Let f : [0,+∞) −→ (0,+∞) be a sufficiently smooth convex function, vanishing at infinity. Consider the planar domain Q delimited by the positive x-semiaxis, the positive y-semiaxis, and the graph of f . Under certain conditions on f , we prove that the billiard flow in Q has a hyperbolic structure and, for some examples, that it is also ergodic. This is done using the cross section correspondin...

Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate (SDS), and cationic hexadecyltrimethylammonium bromide (CT...

An aqueous diluent containing Tween 60 and Arlacel 80 gave greater recovery of microorganisms when compared with two common diluents as determined by aerobic plate count of inoculated anhydrous cosmetics. The greater recovery was caused by better dispersion of the anhydrous cosmetics in the diluents.

This paper develops a model of the geographic distribution of crime in an urban area. Agents select their occupation, residence, consumption, and housing. The paper is the first to formally study how the location of crime, the residence of workers, and housing prices are affected by the spatial allocation of police protection. It examines two opposite strategies of police deployment: concentrat...

An adjuvant is any material added to a herbicide spray solution to enhance or modify the performance of the solution. Adjuvants can be divided into two general categories: spray modifiers and activators (Kirkwood, 1994). Spray modifiers are those adjuvants that change the wetting, spreading or sticking characteristics of the spray solution. This is primarily accomplished by a modification in th...

This work is devoted to 2D dispersing billiards with smooth boundary, i.e. periodic Lorentz gases (with and without horizon). We revisit several fundamental properties of these systems and make a number of improvements. The necessity of such improvements became obvious during our recent studies of gases of several particles [CD]. We prove here that local (stable and unstable) manifolds, as well...