Mixed convection flow in vertical channel with boundary conditions of third kind in presence of heat source/sink

The effects of viscous dissipation and heat source/sink on fully developed mixed convection for the laminar flow in a parallel-plate vertical channel are investigated.The plate exchanges heat with an external fluid.Both conditions of equal and different reference temperatures of the external fluid are considered.First,the simple cases of the negligible Brinkman number or the negligible Grashof number are solved analytically.Then,the combined effects of buoyancy forces and viscous dissipation in the presence of heat source/sink are analyzed by a perturbation series method valid for small values of the perturbation parameter.To relax the conditions on the perturbation parameter,the velocity and temperature fields are solved by using the Runge-Kutta fourth-order method with the shooting technique.The velocity,temperature,skin friction,and Nusselt numbers at the plates are discussed numerically and presented through graphs.     

Simultaneous determination of olmesartan medoxomil and irbesartan and hydrochlorothiazide in pharmaceutical formulations and human serum using high performance liquid chromatography

 A simple, selective, sensitive, precise, simultaneous high performance liquid chromatographic analysis of serum samples and commercial tablet formulation containing hydrochlorothiazide, olmesartan medoxomil and irbesartan are reported. Good chromatographic separation was achieved using a μ-Bondapak, C18 column (15 cm×4.6 mm, 5 μm), and a mobile phase consisting of acetonitrile-0.2% acetic acid aqueous solution (50∶50, v/v) at a flow rate of 1.0 mL/min. The ultraviolet detector was set at a wavelength of 260 nm. Hydrochlorothiazide, olmesartan medoxomil, and irbesartan were eluted at 1.2, 3.8, and 4.4 min, respectively. No extraneous materials were found to interfere. The method uses protein precipitation with acetonitrile for the preparation of serum sample. The linear ranges for hydrochlorothiazide, olmesartan medoxomil, and irbesartan were 6.25-18.75, 20-60, and 75-225 ng/mL, respectively. The recoveries of hydrochlorothiazide, olmesartan medoxomil, and irbesartan in spiked samples were all greater than 98%, and their relative standard deviations were less than 2.0%. The limits of detection were 1, 2, and 2 ng/mL for hydrochlorothiazide, olmesartan medoxomil, and irbesartan, respectively, and the limits of quantification were 3 ng/mL, which allow their determination at the expected serum concentration levels.     

Non-axisymmetric Homann MHD stagnation point flow of Al_2O_3-Cu/water hybrid nanofluid with shape factor impact

The heat transfer of Homann flow in the stagnation region of the Al_2 O_3-Cu/water hybrid nanofluid is investigated by adopting the Tiwari-Das model over a cylindrical disk.The effects of the nanoparticle shape,the viscous dissipation,and the nonlinear radiation are considered.The governing equations are obtained by using similarity transformations,and the numerical outcomes for the flow and the temperature field are noted by bvp4 c on MATLAB.The numerical solutions of the flow field are compared with the asymptotic behaviors of large shear-to-strain-rate ratio.The effects of variations of parameters involved are inspected for both nanofluid and hybrid nanofluid flows,temperature profiles,local Nusselt numbers,and skin frictions.It is concluded that the velocity and temperature fields in the hybrid nanophase function more rapidly than those in the nanofluid phase.