A temperature-compensated material of fiber Bragg grating (FBG), which has negative thermal -expansion coefficient has been presented. The temperature coefficient of FBGs’ center wavelength is less than 0.0005 nm/°C after three-layer-structure temperature-compensated package under tension. For the first time, PMD of FBG with and without temperature compensation has been detailedly studied and m...

The combined effect of non-Newtonian rheology and irreversible boundary reaction on dispersion in a Herschel-Bulkley fluid through a conduit (pipe/channel) is studied by using generalized dispersion model. The study explains the development of dispersive transport following the injection of a tracer in terms of three effective transport coefficients namely exchange, convective and dispersion co...

We propose a purely phase-sampled Bragg grating for dispersion and dispersion slope compensation by introducing a chirp in the grating period and coupling coefficient. The bandwidth of all reflected channels can be equalized by chirping the sampling period at the same time. We show that a trade-off exists between the linearity of dispersion slope and the equalization of reflection channel bandw...

A mathematical model presented in this paper describes the dispersion and concentration ofcontaminants (fine and coarse) in porous medium with the effect of chemical reaction. Solutetransport in porous media is discussed by means of advection-dispersion equation. The effectof particle mass parameter and reaction rate parameter on the dispersion coefficient and meanconcentration of a chemical so...

The Sound attenuation and dispersion in saturated gas-vapor-droplet mixture in the presence of evaporation has been investigated theoretically. The theory is based on an extension of the work of Davidson (1975) to accommodate the effects of nonlinear particle relaxation processes of mass, momentum and energy transfer on sound attenuation and dispersion. The results indicate the existence of a s...

The van der Waals coefficients, C6 , C8, and C10 for the alkali-metal ~Li, Na, K, and Rb! and alkaline-earthmetal ~Be, Mg, Ca, and Sr! atoms are estimated by a combination of ab initio and semiempirical methods. Polarizabilities and atom-wall coefficients are given as a diagnostic check, and the lowest order nonadiabatic dispersion coefficient, D8 and the three-body coefficient, C9 are also pre...

[1] We present a theory for dynamic longitudinal dispersion coefficient (D) for transport by Poiseuille flow, the foundation for models of many natural systems, such as in fractures or rivers. Our theory describes the mixing and spreading process from molecular diffusion, through anomalous transport, and until Taylor dispersion. D is a sixth order function of fracture aperture (b) or river widt...

Dye diffusion study to obtain the horizontal diffusivity is often carried now a day. Data obtained by Indomer coastal hydraulics by conducting dye tracing experiments at several parts of coastal India, were used and have been analyzed to estimate horizontal mixing coefficients. The data of these studies are used to find out the dispersion coefficients and the oceanic diffusivity is reviewed. An...

We study interaction between two solitons from different frequency channels propagating in an optical fiber. The interaction may be viewed as an inelastic collision, in which energy is lost to continuous radiation due to small but finite third order dispersion. We develop a perturbation theory with two small parameters: the third order dispersion coefficient d(3), and the reciprocal of the inte...

The aim of this work was to determine the hydrodynamic dispersion coefficient at different interstitial velocities for its application in a mass transport model to predict heavy metal biosorption onto Posidonia oceanica and peat. Tracing experiments with lithium chloride (LiCl) were performed in biosorbent packed beds of 10 and 27 cm length and flow rates between 10 and 100 cm 3 h −1 . Hydrodyn...