This thesis discusses topics in the field of process engineering that have received much attention over the past twenty years: (1) conceptual process synthesis using heuristic shortcut methods and (2) process integration through heat-exchanger networks and energy-saving power and refrigeration systems. The shortcut methods for conceptual process synthesis presented in Chapter 2, utilize Residue Curve Maps in ternary diagrams and are illustrated with examples of processes for separating azeotropic mixtures. This chapter constitutes a comprehensive review of the most relevant literature of the last twenty years and was itself accepted for publication in Industrial and Engineering Chemistry Research in the Spring of 1994. We demonstrate the usefulness of RCMs as both a tool for teaching the complex techniques necessary for separating azeotropic mixtures and as a practical engineering aid for conceptual design of separation processes. We also give proper clarifications of some traditional misconceptions and contradicting recommendations in the literature. The introduction to and demonstration of process-integration topics in Chapters 3 through 6 are of value to both new and more experienced process engineers. The in-depth treatment of meaningful case studies in Chapters 4, 5 and 6 contain much useful information concerning complex heat-integration and process-retrofit problems. Chapter 4 discusses aspects of multiple-pinch heat-integration problems and ways to tackle them with two of the latest commercial process-integration softwares. Chapter 5 presents a review of and an extension to an Ethylene Plant Retrofit case study taken from the ADVENT Examples Manual (Aspen Technology, 1993), while Chapter 6 does the same for an Ethylene Plant Retrofit case study published earlier by the CACHE Corporation in 1985. / Ph. D.

Despite repeated attempts, no normative theory of public administration has emerged that fully and satisfactorily answers questions about the role of public administration, and public administrators, in the process of governance. This dissertation argues that such questions are unresolvable because they are framed in terms of overly simplistic systems metaphors relating to machines and organisms. When theories are framed in terms of these metaphors, they lead inexorably to dichotomies between politics and administration, policy and implementation, and between the society and its government. The dissertation attempts to "reframe" our concept of governance in terms of another metaphor that supports a view of governance as a process that is deeply interrelated and interconnected with its social environment. / Ph. D.

The complex, IrH₂(PMe₃)₃Cl (1), was previously found to be, not only unexpectedly water-soluble but also an effective homogeneous catatyst for the hydrogenation of unsaturates in water. The results of extensive ³¹P NMR studies on the aqueous system of (1) indicate that (1) is in equilibrium with the iridium(III) dihydrido “aquo” complex, [IrH₂(PMe₃)₃(H₂O)]⁺, and not the μ-chloro bridged complex, { [IrH₂(PMe₃)₃]₂Cl}⁺ (2), as previously reported. The calculated K_eq value for the aqueous equilibrium is (0.0037 ± 0.0003) M. Thermodynamic data (ΔH = 30.8 kJ/mol, ΔS = 56.0 J/(Kmol), and ΔG = 14.1 kJ/mol) obtained from variable temperature ³¹P NMR studies are consistent with the proposed equilibrium system. The complexes IrH₂(PMe₃)₃X (X = O₂CPh (3), I (4), and Br (6) were synthesized and examined. The complexes IrH₂(PMe₃)₃X (X = H₂O and F) could not be isolated. (3) was determined to dissociate completely in water to form the iridium(III) dihydrido “‘aquo” complex, [IrH₂(PMe₃)₃(H₂O)]⁺, seemingly explaining the greater catalytic activity of (3). Solubility of the halo complexes decreased from moderately soluble (1), to slightly soluble (6), to very slightly soluble (4). The solubilities of (4) and (6) were too low to allow quantification of their equilibria. Finally it was observed that linear relationships exist between the electronegativity of the ligand, X, and the ¹H and ³¹P NMR chemical shifts of the hydrides and the phosphines for the complexes, IrH₂(PMe₃)₃X. These relationships are consistent with the findings of Birnbaum. / Ph. D.

Geomagnetically induced currents (GIC) could saturate a transformer core. Two significant effects are the abnormal stray flux in transformers and extremely large harmonic contents in excitation currents, which can lead to serious equipment damage and power system misoperation. Such incidents have occurred during the March 1989 K-9 solar magnetic disturbance. This dissertation starts with a systematically study of transformer magnetization under GIC. It reviews both dc and ac saturation patterns of five transformer core designs. Magnetic fields along various traverses for dc excitation are presented. Impedance matrix entries of a single phase transformer are compared for normal and dc operations. New observations have been formed based on the simulation results. The study helps to reveal the fundamental transformer magnetization mechanism under GIC in order to assess potential stray flux heating possibilities of geologically vulnerable transformer units. Based on the finite element analysis, an improved method of modeling transformer excitation under dc bias using equivalent magnetic circuit is developed. There are two unique points in this approach: first, information of 3D finite element magnetic flux distribution analysis is used to construct and verify the circuit model; second, the effect of the transformer tank: is included The model is capable of simulating transformer excitation currents under different levels of dc bias with good accuracy. As a consequence, the complete variations of excitation current harmonics with respect to an extended range of dc bias are revealed. The sensitivity of transformer winding impedances and core loss on the excitation characteristics are examined. The saturated transformer under no-load and various loading conditions is simulated. A laboratory test is performed on a small scale transformer and compared with the model results. Excitation harmonics generated from dc biased three phase transformer banks with different types of equivalent loads are also simulated The effect of both unbalanced dc excitations and unbalanced loads are investigated The results of this study contribute in understanding transformers as harmonic sources and the impact on power systems during a geomagnetic disturbance. / Ph. D.

The vibrational energy propagating in straight fluid-filled elastic pipes is carried by the structure as well as by the internal fluid. Part of the energy in the system may also transfer from one medium to the other as propagation occurs. For various types of harmonic disturbance, this study demonstrates that, whether the propagating energy is predominantly conveyed in the shell or in the fluid, large attenuations of the total power flow may be achieved by using an active control approach. As the shell and fluid motions are fully coupled, the implementation of intrusive sources/sensors in the acoustic field can be also avoided. The approach is based on using radial control forces applied to the outer shell wall and error sensors observing the structural motion. A broad analytical study gives insight into the control mechanisms. The cylindrical shell is assumed to be infinite, in vacuo or filled with water. The first disturbance source investigated is a propagating free wave of circumferential order n=0 or n= 1. The control forces are appropriate harmonic line forces radially applied to the structure. The radial displacement of the shell wall at discrete locations downstream of the control forces is minimized using linear quadratic optimal control theory. The attenuation of the total power flow in the system after control is used to study the impact of the fluid on the performance of the control approach. Results for the shell in vacuo are presented for comparison. Considering the breathing mode (n=O), the fluid decreases the control performance when the disturbance is a structural-type incident wave. Significant reductions of the transmitted power flow can be achieved when the disturbance is a fluid-type of wave. Regarding the beam mode (n=1), the fluid increases the control performance below the first acoustic cut-off frequency and decreases it above this frequency. / Ph. D.

Multivariate statistical methods have been strongly recommended in behavioral research employing multiple dependent variables. While the techniques are readily available, there is still controversy as to the proper use of the methods that have been developed for analyzing and interpreting data after finding a significant pairwise difference with a multivariate analog of the two group t-test, known as Hotelling's T². A Monte Carlo simulation was conducted to investigate the relative power of four post-MANOVA tests under violations of multivariate homoscedasticity and normality. The four methods for analyzing multivariate group differences following a significant Hotelling's T² were: (1) univariate F; (2) Bonferroni; (3) multiple Bonferroni; and (4) simultaneous F. Depending on the conditions examined, either the univariate F test or the multiple Bonferroni procedure was shown to be the most powerful for detecting a true difference between two groups. The following are the major conclusions drawn from the investigation: (1) Power levels of post-MANOVA tests remain constant under violations of multivariate normality, however, they change considerably in the presence of heterogeneity; (2) The univariate F test provides the most liberal power levels and the simultaneous F test provides the most conservative, regardless of sample size, effect size, distribution shape, and degree of violation; (3) As the size of the effect increases, the rate of correct rejections of a false null hypothesis increases; (4) As sample size increases, the rate of correct rejections of a false null hypothesis increases; (5) Regardless of heterogeneity level, power is always larger at larger group size levels; and (6) Within each group size level, power decreases as heterogeneity increases. Analytical comparisons show simultaneous F tests have the least power, Bonferroni methods to be intermediate, and univariate F tests most powerful under violations of multivariate heterogeneity. / Ph. D.

Spontaneous combustion occurring in inaccessible areas of underground coal mines is often intractable. Even though routine inspection and/or continuous monitoring help detect the incubation of spontaneous heatings, they may not be able to identify the locations with accuracy. Moreover, implementation of remedial measures is difficult. A new approach to ventilation system design to overcome the problem is investigated in this dissertation. Ventilation layouts are analyzed to identify potential problem areas and nullify the probability of fire occurrence. The focus is directed to longwall gobs. The changing gob characteristics, especially the varying degree of consolidation at different parts of a gob as the face moves, is considered. Analytical studies and computer modeling show that bleederless ventilation in retreating panels is promising. The W -system of ventilation is most suitable. However, there may be difficulties in maintaining the middle entry in a Wsystem / Ph. D.

An initial activity in the instructional design process is an assessment of learner characteristics such as prior knowledge. Although this step is important for the instructional design process, Reiss and Morley (1993) found that only about half of the practicing instructional technologists they surveyed always performed some kind of learner analysis. The reasons for not conducting a learner analysis included lack of time and lack of knowledge about how to do such an analysis. Concept mapping has been proposed as a convenient tool for assessing learners’ prior knowledge (Jonassen, Beissner, & Yacci, 1993; Novak & Gowin, 1993). It has been said that a concept mapping procedure can be quickly developed and then conveniently administered to learners (Jonassen et al., 1993; Novak & Gowin, 1993). However, there is no evidence supporting the reliability or validity of concept mapping as a way to measure learners’ prior knowledge. The purpose of this research was to investigate the reliability and validity of concept mapping as a tool to assess learners’ prior knowledge. Students in a graduate-level statistics class and an undergraduate level engineering class were administered concept mapping and multiple-choice tests before and after instruction. The interrator reliability, internal consistency, content validity, face validity, concurrent validity, and construct validity of the concept mapping procedure were then examined. Overall, the data do not support the reliability and validity of the concept mapping procedure used in this study. However, the reliability and validity levels achieved by the concept mapping test were comparable to the multiple-choice test developed by the classroom instructor. It may be that concept mapping is no less reliable and valid than other forms of classroom assessments. Nonetheless, the concept mapping procedure used in this study can not be recommend as a practical measure of students’ prior knowledge. In addition to the poor reliability and validity, the concept mapping procedure is difficult to learn and the scoring procedure is difficult to use. In the end, the user will have to weigh the results of this study and judge the adequacy of concept mapping for its intended purpose. / Ph. D.

The active control of structures is a diverse field of study, with new applications being developed continually. One structural system, which is often not considered a dynamic system, is the floor of a building. In many cases the dynamics of a floor system are neglected in the design phase of a building structure. Occasionally, this omission results in a floor which has dynamic characteristics found to be unacceptable for the intended use of the building. Floor motion of very small amplitudes, often caused by pedestrian movement, is sometimes found objectionable by occupants of the building space. Improving an unacceptable floor system's dynamic characteristics after construction can be disruptive, difficult and costly. In search of alternative repair measures, analytical and experimental research implementing active control techniques was conducted to improve the vibration characteristics of problem floors. Specifically, a control scheme was developed utilizing the measured movement of the floor to compute the input signal to an electromagnetic actuator which, by the movement of the actuator reaction mass, supplies a force that reduces the transient and resonant vibration levels. Included in the analytical component of this research is the development of a mathematical model for a full scale experimental test floor. This model is studied, using a matrix computation software, to evaluate the effectiveness of the control scheme. The experimental component of the research serves two purposes. The first is the verification of the system behavior assumed in the analytical component of the research. The second is the verification of control system effectiveness for various excitations, control gains, and actuator locations on the experimental test floor and six additional floors. / Ph. D.

We study the Korteweg-de Vries-Burgers equation. With a deep investigation into the spectral and smoothing properties of the linearized system, it is shown by applying Banach Contraction Principle and Gronwall's Inequality to the integral equation based on the variation of parameters formula and explicit representation of the operator semigroup associated with the linearized equation that, under appropriate assumption appropriate assumption on initial states w(x, 0), the nonlinear system is well-posed and its solutions decay exponentially to the mean value of the initial state in H1(O, 1) as t -> +". / Ph. D.