Distortions in coordination polyhedra may be effected by (1) displacement of the central atom from a reference position within the polyhedron (bond-length distortion) and (2) displacement of the ligands from the apices of some reference polyhedron (edge-length distortion). For tetrahedral coordination the bond-length distortion parameter (BLDP) and edge-length distortion parameter (ELDP), which are linearly related to these two types of distortions, have been defined and compared with other distortion parameters currently in use. Among tetrahedral oxyanions of non-transition elements, ELDP values of those exhibiting small bond-length distortions (e.g., LiO₄⁷⁻ and Ga₄⁵⁻) increase with the number of shared edges. For the oxyanions that show small edge-length distortions (e.g., Po₄³⁻ and SO₄²⁻) BLDP is related to the degree of tetrahedral polymerization. Although the relationships for oxyanions exhibiting fairly large ranges in both BLDP and ELDP (e.g., SiO₄⁴⁻) are not as straightforward, the same trends are recognized. For tetrahedral oxyanions of transition metals these structural trends are not well-developed. For tetrahedral oxyanions of all but one non-transition element considered, bond angle variations are entirely or largely a function of O•••O variations; for SO₄²⁻, O-T-O variations are mainly a function of T-O bond length variations. With regard to transition metal oxyanions, those of V⁵⁺, Cr⁶⁺, and Mo⁶⁺ tend to have bond angles near 109.47°, while those of Fe³⁺ and Zn²⁺ behave much like oxyanions of non-transition elements. Baur's (1970) Rule 5 does not represent a generally adequate model for tetrahedral oxyanions. Revised values for five of Shannon and Prewitt's (1971) effective tetrahedral ionic radii are presented, along with new values for the effective tetrahedral ionic radii of Ti⁴⁺ and Cu²⁺. For tetrahedral oxyanions of non-transition elements the maximum value of bond-length distortion appears to be limited by a phenomenon analogous to the "rattling" of the hard-sphere model. The maximum edge-length distortions appear to be limited by coulombic repulsions between bonding electron concentrations, with non-bonded interactions becoming important at very small O•••O separations. For transition metal oxyanions it appears that the same factors may limit the maximum edge-length distortions. There is evidence for greater polarization of either the oxygen atoms or cations (or both) in the oxyanions of transition metals than in those of non-transition elements. The crystal structure of slawsonite (SrA1₂Si₂O₈) has been refined to R = 0.048. Cell dimensions are positively correlated with both and <M-O> and <<T-O>>. Slawsonite appears to be fully ordered with <Si-O> = l.624Å and <Al-O> = l.748Å. Even where ordering is complete, <Si-O> apparently varies with structure type and cation combination. The crystal structure of a celsian (Cn_~₉₅Or_~₅ ) has been refined to R = 0.034. Results are very similar to those of Newnham and Megaw (1960). In both celsians, bond lengths suggest that there is ~17 percent disorder in excess of that required by the deviation of the Al:Si ratio from 1:1. Considering similar synthetic materials which show partial disorder, it is concluded that the Al-avoidance principle is not operative for compounds with the celsian structure. / Ph. D.

Nuisance populations of egeria (Egeria densa Planchon) hampered the use of the 1093 ha Chickahominy Reservoir, Virginia, as a source of recreation and potable water. A mixture of diquat dibromide (6,7-dihydrodipyrido (l,2-a:2,l'c)pyrazinediium dibromide) and potassium endothall (7- oxa.bicylq;>, z,1 )heptane-2 ,J-dicarboxylic acid) was applied at 2.83 liters of each chemical per 0.4 surface ha. There were no measurable changes in water quality after treatment and macrophyte die-off with the exception of a general decrease in dissolved oxygen; no fish kills were observed. Both herbicides declined to very low levels in the water 3 days after treatment and were undetectable within 16 days after treatment. Concentrations of diquat in.egeria were twice as high and persisted two times longer than concentrations of endothall. No endothall was found in bottom sediments. Diquat persisted in hydrosoils for one year. No herbicides were found in fish muscle tissue. Diquat and the mixture were equally effective at all concentrations tested in laboratory experiments at controlling five species of aquatic plants. Toxicity of endothall was much less than the toxicity of diquat and the mixture. Quantitative plant sampling augmented by aerial infrared photography revealed that egeria had repopulated the shallow areas of the reservoir one year after treatment but only repopulated the deeper areas by 42% by two years after treatment. LYngbya sp. increased in quantity especially in the deeper areas following treatment. Floating artificial substrates were employed to monitor in situ effects of treatment on macroinvertebrates. No toxic effects due to treatment were noted. Weed removal also did not affect growth of bluegill sunfish (Lepomis macrochirus). Tissues of bluegills collected after treatment did not histologically appear to be affected by the herbicides. The Lc50 values for diquat and endothall separately and combined were determined for four species of fish. The toxicity of the mixture was set by the toxicity of diquat. Concentrations approximating those applied in the field (0.11 mg/liter diquat with 0.17 mg/liter endothall) did not alter bluegill respiration rate. Concentrations of the mixture as high as 11.0 mg/liter diquat and 17.0 mg/liter endothall tested over 96 h in bioassays did not cause histopathological changes in bluegill gill, kidney, or liver tissue or cause changes in hematocrit, total plasma proteins, plasma protein electrophorograms or white blood cell differentials. Goldfish exposed to diquat and endothall separately (maximum 11.0 mg/liter diquat and 17.0 mg/liter endothall) and combined (maximum 11.0 mg/liter diquat with 17.0 mg/liter endothall) had no alterations in plasma glucose, glucocorticoids, androgens, estrogens, hernatocrit, or white blood cell differential. No histopathological changes due to treatment were found in goldfish interrenal, thyroid, hernatopoietic or sensory tissues; gill lesions occured at maximum concentrations. The mixture field concentration did not cause avoidance in goldfish. Higher concentrations of diquat (1.1 mg/liter) and the mixture (1.1 mg/liter diquat with 1.7 mg/liter endothall) were avoided. Endothall was not avoided until concentrations were increased to 17.0 mg/liter. Anglers agreed with the use of herbicides to control aquatic weeds, and were willing to refrain from fishing while the treatment was carried out. Anglers believed that the Chickahominy weed control project increased fishing and boating enjoyment. / Ph. D.

Chemical parameters of Lake Bonney, southern Victoria Land, Antarctica, were closely monitored during the 1973-74 and 1974-75 austral summers using marine analytical techniques and the method of standard additions. Results were at variance with reports of several previous investigators. Inorganic nitrogen was found to be present in high concentrations, particularly in the monimolimnion, and the dominant inorganic species was generally ammonia. Orthophosphate-phosphorus concentrations in the mixolimnion were ordinarily less than 10 µg/l throughout the study. Water samples were analyzed for the presence of copper, cobalt, iron, manganese, molybdenum, and nickel using flameless atomic absorption. More than 90 percent of the mass of each trace metal was found to be in the monimolimnion. Manganese was by far the most abundant trace metal in the lake, and some evidence suggests it may present a toxicity problem to algae in the surface waters. Concentrations of copper potentially toxic to at least algal species in the lake were present in the monimolimnion and, at times, in the mixolimnion. Continuous monitoring of one meltstream showed flows to be highly variable. Most of the orthophosphate-phosphorus carried to the lake by this meltstream was transported during the first two weeks of flow, probably due to the leaching of phosphates from the products of weathering generated over the long Antarctic winter. Whereas the meltstreams were previously considered as potential sources of significant quantities of nitrogen and phosphorus, it was determined that they probably contribute relatively minor amounts of these nutrients. The loading of trace metals to the lake also appears to be of minor importance, with the possible exception of cobalt. A decided peak in sulfate concentration and concomitant drop in pH was observed during each field season. Because no precursor to the sulfate could be identified, the mechanism for this phenomenon is not apparent, but may be related to subterranean inflow. The hypothesis that there is intermittent subterranean inflow at depth in Lake Bonney was supported by fluctuations in various chemical parameters. / Ph. D.

A broad-based investigation seeking to characterize fatigue damage mechanisms in fiber reinforced composite materials, accounting for the effect of cyclic loading frequency, is presented. A many faceted approach to the investigation was utilized; which included well documented strain-controlled fatigue tests, a scanning electron microscopy study, implementation of energy emission techniques (such as acoustic and thermal emissions), and the development of an energy-based failure theory. A detailed discussion of each aspect of the investigation is presented and, in each case, pertinent conclusions are drawn. The effect of cyclic loading frequency on fatigue damage development is documented and found to be substantial. A micro-mechanical damage model, which accounts for the effects of frequency and fiber/matrix interface strength, is developed. Using a first law analysis, a good correlation between acoustic and thermal emission with damage propagation and extent is developed. Finally, a new conceptual theory, called the Strain Energy Release-Potential Theory, is postulated. Predictions based on this theory are made and compared with experimental findings, resulting in substantial agreement. / Ph. D.

In recent years Citizen Interest Groups (CIGs) have become an important factor in the implementation of environmental regulations and hence in the allocation of scarce resources via the political process. This study examines the impact of environmental CIGs on the implementation of the Clean Air Act. It does so by focusing on how changes in various institutions have affected the efficacy of the principal CIG tools of litigation, lobbying, and media usage. The impact on CIG behavior of tax subvention, the judicial interpretation of standing and fee-shifting, and EPA implementation of provisions for citizen participation in the Clean Air Act is assessed. Los Angeles is employed as a case study in order to focus on the impact of the above-mentioned institutions on the implementation process. Positive criteria for the subvention of private externality producing activities are developed in the final chapter. / Ph. D.

The expectations of three groups--school superintendents, school psychologists, and school psychologist trainers--for the Virginia school psychologist's job performances, professional participations, and personal attributes were surveyed by means of a mailed opinionnaire. The degree of intrapositional and interpositional consensus was determined, as was the perceived importance of the school psychologist's generalized functions and the relative frequency of performance of each function. Certain demographic data were collected, and the effect of demographic variables on the expectations of role definers was investigated. The majority of the respondents held positive expectations for about two-thirds of the job performances of the school psychologist suggested by items of the opinionnaire. Most role definers held neutral to moderately positive expectations for the professional activities of the school psychologist, but held no strong preference regarding such personal attributes of the psychologist as age, sex, marital and parental status. The majority of respondents preferred that the school psychologist have training at least to the master's level, have training in education and psychology, and have completed a nine month internship. Higher levels of consensus within and between groups were found on expectations for the professional participations and personal attributes, than for the job performances of the school psychologist. The greatest agreement between role definers existed on items concerning the more traditional functions of the school psychologist, where positive expectations were almost universally expressed. The highest level of intrapositional consensus was found among school psychologist trainers; the lowest level among school psychologists themselves. The highest level of interpositional consensus existed between superintendents and trainers; the lowest level between superintendents and psychologists. Discordance between role definers resulted not so much from differences in opinion, as from differences in the intensity with which opinions were held. Although there was moderate disagreement between role definers regarding the relative importance of the school psychologist's functions generalized into ten major service areas, respondents appeared to agree as to whether the service area was most important, important, or least important. Most participants ranked diagnostic studies as the single most important functional area of the school psychologist. (School psychologist trainers, however, believed consultation with teachers a more important service area.) Findings support the assumption that school psychologists in Virginia are actually performing most frequently those functions the three role definer groups considered most important, and least frequently those functions that were considered least important. The effect of demographic variables on importance and frequency rankings was not found to be great. It was concluded that greater consensus regarding the role of the Virginia school psychologist exists today than in the past. Potential implications of the results of this study were discussed, and recommendations for further research offered. / Ed. D.

A solution is presented for the stress distribution around holes in laminated composite plates under pure bending. The shear deformation, lamination theory is derived and employed for the analysis of circular, elliptical, square, and diamond-shaped holes piercing the laminated composite plate. Each layer of the laminate is assumed to be homogeneous and to have isotropic properties. Functional analysis employing complex variable methods is used to solve the governing equations. Using conformal mapping and boundary form perturbation techniques, the circular hole solution has been extended to the solution of the curvilinear hole case. These analytical solutions are compared with the solution obtained from a 72 DOF finite element method. The stress resultants and stress couples around the hole, the interlaminar stresses, as well as the tangential stress through the plate thickness are studied. In addition, the boundary layer phenomenon in the vicinity of the hole is presented. / Ph. D.

The “Limits to Growth” controversy has identified attainment of a steady-state world system as an essential goal for human culture. This study investigates implications of steady-state systems using principles of thermodynamics in conjunction with Systems Dynamics simulation techniques. Evaluation of Forrester’s World Dynamics model shows it to degenerate in accordance with the dictates of the Second Law of Thormodync.mics. Two fundamental policy criteria are established for world society: 1. Maximization of the future horizon for mankind. 2. Satisfaction of basic quality-of-life requirements for all of mankind. Optimization principles for satisfaction of these criteria are derived from interrelationships found to exist between three physical laws (Einstein’s relativistic mass-energy and the First and Second Laws of Thermodynamics), non-equilibrium thermodynamics (Prlgogine’s Theorem of Minimum Entropy Production as the defining condition for a steady-state system) and a cultural law (the Golden Rule). Policy based on the Principles of Minimization of Entropy and Cooperative Behavior are presented as the optimal means for defining, achieving and maintaining long-term steady-state systems both locally and globally. It is shown that the “Golden Rule” shares with the thermodynamic concept of equilibrium the defining mechanism of “reversibility” (synonyms: reciprocity, self-returning, “frictionless”, ideal efficiency, etc.). This common criterion allows both concepts to be used as unambiguous, perfect standards for determining the relative effectiveness of actual performance (one in terms of cultural behavior and the other in terms of physical behavior). Recognition of this relationship (which reflects the fundamental tendency of natural systems to seek optimal stability conditions in the most efficient manner) is advanced as a means for achieving optimal steady-state solutions for complex cultural- physical systems; specifically: 1. Use the Principle of Minimization of Entropy (with respect to the equilibrium standard) when making decisions that essentially involve physical behavior. 2. Use the Principle of Cooperative Behavior (with respect to the Golden Rule standard) when making decisions that essentially involve cultural behavior. The effects of these policies are identical: the minimization of system “friction”; or, conversely, the maximation of system “welfare”. These principles are embedded as policy tables in Forrester’s World Dynamics model and used to demonstrate the conceptual feasibility of achieving truly long-term steady-state solutions satisfying desirable quality-of-life goals. In order to demonstrate the practical potential of such policies, the Principle of Minimization of Entropy is related to the engineering concept of Thermodynamic Analysis and advanced a method for evaluating Total Energy Systems. Two application schemes are presented as examples which represent the range of both Total Energy System technology and analytical procedure: 1. A manually calculated Decision Tree Analysis for a Wind Source Total Energy System emphasizing simple technology that can be immediately utilized world-wide (using indigenous “self-help” labor and materials) to satisfy small scale “biotechnic" community needs. 2. A DYNAMO simulation model for a Laser-Fusion Total Energy System offering the ultimate range in resource management technology needed to support complex, large-scale communities. The study is closed with a suggested subject for further research: development of an “Evolutionary Dynamics” model based on Prigogine’s thermodynamic concepts for “open” systems. / Ph. D.

A methodology was developed by which a state fish and game agency can determine Optimal Ecosystem Policies (OEP). This methodology consisted of: (1) an ecosystem simulation model which depicted a variety of interactions among and between species; (2) an objective function consisting of several criteria; and (3) a computer implemented optimization procedure designed to find the time sequence of decision activities which maximized the objective function. OEP was applied to a specific case study area, a stream fishery in Rich Creek, Monroe County, West Virginia. The simulation model consisted of a system of difference equations calculated for discrete time stages (one year time horizon). Interaction was modeled using a special queueing framework, where an animal's actions were governed by a preemptive priority sequence. Using the queueing framework, all interactions become density-dependent, and probability parameters may be estimated subjectively. Ration size, mortality, and reproduction were calculated and were inputs to population abundance, growth, and metabolism calculating routines. The criteria considered in the objective function in the Rich Creek study were: (1) catch per unit effort by the commercial operators summed over all time stages (a measure of benefits to the commercial fishermen); (2) the environmental stability measured by a diversity index; (3) the number of fishermen visiting the stream during the year (angler-days); and (4) the sum over the year of a measure of angler satisfaction (utility). The utility function was a function of the attributes: size of fish caught, species of fish caught, number of fish caught, and crowding by other anglers. The utility model was empirically determined and it was found to be multiplicative over the attributes. Terminal (year end) constraints in OEP were a budgetary constraint, a diversity constraint, and a commercial catch constraint. Thus, the objective was maximization of a linear combination of the four criteria subject to the three terminal constraints. The approximate optimal solution was found by search by Regression and Application of the Maximum Principle (RAMP search). Quadratic transition functions were fit to simulated data and the optimal policy was found for these transitions using the discrete maximum principle. This policy was returned to the simulation to generate new data and the procedure was iterated until a convergence criterion was met. Optimization and sensitivity analysis of the Rich Creek model showed that an adequate budget was needed to maintain levels of stocked trout (the preferred species) to produce relatively high levels of angler utility. At low budgets other species became more important and diversity became an active constraint. Diversity and commercial catch criteria conflicted, therefore optimal catch occurred early in the year so that diversity could recover later. Solutions were most sensitive to three system components: (1) human aspects such as population size, preferences, and angler abundance; (2) the temperature prediction function (it served as a driver for many other variables); and (3) trout biomass variables.Future research on Rich Creek should be directed toward these three components. / Doctor of Philosophy

The study concerned Dr. Woodrow W. Wilkerson who served as State Superintendent of Public Instruction for the Commonwealth of Virginia from August 16, 1960, to April 1, 1975. His length of service exceeded that of any of the thirteen previous superintendents in the 103-year history of public education in Virginia. The thesis of the study was that the Commonwealth of Virginia made strides toward improvement in the quality of education during the leadership of Dr. Wilkerson. A detailed biographical study of Dr. Wilkerson pointed out his unique personality influenced by all with whom he came in contact; his family, his church, his college professors, his educational associates, and others. The position of State Superintendent of Public Instruction was discussed with Dr. Wilkerson and six of his associates. The relationship of his position with the State Board of Education, the members of the General Assembly, the various governors, and the local division superintendents was presented. This composite description of the past fifteen years in public education in Virginia indicates how the position actually operated. The legal basis of the position of State Superintendent of Public Instruction was described. A procedure was established to identify and analyze changes which occurred in public education during Dr. Wilkerson's tenure. General measures of educational quality for the nation were identified. Specific educational goals in Virginia from various sources were established. These goals were classified and given priorities by a panel of experienced educators. A questionnaire was sent to eighteen carefully selected representatives of the Virginia educational community who ranked the goals according to their significance. Ten highest ranked goals were associated with measures of educational quality. A panel selected ten goals for which comparative educational data might be available. A collection of data for the years 1960 through 1974 in Virginia and the nation was made. In many cases comparable data were not available. A determination of the degree of success on the ten measures of quality was made. The questionnaire also indicated that the major educational goal in Virginia during Dr. Wilkerson's tenure was the standards of quality program. Dr. Wilkerson and close associates were interviewed concerning the development and implementation of the important program. Aspects of the program with which Dr. Wilkerson was involved were discussed in detail. An evaluation of the program and its effectiveness was presented. Dr. Wilkerson's accomplishments were influenced by the many issues of his time, by the personalities that he encountered, and by the limitations placed upon him by various political and economic conditions. Dr. Wilkerson and his unique personality had a marked effect upon public education in Virginia. The Commonwealth of Virginia made progress in the improvement in the quality of education during the leadership of Dr. Woodrow W. Wilkerson as State Superintendent of Public Instruction. / Doctor of Education