Informational Statistical Thermodynamics and Thermal Laser Stereolithography

Abstract

We consider the nonequilibrium thermodynamic aspects of the techno-industrial process of thermal laser Stereolithography. The conditions necessary for a satisfactory process of rapid prototyping to follow are characterized and discussed. We show that the process is best described in terms of modern theories of nonequilibrium thermodynamics of dissipative systems. Nonconservative fluxes need to be introduced as basic variables, quite in the spirit of extended irreversible thermodynamics, to explain the experimental results. We also show that by varying the thermal properties of the material, the restricted domain of validity of the traditional classical irreversible thermodynamics is reached: to have diffusive motion predominating over long-rangepropagating undulatory motion is fundamental for the technique.

Considerations on undistorted-progressive X-waves and Davydov solitons, Fröhlich-Bose-Einstein condensation, and Cherenkov-like effect in biosystems

“…The NESOM, which provides microscopic foundations to phenomenological irreversible thermodynamics [19], also allows for the construction of a nonlinear generalized quantum transport theory -a far-reaching generalization of the Chapman-Enskog's and Mori's methods -which describes the evolution of the system at the macroscopic level in arbitrary nonequilibrium situations [20,[23][24][25], a formalism to be used in what follows. We notice that the method has been applied with particular success to the study of optical and transport properties in solids [26] and also to modelled biopolymers [27,28], of the kind we consider here, and to techno-industrial processes [29]. Consequently, we do not go over the details of the formalism, just adapting those earlier results for the present discussion, giving in each case the reference where they are reported.…”

Higher-order generalized hydrodynamics: Foundations within a nonequilibrium statistical ensemble formalism

“…[64]). This fact was a result, as shown in [64], that the addition of impurities modifies (decreases) Maxwell time for the flux (current) of energy (and then of nonequilibrium temperature) thus modifying the frontier that separates the damped wave and the diffusion regimes, characterized by the wave number k M = [c h θ I h ] −1 (c h the velocity of propagation of the flux-of the order of the thermal velocity-and the flux-Maxwell time θ I h ). Depending on the domain of relevant values of wave numbers k contributing to the movement, for k > k M the motion is basically a damped oscillatory one, while for k < k M there follows overdamped movement, i.e., a diffusive one (see Fig.…”

“…Depending on the domain of relevant values of wave numbers k contributing to the movement, for k > k M the motion is basically a damped oscillatory one, while for k < k M there follows overdamped movement, i.e., a diffusive one (see Fig. 2 in [64]). Thus, with the predominance of the diffusive motion the heat generated at the spot of the laser illumination there remains localized at sufficient times to get cooled in the impurified resin.…”

A nonequilibrium ensemble formalism: Criterion for truncation of description

“…͑29͒; this result is well known from textbook analyses of the telegraphist equation. 32 We call attention to the fact that the transition from damped wave motion to near diffusive motion, becomes evident in experiments related to the technoindustrial process of thermal-laser stereolithography 33 briefly described in next section.…”

“…The theoretical and experimental aspects are describe in detail in Ref. 33, to which we refer the reader, and here we only briefly summarize the results.…”