Heat is defined in classical thermodynamics as an energy transfer mechanism, but its fundamental nature is not yet fully understood. After reviewing previous macroscopic, mesoscopic, and microscopic approaches to heat, we propose a fundamental definition of heat in terms of a fully detailed microscopic description and apply this definition to a one-component gas with constant composition for comparison with the usual macroscopic formulae. Using the new definition, we debunk common claims in the literature that associate heat with our ignorance of the microscopic details of a thermodynamic system.

If a piece of conducting material has a temperature difference between its two ends, an electromotive force is observed between the ends with the hotter end being positive and the other negative. This is the Seebeck effect. The emf is dependent only on the temperature difference and the type of conductor material. Current physics only mentions the emf of the Seebeck effect, but has ignored another significant fact about the Seebeck effect. Besides the observed emf, the Seebeck effect causes a radiation energy current flow within the conductor from the hotter end towards the cooler end. The operation of a thermocouple electric cell relies on the Seebeck effect. An analysis the operation of such a cell shows that energy transmission by current-carrying conductors has nothing to do with the magnetic fields surrounding the conductor; the actual physical mechanism of energytransmission is by photon energy current within the body of the conductor.

We propose concept of equation of state (EoS) effect structure in form of diagrams and rules. This concept helps justifying EoS status of an empirical relation. We apply the concept to closed system of consumers and we are able to formulate its EoS. According to the new concept, EoS are classified into three classes. Manifold space of thermodynamics formulation of demand-side economics is identified. Formal analogies of thermodynamics and economics consumers' system are made. New quantities such as total wealth, generalized utility and generalized consumer surplus are defined. Microeconomics' concept of consumer surplus is criticized and replaced with generalized consumer surplus. Smith's law of demand is included in our new paradigm as a specific case resembling isothermal process. Absolute zero temperature state resembles the nirvana state in Buddhism philosophy. Econometric modelling of consumers' EoS is proposed at last.

The universal unitary principle of logic test is used to test the mathematical reasoning of pressure equation of ideal gas, and a negative conclusion is given. The study found that, the classical molecular kinetic theory establishes a physical model of the uniform motion of a molecule under the action of an equivalent constant force, which violates the principle of mechanics, and the classical equations for the pressure and temperature of ideal gas derived from such a model are all incorrect. Here we set up a variety of physical models of molecular interaction in accordance with the principle of mechanics, and consistently derive the modified equation of ideal gas pressure. It is proved that the pressure of ideal gas is equal to the molecular energy in unit volume, and the thermodynamic temperature of ideal gas is equal to the quotient of molecular average kinetic energy and Boltzmann constant. Reasoning accords with the unitary principle. The inferences of these different models accords with the unitary principle. Furthermore, the problem of the definite solution of the gas molecular velocity distribution function satisfying the limit condition of light speed is proposed. Finally, the experimental suggestion to verify the theoretical gas temperature correction equation is given.

Motivated by the well-known contradiction of special relativity and the heat equation, a wave equation for temperature scalar field is presented that also resolves the old issue of (Lorentz) transformation of temperature and entropy. As an inductive consequence it is proposed that single particles posses entropy.

We derive a lower limit $\Delta H_{vap}^Z $ for the latent heat of vaporization $\Delta H_{vap}$ with respect to the pressure and the volume change of the phase transition from the study of a heat engine using liquid-gas as working fluid with an infinitesimal variation of the temperature $\delta T$ and an infinitesimal variation of the pressure $\delta P$ and in the vanishing limit of the massive flow rate $Q_m$. We calculate the latent heat index $h^Z= \Delta H_{vap}^Z/\Delta H_{vap}$ of few gas and at few different pressures $P$. Finally, we consider the latent heat index limit $h^Z_{cr}$ as the temperature $T$ approaches the critical temperature $T_{cr}$.

With the increasing adoption of renewable energy sources by domestic users, decentralisation of the grid is fast becoming a reality. Distributed generation is an important part of a decentralised grid. This approach employs several small-scale technologies to produce electrical energy close to the end users or consumers. The higher reliability of these systems proves to be of advantage when compared to traditional generation systems. Multi-Input Converters (MICs) perform a decisive function in Distributed Energy Resources (DERs). Making use of such MICs prove to be beneficial in terms of size, cost, number of components used, efficiency and reliability as compared to using several independent converters. This thesis proposes a double input DC-DC converter which makes use of a quasi Y-source converter in tandem with a boost converter. The quasi Y-source converter has the advantage of having a very high gain for low duty cycles. The associated operating modes are analysed and the operation of the MIC is verified using simulation result. A hardware prototype is built for large signal analysis in open loop. Different loads are applied and the efficiency of the MIC as a whole as well as the load sharing between the different sources is investigated.

Jeremy England proposed in his “Statistical physics of self-replication” that energy dispersion drives evolution. Such is the explanatory power of his theory that we build on it to rethink the relationship between life and entropy as handed to us by Schodinger, to find a place for the origin and evolution of life within the cosmos, to explain the Cambrian Explosion and the Mass Extinctions from an entropic perspective, hence the title, and finally, to find a way out of the gloom and doom of global warming.

Mechanisms to use nanoparticles to separate sunlight into photovoltaic useful range and thermally useful range to increase the efficiency of solar cells and to dissipate heat radiatively are discussed based upon lessons we learnt from photosynthesis. We show that the dual-band maxima in the absorption spectrum of bacterial light harvestors not only are due to the bacteriochlorophylls involved but also come from the geometry of the light harvestor. Being able to manipulate these two bands arbitrarily enables us to fabricate the nanoparticles required. Such mechanisms are also useful for the design of remote power charging and light sensors.

Since Dr. Sheehan has published his discovery of the solid-state Maxwell demon (SSMD) many people have attacked the concept, simply because it violates the 2nd law of thermodynamics, which they consider to be sacrosanct and inviolable. One of the opponents is Dr. D’Abramo who attempted to debunk the principle in several papers. His main objection against the principle of the device is that according to him no electrostatic field can exist within the vacuum gap of the SSMD in equilibrium. In the present paper we will refute his arguments that he presented in the quoted publication.

Kirchhoff’s law of thermal emission asserts that, given sufficient dimensions to neglect diffraction, the radiation contained within arbitrary cavities must always be black, or normal, dependent only upon the frequency of observation and the temperature, while independent of the nature of the walls. In this regard, it is readily apparent that all cavities appear black at room temperature within the laboratory. However, two different causes are responsible: 1) cavities made from nearly ideal emitters self-generate the appropriate radiation, while 2) cavities made from nearly ideal reflectors are filled with radiation contained in their surroundings, completely independent of their own temperature. Unlike Kirchhoff’s claims, it can be demonstrated that the radiation contained within a cavity is absolutely dependent on the nature of its walls. Real blackbodies can do work, converting any incoming radiation or heat to an emission profile corresponding to the Planckian spectrum associated with the temperature of their walls. Conversely, rigid cavities made from perfect reflectors cannot do work. The radiation they contain will not be black but, rather, will reflect any radiation which was previously incident from the surroundings in a manner independent of the temperature of their walls.

The Stirling thermodynamic heat engine cycle is modified, where instead of an ideal gas, a real, supercritical, monatomic working fluid subjected to intermolecular attractive forces is used. The potential energy of real gases is redefined to show it decreasing with temperature as a result of the attractive Keesom forces, which are temperature dependent. This new definition of potential energy is used to thermodynamically design a Stirling cycle heat engine with supercritical xenon gas, and an engine efficiency that exceeds the Carnot efficiency is demonstrated. The change in internal energy predicted is compared to experimental measurements of condensing steam, xenon, argon, krypton, nitrogen, methane, ethane, propane, normal butane, and iso-butane, and the close match validates this new definition of temperature-dependent real gas potential energy, as well as the thermodynamic feasibility of the modified supercritical Stirling cycle heat engine.

Kirchhoff’s Law of Thermal Emission asserts that, given sufficient dimensions to neglect diffraction, the radiation contained within arbitrary cavities must always be black, or normal, dependent only upon the frequency of observation and the temperature, while independent of the nature of the walls. With this in mind, simple tests were devised to demonstrate that Kirchhoff’s Law is invalid. It is readily apparent that all cavities appear black at room temperature within the laboratory. However, two completely different causes are responsible: 1) cavities made from good emitters self-generate the appropriate radiation and 2) cavities made from poor emitters are filled with radiation already contained in the room, completely independent of the temperature of the cavity. The distinction between these two scenarios can be made by placing a heated object near either type of cavity. In the first case, the cavity emission will remain essentially undisturbed. That is because a real blackbody can do work, instantly converting incoming radiation to an emission which corresponds to the temperature of its walls. In the second case, the cavity becomes filled with radiation which is not characteristic of its own temperature. Contrary to current belief, cavity radiation is entirely dependent on the nature of the walls. When considering a perfect reflector, the radiation will not be black but, rather, will reflect any radiation which was previously incident upon the cavity from the surroundings. This explains why microwave cavities are resonant, not black, and why it is possible to acquire Ultra High Field Magnetic Resonance Imaging (UHFMRI) images using cavity resonators. Conversely, real blackbodies cannot contain any radiation other than that which is characteristic of the temperature of their walls, as shown in Planck’s equation. Blackbody radiation is not universal, Kirchhoff’s Law is false, and cavity radiation is absolutely dependent on the nature of the walls at every frequency of observation. Since they were derived from this law, the concepts of Planck time, Planck temperature, Planck length, and Planck mass are not universal and are devoid of any fundamental meaning in physics.

The Stirling thermodynamic heat engine cycle is modified, where instead of an ideal gas, a real, monatomic working fluid is used, with the engine designed so that the isothermal compression starts off as a saturated gas, and ends as a mixed-phase fluid. This cycle takes advantage of the attractive intermolecular Van der Waals forces of the working fluid to assist in compressing the working fluid partially into a liquid, reducing the input compression work and increasing the overall heat engine efficiency to exceed that of the Carnot efficiency.

This study considers an appropriate expression to estimate the output power of solar chimney power plant systems (SCPPS). Recently several mathematical models of a solar chimney power plant were derived, studied for a variety of boundary conditions, and compared against CFD calculations. An important concern for modeling SCPPS is about the accuracy of the derived pressure drop and output power equation. To elucidate the matter, axisymmetric CFD analysis was performed to model the solar chimney power plant and calculate the output power for diffrent available solar irradiation. Both analytical and numerical results were compared against the available experimental data from the Manzanares power plant. We also evaluated the fidelity of the assumptions underlying the derivation and present reasons to believe that some of the derived equations, specially the power equation in this model, may require a correction to be applicable in more realistic conditions. This paper provides an approach to estimate the output power with respect to radiation available to the collector.

In the new approach to the diffusion problem conventional statistical derivation is reconsidered deterministically using the partition function for thermal velocities. The resulting relation for time evolution of particle distribution is an integro-differential equation. Its first approximation provides the conventional partial differential equation - the second Fick's law with the diffusion transport coefficient proportional to the temperature.

A new definition of heat for open systems, with a number of advantages over previous definitions, was introduced in [2013}; Int. J. Therm., 16(3), 102--108]. We extend the previous work by analyzing the production of entropy and showing that the new definition of heat appears naturally as the proper flow [«flux density»] conjugate to the gradient of temperature, with the previous definitions only considering a subset of the physical effects associated to this gradient. We also revisit the transfer of heat in multicomponent systems, confirming the identity derived in the previous work for the identification of thermal effects associated to each one of the chemical potentials in the system. The new definition of heat was previously obtained within the scope of the traditional thermodynamics of irreversible processes (TIP), which has a limited field of applicability to macroscopic systems with no too strong gradients and not too fast processes. We extend now the new definition of heat to more general situations and to the quantum level of description using a standard non-commutative phase space, with the former TIP-level definition recovered from partial integration.

We focus on the symptom of hypothalamus controlled fever, which is in fact a problem related to non-equilibrium system. Since live human body has constant temperature, whose dissipation is easy to be figured out by observation, it is a suitable candidate for non-equilibrium system to study. In our paper, human body is regarded as a 2-compartment-system: one is the chemical-reaction network, the other is observed by mechanical motion which means the vital signs apart from body temperature. Van der Pol model is used to describe the overall effect of chemical reaction network in human body. When the parameter of mathematical model is set to guarantee the mathematical model to be in limit cycle oscillation state, the energy absorbtion and releasing is computed. With the help of body temperature, which can be observed, the energy metabolism of overall effect of chemical reaction network is figured out. We have figured out the conditions when human is at healthy and fever how the mathematical respond. This response is just the overall effect of chemical reaction network. This research may be capable of answering the question whether fever is a kind of illness or some response of body to maintain its life? From our study, hypothalamus controlled fever is beneficial to maintain life.

Previous approaches of emergent thermalization for condensed matter based on typical wavefunctions are extended to generate an intrinsically quantum theory of gases. Gases are fundamentally quantum objects at all temperatures, by virtue of rapid delocalization of their constituents. When there is a sufficiently broad spread in the energy of eigenstates, a well- defined temperature is shown to arise by photon production when the samples are optically thick. This produces a highly accurate approximation to the Planck distribution so that thermalization arises from the initial data as a consequence of purely quantum and unitary dynamics. These results are used as a foil for some common hydrodynamic theory for ultracold gases. It is suggested here that strong history dependence typically remains in these gases and so limits the validity of thermodynamics in their description. These problems are even more profound in the extension of hydrodynamics to such gases when they are optically thin, even when their internal energy is not low. We investigate rotation of elliptically trapped gases and consistency problems with deriving a local hydrodynamic approach. The presence of vorticity that is “hidden” from order parameter approaches is discussed along with some buoyancy intrinsically associated with vorticity that gives essential quantum corrections to gases in the regimes where standard perturbation approaches to the Boltzmann equations are known to fail to converge. These results suggest that studying of trapped gases in the far from ultracold regions may yield interesting results not described by classical hydrodynamics.

Assuming the existence of a fundamental thermodynamic relation, the classical thermodynamics of a black hole with mass and angular momentum is given. New definitions of the response functions and $TdS$ equations are introduced and mathematical analogous of the Euler equation and Gibbs-Duhem relation are founded. Thermodynamic stability is studied from concavity conditions, resulting in an unstable equilibrium at all the domain except for a region of local stable equilibrium. The Maxwell relations are written, allowing to build the thermodynamic squares. Our results shown an interesting analogy between thermodynamics of gravitational and magnetic systems.

In this work, the development of solar theory is followed from the concept that the Sun was an ethereal nuclear body with a partially condensed photosphere to the creation of a fully gaseous object. An overview will be presented of the liquid Sun. A powerful lineage has brought us the gaseous Sun and two of its main authors were the direct scientific descendants of Gustav Robert Kirchhoff: Franz Arthur Friedrich Schuster and Arthur Stanley Eddington. It will be discovered that the seminal ideas of Father Secchi and Hervé Faye were not abandoned by astronomy until the beginning of 20th century. The central role of carbon in early solar physics will also be highlighted by revisiting George Johnstone Stoney. The evolution of the gaseous models will be outlined, along with the contributions of Johann Karl Friedrich Zöllner, James Clerk Maxwell, Jonathan Homer Lane, August Ritter, William Thomson, William Huggins, William Edward Wilson, George Francis FitzGerald, Jacob Robert Emden, Frank Washington Very, Karl Schwarzschild, and Edward Arthur Milne. Finally, with the aid of Edward Arthur Milne, the work of James Hopwood Jeans, the last modern advocate of a liquid Sun, will be rediscovered. Jeans was a staunch advocate of the condensed phase, but deprived of a proper building block, he would eventually abandon his non-gaseous stars. For his part, Subrahmanyan Chandrasekhar would spend nine years of his life studying homogeneous liquid masses. These were precisely the kind of objects which Jeans had considered for his liquid stars.

In this work, an introductory exposition of the laws of thermodynamics and radiative heat transfer is presented while exploring the concepts of the ideal solid, the lattice, and the vibrational, translational, and rotational degrees of freedom. Analysis of heat transfer in this manner helps scientists to recognize that the laws of thermal radiation are strictly applicable only to the ideal solid. On the Earth, such a solid is best represented by either graphite or soot. Indeed, certain forms of graphite can approach perfect absorption over a relatively large frequency range. Nonetheless, in dealing with heat, solids will eventually sublime or melt. Similarly, liquids will give way to the gas phase. That thermal conductivity eventually decreases in the solid signals an inability to further dissipate heat and the coming breakdown of Planck’s law. Ultimately, this breakdown is reflected in the thermal emission of gases. Interestingly, total gaseous emissivity can decrease with increasing temperature. Consequently, neither solids, liquids, or gases can maintain the behavior predicted by the laws of thermal emission. Since the laws of thermal emission are, in fact, not universal, the extension of these principles to non-solids constitutes a serious overextension of the work of Kirchhoff, Wien, Stefan and Planck.