Although the drying process can improve the overall quality and usefulness of forest products, if drying is not carefully controlled, drying loss can be substantial. As most drying defects occur when the lumber moisture content is above fiber saturation point (FSP), measurement of moisture content (MC) above FSP is critically important. In this study, a technique was developed which permits use of an electrical resistance moisture meter RDX-1 (Delmhorst Instrument Company) to measure MCs of red oak and yellow-poplar during drying when MC is above FSP. The Lignomat in-kiln probe electrode was used throughout experiments. Two experiments were conducted. The first dealt with developing a two-point technique to measure MC above FSP. The other evaluated the effect of the moisture gradient on the MC reading from the meter. During the drying, pin electrode also was used when oven-dry MC was about 40% in order to compare the MC readings by the pin electrode and the probe electrode. The experimental results show the correlation between the MC readings and oven-dry MC of the sample is quite high during drying; the correlation of each sample is higher than 0.9. Based on this relationship, two-point technique of measuring MC above FSP was developed. This technique can predict MC above FSP of red oak within 5%, and the MC of yellow-poplar within 10%. From the experiment, it was found, when MC is above FSP, MC readings measured by probe electrodes are significantly different from those measured by pin electrodes. It was also found that the moisture gradient affects the MC readings dramatically. The depths of probes inserted into the boards are an important parameter for measuring MC. Different depths yield different MC readings. / Master of Science

Inflation has been a recurrent and critical problem in many Latin American countries. Inflation is often combined with, among other problems, serious distortions in the structure of relative prices thus reducing efficiency of the pricing mechanism in allocating resources. The purpose of this study is to examine the effects of inflation and other variables on relative price variability in Peru using two different types of models. After preliminary evaluation of the stationarity properties of the series, a relative price variability measure is constructed using monthly data on 32 components of the CPI over the period 1979:12-1988:07. For the first models, series of expected and unexpected inflation in Peru, real exchange rate movements, and U.S. relative price variability are constructed and the effects of these variables on observed relative price variability are determined. The results indicate that increasing levels and unpredictability of inflation cause increased dispersion of relative prices. A distinction between expected and unexpected relative price changes is made in the second model. This distinction is relevant because not all price movements are viewed by agents as surprises that confuse price signals. To account for this distinction, a measure of conditional relative price variability is estimated using Engle's (1982) autoregressive conditional heteroskedasticity approach. Similarly, the conditional variance of domestic inflation is estimated and used as a measure of price uncertainty. Effects of the time-dependent conditional variances of domestic inflation and real exchange rate on a weighted average of the relative price shocks normalized by their conditional variances are evaluated and found statistically significant. Finally, both methods of testing empirically the hypothesis that inflation uncertainty increases relative price variability provided consistent results. / Master of Science

Two perspective-view electric wheelchair simulators were developed to enable therapists to prescribe electric wheelchair control interfaces better. The simulators may also be used to train clients to use control interfaces. One simulator presented the user with the visual perspective of sitting in a wheelchair. The other gave the visual perspective of being behind the wheelchair. The simulators were developed on a micro-computer to reduce their cost and promote more wide spread use in the rehabilitation fields. This study was to validate the wheelchair simulators by comparing user performance with the simulators to user performance with an actual wheelchair. Four disabled subjects and four able-bodied subjects navigated the simulators and an actual wheelchair through a similar course consisting of a path the width of the wheelchair. Performance measures relating to safety, such as RMS deviation from the path, number of crossings of the path boundaries, and maximum deviation per trial were obtained for both the simulations and the actual wheelchair driving task. Analyses of variance of these performance measures indicate that mean user performance with the simulators tended to be similar to mean user performance with the actual wheelchair. Correlational analyses suggest that performance with the simulators is predictive of relative performance with wheelchair in straight sections of the course. / Master of Science

A comprehensive stability analysis of a distributed power system (DPS) is performed. The possible performance degradation and stability problems caused by the loading effect of cascaded converters are analyzed. The effect of impedance overlap on the system and individual subsystems is examined. By applying the loop gain analysis technique, a forbidden region for the polar plot of the ratio of impedances at the interface between cascaded subsystems is determined. A method of transforming the forbidden region into a load impedance specification for a given source impedance is developed. The method guarantees system stability and minimal performance degradation of the DPS, while allowing impedance overlap at the interface. / Master of Science

This research investigated emissions of formaldehyde, acetaldehyde, carbon monoxide, and hydrocarbons from a small utility engine fueled with mixtures of gasoline, ethanol, and methanol. Measurements made for each fuel mixture, with and without a catalyst, allowed a qualitative evaluation of the catalyst effect on the aforementioned pollutants. California Air Resources Board small utility engine regulations motivated this research. The engine was loaded by an electrical generator with output of approximately 1000 watts to simulate actual operating conditions. Operation occurred at steady state conditions with a fixed air/fuel ratio. Alcohol addition reduced emissions of carbon monoxide (CO) and total hydrocarbons (THC) from gasoline only levels. Adding a 50% volume of ethanol to the fuel, CO and THC emissions decreased 75% and 50% respectively. Adding 50% methanol reduced CO and THC 95% and 60% respectively. Qualitatively, no catalytic control of CO or THC was demonstrated with any of the fuels used. However, a lack of replicates prevented quantification of catalyst results. Both formaldehyde and acetaldehyde emissions increased with the addition of ethanol. Addition of 50% ethanol resulted in an increase of at least 600% in acetaldehyde emissions. Methanol addition increased formaldehyde emissions, but correlation of emissions with alcohol content was not possible. Acetaldehyde emissions appeared to decrease with increasing methanol content after an initial increase from the gasoline only values. No catalytic oxidation of formaldehyde was demonstrated, but acetaldehyde emissions may have been decreased by the catalyst when employing 50% ethanol fuel. / Master of Science

A plethora of information has been amassed in attempts to understand the basic principles governing living systems. Since the birth of the modern scientific method, many compelling theories have been devised as scientists attempt to understand the mysteries of life. The endo-symbiont theory for the biogenesis of mitochondria and chloroplasts is one such theory that has recently gained increased in acceptance with the maturity of molecular and biochemical techniques. These two organelles are unique in that they contain DNA which codes for some of the proteins involved in organellar function. Maternal inheritance of some traits such as cytoplasmic male sterility (cms) in plants can be linked to mitochondrial DNA. However, further understanding of mitochondrial gene expression, regulation and DNA rearrangements has been hindered by the lack of a transformation system for these organelles. A longterm goal in the field is to develop a transformation and expression system for soybean mitochondria. Despite recent transformations of yeast mitochondria, no successful transformations of higher plant mitochondria have been reported to date. Mitochondrial transformation occurs at low frequencies, and therefore requires a method of selection, i.e. a means by which to differentiate cells containing a transformed mitochondrion from the background of largely untransformed cells. The work presented in this paper is the foundation for the future development of a selectable marker for plant mitochondrial transformation. The antibiotic oligomycin is an inhibitor of the mitochondrial ATP synthase complex, and therefore has potential for the isolation of a marker gene. Two approaches, soybean tissue culture mutagenesis and site-directed mutagenesis of the soybean [Glycine max (L.) Merr.] atp9 gene, have been explored in the hopes of isolating an oligomycin-resistant marker. In yeast (Saccharomyces cerevisiae), atp9 mutants have been shown to contain nucleotide mutations resulting in single amino acid substitutions that confer resistance to oligomycin. Sites for mutagenesis of the soybean atp9 gene were chosen based on DNA sequence homology between the yeast and soybean genes. Before site-directed mutagenesis, atp9 cDNA clones were cloned and sequenced, revealing RNA editing sites. Among these cDNA clones, we have also sequenced atp9 from an oligomycin-resistant soybean suspension culture for possible mutations in the gene. Suspension cultures were mutagenized with EMS and selected by growth inhibition with oligomycin. Inhibition curves showed an increased tolerance for oligomycin for EMS-treated cultures compared to wild-type. For future testing of the mutagenized atp9 gene we have constructed a particle inflow gun to introduce the gene(s) of interest into the nucleus of soybean suspension culture cells. A mitochondrial target sequence from β-atp has been fused in frame to the atp9 gene to direct the mutagenized gene product, now the product of a nuclear gene, correctly into the mitochodrion. / Master of Science

During the seventeenth century, science, and especially astronomy, underwent significant changes in which the emphasis on instrumentation shifted from a more qualitative approach to precise quantitative measurement. These changes were further encouraged by the formation of scientific societies, such as the Royal Society in London and the Royal Academy of Sciences in Paris, where members worked together as a collective to validate knowledge. Because members could freely dissent within the community, a prescribed behavior for participants in disputes was proposed, although seldom followed. Furthermore, disputes were not influenced by intellectual issues alone -- social factors also guided and influenced the course of controversies. This study is an analysis of one scientific controversy in which the participants deviated from the prescribed code of behavior in scientific disputes, and, although the controversy was guided primarily by social factors, intellectual factors ultimately determined its outcome. In the Introduction, I discuss two sociological theses (Merton, Shapin and Schaffer) which are relevant to scientific controversies. In Chapter 1, I describe the changing nature of astronomy and instrumentation in the seventeenth century with special emphasis on micrometers and telescopic sights. In Chapter 2, I explore the nature of scientific controversy vis-à-vis the Royal Society, and two particular controversies which did not deviate from the expected rules of behavior. A descriptive account of the Hevelius-Hooke dispute follows in Chapter 3, and in Chapter 4, I provide concluding remarks on the dispute. Finally, in the Conclusion, I discuss the intellectual and social contexts of the Hevelius-Hooke dispute. / Master of Science

Muskmelon (<i>Cucumis melo</i> L.) embryos are surrounded by a single layer of endosperm and a two- to four-cell-layered perisperm. The embryonic axis must penetrate the perisperm envelope (perisperm + endosperm) for germination to occur. Radicle emergence could result from increased turgor, weakening of the perisperm tissue, or a combination of both. In a previous report, turgor of the embryonic axis did not increase prior to radicle emergence. This suggests that weakening of the perisperm envelope is a prerequisite for radicle emergence in muskmelon seeds. The changes in cell wall sugars of the perisperm tissue were studied during imbibition using gas chromatography and high performance thin layer chromatography. The major cell wall sugars identified in the micropylar perisperm tissue were glucose, galactose, xylose, and rhamnose. Endo-β-mannanase has been shown to be responsible for endosperm degradation in seeds of Solanaceae, Leguminosae, and Fabaceae. However, the lack of mannose in the cell walls of muskmelon perisperm tissue suggests that this enzyme is not involved in muskmelon seed germination. Structural changes of the micropylar perisperm envelope tissue were visualized during imbibition using electron microscopy. Scanning electron microscope images revealed changes in the perisperm envelope before radicle protrusion. The cell walls of the perisperm envelope tissue were degraded starting 5 h prior to radicle emergence. An Instron was used to measure the mechanical resistance of the perisperm envelope during imbibition. The force and total energy required to penetrate the perisperm tissue of imbibed muskmelon seeds decreased gradually during imbibition. This study confirmed that the perisperm envelope tissue offered mechanical resistance to the expanding embryonic axis. Degradation of the perisperm envelope tissue before radicle protrusion facilitated radicle emergence. / Master of Science

A reliable estimate of minable coal reserves is essential for long-term planning and for conservation of energy resources. In the majority of the world's coalfields, seams are found on multiple horizons, and coal recovery may be significantly reduced depending upon the magnitude of seam interaction. In order to evaluate the effects of interaction in terms of coal losses, a hazard technique has been developed. The first stage in this technique was to develop an efficient and accurate system to grid spatial geologic and structural information developed from randomly placed boreholes. The second stage was to utilize these gridded values to determine total available coal tonnage and chemical compositions of the seam. Depending on whether over or under mining effects are to be assessed, spatial geologic and structural conditions between the seams, are evaluated to determine if interaction is possible. Where interaction will occur, recoverable reserves are reduced accordingly. To demonstrate application of the hazard approach, potential interaction in a lower seam has been evaluated. To facilitate implementation of this reserve evaluation method under multi-seam conditions, a user-friendly computer design program, HAZARD, has been developed to calculate the recoverable coal reserves in an affected seam. / Master of Science

In 1972, Bergman reported cycloaromatization via 1,4- benzenoid diradicals of enediyne systems. Since 1985, five enediyne fungal products with anticancer antibiotic activity have been structurally elucidated, namely, neocarzinostatin chromophore, the calicheamicins, the esperamicins, the dynemicins, and kedarcidin chromophore. These compounds are delivered to DNA by a targeting mechanism and upon activation undergo a series of reactions which results in the generation of radicals via Bergman or Myers cyclization. Myers cyclization is aromatization of certain enynylallenes to Q,3-dehydro toluene diradicals. These radicals then abstract hydrogen atoms from DNA resulting in strand cleavage. The goal of my research project is the synthesis of enediynylacridans s~ch as 3,6-bisdimethylamino-9-[3-(2- ethynylphenyl)prop-2-ynyl]acridan which potentially have the same type of anticancer antibiotic activity as the natural products. Oxidation of the acridan (dihydro acridine) to the acridine would induce base catalyzed propargyl-allenyl isomerization. This would serve as the triggering device which leads to Myers cyclization and thus the diradical. The acridine portion of the molecule would also serve as the delivery system, as acridines are known to interact with DNA via intercalation. There is also interest in determining to what extent an N-oxide functionality would accelerate the Myers cyclization due to the incipient nitroxide radical. Another area of interest involves chemical oxidation of the acridans to the acridines. / Master of Science