Treesearch

This research program is developing and evaluating potential value-added uses for a variety of exotic invasive woody species, such as salt cedar (Tamarisk spp.), one-seed juniper (Juniperus monosperma), and eastern red- cedar (Juniperus virginiana). Because each of these species is encroaching into America's natural indigenous ecosystems, land managers need tools to off-set the costs to control or eliminate them. In most cases, exotic- invasive species are removed from rangeland by using bulldozers and chains, piled and then burned. Such harvesting and burning in itself has significant...

A detailed understanding of wood cell wall structure and organization is important from both fundamental and practical point of views. A state-of- the-art 633-nm laser based confocal Raman microscope was used in situ to investigate the cell wall organization of black spruce wood. Chemical information on lignin and cellulose from morphologically distinct cell wall regions was obtained and Raman images of their distribution were generated. The initial findings were that lignin and cellulose concentration in tracheid cell walls differed significantly both within and between the distinct...

Fermentation residues (consisting of incompletely fermented fiber, adherent bacterial cells, and a glycocalyx material that enhanced bacterial adherence) were obtained by growing the anaerobic cellulolytic bacteria Ruminococcus albus 7 or Clostridium thermocellum ATCC 27405 on a fibrous fraction derived from lucerne (Medicago sativa L.). The dried residue was able to serve as an effective co-adhesive for phenol– formaldehyde (PF) bonding of aspen veneer sheets to one another. Testing of the resulting plywood panels revealed that the adhesive, formulated to contain 30% of its total dry...

While cellulosic and lignocellulosic materials have been studied using conventional Raman spectroscopy, availability of near-infrared (NIR) Fourier transform (FT) Raman instrumentation has made studying these materials much more convenient. This is especially true because the problem of laser-induced fluorescence can be avoided or minimized in FT- Raman (NIR Raman) spectroscopy. More recently, the method has also been used to generate quantitative results in cellulosic and lignocellulosic materials. Although linear dependence of Raman intensity on analyte concentration is well established,...

The multiple layer structure of oriented strandboard (OSB) has a significant influence on its performance, including thickness swell (TS). TS is recognized as an important performance property for OSB products. Optimization of TS through layer property ma- nipulation to achieve the lowest total TS while maintaining acceptable mechanical properties is attainable if the influence of OSB panel parameters on layer TS is known. In this study, the effect of wood species, resin type, and vertical density profile (VDP) on the total and layer TS were examined. Results from a small sample of...

The flammability of living vegetation is influenced by a variety of factors, including moisture content. physical structure and chemical composition. The relative flammability of ornamental vegetation is of interest to homeowners seeking to make their homes ‘fire safe’. The relative importance of the factors influencing fire behaviour characteristics, such as flammability, is unknown. In the present study, oxygen consumption calorimetry was used to obtain selected combustion characteristics of ornamental vegetation. Peak heat release rate, mass loss rate, time to ignition and effective...

Wood-plastic lumber is promoted as a low-maintenance high-durability product. After weathering, however, wood-plasticcomposites (WPCs) often fide and lose mechanical properties. In the first part ofthis study, 50%wood-flour-filled high-density polyethylene (HDPE) composite samples were injection molded or extruded. Composites were exposed to two accelerated weathering cycles in a xenon-arc type weathering apparatus; either ultraviolet (UV) light only or UV light and water spray. The composites lightened less when they were exposed to only UV light compared with exposure to UV light and...

The term “wood flour” is somewhat ambiguous. Reineke states that the term wood flour “is applied somewhat loosely to wood reduced to finely divided particles approximating those of cereal flours in size, appearance, and texture”. Though its definition is imprecise, the term wood flour is in common use. Practically speaking, wood flour usually refers to wood particles that are small enough to pass through a screen with 850-micron openings (20 US standard mesh). Wood flour has been produced commercially since 1906 and has been used in many and varied products including soil amendments,...

The term “natural fibers” covers a broad range of vegetable, animal, and mineral fibers. However, in the composites industry, it usually refers to wood fiber and agrobased bast, leaf, seed, and stem fibers. These fibers often contribute greatly to the structural performance of the plant and, when used in plastic composites, can provide significant reinforcement. Below is a brief introduction to some of the natural fibers used in plastics. More detailed information can be found elsewhere. Although natural fibers have been used in composites for many years, interest in these fibers has waned...

In order to elucidate changes occurring in lignin during polyoxometalate delignification of kraft pulp, residual lignins of a series of POM- delignified kraft pulps of decreasing kappa number were isolated and characterized. Oxidative treatment of commercial unbleached kraft pulp was performed using complex POM solutions containing the active [SiVW11O40]anion. For comparison, oxygen delignification of the same kraft pulp was also performed. It was observed that POM-delignification results in lignin which is more closely associated with carbohydrates/glucose, especially in the early phase...