20,300 research outputs found
An interactive computer code for calculation of gas-phase chemical equilibrium (EQLBRM)
A user friendly, menu driven, interactive computer program known as EQLBRM which calculates the adiabatic equilibrium temperature and product composition resulting from the combustion of hydrocarbon fuels with air, at specified constant pressure and enthalpy is discussed. The program is developed primarily as an instructional tool to be run on small computers to allow the user to economically and efficiency explore the effects of varying fuel type, air/fuel ratio, inlet air and/or fuel temperature, and operating pressure on the performance of continuous combustion devices such as gas turbine combustors, Stirling engine burners, and power generation furnaces
Unconventional Quantum Critical Points
In this paper we review the theory of unconventional quantum critical points
that are beyond the Landau's paradigm. Three types of unconventional quantum
critical points will be discussed: (1). The transition between topological
order and semiclassical spin ordered phase; (2). The transition between
topological order and valence bond solid phase; (3). The direct second order
transition between different competing orders. We focus on the field theory and
universality class of these unconventional quantum critical points. Relation of
these quantum critical points with recent numerical simulations and experiments
on quantum frustrated magnets are also discussed.Comment: 28 pages, 6 figures. Review article for Int. J. Mod. Phys.
Final state interactions in two-particle interferometry
We reconsider the influence of two-particle final state interactions (FSI) on
two-particle Bose-Einstein interferometry. We concentrate in particular on the
problem of particle emission at different times. Assuming chaoticity of the
source, we derive a new general expression for the symmetrized two-particle
cross section. We discuss the approximations needed to derive from the general
result the Koonin-Pratt formula. Introducing a less stringent version of the
so-called smoothness approximation we also derive a more accurate formula. It
can be implemented into classical event generators and allows to calculate FSI
corrected two-particle correlation functions via modified Bose-Einstein
"weights".Comment: 12 pages RevTeX, 2 ps-figures included, submitted to Phys. Rev.
Balancing Local Order and Long-Ranged Interactions in the Molecular Theory of Liquid Water
A molecular theory of liquid water is identified and studied on the basis of
computer simulation of the TIP3P model of liquid water. This theory would be
exact for models of liquid water in which the intermolecular interactions
vanish outside a finite spatial range, and therefore provides a precise
analysis tool for investigating the effects of longer-ranged intermolecular
interactions. We show how local order can be introduced through quasi-chemical
theory. Long-ranged interactions are characterized generally by a conditional
distribution of binding energies, and this formulation is interpreted as a
regularization of the primitive statistical thermodynamic problem. These
binding-energy distributions for liquid water are observed to be unimodal. The
gaussian approximation proposed is remarkably successful in predicting the
Gibbs free energy and the molar entropy of liquid water, as judged by
comparison with numerically exact results. The remaining discrepancies are
subtle quantitative problems that do have significant consequences for the
thermodynamic properties that distinguish water from many other liquids. The
basic subtlety of liquid water is found then in the competition of several
effects which must be quantitatively balanced for realistic results.Comment: 8 pages, 6 figure
The Quark-Gluon Plasma in a Finite Volume
The statistical mechanics of quarks and gluons are investigated within the
context of the canonical ensemble. Recursive techniques are developed which
enforce the exact conservation of baryon number, total isospin, electric
charge, strangeness, and color. Bose and Fermi-Dirac statistics are also
accounted for to all orders. The energy, entropy and particle number densities
are shown to be significantly reduced for volumes less than 5 cubic fm.Comment: 8 pages, 3 figure
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