Soret and Dufour effects on mixed convection in a non-Darcy porous medium saturated with micropolar fluid

In this paper, the Soret and Dufour effects on the steady, laminar mixed convection heat and mass transfer along a semi-infinite vertical plate embedded in a non-Darcy porous medium saturated with micropolar fluid are studied. The governing partial differential equations are transformed into ordinary differential equations. The local similarity solutions of the transformed dimensionless equations for the flow, microrotation, heat and mass transfer characteristics are evaluated using Keller-box method. Numerical results are presented in the form of velocity, microrotation, temperature and concentration profiles within the boundary layer for different parameters entering into the analysis. Also the effects of the pertinent parameters on the local skin friction coefficient and rates of heat and mass transfer in terms of the local Nusselt and Sherwood numbers are also discussed

Similarity Solution for Free Convection Flow of a Micropolar Fluid under Convective Boundary Condition via Lie Scaling Group Transformations

The free convective flow of an incompressible micropolar fluid along permeable vertical plate under the convective boundary condition is investigated. The Lie scaling group of transformations is applied to get the similarity representation for the system of partial differential equations and then the resulting systems of equations are solved using spectral quasi-linearisation method. A quantitative comparison of the numerical results is made with previously published results for special cases and the results are found to be in good agreement. The results of the physical parameters on the developments of flow, temperature, concentration, skinfriction, wall couple stress, heat transfer, and mass transfer characteristics along vertical plate are given and the salient features are discussed

Influence of Non-linear Boussinesq Approximation on Natural Convective Flow of a Power-Law Fluid along an Inclined Plate under Convective Thermal Boundary Condition

In the present investigation, a problem of natural convective flow of a non-Newtonian power-law fluid over an inclined plate saturated in a non-Darcy porous medium is considered. Also, the nonlinear Boussinesq approximation and convective thermal boundary condition are taken into account to address heat and mass transfer phenomena of thermal systems which are operated at moderate and very high temperatures. The steady-state boundary layer equations are non-dimensionalized into non-similar form and then solved numerically by the local non-similarity method with successive linearisation method (SLM). The effects of various physical parameters on the fluid flow, heat and mass transfer characteristics are depicted graphically and analysed in detail

Combined Radiation and Thermo-Diffusion Effects on Natural Convection over a Melting Plate in Porous Medium Saturated with an Electrically Conducting Fluid of Variable Viscosity

AbstractThe combined radiation and thermo-diffusion effects on natural convective transport over a horizontal melting plate embedded in a porous media saturated with an electrically conducting fluid of variable viscosity is investigated in this paper. The Reynolds viscosity model is used to explore the significance of the viscosity of the fluid. Using the numerical method, a solution for the non-dimensional equations is found. The effects of the parameter responsible for the melting surface and other physical parameters on the development of various profiles along horizontal plate are given and the salient features are discussed

A spectral relaxation method for linear and non-linear stratification effects on mixed convection in a porous medium

In this composition, we use a new spectral relaxation method (SRM) to investigate the effects of linear and non-linear stratification on mixed convective transport along a vertical surface embedded in a porous medium and it is viewed for the first time in both aiding and opposing buoyancy cases. The governing partial differential equations are transformed into ordinary differential equations using similarity transformation and then the resulting differential equations are solved numerically using SRM. A comparison is also made about the accuracy of SRM results in relation to the results obtained using the shooting method. We show that the proposed technique is an efficient numerical algorithm with assured convergence that serves as an alternative to common numerical methods for solving nonlinear boundary value problems. A parametric study of the physical parameters involved in the problem is conducted and a representative set of numerical results is illustrated, with accent on the comparison between linear and non-linear stratification. It is significant to notice that the separation of flow is found to be more in the absence of stratification whereas it is less in the presence of stratification. Finally, thermal and solutal stratifications significantly affect the heat and mass transfer rates, besides delay the boundary layer separation

Preoperative assessment of stone free rate following percutaneous nephrolithotomy

Introduction: Renal stones are one of the most common reason for patient’s visit to Urologic outpatient department. PCNL is novel minimally invasive modality for renal stone management and approved by the European Association of Urology (EAU) as 1st line approach. Inspite of high success rates, PCNL can be associated with wide range of complications, ranging from 20-83%.A scoring system which can pre-operatively grade the extent of stone disease, its possible impact on treatment outcomes and occurrence of complications are not only essential but should become an integral part of the care plan.Guy’s score has been externally validated in many studies. In this study we use this Guy’s score in predicting Post op stone free rate following PCNL and also assess the complications of PCNL. Materials and methods: This is retrospective observational Study conducted in Department of urology, Nizam Institute of Medical Sciences, Hyderabad between November 2018 and October2020. Information was obtained from previous records of total 100 patients and analysed retrospectively. All patients with renal calculi > 18 years of age , posted electively for Percutaneous Nephrolithotomy were included in the study. Patients with severe comorbid illness and who underwent Percutaneous Nephrolithotomy in pastwere excluded. Results: Total number of patient included in the study were 100 , (n=100). Majority of the patients were in the 5th decade (27%) Among them males were 64 (64%) and females were 36 (36%). Patient with comorbid conditions were 28 (28%) . Among the comorbidities, Diabetes mellitus was present in 16% of patients.Patients were classified using Guy’s Stone Scoring system to assess the preoperative complexity of the calculus and predict the stone free rate and the complications. Most of the patients were included in the category of Guy’s stone score –1.All patients were evaluated for residual fragments by post PCNL ultrasound on post-operative day 1. Clinically Insignificant Residual Fragments (CIRF)were defined as <4mm, non- obstructive and asymptomatic residual fragments. All perioperative complications were stratified by clavin –Dindo classification system. Peri-operative complications includes intraoperative and post operative complications including CSRF. Total number of patients who had complications include 25 (25%) . Of them 9 patients had grade 1 complication., 6 had grade-2, 7 had grade -3 and 3 had grade -4 complications. Statistical analysis showed significant association between Clinically Significant Residual Fragements, number of punctures required and post operative stay with Guys Stone Score. There is no significant association between Guys stone score and complications graded as per modified ClavienDindoclassification , but there is non significant increased incidence of complication grade with increase in stone score. Conclusion: Guys stone score significantly predict, number of punctures required for PCNL, Stone free rate, Post operative hospital stay

Wegener′s granulomatosis

We report a rare case of Wegener′s granulomatosis involving the prostate gland in a 45-year-old male who presented with acute urinary retention. Treatment was initiated with oral cyclophosphamide and steroids. The prostate size regressed in four weeks and patient voided well after removal of catheter

Entropy Generation Analysis in Nonlinear Convection Flow of Thermally Stratified Fluid in Saturated Porous Medium With Convective Boundary Condition

This article emphasizes the significance of entropy generation analysis and nonlinear temperature density relation on thermally stratified viscous fluid flow over a vertical plate embedded in a porous medium with a thermal dispersion effect. In addition, the convective surface boundary condition is taken into an account. By using the suitable transformations, the governing flow equations in dimensional form are converted into set of nondimensional partial differential equations. Then the local similarity and nonsimilarity procedures are applied to transform the set of nondimensional partial differential equations into set of ordinary differential equations and then the resulting system of equations are solved by Chebyshev spectral collocation method along with the successive linearization. The effect of pertinent parameters, namely, Biot number, mixed convection parameter, and thermal dispersion on velocity, temperature, entropy generation rate, and heat transfer rate are displayed graphically and the salient features are explored in detail