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Статті в журналах з теми "Equilibrium thermodynamic calculations"

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Zhang, Tao, and Shuyu Sun. "Thermodynamics-Informed Neural Network (TINN) for Phase Equilibrium Calculations Considering Capillary Pressure." Energies 14, no. 22 (November 18, 2021): 7724. http://dx.doi.org/10.3390/en14227724.

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The thermodynamic properties of fluid mixtures play a crucial role in designing physically meaningful models and robust algorithms for simulating multi-component multi-phase flow in subsurface, which is needed for many subsurface applications. In this context, the equation-of-state-based flash calculation used to predict the equilibrium properties of each phase for a given fluid mixture going through phase splitting is a crucial component, and often a bottleneck, of multi-phase flow simulations. In this paper, a capillarity-wise Thermodynamics-Informed Neural Network is developed for the first time to propose a fast, accurate and robust approach calculating phase equilibrium properties for unconventional reservoirs. The trained model performs well in both phase stability tests and phase splitting calculations in a large range of reservoir conditions, which enables further multi-component multi-phase flow simulations with a strong thermodynamic basis.
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Sundman, Bo, and John Ågren. "Computer Applications in the Development of Steels." MRS Bulletin 24, no. 4 (April 1999): 32–36. http://dx.doi.org/10.1557/s0883769400052167.

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Despite the fact that thermodynamic calculations, strictly speaking, apply only to equilibrium, they may of ten be used in nonequilibrium situations. If one or several of the stable phases are suppressed in the calculations, we have a metastable equilibrium, which is often of practical interest. For example, one may calculate the driving force available to form the more stable phases and model nucleation.Thermodynamic calculations may be performed stepwise to predict microseg-regation during solidification by a Scheil-type calculation (no diffusion in the solid State, infinite diffusion in the liquid, and equilibrium at the interface). In such a calculation, no information other than the thermodynamic properties of the System is used.A more ambitious approach is to com-bine the thermodynamic calculations with kinetic modeis (e.g., diffusion calculations) and thereby predict the rate of reactions. This approach is extremely powerful and may be used to simulate a wide range of different phenomena, including precipitation, homogenization, and diffusional interactionsbetween Substrate and coating.It is usually assumed that thermodynamic equilibrium holds locally at the migrating phase interface between two phases, and the rate of transformation is calculated at each instant by solving a set of flux-balance equations. The fluxes are obtained from a numerical Solution of the multicomponent diffusion equations (see Reference 3).
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Ewing, Mark E., and Daron A. Isaac. "Thermodynamic Property Calculations for Equilibrium Mixtures." Journal of Thermophysics and Heat Transfer 32, no. 1 (January 2018): 118–28. http://dx.doi.org/10.2514/1.t5144.

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Lothenbach, Barbara. "Thermodynamic equilibrium calculations in cementitious systems." Materials and Structures 43, no. 10 (April 17, 2010): 1413–33. http://dx.doi.org/10.1617/s11527-010-9592-x.

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Belov, G. V. "Calculation of Equilibrium Composition of Complex Thermodynamic Systems using Julia Language and Ipopt Library." Herald of the Bauman Moscow State Technical University. Series Instrument Engineering, no. 3 (136) (September 2021): 24–45. http://dx.doi.org/10.18698/0236-3933-2021-3-24-45.

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The article considers the possibility of using the Ipopt optimization package for the calculating the phase and equilibrium compositions of a multicomponent heterogeneous thermodynamic system. Two functions are presented for calculating the equilibrium composition and properties of complex thermodynamic systems, written in the Julia programming language. These functions are the key ones in the program integrated with the IVTANTERMO database on thermodynamic properties of individual substances and used for conducting test calculations. The test calculations showed that Ipopt package allows determining the phase and chemical compositions of simple and complex thermodynamic systems with a fairly high speed. Using the JuMP modeling language significantly simplifies the preparation of the initial data for the Ipopt package, therefore the functions presented in this article are very compact. It is shown how the Ipopt package can be used when the temperature of the thermodynamic system is unknown. The approach proposed in this work is applicable both for analyzing the equilibrium of individual chemical reactions and for calculating the equilibrium composition of complex chemically reacting systems. The simplicity of the proposed functions allows their easy integrating into application programs, embedding them into more complex applications, using them in combination with more complex models (real gas, nonideal solutions, constrained equilibria), and, if necessary, modifying them. It should be noted that the versatility of the JuMP modeling language makes it possible to replace the Ipopt package with another one without significant modification of the program text
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Ramette, Richard W. "REACT: Exploring Practical Thermodynamic and Equilibrium Calculations." Journal of Chemical Education 72, no. 3 (March 1995): 240. http://dx.doi.org/10.1021/ed072p240.

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Földényi, Rita, and Aurél Marton. "Organisation of the Analytical, Stoichiometric, and Thermodynamic Information for water Chemistry Calculations." Hungarian Journal of Industry and Chemistry 43, no. 1 (June 1, 2015): 33–38. http://dx.doi.org/10.1515/hjic-2015-0006.

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Abstract A common feature of the chemical processes of the hydrosphere and water treatment plants is that essentially the same types of chemical equilibrium reactions occur in both fields. These equilibria could be acid/base, complexation, redox, precipitation, and interfacial processes. Since these reactions may also occur in combination, the aqueous environments are unavoidably multispecies systems. Due to multiple equilibria, the state of aggregation, the state of oxidation, as well as the electric charge of the species may change dramatically. Calculation of the equilibrium concentration of the species is facilitated by the availability of analytical, stoichiometric, and thermodynamic information that are consistently organised into an ASTI matrix. The matrix makes it possible to apply a uniform algebraic treatment for all occurring equilibria even, if later on, further reactions have to be included in the chemical model. The use of the ASTI matrix enables us to set up the necessary mass balance equations and equilibrium relationships, which together form a non-linear system of equations (NLSE). The goal of our paper is to show that the use of the ASTI matrix approach in cooperation with the powerful engineering calculation software, MATHCAD14, results in fast and easy handling of the NLSE-s and, consequently, the calculations of speciation in aqueous systems. The paper demonstrates the method of application in three examples: the calculation of the pH dependence of the solubility of calcite in closed and open systems, the calculation of the pH and pε in a system where acid/base reactions, complexation equilibria, and redox equilibria occur, and a study of adsorption of lead ions on aluminium oxide.
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Novák, Josef P., Vlastimil Růžička, Jaroslav Matouš, and Jiří Pick. "Liquid-liquid equilibrium. Computation of liquid-liquid equilibrium in terms of an equation of state." Collection of Czechoslovak Chemical Communications 51, no. 7 (1986): 1382–92. http://dx.doi.org/10.1135/cccc19861382.

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An algorithm for calculating the boiling point pressure at a chosen temperature and composition was used for computing liquid-liquid equilibrium. A lot of attention is paid to the determination of the first approximation which is specified in terms of the conditions of thermodynamic stability. The conditions of thermodynamic stability make as well possible to localize the lower and upper critical end points (LCEP and UCEP. The Redlich-Kwong-Soave equation of state was applied in calculations, and it was found out that this equation with zero interaction parameters predicts well the lower and upper critical end temperatures in the systems methane-n-hexane, ethane-n-eicosane and ethane-n-docosane.
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Pelton, A. D. "Thermodynamic databases and equilibrium calculations in metallurgical processes." Pure and Applied Chemistry 69, no. 5 (January 1, 1997): 969–78. http://dx.doi.org/10.1351/pac199769050969.

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Ze-Qing, Wu, Han Guo-Xing, and Pang Jin-Qiao. "Opacity Calculations for Non-Local Thermodynamic Equilibrium Mixtures." Chinese Physics Letters 19, no. 4 (March 26, 2002): 518–20. http://dx.doi.org/10.1088/0256-307x/19/4/321.

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Дисертації з теми "Equilibrium thermodynamic calculations"

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Zinser, Alexander [Verfasser], Kai [Gutachter] Sundmacher, and Achim [Gutachter] Kienle. "Dynamic methods for thermodynamic equilibrium calculations in process simulation and process optimization / Alexander Zinser ; Gutachter: Kai Sundmacher, Achim Kienle." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://d-nb.info/1219937207/34.

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Höglund, Andreas. "Electronic Structure Calculations of Point Defects in Semiconductors." Doctoral thesis, Uppsala universitet, Fysiska institutionen, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7926.

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In this thesis point defects in semiconductors are studied by electronic structure calculations. Results are presented for the stability and equilibrium concentrations of native defects in GaP, InP, InAs, and InSb, for the entire range of doping conditions and stoichiometry. The native defects are also studied on the (110) surfaces of InP, InAs, and InSb. Comparing the relative stability at the surface and in the bulk, it is concluded that the defects have a tendency to migrate to the surface. It is found that the cation vacancy is not stable, but decomposes into an anion antisite-anion vacancy complex. The surface charge accumulation in InAs is explained by complementary intrinsic doping by native defects and extrinsic doping by residual hydrogen. A technical investigation of the supercell treatment of defects is performed, testing existing correction schemes and suggesting a more reliable alternative. It is shown that the defect level of [2VCu-IIICu] in the solarcell-material CuIn1-xGaxSe2 leads to a smaller band gap of the ordered defect γ-phase, which possibly explains why the maximal efficiency for CuIn1-xGaxSe2 has been found for x=0.3 and not for x=0.6, as expected from the band gap of the α-phase. It is found that Zn diffuses via the kick-out mechanism in InP and GaP with activation energies of 1.60 eV and 2.49 eV, respectively. Explanations are found for the tendency of Zn to accumulate at pn-junctions in InP and to why a relatively low fraction of Zn is found on substitutional sites in InP. Finally, it is shown that the equilibrium solubility of dopants in semiconductors can be increased significantly by strategic alloying. This is shown to be due to the local stress in the material, and the solubility in an alloy can in fact be much higher than in either of the constituting elements. The equilibrium solubility of Zn in Ga0.9In0.1P is for example five orders of magnitude larger than in GaP or InP.
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Belsito, Danielle L. "Application of Computational Thermodynamic and Solidification Kinetics to Cold Sprayable Powder Alloy Design." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-dissertations/28.

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Military aircraft that require high maneuverability, durability, ballistic protection, reparability, and energy efficiency require structural alloys with low density, high toughness, and high strength. Also, repairs to these aircraft demand a production process that has the flexibility to be relatively in-situ with the same high-performance output. Materials produced by the cold spray process, a thermo-mechanical powder consolidation technique, meet many of the requirements. In accordance with President Obama’s 2011 Materials Genome Initiative, the focus of this effort is to design customized aluminum alloy powders which exploit the unique behavior and properties of the materials created by the cold spray process. Analytical and computational models are used to customize microchemistry, thermal conditioning, and solidification behavior of the powders by predicting equilibrium and non-equilibrium microstructure and resulting materials properties and performance. Thermodynamic, kinetic, and solidification models are used, including commercial software packages Thermo-Calc, Pandat™, and JMatPro®, and TC-PRISMA. Predicted powder properties can be used as input into a cold spray process impact model to determine the consolidated materials’ properties. Mechanical properties of powder particles are predicted as a function of powder particle diameter and are compared to experimental results.
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Lundholm, Karin. "Fate of Cu, Cr, As and some other trace elements during combustion of recovered waste fuels." Doctoral thesis, Umeå : Department of Applied Physics and Electronics, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1132.

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Bratberg, Johan. "Phase equilibria and thermodynamic properties of high-alloy tool steels : theoretical and experimental approach." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-453.

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Yamada, Ryo. "Application of Steepest-Entropy-Ascent Quantum Thermodynamics to Solid-State Phenomena." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85866.

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Steepest-entropy-ascent quantum thermodynamics (SEAQT) is a mathematical and theoretical framework for intrinsic quantum thermodynamics (IQT), a unified theory of quantum mechanics and thermodynamics. In the theoretical framework, entropy is viewed as a measure of energy load sharing among available energy eigenlevels, and a unique relaxation path of a system from an initial non-equilibrium state to a stable equilibrium is determined from the greatest entropy generation viewpoint. The SEAQT modeling has seen a great development recently. However, the applications have mainly focused on gas phases, where a simple energy eigenstructure (a set of energy eigenlevels) can be constructed from appropriate quantum models by assuming that gas-particles behave independently. The focus of this research is to extend the applicability to solid phases, where interactions between constituent particles play a definitive role in their properties so that an energy eigenstructure becomes quite complicated and intractable from quantum models. To cope with the problem, a highly simplified energy eigenstructure (so-called ``pseudo-eigenstructure") of a condensed matter is constructed using a reduced-order method, where quantum models are replaced by typical solid-state models. The details of the approach are given and the method is applied to make kinetic predictions in various solid-state phenomena: the thermal expansion of silver, the magnetization of iron, and the continuous/discontinuous phase separation and ordering in binary alloys where a pseudo-eigenstructure is constructed using atomic/spin coupled oscillators or a mean-field approximation. In each application, the reliability of the approach is confirmed and the time-evolution processes are tracked from different initial states under varying conditions (including interactions with a heat reservoir and external magnetic field) using the SEAQT equation of motion derived for each specific application. Specifically, the SEAQT framework with a pseudo-eigenstructure successfully predicts: (i) lattice relaxations in any temperature range while accounting explicitly for anharmonic effects, (ii) low-temperature spin relaxations with fundamental descriptions of non-equilibrium temperature and magnetic field strength, and (iii) continuous and discontinuous mechanisms as well as concurrent ordering and phase separation mechanisms during the decomposition of solid-solutions.
Ph. D.
Many engineering materials have physical and chemical properties that change with time. The tendency of materials to change is quantified by the field of thermodynamics. The first and second laws of thermodynamics establish conditions under which a material has no tendency to change; these conditions are called equilibrium states. When a material is not in an equilibrium state, it is able to change spontaneously. Classical thermodynamics reliably identifies whether a material is susceptible to change, but it is incapable of predicting how change will take place or how fast it will occur. These are kinetic questions that fall outside the purview of thermodynamics. A relatively new theoretical treatment developed by Hatsopoulos, Gyftopoulos, Beretta and others over the past forty years extends classical thermodynamics into the kinetic realm. This framework, called steepest-entropy-ascent quantum thermodynamics (SEAQT), combines the tools of thermodynamics with quantum mechanics through a postulated equation of motion. Solving the equation of motion provides a kinetic description of the path a material will take as it changes from a non-equilibrium state to stable equilibrium. To date, the SEAQT framework has been applied primarily to systems of gases. In this dissertation, solid-state models are employed to extend the SEAQT approach to solid materials. The SEAQT framework is used to predict the thermal expansion of silver, the magnetization of iron, and the kinetics of atomic clustering and ordering in binary solid-solutions as a function of time or temperature. The model makes it possible to predict a unique kinetic path from any arbitrary, non-equilibrium, initial state to a stable equilibrium state. In each application, the approach is tested against experimental data. In addition to reproducing the qualitative kinetic trends in the cases considered, the SEAQT framework shows promise for modeling the behavior of materials far from equilibrium.
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Razavi, Seyed Mostafa. "OPTIMIZATION OF A TRANSFERABLE SHIFTED FORCE FIELD FOR INTERFACES AND INHOMOGENEOUS FLUIDS USING THERMODYNAMIC INTEGRATION." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1481881698375321.

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Maghsoodloobabakhani, Saheb. "Cristallisation à l'équilibre et hors équilibre d'hydrates mixtes de gaz : Mesures PVTx et modélisation thermodynamique." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEM027.

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Dans ce travail, afin d'étudier la formation à l’équilibre et hors équilibre des hydrates mixtes de gaz, deux procédures de formation, rapide et lente, ont été appliqué à des mélanges de CH4-C2H6-C3H8-nC4H10-CO2-N2. L'objectif de ces deux procédures est d'examiner les effets cinétiques de la vitesse de cristallisation sur l'état final, soit dans des conditions dynamiques habituelles (formation rapide) soit en régime permanent (formation lente). Contrairement à la plupart des données de la littérature, qui fournissent uniquement des données de température-pression-composition gaz (PTy), cette étude fournit également la composition, le volume, la capacité de stockage, la densité de la phase hydrate, ou encore le nombre d'hydratation et la conversion d'eau. Les résultats montrent que, lors d'une cristallisation rapide, le volume d'hydrate augmente de 2% à 69% selon le mélange gazeux. De plus, la capacité de stockage diminue avec l'augmentation de la vitesse de cristallisation. En outre, un modèle thermodynamique, basé sur la méthode classique de van der Waals et Platteuw avec le potentiel de Kihara, a été utilisé. Un nouvel ensemble de paramètres Kihara pour le propane, basé sur une cristallisation lente, a été obtenu avec succès et comparé à la littérature. Les données sur la phase hydrates étant rares dans la littérature, ces dernières ont été collectées, et comparé au modèle thermodynamique précédent. Cela permet de mettre en évidence la capacité de la simulation à prédire la composition de la phase hydrate. Bien que ces outils soient intéressants pour prédire les équilibres de phase des molécules légères, ils deviennent moins fiables lorsque des transitions de phase se produisent (coexistence de structures) ou lorsque des molécules plus lourdes sont impliquées. Une analyse par spectroscopie RAMAN a d’ailleurs mis en évidence la coexistence de structures I et II pour un gaz riche en CO2 à partir d’un mélange CO2/C3H8. Pour conclure, la vitesse de cristallisation influence significativement le procédé de formation d’un hydrate mixte. L’utilisation d’un flash thermodynamique, combinant thermodynamique et bilan de masse, montre bien qu’une cristallisation lente est nécessaire pour satisfaire l’équilibre thermodynamique, et donc augmenter la capacité de stockage, et optimiser les procédés hydrate
In this work, in order to investigate the non-equilibrium behaviors of mixed clathrate hydrates, vapor-liquid-hydrate phase equilibria of mixed gas hydrates from CH4-C2H6-C3H8-nC4H10-CO2-N2 are studied. Two different experimental procedures are used: at quick and slow crystallization rates. The aim is to examine the effects of crystallization rate on the final state, either under usual dynamic (quick formation) or steady state conditions (slow formation). Unlike most of the literature data, providing temperature-pressure-vapor composition (PTy) results, this study also furnishes hydrate composition, volume, storage capacity, density, or hydration number and water conversion. At quick crystallization, hydrate volume increases from 2% to 69% according to the gas mixture. Moreover, storage capacity decreases with increasing rate of crystallization. In addition, a thermodynamic model, based on classical van der Waals and Platteuw method and Kihara potential, has been used. A new set of Kihara parameters for propane, based on slow crystallization, has been obtained successfully and compared to the literature.Besides, a review on guest composition in hydrates from experimental results is suggested, based on open literature. Then, the capability of thermodynamic modeling to simulate these rare data has been investigated. While simulation tools are interesting to predict phase equilibria for light molecules, they become less reliable when phase transition occurs in the system, or when heavier molecules are involved. In addition, the use of RAMAN spectroscopy has illustrated phase transition for CO2/C3H8 mixed hydrates under CO2 rich gas conditions.To conclude, the rate of crystallization significantly influences the process of mixed hydrates formation. The use of a thermodynamic flash shows that slow crystallization is necessary to satisfy the thermodynamic equilibrium, and thus increase storage capacity, and optimize hydrate processes
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Ammar, Mohamed Naceur. "Modélisation d'opérations unitaires et méthodes numériques de calcul d'équilibre liquide-vapeur." ENMP, 1986. http://www.theses.fr/1986ENMP0002.

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Application du logiciel aspen plus du mit au calcul des equilibres entre phases des systemes eau-hydrocarbures, et a l'optimisation d'une operation de lavage (exemple sur le charbon). On traite aussi de nouveaux calculs pour l'analyse de la stabilite thermodynamique de systemes complexes
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Le, Quang-Du. "Investigation de la cristallisation hors-équilibre des clathrates hydrates de gaz mixtes : une étude expérimentale comparée à la modélisation thermodynamique avec et sans calculs flash." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEM002/document.

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L’activité scientifique du sujet porte sur l’acquisition de données expérimentales et la modélisation de la composition des clathrates hydrates de gaz. Les domaines d’application concernent la séparation et le stockage de gaz, la purification de l’eau, et le stockage d’énergie par matériaux à changement de phase.L’équipe a mis en évidence il y a quelques années que la composition des hydrates de gaz était sensible aux conditions de cristallisation, et que le phénomène de formation se produisait en dehors de l’équilibre thermodynamique.Le travail de thèse a permis d’explorer plusieurs modes de cristallisation à partir de solutions de même composition initiale pour observer les différences concernant l’état final, compositions notamment, et les relier à la vitesse de cristallisation. Suivant le mode de cristallisation, lent ou rapide, l’acquisition des données expérimentales peut prendre de quelques jours à plusieurs semaines. Les expériences sont réalisées en réacteur pressurisé dans lequel nous mesurons en ligne la composition de la phase gaz et de la phase liquide, pour calculer par bilan de matière la composition de la phase hydrate.Nous avons bien mis en évidence des variations dans la composition de la phase hydrate suivant le mode de cristallisation. Nous avons dû établir un modèle thermodynamique donnant la composition de la phase hydrate à l’équilibre pour des mélanges de gaz qui n’avaient jamais été traité par la littérature, et qui ont donc nécessité des campagnes de mesure extrêmement lentes et donc longues pour être sûr de l’état thermodynamique à l’équilibre.Nous sommes en cours d’établir un modèle cinétique pour modéliser les écarts à cet état d’équilibre de référence pour nos expériences réalisées à vitesse de cristallisation rapide
The scientific goal of this thesis is based on the acquisition of experimental data and the modeling of the composition of clathrates gas hydrate. The domains of application concern the gas separation and storage, water purification, and energy storage using change phase materials (PCMs).Our research team has recently demonstrated that the composition of gas hydrates was sensitive to the crystallization conditions, and that the phenomenon of formation was out of thermodynamic equilibrium. During this thesis, we have investigated several types of crystallization, which are based on the same initial states. The goal is to point out the differences between the initial solution composition and the final solution composition, and to establish a link between the final state and the crystallization rate.Depending on the rate of crystallization (slow or fast), the acquisition time of experimental data lasted from a few days to several weeks. The experimental tests were performed inside a stirred batch reactor (autoclave, 2.44 or 2.36 L) cooled with a double jacket. Real-time measurements of the composition of the gas and the liquid phases have been performed, in order to calculate the composition of the hydrate phase using mass balance calculations. Depending on the crystallization mode, we have identified several variations of the composition of the hydrate phase and final hydrate volume.We have established a successful thermodynamic model, which indicates the composition of the hydrate phase and hydrate volume in thermodynamic equilibrium state using a gas mixture which had never been used before in the literature. So this thermodynamic model has required an extremely slow experimental test. These tests were also long in order to be sure of the thermodynamic equilibrium state.We are currently establishing a kinetics model in order to model the deviations from the reference point of equilibrium of our experimental tests which were carried out at a high crystallization rate
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Книги з теми "Equilibrium thermodynamic calculations"

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1940-, Sandler Stanley I., ed. Models for thermodynamic and phase equilibria calculations. New York: Dekker, 1994.

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2

Gupta, Roop N. Calculations and curve fits of thermodynamic and transport properties for equilibrium air to 30000 K. Hampton, Va: Langley Research Center, 1991.

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3

Gordon, Sanford. Computer program for calculation of complex chemical equilibrium compositions and applications. [Washington, D.C.]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1994.

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Gordon, Sanford. Computer program for calculation of complex chemical equilibrium compositions and applications. [Cleveland, Ohio]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1996.

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5

Gordon, Sanford. Computer program for calculation of complex chemical equilibrium compositions and applications. Washington, D.C: NASA, 1994.

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6

Calculations and curve fits of thermodynamic and transport properties for equilibrium air to 30 000 K. Washington, D.C: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.

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7

N, Gupta Roop, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Program., eds. Calculations and curve fits of thermodynamic and transport properties for equilibrium air to 30 000 K. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Program, 1991.

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8

Currier, Robert Patrick. A statistical mechanical group contribution method for calculating thermodynamic properties of fluids. 1987.

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9

Electrical Installation Calculations: For Compliance with BS 7671. Blackwell Science Inc, 1998.

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10

Allen, Michael P., and Dominic J. Tildesley. How to analyse the results. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198803195.003.0008.

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In this chapter, practical guidance is given on the calculation of thermodynamic, structural, and dynamical quantities from simulation trajectories. Program examples are provided to illustrate the calculation of the radial distribution function and a time correlation function using the direct and fast Fourier transform methods. There is a detailed discussion of the calculation of statistical errors through the statistical inefficiency. The estimation of the error in equilibrium averages, fluctuations and in time correlation functions is discussed. The correction of thermodynamic averages to neighbouring state points is described along with the extension and extrapolation of the radial distribution function. The calculation of transport coefficients by the integration of the time correlation function and through the Einstein relation is discussed.
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Частини книг з теми "Equilibrium thermodynamic calculations"

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Chen, Long-Qing. "Thermodynamic Calculations of Materials Processes." In Thermodynamic Equilibrium and Stability of Materials, 175–239. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-13-8691-6_8.

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Stateva, Roumiana P., and Georgi St Cholakov. "Challenges in the Modeling of Thermodynamic Properties and Phase Equilibrium Calculations for Biofuels Process Design." In Process Systems Engineering for Biofuels Development, 85–120. Chichester, UK: John Wiley & Sons, Ltd, 2020. http://dx.doi.org/10.1002/9781119582694.ch4.

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Bharti, Anand, Debashis Kundu, Dharamashi Rabari, and Tamal Banerjee. "COSMO-SAC: A Predictive Model for Calculating Thermodynamic Properties on a-priori Basis." In Phase Equilibria in Ionic Liquid Facilitated Liquid–Liquid Extractions, 53–90. Boca Raton, FL : CRC Press, Taylor & Francis Group, [2017]: CRC Press, 2017. http://dx.doi.org/10.1201/9781315367163-3.

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4

Riyahi Malayeri, Kamrooz, Patrik Ölund, and Ulf Sjöblom. "Thermodynamic Calculations Versus Instrumental Analysis of Slag-Steel Equilibria in an ASEA–SKF Ladle Furnace." In Bearing Steel Technologies: 10th Volume, Advances in Steel Technologies for Rolling Bearings, 1–11. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2014. http://dx.doi.org/10.1520/stp158020140025.

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"Chapter 11 | Chemical Equilibrium Calculations." In The ASTM Computer Program for Chemical Thermodynamic and Energy Release Evaluation - Chetah® Version 11.0, 77–84. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2020. http://dx.doi.org/10.1520/ds51hol20200011.

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Bokstein, Boris S., Mikhail I. Mendelev, and David J. Srolovitz. "Basic laws of thermodynamics." In Thermodynamics and Kinetics in Materials Science. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780198528036.003.0003.

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In this chapter, we first introduce the basic laws of thermodynamics and R17the most important thermodynamic functions. Even though many of the concepts introduced here will be familiar to many readers with a background in elementary physics, this chapter should not be ignored as it presents these concepts in the language of physical chemistry. Since these concepts form the basis of physical chemistry, this subject will make no sense without a firm footing in these fundamentals. Thermodynamics focuses on the thermal behavior of macroscopic systems (i.e. systems containing a very large number of particles). Thermal processes include both heat exchange between a system and its surroundings and work. The general scheme of a thermodynamic description of such processes can be described as in the picture: Thermodynamic descriptions are usually based upon experimental observations. Experiments can characterize the thermodynamic state of the system in terms of a small number of measurable parameters (e.g. temperature T and pressure p). The generalization of these measurements yields thermodynamics laws. Thermodynamic laws identify state functions that describe the system behavior solely in terms of the system parameters and not on how the system came to be in a particular state. Changes in the state functions during some process depend on only the intial and final states of the system but not on the path between them. Therefore, these changes can be determined from calculations based on a very small set of data. Thermodynamics can be used to answer such questions as (1) is a particular process possible? (2) can the system spontaneously evolve in a particular direction?, and (3) what is the final or equilibrium state? all under a given set of conditions. Equilibrium can be understood as the state in which the system parameters no longer evolve, there are no fluxes of matter or energy through the system, and for which all small disturbances decay. According to the zeroeth law of thermodynamics any isolated system will eventually evolve to an equilibrium state and will never spontaneously leave this state (without a substantial external disturbance).
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COTTERMAN, R. L., and J. M. PRAUSNITZ. "CONTINUOUS THERMODYNAMICS FOR PHASE-EQUILIBRIUM CALCULATIONS IN CHEMICAL PROCESS DESIGN." In Kinetic and Thermodynamic Lumping of Multicomponent Mixtures, 229–75. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-444-89032-0.50015-3.

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Doraiswamy, L. K. "Rates and Equilibria in Organic Reactions : The Thermodynamic and Extrathermodynamic Approaches." In Organic Synthesis Engineering. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195096897.003.0007.

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In any reversible reaction such as . . . vA A + vB B ↔ vR R + vS S [2.1] . . . the system inevitably moves toward a state of equilibrium, or maximum probability. This equilibrium state is very important in analyzing chemical reactions because it defines the limit to which any reaction can proceed. Organic reactions, particularly those constituting a synthetic scheme for a fine chemical, usually involve molecules reacting in the liquid phase. The effects of reactant structure and of the solvent (medium) in which the reaction occurs (the solvation effects) are not included in the conventional macroscopic approach to thermodynamics. Therefore, the treatment of liquid-phase reactions tends to be less exact than that of gas-phase reactions involving simpler molecules without these influences. A convenient way of approaching this problem is to start with the conventional macroscopic or thermodynamic approach and add enough microscopic detail to allow for the effects of solute (reactant) structure and the medium. This approach is called the extrathermodynamic approach and may be regarded as bridging the gap between the two rather disparate fields of rates and equilibria represented by kinetics and thermodynamics, respectively. Such an approach is particularly useful in organic synthesis and forms the subject matter of this chapter. An important consideration in process calculations is the change that results in the basic thermodynamic properties, internal energy (U), enthalpy (H), Helmholtz work function (A), and Gibbs free energy (G) when a closed system of constant mass moves from one macroscopic state to another. For a homogeneous fluid, these change equations can be expressed in terms of four differential equations, which then can be written in difference form by employing the operator Δ to represent the change from state 1 to state 2: Of these, the enthalpy and free energy change equations are the most frequently used in the analysis of reactions.
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Gaganis, Vassilis. "Perturbation Theory and Phase Behavior Calculations Using Equation of State Models." In Perturbation Theory [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.93736.

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Equations of State (EoS) live at the heart of all thermodynamic calculations in chemical engineering applications as they allow for the determination of all related fluid properties such as vapor pressure, density, enthalpy, specific heat, and speed of sound, in an accurate and consistent way. Both macroscopic EoS models such as the classic cubic EoS models as well as models based on statistical mechanics and developed by means of perturbation theory are available. Under suitable pressure and temperature conditions, fluids of known composition may split in more than one phases, usually vapor and liquid while solids may also be present, each one exhibiting its own composition. Therefore, computational methods are utilized to calculate the number and the composition of the equilibrium phases at which a feed composition will potentially split so as to estimate their thermodynamic properties by means of the EoS. This chapter focuses on two of the most pronounced EoS models, the cubic ones and those based on statistical mechanics incorporating perturbation analysis. Subsequently, it describes the existing algorithms to solve phase behavior problems that rely on the classic rigorous thermodynamics context as well as modern trends that aim at accelerating computations.
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Schlijper, A. G., and A. R. D. van Bergen. "A FREE ENERGY CRITERION FOR THE SELECTION OF PSEUDOCOMPONENTS FOR VAPOUR/LIQUID EQUILIBRIUM CALCULATIONS." In Kinetic and Thermodynamic Lumping of Multicomponent Mixtures, 293–305. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-444-89032-0.50017-7.

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Тези доповідей конференцій з теми "Equilibrium thermodynamic calculations"

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Hurley, C. D., M. Whiteman, and C. W. Wilson. "The Calculation of Thermodynamic Non Equilibrium Combustion Product Compositions." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-275.

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A method is presented by which the product composition and temperature of constant pressure combustion reactions can be calculated for non equilibrium conditions, by constraining the products free energy and entropy. The calculations for a hydrogen/ oxygen system are compared with chemical kinetic predictions. From the calculated compositions the relationship between free energy and extent of reaction are derived and thence how the individual product mole fractions vary with extent of reaction. The application of these techniques to modelling combustion chemistry is discussed.
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Zimmer, A. T., and P. Biswas. "336. Thermodynamic Equilibrium Calculations as an Occupational Assessment Tool: Welding Alloy Examples." In AIHce 1998. AIHA, 1999. http://dx.doi.org/10.3320/1.2762736.

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3

Zhao, Baofeng, Li Sun, Xiaodong Zhang, Lei Chen, Jie Zhang, Guangfan Meng, and Xiangmei Meng. "Thermodynamic Equilibrium Analysis of Rice Husk Pyrolysis." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51052.

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Pyrolysis of biomass materials can implement the efficient conversion of biomass to gaseous, liquid and solid energy products. Compared with experimental research which needs massive apparatus and funds and also takes long time, the computer simulation of biomass pyrolysis is more convenient and flexible to achieve the main characteristics of the process. Simulation of thermodynamic equilibrium for the pyrolysis of rice husk was studied in this paper. Based on the minimization of Gibbs free energy, MATLAB was used to calculate thermodynamic equilibrium for the pyrolysis of rice husk in the temperatures ranges from 523 K to 1723 K at intervals of 100 K. The results showed that the contents of H2 and CO increased rapidly with the temperature from 723 K to 1223 K, while the contents of H2O, CH4, CO2 and C decreased sharply. When the temperature was higher than 1223 K, the yields of H2 and CO reached the maximum of 51 mol% and 48 mol% respectively, and then kept stable. In order to be closer to experimental results, the constrain conditions of element C in tar was introduced in the calculations. The results indicated that, in the main components of tar from 523 K to 1223 K, the contents of naphthalene and toluene both decreased and then toluene vanished gradually. However, the content of benzene increased with increasing temperature and finally became the dominant product when the temperature was above 1300 K.
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Hosokawa, Yoshifumi. "Models for chloride ion bindings in hardened cement paste using thermodynamic equilibrium calculations." In 2nd International RILEM Symposium on Advances in Concrete through Science and Engineering. RILEM Publications, 2006. http://dx.doi.org/10.1617/2351580028.025.

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Paolini, Christopher P., and Subrata Bhattacharjee. "The IGE Model: An Extension of the Ideal Gas Model to Include Chemical Composition as Part of the Equilibrium State." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40762.

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The TEST (The Expert System for Thermodynamics, www.thermofluids.net) web portal is a comprehensive thermodynamic courseware consisting of multimedia problems and examples, an online solution manual for educators, traditional thermodynamic charts and tables, fifteen chapters of animations to illustrate thermodynamic systems and fundamental concepts, and a suite of thermodynamic calculators called daemons for evaluating thermodynamic properties and analyzing thermodynamic problems.. The state module offers Java applets for evaluation of thermodynamic states of different working substances grouped into several material models according to underlying assumptions. Gas mixtures are modeled by the perfect gas (PG) or ideal gas (IG) mixture models. In this work, we extend the IG model mixture model into an ideal gas equilibrium (IGE) mixture model by incorporating chemical equilibrium calculations as part of the state evaluation process. Through a simple graphical interface users can set the atomic composition of a gas mixture. In the state panel, the known thermodynamic properties are entered. For a given pressure and temperature, the mixture’s Gibbs function is minimized subject to atomic constraints and the equilibrium composition along with thermodynamic properties of the mixture are calculated and displayed. What is unique about this approach is that equilibrium computations are performed in the background, without requiring any major change in the familiar user interface used in other state daemons. Properties calculated by this equilibrium state daemon are compared with results from other established applications such as NASA CEA and STANJAN. Also, two different algorithms, an iterative approach and a direct approach based on minimizing different thermodynamic functions in different situation are compared.
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Depraz, Se´bastien, Philippe Rivie`re, Marie-Yvonne Perrin, and Anouar Soufiani. "Band Models for Radiative Transfer in Non-LTE Diatomic Molecules of CO2-N2 Plasmas." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22301.

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A statistical narrow-band model is developed for the optically non-thin electronic systems of carbonaceous molecules in CO2-N2 plasmas and its accuracy is studied under equilibrium and non-equilibrium conditions. Line by line calculations are used to produce curves of growth of transmissivities from which band model parameters are calculated by least-square adjustments. The model is shown to provide quite accurate description of radiative properties and radiative intensities for Doppler, Lorentz, and Voigt line profiles, and for both local thermodynamic equilibrium and a multi-temperature description of the gas mixture thermodynamic state. The model is also suitable for a more general description of the gas thermodynamic state where the electronic state populations are arbitrary.
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Kermani, Mohammad J., and Andrew G. Gerber. "Thermodynamic and Aerodynamic Loss Evaluation of Supersonic Nucleating Steam With Shocks." In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31087.

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Near saturation steam undergoing rapid expansion is numerically studied in a series of converging diverging nozzles with and without shocks. A detailed examination of the aerodynamic and thermodynamic losses are performed for thermodynamic non-equilibrium conditions. The calculations rely on a new numerical model, previously reported, for non-equilibrium phase change with droplet nucleation. In a systematic approach, the model results are first validated versus experimentally available data and then applied to more general flow situations to assess loss mechanisms. The results indicate that for weak normal shocks situated just downstream of the nozzles throat, the aerodynamic and thermodynamic losses are roughly equivalent. As the back pressure is reduced (i.e. shocks become stronger) the aerodynamic component rapidly becomes the predominant loss mechanism. The thermodynamic loss, associated with heat transfer between the phases, increases only gradually with shock strength. This gradual increase starts from a base level of loss originating with the initial nucleation of moisture, which has a strength and location independent of back pressure.
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Korotkikh, A., and I. Sorokin. "EFFECT OF BORON ON THE COMBUSTION CHARACTERISTICS OF METALLIZED HIGH-ENERGY MATERIALS." In 9TH INTERNATIONAL SYMPOSIUM ON NONEQUILIBRIUM PROCESSES, PLASMA, COMBUSTION, AND ATMOSPHERIC PHENOMENA. TORUS PRESS, 2020. http://dx.doi.org/10.30826/nepcap9a-31.

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The paper presents the results of thermodynamic calculations of the effect of pure boron additives on combustion characteristics of high-energy materials (HEM) based on ammonium perchlorate, ammonium nitrate, active fuel-binder, and powders of aluminum Al, titanium Ti, magnesium Mg, and boron B. The combustion parameters and the equilibrium composition of condensed combustion products (CCPs) of HEM model compositions were obtained with thermodynamic calculation program “Terra.” The compositions of solid propellants with different ratios of metals (Al/B, Ti/B, Mg/B, and Al/Mg/B) were considered. The combustion temperature Tad in a combustion chamber, the vacuum specific impulse J at the nozzle exit, and the mass fraction ma of the CCPs for HEMs were determined.
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Wu, Bei, and Hui Zhang. "Vapor Transport Controlled Process Models for AlN Bulk Sublimation Growth." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56564.

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Sublimation vapor transport method is a widely used technique for the production of optoelectronic materials, such as AlN single crystals. Inductively heated method is most commonly used in high temperature materials processing. In the literature, a one-step reaction with two vapor species, i.e. aluminum (Al) vapor and nitrogen (N2) gas, is usually assumed and a diffusion-controlled growth mechanism is used with thermodynamic equilibrium calculations. In the growth experiments, crystal growth may be in the kinetic controlled region, the interplay between surface kinetics and vapor transport is important. Temperature field with inductively heated method will be simulated in this paper. Afterwards, three growth models are proposed. One model is called the traditional model assuming thermodynamic equilibrium and diffusion as the rate-limiting process, and two other models are developed based on equilibrium partial pressure of either aluminum vapor or reaction nitrogen gas. The predicted growth rates by three models are compared. The advantage and disadvantage of different models are discussed.
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Kallner, Per, Anders Nordin, and Rainer Backman. "Fate of Ash Forming Elements in Gas Turbine Combustion of Pulverized Wood: Chemical Equilibrium Model Calculations." In ASME 1996 Turbo Asia Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-ta-025.

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A new concept for direct combustion of wood in a gas turbine is presently developed and tested in Sweden. The process is based on a fuel rich cyclone gasifier/separator and a direct coupled modified standard gas turbine combustor. A main concern is the behaviour of ash forming elements in the turbine. A picture of this can be obtained with chemical equilibrium calculations. The objective of the present work was to determine the equilibrium speciation of the ash forming elements from wood passing through the turbine of a gas turbine engine for varying feed characteristics and operating conditions. In addition, the differences between using only stoichiometric and using non-ideal solution models as thermodynamic input data were illustrated. The equilibrium relationships at the turbine stage were evaluated in a parametric study, utilizing statistical experimental designs to systematically perform the model calculations. A wide range of operating conditions, wood compositions and cyclone elemental retention efficiencies were thereby covered. The results show considerable variation in the alkali speciation as well as in devolitalization and condensation temperatures, depending on the elemental composition. Plots of the effects of the most influential variables are presented and results not directly displayed in this work are illustrated with model equations provided.
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Звіти організацій з теми "Equilibrium thermodynamic calculations"

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Kotlar, Anthony J. The Proper Interpretation of the Internal Energy of Formation Used in Thermodynamic Equilibrium Calculations. Fort Belvoir, VA: Defense Technical Information Center, July 1992. http://dx.doi.org/10.21236/ada252369.

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Crowley, David, Yitzhak Hadar, and Yona Chen. Rhizosphere Ecology of Plant-Beneficial Microorganisms. United States Department of Agriculture, February 2000. http://dx.doi.org/10.32747/2000.7695843.bard.

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Rhizoferrin, a siderophore produced by Rhizopus arrhizus, has been shown in previous studies to be an outstanding Fe carrier to plants. However, calculations based on stability constants and thermodynamic equilibrium lead to contradicting conclusions. In this study a kinetic approach was employed to elucidate this apparent contradiction and to determine the behavior of rhizoferrin under conditions representing soil and nutrient solutions. Stability of Fe3+ complexes in nutrient solution, rate of metal exchange with Ca, and rate of Fe extraction by the free ligand were monitored for rhizoferrin and other chelating agents by 55Fe labeling. Ferric complexes of rhizoferrin, desferri-ferrioxamine-B (DFOB), and ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA) were found to be stable in nutrient solution at pH 7.5 for 31 days, while ferric complexes of ethylenediaminetetraacetic acid (EDTA) and mugineic acid (MA) lost 50% of the chelated Fe within 2 days. Fe-Ca exchange in Ca solutions at pH 8.7 revealed rhizoferrin to hold Fe at non-equilibrium state for 3-4 weeks at 3.3 mM Ca and for longer periods at lower Ca concentrations. EDTA lost the ferric ion at a faster rate under the same conditions. Fe extraction from freshly prepared Fe-hydroxide at pH 8.7 and with 3.2 mM Ca was slow and followed the order. DFOB > EDDHA > MA > rhizoferrin > EDTA. Based on these results we suggest that a kinetic rather than equilibrium approach should be the basis for predictions of Fe-chelates efficiency. We conclude that the non-equilibrium state of rhizoferrin is of crucial importance for its behavior as a Fe carrier to plants.
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Trowbridge, L. D., and J. M. Leitnaker. SOLGAS refined: A computerized thermodynamic equilibrium calculation tool. Office of Scientific and Technical Information (OSTI), November 1993. http://dx.doi.org/10.2172/10137601.

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4

Terah, E. I. Practical classes in general chemistry for students of specialties «General Medicine», «Pediatrics», «Dentistry». SIB-Expertise, April 2022. http://dx.doi.org/10.12731/er0556.13042022.

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Videos of 11 practical lessons on general chemistry are presented. The following topics are considered – chemical thermodynamics and kinetics, chemical equilibrium, methods of expressing the concentration of solutions, electrolyte solutions, pH, buffer solutions, hydrolysis, redox pro-cesses. For each topic, the main theoretical provisions are given, as well as a detailed solution of typical calculation problems is given. The total dura-tion of the video lessons is 8 hours 21 minutes.
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Trowbridge, L. D., and J. M. Leitnaker. A spreadsheet-coupled SOLGAS: A computerized thermodynamic equilibrium calculation tool. Revision 1. Office of Scientific and Technical Information (OSTI), July 1995. http://dx.doi.org/10.2172/106516.

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