Treesearch

Research at the USDA Forest Service, Forest Products Laboratory (FPL) is being conducted to identify the compounds emitted from wood products during their manufacture and subsequent use. The FPL researchers are measuring the types and quantities of VOCs that are emitted from particleboard and MDF products to provide quantitative emissions information. This information can be used by other researchers studying indoor air quality of homes and offices where these products are used. The FPL researchers are also evaluating emissions during the manufacture of various composite wood products....

A rare find of Calocybe cyanea from Puerto Rico is described and illustrated. A discussion of all species of Calocybe found in the Caribbean is provided. Since nearly one-half of the described species of Calocybe can be found in the Neotropics (nine out of the 20 or so known taxa), a key to the species of Calocybe which are found in the Neotropics is included.

The degradation of wood by decay, fire and UV constitutes the three major losses of wood products in use. Commercial wood preservatives including chromated copper arsenate(CCA) and pentachlorophenol(penta) can only protect wood from decay. Dual protections of wood against decay and fire or decay and UV if acheivable are more desirable. Many phosphorus and boron compounds posses fire retardant and decay resistant properties. In our previous investigation, we found that wood reacted with phosphoramides produced in situ by reacting phosphorus pentoxide with amines was able to protect wood...

Charring rates for large-section timber based on experimental data have been generally established. The established rates may not be appropriately used for the prediction of failure times of lumber members which are small by comparison. It is questionable whether a constant rate can be safely assumed for lumber members since the rate is likely to increase once the centre-point temperature of the members stats to rise. This paper presents an empirically based model of charring rates for Spruce-Pine-Fir (SPF) Machine-Stress-Rated (MSR) 2 × 4 lumber subject to a constant-temperature exposure...

Adhesive bonding of wood components has played an essential role in the development and growth of the forest products industry and has been a key factor in the efficient utilization of our timber resource. The largest use of adhesives is in the construction industry. By far, the largest amounts of adhesives are used to manufacture building materials, such as plywood, structural flakeboards, particleboards, fiberboards, structural framing and timbers, architectural doors, windows and frames, factory- aminated wood products, and glass fiber insulation. Adhesives are used in smaller amounts...

In the living tree, wood contains large quantities of water. As green wood dries, most of the water is removed. The moisture remaining in the wood tends to come to equilibrium with the relative humidity of the surrounding air. Correct drying, handling, and storage of wood will minimize moisture content changes that might occur after drying when the wood is in service and such changes are undesirable. If moisture content is controlled within reasonable limits by such methods, major problems from dimensional changes can usually be avoided. The discussion in this chapter is concerned with...

In this research, an investigation on the mechanical behavior of corrugated board has been performed using finite element analysis. Numerical finite element models for corrugated board geometries have been created and executed. Both geometric (large deformation) and material nonlinearities were included in the models. The analyses were performed using the commercial nonlinear finite element code ABAQUS executed on Sun SparcStations and the State of Alabama Cray C90 Supercomputer. Both in-plane and transverse loadings of corrugated board configurations have been examined. The models...

During the past century, millions of structures were built from sawn lumber and timber. When these structures reach the end of their service lives, contemporary practices emphasize landfill disposal. In recent years, the public has expressed a strong interest in developing environmentally acceptable and efficient reuse options for this solid-wood material. As a result of this interest, a test program was developed to evaluate the grades and engineering properties of nominal 2-by 10-inches (standard 38- by 236-mm) lumber collected from the Twin Cities Army Ammunition Plant and compare this...

Bridge railing systems in the United States have historically been designed based on static load criteria given in the AASHTO Standard Specifications for Highway Bridges. In the past decade, full-scale vehicle crash testing has been recognized as a more appropriate and reliable method of evaluating bridge railing acceptability. In 1989. AASHTO published the Guide Specifications for Bridge Railings, which gave the recommendations and procedures to evaluate bridge rails by full-scale vehicle crash testing. In 1993, the National Cooperative Highway Research Program (NCHRP) published Report...

Design criteria are needed specifically for portable bridges to insure that they are safe and cost effective. This paper discusses different portable bridge categories and their general design criteria. Specific emphasis is given to quantifying the effects of dynamic live loads on portable bridge design. Results from static and dynamic load tests of two portable timber bridges showed that dynamic loads can be significantly greater than static loads. Under smooth bridge entrance conditions, the mean dynamic bridge deflections were 1.13 times greater than static bridge deflections. Under...