183 research outputs found
Νέο υστερητικό προσομοίωμα για την μονοδιάστατη ανάλυση της σεισμικής απόκρισης πολύστρωτου εδαφικού σχηματισμού
Systematic grid-wise radon concentration measurements and first radon map in Cyprus
A systematic study of the indoor airborne radon concentration in the central
part of the Nicosia district was conducted, using high-sensitivity active radon
portable detectors of the type "RADIM3A". From a total of 108 measurements in
54 grids of 1 km^2 area each, the overall mean value is 20.6 \pm 13.2 Bq m^-3
(A.M.\pm S.D.). That is almost twice less than the corresponding average
worldwide value. The radon concentration levels in drinking water were also
measured in 24 sites of the residential district, using the high-sensitivity
radon detector of the type "RADIM3W". The mean value obtained from these
measurements is 243.8 \pm 224.8 mBq L^-1, which is relatively low compared to
the corresponding internationally accepted level. The associated annual
effective dose rates to each measurement were also calculated and compared to
the corresponding worldwide values. From the geographical coordinates of the
measuring sites and the corresponding radon concentration values, the digital
radon map of the central part of the Nicosia district was constructed for the
first time, by means of the ArcMap software package.Comment: 21 pages including 2 tables and 8 figure
Gamow peak in thermonuclear reactions at high temperatures
The Gamow peak represents one of the most important concepts in the study of thermonuclear reactions in stars. It is widely used in order to determine, at a given plasma temperature, the effective stellar energy region in which most charged-particle induced nuclear reactions occur. It is of importance in the design of nuclear astrophysics measurements, including those involving radioactive ion beams, and for the determination of stellar reaction rates. We demonstrate that the Gamow peak concept breaks down under certain conditions if a nuclear reaction proceeds through narrow resonances at elevated temperatures. It is shown that an effective stellar energy window does indeed exist in which most thermonuclear reactions take place at a given temperature, but that this energy window can differ significantly from the commonly used Gamow peak. We expect that these findings are especially important for thermonuclear reactions in the advanced burning stages of massive stars and in explosive stellar environments
Charged-Particle Thermonuclear Reaction Rates: III. Nuclear Physics Input
The nuclear physics input used to compute the Monte Carlo reaction rates and
probability density functions that are tabulated in the second paper of this
series (Paper II) is presented. Specifically, we publish the input files to the
Monte Carlo reaction rate code RatesMC, which is based on the formalism
presented in the first paper of this series (Paper I). This data base contains
overwhelmingly experimental nuclear physics information. The survey of
literature for this review was concluded in November 2009.Comment: 132 page
Partial Wave Analysis of the Reaction to Search for the "" Bound State
Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have
analyzed HADES data of the reaction . This
reaction might contain information about the kaonic cluster "" via its
decay into . Due to interference effects in our coherent description
of the data, a hypothetical (or, specifically "")
cluster signal must not necessarily show up as a pronounced feature (e.g. a
peak) in an invariant mass spectra like . Our PWA analysis includes a
variety of resonant and non-resonant intermediate states and delivers a good
description of our data (various angular distributions and two-hadron invariant
mass spectra) without a contribution of a cluster. At a
confidence level of CL=95\% such a cluster can not contribute more than
2-12\% to the total cross section with a final state, which
translates into a production cross-section between 0.7 and 4.2 ,
respectively. The range of the upper limit depends on the assumed cluster mass,
width and production process.Comment: 7 Pages, 5 Figure
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