Absorption and percolation in the production of J/psi in heavy ion collisions

We present a simple model with string absorption and percolation to describe the J/psi suppression in heavy ion collisions. The NA50 data are fairly well explained by the model.Comment: 6 pages, 3 postscript figures include

Percolation approach to phase transitions in high energy nuclear collisions

We study continuum percolation in nuclear collisions for the realistic case in which the nuclear matter distribution is not uniform over the collision volume, and show that the percolation threshold is increased compared to the standard, uniform situation. In terms of quark-gluon plasma formation this means that the phase transition threshold is pushed to higher energies.Comment: 7 pages, 4 figures (PS), LaTeX2e using fontenc, amsmath, epsfi

Applicability of a Representation for the Martin's Real-Part Formula in Model-Independent Analyses

Using a novel representation for the Martin's real-part formula without the full scaling property, an almost model-independent description of the proton-proton differential cross section data at high energies (19.4 GeV - 62.5 GeV) is obtained. In the impact parameter and eikonal frameworks, the extracted inelastic overlap function presents a peripheral effect (tail) above 2 fm and the extracted opacity function is characterized by a zero (change of sign) in the momentum transfer space, confirming results from previous model-independent analyses. Analytical parametrization for these empirical results are introduced and discussed. The importance of investigations on the inverse problems in high-energy elastic hadron scattering is stressed and the relevance of the proposed representation is commented. A short critical review on the use of Martin's formula is also presented.Comment: Two comments and one reference added at the end of Subsec. 3.3; 23 pages, 9 figures; to be published in Int. J. Mod. Phys.

The current knowledge on Anastrepha Schiner (Dip., Tephritidae) in the State of Amapá, Brazil.

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Combination of topology and shape optimization with finite element modeling in the case of an aerospace component produced by laser based additive manufacturing

The present work applies a design for additive manufacturing-driven design methodology to an aeronautical component to be fabricated through an additive manufacturing (AM) process. This involves simulation of the process using Abaqus Finite Element software as well as the development of a design methodology concerning topology and shape optimization utilizing SIMULIA Tosca. A benchmarking AM simulation is performed first to provide validation and general guidelines needed to properly implement a low-resolution AM simulation in Abaqus. The structural optimization is started by volume minimization topology optimization. Solid isotropic material with penalization fails to achieve convergence with frequency response constraints, while mass interpolation material penalization converges to a well-connected design. The design interpretation with polyNURBs results in a single component with a weight reduction of 2.29% compared to current two component assemblies. Further implementation of shape optimization to address stress design requirements allows achieving stress homogeneity and a lower weight, resulting in a 5.12% weight reduction. The AM simulation process is applied to a scaled version of the final design to both assess the printability of the part itself as well as implementation of key tools to define the AM simulation. Maximum distortion of the part appears at expected regions with an overhanging material

Amazon network for research on fruit flies.

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Particle production azimuthal asymmetries in a clustering of color sources model

The collective interactions of many partons in the first stage of the collisions is the usual accepted explanation of the sizable elliptical flow. The clustering of color sources provides a framework of partonic interactions. In this scheme, we show a reasonable agreement with RHIC data for pT<1.5 GeV/c in both the dependence of v2 transverse momentum and in the shape of the nuclear modified factor on the azimuthal angle for different centralities. We show the predictions at LHC energies for Pb-Pb. In the case of proton-proton collisions a sizable v2 is obtained at this energy.Comment: To appear in Journal of Physics

Factorial Moments in a Generalized Lattice Gas Model

We construct a simple multicomponent lattice gas model in one dimension in which each site can either be empty or occupied by at most one particle of any one of $D$ species. Particles interact with a nearest neighbor interaction which depends on the species involved. This model is capable of reproducing the relations between factorial moments observed in high--energy scattering experiments for moderate values of $D$. The factorial moments of the negative binomial distribution can be obtained exactly in the limit as $D$ becomes large, and two suitable prescriptions involving randomly drawn nearest neighbor interactions are given. These results indicate the need for considerable care in any attempt to extract information regarding possible critical phenomena from empirical factorial moments.Comment: 15 pages + 1 figure (appended as postscript file), REVTEX 3.0, NORDITA preprint 93/4