We have recently discussed the correct form of the dispersion relation for electrostatic waves in inhomogeneous plasmas, considering for simplicity the particular case in which the magnetic field is homogeneous and other plasma parameters can be inhomogeneous, and deriving a general expression for the dielectric constant, valid for arbitrary direction of propagation [1-3] The situation in which...

Using data from one of the Internet’s leading price comparison sites for consumer electronics products, we present evidence for the persistence of price dispersion for 36 homogeneous products. The markets for these products are “thick” with an average of over 20 firms selling each product. We show that prices do not converge to the “law of one price” even after an 18 month period. This finding ...

Low-temperature solution processible and solventless silica-epoxy hybrid materials composed of organically modified silica nanoparticles and epoxy monomers were successfully fabricated through simple sol-gel process and solvent evaporation. These silica-epoxy hybrid materials exhibited the homogeneous dispersion without any phase separation, aggregation, and gelation in the solventless environm...

Analytical models require significant simplification of the real-world system, especially in the case of solute transport in subsurface groundwater. This article presents an analytical study of one-dimensional non-reactive solute transport in a homogeneous finite porous medium. The governing advection-dispersion equation, which includes retardation factor, is included for solute transport. The ...

Acoustoelasticity, or the change in elastic wave speeds with stress, is a well-studied phenomenon for bulk waves. The effect of stress on Lamb waves is not as well understood, although it is clear that anisotropic stresses will produce anisotropy in the Lamb wave dispersion curves. Here the theory of acoustoelastic Lamb wave propagation is developed for isotropic media subjected to a biaxial, h...

We describe methods of investigating the behavior of photonic crystals. Our approach establishes a link between the dispersion relation of the Bloch modes for an infinite crystal (which describes the intrinsic properties of the photonic crystal in the absence of an incident field) and the diffraction problem of a grating (finite photonic crystal) illuminated by an incident field. We point out t...

Tungsten catalysts supported on activated carbon were prepared using tungsten hexacarbonyl, ammonium tungstate, and tungsten pentaethoxide. The catalysts were pretreated in He, dry air, or wet air at 623 K for 6 h before being characterized by N2 adsorption at 77 K, temperature-programmed desorption, X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron sp...

In the present research, the aqueous suspensions of nano-sized YSZ particles were prepared using a common and available dispersant (Dolapix CE64) at different pH values and their stability were evaluated through the sedimentation height, viscosity measurement, and microstructural observation. Different amounts of dispersant were tested and the optimum percentage was examined by measuring the vi...

This paper examines the structure of wages in a very specific labor market: care assistants in residential homes for the elderly on England's "sunshine coast." This sector corresponds closely to economists' notion of what should be a competitive labor market, both because it has a large number of small firms undertaking a very homogeneous activity in a concentrated geographical area, and becaus...

We derive a general formulation of the time domain random walk (TDRW) approach to model the hydrodynamic transport of inert solutes in complex geometries and heterogeneous media. We demonstrate its formal equivalence with the discretized advection-dispersion equation and show that the TDRW is equivalent to a continuous time random walk (CTRW) characterized by space-dependent transition times an...