The oxidative addition of E-H bonds to [Ir(1,5-COD)(PMe₃)₃]Cl (1,5-COD = 1,5- cyclooctadiene) has been previously studied (E = B, C, N, O, S). Some of the resulting species have shown activity as catalysts for hydrogenation and the addition of other molecules to unsaturated species. More recently, the addition of amino acids to [Ir(1,5- COD)(PMe₃)₃]Cl was studied in an attempt to create molecules with biological activity as well as species which might be active in asymmetric catalysis. Although inactive as catalysts, one of the these amino acid complexes was shown to be an anti-HIV agent. This finding prompted research into the additions of other molecules of biological importance to [Ir(1,5-COD)(PMe₃)₃]Cl. Since phosphates are an important functional group in biochemistry, the purpose of this research was to study the possible binding modes of the phosphate group to the iridium center and then to react biologically occurring phosphates with [Ir(1,5-COD)(PMe₃)₃]Cl. The reaction of dibenzyl phosphate (DBP) with [Ir(1,5-COD)(PMe₃)₃]Cl has been studied in detail. The resulting complex, Ir(PMe₃)₃(H)(DBP)Cl, is soluble in most common laboratory solvents with the exception of ether and was characterized by infrared, ¹H, ³¹P, and ¹³C NMR spectroscopy and elemental analysis. The dibenzyl phosphate ligand is labile and is easily displaced by nucleophiles. The complex does not undergo reaction with molecular hydrogen at ambient temperatures. Dialkyl phosphate complexes were easily made using the same synthesis as the dibenzyl phosphate. This reaction was unsuccessful for the preparation monoalkyl and diaryl phosphate complexes. The reaction of [Ir(1,5-COD)(PMe₃)₃]Cl with the nucleotides 2'-deoxyadenosine- 5'-monophosphate (d-AMP) and (-)-adenosine-3'-5'-cyclic monophosphate (cyclic-AMP) did not result in the formation of a single product perhaps because the phosphate groups in these compounds are diacids. The reaction of [Ir(1,5-COD)(PMe₃)₃]Cl with 1,2- dihexadecanoyl-rac-glycero-3-phosphoethanolamine (PEA), a dialkyl phosphate, produced only the N-H addition product. / Master of Science

The mitochondrial utilization of a-ketoglutaric and pyruvic acids have been found to be depressed in guinea pig and bovine ketosis. Addition of sodium acetoacetate to the reaction medium resulted in depressed oxidation of pyruvate and 1-ketoglutarate of isolated normal rat liver mitochondria. / Ph. D.

Federal law requires hearing protection device (HPD) manufacturers to provide attenuation ratings for use in estimating workers’ protection levels. These ratings, which are laboratory obtained, typically overestimate the actual protection levels achieved in the workplace. This research investigated laboratory protocols for yielding improved estimates of HPD in-field performance. Two experiments were conducted. The first was a pilot study developed by an American National Standards Institute (ANSI) working group. In this experiment, two types of earplugs were tested, a user-molded, malleable foam plug and a pre-molded, multi-sized rubber plug. Attenuation data (obtained using a psychoacoustical real-ear-attenuation-at-threshold measurement procedure) were collected across 10 subjects who entered the study as novice HPD users but were considered experienced HPD users in the latter half of the study. Four testing protocols involving two levels of HPDs, two levels of instruction-insertion techniques, and two levels of user experience were investigated. The same 10 subjects participated in all treatment conditions of the experiment. The second experiment involved similar protocols as the first; however, only one plug type was tested (the pre-molded, multi-sized rubber plug). Four testing protocols involving two levels of instruction-insertion techniques, two levels of user experience, and two levels of auditory feedback [fitting noise] were investigated. Forty subjects participated; each subject was tested in two treatment conditions. The attenuation results of each experiment were analyzed by statistical techniques. Statistical comparisons of results were made between the two experiments as well as between the experiments and selected field data. The major finding of the research was that fitting noise did not help subjects achieve higher attenuation [better protection] when consciously used for that purpose. Other findings indicated that novice subjects using only HPD manufacturer's instructions achieved attenuation that more closely represented the field attenuation than subjects tested under other conditions. However, the results were plug specific, in that no laboratory protocols yielded attenuation similar to the field data for the foam plug. / Master of Science

The main objective of the VPI-CE control network. is to contribute to the Nation.al Geodetic Survey control network. In order to meet this objective, large amounts of survey data were accumulated at different times from various surveys between the years 1977-1980. Bach different set of survey data was reduced and adjusted by least squares independently creating various "sub" control networks that were connected to each other peace- . meal. When "sub" control networks were connected to each other, it was found that they did not meet the objective stated above. It is the purpose of this project to examine and check all survey data, adjust all data as one set to the NGS control network, and to evaluate the adjusted data to see if the survey meets second-order class II traverse specifications as established by the NGS. Included in this paper are the following: a background on NGS specifications; least squares theory including observation equations, and error theory; a description of how data for the project was accumulated and reduced; the adjustment of the reduced survey data; results and analysis of the adjustment; and conclusions and recommendations for the survey. / Master of Engineering

This thesis began by studying how a temporary event could create permanent architecture and how that architecture could change an urban lifestyle. I chose the Olympics as the event and proposed that they be held in Washington D.C., a city of international prominence with a rich design history but a city that hasn't had a large scale urban redevelopment plan in over a century. I focused on the city east of the Capitol as I wanted to extend the monumental core created in the McMillan plan. I researched baroque design, Olympic planning, and even the original L'Enfant plan. The result of this research was unearthing some of the original L'Enfant design elements and incorporating them into a 21st century city by blending new design issues with the idea of a city designed around radial vistas with magnificent termini. I focused on two sites, the Olympic Torch and the Olympic Stadium. The Torch is situated as a terminus on a site that was intended to be mile marker zero for the country. Its design and importance make it a monument while still not impeding the views. The stadium was created to serve as a stadium for the people, allowing pedestrians outside to view and interact with the event inside. It is sunken so as not to obstruct views but it is spanned by arches that pierce the cityscape signifying its monumentality and appropriately ending the monumental axis started with the Lincoln Memorial on the western edge of the city. / Master of Architecture

Research has demonstrated that the majority of antihistamines (H1 antagonists) have sedative effects and can impair psychomotor performance; however, it is claimed that astemizole (hismanal) does not possess central nervous system side effects. A two-factor, repeated measures, double-blind design was used to compare the effects of three treatments (two antihistamines and one placebo) on cognitive information processing, mood, selected physiological measures, subjective feelings of drowsiness, and subjective performance ratings in 28 healthy men. Evaluations were given at 1,3,5,7,9,11,13, and 15 hours post ingestion. Time-of-day effects were evident in following directions, unstable tracking, code substitution, serial addition/subtraction, logical reasoning, manikin, and pattern comparison tasks. A general trend of improved scores through the day was observed and a temporal pattern of a low performance was suggested in the afternoon (2:00 pm and 4:00 pm). Temporal effects were noted for physiological measures. Benadryl produced performance decrements at one hour post ingestion on the following directions task, at one and a half hours on the unstable tracking task, and at three hours on the serial addition/subtraction task. No decrements in performance were found post ingestion of hismanal and, in fact, the hismanal group performed the serial addition/subtraction task more quickly than either the placebo or benadryl groups at five hours post ingestion. At three and a half hours post ingestion, the performance of the benadryl group remained poorer than the hismanal group on unstable tracking, but was not different from the placebo group. A higher level of tension, greater fatigue, and lower level of activity was experienced post benadryl. Lower vigor-activity and higher confusion-bewilderment post hismanal and benadryl were noted one hour post ingestion; however, confusion was lower and activity was higher for hismanal than benadryl. Low vigor-activity, high confusion, increased sleepiness, and low perceived performance post benadryl persisted for three hours, while fatigue-inertia persisted for seven hours. Subjects were able to determine receipt of a placebo versus an antihistamine following ingestion of either a placebo or benadryl. Results suggest that hismanal is superior to benadryl for avoidance of subjective effects and performance of information processing tasks. / Ph. D.

Rating scale techniques have been recommended for mental workload assessment. The Modified Cooper-Harper (MCH) Scale is a decision tree scale which has proven to be a reliable indicator of workload. Five additional rating scales were developed to examine rating scale features including a) number of rating scale alternatives, b) decision tree format, c) decision tree hierarchy, and d) (two) computer-implementation(s). The purpose of this study was to improve the sensitivity of the MCH Scale and to try to identify what aspects of the scale contribute to its effectiveness. A simulated flight task emphasizing mediational (cognitive) behavior was used to present low, medium, and high levels of loading to 6 student and thirty licensed pilots. In a Singer-Link GAT-1B flight simulator, the pilots performed three counterbalanced load level flights. After each simulated flight, a rating scale and questionnaire was administered. The results indicated that the paper rating scale having 15 response alternatives and the original decision tree was the most sensitive to load. Both 10-point modifications, the computerized version of the MCH Scale and the version with the decision tree format removed, were somewhat superior to the original MCH Scale, which was also sensitive to load. These findings, however, are not consistent with those obtained in a companion study of communications tasks, indicating that these rating scale measures are task dependent. Use of the MCH Scale is recommended since it alone has consistently demonstrated sensitivity to load across tasks and across studies. / M.S.

Perspective and Purpose Recent investigations by Steffe, Richards, and von Glasersfeld (1979) have indicated that addition and subtraction problem-solving competencies are developmental in nature and that these competencies build upon counting abilities. They postulate that, in beginning addition and subtraction, a type of problem-solving strategy termed counting-all develops prior to another kind of strategy termed counting-on (for addition) and counting-back (for subtraction). If these tasks are developmental, one may assume that students approach the tasks in qualitatively different ways based upon their developmental levels. Neo-Piagetian researchers have postulated that a quantitative measure of development explains the qualitatively different ways in which children react to the same cognitive task at different stages of development. The measure, termed mental space or M-Space, describes the number of schemes which may be coordinated at one time. First graders, the majority of whom have an M-Space of a+2 or a+3, are capable of solving addition and subtraction word problems by utilizing the counting-all and/or the counting-on (back) strategies. Given this information, the purpose of this study was to determine what effect M-Space level has on the strategy a subject uses to solve problems when he is trained on a strategy which either matches or mismatches his M-Space level. Design To determine whether a match between M-Space and strategy demand is necessary or whether instruction will facilitate the chunking of schemes which allows the developmental task to be solved by a strategy which would otherwise be above the subject's M-Space level, the following steps occurred: one hundred thirty-nine first graders were pretested to identify those who could count to sixteen, perform numeral/number correspondence to sixteen, but could not solve addition and subtraction number fact problems to sixteen. One hundred fifteen subjects meeting these criteria were given the Cucumber Test and Backward Digit Span Test to assess their M-Space levels. After eliminating subjects before and during training, 50 subjects remained. Twenty-six subjects with an a+2 M-Space were divided into two training groups. Approximately half of the group was trained to use an a+2 strategy (the count-all strategy) to solve addition and subtraction word problems and the other half of the group was trained to use an a+3 strategy (the count-on (back) strategy). The same training procedure was used for the twenty-four subjects with an M-Space of a+3. Four to five weeks later, a delayed posttest consisting of four addition and four subtraction problems and one each of three types of transfer problems was presented. Results Mann-Whitney test results indicated that there were significantly fewer a+3 responses by the subjects with an a+2 M-Space who were trained to use an a+3 strategy than there were for subjects with an a+3 M-Space trained to use an a+3 strategy. However, there was no significant difference between those with an a+2 M-Space trained on an a+2 strategy and those with an a+2 M-Space trained on an a+3 strategy. Results of other research questions indicated that subjects gave similar responses to transfer problems which varied by material or additional variable; for subjects with an a+3 M-Space trained on an a+3 strategy, there were significantly more a+3 addition responses than subtraction responses; the implied comparison subtraction problem was answered incorrectly more often than straight take-away subtraction problems, and students tended to devise simple addition and subtraction problems and solve them by using memorized number facts. Discussion The findings indicate that more study is warranted for the application of the M-Space construct to a theory of how mathematical knowledge develops sequentially, the different ways in which addition and subtraction tasks can be conceptualized, and the instructional implications of applying a developmentally based theory of instruction to mathematics problem-solving. / Ph. D.

Numerous Investigators have reported that NH₄⁺ uptake reduces the yield and quality of flue-cured tobacco (Nicotiana tabacum L.). Metalaxyl, a fungicide commonly used in the production of flue-cured tobacco, has been patented as a nitrification inhibitor. The objectives of this study were to 1) determine the influence of metalaxyl at commonly applied rates on the + nitrification of NH₄⁺ from various sources; 2) study the Influence of soil pH on inhibition of nitrification by metalaxyl; 3) study the Influence of N source and metalaxyl on N accumulation in the plant; and 4) evaluate the influence of N source and metalaxyl on the yield, quality, and chemical composition of flue-cured tobacco leaf. Field, greenhouse, and laboratory experiments were conducted in the Southern Piedmont region of Virginia in 1984 and 1985 to carry out these objectives. Metalaxyl was found to reduce the population of NH₄⁺ oxidizers in soil and inhibit nitrification at applications of 0.56, 1.12, and 3.36 kg ha⁻¹. The inhibitory effects of metalaxyl were much weaker than nitrapyrin. Nitrification was inhibited by metalaxyl only in soils where nitrification was slowed by low pH and wet conditions. In soils of high nitrifying capacity, metalaxyl did not inhibit nitrification. Nitrogen uptake was enhanced by high NO₃⁻ concentrations in the soil, except where metalaxyl reduced NO₃⁻ leaching. Cured leaf concentrations of N were not affected by N source but were slightly reduced by metalaxyl. Nitrogen source and metalaxyl did not affect yield, total alkaloids, or reducing sugars. Quality Index was reduced by decreased soil NO₃⁻ from both N source and metalaxyl. / M.S.

The design and analysis of finite length, multiple layered, induced strain actuators is investigated. A model of an arbitrary multiple layered actuator is utilized to predict the applied force and moment from the i^th layer onto a structure. The transverse equations of motion of a simply supported beam are derived using Timoshenko beam theory. This approach accounts for shear deformation and allows the actuator-applied moments to be directly incorporated into the equations of motion without further approximation. The model is cast in state space form and an assumed mode method is used to solve for the forced response of a nonuniform beam. Experiments are performed verifying the developed analytical model. The first experiment characterizes the dynamic properties of five different actuator/substructure configurations. Results indicate the system natural frequencies decreased and the structural damping increased with more attached actuators. Analytical predictions are shown to be in good agreement with the experimental results. / Master of Science