Zero Mass Research Articles

Bioconvective Homann flow of tangent hyperbolic nanofluid due to spiraling disk with convective and zero mas flux constraints

The phenomenon of bioconvection in nanomaterials presents novel applications in the biotechnology, biofuels, enzymes, biomedical engineering and energy systems. Current exploration explores the applications of bioconvection in Homann flow of nanofluid due to spiraling of disk theoretically. The generalized model namely tangent hyperbolic fluid is used to predicts the rheological and thermal impact. The stability of nanofluid is ensured with interaction of motile microorganisms. The Boungrino nanofluid model with thermophoresis and Brownian motion features is used to perform the analysis The thermal distribution of nanofluids is proceeded by utilizing the zero mass thermal constraints. The similarity variables are introduced in order to estimating the dimensionless formulation. The Keller Box method with higher efficiency is imposed with implicit finite difference numerical algorithm. The main observations reveal that with enhancing the radial velocity and azimuthal velocity decreases with increasing sparling angle. For highly viscous case, a decrement in the azimuthal velocity has been observed.

Interaction of Variable Fluid Properties with Electrokinetically Modulated Peristaltic Flow of Reactive Nanofluid: A Thermodynamical Analysis

In the present study, the interaction of variable fluid properties with electrokinetically regulated peristaltic transportation of a reactive nanofluid embedded in a porous space is studied. The nanofluid saturates the porous space/medium with inhomogeneous porosity, which changes with distance from the channel boundary. It is assumed that nanofluids are accompanied by variable thermal conductivity and viscosity. The impacts of magnetic field, Brownian motion, electric field, viscous dissipation, chemical reaction, mixed convection, and thermophoresis are incorporated. Moreover, the contribution of zero mass flux boundary condition is executed. The complexity of the equations describing the flow of a nanofluid is reduced by applying the lubrication theory. The fully non-linear equations are solved by utilizing a numerical technique. Particular attention is paid to the analysis of entropy optimization, since its minimization is the best measure to enhance the efficiency of thermal systems. These results demonstrate that a positively oriented external electric field contributes to an increase in nanofluid velocity. Temperature of nanofluid increases more rapidly due to an augmentation in Joule heating parameter. It is noticed that the temperature of water is comparatively lower than that of kerosene. The system’s energy loss can be reduced when the thermal conductivity parameter enhance. The magnitude of Bejan number is enhanced by increasing electroosmotic parameter. Further, a substantial decrement in concentration profile is perceived when the Schmidt number is augmented.

Design and Evaluation of a Zero Mass Flow Liner

In this study, the concept of a zero mass flow liner is evaluated. The concept enables impedance control by the induction of, acoustically actuated, periodic bias flow through the facing sheet of the liner. By means of the periodic bias flow, the impedance of the liner is adapted to different grazing flow conditions. The equivalent fluid impedance model for perforated plates is modified to account for the effects of periodic bias and grazing flow. A generally applicable optimization routine, using the impedance of the lined surface as a boundary condition in a numeric calculation, is implemented. Based on the results of the optimization, a zero mass flow liner is manufactured and evaluated experimentally. The damping characteristics are assessed in the form of dissipated energy along the lined surface. Prediction and measurements show reasonable agreement. The zero mass flow liner delivers broadband dissipation of high peak value over a range of grazing flow Mach numbers. Under grazing flow, the effect of periodic bias flow is reduced. For a ratio of grazing to bias flow velocities larger than five, no appreciable effect is found. This poses considerable energy requirements on the actuation source for the application in high-Mach-number flow regimes.

Ground state solutions for the Chern-Simons-Schrödinger equation with zero mass potential

In this paper, we consider the nonlinear Chern-Simons-Schrödinger equation \begin{equation*} -\Delta u+ \Big ( \frac{h_u^2(|x|)}{|x|^2} +\int^{\infty}_{|x|}\frac{h_u(s)}{s}u^2(s)ds \Big ) u =-a|u|^{p-2}u+f(u),\,\, x\in\mathbb R^2, \end{equation*} where $a > 0$, $p\in (2,3)$ and \begin{equation*} h_u(s)=\int^s_0\frac{\tau}{2}u^2(\tau)d\tau =\frac{1}{4\pi}\int_{B_s}u^2(x)dx \end{equation*} is the so-called Chern-Simons term, $f$ has sub-critical exponential growth $\lim_{|t|\to\infty}\frac{|f(t)|}{e^{\alpha t^2}}=0$ for every $\alpha > 0$. Under some wild assumptions on $f$, we prove the existence of a ground state solution, a mountain-pass type solution and infinitely many geometrically distinct of solutions for the above equation.

Mountain-Pass Type Solutions for the Chern–Simons–Schrödinger Equation with Zero Mass Potential and Critical Exponential Growth

Mountain-Pass Type Solutions for the Chern–Simons–Schrödinger Equation with Zero Mass Potential and Critical Exponential Growth

Importance of exponentially falling variability in heat generation on chemically reactive von kármán nanofluid flows subjected to a radial magnetic field and controlled locally by zero mass flux and convective heating conditions: A differential quadrature analysis

Owing to the various physical aspects of nanofluids as thermally enhanced working fluids and the significance of swirling flows in rheological devices as well as in the spin coating and lubrication applications, the current comprehensive examination aimed to explore the important features of spinning flows of chemically reactive Newtonian nanofluids over a uniformly revolving disk in the existence of a radially applied magnetic field along with an exponentially decaying space-dependent heat source, in the case where the disk surface is heated convectively and unaffected by the vertical nanoparticles’ mass flux. Based on feasible boundary layer approximations and Buongiorno’s nanofluid formulation, the leading coupled differential equations are stated properly in the sense of Arrhenius’s and Von Kármán’s approaches. By employing an advanced generalized differential quadrature algorithm, the obtained boundary layer equations are handled numerically with a higher order of accuracy to generate adequate graphical and tabular illustrations for the different values of the influencing flow parameters. As findings, the graphical results confirm that the nanofluid motion decelerates meaningfully thanks to the resistive magnetic influence. A significant thermal amelioration can be achieved by strengthening the magnetic impact, the generation of heat, the thermal convective process, and the thermophoresis mechanism. Moreover, it is found that the thermo-migration of nanoparticles can be reinforced more via the intensification in the convective process, the thermo-migration of nanoparticles, and the activation energy.

Hydrothermal and mass impacts of azimuthal and transverse components of Lorentz forces on reacting Von Kármán nanofluid flows considering zero mass flux and convective heating conditions

An inclusive examination has been carried out numerically to explore the multiple physical prominences of steady MHD Von Kármán's flows of chemically reacting nanofluids that can be occurred over a rotating disk in the presence of a radially applied magnetic field, in the case where the disk surface is impermeable and heated convectively, in which the vertical nanoparticles’ mass flux has vanished practically. By applying the revised Buongiorno's formulation and Von Kármán's approach, the foremost conservation equations are derived properly in the context of the boundary layer theory. By applying an efficient differential quadrature algorithm, the boundary layer equations are treated numerically to generate accurate outcomes. As upshots, it is found that the nanofluid flow slows down meaningfully with the increase in the magnetic parameter. Significant enrichment in the temperature distribution and wall nanoparticles’ molar concentration can be achieved by mounting the magnetic parameter, the Schmidt number, and the chemical reaction parameter, whereas, the Prandtl number shows a reverse trend. It bears mentioning here that the convective heating reinforces the occurrence of the thermophoresis process.

Chiral Dirac-like fermion in spin-orbit-free antiferromagnetic semimetals

Dirac semimetal is a phase of matter whose elementary excitation is described by the relativistic Dirac equation. In the limit of zero mass, its parity-time symmetry enforces the Dirac fermion in the momentum space, which is composed of two Weyl fermions with opposite chirality, to be non-chiral. Inspired by the flavor symmetry in particle physics, we theoretically propose a massless Dirac-like equation yet linking two Weyl fields with the identical chirality by assuming isospin symmetry, independent of the space-time rotation exchanging the two fields. Dramatically, such symmetry is hidden in certain solid-state spin-1/2 systems with negligible spin-orbit coupling, where the spin degree of freedom is decoupled with the lattice. Therefore, the existence of the corresponding quasiparticle, dubbed as flavor Weyl fermion, cannot be explained by the conventional (magnetic) space group framework. The 4-fold degenerate flavor Weyl fermion manifests linear dispersion and a Chern number of 2, leading to a robust network of topologically protected Fermi arcs throughout the Brillouin zone. For material realization, we show that the transition-metal chalcogenide CoNb3S6 with experimentally confirmed collinear antiferromagnetic order is ideal for flavor Weyl semimetal under the approximation of vanishing spin-orbit coupling. Our work reveals a counterpart of the flavor symmetry in magnetic electronic systems, leading to further possibilities of emergent phenomena in quantum materials.

Schrödinger–Poisson system with zero mass and convolution nonlinearity in R 2

In this paper, we prove the existence of nontrivial solutions and ground state solutions for the following planar Schrödinger–Poisson system with zero mass − Δ u + ϕ u = ( I α ∗ F ( u ) ) f ( u ) , x ∈ R 2 , Δ ϕ = u 2 , x ∈ R 2 , where α ∈ ( 0 , 2 ), I α : R 2 → R is the Riesz potential, f ∈ C ( R , R ) is of subcritical exponential growth in the sense of Trudinger–Moser. In particular, some new ideas and analytic technique are used to overcome the double difficulties caused by the zero mass case and logarithmic convolution potential.

Multiplicity of nontrivial solutions for Kirchhoff type equations with zero mass and a critical term

In this paper, a class of Kirchhoff type equations in ℝN (N ⩾ 3) with zero mass and a critical term is studied. Under some appropriate conditions, the existence of multiple solutions is obtained by using variational methods and a variant of Symmetric Mountain Pass theorem. The Second Concentration Compactness lemma is used to overcome the lack of compactness in critical problem. Compared to the usual Kirchhoff-type problems, we only require the nonlinearity to satisfy the classical superquadratic condition (Ambrosetti-Rabinowitz condition).

Nanoparticle Shapes Effects on MHD Flow of Hybrid Nanofluid over a Stretching/Shrinking Sheet with Slip and Chemical Reaction

The impact of nanoparticle shapes (i.e., blade, brick, cylindrical, platelet, and spherical) on the MHD flow of Ag-MgO/water hybrid nanofluid over a stretching/shrinking sheet is scrutinized in this study. Chemical reaction and activation energy are included in the governing partial differential equations of the flow problem. On the boundary, velocity slip and zero mass flux conditions are considered. The simplification of the governing equations and boundary conditions into non-linear ordinary differential equations is done through similarity transformation. Then, the bvp4c solver in Matlab is deployed for computation, with the results generated in the form of numerical solutions and graphs. It is found that the usage of spherical-shaped nanoparticles produces the lowest magnitude of skin friction coefficient, and the implementation of blade-shaped nanoparticles in the hybrid nanofluid provides the highest enhancement of heat transfer rate. The increment in activation energy slows down the chemical reaction that raises the concentration profile of the hybrid nanofluid. However, the concentration profile decreases as the reaction rate increases.

Multiple solutions for a class of quasilinear Schrödinger–Poisson system in $${\mathbb {R}}^3$$ with critical nonlinearity and zero mass

Multiple solutions for a class of quasilinear Schrödinger–Poisson system in $${\mathbb {R}}^3$$ with critical nonlinearity and zero mass

Theoretical analysis of modified non-Newtonian micropolar nanofluid flow over vertical Riga sheet

The main purpose of this work is to study the steady incompressible second-grade micropolar fluid flow over a nonlinear vertical stretching Riga sheet. Velocity slip and zero mass flux are considered at the solid surface of Riga shape such that the friction of nanoparticle maintains itself with strong retardation. The influence of Lorentz forces produced by the Riga plate is an important aspect of the study. The influences of thermophoresis and Brownian motion under the heat generation and e bouncy forces are studied on the nonlinear vertical Riga sheet. The mathematical model is developed under the flow assumptions. The mathematical model in terms of partial differential equations is formed by implementing the boundary layer approximations. The partial differential equations are further reduced to ordinary differential equations by means of suitable transformations. The ordinary differential equations are solved through the numerical procedure. The variations in the horizontal movement of nanofluid, thermal distribution and concentration distribution of the nanoparticle have been noted for different fluid parameters. The values of velocity profile and temperature profile are larger in the case of injection ([Formula: see text] as compared to suction ([Formula: see text]). The values of concentration distribution are smaller in the case of injection ([Formula: see text] as compared to suction ([Formula: see text]. The validation of this analysis with decay literature is provided in the form of tables.

Entropy generation minimization in the Blasius–Rayleigh–Stokes nanofluid flow through a transitive magnetic field with bioconvective microorganisms

The goal of this study is to underscore the attributes of nanofluid by discussing the Blasius-Rayleigh-Stokes (BRS) nanofluid flow with effects of modified Fourier law with gyrotactic microorganisms influenced by the transitive magnetic field past a moving semi-infinite plate. The proposed flow is supported by the non-uniform heat sink/source and radiation with zero mass flux at the surface. Analysis of entropy generation is also a part of this study. The most notable aspect of the presented model is that it discusses the entire problem using the Blasius-Rayleigh-Stokes flow. The envisioned model is reflected in the form of a system of PDEs that is transformed into a highly nonlinear system of ODEs engaging the boundary layer approximations and handled numerically. Graphical illustrations are designed for the arising parameters versus the associated profiles. It is comprehended that the thermal profile lowers for the thermal relaxation parameter. The results also disclosed that the motile density profile declines for Peclet number, and microorganism concentration difference parameter. Furthermore, the mass transfer rate is reduced by rising the chemical reaction parameter. Entropy generation upsurges versus heat generation absorption coefficients. A check for the validation of the presented model is also added to the problem.

Point-splitting regularization of the stress tensor of a coupling scalar field in de Sitter space

We perform the point-splitting regularizationon the vacuum stress tensor of a coupling scalar field in de Sitter spaceunder the guidance from the adiabatically regularized Green's function.For the massive scalar field with the minimal coupling ξ = 0,the 2nd order point-splitting regularizationyields a finite vacuum stress tensorwith a positive, constant energy density,which can be identified as the cosmological constantthat drives de Sitter inflation.For the coupling ξ ≠ 0, we find that,even if the regularized Green's function is continuous, UV and IR convergent,the point-splitting regularization does notautomatically lead to an appropriate stress tensor.The coupling ξ R causes log divergent terms,as well as higher-order finite termswhich depend upon the path of the coincidence limit.After removing these unwanted terms by extra treatments,the 2nd-order regularizationfor small couplings ξ ∈ (0,1/7.04),and respectively the 0th-order regularizationfor the conformal coupling ξ=1/6,yield a finite, constant vacuum stress tensor, in analogy to the case ξ=0.For the massless field with ξ = 0 or ξ = 1/6,the point-splitting regularizationyields a vanishing vacuum stress tensor,and there is no conformal trace anomaly for ξ = 1/6.If the 4th-order regularization were taken,the regularized energy density for general ξ would be negative,which is inconsistent with the de Sitter inflation,and the regularized Green's function would be singular at the zero mass,which is unphysical.In all these cases,the stress tensor from the point-splitting regularization is equal to that from the adiabatic one. We also discuss the issue ofthe adequate order of regularization.

Mixed convective Williamson nanofluid flow over a rotating disk with zero mass flux

AbstractThis analysis concentrates on mixed convective unsteady two‐dimensional, viscous hydro‐magnetic Williamson nanofluid flow with heat, and mass transport toward a stretchable rotating disk with suction/injection and joule heating. In addition, convective and zero mass flux conditions are implemented at the boundary to study the flow characteristics. The converted coupled nonlinear ordinary differential equations (ODEs) are tackled utilizing a semi‐analytical technique known as Optimal Homotopy Analysis Method (OHAM). The obtained outcomes are illustrated graphically to anticipate the features of the governing terms affecting the flow model. The surface skin friction, heat, and mass transport rates are deduced and discussed in detail. The validation of the present article is verified and converges to earlier published statistics. Interestingly, analysis reveals that suction/injection parameter on axial and radial velocity profiles are quite the opposite and is identical in the case of thermal and concentration buoyancy parameter. Furthermore, the Weissenberg number dominates the flow movement; the unsteady parameter lessens the momentum and thermal boundary layer (BL) thickness.

Nonsimilar modeling and numerical convective transport analysis of forced flow of radiative Carreau nanofluid with zero mass flux boundary condition

AbstractPresent research focuses on nonsimilar analysis of the flow of a non‐Newtonian Carreau nanofluid against different geometrical configurations affected by thermal radiations. The flow is induced by stretchable surface with the implementation of zero‐net mass‐flux conditions on the surface. This considered model is commonly known as Kuznetsov and Nield's proposed updated model for nanoparticles. The derived flow equations are first nondimensionalized by employing appropriate nonsimilar transformations. The transformed system is analytically tackled by employing the local nonsimilarity (LNS) approach up to the second‐truncation level in association with the numerical algorithm bvp4c. The consequences of appropriate parameters, such as the suction parameter, wedge angle parameter, Weissenberg number, Prandtl number, constant velocity parameter, temperature ratio, Brownian motion, Lewis number, thermophoresis and radiation parameters, on fluid velocity, thermal, and concentration profiles are calculated and graphed. Drag coefficient, Nusselt, and Sherwood numbers are also computed and presented in tabular form. It is observed that intensification in the suction parameter shows augmentation in the local skin friction coefficient. Enhancement in the wedge angle parameter increases both the Sherwood and Nusselt numbers. Enhancement in velocity profile of the nanofluids is noticed with the increasing estimations of suction parameter. Thermophoresis parameter enhances both thermal and concentration profiles, however increasing Lewis number leads to a decline in the concentration boundary layer. With judgment, a comparative assessment is made of the present and previous results. This research may be helpful for the researchers that are interested in studying prospective industrial and engineering nanofluid applications, notably in geophysical and geothermal systems, heat exchangers, solar water heaters, and many others.

New Directions in Modeling and Computational Methods for Complex Mechanical Dynamical Systems

This paper presents a new conceptualization of complex nonlinear mechanical systems and develops new and novel computational methods for determining their response to given applied forces and torques. The new conceptualization uses the idea of including particles of zero mass to describe the dynamics of such systems. This leads to simplifications in the development of their equations of motion and engenders a straightforward new computational approach to simulate their behavior. The purpose of the paper is to develop a new analytical and computational methodology to handle complex systems and to illustrate it through the study of an old unsolved problem in classical mechanics, that of a non-uniform rigid spherical shell rolling, without slipping, under gravity on an arbitrary dimpled bowl-shaped rigid surface. The new conceptualization provides the explicit equations of motion for the system, the analytical determination of the reaction forces supplied by the surface, and a straightforward computational approach to simulate the dynamics. Detailed analytical and numerical results are provided. The computations illustrate the complexity of the dynamical behavior of the system and its high sensitivity to the initial orientation of the shell and to the presence of any initial angular velocity normal to the surface.

Energy-Momentum Tensor Form Factors in QED

We present the results for the Energy-Momentum Tensor (EMT) form factor D(t) at one-loop accuracy in quantum electrodynamics for an electron state. We report the the results in the case of both zero and nonzero photon mass. Moreover, individual electron and photon contributions to the EMT are investigated.

A Global Minimization Trick to Solve Some Classes of Berestycki–Lions Type Problems

In this paper we show an abstract theorem that can be used to prove the existence of solution for a class of elliptic equation considered in Berestycki–Lions (Arch Ration Mech Anal 82:313–345, 1983) and related problems. Moreover, we use the abstract theorem to show that a class of zero mass problems has multiple solutions, which is a novelty for this type of problem.