Comment on "Head-on collision of electron acoustic solitary waves in a plasma with nonextensive hot electrons"

In a recent paper "Head-on collision of electron acoustic solitary waves in a plasma with nonextensive hot electrons" [Astrophys. Space Sci. 338, 271-278 (2012)] Eslami, Mottaghizadeh and Pakzad deal with the problem of the head-on collisions between two weakly nonlinear electron-acoustic solitary waves. Unfortunately, their treatment is deficient and leads to erroneous conclusions.Comment: Accepted for publication in "Astrophysics and Space Science

Small fuel cell to eliminate pressure caused by gassing in high energy density batteries Progress report, 30 Sep. - 30 Dec. 1965

Miniature fuel cells to eliminate pressure caused by gassing in sealed silver-zinc batterie

Small fuel cell to eliminate pressure caused by gassing in high energy density batteries Final report, 30 Jun. 1965 - 30 Jun. 1966

Gas pressure reduction in silver-zinc batteries by installing miniature hydrogen-oxygen fuel cel

Small fuel cell to eliminate pressure caused by gassing in high energy density batteries Progress report, 30 Dec. 1965 - 31 Mar. 1966

Miniature fuel cell as pressure regulators in silver-zinc batterie

Small fuel cell to eliminate pressure caused by gassing in high energy density batteries Progress report, 30 Jun. - 30 Sep. 1965

Miniature fuel cells as proposed solution to gassing and pressure rise problems in sealed silver-zinc batterie

Trace functions as Laplace transforms

We study trace functions on the form t\to\tr f(A+tB) where $f$ is a real function defined on the positive half-line, and $A$ and $B$ are matrices such that $A$ is positive definite and $B$ is positive semi-definite. If $f$ is non-negative and operator monotone decreasing, then such a trace function can be written as the Laplace transform of a positive measure. The question is related to the Bessis-Moussa-Villani conjecture. Key words: Trace functions, BMV-conjecture.Comment: Minor change of style, update of referenc

Some Calculable Contributions to Entanglement Entropy

Entanglement entropy appears as a central property of quantum systems in broad areas of physics. However, its precise value is often sensitive to unknown microphysics, rendering it incalculable. By considering parametric dependence on correlation length, we extract finite, calculable contributions to the entanglement entropy for a scalar field between the interior and exterior of a spatial domain of arbitrary shape. The leading term is proportional to the area of the dividing boundary; we also extract finite subleading contributions for a field defined in the bulk interior of a waveguide in 3+1 dimensions, including terms proportional to the waveguide's cross-sectional geometry; its area, perimeter length, and integrated curvature. We also consider related quantities at criticality and suggest a class of systems for which these contributions might be measurable.Comment: 4+ pages, 1 figure. v2: Some clarifications and more references; updated to resemble version published in PR

Do Binary Hard Disks Exhibit an Ideal Glass Transition?

We demonstrate that there is no ideal glass transition in a binary hard-disk mixture by explicitly constructing an exponential number of jammed packings with densities spanning the spectrum from the accepted ``amorphous'' glassy state to the phase-separated crystal. Thus the configurational entropy cannot be zero for an ideal amorphous glass, presumed distinct from the crystal in numerous theoretical and numerical estimates in the literature. This objection parallels our previous critique of the idea that there is a most-dense random (close) packing for hard spheres [Torquato et al, Phys. Rev. Lett., 84, 2064 (2000)].Comment: Submitted for publicatio

Detecting and diagnosing faults in dynamic stochastic distributions using a rational b-splines approximation to output PDFs

Describes the process of detecting and diagnosing faults in dynamic stochastic distributions using a rational b-splines approximation to output PDFs