Vincenzo Tibullo

Fermi-Dirac distributions for quark partons

AbstractWe propose to use Fermi-Dirac distributions for quark and antiquark partons. It allows a fair description of thex-dependence of the very recent NMC data on the proton and neutron structure functionsF2p(x) andF2n(x) atQ2=4 GeV2, as well as the CCFR antiquark distribution

On the wave propagation in the time differential dual-phase-lag thermoelastic model

x\bar q(x)

On the Uniqueness in Dynamical Thermoelasticity Backward in Time for Porous Media

. We show that one can also use a corresponding Bose-Einstein expression to describe consistently the gluon distribution. The Pauli exclusion principle, which has been identified to explain the flavor asymmetry of the light-quark sea of the proton, is advocated to guide us for making a simple construction of the polarized parton distributions. We predict the spin dependent structure functionsg1p(x) andg1n(x) in good agreement with EMC and SLAC data. The quark distributions involve some parameters whose values support well the hypothesis that the violation of the quark parton model sum rules is a consequence of the Pauli principle.

On the Heat-Flux Dependent Thermoelasticity for Micropolar Porous Media

ABSTRACT This paper concerns the linear theory of micropolar thermoelasticity without energy dissipation. We construct the fundamental solution of the system of differential equations in the case of steady oscillations in terms of elementary functions.

ON THE SPATIAL BEHAVIOR IN THE DYNAMIC THEORY OF MIXTURES OF THERMOELASTIC SOLIDS

We study the propagation of plane time harmonic waves in the infinite space filled by a time differential dual-phase-lag thermoelastic material. There are six possible basic waves travelling with distinct speeds, out of which, two are shear waves, and the remaining four are dilatational waves. The shear waves are found to be uncoupled, undamped in time and travels independently with the speed that is unaffected by the thermal effects. All the other possible four dilatational waves are found to be coupled, damped in time and dispersive due to the presence of thermal properties of the material. In fact, there is a damped in time longitudinal quasi-elastic wave whose amplitude decreases exponentially to zero when the time is going to infinity. There is also a quasi-thermal mode, like the classical purely thermal disturbance, which is a standing wave decaying exponentially to zero when the time goes to infinity. Furthermore, there are two possible longitudinal quasi-thermal waves that are damped in time with different decreasing rates or there is one plane harmonic in time longitudinal thermal wave, depending on the values of the time delays. The surface wave problem is studied for a half space filled by a dual-phase-lag thermoelastic material. The surface of the half space is free of traction and it is free to exchange heat with the ambient medium. The dispersion relation is written in an explicit way and the secular equation is established. Numerical computations are performed for a specific model, and the results obtained are depicted graphically.

Stability and Thermodynamic Restrictions for a Dual-Phase-Lag Thermal Model

In this paper the uniqueness of solutions for the backward in time problem of the linear theory of thermo-microstretch elastic materials is shown and the impossibility of the localization in time of the solution of the corresponding forward in time problem is proved. Moreover, the temporal behavior backward in time of thermoelastodynamics processes is studied by establishing the relations describing the asymptotic behavior of the Cesàro means of the different parts of the total energy.

Fermi-Dirac statistics plus liquid description of quark partons

The aim of this article is to study some uniqueness criteria for the solutions of boundary-final value problems associated with the linear theory of thermoelastic materials with voids. More precisely, the present study is devoted to the investigation of a backward in time problem associated with porous thermoelastic materials.

A thermoelastic diffusion theory with microtemperatures and microconcentrations

In the present paper, in the context of the linear theory of heat-flux dependent thermoelasticity for micropolar porous media, we derive a uniqueness theorem with no positive definiteness assumption on the elastic constitutive coefficients. Moreover, we prove, under non homogeneous initial conditions, a reciprocal relation and a variational principle. These generalize previous results about inhomogeneous and anisotropic micropolar thermoelastic materials.