38 research outputs found
Los beneficios para la cadena de suministro de manejar un inventario de manera optimizada
A lo largo de la presente tesis se desarrolló un marco teórico estadístico y operativo de cómo se manejan distintas estrategias de cadena de suministro e inventario para distintas industrias. Particularmente se hizo foco en la infraestructura y la cadena de suministro de Coca Cola FEMSA S.A. de manera tal de entender los productos que componen su portafolio, las capacidades de producción, la logística primaria y sus bodegas de almacenamiento
Determination of total I and 129I concentrations in freshwater of Argentina
Total iodine and129-iodine in rivers and lakes of Argentina were measured by means of inductively coupled plasma mass spectrometry and accelerator mass spectrometry respectively. The obtained isotopic ratios, higher than the natural level, are explained
Dynamical effects in heavy-ion interactions at bombarding energies near the Coulomb barrier: A study for the 16O + 120Sn system
Abstract We investigate the magnitude of the effective interactions for elastic and inelastic processes at bombarding energies in the vicinity of the nominal Coulomb barrier. The relevance of higher-order inelastic and transfer processes in defining the strength of the effective couplings is explored in a reaction with a superfluid target, 16 O on 120 Sn, at center-of-mass energies of 46, 50 and 54 MeV. Significant dynamical effects are found and these appear to be more pronounced in the off-diagonal matrix elements than in the diagonal ones. Theoretical arguments related to the data are presented
One- and two-proton transfer reactions with vibrational Nuclei
We extend a semiclassical model of transfer reactions to the case in which
one of the collision partners is a vibrational nucleus. The model is applied to
one- and two-proton stripping reactions in the 37Cl + 98Mo system, for which a
rapid transition from normal to anomalous slope in the two proton transfer
reaction at energies around the Coulomb barrier is experimentally observed.
This behavior is satisfactorily reproduced by the present extension of the
model.Comment: LaTeX, 10 pages, 1 figure (PostScript
Barrier Distributions as a Tool to Investigate Fusion and Fission
The recent availability of precisely measured fusion cross-sections has
enabled the extraction of a representation of the distribution of barriers
encountered during fusion. These representations, obtained from a variety of
reactions, provide a direct observation of how the structure of the fusing
nuclei changes the inter-nuclear potential landscape, thus affecting the fusion
probability. Recent experiments showing the effects of static quadrupole and
hexadecapole deformation, single-- and double-phonon states, transfer of
nucleons between two nuclei, and high lying excited states are reviewed. The
application of these concepts to the explanation of the anomalous
fission-fragment anisotropies observed following reactions with actinides is
discussed.Comment: 12 pages, To be published in the Proceedings of the NN 97 Conference,
Gatlinburg, Tennessee, June 1997 (Nucl. Phys. A
Long range effects on the optical model of 6He around the Coulomb barrier
We present an optical model (OM) analysis of the elastic scattering data of
the reactions 6He+27Al and 6He+208Pb at incident energies around the Coulomb
barrier. The bare part of the optical potential is constructed microscopically
by means of a double folding procedure, using the Sao Paulo prescription
without any renormalization. This bare interaction is supplemented with a
Coulomb dipole polarization (CDP) potential, which takes into account the
effect of the dipole Coulomb interaction. For this CDP potential, we use an
analytical formula derived from the semiclassical theory of Coulomb excitation.
The rest of the optical potential is parametrized in terms of Woods-Saxon
shapes. In the 6He+208Pb case, the analysis confirms the presence of long range
components, in agreement with previous works. Four-body Continuum-Discretized
Coupled-Channels calculations have been performed in order to better understand
the features of the optical potentials found in the OM analysis. This study
searches to elucidate some aspects of the optical potential of weakly bound
systems, such as the dispersion relation and the long range (attractive and
absorptive) mechanisms.Comment: Accepted in Nucl. Phys. A; 26 pages, 8 figures, 6 tables
No evidence of break-up effects on the fusion of 9Be with medium-light nuclei
AbstractFusion cross sections were measured for the 9Be+27Al and 19F+9Be, 12C systems, at energies above the Coulomb barrier, in order to investigate the possible effect of fusion hindrance due to the break-up of the weakly bound nuclei. Comparisons with one-dimensional barrier penetration models and with other similar systems, where no break-up is expected to occur, show no evidence of fusion hindrance
Bootstrap method for constructing covariance matrices of optical-model parameters in the study of the threshold anomaly
The parameters of optical-model potentials are usually obtained by adjusting theoretical calculations to the corresponding experimental elastic-scattering data. It has been observed that the use of conventional covariance matrices for the evaluation of the uncertainties of the parameters obtained in this way, leads in general to unrealistically small values. This underestimate may be caused by either, an incorrect use of the statistical recipes, or by the lack of a systematic study of the robustness of the uncertainty values against the inclusion or exclusion of experimental data points within a given data set. In the present contribution we explore both factors. Regarding the first aspect we use a re-normalization for χ2, similar to the one proposed by R.T. Birge. In the second case we use the Bootstrap method to create synthetic sets based on all the available experimental data in order to derive an effective covariance matrix. These procedures were applied to the re-analysis of elastic-scattering data for several heavy-ion systems at energies close to the Coulomb barrie
Determination of total I and 129
Total iodine and129-iodine in rivers and lakes of Argentina were measured by means of inductively coupled plasma mass spectrometry and accelerator mass spectrometry respectively. The obtained isotopic ratios, higher than the natural level, are explained as the delayed signal from nuclear weapon atmospheric tests. Besides, deposition fluences in catchment areas of the lakes are analyzed. Their latitudinal dependence, similar to the dependence of annual precipitation rates, favours wet deposition as the main 129I fallout mechanism for this region