Gunakala Sreedhara Rao | The University of the West Indies at St. Augustine Trinidad and Tobago (original) (raw)
Drafts by Gunakala Sreedhara Rao
Elsevier, 2022
In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnet... more In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnetic hyperthermia cancer therapy with intravenously-injected maghemite nanoparticles. The resulting suspension of nanoparticles in blood is considered to be a non-Newtonian nanofluid, and a two-phase model that considers Brownian and thermophoretic effects is considered. The geometrical domain is comprised of a blood vessel region, cancerous and non-cancerous (prostate or muscle) tissue regions, and a region of fat tissue. The mixed finite element technique is utilized for solving the governing equations and their associated initial and boundary conditions; triangular quadratic elements are chosen for the temperature, velocity and nanoparticle volume fraction approximations, whereas triangular linear elements are selected for the pressure approximation. Based on this numerical solution, we examine the impact of the nanoparticle volume fraction at the inlet of the blood and magnetic field oscillation frequency on heat transfer and nanoparticle transport. The findings of this study indicate that in the prostate and muscle tissue cases, the nanoparticle distribution non-uniformity and the tissue and blood vessel temperatures are increased, and the average pressure is reduced, by increasing the inlet nanoparticle concentration and magnetic field oscillation frequency. In the muscle tissue case, the mean flow velocity can be increased by increasing the inlet nanoparticle concentration and decreasing the magnetic field oscillation frequency. Based on these findings, recommendations are made for improving the effectiveness of magnetic nanoparticle hyperthermia in cancerous muscle and prostate tissues. The research conducted in this work is motivated by the need for a better understanding of the factors impacting nanoparticle transport in tissues and heat generation during magnetic hyperthermia. Using the mathematical model developed herein, tissue temperatures attained under intravenous magnetic hyperthermia treatment can be accurately predicted.
Elsevier, 2020
We examine the combined effect of variable viscosity, velocity slip, and the couple stress lubric... more We examine the combined effect of variable viscosity, velocity slip, and the couple stress lubricant on a finite journal bearing. In our model, we utilize the Stokes micro-continuum theorem, the Barus formula, and an artificial (homogeneous) slip surface to improve the lubrication performance. Three cases of slip have also been considered: on the journal, the bearing, and both journal and bearing. The finite difference method is used to solve the equations numerically. The results indicate that the highest pressure occurs with slip on the bearing, and the lowest pressure occurs with slip on the journal. A high piezo-viscosity enhances the pressure and load-carrying capacity. Also, the slip parameter improves the load-carrying capacity. With slip on the bearing only, the frictional parameter decreases significantly.
Elsevier, 2020
In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 ... more In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 or FePt) nanoparticle hyperthermia is considered for the treatment of muscle and prostate tumours. The blood-nanoparticle suspension is described as a non-Newtonian (Quemada) nanofluid, and the effects of thermophoresis and Brownian motion are considered. The blood vessel region is surrounded by a cancerous (muscle or prostate) tumour region, a non-cancerous (muscle or prostate) region and a fat layer. Heat is generated within these tissue regions using an external alternating magnetic field. A numerical solution of the problem is obtained using the mixed finite element method with P 2 À P 1 Taylor-Hood elements. Using this numerical solution, the influence of tumour size, blood vessel radius and haematocrit on blood flow, convective heat transfer, nanoparticle mass transport and blood pressure is examined.
Elsevier, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, coup... more In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
Elsevier, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, coup... more In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
Papers by Gunakala Sreedhara Rao
Proceedings of the International Conference on Emerging Trends in Engineering & Technology (IConETech-2020), 2020
In this paper, we examine the combined effect of a non-Newtonian couple-stress lubricant, and a m... more In this paper, we examine the combined effect of a non-Newtonian couple-stress lubricant, and a magnetic fluid, together with velocity-slip and piezo-viscosity, has on the lubrication characteristics of a finite journal bearing. Using the Stokes micro-continuum theorem and the Barus formula with an artificial (homogeneous) slip surface, we investigate the load-carrying ability, pressure distribution, and frictional coefficient of the bearing. Our results indicate that the piezo-viscosity parameter improves the maximum magnetic and hydrodynamic pressures of the journal bearing. The combined effect also significantly enhances the bearing characteristics.
Applied Thermal Engineering, 2017
Ain Shams Engineering Journal, 2020
Materials Today: Proceedings, 2022
In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnet... more In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnetic hyperthermia cancer therapy with intravenously-injected maghemite nanoparticles. The resulting suspension of nanoparticles in blood is considered to be a non-Newtonian nanofluid, and a two-phase model that considers Brownian and thermophoretic effects is considered. The geometrical domain is comprised of a blood vessel region, cancerous and non-cancerous (prostate or muscle) tissue regions, and a region of fat tissue. The mixed finite element technique is utilized for solving the governing equations and their associated initial and boundary conditions; triangular quadratic elements are chosen for the temperature, velocity and nanoparticle volume fraction approximations, whereas triangular linear elements are selected for the pressure approximation. Based on this numerical solution, we examine the impact of the nanoparticle volume fraction at the inlet of the blood and magnetic field oscillation frequency on heat transfer and nanoparticle transport. The findings of this study indicate that in the prostate and muscle tissue cases, the nanoparticle distribution non-uniformity and the tissue and blood vessel temperatures are increased, and the average pressure is reduced, by increasing the inlet nanoparticle concentration and magnetic field oscillation frequency. In the muscle tissue case, the mean flow velocity can be increased by increasing the inlet nanoparticle concentration and decreasing the magnetic field oscillation frequency. Based on these findings, recommendations are made for improving the effectiveness of magnetic nanoparticle hyperthermia in cancerous muscle and prostate tissues. The research conducted in this work is motivated by the need for a better understanding of the factors impacting nanoparticle transport in tissues and heat generation during magnetic hyperthermia. Using the mathematical model developed herein, tissue temperatures attained under intravenous magnetic hyperthermia treatment can be accurately predicted.
Materials Today: Proceedings, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, coup... more In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
Alexandria Engineering Journal, 2021
Abstract In the present work, a two-phase mathematical model of intravenous magnetic ( Fe 3 O 4 ,... more Abstract In the present work, a two-phase mathematical model of intravenous magnetic ( Fe 3 O 4 , Fe 2 O 3 or FePt) nanoparticle hyperthermia is considered for the treatment of muscle and prostate tumours. The blood-nanoparticle suspension is described as a non-Newtonian (Quemada) nanofluid, and the effects of thermophoresis and Brownian motion are considered. The blood vessel region is surrounded by a cancerous (muscle or prostate) tumour region, a non-cancerous (muscle or prostate) region and a fat layer. Heat is generated within these tissue regions using an external alternating magnetic field. A numerical solution of the problem is obtained using the mixed finite element method with P 2 - P 1 Taylor-Hood elements. Using this numerical solution, the influence of tumour size, blood vessel radius and haematocrit on blood flow, convective heat transfer, nanoparticle mass transport and blood pressure is examined.
In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 ... more In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 or FePt) nanoparticle hyperthermia is considered for the treatment of muscle and prostate tumours. The blood-nanoparticle suspension is described as a non-Newtonian (Quemada) nanofluid, and the effects of thermophoresis and Brownian motion are considered. The blood vessel region is surrounded by a cancerous (muscle or prostate) tumour region, a non-cancerous (muscle or prostate) region and a fat layer. Heat is generated within these tissue regions using an external alternating magnetic field. A numerical solution of the problem is obtained using the mixed finite element method with P 2 À P 1 Taylor-Hood elements. Using this numerical solution, the influence of tumour size, blood vessel radius and haematocrit on blood flow, convective heat transfer, nanoparticle mass transport and blood pressure is examined.
Elsevier, 2022
In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnet... more In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnetic hyperthermia cancer therapy with intravenously-injected maghemite nanoparticles. The resulting suspension of nanoparticles in blood is considered to be a non-Newtonian nanofluid, and a two-phase model that considers Brownian and thermophoretic effects is considered. The geometrical domain is comprised of a blood vessel region, cancerous and non-cancerous (prostate or muscle) tissue regions, and a region of fat tissue. The mixed finite element technique is utilized for solving the governing equations and their associated initial and boundary conditions; triangular quadratic elements are chosen for the temperature, velocity and nanoparticle volume fraction approximations, whereas triangular linear elements are selected for the pressure approximation. Based on this numerical solution, we examine the impact of the nanoparticle volume fraction at the inlet of the blood and magnetic field oscillation frequency on heat transfer and nanoparticle transport. The findings of this study indicate that in the prostate and muscle tissue cases, the nanoparticle distribution non-uniformity and the tissue and blood vessel temperatures are increased, and the average pressure is reduced, by increasing the inlet nanoparticle concentration and magnetic field oscillation frequency. In the muscle tissue case, the mean flow velocity can be increased by increasing the inlet nanoparticle concentration and decreasing the magnetic field oscillation frequency. Based on these findings, recommendations are made for improving the effectiveness of magnetic nanoparticle hyperthermia in cancerous muscle and prostate tissues. The research conducted in this work is motivated by the need for a better understanding of the factors impacting nanoparticle transport in tissues and heat generation during magnetic hyperthermia. Using the mathematical model developed herein, tissue temperatures attained under intravenous magnetic hyperthermia treatment can be accurately predicted.
Elsevier, 2020
We examine the combined effect of variable viscosity, velocity slip, and the couple stress lubric... more We examine the combined effect of variable viscosity, velocity slip, and the couple stress lubricant on a finite journal bearing. In our model, we utilize the Stokes micro-continuum theorem, the Barus formula, and an artificial (homogeneous) slip surface to improve the lubrication performance. Three cases of slip have also been considered: on the journal, the bearing, and both journal and bearing. The finite difference method is used to solve the equations numerically. The results indicate that the highest pressure occurs with slip on the bearing, and the lowest pressure occurs with slip on the journal. A high piezo-viscosity enhances the pressure and load-carrying capacity. Also, the slip parameter improves the load-carrying capacity. With slip on the bearing only, the frictional parameter decreases significantly.
Elsevier, 2020
In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 ... more In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 or FePt) nanoparticle hyperthermia is considered for the treatment of muscle and prostate tumours. The blood-nanoparticle suspension is described as a non-Newtonian (Quemada) nanofluid, and the effects of thermophoresis and Brownian motion are considered. The blood vessel region is surrounded by a cancerous (muscle or prostate) tumour region, a non-cancerous (muscle or prostate) region and a fat layer. Heat is generated within these tissue regions using an external alternating magnetic field. A numerical solution of the problem is obtained using the mixed finite element method with P 2 À P 1 Taylor-Hood elements. Using this numerical solution, the influence of tumour size, blood vessel radius and haematocrit on blood flow, convective heat transfer, nanoparticle mass transport and blood pressure is examined.
Elsevier, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, coup... more In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
Elsevier, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, coup... more In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
Proceedings of the International Conference on Emerging Trends in Engineering & Technology (IConETech-2020), 2020
In this paper, we examine the combined effect of a non-Newtonian couple-stress lubricant, and a m... more In this paper, we examine the combined effect of a non-Newtonian couple-stress lubricant, and a magnetic fluid, together with velocity-slip and piezo-viscosity, has on the lubrication characteristics of a finite journal bearing. Using the Stokes micro-continuum theorem and the Barus formula with an artificial (homogeneous) slip surface, we investigate the load-carrying ability, pressure distribution, and frictional coefficient of the bearing. Our results indicate that the piezo-viscosity parameter improves the maximum magnetic and hydrodynamic pressures of the journal bearing. The combined effect also significantly enhances the bearing characteristics.
Applied Thermal Engineering, 2017
Ain Shams Engineering Journal, 2020
Materials Today: Proceedings, 2022
In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnet... more In this work, we investigate heat transfer phenomena in muscle and prostate tissues during magnetic hyperthermia cancer therapy with intravenously-injected maghemite nanoparticles. The resulting suspension of nanoparticles in blood is considered to be a non-Newtonian nanofluid, and a two-phase model that considers Brownian and thermophoretic effects is considered. The geometrical domain is comprised of a blood vessel region, cancerous and non-cancerous (prostate or muscle) tissue regions, and a region of fat tissue. The mixed finite element technique is utilized for solving the governing equations and their associated initial and boundary conditions; triangular quadratic elements are chosen for the temperature, velocity and nanoparticle volume fraction approximations, whereas triangular linear elements are selected for the pressure approximation. Based on this numerical solution, we examine the impact of the nanoparticle volume fraction at the inlet of the blood and magnetic field oscillation frequency on heat transfer and nanoparticle transport. The findings of this study indicate that in the prostate and muscle tissue cases, the nanoparticle distribution non-uniformity and the tissue and blood vessel temperatures are increased, and the average pressure is reduced, by increasing the inlet nanoparticle concentration and magnetic field oscillation frequency. In the muscle tissue case, the mean flow velocity can be increased by increasing the inlet nanoparticle concentration and decreasing the magnetic field oscillation frequency. Based on these findings, recommendations are made for improving the effectiveness of magnetic nanoparticle hyperthermia in cancerous muscle and prostate tissues. The research conducted in this work is motivated by the need for a better understanding of the factors impacting nanoparticle transport in tissues and heat generation during magnetic hyperthermia. Using the mathematical model developed herein, tissue temperatures attained under intravenous magnetic hyperthermia treatment can be accurately predicted.
Materials Today: Proceedings, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, coup... more In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
Alexandria Engineering Journal, 2021
Abstract In the present work, a two-phase mathematical model of intravenous magnetic ( Fe 3 O 4 ,... more Abstract In the present work, a two-phase mathematical model of intravenous magnetic ( Fe 3 O 4 , Fe 2 O 3 or FePt) nanoparticle hyperthermia is considered for the treatment of muscle and prostate tumours. The blood-nanoparticle suspension is described as a non-Newtonian (Quemada) nanofluid, and the effects of thermophoresis and Brownian motion are considered. The blood vessel region is surrounded by a cancerous (muscle or prostate) tumour region, a non-cancerous (muscle or prostate) region and a fat layer. Heat is generated within these tissue regions using an external alternating magnetic field. A numerical solution of the problem is obtained using the mixed finite element method with P 2 - P 1 Taylor-Hood elements. Using this numerical solution, the influence of tumour size, blood vessel radius and haematocrit on blood flow, convective heat transfer, nanoparticle mass transport and blood pressure is examined.
In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 ... more In the present work, a two-phase mathematical model of intravenous magnetic (Fe 3 O 4 ; Fe 2 O 3 or FePt) nanoparticle hyperthermia is considered for the treatment of muscle and prostate tumours. The blood-nanoparticle suspension is described as a non-Newtonian (Quemada) nanofluid, and the effects of thermophoresis and Brownian motion are considered. The blood vessel region is surrounded by a cancerous (muscle or prostate) tumour region, a non-cancerous (muscle or prostate) region and a fat layer. Heat is generated within these tissue regions using an external alternating magnetic field. A numerical solution of the problem is obtained using the mixed finite element method with P 2 À P 1 Taylor-Hood elements. Using this numerical solution, the influence of tumour size, blood vessel radius and haematocrit on blood flow, convective heat transfer, nanoparticle mass transport and blood pressure is examined.