We study the dynamics of three particles in a finite interval, in which two light particles are separated by a heavy "piston," with elastic collisions between particles but inelastic collisions between the light particles and the interval ends. A symmetry breaking occurs in which the piston migrates near one end of the interval and performs small-amplitude periodic oscillations on a logarithmic...

T Background:Background: Clogging of biliary stents remains an important problem. In vitro studiess have shown less sludge formation in Teflon stents. Recently, clinical studies with Teflonn stents have produced contradictory results. The aim of this study was to investigatee whether the surface properties of the endoprostheses could explain the variationn observed in clinical studies. Methods:...

The piston problem is investigated in the case where the length of the cylinder is infinite (on both sides) and the ratio m/M is a very small parameter, where m is the mass of one particle of the gaz and M is the mass of the piston. Introducing initial conditions such that the stochastic motion of the piston remains in the average at the origin (no drift), it is shown that the time evolution of...

We study a heavy piston that separates finitely many ideal gas particles moving inside the unit interval. Using averaging techniques, we prove precise rates of convergence of the actual motions of the piston to its averaged behavior. The convergence is uniform over all initial conditions in a compact set. The results extend earlier work by Sinai and Neishtadt, who determined that the averaged b...

We present a simple method for fabricating chemically-inert Teflon microfluidic valves and pumps in glass microfluidic devices. These structures are modeled after monolithic membrane valves and pumps that utilize a featureless polydimethylsiloxane (PDMS) membrane bonded between two etched glass wafers. The limited chemical compatibility of PDMS has necessitated research into alternative materia...

The paper presents the study of a new compressor for household appliances, developed through a virtual simulation system, with Simulink and Adams software. Linear compressor has a linear motor coupled to a mechanical system: a piston and a spring. The advantage of this compressor respect to a standard reciprocating compressor is due to the high reduction of energy losses and variable capacity p...

The Periodic Mobile Piston Pump Unit Routing Problem consists of, given a set of surface oil wells scattered over an onshore producing field, determining routes for each day of work, with limited duration work shift, that maximize the collection of oil carried by a mobile piston pump unit. This paper presents different construction and local search methods used in the composition of GRASP and I...

This paper introduces the high efficiency of a horizontal rolling piston type compressor for household refrigerators. In the rolling piston type compressor, excessive compression loss and leakage loss largely affects the efficiency of the compressor. An experimental analysis of the following three items was made to determine that the performance characteristics of the compressor could be improv...