Maximum entropy generation in open systems: the Fourth Law?

This paper develops an analytical and rigorous formulation of the maximum entropy generation principle. The result is suggested as the Fourth Law of Thermodynamics

Entropy generation and jet engine optimization

In 2009, it was shown that, with an original approach to hydrodynamic cavitation, a phenomenological model was realized in order to compute some of the physical parameters needed for the design of the most common technological applications (turbo-machinery, etc.) with an economical saving in planning because this analysis could allow engineers to reduce the experimental tests and the consequent costs in the design process. Here the same approach has been used to obtain range of some physical quantity for jet engine optimization

Gouy-Stodola Theorem as a variational principle for open systems

The recent researches in non equilibrium and far from equilibrium systems have been proved to be useful for their applications in different disciplines and many subjects. A general principle to approach all these phenomena with a unique method of analysis is required in science and engineering: a variational principle would have this fundamental role. Here, the Gouy-Stodola theorem is proposed to be this general variational principle, both proving that it satisfies the above requirements and relating it to a statistical results on entropy production.Comment: arXiv admin note: text overlap with arXiv:1101.131

Paths and stochastic order in open systems

The principle of maximum irreversible is proved to be a consequence of a stochastic order of the paths inside the phase space; indeed, the system evolves on the greatest path in the stochastic order. The result obtained is that, at the stability, the entropy generation is maximum and, this maximum value is consequence of the stochastic order of the paths in the phase space, while, conversely, the stochastic order of the paths in the phase space is a consequence of the maximum of the entropy generation at the stability

Entropy production and generation: clarity from nanosystems considerations

The interest in designing of nanosystems is continuously growing. In engineering many optimization approaches exist to design macroscopic machines. If these methods could be introduced in the nanosystems designing, a great improvement would be obtained in nanotechnologies. But, it is necessary to obtain a link between classical thermodynamics and nanosystems. The aim of this paper is to obtain a first step towards this link. Some considerations on the role of power, time and non equilibrium temperature are discussed and a link between non equilibrium temperature and macroscopic thermodynamic quantities is suggested. This last result opens to new questions

Bioengineering thermodynamics of biological cells

Background: Cells are open complex thermodynamic systems. They can be also regarded as complex engines that execute a series of chemical reactions. Energy transformations, thermo-electro-chemical processes and transports phenomena can occur across the cells membranes. Moreover, cells can also actively modify their behaviours in relation to changes in their environment. Methods: Different thermo-electro-biochemical behaviours occur between health and disease states. But, all the living systems waste heat, which is no more than the result of their internal irreversibility. This heat is dissipated into the environment. But, this wasted heat represent also a sort of information, which outflows from the cell toward its environment, completely accessible to any observer. Results: The analysis of irreversibility related to this wasted heat can represent a new approach to study the behaviour of the cells themselves and to control their behaviours. So, this approach allows us to consider the living systems as black boxes and analyze only the inflows and outflows and their changes in relation to the modification of the environment. Therefore, information on the systems can be obtained by analyzing the changes in the cell heat wasted in relation to external perturbations. Conclusions: The bioengineering thermodynamics bases are summarized and used to analyse possible controls of the calls behaviours based on the control of the ions fluxes across the cells membranes

Bioengineering Thermodynamics: An Engineering Science for Thermodynamics of Biosystems

Cells are open complex thermodynamic systems. Energy transformations, thermo-electro-chemical processes and transports occur across the cells membranes. Different thermo-electro-biochemical behaviours occur between health and disease states. Moreover, living systems waste heat, the result of the internal irreversibility. This heat is dissipated into the environment. But, this wasted heat represent a sort of information, which outflows from the cell toward its environment, completely accessible to any observer. Consequently, the analysis of irreversibility related to this wasted heat can represents a new approach to study the behaviour of the cells. So, this approach allows us to consider the living systems as black boxes and analyze only the inflows and outflows and their changes in relation to the modification of the environment. Therefore, information on the systems can be obtained by analyzing the changes in the cell heat wasted in relation to external perturbations. In this paper, a review of the recent results obtained by using this approach is proposed in order to highlight its thermodynamic fundamental: it could be the beginning of a new engineering science, the bioengineering thermodynamics. Some experimental evidences from literature are summarized and discussed. The approach proposed can allow us to explain them

The thermodynamic hamiltonian for open systems

The variational method is very important in mathematical and theoretical physics because it allows us to describe the natural systems by physical quantities independently from the frame of reference used. A global and statistical approach have been introduced starting from non-equilibrium thermodynamics, obtaining the principle of maximum entropy generation for the open systems. This principle is a consequence of the lagrangian approach to the open systems. Here it will be developed a general approach to obtain the thermodynamic hamiltonian for the dynamical study of the open systems. It follows that the irreversibility seems to be the fundamental phenomenon which drives the evolution of the states of the open systems

The Wasted Primary Resource Value: an Indicator for the Thermodynamics of Sustainability for Municipalities Policy

Exergy is a thermodynamic quantity which allows us to obtain information on the useful work obtainable in a process. The analyses of irreversibility are important in the design and development of the productive processes for the economic growth, but it plays a fundamental role in the thermodynamics analysis of socio-economic context of municipality. Consequently, the link between the wasted exergy and the energy cost for maintain the productive processes are linked based on the bioengineering thermodynamics. This link holds to the fundamental role of fluxes and to the exergy exchanged in the interaction between the system and its environment. A new indicator, the equivalent wasted primary resource value for the work-hour, is suggested to support the public managers for their economic decisions. Here, the Alessandria Municipality is analyzed in order to highlight the application of the theoretical results