636 research outputs found
Implementação de serviços web com Axis2.
A utilização de serviços web tem se consolidado ao longo dos anos, como uma estratégia para a integração de sistemas desenvolvidos em plataformas e ambientes distintos. O Ainfo é o sistema da Embrapa para a gestão do acervo documental e digital da empresa, e inclui o registro das metas de produção técnico-científico. O SIDE é o Sistema de Apoio à Decisão Estratégica e, entre outras funcionalidades, utiliza os dados de produção científica do Ainfo para mensurar o desempenho das unidades da Empresa Brasileira de Pesquisa Agropecuária (Embrapa). Dessa forma, faz-se necessário realizar a integração desses sistemas, de modo a automatizar o envio de dados do Ainfo para o SIDE com rapidez, qualidade e confiabilidade. O objetivo do trabalho é apresentar o mecanismo de integração entre os dois sistemas, sob o aspecto de envio de dados de publicações, por meio de serviços web
Pion-pair formation and the pion dispersion relation in a hot pion gas
The possibility of pion--pair formation in a hot pion gas, based on the
bosonic gap equation, is pointed out and discussed in detail. The critical
temperature for condensation of pion pairs (Evans--Rashid transition) is
determined as a function of the pion density. As for fermions, this phase
transition is signaled by the appearance of a pole in the two--particle
propagator. In bose systems there exists a second, lower critical temperature,
associated with the appearance of the single--particle condensate. Between the
two critical temperatures the pion dispersion relation changes from the usual
quasiparticle dispersion to a Bogoliubov--like dispersion relation at low
momenta. This generalizes the non-relativistic result for an attractive bose
gas by Evans et al. Possible consequences for the inclusive pion spectra
measured in heavy--ion collisions at ultra--relativistic energies are
discussed.Comment: 16 pages revtex, 7 Postscript figure
REMOVED: Surface Modification of Mixed Matrix Membranes for the Reduction of Fouling
This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)
Radial flow has little effect on clusterization at intermediate energies in the framework of the Lattice Gas Model
The Lattice Gas Model was extended to incorporate the effect of radial flow.
Contrary to popular belief, radial flow has little effect on the clusterization
process in intermediate energy heavy-ion collisions except adding an ordered
motion to the particles in the fragmentation source. We compared the results
from the lattice gas model with and without radial flow to experimental data.
We found that charge yields from central collisions are not significantly
affected by inclusion of any reasonable radial flow.Comment: 8 pages, 2 figures, submitted to PRC; Minor update and resubmitted to
PR
Coulomb Effect: A Possible Probe for the Evolution of Hadronic Matter
Electromagnetic field produced in high-energy heavy-ion collisions contains
much useful information, because the field can be directly related to the
motion of the matter in the whole stage of the reaction. One can divide the
total electromagnetic field into three parts, i.e., the contributions from the
incident nuclei, non-participating nucleons and charged fluid, the latter
consisting of strongly interacting hadrons or quarks. Parametrizing the
space-time evolution of the charged fluid based on hydrodynamic model, we study
the development of the electromagnetic field which accompanies the high-energy
heavy-ion collisions. We found that the incident nuclei bring a rather strong
electromagnetic field to the interaction region of hadrons or quarks over a few
fm after the collision. On the other hand, the observed charged hadrons'
spectra are mostly affected (Coulomb effect) by the field of the charged fluid.
We compare the result of our model with experimental data and found that the
model reproduces them well. The pion yield ratio pi^-/pi+ at a RHIC energy,
Au+Au 100+100 GeV/nucleon, is also predicted.Comment: 23 pages, RevTex, 19 eps figures, revised versio
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Real-time feasibility of nonlinear model predictive control for semi-batch reactors subject to uncertainty and disturbances
This paper presents two nonlinear model predictive control based methods for solving closed-loop stochastic dynamic optimisation problems, ensuring both robustness and feasibility with respect to state output constraints. The first one is a new deterministic approach, using the wait-and-see strategy. The key idea is to specifically anticipate violation of output hard-constraints, which are strongly affected by instantaneous disturbances, by backing off of their bounds along the moving horizon. The second method is a stochastic approach to solve nonlinear chance-constrained dynamic optimisation problems under uncertainties. The key aspect is the explicit consideration of the stochastic properties of both exogenous and endogenous uncertainties in the problem formulation (here-and-now strategy). The approach considers a nonlinear relation between uncertain inputs and the constrained state outputs. The performance of the proposed methodologies is assessed via an application to a semi-batch reactor under safety constraints, involving strongly exothermic reactions
Coulomb corrections to the three-body correlation function in high-energy heavy ion reactions
Starting from an asymptotically correct three-body Coulomb wave-function, we
determine the effect of Coulomb final state interaction on the three-particle
Bose-Einstein correlation function of similarly charged particles. We
numerically estimate that the Riverside approximation is not precise enough to
determine the three-body Coulomb correction factor in the correlation function,
if the characteristic HBT radius parameter is 5 - 10 fm, which is the range of
interest in high-energy heavy ion physics.Comment: 14 pages, 4 figure
Production of phi mesons in subthreshold heavy-ion collisions
Within a BUU type transport model we study meson production in
subthreshold Ni+Ni and Ru+Ru reactions. For the first time we included in our
model the elementary reaction channels , and . In spite of a substantial increase of
the multiplicities by these channels our results stay significantly
below the preliminary experimental data.Comment: 4 pages, 2 figures, version to be published in the proceedings of the
SQM2001 Conference (Frankfurt, Germany, 25-29 Sep 2001
Enthalpy as internal energy in plug flow reactor models: A long-lasting assumption defeated and its effects on models predictions in dynamic regime
In this paper, a general dynamic model of a pseudo-homogeneous catalytic plug flow reactor (PFR) is developed, which does not apply the traditional assumption of negligible difference between enthalpy and internal energy inside its energy balance. Such a model is then compared to a second dynamic PFR model, whose energy conservation equation identifies internal energy with enthalpy. The aim is that of quantitatively investigating the real suitability of the identification of these two thermodynamic quantities (internal energy and enthalpy) in PFR modeling problems. The Claus process is selected as a meaningful case study for the aforementioned purposes
Size of Fireballs Created in High Energy Lead-Lead Collisions as Inferred from Coulomb Distortions of Pion Spectra
We compute the Coulomb effects produced by an expanding, highly charged
fireball on the momentum distribution of pions. We compare our results to data
on Au+Au at 11.6 A GeV from E866 at the BNL AGS and to data on Pb+Pb at 158 A
GeV from NA44 at the CERN SPS. We conclude that the distortion of the spectra
at low transverse momentum and mid-rapidity can be explained in both
experiments by the effect of the large amount of participating charge in the
central rapidity region. By adjusting the fireball expansion velocity to match
the average transverse momentum of protons, we find a best fit when the
fireball radius is about 10 fm, as determined by the moment when the pions
undergo their last scattering. This value is common to both the AGS and CERN
experiments.Comment: Enlarged discussion, new references added, includes new analysis of
pi-/pi+ at AGS energies. 12 pages 5 figures, uses LaTex and epsfi
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