8,693 research outputs found
Effects of inhalation of Freon 113 on laboratory animals
Four monkeys, 8 dogs, 40 mice, and 50 rats were exposed continuously to 2000 ppm Freon 113 in a Thomas Dome for 14 days. This exposure produced no mortalities nor adverse symptomology. There were no significant alterations in hematological values, clinical chemistries, electroencephalographic findings, body weights, or organ to body weight ratios. The effect of 2% Freon 113 on nicotinic transmission through the stellate ganglion of the spinal dog was also evaluated. The exposure induced a reduction in nicotinic transmission comparable to 2% halothane
Observation of mixed anisotropy in the critical susceptibility of an ultrathin magnetic film
Measurements of the magnetic susceptibility of Fe/W(110) films with thickness
in the range of 1.6 to 2.4 ML Fe, show that in addition to the large response
along the easy axis associated with the Curie transition, there is a much
smaller, paramagnetic hard axis response that is not consistent with the 2D
anisotropic Heisenberg model used to describe homogeneous in-plane ferromagnets
with uniaxial anisotropy. The shape, amplitude, and peak temperature of the
hard axis susceptibility, as well as its dependence upon layer completion close
to 2.0 ML, indicate that inhomogeneities in the films create a system of mixed
anisotropy. A likely candidate for inhomogeneities that are magnetically
relevant in the critical region are the closed lines of step edges associated
with the incomplete layers. According to the Harris criterion, the existence of
magnetically relevant inhomogeneities may alter the critical properties of the
films from those of a 2D Ising model. Experiments in the recent literature are
discussed in this context.Comment: 9 two-column pages, 6 figures. This replacement has a new title and
abstract, and one additional figur
Optimal control of predictive mean-field equations and applications to finance
We study a coupled system of controlled stochastic differential equations
(SDEs) driven by a Brownian motion and a compensated Poisson random measure,
consisting of a forward SDE in the unknown process and a
\emph{predictive mean-field} backward SDE (BSDE) in the unknowns . The driver of the BSDE at time may depend not just upon the
unknown processes , but also on the predicted future
value , defined by the conditional expectation . \\ We give a sufficient and a necessary
maximum principle for the optimal control of such systems, and then we apply
these results to the following two problems:\\ (i) Optimal portfolio in a
financial market with an \emph{insider influenced asset price process.} \\ (ii)
Optimal consumption rate from a cash flow modeled as a geometric It\^ o-L\'
evy SDE, with respect to \emph{predictive recursive utility}
Investigation of spray dispersion and particulate formation in diesel fuel flames
An experimental study of electrostatical atomized and dispersed diesel fuel jets was conducted at various back pressures to 40 atm. A new electrostatic injection technique was utilized to generate continuous, stable fuel sprays at charge densities of 1.5 to 2.0 C/m3 of fluid at one atm, and about 1.0 C/m3 at 40 atm. Flowrates were varied from 0.5 to 2.5 ml/s and electric potentials to -18 kV. Visual observations showed that significant enhanced dispersion of charged fuel jets occurred at high back pressures compared to aerodynamic breakup and dispersion. The average drop size was about the same as the spray triode orifice diameter, and was between the Kelly theory and the Rayleigh limit. The ignition tests, done only at one atm, indicated stable combustion of the electrostatically dispersed fuel jets
Systematics of heavy-ion fusion hindrance at extreme sub-barrier energies
The recent discovery of hindrance in heavy-ion induced fusion reactions at
extreme sub-barrier energies represents a challenge for theoretical models.
Previously, it has been shown that in medium-heavy systems, the onset of fusion
hindrance depends strongly on the "stiffness" of the nuclei in the entrance
channel. In this work, we explore its dependence on the total mass and the
-value of the fusing systems and find that the fusion hindrance depends in a
systematic way on the entrance channel properties over a wide range of systems.Comment: Submitted to Phys. Rev. Lett., 5 pages, 3 figure
Beam-Energy and System-Size Dependence of Dynamical Net Charge Fluctuations
We present measurements of net charge fluctuations in collisions at
19.6, 62.4, 130, and 200 GeV, collisions at
62.4, 200 GeV, and collisions at 200
GeV using the net charge dynamical fluctuations measure . The
dynamical fluctuations are non-zero at all energies and exhibit a rather modest
dependence on beam energy. We find that at a given energy and collision system,
net charge dynamical fluctuations violate scaling, but display
approximate scaling. We observe strong dependence of dynamical
fluctuations on the azimuthal angular range and pseudorapidity widths.Comment: 4 pages, 4 figures, presented at the 19th International Conference on
Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur,
India, February 4-10, 200
Bifurcation Phenomena in Two-Dimensional Piecewise Smooth Discontinuous Maps
In recent years the theory of border collision bifurcations has been
developed for piecewise smooth maps that are continuous across the border, and
has been successfully applied to explain nonsmooth bifurcation phenomena in
physical systems. However, many switching dynamical systems have been found to
yield two-dimensional piecewise smooth maps that are discontinuous across the
border. The theory for understanding the bifurcation phenomena in such systems
is not available yet. In this paper we present the first approach to the
problem of analysing and classifying the bifurcation phenomena in
two-dimensional discontinuous maps, based on a piecewise linear approximation
in the neighborhood of the border. We explain the bifurcations occurring in the
static VAR compensator used in electrical power systems, using the theory
developed in this paper. This theory may be applied similarly to other systems
that yield two-dimensional discontinuous maps
Simultaneous observation of high order multiple quantum coherences at ultralow magnetic fields
We present a method for the simultaneous observation of heteronuclear
multi-quantum coherences (up to the 3rd order), which give an additional degree
of freedom for ultralow magnetic field (ULF) MR experiments, where the chemical
shift is negligible. The nonequilibrium spin state is generated by Signal
Amplification By Reversible Exchange (SABRE) and detected at ULF with
SQUID-based NMR. We compare the results obtained by the heteronuclei Correlated
SpectroscopY (COSY) with a Flip Angle FOurier Series (FAFOS) method. COSY
allows a quantitative analysis of homo- and heteronuclei quantum coherences
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