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Cell membranes are the reason of the cell energy transfer. In cells energy transfer, thermo-electro-chemical processes and transports phenomena occur through their membranes. Cells can actively modify their behaviours in relation to any change of their environment. They waste heat into their environment. The analysis of irreversibility related to this wasted heat, to the ions transport and the related cell-environment pH changes represents a new useful approach to the study of the cells behaviour. This analysis allows also the explanation of the effects of electromagnetic fields on the cell behaviour, and to suggest how low intensity electromagnetic fields could represent a useful support to the present anticancer therapies.

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 analysed in order to highlight the application of the theoretical results.

The aim of this work was to analyse the pressure inside the eyes anterior chamber, namedintraocular pressure (IOP), in relation to the biomechanical properties of corneas. The approach used was based on the constructal law, recently introduced in vision analysis. Results were expressed as the relation between the temperature of the ocular anterior chamber and the biomechanical properties of the cornea. The IOP, the elastic properties of the cornea and the related refractive properties of the eye were demonstrated to be dependent on the temperature of the ocular anterior chamber. These results could lead to new perspectives for experimental analysis of the IOP in relation to the properties of the cornea.

The thermodynamic analysis of open systems is fundamental in engineering. For the open systems at their steady state, two apparently opposed principles for the rate of entropy production have been used: the minimum entropy production rate derived by Prigogine, used in the description of various processes in physics, chemistry and biology, and the maximum entropy production, used in many other cases and now considered more general. Both principles involve an extreme value of the rate of entropy production in an open system at the steady state under non-equilibrium conditions. In this paper, a link between these two approaches is developed and their synthesis with the constructal law is proposed. An application to ATP synthesis in anaerobic fermentation for biogas production is presented.

Entropy generation is analysed and obtained from the entropy balance for open systems, considering the lifetime of the natural real process. The Lagrangian approach is discussed in order to develop an analytical method to obtain the stationary states of the open irreversible systems. The stationary conditions of the open systems are obtained in relation to the entropy generation and its maximum principle. An analysis of both minimum and maximum entropy generation is proposed, suggesting that they are two different viewpoints of the same aspect: the first is related to the system, while the second is related to the interaction between the system and the environment.

One of the main challenges of the industry today is to face its impact on global warming considering that the greenhouse effect problem is not be solved completely yet. Magnetic refrigeration represents an environment-safe refrigeration technology. The magnetic refrigeration is analysed using the second law analysis in order to obtain a model for engineering application.

An increasing number of natural phenomena appear to deviate from standard statistical distributions. It has kindled interest in alternative formulation of statistical mechanics which should preserve most of the mathematical structures of the Boltzmann–Gibbs theory, while reproducing the phenomenology of the anomalous systems. The κ -theory has obtained a lot of results in the analysis of natural phenomena, but it was not extended to irreversible open systems. A modified κ -theory is proposed for its use in irreversible open systems.

The constructal theory is based on the thought that flow architecture is a consequence of a principle of maximization of flow access, in time, and in flow configuration that is free to be realised. The principle of maxima for the variation of the entropy due to irreversibility represents a general principle of investigation for the stability of open systems, by which it is possible to predict some macroscopic shapes, originated by the spatial organisation, in Nature, both in living and in non-living objects. Its statistical meaning has recently been introduced. Here a statistical and dynamical interpretation for the entropy due to irreversibility is proposed as a foundation of the constructal theory.

The balance of forces and processes between the system and the environment and the processes inside the system are the result of the flows of the quanta. Moreover, the transition between two thermodynamic states is the consequence of absorption or emission of quanta, but, during the transition, the entropy variation due to the irreversibility occurs and it breaks any symmetry of time. Consequently, the irreversibility is the result of a transition, a process, an interaction between the system and its environment. This interaction results completely time-irreversible for any real process because of irreversibility. As a consequence, a proof of the third law is obtained proving that the zero temperature state can be achieved only for an infinite work lost for dissipation or in an infinite time. The fundamental role of time both in equilibrium and in non equilibrium analysis is pointed out. Moreover, the non equilibrium temperature is related to the entropy generation and its fluctuation rate; indeed, non-stationary temperature means that the system has not yet attained free energy minimum state, i.e., the maximum entropy state; the consequence is that the zero temperature state can be achieved only for an infinite work lost for dissipation or in an infinite time. In engineering thermodynamics the efficiency is always obtained without any consideration on time, while, here, just the time is introduced as a fundamental quantity of the analysis of non equilibrium states.

Exergy is a fundamental quantity because it allows us to obtain information on the useful work obtainable in a process. The analyses of irreversibility are important not only in the design and development of the industrial devices, but also in fundamental thermodynamics and in the socio-economic analysis of municipality. Consequently, the link between entropy and exergy is discussed in order to link econophysics to the bio-chemical engineering thermodynamics. Last, this link holds to the fundamental role of fluxes and to the exergy exchanged in the interaction between the system and its environment. The result consists in a thermodynamic approach to the analysis of the unavailability of the economic, productive or social systems. The unavailability is what the system cannot use in relation to its internal processes. This quantity result is interesting also as a support to public manager for economic decisions. Here, the Alessandria Municipality is analyzed in order to highlight the application of the theoretical results.

To investigate biosystems, we propose a new thermodynamic concept that analyses ion, mass and energy flows across the cell membrane. This paradigm-shifting approach has a wide applicability to medically relevant topics including advancing cancer treatment. To support this claim, we revisit ‘Norton-Simon’ and evolving it from an already important anti-cancer hypothesis to a thermodynamic theorem in medicine. We confirm that an increase in proliferation and a reduction in apoptosis trigger a maximum of ATP consumption by the tumor cell. Moreover, we find that positive, membrane-crossing ions lead to a decrease in the energy used by the tumor, supporting the notion of their growth inhibitory effect while negative ions apparently increase the cancer’s consumption of energy hence reflecting a growth promoting impact. Our results not only represent a thermodynamic proof of the original Norton-Simon hypothesis but, more concretely, they also advance the clinically intriguing and experimentally testable, diagnostic hypothesis that observing an increase in negative ions inside a cell in vitro and inside a diseased tissue in vivo, may indicate growth or recurrence of a tumor. We conclude with providing theoretical evidence that applying electromagnetic field therapy early on in the treatment cycle may maximize its anti-cancer efficacy.

The relation between macroscopic irreversibility and microscopic reversibility is a present unsolved problem. Constructal law is introduced to develop analytically the Einstein’s, Schrödinger’s, and Gibbs’ considerations on the interaction between particles and thermal radiation (photons). The result leads to consider the atoms and molecules as open systems in continuous interaction with flows of photons from their surroundings. The consequent result is that, in any atomic transition, the energy related to the microscopic irreversibility is negligible, while when a great number of atoms (of the order of Avogadro’s number) is considered, this energy related to irreversibility becomes so large that its order of magnitude must be taken into account. Consequently, macroscopic irreversibility results related to microscopic irreversibility by flows of photons and amount of atoms involved in the processes.

The consequences of the interactions of electromagnetic waves, as used in conventional MRI technology, with human cells are not fully understood. To analyze these interactions, a novel thermodynamic approach is presented that is based on the relationship between electromagnetic and thermodynamic quantities. The theoretical results indicate that the waves’ impact is largest at high magnetic field strengths and at low frequencies. This is the first step towards a clinically useful framework to quantitatively assess MRI impact including a potential trade-off between the desired increase in spatial resolution that higher magnetic field strengths yield for diagnostic purposes and the danger this may pose for cell membranes, and by extension, for the tissues investigated.

Cells are complex thermodynamic systems. Their energy transfer, thermo-electro-chemical processes and transports phenomena can occur across the cells membranes, the border of the complex system. Moreover, cells can also actively modify their behaviours in relation to any change of their environment. All the living systems waste heat, which is no more than the result of their internal irreversibility. This heat is dissipated into their environment. But, this wasted heat represents also a sort of information, which outflows from the cell towards its environment, completely accessible to any observer. The analysis of irreversibility related to this wasted heat can represent a new useful approach to the study of the cells behaviour. This approach allows us to consider the living systems as black boxes and analyse only the inflows and outflows and their changes in relation to any environmental change. This analysis allows also the explanation of the effects of electromagnetic fields on the cell behaviour.

The entropy variation due to irreversibility is considered to deduce a principle of stability for open systems. To demonstrate this, thermodynamic Lagrangian and the minimum action principle are used.

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 aim of this work was to evaluate differences in energy flows between normal and immortalized cells when these distinct biological systems are exposed to environmental stimulation. These differences were considered using a constructal thermodynamic approach and were subsequently verified experimentally. The application of constructal law to cell analysis led to the conclusion that temperature differences between cells with distinct behaviour can be amplified by interaction between cells and external fields. Experimental validation of the principle was carried out on two cellular models exposed to electromagnetic fields. By infrared thermography we were able to assess small changes in heat dissipation measured as a variation in cell internal energy. The experimental data thus obtained are in agreement with the theoretical calculation, because they show a different thermal dispersion pattern when normal and immortalized cells are exposed to electromagnetic fields. By using two methods that support and validate each other, we have demonstrated that the cell/environment interaction can be exploited to enhance cell behavior differences, in particular heat dissipation. We propose infrared thermography as a technique effective in discriminating distinct patterns of thermal dispersion and therefore able to distinguish a normal phenotype from a transformed one.

Is there a link between the macroscopic description of the irreversibility and microscopic behaviour of the systems? Transfer of the exergy, i.e., consumption of free energy will keep the system away from a stable equilibrium. So entropy generation results from the redistribution of energy, momentum, mass and charge. Moreover, irreversible consumption of free energy was underlined to create time’s arrow. This concept represents the essence of the thermodynamic approach to irreversibility. The analysis developed in this paper points out that the principle of maximum of entropy generation and the least action can be recognized as the only single law. Quanta are exchanged between a system and its surroundings. Each quantum carries energy. The natural behaviour of the open systems is ascribed to the decrease of free energy in the least time, which can be related to the extremum entropy generation theorem. Irreversibility is the result of the interaction between systems and their environment with the consequence time symmetry breaking. The fundamental result of this paper is to introduce a link between the global analysis of irreversibility and Noether’s results.

In the last twenty years, the entropy generation approach has been developed in order to analyse complex systems (open and irreversible). The first applications of the entropy generation extrema theorem were developed on energy systems, but recently, it has also been extended to biological systems in order to evaluate their stationary states. In this paper, the entropy generation is analyzed in relation to the hydrological and hydraulic behaviour of rivers. An example is developed on the Tanaro River in Piedmont (Italy)

Molecular machines do not apparently satisfy the second law of thermodynamics. This holds to the Loschmidt paradox. Boltzmann introduced the irreversible evolution of any system towards a state of mechanical and thermal equilibrium. He expressed this result in his H-theorem. Loschmidt objected that the Boltzmann's result was inconsistent because it was obtained by using a time-symmetric dynamics, in contrast with the time asymmetry of the result. In this letter we show how these two problems can be related to the Gouy–Stodola theorem and to the interactions between open systems or open subsystems in the case of closed or isolated systems.

Pumping protons across a membrane was a critical step at the origin of life on earth, and it is still performed in all living organisms, including in human cells. Proton pumping is paramount to keep normal cells alive, e.g. for lysosomal digestion and for preparing peptides for immune recognition, but it goes awry in cancer cells. They acidify their microenvironment hence membrane voltage is lowered, which in turn induces cell proliferation, a hallmark of cancer. Proton pumping is achieved by means of rotary motors, namely vacuolar ATPases (V-ATPase), which are present at many of the multiple cellular interfaces. Therefore, we undertook an examination of the thermodynamic properties of V-ATPases. The principal result is that the V-ATPase-mediated control of the cell membrane potential and the related and consequent environmental pH can potentially represent a valuable support strategy for anticancer therapies. A constructal theory approach is used as a new viewpoint to study how V-ATPase can be modulated for therapeutic purposes. In particular, V-ATPase can be regulated by using external fields, such as electromagnetic fields, and a theoretical approach has been introduced to quantify the appropriate field strength and frequency for this new adjuvant therapeutic strategy.

Delbruck scattering, which is the elastic scattering of a photon in a Coulomb field, is of interest both as an observable high-order non-linear process in quantum electrodynamics and as an interfering process in studies of nuclear structure. This process has been extensively investigated in the past from theoretical and computational points of view. In this paper, attention is mainly focused on the theoretical features and, in particular, the dispersion relation approach and a critical review of the numerical evaluations of the first-order Born approximation cross-section is presented. Applications and limits of these results are discussed in comparison with experimental data on elastic photon scattering by medium-and heavy-mass nuclei and theoretical models of nuclear structure.

In this paper an analysis of the Stirling cycle in thermoeconomic terms is developed using the entropy generation. In the thermoeconomic optimization of an irreversible Stirling heat pump cycle the F function has been introduced to evaluate the optimum for the higher and lower sources temperature ratio in the cycle: this ratio represents the value which optimizes the cycle itself. The variation of the function F is proportional to the variation of the entropy generation, the maxima and minima of F has been evaluated in a previous paper without giving the physical foundation of the method. We investigate the groundwork of this approach: to study the upper and lower limits of F function allows to determine the cycle stability and the optimization conditions. The optimization consists in the best COP at the least cost. The principle of maximum variation for the entropy generation becomes the analytic foundation of the optimization method in the thermoeconomic analysis for an irreversible Stirling heat pump cycle. Pacs: 89.65.G, 05.70 keywords: entropy generation, finite time Thermodynamics, Stirling cycle, Thermodynamic optimization., 9 pages, presented to the International Conference NEXT2005, Creta, August 2005

Stochastic differential equations are important to model many complex systems. The Fokker–Planck equation is fundamental in statistical thermodynamic analysis and in the study of fluctuations in complex systems. Entropy generation is a fundamental quantity in the analysis of irreversibility. This paper develops a link between the Fokker–Planck equation and entropy generation. The result suggests linking the entropy generation approach also to statistical processes.

Cells can be regarded as engines that execute a series of chemical reactions. A malignant cell, that is, a cancerous cell, can be described as an open complex dynamic and self-organising system. The entropy generation approach has been used to evaluate the stationary states for cells in relation to the global results of the cell biophysical and biochemical processes. Then, an entropy generation approach can been used to evaluate malignant behaviour in terms of thermal, chemical and transport processes. A numerical evaluation of the mean value of the entropy generation for cancer is developed. A possible therapy against cancer has been suggested by using molecular thermalisation.

Progress always requires energy. Up today, the energy needs have been provided by combustion of fossil fuels and this has increased the air pollution and the emission of greenhouse gasses. Consequently, the greenhouse emission problem could represents a concrete opportunity to promote the high-efficiency design of conventional plants, but also a new approach to energy systems and the consequent dissemination of advanced technologies. One of the most promising energy conversion technology is the fuel cell because it is an electrochemical device in which the chemical energy is directly converted into electrical energy, with low environmental impact. In this paper the losses of the fuel cells has been analysed.

Cells are chemical engines in which specific ordered chemical reactions occur. Cancer can be described as an open complex dynamic and self-organizing system. Entropy generation approach has been used to evaluate the biochemical and biophysical conditions of the stationary states for tumoral cells, in relation to the transport processes through their membrane. The tumoral systems can assume all the values of volume, temperature, chemical reaction rate and the time of chemical reaction, in the range of stationary conditions. This range can be evaluated by the principle of extrema variation of the entropy generation. Outside this range, cancer cannot develop and dies. The geometrical characteristics are fundamental in the growth of cancer. The fractal dimensions are discussed in this analysis and the geometry of cancer is related to the entropy generation. A possible anticancer thermodynamic approach has been suggested.

Biomechanical analyses of DNA have pointed out the connections among forces, thermodynamics and kinetics. The entropy generation approach has been suggested as a thermodynamic approach to evaluate the accessible states for cancer systems, in relation to their specific thermodynamic quantities, including mechanical properties. In this paper, a theoretical approach for the thermodynamic evaluation of the nano-behaviour of the cell wall is suggested. The aim is to provide theoretical bases to the analysis of cells and their properties by applying the thermodynamic approach to irreversibility.

In photofission a lot of studies have been made to analyze the energy of the nuclei to understand their inner structure. The relevance of the excitation function has been pointed out. The Hamiltonian of interaction for the photofission was deduced and connected to the excitation function.

Exergy and entropy generation analysis of the open systems allows to obtain a measure of how far the open real systems deviate from equilibrium with their environment. A link between entropy generation maximum principle and the exergy analysis of engineering and natural systems is suggested in order to use the exergy and entropy approach to improve the renewable energy systems.

Recently, in theoretical biology and in biophysical engineering the entropy production has been verified to approach asymptotically its maximum rate, by using the probability of individual elementary modes distributed in accordance with the Boltzmann distribution. The basis of this approach is the hypothesis that the entropy production rate is maximum at the stationary state. In the present work, this hypothesis is explained and motivated, starting from the entropy generation analysis. This latter quantity is obtained from the entropy balance for open systems considering the lifetime of the natural real process. The Lagrangian formalism is introduced in order to develop an analytical approach to the thermodynamic analysis of the open irreversible systems. The stationary conditions of the open systems are thus obtained in relation to the entropy generation and the least action principle. Consequently, the considered hypothesis is analytically proved and it represents an original basic approach in theoretical and mathematical biology and also in biophysical engineering. It is worth remarking that the present results show that entropy generation not only increases but increases as fast as possible.

Entropy generation approach has been developed in order to use it for the analysis of complex systems with particular regards to biological systems in order to evaluate their stationary states. The entropy generation is related to the transport processes related to energy flows. Moreover, cancer can be described as an open complex dynamic and self-organizing system. Using the entropy generation approach it is possible to point out different chemical reaction time between normal and solid cancer cells.

In 1824, Carnot proposed a cycle operating on reversibility principles. He proved that there exists an upper limit of the efficiency of this cycle and this limit is also the upper limit for any real process. The irreversibility related to the finite-time and the finite-size constraints are fundamental for the optimization of any real thermodynamic system. It has been pointed out how fundamental is the interaction between any open system and its surroundings. The meaning of the Carnot efficiency is that even in the ideal condition, when there is no dissipation, there exists something that does not allow the system to convert all the energies absorbed in work. The aim of this paper is to show why this happens, starting from a variational approach of thermodynamics.

A recent analysis of the Carnot’s results has pointed out that natural systems may not convert all the inflow of energy to do work. Some energy will be used to maintain the systems’ internal processes. These exergy flows appear as the heat exchanged with a second thermostat of a thermodynamic engine. In this Letter a calculus of this internal irreversibility is developed using the entropy generation approach. The obtained results are exemplified in the analysis of superconductivity.

Introduction The temperature difference between normal and cancer cells was proven to be one of the fundamental quantities in the cancer growth. The allosteric transition is a conformational change of a protein conditioned to the binding at a specific site; in an enzyme, the two different parts can oscillate around their equilibrium state: if the temperature increases these parts increase their oscillating amplitudes, decreasing in their functionality. The Hypothesis The entropy generation approach has been used in order to evaluate the stationary conditions of tumoral cells, in relation to the transport processes. The tumoral systems can assume all the values of volume, temperature, chemical reaction rate and the time of chemical reaction, inside its stationary range of variation: outside of this range, the cancer cannot develop and dies. Evaluation of Hypothesis The control of these physical-chemical processes can be obtained by using molecular refrigerators in order to control the temperature of the cells. The aim is to maintain the temperature of a normal cell and not to allow the cell to increase it temperature up to the cancer state. The useful effect consists in obtaining conformational changes in a protein by supplying free energy on one site of the molecule, required for driving the cooling process. This thermalization is suggested as an anticancer therapy. The temperature variation is evaluated by using the entropy generation approach. Conclusion The results obtained represent a new approach to the study of the cancer and to the development of new anticancer therapy, based on molecular refrigeration

Entransy is a function recently introduced in thermodynamics. This function is analyzed critically in relation to the classical thermodynamic approach in order to understand its physical fundamentals. The crucial problem is that thermodynamic analysis shows that entransy does not contain any new information in comparison with a classical thermodynamic analysis of systems. Furthermore, entransy dissipation analysis is a duplicate of entropy generation analysis.

The calculus of variations can be applied in thermodynamics obtaining both local and global analysis for the thermodynamical systems. Gyarmati’s principle is demonstrated to be the mathematical fundamental of the theorem of maximum for the entropy of the open systems. This last theorem is demonstrated for a general thermodynamical transformation, and also when chemical reactions can occur.

The recent developments in thermodynamic analysis of irreversibility for open systems represent an important result useful in the study of brain, both in relation to its neurobiology and to its diseases. In this paper the extrema entropy generation principle is suggested as a new powerful approach to the study of brain.

In 2009 it was pointed out that, in nuclear photofission, a rigorous thermodynamic approach must be introduced in the thermodynamic analysis of nuclear photofission and the first aim is to obtain a relation between the nuclear temperature definition and the excitation function, introduced in 1992. An analysis of the nuclear temperature is developed. The aim is to define the nuclear temperature using the photofission probability function, in order to link it to the inner properties of the nuclei.

A relation for the proton-neutron pair (pn-pair) mass inside the nucleus is obtained by a statistical model in the Quasi-Deuteron (QD) energy region.

The open system has been proved to be a system with perfect accessibility represented as a probability space in which is defined a P A -measure. But, the P A -measure is not yet known; consequently, it is difficult to develop the statistical thermodynamics for an irreversible system. Here its integral expression is obtained in order to its use in the statistical thermodynamic analysis of the complex and irreversible systems.

Hydrodynamic cavitation is analysed by a global thermodynamics principle following an approach based on the maximum irreversible entropy variation that has already given promising results for open systems and has been successfully applied in specific engineering problems. In this paper we present a new phenomenological method to evaluate the conditions inducing cavitation. We think this method could be useful in the design of turbo-machineries and related technologies: it represents both an original physical approach to cavitation and an economical saving in planning because the theoretical analysis could allow engineers to reduce the experimental tests and the costs of the design process.

The problem of irreversibility is difficult and part of this difficulty is due to dealing with the statistical mechanics of a large number of particles. The ergodic theory, founded on the link between thermodynamics and its statistical probability, introduced the ergodic theorem that consists of the equality of microcanonical phase average and the time average of the observables. Moreover, a global approach has been introduced, starting from non-equilibrium thermodynamics and obtaining a general principle of investigation, the principle of maximum entropy generation for the open systems. Here, a general approach to the investigation of irreversible systems and the application of entropy generation to the study of the dynamical systems will be developed.