Su una estensione del principio di Lagrange d'Alembert per un fluido viscoso relativistico

In this paper we show that it is possible to estabilish an autonomous formulation of the Lagrange-d’Alembert principle for a relativistic viscous fiuid in absence of mass forces. Rather it will be possible to obtain the indefinite equations starting from it

Relativistic phenomenological equations and transformation laws of relative coefficients

The aim of this paper is to derive the phenomenological equations in the context of special relativistic non-equilibrium thermodynamics with internal variables. In particular, after introducing some results developed in our previous paper, by means of classical non-equilibrium thermodynamic procedure and under suitable assumptions on the entropy density production, the phenomenological equations and transformation laws of phenomenological coefficients are derived. Finally, some symmetries of aforementioned coefficients are obtained

On evaluation of electric conductivity by means of a thermodynamical model for dieletric relaxation phenomena. An application to liver tissue

In this paper we study the electric conductivity of continuous media in the contest of the non-equilibrium thermodynamics with internal variables. Namely, we shall use some recent results that allow to infer conductivity as function of the frequency of perturbation, only by means of dielectric measurements. Although the results obtained can be applied to several materials, we have applied them to the study of electric conductivity on porcine liver tissue obtaining the spectrum frequency of conductivity (real and imaginary part)

Dynamics of segmental relaxations for cyanurate-containing semi-interpenetrating polymer networks

Two series of semi-interpenetrating polymer networks (semi-IPNs) of the same linear polyurethane (LPU) and two different heterocyclic polymer networks (HPN-1 and HPN-2) based on thermally cured dicyanic ether of Bisphenol-A, were characterized by differential scanning calorimetry (DSC), complex dynamic modulus E* = E' + iE" and mechanical loss tangent (tan $\delta$ = E"/E', where E' and E" are the storage and loss components of the loss modulus, respectively). The temerature dependence of $\alpha_a$ and $\gamma$ relaxations were studied as a function of HPNs content. By the experimental results no large-scale structural heterogeneities were detected in sample with HPN-1. It has been observed that the inclusion of LPU softens both the HPN-1 and HPN-2 rigid networks which, on the contrary, affects the LPU chain motion by restricting the cooperative long-range segmental dynamics. Single glass transitions are observed in semi-IPN-1 which indicate an affinity between LPU and HPN-1 and also a large scale structural homogeneity. Differently from semi-IPN-1, two glass transitions are observed in semi-IPN-2, where the absence of chemical intermolecular interactions is thought to give rise to a double phase amorphous network, each phase preserving the main morphological characteristics of the pure components. Keywords: Anelasticity; Internal friction; Anharmonicity Pacs index: 61.40 km or 62.40+

Thermodynamics Characterization of Lung Carcinoma, Entropic Study and Metabolic Correlations

In recent years, the use of dielectric spectroscopy as an investigation technique to determine the chemical–physical characteristics of biological materials has had a great increase. This study used the non-equilibrium thermodynamics with internal variables theory to test the potential pathological features of lung cancer. After a brief exploration of the dielectric polarization concept highlighting some aspects that were used, some thermodynamic functions were obtained as functions of the frequency, both for lung tumor cells and physiological ones. Variations in the intensity of values but not in the trend of the curves were observed and this was attributed to the perturbing field. The trend of this field explains the behavior of phenomena described by other functions, as related to the frequencies of the perturbing field. Compared to the physiological ones, the cancer cells appeared to be “more predisposed” to conserve their state as characterized by minor entropy production, probably because this helped cells to obtain the required adenosine triphosphate (ATP) from the minimum amount of nutrients

A New Non-Equilibrium Thermodynamic Fractional Visco-Inelastic Model to Predict Experimentally Inaccessible Processes and Investigate Pathophysiological Cellular Structures

After remarking on non-equilibrium thermodynamics with internal variables, this paper highlights the importance of these variables to the study of biological systems. Internal variables can provide a more detailed description of biological processes that occur inside cells, tissues and organs. In order to introduce a fractional model on a visco-inelastic medium based on Kluitenberg’s non-equilibrium thermodynamics, the origin of the complex dynamic modulus is shown by means of linear response theory. This research recalls our previous work to develop an ultrasound wave technique that allows us to investigate biological systems, and introduces the fractional visco-inelastic model and relative generalized relaxation time, to show that it is possible to obtain the Cole–Cole model in a particular case

A New Non-Equilibrium Thermodynamic Fractional Visco-Inelastic Model to Predict Experimentally Inaccessible Processes and Investigate Pathophysiological Cellular Structures

After remarking on non-equilibrium thermodynamics with internal variables, this paper highlights the importance of these variables to the study of biological systems. Internal variables can provide a more detailed description of biological processes that occur inside cells, tissues and organs. In order to introduce a fractional model on a visco-inelastic medium based on Kluitenberg’s non-equilibrium thermodynamics, the origin of the complex dynamic modulus is shown by means of linear response theory. This research recalls our previous work to develop an ultrasound wave technique that allows us to investigate biological systems, and introduces the fractional visco-inelastic model and relative generalized relaxation time, to show that it is possible to obtain the Cole–Cole model in a particular case

Expanding the Repertoire of Dielectric Fractional Models: A Comprehensive Development and Functional Applications to Predict Metabolic Alterations in Experimentally-Inaccessible Cells or Tissues

In this paper, we present the theoretical approach developed by us in the network of dielectric fractional theories. In particular, we mention the general aspects of the non-equilibrium thermodynamics, and after an introduction to the interaction between biological tissues and electrical fields, we highlight the role of phenomenological and state equations; therefore, we recall a general formulation on linear response theory. In Section 6, we introduce the classical fractional model. All of this is essential to show the role and the importance of fractional models in the context of thermodynamic dielectric investigations (of living or inert matter), giving a complete vision of the fractional approach. In Section 7 and Section 8, we introduce our new fractional model derived from non-equilibrium thermodynamic considerations