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Early and accurate detection of the extent of fungal deterioration during forensic inspection of the building envelope would eliminate excessive or unnecessary replacement of wood-based building materials. Areas of water infiltration in wood-framed building envelopes in the Pacific Northwest were evaluated visually and sampled for moisture content. Wood samples were cultured in the laboratory and tested for the presence of decay fungi by the immunodiagnostic wood decay (IWD) test. In oriented strandboard sheathing, a correlation was seen between low moisture content, arrested fungal...

Ratios of strength properties of lumber are commonly used to calculate property values for standards. Although originally proposed in terms of means, ratios are being applied without regard to position in the distribution. It is now known that lumber strength properties are generally not normally distributed. Therefore, nonparametric methods are often used to derive property values. In some situations, estimating properties based on a parametric estimate is required. For these situations, the three-parameter Weibull distribution looks promising. To use this approach, procedures for...

Environmental concerns about preservative bleeding (or migrating) from timber bridges have increased in recent years. This preliminary study examined the creosote retention levels at six timber highway bridges in Michigan's lower peninsula during the summer of 2000. Several test core samples were removed from the bridge superstructures (four bleeders and two controls) and were evaluated for creosote content in the laboratory. Results from three of the four bleeder bridges indicated high creosote retention levels between 36 and 52 lb/ft3 (576.7 and 833 kg/m3) after several years in service.

A process was designed to evaluate the sustainability and potential marketability of USDA Forest Service patented technologies. The process was designed and tested jointly by the University of North Carolina, the University of Michigan, Partners for Strategic Change, and the USDA Forest Service. Two technologies were evaluated: a fiber-based product and a wood fiber/fiberglass composite technology. The results indicate several different ways in which the technologies might be exploited to produce new commercial products for both domestic and international markets, through licensing of the...

The study described in this report was conducted to examine the flexural properties of laminated veneer lumber (LVL) manufactured from red maple veneer. Ultrasonically rated veneer, which was peeled from low value red maple saw-logs, was fabricated into 1/2-in.-(1.3-cm-) and 2-in.-(5-cm-) thick LVL billets. The flexural properties of the billets and of corresponding small specimens cut from the billets were determined through flatwise and edgewise static bending tests. Ultrasonic wave propagation time and corresponding dynamic modulus of elasticity of red maple veneer were found to be well...

Peroxidase/H2O2-mediated radical coupling of 4-hydroxycinnamaldehydes produces 8–O–4-, 8–5-, and 8–8-coupled dehydrodimers as has been documented earlier, as well as the 5-5-coupled dehydrodimer. The 8–5- dehydrodimer is however produced kinetically in its cyclic phenylcoumaran form at neutral pH. Synthetic polymers produced from mixtures of hydroxycinnamaldehydes and normal monolignols provide the next level of complexity. Spectral data from dimers oligomers and synthetic polymers have allowed a more substantive assignment of aldehyde components in lignins isolated from a CAD-deficient...

Although wood was one of the earliest materials to be adhesively bonded, the factors that contribute to strong wood bonds are still not well understood. Wood is a very complex substrate in that it is non-uniform in most aspects. On the macro scale, it is a porous structure with different sized and shaped voids for fluid flow. The structural cells contain four different wall layers, and there is a middle lamella region between the cells. Each cell wall layer is made up of different amounts of three structural components: cellulose, mostly present as a crystalline and rigid polymer; hemicellu...

The unmitigated pest risk potential for the importation of unprocessed logs and chips of 18 species of eucalypts (Eucalyptus amygdalina, E. cloeziana, E. delegatensis, E. diversicolor, E. dunnii, E. globulus, E. grandis, E. nitens, E. obliqua, E. ovata, E. pilularis, E. regnans, E. saligna, E. sieberi, E. viminalis, Corymbia calophylla, C. citriodora, and C. maculata) from Australia into the United States was assessed by estimating the likelihood and consequences of introduction of representative insects and pathogens of concern. Twenty-two individual pest risk assessments were prepared,...

We made a series of aspen fibre medium density fibreboard panels adding various levels of chicken feather fibre to determine the relative effect of the feather fibre-wood fibre mixtures on composite panel properties. Chicken feathers are a waste product left over after processing chickens for meat. The feather fibre amounts used ranged from 20% to 95% and a 5% concentration of phenol formaldehyde resin was used as the adhesive. The panels were tested for mechanical and physical properties as well as decay. Initial mechanical properties show some loss in strength and stiffness for feather...

The objective of this research was to develop a stable process for compound ultra-pure cellulose fibers into polyamides. This has been a difficult procedure and has taken years of trial and error to understand the viscosity shear heating effects associated with compounding cellulose into high-melting point engineering thermoplastics. The evolution of the low temperature compounding (LTC) technique is ongoing, and the ongoing development of new process stabilizers for cellulose-polyamide composites will help facilitate the commercial use of these new materials for industrial applications.