Enhancement of heat transfer in elastico-viscous fluid due to nanoparticles, where the fluid is impinging obliquely to the stretchable surface: A numerical study

This article addresses the two-dimensional oblique stagnation point flow of non-Newtonian fluid in the presence of nanoparticles. Constitutive equations of Walter-B fluid are employed in the mathematical development of the relevant problems. Mathematical formulation includes the Brownian motion and thermophoresis effects. The resulting nonlinear system of equations are analyzed through Chebyshev Spectral Newton Iterative Scheme (CSNIS). A comparative study of present results through tabular values has been made with the previous results in a limiting sense and an excellent agreement is noted. It is also found that in near stagnation point region, the heat transfer rate and mass diffusion flux decrease due to increase of thermophoresis effect. However, the heat transfer rate increases and mass diffusion flux decreases as the Brownian motion of the particles increases. The streamlines are drawn to capture the fluid motion

Radiation Effect on Mixed Convection Boundary Layer Flow of a Viscoelastic Fluid over a Horizontal Circular Cylinder with Constant Heat Flux

In the present article, radiation effect on mixed convection boundary layer flow of a viscoelastic fluid over a horizontal circular cylinder with constant heat flux has been numerically analyzed. The governing boundary layer equations are transformed to dimensionless nonlinear partial differential equations. The equations are solved numerically by using Keller-box method. The computed results are in excellent agreement with the previous studies. Skin friction coefficient and Nusselt number are emphasized specifically. These quantities are displayed against the curvature parameter. The effects of pertinent parameters involved in the problem namely effective Prandtl number and mixed convection parameter on skin friction coefficient and Nusselt number are shown through graphs and table. Boundary layer separation points are also calculated with and without radiation and a comparison is shown. The presence of radiation helps to decrease or increase the skin friction coefficient for the negative or positive values of the mixed convection parameter accordingly. The decrease in value of effective Prandtl number helps to increase the value of skin friction coefficient and Nusselt number for viscoelastic fluids

Total phenolic and flavonoid contents, cytotoxic, immunomodulatory and anti-inflammatory potential of whole plant of Astragalus creticus (Fabaceae)

Purpose: To determine total phenolic and flavonoid contents, as well as the cytotoxic, immunemodulatoryand anti-inflammatory potentials of the whole plant of Astragalus creticus (Fabaceae).Methods: Folin-Ciocalteu (FCR) method was used for determination of total phenolic and flavonoid contents of the methanol and dichloromethane extracts of Astragalus creticus. The cytotoxic potential of the extracts on 3T3 and HeLa cell lines were evaluated using MTT assay. Brine shrimp larvae mortality was determined by lethality bioassay, while inhibitory effects were determined on mouse fibroblast (3T3)and cervical cancer (HeLa) cell lines. In vitro immunomodulatory and in vivo anti-inflammatory effectswere assessed using reactive oxygen species (ROS) chemiluminescence and formalin-induced rat paw edema assays, respectively.Results: Dichloromethane extract had higher contents of phenolics (TPC = 324.75 ± 2.47 mg GAE/g) and flavonoids (TFC = 95.51 ± 0.82 QE/g) than the methanol extract (TPC = 79.82 ± 1.53 mg GAE/g, TFC = 56.11 ± 0.93 QE/g). The dichloromethane extract exhibited high cytotoxic andimmunomodulatory potentials, with 76.66 % mortality in brine shrimp lethality bioassay and 83.9 % inhibition (IC50 = 18.0 ± 1.1 μg/mL) in chemiluminescence assay. The extract also resulted in 22 and 13 % inhibition of viability of HeLa and 3T3 cells, respectively, while the methanol extract produced 13 % inhibition of both cell lines. The methanol extract produced very significant anti-inflammatory activity,with a maximum of 49 % inhibition of paw edema at a dose of 160 mg/kg (p < 0.01).Conclusion: These results suggest that the dichloromethane and methanol extracts of Astragalus creticus (Fabaceae) exert cytotoxic, immunomodulatory and anti-inflammatory effects. These findings provide scientific validation for the traditional medicinal use of the Astragalus genus

Optimization of blade profiles for a coaxial drone

In the civil market, an increase in the demand for drone technology has given rise to rotor blade design. Much research has to undergo to enhance the efficiency of propellers. In this research, we want to improve the propeller design efficiency in terms of flight endurance. The main goal is in the variation of axial separation by using computational fluid dynamics in OpenFOAM. We found that the variation of distance between two propellers has improved overall efficiency significantly during computational analysis. At the lowest separation, the interference disturbance created by the lower propeller affects the upper propeller performance by lowering total thrust. However, if we increase the distance, the lower propeller faces the downwash created by the upper propeller resulting in the efficiency loss of the lower one. One can increase or decrease the axial separation, but the overall efficiency would remain the same. Hence, it has been found that at 0.65z/R, we have the maximum efficiency

Optimization of blade profiles for a coaxial drone

In the civil market, an increase in the demand for drone technology has given rise to rotor blade design. Much research has to undergo to enhance the efficiency of propellers. In this research, we want to improve the propeller design efficiency in terms of flight endurance. The main goal is in the variation of axial separation by using computational fluid dynamics in OpenFOAM. We found that the variation of distance between two propellers has improved overall efficiency significantly during computational analysis. At the lowest separation, the interference disturbance created by the lower propeller affects the upper propeller performance by lowering total thrust. However, if we increase the distance, the lower propeller faces the downwash created by the upper propeller resulting in the efficiency loss of the lower one. One can increase or decrease the axial separation, but the overall efficiency would remain the same. Hence, it has been found that at 0.65z/R, we have the maximum efficiency