Engineering Commons^™

Mathematical Modeling Of Carrier Mediated Mass Transfer Through Liquid Membrane Systems, Keng Chao Wang

Dissertations

Dispersed liquid membrane systems are double emulsion drops. Two immiscible phases are separated by a third phase which is immiscible with the other two phases. The liquid membrane systems were classified into three types: (1) carrier mediated mass transfer, (2) mass transfer with reaction in the receiving phase, (3) mass transfer without any reaction involved. Copper extraction, phenol removal and solvent extraction were used as typical examples for each type of the membrane systems in the derivation of their mathematical models. Models with or without the consideration of film resistances were developed and compared. The models developed in this study …

Mixing Effect On Chemical Reaction In Liquid Phase, Ming-Teh Hsu

Dissertations

Mathematical models for the mixing phenomenon are proposed in this study. First model deals Newtonian and non-Newtonian fluid without chemical reaction. The new terminology " degree of mixing " is define in this model for the time-dependency of mixing toward its completeness. The velocity profile and boundary conditions are given, then the degree of mixing can be calculated by the mathematical model. The degree of mixing is influenced by fluid motion and it is function of time.

Second model deals with first-order reaction effected by mixing. A mean fractional conversion is defined to investigate the rate of bhemical reaction. Results …

Mathematical Modeling Of Unsteady State Photo-Polymerization, Rong-Fa Liang

Dissertations

Mathematical modeling of unsteady state photopolymerization in an isothermal batch reactor has been investigated. An analytical solution of the distribution of active polymers as a function of reaction time has been determined. It is verified that the quasi-stationary state approximation is valid in the photopolymerization process.

The free radical polymerization of styrene is forced periodically by on-off UV light regulation to the reactor. The effect of operating condition, the ratio of light-off period to light on/off period, on the polydispersity and molecular weight distribution are theoretically and numerically investigated. Significant broadening on molecular weight distribution can be obtained during the …

The Effects Of Pressure On The Kinetics And Mechanisms Of The Bod Reaction, Peter Sereico

Dissertations

The research was concerned with the kinetics and mechanisms of BOD reduction due to pressurization. The initial investigations involved attempts to reproduce and interpret the results of previous investigators. Thereafter, actual wastewater samples were pressurized and changes in the wastewater characteristics were analyzed and recorded. Based on the findings, possible mechanisms for creating the changes noted were proposed.

To test the mechanisms considered, samples of pure compounds were prepared and pressurized. The results of this analysis eliminated all of the mechanisms but the actual one. The mechanism responsible for changes in BOD profile under pressure conditions is the hydrolysis of …

Mathematical Modeling Of Distillation Operation From Non-Equilibrium Approach, Wen-Dow Pan

Dissertations

A new method for mathematical modeling of a distillation operation from non-equilibrium approach has been studied. The primary purpose of the study was to develop a model to simulate the mechanism of mass transfer between a continuous phase and the bubbles of a dispersed phase in a distillation column. The second major purpose of this work was to utilize and test the model of estimating the tray efficiency.

Distillation was considered to be purely a mass transfer process, where the less volatile component is transferred from vapor to liquid phase, and the more volatile component from liquid to vapor phase. …

Use Of An Optical Probe To Measure Bubble Characteristics In Gas Fluidized Beds, Thomas Tai-Pai Chu

Dissertations

A novel optical probe has been developed and used for on-line monitoring of the bubble characteristics in a three-dimensional gas fluidized bed. The probe sensor has a major dimension of 1.8 cm, and contains an LED and a photo-cell separated by a gap of 2.5 mm. Coupled with a non-inverting comparator circuit with hysteresis as a noise filter, the probe has been very effective in characterizing the size distribution, shape and velocity of gas bubbles.

A 96 liter rectangular fluidized bed was used, containing glass beads with a size fraction of 355μ to 250μ. Air was the fluidizing medium, with …

Decentralized Optimal Control With Application To Dynamic Routing In Computer Communication Networks, Ning Wang

Dissertations

This research considers the dynamic routing problem of computer communication networks in the framework of decentralized control theory. The routing dynamics are modeled in terms of a state equation with multiple controllers. Routing, or control of message flow, is formulated as an optimal control problem with multiple decision makers. Each decision maker may have access to different set of information and work cooperatively to optimize a common system performance index.

Necessary and sufficient conditions for optimality are derived for a system with a deterministic and a stochastic traffic patterns under a linear information structure and a quadratic performance index. The …

Mathematical Models Of Unsteady Operation Of A Packed Column, Jen-Fu Chao

Dissertations

Analytical solutions of differential equations applicable to extraction, ion exchange, or adsorption processes in packed beds are presented. Results are given for three different cases. The first case accounts for adsorption phenomena only. The second one includes surface adsorption on particles and the effects of longitudinal dispersion in the bed. The third one deals with diffusion in particles and longitudinal dispersion in the bed. In the mathematical modelling of these three cases, a linear equilibrium relationship between the solute in the liquid phase and solute in the solid phase is used. The first case is solved using the single boundary …

The Settling Of An Arbitrary Number Of Spherical Particles Arranged On The Corners Of A Regular Polygon In A Viscous Fluid, Eric Robert Bixon

Dissertations

The creeping motion equation has been solved for the case of planar arrays of spheres settling under the influence of gravity in a viscous fluid. The solution is a general solution which applies to an arbitrary number of spheres. All particles will lie at the corners of a regular polygon. Thus, two particles side by side, three particles in an equilateral triangular array, or four spheres in a square array will be special cases of the general solution.

The solution has been obtained by a unique application of the method of reflections. Only a first correction to the drag has …

Optimization Of A New Linear Fm Detector Using Digital Signal Processing Techniques, Edward J.A. Kratt

Dissertations

This dissertation describes and synthesizes a new member of the family of FM detectors introduced earlier by Klapper and Kratt. A salient property of these detectors is low delay with excellent sensitivity. The emphasis in the new detector is on the ease of digital implementation. In addition, the new detector is also extremely linear. In congruence with the other Klapper-Kratt detectors, it makes use of zero group delay elements, balance at RF, quasi-synchronous detection and carrier cancellation. The Performance of the detector is mathematically analyzed under the conditions of a modulated input wave, sinewave [sic] interference, and noise. The results …

The Effect Of Ultrasound On The Hydrolysis Of Carbohydrates, Adel A. Khamis

Dissertations

Acid hydrolysis of dextran and cellulose were studied with and without irradiation with ultrasonic waves of different frequencies (17 - 150 KHz), and powers (0.4 - 200 w/cm²). In the case of both materials, the hydrolysis reaction was found to be first order with respect to the activity of hydrogen ions in the reaction medium. Weight average molecular weight was evaluated at different durations of the reaction course. The reaction rate of dextran was found to be proportional to the weight average molecular weight raised to the power 4/3, and raised to the power 4 for cellulose.

The …

Application Of Fuzzy Theory To Pattern Recognition, David Usechak

Dissertations

Piecewise curve approximation is used to describe boundaries of objects in pictures and waveforms. The method consists of linear and quadratic piecewise polynomial approximations in which the error must not exceed a predetermined cost threshold. A fuzzy Bayes model is used to determine if a breakpoint exists within an interval I_n or between intervals I_n and I_n+1 and to determine whether these intervals can be merged for data compaction reasons. In order to achieve these objectives a new fast algorithm has been proposed which gives good curve/object fitting. This algorithm uses a technique for generating generalized inverse …

Broadband Base Isolated Asymetrically Fed Vhf Antenna, Peter Edward Cunningham

Dissertations

Antennas presently being used for vehicular military VHF communications are narrowband. New generation frequency hopping radios, however, require broadband antennas. The antenna must be base isolated in order to reduce undesirable pattern nulls and impedance variations caused by currents induced on the support structure. Physical constraints limit the antenna length to three meters while operating from a frequency of 30 MHz to 88 MHz.

To satisfy the above requirements a model of a broadband, base isolated, cylindrical antenna less than three meters long was analyzed and built. Equations for the current distribution as a function of the physical parameters were …

Motion Of Viscous Liquid In Rotating Cylinder, Chicheng Wu

Dissertations

A computer model for the withdrawl and buildup of the fluid from the pool bounded on the horizontal, rotating, cylindrical surface has been developed. For a incompressible Newtonian fluid, the model is based upon the modified SOLA-SURF algorithm to solve the finite-difference form of Navier-Stokes equations on primitive variables. A hybird of centered and partial donor cell differencings is applied to the momentum convective flux. In each time cycle, the cell velocity is adjusted by the pressure corrector and iterates to satisfy the equation of continuity. The free surface position is approximated by a surface height function derived from kinematic …

Removal Of Fluoborate From Electroplating Rinse Water By Ion Flotation, Ray Haralson

Dissertations

A problem exists in the removal of fluoborate from electroplating waste rinse water. The normally used waste treatment methods are not effective and the vacuum evaporation process now being tried is expensive and energy intensive. Experiments were conducted and an alternative treatment process which shows substantial removals of the fluoborate was developed. This can be effectively done using ion flotation techniques. A broad range of surfactants were screened for usefulness in this process and it was found that an aliphatic amine acetate was usable in this process. Operating parameters for the process were investigated, and the removal mechanism was determined …

Fractionation Of Multicomponent Mixtures By Staged Sequence Cyclic Process And Parametric Pumping, Charles Omotayo Kerobo

Dissertations

The continuous fractionation of multicomponent fluid mixtures has been experimentally and theoretically investigated by staged sequence cyclic process and parametric pumping operating in the direct thermal mode.

A multicolumn staged sequence cyclic process for the separation of solute mixtures was developed. The criteria necessary for the continuous fractionation of a system of n solutes with n+1 columns arranged in a series operated with n+1 cyclic variables is presented. The feasibility for practical application of this process was demonstrated by fractionating the model system, O-xylene-Anisole-n-heptane on silica gel. The separation was modeled by one column staged sequence experimental data and by …

Separation Of Proteins Via Ph Parametric Pumping With Electric Field, Helen Conway Hollein

Dissertations

A new semi-continuous parametric pumping process for the separation of protein mixtures has been developed, based on cyclic variation of pH and electric field. The model system used for this process consisted of a mixture of human serum albumin and human hemoglobin in contact with CM Sepharose cation exchanger. Experimental results show that the protein separation via the pH parapump with electric field is two to three times greater than the results which are obtained in batch chromatography or via either single-column or multi-column parapumps with cyclic variation of pH and ionic strength.

The separation in the new process depends …

Remote Attitude Measurement Techniques, Frank John Elmer

Dissertations

A method has been developed for solving practical problems which can be expressed in terms of physical geometry. These problems often involve combining directional information observed by remotely located sensors reported in their own respective local coordinate systems. To transform this information into a common coordinate system, the attitude of the sensors must be measured with respect to this common coordinate system.

Physical geometry is a generalization of mathematical -geometry where objects define the endpoints of figures composed of ensembles of lines. A probabilistic approach has been taken which is based on the fundamental assumption that the objects can be …

Crimp-Type Electrical Connectors, Ted Lai-Che Kuo

Dissertations

Three types of surface conditions (plain surface, plain surface with oxidation inhibitor, and toothed surface) and four types of environmental gases (air, nitrogen, hydrogen, and oxygen) were used to study the performance of electrical connectors installed on aluminum conductors. All of the connectors were placed insealed vessels which allowed the desired type of gas to flow at a steady rate. The connectors were then current cycled.

For the connections prepared with plain surfaces, the connectors deteriorated equally fast in air, nitrogen and hydrogen. Only the connectorsexposed to oxygen showed a higher deterioration rate than the others.

Connections prepared withhaving plain …

An Experimental Study Of Multiple Steady States In A Photopolymerization Reactor, Chih-Ning Kuan

Dissertations

An experimental study of photosensitized free radical polymerization of styrene in both batch and continuous stirred tank reactors is presented. Each reactor was run under both adiabatic and isothermal conditions. Multiple steady states were investigated. Exact multiplicity and uniqueness criteria for the above systems were derived and a mathematical model developed to correlate the results.

For both adiabatic and isothermal continuous stirred tank reactors operating in the metastable state regions, the conversion and polymer molecular weight are greater than the corresponding lower steady state operations. At a given conversion level, the reaction time for both adiabatic and isothermal continuous stirred …

The Entrainer Effect On Azeotropic Distillation Column Design, Charles Ming-Hsiao Tsai

Dissertations

A rigorous multistage distillation model was developed for use with non-ideal multicomponent systems. A subsidiary computer program was also developed to handle the problem of two liquid phases after condensation of a vapor.

Using the program developed, entrainer entry location and rate effects have been investigated via computer simulation for azeotropic distillation columns. The specific example used to verify the procedure was an ethanol dehydration column using benzene as the entrainer. The results indicate that the entrainer should enter the column two to five theoretical stages above the feed. The optimum entrainer rate was also determined.

The overhead vapor product …

Separation Technique On Proteins Via A Ph-Parametric Pump : A Theoretical And Experimental Study, Ura Pancharoen

Dissertations

The separation of protein mixtures via pH-parametric pumping was investigated both theoretically and experimentally. A simple system consisting of one column packed either with cation or anion exchanger was first considered. A system of parapumps was then developed with more columns which were connected in series and packed alternately with cation and anion exchangers. Various methods of operation of parapumps are discussed. Enrichment and spliting of protein mixtures were examined. In most cases, the separation factor was defined at a steady state condition and was improved by increasing the number of cycles and columns.

Computational methods for predicting both Batch …

Analysis Of Oscillations In Nonlinear Systems Using Multiple Input Describing Functions, Frederic Lee Swern

Dissertations

Sufficient conditions for oscillation as well as absence of oscillations are presented for a class of systems containing one lumped linear element and a differentiable nonlinearity. The results are obtained by estimating the error inherent in using a describing function analysis. Contraction type arguments are used to show common topological properties of the describing function solution and the balance of first harmonic terms of the system.

After discussing the describing function method, two theorems are presented regarding existence or nonexistence of oscillations from homotopic considerations. A graphical method for examining systems with power law nonlinearities is given using a parameter …

Deposition Of Particles In Vertical Conduits Due To Electrostatic Charge, Diffusion, And Gravity, Melvin Wilbur Gelber

Dissertations

This investigation was made to determine the effect on the deposition of fine particles in a vertical channel and in a vertical tube due to the influences of electrostatic charge, diffusion, and gravity acting in the direction of flow. The flow considered was laminar, incompressible and steady.

The governing equations for the fluid phase were derived from the Navier-Stokes equation and the continuity equation while the equations for the particle phase were derived from Poisson's potential equation and the continuity equation. Since the governing equations are non-linear partial differential equations the solutions were developed using numerical methods.

The flow patterns …

Mathematical Modeling And Analytical Solutions Of Dissolved Oxygen And Biochemical Oxygen Demand Profiles Under Three-Dimensional, Unsteady-State Conditions, Uing Woong Kim

Dissertations

Mathematical models describing the temporal and spatial distribution of Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD) for both pervious and impervious channel conditions in 3-dimensions have been constructed, and their analytical solutions were obtained. The solutions were implemented through the application of a digital computer, and their results are presented.

It has been found that there are significant differences in terms of DO and BOD distribution with respect to time and space in relatively deep and wide channels, thus necessitating the use of a 3-D, unsteady-state model.

Investigations Of Gate Turn-Off Structures, Hans Werner Becke

Dissertations

Research and Development was done on gate turn-off devices. The aim was i) to improve turn-off capability without compromise of turn-on, on-state, and useful temperature range, ii) to implement "safe" turn-off.

A) The dependence of the electrical device characteristics on cathode width for an optimized vertical structure was determined. Fall times of 100 to 200 nsec and risetimes of <400 nsec were simultaneously obtained for average current densities of 53 A/cm² @ T_j = 125°C. From spreading resistance analysis the fast t_r and t_f response is shown to be a consequence of proper Au-distribution in the active device volume.

From transient analysis it is concluded that for safe …

Statistical Averaging In Position Determination By Holography Under Turbulence Conditions, Paul Aloysius Mcgovern

Dissertations

An investigation of several, disparate phenomena is conducted with the aim of developing a novel surveying system capable of overcoming the limitations imposed by turbulence in modern surveying. This method incorporates standard holographic techniques and time domain statistical averaging of survey data.

Some pertinent characteristics of atmospheric turbulence are reviewed, and the restrictions imposed on standard surveying practices by such turbulence are identified. A model for the turbulent medium is proposed on the basis of previous work and several theoretical results are summarized and extended.

On this basis the technical characteristics of the proposed technique are developed and each step …

Correlation And Prediction Of Vapor-Liquid Equilibrium In Electrolytic Solutions, Anil Krishna Rastogi

Dissertations

Two expressions for the excess Gibbs free energy are presented which correlate and predict vapor-liquid equilibrium and the mean molal activity coefficient of an electrolyte in a ternary mixture containing water and either MeOH or EtOH. The proposed equations take into account coulombic forces between ions and the physical interaction forces between ion-solvent and solvent-solvent molecules in a solution.

Model #1 is a combination of an extended Debye and Huckel equation and the local composition of non-random two liquid (NRTL) model. A ternary mixture requires six adjustable binary parameters to predict activity coefficients. These six parameters are evaluated from three …

Separation Of Proteins Via Continuous Ph Parametric Pumping, Steve Wu

Dissertations

This dissertation covers the separation of proteins via recuperative mode pH parametric pumping. Continuous pH parametric pumping separations using the model system haemoglobin and albumin on a CM-Sepharose cation exchanger have been experimentally and theoretically investigated.

The pH parametric pumping system has a feed containing the protein mixture to be separated, introduced alternately to the top and bottom of the column. The top and bottom products are withdrawn from the apparatus during the bottom and top feed, respectively. Both equilibrium and nonequilibrium cases were considered, and theoretical results agreed with the experimental data.

Buffer concentration, flow rate, reservoir displacement, and …

Parametric Pumping With Ph And Ionic Strength : Enzyme Purification, Zikri Mostafa Ahmed

Dissertations

The work on separation and purification of proteins by parametric pumping has been restricted so far to pH parametric pumping where the difference between the iso-electric points of the components to be separated is apparent. The present work establishes the foundations for the continuous separation and purification of proteins (including enzyms) that have similar or very close iso-electric points by using the ionic strength as a driving force for the separation process. This technique has commercial advantages over batch processes.

It was found that the most promising technique for separating alkaline phosphatase consists of the following three major steps: (I) …