215 research outputs found
The complement: a solution to liquid drop finite size effects in phase transitions
The effects of the finite size of a liquid drop undergoing a phase transition
are described in terms of the complement, the largest (but still mesoscopic)
drop representing the liquid in equilibrium with the vapor. Vapor cluster
concentrations, pressure and density from fixed mean density lattice gas
(Ising) model calculations are explained in terms of the complement. Accounting
for this finite size effect is key to determining the infinite nuclear matter
phase diagram from experimental data.Comment: Four two column pages, four figures, two tables; accepted for
publication in PR
Role of isospin dependent mean field in pion production in heavy ion reactions
The importance of a isospin dependent nuclear mean field (IDMF) in regard to
the pion production mechanism is studied for the reaction at 1
GeV/nucleon using the Quantum Molecular Dynamics (QMD) model. In particular,
the effect of the IDMF on pion spectra and the charged pion ratio are analyzed.
It is found that the inclusion of a IDMF considerably suppresses the low
pions, thus, leading to a better agreement with the data on pion spectra.
Moreover, the rapidity distribution of the charged pion ratio appears to be
sensitive to the isospin dependence of the nuclear mean field.Comment: 16 pages, using RevTex, 6 PS-Figure
HAVOSS: A Maturity Model for Handling Vulnerabilities in Third Party OSS Components
Security has been recognized as a leading barrier for IoT adoption. The growing number of connected devices and reported software vulnerabilities increases the importance firmware updates. Maturity models for software security do include parts of this, but are lacking in several aspects. This paper presents and evaluates a maturity model (HAVOSS) for handling vulnerabilities in third party OSS and COTS components. The maturity model was designed by first reviewing industry interviews, current best practice guidelines and other maturity models. After that, the practices were refined through industry interviews, resulting in six capability areas covering in total 21 practices. These were then evaluated based on their importance according to industry experts. It is shown that the practices are seen as highly important, indicating that the model can be seen as a valuable tool when assessing strengths and weaknesses in an organization's ability to handle firmware updates
Modulation Theory and Systems
Contains research objectives and reports on one research project
Correlation functions and emission time sequence of light charged particles from projectile-like fragment source in E/A = 44 and 77 MeV 40Ar + 27Al collisions
Two-particle correlation functions, involving protons, deuterons, tritons,
and alpha-particles, have been measured at very forward angles (0.7 deg <
theta_lab < 7 deg), in order to study projectile-like fragment (PLF) emission
in E/A = 44 and 77 MeV 40Ar + 27Al collisions. Peaks, originating from
resonance decays, are larger at E/A = 44 than at 77 MeV. This reflects the
larger relative importance of independently emitted light particles, as
compared to two-particle decay from unstable fragments, at the higher beam
energy. The time sequence of the light charged particles, emitted from the PLF,
has been deduced from particle-velocity-gated correlation functions (discarding
the contribution from resonance decays). Alpha-particles are found to have an
average emission time shorter than protons but longer than tritons and
deuterons.Comment: 18 pages, 5 figures, submitted to Nuclear Physics
Anomalous radial expansion in central heavy-ion reactions
The expansion velocity profile in central heavy-ion reactions in the Fermi
energy domain is examined. The radial expansion is non-hubblean and in the
surface region it scales proportional to a higher exponent () of
the radius. The anomalous expansion velocity profile is accompanied by a power
law nucleon density profile in the surface region. Both these features of
central heavy-ion reactions disappear at higher energies, and the system
follows a uniform Hubble expansion ()
Quantum-Statistical Correlations and Single Particle Distributions for Slowly Expanding Systems with Temperature Profile
Competition among particle evaporation, temperature gradient and flow is
investigated in a phenomenological manner, based on a simultaneous analysis of
quantum statistical correlations and momentum distributions for a
non-relativistic, spherically symmetric, three-dimensionally expanding, finite
source. The parameters of the model emission function are constrained by fits
to neutron and proton momentum distributions and correlation functions in
intermediate energy heavy-ion collisions. The temperature gradient is related
to the momentum dependence of the radius parameters of the two-particle
correlation function, as well as to the momentum-dependent temperature
parameter of the single particle spectrum, while a long duration of particle
evaporation is found to be responsible for the low relative momentum behavior
of the two-particle correlations.Comment: 20 pages + 5 ps figures, ReVTeX, uses psfig.sty, the description is
extended to include final state interactions, phenomenological evaporation
and to fit intermediate energy heavy ion proton and neutron spectrum and
correlation dat
Delta excitation in K^+-nucleus collisions
We present calculations for \Delta excitation in the (K^+,K^+) reaction in
nuclei. The background from quasielastic K^+ scattering in the \Delta region is
also evaluated and shown to be quite small in some kinematical regions, so as
to allow for a clean identification of the \Delta excitation strength. Nuclear
effects tied to the \Delta renormalization in the nucleus are considered and
the reaction is shown to provide new elements to enrich our knowledge of the
\Delta properties in a nuclear medium.Comment: 11 pages, 6 figures, LaTe
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