Treesearch

This review summarizes patents related to paper recycling issued during the last 6 months of 1998. The two online databases used for this search are Claim/US. Patents Abstracts and Derwent World Patents Index. This semiannual feature is intended to inform readers about the latest developments in equipment, chemicals, and technology in the field of paper recycling. This review contains only brief summaries of the inventions. Readers will need to access the full texts of specific patents for complete information. We have organized this review into the following broad categories of recycling:...

A review of market history shows that southern pine sawtimber stumpage prices have increased by over 150 percent in this decade (Timber Mart South). Concurrently, some (i.e. Cubbage and Abt (1996) Nilsson et al (1999)) have questioned the adequacy of southern timber supplies to meet projected demands, which are projected to increase by about 25 percent over the next two decades. Given what we know about inventories and growth rates, what are the prospects for supplies to meet the needs of the southern pine industry?

To improve the overall performance of wood-plastic composites, appropriate technologies are needed to control moisture sorption and to improve the interaction of wood fiber with selected hydrophobic matrices. The objective of this study was to determine the surface thermodynamic characteristics of a wood fiber and to correlate those characteristics with the fiberas water vapor adsorption behavior. The surface thermodynamic properties, determined by inverse gas chromatography at infinite dilution or near zero surface coverage, were the dispersive component of the surface energy, surface...

Ultrafiltration is a potentially viable method of removing finely dispersed flexographic pigments from the deinking water loop. This work examines the effects of surface-active materials on ultrafiltration efficiency. A logarithmic relationship between permeate flax and pigment concentration was demonstrated at ink concentrations above 0.4%, permeation rates becoming independent of ink content at lower concentrations. The pressure independent ultrafiltration permeation rates observed at more highly concentrated ink dispersions were shown to be limited by mass-transfer effects, as predicted...

Three types of adhesives, urea-formaldehyde (UF) resin, phenol-formaldehyde (PF) resin, and polymeric methylene bis(phenyl isocyanate) (pMDI), were used for investigating the effect of pressing variables on volatile organic compound (VOC) emissions. The variables examined included press temperature and time, mat moisture content and resin content, and board density. The VOCs emitted during particleboard hot-pressing with Southern Pine furnish were collected with two scrubbers filled with water and methylene chloride, respectively. The water solution of emissions trapped in the first...

Alkyd-, oil-modified-latex-, and latex-based finishes were applied to severely weathered western redcedar and redwood boards that did not have any surface treatment to ameliorate the weathered surface prior to painting. Six finishes were evaluated annually for 11 years for cracking, flaking, erosion, mildew growth, discoloration, and general appearance. Low-solids- content latex finishes that contained about 10% raw linseed oil and 11% acrylic resin (i.e., the oil-modified latex finishes) performed better on badly weathered wood than did the alkyd and the other latex finish, even after 11...

Sustainable development has become the umbrella objective for forest management in many countries of the world, and managers are increasingly faced with the challenges of balancing environmental and economic health in their forest management and resource utilization decisions. It can no longer be assumed that abundant raw materials are available simply for the taking. As we enter the next century, a key question is where will we find the wood needed for shelter, fuel, transportation needs, and a host of other durable and nondurable goods? Wood will continue to be a staple of human society...

An experimental study was conducted to evaluate the residual shear capacity of large Douglas-fir timbers used in a military facility in Ardeen Hills, MN. A S-point and 4-point bending test was used to determine the effects of checks and splits on the shear strength capacity. Experimental results are compared to past shear and flexural studies.

This guide was prepared to assist inspectors in the use of stress wave timing instruments and the various methods of locating and defining areas of decay in timber bridge members. The first two sections provide (a) background information regarding conventional methods to locate and measure decay in timber bridges and (b) the principles of stress wave nondestructive testing and its measurement techniques. The last section is a detailed description of how to apply the field use of stress wave nondestructive testing methods. A sample field data acquisition form and additional reference...

Our understanding of the molecular architecture of intact, native plant cell walls is very limited. Traditional methods of investigation disturb the tissue to varying degrees and conclusions based on these methods may be intimately related to the technique used. A promising new technique to study native-state organization is polarized Raman spectroscopy. In this present work the macromolecular orientation and compositional variability for both cellulose and lignin in latewood cell walls of loblolly pine tracheids were investigated using Raman spectroscopy. This study has provided direct...