High resolution data on low energy phonon branches (acoustic and soft optic) along the three principal symmetry axes in pure KTaO3 were obtained by cold neutron inelastic scattering between 10 and 80 K. Additional off-principal axis measurements were performed to characterize the dispersion anisotropy (away from the <100> and <110> axes). The parameters of the phenomenological model proposed by...

The temperature dependence of the Casimir force between a real metallic plate and a metallic sphere is analyzed on the basis of optical data concerning the dispersion relation of metals such as gold and copper. Realistic permittivities imply, in accordance with basic thermodynamic considerations, that the transverse electric zero mode does not contribute. This results in observable differences ...

The self-consistent phonon (SCP) theory is used to study the dynamics of monolayers of xenon, krypton, and methane adsorbed on graphite. Only the ~3Xv 3 sohd phase is considered. It is shown that the phonon energies of the Xe monolayers are very similar to those of their Soating counterparts, while the interaction of the Kr and CH4 monolayers vnth the graphite signNcantly a8ects the phonon disp...

In this article, a MATLAB program for a three-dimensional simulation of multipollutants (CO, NOx, SO2, and TH) dispersion from an industrial stack using a Multiple Cell Model is presented. The program verification was conducted by checking the simulation results against experimental data and Gaussian Model and better agreements were obtained in comparison with the Gaussian model. The effects of...

Calcium phosphate materials have been used increasingly in the past 40 years as bone graft substitutes in the dental and orthopedic fields. Accordingly, numerous fabrication methods have been proposed and used. However, the controlled production of spherical calcium phosphate particles remains a challenge. Since such particles are essential for the synthesis of pastes and cements delivered into...

I present the detailed behavior of phonon dispersion curves near momenta which span the electronic Fermi sea in a superconductor. I demonstrate that an anomaly, similar to the metallic Kohn anomaly, exists in a superconductor’s dispersion curves when the frequency of the phonon spanning the Fermi sea exceeds twice the superconducting energy gap. This anomaly occurs at approximately the same mom...

Nano-ZnO was prepared by direct precipitation method with zinc chloride and sodium carbonate anhydrous as raw materials, and its particle size and dispersion were characterized by TEM. The effects of concentration and the ratio of reactants and reaction temperature on its dispersion in aqueous solution were analyzed and the best reaction conditions were as follows: reaction temperature 60 , ult...

The problem of hydrodynamic dispersion in non-Darcy free convection heat and mass transfer from vertical surface embedded in a porous medium has been presented. The Forchheimer extension is considered in the flow equations. The flow, temperature and concentration fields in Darcy and non-Darcy porous media are observed to be governed by complex interactions among the diffusion rate Le, buoyancy ...

Applicators have long recognized that temperature inversions dramatically influence the behavior of pesticide material released into the atmosphere during pesticide application. This behavior can be explained in terms of the relationship between vertical atmospheric temperature gradients (stability) and atmospheric mixing (turbulence). This relationship is not intuitively obvious, but once it i...

This paper investigates the influence of double dispersion and viscosity on natural convection heat and mass transfer from vertical cone in a non-Darcy porous medium saturated with non-Newtonian fluid. The surface of the cone and the ambient medium are maintained at constant but different levels of temperature and concentration. The Ostwald-de Waele power law model is used to characterize the n...