Influence Of Various Physical Parameters Research Articles

Coherent Motion of Monolayer Sheets under Confinement and Its Pathological Implications.

Coherent angular rotation of epithelial cells is thought to contribute to many vital physiological processes including tissue morphogenesis and glandular formation. However, factors regulating this motion, and the implications of this motion if perturbed, remain incompletely understood. In the current study, we address these questions using a cell-center based model in which cells are polarized, motile, and interact with the neighboring cells via harmonic forces. We demonstrate that, a simple evolution rule in which the polarization of any cell tends to orient with its velocity vector can induce coherent motion in geometrically confined environments. In addition to recapitulating coherent rotational motion observed in experiments, our results also show the presence of radial movements and tissue behavior that can vary between solid-like and fluid-like. We show that the pattern of coherent motion is dictated by the combination of different physical parameters including number density, cell motility, system size, bulk cell stiffness and stiffness of cell-cell adhesions. We further observe that perturbations in the form of cell division can induce a reversal in the direction of motion when cell division occurs synchronously. Moreover, when the confinement is removed, we see that the existing coherent motion leads to cell scattering, with bulk cell stiffness and stiffness of cell-cell contacts dictating the invasion pattern. In summary, our study provides an in-depth understanding of the origin of coherent rotation in confined tissues, and extracts useful insights into the influence of various physical parameters on the pattern of such movements.

Three dimensional peristaltic flow of hyperbolic tangent fluid in non-uniform channel having flexible walls

In this present analysis, three dimensional peristaltic flow of hyperbolic tangent fluid in a non-uniform channel has been investigated. We have considered that the pressure is uniform over the whole cross section and the interial effects have been neglected. For this purpose we consider laminar flow under the assumptions of long wavelength (λ→∞) and creeping flow (Re→0) approximations. The attained highly nonlinear equations are solved with the help of Homotopy perturbation method. The influence of various physical parameters of interest is demonstrated graphically for wall tension, mass characterization, damping nature of the wall, wall rigidity, wall elastance, aspect ratio and the Weissenberg number. In this present investigation we found that the magnitude of the velocity is maximum in the center of the channel whereas it is minimum near the walls. Stream lines are also drawn to discuss the trapping mechanism for all the physical parameters. Comparison has also been presented between Newtonian and non-Newtonian fluid.

Three-Dimensional Flow of Jeffrey Nanofluid with a New Mass Flux Condition

AbstractThe three-dimensional (3D) boundary layer flow of Jeffrey nanofluid subject to the convective boundary condition is analyzed. The flow is induced by a bidirectional stretching surface. Effects of thermophoresis and Brownian motion are considered. Newly developed boundary condition with the zero nanoparticles mass flux is employed. Mathematical modeling is made under boundary layer approach. Similarity variables are used to convert the governing partial differential equations into the nonlinear ordinary differential equations. The resulting nonlinear ordinary differential equations have been solved for the velocities, temperature, and nanoparticles concentration. Graphs are plotted to examine the influence of various physical parameters on the dimensionless temperature and nanoparticles concentration distributions. Numerical values of local Nusselt number are tabulated and discussed. It is found that the effects of the Biot number on the temperature and nanoparticles concentration are quite similar...

Effect of Magnetic Field on Entropy Generation Due to Micropolar Fluid Flow in a Rectangular Duct

The entropy generation due to heat transfer, fluid friction and magnetic field has been calculated for the steady, incompressible micropolar fluid flow in a rectangular duct with constant wall temperatures. An external uniform magnetic field is applied which is directed arbitrarily in a plane perpendicular to the flow direction. The governing partial differential equations of momentum, angular momentum and energy are solved numerically using Finite difference method. The obtained velocity, microrotation and temperature distributions are then used to evaluate the entropy generation and Bejan number. Finally the graphs are presented to show the influence of various physical parameters on entropy generation rate and Bejan number.

MHD and Radiation Effects on Mixed Convection Unsteady Flow of Micropolar Fluid Over A Stretching Sheet

This present paper is concerned with the study of the magnetohydrodyamics (MHD) effects on mixed convection flow of an incompressible micropolar fluid over a stretching sheet in case of unsteady flow. Energy equation takes into account of thermal radiation. The stretching velocity is assumed to vary linearly with the distance along the sheet. Two equal and opposite forces are assumed to be impulsively applied along axial direction. The governing non-linear equations and their associated boundary conditions are first cast into a dimensionless form using local non-similarity transformations. The resulting equations are solved numerically using the Adams-Predictor Corrector method. A representative set of numerical results is displaced graphically to illustrate the influence of various physical parameters on velocity, microrotation profiles as well as the skin friction coefficient. It is found that there is a smooth transition from small-time solution to the large-time solution.

Smart Sensing Materials for Low-Cost Chipless RFID Sensor

Smart materials for chipless RFID sensors have not been developed for the broadband/high speed wireless data communication yet. Their applications are confined to some dc and very high frequency physical sensors. In this paper, various smart materials for RF sensing applications and their characteristics in the influence of various physical parameters have been analyzed. The working principle of chipless RFID sensors along with their various design and experimental results as well as their potential application is also presented. This paper provides a pathway to low cost, passive, fully printable sensor nodes for realtime condition monitoring.

MHD Flow of a Viscous Fluid over an Exponentially Stretching Sheet in a Porous Medium

Radiation effects on magnetohydrodynamic (MHD) boundary-layer flow and heat transfer characteristic through a porous medium due to an exponentially stretching sheet have been studied. Formulation of the problem is based upon the variable thermal conductivity. The heat transfer analysis is carried out for both prescribed surface temperature (PST) and prescribed heat flux (PHF) cases. The developed system of nonlinear coupled partial differential equations is transformed to nonlinear coupled ordinary differential equations by using similarity transformations. The series solutions for the transformed of the transformed flow and heat transfer problem were constructed by homotopy analysis method (HAM). The obtained results are analyzed under the influence of various physical parameters.

Linear and weakly nonlinear triple diffusive convection in a couple stress fluid layer

The effect of couple stresses on linear and weakly nonlinear stability of a triply diffusive fluid layer is investigated. Several departures not observed either in singly or doubly diffusive couple stress fluid layer have been identified while analyzing the linear stability of the problem. In contrast to the doubly diffusive couple stress fluid system, oscillatory convection is found to occur even if the diffusivity ratios are greater than unity. The presence of couple stress is to increase the threshold value of solute Rayleigh number beyond which oscillatory convection is preferred. Moreover, disconnected closed oscillatory neutral curves are identified for certain choices of physical parameters indicating the requirement of three critical values of Rayleigh number to specify the linear stability criteria instead of the usual single value. Besides, heart-shaped oscillatory neutral curves are also found to occur in some cases and the effect of couple stress parameter on some of these unusual behaviors is analyzed. A weakly nonlinear stability analysis is performed using modified perturbation technique and the stability of steady bifurcating non-trivial equilibrium solution is discussed. Heat and mass transfer are calculated in terms of Nusselt numbers and the influence of various physical parameters on the same is discussed in detail.

UNSTEADY HEAT AND MASS TRANSFER BY MHD MIXED CONVECTION FLOW OVER AN IMPULSIVELY STRETCHED VERTICAL SURFACE WITH CHEMICAL REACTION AND SORET AND DUFOUR EFFECTS

This work considers unsteady, laminar, and coupled heat and mass transfer by MHD mixed convective boundary-layer flow of an electrically conducting fluid over an impulsively stretched vertical surface in an unbounded quiescent fluid with aiding external flow in the presence of a transverse magnetic field, homogeneous chemical reaction, and Soret and Dufour effects. The stretching velocity and surface temperature and concentration are assumed to vary linearly with the distance along the surface. The flow is impulsively set into motion and both the temperature and concentration at the surface are also suddenly changed from those of the ambient fluid. The governing partial differential equations are transformed into a set of nonsimilar equations and solved numerically by an efficient implicit, iterative, finite-difference method. A parametric study illustrating the influence of various physical parameters is performed. Numerical results for the steady-state velocity, temperature, and concentration profiles as well as the time histories of the skin-friction coefficient, local Nusselt number, and local Sherwood number are presented graphically and discussed.

Reductions and solutions for the unsteady flow of a fourth grade fluid on a porous plate

The unsteady unidirectional flow of an incompressible fourth grade fluid over an infinite porous plate is studied. The flow is induced due to the motion of the plate in its own plane with an arbitrary velocity. Symmetry reductions are performed to transform the governing nonlinear partial differential equations into ordinary differential equations. The reduced equations are then solved analytically and numerically. The influence of various physical parameters of interest on the velocity profile are shown and discussed through several graphs. A comparison of the present analysis shows excellent agreement between analytical and numerical solutions.

Soret and Dufour Effects on Heat and Mass Transfer from A Continuously Moving Plate Embedded in Porous Media with Temperature Dependent Viscosity and Thermal Conductivity

A boundary layer analysis has been presented to study heat and mass transfer in the laminar, viscous, incompressible, electrically conducting, fluid past a continuously moving plate saturated in a non-Darcy porous medium in the presence of Soret and Dufour effects with temperature dependent viscosity and thermal conductivity. The governing partial differential equations are transformed into a set of similarity equations and solved numerically by shooting method. A parametric study illustrating the influence of various physical parameters is performed. Numerical results for the velocity, temperature and concentration profiles as well as the skin-friction coefficient, local Nusselt number and the local Sherwood number are presented graphically and discussed.

Melting Effect on Unsteady Hydromagnetic Flow of a Nanofluid Past a Stretching Sheet

This paper considers unsteady, laminar, boundary-layer flow with heat and mass transfer of a nanofluid along a horizontal stretching plate in the presence of a transverse magnetic field, melting and heat generation or absorption effects. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The governing partial differential equations are transformed into a set of non-similar equations and solved numerically by an efficient implicit, iterative, finite-difference method. A parametric study illustrating the influence of various physical parameters is performed. Numerical results for the steady-state velocity, temperature and nanoparticles volume fraction profiles as well as the time histories of the skin-friction coefficient, Nusselt number and the Sherwood number are presented graphically and discussed.

Asymmetries influence on critical curves of the synthetic antiferromagnetic structures in magnetic random access memory

The influence of various physical parameters on magnetizations processes of two interacting ferromagnetic particles with significance for synthetic antiferromagnetic structures as a component of the magnetic random access memory are presented. Because the real structures are not perfectly symmetric, the alterations of the perfect structure reflected in magnetization processes especially on critical curves are analyzed. The effects of the coupling constant, magnetostatic interactions and anisotropy are also analyzed.

Packed‐bed reactor for short time gas phase olefin polymerization: Heat transfer study and reactor optimization

AbstractA specially conceived packed‐bed stopped flow minireactor (3 mL) suitable for short gas phase catalytic reactions has been used to study the start‐up of ethylene homopolymerization with a supported metallocene catalyst. Focus has been put on the heat transfer characteristics of the supported catalysts and on understanding the relationship between the initial rate and the relative gas/particle velocities and the influence of particle parameters in the packed bed. We performed a comprehensive study on the influence of various physical parameters on the heat transfer regime at start up conditions. The catalyst activity as well as the polymer morphology is shown to be dependent on heat transfer regime. The knowledge thus obtained is applicable to industrial problems like catalyst injection in fluidized beds and helps preventing experimental artifacts due to overheating in following studies. © 2011 American Institute of Chemical Engineers AIChE J, 2012

Mixed convective boundary layer flow over a vertical wedge embedded in a porous medium saturated with a nanofluid: Natural Convection Dominated Regime

A boundary layer analysis is presented for the mixed convection past a vertical wedge in a porous medium saturated with a nano fluid. The governing partial differential equations are transformed into a set of non-similar equations and solved numerically by an efficient, implicit, iterative, finite-difference method. A parametric study illustrating the influence of various physical parameters is performed. Numerical results for the velocity, temperature, and nanoparticles volume fraction profiles, as well as the friction factor, surface heat and mass transfer rates have been presented for parametric variations of the buoyancy ratio parameter Nr, Brownian motion parameter Nb, thermophoresis parameter Nt, and Lewis number Le. The dependency of the friction factor, surface heat transfer rate (Nusselt number), and mass transfer rate (Sherwood number) on these parameters has been discussed.

Effects of mass transfer on free convection flow past a semi-infinite inclined plate with variable surface temperature

The unsteady free convection flow past a semi-infinite inclined plate with a variable surface temperature and mass flux is considered. The governing unsteady, two-dimensional, coupled, nonlinear integrodifferential equations are transformed into a set of non- dimensional equations that are solved numerically using an implicit finite-difference method. A representative set of the results obtained is displayed graphically to illustrate the influence of various physical parameters on the velocity, temperature, and concentration profiles. The local and average skin friction, Nusselt number, and Sherwood number are also presented.

Reversible tuning of a block-copolymer nanostructure via electric fields

Block copolymers consisting of incompatible components self-assemble into microphase-separated domains yielding highly regular structures with characteristic length scales of the order of several tens of nanometres. Therefore, in the past decades, block copolymers have gained considerable potential for nanotechnological applications, such as in nanostructured networks and membranes, nanoparticle templates and high-density data storage media. However, the characteristic size of the resulting structures is usually determined by molecular parameters of the constituent polymer molecules and cannot easily be adjusted on demand. Here, we show that electric d.c. fields can be used to tune the characteristic spacing of a block-copolymer nanostructure with high accuracy by as much as 6% in a fully reversible way on a timescale in the range of several milliseconds. We discuss the influence of various physical parameters on the tuning process and study the time response of the nanostructure to the applied field. A tentative explanation of the observed effect is given on the basis of anisotropic polarizabilities and permanent dipole moments of the monomeric constituents. This electric-field-induced effect further enhances the high technological potential of block-copolymer-based soft-lithography applications.

A Portable device to illustrate two methods for vibration reduction namely tuned dynamic absorber and isolation mounting

Mechanical vibrations can be harmful to structures as well as to humans. It is important to understand the principles of design that are used in developing various methods for reducing vibration. There are several tools at our disposal to reduce the vibrations transmitted from a vibration machine to the building structure. Two commonly available methods of vibration control are using passive vibration isolation mountings and tuned mass absorbers. This paper presents the design and working of a portable device to illustrate both methods of vibration reduction. We can examine the performance of both mounting and absorber using this physical device. The analytical and experimental work shows that such a device can effectively illustrate the principles involved in the design of mountings and absorbers. Also, the device can be used to show the influence of various physical parameters on performance. The presentation will also include the discussion on the role of such devices in enhancing the understanding of design principles in acoustics, noise, and vibration.

A Study to Investigate the Influence of Soil Properties on Suction

Abstract Various models that incorporate the influence of soil suction on different engineering properties of unsaturated soils have been developed. However, a systematic study of various physical parameters of the soil mass such as type of soil, particle size distribution, and the state of compaction (i.e., water content, dry unit weight, and saturation) is required to understand the influence of these parameters on soil suction, directly or indirectly. This would be of great help in understanding the unsaturated properties of the soil mass. With this in view, an effort has been made in this technical note to measure the suction of locally available silty soil and commercially available white clay, compacted at different water contents and dry unit weights, using an insertion tensiometer. Efforts have been made to determine the influence of various parameters, as stated earlier, on the soil suction. Details of the test setup used for these studies are also presented.

Numerical study of gas–solid flow in a precalciner using kinetic theory of granular flow

A numerical study was performed for the influence of various physical parameters on the hydrodynamics of gas–solid two-phase flow in a precalciner. An Eulerian continuum two-fluid model is applied for both the gas phase and the solid phase. The transport properties of the solid phase are represented using kinetic theory of granular flow. The unsteady gas and solid flow behavior, affected by the major concerned physical parameters in the precalciner, were presented from the computer simulations. The dilute annulus-dense core flow structure of particles was predicted. The influences of the velocities of the primary and secondary jets, secondary jet arrangement, and particle–particle coefficient of restitution on the hydrodynamics of solid flow are discussed.