Second Principles Of Thermodynamics Research Articles

Discretisations of mixed-dimensional Thermo-Hydro-Mechanical models preserving energy estimates

In this study, we explore mixed-dimensional Thermo-Hydro-Mechanical (THM) models in fractured porous media accounting for Coulomb frictional contact at matrix fracture interfaces. The simulation of such models plays an important role in many applications such as hydraulic stimulation in deep geothermal systems and assessing induced seismic risks in CO2 storage. We first extend to the mixed-dimensional framework the thermodynamically consistent THM models derived in [19] based on first and second principles of thermodynamics. Two formulations of the energy equation will be considered based either on energy conservation or on the entropy balance, assuming a vanishing thermo-poro-elastic dissipation. Our focus is on space time discretisations preserving energy estimates for both types of formulations and for a general single phase fluid thermodynamical model. This is achieved by a Finite Volume discretisation of the non-isothermal flow based on coercive fluxes and a tailored discretisation of the non-conservative convective terms. It is combined with a mixed Finite Element formulation of the contact-mechanical model with face-wise constant Lagrange multipliers accounting for the surface tractions, which preserves the dissipative properties of the contact terms. The discretisations of both THM formulations are investigated and compared in terms of convergence, accuracy and robustness on 2D test cases. It includes a Discrete Fracture Matrix model with a convection dominated thermal regime, and either a weakly compressible liquid or a highly compressible gas thermodynamical model.

Experimental investigation of the evacuated tube under Iraq weather conditions utilizing first and second law efficiency

This article presents the results of a field test of an evacuated-tube solar water heater and provides an analysis of those results. The first and second principles of thermodynamics were used to analyse the performance of the evacuated tube solar water heater. Between 6:00 PM and 6:00 AM before each test, the whole tank's water supply was renewed. After 24 hours of operation in the month of November, the water temperature in the tank reached 33.5 degrees Celsius. The ETSWH achieved an efficiency of 76.1% according to the first law, while the second law efficiency was 5.2%. Morning tank water temperatures averaged 33.5 degrees Celsius. The ETSWH's daily energy efficiency was 57.2%, and its exergy use efficiency was 4.48 %.

A New Thermodynamically Compatible Finite Volume Scheme for Magnetohydrodynamics

In this paper we propose a novel thermodynamically compatible finite volume scheme for the numerical solution of the equations of magnetohydrodynamics (MHD) in one and two space dimensions. As shown by Godunov in 1972, the MHD system can be written as overdetermined symmetric hyperbolic and thermodynamically compatible (SHTC) system. More precisely, the MHD equations are symmetric hyperbolic in the sense of Friedrichs and satisfy the first and second principles of thermodynamics. In a more recent work on SHTC systems, \cite{Rom1998}, the entropy density is a primary evolution variable, and total energy conservation can be shown to be a \textit{consequence} that is obtained after a judicious linear combination of all other evolution equations. The objective of this paper is to mimic the SHTC framework also on the discrete level by directly discretizing the \textit{entropy inequality}, instead of the total energy conservation law, while total energy conservation is obtained via an appropriate linear combination as a \textit{consequence} of the thermodynamically compatible discretization of all other evolution equations. As such, the proposed finite volume scheme satisfies a discrete cell entropy inequality \textit{by construction} and can be proven to be nonlinearly stable in the energy norm due to the discrete energy conservation. In multiple space dimensions the divergence-free condition of the magnetic field is taken into account via a new thermodynamically compatible generalized Lagrangian multiplier (GLM) divergence cleaning approach. The fundamental properties of the scheme proposed in this paper are mathematically rigorously proven. The new method is applied to some standard MHD benchmark problems in one and two space dimensions, obtaining good results in all cases.

Physically Consistent Neural ODEs for Learning Multi-Physics Systems*

Despite the immense success of neural networks in modeling system dynamics from data, they often remain physics-agnostic black boxes. In the particular case of physical systems, they might consequently make physically inconsistent predictions, which makes them unreliable in practice. In this paper, we leverage the framework of Irreversible port-Hamiltonian Systems (IPHS), which can describe most multi-physics systems, and rely on Neural Ordinary Differential Equations (NODEs) to learn their parameters from data. Since IPHS models are consistent with the first and second principles of thermodynamics by design, so are the proposed Physically Consistent NODEs (PC-NODEs). Furthermore, the NODE training procedure allows us to seamlessly incorporate prior knowledge of the system properties in the learned dynamics. We demonstrate the effectiveness of the proposed method by learning the thermodynamics of a building from the real-world measurements and the dynamics of a simulated gas-piston system. Thanks to the modularity and flexibility of the IPHS framework, PC-NODEs can be extended to learn physically consistent models of multi-physics distributed systems.

Energy and Exergetic Evaluation of Thermodynamic Systems Applied to Water Heating at Low Temperatures

Given the changes in human needs in the 21st century, which are increasingly dependent on different energy sources, this work aims to compare the energetic and exergetic efficiency of a shower heated by electric resistance and a solar heater. The method employed is based on the first and second principles of thermodynamics. We found that, under conditions at low heating temperature, the shower has better exergetic efficiency due to solar heating when compared to electrical energy since the destroyed exergy is lesser in the solar heater. Energy efficiency (quantitative aspect) is bigger in electrical resistance because presents better performing energy than solar energy. Therefore, for the final use, of heating at low temperatures, the solar heater is recommended from the thermodynamic perspective.

Energy and Exergetic Evaluation of Thermodynamic Systems Applied to Water Hearing at Low Temperatures

Given the changes in human needs in the 21st century, which are increasingly dependent on different energy sources, this work aims to compare the energetic and exergetic efficiency of a shower heated by electric resistance and a solar heater. The method employed is based on the first and second principles of thermodynamics. We found that, under conditions at low heating temperature, the shower has better exergetic efficiency due to solar heating when compared to electrical energy since the destroyed exergy is lesser in the solar heater. Energy efficiency (quantitative aspect) is bigger in electrical resistance because presents better performing energy than solar energy. Therefore, for the final use, of heating at low temperatures, the solar heater is recommended from the thermodynamic perspective.

Is accounting a natural science?

Purpose: This paper verifies the hypothesis of whether accounting theory belongs to the natural sciences. To support this hypothesis, three characteristics of natural sciences are examined in relation to accounting theory: the relationship with the fundamental laws of nature, the existence of constants, and the abstractness of categories that require the use of mathematics. Research approach: The study has two parts, theoretical and empirical. The theoretical analysis is the starting point to formulate a general model of capital and a model for measuring human capital that contains an economic constant. Statistical tools are used in empirical research. Findings: The basic theoretical result is that understanding the category of capital and the sources of its growth is possible by applying the first and second principles of thermo-dynamics. Consequently, the existence of a constant is revealed, and the way to create other theoretically justified models is opened. The theoretical accounting restrictions were abolished as a result of a deeper interpretation of the principle of dualism. This principle revealed that it is equivalent to the first principle of thermodynamics; it does not allow capital to arise from nothing. Moreover, it clearly indicates the abstract and potential na-ture of capital, which logically leads to the second principle of thermodynamics. Practical implications: Theoretically, the rationale for calculating depreciation amounts using the current balance method and the methods and formulas for determining fair com-pensation are already proven practical implications of understanding the nature of capital and discovering the existence of a fixed amount. The discovered constant is indispensable in the issues of capital, income and salaries. Originality: The thesis that accounting is a natural science is original, as are the models and calculations using a constant.

Structure-preserving neural networks

We develop a method to learn physical systems from data that employs feedforward neural networks and whose predictions comply with the first and second principles of thermodynamics. The method employs a minimum amount of data by enforcing the metriplectic structure of dissipative Hamiltonian systems in the form of the so-called General Equation for the Non-Equilibrium Reversible-Irreversible Coupling, GENERIC (Öttinger and Grmela (1997) [36]). The method does not need to enforce any kind of balance equation, and thus no previous knowledge on the nature of the system is needed. Conservation of energy and dissipation of entropy in the prediction of previously unseen situations arise as a natural by-product of the structure of the method.Examples of the performance of the method are shown that comprise conservative as well as dissipative systems, discrete as well as continuous ones.

About Dissipative and Pseudo Port-Hamiltonian Formulations of Irreversible Newtonian Compressible Flows

In this paper we consider the physical-based modeling of 3D and 2D Newtonian fluids including thermal effects in order to cope with the first and second principles of thermodynamics. To describe the energy fluxes of non-isentropic fluids we propose a pseudo port-Hamiltonian formulation, which includes the rate of irreversible entropy creation by heat flux. For isentropic fluids, the conversion of kinetic energy into heat by viscous friction is considered as an energy dissipation associated with the rotation and compression of the fluid. Then, a dissipative port-Hamiltonian formulation is derived for this class of fluids. In the 2D case we modify the vorticity operators in order to preserve the structure of the proposed models. Moreover, we show that a description for inviscid or irrotational fluids can be derived from the proposed models under the corresponding assumptions leading to a pseudo or dissipative port-Hamiltonian structures.

El Freud cognitivo: Los conceptos de la Física en El Proyecto

espanolEl Proyecto de Psicologia para Neurologos constituye el mas energico intento de Freud de formular un modelo de funcionamiento psiquico en el marco de las Ciencias Naturales. Asi, estudia la composicion del sistema mental llegando a diferenciar la existencia de tres subsistemas neuronales y analiza los avatares de la cantidad Q, esencia de la dinamica psiquica y fundamento de la organizacion Yoica. El proposito de este trabajo es explicitar el uso de los conceptos provenientes de la Fisica de su epoca y la forma que tomaron en el Proyecto. Se presentan cuatro ejes: (1) La nocion de sistema, estado y cambio de estado, para analizar las proposiciones metateoricas. (2) La sustentacion de la dinamica psiquica en el primer y segundo principio de la Termodinamica. (3) El simil de las nociones electrodinamicas en el funcionamiento del aparato psiquico. (4) El estudio de las caracteristicas ondulatorias como sustento del tercer subsistema neuronal del modelo. EnglishThe Project for a Scientific Psychology is Freud's most forceful attempt to formulate a model of psychic functioning within the framework of the natural sciences. In order to do this he defines the psychism as a system constituted by specifiable material particles, the neurons, particles subject to changes ofstate according to an operator of change of state conceived as an amount (Q) and on which the laws of Newton validly operate. In this way, he studies the composition of the mental system, differentiating the existence of three neuronal subsystems (Fi, Psi and Omega) and analyzing the avatars of the quantity Q as a state change operator, which is essentially the motor of the Psychic dynamics and foundation of the Ego organization organization, taking this organization as a particular state of the distribution of Q in the system. The purpose of this work is to make explicit the use of the concepts coming from the physics of that time and the form they took in the Project. This paper presents four axes: 1) The notion of system, state and change of state. Freud advocates for a Psychology defined as natural science as capable of representing phenomena as quantitatively determined states of specifiable material particles. The system issubject to state changes according to a physical and measurable change ofstate operator, which corresponds to the notion of quantity (Q). 2) The support of psychic dynamicsin the first and second principles of thermodynamics. The tendency described in the Project as an impulse to the discharge of the neuronal tension to zero, is heiress of a model constructed according to the first two principles of the thermodynamics. The notion of the general irreversibility of the psychic process, despite the mechanisms that retard, and even partially reverse the direction of the process, is an implicit idea on which all repetitive phenomena are based. The concept of facilitation itself involvesthe irreversibility of the process since it does not contemplate the possibility that mechanisms exist that may allow the reverse operation, except in the exceptional situation in which, for different reasons, the expected spontaneous sense is reversed, generating the process of regression. 3) The analogy of electrodynamics notions in the functioning of the psychic apparatus. Neurons, as conductors charged by a current flowing in a given direction, are also capable of storing a quantity of excitation, cathexis, neologism derived from the word cathode, used in physics. The idea of gradual local differences in potential is the only possible justification within the model for explaining psychic work as a product of the interrelationship between energy and work. Thus, it is difficult to say that when Freud developed his project he was not thinking of an electrodynamics model, it is difficult to imagine that he did not think of current (electron flow) when he spoke of current, or that he did not think of physical resistances when he spoke of resistances, or that he did not think about tension when he described the storage of potential excitation, or else that he did not seek, finally, to formulate an Ohm law of neural function, when he spoke of their relations. 4) The study of the wave characteristics as the basis of the third neuronal subsystem of the model. The Project solves the problem of the quality by assigning to the currents in flow another property, the periodicity, independent of the quantity. This periodicity refers to frequency and frequency changes, which only in the Omega system become significant, because in the Psisystem they do not exist, neither in Fi. These are, in Freud's words, monotonous, that isto say of uniform and constant frequency so as to give a unique tone.

Work fluctuation theorems and free energy from kinetic theory

The formulation of the first and second principles of thermodynamics for a particle in contact with a heat bath and submitted to an external force is analyzed, by means of the Boltzmann–Lorentz kinetic equation. The possible definitions of the thermodynamic quantities are discussed in the light of the H theorem verified by the distribution of the particle. The work fluctuation relations formulated by Bochkov and Kuzovlev, and by Jarzynski, respectively, are derived from the kinetic equation. In addition, particle simulations using both the direct simulation Monte Carlo method and molecular dynamics, are used to investigate the practical accuracy of the results. Work distributions are also measured, and they turn out to be rather complex. On the other hand, they seem to depend very little, if any, on the interaction potential between the intruder and the bath.

Layered convection as the origin of Saturn’s luminosity anomaly

As they keep cooling and contracting, Solar System giant planets radiate more energy than they receive from the Sun. Applying the first and second principles of thermodynamics, one can determine their cooling rate, luminosity, and temperature at a given age. Measurements of Saturn's infrared intrinsic luminosity, however, reveal that this planet is significantly brighter than predicted for its age. This excess luminosity is usually attributed to the immiscibility of helium in the hydrogen-rich envelope, leading to "rains" of helium-rich droplets. Existing evolution calculations, however, suggest that the energy released by this sedimentation process may not be sufficient to resolve the puzzle. Here, we demonstrate using planetary evolution models that the presence of layered convection in Saturn's interior, generated, like in some parts of Earth oceans, by the presence of a compositional gradient, significantly reduces its cooling. It can explain the planet's present luminosity for a wide range of configurations without invoking any additional source of energy. This suggests a revision of the conventional homogeneous adiabatic interior paradigm for giant planets, and questions our ability to assess their heavy element content. This reinforces the possibility for layered convection to help explaining the anomalously large observed radii of extrasolar giant planets.

Energy and exergy analysis of solar drying process of Mint

Abstract Renewable energy in food industry and particularly in drying process is growing and mainly in developing countries. Solar energy is often used by direct products exposure through a glass or to heat drying air through a solar collector. However, the random and intermittent nature of solar radiation leads to use conventional energy sources as supplement. Hence, optimization and design tend to reduce the drying time of products for minimum possible energy use. These cases are often preceded by rigorous energy and exergy drying process analysis. That is the aim of our work in this paper. The used dryer is an indirect type, passive, without extra energy and discontinuously operating. It is composed of a solar air heater and a drying room. The experiment took place at Bouzareah on the heights of Algiers in the summer season. The choice of mint is because its abundance and its wide use in Algeria. Using the first and second principles of thermodynamics, we could estimate useful energy received by the heater and that really used during drying. Energy analysis has allowed us to quantify the solar energy received by solar heater and available for drying. Exergy analysis has allowed us to estimate the energy losses during the drying process.

Heat Exchanges in Fast, High-Performance Liquid Chromatography. A Complete Thermodynamic Study

The successive physical transformations of the mobile phase that take place in very high pressure liquid chromatography were studied based on the formalism of classical thermodynamics. The eluent is initially under atmospheric pressure ( P (0)) and at ambient temperature ( T ext). In a first step, it is compressed to a high pressure ( P max of the order of 1 kbar) in the pump heads of the chromatograph. In a second step, the pressurized eluent is transferred to the inlet of the chromatographic column, along which, in a third step, it is decompressed to atmospheric pressure. Both the compression and the decompression of the fluid were considered to take place under conditions that can be either adiabatic or nonadiabatic and either reversible or irreversible. Applications of the first and second principles of thermodynamics allow the determination of the heat and energy exchanged between the eluent and the external surroundings during each transformation. Experimental data were acquired using acetonitrile as the mobile phase. The true state equation, rho( P, T), of liquid acetonitrile was used in the theoretical calculations. A series of four different flow rates (0.55, 0.85, 1.15, and 1.45 mL/min, corresponding to inlet pressures of 357.2, 559.5, 765.1, and 972.9 bar, respectively), were applied to a 2.1 x 100 mm column packed with 1.7-mum bridged ethane-silicon hybrid particles. Thermocouples were used to measure the eluent temperature before and after its passage through the column. These data provide estimates of the variation of the internal energy of the eluent. The heat lost through the external wall of the column during the eluent decompression was estimated by measuring the surface temperature of the column tube under steady state. Both the compression and the decompression of acetonitrile were found to be nonadiabatic and irreversible transformations. The results showed that, during the eluent decompression, the heat released by the friction forces serves four different purposes: (1) it increases the eluent entropy at constant temperature (for approximately 35%); (2) it increases the temperature of the eluent (for approximately 5%); (3) it provides heat to the laboratory atmosphere (for approximately 5%); and (4) it provides some work inside the column (for approximately 5%). This quantitative heat balance description accounts well for the actual performance of the new, very high pressure liquid chromatographic technique.

Net Exchange Reformulation of Radiative Transfer in the CO2 15-μm Band on Mars

AbstractThe net exchange formulation (NEF) is an alternative to the usual radiative transfer formulation. It was proposed by two authors in 1967, but until now, this formulation has been used only in a very few cases for atmospheric studies. The aim of this paper is to present the NEF and its main advantages and to illustrate them in the case of planet Mars.In the NEF, the radiative fluxes are no longer considered. The basic variables are the net exchange rates between each pair of atmospheric layers i, j. NEF offers a meaningful matrix representation of radiative exchanges, allows qualification of the dominant contributions to the local heating rates, and provides a general framework to develop approximations satisfying reciprocity of radiative transfer as well as the first and second principles of thermodynamics. This may be very useful to develop fast radiative codes for GCMs.A radiative code developed along those lines is presented for a GCM of Mars. It is shown that computing the most important optical exchange factors at each time step and the other exchange factors only a few times a day strongly reduces the computation time without any significant precision lost. With this solution, the computation time increases proportionally to the number N of the vertical layers and no longer proportionally to its square N 2. Some specific points, such as numerical instabilities that may appear in the high atmosphere and errors that may be introduced if inappropriate treatments are performed when reflection at the surface occurs, are also investigated.

A model for crystal plasticity based on micro-slip descriptors

Within the framework of multi-field theories of damage mechanics we address the problem of crystal plasticity without introducing either the usual decomposition of the deformation gradient into elastic and plastic parts, or the associated concept of intermediate (or lattice) configuration. In comparison with the standard presentations of crystal plasticity we use a more refined kinematical description able to assess the effects of any dislocation on the macro-motion of the body. We ap ply the principle of virtual working to obtain the balance equations; the first and the second principles of thermodynamics to get suitable restrictions for the constitutive relations. A numerical simulation is worked out to illustrate the main features of the model.

Avaliação exergética de processos psicrométricos

Este trabalho teve como objetivo principal a aplicação da metodologia de avaliação dos processos psicrométricos utilizando os conceitos definidos pela combinação das 1ª e 2ª Leis da Termodinâmica, num sistema adaptado para a geração dos processos psicrométricos. Com equipamentos e instrumental adequados variaram-se, basicamente, em cada processo gerado pelo Sistema Gerador de Processos Psicrométricos (SIGEP), as vazões e as potências elétricas requeridas pelos diferentes sistemas de condicionamento do ar e as temperaturas de bulbo seco e de bulbo úmido de pontos estratégicos, dentro e fora do volume de controle, a fim de se efetuar as análises energéticas e exergética. Pode-se concluir que a metodologia de avaliação pela 1ª e 2ª Lei da Termodinâmica aplicada em processos psicrométricos é tecnicamente viável. Comprovou-se, ainda, através dos resultados obtidos, que a avaliação baseada exclusivamente na 1ª Lei da Termodinâmica (avaliação energética), em quase a totalidade dos processos gerados pelo SIGEP, é menos abrangente que a avaliação exergética. Pode-se concluir, também, que os equipamentos, acoplados ao SIGEP apresentaram um alto índice de irreversibilidade devido ao fato de terem sido dimensionados, exclusivamente, com a finalidade de atingir uma condição psicrométrica específica e não, de serem eficientes, do ponto de vista termodinâmico.

ІНТЕРАКТИВНІ ОСВІТНІ ТЕХНОЛОГІЇ В КУРСІ «МОЛЕКУЛЯРНА ФІЗИКА»

Викладання загальних і спеціальних дисциплін на фізичному факультеті неможливе без демонстраційного експерименту, але не завжди матеріальна база лабораторії відповідає сучасному рівню технічного оснащення. Використання застарілого обладнання знижує інтерес до предмету, оскільки студенти не бачать можливості застосування отриманих навичок роботи з приладами в їх подальшій виробничій діяльності. Виходом з такої проблемної ситуації може служити використання інтерактивних освітніх моделей. У зв'язку з цим авторами розроблені інтерактивні комп'ютерні моделі у вигляді окремих програмних модулів, які призначені для демонстрації теплових процесів в системах із змінним числом частинок під час вивчення першого і другого законів термодинаміки в курсі «Молекулярна фізика».