Cells growing in stirred bioreactors exist in a complex fluid mechanical environment. A number of forces act on the cells in the reactor, including fluid shear stresses. If agitation is sufficiently rapid, these forces may be lethal to the cells. In this study, the effects of well defined fluid shear on cell damage were investigated in a rotational couette viscometer. The shear sensitivity of the cells was modulated by the age of the culture. For cells that experience a prolonged stationary phase, the cells were quite sensitive to shear for both young and old cultures. If the stationary phase was short, the resistance to shear was higher throughout, and declined slightly with increasing culture age. The shear sensitivity of the cells was also modulated by specific components of the cytoskeleton. Disruption of the microfilaments made the cells more sensitive to shear, while disruption of the microtubules had no effect on shear sensitivity. Shear sensitivity also depended on energy metabolism in the cells. Inhibiting respiration increased shear sensitivity, and inhibiting glycolysis caused a further increase in shear sensitivity. Addition of fetal bovine serum to the culture medium made the cells more resistant to shear in a dose dependent manner. Addition of the pluronic polyol F68 to culture media had no effect. Polyethylene glycol increased shear sensitivity. Subjecting the cells to extreme agitation over an extended period resulted in a population of cells that grew more readily at high agitation rates. This subpopulation had a higher specific growth rate and less shear sensitivity than unselected cells.

In part one, correlations between viscosity and proton spin-lattice relaxation time are developed for CO$\sb2$ - n-Hexadecane mixtures in equilibrium with their vapor-phase in the vicinity of critical points. A microscopic interpretation of relaxation phenomena is presented based on the Rate Processes Theory$\sp{12}$. It is found that by comparing with n-Hexadecane relaxation times at the same thermodynamics conditions, local motions of n-Hexadecane molecules increase when CO$\sb2$ molecules are added. In part two, it is shown that for two fluids with similar interaction potentials, at a given pressure and temperature, the ratio of the molar densities is equal to the inverse of the ratio of the molar isobaric heat capacities. This relation is extended to mixtures and is applied to several hydrocarbons and mixtures. Differences found between the two ratios would suggest that the two fluids do not have similar interaction potentials.

The effect of process conditions on coal pyrolysis and char reactivity is systematically studied using the thermogravimetric reactor equipped with in-situ video microscopy imaging (TGA/VMI). This system provides a complete time-registered record of the history of single coal particles as they are sequentially pyrolyzed and combusted in the reactor. Three coals are investigated: Illinois #6, Utah Blind Canyon, and Wyodak-Anderson seam. An image analysis procedure was developed to monitor the transient swelling pattern of the two plastic coals (Illinois and Utah). Particle swelling increases with increasing pyrolysis heating rate and increasing particle size. When pyrolyzed in reactive atmospheres, these coals exhibit less plasticity and less "bubbling", but they swell more. The maximum devolatilization rate occurs during the stage of vigorous "bubbling." Since the Wyodak coal is not plastic, it does not swell during pyrolysis. Process conditions affect char ignition behavior. Particles will ignite more easily when the observed reaction rates are high and heat removal rates are low. During combustion in the presence of intraparticle diffusional limitations, we observed that large char particles and chars produced at high pyrolysis heating rates ignite more easily. Increased particle sizes slow the heat removal rates, while high pyrolysis heating rates produce chars with larger macroporosities and macropore surface areas thus enhancing the reaction rates. Chars produced in reactive pyrolysis atmospheres appear to be more reactive and ignite more easily. Experiments at low temperatures show that the pyrolysis heating rate, particle size, and pyrolysis atmosphere do not affect the reactivity pattern in the kinetic control regime. We also developed a steady-state mathematical model for char particle ignition. Model parameters were obtained from structural measurements for the Illinois #6 chars. The model predicts that the ignition temperature decreases with decreasing gas flow rate and increasing pyrolysis heating rate, increasing oxygen concentration and increasing particle size. Model predictions are in excellent agreement with our experimental data.

Liquid triglycerides, the major component of cooking oils, have been found difficult to remove from synthetic fabrics during washing. The relatively strong adhesion force between triglycerides and fabric and their high molecular volumes make detergency mechanisms which work well for other soils and cotton fabrics relatively ineffective with surfactants commonly used in washing products. It is likely that a process for effective triglyceride removal would involve a solubilization-emulsification mechanism. Intermediate phases such as microemulsions or liquid crystals form at the surface of contact between surfactant solution and soil. These intermediate phases solubilize the soil and are subsequently emulsified into the washing bath. Because secondary alcohol ethoxylate surfactants have double tails of varying lengths, the hydrocarbon portion of surfactant films should be more disordered than for linear alcohol ethoxylates used in previous work and hence more capable of solubilizing triglyceride molecules. Equilibrium phase behavior of systems containing water, triolein, and secondary alcohol ethoxylates showed that a D or microemulsion phase which solubilized significant amounts of triolein formed at temperatures as low as 25$\sp\circ$C. In previous work with pure linear alcohol ethoxylates and triolein the D phase had formed only at temperatures above about 55$\sp\circ$C, which are undesirably high for washing synthetic fabrics. Based on the earlier studies, formation of the D phase would be expected to promote soil removal from synthetic fabrics by a solubilization-emulsification mechanism. Even for a rather hydrophilic secondary alcohol ethoxylate surfactant, slightly below its cloud point, solubilization rate and capacity are much greater than those for comparable linear ethoxylates, and complete solubilization of oils rich in triolein is possible. Liquid triglycerides typically occur as mixtures with long chain polar compounds such as alcohols or fatty acids. Contacting experiments for alcohol-rich oils revealed a mechanism involving spontaneous emulsification which provides a means for soil removal different from that found previously in other systems. Newly developed fiber contacting experiments with drops initially attached to individual polyester fibers confirmed that little oil remained on the fibers when the emulsification was extensive.

A new method to estimate the properties of electrolyte solutions has been outlined in this work. The models for electrolyte solutions at the Bonn-Oppenheimer level have always been perceived to be very complicated to solve by either integral equation theories or Perturbation theories. The present work identifies simpler BO level models called Square Well Simple Civilized model (SQWSCM) and Square Well Water Simple Civilized Model (SWSCM). The properties of SWSCM model have been obtained by simulations and hydration numbers have been found to be comparable to experimental results. In order to obtain an analytical solution for these models a Thermodynamic Perturbation type approach has been outlined. The appropriate reference fluid for the TPT approach has been identified. The properties of this reference fluid have been obtained by simulations.

The internal pore structure of chars derived from many bituminous and sub-bituminous coals can be best described by bi-modal pore size distribution. Their macropores, which account for nearly all the porosity, are interconnected spherical cavities with diameters as large 100 or 200 microns for 500--750 micron particles. Most of the internal surface area of these chars, however, is associated with micropores that are usually smaller than 30 A. In order to elucidate the effect of process conditions on the internal pore structure of coal-derived char particles and ultimately their overall reactivities, staged and sequential combustion algorithms are designed using thermogravimetric reactor equipped with in-situ video microscopy imaging (TGA/VMI). Our experiments showed that coal-derived char particles treated with higher pyrolysis heating rates have more open macropore structure than those treated with lower heating rates. At low combustion temperature where the reaction was kinetic controlled, the impact of the macropore structure on the overall reactivity of char particles was insignificant since all the internal surface area associated with micropores were accessible to the oxygen. At higher combustion temperature, however, the macropore structure of the char particle had a strong effect on its overall reactivity. Chars with more open macropore structure and larger macropore surface area exhibited higher reactivity. Also, combustion experiments showed that more open macropore structure and higher macropore surface area favored particle ignition, a transient phenomenon characterized by luminous flame engulfing the particle, which caused sharp increase of the overall reactivity of char particles. The development of the generalized grain model helped us to describe mathematically the mass and energy transfer during the char combustion process. The macropore structure was modeled as a network of interconnected spherical cavities. The walls separating these cavities consist of homogeneous assemblies of microporous grains made of carbonaceous material. The numerical analysis revealed that in the regime of diffusional limitation, a more open macropore structure could reduce the diffusional resistance inside the macropores. Therefore, it enhanced the accessibility of the micropores surface area to the oxygen and ultimately led to higher overall reactivity of the char particles.

A quantitative penetration scan method was used to study rates of dissolution of pure, noncrystalline anionic surfactants in water. The displacement of phase boundaries from initial surface of contact was found to be proportional to the square root of time, indicating the importance of diffusion. For some surfactants studied such as Aerosol OT (AOT) and 7-phenyl tetradecane sulphonate, myelinic figures grew from the initial surface of contact between surfactant and water toward the aqueous phase. A simple model was developed which included both this swelling and diffusion in the rest of the surfactant-containing region. The usual penetration scan method involving semi-infinite phases was supplemented by a novel modified scan in which only a thin layer of surfactant was used. With the combined results it was possible to obtain effective diffusivities of the liquid crystalline phases of AOT and of the two lamellar phases of 7-phenyl tetradecane sulphonate. Values were of order 10-10 m2/s. Videomicroscopy was used to investigate the mechanisms and rates of dissolution for a system containing the pure nonionic surfactant C12E 4 and the soap sodium oleate. A microinjection technique was used to inject drops of surfactants or surfactant mixtures into water. Although C 12E4 itself does not dissolve in water, dissolution was observed when drops of its mixtures with sufficient oleic acid were injected into alkaline buffer solutions. Formation of sodium oleate during the dissolution process made the surfactant mixture more hydrophilic and hence soluble. A lamellar phase formed upon injection and dissolved by a shrinking core mechanism. A hanging drop slide technique was developed and used to study disintegration of single granules consisting of many zeolite particles bound together with liquid nonionic surfactant. For pure nonionic surfactants and their mixtures, granules disintegrated below the cloud point of the pure surfactant or mixture. Disintegration did not occur when the neat surfactant developed viscous myelinic figures upon contact with water. Nor was it observed when an aqueous phase coexisted with a surfactant-rich L1 phase or L3 (sponge) phase at equilibrium. Similar behavior was observed for commercial nonionic surfactants and their mixtures.

In this thesis, a new finite element method, 4-field Galerkin/Least-Squares method, is presented to solve viscoelastic flow problems. The 4-field GLS naturally includes the SUPG and PSPG terms to stabilize the oscillations caused by advection-dominated terms. In addition, it introduces a new variable L = ∇v, so that the second order derivative of v is avoided, and the basis functions can be chosen as piecewise linear functions. This feature substantially enlarges the space of the basis and weighting functions. The Galerkin terms in this formulation guarantee that the traction term n·T appears naturally by integration by part, which serves as an important boundary condition for free surface flow. Moreover, the 4-field GLS successfully circumvents the LBB condition on velocity and conformation fields. The 4-field GLS is tested with a carefully defined set of benchmark problems for both Newtonian and non-Newtonian fluid. It is found to be robust, accurate and efficient.

In this thesis, a technique to assemble nanoparticle-assembled capsules (NACs) onto a planar substrate has been demonstrated. NACs are micron-sized spherical capsules produced from organic and inorganic materials. New sensing materials of various length scales are needed for numerous sensing needs of today, and NACs on substrate are interesting to investigate. Several parameters were optimized to achieve maximum surface density of capsules (0.09 NACs/mum 2). NACs are best adsorbed onto negatively charged surface. The NaCl concentration in the poly(diallyldimethylammonium chloride) and poly(styrene sulfonic acid) solutions used to coat the glass coverslip substrate should be at least 1 M. In addition, a minimum of one bilayer of PDADMAC/PSS is required. The deposition time required to achieve the maximum density was at least 10 minutes. Finally, aging NACs before assembling them on the substrate decreased NAC coverage on the surface which could be attributed to change in NACs' surface charge.

Dipolar interactions significantly influence the phase behavior of many systems of interest to the biochemical, chemical, petroleum and polymer industries. For example, the solution behavior of amino acids, small peptides, polar solvents and co-polymers have potential applications for biochemicals, water-soluble polymers for paints and coatings, and surfactants. By considering molecular-level interactions, the phase behavior of a large range of systems can be predicted. Using structural analysis and thermodynamics, the essential role of polar functional groups on solubility of small biochemicals is established. An accurate model for fluid mixtures with multiple polar functional groups is developed. Results from a systematic experimental study on the aqueous solubility of amino acids and dipeptides as a function of temperature, salt type, and salt concentration are analyzed. Changes in temperature and residue sequence have the most substantial effect on solubility. Structural analysis shows that intra and intermolecular association largely influence the behavior. For small molecules, end effects dominate the behavior but should be less important for many biochemicals. Values for enthalpic changes from the solid to the infinitely dilute liquid state for the dipeptides of asp and gly are reported. An accurate model for mixtures of polar fluids, in which any number of groups and/or any component of the mixture may be polar, is developed by applying the u-expansion to a reference fluid mixture of polar and non-polar spheres. An in-depth parameter study of this model, named Polar SAFT, for a homologous series of ketones indicates that the model parameters have physically reasonable values. A methodology is proposed for developing a group-contribution approach for the model. The ability of Polar SAFT to accurately predict the effect of multiple dipolar groups and molecular shape on the phase behavior of binary mixtures of polar and non-polar components is exemplified by application to a series of ketone/alkane mixtures. Using only pure component parameters, Polar SAFT accurately represents these systems, indicating the predictive capability of the model and the importance of explicitly accounting for polar interactions. For alkane/copolymer (poly(ethylene-co-methyl acrylate)) solutions, Polar SAFT accurately predicts the polar co-monomer content and solvent effects on cloud point behavior.