Chemical Engineering Commons^™

Separation Via Multi-Column Ph Parametric Pumping, Wei Tai Yang

Dissertations

This thesis presents the study of multi-column pH parametric pumping, a separation technique which applies the principle of parametric pumping and uses pH as control variable. Studies emphasize the mass transfer and the capability of separation by multi-column pH parametric pumping. Many operation modes of multi-column pH parapump are developed for varied objectives of separation. A Two-pH Levels Parapump is capable of enriching the product stream with solute components; a Three-pH Levels Parapump is capable of splitting components into two product streams. The separation capability of multi-column parapump is greatly superior to that of single-column parapump. As compared to cycling …

Correlation Of Thixotropic Parameters And Related Tests Of Blood From Human Subjects, Walter Fabisiak

Dissertations

The flow behavior of human blood is an important facet of the circulatory system as it affects all of the organs of the body. The rheological properties of whole blood provide a means of analyzing the flow of red cells and plasma through the microcirculation. A recently observed rheological characteristic of whole human blood is thixotropy, a time-dependent phenomenon. This phenomenon is caused mainly by the redistribution of an aggregated form of erythrocytes, known as rouleaux, and the non-aggregated, single erythrocytes. In order to further define and analyze the thixotropic properties of blood, the Huang model is used to quantitatively …

Thixotropic Properties Of Whole Human Blood, Jen An Su

Dissertations

The rheological property of whole blood from various human subjects was studied with a Weissenberg Rheogonio-meter, modified with a continuously variable speed drive. Experimental data showed a hysteresis loop in the shear stress versus the shear rate plot and a torque-decay in the shear stress versus the shearing time plot which is under a constant shear rate. The rheological equation previously developed by Huang was employed to define the thixotropic parameters of each whole blood sample based upon the recorded rheograms.

The altered thixotropic parameters for the blood from patients with open heart surgery at different clinical stages were quantitatively …

The Continuous Non-Equilibrium Parametric Pump: A Theoretical And Experimental Study, John Lawrence Rak

Dissertations

A continuous parametric pump in which the feed and product streams flow steadily both in upflow and downflow (hot and cold temperatures, respectively) is examined theoretically and experimentally. The model system is Sodium Chloride-Water-Bio Rad AG11A8 Ion Retardation Resin, a physical system characterized by relatively slow interphase mass transfer rates. For short half-cycle times, where interphase equilibrium is not approached, separation of the salt from water is found to be enhanced by longer half-cycle times, smaller reservoir displacements, and longer adsorbant columns. In most cases, separation improves with increasing number of cycles. However, steadily degrading separation is found to exist …

Flow Of Polymer Melt Blends Through Porous Media, James Atwood Parker

Dissertations

The flow of molten polystyrene, poly(methyl methacrylate) and three blends of these polymers has been studied in a rheogoniometer and in packed beds of unconsolidated spherical glass beads. One primary purpose of the study was to determine the behavior of polymer melt blends in porous media flow. The second major purpose of the work was to develop and test a new and powerful model for packed bed flow based upon the Huang generalized rheological constitutive equations.

Rheological characterization of the pure polymers and blends was obtained using a Roberts-Weissenberg rheogoniometer. Shear and normal stresses were measured at shear rates from …

Sodium-Initiated Polymerization Of Alpha-Methylstyrene In The Vicinity Of Its Reported Ceiling Temperature, Shuenn-Long Ou

Dissertations

No abstract provided.

Distributed Parameter Sensitivity Theory To Solve Certain Reliability Problems, Moses Nee Buernor Ayiku

Dissertations

It is well known that in actual control systems there are uncontrolled parameter changes caused by aging of elements, temperature, pressure and effects of externalmedium, among others, which may impair the performance ofthe system. Hence, there is the need to develop systems that weakly react to these parameter fluctuations. Sensitivity theory has been developed to study some of these problems. Most of the investigations in this area, however, deal with problems in continuous systems modeled by ordinary differential equations. Even the recent publications on sensitivity problems in distributed parameter control systems are largely concerned with systems modeled by first order …

Preparation And Magnetic Properties Of Rare Earth Garnets And Apatites, Rostam Mondegarian

Dissertations

It has been found possible to prepare garnets with magnetic trivalent rare earth ions filling all or most dodecahedral sites while nonmagnetic Sc³⁺ ions fill all octahedral sites and magnetic Fe³⁺ ions fill all or most tetrahedral sites. Phase-pure garnets found include {RE_3-ySc_y}[Sc₂](Fe₃)O₁₂, where RE is Sm, Eu, Gd, Tb or Dy and y can be zero with Sm and Eu; {Nd₃}[Sc₂](Fe_zGa_3-z)O₁₂; and other Nd-Sc-Fe garnets of the type {Nd_3-(w+y)M_wS_cy}[Sc₂](Fe …

Separations Of Multicomponent Mixtures Via Thermal Parametric Pumping, John Daniel Stokes

Dissertations

This dissertation covers the separation of solutes from multicomponent solutions via direct mode thermal parametric pumping.

Dilute solution separations were predicted from existing binary equations by assuming the existence of pseudo binary systems, each system consisting of one solute and the common solvent. Two systems, toluene-aniline-n-heptane and toluene-acetophenone-n-heptane with a silica gel adsorbent were used to experimentally demonstrate the separation. Experimental results were in good agreement with the mathematical predictions.

For concentrated multicomponent solutions, the separation was demonstrated by the system, toluene-acetophenone-n-heptane on silica gel. The effects of mass transfer and nonlinear adsorption isotherms became significant and a numerical solution …

Characterization Of Thixotropic Materials And Modification Of The Weissenberg Rheogoniometer, Paul Joseph Orosz

Dissertations

A Weissenberg Rheogoniometer, Model R-18, was modified to give complete rheological curves without resetting the gearbox and generate hysteresis loops for time-dependent, non-Newtonian materials. This modified instrument was used to analyze a number of materials. Standard Newtonian and known time-independent, non-Newtonian materials were studied to insure the accuracy of the instrument. Results indicated that the instrument would reproduce known viscosities of these materials, give consistent results, and not display inherent hysteresis loops with non-thixotropic materials. Materials known and suspected to be thixotropic: silicone grease-oil mixture, montmorillonite clay, and blood were tested. All displayed the characteristic hysteresis loop usually associated with …

The Interpretation Of Infrared And Raman Spectra Using Pattern Recognition, John Martin Comerford

Dissertations

An automatic classification of chemical compounds by computer processing of digitized spectral data is presented. The classification system is based on a branch of artificial intelligence known as supervised learning, and used binary linear classifiers to identify compounds as alcohols, esters, ethers, ketones or compounds containing double bonds.

Each of the 1117 spectra in volume one of Sadtler's Standard Raman Spectra was coded using a scale from 0 to 9 in the range from 4000 to 200 cm^-1. One hundred and twelve readings were taken on each spectrum. These data were then examined using pattern recognition techniques, and …

A Nonlinear Viscoelastic Model, Yon-Li Shangkuan

Dissertations

A nonlinear viscoelastic model has been developed to describe the non-Newtonian viscosities and the primary normal stress differences of high polymers at steady-state shearing flow.

It has been demonstrated that the Huang-Shangkuan model gives the best representation of the experimental data for a wide range of shear rates. In the high shear rate region the Huang-Shangkuan model is distinguished among other models by its capability to predict the nonNewtonian viscosities and the primary normal stress differences Which the other models fail to predict.

Continuum mechanics, Lodge's network theory and Rouse's theory provide specific information in developing our model. The theoretical …

Effect Of Gas Temperature Gradients And Radiant Heat Transmission On Kinetic Model Behavior, Richard W. J. Robertson

Dissertations

Satisfactory methods to predict radiant heat transmission in enclosures containing a radiating gas at uniform temperature are available. These methods have been traditionally used in solutions of kinetic models.

Kinetic models are strongly temperature dependent with a difference of 10°K able to double the reaction rate. In the present investigation, calculation techniques which make allowance for the non-uniformity of gas temperatures in an enclosure are applied to the kinetic models. The furnace problem considers only the radiation section with the assumption that detailed knowledge of combustion and fluid flow pattern within the enclosure is available.

If the gas space in …

Representation And Characterization Of Thixotropic Fluids, Huei-Hsiung Wang

Dissertations

Thixotropy is a time-dependent rheological behavior of a group of fluids which are characterized by an isothermal reversible breakdown induced by a mechanical disturbance. Based on this definition, a mathematical model of reversible degradation kinetics is set up. Its development leads to two equations which represent quantitatively the hysteresis loop and torque-decay curve. These equations consist of five independent parameters with their physical meanings. These parameters can be used to characterize the properties of thixotropic materials.

The original Weissenberg Rheogoniometer was modified to measure the thixotropic behavior of blood with the step change and the ramboid change of shear rate. …

The Effect Of Ultrasonic Vibrations On Heterogeneous Catalysis, William Lintner

Dissertations

The effect of ultrasonic vibrations on the vapor phase decomposition of cumene to benzene and propylene was investigated employing silica-aluminum cracking catalyst.

The catalytic reactor consisted of a 1 cm. diameter stainless steel tube containing a 20 in. long preheater and a 4 in. long catalyst chamber. The catalyst bed was irradiated from above by means of an ultrasonic horn which transmitted acoustical energy directly into the vapor.

The reactor was run at temperatures of 650°F. and 1050°F., frequencies of 26,000 cps and 39,000 cps, feed rates of 20 to 600 gms./hr., power outputs of 0.5 to 1.3 watts/cm.^{2 …}

The Preparation Of Cis- And Trans-1,2-Dimethoxyethylene. The Study Of The Cis-Trans-Rearrangement And Evaluation Of Equilibrium Constants, James T. Waldron

Dissertations

Equilibrium constants for the mercuric acetate-catalyzed reaction, cis-CH₃ OCH=CHOCH₃ D trans-CH₃ OCH=CHOCH₃, have been determined in the liquid and vapor phase over the temperature range 30° - 175°C by gas chromatography analysis. A novel synthesis of the cis- and trans-isomers of 1,2-dimethoxyethylene is discussed. From a screening of 29 catalysts, mercuric acetate, mercuric benzoate, and mercuric salicylate were found to be favorable isomerization catalysts. For the liquid phase reaction,

ln K = -779.8/T + 0.6748

with ΔH° = +1.549 ± 0.019 Kcal/mole
and ΔS° = +1.34 ± 0.05 e.u./mole

Similarly, for the vapor phase reaction, …

Structure And Magnetic Properties Of Rare Earth Garnets, Milan R. Kokta

Dissertations

This study deals with preparation and magnetic properties of garnet compounds containing rare earth ions and scandium ions on two crystallographic sites: the dodecahedral and the octahedral. A number of compounds of the types {R_3-yr_y}[r_x Ga_2-x](Ga₃) O_12' {R₃}[Sc₂](Fe_z Ga_3-x) O_12' {R_3-y Sc_y}[Sc₂] (Fe₃) O_12' and {R_3-y r_y)[r₂ (Fe_z Ga_3-z) O_12' where R stands for large rare earth ions such as Nd³⁺ and Pr³⁺, …

The Oxidation Of Carbon Monoxide By Magnesium Aluminate, James A. Whelan

Dissertations

In this research the catalytic oxidation of carbon monoxide was investigated on magnesium aluminate catalysts, MgO:xAl₂O₃, with five different compositions, x, ranging from 1.0 to 3.0. The reaction was run at temperatures ranging from 500 to 600 °C. with radioactive carbon monoxide as the tracer. An experimental technique has been devised for the analysis of unreacted CO which takes into account a correction for the solubility of CO in CO₂.

Four mathematical models were postulated to explain the mechanism of reaction. The models were examined against experimental data by means of non-linear least squares …

Local Mole Fraction Equations For The Excess Free Energy Of Mixing, Jose Mario Marina

Dissertations

An extensive study of local mole fraction equations aimed at obtaining a two parameter expression for the Excess Free Energy of miscible and immiscible systems has been undertaken.

Initially our approach was to modify existing equations by substituting those parameters reflecting interaction between like molecules by the pure component energies of vaporization. This resulted in a one parameter modification of the three parameter Wilson equation, which correlates data poorly and a two parameter modification of the NRTL equation which correlates binary miscible data with fair accuracy. A modification of the Scatchard-Hildebrand equation, where mole fractions are substituted by local mole …

A Kinetic Study Of The Anionic Polymerization Of Neopentylethylene Oxide, Albert Edward Meisinger

Dissertations

Kinetic data for the anionic polymerization of bulk neopentylethylene oxide were determined. The initiator used for this study was potassium t-butoxide. Polymerization runs were made at temperatures of 39.9, 60.0 and 80.3°C using monomer to initiator ratios of 50/1 and 20/1.

The polymerization reaction was found to follow pseudo first order kinetics up to about 60% polymerization and second order after this. The energy of activation for the propagation reaction was found to be 17.4 ± 1.2 K cal/mole and 18.5 ± 1.5 K cal/mole, respectively, for the pseudo first order and second order portions of the polymerization. The value …

Continuous Esterification Of Lactic Acid With N-Butyl Alcohol, Robert Dix

Dissertations

A model is proposed for the reactions occurring when an aqueous 30% lactic acid solution is contacted with a primary alcohol, normal butanol. Kinetic and equilibrium data for the esterification reactions of monomeric lactic acid and dimeric lactic acid were determined in a series of experiments using an ideal overflow back-mix reactor. The variables studied were reaction temperature and catalyst concentration.

It was determined that the significant reactions occurring within this system are the esterification of monomeric lactic acid with n-butanol and the esterification of dimeric lactic acid with n-butanol. Other reactions that may be postulated to occur within the …

A Study Of The Dynamics Of Gas Adsorption In An Air Fluidized Bed, William Charles Zalewski

Dissertations

The dynamics of gas adsorption was studied in an air fluidized bed containing activated alumina particles. The adsorption studies made with a fixed bed and in the transition region between minimum fluidization velocity and 2.0 times minimum fluidization velocity, compliment work done at higher velocities. With adsorption, particle motion controlled the overall dynamics of the fluidized bed. A different approach in applying the two phase fluidization model was necessary to satisfactorily describe unsteady state adsorption in fluidized beds. Experimental and theoretical results were compared in frequency response plots to obtain a rigorous comparison. Good agreement was obtained for flow rates …

Simulation Of Periodic Tank Reactors, Noshir Pirojshaw Mistry

Dissertations

Normally it is assumed that the steady state mode of operation is most desirable for the design of the chemical reactor system. However it appears that this assumption may not be correct in many cases.

In the present work disturbances of various types were externally created and forced on a system comprising an isothermal continuous stirred tank reactor. The effects of these purposefully created disturbances were investigated by mathematically modelling the system and simulating it on a digital computer.

The change in reactor performance, as defined by the percentage change in the production rate from the steady state value, can …

Boiling Heat Transfer In The Presence Of Electric Fields, Ronald Francis Lovenguth

Dissertations

The effects of a non-uniform, radial D.C. electric field on the natural convection and nucleate boiling regimes in saturated pool boiling and on the peak heat flux phenomenon were determined for trichlorotrifluoroethane, carbon tetrachloride, dichloromonofluoromethane and chloroform using as a heat transfer surface a 0.02 inch diameter platinum wire.

Bubble departure diameters for the nucleate boiling region were measured by photographic means as a function of the electric field intensity at the heat transfer surface.

The application of an electric field was found to have a significant effect on the natural convection mode of heat transfer and also the peak …

Viscosity-Density Correlation Of Newtonian Liquids, Melvin Leonard Druin

Dissertations

The viscosity of monatomic liquids was modeled by an equation derived from the kinetic theory of gases. Viscosities may be calculated from data on density and molecular weight of the liquid. In adapting this relationship to polyatomic liquids, a single correction factor was developed for each of five series of homologues; n-paraffins, n-1 -alkenes, n-alkylcyclohexanes, n-alkylbenzenes and n-alcohols, to account for the deviations of the calculated viscosities from those reported, extending over a one- to three-hundred degree range. The factor is a function of reduced temperature relative to the normal boiling point, T_rB. A single equation for each …

The Generalized Virial Equation Of State, Ghanshyam R. Patel

Dissertations

A generalized three parameter virial equation of state has been developed and tested for seven pure gases having different molecular characteristics. The equation has also been tested for more than thirteen binary gas mixtures using three different mixture rules. The final equation is as follows:

Z = 1 + B(T)/V + C(T)/V² + D(T)/V³ + E(T)/V⁴ + VF(T)/e^aV + VG(T)/e^bV

The expressions for E(T), F(T), and G(T) along the critical isotherm were derived in terms of critical properties and two constants, a and b which appear in the sixth and seventh terms in the above …

Relationships Between Some Properties Of Pure Homologous Organic Liquids, Herbert Rudolph Kemme

Dissertations

The vapor pressures of eleven primary straight chain alkyl chlorides and eleven primary straight chain alcohols between C3 and C16 were determined within a range of 5 to 760 mm Hg. These data were obtained by determining the boiling points of the pure materials at various pressures by using differential thermal analysis. The boiling points were determined with a precision of -.1 degree Centigrade at a 95 per cent C.I. The Antoine equation was used to analytically describe the data. The constants for this equation were determined by a multiple linear regression technique for each individual compound. The heats of …

Kinetics Of Hydrogen Reduction By Manganese Dioxide, Herbert Eugen Barner

Dissertations

Samples of synthetic pyrolusite were reduced in hydrogen at various partial pressures in the temperature range of 200° to 500°C. Most reduction experiments were conducted using a Pyrex vertical-tube reactor, in which small beds of porous particles (0.07 to 0.21 mm.) or single porous pellets of the oxide were suspended. The reaction kinetics were followed by recovering and weighing the water product formed during measured time intervals, and the intermediate reduction products were identified by X-ray diffraction analysis.

The data show that reduction proceeds through the sequence MnO₂->Mn₂O₃->OMn₃O₄- …

Kinetics Of The Lactic Acid-Butyl Alcohol Esterification Reaction, Joel Howard Kaplan

Dissertations

Kinetic and equilibrium data for the esterification reaction of monomeric lactic acid with normal butanol were determined in a series of experiments utilizing a batch stirred tank reactor. The variables studied were temperature and catalyst concentration. The kinetic data were successfully represented by the integrated equation for a second order reversible reaction.

Rate constants were obtained at three temperature levels and four catalyst levels. The observed rate constants in the catalytic reaction were linearly correlated with catalyst concentration and also satisfied the Arrhenius criterion. The activation energy and frequency factor for the uncatalyzed reaction were determined to be 13,190 calories …

Hydrotropic Extraction Of Hydrocarbon Mixtures, Michael Jay Ram

Dissertations

The solubilities at 25°C of selected aromatics and straight chain alkanes in hydrotropic solutions of sodium xylene sulfonate and sodium cymene sulfonate were studied. The results of this investigation are shown on distribution diagrams relating the solubilities of alkane and aromatic in each phase.

Two methods were investigated to predict the experimentally determined solubilities. The semi-empirical solubility parameter approach resulted in answers that were extremely low. A purely theoretical approach involves the calculation of dispersion forces between molecules. An equation for predicting solubilities has been derived so that it is applicable to four component systems. This method results in values …