Enhancement in heat transfer due to hybrid nanoparticles in MHD flow of Brinkman-type fluids using Caputo fractional derivatives.

The flow of fluid through porous media is of great importance in industry and other physical situations, Darcy's law is one of the most useful laws to describe such situation, however, the flows through a dense swarm of particles or through a very high porous media cannot be elaborated by this law. To overcome this difficulty, Brinkman proposed a new idea of Brinkman-type fluid in highly porous media. In this study, the Brinkman-type fluid flow is analyzed with hybrid nanoparticles (a hybridized mixture of clay and alumina), suspended in water taken as a base fluid under the effect of an applied magnetic field. The fluid motion is taken inside a vertical channel with heated walls. Free convection is induced due to buoyancy. The momentum and energy equations are written in dimensionless form using the non-dimensional variables. The energy equation is modified to fractional differential equations using the generalized Fourier's law and the Caputo fractional derivatives. The fractional model is solved using the Laplace and Fourier transformation. Variations in velocity and temperature are shown for various fractional parameter values, as well as charts for the classical model. For the volume fractions of nanoparticles, the temperature distribution increases, with maximum values of hybrid nanoparticles with the highest specified volume fractions. Moreover, due to hybrid nanoparticles, the rate of heat transfer is intensified.

Randomized trial of high-dose rectal diclofenac suppository and epinephrine spray on duodenal papilla for prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis.

BACKGROUND AND AIMS: High-dose rectal diclofenac suppository and epinephrine spray on duodenal papilla during endoscopic retrograde cholangiopancreatography (ERCP) may reduce the incidence of post-ERCP pancreatitis. We performed randomized trial to compare the effect of combination of rectal diclofenac and epinephrine spray on papilla (group A) vs. combination of rectal diclofenac with saline spray (group B) for prevention of post-ERCP pancreatitis. METHODS: We performed a double-blind trial at tertiary care center from April 2018 to May 2020 on 882 patients with naive papilla undergoing ERCP. The patients were randomly assigned to groups, A (n=437) or B (n=445). All patients received a single dose of rectal diclofenac 100 mg within 30 minutes before ERCP; 20 mL of diluted epinephrine 0.02% (group A) or saline (group B) was then sprayed on the duodenal papilla at the end of ERCP. The primary outcome was to compare incidence of post-ERCP pancreatitis (PEP) in two groups. RESULTS: The groups had similar baseline characteristics. PEP developed in 28 patients in group A (6.4%) and 35 patients in group B (7.9%) (relative risk, 1.1; 95% CI, 0.87-1.39; p=0.401). CONCLUSION: Our study showed that addition of epinephrine spray on duodenal papilla did not reduce the risk of post-ERCP pancreatitis. There is need for further studies to evaluate the role of different concentrations of epinephrine spray on papilla for prevention of post-ERCP pancreatitis. TRIAL REGISTRATION: Clinical Trials Registry- India (CTRI/2018/04/013396).

Fractional model for MHD flow of Casson fluid with cadmium telluride nanoparticles using the generalized Fourier's law.

The present work used fractional model of Casson fluid by utilizing a generalized Fourier's Law to construct Caputo Fractional model. A porous medium containing nanofluid flowing in a channel is considered with free convection and electrical conduction. A novel transformation is applied for energy equation and then solved by using integral transforms, combinedly, the Fourier and Laplace transformations. The results are shown in form of Mittag-Leffler function. The influence of physical parameters have been presented in graphs and values in tables are discussed in this work. The results reveal that heat transfer increases with increasing values of the volume fraction of nanoparticles, while the velocity of the nanofluid decreases with the increasing values of volume fraction of these particles.

A Report On Fluctuating Free Convection Flow Of Heat Absorbing Viscoelastic Dusty Fluid Past In A Horizontal Channel With MHD Effect.

The free convective unsteady fluctuating, MHD flow of electrically conducting viscoelastic dusty fluid in a channel-driven with the impact of oscillating pressure gradient and the motion of the upper plate has been studied in this article. The noteworthy heat generation/absorption has also taken into account, the heat generation established the mechanism of heat transfer by both the momentum of fluid and the motion of dust particle and absorption of heat by the dust particle is because of conduction. The coupled governing partial differential equations are reduced to the ordinary differential equation through the assumed periodic solutions. Analytical solutions for the velocity of the fluid as well as the velocity of dust particles and for energy equation of the fluid and for dust particles are obtained by using Poincare-Light Hill Perturbation Technique. The influence of various parameters of interest is discussed on the velocity and temperature profiles of the fluid and particles. The evolution of fluid-phase and dusty-phase with dual behavior of the magnetic parameter for both boundary layer and free stream velocities has been discussed. The boundary layer velocity decreased with an increase in magnetic parameter, while at the free stream flow, the result is quite opposite. The above result of magnetic field is worthwhile and can be used to control the boundary layer thickness. The current work also concludes that by increasing the Peclet number and concentration of the dust particles retards the boundary layer velocity. Furthermore, various physical parameters like coefficient of heat absorption, concentration of the dust particles, peclet number, magnetic parameter, and temperature relaxation time parameter retard the motion of dusty-phase, while Grashof number enhances the flow of dusty-phase. Other properties of fluid, which have great importance for engineers are, the rate of heat transfer and skin friction. It is shown in Table 1 that by increasing the value of Peclet number from 1 to 2 it increases the rate of heat transfer from 1.3263 to 1.3387. Furthermore, Table 2 shows that by increasing the concentration parameter from 2 to 4 the skin friction increases from 2.3872 to 4.7799.

Effects of Different Shaped Nanoparticles on the Performance of Engine-Oil and Kerosene-Oil: A generalized Brinkman-Type Fluid model with Non-Singular Kernel.

In the modern era, diathermic oils have been gotten the great attention from researchers due to its notable and momentous applications in engineering, mechanics and in the industrial field. The aim of this paper is to model the problem to augment the heat transfer rate of diathermic oils, specifically, Engine-oil (EO) and Kerosene-oil (KO) are taken. The present work is dedicated to examine the shape impacts of molybdenum-disulfide (MoS2) nanoparticles in the free convection magnetohydrodynamic (MHD) flow of Brinkman-type nanofluid in a rotating frame. The problem is modeled in terms of partial differential equations with oscillatory boundary conditions. The integer-order model is transformed to fractional-order model in time (Caputo-Fabrizio). The exact solutions are obtained using the Laplace transform technique. Figures are drawn to compare the different non-spherically shaped molybdenum-disulfide nanoparticles on secondary and primary velocities. The Nusselt number is computed in the tabular form and discussed in detail. It is worth noting that platelet and blade shape of MoS2 nanoparticle has more tendency to improve the heat transfer rate of both fluids as compared to nanoparticles with brick and cylinder shapes. It is also shown that the rate of heat transfer enhances 13.51% by adding MoS2 in engine oil which improved its lubrication properties.