International Nuclear Information System (INIS)
Roh, Heui-Seol
2015-01-01
Chemical energy transfer mechanisms at finite temperature are explored by a chemical energy transfer theory which is capable of investigating various chemical mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium. Gibbs energy fluxes are obtained as a function of chemical potential, time, and displacement. Diffusion, convection, internal convection, and internal equilibrium chemical energy fluxes are demonstrated. The theory reveals that there are chemical energy flux gaps and broken discrete symmetries at the activation chemical potential, time, and displacement. The statistical, thermodynamic theory is the unification of diffusion and internal convection chemical reactions which reduces to the non-equilibrium generalization beyond the quasi-equilibrium theories of migration and diffusion processes. The relationship between kinetic theories of chemical and electrochemical reactions is also explored. The theory is applied to explore non-equilibrium chemical reactions as an illustration. Three variable separation constants indicate particle number constants and play key roles in describing the distinct chemical reaction mechanisms. The kinetics of chemical energy transfer accounts for the four control mechanisms of chemical reactions such as activation, concentration, transition, and film chemical reactions. - Highlights: • Chemical energy transfer theory is proposed for non-, quasi-, and equilibrium. • Gibbs energy fluxes are expressed by chemical potential, time, and displacement. • Relationship between chemical and electrochemical reactions is discussed. • Theory is applied to explore nonequilibrium energy transfer in chemical reactions. • Kinetics of non-equilibrium chemical reactions shows the four control mechanisms
de Oliveira, Mário J
2017-01-01
This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This new edit...
Local thermodynamic equilibrium in rapidly heated high energy density plasmas
International Nuclear Information System (INIS)
Aslanyan, V.; Tallents, G. J.
2014-01-01
Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance
The energy balance of a plasma in partial local thermodynamic equilibrium
Kroesen, G.M.W.; Schram, D.C.; Timmermans, C.J.; de Haas, J.C.M.
1990-01-01
The energy balance for electrons and heavy particles constituting a plasma in partial local thermodynamic equilibrium is derived. The formulation of the energy balance used allows for evaluation of the source terms without knowledge of the particle and radiation transport situation, since most of
Equilibrium thermodynamics - Callen's postulational approach
Jongschaap, R.J.J.; Öttinger, Hans Christian
2001-01-01
In order to provide the background for nonequilibrium thermodynamics, we outline the fundamentals of equilibrium thermodynamics. Equilibrium thermodynamics must not only be obtained as a special case of any acceptable nonequilibrium generalization but, through its shining example, it also elucidates
Non-equilibrium thermodynamics
De Groot, Sybren Ruurds
1984-01-01
The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn
Quantum corrections to the stress-energy tensor in thermodynamic equilibrium with acceleration
Becattini, F.; Grossi, E.
2015-08-01
We show that the stress-energy tensor has additional terms with respect to the ideal form in states of global thermodynamic equilibrium in flat spacetime with nonvanishing acceleration and vorticity. These corrections are of quantum origin and their leading terms are second order in the gradients of the thermodynamic fields. Their relevant coefficients can be expressed in terms of correlators of the stress-energy tensor operator and the generators of the Lorentz group. With respect to previous assessments, we find that there are more second-order coefficients and that all thermodynamic functions including energy density receive acceleration and vorticity dependent corrections. Notably, also the relation between ρ and p , that is, the equation of state, is affected by acceleration and vorticity. We have calculated the corrections for a free real scalar field—both massive and massless—and we have found that they increase, particularly for a massive field, at very high acceleration and vorticity and very low temperature. Finally, these nonideal terms depend on the explicit form of the stress-energy operator, implying that different stress-energy tensors of the scalar field—canonical or improved—are thermodynamically inequivalent.
An introduction to equilibrium thermodynamics
Morrill, Bernard; Hartnett, James P; Hughes, William F
1973-01-01
An Introduction to Equilibrium Thermodynamics discusses classical thermodynamics and irreversible thermodynamics. It introduces the laws of thermodynamics and the connection between statistical concepts and observable macroscopic properties of a thermodynamic system. Chapter 1 discusses the first law of thermodynamics while Chapters 2 through 4 deal with statistical concepts. The succeeding chapters describe the link between entropy and the reversible heat process concept of entropy; the second law of thermodynamics; Legendre transformations and Jacobian algebra. Finally, Chapter 10 provides a
Fundamental functions in equilibrium thermodynamics
Horst, H.J. ter
In the standard presentations of the principles of Gibbsian equilibrium thermodynamics one can find several gaps in the logic. For a subject that is as widely used as equilibrium thermodynamics, it is of interest to clear up such questions of mathematical rigor. In this paper it is shown that using
Thermodynamic evolution far from equilibrium
Khantuleva, Tatiana A.
2018-05-01
The presented model of thermodynamic evolution of an open system far from equilibrium is based on the modern results of nonequilibrium statistical mechanics, the nonlocal theory of nonequilibrium transport developed by the author and the Speed Gradient principle introduced in the theory of adaptive control. Transition to a description of the system internal structure evolution at the mesoscopic level allows a new insight at the stability problem of non-equilibrium processes. The new model is used in a number of specific tasks.
Thermodynamic theory of equilibrium fluctuations
International Nuclear Information System (INIS)
Mishin, Y.
2015-01-01
The postulational basis of classical thermodynamics has been expanded to incorporate equilibrium fluctuations. The main additional elements of the proposed thermodynamic theory are the concept of quasi-equilibrium states, a definition of non-equilibrium entropy, a fundamental equation of state in the entropy representation, and a fluctuation postulate describing the probability distribution of macroscopic parameters of an isolated system. Although these elements introduce a statistical component that does not exist in classical thermodynamics, the logical structure of the theory is different from that of statistical mechanics and represents an expanded version of thermodynamics. Based on this theory, we present a regular procedure for calculations of equilibrium fluctuations of extensive parameters, intensive parameters and densities in systems with any number of fluctuating parameters. The proposed fluctuation formalism is demonstrated by four applications: (1) derivation of the complete set of fluctuation relations for a simple fluid in three different ensembles; (2) fluctuations in finite-reservoir systems interpolating between the canonical and micro-canonical ensembles; (3) derivation of fluctuation relations for excess properties of grain boundaries in binary solid solutions, and (4) derivation of the grain boundary width distribution for pre-melted grain boundaries in alloys. The last two applications offer an efficient fluctuation-based approach to calculations of interface excess properties and extraction of the disjoining potential in pre-melted grain boundaries. Possible future extensions of the theory are outlined.
Equilibrium thermodynamics in modified gravitational theories
International Nuclear Information System (INIS)
Bamba, Kazuharu; Geng, C.-Q.; Tsujikawa, Shinji
2010-01-01
We show that it is possible to obtain a picture of equilibrium thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density f(R,φ,X), where R is the Ricci scalar and X is the kinetic energy of a scalar field φ. This comes from a suitable definition of an energy-momentum tensor of the 'dark' component that respects to a local energy conservation in the Jordan frame. In this framework the horizon entropy S corresponding to equilibrium thermodynamics is equal to a quarter of the horizon area A in units of gravitational constant G, as in Einstein gravity. For a flat cosmological background with a decreasing Hubble parameter, S globally increases with time, as it happens for viable f(R) inflation and dark energy models. We also show that the equilibrium description in terms of the horizon entropy S is convenient because it takes into account the contribution of both the horizon entropy S in non-equilibrium thermodynamics and an entropy production term.
Blandamer, Michael J.; Cullis, Paul M.; Soldi, L. Giorgio; Engberts, Jan B.F.N.; Kacperska, Anna; Os, Nico M. van
1995-01-01
Micellar colloids are distinguished from other colloids by their association-dissociation equilibrium in solution between monomers, counter-ions and micelles. According to classical thermodynamics, the standard Gibbs energy of formation of micelles at fixed temperature and pressure can be related to
Hot nuclear matter and thermodynamical equilibrium
International Nuclear Information System (INIS)
Borderie, B.; Bacri, C.O.; Dore, D.; Frankland, J.D.; Plagnol, E.; Rivet, M.F.; Tassan-Got, L.
1999-01-01
Quasi-complete events from collisions between 36 Ar and 58 Ni corresponding to vaporized sources have been detected with the multidetector INDRA over the excitation energy range 10 - 28 AMeV. For the first time complete information concerning kinematical properties of emitted particles and chemical composition (mean values but also variances) are derived. Despite the very extreme conditions in which such sources are produced (binary collisions with short reaction times and source life-times), their properties are in agreement with the results of a statistical model including a final state excluded volume interaction and describing a gas of fermions and bosons in thermodynamical equilibrium. (authors)
Stochastic approach to equilibrium and nonequilibrium thermodynamics.
Tomé, Tânia; de Oliveira, Mário J
2015-04-01
We develop the stochastic approach to thermodynamics based on stochastic dynamics, which can be discrete (master equation) and continuous (Fokker-Planck equation), and on two assumptions concerning entropy. The first is the definition of entropy itself and the second the definition of entropy production rate, which is non-negative and vanishes in thermodynamic equilibrium. Based on these assumptions, we study interacting systems with many degrees of freedom in equilibrium or out of thermodynamic equilibrium and how the macroscopic laws are derived from the stochastic dynamics. These studies include the quasiequilibrium processes; the convexity of the equilibrium surface; the monotonic time behavior of thermodynamic potentials, including entropy; the bilinear form of the entropy production rate; the Onsager coefficients and reciprocal relations; and the nonequilibrium steady states of chemical reactions.
Relationship between dynamical entropy and energy dissipation far from thermodynamic equilibrium
Green, Jason R.; Costa, Anthony B.; Grzybowski, Bartosz A.; Szleifer, Igal
2013-01-01
Connections between microscopic dynamical observables and macroscopic nonequilibrium (NE) properties have been pursued in statistical physics since Boltzmann, Gibbs, and Maxwell. The simulations we describe here establish a relationship between the Kolmogorov–Sinai entropy and the energy dissipated as heat from a NE system to its environment. First, we show that the Kolmogorov–Sinai or dynamical entropy can be separated into system and bath components and that the entropy of the system characterizes the dynamics of energy dissipation. Second, we find that the average change in the system dynamical entropy is linearly related to the average change in the energy dissipated to the bath. The constant energy and time scales of the bath fix the dynamical relationship between these two quantities. These results provide a link between microscopic dynamical variables and the macroscopic energetics of NE processes. PMID:24065832
Non-Equilibrium Thermodynamics in Multiphase Flows
Mauri, Roberto
2013-01-01
Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...
Williams, Donald F.; Glasser, David
1991-01-01
An approach that may be used to introduce the fundamental ideas of thermodynamics using a mathematical background with the knowledge of the behavior of matter is described. The physical background, conservation of energy, predicting the behavior of a system, and solving problems are topics of discussion. (KR)
Thermodynamics and energy conversion
Struchtrup, Henning
2014-01-01
This textbook gives a thorough treatment of engineering thermodynamics with applications to classical and modern energy conversion devices. Some emphasis lies on the description of irreversible processes, such as friction, heat transfer and mixing, and the evaluation of the related work losses. Better use of resources requires high efficiencies, therefore the reduction of irreversible losses should be seen as one of the main goals of a thermal engineer. This book provides the necessary tools. Topics include: car and aircraft engines, including Otto, Diesel and Atkinson cycles, by-pass turbofan engines, ramjet and scramjet; steam and gas power plants, including advanced regenerative systems, solar tower, and compressed air energy storage; mixing and separation, including reverse osmosis, osmotic powerplants, and carbon sequestration; phase equilibrium and chemical equilibrium, distillation, chemical reactors, combustion processes, and fuel cells; the microscopic definition of entropy. The book i...
Equilibrium and out-of-equilibrium thermodynamics in supercooled liquids and glasses
International Nuclear Information System (INIS)
Mossa, S; Nave, E La; Tartaglia, P; Sciortino, F
2003-01-01
We review the inherent structure thermodynamical formalism and the formulation of an equation of state (EOS) for liquids in equilibrium based on the (volume) derivatives of the statistical properties of the potential energy surface. We also show that, under the hypothesis that during ageing the system explores states associated with equilibrium configurations, it is possible to generalize the proposed EOS to out-of-equilibrium (OOE) conditions. The proposed formulation is based on the introduction of one additional parameter which, in the chosen thermodynamic formalism, can be chosen as the local minimum where the slowly relaxing OOE liquid is trapped
Thermodynamic equilibrium in relativistic rotating systems
International Nuclear Information System (INIS)
Suen, W.M.; Washington Univ., St. Louis, MO; Young, K.
1988-01-01
The thermodynamic equilibrium configurations of relativistic rotating stars are studied using the maximum entropy principle. It is shown that the heuristic arguments for the equilibrium conditions can be developed into a maximum entropy principle in which the variations are carried out in a fixed background spacetime. This maximum principle with the fixed background assumption is technically simpler than, but has to be justified by, a maximum entropy principle without the assumption. Such a maximum entropy principle is formulated in this paper, showing that the general relativistic system can be treated on the same footing as other long-range force systems. (author)
Thermodynamic and transport properties of gaseous tetrafluoromethane in chemical equilibrium
Hunt, J. L.; Boney, L. R.
1973-01-01
Equations and in computer code are presented for the thermodynamic and transport properties of gaseous, undissociated tetrafluoromethane (CF4) in chemical equilibrium. The computer code calculates the thermodynamic and transport properties of CF4 when given any two of five thermodynamic variables (entropy, temperature, volume, pressure, and enthalpy). Equilibrium thermodynamic and transport property data are tabulated and pressure-enthalpy diagrams are presented.
Chemical Equilibrium as Balance of the Thermodynamic Forces
Zilbergleyt, B.
2004-01-01
The article sets forth comprehensive basics of thermodynamics of chemical equilibrium as balance of the thermodynamic forces. Based on the linear equations of irreversible thermodynamics, De Donder definition of the thermodynamic force, and Le Chatelier's principle, new thermodynamics of chemical equilibrium offers an explicit account for multiple chemical interactions within the system. Basic relations between energetic characteristics of chemical transformations and reaction extents are bas...
Thermodynamics Far from Equilibrium: from Glasses to Black Holes
Nieuwenhuizen, Th. M.
2001-01-01
A framework for the non-equilibrium thermodynamics of glasses is discussed. It also explains the non-equilibrium thermodynamics of a black hole isolated from matter. The first and second laws of black dynamics and black hole thermodynamics are shown to coincide, while the third laws deal with different issues.
Ren, Hai-Sheng; Ming, Mei-Jun; Ma, Jian-Yi; Li, Xiang-Yuan
2013-08-22
Within the framework of constrained density functional theory (CDFT), the diabatic or charge localized states of electron transfer (ET) have been constructed. Based on the diabatic states, inner reorganization energy λin has been directly calculated. For solvent reorganization energy λs, a novel and reasonable nonequilibrium solvation model is established by introducing a constrained equilibrium manipulation, and a new expression of λs has been formulated. It is found that λs is actually the cost of maintaining the residual polarization, which equilibrates with the extra electric field. On the basis of diabatic states constructed by CDFT, a numerical algorithm using the new formulations with the dielectric polarizable continuum model (D-PCM) has been implemented. As typical test cases, self-exchange ET reactions between tetracyanoethylene (TCNE) and tetrathiafulvalene (TTF) and their corresponding ionic radicals in acetonitrile are investigated. The calculated reorganization energies λ are 7293 cm(-1) for TCNE/TCNE(-) and 5939 cm(-1) for TTF/TTF(+) reactions, agreeing well with available experimental results of 7250 cm(-1) and 5810 cm(-1), respectively.
The thermodynamic solar energy
International Nuclear Information System (INIS)
Rivoire, B.
2002-04-01
The thermodynamic solar energy is the technic in the whole aiming to transform the solar radiation energy in high temperature heat and then in mechanical energy by a thermodynamic cycle. These technic are most often at an experimental scale. This paper describes and analyzes the research programs developed in the advanced countries, since 1980. (A.L.B.)
Classical or equilibrium thermodynamics: basic conceptual aspects
Directory of Open Access Journals (Sweden)
Luiz Augusto Calvo Tiritan
2008-08-01
Full Text Available The Classical or Equilibrium Thermodynamics is one of the most consolidated fields of Physics. It is synthesized by a well-known and self coherent knowledge structure. The essence of the Classical Thermodynamics theoretical structure consists of a set of natural laws that rule the macroscopic physical systems behavior. These laws were formulated based on observations generalizations and are mostly independent of any hypotheses concerning the microscopic nature of the matter. In general, the approaches established for the Classical Thermodynamics follow one of the following alternatives: the historical approach that describes chronologically the evolution of ideas, concepts and facts, and the postulational approach in which postulates are formulated but are not demonstrated a priori but can be confirmed a posteriori. In this work, a brief review of the pre-classical historical approach conceptual evolution is elaborated, from the beginning of the seventeenth century to the middle of the nineteenth century. As for this, the following themes are dealt with in an evolutionary and phenomenological way: heat nature, thermometry, calorimetry, Carnot’s heat engine, heat mechanical equivalent and the first and second laws. The Zeroth law that was formulated afterwards is included in the discussion.
Teaching Chemical Equilibrium and Thermodynamics in Undergraduate General Chemistry Classes.
Banerjee, Anil C.
1995-01-01
Discusses some of the conceptual difficulties encountered by undergraduate students in learning certain aspects of chemical equilibrium and thermodynamics. Discusses teaching strategies for dealing with these difficulties. (JRH)
Extended irreversible thermodynamics and non-equilibrium temperature
Directory of Open Access Journals (Sweden)
Casas-Vazquez, Jose'
2008-02-01
Full Text Available We briefly review the concept of non-equilibrium temperature from the perspectives of extended irreversible thermodynamics, fluctuation theory, and statistical mechanics. The relations between different proposals are explicitly examined in two especially simple systems: an ideal gas in steady shear flow and a forced harmonic oscillator in a thermal bath. We examine with special detail temperatures related to the average molecular kinetic energy along different spatial directions, to the average configurational energy, to the derivative of the entropy with respect to internal energy, to fluctuation-dissipation relation and discuss their measurement.
Equilibrium Molecular Thermodynamics from Kirkwood Sampling
Somani, Sandeep; Okamoto, Yuko; Ballard, Andrew J.; Wales, David J.
2015-01-01
We present two methods for barrierless equilibrium sampling of molecular systems based on the recently proposed Kirkwood method (J. Chem. Phys. 2009, 130, 134102). Kirkwood sampling employs low-order correlations among internal coordinates of a molecule for random (or non-Markovian) sampling of the high dimensional conformational space. This is a geometrical sampling method independent of the potential energy surface. The first method is a variant of biased Monte Carlo, wher...
On the forces and fluxes in non-equilibrium thermodynamics
International Nuclear Information System (INIS)
Kitahara, Kazuo
1986-01-01
A formulation of non-equilibrium thermodynamics of continuum systems based on local equilibrium assumption is reported. Thermodynamic forces are defined from a generalized local entropy and irreversible fluxes are defined as non-advective parts of fluxes of conservative quantities. The validity of the general evolution criterion and its generalization is discussed. (author)
Silverberg, Lee J.; Raff, Lionel M.
2015-01-01
Thermodynamic spontaneity-equilibrium criteria require that in a single-reaction system, reactions in either the forward or reverse direction at equilibrium be nonspontaneous. Conversely, the concept of dynamic equilibrium holds that forward and reverse reactions both occur at equal rates at equilibrium to the extent allowed by kinetic…
Non-Equilibrium Thermodynamics of Self-Replicating Protocells
DEFF Research Database (Denmark)
Fellermann, Harold; Corominas-Murtra, Bernat; Hansen, Per Lyngs
2018-01-01
We provide a non-equilibrium thermodynamic description of the life-cycle of a droplet based, chemically feasible, system of protocells. By coupling the protocells metabolic kinetics with its thermodynamics, we demonstrate how the system can be driven out of equilibrium to ensure protocell growth...... and replication. This coupling allows us to derive the equations of evolution and to rigorously demonstrate how growth and replication life-cycle can be understood as a non-equilibrium thermodynamic cycle. The process does not appeal to genetic information or inheritance, and is based only on non......-equilibrium physics considerations. Our non-equilibrium thermodynamic description of simple, yet realistic, processes of protocell growth and replication, represents an advance in our physical understanding of a central biological phenomenon both in connection to the origin of life and for modern biology....
Finite-size polyelectrolyte bundles at thermodynamic equilibrium
Sayar, M.; Holm, C.
2007-01-01
We present the results of extensive computer simulations performed on solutions of monodisperse charged rod-like polyelectrolytes in the presence of trivalent counterions. To overcome energy barriers we used a combination of parallel tempering and hybrid Monte Carlo techniques. Our results show that for small values of the electrostatic interaction the solution mostly consists of dispersed single rods. The potential of mean force between the polyelectrolyte monomers yields an attractive interaction at short distances. For a range of larger values of the Bjerrum length, we find finite-size polyelectrolyte bundles at thermodynamic equilibrium. Further increase of the Bjerrum length eventually leads to phase separation and precipitation. We discuss the origin of the observed thermodynamic stability of the finite-size aggregates.
EquilTheTA: Thermodynamic and transport properties of complex equilibrium plasmas
International Nuclear Information System (INIS)
Colonna, G.; D'Angola, A.
2012-01-01
EquilTheTA (EQUILibrium for plasma THErmodynamics and Transport Applications) is a web-based software which calculates chemical equilibrium product concentrations from any set of reactants and determines thermodynamic and transport properties for the product mixture in wide temperature and pressure ranges. The program calculates chemical equilibrium by using a hierarchical approach, thermodynamic properties and transport coefficients starting from recent and accurate databases of atomic and molecular energy levels and collision integrals. In the calculations, Debye length and cut-off are consistently updated and virial corrections (up to third order) can be considered. Transport coefficients are calculated by using high order approximations of the Chapman-Enskog method.
Electrolytes: transport properties and non-equilibrium thermodynamics
International Nuclear Information System (INIS)
Miller, D.G.
1980-12-01
This paper presents a review on the application of non-equilibrium thermodynamics to transport in electrolyte solutions, and some recent experimental work and results for mutual diffusion in electrolyte solutions
College Physical Chemistry Students' Conceptions of Equilibrium and Fundamental Thermodynamics.
Thomas, Peter L.; Schwenz, Richard W.
1998-01-01
Focuses on many alternative conceptions and nonconceptions about material related to equilibrium and thermodynamics. Uses interviews and compares the concepts from these with those expressed by experts in textbooks. (DDR)
Methane on Mars: Thermodynamic Equilibrium and Photochemical Calculations
Levine, J. S.; Summers, M. E.; Ewell, M.
2010-01-01
The detection of methane (CH4) in the atmosphere of Mars by Mars Express and Earth-based spectroscopy is very surprising, very puzzling, and very intriguing. On Earth, about 90% of atmospheric ozone is produced by living systems. A major question concerning methane on Mars is its origin - biological or geological. Thermodynamic equilibrium calculations indicated that methane cannot be produced by atmospheric chemical/photochemical reactions. Thermodynamic equilibrium calculations for three gases, methane, ammonia (NH3) and nitrous oxide (N2O) in the Earth s atmosphere are summarized in Table 1. The calculations indicate that these three gases should not exist in the Earth s atmosphere. Yet they do, with methane, ammonia and nitrous oxide enhanced 139, 50 and 12 orders of magnitude above their calculated thermodynamic equilibrium concentration due to the impact of life! Thermodynamic equilibrium calculations have been performed for the same three gases in the atmosphere of Mars based on the assumed composition of the Mars atmosphere shown in Table 2. The calculated thermodynamic equilibrium concentrations of the same three gases in the atmosphere of Mars is shown in Table 3. Clearly, based on thermodynamic equilibrium calculations, methane should not be present in the atmosphere of Mars, but it is in concentrations approaching 30 ppbv from three distinct regions on Mars.
1976-01-01
The entropy of a gas system with the number of particles subject to external control is maximized to derive relations between the thermodynamic variables that obtain at equilibrium. These relations are described in terms of the chemical potential, defined as equivalent partial derivatives of entropy, energy, enthalpy, free energy, or free enthalpy. At equilibrium, the change in total chemical potential must vanish. This fact is used to derive the equilibrium constants for chemical reactions in terms of the partition functions of the species involved in the reaction. Thus the equilibrium constants can be determined accurately, just as other thermodynamic properties, from a knowledge of the energy levels and degeneracies for the gas species involved. These equilibrium constants permit one to calculate the equilibrium concentrations or partial pressures of chemically reacting species that occur in gas mixtures at any given condition of pressure and temperature or volume and temperature.
Supersymmetric Field Theory of Non-Equilibrium Thermodynamic System
Olemskoi, Alexander I.; Brazhnyi, Valerii A.
1998-01-01
On the basis of Langevin equation the optimal SUSY field scheme is formulated to discribe a non-equilibrium thermodynamic system with quenched disorder and non-ergodicity effects. Thermodynamic and isothermal susceptibilities, memory parameter and irreversible response are determined at different temperatures and quenched disorder intensities.
International Nuclear Information System (INIS)
Du, Jianping; Zhao, Ruihua; Xue, Yongqiang
2012-01-01
Highlights: ► There is an obvious influence of the size on thermodynamic properties for the reaction referring nano-reactants. ► Gibbs function, enthalpy, entropy and equilibrium constant are dependent on the reactant size. ► There is an approximate linear relation between them. - Abstract: The theoretical relations of thermodynamic properties, the equilibrium constant and reactant size in nanosystem are described. The effects of size on thermodynamic properties and the equilibrium constant were studied using nanosize zinc oxide and sodium bisulfate solution as a reaction system. The experimental results indicated that the molar Gibbs free energy, the molar enthalpy and the molar entropy of the reaction decrease, but the equilibrium constant increases with decreasing reactant size. Linear trends were observed between the reciprocal of size for nano-reactant and thermodynamic variable, which are consistent with the theoretical relations.
Considerations on non equilibrium thermodynamics of interactions
Lucia, Umberto
2016-04-01
Nature can be considered the ;first; engineer! For scientists and engineers, dynamics and evolution of complex systems are not easy to predict. A fundamental approach to study complex system is thermodynamics. But, the result is the origin of too many schools of thermodynamics with a consequent difficulty in communication between thermodynamicists and other scientists and, also, among themselves. The solution is to obtain a unified approach based on the fundamentals of physics. Here we suggest a possible unification of the schools of thermodynamics starting from two fundamental concepts of physics, interaction and flows.
Non-equilibrium thermodynamics in cells.
Jülicher, Frank; Grill, Stephan W; Salbreux, Guillaume
2018-03-15
We review the general hydrodynamic theory of active soft materials that is motivated in partic- ular by biological matter. We present basic concepts of irreversible thermodynamics of spatially extended multicomponent active systems. Starting from the rate of entropy production, we iden- tify conjugate thermodynamic fluxes and forces and present generic constitutive equations of polar active fluids and active gels. We also discuss angular momentum conservation which plays a role in the the physics of active chiral gels. The irreversible thermodynamics of active gels provides a general framework to discuss the physics that underlies a wide variety of biological processes in cells and in multicellular tissues. © 2018 IOP Publishing Ltd.
Statistical thermodynamics of equilibrium polymers at interfaces
Gucht, van der J.; Besseling, N.A.M.
2002-01-01
The behavior of a solution of equilibrium polymers (or living polymers) at an interface is studied, using a Bethe-Guggenheim lattice model for molecules with orientation dependent interactions. The density profile of polymers and the chain length distribution are calculated. For equilibrium polymers
Energy Technology Data Exchange (ETDEWEB)
Sousa, Tania; Domingos, Tiago [Environment and Energy Section, DEM, Instituto Superior Tecnico, Avenida Rovisco Pais, 1, 1049-001 Lisboa (Portugal)
2006-06-10
The relation between Thermodynamics and Economics is a paramount issue in Ecological Economics. Two different levels can be distinguished when discussing it: formal and substantive. At the formal level, a mathematical framework is used to describe both thermodynamic and economic systems. At the substantive level, thermodynamic laws are applied to economic processes. In Ecological Economics, there is a widespread claim that neoclassical economics has the same mathematical formulation as classical mechanics and is therefore fundamentally flawed because: (1) utility does not obey a conservation law as energy does; (2) an equilibrium theory cannot be used to study irreversible processes. Here, we show that neoclassical economics is based on a wrong formulation of classical mechanics, being in fact formally analogous to equilibrium thermodynamics. The similarity between both formalisms, namely that they are both cases of constrained optimisation, is easily perceived when thermodynamics is looked upon using the Tisza-Callen axiomatisation. In this paper, we take the formal analogy between equilibrium thermodynamics and economic systems far enough to answer the formal criticisms, proving that the formalism of neoclassical economics has irreversibility embedded in it. However, the formal similarity between equilibrium thermodynamics and neoclassical microeconomics does not mean that economic models are in accordance with mass, energy and entropy balance equations. In fact, neoclassical theory suffers from flaws in the substantive integration with thermodynamic laws as has already been fully demonstrated by valuable work done by ecological economists in this field. (author)
Thermodynamic equilibrium-air correlations for flowfield applications
Zoby, E. V.; Moss, J. N.
1981-01-01
Equilibrium-air thermodynamic correlations have been developed for flowfield calculation procedures. A comparison between the postshock results computed by the correlation equations and detailed chemistry calculations is very good. The thermodynamic correlations are incorporated in an approximate inviscid flowfield code with a convective heating capability for the purpose of defining the thermodynamic environment through the shock layer. Comparisons of heating rates computed by the approximate code and a viscous-shock-layer method are good. In addition to presenting the thermodynamic correlations, the impact of several viscosity models on the convective heat transfer is demonstrated.
Computation of thermodynamic equilibrium in systems under stress
Vrijmoed, Johannes C.; Podladchikov, Yuri Y.
2016-04-01
Metamorphic reactions may be partly controlled by the local stress distribution as suggested by observations of phase assemblages around garnet inclusions related to an amphibolite shear zone in granulite of the Bergen Arcs in Norway. A particular example presented in fig. 14 of Mukai et al. [1] is discussed here. A garnet crystal embedded in a plagioclase matrix is replaced on the left side by a high pressure intergrowth of kyanite and quartz and on the right side by chlorite-amphibole. This texture apparently represents disequilibrium. In this case, the minerals adapt to the low pressure ambient conditions only where fluids were present. Alternatively, here we compute that this particular low pressure and high pressure assemblage around a stressed rigid inclusion such as garnet can coexist in equilibrium. To do the computations we developed the Thermolab software package. The core of the software package consists of Matlab functions that generate Gibbs energy of minerals and melts from the Holland and Powell database [2] and aqueous species from the SUPCRT92 database [3]. Most up to date solid solutions are included in a general formulation. The user provides a Matlab script to do the desired calculations using the core functions. Gibbs energy of all minerals, solutions and species are benchmarked versus THERMOCALC, PerpleX [4] and SUPCRT92 and are reproduced within round off computer error. Multi-component phase diagrams have been calculated using Gibbs minimization to benchmark with THERMOCALC and Perple_X. The Matlab script to compute equilibrium in a stressed system needs only two modifications of the standard phase diagram script. Firstly, Gibbs energy of phases considered in the calculation is generated for multiple values of thermodynamic pressure. Secondly, for the Gibbs minimization the proportion of the system at each particular thermodynamic pressure needs to be constrained. The user decides which part of the stress tensor is input as thermodynamic
Coronal and local thermodynamic equilibriums in a hollow cathode discharge
International Nuclear Information System (INIS)
Zheng Xutao
2005-01-01
A characteristic two-section profile of excited-state populations is observed in a hollow cathode discharge and is explained by coexistence of the coronal equilibrium (CE) and the local thermodynamic equilibrium (LTE). At helium pressure 0.1 Torr and cathode current 200-300 mA, vacuum ultraviolet radiations from He I 1snp 1 P (n=2-16) and He II np 2 P (n=2-14) are resolved with a 2.2-M McPherson spectrometer. Relative populations of these states are deduced from the discrete line intensities and are plotted against energy levels. For both the He I and He II series, as energy level increases, populations of high-n (n>10) states are found to decrease much more quickly than low-n (n<7) populations. While low-n populations are described with the CE dominated by direct electron-impact excitations, high-n populations are fitted with the LTE to calculate the population temperatures of gas atoms and ions. Validities of the CE and LTE in different n-ranges are considered on the competition between radiative decays of the excited states and their collisions with gas atoms. (author)
Non-equilibrium thermodynamics and physical kinetics
Bikkin, Halid
2014-01-01
This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.
Experimental determination of thermodynamic equilibrium in biocatalytic transamination.
Tufvesson, Pär; Jensen, Jacob S; Kroutil, Wolfgang; Woodley, John M
2012-08-01
The equilibrium constant is a critical parameter for making rational design choices in biocatalytic transamination for the synthesis of chiral amines. However, very few reports are available in the scientific literature determining the equilibrium constant (K) for the transamination of ketones. Various methods for determining (or estimating) equilibrium have previously been suggested, both experimental as well as computational (based on group contribution methods). However, none of these were found suitable for determining the equilibrium constant for the transamination of ketones. Therefore, in this communication we suggest a simple experimental methodology which we hope will stimulate more accurate determination of thermodynamic equilibria when reporting the results of transaminase-catalyzed reactions in order to increase understanding of the relationship between substrate and product molecular structure on reaction thermodynamics. Copyright © 2012 Wiley Periodicals, Inc.
Thermodynamics of ion exchange equilibrium for some uni ...
African Journals Online (AJOL)
The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br-, and uni-divalent Cl-/SO42-, Cl-/C2O42- reaction systems was carried out using ion exchange resin Indion FF-IP. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as ...
Westerhoff, Hans V.; Lolkema, Juke S.; Otto, Roel; Hellingwerf, K
1982-01-01
Microbial growth is analyzed in terms of mosaic and phenomenological non-equilibrium thermodynamics. It turns out that already existing parameters devised to measure bacterial growth, such as YATP, µ, and Qsubstrate, have as thermodynamic equivalents flow ratio, output flow and input flow. With this
Thermodynamics of the Rhodamine B Lactone--Zwitterion Equilibrium.
Hinckley, Daniel A.; Seybold, Paul G.
1987-01-01
Discusses the benefits of thermochromic transformations for studying thermodynamic properties. Describes an experiment that uses a commercially available dye, attains equilibrium rapidly, employs a simple, single-beam spectrophotometer, and is suitable for both physical chemistry and introductory chemistry laboratories. (TW)
Kinetic, Equilibrium and thermodynamic studies on the biosorption ...
African Journals Online (AJOL)
The kinetics, equilibrium and thermodynamics of the biosorption of Cd (II) from aqueous solution by the leaf biomass of Calotropis procera popularly known in western Nigeria as 'bom bom'and genrally known as Sodom apple were investigated at different experimental conditions. Optimum conditions of pH, contact time, ...
Thermodynamic equilibrium and heavy particles near a black hole
Energy Technology Data Exchange (ETDEWEB)
Zeldovich, Ya B [AN SSSR, Moscow
1976-02-23
The purpose of this letter is to point out, that thermodynamic equilibrium in general relativity corresponds to T(r)=Tsub(infinity)g/sub 00/sup(-1/2)=Tsub(infinity)..sqrt..(r/(r-rsub(g))). The last expression is written for a static non-rotating (Schwarzschild) black hole.
Glavatskiy, K S
2015-10-28
Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called "mirror-image" systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval.
International Nuclear Information System (INIS)
Glavatskiy, K. S.
2015-01-01
Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called “mirror-image” systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval
Equilibrium and thermodynamics of azo dyes biosorption onto Spirulina platensis
Directory of Open Access Journals (Sweden)
G. L. Dotto
2013-03-01
Full Text Available The equilibrium and thermodynamics of azo dye (tartrazine and allura red biosorption onto Spirulina platensis biomass were investigated. The equilibrium curves were obtained at 298, 308, 318 and 328 K, and four isotherm models were fitted the experimental data. Biosorption thermodynamic parameters (ΔG, ΔH and ΔS were estimated. The results showed that the biosorption was favored by a temperature decrease. For both dyes, the Sips model was the best to represent the equilibrium experimental data (R²>0.99 and ARE<5.0% and the maximum biosorption capacities were 363.2 and 468.7 mg g-1 for tartrazine and allura red, respectively, obtained at 298 K. The negative values of ΔG and ΔH showed that the biosorption of both dyes was spontaneous, favorable and exothermic. The positive values of ΔS suggested that the system disorder increases during the biosorption process.
Stochastic thermodynamics of quantum maps with and without equilibrium.
Barra, Felipe; Lledó, Cristóbal
2017-11-01
We study stochastic thermodynamics for a quantum system of interest whose dynamics is described by a completely positive trace-preserving (CPTP) map as a result of its interaction with a thermal bath. We define CPTP maps with equilibrium as CPTP maps with an invariant state such that the entropy production due to the action of the map on the invariant state vanishes. Thermal maps are a subgroup of CPTP maps with equilibrium. In general, for CPTP maps, the thermodynamic quantities, such as the entropy production or work performed on the system, depend on the combined state of the system plus its environment. We show that these quantities can be written in terms of system properties for maps with equilibrium. The relations that we obtain are valid for arbitrary coupling strengths between the system and the thermal bath. The fluctuations of thermodynamic quantities are considered in the framework of a two-point measurement scheme. We derive the entropy production fluctuation theorem for general maps and a fluctuation relation for the stochastic work on a system that starts in the Gibbs state. Some simplifications for the probability distributions in the case of maps with equilibrium are presented. We illustrate our results by considering spin 1/2 systems under thermal maps, nonthermal maps with equilibrium, maps with nonequilibrium steady states, and concatenations of them. Finally, and as an important application, we consider a particular limit in which the concatenation of maps generates a continuous time evolution in Lindblad form for the system of interest, and we show that the concept of maps with and without equilibrium translates into Lindblad equations with and without quantum detailed balance, respectively. The consequences for the thermodynamic quantities in this limit are discussed.
Thermodynamic analysis of environmental problems of energy
Directory of Open Access Journals (Sweden)
Kaganovich Boris M.
2017-01-01
Full Text Available The paper discusses the problems of the ecological analysis of physicochemical processes in power units and the impact of energy systems on the nature in large territorial regions. The model of extreme intermediate states developed at the Energy Systems Institute based on the principles of classical equilibrium thermodynamics was chosen to devise specific computational methods. The results of the conducted studies are presented and directions for further work are outlined.
Analysis of radioactive-matter interaction near thermodynamical equilibrium states
International Nuclear Information System (INIS)
Damamme, G.
1993-01-01
We study the absorption/emission process of photon by matter in the framework of a radiativo-collisionnal model of atom, a thermodynamical approach being used. The considered matter description is the atomic sphere one. First we give the expression of the balance equation around an equilibrium state. Then we express the atomic populations in function of the characteristics of the radiation and of the free electrons and of their time history. This permit us to interpret the photon balance as being due to true emission/absorption process of photons as well as fluorescence terms, all these processes being affected by relaxation effects. The total energy balance between matter and radiation can also be analyzed in the same way and conduct to introduce one photon effective interactions terms for each radiative proper mode, terms also affected by retardation effects. Such a taking into account of atom populations has no consequence on the radiative flux equation (i.e. the transfer opacity) but can considerably modify the energy balance between matter and radiation. (author). 11 refs., 3 figs
Quantum thermodynamics of nanoscale steady states far from equilibrium
Taniguchi, Nobuhiko
2018-04-01
We develop an exact quantum thermodynamic description for a noninteracting nanoscale steady state that couples strongly with multiple reservoirs. We demonstrate that there exists a steady-state extension of the thermodynamic function that correctly accounts for the multiterminal Landauer-Büttiker formula of quantum transport of charge, energy, or heat via the nonequilibrium thermodynamic relations. Its explicit form is obtained for a single bosonic or fermionic level in the wide-band limit, and corresponding thermodynamic forces (affinities) are identified. Nonlinear generalization of the Onsager reciprocity relations are derived. We suggest that the steady-state thermodynamic function is also capable of characterizing the heat current fluctuations of the critical transport where the thermal fluctuations dominate. Also, the suggested nonequilibrium steady-state thermodynamic relations seemingly persist for a spin-degenerate single level with local interaction.
International Nuclear Information System (INIS)
Hayasaka, Hideo
1983-01-01
The thermodynamics and the energy distribution function of the neutron gas in a constant power reactor are considered, taking into account the burn-up of fuel. To separate the secular motion of neutrons owing to fuel burn-up and the microscopic fluctuations of neutrons around this motion, a long time of the order of several months is divided into m equal intervals, and the respective states corresponding to m small time intervals are treated as quasi-stationary states. The local energy distribution function of the neutron gas in the quasi-stationary state is given by a generalized Boltzmann distribution specified by the respective generalized activity coefficient for each subsystem. The effects of fuel burn-up on the respective distribution functions for successive small time intervals are taken into account through various quantities relating to reactor physics, depending upon the fuel burn-up, by successive approximation. (author)
Equilibrium sampling for a thermodynamic assessment of contaminated sediments
DEFF Research Database (Denmark)
) govern diffusive uptake and partitioning. Equilibrium sampling of sediment was introduced 15 years ago to measure Cfree, and it has since developed into a straightforward, precise and sensitive approach for determining Cfree and other exposure parameters that allow for thermodynamic assessment...... of polluted sediments. Glass jars with µm-thin silicone coatings on the inner walls can be used for ex situ equilibration while a device housing several silicone-coated fibers can be used for in situ equilibration. In both cases, parallel sampling with varying silicone thicknesses can be applied to confirm...... will focus at the latest developments in equilibrium sampling concepts and methods. Further, we will explain how these approaches can provide a new basis for a thermodynamic assessment of polluted sediments....
Understanding Non-equilibrium Thermodynamics Foundations, Applications, Frontiers
Jou, David; Lebon, Georgy
2007-01-01
This book offers a homogeneous presentation of the many faces of non-equilibrium thermodynamics. The first part is devoted to a description of the nowadays thermodynamic formalism recognized as the classical theory of non-equilibrium processes. This part of the book may serve as a basis to an introductory course dedicated to first-year graduate students in sciences and engineering. The classical description can however not be complete, as it rests on the hypothesis of local equilibrium. This has fostered the development of many theories going beyond local equilibrium and which cannot be put aside. The second part of the book is concerned with these different approaches, and will be of special interest for PhD students and researchers. For the sake of homogeneity, the authors have used the general structure and methods presented in the first part. Indeed, besides their differences, all these formalisms are not closed boxes but present some overlappings and parallelisms which are emphasized in this book. For pe...
International Nuclear Information System (INIS)
Alvarez-Romero, J. T.
2006-01-01
We present a discussion to show that the absorbed dose D is a time-dependent function. This time dependence is demonstrated based on the concepts of charged particle equilibrium and on radiation equilibrium within the context of thermodynamic non-equilibrium. In the latter, the time dependence is due to changes of the rest mass energy of the nuclei and elementary particles involved in the terms ΣQ and Q that appear in the definitions of energy imparted ε and energy deposit ε i , respectively. In fact, nothing is said about the averaging operation of the non-stochastic quantity mean energy imparted ε-bar, which is used in the definition of D according to ICRU 60. It is shown in this research that the averaging operation necessary to define the ε-bar employed to get D cannot be performed with an equilibrium statistical operator ρ(r) as could be expected. Rather, the operation has to be defined with a time-dependent non-equilibrium statistical operator (r, t) therefore, D is a time-dependent function D(r, t). (authors)
The Rate-Controlled Constrained-Equilibrium Approach to Far-From-Local-Equilibrium Thermodynamics
Directory of Open Access Journals (Sweden)
Hameed Metghalchi
2012-01-01
Full Text Available The Rate-Controlled Constrained-Equilibrium (RCCE method for the description of the time-dependent behavior of dynamical systems in non-equilibrium states is a general, effective, physically based method for model order reduction that was originally developed in the framework of thermodynamics and chemical kinetics. A generalized mathematical formulation is presented here that allows including nonlinear constraints in non-local equilibrium systems characterized by the existence of a non-increasing Lyapunov functional under the system’s internal dynamics. The generalized formulation of RCCE enables to clarify the essentials of the method and the built-in general feature of thermodynamic consistency in the chemical kinetics context. In this paper, we work out the details of the method in a generalized mathematical-physics framework, but for definiteness we detail its well-known implementation in the traditional chemical kinetics framework. We detail proofs and spell out explicit functional dependences so as to bring out and clarify each underlying assumption of the method. In the standard context of chemical kinetics of ideal gas mixtures, we discuss the relations between the validity of the detailed balance condition off-equilibrium and the thermodynamic consistency of the method. We also discuss two examples of RCCE gas-phase combustion calculations to emphasize the constraint-dependent performance of the RCCE method.
Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads
International Nuclear Information System (INIS)
Bai, Jing; Fan, Fangli; Wu, Xiaolei; Tian, Wei; Zhao, Liang; Yin, Xiaojie; Fan, Fuyou; Li, Zhan; Tian, Longlong; Wang, Yang; Qin, Zhi; Guo, Junsheng
2013-01-01
Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH 0 , ΔS 0 and ΔG 0 were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous. -- Highlights: • Equilibrium, kinetics and thermodynamics of uranium sorption by CaAlg were studied. • Equilibrium studies show that Langmuir isotherm better fit with experimental data. • Pseudo-second-order kinetics model is found to be well depicting the kinetic data. • Thermodynamic study shows that the sorption process is endothermic and spontaneous
Thermodynamics of open, nonisothermal chemical systems far from equilibrium
International Nuclear Information System (INIS)
Yoshida, Nobuo
1992-01-01
The thermodynamic behavior of kinetic models based on a continuously stirred tank reactor (CSTR) is studied in an attempt to seek general trends in the thermodynamic properties of open nonlinear systems. The models consist of two reversible reactions, A + nB rightleftharpoons (n + 1) B (n = 0,1,or 2) and B rightleftharpoons C, taking place in an adiabatic CSTR. The heat of reaction is incorporated, and the rate constants are assumed to follow an Arrhenius temperature dependence. The models give rise to multiple stationary states and sustained oscillations (limit cycles). The entropy difference between stationary or oscillatory states and equilibrium and the rate of entropy production in the these states are calculated as a function of the residence time in the reactor. The entropy difference and entropy production may be taken, to some extent, as indicative of the influence of irreversible processes, which disappears at equilibrium. The results of the calculations reveal the following systematic trends: (I) The entropy difference or entropy production for stable states or both always increase as the residence time is shortened, namely, as the system is displaced further from equilibrium. (II) If stable and unstable states (stationary or oscillatory) coexist under identical conditions, then the stable state invariably has a smaller value of the entropy difference or entropy production or both than the corresponding unstable state. 26 refs., 3 figs
Sousa, Tânia; Domingos, Tiago
2006-11-01
We develop a unified conceptual and mathematical structure for equilibrium econophysics, i.e., the use of concepts and tools of equilibrium thermodynamics in neoclassical microeconomics and vice versa. Within this conceptual structure the results obtained in microeconomic theory are: (1) the definition of irreversibility in economic behavior; (2) the clarification that the Engel curve and the offer curve are not descriptions of real processes dictated by the maximization of utility at constant endowment; (3) the derivation of a relation between elasticities proving that economic elasticities are not all independent; (4) the proof that Giffen goods do not exist in a stable equilibrium; (5) the derivation that ‘economic integrability’ is equivalent to the generalized Le Chatelier principle and (6) the definition of a first order phase transition, i.e., a transition between separate points in the utility function. In thermodynamics the results obtained are: (1) a relation between the non-dimensional isothermal and adiabatic compressibilities and the increase or decrease in the thermodynamic potentials; (2) the distinction between mathematical integrability and optimization behavior and (3) the generalization of the Clapeyron equation.
Effect of configuration widths on the spectra of local thermodynamic equilibrium plasmas
International Nuclear Information System (INIS)
Bar-Shalom, A.; Oreg, J.; Goldstein, W.H.
1995-01-01
We present the extension of the supertransition-array (STA) theory to include configuration widths in the spectra of local thermodynamic equilibrium (LTE) plasmas. Exact analytic expressions for the moments of a STA are given, accounting for the detailed contributions of individual levels within the configurations that belong to a STA. The STA average energy is shifted and an additional term appears in its variance. Various cases are presented, demonstrating the effect of these corrections on the LTE spectrum
Dotov, D G; Kim, S; Frank, T D
2015-02-01
We derive explicit expressions for the non-equilibrium thermodynamical variables of a canonical-dissipative limit cycle oscillator describing rhythmic motion patterns of active systems. These variables are statistical entropy, non-equilibrium internal energy, and non-equilibrium free energy. In particular, the expression for the non-equilibrium free energy is derived as a function of a suitable control parameter. The control parameter determines the Hopf bifurcation point of the deterministic active system and describes the effective pumping of the oscillator. In analogy to the equilibrium free energy of the Landau theory, it is shown that the non-equilibrium free energy decays as a function of the control parameter. In doing so, a similarity between certain equilibrium and non-equilibrium phase transitions is pointed out. Data from an experiment on human rhythmic movements is presented. Estimates for pumping intensity as well as the thermodynamical variables are reported. It is shown that in the experiment the non-equilibrium free energy decayed when pumping intensity was increased, which is consistent with the theory. Moreover, pumping intensities close to zero could be observed at relatively slow intended rhythmic movements. In view of the Hopf bifurcation underlying the limit cycle oscillator model, this observation suggests that the intended limit cycle movements were actually more similar to trajectories of a randomly perturbed stable focus. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
International Nuclear Information System (INIS)
Moog, Helge C.; Regenspurg, Simona; Voigt, Wolfgang
2015-02-01
The concept for geothermal energy application for electricity generation can be differentiated into three compartments: In the geologic compartment cooled fluid is pressed into a porous or fractured rock formation, in the borehole compartment a hot fluid is pumped to the surface and back into the geothermal reservoir, in the aboveground facility the energy is extracted from the geothermal fluid by heat exchangers. Pressure and temperature changes influence the thermodynamic equilibrium of a system. The modeling of a geothermal system has therefore to consider besides the mass transport the heat transport and consequently changing solution compositions and the pressure/temperature effected chemical equilibrium. The GEODAT project is aimed to simulate the reactive mass transport in a geothermal reservoir in the North German basin (Gross Schoenebeck). The project was performed by the cooperation of three partners: Geoforschungsinstitut Potsdam, Bergakademie Freiberg and GRS.
Grossman, B.; Garrett, J.; Cinnella, P.
1989-01-01
Several versions of flux-vector split and flux-difference split algorithms were compared with regard to general applicability and complexity. Test computations were performed using curve-fit equilibrium air chemistry for an M = 5 high-temperature inviscid flow over a wedge, and an M = 24.5 inviscid flow over a blunt cylinder for test computations; for these cases, little difference in accuracy was found among the versions of the same flux-split algorithm. For flows with nonequilibrium chemistry, the effects of the thermodynamic model on the development of flux-vector split and flux-difference split algorithms were investigated using an equilibrium model, a general nonequilibrium model, and a simplified model based on vibrational relaxation. Several numerical examples are presented, including nonequilibrium air chemistry in a high-temperature shock tube and nonequilibrium hydrogen-air chemistry in a supersonic diffuser.
SOLGAS refined: A computerized thermodynamic equilibrium calculation tool
Energy Technology Data Exchange (ETDEWEB)
Trowbridge, L.D.; Leitnaker, J.M.
1993-11-01
SOLGAS, an early computer program for calculating equilibrium in a chemical system, has been made more user-friendly, and several{open_quote} bells and whistles{close_quotes} have been added. The necessity to include elemental species has been eliminated. The input of large numbers of starting conditions has been automated. A revised format for entering data simplifies and reduces chances for error. Calculated errors by SOLGAS are flagged, and several programming errors are corrected. Auxiliary programs are available to assemble and partially automate plotting of large amounts of data. Thermodynamic input data can be changed {open_quotes}on line.{close_quote} The program can be operated with or without a co-processor. Copies of the program, suitable for the IBM-PC or compatible with at least 384 bytes of low RAM, are available from the authors.
Thermodynamic Equilibrium Calculations on Cd Transformation during Sewage Sludge Incineration.
Liu, Jing-yong; Huang, Limao; Sun, Shuiyu; Ning, Xun'an; Kuo, Jiahong; Sun, Jian; Wang, Yujie; Xie, Wuming
2016-06-01
Thermodynamic equilibrium calculations were performed to reveal the distribution of cadmium during the sewage sludge incineration process. During sludge incineration in the presence of major minerals, such as SiO2, Al2O3 and CaO, the strongest effect was exerted by SiO2 on the Cd transformation compared with the effect of others. The stable solid product of CdSiO3 was formed easily with the reaction between Cd and SiO2, which can restrain the emissions of gaseous Cd pollutants. CdCl2 was formed more easily in the presence of chloride during incineration, thus, the volatilization of Cd was advanced by increasing chlorine content. At low temperatures, the volatilization of Cd was restrained due to the formation of the refractory solid metal sulfate. At high temperatures, the speciation of Cd was not affected by the presence of sulfur, but sulfur could affect the formation temperature of gaseous metals.
SOLGAS refined: A computerized thermodynamic equilibrium calculation tool
International Nuclear Information System (INIS)
Trowbridge, L.D.; Leitnaker, J.M.
1993-11-01
SOLGAS, an early computer program for calculating equilibrium in a chemical system, has been made more user-friendly, and several open-quote bells and whistlesclose quotes have been added. The necessity to include elemental species has been eliminated. The input of large numbers of starting conditions has been automated. A revised format for entering data simplifies and reduces chances for error. Calculated errors by SOLGAS are flagged, and several programming errors are corrected. Auxiliary programs are available to assemble and partially automate plotting of large amounts of data. Thermodynamic input data can be changed open-quotes on line.close-quote The program can be operated with or without a co-processor. Copies of the program, suitable for the IBM-PC or compatible with at least 384 bytes of low RAM, are available from the authors
Application of constrained equilibrium thermodynamics to irradiated alloy systems
Holloway, James Paul; Stubbins, James F.
1984-05-01
Equilibrium thermodynamics are applied to systems with an excess of point defects to calculate the relative stability of phases. It is possible to model systems with supersaturation levels of vacancies and interstitials, such as those found under irradiation. The calculations reveal the extent to which phase compositional boundaries could shift when one phase or both in a two phase system contain an excess of point defects. Phase boundary shifts in the Ni-Si, Fe-Ni, Ni-Cr, and Fe-Cr systems are examined as a function of the number of excess defects in each phase. It is also found that the critical temperature of the sigma phase in the Fe-Cr system and the fcc-bcc transition in the Fe-Ni are sensitive to excess defect concentrations. These results may apply to local irradiation-induced phase transformations in the presence of solute segregation.
Equilibrium sampling for a thermodynamic assessment of contaminated sediments
DEFF Research Database (Denmark)
Mayer, Philipp; Nørgaard Schmidt, Stine; Mäenpää, Kimmo
Hydrophobic organic contaminants (HOCs) reaching the aquatic environment are largely stored in sediments. The risk of contaminated sediments is challenging to assess since traditional exhaustive extraction methods yield total HOC concentrations, whereas freely dissolved concentrations (Cfree......) govern diffusive uptake and partitioning. Equilibrium sampling of sediment was introduced 15 years ago to measure Cfree, and it has since developed into a straightforward, precise and sensitive approach for determining Cfree and other exposure parameters that allow for thermodynamic assessment...... of polluted sediments. Glass jars with µm-thin silicone coatings on the inner walls can be used for ex situ equilibration while a device housing several silicone-coated fibers can be used for in situ equilibration. In both cases, parallel sampling with varying silicone thicknesses can be applied to confirm...
Thermodynamical properties of dark energy
International Nuclear Information System (INIS)
Gong Yungui; Wang Bin; Wang Anzhong
2007-01-01
We have investigated the thermodynamical properties of dark energy. Assuming that the dark energy temperature T∼a -n and considering that the volume of the Universe enveloped by the apparent horizon relates to the temperature, we have derived the dark energy entropy. For dark energy with constant equation of state w>-1 and the generalized Chaplygin gas, the derived entropy can be positive and satisfy the entropy bound. The total entropy, including those of dark energy, the thermal radiation, and the apparent horizon, satisfies the generalized second law of thermodynamics. However, for the phantom with constant equation of state, the positivity of entropy, the entropy bound, and the generalized second law cannot be satisfied simultaneously
Chang, Yingju; Lai, Juin-Yih; Lee, Duu-Jong
2016-12-01
The standard Gibbs free energy, enthalpy and entropy change data for adsorption equilibrium reported in biosorption literature during January 2013-May2016 were listed. Since the studied biosorption systems are all near-equilibrium processes, the enthalpy and entropy change data evaluated by fitting temperature-dependent free energy data using van Hoff's equation reveal a compensation artifact. Additional confusion is introduced with arbitrarily chosen adsorbate concentration unit in bulk solution that added free energy change of mixing into the reported free energy and enthalpy change data. Different standard states may be chosen for properly describing biosorption processes; however, this makes the general comparison between data from different systems inappropriate. No conclusion should be drawn based on unjustified thermodynamic parameters reported in biosorption studies. Copyright © 2016 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Kantasamy, N.; Siti Mariam Sumari
2016-01-01
Adsorption isotherm describes the interaction of adsorbates with adsorbent in equilibrium. Equilibrium data was examined using Langmuir and Freundlich isotherm models. Thermodynamic studies were used to evaluate the thermodynamic parameters; heat of enthalpy change (ΔH degree), Gibbs free energy change (ΔG degree) and heat of entropy change (ΔSdegree) in order to gain information regarding the nature of adsorption (exothermic or endothermic). Four reactive dyes of anionic type, Acid Blue 29 (AB29), Reactive Black 5 (RB5), Reactive Orange 16 (RO16) and Reactive Red 120 (RR120) were used to obtain equilibrium isotherms at 25, 35, 45 and 55 degree Celsius. Based on Giles' classification, the isotherm produced were of L2-type, indicating strong dye affinity towards the adsorbent, and with weak competition with the solvent molecules for active adsorption sites. Equilibrium data fitted both Langmuir and Freundlich isotherm models with high correlation coefficient (R"2 > 0.91) indicating the possibility of both homogeneity and heterogeneous nature of adsorption. The negative values of ΔGdegree indicate the adsorption processes were spontaneous and feasible. The negative values of ΔHdegree lie between -20 to -75 kJ/ mol, suggesting these processes were exothermic and physical in nature. The negative values of ΔSdegree are indication of decreased disorder and randomness of spontaneous adsorption of reactive dyes on layered double hydroxide as adsorbent. (author)
International Nuclear Information System (INIS)
Louis-Martinez, Domingo J
2011-01-01
A classical (non-quantum-mechanical) relativistic ideal gas in thermodynamic equilibrium in a uniformly accelerated frame of reference is studied using Gibbs's microcanonical and grand canonical formulations of statistical mechanics. Using these methods explicit expressions for the particle, energy and entropy density distributions are obtained, which are found to be in agreement with the well-known results of the relativistic formulation of Boltzmann's kinetic theory. Explicit expressions for the total entropy, total energy and rest mass of the gas are obtained. The position of the center of mass of the gas in equilibrium is found. The non-relativistic and ultrarelativistic approximations are also considered. The phase space volume of the system is calculated explicitly in the ultrarelativistic approximation.
Local thermodynamic equilibrium considerations in powerchip laser-induced plasmas
Energy Technology Data Exchange (ETDEWEB)
Merten, Jonathan A., E-mail: jmerten@astate.edu; Smith, Benjamin W., E-mail: bwsmith@chem.ufl.edu; Omenetto, Nicoló, E-mail: omenetto@chem.ufl.edu
2013-05-01
Time-resolved emission experiments are reported in the fast-decaying transient plasma induced by a microchip laser on an aluminum target in three different cover gases, i.e., air, argon and helium. The laser operates at 532 nm, with a repetition frequency of 1 kHz and a pulse width of less than 0.5 ns. The overall persistence of plasma emission is of the order of 100 ns. We examine the existence of local thermodynamic equilibrium (LTE) by evaluating the temporal criteria required (in addition to the McWhirter criterion), as recommended by Cristoforetti et al. (Spectrochim. Acta Part B 65, 2010, 86–95). The temporal criteria examine the evolution of temperature and electron number density and compare their rate of change to the rate at which electron collisions can thermalize the change. These considerations are used to determine time windows in which LTE may be present. Our results suggest that calibration-free LIBS measurements with these lasers may be possible for some elements at early times, especially under argon. - Highlights: ► Powerchip laser-induced plasma evolution is affected by cover gas. ► Plasma often out of LTE, despite fulfilling the McWhirter criterion ► Calibration-free LIBS may be possible with powerchip laser plasmas.
Local thermodynamic equilibrium considerations in powerchip laser-induced plasmas
International Nuclear Information System (INIS)
Merten, Jonathan A.; Smith, Benjamin W.; Omenetto, Nicoló
2013-01-01
Time-resolved emission experiments are reported in the fast-decaying transient plasma induced by a microchip laser on an aluminum target in three different cover gases, i.e., air, argon and helium. The laser operates at 532 nm, with a repetition frequency of 1 kHz and a pulse width of less than 0.5 ns. The overall persistence of plasma emission is of the order of 100 ns. We examine the existence of local thermodynamic equilibrium (LTE) by evaluating the temporal criteria required (in addition to the McWhirter criterion), as recommended by Cristoforetti et al. (Spectrochim. Acta Part B 65, 2010, 86–95). The temporal criteria examine the evolution of temperature and electron number density and compare their rate of change to the rate at which electron collisions can thermalize the change. These considerations are used to determine time windows in which LTE may be present. Our results suggest that calibration-free LIBS measurements with these lasers may be possible for some elements at early times, especially under argon. - Highlights: ► Powerchip laser-induced plasma evolution is affected by cover gas. ► Plasma often out of LTE, despite fulfilling the McWhirter criterion ► Calibration-free LIBS may be possible with powerchip laser plasmas
Non-equilibrium statistical thermodynamics of neutron gas in reactor
International Nuclear Information System (INIS)
Hayasaka, Hideo
1977-01-01
The thermodynamic structures of non-equilibrium steady states of highly rarefied neutron gas in various media are considered for the irreversible processes owing to creative and destructive reactions of neutrons with nuclei of these media and supply from the external sources. Under the so-called clean and cold condition in reactor, the medium is regarded virtually as offering the different chemical potential fields for each subsystem of a steady neutron gas system. The fluctuations around a steady state are considered in a Markovian-Gaussian process. The generalized Einstein relations are derived for stationary neutron gas systems. The forces and flows of neutron gases in a medium are defined upon the general stationary solution of the Fokker-Planck equation. There exist the symmetry of the kinetic coefficients, and the minimum entropy production upon neutron-nuclear reactions. The distribution functions in various media are determined by each corresponding extremum condition under the vanishing of changes of the respective total entropies in the Gibbs equation. (auth.)
Calculating zeros: Non-equilibrium free energy calculations
International Nuclear Information System (INIS)
Oostenbrink, Chris; Gunsteren, Wilfred F. van
2006-01-01
Free energy calculations on three model processes with theoretically known free energy changes have been performed using short simulation times. A comparison between equilibrium (thermodynamic integration) and non-equilibrium (fast growth) methods has been made in order to assess the accuracy and precision of these methods. The three processes have been chosen to represent processes often observed in biomolecular free energy calculations. They involve a redistribution of charges, the creation and annihilation of neutral particles and conformational changes. At very short overall simulation times, the thermodynamic integration approach using discrete steps is most accurate. More importantly, reasonable accuracy can be obtained using this method which seems independent of the overall simulation time. In cases where slow conformational changes play a role, fast growth simulations might have an advantage over discrete thermodynamic integration where sufficient sampling needs to be obtained at every λ-point, but only if the initial conformations do properly represent an equilibrium ensemble. From these three test cases practical lessons can be learned that will be applicable to biomolecular free energy calculations
A redefinition of Hawking temperature on the event horizon: Thermodynamical equilibrium
International Nuclear Information System (INIS)
Saha, Subhajit; Chakraborty, Subenoy
2012-01-01
In this Letter we have used the recently introduced redefined Hawking temperature on the event horizon and investigated whether the generalized second law of thermodynamics (GSLT) and thermodynamic equilibrium holds for both the event and the apparent horizons. Here we have considered FRW universe and examined the GSLT and thermodynamic equilibrium with three examples. Finally, we have concluded that from the thermodynamic viewpoint, the universe bounded by the event horizon is more realistic than that by the apparent horizon at least for some examples.
International Nuclear Information System (INIS)
Hayasaka, Hideo
1978-01-01
The thermodynamic structures of non-equilibrium steady states of a highly rarefied neutron gas in various media are considered in terms of the irreversible processes due to creative and destructive reactions of neutrons with nuclei of these media and to neutrons supplied from external sources. The respective subsystems of the stationary neutron gas are regarded as imperfect equilibrium systems in the presence of the medium and the external neutron sources, and are treated like different species in a mixture. The entropy production due to neutron-nuclear reactions has a minimum value at the steady state. The distribution function of such a neutron gas is determined from the extremum condition in which entropy does not change, and is expressed as a shifted Boltzmann distribution specified by the respective values of the generalized chemical potential for each energy level. (author)
International Nuclear Information System (INIS)
Zaghloul, Mofreh R.
2003-01-01
Flibe (2LiF-BeF2) is a molten salt that has been chosen as the coolant and breeding material in many design studies of the inertial confinement fusion (ICF) chamber. Flibe plasmas are to be generated in the ICF chamber in a wide range of temperatures and densities. These plasmas are more complex than the plasma of any single chemical species. Nevertheless, the composition and thermodynamic properties of the resulting flibe plasmas are needed for the gas dynamics calculations and the determination of other design parameters in the ICF chamber. In this paper, a simple consistent model for determining the detailed plasma composition and thermodynamic functions of high-temperature, fully dissociated and partially ionized flibe gas is presented and used to calculate different thermodynamic properties of interest to fusion applications. The computed properties include the average ionization state; kinetic pressure; internal energy; specific heats; adiabatic exponent, as well as the sound speed. The presented results are computed under the assumptions of local thermodynamic equilibrium (LTE) and electro-neutrality. A criterion for the validity of the LTE assumption is presented and applied to the computed results. Other attempts in the literature are assessed with their implied inaccuracies pointed out and discussed
Experimental determination of thermodynamic equilibrium in biocatalytic transamination
DEFF Research Database (Denmark)
Tufvesson, Pär; Jensen, Jacob Skibsted; Kroutil, Wolfgang
2012-01-01
The equilibrium constant is a critical parameter for making rational design choices in biocatalytic transamination for the synthesis of chiral amines. However, very few reports are available in the scientific literature determining the equilibrium constant (K) for the transamination of ketones....... Various methods for determining (or estimating) equilibrium have previously been suggested, both experimental as well as computational (based on group contribution methods). However, none of these were found suitable for determining the equilibrium constant for the transamination of ketones. Therefore...
Non-equilibrium thermodynamics of radiation-induced processes in solids
International Nuclear Information System (INIS)
Yurov, V.M.; Eshchanov, A.N.; Kuketaev, A.T.; Sidorenya, Yu.S.
2005-01-01
In the paper an item about a defect system response in solids on external action (temperature, pressure, light, etc.) from the point of view of non-equilibrium statistical thermodynamics is considered
Studies on the formulation of thermodynamics and stochastic theory for systems far from equilibrium
Energy Technology Data Exchange (ETDEWEB)
Ross, J. [Stanford Univ., CA (United States)
1995-12-31
We have been working for some time on the formulation of thermodynamics and the theory of fluctuations in systems far from equilibrium and progress in several aspects of that development are reported here.
International Nuclear Information System (INIS)
Shchukina, N.G.
1980-01-01
The methodology of the problem of deviation from local thermodynamical equilibrium in the solar atmosphere is presented. The difficulties of solution and methods of realization are systematized. The processes of line formation are considered which take into account velocity fields, structural inhomogeneity, radiation non-coherence etc. as applied to a quiet solar atmosphere. The conclusion is made on the regularity of deviation of the local thermodynamic equilibrium in upper layers of the solar atmosphere
Non-equilibrium thermodynamics, maximum entropy production and Earth-system evolution.
Kleidon, Axel
2010-01-13
The present-day atmosphere is in a unique state far from thermodynamic equilibrium. This uniqueness is for instance reflected in the high concentration of molecular oxygen and the low relative humidity in the atmosphere. Given that the concentration of atmospheric oxygen has likely increased throughout Earth-system history, we can ask whether this trend can be generalized to a trend of Earth-system evolution that is directed away from thermodynamic equilibrium, why we would expect such a trend to take place and what it would imply for Earth-system evolution as a whole. The justification for such a trend could be found in the proposed general principle of maximum entropy production (MEP), which states that non-equilibrium thermodynamic systems maintain steady states at which entropy production is maximized. Here, I justify and demonstrate this application of MEP to the Earth at the planetary scale. I first describe the non-equilibrium thermodynamic nature of Earth-system processes and distinguish processes that drive the system's state away from equilibrium from those that are directed towards equilibrium. I formulate the interactions among these processes from a thermodynamic perspective and then connect them to a holistic view of the planetary thermodynamic state of the Earth system. In conclusion, non-equilibrium thermodynamics and MEP have the potential to provide a simple and holistic theory of Earth-system functioning. This theory can be used to derive overall evolutionary trends of the Earth's past, identify the role that life plays in driving thermodynamic states far from equilibrium, identify habitability in other planetary environments and evaluate human impacts on Earth-system functioning. This journal is © 2010 The Royal Society
Decay to Equilibrium for Energy-Reaction-Diffusion Systems
Haskovec, Jan
2018-02-06
We derive thermodynamically consistent models of reaction-diffusion equations coupled to a heat equation. While the total energy is conserved, the total entropy serves as a driving functional such that the full coupled system is a gradient flow. The novelty of the approach is the Onsager structure, which is the dual form of a gradient system, and the formulation in terms of the densities and the internal energy. In these variables it is possible to assume that the entropy density is strictly concave such that there is a unique maximizer (thermodynamical equilibrium) given linear constraints on the total energy and suitable density constraints. We consider two particular systems of this type, namely, a diffusion-reaction bipolar energy transport system, and a drift-diffusion-reaction energy transport system with confining potential. We prove corresponding entropy-entropy production inequalities with explicitly calculable constants and establish the convergence to thermodynamical equilibrium, first in entropy and later in L norm using Cziszár–Kullback–Pinsker type inequalities.
Decay to Equilibrium for Energy-Reaction-Diffusion Systems
Haskovec, Jan; Hittmeir, Sabine; Markowich, Peter A.; Mielke, Alexander
2018-01-01
We derive thermodynamically consistent models of reaction-diffusion equations coupled to a heat equation. While the total energy is conserved, the total entropy serves as a driving functional such that the full coupled system is a gradient flow. The novelty of the approach is the Onsager structure, which is the dual form of a gradient system, and the formulation in terms of the densities and the internal energy. In these variables it is possible to assume that the entropy density is strictly concave such that there is a unique maximizer (thermodynamical equilibrium) given linear constraints on the total energy and suitable density constraints. We consider two particular systems of this type, namely, a diffusion-reaction bipolar energy transport system, and a drift-diffusion-reaction energy transport system with confining potential. We prove corresponding entropy-entropy production inequalities with explicitly calculable constants and establish the convergence to thermodynamical equilibrium, first in entropy and later in L norm using Cziszár–Kullback–Pinsker type inequalities.
International Nuclear Information System (INIS)
Hongxia Zhang; Zhiwei Niu; Zhi Liu; Zhaodong Wen; Weiping Li; Xiaoyun Wang; Wangsuo Wu
2015-01-01
The kinetics and thermodynamics of the adsorption of Th(IV) on the kaolin were studied by using batch method. In addition, the experimental data were studied by dynamic and thermodynamic models. The results showed that the adsorption capacity of the adsorbent increased with increasing temperature and solid liquid ratio, but decreased with increasing initial Th(IV) ion concentration, and the best fit was obtained for the pseudo-second-order kinetics model. The calculated activation energy for adsorption was about 45 kJ/mol, which indicated the adsorption process to be chemisorption. The adsorption isotherm data could be well described by the Langmuir as well as Dubinin-Radushkevich model. The mean free energy (E) of adsorption was calculated to be about 15 kJ/mol. The thermodynamic data calculated showed that the adsorption was spontaneous and enhanced at higher temperature. Considering kinetics and equilibrium studies, the adsorption on the sites was the rate-limiting step and that adsorption was mainly a chemisorption process through cation exchange. (author)
A Unified Graphical Representation of Chemical Thermodynamics and Equilibrium
Hanson, Robert M.
2012-01-01
During the years 1873-1879, J. Willard Gibbs published his now-famous set of articles that form the basis of the current perspective on chemical thermodynamics. The second article of this series, "A Method of Geometrical Representation of the Thermodynamic Properties of Substances by Means of Surfaces," published in 1873, is particularly notable…
The thermodynamic solar energy; Le solaire thermodynamique
Energy Technology Data Exchange (ETDEWEB)
Rivoire, B. [Centre National de la Recherche Scientifique (CNRS-IMP), 66 - Perpignan (France)
2002-04-01
The thermodynamic solar energy is the technic in the whole aiming to transform the solar radiation energy in high temperature heat and then in mechanical energy by a thermodynamic cycle. These technic are most often at an experimental scale. This paper describes and analyzes the research programs developed in the advanced countries, since 1980. (A.L.B.)
Saha, Subhajit; Biswas, Atreyee; Chakraborty, Subenoy
2015-01-01
In the present work, flat FRW model of the universe is considered to be an isolated open thermodynamical system where non-equilibrium prescription has been studied using the mechanism of particle creation. In the perspective of recent observational evidences, the matter distribution in the universe is assumed to be dominated by dark matter and dark energy. The dark matter is chosen as dust while for dark energy, the following choices are considered: (i) Perfect fluid with constant equation of...
Equilibrium thermodynamics and neutrino decoupling in quasi-metric cosmology
Østvang, Dag
2018-05-01
The laws of thermodynamics in the expanding universe are formulated within the quasi-metric framework. The quasi-metric cosmic expansion does not directly influence momenta of material particles, so the expansion directly cools null particles only (e.g., photons). Therefore, said laws differ substantially from their counterparts in standard cosmology. Consequently, all non-null neutrino mass eigenstates are predicted to have the same energy today as they had just after neutrino decoupling in the early universe. This indicates that the predicted relic neutrino background is strongly inconsistent with detection rates measured in solar neutrino detectors (Borexino in particular). Thus quasi-metric cosmology is in violent conflict with experiment unless some exotic property of neutrinos makes the relic neutrino background essentially undetectable (e.g., if all massive mass eigenstates decay into "invisible" particles over cosmic time scales). But in absence of hard evidence in favour of the necessary exotic neutrino physics needed to resolve said conflict, the current status of quasi-metric relativity has been changed to non-viable.
Coherent application of a contact structure to formulate Classical Non-Equilibrium Thermodynamics
Knobbe, E; Roekaerts, D.J.E.M.
2017-01-01
This contribution presents an outline of a new mathematical formulation for
Classical Non-Equilibrium Thermodynamics (CNET) based on a contact
structure in differential geometry. First a non-equilibrium state space is introduced as the third key element besides the first and second law of
The Donnan equilibrium: I. On the thermodynamic foundation of the Donnan equation of state
Philipse, A.P.; Vrij, A.
2011-01-01
The thermodynamic equilibrium between charged colloids and an electrolyte reservoir is named after Frederic Donnan who first published on it one century ago (Donnan 1911 Z. Electrochem. 17 572). One of the intriguing features of the Donnan equilibrium is the ensuing osmotic equation of state which
Non-Equilibrium Properties from Equilibrium Free Energy Calculations
Pohorille, Andrew; Wilson, Michael A.
2012-01-01
Calculating free energy in computer simulations is of central importance in statistical mechanics of condensed media and its applications to chemistry and biology not only because it is the most comprehensive and informative quantity that characterizes the eqUilibrium state, but also because it often provides an efficient route to access dynamic and kinetic properties of a system. Most of applications of equilibrium free energy calculations to non-equilibrium processes rely on a description in which a molecule or an ion diffuses in the potential of mean force. In general case this description is a simplification, but it might be satisfactorily accurate in many instances of practical interest. This hypothesis has been tested in the example of the electrodiffusion equation . Conductance of model ion channels has been calculated directly through counting the number of ion crossing events observed during long molecular dynamics simulations and has been compared with the conductance obtained from solving the generalized Nernst-Plank equation. It has been shown that under relatively modest conditions the agreement between these two approaches is excellent, thus demonstrating the assumptions underlying the diffusion equation are fulfilled. Under these conditions the electrodiffusion equation provides an efficient approach to calculating the full voltage-current dependence routinely measured in electrophysiological experiments.
Thermodynamical inequivalence of quantum stress-energy and spin tensors
International Nuclear Information System (INIS)
Becattini, F.; Tinti, L.
2011-01-01
It is shown that different couples of stress-energy and spin tensors of quantum-relativistic fields, which would be otherwise equivalent, are in fact inequivalent if the second law of thermodynamics is taken into account. The proof of the inequivalence is based on the analysis of a macroscopic system at full thermodynamical equilibrium with a macroscopic total angular momentum and a specific instance is given for the free Dirac field, for which we show that the canonical and Belinfante stress-energy tensors are not equivalent. For this particular case, we show that the difference between the predicted angular momentum densities for a rotating system at full thermodynamical equilibrium is a quantum effect, persisting in the nonrelativistic limit, corresponding to a polarization of particles of the order of (ℎ/2π)ω/KT (ω being the angular velocity) and could in principle be measured experimentally. This result implies that specific stress-energy and spin tensors are physically meaningful even in the absence of gravitational coupling and raises the issue of finding the thermodynamically right (or the right class of) tensors. We argue that the maximization of the thermodynamic potential theoretically allows us to discriminate between two different couples, yet for the present we are unable to provide a theoretical method to single out the best couple of tensors in a given quantum field theory. The existence of a nonvanishing spin tensor would have major consequences in hydrodynamics, gravity and cosmology.
Equilibrium fluctuation energy of gyrokinetic plasma
International Nuclear Information System (INIS)
Krommes, J.A.; Lee, W.W.; Oberman, C.
1985-11-01
The thermal equilibrium electric field fluctuation energy of the gyrokinetic model of magnetized plasma is computed, and found to be smaller than the well-known result (k)/8π = 1/2T/[1 + (klambda/sub D/) 2 ] valid for arbitrarily magnetized plasmas. It is shown that, in a certain sense, the equilibrium electric field energy is minimum in the gyrokinetic regime. 13 refs., 2 figs
Thermodynamics for scientists and engineers
International Nuclear Information System (INIS)
Lim, Gyeong Hui
2011-02-01
This book deals with thermodynamics for scientists and engineers. It consists of 11 chapters, which are concept and background of thermodynamics, the first law of thermodynamics, the second law of thermodynamics and entropy, mathematics related thermodynamics, properties of thermodynamics on pure material, equilibrium, stability of thermodynamics, the basic of compound, phase equilibrium of compound, excess gibbs energy model of compound and activity coefficient model and chemical equilibrium. It has four appendixes on properties of pure materials and thermal mass.
Vapor-liquid equilibrium thermodynamics of N2 + CH4 - Model and Titan applications
Thompson, W. R.; Zollweg, John A.; Gabis, David H.
1992-01-01
A thermodynamic model is presented for vapor-liquid equilibrium in the N2 + CH4 system, which is implicated in calculations of the Titan tropospheric clouds' vapor-liquid equilibrium thermodynamics. This model imposes constraints on the consistency of experimental equilibrium data, and embodies temperature effects by encompassing enthalpy data; it readily calculates the saturation criteria, condensate composition, and latent heat for a given pressure-temperature profile of the Titan atmosphere. The N2 content of condensate is about half of that computed from Raoult's law, and about 30 percent greater than that computed from Henry's law.
Thermodynamic quantities and defect equilibrium in La2-xSrxNiO4+δ
International Nuclear Information System (INIS)
Nakamura, Takashi; Yashiro, Keiji; Sato, Kazuhisa; Mizusaki, Junichiro
2009-01-01
In order to elucidate the relation between thermodynamic quantities, the defect structure, and the defect equilibrium in La 2-x Sr x NiO 4+δ , statistical thermodynamic calculation is carried out and calculated results are compared to those obtained from experimental data. Partial molar enthalpy of oxygen and partial molar entropy of oxygen are obtained from δ-P(O 2 )-T relation by using Gibbs-Helmholtz equation. Statistical thermodynamic model is derived from defect equilibrium models proposed before by authors, localized electron model and delocalized electron model which could well explain the variation of oxygen content of La 2-x Sr x NiO 4+δ . Although assumed defect species and their equilibrium are different, the results of thermodynamic calculation by localized electron model and delocalized electron model show minor difference. Calculated results by the both models agree with the thermodynamic quantities obtained from oxygen nonstoichiometry of La 2-x Sr x NiO 4+δ . - Graphical abstract: In order to elucidate the relation between thermodynamic quantities, the defect structure, and the defect equilibrium in La 2-x Sr x NiO 4+δ , statistics thermodynamic calculation is carried out and calculated results are compared to those obtained from experimental data.
Chapman, Brian
2017-06-01
This paper seeks to develop a more thermodynamically sound pedagogy for students of biological transport than is currently available from either of the competing schools of linear non-equilibrium thermodynamics (LNET) or Michaelis-Menten kinetics (MMK). To this end, a minimal model of facilitated diffusion was constructed comprising four reversible steps: cis- substrate binding, cis → trans bound enzyme shuttling, trans -substrate dissociation and trans → cis free enzyme shuttling. All model parameters were subject to the second law constraint of the probability isotherm, which determined the unidirectional and net rates for each step and for the overall reaction through the law of mass action. Rapid equilibration scenarios require sensitive 'tuning' of the thermodynamic binding parameters to the equilibrium substrate concentration. All non-equilibrium scenarios show sigmoidal force-flux relations, with only a minority of cases having their quasi -linear portions close to equilibrium. Few cases fulfil the expectations of MMK relating reaction rates to enzyme saturation. This new approach illuminates and extends the concept of rate-limiting steps by focusing on the free energy dissipation associated with each reaction step and thereby deducing its respective relative chemical impedance. The crucial importance of an enzyme's being thermodynamically 'tuned' to its particular task, dependent on the cis- and trans- substrate concentrations with which it deals, is consistent with the occurrence of numerous isoforms for enzymes that transport a given substrate in physiologically different circumstances. This approach to kinetic modelling, being aligned with neither MMK nor LNET, is best described as intuitive non-equilibrium thermodynamics, and is recommended as a useful adjunct to the design and interpretation of experiments in biotransport.
Horowitz, Jordan M
2015-07-28
The stochastic thermodynamics of a dilute, well-stirred mixture of chemically reacting species is built on the stochastic trajectories of reaction events obtained from the chemical master equation. However, when the molecular populations are large, the discrete chemical master equation can be approximated with a continuous diffusion process, like the chemical Langevin equation or low noise approximation. In this paper, we investigate to what extent these diffusion approximations inherit the stochastic thermodynamics of the chemical master equation. We find that a stochastic-thermodynamic description is only valid at a detailed-balanced, equilibrium steady state. Away from equilibrium, where there is no consistent stochastic thermodynamics, we show that one can still use the diffusive solutions to approximate the underlying thermodynamics of the chemical master equation.
thermodynamics of ion exchange equilibrium for some uni
African Journals Online (AJOL)
a
equilibrium studies [9-30], extending over a wide range of composition of solution and ... by dissolving their corresponding potassium salts (Analytical grade) in distilled ... calculated from which average value of K for that set of experiment was ...
Lebon, G.; Jou, D.
2015-06-01
This paper gives a historical account of the early years (1953-1983) of extended irreversible thermodynamics (EIT). The salient features of this formalism are to upgrade the thermodynamic fluxes of mass, momentum, energy, and others, to the status of independent variables, and to explore the consistency between generalized transport equations and a generalized version of the second law of thermodynamics. This requires going beyond classical irreversible thermodynamics by redefining entropy and entropy flux. EIT provides deeper foundations, closer relations with microscopic formalisms, a wider spectrum of applications, and a more exciting conceptual appeal to non-equilibrium thermodynamics. We first recall the historical contributions by Maxwell, Cattaneo, and Grad on generalized transport equations. A thermodynamic theory wide enough to cope with such transport equations was independently proposed between 1953 and 1983 by several authors, each emphasizing different kinds of problems. In 1983, the first international meeting on this theory took place in Bellaterra (Barcelona). It provided the opportunity for the various authors to meet together for the first time and to discuss the common points and the specific differences of their previous formulations. From then on, a large amount of applications and theoretical confirmations have emerged. From the historical point of view, the emergence of EIT has been an opportunity to revisit the foundations and to open new avenues in thermodynamics, one of the most classical and well consolidated physical theories.
International Nuclear Information System (INIS)
Rincón, R.; Muñoz, J.; Calzada, M.D.
2015-01-01
Plasma torches are suitable plasma sources for a wide range of applications. The capability of these discharges to produce processes like sample excitation or decomposition of molecules inside them depends on the density of the plasma species and their energies (temperatures). The relation between these parameters determines the specific state of thermodynamic equilibrium in the discharge. Thus, the understanding of plasma possibilities for application purposes is related to the knowledge of the plasma thermodynamic equilibrium degree. In this paper a discussion about the equilibrium state for Ar plasmas generated by using a Torche à Injection Axiale sur Guide d'Ondes, TIAGO device, is presented. Emission spectroscopy techniques were used to measure gas temperature and electron density at the exit of the nozzle torch and along the dart. Boltzmann-plots as well as b p parameters were calculated to characterize the type and degree of departure from partial Local Saha Equilibrium (pLSE). This study indicates that the closer situation to Local Thermodynamic Equilibrium (LTE) of the plasma corresponds to larger Ar flows which highlights the importance of the nitrogen (atmosphere surrounding the plasma) in the kinetics of Ar-TIAGO discharges. - Highlights: • Discharges sustained in Ar using a TIAGO Torch show a significant departure from Local Thermodynamic Equilibrium. • Nitrogen entrance from surrounding air highly influences Thermodynamic Equilibrium. • Departure from LTE has been studied by means of Boltzmann plots and b p parameters. • The discharge is ionizing at the nozzle exit plasma, while along the dart it becomes recombining
Non local-thermodynamical-equilibrium effects in the simulation of laser-produced plasmas
Klapisch, M.; Bar-Shalom, A.; Oreg, J.; Colombant, D.
1998-05-01
Local thermodynamic equilibrium (LTE) breaks down in directly or indirectly driven laser plasmas because of sharp gradients, energy deposition, etc. For modeling non-LTE effects in hydrodynamical simulations, Busquet's model [Phys. Fluids B 5, 4191 (1993)] is very convenient and efficient. It uses off-line generated LTE opacities and equation of states via an effective, radiation-dependent ionization temperature Tz. An overview of the model is given. The results are compared with an elaborate collisional radiative model based on superconfigurations. The agreements for average charge Z* and opacities are surprisingly good, even more so when the plasma is immersed in a radiation field. Some remaining discrepancy at low density is attributed to dielectronic recombination. Improvement appears possible, especially for emissivities, because the concept of ionization temperature seems to be validated.
Non local-thermodynamical-equilibrium effects in the simulation of laser-produced plasmas
International Nuclear Information System (INIS)
Klapisch, M.; Bar-Shalom, A.; Oreg, J.; Colombant, D.
1998-01-01
Local thermodynamic equilibrium (LTE) breaks down in directly or indirectly driven laser plasmas because of sharp gradients, energy deposition, etc. For modeling non-LTE effects in hydrodynamical simulations, Busquet close-quote s model [Phys. Fluids B 5, 4191 (1993)] is very convenient and efficient. It uses off-line generated LTE opacities and equation of states via an effective, radiation-dependent ionization temperature T z . An overview of the model is given. The results are compared with an elaborate collisional radiative model based on superconfigurations. The agreements for average charge Z * and opacities are surprisingly good, even more so when the plasma is immersed in a radiation field. Some remaining discrepancy at low density is attributed to dielectronic recombination. Improvement appears possible, especially for emissivities, because the concept of ionization temperature seems to be validated. copyright 1998 American Institute of Physics
A non-equilibrium thermodynamic model for tumor extracellular matrix with enzymatic degradation
Xue, Shi-Lei; Li, Bo; Feng, Xi-Qiao; Gao, Huajian
2017-07-01
The extracellular matrix (ECM) of a solid tumor not only affords scaffolding to support tumor architecture and integrity but also plays an essential role in tumor growth, invasion, metastasis, and therapeutics. In this paper, a non-equilibrium thermodynamic theory is established to study the chemo-mechanical behaviors of tumor ECM, which is modeled as a poroelastic polyelectrolyte consisting of a collagen network and proteoglycans. By using the principle of maximum energy dissipation rate, we deduce a set of governing equations for drug transport and mechanosensitive enzymatic degradation in ECM. The results reveal that osmosis is primarily responsible for the compression resistance of ECM. It is suggested that a well-designed ECM degradation can effectively modify the tumor microenvironment for improved efficiency of cancer therapy. The theoretical predictions show a good agreement with relevant experimental observations. This study aimed to deepen our understanding of tumor ECM may be conducive to novel anticancer strategies.
Nanostructured energy devices equilibrium concepts and kinetics
Bisquert, Juan
2014-01-01
Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu
Thermodynamic formalism the mathematical structures of equilibrium statistical mechanics
Ruelle, David
2004-01-01
Reissued in the Cambridge Mathematical Library, this classic book outlines the theory of thermodynamic formalism which was developed to describe the properties of certain physical systems consisting of a large number of subunits. Background material on physics has been collected in appendices to help the reader. Supplementary work is provided in the form of exercises and problems that were "open" at the original time of writing.
Non-equilibrium Thermodynamics and the Production of Entropy Life, Earth, and Beyond
Kleidon, Axel
2005-01-01
The present volume studies the application of concepts from non-equilibrium thermodynamics to a variety of research topics. Emphasis is on the Maximum Entropy Production (MEP) principle and applications to Geosphere-Biosphere couplings. Written by leading researchers form a wide range of background, the book proposed to give a first coherent account of an emerging field at the interface of thermodynamics, geophysics and life sciences.
Nieuwenhuizen, T.M.
2001-01-01
Glass is an under-cooled liquid that very slowly relaxes towards the equilibrium crystalline state. Its energy balance is ill understood, since it is widely believed that the glassy state cannot be described thermodynamically. However, the classical paradoxes involving the Ehrenfest relations and
International Nuclear Information System (INIS)
Jang, Won-Jun; Jeong, Dae-Woon; Shim, Jae-Oh; Kim, Hak-Min; Roh, Hyun-Seog; Son, In Hyuk; Lee, Seung Jae
2016-01-01
Highlights: • Selected variables have a significant influence on yields of synthesis gas. • (CO_2 + H_2O)/CH_4 affects the temperature which can achieve the maximum conversion. • Coke is formed at low temperatures even with excess oxidizing agent. • The occurrence of RWGS becomes critical in real chemical reactions. • Equilibrium conversions are maintained for 500 h without detectable deactivation. - Abstract: Thermodynamic equilibrium analysis of the combined steam and carbon dioxide reforming of methane (CSCRM) and side reactions was performed using total Gibbs free energy minimization. The effects of (CO_2 + H_2O)/CH_4 ratio (0.9–2.9), CO_2:H_2O ratio (3:1–1:3), and temperature (500–1000 °C) on the equilibrium conversions, yields, coke yield, and H_2/CO ratio were investigated. A (CO_2 + H_2O)/CH_4 ratio greater than 1.2, a CO_2:H_2O ratio of 1:2.1, and a temperature of at least 850 °C are preferable reaction conditions for the synthesis gas preparation in the gas to liquid process. Simulated conditions were applied to the CSCRM reaction and the experimental data were compared with the thermodynamic equilibrium results. The thermodynamic equilibrium results were mostly consistent with the experimental data, but the reverse water gas shift reaction rapidly occurred in the real chemical reaction and under excess oxidizing agent conditions. In addition, a long-term stability test (under simulated conditions) showed that the equilibrium conversion was maintained for 500 h and that the coke formation on the used catalyst was not observed.
International Nuclear Information System (INIS)
Stout, R B
2001-01-01
A theoretical expression is developed for the dissolution rate response for multi-component radioactive materials that have surface adsorption kinetics and radiolysis kinetics when wetted by a multi-component aqueous solution. An application for this type of dissolution response is the performance evaluation of multi-component spent nuclear fuels (SNFs) for long term interim storage and for geological disposition. Typically, SNF compositions depend on initial composition, uranium oxide and metal alloys being most common, and on reactor burnup which results in a wide range of fission product and actinide concentrations that decay by alpha, beta, and gamma radiation. These compositional/burnup ranges of SNFs, whether placed in interim storage or emplaced in a geologic repository, will potentially be wetted by multi-component aqueous solutions, and these solutions may be further altered by radiolytic aqueous species due to three radiation fields. The solid states of the SNFs are not thermodynamically stable when wetted and will dissolve, with or without radiolysis. The following development of a dissolution theory is based on a non-equilibrium thermodynamic analysis of energy reactions and energy transport across a solid-liquid phase change discontinuity that propagates at a quasi-steady, dissolution velocity. The integral form of the energy balance equation is used for this spatial surface discontinuity analysis. The integral formulation contains internal energy functional of classical thermodynamics for both the SNFs' solid state and surface adsorption species, and the adjacent liquid state, which includes radiolytic chemical species. The steady-state concentrations of radiolytic chemical species are expressed by an approximate analysis of the decay radiation transport equation. For purposes of illustration a modified Temkin adsorption isotherm was assumed for the surface adsorption kinetics on an arbitrary, finite area of the solid-liquid dissolution interface. For
Calculation of thermodynamic equilibrium for reactions of plutonium with air
International Nuclear Information System (INIS)
Zou Lexi; Sun Ying; Luo Deli; Xue Weidong; Zhu Zhenghe; Wang Rong
2000-01-01
There are six independent component with 4 chemical elements, i.e. PuH 2.7 (s), PuN(s), Pu 2 O 3 (s), N 2 (g) and H 2 (g), therefore, the system described involves of 2 independent reactions, both ΔG degree << O. The mass balances calculated for gas and solid phases are in good agreement with those of experimental, indicating the chemical equilibrium is nearly approached. So, it is believed that the reaction ratio of plutonium hydride with air is extremely rapid. The results are meaningful to the storage of plutonium
Nonequilibrium thermodynamics and energy efficiency in weight loss diets
Directory of Open Access Journals (Sweden)
Fine Eugene J
2007-07-01
Full Text Available Abstract Carbohydrate restriction as a strategy for control of obesity is based on two effects: a behavioral effect, spontaneous reduction in caloric intake and a metabolic effect, an apparent reduction in energy efficiency, greater weight loss per calorie consumed. Variable energy efficiency is established in many contexts (hormonal imbalance, weight regain and knock-out experiments in animal models, but in the area of the effect of macronutrient composition on weight loss, controversy remains. Resistance to the idea comes from a perception that variable weight loss on isocaloric diets would somehow violate the laws of thermodynamics, that is, only caloric intake is important ("a calorie is a calorie". Previous explanations of how the phenomenon occurs, based on equilibrium thermodynamics, emphasized the inefficiencies introduced by substrate cycling and requirements for increased gluconeogenesis. Living systems, however, are maintained far from equilibrium, and metabolism is controlled by the regulation of the rates of enzymatic reactions. The principles of nonequilibrium thermodynamics which emphasize kinetic fluxes as well as thermodynamic forces should therefore also be considered. Here we review the principles of nonequilibrium thermodynamics and provide an approach to the problem of maintenance and change in body mass by recasting the problem of TAG accumulation and breakdown in the adipocyte in the language of nonequilibrium thermodynamics. We describe adipocyte physiology in terms of cycling between an efficient storage mode and a dissipative mode. Experimentally, this is measured in the rate of fatty acid flux and fatty acid oxidation. Hormonal levels controlled by changes in dietary carbohydrate regulate the relative contributions of the efficient and dissipative parts of the cycle. While no experiment exists that measures all relevant variables, the model is supported by evidence in the literature that 1 dietary carbohydrate, via its
Saha, Subhajit; Biswas, Atreyee; Chakraborty, Subenoy
2015-03-01
In the present work, flat FRW model of the universe is considered to be an isolated open thermodynamical system where non-equilibrium prescription has been studied using the mechanism of particle creation. In the perspective of recent observational evidences, the matter distribution in the universe is assumed to be dominated by dark matter and dark energy. The dark matter is chosen as dust while for dark energy, the following choices are considered: (i) Perfect fluid with constant equation of state and (ii) Holographic dark energy. In both the cases, the validity of generalized second law of thermodynamics (GSLT) which states that the total entropy of the fluid as well as that of the horizon should not decrease with the evolution of the universe, has been examined graphically for universe bounded by the event horizon. It is found that GSLT holds in both the cases with some restrictions on the interacting coupling parameter.
The Matrix model, a driven state variables approach to non-equilibrium thermodynamics
Jongschaap, R.J.J.
2001-01-01
One of the new approaches in non-equilibrium thermodynamics is the so-called matrix model of Jongschaap. In this paper some features of this model are discussed. We indicate the differences with the more common approach based upon internal variables and the more sophisticated Hamiltonian and GENERIC
An Easy and Effective Demonstration of Enzyme Stereospecificity and Equilibrium Thermodynamics
Herdman, Chelsea; Dickman, Michael
2011-01-01
Enzyme stereospecificity and equilibrium thermodynamics can be demonstrated using the coupling of two amino acid derivatives by Thermoase C160. This protease will catalyze peptide bond formation between Z-L-AspOH and L-PheOMe to form the Aspartame precursor Z-L-Asp-L-PheOMe. Reaction completion manifests itself by precipitation of the product. As…
Dilepton production from quark gluon plasma using non-equilibrium thermodynamics
International Nuclear Information System (INIS)
Sinha, B.
1984-01-01
The importance of the approach phase to the thermodynamic equilibrium has been investigated for dilepton production from quark-gluon plasma - an effective temperature for the quarks as Brounian particle in a heat bath of gluons has been suggested. The spectrum for low invariant mass is, as a consequence, sharper
Modelling non-equilibrium thermodynamic systems from the speed-gradient principle.
Khantuleva, Tatiana A; Shalymov, Dmitry S
2017-03-06
The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed.This article is part of the themed issue 'Horizons of cybernetical physics'. © 2017 The Author(s).
Thermodynamics of the multicomponent vapor-liquid equilibrium under capillary pressure difference
DEFF Research Database (Denmark)
Shapiro, Alexander; Stenby, Erling Halfdan
2001-01-01
We discuss the two-phase multicomponent equilibrium, provided that the phase pressures are different due to the action of capillary forces. We prove the two general properties of such an equilibrium, which have previously been known for a single-component case, however, to the best of our knowledge......, not for the multicomponent mixtures. The importance is emphasized on the space of the intensive variables P, T and mu (i), where the laws of capillary equilibrium have a simple geometrical interpretation. We formulate thermodynamic problems specific to such an equilibrium, and outline changes to be introduced to common...... algorithms of flash calculations in order to solve these problems. Sample calculations show large variation of the capillary properties of the mixture in the very neighborhood of the phase envelope and the restrictive role of the spinodal surface as a boundary for possible equilibrium states with different...
Entropy and energy quantization: Planck thermodynamic calculation
International Nuclear Information System (INIS)
Mota e Albuquerque, Ivone Freire da.
1988-01-01
This dissertation analyses the origins and development of the concept of entropy and its meaning of the second Law of thermodynamics, as well as the thermodynamics derivation of the energy quantization. The probabilistic interpretation of that law and its implication in physics theory are evidenciated. Based on Clausius work (which follows Carnot's work), we analyse and expose in a original way the entropy concept. Research upon Boltzmann's work and his probabilistic interpretation of the second Law of thermodynamics is made. The discuss between the atomistic and the energeticist points of view, which were actual at that time are also commented. (author). 38 refs., 3 figs
Directory of Open Access Journals (Sweden)
J. G. Dyke
2011-06-01
Full Text Available Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.
Jahnke, Annika; MacLeod, Matthew; Wickström, Håkan; Mayer, Philipp
2014-10-07
Equilibrium partitioning (EqP) theory is currently the most widely used approach for linking sediment pollution by persistent hydrophobic organic chemicals to bioaccumulation. Most applications of the EqP approach assume (I) a generic relationship between organic carbon-normalized chemical concentrations in sediments and lipid-normalized concentrations in biota and (II) that bioaccumulation does not induce levels exceeding those expected from equilibrium partitioning. Here, we demonstrate that assumption I can be obviated by equilibrating a silicone sampler with chemicals in sediment, measuring chemical concentrations in the silicone, and applying lipid/silicone partition ratios to yield concentrations in lipid at thermodynamic equilibrium with the sediment (CLip⇌Sed). Furthermore, we evaluated the validity of assumption II by comparing CLip⇌Sed of selected persistent, bioaccumulative and toxic pollutants (polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB)) to lipid-normalized concentrations for a range of biota from a Swedish background lake. PCBs in duck mussels, roach, eel, pikeperch, perch and pike were mostly below the equilibrium partitioning level relative to the sediment, i.e., lipid-normalized concentrations were ≤CLip⇌Sed, whereas HCB was near equilibrium between biota and sediment. Equilibrium sampling allows straightforward, sensitive and precise measurement of CLip⇌Sed. We propose CLip⇌Sed as a metric of the thermodynamic potential for bioaccumulation of persistent organic chemicals from sediment useful to prioritize management actions to remediate contaminated sites.
International Nuclear Information System (INIS)
Wu, Wei; Wang, Jin
2014-01-01
We have established a general non-equilibrium thermodynamic formalism consistently applicable to both spatially homogeneous and, more importantly, spatially inhomogeneous systems, governed by the Langevin and Fokker-Planck stochastic dynamics with multiple state transition mechanisms, using the potential-flux landscape framework as a bridge connecting stochastic dynamics with non-equilibrium thermodynamics. A set of non-equilibrium thermodynamic equations, quantifying the relations of the non-equilibrium entropy, entropy flow, entropy production, and other thermodynamic quantities, together with their specific expressions, is constructed from a set of dynamical decomposition equations associated with the potential-flux landscape framework. The flux velocity plays a pivotal role on both the dynamic and thermodynamic levels. On the dynamic level, it represents a dynamic force breaking detailed balance, entailing the dynamical decomposition equations. On the thermodynamic level, it represents a thermodynamic force generating entropy production, manifested in the non-equilibrium thermodynamic equations. The Ornstein-Uhlenbeck process and more specific examples, the spatial stochastic neuronal model, in particular, are studied to test and illustrate the general theory. This theoretical framework is particularly suitable to study the non-equilibrium (thermo)dynamics of spatially inhomogeneous systems abundant in nature. This paper is the second of a series
Entropy production in a fluid-solid system far from thermodynamic equilibrium.
Chung, Bong Jae; Ortega, Blas; Vaidya, Ashwin
2017-11-24
The terminal orientation of a rigid body in a moving fluid is an example of a dissipative system, out of thermodynamic equilibrium and therefore a perfect testing ground for the validity of the maximum entropy production principle (MaxEP). Thus far, dynamical equations alone have been employed in studying the equilibrium states in fluid-solid interactions, but these are far too complex and become analytically intractable when inertial effects come into play. At that stage, our only recourse is to rely on numerical techniques which can be computationally expensive. In our past work, we have shown that the MaxEP is a reliable tool to help predict orientational equilibrium states of highly symmetric bodies such as cylinders, spheroids and toroidal bodies. The MaxEP correctly helps choose the stable equilibrium in these cases when the system is slightly out of thermodynamic equilibrium. In the current paper, we expand our analysis to examine i) bodies with fewer symmetries than previously reported, for instance, a half-ellipse and ii) when the system is far from thermodynamic equilibrium. Using two-dimensional numerical studies at Reynolds numbers ranging between 0 and 14, we examine the validity of the MaxEP. Our analysis of flow past a half-ellipse shows that overall the MaxEP is a good predictor of the equilibrium states but, in the special case of the half-ellipse with aspect ratio much greater than unity, the MaxEP is replaced by the Min-MaxEP, at higher Reynolds numbers when inertial effects come into play. Experiments in sedimentation tanks and with hinged bodies in a flow tank confirm these calculations.
The Donnan equilibrium: I. On the thermodynamic foundation of the Donnan equation of state
International Nuclear Information System (INIS)
Philipse, A; Vrij, A
2011-01-01
The thermodynamic equilibrium between charged colloids and an electrolyte reservoir is named after Frederic Donnan who first published on it one century ago (Donnan 1911 Z. Electrochem. 17 572). One of the intriguing features of the Donnan equilibrium is the ensuing osmotic equation of state which is a nonlinear one, even when both colloids and ions obey Van 't Hoff's ideal osmotic pressure law. The Donnan equation of state, nevertheless, is internally consistent; we demonstrate it to be a rigorous consequence of the phenomenological thermodynamics of a neutral bulk suspension equilibrating with an infinite salt reservoir. Our proof is based on an exact thermodynamic relation between osmotic pressure and salt adsorption which, when applied to ideal ions, does indeed entail the Donnan equation of state. Our derivation also shows that, contrary to what is often assumed, the Donnan equilibrium does not require ideality of the colloids: the Donnan model merely evaluates the osmotic pressure of homogeneously distributed ions, in excess of the pressure exerted by an arbitrary reference fluid of uncharged colloids. We also conclude that results from the phenomenological Donnan model coincide with predictions from statistical thermodynamics in the limit of weakly charged, point-like colloids.
Thermodynamic parameters for adsorption equilibrium of heavy metals and dyes from wastewaters.
Liu, Xiang; Lee, Duu-Jong
2014-05-01
This meta-analysis evaluates adsorption studies that report thermodynamic parameters for heavy metals and dyes from wastewaters. The adsorbents were derived from agricultural waste, industrial wastes, inorganic particulates, or some natural products. The adsorption mechanisms, derivation of thermodynamic relationships, and possible flaws made in such evaluation are discussed. This analysis shows that conclusions from the examined standard enthalpy and entropy changes are highly contestable. The reason for this flaw may be the poor physical structure of adsorbents tested, such that pore transport controlled the solute flux, leaving a surface reaction process near equilibrium. Copyright © 2013 Elsevier Ltd. All rights reserved.
Statistical thermodynamics and energy exchanges
International Nuclear Information System (INIS)
Oudet, X.
1987-01-01
The probability of finding the energy of a particle in the vicinity of a given energy is determined, taking into account of the conservation of energy during the exchanges of energy. As a result the exchanges which determine the different probabilities also introduce a dependence between them, allowing a full calculation. The solution has the main properties of the distribution of Fermi-Dirac, with the mean energy per particle as variable in place of temperature. It allows to propose a localized model for the conduction electrons [fr
Isospin equilibrium and non-equilibrium in heavy-ion collisions at intermediate energies
International Nuclear Information System (INIS)
Chen Liewen; Ge Lingxiao; Zhang Xiaodong; Zhang Fengshou
1997-01-01
The equilibrium and non-equilibrium of the isospin degree of freedom are studied in terms of an isospin-dependent QMD model, which includes isospin-dependent symmetry energy, Coulomb energy, N-N cross sections and Pauli blocking. It is shown that there exists a transition from the isospin equilibrium to non-equilibrium as the incident energy from below to above a threshold energy in central, asymmetric heavy-ion collisions. Meanwhile, it is found that the phenomenon results from the co-existence and competition of different reaction mechanisms, namely, the isospin degree of freedom reaches an equilibrium if the incomplete fusion (ICF) component is dominant and does not reach equilibrium if the fragmentation component is dominant. Moreover, it is also found that the isospin-dependent N-N cross sections and symmetry energy are crucial for the equilibrium of the isospin degree of freedom in heavy-ion collisions around the Fermi energy. (author)
Non-equilibrium thermodynamics theory of econometric source discovery for large data analysis
van Bergem, Rutger; Jenkins, Jeffrey; Benachenhou, Dalila; Szu, Harold
2014-05-01
Almost all consumer and firm transactions are achieved using computers and as a result gives rise to increasingly large amounts of data available for analysts. The gold standard in Economic data manipulation techniques matured during a period of limited data access, and the new Large Data Analysis (LDA) paradigm we all face may quickly obfuscate most tools used by Economists. When coupled with an increased availability of numerous unstructured, multi-modal data sets, the impending 'data tsunami' could have serious detrimental effects for Economic forecasting, analysis, and research in general. Given this reality we propose a decision-aid framework for Augmented-LDA (A-LDA) - a synergistic approach to LDA which combines traditional supervised, rule-based Machine Learning (ML) strategies to iteratively uncover hidden sources in large data, the artificial neural network (ANN) Unsupervised Learning (USL) at the minimum Helmholtz free energy for isothermal dynamic equilibrium strategies, and the Economic intuitions required to handle problems encountered when interpreting large amounts of Financial or Economic data. To make the ANN USL framework applicable to economics we define the temperature, entropy, and energy concepts in Economics from non-equilibrium molecular thermodynamics of Boltzmann viewpoint, as well as defining an information geometry, on which the ANN can operate using USL to reduce information saturation. An exemplar of such a system representation is given for firm industry equilibrium. We demonstrate the traditional ML methodology in the economics context and leverage firm financial data to explore a frontier concept known as behavioral heterogeneity. Behavioral heterogeneity on the firm level can be imagined as a firm's interactions with different types of Economic entities over time. These interactions could impose varying degrees of institutional constraints on a firm's business behavior. We specifically look at behavioral heterogeneity for firms
Non-Equilibrium Thermodynamic Chemistry and the Composition of the Atmosphere of Mars
Levine, J. S.; Summers, M. E.
2003-01-01
A high priority objective of the Mars Exploration Program is to Determine if life exists today (MEPAG Goal I, Objective A). The measurement of gases of biogenic origin may be an approach to detect the presence of microbial life on the surface or subsurface of Mars. Chemical thermodynamic calculations indicate that on both Earth and Mars, certain gases should exist in extremely low concentrations, if at all. Microbial metabolic activity is an important non-equilibrium chemistry process on Earth, and if microbial life exists on Mars, may be an important nonequilibrium chemistry process on Mars. The non-equilibrium chemistry of the atmosphere of Mars is discussed in this paper.
DEFF Research Database (Denmark)
Jahnke, Annika; MacLeod, Matthew; Wickström, Håkan
2014-01-01
Equilibrium partitioning (EqP) theory is currently the most widely used approach for linking sediment pollution by persistent hydrophobic organic chemicals to bioaccumulation. Most applications of the EqP approach assume (I) a generic relationship between organic carbon-normalized chemical...... chemical concentrations in the silicone, and applying lipid/silicone partition ratios to yield concentrations in lipid at thermodynamic equilibrium with the sediment (CLip⇌Sed). Furthermore, we evaluated the validity of assumption II by comparing CLip⇌Sed of selected persistent, bioaccumulative and toxic...... organic chemicals from sediment useful to prioritize management actions to remediate contaminated sites....
Atomistic modeling of thermodynamic equilibrium and polymorphism of iron
International Nuclear Information System (INIS)
Lee, Tongsik; Baskes, Michael I; Valone, Steven M; Doll, J D
2012-01-01
We develop two new modified embedded-atom method (MEAM) potentials for elemental iron, intended to reproduce the experimental phase stability with respect to both temperature and pressure. These simple interatomic potentials are fitted to a wide variety of material properties of bcc iron in close agreement with experiments. Numerous defect properties of bcc iron and bulk properties of the two close-packed structures calculated with these models are in reasonable agreement with the available first-principles calculations and experiments. Performance at finite temperatures of these models has also been examined using Monte Carlo simulations. We attempt to reproduce the experimental iron polymorphism at finite temperature by means of free energy computations, similar to the procedure previously pursued by Müller et al (2007 J. Phys.: Condens. Matter 19 326220), and re-examine the adequacy of the conclusion drawn in the study by addressing two critical aspects missing in their analysis: (i) the stability of the hcp structure relative to the bcc and fcc structures and (ii) the compatibility between the temperature and pressure dependences of the phase stability. Using two MEAM potentials, we are able to represent all of the observed structural phase transitions in iron. We discuss that the correct reproductions of the phase stability among three crystal structures of iron with respect to both temperature and pressure are incompatible with each other due to the lack of magnetic effects in this class of empirical interatomic potential models. The MEAM potentials developed in this study correctly predict, in the bcc structure, the self-interstitial in the 〈110〉 orientation to be the most stable configuration, and the screw dislocation to have a non-degenerate core structure, in contrast to many embedded-atom method potentials for bcc iron in the literature. (paper)
Directory of Open Access Journals (Sweden)
Yu.G.Rudoy
2005-01-01
Full Text Available The concept of effective temperature (ET T*(T0, T is used in order to approximately "quantize" the thermodynamic functions of the dynamical object which is in the thermal equilibrium with thermal bath being at constant temperature T (T0=E0/kB, where E0 is the ground-state energy, kB - Boltzmann constant, is the characteristic ``quantum'' temperature of the system itself. On these grounds the extensive comparative investigation is carried out for the ``standard model'' of statistical mechanics - the one-dimensional harmonic oscillator (HO. Three well-known approaches are considered and their thermodynamic consequences thoroughly studied. These are: the exact quantum, or non-classical Planck-Einstein approach, intermediate, or semiclassical Bloch-Wigner approach and, finally, the pure classical, or Maxwell-Boltzmann approach.
A development of multi-Species mass transport model considering thermodynamic phase equilibrium
DEFF Research Database (Denmark)
Hosokawa, Yoshifumi; Yamada, Kazuo; Johannesson, Björn
2008-01-01
) variation in solid-phase composition when using different types of cement, (ii) physicochemical evaluation of steel corrosion initiation behaviour by calculating the molar ratio of chloride ion to hydroxide ion [Cl]/[OH] in pore solution, (iii) complicated changes of solid-phase composition caused......In this paper, a multi-species mass transport model, which can predict time dependent variation of pore solution and solid-phase composition due to the mass transport into the hardened cement paste, has been developed. Since most of the multi-species models established previously, based...... on the Poisson-Nernst-Planck theory, did not involve the modeling of chemical process, it has been coupled to thermodynamic equilibrium model in this study. By the coupling of thermodynamic equilibrium model, the multi-species model could simulate many different behaviours in hardened cement paste such as: (i...
Disposal of high level nuclear wastes: Thermodynamic equilibrium and environment ethics
Institute of Scientific and Technical Information of China (English)
RANA Mukhtar Ahmed
2009-01-01
Contamination of soil, water or air, due to a failure of containment or disposal of high level nuclear wastes, can potentially cause serious hazards to the environment or human health. Essential elements of the environment and radioactivity dangers to it are illustrated. Issues of high level nuclear waste disposal are discussed with a focus on thermodynamic equilibrium and environment ethics. Major aspects of the issues are analyzed and described briefly to build a perception of risks involved and ethical implications. Nuclear waste containment repository should be as close as possible to thermodynamic equilibrium. A clear demonstration about safety aspects of nuclear waste management is required in gaining public and political confidence in any possible scheme of permanent disposal. Disposal of high level nuclear waste offers a spectrum of environment connected challenges and a long term future of nuclear power depends on the environment friendly solution of the problem of nuclear wastes.
Disposal of high level nuclear wastes: thermodynamic equilibrium and environment ethics
International Nuclear Information System (INIS)
Rana, M.A.
2009-01-01
Contamination of soil, water or air, due to a failure of containment or disposal of high level nuclear wastes, can potentially cause serious hazards to the environment or human health. Essential elements of the environment and radioactivity dangers to it are illustrated. Issues of high level nuclear waste disposal are discussed with a focus on thermodynamic equilibrium and environment ethics. Major aspects of the issues are analyzed and described briefly to build a perception of risks involved and ethical implications. Nuclear waste containment repository should be as close as possible to thermodynamic equilibrium. A clear demonstration about safety aspects of nuclear waste management is required in gaining public and political confidence in any possible scheme of permanent disposal. Disposal of high level nuclear waste offers a spectrum of environment connected challenges and a long term future of nuclear power depends on the environment friendly solution of the problem of nuclear wastes. (authors)
International Nuclear Information System (INIS)
Maevskii, K. K.; Kinelovskii, S. A.
2015-01-01
The numerical results of modeling of shock wave loading of mixtures with the SiO 2 component are presented. The TEC (thermodynamic equilibrium component) model is employed to describe the behavior of solid and porous multicomponent mixtures and alloys under shock wave loading. State equations of a Mie–Grüneisen type are used to describe the behavior of condensed phases, taking into account the temperature dependence of the Grüneisen coefficient, gas in pores is one of the components of the environment. The model is based on the assumption that all components of the mixture under shock-wave loading are in thermodynamic equilibrium. The calculation results are compared with the experimental data derived by various authors. The behavior of the mixture containing components with a phase transition under high dynamic loads is described
A pseudo-equilibrium thermodynamic model of information processing in nonlinear brain dynamics.
Freeman, Walter J
2008-01-01
Computational models of brain dynamics fall short of performance in speed and robustness of pattern recognition in detecting minute but highly significant pattern fragments. A novel model employs the properties of thermodynamic systems operating far from equilibrium, which is analyzed by linearization near adaptive operating points using root locus techniques. Such systems construct order by dissipating energy. Reinforcement learning of conditioned stimuli creates a landscape of attractors and their basins in each sensory cortex by forming nerve cell assemblies in cortical connectivity. Retrieval of a selected category of stored knowledge is by a phase transition that is induced by a conditioned stimulus, and that leads to pattern self-organization. Near self-regulated criticality the cortical background activity displays aperiodic null spikes at which analytic amplitude nears zero, and which constitute a form of Rayleigh noise. Phase transitions in recognition and recall are initiated at null spikes in the presence of an input signal, owing to the high signal-to-noise ratio that facilitates capture of cortex by an attractor, even by very weak activity that is typically evoked by a conditioned stimulus.
Equilibrium Kinetics and Thermodynamic Studies of the Adsorption of Tartrazine and Sunset Yellow
Directory of Open Access Journals (Sweden)
F. O. Okeola
2017-04-01
Full Text Available Batch adsorption experiment was carried out on freema (combination of Tartrazine and Sunset Yellow an adsorbent prepared from moringa pod. The adsorption capacity of the adsorbent was determined. Effect of such factors as initial concentration of the adsorbate solution, contact time with the adsorbent, pH of the dye solution, and temperature of the dye solution on the adsorption capacity of the absorbent was determined. The result showed that the optimum adsorption was attained at pH of 3, adsorption equilibrium was attained within 60 min. The adsorption capacity increases with increase in initial concentration of the dye solution. The result of the kinetics study showed that the adsorption process was better described by the pseudo-second order rate equation. The adsorption process fitted well with both Freundlich (R2 = 0.983 and Langmuir (R2 = 0.933 models. Thermodynamic result showed ΔH and ΔS were all negative. Gibbs free energy change (ΔG increases with increase in temperature of the dye solution.
Model uncertainties of local-thermodynamic-equilibrium K-shell spectroscopy
Nagayama, T.; Bailey, J. E.; Mancini, R. C.; Iglesias, C. A.; Hansen, S. B.; Blancard, C.; Chung, H. K.; Colgan, J.; Cosse, Ph.; Faussurier, G.; Florido, R.; Fontes, C. J.; Gilleron, F.; Golovkin, I. E.; Kilcrease, D. P.; Loisel, G.; MacFarlane, J. J.; Pain, J.-C.; Rochau, G. A.; Sherrill, M. E.; Lee, R. W.
2016-09-01
Local-thermodynamic-equilibrium (LTE) K-shell spectroscopy is a common tool to diagnose electron density, ne, and electron temperature, Te, of high-energy-density (HED) plasmas. Knowing the accuracy of such diagnostics is important to provide quantitative conclusions of many HED-plasma research efforts. For example, Fe opacities were recently measured at multiple conditions at the Sandia National Laboratories Z machine (Bailey et al., 2015), showing significant disagreement with modeled opacities. Since the plasma conditions were measured using K-shell spectroscopy of tracer Mg (Nagayama et al., 2014), one concern is the accuracy of the inferred Fe conditions. In this article, we investigate the K-shell spectroscopy model uncertainties by analyzing the Mg spectra computed with 11 different models at the same conditions. We find that the inferred conditions differ by ±20-30% in ne and ±2-4% in Te depending on the choice of spectral model. Also, we find that half of the Te uncertainty comes from ne uncertainty. To refine the accuracy of the K-shell spectroscopy, it is important to scrutinize and experimentally validate line-shape theory. We investigate the impact of the inferred ne and Te model uncertainty on the Fe opacity measurements. Its impact is small and does not explain the reported discrepancies.
Directory of Open Access Journals (Sweden)
V. Gunasekar
2013-01-01
Full Text Available Carbon synthesized from plant leaf powder was employed for the adsorption of methylene blue from aqueous effluent. Effects of pH (2, 4, 6, 8, and 9, dye concentration (50, 100, 150, and 200 mg/dm3, adsorbent dosage (0.5, 1.0, 1.5, and 2.0 g/dm3, and temperature (303, 313, and 323 K were studied. The process followed pseudo-second-order kinetics. Equilibrium data was examined with Langmuir and Freundlich isotherm models and Langmuir model was found to be the best fitting model with high R2 and low chi2 values. Langmuir monolayer adsorption capacity of the adsorbent was found to be 61.22 mg/g. From the thermodynamic analysis, ΔH, ΔG, and ΔS values for the adsorption of MB onto the plant leaf carbon were found out. From the values of free energy change, the process was found out to be feasible process. From the magnitude of ΔH, the process was found to be endothermic physisorption.
Wellen Rudd, Bethany A; Vidalis, Andrew S; Allen, Heather C
2018-04-16
Of the major cations in seawater (Na+, Mg2+, Ca2+, K+), Ca2+ is found to be the most enriched in fine sea spray aerosols (SSA). In this work, we investigate the binding of Ca2+ to the carboxylic acid headgroup of palmitic acid (PA), a marine-abundant fatty acid, and the impact such binding has on the stability of PA monolayers in both equilibrium and non-equilibrium systems. A range of Ca2+ conditions from 10 μM to 300 mM was utilized to represent the relative concentration of Ca2+ in high and low relative humidity aerosol environments. The CO2- stretching modes of PA detected by surface-sensitive infrared reflection-absorption spectroscopy (IRRAS) reveal ionic binding motifs of the Ca2+ ion to the carboxylate group with varying degrees of hydration. Surface tensiometry was used to determine the thermodynamic equilibrium spreading pressure (ESP) of PA on the various aqueous CaCl2 subphases. Up to concentrations of 1 mM Ca2+, each system reached equilibrium, and Ca2+:PA surface complexation gave rise to a lower energy state revealed by elevated surface pressures relative to water. We show that PA films are not thermodynamically stable at marine aerosol-relevant Ca2+ concentrations ([Ca2+] ≥ 10 mM). IRRAS and vibrational sum frequency generation (VSFG) spectroscopy were used to investigate the surface presence of PA on high concentration Ca2+ aqueous subphases. Non-equilibrium relaxation (NER) experiments were also conducted and monitored by Brewster angle microscopy (BAM) to determine the effect of the Ca2+ ions on PA stability. At high surface pressures, the relaxation mechanisms of PA varied among the systems and were dependent on Ca2+ concentration.
Wills, Peter R; Scott, David J; Winzor, Donald J
2012-03-01
This reexamination of a high-speed sedimentation equilibrium distribution for α-chymotrypsin under slightly acidic conditions (pH 4.1, I(M) 0.05) has provided experimental support for the adequacy of nearest-neighbor considerations in the allowance for effects of thermodynamic nonideality in the characterization of protein self-association over a moderate concentration range (up to 8 mg/mL). A widely held but previously untested notion about allowance for thermodynamic nonideality effects is thereby verified experimentally. However, it has also been shown that a greater obstacle to better characterization of protein self-association is likely to be the lack of a reliable estimate of monomer net charge, a parameter that has a far more profound effect on the magnitude of the measured equilibrium constant than any deficiency in current procedures for incorporating the effects of thermodynamic nonideality into the analysis of sedimentation equilibrium distributions reflecting reversible protein self-association. Copyright Â© 2011 Elsevier Inc. All rights reserved.
Tomba, J. Pablo
2017-01-01
The use of free energy plots to understand the concept of thermodynamic equilibrium has been shown to be of great pedagogical value in materials science. Although chemical equilibrium is also amenable to this kind of analysis, it is not part of the agenda of materials science textbooks. Something similar is found in chemistry branches, where free…
International Nuclear Information System (INIS)
Gilles, D.
2005-01-01
This report is devoted to illustrate the power of a Monte Carlo (MC) simulation code to study the thermodynamical properties of a plasma, composed of classical point particles at thermodynamical equilibrium. Such simulations can help us to manage successfully the challenge of taking into account 'exactly' all classical correlations between particles due to density effects, unlike analytical or semi-analytical approaches, often restricted to low dense plasmas. MC simulations results allow to cover, for laser or astrophysical applications, a wide range of thermodynamical conditions from more dense (and correlated) to less dense ones (where potentials are long ranged type). Therefore Yukawa potentials, with a Thomas-Fermi temperature- and density-dependent screening length, are used to describe the effective ion-ion potentials. In this report we present two MC codes ('PDE' and 'PUCE') and applications performed with these codes in different fields (spectroscopy, opacity, equation of state). Some examples of them are discussed and illustrated at the end of the report. (author)
One-dimensional arrays of oscillators: Energy localization in thermal equilibrium
International Nuclear Information System (INIS)
Reigada, R.; Romero, A.H.; Sarmiento, A.; Lindenberg, K.
1999-01-01
All systems in thermal equilibrium exhibit a spatially variable energy landscape due to thermal fluctuations. Thus at any instant there is naturally a thermodynamically driven localization of energy in parts of the system relative to other parts of the system. The specific characteristics of the spatial landscape such as, for example, the energy variance, depend on the thermodynamic properties of the system and vary from one system to another. The temporal persistence of a given energy landscape, that is, the way in which energy fluctuations (high or low) decay toward the thermal mean, depends on the dynamical features of the system. We discuss the spatial and temporal characteristics of spontaneous energy localization in 1D anharmonic chains in thermal equilibrium. copyright 1999 American Institute of Physics
Thermodynamic calculation of a district energy cycle
International Nuclear Information System (INIS)
Hoehlein, B.; Bauer, A.; Kraut, G.; Scherberich, F.D.
1975-08-01
This paper presents a calculation model for a nuclear district energy circuit. Such a circuit means the combination of a steam reforming plant with heat supply from a high-temperature nuclear reactor and a methanation plant with heat production for district heating or electricity production. The model comprises thermodynamic calculations for the endothermic methane reforming reaction as well as the exothermic CO-hydrogenation in adiabatic reactors and allows the optimization of the district energy circuit under consideration. (orig.) [de
International Nuclear Information System (INIS)
Jenne, E.A.; Cowan, C.E.; Robertson, D.E.
1984-01-01
Calculating trace element speciation with a thermodynamic model is often challenged on the basis that the existing thermodynamic data are not sufficiently reliable. Water quality data and corresponding analytical charge-form speciation analysis were available for radionuclides occurring in a low-level radioactive groundwater. This offered an opportunity for comparing the results of an equilibrium thermodynamic model with the results of analytical charge-form speciation. The charge-form speciation was determined using the Battelle Large Volume Water Sampler, which contains consecutive layers of cation resin, anion resin and activated aluminum oxide for retention of cationic, anionic and non-ionic dissolved chemical species, respectively. The thermodynamic speciation of Cs, Cr, Fe, I, Mn, Mo, Na, and Zn was calculated using the MINTEQ geochemical model. Ce, Co, Tc, Np, Pm, and Sb were speciated by hand calculation. Excellent agreement between the analytically determined charge-form and the thermodynamic speciation was observed for 54 Mn, 144 Ce, 131 I, 24 Na, 137 Cs, 99 Mo, 99 Tc, 151 Pm, 239 Np. Organic complexation by natural and/or synthetic organics in the waters may be important in the speciation of 65 An, 60 Co, 131 I, 59 Fe and possibly 51 Cr. Both 124 Sb and 125 Sb appeared to be in redox disequilibria with the groundwater. 29 references, 2 tables
Thermodynamic basis for effective energy utilization
Energy Technology Data Exchange (ETDEWEB)
Rogers, J. T.
1977-10-15
A major difficulty in a quantitative assessment of effective energy utilization is that energy is always conserved (the First Law of Thermodynamics). However, the Second Law of Thermodynamics shows that, although energy cannot be destroyed, it can be degraded to a state in which it is of no further use for performing tasks. Thus, in considering the present world energy crisis, we are not really concerned with the conservation of energy but with the conservation of its ability to perform useful tasks. A measure of this ability is thermodynamic availability or, a less familiar term, exergy. In a real sense, we are concerned with an entropy-crisis, rather than an energy crisis. Analysis of energy processes on an exergy basis provides significantly different insights into the processes than those obtained from a conventional energy analysis. For example, process steam generation in an industrial boiler may appear quite efficient on the basis of a conventional analysis, but is shown to have very low effective use of energy when analyzed on an exergy basis. Applications of exergy analysis to other systems, such as large fossil and nuclear power stations, are discussed, and the benefits of extraction combined-purpose plants are demonstrated. Other examples of the application of the exergy concept in the industrial and residential energy sectors are also given. The concept is readily adaptable to economic optimization. Examples are given of economic optimization on an availability basis of an industrial heat exchanger and of a combined-purpose nuclear power and heavy-water production plant. Finally, the utility of the concept of exergy in assessing the energy requirements of an industrial society is discussed.
Thermodynamical motivation of the Polish energy policy
Directory of Open Access Journals (Sweden)
Ziębik Andrzej
2013-02-01
Full Text Available Basing on the first and second law of thermodynamics the fundamental trends in the Polish energy policy are analysed, including the aspects of environmental protection. The thermodynamical improvement of real processes (reduction of exergy losses is the main way leading to an improvement of the effectivity of energy consumption. If the exergy loss is economically not justified, we have to do with an error from the viewpoint of the second law analysis. The paper contains a thermodynamical analysis of the ratio of final and primary energy, as well as the analysis of the thermo-ecological cost and index of sustainable development concerning primary energy. Analyses of thermo-ecological costs concerning electricity and centralized heat production have been also carried out. The effect of increasing the share of high-efficiency cogeneration has been analyzed, too. Attention has been paid to an improved efficiency of the transmission and distribution of electricity, which is of special importance from the viewpoint of the second law analysis. The improvement of the energy effectivity in industry was analyzed on the example of physical recuperation, being of special importance from the point of view of exergy analysis.
Louw, Jeanne; Schwarz, Cara E; Burger, Andries J
2016-02-01
H2, CH4, CO and CO2 yields were measured during supercritical water gasification (SCWG) of primary paper waste sludge (PWS) at 450°C. Comparing these yields with calculated thermodynamic equilibrium values offer an improved understanding of conditions required to produce near-equilibrium yields. Experiments were conducted at different catalyst loads (0-1g/gPWS) and different reaction times (15-120min) in a batch reactor, using either K2CO3 or Ni/Al2O3-SiO2 as catalyst. K2CO3 up to 1g/gPWS increased the H2 yield significantly to 7.5mol/kgPWS. However, these yields and composition were far from equilibrium values, with carbon efficiency (CE) and energy recovery (ER) of only 29% and 20%, respectively. Addition of 0.5-1g/gPWS Ni/Al2O3-SiO2 resulted in high H2 and CH4 yields (6.8 and 14.8mol/kgPWS), CE of 84-90%, ER of 83% and a gas composition relatively close to the equilibrium values (at hold times of 60-120min). Copyright © 2015 Elsevier Ltd. All rights reserved.
DEFF Research Database (Denmark)
Pissarra, P.D.; Nielsen, Jens Bredal
1997-01-01
This paper describes the thermodynamic analysis of pathways related to penicillin production in Penicillium chrysogenum. First a thermodynamic feasibility analysis is performed of the L-lysine pathway of which one of the precursors for penicillin biosynthesis (alpha-aminoadipic acid......) is an intermediate. It is found that the L-lysine pathway in P. chrysogenum is thermodynamically feasible and that the calculated standard Gibbs free energy values of the two enzymes controlling the pathway flux indicate that they operate far from equilibrium. It is therefore proposed that the regulation of alpha......-aminoadipate reductase by lysine is important to maintain a high concentration of alpha-aminoadipate in order to direct the carbon flux to penicillin production. Secondly the changes in Gibbs free energy in the penicillin biosynthetic pathway during fed-batch cultivation were studied. The analysis showed that all...
International Nuclear Information System (INIS)
Qian, Hong
2014-01-01
We propose a mathematical formulation of the zeroth law of thermodynamics and develop a stochastic dynamical theory, with a consistent irreversible thermodynamics, for systems possessing sustained conservative stationary current in phase space while in equilibrium with a heat bath. The theory generalizes underdamped mechanical equilibrium: dx=gdt+{−D∇ϕdt+√(2D)dB(t)}, with ∇⋅g=0 and {⋯} respectively representing phase-volume preserving dynamics and stochastic damping. The zeroth law implies stationary distribution u ss (x)=e −ϕ(x) . We find an orthogonality ∇ϕ⋅g=0 as a hallmark of the system. Stochastic thermodynamics based on time reversal (t,ϕ,g)→(−t,ϕ,−g) is formulated: entropy production e p # (t)=−dF(t)/dt; generalized “heat” h d # (t)=−dU(t)/dt, U(t)=∫ R n ϕ(x)u(x,t)dx being “internal energy”, and “free energy” F(t)=U(t)+∫ R n u(x,t)lnu(x,t)dx never increases. Entropy follows (dS)/(dt) =e p # −h d # . Our formulation is shown to be consistent with an earlier theory of P. Ao. Its contradistinctions to other theories, potential-flux decomposition, stochastic Hamiltonian system with even and odd variables, Klein–Kramers equation, Freidlin–Wentzell's theory, and GENERIC, are discussed.
Energy field of thermodynamic syste'ms
International Nuclear Information System (INIS)
Volchenkova, R.A.
1984-01-01
To reveal the qualitative and quantitative rules, regulating the properties of macro- and microsystems consideration is being given to the dependence of system enthalpy on environmental conditions. It was concluded that the dependence of material system enthalpy on temperature represents the energy field, containing the energy boundaries of phase states, described by exponential functions, in which the elements are arranged monotonically in the sequence of change of interatomic bonds, correlated with their physicomechanical properties; energy boundaries of phase states at that emanate from a single point, which is a reference a single point, which a reference one for the whole material system and determining its energy state in initial position. The presented energy field of thermodynamic systems enables to consider the change of their physicomechanical properties and energy state in dynamic process, depending on environmental parameters. Energy characteristics of single-component systems (W, Re, Hf, Nb, Mo etc) are given
Binding Energy and Equilibrium of Compact Objects
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Germano M.
2014-04-01
Full Text Available The theoretical analysis of the existence of a limit mass for compact astronomic ob- jects requires the solution of the Einstein’s equations of g eneral relativity together with an appropriate equation of state. Analytical solutions exi st in some special cases like the spherically symmetric static object without energy sou rces that is here considered. Solutions, i.e. the spacetime metrics, can have a singular m athematical form (the so called Schwarzschild metric due to Hilbert or a nonsingula r form (original work of Schwarzschild. The former predicts a limit mass and, conse quently, the existence of black holes above this limit. Here it is shown that, the origi nal Schwarzschild met- ric permits compact objects, without mass limit, having rea sonable values for central density and pressure. The lack of a limit mass is also demonst rated analytically just imposing reasonable conditions on the energy-matter densi ty, of positivity and decreas- ing with radius. Finally the ratio between proper mass and to tal mass tends to 2 for high values of mass so that the binding energy reaches the lim it m (total mass seen by a distant observer. As it is known the negative binding energ y reduces the gravitational mass of the object; the limit of m for the binding energy provides a mechanism for stable equilibrium of any amount of mass to contrast the gravitatio nal collapse.
Holographic free energy and thermodynamic geometry
Ghorai, Debabrata; Gangopadhyay, Sunandan
2016-12-01
We obtain the free energy and thermodynamic geometry of holographic superconductors in 2+1 dimensions. The gravitational theory in the bulk dual to this 2+1-dimensional strongly coupled theory lives in the 3+1 dimensions and is that of a charged AdS black hole together with a massive charged scalar field. The matching method is applied to obtain the nature of the fields near the horizon using which the holographic free energy is computed through the gauge/gravity duality. The critical temperature is obtained for a set of values of the matching point of the near horizon and the boundary behaviour of the fields in the probe limit approximation which neglects the back reaction of the matter fields on the background spacetime geometry. The thermodynamic geometry is then computed from the free energy of the boundary theory. From the divergence of the thermodynamic scalar curvature, the critical temperature is obtained once again. We then compare this result for the critical temperature with that obtained from the matching method.
Holographic free energy and thermodynamic geometry
International Nuclear Information System (INIS)
Ghorai, Debabrata; Gangopadhyay, Sunandan
2016-01-01
We obtain the free energy and thermodynamic geometry of holographic superconductors in 2 + 1 dimensions. The gravitational theory in the bulk dual to this 2 + 1-dimensional strongly coupled theory lives in the 3 + 1 dimensions and is that of a charged AdS black hole together with a massive charged scalar field. The matching method is applied to obtain the nature of the fields near the horizon using which the holographic free energy is computed through the gauge/gravity duality. The critical temperature is obtained for a set of values of the matching point of the near horizon and the boundary behaviour of the fields in the probe limit approximation which neglects the back reaction of the matter fields on the background spacetime geometry. The thermodynamic geometry is then computed from the free energy of the boundary theory. From the divergence of the thermodynamic scalar curvature, the critical temperature is obtained once again. We then compare this result for the critical temperature with that obtained from the matching method. (orig.)
Holographic free energy and thermodynamic geometry
Energy Technology Data Exchange (ETDEWEB)
Ghorai, Debabrata [S.N. Bose National Centre for Basic Sciences, Kolkata (India); Gangopadhyay, Sunandan [Indian Institute of Science Education and Research, Kolkata, Nadia (India); West Bengal State University, Department of Physics, Barasat (India); Inter University Centre for Astronomy and Astrophysics, Pune (India)
2016-12-15
We obtain the free energy and thermodynamic geometry of holographic superconductors in 2 + 1 dimensions. The gravitational theory in the bulk dual to this 2 + 1-dimensional strongly coupled theory lives in the 3 + 1 dimensions and is that of a charged AdS black hole together with a massive charged scalar field. The matching method is applied to obtain the nature of the fields near the horizon using which the holographic free energy is computed through the gauge/gravity duality. The critical temperature is obtained for a set of values of the matching point of the near horizon and the boundary behaviour of the fields in the probe limit approximation which neglects the back reaction of the matter fields on the background spacetime geometry. The thermodynamic geometry is then computed from the free energy of the boundary theory. From the divergence of the thermodynamic scalar curvature, the critical temperature is obtained once again. We then compare this result for the critical temperature with that obtained from the matching method. (orig.)
Bağda, Esra; Tuzen, Mustafa; Sarı, Ahmet
2017-09-01
Removal of toxic chemicals from environmental samples with low-cost methods and materials are very useful approach for especially large-scale applications. Green algae are highly abundant biomaterials which are employed as useful biosorbents in many studies. In the present study, an interesting type of green algae, Cladophora hutchinsiae (C. hutchinsiae) was used for removal of highly toxic chemical such as uranium. The pH, biosorbent concentration, contact time and temperature were optimized as 5.0, 12 g/L, 60 min and 20 °C, respectively. For the equilibrium calculations, three well known isotherm models (Langmuir, Freundlich and Dubinin-Radushkevich) were employed. The maximum biosorption capacity of the biosorbent was calculated as about 152 mg/g under the optimum batch conditions. The mean energy of biosorption was calculated as 8.39 kJ/mol from the D-R biosorption isotherm. The thermodynamic and kinetic characteristics of biosorption were also investigated to explain the nature of the process. The kinetic data best fits the pseudo-second-order kinetic model with a regression coefficient of >0.99 for all studied temperatures. The calculated ΔH° and ΔG° values showed that the biosorption process is exothermic and spontaneous for temperatures between 293 and 333 K. Furthermore, after seven cycling process, the sorption and desorption efficiencies of the biosorbent were found to be 70, and 58%, respectively meaning that the biosorbent had sufficiently high reusability performance as a clean-up tool. Copyright © 2017 Elsevier Ltd. All rights reserved.
Faghihi, Mustafa; Scheffel, Jan; Spies, Guenther O.
1988-05-01
Stability of the thermodynamic equilibrium is put forward as a simple test of the validity of dynamic equations, and is applied to perpendicular gyroviscous magnetohydrodynamics (i.e., perpendicular magnetohydrodynamics with gyroviscosity added). This model turns out to be invalid because it predicts exponentially growing Alfven waves in a spatially homogeneous static equilibrium with scalar pressure.
International Nuclear Information System (INIS)
Faghihi, M.; Scheffel, J.; Spies, G.O.
1988-01-01
Stability of the thermodynamic equilibrium is put forward as a simple test of the validity of dynamic equations, and is applied to perpendicular gyroviscous magnetohydrodynamics (i.e., perpendicular magnetohydrodynamics with gyroviscosity added). This model turns out to be invalid because it predicts exponentially growing Alfven waves in a spatially homogeneous static equilibrium with scalar pressure
International Nuclear Information System (INIS)
Perez, Brenda; Malpiedi, Luciana Pellegrini; Tubío, Gisela; Nerli, Bibiana; Alcântara Pessôa Filho, Pedro de
2013-01-01
Highlights: ► Binodal data of systems (water + polyethyleneglycol + sodium) succinate are reported. ► Pitzer model describes the phase equilibrium of systems formed by polyethyleneglycol and biodegradable salts satisfactorily. ► This simple thermodynamic framework was able to predict the partitioning behaviour of model proteins acceptably well. - Abstract: Phase diagrams of sustainable aqueous two-phase systems (ATPSs) formed by polyethyleneglycols (PEGs) of different average molar masses (4000, 6000, and 8000) and sodium succinate are reported in this work. Partition coefficients (Kps) of seven model proteins: bovine serum albumin, catalase, beta-lactoglobulin, alpha-amylase, lysozyme, pepsin, urease and trypsin were experimentally determined in these systems and in ATPSs formed by the former PEGs and other biodegradable sodium salts: citrate and tartrate. An extension of Pitzer model comprising long and short-range term contributions to the excess Gibbs free energy was used to describe the (liquid + liquid) equilibrium. Comparison between experimental and calculated tie line data showed mean deviations always lower than 3%, thus indicating a good correlation. The partition coefficients were modeled by using the same thermodynamic approach. Predicted and experimental partition coefficients correlated quite successfully. Mean deviations were found to be lower than the experimental uncertainty for most of the assayed proteins.
Thermodynamics and proton activities of protic ionic liquids with quantum cluster equilibrium theory
Ingenmey, Johannes; von Domaros, Michael; Perlt, Eva; Verevkin, Sergey P.; Kirchner, Barbara
2018-05-01
We applied the binary Quantum Cluster Equilibrium (bQCE) method to a number of alkylammonium-based protic ionic liquids in order to predict boiling points, vaporization enthalpies, and proton activities. The theory combines statistical thermodynamics of van-der-Waals-type clusters with ab initio quantum chemistry and yields the partition functions (and associated thermodynamic potentials) of binary mixtures over a wide range of thermodynamic phase points. Unlike conventional cluster approaches that are limited to the prediction of thermodynamic properties, dissociation reactions can be effortlessly included into the bQCE formalism, giving access to ionicities, as well. The method is open to quantum chemical methods at any level of theory, but combination with low-cost composite density functional theory methods and the proposed systematic approach to generate cluster sets provides a computationally inexpensive and mostly parameter-free way to predict such properties at good-to-excellent accuracy. Boiling points can be predicted within an accuracy of 50 K, reaching excellent accuracy for ethylammonium nitrate. Vaporization enthalpies are predicted within an accuracy of 20 kJ mol-1 and can be systematically interpreted on a molecular level. We present the first theoretical approach to predict proton activities in protic ionic liquids, with results fitting well into the experimentally observed correlation. Furthermore, enthalpies of vaporization were measured experimentally for some alkylammonium nitrates and an excellent linear correlation with vaporization enthalpies of their respective parent amines is observed.
Deviation from local thermodynamic equilibrium in a cesium-seeded argon plasma
International Nuclear Information System (INIS)
Stefanov, B.; Zarkova, L.
1985-11-01
The possibility of deviations from local thermodynamic equilibrium of a cesium seeded argon plasma has been analyzed. A four level model of cesium has been employed. Overpopulations of the ground state and the first excited state as well as the corresponding reduction of the electron density are calculated for cylindrical discharge structures by solving stationary rate equations. Numerical results are presented. These results indicate that in a large regime of plasma conditions the LTE assumption is valid for electron temperatures larger than 3000 K. (orig.)
Directory of Open Access Journals (Sweden)
naghmouchi nahed
2016-04-01
Full Text Available The adsorption capacity of two anionic textile dyes (RR120 and BB150 on DMSO intercalated Tunisian raw clay was investigated with respect to contact time, initial dye concentration, pH and Temperature. The equilibrium data were fitted into Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms. The kinetic parameters were calculated using pseudo-first order, pseudo second-order, intra-particle diffusion and Elovich kinetic models. The thermodynamic parameters (DH°, DS° and DG° of the adsorption process were also evaluated.
International Nuclear Information System (INIS)
Peerenboom, Kim; Van Boxtel, Jochem; Janssen, Jesper; Van Dijk, Jan
2014-01-01
The usage of the local thermodynamic equilibrium (LTE) approximation can be a very powerful assumption for simulations of plasmas in or close to equilibrium. In general, the elemental composition in LTE is not constant in space and effects of mixing and demixing have to be taken into account using the Stefan–Maxwell diffusion description. In this paper, we will introduce a method to discretize the resulting coupled set of elemental continuity equations. The coupling between the equations is taken into account by the introduction of the concept of a Péclet matrix. It will be shown analytically and numerically that the mass and charge conservation constraints can be fulfilled exactly. Furthermore, a case study is presented to demonstrate the applicability of the method to a simulation of a mercury-free metal-halide lamp. The source code for the simulations presented in this paper is provided as supplementary material (stacks.iop.org/JPhysD/47/425202/mmedia). (paper)
Energy Technology Data Exchange (ETDEWEB)
Polyachenok, O.G. [Department of Chemistry, Mogilev State University of Foodstuffs, 212027 (Belarus)], E-mail: polyachenok@mogilev.by; Dudkina, E.N.; Branovitskaya, N.V. [Department of Chemistry, Mogilev State University of Foodstuffs, 212027 (Belarus); Polyachenok, L.D. [Department of Chemistry, Mogilev State University of A.A. Kuleshov, 212022 (Belarus)
2008-01-30
New data on the dehydration and rehydration processes of calcium, manganese and copper dichlorides are presented that reveal surprising, in a certain sense, behaviour difficult to be explained for the last two chlorides in terms of the usual conception of thermodynamic equilibrium. A substantial role of a super disperse phase at studying the equilibrium of the thermal decomposition of a hydrate is postulated to explain the experimental results for manganese and copper dichlorides. It is shown that the formation of such a phase of the hydrate is able to change appreciably the experimental results, causing the increase of water vapour pressure and the decrease of the derived enthalpy of a reaction. The results obtained allow to understand the reasons for considerable differences of some literature data. They enable to receive more precise and reliable data for thermal dehydration and probably for some other decomposition processes.
Elemental transport coefficients in viscous plasma flows near local thermodynamic equilibrium
International Nuclear Information System (INIS)
Orsini, Alessio; Kustova, Elena V.
2009-01-01
We propose a convenient formulation of elemental transport coefficients in chemically reacting and plasma flows locally approaching thermodynamic equilibrium. A set of transport coefficients for elemental diffusion velocities, heat flux, and electric current is introduced. These coefficients relate the transport fluxes with the electric field and with the spatial gradients of elemental fractions, pressure, and temperature. The proposed formalism based on chemical elements and fully symmetric with the classical transport theory based on chemical species, is particularly suitable to model mixing and demixing phenomena due to diffusion of chemical elements. The aim of this work is threefold: to define a simple and rigorous framework suitable for numerical implementation, to allow order of magnitude estimations and qualitative predictions of elemental transport phenomena, and to gain a deeper insight into the physics of chemically reacting flows near local equilibrium.
Local thermodynamic equilibrium in a laser-induced plasma evidenced by blackbody radiation
Hermann, Jörg; Grojo, David; Axente, Emanuel; Craciun, Valentin
2018-06-01
We show that the plasma produced by laser ablation of solid materials in specific conditions has an emission spectrum that is characterized by the saturation of the most intense spectral lines at the blackbody radiance. The blackbody temperature equals the excitation temperature of atoms and ions, proving directly and unambiguously a plasma in local thermodynamic equilibrium. The present investigations take benefit from the very rich and intense emission spectrum generated by ablation of a nickel-chromium-molybdenum alloy. This alternative and direct proof of the plasma equilibrium state re-opens the perspectives of quantitative material analyses via calibration-free laser-induced breakdown spectroscopy. Moreover, the unique properties of this laser-produced plasma promote its use as radiation standard for intensity calibration of spectroscopic instruments.
Irreversible thermodynamics of dark energy on the entropy-corrected apparent horizon
Energy Technology Data Exchange (ETDEWEB)
Karami, K; Sahraei, N [Department of Physics, University of Kurdistan, Pasdaran Street, Sanandaj (Iran, Islamic Republic of); Jamil, M, E-mail: KKarami@uok.ac.i, E-mail: mjamil@camp.nust.edu.p [Center for Advanced Mathematics and Physics (CAMP), National University of Sciences and Technology (NUST), Islamabad (Pakistan)
2010-10-15
We study the irreversible (non-equilibrium) thermodynamics of the Friedmann-Robertson-Walker (FRW) universe containing only dark energy. Using the modified entropy-area relation that is motivated by loop quantum gravity, we calculate the entropy-corrected form of the apparent horizon of the FRW universe.
International Nuclear Information System (INIS)
Gao Zhi-Yuan; Xue Xiao-Wei; Li Jiang-Jiang; Wang Xun; Xing Yan-Hui; Cui Bi-Feng; Zou De-Shu
2016-01-01
Frank’s theory describes that a screw dislocation will produce a pit on the surface, and has been evidenced in many material systems including GaN. However, the size of the pit calculated from the theory deviates significantly from experimental result. Through a careful observation of the variations of surface pits and local surface morphology with growing temperature and V/III ratio for c -plane GaN, we believe that Frank’s model is valid only in a small local surface area where thermodynamic equilibrium state can be assumed to stay the same. If the kinetic process is too vigorous or too slow to reach a balance, the local equilibrium range will be too small for the center and edge of the screw dislocation spiral to be kept in the same equilibrium state. When the curvature at the center of the dislocation core reaches the critical value 1/ r 0 , at the edge of the spiral, the accelerating rate of the curvature may not fall to zero, so the pit cannot reach a stationary shape and will keep enlarging under the control of minimization of surface energy to result in a large-sized surface pit. (paper)
Zhi-Yuan, Gao; Xiao-Wei, Xue; Jiang-Jiang, Li; Xun, Wang; Yan-Hui, Xing; Bi-Feng, Cui; De-Shu, Zou
2016-06-01
Frank’s theory describes that a screw dislocation will produce a pit on the surface, and has been evidenced in many material systems including GaN. However, the size of the pit calculated from the theory deviates significantly from experimental result. Through a careful observation of the variations of surface pits and local surface morphology with growing temperature and V/III ratio for c-plane GaN, we believe that Frank’s model is valid only in a small local surface area where thermodynamic equilibrium state can be assumed to stay the same. If the kinetic process is too vigorous or too slow to reach a balance, the local equilibrium range will be too small for the center and edge of the screw dislocation spiral to be kept in the same equilibrium state. When the curvature at the center of the dislocation core reaches the critical value 1/r 0, at the edge of the spiral, the accelerating rate of the curvature may not fall to zero, so the pit cannot reach a stationary shape and will keep enlarging under the control of minimization of surface energy to result in a large-sized surface pit. Project supported by the National Natural Science Foundation of China (Grant Nos. 11204009 and 61204011) and the Beijing Municipal Natural Science Foundation, China (Grant No. 4142005).
Directory of Open Access Journals (Sweden)
K. S. Kalogerakis
2018-01-01
Full Text Available The question of whether mesospheric OH(v rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(v rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-v vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(v rotational population distributions. Rapid OH(high-v + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-v rotational distributions. The effective rotational temperatures of mesospheric OH(v are found to deviate from local thermodynamic equilibrium for all observed vibrational levels. Dedicated to Tom G. Slanger in celebration of his 5 decades of research in aeronomy.
Oyelude, Emmanuel O; Awudza, Johannes A M; Twumasi, Sylvester K
2017-09-22
Low-cost teak leaf litter powder (TLLP) was prepared as possible substitute for activated carbon. The feasibility of using the adsorbent to remove eosin yellow (EY) dye from aqueous solution was investigated through equilibrium adsorption, kinetic and thermodynamic studies. The removal of dye from aqueous solution was feasible but influenced by temperature, pH, adsorbent dosage and contact time. Variation in the initial concentration of dye did not influence the equilibrium contact time. Optimum adsorption of dye occurred at low adsorbent dosages, alkaline pH and high temperatures. Langmuir isotherm model best fit the equilibrium adsorption data and the maximum monolayer capacity of the adsorbent was 31.64 mg g -1 at 303 K. The adsorption process was best described by pseudo-second order kinetic model at 303 K. Boundary layer diffusion played a key role in the adsorption process. The mechanism of uptake of EY by TLLP was controlled by both liquid film diffusion and intraparticle diffusion. The values of mean adsorption free energy, E (7.91 kJ mol -1 ), and standard enthalpy, ΔH° (+13.34 kJ mol -1 ), suggest physical adsorption. The adsorption process was endothermic and spontaneous. Teak leaf litter powder is a promising low-cost adsorbent for treating wastewaters containing eosin yellow.
Teaching elementary thermodynamics and energy conversion: Opinions
International Nuclear Information System (INIS)
Gaggioli, Richard A.
2010-01-01
This presentation deals with innovation in teaching and understanding of thermodynamic principles. Key features of the approach being advocated are: (a) postulation of the existence of entropy, (b) explicitly associating energy transfers with other transports, (c) stating the 2nd Law in terms of Gibbs' available-energy, (d) systematic use of software such as EES. The paper outlines and elaborates upon an introductory course. Major headings in the course are: basic concepts: properties, additive properties and balances, primitive properties, energy, 1st Law. entropy, elementary academic applications of balances, available-energy, second law, exergy, thermostatic property relations, EES. Applications to processes, fluid flow, Heat transfer, thermochemical. Applications to devices, single-process, compound-process, systems (consisting of devices and processes functioning together).
Popovas, A.; Jørgensen, U. G.
2016-11-01
Context. Hydrogen is the most abundant molecule in the Universe. Its thermodynamic quantities dominate the physical conditions in molecular clouds, protoplanetary disks, etc. It is also of high interest in plasma physics. Therefore thermodynamic data for molecular hydrogen have to be as accurate as possible in a wide temperature range. Aims: We here rigorously show the shortcomings of various simplifications that are used to calculate the total internal partition function. These shortcomings can lead to errors of up to 40 percent or more in the estimated partition function. These errors carry on to calculations of thermodynamic quantities. Therefore a more complicated approach has to be taken. Methods: Seven possible simplifications of various complexity are described, together with advantages and disadvantages of direct summation of experimental values. These were compared to what we consider the most accurate and most complete treatment (case 8). Dunham coefficients were determined from experimental and theoretical energy levels of a number of electronically excited states of H2. Both equilibrium and normal hydrogen was taken into consideration. Results: Various shortcomings in existing calculations are demonstrated, and the reasons for them are explained. New partition functions for equilibrium, normal, and ortho and para hydrogen are calculated and thermodynamic quantities are reported for the temperature range 1-20 000 K. Our results are compared to previous estimates in the literature. The calculations are not limited to the ground electronic state, but include all bound and quasi-bound levels of excited electronic states. Dunham coefficients of these states of H2 are also reported. Conclusions: For most of the relevant astrophysical cases it is strongly advised to avoid using simplifications, such as a harmonic oscillator and rigid rotor or ad hoc summation limits of the eigenstates to estimate accurate partition functions and to be particularly careful when
Bharate, Sonali S; Vishwakarma, Ram A
2015-04-01
An early prediction of solubility in physiological media (PBS, SGF and SIF) is useful to predict qualitatively bioavailability and absorption of lead candidates. Despite of the availability of multiple solubility estimation methods, none of the reported method involves simplified fixed protocol for diverse set of compounds. Therefore, a simple and medium-throughput solubility estimation protocol is highly desirable during lead optimization stage. The present work introduces a rapid method for assessment of thermodynamic equilibrium solubility of compounds in aqueous media using 96-well microplate. The developed protocol is straightforward to set up and takes advantage of the sensitivity of UV spectroscopy. The compound, in stock solution in methanol, is introduced in microgram quantities into microplate wells followed by drying at an ambient temperature. Microplates were shaken upon addition of test media and the supernatant was analyzed by UV method. A plot of absorbance versus concentration of a sample provides saturation point, which is thermodynamic equilibrium solubility of a sample. The established protocol was validated using a large panel of commercially available drugs and with conventional miniaturized shake flask method (r(2)>0.84). Additionally, the statistically significant QSPR models were established using experimental solubility values of 52 compounds. Copyright © 2015 Elsevier Ltd. All rights reserved.
Absolute determination of the gelling point of gelatin under quasi-thermodynamic equilibrium.
Bellini, Franco; Alberini, Ivana; Ferreyra, María G; Rintoul, Ignacio
2015-05-01
Thermodynamic studies on phase transformation of biopolymers in solution are useful to understand their nature and to evaluate their technological potentials. Thermodynamic studies should be conducted avoiding time-related phenomena. This condition is not easily achieved in hydrophilic biopolymers. In this contribution, the simultaneous effects of pH, salt concentration, and cooling rate (Cr) on the folding from random coil to triple helical collagen-like structures of gelatin were systematically studied. The phase transformation temperature at the absolute invariant condition of Cr = 0 °C/min (T(T)Cr=0) ) is introduced as a conceptual parameter to study phase transformations in biopolymers under quasi-thermodynamic equilibrium and avoiding interferences coming from time-related phenomena. Experimental phase diagrams obtained at different Cr are presented. The T(T)(Cr=0) compared with pH and TT(Cr=0) compared with [NaCl] diagram allowed to explore the transformation process at Cr = 0 °C/min. The results were explained by electrostatic interactions between the biopolymers and its solvation milieu. © 2015 Institute of Food Technologists®
Pyroelectric Energy Harvesting: With Thermodynamic-Based Cycles
Saber Mohammadi; Akram Khodayari
2012-01-01
This work deals with energy harvesting from temperature variations using ferroelectric materials as a microgenerator. The previous researches show that direct pyroelectric energy harvesting is not effective, whereas thermodynamic-based cycles give higher energy. Also, at different temperatures some thermodynamic cycles exhibit different behaviours. In this paper pyroelectric energy harvesting using Lenoir and Ericsson thermodynamic cycles has been studied numerically and the two cycles were c...
Pump, Eva
2015-02-24
Abstract: This work was conducted to provide an overview on the position of the thermodynamic cis–trans equilibrium of 85 conventional and X-chelated alkylidene-ruthenium complexes (X=O, S, Se, N, P, Cl, I, Br). The reported energies (ΔE) were obtained through single-point calculations with M06 functional and TZVP basis set from BP86/SVP-optimized cis- and trans-dichloro geometries and using the polarizable continuum model to simulate the influence of the solvent. Dichloromethane and toluene were selected as examples for solvents with high and low dielectric constants. The obtained relative stabilities of the cis- and trans-dihalo derivatives of the respective alkylidene complexes will serve for a better explanation of their catalytic activity as has been disclosed herein with selected examples.Graphical abstract: [Figure not available: see fulltext.
Energy Technology Data Exchange (ETDEWEB)
Rathinam, Aravindhan [Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600020 (India); Zou, Linda, E-mail: linda.zou@unisa.edu.au [SA Water Centre for Water Management and Reuse, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095 (Australia)
2010-12-15
Batch biosorption experiments have been carried out for the removal of bovine serum albumin (BSA) from simulated industrial wastewater onto Ulva lactuca seaweed. Various vital parameters influencing the biosorption process such as initial concentration of BSA, pH of the solution, adsorbent dosage and temperature have been determined. The biosorption kinetics follows a pseudo-second order kinetic model. Equilibrium isotherm studies demonstrate that the biosorption followed the Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Various thermodynamic parameters such as changes in enthalpy, free energy and entropy have been calculated. The positive value of {Delta}H{sup o} and the negative value of {Delta}G{sup o} show that the sorption process is endothermic and spontaneous. The positive value of change in entropy {Delta}S{sup o} shows increased randomness at the solid-liquid interface during the biosorption of BSA onto U. lactuca seaweed.
Rathinam, Aravindhan; Zou, Linda
2010-12-15
Batch biosorption experiments have been carried out for the removal of bovine serum albumin (BSA) from simulated industrial wastewater onto Ulva lactuca seaweed. Various vital parameters influencing the biosorption process such as initial concentration of BSA, pH of the solution, adsorbent dosage and temperature have been determined. The biosorption kinetics follows a pseudo-second order kinetic model. Equilibrium isotherm studies demonstrate that the biosorption followed the Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Various thermodynamic parameters such as changes in enthalpy, free energy and entropy have been calculated. The positive value of ΔH° and the negative value of ΔG° show that the sorption process is endothermic and spontaneous. The positive value of change in entropy ΔS° shows increased randomness at the solid-liquid interface during the biosorption of BSA onto U. lactuca seaweed. Copyright © 2010 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Rathinam, Aravindhan; Zou, Linda
2010-01-01
Batch biosorption experiments have been carried out for the removal of bovine serum albumin (BSA) from simulated industrial wastewater onto Ulva lactuca seaweed. Various vital parameters influencing the biosorption process such as initial concentration of BSA, pH of the solution, adsorbent dosage and temperature have been determined. The biosorption kinetics follows a pseudo-second order kinetic model. Equilibrium isotherm studies demonstrate that the biosorption followed the Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Various thermodynamic parameters such as changes in enthalpy, free energy and entropy have been calculated. The positive value of ΔH o and the negative value of ΔG o show that the sorption process is endothermic and spontaneous. The positive value of change in entropy ΔS o shows increased randomness at the solid-liquid interface during the biosorption of BSA onto U. lactuca seaweed.
Directory of Open Access Journals (Sweden)
Rutger de Wit
2005-09-01
Full Text Available Sven Erik Jørgensen has boldly proposed a “Fourth Law of Thermodynamics” which he also advocates as the “Ecological Law of Thermodynamics” or ELT (Integration of Ecosystem Theories: A Pattern, Kluwer Academic Publisher. This Law is still a hypothesis and can be tested. I disagree with the generalised way he uses the term “exergy” in his approach. Exergy is commonly defined as a measure of the work capacity of a system. According to the physicists Boltzmann information embodies energy. Jørgensen takes this into account when considering the “exergy” stored in ecosystems; hence, according to his way of calculating the genetic information of the organisms is the mayor contribution to “exergy”. I argue that energy has been embodied in the information during a historical process and that because of fundamental irreversibility this energy cannot be extracted again for work capacity. Moreover, other phenomena mentioned earlier by Ramon Margalef, demonstrate that proliferating information in biota shows uncoupling with respect to its embodied energy content according to the Boltzmann formula. In spite of these objections, some of Sven Erik Jørgensen’s core ideas are exiting and worthwhile testing. I place these within the context of the non-equilibrium thermodynamic theories on “dissipative systems” developed by the physicist Ilya Prigogine.
Energy Technology Data Exchange (ETDEWEB)
Azouaou, N., E-mail: azouaou20@yahoo.fr [Laboratory of Reaction Genius, Faculty of Mechanical and Processes Genius, University of Sciences and Technology Houari - Boumediene, USTHB, BP no 32 El Alia bab ezzouar, 16111 Algiers (Algeria); Sadaoui, Z. [Laboratory of Reaction Genius, Faculty of Mechanical and Processes Genius, University of Sciences and Technology Houari - Boumediene, USTHB, BP no 32 El Alia bab ezzouar, 16111 Algiers (Algeria); Djaafri, A. [Central laboratory, SEAAL, 97 Parc ben omar, Kouba, Algiers (Algeria); Mokaddem, H. [Laboratory of Reaction Genius, Faculty of Mechanical and Processes Genius, University of Sciences and Technology Houari - Boumediene, USTHB, BP no 32 El Alia bab ezzouar, 16111 Algiers (Algeria)
2010-12-15
Adsorption can be used as a cost effective and efficient technique for the removal of toxic heavy metals from wastewater. Waste materials with no further treatment such as coffee grounds from cafeterias may act as adsorbents for the removal of cadmium. Batch kinetic and equilibrium experiments were conducted to study the effects of contact time, adsorbent dose, initial pH, particle size, initial concentration of cadmium and temperature. Three adsorption isotherm models namely, Langmuir, Freundlich and Dubinin-Radushkevich were used to analyse the equilibrium data. The Langmuir isotherm which provided the best correlation for Cd{sup 2+} adsorption onto coffee grounds, shows that the adsorption was favourable and the adsorption capacity found was equal to 15.65 mg g{sup -1}. Thermodynamic parameters were evaluated and the adsorption was exothermic. The equilibrium was achieved less than 120 min. The adsorption kinetic data was fitted with first and second order kinetic models. Finally it was concluded that the cadmium adsorption kinetic onto coffee grounds was well fitted by second order kinetic model rather than first order model. The results suggest that coffee grounds have high possibility to be used as effective and economical adsorbent for Cd{sup 2+} removal.
International Nuclear Information System (INIS)
Azouaou, N.; Sadaoui, Z.; Djaafri, A.; Mokaddem, H.
2010-01-01
Adsorption can be used as a cost effective and efficient technique for the removal of toxic heavy metals from wastewater. Waste materials with no further treatment such as coffee grounds from cafeterias may act as adsorbents for the removal of cadmium. Batch kinetic and equilibrium experiments were conducted to study the effects of contact time, adsorbent dose, initial pH, particle size, initial concentration of cadmium and temperature. Three adsorption isotherm models namely, Langmuir, Freundlich and Dubinin-Radushkevich were used to analyse the equilibrium data. The Langmuir isotherm which provided the best correlation for Cd 2+ adsorption onto coffee grounds, shows that the adsorption was favourable and the adsorption capacity found was equal to 15.65 mg g -1 . Thermodynamic parameters were evaluated and the adsorption was exothermic. The equilibrium was achieved less than 120 min. The adsorption kinetic data was fitted with first and second order kinetic models. Finally it was concluded that the cadmium adsorption kinetic onto coffee grounds was well fitted by second order kinetic model rather than first order model. The results suggest that coffee grounds have high possibility to be used as effective and economical adsorbent for Cd 2+ removal.
Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission
International Nuclear Information System (INIS)
Jacquet, L.; Primout, M.; Kaiser, P.; Clouët, J. F.; Girard, F.; Villette, B.; Reverdin, C.; Oudot, G.
2015-01-01
The x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV x-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics. The incident laser power had a pre-pulse to enhance the x-ray emission of a 1 ns flat-top main pulse. The experimental results have been compared with post-shot simulations performed with the two-dimensional radiation-hydrodynamics code FCI2. A new non-local thermodynamic equilibrium model, NOO-RAD, have been incorporated into FCI2. In this approach, the plasma ionization state is in-line calculated by the atomic physics NOHEL package. In the soft x-ray bands, both simulations using RADIOM [M. Busquet, Phys. Fluids B 5, 4191 (1993)] and NOO-RAD clearly over-predict the powers and energies measured by a broad-band spectrometer. In one case (the iron foil), the discrepancy between the measured and simulated x-ray output is nevertheless significantly reduced when NOO-RAD is used in the simulations. In the multi-keV x-ray bands, the simulations display a strong sensitivity to the coupling between the electron thermal conductivity and the NLTE models, and for some particular combinations of these, provide a close match to the measured emission. The comparison between the measured and simulated H-like to He-like line-intensity ratios deduced from high-resolution spectra indicates higher experimental electron temperatures were achieved, compared to the simulated ones. Measurements of the plasma conditions have been achieved using the Thomson-scattering diagnostic. The electron temperatures are found to range from 3 to 5 keV at the end of the laser pulse and are greater than predicted by the simulations. The measured flow velocities are in reasonable agreement with the calculated ones. This last finding gives us confidence in our numerical predictions for the plasma parameters, which are over that time mainly determined by hydrodynamics, such as the mass densities and
Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission
Jacquet, L.; Primout, M.; Kaiser, P.; Clouët, J. F.; Girard, F.; Villette, B.; Reverdin, C.; Oudot, G.
2015-12-01
The x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV x-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics. The incident laser power had a pre-pulse to enhance the x-ray emission of a 1 ns flat-top main pulse. The experimental results have been compared with post-shot simulations performed with the two-dimensional radiation-hydrodynamics code FCI2. A new non-local thermodynamic equilibrium model, NOO-RAD, have been incorporated into FCI2. In this approach, the plasma ionization state is in-line calculated by the atomic physics NOHEL package. In the soft x-ray bands, both simulations using RADIOM [M. Busquet, Phys. Fluids B 5, 4191 (1993)] and NOO-RAD clearly over-predict the powers and energies measured by a broad-band spectrometer. In one case (the iron foil), the discrepancy between the measured and simulated x-ray output is nevertheless significantly reduced when NOO-RAD is used in the simulations. In the multi-keV x-ray bands, the simulations display a strong sensitivity to the coupling between the electron thermal conductivity and the NLTE models, and for some particular combinations of these, provide a close match to the measured emission. The comparison between the measured and simulated H-like to He-like line-intensity ratios deduced from high-resolution spectra indicates higher experimental electron temperatures were achieved, compared to the simulated ones. Measurements of the plasma conditions have been achieved using the Thomson-scattering diagnostic. The electron temperatures are found to range from 3 to 5 keV at the end of the laser pulse and are greater than predicted by the simulations. The measured flow velocities are in reasonable agreement with the calculated ones. This last finding gives us confidence in our numerical predictions for the plasma parameters, which are over that time mainly determined by hydrodynamics, such as the mass densities and the
Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission
Energy Technology Data Exchange (ETDEWEB)
Jacquet, L., E-mail: laurent.jacquet@cea.fr; Primout, M.; Kaiser, P.; Clouët, J. F.; Girard, F.; Villette, B.; Reverdin, C.; Oudot, G. [CEA, DAM, DIF, F-91297 Arpajon (France)
2015-12-15
The x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV x-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics. The incident laser power had a pre-pulse to enhance the x-ray emission of a 1 ns flat-top main pulse. The experimental results have been compared with post-shot simulations performed with the two-dimensional radiation-hydrodynamics code FCI2. A new non-local thermodynamic equilibrium model, NOO-RAD, have been incorporated into FCI2. In this approach, the plasma ionization state is in-line calculated by the atomic physics NOHEL package. In the soft x-ray bands, both simulations using RADIOM [M. Busquet, Phys. Fluids B 5, 4191 (1993)] and NOO-RAD clearly over-predict the powers and energies measured by a broad-band spectrometer. In one case (the iron foil), the discrepancy between the measured and simulated x-ray output is nevertheless significantly reduced when NOO-RAD is used in the simulations. In the multi-keV x-ray bands, the simulations display a strong sensitivity to the coupling between the electron thermal conductivity and the NLTE models, and for some particular combinations of these, provide a close match to the measured emission. The comparison between the measured and simulated H-like to He-like line-intensity ratios deduced from high-resolution spectra indicates higher experimental electron temperatures were achieved, compared to the simulated ones. Measurements of the plasma conditions have been achieved using the Thomson-scattering diagnostic. The electron temperatures are found to range from 3 to 5 keV at the end of the laser pulse and are greater than predicted by the simulations. The measured flow velocities are in reasonable agreement with the calculated ones. This last finding gives us confidence in our numerical predictions for the plasma parameters, which are over that time mainly determined by hydrodynamics, such as the mass densities and
International Nuclear Information System (INIS)
Sari, Ahmet; Tuzen, Mustafa; Citak, Demirhan; Soylak, Mustafa
2007-01-01
The adsorption of Pb(II) onto Turkish (Bandirma region) kaolinite clay was examined in aqueous solution with respect to the pH, adsorbent dosage, contact time, and temperature. The linear Langmuir and Freundlich models were applied to describe equilibrium isotherms and both models fitted well. The monolayer adsorption capacity was found as 31.75 mg/g at pH 5 and 20 deg. C. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data. The mean free energy of adsorption (13.78 kJ/mol) indicated that the adsorption of Pb(II) onto kaolinite clay may be carried out via chemical ion-exchange mechanism. Thermodynamic parameters, free energy (ΔG o ), enthalpy (ΔH o ) and entropy (ΔS o ) of adsorption were also calculated. These parameters showed that the adsorption of Pb(II) onto kaolinite clay was feasible, spontaneous and exothermic process in nature. Furthermore, the Lagergren-first-order, pseudo-second-order and the intraparticle diffusion models were used to describe the kinetic data. The experimental data fitted well the pseudo-second-order kinetics
Kleidon, A.
2010-01-01
The Earth system is remarkably different from its planetary neighbours in that it shows pronounced, strong global cycling of matter. These global cycles result in the maintenance of a unique thermodynamic state of the Earth's atmosphere which is far from thermodynamic equilibrium (TE). Here, I provide a simple introduction of the thermodynamic basis to understand why Earth system processes operate so far away from TE. I use a simple toy model to illustrate the application of non-equilibrium thermodynamics and to classify applications of the proposed principle of maximum entropy production (MEP) to such processes into three different cases of contrasting flexibility in the boundary conditions. I then provide a brief overview of the different processes within the Earth system that produce entropy, review actual examples of MEP in environmental and ecological systems, and discuss the role of interactions among dissipative processes in making boundary conditions more flexible. I close with a brief summary and conclusion. PMID:20368248
Kleidon, A
2010-05-12
The Earth system is remarkably different from its planetary neighbours in that it shows pronounced, strong global cycling of matter. These global cycles result in the maintenance of a unique thermodynamic state of the Earth's atmosphere which is far from thermodynamic equilibrium (TE). Here, I provide a simple introduction of the thermodynamic basis to understand why Earth system processes operate so far away from TE. I use a simple toy model to illustrate the application of non-equilibrium thermodynamics and to classify applications of the proposed principle of maximum entropy production (MEP) to such processes into three different cases of contrasting flexibility in the boundary conditions. I then provide a brief overview of the different processes within the Earth system that produce entropy, review actual examples of MEP in environmental and ecological systems, and discuss the role of interactions among dissipative processes in making boundary conditions more flexible. I close with a brief summary and conclusion.
Thermodynamic Aspects and Reprogramming Cellular Energy Metabolism during the Fibrosis Process
Directory of Open Access Journals (Sweden)
Alexandre Vallée
2017-11-01
Full Text Available Fibrosis is characterized by fibroblast proliferation and fibroblast differentiation into myofibroblasts, which generate a relaxation-free contraction mechanism associated with excessive collagen synthesis in the extracellular matrix, which promotes irreversible tissue retraction evolving towards fibrosis. From a thermodynamic point of view, the mechanisms leading to fibrosis are irreversible processes that can occur through changing the entropy production rate. The thermodynamic behaviors of metabolic enzymes involved in fibrosis are modified by the dysregulation of both transforming growth factor β (TGF-β signaling and the canonical WNT/β-catenin pathway, leading to aerobic glycolysis, called the Warburg effect. Molecular signaling pathways leading to fibrosis are considered dissipative structures that exchange energy or matter with their environment far from the thermodynamic equilibrium. The myofibroblastic cells arise from exergonic processes by switching the core metabolism from oxidative phosphorylation to glycolysis, which generates energy and reprograms cellular energy metabolism to induce the process of myofibroblast differentiation. Circadian rhythms are far-from-equilibrium thermodynamic processes. They directly participate in regulating the TGF-β and WNT/β-catenin pathways involved in energetic dysregulation and enabling fibrosis. The present review focusses on the thermodynamic implications of the reprogramming of cellular energy metabolism, leading to fibroblast differentiation into myofibroblasts through the positive interplay between TGF-β and WNT/β-catenin pathways underlying in fibrosis.
Correlations in plasma in thermodynamic equilibrium; Les correlations dans un plasma en equilibre
Energy Technology Data Exchange (ETDEWEB)
Yvon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1958-07-01
This paper treats of a fully, ionized plasma in thermodynamic equilibrium. An attempt is made at reviewing the calculation of spatial correlations in such a plasma. The equation of recurrence and the principle of superposition are used. The linear approximation is first treated. The next higher approximation is studied in the case of a neutral homogeneous and isotropic plasma. (author) [French] Un plasma completement ionise est en equilibre thermodynamique. On tente une mise au point du calcul des correlations de position dans ce plasma. On utilise les equations de recurrence et le principe de superposition. On expose d'abord l'approximation lineaire. Dans le cas d'un plasma neutre homogene et isotrope l'etude est poursuivie a l'approximation suivante. (auteur)
Directory of Open Access Journals (Sweden)
Gizem Biçer
2017-06-01
Full Text Available In this study, the effects of adsorption parameters such as initial pH, initial dye concentration, temperature and adsorbent dosage on the colour removal from aqueous solution containing Telon Blue AGLF(TB AGLF textile dye were investigated by NiO based nanomaterials and then the compliance of the equilibrium data with the different isotherm models in the literature was evaluated. In the next step, the adsorption sytem was analyzed in terms of kinetics and thermodynamics. At the end of the study, XRD, SEM and FTIR analysis methods were used for the particle characterization. As a result of the experimental studies, it was detected the successful use of NiO based nanomaterials synthesized by aqueous solution method rarely seen in literature for colour removal. Through this study, it is believed that the additional contributions are provided to the scientific investigations about the recovery of the water resources.
Thompson, Richard A.; Lee, Kam-Pui; Gupta, Roop N.
1991-01-01
The computer codes developed here provide self-consistent thermodynamic and transport properties for equilibrium air for temperatures from 500 to 30000 K over a temperature range of 10 (exp -4) to 10 (exp -2) atm. These properties are computed through the use of temperature dependent curve fits for discrete values of pressure. Interpolation is employed for intermediate values of pressure. The curve fits are based on mixture values calculated from an 11-species air model. Individual species properties used in the mixture relations are obtained from a recent study by the present authors. A review and discussion of the sources and accuracy of the curve fitted data used herein are given in NASA RP 1260.
International Nuclear Information System (INIS)
Aksakal, Ozkan; Ucun, Handan
2010-01-01
This study investigated the biosorption of Reactive Red 195 (RR 195), an azo dye, from aqueous solution by using cone biomass of Pinus sylvestris Linneo. To this end, pH, initial dye concentration, biomass dosage and contact time were studied in a batch biosorption system. Maximum pH for efficient RR 195 biosorption was found to be 1.0 and the initial RR 195 concentration increased with decreasing percentage removal. Biosorption capacity increased from 6.69 mg/g at 20 deg. C to 7.38 mg/g at 50 deg. C for 200 mg/L dye concentration. Kinetics of the interactions was tested by pseudo-first-order and pseudo-second-order kinetics, the Elovich equation and intraparticle diffusion mechanism. Pseudo-second-order kinetic model provided a better correlation for the experimental data studied in comparison to the pseudo-first-order kinetic model and intraparticle diffusion mechanism. Moreover, the Elovich equation also showed a good fit to the experimental data. Freundlich and Langmuir adsorption isotherms were used for the mathematical description of the biosorption equilibrium data. The activation energy of biosorption (Ea) was found to be 8.904 kJ/mol by using the Arrhenius equation. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the study also evaluated the thermodynamic constants of biosorption (ΔG o , ΔH o and ΔS). The results indicate that cone biomass can be used as an effective and low-cost biosorbent to remove reactive dyes from aqueous solution.
International Nuclear Information System (INIS)
Cristoforetti, G.; De Giacomo, A.; Dell'Aglio, M.; Legnaioli, S.; Tognoni, E.; Palleschi, V.; Omenetto, N.
2010-01-01
In the Laser-Induced Breakdown Spectroscopy (LIBS) technique, the existence of Local Thermodynamic Equilibrium (LTE) is the essential requisite for meaningful application of theoretical Boltzmann-Maxwell and Saha-Eggert expressions that relate fundamental plasma parameters and concentration of analyte species. The most popular criterion reported in the literature dealing with plasma diagnostics, and usually invoked as a proof of the existence of LTE in the plasma, is the McWhirter criterion [R.W.P. McWhirter, in: Eds. R.H. Huddlestone, S.L. Leonard, Plasma Diagnostic Techniques, Academic Press, New York, 1965, pp. 201-264]. However, as pointed out in several papers, this criterion is known to be a necessary but not a sufficient condition to insure LTE. The considerations reported here are meant to briefly review the theoretical analysis underlying the concept of thermodynamic equilibrium and the derivation of the McWhirter criterion, and to critically discuss its application to a transient and non-homogeneous plasma, like that created by a laser pulse on solid targets. Specific examples are given of theoretical expressions involving relaxation times and diffusion coefficients, as well as a discussion of different experimental approaches involving space and time-resolved measurements that could be used to complement a positive result of the calculation of the minimum electron number density required for LTE using the McWhirter formula. It is argued that these approaches will allow a more complete assessment of the existence of LTE and therefore permit a better quantitative result. It is suggested that the mere use of the McWhirter criterion to assess the existence of LTE in laser-induced plasmas should be discontinued.
A spreadsheet-coupled SOLGAS: A computerized thermodynamic equilibrium calculation tool. Revision 1
Energy Technology Data Exchange (ETDEWEB)
Trowbridge, L.D.; Leitnaker, J.M. [Oak Ridge K-25 Site, TN (United States). Technical Analysis and Operations Div.
1995-07-01
SOLGAS, an early computer program for calculating equilibrium in a chemical system, has been made more user-friendly, and several ``bells and whistles`` have been added. The necessity to include elemental species has been eliminated. The input of large numbers of starting conditions has been automated. A revised spreadsheet-based format for entering data, including non-ideal binary and ternary mixtures, simplifies and reduces chances for error. Calculational errors by SOLGAS are flagged, and several programming errors are corrected. Auxiliary programs are available to assemble and partially automate plotting of large amounts of data. Thermodynamic input data can be changed on line. The program can be operated with or without a co-processor. Copies of the program, suitable for the IBM-PC or compatibles with at least 384 bytes of low RAM, are available from the authors. This user manual contains appendices with examples of the use of SOLGAS. These range from elementary examples, such as, the relationships among water, ice, and water vapor, to more complex systems: phase diagram calculation of UF{sub 4} and UF{sub 6} system; burning UF{sub 4} in fluorine; thermodynamic calculation of the Cl-F-O-H system; equilibria calculations in the CCl{sub 4}--CH{sub 3}OH system; and limitations applicable to aqueous solutions. An appendix also contains the source code.
Application of non-equilibrium thermodynamics to two-phase flows with a change of phase
International Nuclear Information System (INIS)
Delhaye, J.M.
1969-01-01
In this report we use the methods of non-equilibrium thermodynamics in two-phase flows. This paper follows a prior one in which we have studied the conservation laws and derived the general equations of two-phase flow. In the first part the basic ideas of thermodynamics of irreversible systems are given. We follow the classical point of view. The second part is concerned with the derivation of a closed set of equations for the two phase elementary volume model. In this model we assume that the elementary volume contains two phases and that it is possible to define a volumetric local concentration. To obtain the entropy balance we can choose either the reversibility of the barycentric motion or the reversibility of each phase. We adopt the last assumption and our derivation is the same as this of I.Prigogine and P. Mazur about the hydrodynamics of liquid helium. The scope of this work is not to find a general solution to the problems of two phase flows but to obtain a new set of equations which may be used to explain some characteristic phenomena of two-phase flow such as wave propagation or critical states. (author) [fr
Energy Technology Data Exchange (ETDEWEB)
Tan, I.A.W.; Ahmad, A.L. [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Hameed, B.H. [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)], E-mail: chbassim@eng.usm.my
2008-06-15
Adsorption isotherm and kinetics of methylene blue on activated carbon prepared from coconut husk were determined from batch tests. The effects of contact time (1-30 h), initial dye concentration (50-500 mg/l) and solution temperature (30-50 {sup o}C) were investigated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The equilibrium data were best represented by Langmuir isotherm model, showing maximum monolayer adsorption capacity of 434.78 mg/g. The kinetic data were fitted to pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and was found to follow closely the pseudo-second-order kinetic model. Thermodynamic parameters such as standard enthalpy ({delta}H{sup o}), standard entropy ({delta}S{sup o}) and standard free energy ({delta}G{sup o}) were evaluated. The adsorption interaction was found to be exothermic in nature. Coconut husk-based activated carbon was shown to be a promising adsorbent for removal of methylene blue from aqueous solutions.
International Nuclear Information System (INIS)
Bermudez Martinez, A.; Damiani, D.; Guzman Martinez, F.; Rodriguez Hoyos, O.; Rodriguez Manso, A.
2015-01-01
Cluster emission at pre-equilibrium stage, in heavy ion fusion reactions of 12 C and 16 O nuclei with 116 Sn, 208 Pb, 238 U are studied. the energy of the projectile nuclei was chosen at 0.25GeV, 0.5GeV and 1GeV. A cluster formation model is developed in order to calculate the cluster size. Thermodynamics of small systems was used in order to examine the cluster behavior inside the nuclear media. This model is based on considering two phases inside the compound nucleus, on one hand the nuclear media phase, and on the other hand the cluster itself. The cluster acts like an instability inside the compound nucleus, provoking an exchange of nucleons with the nuclear media through its surface. The processes were simulated using Monte Carlo methods. We obtained that the cluster emission probability shows great dependence on the cluster size. This project is aimed to implement cluster emission processes, during the pre-equilibrium stage, in the frame of CRISP code (Collaboration Rio-Sao Paulo). (Author)
Energy Technology Data Exchange (ETDEWEB)
Ayedh, H. M.; Svensson, B. G. [University of Oslo, Department of Physics/Center for Materials Science and Nanotechnology, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Nipoti, R. [Consiglio Nazionale delle Ricerche, Istituto di Microelettronica e Microsistemi, Sezione di Bologna (CNR-IMM of Bologna), I-40129 Bologna (Italy); Hallén, A. [Royal Institute of Technology, School of Information and Communication Technology (ICT), SE-164 40 Kista-Stockholm (Sweden)
2015-12-21
The carbon vacancy (V{sub C}) is a major point defect in high-purity 4H-SiC epitaxial layers limiting the minority charge carrier lifetime. In layers grown by chemical vapor deposition techniques, the V{sub C} concentration is typically in the range of 10{sup 12 }cm{sup −3}, and after device processing at temperatures approaching 2000 °C, it can be enhanced by several orders of magnitude. In the present study, both as-grown layers and a high-temperature processed one have been annealed at 1500 °C and the V{sub C} concentration is demonstrated to be strongly reduced, exhibiting a value of only a few times 10{sup 11 }cm{sup −3} as determined by deep-level transient spectroscopy measurements. The value is reached already after annealing times on the order of 1 h and is evidenced to reflect thermodynamic equilibrium under C-rich ambient conditions. The physical processes controlling the kinetics for establishment of the V{sub C} equilibrium are estimated to have an activation energy below ∼3 eV and both in-diffusion of carbon interstitials and out-diffusion of V{sub C}'s are discussed as candidates. This concept of V{sub C} elimination is flexible and readily integrated in a materials and device processing sequence.
Barsuk, Alexandr A.; Paladi, Florentin
2018-04-01
The dynamic behavior of thermodynamic system, described by one order parameter and one control parameter, in a small neighborhood of ordinary and bifurcation equilibrium values of the system parameters is studied. Using the general methods of investigating the branching (bifurcations) of solutions for nonlinear equations, we performed an exhaustive analysis of the order parameter dependences on the control parameter in a small vicinity of the equilibrium values of parameters, including the stability analysis of the equilibrium states, and the asymptotic behavior of the order parameter dependences on the control parameter (bifurcation diagrams). The peculiarities of the transition to an unstable state of the system are discussed, and the estimates of the transition time to the unstable state in the neighborhood of ordinary and bifurcation equilibrium values of parameters are given. The influence of an external field on the dynamic behavior of thermodynamic system is analyzed, and the peculiarities of the system dynamic behavior are discussed near the ordinary and bifurcation equilibrium values of parameters in the presence of external field. The dynamic process of magnetization of a ferromagnet is discussed by using the general methods of bifurcation and stability analysis presented in the paper.
Effect of heavy ion irradiation on thermodynamically equilibrium Zr-Excel alloy
Yu, Hongbing; Liang, Jianlie; Yao, Zhongwen; Kirk, Mark A.; Daymond, Mark R.
2017-05-01
The thermodynamically equilibrium state was achieved in a Zr-Sn-Nb-Mo alloy by long-term annealing at an intermediate temperature. The fcc intermetallic Zr(Mo, Nb)2 enriched with Fe was observed at the equilibrium state. In-situ 1 MeV Kr2+ heavy ion irradiation was performed in a TEM to study the stability of the intermetallic particles under irradiation and the effects of the intermetallic particle on the evolution of type dislocation loops at different temperatures from 80 to 550 °C. Chemi-STEM elemental maps were made at the same particles before and after irradiation up to 10 dpa. It was found that no elemental redistribution occurs at 200 °C and below. Selective depletion of Fe was observed from some precipitates under irradiation at higher temperatures. No change in the morphology of particles and no evidence showing a crystalline to amorphous transformation were observed at all irradiation temperatures. The formation of type dislocation loops was observed under irradiation at 80 and 200 °C, but not at 450 and 550 °C. The loops were non-uniformly distributed; a localized high density of type dislocation loops were observed near the second phase particles; we suggest that loop nucleation is favored as a result of the stress induced by the particles, rather than by elemental redistribution. The stability of the second phase particles and the formation of the type loops under heavy ion irradiation are discussed.
Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.
Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth
2010-04-14
Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed.
International Nuclear Information System (INIS)
Zanchini, E.
1988-01-01
The definition of energy, in thermodynamics, is dependent by starting operative definitions of the basic concepts of physics on which it rests, such as those of isolated systems, ambient of a system, separable system and set of separable states. Then the definition of energy is rigorously extended to open systems. The extension gives a clear physical meaning to the concept of energy difference between two states with arbitrary different compositions
Equilibrium properties of blackbody radiation with an ultraviolet energy cut-off
Mishra, Dheeraj Kumar; Chandra, Nitin; Vaibhav, Vinay
2017-10-01
We study various equilibrium thermodynamic properties of blackbody radiation (i.e. a photon gas) with an ultraviolet energy cut-off. We find that the energy density, specific heat etc. follow usual acoustic phonon dynamics as have been well studied by Debye. Other thermodynamic quantities like pressure, entropy etc. have also been calculated. The usual Stefan-Boltzmann law gets modified. We observe that the values of the thermodynamic quantities with the energy cut-off is lower than the corresponding values in the theory without any such scale. The phase-space measure is also expected to get modified for an exotic spacetime appearing at Planck scale, which in turn leads to the modification of Planck energy density distribution and the Wien's displacement law. We found that the non-perturbative nature of the thermodynamic quantities in the SR limit (for both unmodified and modified cases), due to nonanalyticity of the leading term, is a general feature of the theory accompanied with an ultraviolet energy cut-off. We have also discussed the possible modification in the case of Big Bang and the Stellar objects and have suggested a table top experiment for verification in effective low energy case.
Energy Technology Data Exchange (ETDEWEB)
Kul, Ali Riza [Yuzuncu Yil University, Faculty of Art and Science, Department of Chemistry, 65080 Van (Turkey); Koyuncu, Huelya, E-mail: hkoyuncu@yyu.edu.tr [Forensic Medicine Foundation, Felek Street No. 45, 06300 Kecioren, Ankara (Turkey)
2010-07-15
In this study, the adsorption kinetics, equilibrium and thermodynamics of Pb(II) ions on native (NB) and acid activated (AAB) bentonites were examined. The specific surface areas, pore size and pore-size distributions of the samples were fully characterized. The adsorption efficiency of Pb(II) onto the NB and AAB was increased with increasing temperature. The kinetics of adsorption of Pb(II) ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 16.51 and 13.66 kJ mol{sup -1} for NB and AAB, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations at different temperatures. R{sub L} separation factor for Langmuir and the n value for Freundlich isotherm show that Pb(II) ions are favorably adsorbed by NB and AAB. Thermodynamic quantities such as Gibbs free energy ({Delta}G), the enthalpy ({Delta}H) and the entropy change of sorption ({Delta}S) were determined as about -5.06, 10.29 and 0.017 kJ mol{sup -1} K{sup -1}, respectively for AAB. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously.
International Nuclear Information System (INIS)
Li, Guanchen; Al-Abbasi, Omar; Von Spakovsky, Michael R
2014-01-01
This paper outlines an atomistic-level framework for modeling the non-equilibrium behavior of chemically reactive systems. The framework called steepest- entropy-ascent quantum thermodynamics (SEA-QT) is based on the paradigm of intrinsic quantum thermodynamic (IQT), which is a theory that unifies quantum mechanics and thermodynamics into a single discipline with wide applications to the study of non-equilibrium phenomena at the atomistic level. SEA-QT is a novel approach for describing the state of chemically reactive systems as well as the kinetic and dynamic features of the reaction process without any assumptions of near-equilibrium states or weak-interactions with a reservoir or bath. Entropy generation is the basis of the dissipation which takes place internal to the system and is, thus, the driving force of the chemical reaction(s). The SEA-QT non-equilibrium model is able to provide detailed information during the reaction process, providing a picture of the changes occurring in key thermodynamic properties (e.g., the instantaneous species concentrations, entropy and entropy generation, reaction coordinate, chemical affinities, reaction rate, etc). As an illustration, the SEA-QT framework is applied to an atomistic-level chemically reactive system governed by the reaction mechanism F + H 2 ↔ FH + H
Trinh, T T; van Erp, T S; Bedeaux, D; Kjelstrup, S; Grande, C A
2015-03-28
Thermodynamic equilibrium for adsorption means that the chemical potential of gas and adsorbed phase are equal. A precise knowledge of the chemical potential is, however, often lacking, because the activity coefficient of the adsorbate is not known. Adsorption isotherms are therefore commonly fitted to ideal models such as the Langmuir, Sips or Henry models. We propose here a new procedure to find the activity coefficient and the equilibrium constant for adsorption which uses the thermodynamic factor. Instead of fitting the data to a model, we calculate the thermodynamic factor and use this to find first the activity coefficient. We show, using published molecular simulation data, how this procedure gives the thermodynamic equilibrium constant and enthalpies of adsorption for CO2(g) on graphite. We also use published experimental data to find similar thermodynamic properties of CO2(g) and of CH4(g) adsorbed on activated carbon. The procedure gives a higher accuracy in the determination of enthalpies of adsorption than ideal models do.
International Nuclear Information System (INIS)
Nevarez, M.; Bautista, R.G.
1976-01-01
The development of a thermodynamic equilibrium model to predict the cobalt distribution coefficient in the CoCl 2 -HCl-H 2 O-TBP system is described. The model makes use of the various aqueous phase cobaltous chloride complexes stoichiometric stability constants expressed as their degree of formation, their mechanism of extraction into the organic phase, and the equilibrium constant for the extraction reaction. The model was verified by the good agreement between the calculated cobalt distribution coefficients and those obtained experimentally both in the present study and published by other investigators. The optimum extraction of cobalt by the TBP occurred at an HCl equilibrium aqueous place concentration between 8.5 and 9.5M. The development of efficient procedures for the separation and concentration of important industrial metals from their aqueous solutions by liquid-liquid extraction has recently been given impetus by the realization of an impending shortage of energy and mineral resources. Liquid-liquid extraction is one of the few methods by which it is possible to quantitatively separate elements which are similar in properties. The use of liquid-liquid extraction to separate cobalt and nickel, which very frequently occur in nature together, is an important separation problem in nonferrous metallurgy. There is some fundamental information available in the chemical literature regarding the mechanism and equilibrium thermodynamic properties of selected liquid-liquid extraction systems. This research effort shows how this available information can be utilized to improve existing separation and concentration theory and technique. The development and application of a thermodynamic equilibrium model for describing the liquid-liquid extraction of cobaltous chloride from aqueous HCl solutions by tributyl phosphate (TBP) using experimental data obtained in this investigation and from the literature are presented
A NON-LOCAL THERMODYNAMIC EQUILIBRIUM ANALYSIS OF BORON ABUNDANCES IN METAL-POOR STARS
International Nuclear Information System (INIS)
Tan Kefeng; Shi Jianrong; Zhao Gang
2010-01-01
The non-local thermodynamic equilibrium (NLTE) line formation of neutral boron in the atmospheres of cool stars are investigated. Our results confirm that NLTE effects for the B I resonance lines, which are due to a combination of overionization and optical pumping effects, are most important for hot, metal-poor, and low-gravity stars; however, the amplitude of departures from local thermodynamic equilibrium (LTE) found by this work is smaller than that of previous studies. In addition, our calculation shows that the line formation of B I will get closer to LTE if the strength of collisions with neutral hydrogen increases, which is contrary to the result of previous studies. The NLTE line formation results are applied to the determination of boron abundances for a sample of 16 metal-poor stars with the method of spectrum synthesis of the B I 2497 A resonance lines using the archived HST/GHRS spectra. Beryllium and oxygen abundances are also determined for these stars with the published equivalent widths of the Be II 3131 A resonance and O I 7774 A triplet lines, respectively. The abundances of the nine stars which are not depleted in Be or B show that, no matter what the strength of collisions with neutral hydrogen may be, both Be and B increase with O quasilinearly in the logarithmic plane, which confirms the conclusions that Be and B are mainly produced by the primary process in the early Galaxy. The most noteworthy result of this work is that B increases with Fe or O at a very similar speed as, or a bit faster than, Be does, which is in accord with the theoretical models. The B/Be ratios remain almost constant over the metallicity range investigated here. Our average B/Be ratio falls in the interval [13 ± 4, 17 ± 4], which is consistent with the predictions of the spallation process. The contribution of B from the ν-process may be required if the 11 B/ 10 B isotopic ratios in metal-poor stars are the same as the meteoric value. An accurate measurement of the
International Nuclear Information System (INIS)
Qayoom, A.
2012-01-01
Summary: Batch adsorption of Cd (II) onto turmeric powder was conducted as a function of temperature. Nonlinear Langmuir, Freundlich, Dubinin-Radushkevish (D-R) and Temkin equilibrium models were employed. In addition to R 2, five different error functions were used to determine best fit equilibrium isotherm model. It was found that Freundlich isotherm model provided better fit for adsorption data at 298 and 303 K and Langmuir model was suitable for the experimental data obtained at 310 and 313 K. It was found that increase in temperature decreased maximum adsorption capacities, showing that the adsorption of Cd (II) onto turmeric powder is exothermic. Enthalpy values also confirmed the same trend. Entropy values were negative which means that randomness decreased on increasing temperature. Gibbs free energies were non spontaneous at all the temperatures studied. E values were in the range of 2.73-3.23 kJ mol/sup -1/ which indicated that adsorption mechanism is essentially physical. (author)
Effect of heavy ion irradiation on thermodynamically equilibrium Zr-Excel alloy
Energy Technology Data Exchange (ETDEWEB)
Yu, Hongbing [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Liang, Jianlie [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada); College of Science, Guangxi University for Nationalities, 188, East Da Xue Rd., Nanning, Guangxi, 530006 P.R.C (China); Yao, Zhongwen, E-mail: yaoz@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Kirk, Mark A. [Material Science Division Argonne National Laboratory, Argonne, IL 60439 (United States); Daymond, Mark R., E-mail: mark.daymond@queensu.ca [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, K7L 3N6 (Canada)
2017-05-15
The thermodynamically equilibrium state was achieved in a Zr-Sn-Nb-Mo alloy by long-term annealing at an intermediate temperature. The fcc intermetallic Zr(Mo, Nb){sub 2} enriched with Fe was observed at the equilibrium state. In-situ 1 MeV Kr{sup 2+} heavy ion irradiation was performed in a TEM to study the stability of the intermetallic particles under irradiation and the effects of the intermetallic particle on the evolution of
The effect of anisotropy on the thermodynamics of the interacting holographic dark energy model
Hossienkhani, H.; Jafari, A.; Fayaz, V.; Ramezani, A. H.
2018-02-01
By considering a holographic model for the dark energy in an anisotropic universe, the thermodynamics of a scheme of dark matter and dark energy interaction has been investigated. The results suggest that when holographic dark energy and dark matter evolve separately, each of them remains in thermodynamic equilibrium, therefore the interaction between them may be viewed as a stable thermal fluctuation that brings a logarithmic correction to the equilibrium entropy. Also the relation between the interaction term of the dark components and this thermal fluctuation has been obtained. Additionally, for a cosmological interaction as a free function, the anisotropy effects on the generalized second law of thermodynamics have been studied. By using the latest observational data on the holographic dark energy models as the unification of dark matter and dark energy, the observational constraints have been probed. To do this, we focus on observational determinations of the Hubble expansion rate H( z). Finally, we evaluate the anisotropy effects (although low) on various topics, such as the evolution of the statefinder diagnostic, the distance modulus and the spherical collapse from the holographic dark energy model and compare them with the results of the holographic dark energy of the Friedmann-Robertson-Walker and Λ CDM models.
Energy Technology Data Exchange (ETDEWEB)
Moog, Helge C. [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koeln (Germany); Regenspurg, Simona [GeoForschungsZentrum Potsdam (Germany); Voigt, Wolfgang [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Anorganische Chemie
2015-02-15
The concept for geothermal energy application for electricity generation can be differentiated into three compartments: In the geologic compartment cooled fluid is pressed into a porous or fractured rock formation, in the borehole compartment a hot fluid is pumped to the surface and back into the geothermal reservoir, in the aboveground facility the energy is extracted from the geothermal fluid by heat exchangers. Pressure and temperature changes influence the thermodynamic equilibrium of a system. The modeling of a geothermal system has therefore to consider besides the mass transport the heat transport and consequently changing solution compositions and the pressure/temperature effected chemical equilibrium. The GEODAT project is aimed to simulate the reactive mass transport in a geothermal reservoir in the North German basin (Gross Schoenebeck). The project was performed by the cooperation of three partners: Geoforschungsinstitut Potsdam, Bergakademie Freiberg and GRS.
Energy Technology Data Exchange (ETDEWEB)
Hussain, A.K.; Hussain, T.A.; Shahad, Haroun A.K. [Babylon Univ., Dept. of Mechanical Engineering, Babylon (Iraq)
2003-05-01
The problem of non-equilibrium heat conduction in a semi-infinite medium subjected to a step change in temperature is analyzed thermodynamically using the extended irreversible thermodynamic approach. The results show clearly the wave nature of the dimensionless temperature distribution, Stanton number and the dimensionless entropy change profiles. The non-equilibrium profiles approach the equilibrium profiles as the speed of wave propagation is increased. The results also show that the non-equilibrium temperature is higher than the equilibrium temperature but the difference decreases as the wave propagation speed increases. (Author)
Equilibrium, kinetic and thermodynamic studies on the adsorption of phenol onto graphene
Energy Technology Data Exchange (ETDEWEB)
Li, Yanhui, E-mail: liyanhui@tsinghua.org.cn [Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Du, Qiuju; Liu, Tonghao; Sun, Jiankun; Jiao, Yuqin [Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Xia, Yanzhi, E-mail: xiayzh@qdu.edu.cn [Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Xia, Linhua; Wang, Zonghua [Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Zhang, Wei; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai [Key Laboratory for Advanced Manufacturing by Material Processing Technology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)
2012-08-15
Graphical abstract: The effect of temperature on phenol adsorbed by graphene shows that the equilibrium adsorption capacity of phenol increases with the increase in temperature from 285 to 333 K. Increasing adsorption capacities with temperature indicates that the adsorption of phenol is controlled by an endothermic reaction. Highlights: ► The graphene has high phenol adsorption capacity. ► The graphene has a high specific surface area of 305 m{sup 2}/g. ► The adsorption capacity is high at acidic pH range. ► The graphene has rapid phenol adsorption rate. ► Phenol adsorption is a spontaneous and endothermic process. -- Abstract: Graphene, a new member of carbon family, has been prepared, characterized and used as adsorbent to remove phenol from aqueous solution. The effect parameters including pH, dosage, contact time, and temperature on the adsorption properties of phenol onto graphene were investigated. The results showed that the maximum adsorption capacity can reach 28.26 mg/g at the conditions of initial phenol concentration of 50 mg/L, pH 6.3 and 285 K. Adsorption data were well described by both Freundlich and Langmuir models. The kinetic study illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of phenol onto graphene was endothermic and spontaneous.
Equilibrium, kinetic and thermodynamic studies on the adsorption of phenol onto graphene
International Nuclear Information System (INIS)
Li, Yanhui; Du, Qiuju; Liu, Tonghao; Sun, Jiankun; Jiao, Yuqin; Xia, Yanzhi; Xia, Linhua; Wang, Zonghua; Zhang, Wei; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai
2012-01-01
Graphical abstract: The effect of temperature on phenol adsorbed by graphene shows that the equilibrium adsorption capacity of phenol increases with the increase in temperature from 285 to 333 K. Increasing adsorption capacities with temperature indicates that the adsorption of phenol is controlled by an endothermic reaction. Highlights: ► The graphene has high phenol adsorption capacity. ► The graphene has a high specific surface area of 305 m 2 /g. ► The adsorption capacity is high at acidic pH range. ► The graphene has rapid phenol adsorption rate. ► Phenol adsorption is a spontaneous and endothermic process. -- Abstract: Graphene, a new member of carbon family, has been prepared, characterized and used as adsorbent to remove phenol from aqueous solution. The effect parameters including pH, dosage, contact time, and temperature on the adsorption properties of phenol onto graphene were investigated. The results showed that the maximum adsorption capacity can reach 28.26 mg/g at the conditions of initial phenol concentration of 50 mg/L, pH 6.3 and 285 K. Adsorption data were well described by both Freundlich and Langmuir models. The kinetic study illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of phenol onto graphene was endothermic and spontaneous.
Modeling of thermodynamic non-equilibrium flows around cylinders and in channels
Sinha, Avick; Gopalakrishnan, Shiva
2017-11-01
Numerical simulations for two different types of flash-boiling flows, namely shear flow (flow through a de-Laval nozzle) and free shear flow (flow past a cylinder) are carried out in the present study. The Homogenous Relaxation Model (HRM) is used to model the thermodynamic non-equilibrium process. It was observed that the vaporization of the fluid stream, which was initially maintained at a sub-cooled state, originates at the nozzle throat. This is because the fluid accelerates at the vena-contracta and subsequently the pressure falls below the saturation vapor pressure, generating a two-phase mixture in the diverging section of the nozzle. The mass flow rate at the nozzle was found to decrease with the increase in fluid inlet temperature. A similar phenomenon also occurs for the free shear case due to boundary layer separation, causing a drop in pressure behind the cylinder. The mass fraction of vapor is maximum at rear end of the cylinder, where the size of the wake is highest. As the back pressure is reduced, severe flashing behavior was observed. The numerical simulations were validated against available experimental data. The authors gratefully acknowledge funding from the public-private partnership between DST, Confederation of Indian Industry and General Electric Pvt. Ltd.
A non-equilibrium thermodynamics model of reconstituted Ca(2+)-ATPase.
Waldeck, A R; van Dam, K; Berden, J; Kuchel, P W
1998-01-01
A non-equilibrium thermodynamics (NET) model describing the action of completely coupled or 'slipping' reconstituted Ca(2+)-ATPase is presented. Variation of the coupling stoichiometries with the magnitude of the electrochemical gradients, as the ATPase hydrolyzes ATP, is an indication of molecular slip. However, the Ca2+ and H+ membrane-leak conductances may also be a function of their respective gradients. Such non-ohmic leak typically yields 'flow-force' relationships that are similar to those that are obtained when the pump slips; hence, caution needs to be exercised when interpreting data of Ca(2+)-ATPase-mediated fluxes that display a non-linear dependence on the electrochemical proton (delta mu H) and/or calcium gradients (delta mu Ca). To address this issue, three experimentally verifiable relationships differentiating between membrane leak and enzymic slip were derived. First, by measuring delta mu H as a function of the rate of ATP hydrolysis by the enzyme. Second, by measuring the overall 'efficiency' of the pump as a function of delta mu H. Third, by measuring the proton ejection rate by the pump as a function of its ATP hydrolysis rate.
Biosorption of Cr(VI from AqueousSolution Using New Adsorbent: Equilibrium and Thermodynamic Study
Directory of Open Access Journals (Sweden)
Israa G. Zainal
2010-01-01
Full Text Available Biosorption is one such emerging technology which utilized naturally occurring waste materials to sequester heavy metals from polluted water. In the present study cinnamon was utilized for Cr(VI removal from aqueous solutions.It was found that a time of two hours was sufficient for sorption to attain equilibrium. The optimum pH was 2 for Cr(VI removal. Temprature has little influence on the biosorption process. The Cr(VI removal decreased with increase in temperature. The biosorption data was well fitted to Dubinin - Radushkevich (D-R, Freundlich and Tempkin adsorption isotherm models, although the correlation coefficient of Langmuir model was high but the calculated adsorption capacity did not agree with the experimental. The thermodynamic study reveals that the biosorption process is spontaneous and the spontaneity decreased with temperature increase and the process is exothermic accompanied by highly ordered adsorbate at the solid liquid interface. ΔH° values were negative and lie in the range of physical adsorption.
Searching the laws of thermodynamics in the Lorentz-invariant thermal energy propagation equation
International Nuclear Information System (INIS)
Szőllősi, Tibor; Márkus, Ferenc
2015-01-01
Highlights: • We study the laws of thermodynamics in a Lorentz-invariant Lagrangian model. • We calculate the canonical momenta and tensor. • We give the correspondents of the laws of thermodynamics in the model. • The developed theory is considered to be coherent with the laws of thermodynamics. - Abstract: In earlier works it has been shown that the Lorentz-invariant description of thermal energy transfer can be deduced from a Lagrangian description, by which the definition of a dynamic temperature is involved at the same time. It is also proved that this formulation includes the classical Fourier heat propagation as a natural limit. However, the relation of the elaborated theory to the basic laws of thermodynamics remained open. This connection is studied in details in the present paper. It is posted that though strictly speaking the model is meaningless in equilibrium and corresponds only to the non-equilibrium parts of the temperature, it respects the laws of thermodynamics and provides a way to transfer some form of them into the validity-area of the model
International Nuclear Information System (INIS)
Kennedy, L. John; Vijaya, J. Judith; Sekaran, G.; Kayalvizhi, K.
2007-01-01
Investigations were conducted in batch mode to study the adsorption behaviour of m-cresol on a porous carbon prepared from rice husk (RHAC) by varying the parameters such as agitation time, m-cresol concentration (50-300 mg/l), pH (2.5-10) and temperature (293-323 K). Studies showed that the adsorption decreased with increase in pH and temperature. The isotherm data were fitted to Langmuir, Freundlich, and Dubinin-Radushkevic (D-R) models. The kinetic models such as pseudo-first-order, pseudo-second-order and intraparticle diffusion models were selected to understand the reaction pathways and mechanism of adsorption process. The thermodynamic equilibrium coefficients obtained at different temperatures were used to evaluate the thermodynamic constants ΔG o , ΔH o and ΔS o . The sorption process was found to be exothermic in nature (ΔH o : -23.46 to -25.40 kJ/mol) with a decrease in entropy (ΔS o : -19.44 to -35.87 J/(mol K)). The negative value of Gibbs free energy, ΔG o indicates that the adsorption occurs via a spontaneous process. The decrease in the value of -ΔG o from 17.70 to 13.54 kJ/mol with increase in pH and temperature indicates that the adsorption of m-cresol onto activated carbon is less favourable at higher temperature and pH range. The influence of mesopore and a possible mechanism of adsorption is also suggested
Income- and energy-taxation for redistribution in general equilibrium
International Nuclear Information System (INIS)
FitzRoy, F.R.
1993-01-01
In a 3-factor General Equilibrium (GE)-model with a continuum of ability, the employed choose optimal labour supply, and equilibrium unemployment is determined by benefits funded by wage- and energy-taxes. Aggregate labour and the net wage may increase or decrease with taxation (and unemployment), and conditions for a reduction in redistributive wage-taxes to be Pareto-improving are derived. A small energy tax always raises the net wage, providing the wage tax is reduced to maintain constant employment and a balanced budget. High ability households prefer higher energy taxes when externalities are uniformly distributed and non-distorting. (author)
Energy Technology Data Exchange (ETDEWEB)
Fu Qingling; Deng Yali; Li Huishu; Liu Jie [Key Laboratory of Subtropical Agricultural Resource and Environment, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070 (China); Hu Hongqing, E-mail: hqhu@mail.hzau.edu.cn [Key Laboratory of Subtropical Agricultural Resource and Environment, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070 (China); Chen Shouwen [Key Laboratory of Subtropical Agricultural Resource and Environment, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070 (China); Sa Tongmin [Department of Agricultural Chemistry, College of Agriculture, Chungbuk National University, Cheongju, 361-763 (Korea, Republic of)
2009-02-01
The persistence of Bacillus thuringiensis (Bt) toxins in soil is further enhanced through association with soil particles. Such persistence may improve the effectiveness of controlling target pests, but impose a hazard to non-target organisms in soil ecosystems. In this study, the equilibrium adsorption of the Bt toxin by four clay minerals (montmorillonite, kaolinite, goethite, and silicon dioxide) was investigated, and the kinetic and thermodynamic parameters were calculated. The results showed that Bt toxin could be adsorbed easily by minerals, and the adsorption was much easier at low temperature than at high temperature at the initial concentration varying from 0 to 1000 mg L{sup -1}. The adsorption fitted well to both Langmuir and Freundlich isotherm models, but the Freundlich equation was more suitable. The pseudo-second-order (PSO) was the best application model to describe the adsorption kinetic. The adsorption process appeared to be controlled by chemical process, and the intra-particle diffusion was not the only rate-controlling step. The negative standard free energy ({Delta}{sub r}G{sub m}{sup {theta}}) values of the adsorption indicated that the adsorption of the Bt toxin by the minerals was spontaneous, and the changes of the standard enthalpy ({Delta}{sub r}H{sub m}{sup {theta}}) showed that the adsorption of the Bt toxin by montmorillonite was endothermic while the adsorption by the other three minerals was exothermic.
International Nuclear Information System (INIS)
Fu Qingling; Deng Yali; Li Huishu; Liu Jie; Hu Hongqing; Chen Shouwen; Sa Tongmin
2009-01-01
The persistence of Bacillus thuringiensis (Bt) toxins in soil is further enhanced through association with soil particles. Such persistence may improve the effectiveness of controlling target pests, but impose a hazard to non-target organisms in soil ecosystems. In this study, the equilibrium adsorption of the Bt toxin by four clay minerals (montmorillonite, kaolinite, goethite, and silicon dioxide) was investigated, and the kinetic and thermodynamic parameters were calculated. The results showed that Bt toxin could be adsorbed easily by minerals, and the adsorption was much easier at low temperature than at high temperature at the initial concentration varying from 0 to 1000 mg L -1 . The adsorption fitted well to both Langmuir and Freundlich isotherm models, but the Freundlich equation was more suitable. The pseudo-second-order (PSO) was the best application model to describe the adsorption kinetic. The adsorption process appeared to be controlled by chemical process, and the intra-particle diffusion was not the only rate-controlling step. The negative standard free energy (Δ r G m θ ) values of the adsorption indicated that the adsorption of the Bt toxin by the minerals was spontaneous, and the changes of the standard enthalpy (Δ r H m θ ) showed that the adsorption of the Bt toxin by montmorillonite was endothermic while the adsorption by the other three minerals was exothermic.
Energy Technology Data Exchange (ETDEWEB)
Senturk, Hasan Basri; Ozdes, Duygu; Gundogdu, Ali; Duran, Celal [Department of Chemistry, Karadeniz Technical University, Faculty of Arts and Sciences, 61080 Trabzon (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Department of Chemistry, Erciyes University, Faculty of Arts and Sciences, 38039 Kayseri (Turkey)
2009-12-15
A natural bentonite modified with a cationic surfactant, cetyl trimethylammonium bromide (CTAB), was used as an adsorbent for removal of phenol from aqueous solutions. The natural and modified bentonites (organobentonite) were characterized with some instrumental techniques (FTIR, XRD and SEM). Adsorption studies were performed in a batch system, and the effects of various experimental parameters such as solution pH, contact time, initial phenol concentration, organobentonite concentration, and temperature, etc. were evaluated upon the phenol adsorption onto organobentonite. Maximum phenol removal was observed at pH 9.0. Equilibrium was attained after contact of 1 h only. The adsorption isotherms were described by Langmuir and Freundlich isotherm models, and both model fitted well. The monolayer adsorption capacity of organobentonite was found to be 333 mg g{sup -1}. Desorption of phenol from the loaded adsorbent was achieved by using 20% acetone solution. The kinetic studies indicated that the adsorption process was best described by the pseudo-second-order kinetics (R{sup 2} > 0.99). Thermodynamic parameters including the Gibbs free energy ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}), and entropy ({Delta}S{sup o}) were also calculated. These parameters indicated that adsorption of phenol onto organobentonite was feasible, spontaneous and exothermic in the temperature range of 0-40 {sup o}C.
International Nuclear Information System (INIS)
Senturk, Hasan Basri; Ozdes, Duygu; Gundogdu, Ali; Duran, Celal; Soylak, Mustafa
2009-01-01
A natural bentonite modified with a cationic surfactant, cetyl trimethylammonium bromide (CTAB), was used as an adsorbent for removal of phenol from aqueous solutions. The natural and modified bentonites (organobentonite) were characterized with some instrumental techniques (FTIR, XRD and SEM). Adsorption studies were performed in a batch system, and the effects of various experimental parameters such as solution pH, contact time, initial phenol concentration, organobentonite concentration, and temperature, etc. were evaluated upon the phenol adsorption onto organobentonite. Maximum phenol removal was observed at pH 9.0. Equilibrium was attained after contact of 1 h only. The adsorption isotherms were described by Langmuir and Freundlich isotherm models, and both model fitted well. The monolayer adsorption capacity of organobentonite was found to be 333 mg g -1 . Desorption of phenol from the loaded adsorbent was achieved by using 20% acetone solution. The kinetic studies indicated that the adsorption process was best described by the pseudo-second-order kinetics (R 2 > 0.99). Thermodynamic parameters including the Gibbs free energy (ΔG o ), enthalpy (ΔH o ), and entropy (ΔS o ) were also calculated. These parameters indicated that adsorption of phenol onto organobentonite was feasible, spontaneous and exothermic in the temperature range of 0-40 o C.
International Nuclear Information System (INIS)
Snyder, S.C.; Lassahn, G.D.; Reynolds, L.D.
1993-01-01
Radial profiles of gas temperature, electron temperature, and electron density were measured in a free-burning atmospheric-pressure argon arc-discharge plasma using line-shape analysis of scattered laser light. This method yields gas temperature, electron temperature, and electron density directly, with no reliance on the assumption of local thermodynamic equilibrium (LTE). Our results show a significant departure from LTE in the center of the discharge, contrary to expectations
International Nuclear Information System (INIS)
Hwang, Jeong Ui; Jang, Jong Jae; Jee, Jong Gi
1987-01-01
The contents of this book are thermodynamics on the law of thermodynamics, classical thermodynamics and molecule thermodynamics, basics of molecule thermodynamics, molecule and assembly partition function, molecule partition function, classical molecule partition function, thermodynamics function for ideal assembly in fixed system, thermodynamics function for ideal assembly in running system, Maxwell-Boltzmann's law of distribution, chemical equilibrium like calculation of equilibrium constant and theory of absolute reaction rate.
Directory of Open Access Journals (Sweden)
P. K. Baskaran
2011-01-01
Full Text Available The ability of zea mays dust carbon to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Thermodynamic parameters such as ΔH°,ΔS° and ΔG°, were calculated from the slope and intercept of the linear plots. Analysis of adsorption results obtained at 303, 313, 323 and 333 K showed that the adsorption pattern on zea mays dust carbon seems to follow the Langmuir and Freundlich. The numerical values of sorption free energy indicate physical adsorption. The kinetic data indicated an intra-particle diffusion process with sorption being first order. The concentration of malachite green oxalate was measured before and after adsorption by using UV-visible spectrophotometer.
Chakraborty, Sagnik; Chowdhury, Shamik; Saha, Papita Das
2012-06-01
Biosorption performance of pineapple leaf powder (PLP) for removal of crystal violet (CV) from its aqueous solutions was investigated. To this end, the influence of operational parameters such as pH, biosorbent dose, initial dye concentration and temperature were studied employing a batch experimental setup. The biosorption process followed the Langmuir isotherm model with high correlation coefficients ( R 2 > 0.99) at different temperatures. The maximum monolayer biosorption capacity was found to be 78.22 mg g-1 at 293 K. The kinetic data conformed to the pseudo-second-order kinetic model. The activation energy of the system was calculated as 58.96 kJ mol- 1 , indicating chemisorption nature of the ongoing biosorption process. A thermodynamic study showed spontaneous and exothermic nature of the biosorption process. Owing to its low cost and high dye uptake capacity, PLP has potential for application as biosorbent for removal of CV from aqueous solutions.
Energy Technology Data Exchange (ETDEWEB)
Kim, Ji-Su; Kim, Yeong-Cheol [Korea University of Technology and Education, Cheonan (Korea, Republic of)
2017-01-15
We investigated the equilibrium crystal shape of BaZrO{sub 3} and the space charge formation in an O-terminated (011) surface by using ab-initio thermodynamics. Twenty-two low-indexed (001), (011), and (111) surfaces were calculated to analyze their surface Gibbs-free energy under the stable condition of BaZrO{sub 3}. Based on the Gibbs-Wulff theorem, the equilibrium crystal shape of BaZrO{sub 3} changed from cubic to decaoctahedral with decreasing Ba chemical potential. The dominant facets of BaZrO{sub 3} were {001} and {011}, which were well consistent with experimental observations. The space charge formation in the (011) surface was evaluated using the space-charge model. We found that the (011) surface was even more resistive than the (001) surface.
Sivarajasekar, N.; Baskar, R.; Ragu, T.; Sarika, K.; Preethi, N.; Radhika, T.
2017-07-01
The immature Gossypium hirsutum seeds—an agricultural waste was converted into a novel adsorbent and its effectiveness for cationic dyes removal was discussed in this study. Characterization revealed that sulfuric acid activated waste Gossypium hirsutum seed (WGSAB) contains surface area 496 m2 g-1. The ability of WGSAB to adsorb basic red 2 (BR2) and basic violet 3 (BV3) from aqueous solutions has been studied. Batch adsorption studies were carried out at different initial dye concentrations (100-300 mg l-1), contact time (1-5 h), pH (2-12) and temperature (293-323 K) to understand the adsorption mechanism. Adsorption data were modeled using Langmuir, Freundlich and Toth adsorption isotherms. Equilibrium data of the adsorption process fitted very well to the Toth model for both dyes. The Langmuir maximum adsorption capacity was 66.69 mg g-1 for BV3 and 50.11 mg g-1 for BR2 at optimum conditions. The near unity value of Toth isotherm constant (BR2: 0.999 and BV3: 1.0) indicates that WGSAB surface is heterogeneous in nature. The maximum adsorption capacity predicted by Toth isotherm of BV3 (66.699 mg g-1) is higher than BR2 (50.310 mg g-1). The kinetic investigation revealed that the BR2 and BV3 were chemisorbed on WGSAB surface following Avrami fractional order kinetics. Further, the fractional order and rate constant values are almost similar for every concentration in both the dyes. The thermodynamic parameters such as Δ H 0, Δ S 0 and Δ G 0 were evaluated. The dye adsorption process was found to be spontaneous and endothermic for the two dyes. Regeneration of WGSAB exhausted by the two dyes could be possible via acetic acid as elutant.
International Nuclear Information System (INIS)
Pinto, Leandro F.; Segalen da Silva, Diogo Italo; Rosa da Silva, Fabiano; Ramos, Luiz P.; Ndiaye, Papa M.; Corazza, Marcos L.
2012-01-01
Highlights: → We measured phase behavior for the system involving {CO 2 + biodiesel + methanol}. → The saturation pressures were obtained using a variable-volume view cell. → The experimental data were modeled using PR-vdW2 and PR-WS equations of state. - Abstract: The main objective of this work was to investigate the high pressure phase behavior of the binary systems {CO 2 (1) + methanol(2)} and {CO 2 (1) + soybean methyl esters (biodiesel)(2)} and the ternary system {CO 2 (1) + biodiesel(2) + methanol(3)} were determined. Biodiesel was produced from soybean oil, purified, characterized and used in this work. The static synthetic method, using a variable-volume view cell, was employed to obtain the experimental data in the temperature range of (303.15 to 343.15) K and pressures up to 21 MPa. The mole fractions of carbon dioxide were varied according to the systems as follows: (0.2383 to 0.8666) for the binary system {CO 2 (1) + methanol(2)}; (0.4201 to 0.9931) for the binary system {CO 2 (1) + biodiesel(2)}; (0.4864 to 0.9767) for the ternary system {CO 2 (1) + biodiesel(2) + methanol(3)} with a biodiesel to methanol molar ratio of (1:3); and (0.3732 to 0.9630) for the system {CO 2 + biodiesel + methanol} with a biodiesel to methanol molar ratio of (8:1). For these systems, (vapor + liquid), (liquid + liquid), (vapor + liquid + liquid) transitions were observed. The phase equilibrium data obtained for the systems were modeled using the Peng-Robinson equation of state with the classical van der Waals (PR-vdW2) and Wong-Sandler (PR-WS) mixing rules. Both thermodynamic models were able to satisfactorily correlate the phase behavior of the systems investigated and the PR-WS presented the best performance.
Experimental benchmark of non-local-thermodynamic-equilibrium plasma atomic physics codes
International Nuclear Information System (INIS)
Nagels-Silvert, V.
2004-09-01
The main purpose of this thesis is to get experimental data for the testing and validation of atomic physics codes dealing with non-local-thermodynamical-equilibrium plasmas. The first part is dedicated to the spectroscopic study of xenon and krypton plasmas that have been produced by a nanosecond laser pulse interacting with a gas jet. A Thomson scattering diagnostic has allowed us to measure independently plasma parameters such as electron temperature, electron density and the average ionisation state. We have obtained time integrated spectra in the range between 5 and 10 angstroms. We have identified about one hundred xenon rays between 8.6 and 9.6 angstroms via the use of the Relac code. We have discovered unknown rays for the krypton between 5.2 and 7.5 angstroms. In a second experiment we have extended the wavelength range to the X UV domain. The Averroes/Transpec code has been tested in the ranges from 9 to 15 angstroms and from 10 to 130 angstroms, the first range has been well reproduced while the second range requires a more complex data analysis. The second part is dedicated to the spectroscopic study of aluminium, selenium and samarium plasmas in femtosecond operating rate. We have designed an interferometry diagnostic in the frequency domain that has allowed us to measure the expanding speed of the target's backside. Via the use of an adequate isothermal model this parameter has led us to know the plasma electron temperature. Spectra and emission times of various rays from the aluminium and selenium plasmas have been computed satisfactorily with the Averroes/Transpec code coupled with Film and Multif hydrodynamical codes. (A.C.)
Energy flow in non-equilibrium conformal field theory
Bernard, Denis; Doyon, Benjamin
2012-09-01
We study the energy current and its fluctuations in quantum gapless 1d systems far from equilibrium modeled by conformal field theory, where two separated halves are prepared at distinct temperatures and glued together at a point contact. We prove that these systems converge towards steady states, and give a general description of such non-equilibrium steady states in terms of quantum field theory data. We compute the large deviation function, also called the full counting statistics, of energy transfer through the contact. These are universal and satisfy fluctuation relations. We provide a simple representation of these quantum fluctuations in terms of classical Poisson processes whose intensities are proportional to Boltzmann weights.
Calculation of thermodynamic equilibrium between bcc disordered solid solutions U and Mo
International Nuclear Information System (INIS)
Alonso, Paula R.; Rubiolo, Gerardo H.
2003-01-01
There is actually an interest to develop a new fuel with higher density for research reactors. Fuel plates would be obtained by dispersion, a method that requires both a very dense fuel dispersant (>15.0 g U/cm 3 ) and a very high volume loading of the dispersant (>55%). Dispersants based in gamma (BCC) stabilized uranium alloys are being investigated, as they are able to reach uranium densities of 17.0 g U/cm 3 . Among them, we focus in U(Mo) bcc solid solutions with the addition of ternary elements to stabilize gamma phase. Transition metals, 4d and 5d, of groups VII and VIII are good candidates for the ternary alloy U - Mo - X. Their relative power to stabilize gamma phase seems to be in close relation with bonding energies between atoms in the alloy. A first approach to the calculation of these energies has been performed by the semi empiric method of Miedema where only bonds between pairs are considered, neglecting ternary and quaternary bonds. There is also a lack of information concerning solubilities of the ternary elements in the ternary cubic phase. In this work we aim to calculate bonding energies between atoms in the alloy using a cluster expansion of the formation energy (T=0 K) of a series of bcc ordered compounds in the systems U-Mo-X. Then the calculation of the equilibrium phase diagram by the Cluster Variation Method will be done (CVM). We show here the first part of the investigation devoted to calculation of phases equilibria in the U Mo system Formation energies of the ordered compounds were obtained by the first principles methods TB-LMTO-ASA and FP-LAPW. Another set of bonding energies was calculated in order to fit the known experimental diagram and new formation energies for the ordered compounds were derived from them. Discrepancies between both sets are discussed. (author)
Dong, Yitong; Qiao, Tian; Kim, Doyun; Parobek, David; Rossi, Daniel; Son, Dong Hee
2018-05-09
Cesium lead halide (CsPbX 3 ) nanocrystals have emerged as a new family of materials that can outperform the existing semiconductor nanocrystals due to their superb optical and charge-transport properties. However, the lack of a robust method for producing quantum dots with controlled size and high ensemble uniformity has been one of the major obstacles in exploring the useful properties of excitons in zero-dimensional nanostructures of CsPbX 3 . Here, we report a new synthesis approach that enables the precise control of the size based on the equilibrium rather than kinetics, producing CsPbX 3 quantum dots nearly free of heterogeneous broadening in their exciton luminescence. The high level of size control and ensemble uniformity achieved here will open the door to harnessing the benefits of excitons in CsPbX 3 quantum dots for photonic and energy-harvesting applications.
Grossman, B.; Cinella, P.
1988-01-01
A finite-volume method for the numerical computation of flows with nonequilibrium thermodynamics and chemistry is presented. A thermodynamic model is described which simplifies the coupling between the chemistry and thermodynamics and also results in the retention of the homogeneity property of the Euler equations (including all the species continuity and vibrational energy conservation equations). Flux-splitting procedures are developed for the fully coupled equations involving fluid dynamics, chemical production and thermodynamic relaxation processes. New forms of flux-vector split and flux-difference split algorithms are embodied in a fully coupled, implicit, large-block structure, including all the species conservation and energy production equations. Several numerical examples are presented, including high-temperature shock tube and nozzle flows. The methodology is compared to other existing techniques, including spectral and central-differenced procedures, and favorable comparisons are shown regarding accuracy, shock-capturing and convergence rates.
Energy equation for the analysis of magnetization relaxation to equilibrium
Energy Technology Data Exchange (ETDEWEB)
Bertotti, G. [IEN Galileo Ferraris, Materials Department, Strada delle Cacce, 91, I-10135 Torino (Italy)]. E-mail: bertotti@ien.it; Bonin, R. [Dipartimento di Fisica, Politecnico di Torino, I-10129 Torino (Italy); Magni, A. [IEN Galileo Ferraris, Materials Department, Strada delle Cacce, 91, I-10135 Torino (Italy); Mayergoyz, I.D. [Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland, 20742 (United States); Serpico, C. [Dipartimento di Ingegneria Elettrica, Universita di Napoli ' Federico II' , I-80125 Naples (Italy)
2005-02-01
Magnetization relaxation starting from a generic non-equilibrium state is analytically described. An equation for the energy decay is obtained. On this basis, an approximate expression for the magnetization motion during the ringing process is obtained in terms of Jacobi elliptic functions with time-dependent parameters.
Energy equation for the analysis of magnetization relaxation to equilibrium
International Nuclear Information System (INIS)
Bertotti, G.; Bonin, R.; Magni, A.; Mayergoyz, I.D.; Serpico, C.
2005-01-01
Magnetization relaxation starting from a generic non-equilibrium state is analytically described. An equation for the energy decay is obtained. On this basis, an approximate expression for the magnetization motion during the ringing process is obtained in terms of Jacobi elliptic functions with time-dependent parameters
International Nuclear Information System (INIS)
Singh, Jayram; Singh, N.B.
2015-01-01
Graphical abstract: The phase diagram of (m-dinitrobenzene + vanillin) system. - Highlights: • (Thaw + melt) method has shown that (m-dinitrobenzene + vanillin) system forms simple eutectic type phase diagram. • Excess thermodynamic functions showed that eutectic mixture is non-ideal. • The flexural strength measurements have shown that in eutectic mixture, crystallization occurs in an ordered way. - Abstract: The phase diagram of (m-dinitrobenzene + vanillin) system has been studied by the thaw melt method and an eutectic type phase diagram was obtained. The linear velocities of crystallization of the parent components and the eutectic mixture were determined. The enthalpy of fusion of the components and the eutectic mixture were determined using the differential scanning calorimetric technique. Excess Gibbs energy, excess entropy, excess enthalpy of mixing, and interfacial energy have been calculated. FTIR spectroscopic studies and flexural strength measurements were also made. The results have shown that the eutectic is a non-ideal mixture of the two components. On the basis of Jackson’s roughness parameter, it is predicted that the eutectic has faceted morphology
Hütter, Markus; Brader, Joseph M
2009-06-07
We examine the origins of nonlocality in a nonisothermal hydrodynamic formulation of a one-component fluid of particles that exhibit long-range correlations, e.g., due to a spherically symmetric, long-range interaction potential. In order to furnish the continuum modeling with physical understanding of the microscopic interactions and dynamics, we make use of systematic coarse graining from the microscopic to the continuum level. We thus arrive at a thermodynamically admissible and closed set of evolution equations for the densities of momentum, mass, and internal energy. From the consideration of an illustrative special case, the following main conclusions emerge. There are two different source terms in the momentum balance. The first is a body force, which in special circumstances can be related to the functional derivative of a nonlocal Helmholtz free energy density with respect to the mass density. The second source term is proportional to the temperature gradient, multiplied by the nonlocal entropy density. These two source terms combine into a pressure gradient only in the absence of long-range effects. In the irreversible contributions to the time evolution, the nonlocal contributions arise since the self-correlations of the stress tensor and heat flux, respectively, are nonlocal as a result of the microscopic nonlocal correlations. Finally, we point out specific points that warrant further discussions.
International Nuclear Information System (INIS)
Prevosto, L.; Mancinelli, B.; Artana, G.; Kelly, H.
2011-01-01
A two-wavelength quantitative Schlieren technique that allows inferring the electron and gas densities of axisymmetric arc plasmas without imposing any assumption regarding statistical equilibrium models is reported. This technique was applied to the study of local thermodynamic equilibrium (LTE) departures within the core of a 30 A high-energy density cutting arc. In order to derive the electron and heavy particle temperatures from the inferred density profiles, a generalized two-temperature Saha equation together with the plasma equation of state and the quasineutrality condition were employed. Factors such as arc fluctuations that influence the accuracy of the measurements and the validity of the assumptions used to derive the plasma species temperature were considered. Significant deviations from chemical equilibrium as well as kinetic equilibrium were found at elevated electron temperatures and gas densities toward the arc core edge. An electron temperature profile nearly constant through the arc core with a value of about 14000-15000 K, well decoupled from the heavy particle temperature of about 1500 K at the arc core edge, was inferred.
International Nuclear Information System (INIS)
Lima da Silva, Aline; Heck, Nestor Cesar
2003-01-01
Equilibrium concentrations are traditionally calculated with the help of equilibrium constant equations from selected reactions. This procedure, however, is only useful for simpler problems. Analysis of the equilibrium state in a multicomponent and multiphase system necessarily involves solution of several simultaneous equations, and, as the number of system components grows, the required computation becomes more complex and tedious. A more direct and general method for solving the problem is the direct minimization of the Gibbs energy function. The solution for the nonlinear problem consists in minimizing the objective function (Gibbs energy of the system) subjected to the constraints of the elemental mass-balance. To solve it, usually a computer code is developed, which requires considerable testing and debugging efforts. In this work, a simple method to predict equilibrium composition in multicomponent systems is presented, which makes use of an electronic spreadsheet. The ability to carry out these calculations within a spreadsheet environment shows several advantages. First, spreadsheets are available 'universally' on nearly all personal computers. Second, the input and output capabilities of spreadsheets can be effectively used to monitor calculated results. Third, no additional systems or programs need to be learned. In this way, spreadsheets can be as suitable in computing equilibrium concentrations as well as to be used as teaching and learning aids. This work describes, therefore, the use of the Solver tool, contained in the Microsoft Excel spreadsheet package, on computing equilibrium concentrations in a multicomponent system, by the method of direct Gibbs energy minimization. The four phases Fe-Cr-O-C-Ni system is used as an example to illustrate the method proposed. The pure stoichiometric phases considered in equilibrium calculations are: Cr 2 O 3 (s) and FeO C r 2 O 3 (s). The atmosphere consists of O 2 , CO e CO 2 constituents. The liquid iron
Equilibrium charge state distributions of high energy heavy ions
International Nuclear Information System (INIS)
Clark, R.B.; Grant, I.S.; King, R.; Eastham, D.A.; Joy, T.
1976-01-01
Equilibrium charge state fractions have been measured for N, O, Ne, S, Ar and Kr ions at 1.04 MeV/nucleon after passing through various stripping materials. Further data were obtained at higher energy for S ions (4.12 MeV/nucleon) and Ar ions (4.12 and 9.6 MeV/nucleon). The mean charge fractions can be fitted to universal curves for both solid and gaseous strippers. Measurements of the equilibrium fraction of krypton ions at 1.04 MeV/nucleon passing through heavy vapours have shown that a higher average charge state is obtained than for lighter gaseous strippers. (Auth.)
Mongiovì, Maria Stella; Jou, David; Sciacca, Michele
2018-01-01
This review paper puts together some results concerning non equilibrium thermodynamics and heat transport properties of superfluid He II. A one-fluid extended model of superfluid helium, which considers heat flux as an additional independent variable, is presented, its microscopic bases are analyzed, and compared with the well known two-fluid model. In laminar situations, the fundamental fields are density, velocity, absolute temperature, and heat flux. Such a theory is able to describe the thermomechanical phenomena, the propagation of two sounds in liquid helium, and of fourth sound in superleak. It also leads in a natural way to a two-fluid model on purely macroscopical grounds and allows a small amount of entropy associated with the superfluid component. Other important features of liquid He II arise in rotating situations and in superfluid turbulence, both characterized by the presence of quantized vortices (thin vortex lines whose circulation is restricted by a quantum condition). Such vortices have a deep influence on the transport properties of superfluid helium, as they increase very much its thermal resistance. Thus, heat flux influences the vortices which, in turn, modify the heat flux. The dynamics of vortex lines is the central topic in turbulent superfluid helium. The model is generalized to take into account the vortices in different cases of physical interest: rotating superfluids, counterflow superfluid turbulence, combined counterflow and rotation, and mass flow in addition to heat flow. To do this, the averaged vortex line density per unit volume L, is introduced and its dynamical equations are considered. Linear and non-linear evolution equations for L are written for homogeneous and inhomogeneous, isotropic and anisotropic situations. Several physical experiments are analyzed and the influence of vortices on the effective thermal conductivity of turbulent superfluid helium is found. Transitions from laminar to turbulent flows, from diffusive to
Thermodynamic performance assessment of wind energy systems: An application
International Nuclear Information System (INIS)
Redha, Adel Mohammed; Dincer, Ibrahim; Gadalla, Mohamed
2011-01-01
In this paper, the performance of wind energy system is assessed thermodynamically, from resource and technology perspectives. The thermodynamic characteristics of wind through energy and exergy analyses are considered and both energetic and exergetic efficiencies are studied. Wind speed is affected by air temperature and pressure and has a subsequent effect on wind turbine performance based on wind reference temperature and Bernoulli's equation. VESTAS V52 wind turbine is selected for (Sharjah/UAE). Energy and exergy efficiency equations for wind energy systems are further developed for practical applications. The results show that there are noticeable differences between energy and exergy efficiencies and that exergetic efficiency reflects the right/actual performance. Finally, exergy analysis has been proven to be the right tool used in design, simulation, and performance evaluation of all renewable energy systems. -- Highlights: → In this research the performance of wind energy system is assessed thermodynamically, from resource and technology perspectives. → Energy and exergy equations for wind energy systems are further developed for practical applications. → Thermodynamic characteristics of wind turbine systems through energetic and exergetic efficiencies are evaluated from January till March 2010. → Exergy efficiency describes the system irreversibility and the minimum irreversibility exists when the wind speed reaches 11 m/s. → The power production during March was about 17% higher than the month of February and 66% higher than January.
Konggidinata, Mas Iwan; Chao, Bing; Lian, Qiyu; Subramaniam, Ramalingam; Zappi, Mark; Gang, Daniel Dianchen
2017-08-15
Chemical and petrochemical industries produce substantial amounts of wastewater everyday. This wastewater contains organic pollutants such as benzene, toluene, ethylbenzene and xylenes (BTEX) that are toxic to human and aquatic life. Ordered Mesoporous Carbon (OMC), the adsorbent that possesses the characteristics of an ideal adsorbent was investigated to understand its properties and suitability for BTEX removal. Adsorption isotherms, adsorption kinetics, the effects of initial BTEX concentrations and temperatures on the adsorption process were studied. The OMCs were characterized using surface area and pore size analyzer, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR). The results suggested that the Langmuir Isotherm and Pseudo-Second-Order Models described the experimental data well. The thermodynamic parameters, Gibbs free energy (ΔG°), the enthalpy change (ΔH°) and the entropy change (ΔS°) of adsorption indicated that the adsorption processes were physical, endothermic, and spontaneous. In addition, OMC had 27% higher overall adsorption capacities compared to granular activated carbon (GAC). Copyright © 2017 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Wassim M. Haddad
2013-05-01
Full Text Available In this paper, we combine the two universalisms of thermodynamics and dynamical systems theory to develop a dynamical system formalism for classical thermodynamics. Specifically, using a compartmental dynamical system energy flow model involving heat flow, work energy, and chemical reactions, we develop a state-space dynamical system model that captures the key aspects of thermodynamics, including its fundamental laws. In addition, we show that our thermodynamically consistent dynamical system model is globally semistable with system states converging to a state of temperature equipartition. Furthermore, in the presence of chemical reactions, we use the law of mass-action and the notion of chemical potential to show that the dynamic system states converge to a state of temperature equipartition and zero affinity corresponding to a state of chemical equilibrium.
Thermodynamical Aspects of Modified Holographic Dark Energy Model
International Nuclear Information System (INIS)
Li Hui; Zhang Yi
2014-01-01
We investigate the unified first law and the generalized second law in a modified holographic dark energy model. The thermodynamical analysis on the apparent horizon can work and the corresponding entropy formula is extracted from the systematic algorithm. The entropy correction term depends on the extra-dimension number of the brane as expected, but the interplay between the correction term and the extra dimensions is more complicated. With the unified first law of thermodynamics well-founded, the generalized second law of thermodynamics is discussed and it is found that the second law can be violated in certain circumstances. Particularly, if the number of the extra dimensions is larger than one, the generalized law of thermodynamics is always satisfied; otherwise, the validity of the second law can only be guaranteed with the Hubble radius greatly smaller than the crossover scale r c of the 5-dimensional DGP model. (geophysics, astronomy, and astrophysics)
Nosonovsky, Michael
2013-01-01
Many scientists and engineers do not realize that, under certain conditions, friction can lead to the formation of new structures at the interface, including in situ tribofilms and various patterns. In turn, these structures-usually formed by destabilization of the stationary sliding regime-can lead to the reduction of friction and wear. Friction-Induced Vibrations and Self-Organization: Mechanics and Non-Equilibrium Thermodynamics of Sliding Contact combines the mechanical and thermodynamic methods in tribology, thus extending the field of mechanical friction-induced vibrations to non-mechanical instabilities and self-organization processes at the frictional interface. The book also relates friction-induced self-organization to novel biomimetic materials, such as self-lubricating, self-cleaning, and self-healing materials. Explore Friction from a Different Angle-as a Fundamental Force of Nature The book begins with an exploration of friction as a fundamental force of nature throughout the history of science....
Energy Technology Data Exchange (ETDEWEB)
Karimaian, Kamal Aldin [Department of Environmental Health Engineering, Faculty of Health, Kurdistan University of Medical Sciences, Sannandaj (Iran, Islamic Republic of); Amrane, Abdeltif [Ecole Nationale Supérieure de Chimie de Rennes, Université Rennes 1, CNRS, UMR 6226, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Kazemian, Hossein [Department of Chemical and Biochemical Engineering, Western University, London, ON, Canada N6A 5B9 (Canada); Panahi, Reza [Department of Biotechnology, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Zarrabi, Mansur, E-mail: mansor62@gmail.com [Department of Environmental Health Engineering, Faculty of Health, Alborz University of Medical Sciences, Karaj (Iran, Islamic Republic of)
2013-11-01
Natural and Mg{sup 2+} modified pumice were used for the removal of phosphorous. The adsorbents were characterized using XRF, XRD, SEM and FTIR instrumental techniques. In the optimal conditions, namely at equilibrium time (30 min), for a phosphorus concentration of 15 mg/L and pH 6, 69 and 97% phosphorus removals were achieved using 10 g/L of natural and modified pumice adsorbents, respectively. Maximum adsorption capacities were 11.88 and 17.71 mg/g by natural and modified pumice, respectively. Pseudo-second order kinetic model was the most relevant to describe the kinetic of phosphorus adsorption. External mass transfer coefficient decreased for increasing phosphorous concentration and film diffusion was found to be the rate-controlling step. Only a very low dissolution of the adsorbent was observed, leading to a low increase in conductivity and turbidity. Removal efficiency decreased for increasing ionic strength. It also decreased in the presence of competing ions; however modified pumice remained effective, since 67% of phosphorus was removed, versus only 17% for the natural pumice. The efficiency of the modified pumice was confirmed during the regeneration tests, since 96% regeneration yield was obtained after 510 min experiment, while only 22% was observed for the raw pumice.
International Nuclear Information System (INIS)
Salvestrini, Stefano; Leone, Vincenzo; Iovino, Pasquale; Canzano, Silvana; Capasso, Sante
2014-01-01
Highlights: • Different methods to derive sorption thermodynamic parameters have been discussed. • ΔG° and, ΔS° values depend on the selected standard states. • Isosteric heat values help in evaluating the applicability of the sorption models. -- Abstract: This is a comparative analysis of popular methods currently in use to derive sorption thermodynamic parameters from temperature dependence of sorption isotherms. It is emphasized that the standard and isosteric thermodynamic parameters have sharply different meanings. Moreover, it is shown with examples how the sorption model adopted conditions the standard state and consequently the value of ΔG° and ΔS°. These trivial but often neglected aspects should carefully be considered when comparing thermodynamic parameters from different literature sources. An effort by the scientific community is needed to define criteria for the choice of the standard state in sorption processes
Abnormal grain growth: a non-equilibrium thermodynamic model for multi-grain binary systems
Czech Academy of Sciences Publication Activity Database
Svoboda, Jiří; Fischer, F. D.
2014-01-01
Roč. 22, č. 1 (2014), Art . No. 015013 ISSN 0965-0393 Institutional support: RVO:68081723 Keywords : grain boundary segregation * abnormal grain growth * theory * modelling * solute drag Subject RIV: BJ - Thermodynamics Impact factor: 2.167, year: 2014
Study of energy fluctuation effect on the statistical mechanics of equilibrium systems
International Nuclear Information System (INIS)
Lysogorskiy, Yu V; Wang, Q A; Tayurskii, D A
2012-01-01
This work is devoted to the modeling of energy fluctuation effect on the behavior of small classical thermodynamic systems. It is known that when an equilibrium system gets smaller and smaller, one of the major quantities that becomes more and more uncertain is its internal energy. These increasing fluctuations can considerably modify the original statistics. The present model considers the effect of such energy fluctuations and is based on an overlapping between the Boltzmann-Gibbs statistics and the statistics of the fluctuation. Within this o verlap statistics , we studied the effects of several types of energy fluctuations on the probability distribution, internal energy and heat capacity. It was shown that the fluctuations can considerably change the temperature dependence of internal energy and heat capacity in the low energy range and at low temperatures. Particularly, it was found that, due to the lower energy limit of the systems, the fluctuations reduce the probability for the low energy states close to the lowest energy and increase the total average energy. This energy increasing is larger for lower temperatures, making negative heat capacity possible for this case.
Khazri, Hassen; Ghorbel-Abid, Ibtissem; Kalfat, Rafik; Trabelsi-Ayadi, Malika
2017-10-01
This study aimed to describe the adsorption of three pharmaceuticals compounds (ibuprofen, naproxen and carbamazepine) onto natural clay on the basis of equilibrium parameters such as a function of time, effect of pH, varying of the concentration and the temperature. Adsorption kinetic data were modeled using the Lagergren's first-order and the pseudo-second-order kinetic equations. The kinetic results of adsorption are described better using the pseudo-second order model. The isotherm results were tested in the Langmuir, Freundlich and Dubinin-Radushkevich models. The thermodynamic parameters obtained indicate that the adsorption of pharmaceuticals on the clay is a spontaneous and endothermic process.
Comments on the compatibility of thermodynamic equilibrium conditions with lattice propagators
Canfora, Fabrizio; Giacomini, Alex; Pais, Pablo; Rosa, Luigi; Zerwekh, Alfonso
2016-08-01
In this paper the compatibility is analyzed of the non-perturbative equations of state of quarks and gluons arising from the lattice with some natural requirements for self-gravitating objects at equilibrium: the existence of an equation of state (namely, the possibility to define the pressure as a function of the energy density), the absence of superluminal propagation and Le Chatelier's principle. It is discussed under which conditions it is possible to extract an equation of state (in the above sense) from the non-perturbative propagators arising from the fits of the latest lattice data. In the quark case, there is a small but non-vanishing range of temperatures in which it is not possible to define a single-valued functional relation between density and pressure. Interestingly enough, a small change of the parameters appearing in the fit of the lattice quark propagator (of around 10 %) could guarantee the fulfillment of all the three conditions (keeping alive, at the same time, the violation of positivity of the spectral representation, which is the expected signal of confinement). As far as gluons are concerned, the analysis shows very similar results. Whether or not the non-perturbative quark and gluon propagators satisfy these conditions can have a strong impact on the estimate of the maximal mass of quark stars.
Comments on the compatibility of thermodynamic equilibrium conditions with lattice propagators
Energy Technology Data Exchange (ETDEWEB)
Canfora, Fabrizio [Centro de Estudios Cientificos (CECs), Valdivia (Chile); Giacomini, Alex [Universidad Austral de Chile, Instituto de Ciencias Fisicas y Matematicas, Valdivia (Chile); Pais, Pablo [Centro de Estudios Cientificos (CECs), Valdivia (Chile); Universite Libre de Bruxelles and International Solvay Institutes, Physique Theorique et Mathematique, Brussels (Belgium); Rosa, Luigi [Universita di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Dipartimento di Fisica, Naples (Italy); Complesso Universitario di Monte S. Angelo, Naples (Italy); INFN, Sezione di Napoli, Naples (Italy); Zerwekh, Alfonso [Universidad Tecnica Federico Santa Maria, Departamento de Fisica and Centro Cientifico-Tecnologico de Valparaiso, Valparaiso (Chile)
2016-08-15
In this paper the compatibility is analyzed of the non-perturbative equations of state of quarks and gluons arising from the lattice with some natural requirements for self-gravitating objects at equilibrium: the existence of an equation of state (namely, the possibility to define the pressure as a function of the energy density), the absence of superluminal propagation and Le Chatelier's principle. It is discussed under which conditions it is possible to extract an equation of state (in the above sense) from the non-perturbative propagators arising from the fits of the latest lattice data. In the quark case, there is a small but non-vanishing range of temperatures in which it is not possible to define a single-valued functional relation between density and pressure. Interestingly enough, a small change of the parameters appearing in the fit of the lattice quark propagator (of around 10 %) could guarantee the fulfillment of all the three conditions (keeping alive, at the same time, the violation of positivity of the spectral representation, which is the expected signal of confinement). As far as gluons are concerned, the analysis shows very similar results. Whether or not the non-perturbative quark and gluon propagators satisfy these conditions can have a strong impact on the estimate of the maximal mass of quark stars. (orig.)
Comments on the compatibility of thermodynamic equilibrium conditions with lattice propagators
International Nuclear Information System (INIS)
Canfora, Fabrizio; Giacomini, Alex; Pais, Pablo; Rosa, Luigi; Zerwekh, Alfonso
2016-01-01
In this paper the compatibility is analyzed of the non-perturbative equations of state of quarks and gluons arising from the lattice with some natural requirements for self-gravitating objects at equilibrium: the existence of an equation of state (namely, the possibility to define the pressure as a function of the energy density), the absence of superluminal propagation and Le Chatelier's principle. It is discussed under which conditions it is possible to extract an equation of state (in the above sense) from the non-perturbative propagators arising from the fits of the latest lattice data. In the quark case, there is a small but non-vanishing range of temperatures in which it is not possible to define a single-valued functional relation between density and pressure. Interestingly enough, a small change of the parameters appearing in the fit of the lattice quark propagator (of around 10 %) could guarantee the fulfillment of all the three conditions (keeping alive, at the same time, the violation of positivity of the spectral representation, which is the expected signal of confinement). As far as gluons are concerned, the analysis shows very similar results. Whether or not the non-perturbative quark and gluon propagators satisfy these conditions can have a strong impact on the estimate of the maximal mass of quark stars. (orig.)
The Use of VMD Data/Model to Test Different Thermodynamic Models for Vapour-Liquid Equilibrium
DEFF Research Database (Denmark)
Abildskov, Jens; Azquierdo-Gil, M.A.; Jonsson, Gunnar Eigil
2004-01-01
Vacuum membrane distillation (VMD) has been studied as a separation process to remove volatile organic compounds from aqueous streams. A vapour pressure difference across a microporous hydrophobic membrane is the driving force for the mass transport through the membrane pores (this transport take...... place in vapour phase). The vapour pressure difference is obtained in VMD processes by applying a vacuum on one side of the membrane. The membrane acts as a mere support for the liquid-vapour equilibrium. The evaporation of the liquid stream takes place on the feed side of the membrane...... values; membrane type: PTFE/PP/PVDF; feed flow rate; feed temperature. A comparison is made between different thermodynamic models for calculating the vapour-liquid equilibrium at the membrane/pore interface. (C) 2004 Elsevier B.V. All rights reserved....
Energy Technology Data Exchange (ETDEWEB)
Pashai Gatabi, Maliheh; Milani Moghaddam, Hossain, E-mail: Milani@umz.ac.ir [University of Mazandaran, Soid State Physics Department (Iran, Islamic Republic of); Ghorbani, Mohsen [Babol Noshirvani University of Technology, Chemical Engineering Department (Iran, Islamic Republic of)
2016-07-15
Adsorptive potential of maghemite decorated multiwalled carbon nanotubes (MWCNTs) for the removal of cadmium ions from aqueous solution was investigated. The magnetic nanoadsorbent was synthesized using a versatile and cost effective chemical route. Structural, magnetic and surface charge properties of the adsorbent were characterized using FTIR, XRD, TEM, VSM analysis and pH{sub PZC} determination. Batch adsorption experiments were performed under varied system parameters such as pH, contact time, initial cadmium concentration and temperature. Highest cadmium adsorption was obtained at pH 8.0 and contact time of 30 min. Adsorption behavior was kinetically studied using pseudo first-order, pseudo second-order, and Weber–Morris intra particle diffusion models among which data were mostly correlated to pseudo second-order model. Adsorbate-adsorbent interactions as a function of temperature was assessed by Langmuir, Freundlich, Dubinin–Radushkevich (D-R) and Temkin isotherm models from which Freundlich model had the highest consistency with the data. The adsorption capacity increased with increasing temperature and maximum Langmuir’s adsorption capacity was found to be 78.81 mg g{sup −1} at 298 K. Thermodynamic parameters and activation energy value suggest that the process of cadmium removal was spontaneous and physical in nature, which lead to fast kinetics and high regeneration capability of the nanoadsorbent. Results of this work are of great significance for environmental applications of magnetic MWCNTs as promising adsorbent for heavy metals removal from aqueous solutions.Graphical Abstract.
SNG from coal: thermodynamic and kinetic constraints; use of nuclear energy
International Nuclear Information System (INIS)
Shapira, D.
1983-01-01
Part I contains an analysis of the thermodynamic constraints of converting coal to SNG. It is shown that the thermodynamic constraints that limit the thermal efficiency are not inherent, but are the result of design decisions, based on available technology, as well as on the kinetic properties of available catalysts. The latter, limits the yield of methane to that obtainable at global equilibrium over carbon in the presence of CO, H 2 , CO 2 and H 2 O. The equilibrium composition is shown to be independent of the thermodynamic properties of the char or coal fed. These limitations give the nonisothermal two-stage processes significant thermodynamic advantages. The analysis in part I results in suggesting directions for modifying present processes in order to obtain higher thermal efficiences. It also presents two-stage process schemes which may have significant advantages over present technology. As the methodology used for the thermodynamic analysis contains some novel elements, it should be of interest to the reaction engineer in general, and should be applicable to a wide range of catalytic and noncatalytic processes. Part II focuses on the use of nuclear energy in the production of synthetic fuel. Two processes for the production of hydrogen (which is used in coal-to-SNG processes) are analyzed and compared. The two processes are: 1) hydrogen from electrolysis of water using nuclear heat. 2) Hydrogen from steam reforming of methane using nuclear heat. The method used is differential economic analysis which focuses on evaluating the inherent advantages and disadvantages of the proposed technologies. Part II shows that the use of high temperature heat in production of hydrogen from coal is less attractive than the use of the same heat to generate electricity and split water into H 2 and O 2
Directory of Open Access Journals (Sweden)
Samson Abramsky
2015-11-01
Full Text Available Maxwell's Demon, 'a being whose faculties are so sharpened that he can follow every molecule in its course', has been the centre of much debate about its abilities to violate the second law of thermodynamics. Landauer's hypothesis, that the Demon must erase its memory and incur a thermodynamic cost, has become the standard response to Maxwell's dilemma, and its implications for the thermodynamics of computation reach into many areas of quantum and classical computing. It remains, however, still a hypothesis. Debate has often centred around simple toy models of a single particle in a box. Despite their simplicity, the ability of these systems to accurately represent thermodynamics (specifically to satisfy the second law and whether or not they display Landauer Erasure, has been a matter of ongoing argument. The recent Norton-Ladyman controversy is one such example. In this paper we introduce a programming language to describe these simple thermodynamic processes, and give a formal operational semantics and program logic as a basis for formal reasoning about thermodynamic systems. We formalise the basic single-particle operations as statements in the language, and then show that the second law must be satisfied by any composition of these basic operations. This is done by finding a computational invariant of the system. We show, furthermore, that this invariant requires an erasure cost to exist within the system, equal to kTln2 for a bit of information: Landauer Erasure becomes a theorem of the formal system. The Norton-Ladyman controversy can therefore be resolved in a rigorous fashion, and moreover the formalism we introduce gives a set of reasoning tools for further analysis of Landauer erasure, which are provably consistent with the second law of thermodynamics.
Trigenerative micro compressed air energy storage: Concept and thermodynamic assessment
International Nuclear Information System (INIS)
Facci, Andrea L.; Sánchez, David; Jannelli, Elio; Ubertini, Stefano
2015-01-01
Highlights: • The trigenerative-CAES concept is introduced. • The thermodynamic feasibility of the trigenerative-CAES is assessed. • The effects of the relevant parameter on the system performances are dissected. • Technological issues on the trigenerative-CAES are highlighted. - Abstract: Energy storage is a cutting edge front for renewable and sustainable energy research. In fact, a massive exploitation of intermittent renewable sources, such as wind and sun, requires the introduction of effective mechanical energy storage systems. In this paper we introduce the concept of a trigenerative energy storage based on a compressed air system. The plant in study is a simplified design of the adiabatic compressed air energy storage and accumulates mechanical and thermal (both hot and cold) energy at the same time. We envisage the possibility to realize a relatively small size trigenerative compressed air energy storage to be placed close to the energy demand, according to the distributed generation paradigm. Here, we describe the plant concept and we identify all the relevant parameters influencing its thermodynamic behavior. Their effects are dissected through an accurate thermodynamic model. The most relevant technological issues, such as the guidelines for a proper choice of the compressor, expander and heat exchangers are also addressed. Our results show that T-CAES may have an interesting potential as a distributed system that combines electricity storage with heat and cooling energy production. We also show that the performances are significantly influenced by some operating and design parameters, whose feasibility in real applications must be considered.
Directory of Open Access Journals (Sweden)
Marius Sebastian Secula
2011-12-01
Full Text Available The present paper approaches the study of the adsorption of an acid dye on a commercial granular activated carbon (GAC. Batch experiments were conducted to study the equilibrium isotherms and kinetics of Indigo Carmine on GAC. The kinetic data were analyzed using the Lagargren, Ho, Elovich, Weber-Morris and Bangham models in order to establish the most adequate model that describes this process, and to investigate the rate of IC adsorption. Equilibrium data were fitted to Langmuir and Freundlich isotherms. Langmuir isotherm equilibrium model and Ho kinetic model fitted best the experimental data.The effects of temperature (25 – 45 °C, initial concentration of dye (7.5 – 150 mg•L−1, GAC dose (0.02 – 1 g•L-1, particle size (2 – 7 mm in diameter, solution pH (3 – 11 on GAC adsorption capacity were established. The adsorption process is found to be favored by a neutral pH, high values of temperature and small particle sizes. The highest adsorption capacity (133.8 mg•g-1 of the GAC is obtained at 45 °C. The removal efficiency increases with GAC dose at relatively low initial concentrations of dye. Thermodynamic parameters such as standard enthalpy (H, standard entropy (S and standard free energy (G were evaluated. The adsorption of Indigo Carmine onto GAC is an endothermic process.
A Thermodynamic Point of View on Dark Energy Models
Directory of Open Access Journals (Sweden)
Vincenzo F. Cardone
2017-07-01
Full Text Available We present a conjugate analysis of two different dark energy models, namely the Barboza–Alcaniz parameterization and the phenomenologically-motivated Hobbit model, investigating both their agreement with observational data and their thermodynamical properties. We successfully fit a wide dataset including the Hubble diagram of Type Ia Supernovae, the Hubble rate expansion parameter as measured from cosmic chronometers, the baryon acoustic oscillations (BAO standard ruler data and the Planck distance priors. This analysis allows us to constrain the model parameters, thus pointing at the region of the wide parameters space, which is worth focusing on. As a novel step, we exploit the strong connection between gravity and thermodynamics to further check models’ viability by investigating their thermodynamical quantities. In particular, we study whether the cosmological scenario fulfills the generalized second law of thermodynamics, and moreover, we contrast the two models, asking whether the evolution of the total entropy is in agreement with the expectation for a closed system. As a general result, we discuss whether thermodynamic constraints can be a valid complementary way to both constrain dark energy models and differentiate among rival scenarios.
Thermodynamical properties of dark energy with the equation of state ω=ω0+ω1z
International Nuclear Information System (INIS)
Zhang Yongping; Yi Zelong; Zhang Tongjie; Liu Wenbiao
2008-01-01
The thermodynamical properties of dark energy are usually investigated with the equation of state ω=ω 0 +ω 1 z. Recent observations show that our Universe is accelerating, and the apparent horizon and the event horizon vary with redshift z. Because definitions of the temperature and entropy of a black hole are used to describe the two horizons of the Universe, we examine the thermodynamical properties of the Universe, which is enveloped by the apparent horizon and the event horizon, respectively. We show that the first and the second laws of thermodynamics inside the apparent horizon in any redshift are satisfied, while they are broken down inside the event horizon in some redshifts. Therefore, the apparent horizon for the Universe may be the boundary of thermodynamical equilibrium for the Universe like the event horizon for a black hole
Thermodynamics for the practicing engineer
Theodore, Louis; Vanvliet, Timothy
2009-01-01
This book concentrates specifically on the applications of thermodynamics, rather than the theory. It addresses both technical and pragmatic problems in the field, and covers such topics as enthalpy effects, equilibrium thermodynamics, non-ideal thermodynamics and energy conversion applications. Providing the reader with a working knowledge of the principles of thermodynamics, as well as experience in their application, it stands alone as an easy-to-follow self-teaching aid to practical applications and contains worked examples.
Pavliuk, A. O.; Zagumennov, V. S.; Kotlyarevskiy, S. G.; Bespala, E. V.
2018-01-01
The problems of accumulation of nuclear fuel spills in the graphite stack in the course of operation of uranium-graphite nuclear reactors are considered. The results of thermodynamic analysis of the processes in the graphite stack at dehydration of a technological channel, fuel element shell unsealing and migration of fission products, and activation of stable nuclides in structural elements of the reactor and actinides inside the graphite moderator are given. The main chemical reactions and compounds that are produced in these modes in the reactor channel during its operation and that may be hazardous after its shutdown and decommissioning are presented. Thermodynamic simulation of the equilibrium composition is performed using the specialized code TERRA. The results of thermodynamic simulation of the equilibrium composition in different cases of technological channel dehydration in the course of the reactor operation show that, if the temperature inside the active core of the nuclear reactor increases to the melting temperature of the fuel element, oxides and carbides of nuclear fuel are produced. The mathematical model of the nonstationary heat transfer in a graphite stack of a uranium-graphite reactor in the case of the technological channel dehydration is presented. The results of calculated temperature evolution at the center of the fuel element, the replaceable graphite element, the air gap, and in the surface layer of the block graphite are given. The numerical results show that, in the case of dehydration of the technological channel in the uranium-graphite reactor with metallic uranium, the main reaction product is uranium dioxide UO2 in the condensed phase. Low probability of production of pyrophoric uranium compounds (UH3) in the graphite stack is proven, which allows one to disassemble the graphite stack without the risk of spontaneous graphite ignition in the course of decommissioning of the uranium-graphite nuclear reactor.
International Nuclear Information System (INIS)
Domanska, Urszula; Lachwa, Joanna
2005-01-01
The (solid + liquid) equilibrium (SLE) of eight binary systems containing N-methyl-2-pyrrolidinone (NMP) with (2-propanone, or 2-butanone, or 2-pentanone, or 3-pentanone, or cyclopentanone, or 2-hexanone, or 4-methyl-2-pentanone, or 3-heptanone) were carried out by using a dynamic method from T = 200 K to the melting point of the NMP. The isothermal (vapour + liquid) equilibrium data (VLE) have been measured for three binary mixtures of NMP with 2-propanone, 3-pentanone and 2-hexanone at pressure range from p = 0 kPa to p = 115 kPa. Data were obtained at the temperature T = 333.15 K for the first system and at T = 373.15 K for the second two systems. The experimental results of SLE have been correlated using the binary parameters Wilson, UNIQUAC ASM and two modified NRTL equations. The root-mean-square deviations of the solubility temperatures for all the calculated values vary from (0.32 K to 0.68 K) and depend on the particular equation used. The data of VLE were correlated with one to three parameters in the Redlich-Kister expansion. Binary mixtures of NMP with (2-propanone, or 2-butanone, or 2-pentanone, or 3-pentanone, or cyclopentanone, or 2-hexanone, or 4-methyl-2-pentanone, or 3-heptanone) have been investigated in the framework of the modified UNIFAC (Do) model. The reported new interaction parameters for NMP-group (c-CONCH 3 ) and carbonyl group ( C=O) let the model consistently described a set of thermodynamic properties, including (solid + liquid) equilibrium (vapour + liquid) equilibrium, excess Gibbs energy and molar excess enthalpies of mixing. Our experimental and literature data of binary mixtures containing NMP and ketones were compared with the results of prediction with the modified UNIFAC (Do) model
International Nuclear Information System (INIS)
Sharma, Rohit; Singh, Kuldip
2014-01-01
In the present work, two cases of thermal plasma have been considered; the ground state plasma in which all the atoms and ions are assumed to be in the ground state and the excited state plasma in which atoms and ions are distributed over various possible excited states. The variation of Zγ, frozen isentropic coefficient and the isentropic coefficient with degree of ionization and non-equilibrium parameter θ(= T e /T h ) has been investigated for the ground and excited state helium and argon plasmas at pressures 1 atm, 10 atm, and 100 atm in the temperature range from 6000 K to 60 000 K. For a given value of non-equilibrium parameter, the relationship of Zγ with degree of ionization does not show any dependence on electronically excited states in helium plasma whereas in case of argon plasma this dependence is not appreciable till degree of ionization approaches 2. The minima of frozen isentropic coefficient shifts toward lower temperature with increase of non-equilibrium parameter for both the helium and argon plasmas. The lowering of non-equilibrium parameter decreases the frozen isentropic coefficient more emphatically in helium plasma at high pressures in comparison to argon plasma. The increase of pressure slightly reduces the ionization range over which isentropic coefficient almost remains constant and it does not affect appreciably the dependence of isentropic coefficient on non-equilibrium parameter
Fermi, Enrico
1956-01-01
Indisputably, this is a modern classic of science. Based on a course of lectures delivered by the author at Columbia University, the text is elementary in treatment and remarkable for its clarity and organization. Although it is assumed that the reader is familiar with the fundamental facts of thermometry and calorimetry, no advanced mathematics beyond calculus is assumed.Partial contents: thermodynamic systems, the first law of thermodynamics (application, adiabatic transformations), the second law of thermodynamics (Carnot cycle, absolute thermodynamic temperature, thermal engines), the entr
Asfaram, A.; Fathi, M. R.; Khodadoust, S.; Naraki, M.
2014-06-01
The removal of dyes from industrial waste is very important from health and hygiene point of view and for environmental protection. In this work, efficiency and performance of garlic peel (GP) adsorbent for the removal of Direct Red 12B (DR12B) from wastewater was investigated. The influence of variables including pH, concentration of the dye and amount of adsorbent, particle size, contact time and temperature on the dye removal has been investigated. It was observed that the pseudo-second-order kinetic model fits better with good correlation coefficient and the equilibrium data fitted well with the Langmuir model. More than 99% removal efficiency was obtained within 25 min at adsorbent dose of 0.2 g per 50 ml for initial dye concentration of 50 mg L-1. Calculation of various thermodynamic parameters such as, Gibb's free energy, entropy and enthalpy of the on-going adsorption process indicate feasibility and endothermic nature of DR12B adsorption.
Sevim, S; Sorrenti, A; Franco, C; Furukawa, S; Pané, S; deMello, A J; Puigmartí-Luis, J
2018-05-01
Self-assembly is a crucial component in the bottom-up fabrication of hierarchical supramolecular structures and advanced functional materials. Control has traditionally relied on the use of encoded building blocks bearing suitable moieties for recognition and interaction, with targeting of the thermodynamic equilibrium state. On the other hand, nature leverages the control of reaction-diffusion processes to create hierarchically organized materials with surprisingly complex biological functions. Indeed, under non-equilibrium conditions (kinetic control), the spatio-temporal command of chemical gradients and reactant mixing during self-assembly (the creation of non-uniform chemical environments for example) can strongly affect the outcome of the self-assembly process. This directly enables a precise control over material properties and functions. In this tutorial review, we show how the unique physical conditions offered by microfluidic technologies can be advantageously used to control the self-assembly of materials and of supramolecular aggregates in solution, making possible the isolation of intermediate states and unprecedented non-equilibrium structures, as well as the emergence of novel functions. Selected examples from the literature will be used to confirm that microfluidic devices are an invaluable toolbox technology for unveiling, understanding and steering self-assembly pathways to desired structures, properties and functions, as well as advanced processing tools for device fabrication and integration.
International Nuclear Information System (INIS)
Solgy, Mostafa; Taghizadeh, Majid; Ghoddocynejad, Davood
2015-01-01
Highlights: • Adsorption of uranium from sulphate solutions by an anion exchange resin. • The effects of pH, contact time and adsorbent dosage were investigated. • The adsorption equilibrium is well described by the Freundlich isotherm model. • The adsorption kinetics can be predicted by the pseudo second-order model. • The adsorption is a physical, spontaneous and endothermic process. - Abstract: In the present study, adsorption of uranium from sulphate solutions was evaluated using Amberlite IRA-402 resin. The variation of adsorption process was investigated in batch sorption mode. The parameters studied were pH, contact time and adsorbent dosage. Langmuir and Freundlich isotherm models were used in order to present a mathematical description of the equilibrium data at three different temperatures (25 °C, 35 °C and 45 °C). The final results confirmed that the equilibrium data tend to follow Freundlich isotherm model. The maximum adsorption capacity of Amberlite IRA-402 for uranium(VI) was evaluated to be 213 mg/g for the Langmuir model at 25 °C. The adsorption of uranium on the mentioned anion exchange resin was found to follow the pseudo-second order kinetic model, indicating that chemical adsorption was the rate limiting-step. The values of thermodynamic parameters proved that adsorption process of uranium onto Amberlite IRA-402 resin could be considered endothermic (ΔH > 0) and spontaneous (ΔG < 0)
Phase rule calculations and the thermodynamics of reactive systems under chemical equilibrium
Directory of Open Access Journals (Sweden)
PLATT G. M.
1999-01-01
Full Text Available In this paper, we examine the resolution of some phase rule problems within the context of multiple chemical equilibrium reactions, using cubic equations of state and an activity coefficient model. Bubble and dew reactive surfaces, reactive azeotropic loci and reactive critical loci are generated and presented in graphical form. Also isobaric bubble and dew reactive enthalpy loci, which may be useful in the modeling of reactive distillation operations, are depicted. All the formalism here employed is developed within the coordinate transformation of Ung and Doherty, which is appropriate for equilibrium reactive or multireactive systems. The major contribution of this work is the determination of critical loci for reactive or multireactive equilibrium systems. Since it is known that for some class of chemical reactions the kinetics and product distribution exhibit high sensitivity to pressure near criticality, the present study may be useful as a predicting tool in these cases if the chemical equilibrium condition is not too far from the real phenomenon.
Leermakers, F.A.M.
1988-01-01
The aim of the present study was to unravel the general equilibrium physical properties of lipid bilayer membranes. We consider four major questions:
1. What determines the morphology of the association colloids (micelles, membranes, vesicles) in general?
2. Do the
Eichhorn, Ralf; Aurell, Erik
2014-04-01
'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response
Hütter, Markus; Brader, Joseph M.
2009-01-01
We examine the origins of nonlocality in a nonisothermal hydrodynamic formulation of a one-component fluid of particles that exhibit long-range correlations, e.g., due to a spherically symmetric, long-range interaction potential. In order to furnish the continuum modeling with physical understanding of the microscopic interactions and dynamics, we make use of systematic coarse graining from the microscopic to the continuum level. We thus arrive at a thermodynamically admissible and closed set...
International Nuclear Information System (INIS)
Naslain, R.; Thebault, J.; Hagenmuller, P.; Bernard, C.
1979-01-01
A thermodynamic approach based on the minimization of the total Gibbs free energy of the system is used to study the chemical vapour deposition (CVD) of boron from BCl 3 -H 2 or BBr 3 -H 2 mixtures on various types of substrates (at 1000 < T< 1900 K and 1 atm). In this approach it is assumed that states close to equilibrium are reached in the boron CVD apparatus. (Auth.)
Equilibrium Transitions from Non Renewable Energy to Renewable Energy under Capacity Constraints
Amigues, Jean-Pierre; Ayong Le Kama, Alain; Moreaux, Michel
2013-01-01
We study the transition between non-renewable and renewable energy sources with adjustment costs over the production capacity of renewable energy. Assuming constant variable marginal costs for both energy sources, convex adjustment costs and a more expensive renewable energy, we show the following. With sufficiently abundant non-renewable energy endowments, the dynamic equilibrium path is composed of a first time phase of only non-renewable energy use followed by a transition phase substituti...
Zhu, Huayang; Ricote, Sandrine; Coors, W Grover; Kee, Robert J
2015-01-01
A model-based interpretation of measured equilibrium conductivity and conductivity relaxation is developed to establish thermodynamic, transport, and kinetics parameters for multiple charged defect conducting (MCDC) ceramic materials. The present study focuses on 10% yttrium-doped barium zirconate (BZY10). In principle, using the Nernst-Einstein relationship, equilibrium conductivity measurements are sufficient to establish thermodynamic and transport properties. However, in practice it is difficult to establish unique sets of properties using equilibrium conductivity alone. Combining equilibrium and conductivity-relaxation measurements serves to significantly improve the quantitative fidelity of the derived material properties. The models are developed using a Nernst-Planck-Poisson (NPP) formulation, which enables the quantitative representation of conductivity relaxations caused by very large changes in oxygen partial pressure.
Li, Ming-zhou; Zhou, Jie-min; Tong, Chang-ren; Zhang, Wen-hai; Chen, Zhuo; Wang, Jin-liang
2018-05-01
Based on the principle of multiphase equilibrium, a mathematical model of the copper flash converting process was established by the equilibrium constant method, and a computational system was developed with the use of MetCal software platform. The mathematical model was validated by comparing simulated outputs, industrial data, and published data. To obtain high-quality blister copper, a low copper content in slag, and increased impurity removal rate, the model was then applied to investigate the effects of the operational parameters [oxygen/feed ratio (R OF), flux rate (R F), and converting temperature (T)] on the product weights, compositions, and the distribution behaviors of impurity elements. The optimized results showed that R OF, R F, and T should be controlled at approximately 156 Nm3/t, within 3.0 pct, and at approximately 1523 K (1250 °C), respectively.
International Nuclear Information System (INIS)
Li, Guanchen; Spakovsky, Michael R. von
2016-01-01
Conventional first principle approaches for studying nonequilibrium or far-from-equilibrium processes depend on the mechanics of individual particles or quantum states. They also require many details of the mechanical features of a system to arrive at a macroscopic property. In contrast, thermodynamics provides an approach for determining macroscopic property values without going into these details, because the overall effect of particle dynamics results, for example, at stable equilibrium in an invariant pattern of the “Maxwellian distribution”, which in turn leads to macroscopic properties. However, such an approach is not generally applicable to a nonequilibrium process except in the near-equilibrium realm. To adequately address these drawbacks, steepest-entropy-ascent quantum thermodynamics (SEAQT) provides a first principle, thermodynamic-ensemble approach applicable to the entire nonequilibrium realm. Based on prior developments by the authors, this paper applies the SEAQT framework to modeling the nonquasi-equilibrium cycle, which a system with variable volume undergoes. Using the concept of hypoequilibrium state and nonequilibrium intensive properties, this framework provides a complete description of the nonequilibrium evolution in state of the system. Results presented here reveal how nonequilibrium effects influence the performance of the cycle. - Highlights: • First-principles nonequilibrium model of thermodynamic cycles. • Study of thermal efficiency losses due to nonequilibrium effects. • Study of systems undergoing nonquasi-equilibrium processes. • Study of the coupling of system relaxation and interaction with a reservoir.
Equilibrium and Thermodynamic Studies of Methane Adsorption on Multi-Walled Carbon Nanotube
Sanaz. Monemtabary; Mojtaba Shariati Niasar; Mohsen Jahanshahi; Ali Asghar Ghoreyshi
2013-01-01
In this work, The adsorption of methane onto multi-walled carbon nanotubes (MWCNTs) was studied, in which the influences of temperatureand pressure were investigated. The physical properties of the MWCNT were systematically characterised by Scanning Electron Microscopy (SEM) and Brunauere-Emmette-Teller (BET) surface area measurements. The equilibrium adsorption data were analyzed using threecommon adsorption models: Langmuir, Freundlich and Sips. All of the models fit the experimental result...
Adsorption of Benzaldehyde on Granular Activated Carbon: Kinetics, Equilibrium, and Thermodynamic
Rajoriya, R.K.; Prasad, B.; Mishra, I.M.; Wasewar, K.L.
2007-01-01
Adsorption isotherms of benzaldehyde from aqueous solutions onto granular activated carbon have been determined and studied the effect of dosage of granular activated carbon, contact time, and temperature on adsorption. Optimum conditions for benzaldehyde removal were found adsorbent dose 4 g l–1 of solution and equilibrium time t 4 h. Percent removal of benzaldehyde increases with the increase in adsorbent dose for activated carbon, however, it decreases with increase in benzaldehyde m...
Pal, Susmita; Nandi, Arun K
2005-02-24
The equilibrium cocrystal formation of poly(3-alkyl thiophene) (P3AT) blends has been studied by isothermal cocrystallization in a differential scanning calorimeter (DSC-7). The equilibrium melting points (T(m)0) of the cocrystals are measured using the Hoffman-Weeks extrapolation procedure. The equilibrium phase diagrams are of three different types: (a) concave upward, (b) linear, and (c) linear with phase separation at higher content of lower melting component. The phase diagram nature depends on the regioregularity difference and also on the difference in the number of carbon atoms in the pendent alkyl group of the components. The origin of biphasic nature of type "c" phase diagram has been explored from the glass transition temperature (Tg) measurement using a dynamic mechanical analyzer. The biphasic compositions show two glass transition temperatures (Tg) as well as two beta transition temperatures (T beta). The T(g)s of phase-separated regions correspond to almost the component values but the T(beta)s correspond to that of a lower (T beta) component value, and the other is higher than that of the higher (T beta) component value. Possible reasons are discussed from the interchain lamella thickness in the P3AT blends and molecular modeling using molecular mechanics program.
International Nuclear Information System (INIS)
Boyarchuk, A.A.; Lyubimkov, L.S.; Sakhibullin, N.A.
1985-01-01
For a number of class F supergiants and dwarfs, non-LTE calculations have been made of the Fe I-Fe II ionization balance. It is shown that deviations from local thermodynamic equilibrium lead to a strong overionization of the Fe I atoms in the upper layers of the atmosphere. This confirms the conclusion obtained by Lyubimkov and Boyarchuk on the basis of an investigation of microturbulence in F supergiants. The reason for the overionization (compared with LTE) is the nonequality of the recombination and photoionization temperatures: To recombination processes there corresponds a local temperature T(/tau/), whereas the photoionization takes place under the influence of ultraviolet radiation from deeper and hotter layers of the atmosphere. The equivalent widths of some Fe I lines have been calculated. It is shown that neglect of the overionization in the analysis of sufficiently strong lines may lead to an underestimation of the iron abundance by an order of magnitude
International Nuclear Information System (INIS)
Ajemba, R.O.
2015-01-01
The adsorption performance of modified Nkalagu bentonite in removing Congo red (CR) from solution was investigated. The raw bentonite was modified by three different physicochemical methods: thermal activation (TA), acid activation (AA), and combined acid and thermal activation (ATA). The Congo red adsorption increased with increase in contact time, initial dye concentration, adsorbent dosage, temperature, and pH change. The results of the kinetics analysis of the adsorption data revealed that adsorption follows pseudo second-order kinetics. Analysis of the equilibrium data showed that Langmuir isotherm provided a better fit to the data. Evaluation of the thermodynamic parameters revealed that adsorption process is spontaneous and endothermic. The results from this study suggest that a combination of thermal and acid activation is an effective modification method to improve adsorption capacity of bentonite and makes the bentonite as low-cost adsorbent for removal of water pollutants. (author)
International Nuclear Information System (INIS)
Puigdomenech, I.; Bruno, J.
1995-04-01
Thermodynamic data has been selected for solids and aqueous species of technetium. Equilibrium constants have been calculated in the temperature range 0 to 300 deg C at a pressure of 1 bar for T r Cdeg pm values for mononuclear hydrolysis reactions. The formation constants for chloro complexes of Tc(V) and Tc(IV), whose existence is well established, have been estimated. The majority of entropy and heat capacity values in the data base have also been estimated, and therefore temperature extrapolations are largely based on estimations. The uncertainties derived from these calculations are described. Using the data base developed in this work, technetium solubilities have been calculated as a function of temperature for different chemical conditions. The implications for the mobility of Tc under nuclear repository conditions are discussed. 70 refs
Directory of Open Access Journals (Sweden)
E. Igberase
2017-01-01
Full Text Available In this investigation, an amino functionalized adsorbent was developed by grafting 4-aminobenzoic acid onto the backbone of cross-linked chitosan beads. The 3 sets of beads including chitosan (CX, glutaraldehyde cross-linked chitosan (CCX, and 4-aminobenzoic acid grafted cross-linked chitosan (FGCX were characterized by FTIR, XRD, SEM, and TGA. The water content and amine concentration of FGCX were determined. The effect of adsorption parameters was studied and the optimum was used for further studies. Equilibrium data was obtained from the adsorption experiment carried out at different initial concentration; the data were applied in isotherm, thermodynamics, and kinetic studies. The Langmuir and Dubinin-Kaganer-Radushkevich (DKR models were successful in describing the isotherm data for the considered metal ions while the Freundlich and Temkin model fit some of the considered metal ions. Pseudo-second-order and intraparticle model described the kinetic data quite well. Thermodynamic parameters such as Gibb’s free energy change (ΔGo, enthalpy change (ΔHo, and entropy change (ΔSo were calculated and the results showed that the adsorption of Pb, Cu, Ni, Zn, and Cd ions onto FGCX is spontaneous and endothermic in nature. Regeneration of the spent adsorbent was efficient for the considered metal ions.
Thermodynamic modeling of the stacking fault energy of austenitic steels
International Nuclear Information System (INIS)
Curtze, S.; Kuokkala, V.-T.; Oikari, A.; Talonen, J.; Haenninen, H.
2011-01-01
The stacking fault energies (SFE) of 10 austenitic steels were determined in the temperature range 50 ≤ T ≤ 600 K by thermodynamic modeling of the Fe-Cr-Ni-Mn-Al-Si-Cu-C-N system using a modified Olson and Cohen modeling approach (Olson GB, Cohen M. Metall Trans 1976;7A:1897 ). The applied model accounts for each element's contribution to the Gibbs energy, the first-order excess free energies, magnetic contributions and the effect of interstitial nitrogen. Experimental SFE values from X-ray diffraction measurements were used for comparison. The effect of SFE on deformation mechanisms was also studied by electron backscatter diffraction.
High energy lithium-oxygen batteries - Transport barriers and thermodynamics
Das, Shyamal K.
2012-01-01
We show that it is possible to achieve higher energy density lithium-oxygen batteries by simultaneously lowering the discharge overpotential and increasing the discharge capacity via thermodynamic variables alone. By assessing the relative effects of temperature and pressure on the cell discharge profiles, we characterize and diagnose the critical roles played by multiple dynamic processes that have hindered implementation of the lithium-oxygen battery. © 2012 The Royal Society of Chemistry.
Dreyer, Wolfgang; Guhlke, Clemens; Müller, Rüdiger
2016-09-28
Electron transfer reactions are commonly described by the phenomenological Butler-Volmer equation which has its origin in kinetic theories. The Butler-Volmer equation relates interfacial reaction rates to bulk quantities like the electrostatic potential and electrolyte concentrations. Although the general structure of the equation is well accepted, for modern electrochemical systems like batteries and fuel cells there is still intensive discussion about the specific dependencies of the coefficients. A general guideline for the derivation of Butler-Volmer type equations is missing in the literature. We derive very general relations of Butler-Volmer structure which are based on a rigorous non-equilibrium thermodynamic model and allow for adaption to a wide variety of electrochemical systems. We discuss the application of the new thermodynamic approach to different scenarios like the classical electron transfer reactions at metal electrodes and the intercalation process in lithium-iron-phosphate electrodes. Furthermore we show that under appropriate conditions also adsorption processes can lead to Butler-Volmer equations. We illustrate the application of our theory by a strongly simplified example of electroplating.
International Nuclear Information System (INIS)
Gomez Palacio, German Rau
1998-01-01
Ecology is no more a descriptive and self-sufficient science. Many viewpoints are needed simultaneously to give a full coverage of such complex systems: ecosystems. These viewpoints come from physics, chemistry, and nuclear physics, without a new far from equilibrium thermodynamics and without new mathematical tools such as catastrophe theory, fractal theory, cybernetics and network theory, the development of ecosystem science would never have reached the point of today. Some ideas are presented about the importance that concept such as energy, entropy, exergy information and none equilibrium have in the analysis of processes taking place in ecosystems
International Nuclear Information System (INIS)
Alberty, R.A.; Oppenheim, I.
1993-01-01
When temperature, pressure, and the partial pressure of a reactant are fixed, the criterion of chemical equilibrium can be expressed in terms of the transformed Gibbs energy G' that is obtained by using a Legendre transform involving the chemical potential of the reactant that is fixed. For reactions of ideal gases, the most natural variables to use in the fundamental equation are T, P', and P B , where P' is the partial pressure of the reactants other than the one that is fixed and P B is the partial pressure of the reactant that is fixed. The fundamental equation for G' yields the expression for the transformed entropy S', and a transformed enthalpy can be defined by the additional Legendre transform H'=G'+TS'. This leads to an additional form of the fundamental equation. The calculation of transformed thermodynamic properties and equilibrium compositions is discussed for a simple system and for a general multireaction system. The change, in a reaction, of the binding of the reactant that is at a specified pressure can be calculated using one of the six Maxwell equations of the fundamental equation in G'
Acid-base equilibrium. A thermodynamic study of formation and stability of the Bi-2223 phase
International Nuclear Information System (INIS)
Xi, Z.; Zhou, L.
1993-01-01
A general acid-base equilibrium theory was proposed to explain the formation and stability of the Bi-2223 phase based on the Lewis acid base theory and principle of metallurgical physical chemistry. The acid-base nature of oxide was defined according to the electrostatic force between cation and oxygen anion. A series of experimental facts were systematically explained based on the theory: substitution of Bi for Ca in the Pb-free 2223 phase, and the effect of substitution of the high-valent cation for Bi 3+ ; oxygen-pressure atmosphere, and the heat-schocking technique on the formation and stability of the 2223 phase. 14 refs., 2 tabs
Energy in the environment and the second law of thermodynamics
Mueller, R. F.
1972-01-01
The relationship between the consumption of energy by technological cultures and the second law of thermodynamics is discussed. The analysis is based on a description of the operation of a mechanical device which consumes energy. It is concluded that the flow of energy in manifold spontaneous conditions, which play a vital role in the operation of any technological process, remove most of the energy flow path from the control of the operator. It is stated that the increased efficiency of a process can benefit the environment only as much as this efficiency enables the total energy input to be reduced for a given level of production and increasing efficiency cannot meet the problems of an increased rate of energy utilization.
International Nuclear Information System (INIS)
Wu, Gang; Hu, Yonghong; Gu, Pengfei; Yang, Wenge; Wang, Chunxiao; Ding, Zhiwen; Deng, Renlun; Li, Tao; Hong, Housheng
2016-01-01
Highlights: • The solubility increased with increasing temperature. • The data were fitted using the modified Apelblat equation in pure solvents. • The data were fitted using the CNIBS/R-K model in binary solvent mixture. - Abstract: Knowledge of thermodynamic parameters on corresponding solid-liquid equilibrium of nifedipine in different solvents is essential for a preliminary study of pharmaceutical engineering and industrial applications. In this paper, a gravimetric method was used to correct the solid-liquid equilibrium of nifedipine in methanol, ethanol, 1-butanol, acetone, acetonitrile, ethyl acetate and tetrahydrofuran pure solvents as well as in the (tetrahydrofuran + acetonitrile) mixture solvents at temperatures from 278.15 K to 328.15 K under 0.1 MPa. For the temperature range investigation, the solubility of nifedipine in the solvents increased with increasing temperature. The solubility of nifedipine in tetrahydrofuran is superior to other selected pure solvents. The modified Apelblat model, the Buchowski-Ksiazaczak λh model, and the ideal model were adopted to describe and predict the change tendency of solubility. Computational results showed that the modified Apelblat model stood out to be more suitable with the higher accuracy. The solubility values were fitted using a modified Apelblat model, a variant of the combined nearly ideal binary solvent/Redich-Kister (CNIBS/R-K) model and Jouyban-Acree model in (tetrahydrofuran + acetonitrile) binary solvent mixture. Computational results showed that the CNIBS/R-K model had more advantages than other models.
International Nuclear Information System (INIS)
Duthil, P
2014-01-01
The goal of this paper is to present a general thermodynamic basis that is useable in the context of superconductivity and particle accelerators. The first part recalls the purpose of thermodynamics and summarizes its important concepts. Some applications, from cryogenics to magnetic systems, are covered. In the context of basic thermodynamics, only thermodynamic equilibrium is considered
Energy Technology Data Exchange (ETDEWEB)
Duthil, P [Orsay, IPN (France)
2014-07-01
The goal of this paper is to present a general thermodynamic basis that is useable in the context of superconductivity and particle accelerators. The first part recalls the purpose of thermodynamics and summarizes its important concepts. Some applications, from cryogenics to magnetic systems, are covered. In the context of basic thermodynamics, only thermodynamic equilibrium is considered.
Huff, Vearl N; Gordon, Sanford; Morrell, Virginia E
1951-01-01
A rapidly convergent successive approximation process is described that simultaneously determines both composition and temperature resulting from a chemical reaction. This method is suitable for use with any set of reactants over the complete range of mixture ratios as long as the products of reaction are ideal gases. An approximate treatment of limited amounts of liquids and solids is also included. This method is particularly suited to problems having a large number of products of reaction and to problems that require determination of such properties as specific heat or velocity of sound of a dissociating mixture. The method presented is applicable to a wide variety of problems that include (1) combustion at constant pressure or volume; and (2) isentropic expansion to an assigned pressure, temperature, or Mach number. Tables of thermodynamic functions needed with this method are included for 42 substances for convenience in numerical computations.
Energy Technology Data Exchange (ETDEWEB)
Abdolali, Atefeh [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007 (Australia); Ngo, Huu Hao, E-mail: h.ngo@uts.edu.au [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007 (Australia); Guo, Wenshan [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007 (Australia); Lu, Shaoyong [Chinese Research Academy of Environmental Science, Beijing 100012 (China); Chen, Shiao-Shing; Nguyen, Nguyen Cong [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd, Taipei 106, Taiwan (China); Zhang, Xinbo [Department of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384 (China); Wang, Jie; Wu, Yun [School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)
2016-01-15
A breakthrough biosorbent namely multi-metal binding biosorbent (MMBB) made from a combination of tea wastes, maple leaves and mandarin peels, was prepared to evaluate their biosorptive potential for removal of Cd(II), Cu(II), Pb(II) and Zn(II) from multi-metal aqueous solutions. FTIR and SEM were conducted, before and after biosorption, to explore the intensity and position of the available functional groups and changes in adsorbent surface morphology. Carboxylic, hydroxyl and amine groups were found to be the principal functional groups for the sorption of metals. MMBB exhibited best performance at pH 5.5 with maximum sorption capacities of 31.73, 41.06, 76.25 and 26.63 mg/g for Cd(II), Cu(II), Pb(II) and Zn(II), respectively. Pseudo-first and pseudo-second-order models represented the kinetic experimental data in different initial metal concentrations very well. Among two-parameter adsorption isotherm models, the Langmuir equation gave a better fit of the equilibrium data. For Cu(II) and Zn(II), the Khan isotherm describes better biosorption conditions while for Cd(II) and Pb(II), the Sips model was found to provide the best correlation of the biosorption equilibrium data. The calculated thermodynamic parameters indicated feasible, spontaneous and exothermic biosorption process. Overall, this novel MMBB can effectively be utilized as an adsorbent to remove heavy metal ions from aqueous solutions. - Highlights: • A novel multi-metal binding biosorbent (MMBB) was studied. • The biosorption of Cd{sup 2+}, Cu{sup 2+}, Pb{sup 2+} and Zn{sup 2+} on MMBB was evaluated. • Hydroxyl, carbonyl and amine groups are involved in metal binding of MMBB. • Equilibrium data were presented and the best fitting models were identified. • The obtained results recommend this MMBB as potentially low-cost biosorbent.
Negative energy radiation and the second law of thermodynamics
International Nuclear Information System (INIS)
Deutsch, D.; Ottewill, A.C.; Sciama, D.W.
1982-01-01
It has been suggested that the second law of thermodynamics can be violated by processes involving the absorption by a hot body of negative energy fluxes of quantum origin. We show that this suggestion is false in the case of the process recently proposed by Davies, at least for a simple model of the hot body involved. Such a model body would not in fact be able to absorb the negative energy flux incident on it. We suggest that our argument can be generalized, and that there is no reason to doubt the second law. (orig.)
DEFF Research Database (Denmark)
Bergemann, Maria; Collet, Remo; Schönrich, Ralph
2016-01-01
We have analysed high-resolution spectra of 328 stars and derived Mg abundances using non-local thermodynamic equilibrium (NLTE) spectral line formation calculations and plane-parallel model stellar atmospheres derived from the mean stratification of 3D hydrodynamical surface convection simulations...
Far-from-equilibrium heavy quark energy loss at strong coupling
Chesler, Paul; Rajagopal, Krishna
2013-01-01
We study the energy loss of a heavy quark propagating through the matter produced in the collision of two sheets of energy [1]. Even though this matter is initially far-from-equilibrium we find that, when written in terms of the energy density, the equilibrium expression for heavy quark energy loss describes most qualitative features of our results well. At later times, once a plasma described by viscous hydrodynamics has formed, the equilibrium expression describes the heavy quark energy loss quantitatively. In addition to the drag force that makes it lose energy, a quark moving through the out-of-equilibrium matter feels a force perpendicular to its velocity.
Kusaba, Akira; Li, Guanchen; von Spakovsky, Michael R; Kangawa, Yoshihiro; Kakimoto, Koichi
2017-08-15
Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3Ga-H and N ad -H + Ga-H on a 2 × 2 unit cell) is investigated using steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic-ensemble based, first-principles framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium where the state evolution is a combination of reversible and irreversible dynamics. SEAQT is an ideal choice to handle this problem on a first-principles basis since the chemical adsorption process starts from a highly non-equilibrium state. A result of the analysis shows that the probability of adsorption on 3Ga-H is significantly higher than that on N ad -H + Ga-H. Additionally, the growth temperature dependence of these adsorption probabilities and the temperature increase due to the heat of reaction is determined. The non-equilibrium thermodynamic modeling applied can lead to better control of the MOVPE process through the selection of preferable reconstructed surfaces. The modeling also demonstrates the efficacy of DFT-SEAQT coupling for determining detailed non-equilibrium process characteristics with a much smaller computational burden than would be entailed with mechanics-based, microscopic-mesoscopic approaches.
Abnormal grain growth: a non-equilibrium thermodynamic model for multi-grain binary systems
International Nuclear Information System (INIS)
Svoboda, J; Fischer, F D
2014-01-01
Abnormal grain growth as the abrupt growth of a group of the largest grains in a multi-grain system is treated within the context of unequal retardation of grain growth due to the segregation of solute atoms from the bulk of the grains into the grain boundaries. During grain boundary migration, the segregated solute atoms are dragged under a small driving force or left behind the migrating grain boundary under a large driving force. Thus, the solute atoms in the grain boundaries of large grains, exhibiting a large driving force, can be released from the grain boundary. The mobility of these grain boundaries becomes significantly higher and abnormal grain growth is spontaneously provoked. The mean-field model presented here assumes that each grain is described by its grain radius and by its individual segregation parameter. The thermodynamic extremal principle is engaged to obtain explicit evolution equations for the radius and segregation parameter of each grain. Simulations of grain growth kinetics for various conditions of segregation with the same initial setting (100 000 grains with a given radius distribution) are presented. Depending on the diffusion coefficients of the solute in the grain boundaries, abnormal grain growth may be strongly or marginally pronounced. Solute segregation and drag can also significantly contribute to the stabilization of the grain structure. Qualitative agreement with several experimental results is reported. (paper)
Directory of Open Access Journals (Sweden)
Zonghua Wang
2013-05-01
Full Text Available Doxorubicin hydrochloride (DOX is an effective anticancer agent for leukemia chemotherapy, although its clinical use has been limited because of its side effects such as cardiotoxicity, alopecia, vomiting, and leucopenia. Attention has been focussed on developing new drug carriers with high adsorption capacity and rapid adsorption rate in order to minimize the side effects of DOX. Graphene oxide (GO, a new type of nanomaterial in the carbon family, was prepared by Hummers method and used as adsorbent for DOX from aqueous solution. The physico-chemical properties of GO were characterized by transmission electron microscope (TEM, Fourier transform infrared spectroscopy (FTIR, zeta potential, and element analysis. The adsorption properties of DOX on GO were studied as a function of contact time, adsorbent dosage, temperature and pH value. The results showed that GO had a maximum adsorption capacity of 1428.57 mg/g and the adsorption isotherm data fitted the Langmuir model. The kinetics of adsorption fits a pseudo-second-order model. The thermodynamic studies indicate that the adsorption of DOX on GO is spontaneous and endothermic in nature.
Thermodynamic equilibrium of hydroxyacetic acid in pure and binary solvent systems
International Nuclear Information System (INIS)
Huang, Qiaoyin; Xie, Chuang; Li, Yang; Su, Nannan; Lou, Yajing; Hu, Xiaoxue; Wang, Yongli; Bao, Ying; Hou, Baohong
2017-01-01
Highlights: • Solubility of hydroxyacetic acid in mono-solvents and binary solvent mixtures was measured. • Modified Apelblat, NRTL and Wilson model were used to correlate the solubility data in pure solvents. • CNIBS/R-K and Jouyban-Acree model were used to correlate the solubility in binary solvent mixtures. • The mixing properties were calculated based on the NRTL model. - Abstract: The solubility of hydroxyacetic acid in five pure organic solvents and two binary solvent mixtures were experimentally measured from 273.15 K to 313.15 K at atmospheric pressure (p = 0.1 MPa) by using a dynamic method. The order of solubility in pure organic solvents is ethanol > isopropanol > n-butanol > acetonitrile > ethyl acetate within the investigated temperature range, except for temperature lower than 278 K where the solubility of HA in ethyl acetate is slightly larger than that in acetonitrile. Furthermore, the solubility data in pure solvents were correlated with the modified Apelblat model, NRTL model, and Wilson model and that in the binary solvents mixtures were fitted to the CNIBS/R-K model and Jouyban-Acree model. Finally, the mixing thermodynamic properties of hydroxyacetic acid in pure and binary solvent systems were calculated and discussed.
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Piar Chand
2013-01-01
Full Text Available The adsorption-influencing factors such as pH, dose, and time were optimized by batch adsorption study. A 0.8 g dose, 4.0 pH, and 80 min of contact time were optimized for maximum adsorption of Pb on AP. The adsorption isotherms (Langmuir and Freundlich were well fitted to the data obtained with values of qmax (16.39 mg/g; r2=0.985 and K (16.14 mg/g; r2=0.998, respectively. The kinetics study showed that lead adsorption follows the pseudo-second-order kinetics with correlation coefficient (r2 of 0.999 for all of the concentration range. FTIR spectra also showed that the major functional groups like polyphenols (–OH and carbonyl (–CO were responsible for Pb binding on AP. The thermodynamic parameters as ΔG, ΔH (33.54 J/mol, and ΔS (1.08 J/mol/K were also studied and indicate that the reaction is feasible, endothermic, and spontaneous in nature.
Adsorption of rhodamine B by acid activated carbon-Kinetic, thermodynamic and equilibrium studies
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Shanmugam Arivoli
2009-08-01
Full Text Available A carbonaceous adsorbent prepared from an indigenous waste by acid treatment was tested for its efficiency in removing Rhodamine B (RDB. The parameters studied include agitation time, initial dye concentration, carbon dose, pH and temperature. The adsorption followed first order kinetics and the rate is mainly controlled by intra-particle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm obtained from the Langmuir isotherm plots were 40.161, 35.700, 38.462 and 37.979 mg/g respectively at an initial pH of 7.0 at 30, 40, 50 and 60 0C. The temperature variation study showed that the RDB adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the RDB solutions. Almost 85% removal of RDB was observed at 60 0C. The Langmuir and Freundlich isotherms obtained, positive ?H0 value, pH dependent results and desorption of dye in mineral acid suggest that the adsorption of RDB by Banana bark carbon involves physisorption mechanism.
Directory of Open Access Journals (Sweden)
Ruberlan Gomes da Silva
2017-01-01
Full Text Available Chemical fertilizers, such as potassium chloride, ammonium nitrate and other chemical products like sodium hydroxide and soda ash are produced from electrolyte solutions or brines with a high content of soluble salts. Some of these products are manufactured by fractional crystallization, when several salts are separated as solid phases with high purity (>90%. Due to the large global demand for potassium fertilizers, a good knowledge about the compositions of salts and brines is helpful to design an effective process. A thermodynamic model based on Pitzer and Harvie's model was used to predict the composition of crystallized salts after water removal by forced evaporation and cooling from multicomponent solutions or brines. Initially, the salts’ solubilities in binary systems (NaCl–H2O, KCl–H2O and MgCl2–H2O and ternary system (KCl–MgCl2–H2O were calculated at 20 °C and compared with literature data. Next, the model was compared to our experimental data on the quinary system NaCl–KCl–MgCl2–CaCl2–H2O system at 20 °C. The Pitzer and Harvie's model represented well both the binary and ternary systems. Besides, for the quinary system the fit was good for brine densities up to 1350 kg/m3. The models were used to estimate the chemical composition of the solutions and salts produced by fractional crystallization and in association with material balance to respond to issues related to the production rates in a solar pond containing several salts dissolved, for instance, NaCl, KCl, MgCl2 and CaCl2.
Minimizing the Free Energy: A Computer Method for Teaching Chemical Equilibrium Concepts.
Heald, Emerson F.
1978-01-01
Presents a computer method for teaching chemical equilibrium concepts using material balance conditions and the minimization of the free energy. Method for the calculation of chemical equilibrium, the computer program used to solve equilibrium problems and applications of the method are also included. (HM)
Chun, Paul W.
2003-01-01
Applying the Planck-Benzinger methodology, the sequence-specific hydrophobic interactions of 35 dipeptide pairs were examined over a temperature range of 273–333 K, based on data reported by Nemethy and Scheraga in 1962. The hydrophobic interaction in these sequence-specific dipeptide pairs is highly similar in its thermodynamic behavior to that of other biological systems. The results imply that the negative Gibbs free energy change minimum at a well-defined stable temperature, 〈Ts〉, where t...
Thermodynamic limits of energy harvesting from outgoing thermal radiation.
Buddhiraju, Siddharth; Santhanam, Parthiban; Fan, Shanhui
2018-04-17
We derive the thermodynamic limits of harvesting power from the outgoing thermal radiation from the ambient to the cold outer space. The derivations are based on a duality relation between thermal engines that harvest solar radiation and those that harvest outgoing thermal radiation. In particular, we derive the ultimate limit for harvesting outgoing thermal radiation, which is analogous to the Landsberg limit for solar energy harvesting, and show that the ultimate limit far exceeds what was previously thought to be possible. As an extension of our work, we also derive the ultimate limit of efficiency of thermophotovoltaic systems.
International Nuclear Information System (INIS)
Travaille, G.; Peyrusse, O.; Bousquet, B.; Canioni, L.; Pierres, K. Michel-Le; Roy, S.
2009-01-01
We present a collisional-radiative approach of the theoretical analysis of laser-induced breakdown spectroscopy (LIBS) plasmas. This model, which relies on an optimized effective potential atomic structure code, was used to simulate a pure aluminum plasma. The description of aluminum involved a set of 220 atomic levels representative of three different stages of ionization (Al 0 , Al + and Al ++ ). The calculations were carried for stationary plasmas, with input parameters (n e and T e ) ranging respectively between 10 13-18 cm -3 and 0.3-2 eV. A comparison of our atomic data with some existing databases is made. The code was mainly developed to address the validity of the local thermodynamic equilibrium (LTE) assumption. For usual LIBS plasma parameters, we did not reveal a sizeable discrepancy of the radiative equilibrium of the plasma towards LTE. For cases where LTE was firmly believed to stand, the Boltzmann plot outputs of this code were used to check the physical accuracy of the Boltzmann temperature, as it is currently exploited in several calibration-free laser-induced breakdown spectroscopy (CF-LIBS) studies. In this paper, a deviation ranging between 10 and 30% of the measured Boltzmann temperature to the real excitation temperature is reported. This may be due to the huge dispersion induced on the line emissivities, on which the Boltzmann plots are based to extract this parameter. Consequences of this fact on the CF-LIBS procedure are discussed and further insights to be considered for the future are introduced.
Thermodynamics of energy extraction from fractured hot dry rock
Energy Technology Data Exchange (ETDEWEB)
Lim, J S; Bejan, A [Duke Univ., Durham, NC (United States). Dept. of Mechanical Engineering and Materials Science; Kim, J H [Electric Power Research Inst., Palo Alto, CA (United States)
1992-03-01
It has been proposed to extract energy from the subterranean hot dry rock bed (HDR) by creating one or more narrow fractures in the rock and circulating cold water through the fractures. In time, the temperature of the rock region surrounding the crack drops under the influence of time-dependent conduction. This study presents the most basic thermodynamic aspects (first law and second law) of the HDR energy extraction process. It shows which parameters most influence the amount of useful energy (exergy) extracted from the HDR reservoir over a fixed time interval. For example, the water flow rate can be selected optimally in order to maximize the delivery of exergy over the lifetime of the HDR system. (author).
Sattar, Simeen
2011-01-01
Tris(1,10-phenanthroline)iron(II) is the basis of a suite of four experiments spanning 5 weeks. Students determine the rate law, activation energy, and equilibrium constant for the dissociation of the complex ion in acid solution and base dissociation constant for phenanthroline. The focus on one chemical system simplifies a daunting set of…
International Nuclear Information System (INIS)
Lim, Gyeong Hui
2008-03-01
This book consists of 15 chapters, which are basic conception and meaning of statistical thermodynamics, Maxwell-Boltzmann's statistics, ensemble, thermodynamics function and fluctuation, statistical dynamics with independent particle system, ideal molecular system, chemical equilibrium and chemical reaction rate in ideal gas mixture, classical statistical thermodynamics, ideal lattice model, lattice statistics and nonideal lattice model, imperfect gas theory on liquid, theory on solution, statistical thermodynamics of interface, statistical thermodynamics of a high molecule system and quantum statistics
International Nuclear Information System (INIS)
Omran, Ahmed A.
2013-01-01
Graphical abstract: Bar diagram representing thermodynamic parameters obtained for the partitioning of NSAIDs into human erythrocyte ghost membranes at physiological pH; 7.4. Highlights: • Partition coefficients of NSAIDs into HEG membranes were determined. • Thermodynamic parameters were evaluated and successfully analyzed. • Partitioning of NSAIDs into HEG membranes was exothermic. • Partitioning of NSAIDs into HEG is spontaneous with negative free energy values. • Identical partitioning enthalpy–entropy driven compensation mechanism was shown. -- Abstract: In this work,second derivative spectrophotometry was applied for determining the partition coefficients (K p s) of four non-steroidal anti-inflammatory drugs (NSAIDs; flufenamic, meclofenamic, mefenamic and niflumic acids) into human erythrocyte ghost (HEG) membranes over a temperature range from (283.2 to 313.2) K. The proposed method allowed the evaluation and direct analyses of thermodynamic parameters; enthalpy (ΔH W→M ), Gibbs energy (ΔG W→M ) and entropy (ΔS W→M ) changes of the partitioning of NSAIDs into HEG membranes. The partitioning of NSAIDs between polar aqueous phase and non-polar lipid bilayer HEG membrane phase was exothermic with negative (ΔH W→M ) which compensated for the changes in (ΔS W→M ). The negative values of (ΔG W→M ) revealed that the partitioning of NSAIDs into HEG, owing to their transfer from polar aqueous phase and non-polar HEG phase is spontaneous. The enthalpy–entropy correlation analysis resulted in a good linearity that suggests an identical partitioning enthalpy–entropy driven compensation mechanism for the studied NSAIDs
Gunasundari, Elumalai; Senthil Kumar, Ponnusamy
2017-04-01
This study discusses about the biosorption of Cr(VI) ion from aqueous solution using ultrasonic assisted Spirulina platensis (UASP). The prepared UASP biosorbent was characterised by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmet-Teller, scanning electron spectroscopy and energy dispersive X-ray and thermogravimetric analyses. The optimum condition for the maximum removal of Cr(VI) ions for an initial concentration of 50 mg/l by UASP was measured as: adsorbent dose of 1 g/l, pH of 3.0, contact time of 30 min and temperature of 303 K. Adsorption isotherm, kinetics and thermodynamic parameters were calculated. Freundlich model provided the best results for the removal of Cr(VI) ions by UASP. The adsorption kinetics of Cr(VI) ions onto UASP showed that the pseudo-first-order model was well in line with the experimental data. In the thermodynamic study, the parameters like Gibb's free energy, enthalpy and entropy changes were evaluated. This result explains that the adsorption of Cr(VI) ions onto the UASP was exothermic and spontaneous in nature. Desorption of the biosorbent was done using different desorbing agents in which NaOH gave the best result. The prepared material showed higher affinity for the removal of Cr(VI) ions and this may be an alternative material to the existing commercial adsorbents.
Energy Technology Data Exchange (ETDEWEB)
Kilic, Murat; Apaydin-Varol, Esin [Department of Chemical Engineering, Anadolu University, Eskisehir 26470 (Turkey); Puetuen, Ayse E., E-mail: aeputun@anadolu.edu.tr [Department of Chemical Engineering, Anadolu University, Eskisehir 26470 (Turkey)
2011-05-15
This study consists of producing high surface area activated carbon from tobacco residues by chemical activation and its behavior of phenol removal from aqueous solutions. K{sub 2}CO{sub 3} and KOH were used as chemical activation agents and three impregnation ratios (50, 75 and 100 wt.%) were applied on biomass. Maximum BET surface areas of activated carbons were obtained from impregnation with 75 wt.% of K{sub 2}CO{sub 3} and 75 wt.% of KOH as 1635 and 1474 m{sup 2}/g, respectively. Optimum adsorption conditions were determined as a function of pH, adsorbent dosage, initial phenol concentration, contact time and temperature of solution for phenol removal. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as {Delta}G{sup o}, {Delta}H{sup o} and {Delta}S{sup o} were calculated for predicting the nature of adsorption. According to the experimental results, activated carbon prepared from tobacco residue seems to be an effective, low-cost and alternative adsorbent precursor for the removal of phenol from aqueous solutions.
Basha, Shaik; Jaiswar, Santlal; Jha, Bhavanath
2010-09-01
The biosorption equilibrium isotherms of Ni(II) onto marine brown algae Lobophora variegata, which was chemically-modified by CaCl(2) were studied and modeled. To predict the biosorption isotherms and to determine the characteristic parameters for process design, twenty-three one-, two-, three-, four- and five-parameter isotherm models were applied to experimental data. The interaction among biosorbed molecules is attractive and biosorption is carried out on energetically different sites and is an endothermic process. The five-parameter Fritz-Schluender model gives the most accurate fit with high regression coefficient, R (2) (0.9911-0.9975) and F-ratio (118.03-179.96), and low standard error, SE (0.0902-0.0.1556) and the residual or sum of square error, SSE (0.0012-0.1789) values to all experimental data in comparison to other models. The biosorption isotherm models fitted the experimental data in the order: Fritz-Schluender (five-parameter) > Freundlich (two-parameter) > Langmuir (two-parameter) > Khan (three-parameter) > Fritz-Schluender (four-parameter). The thermodynamic parameters such as DeltaG (0), DeltaH (0) and DeltaS (0) have been determined, which indicates the sorption of Ni(II) onto L. variegata was spontaneous and endothermic in nature.
Das, Devlina; Das, Nilanjana; Mathew, Lazar
2010-12-15
Reports are available on silver binding capacity of some microorganisms. However, reports on the equilibrium studies on biosorption of silver by macrofungi are seldom known. The present study was carried out in a batch system using dead biomass of macrofungus Pleurotus platypus for the sorption of Ag(I). P. platypus exhibited the highest silver uptake of 46.7 mg g(-1) of biomass at pH 6.0 in the presence of 200 mg L(-1) Ag(I) at 20°C. Kinetic studies based on fractional power, zero order, first order, pseudo-first order, Elovich, second order and pseudo-second order rate expressions have been carried out. The results showed a very good compliance with the pseudo-first order model. The experimental data were analyzed using two parameter isotherms (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Halsey), three parameter isotherms (Redlich-Peterson, Sips, Khan, Koble-Corrigan, Hill, Toth, Radke-Prausmitz, Jossens, Langmuir-Freundlich), four parameter isotherms (Weber-van Vliet, Fritz-Schlunder, Baudu) and five parameter isotherm (Fritz-Schlunder). Thermodynamic parameters of the biosorption (ΔG, ΔH and ΔS) were also determined. The present study confirmed that macrofungus P. platypus may be used as a cost effective efficient biosorbent for the removal of Ag(I) ions from aqueous solution. Copyright © 2010 Elsevier B.V. All rights reserved.
Roopavathi, K V; Shanthakumar, S
2016-09-01
In the present study, Curcuma longa (turmeric plant) was used as an adsorbent to remove Basic Green 1 (BG) dye. Batch study was carried out to evaluate the adsorption potential of C. longa and influencing factors such as pH (4-10), adsorbent dose (0.2-5 g l-1), initial dye concentration (50-250 mg l-1) and temperature (30-50°C) on dye removal were analysed. The characterisation of adsorbent was carried out using fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) method. Isotherm models that included Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich, and kinetic models such as pseudo first order, pseudo second-order, Elovich and intraparticle diffusion models were studied. A maximum removal percentage (82.76%) of BG dye from aqueous solution was obtained with optimum conditions of pH 7, 1g l-1 adsorbent dose and 30°C temperature, for 100 mg l-1 initial dye concentration. The equilibrium and kinetic study revealed that the experimental data fitted suitably the Freundlich isotherm and Pseudo second order kinetic model. Thermodynamic analysis proved that adsorption system in this study was spontaneous, feasible and endothermic in nature.
Energy Technology Data Exchange (ETDEWEB)
Sengupta, Tapan K., E-mail: tksen@iitk.ac.in; Bhole, Ashish; Shruti, K. S. [HPCL, Department of Aerospace Engineering, IIT Kanpur, Kanpur, UP (India); Sengupta, Aditi [Department of Engineering, University of Cambridge, Cambridge (United Kingdom); Sharma, Nidhi [Graduate Student, HPCL, Department of Aerospace Engineering, IIT Kanpur, Kanpur, UP (India); Sengupta, Soumyo [Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, Ohio 43210 (United States)
2016-09-15
Direct numerical simulations of Rayleigh-Taylor instability (RTI) between two air masses with a temperature difference of 70 K is presented using compressible Navier-Stokes formulation in a non-equilibrium thermodynamic framework. The two-dimensional flow is studied in an isolated box with non-periodic walls in both vertical and horizontal directions. The non-conducting interface separating the two air masses is impulsively removed at t = 0 (depicting a heaviside function). No external perturbation has been used at the interface to instigate the instability at the onset. Computations have been carried out for rectangular and square cross sections. The formulation is free of Boussinesq approximation commonly used in many Navier-Stokes formulations for RTI. Effect of Stokes’ hypothesis is quantified, by using models from acoustic attenuation measurement for the second coefficient of viscosity from two experiments. Effects of Stokes’ hypothesis on growth of mixing layer and evolution of total entropy for the Rayleigh-Taylor system are reported. The initial rate of growth is observed to be independent of Stokes’ hypothesis and the geometry of the box. Following this stage, growth rate is dependent on the geometry of the box and is sensitive to the model used. As a consequence of compressible formulation, we capture pressure wave-packets with associated reflection and rarefaction from the non-periodic walls. The pattern and frequency of reflections of pressure waves noted specifically at the initial stages are reflected in entropy variation of the system.
Energy Technology Data Exchange (ETDEWEB)
Puigdomenech, I [Studsvik AB, Nykoeping (Sweden); Bruno, J [Intera Information Technologies SL, Cerdanyola (Spain)
1995-04-01
Thermodynamic data has been selected for solids and aqueous species of technetium. Equilibrium constants have been calculated in the temperature range 0 to 300 deg C at a pressure of 1 bar for T<100 deg C and at the steam saturated pressure at higher temperatures. For aqueous species, the revised Helgeson-Kirkham-Flowers model is used for temperature extrapolations. The data base contains a large amount of estimated data, and the methods used for these estimations are described in detail. A new equation is presented that allows the estimation of {Delta}{sub r}Cdeg{sub pm} values for mononuclear hydrolysis reactions. The formation constants for chloro complexes of Tc(V) and Tc(IV), whose existence is well established, have been estimated. The majority of entropy and heat capacity values in the data base have also been estimated, and therefore temperature extrapolations are largely based on estimations. The uncertainties derived from these calculations are described. Using the data base developed in this work, technetium solubilities have been calculated as a function of temperature for different chemical conditions. The implications for the mobility of Tc under nuclear repository conditions are discussed. 70 refs.
International Nuclear Information System (INIS)
Alonso, Regina P.
1997-01-01
Two regions in the zirconium-platinum system (Zr-Pt) were investigated, namely, the zirconium rich and the platinum rich regions. With this purpose, five alloys were obtained. The performed experiences consisted on heat treatments and electrical resistivity variations with temperature measurements. The appearing phases were analyzed by optical and scanning electron microscopy (SEM), quantitative microanalysis and X-ray diffraction techniques. Besides that, the existing phases in the rich zirconium region between 0 and 50 % at. Pt were thermodynamically modelled and the resulting diagram was calculated by means of the Thermocalc computational program. Several proposals were formulated: a) A change in the eutectoid transformation temperature βZr ↔ αZr + pp (800 C degrees according to this work); b) The existence of the phase Zr 3 Pt in the equilibrium diagram; c) The existence of the peritectic transformation Liquid + Zr 5 Pt 3 ↔ Zr 3 Pt; d) The occurrence of the two - phases region ZrPt 3 + ZrPt 8 between 1050 and 1320 C degrees, and finally; e) The occurrence of the peritectic transformation ZrPt 3 + Liquid ↔ γPt was verified. (author)
Holographic dark energy: Quantum correlations against thermodynamical description
International Nuclear Information System (INIS)
Horvat, R.
2008-01-01
Classical and quantum entropic properties of holographic dark energy (HDE) are considered in view of the fact that its entropy is far more restrictive than the entropy of a black hole of the same size. In cosmological settings (in which HDE is promoted to a plausible candidate for being the dark energy of the universe), HDE should be viewed as a combined state composed of the event horizon and the stuff inside the horizon. By any interaction of the subsystems, the horizon and the interior become entangled, raising thereby a possibility that their quantum correlations be responsible for the almost purity of the combined state. Under this circumstances, the entanglement entropy is almost the same for both subsystems, being also of the same order as the thermal (coarse grained) entropy of the interior or the horizon. In the context of thermodynamics, however, only additive coarse grained entropies matter, so we use these entropies to test the generalized second law (GSL) of gravitational thermodynamics in this framework. While we find that the original Li's model passes the GSL test for a special choice of parameters, in a saturated model with the choice for the IR cutoff in the form of the Hubble parameter, the GSL always breaks down
Thermodynamic analysis of a liquid air energy storage system
International Nuclear Information System (INIS)
Guizzi, Giuseppe Leo; Manno, Michele; Tolomei, Ludovica Maria; Vitali, Ruggero Maria
2015-01-01
The rapid increase in the share of electricity generation from renewable energy sources is having a profound impact on the power sector; one of the most relevant effects of this trend is the increased importance of energy storage systems, which can be used to smooth out peaks and troughs of production from renewable energy sources. Besides their role in balancing the electric grid, energy storage systems may provide also several other useful services, such as price arbitrage, stabilizing conventional generation, etc.; therefore, it is not surprising that many research projects are under way in order to explore the potentials of new technologies for electric energy storage. This paper presents a thermodynamic analysis of a cryogenic energy storage system, based on air liquefaction and storage in an insulated vessel. This technology is attractive thanks to its independence from geographical constraints and because it can be scaled up easily to grid-scale ratings, but it is affected by a low round-trip efficiency due to the energy intensive process of air liquefaction. The present work aims to assess the efficiency of such a system and to identify if and how it can achieve an acceptable round-trip efficiency (in the order of 50–60%).
Energy Current Cumulants in One-Dimensional Systems in Equilibrium
Dhar, Abhishek; Saito, Keiji; Roy, Anjan
2018-06-01
A recent theory based on fluctuating hydrodynamics predicts that one-dimensional interacting systems with particle, momentum, and energy conservation exhibit anomalous transport that falls into two main universality classes. The classification is based on behavior of equilibrium dynamical correlations of the conserved quantities. One class is characterized by sound modes with Kardar-Parisi-Zhang scaling, while the second class has diffusive sound modes. The heat mode follows Lévy statistics, with different exponents for the two classes. Here we consider heat current fluctuations in two specific systems, which are expected to be in the above two universality classes, namely, a hard particle gas with Hamiltonian dynamics and a harmonic chain with momentum conserving stochastic dynamics. Numerical simulations show completely different system-size dependence of current cumulants in these two systems. We explain this numerical observation using a phenomenological model of Lévy walkers with inputs from fluctuating hydrodynamics. This consistently explains the system-size dependence of heat current fluctuations. For the latter system, we derive the cumulant-generating function from a more microscopic theory, which also gives the same system-size dependence of cumulants.
Directory of Open Access Journals (Sweden)
SLOBODAN P. SERBANOVIC
2000-12-01
Full Text Available The Kojima-Moon-Ochi (KMO thermodynamic consistency test of vapourliquid equilibrium (VLE measurements for 32 isothermal data sets of binary systems of various complexity was applied using two fitting equations: the Redlich-Kister equation and the Sum of Symmetrical Functions. It was shown that the enhanced reliability of the fitting of the experimental data can change the conclusions drawn on their thermodynamic consistency in those cases of VLE data sets that are estimated to be near the border of consistency.
Directory of Open Access Journals (Sweden)
R.A.G. Sé
2002-04-01
Full Text Available The NRTL (nonrandom, two-liquid model, expressed in mass fraction instead of mole fraction, was used to correlate liquid-liquid equilibria for aqueous two-phase polymer-salt solutions. New interaction energy parameters for this model were determined using reported data on the water + poly(ethylene glycol + salt systems, with different molecular masses for PEG and the salts potassium phosphate, sodium sulfate, sodium carbonate and magnesium sulfate. The correlation of liquid-liquid equilibrium is quite satisfactory.
Directory of Open Access Journals (Sweden)
Peter W. Egolf
2018-02-01
Full Text Available The extended thermodynamics of Tsallis is reviewed in detail and applied to turbulence. It is based on a generalization of the exponential and logarithmic functions with a parameter q. By applying this nonequilibrium thermodynamics, the Boltzmann-Gibbs thermodynamic approach of Kraichnan to 2-d turbulence is generalized. This physical modeling implies fractional calculus methods, obeying anomalous diffusion, described by Lévy statistics with q < 5/3 (sub diffusion, q = 5/3 (normal or Brownian diffusion and q > 5/3 (super diffusion. The generalized energy spectrum of Kraichnan, occurring at small wave numbers k, now reveals the more general and precise result k−q. This corresponds well for q = 5/3 with the Kolmogorov-Oboukov energy spectrum and for q > 5/3 to turbulence with intermittency. The enstrophy spectrum, occurring at large wave numbers k, leads to a k−3q power law, suggesting that large wave-number eddies are in thermodynamic equilibrium, which is characterized by q = 1, finally resulting in Kraichnan’s correct k−3 enstrophy spectrum. The theory reveals in a natural manner a generalized temperature of turbulence, which in the non-equilibrium energy transfer domain decreases with wave number and shows an energy equipartition law with a constant generalized temperature in the equilibrium enstrophy transfer domain. The article contains numerous new results; some are stated in form of eight new (proven propositions.
Physics of future equilibrium state of nuclear energy utilization
International Nuclear Information System (INIS)
Sekimoto, H.
1994-01-01
The governing equations for future equilibrium nuclear state are presented and their characteristics are discussed. These equations are solved for several typical cases. In the present study on the equilibrium state, two coincidences are found. The first is the coincidence on the neutron balance performed by the nuclides satisfying the equilibrium condition. The finite neutron multiplication factor is near unity. The second is the coincidence on the toxicity. The produced long-life fission product toxicity is near the incinerated natural fuel toxicity. (author). 2 refs., 2 tabs., 4 figs
Manera, Christian; Tonello, Andrezza Piroli; Perondi, Daniele; Godinho, Marcelo
2018-03-23
In this work, the adsorption of Acid Black 210 (AB210) and Acid Red 357 (AR357) onto activated carbon prepared from leather shaving wastes (ACLW) was investigated. The activated carbon presented a surface area of 800.4 m²/g with an average pore size of 1.27 nm. The kinetic study showed that the adsorption of both dyes followed the Elovich kinetic model while the AB210 and AR357 isotherm data were well described by the Langmuir and BET models, respectively. Furthermore, the Boyd plot revealed that the adsorption of the leather dyes on activated carbon was mainly governed by film diffusion. The pH had a strong influence on the adsorption, and the higher amounts of dye adsorbed were obtained at pH 2. The obtained activated carbon exhibited a high monolayer adsorption capacity of 573.9 and 204.4 mg/g for AB210 and AR357, respectively. Its high capacity is mainly attributed to its basicity (0.17 mmol/g) and high surface area. Desorption efficiency of the spent activated carbon was found to be 54.3% and 43.0% for AB210 and AR357, respectively. The spontaneity of the process was demonstrated by the negative values of the Gibbs free energy change.
Adsorption equilibrium and thermodynamics of CO{sub 2} and CH{sub 4} on carbon molecular sieves
Energy Technology Data Exchange (ETDEWEB)
Song, Xue [College of Resource and Environmental Science, Chongqing University, Chongqing, 400044 (China); State key laboratory of coal and disaster and control, Chongqing University, Chongqing University, Chongqing, 400044 (China); Wang, Li’ao, E-mail: wangliao@cqu.edu.cn [College of Resource and Environmental Science, Chongqing University, Chongqing, 400044 (China); State key laboratory of coal and disaster and control, Chongqing University, Chongqing University, Chongqing, 400044 (China); Ma, Xu; Zeng, Yunmin [College of Resource and Environmental Science, Chongqing University, Chongqing, 400044 (China); State key laboratory of coal and disaster and control, Chongqing University, Chongqing University, Chongqing, 400044 (China)
2017-02-28
Highlights: • Impacts of pore structure on adsorption capacity of CO{sub 2} and CH{sub 4} on CMS were studied. • Thermodynamic properties of CO{sub 2} and CH{sub 4} at zero surface coverage were analyzed. • Variation of entropy change and Gibbs free energy with surface loading was explored. - Abstract: Carbon molecular sieves (CMS) are widely used in the separation of dioxide carbon and methane. In this research, three commercial CMS were utilized to analyze the pore structure and chemical properties. The adsorption isotherms of CO{sub 2} and CH{sub 4} were studied at 298 K, 308 K and 318 K over the pressure range of 0–1 MPa by an Intelligent Gravimetric analysis (IGA-100B, UK). Langmuir model was adopted to fit the experimental data. The working capacity and selectivity were employed to evaluate the adsorbents. The adsorption thermodynamics were discussed. The adsorbed amounts of both CO{sub 2} and CH{sub 4} are found to be highly related with the BET specific surface area and the volume of micropores, and also are interrelated with the total pore volume and micropore surface area. The standard enthalpy change (ΔH{sup Θ}), standard Gibbs free energy (ΔG{sup Θ}) and standard entropy change (ΔS{sup Θ}) at zero surface loading are negative, manifesting the adsorption process is exothermic and spontaneous, and the system tends to be ordered. With the increasing surface coverage, the absolute values of Gibbs free energy (ΔG) decrease whereas the absolute values of enthalpy change (ΔH) and entropy change(ΔS) increase. This indicates that as the adsorbed amount increases, the degree of the spontaneity reduces, the intermolecular forces among the adsorbate molecules increase, the orderliness of the system improves and the adsorbed amount approaches the maximum adsorbed capacity.
Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa
2009-07-30
The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g(-1) for 10 g L(-1) of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy (DeltaS degrees) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 degrees C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.
International Nuclear Information System (INIS)
Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa
2009-01-01
The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g -1 for 10 g L -1 of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (ΔG o ), enthalpy (ΔH o ), and entropy (ΔS o ) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 o C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.
Energy Technology Data Exchange (ETDEWEB)
Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri [Department of Chemistry, Karadeniz Technical University, Faculty of Arts and Sciences, 61080 Trabzon (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Department of Chemistry, Erciyes University, Faculty of Arts and Sciences, 38039 Kayseri (Turkey)
2009-07-30
The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g{sup -1} for 10 g L{sup -1} of a-WM concentration. Thermodynamic parameters including the Gibbs free energy ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}), and entropy ({Delta}S{sup o}) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 {sup o}C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.
Mertens, Christopher J.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Wintersteiner, Peter P.; Picard, Richard H.; Winick, Jeremy R.; Gordley, Larry L.; Russell, James M., III
2002-01-01
The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment was launched onboard the TIMED satellite in December, 2001. SABER is designed to provide measurements of the key radiative and chemical sources and sinks of energy in the mesosphere and lower thermosphere (MLT). SABER measures Earth limb emission in 10 broadband radiometer channels ranging from 1.27 micrometers to 17 micrometers. Measurements are made both day and night over the latitude range from 54 deg. S to 87 deg. N with alternating hemisphere coverage every 60 days. In this paper we concentrate on retrieved profiles of kinetic temperature (T(sub k)) and CO2 volume mixing ratio (vmr), inferred from SABER-observed 15 micrometer and 4.3 micrometer limb emissions, respectively. SABER-measured limb radiances are in non-local thermodynamic equilibrium (non-LTE) in the MLT region. The complexity of non-LTE radiation transfer combined with the large volume of data measured by SABER requires new retrieval approaches and radiative transfer techniques to accurately and efficiently retrieve the data products. In this paper we present the salient features of the coupled non-LTE T(sub k)/CO2 retrieval algorithm, along with preliminary results.
Directory of Open Access Journals (Sweden)
Matthew Menkiti
2018-03-01
Full Text Available Adsorptive component of produced water (PW coagulation using Tympanotonos Fuscatus coagulant (TFC was studied. Influence of the following parameters: pH, coagulant dose, settling time, and temperature were investigated. The functional group, crystalline nature, morphological observation and thermal characteristics of the sample were evaluated. Equilibrium data were analyzed using Langmuir, Freundlich, Temkin, Frumkin, and Dubinin-Radushkevich (D-R adsorption isotherms. The kinetics data were fitted to reversible first order, pseudo-first-order, pseudo-second-order, elovich, intra-particle diffusion and Boyd kinetic models. Adsorption Gibbs energy, enthalpy and entropy were evaluated. Equilibrium data best fitted the Langmuir isotherm (R2 > 0.99; X2 < 1.6; SSE < 1.6. Reversible first order model correlated best to the kinetics data. The values of process average Gibb's free energy, enthalpy and entropy were 30.35, 27.88 and 0.1891 kJ/mol, respectively. The process was spontaneous, feasible and endothermic in nature. The maximum efficiency of 83.1% was favored at pH 2.0. This study indicated significant adsorptive component, while using Tympanotonos Fuscatus extract as readily available, renewable, ecofriendly bio – coagulant for efficient treatments of PW.
Synthesis and Thermodynamic Studies of Physisorptive Energy Storage Materials
Stadie, Nicholas
Physical adsorption of hydrogen or other chemical fuels on the surface of carbonaceous materials offers a promising avenue for energy storage applications. The addition of a well-chosen sorbent material to a compressed gas tank increases the volumetric energy density of the system while still permitting fast refueling, simplicity of design, complete reversibility, high cyclability, and low overall cost of materials. While physical adsorption is most effective at temperatures below ambient, effective storage technologies are possible at room temperature and modestly high pressure. A volumetric Sieverts apparatus was designed, constructed, and commissioned to accurately measure adsorption uptake at high pressures and an appropriate thermodynamic treatment of the experimental data is presented. In Chapter 1, the problem of energy storage is introduced in the context of hydrogen as an ideal alternative fuel for future mobile vehicle applications, and with methane in mind as a near-term solution. The theory of physical adsorption that is relevant to this work is covered in Chapter 2. In-depth studies of two classes of materials are presented in the final chapters. Chapter 3 presents a study of the dissociative "hydrogen spillover" effect in the context of its viability as a practical hydrogen storage solution at room temperature. Chapters 4-5 deal with zeolite-templated carbon, an extremely high surface-area material which shows promise for hydrogen and methane storage applications. Studies of hydrogen adsorption at high pressure (Chapter 4) and anomalous thermodynamic properties of methane adsorption (Chapter 5) on ZTCs are presented. The concluding chapter discusses the impact of and possible future directions for this work.
Thermodynamic properties of organic compounds estimation methods, principles and practice
Janz, George J
1967-01-01
Thermodynamic Properties of Organic Compounds: Estimation Methods, Principles and Practice, Revised Edition focuses on the progression of practical methods in computing the thermodynamic characteristics of organic compounds. Divided into two parts with eight chapters, the book concentrates first on the methods of estimation. Topics presented are statistical and combined thermodynamic functions; free energy change and equilibrium conversions; and estimation of thermodynamic properties. The next discussions focus on the thermodynamic properties of simple polyatomic systems by statistical the
Energy Technology Data Exchange (ETDEWEB)
De Giacomo, A. [Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari (Italy); Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Dell' Aglio, M. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Gaudiuso, R., E-mail: rosalba.gaudiuso@ba.imip.cnr.it [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Santagata, A. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Potenza, Via S. Loja, Zona Ind., 85050 Tito Scalo (PZ) (Italy); Senesi, G.S. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Rossi, M.; Ghiara, M.R. [Department of Earth Sciences, University of Naples ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy); Capitelli, F. [Institute of Crystallography - CNR, Via Salaria Km 29.300, 00015 Monterotondo (Roma) (Italy); De Pascale, O. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy)
2012-04-04
Graphical abstract: Self-calibrated analytical techniques based on the approximation of Local Thermodynamic Equilibrium (LTE) have been employed for the analysis of gemstones and copper-based alloys by LIBS (Laser Induced Breakdown Spectroscopy), with a special focus on LTE conditions in laser induced plasmas. Highlights: Black-Right-Pointing-Pointer Discussion of Local Thermodynamic Equilibrium (LTE) condition in laser-induced plasmas. Black-Right-Pointing-Pointer LIBS enables elemental analysis with self-calibrated LTE-based methods. Black-Right-Pointing-Pointer Be detection in alexandrite gemstone is made possible by LIBS. - Abstract: Laser Induced Breakdown Spectroscopy (LIBS) is an appealing technique to study laser-induced plasmas (LIPs), both from the basic diagnostics point of view and for analytical applications. LIPs are complex dynamic systems, expanding at supersonic velocities and undergoing a transition between different plasma regimes. If the Local Thermodynamic Equilibrium (LTE) condition is valid for such plasmas, several analytical methods can be employed and fast quantitative analyses can be performed on a variety of samples. In the present paper, a discussion about LTE is carried out and an innovative application to the analysis of the alexandrite gemstone is presented. In addition, a study about the influence of plasma parameters on the performance of LTE-based methods is reported for bronze and brass targets.
Liu, Jingyong; Fu, Jiewen; Ning, Xun'an; Sun, Shuiyu; Wang, Yujie; Xie, Wuming; Huang, Shaosong; Zhong, Sheng
2015-09-01
The effects of different chlorides and operational conditions on the distribution and speciation of six heavy metals (Pb, Zn, Cr, Cu, Mn and Ni) during sludge incineration were investigated using a simulated laboratory tubular-furnace reactor. A thermodynamic equilibrium investigation using the FactSage software was performed to compare the experimental results. The results indicate that the volatility of the target metals was enhanced as the chlorine concentration increased. Inorganic-Cl influenced the volatilization of heavy metals in the order of Pb>Zn>Cr>Cu>Mn>Ni. However, the effects of organic-Cl on the volatility of Mn, Pb and Cu were greater than the effects on Zn, Cr and Ni. With increasing combustion temperature, the presence of organic-Cl (PVC) and inorganic-Cl (NaCl) improved the transfer of Pb and Zn from bottom ash to fly ash or fuse gas. However, the presence of chloride had no obvious influence on Mn, Cu and Ni. Increased retention time could increase the volatilization rate of heavy metals; however, this effect was insignificant. During the incineration process, Pb readily formed PbSiO4 and remained in the bottom ash. Different Pb compounds, primarily the volatile PbCl2, were found in the gas phase after the addition of NaCl; the dominant Pb compounds in the gas phase after the addition of PVC were PbCl2, Pb(ClO4)2 and PbCl2O4. Copyright © 2015. Published by Elsevier B.V.
Main theorems of thermodynamics focused on future energy supply
Energy Technology Data Exchange (ETDEWEB)
Knizia, K
1983-09-01
Proceeding from the ethical aim to minimize sufferings, we have to develop rules of conduct which take into account the effects of our actions which in our complex world reach spatially as well as temporally further than in previous times. The basic laws of nature which govern our activities include the first and the second main theorems of thermodynamics. It is especially the second main theorem which also represent the creative principle of shaping and maintaining order and structures. In general, this is achieved by the use of the production factors: energy - information - matter. This also applies to the human creativity, including specific adjustment of these production factors related to man and his environment. It is only the correct use which can achieve an adequate supply of goods for a still growing world population, together with its peaceful and humane numerical stabilisation, satisfactory environment protection and careful consumption of raw material reserves.
International Nuclear Information System (INIS)
Elsner, Albrecht
2012-01-01
Gibbs's work on the thermodynamic properties of substances presented a complete thermodynamic theory. The formulations of the entropy S and internal energy U as extensive quantities allow the zeros of the real gas to be given: S=0 at absolute zero (Nernst, Planck) and U=0 at the critical point. Consequently, every thermodynamic function is unique and absolutely specified. Interdependences among quantities such as temperature, vapor pressure, chemical potential, volume, entropy, internal energy, and heat capacity are likewise unique and numerically well defined. This is shown for the saturated fluid, water, in the region between absolute zero and the critical point. As a consequence of the calculation of the chemical potential, it follows that the free particle flow in an inhomogeneous system is essentially governed by the difference in chemical potential, and not through the difference in pressure, this effect being of importance for meteorology and oceanography.
Forces and energy dissipation in inhomogeneous non-equilibrium superconductors
International Nuclear Information System (INIS)
Poluehktov, Yu.M.; Slezov, V.V.
1987-01-01
The phenomenological theory of volume forces and dissipation processes in inhomogeneous non-equilibrium superconductors near temperature transition from the normal to superconducting state is constructed. The approach is based on application of dynamic equations of superconductivity formulated on the basis of the Lagrangian formalism. These equations are generalized the Ginzburg-Landau theory in the nonstationary non-equilibrium case for ''foul'' superconductors. The value estimations of volume forces arising in inhomogeneities during relaxation of an order parameter and when the electrical field is penetrated into the superconductor, are given
Mavris, Dimitri; Roth, Bryce; McDonald, Rob
2002-01-01
The objective of this report is to provide a tool to facilitate the application of thermodynamic work potential methods to aircraft and engine analysis. This starts with a discussion of the theoretical background underlying these methods, which is then used to derive various equations useful for thermodynamic analysis of aircraft engines. The work potential analysis method is implemented in the form of a set of working charts and tables that can be used to graphically evaluate work potential stored in high-enthalpy gas. The range of validity for these tables is 300 to 36,000 R, pressures between between 0.01 atm and 100 atm, and fuel-air ratios from zero to stoichiometric. The derivations and charts assume mixtures of Jet-A and air as the working fluid. The thermodynamic properties presented in these charts were calculated based upon standard thermodynamic curve fits.
Approach to equilibrium in high energy heavy ion collisions
International Nuclear Information System (INIS)
Zimanyi, J.
1981-01-01
With the aim to clarify somewhat the question of equilibration in the following we investigate the approach to equilibrium of particle composition and momentum distribution of the particles within the firecloud formed in the central collision of energetic heavy ions. (orig.)
Thermodynamic Derivation of the Activation Energy for Ice Nucleation
Barahona, D.
2015-01-01
Cirrus clouds play a key role in the radiative and hydrological balance of the upper troposphere. Their correct representation in atmospheric models requires an understanding of the microscopic processes leading to ice nucleation. A key parameter in the theoretical description of ice nucleation is the activation energy, which controls the flux of water molecules from the bulk of the liquid to the solid during the early stages of ice formation. In most studies it is estimated by direct association with the bulk properties of water, typically viscosity and self-diffusivity. As the environment in the ice-liquid interface may differ from that of the bulk, this approach may introduce bias in calculated nucleation rates. In this work a theoretical model is proposed to describe the transfer of water molecules across the ice-liquid interface. Within this framework the activation energy naturally emerges from the combination of the energy required to break hydrogen bonds in the liquid, i.e., the bulk diffusion process, and the work dissipated from the molecular rearrangement of water molecules within the ice-liquid interface. The new expression is introduced into a generalized form of classical nucleation theory. Even though no nucleation rate measurements are used to fit any of the parameters of the theory the predicted nucleation rate is in good agreement with experimental results, even at temperature as low as 190 K, where it tends to be underestimated by most models. It is shown that the activation energy has a strong dependency on temperature and a weak dependency on water activity. Such dependencies are masked by thermodynamic effects at temperatures typical of homogeneous freezing of cloud droplets; however, they may affect the formation of ice in haze aerosol particles. The new model provides an independent estimation of the activation energy and the homogeneous ice nucleation rate, and it may help to improve the interpretation of experimental results and the
Sitnova, T. M.; Mashonkina, L. I.; Ryabchikova, T. A.
2016-09-01
We construct a model atom for Ti I-II using more than 3600 measured and predicted energy levels of Ti I and 1800 energy levels of Ti II, and quantum mechanical photoionization cross-sections. Non-local thermodynamical equilibrium (NLTE) line formation for Ti I and Ti II is treated through a wide range of spectral types from A to K, including metal-poor stars with [Fe/H] down to -2.6 dex. NLTE leads to weakened Ti I lines and positive abundance corrections. The magnitude of NLTE corrections is smaller compared to the literature data for FGK atmospheres. NLTE leads to strengthened Ti II lines and negative NLTE abundance corrections. For the first time, we have performed NLTE calculations for Ti I-II in the 6500 ≤ Teff ≤ 13 000 K range. For four A-type stars, we derived in LTE an abundance discrepancy of up to 0.22 dex between Ti I and Ti II, which vanishes in NLTE. For four other A-B stars, with only Ti II lines observed, NLTE leads to a decrease of line-to-line scatter. An efficiency of inelastic Ti I + H I collisions was estimated from an analysis of Ti I and Ti II lines in 17 cool stars with -2.6 ≤ [Fe/H] ≤ 0.0. Consistent NLTE abundances from Ti I and Ti II were obtained by applying classical Drawinian rates for the stars with log g ≥ 4.1, and neglecting inelastic collisions with H I for the very metal-poor (VMP) giant HD 122563. For the VMP turn-off stars ([Fe/H] ≤ -2 and log g ≤ 4.1), we obtained the positive abundance difference Ti I-II already in LTE, which increases in NLTE. Accurate collisional data for Ti I and Ti II are necessary to help solve this problem.
Entropy equilibrium equation and dynamic entropy production in environment liquid
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The entropy equilibrium equation is the basis of the nonequilibrium state thermodynamics. But the internal energy implies the kinetic energy of the fluid micelle relative to mass center in the classical entropy equilibrium equation at present. This internal energy is not the mean kinetic energy of molecular movement in thermodynamics. Here a modified entropy equilibrium equation is deduced, based on the concept that the internal energy is just the mean kinetic energy of the molecular movement. A dynamic entropy production is introduced into the entropy equilibrium equation to describe the dynamic process distinctly. This modified entropy equilibrium equation can describe not only the entropy variation of the irreversible processes but also the reversible processes in a thermodynamic system. It is more reasonable and suitable for wider applications.
Long-term equilibrium effects of constraints in energy supply
International Nuclear Information System (INIS)
Brookes, L.G.
1984-01-01
The subject is covered in sections, entitled: introduction; the economic role of energy; the economics of energy price; a first attempt to model long term effects (energy consumption and economic activity); what is a price hike (energy supply and demand functions before and after price hike); modelling energy price hikes; implications and lessons for nuclear energy; the present reality. (U.K.)
Statistical Thermodynamics and Microscale Thermophysics
Carey, Van P.
1999-08-01
Many exciting new developments in microscale engineering are based on the application of traditional principles of statistical thermodynamics. In this text Van Carey offers a modern view of thermodynamics, interweaving classical and statistical thermodynamic principles and applying them to current engineering systems. He begins with coverage of microscale energy storage mechanisms from a quantum mechanics perspective and then develops the fundamental elements of classical and statistical thermodynamics. Subsequent chapters discuss applications of equilibrium statistical thermodynamics to solid, liquid, and gas phase systems. The remainder of the book is devoted to nonequilibrium thermodynamics of transport phenomena and to nonequilibrium effects and noncontinuum behavior at the microscale. Although the text emphasizes mathematical development, Carey includes many examples and exercises to illustrate how the theoretical concepts are applied to systems of scientific and engineering interest. In the process he offers a fresh view of statistical thermodynamics for advanced undergraduate and graduate students, as well as practitioners, in mechanical, chemical, and materials engineering.
Energy Technology Data Exchange (ETDEWEB)
Pinto, Leandro F.; Segalen da Silva, Diogo Italo [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Rosa da Silva, Fabiano; Ramos, Luiz P. [Department of Chemistry, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Ndiaye, Papa M. [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Corazza, Marcos L., E-mail: corazza@ufpr.br [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil)
2012-01-15
Highlights: > We measured phase behavior for the system involving {l_brace}CO{sub 2} + biodiesel + methanol{r_brace}. > The saturation pressures were obtained using a variable-volume view cell. > The experimental data were modeled using PR-vdW2 and PR-WS equations of state. - Abstract: The main objective of this work was to investigate the high pressure phase behavior of the binary systems {l_brace}CO{sub 2}(1) + methanol(2){r_brace} and {l_brace}CO{sub 2}(1) + soybean methyl esters (biodiesel)(2){r_brace} and the ternary system {l_brace}CO{sub 2}(1) + biodiesel(2) + methanol(3){r_brace} were determined. Biodiesel was produced from soybean oil, purified, characterized and used in this work. The static synthetic method, using a variable-volume view cell, was employed to obtain the experimental data in the temperature range of (303.15 to 343.15) K and pressures up to 21 MPa. The mole fractions of carbon dioxide were varied according to the systems as follows: (0.2383 to 0.8666) for the binary system {l_brace}CO{sub 2}(1) + methanol(2){r_brace}; (0.4201 to 0.9931) for the binary system {l_brace}CO{sub 2}(1) + biodiesel(2){r_brace}; (0.4864 to 0.9767) for the ternary system {l_brace}CO{sub 2}(1) + biodiesel(2) + methanol(3){r_brace} with a biodiesel to methanol molar ratio of (1:3); and (0.3732 to 0.9630) for the system {l_brace}CO{sub 2} + biodiesel + methanol{r_brace} with a biodiesel to methanol molar ratio of (8:1). For these systems, (vapor + liquid), (liquid + liquid), (vapor + liquid + liquid) transitions were observed. The phase equilibrium data obtained for the systems were modeled using the Peng-Robinson equation of state with the classical van der Waals (PR-vdW2) and Wong-Sandler (PR-WS) mixing rules. Both thermodynamic models were able to satisfactorily correlate the phase behavior of the systems investigated and the PR-WS presented the best performance.
Energy taxes and wages in a general equilibrium model of production
International Nuclear Information System (INIS)
Thompson, H.
2000-01-01
Energy taxes are responsible for a good deal of observed differences in energy prices across states and countries. They alter patterns of production and income distribution. The present paper examines the potential of energy taxes to lower wages in a general equilibrium model of production with capital, labour and energy inputs. (Author)
Energy Technology Data Exchange (ETDEWEB)
Koeijer, Gelein M. de
2002-05-01
In this thesis the entropy production rates of diabatic distillation columns and a SO{sub 2} converter were minimised. This is the same as maximising the second law energy efficiency of the systems. The development of chemical industry can be made more sustainable by knowing this minimum. We found that the entropy production rate of distillation could be reduced up to 50 %. In order to achieve this reduction, heat exchangers were added on each tray. The characteristics of an optimum distillation column were presented. Furthermore, the entropy production rate of a SO{sub 2} converter was reduced with 16.7 % by altering the heights of catalytic beds, transfer areas of heat exchangers, and temperature differences over heat exchangers. These reductions show that there is still a large improvement potential in chemical industry. By applying the improved operations the world oil production can be reduced in the order of magnitude of 1 %. A similar reduction in the emission of the greenhouse gas CO{sub 2} can be expected. For deriving the entropy production rate in a systematic manner the theory of irreversible thermodynamics was useful. A simpler and a more complicated equation for the entropy production rate of distillation were derived. The simpler equation used only one force-flux product. It was suitable for minimisation of the entropy production rate of columns with the assumption of equilibrium between the outlets on each tray. The more complicated equation was able to describe satisfactorily the entropy production rate of an experimental column that separated the non-ideal mixture water-ethanol. It was next used to derive an extended set of transport equations for distillation, that includes the interface and the Soret effect (or thermal diffusion). Finally, irreversible thermodynamics was used to describe the contribution to the entropy production rate of heat transfer in heat exchangers. This contribution had a significant impact on the results of the
International Nuclear Information System (INIS)
Lu, Yingying; Liu, Yu; Zhou, Meifang
2017-01-01
This paper explores the rebound effect of different energy types in China based on a static computable general equilibrium model. A one-off 5% energy efficiency improvement is imposed on five different types of energy, respectively, in all the 135 production sectors in China. The rebound effect is measured both on the production level and on the economy-wide level for each type of energy. The results show that improving energy efficiency of using electricity has the largest positive impact on GDP among the five energy types. Inter-fuel substitutability does not affect the macroeconomic results significantly, but long-run impact is usually greater than the short-run impact. For the exports-oriented sectors, those that are capital-intensive get big negative shock in the short run while those that are labour-intensive get hurt in the long run. There is no “backfire” effect; however, improving efficiency of using electricity can cause negative rebound, which implies that improving the energy efficiency of using electricity might be a good policy choice under China's current energy structure. In general, macro-level rebound is larger than production-level rebound. Primary energy goods show larger rebound effect than secondary energy goods. In addition, the paper points out that the policy makers in China should look at the rebound effect in the long term rather than in the short term. The energy efficiency policy would be a good and effective policy choice for energy conservation in China when it still has small inter-fuel substitution. - Highlights: • Primary energy goods show larger rebound effect than secondary energy goods. • Improving efficiency of using electricity can cause negative rebound. • The energy efficiency policy would be an effective policy choice for China. • Policy-makers should consider the rebound effect in the longer term.
International Nuclear Information System (INIS)
Karami, K.; Ghaffari, S.
2010-01-01
We investigate the validity of the generalized second law of thermodynamics in a non-flat FRW universe containing the interacting polytropic dark energy with cold dark matter. The boundary of the universe is assumed to be enclosed by the dynamical apparent horizon. We show that for this model under thermal equilibrium with the Hawking radiation, the generalized second law is always satisfied throughout the history of the universe for any spatial curvature, independently of the deceleration parameter.
Energy Technology Data Exchange (ETDEWEB)
Karami, K., E-mail: KKarami@uok.ac.i [Department of Physics, University of Kurdistan, Pasdaran St., Sanandaj (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Ghaffari, S. [Department of Physics, University of Kurdistan, Pasdaran St., Sanandaj (Iran, Islamic Republic of)
2010-05-03
We investigate the validity of the generalized second law of thermodynamics in a non-flat FRW universe containing the interacting polytropic dark energy with cold dark matter. The boundary of the universe is assumed to be enclosed by the dynamical apparent horizon. We show that for this model under thermal equilibrium with the Hawking radiation, the generalized second law is always satisfied throughout the history of the universe for any spatial curvature, independently of the deceleration parameter.
Directory of Open Access Journals (Sweden)
Swarup Biswas
2015-01-01
Full Text Available Rubber wood sawdust was carbonized into charcoal by chemical treatment which was used for removal of lead ion from aqueous solution. The work involves batch experiments to investigate the pH effect, initial concentration of adsorbate, contact time, and adsorbent dose. Experimental data confirmed that the adsorption capacities increased with increasing inlet concentration and bed height and decreased with increasing flow rate. Adsorption results showed a maximum adsorption capacity of 37 mg/g at 308 K. Langmuir, Freundlich, and Temkin model adsorption isotherm models were applied to analyze the process where Temkin was found as a best fitted model for present study. Simultaneously kinetics of adsorption like pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were investigated. Thermodynamic parameters were used to analyze the adsorption experiment. Fourier transform infrared spectroscopy, scanning electron microscope, and energy dispersive X-ray spectroscopy confirmed the batch adsorption of lead ion onto chemically carbonized rubber wood sawdust.
Directory of Open Access Journals (Sweden)
Susan Azizi
2017-06-01
Full Text Available In the present study, ZnO nanoparticles (NPs were synthesized in zerumbone solution by a green approach and appraised for their ability to absorb Pb(II ions from aqueous solution. The formation of as-synthesized NPs was established by X-ray diffraction (XRD, Transmission Electron Microscopy (TEM, and UV–visible studies. The XRD and TEM analyses revealed high purity and wurtzite hexagonal structure of ZnO NPs with a mean size of 10.01 ± 2.6 nm. Batch experiments were performed to investigate the impact of process parameters viz. Pb(II concentration, pH of solution, adsorbent mass, solution temperature, and contact time variations on the removal efficiency of Pb(II. The adsorption isotherm data provided that the adsorption process was mainly monolayer on ZnO NPs. The adsorption process follows pseudo-second-order reaction kinetic. The maximum removal efficiencies were 93% at pH 5. Thermodynamic parameters such as enthalpy change (ΔH0, free energy change (ΔG0, and entropy change (ΔS0 were calculated; the adsorption process was spontaneous and endothermic. The good efficiency of the as-synthesized NPs makes them attractive for applications in water treatment, for removal of heavy metals from aqueous system.
Munagapati, Venkata Subbaiah; Kim, Dong-Su
2017-07-01
The present study is concerned with the batch adsorption of congo red (CR) from an aqueous solution using calcium alginate beads impregnated with nano-goethite (CABI nano-goethite) as an adsorbent. The optimum conditions for CR removal were determined by studying operational variables viz. pH, adsorbent dose, contact time, initial dye ion concentration and temperature. The CABI nano-goethite was characterized by Fourier transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis. The CR sorption data onto CABI nano-goethite were described using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm model. The maximum adsorption capacity (181.1mg/g) of CR was occurred at pH 3.0. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Desorption experiments were carried out to explore the feasibility of regenerating the adsorbent and the adsorbed CR from CABI nano-goethite. The best desorbing agent was 0.1M NaOH with an efficiency of 94% recovery. The thermodynamic parameters ΔG°, ΔH°, and ΔS° for the CR adsorption were determined by using adsorption capacities at five different temperatures (293, 303, 313, 323 and 303K). Results show that the adsorption process was endothermic and favoured at high temperature. Copyright © 2017 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
A. Parchebaf Jadid
2017-11-01
Full Text Available Edible colors are materials which in the case of adding to food and drinks cause transferring color to them. Most of these colors are not acceptable in terms of applying in human food and underlies various diseases like gastrointestinal disorders, renal, liver and blood toxicity. The goal of this study was investigating the efficiency of improved alumina by sodium dodecyl sulfate (SDS in eliminating Tartrazine from aqueous environments. In this research, the impact of effective parameters such as initial concentration of Tartrazine, time, pH, alumina dose and SDS value were studied in order to approach an optimal condition for eliminating the color. Also, absorption behavior was evaluated by Freundlich and Langmuir isotherms. The highest efficiency of Tartrazine elimination in the solution resulted in optimal pH of 2, the amount of adsorbent 1.5 g/L, 16 min duration and value 0.04 SDS g/l which was obtained for dye concentration 5 mg/L about 94.13%. Also, results suggested that Tartrazine absorption follows Langmuir isotherm (R2 = 0.9867. Obtained results from thermodynamic studies such as Gibbs free energy (-5.728 Kj/mol and enthalpy (-85.86 Kj/mol and entropy (-271.102 J/mol.K also suggested that the absorption process was exothermic. The results of this research suggested that improved alumina by sodium dodecyl sulfate had a relative good capability in Tartrazine elimination from aqueous environments. Thus
International Nuclear Information System (INIS)
Liu, Xiang; Liang, Mengmeng; Hu, Yonghong; Yang, Wenge; Shi, Ying; Yin, Jingjing; Liu, Yan
2014-01-01
Highlights: • The solubility was measured in (water + acetic acid) from 283.15 to 338.15 K. • The solubility increased with increasing temperature and water contents. • The modified Apelblat equation was more accurate than the λh equation. - Abstract: In this study, the solubility of 3-thiophenecarboxylic acid was measured in (water + acetic acid) binary solvent mixtures in the temperature ranging from 283.15 to 338.15 K by the analytical stirred-flask method under atmospheric pressure. The experimental data were well-correlated with the modified Apelblat equation and the λh equation. In addition, the calculated solubilities showed good agreement with the experimental results. It was found that the modified Apelblat equation could obtain the better correlation results than the λh equation. The experiment results indicated that the solubility of 3-thiophenecarboxylic acid in the binary solvents increased with increasing temperature, increases with increasing water contents, but the increments with temperature differed from different water contents. In addition, the thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van’t Hoff analysis. The experimental data and model parameters would be useful for optimizing the process of purification of 3-thiophenecarboxylic acid in industry
International Nuclear Information System (INIS)
Lima da Silva, Aline; De Fraga Malfatti, Celia; Heck, Nestor Cesar
2003-01-01
The use of fuel cells is a promising technology in the conversion of chemical to electrical energy. Due to environmental concerns related to the reduction of atmospheric pollution and greenhouse gases emissions such as CO 2 , NO x and hydrocarbons, there have been many researches about fuel cells using hydrogen as fuel. Hydrogen gas can be produced by several routes; a promising one is the steam reforming of ethanol. This route may become an important industrial process, especially for sugarcane producing countries. Ethanol is renewable energy and presents several advantages over other sources related to natural availability, storage and handling safety. In order to contribute to the understanding of the steam reforming of ethanol inside the reformer, this work displays a detailed thermodynamic analysis of the ethanol/water system, in the temperature range of 500-1200K, considering different H 2 O/ethanol reforming ratios. The equilibrium determinations were done with the help of the Gibbs energy minimization method using the Generalized Reduced Gradient algorithm (GRG). Based on literature data, the species considered in calculations were: H 2 , H 2 O, CO, CO 2 , CH 4 , C 2 H 4 , CH 3 CHO, C 2 H 5 OH (gas phase) and C gr . (graphite phase). The thermodynamic conditions for carbon deposition (probably soot) on catalyst during gas reforming were analyzed, in order to establish temperature ranges and H 2 O/ethanol ratios where carbon precipitation is not thermodynamically feasible. Experimental results from literature show that carbon deposition causes catalyst deactivation during reforming. This deactivation is due to encapsulating carbon that covers active phases on a catalyst substrate, e.g. Ni over Al 2 O 3 . In the present study, a mathematical relationship between Lagrange multipliers and the carbon activity (with reference to the graphite phase) was deduced, unveiling the carbon activity in the reformer atmosphere. From this, it is possible to foreseen if soot
Interfaces at equilibrium: A guide to fundamentals.
Marmur, Abraham
2017-06-01
The fundamentals of the thermodynamics of interfaces are reviewed and concisely presented. The discussion starts with a short review of the elements of bulk thermodynamics that are also relevant to interfaces. It continues with the interfacial thermodynamics of two-phase systems, including the definition of interfacial tension and adsorption. Finally, the interfacial thermodynamics of three-phase (wetting) systems is discussed, including the topic of non-wettable surfaces. A clear distinction is made between equilibrium conditions, in terms of minimizing energies (internal, Gibbs or Helmholtz), and equilibrium indicators, in terms of measurable, intrinsic properties (temperature, chemical potential, pressure). It is emphasized that the equilibrium indicators are the same whatever energy is minimized, if the boundary conditions are properly chosen. Also, to avoid a common confusion, a distinction is made between systems of constant volume and systems with drops of constant volume. Copyright © 2016 Elsevier B.V. All rights reserved.
Garcia-Comas, Maya; Lopez-Puertas, M.; Funke, B.; Bermejo-Pantaleon, D.; Marshall, Benjamin T.; Mertens, Christopher J.; Remsberg, Ellis E.; Mlynczak, Martin G.; Gordley, L. L.; Russell, James M.
2008-01-01
The vast set of near global and continuous atmospheric measurements made by the SABER instrument since 2002, including daytime and nighttime kinetic temperature (T(sub k)) from 20 to 105 km, is available to the scientific community. The temperature is retrieved from SABER measurements of the atmospheric 15 micron CO2 limb emission. This emission separates from local thermodynamic equilibrium (LTE) conditions in the rarefied mesosphere and thermosphere, making it necessary to consider the CO2 vibrational state non-LTE populations in the retrieval algorithm above 70 km. Those populations depend on kinetic parameters describing the rate at which energy exchange between atmospheric molecules take place, but some of these collisional rates are not well known. We consider current uncertainties in the rates of quenching of CO2 (v2 ) by N2 , O2 and O, and the CO2 (v2 ) vibrational-vibrational exchange to estimate their impact on SABER T(sub k) for different atmospheric conditions. The T(sub k) is more sensitive to the uncertainty in the latter two and their effects depend on altitude. The T(sub k) combined systematic error due to non-LTE kinetic parameters does not exceed +/- 1.5 K below 95 km and +/- 4-5 K at 100 km for most latitudes and seasons (except for polar summer) if the Tk profile does not have pronounced vertical structure. The error is +/- 3 K at 80 km, +/- 6 K at 84 km and +/- 18 K at 100 km under the less favourable polar summer conditions. For strong temperature inversion layers, the errors reach +/- 3 K at 82 km and +/- 8 K at 90 km. This particularly affects tide amplitude estimates, with errors of up to +/- 3 K.
Approach to equilibrium in high energy heavy ion collisions
International Nuclear Information System (INIS)
Epelbaum, Thomas
2014-01-01
This thesis deals with the theory of the early stages of a heavy ion collision. Just after such a collision, the matter produced - called the Quark-Gluon-Plasma (QGP) - has been shown to be far out of thermal equilibrium. One would like to know whether the QGP thermalizes, and what is the typical time scale for this. Proving that the QGP thermalizes would also justify from first principles the hydrodynamical treatment of the subsequent evolution of a heavy ion collision. After having recalled some essential theoretical concepts, the manuscript addresses these questions in two different theories. In a first part, we study a scalar field theory. Starting from an out of equilibrium initial condition, one studies the approach to equilibrium in a fixed volume or in a one-dimensional expanding system. In both cases, clear signs of thermalization are obtained: an equation of state is formed, the pressure tensor becomes isotropic and the occupation number approaches a classical thermal distribution. These results are obtained thanks to the classical statistical approximation (CSA), that includes contributions beyond the Leading Order perturbative calculation. In a second part, the Color Glass Condensate - a quantum chromodynamics (QCD) effective theory well suited to describe the early life of the QGP - is used to treat more realistically the approach to thermalization in heavy ion collisions. After having derived some analytical prerequisites for the application of the CSA, the numerical simulations performed with the Yang-Mills equations show evidences of an early onset of hydrodynamical behavior of the QGP: the system becomes isotropic on short time scales, while the shear viscosity over entropy ratio is very small, which is characteristic of a quasi perfect fluid. (author) [fr
Thermodynamics of adaptive molecular resolution.
Delgado-Buscalioni, R
2016-11-13
A relatively general thermodynamic formalism for adaptive molecular resolution (AMR) is presented. The description is based on the approximation of local thermodynamic equilibrium and considers the alchemic parameter λ as the conjugate variable of the potential energy difference between the atomistic and coarse-grained model Φ=U (1) -U (0) The thermodynamic formalism recovers the relations obtained from statistical mechanics of H-AdResS (Español et al, J. Chem. Phys. 142, 064115, 2015 (doi:10.1063/1.4907006)) and provides relations between the free energy compensation and thermodynamic potentials. Inspired by this thermodynamic analogy, several generalizations of AMR are proposed, such as the exploration of new Maxwell relations and how to treat λ and Φ as 'real' thermodynamic variablesThis article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'. © 2016 The Author(s).
Chemical engineering and thermodynamics using Mat lab
International Nuclear Information System (INIS)
Kim Heon; Kim, Moon Gap; Lee, Hak Yeong; Yeo, Yeong Gu; Ham, Seong Won
2002-02-01
This book consists of twelve chapters and four appendixes about chemical engineering and thermodynamics using Mat lab, which deals with introduction, energy budget, entropy, thermodynamics process, generalization on any fluid, engineering equation of state for PVT properties, deviation of the function, phase equilibrium of pure fluid, basic of multicomponent, phase equilibrium of compound by state equation, activity model and reaction system. The appendixes is about summary of computer program, related mathematical formula and material property of pure component.
Thermodynamics of Phantom Energy Accreting onto a Black Hole in Einstein—Power—Maxwell Gravity
International Nuclear Information System (INIS)
Abbas, G.; Ramzan, R. M.
2013-01-01
We investigate the phantom energy accretion onto a 3D black hole formulated in the Einstein—Power—Maxwell theory, and present the conditions for critical accretion of phantom energy onto the black hole. Further, we discuss the thermodynamics of phantom energy accreting onto the black hole and find that the first law of thermodynamics is easily satisfied while the second law and the generalized second law of thermodynamics remain invalid and conditionally valid, respectively. The results for the Banados—Teitelboim—Zanelli black hole can be recovered by taking Maxwellian contribution equal to zero
Brignole, Esteban Alberto
2013-01-01
Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and
Thermodynamic properties and energy characteristics of water+1-propanol
Alhasov, A. B.; Bazaev, A. R.; Bazaev, E. A.; Osmanova, B. K.
2017-11-01
By using own precise experimental data on p,ρ,T,x- relations differential and integral thermodynamic properties of water+1-propanol homogeneous binary mixtures (0.2, 0.5, and 0.8 mole fractions of 1-propanol) were obtained in one phase (liquid, vapor) region, along coexistence curve phase, at critical and supercritical regions of parameters of state. These values were obtained in the regions of temperatures 373.15 - 673.15 K, densities 3 - 820 kg/m3 and pressures up to 50 MPa. It is found that shape of p,ρ,T,- dependences of water+1-propanol mixtures in investigated range of temperatures is the same with those of pure liquid, but the pressure of the mixture is higher than those of pure water or 1-propanol. The critical line of water+1-propanol binary mixtures as opposed to those of water+methanol and water+ethanol mixtures has convex shape. It is ascertained that using water+1-propanol mixture (0.2 mol.fraction of 1-propanol) instead of pure water allows to decrease lower limit of operating temperatures to 50 K, to increase effective coefficient of efficiency and partially unify thermal mechanical equipment of power plant. Our comparative energy analysis of cycles of steam-turbine plant on water and water+1- propanol mixtures, carried out at the same thermobaric conditionsand showed that thermal coefficient of efficiencyofcycle of steam-turbine plant onwater+1-propanol mixture (0.2 mol.fraction of 1-propanol) is higher than those of pure water.Thus and so we made a conclusion about usability of water+1-propanol mixture (0.2 mole fraction of 1-propanol) as a working substance of steam-turbine plant cycle.
Description of quantum coherence in thermodynamic processes requires constraints beyond free energy
Lostaglio, Matteo; Jennings, David; Rudolph, Terry
2015-01-01
Recent studies have developed fundamental limitations on nanoscale thermodynamics, in terms of a set of independent free energy relations. Here we show that free energy relations cannot properly describe quantum coherence in thermodynamic processes. By casting time-asymmetry as a quantifiable, fundamental resource of a quantum state, we arrive at an additional, independent set of thermodynamic constraints that naturally extend the existing ones. These asymmetry relations reveal that the traditional Szilárd engine argument does not extend automatically to quantum coherences, but instead only relational coherences in a multipartite scenario can contribute to thermodynamic work. We find that coherence transformations are always irreversible. Our results also reveal additional structural parallels between thermodynamics and the theory of entanglement. PMID:25754774
Description of quantum coherence in thermodynamic processes requires constraints beyond free energy
Lostaglio, Matteo; Jennings, David; Rudolph, Terry
2015-03-01
Recent studies have developed fundamental limitations on nanoscale thermodynamics, in terms of a set of independent free energy relations. Here we show that free energy relations cannot properly describe quantum coherence in thermodynamic processes. By casting time-asymmetry as a quantifiable, fundamental resource of a quantum state, we arrive at an additional, independent set of thermodynamic constraints that naturally extend the existing ones. These asymmetry relations reveal that the traditional Szilárd engine argument does not extend automatically to quantum coherences, but instead only relational coherences in a multipartite scenario can contribute to thermodynamic work. We find that coherence transformations are always irreversible. Our results also reveal additional structural parallels between thermodynamics and the theory of entanglement.
Thermodynamic estimation: Ionic materials
International Nuclear Information System (INIS)
Glasser, Leslie
2013-01-01
Thermodynamics establishes equilibrium relations among thermodynamic parameters (“properties”) and delineates the effects of variation of the thermodynamic functions (typically temperature and pressure) on those parameters. However, classical thermodynamics does not provide values for the necessary thermodynamic properties, which must be established by extra-thermodynamic means such as experiment, theoretical calculation, or empirical estimation. While many values may be found in the numerous collected tables in the literature, these are necessarily incomplete because either the experimental measurements have not been made or the materials may be hypothetical. The current paper presents a number of simple and relible estimation methods for thermodynamic properties, principally for ionic materials. The results may also be used as a check for obvious errors in published values. The estimation methods described are typically based on addition of properties of individual ions, or sums of properties of neutral ion groups (such as “double” salts, in the Simple Salt Approximation), or based upon correlations such as with formula unit volumes (Volume-Based Thermodynamics). - Graphical abstract: Thermodynamic properties of ionic materials may be readily estimated by summation of the properties of individual ions, by summation of the properties of ‘double salts’, and by correlation with formula volume. Such estimates may fill gaps in the literature, and may also be used as checks of published values. This simplicity arises from exploitation of the fact that repulsive energy terms are of short range and very similar across materials, while coulombic interactions provide a very large component of the attractive energy in ionic systems. Display Omitted - Highlights: • Estimation methods for thermodynamic properties of ionic materials are introduced. • Methods are based on summation of single ions, multiple salts, and correlations. • Heat capacity, entropy
Replacing leads by self-energies using non-equilibrium Green's functions
International Nuclear Information System (INIS)
Michael, Fredrick; Johnson, M.D.
2003-01-01
Open quantum systems consist of semi-infinite leads which transport electrons to and from the device of interest. We show here that within the non-equilibrium Green's function technique for continuum systems, the leads can be replaced by simple c-number self-energies. Our starting point is an approach for continuum systems developed by Feuchtwang. The reformulation developed here is simpler to understand and carry out than the somewhat unwieldly manipulations typical in the Feuchtwang method. The self-energies turn out to have a limited variability: the retarded self-energy Σ r depends on the arbitrary choice of internal boundary conditions, but the non-equilibrium self-energy or scattering function Σ which determines transport is invariant for a broad class of boundary conditions. Expressed in terms of these self-energies, continuum non-equilibrium transport calculations take a particularly simple form similar to that developed for discrete systems
A study in cosmology and causal thermodynamics
International Nuclear Information System (INIS)
Oliveira, H.P. de.
1986-01-01
The especial relativity of thermodynamic theories for reversible and irreversible processes in continuous medium is studied. The formalism referring to equilibrium and non-equilibrium configurations, and theories which includes the presence of gravitational fields are discussed. The nebular model in contraction with dissipative processes identified by heat flux and volumetric viscosity is thermodymically analysed. This model is presented by a plane conformal metric. The temperature, pressure, entropy and entropy production within thermodynamic formalism which adopts the hypothesis of local equilibrium, is calculated. The same analysis is carried out considering a causal thermodynamics, which establishes a local entropy of non-equilibrium. Possible homogeneous and isotropic cosmological models, considering the new phenomenological equation for volumetric viscosity deriving from cause thermodynamics are investigated. The found out models have plane spatial section (K=0) and some ones do not have singularities. The energy conditions are verified and the entropy production for physically reasobable models are calculated. (M.C.K.) [pt
International Nuclear Information System (INIS)
Zhang, Xiao; Wang, Haifeng; Kuang, Wangwang; Zhang, Jianbao
2017-01-01
Modeling of non-equilibrium solidification in multi-component alloys is of singular importance in microstructure control, which however owing to the complex systems with complex additional constraints is still an open problem. In this work, the thermodynamic extremal principle was applied to solve the complex additional constraints self-consistently in thermodynamics. Consequently, short-range solute redistribution and long-range solute diffusion that share the same mobility are integrated naturally into the solute diffusion equations, thus avoiding the introduction of additional kinetic coefficients (e.g. interface permeability) to describe solute redistribution. Application to the non-equilibrium solidification of Al-Si-Cu alloys shows that anomalous solute trapping and anomalous solute profiles within the diffuse interface could occur, thus highlighting the important effect of the interaction among the component elements on the interface kinetics. The current phase-field model might be preferred for simulations not only because of its simplest form of evolution equations but also its feasibility to increase the simulation efficiency by the “thin interface limit” analysis.
Bounded energy exchange as an alternative to the third law of thermodynamics
Energy Technology Data Exchange (ETDEWEB)
Heidrich, Matthias, E-mail: Heidrich_Matthias@web.de
2016-10-15
This paper introduces a postulate explicitly forbidding the extraction of an infinite amount of energy from a thermodynamic system. It also introduces the assumption that no measuring equipment is capable of detecting arbitrarily small energy exchanges. The Kelvin formulation of the second law is reinterpreted accordingly. Then statements related to both the unattainability version and the entropic version of the third law are derived. The value of any common thermodynamic potential of a one-component system at absolute zero of temperature is ascertained if some assumptions with regard to the state space can be made. The point of view is the phenomenological, macroscopic and non-statistical one of classical thermodynamics.
Bounded energy exchange as an alternative to the third law of thermodynamics
International Nuclear Information System (INIS)
Heidrich, Matthias
2016-01-01
This paper introduces a postulate explicitly forbidding the extraction of an infinite amount of energy from a thermodynamic system. It also introduces the assumption that no measuring equipment is capable of detecting arbitrarily small energy exchanges. The Kelvin formulation of the second law is reinterpreted accordingly. Then statements related to both the unattainability version and the entropic version of the third law are derived. The value of any common thermodynamic potential of a one-component system at absolute zero of temperature is ascertained if some assumptions with regard to the state space can be made. The point of view is the phenomenological, macroscopic and non-statistical one of classical thermodynamics.
International Nuclear Information System (INIS)
Moog, H.C.; Keesmann, S.M.
2007-02-01
This paper reports on the project ''Coupling transport models with thermodynamic equilibrium calculations'' - short title EQLINK, promotion code number 02 E 9723 - in the which the scope for coupling thermodynamic equilibrium model calculations with EMOS was expanded and improved. The first step was to inquire into the current state of research on radiolytic processes. It transpired that there is currently no conclusive description of radiolytic processes. The existing descriptions are too complex and too narrowly geared to specific scenarios to allow a general view on radiolytic processes, which would be a prerequisite for creating suitable long-term geochemical safety analysis modules. It appears that the approximation calculations implemented in EMOS tend to overestimate rather than underestimate radiolytic gas formation. The thermodynamic database which is used at GRS (Society for Plant and Reactor Safety) as a basis for coupled transport calculations has been updated. For this purpose the radionuclide database of the Institut fuer Nukleare Entsorgung (INE = Institute for Nuclear Disposal) was converted to an in-house format which permits creating parameter files for specific requirements. The data of the INE comprise thermodynamic parameters such as equilibrium constants, Gibbs free enthalpies of formation, enthalpies and entropies of formation and Pitzer parameters, which are required for model calculations on high-saline solutions. The database for low-saline solutions which had been developed by PSI/NAGRA for calculations with CLAYPOS was also adopted. Both parameter sets were subjected to test calculations to detect any errors that might have occurred during the data transfer. It is thus now possible to perform coupled transport calculations with the EMOS modules LOPOS and CLAYPOS according to the state of the art of geochemical research. The EQLINK interface which had been developed in an earlier project, titled ''Development of a model for describing the
Energy systems a new approach to engineering thermodynamics
Gicquel, Renaud
2011-01-01
Forewords, About the Author, General introduction, Structure of the book, Objectives, A working tool on many levels, Mind Maps, List of Symbols, Conversion FactorsI First Steps in Engineering Thermodynamics1 A New Educational Paradigm1.1 Introduction1.2 General remarks on the evolution of training specifi cations1.3 Specifi cs of applied thermodynamics teaching1.4 A new educational paradigm1.5 Diapason modules1.6 A three-step progressive approach1.7 Main pedagogic innovations brought by Thermoptim1.8 Digital resources of the Thermoptim-UNIT portal1.9 Comparison with other tools with teaching p
Is applicable thermodynamics of negative temperature for living organisms?
Atanasov, Atanas Todorov
2017-11-01
During organismal development the moment of sexual maturity can be characterizes by nearly maximum basal metabolic rate and body mass. Once the living organism reaches extreme values of the mass and the basal metabolic rate, it reaches near equilibrium thermodynamic steady state physiological level with maximum organismal complexity. Such thermodynamic systems that reach equilibrium steady state level at maximum mass-energy characteristics can be regarded from the prospective of thermodynamics of negative temperature. In these systems the increase of the internal and free energy is accompanied with decrease of the entropy. In our study we show the possibility the living organisms to regard as thermodynamic system with negative temperature
M. M. Clark; T. H. Fletcher; R. R. Linn
2010-01-01
The chemical processes of gas phase combustion in wildland fires are complex and occur at length-scales that are not resolved in computational fluid dynamics (CFD) models of landscape-scale wildland fire. A new approach for modelling fire chemistry in HIGRAD/FIRETEC (a landscape-scale CFD wildfire model) applies a mixtureâ fraction model relying on thermodynamic...
Non-equilibrium supramolecular polymerization.
Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M
2017-09-18
Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.
International Nuclear Information System (INIS)
Wu, Y.J.; Rosen, M.A.
1999-01-01
Energy equilibrium models can be valuable aids in energy planning and decision-making. In such models, supply is represented by a cost-minimizing linear submodel and demand by a smooth vector-valued function of prices. In this paper, we use the energy equilibrium model to study conventional systems and cogeneration-based district energy (DE) systems for providing heating, cooling and electrical services, not only to assess the potential economic and environmental benefits of cogeneration-based DE systems, but also to develop optimal configurations while accounting for such factors as economics and environmental impact. The energy equilibrium model is formulated and solved with software called WATEMS, which uses sequential non-linear programming to calculate the intertemporal equilibrium of energy supplies and demands. The methods of analysis and evaluation for the economic and environmental impacts are carefully explored. An illustrative energy equilibrium model of conventional and cogeneration-based DE systems is developed within WATEMS to compare quantitatively the economic and environmental impacts of those systems for various scenarios. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)
International Nuclear Information System (INIS)
Mansson, B.A.
1990-01-01
Economics, as the social science most concerned with the use and distribution of natural resources, must start to make use of the knowledge at hand in the natural sciences about such resources. In this, thermodynamics is an essential part. In a physicists terminology, human economic activity may be described as a dissipative system which flourishes by transforming and exchanging resources, goods and services. All this involves complex networks of flows of energy and materials. This implies that thermodynamics, the physical theory of energy and materials flows, must have implications for economics. On another level, thermodynamics has been recognized as a physical theory of value, with value concepts similar to those of economic theory. This paper discusses some general aspects of the significance of non-equilibrium thermodynamics for economics. The role of exergy, probably the most important of the physical measures of value, is elucidated. Two examples of integration of thermodynamics with economic theory are reviewed. First, a simple model of a steady-state production system is sued to illustrate the effects of thermodynamic process constraints. Second, the framework of a simple macroeconomic growth model is used to illustrate how some thermodynamic limitations may be integrated in macroeconomic theory
Directory of Open Access Journals (Sweden)
Chellaboina Vijaysekhar
2005-01-01
Full Text Available We develop thermodynamic models for discrete-time large-scale dynamical systems. Specifically, using compartmental dynamical system theory, we develop energy flow models possessing energy conservation, energy equipartition, temperature equipartition, and entropy nonconservation principles for discrete-time, large-scale dynamical systems. Furthermore, we introduce a new and dual notion to entropy; namely, ectropy, as a measure of the tendency of a dynamical system to do useful work and grow more organized, and show that conservation of energy in an isolated thermodynamic system necessarily leads to nonconservation of ectropy and entropy. In addition, using the system ectropy as a Lyapunov function candidate, we show that our discrete-time, large-scale thermodynamic energy flow model has convergent trajectories to Lyapunov stable equilibria determined by the system initial subsystem energies.
Energy and transverse momentum fluctuations in the equilibrium quantum systems
International Nuclear Information System (INIS)
Gorenstein, M.I.; Rybczyński, M.
2014-01-01
The fluctuations in the ideal quantum gases are studied using the strongly intensive measures Δ[A,B] and Σ[A,B] defined in terms of two extensive quantities A and B. In the present Letter, these extensive quantities are taken as the motional variable, A=X, the system energy E or transverse momentum P T , and number of particles, B=N. This choice is most often considered in studying the event-by-event fluctuations and correlations in high energy nucleus–nucleus collisions. The recently proposed special normalization ensures that Δ and Σ are dimensionless and equal to unity for fluctuations given by the independent particle model. In statistical mechanics, the grand canonical ensemble formulation within the Boltzmann approximation gives an example of independent particle model. Our results demonstrate the effects due to the Bose and Fermi statistics. Estimates of the effects of quantum statistics in the hadron gas at temperatures and chemical potentials typical for thermal models of hadron production in high energy collisions are presented. In the case of massless particles and zero chemical potential the Δ and Σ measures are calculated analytically/
Thermodynamics in Loop Quantum Cosmology
International Nuclear Information System (INIS)
Li, L.F.; Zhu, J.Y.
2009-01-01
Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. Moreover, the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but also are actually found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.
Smirnyagina, N. N.; Khaltanova, V. M.; Lapina, A. E.; Dasheev, D. E.
2017-01-01
Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VT-1 are generated at diffused saturation in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.
Out-of-equilibrium phenomena in high energy nuclear collisions
Serreau, J
2001-01-01
In the first part we study the possibility that a Disoriented Chiral Condensate (DCC) forms when hot hadronic matter is quenched, using the linear sigma model. We formulate an original sampling strategy for the initial field configuration in order to get an estimate of the probability that a potentially observable coherent pion field appears in a heavy-ion collision. We obtain a probability of the order of 1/1000 at CERN SPS energies. Next, we study the correlation between isospin orientations of the distinct modes of the pion field emerging after a quench. We show that this correlation is absent: the distinct modes behave as distinct DCCs. This contradicts the common belief that the state produced in the simplest form of the quench scenario - with a fully thermalized initial state - is identical to the originally proposed DCC. In the second part, we investigate the role of elastic scatterings in the process of kinetic equilibration of gluons produced in the very early times of the collision. We compare the t...
International Nuclear Information System (INIS)
Karamoddin, Maryam; Varaminian, Farshad
2013-01-01
Highlights: • Three-phase equilibrium data, (VL W H), were measured for HCFC22 and HFC134a hydrates. • The pressures were evaluated by simple EoSs (modified mixing rule) and CPA EOS. • The Kihara potential parameters were obtained by optimizing scheme for refrigerants. -- Abstract: In this study, three-phase equilibrium conditions of hydrate-liquid–vapor, (VL W H), were experimentally determined for chlorodifluoromethane and 1,1,1,2-tetrafluoroethane gas hydrates at temperatures ranging from (278 to 290) K and (280 to 285) K respectively, at pressures ranging from (0.2 to 0.8) MPa. Then the different models were presented for estimating of the hydrate dissociation conditions of chlorodifluoromethane, 1,1,1,2-tetrafluoroethane and 1,1-difluoroethane refrigerants. The cubic simple equations of state (SRK and VPT) and the cubic plus association equation of state (CPA) were employed for modeling the vapor and liquid phases, also van der Waals–Platteeuw statistical model was used for the solid hydrate phase. In this paper, the binary interaction parameters of classic and modified mixing rules were optimized by using two-phase equilibrium data (VL W H). The Kihara potential parameters in each refrigerant were estimated using obtained experimental equilibrium data (VL W H) and based on the optimization scheme by the Nelder Mead optimization method. The agreement between the experimental and the predicted pressure is acceptable by using these models. The average deviation of models for chlorodifluoromethane, 1,1,1,2-tetrafluoroethane, and 1,1-difluoroethane hydrates is about 3%, 4.3%, and 3.6%, respectively
Thermodynamic and Quantum Thermodynamic Analyses of Brownian Movement
Gyftopoulos, Elias P.
2006-01-01
Thermodynamic and quantum thermodynamic analyses of Brownian movement of a solvent and a colloid passing through neutral thermodynamic equilibrium states only. It is shown that Brownian motors and E. coli do not represent Brownian movement.
Energy Technology Data Exchange (ETDEWEB)
Seker, Ayseguel [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: aysegulseker@iyte.edu.tr; Shahwan, Talal [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: talalshahwan@iyte.edu.tr; Eroglu, Ahmet E. [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: ahmeteroglu@iyte.edu.tr; Yilmaz, Sinan [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: sinanyilmaz@iyte.edu.tr; Demirel, Zeliha [Department of Biology, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: zelihademirel@gmail.com; Dalay, Meltem Conk [Department of Bioengineering, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: meltemconkdalay@gmail.com
2008-06-15
The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as {delta}G{sup o}, {delta}H{sup o}and {delta}S{sup o} calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb{sup 2+} ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.
A strictly hyperbolic equilibrium phase transition model
International Nuclear Information System (INIS)
Allaire, G; Faccanoni, G; Kokh, S.
2007-01-01
This Note is concerned with the strict hyperbolicity of the compressible Euler equations equipped with an equation of state that describes the thermodynamical equilibrium between the liquid phase and the vapor phase of a fluid. The proof is valid for a very wide class of fluids. The argument only relies on smoothness assumptions and on the classical thermodynamical stability assumptions, that requires a definite negative Hessian matrix for each phase entropy as a function of the specific volume and internal energy. (authors)
Thermodynamic investigation of fluoride salts for nuclear energy production
International Nuclear Information System (INIS)
Beilmann, Markus
2013-01-01
In this work thermodynamic properties of molten fluoride salts and salt mixtures are investigated. Fluoride salts have advantageous properties to be used in energy producing systems based on the conversion from heat to energy like i.e in Molten Salt Reactors. For this purpose it is very important to have detailed information about the heat capacity of the pure salts and salt mixtures. To get a better understanding about the heat capacity in mixtures drop calorimetry measurements of mixtures of LiF with other alkali fluorides were conducted and compared. The investigation of fluoride salts at elevated temperatures is complicated by the fact that fluoride vapour is aggressive to many materials. In order to protect our sensitive measurement equipment the salt samples were encapsulated in nickel crucibles using a laser welding technique and afterwards the whole nickel capsule was measured. This method was verified by the measurement of unmixed CsF and KF where in both examples an excellent agreement with literature data was obtained. Afterwards various intermediate compositions of the systems LiF-KF, LiF-CsF and LiF-RbF were investigated and a general trend according to the difference in cation radii could be established. In combination with literature data for the LiF-NaF system the heat capacity of the liquid state follows the order LiF-NaF 2 -LaF 3 phase diagram was obtained. With the help of mathematical models the phase diagrams can be calculated and also higher order systems can be predicted. The LiF-NaF-CaF 2 -LaF 3 system was calculated with the classical polynomial model and the quasi-chemical model in parallel in order to evaluate which of the two models provide a better extrapolation to higher order systems (ternary or quaternary) based on the related binary systems. The two models behaved very similar at the investigated system and the quasi-chemical model was chosen for further assessments of phase diagrams. This model was selected, since it considers the
Vargas, Francisco M.
2014-01-01
The temperature dependence of the Gibbs energy and important quantities such as Henry's law constants, activity coefficients, and chemical equilibrium constants is usually calculated by using the Gibbs-Helmholtz equation. Although, this is a well-known approach and traditionally covered as part of any physical chemistry course, the required…
How energy conversion drives economic growth far from the equilibrium of neoclassical economics
International Nuclear Information System (INIS)
Kümmel, Reiner; Lindenberger, Dietmar
2014-01-01
Energy conversion in the machines and information processors of the capital stock drives the growth of modern economies. This is exemplified for Germany, Japan, and the USA during the second half of the 20th century: econometric analyses reveal that the output elasticity, i.e. the economic weight, of energy is much larger than energy's share in total factor cost, while for labor just the opposite is true. This is at variance with mainstream economic theory according to which an economy should operate in the neoclassical equilibrium, where output elasticities equal factor cost shares. The standard derivation of the neoclassical equilibrium from the maximization of profit or of time-integrated utility disregards technological constraints. We show that the inclusion of these constraints in our nonlinear-optimization calculus results in equilibrium conditions, where generalized shadow prices destroy the equality of output elasticities and cost shares. Consequently, at the prices of capital, labor, and energy we have known so far, industrial economies have evolved far from the neoclassical equilibrium. This is illustrated by the example of the German industrial sector evolving on the mountain of factor costs before and during the first and the second oil price explosion. It indicates the influence of the ‘virtually binding’ technological constraints on entrepreneurial decisions, and the existence of ‘soft constraints’ as well. Implications for employment and future economic growth are discussed. (paper)
Effects of energy conservation on equilibrium properties of hot asymmetric nuclear matter
Zhang, Zhen; Ko, Che Ming
2018-01-01
Based on the relativistic Vlasov-Uehling-Uhlenbeck transport model, which includes relativistic scalar and vector potentials on baryons, we consider an N -Δ -π system in a box with periodic boundary conditions to study the effects of energy conservation in particle production and absorption processes on the equilibrium properties of the system. The density and temperature of the matter in the box are taken to be similar to the hot dense matter formed in heavy ion collisions at intermediate energies. We find that to maintain the equilibrium numbers of N ,Δ , and π , which depend on the mean-field potentials of N and Δ , we must include these potentials in the energy conservation condition that determines the momenta of outgoing particles after a scattering or decay process. We further find that the baryon scalar potentials mainly affect the Δ and pion equilibrium numbers, while the baryon vector potentials have considerable effect on the effective charged pion ratio at equilibrium. Our results thus indicate that it is essential to include in the transport model the effect of potentials in the energy conservation of a scattering or decay process, which is ignored in most transport models, for studying pion production in heavy ion collisions.
How energy conversion drives economic growth far from the equilibrium of neoclassical economics
Kümmel, Reiner; Lindenberger, Dietmar
2014-12-01
Energy conversion in the machines and information processors of the capital stock drives the growth of modern economies. This is exemplified for Germany, Japan, and the USA during the second half of the 20th century: econometric analyses reveal that the output elasticity, i.e. the economic weight, of energy is much larger than energy's share in total factor cost, while for labor just the opposite is true. This is at variance with mainstream economic theory according to which an economy should operate in the neoclassical equilibrium, where output elasticities equal factor cost shares. The standard derivation of the neoclassical equilibrium from the maximization of profit or of time-integrated utility disregards technological constraints. We show that the inclusion of these constraints in our nonlinear-optimization calculus results in equilibrium conditions, where generalized shadow prices destroy the equality of output elasticities and cost shares. Consequently, at the prices of capital, labor, and energy we have known so far, industrial economies have evolved far from the neoclassical equilibrium. This is illustrated by the example of the German industrial sector evolving on the mountain of factor costs before and during the first and the second oil price explosion. It indicates the influence of the ‘virtually binding’ technological constraints on entrepreneurial decisions, and the existence of ‘soft constraints’ as well. Implications for employment and future economic growth are discussed.
Thermodynamics of Radiation Modes
Pina, Eduardo; de la Selva, Sara Maria Teresa
2010-01-01
We study the equilibrium thermodynamics of the electromagnetic radiation in a cavity of a given volume and temperature. We found three levels of description, the thermodynamics of one mode, the thermodynamics of the distribution of frequencies in a band by summing over the frequencies in it and the global thermodynamics by summing over all the…
Directory of Open Access Journals (Sweden)
Ruth Alfaro-Cuevas-Villanueva
2014-01-01
Full Text Available The sorption of cadmium (Cd and lead (Pb by calcium alginate beads (CAB from aqueous solutions in batch systems was investigated. The kinetic and thermodynamic parameters, as well as the sorption capacities of CAB in each system at different temperatures, were evaluated. The rate of sorption for both metals was rapid in the first 10 minutes and reached a maximum in 50 minutes. Sorption kinetic data were fitted to Lagergren, pseudo-second-order and Elovich models and it was found that the second-order kinetic model describes these data for the two metals; comparing kinetic parameters for Cd and Pb sorption a higher kinetic rate (K2 for Pb was observed, indicating that the interaction between lead cations and alginate beads was faster than for cadmium. Similarly, isotherm data were fitted to different models reported in literature and it was found that the Langmuir-Freundlich (L-F and Dubinin-Radushkevich (D-R models describe the isotherms in all cases. CAB sorption capacity for cadmium was 27.4 mg/g and 150.4 mg/g for lead, at 25°C. Sorption capacities of Cd and Pb increase as temperature rises. According to the thermodynamic parameters, the cadmium and lead adsorption process was spontaneous and endothermic. It was also found that pH has an important effect on the adsorption of these metals by CAB, as more were removed at pH values between 6 and 7.
Yip, N.Y.; Vermaas, D.A.; Nijmeijer, K.; Elimelech, M.
2014-01-01
Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we
Integration of ecological and thermodynamic concepts in the design of sustainable energy landscapes
Stremke, S.; Koh, J.
2011-01-01
Resource depletion and climate change motivate a transition to sustainable energy systems that make effective use of renewable sources. Whereas nature presents strategies to sustain on the basis of renewables, the Laws of Thermodynamics can help to increase efficiency in energy use. In previous
Kojitani, Hiroshi; Yamazaki, Monami; Kojima, Meiko; Inaguma, Yoshiyuki; Mori, Daisuke; Akaogi, Masaki
2018-06-01
Heat capacity (C P) of rutile and α-PbO2 type TiO2 (TiO2-II) were measured by the differential scanning calorimetry and thermal relaxation method. Using the results, standard entropies at 1 atm and 298.15 K of rutile and TiO2-II were determined to be 50.04(4) and 46.54(2) J/mol K, respectively. Furthermore, thermal expansivity (α) determined by high-temperature X-ray diffraction measurement and mode Grüneisen parameters obtained by high-pressure Raman spectroscopy suggested the thermal Grüneisen parameter (γ th) for TiO2-II of 1.7(1). By applying the obtained low-temperature C P and γ th, the measured C P and α data of TiO2-II were extrapolated to higher temperature region using a lattice vibrational model calculation, as well as rutile. Internally consistent thermodynamic data sets of both rutile and TiO2-II assessed in this study were used to thermodynamically calculate the rutile‒TiO2-II phase equilibrium boundary. The most plausible boundary was obtained to be P (GPa) = 0.0074T (K) - 1.7. Our boundary suggests that the crystal growth of TiO2-II observed below 5.5 GPa and 900 K in previous studies advanced in its stability field. The phase boundary calculation also suggested small, exothermic phase transition enthalpy from rutile to TiO2-II at 1 atm and 298.15 K of - 0.5 to - 1.1 kJ/mol. This implies that the thermodynamic stability of rutile at 1 atm above room temperature is due to larger contribution of entropy term.
Energy Technology Data Exchange (ETDEWEB)
Shaker, Medhat A., E-mail: drmashaker@yahoo.com [Current address: Chemistry Department, Faculty of Science, University of Jeddah, Jeddah (Saudi Arabia); Permanent address: Chemistry Department, Faculty of Science, Damanhour University, Damanhour (Egypt)
2015-07-15
Ternary nanoparticles of chitosan, non-viable biomass (Pseudomonas sp.) and gelatin, CPG were synthesized by chemical crosslinking method and applied as a novel and cost-effective solid phase to adsorb Pb(II) cations from aqueous solution. Characterization of the fabricated CPG nanoparticles and their complexation behavior were extensively interrogated by dynamic light scattering (DLS), FTIR, TGA, XRD and SEM techniques. The extent of adsorption was found to be a function of medium pH, contact time, initial Pb(II) concentration and temperature. The Langmuir, Freundlich, Dubinin–Radushkevich and Redlich–Peterson models were used to illustrate the isotherms of the adsorption system. The adsorption of Pb(II) cations onto CPG best-fits the Langmuir isotherm model which predicts two stoichiometric temperature-independent adsorption sites, A and B with variable capacities, 35.4 and 91.1 mg g{sup −1}, respectively and removal capacity above 90%. Thermodynamic studies revealed that the adsorption process was physical, spontaneous, and endothermic. The adsorption rate is influenced by temperature and the adsorption kinetic is well confirmed with pseudo-second-order equation compared with three other investigated kinetic models. Present study indicated potential applications of CPG nanoparticles as excellent natural and promising solid phase for Pb(II) extraction in wastewater treatment. - Graphical abstract: Display Omitted - Highlights: • Kinetics and thermodynamics of Pb{sup 2+} biosorption onto CPG nanoparticles are studied. • Adsorption kinetic data are best modeled using second-order rate equations. • The Pb{sup 2}adsorption onto CPG was physical diffusion controlled reaction. • The experimental equilibrium results well fit the Langmuir model. • The thermodynamics show endothermic, favorable and spontaneous adsorption processes.
McKenna, Russell
2009-01-01
Overreliance on energy from fossil fuels is unsustainable because of their regional depletion and associated environmental impacts. The British industrial sector accounts for around one fifth of final energy demand and one third of carbon emissions nationally. This thesis attempts to quantify the potential for industrial energy efficiency from the current baseline, by adopting thermodynamic and economic perspectives. The methodology involves a top-down analysis of energy trends within the man...
DEFF Research Database (Denmark)
Hosokawa, Yoshifumi; Yamada, Kazuo; Johannesson, Björn
2011-01-01
different types of cements. For example, the physicochemical evaluation of steel corrosion initiation can be studied by calculating the molar ratio of chloride ion to hydroxide ion in the pore solution. The model can, further, for example, calculate changes of solid-phase composition caused......) theory alone, not involving chemical processes, have no real practical interest since the chemical action is very dominant for cement based materials. Coupled mass transport and chemical equilibrium models can be used to calculate the variation in pore solution and solid-phase composition when using...
Oil Subsidies and Renewable Energy in Saudi Arabia: A General Equilibrium Approach
Blazquez, J; Hunt, Lester; Manzano, B
2017-01-01
In 2016, the Kingdom of Saudi Arabia (KSA) announced its Vision 2030 strategic plan incorporating major changes to the economic structure of the country, including an intention to deploy 9.5 GW of renewable energy in an effort to reduce the penetration of oil in the electricity generation system. This paper assesses the macroeconomic impact of such changes in the KSA, coupled with reductions in implicit energy subsidies. Based on a dynamic general equilibrium model, our analysis suggests that...
International Nuclear Information System (INIS)
Koalaga, Zacharie
2002-01-01
The purpose of this paper is to study the influence of the choice of internal temperatures on the composition of C x H y O z N t plasmas out of thermodynamic equilibrium. The numerical calculation is specially performed for CH 2 plasma in the pressure range 0.1-1 MPa and for the electron temperature range 5000-30 000 K. Precisely, the investigation of this plasma allows one to show that the choice of internal temperatures can have more influence on plasma composition than the choice of the form of the two-temperature Saha and Guldberg-Waage laws. Indeed, for one of the supposed hypotheses, it is observed that the two forms of the two-temperature system used here can give the same equilibrium composition by uncoupling the excitation temperature of the diatomic and the monatomic species. Great attention must then be given to the adopted hypothesis for internal temperature and not only to the form of the two temperature system used. An accurate comparison between the two models requires the measurement of plasma parameters such as the various internal temperatures and the species concentration. Therefore, we have also carried out an analysis of the potential experimental diagnostics of these plasma parameters. Such diagnostics can help to test and validate theoretical models
International Nuclear Information System (INIS)
Lataye, D.H.; Mishra, I.M.; Mall, I.D.
2008-01-01
The present study deals with the adsorption of pyridine (Py) from synthetic aqueous solutions by rice husk ash (RHA) and commercial grade granular activated carbon (GAC) and reports on the kinetic, equilibrium and thermodynamic aspects of Py sorption. Batch sorption studies were carried out to evaluate the effect of various parameters, such as adsorbent dose (m), initial pH (pH 0 ), contact time (t), initial concentration (C 0 ) and temperature (T) on the removal of Py. The maximum removal of Py is found to be ∼96% and ∼97% at lower concentrations ( -3 ) and ∼79.5% and ∼84% at higher concentrations (600 mg dm -3 ) using 50 kg m -3 and 30 kg m -3 of RHA and GAC dosage, respectively, at 30 ± 1 o C. Adsorption of Py is found to be endothermic in nature and the equilibrium data can be adequately represented by Toth and Redlich-Peterson isotherm equations. Py can be recovered from the spent adsorbents by using acidic water and 0.1 N H 2 SO 4 . The overall adsorption of Py on RHA and GAC is found to be in the order of GAC > RHA. Comparative assessment of adsorbents used by various investigators available in literature showed the effectiveness of BFA and RHA over other adsorbents. Spent RHA can simply be filtered, dried and used in the boiler furnaces/incinerators. Thus, its heating value can be recovered
Energy Technology Data Exchange (ETDEWEB)
Gorzin, Fatemeh; Ghoreyshi, Ali Asghar [Babol University of Technology, Babol (Iran, Islamic Republic of)
2013-08-15
Elimination of Cr (Ⅵ) from aqueous solution was investigated by a new low cost activated carbon developed from aerobically digested activated sludge (ADAS). The adsorbent demonstrated remarkable characteristics such as high surface area of 760m{sup 2}·g{sup −1} and large total pore volume of 0.8383 cm{sup 3}·g{sup −1}. The maximum equilibrium uptake of Cr (Ⅵ) was 70.15 mg·g{sup −1} at optimum pH 2.0. Interpretation of equilibrium data revealed that the best description was provided by the Freundlich isotherm. The kinetics of Cr (Ⅵ) adsorption was well described by the pseudo-second order equation. Calculation of thermodynamic parameters revealed that the adsorption process was endothermic, spontaneous and feasible.. The adsorbent was regenerated using NaOH and it was found to be suitable for reuse in successive adsorption-desorption cycles. The desorption efficiency of Cr (Ⅵ) ion was up to 78%. Finally, comparison of Cr (Ⅵ) adsorption capacity of the developed adsorbent with commercial activated carbon demonstrated its higher performance.
International Nuclear Information System (INIS)
Li, Tao; Deng, Renlun; Wu, Gang; Gu, Pengfei; Hu, Yonghong; Yang, Wenge; Yu, Yemin; Zhang, Yuhao; Yang, Chen
2017-01-01
Highlights: • The solubility increased with increasing temperature. • Data were fitted using the modified Apelblat equation and other models in pure solvents. • Data were fitted using the modified Apelblat equation and other models in binary solvent mixture. - Abstract: Data on corresponding solid–liquid equilibrium of 6-benzyladenine in different solvents are essential for a preliminary study of industrial applications. In this paper, the solid–liquid equilibrium of 6-benzyladenine in methanol, ethanol, 1-butanol, acetone, acetonitrile, ethyl acetate, dimethyl formamide and tetrahydrofuran pure solvents and (dimethyl formamide + actone) mixture solvents was explored within the temperature range from (278.15 to 333.15) K under 0.1 MPa. For the temperature range investigated, the solubility of 6-benzyladenine in the solvents increased with increasing temperature. The solubility of 6-benzyladenine in dimethyl formamide is superior to other selected pure solvents. The modified Apelblat model, the Buchowski-Ksiazaczak λh model, and the ideal model were adopted to describe and predict the change tendency of solubility. Computational results showed that the modified Apelblat model has more advantages than the other two models. The solubility results were fitted using a modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redich-Kister (CNIBS/R-K) model, Jouyban-Acree model and Ma model in (dimethyl formamide + acetone) binary solvent mixture. Computational results showed that the modified Apelblat model is superior to the other equations.
Directory of Open Access Journals (Sweden)
Fazel Mohammadi-Moghadam
2013-01-01
Full Text Available The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants.
Para-equilibrium phase diagrams
International Nuclear Information System (INIS)
Pelton, Arthur D.; Koukkari, Pertti; Pajarre, Risto; Eriksson, Gunnar
2014-01-01
Highlights: • A rapidly cooled system may attain a state of para-equilibrium. • In this state rapidly diffusing elements reach equilibrium but others are immobile. • Application of the Phase Rule to para-equilibrium phase diagrams is discussed. • A general algorithm to calculate para-equilibrium phase diagrams is described. - Abstract: If an initially homogeneous system at high temperature is rapidly cooled, a temporary para-equilibrium state may result in which rapidly diffusing elements have reached equilibrium but more slowly diffusing elements have remained essentially immobile. The best known example occurs when homogeneous austenite is quenched. A para-equilibrium phase assemblage may be calculated thermodynamically by Gibbs free energy minimization under the constraint that the ratios of the slowly diffusing elements are the same in all phases. Several examples of calculated para-equilibrium phase diagram sections are presented and the application of the Phase Rule is discussed. Although the rules governing the geometry of these diagrams may appear at first to be somewhat different from those for full equilibrium phase diagrams, it is shown that in fact they obey exactly the same rules with the following provision. Since the molar ratios of non-diffusing elements are the same in all phases at para-equilibrium, these ratios act, as far as the geometry of the diagram is concerned, like “potential” variables (such as T, pressure or chemical potentials) rather than like “normal” composition variables which need not be the same in all phases. A general algorithm to calculate para-equilibrium phase diagrams is presented. In the limit, if a para-equilibrium calculation is performed under the constraint that no elements diffuse, then the resultant phase diagram shows the single phase with the minimum Gibbs free energy at any point on the diagram; such calculations are of interest in physical vapor deposition when deposition is so rapid that phase
Thermodynamics of nanoadsorption from solution: Theoretical and experimental research
International Nuclear Information System (INIS)
Wen, Yan-Zhen; Xue, Yong-Qiang; Cui, Zi-Xiang; Wang, Yan
2015-01-01
Highlights: • The thermodynamic theory of nanoadsorption was proposed. • The thermodynamic relations of nanoadsorption were derived. • The results of the experiments are accord with the theory. - Abstract: In this study, the effect of nanoparticle size on adsorption thermodynamics was investigated. The results of theoretical and experimental studies show that particle size significantly affects the equilibrium constant and thermodynamic properties of nanoadsorption. Relationships between the equilibrium constant, thermodynamic properties and particle size were derived using the thermodynamic theory of nanoadsorption. The equilibrium constant and thermodynamic properties were obtained by investigating the adsorption of Cu 2+ onto different sizes of nano-ZnO and the adsorption of Ag + onto different sizes of nano-TiO 2 . Good agreement was achieved between results obtained by experiments and predicted by theoretical analyses. The equilibrium constant and the molar Gibbs free energy of nanoadsorption were found to increase with smaller nanoparticle size. However, the effects of particle size on the molar enthalpy and the molar entropy are uncertain. In addition, the molar Gibbs free energy, the molar enthalpy, the molar entropy and the logarithm of the equilibrium constant are linearly related to the reciprocal of the diameter of the nanoparticle. The thermodynamic properties revealed in this study may provide important guidelines for research and application in the field of nanoadsorption
Directory of Open Access Journals (Sweden)
N. Bhadusha
2012-01-01
Full Text Available A carbonaceous adsorbent prepared from biomass waste like wood apple outer shell (Limonia acidissima by ZnCl2 treatment was investigated for its efficiency in removing Rhodamine B (RDB. Influence of agitation time, adsorbent dose, dye concentration, pH and temperature were explored. Two theoretical adsorption isotherms namely Langmuir and Freundlich were used to describe the experimental results. The Langmuir adsorption capacity (Qo was found to be 46.7 mg/g and the equilibrium parameter (RL values indicate favourable adsorption. The experimental data were well fitted with Langmuir isotherm model and pseudo second order kinetic model. Desorption studies showed that ion exchange mechanism might be involved in the adsorption process.
Energy and thermodynamic considerations involving electromagnetic zero-point radiation
International Nuclear Information System (INIS)
Cole, Daniel C.
1999-01-01
There has been recent speculation and controversy regarding whether electromagnetic zero-point radiation might be the next candidate in the progression of plentiful energy sources, ranging, for example, from hydrodynamic, chemical, and nuclear energy sources. Certainly, however, extracting energy from the vacuum seems counter intuitive to most people. Here, these ideas are clarified, drawing on simple and common examples. Known properties of electromagnetic zero-point energy are qualitatively discussed. An outlook on the success of utilizing this energy source is then discussed
The Lewis Chemical Equilibrium Program with parametric study capability
Sevigny, R.
1981-01-01
The program was developed to determine chemical equilibrium in complex systems. Using a free energy minimization technique, the program permits calculations such as: chemical equilibrium for assigned thermodynamic states; theoretical rocket performance for both equilibrium and frozen compositions during expansion; incident and reflected shock properties; and Chapman-Jouget detonation properties. It is shown that the same program can handle solid coal in an entrained flow coal gasification problem.
Directory of Open Access Journals (Sweden)
R. Bhaumik
2012-01-01
Full Text Available A new medium, eggshell powder has been developed for fluoride removal from aqueous solution. Fluoride adsorption was studied in a batch system where adsorption was found to be pH dependent with maximum removal efficiency at 6.0. The experimental data was more satisfactorily fitted with Langmuir isotherm model. The kinetics and the factor controlling adsorption process fully accepted by pseudo-second-order model were also discussed. Ea was found to be 45.98 kJmol-1 by using Arrhenius equation, indicating chemisorption nature of fluoride onto eggshell powder. Thermodynamic study showed spontaneous nature and feasibility of the adsorption process with negative enthalpy (∆H0 value also supported the exothermic nature. Batch experiments were performed to study the applicability of the adsorbent by using fluoride contaminated water collected from affected areas. These results indicate that eggshell powder can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution as well as groundwater.
Chieng, Hei Ing; Lim, Linda B L; Priyantha, Namal
2015-01-01
Breadnut skin, in both its unmodified (KS) and base-modified (BM-KS) forms, was investigated for its potential use as a low-cost adsorbent for the removal of toxic dye, malachite green (MG). Characterization of the adsorbents was carried out using scanning electron microscope, X-ray fluorescence and Fourier transform infra-red spectroscopy. Batch adsorption experiments, carried out under optimized conditions, for the adsorption of MG were fitted using five isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Sips) and six error functions to determine the best-fit model. The adsorption capacity was greatly enhanced when breadnut skin was chemically modified with NaOH, leading to an adsorption capacity of 353.0 mg g(-1), that was far superior to most reported adsorbents for the removal of MG. Thermodynamics studies indicated that the adsorption of MG was spontaneous on KS and BM-KS, and the reactions were endothermic and exothermic, respectively. Kinetics studies showed that both followed the pseudo-second order. Regeneration experiments on BM-KS indicated that its adsorption capacity was still maintained at>90% even after five cycles. It can be concluded that NaOH-modified breadfruit skin has great potential to be utilized in real-life application as a low-cost adsorbent for the removal of MG in wastewater treatment.
Directory of Open Access Journals (Sweden)
Linda B.L. Lim
2017-05-01
Full Text Available This work reports the potential use of peel of breadnut, Artocarpus camansi, as an effective low-cost biosorbent for the removal of methylene blue (MB. Oven dried A. camansi peel (ACP, which had a point of zero charge at pH = 4.8, showed maximum biosorption capacity which was far superior to most literature reported fruit biomasses, including samples that have been activated. Isotherm studies on biosorption of MB onto ACP gave a maximum biosorption capacity of 409 mg g−1. The Langmuir model was found to give the best fit among various isotherm models investigated and error analyses performed. Kinetics studies were fast with 50% dye being removed in less than 8 min from a 50 mg L−1 dye solution and further, kinetics followed the pseudo second order. Thermodynamic studies indicated that the biosorption process was both spontaneous and exothermic. Fourier transform infrared (FT-IR of ACP before and after MB adsorption was investigated. It can be concluded that oven dried breadnut peel is a highly promising low-cost biosorbent with great potential for the removal of MB.
Heavy quark energy loss far from equilibrium in a strongly coupled collision
Chesler, Paul M; Rajagopal, Krishna
2013-01-01
We compute and study the drag force acting on a heavy quark propagating through the matter produced in the collision of two sheets of energy in a strongly coupled gauge theory that can be analyzed holographically. Although this matter is initially far from equilibrium, we find that the equilibrium expression for heavy quark energy loss in a homogeneous strongly coupled plasma with the same instantaneous energy density or pressure as that at the location of the quark describes many qualitative features of our results. One interesting exception is that there is a time delay after the initial collision before the heavy quark energy loss becomes significant. At later times, once a liquid plasma described by viscous hydrodynamics has formed, expressions based upon assuming instantaneous homogeneity and equilibrium provide a semi-quantitative description of our results - as long as the rapidity of the heavy quark is not too large. For a heavy quark with large rapidity, the gradients in the velocity of the hydrodyna...
Mielke, Alexander; Mittnenzweig, Markus
2018-04-01
We discuss how the recently developed energy dissipation methods for reaction diffusion systems can be generalized to the non-isothermal case. For this, we use concave entropies in terms of the densities of the species and the internal energy, where the importance is that the equilibrium densities may depend on the internal energy. Using the log-Sobolev estimate and variants for lower-order entropies as well as estimates for the entropy production of the nonlinear reactions, we give two methods to estimate the relative entropy by the total entropy production, namely a somewhat restrictive convexity method, which provides explicit decay rates, and a very general, but weaker compactness method.
Marginal abatement cost curves in general equilibrium: The influence of world energy prices
International Nuclear Information System (INIS)
Klepper, Gernot; Peterson, Sonja
2006-01-01
Marginal abatement cost curves (MACCs) are a favorite instrument to analyze international emissions trading. This paper focuses on the question of how to define MACCs in a general equilibrium context where the global abatement level influences energy prices and in turn national MACCs. We discuss the mechanisms theoretically and then use the CGE model DART for quantitative simulations. The result is, that changes in energy prices resulting from different global abatement levels do indeed affect national MACCs. Also, we compare different possibilities of defining MACCs-of which some are robust against changes in energy prices while others vary considerably. (author)
Generalization of Gibbs Entropy and Thermodynamic Relation
Park, Jun Chul
2010-01-01
In this paper, we extend Gibbs's approach of quasi-equilibrium thermodynamic processes, and calculate the microscopic expression of entropy for general non-equilibrium thermodynamic processes. Also, we analyze the formal structure of thermodynamic relation in non-equilibrium thermodynamic processes.
Heating without heat: Thermodynamics of passive energy filters between finite systems.
Muñoz-Tapia, R; Brito, R; Parrondo, J M R
2017-09-01
Passive filters allowing the exchange of particles in a narrow band of energy are currently used in microrefrigerators and energy transducers. In this Rapid Communication, we analyze their thermal properties using linear irreversible thermodynamics and kinetic theory, and discuss a striking phenomenon: the possibility of simultaneously increasing or decreasing the temperatures of two systems without any supply of energy. This occurs when the filter induces a flow of particles whose energy is between the average energies of the two systems. Here we show that this selective transfer of particles does not need the action of any sort of Maxwell demon and can be carried out by passive filters without compromising the second law of thermodynamics. This phenomenon allows us to design cycles between two reservoirs at temperatures T_{1}
Yi, Zhengji; Yao, Jun; Zhu, Mijia; Chen, Huilun; Wang, Fei; Liu, Xing
2016-01-01
The goal of this research is to investigate the feasibility of using activated coal-based activated carbon (CBAC) to adsorb Pb(II) from aqueous solutions through batch tests. Effects of contact time, pH, temperature and initial Pb(II) concentration on the Pb(II) adsorption were examined. The Pb(II) adsorption is strongly dependent on pH, but insensitive to temperature. The best pH for Pb(II) removal is in the range of 5.0-5.5 with more than 90 % of Pb(II) removed. The equilibrium time was found to be 60 min and the adsorption data followed the pseudo-second-order kinetics. Isotherm data followed Langmuir isotherm model with a maximum adsorption capacity of 162.33 mg/g. The adsorption was exothermic and spontaneous in nature. The Fourier transform infrared spectroscopy and scanning electron microscopy analysis suggested that CBAC possessed a porous structure and was rich in carboxyl and hydroxyl groups on its surface, which might play a major role in Pb(II) adsorption. These findings indicated that CBAC has great potential as an alternative adsorbent for Pb(II) removal.
Directory of Open Access Journals (Sweden)
Lilian Govone
2017-12-01
Full Text Available This paper presents a theoretical investigation of the second law performance of double diffusive forced convection in microreactors with the inclusion of nanofluid and radiation effects. The investigated microreactors consist of a single microchannel, fully filled by a porous medium. The transport of heat and mass are analysed by including the thick walls and a first order, catalytic chemical reaction on the internal surfaces of the microchannel. Two sets of thermal boundary conditions are considered on the external surfaces of the microchannel; (1 constant temperature and (2 constant heat flux boundary condition on the lower wall and convective boundary condition on the upper wall. The local thermal non-equilibrium approach is taken to thermally analyse the porous section of the system. The mass dispersion equation is coupled with the transport of heat in the nanofluid flow through consideration of Soret effect. The problem is analytically solved and illustrations of the temperature fields, Nusselt number, total entropy generation rate and performance evaluation criterion (PEC are provided. It is shown that the radiation effect tends to modify the thermal behaviour within the porous section of the system. The radiation parameter also reduces the overall temperature of the system. It is further demonstrated that, expectedly, the nanoparticles reduce the temperature of the system and increase the Nusselt number. The total entropy generation rate and consequently PEC shows a strong relation with radiation parameter and volumetric concentration of nanoparticles.
Fine-particle pH for Beijing winter haze as inferred from different thermodynamic equilibrium models
Directory of Open Access Journals (Sweden)
S. Song
2018-05-01
Full Text Available pH is an important property of aerosol particles but is difficult to measure directly. Several studies have estimated the pH values for fine particles in northern China winter haze using thermodynamic models (i.e., E-AIM and ISORROPIA and ambient measurements. The reported pH values differ widely, ranging from close to 0 (highly acidic to as high as 7 (neutral. In order to understand the reason for this discrepancy, we calculated pH values using these models with different assumptions with regard to model inputs and particle phase states. We find that the large discrepancy is due primarily to differences in the model assumptions adopted in previous studies. Calculations using only aerosol-phase composition as inputs (i.e., reverse mode are sensitive to the measurement errors of ionic species, and inferred pH values exhibit a bimodal distribution, with peaks between −2 and 2 and between 7 and 10, depending on whether anions or cations are in excess. Calculations using total (gas plus aerosol phase measurements as inputs (i.e., forward mode are affected much less by these measurement errors. In future studies, the reverse mode should be avoided whereas the forward mode should be used. Forward-mode calculations in this and previous studies collectively indicate a moderately acidic condition (pH from about 4 to about 5 for fine particles in northern China winter haze, indicating further that ammonia plays an important role in determining this property. The assumed particle phase state, either stable (solid plus liquid or metastable (only liquid, does not significantly impact pH predictions. The unrealistic pH values of about 7 in a few previous studies (using the standard ISORROPIA model and stable state assumption resulted from coding errors in the model, which have been identified and fixed in this study.
Cooling equilibrium and beam loss with internal targets in high energy storage rings
International Nuclear Information System (INIS)
Boine-Frankenheim, O.; Hasse, R.; Hinterberger, F.; Lehrach, A.; Zenkevich, P.
2006-01-01
The beam cooling equilibrium with internal target interaction is analyzed for parameters relevant to the proposed High Energy Storage Ring (HESR). For the proposed experiments with anti-protons high luminosities together with low momentum spreads are required. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and IBS rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beams. Analytic expressions for the target induced momentum tail are found in good agreement with the simulation results
Grams, G.; Giraud, S.; Fantina, A. F.; Gulminelli, F.
2018-03-01
The aim of the present study is to calculate the nuclear distribution associated at finite temperature to any given equation of state of stellar matter based on the Wigner-Seitz approximation, for direct applications in core-collapse simulations. The Gibbs free energy of the different configurations is explicitly calculated, with special care devoted to the calculation of rearrangement terms, ensuring thermodynamic consistency. The formalism is illustrated with two different applications. First, we work out the nuclear statistical equilibrium cluster distribution for the Lattimer and Swesty equation of state, widely employed in supernova simulations. Secondly, we explore the effect of including shell structure, and consider realistic nuclear mass tables from the Brussels-Montreal Hartree-Fock-Bogoliubov model (specifically, HFB-24). We show that the whole collapse trajectory is dominated by magic nuclei, with extremely spread and even bimodal distributions of the cluster probability around magic numbers, demonstrating the importance of cluster distributions with realistic mass models in core-collapse simulations. Simple analytical expressions are given, allowing further applications of the method to any relativistic or nonrelativistic subsaturation equation of state.
Thermodynamic free energy methods to investigate shape transitions in bilayer membranes.
Ramakrishnan, N; Tourdot, Richard W; Radhakrishnan, Ravi
2016-06-01
The conformational free energy landscape of a system is a fundamental thermodynamic quantity of importance particularly in the study of soft matter and biological systems, in which the entropic contributions play a dominant role. While computational methods to delineate the free energy landscape are routinely used to analyze the relative stability of conformational states, to determine phase boundaries, and to compute ligand-receptor binding energies its use in problems involving the cell membrane is limited. Here, we present an overview of four different free energy methods to study morphological transitions in bilayer membranes, induced either by the action of curvature remodeling proteins or due to the application of external forces. Using a triangulated surface as a model for the cell membrane and using the framework of dynamical triangulation Monte Carlo, we have focused on the methods of Widom insertion, thermodynamic integration, Bennett acceptance scheme, and umbrella sampling and weighted histogram analysis. We have demonstrated how these methods can be employed in a variety of problems involving the cell membrane. Specifically, we have shown that the chemical potential, computed using Widom insertion, and the relative free energies, computed using thermodynamic integration and Bennett acceptance method, are excellent measures to study the transition from curvature sensing to curvature inducing behavior of membrane associated proteins. The umbrella sampling and WHAM analysis has been used to study the thermodynamics of tether formation in cell membranes and the quantitative predictions of the computational model are in excellent agreement with experimental measurements. Furthermore, we also present a method based on WHAM and thermodynamic integration to handle problems related to end-point-catastrophe that are common in most free energy methods.
International Nuclear Information System (INIS)
Rahmani-Sani, Abolfazl; Hosseini-Bandegharaei, Ahmad; Hosseini, Seyyed-Hossein; Kharghani, Keivan; Zarei, Hossein; Rastegar, Ayoob
2015-01-01
Highlights: • The objective of the study is to investigate the potential application of a selective EIR for sorption of U(VI) and Th(IV) ions. • The effects of several physiochemical parameters were investigated. • The sorption kinetics and sorption isotherms were used to explain the sorption mechanism. • The thermodynamic studies showed the feasibility of sorption process. • The EIR beads showed a great potential for effective removal of U(VI) and Th(IV) ions. - Abstract: In this work, the removal of uranium and thorium ions from aqueous solutions was studied by solid–liquid extraction using an advantageous extractant-impregnated resin (EIR) prepared by loading carminic acid (CA) onto Amberlite XAD-16 resin beads. Batch sorption experiments using CA/XAD-16 beads for the removal of U(VI) and Th(IV) ions were carried out as a function of several parameters, like equilibration time, metal ion concentration, etc. The equilibrium data obtained from the sorption experiments were adjusted to the Langmuir isotherm model and the calculated maximum sorption capacities in terms of monolayer sorption were in agreement with those obtained from the experiments. The experimental data on the sorption behavior of both metal ions onto the EIR beads fitted well in both Bangham and intra-particle diffusion kinetic models, indicating that the intra-particle diffusion is the rate-controlling step. The thermodynamic studies at different temperatures revealed the feasibility and the spontaneous nature of the sorption process for both uranium and thorium ions
Dissipation and the relaxation to equilibrium
International Nuclear Information System (INIS)
Evans, Denis J; Williams, Stephen R; Searles, Debra J
2009-01-01
Using the recently derived dissipation theorem and a corollary of the transient fluctuation theorem (TFT), namely the second-law inequality, we derive the unique time independent, equilibrium phase space distribution function for an ergodic Hamiltonian system in contact with a remote heat bath. We prove under very general conditions that any deviation from this equilibrium distribution breaks the time independence of the distribution. Provided temporal correlations decay, we show that any nonequilibrium distribution that is an even function of the momenta eventually relaxes (not necessarily monotonically) to the equilibrium distribution. Finally we prove that the negative logarithm of the microscopic partition function is equal to the thermodynamic Helmholtz free energy divided by the thermodynamic temperature and Boltzmann's constant. Our results complement and extend the findings of modern ergodic theory and show the importance of dissipation in the process of relaxation towards equilibrium
Mathematical foundations of thermodynamics
Giles, R; Stark, M; Ulam, S
2013-01-01
Mathematical Foundations of Thermodynamics details the core concepts of the mathematical principles employed in thermodynamics. The book discusses the topics in a way that physical meanings are assigned to the theoretical terms. The coverage of the text includes the mechanical systems and adiabatic processes; topological considerations; and equilibrium states and potentials. The book also covers Galilean thermodynamics; symmetry in thermodynamics; and special relativistic thermodynamics. The book will be of great interest to practitioners and researchers of disciplines that deal with thermodyn
Thermodynamical research of using solar energy for desalination of seawater
Directory of Open Access Journals (Sweden)
Arsović Marjan R.
2015-01-01
Full Text Available Many regions of the world face the problem of saline water. Water desalination processes, which require significant energy consumption, are a common solution to produce drinking water. This study evaluated the influence of the following process operational parameters on the energy consumption of seawater RO systems: water salinity, permeate recovery ratio, membrane performance and feed water temperature. Optimal operational conditions for the theoretical minimum energy consumption were determined with experiments by varying water qualities and operational parameters. In order to further reduce energy consumption a RO system was integrated with a PV solar system and a pilot PVRO system was built and tested. The results obtained from this study indicated that even though a Solar PV system incurs a huge initial capital investment, it will yield significant benefits in the long run of the RO operational period.
Electronic configurations and energies in some thermodynamically correlated laves compounds
International Nuclear Information System (INIS)
Campbell, G.M.
1979-04-01
The known electronic configurations of simple elements in Laves compounds are correlated with those of the more complex systems to determine their electronic configurations and gaseous state promotion energies
International Nuclear Information System (INIS)
Pandey, Gajendra; Lambert, David L.
2017-01-01
Optical high-resolution spectra of V652 Her and HD 144941, the two extreme helium stars with exceptionally low C/He ratios, have been subjected to a non-LTE abundance analysis using the tools TLUSTY and SYNSPEC. Defining atmospheric parameters were obtained from a grid of non-LTE atmospheres and a variety of spectroscopic indicators including He i and He ii line profiles, and the ionization equilibrium of ion pairs such as C ii/C iii and N ii/N iii. The various indicators provide a consistent set of atmospheric parameters: T eff = 25,000 ± 300 K, log g = 3.10 ± 0.12(cgs), and ξ = 13 ± 2 km s −1 are provided for V652 Her, and T eff = 22,000 ± 600 K, log g = 3.45 ± 0.15 (cgs), and ξ = 10 km s −1 are provided for HD 144941. In contrast to the non-LTE analyses, the LTE analyses—LTE atmospheres and an LTE line analysis—with the available indicators do not provide a consistent set of atmospheric parameters. The principal non-LTE effect on the elemental abundances is on the neon abundance. It is generally considered that these extreme helium stars with their very low C/He ratio result from the merger of two helium white dwarfs. Indeed, the derived composition of V652 Her is in excellent agreement with predictions by Zhang and Jeffery, who model the slow merger of helium white dwarfs; a slow merger results in the merged star having the composition of the accreted white dwarf. In the case of HD 144941, which appears to have evolved from metal-poor stars, a slow merger is incompatible with the observed composition but variations of the merger rate may account for the observed composition. More detailed theoretical studies of the merger of a pair of helium white dwarfs are to be encouraged.
International Nuclear Information System (INIS)
Coudrain-Ribstein, A.
1985-01-01
This study is a contribution of analyses possibilities of modelling the transfer of components in the underground taking into account complexes geochemical phenomena. In the first part, the aim and the methodology of existing codes are presented. The transfer codes describe with a great precision the physical phenomena of transport but they are based on a very simple conceptualisation of the geochemical phenomena of retention by the rock. The geochemical models are interested by a stable unity of volume. They allow to compute the equilibrium distribution of the components between the chemical species of the solution, and the solid and gaseous phases. They use important thermodynamic data bases corresponding to each possible reaction. To sum up the situation about the geochemical codes in Europe and United States, a list of about thirty codes describe their method and potentialities. The mathematical analysis of the different methods used in both types of codes is presented. Then, the principles of a modelisation associating the potentialities of the transport codes and the geochemical codes are discussed. It is not possible to think of a simple coupling. A general code must be established on the bases of the existing codes but also on new concepts and under new constraints. In such studies one must always deal with the problem of the reactions kinetics. When the velocity of the reactions is big enough versus the velocity of transport processes, the assumption of local geochemical equilibrium can be retained. A general code would be very cumbersome, expensive and difficult to use. The results would be difficult to analyse and exploit. On the other hand, for each case study, a detailed analysis can point out many computing simplifications without simplifying the concepts [fr
Naushad, Mu; Alothman, Z A; Khan, M R
2013-10-15
In the present study, De-Acidite FF-IP resin was used to remove a highly toxic and persistent organophosphorus pesticide (malathion) from the aqueous solution. Batch experiments were performed as a function of various experimental parameters such as effect of pH (2-10), contact time (10-120 min), resin dose (0.05-0.5 g), initial malathion concentration (0.5-2.5 µg mL(-1)) and temperature (25-65°C). The concentration of malathion was determined using a sensitive, selective and rapid ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. The uptake rate of malathion on De-Acidite FF-IP resin was rapid and equilibrium established within 40 min. Kinetics studies showed better applicability for pseudo-second-order model. The equilibrium data was fitted to Langmuir and Freundlich isotherm models and the isotherm constants were calculated for malathion. The values of thermodynamic parameters (ΔG(0), ΔH(0) and ΔS(0)) were computed from the Van't Hoff plot of lnKC vs. 1/T which showed that the adsorption of malathion was feasible, endothermic and spontaneous. The regeneration studies were carried out which demonstrated a decrease in the recovery of malathion from 95% to 68% after five consecutive cycles. Breakthrough and exhaustive capacities of malathion were found to be 1.25 mg g(-1) and 3.5 mg g(-1), respectively. © 2013 Elsevier B.V. All rights reserved.
Stochastic programming and market equilibrium analysis of microgrids energy management systems
International Nuclear Information System (INIS)
Hu, Ming-Che; Lu, Su-Ying; Chen, Yen-Haw
2016-01-01
Microgrids facilitate optimum utilization of distributed renewable energy, provides better local energy supply, and reduces transmission loss and greenhouse gas emission. Because the uncertainty in energy demand affects the energy demand and supply system, the aim of this research is to develop a stochastic optimization and its market equilibrium for microgrids in the electricity market. Therefore, a two-stage stochastic programming model for microgrids and the market competition model are derived in this paper. In the stochastic model, energy demand and supply uncertainties are considered. Furthermore, a case study of the stochastic model is conducted to simulate the uncertainties on the INER microgrids in Taiwanese market. The optimal investment of the generators and batteries installation and operating strategies are determined under energy demand and supply uncertainties for the INER microgrids. The results show optimal investment and operating strategies for the current INER microgrids are also determined by the proposed two-stage stochastic model in the market. In addition, trade-off between the battery capacity and microgrids performance is investigated. Battery usage and power trading between the microgrids and main grid systems are the functions of battery capacity. - Highlights: • A two-stage stochastic programming model is developed for microgrids. • Market equilibrium analysis of microgrids is conducted. • A case study of the stochastic model is conducted for INER microgrids.
International Nuclear Information System (INIS)
Gaschi, Priscilla S.; Mafra, Marcos R.; Ndiaye, Papa M.; Corazza, Marcos L.
2013-01-01
Graphical abstract: Ethyl palmitate and biodiesel comparison in a pressure–composition diagram for the systems (CO 2 + ethyl palmitate + biodiesel), at different temperatures. Highlights: ► We measured VLE, LLE, and VLLE for the system (CO 2 + ethyl palmitate + ethanol). ► The saturation pressures were obtained using a variable-volume view cell. ► Phase envelope of (CO 2 + ethyl palmitate) is different that (CO 2 + soybean oil biodiesel). ► The experimental data were modeled using PR-vdW2 and PR–WS equations of state. - Abstract: This work reports phase equilibrium measurements for the binary {CO 2 (1) + ethyl palmitate(2)} and ternary {CO 2 (1) + ethyl palmitate(2) + ethanol(3)} systems at high pressures. There is currently great interest in biodiesel production processes involving supercritical and/or pressurized solvents, such as non-catalytic supercritical biodiesel production and enzyme-catalysed biodiesel production. Also, supercritical CO 2 can offer an interesting alternative for glycerol separation in the biodiesel purification step in a water-free process. In this context, the main goal of this work was to investigate the phase behaviour of binary and ternary systems involving CO 2 , a pure constituent of biodiesel ethyl palmitate and ethanol. Experiments were carried out in a high-pressure variable-volume view cell with operating temperatures ranging from (303.15 to 353.15) K and pressures up to 21 MPa. The CO 2 mole fraction ranged from 0.5033 to 0.9913 for the binary {CO 2 (1) + ethyl palmitate(2)} system and from 0.4436 to 0.9712 for ternary system {CO 2 (1) + ethyl palmitate(2) + ethanol(3)} system with ethyl ester to ethanol molar ratios of (1:6), (1:3), and (1:1). For the systems investigated, vapour–liquid (VL), liquid–liquid (LL) and vapour–liquid–liquid (VLL) phase transitions were observed. The experimental data sets were successfully modeled using the Peng–Robinson equation of state with the classical van der Waals
Energy Technology Data Exchange (ETDEWEB)
Pandey, Gajendra [Indian Institute of Astrophysics, Bangalore, 560034 (India); Lambert, David L., E-mail: pandey@iiap.res.in, E-mail: dll@astro.as.utexas.edu [The W.J. McDonald Observatory and Department of Astronomy, University of Texas at Austin, Austin, TX 78712-1083 (United States)
2017-10-01
Optical high-resolution spectra of V652 Her and HD 144941, the two extreme helium stars with exceptionally low C/He ratios, have been subjected to a non-LTE abundance analysis using the tools TLUSTY and SYNSPEC. Defining atmospheric parameters were obtained from a grid of non-LTE atmospheres and a variety of spectroscopic indicators including He i and He ii line profiles, and the ionization equilibrium of ion pairs such as C ii/C iii and N ii/N iii. The various indicators provide a consistent set of atmospheric parameters: T {sub eff} = 25,000 ± 300 K, log g = 3.10 ± 0.12(cgs), and ξ = 13 ± 2 km s{sup −1} are provided for V652 Her, and T {sub eff} = 22,000 ± 600 K, log g = 3.45 ± 0.15 (cgs), and ξ = 10 km s{sup −1} are provided for HD 144941. In contrast to the non-LTE analyses, the LTE analyses—LTE atmospheres and an LTE line analysis—with the available indicators do not provide a consistent set of atmospheric parameters. The principal non-LTE effect on the elemental abundances is on the neon abundance. It is generally considered that these extreme helium stars with their very low C/He ratio result from the merger of two helium white dwarfs. Indeed, the derived composition of V652 Her is in excellent agreement with predictions by Zhang and Jeffery, who model the slow merger of helium white dwarfs; a slow merger results in the merged star having the composition of the accreted white dwarf. In the case of HD 144941, which appears to have evolved from metal-poor stars, a slow merger is incompatible with the observed composition but variations of the merger rate may account for the observed composition. More detailed theoretical studies of the merger of a pair of helium white dwarfs are to be encouraged.
International Nuclear Information System (INIS)
Vakalis, S.; Patuzzi, F.; Baratieri, M.
2017-01-01
Highlights: • Analysis of plants for electricity, heat and materials production. • Thermodynamic analysis by using exergy, entransy and statistical entropy. • Extrapolation of a single efficiency index by combining the thermodynamic parameters. • Application of methodology for two monitored small scale gasifiers. - Abstract: Modern gasification plants, should be treated as poly-generation facilities because, alongside the production of electricity and heat, valuable or waste materials streams are generated. Thus, integrated methods should be introduced in order to account for the full range and the nature of the products. Application of conventional hybrid indicators that convert the output into monetary units or CO_2 equivalents are a source of bias because of the inconsistency of the conversion factors and unreliability of the available data. Therefore, this study introduces a novel thermodynamic-based method for assessing gasification plants performance by means of exergy, entransy and statistical entropy. A monitoring campaign has been implemented on two small scale gasifiers and the results have been applied on the proposed method. The energy plants are compared in respect to their individual thermodynamic parameters for energy production and materials distribution. In addition, the method returns one single value which is a resultant of all the investigated parameters and is a characteristic value of the overall performance of an energy plant.
Yip, Ngai Yin; Elimelech, Menachem
2012-05-01
The Gibbs free energy of mixing dissipated when fresh river water flows into the sea can be harnessed for sustainable power generation. Pressure retarded osmosis (PRO) is one of the methods proposed to generate power from natural salinity gradients. In this study, we carry out a thermodynamic and energy efficiency analysis of PRO work extraction. First, we present a reversible thermodynamic model for PRO and verify that the theoretical maximum extractable work in a reversible PRO process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible constant-pressure PRO process is then examined. We derive an expression for the maximum extractable work in a constant-pressure PRO process and show that it is less than the ideal work (i.e., Gibbs free energy of mixing) due to inefficiencies intrinsic to the process. These inherent inefficiencies are attributed to (i) frictional losses required to overcome hydraulic resistance and drive water permeation and (ii) unutilized energy due to the discontinuation of water permeation when the osmotic pressure difference becomes equal to the applied hydraulic pressure. The highest extractable work in constant-pressure PRO with a seawater draw solution and river water feed solution is 0.75 kWh/m(3) while the free energy of mixing is 0.81 kWh/m(3)-a thermodynamic extraction efficiency of 91.1%. Our analysis further reveals that the operational objective to achieve high power density in a practical PRO process is inconsistent with the goal of maximum energy extraction. This study demonstrates thermodynamic and energetic approaches for PRO and offers insights on actual energy accessible for utilization in PRO power generation through salinity gradients. © 2012 American Chemical Society
Energy Technology Data Exchange (ETDEWEB)
Varghese, Lina Rose; Das, Devlina; Das, Nilanjana [VIT University, Tamil Nadu (India)
2016-01-15
The current study presents a novel approach for the removal of Ni(II) from aqueous environments using plant gum-based (PG) and clay-based (CL) nanobiocomposite (NBC) composed of ZnO nanoparticles and chitosan. Parameters like pH, contact time, temperature, initial metal concentration and adsorbent dosage were optimized. Under optimized conditions, maximum removal of Ni(II) was noted as 90.1% and 95.5% in the case of PG-NBC and CLNBC, respectively. Equilibrium studies suggested a homogeneous mode of adsorption. Good linearity was observed for the pseudo-first order kinetic model, suggesting a physical mode of adsorption. Thermodynamic studies showed an endothermic and spontaneous nature of adsorption. The mechanism was further elucidated using SEM, EDX, AFM and FT-IR analysis. Ex-situ studies showed a maximum Ni(II) removal of 87.34% from electroplating wastewater using CL-NBC in column mode. Regeneration studies suggested that CL-NBC could be consistently reused up to 4 cycles.
International Nuclear Information System (INIS)
Bakshi, V.
1988-01-01
The Stark widths of seven Ar I transitions are reported. Axial line shape data from an atmospheric d.c. argon plasma jet were Abel-inverted to obtain radial line shapes. The electron-density was determined by Stark width measurements of the hydrogen H β transition. In the electron-density region of ≤6 x 10 22 m -3 the experimental Ar I Stark widths are fitted to a linear dependence on the electron-density. Values of Stark width extrapolated to other electron densities are compared to measurements reported in the literature on the 4s-4p array. Experimental values are up to 45% smaller than those predicted by Griem's theory of Stark broadening. Conditions for local thermodynamic equilibrium (LTE) to exist in an atmospheric argon plasma jet were studied. The experiment measures the emission coefficient of seven Ar I transitions and the line shape of the hydrogen H beta transition. After transforming the side-on data into radial space the excited neutral argon atom-density and the electron-density are determined. It is found LTE does not exist below an electron-density of 6 x 10 33 m -3 in the experimental conditions
Energy, economy and equity interactions in a CGE [Computable General Equilibrium] model for Pakistan
International Nuclear Information System (INIS)
Naqvi, Farzana
1997-01-01
In the last three decades, Computable General Equilibrium modelling has emerged as an established field of applied economics. This book presents a CGE model developed for Pakistan with the hope that it will lay down a foundation for application of general equilibrium modelling for policy formation in Pakistan. As the country is being driven swiftly to become an open market economy, it becomes vital to found out the policy measures that can foster the objectives of economic planning, such as social equity, with the minimum loss of the efficiency gains from the open market resource allocations. It is not possible to build a model for practical use that can do justice to all sectors of the economy in modelling of their peculiar features. The CGE model developed in this book focuses on the energy sector. Energy is considered as one of the basic needs and an essential input to economic growth. Hence, energy policy has multiple criteria to meet. In this book, a case study has been carried out to analyse energy pricing policy in Pakistan using this CGE model of energy, economy and equity interactions. Hence, the book also demonstrates how researchers can model the fine details of one sector given the core structure of a CGE model. (UK)
Inquiries into the Nature of Free Energy and Entropy in Respect to Biochemical Thermodynamics
Directory of Open Access Journals (Sweden)
Clinton D. Stoner
2000-08-01
Full Text Available Free energy and entropy are examined in detail from the standpoint of classical thermodynamics. The approach is logically based on the fact that thermodynamic work is mediated by thermal energy through the tendency for nonthermal energy to convert spontaneously into thermal energy and for thermal energy to distribute spontaneously and uniformly within the accessible space. The fact that free energy is a Second-Law, expendable energy that makes it possible for thermodynamic work to be done at finite rates is emphasized. Entropy, as originally defined, is pointed out to be the capacity factor for thermal energy that is hidden with respect to temperature; it serves to evaluate the practical quality of thermal energy and to account for changes in the amounts of latent thermal energies in systems maintained at constant temperature. With entropy thus operationally defined, it is possible to see that TDSÃ‚Â° of the Gibbs standard free energy relation DGÃ‚Â°= DHÃ‚Â°-TDSÃ‚Â° serves to account for differences or changes in nonthermal energies that do not contribute to DGÃ‚Â° and that, since DHÃ‚Â° serves to account for differences or changes in total energy, complete enthalpy-entropy (DHÃ‚Â° - TDSÃ‚Â° compensation must invariably occur in isothermal processes for which TDSÃ‚Â° is finite. A major objective was to clarify the means by which free energy is transferred and conserved in sequences of biological reactions coupled by freely diffusible intermediates. In achieving this objective it was found necessary to distinguish between a 'characteristic free energy' possessed by all First-Law energies in amounts equivalent to the amounts of the energies themselves and a 'free energy of concentration' that is intrinsically mechanical and relatively elusive in that it can appear to be free of First-Law energy. The findings in this regard serve to clarify the fact that the transfer of chemical potential energy from one
Tel, E.; Kaplan, A.; Aydın, A.; Özkorucuklu, S.; Büyükuslu, H.; Yıldırım, G.
2010-08-01
Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, working out the systematics of ( n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, ( n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.
Nonequilibrium thermodynamics and information theory: basic concepts and relaxing dynamics
International Nuclear Information System (INIS)
Altaner, Bernhard
2017-01-01
Thermodynamics is based on the notions of energy and entropy. While energy is the elementary quantity governing physical dynamics, entropy is the fundamental concept in information theory. In this work, starting from first principles, we give a detailed didactic account on the relations between energy and entropy and thus physics and information theory. We show that thermodynamic process inequalities, like the second law, are equivalent to the requirement that an effective description for physical dynamics is strongly relaxing. From the perspective of information theory, strongly relaxing dynamics govern the irreversible convergence of a statistical ensemble towards the maximally non-commital probability distribution that is compatible with thermodynamic equilibrium parameters. In particular, Markov processes that converge to a thermodynamic equilibrium state are strongly relaxing. Our framework generalizes previous results to arbitrary open and driven systems, yielding novel thermodynamic bounds for idealized and real processes. (paper)
Energy Technology Data Exchange (ETDEWEB)
Faussurier, G.
1996-12-31
A new screened hydrogenic model is presented. The screening constants depend both on the principal n and orbital l quantum numbers. They have been obtained from numerical fits over a large data base containing ionization potentials and one-electron excitation energies of ions. A rapid and original method to compute the bound-bound and bound-free oscillator strengths is proposed. The discrete spectrum and the series continuum are connected by continuity, and the sum rules are respected. The screened hydrogenic average atom is well-adapted to describe multicharged ion plasmas in local thermodynamic equilibrium (LTE). Using the key principle of statistical mechanics, it is shown first that this model is properly defined and thermodynamically coherent. Secondly, a new method of detailed ionization stage accounting of a LTE plasma is explained. It can be used to reconstruct the distribution of integer charge states in such a plasma from any average atom model. The l -splitting allows one-electron transitions between two subshells with the same principal quantum number n. They may be of great importance when the Rosseland opacity is computed. Though, methods of classical statistical mechanics are required to calculate the distribution of the configurations around the average atom one and so to improve the spectral opacities. The splitting in integer ionic stages can be easily included. The formalism is tested by comparisons with theoretical and experimental results published in the literature. From the photoabsorption spectra encountered, the main results are the correct estimations of both the Rosseland opacity and the detailed charge degrees accounting. (author).
Thermodynamics of interacting holographic dark energy with the apparent horizon as an IR cutoff
International Nuclear Information System (INIS)
Sheykhi, Ahmad
2010-01-01
As soon as an interaction between holographic dark energy and dark matter is taken into account, the identification of an IR cutoff with the Hubble radius H -1 , in a flat universe, can simultaneously drive accelerated expansion and solve the coincidence problem. Based on this, we demonstrate that in a non-flat universe the natural choice for the IR cutoff could be the apparent horizon radius, r-tilde A =1/√(H 2 +k/a 2 ). We show that any interaction of dark matter with holographic dark energy, whose infrared cutoff is set by the apparent horizon radius, implies an accelerated expansion and a constant ratio of the energy densities of both components thus solving the coincidence problem. We also verify that for a universe filled with dark energy and dark matter, the Friedmann equation can be written in the form of the modified first law of thermodynamics, dE = T h dS h + WdV, at the apparent horizon. In addition, the generalized second law of thermodynamics is fulfilled in a region enclosed by the apparent horizon. These results hold regardless of the specific form of dark energy and interaction term. Our study might reveal that in an accelerating universe with spatial curvature, the apparent horizon is a physical boundary from the thermodynamical point of view.
International Nuclear Information System (INIS)
El-Emam, Rami Salah; Dincer, Ibrahim
2014-01-01
This paper investigates the performance of a RO (reverse osmosis) desalination plant at different seawater salinity values. An energy recovery Pelton turbine is integrated with the desalination plant. Thermodynamic analysis, based on the first and second laws of thermodynamics, as well as a thermo-based economic analysis is performed for the proposed system. The effects of the system components irreversibilities on the economics and cost of product water are parametrically studied through the thermoeconomic analysis. The exergy analysis shows that large irreversibilities occur in the high pressure pump and in the RO module. Both thermodynamic and thermoeconomic performances of the overall system are investigated under different operating parameters. For the base case; the system achieves an exergy efficiency of 5.82%. The product cost is estimated to be 2.451 $/m 3 and 54.2 $/MJ when source water with salinity of 35,000 ppm is fed to the system. - Highlights: • Thermodynamic and exergoeconomic analyses are performed for SWRO with energy recovery. • Parametric studies are done to study effects of operating conditions on performance. • Different seawater sources with different salinity values are tested. • At base case, plant exergy efficiency is 5.82% and product cost is 2.451 $/m 3
Ben-Naim, Arieh
2017-01-01
This textbook introduces thermodynamics with a modern approach, starting from four fundamental physical facts (the atomic nature of matter, the indistinguishability of atoms and molecules of the same species, the uncertainty principle, and the existence of equilibrium states) and analyzing the behavior of complex systems with the tools of information theory, in particular with Shannon's measure of information (or SMI), which can be defined on any probability distribution. SMI is defined and its properties and time evolution are illustrated, and it is shown that the entropy is a particular type of SMI, i.e. the SMI related to the phase-space distribution for a macroscopic system at equilibrium. The connection to SMI allows the reader to understand what entropy is and why isolated systems follow the Second Law of Thermodynamics. The Second Llaw is also formulated for other systems, not thermally isolated and even open with respect to the transfer of particles. All the fundamental aspects of thermodynamics are d...
Directory of Open Access Journals (Sweden)
Zhanqiang Huo
2017-01-01
Full Text Available Wireless regional area network (WRAN adopts centralized network architecture and is currently one of the most typical cognitive radio networks. In order to reduce the energy consumption of the communication networks with the constraint of spectrum resource utilization, a working sleep mechanism is introduced into the base station (BS, and a novel energy saving strategy with dual rate transmission is proposed. Combining the multiple-vacation queue and priority queue, using the quasi-birth-death process and the matrix-geometric solution method, we assess the average latency and the forced termination probability of secondary user packets, as well as the energy saving ratio and the channel utilization of system. Based on the revenue-expenditure structure, a profit function is built, and then the Nash equilibrium behavior and the socially optimal behavior are investigated. With the help of the particle swarm optimization, an intelligent optimization algorithm to search the socially optimal arrival rate of secondary user packets is presented. In order to unify the arrival rates of secondary user packets with Nash equilibrium and social optimization, a reasonable pricing policy is formulated. In addition, system experiments are carried out to verify the effectiveness of the energy saving strategy and the rationality of the pricing policy.
International Nuclear Information System (INIS)
Siddiqui, Sauleh; Christensen, Adam
2016-01-01
Energy and climate market policy is inherently multiobjective and multilevel, in that desired choices often conflict and are made at a higher level than influenced actors. Analyzing tradeoff between reducing emissions and keeping fuel prices low, while seeking compromise among producers, traders, and consumers is the crux of the policy problem. This paper aims to address this issue by combining multiobjective optimization problems, which allow the study of tradeoff between choices, with equilibrium problems that model the networks and players over which these policies are chosen, to produce a formulation called a Multiobjective Program with Equilibrium Constraints. We apply this formulation to the United States renewable fuel market to help understand why it has been so difficult in releasing the 2014 mandate for the RFS (Renewable Fuel Standard). The RFS ensures that a minimum volume of renewable fuel is included in transportation fuel sold in the United States. Determining the RFS volume requirements involves anticipating market reaction as well as balancing policy objectives. We provide policy alternatives to aid in setting these volume obligations that are applicable to a wide variety of climate and energy market settings and explain why the RFS is not an optimal policy for reducing emissions. - Highlights: • First time a MOPEC has been used to model energy markets and climate policy. • Method to endogenously determine energy policy along with associated tradeoff. • Computationally efficient algorithm for MOPECs and compare to methods. • Explain why the RFS is not an optimal policy for emission reduction.
Communication: Thermodynamics of condensed matter with strong pressure-energy correlations
DEFF Research Database (Denmark)
Ingebrigtsen, Trond; Bøhling, Lasse; Schrøder, Thomas
2012-01-01
We show that for any liquid or solid with strong correlation between its NVT virial and potential-energy equilibrium fluctuations, the temperature is a product of a function of excess entropy per particle and a function of density, T = f(s)h(ρ). This implies that (1) the system's isomorphs (curve...
Advanced classical thermodynamics
International Nuclear Information System (INIS)
Emanuel, G.
1987-01-01
The theoretical and mathematical foundations of thermodynamics are presented in an advanced text intended for graduate engineering students. Chapters are devoted to definitions and postulates, the fundamental equation, equilibrium, the application of Jacobian theory to thermodynamics, the Maxwell equations, stability, the theory of real gases, critical-point theory, and chemical thermodynamics. Diagrams, graphs, tables, and sample problems are provided. 38 references
International Nuclear Information System (INIS)
Belkhiri, Madeny
2014-01-01
In hot dense plasmas, the free-electron and ion spatial distribution may strongly affect the atomic structure. To account for such effects we have implemented a potential correction based on the uniform electron gas model and on a Thomas-Fermi Approach in the Flexible Atomic Code (FAC). This code has been applied to obtain energies, wave-functions and radiative rates modified by the plasma environment. In hydrogen-like ions, these numerical results have been successfully compared to an analytical calculation based on first-order perturbation theory. In the case of multi-electron ions, we observe level crossings in agreement with another recent model calculation. Various methods for the collision cross-section calculations are reviewed. The influence of plasma environment on these cross-sections is analyzed in detail. Some analytical expressions are proposed for hydrogen-like ions in the limit where Born or Lotz approximations apply and are compared to the numerical results from the FAC code. Finally, from this work, we study the influence of the plasma environment on our collisional-radiative model so-called Foch. Because of this environment, the mean charge state of the ions increases. The line shift is observed on the bound-bound emission spectra. A good agreement is found between our work and experimental data on a Titanium plasma. (author) [fr
International Nuclear Information System (INIS)
White, J.; Cummings, A.; Dunne, P.; Hayden, P.; O'Sullivan, G.
2007-01-01
Extreme ultraviolet lithography schemes for the semiconductor industry are currently based on coupling radiation from a plasma source into a 2% bandwidth at 13.5 nm (91.8 eV). In this paper, we consider the case for a laser-produced plasma (LPP) and address the calculation of ionic level populations in the 4p 6 4d N , 4p 6 4d N-1 4f 1 , 4p 5 4d N+1 , and 4p 6 4d N-1 5p 1 configurations in a range of tin ions (Sn 6+ to Sn 13+ ) producing radiation in this bandwidth. The LPP is modeled using a one-dimensional hydrodynamics code, which uses a hydrogenic, average atom model, where the level populations are treated as l degenerate. Hartree-Fock calculations are used to remove the l degeneracy and an energy functional method to calculate the nl level populations involved in n=4-4 transitions as a function of distance from the target surface and time. Detailed data are presented for the tin ions that contribute to in-band emission
Thermodynamic analysis of a milk pasteurization process assisted by geothermal energy
International Nuclear Information System (INIS)
Yildirim, Nurdan; Genc, Seda
2015-01-01
Renewable energy system is an important concern for sustainable development of the World. Thermodynamic analysis, especially exergy analysis is an intense tool to assess sustainability of the systems. Food processing industry is one of the energy intensive sectors where dairy industry consumes substantial amount of energy among other food industry segments. Therefore, in this study, thermodynamic analysis of a milk pasteurization process assisted by geothermal energy was studied. In the system, a water–ammonia VAC (vapor absorption cycle), a cooling section, a pasteurizer and a regenerator were used for milk pasteurization. Exergetic efficiencies of each component and the whole system were separately calculated. A parametric study was undertaken. In this regard, firstly the effect of the geothermal resource temperature on (i) the total exergy destruction of the absorption cycle and the whole system, (ii) the efficiency of the VAC, the whole system and COP (coefficient of performance) of the VAC, (iii) the flow rate of the pasteurized milk were investigated. Then, the effect of the geothermal resource flow rate on the pasteurization load was analyzed. The exergetic efficiency of the whole system was calculated as 56.81% with total exergy destruction rate of 13.66 kW. The exergetic results were also illustrated through the Grassmann diagram. - Highlights: • Geothermal energy assisted milk pasteurization system was studied thermodynamically. • The first study on exergetic analysis of a milk pasteurization process with VAC. • The thermodynamic properties of water–ammonia mixture were calculated by using EES. • Energetic and exergetic efficiency calculated as 71.05 and 56.81%, respectively.
Shi, Renhai
Organic polyalcohol and amine globular molecular crystal materials as phase change materials (PCMs) such as Pentaglycerine (PG-(CH3)C(CH 2OH)3), Tris(hydroxymethyl)aminomethane (TRIS-(NH2)C(CH 2OH)3), 2-amino-2methyl-1,3-propanediol (AMPL-(NH2)(CH3)C(CH2OH)2), and neopentylglycol (NPG-(CH3)2C(CH2OH) 2) can be considered to be potential candidates for thermal energy storage (TES) applications such as waste heat recovery, solar energy utilization, energy saving in buildings, and electronic device management during heating or cooling process in which the latent heat and sensible heat can be reversibly stored or released through solid state phase transitions over a range of temperatures. In order to understand the polymorphism of phase transition of these organic materials and provide more choice of materials design for TES, binary systems have been studied to lower the temperature of solid-state phase transition for the specific application. To our best knowledge, the study of ternary systems in these organic materials is limited. Based on this motivation, four ternary systems of PG-TRIS-AMPL, PG-TRIS-NPG, PG-AMPL-NPG, and TRIS-AMPL-NPG are proposed in this dissertation. Firstly, thermodynamic assessment with CALPHAD method is used to construct the Gibbs energy functions into thermodynamic database for these four materials based on available experimental results from X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The phase stability and thermodynamic characteristics of these four materials calculated from present thermodynamic database with CALPHAD method can match well the present experimental results from XRD and DSC. Secondly, related six binary phase diagrams of PG-TRIS, PG-AMPL, PG-NPG, TRIS-AMPL, TRIS-NPG, and AMPL-NPG are optimized with CALPHAD method in Thermo-Calc software based on available experimental results, in which the substitutional model is used and excess Gibbs energy is expressed with Redlich-Kister formalism. The
Choice of the thermodynamic variables
International Nuclear Information System (INIS)
Balian, R.
1985-09-01
Some basic ideas of thermodynamics and statistical mechanics, both at equilibrium and off equilibrium, are recalled. In particular, the selection of relevant variables which underlies any macroscopic description is discussed, together with the meaning of the various thermodynamic quantities, in order to set the thermodynamic approaches used in nuclear physics in a general prospect [fr
Thermodynamic characteristics of a novel supercritical compressed air energy storage system
International Nuclear Information System (INIS)
Guo, Huan; Xu, Yujie; Chen, Haisheng; Zhou, Xuezhi
2016-01-01
Highlights: • A novel supercritical compressed air energy storage system is proposed. • The energy density of SC-CAES is approximately 18 times larger than that of conventional CAES. • The characteristic of thermodynamics and exergy destruction is comprehensively analysed. • The corresponding optimum relationship between charging and discharging pressure is illustrated. • A turning point of efficiency is indicated because of the heat transfer of crossing the critical point. - Abstract: A novel supercritical compressed air energy storage (SC-CAES) system is proposed by our team to solve the problems of conventional CAES. The system eliminates the dependence on fossil fuel and large gas-storage cavern, as well as possesses the advantages of high efficiency by employing the special properties of supercritical air, which is significant for the development of electrical energy storage. The thermodynamic model of the SC-CAES system is built, and the thermodynamic characters are revealed. Through the exergy analysis of the system, the processes of the larger exergy destruction include compression, expansion, cold storage/heat exchange and throttle. Furthermore, sensitivity analysis shows that there is an optimal energy releasing pressure to make the system achieve the highest efficiency when energy storage pressure is constant. The efficiency of SC-CAES is expected to reach about 67.41% when energy storage pressure and energy releasing pressure are 120 bar and 95.01 bar, respectively. At the same time, the energy density is 18 times larger than that of conventional CAES. Sensitivity analysis also shows the change laws of system efficiency varying with other basic system parameters. The study provides support for the design and engineering of SC-CAES.
Integrated environmental assessment of future energy scenarios based on economic equilibrium models
International Nuclear Information System (INIS)
Igos, E.; Rugani, B.; Rege, S.; Benetto, E.; Drouet, L.; Zachary, D.; Haas, T.
2014-01-01
The future evolution of energy supply technologies strongly depends on (and affects) the economic and environmental systems, due to the high dependency of this sector on the availability and cost of fossil fuels, especially on the small regional scale. This paper aims at presenting the modeling system and preliminary results of a research project conducted on the scale of Luxembourg to assess the environmental impact of future energy scenarios for the country, integrating outputs from partial and computable general equilibrium models within hybrid Life Cycle Assessment (LCA) frameworks. The general equilibrium model for Luxembourg, LUXGEM, is used to evaluate the economic impacts of policy decisions and other economic shocks over the time horizon 2006-2030. A techno-economic (partial equilibrium) model for Luxembourg, ETEM, is used instead to compute operation levels of various technologies to meet the demand for energy services at the least cost along the same timeline. The future energy demand and supply are made consistent by coupling ETEM with LUXGEM so as to have the same macro-economic variables and energy shares driving both models. The coupling results are then implemented within a set of Environmentally-Extended Input-Output (EE-IO) models in historical time series to test the feasibility of the integrated framework and then to assess the environmental impacts of the country. Accordingly, a dis-aggregated energy sector was built with the different ETEM technologies in the EE-IO to allow hybridization with Life Cycle Inventory (LCI) and enrich the process detail. The results show that the environmental impact slightly decreased overall from 2006 to 2009. Most of the impacts come from some imported commodities (natural gas, used to produce electricity, and metalliferous ores and metal scrap). The main energy production technology is the combined-cycle gas turbine plant 'Twinerg', representing almost 80% of the domestic electricity production in Luxembourg
Equilibrium Propagation: Bridging the Gap between Energy-Based Models and Backpropagation
Directory of Open Access Journals (Sweden)
Benjamin Scellier
2017-05-01
Full Text Available We introduce Equilibrium Propagation, a learning framework for energy-based models. It involves only one kind of neural computation, performed in both the first phase (when the prediction is made and the second phase of training (after the target or prediction error is revealed. Although this algorithm computes the gradient of an objective function just like Backpropagation, it does not need a special computation or circuit for the second phase, where errors are implicitly propagated. Equilibrium Propagation shares similarities with Contrastive Hebbian Learning and Contrastive Divergence while solving the theoretical issues of both algorithms: our algorithm computes the gradient of a well-defined objective function. Because the objective function is defined in terms of local perturbations, the second phase of Equilibrium Propagation corresponds to only nudging the prediction (fixed point or stationary distribution toward a configuration that reduces prediction error. In the case of a recurrent multi-layer supervised network, the output units are slightly nudged toward their target in the second phase, and the perturbation introduced at the output layer propagates backward in the hidden layers. We show that the signal “back-propagated” during this second phase corresponds to the propagation of error derivatives and encodes the gradient of the objective function, when the synaptic update corresponds to a standard form of spike-timing dependent plasticity. This work makes it more plausible that a mechanism similar to Backpropagation could be implemented by brains, since leaky integrator neural computation performs both inference and error back-propagation in our model. The only local difference between the two phases is whether synaptic changes are allowed or not. We also show experimentally that multi-layer recurrently connected networks with 1, 2, and 3 hidden layers can be trained by Equilibrium Propagation on the permutation-invariant MNIST
Non-equilibrium QCD of high-energy multi-gluon dynamics
International Nuclear Information System (INIS)
Geiger, K.
1996-01-01
A non-equilibrium QCD description of multiparticle dynamics in space-time is of both fundamental and phenomenological interest. Here the authors discusses an attempt to derive from first principles, a real-time formalism to study the dynamical interplay of quantum and statistical-kinetic properties of non-equilibrium multi-parton systems produced in high-energy QCD processes. The ultimate goal (from which one is still far away) is to have a practically applicable description of the space-time evolution of a general initial system of gluons and quarks, characterized by some large energy or momentum scale, that expands, diffuses and dissipates according to the self- and mutual-interactions, and eventually converts dynamically into final state hadrons. For example, the evolution of parton showers in the mechanism of parton-hadron conversion in high-energy hadronic collisions, or, the description of formation, evolution and freezeout of a quark-gluon plasma, in ultra-relativistic heavy-ion collisions
The thermodynamic properties of the upper continental crust: Exergy, Gibbs free energy and enthalpy
International Nuclear Information System (INIS)
Valero, Alicia; Valero, Antonio; Vieillard, Philippe
2012-01-01
This paper shows a comprehensive database of the thermodynamic properties of the most abundant minerals of the upper continental crust. For those substances whose thermodynamic properties are not listed in the literature, their enthalpy and Gibbs free energy are calculated with 11 different estimation methods described in this study, with associated errors of up to 10% with respect to values published in the literature. Thanks to this procedure we have been able to make a first estimation of the enthalpy, Gibbs free energy and exergy of the bulk upper continental crust and of each of the nearly 300 most abundant minerals contained in it. Finally, the chemical exergy of the continental crust is compared to the exergy of the concentrated mineral resources. The numbers obtained indicate the huge chemical exergy wealth of the crust: 6 × 10 6 Gtoe. However, this study shows that approximately only 0.01% of that amount can be effectively used by man.
Fraux, Guillaume; Coudert, François-Xavier; Boutin, Anne; Fuchs, Alain H
2017-12-07
We review the high pressure forced intrusion studies of water in hydrophobic microporous materials such as zeolites and MOFs, a field of research that has emerged some 15 years ago and is now very active. Many of these studies are aimed at investigating the possibility of using these systems as energy storage devices. A series of all-silica zeolites (zeosil) frameworks were found suitable for reversible energy storage because of their stability with respect to hydrolysis after several water intrusion-extrusion cycles. Several microporous hydrophobic zeolite imidazolate frameworks (ZIFs) also happen to be quite stable and resistant towards hydrolysis and thus seem very promising for energy storage applications. Replacing pure water by electrolyte aqueous solutions enables to increase the stored energy by a factor close to 3, on account of the high pressure shift of the intrusion transition. In addition to the fact that aqueous solutions and microporous silica materials are environmental friendly, these systems are thus becoming increasingly interesting for the design of new energy storage devices. This review also addresses the theoretical approaches and molecular simulations performed in order to better understand the experimental behavior of nano-confined water. Molecular simulation studies showed that water condensation takes place through a genuine first-order phase transition, provided that the interconnected pores structure is 3-dimensional and sufficiently open. In an extreme confinement situations such as in ferrierite zeosil, condensation seem to take place through a continuous supercritical crossing from a diluted to a dense fluid, on account of the fact that the first-order transition line is shifted to higher pressure, and the confined water critical point is correlatively shifted to lower temperature. These molecular simulation studies suggest that the most important features of the intrusion/extrusion process can be understood in terms of equilibrium
Thermodynamics in f(R,T) theory of gravity
International Nuclear Information System (INIS)
Sharif, M.; Zubair, M.
2012-01-01
A non-equilibrium picture of thermodynamics is discussed at the apparent horizon of FRW universe in f(R,T) gravity, where R is the Ricci scalar and T is the trace of the energy-momentum tensor. We take two forms of the energy-momentum tensor of dark components and demonstrate that equilibrium description of thermodynamics is not achievable in both cases. We check the validity of the first and second law of thermodynamics in this scenario. It is shown that the Friedmann equations can be expressed in the form of first law of thermodynamics T h dS' h +T h d jmath S' = −dE'+W'dV, where d jmath S' is the entropy production term. Finally, we conclude that the second law of thermodynamics holds both in phantom and non-phantom phases
Energy Technology Data Exchange (ETDEWEB)
Nagels-Silvert, V
2004-09-15
The main purpose of this thesis is to get experimental data for the testing and validation of atomic physics codes dealing with non-local-thermodynamical-equilibrium plasmas. The first part is dedicated to the spectroscopic study of xenon and krypton plasmas that have been produced by a nanosecond laser pulse interacting with a gas jet. A Thomson scattering diagnostic has allowed us to measure independently plasma parameters such as electron temperature, electron density and the average ionisation state. We have obtained time integrated spectra in the range between 5 and 10 angstroms. We have identified about one hundred xenon rays between 8.6 and 9.6 angstroms via the use of the Relac code. We have discovered unknown rays for the krypton between 5.2 and 7.5 angstroms. In a second experiment we have extended the wavelength range to the X UV domain. The Averroes/Transpec code has been tested in the ranges from 9 to 15 angstroms and from 10 to 130 angstroms, the first range has been well reproduced while the second range requires a more complex data analysis. The second part is dedicated to the spectroscopic study of aluminium, selenium and samarium plasmas in femtosecond operating rate. We have designed an interferometry diagnostic in the frequency domain that has allowed us to measure the expanding speed of the target's backside. Via the use of an adequate isothermal model this parameter has led us to know the plasma electron temperature. Spectra and emission times of various rays from the aluminium and selenium plasmas have been computed satisfactorily with the Averroes/Transpec code coupled with Film and Multif hydrodynamical codes. (A.C.)
Energy Technology Data Exchange (ETDEWEB)
Nagels-Silvert, V
2004-09-15
The main purpose of this thesis is to get experimental data for the testing and validation of atomic physics codes dealing with non-local-thermodynamical-equilibrium plasmas. The first part is dedicated to the spectroscopic study of xenon and krypton plasmas that have been produced by a nanosecond laser pulse interacting with a gas jet. A Thomson scattering diagnostic has allowed us to measure independently plasma parameters such as electron temperature, electron density and the average ionisation state. We have obtained time integrated spectra in the range between 5 and 10 angstroms. We have identified about one hundred xenon rays between 8.6 and 9.6 angstroms via the use of the Relac code. We have discovered unknown rays for the krypton between 5.2 and 7.5 angstroms. In a second experiment we have extended the wavelength range to the X UV domain. The Averroes/Transpec code has been tested in the ranges from 9 to 15 angstroms and from 10 to 130 angstroms, the first range has been well reproduced while the second range requires a more complex data analysis. The second part is dedicated to the spectroscopic study of aluminium, selenium and samarium plasmas in femtosecond operating rate. We have designed an interferometry diagnostic in the frequency domain that has allowed us to measure the expanding speed of the target's backside. Via the use of an adequate isothermal model this parameter has led us to know the plasma electron temperature. Spectra and emission times of various rays from the aluminium and selenium plasmas have been computed satisfactorily with the Averroes/Transpec code coupled with Film and Multif hydrodynamical codes. (A.C.)
Bergemann, Maria; Collet, Remo; Amarsi, Anish M.; Kovalev, Mikhail; Ruchti, Greg; Magic, Zazralt
2017-09-01
We determine Mg abundances in six Gaia benchmark stars using theoretical one-dimensional (1D) hydrostatic model atmospheres, as well as temporally and spatially averaged three-dimensional () model atmospheres. The stars cover a range of Teff from 4700 to 6500 K, log g from 1.6 to 4.4 dex, and [Fe/H] from -3.0 dex to solar. Spectrum synthesis calculations are performed in local thermodynamic equilibrium (LTE) and in non-LTE (NLTE) using the oscillator strengths recently published by Pehlivan Rhodin et al. We find that: (a) Mg abundances determined from the infrared spectra are as accurate as the optical diagnostics, (b) the NLTE effects on Mg I line strengths and abundances in this sample of stars are minor (although for a few Mg I lines the NLTE effects on abundance exceed 0.6 dex in and 0.1 dex in 1D, (c) the solar Mg abundance is 7.56+/- 0.05 dex (total error), in excellent agreement with the Mg abundance measured in CI chondritic meteorites, (d) the 1D NLTE and NLTE approaches can be used with confidence to analyze optical Mg I lines in spectra of dwarfs and sub-giants, but for red giants the Mg I 5711 Å line should be preferred, (e) low-excitation Mg I lines are sensitive to the atmospheric structure; for these lines, LTE calculations with models lead to significant systematic abundance errors. The methods developed in this work will be used to study Mg abundances of a large sample of stars in the next paper in the series.
Seasonal thermal energy storage in shallow geothermal systems: thermal equilibrium stage
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Nowamooz Hossein
2016-01-01
Full Text Available This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. The variation of temperature was obtained after 3 heating and cooling cycles for the different types of loads with maximum thermal load of qmax = 15 W.m−1 with variable angular frequency (8 months of heating and 4 months of cooling.and constant angular frequency (6 months of heating and 6 months of cooling to estimate the necessary number of cycles to reach the thermal equilibrium stage. The results show that we approach a thermal equilibrium stage where the same variation of temperature can be observed in soils after several heating and cooling cycles. Based on these simulations, the necessary number of cycles can be related to the total applied energy on the system and the minimum number of cycles is for a system with the total applied energy of 1.9qmax.
Ge, Hao; Qian, Hong
2013-06-01
Nonequilibrium thermodynamics of a system situated in a sustained environment with influx and efflux is usually treated as a subsystem in a larger, closed "universe." A question remains with regard to what the minimally required description for the surrounding of such an open driven system is so that its nonequilibrium thermodynamics can be established solely based on the internal stochastic kinetics. We provide a solution to this problem using insights from studies of molecular motors in a chemical nonequilibrium steady state (NESS) with sustained external drive through a regenerating system or in a quasisteady state (QSS) with an excess amount of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and inorganic phosphate (Pi). We introduce the key notion of minimal work that is needed, W(min), for the external regenerating system to sustain a NESS (e.g., maintaining constant concentrations of ATP, ADP and Pi for a molecular motor). Using a Markov (master-equation) description of a motor protein, we illustrate that the NESS and QSS have identical kinetics as well as the second law in terms of the same positive entropy production rate. The heat dissipation of a NESS without mechanical output is exactly the W(min). This provides a justification for introducing an ideal external regenerating system and yields a free-energy balance equation between the net free-energy input F(in) and total dissipation F(dis) in an NESS: F(in) consists of chemical input minus mechanical output; F(dis) consists of dissipative heat, i.e. the amount of useful energy becoming heat, which also equals the NESS entropy production. Furthermore, we show that for nonstationary systems, the F(dis) and F(in) correspond to the entropy production rate and housekeeping heat in stochastic thermodynamics and identify a relative entropy H as a generalized free energy. We reach a new formulation of Markovian nonequilibrium thermodynamics based on only the internal kinetic equation without further