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Expert operates his contract research & development small business incorporated in 1990 in Saint Paul, Minnesota, USA. Expert's professional experience spanning over four decades in chemical engineering has focused around the broad areas of particulate/multiphase processes and rheology.

Chemical engineering is a combination of unit operations and unit processes. Unit operations are physical operations such as size change operations (size reduction, size enlargement), separations (staged, continuous), mixing, and transport (momentum, heat, mass). Unit processes are chemical reactions -
inorganic/organic and homogeneous/heterogeneous. There is hardly any unit operation or unit process involving a fluid phase that is not influenced by fluid 'rheology'. Expert has extensive experience studying the rheology of various material forms encountered in the process industry - powders, semisolids, suspensions, emulsions, foams, aerosols, solutions, and melts.

Expert's laboratory has a state-of-the-art rheometer equipped with major accessories - different geometries (cone-plate, parallel plate, concentric cylinder); bicone and Du Nouy ring for surface and interfacial rheology; peltier plate for temperature control; environmental test chamber for work with polymer melts. Rheological testing capabilities include - stress controlled, rate controlled; rotational, oscillatory; steady, transient; temperature and frequency sweeps, steady shear, thixotropy, stress relaxation, creep-recovery, and more. Glass transition temperatures, gelation points, scaling factors (fractal dimensions, aspect ratios) of structures (micro-/nano-) are among the many characteristics studied frequently. Expert has used rheology as the basis to solve problems as phase separations (syneresis, creaming, sedimentation) and other types of instabilities in various structured fluids.

Expert has optimized processes and products/formulations based on rheology where appropriate. Expert has used a variety of instruments - SEM, enviro-SEM, cryo-TEM, PCS, SAXS, AFM, etc. - to supplement rheological evaluations. He has used image analysis of the dispersed (particles, droplets, bubbles) phase to determine size distributions (mean Sauter diameter, polydispersity index), shapes (circularity, sphericity), etc. and quantified the influence of these and other relevant parameters as contact angles (dynamic, micro) and surface tensions on dispersion rheology.


Expert has successfully developed two types of viscometers for his industrial clients - a pipeline viscometer (for coal-water, coal-oil) and a rotational viscometer (for aqueous dense suspensions like those of barytes, ferrosilicon, galena, magnetite). The slurries have been characterized as pseuduplastic or dilatant usually with a
yield stress. Rheological studies have helped in estimating the type and optimal content of rheology modifiers (including modifiers of particle size distribution) to stabilize the suspensions and also in the design of hydraulic transport systems and densemedia cyclone operations. Expert has also built a capillary viscometer to
characterize several power-law fluids - pseudoplastic and dilatant - used in his studies of the hydrocyclone. His was probably the first detailed study published on this aspect of hydrocyclone flow pattern.

Expert is well experienced in the preparation (high-pressure homogenization, ultrasonic processing) and characterization of emulsions (both micro- and nano-). He has used bicone and Du Nouy ring geometries to study surface/interfacial rheology. Syneresis (phase separation) is a very common challenge Expert has addressed successfully. Expert has used a variety of techniques as appropriate - SEM, enviro-SEM, cryo-TEM, PCS, SAXS, AFM, etc. - to supplement rheological evaluations of dispersions (emulsions included) for physical stability. He has used high-speed video-enhanced microscopy to study the kinetics of droplet coalescence. Expert has correlated rheological parameters of emulsions with parameters as droplet size distribution, dispersion phase fraction, contact angle, surface tension, and others as appropriate.

Expert has used rheology as a tool to assess the quality of solid particulate dispersions produced in colloid-mills and high-pressure homogenizers. In addition to rheological evaluations, Expert has measured a variety of surface/interfacial characteristics - wettability (using dynamic and micro- contact angles); critical micelle concentration (using adsorption isotherms); and surfactant layer thickness (SEM, SAXS, PCS) and stiffness (AFM) - in optimizing dispersions for physical stability.

Expert is well experienced with the rheological characterization of food products of different forms - powders (Jenike shear cell), semisolids (doughs, cake-mixes, jams/jellies, cheese, sour cream), suspensions, emulsions, foams (whipped-cream, ice-cream, cake-mixes, egg-white, beer, espresso coffee), syrups, etc. In the case of food emulsions and foams Expert has studied interfacial rheology as well as image analysis of droplets/bubbles where appropriate/feasible.

Expert has studied the melt rheology of various thermoplastic polymers and their composites with nanomaterials. He has used both dynamic as well as steady-shear measurements as appropriate.

Expert has studied the rheology of various silicone fluids for biomedical applications including use as lubricants.

Expert is well experienced with the formulation optimization of surface modifiers including paints and coatings based on their rheology. A well formulated coating has the desirable rheological characteristics – shear thinning to provide low roller spatter and good film build at high shear rates while maintaining a low viscosity at low shear rates for improved flow, gloss, and leveling. The choice of a rheology modifier is tricky as the zero shear viscosity should be adequately high to keep the suspension stable in storage.



Expert has studied the rheology of protein precipitates and related the parameters shear modulus, plasticity, and apparent viscosity to the recovery efficiencies of centrifugation and ultrafiltration. Also Expert has used rheology to study the flocculation and deflocculation states of a coacervate; denaturation temperature of a protein solution; and the optimal storage temperature to keep a protein solution fully frozen so as to minimize its transportation costs. Expert is knowledgeable in the area of foam fractionation of proteins.




Expert is well experienced in the development of formulations, products, and processes for the pharmaceutical industry in the area of novel drug delivery systems. Expert has successfully addressed several rheological challenges encountered in pharmaceutical processing - powder mixing, surface coatings, capsule filling, extrusion, injection molding, surgical implants, spray-drying, drug-in-adhesive mixes, inhalation products, ocular formulations, in situ gelling systems/depots, transdermals, therapeutic foams, etc. Major problem areas addressed include - production efficiency as well as product uniformity, physical stability, and drug delivery performance.



Expert has used rheological characterization to evaluate/optimize different cosmetic formulations/products - and product forms for their performance and physical stability. Examples of products include - tooth pastes, lotions, creams, ointments, lipsticks, nail polishes, deodorant sprays, and shampoos.

Expert has consulted for the ceramic industry in the area of rheology. Expert has used rheology in formulating various products and in optimizing the unit operations involved in their production - wet mixing/milling, shape forming, and coating/deposition. Projects have involved development of desired physical properties in the processed materials (powder, green body, surface coating, etc.) as well as structural/rheological characterization of particle-fluid systems (suspensions, injection molding mixes, etc.). Expert's initial exposure to the subject of fine ceramics has been as an elective during his undergraduate curriculum in chemical engineering. Then his doctoral work in fine particle technology has enhanced his strengths in the subject area leading to several industrial consulting opportunities. Expert has edited the Manual of Chemical Technology, the second of the four volume series includes chapters on ceramics, refractories, cements, glass, electrothermal products, etc. Expert has authored a chapter on refractories for this volume.

Expert is well experienced with various mechanical unit operations involving dispersions where rheology matters - wet milling, agglomeration, mixing/homogenization, spray-drying, physical separations, hydraulic transport, surface coating, etc. as well as those involving dry powders - dry milling, air classification, blending, compaction, seiving, pneumatic transport, storage bins/hoppers, etc. Expert has used various state-of-the-art instrumentation for characterizing fine/ultrafine particulates (size, shape, relative density, contact angles, surface charges) and multiphase systems (rheology, stability, surfaces/interfaces). Expert has evaluated/optimized various binders for producing pharmaceutical compacts, agglomerates, granules, etc. with predictable/controllable properties as strength, porosity, and tortuosity.

Expert is experienced in the generation of nanoparticles by various methods - top-down (milling) and bottom-up (precipitation) - and dispersion of these nanoparticles in aqueous and non-aqueous media and in polymeric matrices. Characterization of these dispersions involved the use of microscopic (SEM, TEM) as well as rheological techniques. Application areas include - nanofluids, nanocoatings, nanofilms, nanofibers, and nanocomposites.

Expert's experience in the area of comminution has been both as a researcher and as a consultant. In his research on densemedia separation of ores in a hydrocyclone, Expert used a variety of size reduction equipment, including - hammer mill, roll crusher, vibration mill, ball mill, planetary ball mill, and fluid energy mill - for preparation of feed material to the hydrocyclone pilot plant. Expert used vibratory screens to separate the milled material into different size fractions. Expert used a variety of analytical techniques for determining the size distributions of the milled materials. These techniques include - centrifugal classification, air-jet seiving, sedimentation balance, surface area instruments, and optical microscopy. He developed his own techniques for determining the degree of mineral liberation using sink-float analysis involving organic heavy liquids. Expert fitted the data of particle size distributions and relative density distributions into appropriate mathematical models for use in process modeling and optimization. Expert has consulted for the ceramic and mineral industry on the choice of appropriate particulate processing equipment for their applications. Expert performed pilot-scale tests on these equipment and made recommendations. Expert worked on various pilot scale equipment and mastered both theory and practical aspects of the unit operations involved. Expert computed breakage and selectivity functions from the milling data and determined grinding efficiencies for use as objective functions in optimizing the milling process. Expert has considerable experience with the design and scale-up of fluid-energy mills. He has consulted extensively for the industry on fine grinding of mica, and a variety of food, pharmaceutical, pigment, and ceramic materials.

Expert is experienced in optimizing the spray drying operation of food, pharmaceutical, polymer, and various industrial products based on the rheology of the suspension, the emulsion, or the solution being atomized. Rheology influences the spray pattern, the droplet size distribution, and the movement of the wall material or the the diffusion of the solvent to the surface, thereby influencing the morphology and the particle size distribution of the microcapsules or the powder particles produced.

Expert has significant research contributions in the area of hydrocyclones for density based separations of coal and minerals. He was the principal consultant on a multimillion dollar project on physical desulfurization of fine coals sponsored by the Department of Energy. The project team included six corporate partners, four
of them being major coal producers in the USA.

Expert was among the first to recognize and report on the effects of the non-Newtonian nature of suspensions involved in the operation of a hydrocyclone as a classifier or a densemedia separator. He characterized dense media as power-law or yield power-law fluids and incorporated this aspect in a phenomenological model he developed for hydrocyclone performance. Expert used aqueous solutions of carboxymethyl cellulose to represent pseudoplastic fluids and aqueous starch solutions to represent dilatant fluids and made indepth studies of the hydrocyclone reporting for the first time the effect of non-Newtonian nature of the fluid
on hydrocyclone operational characteristics as flow patterns, volume split, pressure drop, and classification efficiency. His work has clarified several performance features of the hydrocyclone and at the same time negated certain prevailing notions concerning its flowpatterns.

Expert during his academic affiliation had the opportunity to set up a flow characterization/visualization laboratory. His work involved laser-doppler velocimetry to study the three-directional fluidflow patterns including turbulence levels in hydrocyclones of different designs and fluid systems Newtonian and non-Newtonian. Also he used a highspeed video system to study particle trajectories in a hydrocyclone. Expert's work is well referenced in literature as the first to examine in detail the role of fluid rheology on the flow pattern in the hydrocyclone and consequently on the performance of the hydrocyclone as particle separator based on size, shape, or density.

Expert has developed a novel froth flotation process carried out in the centrifugal force field of a hydrocyclone. He patented the process that he developed during his doctoral work at the Indian Institute of Technology Madras. The process offers the advantage of a specific capacity 50-200 times (for a specified efficiency of
separation) offering enormous cost savings compared to that of conventional froth flotation devices for mineral beneficiation, newsprint deinking, treatment/recycling of wastes, remediation of contaminated soils, removal of volatile organic compounds from ground waters, and clean-up of oil spills, and various other applications where froth flotation is applicable. Expert has considerable experience with the selection of surfactants as collectors and frothers for this application. Expert has further developed the theoretical aspects of bubble-particle attachment and detachment under shear conditions. Colloid and interface chemistry and contact angle measurements have been an essential part of the froth flotation process development. Expert used a high speed video system to determine the induction time for a bubble to get attached to a particle to be on the order of a few milliseconds. Then, the several minutes of residence time in conventional flotation cells is the time spent by the particle-laden bubble to travel to the surface of the tank or column for collection at the top. The process carried out in the centrifugal field reduces this residence time considerably saving costs.


Expert's experience in the area of pulp and paper technology includes - rheological characterization of paper pulp; rheological optimization of a paper coating formulation; separation of impurities from paper pulp and fractionation of wood pulp fibers based on fiber length using a hydrocyclone; newsprint deinking by froth flotation in a hydrocyclone.

Over the years, Expert had the opportunity to work on a number of industrial projects in the area of particulate/multiphase processes covering almost the entire spectrum of unit operations and processes. Some examples of projects include - selection of a binder of optimal rheology for agglomeration, effect of dispersion
rheology on the physical characteristics of the spray-dried powder, rheological considerations in optimizing surfactant type and content in nanomilling, effect of densemedium rheology on the separation efficiency of a hydrocyclone used for beneficiating different ores and minerals, detection of sol-gel transition in a food product
to determine the cause of a pump failure, design of a pipeline transportation system based on slurry rheology, optimization of powder mixing in a ribbon blender for product uniformity in tablet manufacture, and many more.

Expert has worked on a number of projects in the area of environmental engineering - color removal from effluent waters from a dye manufacturing plant; newsprint deinking by froth flotation in a hydrocyclone; desulfurization of fine coal in a densemedia cyclone; oil-water separation by froth flotation in a hydrocyclone; rheological characterization of waste sludge to determine its filtration characteristics; removal of volatile organic compounds from ground waters and industrial waste waters in a froth flotation cyclone; design of a hydrocyclone system for dissolved air flotation; recycling of waste materials by physical separations based on size, shape, density, and surface characteristics; optimization of a multiple hydrocyclone system.

Expert has studied the rheological characteristics of various liquid (e.g. waste cooking oil, crude glycerine, molasses) materials having good potential for use as additives in solid biofuel production utilizing different biomass materials (e.g. sawdust, straw, hay, grass cutting). Natural binders (e.g. starch, corn flour, and potato flour) keep biomass fuel chemically stable. Molasses is also a good binder specifically with the herbaceous biomass. An understanding of the rheological behavior of the liquid additives allows anticipation of different phenomena during solid biofuel production such as spreadability of the fluids in the powder mixture, flow and compactability of the powders during pelleting at different temperatures and pressures, penetration and retention of additives in pellet voids during and after pelleting.

The aim of the study has been to examine and compare the rheological properties of selected liquid and semisolid materials and to predict their physical behavior during different stages of solid biofuel production. The information is used further to select the most appropriate raw materials for biofuel production.

The liquid additives increase energy content, reduce energy consumption in briquetting/pelleting operations, decrease dusting, avoid segregation, and improve the physical quality of the final product.

In-depth studies of therapeutic foams - evaluated different foam generation techniques; studied bubble size distributions by high-speed digital video-microscopy and image analysis; rheological characterization - bulk/interfacial; formulation development for controlled/predictable stability and improved performance. Rheological optimization of a biomedical lubricant. Formulation and process development of a rheologically stable inhalation product with controlled and predictable drug delivery.
Rheological solutions to challenges (product non-uniformity and wastage of the valuable active) in a pharmaceutical capsule filling operation. Optimal coating formulation for controlled drug release tablets based on rheological considerations.Rheological characterization and image analysis of nanoparticle dispersions for biomedical applications. Evaluation of high-pressure homogenizer performance based on product rheology. Rheological evaluation of a dairy product to determine the root cause for failure of a heat-exchanger. Optimizing surfactant dosage in the colloid milling of pigment particles using rheological approach.Evaluation, engineering, and development of advanced liquid cyclone processes for physical desulfurization of fine coals. A comparative study of nanofluids for heat transfer rate enhancement.