Abstract
In this study, a mathematical model is developed to scrutinize the transient magnetic flow of Cross nanoliquid past a stretching sheet with thermal radiation effects. Binary chemical ...reactions and heat source/sink effects along with convective boundary condition are also taken into the consideration. Appropriate similarity transformations are utilized to transform partial differential equations (PDE’s) into ordinary ones and then numerically tackled by shooting method. The impacts of different emerging parameters on the thermal, concentration, velocity, and micro-rotation profiles are incorporated and discussed in detail by means of graphs. Results reveal that, the escalation in magnetic parameter and Rayleigh number slowdowns the velocity and momentum of the fluid. The increase in Biot number, radiation and heat sink/source parameters upsurges the thermal boundary but, converse trend is seen for escalating Prandtl number. The density number of motile microorganisms acts as a growing function of bioconvection Lewis number and declining function of bioconvection Peclet number.
Scientists and engineers have experimentally noticed that the heat transfer is essential for preeminence of multi scale production. Thermal properties are naturally accomplished via continuous phase ...liquids. Its importance is nevertheless constrained by the low capacity for heat transfer. Consequently, the increased heat transference phenomenon must be employed to accomplish the expected results. In this regard, the nature of the Arrhenius activation energy in the flow of hybrid nanoliquid over a curved stretchable surface (CSS) in the presence of exponential heat generation is scrutinized. The fluid suspended with Manganese zinc ferrite (MnZnFe2O4) and Nickel zinc ferrite (NiZnFe2O4) as nanoparticles along with Kerosene oil as a base liquid is accounted in this study. The described flow equations are transformed by using appropriate similarity variables and then they are tackled with Runge Kutta Fehlberg‐45 (RKF‐45) scheme by adopting shooting process. It can be concluded that, the increasing values of Biot number and heat source/sink parameter improves the thermal gradient. Further, hybrid nanofluid shows high heat transfer rate when compared to nanoliquid for improved values of heat source/sink parameter.
Scientists and engineers have experimentally noticed that the heat transfer is essential for preeminence of multi scale production. Thermal properties are naturally accomplished via continuous phase liquids. Its importance is nevertheless constrained by the low capacity for heat transfer. Consequently, the increased heat transference phenomenon must be employed to accomplish the expected results. In this regard, the nature of the Arrhenius activation energy in the flow of hybrid nanoliquid over a curved stretchable surface (CSS) in the presence of exponential heat generation is scrutinized.…
This study reports an incompressible electrically conducting Casson–Maxwell fluid flow confined across two uniformly stretchable disks. Buongiorno nanofluid model is implemented in the fluid flow. ...Cattaneo–Christov theory of double-diffusion is characterized through the heat and mass equations. Velocity, thermal and concentration slip conditions are executed at the lower stretchable disk. The flow model is dimensionalized through the similarity functions and then numerical solution is attained by RKF-45 scheme combined with shooting technique. The results of physical parameters are discussed by plotting the effects of such parameters on velocity, thermal and concentration fields. The results revealed that the Maxwell liquid is highly effected by Lorentz force than the Casson liquid. Thermal gradient of Maxwell liquid is highly influenced by stretching ratio parameter when compared to Casson fluid. Increase in Casson parameter and Deborah number declines the velocity gradient. Rise in the values of Brownian motion parameter declines the concentration gradient. Finally, the upsurge in thermal relaxation time parameter enhances the thermal gradient quickly in absence of thermal slip parameter.
This study mainly focusses on the rheological properties of the nanofluids by using Koo–Kleinstreuer–Li model. The nanofluids have been proposed as viable replacements to traditional fluids due to ...their increased heat transport capacity. In this regard, the influence of non-uniform heat sink/source and thermal radiation effects on the nanoliquid flow past a stretching sheet is studied in the presence of chemical reaction and magnetic dipole. The defined flow equations are transformed to ordinary differential equations by using appropriate similarity variables and then they are numerically tackled with Runge Kutta Fehlberg-45 (RKF-45) scheme by adopting shooting process. The graphical outcomes of the velocity, thermal, concentration profiles, drag force, Sherwood number and Nusselt number are found to get an obvious insight into the existing boundary layer flow problem. The outcomes reveal that, the gain in values of radiation parameter improves the thermal profile due to the production of inner heat. The rise in Biot number improves the thermal boundary layer region which automatically boosts up the thermal profile. Further, the escalation in space-dependent internal heat sink/source parameter deteriorates the rate of heat transfer.
This communication discusses the Marangoni convection of hybrid nanofluid. Hybrid nanofluid is made up of two nanoparticles (MnZiFe2O4-NiZnFe2O4) and one base fluid (H2O). Darcy Forchheimer porous ...medium effect is inserted in momentum equation. Entropy generation in the flow due to heat transfer irreversibility, mass transfer irreversibility and viscous dissipation irreversibility is calculated and examined against pertinent parameters. Activation energy effect is applied in concentration equation. Bejan number effect is calculated to examine that which irreversibility factor is dominant. Transformations are applied to form the required governing equations from PDE’s. Effect of pertinent parameters on velocity, concentration, skin friction, temperature, entropy generation, Nusselt number and Bejan number are studied graphically. Velocity of the fluid is decreasing due to increase in porosity parameter, Forchheimer number and Marangoni ratio parameter. Temperature rises for Eckert number and nanoparticles volume fraction of both nanoparticles. Concentration rises for activation energy parameter and reduces for chemical reaction parameter. Entropy generation increases for Marangoni ratio parameter, diffusion parameter and Brinkman number.
The enhancement of heat transfer is an important factor in heat exchangers, nuclear reactors, electric coolers and solar collectors. The enhance in rate of heat and mass transfer can be achieved by ...choosing suitable nanofluid or ferromagnetic fluid as an active liquid. In this connection, we have investigated the ferromagnetic nanofluid flow past a flat elastic sheet with porous medium and chemical reaction. Further, CuO−H2O nanofluid is considered and simulated through the Koo and Kleinstreuer‐Li (KKL) nanofluid model. The described governing equations are reduced to ordinary differential equations (ODE's) by means of apt similarity transformations and then they are numerically tackled using Runge Kutta Fehlberg‐45 (RKF‐45) scheme along with shooting method. The graphical results of the velocity, concentration and thermal profiles along with skin friction, Sherwood and Nusselt numbers are found to get an obvious insight of the existing boundary flow problem. The results reveal that, increasing values of ferromagnetic interaction parameter decays the velocity gradient but converse trend is depicted in thermal gradient due to the frictional heating between fluid layers. The increasing values of porosity parameter slowdowns the rate of heat transfer and velocity gradient.
The enhancement of heat transfer is an important factor in heat exchangers, nuclear reactors, electric coolers and solar collectors. The enhance in rate of heat and mass transfer can be achieved by choosing suitable nanofluid or ferromagnetic fluid as an active liquid. In this connection, we have investigated the ferromagnetic nanofluid flow past a flat elastic sheet with porous medium and chemical reaction. Further, CuO−H2O nanofluid is considered and simulated through the Koo and Kleinstreuer‐Li (KKL) nanofluid model.…
Stefan blowing phenomenon in electrically conducting Sutterby material flow over stretchable rotating disk is demonstrated in this research. Cattaneo-Christov (CC) model of energy diffusion is ...adopted to analyze the heat transmission. Buongiorno model is carried out to evaluate the involvement of nanoparticles. The formulated system of partial differential expressions is re-structured by the enactment of similarity functions. Runge–Kutta-Fehlberg (RKF) fourth-fifth order process has been executed to communicate the solution of velocity, thermal and solutal fields. The velocity, concentration, thermal fields, skin friction, rate of mass and heat transportations are explored for the embedded non-dimensional parameters graphically. Result reveals that the rise in Stefan blowing factor leads to an enhancement in radial and tangential velocities gradients. The velocity of nanomaterial is reduced by the incrementing material parameter values. The augmenting magnetic parameter values reduced the liquid velocity but improves the temperature. The thermophoretic force and Brownian motion involvement resulted the higher thermal field.
BBV152 is a whole-virion inactivated SARS-CoV-2 vaccine that has been deployed in India. The results of the phase 3 trial have shown clinical efficacy of BBV152. We aimed to evaluate the ...effectiveness of BBV152 against symptomatic RT-PCR-confirmed SARS-CoV-2 infection.
We conducted a test-negative, case-control study among employees of the All India Institute of Medical Sciences (a tertiary care hospital in New Delhi, India), who had symptoms suggestive of COVID-19 and had an RT-PCR test for SARS-CoV-2 during the peak of the second wave of the COVID-19 pandemic in India between April 15 and May 15, 2021. Cases (test-positives) and controls (test-negatives) were matched (1:1) on the basis of age and gender. The odds of vaccination with BBV152 were compared between cases and controls and adjusted for level of occupational exposure (to COVID-19), previous SARS-CoV-2 infection, and calendar time, using conditional logistic regression. The primary outcome was effectiveness of two doses of BBV152 (with the second dose received at least 14 days before testing) in reducing the odds of symptomatic RT-PCR-confirmed SARS-CoV-2 infection, expressed as (1 – odds ratio) × 100%.
Between April 15 and May 15, 2021, 3732 individuals had an RT-PCR test. Of these, 2714 symptomatic employees had data on vaccination status, and 1068 matched case-control pairs were available for analysis. The adjusted effectiveness of BBV152 against symptomatic COVID-19 after two doses administered at least 14 days before testing was 50% (95% CI 33–62; p<0·0001). The adjusted effectiveness of two doses administered at least 28 days before testing was 46% (95% CI 22–62) and administered at least 42 days before testing was 57% (21–76). After excluding participants with previous SARS-CoV-2 infections, the adjusted effectiveness of two doses administered at least 14 days before testing was 47% (95% CI 29–61).
This study shows the effectiveness of two doses of BBV152 against symptomatic COVID-19 in the context of a huge surge in cases, presumably dominated by the potentially immune-evasive delta (B.1.617.2) variant of SARS-CoV-2. Our findings support the ongoing roll-out of this vaccine to help control the spread of SARS-CoV-2, while continuing the emphasis on adherence to non-pharmacological measures.
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For the Hindi translation of the abstract see Supplementary Materials section.
Nanofluid is treated as a smart fluid that is useful for heat and mass transfer enhancement, which is paramount in several electronics, biomedical, transportation as well as industrial applications. ...In view of this, in the current analysis we scrutinize the flow of nanofluid over a curved stretching sheet. The noted novelty of this work is to discuss the heat and mass transfer in nanofluid flow along with the activation energy. Further, CuO with water-based nanofluid is considered in the modelling. The viscosity and effective thermal conductivity of fluid flow suspended by nanoparticles are scrutinized by Koo–Kleinstreuer–Li (KKL) model. By employing suitable similarity transformations, the governing equations of momentum, thermal and concentration of nanoparticle are converted into ordinary differential equations and then they are solved with Runge–Kutta-Fehlberg-45 (RKF-45) process along with shooting method. The impact of pertinent non-dimensional parameters is attained and illustrated with the help of graphs. The results reveal that, the heightening of Biot number and curvature parameter heightens the thermal gradient. The mass transfer decreases as the Schmidt number and chemical reaction rate parameter increases. The upsurge in activation energy parameter declines the mass transfer.
•Flow and heat transfer characteristics of nanoliquid by using Koo–Kleinstreuer and Li (KKL) correlation is studied.•Modified Fourier heat flux law is utilised to model the temperature ...equation.•Viscous dissipation, activation energy and chemical reaction effects are used to study heat and mass transfer characteristics.•Accurate numerical solutions are obtained using Runge-Kutta-Fehlberg fourth fifth order along with shooting technique.
The objective of the current paper is to study the two-dimensional, incompressible nanofluid flow over a curved stretching sheet coiled in a circle. Further, the impact of dispersion of nanoparticle CuO in base liquid water on the performance of flow, thermal conductivity and mass transfer using KKL model in the presence of Cattaneo-Christov heat flux and activation energy is deliberated. A curvilinear coordinate system is used to develop the mathematical model describing the flow phenomena in the form of partial differential equations. Further, by means of apt similarity transformations the governing boundary value problems are reduced to ordinary differential equations. Mathematical computations are simplified using Runge-Kutta-Fehlberg-45(RKF-45) process by adopting shooting method. Graphical illustrations of velocity, temperature, concentration gradients for various pertinent parameters are presented. The result reveals that, the heightening of porosity parameter heightens the thermal gradient but converse trend is depicted in velocity gradient. The enhancing values of Schmidt number and chemical reaction rate parameter declines concentration gradient whereas converse trend is depicted for upsurge in activation energy parameter.
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