Treesearch

This review focuses on the feasibility of acoustic emission (AE) and acousto-ultrasonic (AU) techniques for monitoring defects in wood, particularly during drying. The advantages and disadvantages of AE and AU techniques are described. Particular emphasis is placed on the propagation and attenuation of ultrasonic waves in wood and the associated measurement problems. The review is divided into two sections, acoustic emission techniques and acousto-ultrasonic techniques. It includes historical background on the techniques as well as applications for wood and wood products. Because much...

The suitability of modified bark or wood fiber derived from southern yellow pine to function as P sorbents was investigated. Sorbent preparation process included grinding, size fractionation] extraction for surface activation] and treatment with polyallylamine hydrochloride (PAA HCI) or 3-chloro-2-hydroxypropyltrimethlyammonium chloride. SEM images revealed surface morphology changes of these fibers due to extraction and chemical treatment. A greater than 200% increase in N content of PAA-bark compared to control (extracted bark) together with the appearance of a strong CI peak in the EDXA...

Colloidal stickies that build up in mill process water during pulping are problematic and difficult to remove. We examined precipitated calcium carbonate (PCC) as a means to ameliorate process water stickies. The effectiveness of PCC added directly into a slurry of deinked pulp was compared with in situ precipitation of PCC by the fiber loading method. We found that without retention aids, fiber loaded PCC resulted in the greatest attraction of colloidal stickies to pulp following high- consistency refining required for fiber loading. Also, without retention aids, fiber loaded PCC was the...

In order to insure a continuous supply of natural agricultural resources, management of the agricultural producing land should be under a proactive system of land management whose goal is both sustainable agriculture and the promotion of healthy ecosystems. Ecosystem management is not a euphemism for preservation, which might imply benign neglect. Sustainable agriculture denotes a balance between conservation and utilization of agricultural lands to serve both social and economic needs, from local, national and global vantage points. Sustainable agriculture does not represent exploitation...

The purpose of this chapter is to discuss forestry implications of SRWC based on an economic analysis. As with the development of paper recycling, anticipating forestry implications of agricultural SRWC will depend in part on anticipating market conditions and economic impacts of technological developments. This chapter presents an analytic framework and market outlook for agricultural SRWC as wood fibre crops in the USA and considers some potential implications for forestry.

Fourteen collections of resupinate higher fungi in the order Aphyllophorales (Basidiomycetes) were made on Subantarctic Macquarie Island (54°30'S, 158°57' E) in 1995. Of the 14, three proved to lack species-determining characteristic basidiospores and 12 were determined to belong to three species in two genera; Athelopsis lembospora (Bourdot)Oberwinkler, Athelopsis subinconspicua (Lirschauer) Julich, the first report of this species from the Southern Hemisphere, and Epithele galzinii Bres., the first reportr of E. galzinii from an Australian territory and also representing a southern range...

We have reported the use of polyoxometalates (POMs) as selective, regenerable delignification agents that are inherently thermodynamically stable, and self-buffering. The re-activation with oxygen is under conditions that mineralize the organic byproducts of the delignification process. Thus, the POMs provide the basis for a closed bleach plant wherein the consumable oxidant is oxygen and the primary byproducts are carbon dioxide and water. They have been shown to reduce the kappa levels of softwood kraft pulps from 30 to below 5 while retaining viscosity above 20. Recently we have...

Previous study indicated that the natural chemical constituents of the guayule plant (Parthenium argentatum) improved some durability properties of wood when it was treated with resin extracted from guayule. At present, there are about a dozen species of Parthenium growing in the North American continent. P. argentatum is the only species with harvestable amounts of the rubber latex. Other species such as P. incanum and P. tomentosum produce primarily resinous materials, but which could be as useful as the P. argentatum species for making composites. The predicted commercialization of...

Cranberry growers are concerned about the quality of water discharged from cranberry bogs into receiving surface waters. These water discharges may contain traces of pesticides arising from herbicide, insecticide or fungicide applications. They may also contain excess phosphorus from fertilizer application. Some cranberry farms have holding ponds to reduce the amount of pesticide or phosphorus in the discharged water from the bogs before release into receiving surface waters. Most farms can manage water and hold it on the marsh to reduce and or eliminate residues. However, where holding...

The ultimate goal of the US Postal Service (USPS) Environmentally Benign Stamp Program is to develop stamp laminates, i.e., face paper, adhesive and siliconized liner, that do not cause difficulties in recycling mills. The criterion for success, and the USPS definition of benignity, is the avoidance of process and product quality hardships when such PSA laminates are introduced in significant quantities. However, since it is neither prudent nor cost-effective to test experimental adhesive materials at mill scale, we have developed laboratory scale (360 g pulp) and pilot-scale (112 kg pulp)...