We have developed a method for the determination of the orientational distribution function of partially ordered systems from the EPR line shape that is an alternative to the usual one of expansion in the elements of the Wigner rotation matrices. The method can be applied to distribution functions whose expansion...
We have developed a method for determining the response of a static, partially ordered ensemble of molecules to various types of electromagnetic probes. In our formalism a physical model is constructued for the orientational distribution function, which is represented as a volume integral over a set of weighting functions. Procedures...
We have developed a new approach to the theory of linear dichroism in partially ordered systems. The description of the partially ordered ensemble uses a density of states function, D(θ, ϕ, Δ), which gives the probability that the direction of polarization for incident polarized light has spherical angles θ and...
We report Monte Carlo simulations of the dynamics of intramolecular contact in alkane chains and in end‐labeled alkane chains. The chain is confined to a diamond lattice except during conformational jumps. Rotational jumps around internal bonds provide the mechanism for change in the end‐to‐end separation but crankshaft‐like motions of the...
We have expanded on the results of an earlier paper [J. Chem. Phys. 72, 221 (1980)] which deals with a method for determining the response of a static, partially ordered ensemble of molecules to various types of electromagnetic probes. In this paper we consider types of spectroscopy whose response depends...
A single‐photon timing system is described which is capable of extracting fluorescence lifetimes as short as 25 ps. The system is an improved version of an earlier apparatus. The new system uses a synchronously pumped, mode‐locked dye laser with 10‐ps pulses operating at 82‐MHz repetition rate. A fast photodetector and...
The bioassay with Aspergillus niger is a simple way of determining the presence and amount of pentachlorophenol or tributyltin oxide in wood, but it does not appear useful for measuring strongly fixed chemicals such as chromated copper arsenate, borate, and fluoride. Its effectiveness in detecting other preservatives has not been...
A closed-tube bioassay with Poria placenta was used to measure residual fungistatic vapors in wood fumigated with methylisothiocyanate (MIT). This bioassay showed an inverse linear relationship between fungal growth and the amount of MIT in the wood samples. For fumigated increment-core sections of unseasoned Douglas-fir heartwood (4.8 mm in diameter...
Heartwood from coastal redwood [Sequoia sempervirens (D. Don.) Endl.] is very durable and is often used untreated in harsh environments, such as cooling towers of power or chemical processing plants. Wood in this environment is often attacked by soft rot fungi. Some wood users attempt to bolster protection by including...
Alder represents an abundant but underutilized resource that has little natural resistance to decay. Treated alder might be used for stakes, posts, or other nonstructural applications. The performance of alder treated with chromated copper arsenate (CCA), copper 8 quinolinolate, zinc naphthenate (ZN), or thiocyanomethylthiobenzothiazole (TCMTB) was assessed in soil block...
Mylone@ and tridipam are two solid chemicals that decompose to produce methylisothiocyanate (MIT), a highly effective wood fumigant. In this study, two techniques -- a rapid, test-tube method and small-scale, wood-block assay -- were used to determine the effect of the pH of various chemical buffers on the decomposition of...
A small-scale test was developed to evaluate the ability of fungicides to control decay fungi established in wood. The test, which uses blocks 2.5 x 2.5 x 10 cm, tests the ability of a chemical to migrate from the middle of the block to control a previously established decay fungus,...
The influence of moisture content (MC) and conventional preservative treatment on methylisothiocyanate (MIT) sorption and diffusion were investigated in Douglas-fir wood. In wood at 0% MC, the ratio of equilibrium MIT adsorption to desorption concentrations was low (0.2), but it increased rapidly to about 0.94 above 18% MC. Partition coefficients...
A procedure has been developed to optimize designs of metal-clad post-frame buildings using an expert system. The novel part of the study is the development of a procedure that extends the solution of an engineering problem from a conventional algorithmic Computer Aided Design (CAD) program to be used by the...
High concentrations of the fumigant methylisothiocyanate (MITC) will effectively control decay fungi in large wood structures, but the fungitoxicity of low MITC concentrations and the influence of wood moisture content (MC) on its performance are not well understood. The MC of Douglas-fir heartwood greatly influenced the susceptibility of the decay...
Vapam(r) (NaMDC) is the fumigant most commonly used to arrest and control decay of utility poles. While volatile fungitoxins are detectable only 1 to 2 years after treatment, poles treated with Vapam(r) remain free of decay fungi for 6 to 17 years. Vapam(r) decomposes to produce volatile fungicides as well...
A small block test was used in assessing whether pelletized sodium n-methyldithiocarbamate (NaMDC) would decompose and produce methylisothiocyanate (MITC) and thereby eliminate Antrodia carbonica colonies from Douglas-fir heartwood. Also evaluated were the effects of wood moisture content, dosage, incubation period, pH level, and presence of copper sulfate on percentage of...
Metal-plate-connected wood trusses with semi-rigid joints were investigated by the matrix method of structural analysis. The element-stiffness matrix and fixed-end forces of an individual member with one or both ends semi-rigid were derived as modifications of the idealized cases. The case of unequal elastic connections at two ends of a...
The effects of moisture content, flow direction, concentration, and temperature on the diffusion of chloropicrin in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) heartwood were investigated. Diffusion coefficients were strongly affected by wood moisture content. Coefficients for radial and tangential diffusion at the fiber-saturation point were twice as high as those at...
Studies of the effects of various chemicals on fungal growth are difficult to perform on filamentous fungi because of the difficulty of observing the protoplasm through the rigid hyphal wall, and because most activity occurs in the region near the hyphal tip. However, hyphae can be exposed to certain enzymes...