First Principle Of Thermodynamics Research Articles

Assessment of heat and entropy balance of an OWC wave energy converter

This paper deals with the thermodynamic processes governing an Oscillating Water Column (OWC) device, focusing on the entropy variation and the energy and heat budgets over the expansion–compression cycles. The influence of the thermodynamic performance on the Levelized Cost of Energy (LCOE) and the carbon footprint is analysed. The research deals with an experimental research on a simple OWC off-shore model for the purpose, with the open gas system inside the chamber formulated by a real gas model, and conceptually represented by an equivalent closed one in order to apply the First Principle of Thermodynamics appropriately. Analysed results show that the compression process is an active process, while the expansion process is a passive one. In addition, the observed non-adiabatic performance of the complete cycle implies a efficiency reduction, with consequences on the LCOE. Furthermore, an approach to emergy (embodied energy) analysis is considered, providing with concluding remarks on OWC renewability and possible impacts on the biosphere and GHG emissions. An utter approach on OWC energy and emergy assessment will be develop on future researches.

Mass and Energy Balance of a Three-Body Tribosystem

In the context of sustainable development and under the impulse of continuous technological progress, tribology contributes to the improvement of the life span of parts in dynamic contact and to the efficiency of mechanical systems. However, even if successes are obtained in lubrication, the tribology community struggles to build generalised laws of friction and wear in the case of dry friction. Based on the thermodynamics of open systems, we suggest an adaptation of the conservation of mass and energy equations to the tribosystem. The latter is modelled using the concepts of tribological triplet, tribological circuit and accommodation mechanisms. The tribosystem is described with four control volumes: two of them represent the first two bodies in dynamic contact; a third one is the tribofilm produced by the debris emission from the first bodies; a fourth control volume is used as an interface between the third body and the external environment. A mass balance is applied to these four control volumes by considering their interactions. An energy balance is then derived by applying the first principle of thermodynamics. Two systems of interdependent equations that describe the circulation of matter and energy flows in the tribosystem are outlined. These equations can be considered as a basis for future experimental developments that would aim at simultaneously characterising the different modes of energy dissipation in dynamic contact, qualitatively and especially quantitatively.

A variational formulation of thermomechanical constitutive update for hyperbolic conservation laws

In this paper, a variational framework is proposed for the constitutive update of thermomechanical constitutive models in the special case where their input results from quantities directly updated by hyperbolic conservation laws. Both a continuum and a consistent first order accurate discrete settings are derived. The originality of this work lies in that the constitutive update is driven by the rates of some strain measure and the internal energy density in the continuum setting, leading to a rate-type description of the local constitutive problem, and by the updated values at some discrete time of these strain measure and internal energy density in the discrete setting. These quantities are updated by the solution of a system of discrete conservation laws including the first principle of thermodynamics, ensuring that the right shock speeds will be computed. This point is of crucial importance when simulating impact on structures for instance. The proposed variational approach is illustrated for thermo-hyperelastic-viscoplastic solid media, especially using the parameterization of the flow rule direction based on pseudo-stresses proposed by Mosler & co-workers. The proposed discrete variational solver is then coupled with the second order accurate flux difference splitting finite volume method, which permits to solve the set of conservation laws. Comparisons are performed on a set of test cases with numerical solutions obtained with finite elements coupled to an explicit time-stepping and to a temperature-driven variational constitutive update. They allow to show the good behavior of the proposed approach.

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.

Research on the combustion process in the Fiat 1.3 Multijet engine fueled with rapeseed methyl esters

Abstract The aim of the paper is to analyze and evaluate the basic parameters of the combustion process in a modern Fiat 1.3 Multijet diesel engine, fuelled esters (FAME) and diesel oil. During the tests on an engine test bed, the pressure waveforms in the cylinder were measured, on the basis of which the averaged actual indicator graphs were established in the determined engine operating conditions. On their basis, the pressure increase rates were determined and heat release characteristics were prepared based on the equation of the first principle of thermodynamics. The characteristics of the relative amount of heat released and the characteristics of the relative heat release rate were determined. The use of rapeseed methyl esters to supply the engine had an impact on the parameters of the combustion process as compared to its supply with diesel oil. Differences in the waveforms of heat release characteristics of the engine powered by the tested fuels are significantly greater at low loads. At the lowest engine loads, esters burn much faster than diesel oil. With the increase in engine load, the differences in the waveform of heat release characteristics during combustion of these fuels were significantly smaller.

Experimental and numerical investigations on rolling element bearing thermal behaviour

In the present study, some measurements have been conducted on a dedicated test rig to investigate rolling element bearing thermal behaviour. This test rig makes possible the determination of the tested rolling element bearing power losses through the resistive torque measurement. Some thermocouples are located on fixed parts of the system (housing, rolling element bearing outer ring) and others on rotating parts (rolling element bearing inner ring and shaft) via a telemetry system. A deep groove ball bearing, whose pitch diameter is equal to 85 mm, has been tested under oil jet lubrication for different operating conditions. Measurements of the penetration ratio, defined as the proportion of oil actually entering the rolling element bearing versus the oil injected, have also been conducted. An extended thermal network of the test rig has been established to enable a closer understanding of the rolling element bearing inner thermal behaviour. Based upon the first principle of thermodynamics for transient conditions, the studied system is divided into lumped elements at uniform temperature connected by thermal resistances which account for conduction, radiation and convection. Convection within the rolling element bearing depends on the amount of oil in the oil–air mixture known as the volume fraction. At specific test conditions, the developed model found good agreements with experiences for a given oil volume fraction of 15%. This value of volume fraction leads to an adapted formula for volume fraction in the case of jet lubrication which includes the measured penetration ratio.

The first principle of thermodynamics as applied to the analysis of processes in piston engines

The discrepancy between the classical interpretation of the first law of thermodynamics and the real working process in piston ICEs is considered. A new representation of the law and its graphic interpretation are proposed. Keywords thermodynamics, first principle, internal energy, heat, work against external forces. dorokhovaf@rambler.ru

Accounting among the Natural Sciences

This paper develops research in order to clarify whether accounting theory belongs to the natural sciences. Three features characterizing these sciences are identified and evaluated. These are the relationships of accounting theory with respect to the fundamental laws of nature, the possible existence of necessary constants, and the abstractness of the categories introduced, which requires the use of mathematics. Studies have shown that these characteristics are fully visible. The second principle of thermodynamics has shown its significant influence leading to the indication of the existence of a constant quantity, necessary in capital accounts. It also turned out to be the basis of the original method of calculating the depreciation of assets. The principle of dualism, fundamental for accounting, revealed that it is, among other things, equivalent to the first principle of thermodynamics. And the principle of minimum action has always stimulated the development of cost accounting and management accounting. The practical significance of the research presented in the second part of the article consists in revealing of the economic constant. This constant determines the actions of nature in economic processes. As a result of the research, the knowledge of the possibilities of the accounting system is being expanded, in particular by incorporating the measurement of human capital of employees and opening the way to financial reporting in this area.

On the fundamental equations of unsteady anisothermal viscoelastic piezoelectromagnetism

The derivation of the piezoelectric equations requires only the Maxwell equations of electrostatics and the momentum equation with electric forces, together with the constitutive equations derived from the first principle of thermodynamics. In the non-isothermal case, the inclusion of thermal conduction requires also the second principle of thermodynamics and then the equation of energy becomes necessary. Furthermore, in the viscoelastic case, the viscous stresses modify the momentum and energy equations. The sequence outlined above provides the simplest derivation of the fundamental equation of anisothermal viscoelastic piezoelectricity including thermal and viscous dissipation. The equations of piezomagnetism are similar to those of piezoelectricity, replacing the electric by magnetic fields. The coupling of the unsteady electric and magnetic fields through electromagnetic waves interacts with both piezoelectricity and piezomagnetism leading to piezoelectromagnetism. In the general case of unsteady anisothermal piezoelectromagnetism, the energy, momentum and Maxwell equations specify the temperature, displacement vector, electric field and magnetic field. The coefficients involve constitutive and diffusion tensors specifying the properties of matter, generally anisotropic, such as crystals and orthotropic plates. They can also specify the properties of amorphous substances corresponding to the simplest isotropic case.

Advances in thermal level measurement techniques using mathematical models, statistical models and decision support systems in blast furnace

The estimation of thermal level in blast furnace is of utmost importance, because the processes occurring inside the blast furnace are complex in nature and any drift in thermal level could lead to abnormal furnace state. The present review is made to understand the methods for estimating thermal level in blast furnace, and the drift in estimation of the thermal level. The thermal level estimation is divided into 3 categories, viz. mathematical models, statistical models and decision support systems. The mathematical models are based on the first principle of thermodynamics and give an estimate of the thermal level in blast furnace. On the other hand, the statistical models are mainly the data-based approach that uses the historical data to predict the instability in blast furnace. Lastly, the decision support systems are the prescriptive models that give the recommendations for making the necessary corrections in the process parameters to avoid occurrence of abnormality in blast furnace. Further, the drifts in estimation of thermal level by these techniques are identified and recommendations are made to improve the accuracy of thermal level estimation. The recommendations to control thermal level in blast furnace are provided which when applied in the industrial blast furnace, can avoid the occurrence of catastrophic condition.

The Epistemological Foundations of Freud's Energetics Model.

This article aims to clarify the epistemological foundations of the Freudian energetics model, starting with a historical review of the 19th century scientific context in which Freud’s research lay down its roots. Beyond the physiological and anatomical references of Project for a Scientific Psychology (Freud, 1895a), the physiology Freud makes reference to is in reality primarily anchored in an epistemological model derived from physics. Whilst across the Rhine, the autonomy of physiology in relation to physics was far from being accomplished, as a counterpoint, in France, the revolution in physiology driven by Claude Bernard established itself autonomously from physics,. In contrast, Freud’s scientific landscape is entirely dominated by the physics elevated to the rank of an ideal science. The influence of Helmholtz, who is both a medical doctor and a physicist, has a determining influence on Freud’s training. The discoveries in physics at that time, in particular the formulation of the principle of ‘conservation of force’ – first principle of thermodynamics – will constitute the points of reference upon which Freud will elaborate his energetics model, then subsequently, the idea of economy in his metapsychology. In this way we can trace both the historic and epistemological path that led Freud from a concept based on physics, and more specifically thermodynamic energy, to an idea of nervous energy that constitutes the basis of the concept of “quantity” as it is stated as ‘first fundamental idea’ in Project for a Scientific Psychology (Freud, 1895a). This notion will subsequently evolve, and lead Freud to the introduction of the concept of ‘psychical energy,’ this time in a purely metapsychological sense.

Propuesta didáctica para el empleo de la Historia de la Ciencia en la enseñanza del Primer Principio de la Termodinámica en Educación Secundaria

El empleo de recursos históricos en la enseñanza de las asignaturas de Ciencias está ampliamente recomendado tanto en Educación Básica, como en Secundaria y Superior. Esto se debe a que la historia de la ciencia como recurso educativo se emplea para motivar al alumnado, además de mostrar la ciencia como actividad humana, permitiendo trabajar contenidos de naturaleza de la ciencia. Sin embargo, este recurso no es eficaz si no se emplea con un enfoque reflexivo.En este artículo se desarrolla una propuesta didáctica en la que se muestra cómo el desarrollo histórico del Primer Principio de la Termodinámica, temática propuesta en el curriculum de Educación Secundaria, puede ayudar a que el alumnado comprenda estos conceptos científicos abstractos y de gran dificultad para ellos. La historia de la ciencia es un buen recurso para provocar conflictos cognitivos que ayuden a cambiar las concepciones alternativas del alumnado por otras más cercanas a lo aceptado por la comunidad científica. Además, contribuye a conseguir que dicho alumnado desarrolle las competencias curriculares. Finalmente, a través del desarrollo histórico de conceptos científicos el alumnado podrá conocer, de manera interdisciplinar, la importancia del trabajo científico a lo largo de la historia. También potenciará la relación de esta asignatura con otras como la historia y la filosofía, fomentando así la capacidad del alumnado para reflexionar y pensar de forma crítica.

Connection between the Principles of Thermodynamics and the Conservation Laws: Physical Meaning of the Principles of Thermodynamics

It has been shown that the first principle of thermodynamics follows from the conservation laws for energy and linear momentum. And the second principle of thermodynamics follows from the first principle of thermodynamics under realization of the integrating factor (namely, temperature) and is a conservation law. The significance of the first principle of thermodynamics consists in the fact that it specifies the thermodynamic system state, which depends on interaction between conservation laws and is non-equilibrium due to a non-commutativity of conservation laws. The realization of the second principle of thermodynamics points to a transition of the thermodynamic system state into a locally-equilibrium state. Phase transitions are examples of such transitions.

Solving the temperature problem under relativistic conditions within the frame of the first principle of thermodynamics

The first principles of thermodynamics under relativistic conditions and with allowance for surface tension were formulated. Two cases were studied - for Minkowski and Euclidean spaces. With the help of these laws, the temperature of the system was shown to vary according to Ott H at the adiabatic and non-adiabatic acceleration, i.e., the temperature increases for an observer in the laboratory reference frame as the velocity of the object increases. A Einstein considered that the temperature had, on the contrary, to decrease under these conditions as the velocity increased. It was shown where he had made an error.

The First Principle of Thermodynamics under Relativistic Conditions and Temperature

The First Principle of Thermodynamics under Relativistic Conditions and Temperature

Clausius et la chaleur : le passage dissimulé de la substance à l'algèbre

Still nowadays, no one algebraic definition of heat is taught. Although anybody can easily make is own idea about heat, this non-regular lack, from the point of view of theoretical physics, can be explained by an historical consideration on the creation by Clausius of internal energy. In 1850, Clausius publishes On the Moving Force of Heat in which internal energy and entropy are created in order to make thermodynamics an entirely mathematical science. At the beginning, Clausius deny to Carnot that heat could be a conserved quantity, then, considering an ideal gas in a thermodynamical cycle, he shows that the conserved quantity cannot be heat, but another one, made by Clausius and called later "internal energy" by himself too. The main point of his demonstration is that the elementary quantity δQ cannot be an exact differential. Of course, a so important conclusion has several great consequences about thermodynamics in general. Firstly, internal energy becomes the new main quantity in thermodynamics, secondly, heat can be defined as the internal energy variation not due to mechanical work. Moreover, what is called "first principle of thermodynamics" can be seen as a simple consequence of this heat definition.

Revisiting Cent-Fonts Fluviokarst Hydrological Properties with Conservative Temperature Approximation

We assess the errors produced by considering temperature as a conservative tracer in fluviokarst studies. Heat transfer that occurs between karstic Conduit System (CS) and Porous Fractured Matrix (PFM) is the reason why one should be careful in making this assumption without caution. We consider the karstic aquifer as an Open Thermodynamic System (OTS), which boundaries are permeable to thermal energy and water. The first principle of thermodynamics allows considering the enthalpy balance between the input and output flows. Combined with a continuity equation this leads to a two-equation system involving flows and temperatures. Steady conditions are approached during the recession period or during particular phases of pumping test experiments. After a theoretical study of the error induced by the conservative assumption in karst, we have applied the method to revisit the data collected during a complete campaign of pumping test. The method, restricted to selected data allowed retrieving values of base flow, mixing of flow, intrusions of streams, and aquifer answer to drawdown. The applicability of the method has been assessed in terms of propagation of the temporal fluctuations trough the solving but also in terms of conservative assumption itself. Our results allow retrieving the main hydrological properties of the karst as observed on field (timed volumetric samplings, geochemical analyses, step pumping test and allogenic intrusion of streams). This consistency argues in favor of the applicability of the conservative temperature method to investigating fluviokarst systems under controlled conditions.

Specific Heat of Tribological Wear Debris Material

Stationary processes of solid friction, heating and wear are analyzed in this paper on the basis of the first principle of thermodynamics. Analytical dependences between physical parameters of a tribological system have been determined. Densities of extensive quantity fluxes are referred to elementary surface and elementary time, which has permitted to include intensive quantities, especially temperature, in the model presented here. Although the discussion is restricted to the phenomenological approach, conclusions regarding some microscopic properties of the matter in the process of fragmentation are drawn directly from the laws of energy and mass conservation. Differences between specific heat of the starting material cp and of the debris produced cp′ are emphasized. The model of the friction process described by Maciąg, M. (2010, “Thermodynamic Model of the Metallic Friction Process,” ASME J. Tribol., 132(3), pp. 1–7) has been modified and a new method of evaluating cp′ is proposed. Results of standard friction and wear testing are used to describe selected tribological systems in quantitative terms based on the thermodynamic model discussed here (Sadowski, J., and Żurowski, W., 1992, “Thermodynamic Aspects of Metals' Wear-Resistance,” Tribol. Lubr. Eng., 3, pp. 152–159). Very high specific heat of tribological wear debris material is found at the moment of the material's production. To conclude, results of theoretical and experimental analysis are discussed and their interpretation is proposed. Applicability of the system magnitudes C and D to modeling of friction and wear is highlighted.

What price of speed? A critical revision through constructal optimization of transport modes

The use of energy by the major modes and the environmental impact of freight transportation is a problem of increasing importance for future transportation policies. This paper aims to study the relative energy efficiency of the major transport modes, setting up an impartial analysis, improving previous literature substantially. Gabrielli and von Karman have studied the relationship between speed and energy consumption of the most common transport modes. From this pioneering activity different methods for evaluating the energetic performance of vehicles have developed. Initially the maximum vehicle power and theoretical performance limits have been calculated in terms of weight and payload. Energy efficiency has then been evaluated in terms of the first principle of thermodynamics as the mass of the vehicle times distance moved divided by thermal energy used. A more effective analysis can be performed both in terms of vehicle life cycle and in terms of second principle considering the quality and the amount of dissipated amount of useful energy. This paper defines an LCA based model, which could allow an effective comparison between different transport modes classifying them in terms of exergy destruction. In this case, an effective comparison, which considers the quality of used energy, can be performed allowing precise politics for a future more effective evaluation of the transport modes.

Dynamic Thermal Model of a Lighting System and its Thermal Influence within a Low Energy Building

This paper focuses on the heat gain of a lighting system, one of the most-used appliances in buildings, and its thermal effect within a low energy building. In this study, a dynamic thermal model of a lighting system is first established based on the first principle of thermodynamics. Then, thermal parameters of this model are estimated by experiments and an optimization process. Afterward, the obtained model of the system is validated by comparing simulation results to experimental one. Finally it is integrated into a low energy building model in order to quantify its thermal influence within a low energy building. As a result, heat flux of the lighting system, indoor temperature and heating energy demands of the building are obtained and compared with the results obtained by the conventional model of a lighting system. This paper helps to understand thermal dynamics of a lighting system and to further apply lighting systems for energy management of low energy buildings.