Phone: 509-335-7989 Address: Prashanta Dutta
Associate Professor
Mechanical and Materials Engineering
Washington State University
Pullman, WA 99164-2920, USA
On-chip isoelectric focusing (IEF) has been performed in both straight and dog-leg microchannels.... more On-chip isoelectric focusing (IEF) has been performed in both straight and dog-leg microchannels. Three-dimensional microfluidic chips were fabricated on poly di-methyl-siloxane (PDMS) using soft lithography and multilayer bonding techniques. Plasma oxidized PDMS channel surfaces were dynamically coated with methyl cellulose to discourage electroosmotic flow during separation and purification processes. In a straight microchannel, IEF was completed within 5 minutes at an applied electric field strength of 50 V/cm using ...
This paper describes the preconcentration of the biomarker cardiac troponin I (cTnI) and a fluore... more This paper describes the preconcentration of the biomarker cardiac troponin I (cTnI) and a fluorescent protein (R-phycoerythrin) using cationic isotachophoresis (ITP) in a 3.9 cm long poly (methyl methacrylate)(PMMA) microfluidic chip. The microfluidic chip includes a channel with a 5Â reduction in depth and a 10Â reduction in width. Thus, the overall cross-sectional area decreases by 50Â from inlet (anode) to outlet (cathode).
Abstract Recent experimental studies show that electrokinetic phenomena such as electroosmosis an... more Abstract Recent experimental studies show that electrokinetic phenomena such as electroosmosis and electrophoresis can be used to separate nanoparticles on the basis of their size and charge using nanopore-based devices. However, the efficient separation through a nanopore depends on a number of factors such as externally applied voltage, size and charge density of particle, size and charge density of membrane pore, and the concentration of bulk electrolyte.
A numerical model is developed to study electrolyte dependent kinetics in fuel cells. The model i... more A numerical model is developed to study electrolyte dependent kinetics in fuel cells. The model is based on the Poisson–Nernst–Planck (PNP) and generalized-Frumkin–Butler–Volmer (gFBV) equations, and is used to understand how the diffuse layer and ionic transport play a role in the performance difference between acidic and alkaline systems. The laminar flow fuel cell (LFFC) is used as the model fuel cell architecture to allow for the appropriate comparison of equivalent acidic and alkaline systems.
Abstract Human cardiac troponin I (hcTnI) and troponin T (hcTnT) are the biomarkers of choice for... more Abstract Human cardiac troponin I (hcTnI) and troponin T (hcTnT) are the biomarkers of choice for the diagnosis of cardiac diseases. In an effort to improve assay sensitivity, in this study we developed a novel approach to simultaneously detect hcTnI and hcTnT in homogenous solutions by monitoring enhanced-fluorescence-anisotropy changes.
Analytical solutions for the temperature distribution, heat transfer coefficient, and Nusselt num... more Analytical solutions for the temperature distribution, heat transfer coefficient, and Nusselt number of steady electroosmotic flows with an arbitrary pressure gradient are obtained for two-dimensional straight microchannels. The thermal analysis considers interaction among advective, diffusive, and Joule heating terms in order to obtain the thermally developing behavior of mixed electroosmotic and pressure-driven flows with isothermal boundary conditions.
Abstract The performance of a membraneless laminar flow micro fuel cell was evaluated under diffe... more Abstract The performance of a membraneless laminar flow micro fuel cell was evaluated under different operating conditions. The fuel cell was microfabricated in polydimethylsiloxane using standard soft-lithography techniques. It used methanol solution as the fuel for the anode side, and oxygen saturated sulphuric acid for the cathode. The parameters studied were the methanol concentration, flowrate, device width, and the concentration of sulphuric acid in the anode stream.
Two-phase pressure drop measurements are very difficult to make while the fluid is in non-equilib... more Two-phase pressure drop measurements are very difficult to make while the fluid is in non-equilibrium condition, ie while phase change is taking place. This is further complicated when an atomized liquid is introduced in the system at much higher velocity than other components such as liquid layer, vapor core, and entrained droplets. The purpose of this paper is to develop a model to predict the two-phase pressure characteristics in a mesochannel under various heat flux and liquid atomization conditions.
Abstract: Nanofluidics is a relatively new area of research, generally viewed as the study of the... more Abstract: Nanofluidics is a relatively new area of research, generally viewed as the study of the behavior, manipulation, and control of fluids at nanometer (< 100 nm) scales. At nanometer scales, fluids exhibit unique physical behaviors which are not present in larger structures. Nanofluidic structures have been successfully applied to technologies including analytical separations and the manipulation of proteins, RNA and DNA.
In the past decade, scientists have questioned the amount of petroleum products available to fuel... more In the past decade, scientists have questioned the amount of petroleum products available to fuel the world‟ s transportation sector at the rate of current consumption. Researchers have been tasked with not only finding more petroleum but also finding alternative energy sources. Methanol and ethanol have been heavily researched and have been shown to be able to produce energy on a very small scale. The fuel cell has been developed as an alternative energy source.
The stability of a toroidal pipe-reducer system is determined here from the solution of non-linea... more The stability of a toroidal pipe-reducer system is determined here from the solution of non-linear governing equations of axisymmetric deformations of shells of revolution. Numerical solutions are obtained by a modified version of the computer program developed by Uddin for solving the governing equations of axisymmetric shells by the multisegment method of integration. The interpretation of instability of the toroidal reducers is based on Thompson's theorems I and II.
This paper reports a hybrid electrohydrodynamic (EHD) inkjet printing technique that offers bette... more This paper reports a hybrid electrohydrodynamic (EHD) inkjet printing technique that offers better uniformity and stable operation in drop-ondemand (DOD) patterns compared to the conventional methods. This hybrid technique takes advantage of both electrohydrodynamic and piezoelectric methods where a piezoelectric actuator is used to supply a fixed volume of ink to the nozzle's exit for every jetting period, and the electrohydrodynamic technique is used to form ink droplets.
Abstract Recent studies show that reduction in cross-sectional area can be used to improve the co... more Abstract Recent studies show that reduction in cross-sectional area can be used to improve the concentration factor in microscale bioseparations. Due to simplicity in fabrication process, a step reduction in cross-sectional area is generally implemented in microchip to increase the concentration factor. But the sudden change in cross-sectional area can introduce significant band dispersion and distortion.
Chromium (VI)(Cr (VI)) contamination of soil and groundwater is considered a major environmental ... more Chromium (VI)(Cr (VI)) contamination of soil and groundwater is considered a major environmental concern. Bioreduction of Cr (VI) to chromium (III)(Cr (III)) can be considered an effective technology in remediating Cr (VI) contaminated sites. Among the Cr (VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) is relatively effective. Reduction of Cr (VI) by MR-1 is defined by the dual-enzyme kinetic model. Existing models are not able to simulate bioreduction of Cr (VI) by employing the dual-enzyme kinetic model.
This study focuses on understanding how the presence of particles, in homogeneous turbulence deca... more This study focuses on understanding how the presence of particles, in homogeneous turbulence decay, affects the dissipation of dissipation coefficient within the volume averaged dissipation transport equation. In developing this equation, the coefficient for dissipation of dissipation was assumed to be the sum of the single phase coefficient and an additional coefficient that is related to the effects of the dispersed phase.
Abstract Identification of the steady state is very challenging in isotachophoresis (ITP); especi... more Abstract Identification of the steady state is very challenging in isotachophoresis (ITP); especially in complex microgeometries, such as dog-leg channels or cross-channel junctions. In this work, an elastic matching method is applied to determine the quasi-steady state in microscale ITP. In the elastic matching method, the similarity between two profiles is calculated by comparing intensity distribution of two images or profiles.
Particle-laden turbulent flows are common in industrial applications. Large industries such as th... more Particle-laden turbulent flows are common in industrial applications. Large industries such as the chemical, pharmaceutical, agricultural, and mining industries can benefit from an understanding of particle-laden turbulent flows 1. Two-phase gas-solid suspension flows are prevalent in chemical engineering applications such as spray drying, cyclone separation, pneumatic conveying, pulverized coal gasification, and combustion 2.
Abstract This article presents an analytical solution for two-dimensional fluid flow in a rectang... more Abstract This article presents an analytical solution for two-dimensional fluid flow in a rectangular microchannel in the vicinity of a step change in the zeta (ζ) potential. The stream function is determined from the creeping flow approximation to the Navier-Stokes equations assuming a fixed volumetric axial flow, a constant electric field, and thin symmetric double layers. The resulting biharmonic equation is solved using a double-sided Laplace transformation, which is then inverted by Heaviside expansion.
Abstract This paper describes both the experimental application and 3-D numerical simulation of i... more Abstract This paper describes both the experimental application and 3-D numerical simulation of isotachophoresis (ITP) in a 3.2 cm long “cascade” poly (methyl methacrylate)(PMMA) microfluidic chip. The microchip includes 10× reductions in both the width and depth of the microchannel, which decreases the overall cross-sectional area by a factor of 100 between the inlet (cathode) and outlet (anode). A 3-D numerical simulation of ITP is outlined and is a first example of an ITP simulation in three dimensions.
Heat transfer characteristics are studied for a hybrid boiling case that combine features of spra... more Heat transfer characteristics are studied for a hybrid boiling case that combine features of spray cooling and flow boiling. In such a hybrid system, a liquid is atomized and the surrounding vapor is entrained into the droplet cone to provide an initial quality for enhanced boiling. An in-house experimental setup was developed to obtain surface temperature and heat flux measurements in a series of converged mesochannels for hybrid boiling.
On-chip isoelectric focusing (IEF) has been performed in both straight and dog-leg microchannels.... more On-chip isoelectric focusing (IEF) has been performed in both straight and dog-leg microchannels. Three-dimensional microfluidic chips were fabricated on poly di-methyl-siloxane (PDMS) using soft lithography and multilayer bonding techniques. Plasma oxidized PDMS channel surfaces were dynamically coated with methyl cellulose to discourage electroosmotic flow during separation and purification processes. In a straight microchannel, IEF was completed within 5 minutes at an applied electric field strength of 50 V/cm using ...
This paper describes the preconcentration of the biomarker cardiac troponin I (cTnI) and a fluore... more This paper describes the preconcentration of the biomarker cardiac troponin I (cTnI) and a fluorescent protein (R-phycoerythrin) using cationic isotachophoresis (ITP) in a 3.9 cm long poly (methyl methacrylate)(PMMA) microfluidic chip. The microfluidic chip includes a channel with a 5Â reduction in depth and a 10Â reduction in width. Thus, the overall cross-sectional area decreases by 50Â from inlet (anode) to outlet (cathode).
Abstract Recent experimental studies show that electrokinetic phenomena such as electroosmosis an... more Abstract Recent experimental studies show that electrokinetic phenomena such as electroosmosis and electrophoresis can be used to separate nanoparticles on the basis of their size and charge using nanopore-based devices. However, the efficient separation through a nanopore depends on a number of factors such as externally applied voltage, size and charge density of particle, size and charge density of membrane pore, and the concentration of bulk electrolyte.
A numerical model is developed to study electrolyte dependent kinetics in fuel cells. The model i... more A numerical model is developed to study electrolyte dependent kinetics in fuel cells. The model is based on the Poisson–Nernst–Planck (PNP) and generalized-Frumkin–Butler–Volmer (gFBV) equations, and is used to understand how the diffuse layer and ionic transport play a role in the performance difference between acidic and alkaline systems. The laminar flow fuel cell (LFFC) is used as the model fuel cell architecture to allow for the appropriate comparison of equivalent acidic and alkaline systems.
Abstract Human cardiac troponin I (hcTnI) and troponin T (hcTnT) are the biomarkers of choice for... more Abstract Human cardiac troponin I (hcTnI) and troponin T (hcTnT) are the biomarkers of choice for the diagnosis of cardiac diseases. In an effort to improve assay sensitivity, in this study we developed a novel approach to simultaneously detect hcTnI and hcTnT in homogenous solutions by monitoring enhanced-fluorescence-anisotropy changes.
Analytical solutions for the temperature distribution, heat transfer coefficient, and Nusselt num... more Analytical solutions for the temperature distribution, heat transfer coefficient, and Nusselt number of steady electroosmotic flows with an arbitrary pressure gradient are obtained for two-dimensional straight microchannels. The thermal analysis considers interaction among advective, diffusive, and Joule heating terms in order to obtain the thermally developing behavior of mixed electroosmotic and pressure-driven flows with isothermal boundary conditions.
Abstract The performance of a membraneless laminar flow micro fuel cell was evaluated under diffe... more Abstract The performance of a membraneless laminar flow micro fuel cell was evaluated under different operating conditions. The fuel cell was microfabricated in polydimethylsiloxane using standard soft-lithography techniques. It used methanol solution as the fuel for the anode side, and oxygen saturated sulphuric acid for the cathode. The parameters studied were the methanol concentration, flowrate, device width, and the concentration of sulphuric acid in the anode stream.
Two-phase pressure drop measurements are very difficult to make while the fluid is in non-equilib... more Two-phase pressure drop measurements are very difficult to make while the fluid is in non-equilibrium condition, ie while phase change is taking place. This is further complicated when an atomized liquid is introduced in the system at much higher velocity than other components such as liquid layer, vapor core, and entrained droplets. The purpose of this paper is to develop a model to predict the two-phase pressure characteristics in a mesochannel under various heat flux and liquid atomization conditions.
Abstract: Nanofluidics is a relatively new area of research, generally viewed as the study of the... more Abstract: Nanofluidics is a relatively new area of research, generally viewed as the study of the behavior, manipulation, and control of fluids at nanometer (< 100 nm) scales. At nanometer scales, fluids exhibit unique physical behaviors which are not present in larger structures. Nanofluidic structures have been successfully applied to technologies including analytical separations and the manipulation of proteins, RNA and DNA.
In the past decade, scientists have questioned the amount of petroleum products available to fuel... more In the past decade, scientists have questioned the amount of petroleum products available to fuel the world‟ s transportation sector at the rate of current consumption. Researchers have been tasked with not only finding more petroleum but also finding alternative energy sources. Methanol and ethanol have been heavily researched and have been shown to be able to produce energy on a very small scale. The fuel cell has been developed as an alternative energy source.
The stability of a toroidal pipe-reducer system is determined here from the solution of non-linea... more The stability of a toroidal pipe-reducer system is determined here from the solution of non-linear governing equations of axisymmetric deformations of shells of revolution. Numerical solutions are obtained by a modified version of the computer program developed by Uddin for solving the governing equations of axisymmetric shells by the multisegment method of integration. The interpretation of instability of the toroidal reducers is based on Thompson's theorems I and II.
This paper reports a hybrid electrohydrodynamic (EHD) inkjet printing technique that offers bette... more This paper reports a hybrid electrohydrodynamic (EHD) inkjet printing technique that offers better uniformity and stable operation in drop-ondemand (DOD) patterns compared to the conventional methods. This hybrid technique takes advantage of both electrohydrodynamic and piezoelectric methods where a piezoelectric actuator is used to supply a fixed volume of ink to the nozzle's exit for every jetting period, and the electrohydrodynamic technique is used to form ink droplets.
Abstract Recent studies show that reduction in cross-sectional area can be used to improve the co... more Abstract Recent studies show that reduction in cross-sectional area can be used to improve the concentration factor in microscale bioseparations. Due to simplicity in fabrication process, a step reduction in cross-sectional area is generally implemented in microchip to increase the concentration factor. But the sudden change in cross-sectional area can introduce significant band dispersion and distortion.
Chromium (VI)(Cr (VI)) contamination of soil and groundwater is considered a major environmental ... more Chromium (VI)(Cr (VI)) contamination of soil and groundwater is considered a major environmental concern. Bioreduction of Cr (VI) to chromium (III)(Cr (III)) can be considered an effective technology in remediating Cr (VI) contaminated sites. Among the Cr (VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) is relatively effective. Reduction of Cr (VI) by MR-1 is defined by the dual-enzyme kinetic model. Existing models are not able to simulate bioreduction of Cr (VI) by employing the dual-enzyme kinetic model.
This study focuses on understanding how the presence of particles, in homogeneous turbulence deca... more This study focuses on understanding how the presence of particles, in homogeneous turbulence decay, affects the dissipation of dissipation coefficient within the volume averaged dissipation transport equation. In developing this equation, the coefficient for dissipation of dissipation was assumed to be the sum of the single phase coefficient and an additional coefficient that is related to the effects of the dispersed phase.
Abstract Identification of the steady state is very challenging in isotachophoresis (ITP); especi... more Abstract Identification of the steady state is very challenging in isotachophoresis (ITP); especially in complex microgeometries, such as dog-leg channels or cross-channel junctions. In this work, an elastic matching method is applied to determine the quasi-steady state in microscale ITP. In the elastic matching method, the similarity between two profiles is calculated by comparing intensity distribution of two images or profiles.
Particle-laden turbulent flows are common in industrial applications. Large industries such as th... more Particle-laden turbulent flows are common in industrial applications. Large industries such as the chemical, pharmaceutical, agricultural, and mining industries can benefit from an understanding of particle-laden turbulent flows 1. Two-phase gas-solid suspension flows are prevalent in chemical engineering applications such as spray drying, cyclone separation, pneumatic conveying, pulverized coal gasification, and combustion 2.
Abstract This article presents an analytical solution for two-dimensional fluid flow in a rectang... more Abstract This article presents an analytical solution for two-dimensional fluid flow in a rectangular microchannel in the vicinity of a step change in the zeta (ζ) potential. The stream function is determined from the creeping flow approximation to the Navier-Stokes equations assuming a fixed volumetric axial flow, a constant electric field, and thin symmetric double layers. The resulting biharmonic equation is solved using a double-sided Laplace transformation, which is then inverted by Heaviside expansion.
Abstract This paper describes both the experimental application and 3-D numerical simulation of i... more Abstract This paper describes both the experimental application and 3-D numerical simulation of isotachophoresis (ITP) in a 3.2 cm long “cascade” poly (methyl methacrylate)(PMMA) microfluidic chip. The microchip includes 10× reductions in both the width and depth of the microchannel, which decreases the overall cross-sectional area by a factor of 100 between the inlet (cathode) and outlet (anode). A 3-D numerical simulation of ITP is outlined and is a first example of an ITP simulation in three dimensions.
Heat transfer characteristics are studied for a hybrid boiling case that combine features of spra... more Heat transfer characteristics are studied for a hybrid boiling case that combine features of spray cooling and flow boiling. In such a hybrid system, a liquid is atomized and the surrounding vapor is entrained into the droplet cone to provide an initial quality for enhanced boiling. An in-house experimental setup was developed to obtain surface temperature and heat flux measurements in a series of converged mesochannels for hybrid boiling.
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