Traditional Thermodynamics Research Articles

Determining Planetary Temperatures with the Stefan-Boltzmann Law

What follows is a description of several activities involving the Stefan-Boltzmann radiation law that can provide laboratory experience beyond what is normally found in traditional introductory thermodynamics experiments on thermal expansion, specific heat, and heats of transformation. The activities also provide more extensive coverage of and hands-on experience with the radiation law than is normally found in a traditional thermodynamics curriculum.

Estimation of critical grain size at different temperatures and thermodynamic stability of γ→α in NC Fe by QDA and EOS methods

Thermodynamic properties of Nanocrystalline (NC) materials are essentially different from the conventional coarse-grained materials (with the same chemical composition). The role of grain boundary is very important in the characterization of thermodynamic functions and thermal properties of NC materials when the grain size is less than 100 nm. Therefore, the traditional thermodynamics being applied for coarse-grained materials is not applicable for NC materials. In this study, Quasiharmonic Debye Approximation (QDA) and Equation of State (EOS) methods are used to calculate the Gibbs free energy in NC Fe. Since the Gibbs free energy for Fe, predicted by EOS and QDA methods, is inaccurate (especially at temperatures higher than the ambient temperature), a term called as Δ G Excess is proposed to modify the results. Thus, the Modified QDA (MQDA) and Modified EOS (MEOS) methods are introduced for this purpose. Thereafter, the change in the Gibbs free energy for γ-Fe to α-Fe phase transformation (Δ G γ→α ) via the grain size is calculated by MQDA and MEOS methods. The results obtained by the two methods are also compared and discussed. Finally, the critical grain size, at which Δ G γ→α =0, can be estimated at different temperatures, is found to increase with increasing temperature.

Temperature‐Dependent Prediction of the Liquid Entropy of Ionic Liquids

Modeling of the temperature-dependent liquid entropy of ionic liquids (ILs) with great accuracy using COSMO-RS is demonstrated. The minimum structures of eight IL ion pairs are investigated and the entropy, calculated from ion pairs, is found to differ on average only 2% from the available experimental values (119 data points). For calculations with single ions, the average error amounts to 2.6% and stronger-coordinating ions tend to give higher deviations. Additionally, the first parameterization of the standard liquid entropy for ILs is presented in the context of traditional volume-based thermodynamics (S(l)(0)=1.585 kJ mol(-1) K(-1) nm(-3)·r(m)(3)+14.09 J mol(-1) K(-1)), which sheds light on the statistical treatment of ionic interactions. The findings provide the first direct access to accurate predictions of liquid entropies of ILs, which are tedious and time-consuming to measure.

Thermodynamics of substances with negative thermal expansion and negative compressibility

Abstract It is shown that for substances with positive thermal expansion and positive compressibility, and for substances with negative thermal expansion and negative compressibility, δQ = d U + P d V , but for substances with positive thermal expansion and negative compressibility, and for substances with negative thermal expansion and positive compressibility, δQ = d U − P d V . The result obtained helps to calculate processes which do not obey traditional thermodynamics.

The Reynolds transport theorem: Application to ecological compartment modeling and case study of ecosystem energetics

The Reynolds transport theorem (RTT) from mathematics and engineering has a rich history of success in mass transport dynamics and traditional thermodynamics. This paper introduces RTT as a complementary approach to traditional compartmental methods used in ecological modeling and network analysis. A universal system equation for a generic flow quantity is developed into a generic open-system differential expression for conservation of energy. Nonadiabatic systems are defined and incorporated into control volume (CV) and control surface (CS) perspectives of RTT where reductive assumptions in empirical data are then formally introduced, reviewed, and appropriately implemented. Compartment models are abstract, time-dependent systems of simultaneous differential equations describing storage and flow of conservative quantities between interconnected entities (the compartments). As such, they represent a set of flexible and somewhat informal, assumptions, definitions, algebraic manipulations, and graphical depictions subject to influence and selectively parsed expression by the modeler. In comparison, RTT compartment models are more rigorous and formal integro-differential equations and graphics initiated by the RTT universal system equation, forcing an ordered identification of simplifying assumptions, ending with clearly identified depictions of the transfer and transport of conservative substances in physical space and time. They are less abstract in the rigor of their equation development leaving less ambiguity to modeler discretion. They achieve greater consistency with other RTT compartment style models while possibly generating greater conformity with physical reality. Characteristics of the RTT approach are compared with those of a traditional compartment model of energy flow in an intertidal oyster-reef community.

Endoreversible thermodynamics approach for optimum oven operation

This paper refers to the problem of how much heat is necessary for oven operation. An endoreversible thermodynamics approach is used here. More accurate upper bounds for the oven heat gain factor are obtained than when the traditional reversible thermodynamics approach is used. The optimum operation temperatures and the oven heat gain factor depend on three parameters incorporating both design and thermal factors. The quantities associated with reversible operations are recovered in the limiting case of infinitely large conductance. In the more realistic case of finite sizes one shows that the equipartition principle acts for the conductances of the heat engines and heat pumps driving the endoreversible oven, but does not act at the level of the system. The results show that reducing the present day fuel consumption by an order of magnitude for oven operation is, in principle, possible.

Performance of a Novel Semiclosed Gas-Turbine Refrigeration Combined Cycle

A thermodynamic performance analysis was performed on a novel cooling and power cycle that combines a semiclosed gas turbine called the high-pressure regenerative turbine engine (HPRTE) with an absorption refrigeration unit. Waste heat from the recirculated combustion gas of the HPRTE is used to power the absorption refrigeration cycle, which cools the high-pressure compressor inlet of the HPRTE to below ambient conditions and also produces excess refrigeration depending on ambient conditions. Two cases were considered: a small engine with a nominal power output of 100kW and a large engine with a nominal power output of 40MW. The cycle was modeled using traditional one-dimensional steady-state thermodynamics, with state-of-the-art polytropic efficiencies and pressure drops for the turbomachinery and heat exchangers, and curve fits for properties of the LiBr-water mixture and the combustion products. The small engine was shown to operate with a thermal efficiency approaching 43% while producing 50% as much 5°C refrigeration as its nominal power output (roughly 50tons) at 30°C ambient conditions. The large engine was shown to operate with a thermal efficiency approaching 62% while producing 25% as much 5°C refrigeration as its nominal power output (roughly 20,000tons) at 30°C ambient conditions. Thermal efficiency stayed relatively constant with respect to ambient temperature for both the large and small engines. It decreased by only 3–4% as the ambient temperature was increased from 10°Cto35°C in each case. The amount of external refrigeration produced by the engine sharply decreased in both engines at around 35°C, eventually reaching zero at roughly 45°C in each case for 5°C refrigeration. However, the evaporator temperature could be raised to 10°C (or higher) to produce external refrigeration in ambient temperatures as high as 50°C.

Phenomenological approach to the caloric theory of heat

This contribution presents an alternative approach to thermal physics and to its affiliated thermodynamics aiming to initiate a discussion concerning the related problems of its fundamental nature. We reason that the classical thermodynamics suffers considerably from a misinterpretation of experimental facts known as the Principle of Equivalence of Energy and Heat and from the resulting introduction of a troublesome quantity called entropy lacking clear physical meaning within the traditional thermodynamics. As this concept generates an endless chain of paradoxes connected mainly with the Second Law of Thermodynamics, we propose to change the structure and the conceptual basis of thermal physics prior to the solving of more complex problems involving, e.g., the application of quantum or stochastic electrodynamics to the relativistic thermal phenomena. We argue that a good candidate for such a more satisfactory theory is modified Carnot's theory reintroducing an old–new physical quantity historically named caloric. An introducing outline customizing the reader with the basic ideas of this alternative version of the classical thermodynamics is thus given. Principal relations of the caloric theory are presented, together with illustrative treatment of some common tasks of the thermal physics. Use of the caloric theory to description of real heat engines is also presented.

Observable Quantities for Electrodiffusion Processes in Membranes

Electrically driven ion transport processes in a membrane system are analyzed in terms of observable quantities, such as the apparent volume flow, the time dependence of the electrolyte concentration in one cell compartment, and the electrical potential difference between the electrodes. The relations between the fluxes and these observable quantities are rigorously deduced from balances for constituent mass and solution volume. These relations improve the results for the transport coefficients up to 25% with respect to those obtained using simplified expressions common in the literature. Given the practical importance of ionic transport numbers and the solvent transference number in the phenomenological description of electrically driven processes, the transport equations are presented using the electrolyte concentration difference and the electric current as the drivers of the different constituents. Because various electric potential differences can be used in this traditional irreversible thermodynamics approach, the advantages of the formulation of the transport equations in terms of concentration difference and electric current are emphasized.

Kinetic theory of nucleation based on a first passage time analysis: Improvement by the density-functional theory

A recent kinetic theory of nucleation [see, e.g., E. Ruckenstein and B. Nowakowski, J. Colloid Interface Sci. 137, 583 (1990)] is based on molecular interactions and avoids the traditional thermodynamics. The rate of emission of molecules from a cluster is found via a first passage time analysis. This time is calculated by solving the single-molecule master equation for the probability distribution function of a surface molecule located in the potential field created by the cluster. The liquid cluster was assumed to have sharp boundaries and uniform density. In the present paper, this assumption is removed by using the density-functional theory to find the density profiles. Thus, more accurate calculations of the potential field created by the cluster, its emission rate, and nucleation rate are obtained. The modified theory is illustrated by numerical calculations for a molecular pair interaction potential combining the dispersive attraction with the hard-sphere repulsion.

Deriving amino acid contact potentials from their frequencies of occurrence in proteins: alattice model study

The possibility of deriving the contact potentials between amino acids from theirfrequencies of occurrence in proteins is discussed in evolutionary terms. This approachallows the use of traditional thermodynamics to describe such frequencies and,consequently, to develop a strategy to include in the calculations correlations due to thespatial proximity of the amino acids and to their overall tendency of being conserved inproteins. Making use of a lattice model to describe protein chains and defining a ‘true’potential, we test these strategies by selecting a database of folding model sequences,deriving the contact potentials from such sequences and comparing them with the ‘true’potential. Taking into account correlations allows for a markedly better prediction of theinteraction potentials.

Computer-Based Thermodynamics

A new computer-based approach to teaching thermodynamics is being developed and tried by two mechanical engineering professors at the U.S. Naval Academy. The course uses sophisticated software, in this case CyclePad, to work all of the homework problems. A new text, written with traditional theory but computer-based problems, accommodates the new approach. The new course is scheduled for Fall Term 2001 at the Naval Academy. Computer-based thermodynamics courses teach the same theory as traditional thermodynamics courses as well as the same types of problems. However, traditional thermodynamic cycle hand calculations are replaced by cycle calculations using CyclePad. This new example of Intelligent Computer-Assisted Instruction, ICAI, switches emphasis from learning cycle calculations to learning cause and effect through parametric analysis. Parametric analysis is made feasible through experimentation using computer models. For this, CyclePad has artificial intelligence, sensitivity analysis and graphical presentation capabilities. Traditionally, thermodynamics culminates in analysis of the thermodynamic cycles. In this course, students will progress well beyond traditional thermodynamics courses by emphasizing cycle analysis.

Modern thermodynamics in CVD of hard materials

The diamond growth together with the graphite etching under low pressure had often been regarded as a “thermodynamic paradox” maybe “violating the second law of thermodynamics”, since the success of the activated chemical vapor deposited (CVD) diamond processes in 1970. After quantitative verification of reaction coupling, a series of nonequilibrium phase diagrams for the activated diamond processes have been quantitatively calculated. These nonequilibrium phase diagrams agree excellently with experiments. However, there is no room for the nonequilibrium phase diagram in both classical equilibrium thermodynamics and traditional nonequilibrium thermodynamics. Therefore, the systematization of modern thermodynamics has been drastically changed and a new field for nonequilibrium phase diagrams emerges. Nonequilibrium phase diagrams for activated CVD cubic boron nitride processes have also been calculated in this paper.

Statistical thermodynamics of hindered rotation from computer simulations

Due to the nonlinearity of internal molecular coordinate space, comprehensive statistical mechanical treatment of polyatomic molecules presents a formidable theoretical problem where traditional statistics does not hold. Here we introduce a new theoretical approach to the hindered internal rotor problem, which relies on simulated statistics of microstates, rather than on first-principles calculations of the partition function. The concept links traditional statistical-mechanical thermodynamics to an authentic treatment of curvilinear descriptive statistics. The results are illustrated by classical molecular dynamics simulations.

Templated Organic Synthesis. Edited by F. Diederich (diederich@org.chem.ethz.ch) and Peter J. Stang (stang@chemistry.chem.utah.edu). Wiley-VCH: Weinheim. 1999. XX+411 pp. 268 DM. ISBN 3-527-29666-2

Physicochemical theoretical development has been dwarfed by the abundant experimental achievements in molecular recognition studies, including the template effects reported in this book [1-3].[...]

Modern Thermodynamics: From Heat Engines to Dissipative Structures.

first_page settings Order Article Reprints Font Type: Arial Georgia Verdana Font Size: Aa Aa Aa Line Spacing:    Column Width:    Background: Open AccessBook Review Modern Thermodynamics: From Heat Engines to Dissipative Structures. by Shu-Kun Lin Molecular Diversity Preservation International (MDPI), Kandererstrasse 25, CH-4057 Basel, Switzerland Entropy 1999, 1(4), 148-149; https://doi.org/10.3390/e1040148 Received: 7 September 1999 / Published: 1 December 1999 Download Download PDF Download PDF with Cover Download XML Download Epub Versions Notes For readers interested in the Prigogine school of thermodynamics, this book is the first choice because it is a textbook. Conventionally textbooks are places where only mature theories are described and carefully presented [1]. The other important source is Prigogine's Nobel lecture [2]. The representative original literature is listed in this book, particularly on page 455. This book is in contrast to other thermodynamic textbooks regarding time. Many other authors of thermodynamic texts insist that thermodynamics is independent of time. However, here time and the "arrow of time" have been mentioned frequently and time t appears in mathematical expressions throughout this thermodynamics textbook, even in the first chapters where traditional thermodynamics is otherwise well presented. In order to avoid confusion for students, the reviewer (Lin) believes that time-dependent phenomena and theories should be discussed elsewhere in the context of chemical kinetics, and fluid dynamics, etc., not in thermodynamics [3]. Traditionally thermodynamics also discusses the open system and nonequilibrium. Prigogine has introduced a dissipative structure concept and mathematical equations for entropy S and time t for the open system and nonequilibrium. These are presented in chapters 12-18. The dissipative structure is defined as being really far from the equilibrium case. However, the higher-order terms in the Taylor series of entropy expression of fluctuation cannot be neglected if the considered system is really far from equilibrium (Chapter 18). Readers must duly have expected the earnest application of this entropy theory in the final two chapters. However, only many familiar equations of chemical kinetics have been applied. Amazingly the symbol of entropy S did not appear once in any of the many equations in Chapter 19, Dissipative Structures. AcknowledgmentsI am very grateful to Dr. Dilip Kondepudi ([email protected], Wake Forest University) and Dr. Andrew Slade ([email protected], Wiley) for their kind assistance.References and NotesSeveral books co-authored by Prigogine were published recently. For example, Stengers, I.; Prigogine, I. The End of Certainty: Time, Chaos, and the New Laws of Nature; Free Press: New York, 1997. [Google Scholar] Prigogine, I. Time, structure, and fluctuations. Science 1978, 201, 777–785. [Google Scholar] [CrossRef] [PubMed]Lin, S.-K. Editorial: diversity and entropy. Entropy 1999, 1, 1–3. ( http://wwwmdpiorg/entropy/htm/e1010001htm). [Google Scholar] [CrossRef] © 1999 by MDPI (http://www.mdpi.org). Reproduction is permitted for noncommercial purposes. Share and Cite MDPI and ACS Style Lin, S.-K. Modern Thermodynamics: From Heat Engines to Dissipative Structures. Entropy 1999, 1, 148-149. https://doi.org/10.3390/e1040148 AMA Style Lin S-K. Modern Thermodynamics: From Heat Engines to Dissipative Structures. Entropy. 1999; 1(4):148-149. https://doi.org/10.3390/e1040148 Chicago/Turabian Style Lin, Shu-Kun. 1999. "Modern Thermodynamics: From Heat Engines to Dissipative Structures." Entropy 1, no. 4: 148-149. https://doi.org/10.3390/e1040148 Find Other Styles Article Metrics No No Article Access Statistics For more information on the journal statistics, click here. Multiple requests from the same IP address are counted as one view.

Introduction to the theory of forced equilibria: General principles, basic concepts, and definitions

Until now, only a small amount of work has been done to verify the constraints of using fundamental regularities of the exact sciences in geochemistry and mineralogy. As for the chemical thermodynamics, the most important problem is the inadequate presentation of the thermodynamic state of real mineral systems. Our contention is that this state cannot be rigorously referred to any conventional type, if examined by the traditional chemical thermodynamics, and must be analyzed in terms of forced-equilibrium theory. The forced equilibrium is defined as a specific thermodynamic state resulting from the action of forcing factors, that is, the conditions or constraints which restrict possible variations of principal or internal thermodynamic system parameters. The advantage of this approach is that it proceeds from the operative forcing factor to the actual type of equilibrium of the real system, whereas the traditional analysis usually postulates the type of equilibrium state without proof of adequacy. The equilibrium conditions for thermoelastic solids with a coherent interphase boundary are a good example of forced equilibrium. The numerical modelling of forced equilibria in some real mineral systems and the comparison of the results with experimental and natural data show that the actual thermodynamic states of mineral systems more often represent stable or metastable forced equilibria than kinetically depressed or metastable states in their traditional understanding.

Application of Continuous Thermodynamics to The Stability of Polymer Systems. IV

Abstract A method for establishing in the framework of continuous thermodynamics the stability criteria for multiple critical states of increasing order is presented. The method applies to a relatively general class of Gibbs free energy relations for polymer solutions: The function replacing the χ-term in the classic Flory-Huggins theory is permitted to depend on a finite number of moments of the polymer distribution so as to embrace most Gibbs free energy relations used in practice. In this way, determinant criteria for multiple critical states are formulated that are analogous in structure to those in traditional (discrete) thermodynamics. However, the dimension of the determinants is reduced from N (number of polymer species) to n (number of moments taken into account).

QUAS1-THERMODYNAMIC MODEL OF THE DISSIPATIVE SYSTEMS AND ITS APPLICATION TO PHASE TRANSITIONS IN OPTICAL BISTABILITY

Taking the optical system as a prototype, this paper demonstrates that a quasi-thermodynamic model for dissipative systems, satisfying the principle of detailed balance, may be developed, which is parallel to the traditional thermodynamics. The present systems are described by the generalized dynamical equation of nonlinear optical cavities, introduced in previous work of Ou Fa et al. In view of the quasi-thermodynamic model, the critical phenomena and phase transitions in optical bistability are discussed systematically and generally. By taking the advantage of Ginzburg-Landau's model, the fluctuations and correlations near the (second kind of) critical point of optical bistability are studied also. So the Landau's theory of phase transitions in equilibrium thermodynamics is generalized to the bistable dissipative systems far from equilibrium.

Chemical potential and temperature of light

Light is treated as heat in traditional thermodynamics. Photons are assigned a temperature but zero chemical potential. In processes such as photovoltaic or photochemical absorption, electroluminescence and chemiluminescence, the number of photons is related to that of other energy quanta, e.g. electron—hole pairs or chemical excitations. This leads to a non-zero chemical potential of photons allowing the treatment of these processes by analogy with ordinary chemistry: equilibrium is reached when the sum of the chemical potentials, including that of photons, is zero.