Dan Grecu

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The argumentation services platform with integrated components (Aspic) project aims to provide advanced argumentation-based computational capabilities. Argumentation is a potentially important paradigm for developing commercial and public services that are flexible and easily understood by human users.
In this paper, we present a three-dimensional mathematical model for a normal hip joint. The three-dimensional finite element model has been constructed based on Computer Tomograph scans of the bones. The obtained 3D model is studied using the finite element method, taking into consideration the real structure of the bone and the mechanical characteristics(More)
In the real life, the leg and its skeleton are exposed at the most diverse stresses. It is known that the human bone is one of the most important natural composite materials. The paper presents a method of study and the steps to obtain the virtual bones of the human body, method applied to tibia bone. For that purpose was used a CAD parametric software(More)
The paper presents a method of study and the steps to obtain the virtual tibial component of the human knee joint prosthesis. For that purpose CAD parametric software was used which allows the construction of a high definition model. The obtained 3D model was studied using the finite element method and the stress and displacements distribution was obtained(More)
The discrete self-trapping equation (DST) represents an useful model for several properties of one-dimensional nonlinear molecular crystals. The modulational instability of DST equation is discussed from a statistical point of view, considering the oscillator amplitude as a random variable. A kinetic equation for the two-point correlation function is(More)
UNLABELLED The avascular necrosis of the femoral head is an illness induced by the cutoff of blood flow to the femoral head and it affects mostly young adults between the ages of 30 and 50 years, raising therapeutic and diagnostic issues. Many risk factors are incriminated in the development of avascular necrosis of the femoral head like: trauma, chronic(More)
The modulational instability (MI) of some discrete nonlinear evolution equations, representing approximations of Davydov's model of α-helix in protein, is studied. In a multiple scales analysis the dominant amplitude usually satisfies the nonlinear Schrödinger equation (NLS), or the Zakharov–Benney equations (ZB), if a long wave-short wave resonance takes(More)
A system of coupled NLS equations (integrable and non-integrable) is discussed using a Madelung fluid description. The problem is equivalent with a two-component fluid of densities ρ 1 and ρ 2 and velocities υ 1 and υ 2 , which satisfy equations of continuity and equations of motion. Provided that the nonlinear coupling coefficients are identical, several(More)
For our study were available fragments of bony tissue from 24 patients (15 females and 9 males) aged between 55-82 which needed hip arthroplasty after they had undergone femural neck fractures. Biologic pieces have been fixed, then decalcified and processed by wax embedding. We noted that the spongious osseous tissue appeared as rarefied after the(More)
One-dimensional nonlinear lattices with harmonic long range interaction potentials (LRIP) of inverse power type are studied. For the nearest neighbour nonlinear interaction we shall consider the anharmonic potential of the Fermi-Pasta-Ulam problem and the φ 3 +φ 4 as well. The continuum limit is obtained following the method used by Ishimori [1], and(More)