Soil with heavy metals contamination, mainly lead (Pb), cadmium (Cd), and chromium (Cr) is a progressively worldwide alarming environmental problem. Recently, biochar has been used as a soil ...amendment to remediate contaminated soils, but little work has been done to compare with other organic amendments like compost. We investigated biochar and compost's comparative effect on Pb, Cd, and Cr immobilization in soil, photosynthesis, and growth of maize plants. Ten kg soil was placed in pots and were spiked with Pb, Cd, and Cr at concentrations 20, 10, 20 mg kg
. The biochar and compost treatments included 0, 0.5, 1, 2, and 4% were separately applied to the soil. The crop from pots was harvested after 60 days. The results show that the highest reduction of AB-DTPA extractable Pb, Cd, and Cr in soil was 79%, 61% and 78% with 4% biochar, followed by 61%, 43% and 60% with 4% compost compared to the control, respectively. Similarly, the highest reduction in shoot Pb, Cd, and Cr concentration was 71%, 63% and 78%with 4% biochar, followed by 50%, 50% and 71% with 4% compost than the control, respectively. The maximum increase in shoot and dry root weight, total chlorophyll contents, and gas exchange characteristics were recorded with 4% biochar, followed by 4% compost than the control. The maximum increase in soil organic matter and total nitrogen (N) was recorded at 4% biochar application while available phosphorus and potassium in the soil at 4% compost application. It is concluded that both biochar and compost decreased heavy metals availability in the soil, reducing toxicity in the plant. However, biochar was most effective in reducing heavy metals content in soil and plant compared to compost. In the future, more low-cost, eco-friendly soil remediation methods should be developed for better soil health and plant productivity.
The combine effects of magnetic field bioconvection, Brownian motion and thermophoresis on a free convection nanofluid flow over a stretching sheet containing gyrotactic microorganisms are ...investigated. The self-similar Buongiorno model is analyzed first time for stretching sheet numerically. The present results are compared with available data and are found in an excellent agreement. Pertinent results are presented graphically and discussed quantitatively with respect to variation in bioconvection parameters.
•Two dimensional MHD flow in a suspension of gyrotactic microorganisms and nanoparticles over a stretching surface is discussed first paper in literature.•Governed problem for proposed model solved numerically using fourth-order Runge–Kutta–Fehlberg method.•Good agreement in comparison with previous studies.•Tabulated physical quantities and graphics of all flow profiles.•Graphics of reduced skin friction coefficient, when the different flow parameters vary.
This article is intended for investigating the effects of magnetohydrodynamics (MHD) and volume fraction of carbon nanotubes (CNTs) on the flow and heat transfer in two lateral directions over a ...stretching sheet. For this purpose, three types of base fluids specifically water, ethylene glycol and engine oil with single and multi-walled carbon nanotubes are used in the analysis. The convective boundary condition in the presence of CNTs is presented first time and not been explored so far. The transformed nonlinear differential equations are solved by the Runge–Kutta–Fehlberg method with a shooting technique. The dimensionless velocity and shear stress are obtained in both directions. The dimensionless heat transfer is determined on the surface. Three different models of thermal conductivity are comparable for both CNTs and it is found that the Xue 1 model gives the best approach to guess the superb thermal conductivity in comparison with the Maxwell 2 and Hamilton and Crosser 3 models. And finally, another finding suggests the engine oil provides the highest skin friction and heat transfer rates.
Heat transfer difference for different base fluids in the presence of SWCNTs and MWCNTs. Xue model has the best approach to guess the superb thermal conductivity as compare to rest of models. Display omitted
•MHD and CNTs effects are incorporated within the base fluids.•Three different types of base fluids have been considered.•Hot fluid along the wall is also considered.•Obtained coupled ordinary differential equations are investigated numerically.•Xue model has the best approach to guess the superb thermal conductivity as compare to rest of models.
This study investigates the magnetohydrodynamic (MHD) flow of ferrofluid along a stretching cylinder. The velocity slip and prescribed surface heat flux boundary conditions are employed on the ...cylinder surface. Water as conventional base fluid containing nanoparticles of magnetite (Fe3O4) is used. Comparison between magnetic (Fe3O4) and non-magnetic (Al2O3) nanoparticles is also made. The governing non-linear partial differential equations are reduced to non-linear ordinary differential equations and then solved numerically using shooting method. Present results are compared with the available data in the limiting cases. The present results are found to be in an excellent agreement. It is observed that with an increase in the magnetic field strength, the percent difference in the heat transfer rate of magnetic nanoparticles with Al2O3 decreases. Surface shear stress and the heat transfer rate at the surface increase as the curvature parameter increases, i.e curvature helps to enhance the heat transfer.
The aim of the present study is to analyze the flow of three-dimensional water-based nanofluid over an exponentially stretching sheet. The transport equations are transformed into nonlinear, coupled ...similarity equations using three-dimensional exponential type similarity transformations. These equations are solved numerically to obtain the velocities and temperature in the respective boundary layers. Results are presented to illustrate the effects of various parameters including the temperature exponent, stretching parameter and volume fraction of three different types of nanoparticles, such as copper (Cu), alumina (Al2O3) and titanium dioxide (TiO2) with water as a base fluid.
Present model is devoted for the stagnation point flow of nanofluid with magneto-hydrodynamics (MHD) and thermal radiation effects passed over a stretching sheet. Moreover, we have considered the ...combined effects of velocity and thermal slip. Condition of zero normal flux of nanoparticles at the wall for the stretched flow phenomena is yet to be explored in the literature. Convinced partial differential equations of the model are transformed into the system of coupled nonlinear differential equations and then solved numerically. Graphical results are plotted for velocity, temperature and nanoparticle concentration for various values of emerging parameters. Variation of stream lines, skin friction coefficient, local Nusselt and Sherwood number are displayed along with the effective parameters. Final conclusion has been drawn on the basis of both numerical and graphs results.
Geometry of the problem and flow behavior of the nanofluid. Display omitted
•Stagnation, thermal radiation and MHD effects.•Combine effects of thermal and velocity slip.•Effects of Brownian motion and thermophoresis.•Compatible Buongiorno׳s model considered for effective thermal conductivity•Obtained coupled ordinary differential equations are investigated numerically.
In this article, we studied MHD peristaltic flow of a Carreau nanofluid in an asymmetric channel. The flow development is carried out in a wave frame of reference moving with velocity of the wave c1. ...The governing nonlinear partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations using similarity transformations and then tackled numerically using the fourth and fifth order Runge–Kutta–Fehlberg. Numerical results are obtained for dimensionless velocity, stream function, pressure rise, temperature and nanoparticle volume fraction. It is found that the pressure rise increases with increase in Hartmann Number and thermophoresis parameter.
In the present article, we considered two-dimensional steady incompressible Oldroyd-B nanofluid flow past a stretching sheet. Using appropriate similarity variables, the partial differential ...equations are transformed to ordinary (similarity) equations, which are then solved numerically. The effects of various parameters, namely, Deborah numbers Formula: see text and Formula: see text, Prandtl parameter Formula: see text, Brownian motion Formula: see text, thermophoresis parameter Formula: see text and Lewis number Formula: see text, on flow and heat transfer are investigated. To see the validity of the present results, we have made the comparison of present results with the existing literature.
The peristaltic flow of nanofluids is an emerging area of scientific research due to its vital industrial and medical applications. Herein, a model study is conducted to numerically investigate, the ...electroosmotically augmented peristaltic pumping of electrically conducting aqueous ionic nanofluid through an inclined asymmetric channel. The behavior of the model for various involved parameters is expressed through a set of graphs. The velocity profile gained a significant increment for Joule heating and electroosmotic velocity parameters. The velocity dropped for the Hartmann number, while a dual behavior is noted for the thermal Grashof number. However, the magnetic number enhances the temperature, while a lower temperature is perceived for the electroosmotic velocity and Debye length parameters. The streamline pattern for the fluid flow subject to multiple values of the electroosmotic velocity parameter can be seen to indicate that for negative values of the parameter, a larger number of streamlines are circulated compared to the case when the electric field is absent, that is, UHS=0${U_{HS}} = \;0$. However, in the case of an opposing electric field, that is, for the positive values of the parameter, the streamline bolus occurs across the centerline of the channel.
The peristaltic flow of nanofluids is an emerging area of scientific research due to its vital industrial and medical applications. Herein, a model study is conducted to numerically investigate, the electroosmotically augmented peristaltic pumping of electrically conducting aqueous ionic nanofluid through an inclined asymmetric channel. The behavior of the model for various involved parameters is expressed through a set of graphs. The velocity profile gained a significant increment for Joule heating and electroosmotic velocity parameters.…
The entropy generation due to heat transfer and fluid friction in mixed convective peristaltic flow of methanol-Al2O3 nano fluid is examined. Maxwell’s thermal conductivity model is used in analysis. ...Velocity and temperature profiles are utilized in the computation of the entropy generation number. The effects of involved physical parameters on velocity, temperature, entropy generation number, and Bejan number are discussed and explained graphically.
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