Treesearch

Present building codes and standards are a combination of specifications and performance criteria. Where specifications prevail, the introduction f new materials or methods can be a long, cumbersome process. To facilitate the introduction of new technology, performance requirements are becoming more prevalent. In some areas, there is a lack of information on which to base acceptable performance. As background information, existing major codes and standards were surveyed. Existing criteria are listed for each aspect of construction under major headings of structural and environmental. A...

There is a growing demand for natural exterior wood finishes that retain the original attractive appearance of wood with the least change in color and masking of grain. A number of experimental finishes are being evaluated for their performance in the cool, moist climate of Olympia, Wash. This study, started in 1966, has included observations on the weathering performance of 48 experimental finishes, both transparent and pigmented. Of these, 36 are still on exposure and inspected annually. Generally, water-repellent preservatives are the least durable of the natural finishes. Pentachlorophe...

EVALUE, a FORTRAN program, was developed to provide a framework for cash flow analysis of investment opportunities. EVALUE was designed to assist researchers in evaluating investment feasibility of new technology or new manufacturing processes. This report serves as user documentation for the EVALUE program. EVALUE is briefly described and notes on preparation of a data deck are provided. Sample program input, sample output, and a complete listing of the program are provided.

Paralabatia is a small genus of five or six species ranging from the Amazon to the West Indies. From the anatomical standpoint the genus as constituted by Aubréville forms a group of closely related species. In marked contrast the four species cited by Baehni belong to four different anatomical groups. The woods of Paralabatia are somewhat similar to those of Neoxythece but can be readily distinguished by the smaller pores and shorter vessel members characteristic of Paralabatia.

Chromolucuma was established by Adolpho Ducke in 1925 based on the single species rubriflora native to the middle Amazon of Brazil. A second species, baehniana, was described in 1949 by Monachino. It occurs in the Amazon and Guyana. A third species, sericea, was named by Gilly but it is not known at the present time whether this was validly published. Anatomically the affinities of Chromolucuma appear to be with Pouteria (sensu Aubréville) but it differs from the latter in several respects.

Reducing kiln-drying time for oak lumber can reduce energy requirements as well as reduce lumber inventories. In this work, l-inch northern red oak and white oak were kiln dried from green by a combination of individual accelerating techniques– presurfacing, presteaming, accelerated and smooth schedule, and high-temperature drying below 18 percent moisture content. Results were compared with those achieved by conventional kiln drying. Drying time in the combined techniques procedure was reduced by more than 50 percent. The results for quality of the lumber were mixed. In most of the...

The genus Elaeoluma consists of three species distributed in the Amazon Basin, Surinam, Guyana, and Venezuela. The description presented here is based on E. glabrescens of the Amazon Basin. The wood is easily differentiated from all other neotropical Sapotaceae by its pale brown color, reticulate parenchyma, which is hardly discernable with a hand lens, and a low specific gravity averaging 0.50. Whether the correct nomenclature is Elaeoluma or Gymnoluma is problematical and remains to be resolved by a monographer.

This paper considers laminated beams with layers of different isotropic or orthotropic materials fastened together by thin adhesives. The stresses that result from subjecting each component layer of the beam to different temperature or moisture stimuli which may also vary along the length of the beam, are calculated. Two-dimensional elasticity theory is used so that a wide range of problems, such as that of beams composed of layers of orthotropic materials like wood, can be studied, and accurate distributions of normal and shear stresses obtained. The stress intensity along the bearing...

Yellow-poplar was dried as 7/4 flitches at high temperatures and subsequently ripped into studs to meet National Grading Rule Standards for STUD grade. The effects of growth stresses in these flitches from smaller logs appear to be minimized by this process. Dry bulb temperatures from 235° to 295° F were explored in five drying trials. Best results were by drying for 28 hours at 235° F, followed by an equalizing period of 48 hours at 200° F and an equilibrium moisture content of 10 percent.

When bolts or timber connectors are used in a row, with load applied parallel to the row, load will be unequally distributed among the fasteners. This study assessed methods of predicting this unequal load distribution, looked at how joint variables can affect the distribution, and compared the predictions with data existing in the literature. Presently used design procedures were also assessed. The analytical methods were found to predict proportional limit loads but not joint strength.