Semi chemical pulping processes, using both acid and neutral sulfite liquors, were ap!)lied to the following six Arkansas Delta hardwoods: black willow, southern cottonwood, American elm, sugarberry, green ash, and bitter pecan. Pulping conditions for yields of 75 to 80 percent were determined and the properties of both the pulps...
A method is described to determine the distribution of the bending stresses in a wood beam when some of these stresses exceed the proportional limit. This is used to calculate the position of the neutral axis and the bending strength of some Douglas-fir beams. The calculated values agreed with the...
Hardwoods, including aspen, comprised 22 percent of the pulpwood. received in the New York and New England States pulp mills in 1944 when war-time conditions favored the use of all available wood. The denser hardwoods alone, however, amounted to only 9 percent of all the pulpwood, and this value is...
This symposium was arranged and conducted in cooperation with the Research and Products Committee of the National Lumber Manufacturers Association, 1319 Eighteenth St., N.W., Washington 6, D.C. The purpose was to bring together a group of approximately 100 individuals broadly representing various phases of the wood industry, the present wood...
The mold resistance of fiberboard has been studied to provide a basis for recommendations on the relative merits of various types of commercial and of experimental fiberboards. The experimental fiberboards were prepared. by the Division of Pulp and, Paper of the Forest Products Laboratory.
A major objection to lumber shipped green is that it may be damaged by wood-attacking fungi, either in transit or soon after it is put into use. The chance for such damage can be greatly decreased by dipping the lumber in a toxic solution at the sawmill.
Blue stain and...
The breaking radii of variously discolored veneers of six different hardwood species were small enough, for most of the discolorations, to indicate that such veneers can be used successfully on members having curved surfaces. When expressed in terms of the minimum radius of curvature attained without fracturing, the breaking radius...
A survey was made in Oregon and Washington of the discoloration occurring in noble fir and Western hemlock wood, and the present data are presented as an aid in the inspection of these woods for aircraft and other high-grade lumber.
Recommendations, based on strength tests of similar discolorations in spruce...
Wood joints properly made with protein glue should last indefinitely under dry conditions. However, under moist conditions some glues are subject to the actions of micro-organisms and chemical hydrolysis. In previous work the action of bacteria has been discounted as the cause of delimitation of casein glued plywood in the...
A survey was made of the discolorations occurring in Sitka spruce wood, and toughness tests were made on specimens that included discolorations of unknown or doubtful significance.
Intelligent selection of wood for the job it is to do is particularly essential during wartime conditions of scarcity when supplies must be conserved and useful life extended. One way of increasing the service life of wood exposed to damp conditions is to select material that has a high natural...
No one prefers green lumber. Its higher shipping weight, poorer nail-holding power, and shrinkage after fabrication are well known, but the present pressure for deliveries results in much of it being accepted. Another major objection to lumber shipped green is that is may be damaged bu wood-decaying fungi, either in...
American beech (Fagus grandiflora) is now, and probably will be, increasingly used to replace yellow birch for aircraft construction. Even though it is one of the principal components of the northern hardwood forests of North America, study of the characteristics and properties of its wood has been neglected to the...
The rat caused by Pozia incrassata (Berk, and Curt.) Burt (sometimes erroneously called "dry rot") in individual cases is the most destructive of the building decays in the warm coastal portions of the United States and the South. The fungus usually attacks rapidly and may cause damage necessitating extensive repairs...
Dipping or spraying green lumber with stain control chemicals has been reported recently as valuable for delaying or preventing stain and decay infection in bulk-piled lumber, as well as in the air-seasoning piles for which such treatments were originally developed. But it should be kept in mind that if lumber...
This symposium dealt primarily with one important aspect of wood quality, namely specific gravity as determined in standing timber by the increment core sampling method. It covered the status of research in this area, the importance of the work, present and potential uses for wood density data, and the need...
Summarizes information on wood as an engineering material.
Presents properties of wood and wood-based products
of particular concern to the architect and engineer. Includes
discussion of designing with wood and wood-based products
along with some pertinent uses.
The synthetic-resin glues, or simply resin glues, were introduced as woodworking glues about 1935, but their development and acceptance on a large scale began during World War II and is still increasing. These resin glues are products of the modern chemical industry and originate from raw materials derived from coal,...