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The objective of this study was to investigate the influence of the phenol-formaldehyde resin content level (3 percent and 7 percent), and three fungi species (Poria placenta, Gleophyllum trabeum, and Polyporus versicolor) on the dimensional stability and decay resistance of high density composition boards made from plantation-grown southern pine chips. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that...

The development of grade standards for recycled timber and lumber will aid in reclaiming the value of wood.

To enhance appearance, stains are often sprayed onto western hemlock (Tsuga heterophylla (Raf.) Sarg.) lumber prior to treatment with chromated copper arsenate (CCA-C). Recently, concerns have increased that prestaining may affect the rate of leaching of CCA-C components from the treated wood and that leaching data generated with prestained material may not reflect the rate of release from nonstained wood. A secondary concern is that copper naphthenate field treatments applied to wood exposed during construction may contribute to the amount of copper released from CCA-C-treated structures....

Published spectroscopic observations pertaining to the crystal structure of native celluloses are reviewed for the purpose of defining our current level of understanding about crystalline polymorphism in these materials. Emphasis is placed on observations from solid state 13 C nuclear magnetic resonance (NMR), which first led to the postulate that most native, semicrystalline celluloses are composites of two crystalline allomorphs, labeled I a and I b . Historical background is presented, highlighting the structural controversies which mainly arose because different native celluloses were...

The concept of land expectation value developed by Martin Faustmann may serve as a paradigm for outcome-based performance measures in public forest management if the concept of forest equity value is broadened to include social and environmental benefits and costs, and sustainability. However, anticipation and accurate evaluation of all benefits and costs appears to present significant challenges, as revealed in the history of public forest policy in the United States. While public forest managers are unlikely to adopt performance measures based on forest equity value, an understanding of...

Ultrafiltration was investigated as a means to remove flexographic ink pigments from wash filtrate effluent generated from various mixtures of flexographic and offset old newspapers from deinking operations. Membrane separation efficiency was assessed from permeate flux, fouling rate, and ease of membrane regeneration (cleaning). Ultrafiltration was capable of completely removing ink pigments from effluent streams. Permeate flux decreased significantly with time due to membrane fouling and concentration polarization. Flocculation by acidification of the flexographic ink of effluents...

This study was carried out to determine the potential of coagulation pretreatment with organic or inorganic coagulants to improve ultrafiltration performance during processing of wash deinking effluents containing flexographic inks. Wash filtrate effluents generated from mixtures of old flexographic and offset newspapers and old magazines were pretreated with a cationic coagulant and alum before ultrafiltration. Membrane performance was assessed from permeate flux, fouling rate, and ease of membrane regeneration. Coagulation pretreatment of wash filtrate effluents with a commercial...

This review summarizes patents related to paper recycling that were issued during the first 6 months of 1999. The two on-line databases used for this search were C1aims/U.S. Patents Abstracts and Derwent World Patents Index. This semiannual feature is intended to inform readers about the latest developments in equipment design, chemicals, and process technology for recycling paper. This review contains only brief summaries of the inventions. For complete information, readers will need to access the full texts of specific patents. We organized this review into the following broad categories...

Connections between steel side plates and white oak glued-laminated beams subjected to tension perpendicular-to-grain stresses were tested to failure. The beams were then repaired with five different configurations using two sizes of lag screws, with and without steel reinforcing plates. The repaired beams were re-tested to failure. Results indicate that in all cases the repaired beams had greater ultimate loads than did the original beams. Results also indicate that lag screws without the reinforcing plate are sufficient for repair.

A new delignification technology based on the use of polyoxometalates (POMs) as delignification agents is under development at the USDA Forest Service, Forest Products Labotatory (FPL), in Madison, Wisconsin. These reagents are chlorine free and can be used under conditions wherein they oxidize lignin and chromophores in wood pulp fibers while leaving the cellulose undamaged. Their promise is enhanced by the fact that they can be re-activated with oxygen under conditions that result in oxidation of the organic byproducts of the delignification process. Thus, they can be continuously...