81 research outputs found

    Heat and Mass Transfer by Unsteady Natural Convection over a Moving Vertical Plate Embedded in a Saturated Porous Medium with Chemical Reaction, Soret and Dufour Effects

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    The thermal-diffusion and diffusion-thermo effects on heat and mass transfer by transient free convection flow of over an impulsively started isothermal vertical plate embedded in a saturated porous medium were numerically investigated, considering a homogeneous chemical reaction of first order. The transient, nonlinear and coupled governing equations are solved using an implicit finite-difference scheme. The effects of various parameters on the transient velocity, temperature, and concentration profiles as well as heat and mass transfer rates are analyzed. Numerical results for the unsteady-state velocity, temperature and concentration profiles as well as the axial distributions and the time histories of the skin-friction coefficient, Nusselt number and the Sherwood number are presented graphically and discussed

    Alternative control of early blight of tomato using plant extracts from Acacia nilotica, Achillea fragrantissima and Calotropis procera

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    The in vitro and in vivo antifungal potential of extracts of three wild medicinal plants, (Acacia nilotica (L.) Delile, Achillea fragrantissima (Forssk.) Sch.Bip. and Calotropis procera (Aiton) W. T. Aiton) was examined against Alternaria solani, the causal agent of the early blight of tomato. Aqueous or ethanol extracts of all tested plants reduced the mycelial growth and conidium germination of A. solani in vitro. Ethanol extracts were more effective against the pathogen than the aqueous extracts. Extract of C. procera exhibited more antifungal potential against the pathogen than other plant extracts. Observations by scanning and transmission electron microscopy showed dramatic alterations in the morphology and ultrastructure of A. solani when treated with the ethanol extract of C. procera at a concentration of 20%. Phytochemical screening confirmed the presence of many bioactive constituents in the extracts which were in greater amounts in C. procera than the other two plants. In a plot experiment, both types of extracts from C. procera reduced disease severity. Tomato fruit yield was increased after the treatment with the plant extracts

    Mixed Convection Flow of Non-Newtonian Fluid from Vertical Surface Saturated in a Porous Medium Filled with a Nanofluid

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    The problem of steady, laminar, mixed convection flow of a non-Newtonian fluid past a preamble vertical flat plate embedded in a porous medium saturated with a nanofluid is considered. A mixed convection parameter for the entire range of free-forced-mixed convection is employed and a set of non-similar equations are obtained. These equations are solved numerically by an efficient implicit, iterative, finite-difference method. The obtained results are checked against previously published work for special cases of the problem and are found to be in good agreement. A parametric study illustrating the influence of the various physical parameters on the velocity, temperature and nano-particle volume fraction profiles as well as the local Nusselt and Sherwood numbers is conducted. The obtained results are illustrated graphically and the physical aspects of the problem are discussed

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Impact of anisotropic slip on transient three dimensional MHD flow of ferrofluid over an inclined radiate stretching surface

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    The present study explores the impact of anistropic slip on transient three dimensional MHD flow of Cobalt-kerosene ferrofluid over an inclined radiate stretching surface. The governing partial differential equations for this study are solved by the Thomas algorithm with finite-difference type. The impacts of several significant parameters on flow and heat transfer characteristics are exhibited graphically. The conclusion is revealed that the local Nusselt number is significantly promoted due to influence of thermal radiation whereas diminished with elevating the solid volume fraction, magnet parameter and slip factors. Further, the skin friction coefficients visualizes a considerable enhancement with boosting the magnet and radiation parameters, but a prominent reduction is recorded by elevating the solid volume fraction and slip factors

    Effects of radiation and variable viscosity on unsteady MHD flow of a rotating fluid from stretching surface in porous medium

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    This work is focused on the study of unsteady magnetohydrodynamics boundary-layer flow and heat transfer for a viscous laminar incompressible electrically conducting and rotating fluid due to a stretching surface embedded in a saturated porous medium with a temperature-dependent viscosity in the presence of a magnetic field and thermal radiation effects. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The Rosseland diffusion approximation is used to describe the radiative heat flux in the energy equation. With appropriate transformations, the unsteady MHD boundary layer equations are reduced to local nonsimilarity equations. Numerical solutions of these equations are obtained by using the Runge–Kutta integration scheme as well as the local nonsimilarity method with second order truncation. Comparisons with previously published work have been conducted and the results are found to be in excellent agreement. A parametric study of the physical parameters is conducted and a representative set of numerical results for the velocity in primary and secondary flows as well as the local skin-friction coefficients and the local Nusselt number are illustrated graphically to show interesting features of Darcy number, viscosity-variation, magnetic field, rotation of the fluid, and conduction radiation parameters

    Entropy generation and nanofluid mixed convection in a C-shaped cavity with heat corner and inclined magnetic field

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    A numerical simulation of entropy generation due to MHD mixed convective of water-copper nanofluid in a C-shaped cavity with a heated corner is performed. The cavity is subjected to an inclined uniform magnetic field, and the top wall of the cavity is adiabatic and moves with a constant velocity. The governing equations are formulated by employing the single-phase nanofluid approach and the resulting equations have been solved by the Finite Volume Method (FVM). Impacts of the pertinent parameters on the fluid flow and heat transfer inside the cavity have been presented graphically. The numerical data have been plotted in the portrait of streamlines, isotherms and the average Nusselt numbers. The effects of volume fraction, Hartmann number, and the aspect ratio on the entropy generation and mixed convection of the C-shaped cavity are investigated. It is found that for an aspect ratio = 0.1, increasing the nanofluid volume fraction causes an increment in the heat transfer. At low volume fractions and Hartmann numbers, the outcomes manifest a better thermal performance. Generally, the rate of entropy generation increases by increasing both the Hartmann number and the volume fraction

    On stretched magnetic flow of Carreau nanofluid with slip effects and nonlinear thermal radiation

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    Present article reports the magnetohydrodynamic flow of Carreau nanofluid in the presence of nonlinear thermal radiation. In this model we incorporated slip condition on heat and mass boundary conditions. Similarity transformations are applied to convert the governing dimensional expressions into non-dimensional forms. Runge-Kutta-Fehlberg method of fourth–fifth order using shooting technique utilized to elaborate the numerical solutions of physical phenomenon.A comparative analysis is presented with the previous published data in special case for the justification of present results. The role of physical constraints on liquid velocity, temperature and concentration are discussed through numerical data and plots
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