Hydromagnetic Squeezing Nanofluid Flow between Two Vertical Plates in Presence of a Chemical Reaction

In this study, Hydromagnetic Squeezing Nanofluid flow between two vertical plates in presence of a chemical reaction has been investigated. The governing equations were transformed by similarity transformation and the resulting ordinary differential equations were solved by collocation method. The velocity, temperature, concentration and magnetic induction profiles were determined with help of various flow parameters. The numerical scheme was simulated with aid of MATLAB. The results showed that increasing the squeeze number only boosts velocity and concentration while lowering temperature. Conversely, increasing the Hartmann number, Reynold’s magnetic number, Eckert number and Thermal Grashof number generally increases temperature but decreases both velocity and concentration. Chemical reaction rate and Soret number solely elevate concentration while Schmidt number only reduces it. The results of this study will be useful in the fields of oil and gas industry, plastic processing industries, filtration, food processing, lubrication system in machinery, Microfluidics devices for drug delivery and other related fields of nanotechnology.

Unsteady Hydromagnetic Non-Newtonian Nanofluid Flow Past a Porous Stretching Sheet in the Presence of Variable Magnetic Field and Chemical Reaction

The aim of this study is to examine the unsteady hydromagnetic flow of non-Newtonian nanofluid past a stretching sheet in the presence of variable magnetic field and chemical reaction. The system of non-linear partial differential equations governing the flow was solved using finite difference numerical approximation method. The resulting numerical schemes were simulated in MATLAB software. Furthermore, the skin-friction coefficient, Sherwood number, and Nusselt number have been presented in tabular form and discussed. The findings demonstrated that increasing Reynolds number increases velocity profiles while increasing permeability parameter, suction parameter and angle of inclination for the applied magnetic field reduces the velocity profiles of the fluid flow. Temperature of the fluid increases as the angle of inclination, magnetic number, Reynolds number and Eckert number increase but decreases as Prandtl number increases. Induced magnetic field profiles decrease as magnetic Prandtl number and suction parameter increase. Concentration profiles decrease as the chemical reaction parameter and Schmidt number increase but increase as the Soret number increases. The study is significant because fluid flow and heat transfer mechanisms with the variable magnetic considerations play an important role in magnetohydrodynamic generator or dynamo and magnetohydrodynamic pumps, nuclear reactors, vehicle thermal control, heat exchangers, cancer therapy, wound treatment and hyperthermia.

The application of reed-vibration mechanical spectroscopy for liquids to detect chemical reactions of an acrylic structural adhesive

There remain a number of unsolved problems about chemical reactions, and it is significant to explore new detection methods because they always offer some unique information about reactions from new points of view. For the first time, the solidification course of a modified two-component acrylic structural adhesive is measured by using reed-vibration mechanical spectroscopy for liquids （RMS-L） in this work, and results show that there are four sequential processes of mechanical spectra with time. The in-depth analyses indicate that RMS-L can detect in real-time the generation and disappearance of active free radicals, as well as the chemical cross-link processes in the adhesive. This kind of real-time detection will undoubtedly facilitate the study of the chemical reaction dynamics controlled by free radicals.

Effects of chemical reactions on MHD micropolar fluid flow past a vertical plate in slip-flow regime

Heat and mass transfer effects on the unsteady flow of a micropolar fluid through a porous medium bounded by a semi-infinite vertical plate in a slip-flow regime are studied taking into account a homogeneous chemical reaction of the first order. A uniform magnetic field acts perpendicular to the porous surface absorb micropolar fluid with a suction velocity varying with time. The free stream velocity follows an exponentially increasing or decreasing small perturbation law. Using the approximate method, the expressions for the velocity microrotation, temperature, and concentration are obtained. Futher, the results of the skin friction coefficient, the couple stress coefficient, and the rate of heat and mass transfer at the wall are presented with various values of fluid properties and flow conditions.

High Temperature Chemical Reaction of La_2O_3 in H_3BO_3-C System

The high temperature chemical reaction process of La2O3 in H3BO3-C system was studied by means of XRD and TG-DTA.The results showed that dehydration reaction of H3BO3 occurred in the temperature range of 82～390 ℃;La2O3 and B2O3 reacted to form LaB3O6,LaBO3,and B4C in the temperature range of 836～1400℃;at 1450 ℃,B4C and LaBO3 further reacted to form LaB4,and partial LaB4 and B reacted to form LaB6;at 1500 ℃,LaB4 and B reacting into LaB6 was the main reaction,and the content of LaB6 increased with prolonging time.

Influence of chemical reaction on heat and mass transfer of non-Newtonian fluid with yield stress by free convection from vertical surface in porous medium considering Soret effect

The effect of chemical reaction on free convection heat and mass transfer for a non-Newtonian power law fluid over a vertical flat plate embedded in a fluid-saturated porous medium has been studied in the presence of the yield stress and the Soret effect. The governing boundary layer equations and boundary conditions are cast into a dimen- sionless form by similarity transformations, and the resulting system of equations is solved by a finite difference method. The results are preSented and discussed for concentration profiles, as well as the Nusselt number and the Sherwood number for various values of the parameters, which govern the problem. The results obtained show that the flow field is influenced appreciably by the presence of the chemical reaction parameter γ the order of.the chemical reaction parameter m, the Soret number St, the buoyancy ratio N, the Lewis number Le, and the dimensionless rheological parameter Ω.

Numerical investigation of variable viscosities and thermal stratification effects on MHD mixed convective heat and mass transfer past a porous wedge in the presence of a chemical reaction

An analysis is presented to investigate the effects of variable viscosities and thermal stratification on the MHD mixed convective heat and mass transfer of a viscous, incompressible, and electrically conducting fluid past a porous wedge in the presence of a chemical reaction. The wall of the wedge is embedded in a uniform nonDarcian porous medium in order to allow for possible fluid wall suction or injection. The governing boundary layer equations are written into a dimensionless form by similarity transformations. The transformed coupled nonlinear ordinary differential equations are solved numerically with finite difference methods. Numerical calculations up to the thirdorder level of truncation are carried out for different values of dimensionless parameters. The results are presented graphically, and show that the flow field and other quantities of physical interest are significantly influenced by these parameters. The results are compared with those available in literature, and show excellent agreement.

Simultaneous effects of chemical reaction and Ohmic heating with heat and mass transfer over a stretching surface: A numerical study

In this article, we have considered the simultaneous influence of ohmic heating and chemical reaction on heat and mass transfer over a stretching sheet. The effects of applied magnetic field are also taken into consideration while the induced magnetic field is not considered due to very small magnetics Reynolds number. The governing flow problem comprises of momentum, continuity, thermal energy and concentration equation which are transformed into highly nonlinear coupled ordinary differential equations by means of similarity transforms, which are then, solved numerically with the help of Successive Linearization method(SLM) and Chebyshev Spectral collocation method. Numerical values of skin friction coefficient, local Nusselt number, and Sherwood number are also taken into account with the help of tables. The physical influence of the involved parameters of flow velocity, temperature and concentration distribution is discussed and demonstrated graphically. The numerical comparison is also presented with the existing published results and found that the present results are in excellent agreement which also confirms the validity of the present methodology.

Chemical reaction effects on unsteady MHD flow past semi-infinite vertical porous plate with viscous dissipation

The chemical reaction effect on an unsteady magnetohydrodynamic （MHD） flow past a semi-infinite vertical porous plate with viscous dissipation is analyzed. The governing equations of motion, energy, and species are transformed into ordinary differential equations （ODEs） using the time dependent similarity parameter. The resultant ODEs are then solved numerically by a finite element method. The effects of various parameters on the velocity, temperature, and concentration profiles are presented graphically, and the values of the skin-friction, Nusselt number, and Sherwood number for various values of physical parameters are presented through tables.

Entropy analysis in electrical magnetohydrodynamic(MHD) flow of nanofluid with effects of thermal radiation,viscous dissipation,and chemical reaction

The unsteady mixed convection flow of electrical conducting nanofluid and heat transfer due to a permeable linear stretching sheet with the combined effects of an electric field, magnetic field, thermal radiation, viscous dissipation, and chemical reaction have been investigated. A similarity transformation is used to transform the constitutive equations into a system of nonlinear ordinary differential equations.The resultant system of equations is then solved numerically using implicit finite difference method.The velocity, temperature, concentration, entropy generation, and Bejan number are obtained with the dependence of different emerging parameters examined. It is noticed that the velocity is more sensible with high values of electric field and diminished with a magnetic field. The radiative heat transfer and viscous dissipation enhance the heat conduction in the system. Moreover, the impact of mixed convection parameter and Buoyancy ratio parameter on Bejan number profile has reverse effects. A chemical reaction reduced the nanoparticle concentration for higher values.

Thermal Diffusion Effect on MHD Heat and Mass Transfer Flow past a Semi Infinite Moving Vertical Porous Plate with Heat Generation and Chemical Reaction

The objective of present work is to study the thermo diffusion effect on an unsteady simultaneous convective heat and mass transfer flow of an incompressible, electrically conducting, heat generating/absorbing fluid along a semi-infinite moving porous plate embedded in a porous medium with the presence of pressure gradient, thermal radiation field and chemical reaction. It is assumed that the permeable plate is embedded in a uniform porous medium and moves with a constant velocity in the flow direction in the presence of a transverse magnetic field. It is also assumed that the free stream consists of a mean velocity, temperature and concentration over which are super imposed an exponentially varying with time. The equations of continuity, momentum, energy and diffusion, which govern the flow field, are solved by using a regular perturbation method. The behavior of the velocity, temperature, concentration, Skin-friction, rate of heat transfer and rate of mass transfer has been discussed for variations in the physical parameters. An increase in both Pr and R results a decrease in thermal boundary layer thickness. However, concentration decreases as Kr, Sc increase but it increases with an increase in both So and δ.

Viscous and Ohmic heating effects in doubly stratified free convective flow over vertical plate with radiation and chemical reaction

An analysis is carried out to study the combined effects of viscous and Ohmic heating in the transient, free convective flow of a viscous, incompressible, and doubly stratified fluid past an isothermal vertical plate with radiation and chemical reactions. The governing boundary layer equations are solved numerically by an implicit finite difference scheme of the Crank-Nicolson type. The influence of different parameters on the velocity, the temperature, the concentration, the skin friction, the Nusselt number, and the Sherwood number is discussed with graphical illustrations. It is observed that an increase in either the thermal stratification or the mass stratification parameter decreases the velocity. An increase in the thermal stratification increases the concentration and decreases the temperature while an opposite effect is observed for an increase in the mass stratification. An augmentation in viscous and Ohmic heating increases the velocity and temperature while decreases the concentration. The results are found to be in good agreement with the existing solutions in literature.

Radiation-absorption,chemical reaction,Hall and ion slip impacts on magnetohydrodynamic free convective flow over semi-infinite moving absorbent surface

The investigation of radiation-absorption,chemical reaction,Hall and ion-slip impacts on unsteady MHD free convective laminar flow of an incompressible viscous,electrically conducting and heat generation/absorbing fluid enclosed with a semi-infinite porous plate within a rotating frame has been premeditated.The plate is assumed to be moving with a constant velocity in the direction of fluid movement.A uniform transverse magnetic field is applied at right angles to the porous surface,which is absorbing the fluid with a suction velocity changing with time.The non-dimensional governing equations for present investigation are solved analytically making use of two term harmonic and non-harmonic functions.The graphical results of velocity,temperature and concentration distributions on the analytical solutions are displayed and discussed with reference to pertinent parameters.It is found that the velocity profiles decreased with an increasing in Hartmann number,rotation parameter,the Schmidt number,heat source parameter,while it increased due to an increase in permeability parameter,radiation-absorption parameter,Hall and ion slip parameters.However,the temperature profile is an increasing function of radiation-absorption parameter,whereas an increase in chemical reaction parameter,the Schmidt number Sc or frequency of oscillations decrease the temperature profile on cooling.Also,it is found that the concentration profile is decreased with an escalating in the Schmidt number or the chemical reaction parameter.

EFFECTIVE SOLUTION METHOD OF CHEMICAL REACTION KINETICS WITH DIFFUSE

The time integration method with four-order accuracy, self-starting and implicit for the diffuse chemical reaction kinetics equation or the transient instantaneous temperature filed equation was presented. The examples show that both accuracy and stability are better than Runge-Kutta method with four-order. The coefficients of the equation are stored with sparse matrix pattern, so an algorithm is presented which combines a compact storage scheme with reduced computation cost. The computation of the competitive and consecutive reaction in the rotating packed bed, taken as examples, shows that the method is effective.

Effect of Complexants on Nano-La_2O_3 Prepared by Solid State Chemical Reaction

Precursors were prepared by solid state chemical reaction between LaCl_3 and C_2H_2O_4·2H_2O or NH_4HCO_3 at ambient temperature. Differential temperature analysis (DTA) and thermogravimetric analysis (TGA) were used to determine the decomposing temperature. Oxide (La_2O_3) was obtained by decomposing the precursor for about 2.5 h. X-ray diffraction (XRD), scanning electronic microscope (SEM) and ZETA potentiometer were respectively used to analyze the composition, morphology and size distribution of the products. The results show that La_2O_3 prepared by LaCl_3 and C_2H_2O_4·2H_2O is of ball-like shape and the diameter of particles (95%) is below 50 nm, while La_2O_3 prepared by LaCl_3 and NH_4HCO_3 is net-like.

Calculations of Chemical Reaction Dynamics for D+ H_2(j_i,ν_i=0)→DH(j_f, ν_f=0) + H

The constant Centrifugal potential approximation is Corrected so as to apply to the reactions of rotational excited reactants for D + H2 (j,, νi = 0 ) -DH(jf, νf = 0) + H. Our results show that the contributions from ji≠0 and Ωi terms are not negligible.

Unsteady mixed convection flow over stretching sheet in presence of chemical reaction and heat generation or absorption with non-uniform slot suction or injection

The article examines the unsteady mixed convection flow over a vertical stretching sheet in the presence of chemical reaction and heat generation or absorption with non-uniform mass transfer. The unsteadiness is caused by the time dependent free stream velocity varying arbitrarily with time. Non-similar solutions are obtained nu- merically by solving the coupled nonlinear partial differential equations using the quasi- linearization technique in combination with an implicit finite difference scheme. To reveal the tendency of the solutions, typical results for the local skin friction coefficient and the local Nusselt and Sherwood numbers are presented for different values of parameters. The effects of various parameters on the velocity, temperature, and concentration distributions are discussed here. The present numerical results are compared with the previously published work, and the results are found to be in excellent agreement.

An efficient light-to-heat conversion coupling photothermal effect and exothermic chemical reaction in Au NRs/V_(2)C MXene membranes for high-performance laser ignition

MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years.Herein,we report the intriguing light-to-heat conversion property of vanadium carbide(V_(2)C)MXene under irradiation of millisecond laser pulse.Unlike the typical photothermal materials,the V_(2)C MXene not only converts the incident laser energy to heat by the physical photothermal effect,but also triggers the exothermic oxidation of the V_(2)C MXene.The oxidation could be greatly promoted with addition of plasmonic Au nanorods(Au NRs)for light absorption enhancement.Owing to the unique light-to-heat conversion property,the Au NRs/V_(2)C MXene membrane could serve as high temperature pulse(HTP)generators that is proposed for numerous applications with high demand for immediacy.As a proof-of concept application,Au NRs/V_(2)C MXene membrane was applied for laser ignition of the high energy density materials,such as 2,4,6,8,10,12-(hexanitrohexaaza)cyclododecane(HNIW or CL-20).An improved ignition performance,in terms of lowered laser threshold,is achieved as compared to the state-of-the-art light-to-heat conversion materials.

A statistical model for predicting thermal chemical reaction rate

A simple model based on the statistics of individual atoms [Europhys. Lett. 94 40002 （2011）] or molecules [Chin. Phys. Lett. 29 080504 （2012）] was used to predict chemical reaction rates without empirical parameters, and its physical basis was further investigated both theoretically and via MD simulations. The model was successfully applied to some reactions of extensive experimental data, showing that the model is significantly better than the conventional transition state theory. It is worth noting that the prediction of the model on ab initio level is much easier than the transition state theory or unimolecular RRKM theory.

A Novel Oscillating Chemical Reaction Using Ninhydrin as Single Organic Substrate

A novel oscillating chemical reaction using ninhydrin as a single organic substrate was represented in this paper. It distinguished from the classically catalyzed BZ oscillating chemical reaction due to there was no active methene （CH2=） and/or enol structure in the ninhydrin molecule, which served as single organic substrate. This suggested that the substrates used in catalyzed BZ reaction were not always the organic compounds containing active methene （CH2=） and/or enol structure and bromination process in this kind of catalyzed chemical oscillating reaction was not also necessary.