We describe the effects of both magnetic buoyancy and differential rotation on a disc of isothermal gas embedded in a purely azimuthal magnetic field, in order to study the evolution and interplay of Parker and shearing instabilities. We perform a linear analysis of the evolution of perturbations in the shearing sheet model. Both instabilities occur on the slow MHD branch of the dispersion rela...

We consider two perfectly smooth featureless surfaces at T = 0, defined only by their respective dielectric functions, separated by a finite distance, and ask the question of whether they can experience any friction when sheared parallel to their interface. We find large frictional effects comparable to everyday frictional forces provided that the materials have resistivities of the order of 1 ...

I discuss the results of simplified three dimensional magnetohydrodynamic simulations of the boundary layer between a disc and a non-rotating, unmagnetized star. Strong magnetic fields, possibly approaching equipartition with the thermal energy, occur in the boundary layer due to the shearing of disc-generated fields. The mean boundary layer magnetic field, which is highly variable on an orbita...

The first direct experimental evidence of the suppression of quasi-two-dimensional turbulence by mean flows is presented. The flow either is induced externally or appears in the process of spectral condensation due to an inverse cascade in bounded turbulence. The observed suppression of large scales is consistent with an expected reduction in the correlation time of turbulent eddies due to shea...

Particle heating in advection-dominated accretion flows (ADAFs) by nonlinear MHD (Alfvénic) turbulence is investigated. Such turbulence with highly-fluctuating magnetic fields, B̃ ∼ B0, is believed to be naturally produced by the magnetic shearing instability near the nonlinear saturation. It is shown that the energy is dissipated in the parallel cascade, which occurs due to nonlinear compressib...

We examine the development of a transient spiral arm in a disk galaxy made up of both gas and stars. To this end we have performed numerical simulations in a shearing sheet (basically a rectangular patch of a disc) that contains gas in the form of clouds behaving like Brahic’s (1977) sticky particles, and stars that appear as a background continuum providing the perturbation forces. These are c...

Abstract: This paper describes a shearing interferometer with four diffraction gratings for dividing light waves. It allows us to use an extended white light source. This feature of the interferometer is discussed and demonstrated by experiments. By constructing the interferometer for testing transparent object, phase distribution of the light wave passing through an optical lens is measured wi...

The synthesis, structure, and photophysical properties of a new family of trinuclear CuRe(2) chromophore-quencher complexes having the general form [Cu(pyacac)(2)(Re(bpy')(CO)(3))(2)](OTf)(2) (where pyacac = 3-(4-pyridyl)-acetylacetonate and bpy' = 4,4'-5,5'-tetramethyl-2,2'-bipyridine (tmb, 1), 4,4'-dimethyl-2,2'-bipyridine (dmb, 2), 2,2'-bipyridine (bpy, 3), 4,4'-dichloro-2,2'-bipyridine (dcl...

A linear knife grid device was developed for first-stage size reduction of high- and low-moisture switchgrass (Panicum virgatum L.), a tough, fibrous perennial grass being considered as a feedstock for bioenergy. The size reduction is by a shearing action accomplished by forcing a thick packed bed of biomass against a grid of sharp knives. The system is used commercially for slicing forages for...

Digital shearograohy has demonstrated great potential in revealing defects in objects especially in detecting delaminations in composite materials. It is gaining more and more acceptance by automotive and aerospace industries in the field of nondestructive testing (NDT) of composite materials. A key optical component used in shearography is a shearing device in which the shearing amount, sheari...