A Levenberg-Marquardt backpropagation method for unsteady squeezing flow of heat and mass transfer behaviour between parallel plates

In this study, a new computing model by developing the strength of feed-forward neural networks with Levenberg-Marquardt Method (NN-BLMM) based backpropagation is used to find the solution of nonlinear system obtained from the governing equations of unsteady squeezing flow of Heat and Mass transfer behaviour between parallel plates. The governing partial differential equations (PDEs) for unsteady squeezing flow of Heat and Mass transfer of viscous fluid are converting into ordinary differential equations (ODEs) with the help of a similarity transformation. A dataset for the proposed NN-BLMM is generated for different scenarios of the proposed model by variation of various embedding parameters squeeze Sq, Prandtl number Pr, Eckert number Ec, Schmidt number Sc and chemical-reaction-parameter [Formula: see text]. Physical interpretation to various embedding parameters is assigned through graphs for squeeze Sq, Prandtl Pr, Eckert Ec, Schmidt Sc and chemical-reaction-parameter [Formula: see text]. The processing of NN-BLMM training (T.R), Testing (T.S) and validation (V.L) is employed for various scenarios to compare the solutions with the reference results. For the fluidic system convergence analysis based on mean square error (MSE), error histogram (E.H) and regression (R.G) plots is considered for the proposed computing infrastructures performance in term of NN-BLMM. The results based on proposed and reference results match in term of convergence up to 10-02 to 10-08 proves the validity of NN-BLMS. The Optimal Homotopy Asymptotic Method (OHAM) is also used for comparison and to validate the results of NN-BLMM.

Chemical reaction and thermal radiation effects on magnetohydrodynamics flow of Casson–Williamson nanofluid over a porous stretching surface

The flow of Casson–Williamson fluid on a stretching surface is considered for the study. The movement of fluid is examined under the effect of external magnetic field, thermal radiation and chemical consequences. The model is formed by considering all the physical aspects responsible for the physical mechanism. The formed mathematical model (partial differential equation) is numerically solved after transforming it into an ordinary one (ordinary differential equation) via similarity invariants. The physical mechanism for velocity, temperature, and concentration is examined through the associated parameters like radiation index, Williamson and Casson parameter, suction/injection parameter, porosity index, and chemical reaction parameter.

Origin of Enantioselectivity Reversal in Lewis Acid-Catalysed Michael Additions Relying on the Same Chiral Source

Enantiodivergence is an important concept in asymmetric catalysis that enables access to both enantiomers of a product relying on the same chiral source as reagent. This strategy is particularly appealing as an alternate approach when only one enantiomer of the required chiral ligand is readily accessible but both enantiomers of the product are desired. Despite the potential significance, general catalytic methods to effectively reverse enantioselectivity by changing an achiral reaction parameter remain underdeveloped. Herein we report our studies focused on elucidating the origin of metal-controlled enantioselectivity reversal in Lewis acid-catalysed Michael additions. Rigorous experimental and computational investigations reveal that specific interactions between the substrate and ligand depending on the choice of metal catalyst are a key factor responsible for the observed enantiodivergence. This holds potential to further our understanding of and facilitate the design of future enantiodivergent transformations.

Bioconvection of a Radiating Hybrid Nanofluid Past a Thin Needle in the Presence of Heterogeneous-Homogeneous Chemical Reaction

: The photo catalytic nature of TiO_2 finds applications in medicinal field to kill cancer cells, bacteria and viruses under mild ultraviolet illumination and the antibacterial characteristic of Ag makes the composition Ag-TiO_2 applicable for various purposes. It can also be used in other engineering appliances and industries such as humidity sensor, coolants and in footwear industry. Hence, this study deals with the analysis of the effects of Magnetic field, thermal radiation and quartic autocatalysis of heterogeneous-homogeneous reaction in an electrically conducting Ag-TiO_2-H_2 O hybrid nanofluid. Furthermore, the gyrotactic microorganisms are used as active mixers to prevent agglomeration and sedimentation of TiO_2 that occurs due to its hydrophobic nature. The Mathematical model takes the form of partial differential equations with viscosity and thermal conductivity being the functions of volume fraction. These equations are converted to ordinary differential equations by using similarity transformation and are solved by RKF-45 method with the aid of shooting method. It is observed that the increase in the size of the needle enhances the overall performance of the hybrid nanofluid. Furthermore, the temperature of the hybrid nanofluid increases with the increase in volume fraction. It is observed that the friction produced by the Lorentz force increases the temperature of the nanofluid. It is further observed that the heterogeneous reaction parameter has more significant effect on the concentration of bulk fluid than the homogeneous reaction parameter.

Selective catalytic synthesis of short chain oxymethylene ethers by a heteropoly acid – a reaction parameter and kinetic study

Oxymethylene ethers (OME) are considered as low-emission additive or replacement to diesel fuel. They can be synthesized by different routes based on C1 platform chemicals in different oxidation states. The...

Effect of Thermal Radiation and Chemical Reaction on MHD Flow of Blood in Stretching Permeable Vessel

This paper focuses on the theoretical analysis of blood flow in the presence of thermal radiation and chemical reaction under the influence of time dependent magnetic field intensity. Unsteady non linear partial differential equations of blood flow consider time dependent stretching velocity, the energy equation also accounts time dependent temperature of vessel wall and the concentration equation includes the time dependent blood concentration. The governing non linear partial differential equations of motion, energy and concentration are converted into ordinary differential equations using similarity transformations solved numerically by applying ode45. The effect of physical parameters, viz., the permeability parameter, unsteadiness parameter, Prandtl number, Hartmann number, thermal radiation parameter, chemical reaction parameter and Schmidt number on flow variables, viz., velocity of blood flow in vessel, temperature and concentration of blood, has been analyzed and discussed graphically. From the simulation study the following important results are obtained: velocity of blood flow increases with the increment of both permeability and unsteadiness parameter. The temperature of blood increases at the vessel wall as the Prandtl number and Hartmann number increase. Concentration of blood decreases as time dependent chemical reaction parameter and Schmidt number increases.