Carleman estimates for stratified media

We consider anisotropic elliptic and parabolic operators in a bounded stratified media in Rn characterized by discontinuities of the coefficients in one direction. The surfaces of discontinuities cross the boundary of the domain. We prove Carleman estimates for these operators with an arbitrary observation region.     

Fat crystals and water-in-oil emulsion stability

Products such as cosmetics, pharmaceuticals, and crude oil often exist as water-in-oil (W/O) emulsions during their processing or in final form. In many cases, their dispersed aqueous phase is encased in a crystal network and/or by interfacially-adsorbed (‘Pickering’) particles [paraffins, triacylglycerols, polymers, etc.] that promote emulsion kinetic stability by hindering droplet–droplet contact, coalescence and macroscopic phase separation. In processed foods, important questions remain regarding whether a continuous phase fat crystal network or Pickering crystal provides better stabilization. This review explores the following factors related to crystal-stabilized W/O emulsions: i) the key properties dictating fat crystal spatial distribution (at the interface or in the continuous phase); ii) how temperature and freeze–thaw emulsion destabilization are intimately linked with fat crystal spatial distribution, and; iii) why oil-soluble surfactant interactions with the continuous oil phase influence fat crystal wettability and emulsifier efficacy. It is shown that these parameters strongly govern W/O emulsion formation and stability.     

A column generation approach for location-routing problems with pickup and delivery

In this paper we formulate an integer programming model for the Location and Routing Problem with Pickup and Delivery. We propose a column generation scheme and implement, for the subproblem, a label-setting algorithm for the shortest path with pickup and delivery and time windows problem. We also propose a set of heuristics to speed up this process. To validate the model, we implement the column generation scheme and test it on different instances developed in this paper. We also provide an analysis of how the costs of opening depots and the fixed cost of routes affect the optimal solution.     

An effective non-Archimedean anti-degeneracy/cycling linear programming method especially for data envelopment analysis and like models

A non-Archimedean effective anti-degeneracy/cycling method for linear programming models, especially Data Envelopment Analysis (DEA), processing networks and advertising media mix models is herein developed. It has given a tenfold speed increase plus elimination of cycling difficulties over conventional Marsden or Kennington/Ali LP software modules in a 1000 LP DEA application.     

3D Modeling of amplification processes in CPA laser amplifiers

We present here chirped pulse amplification simulations allowing for the extension of the generally used 1D model. The importance of the beam spatial profiles, diffraction and thermal effects in simulations is clearly shown in order to describe with accuracy the gain saturation. Experimental measurements performed on a 100 TW laser validate this calculation. The effects of dispersion and self-focusing are also studied.This revised version was published online in August 2005 with a corrected cover date.     

Lattice dynamics and debye-waller factor near the 195 K phase transition in RbCaF3

The experimental temperature dependence of the mean square amplitudes of atoms in RbCaF₃ is compared with the theoretical values calculated from both an harmonic and a quasi rigid ion model. In the light of these results the anhamonicity of the cubic phase is discussed.     

Brillouin scattering investigation of the structural phase transition of TlCdF3 and RbCaF3

The elastic constants of the fluoroperovskites TlCdF₃ and RbCaF₃ have been investigated by means of Brillouin scattering. Elastic and attenuation anomalies have been observed very near the phase transition temperature for longitudinal and transverse acoustic waves.