Simant Upreti - Academia.edu (original) (raw)
Papers by Simant Upreti
Encyclopedia of Chemical Processing (Print Version), 2005
Macromolecular Theory and Simulations, 2005
Macromolecular Theory and Simulations, 2010
The effect of nematic droplet shape, elastic constant ratio of liquid crystals, and external fiel... more The effect of nematic droplet shape, elastic constant ratio of liquid crystals, and external field strength on the performance of PDLC films is examined. The finite-difference method is used to model a single droplet with external field applied parallel to the droplet axis of symmetry. Genetic algorithm is employed to determine the optimal (i) aspect ratio, (ii) elastic constant ratio, and (iii) external field strength, which minimize the response and relaxation times for the droplet reorientation as well as the energy requirement.
Journal of Process Control, 2008
This paper develops a method for minimum variance control of proportional–integral (PI) controlle... more This paper develops a method for minimum variance control of proportional–integral (PI) controllers in the presence of input stochastic noise, the abatement of which is an important issue in many control systems. The underlying objective is to mitigate the effect of input noise in the process output, subject to process inequality constraints. For this purpose, a hybrid genetic algorithm is
Journal of Petroleum Science and Engineering, 2006
In this work, a mathematical model is developed and simulated to determine gas dispersion along w... more In this work, a mathematical model is developed and simulated to determine gas dispersion along with solubility during the vapor extraction (Vapex) of live oil from a laboratory scale physical model. The physical model is a rectangular block of homogenous porous medium saturated with heavy oil and bitumen. At a given temperature and pressure, the block is initially exposed on its side to a solvent gas, which diffuses into the medium and gets absorbed. The absorption of gas reduces the viscosity of heavy oil and bitumen causing it to drain under gravity. The low-viscosity "live oil" is produced at the bottom of the porous block. The production of live oil with time is accompanied by the shrinkage of oil in the block as well as its increased exposure to gas from top. These phenomena of Vapex are described by the mathematical model, which is used to calculate live oil production with various values of gas solubility and dispersion. Their optimal values are determined for the vapor extraction of Cold Lake bitumen with butane by matching calculated live oil production with its experimental values published earlier.
Journal of Experimental Nanoscience, 2010
... Small angle neutron scattering and photoluminescence property of wet chemistry process synthe... more ... Small angle neutron scattering and photoluminescence property of wet chemistry process synthesised ZnO nanoparticles NC Dasa*, S. Upretib and PE Sokola ... 120124. [9] M. Muhammed, Chemical methods for the synthesis of nanophase materials, Analysis 24 (1996), pp. ...
Journal of Applied Polymer Science, 2006
In this paper, the optimal policies for bulk polymerization of n-butyl methacrylate (BMA) are det... more In this paper, the optimal policies for bulk polymerization of n-butyl methacrylate (BMA) are determined in a nonisothermal batch reactor. Four objectives are realized for BMA polymerization based on a detailed process model. The objectives are: (i) maximization of monomer conversion in a specified operation time, (ii) minimization of operation time for a specified, final monomer conversion, (iii) maximization of monomer conversion for a specified, final number average polymer molecular weight, and (iv) maximization of monomer conversion for a specified, final weight average polymer molecular weight. For each objective, the optimal temperature policy of heat-exchange fluid inside reactor jacket is determined. The temperature of the heat-exchange fluid is considered as a function of a specified variable. Necessary equations are provided to suitably transform the process model in terms of a specified variable other than time, and to evaluate the elements of Jacobian to help in the accurate solution of the process model. A genetic algorithm-based optimal control method is applied to realize the objectives. The resulting optimal policies of this application reveal considerable improvements in the batch production of poly (BMA).
Journal of Applied Polymer Science, 1996
An ultrathin joint in a poly(methy1 methacrylate) (PMMA) beam was introduced by joining the two p... more An ultrathin joint in a poly(methy1 methacrylate) (PMMA) beam was introduced by joining the two pieces using 1,2-dichloroethane. The viscoelastic property of the interfacial region was varied using dioctylphthalate (DOP) plasticizer and flexural waves in the beam were generated by impacting the beam with a small steel ball as well as with a calibrated experimental impact hammer. The acceleration vs. time data of a given point on a beam were used to optimally separate the wave emanating from the joint and were shown to correlate
Journal of Applied Polymer Science, 2011
In this work, we experimentally determine the concentration-dependent diffusivity of carbon dioxi... more In this work, we experimentally determine the concentration-dependent diffusivity of carbon dioxide in low-density poly(ethylene) (LDPE). For this purpose, experiments are carried out to obtain pressure-decay data for isothermal diffusion of the gas in the polymer. Based on a detailed mass transfer model, variational calculus is used to establish the conditions necessary to yield the concentration-dependent diffusivity that enables the modelpredicted mass of absorbed gas in polymer to match with the experimental counterpart. A computational algorithm is implemented to solve the model and the conditions and obtain the diffusivities. Determined at 120 and 130 C for four different pressures in the range 0.352 to 1.232 MPa, the diffusivities are strong unimodal functions of gas concentration in polymer and of the order 10 À9 m 2 s À1 . Mathematical correlations are developed to calculate the diffusivity at a given temperature, pressure, and gas concentration.
International Journal of Hydrogen Energy, 2013
Industrial & Engineering Chemistry Research, 2007
... Using Computational Fluid Dynamics Modeling and Ultrasonic Doppler Velocimetry To Study Pulp ... more ... Using Computational Fluid Dynamics Modeling and Ultrasonic Doppler Velocimetry To Study Pulp Suspension Mixing. ... Computational fluid dynamics (CFD) is a useful tool for studying fluid flows, including those of mixing systems. ...
Industrial & Engineering Chemistry Research, 2008
... Salwan Saeed, Farhad Ein-Mozaffari* and Simant R. Upreti. Department of Chemical Engineering,... more ... Salwan Saeed, Farhad Ein-Mozaffari* and Simant R. Upreti. Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada. Ind. Eng. Chem. Res. , 2008, 47 (19), pp 74657475. ...
Industrial & Engineering Chemistry Research, 2000
A new technique is developed to measure the diffusivity of gas in bitumen as a function of compos... more A new technique is developed to measure the diffusivity of gas in bitumen as a function of composition. Results are presented for a carbon dioxide-bitumen system, which is of considerable industrial relevance. The technique employs transient pressure data obtained from a nonintrusive pressure decay experiment at constant temperature and volume. The underlying theory is presented along with a computational algorithm to calculate diffusivity. Using experimental pressure decay data in the range 25-90°C at 4 MPa, the diffusivity of carbon dioxide in bitumen is calculated. The results are compared with the limited data available in the literature. The approach is straightforward and can be easily applied to other nonvolatile liquid systems. .
European Polymer Journal, 2005
In this work, we determine the optimal control for free-radical methyl methacrylate polymerizatio... more In this work, we determine the optimal control for free-radical methyl methacrylate polymerization using a bifunctional initiator in a non-isothermal batch reactor. A detailed unsteady-state model of the process is employed. Four different optimal control objectives are realized, each of which optimizes a given variable simultaneously with the specification of another. The first two objectives involve the maximization of monomer conversion in a specified operation time, and the minimization of operation time for a specified, final monomer conversion. The last two objectives involve the maximization of monomer conversion for specified, final number and weight average polymer molecular weights. The temperature of heat-exchange fluid inside reactor jacket is considered as a control function of an independent variable. To meet the specification of an optimization variable other than time, the differential model of batch process is derived in the range of specified variable. Equations are provided for Jacobian evaluations to help in the accurate solution of process model. A genetic algorithms-based optimal control method is applied to realize the four optimal control objectives. The results show that optimal control can significantly enhance the performance of the batch polymerization process.
Drying Technology, 2006
In this work, the optimal control policies of radiant temperature versus dryer length are determi... more In this work, the optimal control policies of radiant temperature versus dryer length are determined for the continuous, steady-state operation of infrared dryers. The optimal control objective is to minimize the product humidity subject to a mathematical model of infrared dryers as well as a set of process inequality constraints. A robust optimal control method based on genetic algorithms is
Computers & Chemical Engineering, 1996
... San Mateo: Morgan Kaufmann ( 1991 ). Deb K., Genetic algorithms for engineering design optimi... more ... San Mateo: Morgan Kaufmann ( 1991 ). Deb K., Genetic algorithms for engineering design optimiza tion. ... (D.Sc. thesis). MIT (1964). Forrest S. (Ed.), Proceedings of the fifth international con ference on genetic algorithms. San Mateo, CA: Morgan Kaufmann (1993). ...
Chemical Engineering Science, 2010
Chemical Engineering Science, 2004
The temperature at the surface of a human body is strongly related to heat generation in underlyi... more The temperature at the surface of a human body is strongly related to heat generation in underlying tissue, and its perfusion by blood. The phenomena of heat generation and dissipation unfold the thermo-regulatory control of a human body. Excursions of body temperatures from "normal" have long been considered as evidence of ill health or abnormal physiological states. In this paper, a noninvasive technique is presented to determine the peripheral rates of heat generation and blood flow in a human limb from its recorded skin surface temperature. The technique involves an analysis based on calculus-of-variation, and features the well-known circadian cycle of mammalian body temperature. The method can readily be adapted to different body parts given appropriate heat transfer models. Further, the method may confirm or contribute to greater reliability of medical diagnosis of individuals for whom recorded skin surface temperatures are available. The technique is demonstrated for a set of skin surface temperature data.
Encyclopedia of Chemical Processing (Print Version), 2005
Macromolecular Theory and Simulations, 2005
Macromolecular Theory and Simulations, 2010
The effect of nematic droplet shape, elastic constant ratio of liquid crystals, and external fiel... more The effect of nematic droplet shape, elastic constant ratio of liquid crystals, and external field strength on the performance of PDLC films is examined. The finite-difference method is used to model a single droplet with external field applied parallel to the droplet axis of symmetry. Genetic algorithm is employed to determine the optimal (i) aspect ratio, (ii) elastic constant ratio, and (iii) external field strength, which minimize the response and relaxation times for the droplet reorientation as well as the energy requirement.
Journal of Process Control, 2008
This paper develops a method for minimum variance control of proportional–integral (PI) controlle... more This paper develops a method for minimum variance control of proportional–integral (PI) controllers in the presence of input stochastic noise, the abatement of which is an important issue in many control systems. The underlying objective is to mitigate the effect of input noise in the process output, subject to process inequality constraints. For this purpose, a hybrid genetic algorithm is
Journal of Petroleum Science and Engineering, 2006
In this work, a mathematical model is developed and simulated to determine gas dispersion along w... more In this work, a mathematical model is developed and simulated to determine gas dispersion along with solubility during the vapor extraction (Vapex) of live oil from a laboratory scale physical model. The physical model is a rectangular block of homogenous porous medium saturated with heavy oil and bitumen. At a given temperature and pressure, the block is initially exposed on its side to a solvent gas, which diffuses into the medium and gets absorbed. The absorption of gas reduces the viscosity of heavy oil and bitumen causing it to drain under gravity. The low-viscosity "live oil" is produced at the bottom of the porous block. The production of live oil with time is accompanied by the shrinkage of oil in the block as well as its increased exposure to gas from top. These phenomena of Vapex are described by the mathematical model, which is used to calculate live oil production with various values of gas solubility and dispersion. Their optimal values are determined for the vapor extraction of Cold Lake bitumen with butane by matching calculated live oil production with its experimental values published earlier.
Journal of Experimental Nanoscience, 2010
... Small angle neutron scattering and photoluminescence property of wet chemistry process synthe... more ... Small angle neutron scattering and photoluminescence property of wet chemistry process synthesised ZnO nanoparticles NC Dasa*, S. Upretib and PE Sokola ... 120124. [9] M. Muhammed, Chemical methods for the synthesis of nanophase materials, Analysis 24 (1996), pp. ...
Journal of Applied Polymer Science, 2006
In this paper, the optimal policies for bulk polymerization of n-butyl methacrylate (BMA) are det... more In this paper, the optimal policies for bulk polymerization of n-butyl methacrylate (BMA) are determined in a nonisothermal batch reactor. Four objectives are realized for BMA polymerization based on a detailed process model. The objectives are: (i) maximization of monomer conversion in a specified operation time, (ii) minimization of operation time for a specified, final monomer conversion, (iii) maximization of monomer conversion for a specified, final number average polymer molecular weight, and (iv) maximization of monomer conversion for a specified, final weight average polymer molecular weight. For each objective, the optimal temperature policy of heat-exchange fluid inside reactor jacket is determined. The temperature of the heat-exchange fluid is considered as a function of a specified variable. Necessary equations are provided to suitably transform the process model in terms of a specified variable other than time, and to evaluate the elements of Jacobian to help in the accurate solution of the process model. A genetic algorithm-based optimal control method is applied to realize the objectives. The resulting optimal policies of this application reveal considerable improvements in the batch production of poly (BMA).
Journal of Applied Polymer Science, 1996
An ultrathin joint in a poly(methy1 methacrylate) (PMMA) beam was introduced by joining the two p... more An ultrathin joint in a poly(methy1 methacrylate) (PMMA) beam was introduced by joining the two pieces using 1,2-dichloroethane. The viscoelastic property of the interfacial region was varied using dioctylphthalate (DOP) plasticizer and flexural waves in the beam were generated by impacting the beam with a small steel ball as well as with a calibrated experimental impact hammer. The acceleration vs. time data of a given point on a beam were used to optimally separate the wave emanating from the joint and were shown to correlate
Journal of Applied Polymer Science, 2011
In this work, we experimentally determine the concentration-dependent diffusivity of carbon dioxi... more In this work, we experimentally determine the concentration-dependent diffusivity of carbon dioxide in low-density poly(ethylene) (LDPE). For this purpose, experiments are carried out to obtain pressure-decay data for isothermal diffusion of the gas in the polymer. Based on a detailed mass transfer model, variational calculus is used to establish the conditions necessary to yield the concentration-dependent diffusivity that enables the modelpredicted mass of absorbed gas in polymer to match with the experimental counterpart. A computational algorithm is implemented to solve the model and the conditions and obtain the diffusivities. Determined at 120 and 130 C for four different pressures in the range 0.352 to 1.232 MPa, the diffusivities are strong unimodal functions of gas concentration in polymer and of the order 10 À9 m 2 s À1 . Mathematical correlations are developed to calculate the diffusivity at a given temperature, pressure, and gas concentration.
International Journal of Hydrogen Energy, 2013
Industrial & Engineering Chemistry Research, 2007
... Using Computational Fluid Dynamics Modeling and Ultrasonic Doppler Velocimetry To Study Pulp ... more ... Using Computational Fluid Dynamics Modeling and Ultrasonic Doppler Velocimetry To Study Pulp Suspension Mixing. ... Computational fluid dynamics (CFD) is a useful tool for studying fluid flows, including those of mixing systems. ...
Industrial & Engineering Chemistry Research, 2008
... Salwan Saeed, Farhad Ein-Mozaffari* and Simant R. Upreti. Department of Chemical Engineering,... more ... Salwan Saeed, Farhad Ein-Mozaffari* and Simant R. Upreti. Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada. Ind. Eng. Chem. Res. , 2008, 47 (19), pp 74657475. ...
Industrial & Engineering Chemistry Research, 2000
A new technique is developed to measure the diffusivity of gas in bitumen as a function of compos... more A new technique is developed to measure the diffusivity of gas in bitumen as a function of composition. Results are presented for a carbon dioxide-bitumen system, which is of considerable industrial relevance. The technique employs transient pressure data obtained from a nonintrusive pressure decay experiment at constant temperature and volume. The underlying theory is presented along with a computational algorithm to calculate diffusivity. Using experimental pressure decay data in the range 25-90°C at 4 MPa, the diffusivity of carbon dioxide in bitumen is calculated. The results are compared with the limited data available in the literature. The approach is straightforward and can be easily applied to other nonvolatile liquid systems. .
European Polymer Journal, 2005
In this work, we determine the optimal control for free-radical methyl methacrylate polymerizatio... more In this work, we determine the optimal control for free-radical methyl methacrylate polymerization using a bifunctional initiator in a non-isothermal batch reactor. A detailed unsteady-state model of the process is employed. Four different optimal control objectives are realized, each of which optimizes a given variable simultaneously with the specification of another. The first two objectives involve the maximization of monomer conversion in a specified operation time, and the minimization of operation time for a specified, final monomer conversion. The last two objectives involve the maximization of monomer conversion for specified, final number and weight average polymer molecular weights. The temperature of heat-exchange fluid inside reactor jacket is considered as a control function of an independent variable. To meet the specification of an optimization variable other than time, the differential model of batch process is derived in the range of specified variable. Equations are provided for Jacobian evaluations to help in the accurate solution of process model. A genetic algorithms-based optimal control method is applied to realize the four optimal control objectives. The results show that optimal control can significantly enhance the performance of the batch polymerization process.
Drying Technology, 2006
In this work, the optimal control policies of radiant temperature versus dryer length are determi... more In this work, the optimal control policies of radiant temperature versus dryer length are determined for the continuous, steady-state operation of infrared dryers. The optimal control objective is to minimize the product humidity subject to a mathematical model of infrared dryers as well as a set of process inequality constraints. A robust optimal control method based on genetic algorithms is
Computers & Chemical Engineering, 1996
... San Mateo: Morgan Kaufmann ( 1991 ). Deb K., Genetic algorithms for engineering design optimi... more ... San Mateo: Morgan Kaufmann ( 1991 ). Deb K., Genetic algorithms for engineering design optimiza tion. ... (D.Sc. thesis). MIT (1964). Forrest S. (Ed.), Proceedings of the fifth international con ference on genetic algorithms. San Mateo, CA: Morgan Kaufmann (1993). ...
Chemical Engineering Science, 2010
Chemical Engineering Science, 2004
The temperature at the surface of a human body is strongly related to heat generation in underlyi... more The temperature at the surface of a human body is strongly related to heat generation in underlying tissue, and its perfusion by blood. The phenomena of heat generation and dissipation unfold the thermo-regulatory control of a human body. Excursions of body temperatures from "normal" have long been considered as evidence of ill health or abnormal physiological states. In this paper, a noninvasive technique is presented to determine the peripheral rates of heat generation and blood flow in a human limb from its recorded skin surface temperature. The technique involves an analysis based on calculus-of-variation, and features the well-known circadian cycle of mammalian body temperature. The method can readily be adapted to different body parts given appropriate heat transfer models. Further, the method may confirm or contribute to greater reliability of medical diagnosis of individuals for whom recorded skin surface temperatures are available. The technique is demonstrated for a set of skin surface temperature data.