The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat tr...The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat transfer.Homogeneous–heterogeneous reaction and radiative effects have been further taken into account to reconnoiterproperties of heat transfer.Melting heat transfer and phenomenon of homogeneous–heterogeneous reaction have engrossed widespread utilization in purification of metals,welding process,electroslag melting,biochemical systems,catalysis and several industrial developments.Suitable transformations are utilized to attain a scheme of ordinary differential equations possessing exceedingly nonlinear nature.Homotopic process is employed to develop convergent solutions of the resulting problem.Discussion regarding velocity,thermal field and concentration distribution for several involved parameters is pivotal part.Graphical behaviors of skin friction coefficient and Nusselt number are also portrayed.Concentration of the reactants is found to depreciate as a result of strength of both heterogeneous and homogeneous reaction parameters.With existence of melting phenomenon,declining attitude of fluid temperature is observed for higher radiation parameter.展开更多
Combined effects of Soret(thermal-diffusion) and Dufour(diffusion-thermo) in MHD stagnation point flow by a permeable stretching cylinder were studied. Analysis was examined in the presence of heat generation/absorpti...Combined effects of Soret(thermal-diffusion) and Dufour(diffusion-thermo) in MHD stagnation point flow by a permeable stretching cylinder were studied. Analysis was examined in the presence of heat generation/absorption and chemical reaction. The laws of conservation of mass, momentum, energy and concentration are found to lead to the mathematical development of the problem. Suitable transformations were used to convert the nonlinear partial differential equations into the ordinary differential equations. The series solutions of boundary layer equations through momentum, energy and concentration equations were obtained.Convergence of the developed series solutions was discussed via plots and numerical values. The behaviors of different physical parameters on the velocity components, temperature and concentration were obtained. Numerical values of Nusselt number, skin friction and Sherwood number with different parameters were computed and analyzed. It is found that Dufour and Soret numbers result in the enhancement of temperature and concentration distributions, respectively.展开更多
The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics effects.The processes of heat and mass transport incorporate the temperature-depend...The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics effects.The processes of heat and mass transport incorporate the temperature-dependent binary chemical reaction with modified Arrhenius theory of activation energy function which is not yet disclosed for squeezing flow mechanism.The flow,heat and mass regime are exposed to be governed via dimensionless,highly non-linear,ordinary differential equations (ODEs) under no-slip walls boundary conditions.A well-tempered analytical convergent procedure is adopted for the solutions of boundary value problem.A detailed study is accounted through graphs in the form of flow velocity field,temperature and fluid concentration distributions for various emerging parameters of enormous interest.Skin-friction,Nusselt and Sherwood numbers have been acquired and disclosed through plots.The results indicate that fluid temperature follows an increasing trend with dominant dimensionless reaction rate σ and activation energy parameter E.However,an increment in σ and E parameters is found to decline in fluid concentration.The current study arises numerous engineering and industrial processes including polymer industry,compression and injection shaping,lubrication system,formation of paper sheets,thin fiber,molding of plastic sheets.In the area of chemical engineering,geothermal engineering,cooling of nuclear reacting,nuclear or chemical system,bimolecular reactions,biochemical process and electrically conducting polymeric flows can be controlled by utilizing magnetic fields.Motivated by such applications,the proposed study has been developed.展开更多
The present study is carried out to see the thermal-diffusion(Dufour) and diffusion-thermo(Soret) effects on the mixed convection boundary layer flow of viscoelastic nanofluid flow over a vertical stretching surface i...The present study is carried out to see the thermal-diffusion(Dufour) and diffusion-thermo(Soret) effects on the mixed convection boundary layer flow of viscoelastic nanofluid flow over a vertical stretching surface in a porous medium. Optimal homotopy analysis method(OHAM) is best candidate to handle highly nonlinear system of differential equations obtained from boundary layer partial differential equations via appropriate transformations. Graphical illustrations depicting different physical arising parameters against velocity, temperature and concentration distributions with required discussion have also been added. Numerically calculated values of skin friction coefficient, local Nusselt and Sherwood numbers are given in the form of table and well argued. It is found that nanofluid velocity increases with increase in mixed convective and viscoelastic parameters but it decreases with the increasing values of porosity parameter. Also, it is observed that Dufour number has opposite behavior on temperature and concentration profiles.展开更多
This article scrutinizes the features of viscous dissipation in the stagnation point ?ow past through a linearly stretched Riga wall by implementing Cattaneo-Christov heat ?ux model. Viscous dissipation is carried out...This article scrutinizes the features of viscous dissipation in the stagnation point ?ow past through a linearly stretched Riga wall by implementing Cattaneo-Christov heat ?ux model. Viscous dissipation is carried out in Cattaneo-Christov diffusion analysis for the ?rst time in this letter. As a result of Cattaneo-Christov model, some extra terms of viscous dissipation are appeared in the energy equation. These extra terms of viscous dissipation are missing in the literature. On the utilization of suitable transformations, the equations governing the problem are reduced under the boundary layer approximation into the non-linear and dimensionless ordinary differential equations. Convergent approach is utilized to solve the dimensionless governing equations. The solution thus acquired is used to highlight the effects of emerging parameters on velocity distribution and ?uid's temperature through the graphs. Features of the drag force(or skin friction co-e?cient) are graphically interpreted. It is noticed that the presence of modi?ed Hartman number helps to reduce the ?uid's temperature but enhances the velocity pro?le. Further an enlargement in the value of thermal time relaxation parameter helps to decrease the temperature distribution.展开更多
This letter describes the characteristics of homogeneous-heterogeneous re- action in the boundary layer flow of a Jeffrey fluid due to an impermeable horizontal stretching sheet. An analysis is carried out through the...This letter describes the characteristics of homogeneous-heterogeneous re- action in the boundary layer flow of a Jeffrey fluid due to an impermeable horizontal stretching sheet. An analysis is carried out through the similar values of reactant and auto catalyst diffusion coefficients. Heat released by the reaction is not accounted. The exact solution for the flow of the Jeffrey fluid is constructed. The series solution for the concentration equation is derived. The velocity and concentration fields reflecting the impact of interesting parameters are plotted and examined.展开更多
A thin film of blended poly-N-epoxypropylcarbazole（PEPC）（25 wt.%）,nickel phthalocyanine（NiPc）（50 wt.%） and ZnO nano-powder（25 wt.%） in benzene（5 wt.%） was spin-coated on a glass substrate with silver elect...A thin film of blended poly-N-epoxypropylcarbazole（PEPC）（25 wt.%）,nickel phthalocyanine（NiPc）（50 wt.%） and ZnO nano-powder（25 wt.%） in benzene（5 wt.%） was spin-coated on a glass substrate with silver electrodes to produce a surface-type Ag/PEPC/NiPc/ZnO/Ag capacitive and resistive sensor.Sensors with two different PEPC/NiPc/ZnO film thicknesses（330 and 400 nm） were fabricated and compared.The effects of humidity on capacitance and resistance of the Ag/PEPC/NiPc/ZnO/Ag sensors were investigated at two frequencies of the applied voltage：120 Hz and 1 kHz.It was observed that at 120 Hz under humidity of up to 95%RH the capacitance of the sensors increased by 540 times and resistance decreased by 450 times with respect to humidity conditions of 50%RH. It was found that the sensor with a thinner semiconducting film（330 nm） was more sensitive than the sensor with a thicker film（400 nm）.The sensitivity was improved when the sensor was used at a lower frequency as compared with a high frequency.It is assumed that the humidity response of the sensors is associated with absorption of water vapors and doping of water molecules in the semiconductor blend layer.This had been proven by simulation of the capacitance-humidity relationship.展开更多
Au/cellulose-PEPC/Au surface-type humidity sensors were fabricated by drop-casting cellulose and poly-N-epoxypropylcarbazole （PEPC） blend thin films. A blend of 2wt% of each cellulose and PEPC in benzol was used for...Au/cellulose-PEPC/Au surface-type humidity sensors were fabricated by drop-casting cellulose and poly-N-epoxypropylcarbazole （PEPC） blend thin films. A blend of 2wt% of each cellulose and PEPC in benzol was used for the deposition of humidity sensing films. Blend films were deposited on glass substrates with preliminary deposited surface-type gold electrodes. Films of different thicknesses of cellulose and PEPC composite were deposited by drop-casting technique. A change in electrical resistance and capacitance of the fabricated devices was observed by increasing the relative humidity in the range of 0-95% RH. It was observed that the capacitances of the sensors increase, while their resistances decrease with increasing the relative humidity. The sensors were connected to op-amp square wave oscillators. It was observed that with increasing the relative humidity, the oscillator＇s frequencies were also increased in the range of 4.2-12.0 kHz for 65μm thick film sample, 4.1-9.0 kHz for 88μm thick film sample, and 4.2-9.0 kHz for 210μm sample. Effects of film thickness on the oscillator＇s frequency with respect to humidity were also investigated. This polymer humidity sensor controlled oscillator can be used for short-range and long-range remote systems at environmental monitoring and assessment of the humidity level.展开更多
文摘The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat transfer.Homogeneous–heterogeneous reaction and radiative effects have been further taken into account to reconnoiterproperties of heat transfer.Melting heat transfer and phenomenon of homogeneous–heterogeneous reaction have engrossed widespread utilization in purification of metals,welding process,electroslag melting,biochemical systems,catalysis and several industrial developments.Suitable transformations are utilized to attain a scheme of ordinary differential equations possessing exceedingly nonlinear nature.Homotopic process is employed to develop convergent solutions of the resulting problem.Discussion regarding velocity,thermal field and concentration distribution for several involved parameters is pivotal part.Graphical behaviors of skin friction coefficient and Nusselt number are also portrayed.Concentration of the reactants is found to depreciate as a result of strength of both heterogeneous and homogeneous reaction parameters.With existence of melting phenomenon,declining attitude of fluid temperature is observed for higher radiation parameter.
文摘Combined effects of Soret(thermal-diffusion) and Dufour(diffusion-thermo) in MHD stagnation point flow by a permeable stretching cylinder were studied. Analysis was examined in the presence of heat generation/absorption and chemical reaction. The laws of conservation of mass, momentum, energy and concentration are found to lead to the mathematical development of the problem. Suitable transformations were used to convert the nonlinear partial differential equations into the ordinary differential equations. The series solutions of boundary layer equations through momentum, energy and concentration equations were obtained.Convergence of the developed series solutions was discussed via plots and numerical values. The behaviors of different physical parameters on the velocity components, temperature and concentration were obtained. Numerical values of Nusselt number, skin friction and Sherwood number with different parameters were computed and analyzed. It is found that Dufour and Soret numbers result in the enhancement of temperature and concentration distributions, respectively.
文摘The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics effects.The processes of heat and mass transport incorporate the temperature-dependent binary chemical reaction with modified Arrhenius theory of activation energy function which is not yet disclosed for squeezing flow mechanism.The flow,heat and mass regime are exposed to be governed via dimensionless,highly non-linear,ordinary differential equations (ODEs) under no-slip walls boundary conditions.A well-tempered analytical convergent procedure is adopted for the solutions of boundary value problem.A detailed study is accounted through graphs in the form of flow velocity field,temperature and fluid concentration distributions for various emerging parameters of enormous interest.Skin-friction,Nusselt and Sherwood numbers have been acquired and disclosed through plots.The results indicate that fluid temperature follows an increasing trend with dominant dimensionless reaction rate σ and activation energy parameter E.However,an increment in σ and E parameters is found to decline in fluid concentration.The current study arises numerous engineering and industrial processes including polymer industry,compression and injection shaping,lubrication system,formation of paper sheets,thin fiber,molding of plastic sheets.In the area of chemical engineering,geothermal engineering,cooling of nuclear reacting,nuclear or chemical system,bimolecular reactions,biochemical process and electrically conducting polymeric flows can be controlled by utilizing magnetic fields.Motivated by such applications,the proposed study has been developed.
文摘The present study is carried out to see the thermal-diffusion(Dufour) and diffusion-thermo(Soret) effects on the mixed convection boundary layer flow of viscoelastic nanofluid flow over a vertical stretching surface in a porous medium. Optimal homotopy analysis method(OHAM) is best candidate to handle highly nonlinear system of differential equations obtained from boundary layer partial differential equations via appropriate transformations. Graphical illustrations depicting different physical arising parameters against velocity, temperature and concentration distributions with required discussion have also been added. Numerically calculated values of skin friction coefficient, local Nusselt and Sherwood numbers are given in the form of table and well argued. It is found that nanofluid velocity increases with increase in mixed convective and viscoelastic parameters but it decreases with the increasing values of porosity parameter. Also, it is observed that Dufour number has opposite behavior on temperature and concentration profiles.
文摘This article scrutinizes the features of viscous dissipation in the stagnation point ?ow past through a linearly stretched Riga wall by implementing Cattaneo-Christov heat ?ux model. Viscous dissipation is carried out in Cattaneo-Christov diffusion analysis for the ?rst time in this letter. As a result of Cattaneo-Christov model, some extra terms of viscous dissipation are appeared in the energy equation. These extra terms of viscous dissipation are missing in the literature. On the utilization of suitable transformations, the equations governing the problem are reduced under the boundary layer approximation into the non-linear and dimensionless ordinary differential equations. Convergent approach is utilized to solve the dimensionless governing equations. The solution thus acquired is used to highlight the effects of emerging parameters on velocity distribution and ?uid's temperature through the graphs. Features of the drag force(or skin friction co-e?cient) are graphically interpreted. It is noticed that the presence of modi?ed Hartman number helps to reduce the ?uid's temperature but enhances the velocity pro?le. Further an enlargement in the value of thermal time relaxation parameter helps to decrease the temperature distribution.
文摘This letter describes the characteristics of homogeneous-heterogeneous re- action in the boundary layer flow of a Jeffrey fluid due to an impermeable horizontal stretching sheet. An analysis is carried out through the similar values of reactant and auto catalyst diffusion coefficients. Heat released by the reaction is not accounted. The exact solution for the flow of the Jeffrey fluid is constructed. The series solution for the concentration equation is derived. The velocity and concentration fields reflecting the impact of interesting parameters are plotted and examined.
文摘A thin film of blended poly-N-epoxypropylcarbazole（PEPC）（25 wt.%）,nickel phthalocyanine（NiPc）（50 wt.%） and ZnO nano-powder（25 wt.%） in benzene（5 wt.%） was spin-coated on a glass substrate with silver electrodes to produce a surface-type Ag/PEPC/NiPc/ZnO/Ag capacitive and resistive sensor.Sensors with two different PEPC/NiPc/ZnO film thicknesses（330 and 400 nm） were fabricated and compared.The effects of humidity on capacitance and resistance of the Ag/PEPC/NiPc/ZnO/Ag sensors were investigated at two frequencies of the applied voltage：120 Hz and 1 kHz.It was observed that at 120 Hz under humidity of up to 95%RH the capacitance of the sensors increased by 540 times and resistance decreased by 450 times with respect to humidity conditions of 50%RH. It was found that the sensor with a thinner semiconducting film（330 nm） was more sensitive than the sensor with a thicker film（400 nm）.The sensitivity was improved when the sensor was used at a lower frequency as compared with a high frequency.It is assumed that the humidity response of the sensors is associated with absorption of water vapors and doping of water molecules in the semiconductor blend layer.This had been proven by simulation of the capacitance-humidity relationship.
基金GIK Institute of Engineering Sciences and Technology for the support extended to this work
文摘Au/cellulose-PEPC/Au surface-type humidity sensors were fabricated by drop-casting cellulose and poly-N-epoxypropylcarbazole （PEPC） blend thin films. A blend of 2wt% of each cellulose and PEPC in benzol was used for the deposition of humidity sensing films. Blend films were deposited on glass substrates with preliminary deposited surface-type gold electrodes. Films of different thicknesses of cellulose and PEPC composite were deposited by drop-casting technique. A change in electrical resistance and capacitance of the fabricated devices was observed by increasing the relative humidity in the range of 0-95% RH. It was observed that the capacitances of the sensors increase, while their resistances decrease with increasing the relative humidity. The sensors were connected to op-amp square wave oscillators. It was observed that with increasing the relative humidity, the oscillator＇s frequencies were also increased in the range of 4.2-12.0 kHz for 65μm thick film sample, 4.1-9.0 kHz for 88μm thick film sample, and 4.2-9.0 kHz for 210μm sample. Effects of film thickness on the oscillator＇s frequency with respect to humidity were also investigated. This polymer humidity sensor controlled oscillator can be used for short-range and long-range remote systems at environmental monitoring and assessment of the humidity level.
