DEPARTMENT OF CHEMICAL ENGINEERING
Indian Institute Technology, Bombay
Ph.D. Topics for year 2005-2006
Prof JHUMPA ADHIKARI
1. Molecular simulation study of miscibility behaviour and microstructure in compound semiconductor alloys (PS/TA)
The proposed work envisions a molecular simulation study of the miscibility behaviour and the microstructure in compound semiconductor alloys. The Tersoff potential model is the interatomic interaction potential for the InxGa1-xAs alloy system, which is selected as a representative example of these alloys. The alloy will be modelled for a range of compositions (considering x from zero to unity) and temperature from 100 K to the measured upper critical solution temperature (UCST). The bulk phase and thin films are both considered in the study. The microstructure is characterized by properties such as lattice constant and bond length, which are useful to measure as a way to connect to experiment and thereby, validate the model. The local composition as predicted by simulations can help in predicting the effect of microphase segregation that is difficult to quantify experimentally. The existence of even small microphases can have a disproportionate effect on the optoelectronic properties of these alloys. The interfacial tension between the coexisting solid phases can be used to predict the evolution of microstructures in these alloys. The most significant aspect of this study will be the attempt to explore connection between the interfacial tension and microphase segregation in these alloys. Monte Carlo simulations in the isothermal-isobaric semigrand ensemble are used for simulation purposes. InxGa1-xAs has been chosen due to its special properties, which enable its extensive use in fibre optic communications. Though this work is modelling the InxGa1-xAs alloy system, it can be easily be extended to other III-V and II-VI compound semiconductor alloys.
Funding agency : DST approval pending
Duration of funding : Three years (pending approval from DST)
Prof. JAYESH BELLARE
1. Physico-chemical and structure-bioactivity relationship in Bhasmas (TA)
Co-Guides: AK Suresh/SG Kane
Our recent work shows that nanoparticulates are present in bhasmas, which are a product of traditional medicinal system. Interesting biological activity has also been documented for the
first time in model systems. We would like to do an in-depth, exhaustive, and through study of a wider range of such products to establish a mechanism of action in current model systems and newer biological models, and relate them to the physico-chemical nature of the material.
2. Microstructure and microdynamics in soft matter and complex fluids. (TA)
Soft solids and complex liquids are important states of matter that are in-between the traditional words of materials science and biology. They are of immense importance in the emerging technologies of microstructure engineering, biotechnology, food processing and the like. Examples range from complex liquid crystals, microemulsions, liposomes, foams, membranes, and bioresorbable prosthesis to common materials like tea, butter and ice cream. Soft solids and complex liquids are difficult to characterise because they are not easily subject to traditional probes developed for materials, mainly due to their high vapour pressure and their labile characteristics. The goal of this project is to develop and apply new techniques, mainly cryogenic scanning electron microscopy, to such systems in order to determine their microstructure, and to interpret the resulting micrographs by the theory of contrast formation using image analysis and image processing tools.
3. Permeation in microstructured biomaterials (TA)
Co-guide: Prof. A. Q.. Contractor (Chemistry)
Many natural materials form excellent barriers to permeation, or are very selective in their permeabilities. Common examples are egg shells and egg membranes, which have a delicate balance between permeabilities of oxygen and carbon dioxide. The microstructure of such materials is also complex, and may affect the permeabilities and selectivities. The objective of this project is to study the permeabilities of several such materials and relate them to their microstructure by developing new models. This is expected to have impact on understanding of the process of biomineralization and application to newer industrial processes.
4. Preparation and Characterization of nanodiscs using Surfactants and Multivalent Ions – Electron Microscopic Investigations (TA)
Co-guide: C. Manohar
Prof. GOVARDHANA RAO V.
1. Advanced Oxidation Process for degradation of organic pollutants in industrial wastewater (TA)
Conventional methods for the removal organic pollutants in water merely transfer the pollutants from one phase to the other without destroying them, thus creating a problem of disposal of the transferred material. Advanced oxidation processes this problem. These processes are near ambient temperature and atmospheric pressure processes, which involve the generation of highly reactive radicals, especially hydroxyl radicals in the presence of UV radiation. These highly reactive radicals can degrade organic pollutants, which are hazardous, non-biodegradable and difficult to degrade with chemical oxidants ultimately producing innocuous materials such as carbon dioxide, water etc. These processes show a lot of promise in commercial applications involving degradation of pollutants in water and air. It is proposed to study advanced oxidation process using immobilized TiO2 catalyst on some inert materials such as silica sand, activated carbon in a fluidized bed reactor. The research includes both experimental and theoretical work and is continuation of work done in our laboratory.
2. Studies in compartmented gas fluidized beds (TA)
This belongs to one class of circulating fluidized bed. In several gas-solid reactions, solids are required to be circulated through different reaction zones to carry out reaction with different gaseous reactants. A compartmented fluidized bed reactor with a V-value and a riser can be used to facilitate the solid circulation from one compartment to other compartment and it has been the subject of study in recent times. It is proposed to study solid circulation rates, gas bypass critical bed heights in a compartmented fluidized bed over a wide range of aeration rates in the V-value, riser and in the main bed.
3. Studies on circulating fluidized beds (TA)
In recent years, circulating fluidized bed (CFB) technology is being used for combustion of coal for power generation due to efficient sulfur capture, control of nitrogen oxides, increased carbon burn out and its ability to use wide range of fuels making the technology cost effective. Combustion of low grade fossil fuels and process residues for energy production with strict environmental control, gasification of biomass materials are a few among the successful applications of CFBs? It is proposed to design and operate CFB to study fluid dynamics and heat transfer characteristics. The work involves both theoretical and experimental work.
4. Fluid dynamics and heat transfer in gas-liquid upflow packed beds. (TA)
Several flow regimes exist in co-current gas-liquid upflow and downflow packed bed reactors. Mass and heat transfer rates are significantly affected in these flow regimes. It is proposed to study fluid dynamics and heat transfer in different flow regimes for viscous and non-Newtonian fluids. This is continuation of a doctoral work done earlier. The basic experimental and data acquisition system are available.
Prof. RAVINDRA GUDI
Global Optimization studies in Process Scheduling(TA).
Prof. V.A. JUVEKAR
1. Deposition/ removal of nanoparticles using electric field (PS/TA)
Nanoparticles are electrically charged. This property can be utilized in depositing them on a surface using electric field. By proper application of the field, it is possible to self-organize them on the surface and thereby impart a desired property to the surface. The aim of the present study is to study the dynamics of deposition in a flow through cell made of a transparent, electrically conducting material (Indium-Tin Oxide glass), using video-microscopy and image analysis. The other aim is to develop a mathematically model for the process. The other part the study involves removal of colloidal particles from a surface using electric field. Both these parts of the project are very similar to each other.
2. Studies in preparation/ characterization of Janus Nanoparticles (PS/TA)
Janus particles are those having a duel character. Two halves of the particles have opposite surface characteristics (e.g. one half may be hydrophobic, while the other is hydrophobic). Making these Janus particles is a challenging task. We are developing a novel technique for their preparation using bipolar electrolysis. Aim of this study is to understand this technique and find how to apply it at nano-scale. The study also aims to characterize these particles by study of the rheology of their suspensions and their ability to form and stabilize emulsions.
3. Characterization of Polyelectrolyte adsorption using Quartz Crystal Microbalance (QCM) (PS/TA)
Adsorption of polyelectrolyte plays very important role in surface modification. The important example is protein adsorption on a solid surface. The new generation quartz crystal microbalance is a state of art technique used for measuring the rate of adsorption of macromolecules on a solid surface. A quartz crystal vibrates and the shift in the fundamental frequency of the crystal is related to the amount of the polymer adsorbed. By analyzing the overtones in the frequency it is possible to characterize the adsorbed layer. One can modify the rate of adsorption by application of electric field. Aim of the present study is to study dynamics of polyelectrolyte adsorption in the presence of electric filed using QCM technique. The aim is also to derive the adsorbed layer characteristics through the analysis of QCM data.
NOTE: Funding is available for any one of the above (PS) while the rest are under TA.
Prof. K. C. KHILAR
Nanoparticles find numerous practical uses in the area of healthcare, nonlinear optics, electronics, catalysis and surface coatings, and so on. Our group has been working on the formation of nanoparticles by a particular route known as microemulsion route for about a decade. We have prepared and characterized nanoparticles of silver, silver chloride, platinum, cadmium sulfide, silver sulfide, and titanium oxide using microemulsions of surfactants such as AOT, SDS, and TX-100. We have also prepared core and shell nanoparticles using an expanded version of the same technique.
We have been working on to develop a mathematical model to describe the formation process. A model based on stochastic population balance on micelles seems to be promising.
We propose to carry on our work to develop some nanoparticles based liquid composite products in the area of ultra-hydrophobic surface coatings and sunscreen lotions. The project work will be of both experimental and modeling in nature.
Prof. S. M. MAHAJANI
1. Studies in reactive distillation (TA)
Reactive distillation combines both reaction and distillation. Several benefits such as increase in conversion, reduction in capital and energy cost, increase in selectivity etc. are associated with such an operation. It brings compactness and cost-effectiveness to a chemical plant. However, not all reactions can be conveniently conducted in reactive distillation units. Since reactive distillation involves interaction of reaction, distillation and mixing processes, its applicability for a particular reaction depends on the chemical and physical properties of the system and system components. The work involves evaluation of several potentially important industrial reactions as candidates for reactive distillation, experiments on laboratory scale reactive distillation columns and modelling work to explain the experimental results.
2. Catalysis with zeolites and other solid acids (TA)
Zeolites are well-defined structured crystals of aluminosilicates, which possess a strong potential as catalysts for various reactions associated with hydrocarbons. The applicability of zeolites for vapor phase reactions has been the subject of research for the last two decades. However, their use in liquid phase reactions such as hydration, esterification, etherification etc. has not been as well studied and is the aim of the present work. The work involves experimentation to study the kinetic behaviour of the reaction with various zeolites and other related catalysts, life of catalyst, deactivation, if any, kinetic modelling, etc. The applicability of various other solid acids such as cation exchange resins, solid phosphoric acids, HPA etc. will also be evaluated.
3. Computational Flow Modeling of Multiphase reactors (TA)
Computational flow modeling of multiphase flow systems is still in its preliminary stage. The main hurdle in its way is the inadequacy of the models for various phenomena occurring simultaneously. Bubble-solid, bubble-bubble interactions and their effect on flow filed, effect of dispersed phase on turbulence generation, buoyancy forces in three phase slurry systems, agglomeration of solid particles, etc. are some of these phenomena that need to be modeled systematically for the system under consideration. The work involves development of such models and its coupling with computational flow dynamics (CFD) to simulate the multiphase reactor performance
Prof. ANURAG MEHRA
1. Coalescence behavior of emulsions in shear flows (TA)
Co-guide: Prof. D.V. Khakhar:
With the objective of studying droplet coalescence in surfactant stabilized, oil-in-water emulsions, we have been examining the efficacy of simple shear flows in influencing the coalescence rates. Preliminary investigations in which carefully prepared emulsions were sheared in a couette flow assembly, show that for a fixed surfactant concentration, the hold-up of the emulsified phase and the shear rates have a significant impact on the transient droplet size distributions. The objectives of this study are directed towards unraveling the mechanisms that cause these effects. Much of this work is novel and there are many fundamental, challenging issues here (rates of drainage of the continuous phase film and the consequent film rupture, the different probabilities of coalescence between droplets of similar and dissimilar sizes and so on). In functional terms our objective is to investigate the effect of shearing rates, fractional volumetric hold-ups of the dispersed phase, viscosity ratios of the dispersed/continuous phases and the surfactant types and concentration, on the collision rates and efficiencies.
2. Studies in formation and modeling of food foams and emulsions (PS):
This work will attempt to focus on the basic processes that determine the characteristics of selected food foams (e.g. bread). Even though there is some experimental data available in this regard, rigorous engineering analysis has been applied rarely to these situations. This is a highly multi-disciplinary topic and will involves studying-experimentally and theoretically - the impact of the various factors, such as, the biokinetics of the fermentation, heat and mass transfer, void and structure formation, solidification of the foam etc., on the final characteristics of the product. The work will be essentially computational.
Funding Source: DST; Period of funding: 3 years
Prof. ASHOK MISRA
1. Polymer nanocomposites (TA)
(co-guide: Prof D. V. Khakhar)
Small amounts of nanosized particulates (5%) have been shown to give significant improvements in polymer properties. It is proposed to carry out a study of polymer nanocomposites with clay nanoparticles and carbon nanotubes as reinforcing agents. The processing, structure and properties of the materials will be studied.
Prof. A.S. MOHARIR
1. Studies in reaction-separation systems (TA)
Separation aided by reaction or vice versa is assuming importance. Reactive distillation is a better known example of this class of operations. The concept can be extended to other separations such as adsorption or membrane separation coupled with reaction. The objective of the present work is to develop conceptual design support for a generic reaction-separation task. The work is analytical/computational in nature.
2. Studies in scale-up methodologies (TA)
Conventionally, scale up signifies arriving at design of a system capable of handling larger quantities based on data/experience gained on system prototype handling smaller quantities. The physics underlying the data generating prototype and the actual large scale system is presumably the same. With easy to assemble micro-systems offering a way of generating large amount of data over short periods and consuming less quantities of resources, the scale up assumes a different connotation. The physics of moving, heating, mixing etc. applicable for experimental system could be different than the same for real life system. To develop scale up techniques or techniques which transcend phenomenological boundaries to predict performance of macro systems based on observations on micro systems is the objective of the present work. The work is analytical/computational in nature.
Prof. HEMANT NANAVATI
1. Ab Initio Protein Structure Prediction(TA)
Co-Guide: Prof. Santosh Noronha
Ab Initio protein structure prediction methods (prediction of the 3-D molecular structure using the knowledge of only the amino acid sequence) have exhibited considerable promise in the recent past with several methods, being successful in community-wide experiments (CASP). We have formulated the protein-folding problem as a combinatorial optimization problem where, a variant of Monte Carlo Minimization Algorithm has been employed to achieve the minimum energy configuration. The search for the optimum has been simplified by incorporating the various geometrical constraints of the secondary structural elements using a distance restraint potential function. Additionally, the sample space has been reduced by considering the probability distribution of backbone torsions observed in nature. Simulations carried out on a sequences varying from 29 to 85 amino acids belonging to all classes, have exhibited positive results, and indicate that large proteins can be simulated by this approach in the future in the project offered at the doctoral level.
Filled elastomers or filled rubbers have found extensive uses in industry. The fillers provide advantageous properties over unfilled systems, leading to various applications. One important property that bears investigation is the stress-strain relationship of the elastomers and its relationship to the primary molecular architecture. Experimental data and theoretical developments have been presented earlier. The current investigation aims toward a systematic study of the objective relationship between molecular structure and stress-elongation relationship. The approach involves performing rotational isomeric states - monte-carlo (RIS-MC) simulations of entire chains, in addition to theoretical development using tools such as Mathematica. The developed models will be validated using literature data as well from experiments performed during the research.
Prof. SANTOSH NORONHA
Analysis of Protein structures. (TA)
The work involves analysis of aligned protein structures using geometric metrics and force-field dependent scoring fields. The work will require extensive coding (C/Perl) and will require learning pattern classification techniques.
2. Multivariate analysis of genetic networks. (TA)
(Co-guide Prof. R. Gudi)
This project involves the systematic identification of genetic networks transcript information, using various pattern classification techniques. Genetic networks will be simulated in Matlab and various classification techniques compared. The methodology developed will be tested on microarray datasets.
Prof. SHARAD BHARTIYA
Control Characterization of genetic regulatory networks
Co-guide: KV Venkatesh
Genetic networks exist to regulate the protein expression in a cell to attain a specific phenotypic state. These networks comprise of feedback loops and unique control structures, which have been elucidated in the recent past. These structures can be analyzed using theories of modern and classical feedback control. The project involves modeling such
networks to evaluate the underlying control elements. Such unique natural genetic controllers are envisaged to be useful in designing novel industrial control schemes.
2. Process Modeling, Optimization and Control of Wheat Straw Pulping in
Continous Pandia Digester (PS)
The small and medium scale Indian paper industry widely uses non-wood fibres for pulping. Wheat-straw, rice straw, bagasses among others are commonly available feedstock. However, much of the modeling and control literature has focussed on wood based pulps. This work will attempt to address the existing gap by focussing on developing a kinetic model for
wheat based pulps and subsequently using it to develop a fundamental model for Pandia digesters. Following this, we will develop a state-estimation, optimization and model based control strategies for its operation.
Funding agency: Ministry of Commerce Period of funding: 2 years(extendable)
Prof. T.S. RAGHUNATHAN
1. Modelling studies in heterogeneous polyaddition reaction systems(TA)
The work envisaged includes analysis of existing experimental data on emulsion, homo, and coploymerizations of industrial monomers such as styrene, acrylonitrile, butadiene etc. It is proposed to arrive at a sound predictive model capable of providing satisfactory design information for the design of batch/semi-batch/continuous reactors.
Prof. SANDIP ROY
Prof. H.S. SHANKAR
1. Flow and reaction in porous media (TA)
This is a continuation of work on soil biotechnology already in public domain. In this work studies on media, flow field, additives are proposed so as to improve biological reaction rates and specificity. The work will involve theory (modeling and computational), laboratory and commercial scale plant investigations with reference to drinking water, water bodies and wastewater of community and industry.
2. Modeling Studies in rate processes. (TA)
Chemical reaction involving high temperature gas-solid non-catalytic systems are many. Lime calcination, iron smelting are common examples. In small scale many of these processes utilise batch operation due to economics. In view of frequent charging and discharging the uniformity of packing in the bed is poor and consequently product yield and quality suffers. Since temperatures are high, chemical reaction is often not the rate-limiting step. By introducing pulsed operation (pressure pulsation, flow pulsation etc.) it may be possible to break the boundary layer and bring about substantial improvements in the overall rate process and quality of product. The fact that several life processes use pulsed operation for oxygen supply is an object example before us.
In this work effect of pulsing on the rates of transfer in simple model system will first be investigated. This experience will be used to deal with commercially important processes. The work is expected to involve substantial modelling, computational and high temperature experimental validation both in laboratory and industry.
3. Nitrates in life Processes: (TA)
Co-guide: Prof. P. Wangikar
Nitrogen is an essential element of life processes being present in protein, nucleic acids and so on. Several organisms are able to derive their nitrogen from nitrates; often such organisms are pathogenic and cause diseases in human and animals. Denitrifying bacteria are such organisms and mycobacteria are such examples and are known to cause tetanus, TB etc.. And more recently it has been observed that several disease conditions lead to production of nitrate which appears in the excretions such as urine etc. It thus emerges that nitrates are both a cause and consequence of pathological condition of host- so to say.
In this work it is proposed to understand the genome engaged in the metabolism of nitrates and nitrate release. This is the first phase of a program of study towards understanding nitrates and their role in causation of disease. The work may involve considerable amount of computational biology.
Prof. A.K. SURESH
in Solid phase reactions: (TA)
Many reactions in the cement and ceramic industry involve reactions which take place in the solid phase. Experimental and theoretical methods for investigating such reactions form the theme here. While shrinking core methods have been used in analysing such reactions, the assumptions underlying such treatments are only valid under a very restricted set of circumstances and new types of models seem to be indicated. Experimental methods of investigating kinetics of such reactions have normally involved thermal analysis, and recent studies have indicated a number of shortcomings in the interpretation of results from such analyses. The theoretical modeling envisaged would involve modelling and associated analytical/numerical work, and the experimental work would involve thermogravimmetry, DSC etc, and quantitative analyses using XRD.
Prof. K.V. VENKATESH
Regulatory analysis of the cell
Co-Guide: Sharad Bhartiya
Living systems are replete with complex networks. One such network is the cell cycle regulation by P53. There are mutiple control points yielding precise regulation of the cell cycle. Failures in such a regulation results in desease state such as cancer. A system level analysis of the network is proposed. The study is supposed to give insights into the
design of such natural networks and the purpose that they are designed for.
Prof. P. WANGIKAR
Synthesis and implementation of operating strategies for rifamycin B fed-batch fermentation.(TA)
Co-guide: Sharad Bhartiya.
Abstract: Antibiotics such as rifamycin B are typically produced through fed-batch fermentation process using a complex medium. Our group has been involved in development of a first-principles dynamic model for production of rifamycin B. The increased competition in the fermentation industry will force the manufacturer to use advanced model-based strategies for fermentation optimization, monitoring and control. In the proposed work, it is envisaged that the existing model for rifamycin B fermentation will be used in the following: (i) synthesis of optimal feeding strategies; (ii) model based inferential measurements; (iii) model based predictive control of fermentor; (iv) model based fault detection and diagnosis. The work includes experimental validation of the above elements on a laboratory scale fermentor. The student is expected to have a chemical engineering background with exposure to process control. Prior experience with operating a fermentor is not necessary as training will be provided for the same.
1. Air Pollution in Indian Megacities: Impact of Technology Alternatives in the Power and Transport Sectors (TA)
It is well established that concentrations of several pollutants, especially air particles or atmospheric aerosols, exceed safe levels in Indian “megacities,” with serious health implications. There is also recent interest in the potential interaction of pollution particles with regional and global climate and in linking “megacity” pollution to regional climate. An important step in devising air pollution control strategies is the understanding the contribution of various sources to given pollutants. We carry out air quality assessment using atmospheric modeling, supported by robust emissions databases, developed by our group, and model-validation exercises using measurements from short-term campaigns and continuous networks. A combination of experiments and computer simulations from atmospheric models is used to deduce sources, atmospheric transport and effects of air pollutants. What-if questions related to technology alternatives (e.g. CNG vs low-sulphur diesel, coal- vs gas-fired power generation) will be addressed using chemical information on specific source emissions, especially from the power and transport sectors. In addition, we have an ongoing activity in developing computationally efficient atmospheric models. This research is supported through grants from ISRO-GBP and MHRD, enriched by our national and international collaborations and participation in international studies like the Indian Ocean Experiment and Atmospheric Brown Cloud project. This research is of great value to urban and national air quality planning and international development/policy agencies like World Bank / Asian Development Bank.
2. Advanced aerosol drug delivery (with Prof. Jayesh Bellare) (TA)
Successful delivery of drug aerosols to the lung requires consideration of the powder production process, drug formulation and inhaler device. We have developed laboratory techniques for nano-particle characterization using laser-based particle sizing/counting, aerodynamic particle sizing and electron microscopy. We aim to apply these methods to developing “designer” micro-encapsulated drugs by optimising the size distribution, density, morphology and surface properties of carrier particles. These factors govern their aerodynamic deposition characteristics, which will be measured and optimised for efficient pulmonary deposition, estimated using lung-deposition models. New generation inhalers must reduce or completely decouple the influence of airflow on the aerosol generation. We propose the development of inhalers, particularly propellant driven metered dose inhalers, with attention to drug formulation, metering and device technology. This exciting new field has tremendous industrial potential, to service India's large internal market for advanced pharmaceutical therapies.
3. Modelling atmospheric transport and climate change from aerosol emissions from biomass burning (TA)
The field of atmospheric aerosol research draws on Chemical Engineering fundamentals of multi-phase reactions, fluid/particle mechanics and transport. Aerosols, or nano-particles of the atmosphere, interact with radiation and modify climate, including atmospheric temperature and the monsoons. The emerging role of black carbon, especially that from biomass burning, must be understood through modelling the interplay between chemical composition of the multi-component particles and their optical properties. Such investigations feed into large scale general circulation models for prediction of climate change. This research is related to an ongoing Indo-French project "Aerosols and the Indian Monsoons." The topic would suit students with an aptitude for computational work and a potential interest in a research / academic career.
Design and Simulation of a Low NOx burner (TA)
Co-Guide: Anuraddha Ganesh (Energy Systems)
A natural gas burner with acceptably low emissions of NOx is to be designed and optimised. Experimental part of the project includes gas analysis for NO and other relevant species, while the modelling/simulations work involves the use of CFD software, coupled with detailed surface reaction mechanisms.
2. Reduction of Chemical Reaction Mechanisms for Application to High Speed
Aim of this project is to develop reduced chemical reaction mechanisms for complex hydrocarbon fuels. The reduced sets are to be small enough for use in detailed simulations of high speed flows (using CFD). Work is entirely mathematical modeling/simulations.
for 2 years by DRDL, Hyderabad at Rs. 10000 p.m. + HRA
Would like to take 1 student.
1. On-line Fault Diagnosis and Advanced Control Bio-reactors (TA)
(Co-Guide: Prof. Santosh Noronha)
This topic involves development of (a) model based adaptive and predictive control and (b) on-line fault diagnosis algorithms and their applications to control bio-reactors. The algorithms developed will be tested using simulation studies and computer controlled experimental setups.
2. Nonlinear Predictive Control of Distributed Parameter Systems (TA)
This topic involves development of (a) data driven and gray box models (b) nonlinear state estimators and (c) model based adaptive and predictive control of distributed parameter systems. The algorithms developed will be tested using simulation studies and computer controlled experimental setups (such as packed bed column, reactive distillation column).
Predictive control relevant closed loop model identification (TA)
(Co-guide: Prof. R. D. Gudi)
The area of re-identification of dynamic models for predictive control in closed loop is receiving considerable attention in last few years. This project is aimed at developing fast rate dynamic models suitable for model predictive control from closed loop data. The work will involve simulation as well as experimental studies.
1. Depth Profiling of
Multilayered Coatings (TA)
Photographic films, adhesives, some optical coatings and novel biodegradable polymer stents (used as local drug delivery devices) are all multilayered with each layer serving a definite function. These coatings can be prepared sequentially or simultaneously from a solution made by dissolving a polymer in solvent(s). In the former, the solution cast on a substrate is dried and then another layer is cast and dried. This process is repeated till all layers are laid. In the latter, all the layers are cast and then dried at the same time. This project investigates drying behaviour of multilayered coatings laid sequentially and simultaneously-through theory and experiments-to understand how solvent distributes among different layers upon drying and how drying conditions determine the distribution. One of the aims is to reduce the solvent levels in the coatings below specifications specially when used as stents. The distribution of solvent can be measured by depth profiling the drying coating. This will be conducted with Confocal Raman Microscope. Theoretical work, to gain insight into the drying behaviour and to guide experiments, involves solving a set of coupled non-linear partial differential equations.
This is collaborative project with a research group in Nanyang Technological University (NTU) in Singapore. Though the project would investigate drying of several coatings, the focus will be on drying of biodegradable multilayered coatings used as stents.
Prof. VINAY PRASAD
Multiscale modeling and control of crystallization processes
(Co-guide: Sharad Bhartiya)
This project aims to study processes involving crystallization from solution and from the vapor phase. In each case, the project will involve building models at different time and length scales. For example, nucleation and growth will be described at the micro- and nano-
scale using molecular dynamics models, and continuum models (using population balances and compartmental modeling) will be used to describe the evolution of shape and size of crystals at larger length and time scales, and these models will be linked to form the multiscale models. The final aim is to predict and control the shape, size and properties of crystals grown in this manner. The project involves modeling and simulation and has a strong numerical component. The ideal candidate will have a strong inclination towards molecular and continuum modeling, mathematical techniques and numerical methods.
2. Multiscale analysis of stochastic biological systems (TA)
Stochasticity is a well-known feature of biological intracellular signal networks. Traditional differential equation modeling tools are often inadequate for the study of these systems due to the large separation of time scales and the wide range of population sizes of signaling species
in a cell. Stochastic simulations are often computationally too intense for most of these biological systems. The stochastic simulation algorithm, the chemical Langevin equation and the binomial tau-leap method have been used in the representation and analysis of bioreaction
networks such as the MAP kinase cascade. This project involves the use and development of stochastic analysis tools to make the study of these systems tractable, and to understand the role of fluctuations and nonlinear behavior in these networks. The project will also involve the development of model reduction methods for multiscale stochastic systems. The ideal candidate will have a strong mathematical and numerical background.
Prof. MAHESH S. TIRUMKUDULU
Liquid sheet break-up in the presence of an acoustic field (PS)
(Co-guide: Prof Ananthakrishnan N, Aerospace Eng., IIT-B)
The objective of this study is to determine the nature of the interaction between the acoustic oscillations set up in the combustion chamber (such as that in a liquid rocket engine) and the fuel injection process; in particular, the influence of acoustic waves in the chamber on the atomization/break-up of a liquid sheet formed by impinging jets of liquid fuel injected into the chamber. We plan to study the effect of acoustic frequency on the break-up of a liquid sheet formed from the impingement of two similar jets over a range of jet speeds (laminar and turbulent regime) and impingement angles. Acoustic forcing will be provided externally via a high amplitude acoustic source. The goal is to provide a theoretical framework to explain the observed results.
Funding agency: ISRO Funding: Rs. 10,000 pm for 2 years (extendable)
Prof. ROCHISH THAOKAR
1. Electrohydrodynamics and Electrokinetics under AC
Electrohydrodynamics and electrokinetics involve interaction of fluid charges with the applied electric field and their interplay can lead to interesting phenomenon. These have extensive applications in industrial processes involving lithography, microfluidics and systems involving colloidal dispersions. The two fields however differ in one important aspect.. The bulk fluids in electrohydrodynamics are neutral while those in electrokinetic systems are charged. This means that the electric fields affecting the two processes can be different by an order of magnitude. Although these phenomenon are widely studied under application of DC fields, much needs to be understood when they are subjected to alternating electric fields. AC fields are known to affect as well as produce novel effects in these systems. AC electrokinetics is widely used in nano-patterning of colloidal dispersions on substrate electrodes and is known to exhibit dielectrophoresis and electrorotation. The project would involve analytical (Floquet theory), numerical (Boundary element method) as well as experiments (Electrokinetic) to study instabilities and flows in these systems. In Electrohydrodynamics it is planned to study drop deformation under AC fields on substrates. In the electrokinetic part, electro-osmotic flows under AC fields would be studied. The known instabilities in electrohydrodynamics and the new observations would be used to conceptualize new microfluidic devices.
2. Instability studies in Foam Flows: (Co-Guide: Prof Kartic Khilar) (TA)
Foams are ubiquitous in everyday life. Simple examples are sea foams and wood, sea sponges, Polyurethane foams, whipped cream and chocolate mousse, shaving foam and hair mousse, oven cleaner and limescale remover, fire extinguishers. They are industrially important. As nuisance (mostly in chemical and petroleum industry) and as an important type of gas liquid contact, owing to their high interfacial area (foam flotation and protein separation, well as enhanced oil recovery. Liquid foam is a concentrated dispersion of a gas in liquid where the volume fraction of the dispersed phase is as high as 90 percent. Made up of liquid films which join to form a plateau border, foams are perpetually out of equilibrium and their structure spontaneously evolves via three mechanisms : drainage, bubble coalescence and gas diffusion. They are viscoelastic solids when they are subjected to sufficiently small stresses while at high applied stress they flow as viscous non Newtonian liquids. Convective instabilities were discovered in foams in cylindrical geometries, where the aqueous foams contained in a cylinder, are forced drained (flooded) from the top of the column using surfactant solution. The instability sets up convective rolls in the column with high liquid fraction foam coming down from one side and the dry foam moving up on the other side. The bubble size in these systems was large. Similar instabilities were also observed for foams of very small bubble size and is qualitatively different than the previous instability, and shows large scale swirls. Both these instabilities are found to occur in static foams which are forced drained from the top. In works on liquid holdup in a semibatch foam, a marked recirculation of bubbles around the walls in a semibatch foam in cylindrical container have been observed. It was noted that bubbles travel down the wall while the core is mostly occupied by upward traveling foam. This aspect was not probed in much details until
recently when recirculation regime in vertical pipe flows was observed. It would be interesting to study foam flows in 2 D columns since it gives better visulisation. We intend to study extensively the different flow regimes and the possibility of a recirculation instability in foams using a 2D geometry. We plan to carry out the modeling efforts in two directions. There have been simulations on 2D foam columns explaining several different phenomenon in aqueous foam flows. We plan to Implement these simulation strategies to explain the instabilities. Secondly, we intend to derive phenomenological equation for these systems using the existing rheological models and carry out linear stability analysis for such systems to predict the experimentally observed instabilities. Other problems which would be addressed are: Rheology of Semi batch foams, possibility of Brazil Nut effect in foams, and two problems to substantiate a viscoelastic model: Foam flows on inclined plates and Foam flows over bluff bodies.