Treesearch

The fungitoxic properties of four fungicides, alone and in combination, against four different mold fungi commonly associated with indoor air quality problems were evaluated on two different wood species and sheetrock. The fungicides were chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) (CTL) in a 40.4% aqueous dispersion, disodium octaborate tetrahydrate (DOT) in two different forms - a 40% glycol solution and a 98% wettable powder, and didecyl dimethyl ammonium chloride (DDAC) in an 80% solution. The fungi were Aspergillus niger, Cladosporium cladosporioides, Penicillium brevicompact...

In this paper we examine the effect of predictor sort sampling on one-sided confidence bounds for normal quantiles. We have found that standard noncentral T theory that ignores the predictor sort nature of the sampling leads to Ȳ − kS bounds that are overly conservative. On the other hand, maximum likelihood methods yield non-conservative bounds even for fairly large sample sizes. We provide an asymptotic result that yields the appropriate corrections for the standard noncentral T approach.

The primary means of inspecting buildings and other structures is to evaluate each structure member individually. This is a time consuming process that is expensive, particularly if sheathing or other covering materials must be removed to access the structural members. This paper presents an effort to use a low frequency vibration method for assessing the structural performance of wood floor systems.

Pulp and paper manufacturing constitutes one of the largest industry segments in the United States in term of water and energy usage and total discharges to the environment. More than many other industries, however, this industry plays an important role in sustainable development because its chief raw material— wood fiber—is renewable. This industry provides an example of how a resource can be managed to provide a sustained supply to meet society’s current and future needs. The objective of this work is to present streamlined environmental life-cycle assessments (LCA) between chemical...

At the joint meeting of the Western International Forest Disease Work Conference and the Western Forest Insect Work Conference, held in Bend, OR, on September 13, 1989, a symposium was convened entitled "Current Research on Wood-destroying Organisms and Future Prospects for Protecting Wood in Use. "Presentations were made by three pathologists and nine entomologists. At that time the taxonomy of wood-decay fungi was primarily based on morphology; new techniques using genetic and immunological tests were introduced. Nondestructive evaluation for detection of wood decay and presence of...

Western redcedar siding was "preweathered" by placing it outdoors for 1, 2, 4, 8, or 16 weeks prior to being painted. Panels were painted following the preweathering and tested for paint adhesion. The amount of time these panels were exposed (preweathered) directly affected paint adhesion. As much as 50% paint adhesion loss was shown for specimens preweathered for 16 weeks. For matching panels that were painted and exposed outdoors, the longer the panels were preweathered, the shorter the service life of the paint: The paint on panels preweathered for 16 weeks began to flake and peel after...

One of the more common areas of mineral scale formation in bleach plants is on washer face wires and the extraction rings of diffusion washers. Whereas most scale problems can be understood as a mixing of two streams that increase the concentrations of anions and cations and exceed a solubility product, washer problems are often more difficult to understand. The behavior of the pulp mat as a cation exchange resin makes these devices operate as an ion exchange column. This feature has the effect of delaying the release of cations into the filtrate and can cause a high concentration of a...

The anisotropy of wood creates a complex problem for solving heat and mass transfer problems that require analyses be based on fundamental material properties of the wood structure. Inputting basic orthogonal properties of the wood material alone are not sufficient for accurate modeling because wood is a combination of porous fiber cells that are aligned and mis-aligned in low- and high-density regions called annual rings. Modeling heat transfer requires the development of effective thermal conductivities as a function of those parameters associated with the rings. Effective 2D thermal...

A fiber model and simulation method are employed to investigate the mechanical response of planar fiber networks subjected to elongational deformation. The simulated responses agree qualitatively with numerous experimental observations. suggesting that such simulation methods may be useful for probing the relationships between fiber properties and interactions and the behavior of fiber networks. Quantitative discrepancies between experiments and simulations are attributed in pan to computational limitations, in addition to potential shortcomings in the underlying fiber model.

In order to circumvent the problem of altering the sheet composition to increase bonding, in this study the bonding was increased by wet pressing and press drying sheets to various levels of RBA. The operating regime problem was then studied by interpreting the tear relative to bonding (where bonding is measured as T/Z, Tensile index/Zero span tensile index) relationship in whole TMP, its fractions and mixtures of these fractions. In addition the effect of fiber length on the tear strength at various bonding levels was studied using the data obtained from the mixture studies.