Hesham Mansour

Self-Consistent Green Function Calculations for Isospin Asymmetric Nuclear Matter

(Received September 1, 2009; Revised February 2, 2010)The one-body potentials for protons and neutrons are obtained from the self-consistentGreen-function calculations of asymmetric nuclear matter, in particular their dependence onthe degree of proton/neutron asymmetry. Results of the binding energy per nucleon as afunction of the density and asymmetry parameter are presented for the self-consistent Greenfunction approach using the CD-Bonn potential. For the sake of comparison, the same cal-culations are performed using the Brueckner-Hartree-Fock approximation. The contributionof the hole-hole terms leads to a repulsive contribution to the energy per nucleon whichincreases with the nuclear density. The incompressibility for asymmetric nuclear matter hasbeen also investigated in the framework of the self-consistent Green-function approach usingthe CD-Bonn potential. The behavior of the incompressibility is studied for different valuesof the nuclear density and the neutron excess parameter. The nuclear symmetry potentialat fixed nuclear density is also calculated and its value decreases with increasing the nu-cleon energy. In particular, the nuclear symmetry potential at saturation density changesfrom positive to negative values at nucleon kinetic energy of about 200 MeV. For the sakeof comparison, the same calculations are performed using the Brueckner-Hartree-Fock ap-proximation. The proton/neutron effective mass splitting in neutron-rich matter has beenstudied. The predicted isospin splitting of the proton/neutron effective mass splitting inneutron-rich matter is such that

Single-Particle Spectrum of Pure Neutron Matter

We have calculated the self-consistent auxiliary potential effects on the binding energy of neutron matter using the Brueckner–Hartree–Fock approach by adopting the Argonne V18 and CD-Bonn potentials. The binding energy with the four different choices for the self-consistent auxiliary potential is discussed. Also, the binding energy of neutron matter has been computed within the framework of the self-consistent Green’s function approach. We also compare the binding energies obtained in this study with those obtained by various microscopic approaches. It is found that the use of the continuous choice tends to give binding energies about 2–4 MeV larger than the gap choice at kF = 1.8 fm−1. In the case of symmetric nuclear matter this difference is larger.

The properties of nuclear matter at zero and finite temperatures

The properties of nuclear matter are studied in the frame of the Brueckner theory. The Brueckner-Hartree-Fock approximation plus two-body density-dependent Skyrme potential which is equivalent to three-body interaction are used. Various modern nucleon-nucleon potentials are used in the framework of the Brueckner-Hartree-Fock approximation, e.g.: CD-Bonn potential, Nijm1 potential, and Reid 93 potential. These modern nucleon-nucleon potentials fit the deuteron properties and are phase shifts equivalent. The equation of state at T = 0, pressure at T = 0, 8, and 12 MeV, free energy at T = 8 and 12 MeV, nuclear matter incompressibility, and the symmetry energy calculation are presented. The hot properties of nuclear matter are calculated using T2-approximation method at low temperatures. Good agreement is obtained in comparison with previous theoretical estimates and experimental data, especially at low densities.

Nuclear matter equation of state and three-body forces

The energy per particle, symmetry energy, pressure, and free energy are calculated for symmetric nuclear matter using BHF approach with modern nucleon-nucleon CD-Bonn, Nijm1, Argonne v18, and Reid 93 potentials. To obtain saturation in nuclear matter we add three-body interaction terms which are equivalent to a density-dependent two-nucleon interaction a la Skyrme force. Good agreement is obtained in comparison with previous theoretical estimates and experimental data.The energy per particle, symmetry energy, pressure, Free energy are calculated for asymmetric nuclear matter using BHF approach and modern nucleon-nucleon CD-Bonn, Nijm1, Argonnev18 and Reid93 potentials. To obtain saturation in nuclear matter we add three-body interaction terms which are equivalent a la Skyrme to a density-dependent two-nucleon interaction. Good agreement is obtained in comparison with previous theoretical estimates and experimental data.

Equation of State and Symmetry Energy at High Densities for Zero and Finite Temperatures

The equation of state of isospin asymmetric nuclear matter within the framework of the Brueckner theory is used to calculate the energy per particle for nuclear and neutron matter. Pressure and symmetry energy are also presented. Here we extended our work to include Skyrme-like zero-range density-dependent two-body forces, which could mimic three-body forces. A three-body forces are shown to be necessary for reproducing the empirical saturation properties of symmetric nuclear matter. We also studied the effect of extending the calculation to finite temperatures.

Asymmetric nuclear matter and Skyrme potential

The binding energy, symmetry energy, pressure, incompressibility, and the velocity of sound are calculated for asymmetric nuclear matter using Skyrme interaction SkO’. The behavior of these physical quantities is studied for different values of the asymmetry parameter ατ, the density ρ, and the temperature T. Good agreement is obtained in comparison with previous theoretical estimates and experimental data.

Incompressibility and single-particle potential for asymmetric nuclear matter with Skyrme potential

The incompressibility and the single-particle potential of asymmetric nuclear matter have been investigated in the framework of the Skyrme interaction. These parameters have been studied as functions of the nuclear density, the neutron excess parameter, and the temperature. The ratio of the isothermal incompressibility of hot nuclear matter to the incompressibility of cold nuclear matter for different values of neutron excess as a function of temperature is calculated. It is observed that this ratio decreases with temperature increasing apart from pure neutron matter when the growth of temperature leads to the growth of incompressibility. The symmetry incompressibility has been calculated as a function of density for different values of temperature.

Computer guided sinus floor elevation through lateral window approach with simultaneous implant placement

BACKGROUND The introduction of CAD/CAM technology in implant dentistry has marked a new era, allowing various procedures to be carried out with a level of great precision and accuracy. PURPOSE The aim of the present study is to compare the efficacy of a CAD/CAM generated surgical cutting guide in the reduction of incidence of membrane perforation during maxillary sinus floor elevation in relation to the standard lateral window approach technique. MATERIALS AND METHODS Twenty cases of maxillary sinus elevation were randomly divided into 2 groups. The first group received computer guided sinus floor elevation through lateral window approach and simultaneous implant placement while the second group received standard sinus elevation procedure through lateral window approach with simultaneous implant placement. RESULTS In the computer guided group, 3 out of 10 cases presented with sinus septa, only 1 case suffered from membrane perforation during the elevation process. In the non-guided group, 3 cases suffered from membrane perforation, 2 of which were complicated by sinus septa. CONCLUSION Within the limits of this study, computer guided sinus floor elevation showed promising results in accurately modifying the lateral window osteotomy and presents as a safe alternative to the standard technique.

Study of Asymmetric Nuclear Matter Using Skyrme Potential

The binding energy, symmetry energy, pressure, velocity of sound and the incompressibility are calculated for asymmetric nuclear matter using Skyrme interaction. The behavior of these physical quantities is studied for different values of the asymmetry parameter ατ, the density ρ and the temperature T.