A coordinated computational undertaken to investigate the and experimental study was behavior of the vortices trailing from low aspect ratio lifting surfaces. Vortex formation in the near-wake was measured in a wind tunnel with yaw-head and hot-wire probes at three different Reynolds numbers, the highest of which was greater than most previous studies. These near-wake measurements provided initial conditions for the far-field computation with the parabolized Navier-Stokes equations written in terms of vorticity and stream function. Turbulent transport was modeled through the turbulent kinetic energy and the Prandtl-Kolmogorov hypothesis to give an eddy viscosity. The experimental results showed that the effects of Reynolds number are significant for vortex formation in the nearwake, and the computation adequately effects. However, the decay trend in the far-field is essentially unaffected by the Reynolds number, and the predicted decay for maximum tangential velocity agreed very well with Iversen's correlation. / Ph. D.

Bacteria of the genus Gluconobacter have very active, membrane-bound, NAD(P)-independent, polyol dehydrogenases which stoichiometrically produce the singlestep oxidation product of polyols provided in the growth medium. These bacteria have a high respiratory quotient which is believed to result from oxidations by these dehydrogenases. These organisms grow and survive at pH values as low as 2.5 leading to speculation that their membrane-bound dehydrogenase activity provides the rapid electron flow necessary to purge cells of toxic levels of hydrogen ions. These dehydrogenases are also believed to be used for energy metabolism, and there is no clear understanding of their function in the cell metabolism. Oxidation of sorbitol in Gluconobacter oxydans ATTC 621 was studied to determine if the oxidations by the membrane bound sorbitol dehydrogenase (mSDH) were required for growth, and whether they functioned to protect the cells in low pH environments. G. oxydans required a high concentration of sorbitol in the medium, and a reduction in the concentration to 0.1% decreased the rate and extent of growth. Using mutants with decreased levels of mSDH, we found that growth rates decreased as a result of this mutation, indicating that mSDH activity was needed for growth. No changes in the specific activity of mSDH in strain ATCC 621 occurred when the cells were grown at pH 7.0, 6.0, and 4.5. However, cytochrome levels were doubled in cells grown at pH 4.5 compared to pH 6.0 and 7.0. The increased cytochrome levels did not increase the oxygen uptake of the pH 4.5 grown cells on sorbitol. Cells grown at all pH values respired more rapidly when tested at pH 4.5, and respiration decreased as the pH increased. The higher activity at lower pH values may result from increased efficiency of mSDH, which has an in vitro pH optimum of 5.2. Magnesium and calcium increased the respiration of pH 6.0 grown cells but not pH 4.5 grown cells. Less cell mass per mg of sorbitol oxidized was obtained when cells were grown at pH 4.5 compared to pH 6.0 and 7.0. However, no differences were detected in the specific activity of any of the sorbitol oxidizing enzymes. The activity of mSDH in G. oxydans is necessary for the growth of this bacterium. The mSDH specific activity is not regulated by the growth pH, but increased levels of cytochromes and decreased cell yields indicate a change in the cell's oxidative system resulting from lowered growth pH values. / Ph. D.

A general purpose computer model for the SCR is developed. The model, consisting of both a circuit analog and parameter estimation procedure, is uniformly applicable to popular computer aided design and analysis programs such as SPICE2 and SCEPTRE. The circuit analog is based on the intrinsic three PN junction structure of the SCR and is similar to Nienhus' model. The parameter estimation procedure requires only manufacturer's specification sheet quantities as a database. It employs some of the concepts developed by Hu for a SPICE2 SCR model. This uniform model, denoted the J³ SCR model, is shown to be a useful design aid through computer simulation of fault transients which may occur in a"Schwarz" converter. The transients simulated would not be observable without use of a highly accurate continuous topology non-linear SCR model such as is developed here. / Ph. D.

A three-dimensional linear stability analysis is presented for two-dimensional boundary layer flows. The method of multiple scales is used to derive the amplitude and the wave number modulation equations, which take into account the nonparallelism of the basic flow. The zeroth-order eigenvalue problem is numerically integrated to calculate the quasi-parallel growth rates which are then integrated together with the nonparallel growth rates along the characteristics of the wave number modulation equations to evaluate the n-factors. The n-factors are used to determine the most dangerous frequency. The most critical frequency is defined to be the one that yields the n-factor corresponding to transition in the shortest possible distance. This definition is used to evaluate the critical frequency for the Blasius boundary layer, a wedge flow and an axisymmetric boundary layer. The effect of three-dimensional disturbances is evaluated and found to be less critical than two-dimensional disturbances regardless of the pressure gradient, the temperature distribution of the wall and the wall geometry. The effect of heating the boundary layer is evaluated for the Blasius, Falkner-Skan and axisymmetric boundary layers. In all the cases considered, heating substantially reduces the n-factors. Results are compared with those of Strazisar & Reshotko (1978) and Nayfeh & El-Hady (1980). / Ph. D.

The purposes of this study were: (1) to determine the relationship between participants' health orientations and their nutrition knowledge, beliefs, and behavior before participation in the Red Cross nutrition course, Better Eating for Better Health, (2) to determine whether the differences between participants' pretest and posttest scores for nutrition knowledge, beliefs, and behavior were significant and positive, (3) to determine whether participant:s pretest scores for nutrition knowledge, beliefs, and behavior were significantly and negatively rela-r.ed to their respective change scores, and, (4) to determine whether participants' nutrition knowledge, beliefs, and behavior change scores can be predicted on the basis of their health orientations. A pretest-posttest design was used. A health orientations instrument consisted of three scales: health behavior, health locus of control, and health incentives. Participants' health orientations were assessed before participation in the course. Pre- and posttest measures were taken of the nutrition knowledge, beliefs, and behavior of the participants. The age, level of household income, and number of years of education of participants were used as control variables. Results indicated that health locus of control and income was positively and significantly related to pretest nutrition knowledge. All three health orientations variables were significantly and positively associated to pretest nutrition beliefs. Positive health behavior, positive health incentives and age were significantly and positively correlated with pretest nutrition behavior. Significant and positive differences were observed between the pre- and posttest scores for nutrition knowledge, beliefs, and behavior. Pretest scores for nutrition knowledge, beliefs, and behavior were significantly and negatively related to the respective change scores. Health locus of control, age, and income were significant predictors of nutrition beliefs change scores. Collectively, the predictor and control variables accounted for 52 percent of the variation in nutrition beliefs change scores. Health behavior and income were significant predictors of nutrition behavior change scores. The joint effect of the predictor and control variables accounted for 53 percent of the variation in nutrition behavior change scores. / Ph. D.

For several years organization theorists have debated the magnitude of the impact of size and technology on dimensions of organization structure. Also, management theorists have shown the importance of structure on organization goal attainment. However, no consensus has been reached concerning the interrelationship among size, structure and technology. Apparently much of the disagreement among theorists is a result of mixing levels of analysis, inadequate specification of variables, use of inadequate or inappropriate research tools and lack of controls for potentially confounding variables. The purposes of this dissertation were: (a) to provide a better understanding of the complex interrelationships among size, technology and structure; (b) to use regression analysis in an effort to better depict the relationships among those variables; and (c) to attempt to bridge some of the findings of other researchers that disagree among themselves. The study used carefully selected variables that appear to be appropriate to the level of analysis (the organization) used, and careful selection of sample organizations in order to control for some potentially confounding variables. Other potentially confounding variables were measured and their effects on size, technology and structure controlled for. The central hypotheses of the study were: (a) that technology would cause structure to differ for small firms; and (b) that the difference in structure would disappear among large firms. The findings were mixed, with some of the structural dimensions being related to both size and technology and others to neither size nor technology. The structural dimensions of formalization, specialization and number of hierarchical levels appear to be functions of organizational size, with the effects of size moderated by technology. The structural dimensions of decentralization of authority and Chief Executive Officer's span of control do not appear to be related to either size or technology. Additionally, it appears that the differences in structure attributable to technology are greater for large firms than for small firms. This finding was contrary to the hypothesized relationship. An additional significant finding of this research was that it appears to be more appropriate to refer to the relationship among given dimensions of structure and other variables rather than structure as a monolithic concept. / Ph. D.

One of the fundamental premises of financial reporting by business enterprises is that it should provide users with information that will assist them in predicting the amounts, timing and uncertainty of future cash flows of the enterprise. The requirement for alternative income measurements was partially justified by an assumed correspondence between the new information and the cash flow prediction objective. The existence of that correspondence, however, has not been precisely verified by the research to date. The overall objective of this research was to contribute additional evidence to address conflicts in the prior research findings, and additionally, to consider possible industry and firm-size effects on the ability to predict cash flow from alternative incomes. A data base was compiled from COMPUSTAT tapes (historical cost), the Parker model restatement procedures (general price-level) and the Easman data base that used the Falkenstein-Weil restatement model (replacement cost). One conclusion was that the alternative income measurements produce different cash flow forecast errors. Overall, historical cost net income produced the lowest forecast errors for two approximations of cash flow. The inclusion of monetary gains/losses and holding gains/losses in net income did not improve predictions, and in one case worsened them. Another conclusion was that a multiple linear regression model produced significantly lower forecast errors for both cash flow definitions. The simple linear and exponential regression prediction models did not produce different forecast errors. Finally, both an industry effect and a firm-size effect were identified in the prediction of working capital from operations. When net income plus depreciation was the object of prediction, an industry effect was identified but not a firm-size effect. The overall impact of these findings is that the alternative income measurements should be justified on some basis other than facilitating cash flow prediction. In fact, a random-walk cash flow prediction model performed better than any prediction based on net income. Financial accounting standards in the area of alternative income measurements should consider possible industry and firm-size differences. The choice of cash flow definition is apparently critical because different conclusions were obtained. / Ph. D.

Since its founding in the Progressive Era, public administration has focused most of its energy on the problem of executive agency administration. The study of the administration of the legislature as a distinct category of administration organization is a long-overdue step. Public administration has had “blinders” concerning the legislature. Thus even while it invokes “politics in bureaucracy,” it fails to give full breadth to the concept it has created. The task set forth for this study is to examine the distinctive administrative and management character of the legislature as a first step toward integrating its activities into a broader understanding of the inter-relationships among government institutions. Part I of this study provides a historical perspective by which to understand the legislative institution. Part I is divided into three chapters. The first analyzes the theoretical and political concepts which underlie the American legislature at the time of the founding of the nation. The second chapter examines the decline from prominence of the American legislature during the nineteenth century with particular attention given to the changing orientation that emerged during the Progressive Era. The final chapter of Part I explores the consequences of the decline of the legislature and the anti-politics and anti-legislative bias of public administration. Part II (Chapters Four through Seven) re-examines the organizational and political roles of the legislature. The first step is to create a confederated model of organization within which to study legislatures. The focus of Chapter Four is the presentation of the confederated model. Chapter Five examines the administrative and management consequences of such an organization. Chapter Six examines the political functions of the legislature with emphasis on how the model explicates those political functions. Chapter Seven examines the legislative function in the administrative processes of executive agencies. Part III represents a series of suggestions for future study that encompass four areas: theories of organization, theories of representation, legislative practice, and legislative-executive inter-relationships. / Ph. D.

This study combined the traditional concepts of cost, demand, and revenue models together with performance indicators to derive a methodology to (1) measure the performance standing of a transit company within its peer-group, and (2) improve this standing with the improvement on the values of parameters and impact factors in the methodology. To enrich the existing pool of indicators, four new basic transit variables -- vehicle hour miles, vehicle revenue hour miles, revenue capacity hour miles, and passenger hour miles have been developed. On the model building side, operating expense, unlinked passenger trip, passenger fare revenue for transit service, and transportation revenue aspects have been selected as the response variables. On the data side, UMTA Section 15 second annual data were used. Many shortcomings existed in this data set have been pointed out and possible solutions were given. With a total of 170 transit variables as the potential causal variables, various techniques were employed to reduce this size. In addition, linear as well as non-linear regression models have been derived. On the performance evaluation side, a new methodology employing the index comparison concept was proposed. An index is defined as the ratio of the difference between actual and expected values over expected value. Four sub-indexes were developed for the four operating aspects, and two overall performance indexes were derived from these sub-indexes. Because the average index value is zero, so a positive index would be better than both the expected and the peer-group values. The opposite is true for the negative case. Hence, transit systems can be ranked by the performance level through the sign and the magnitude of any index. This would form a good basis for public funding based on performance level. Besides the parameters in the models, impact factors were extracted for outliers to the models. From both parameters and impact factors, an individual transit company should be able to locate its weak areas of operation, so a consorted effort can be channelled to improve them. / Ph. D.

The purpose of this study was to investigate the effects of a special preparation program of coaching on the verbal section of the Scholastic Aptitude Test (SAT). The coaching program was designed to familiarize the students with test-taking strategies and to enhance their sequential deduction and reasoning abilities through the use of classwork as well as homework. This special preparation course covered a period of six weeks and was held directly after school. The sample for this quasi-experimental study included 170 seniors from three public high schools in a suburb of the Greater Washington Metropolitan Area who had first taken the SAT in May of their junior year and again for a second time in November of their senior year. The May SAT verbal scores served as the pretest measures and the November SAT verbal scores served as the posttest measures. An analysis was made using the regressed gain scores to see if there was a significant difference between the students who were coached for the second test and for those who were not coached. The findings of this study indicated that coaching was effective for those students who received the special preparation. Additionally, the study examined the following: (1) the effect of coaching across schools; (2) the interaction of controlling variables such as sex, grade point average, final grade in junior English, and parental education levels; and (3) the difference in regressed gain scores of those students who volunteered for coaching programs and for those students who did not volunteer when neither group received any coaching. / Ed. D.