Treesearch

Because much of our future timber resource is expected to come from short rotation plantations, we need to develop silvicultural practices that will improve the quality of the timber coming from these plantations. Short rotation plantations tend to produce timber with a higher percentage of juvenile wood, which has substantially lower mechanical property values than does mature wood. Measuring the microfibril angle (MFA) of wood gives important clues about the characteristics of the wood and can be used as a silvicultural tool to improve the quality of a plantation. In this report, we...

This review summarizes patents related to paper recycling that were issued during the first 6 months of 2001. Two online databases, Claims/U.S. Patents Abstracts and Derwent World Patents Index, were searched for this review. This semiannual feature is intended to inform readers about recent developments in equipment design, chemicals, and process technology for recycling paper and alternative products derived from post-consumer paper. Only brief summaries of individual inventions constitute this review. For more complete information, readers will need to access the full text of a specific...

The finite difference approximation is applied to estimate the moisture-dependent diffusion coefficient by utilizing test data of isothermal moisture desorption in northern red oak (Quercus rubra). The test data contain moisture distributions at discrete locations across the thickness of specimens, which coincides with the radial direction of northern red oak, and at specified times. Also, the rate of moisture variation at each specified time and location must be known or correctly estimated. The functional form of the diffusion coefficient as well as the boundary conditions at the...

In this review we primarily discuss our use of the oxygen consumption calorimeter (ASTM E1354 for cone calorimeter and ISO9705 for room/corner tests) and fire growth modeling to evaluate treated wood products. With recent development towards performance-based building codes, new methodology requires engineering calculations of various fire growth scenarios. The initial fire growth scenarios considered are those observed in 25-foot tunnel tests (ASTM E84) and room/corner tests to ensure continuity with existing building codes. We conducted specialized tests with the cone calorimeter to...

Although many enzymes can readily and selectively use oxygen in water--the most familiar and attractive of all oxidants and solvents, respectively–-the design of synthetic catalysts for selective water-based oxidation processes utilizing molecular oxygen remains a daunting task. Particularly problematic is the fact that oxidation of substrates by O2 involves radical chemistry, which is intrinsically non-selective and difficult to control. In addition, metallo-organic catalysts are inherently susceptible to degradation by oxygen-based radicals, while their transition-metal-ion active sites...

The TAMM/NAPAP/ATLAS/AREACHANGE(TNAA) system and the Forest and Agriculture Sector Optimization Model (FASOM) are two large-scale forestry sector modeling systems that have been employed to analyze the U.S. forest resource situation. The TNAA system of static, spatial equilibrium models has been applied to make SO-year projections of the U.S. forest sector for more than 20 years. Much of its input on forest management behavior and decisions about use of forestland derives from expert-based systems external to the TNAA system. FASOM, a spatial intertemporal optimization model, directly...

In the building community, there is a growing demand for high-performance, low-maintenance, and low-cost building products. To meet this demand, natural fiberthermoplastic composites are being used to produce such products as decking, window and door elements, panels, roofing, and siding. In spite of the rapid growth in the use of these composites, little is known about their fastener performance. In this study, experimental fastener tests were performed on wood flour-thermoplastic composite panels. Results are presented for screw withdrawal, nail withdrawal, nail head pull-through, and...

CCA-treated southern yellow pine (SYP) chips were remediated utilizing acid extraction alone, and using acid extraction followed by bioleaching with the metal-tolerant bacterium Bacillus licheniformis CC01. bCleanedc chips were used to make particleboard (PB) with 10 percent urea-formaldehyde (UF) resin, and the PB samples were evaluated for internal bond (IB), modulus of elasticity (MOE), modulus of rupture (MOR), thickness swell (TS), water absorption, and decay resistance. PB panels prepared from just acid-extracted chips and two-step remediated chips showed an average 22 and 28 percent...

A key to 13 species in the genus Hygrocybe subgenus Pseudohygrocybe section Firmae is provided for the Greater Antilles. Seven new species and one species that is a new report for the Greater Antilles are described. The new species are H. brunneosquamosa, H. cinereofirma, H. flavocampanulata, H. luboyi, H. miniatofirma, H. neofirma and H. olivaceofirma. The new report is H. trinitensis.

Although timber production has grown steadily over the last decade, information about the use of timbers and the corresponding resource remains in short supply. This study adds to the available literature on solid sawn timbers by compiling data on timber production and uses. The major categories of solid sawn timbers researched were railroad ties, timber bridges, and other transportation structures. The outlook seems relatively bright for railroad ties. The demand for wood railroad ties has grown with the railroad industry, and there is no reason to think that this demand will not continue...