24 research outputs found
Constraints from orbital motions around the Earth of the environmental fifth-force hypothesis for the OPERA superluminal neutrino phenomenology
It has been recently suggested by Dvali and Vikman that the superluminal
neutrino phenomenology of the OPERA experiment may be due to an environmental
feature of the Earth, naturally yielding a long-range fifth force of
gravitational origin whose coupling with the neutrino is set by the scale M_*,
in units of reduced Planck mass. Its characteristic length lambda should not be
smaller than one Earth's radius R_e, while its upper bound is expected to be
slightly smaller than the Earth-Moon distance (60 R_e). We analytically work
out some orbital effects of a Yukawa-type fifth force for a test particle
moving in the modified field of a central body. Our results are quite general
since they are not restricted to any particular size of lambda; moreover, they
are valid for an arbitrary orbital configuration of the particle, i.e. for any
value of its eccentricity . We find that the dimensionless strength coupling
parameter alpha is constrained to |alpha| <= 1 10^-10-4 10^-9 for 1 R_e <=
lambda <= 10 R_e by the laser data of the Earth's artificial satellite LAGEOS
II, corresponding to M_* >= 4 10^9 -1.6 10^10. The Moon perigee allows to
obtain |alpha| <= 3 10^-11 for the Earth-Moon pair in the range 15 R_e <=
lambda = 3 10^10 - 4.5 10^10. Our results
are neither necessarily limited to the superluminal OPERA scenario nor to the
Dvali-Vikman model, in which it is M_* = 10^-6 at lambda = 1 R_e, in contrast
with our bounds: they generally extend to any theoretical scenario implying a
fifth-force of Yukawa-type.Comment: LaTex2e, 18 pages, 4 figures, 1 table, 81 reference
Possible variations of the fine structure constant and their metrological significance
We briefly review the recent experimental results on possible variations of
the fine structure constant on the cosmological time scale and its
position dependence. We outline the theoretical grounds for the assumption that
might be variable, mention some phenomenological models incorporating
a variable into the context of modern cosmology and discuss the
significance of possible variations for theoretical and practical
metrology.Comment: Latex, 17 pages, brief review. References updated, minor errors
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Theoretical Investigation of the Structure and Physicochemical Properties of Alkaline and Alkaline Earth Metal Perchlorate Solutions in Sulfolane
To assess the possibility of using solutions of perchlorates
of
alkali and alkaline earth metals in sulfolane as electrolytes for
electrochemical energy storage devices with metal negative electrodes,
the physicochemical properties of 0.5 M solutions of Me(ClO4)n (Me = Li, Na, K, Mg, and Ca) in sulfolane
were simulated by the method of molecular dynamics. The density, viscosity,
conductivity, self-diffusion coefficients, and transport numbers are
calculated. Satisfactory agreement between the calculated and experimentally
measured properties of 0.5 M solutions of LiClO4 and NaClO4 in sulfolane suggests that the calculated values of the physicochemical
properties of solutions of K, Mg, and Ca perchlorates are also close
to real values. The study of the structure of solvate complexes of
salts of alkali and alkaline earth metals with sulfolane by quantum
chemical and molecular dynamics modeling showed that the first solvate
shell of metal cations consists of sulfolane molecules. Regardless
of the nature of the cation, sulfolane is coordinated to the metal
cation by only one oxygen atom. Based on the analysis of the calculated
values of the physicochemical properties of solutions of metal perchlorates
in sulfolane, it can be concluded that they can be used as electrolyte
systems of electrochemical energy storage devices with negative electrodes
made of alkali and alkaline earth metals
LUMINESCENCE OF ALUMINUM OXIDE FILMS AND PERSPECTIVES OF THEIR APPLICATION IN NANOPHOTONICS PLANAR MICROSTRUCTURES
Various methods of fabrication the luminescent film structures based on porous anodic alumina are analyzed. Manufacturing of luminescent structures by anodizing aluminum in oxalic acid allows observation of visible to the naked eye photoluminescence in the blue range, which remains under ambient conditions for a year or longer. Alumina xerogel prepared in a form of powder demonstrates luminescence in the blue range, which disappears totally after annealing at 800 ÂşC. Photoluminescence of porous anodic alumina which contains terbium ions in the xerogel of alumina or deposited from solutions of salts formed in the anodic alumina pores has been investigated. The perspectives of formation of planar microstructures using a porous anodic alumina supporting electromagnetic whispering gallery modes are discussed