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1.
Nanoscale Adv ; 5(22): 6135-6147, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37941941

RESUMO

Objective: Nanoliquid flows are widely utilized in industrial, petroleum, engineering, and pharmaceutical applications including electric cooling, drug delivery, nuclear reactor cooling, solar collectors, heat exchangers, magnetohydrodynamic power generators, aerospace, porous media, thermal storage systems, and many others. Darcy-Forchheimer magnetized hybrid nanoliquid subjected to a stretchable cylinder was addressed, and the Cattaneo-Christov heat flux analysis was considered. Herein, disulfido (dithioxo) molybdenum (MoS4) and cobalt ferrite (CoFe2O4) were considered as nanoparticles, and engine oil as a conventional liquid. The thermal relationship of heat generation and radiation was discussed, and the influence of the entropy rate was addressed. Methodology: Governing expressions were transformed into dimensionless forms. Simulation by the ND-solve technique was implemented. Conclusions: Features for the entropy rate, liquid flow, and temperature against emerging variables for nanoliquid (MoS4/engine oil) and hybrid nanoliquid (MoS4 + CoFe2O4/engine oil) were explored. The numerical results of the coefficient of skin friction and thermal transport rate for nanoliquid (MoS4/engine oil) and hybrid nanoliquid (MoS4 + CoFe2O4/engine oil) were examined. Reduction in velocity clearly occurred through a magnetic field, whereas the reverse impact held for the entropy rate. The thermal field and entropy rate against the curvature parameter were enhanced. A decrease in liquid flow occurred for higher porosity variables. An enhancement in the entropy rate was witnessed for radiation and porosity parameters. Higher radiation and thermal relaxation time variables resulted in enhancement of the thermal transport rate.

2.
Nanoscale Adv ; 5(22): 6249-6261, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37941948

RESUMO

Nanomaterials are quite promising in electronic cooling systems, heat exchangers, engine lubricants, brake liquids, shock absorbers, radiators, etc. Therefore, the study of heat transfer characteristics on the flow of trihybrid nanofluids on an exponentially stretched curved surface is developed. Purpose: In this study, trihybrid nanofluid is taken into consideration, which is composed of Fe3O4, Ag and Cu as nanoparticles and water as the basefluid. Heat generation and magnetic field impacts are addressed. Based on these assumptions, the governing partial differential equations were reduced to a favorable set of ordinary differential equations using adequate transformations. Formulation: The highly nonlinear coupled system of equations was numerically solved using the shooting method with the Runge-Kutta-Fehlberg technique. Findings: Trihybrid nanofluids improve the thermal performance of fluid when compared with other fluids such as hybrid nanofluids, nanofluids, and basefluids. The trihybrid nanofluid is efficient in heat transfer phenomenon and has a significant impact on the overall performance of a system, including cooling systems, heat exchangers, electronics, and many industrial processes. Graphical representation for the physical variables of the fluid velocity and temperature is discussed. The local Nusselt number and skin friction coefficient are computed and analyzed. A magnetic field decreases the velocity but escalates the temperature. The Nusselt number decreases for larger solid volume fractions. Novelty: The Tiwari and Das model for hybrid nanofluid extended for trihybrid nanoparticles has not been investigated previously. Heat transfer examination on the flow of trihybrid nanomaterials on exponentially curved stretching sheets considering magnetism force and heat generation consequence has not yet been studied.

3.
Nanoscale Adv ; 5(18): 4863-4872, 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37705799

RESUMO

Here, the magnetohydrodynamic bioconvective flow of a non-Newtonian nanomaterial over a stretched sheet is scrutinized. The characteristics of convective conditions are analyzed. Irreversibility analysis in the presence of gyrotactic micro-organisms is discussed. Energy expression is assisted with thermal radiation, heat generation and ohmic heating. Buongiorno's model is employed to discuss the characteristics of the nanoliquid through thermophoresis and random diffusions. Nonlinear expressions of the given model are transformed through adequate transformations. The obtained expressions have been computed by the Newton built in-shooting technique. Results of influential variables for velocity, concentration, microorganism field, temperature and entropy rate are graphically studied. Clearly, velocity reduction is witnessed for the bioconvection Rayleigh number and magnetic variable. A higher heat generation variable leads to augmentation of temperature. An increase in the magnetic variable results in entropy and temperature enhancement. A higher Peclet number results in microorganism field reduction. Temperature distribution rises for radiation and the thermal Biot number. A higher solutal Biot number intensifies the concentration. The entropy rate for radiation and diffusion variables is enhanced.

4.
Heliyon ; 9(6): e16393, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37332977

RESUMO

This article addresses unsteady nanofluid flow over a cone with MHD and mixed convection effects. Effects of variable viscosity and viscous dissipation are also considered. The resulting system of equations is tackled through the Homotopy Analysis Method (HAM). The impact of different influential variables on skin friction coefficient, heat and mass flux are discovered through numerical tables and graphs. It is noted that the surface drag force in x and y directions increases against the buoyancy force parameter. Also, it is observed that the tangential and azimuthal velocity decrease against the variable viscosity parameter. Furthermore, the temperature of fluid is observed to decay against the unsteady parameter but it increases against the Eckert number.

5.
Heliyon ; 9(5): e16192, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37229170

RESUMO

In this study, an analysis was performed to investigate the thermal and mass transport of radiative flow of a third-grade nanofluid with magnetohydrodynamic. The analysis concerns two-dimensional flow around an infinite disk. Heat transport is studied via heat generation/absorption, thermal radiation and Joule heating. Chemical reaction with activation energy is also considered. The nanofluid characteristics, including Brownian motion and thermophoretic diffusion, are explored via the Buongiorno model. Entropy analysis is also conducted. Moreover, the surface tension is assumed to be a linear function of concentration and temperature. Through adequate dimensionless variables, governed PDEs are non-dimensionlized and then tackled by ND-solve (a numerical method in Mathematica) for solutions purposes. Entropy generation, concentration, velocity, Bejan number and temperature are plotted as functions of the involved physical parameters. It is noticed that higher Marangoni number intensify velocity however it causes a decrease in the temperature. Entropy rate and Bejan number boost for large value of diffusion parameter.

6.
Comput Biol Med ; 155: 106699, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36857941

RESUMO

Current analysis highlights the aspects of different nanoparticles in peristalsis with entropy generation. Mathematical equations of considered problem are modelled via conservation laws for mass, momentum and energy. Such equations contain variable viscosity, nonlinear thermal radiation, viscous dissipation, heat generation/absorption and mixed convection aspects. Boundary conditions comprise the second order velocity and first order thermal slip effects. Entropy expression is obtained by utilization thermodynamics. Simplified and dimensionless forms of the considered conservative laws are obtained through lubrication technique. Resulting system of equations subject to the considered boundary conditions is solved numerically via built-in shooting procedure in Mathematica. Such numerical procedure is very suitable to obtain numerical results directly and fastly in the form of graphs. Further all the considered flow quantities are discussed graphically for the significant parameters of interest in detail. Both velocity and temperature are decreasing against large volume fraction parameter. Increasing temperature dependent viscosity effects decrease the entropy and enhance the Bejan number.


Assuntos
Modelos Teóricos , Nanoestruturas , Entropia , Viscosidade , Peristaltismo
7.
Comput Methods Programs Biomed ; 196: 105474, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32659644

RESUMO

Chilling systems are important in the improved technological thermal mechanisms which are considered continuously in passive along with active heat-transference improvement procedures. Engineers recommended several approaches to upsurge heat transference of thermal structures. The pulsating flow, corrugated tube, magnetic field aspect and nanoliquids are the heat-transference improvement procedures delved continuously. In present research work, we addressed the heat-transference characteristics of non-Newtonian (Oldroyd-B) liquid towards heated stratified surface. Thermally radiative laminar flow is modeled. In addition, we accounted Buongiorno's nanoliquid model which includes Brownian along with thermophoretic diffusions. Modeling is further based on heat source, magnetohydrodynamics, dual stratification, thermal radiation and convective conditions. Mathematical system is simplified through boundary-layer idea. Similarity variables are reported with the aim to simplify complex mathematical system. Homotopy algorithm yields convergent results of non-dimensional expressions. Our study unveils diminution of thermal along with solutal fields when stratification factors are increased.


Assuntos
Hidrodinâmica , Aves Canoras , Algoritmos , Animais , Difusão , Campos Magnéticos
8.
Comput Methods Programs Biomed ; 196: 105564, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535331

RESUMO

This research article proposes an improved Fourier law of heat conduction (Cattaneo-Christov) in presence of heat source/sink. The heat transport characteristics are modeled for mixed convective stagnation point flow by a Riga plate. Flow is generated due to linear stretching velocity. The partial differential system is changed to ordinary differential system through implementing appropriate transformations. Series solutions are developed through semi-analytical method called as homotopy analysis method. Present research article is related to the improved Fourier law of heat conduction (Cattaneo-Christov) over a linear stretchable surface of Riga plate when fluid saturates porous space. The main outcomes of present communication are summarized as: (i) velocity of material particles decreases subject to larger inverse Darcy-number while it enhances via velocity ratio and magnetic parameters (ii) temperature distribution as well as layer thickness enhance for higher estimations of Eckert number and heat source parameter while it decays against Prandtl number (iii) skin friction coefficient decreases through higher values of inverse Darcy number and mixed convection parameter.


Assuntos
Temperatura Alta , Modelos Teóricos , Convecção , Condutividade Térmica , Viscosidade
9.
Comput Methods Programs Biomed ; 190: 105252, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32059157

RESUMO

In this published paper, a mathematical modeling has been conducted for the peristaltic transport in flow of hybrid nanofluid between rotating channel in the presence of nonlinear thermal radiation, slip effects and entropy generation. This corrigendum correct the flow geometry, figures captions and plots "Transport of hybrid type nanomaterials in peristaltic activity of viscous fluid considering nonlinear radiation, entropy optimization and slip effects" [Computer Methods and Programs in Biomedicine 184 (2020) 105,086] where these mistake are occurred during production process and therefore, some captions are shuffled. The difference in the captions and plots however does not affect the authenticity and mathematical validity of the problem in purpose of this published research article is to investigate the peristaltic transport in flow of hybrid nanofluid between rotating channel subject to nonlinear thermal radiation, slip effects and entropy generation. However, the flow geometry and the captions and plots should be arranged.


Assuntos
Algoritmos , Hidrodinâmica , Nanoestruturas , Gráficos por Computador , Entropia , Viscosidade
10.
Comput Methods Programs Biomed ; 183: 105051, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31526945

RESUMO

BACKGROUND: A newly developed approach in the field of nanotechnology for solving problems and collection of information is the use of nanoparticles. This idea has been further utilized in a better way in pharmaceutical industries. By using nanotechnology, the field of pharmaceutical science has been modernized and redeveloped. The use of nanotechnology in such industries has convinced the scientist to obtain more economical and easier applications. Therefore, with such effectiveness in mind, a theoretical study has been conducted to examine the effects of nonlinear radiative heat flux and magnetohydrodynamics for nanomaterial flow of Williamson fluid over a convectively heated stretchable surface. Brownian diffusion is utilized in mathematical modeling. Furthermore, heat source/sink, viscous dissipation and nonlinear radiative heat flux are examined. Convective boundary condition is implemented. Salient effects of chemical reaction and Arrhenius activation energy in mass transfer are considered. Total entropy rate is obtained through implementation of thermodynamics second law. METHODS: The nonlinear PDEs are reduced into ordinary ones by appropriate similarity transformations. A semi-analytical technique i.e., homotopy method is implemented to obtain the convergent series solutions. RESULTS: The obtained results indicate that the velocity of fluid particles increases versus higher fluid parameter. Schmidt number and activation energy variable have opposite effect on concentration. Entropy rate grows up with fluid parameter and Brinkman and Biot numbers while opposite trend is seen for Bejan number. CONCLUSIONS: Velocity of the material particles declines through larger estimations of magnetic variable while it upsurges for higher fluid parameter. Thermal distribution shows similar impact for radiative and magnetic variables. Mass concentration decreases against chemical reaction parameter while it increases via activation energy variable. Entropy and Bejan numbers show opposite impacts versus Brinkman number. Skin friction coefficient increases through larger Weissenberg number.


Assuntos
Temperatura Alta , Nanopartículas/química , Nanotecnologia/tendências , Algoritmos , Difusão , Entropia , Fricção , Magnetismo , Teste de Materiais , Modelos Teóricos , Nanoestruturas/química , Viscosidade
11.
Comput Methods Programs Biomed ; 183: 105061, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31539717

RESUMO

BACKGROUND: Nanofluids have innovative characteristics that make them potentially beneficial in numerous applications in heat and mass transports like fuel cells, hybrid-powered engines, microelectronics, pharmaceutical processes, domestic refrigerator, engine cooling, heat exchanger, chiller and in boiler flue gas temperature decay. Nanomaterial increased the coefficient of heat transport and thermal performance compared to continuous phase liquid. Having such significance in mind, the nanofluid flow of second grade material over a convectively heated surface is examined here. Nano-fluid is electrically conducting. Energy expression is studied through Joule heating, heat source/sink and dissipation. In addition, thermophoresis and Brownian diffusion are investigated. Physical aspects of entropy optimization in nanomaterials with cubic autocatalysis chemical reaction are accounted. Through second law of thermodynamics the total entropy generation rate is computed. METHODS: The nonlinear governing PDE's are transformed to ordinary ones through transformations. Total residual error is calculated for momentum, energy and concentration equations using optimal homotopy analysis method (OHAM). RESULTS: Behaviors of different variables on velocity, Bejan number, concentration, temperature and entropy optimization are examined via graphs. Local skin friction coefficient (Cfx) and gradient of temperature (Nux)are examined graphically. Comparison between the recent and previous result is given. Temperature and velocity are enhanced significantly versus (λ1). Entropy generation rate boosts up for magnetic parameter and Brinkman number. CONCLUSIONS: The obtained outcomes show that velocity is higher via mixed convective variable. Temperature boosts up in presence of higher magnetic parameter, thermophoretic paraemter, Brinkman number and second grade parameter while Biot number decays. Concentration has increasing behavior via larger Brownian and homogeneous and heterogeneous parameters. Entropy rate and Bejan number have similar impact through diffusion parameters with respect to both homogeneous and heterogeneous reactions variables.


Assuntos
Nanoestruturas/química , Nanotecnologia/métodos , Algoritmos , Catálise , Simulação por Computador , Entropia , Temperatura Alta , Hidrodinâmica , Magnetismo , Teste de Materiais , Modelos Teóricos , Resistência ao Cisalhamento , Estresse Mecânico , Propriedades de Superfície
12.
Comput Methods Programs Biomed ; 187: 105247, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31812885

RESUMO

Background Magnetohydrodynamic (MHD) stagnation point flow of Oldroyd-B nanoliquid is discussed in presence of Cattaneo-Christov mass and heat fluxes. Impacts of Brownian motion and thermophoresis are discussed. Convergent solution for nonlinear analysis are organized for velocity, temperature and concentration. Method Average residual error is calculated with the help of optimal homotopy analysis method (OHAM). Results Prominent features of interesting parameters on concentration, velocity and temperature are scrutinized. Velocity field has reverse trend for Deborah number against retardation and relaxation times. Temperature and concentration have similar results versus thermophoresis parameter. Conclusions: 1: Velocity has opposite impact for Deborah number for relaxation and retardation time. 2: Velocity boosts up for higher ratio parameter. 3: Velocity against magnetic parameter is decreased. 4: Thermal upsurges versus thermal relaxation time parameter. 5: Outcomes of thermophoretic parameter and Brownian motion parameter on temperature are quantitatively similar. 6: Concentration boosts up via Brownian parameter. 7: Concentration have similar characteristics for both Prandtl number and thermophoretic parameter.


Assuntos
Nanoestruturas/química , Nanotecnologia/métodos , Pele/patologia , Algoritmos , Fenômenos Biomecânicos , Campos Eletromagnéticos , Análise de Fourier , Fricção , Temperatura Alta , Humanos , Campos Magnéticos , Modelos Teóricos , Fenômenos Fisiológicos da Pele , Estresse Mecânico , Viscosidade
13.
Comput Methods Programs Biomed ; 187: 105255, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31821977

RESUMO

Here we discuss the analysis of irreversibility in electrical magnetohydrodynamic convective flow of nanomaterials over a stretchable surface. Energy equation deliberated through Joule heating, dissipation and heat source/sink. Furthermore features chemical reaction is also considered. Total entropy optimization is calculated. Salient features of thermophoresis effect and random motion of particles are studied. Nonlinear couple equations are converted to ordinary system by using the transformation. The obtained system are elucidated through ND solve technique. Salient features of pertinent variables on entropy optimization, velocity, Bejan number, concentration and temperature are discussed. Nusselt number, gradient of concentration and surface drag force are computationally calculated. Velocity and temperature show opposite behaviors via magnetic parameter. Electric and magnetic field parameters on entropy optimization have opposite results.


Assuntos
Eletricidade , Campos Magnéticos , Nanoestruturas/química , Algoritmos , Temperatura Alta , Teste de Materiais , Modelos Teóricos , Nanotecnologia/métodos , Estresse Mecânico , Termodinâmica
14.
Comput Methods Programs Biomed ; 184: 105104, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31627145

RESUMO

BACKGROUND: This manuscript elaborates the three-dimensional radiated Darcy-Forchheimer viscous liquid flow subject to permeable stretched surface. The stretched surface is nonlinear and saturated via Darcy-Forchheimer medium. Energy expression is derived through implementation of first of thermodynamics and discussed subject to convective condition and nonlinear heat flux. Mixed convection is also considered. METHOD: The governing systems of nonlinear equations are tackled numerically by Shooting method. RESULTS: Graphical results are depicted and examined with different values of non-dimensional parameters for velocity and energy equations respectively. Drag force and Nusselt number are computationally computed and analyzed through Tables. CONCLUSIONS: It is concluded from the derived outcomes that both component of velocity decay against higher values of local inertia coefficient and inverse Darcy number variables. For suction case both velocities increases while opposite trend is observed for injection case. Temperature profile has an increasing impact for higher values of Radiation, and Biot number while opposite result is seen for injection. Drag force or skin friction declines via larger injection variable. Nusselt number increases for radiation variable.


Assuntos
Simulação por Computador , Dinâmica não Linear , Permeabilidade , Porosidade , Reologia , Termodinâmica , Viscosidade
15.
Comput Methods Programs Biomed ; 184: 105105, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31627151

RESUMO

BACKGROUND: CNTs (Carbon nanotubes) being allotropes of carbon, made of graphene and diameters of single and multi-walls carbon nanotubes are typically 0.8 to 2 nm and 5 to 20 mn, although diameter of MWCNTs can exceed 100 nm. Carbon nanotubes lengths range from less than 100 nm to 0.5 m. Their impressive structural, electronic and mechanical attributes subject to their small size and mass, their high electrical and thermal conductivities, and their strong mechanical potency. CNTs based materials are successfully applied in medicine and pharmacy subject to their huge surface area that is proficient of conjugating or adsorbing with a wide variety of genes, drugs, antibodies, vaccines and biosensors etc. Therefore, we have presented a theoretical study about mathematical modeling of CNTs based viscous material flow between two rotating disks. Both types of nanotubes i.e., SWCNTs and MWCNTs are considered. Xue model is used for the mathematical modeling. Fluid flow is due to rotating disks. Main focus here is given to probable error and statistical declaration. Entropy is calculated for both single and multi-walls nanotubes. METHOD: Nonlinear PDEs are first converted into ODEs and then computed for homotopy convergent solutions. RESULTS AND CONCLUSION: Statistical declaration and probable error for skin friction and Nusselt number are numerically computed and discussed through Tables. From obtained outcomes it is concluded that magnitude of skin friction increases at both disks surface for higher values of Reynolds number, lower stretching parameter and porosity parameter while it decays for both of disks versus larger rotation parameter. Nusselt number or heat transfer rate also enhances at both disks in the presence of radiation and Reynolds number while it decays against Eckert number.


Assuntos
Entropia , Nanoestruturas/química , Nanotubos de Carbono/química , Modelos Teóricos , Probabilidade , Reprodutibilidade dos Testes
16.
Comput Methods Programs Biomed ; 184: 105086, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31627153

RESUMO

BACKGROUND: In last few decades, a new class of working materials which comprises from two solid materials dispersed in a continuous phase liquid was established and deeply scrutinized. These materials are called hybrid nanomaterials. This research article aims to investigate entropy optimization in hybrid nanomaterial flow through a rotating peristaltic channel walls. Flow behavior is analyzed between the channels which is caused by propagation of sinusoidal waves. Viscosity of fluid is considered variable instead of constant characteristics. Fluid saturates through porous attributes of channel walls. Nonliear radiative flux and convective condition are considered. Slip conditions are imposed at the boundary of walls. METHODS: Built-in-Shooting technique is employed to obtain the numerical outcomes for the considered flow problem. RESULTS: Impacts of sundry variables on the entropy, temperature and velocity are scrutinized through different graphs. Numerical result presents that the axial velocity escalates with the inclusion of hybrid nanomaterial. The temperature of fluid enhances through higher estimations of hybrid nanoparticles. CONCLUSIONS: Here the flow behavior is discussed between the channels which are caused by propagation of sinusoidal waves with speed c. Entropy generation rate is minimum for variable viscosity and maximum for hybrid nanoparticles. Hybrid nanoparticles increase the temperature of fluid. Bejan number presents the similar impact for variable viscosity and thermal slip parameters. Temperature field decays through higher values of Brinkman number.


Assuntos
Entropia , Nanoestruturas , Reologia , Viscosidade , Simulação por Computador , Microfluídica , Temperatura
17.
Comput Methods Programs Biomed ; 184: 105111, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31622856

RESUMO

BACKGROUND: Nanomaterials have higher inspiration in the growth of pioneering heat transportation fluids and good efforts were made in this field during the recent year. Nowadays numerous scientists and researchers have focused their struggle on nanomaterials study. Nanoliquids have advanced properties which make them efficient in various applications including engine cooling, hybrid-power engine, pharmaceutical processes, refrigerator and vehicle thermal management etc. Therefore such implication in mind the entropy optimization in magnetohydrodynamic nanomaterials (TiO2 - GO) flow between two stretchable rotating disks is discussed here. Energy expression subject to Joule heating, thermal radiation and viscous dissipation is modeled. Entropy optimization rate is based upon thermodynamic second law. Here titanium dioxide (TiO2) and graphene oxide (GO) and water (H2O) are used as nanoliquids. Homogeneous and heterogeneous reactions have been accounted. METHODS: Transformation process reduced nonlinear PDE's to ordinary differential systems. Formulated systems are solved due to implementation of Newton built in shooting method. RESULTS: Salient behavior of influential variables on velocity, entropy optimization, temperature, Bejan number and concentration graphically illustrated for (TiO2 and GO). Surface drag force and gradient of temperature ((Cf1, Cf2) and (Nux1, Nux2)) are numerically computed for various interesting parameters at lower and upper disks respectively. Axial and radial velocities components boost up for larger (Re) but opposite is hold for tangential velocity. Entropy optimization and temperature are increased for higher Brinkman number (Br). CONCLUSIONS: A significant augmentation occurs in radial and axial velocities (f'(ξ) and f(ξ)) versus stretching parameter, while opposite is hold for tangential velocity (g(ξ)). For larger values of Reynold and Brinkman numbers the temperature increases. Temperature and entropy optimization have opposite effect for radiation parameter. Concentration has similar results for Reynold and Schmidt numbers. Entropy optimization and Bejan number for radiation parameter have similar outcome. Bejan number decays for Brinkman number.


Assuntos
Entropia , Grafite/química , Nanoestruturas/química , Titânio/química , Algoritmos , Hidrodinâmica , Temperatura , Termodinâmica , Água/química
18.
Comput Methods Programs Biomed ; 186: 105145, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31760305

RESUMO

BACKGROUND: Newtonian fluids can be categorized by a single coefficient of viscosity for specific temperature. This viscosity will change with temperature; it doesn't change with strain rate. Just a small group of liquids show such steady consistency. A fluid whose viscosity changes subject to relative flow velocity is called non-Newtonian liquids. Here we have summarized a result for the flow of Carreau-Yasuda fluid over a porous stretchable surface. Mixed convection is considered. Modeling of energy expression is performed subject to Soret and Dufour effects. METHOD: The nonlinear PDE's are changed to ODE's through suitable transformations and then solved for numerical solutions via Built-in shooting method (bvp4c). RESULTS: Variation of important variables is studied on the concentration, temperature and velocity fields. Tabular representation for study of skin friction and heat transfer rate is presented for important variables. Our results show that velocity decreases versus higher estimations of Weissenberg number, porosity parameter, buoyancy ratio and mixed convection parameter. Temperature decays via Weissenberg number and porosity parameter. Increase in concentration is noticed through higher Soret number and porosity parameter. Skin friction and heat transfer rate (Nusselt number) boosts versus larger porosity parameter and Prandtl number respectively while it decays against Weissenberg number and Dufour and Eckert number.


Assuntos
Modelos Teóricos , Viscosidade , Convecção , Porosidade , Temperatura
19.
Comput Methods Programs Biomed ; 183: 105093, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31586480

RESUMO

BACKGROUND: Study of nanofluids has been enormously increased for the last couple of years. Regardless of some irregularity in the revealed outcomes and lacking consistency, yet the mechanisms of heat transport have been emerged as highly efficient. In the continuation of nanomaterials research, the investigators and analyst have also attempted to utilize hybrid nanomaterial recently, which is designed by suspending unique nanomaterials (nanoparticles) either in mixture or composite structure. The theory of hybrid nanofluids can be further modified for heat transport and pressure drop attributes by trade-off between disadvantages and advantages of individual suspension, ascribed to great aspect ratio, better thermal system and synergistic impact of nanomaterials. Therefore, we have conducted a theoretical attempt on MHD entropy optimized viscous hybrid nanomaterial flow between two parallel plates. The boundaries of plates are fixed with velocity and thermal slip aspects. Chemical reaction with novel aspect of activation energy is accounted. Furthermore, thermal radiation, heat generation and Joule heating are examined. METHOD: The modeled system is numerically simulated through bvp4c technique. RESULTS: Behaviors of pertinent variables on the velocity, skin friction, temperature, Nusselt number, entropy generation rate and concentration are presented and discussed through different graphs. Temperature field decays against higher values of Eckert number and thermal slip variable. CONCLUSIONS: It is noticed that velocity of material particles increase against larger estimations of rotation parameter. Temperature declines versus larger Prandtl and Eckert numbers. Concentration decays when an enhancement is occurred in the Lewis number. Magnitude of surface drag force upsurges for rising values of Prandtl number and radiation parameter. Furthermore, magnitude of Nusselt number enhances through larger Eckert number, magnetic number and Prandtl number.


Assuntos
Entropia , Nanopartículas , Nanoestruturas , Algoritmos , Simulação por Computador , Cobre/química , Grafite/química , Temperatura Alta , Hidrodinâmica , Modelos Teóricos , Movimento , Rotação , Viscosidade , Água/química
20.
Diabet Med ; 37(4): 573-579, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31797434

RESUMO

Diabetic peripheral neuropathy in people with type 2 diabetes is poorly managed because of its insidious onset, delayed diagnosis and more complex aetiology resulting from the contribution of not only hyperglycaemia, but also ageing, hyperlipidaemia, hypertension and obesity. Because there is no US Food and Drug Adminstration-approved disease-modifying therapy for diabetic peripheral neuropathy, the key to ameliorating it in type 2 diabetes has to be through earlier diagnosis and timely multi-factorial risk factor reduction. The management of painful diabetic peripheral neuropathy also requires a detailed appraisal of the choice of therapy, taking into account efficacy, patient wishes, comorbidities, side effect profile and potential for abuse.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/terapia , Neuropatias Diabéticas/diagnóstico , Neuropatias Diabéticas/prevenção & controle , Diabetes Mellitus Tipo 2/diagnóstico , Neuropatias Diabéticas/etiologia , Neuropatias Diabéticas/terapia , Diagnóstico Precoce , Intervenção Médica Precoce/métodos , Intervenção Médica Precoce/normas , Humanos , Fatores de Risco , Comportamento de Redução do Risco
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