Gibbs free energy of formation of UPb s compound. Liquid lead and lead-bismuth eutectic LBE are being explored as primary candidates for coolants in accelerator driven systems and in advanced nuclear reactors due to their favorable thermo-physical and chemical properties. However, corrosion of structural materials i. The interactions of liquid lead or LBE with clad and fuel is of great scientific and technological importance in the development of advanced nuclear reactors.

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Gibbs free energy of formation of UPb s compound. Liquid lead and lead-bismuth eutectic LBE are being explored as primary candidates for coolants in accelerator driven systems and in advanced nuclear reactors due to their favorable thermo-physical and chemical properties. However, corrosion of structural materials i.

The interactions of liquid lead or LBE with clad and fuel is of great scientific and technological importance in the development of advanced nuclear reactors. The paper deals with the determination of Gibbs free energy of formation of U-rich phase i. UPb in Pb-U system, employing Knudsen effusion mass loss technique. Gibbs free energy of formation of liquid lanthanide-bismuth alloys. The calculated Gibbs free energy values are well agreed with experimental data. Estimates of Gibbs free energies of formation of chlorinated aliphatic compounds.

The Gibbs free energy of formation of chlorinated aliphatic compounds was estimated with Mavrovouniotis' group contribution method. The group contribution of chlorine was estimated from the scarce data available on chlorinated aliphatics in the literature, and found to vary somewhat according to the. Gibbs free energy of formation of lanthanum rhodate by quadrupole mass spectrometer.

The ternary oxide in the system La-Rh-O is of considerable importance because of its application in catalysis. Phase equilibria in the pseudo-binary system La 2 O 3 -Rh 2 O 3 has been investigated by Shevyakov et. Gibbs free energy of LaRhO 3 s was determined by Jacob et. No other thermodynamic data were available in the literature. Hence it was decided to determine Gibbs free energy of formation of LaRhO 3 s by an independent technique, viz.

Directory of Open Access Journals Sweden. Use of linear free energy relationship to predict Gibbs free energies of formation of pyrochlore phases CaMTi2O7. Using the linear free energy relationship, the Gibbs free energies of formation of various zirconolite and pyrochlore phases are calculated. The obtained materials were characterized by X-ray diffraction and infrared spectroscopy.

The carbonate content has been determined by C—H—N analysis. A thermochemical cycle was proposed and complementary experiences were performed in order to access to the standard enthalpies of formation of these phosphates. The results were compared to those previously obtained on apatites containing strontium and barium and show a decrease with the carbonate amount introduced in the lattice.

This quantity becomes more negative as the ratio of substitution increases. Estimation of the entropy of formation allowed the determination of standard Gibbs free energy of formation of these compounds. The study showed that the substitution of hydroxyl by carbonate ions contributes to the stabilisation of the apatite structure.

The standard Gibbs free energy of formation of lithium manganese oxides at the temperatures of , and K. The existence of two-voltage plateaus which appeared during charging and discharging processes in reversible intercalation of lithium into Li x Mn 2 O 4 spinel, has been discussed.

Based on obtained linear free energy relationships, it is predicted that large cations e. Inference with minimal Gibbs free energy in information field theory. Non-linear and non-Gaussian signal inference problems are difficult to tackle. Renormalization techniques permit us to construct good estimators for the posterior signal mean within information field theory IFT , but the approximations and assumptions made are not very obvious.

Here we introduce the simple concept of minimal Gibbs free energy to IFT, and show that previous renormalization results emerge naturally. They can be understood as being the Gaussian approximation to the full posterior probability, which has maximal cross information with it.

We derive optimized estimators for three applications, to illustrate the usage of the framework: i reconstruction of a log-normal signal from Poissonian data with background counts and point spread function, as it is needed for gamma ray astronomy and for cosmography using photometric galaxy redshifts, ii inference of a Gaussian signal with unknown spectrum, and iii inference of a Poissonian log-normal signal with unknown spectrum, the combination of i and ii.

Finally we explain how Gaussian knowledge states constructed by the minimal Gibbs free energy principle at different temperatures can be combined into a more accurate surrogate of the non-Gaussian posterior. Non-photosynthetic organisms use chemical disequilibria in the environment to gain metabolic energy from enzyme catalyzed oxidation-reduction redox reactions. The presence of carbon dioxide, ammonia, formaldehyde, methanol, methane and other hydrocarbons in the eruptive plume of Enceladus [1] implies diverse redox disequilibria in the interior.

In the history of the moon, redox disequilibria could have been activated through melting of a volatile-rich ice and following water-rock-organic interactions. The redox conditions in aqueous systems and amounts of available Gibbs free energy should have been affected by the production, consumption and escape of hydrogen.

Aqueous oxidation of minerals Fe-Ni metal, Fe-Ni phosphides, etc. Numerical evaluations based on concentrations of plume gases [1] reveal sufficient energy sources available to support metabolically diverse life at a wide range of activities a of dissolved H2 log aH2 from 0 to Formaldehyde, carbon dioxide [c.

Aqueous hydrogenations of acetylene, HCN and formaldehyde to produce methanol are energetically favorable as well.

Both favorable hydrogenation and hydration of HCN lead to formation of ammonia. Condensed organic species could also participate in redox reactions. Methane and ammonia are the final products of these putative redox transformations. In contrast to.

Determination of Gibbs energies of formation in aqueous solution using chemical engineering tools. Standard Gibbs energies of formation are of primary importance in the field of biothermodynamics. In the absence of any directly measured values, thermodynamic calculations are required to determine the missing data. For several biochemical species, this study shows that the knowledge of the standard Gibbs energy of formation of the pure compounds in the gaseous, solid or liquid states enables to determine the corresponding standard Gibbs energies of formation in aqueous solutions.

To do so, using chemical engineering tools thermodynamic tables and a model enabling to predict activity coefficients, solvation Gibbs energies and pKa data , it becomes possible to determine the partial chemical potential of neutral and charged components in real metabolic conditions, even in concentrated mixtures.

All rights reserved. The oxygen equilibrium pressures were determined using galvanic cells incorporating yttria stabilized zirconia as solid electrolyte.

Specification and comparative calculation of enthalpies and Gibbs formation energies of anhydrous lanthanide nitrates. Analyzed are the results of experimental depermination of formation enthalpies of waterless nitrates of lanthane cerium, praseodymium, neodymium and samarium. Using method of comparative calculation computed are enthalpies of formation of waterless lanthanide and yttrium nitrates.

Calculated values of enthalpies and Gibbs energies of waterless lanthanide nitrate formation are tabulated. We have been evaluating third derivative quantities of the Gibbs free energy , G, by graphically differentiating the second derivatives that are accessible experimentally, and demonstrated their power in elucidating the mixing schemes in aqueous solutions. Here we determine directly one of the third Determination of standard molar Gibbs energy of formation of Sm6UO12 s. The standard molar Gibbs energies of formation of Sm 6 UO 12 s have been measured using an oxygen concentration cell with yttria stabilized zirconia as solid electrolyte.

The thermodynamic properties of the upper continental crust: Exergy, Gibbs free energy and enthalpy. This paper shows a comprehensive database of the thermodynamic properties of the most abundant minerals of the upper continental crust. 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 most abundant minerals contained in it.

Finally, the chemical exergy of the continental crust is compared to the exergy of the concentrated mineral resources. However, this study shows that approximately only 0. The paper describes an absorption measurement for determining the Gibbs free energy of OH generated in a mixture of water and oxygen vapor. These measurements afford a direct verification of the accuracy of thermochemical data of H2O at high temperatures and pressures. The results indicate that values for the heat capacity of H2O obtained through numerical computations are correct within an experimental uncertainty of 0.

The organic solutions examined were nitrobenzene, 1,2-dichloroethane, benzonitrile, acetophenone, and 2-nitrophenyl octyl ether. Prediction of Gibbs energies of formation and stability constants of some secondary uranium minerals containing the uranyl group. This was done for 29 minerals containing the uranyl-ion together with phosphate, vanadate, arsenate or carbonate.

Size and shape dependent Gibbs free energy and phase stability of titanium and zirconium nanoparticles. The Debye model of Helmholtz free energy for bulk material is generalized to Gibbs free energy GFE model for nanomaterial, while a shape factor is introduced to characterize the shape effect on GFE. It is further found that GFE decreases with the shape factor and increases with decreasing of the particle size.

The critical size of structural transformation for nanoparticles goes up as temperature increases in the absence of change in shape factor. For specified temperature, the critical size climbs up with the increase of shape factor. The present predictions agree well with experiment values. Full Text Available Crude oil is generally produced with water, and the water cut produced by oil wells is increasingly common over their lifetime, so it is inevitable to create emulsions during oil production.

However, the formation of emulsions presents a costly problem in surface process particularly, both in terms of transportation energy consumption and separation efficiency. To deal with the production and operational problems which are related to crude oil emulsions, especially to ensure the separation and transportation of crude oil-water systems, it is necessary to better understand the emulsification mechanism of crude oil under different conditions from the aspects of bulk and interfacial properties.

The concept of shearing energy was introduced in this study to reveal the driving force for emulsification. The relationship between shearing stress in the flow field and interfacial tension IFT was established, and the correlation between shearing energy and interfacial Gibbs free energy was developed. The potential of the developed correlation model was validated using the experimental and field data on emulsification behavior. It was also shown how droplet deformation could be predicted from a random deformation degree and orientation angle.

The results indicated that shearing energy as the energy produced by shearing stress working in the flow field is the driving force activating the emulsification behavior. The deformation degree and orientation angle of dispersed phase droplet are associated with the interfacial properties, rheological properties and the experienced turbulence degree. The correlation between shearing stress and IFT can be quantified if droplet deformation degree vs.

When the water cut is close to the inversion point of waxy crude oil emulsion, the interfacial Gibbs free energy change decreased and the shearing energy increased. This feature is also presented in the special regions where.

Extrapolation procedures for calculating high-temperature gibbs free energies of aqueous electrolytes. Methods for calculating high-temprature Gibbs free energies of mononuclear cations and anions from room-temperature data are reviewed.

Emphasis is given to species required for oxide solubility calculations relevant to mass transport situations in the nuclear industry. Free energies predicted by each method are compared to selected values calculated from recently reported solubility studies and other literature data. From K to K, free energies from an electrostatic model for ion hydration are more accurate. Extrapolations for hydrolyzed species are limited by a lack of room-temperature entropy data and expressions for estimating these entropies are discussed.


donnan effect

The Gibbs—Donnan effect also known as the Donnan's effect , Donnan law , Donnan equilibrium , or Gibbs—Donnan equilibrium is a name for the behaviour of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane. Because small cations are attracted, but are not bound to the proteins, small anions will cross capillary walls away from the anionic proteins more readily than small cations. Thus, some ionic species can pass through the barrier while others cannot. The solutions may be gels or colloids as well as solutions of electrolytes , and as such the phase boundary between gels, or a gel and a liquid, can also act as a selective barrier. The electric potential arising between two such solutions is called the Donnan potential. Donnan who studied it experimentally in The Donnan equilibrium is prominent in the triphasic model for articular cartilage proposed by Mow and Lai, as well as in electrochemical fuel cells and dialysis.





Gibbs–Donnan effect


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