Arcangelo Labianca†, Lidia Palese‡ , Liliana Restuccia§
Abstract: In a previous paper, a linear theory for magnetic relaxation phenomena in reacting anisotropic fluid mixtures was developed, within the framework of the irreversible processes thermodynamics with internal variables. In that model, the total magnetization was split into two irreversible contributions, introducing one of them as an internal variable. In this paper, the same approach is applied to isotropic and perfect isotropic magnetizable reacting fluid mixtures. In the latter case, it is shown that in the phenomenological equations no cross effects arise between magnetic relaxation and other irreversible phenomena, since fluxes and thermodynamic forces of different tensorial character do not couple (Curie’s principle). For perfect isotropic mixtures, we also derive the equations of state and the magnetic relaxation equation, which, unlike in the anisotropic case, do not contain contributions from temperature, concentrations, and their time derivatives. Special cases are treated. The results have applications in nuclear resonance, biology, medicine, and other fields.
Keywords: continuum thermodynamics, classical irreversible thermo- dynamics, reacting fluid mixtures with magnetic relaxation, internal variables, isotropic media.
MSC: 53C21, 53C24, 53C25.
DOI 10.56082/annalsarscimath.2025.3.409
† arcangelo.labianca@uniba.it, Department of Mathematics, University of Bari, Via E. Orabona, 4, 70125 Bari, Italy
‡ lidiarosaria.palese@uniba.it, Department of Mathematics, University of Bari, Via E. Orabona, 4, 70125 Bari, Italy
§ lrestuccia@unime.it, Accademia Peloritana dei Pericolanti, University of Messina, Piazza S. Pugliatti, 1, 98122 Messina, Italy
PUBLISHED in Annals Academy of Romanian Scientists Series on Mathematics and Its Application, Volume 17 no 3, 2025
