in an ASTM E-119 fire endurance furnace at the USDA Forest Service, Forest Products Laboratory. Heat release measurements using the oxygen...

This review critically evaluates literature on the ways in which excessive drying (overdrying) inactivates wood surfaces to bonding, primarily for phenolic adhesives. In Part I of a two-part review, three inactivation mechanisms involving physical responses to overdrying are considered: (1) exudation of extractives to the surface, which lowers the wettability or hides the surface; (2) reorientation of wood surface molecules, which reduces wettability or places for bonding; and (3) irreversible closure of large micropores in cell walls. I believe that extensive evidence from wood bonding...

A complete annotated bibliography of all published and unpublished reports of the USDA Forest Service, Forest Products Laboratory, on the subject of tropical woods. Research on tropical woods began soon after the formation of the Forest Products Laboratory in 1910 and continues today.

Xylose is a major component of angiosperm lignocellulosic residues. It is available from a number of different sources in the forest products industry, including fiberboard manufacture, sulfite waste liquors, production of dissolving pulp, and the hydrolysis of hardwood residues. Hydrolysis of wood for the production of liquid fuels, particularly ethanol, has been proposed and practiced at various times and especially during petroleum shortages such as those that occurred in World War II or the late 1970s and early 1980s.

Recently, we showed that a biomechanical pulping process in which aspen chips are pretreated with a white-rot fungus can give energy savings and can increase paper sheet strength. To optimize this process, we need more efficient ways to evaluate the fungal treatments. Here, we examine a method that consists of treating coarse refiner mechanical pulp, refining in a PFI mill, and testing for freeness. The relative ability of a fungus to promote a decrease in pulp freeness in the PFI mill did not correlate with its ability to give energy savings in chip refining. However, it correlated with...

To gain insight into the biochemical mechanism employed by brown-rot fungi to depolymerize cellulose, we identified the end-groups of chemically pure cellulose that had been depolymerized by the brown-rot fungus, Postia placenta. The acids identified include glyceric and erythronic, indicating oxidative cleavage of the vicinal dial carbon-carbon bonds within glucosyl residues in the cellulose polymer. Gluconic and arabonic acids were also identified as major products. No uronic acids were produced in either systems.

This study explains and determines fuelwood consumption at the county level based on county economic and demographic conditions, and identifies U.S. counties where potential fuelwood use problems and benefits are greatest. The percentage of wood-burning households in a county is estimated and multiplied by estimated average wood consumed per wood-burning household in that county to produce an estimate of total county fuelwood use. Use estimates are then compared to forest inventory data to identify potential problem/benefit areas. Parameters in estimating equations are determined from...

A room test designed according to the ASTM draft standard was used to investigate the effect of various parameters on the contribution of wall and corner fires to compartment fire growth. Location of the burner (against a wall or in a corner), power program of the gas burner ignition source, and combination of wall linings were varied, An initial series of calibration tests were conducted on ceramic fiber blanket and gypsum board. These tests showed satisfactory instrumentation, good repeatability, and reliable data reduction techniques. The second series were wall and corner tests with...

This report describes methods of predicting the performance of light-frame wood structures with emphasis on floor and wall systems. Methods of predicting structural performance, fire safety, and environmental concerns including thermal, moisture, and acoustic performance are addressed in the three major sections.