Enhanced heat transfer in H2O inspired by Al2O3 and γAl2O3 nanomaterials and effective nanofluid models

Currently, thermal improvement in the nanofluids over a curved Riga sheet is a topic of interest and attained popularity among the researchers. Therefore, the colloidal suspension of water suspended by [Formula: see text] and [Formula: see text] over a curved Riga surface is modeled for the heat transfer analysis. The nondimensionalization of the model is accomplished via invertible variables. On the basis of dynamic viscosities and thermal conductivities of [Formula: see text] and [Formula: see text] nanoparticles, two nanofluid models developed over a semi-infinite region. Then, the models solved numerically and found graphical results for the flow characteristics, thermophysical properties and local thermal performance rate by altering the pertinent flow parameters. It is examined that the fluid motion rapidly decreases for [Formula: see text] and momentum boundary layer region decreases. The squeezed and curvature parameters lead to reduce in the nanofluid velocity. The temperature of more magnetized enhances significantly. Thermophysical characteristics of the nanofluids enhance for higher volumetric fraction factor. More heat transfer at the Riga surface for higher M and R.

Stokes Equation in a Semi-Infinite Region: Generalization of the Lamb Solution and Applications to Marangoni Flows

We consider the creeping flow of a Newtonian fluid in a hemispherical region. In a domain with spherical or nearly spherical geometry, the solution of the Stokes equation can be expressed as a series of spherical harmonics. However, the original Lamb solution is not complete when the flow is restricted to a semi-infinite space. The general solution in hemispherical geometry is then constructed explicitly. As an application, we discuss the solutions of Marangoni flows due to a local source at the liquid–air interface.

A Note on Kant’s First Antinomy

An interpretation of Kant’s first antinomy is defended whereby both its thesis and its antithesis depend on a common basic principle that Kant endorses, namely that there cannot be an ‘infinite contingency’, by which is meant a contingent fact about how an infinite region of space or time is occupied. The greatest problem with this interpretation is that Kant explicitly declines to apply counterparts of the temporal arguments in the antinomy to the world’s future, even though, if the interpretation is correct, such arguments are clearly there to be applied. This problem, it is argued, is surmountable.

Ordering of Rods near Surfaces: Concentration Effects

We study the orientation of rods in the neighborhood of a surface. A semi-infinite region in two different situations is considered: (i) the rods are located close to a flat wall and (ii) the rods occupy the space that surrounds a sphere. In a recent paper we investigated a similar problem: the interior of a sphere, with a fixed concentration of rods. Here, we allow for varying concentration, the rods are driven from a reservoir to the neighborhood of the surface by means of a tunable chemical potential. In the planar case, the particle dimensions are irrelevant. In the curved case, we consider cylinders with dimensions comparable to the radius of curvature of the sphere; as they come close to the surface, they have to accommodate to fill the available space, leading to a rich orientational profile. These systems are studied by a mapping onto a three-state Potts model with annealed disorder on a semi-infinite lattice; two order parameters describe the system: the occupancy and the orientation. The Hamiltonian is solved using a mean-field approach producing recurrence relations that are iterated numerically and we obtain various interesting results: the system undergoes a first order transition just as in the bulk case; the profiles do not have a smooth decay but may present a step and we search for the factors that determine their shape. The prediction of such steps may be relevant in the field of self-assembly of colloids and nanotechnology.