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Devices of solar water desalination confront many problems including the low thermal properties of phase change materials (PCMs) such as heat transfer, storage of heat capacity, charging and discharging capability. Thus, these properties need to be improved by using a simple and novel procedure. So, incorporation and dispersion of hybrid nano-powders inside PCMs is considered a simple and novel procedure to improve the thermal properties of solar water desalination devices. The present article is focused on incorporating different nano-powders of MWCNTs and Al2O3 inside PCMs to improve the thermal characteristics of solar water desalination applications. Different nano-powders of MWCNTs and Al2O3 have been incorporated as: (i) 1.0 mass% Al2O3, (ii) 1.0 mass% MWCNTs, and (iii) hybrid 1.0 mass% of Al2O3 + 1.0 mass% MWCNTs, inside a constant amount of 250 gm RT-65HC paraffin wax. An innovative prototype was designed and produced to measure the thermal characteristics of solar water desalination devices. Various analyses have been carried out to study the influence of nano-powders scattering on the morphological, microstructural observations, chemical and thermal characteristics, including SEM, XRD, FT-IR, TGA, DSC, thermal conductivity, and infrared thermography. Microstructural observations showed that the excellent dispersion of nano-powders was at hybrid nano-additives of 1.0 mass% MWCNTs + 1.0 mass% Al2O3 inside PCMs. The uniform scattering of hybrid 1.0 mass% MWCNTs + 1.0 mass% Al2O3 inside PCMs assists to eliminate any defects. Finally, thermal characteristics of hybrid nano-additives phase change materials (NAPCMs) were improved specially in thermal stability, latent heat temperature, and thermal conductivity at 89%, 80%, and 32.8%, respectively. [ABSTRACT FROM AUTHOR]

The bioconvective flow of non-Newtonian fluid induced by a stretched surface under the aspects of combined magnetic and porous medium effects is the main focus of the current investigation. Unlike traditional aspects, here the viscoelastic behavior has been examined by a combination of both micropolar and second grade fluid. Further thermophoresis, Brownian motion and thermodiffusion aspects, along with variable thermal conductivity, have also been utilized for the boundary process. The solution of the nonlinear fundamental flow problem is figured out via convergent approach via Mathematica software. It is noted that this flow model is based on theoretical flow assumptions instead of any experimental data. The efficiency of the simulated solution has been determined by comparing with previously reported results. The engineering parameters' effects are computationally evaluated for some definite range. [ABSTRACT FROM AUTHOR]

Chirps are familiar in nature, have a built-in resistance to noise and interference, and are connected to a wide range of highly oscillatory processes. Detecting chirp oscillating patterns by traditional Fourier series is challenging because the chirp frequencies constantly change over time. Estimating such types of functions considering the partial sums of a Fourier series in Fourier analysis does not permit an approximate solution, which entails more Fourier coefficients required for signal reconstruction. The standard Fourier series, therefore, has a poor convergence rate and is an inadequate approximation. In this study, we use a parameterized orthonormal basis with an adjustable parameter to match the oscillating behavior of the chirp to approximate linear chirps using the partial sums of a generalized Fourier series known as fractional Fourier series, which gives the best approximation with only a small number of fractional Fourier coefficients. We used the fractional Fourier transform to compute the fractional Fourier coefficients at sample points. Additionally, we discover that the fractional parameter has the best value at which fractional Fourier coefficients of zero degrees have the most considerable magnitude, leading to the rapid decline of fractional Fourier coefficients of high degrees. Furthermore, fractional Fourier series approximation with optimal fractional parameters provides the minimum mean square error over the fractional Fourier parameter domain. [ABSTRACT FROM AUTHOR]

The unsteady MHD free convection heat and mass transfer flow of a viscous, incompressible, and electrically conducting fluid passing through a vertical plate embedded in a porous medium in the presence of chemical reactions and thermal radiation is investigated. The effects of the Hall current, rotation and Soret are studied. Using the perturbation approach, one can obtain an accurate analytical solution to the governing equations for the fluid velocity, fluid temperature, and species concentration, provided that the initial and boundary conditions are acceptable. It is possible to obtain expressions for the shear stress, rate of heat transfer, and rate of mass transfer for both plates with the ramping temperature and isothermal conditions. On the one hand, the numerical values of the primary and secondary fluid velocities, fluid temperature, and species concentration are presented graphically. On the other hand, the numerical values of the shear stress and rate of mass transfer for the plate are presented in tabular form for various values of the relevant flow parameters. These values are given for a range of pertinent flow parameters. It was determined that an increase in the Hall and Soret parameters over the whole fluid area leads to a corresponding increase in the resulting velocity. The resultant velocity continually climbs to a high level due to the contributions of the thermal and solute buoyancy forces. Lowering the heat source parameter reduces the temperature distribution, resulting in a lower overall temperature. When there is a rise in the chemical reaction parameter over the whole fluid area, there is a corresponding decrease in the concentration. The concentration buoyancy force, Hall current, and Prandtl number reduce the skin friction. On the other hand, the permeability of the porous medium, rotation, chemical reaction, the Soret number, thermal buoyancy force, and mass diffusion all have the opposite effects on the skin friction. [ABSTRACT FROM AUTHOR]

Due to the higher coefficients of heat and mass transfer, the jet flow has become an effective source for the transfer of heat and mass in various industries. Due to these high coefficients, the heat and mass transfer rates will be high in the appliances equipped with the jet flow. Further, the existence of the magnetic field helps in controlling the velocity and the presence of the gyrotactic microorganisms ensure proper mixing of nanoparticles. A dilute nanoparticle suspension is assumed so that it will not affect the movement of motile cells that leads to bioconvection. Hence, this paper aims to analyze the characteristics of heat transfer as well as mass transfer of the jet flow of Williamson nanofluid past a porous stretching sheet in the existence of microorganisms. The mathematical model obtained as a result of these assumptions is transformed into nonlinear ordinary differential equations for which acceptable solutions are obtained using the numerical method. The results thus obtained are presented graphically and based on the outcomes, it is perceived that the magnetic field has control over the velocity profile thus influencing the thermal profile. The increase in the Williamson parameter also reduces the velocity of the fluid flow. Further, an increase was noticed in the thermal and concentration profiles of the nanofluid for higher values of thermophoresis parameter and the increase in the porosity reduced the speed of the flow of nanofluid. The article deals with the analysis of the flow of Williamson nanofluid in the presence of Arrhenius activation energy. Further, the gyrotactic microorganisms are suspended in the base fluid to ensure stable distribution of nanoparticles and meanwhile, the impact of thermophoresis and Brownian motion are also analyzed. As a result of the increase in the activation energy parameter, the nanoparticles concentration found to decrease. [ABSTRACT FROM AUTHOR]

This paper investigates modeling and analysis of entropy generation in bioconvective non-radiative Sisko nanofluid flow by stretchable cylinder. Momentum relation is modeled in view of Darcy Forchheimer and porosity effects. Dissipation, Joule heating and heat generation impacts are accounted in energy relation. Mass concertation communication is constructed in manifestation of Arrhenius energy and chemical reaction. Brownian dispersion and thermophoretic effects of solid nanoparticles in Sisko liquid are stabilized by self-propelled gyrotactic microorganisms. The flow governing model is obtained utilizing boundary layer concepts. Fluid transport equations are made dimensionless via transformations and then tackled by NDSolve code in Mathematica package. Variation in transport properties versus effective parameters is examined via graphs and tables. It is perceived from obtained results that Sisko nanofluid velocity decays versus higher curvature parameter, Hartman number, porosity and Forchheimer variable. Further, it is observed that temperature distribution enhances for heat generation variable, Eckert number, Brownian movement variable, thermophoresis motion parameter and Prandtl number. Main observations are listed in the end. Entropy generation in bioconvective Sisko nanofluid flow by stretchable cylinder is investigated. Fluid transportation model is obtained in manifestation of Arrhenius energy, chemical reaction, Joule heating and heat generation. It is perceived from obtained results that Sisko nanofluid velocity decays versus higher Hartman number and porosity variable. [ABSTRACT FROM AUTHOR]

The motivation of current contribution is to signify the assessment of entropy generation in the flow of generalized Newtonian fluid generated under the influence of electro‐osmosis and peristalsis. The flow has been confined by a tapered channel with certain flow assumptions. The fundamental conservations laws of mass, momentum, energy and concentration along with the Poisson and Nernst‐Planck equations are used to identify the problem in given domain. The Poisson equation is solved analytically for potential function under the Debye‐Huckel linearization approximation while the expressions are attained with association of conservation concept under widely used assumptions of minor Reynolds number and long wavelength. The velocity in axial direction, temperature and nanoparticles profiles are numerically approximated using shooting method. The electric force parameter and radiative constant are being expressed against different flow, temperature and concentration features via various sketches. The results for Newtonian and Carreau fluid as particular case are also presented via numerous plots and tables. It is expected that the obtained theoretical results are very useful for the resilience of medical instatements. [ABSTRACT FROM AUTHOR]

We obtain the clean semi-analytical solutions with method of directly defining inverse mapping (MDDiM) to the system of nonlinear equations arising in the magnetohydrodynamic (MHD) convection motion of Molybdenum disulfide (MoS2) engine-oil intrinsic nanofluid in a circumnavigatethe structure is considered for analysis. Finding the solutions by using MDDiM is a novel idea and first time solving for the system of nonlinear partial differential equations. We have chosen inverse linear mapping for the five-term solution and it emphasizes by residual error and this gives the low error (10−2 to 10−17) and can easily derive deformation terms by spending very low CPU time. Based on the proposed method, the convergence rate, accuracy, and efficiency of the governing equations are demonstrated, and result outputs shown in tabular and graphically, which exhibit meaningful structures and advantages in science and engineering. [ABSTRACT FROM AUTHOR]

Nanoparticles typically have dimensions of less than 100 nm. Scientists around the world have recently become interested in nanotechnology because of its potential applications in a wide range of fields, including catalysis, gas sensing, renewable energy, electronics, medicine, diagnostics, medication delivery, cosmetics, the construction industry, and the food industry. The sizes and forms of nanoparticles (NPs) are the primary determinants of their properties. Nanoparticles' unique characteristics may be explored for use in electronics (transistors, LEDs, reusable catalysts), energy (oil recovery), medicine (imaging, tumor detection, drug administration), and more. For the aforementioned applications, the synthesis of nanoparticles with an appropriate size, structure, monodispersity, and morphology is essential. New procedures have been developed in nanotechnology that are safe for the environment and can be used to reliably create nanoparticles and nanomaterials. This research aims to illustrate top-down and bottom-up strategies for nanomaterial production, and numerous characterization methodologies, nanoparticle features, and sector-specific applications of nanotechnology. [ABSTRACT FROM AUTHOR]

Following to improved thermal impact of hybrid nanomaterials, wide range applications of such materials is observed in the thermal engineering, extrusion systems, solar energy, power generation, heat transfer devices etc. The hybrid nanofluid is a modified form of nanofluid which is beneficial for improving energy transfer efficiency. In current analysis, the solid nanoparticles aluminium ( ϕ Al 2 O 3 ) and copper ( ϕ Cu ) have been mixed with water to produce a new hybrid nanofluid. The investigation of a steady two-dimensional mixed convection boundary layer flow of the resultant hybrid nanofluid on a vertical exponential shrunk surface in the existence of porous, magnetic, thermal radiation, velocity, and thermal slip conditions is carried out. Exponential similarity variables are adopted to transform the nonlinear partial differential equation into a system of ordinary differential equations which has been then solved by employing the shooting method in Maple software. The obtained numerical results such as coefficient of skin friction f ″ 0 , heat transfer rate - θ ′ 0 , velocity f ′ η and temperature θ η distributions are presented in the form of different graphs. The results revealed that duality exists in solution when the suction parameter S ≥ S ci in assisting flow case. Due to non-uniqueness of solutions, a temporal stability analysis needs to be performed and the result indicates that the upper branch is stable and realizable compared to the lower branch. [ABSTRACT FROM AUTHOR]

Electrolytic in-process dressing (ELID) is a grinding technique used to generate high-quality surfaces on hard and brittle material. Oxide layer formed on grinding wheel during ELID grinding heavily influences the surface roughness of the workpiece. To study the microscopic structure of the oxide layer and model the thickness of it, we conducted a previously reported study on metallic-bonded prism samples with major adjustments and implementations. The parameter studied are voltage, electrode-grinding wheel gap, and coolant flow rate. Scanning electron microscopy (SEM) images of cross-section of the oxidation sites were captured and compared and oxide layer thickness was accurately measured. All three parameters are found to significantly affect the formation of the oxide layer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Concepts and definitions. • Fluid dynamics. • Non-viscous flow. • Conservation of mass and energy. • Darcy-Forchheimer Flow. • Entropy generation. • Artificial neural networks with Levenberg-Marquardt backpropagation • Molybdenum disulfide and silicon dioxide nanoparticles • Thermal radiation • Heat generation • Numerical solutions The work in hand examines the entropy generation of magnetohydrodynamic Darcy-Forchheimer nanofluid flow model (MHD-DFNM) over a stretched surface via Artificial back propagated neural networks with Levenberg Marquardt Algorithm (ABNN-LMA). Two types of nanoparticles i.e Silicon dioxide (SiO 2) and Molybdenum disulfide (MoS 2) and continuous phase liquid i.e propylene glycol is considered. The PDEs of MHD-DFNM are transformed into coupled ODEs via appropriate (similarity) transformations. The reference dataset is obtained by the variation of 1st and 2nd order slip parameters (γ 1 and γ 2), porosity parameter (β), viscosity parameter (λ), radiation parameter(R), volume friction coefficient(ϕ), heat generation/absorption parameter(Q), Biot number (B 1) and Eckert number (Ec) from Homotopy Analysis Method (HAM). The reference data is executed in training/testing/validation sets to find and analyze the approximated solution of designed ABNN-LMA as well as it's comparison with reference data solution. The better performance is consistently certified with Mean Squared Error (MSE) curves, regression index and error histogram study. Results reveal that, increase in values of porosity parameter declines the velocity profile for both SiO 2 and MoS 2 nanoparticles suspended in propylene glycol nanofluids. The thermal profile improves for both SiO 2 − propylene glycol and MoS 2 − propylene glycol nanofluids when heat generation parameter increases. [ABSTRACT FROM AUTHOR]