The Confined Lennard-Jones Two Piston System simulates a constant-energy two-dimensional system of particles confined by two frictionless pistons of equal mass M. This computer model complements theoretical work describing the adiabatic expansion of an ideal gas using the quasi-static approximation. Users can set the initial particle kinetic energy, Lennard Jones parameters, and the initial particle separation. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. The time evolution of temperature, pressure, and piston speed are shown in a second window.
Particles in this model have unit mass and interact through pairwise Lennard-Jones forces and hard-wall contact forces. The instantaneous temperature is computed using the average particle kinetic energy and the pressure is computed using the virial expansion.
The Confined Lennard-Jones Two Piston System is a supplemental simulation for the article "Evolution of ideal gas mixtures confined in an insulated container by two identical pistons" by Joaquim Anacleto, Joaquim Alberto C. Anacleto, and J. M. Ferreira in the American Journal of Physics 79(10), 1009-1014 (2011) and has been approved by the authors and the American Journal of Physics (AJP) editor. The Confined Lennard-Jones Two Piston System was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_md_ConfinedLennardJonesTwoPistonSystem.jar file will run the program if Java is installed.
Please note that this resource requires
at least version 1.5 of
6-8: 4E/M4. Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves.
AAAS Benchmark Alignments (1993 Version)
4. THE PHYSICAL SETTING
E. Energy Transformations
4E (9-12) #2. Heat energy in a material consists of the disordered motions of its atoms or molecules. In any interactions of atoms or molecules, the statistical odds are that they will end up with less order than they began?that is, with the heat energy spread out more evenly. With huge numbers of atoms and molecules, the greater disorder is almost certain.
Christian, W. (2011). Confined Lennard-Jones Two Piston System Model (Version 1.0) [Computer software]. Retrieved November 28, 2015, from http://www.compadre.org/Repository/document/ServeFile.cfm?ID=10836&DocID=2190
%0 Computer Program %A Christian, Wolfgang %D March 10, 2011 %T Confined Lennard-Jones Two Piston System Model %7 1.0 %8 March 10, 2011 %U http://www.compadre.org/Repository/document/ServeFile.cfm?ID=10836&DocID=2190
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