Treesearch

A previous study (Simpson and others 1998) showed that maple could be kiln dried successfully for structural uses by a schedule that was accelerated in comparison with the traditional maple schedule intended for products where appearance is important, such as furniture. In addition to being unnecessarily conservative and slow for lumber intended for structural uses, the traditional maple schedule is controlled on the basis of moisture content. Changes in kiln conditions are made when the lumber reaches certain levels of moisture content; this requires some method of estimating moisture...

Condition assessment is an important first step in the restoration of any historic structure. Immunodiagnosis of wood decay fungi, nondestructive evaluation (NDE) stress wave mapping, and compression perpendicular to grain were used to evaluate white pine roof truss timbers from the Blacksmith Shop of the Quincy Mining Company in Keweenaw National Historical Park. Immunodiagnosis indicated that areas in the timber had been exposed to decay fungi. Stress wave NDE mapping located voids in the timbers tested. Compression perpendicular to the grain correlated with NDE findings.

In situ polymerization of bioactive monomers was investigated as an alternative to conventional preservative treatments. The results are presented in a series of two papers. In Part 1 of the study, six acrylate monomers with covalently bonded, potentially bioactive moieties were synthesized: (1) pen-tachlorophenolyl acrylate (PCPA), (2) tributyltin acrylate (TBTA), (3) 8-hydroxyquinolyl acrylate (HQA), (4) 5,7-dibromo-8-hydroxyquinolyl acrylate (DBHQA), (5) diethyl-N1N-bis(acryloxyethy1) aminomethyl phosphonate (Fyrol 6 acrylate, F6A), and (6) tetrabromobisphenol A acrylate (TBBPAA). All...

This paper is the second in a two-part series on in situ polymerization of bioactive monomers as an alter-native to conventional preservative treatments. In this part of the study, bioactive monomers were eval-uated for their ability to provide resistance to decay and protection against fire. Five bioactive monomers were synthesized: (1) pentachlorophenolyl acrylate (PCPA), (2) tributyltin acrylate (TBTA), (3) 8-hydroxyquinolyl acrylate (HQA), (4) 5,7-dibromo-8-hydroxyquinolyl acrylate (DBHQA), and (5) diethyl-N1N-bis (acryloxyethyl) aminomethyl phosphonate (Fyrol 6 acrylate, F6A)....

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...