WorldWideScience

Sample records for aqueous phase equilibria

  1. Phase equilibria in a system of aqueous arginine with an octane solution of sulfonic acid

    Science.gov (United States)

    Kuvaeva, Z. I.; Koval'chuk, I. V.; Vodop'yanova, L. A.; Soldatov, V. S.

    2013-05-01

    The extraction of arginine (Arg) from aqueous salt (0.1 M NaCl) solutions with a sulfo extractant in a wide range of pH values and amino acid concentrations was studied. The 0.1 M solution of dinonylnaphthalenesulfonic acid (HD) in octane was used as an extractant. The degree of extraction was found to be high at pH 0.8-9.0. This can be explained by the effect of additional intermolecular interactions in the extractant phase involving the guanidine group of Arg.

  2. Hydrate phase equilibria of CO2+N2+aqueous solution of THF, TBAB or TBAF system

    DEFF Research Database (Denmark)

    Sfaxi, Imen Ben Attouche; Durand, Isabelle; Lugo, Rafael

    2014-01-01

    We report hydrate dissociation conditions of CO2 (15 and 30mol%)+N2 (85 and 70mol%) in the presence of aqueous solutions of THF, TBAB or TBAF. The concentrations of TBAB and TBAF in the aqueous solutions are 5wt% and 9wt% while THF concentration in aqueous solution is 3mol%. Two different experim...

  3. Phase equilibria basic principles, applications, experimental techniques

    CERN Document Server

    Reisman, Arnold

    2013-01-01

    Phase Equilibria: Basic Principles, Applications, Experimental Techniques presents an analytical treatment in the study of the theories and principles of phase equilibria. The book is organized to afford a deep and thorough understanding of such subjects as the method of species model systems; condensed phase-vapor phase equilibria and vapor transport reactions; zone refining techniques; and nonstoichiometry. Physicists, physical chemists, engineers, and materials scientists will find the book a good reference material.

  4. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng

    2013-01-01

    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  5. Phase equilibria of carbohydrates in polar solvents

    DEFF Research Database (Denmark)

    Jonsdottir, Svava Osk; Rasmussen, Peter

    1999-01-01

    A method for calculating interaction energies and interaction parameters with molecular mechanics methods is extended to predict solid-liquid equilibria (SLE) for saccharides in aqueous solution, giving results in excellent agreement with experimental values. Previously, the method has been shown...

  6. Liquid–liquid equilibria in the quinary aqueous two-phase system of poly(ethylene glycol) 6000 + sodium sulfate + water in the presence of glucose and ethanol: Experimental investigation and thermodynamic modeling

    International Nuclear Information System (INIS)

    Hekayati, Javad; Roosta, Aliakbar; Javanmardi, Jafar

    2016-01-01

    Highlights: • Quinary LLE phase equilibria involving PEG 6000 + Na_2SO_4 + H_2O + glucose + ethanol. • Favorable partition coefficients of ethanol and glucose. • Satisfactory correlation of the LLE experimental data with the original NRTL model. • Root mean squared deviations (RMSDs) of less than 0.6%. - Abstract: Extractive fermentation processes involving aqueous two-phase systems (ATPSs) are considered as viable means of overcoming the problems associated with product inhibition. Practical development of these processes requires accurate knowledge of the liquid–liquid equilibrium (LLE) of the ATPS forming components alongside the substrate and product of the fermentation process. In this work, the quinary aqueous two-phase LLE of poly(ethylene glycol) 6000 + sodium sulfate + water in the presence of glucose and ethanol have been experimentally determined at 298.15 K using spectrophotometric methods. The resulting LLE data were then satisfactorily correlated by the non-random two-liquid (NRTL) activity coefficient model based on mass fractions. In doing so, the binary energy interaction parameters of the NRTL activity coefficient model were obtained and reported. Calculated RMS deviations below 0.6% demonstrate that the original NRTL activity coefficient model can accurately correlate the LLE data of the quinary aqueous biphasic system of interest.

  7. Liquid–liquid equilibria in the quinary aqueous two-phase system of poly(ethylene glycol) 6000 + sodium sulfate + water in the presence of glucose and ethanol: Experimental investigation and thermodynamic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hekayati, Javad; Roosta, Aliakbar, E-mail: aa.roosta@sutech.ac.ir; Javanmardi, Jafar

    2016-02-10

    Highlights: • Quinary LLE phase equilibria involving PEG 6000 + Na{sub 2}SO{sub 4} + H{sub 2}O + glucose + ethanol. • Favorable partition coefficients of ethanol and glucose. • Satisfactory correlation of the LLE experimental data with the original NRTL model. • Root mean squared deviations (RMSDs) of less than 0.6%. - Abstract: Extractive fermentation processes involving aqueous two-phase systems (ATPSs) are considered as viable means of overcoming the problems associated with product inhibition. Practical development of these processes requires accurate knowledge of the liquid–liquid equilibrium (LLE) of the ATPS forming components alongside the substrate and product of the fermentation process. In this work, the quinary aqueous two-phase LLE of poly(ethylene glycol) 6000 + sodium sulfate + water in the presence of glucose and ethanol have been experimentally determined at 298.15 K using spectrophotometric methods. The resulting LLE data were then satisfactorily correlated by the non-random two-liquid (NRTL) activity coefficient model based on mass fractions. In doing so, the binary energy interaction parameters of the NRTL activity coefficient model were obtained and reported. Calculated RMS deviations below 0.6% demonstrate that the original NRTL activity coefficient model can accurately correlate the LLE data of the quinary aqueous biphasic system of interest.

  8. Isotope effects in ion-exchange equilibria in aqueous and mixed solvent systems

    International Nuclear Information System (INIS)

    Gupta, A.R.

    1979-01-01

    Isotope effects in ion-exchange equilibria in aqueous and mixed solvents are analyzed in terms of the general features of ion-exchange equilibria and of isotope effects in chemical equilibria. The special role of solvent fractionation effects in ion-exchange equilibria in mixed solvents is pointed out. The various situations arising in isotope fractionation in ion exchange in mixed solvents due to solvent fractionation effects are theoretically discussed. The experimental data on lithium isotope effects in ion-exchange equilibria in mixed solvents are shown to conform to the above situations. The limitations of ion-exchange equilibria in mixed solvents for isotope fractionation are pointed out. 3 tables

  9. Solid-phase equilibria on Pluto's surface

    Science.gov (United States)

    Tan, Sugata P.; Kargel, Jeffrey S.

    2018-03-01

    Pluto's surface is covered by volatile ices that are in equilibrium with the atmosphere. Multicomponent phase equilibria may be calculated using a thermodynamic equation of state and, without additional assumptions, result in methane-rich and nitrogen-rich solid phases. The former is formed at temperature range between the atmospheric pressure-dependent sublimation and condensation points, while the latter is formed at temperatures lower than the sublimation point. The results, calculated for the observed 11 μbar atmospheric pressure and composition, are consistent with recent work derived from observations by New Horizons.

  10. Phase equilibria and phase structures of polymer blends

    International Nuclear Information System (INIS)

    Chalykh, Anatolii E; Gerasimov, Vladimir K

    2004-01-01

    Experimental, methodical and theoretical studies dealing with phase equilibria and phase structures of polymer blends are generalised. The general and specific features of the change in solubility of polymers with changes in the molecular mass and copolymer composition and upon the formation of three-dimensional cross-linked networks are described. The results of the effect of the prehistory on the phase structure and the non-equilibrium state of polymer blends are considered in detail.

  11. Quaternary (liquid + liquid) equilibria of aqueous two-phase polyethylene glycol, poly-N-vinylcaprolactam, and KH{sub 2}PO{sub 4}: Experimental and the generalized Flory-Huggins theory

    Energy Technology Data Exchange (ETDEWEB)

    Foroutan, Masumeh [Department of Physical Chemistry, Faculty of Chemistry, College of Science, University of Tehran, Enghelab Ave., Tehran 14155-6455 (Iran, Islamic Republic of)], E-mail: foroutan@khayam.ut.ac.ir; Zarrabi, Mona [Department of Physical Chemistry, Faculty of Chemistry, College of Science, University of Tehran, Enghelab Ave., Tehran 14155-6455 (Iran, Islamic Republic of)

    2008-06-15

    A quaternary (liquid + liquid) equilibrium study was performed to focus attention on the interaction parameters between poly-N-vinylcaprolactam (PVCL) and poly-ethylene glycol (PEG) as well as between other species. At first, the new experimental data of (liquid + liquid) equilibria for aqueous two-phase systems containing PEG, KH{sub 2}PO{sub 4}, and PVCL at T = 303.15 K have been determined. Then the Flory-Huggins theory with two electrostatic terms (the Debye-Huckel and the Pitzer-Debye-Huckel equations) has been generalized to correlate the phase behavior of the quaternary system. Good agreement has been found between experimental and calculated data from both models especially from the Pitzer-Debye-Huckel equation. Also an effort was done to compare the effect of temperature as well as addition of PVCL on the binodal curves of PEG, KH{sub 2}PO{sub 4}, and water. The effect of the type of salt on the binodals has been also studied, and the salting out power of the salts has been determined.

  12. Phase equilibria of hydrogen sulfide and carbon dioxide simple hydrates in the presence of methanol, (methanol + NaCl) and (ethylene glycol + NaCl) aqueous solutions

    International Nuclear Information System (INIS)

    Mohammadi, Amir H.; Richon, Dominique

    2012-01-01

    Highlights: → Dissociation conditions of H 2 S or CO 2 hydrate + inhibitor aqueous solution are reported. → Methanol, methanol + NaCl and EG + NaCl aqueous solutions are considered as inhibitors. → Comparisons are made between our experimental data and the corresponding literature data. - Abstract: This work aims at reporting the dissociation pressures of hydrogen sulfide and carbon dioxide simple hydrates in the presence of methanol, (methanol + NaCl) and (ethylene glycol + NaCl) aqueous solutions at different temperatures and various concentrations of inhibitor in aqueous solution. The equilibrium results were generated using an isochoric pressure-search method. These values are compared with some selected experimental data from the literature on the dissociation conditions of hydrogen sulfide and carbon dioxide simple hydrates in the presence of pure water to show the inhibition effects of the above mentioned aqueous solutions. Comparisons are finally made between our experimental values and the corresponding literature data. Some disagreements among the literature data and our data are found.

  13. High-pressure fluid-phase equilibria: Experimental methods and systems investigated (2000-2004)

    DEFF Research Database (Denmark)

    Dohrn, Ralf; Peper, Stephanie; Fonseca, José

    2010-01-01

    As a part of a series of reviews, a compilation of systems for which high-pressure phase-equilibrium data were published between 2000 and 2004 is given. Vapor-liquid equilibria, liquid-liquid equilibria, vapor-liquid-liquid equilibria,solid-liquid equilibria, solid-vapor equilibria, solid-vapor-l...

  14. Phase equilibria in chemical reactive fluid mixtures

    International Nuclear Information System (INIS)

    Maurer, Gerd

    2011-01-01

    Downstream processing is a major part of nearly all processes in the chemical industries. Most separation processes in the chemical (and related) industries for fluid mixtures are based on phase equilibrium phenomena. The majority of separation processes can be modelled assuming that chemical reactions are of no (or very minor) importance, i.e., assuming that the overall speciation remains unchanged during a separation process. However, there are also a large number of industrially important processes where the thermodynamic properties are influenced by chemical reactions. The phase equilibrium of chemical reactive mixtures has been a major research area of the author's group over nearly 40 years. In this contribution, three examples from that research are discussed. The first example deals with the vapour phase dimerisation of carboxylic acids and its consequences on phase equilibrium phenomena and phase equilibrium predictions. The second example deals with the solubility of sour gases (e.g., carbon dioxide and sulfur dioxide) in aqueous solutions of ammonia. That topic has been of interest for many years, e.g., in relation with the gasification and liquefaction of coal and, more recently, with the removal of carbon dioxide from flue gas in the 'chilled ammonia process'. The third example deals with phase equilibrium phenomena in aqueous solutions of polyelectrolytes. It deals with the phenomenon of 'counter ion condensation' and methods to model the Gibbs free energy of such solutions.

  15. Gas hydrate phase equilibria measurement techniques and phase rule considerations

    International Nuclear Information System (INIS)

    Beltran, Juan G.; Bruusgaard, Hallvard; Servio, Phillip

    2012-01-01

    Highlights: → Inconsistencies found in hydrate literature. → Clarification to the number of variables needed to satisfy and justify equilibrium data. → Application of phase rule to mixed hydrate systems. → Thermodynamically consistent format to present data. - Abstract: A brief review of the Gibbs phase rule for non-reacting systems and its correct application to clathrate hydrates is presented. Clarification is provided for a common mistake found in hydrate phase-equilibria literature, whereby initial compositions are used as intensive variables to satisfy the Gibbs phase rule instead of the equilibrium values. The system of (methane + carbon dioxide + water) under (hydrate + liquid + vapor) equilibrium is used as a case study to illustrate key points and suggestions to improve experimental techniques are proposed.

  16. Stability of equilibria for a two-phase osmosis model

    NARCIS (Netherlands)

    Lippoth, F.; Prokert, G.

    2012-01-01

    For a two-phase moving boundary problem modelling the motion of a semipermeable membrane by osmotic pressure and surface tension, we prove that the manifold of equilibria is locally exponentially attractive. Our method relies on maximal regularity results for parabolic systems with relaxation type

  17. Predicting phase equilibria in one-component systems

    Science.gov (United States)

    Korchuganova, M. R.; Esina, Z. N.

    2015-07-01

    It is shown that Simon equation coefficients for n-alkanes and n-alcohols can be modeled using critical and triple point parameters. Predictions of the phase liquid-vapor, solid-vapor, and liquid-solid equilibria in one-component systems are based on the Clausius-Clapeyron relation, Van der Waals and Simon equations, and the principle of thermodynamic similarity.

  18. Phase diagrams and heterogeneous equilibria a practical introduction

    CERN Document Server

    Predel, Bruno; Pool, Monte

    2004-01-01

    This graduate-level textbook provides an introduction to the practical application of phase diagrams. It is intended for students and researchers in chemistry, metallurgy, mineralogy, and materials science as well as in engineering and physics. Heterogeneous equilibria are described by a minimum of theory illustrated by practical examples and realistic case discussions from the different fields of application. The treatment of the physical and energetic background of phase equilibria leads to the discussion of the thermodynamics of mixtures and the correlation between energetics and composition. Thus, tools for the prediction of energetic, structural, and physical quantities are provided. The authors treat the nucleation of phase transitions, the production and stability of technologically important metastable phases, and metallic glasses. Furthermore, the text also concisely presents the thermodynamics and composition of polymer systems.

  19. Simulating Osmotic Equilibria: A New Tool for Calculating Activity Coefficients in Concentrated Aqueous Salt Solutions.

    Science.gov (United States)

    Bley, Michael; Duvail, Magali; Guilbaud, Philippe; Dufrêche, Jean-François

    2017-10-19

    Herein, a new theoretical method is presented for predicting osmotic equilibria and activities, where a bulk liquid and its corresponding vapor phase are simulated by means of molecular dynamics using explicit polarization. Calculated time-averaged number density profiles provide the amount of evaporated molecules present in the vapor phase and consequently the vapor-phase density. The activity of the solvent and the corresponding osmotic coefficient are determined by the vapor density at different solute concentrations with respect to the reference vapor density of the pure solvent. With the extended Debye-Hückel equation for the activity coefficient along with the corresponding Gibbs-Duhem relation, the activity coefficients of the solutes are calculated by fitting the osmotic coefficients. A simple model based on the combination of Poisson processes and Maxwell-Boltzmann velocity distributions is introduced to interpret statistical phenomena observed during the simulations, which are related to evaporation and recondensation. This method is applied to aqueous dysprosium nitrate [Dy(NO 3 ) 3 ] solutions at different concentrations. The obtained densities of the liquid bulk and the osmotic and activity coefficients are in good agreement with the experimental results for concentrated and saturated solutions. Density profiles of the liquid-vapor interface at different concentrations provide detailed insight into the spatial distributions of all compounds.

  20. Extended Group Contribution Model for Polyfunctional Phase Equilibria

    DEFF Research Database (Denmark)

    Abildskov, Jens

    of physical separation processes. In a thermodynamic sense, design requires detailed knowledge of activity coefficients in the phases at equilibrium. The prediction of these quantities from a minimum of experimental data is the broad scope of this thesis. Adequate equations exist for predicting vapor......Material and energy balances and equilibrium data form the basis of most design calculations. While material and energy balances may be stated without much difficulty, the design engineer is left with a choice between a wide variety of models for describing phase equilibria in the design......-liquid equilibria from data on binary mixtures, composed of structurally simple molecules with a single functional group. More complex is the situation with mixtures composed of structurally more complicated molecules or molecules with more than one functional group. The UNIFAC method is extended to handle...

  1. On phase equilibria in duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Wessman, S. [Swerea KIMAB AB, Stockholm (Sweden); Pettersson, R. [Outokumpu Stainless AB, Avesta Research Centre, Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Stockholm (Sweden)

    2010-05-15

    The equilibrium conditions of four duplex stainless steels; Fe-23Cr-4.5Ni-0.1N, Fe-22Cr-5.5Ni-3Mo-0.17N, Fe-25Cr-7Ni-4Mo-0.27N and Fe-25Cr-7Ni-4Mo-1W-1.5Cu-0.27N were studied in the temperature region from 700 to 1000 C. Phase compositions were determined with SEM EDS and the phase fractions using image analysis on backscattered SEM images. The results showed that below 1000 C the steels develop an inverse duplex structure with austenite and sigma phase, of which the former is the matrix phase. With decreasing temperature, the microstructure will be more and more complex and finely dispersed. The ferrite is, for the higher alloyed steels, only stable above 1000 C and at lower temperatures disappears in favour of intermetallic phases. The major intermetallic phase is sigma phase with small amounts of chi phase, the latter primarily in high Mo and W grades. Nitrides, not a focus in this investigation, were present as rounded particles and acicular precipitates at lower temperatures. The results were compared to theoretical predictions using the TCFE5 and TCFE6 databases. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. Equilibria in aqueous cadmium-chloroacetate-glycinate systems. A convolution-deconvolution cyclic voltammetric study

    International Nuclear Information System (INIS)

    Abdel-Hamid, R.; Rabia, M.K.M.

    1994-01-01

    Stability constants and composition of cadmium-glycinate binary complexes were determined using cyclic voltammetry. Furthermore, binary and ternary complex equilibria for chloroacetates and glycinate with cadmium in 0.1 M aqueous KNO 3 at pH 10.4 and 298 K were investigated. Cadmium forms binary complexes with chloroacetates of low stability and ternary ones with chloroacetate-glycinate of significant stability. (author)

  3. High-pressure fluid phase equilibria phenomenology and computation

    CERN Document Server

    Deiters, Ulrich K

    2012-01-01

    The book begins with an overview of the phase diagrams of fluid mixtures (fluid = liquid, gas, or supercritical state), which can show an astonishing variety when elevated pressures are taken into account; phenomena like retrograde condensation (single and double) and azeotropy (normal and double) are discussed. It then gives an introduction into the relevant thermodynamic equations for fluid mixtures, including some that are rarely found in modern textbooks, and shows how they can they be used to compute phase diagrams and related properties. This chapter gives a consistent and axiomatic approach to fluid thermodynamics; it avoids using activity coefficients. Further chapters are dedicated to solid-fluid phase equilibria and global phase diagrams (systematic search for phase diagram classes). The appendix contains numerical algorithms needed for the computations. The book thus enables the reader to create or improve computer programs for the calculation of fluid phase diagrams. introduces phase diagram class...

  4. Phase Equilibria Relationships of High-Tc Superconductors

    International Nuclear Information System (INIS)

    Wong-Ng, Winnie

    2011-01-01

    As an integral part of a R and D program partially supported by the Electricity Delivery and Energy Reliability Office of DOE, we have determined phase equilibria data and phase diagrams for the three generations of superconductor materials: 1st generation, (Bi,Pb)-Sr-Ca- Cu-O systems; 2nd generation, Ba-R-Cu-O systems (R=lanthanides and yttrium); and 3rd generation, MgB2 systems. Our studies involved bulk materials, single crystals and thin films. This report gives a summary of our accomplishments, a list of publications, and 15 selected journal publications.

  5. High temperature interdiffusion and phase equilibria in U-Mo

    International Nuclear Information System (INIS)

    Lundberg, L.B.

    1988-01-01

    Experimental data for interdiffusion and phase equilibria in the U-Mo system have been obtained over the temperature range 1400 to 1525 K as a fallout from compatibility experiments in which UO 2 was decomposed by lithium in closed molybdenum capsules. Composition-position, x-ray diffraction and microstructural data from the interdiffusion zones indicate that the intermediate phase U 2 Mo is found in this temperature range, contrary to the currently accepted equilibrium U-Mo phase diagram. The U-Mo interdiffusion data are in good agreement with published values. Inclusion of the U 2 Mo phase in a theoretical correlation of interdiffusion and phase equilibria data using Darken's equation indicate that high temperature interdiffusion of uranium and molybdenum follows the usual thermodynamic rules. Significant changes in the value of the thermodynamic based Darken factor near the U 2 Mo phase boundary on the high uranium side are indicated from both the new and published interdiffusion data. 9 refs., 10 figs., 3 tabs

  6. Phase equilibria of the Mo-Al-Ho ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yitai; Chen, Xiaoxian; Liu, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

    2017-08-15

    Investigation into the reactions and phase equilibria of transition metal elements (i.e. Mo, Zr, Cr, V and Ti), Al and rare earths is academically and industrially important for the development of both refractory alloys and lightweight high-temperature materials. In this work, the equilibria of the Mo-Al-Ho ternary system at 773 K have been determined by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al{sub 4}Mo{sub 2}Ho has been found and the other ternary phase Al{sub 43}Mo{sub 4}Ho{sub 6} is observed. Ten binary phases in the Al-Mo and Al-Ho systems, including Al{sub 17}Mo{sub 4} rather than Al{sub 4}Mo, have been determined to exist at 773 K. The homogeneity ranges of AlMo{sub 3} and Al{sub 8}Mo{sub 3} phase are 7.5 at.% and 1 at.%, respectively. According to the phase-disappearing method, the maximum solubility of Al in Mo is about 16 at.%.

  7. Phase equilibria in the niobium-vanadium-hydrogen system

    Energy Technology Data Exchange (ETDEWEB)

    Bethin, J. (Grumman Aerospace Corp., Bethpage, NY (USA)); Welch, D.O. (Brookhaven National Lab., Upton, NY (USA)); Pick, M.A. (Commission of the European Communities, Abingdon (UK). JET Joint Undertaking)

    1990-01-01

    The effect of vanadium additions to niobium on the metal-hydrogen phase equilibria has been studied. Measurements of the equilibrium H{sub 2}(D{sub 2}) pressure-composition-temperature isotherms for Nb{sub 1-x}V{sub x} alloys with 0{le}x<0.2 were used to determine the depression of the {alpha} - {alpha}' critical temperature with increasing vanadium concentration. A simple lattice-fluid model guided reduction of the data. Changes in the triple point temperature as well as the shift of the {zeta} {yields} {epsilon} phase transition were determined by differential scanning calorimetry measurements. A rapid overall depression was found, of the order of 7 K (at.% substituted V){sup -1}, for the metal-hydrogen (deuterium) phase boundary structure when compared with the Nb-H system in the hydrogen concentration range of interest. The results explain the enhanced terminal solubility of hydrogen in this system found previously by other authors. The changes in the phase equilibria are discussed in terms of the effect of hydrogen trapping and compared with the results of a cluster-variation calculation for random-field systems of previous authors, taking into account a distribution of H-site energies due to alloying. (author).

  8. Phase equilibria and critical phenomena in the cesium nitrate-water-diethylamine ternary system

    International Nuclear Information System (INIS)

    Il'in, K.K.; Kurskij, V.F.; Cherkasov, D.G.

    2008-01-01

    Phase equilibria and critical events in ternary cesium nitrate-water-diethylamine system, where border binary liquid system is characterized by aliquation with lower critical temperature of solution (LCTS), have been investigated by visual-polythermal method in the 60-150 Deg C range. Interaction of cesium nitrate in the water-diethylamine system leads to lowering of its LCTS from 146.1 to 69.3 Deg C and decrease of mutual solubility. Distribution ratios of diethylamine between water and organic phases of monotectic equilibrium are calculated at different temperatures. Diethylamine salting out from aqueous solutions by cesium nitrates becomes stronger with rising temperature. Plotted isotherms of phase confirms generalized scheme of topological transformations of ternary systems phase diagrams: salt-binary solvent with salting out

  9. Electronic structure and phase equilibria in ternary substitutional alloys

    International Nuclear Information System (INIS)

    Traiber, A.J.S.; Allen, S.M.; Waterstrat, R.M.

    1996-01-01

    A reliable, consistent scheme to study phase equilibria in ternary substitutional alloys based on the tight-binding approximation is presented. With electronic parameters from linear muffin-tin orbital calculations, the computed density of states and band structures compare well with those from more accurate abinitio calculations. Disordered alloys are studied within the tight-binding coherent-potential approximation extended to alloys; energetics of ordered systems are obtained through effective pair interactions computed with the general perturbation method; and partially ordered alloys are studied with a novel simplification of the molecular coherent-potential approximation combined with the general perturbation method. The formalism is applied to bcc-based Zr-Ru-Pd alloys which are promising candidates for medical implant devices. Using energetics obtained from the above scheme, we apply the cluster- variation method to study phase equilibria for particular pseudo- binary alloys and show that results are consistent with observed behavior of electronic specific heat coefficient with composition for Zr 0.5 (Ru, Pd) 0.5

  10. Metamorphism and partial melting of ordinary chondrites: Calculated phase equilibria

    Science.gov (United States)

    Johnson, T. E.; Benedix, G. K.; Bland, P. A.

    2016-01-01

    Constraining the metamorphic pressures (P) and temperatures (T) recorded by meteorites is key to understanding the size and thermal history of their asteroid parent bodies. New thermodynamic models calibrated to very low P for minerals and melt in terrestrial mantle peridotite permit quantitative investigation of high-T metamorphism in ordinary chondrites using phase equilibria modelling. Isochemical P-T phase diagrams based on the average composition of H, L and LL chondrite falls and contoured for the composition and abundance of olivine, ortho- and clinopyroxene, plagioclase and chromite provide a good match with values measured in so-called equilibrated (petrologic type 4-6) samples. Some compositional variables, in particular Al in orthopyroxene and Na in clinopyroxene, exhibit a strong pressure dependence when considered over a range of several kilobars, providing a means of recognising meteorites derived from the cores of asteroids with radii of several hundred kilometres, if such bodies existed at that time. At the low pressures (recorders of peak conditions. The intersection of isopleths of these variables may allow pressures to be quantified, even at low P, permitting constraints on the minimum size of parent asteroid bodies. The phase diagrams predict the onset of partial melting at 1050-1100 °C by incongruent reactions consuming plagioclase, clinopyroxene and orthopyroxene, whose compositions change abruptly as melting proceeds. These predictions match natural observations well and support the view that type 7 chondrites represent a suprasolidus continuation of the established petrologic types at the extremes of thermal metamorphism. The results suggest phase equilibria modelling has potential as a powerful quantitative tool in investigating, for example, progressive oxidation during metamorphism, the degree of melting and melt loss or accumulation required to produce the spectrum of differentiated meteorites, and whether the onion shell or rubble pile

  11. (Solid + liquid) isothermal evaporation phase equilibria in the aqueous ternary system (Li{sub 2}SO{sub 4} + MgSO{sub 4} + H{sub 2}O) at T = 308.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shiqiang [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Deng Tianlong [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); College of Materials, Chemistry and Chemical Engineering, Chengdu University Technology, Chengdu 610059 (China)], E-mail: dtl@cdut.edu.cn

    2008-06-15

    The solubility and the density in the aqueous ternary system (Li{sub 2}SO{sub 4} + MgSO{sub 4} + H{sub 2}O) at T = 308.15 K were determined by the isothermal evaporation. Our experimental results permitted the construction of the phase diagram and the plot of density against composition. It was found that there is one eutectic point for (Li{sub 2}SO{sub 4} . H{sub 2}O + MgSO{sub 4} . 7H{sub 2}O), two univariant curves, and two crystallization regions corresponding to lithium sulphate monohydrate (Li{sub 2}SO{sub 4} . H{sub 2}O) and epsomite (MgSO{sub 4} . 7H{sub 2}O). The system belongs to a simple co-saturated type, and neither double salts nor solid solution was found. Based on the Pitzer ion-interaction model and its extended HW models of aqueous electrolyte solution, the solubility of the ternary system at T = 308.15 K has been calculated. The predicted solubility agrees well with the experimental values.

  12. Phase equilibria and molecular interaction studies on (naphthols + vanillin) systems

    International Nuclear Information System (INIS)

    Gupta, Preeti; Agrawal, Tanvi; Das, Shiva Saran; Singh, Nakshatra Bahadur

    2012-01-01

    Highlights: ► Phase equilibria of (naphthol + vanillin) systems have been studied for the first time. ► Eutectic type phase diagrams are obtained. ► Eutectic mixtures show nonideal behaviour. ► There is a weak molecular interaction between the components in the eutectic mixtures. ► α-Naphthol–vanillin eutectic is more stable as compared to β-naphthol–vanillin. - Abstract: Phase equilibria between (α-naphthol + vanillin) and (β-naphthol + vanillin) systems have been studied by thaw-melt method and the results show the formation of simple eutectic mixtures. Crystallization velocities of components and eutectic mixtures were determined at different stages under cooling. With the help of differential scanning calorimeter (DSC), the enthalpy of fusion of components and eutectic mixtures was determined and from the values excess thermodynamic functions viz., excess Gibbs free energy (G E ), excess entropy (S E ), excess enthalpy (H E ) of hypo-, hyper- and eutectic mixtures were calculated. Flexural strength measurements were made in order to understand the non-ideal nature of eutectics. FT-IR spectral studies indicate the formation of hydrogen bond in the eutectic mixture. Anisotropic and isotropic microstructural studies of components, hypo-, hyper- and eutectic mixtures were made. Jackson’s roughness parameter was calculated and found to be greater than 2 suggesting the faceted morphology with irregular structures. The overall results have shown that there is a weak molecular interaction between the components in the eutectic mixtures and the (α-naphthol + vanillin) eutectic is more stable as compared to the (β-naphthol + vanillin) eutectic system.

  13. Phase Equilibria of Sn-Co-Cu Ternary System

    Science.gov (United States)

    Chen, Yu-Kai; Hsu, Chia-Ming; Chen, Sinn-Wen; Chen, Chih-Ming; Huang, Yu-Chih

    2012-10-01

    Sn-Co-Cu ternary alloys are promising lead-free solders, and isothermal sections of Sn-Co-Cu phase equilibria are fundamentally important for the alloys' development and applications. Sn-Co-Cu ternary alloys were prepared and equilibrated at 523 K, 1073 K, and 1273 K (250 °C, 800 °C, and 1000 °C), and the equilibrium phases were experimentally determined. In addition to the terminal solid solutions and binary intermetallic compounds, a new ternary compound, Sn3Co2Cu8, was found. The solubilities of Cu in the α-CoSn3 and CoSn2 phases at 523 K (250 °C) are 4.2 and 1.6 at. pct, respectively, while the Cu solubility in the α-Co3Sn2 phase is as high as 20.0 at. pct. The Cu solubility increases with temperature and is around 30.0 at. pct in the β-Co3Sn2 at 1073 K (800 °C). The Co solubility in the η-Cu6Sn5 phase is also significant and is 15.5 at. pct at 523 K (250 °C).

  14. Redox Equilibria Involving Chromium Minerals in Aqueous Fluids in the Deep Earth - Implications for Diamond Formation

    Science.gov (United States)

    Huang, J.; Huang, F.; Hao, J.; Sverjensky, D. A.

    2017-12-01

    Diamonds are often associated with inclusions of garnet that are characteristically Cr-rich and Ca-poor, suggesting metasomatic reactions involving fluids [1]. To investigate these reactions, we developed a thermodynamic characterization of Cr-bearing minerals and integrated it with our database for the thermodynamic properties of aqueous Cr-species [2]. We retrieved thermodynamic properties of picrochromite (MgCr2O4), and knorringite (Mg3Cr2Si3O12) consistent with minerals in the Berman (1988) using calorimetric data and experimental phase equilibria involving the reactions: MgCr2O4 + SiO2 = Cr2O3 + MgSiO3 [2] and MgCr2O4 + 4MgSiO3 = Mg3Cr2Si3O12 + Mg2SiO4 [3], respectively.At high temperatures and pressures, neutral pH and FMQ, the predicted solubilities of eskolaite and knorringite equilibrium with Cr2+ in a pure water system are very low. However, we found that complexes of Cr2+ and Cl- could increase the solubilities of chromium minerals significantly. At 500°C and 0.2 - 1.0 GPa, we retrieved the CrCl(OH)0 neutral complex from experiments on the solubility of Cr2O3 in HCl solutions [4]. At 1,000°C and 4.0 GPa, we retrieved the properties of a CrCl3- complex from experiments on the solubility of Cr2O3 in KCl solutions [5]. The predicted solubility of a garnet containing 23 mole% of knorringite in equilibrium with CrCl3- in a peridotitic diamond-forming fluid is 22 millimolal (1,144 ppm). This result suggests that a redox reaction relating to diamond formation might involveMg3Al2Si3O12 + 0.5CO2(aq) + 2 CrCl3- + 2H+ = Mg3Cr2Si3O12 + 0.5C-Diamond + 2Al3+ + 6Cl-. In this way, high temperature and pressure fluids containing Cr(II)-complexes might promote the mobility of chromium and be involved in metasomatic reactions and diamond formation.[1]Boyd et al. (1993)[2] Hao et al. (submitted to Geochem. Persp. Letters)[3] Berman (1988)[4] Klemme et al. (2000)[5] Klemme et al. (2004)[6] Watenphul et al. (2014)[7] Klein-BenDavid et al. (2011)

  15. Thermodynamics and phase equilibria of ternary systems relevant to contact materials for compound semiconductors

    International Nuclear Information System (INIS)

    Ipser, H.; Richter, K.; Micke, K.

    1997-01-01

    In order to investigate the stability of ohmic contacts to compound semiconductors, it is necessary to know the phase equilibria in the corresponding multi-component systems. We are currently studying the phase equilibria and thermophysical properties of several ternary systems which are of interest in view of the use of nickel, palladium and platinum as contact materials for GaSb and InSb compound semiconductors: Ga-Ni-Sb, In-Ni-Sb, Ga-Pd-Sb and Ga-Pt-Sb. Phase equilibria are investigated by thermal analyses, X-ray powder diffraction methods as well as electron microprobe analysis. Thermodynamic properties are derived from vapour pressure measurements using an isopiestic method. It is planned to combine all information on phase equilibria and thermochemistry for the ternary and the limiting binary systems to perform an optimization of the ternary systems by computer calculations using standard software. (author)

  16. Simulation of the high-pressure phase equilibria of hydrocarbon-water/brine systems

    DEFF Research Database (Denmark)

    Zuo, You-Xiang; Stenby, Erling Halfdan; Guo, Tian-Min

    1996-01-01

    The major objectives of this work are: (1) extend the modified Patel-Teja (MPT) equation of state proposed for aqueous electrolyte systems (Zuo and Guo, 1991) to describe the liquid-liquid and vapor-liquid-liquid equilibria of hydrocarbon-water/brine systems through introducing an unconventional...

  17. Phase equilibria constraints on models of subduction zone magmatism

    Science.gov (United States)

    Myers, James D.; Johnston, Dana A.

    Petrologic models of subduction zone magmatism can be grouped into three broad classes: (1) predominantly slab-derived, (2) mainly mantle-derived, and (3) multi-source. Slab-derived models assume high-alumina basalt (HAB) approximates primary magma and is derived by partial fusion of the subducting slab. Such melts must, therefore, be saturated with some combination of eclogite phases, e.g. cpx, garnet, qtz, at the pressures, temperatures and water contents of magma generation. In contrast, mantle-dominated models suggest partial melting of the mantle wedge produces primary high-magnesia basalts (HMB) which fractionate to yield derivative HAB magmas. In this context, HMB melts should be saturated with a combination of peridotite phases, i.e. ol, cpx and opx, and have liquid-lines-of-descent that produce high-alumina basalts. HAB generated in this manner must be saturated with a mafic phase assemblage at the intensive conditions of fractionation. Multi-source models combine slab and mantle components in varying proportions to generate the four main lava types (HMB, HAB, high-magnesia andesites (HMA) and evolved lavas) characteristic of subduction zones. The mechanism of mass transfer from slab to wedge as well as the nature and fate of primary magmas vary considerably among these models. Because of their complexity, these models imply a wide range of phase equilibria. Although the experiments conducted on calc-alkaline lavas are limited, they place the following limitations on arc petrologic models: (1) HAB cannot be derived from HMB by crystal fractionation at the intensive conditions thus far investigated, (2) HAB could be produced by anhydrous partial fusion of eclogite at high pressure, (3) HMB liquids can be produced by peridotite partial fusion 50-60 km above the slab-mantle interface, (4) HMA cannot be primary magmas derived by partial melting of the subducted slab, but could have formed by slab melt-peridotite interaction, and (5) many evolved calc

  18. Phase Equilibria and Compressibility of bastnaesite-(La)

    Science.gov (United States)

    Rowland, R. L., II; Burnley, P. C.

    2015-12-01

    Bastnaesite (Ce,La,Y)CO3(F,OH) is a rare earth element (REE) bearing ore mineral. REEs are more common in the Earth's crust than precious metals like gold or platinum, but are not commonly concentrated in economically viable ore deposits. For over a decade, China has been the world's leading supplier of REEs. Recent export restrictions from China have necessitated the search for new deposits. Determining basic material properties such as phase equilibria and the equation of state for bastnaesite helps in understanding the processes that form REE ore deposits and thereby assist in locating new deposits. For this study we focus on the lanthanum-fluoride variant of bastnaesite (LaCO3F) since it can be easily synthesized in the laboratory. Previous work by others determined that in both open and closed systems at atmospheric pressure bastnaesite decomposes to lanthanum oxyfluoride and carbon dioxide (LaOF + CO2) above 325°C; at 100 MPa bastnaesite decomposes above 860°C (Hsu, 1992). Using a Griggs-type modified piston cylinder apparatus, we pressurized samples of synthetic bastnaesite-(La) to conditions ranging from 250 MPa to 1.2 GPa, and then subjected each sample to constant temperatures ranging from 700°C to 1050°C for a minimum of five hours. We then analyzed the samples with X-ray powder diffraction to identify phases present and determined that bastnaesite-(La) is stable at 250 MPa up to approximately 800°C and at 1.0 GPa up to approximately 900°C. Reversal experiments are underway. In order to develop an equation of state for bastnaesite-(La), we studied single crystals via monochromatic synchrotron X-ray diffraction in the diamond anvil cell at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. Measurements were made at pressures ranging from ambient to nearly 4 GPa. From these diffraction patterns, we determine the structure of bastnaesite-(La), and the change in unit cell volume as a function of pressure can be fit to a Birch

  19. Using a Differential Scanning Calorimeter to Teach Phase Equilibria to Students of Igneous and Metamorphic Petrology

    Science.gov (United States)

    Maria, Anton H.; Millam, Evan L.; Wright, Carrie L.

    2011-01-01

    As an aid for teaching phase equilibria to undergraduate students of igneous and metamorphic petrology, we have designed a laboratory exercise that allows them to create a phase diagram from data produced by differential scanning calorimetry. By preparing and analyzing samples of naphthalene and phenanthrene, students acquire hands-on insight into…

  20. New investigation of phase equilibria in the system Al-Cu-Si.

    Science.gov (United States)

    Ponweiser, Norbert; Richter, Klaus W

    2012-01-25

    The phase equilibria and invariant reactions in the system Al-Cu-Si were investigated by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe micro analysis (EPMA). Isothermal phase equilibria were investigated within two isothermal sections. The isothermal section at 500 °C covers the whole ternary composition range and largely confirms the findings of previous phase diagram investigations. The isothermal section at 700 °C describes phase equilibria only in the complex Cu-rich part of the phase diagram. A new ternary compound τ was found in the region between (Al,Cu)-γ(1) and (Cu,Si)-γ and its solubility range was determined. The solubility of Al in κ-CuSi was found to be extremely high at 700 °C. In contrast, no ternary solubility in the β-phase of Cu-Al was found, although this phase is supposed to form a complete solid solution according to previous phase diagram assessments. Two isopleths, at 10 and 40 at.% Si, were investigated by means of DTA and a partial ternary reaction scheme (Scheil diagram) was constructed, based on the current work and the latest findings in the binary systems Al-Cu and Cu-Si. The current study shows that the high temperature equilibria in the Cu-rich corner are still poorly understood and additional studies in this area would be favorable.

  1. Isothermal phase equilibria for the (HFC-32 + HFC-134a) mixed-gas hydrate system

    International Nuclear Information System (INIS)

    Miyauchi, Hiroshi; Yasuda, Kenjiro; Matsumoto, Yuuki; Hashimoto, Shunsuke; Sugahara, Takeshi; Ohgaki, Kazunari

    2012-01-01

    Highlights: ► Structural phase transition results in the heterogeneous azeotropic-like behaviour. ► HFC-134a molecules, in spite of an s-II former, occupy the large cages of s-I. ► Negative azeotropic-like behaviour becomes more remarkable at higher temperatures. - Abstract: Isothermal phase equilibria (pressure-composition relations in hydrate, gas, and aqueous phases) in the {difluoromethane (HFC-32) + 1,1,1,2-tetrafluoroethane (HFC-134a)} mixed-gas hydrate system were measured at the temperatures 274.15 K, 279.15 K, and 283.15 K. The heterogeneous azeotropic-like behaviour derived from the structural phase transition of (HFC-32 + HFC-134a) mixed-gas hydrates appears over the whole temperature range of the present study. In addition to the heterogeneous azeotropic-like behaviour, the isothermal phase equilibrium curves of the (HFC-32 + HFC-134a) mixed-gas hydrate system exhibit the negative homogeneous azeotropic-like behaviour at temperatures 279.15 K and 283.15 K. The negative azeotropic-like behaviour, which becomes more remarkable at higher temperatures, results in the lower equilibrium pressure of (HFC-32 + HFC-134a) mixed-gas hydrates than those of both simple HFC-32 and HFC-134a hydrates. Although the HFC-134a molecule forms the simple structure-II hydrate at the temperatures, the present findings reveal that HFC-134a molecules occupy a part of the large cages of the structure-I mixed-gas hydrate.

  2. Development and testing of a new apparatus for the measurement of high-pressure low-temperature phase equilibria

    DEFF Research Database (Denmark)

    Fonseca, José M.S.; von Solms, Nicolas

    2012-01-01

    A new apparatus for the study of high-pressure phase equilibria at low temperatures using an analytical method was designed, assembled and tested. The apparatus was specially developed for the study of multi-phase equilibria in systems containing hydrocarbons, water and hydrate inhibitors, at tem...

  3. Systematic identification method for data analysis and phase equilibria modelling for lipids systems

    DEFF Research Database (Denmark)

    Perederic, Olivia A.; Cunico, Larissa P.; Kalakul, Sawitree

    2018-01-01

    Industrial use of lipids has been increasing as a consequence of increased developments related to biobased economies. In addition to applications in food-products, lipids are used by many industrial sectors, for example, biodiesel, edible oil, health, and personal care. Phase equilibria...

  4. Phase equilibria, phases and compounds in the Ti-C system

    International Nuclear Information System (INIS)

    Gusev, Aleksandr I

    2002-01-01

    The results of experimental and theoretical investigations of the phase equilibria in the titanium-carbon system are generalised. The generalised thermodynamic characteristics of disordered titanium carbide TiC y , are reported. Peculiarities of the crystal structures of all the known and hypothetical compounds of titanium with carbon are considered in detail. The X-ray diffraction patterns which allow identification of all these compounds are presented. The phase diagrams of the Ti-C system constructed with allowance for atomic ordering of non-stoichio metric carbide, TiC y , and for the existence of the molecular cluster-like compounds Ti 8 C 12 and Ti 13 C 22 (TiC 2 ) are discussed. The bibliography includes 142 references.

  5. Phase equilibria, phases and compounds in the Ti-C system

    International Nuclear Information System (INIS)

    Gusev, A.I.

    2002-01-01

    The results of experimental and theoretical investigations related to the phase equilibria in the titanium-carbon system are generalized. The generalized thermodynamic characteristics of the disordered titanium carbide TiC y are given. The crystal structure of all the discovered and hypothetical compounds of titanium with carbon are considered in detail. The x-ray diffraction patterns which allow one to identify all these compounds are given. The phase diagrams of the Ti-C system constructed with allowance for atomic ordering of non-stoichiometric TiC y carbide and for the existence of the compounds Ti 8 C 12 and Ti 13 C 22 (TiC 2 ) of the molecule cluster type are discussed [ru

  6. Experimental investigation of phase equilibria in the Ni-Nb-V ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Yang, Shuiyuan; Wang, Cuiping [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Fujian Provincial Key Lab. of Materials Genome; Zhang, Xianjie; Jiang, Hengxing; Shi, Zhan [Xiamen Univ. (China). Dept. of Materials Science and Engineering

    2017-09-15

    The phase equilibria of the Ni-Nb-V ternary system at 1000 C and 1200 C were established using electron probe microanalysis, X-ray diffraction and differential scanning calorimetry. The results of the investigation revealed that: (1) The Nb solubility in (Ni) and σ{sup '} phases was less than 10 at.%; (2) A ternary compound τ (NiNbV) was confirmed, in which V had a large solubility; (3) A new liquid region was evident at 1200 C, but was absent at 1000 C; (4) The lattice constants of Ni{sub 3}Nb and Ni{sub 6}Nb{sub 7} phase decreased with increase in V content in the Ni{sub 3}Nb and Ni{sub 6}Nb{sub 7}. The phase equilibria of the Ni-Nb-V ternary system will contribute to its thermodynamic assessment.

  7. Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

    International Nuclear Information System (INIS)

    Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun

    2017-01-01

    The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr 7 Ni 10 , ZrNi, ZrNi 5 , Zr 14 Cu 51 , and Zr 2 Cu 9 , show a remarkable ternary solubility. A new ternary compound named τ 3 (Zr 31.1-30.7 . Cu 28.5-40.3 Ni 40.4-29.0 ) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

  8. Thermodynamic calculations in the system CH4-H2O and methane hydrate phase equilibria

    Science.gov (United States)

    Circone, S.; Kirby, S.H.; Stern, L.A.

    2006-01-01

    Using the Gibbs function of reaction, equilibrium pressure, temperature conditions for the formation of methane clathrate hydrate have been calculated from the thermodynamic properties of phases in the system CH4-H 2O. The thermodynamic model accurately reproduces the published phase-equilibria data to within ??2 K of the observed equilibrium boundaries in the range 0.08-117 MPa and 190-307 K. The model also provides an estimate of the third-law entropy of methane hydrate at 273.15 K, 0.1 MPa of 56.2 J mol-1 K-1 for 1/n CH4??H 2O, where n is the hydrate number. Agreement between the calculated and published phase-equilibria data is optimized when the hydrate composition is fixed and independent of the pressure and temperature for the conditions modeled. ?? 2006 American Chemical Society.

  9. High-pressure phase equilibria in the (carbon dioxide + 1-hexanol) system

    International Nuclear Information System (INIS)

    Secuianu, Catinca; Feroiu, Viorel; Geana, Dan

    2010-01-01

    (Vapour + liquid) equilibria (VLE) and (vapour + liquid + liquid) equilibria (VLLE) data for the (carbon dioxide + 1-hexanol) system were measured at (293.15, 303.15, 313.15, 333.15, and 353.15) K. Phase behaviour measurements were made in a high-pressure visual cell with variable volume, based on the static-analytic method. The pressure range under investigation was between (0.6 and 14.49) MPa. The Soave-Redlich-Kwong (SRK) equation of state (EOS) with classical van der Waals mixing rules (two-parameters conventional mixing rule, 2PCMR), was used in a semi-predictive approach, in order to represent the complex phase behaviour (critical curve, LLV line, isothermal VLE, LLE, and VLLE) of the system. The topology of phase behaviour is reasonably well predicted.

  10. Phase equilibria in Ca–Co–O system

    Czech Academy of Sciences Publication Activity Database

    Sedmidubský, D.; Jakeš, V.; Jankovský, O.; Leitner, J.; Šofer, Z.; Hejtmánek, Jiří

    2012-01-01

    Roč. 194, OCT (2012), s. 199-205 ISSN 0022-4596 R&D Projects: GA ČR GA203/09/1036 Institutional research plan: CEZ:AV0Z10100521 Keywords : Ca–Co–O system , Misfit cobaltites, Thermodynamic data, Phase diagrams * misfit cobaltites * thermodynamic data * phase diagrams Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.040, year: 2012

  11. Generalized thermodynamics of phase equilibria in scalar active matter

    Science.gov (United States)

    Solon, Alexandre P.; Stenhammar, Joakim; Cates, Michael E.; Kafri, Yariv; Tailleur, Julien

    2018-02-01

    Motility-induced phase separation (MIPS) arises generically in fluids of self-propelled particles when interactions lead to a kinetic slowdown at high densities. Starting from a continuum description of scalar active matter akin to a generalized Cahn-Hilliard equation, we give a general prescription for the mean densities of coexisting phases in flux-free steady states that amounts, at a hydrodynamics scale, to extremizing an effective free energy. We illustrate our approach on two well-known models: self-propelled particles interacting either through a density-dependent propulsion speed or via direct pairwise forces. Our theory accounts quantitatively for their phase diagrams, providing a unified description of MIPS.

  12. Ab initio study of phase equilibria in TiCx

    DEFF Research Database (Denmark)

    Korzhavyi, P.A.; Pourovskii, L.V.; Hugosson, H.W.

    2002-01-01

    The phase diagram for the vacancy-ordered structures in the substoichiometric TiCx (x = 0.5-1.0) has been established from Monte Carlo simulations with the long-range pair and multisite effective interactions obtained from ab initio calculations. Three ordered superstructures of vacancies (Ti2C, Ti...

  13. Boron incorporation into rutile: phase equilibria and structural considerations

    International Nuclear Information System (INIS)

    Grey, I.E.; Li, C.; MacRae, C.M.; Bursill, L.A.

    1997-01-01

    Reduction of rutile in the presence of borate flux stabilised the rutile phase relative to reduced rutiles due to incorporation of boron from the flux. In the presence of borates the rutile phase is stabilised to oxygen fugacities that are lower by almost two orders of magnitude compared with fugacities at the limit of the single-phase rutile phase field in the pure Ti-O system. Boron incorporation is accompanied by reduction of titanium to the trivalent state, according to the charge compensation relation: 3Ti 4+ ≡ 3 Ti 3+ + B 3+ . Results of powder X-ray diffraction and transmission electron microscopy studies on samples prepared in the temperature range 1100 to 1300 deg C have been used to establish a model for boron incorporation. It is proposed that at the temperatures studied, local defects in boron doped rutile result from displacement of titanium atoms to adjacent interstitial sites coupled with occupation by boron of the triangular face of the vacated octahedral sites. This atomic grouping represents a small element of the TiBO 3 (calcite-type) structure. Annealing at a lower temperature results in ordering of the local defects to form (101) r planar intergrowths of rutile and calcite-type structures. 14 refs., 3 tabs., 8 figs

  14. Boron incorporation into rutile: phase equilibria and structural considerations

    Energy Technology Data Exchange (ETDEWEB)

    Grey, I.E.; Li, C.; MacRae, C.M. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), East Melbourne, VIC (Australia). Div of Minerals; Bursill, L.A. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-06-01

    Reduction of rutile in the presence of borate flux stabilised the rutile phase relative to reduced rutiles due to incorporation of boron from the flux. In the presence of borates the rutile phase is stabilised to oxygen fugacities that are lower by almost two orders of magnitude compared with fugacities at the limit of the single-phase rutile phase field in the pure Ti-O system. Boron incorporation is accompanied by reduction of titanium to the trivalent state, according to the charge compensation relation: 3Ti{sup 4+}{identical_to} 3 Ti{sup 3+} + B{sup 3+}. Results of powder X-ray diffraction and transmission electron microscopy studies on samples prepared in the temperature range 1100 to 1300 deg C have been used to establish a model for boron incorporation. It is proposed that at the temperatures studied, local defects in boron doped rutile result from displacement of titanium atoms to adjacent interstitial sites coupled with occupation by boron of the triangular face of the vacated octahedral sites. This atomic grouping represents a small element of the TiBO{sub 3} (calcite-type) structure. Annealing at a lower temperature results in ordering of the local defects to form (101){sub r} planar intergrowths of rutile and calcite-type structures. 14 refs., 3 tabs., 8 figs.

  15. Direct phase coexistence molecular dynamics study of the phase equilibria of the ternary methane-carbon dioxide-water hydrate system.

    Science.gov (United States)

    Michalis, Vasileios K; Tsimpanogiannis, Ioannis N; Stubos, Athanassios K; Economou, Ioannis G

    2016-09-14

    Molecular dynamics simulation is used to predict the phase equilibrium conditions of a ternary hydrate system. In particular, the direct phase coexistence methodology is implemented for the determination of the three-phase coexistence temperature of the methane-carbon dioxide-water hydrate system at elevated pressures. The TIP4P/ice, TraPPE-UA and OPLS-UA forcefields for water, carbon dioxide and methane respectively are used, in line with our previous studies of the phase equilibria of the corresponding binary hydrate systems. The solubility in the aqueous phase of the guest molecules of the respective binary and ternary systems is examined under hydrate-forming conditions, providing insight into the predictive capability of the methodology as well as the combination of these forcefields to accurately describe the phase behavior of the ternary system. The three-phase coexistence temperature is calculated at 400, 1000 and 2000 bar for two compositions of the methane-carbon dioxide mixture. The predicted values are compared with available calculations with satisfactory agreement. An estimation is also provided for the fraction of the guest molecules in the mixed hydrate phase under the conditions examined.

  16. Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag system

    Directory of Open Access Journals (Sweden)

    Živković D.

    2011-01-01

    Full Text Available Ternary Pb-Zn-Ag system is typical for some physicochemical processes going on in refining phase in the extractive metallurgy of lead. Therefore, investigation of mentioned system is important from both theoretical and practical research of the phenomena occurring during the lead desilverizing process. The results of experimental investigation using differential thermal analysis (DTA and thermodynamic calculation of phase equilibria in Pb-Zn-Ag system according to CALPHAD method, in the sections with Zn:Ag mass ratio equal to 90:10, 70:30 and 50:50, are presented in this paper.

  17. Corium phase equilibria based on MASCA, METCOR and CORPHAD results

    Energy Technology Data Exchange (ETDEWEB)

    Bechta, S.V.; Granovsky, V.S.; Khabensky, V.B. [Alexandrov Research Institute of Technologies (NITI), Sosnovy Bor (Russian Federation); Gusarov, V.V.; Almiashev, V.I.; Mezentseva, L.P. [Grebenshikov Institute of Silicate Chemistry, Russian Academy of Sciences (ISCh RAS), St. Petersburg (Russian Federation); Krushinov, E.V.; Kotova, S.Yu.; Kosarevsky, R.A. [Alexandrov Research Institute of Technologies (NITI), Sosnovy Bor (Russian Federation); Barrachin, M. [Institut de Radioprotection et Surete Nucleaire IRSN/DPAM, St Paul lez Durance (France); Bottomley, D. [EUROPAISCHE KOMMISSION, Joint Research Centre Institut fuer Transurane (ITU), Karlsruhe (Germany); Fichot, F. [Institut de Radioprotection et Surete Nucleaire IRSN/DPAM, St Paul lez Durance (France); Fischer, M. [AREVA NP GmbH, Erlangen (Germany)], E-mail: Manfred.Fischer@areva.com

    2008-10-15

    Experimental data on component partitioning between suboxidized corium melt and steel in the in-vessel melt retention (IVR) conditions are compared. The data are produced within the OECD MASCA program and the ISTC CORPHAD project under close-to-isothermal conditions and in the ISTC METCOR project under thermal gradient conditions. Chemical equilibrium in the U-Zr-Fe(Cr,Ni,...)-O system is reached in all experiments. In MASCA tests the molten pool formed under inert atmosphere has two immiscible liquids, oxygen-enriched (oxidic) and oxygen-depleted (metallic), resulting of the miscibility gap of the mentioned system. Sub-system data of the U-Zr-Fe(Cr,Ni,...)-O phase diagram investigated within the ISTC CORPHAD project are interpreted in relation with the MASCA results. In METCOR tests the equilibrium is established between oxidic liquid and mushy metallic part of the system. Results of comparison are discussed and the implications for IVR noted.

  18. The prediction and representation of phase equilibria and physicochemical properties in complex coal ash slag systems

    Energy Technology Data Exchange (ETDEWEB)

    E. Jak; A. Kondratiev; S. Christie; P.C. Hayes [Centre for Coal in Sustainable Development (CCSD), Brisbane (Australia)

    2003-07-01

    A range of problems in coal utilisation technologies, including ash slag flow in slagging gasifiers, deposit formation, slagging, fouling, fusibility tests, fluxing, blending etc, are related to the melting behaviour of the mineral matter in the coal. To assist with solving these practical issues i) thermodynamic modelling of phase equilibria, and ii) viscosity modelling studies are being undertaken at the Pyrometallurgy Research Centre (The University of Queensland, Australia) with support from the Collaborative Research Centre for Coal in Sustainable Development (CCSD). The thermodynamic modelling has been carried out using the computer system FactSage, which is used for the calculation of multi-phase slag / solid / gas / matte / alloy / salt equilibria in multi-component systems of industrial interest. A modified quasi-chemical solution model is used for the liquid slag phase. New model optimisations have been carried out, which have significantly improved the accuracy of the thermodynamic models for coal combustion processes. Viscosity modelling, using a modified Urbain formalism, is carried out in conjunction with FactSage calculations to predict the viscosities of fully liquid as well as heterogeneous, partly crystallised slags. Custom designed software packages are developed using these fundamental models for wider use by industrial researchers and engineers, and for incorporation as process control modules. The new custom-designed computer software package can be used to produce limiting operability diagrams for slag systems. These diagrams are used to describe phase equilibria and physico-chemical properties in complex slag systems. The approach is illustrated with calculations on the system SiO{sub 2}-Al{sub 2}O{sub 3}-FeO-Fe{sub 2}O{sub 3}-CaO at metallic iron saturation, slags produced in coal slagging gasifiers. 28 refs., 7 figs., 1 tab.

  19. Thermodynamic calculation of phase equilibria of the U-Ga and U-W systems

    International Nuclear Information System (INIS)

    Wang, J.; Liu, X.J.; Wang, C.P.

    2008-01-01

    The thermodynamic assessments of the U-Ga and U-W systems have been carried out by using the CALPHAD (calculation of phase diagrams) method using experimental data including thermodynamic properties and phase equilibria. Gibbs free energies of the solution phases were described by the subregular solution models with the Redlich-Kister equation, and those of the intermetallic compounds were described by the sublattice models. A consistent set of thermodynamic parameters has been derived for the Gibbs free energy of each phase in the U-Ga and U-W binary systems, respectively. The calculated phase diagrams and thermodynamic properties in the U-Ga and U-W systems are in good agreement with experimental data

  20. Prediction of phase equilibria in the In–Sb–Pb system

    Directory of Open Access Journals (Sweden)

    DUSKO MINIC

    2008-03-01

    Full Text Available Binary thermodynamic data, successfully used for phase diagram calculations of the binary systems In–Sb, Pb–Sb and In–Pb, were used for the prediction of the phase equilibria in the ternary In–Sb–Pb system. The predicted equilibrium phase diagram of the vertical Pb–InSb section was compared with the results of differential thermal analysis DTA and optical microscopy. The calculated phase diagram of the isothermal section at 300 °C was compared with the experimentally (SEM, EDX determined composition of phases in the chosen alloys after annealing. Very good agreement between the binary-based thermodynamic prediction and the experimental data was found in all cases. The calculated liquidus projection of the ternary In–Sb–Pb system is also presented.

  1. Experimental investigation of phase equilibria in the Nb-Si-Ta ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Wang, Cuiping; Yao, Jun; Yang, Shuiyuan; Zhan Shi; Liu, Xingjun [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Fujian Provincial Key Laboratory of Materials Genome; Kang, Yongwang [Beijing Institute of Aeronautical Materials (China). Science and Technology on Advanced High Temperature Structural Materials Lab.

    2016-12-15

    The phase equilibria in the Nb-Si-Ta ternary system at 1 373 K, 1 473 K and 1 573 K were investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction. The isothermal sections at 1 373 K, 1 473 K and 1 573 K consist of two three-phase regions and seven two-phase regions, without any ternary compounds. The compounds of NbSi{sub 2} and TaSi{sub 2}, αNb{sub 5}Si{sub 3} and αTa{sub 5}Si{sub 3} form continuous solid solutions, respectively. The solubilities of Nb in Ta{sub 3}Si and Ta{sub 2}Si phases are extremely large, whereas the solubility of Si in the β(Nb, Ta) phase is relatively small.

  2. Experimental investigation of phase equilibria in the Co-W-V ternary system

    International Nuclear Information System (INIS)

    Liu Xingjun; Zhu Yihong; Yu Yan; Wang Cuiping

    2011-01-01

    Highlights: → Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined. → No ternary compound was found in the Co-W-V ternary system. → A stable liquid miscibility gap is newly discovered in the Co-W-V ternary system. → This work is of great essence to establish the thermodynamic database for the Co-based alloys. - Abstract: The phase equilibria in the Co-W-V ternary system were experimentally investigated by optical microscopy (OM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined, and no ternary compound was found in this system. In addition, a novel phenomena induced by the liquid phase separation in the Co-W-V alloys was firstly discovered, suggesting that a stable liquid miscibility gap exists in the Co-W-V ternary system. The newly determined phase equilibria and firstly discovered phase separation phenomena in the Co-W-V system will provide important information for the development of Co-W based alloys.

  3. Benzimidazole acrylonitriles as multifunctional push-pull chromophores: Spectral characterisation, protonation equilibria and nanoaggregation in aqueous solutions

    Science.gov (United States)

    Horak, Ema; Vianello, Robert; Hranjec, Marijana; Krištafor, Svjetlana; Zamola, Grace Karminski; Steinberg, Ivana Murković

    2017-05-01

    Heterocyclic donor-π-acceptor molecular systems based on an N,N-dimethylamino phenylacrylonitrile benzimidazole skeleton have been characterised and are proposed for potential use in sensing applications. The benzimidazole moiety introduces a broad spectrum of useful multifunctional properties to the system including electron accepting ability, pH sensitivity and compatibility with biomolecules. The photophysical characterisation of the prototropic forms of these chromophores has been carried out in both solution and on immobilisation in polymer films. The experimental results are further supported by computational determination of pKa values. It is noticed that compound 3 forms nanoaggregates in aqueous solutions with aggregation-induced emission (AIE) at 600 nm. All the systems demonstrate spectral pH sensitivity in acidic media which shifts towards near-neutral values upon immobilisation in polymer films or upon aggregation in an aqueous environment (compound 3). The structure-property relationships of these functional chromophores, involving their spectral characteristics, acid-base equilibria, pKa values and aggregation effects have been determined. Potential applications of the molecules as pH and biomolecular sensors are proposed based on their pH sensitivity and AIE properties.

  4. Phases, phase equilibria, and phase rules in low-dimensional systems

    International Nuclear Information System (INIS)

    Frolov, T.; Mishin, Y.

    2015-01-01

    We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality

  5. Solid-liquid phase equilibria of Fe-Cr-Al alloys and spinels

    Science.gov (United States)

    McMurray, J. W.; Hu, R.; Ushakov, S. V.; Shin, D.; Pint, B. A.; Terrani, K. A.; Navrotsky, A.

    2017-08-01

    Ferritic FeCrAl alloys are candidate accident tolerant cladding materials. There is a paucity of data concerning the melting behavior for FeCrAl and its oxides. Analysis tools have therefore had to utilize assumptions for simulations using FeCrAl cladding. The focus of this study is to examine in some detail the solid-liquid phase equilibria of FeCrAl alloys and spinels with the aim of improving the accuracy of severe accident scenario computational studies.

  6. Phase equilibria of didecyldimethylammonium nitrate ionic liquid with water and organic solvents

    International Nuclear Information System (INIS)

    Domanska, Urszula; Lugowska, Katarzyna; Pernak, Juliusz

    2007-01-01

    The phase diagrams for binary mixtures of an ammonium ionic liquid, didecyldimethylammonium nitrate, [DDA][NO 3 ], with: alcohols (propan-1-ol, butan-1-ol, octan-1-ol, and decan-1-ol): hydrocarbons (toluene, propylbenzene, hexane, and hexadecane) and with water were determined in our laboratory. The phase equilibria were measured by a dynamic method from T 220 K to either the melting point of the ionic liquid, or to the boiling point of the solvent. A simple liquidus curve in a eutectic system was observed for [DDA][NO 3 ] with: alcohols (propan-1-ol, butan-1-ol, and octan-1-ol); aromatic hydrocarbons (toluene and propylbenzene) and with water. (Solid + liquid) equilibria with immiscibility in the liquid phase were detected with the aliphatic hydrocarbons heptane and hexadecane and with decan-1-ol. (Liquid + liquid) equilibria for the system [DDA][NO 3 ] with hexadecane was observed for the whole mole fraction range of the ionic liquid. The observation of the upper critical solution temperature in binary mixtures of ([DDA][NO 3 ] + decan-1-ol, heptane, or hexadecane) was limited by the boiling temperature of the solvent. Characterisation and purity of the compounds were determined by elemental analysis, water content (Fisher method) and differential scanning microcalorimetry (d.s.c.) analysis. The d.s.c. method of analysis was used to determine melting temperatures and enthalpies of fusion. The thermal stability of the ionic liquid was resolved by the thermogravimetric technique-differential thermal analysis (TG-DTA) technique over a wide temperature range from (200 to 780) K. The thermal decomposition temperature of 50% of the sample was greater than 500 K. The (solid + liquid) phase equilibria, curves were correlated by means of different G Ex models utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular system and the particular

  7. Computed phase equilibria for burnable neutron absorbing materials for advanced pressurized heavy water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Corcoran, E.C. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000, St. Forces, Kingston, Ont., K7K 7B4 (Canada)], E-mail: emily.corcoran@rmc.ca; Lewis, B.J.; Thompson, W.T. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000, St. Forces, Kingston, Ont., K7K 7B4 (Canada); Hood, J. [Atomic Energy of Canada Ltd., Sheridan Park, 2251 Speakman Drive, Mississauga, Ont., L5K 1B2 (Canada); Akbari, F.; He, Z. [Atomic Energy of Canada Ltd., Chalk River Laboratories, Chalk River, Ont., K0J 1J0 (Canada); Reid, P. [Atomic Energy of Canada Ltd., Sheridan Park, 2251 Speakman Drive, Mississauga, Ont., L5K 1B2 (Canada)

    2009-03-31

    Burnable neutron absorbing materials are expected to be an integral part of the new fuel design for the Advanced CANDU [CANDU is as a registered trademark of Atomic Energy of Canada Limited.] Reactor. The neutron absorbing material is composed of gadolinia and dysprosia dissolved in an inert cubic-fluorite yttria-stabilized zirconia matrix. A thermodynamic model based on Gibbs energy minimization has been created to provide estimated phase equilibria as a function of composition and temperature. This work includes some supporting experimental studies involving X-ray diffraction.

  8. Phase equilibria in Dy-Cu-Al system at 500 deg C

    International Nuclear Information System (INIS)

    Kuz'ma, Yu.B.; Milyan, V.V.

    1989-01-01

    Using the methods of X-ray diffraction analysis a diagram of phase equilibria in Dy-Cu-Al system at 500 deg C is plotted. Boundaries of solid solutions on the basis of DyCu 2 , DyCu and DyAl 2 compounds are determined and homogeneity regions of ternary compounds Dy 2 (Cu, Al) 7 and Dy(CuAl) 5 are ascertained. Compounds DyCuAl 3 , Dy 4 Cu 4 Al 11 and Dy 5 Cu 6 Al 9 have been detected for the first time

  9. Experimental study of the Cu-Al-Sn phase equilibria, close to the copper zone

    Directory of Open Access Journals (Sweden)

    Soares D.F.

    2017-01-01

    Full Text Available The ternary Cu-Al-Sn phase diagram is the base for several important types of alloys, with relevant industrial interest and applications. The knowledge of the melting/solidification alloys characteristics are determinant for their preparation and properties control. However, there is a lack of experimental information on the ternary phase diagram, at high temperature. In this work, several alloys, with high copper content and additions of Al, up to 10%, and Sn, up to 14% (in wt%, were studied by thermal analysis and by isothermal phase equilibria determination. The alloys liquidus and solidus lines and the binary α + β phase field, at 800°C, are presented for the studied range of compositions.

  10. Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun [Xiamen Univ. (China). College of Materials and Fujian Provincial Key Lab. of Materials Genome

    2017-08-15

    The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr{sub 7}Ni{sub 10}, ZrNi, ZrNi{sub 5}, Zr{sub 14}Cu{sub 51}, and Zr{sub 2}Cu{sub 9}, show a remarkable ternary solubility. A new ternary compound named τ{sub 3} (Zr{sub 31.1-30.7} . Cu{sub 28.5-40.3}Ni{sub 40.4-29.0}) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

  11. Evaluation of Thermodynamic Models for Predicting Phase Equilibria of CO2 + Impurity Binary Mixture

    Science.gov (United States)

    Shin, Byeong Soo; Rho, Won Gu; You, Seong-Sik; Kang, Jeong Won; Lee, Chul Soo

    2018-03-01

    For the design and operation of CO2 capture and storage (CCS) processes, equation of state (EoS) models are used for phase equilibrium calculations. Reliability of an EoS model plays a crucial role, and many variations of EoS models have been reported and continue to be published. The prediction of phase equilibria for CO2 mixtures containing SO2, N2, NO, H2, O2, CH4, H2S, Ar, and H2O is important for CO2 transportation because the captured gas normally contains small amounts of impurities even though it is purified in advance. For the design of pipelines in deep sea or arctic conditions, flow assurance and safety are considered priority issues, and highly reliable calculations are required. In this work, predictive Soave-Redlich-Kwong, cubic plus association, Groupe Européen de Recherches Gazières (GERG-2008), perturbed-chain statistical associating fluid theory, and non-random lattice fluids hydrogen bond EoS models were compared regarding performance in calculating phase equilibria of CO2-impurity binary mixtures and with the collected literature data. No single EoS could cover the entire range of systems considered in this study. Weaknesses and strong points of each EoS model were analyzed, and recommendations are given as guidelines for safe design and operation of CCS processes.

  12. Sn-In-Ag phase equilibria and Sn-In-(Ag)/Ag interfacial reactions

    International Nuclear Information System (INIS)

    Chen Sinnwen; Lee Wanyu; Hsu Chiaming; Yang Chingfeng; Hsu Hsinyun; Wu Hsinjay

    2011-01-01

    Research highlights: → Thermodynamic models of Sn-In and Sn-In-Ag are developed using the CALPHAD approach. → Reaction layer in the Sn-In-(Ag)/Ag couples at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. → Reactions in the Sn-20 wt%In-2.8 wt%Ag/Ag couples are faster than those in the Sn-20 wt%In/Ag couples. - Abstract: Experimental verifications of the Sn-In and Sn-In-Ag phase equilibria have been conducted. The experimental measurements of phase equilibria and thermodynamic properties are used for thermodynamic modeling by the CALPHAD approach. The calculated results are in good agreement with experimental results. Interfacial reactions in the Sn-In-(Ag)/Ag couples have been examined. Both Ag 2 In and AgIn 2 phases are formed in the Sn-51.0 wt%In/Ag couples reacted at 100 and 150 deg. C, and only the Ag 2 In phase is formed when reacted at 25, 50 and 75 deg. C. Due to the different growth rates of different reaction phases, the reaction layer at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. In the Sn-20.0 wt%In/Ag couples, the ζ phase is formed at 250 deg. C and ζ/AgIn 2 phases are formed at 125 deg. C. Compared with the Sn-20 wt%In/Ag couples, faster interfacial reactions are observed in the Sn-20.0 wt%In-2.8 wt%Ag/Ag couples, and minor Ag addition to Sn-20 wt%In solder increases the growth rates of the reaction phases.

  13. Another dimension to metamorphic phase equilibria: the power of interactive movies for understanding complex phase diagram sections

    Science.gov (United States)

    Moulas, E.; Caddick, M. J.; Tisato, N.; Burg, J.-P.

    2012-04-01

    The investigation of metamorphic phase equilibria, using software packages that perform thermodynamic calculations, involves a series of important assumptions whose validity can often be questioned but are difficult to test. For example, potential influences of deformation on phase relations, and modification of effective reactant composition (X) at successive stages of equilibrium may both introduce significant uncertainty into phase diagram calculations. This is generally difficult to model with currently available techniques, and is typically not well quantified. We present here a method to investigate such phenomena along pre-defined Pressure-Temperature (P-T) paths, calculating local equilibrium via Gibbs energy minimization. An automated strategy to investigate complex changes in the effective equilibration composition has been developed. This demonstrates the consequences of specified X modification and, more importantly, permits automated calculation of X changes that are likely along the requested path if considering several specified processes. Here we describe calculations considering two such processes and show an additional example of a metamorphic texture that is difficult to model with current techniques. Firstly, we explore the assumption that although water saturation and bulk-rock equilibrium are generally considered to be valid assumptions in the calculation of phase equilibria, the saturation of thermodynamic components ignores mechanical effects that the fluid/melt phase can impose on the rock, which in turn can modify the effective equilibrium composition. Secondly, we examine how mass fractionation caused by porphyroblast growth at low temperatures or progressive melt extraction at high temperatures successively modifies X out of the plane of the initial diagram, complicating the process of determining best-fit P-T paths for natural samples. In particular, retrograde processes are poorly modeled without careful consideration of prograde

  14. Ternary systems Sr-{Ni,Cu}-Si: Phase equilibria and crystal structure of ternary phases

    International Nuclear Information System (INIS)

    Nasir, Navida; Melnychenko-Koblyuk, Nataliya; Grytsiv, Andriy; Rogl, Peter; Giester, Gerald; Wosik, Jaroslaw; Nauer, Gerhard E.

    2010-01-01

    Phase relations were established in the Sr-poor part of the ternary systems Sr-Ni-Si (900 deg. C) and Sr-Cu-Si (800 deg. C) by light optical microscopy, electron probe microanalysis and X-ray diffraction on as cast and annealed alloys. Two new ternary compounds SrNiSi 3 (BaNiSn 3 -type) and SrNi 9-x Si 4+x (own-type) were found in the Sr-Ni-Si system along with previously reported Sr(Ni x Si 1-x ) 2 (AlB 2 -type). The crystal structure of SrNi 9-x Si 4+x (own-type, x=2.7, a=0.78998(3), c=1.1337(2) nm; space group P4/nbm) was determined from X-ray single crystal counter to be a low symmetry derivative of the cubic, parent NaZn 13 -type. At higher Si-content X-ray Rietveld refinements reveal the formation of a vacant site (□) corresponding to a formula SrNi 5.5 Si 6.5 □ 1.0 . Phase equilibria in the Sr-Cu-Si system are characterized by the compounds SrCu 2-x Si 2+x (ThCr 2 Si 2 -type), Sr(Cu x Si 1-x ) 2 (AlB 2 -type), SrCu 9-x Si 4+x (0≤x≤1.0; CeNi 8.5 Si 4.5 -type) and SrCu 13-x Si x (4≤x≤1.8; NaZn 13 -type). The latter two structure types appear within a continuous solid solution. Neither a type-I nor a type-IX clathrate compound was encountered in the Sr-{Cu,Ni}-Si systems. Structural details are furthermore given for about 14 new ternary compounds from related alloy systems with Ba. - Graphical abstract: The crystal structure of SrNi 9-x Si 4+x (own-type, x=2.7, a=0.78998(3), c=1.1337(2) nm; space group P4/nbm) was determined from X-ray single crystal counter to be a low symmetry derivative of the cubic, parent NaZn 13 -type and is related to CeNi 8.5 Si 4.5 -type.

  15. Phase equilibria for mixtures containing very many components. development and application of continuous thermodynamics for chemical process design

    International Nuclear Information System (INIS)

    Cotterman, R.L.; Bender, R.; Prausnitz, J.M.

    1984-01-01

    For some multicomponent mixtures, where detailed chemical analysis is not feasible, the compositio of the mixture may be described by a continuous distribution function of some convenient macroscopic property suc as normal boiling point or molecular weight. To attain a quantitative description of phase equilibria for such mixtures, this work has developed thermodynamic procedures for continuous systems; that procedure is called continuous thermodynamics. To illustrate, continuous thermodynamics is used to calculate dew points for natural-gas mixtures, solvent loss in a high-pressure absorber, and liquid-liquid phase equilibria in a polymer fractionation process. Continuous thermodynamics provides a rational method for calculating phase equilibria for those mixtures where complete chemical analysis is not available but where composition can be given by some statistical description. While continuous thermodynamics is only the logical limit of the well-known pseudo-component method, it is more efficient than that method because it is less arbitrary and it often requires less computer time

  16. Calculation of ethanol refining by means of extractive distillation with water using simulated data on phase equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Rosak, J; Mertl, I; Huml, M; Wichterle, I

    1980-01-01

    Available data on phase equilibria in binary mixtures pertaining to the system ethanol - water - impurities (7 compounds that represent the main impurities present in raw synthetic or fermentation ethanol) have been gathered for the computer calculation of a column to be used for the refining of ethanol. Missing experimental data on phase equilibria were supplied by simulation using the increment method UNIFAC which predicts phase equilibria on the basis of the chemical structure. All data about the behavior of binary mixtures were correlated by means of the NRTL method and the sets of constants thus obtained were then used in calculations of the column for the refining of ethanol. The results were compared with reality verified on industrial scale.

  17. Phase Equilibria Measurement of Binary Mixture for the Propoxylated Neopentyl Glycol Diacrylate in Supercritical Carbon Dioxide

    International Nuclear Information System (INIS)

    Byun, Hun-Soo

    2016-01-01

    Experimental data are reported on the phase equilibrium of propoxylated neopentyl glycol diacrylate in supercritical carbon dioxide. Phase equilibria data were measured in static method at a temperature of (313.2, 333.2, 353.2, 373.2 and 393.2) K and at pressures up to 27.82 MPa. At a constant pressure, the solubility of propoxylated neopentyl glycol diacrylate for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system increases as temperature increases. The (carbon dioxide + propoxylated neopentyl glycol diacrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system is correlated with Peng- Robinson equation of state using mixing rule. The critical property of propoxylated neopentyl glycol diacrylate is predicted with Joback and Lyderson method

  18. Phase Equilibria Measurement of Binary Mixture for the Propoxylated Neopentyl Glycol Diacrylate in Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)

    2016-04-15

    Experimental data are reported on the phase equilibrium of propoxylated neopentyl glycol diacrylate in supercritical carbon dioxide. Phase equilibria data were measured in static method at a temperature of (313.2, 333.2, 353.2, 373.2 and 393.2) K and at pressures up to 27.82 MPa. At a constant pressure, the solubility of propoxylated neopentyl glycol diacrylate for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system increases as temperature increases. The (carbon dioxide + propoxylated neopentyl glycol diacrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system is correlated with Peng- Robinson equation of state using mixing rule. The critical property of propoxylated neopentyl glycol diacrylate is predicted with Joback and Lyderson method.

  19. Prediction of phase equilibria and thermal analysis in the Bi-Cu-Pb ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Manasijevic, Dragan [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Mitovski, Aleksandra, E-mail: amitovski@tf.bor.ac.rs [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Minic, Dusko [University of Pristina, Faculty of Technical Sciences, 38220 Kosovska Mitrovica (Serbia); Zivkovic, Dragana; Marjanovic, Sasa [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia); Todorovic, Radisa [Institute of Mining and Metallurgy, Zeleni Bulevar 35, 19210 Bor (Serbia); Balanovic, Ljubisa [University of Belgrade, Technical Faculty, VJ 12, 19210 Bor (Serbia)

    2010-05-20

    The knowledge about phase diagram of the Bi-Cu-Pb ternary system is of importance in development of copper-lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi-Cu-Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.

  20. Prediction of phase equilibria and thermal analysis in the Bi-Cu-Pb ternary system

    International Nuclear Information System (INIS)

    Manasijevic, Dragan; Mitovski, Aleksandra; Minic, Dusko; Zivkovic, Dragana; Marjanovic, Sasa; Todorovic, Radisa; Balanovic, Ljubisa

    2010-01-01

    The knowledge about phase diagram of the Bi-Cu-Pb ternary system is of importance in development of copper-lead based bearing materials, soldering and in refining of copper and lead. In this work, the phase diagram of the Bi-Cu-Pb ternary system was calculated by the CALPHAD method using binary thermodynamic parameters included in the COST 531 database. The results include liquidus projection, invariant equilibria and three vertical sections with molar ratio Cu:Pb = 1, Cu:Pb = 1:3 and Bi:Cu = 1. Alloys, with compositions along three predicted vertical sections, were measured using differential scanning calorimetry (DSC). The experimentally determined phase transition temperatures were compared with calculated results and good mutual agreement was noticed.

  1. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part II: Binary mixtures with CO2

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2011-01-01

    In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid–liqu...

  2. Phase equilibria and thermodynamic modeling of ethane and propane hydrates in porous silica gels.

    Science.gov (United States)

    Seo, Yongwon; Lee, Seungmin; Cha, Inuk; Lee, Ju Dong; Lee, Huen

    2009-04-23

    In the present study, we examined the active role of porous silica gels when used as natural gas storage and transportation media. We adopted the dispersed water in silica gel pores to substantially enhance active surface for contacting and encaging gas molecules. We measured the three-phase hydrate (H)-water-rich liquid (L(W))-vapor (V) equilibria of C(2)H(6) and C(3)H(8) hydrates in 6.0, 15.0, 30.0, and 100.0 nm silica gel pores to investigate the effect of geometrical constraints on gas hydrate phase equilibria. At specified temperatures, the hydrate stability region is shifted to a higher pressure region depending on pore size when compared with those of bulk hydrates. Through application of the Gibbs-Thomson relationship to the experimental data, we determined the values for the C(2)H(6) hydrate-water and C(3)H(8) hydrate-water interfacial tensions to be 39 +/- 2 and 45 +/- 1 mJ/m(2), respectively. By using these values, the calculation values were in good agreement with the experimental ones. The overall results given in this study could also be quite useful in various fields, such as exploitation of natural gas hydrate in marine sediments and sequestration of carbon dioxide into the deep ocean.

  3. Thermodynamic modelling of phase equilibrium for water + poly(Ethylene glycol + salt aqueous two-phase systems

    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.

  4. Effect of mono-, di- and tri-ethanolammonium tetrafluoroborate protonic ionic liquids on vapour liquid equilibria of ethanol aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Shen Chong [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Ma Xiaoyan [College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Lu Yingzhou [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Li Chunxi, E-mail: Licx@mail.buct.edu.c [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-03-15

    Vapour pressures were measured using a quasi-static ebulliometer for the binary mixture of (water + ethanol) containing one of three protonic ionic liquids (PIL), namely, mono-, di- or tri-ethanolammonium tetrafluoroborate, over the temperature range of (318.24 to 356.58) K at fixed PIL content of 0.30 in mass fraction. The vapour pressure data of the PIL-containing ternary systems were correlated using the NRTL equation with an overall root mean square deviation (RMSD) of 0.0092. The regressed NRTL parameters were used to predict the isobaric vapour liquid equilibria (VLE) for ternary systems (water + ethanol + PIL) at varying mass fraction of PIL and atmospheric pressure (101.3 kPa). It is shown that the effect of PILs on the VLE of the (water + ethanol) mixture follows the order: [HTEA][BF{sub 4}] > [HDEA][BF{sub 4}] > [HMEA][BF{sub 4}]. In addition, the relative volatilities of ethanol to water for pseudo-binary systems (water + ethanol + PIL) were calculated. The results indicate that the PILs studied can enhance the relative volatility of ethanol to water and even break the azeotropic behaviour of ethanol aqueous solution when PIL content is increased to a specified content.

  5. Phase equilibria in TlX-Cd(Zn)X (X-S, Se, Te) systems

    International Nuclear Information System (INIS)

    Gusejnov, F.Kh.; Babanly, M.B.; Kuliev, A.A.

    1982-01-01

    The methods of DTA, RPA and measurement of the alloys microhardness have been used to investigate the phase equilibria in the TlX-Zn(Cd)X systems. It is established that the TlZn(Cd)X 2 compounds, the presence of which is mentioned in the literature earlier, do not form in these systems. The TlSe-Zn(Cd)Se systems apply to the simple eutectic type and characterized by digenerated eutectic near the TlSe. Thermodynamical analysis of the liquidus of the TlSe-CdSe and TlTe-Zn(Cd)Te systems in approximation of the regular solutions, taking into account the dissociation of tallium chalcogenides in liquid phase, is made

  6. Experimental determination of the phase equilibria in the Co-Fe-Zr ternary system

    International Nuclear Information System (INIS)

    Wang, C.P.; Yu, Y.; Zhang, H.H.; Hu, H.F.; Liu, X.J.

    2011-01-01

    Research highlights: → We determined four isothermal sections of the Co-Fe-Zr system from 1000 o C to 1300 o C. → No ternary compound was found in the Co-Fe-Zr ternary system. → The solubility of Fe in the liquid phase at 1300 o C is extremely large. → The (Co, Fe) 2 Zr phase form the continuous solution from Co-Zr side to Fe-Zr side. → The solubility of Zr in the fcc (Co, Fe) phase is extremely small. - Abstract: The phase equilibria in the Co-Fe-Zr ternary system were investigated by means of optical microscopy (OM), electron probe microanalysis (EPMA), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) on equilibrated ternary alloys. Four isothermal sections of the Co-Fe-Zr ternary system at 1300 o C, 1200 o C, 1100 o C and 1000 o C were experimentally established. The experimental results indicate that (1) no ternary compound was found in this system; (2) the solubility of Fe in the liquid phase of the Co-rich corner at 1300 o C is extremely large; (3) the liquid phase in the Zr-rich corner and the (Co,Fe) 2 Zr phase form the continuous solid solutions from the Co-Zr side to the Fe-Zr side; (4) the solubility of Zr in the fcc (Co, Fe) phase is extremely small.

  7. Experimental investigation of the phase equilibria in the Co-Fe-Ti ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chaohui; Chen, Chong; Peng, Yingbiao; Du, Yong; Li, Kun [Central South Univ., State Key of Powder Metallurgy, Changsha (China); Lu, Xingxu [Central South Univ., State Key of Powder Metallurgy, Changsha (China); Central South Univ., School of Materials Science and Engineering, Changsha (China)

    2015-08-15

    Phase equilibria in the Co-Fe-Ti ternary system were investigated by means of the equilibrated alloy method with X-ray powder diffraction and electron probe microanalysis. No ternary compounds were found. The experimental results indicated the existence of seven two-phase and one three-phase regions at 600 C, five two-phase and two three-phase regions at 800 C, and six two-phase and two three-phase regions at 950 C. The solubility of Co in TiFe{sub 2} was determined to be larger than 54 at.% at all investigated temperatures, and the solubilities of Fe in TiCo{sub 3} and Ti{sub 2}Co showed an appreciable increase with increasing temperature. The three-phase equilibrium in the Ti-rich corner at 800 C was revealed to be ((β-Ti) + Ti(Fe, Co) + Ti{sub 2}Co) rather than ((α-Ti) + Ti(Fe, Co) + Ti{sub 2}Co) reported in previous investigations. Based on the experimental data obtained in the present work, three isothermal sections at 600, 800 and 950 C were established.

  8. Experimental investigation of phase equilibria in the Co-Ni-Zr ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Yang, Shuiyuan; Yu, Wenjie; Wang, Cuiping [Xiamen Univ. (China). Fujian Key Laboratory of Materials Genome; Xiong, Huaping; Cheng, Yaoyong; Wu, Xin [Beijing Institute of Aeronautical Materials (China). Div. of Welding and Forging

    2016-10-15

    The phase equilibria of the Co-Ni-Zr ternary system at 1 000 C, 1 100 C and 1 200 C were experimentally investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction on the equilibrated ternary alloys. In this study, no ternary compound is found. The (αCo, Ni) phase region extends from the Ni-rich corner to the Co-rich corner with small solubility of Zr at three sections. At 1 000 C and 1 100 C, Ni{sub 5}Zr, Co{sub 2}Zr and Ni{sub 10}Zr{sub 7} phases have large solid solution ranges, but Ni{sub 10}Zr{sub 7} phase disappears at 1 200 C. The Ni{sub 7}Zr{sub 2}, NiZr, Co{sub 11}Zr{sub 2}, Co{sub 23}Zr{sub 6} and CoZr phases exhibit nearly linear compounds in the studied sections, and have large composition ranges. Additionally, some differences in phase relationship exist among the above three isothermal sections.

  9. Phase equilibria and thermodynamic functions for Ag-Hg and Cu-Hg binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yajun, E-mail: yajunliu@gatech.edu [School of Materials and Energy, Guangdong University of Technology, Guangzhou, Guangdong 510006 (China); Wang, Guan [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou, Guangdong 510006 (China); Wang, Jiang [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Chen, Yang [Mining, Metallurgy and Materials Research Department, General Research Institute for Nonferrous Metals, Beijing 100088 (China); Long, Zhaohui [School of Mechanical Engineering, Xiangtan University, Xiangtan, Hunan 411105 (China)

    2012-11-10

    Highlights: Black-Right-Pointing-Pointer The thermodynamic properties of Ag-Hg and Cu-Hg are explored in order to facilitate dental materials design. Black-Right-Pointing-Pointer A self-consistent set of thermodynamic parameters is obtained. Black-Right-Pointing-Pointer The experimental information can be well reproduced by the optimized thermodynamic data. - Abstract: In order to facilitate the computational design of new amalgams for novel dental alloys, the phase equilibria, phase diagrams and thermodynamic functions for Ag-Hg and Cu-Hg binary systems are explored in this work, based on the CALPHAD framework and experimental characterizations. The Gibbs free energies of the solution phases as well as the stoichiometric phases are calculated, with the aid of enthalpies of mixing, activities, enthalpies of formation, and phase equilibrium data. The thermodynamic descriptions provided in this work enable the stabilities of each phase at various temperatures and compositions to be well described, which contribute to the establishment of a general database to design novel metallic dental materials.

  10. Phase equilibria and thermodynamic functions for Ag–Hg and Cu–Hg binary systems

    International Nuclear Information System (INIS)

    Liu, Yajun; Wang, Guan; Wang, Jiang; Chen, Yang; Long, Zhaohui

    2012-01-01

    Highlights: ► The thermodynamic properties of Ag–Hg and Cu–Hg are explored in order to facilitate dental materials design. ► A self-consistent set of thermodynamic parameters is obtained. ► The experimental information can be well reproduced by the optimized thermodynamic data. - Abstract: In order to facilitate the computational design of new amalgams for novel dental alloys, the phase equilibria, phase diagrams and thermodynamic functions for Ag–Hg and Cu–Hg binary systems are explored in this work, based on the CALPHAD framework and experimental characterizations. The Gibbs free energies of the solution phases as well as the stoichiometric phases are calculated, with the aid of enthalpies of mixing, activities, enthalpies of formation, and phase equilibrium data. The thermodynamic descriptions provided in this work enable the stabilities of each phase at various temperatures and compositions to be well described, which contribute to the establishment of a general database to design novel metallic dental materials.

  11. Experimental investigation of phase equilibria in the Cu–Ni–Si ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Xiang, Shulin; Yang, Shuiyuan; Shi, Rongpei; Wang, Cuiping, E-mail: wangcp@xmu.edu.cn

    2013-11-25

    Highlights: •Three isothermal sections of the Cu–Ni–Si system have been investigated. •The ternary compound τ{sub 1} and the liquid phase are confirmed at 1073 K. •The γ (Cu{sub 5}Si) and θ (Ni{sub 2}Si) phases can be stabilized at higher or lower temperatures. -- Abstract: The phase equilibria in the Cu–Ni–Si ternary system have been investigated experimentally by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis on equilibrated ternary alloys. Three isothermal sections at 1073, 1173 and 1273 K are determined in the whole composition range. The existence of liquid phase and the ternary compound τ{sub 1} is confirmed at 1073 K. The binary γ (Cu{sub 5}Si), γ (Ni{sub 31}Si{sub 12}), δ (Ni{sub 2}Si) and θ (Ni{sub 2}Si) phases exhibit a considerable solubility of a third element. In addition, the γ (Cu{sub 5}Si) and θ (Ni{sub 2}Si) phases can be stabilized by the addition of Ni and Cu, respectively.

  12. Phase equilibria modeling of methanol-containing systems with the CPA and sPC-SAFT equations of state

    DEFF Research Database (Denmark)

    Tybjerg, Peter Chr. V.; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    Proper representation at various conditions of phase equilibria of methanol-containing mixtures (with hydrocarbons, water, etc.) is Important for oil flow assurance purposes In this work two association equations of state. CPA and sPC-SAFT, are applied to methanol-containing mixtures The purpose ...

  13. Modelling of phase equilibria for associating mixtures using an equation of state

    International Nuclear Information System (INIS)

    Ferreira, Olga; Brignole, Esteban A.; Macedo, Eugenia A.

    2004-01-01

    In the present work, the group contribution with association equation of state (GCA-EoS) is extended to represent phase equilibria in mixtures containing acids, esters, and ketones, with water, alcohols, and any number of inert components. Association effects are represented by a group-contribution approach. Self- and cross-association between the associating groups present in these mixtures are considered. The GCA-EoS model is compared to the group-contribution method MHV2, which does not take into account explicitly association effects. The results obtained with the GCA-EoS model are, in general, more accurate when compared to the ones achieved by the MHV2 equation with less number of parameters. Model predictions are presented for binary self- and cross-associating mixtures

  14. Melt-gas phase equilibria and state diagrams of the selenium-tellurium system

    Science.gov (United States)

    Volodin, V. N.; Trebukhov, S. A.; Burabaeva, N. M.; Nitsenko, A. V.

    2017-05-01

    The partial pressures of saturated vapor of the components in the Se-Te system are determined and presented in the form of temperature-concentration dependences from which the boundaries of the melt-gas phase transition are calculated at atmospheric pressure and vacuums of 2000 and 100 Pa. The existence of azeotropic mixtures is revealed. It is found that the points of inseparably boiling melts correspond to 7.5 at % of Se and 995°C at 101325 Pa, 10.9 at % at 673°C and 19.5 at % at 522°C in vacuums of 2000 and 100 Pa, respectively. A complete state diagram is constructed, including the fields of gas-liquid equilibria at atmospheric and low pressures, the boundaries of which allow us to assess the behavior of selenium and tellurium upon distillation fractionation.

  15. Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y-Ba-Co-O system

    OpenAIRE

    Urusova, A. S.; Cherepanov, V. A.; Aksenova, T. V.; Gavrilova, L. Y.; Kiselev, E. A.

    2013-01-01

    The phase equilibria in the Y-Ba-Co-O system were systematically studied at 1373 K in air. The intermediate phases formed in the Y-Ba-Co-O system at 1373 K in air were: YBaCo2O5+δ, YBaCo4O 7 and BaCo1-yYyO3-δ (0.09≤y≤0.42). It was shown that YBaCo2O5+δ possesses tetragonal structure with the 3ap×3a p×2ap superstructure (sp. gr. P4/mmm). High-temperature X-ray diffraction analysis of the YBaCo2O 5+δ in the temperature range from 298 K up to 1073 K under Po2=0.21 atm has not shown any phase tra...

  16. Solid-state phase equilibria in the Fe-Pt-Pr ternary system at 1173 K

    International Nuclear Information System (INIS)

    Ren Jing; Gu Zhengfei; Cheng Gang; Zhou Huaiying

    2005-01-01

    The solid-state phase equilibria in the Fe-Pt-Pr ternary system at 1173 K (Pr ≤ 70%) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. The 1173 K isothermal section consists of 13 single-phase regions, 22 two-phase regions and 10 three-phase regions. At 1173 K, we have observed that the maximum solid solubility of Pt in α-Fe is below 1.5 at.% and the solid solution region of Pt in γ-Fe is from 2 to 35 at.%; the maximum solid solubility of Fe in Pt is 18 at.%. The maximum solubility of Fe in PrPt 5 , PrPt 3 , PrPt 2 , Pr 3 Pt 4 , PrPt, Pr 3 Pt 2 and Pr 7 Pt 3 is below 1 at.%. The maximum solubility of Pr in α-(Fe, Pt), γ-(Fe, Pt), FePt, FePt 3 and (Pt, Fe) (the solid solution of Fe in Pt) is 6, 2, 4, 4.5 and 1.5 at.%, respectively. In this work, it is found that the phase Pr 3 Pt 4 does not exist in the ternary system. The binary compounds Fe 7 Pr and Fe 2 Pr and any new ternary compounds were not observed

  17. Phase equilibria of the Al-Pr-Zr ternary system at 773 K

    Energy Technology Data Exchange (ETDEWEB)

    She, Jia [Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004 (China); Zhan, Yongzhong, E-mail: zyzmatres@yahoo.com.c [Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004 (China); Li, Chunliu [Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004 (China); Du, Yong; Xu, Honghui; He, Yuehui [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

    2010-07-30

    The phase equilibria of the Al-Pr-Zr ternary system at 773 K have been investigated mainly by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The 14 binary compounds, i.e. AlZr{sub 3}, AlZr{sub 2}, Al{sub 2}Zr{sub 3}, Al{sub 3}Zr{sub 4}, AlZr, Al{sub 3}Zr{sub 2}, Al{sub 2}Zr, Al{sub 3}Zr, {alpha}-Al{sub 11}Pr{sub 3}, Al{sub 3}Pr, Al{sub 2}Pr, {beta}-AlPr, AlPr{sub 2} and {beta}-AlPr{sub 3} were confirmed. No binary compound was found in the Pr-Zr binary system. The result shows that the isothermal section of the Al-Pr-Zr ternary system at 773 K consists of 17 single-phase regions, 31 two-phase regions and 15 three-phase regions. All the intermediate compounds phases in this system have not a remarkable solid solution at 773 K. No ternary compound is found in this work.

  18. Phase equilibria of the Al-Pr-Zr ternary system at 773 K

    International Nuclear Information System (INIS)

    She, Jia; Zhan, Yongzhong; Li, Chunliu; Du, Yong; Xu, Honghui; He, Yuehui

    2010-01-01

    The phase equilibria of the Al-Pr-Zr ternary system at 773 K have been investigated mainly by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The 14 binary compounds, i.e. AlZr 3 , AlZr 2 , Al 2 Zr 3 , Al 3 Zr 4 , AlZr, Al 3 Zr 2 , Al 2 Zr, Al 3 Zr, α-Al 11 Pr 3 , Al 3 Pr, Al 2 Pr, β-AlPr, AlPr 2 and β-AlPr 3 were confirmed. No binary compound was found in the Pr-Zr binary system. The result shows that the isothermal section of the Al-Pr-Zr ternary system at 773 K consists of 17 single-phase regions, 31 two-phase regions and 15 three-phase regions. All the intermediate compounds phases in this system have not a remarkable solid solution at 773 K. No ternary compound is found in this work.

  19. The calculation of phase equilibria of oxide core-concrete systems

    International Nuclear Information System (INIS)

    Ball, R.G.J.; Mignanelli, M.A.; Barry, T.I.; Gisby, J.A.

    1993-01-01

    Thermodynamic models have been developed to describe the phase equilibria of oxide solutions appropriate for the understanding of the chemical interactions between nuclear reactor core debris and concrete. For this purpose, the Gibbs energy of the liquid phase is described by the inclusion of associate species and nonideal interactions between the components and associate species. Assessments of the thermodynamic and phase equilibrium data for the subsystems of the CaO-Al 2 O 3 -SiO 2 -UO 2 -ZrO 2 system have been used to obtain a thermodynamic description of the crystalline and liquid phases in good agreement with published data. The data for the subsystems have then been combined, using well established principles, to predict the phase relationships in the ternary and quaternary sytsems and in the overall quinary system. The results show that he overall system cannot properly be treated as a pseudo-ideal liquid and solid solution, as used in some computer codes which attempt to model the physics and chemistry of core-concrete interactions. The limitations of the current model are discussed. (orig.)

  20. Phase equilibria in the ternary In-Ni-Sn system at 700 °C.

    Science.gov (United States)

    Schmetterer, C; Zemanova, A; Flandorfer, H; Kroupa, A; Ipser, H

    2013-04-01

    The phase equilibria of the ternary system In-Ni-Sn were investigated experimentally at 700 °C using X-ray diffraction (XRD) and scanning electron microscopy (SEM) including electron micro probe analysis (EMPA) and energy dispersive X-ray spectroscopy (EDX). A corresponding isothermal section was established based on these results. This particular temperature was chosen because it allowed obtaining reliable results within reasonable time. The existence of the ternary phase InNi 6 Sn 5 was confirmed whereas the ternary compound In 2 NiSn, reported earlier in literature, was found to be part of a large solid solution field based on binary InNi. The ternary solubility of the binary phases was established, and continuous solid solutions were found between the isostructural phases Ni 3 Sn LT and InNi 3 as well as between Ni 3 Sn 2 HT and InNi 2 . In addition, this isothermal section could be well reproduced by CALPHAD modelling. The resulting calculated isotherm at 700 °C is presented, too, and compared with the experimental results.

  1. The heat-capacity of ilmenite and phase equilibria in the system Fe-T-O

    Science.gov (United States)

    Anovitz, Lawrence M.; Treiman, A.H.; Essene, E.J.; Hemingway, B.S.; Westrum, E.F.; Wall, V.J.; Burriel, R.; Bohlen, S.R.

    1985-01-01

    Low temperature adiabatic calorimetry and high temperature differential scanning calorimetry have been used to measure the heat-capacity of ilmenite (FeTiO3) from 5 to 1000 K. These measurements yield S2980 = 108.9 J/(mol ?? K). Calculations from published experimental data on the reduction of ilmenite yield ??2980(I1) = -1153.9 kJ/(mol ?? K). These new data, combined with available experimental and thermodynamic data for other phases, have been used to calculate phase equilibria in the system Fe-Ti-O. Calculations for the subsystem Ti-O show that extremely low values of f{hook}O2 are necessary to stabilize TiO, the mineral hongquiite reported from the Tao district in China. This mineral may not be TiO, and it should be re-examined for substitution of other elements such as N or C. Consideration of solid-solution models for phases in the system Fe-Ti-O allows derivation of a new thermometer/oxybarometer for assemblages of ferropseudobrookite-pseudobrookitess and hematite-ilmenitess. Preliminary application of this new thermometer/oxybarometer to lunar and terrestrial lavas gives reasonable estimates of oxygen fugacities, but generally yields subsolidus temperatures, suggesting re-equilibration of one or more phases during cooling. ?? 1985.

  2. Studies of Redox Equilibria at Elevated Temperatures I. The Estimation of Equilibrium Constants and Standard Potentials for Aqueous Systems up to 374 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Derek

    1969-07-01

    A method is described for the estimation of equilibrium constants for aqueous systems at temperatures up to 374 deg C from entropy and free energy data for 25 deg C and data on the variation of heat capacity with temperature. Partial molal heat capacities of aqueous ions are estimated on the basis of the principle that, with suitably chosen standard states, the partial molal entropies of ions of a particular class at any given temperature are linearly related to the corresponding entropies at some reference temperature. The method suggested is compared with other methods, based on the Van't Hoff isobar and on an extension of the conventional scale of ionic free energy at 25 deg C, and the general dependence of aqueous equilibria on ionic heat capacity is considered.

  3. Influence of the temperature on the (liquid + liquid) phase equilibria of (water + 1-propanl + linalool or geraniol)

    International Nuclear Information System (INIS)

    Wan, Li; Li, Hengde; Huang, Cheng; Feng, Yuqing; Chu, Guoqiang; Zheng, Yuying; Tan, Wei; Qin, Yanlin; Sun, Dalei; Fang, Yanxiong

    2017-01-01

    Highlights: • Ternary LLEs containing linalool and geraniol are presented. • Distribution ratios of 1-propanol in the mixtures are examined. • Influence of the temperature on the LLE is studied. • The LLE data were correlated using the NRTL and UNIQUAC models. - Abstract: Linalool and geraniol are the primary components of rose oil, palmarosa oil, and citronella oil and many other essential oils, and two important compounds used in the flavour and fragrance, cosmetic or pharmaceutical industries. Phase equilibria (LLE, VLE, solubility, etc.) and related thermodynamic properties of a mixture are essential in the processes design and control of mass transfer process. In this work, experimental (liquid + liquid) equilibria data of the systems (water + 1-propanl + linalool) and (water + 1-propanl + geraniol) are presented. The (liquid + liquid) equilibria of both systems were determined with a tie-line method at T = (283.15, 298.15 and 313.15) K under atmospheric pressure. The well-known Hand, Bachman and Othmer–Tobias equations were used to test the reliability of the experimental values. The influence of the temperature on the (liquid + liquid) phase equilibria of the mixtures, the binodal curves and distribution ratios of 1-propanl are shown and discussed. Moreover, the NRTL and UNIQUAC models were applied to fit the data for both ternary systems. The interaction parameters obtained from both models successfully correlated the equilibrium compositions. Furthermore, the ternary systems could be represented using the binary parameters of the thermodynamic model with a function of temperature.

  4. Survey of the calculation of phase equilibria with the aid of the UNIFAC-method

    Energy Technology Data Exchange (ETDEWEB)

    Gmehling, J.; Rasmussen, P.; Fredenslund, A.

    1981-09-01

    In the design of diffusional separation processes and for many other practical purposes one needs quantitative estimates of phase equilibrium compositions. These compositions can today be predicted with good results using modern, two-parameter models for the excess Gibbs energy. However, since the number of different multicomponent mixtures of interest in chemical technology is very large, it is in practise often not possible to find experimental data in the literature for all the possible binary combinations. In these cases it is necessary to use a predictive approach. Today, group-contribution methods such as ASOG and UNIFAC may be used with confidence to predict liquid phase excess Gibbs energies. In these methods, the mixture is assumed to consist not of molecules but of the functional groups which, when added form the parent molecules. This has the advantage that a large number of mixtures of interest in chemical technology can be described in terms of relatively few parameters characterizing the interactions between the groups. This review article demonstrates the application of the UNIFAC method to various practical problems within phase equilibria. The UNIFAC method applies to mixtures of nonelectrolytes in the temperature range of 275-425 K and at pressures up to 10 bar.

  5. Evaluation of ΔGsub(f) values for unstable compounds: a Fortran program for the calculation of ternary phase equilibria

    International Nuclear Information System (INIS)

    Throop, G.J.; Rogl, P.; Rudy, E.

    1978-01-01

    A Fortran IV program was set up for the calculation of phase equilibria and tieline distributions in ternary systems of the type: transition metal-transition metal-nonmetal (interstitial type of solid solutions). The method offers the possibility of determining the thermodynamic values for unstable compounds through their influence upon ternary phase equilibria. The variation of the free enthalpy of formation of ternary solid solutions is calculated as a function of nonmetal content, thus describing the actual curvature of the phase boundaries. The integral and partial molar free enthalpies of formation of binary nonstoichiometric compounds and of phase solutions are expressed as analytical functions of the nonmetal content within their homogeneity range. The coefficient of these analytical expressions are obtained by the use either of the Wagner-Schottky vacancy model or polynomials second order in composition (parabolic approach). The free energy of formation, ΔGsub(f) has been calculated for the systems Ti-C, Zr-C, and Ta-C. Calculations of the ternary phase equilibria yielded the values for ΔGsub(f) for the unstable compounds Ti 2 C at 1500 0 C and Zr 2 C at 1775 0 C of -22.3 and 22.7 kcal g atom metal respectively. These values were used for the calculation of isothermal sections within the ternary systems Ti-Ta-C (at 1500 0 C) and Zr-Ta-C (at 1775 0 C). The ideal case of ternary phase solutions is extended to regular solutions. (author)

  6. Phase equilibria constraints on the chemical and physical evolution of the campanian ignimbrite

    Science.gov (United States)

    Fowler, S.J.; Spera, F.J.; Bohrson, W.A.; Belkin, H.E.; de Vivo, B.

    2007-01-01

    The Campanian Ignimbrite is a > 200 km3 trachyte-phonolite pyroclastic deposit that erupted at 39.3 ?? 0.1 ka within the Campi Flegrei west of Naples, Italy. Here we test the hypothesis that Campanian Ignimbrite magma was derived by isobaric crystal fractionation of a parental basaltic trachyandesitic melt that reacted and came into local equilibrium with small amounts (5-10 wt%) of crustal rock (skarns and foid-syenites) during crystallization. Comparison of observed crystal and magma compositions with results of phase equilibria assimilation-fractionation simulations (MELTS) is generally very good. Oxygen fugacity was approximately buffered along QFM+1 (where QFM is the quartz-fayalite-magnetite buffer) during isobaric fractionation at 0.15 GPa (???6 km depth). The parental melt, reconstructed from melt inclusion and host clinopyroxene compositions, is found to be basaltic trachyandesite liquid (51.1 wt% SiO2, 9.3 wt% MgO, 3 wt% H2O). A significant feature of phase equilibria simulations is the existence of a pseudo-invariant temperature, ???883??C, at which the fraction of melt remaining in the system decreases abruptly from ???0.5 to point leads to abrupt changes in the composition, properties (density, dissolved water content), and physical state (viscosity, volume fraction fluid) of melt and magma. A dramatic decrease in melt viscosity (from 1700 Pa s to ???200 Pa s), coupled with a change in the volume fraction of water in magma (from ??? 0.1 to 0.8) and a dramatic decrease in melt and magma density acted as a destabilizing eruption trigger. Thermal models suggest a timescale of ??? 200 kyr from the beginning of fractionation until eruption, leading to an apparent rate of evolved magma generation of about 10-3 km3/year. In situ crystallization and crystal settling in density-stratified regions, as well as in convectively mixed, less evolved subjacent magma, operate rapidly enough to match this apparent volumetric rate of evolved magma production

  7. Correlation of phase equilibria for water + hydrocarbon systems at high temperatures and pressures by cubic equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Haruki, Masashi; Yahiro, Yukihito; Higashi, Hidenori; Iwai, Yoshio; Arai, Yasuhiko [Kyushu University, FUkuoka (Japan). Graduate School of Engineering

    1999-08-01

    A modified-Soave-Redlich-Kwong (MSRK) equation of state with an exponent-type mixing rule for the energy parameter and a conventional rule for the size parameter is applied to correlate the phase equilibria for four binary mixtures of water + hydrocarbon (benzene, hexane, decane, and dodecane) systems at high temperatures and pressures. It is noted that good correlation results are obtained by using the mixing rules with interaction parameters between unlike molecules. (author)

  8. Phase extraction equilibria in systems rare earth (3) nitrates-ammonium nitrate-water-trialkylmethylammonium nitrate

    International Nuclear Information System (INIS)

    Pyartman, A.K.; Kopyrin, A.A.; Puzikov, E.A.

    1995-01-01

    The distribution of rare earth metals (3) between aqueous and organic phases in the systems rare earth metal (3) (praseodymium-lutetium (3), yttrium (3)) nitrate-ammonium nitrate-water-trialkylmethylammonium (kerosene diluent nitrate has been studied. It is shown that in organic phase di- and trisolvates of metals (3) with tralkylmethylammonium nitrate are formed. The influence of concentration of rare earth metal (3) nitrate and ammonium nitrate on the values of extraction concentrational constants has been ascertained: they decrease with increase in the ordinal number of lanthanide (3). 11 refs., 4 figs. 1 tab

  9. Phase equilibria of Al3(Ti,V,Zr) intermetallic system

    International Nuclear Information System (INIS)

    Park, S.I.; Han, S.Z.; Choi, S.K.; Lee, H.M.

    1996-01-01

    Trialuminides such as DO 22 -structured Al 3 Ti are promising candidates as potential materials for elevated temperature applications because of their attractive high temperature strength and excellent oxidation resistance along with their low density. However, in the tetragonal structure, slip systems are restricted due to low symmetry and the primary deformation mode is twinning. And, therefore, monolithic trialuminide compounds have been very impractical to be used as structural materials. When transition elements such as Ti, V and Zr which constitute trialuminides are alloyed in aluminum, they have low solubilities and low diffusion coefficients in the Al matrix. If precipitated as trialuminide intermetallics, they maintain a small lattice mismatch with the Al matrix, which reduces the interfacial energy between matrix and precipitates. As a result, these precipitates would have a large coarsening resistance in the matrix. As most of the previous works have been concentrated on the microstructural stability and mechanical properties, thermochemical properties will be treated in this work. In this study, phase equilibria and diagrams of Al 3 (Ti,V,Zr) systems will be experimentally determined and then thermodynamically analyzed with a hope to extend to the Al-Al 3 (Ti,V,Zr) composite system. This approach will then be used as a guide for alloy design of Al-Al 3 (Ti,V,Zr) composite system

  10. Phase equilibria in the Ni–Al–Ga system at 700 °C

    International Nuclear Information System (INIS)

    Belyavina, N.; Markiv, V.; Nakonechna, O.; Lozovyi, F.

    2014-01-01

    Graphical abstract: - Highlights: • We study phase equilibria in ternary Ni–Al–Ga in the whole concentration range. • Ni(Al,Ga), Ni 2 (Al,Ga) 3 , Ni 5 (Al,Ga) 3 extended solid solutions exist in this system. • Isothermal section (700 °C) of the Ni–Al–Ga system has been constructed. • Small additions of Ga increase compressive strength of Ni 3 (Al,Ga) solid solution. - Abstract: Phase relations in the ternary Ni–Al–Ga system at 700 °C have been established by the X-ray powder diffraction methods. In addition to already known Ni 3 (Al,Ga) continuous solid solution, Ni(Al,Ga) continuous solid solution as well as Ni 2 (Al,Ga) 3 and Ni 5 (Al,Ga) 3 extended solid solutions were found to exist in this system. It was shown that the ternary Ni 2 (Al,Ga) 3 and Ni 5 (Al,Ga) 3 compounds do not belong to the continuous solid solutions because of two-phase gaps on the Ni 2 Al 3 –Ni 2 Ga 3 (∼30–50 at.% Ga) and Ni 5 Al 3 –Ni 5 Ga 3 (∼12–25 at.% Ga) isolines at 700 °C. Some crystal structure peculiarities such as atomic ordering–disordering and presence of structural vacancies have been revealed for all solid solutions existing in the Ni–Al–Ga system. It was found that the compressive strength of the Ni 3 (Al,Ga) solid solution increases with small additions of gallium (about 2.5 at.%). The isothermal section (700 °C) of the ternary Ni–Al–Ga system including four extended solid solutions (Ni 3 (Al,Ga), Ni 5 (Al,Ga) 3 , Ni(Al,Ga) and Ni 2 (Al,Ga) 3 ) has been constructed and plotted

  11. Phase equilibria in the BaUO3-BaZrO3-BaMoO3 system

    International Nuclear Information System (INIS)

    Kurosaki, Ken; Yamanaka, Shinsuke; Matsuda, Tetsushi; Uno, Masayoshi; Yamamoto, Kazuya; Namekawa, Takashi

    2002-01-01

    The phase equilibria in the pseudo-ternary BaUO 3 -BaZrO 3 -BaMoO 3 system were studied to understand the thermochemical properties of the perovskite type gray oxide phase in high burnup MOX fuel. Thermodynamic equilibrium calculation for the system was performed by using a Chem Sage program under the various oxygen potentials. Solid solutions existing in the system were treated by an ideal solution model. The present calculation results well agreed with the previous reported post irradiation examination results, showing that BaMoO 3 was scarcely included in the gray oxide phase. (author)

  12. Thermodynamic characteristics of the acid-base equilibria of taurine in aqueous solutions, according to calorimetry data

    Science.gov (United States)

    Gridchin, S. N.; Shekhanov, R. F.; Pyreu, D. F.

    2015-02-01

    Enthalpies of the neutralization and protonation of taurine (HL) are measured by direct calorimetry at 298.15 K and ionic strengths of 0.3, 0.5, and 1.0 (KNO3). The standard thermodynamic characteristics of HL protolytic equilibria are calculated.

  13. Enthalpy of phase transition and prediction of phase Equilibria in systems of glycols and glycol ethers

    OpenAIRE

    Esina, Zoya; Miroshnikov, Aleksandr; Korchuganova, Margarita

    2014-01-01

    The PCEAS model was used to study the liquid-solid and liquid-vapor phase transitions at constant pressure in systems containing glycols and glycol ethers. This method is based on minimizing the excess Gibbs energy over the solvation parameter, which takes into account the processes of association of molecules in various phases. To compute the diagrams, the data on enthalpy and phase transition temperatures of pure components are required, while the information about the interactions in the b...

  14. Thermodynamic analysis and phase equilibria investigation in Pb−Zn−Ag system

    Directory of Open Access Journals (Sweden)

    Mitovski Aleksandra M.

    2010-01-01

    Full Text Available Physico-chemical processes that take place during the refining process in the extractive metallurgy of lead, are connected with ternary Pb−Zn−Ag system, which is necessary to study from the theoretical practical and aspects. Such investigation is important from production point of view, because of the phenomena that occur during desilvering of lead which is one of the important stages during lead refining process. Process of lead desilvering binds to ternary system Pb−Zn−Ag, which was the reason for numerous investigations, both from thermodynamic point of view and in terms of testing and determining the phase diagram, bearing in mind the theoretical, and practical importance of knowledge about the processes which are going in investigated system. The paper presents the results of thermodynamic analysis and investigation of phase equilibria of the Pb−Zn−Ag ternary system using the method of thermodynamic predictions and phase diagrams calculations, respectively, and the experimental results of metalography obtained by optical microscopy. Phase diagram of the vertical section Pb−Zn80Ag20 is presented, obtained by CALPHAD calculation methodology, and using PANDAT thermodynamic software, compared to experimental results obtained by DTA analysis. The results show a pronounced break in solubility, which is characteristic for the whole ternary Pb−Zn−Ag system. Also, it can be noticed that the thermodynamic properties follow the behavior of this system, which is expressed through positive deviation of Raoult’s law, pointing to the lack of lead affinity compared to the other two components in the system. The optical microscopy results of the investigated system show the following: - Sample L1 (weight% Pb = 98: the structure of the observed section shows double eutectic (Pbsol+Zn−Agsol which lies in the base of the primary crystals of lead (Pbsol - Samples L2−L5: the structure consists of a dual eutectic (Pbsol+Zn−Agsol and

  15. Phase Equilibria of the Sn-Ni-Si Ternary System and Interfacial Reactions in Sn-(Cu)/Ni-Si Couples

    Science.gov (United States)

    Fang, Gu; Chen, Chih-chi

    2015-07-01

    Interfacial reactions in Sn/Ni-4.5 wt.%Si and Sn-Cu/Ni-4.5 wt.%Si couples at 250°C, and Sn-Ni-Si ternary phase equilibria at 250°C were investigated in this study. Ni-Si alloys, which are nonmagnetic, can be regarded as a diffusion barrier layer material in flip chip packaging. Solder/Ni-4.5 wt.%Si interfacial reactions are crucial to the reliability of soldered joints. Phase equilibria information is essential for development of solder/Ni-Si materials. No ternary compound is present in the Sn-Ni-Si ternary system at 250°C. Extended solubility of Si in the phases Ni3Sn2 and Ni3Sn is 3.8 and 6.1 at.%, respectively. As more Si dissolves in these phases their lattice constants decrease. No noticeable ternary solubility is observed for the other intermetallics. Interfacial reactions in solder/Ni-4.5 wt.%Si are similar to those for solder/Ni. Si does not alter the reaction phases. No Si solubility in the reaction phases was detected, although rates of growth of the reaction phases were reduced. Because the alloy Ni-4.5 wt.%Si reacts more slowly with solders than pure Ni, the Ni-4.5 wt.%Si alloy could be a potential new diffusion barrier layer material for flip chip packaging.

  16. Effect of Aqueous Phase Recycling in Continuous Hydrothermal Liquefaction

    DEFF Research Database (Denmark)

    Klemmer, Maika; Madsen, René Bjerregaard; Houlberg, Kasper

    2016-01-01

    was observed with a maximum increase in the first recycle experiment. However, the recycling of the aqueous phase also resulted in lower heating values and higher water contents in the oil fraction. Based on these findings, recycling the aqueous phase is a trade-off between improved yields and reduced burn...... qualities of the biocrude. That said, recycling also lowers carbon discharge to the aqueous fraction, which may contribute significantly to reducing the environmental footprint of an industrial HTL plant....

  17. Phase Transformations and Phase Equilibria in the Fe-N System at Temperatures below 573 K

    DEFF Research Database (Denmark)

    Malinov, S.; Böttger, A.J.; Mittemeijer, E.J.

    2001-01-01

    The phase transformations of homogeneous Fe-N alloys of nitrogen contents from 10 to 26 at. pct were investigated by means of X-ray diffraction analysis upon aging in the temperature range from 373 to 473 K. It was found that precipitation of alpha double prime-Fe16N2 below 443 K does not only oc...

  18. Modelling of phase equilibria of glycol ethers mixtures using an association model

    DEFF Research Database (Denmark)

    Garrido, Nuno M.; Folas, Georgios; Kontogeorgis, Georgios

    2008-01-01

    Vapor-liquid and liquid-liquid equilibria of glycol ethers (surfactant) mixtures with hydrocarbons, polar compounds and water are calculated using an association model, the Cubic-Plus-Association Equation of State. Parameters are estimated for several non-ionic surfactants of the polyoxyethylene ...

  19. Thermodynamic modelling of phase equilibria in Al–Ga–P–As system

    Indian Academy of Sciences (India)

    A generalized thermodynamic expression of the liquid Al–Ga–P–As alloys is used in conjunction with the solid solution model in determining the solid–liquid equilibria at 1173 K and 1273 K. The liquid solution model contains thirtyseven parameters. Twentyfour of them pertain to those of the six constituent binaries, twelve ...

  20. Heat capacity and phase equilibria of almandine, Fe3Al2Si3O12

    Science.gov (United States)

    Anovitz, Lawrence M.; Essene, E.J.; Metz, G.W.; Bohlen, S.R.; Westrum, E.F.; Hemingway, B.S.

    1993-01-01

    The heat capacity of a synthetic almandine, Fe3Al2Si3O12, was measured from 6 to 350 K using equilibrium, intermittent-heating quasi-adiabatic calorimetry and from 420 to 1000 K using differential scanning calorimetry. These measurements yield Cp298 = 342.80 ?? 1.4 J/mol ?? K and S298o = 342.60 J/mol ?? K. Mo??ssbauer characterizations show the almandine to contain less than 2 ?? 1% of the total iron as Fe3+. X-ray diffraction studies of this synthetic almandine yield a = 11.521 ?? 0.001 A?? and V298o = 115.11 +- 0.01 cm3/mol, somewhat smaller than previously reported. The low-temperature Cp data indicate a lambda transition at 8.7 K related to an antiferromagnetic-paramagnetic transition with TN = 7.5 K. Modeling of the lattice contribution to the total entropy suggests the presence of entropy in excess of that attributable to the effects of lattice vibrations and the magnetic transition. This probably arises from a low-temperature electronic transition (Schottky contribution). Combination of the Cp data with existing thermodynamic and phase equilibrium data on almandine yields ??Gf,298o = -4938.3 kJ/mol and ??Hf,298o= -5261.3 kJ/mol for almandine when calculated from the elements. The equilibrium almandine = hercynite + fayalite + quartz limits the upper T P for almandine and is metastably located at ca. 570??C at P = 1 bar, with a dP dT of +17 bars/??C. This agrees well with reversed experiments on almandine stability when they are corrected for magnetite and hercynite solid-solutions. In {norm of matrix}O2-T space, almandine oxidizes near QFM by the reactions almandine + O2 = magnetite + sillimanite + quartz and almandine + 02 = hercynite + magnetite + quartz. With suitable correction for reduced activities of solid phases, these equilibria provide useful oxygen barometers for medium- to high-grade metamorphic rocks. ?? 1993.

  1. Prediction of the phase equilibria of methane hydrates using the direct phase coexistence methodology

    Energy Technology Data Exchange (ETDEWEB)

    Michalis, Vasileios K.; Costandy, Joseph; Economou, Ioannis G., E-mail: ioannis.economou@qatar.tamu.edu [Chemical Engineering Program, Texas A and M University at Qatar, P.O. Box 23847, Doha (Qatar); Tsimpanogiannis, Ioannis N.; Stubos, Athanassios K. [Environmental Research Laboratory, National Center for Scientific Research NCSR “Demokritos,” Aghia Paraskevi, Attiki GR-15310 (Greece)

    2015-01-28

    The direct phase coexistence method is used for the determination of the three-phase coexistence line of sI methane hydrates. Molecular dynamics (MD) simulations are carried out in the isothermal–isobaric ensemble in order to determine the coexistence temperature (T{sub 3}) at four different pressures, namely, 40, 100, 400, and 600 bar. Methane bubble formation that results in supersaturation of water with methane is generally avoided. The observed stochasticity of the hydrate growth and dissociation processes, which can be misleading in the determination of T{sub 3}, is treated with long simulations in the range of 1000–4000 ns and a relatively large number of independent runs. Statistical averaging of 25 runs per pressure results in T{sub 3} predictions that are found to deviate systematically by approximately 3.5 K from the experimental values. This is in good agreement with the deviation of 3.15 K between the prediction of TIP4P/Ice water force field used and the experimental melting temperature of ice Ih. The current results offer the most consistent and accurate predictions from MD simulation for the determination of T{sub 3} of methane hydrates. Methane solubility values are also calculated at the predicted equilibrium conditions and are found in good agreement with continuum-scale models.

  2. Formation of aqueous-phase α-hydroxyhydroperoxides (α-HHP: potential atmospheric impacts

    Directory of Open Access Journals (Sweden)

    R. Zhao

    2013-06-01

    Full Text Available The focus of this work is on quantifying the degree of the aqueous-phase formation of α-hydroxyhydroperoxides (α-HHPs via reversible nucleophilic addition of H2O2 to aldehydes. Formation of this class of highly oxygenated organic hydroperoxides represents a poorly characterized aqueous-phase processing pathway that may lead to enhanced SOA formation and aerosol toxicity. Specifically, the equilibrium constants of α-HHP formation have been determined using proton nuclear-magnetic-resonance (1H NMR spectroscopy and proton-transfer-reaction mass spectrometry (PTR-MS. Significant α-HHP formation was observed from formaldehyde, acetaldehyde, propionaldehyde, glycolaldehyde, glyoxylic acid, and methylglyoxal, but not from methacrolein and ketones. Low temperatures enhanced the formation of α-HHPs but slowed their formation rates. High inorganic salt concentrations shifted the equilibria toward the hydrated form of the aldehydes and slightly suppressed α-HHP formation. Using the experimental equilibrium constants, we predict the equilibrium concentration of α-HHPs to be in the μM level in cloud water, but it may also be present in the mM level in aerosol liquid water (ALW, where the concentrations of H2O2 and aldehydes can be high. Formation of α-HHPs in ALW may significantly affect the effective Henry's law constants of H2O2 and aldehydes but may not affect their gas-phase levels. The photochemistry and reactivity of this class of atmospheric species have not been studied.

  3. In situ studies of uranium-plutonium mixed oxides. Influence of composition on phase equilibria and thermodynamic properties

    International Nuclear Information System (INIS)

    Strach, Michal

    2015-01-01

    Due to their physical and chemical properties, mixed uranium-plutonium oxides are considered for fuel in 4. generation nuclear reactors. In this frame, complementary experimental studies are necessary to develop a better understanding of the phenomena that take place during fabrication and operation in the reactor. The focus of this work was to study the U-Pu-O phase diagram in a wide range of compositions and temperatures to ameliorate our knowledge of the phase equilibria in this system. Most of experiments were done using in situ X-ray diffraction at elevated temperatures. The control of the oxygen partial pressure during the treatments made it possible to change the oxygen stoichiometry of the sample, which gave us an opportunity to study rapidly different compositions and the processes involved. The experimental approach was coupled with thermodynamic modeling using the CALPHAD method, to precisely plan the experiments and interpret the obtained results. This approach enabled us to enhance the knowledge of phase equilibria in the U-Pu-O system. (author) [fr

  4. Mars Aqueous Processing System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Aqueous Processing System (MAPS) is a novel technology for recovering oxygen, iron, and other constituents from lunar and Mars soils. The closed-loop...

  5. An energy stable evolution method for simulating two-phase equilibria of multi-component fluids at constant moles, volume and temperature

    KAUST Repository

    Kou, Jisheng; Sun, Shuyu; Wang, Xiuhua

    2016-01-01

    In this paper, we propose an energy-stable evolution method for the calculation of the phase equilibria under given volume, temperature, and moles (VT-flash). An evolution model for describing the dynamics of two-phase fluid system is based on Fick

  6. Phase equilibria and crystalline structure of compounds in the Lu-Al and Lu-Cu-Al systems

    International Nuclear Information System (INIS)

    Kuz'ma, Yu.B.; Stel'makhovich, B.M.; Galamushka, L.I.

    1992-01-01

    Phase equilibria and crystal structure of compounds in Lu-Al and Lu-Cu-Al systems were studied. Existence of Lu 2 Al compound having the structure of the PbCl 2 type is ascertained. Diagram of phase equilibria of Lu-Cu-Al system at 870 K is plotted. Compounds Lu 2 (Cu,Al) 17 (the Th 2 Zn 17 type structure), Lu(Cu,Al) 5 (CaCu 5 type structure), Lu 6 (Cu,Al) 23 (Th 6 Mn 23 type structure) and ∼ LuCuAl 2 have been prepared for the first time. Investigation of component interaction in Lu-Cu-Al system shows that the system is similar to previously studied systems Dy-Cu-Al and Er-Cu-Al. The main difference consists in the absence of LuCuAl 3 compound with rhombic structure of the CeNi 2+x Sb 2-x type in the system investigated

  7. Segregative phase separation in aqueous mixtures of polydisperse biopolymers

    NARCIS (Netherlands)

    Edelman, M.W.

    2003-01-01

    Keywords: biopolymer, gelatine, dextran, PEO, phase separation, polydispersity, molar mass distribution, SEC-MALLS, CSLM The temperature-composition phase diagram of aqueous solutions of gelatine and dextran, which show liquid/liquid phase segregation, were explored at temperatures above the

  8. A New Approach to Modeling Densities and Equilibria of Ice and Gas Hydrate Phases

    Science.gov (United States)

    Zyvoloski, G.; Lucia, A.; Lewis, K. C.

    2011-12-01

    The Gibbs-Helmholtz Constrained (GHC) equation is a new cubic equation of state that was recently derived by Lucia (2010) and Lucia et al. (2011) by constraining the energy parameter in the Soave form of the Redlich-Kwong equation to satisfy the Gibbs-Helmholtz equation. The key attributes of the GHC equation are: 1) It is a multi-scale equation because it uses the internal energy of departure, UD, as a natural bridge between the molecular and bulk phase length scales. 2) It does not require acentric factors, volume translation, regression of parameters to experimental data, binary (kij) interaction parameters, or other forms of empirical correlations. 3) It is a predictive equation of state because it uses a database of values of UD determined from NTP Monte Carlo simulations. 4) It can readily account for differences in molecular size and shape. 5) It has been successfully applied to non-electrolyte mixtures as well as weak and strong aqueous electrolyte mixtures over wide ranges of temperature, pressure and composition to predict liquid density and phase equilibrium with up to four phases. 6) It has been extensively validated with experimental data. 7) The AAD% error between predicted and experimental liquid density is 1% while the AAD% error in phase equilibrium predictions is 2.5%. 8) It has been used successfully within the subsurface flow simulation program FEHM. In this work we describe recent extensions of the multi-scale predictive GHC equation to modeling the phase densities and equilibrium behavior of hexagonal ice and gas hydrates. In particular, we show that radial distribution functions, which can be determined by NTP Monte Carlo simulations, can be used to establish correct standard state fugacities of 1h ice and gas hydrates. From this, it is straightforward to determine both the phase density of ice or gas hydrates as well as any equilibrium involving ice and/or hydrate phases. A number of numerical results for mixtures of N2, O2, CH4, CO2, water

  9. Equation of state modeling of the phase equilibria of asymmetric CO2+n-alkane binary systems using mixing rules cubic with respect to mole fraction

    DEFF Research Database (Denmark)

    Cismondi, Martin; Mollerup, Jørgen M.; Zabaloy, Marcelo S.

    2010-01-01

    for a great diversity of mixtures. Nevertheless, the models for representing phase equilibria and physico-chemical properties of asymmetric systems may require more flexible mixing rules than the classical quadratic van der Waals (vdW) mixing rules or their equivalent (with regard to the number of available...... interaction parameters) in modern equations of state.In particular, the phase equilibria of binary mixtures containing CO2 and heavy n-alkanes have been studied by an important number of authors and using different types of models, achieving only partially accurate results and realizing the difficulties...

  10. Phase equilibria and stability of the B2 phase in the Ni-Mn-Al and Co-Mn-Al systems

    International Nuclear Information System (INIS)

    Kainuma, R.; Ise, M.; Ishikawa, K.; Ohnuma, I.; Ishida, K.

    1998-01-01

    The phase equilibria and ordering reactions in the composition region up to 50 at.% Al have been investigated in the Ni-Mn-Al and Co-Mn-Al systems at temperatures in the interval 850-1200 C mainly by the diffusion couple method. The compositions of the γ (A1: fcc-Ni, -Co, γ-Mn), γ' (L1 2 : Ni 3 Al), β (B2: NiAl, CoAl, NiMn), β-Mn (A13: β-Mn type), δ-Mn (A2: bcc-Mn) and ε (A3: hcp-(Mn, Al)) phases in equilibrium and the critical boundaries of the A2/B2 continuous ordering transition in the bcc phase region have been determined. It is shown that in the Mn-rich portion of the ternary systems both continuous and discontinuous A2 to B2 ordering transitions exist. The A2+B2 two-phase region in the isothermal sections has a lenticular shape and exists over a wide temperature range. The phase equilibria between the γ, γ', β, β-Mn, δ-Mn and ε phases are presented and the stability of the ordered bcc aluminides is discussed. (orig.)

  11. Advanced Aqueous Phase Catalyst Development using Combinatorial Methods, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Combinatorial methods are proposed to develop advanced Aqueous Oxidation Catalysts (AOCs) with the capability to mineralize organic contaminants present in effluents...

  12. Elastic energy and metastable phase equilibria for coherent mixtures in cubic systems

    International Nuclear Information System (INIS)

    Williams, R.O.

    1979-02-01

    Expressions were derived for the elastic energy due to coherency for cubic systems for an isotropic structure and for (100) or (111) habit planes for a lamellar structure. For the metastable equilibria the usual tangent compositions are replaced by compositions that are tangent to the elastic energy curve. For a loss of coherency there is an energy decrease due to the elastic effects and a further decrease associated with compositional changes. Information contained within this treatment permits calculation of the x-ray diffraction effects for such structures

  13. Experimental study of the phase equilibria in the Mg–Zn–Ag ternary system at 300 °C

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian, E-mail: jian.wang@polymtl.ca [Center for Research in Computational Thermochemistry (CRCT), Department of Chemical Engineering, École Polytechnique, Montréal, Québec H3C 3A7 (Canada); Zhang, Yi-Nan [Department of Mechanical Engineering, Concordia University, 1455 De Maisonneuve Blvd. West, Montreal, Quebec H3G 1M8 (Canada); Hudon, Pierre; Jung, In-Ho [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 0C5 (Canada); Medraj, Mamoun [Department of Mechanical Engineering, Concordia University, 1455 De Maisonneuve Blvd. West, Montreal, Quebec H3G 1M8 (Canada); Department of Mechanical and Materials Engineering, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi (United Arab Emirates); Chartrand, Patrice [Center for Research in Computational Thermochemistry (CRCT), Department of Chemical Engineering, École Polytechnique, Montréal, Québec H3C 3A7 (Canada)

    2015-08-05

    Highlights: • The phase equilibria of Mg–Zn–Ag system at 300 °C were determined. • A bcc continuous ternary solid solution forms between MgAg (bcc-B2) and AgZn (bcc-A2) was determined. • The extended solid solubilities of the sub-binary compounds were also determined. - Abstract: The phase equilibria in the Mg–Zn–Ag ternary system at 300 °C were investigated using three diffusion couples and 35 key samples. Scanning electron microscopy (SEM) equipped with energy-dispersive spectroscope (EDS) and X-ray diffraction (XRD) techniques were used for homogeneity ranges and crystal structure determination. Large solid solubility limits, due to substitution among Mg, Zn and Ag atoms in Mg{sub 3}Ag and MgZn{sub 2} phases, were observed in the present work. Solid solubility limits of Ag and Zn in the hcp (Mg) phase were found to be less than 1 at.%. The extended solid solubilities of the Mg{sub 12}Zn{sub 13}, Mg{sub 2}Zn{sub 3}, MgZn{sub 2} (C14), Mg{sub 2}Zn{sub 11}, Ag{sub 5}Zn{sub 8} and hcp (AgZn{sub 3}) sub-binary compounds were also determined in the Mg–Zn–Ag ternary system. In addition, a bcc continuous ternary solid solution forms between MgAg (bcc-B2) and AgZn (bcc-A2) at 300 °C.

  14. Insight into the Am-O Phase Equilibria: A Thermodynamic Study Coupling High-Temperature XRD and CALPHAD Modeling.

    Science.gov (United States)

    Epifano, Enrica; Guéneau, Christine; Belin, Renaud C; Vauchy, Romain; Lebreton, Florent; Richaud, Jean-Christophe; Joly, Alexis; Valot, Christophe; Martin, Philippe M

    2017-07-03

    In the frame of minor actinide transmutation, americium can be diluted in UO 2 and (U, Pu)O 2 fuels burned in fast neutron reactors. The first mandatory step to foresee the influence of Am on the in-reactor behavior of transmutation targets or fuel is to have fundamental knowledge of the Am-O binary system and, in particular, of the AmO 2-x phase. In this study, we coupled HT-XRD (high-temperature X-ray diffraction) experiments with CALPHAD thermodynamic modeling to provide new insights into the structural properties and phase equilibria in the AmO 2-x -AmO 1.61+x -Am 2 O 3 domain. Because of this approach, we were able for the first time to assess the relationships between temperature, lattice parameter, and hypostoichiometry for fcc AmO 2-x . We showed the presence of a hyperstoichiometric existence domain for the bcc AmO 1.61+x phase and the absence of a miscibility gap in the fcc AmO 2-x phase, contrary to previous representations of the phase diagram. Finally, with the new experimental data, a new CALPHAD thermodynamic model of the Am-O system was developed, and an improved version of the phase diagram is presented.

  15. Thermodynamic model for the phase equilibria of gases and brines. Example in the H{sub 2}S-H{sub 2}O-NaCl system

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Reyes, Jose; Gonzalez Partida, Eduardo; Tinoco-Michel, Jorge A [Centro de Geociencias, Universidad Nacional Autonoma de Mexico Campo de Juriquilla, Qro., Mexico, apartado postal 76230 (Mexico); Perez, Renee J; Heidemann, Robert A [Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive, Calgary Alberta, T2N 1N4 (Canada)

    2008-10-01

    We present a thermodynamic model for the phase equilibria of gases and brines, which couples Henry's Law with the Soave-Redlich-Kwong equation of state to reproduce experimental data. In this communication we focus on the H{sub 2}S H{sub 2}O NaCl system.

  16. Performance of predictive models in phase equilibria of complex associating systems: PC-SAFT and CEOS/GE

    Directory of Open Access Journals (Sweden)

    N. Bender

    2013-03-01

    Full Text Available Cubic equations of state combined with excess Gibbs energy predictive models (like UNIFAC and equations of state based on applied statistical mechanics are among the main alternatives for phase equilibria prediction involving polar substances in wide temperature and pressure ranges. In this work, the predictive performances of the PC-SAFT with association contribution and Peng-Robinson (PR combined with UNIFAC (Do through mixing rules are compared. Binary and multi-component systems involving polar and non-polar substances were analyzed. Results were also compared to experimental data available in the literature. Results show a similar predictive performance for PC-SAFT with association and cubic equations combined with UNIFAC (Do through mixing rules. Although PC-SAFT with association requires less parameters, it is more complex and requires more computation time.

  17. Thermodynamic Modeling of Multi-phase Solid–Liquid Equilibria in Industrial-Grade Oils and Fats

    DEFF Research Database (Denmark)

    Hjorth, Jeppe Lindegaard; Miller, Rasmus L.; Woodley, John M.

    2015-01-01

    Compositional thermodynamic phase separation is investigated for industrial-grade vegetable oils with complex compositions. Solid–liquid equilibria have been calculated by utilizing the Margules 2-suffix activity-coefficient model in combination with minimization of the Gibb’s free energy...... of the system. On the basis of quasi-equilibrium solid-fat content (SFC) measurements, a new approach to the estimation of the interaction parameters, needed for the activity-coefficient model, has been developed. The parameters are fitted by matching the SFC of two oils at various degrees of dilution...... and isothermal temperatures. Subsequently, the parameters are successfully validated against three oils, rich in asymmetric and symmetric triacylglycerols (TAG), respectively. The new approach developed is shown to be very flexible, allowing incorporation of additional TAG and polymorphic states. It thereby...

  18. Monosilicide-disilicide-silicon phase equilibria in the nickel-platinum-silicon and nickel-palladium-silicon systems

    Science.gov (United States)

    Loomans, M. E.; Chi, D. Z.; Chua, S. J.

    2004-10-01

    Bulk-phase equilibria in Ni-rich/Si-rich alloys of the Ni-Pt-Si and Ni-Pd-Si systems were investigated. Results suggest that a bulk monosilicide solid solution, containing up to at least 11 at. pct Pt, exists in the Ni-Pt-Si system. Monosilicides containing more than 11 at. pct Pt were not examined. Results from both ternary systems point convincingly to the existence of a NiSi+Si↔NiSi2 eutectoid reaction near 700 °C in the Ni-Si binary system; data from the Ni-Pt-Si system, which yield the more accurate determination of the eutectoid temperature, place it at roughly 710 °C. The Pt and Pd concentrations of monosilicide in equilibrium with disilicide and Si were measured using energy-dispersive spectrometry (EDS) and were found to increase with temperature.

  19. Isothermal sections of phase equilibria diagrams for systems (terbium, dysprosium, holmium)-molybdenum-boron at 1273 K

    International Nuclear Information System (INIS)

    Kuz'ma, Yu.B.; Zakharchuk, N.P.; Maksimova, L.T.

    1988-01-01

    The methods of X-ray analysis are used to study the R-Mo-B (R-Tb, Dy, Ho) systems and isothermal sections of phase equilibria diagrams at 1273 K are plotted. A formation of RMoB 4 (structure of the YCrB 4 type) is confirmed and borides R 3 MoB 7 (structure of the Er 3 CrB 7 type) and ∼ RMo 4 B 8 (of the unknown structure) are obtained for the first time. Borides DyMoB 3 and HoMoB 3 are of the ErMoB 3 structure. Lattice periods of new compounds are indicated. Diffractogrammes of borides Dy 3 MoB 7 and DyMoB 3 are calculated. A peculiarity of components interaction in the systems rare-earth metal-molybdenum-boron is considered

  20. Phase equilibria in the iron oxide-cobalt oxide-phosphorus oxide system

    Science.gov (United States)

    De Guire, Mark R.; Prasanna, T. R. S.; Kalonji, Gretchen; O'Handley, Robert C.

    1987-01-01

    Two novel ternary compounds are noted in the present study of 1000 C solid-state equilibria in the Fe-Co-P-O system's Fe2O3-FePO4-Co3(Po4)2-CoO region: CoFe(PO4)O, which undergoes incongruent melting at 1130 C, and Co3Fe4(PO4)6, whose incongruent melting occurs at 1080 C. The liquidus behavior-related consequences of rapidly solidified cobalt ferrite formation from cobalt ferrite-phosphate melts are discussed with a view to spinel formation. It is suggested that quenching from within the spinel-plus-liquid region may furnish an alternative to quenching a homogeneous melt.

  1. Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2010-08-01

    Full Text Available Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008. This model allows the reliable computation of the liquid-liquid coexistence curve (binodal, corresponding tie-lines, the limit of stability/metastability (spinodal, and further thermodynamic properties of multicomponent systems. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six

  2. α-NiPt(Al) and phase equilibria in the Ni-Al-Pt system at 1150 deg C

    International Nuclear Information System (INIS)

    Hayashi, S.; Ford, S.I.; Young, D.J.; Sordelet, D.J.; Besser, M.F.; Gleeson, B.

    2005-01-01

    The α-NiPt(Al) phase and its associated equilibria in the Ni-Al-Pt system at 1150 deg C were investigated by analyzing equilibrated bulk alloys and the interdiffusion zones of diffusion couples. Phase constitutions, tie-lines and microstructures were determined using a combination of techniques, including high-energy synchrotron X-ray diffraction, scanning electron microscopy and electron probe microanalysis. A large Pt solubility limit was found to exist in the β-NiAl, ∼42 at.%, and in γ'-Ni 3 Al, ∼32 at.%. The α-NiPt(Al) phase was found to have wide Pt solubility range of about 33-60 at.% and to skew along an almost constant Pt/Al ratio of 1.5. The α-NiPt(Al) has an ordered face-centered tetragonal L1 0 crystal structure, with the Al and Pt atoms found to be preferentially located in the corners and prismatic faces, respectively. The temperature dependence of the lattice parameters and unit cell volume of the α phase were also determined

  3. Aqueous-Phase Acetic Acid Ketonization over Monoclinic Zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Qiuxia [Institute for Integrated Catalysis, Pacific Northwest; College; Lopez-Ruiz, Juan A. [Institute for Integrated Catalysis, Pacific Northwest; Cooper, Alan R. [Institute for Integrated Catalysis, Pacific Northwest; Wang, Jian-guo [College; Albrecht, Karl O. [Institute for Integrated Catalysis, Pacific Northwest; Mei, Donghai [Institute for Integrated Catalysis, Pacific Northwest

    2017-12-13

    The effect of aqueous phase on the acetic acid ketonization over monoclinic zirconia has been investigated using first-principles based density functional theory (DFT) calculations. To capture the aqueous phase chemistry over the solid zirconia catalyst surface, the aqueous phase is represented by 111 explicit water molecules with a liquid water density of 0.93 g/cm3 and the monoclinic zirconia is modeled by the most stable surface structure . The dynamic nature of aqueous phase/ interface was studied using ab initio molecular dynamics simulation, indicating that nearly half of the surface Zr sites are occupied by either adsorbed water molecules or hydroxyl groups at 550 K. DFT calculations show that the adsorption process of acetic acid from the liquid water phase to the surface is nearly thermodynamically neutral with a Gibbs free energy of -2.3 kJ/mol although the adsorption strength of acetic acid on the surface in aqueous phase is much stronger than in vapor phase. Therefore it is expected that the adsorption of acetic acid will dramatically affects aqueous phase ketonization reactivity over the monoclinic zirconia catalyst. Using the same ketonization mechanism via the β-keto acid intermediate, we have compared acetic acid ketonization to acetone in both vapor and aqueous phases. Our DFT calculation results show although the rate-determining step of the β-keto acid formation via the C-C coupling is not pronouncedly affected, the presence of liquid water molecules will dramatically affect dehydrogenation and hydrogenation steps via proton transfer mechanism. This work was financially supported by the United States Department of Energy (DOE)’s Bioenergy Technologies Office (BETO) and performed at the Pacific Northwest National Laboratory (PNNL). PNNL is a multi-program national laboratory operated for DOE by Battelle Memorial Institute. Computing time and advanced catalyst characterization use was granted by a user proposal at the William R. Wiley

  4. Phase equilibria and thermodynamics of the Fe–Al–C system: Critical evaluation, experiment and thermodynamic optimization

    International Nuclear Information System (INIS)

    Phan, Anh Thu; Paek, Min-Kyu; Kang, Youn-Bae

    2014-01-01

    In order to provide an efficient tool to design alloy chemistry and processing conditions for high-strength, lightweight steel, an investigation of the Fe–Al–C ternary system was carried out by experimental phase diagram measurement and a CALPHAD thermodynamic analysis. Discrepancies between previously available experimental results and thermodynamic calculations were identified. The Fe–Al sub-binary system was re-optimized in order to obtain an accurate description of the liquid phase, while Gibbs energies of solid phases were mainly taken from a previous thermodynamic modeling. Phase equilibria among face-centered cubic (fcc)/body-centered cubic (bcc)/graphite/κ-carbide/liquid phases in the Fe–Al–C system in the temperature range from 1000 to 1400 °C were obtained by chemical equilibration followed by quenching, and subsequent composition analysis using electron probe microanalysis/inductively coupled plasma spectroscopy. By merging the revised Fe–Al binary description with existing Fe–C and Al–C binary descriptions, a complete thermodynamic description of the Fe–Al–C system was obtained in the present study. The modified quasi-chemical model in the pair approximation was used to model the liquid phase, while solid solutions were modeled using compound energy formalism. A2/B2 order/disorder transition in the bcc phase was taken into account. Compared with previously known experiments/thermodynamic modeling, a better agreement was obtained in the present study, regarding the stable region of fcc and the solidification thermal peak of a ternary alloy near the liquidus temperature. The obtained thermodynamic description also reproduced various types of experimental data in the Fe–Al–C system such as isothermal sections, vertical sections, liquidus projection, etc. The solidification of various steel grades was predicted and discussed

  5. Quantifying geological uncertainty in metamorphic phase equilibria modelling; a Monte Carlo assessment and implications for tectonic interpretations

    Directory of Open Access Journals (Sweden)

    Richard M. Palin

    2016-07-01

    Full Text Available Pseudosection modelling is rapidly becoming an essential part of a petrologist's toolkit and often forms the basis of interpreting the tectonothermal evolution of a rock sample, outcrop, or geological region. Of the several factors that can affect the accuracy and precision of such calculated phase diagrams, “geological” uncertainty related to natural petrographic variation at the hand sample- and/or thin section-scale is rarely considered. Such uncertainty influences the sample's bulk composition, which is the primary control on its equilibrium phase relationships and thus the interpreted pressure–temperature (P–T conditions of formation. Two case study examples—a garnet–cordierite granofels and a garnet–staurolite–kyanite schist—are used to compare the relative importance that geological uncertainty has on bulk compositions determined via (1 X-ray fluorescence (XRF or (2 point counting techniques. We show that only minor mineralogical variation at the thin-section scale propagates through the phase equilibria modelling procedure and affects the absolute P–T conditions at which key assemblages are stable. Absolute displacements of equilibria can approach ±1 kbar for only a moderate degree of modal proportion uncertainty, thus being essentially similar to the magnitudes reported for analytical uncertainties in conventional thermobarometry. Bulk compositions determined from multiple thin sections of a heterogeneous garnet–staurolite–kyanite schist show a wide range in major-element oxides, owing to notable variation in mineral proportions. Pseudosections constructed for individual point count-derived bulks accurately reproduce this variability on a case-by-case basis, though averaged proportions do not correlate with those calculated at equivalent peak P–T conditions for a whole-rock XRF-derived bulk composition. The main discrepancies relate to varying proportions of matrix phases (primarily mica relative to

  6. Thermodynamic calculation of Al-Gd and Al-Gd-Mg phase equilibria checked by key experiments

    International Nuclear Information System (INIS)

    Groebner, J.; Kevorkov, D.; Schmid-Fetzer, R.

    2001-01-01

    The binary Al-Gd and the ternary Al-Gd-Mg systems were calculated using the Calphad method. It is demonstrated that previous interpretation of ternary liquidus temperatures below 700 C must be related to other phase equilibria. The actual ternary liquidus temperatures are much higher, up to some 600 C above the previous interpretation in literature. They are widely governed by the high-melting compounds Al 2 Gd and Al 3 Gd with liquidus surfaces stretching far into the ternary system. A small number of key experiments in this work confirmed the calculated liquidus temperature and the phase relations. The available experimental data in literature fit excellently with the calculation in the binary Al-Gd system. In the ternary Al-Gd-Mg system, which is shown in several sections of the phase diagram, a good agreement can be observed too, considering the necessary reinterpretation of the liquidus temperatures suggested by Rokhlin et al. Ternary solubilities were not found experimentally. The ternary compound Al 4 GdMg (τ) forms in a ternary peritectic reaction at 761 C. (orig.)

  7. High-Temperature Phase Equilibria of Duplex Stainless Steels Assessed with a Novel In-Situ Neutron Scattering Approach

    Science.gov (United States)

    Pettersson, Niklas; Wessman, Sten; Hertzman, Staffan; Studer, Andrew

    2017-04-01

    Duplex stainless steels are designed to solidify with ferrite as the parent phase, with subsequent austenite formation occurring in the solid state, implying that, thermodynamically, a fully ferritic range should exist at high temperatures. However, computational thermodynamic tools appear currently to overestimate the austenite stability of these systems, and contradictory data exist in the literature. In the present work, the high-temperature phase equilibria of four commercial duplex stainless steel grades, denoted 2304, 2101, 2507, and 3207, with varying alloying levels were assessed by measurements of the austenite-to-ferrite transformation at temperatures approaching 1673 K (1400 °C) using a novel in-situ neutron scattering approach. All grades became fully ferritic at some point during progressive heating. Higher austenite dissolution temperatures were measured for the higher alloyed grades, and for 3207, the temperature range for a single-phase ferritic structure approached zero. The influence of temperatures in the region of austenite dissolution was further evaluated by microstructural characterization using electron backscattered diffraction of isothermally heat-treated and quenched samples. The new experimental data are compared to thermodynamic calculations, and the precision of databases is discussed.

  8. Quantitative analysis of aqueous phase composition of model dentin adhesives experiencing phase separation

    Science.gov (United States)

    Ye, Qiang; Park, Jonggu; Parthasarathy, Ranganathan; Pamatmat, Francis; Misra, Anil; Laurence, Jennifer S.; Marangos, Orestes; Spencer, Paulette

    2013-01-01

    There have been reports of the sensitivity of our current dentin adhesives to excess moisture, for example, water-blisters in adhesives placed on over-wet surfaces, and phase separation with concomitant limited infiltration of the critical dimethacrylate component into the demineralized dentin matrix. To determine quantitatively the hydrophobic/hydrophilic components in the aqueous phase when exposed to over-wet environments, model adhesives were mixed with 16, 33, and 50 wt % water to yield well-separated phases. Based upon high-performance liquid chromatography coupled with photodiode array detection, it was found that the amounts of hydrophobic BisGMA and hydrophobic initiators are less than 0.1 wt % in the aqueous phase. The amount of these compounds decreased with an increase in the initial water content. The major components of the aqueous phase were hydroxyethyl methacrylate (HEMA) and water, and the HEMA content ranged from 18.3 to 14.7 wt %. Different BisGMA homologues and the relative content of these homologues in the aqueous phase have been identified; however, the amount of crosslinkable BisGMA was minimal and, thus, could not help in the formation of a crosslinked polymer network in the aqueous phase. Without the protection afforded by a strong crosslinked network, the poorly photoreactive compounds of this aqueous phase could be leached easily. These results suggest that adhesive formulations should be designed to include hydrophilic multimethacrylate monomers and water compatible initiators. PMID:22331596

  9. Fluid phase equilibria during propylene carbonate synthesis from propylene oxide in carbon dioxide medium

    DEFF Research Database (Denmark)

    Gharnati, Loubna; Musko, Nikolai; Jensen, Anker Degn

    2013-01-01

    -cyclic guanidinium bromide on SBA-15 (HEPCGBr/SBA-15) as catalyst in the absence of any co-catalyst. It was found that the yield was strongly dependent on the amount of CO2 added to the system and that the phase behavior strongly changes along the reaction pathway. The Cubic-Plus-Association (CPA) equation of state...... was used to predict the phase behavior during the reaction and the number and composition of coexisting phases in the multicomponent reaction system were determined. In accordance with the experimental data, the maximum conversion was achieved in the transition region between the two- and the one-phase...... region where a CO2-expanded reactant/product phase (larger volume due to the dissolution of carbon dioxide in the liquid phase) is present. Optimal conditions for performing the reaction have been derived which requires consideration not only of the phase behavior of the starting phase but also...

  10. Experimental (solid + liquid) or (liquid + liquid) phase equilibria of (amine + nitrile) binary mixtures

    International Nuclear Information System (INIS)

    Domanska, Urszula; Marciniak, Malgorzata

    2007-01-01

    (Solid + liquid) phase diagrams have been determined for (hexylamine, or octylamine, or 1,3-diaminopropane + acetonitrile) mixtures. Simple eutectic systems have been observed in these mixtures. (Liquid + liquid) phase diagrams have been determined for (octylamine, or decylamine + propanenitrile, or + butanenitrile) mixtures. Mixtures with propanenitrile and butanenitrile show immiscibility in the liquid phase with an upper critical solution temperature, UCST. (Solid + liquid) phase diagrams have been correlated using NRTL, NRTL 1, Wilson and UNIQUAC equations. (Liquid + liquid) phase diagrams have been correlated using NRTL equation

  11. Experimental study on the phase equilibria of the Ag-Ti system

    International Nuclear Information System (INIS)

    Fu Xiaoliang; Li Changrong; Wang Fuming; Li Mei; Zhang Weijing

    2005-01-01

    The Ag-Ti diffusion couples were prepared by small pure silver plates closely packed in pure titanium powder, sealed in quartz tube, and annealed at 750 deg. C, 980 deg. C, 1100 deg. C and 1200 deg. C, respectively. The phase equilibrium relationship and the conjugate phase compositions in the Ag-Ti system were determined by means of the metallographic microscope and the electron probe microanalysis. Partial liquidus and solidus for the two-phase equilibrium, liquid + (βTi), were obtained. The narrow solution range for the intermediate phase (TiAg) was determined

  12. Oxygen potentials and phase equilibria of the quaternary Y-Ba-Cu-O system in the region involving the YBa2Cu3O7-x phase

    International Nuclear Information System (INIS)

    Fitzner, K.; Musbah, O.; Hsieh Kerchang; Zhang Minxian; Chang, Y.A.

    1993-01-01

    The equilibrium oxygen potentials of four-phase equilibria (counting only the condensed phases) in the CuO-Cu 2 O-BaCuO 2 -Y 2 BaCuO 5 (211)-YBa 2 Cu 3 O 7-x (123) phase region were determined using the following solid-oxide electrolyte e.m.f. cell: Pt10Rh, air (psub(O 2 )=0.21 atm) vertical stroke ZrO 2 +Y 2 O 3 vertical stroke mixtures of oxides, Pt. The oxide mixtures whose oxygen potentials were measured were CuO-Cu 2 O-211-123, CuO-Cu 2 O-BaCuO 2 -123, Cu 2 O-BaCuO 2 -211-123 and CuO-BaCuO 2 -211-123. The phase in some of the mixtures were identified by X-ray diffraction. These data were analyzed and are presented using stability diagrams, i.e., oxygen potential as a function of the reciprocal of the temperature. Extrapolation of these data for the four four-phase equilibra to high temperatures yields a metastable five-phase equilibrium, i.e., 123=CuO+Cu 2 O+BaCuO 2 +211, at ∼1243 K (970 ) and log psub(O 2 ) ∼ -1.21 (psub(O 2 )∼0.062 atm). (orig.)

  13. Modelling the phase equilibria of multicomponent mixtures containing CO2, alkanes, water, and/or alcohols using the quadrupolar CPA equation of state

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel; Kontogeorgis, Georgios

    2016-01-01

    In this work, a quadrupolar cubic plus association (qCPA) equation of state is evaluated for its ability to predict the phase equilibria of multicomponent mixtures containing CO2 and alkanes, alcohols, and/or water. A single binary interaction parameter is employed in qCPA for all binary combinat...... CPA yields the best results of all the models for the prediction of dew point pressures....

  14. Phase equilibria of binary, ternary and quaternary systems for polymerization/depolymerization of polycarbonate

    NARCIS (Netherlands)

    Margon, V.; Agarwal, U.S.; Peters, C.J.; Wit, de G.; Bailly, C.M.E.; Kasteren, van J.M.N.; Lemstra, P.J.

    2005-01-01

    Vapor–liquid phase equilibrium is studied for the systems composed of phenol, diphenyl carbonate (DPC), bisphenol A (BPA) and CO2. Bubble point pressures and vapor-phase compositions are measured at various temperatures (343.15–473.15 K) for several compositions of the following systems: two binary

  15. Influence of Adsorption and Capillary Pressure on Phase Equilibria Inside Shale Reservoirs

    DEFF Research Database (Denmark)

    Sandoval, Diego R.; Yan, Wei; Michelsen, Michael L.

    2018-01-01

    is moderate in comparison to the that at low pressure and high temperature. The adsorption effects are stronger for the gas bulk phase region, leading to bigger changes in the gas phase composition and the shift of the dew point curve. PVT simulations of two model reservoir fluid systems show significant...... envelope is different. In general, a much shrunk phase envelope with a shifted critical point is observed. The heavier components are preferentially adsorbed in the whole pressure and temperature range studied here. At high pressure and low temperature, the selectivity towards heavier components...

  16. Peptide-tagged proteins in aqueous two-phase systems

    OpenAIRE

    Nilsson, Anna

    2002-01-01

    This thesis deals with proteins containing peptide tags for improved partitioning in aqueous two-phase systems. Qualitatively the peptide-tagged protein partitioning could be predicted from peptide data, i.e. partitioning trends found for peptides were also found for the peptide-tagged proteins. However, full effect of the tag as expected from peptide partitioning was not found in the tagged protein. When alkyl-ethylene oxide surfactant was included in a two-polymer system, almost full effect...

  17. REVIEWS OF TOPICAL PROBLEMS: Order-disorder transformations and phase equilibria in strongly nonstoichiometric compounds

    Science.gov (United States)

    Gusev, Aleksandr I.

    2000-01-01

    Data on order-disorder phase transformations in strongly nonstoichiometric carbides and nitrides MXy (X=C, N) of Group IV and V transition metals at temperatures below 1300-1400 K are reviewed. The order-parameter functional method as applied to atomic and vacancy ordering in strongly nonstoichiometric MXy compounds and to phase equilibrium calculations for M-X systems is discussed. Phase diagram calculations for the Ti-C, Zr-C, Hf-C, V-C, Nb-C, Ta-C, Ti-N, and Ti-B-C systems (with the inclusion of the ordering of nonstoichiometric carbides and nitrides) and those for pseudobinary carbide M(1)C-M(2)C systems are presented. Heat capacity, electrical resistivity and magnetic susceptibility changes at reversible order-disorder phase transformations in nonstoichiometric carbides are considered.

  18. Phase equilibria and thermodynamic properties of high-alloy tool steels : theoretical and experimental approach

    OpenAIRE

    Bratberg, Johan

    2005-01-01

    The recent development of tool steels and high-speed steels has led to a significant increase in alloy additions, such as Co, Cr, Mo, N, V, and W. Knowledge about the phase relations in these multicomponent alloys, that is, the relative stability between different carbides or the solubility of different elements in the carbides and in the matrix phase, is essential for understanding the behaviour of these alloys in heat treatments. This information is also the basis for improving the properti...

  19. Equilibrium and non-equilibrium extraction separation of rare earth metals in presence of diethylenetriaminepentaacetic acid in aqueous phase

    International Nuclear Information System (INIS)

    Azis, Abdul; Teramoto, Masaaki; Matsuyama, Hideto.

    1995-01-01

    Equilibrium and non-equilibrium extraction separations of rare earth metals were carried out in the presence of chelating agent in the aqueous phase. The separation systems of the rare earth metal mixtures used were Y/Dy, Y/Ho, Y/Er and Y/Tm, and the chelating agent and the extractant were diethylenetriaminepentaacetic acid (DTPA) and bis (2,4,4-trimethylpentyl) phosphinic acid (CYANEXR 272), respectively. For Y/Dy and Y/Ho systems, higher selectivities were obtained in equilibrium separation compared with those in non-equilibrium separation. On the other hand, the selectivities in non-equilibrium separation were higher for Y/Er and Y/Tm systems. In the separation condition suitable to each system, the addition of DTPA to the aqueous phase was found to be very effective for obtaining higher selectivities. The distribution ratios of the rare earth metals and the selectivities in the equilibrium separations obtained experimentally were thoroughly analyzed by considering various equilibria such as the extraction equilibrium and the complex formation equilibrium between rare earth metals and DTPA in the aqueous phase. Moreover, the extraction rates and the selectivities in the non-equilibrium separations were also analyzed by the extraction model considering the dissociation reactions of the rare earth metal-DTPA complexes in the aqueous stagnant layer. Based on these analyses, we presented an index which is useful for selecting the optimum operation mode. Using this index, we can predict that the selectivities under equilibrium conditions are higher than those under non-equilibrium conditions for Y/Dy and Y/Ho systems, while for Y/Er and Y/Tm systems, higher selectivities are obtained under non-equilibrium conditions. The experimental results were in agreement with predictions by this index. Further, the selectivities in various systems including other chelating agents and extractants were discussed based on this index. (J.P.N.)

  20. Attractive evolutionary equilibria

    NARCIS (Netherlands)

    Joosten, Reinoud A.M.G.; Roorda, Berend

    2011-01-01

    We present attractiveness, a refinement criterion for evolutionary equilibria. Equilibria surviving this criterion are robust to small perturbations of the underlying payoff system or the dynamics at hand. Furthermore, certain attractive equilibria are equivalent to others for certain evolutionary

  1. Phase Equilibria in the Bi-In-Sn-Zn System. Thermal Analysis vs. Calculations

    Directory of Open Access Journals (Sweden)

    Dębski A.

    2017-12-01

    Full Text Available With the use of the differential thermal analysis (DTA, studies of the phase transitions were conducted for 90 of alloys from the quaternary Bi-In-Sn-Zn system and for the constant ratio of Bi:In and Bi:Sn. The studies were conducted for the alloys prepared from the purity metals (Bi, In, Sn, Zn = 99.999 mas. % by way of melting in a graphite crucible in a glove-box filled with Ar, in which the impurities level was less than 0.1 ppm. After melting and thorough mixing, the liquid alloys were poured out into a graphite test mold. The phase transition temperature data obtained from the DTA investigations were next confronted with those determined from the calculations based on the binary and ternary optimized thermodynamic parameters available in the literature. It was found that the experimental and the calculated phase transition temperatures were in good agreement.

  2. Vapor-liquid Phase Equilibria for CO2+Tertpentanol Binary System at Elevated Pressures

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; LUO Jian-cheng; YANG Hao; CHEN Kai-xun

    2011-01-01

    Vapor-liquid phase equilibrium data of tertpentanol in carbon dioxide were measured at temperatures of 313.4,323.4,333.5 and 343.5 K and in the pressure range of 4.56-11.44 MPa.The phase equilibium apparatus used in the work was a variable-volume high-pressure cell.The experimental data were reasonably correlated with Peng-Robinson equation of state(PR-EOS) together with van der Waals-2 two-parameter mixing rules.Henry's Law constants and partial molar volumes of CO2 at infinite dilution were estimated with Krichevsky-Kasarnovsky equation,and Henry's Law constants increase with increasing temperature,however,partial molar volumes of CO2 at infinite dilution are negative whose magnitudes decrease with temperature.Partial molar volumes of CO2 and tertpentanol in liquid phase at equilibrium were calculated.

  3. Coal ash fusion temperatures -- New characterization techniques, and associations with phase equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, T.F.; Gupta, R.P.; Gupta, S. [Univ. of Newcastle, New South Wales (Australia). Dept. of Chemical Engineering; Creelman, R.A. [R.A. Creelman and Associates, Epping, New South Wales (Australia); Coin, C. [ACIRL Ipswich, Booval, Queensland (Australia); Lowe, A. [Pacific Power, Sydney, New South Wales (Australia)

    1996-12-31

    The well-documented shortcomings of the standard technique for estimating the fusion temperature of coal ash are its subjective nature and poor accuracy. Alternative measurements based on the shrinkage and electrical conductivity of heating samples are therefore examined with laboratory ash prepared at about 800 C in crucibles, as well as combustion ash sampled from power stations. Sensitive shrinkage measurements indicate temperatures of rapid change which correspond to the formation of liquid phases that can be identified on ternary phase diagrams. The existence and extent of formation of these phases, as quantified by the magnitude of peaks in the test, provide alternative ash fusion temperatures. The peaks from laboratory ashes and corresponding combustion ashes derived from the same coals show clear differences which may be related to the evaporation of potassium during combustion and the reactions of the mineral residues to form combustion ash.

  4. Determination of thermodynamic parameters of tautomerization in gas phase by mass spectrometry and DFT calculations: Keto-enol versus nitrile-ketenimine equilibria.

    Science.gov (United States)

    Giussi, Juan M; Gastaca, Belen; Albesa, Alberto; Cortizo, M Susana; Allegretti, Patricia E

    2011-02-01

    The study of tautomerics equilibria is really important because the reactivity of each compound with tautomeric capacity can be determined from the proportion of each tautomer. In the present work the tautomeric equilibria in some γ,δ-unsaturated β-hydroxynitriles and γ,δ-unsaturated β-ketonitriles were studied. The first family of compounds presents two possible theoretical tautomers, nitrile and ketenimine, while the second one presents four possible theoretical tautomers, keto-nitrile, enol (E and Z)-nitrile and keto-ketenimine. The equilibrium in gas phase was studied by gas chromatography-mass spectrometry (GC-MS). Tautomerization enthalpies were calculated by this methodology, and results were compared with those obtained by density functional theory (DFT) calculations, observing a good agreement between them. Nitrile tautomers were favored within the first family of compounds, while keto-nitrile tautomers were favored in the second family. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Modeling Phase Equilibria for Acid Gas Mixtures using the Cubic-Plus-Association Equation of State. 3. Applications Relevant to Liquid or Supercritical CO2 Transport

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Ali, Shahid; Kontogeorgis, Georgios

    2014-01-01

    density data for both CO2 and CO2–water and for vapor–liquid equilibrium for mixtures of CO2 with various compounds present in transport systems. In all of these cases we consider various possibilities for modeling CO2 (inert, self-associating using two-, three-, and four sites) and the possibility......The CPA (cubic-plus-association) equation of state is applied in this work to a wide range of systems of relevance to CO2 transport. Both phase equilibria and densities over extensive temperature and pressure ranges are considered. More specifically in this study we first evaluate CPA against......” for applying CPA to acid gas mixtures. The overall conclusion is that CPA performs satisfactorily; the model in most cases correlates well binary data and predicts with good accuracy multicomponent vapor–liquid equilibria. Among the various approaches investigated, the best ones are when cross association...

  6. Transport and Phase Equilibria Properties for Steam Flooding of Heavy Oils

    Energy Technology Data Exchange (ETDEWEB)

    Gabitto, Jorge; Barrufet, Maria

    2002-11-20

    The objectives of this research included experimental determination and rigorous modeling and computation of phase equilibrium diagrams, volumetric, and transport properties of hydrocarbon/CO2/water mixtures at pressures and temperatures typical of steam injection processes for thermal recovery of heavy oils.

  7. Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag System

    Czech Academy of Sciences Publication Activity Database

    Živković, D.; Minić, D.; Manasijević, D.; Šesták, Jaroslav; Živković, Ž.

    2011-01-01

    Roč. 47, č. 1 (2011), 23-30 ISSN 1450-5339 Institutional research plan: CEZ:AV0Z10100521 Keywords : Pb-Zn-Ag system * thermal analysis * phase equilibrium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.317, year: 2011

  8. Microstructure and phase equilibria in the Ni-Al-W system

    Czech Academy of Sciences Publication Activity Database

    Popovič, J.; Brož, P.; Buršík, Jiří

    2008-01-01

    Roč. 16, č. 7 (2008), s. 884-888 ISSN 0966-9795 R&D Projects: GA ČR(CZ) GA106/07/1078 Institutional research plan: CEZ:AV0Z20410507 Keywords : nickel aluminides * heat treatment * phase diagram Subject RIV: BJ - Thermodynamics Impact factor: 2.034, year: 2008

  9. Phase equilibria in the ternary In–Ni–Sn system at 700 °C

    Czech Academy of Sciences Publication Activity Database

    Schmetterer, C.; Zemanová, Adéla; Flandorfer, H.; Kroupa, Aleš; Ipser, H.

    2013-01-01

    Roč. 35, APR (2013), s. 90-97 ISSN 0966-9795 R&D Projects: GA MŠk(CZ) OC08053 Institutional support: RVO:68081723 Keywords : intermatallics * miscellaneous * phase diagrams Subject RIV: BJ - Thermodynamics Impact factor: 2.119, year: 2013

  10. Calculation of Liquid Water-Hydrate-Methane Vapor Phase Equilibria from Molecular Simulations

    DEFF Research Database (Denmark)

    Jensen, Lars; Thomsen, Kaj; von Solms, Nicolas

    2010-01-01

    using the TIP4P/ice potential and a united-atom Lennard-Jones potential. respectively. The equilibrium calculation method for this system has three components, (i) thermodynamic integration from a supercritical ideal gas to obtain the fluid-phase chemical potentials. (ii) calculation of the chemical...

  11. The phase equilibria in the Ti-Cu-Y ternary system at 773 K

    Energy Technology Data Exchange (ETDEWEB)

    Hu Zhaohua [Key Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004 (China); Zhan Yongzhong, E-mail: zyzmatres@yahoo.com.c [Key Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004 (China); She Jia; Zhang Guanghua; Peng Dan [Key Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004 (China)

    2009-10-19

    Physical-chemical analysis apparatuses, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA) were employed in constructing the isothermal section of the Ti-Cu-Y system at 773 K. The existences of 10 binary compounds, Ti{sub 2}Cu, TiCu, Ti{sub 3}Cu{sub 4}, Ti{sub 2}Cu{sub 3}, TiCu{sub 4}, Cu{sub 6}Y, Cu{sub 4}Y, Cu{sub 7}Y{sub 2}, Cu{sub 2}Y and CuY were confirmed. The isothermal section consists of 13 single-phase regions, 23 binary phase regions and 11 ternary phase regions. No ternary compound is found in this work. Except the binary compounds YCu{sub 6} and TiCu{sub 4} show homogeneity regions less than 1.5 at.%, none of the other phases in this system reveals a remarkable homogeneity range at 773 K.

  12. Theory of phase equilibria and critical mixing points in binary lipid bilayers

    DEFF Research Database (Denmark)

    Risbo, Jens; Sperotto, Maria Maddalena; Mouritsen, Ole G.

    1995-01-01

    the transition is discussed in terms of the molecular properties of the lipid acyl chains. The results of the numerical model study are expected to have consequences for the interpretation of experimental measurements on lipid bilayer systems in terms of phase diagrams. (C) 1995 American Institute of Physics....

  13. Application of ab initio electronic structure calculations for prediction of phase equilibria in superaustenitic steels

    Czech Academy of Sciences Publication Activity Database

    Vřešťál, J.; Kroupa, Aleš; Šob, Mojmír

    2006-01-01

    Roč. 38, č. 11 (2006), s. 298-302 ISSN 0927-0256 R&D Projects: GA ČR(CZ) GA106/03/1354; GA AV ČR(CZ) IBS2041105 Institutional research plan: CEZ:AV0Z20410507 Keywords : electronic structure * Phase diagrams * Steel Subject RIV: BJ - Thermodynamics Impact factor: 1.104, year: 2006

  14. Synthetic methods in phase equilibria: A new apparatus and error analysis of the method

    DEFF Research Database (Denmark)

    Fonseca, José; von Solms, Nicolas

    2014-01-01

    of the equipment was confirmed through several tests, including measurements along the three phase co-existence line for the system ethane + methanol, the study of the solubility of methane in water, and of carbon dioxide in water. An analysis regarding the application of the synthetic isothermal method...

  15. The system Ta-V-Si: Crystal structure and phase equilibria

    Czech Academy of Sciences Publication Activity Database

    Khan, A.U.; Brož, P.; Niu, H.Y.; Buršík, Jiří; Grytsiv, A.; Chen, X.-Q.; Giester, G.; Rogl, P.

    2012-01-01

    Roč. 187, - (2012), s. 114-123 ISSN 0022-4596 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional research plan: CEZ:AV0Z20410507 Keywords : ternary alloy system * microstructure * phase diagram Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.040, year: 2012

  16. The phase equilibria of multicomponent gas hydrate in methanol/ethylene glycol solution based formation water

    International Nuclear Information System (INIS)

    Xu, Shurui; Fan, Shuanshi; Yao, Haiyuan; Wang, Yanhong; Lang, Xuemei; Lv, Pingping; Fang, Songtian

    2017-01-01

    Highlights: • The equilibrium data in THI solution based formation water is first investigated. • The 0.55 mass fraction concentration of EG 0.55 mass fraction fills the vacancy of this area. • The testing pressure range from 4.22 MPa to 34.72 MPa was rare in published data. - Abstract: In this paper, the three-phase coexistence points are generated for multicomponent gas hydrate in methanol (MeOH) solution for (0.05, 0.10, 0.15, and 0.35) mass fraction and ethylene glycol (EG) solution for (0.05, 0.10, 0.15, 0.35, 0.40 and 0.55) mass fraction. The phase equilibrium curves of different system were obtained by an isochoric pressure-search method on high pressure apparatus. The phase equilibrium regions of multicomponent gas hydrate were measured using the same composition of natural gas distributed in the South China Sea. And the different concentration solutions were prepared based formation water. The experimental data were measured in a wide range temperature from 267.74 to 298.53 K and a wide range pressure from 4.22 MPa to 34.72 MPa. The results showed that the hydrate phase equilibrium curves shifted to the inhibition region in accordance with the increased inhibitor concentration. In addition, the equilibrium temperature would decrease about 2.7 K when the concentration of MeOH increased 0.05 mass fraction. Besides, the suppression temperature was 1.25 K with the 0.05 mass fraction increase of EG concentration in the range of 0.05 mass fraction to 0.15 mass fraction. While in high EG concentration region, the suppression temperature was 3.3 K with the same increase of EG concentration (0.05 mass fraction).

  17. The phase equilibria and thermal stability of the long-period stacking ordered phase in the Mg–Cu–Y system

    International Nuclear Information System (INIS)

    Jiang, Min; Su, Xiulan; Li, Hongxiao; Ren, Yuping; Qin, Gaowu

    2014-01-01

    Highlights: • 14H LPSO structure has been confirmed to be stable in the Mg–Cu–Y system. • Partial isothermal sections of the Mg–Cu–Y system from 300 to 450 °C have been established. • Reaction L + α-Mg ↔ 14H + Mg 2 Cu has been determined in the Mg–Cu–Y system. • The thermal stability of the 14H phase in the Mg–Cu–Y system has been well studied. - Abstract: Phase equilibria in the Mg-rich Mg–Cu–Y system at 300, 400 and 450 °C have been experimentally investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), electron probe micro-analyzer (EPMA) and transmission electron microscope (TEM). The results show that a long-period stacking ordered (LPSO) phase 14H is stable in the Mg–Cu–Y system, which is the only one ternary intermetallic compound that gets a thermodynamic equilibrium with the a-Mg phase. The equilibrium 14H phase has a very limited solid solution range, and can be nearly regarded as a ternary stoichiometric compound with a formulae as Mg 91 Cu 4 Y 5 . The thermal stability of the 14H phase in the Mg–Cu–Y system has been well studied, which shows that the 14H phase disappears varying from 442 °C to 490 °C depending on the alloy composition. The isothermal sections of the Mg-rich Mg–Cu–Y system at 300, 400 and 450 °C have been finally established, and moreover, a quasi-peritectic reaction L + α-Mg ↔ 14H + Mg 2 Cu has been determined occurring at 442 °C with an estimated liquid composition of Mg 77 Cu 18 Y 5

  18. Evolution of the Campanian Ignimbrite Magmatic System I: Constraints on Compositional Zonation and Eruption Probability Imposed By Phase Equilibria

    Science.gov (United States)

    Fowler, S.; Spera, F.; Bohrson, W.; Belkin, H.; Devivo, B.

    2005-12-01

    The eruption and deposition of the ~39.3 ka Campanian Ignimbrite (CI), a large volume (~200 km3 DRE) trachytic to phonolitic ignimbrite, is the dominant event in the history of the Campi Flegrei volcanic field near Naples, Italy. In an effort to comprehend its petrological evolution, we have conducted ~~110 MELTS (Ghiorso, 1997) phase equilibria simulations of the major element evolution of parental CI magma. The goals of this work are to approximate oxygen fugacity (fO2), initial dissolved water content and pressure at which isobaric closed system fractional crystallization of parental melt most accurately captures the observed liquid line of descent and to study the implications of heat extraction from parental CI magma with respect to the origin of compositional zonation and the probability of explosive eruption. Although the CI magma body did not evolve as a perfectly closed system, this assumption allows quantitative insight into magma-host rock mass exchange using trace element and isotopic data (see companion contribution by Bohrson et al.). The parental melt composition was reconstructed using data for melt inclusions trapped within CI clinopyroxene phenocrysts reported by Webster et al. (2003), while allowing for reaction between parental melt and clinopyroxene host. The inferred parental melt is a basaltic trachyandesite. The search space for pressure, (fO2) and initial dissolved H2O was 0.1-0.5 in 0.05 GPa increments, QFM-1 to QFM+3 and 1, 2 and 3 wt. % H2O, respectively. The criteria used to judge the quality of a simulation include correspondence of the MELTS prediction with CI liquid and phenocryst compositions. Results indicate that a good first-order model involves evolution from a basaltic trachyandesite parent by isobaric (~0.15 GPa) crystal fractionation initially containing ~3 wt% dissolved H2O along the QFM+1 buffer. H2O first saturates at 1127°C at 0.15 GPa when the dissolved water content is ~4 wt %. A striking result is the

  19. Phase equilibria of binary mixtures by molecular simulation and cubic equations of state

    Directory of Open Access Journals (Sweden)

    Cabral V.F.

    2001-01-01

    Full Text Available Molecular simulation data were used to study the performance of equations of state (EoS and combining rules usually employed in thermodynamic property calculations. The Monte Carlo method and the Gibbs ensemble technique were used for determining composition and densities of vapor and liquid phases in equilibrium for binary mixtures of Lennard-Jones fluids. Simulation results are compared to data in the literature and to those calculated by the t-PR-LJ EoS. The use of adequate combining rules has been shown to be very important for the satisfactory representation of molecular simulation data.

  20. Phase Equilibria and Ionic Solvation in the Lithium Tetrafluoroborate-Dimethylsulfoxide System

    Science.gov (United States)

    Gafurov, M. M.; Kirillov, S. A.; Gorobets, M. I.; Rabadanov, K. Sh.; Ataev, M. B.; Tretyakov, D. O.; Aydemirov, K. M.

    2015-01-01

    The phase diagram and electrical conductivity isotherms for the lithium tetrafluoroborate (LiBF4)-dimethylsulfoxide (DMSO) system and Raman spectra of DMSO and the LiBF4-DMSO solution were studied. Spectroscopic signatures of a H-bond between DMSO and BF4 - ions were found. The bonds of Li+ ions to the solvent were stronger than the bonds in DMSO dimers because formation of the solvate destroyed dimeric DMSO molecules. The τω values for DMSO molecules in the Li+-ion solvate shell of the LiBF4-DMSO system were similar to those for associated solvent molecules.

  1. Phase equilibria in the system Nd(PO3)3 - KPO3

    International Nuclear Information System (INIS)

    Znamierowska, T.; Mizer, D.

    2002-01-01

    The system Nd(PO 3 ) 3 - KPO 3 has been investigated by differential thermal analysis (during heating), thermogravimetric analysis, mass spectrometry, Raman spectroscopy and X-ray powder diffraction and its phase diagram was proposed. It was discovered that initial metaphosphates react at a 1:1 molar ratio forming intermediate compound KNd(PO 3 ) 4 . It was found that it melts incongruently at 854 o C giving Nd(po)3) 3 and a liquid rich in KPO 3 . Phosphate KNd(PO 3 ) 4 is stable down to room temperature and does not show any polymorphic transitions. (author)

  2. Calculation of phase equilibria in the Na2SO4-K2SO4-Cs2SO4-H2O system at 25 deg C

    International Nuclear Information System (INIS)

    Filippov, V.K.; Kalinkin, A.M.; Vasin, S.K.

    1990-01-01

    Calculation results of solubility diagram and water activity in saturated solutions of Na 2 SO 4 -K 2 SO 4 -Cs 2 SO 4 -H 2 O system at 25 deg C are presented. It is shown that for the calculation of quaternary systems one can use the Pitzer equations. Solubility diagram for the system studied is plotted and data on composition and water activity of solutions saturated by two or three solid phases are given. Classification of nonvariant equilibria from the viewpoint of isomorphism of solubility and fusibility diagrams permits to depict the direction of phase processes during isothermal evaporation of water

  3. Phase equilibria in the system As2-O5 - SrO

    International Nuclear Information System (INIS)

    Kasenov, B.K.; Ashlyaeva, I.V.

    1993-01-01

    T-x phase state diagram of As 2 O 5 -SrO system was investigated by the methods of physicochemical analysis. It was established that incongruently melting Sr(AsO 3 ) 2 (t mel 900 deg C), Sr 2 As 2 O 4 (t mel = 1140 deg C), Sr 4 As 2 O 9 (t mel = 1390 deg C) and congruently melting at 1635 deg C Sr 3 (AsO 4 ) 2 formed in the system. Eutectic points were revealed in the system: As 2 O 5 -Sr(AsO 3 ) 2 (15.0 mol % SrO, 700 deg C) and Sr 3 (AsO 4 ) 2 -Sr 4 As 2 O 9 (78 mol % SrO, 1370 deg C)

  4. Phase equilibria in the system Li2O - MoO3 - Sc2O3

    International Nuclear Information System (INIS)

    Safonov, V.V.; Chaban, N.G.; Porotnikov, N.V.

    1984-01-01

    Using the methods of DTA and X-ray phase analysis, interaction of components in the system Li 2 O-MoO 3 -Sc 2 O 3 in concentration range, adjacent to the vertex of MoO 3 , has been studied. Projection of the Li 2 MoO 4 -MoO 3 -Sc 2 (MoO 4 ) 3 system liquidus on concentrational triangle of the compositions Li 2 O-MoO 3 -Sc 2 O 3 , which consists of the fields of primary separation of Li 2 MoO 4 , Li 2 Mo 5 O 17 , Li 2 Mo 4 O 13 , MoO 3 , Sc 2 (MoO 4 ) 3 , Li 3 Sc(MoO 4 ) 3 and LiSc(MoO 4 ) 2 , is built

  5. Phase equilibria for mixtures containing nonionic surfactant systems: Modeling and experiments

    International Nuclear Information System (INIS)

    Shin, Moon Sam; Kim, Hwayong

    2008-01-01

    Surfactants are important materials with numerous applications in the cosmetic, pharmaceutical, and food industries due to inter-associating and intra-associating bond. We present a lattice fluid equation-of-state that combines the quasi-chemical nonrandom lattice fluid model with Veytsman statistics for (intra + inter) molecular association to calculate phase behavior for mixtures containing nonionic surfactants. We also measured binary (vapor + liquid) equilibrium data for {2-butoxyethanol (C 4 E 1 ) + n-hexane} and {2-butoxyethanol (C 4 E 1 ) + n-heptane} systems at temperatures ranging from (303.15 to 323.15) K. A static apparatus was used in this study. The presented equation-of-state correlated well with the measured and published data for mixtures containing nonionic surfactant systems

  6. Thermal analysis, phase equilibria, and superconducting properties in magnesium boride and carbon doped magnesium boride

    Science.gov (United States)

    Bohnenstiehl, Scot David

    In this work, the low temperature synthesis of MgB2 from Mg/B and MgH2/B powder mixtures was studied using Differential Scanning Calorimetry (DSC). For the Mg/B powder mixture, two exothermic reaction events were observed and the first reaction event was initiated by the decomposition of Mg(OH)2 on the surface of the magnesium powder. For the MgH 2/B powder mixture, there was an endothermic event at ˜375 °C (the decomposition of MgH2 into H2 and Mg) and an exothermic event ˜600 °C (the reaction of Mg and B). The Kissinger analysis method was used to estimate the apparent activation energy of the Mg and B reaction using DSC data with different furnace ramp rates. The limitations of MgB2 low temperature synthesis led to the development of a high pressure induction furnace that was constructed using a pressure vessel and an induction heating power supply. The purpose was to not only synthesize more homogeneous MgB2 samples, but also to determine whether MgB2 melts congruently or incongruently. A custom implementation of the Smith Thermal Analysis method was developed and tested on aluminum and AlB2, the closest analogue to MgB2. Measurements on MgB2 powder and a high purity Mg/B elemental mixture confirmed that MgB2 melts incongruently and decomposes into a liquid and MgB4 at ˜1445 °C at 10 MPa via peritectic decomposition. Another measurement using a Mg/B elemental mixture with impure boron suggested that ˜0.7 wt% carbon impurity in the boron raised the incongruent melting temperature to ˜1490-1500 °C. Lastly, the solubility limit for carbon in MgB2 was studied by making samples from B4C and Mg at 1530 °C, 1600 °C and 1700 °C in the high pressure furnace. All three samples had three phases: Mg, MgB2C2, and carbon doped MgB2. The MgB 2C2 and carbon doped MgB2 grain size increased with temperature and the 1700 °C sample had needle-like grains for both phases. The presence of the ternary phase, MgB2C2, suggested that the maximum doping limit for carbon in

  7. Phase transitions on (liquid + liquid) equilibria for (water + 1-methylnaphthalene + light aromatic hydrocarbon) ternary systems at T = (563, 573, and 583) K

    International Nuclear Information System (INIS)

    Togo, Masaki; Inamori, Yoshiki; Shimoyama, Yusuke

    2012-01-01

    Highlights: ► Mixtures of (water + 1-methylnaphthalene + light aromatic hydrocarbon) are focused. ► Phase transition pressures on (liquid + liquid) equilibria were measured. ► Effects of aromatic hydrocarbons on phase transition pressure are investigated. ► Phase transition pressures are discussed using dielectric constants of hydrocarbons. - Abstract: Phase transitions for (water + 1-methylnaphthalene + light aromatic hydrocarbon) ternary systems are observed at their (liquid + liquid) equilibria at T = (563, 573, and 583) K and (8.6 to 25.0) MPa. The phase transition pressures at T = (563, 573, and 583) K were measured for the five species of light aromatic hydrocarbons, o-, m-, p-xylenes, ethylbenzene, and mesitylene. The measurements of the phase transition pressures were carried out by changing the feed mole fraction of water and 1-methylnaphthalene in water free, respectively. Effects of the feed mole fraction of water on the phase transition pressures are very small. Increasing the feed mole fraction of 1-methylnaphthalene results in decreasing the phase transition pressures at constant temperature. The slopes depending on the feed mole fraction for 1-methylnaphthalene at the phase transition pressures are decreased with increasing temperature for (water + 1-methylnaphthalene + p-xylene), (water + 1-methylnaphthalene + o-xylene), and (water + 1-methylnaphthalene + mesitylene) systems. For xylene isomers, the highest and lowest of the phase transition pressures are obtained in the case of p- and o-xylenes, respectively. The phase transition pressures for ethylbenzene are lower than those in the case of p-xylene. The similar phase transition pressures are given for p-xylene and mesitylene.

  8. Phase Equilibria of a S- and C-Poor Lunar Core

    Science.gov (United States)

    Righter, K.; Pando, K.; Go, B. M.; Danielson, L. R.; Habermann, M.

    2016-01-01

    The composition of the lunar core can have a large impact on its thermal evolution, possible early dynamo creation, and physical state. Geochemical measurements have placed better constraints on the S and C content of the lunar mantle. In this study we have carried out phase equilibrium studies of geochemically plausible S- and C-poor lunar core compositions in the Fe-Ni-S-C system, and apply them to the early history of the Moon. We chose two bulk core compositions, with differing S and C content based on geochemical analyses of S and C trapped melts in Apollo samples, and on the partitioning of S and C between metal and silicate. This approach allowed calculation of core S and C contents - 90% Fe, 9% Ni, 0.5% C, and 0.375% S by weight; a second composition contained 1% each of S and C. Experiments were carried out from 1473K to 1973K and 1 GPa to 5 GPa, in piston cylinder and multi- anvil apparatuses. Combination of the thermal model of with our results, shows that a solid inner core (and therefore initiation of a dynamo) may have been possible in the earliest history of the Moon (approximately 4.2 Ga ago), in agreement with. Thus a volatile poor lunar core may explain the thermal and magnetic history of the Moon.

  9. Phase equilibria, leaching characteristics and ceramic processing of SYNROC D formulations for US defense wastes

    International Nuclear Information System (INIS)

    Newkirk, H.; Ryerson, F.; Coles, D.; Hoenig, C.; Rozsa, R.; Rossington, C.; Bazan, F.; Tewhey, J.

    1980-01-01

    The assemblage of coexisting phases in SYNROC D is perovskite, zirconolite, nepheline and spinel. Cesium from the supernate is to be immobilized in hollandite. In the current processing scheme, presynthesized granules of hollandite are added to calcined SYNROC D powders prior to hot procesing or sintering. The disposition of inert and radwaste components of Savannah River Plant (SRP) wastes in SYNROC D formulations has been determined by means of optical microscopy, XRD, XRF, SEM, STEM, electron microprobe analysis and autoradiography. A summary of results is presented. Leaching studies of SYNROC D have been done by means of static, high temperature experiments and continuous-flow experiments. The data reported are from high-temperature experiments (distilled water, powdered sample, 150 0 C, one day). The elements reported are the only ones observed in the leachate. Analysis was done by means of XRF. The flowsheet which depicts the current experimental methods that are being employed at LLNL to produce SYNROC D samples containing presynthesized Cs-bearing hollandite is presented. The starting material for SYNROC D (high Fe, high Al and composite compositions) is simulated sludge obtained in 55 gallon quantities from Southwestern Chemical Corporation. Hot pressing temperatures for SYNROC D are 1000 to 1150 0 C. Hot pressing temperatures for hollandite are 1200 to 1400 0 C

  10. Thermodynamic characteristics of the acid-base equilibria of ethylenediamine- N, N'-diglutaric acid in aqueous solutions using calorimetric data

    Science.gov (United States)

    Gridchin, S. N.; Nikol'skii, V. M.

    2017-10-01

    The enthalpies of reaction of betaine group neutralization of ethylenediamine- N, N'-diglutaric acid (H4L) at 298.15 K and at different values of ionic strength of 0.1, 0.5, 1.0 (KNO3) is measured by direct calorimetry. The standard thermodynamic characteristics of the protolytic equilibria of H4L are calculated.

  11. Phase equilibria, crystal chemistry, electronic structure and physical properties of Ag-Ba-Ge clathrates

    Energy Technology Data Exchange (ETDEWEB)

    Zeiringer, I.; Chen Mingxing [Institute of Physical Chemistry, University of Vienna, Waehringerstr. 42, 1090 Wien (Austria); Bednar, I.; Royanian, E.; Bauer, E. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Wien (Austria); Podloucky, R.; Grytsiv, A. [Institute of Physical Chemistry, University of Vienna, Waehringerstr. 42, 1090 Wien (Austria); Rogl, P., E-mail: peter.franz.rogl@univie.ac.at [Institute of Physical Chemistry, University of Vienna, Waehringerstr. 42, 1090 Wien (Austria); Effenberger, H. [Institute of Mineralogy and Crystallography, University of Vienna, A-1090 Wien (Austria)

    2011-04-15

    In the Ag-Ba-Ge system the clathrate type-{Iota} solid solution, Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y}, extends at 800 deg. C from binary Ba{sub 8}Ge{sub 43{open_square}3} ({open_square} is a vacancy) to Ba{sub 8}Ag{sub 5.3}Ge{sub 40.7}. For the clathrate phase (1 {<=} x {<=} 5.3) the cubic space group Pm3-bar n was established by X-ray powder diffraction and confirmed by X-ray single-crystal analyses of the samples Ba{sub 8}Ag{sub 2.3}Ge{sub 41.9{open_square}1.8} and Ba{sub 8}Ag{sub 4.4}Ge{sub 41.3{open_square}0.3}. Increasing the concentration of Ag causes the lattice parameters of the solid solution to increase linearly from a value of a = 1.0656 (x = 0, y = 3) to a = 1.0842 (x = 4.8, y = 0) nm. Site preference determination using X-ray refinement reveals that Ag atoms preferentially occupy the 6d site randomly mixed with Ge and vacancies, which become filled in the compound Ba{sub 8}Ag{sub 4.8}Ge{sub 41.2} when the Ag content increases. At 600 {sup o}C the phase region of the clathrate solution Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y} becomes separated from the Ba-Ge boundary and extends from 6.6 to 9.8 at.% Ag. The compound Ba{sub 6}Ge{sub 25} (clathrate type-{Iota}X) dissolves at 800 {sup o}C a maximum of 1.5 at.% Ag. The homogeneity regions of the two ternary compounds BaAg{sub 2-x}Ge{sub 2+x} (ThCr{sub 2}Si{sub 2}-type, 0.2 {<=} x {<=} 0.7) and Ba(Ag{sub 1-x}Ge{sub x}){sub 2} (AlB{sub 2}-type, 0.65 {<=} x {<=} 0.75) were established at 800 deg. C. Studies of transport properties for the series of Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y} compounds evidenced that electrons are the predominant charge carriers with the Fermi energy close to a gap. Its position can be fine-tuned by the substitution of Ge by Ag atoms and by mechanical processing of the starting material, Ba{sub 8}Ge{sub 43}. The proximity of the electronic structure at Fermi energy of Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y} to a gap is also corroborated by density

  12. Phase equilibria and homogeneity range of the high temperature superconducting compound (Bi,Pb)2+xSr2Ca2Cu3O10+δ

    International Nuclear Information System (INIS)

    Kaesche, S.

    1995-01-01

    For the superconducting cuprates (Bi,Pb) 2+x Sr 2 Ca 2 Cu 3 O 10+y phase equilibria, the homogeneity region, and the phase formation has been studied in the temperture range 800 to 890 C. Sintered samples were prepared by a solid state reaction starting from Bi 2 O 3 , PbO, CuO and carbonates CaCO 3 and SrCO 3 in a three-stage calcination process. For the phase identification polarization microscopy, X-ray diffraction and susceptibility measurements have been applied. Multi-phase regions were determined in the cross section of the quasi-ternary system (Bi,Pb) 2 O 3 -SrO-CaO-CuO with constant Bi/(Bi+Pb) ratio 0.84 taking into account the 2223-phase. The homogeneity region was determined as function of Sr, Ca, Bi and Pb concentration. Its maximum size was found at 850 C

  13. Hydrogen Generation from Sugars via Aqueous-Phase Reforming

    International Nuclear Information System (INIS)

    Randy D Cortright

    2006-01-01

    Virent Energy Systems, Inc. is commercializing the Aqueous Phase Reforming (APR) process that allows the generation of hydrogen-rich gas streams from biomass-derived compounds such as glycerol, sugars, and sugar alcohols. The APR process is a unique method that generates hydrogen from aqueous solutions of these oxygenated compounds in a single step reactor process compared to the three or more reaction steps required for hydrogen generation via conventional processes that utilize non-renewable fossil fuels. The key breakthrough of the APR process is that the reforming of these aqueous solutions is done in the liquid phase. The patented APR process occurs at temperatures (150 C to 270 C) where the water-gas shift reaction is favorable, making it possible to generate hydrogen with low amounts of CO in a single chemical reactor. Furthermore, the APR process occurs at pressures (typically 15 to 50 bar) where the hydrogen-rich effluent can be effectively purified using either membrane technology or pressure swing adsorption technology. The utilization of biomass-based compounds allows the APR process to be a carbon neutral method to generate hydrogen. In the near term, the feed-stock of interest is waste glycerol that is being generated in large quantities as a byproduct in the production of bio-diesel. Virent has developed the APR system for on-demand generation of hydrogen-rich fuel gas from either glycerol or sorbitol (the sugar alcohol formed by hydrogenation of glucose) to fuel a stationary internal combustion engine driven generator (10 kW). Under a USDOE funded project, Virent is currently developing the APR process to generate high yields of hydrogen from corn-derived glucose. This project objective is to achieve the DOE 2010 cost target for distributed production from renewable liquid fuels of 3.60 dollars/gge (gasoline gallon equivalent) delivered. (authors)

  14. Experimental Phase Equilibria Studies of the Pb-Fe-O System in Air, in Equilibrium with Metallic Lead and at Intermediate Oxygen Potentials

    Science.gov (United States)

    Shevchenko, M.; Jak, E.

    2017-12-01

    The phase equilibria information on the Pb-Fe-O system is of practical importance for the improvement of the existing thermodynamic database of lead-containing slag systems (Pb-Zn-Fe-Cu-Si-Ca-Al-Mg-O). Phase equilibria of the Pb-Fe-O system have been investigated: (a) in air at temperatures between 1053 K and 1373 K (780 °C and 1100 °C); (b) in equilibrium with metallic lead at temperatures between 1053 K and 1373 K (780 °C and 1100 °C); and (c) at intermediate oxidation conditions for the liquid slag in equilibrium with two solids (spinel + magnetoplumbite), at temperatures between 1093 K and 1373 K (820 °C and 1100 °C). The high-temperature equilibration/quenching/electron probe X-ray microanalysis technique has been used to accurately determine the compositions of the phases in equilibrium in the system. The Pb and Fe concentrations in the phases were determined directly; preliminary thermodynamic modeling with FactSage was used to estimate the ferrous-to-ferric ratios and to present the results in the ternary diagram.

  15. Phase equilibria in the MgMoO4-Ln2(MoO4)3 (Ln=La,Gd) systems

    International Nuclear Information System (INIS)

    Fedorov, N.F.; Ipatov, V.V.; Kvyatkovskij, O.V.

    1980-01-01

    Phase equilibria in the MgMoO 4 -Ln 2 (MoO 4 ) 3 systems (Ln=La, Gd) have been studied by static and dynamic methods of the physico-chemical analysis, using differential thermal, visual-polythermal, crystal-optical, X-ray phase, and infrared spectroscopic methods, and their phase diagrams have been constructed. Phase equilibria in the systems studied are characterized by limited solubility of components in the liquid state, formation of solid solutions on the base of α- and β-forms of Gd 2 (MoO 4 ) 3 . Eutectics in the MgMoO 4 -Ln 2 (MoO 4 ) 3 (Ln=La, Gd) systems corresponds to the composition of 71 mode % La 2 (MoO 4 ) 3 -29 mole % MgMoO 4 , tsub(melt)--935+-5 deg C and 57 mole % Gd 2 (MoO 4 ) 3 -43 mole % MgMoO 4 , tsub(melt)=1020+-5 deg C. The region of glass formation has been established [ru

  16. Glycine phases formed from frozen aqueous solutions: Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Surovtsev, N. V. [Institute of Automation and Electrometry, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Adichtchev, S. V.; Malinovsky, V. K. [Institute of Automation and Electrometry, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Ogienko, A. G.; Manakov, A. Yu. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Drebushchak, V. A. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Ancharov, A. I.; Boldyreva, E. V. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Institute of Solid Chemistry and Mechanochemistry, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Yunoshev, A. S. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Lavrentiev Institute of Hydrodynamics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation)

    2012-08-14

    Glycine phases formed when aqueous solutions were frozen and subsequently heated under different conditions were studied by Raman scattering, x-ray diffraction, and differential scanning calorimetry (DSC) techniques. Crystallization of ice I{sub h} was observed in all the cases. On cooling at the rates of 0.5 K/min and 5 K/min, glassy glycine was formed as an intermediate phase which lived about 1 min or less only, and then transformed into {beta}-polymorph of glycine. Quench cooling of glycine solutions (15% w/w) in liquid nitrogen resulted in the formation of a mixture of crystalline water ice I{sub h} and a glassy glycine, which could be preserved at cryogenic temperatures (80 K) for an indefinitely long time. This mixture remained also quite stable for some time after heating above the cryogenic temperature. Subsequent heating under various conditions resulted in the transformation of the glycine glass into an unknown crystalline phase (glycine 'X-phase') at 209-216 K, which at 218-226 K transformed into {beta}-polymorph of glycine. The 'X-phase' was characterized by Raman spectroscopy; it could be obtained in noticeable amounts using a special preparation technique and tentatively characterized by x-ray powder diffraction (P2, a= 6.648 A, b= 25.867 A, c= 5.610 A, {beta}= 113.12 Masculine-Ordinal-Indicator ); the formation of 'X-phase' from the glycine glassy phase and its transformation into {beta}-polymorph were followed by DSC. Raman scattering technique with its power for unambiguous identification of the crystalline and glassy polymorphs without limitation on the crystallite size helped us to follow the phase transformations during quenching, heating, and annealing. The experimental findings are considered in relation to the problem of control of glycine polymorphism on crystallization.

  17. Glycine phases formed from frozen aqueous solutions: Revisited

    Science.gov (United States)

    Surovtsev, N. V.; Adichtchev, S. V.; Malinovsky, V. K.; Ogienko, A. G.; Drebushchak, V. A.; Manakov, A. Yu.; Ancharov, A. I.; Yunoshev, A. S.; Boldyreva, E. V.

    2012-08-01

    Glycine phases formed when aqueous solutions were frozen and subsequently heated under different conditions were studied by Raman scattering, x-ray diffraction, and differential scanning calorimetry (DSC) techniques. Crystallization of ice Ih was observed in all the cases. On cooling at the rates of 0.5 K/min and 5 K/min, glassy glycine was formed as an intermediate phase which lived about 1 min or less only, and then transformed into β-polymorph of glycine. Quench cooling of glycine solutions (15% w/w) in liquid nitrogen resulted in the formation of a mixture of crystalline water ice Ih and a glassy glycine, which could be preserved at cryogenic temperatures (80 K) for an indefinitely long time. This mixture remained also quite stable for some time after heating above the cryogenic temperature. Subsequent heating under various conditions resulted in the transformation of the glycine glass into an unknown crystalline phase (glycine "X-phase") at 209-216 K, which at 218-226 K transformed into β-polymorph of glycine. The "X-phase" was characterized by Raman spectroscopy; it could be obtained in noticeable amounts using a special preparation technique and tentatively characterized by x-ray powder diffraction (P2, a = 6.648 Å, b = 25.867 Å, c = 5.610 Å, β = 113.12°); the formation of "X-phase" from the glycine glassy phase and its transformation into β-polymorph were followed by DSC. Raman scattering technique with its power for unambiguous identification of the crystalline and glassy polymorphs without limitation on the crystallite size helped us to follow the phase transformations during quenching, heating, and annealing. The experimental findings are considered in relation to the problem of control of glycine polymorphism on crystallization.

  18. Random-lattice models and simulation algorithms for the phase equilibria in two-dimensional condensed systems of particles with coupled internal and translational degrees of freedom

    DEFF Research Database (Denmark)

    Nielsen, Morten; Miao, Ling; Ipsen, John Hjorth

    1996-01-01

    In this work we concentrate on phase equilibria in two-dimensional condensed systems of particles where both translational and internal degrees of freedom are present and coupled through microscopic interactions, with a focus on the manner of the macroscopic coupling between the two types...... where the spin degrees of freedom are slaved by the translational degrees of freedom and develop a first-order singularity in the order-disorder transition that accompanies the lattice-melting transition. The internal degeneracy of the spin states in model III implies that the spin order...

  19. Extended UNIQUAC model for correlation and prediction of vapour-liquid-solid equilibria in aqueous salt systems containing non-electrolytes

    DEFF Research Database (Denmark)

    Iliuta, Maria C.; Thomsen, Kaj; Rasmussen, Peter

    2000-01-01

    to aqueous salt systems containing non-electrolytes in order to demonstrate its ability in representing solid-liquid-vapour (SLV) equilibrium and thermal property data for these strongly non-ideal systems. The model requires only pure component and binary temperature-dependent interaction parameters....... The calculations are based on an extensive database consisting of salt solubility data in pure and mixed solvents, VLE data for solvent mixtures and mixed solvent-electrolyte systems and thermal properties for mixed solvent solutions. Application of the model to the methanol-water system in the presence of several...... ions (Na+, K+, NH4+, Cl-, NO3-, SO42-, CO2- and HCO3-) shows that the Extended UNIQUAC model is able to give an accurate description of VLE and SLE in ternary add quaternary mixtures, using the name set of binary interaction parameters. The capability of the model to predict accurately the phase...

  20. Bioligand-mediated partitioning of radionuclides to the aqueous phase

    International Nuclear Information System (INIS)

    Johnsson, A.; Pedersen, K.; Oedegaard-Jensen, A.; Jakobsson, A.M.; Ekberg, C.

    2008-01-01

    The aqueous-phase partitioning of 59 Fe, 147 Pm, 234 Th and 241 Am by complexing compounds from subsurface bacteria has previously been studied in the presence of quartz sand. In this study the aqueous-phase partitioning of pico- to submicromolar amounts of 59 Fe, 147 Pm, 234 Th and 241 Am was analyzed in the presence of TiO 2 and exudates from three species of subsurface bacteria: Pseudomonas fluorescens, Pseudomonas stutzeri, and Shewanella putrefaciens. All were grown under aerobic conditions and P. stutzeri and S. putrefaciens were grown under anaerobic conditions as well. The supernatants of the aerobic and anaerobic cultures were collected and radionuclide was added. TiO 2 , with BET surface area of 49.9 m 2 x g -1 , was added to the supernatant radionuclide mix, and the pH was adjusted to approximately 8. After incubation, the amount of radionuclide in the liquid phase of the samples and controls was analyzed using scintillation method. Two types of values were calculated: solution% = the activity maintained in solution relative to the total activity, and Q-values = the quotient between the activity in samples and the activity in controls. Aerobic supernatants had solution% values between 89% and 100% for 59 Fe and between 18 and 43% for 234 Th. The solution% values for 241 Am and 147 Pm were less than 2% overall, but the Q-values were between 34 and 115 times more 241 Am in bacterial supernatants than in controls. The corresponding values for 147 Pm ranged from 6 to 20 times more than in the control. The solution% values for all elements in the presence of anaerobic supernatants were below 2%, but the Q-values clustered around 7 for 59 Fe and ranging from 2 to 29 for 234 Th, indicated that anaerobic supernatants partitioned these elements to the aqueous phase. Both aerobic and anaerobic supernatants tested positive for complexing compounds when analyzed, using the Chrome Azurol S assay. Complexation with excreted organic ligands is most likely the reason

  1. Phase equilibria at low temperature for light hydrocarbons-methanol-water-acid gases mixtures: measurements and modelling; Equilibres de phases a basse temperature de systemes complexes CO{sub 2} - hydrocarbures legers - methanol - eau: mesures et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Ruffine, L.

    2005-10-15

    The need to develop and improve natural gas treatment processes is real. The petroleum industry usually uses separation processes which require phase equilibrium phenomena. Yet, the complexity of the phase equilibria involved results in a lack of data, which in turn limits the development of thermodynamic models. The first part of this work is devoted to experimental investigations for systems containing light hydrocarbons, methanol, water and acid gases. We present a new apparatus that was developed to measure vapor-liquid and vapor-liquid-liquid equilibria. It allowed us to obtain new phase composition data for the methanol-ethane binary system and different mixtures, and also to determine a part of the three phases equilibrium envelope of the same systems. In the second part of this work, we have developed a thermodynamic model based on the CPA equation of state. This choice may be justified by the presence of associating components like methanol, hydrogen sulfide and water in the systems. Such model is necessary for the design of gas treatment plants. Our model provides good results for phase equilibrium calculations for binaries systems without binary interaction parameter in many cases, and describes correctly the vapour-liquid and vapor-liquid-liquid equilibria for complex mixtures. (author)

  2. Phase equilibria modelling and zircon dating for Precambrian metapelites from Xinghuadukou Group in Lvlin Forest of Erguna Massif, NE China

    Science.gov (United States)

    Xu, Jiulei; Zheng, Changqing; Tajcmanova, Lucie; Zhong, Xin; Xu, Xuechun; Han, Xiaomeng; Wang, Zhaoyuan

    2017-04-01

    Xinghuadukou Group, the basement metamorphic complex of Erguna Massif in NE China, is considered to be Mesoproterozoic with Sm-Nd age of 1157±32 Ma. However, the new zircon data from these metamorphic supracrustal rocks in Lvlin Forest show that they formed in Neoproterozoic with the age of 800 Ma. Old zircon age with 2.5 Ga, 2.0 Ga and 1.8 Ga, indicate that the Erguna Massif had an affinity to both Columbia and Rodinia continents. Furthermore, we also present 500 Ma metamorphic age in micashists and 500 Ma age of adjacent granitoids that might have thermally influenced its surrounding. No detailed studies have been undertaken on the metamorphic evolution of the Xinghuadukou Complex. The typical paragneissic mineral assemblage of garnet sillimanite mica schist is Grt+Sil+Bt+Mus+Qtz±Kfs. (Zhou et al., 2011) proposed that the Xinghuadukou Complex appears to have undergone similar granulite facies metamorphic conditions based on the similarity of mineral assemblages to the Mashan Complex in the Jiamusi Massif, NE China. However, the new phase equilibria modelling result shows that these rocks are high amphibolite facies product with 650℃. We can easily find K-feldspar formed by partial melting due to the consuming of muscovite. Also the remaining muscovite is directly connected with a fluid channel in thin sections which indicate that the remaining muscovite formed from retrograde with the existence of fluid. The zoned garnet has low MgO and high CaO content in rims and high MgO and low CaO content in core. It seems that this garnet has high pressure and low temperature (HP-LT) in rims and low pressure and high temperature (LP-HT) in core which would point to an anti-clockwise metamorphic evolution. Zhou, J.B., Wilde, S.A., Zhang, X.Z., Zhao, G.C., Liu, F.L., Qiao, D.W., Ren, S.M. and Liu, J.H., 2011b. A> 1300km late Pan-African metamorphic belt in NE China: new evidence from the Xing'an block and its tectonic implications. Tectonophysics, 509(3): 280-292.

  3. Equilibres de phases dans les systèmes fluides petroliers-eau Phase Equilibria in Oil-Water Systems

    Directory of Open Access Journals (Sweden)

    Peneloux A.

    2006-11-01

    Full Text Available Nous présentons quelques résultats obtenus à partir du logiciel FHYD qui permet le traitement des mélanges eau-fluides pétroliers, avec la détermination de la nature des phases (huile-gaz-eau-hydrate thermodynamiquement stables dans des conditions données de température et de pression, ainsi que de la quantité, de la composition de ces différentes phases et de leurs propriétés. Ce logiciel permet le tracé automatique des diagrammes de phases et nous présentons des exemples, depuis les systèmes binaires (eau-éthane, ternaires (eau-méthane-propane jusqu'aux fluides les plus complexes. La présence de sels (chlorure de sodium dissous est envisagée, ainsi que le calcul des conditions de dépôt du sel solide. Des exemples de problèmes pétroliers sont cités (gaz de séparateur saturé en eau, huile saturée en eau dans les conditions de gisement, huile en présence d'eau salée. Les estimations sur les quantités d'hydrate formées et leurs compositions sont comparées à des données expérimentales et aux résultats obtenus par d'autres logiciels. Le programme FHYD pourrait permettre une représentation plus réaliste de l'évolution des fluides pétroliers et des propriétés de transport de leurs différentes phases dans les modèles de simulation des conduites polyphasiques. This article presents a selection of results obtained with the FHYD program. This software allows simulation of mixtures composed of petroleum fluids and water, with determination of the nature of thermodynamically stable phases (oil-gas-water-hydrate under given conditions of temperature and pressure, along with the quantity, composition and properties of these different phases. Additionally, the program can automatically produce phase diagrams. Several examples of these have been included here, ranging from binary systems (water-ethane and ternary systems (water-methane-propane to the most complex petroleum fluids. The presence of dissolved salts

  4. Modelling of phase equilibria in CH4–C2H6–C3H8–nC4H10–NaCl–H2O systems

    International Nuclear Information System (INIS)

    Li, Jun; Zhang, Zhigang; Luo, Xiaorong; Li, Xiaochun

    2015-01-01

    Highlights: • A new model was established for the phase equilibria of C1–C2–C3–nC4–brine systems. • The model can reproduce of hydrocarbon–brine equilibria to high T&P and salinity. • The model can well predict H 2 O solubility in light hydrocarbon rich phases. - Abstract: A thermodynamic model is presented for the mutual solubility of CH 4 –C 2 H 6 –C 3 H 8 –nC 4 H 10 –brine systems up to high temperature, pressure and salinity. The Peng–Robinson model is used for non-aqueous phase fugacity calculations, and the Pitzer model is used for aqueous phase activity calculations. The model can accurately reproduce the experimental solubilities of CH 4 , C 2 H 6 , C 3 H 8 and nC 4 H 10 in water or NaCl solutions and H 2 O solubility in the non-aqueous phase. The experimental data of mutual solubility for the CH 4 –brine subsystem are sufficient for temperatures exceeding 250 °C, pressures exceeding 1000 bar and NaCl molalities greater than 6 molal. Compared to the CH 4 –brine system, the mutual solubility data of C 2 H 6 –brine, C 3 H 8 –brine and nC 4 H 10 –brine are not sufficient. Based on the comparison with the experimental data of H 2 O solubility in C 2 H 6 -, C 3 H 8 - or nC 4 H 10 -rich phases, the model has an excellent capability for the prediction of H 2 O solubility in hydrocarbon-rich phases, as these experimental data were not used in the modelling. Predictions of hydrocarbon solubility (at temperatures up to 200 °C, pressures up to 1000 bar and NaCl molalities greater than 6 molal) were made for the C 2 H 6 –brine, C 3 H 8 –brine and nC 4 H 10 –brine systems. The predictions suggest that increasing pressure generally increases the hydrocarbon solubility in water or brine, especially in the lower-pressure region. Increasing temperature usually decreases the hydrocarbon solubility at lower temperatures but increases the hydrocarbon solubility at higher temperatures. Increasing water salinity dramatically decreases

  5. Photocathalytic degradation of organic micropollutants in aqueous phase

    International Nuclear Information System (INIS)

    Driussi, D.

    2009-01-01

    The aim of this study was to design, construct and test a small system for the photo catalytic degradation of organic micropollutants in aqueous phase using solar radiation. The system is a parabolic linear trough type with automatic one-axis (N-S) tracking of the apparent movement of the sun. The tracking algorithm foresees two dispositions of the collector named horizontal and polar, the last is necessary for installations in locations that are higher than 50 o in latitude. The idea that brought to mind this project was to offer the possibility of treat herbicides polluted waters by means of a simple system without using particular oxidizing chemicals (for example hydrogen peroxide) or components (for example mercury vapour UV lamps) and therefore in an eco-sustainable way. [it

  6. Aqueous phase oxidation techniques as an alternative to incineration

    International Nuclear Information System (INIS)

    Gray, L.W.; Adamson, M.G.; Hickman, R.G.; Farmer, J.C.; Chiba, Z.; Gregg, D.W.; Wang, F.T.

    1992-03-01

    The Lawrence Livermore National Laboratory (LLNL) has three aqueous phase techniques under development for oxidation of high value or high risk waste steams. One is direct electrochemical oxidation and one is mediated electrochemical oxidation utilizing regenerable, strongly oxidizing cations such as Ag(II), Co (III), Ce(IV), etc. These cations can either attack oxidizable materials directly and/or indirectly via first reacting with water to generate OH radicals which then attack the oxidizable materials. The third system utilizes H 2 O 2 and UV light to generate OH radicals directly which in turn attack the oxidizable materials. All systems have the advantage of a chemical off-switch in that when the power is turned off, the reaction quickly subsides. All systems operate with low concentrations (typically <5 wt %) of oxidizable materials, therefore, the stored energy for possible run-away reactions is very low. 15 figures, 22 references

  7. Heteroaggregation of graphene oxide with minerals in aqueous phase.

    Science.gov (United States)

    Zhao, Jian; Liu, Feifei; Wang, Zhenyu; Cao, Xuesong; Xing, Baoshan

    2015-03-03

    Upon release into waters, sediments, and soils, graphene oxide (GO) may interact with fine mineral particles. We investigated the heteroaggregation of GO with different minerals, including montmorillonite, kaolinite, and goethite, in aqueous phase. GO significantly enhanced the dispersion of positively charged goethite (>50%) via heteroaggregation, while there was no interaction between GO and negatively charged montmorillonite or kaolinite. Electrostatic attraction was the dominant force in the GO-goethite heteroaggregation (pH 4.0-8.5), and the dissolved Fe ions (formation of multilayered GO-goethite complex with high configurational stability. These findings are useful for understanding the interaction of GO with mineral surfaces, and potential fate and toxicity of GO under natural conditions in aquatic environments, as well as in soils and sediments.

  8. Phase equilibria of carbon dioxide and methane gas-hydrates predicted with the modified analytical S-L-V equation of state

    Directory of Open Access Journals (Sweden)

    Span Roland

    2012-04-01

    Full Text Available Gas-hydrates (clathrates are non-stoichiometric crystallized solutions of gas molecules in the metastable water lattice. Two or more components are associated without ordinary chemical union but through complete enclosure of gas molecules in a framework of water molecules linked together by hydrogen bonds. The clathrates are important in the following applications: the pipeline blockage in natural gas industry, potential energy source in the form of natural hydrates present in ocean bottom, and the CO2 separation and storage. In this study, we have modified an analytical solid-liquid-vapor equation of state (EoS [A. Yokozeki, Fluid Phase Equil. 222–223 (2004] to improve its ability for modeling the phase equilibria of clathrates. The EoS can predict the formation conditions for CO2- and CH4-hydrates. It will be used as an initial estimate for a more complicated hydrate model based on the fundamental EoSs for fluid phases.

  9. MINTEQ, Geochemical Equilibria in Ground Water

    International Nuclear Information System (INIS)

    Krupka, K.M.

    1990-01-01

    1 - Description of program or function: MINTEQ is a geochemical program to model aqueous solutions and the interactions of aqueous solutions with hypothesized assemblages of solid phases. It was developed for the Environmental Protection Agency to perform the calculations necessary to simulate the contact of waste solutions with heterogeneous sediments or the interaction of ground water with solidified wastes. MINTEQ can calculate ion speciation/solubility, adsorption, oxidation-reduction, gas phase equilibria, and precipitation/dissolution of solid phases. MINTEQ can accept a finite mass for any solid considered for dissolution and will dissolve the specified solid phase only until its initial mass is exhausted. This ability enables MINTEQ to model flow-through systems. In these systems the masses of solid phases that precipitate at earlier pore volumes can be dissolved at later pore volumes according to thermodynamic constraints imposed by the solution composition and solid phases present. The ability to model these systems permits evaluation of the geochemistry of dissolved traced metals, such as low-level waste in shallow land burial sites. MINTEQ was designed to solve geochemical equilibria for systems composed of one kilogram of water, various amounts of material dissolved in solution, and any solid materials that are present. Systems modeled using MINTEQ can exchange energy and material (open systems) or just energy (closed systems) with the surrounding environment. Each system is composed of a number of phases. Every phase is a region with distinct composition and physically definable boundaries. All of the material in the aqueous solution forms one phase. The gas phase is composed of any gaseous material present, and structurally distinct solid forms a separate phase. 2 - Method of solution: MINTEQ applies the fundamental principles of thermodynamics to solve geochemical equilibria from a set of mass balance equations, one for each component. Because the

  10. Spontaneous vesicle phase formation by pseudogemini surfactants in aqueous solutions.

    Science.gov (United States)

    Sun, Nan; Shi, Lijuan; Lu, Fei; Xie, Shuting; Zheng, Liqiang

    2014-08-14

    The phase behavior of a kind of pseudogemini surfactant in aqueous solutions, formed by the mixture of sodium dodecyl benzene sulfonate (SDBS) and butane-1,4-bis (methylimidazolium bromide) ([mim-C4-mim]Br2) or butane-1,4-bis(methylpyrrolidinium bromide) ([mpy-C4-mpy]Br2) in a molar ratio of 2 : 1, is reported in the present work. When [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 is mixed with SDBS in aqueous solutions, one cationic [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 molecule "bridges" two SDBS molecules by noncovalent interactions (e.g. electrostatic, π-π stacking, and σ-π interactions), behaving like a pseudogemini surfactant. Vesicles can be formed by this kind of pseudogemini surfactant, determined by freeze-fracture transmission electron microscopy (FF-TEM) or cryogenic-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). The mixed system of sodium dodecyl sulfate (SDS) with [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 was also constructed, and only micelles were observed. We infer that a pseudogemini surfactant is formed under the synergic effect of electrostatic, π-π stacking, and σ-π interactions in the SDBS/[mim-C4-mim]Br2/H2O system, while electrostatic attraction and hydrophobic interactions may provide the directional force for vesicle formation in the SDBS/[mpy-C4-mpy]Br2/H2O system.

  11. Attractive evolutionary equilibria

    OpenAIRE

    Roorda, Berend; Joosten, Reinoud

    2011-01-01

    We present attractiveness, a refinement criterion for evolutionary equilibria. Equilibria surviving this criterion are robust to small perturbations of the underlying payoff system or the dynamics at hand. Furthermore, certain attractive equilibria are equivalent to others for certain evolutionary dynamics. For instance, each attractive evolutionarily stable strategy is an attractive evolutionarily stable equilibrium for certain barycentric ray-projection dynamics, and vice versa.

  12. High pressure study of water-salt systems, phase equilibria, partitioning, thermodynic properties and implication for large icy worlds hydrospheres.

    Science.gov (United States)

    Journaux, B.; Brown, J. M.; Abramson, E.; Petitgirard, S.; Pakhomova, A.; Boffa Ballaran, T.; Collings, I.

    2017-12-01

    Water salt systems are predicted to be present in deep hydrosphere inside water-rich planetary bodies, following water/rock chemical interaction during early differentiation stages or later hydrothermal activity. Unfortunately the current knowledge of the thermodynamic and physical properties of aqueous salt mixtures at high pressure and high temperature is still insufficient to allow realistic modeling of the chemical or dynamic of thick planetary hydrospheres. Recent experimental results have shown that the presence of solutes, and more particularly salts, in equilibrium with high pressure ices have large effects on the stability fields, buoyancy and chemistry of all the phases present at these extreme conditions. Effects currently being investigated by our research group also covers ice melting curve depressions that depend on the salt species and incorporation of solutes inside the crystallographic lattice of high pressure ices. Both of these could have very important implication at the planetary scale, enabling thicker/deeper liquid oceans, and allowing chemical transportation through the high pressure ice layer in large icy worlds. We will present the latest results obtained in-situ using diamond anvil cell, coupled with Synchrotron X-Ray diffraction, Raman Spectroscopy and optical observations, allowing to probe the crystallographic structure, equations of state, partitioning and phase boundary of high pressure ice VI and VII in equilibrium with Na-Mg-SO4-Cl ionic species at high pressures (1-10 GPa). The difference in melting behavior depending on the dissolved salt species was characterized, suggesting differences in ionic speciation at liquidus conditions. The solidus P-T conditions were also measured as well as an increase of lattice volumes interpreted as an outcome of ionic incorporation in HP ice during incongruent crystallization. The measured phase diagrams, lattice volumes and important salt incorporations suggest a more complex picture of the

  13. Bioconversion of apigenin-7-O-β-glucoside in aqueous two-phase system

    Directory of Open Access Journals (Sweden)

    Ilić Sanja M.

    2005-01-01

    Full Text Available The study is concerned with the conversion of apigenin-7-O-β-glucoside into apigenin in polyethylene glycol 6000 / dextran 20000 aqueous two-phase system by β-glucosidase. Apigenin was separated from apigenin-7-O-β-glucoside and β-glucosidase by their partition into opposite phases. In 14% PEG / 22.5% DEX aqueous two-phase system obtained yield of apigenin in top phase was 108%.

  14. (Liquid + liquid) equilibria for (water + 1-propanol or acetone + β-citronellol) at different temperatures

    International Nuclear Information System (INIS)

    Li, Hengde; Han, Yongtao; Huang, Cheng; Yang, Chufen

    2015-01-01

    Graphical abstract: (Liquid + liquid) equilibrium data for systems composed of β-citronellol and aqueous 1-propanol or acetone are presented. Distribution ratios of 1-propanol and acetone in the mixtures are examined. The effect of the temperature on the ternary (liquid + liquid) equilibria is evaluated and discussed. - Highlights: • Ternary (liquid + liquid) equilibria containing β-citronellol are presented. • Distribution ratios of 1-propanol and acetone in the mixtures are examined. • The effect on the temperature of the systems is evaluated and discussed. - Abstract: On this paper, experimental (liquid + liquid) equilibrium (LLE) results are presented for systems composed of β-citronellol and aqueous 1-propanol or acetone. To evaluate the phase separation properties of β-citronellol in aqueous mixtures, LLE values for the ternary systems (water + 1-propanol + β-citronellol) and (water + acetone + β-citronellol) were determined with a tie-line method at T = (283.15, 298.15, and 313.15 ± 0.02) K and atmospheric pressure. The reliability of the experimental tie-lines was verified by the Hand and Bachman equations. Ternary phase diagrams, distribution ratios of 1-propanol and acetone in the mixtures are shown. The effect of the temperature on the ternary (liquid + liquid) equilibria was examined and discussed. The experimental LLE values were satisfactorily correlated by extended UNIQUAC and modified UNIQUAC models

  15. Ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography.

    Science.gov (United States)

    Pesek, Joseph J; Matyska, Maria T

    2015-07-03

    The use of ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography with silica hydride-based stationary phases and mass spectrometry detection is evaluated. Retention times, peak shape, efficiency and peak intensity are compared to the more standard additives formic acid and ammonium formate. The test solutes were NAD, 3-hydroxyglutaric acid, α-ketoglutaric acid, p-aminohippuric acid, AMP, ATP, aconitic acid, threonine, N-acetyl carnitine, and 3-methyladipic acid. The column parameters are assessed in both the positive and negative ion detection modes. Ammonium fluoride is potentially an aggressive mobile phase additive that could have detrimental effects on column lifetime. Column reproducibility is measured and the effects of switching between different additives are also tested. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Flocculation kinetics of kaolinite : role of aqueous phase species

    Energy Technology Data Exchange (ETDEWEB)

    House, P.; Wang, C.; Dhadli, N. [Shell Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    Flocculation kinetics were used to study the rate-based processes that lead to aggregate growth and breakage of kaolinite in oil sands tailings. The role of aqueous phase species on aggregate growth, breakage and flocculant de-activation was studied. Collision efficiency and deactivation parameters were presented. The study showed that collisions can be efficient when the adsorption of the polymer is thermodynamically favorable. Up to 94 percent of adsorption takes place at the kaolinite edge. Studies have shown that hydrogen bonding sites on the kaolinite disappear with increases in pH values. The impact of molecular level interactions on flocculation kinetics were assessed in order to determine collision efficiencies and aggregate breakage rates. A focused beam reflectance model was used to monitor flocculation kinetics in situ. The period over which reflectance was observed was coupled with the laser velocity to determine the chord length of the particle. The kinetics of flocculation were observed for a 10 minute period. The effects of pH, calcium additions, and EDTA chelating agent additions were investigated. The study showed that calcium additions accelerate the rate of flocculant growth dramatically, and provide a much higher collision efficiency. Flocculants formed in the presence of calcium were weaker. The presence of salts promoted polymer adsorption by non-specific Van der Waals forces. tabs., figs.

  17. Hydrogen production by aqueous phase catalytic reforming of glycerine

    International Nuclear Information System (INIS)

    Ozguer, Derya Oncel; Uysal, Bekir Zuehtue

    2011-01-01

    Hydrogen is believed to be the one of the main energy carriers in the near future. In this research glycerine, which is produced in large quantities as a by-product of biodiesel process, was converted to hydrogen aiming to contribute to clean energy initiative. Conversion of glycerol to hydrogen was achieved via aqueous-phase reforming (APR) with Pt/Al 2 O 3 catalyst. The experiments were carried out in an autoclave reactor and a continuous fixed-bed reactor. The effects of reaction temperature (160-280 o C), feed flow rate (0.05-0.5 mL/dak) and feed concentration (5-85 wt-% glycerine) on product distribution were investigated. Optimum temperature for hydrogen production with APR was determined as 230 o C. Maximum gas production rate was found at the feed flow rates around 0.1 mL/min. It was also found that hydrogen concentration in the gas product increased with decreasing glycerol concentration in the feed.

  18. Phase Behavior of Aqueous NA-K-MG-CA-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

    Energy Technology Data Exchange (ETDEWEB)

    M.S. Gruszkiewiez; D.A. Palmer; R.D. Springer; P. Wang; A. Anderko

    2006-09-14

    A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems.

  19. Spinel + quartz-bearing ultrahigh-temperature granulites from Xumayao, Inner Mongolia Suture Zone, North China Craton: Petrology, phase equilibria and counterclockwise p-T path

    Directory of Open Access Journals (Sweden)

    Huatian Zhang

    2012-09-01

    Our phase equilibria modeling indicates two main stages during the metamorphic evolution of these rocks: 1 near-isobaric cooling from 975 °C to 875 °C around 8 kbar, represented by the formation of garnet porphyroblasts from spinel and quartz; and 2 cooling and decompression from 850 °C, 8 kbar to below 750 °C, 6.5 kbar, represented by the break-down of garnet. The spinel + quartz assemblage is considered to have been stable at peak metamorphism, formed through the break-down of cordierite, indicating a near isothermal compression process. Our study confirms the regional extent of UHT metamorphism within the IMSZ associated with the Paleoproterozoic subduction-collision process.

  20. Modeling phase equilibria of alkanols with the simplified PC-SAFT equation of state and generalized pure compound parameters

    DEFF Research Database (Denmark)

    Grenner, Andreas; Kontogeorgis, Georgios; von Solms, Nicolas

    2007-01-01

    The simplified PC-SAFT equation of state has been applied to liquid-liquid, vapor-liquid and solid-liquid equilibria for mixtures containing 1-or 2-alkanols with alkanes, aromatic hydrocarbons, CO2 and water. For the alkanols we use generalized pure compound parameters. This means that two...... of the physical pure compound parameters, in (segment number) and or (segment diameter), are obtained from linear extrapolations, since m and m sigma(3), increase linearly with respect to the molar mass, and moreover, the two association parameters (association energy and association volume) were assumed...... to be constant for all alkanols. Only the dispersion energy is fitted to experimental data. Thus it is possible to estimate parameters for several 1-and 2-alkanols. The final aim is to develop a group contribution approach for PC-SAFT which is suitable for complex compounds, considering that the motivation...

  1. Evaluation of the polysubstituted pyridinium ionic liquid [hmmpy][Ntf2] as a suitable solvent for desulfurization: Phase equilibria

    International Nuclear Information System (INIS)

    Arce, Alberto; Francisco, Maria; Soto, Ana

    2010-01-01

    Suitability of a pyridinium ionic liquid as a solvent in desulfurization has been analyzed. (Liquid + liquid) equilibria for ternary systems composed by 1-hexyl-3,5-dimethyl pyridinium {bis[trifluoromethylsulfonyl]imide, thiophene, and three hydrocarbons representative of fuel (n-heptane, 2,2,4 trimethylpentane, and toluene) have been determined at T = 298.15 K and atmospheric pressure. High solubility of thiophene in the ionic liquid and also of toluene have been found, being this solvent practically immiscible with 2,2,4 trimethylpentane and heptane. Equilibrium data of these systems have been well correlated with UNIQUAC equations finding the highest deviations for the ternary system involving toluene. NRTL model drove to worse results being considered as not suitable model to correlate the experimental results.

  2. Development of long-lived radionuclides partitioning technology - Experimental/theoretical study of phase equilibria for multicomponent multiphase systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chul Soo; Lee, Se Il; Sim, Yeon Sik; Park, Sung Bin; Yang, Sung Oh; Park, Ji Yong [Korea University, Seoul (Korea, Republic of)

    1995-08-01

    In various partitioning processes, rare earth elements and actinide elements are separated from other elements in the first stage. They are then separated into rare earth groups and actinde groups. The first stage is accomplished by solvent extraction using DEHPA, by precipitation using oxalic= acid, or by cation exchange. The second stage is carried out by selective back-extraction or by selective elution using DTPA. In these processes the equilibria is governed by the concentrations of nitric acid, of solvents, and of precipitants among others. In this study various distribution coefficients in partitioning processes were experimentally determined. And thermodynamic models were proposed to calculate distribution coefficients with experimentally determined equilibrium constants. 32 refs., 11 tabs., 23 figs. (author)

  3. Two-phase aqueous micellar systems: an alternative method for protein purification

    Directory of Open Access Journals (Sweden)

    Rangel-Yagui C. O.

    2004-01-01

    Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

  4. Thermophysical properties and phase equilibria study of the binary systems {l_brace}N-hexylquinolinium bis(trifluoromethylsulfonyl)imide + aromatic hydrocarbons, or an alcohol{r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula, E-mail: ula@ch.pw.edu.p [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Thermodynamic Research Unit, School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4001 (South Africa); Zawadzki, Maciej [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Zwolinska, Magdalena [Department of Ergonomics, Laboratory of Thermal Loads, Central Institute for Labour Protection-National Research Institute, Czerniakowska 16, 00-701 Warsaw (Poland)

    2011-05-15

    Research highlights: We synthesized new ionic liquid, [HQuin][NTf{sub 2}] with low viscosity, and low density. We found high heat capacity, high enthalpy of melting and low melting temperature. HQuin][NTf{sub 2}] is proposed for possible use in the phase change materials (PCM). We examine phase equilibrium changes, SLE and LLE with hydrocarbons and alcohols. [HQuin][NTf{sub 2}] may be proposed as entrainer for the separation proceses. - Abstract: The new quinolinium ionic liquid has been synthesised as a continuation of our work with quinolinium-based ionic liquids (ILs). The work includes specific basic characterisation of synthesized compounds: N-hexylquinolinium bromide, [HQuin][Br] and N-hexylquinolinium bis{l_brace}(trifluoromethyl)sulfonyl{r_brace}imide [HQuin][NTf{sub 2}] by NMR spectra, elementary analysis and water content. The basic thermal properties of the pure [HQuin][NTf{sub 2}] i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity have been measured using a differential scanning microcalorimetry technique (DSC) and thermal analysis instrument (TA). Densities and viscosities were determined as a function of temperature. Phase equilibria for the binary systems: {l_brace}[HQuin][NTf{sub 2}]) + aromatic hydrocarbon (benzene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol){r_brace} have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (270 to 320) K. For all the binary systems with benzene and alkylbenzenes, the eutectic diagrams were observed with immiscibility gap in the liquid phase beginning from (0.13 to 0.28) mole fraction of the IL with very high an upper critical solution temperature (UCST). For mixtures with alcohols, the complete miscibility was observed for 1-butanol and immiscibility with UCST in the liquid phase for the remaining alcohols. The typical

  5. Study of phase equilibria in function of temperature in UO2-PuO2-Pu2O3 system for nuclear ceramics with high plutonium contents

    International Nuclear Information System (INIS)

    Truphemus, Thibaut

    2013-01-01

    In the UO 2 -PuO 2 -Pu 2 O 3 section, a monophasic (U 1-y ,Pu y )O 2-x domain is stable for y≤0,20 at 25 C and up to solid-liquid equilibrium. At higher Pu content, phase equilibria are more unclear with a phase separation process. The main objective of this work consisted in upgrading the representation of this system for 0,15≤y≤0,65 and 25≤T(C)≤1500. At 25 C, a miscibility gap composed by two different (U 1-y ,Pu y )O 2-x phases has been observed for y≤0,45, with one very closed to stoichiometric state (Oxygen/Metal=2) and one other very reduced. For the first time, a triphasic domain has been characterized at higher Pu contents, with two (U 1-y ,Pu y )O 2-x phases near y=0,45 and one (U 1-y ,Pu y ) 2 O 3 phase with a low U content inside. Concerning the study in function of temperature, we have demonstrated that phase separation temperature increase when Pu content grows. Several representations have been established. At 200 C, the representation is closed to that at 25 C. At 400 C, the phase separation have been specified at a lower Pu content than that of literature: y=0,35. At 600 C, our results have clarified the section, until then very unclear, with a phase separation appearing at y=0,60.The microstructural analysis has clearly demonstrated the significant impact of the phase separation on the material. Indeed many cracks have been observed in our samples, and quantity of these defects increases when Pu content grows. (author) [fr

  6. The Al-rich region of the Al-Mn-Ni alloy system. Part II. Phase equilibria at 620-1000 oC

    International Nuclear Information System (INIS)

    Balanetskyy, S.; Meisterernst, G.; Grushko, B.; Feuerbacher, M.

    2011-01-01

    Research highlights: → Phase equilibria in the Al-rich region of the Al-Mn-Ni alloy system were studied at 1000, 950, 850, 750, 700, 645 and 620 deg. C by means of SEM, TEM, powder XRD and DTA. → Three ternary thermodynamically stable intermetallics, the φ-phase (Al 5 Co 2 -type, hP26, P63/mmc; a = 0.76632(16), c = 0.78296(15) nm), the κ-phase (κ-Al 14.4 Cr 3.4 Ni l.1 -type, hP227, P63/m; a = 1.7625(10), c = 1.2516(10) nm), and the O-phase (O-Al 77 Cr 14 Pd 9 -type, Pmmn, oP650,: a = 2.3316(16), b = 1.2424(15), c = 3.2648(14) nm), as well as three ternary metastable phases, the decagonal D 3 -phase with periodicity about 1.25 nm, the Al 9 (Mn,Ni) 2 -phase (Al 9 Co 2 -type, P1121/a, mP22; a = 0.8585(16), b = 0.6269(9), c = 0.6205(11) nm, β = 95.34(10) o ) and the O 1 -phase (basecentered orthorhombic, a ∼ 23.8, b ∼ 12.4, c ∼ 32.2 nm) were revealed. → The existence of a thermodynamically stable R-phase of stoichiometry Al 60 Mn 11 Ni 4 , reported earlier in literature, was not confirmed in the present study. - Abstract: Phase equilibria in the Al-rich region of the Al-Mn-Ni alloy system were studied at 1000, 950, 850, 750, 700, 645 and 620 o C. Three ternary thermodynamically stable intermetallics, the φ-phase (Al 5 Co 2 -type, hP26, P6 3 /mmc; a = 0.76632(16), c = 0.78296(15) nm), the κ-phase (κ-Al 14.4 Cr 3.4 Ni l.1 -type, hP227, P6 3 /m; a = 1.7625(10), c = 1.2516(10) nm), and the O-phase (O-Al 77 Cr 14 Pd 9 -type, Pmmn, oP650,: a = 2.3316(16), b = 1.2424(15), c = 3.2648(14) nm), as well as three ternary metastable phases, the decagonal D 3 -phase with periodicity about 1.25 nm, the Al 9 (Mn,Ni) 2 -phase (Al 9 Co 2 -type, P112 1 /a, mP22; a = 0.8585(16), b = 0.6269(9), c = 0.6205(11) nm, β = 95.34(10) o ) and the O 1 -phase (base-centered orthorhombic, a ∼ 23.8, b ∼ 12.4, c ∼ 32.2 nm) were revealed. Their physicochemical behaviour in the Al-Mn-Ni alloy system was studied.

  7. IONS FROM AQUEOUS PHASE BY WATER HYACINTH (Eichhornia

    African Journals Online (AJOL)

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    Most often there is incomplete metal ion removal, high reagent and ... environmentally friendly water filters for heavy metal ions removal in aqueous systems. Currently E. crassipes is ..... From the results, the singly charged ions have very little ...

  8. (Vapour + liquid) equilibria, volumetric and compressibility behaviour of binary and ternary aqueous solutions of 1-hexyl-3-methylimidazolium chloride, methyl potassium malonate, and ethyl potassium malonate

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Mahdavi, Adibeh

    2012-01-01

    Highlights: ► VLE and volumetry of binary and ternary [C 6 mim][Cl], MPM and EPM aqueous solutions. ► Constant a w lines show small negative deviation from the linear isopiestic relation. ► Solute–water interactions follow the order: EPM > MPM > [C 6 mim][Cl]. ► MPM and EPM have a very weak salting-out effect on [C 6 mim][Cl] aqueous solutions. - Abstract: (Vapour + liquid) equilibrium data (water activity, vapour pressure, osmotic coefficient, and activity coefficient) of binary aqueous solutions of 1-hexyl-3-methylimidazolium chloride ([C 6 mim][Cl]), methyl potassium malonate, and ethyl potassium malonate and ternary {[C 6 mim][Cl] + methyl potassium malonate} and {[C 6 mim][Cl] + ethyl potassium malonate} aqueous solutions were obtained through the isopiestic method at T = 298.15 K. These results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solutions at molality about 0.4 mol · kg −1 . The constant water activity lines of all the ternary systems investigated show small negative deviations from the linear isopiestic relation (Zdanovskii–Stokes–Robinson rule) derived using the semi-ideal hydration model. The density and speed of sound measurements were carried out on solutions of methyl potassium malonate and ethyl potassium malonate in water and of [C 6 mim][Cl] in aqueous solutions of 0.25 mol · kg −1 methyl potassium malonate and ethyl potassium malonate at T = (288.15 to 308.15) K at atmospheric pressure. From the experimental density and speed of sound data, the values of the apparent molar volume, apparent molar isentropic compressibility and excess molar volume were evaluated and from which the infinite dilution apparent molar volume and infinite dilution apparent molar isentropic compressibility were calculated at each temperature. Although, there are no clear differences between the values of the apparent molar volume of [C 6 mim][Cl] in pure water and in methyl potassium malonate or ethyl

  9. Reversible, on-demand generation of aqueous two-phase microdroplets

    Science.gov (United States)

    Collier, Charles Patrick; Retterer, Scott Thomas; Boreyko, Jonathan Barton; Mruetusatorn, Prachya

    2017-08-15

    The present invention provides methods of on-demand, reversible generation of aqueous two-phase microdroplets core-shell microbeads, microparticle preparations comprising the core-shell microbeads, and drug delivery formulation comprising the microparticle preparations. Because these aqueous microdroplets have volumes comparable to those of cells, they provide an approach to mimicking the dynamic microcompartmentation of biomaterial that naturally occurs within the cytoplasm of cells. Hence, the present methods generate femtoliter aqueous two-phase droplets within a microfluidic oil channel using gated pressure pulses to generate individual, stationary two-phase microdroplets with a well-defined time zero for carrying out controlled and sequential phase transformations over time. Reversible phase transitions between single-phase, two-phase, and core-shell microbead states are obtained via evaporation-induced dehydration and water rehydration.

  10. Simultaneous Extraction, Enrichment and Removal of Dyes from Aqueous Solutions Using a Magnetic Aqueous Micellar Two-Phase System

    Directory of Open Access Journals (Sweden)

    Shuanggen Wu

    2017-12-01

    Full Text Available The magnetic aqueous micellar two-phase system (MAMTPS has the advantages combined of magnetic solid phase extraction (MSPE and aqueous micellar two-phase system (AMTPS. Thus, MAMTPS based on Fe3O4 magnetic nanoparticles (MNPs and a nonionic surfactant Triton X-114 (TX-114 was developed for the extraction, enrichment and removal of three dyes (Congo red, methyl blue, and methyl violet from aqueous solutions in this study. The MNPs Fe3O4@NH2 was screened as the optimal MNPs benefiting the extraction. Then, the influencing factors of MNPs amount, TX-114 concentration, vibration time, and extraction temperature were investigated in detail. The results showed that the extraction efficiencies of three dyes almost reached 100% using MAMTPS under the optimal conditions; MAMTPS had higher extraction ability than the individual MSPE or AMTPS. Thus, MAMTPS had the advantages of simple operation, high extraction ability, easy recycling of MNPs, and short phase-separation time, which showspotential for use in the extraction and analysis of contaminants from water samples.

  11. Hydrogen production through aqueous-phase reforming of ethylene glycol in a washcoated microchannel

    NARCIS (Netherlands)

    Neira d'Angelo, M.F.; Ordomskiy, V.; Paunovic, V.; Schaaf, van der J.; Schouten, J.C.; Nijhuis, T.A.

    2013-01-01

    Aqueous-phase reforming (APR) of biocarbohydrates is conducted in a catalytically stable washcoated microreactor where multiphase hydrogen removal enhances hydrogen efficiency. Single microchannel experiments are conducted following a simplified model based on the microreactor concept. A coating

  12. The heat capacity of a natural monticellite and phase equilibria in the system CaO-MgO-SiO2-CO2

    Science.gov (United States)

    Sharp, Z.D.; Essene, E.J.; Anovitz, Lawrence M.; Metz, G.W.; Westrum, E.F.; Hemingway, B.S.; Valley, J.W.

    1986-01-01

    The heat capacity of a natural monticellite (Ca1.00Mg.09Fe.91Mn.01Si0.99O3.99) measured between 9.6 and 343 K using intermittent-heating, adiabatic calorimetry yields Cp0(298) and S2980 of 123.64 ?? 0.18 and 109.44 ?? 0.16 J ?? mol-1 K-1 respectively. Extrapolation of this entropy value to end-member monticellite results in an S0298 = 108.1 ?? 0.2 J ?? mol-1 K-1. High-temperature heat-capacity data were measured between 340-1000 K with a differential scanning calorimeter. The high-temperature data were combined with the 290-350 K adiabatic values, extrapolated to 1700 K, and integrated to yield the following entropy equation for end-member monticellite (298-1700 K): ST0(J ?? mol-1 K-1) = S2980 + 164.79 In T + 15.337 ?? 10-3 T + 22.791 ?? 105 T-2 - 968.94. Phase equilibria in the CaO-MgO-SiO2 system were calculated from 973 to 1673 K and 0 to 12 kbar with these new data combined with existing data for akermanite (Ak), diopside (Di), forsterite (Fo), merwinite (Me) and wollastonite (Wo). The location of the calculated reactions involving the phases Mo and Fo is affected by their mutual solid solution. A best fit of the thermodynamically generated curves to all experiments is made when the S0298 of Me is 250.2 J ?? mol-1 K-1 less than the measured value of 253.2 J ?? mol-1 K-1. A best fit to the reversals for the solid-solid and decarbonation reactions in the CaO-MgO-SiO2-CO2 system was obtained with the ??G0298 (kJ ?? mole-1) for the phases Ak(-3667), Di(-3025), Fo(-2051), Me(-4317) and Mo(-2133). The two invariant points - Wo and -Fo for the solid-solid reactions are located at 1008 ?? 5 K and 6.3 ?? 0.1 kbar, and 1361 ?? 10 K and 10.2 ?? 0.2 kbar respectively. The location of the thermodynamically generated curves is in excellent agreement with most experimental data on decarbonation equilibria involving these phases. ?? 1986.

  13. Phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC and the formation of TiC in Fe3Al-based alloys

    International Nuclear Information System (INIS)

    Kobayashi, Satoru; Schneider, Andre; Zaefferer, Stefan; Frommeyer, Georg; Raabe, Dierk

    2005-01-01

    In the context of the development of high-strength Fe 3 Al-based alloys, phase equilibria among α-Fe(Al, Cr, Ti), liquid and TiC phases in the Fe-Al-Cr-Ti-C quinary system and the formation of TiC were determined. A pseudo-eutectic trough (L α + L + TiC) exists at 1470 deg C at around Fe-26Al-5Cr-2Ti-1.7C on the vertical section between Fe-26Al-5Cr (α) and Ti-46C (TiC) in at.%. Large faceted TiC precipitates form from the melt after the formation of primary α phase even in hypoeutectic alloys. The TiC formation is thought to be due to the composition change of the liquid towards the hypereutectic compositions by solidification of the primary α. In order to remove the faceted TiC, which are unfavourable for strengthening the material, two different processing routes have been successfully tested: (i) solidification with an increased rate to reduce the composition variation of the liquid during solidification, and (ii) unidirectional solidification to separate the light TiC precipitates from the melt

  14. Prediction of liquid-liquid equilibria for polyethylene glycol based aqueous two-phase system by ASOG and UNIFAC method

    Directory of Open Access Journals (Sweden)

    M. Perumalsamy

    2009-03-01

    Full Text Available Liquid-Liquid equilibrium data were obtained for the polyethylene glycol2000(PEG2000-sodium citrate-water system at 298.15, 308.15 and 318.15 K. The effect of temperature on binodal and tie line data was studied and published in a previous article (Murugesan and Perumalsamy, 2005. The interaction parameters of ASOG and UNIFAC models were estimated using the LLE data of PEG2000-sodium citrate-water system and are used to predict the LLE data for PEG6000-sodium citrate-water system at 298.15, 308.15 and 318.15 K (literature data. The predicted LLE data by both ASOG and UNIFAC models showed good agreement with the experimental and literature data.

  15. Phase Equilibria of the Ternary Sn-Pb-Co System at 250°C and Interfacial Reactions of Co with Sn-Pb Alloys

    Science.gov (United States)

    Wang, Chao-hong; Kuo, Chun-yi; Yang, Nian-cih

    2015-11-01

    The isothermal section of the ternary Sn-Pb-Co system at 250°C was experimentally determined through a series of the equilibrated Sn-Pb-Co alloys of various compositions. The equilibrium phases were identified on the basis of compositional analysis. For the Sn-Co intermetallic compounds (IMCs), CoSn3, CoSn2, CoSn and Co3Sn2, the Pb solubility was very limited. There exist five tie-triangle regions. The Co-Pb system involves one monotectic reaction, so the phase separation of liquid alloys near the Co-Pb side occurred prior to solidification. The immiscibility field was also determined. Additionally, interfacial reactions between Co and Sn-Pb alloys were conducted. The reaction phase for the Sn-48 at.%Pb and Sn-58 at.%Pb at 250°C was CoSn3 and CoSn2, respectively. Both of them were simultaneously formed in the Sn-53 at.%Pb/Co. The formed IMCs were closely associated to the phase equilibria relationship of the liquid-CoSn3-CoSn2 tie-triangle. Furthermore, with increasing temperatures, the phase formed in equilibrium with Sn-37 wt.%Pb was found to transit from CoSn3 to CoSn2 at 275°C. We propose a simple method of examining the phase transition temperature in the interfacial reactions to determine the boundaries of the liquid-CoSn3-CoSn2 tie-triangles at different temperatures.

  16. Water structure and aqueous uranyl(VI) adsorption equilibria onto external surfaces of beidellite, montmorillonite, and pyrophyllite: results from molecular simulations.

    Science.gov (United States)

    Greathouse, Jeffery A; Cygan, Randall T

    2006-06-15

    Molecular dynamics simulations were performed to provide a systematic study of aqueous uranyl adsorption onto the external surface of 2:1 dioctahedral clays. Our understanding of this key process is critical in predicting the fate of radioactive contaminants in natural groundwaters. These simulations provide atomistic detail to help explain experimental trends in uranyl adsorption onto natural media containing smectite clays. Aqueous uranyl concentrations ranged from 0.027 to 0.162 M. Sodium ions and carbonate ions (0.027-0.243 M) were also present in the aqueous regions to more faithfully model a stream of uranyl-containing groundwater contacting a mineral system comprised of Na-smectite. No adsorption occurred near the pyrophyllite surface, and there was little difference in uranyl adsorption onto the beidellite and montmorillonite, despite the difference in location of clay layer charge between the two. At low uranyl concentration, the pentaaquouranyl complex dominates in solution and readily adsorbs to the clay basal plane. At higher uranyl (and carbonate) concentrations, the mono(carbonato) complex forms in solution, and uranyl adsorption decreases. Sodium adsorption onto beidellite occurred both as inner- and outer-sphere surface complexes, again with little effect on uranyl adsorption. Uranyl surface complexes consisted primarily of the pentaaquo cation (85%) and to a lesser extent the mono(carbonato) species (15%). Speciation diagrams of the aqueous region indicate that the mono(carbonato)uranyl complex is abundant at high ionic strength. Oligomeric uranyl complexes are observed at high ionic strength, particularly near the pyrophyllite and montmorillonite surfaces. Atomic density profiles of water oxygen and hydrogen atoms are nearly identical near the beidellite and montmorillonite surfaces. Water structure therefore appears to be governed by the presence of adsorbed ions and not by the location of layer charge associated with the substrate. The water

  17. Pinning of phase separation of aqueous solution of hydroxypropylmethylcellulose by gelation

    Science.gov (United States)

    Kita, Rio; Kaku, Takeshi; Kubota, Kenji; Dobashi, Toshiaki

    1999-08-01

    Opalescence of the aqueous solution of hydroxypropylmethylcellulose (HPMC) induced by heating has been studied in terms of the phase diagram and the phase separation dynamics. The cloud point curve and the sol-to-gel transition curve intersected with each other at about 55 °C. Just above the cloud-point curve at which the spinodal curve has its minimum, a ring-like scattering pattern appeared corresponding to the spinodal decomposition. Temporal growth of the scattering function in the course of phase separation was studied by a time-resolved light scattering technique. The gelation pinned the phase separation (spinodal decomposition) of the aqueous HPMC solution.

  18. The experimental investigation of phase equilibria in the Al-rich corner within the ternary Al–Mn–Be system

    Energy Technology Data Exchange (ETDEWEB)

    Zupanič, Franc, E-mail: franc.zupanic@um.si [University of Maribor, Faculty of Mechanical Engineering, Smetanova ulica 17, SI-2000 Maribor (Slovenia); Markoli, Boštjan; Naglič, Iztok [University of Ljubljana, Faculty of Natural Sciences and Technologies, Askerceva 12, Ljubljana SI-1000 (Slovenia); Bončina, Tonica [University of Maribor, Faculty of Mechanical Engineering, Smetanova ulica 17, SI-2000 Maribor (Slovenia)

    2013-09-05

    Highlights: •We investigated the constitution of the Al-rich corner of the Al–Mn–Be system. •Be{sub 4}AlMn is a thermodynamically stable phase in the Al-corner of the Al–Mn–Be system. •The T-phase (Al{sub 15}Mn{sub 3}Be{sub 2}) is not a stable phase in the Al-corner at 600 °C. •The λ-Al{sub 4}Mn phase is a stable phase in the Al-corner at 600 °C. •T-phase is a stable phase at 750 °C. -- Abstract: This work investigated the constitution of the Al-rich corner within the ternary Al–Mn–Be phase diagram using SEM + EDS, AES, XRD and DSC. With respect to the results, an isothermal cross-section at 600 °C was established, as well as a prediction of the apparent liquidus projection in the Al-corner. Be{sub 4}AlMn is a thermodynamically stable phase in the Al-rich corner of the ternary phase diagram. The other ternary T-phase, usually designated as Al{sub 15}Mn{sub 3}Be{sub 2}, formed during solidification in alloys with Be:Mn atomic ratios of less than 4:1, and having more than 1.5 at.% Mn. This phase is not a stable phase in the Al-rich corner at 600 °C. In contrast, the λ-Al{sub 4}Mn phase is a stable one. The T-phase is stable over a rather large part of the phase diagram at least within a temperature range close to 750 °C, where it is in equilibrium with the Al-rich liquid phase, and Be{sub 4}AlMn.

  19. Some stable hydromagnetic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J L; Oberman, C R; Kulsrud, R M; Frieman, E A [Project Matterhorn, Princeton University, Princeton, NJ (United States)

    1958-07-01

    We have been able to find and investigate the properties of equilibria which are hydromagnetically stable. These equilibria can be obtained, for example, by wrapping conductors helically around the stellarator tube. Systems with I = 3 or 4 are indicated to be optimum for stability purposes. In some cases an admixture of I = 2 fields can be advantageous for achieving equilibrium. (author)

  20. An energy stable evolution method for simulating two-phase equilibria of multi-component fluids at constant moles, volume and temperature

    KAUST Repository

    Kou, Jisheng

    2016-02-25

    In this paper, we propose an energy-stable evolution method for the calculation of the phase equilibria under given volume, temperature, and moles (VT-flash). An evolution model for describing the dynamics of two-phase fluid system is based on Fick’s law of diffusion for multi-component fluids and the Peng-Robinson equation of state. The mobility is obtained from diffusion coefficients by relating the gradient of chemical potential to the gradient of molar density. The evolution equation for moles of each component is derived using the discretization of diffusion equations, while the volume evolution equation is constructed based on the mechanical mechanism and the Peng-Robinson equation of state. It is proven that the proposed evolution system can well model the VT-flash problem, and moreover, it possesses the property of total energy decay. By using the Euler time scheme to discretize this evolution system, we develop an energy stable algorithm with an adaptive choice strategy of time steps, which allows us to calculate the suitable time step size to guarantee the physical properties of moles and volumes, including positivity, maximum limits, and correct definition of the Helmhotz free energy function. The proposed evolution method is also proven to be energy-stable under the proposed time step choice. Numerical examples are tested to demonstrate efficiency and robustness of the proposed method.

  1. Effect of temperature on acid–base equilibria in separation techniques. A review

    International Nuclear Information System (INIS)

    Gagliardi, Leonardo G.; Tascon, Marcos; Castells, Cecilia B.

    2015-01-01

    Studies on the theoretical principles of acid–base equilibria are reviewed and the influence of temperature on secondary chemical equilibria within the context of separation techniques, in water and also in aqueous-organic solvent mixtures, is discussed. In order to define the relationships between the retention in liquid chromatography or the migration velocity in capillary electrophoresis and temperature, the main properties of acid–base equilibria have to be taken into account for both, the analytes and the conjugate pairs chosen to control the solution pH. The focus of this review is based on liquid–liquid extraction (LLE), liquid chromatography (LC) and capillary electrophoresis (CE), with emphasis on the use of temperature as a useful variable to modify selectivity on a predictable basis. Simplified models were evaluated to achieve practical optimizations involving pH and temperature (in LLE and CE) as well as solvent composition in reversed-phase LC. - Highlights: • The study of theoretical principles of acid–base equilibrium has been reviewed. • The proton transfer process is often present in the analytical separation practice. • The influence of temperature on secondary chemical equilibria is examined. • The focus is laid on liquid chromatography and capillary electrophoresis. • Temperature can be a useful variable to modify selectivity under predictable basis

  2. A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model

    KAUST Repository

    Kou, Jisheng; Sun, Shuyu

    2017-01-01

    Capillary pressure can significantly affect the phase properties and flow of liquid-gas fluids in porous media, and thus, the phase equilibrium calculation incorporating capillary pressure is crucial to simulate such problems accurately. Recently

  3. High-pressure anatectic paragneisses from the Namche Barwa, Eastern Himalayan Syntaxis: Textural evidence for partial melting, phase equilibria modeling and tectonic implications

    Science.gov (United States)

    Guilmette, C.; Indares, A.; Hébert, R.

    2011-05-01

    Rare kyanite-bearing anatectic paragneisses are found as boudins within sillimanite-bearing paragneisses of the core of the Namche Barwa Antiform, Tibet. In the present study, we document an occurrence from the NW side of the Yarlung Zangbo River. These rocks mainly consist of the assemblage garnet + K-feldspar + kyanite ± biotite + quartz + rutile ± plagioclase with kyanite locally pseudomorphed by sillimanite. The documented textures are consistent with the rocks having undergone biotite-dehydration melting in the kyanite stability field, under high-P granulite facies conditions, and having experienced melt extraction. However textures related to melt crystallization are ubiquitous both in polymineralic inclusions in garnet and in the matrix, suggesting that a melt fraction had remained in these rocks. Phase equilibria modelling was undertaken in the NCKFMASTHO system with THERMOCALC. P-T pseudosections built with the bulk compositions of one aluminous and one sub-aluminous paragneiss samples predict a biotite-kyanite-garnet-quartz-plagioclase-K-feldspar-liquid-rutile ± ilmenite field, in which biotite-dehydration melting occurs, located in the P-T range of ~ 800-875 °C and ~ 10-17 kbar. In addition, the topologies of these pseudosections are consistent with substantial melt loss during prograde metamorphism. A second set of P-T pseudosections with melt-reintegrated model bulk compositions were thus constructed to evaluate the effect of melt loss. The integration of textural information, precise mineral modes, mineral chemistry, and phase equilibria modelling allowed to constrain a P-T path where the rocks are buried to lower crustal depths at peak P-T conditions higher than 14 kbar and 825 °C, possibly in the order of 15-16 kbar and 850 °C, followed by decompression and cooling to P-T conditions of around 9 kbar and 810 °C, under which the remaining melt was solidified. The implications for granite production at the NBA and for Himalayan tectonic models

  4. Dissolved organic carbon enhances the mass transfer of hydrophobic organic compounds from Nonaqueous Phase Liquids (NAPLs) into the aqueous phase

    NARCIS (Netherlands)

    Smith, K.E.C.; Thullner, M.; Wick, L.Y.; Harms, H.

    2011-01-01

    The hypothesis that dissolved organic carbon (DOC) enhances the mass transfer of hydrophobic organic compounds from nonaqueous phase liquids (NAPLs) into the aqueous phase above that attributable to dissolved molecular diffusion alone was tested. In controlled experiments, mass transfer rates of

  5. Studies on the liquid-liquid phase distribution equilibria of selenium and its measurement in water using extraction plant with a pulsation column

    International Nuclear Information System (INIS)

    Iskanderani, F.; Sobhi, K.M.; Ejaz, M.

    1989-01-01

    Normal heptane, xylene and a 0.01 molar solution of 4-(5-nonyl)pyridine in toluene were investigated as extractants for selenium(IV) from nitric acid media in potassium iodide. Various parameters affecting the distribution of the element are investigated. Extraction at high aqueous to organic phase volume ratio was studied, using a liquid-liquid extraction plant with a pulsation column. The results were employed to measure selenium in spiked water samples. (author) 24 refs.; 8 figs

  6. Tube Radial Distribution Flow Separation in a Microchannel Using an Ionic Liquid Aqueous Two-Phase System Based on Phase Separation Multi-Phase Flow.

    Science.gov (United States)

    Nagatani, Kosuke; Shihata, Yoshinori; Matsushita, Takahiro; Tsukagoshi, Kazuhiko

    2016-01-01

    Ionic liquid aqueous two-phase systems were delivered into a capillary tube to achieve tube radial distribution flow (TRDF) or annular flow in a microspace. The phase diagram, viscosity of the phases, and TRDF image of the 1-butyl-3-methylimidazolium chloride and NaOH system were examined. The TRDF was formed with inner ionic liquid-rich and outer ionic liquid-poor phases in the capillary tube. The phase configuration was explained using the viscous dissipation principle. We also examined the distribution of rhodamine B in a three-branched microchannel on a microchip with ionic liquid aqueous two-phase systems for the first time.

  7. Studies of Redox Equilibria at Elevated Temperatures 2. An Automatic Divided-Function Autoclave and Cell with Flowing Liquid Junction for Electrochemical Measurements on Aqueous Systems.

    Energy Technology Data Exchange (ETDEWEB)

    Johnsson, Kerstin; Lewis, Derek; Pourbaix, Marian de

    1970-10-15

    An apparatus is described that has been developed for electrochemical studies of aqueous systems at temperatures above 100 deg C. It consists essentially of an electrically heated experimental cell enclosed by a separate pressure-vessel the walls of which are kept cool. This construction eliminates or reduces the problems of sealing electrical connections and of the corrosion of the pressure vessel, that commonly arise with conventional, externally-heated autoclaves. Pressure is applied to the cell by means of compressed air, diaphragm valves at the electrolyte outlet automatically maintaining the pressure in the cell about 1 atm lower than that in the pressure vessel. Two independent streams of electrolyte can be pumped into the experimental cell a special form of which has been developed in which may be formed a galvanic cell with a continuously regenerated flowing-liquid junction. In this form the apparatus enables experiments with, for example, one molal chloride solutions with pH 1-10, at temperatures up to about 250 deg C and under pressures up to about 40 atm. The apparatus has been tested in experiments in which classical measurements of the conductance of some aqueous electrolytes have been repeated. Good agreement with the earlier results has been obtained

  8. Phase equilibria, crystal structure and properties of complex oxides in the Nd{sub 2}O{sub 3}–SrO–CoO system

    Energy Technology Data Exchange (ETDEWEB)

    Aksenova, T.V.; Efimova, T.G. [Department of Physical and Inorganic Chemistry, Institute of Natural Science and Mathematics, Ural Federal University, Lenin av., 51, Yekaterinburg 620000 (Russian Federation); Lebedev, O.I. [Laboratoire CRISMAT, ENSICAEN UMR6508, 6 Bd Maréchal Juin, Cedex 4, Caen 14050 (France); Elkalashy, Sh.I.; Urusova, A.S. [Department of Physical and Inorganic Chemistry, Institute of Natural Science and Mathematics, Ural Federal University, Lenin av., 51, Yekaterinburg 620000 (Russian Federation); Cherepanov, V.A., E-mail: v.a.cherepanov@urfu.ru [Department of Physical and Inorganic Chemistry, Institute of Natural Science and Mathematics, Ural Federal University, Lenin av., 51, Yekaterinburg 620000 (Russian Federation)

    2017-04-15

    The phase equilibria in the ½Nd{sub 2}O{sub 3}–SrO–CoO system were systematically studied at 1373 K in air. The intermediate phases formed in the ½Nd{sub 2}O{sub 3}–SrO–CoO system at 1373 K in air are: Nd{sub 1-x}Sr{sub x}CoO{sub 3-δ} (0.0≤x≤0.5 with orthorhombic structure, sp. gr. Pbnm and 0.6≤x≤0.95 whose structure was detected as cubic according to XRD sp. gr. Pm3m, but shown to be tetragonal by TEM due to the oxygen vacancy ordering), Nd{sub 2-y}Sr{sub y}CoO{sub 4-δ} (0.6≤y≤1.1 with tetragonal K{sub 2}NiF{sub 4}-type structure, sp. gr. I4/mmm) and Nd{sub 2-z}Sr{sub z}O{sub 3} (0.0≤z≤0.15 with hexagonal structure, sp. gr. P-3m1). The unit cell parameters for the single phase samples were refined by the Rietveld analysis. The changes of oxygen content in Nd{sub 1-x}Sr{sub x}CoO{sub 3-δ} (0.6≤x≤0.95) and Ruddlesden-Popper oxide Nd{sub 2-y}Sr{sub y}CoO{sub 4-δ} were examined by TGA. All were found to be oxygen deficient phases. High-temperature dilatometry allows calculating the thermal expansion coefficient and evaluating the chemical expansion coefficient at high temperature. The projection of isothermal-isobaric phase diagram for the Nd–Sr–Co–O system at 1373 K in air to the compositional triangle of metallic components has been constructed. The phase equilibria in the studied Nd–Sr–Co–O system were compared to La–Sr–Co–O and Nd–M–Co–O (M=Ca and Ba). - Graphical abstract: Crystal structure of vacancy ordered supercell for Nd{sub 0.2}Sr{sub 0.8}CoO{sub 3-δ} and projection of phase diagram for the Nd–Sr–Co–O system onto the triangle edge of metallic components at 1373 K in air. - Highlights: • The diagram for the Nd–Sr–Co–O system at 1373 K in air has been constructed. • The crystal structure of Nd{sub 1-x}Sr{sub x}CoO{sub 3-δ} and Nd{sub 2-y}Sr{sub y}CoO{sub 4±δ} was refined. • The formation of superstructure due to the oxygen vacancy ordering was proved. • The changes of oxygen

  9. Extraction Equilibrium of Acrylic Acid by Aqueous Two-Phase Systems Using Hydrophilic Ionic Liquids

    International Nuclear Information System (INIS)

    Lee, Yong Hwa; Lee, Woo Youn; Kim, Ki-Sub; Hong, Yeon Ki

    2014-01-01

    As an effective method for extraction of acrylic acid, aqueous two-phase systems based on morpholinium ionic liquids were used in this study. Effects of the alkyl chain length of cation in morpholinium ionic liquids on phase diagram and extraction efficiencies were investigated. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of morpholinium ionic liquids to aqueous K 2 HPO 4 solutions. It can be found that the ability of morpholinium ionic liquids for phase separation followed the order [HMMor][Br]>[OMMor][Br]>[BMMor][Br]>[EMMor][Br]. There was little difference between binodal curves of imidazolium ionic liquids and those of morpholinium ionic liquids. 50-90% of the extraction efficiency was observed for acrylic acid by aqueous two phase extraction of acrylic acid with morpholinium ionic liquids. It can be concluded that morpholinium ionic liquids/K 2 HPO 4 were effective for aqueous two phases extraction of acrylic acid comparing to imidazolium ionic liquids/K 2 HPO 4 systems because of their lower cost

  10. Synergistic extraction of transition metal cations from aqueous media by two separated organic phases

    International Nuclear Information System (INIS)

    Goldberg, I.

    1991-12-01

    We have therefore initiated novel approaches to the study of the mechanism of the synergistic extraction of metal ions by means of two separated organic phases, which are brought in contact with the same aqueous phase. The present work is concerned with the extraction of transition metals and actinides ions from nitric acid by chelating agents e.g., HTTA thenoyltrifluoroacetone in a diluent - the first organic phase, and by natural donor, e.g., TBP, tri-butyl phosphate in a diluent the second organic phase. The adduct formation was studied by means of spectrochemical and radiochemical methods. In the first approach the aqueous phase was attacked with both organic phases simultanously (the static or parallel extraction). In this method organic phase are separated one from the other. It was shown that even in the absence of mixing, synergism is observed under this experimental conditions. The results indicate, that adduct formation occurs in both organic phases. Nevertheless the enhanchment of extraction in the TBP phase is by far greater than that in the HTTA containing phase. This approach has one disadvatage, viz., the experiments are very time consuming, a typical experiment requiring over 10 days. In order to overcome this difficulty, the following experiments were carried out: the aqueous phase were first shaken with diluent containing an anionic ligand and the phases were allowed to separate. Then the aqueous solution were shaken with diluent containing a netural donor and the phase again were allowed to separate. The concentration of the metal ions in all the phases were determined. The experiments were repeated with an other diluent replacing the first diluent in one or both organic phases. In this way eight sequences of experiments were carried out for each concentration set chosen. The results thus point out that this experimental approach open new possibilities to investigate the mechanism and the kinetics of synergistic extraction processes. (author) the

  11. A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model

    KAUST Repository

    Kou, Jisheng

    2017-09-30

    Capillary pressure can significantly affect the phase properties and flow of liquid-gas fluids in porous media, and thus, the phase equilibrium calculation incorporating capillary pressure is crucial to simulate such problems accurately. Recently, the phase equilibrium calculation at specified moles, volume and temperature (NVT-flash) becomes an attractive issue. In this paper, capillarity is incorporated into the phase equilibrium calculation at specified moles, volume and temperature. A dynamical model for such problem is developed for the first time by using the laws of thermodynamics and Onsager\\'s reciprocal principle. This model consists of the evolutionary equations for moles and volume, and it can characterize the evolutionary process from a non-equilibrium state to an equilibrium state in the presence of capillarity effect at specified moles, volume and temperature. The phase equilibrium equations are naturally derived. To simulate the proposed dynamical model efficiently, we adopt the convex-concave splitting of the total Helmholtz energy, and propose a thermodynamically stable numerical algorithm, which is proved to preserve the second law of thermodynamics at the discrete level. Using the thermodynamical relations, we derive a phase stability condition with capillarity effect at specified moles, volume and temperature. Moreover, we propose a stable numerical algorithm for the phase stability testing, which can provide the feasible initial conditions. The performance of the proposed methods in predicting phase properties under capillarity effect is demonstrated on various cases of pure substance and mixture systems.

  12. Experimental determination of the isothermal (vapour + liquid) equilibria of binary aqueous solutions of sec-butylamine and cyclohexylamine at several temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Chiali-Baba Ahmed, Nouria [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, Post Office Box 119, Tlemcen 13000 (Algeria); Negadi, Latifa, E-mail: latifanegadi@yahoo.fr [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, Post Office Box 119, Tlemcen 13000 (Algeria); Mokbel, Ilham [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5280, Universite Claude Bernard - Lyon I, 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France); Kaci, Ahmed Ait [Laboratoire de Thermodynamique et Modelisation Moleculaire, Universite des Sciences et de la Technologie Houari Boumediene, Post Office Box 32, El Alia 16111, Bab Ezzouar (Algeria); Jose, Jacques [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5280, Universite Claude Bernard - Lyon I, 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France)

    2012-01-15

    Highlights: > Vapour pressures of sec-butylamine or cyclohexylamine and their aqueous solutions. > The investigated temperatures are 273 K and 363 K. > The (cyclohexylamine + water) mixture shows positive azeotropic behaviour. > The (sec-butylamine + water) or (cyclohexylamine + water) exhibit positive G{sup E}. - Abstract: The vapour pressures of (sec-butylamine + water), (cyclohexylamine + water) binary mixtures, and of pure sec-butylamine and cyclohexylamine components were measured by means of two static devices at temperatures between 293 (or 273) K and 363 K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (G{sup E}) were calculated for several constant temperatures and fitted to a fourth-order Redlich-Kister equation using the Barker's method. The (cyclohexylamine + water) system shows positive azeotropic behaviour for all investigated temperatures. The two binary mixtures exhibit positive deviations in G{sup E} for all investigated temperatures over the whole composition range.

  13. Extraction of peptide tagged cutinase in detergent-based aqueous two-phase systems

    NARCIS (Netherlands)

    Rodenbrock, A.; Selber, K.; Egmond, M.R.; Kula, M.-R.

    2010-01-01

    Detergent-based aqueous two-phase systems have the advantage to require only one auxiliary chemical to induce phase separation above the cloud point. In a systematic study the efficiency of tryptophan-rich peptide tags was investigated to enhance the partitioning of an enzyme to the detergent-rich

  14. Differentiation of surface properties of chlorococcalean algae by means of aqueous two phase systems

    Directory of Open Access Journals (Sweden)

    Jan Burczyk

    2014-01-01

    Full Text Available Algal cells belonging to various strains of Chlorococcales (Chlorophyta have been partitioned in aqueous two-phase systems containing ionogenic polymers, DEAE-dextran or SDS-dextran, at various pH values. Strain-specific differences of partition type which have been found in the phase systems used can be useful for distinguishing of algal cells.

  15. A review of catalytic aqueous-phase reforming of oxygenated hydrocarbons derived from biorefinery water fractions

    NARCIS (Netherlands)

    Coronado, I.; Stekrova, M.; Reinikainen, M.; Simell, P.; Lefferts, Leonardus; Lehtonen, J.

    2016-01-01

    Aqueous-phase reforming (APR) of oxygenated hydrocarbons is a process for the production of hydrogen and light alkanes. The reactants of APR remain in liquid phase during the reaction avoiding an energetically demanding vaporization-step compared to processes such as steam reforming (SR).

  16. Propene Hydroformylation by Supported Aqueous-phase Rh-NORBOS Catalysts

    DEFF Research Database (Denmark)

    Riisager, Anders; Eriksen, Kim Michael; Hjortkjær, Jes

    2003-01-01

    The gas-phase hydroformylation reaction of propene using supported aqueous-phase (SAP) Rh-NORBOS modified catalysts in a continuous flow reactor has been examined. SAP catalysts supported on six different support materials were made by wet impregnation using solutions of the precursor complex Rh(...

  17. Phase equilibria of microemulsion forming system n-decyl-(beta)-D-glucopyranoside/water/n-octane/1-butanol

    DEFF Research Database (Denmark)

    Kahl, Heike; Quitzsch, Konrad; Stenby, Erling Halfdan

    1997-01-01

    of multicomponent system is the coexistence of a highly structural liquid phase enriched with amphiphilic compounds and an excess water or an excess oil phase or both of them. The phase behaviour was studied experimentally by use of turbidity titration and HPLC measurements and theoretically by application...... of the UNIQUAC-equation and the UNIFAC-method. The UNIFAC-method is able to describe the phase behaviour in the quaternary system qualitatively, without fitting parameters. However, by applying the UNIQUAC-method, with adjustable parameters, it was only possible to model the ternary subsystems. The modelling......A systematic investigation of the phase behaviour involving microemulsions is presented with respect to experimental and calculated data for the four-component system n-decyl-(beta)-D-glucopyranoside/water/n-octane/1-butanol and its corresponding ternaries at 25°C. The main feature of this kind...

  18. Phase equilibria in the KFeS2-Fe-S system at 300-600 °C and bartonite stability

    Science.gov (United States)

    Osadchii, Valentin O.; Voronin, Mikhail V.; Baranov, Alexander V.

    2018-05-01

    The article deals with phase relations in the KFeS2-Fe-S system studied by the dry synthesis method in the range of 300-600 °C and at a pressure of 1 bar. At the temperature below 513 ± 3 °C, pyrite coexists with rasvumite and there are pyrite-rasvumite-KFeS2 and pyrite-rasvumite-pyrrhotite equilibria established. Above 513 ± 3 °C pyrite and rasvumite react to form KFeS2 and pyrrhotite, limiting the pyrite-rasvumite association to temperatures below this in nature. The experiments also outline the compositional stability range of the copper-free analog of murunskite (K x Fe2- y S2) and suggest that mineral called bartonite is not stable in the Cl-free system, at least at atmospheric pressure and the temperature in the experiments. Chlorbartonite could be easily produced after adding KCl in the experiment. Possible parageneses in the quaternary K-Fe-S-Cl system were described based on the data obtained in this research and found in the previous studies. The factors affecting the formation of potassium-iron sulfides in nature were discussed.

  19. Learning efficient correlated equilibria

    KAUST Repository

    Borowski, Holly P.; Marden, Jason R.; Shamma, Jeff S.

    2014-01-01

    The majority of distributed learning literature focuses on convergence to Nash equilibria. Correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However, there are no existing distributed learning algorithms that converge to specific correlated equilibria. In this paper, we provide one such algorithm which guarantees that the agents' collective joint strategy will constitute an efficient correlated equilibrium with high probability. The key to attaining efficient correlated behavior through distributed learning involves incorporating a common random signal into the learning environment.

  20. Learning efficient correlated equilibria

    KAUST Repository

    Borowski, Holly P.

    2014-12-15

    The majority of distributed learning literature focuses on convergence to Nash equilibria. Correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However, there are no existing distributed learning algorithms that converge to specific correlated equilibria. In this paper, we provide one such algorithm which guarantees that the agents\\' collective joint strategy will constitute an efficient correlated equilibrium with high probability. The key to attaining efficient correlated behavior through distributed learning involves incorporating a common random signal into the learning environment.

  1. Phase equilibria in the Cs-U-O system in the temperature range from 873 to 1273 K

    International Nuclear Information System (INIS)

    Fee, D.C.; Johnson, C.E.

    1978-01-01

    Portions of the cesium-uranium-oxygen system have been investigated between 873 and 1273 K and a phase diagram has been constructed using these data and the data of other workers in the field. A consistent set of measured and estimated thermodynamic data for cesium uranates has been used to calculate the equilibrium cesium partial pressure and the equilibrium oxygen partial pressure over two and three phase regions in the Cs-U-O system. For a given temperature, the equilibrium cesium partial pressure in a two phase region decreases as the equilibrium oxygen partial pressure increases. (author)

  2. Experimental Investigation of Phase Equilibria in the Ho-Ti-Si Ternary System at 973 K (700 °C)

    Science.gov (United States)

    Han, Feng; Zhan, Yongzhong

    2018-02-01

    Phase equilibrium relations of the Ho-Ti-Si ternary system at 973 K (700 °C) were experimentally researched by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometer (EDS). The isothermal section of the system at 973 K (700 °C) consists of 14 three-phase regions, 27 two-phase regions, and 14 single-phase regions. The phases Ti5Si3, Ti5Si4, TiSi, TiSi2, Ho5Si3, Ho5Si4, HoSi, αHoSi2-b, and βHoSi2-a are proved to exist at 973 K (700 °C). Previously reported HoTiSi and Ho2Ti3Si4 ternary compounds were confirmed to exist at this temperature. The solubility of Ho in the intermediate phases (i.e., TiSi2, TiSi, Ti5Si4, and Ti5Si3) at the Ti-Si side is extremely small. The maximum solubilities of Ti in HoSi2-b, Ho5Si4, and Ho5Si3 are confirmed to be 8.0, 7.2, and 6.0 at. pct, respectively.

  3. Free energy and phase equilibria for the restricted primitive model of ionic fluids from Monte Carlo simulations

    International Nuclear Information System (INIS)

    Orkoulas, G.; Panagiotopoulos, A.Z.

    1994-01-01

    In this work, we investigate the liquid--vapor phase transition of the restricted primitive model of ionic fluids. We show that at the low temperatures where the phase transition occurs, the system cannot be studied by conventional molecular simulation methods because convergence to equilibrium is slow. To accelerate convergence, we propose cluster Monte Carlo moves capable of moving more than one particle at a time. We then address the issue of charged particle transfers in grand canonical and Gibbs ensemble Monte Carlo simulations, for which we propose a biased particle insertion/destruction scheme capable of sampling short interparticle distances. We compute the chemical potential for the restricted primitive model as a function of temperature and density from grand canonical Monte Carlo simulations and the phase envelope from Gibbs Monte Carlo simulations. Our calculated phase coexistence curve is in agreement with recent results of Caillol obtained on the four-dimensional hypersphere and our own earlier Gibbs ensemble simulations with single-ion transfers, with the exception of the critical temperature, which is lower in the current calculations. Our best estimates for the critical parameters are T * c =0.053, ρ * c =0.025. We conclude with possible future applications of the biased techniques developed here for phase equilibrium calculations for ionic fluids

  4. Thermal analysis and prediction of phase equilibria in the TiO2-Bi2O3 system

    International Nuclear Information System (INIS)

    Lopez-Martinez, Jaqueline; Romero-Serrano, Antonio; Hernandez-Ramirez, Aurelio; Zeifert, Beatriz; Gomez-Yanez, Carlos; Martinez-Sanchez, Roberto

    2011-01-01

    A thermodynamic study on the TiO 2 -Bi 2 O 3 system was carried out using differential thermal analysis (DTA) and X-Ray diffraction (XRD) techniques covering the composition range from 65 to 90 mol% Bi 2 O 3 . From the XRD results the only two intermediate compounds in the Bi 2 O 3 rich region were Bi 4 Ti 3 O 12 and Bi 12 TiO 20 . The Bi 4 Ti 3 O 12 phase presents the well known plate-like morphology. The experimentally determined phase transition temperatures with DTA technique were compared with thermodynamic calculated results and good agreement was obtained. The DTA results also showed that the limit of the peritectic reaction between liquid and Bi 4 Ti 3 O 12 occurs approximately at 90 mol% Bi 2 O 3 . The phase diagram of the TiO 2 -Bi 2 O 3 system was calculated using a quasichemical model for the liquid phase. The thermodynamic properties of the intermediate compounds were estimated from the data of TiO 2 and Bi 2 O 3 pure solids. In this manner, data for this binary system have been analysed and represented with a small adjustable parameter for the liquid phase.

  5. Subcritical hydrothermal liquefaction of barley straw in fresh water and recycled aqueous phase

    DEFF Research Database (Denmark)

    Zhu, Zhe; Toor, Saqib; Rosendahl, Lasse

    2014-01-01

    This project focuses on the investigation of addition of aqueous phase in the production of biofuel from biomass through hydrothermal liquefaction (HTL) technology. Hydrothermal liquefaction is a wet thermal conversion process, which can convert all kinds of biomass to fuels. In this study, barley...... straw was first liquefied in fresh distilled water with the presence of K2CO3 catalyst at 300 C as the reference run. Afterwards, the aqueous phase which is obtained from liquefaction process in the previous run was recycled and used as the reaction medium from the second to the fourth run....... With the addition of recycling aqueous phase in HTL process, it is expected that the amount of the waste water and energy consumption can be reduced. The effect of water recirculation on product yield and properties was investigated in this study. The results showed that bio-oil yield was 34.85 wt% when the barley...

  6. Fluid phase equilibria of the reaction mixture during the selective hydrogenation of 2-butenal in dense carbon dioxide

    DEFF Research Database (Denmark)

    Musko, Nikolai; Jensen, Anker Degn; Baiker, Alfons

    2012-01-01

    Knowledge of the phase behaviour and composition is of paramount importance for understanding multiphase reactions. We have investigated the effect of the phase behaviour in the palladium-catalysed selective hydrogenation of 2-butenal to saturated butanal in dense carbon dioxide. The reactions were...... cell. The results of the catalytic experiments showed that small amounts of carbon dioxide added to the system significantly decrease the conversion, whereas at higher loadings of CO2 the reaction rate gradually increases reaching a maximum. The CPA calculations revealed that this maximum is achieved...... performed using a 5wt% Pd on activated carbon in custom-designed high pressure autoclaves at 323K. The Cubic-Plus-Association (CPA) equation of state was employed to model the phase behaviour of the experimentally studied systems. CPA binary interaction parameters were estimated based on the experimental...

  7. Phase equilibria in the CdMoO4-Gd2(MoO4)3 system

    International Nuclear Information System (INIS)

    Tunik, T.A.; Fedorov, N.F.; Razumovskij, S.N.

    1980-01-01

    The constitutional diagram of the CdMoO 4 -Cd 2 (MoO 4 ) 3 system has been plotted using statistical and dynamic methods as well as a complex of instrumental analysis procedures. Three major phases have been found to occur in the systems, viz.: CdMoO 4 based solid solutions that crystallize in the range from 0 to 25 mol.percent of Cd 2 (MoO 4 ) 3 and pass in transit the two-phase narrow region becoming then solid solutions having a distorted scheelite structure and existing in concentrations from 40 to 65 mol.% of Cd 2 (MoO 4 ) 3 . The entire range, in which the Cd 2 (MoO 4 ) 3 solid solutions can exist, amounts to less than 5 mol.%. Certain crystallochemical constants of the phases that occur in the system have been determined [ru

  8. Hydrothermal upgrading of algae paste: Inorganics and recycling potential in the aqueous phase

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Bhavish; Guo, Miao; Chong, Chinglih; Sarudin, Syazwani Hj Mat; Hellgardt, Klaus, E-mail: k.hellgardt@imperial.ac.uk

    2016-10-15

    Hydrothermal Liquefaction (HTL) for algal biomass conversion is a promising technology capable of producing high yields of biocrude as well as partitioning even higher quantity of nutrients in the aqueous phase. To assess the feasibility of utilizing the aqueous phase, HTL of Nannochloropsis sp. was carried out in the temperature range of 275 to 350 °C and Residence Times (RT) ranging between 5 and 60 min The effect of reaction conditions on the NO{sub 3}{sup −} , PO{sub 4}{sup 3} {sup −}, SO{sub 4}{sup 2} {sup −}, Cl{sup −}, Na{sup +}, and K{sup +} ions as well as Chemical Oxygen Demand (COD) and pH was investigated with view of recycling the aqueous phase for either cultivation or energy generation via Anaerobic Digestion (AD), quantified via Lifecycle Assessment (LCA). It addition to substantial nutrient partitioning at short RT, an increase in alkalinity to almost pH 10 and decrease in COD at longer RT was observed. The LCA investigation found reaction conditions of 275 °C/30 min and 350 °C/10 min to be most suitable for nutrient and energy recovery but both processing routes offer environmental benefit at all reaction conditions, however recycling for cultivation has marginally better environmental credentials compared to AD. - Highlights: • HTL of algal biomass and nutrient reclamation • Microalgae HTL aqueous phase inorganics analysis • Recycle/re-use of aqueous phase for energy or cultivation • Substantial environmental benefit from HTL of aqueous phase • Reuse for cultivation more beneficial than Anaerobic Digestion.

  9. Critical phenomena in binary fluid mixtures : Classification of phase equilibria with the simplified-perturbed-hard-chain theory

    NARCIS (Netherlands)

    Van Pelt, A.

    1992-01-01

    I. INTRODUCTION AND THEORY This PhD research is mainly concerned with the global phase behaviour, that is calculated from the Simplified-Perturbed-Hard-Chain equation. This equation distinguishes itself from many other equations of state by a sound theoretical background. We enter the field of the

  10. Liquid-liquid phase equilibria for ternary systems of several polyethers with NaCl and H2O

    NARCIS (Netherlands)

    Milosevic, M.; Staal, K.J.J.; Schuur, Boelo; de Haan, A.B.

    2014-01-01

    Liquid–liquid extraction using polymers followed by induced phase separation is a potential energy reducing technology for water–salt separation. Ternary equilibrium data have been determined and reported for the (block co)poly ethers–sodium chloride–water systems at two different temperatures at

  11. Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure%Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure

    Institute of Scientific and Technical Information of China (English)

    王琳; 曹丰璞; 刘珊珊; 杨浩

    2011-01-01

    High-pressure vapor-liquid phase equilibrium data for carbon dioxide+ isopentanol were measured at tempera- tures of 313.2, 323.1, 333.5 and 343.4 K in the pressure range of 4.64 to 12.71 MPa in a variable-volume high-pressure visual cell. The experimental data were well correlated with Peng-Robinson equation of state (PR-EOS) together with van der Waals-2 two-parameter mixing rule, and the binary interaction parameters were obtained. Henry coefficients and partial molar volumes of CO2 at infinite dilution were estimated based on Krichevsky-Kasarnovsky equation, and Henry coefficients increase with increasing temperature, however, partial molar volumes of CO2 at infinite dilution are negative and the magnitudes decrease with temperature.

  12. Effect of Secondary Equilibria on the Adsorption of Ibuprofen Enantiomers on a Chiral Stationary Phase with a Grafted Antibiotic Eremomycin

    Science.gov (United States)

    Reshetova, E. N.; Asnin, L. D.; Kachmarsky, K.

    2018-02-01

    The chromatographic separation of ibuprofen enantiomers on a Nautilus-E chiral stationary phase with a grafted eremomycin antibiotic at high column loading is accompanied by distortion of the shape of chromatographic peaks. A model is proposed to explain this phenomenon. A number of factors are considered in the model: the ionization of ibuprofen in the mobile phase, the pH change in the mass transfer zone caused by ionization, and competitive adsorption involving buffer components. Simulations performed using this model within the theory of nonequilibrium chromatography allow the shape of chromatograms for large amounts of S- and R-ibuprofen samples to be predicted. The adsorption mechanism is found to be mainly ion-exchange. The contribution from the molecular adsorption of ibuprofen to the total retention is shown to be several percent.

  13. Role of Acid–Base Equilibria in the Size, Shape, and Phase Control of Cesium Lead Bromide Nanocrystals

    Science.gov (United States)

    2018-01-01

    A binary ligand system composed of aliphatic carboxylic acids and primary amines of various chain lengths is commonly employed in diverse synthesis methods for CsPbBr3 nanocrystals (NCs). In this work, we have carried out a systematic study examining how the concentration of ligands (oleylamine and oleic acid) and the resulting acidity (or basicity) affects the hot-injection synthesis of CsPbBr3 NCs. We devise a general synthesis scheme for cesium lead bromide NCs which allows control over size, size distribution, shape, and phase (CsPbBr3 or Cs4PbBr6) by combining key insights on the acid–base interactions that rule this ligand system. Furthermore, our findings shed light upon the solubility of PbBr2 in this binary ligand system, and plausible mechanisms are suggested in order to understand the ligand-mediated phase control and structural stability of CsPbBr3 NCs. PMID:29381326

  14. Violent flows in aqueous foams III: physical multi-phase model comparison with aqueous foam shock tube experiments

    Science.gov (United States)

    Redford, J. A.; Ghidaglia, J.-M.; Faure, S.

    2018-06-01

    Mitigation of blast waves in aqueous foams is a problem that has a strong dependence on multi-phase effects. Here, a simplified model is developed from the previous articles treating violent flows (D'Alesio et al. in Eur J Mech B Fluids 54:105-124, 2015; Faure and Ghidaglia in Eur J Mech B Fluids 30:341-359, 2011) to capture the essential phenomena. The key is to have two fluids with separate velocities to represent the liquid and gas phases. This allows for the interaction between the two phases, which may include terms for drag, heat transfer, mass transfer due to phase change, added mass effects, to be included explicitly in the model. A good test for the proposed model is provided by two experimental data sets that use a specially designed shock tube. The first experiment has a test section filled with spray droplets, and the second has a range of aqueous foams in the test section. A substantial attenuation of the shock wave is seen in both cases, but a large difference is observed in the sound speeds. The droplets cause no observable change from the air sound speed, while the foams have a reduced sound speed of approximately 50-75 m/s . In the model given here, an added mass term is introduced in the governing equations to capture the low sound speed. The match between simulation and experiment is found to be satisfactory for both droplets and the foam. This is especially good when considering the complexity of the physics and the effects that are unaccounted for, such as three-dimensionality and droplet atomisation. The resulting statistics illuminate the processes occurring in such flows.

  15. Recovery of Picloram and 2,4-Dichlorophenoxyacetic Acid from Aqueous Samples by Reversed-Phase Solid-Phase Extraction

    Science.gov (United States)

    Martha J.M. Wells; Jerry L. Michael

    1987-01-01

    Extensive preparation of samples before chromatographic analysis is usually the most time-consuming process in the determination of many organic compounds in environmental matrices. In the past, removal of some organic from aqueous solution was commonly done by liquid/liquid extraction. However, the introduction of stable, covalently bonded reversed-phase sorbents now...

  16. Ternary equilibria in bismuth--indium--lead alloys

    International Nuclear Information System (INIS)

    Liao, K.C.; Johnson, D.L.; Nelson, R.C.

    1975-01-01

    The liquidus surface is characterized by three binary equilibria. One binary extends from the Pb--Bi peritectic to the Pb--In peritectic. The other two extend from In--Bi eutectics, merge at 50 at. percent Bi and 30 at. percent Pb, and end at the Bi--Pb eutectic. Based on analysis of ternary liquidus contours and vertical sections, it is suggested that solidification for high lead and very high indium alloys occurs from two-phase equilibria. Solidification from all other alloys occurs from three-phase equilibria. Four-phase solidification does not occur in this system

  17. Comparison of two association models (Elliott-Suresh-Donohue and simplified PC-SAFT) for complex phase equilibria of hydrocarbon-water and amine-containing mixtures

    DEFF Research Database (Denmark)

    Grenner, Andreas; Schmelzer, Jürgen; von Solms, Nicolas

    2006-01-01

    , and water. Furthermore, the predictive capabilities of the models are investigated for four ternary systems composed of these components, which exhibit complex liquid-liquid(-liquid) equilibria (LLLE). Various aspects of association models which have an influence in the results are studied for the PC......, both models perform overall similarly for the binary systems, although ESD shows a remarkably good behavior despite its simplicity and the use of only the two-site scheme for all associating compounds. The prediction of the LLE in the ternary systems water + octane + aniline and water + CHA + aniline......Two Wertheim-based association models, the simplified PC-SAFT and the Elliott-Suresh-Donohue (ESD) equation of state, are compared in this work for the description of vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) in binary systems of aniline, cyclohexylamine (CHA), hydrocarbons...

  18. Phase equilibria of toluene/heptane with deep eutectic solvents based on ethyltriphenylphosphonium iodide for the potential use in the separation of aromatics from naphtha

    International Nuclear Information System (INIS)

    Kareem, Mukhtar A.; Mjalli, Farouq S.; Hashim, Mohd Ali; Hadj-Kali, Mohamed K.O.; Ghareh Bagh, Fatemeh Saadat; Alnashef, Inas M.

    2013-01-01

    Highlights: • Ionic liquid analogues are introduced as potential replacements for ionic liquids. • Deep eutectic solvents presented in this work were successful for extracting aromatics. • Hand correlation was applied to ascertain the experimental measurements. • The NRTL thermodynamic model was capable for correlating the LLE experimental data. -- Abstract: In this work, the liquid–liquid extraction of toluene from hydrocarbons mixtures (toluene/heptane) was investigated using deep eutectic solvents as solvents. Ethyltriphenylphosphonium iodide as a salt with either ethylene glycol or sulfolane as hydrogen-bond donors (HBDs) were utilized for synthesizing six DESs. (Liquid + liquid) equilibria data were determined experimentally for the ternary system (toluene + heptane + DES) at (30, 40, 50, and 60) °C and atmospheric pressure. Hand correlation was applied to establish the reliability of the experimental data. In many cases the correlation factor is found close to unity which indicates high reliability of the data. The selectivities and distribution coefficients were used to determine the suitability of these DESs as solvents for this extraction process. Higher selectivities than those published for sulfolane as a commercial solvent were observed. The DES made from ethyltriphenylphosphonium iodide and sulfolane at salt:HBD of 1:4 showed the best separation capability at 30 °C. Thus, it was further characterized by measuring its viscosity and refractive index at a range of temperatures to help understand its physical behaviour needed for process design. The non-random two-liquid (NRTL) model was applied successfully to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It has been found that the third non-randomness parameter varies linearly with the HBD number of moles

  19. Calculation of phase equilibria in Ti-Al-Cr-Mn quaternary system for developing lower cost titanium alloys

    International Nuclear Information System (INIS)

    Lu, X.G.; Li, C.H.; Chen, L.Y.; Qiu, A.T.; Ding, W.Z.

    2011-01-01

    Highlights: → This paper is about the concept of designing the lower cost titanium alloy. → The thermodynamic database of Ti-Al-Cr-Mn system is built up by Calphad method. → The pseudobinary sections with Cr: Mn = 3:1 and Al = 3, 4.5 and 6.0 wt% are calculated. → This may provide the theoretical support for designing the lower cost titanium alloy. - Abstract: The Ti-Al-Cr-Mn system is a potentially useful system for lower cost titanium alloy development; however, there are few reports about the experimental phase diagrams and the thermodynamical assessment for this system. In this study, the previous investigations for the thermodynamic descriptions of the sub-systems in the Ti-Al-Cr-Mn system are reviewed, our previous assessment for the related sub-systems in this quaternary system is summarized, the thermodynamical database of this quaternary system is built up by directly extrapolating from all sub-systems assessed by means of the Calphad method, then the pseudobinary sections with Cr:Mn = 3:1 and Al = 0.0, 3.0, 4.5 and 6.0 wt% are calculated, respectively. These pseudobinary phase diagrams may provide the theoretical support for designing the lower cost titanium alloys with different microstructures (α, α + β, and β titanium alloy).

  20. (Liquid + liquid) equilibria of aqueous solutions of butyric acid with n-heptane and toluene at T = (298.2, 308.2, and 318.2) K

    International Nuclear Information System (INIS)

    Ghanadzadeh Gilani, H.; Ghanadzadeh Gilani, A.; Janbaz, M.

    2013-01-01

    Highlights: ► Liquid equilibrium data of (water + butyric acid + n-heptane) were obtained. ► LLE data were correlated with NRTL and UNIQUAC models. ► Distribution coefficients and separation factors were evaluated. - Abstract: Solubility and tie line data for the (water + butyric acid + n-heptane) and (water + butyric acid + toluene) ternary systems were determined at T = (298.2, 308.2, and 318.2) K and atmospheric pressure. Solubility data were obtained by the cloud-point titration method. The concentration of each phase was determined by acidimetric titration, the Karl-Fischer technique, and refractive index measurements. The experimental tie-line data were correlated using the UNIQUAC and NRTL thermodynamic models. The reliability of the experimental data was determined through the Othmer–Tobias and Hand plots. Distribution coefficients and separation factors were evaluated for each system over the immiscibility regions.

  1. PHASE BEHAVIOR OF LIGHT GASES IN HYDROCARBON AND AQUEOUS SOLVENTS

    Energy Technology Data Exchange (ETDEWEB)

    KHALED A.M. GASEM; ROBERT L. ROBINSON, JR.

    1998-08-31

    Under previous support from the Department of Energy, an experimental facility has been established and operated to measure valuable vapor-liquid equilibrium data for systems of interest in the production and processing of coal fluids. To facilitate the development and testing of models for prediction of the phase behavior for such systems, we have acquired substantial amounts of data on the equilibrium phase compositions for binary mixtures of heavy hydrocarbon solvents with a variety of supercritical solutes, including hydrogen, methane, ethane, carbon monoxide, and carbon dioxide. The present project focuses on measuring the phase behavior of light gases and water in Fischer-Tropsch (F-T) type solvents at conditions encountered in indirect liquefaction processes and evaluating and developing theoretically-based correlating frameworks to predict the phase behavior of such systems. Specific goals of the proposed work include (a) developing a state-of-the-art experimental facility to permit highly accurate measurements of equilibrium phase compositions (solubilities) of challenging F-T systems, (b) measuring these properties for systematically-selected binary, ternary and molten F-T wax mixtures to provide critically needed input data for correlation development, (c) developing and testing models suitable for describing the phase behavior of such mixtures, and (d) presenting the modeling results in generalized, practical formats suitable for use in process engineering calculations. During the present period, the Park-Gasem-Robinson (PGR) equation of state (EOS) has been modified to improve its volumetric and equilibrium predictions. Specifically, the attractive term of the PGR equation was modified to enhance the flexibility of the model, and a new expression was developed for the temperature dependence of the attractive term in this segment-segment interaction model. The predictive capability of the modified PGR EOS for vapor pressure, and saturated liquid and

  2. Phase-equilibria for design of coal-gasification processes: dew points of hot gases containing condensible tars. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Prausnitz, J.M.

    1980-05-01

    This research is concerned with the fundamental physical chemistry and thermodynamics of condensation of tars (dew points) from the vapor phase at advanced temperatures and pressures. Fundamental quantitative understanding of dew points is important for rational design of heat exchangers to recover sensible heat from hot, tar-containing gases that are produced in coal gasification. This report includes essentially six contributions toward establishing the desired understanding: (1) Characterization of Coal Tars for Dew-Point Calculations; (2) Fugacity Coefficients for Dew-Point Calculations in Coal-Gasification Process Design; (3) Vapor Pressures of High-Molecular-Weight Hydrocarbons; (4) Estimation of Vapor Pressures of High-Boiling Fractions in Liquefied Fossil Fuels Containing Heteroatoms Nitrogen or Sulfur; and (5) Vapor Pressures of Heavy Liquid Hydrocarbons by a Group-Contribution Method.

  3. “Towards building better linkages between aqueous phase chemistry and microphysics in CMAQ”

    Science.gov (United States)

    Currently, CMAQ’s aqueous phase chemistry routine (AQCHEM-base) assumes Henry’s Law equilibrium and employs a forward Euler method to solve a small set of oxidation equations, considering the additional processes of aitken scavenging and wet deposition in series and e...

  4. Microalgae growth on the aqueous phase from Hydrothermal Liquefaction of the same microalgae

    NARCIS (Netherlands)

    Garcia Alba, Laura; Torri, Cristian; Fabbri, Daniele; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2013-01-01

    Cultivation of Desmodesmus sp. microalgae in the recycled aqueous phase (AP) recovered after Hydrothermal Liquefaction (HTL) of the same microalgae was studied to evaluate the potential of nutrients recycling. AP dilution ratio was systematically varied, using either water or water enriched with

  5. Lignin solubilization and aqueous phase reforming for the production of aromatic chemicals and hydrogen

    NARCIS (Netherlands)

    Zakzeski, J.|info:eu-repo/dai/nl/326160256; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2011-01-01

    The solubilization and aqueous phase reforming of lignin, including kraft, soda, and alcell lignin along with sugarcane bagasse, at low temperatures (T≤498 K) and pressures (P≤29 bar) is reported for the first time for the production of aromatic chemicals and hydrogen. Analysis of lignin model

  6. Analysis of continuous fermentation processes in aqueous two-phase systems

    Energy Technology Data Exchange (ETDEWEB)

    Jarzebski, A B; Malinowski, J J [Polish Academy of Sciences, Gliwice (Poland). Inst. of Chemical Engineering; Goma, G; Soucaille, P [INSA, 31 - Toulouse (France). Dept. de Genie Biochimique et Alimentaire

    1992-05-01

    Simulations of continuous ethanol or acetonobutylic fermentations in aqueous two-phase systems show that at high substrate feed concentrations it is possible to obtain solvent productivities about 25-40% higher than in conventional systems with cell recycle if the biomass bleed rate is kept about one tenth of the value of D. (orig.).

  7. Gas-Phase Oxidation of Aqueous Ethanol by Nanoparticle Vanadia/Anatase Catalysts

    DEFF Research Database (Denmark)

    Jørgensen, Betina; Kristensen, Steffen Buus; Kunov-Kruse, Andreas Jonas

    2009-01-01

    The gas-phase oxidation of aqueous ethanol with dioxygen has been examined with a new nanoparticle V2O5/TiO2 catalyst. Product selectivity could to a large extent be controlled by small alterations of reaction parameters, allowing production of acetaldehyde at a selectivity higher than 90%, near...

  8. Carbon-coated ceramic membrane reactor for production of hydrogen via aqueous phase reforming of sorbitol

    NARCIS (Netherlands)

    Neira d'Angelo, M.F.; Ordomskiy, V.; Schouten, J.C.; Schaaf, van der J.; Nijhuis, T.A.

    2014-01-01

    Hydrogen was produced by aqueous-phase reforming (APR) of sorbitol in a carbon-on-alumina tubular membrane reactor (4 nm pore size, 7 cm long, 3 mm internal diameter) that allows the hydrogen gas to permeate to the shell side, whereas the liquid remains in the tube side. The hydrophobic nature of

  9. Development of linear free energy relationships for aqueous phase radical-involved chemical reactions.

    Science.gov (United States)

    Minakata, Daisuke; Mezyk, Stephen P; Jones, Jace W; Daws, Brittany R; Crittenden, John C

    2014-12-02

    Aqueous phase advanced oxidation processes (AOPs) produce hydroxyl radicals (HO•) which can completely oxidize electron rich organic compounds. The proper design and operation of AOPs require that we predict the formation and fate of the byproducts and their associated toxicity. Accordingly, there is a need to develop a first-principles kinetic model that can predict the dominant reaction pathways that potentially produce toxic byproducts. We have published some of our efforts on predicting the elementary reaction pathways and the HO• rate constants. Here we develop linear free energy relationships (LFERs) that predict the rate constants for aqueous phase radical reactions. The LFERs relate experimentally obtained kinetic rate constants to quantum mechanically calculated aqueous phase free energies of activation. The LFERs have been applied to 101 reactions, including (1) HO• addition to 15 aromatic compounds; (2) addition of molecular oxygen to 65 carbon-centered aliphatic and cyclohexadienyl radicals; (3) disproportionation of 10 peroxyl radicals, and (4) unimolecular decay of nine peroxyl radicals. The LFERs correlations predict the rate constants within a factor of 2 from the experimental values for HO• reactions and molecular oxygen addition, and a factor of 5 for peroxyl radical reactions. The LFERs and the elementary reaction pathways will enable us to predict the formation and initial fate of the byproducts in AOPs. Furthermore, our methodology can be applied to other environmental processes in which aqueous phase radical-involved reactions occur.

  10. Dynamic speciation analysis of atrazine in aqueous latex nanoparticle dispersions using solid phase microextraction (SPME)

    NARCIS (Netherlands)

    Benhabib, K.; Town, R.M.; Leeuwen, van H.P.

    2009-01-01

    Solid phase microextraction (SPME) is applied in the dynamic speciation analysis of the pesticide atrazine in an aqueous medium containing sorbing latex nanoparticles. It is found that the overall rate of extraction of the analyte is faster than in the absence of nanoparticles and governed by the

  11. Solid phase microextraction speciation analysis of triclosan in aqueous mediacontaining sorbing nanoparticles

    NARCIS (Netherlands)

    Zielinska, K.

    2014-01-01

    Solid phase microextraction (SPME) is applied in the speciation analysis of the hydrophobic compound triclosan in an aqueous medium containing sorbing SiO2 nanoparticles (NPs). It is found that these NPs, as well as their complexes with triclosan, partition between the bulk medium and the solid

  12. Utilizing hydrogen in aqueous phase conversion of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Baoxiang; Zhao, Chen; Li, Xuebing; Lercher, Johannes A. [Technische Univ. Muenchen, Garching (Germany). Technische Chemie II

    2010-12-30

    Hydrogen generation and selective hydrodeoxygenation of biomass are the key for the successful integration of biogenic carbon resources for energy carriers and intermediates. This includes the generation of hydrogen from biomass in the liquid phase and more importantly, for the direct utilization of the hydrogen generated into the molecules. We will outline this strategy with two groups of oxofunctionalized molecules, i.e., glycerol as example for the aliphatic group and substituted phenols as the aromatic group. (orig.)

  13. Deep Recycling of Sedimentary Lithologies in Subduction Zones: Geochemical and Physical Constraints from Phase Equilibria and Synchrotron-Based Multi-Anvil Experiments at 15-25 GPa

    Science.gov (United States)

    Rapp, R. P.; Nishiyama, N.; Irifune, T.; Inoue, T.; Yamasaki, D.

    2003-12-01

    Ocean island basalts (OIBs) provide geochemical evidence for the presence of crustally-derived sedimentary material in the deep mantle plume source region for EM-type OIBs, and global seismic tomography provides us with dramatic images of subducted slabs, presumably carrying a sediment component, penetrating through the transition zone and into the lower mantle, in some cases to the core-mantle boundary. In an effort to better constrain the geochemical effects of deeply recycled sedimentary material in subduction zones, and their role in the petrogenesis of EM-type OIBs, we have undertaken a series of phase equlibria experiments in the multi-anvil apparatus at 10-25 GPa, using natural sediment lithologies as starting materials. The goal of these experiments is to identify the dominant phases in deeply subducted sediments, constrain their P-T stability limits, and to assess their role in crustal recycling and element redistribution in the deep mantle during subduction. The phase equilibria experiments were performed in a 2000-ton Kawai-type apparatus, using tungsten carbide cubes with 3 mm TEL and Cr-doped MgO and zirconia pressure media. A cylindrical lanthanum chromite heater was used, along with short (gold capsules to minimize thermal gradients and to retain the small amounts of water (< 1 wt%) present in the starting material, and long run-durations (12-48 hours) in order to facilitate future analyses of the dominant phases for key trace elements using the ion microprobe. Our preliminary results at 10-25 GPa indicate that K-hollandite (KalSi3O3) and stishovite are the primary high-pressure phases in the sediment composition, with subordinate garnet and an as-yet-unidentified (possibly hydrous) Al-silicate phase present as well. These results suggest that K-hollandite is the primary repository for incompatible elements (e.g., La, Ce, Sr, Ba, Rb, etc., and the heat-producing elements K, U and Th) in sedimentary material recycled into the deep mantle via

  14. Study of phase equilibria and glass formation in the CaO-WO3-P2O5 system

    International Nuclear Information System (INIS)

    Bielis, I.Ya.

    1980-01-01

    The method of quenching has been used to investigate the liquidus surface of a portion of the CaO-WO 3 -P 2 O 5 system limited by the Ca(PO 3 ) 2 -W 2 O 3 (PO 4 ) 2 and CaWO 4 -Ca 2 P 2 O 7 cross-sections. The primary crystallization fields on the compounds: WO 3 , W 2 O 3 (PO 4 ) 2 , CaWO 4 , Ca 2 P 7 O 7 , Ca(PO 3 ) 2 are separated. The liquidus surface isotherms at 900, 1000, 1100 and 1200 deg C have been plotted on the concentration triangle plane. It has been found that the cross-sections of W 2 O 3 (PO 4 ) 2 -Ca(PO 3 ) 2 , WO 3 -Ca(PO 3 ) 2 , WO 3 -Ca 2 P 2 O 7 and CaWO 4 -Ca 2 P 2 O 7 are eutectic-type quasi-binary systems. The position of the glass transition region in the CaO-WO 3 -P 2 O 5 system has been determined for the treatment temperatures of 1100, 1200 and 1300 deg C and a correlation between the configuration of the glass transition region and the phase diagram of the system has been demonstrated [ru

  15. Modeling of the phase equilibria of polystyrene in methylcyclohexane with semi-empirical quantum mechanical methods I.

    Science.gov (United States)

    Wilczura-Wachnik, Hanna; Jónsdóttir, Svava Osk

    2003-04-01

    A method for calculating interaction parameters traditionally used in phase-equilibrium computations in low-molecular systems has been extended for the prediction of solvent activities of aromatic polymer solutions (polystyrene+methylcyclohexane). Using ethylbenzene as a model compound for the repeating unit of the polymer, the intermolecular interaction energies between the solvent molecule and the polymer were simulated. The semiempirical quantum chemical method AM1, and a method for sampling relevant internal orientations for a pair of molecules developed previously were used. Interaction energies are determined for three molecular pairs, the solvent and the model molecule, two solvent molecules and two model molecules, and used to calculated UNIQUAC interaction parameters, a(ij) and a(ji). Using these parameters, the solvent activities of the polystyrene 90,000 amu+methylcyclohexane system, and the total vapor pressures of the methylcyclohexane+ethylbenzene system were calculated. The latter system was compared to experimental data, giving qualitative agreement. Figure Solvent activities for the methylcylcohexane(1)+polystyrene(2) system at 316 K. Parameters aij (blue line) obtained with the AM1 method; parameters aij (pink line) from VLE data for the ethylbenzene+methylcyclohexane system. The abscissa is the polymer weight fraction defined as y2(x1)=(1mx1)M2/[x1M1+(1mx1)M2], where x1 is the solvent mole fraction and Mi are the molecular weights of the components.

  16. Toward stable nickel catalysts for aqueous phase reforming of biomass-derived feedstock under reducing and alkaline conditions

    NARCIS (Netherlands)

    Haasterecht, van T.; Ludding, C.C.I.; Jong, de K.P.; Bitter, J.H.

    2014-01-01

    Nickel nanoparticles supported on carbon nanofibers (CNF) can be stabilized in aqueous phase processes at elevated temperatures and pressures by tuning the reaction conditions to control Ni oxidation and leaching. As a showcase, Ni/CNF was used for the production of hydrogen via aqueous phase

  17. Phase Equilibria of Mixtures Containing Organic Sulfur Species (OSS) and Water/Hydrocarbons: VLE Measurements and Modeling Using the Cubic-Plus-Association Equation of State

    DEFF Research Database (Denmark)

    Awan, Javeed; Tsivintzelis, Ioannis; Breil, Martin

    2010-01-01

    with the cubic-plus-association (CPA) equation of state. Useful remarks are presented about the application of Henry’s constant values to estimate binary interaction parameters of the CPA EoS for the description of whole vapor−liquid equilibria. The results using CPA EoS show that the cross association...

  18. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

    Science.gov (United States)

    Tellinghuisen, Joel

    2010-01-01

    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  19. The Potential of Soave-Redlich-Kwong Equation of State in Describing Phase Equilibria Data at High Pressures for the CO2 + 1-Alcohol Systems

    Czech Academy of Sciences Publication Activity Database

    Teodorescu, M.; Barhala, A.; Wichterle, Ivan

    2005-01-01

    Roč. 49, č. 11 (2005), s. 927-934 ISSN 0035-3930 R&D Projects: GA ČR(CZ) GA104/03/1555; GA AV ČR(CZ) IAA4072102 Institutional research plan: CEZ:AV0Z40720504 Keywords : vapor liquid equilibria * description Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.226, year: 2005

  20. Nutrient removal and energy production from aqueous phase of bio-oil generated via hydrothermal liquefaction of algae.

    Science.gov (United States)

    Shanmugam, Saravanan R; Adhikari, Sushil; Shakya, Rajdeep

    2017-04-01

    Removal of nutrients (phosphorus and nitrogen) as struvite from bio-oil aqueous phase generated via hydrothermal liquefaction of algae was evaluated in this study. Effect of process parameters such as pH, temperature and reaction time on struvite formation was studied. More than 99% of phosphorus and 40-100% ammonium nitrogen were removed under all experimental conditions. X-ray diffraction analysis confirmed the formation of struvite, and the struvite recovered from bio-oil aqueous phase can be used as a slow-release fertilizer. Biogas production from struvite recovered bio-oil aqueous phase showed 3.5 times higher CH 4 yield (182±39mL/g COD) as compared to non-struvite recovered aqueous phase. The results from this study indicate that both struvite and methane can be produced from bio-oil aqueous phase. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Cosolutes effects on aqueous two-phase systems equilibrium formation studied by physical approaches.

    Science.gov (United States)

    Bertoluzzo, M Guadalupe; Rigatuso, Rubén; Farruggia, Beatriz; Nerli, Bibiana; Picó, Guillermo

    2007-10-01

    The effect of urea and sodium salts of monovalent halides on the aqueous polyethyleneglycol solution and binodal diagrams of polyethyleneglycol-potassium phosphate (polyethyleneglycol of molecular mass 1500, 4000, 6000 and 8000) were studied using different physical approaches. The effect of these solutes on the binodal diagram for polyethyleneglycol-potassium phosphate was also investigated. The cosolutes affected in a significant manner the water structured around the ethylene chain of polyethyleneglycol inducing a lost of this. The equilibrium curves for the aqueous two-phase systems were fitting very well by a sigmoidal function with two parameters, which are closely related with the cosolute structure making or breaking capacity on the water ordered.

  2. Phase Equilibria Study in the TeO2-Na2O-SiO2 System in Air Between 723 K (500 °C) and 1473 K (1200 °C)

    Science.gov (United States)

    Santoso, Imam; Taskinen, Pekka

    2016-08-01

    Knowledge of phase equilibria in the TeO2-Na2O-SiO2 system at elevated temperatures is important for ceramic and glass industries and for improving the operation of the smelting process of tellurium-containing materials. A review of previous investigations has indicated, however, that there are omissions in the available datasets on the liquidus temperatures of the molten TeO2-Na2O-SiO2 mixtures. The employed experimental method included equilibration of mixtures made from high purity oxides, rapid quenching of the equilibrated samples in water and followed by compositional analysis of the phases using an electron probe X-ray microanalyzer. The liquidus and phase equilibria in the TeO2-SiO2, TeO2-Na2O, and SiO2-TeO2-Na2O systems have been studied for a wide range of compositions between 723 K (500 °C) and 1473 K (1200 °C) at TeO2, SiO2, and Na2SiO3 saturations. New data have been generated in the SiO2-TeO2-Na2O system at SiO2 saturation. The liquidus compositions in the TeO2-Na2O system at TeO2 saturation have been compared with the previous data and an assessed phase diagram.

  3. Explicit modeling of volatile organic compounds partitioning in the atmospheric aqueous phase

    Directory of Open Access Journals (Sweden)

    C. Mouchel-Vallon

    2013-01-01

    Full Text Available The gas phase oxidation of organic species is a multigenerational process involving a large number of secondary compounds. Most secondary organic species are water-soluble multifunctional oxygenated molecules. The fully explicit chemical mechanism GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere is used to describe the oxidation of organics in the gas phase and their mass transfer to the aqueous phase. The oxidation of three hydrocarbons of atmospheric interest (isoprene, octane and α-pinene is investigated for various NOx conditions. The simulated oxidative trajectories are examined in a new two dimensional space defined by the mean oxidation state and the solubility. The amount of dissolved organic matter was found to be very low (yield less than 2% on carbon atom basis under a water content typical of deliquescent aerosols. For cloud water content, 50% (isoprene oxidation to 70% (octane oxidation of the carbon atoms are found in the aqueous phase after the removal of the parent hydrocarbons for low NOx conditions. For high NOx conditions, this ratio is only 5% in the isoprene oxidation case, but remains large for α-pinene and octane oxidation cases (40% and 60%, respectively. Although the model does not yet include chemical reactions in the aqueous phase, much of this dissolved organic matter should be processed in cloud drops and modify both oxidation rates and the speciation of organic species.

  4. Effect of temperature on acid-base equilibria in separation techniques. A review.

    Science.gov (United States)

    Gagliardi, Leonardo G; Tascon, Marcos; Castells, Cecilia B

    2015-08-19

    Studies on the theoretical principles of acid-base equilibria are reviewed and the influence of temperature on secondary chemical equilibria within the context of separation techniques, in water and also in aqueous-organic solvent mixtures, is discussed. In order to define the relationships between the retention in liquid chromatography or the migration velocity in capillary electrophoresis and temperature, the main properties of acid-base equilibria have to be taken into account for both, the analytes and the conjugate pairs chosen to control the solution pH. The focus of this review is based on liquid-liquid extraction (LLE), liquid chromatography (LC) and capillary electrophoresis (CE), with emphasis on the use of temperature as a useful variable to modify selectivity on a predictable basis. Simplified models were evaluated to achieve practical optimizations involving pH and temperature (in LLE and CE) as well as solvent composition in reversed-phase LC. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Phase equilibria and crystal chemistry in the ternary system BaO-TiO 2-Nb 2O 5. II. New barium polytitanates with <5 mole% Nb 2O 5

    Science.gov (United States)

    Roth, R. S.; Ettlinger, L. D.; Parker, H. S.

    1987-06-01

    Four new compounds were found in the BaO-TiO 2-Nb 2O 5 system, each containing orth ≈ 9.9A˚, b mon ≈ a orth ≈ 17A˚). Ba 14Ti 40Nb 2O 99 is a 20-layer orthorhombic phase, Cmc*, withc ≈ 46.86A˚. Ba 10Ti 28Nb 2O 72 is a 7-layer monoclinic phase, C2m, c ≈ 16.72A˚, β ≈ 101.2°. Ba 18Ti 54Nb 2O 132 is a 13-layer monoclinic phase, C2m, c ≈ 30.65A˚, β ≈ 96°. The compositions were derived by analogy to the layers in Ba 4Ti 13 O 30 and Ba 6Ti 17O 40 and are consistent with limited phase equilibria data.

  6. Phase equilibria in M-X-X' and M-Al-X ternary systems (M-transition metal, X,X'-B,C,N,Si) and crystal chemistry of ternary compounds

    International Nuclear Information System (INIS)

    Gusev, A.I.

    1996-01-01

    The data on phase equilibria in the M-X-X' and M-Al-X ternary systems (M-transition metal of 3 to 8 groups, X-B,C, N, Si) have been considered and summarized. modern oxygen-free advanced ceramics is based on these ternary systems. Phase diagrams of the 130 ternary systems have been discussed, more than two hundred ternary phases forming in these systems have been systematized and described. The typical crystal structures of ternary compounds and phase have been considered, the common and distinctive features of these structures have been analysed. It has been shown that the ternary compounds with octahedral atomic groups XM 6 have a regions of homogeneity. Refs. 240

  7. Institutions, Equilibria and Efficiency

    DEFF Research Database (Denmark)

    Competition and efficiency is at the core of economic theory. This volume collects papers of leading scholars, which extend the conventional general equilibrium model in important ways. Efficiency and price regulation are studied when markets are incomplete and existence of equilibria in such set...... in OLG, learning in OLG and in games, optimal pricing of derivative securities, the impact of heterogeneity...

  8. Aqueous preparation of polyethylene glycol/sulfonated graphene phase change composite with enhanced thermal performance

    International Nuclear Information System (INIS)

    Li, Hairong; Jiang, Ming; Li, Qi; Li, Denian; Chen, Zongyi; Hu, Waping; Huang, Jing; Xu, Xizhe; Dong, Lijie; Xie, Haian; Xiong, Chuanxi

    2013-01-01

    Highlights: • We report an aqueous preparation technique of PEG/graphene phase change composite. • Hydrophilic sulfonated graphene (SG) nanosheets were synthesized. • Large increase in thermal conductivity is attained at low SG loading. • High latent heat is retained due to the low filler loading. • Affinity between SG and PEG contributes to the enhanced thermal performance. - Abstract: A polyethylene glycol (PEG)/sulfonated graphene (SG) phase change composite with enhanced thermal performance was prepared by solution processing in aqueous medium. It is remarkable that the addition of only 4 wt.% of SG to PEG could lead to a four times higher increase in thermal conductivity and a slight decrease in the phase change enthalpy, which is attributed to the formation of efficient thermal conductive network within the PEG matrix relevant to the excellent thermal property and unique 2-dimensional morphology of graphene as well as strong interface affinity between PEG matrix and SG nanosheets. The aqueous preparation technique is expected to pioneer a new way to prepare environment friendly organic phase change materials, and the production of PEG/SG composites is potentially scalable due to the facile fabricating process

  9. Extraction of Oxytetracycline Hydrochloride in Aqueous Two-phase System of Acetone and Ammonium Sulfate

    International Nuclear Information System (INIS)

    Han, J.

    2013-01-01

    Summary: Aqueous two-phase system (ATPS) is an efficient implement for separation of various substrates, and extracted by an aqueous two-phase system has been successful ly applied in the downstream processing of various biological compounds. In this research, the extraction of oxytetracycline hydrochloride (OTC-HCl) was carried out in an aqueous two-phase system containing acetone and ammonium sulfate solution, which partitioned the antibiotic to the upper phase. The effects of some parameters on the extraction efficiency of OTC-HCl were studied in detail, including temperature, the volume of acetone, the pH value of ammonium sulfate solution, the concentrations of (NH/sub 4/)/sub 2/ SO/sub 4/ and OTC-HCl. The results showed that the volume of acetone, the pH value of ammonium sulfate solution and the concentration of OTC-HCl in feed had significant effects on the extraction efficiency of OTC-HCl, but the effects of temperature on the extraction of OTC-HCl was not obvious. (author)

  10. Extraction of Oxytetracycline Hydrochloride in Aqueous Two-phase System of Acetone and Ammonium Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Han, J. [Jiangsu Univ., Zhenjiang (China). Dept. of Food and Biological Engineering

    2013-02-15

    Summary: Aqueous two-phase system (ATPS) is an efficient implement for separation of various substrates, and extracted by an aqueous two-phase system has been successful ly applied in the downstream processing of various biological compounds. In this research, the extraction of oxytetracycline hydrochloride (OTC-HCl) was carried out in an aqueous two-phase system containing acetone and ammonium sulfate solution, which partitioned the antibiotic to the upper phase. The effects of some parameters on the extraction efficiency of OTC-HCl were studied in detail, including temperature, the volume of acetone, the pH value of ammonium sulfate solution, the concentrations of (NH/sub 4/)/sub 2/ SO/sub 4/ and OTC-HCl. The results showed that the volume of acetone, the pH value of ammonium sulfate solution and the concentration of OTC-HCl in feed had significant effects on the extraction efficiency of OTC-HCl, but the effects of temperature on the extraction of OTC-HCl was not obvious. (author)

  11. Graphite-supported platinum catalysts: Effects of gas and aqueous phase treatments

    Energy Technology Data Exchange (ETDEWEB)

    Vleeming, J.H.; Kuster, B.F.M.; Marin, G.B. [Eindhoven Univ. of Technology (Netherlands)] [and others

    1997-03-01

    The effects on the platinum particle diameter and the available platinum surface area of a graphite-supported platinum catalyst resulting from pretreatments and from performing a selective oxidation reaction are investigated. In the gas phase considerable catalyst sintering occurs only in the presence of oxygen at 773 K due to extensive carbon burn-off, whereas in an aqueous phase platinum particle growth is limited upon oxidative treatment. A hydrogen treatment in aqueous phase at 363 K causes platinum particle growth, aggregate formation, and covering of metal sites. These phenomena become more important with increasing pH. Platinum particle growth and aggregate formation are attributed to platinum particle rather than platinum adatom mobility and is caused by the destruction of the oxygen-containing surface groups on the graphite support, which serve as anchorage sites for the platinum particles. Site covering is caused by products originating from the graphite support, which are formed as a result of the reductive treatments. When performing the aqueous phase oxidation of methyl {alpha}-D-glucopyranoside at 323 K and a pH of 9, catalyst modifications are small under oxidative conditions. Exposure of the catalyst for several hours to methyl {alpha}-D-glucopyranoside under the same conditions but in the absence of oxygen causes site covering. 50 refs., 9 figs., 1 tab.

  12. Extended UNIQUAC Model for Correlation and Prediction of Vapor-Liquid-Liquid-Solid Equilibria in Aqueous Salt Systems Containing Non-Electrolytes. Part B. Alcohol (Ethanol, Propanols, Butanols) - Water-salt systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Iliuta, Maria Cornelia; Rasmussen, Peter

    2004-01-01

    The Extended UNIQUAC model for electrolyte solutions is an excess Gibbs energy function consisting of a Debye-Huckel term and a term corresponding to the UNIQUAC equation. For vapor-liquid equilibrium calculations, the fugacities of gas-phase components are calculated with the Soave-Redlich-Kwong......The Extended UNIQUAC model for electrolyte solutions is an excess Gibbs energy function consisting of a Debye-Huckel term and a term corresponding to the UNIQUAC equation. For vapor-liquid equilibrium calculations, the fugacities of gas-phase components are calculated with the Soave...... solid-liquid-vapor equilibrium and thermal property data for strongly non-ideal systems. In this work, the model is extended to aqueous salt systems containing higher alcohols. The calculations are based on an extensive database consisting of salt solubility data, vapor liquid equilibrium data...

  13. Investigation of the phase equilibria and phase transformations associated with the Bi2Sr2CaCu2Oy superconductor

    International Nuclear Information System (INIS)

    Holesinger, T.

    1993-01-01

    The solid solution region and reaction kinetics of the Bi 2 Sr 2 CaCu 2 O y (2212) superconductor were examined as a function of temperature and oxygen partial pressure. Crystallization studies from the glassy and molten states were undertaken to determine the phase transformation and kinetics associated with the formation of 2212 and other competing phases. Crystallization of nominal 2212 glasses was found to proceed in two steps with the formation of Bi 2 Sr 2-x Ca x CuO y (2201) and Cu 2 O followed by Bi 2 Sr 3-x Ca x O y , CaO, and SrO. The 2212 phase converts from the 2201 phase with increasing temperatures. However, its formation below 800 C was kinetically limited. At 800 C and above, a nearly full conversion to the 2212 phase was achieved after only one minute although considerably longer anneal times were necessary for the system to reach equilibrium. In low oxygen partial pressures, the solidus is reduced to approximately 750 C. Solidification studies revealed an eutectic structure separating the incongruently melting 2212/2201 phases at high oxygen partial pressures from the congruently melting Bi 2 Sr 3-x Ca x O y (23x) and Bi 2 Sr 2-x Ca x O y (22x) phases present at low oxygen partial pressures. During solidification in various oxygen partial pressures, the separation of CaO in the melt and the initial crystallization of alkaline-earth cuprates leaves behind a Bi-rich liquid from which it is impossible to form single-phase 2212. Hence, significant amounts of 2201 were also present in these samples. These problems could be reduced by melt processing in inert atmospheres. Bulk 2212 material produced in this manner was found to possess high transition temperatures, high intergranular critical current densities below 20K, and modest critical current densities at 77K

  14. Quantification and speciation of volatile fatty acids in the aqueous phase.

    Science.gov (United States)

    Lee, Jechan; Kim, Jieun; Oh, Jeong-Ik; Lee, Sang-Ryong; Kwon, Eilhann E

    2017-11-01

    This study lays great emphasis on establishing a reliable analytical platform to quantify and specify volatile fatty acids (VFAs) in the aqueous phase by derivatizing VFAs into their corresponding alkyl esters via thermally-induced rapid esterification (only 10 s reaction time). To this end, reaction conditions for the thermally-induced rapid esterification are optimized. A volumetric ratio of 0.5 at 400 °C for VFA/methanol is identified as the optimal reaction conditions to give ∼90% volatile fatty acid methyl ester (VFAME) yield. To maintain a high yield of VFAMEs, this study suggests that dilution of the sample to an optimum concentration (∼500 ppm for each VFA) is required. Derivatization of VFAs into VFAMEs via the thermally-induced rapid esterification is more reliable to quantify and specify VFAs in the aqueous phase than conventional colorimetric method. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. A chromatographic determination of water in non-aqueous phases of solvent extraction systems

    International Nuclear Information System (INIS)

    Lyle, S.J.; Smith, D.B.

    1975-01-01

    The disadvantages of the Karl Fischer method for the determination of water in the non-aqueous phases of solvent extraction systems are pointed out, and a gas chromatographic method is described which is claimed to be potentially capable of overcoming these disadvantages. The method, as described, was developed to satisfy conditions relevant to measurement of the transfer rate of water from an aqueous phase into tri-n-butylphosphate in toluene, but it can be used for water determination in other solvent extraction systems. The apparatus used is described in detail. The concentration of water in water-saturated TBP was found to be 3.56 mol/litre, compared with a value of 3.55 obtained by Karl Fischer titration and previous literature values of 3.59 and 3.57. Measurements of water content in benzene solutions of long chain alkylamines were also sucessfully carried out. (U.K.)

  16. Compact and highly stable quantum dots through optimized aqueous phase transfer

    Science.gov (United States)

    Tamang, Sudarsan; Beaune, Grégory; Poillot, Cathy; De Waard, Michel; Texier-Nogues, Isabelle; Reiss, Peter

    2011-03-01

    A large number of different approaches for the aqueous phase transfer of quantum dots have been proposed. Surface ligand exchange with small hydrophilic thiols, such as L-cysteine, yields the lowest particle hydrodynamic diameter. However, cysteine is prone to dimer formation, which limits colloidal stability. We demonstrate that precise pH control during aqueous phase transfer dramatically increases the colloidal stability of InP/ZnS quantum dots. Various bifunctional thiols have been applied. The formation of disulfides, strongly diminishing the fluorescence QY has been prevented through addition of appropriate reducing agents. Bright InP/ZnS quantum dots with a hydrodynamic diameter <10 nm and long-term stability have been obtained. Finally we present in vitro studies of the quantum dots functionalized with the cell-penetrating peptide maurocalcine.

  17. Aqueous phase partitioning of hexachlorocyclohexane (HCH) isomers by biosurfactant produced by Pseudomonas aeruginosa WH-2

    International Nuclear Information System (INIS)

    Sharma, Suman; Singh, Partapbir; Raj, Mayil; Chadha, Bhupinder Singh; Saini, Harvinder Singh

    2009-01-01

    The different isomers of technical-grade hexachlorocyclohexane (t-HCH) including the insecticidal γ-isomer, commonly known as lindane, have been reported to be toxic, carcinogenic and endocrine disrupters. The spatial arrangements of the chlorine atoms on different isomers and low aqueous phase solubility contribute to their persistence in environment, β-HCH being the most resistance to transformation. The biosurfactant preparation of Pseudomonas aeruginosa isolate WH-2 was evaluated for its ability to improve the aqueous phase partitioning of different isomers of HCH-muck. Further, the ability of biosurfactant preparation to emulsify HCH and n-hexadecane was checked under different conditions, usually characteristic of sites contaminated with pollutants viz. wide range of pH, temperature, and salinity. The data obtained from this study will be helpful in designing suitable bioremediation strategies for huge stock piles of HCH-muck and sites polluted by reckless use/disposal of HCH-isomers.

  18. Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

    Science.gov (United States)

    Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

    2017-11-01

    A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models.

    Science.gov (United States)

    Flores-Alsina, Xavier; Kazadi Mbamba, Christian; Solon, Kimberly; Vrecko, Darko; Tait, Stephan; Batstone, Damien J; Jeppsson, Ulf; Gernaey, Krist V

    2015-11-15

    There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico-chemical processes after many years of mainly focusing on biokinetics. Indeed, future modelling needs, such as a plant-wide phosphorus (P) description, require a major, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems. In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation/pairing is presented and interfaced with industry standard models. The module accounts for extensive consideration of non-ideality, including ion activities instead of molar concentrations and complex ion pairing. The general equilibria are formulated as a set of Differential Algebraic Equations (DAEs) instead of Ordinary Differential Equations (ODEs) in order to reduce the overall stiffness of the system, thereby enhancing simulation speed. Additionally, a multi-dimensional version of the Newton-Raphson algorithm is applied to handle the existing multiple algebraic inter-dependencies. The latter is reinforced with the Simulated Annealing method to increase the robustness of the solver making the system not so dependent of the initial conditions. Simulation results show pH predictions when describing Biological Nutrient Removal (BNR) by the activated sludge models (ASM) 1, 2d and 3 comparing the performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) treatment plant configuration under different anaerobic/anoxic/aerobic conditions. The same framework is implemented in the Benchmark Simulation Model No. 2 (BSM2) version of the Anaerobic Digestion Model No. 1 (ADM1) (WWTP3) as well, predicting pH values at different cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated, by implementing the aqueous phase chemistry module in some

  20. Platinum–Rhenium synergy on reducible oxide supports in aqueous-phase glycerol reforming

    NARCIS (Netherlands)

    Ciftci, A.; Eren, S.; Ligthart, D.A.J.M.; Hensen, E.J.M.

    2014-01-01

    A significant support effect was observed for the aqueous-phase reforming (APR) of glycerol over a series of Pt- and PtRe-loaded ceria-, ceria–zirconia-, zirconia-, and titania-supported catalysts. Glycerol conversion rates decreased in the order Pt/TiO2>Pt/ZrO2>Pt/CeZrO2>Pt/CeO2. Upon addition of

  1. Correlation and Prediction of Thermal Properties and Phase Behaviour for a Class of Aqueous Electrolyte Systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter; Gani, Rafiqul

    1996-01-01

    An extended UNIQUAC model is used to describe phase behaviour (VLE, SLE) and thermal properties (heat of mixing, heat capacity) for aqueous solutions containing ions like (Na+, K+, H+) (Cl-, NO3-, SO42-, OH-, CO3-). A linear temperature dependence of the binary interaction parameters allows good...... agreement with experimental data in the temperature range 0-110 degrees C. Copyright (C) 1996 Elsevier Science Ltd...

  2. Aqueous-phase reforming of crude glycerol : effect of impurities on hydrogen production

    NARCIS (Netherlands)

    Boga, Dilek A.; Liu, Fang; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2016-01-01

    The aqueous-phase reforming (APR) of a crude glycerol that originates from an industrial process and the effect of the individual components of crude glycerol on APR activity have been studied over 1 wt% Pt/Mg-Al) O, 1 wt% Pt/Al2O3, 5 wt% Pt/Al2O3 and 5 wt% Pt/C catalysts at 29 bar and 225 degrees

  3. Ru decorated carbon nanotubes - a promising catalyst for reforming bio-based acetic acid in the aqueous phase

    NARCIS (Netherlands)

    de Vlieger, Dennis; Lefferts, Leonardus; Seshan, Kulathuiyer

    2014-01-01

    Catalytic reforming of biomass derived waste streams in the aqueous phase is a promising process for the production of sustainable hydrogen. Acetic acid will be a major component (up to 20 wt%) in many anticipated gasification feed streams (e.g. the aqueous fraction of pyrolysis oil). Conventional

  4. Non-conventional solvents in liquid phase microextraction and aqueous biphasic systems.

    Science.gov (United States)

    An, Jiwoo; Trujillo-Rodríguez, María J; Pino, Verónica; Anderson, Jared L

    2017-06-02

    The development of rapid, convenient, and high throughput sample preparation approaches such as liquid phase microextraction techniques have been continuously developed over the last decade. More recently, significant attention has been given to the replacement of conventional organic solvents used in liquid phase microextraction techniques in order to reduce toxic waste and to improve selectivity and/or extraction efficiency. With these objectives, non-conventional solvents have been explored in liquid phase microextraction and aqueous biphasic systems. The utilized non-conventional solvents include ionic liquids, magnetic ionic liquids, and deep eutectic solvents. They have been widely used as extraction solvents or additives in various liquid phase microextraction modes including dispersive liquid-liquid microextraction, single-drop microextraction, hollow fiber-liquid phase microextraction, as well as in aqueous biphasic systems. This review provides an overview into the use of non-conventional solvents in these microextraction techniques in the past 5 years (2012-2016). Analytical applications of the techniques are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Purification of Active Myrosinase from Plants by Aqueous Two-Phase Counter-Current Chromatography

    Science.gov (United States)

    Wade, Kristina L.; Ito, Yoichiro; Ramarathnam, Aarthi; Holtzclaw, W. David; Fahey, Jed W.

    2014-01-01

    Introduction Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (frombroccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors. Objective To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase. Methods A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section). Results Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification. Conclusion Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable. PMID:25130502

  6. Purification of active myrosinase from plants by aqueous two-phase counter-current chromatography.

    Science.gov (United States)

    Wade, Kristina L; Ito, Yoichiro; Ramarathnam, Aarthi; Holtzclaw, W David; Fahey, Jed W

    2015-01-01

    Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (from broccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors. To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase. A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section). Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification. Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Aqueous Two-Phase Extraction of Polyphenols Using a Microchannel System – Process Optimization and Intensification

    Directory of Open Access Journals (Sweden)

    Ivana Rukavina

    2011-01-01

    Full Text Available Polyphenols are one of the most numerous and widespread groups of compounds in the plant world. Nowadays, organic solvents such as methanol, ethanol, acetone, dimethylformamide, ethyl acetate and diethylether are mainly used for the extraction of polyphenols. These solvents require special process conditions and special care in the disposal of the used solvents. In this paper, the extraction of polyphenols from the model solution was performed using the aqueous two-phase system which contains 80.90 % water and represents low burden on the environment. The aqueous solution of gallic acid (GA was used as a model solution of polyphenols. The extraction was performed in the aqueous two-phase system containing PEG6000/H2O/(NH42SO4 in a macroextractor (V=10 mL and microextractor (V=14 ƒμL. The influence of the process parameters, the concentration of gallic acid, pH and composition of the aqueous two-phase system was investigated in order to maximize the partition coefficient. The method of multifactor experimental planning was used to optimize the extraction process and the results were statistically analysed using the evolutionary operation method (EVOP. Optimal operating conditions of the extraction process were pH=6.50, γGA=4.50 g/L, the mass fraction of polyethylene glycol (PEG wPEG=0.1037 g/g and the mass fraction of ammonium sulphate (AMS wAMS=0.0925 g/g. Under these conditions the maximal partition coefficient of K=5.54 and the extraction efficiency of E=89.11 % were achieved and successfully applied for total phenol extraction from white wine in the macro- and microextractor. Approximately the same partition coefficients and extraction efficiency were achieved in the microextractor within a 60-fold shorter residence time.

  8. MULTISYS: Computer code for calculating multicomponent equilibria in high-temperature subcritical and supercritical aqueous systems; MULTISYS: Ein Programm zur Berechnung von Mehrkomponenten-Gleichgewichten in unterkritischen und ueberkritischen waessrigen Systemen

    Energy Technology Data Exchange (ETDEWEB)

    Lvov, S.N.; Akinfiev, N.N.; Bandura, A.V.; Sigon, F.; Perboni, G.

    1999-12-01

    The studies of the corrosion and deposition processes on the structural materials of power plants in high temperature aqueous environments have aroused considerable interest. To understand these processes, it is required to develop a detailed knowledge of thermodynamics that control the solution chemistry, phase relations, kinetics, and mass and heat transport. By knowing the equilibrium composition of the high temperature aqueous solution and by accessing the thermodynamic properties of the corrosion products, it is possible to predict the initial stage of the corrosion processes or oxides deposition, in order to protect plant equipment against damages. (orig.) [German] Studien zur Korrosion und zu Ablagerungsprozessen auf den Komponentenwerkstoffen in Kraftwerken in einer waessrigen Hochtemperaturumgebung sind von betraechtlichem Interesse. Um solche Prozesse zu verstehen, muss ein detailliertes Verstaendnis der Thermodynamik vorhanden sein, welches die Loesungschemie, Phasenbeziehungen, Kinetik sowie Masse- und Waermetransport kontrolliert. Mit dem Wissen um die Gleichgewichtszusammensetzung der waessrigen Hochtemperaturloesung und unter Zugriff auf die thermodynamischen Eigenschaften der Korrosionsprodukte ist es moeglich, die einleitende Stufe von Korrosionsprozessen oder Oxidablagerungen vorherzusagen, um so Anlagenkomponenten vor Schaeden zu schuetzen. (orig.)

  9. The buffering-out effect and phase separation in aqueous solutions of EPPS buffer with 1-propanol, 2-propanol, or 2-methyl-2-propanol at T = 298.15 K

    International Nuclear Information System (INIS)

    Taha, Mohamed; Teng, Han-Lan; Lee, Ming-Jer

    2012-01-01

    Highlights: ► Buffering-out is a new liquid–liquid phase separation containing biological buffer. ► EPPS buffer-induced phase separation of aqueous solutions of aliphatic alcohols. ► Phase diagrams of EPPS + water + 1-propanol/2-propanol/2-methyl-2-propanol are studied. ► EPPS breaks the 1-propanol + water and 2-methyl-2-propanol + water azeotropes. ► The (liquid + liquid) equilibria can be well correlated by the NRTL model. - Abstract: Buffering-out is a new liquid–liquid phase separation phenomenon observed in mixtures containing a buffer as a mass separating agent. The (liquid + liquid) equilibrium (LLE) and (solid + liquid + liquid) equilibrium (SLLE) data were measured for the ternary systems {3-[4-(2-hydroxyethyl)piperazin-1-yl]propanesulfonic acid (EPPS) buffer + 1-propanol, 2-propanol, or 2-methyl-2-propanol + water} at T = 298.15 K under atmospheric pressure. The phase boundary data were fitted to an empirical equation relating to the concentrations of organic solvent and buffer. The effective excluded volume (EEV) values of EPPS were obtained from the phase boundary data. The phase-separation abilities of the investigated aliphatic alcohols were discussed. The reliability of the experimental tie-lines was satisfactorily confirmed by the Othmer–Tobias correlation. The experimental tie-lines data for the ternary systems have been correlated using the NRTL activity coefficient model. The separation of these aliphatic alcohols from their azeotropic aqueous mixtures is of particular interest to industrial process. The addition of the EPPS as an auxiliary agent breaks the (1-propanol + water) and (2-methyl-2-propanol + water) azeotropes. The possibility of using the new phase separation systems in the extraction process is demonstrated by using different dyestuffs.

  10. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol/Sodium Polyacrylate/Salts

    Directory of Open Access Journals (Sweden)

    Adalberto Pessoa Junior

    2011-03-01

    Full Text Available Aqueous two-phase systems consisting of polyethylene glycol (PEG, sodium polyacrylate (NaPAA, and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory-Huggins theory of polymer solutions are presented. Due to strong enthalpic and entropic balancing forces, the hydrophobicity of the added salt has a strong influence on the position of the binodal, which could be reproduced by model calculations.

  11. Principles of interactions in non-aqueous electrolyte solutions

    NARCIS (Netherlands)

    Lyklema, J.

    2013-01-01

    In this paper a review is presented on the molecular interactions in non-aqueous media of low dielectric permittivity. Qualitative and quantitative distinctions with aqueous solutions are emphasized. The reviewed themes include dispersion forces, dissociation and association equilibria,

  12. Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop

    International Nuclear Information System (INIS)

    He Yi; Vargas, Angelica; Kang, Youn-Jung

    2007-01-01

    This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H 3 PO 4 drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 μg L -1 , repeatability of the extraction (R.S.D. -1 for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples

  13. A new approach to establish both stable and metastable phase equilibria for fcc ordered/disordered phase transition: application to the Al–Ni and Ni–Si systems

    International Nuclear Information System (INIS)

    Yuan Xiaoming; Zhang Lijun; Du Yong; Xiong Wei; Tang Ying; Wang Aijun; Liu Shuhong

    2012-01-01

    Both two-sublattice (2SL) and four-sublattice (4SL) models in the framework of the compound energy formalism can be used to describe the fcc ordered/disordered transitions. When transferring the parameters of 2SL disregarding the metastable ordered states into those of 4SL, inconsistence in either stable or metastable phase diagrams could appear, as detected in both Al–Ni and Ni–Si systems. To avoid such a kind of drawback, this behavior was analyzed and investigated in the Ni–Si and Al–Ni systems with the aid of first–principle calculations. Furthermore, a new approach considering both the stable and metastable fcc ordered phase equilibria deduced from the first–principles calculations was proposed to perform a reliable thermodynamic modeling for the fcc ordered/disordered transition. The Ni–Si system was then thermodynamically assessed using the presently proposed approach. The good agreement between the calculation and experiments demonstrates the reliability of the proposed approach. It is expected that the approach is valid for other systems showing complex ordered/disordered transitions. - Highlights: ► We discuss the drawbacks of order/disorder modeling in the Ni–Si and Al–Ni systems. ► We perform ab initio calculation of thermodynamic properties in the Ni–Si system. ► A CALPHAD–type approach is proposed to model the fcc ordered/disordered transition. ► The Ni–Si system was thermodynamically assessed using the new approach.

  14. Improving the treatment of non-aqueous phase TCE in low permeability zones with permanganate.

    Science.gov (United States)

    Chokejaroenrat, Chanat; Comfort, Steve; Sakulthaew, Chainarong; Dvorak, Bruce

    2014-03-15

    Treating dense non-aqueous phase liquids (DNAPLs) embedded in low permeability zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate (MnO4(-)) into LPZs to treat high concentrations of TCE. This was accomplished by conducting transport experiments that quantified the penetration of various permanganate flooding solutions into a LPZ that was spiked with non-aqueous phase (14)C-TCE. The treatments we evaluated included permanganate paired with: (i) a shear-thinning polymer (xanthan); (ii) stabilization aids that minimized MnO2 rind formation and (iii) a phase-transfer catalyst. In addition, we quantified the ability of these flooding solutions to improve TCE destruction under batch conditions by developing miniature LPZ cylinders that were spiked with (14)C-TCE. Transport experiments showed that MnO4(-) alone was inefficient in penetrating the LPZ and reacting with non-aqueous phase TCE, due to a distinct and large MnO2 rind that inhibited the TCE from further oxidant contact. By including xanthan with MnO4(-), the sweeping efficiency increased (90%) but rind formation was still evident. By including the stabilization aid, sodium hexametaphosphate (SHMP) with xanthan, permanganate penetrated 100% of the LPZ, no rind was observed, and the percentage of TCE oxidized increased. Batch experiments using LPZ cylinders allowed longer contact times between the flooding solutions and the DNAPL and results showed that SHMP+MnO4(-) improved TCE destruction by ∼16% over MnO4(-) alone (56.5% vs. 40.1%). These results support combining permanganate with SHMP or SHMP and xanthan as a means of treating high concentrations of TCE in low permeable zones. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Eutectic, monotectic and immiscibility systems of nimesulide with water-soluble carriers: phase equilibria, solid-state characterisation and in-vivo/pharmacodynamic evaluation.

    Science.gov (United States)

    Abdelkader, Hamdy; Abdallah, Ossama Y; Salem, Hesham; Alani, Adam W G; Alany, Raid G

    2014-10-01

    The solid-state interactions of fused mixtures nimesulide (ND) with polyethylene glycol (PEG) 4000, urea or mannitol were studied through constructing thaw-melt phase equilibrium diagrams. The solid-state characteristics were investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Various types of interactions were identified such as the formation of a eutectic system of ND-PEG 4000, monotectic system of ND-urea and complete solid immiscibility of ND with mannitol. The effects of carrier concentrations on the equilibrium solubility and in-vitro dissolution characteristics were studied. Linear increases (R(2)  > 0.99) in the aqueous solubility of ND in various concentrations of PEG 4000 and urea were obtained, whereas mannitol did not exhibit any effect on the solubility of ND. Similar trends were obtained with the dissolution efficiency of the fused mixtures of ND with PEG 4000 and urea compared with the corresponding physical mixtures and untreated drug. The analgesic effects of untreated ND and the selected formulations were investigated by evaluating the drug's ability to inhibit the acetic acid-induced writhing response. The analgesic effect of ND in a eutectic mixture with PEG 4000 and a monotectic mixture with urea was potentiated by 3.2 and 2.7-fold respectively compared with the untreated drug. © 2014 Royal Pharmaceutical Society.

  16. Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid.

    Science.gov (United States)

    Roy, James W; Smith, James E

    2007-01-30

    Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

  17. The phase transport and reactions of γ-irradiated aqueous-ionic liquids

    International Nuclear Information System (INIS)

    Howett, S.; Joseph, J.; Noel, J.J.; Wren, J.C.

    2010-01-01

    A novel technology based on the transfer of chemical species across water/ionic liquid interfaces via specific complexation reactions is currently being considered for the separation and sequestration of metal ion contaminants from radioactive waste effluents in the nuclear fuel cycle. An ideal solvent for these applications should have a high intrinsic selectivity for a targeted metal or group of metals (e.g., trans-Pu actinides, lanthanides, or other fission products), an efficient switching mechanism (between complexation and decomplexation), and a high immiscibility with aqueous solutions. These characteristics must be maintained in the chemical, radiation, and mass transport environments present during the separation process. Ionic liquids (ILs) have an almost negligible vapour pressure and high thermal stability. Their ability to dissolve a wide range of substrate molecules and potential to be highly resilient in radiation fields make ILs particularly promising media. The separation efficiency of the biphasic system will depend on many parameters, including the aqueous oxidation state of the targeted metal ion, and the thermodynamics and kinetics of interfacial transport and metal-ligand complex formation at the water/IL interface or in the IL phase. The most uncertain and unstudied area for these applications is the effect of ionizing radiation on the stability and separation efficiency of the biphasic system. The present study investigates the effect of γ-radiation on gas/IL and water/IL interfacial stability and mass transfer with trihexyltetradecylphosphonium bis(trifluoromethyl-sulfonyl)imide, a phosphonium-based IL. The IL, in contact with either gas or water, was irradiated at a dose rate of 6.4 kGy·h -1 . Gas-phase samples were analyzed by gas chromatography-mass spectrometry (GC-MS) and the changes in the IL and aqueous phases were monitored by conductivity measurements and Raman spectroscopy. In this paper we discuss these observations and their

  18. Mechanisms of catalytic cleavage of benzyl phenyl ether in aqueous and apolar phases

    Energy Technology Data Exchange (ETDEWEB)

    He, Jiayue; Lu, Lu; Zhao, Chen; Mei, Donghai; Lercher, Johannes A.

    2014-03-01

    Catalytic pathways for the cleavage of ether bonds in benzyl phenyl ether (BPE) in liquid phase using Ni- and zeolite-based catalysts are explored. In the absence of catalysts, the C-O bond is selectively cleaved in water by hydrolysis, forming phenol and benzyl alcohol as intermediates, followed by alkylation. The hydronium ions catalyzing the reactions are provided by the dissociation of water at 523 K. Upon addition of HZSM-5, rates of hydrolysis and alkylation are markedly increased in relation to proton concentrations. In the presence of Ni/SiO2, the selective hydrogenolysis dominates for cleaving the Caliphatic-O bond. Catalyzed by the dual-functional Ni/HZSM-5, hydrogenolysis occurs as the major route rather than hydrolysis (minor route). In apolar undecane, the non-catalytic thermal pyrolysis route dominates. Hydrogenolysis of BPE appears to be the major reaction pathway in undecane in the presence of Ni/SiO2 or Ni/HZSM-5, almost completely suppressing radical reactions. Density functional theory (DFT) calculations strongly support the proposed C-O bond cleavage mechanisms on BPE in aqueous and apolar phases. These calculations show that BPE is initially protonated and subsequently hydrolyzed in the aqueous phase. Finally, DFT calculations suggest that the radical reactions in non-polar solvents lead to primary benzyl and phenoxy radicals in undecane, which leads to heavier condensation products as long as metals are absent for providing dissociated hydrogen.

  19. Novel Displacement Agents for Aqueous 2-Phase Extraction Can Be Estimated Based on Hybrid Shortcut Calculations.

    Science.gov (United States)

    Kress, Christian; Sadowski, Gabriele; Brandenbusch, Christoph

    2016-10-01

    The purification of therapeutic proteins is a challenging task with immediate need for optimization. Besides other techniques, aqueous 2-phase extraction (ATPE) of proteins has been shown to be a promising alternative to cost-intensive state-of-the-art chromatographic protein purification. Most likely, to enable a selective extraction, protein partitioning has to be influenced using a displacement agent to isolate the target protein from the impurities. In this work, a new displacement agent (lithium bromide [LiBr]) allowing for the selective separation of the target protein IgG from human serum albumin (represents the impurity) within a citrate-polyethylene glycol (PEG) ATPS is presented. In order to characterize the displacement suitability of LiBr on IgG, the mutual influence of LiBr and the phase formers on the aqueous 2-phase system (ATPS) and partitioning is investigated. Using osmotic virial coefficients (B22 and B23) accessible by composition gradient multiangle light-scattering measurements, the precipitating effect of LiBr on both proteins and an estimation of both protein partition coefficients is estimated. The stabilizing effect of LiBr on both proteins was estimated based on B22 and experimentally validated within the citrate-PEG ATPS. Our approach contributes to an efficient implementation of ATPE within the downstream processing development of therapeutic proteins. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  20. Séparations par changement de phase. Etude et représentation des équilibres liquide-vapeur Separation by Phase Hange. Study and Computing Liquid-Vapor Equilibria

    Directory of Open Access Journals (Sweden)

    Asselineau L.

    2006-11-01

    Full Text Available Pour concevoir et optimiser les principales opérations de séparation (particulièrement les distillations avec ou sans solvant et l'extraction liquide-liquide on doit disposer de méthodes de corrélation ou, mieux, de prédiction des équilibres entre phases. A basse pression, et pour les mélanges d'hydrocarbures, les résultats présentés permettent la prévision des coefficients d'équilibre, même pour les séparations les plus délicates. En présence de constituants polaires, les données expérimentales d'équilibre liquide-liquide et liquide-vapeur de mélanges binaires et ternaires peuvent être simultanément corrélées dans le but de simuler et d'optimiser les distillations azéotropiques ou extractives. Sous haute pression, et particulièrement aux abords immédiats du point critique, le choix d'une équation d'état conduit à un traitement unitaire des phases en présence et permet, en particulier, la prédiction du lieu des points critiques des mélanges d'hydrocarbures et la corrélation de ce lieu en présence de solvants polaires. To determine and optimize the main separation operations (in particular distillations with or without a solvent, and liquid-liquid extraction correlation methods must be available or, better yet, methods of predicting phase equilibria. At low pressure and for hydrocarbon mixtures, the results described make the prediction of equilibrium coefficients possible, even for the most delicate separation. In the presence of polar constituents, the experimental data for the liquid-liquid and liquid-vapor equilibrium of binary and ternary mixtures can be simultaneously correlaten so as to simulate and optimize azeotropic or extractive distillations. Under high pressure and especially in the immediate vicinityof the critical point, the choice of an equation of state leads ta a unit treatment of the phases present and, in particular, makes it possible to predict the location of critical points in hydrocarbon

  1. Use of microalgae to recycle nutrients in aqueous phase derived from hydrothermal liquefaction process.

    Science.gov (United States)

    Leng, Lijian; Li, Jun; Wen, Zhiyou; Zhou, Wenguang

    2018-05-01

    Hydrothermal liquefaction (HTL) of microalgae biomass generates an aqueous phase (AP) byproduct with limited energy value. Recycling the AP solution as a source of nutrients for microalgae cultivation provides an opportunity for a cost-effective production of HTL based biofuel and algal biomass feedstock for HTL, allowing a closed-loop biofuel production in microalgae HTL biofuel system. This paper aims to provide a comprehensive overview of characteristics of AP and its nutrients recycling for algae production. Inhibitory effects resulted from the toxic compounds in AP and alleviation strategies are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Toroidal Extrap Equilibria

    International Nuclear Information System (INIS)

    Scheffel, J.

    1982-04-01

    Ideal MHD-equilibria for the toroidal EXTRAP configuration have been computed with an equilibrium code. The free-boundary prob- lem is solved by using the condition that the current density is proportional to r on a flux surface. It is found that the toroidal Z-pinch, initially induced in the central zero-field region of a transverse octupole field, drifts radially outwards producing an inverse -D shaped cross-section. The plasma current of this high- beta equilibrium may be increased if the plasma is pushed back by altering the external confining magnetic field as demonstrated. (Author)

  3. Resurrecting Equilibria Through Cycles

    DEFF Research Database (Denmark)

    Barnett, Richard C.; Bhattacharya, Joydeep; Bunzel, Helle

    equilibria because they asymptotically violate some economic restriction of the model. The literature has always ruled out such paths. This paper studies a pure-exchange monetary overlapping generations economy in which real balances cycle forever between momentary equilibrium points. The novelty is to show...... that segments of the offer curve that have been previously ignored, can in fact be used to produce asymptotically valid cyclical paths. Indeed, a cycle can bestow dynamic validity on momentary equilibrium points that had erstwhile been classified as dynamically invalid....

  4. Formation of the second organic phase during uranyl nitrate extraction from aqueous solution by 30% tributylphosphate solution in paraffin

    International Nuclear Information System (INIS)

    Yhrkin, V.G.

    1996-01-01

    For extraction systems aqueous solution of uranyl nitrate-30% solution of tributylphosphate in individual paraffins from C 13 to C 17 the influence of the second organic phase of uranyl nitrate concentration in aqueous and organic phases, the length of hydrocarbon chain of paraffin hydrocarbon and temperature from 25 to 50 deg C on formation conditions has been defected. A special method of achieving the conditions of organic phase stratification from three-phase region, involving definition of equilibrium phases composition by density and refractive index, has been elaborated for more precise definition of organic phase homogeneity region. It has been revealed that without addition of nitric acid to uranyl nitrate solution the organic phase homogeneity limits can be achieved solely on paraffins C 15 , C 16 and C 17 and only under conditions similar to equeous phase saturation in terms of uranyl nitrate. 16 refs., 2 figs

  5. Tritium distribution ratios between the 30 % tributyl phosphate(TBP)-normal dodecane(nDD) organic phase and uranyl nitrate-nitric acid aqueous phase

    International Nuclear Information System (INIS)

    Fujine, Sachio; Uchiyama, Gunzou; Sugikawa, Susumu; Maeda, Mitsuru; Tsujino, Takeshi.

    1989-10-01

    Tritium distribution ratios between the organic and aqueous phases were measured for the system of 30 % tributyl phosphate(TBP)-normal dodecane(nDD)/uranyl nitrate-nitric acid water. It was confirmed that tritium is extracted by TBP into the organic phase in both chemical forms of tritiated water (HTO) and tritiated nitric acid (TNO 3 ). The value of tritium distribution ratio ranged from 0.002 to 0.005 for the conditions of 0-6 mol/L nitric acid, 0.5-800 mCi/L tritium in aqueous phase, and 0-125 g-U/L uranium in organic phase. Isotopic distribution coefficient of tritium between the organic and aqueous phases was observed to be about 0.95. (author)

  6. The distribution of Th(NO3)4, UO2(NO3)2 and HNO3 between an aqueous phase and an organic tributyl phosphate phase

    International Nuclear Information System (INIS)

    Nakashima, T.; Zimmer, E.

    1984-05-01

    The distribution of Th(NO 3 ) 4 , UO 2 (NO 3 ) 2 and HNO 3 between an aqueous phase and an organic phase, consisting of 30 Vol.% tributyl phosphate in dodecane, has been experimentally investigated. About 120 distribution data have been determined in the concentration ranges that can be seen in the THOREX process for reprocessing spent thorium bearing fuel. Based on the experimental data, two computer programs have been developed which make possible interpolations and, to some extent, extrapolations. With model 1, concentrations in the organic phase can be calculated if that in the aqueous phase are known. With model 2, concentrations in the aqueous phase can be calculated vice versa. Besides the description of the calculation models, a large body of calculated data can be found in this report. In a addition, a calculation mode is presented that makes possible the calculation of distribution data for very low thorium concentrations. (orig.) [de

  7. Institutions, Equilibria and Efficiency

    DEFF Research Database (Denmark)

    Competition and efficiency is at the core of economic theory. This volume collects papers of leading scholars, which extend the conventional general equilibrium model in important ways. Efficiency and price regulation are studied when markets are incomplete and existence of equilibria in such set......Competition and efficiency is at the core of economic theory. This volume collects papers of leading scholars, which extend the conventional general equilibrium model in important ways. Efficiency and price regulation are studied when markets are incomplete and existence of equilibria...... in such settings is proven under very general preference assumptions. The model is extended to include geographical location choice, a commodity space incorporating manufacturing imprecision and preferences for club-membership, schools and firms. Inefficiencies arising from household externalities or group...... membership are evaluated. Core equivalence is shown for bargaining economies. The theory of risk aversion is extended and the relation between risk taking and wealth is experimentally investigated. Other topics include: determinacy in OLG with cash-in-advance constraints, income distribution and democracy...

  8. Aqueous two-phase systems for extractive enzymatic hydrolysis of biomass

    DEFF Research Database (Denmark)

    Bussamra, Bianca Consorti; Azzoni, Sindelia Freitas; Mussatto, Solange I.

    and enzymes, phase diagrams and volumetric ratios. The results of this project will make possible to design a process that enables high sugar concentration during the hydrolysis reaction, overcoming one of the biggest drawbacks regarding the production of second-generation ethanol: the enzymatic inhibition...... optimal aqueous two-phase systems for the separation of sugars and enzymes, which allow the development of an improved second-generation ethanol process.......Sugars derived from lignocellulosic materials are the main carbon sources in bio-based processes aiming to produce renewable fuels and chemicals. One of the major drawbacks during enzymatic hydrolysis of lignocellulosic materials to obtainsugars is the inhibition of enzymes by reaction products...

  9. Biosurfactant production by Pseudomonas sp. and its role in aqueous phase partitioning and biodegradation of chlorpyrifos.

    Science.gov (United States)

    Singh, P B; Sharma, S; Saini, H S; Chadha, B S

    2009-09-01

    To study the effect of biosurfactant on aqueous phase solubility and biodegradation of chlorpyrifos. A Pseudomonas sp. (ChlD), isolated from agricultural soil by enrichment culture technique in the presence of chlorpyrifos, was capable of producing biosurfactant (rhamnolipids) and degrading chlorpyrifos (0.01 g l(-1)). The partially purified rhamnolipid biosurfactant preparation, having a CMC of 0.2 g l(-1), was evaluated for its ability to enhance aqueous phase partitioning and degradation of chlorpyrifos (0.01 g l(-1)) by ChlD strain. The best degradation efficiency was observed at 0.1 g l(-1) supplement of biosurfactant, as validated by GC and HPLC studies. The addition of biosurfactant at 0.1 g l(-1) resulted in more than 98% degradation of chlorpyrifos when compared to 84% in the absence of biosurfactant after 120-h incubation. This first report, to the best of our knowledge, on enhanced degradation of chlorpyrifos in the presence of biosurfactant(s), would help in developing bioremediation protocols to counter accumulation of organophosphates to toxic/carcinogenic levels in environment.

  10. Mechanistic insights into aqueous phase propanol dehydration in H-ZSM-5 zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Donghai [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate & Institute for Integrated Catalysis, Richland WA 99352; Lercher, Johannes A. [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate & Institute for Integrated Catalysis, Richland WA 99352; Dept. of Chemistry and Catalysis Research Institute, TU München, Lichtenbergstrasse 4 Garching 85748 Germany

    2016-10-06

    Aqueous phase dehydration of 1-propanol over H-ZSM-5 zeolite was investigated using density functional theory (DFT) calculations. The water molecules in the zeolite pores prefer to aggregate via the hydrogen bonding network and be protonated at the Brønsted acidic sites (BAS). Two typical configurations, i.e., dispersed and clustered, of water molecules were identified by ab initio molecular dynamics simulation of the mimicking aqueous phase H-ZSM-5 zeolite unit cell with 20 water molecules per unit cell. DFT calculated Gibbs free energies suggest that the dimeric propanol-propanol, the propanol-water complex, and the trimeric propanol-propanol-water are formed at high propanol concentrations, which provide a kinetically feasible dehydration reaction channel of 1-propanol to propene. However, calculation results also indicate that the propanol dehydration via the unimolecular mechanism becomes kinetically discouraged due to the enhanced stability of the protonated dimeric propanol and the protonated water cluster acting as the BAS site for alcohol dehydration reaction. This work was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. Computing time was granted by the grand challenge of computational catalysis of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). EMSL is a national scientific user facility located at Pacific Northwest National Laboratory (PNNL) and sponsored by DOE’s Office of Biological and Environmental Research.

  11. Aqueous two-phase extraction as a platform in the biomanufacturing industry: economical and environmental sustainability.

    Science.gov (United States)

    Rosa, P A J; Azevedo, A M; Sommerfeld, S; Bäcker, W; Aires-Barros, M R

    2011-01-01

    The biotech industry is, nowadays, facing unparalleled challenges due to the enhanced demand for biotechnology-based human therapeutic products, such as monoclonal antibodies (mAbs). This has led companies to improve substantially their upstream processes, with the yield of monoclonals increasing to titers never seen before. The downstream processes have, however, been overlooked, leading to a production bottleneck. Although chromatography remains the workhorse of most purification processes, several limitations, such as low capacity, scale-related packing problems, low chemical and proteolytic stability and resins' high cost, have arisen. Aqueous two-phase extraction (ATPE) has been successfully revisited as a valuable alternative for the capture of antibodies. One of the important remaining questions for this technology to be adopted by the biotech industries is, now, how it compares to the currently established platforms in terms of costs and environmental impact. In this report, the economical and environmental sustainability of the aqueous two-phase extraction process is evaluated and compared to the currently established protein A affinity chromatography. Accordingly, the ATPE process was shown to be considerably advantageous in terms of process economics, especially when processing high titer cell culture supernatants. This alternative process is able to purify continuously the same amount of mAbs reducing the annual operating costs from 14.4 to 8.5 million (US$/kg) when cell culture supernatants with mAb titers higher than 2.5 g/L are processed. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Review of Liquidus Surface and Phase Equilibria in the TiO2-SiO2-Al2O3-MgO-CaO Slag System at PO2 Applicable in Fluxed Titaniferous Magnetite Smelting

    Science.gov (United States)

    Goso, Xolisa; Nell, Johannes; Petersen, Jochen

    The current liquidus surface and phase equilibria established in air for fluxed titaniferous magnetite (titanomagnetite) slags conforming to a composition of 37.19% TiO2, 19.69% SiO2, 13.12% Al2O3, and 30.00% of various ratios of CaO+MgO were reviewed at applicable PO2 using FactSage simulation and phase composition of a real plant titanomagnetite slag. The testwork included the incorporation into FactSage of a private MgTi2O5-Al2TiO5 pseudobrookite solution model. The results of the investigation showed that the liquidus surface and Ti3+/ Ti4+ mass fraction ratio increased with decreasing the PO2, At low PO2, perovskite crystallizes as a primary phase at high CaO content. The spinel solution, i.e. (Mg)(Al,Ti)O4, generally crystallizes as the primary phase at high MgO contents, though it is replaced by MgTi2O5-Al2TiO5 solution at PO2 of 10-10 atm to 10-15 atm. An intermediate equilibrium phase diagram established at PO2 of 10-16 atm is proposed. This phase diagram does not show the observed primary phase crystallization competition, however, the phase composition of a real titanomagnetite slag produced by Evraz Highveld Steel and Vanadium Corporation in South Africa does show primary phase crystallization competition between (Mg)(Al,Ti)2O4 and MgTi2O5-Al2TiO5. Smelting involving such slags is likely conducted around the transition PO2, i.e. PO2 of about 10-16 atm. Complex modelling with MgTi2O5, Al2TiO5 and Ti3O5 end members and experiments are underway to verify and update the intermediate phase diagram.

  13. Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H2O2, O3 and iron catalysis

    Directory of Open Access Journals (Sweden)

    J. N. Crowley

    2012-01-01

    Full Text Available The oxidation of SO2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents laboratory measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H2O2, O3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34S/32S during the gas-phase reaction is αOH = (1.0089±0.0007−((4±5×10−5 T(°C. The measured fractionation factor for 34S/32S during aqueous oxidation by H2O2 or O3 is αaq = (1.0167±0.0019−((8.7±3.5 ×10−5T(°C. The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilibria of S(IV in solution, which is the reason that there is no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.9894±0.0043 at 19 °C for 34S/32S. Fractionation was mass-dependent with regards to 33S/32S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. The results presented in this study will be particularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxidation pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone.

  14. Treatment of aqueous phase of bio-oil by granular activated carbon and evaluation of biogas production.

    Science.gov (United States)

    Shanmugam, Saravanan R; Adhikari, Sushil; Wang, Zhouhang; Shakya, Rajdeep

    2017-01-01

    Hydrothermal liquefaction of wet biomass such as algae is a promising thermochemical process for the production of bio-oil. Bio-oil aqueous phase generated during liquefaction process is rich in complex organics and can be utilized for biogas production following its pre-treatment with granular activated carbon. In our study, use of 30% activated carbon resulted in higher chemical oxygen demand (COD) reduction (53±0.3%) from aqueous phase. Higher CH 4 production (84±12mL/gCOD) was also observed in 30% carbon-treated aqueous phase fed cultures, whereas only 32±6mLCH 4 /gCOD was observed in control (non-carbon treated) cultures. The results from this study indicate that almost 67±0.3% initial COD of aqueous phase can be reduced using a combination of both carbon treatment and biogas production. This study shows that aqueous phase can be utilized for CH 4 production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Improving the treatment of non-aqueous phase TCE in low permeability zones with permanganate

    Energy Technology Data Exchange (ETDEWEB)

    Chokejaroenrat, Chanat, E-mail: chanat@sut.ac.th [Department of Civil Engineering, University of Nebraska, Lincoln, NE 68588-0531 (United States); School of Environmental Engineering, Institute of Engineering, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Comfort, Steve, E-mail: scomfort1@unl.edu [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States); Sakulthaew, Chainarong, E-mail: cvtcns@ku.ac.th [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States); Department of Veterinary Technology, Kasetsart University, Bangkok 10900 (Thailand); Dvorak, Bruce, E-mail: bdvorak1@unl.edu [Department of Civil Engineering, University of Nebraska, Lincoln, NE 68588-0531 (United States)

    2014-03-01

    Graphical abstract: - Highlights: • Transport experiments used transmissive and low permeability zones (LPZs). • {sup 14}C-labeled TCE was used to quantify oxidation of DNAPL in LPZs by permanganate. • Stabilization aids prevented MnO{sub 2} rind formation. • DNAPL oxidation improved when xanthan and stabilization aids were used. - Abstract: Treating dense non-aqueous phase liquids (DNAPLs) embedded in low permeability zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate (MnO{sub 4}{sup −}) into LPZs to treat high concentrations of TCE. This was accomplished by conducting transport experiments that quantified the penetration of various permanganate flooding solutions into a LPZ that was spiked with non-aqueous phase {sup 14}C-TCE. The treatments we evaluated included permanganate paired with: (i) a shear-thinning polymer (xanthan); (ii) stabilization aids that minimized MnO{sub 2} rind formation and (iii) a phase-transfer catalyst. In addition, we quantified the ability of these flooding solutions to improve TCE destruction under batch conditions by developing miniature LPZ cylinders that were spiked with {sup 14}C-TCE. Transport experiments showed that MnO{sub 4}{sup −} alone was inefficient in penetrating the LPZ and reacting with non-aqueous phase TCE, due to a distinct and large MnO{sub 2} rind that inhibited the TCE from further oxidant contact. By including xanthan with MnO{sub 4}{sup −}, the sweeping efficiency increased (90%) but rind formation was still evident. By including the stabilization aid, sodium hexametaphosphate (SHMP) with xanthan, permanganate penetrated 100% of the LPZ, no rind was observed, and the percentage of TCE oxidized increased. Batch experiments using LPZ cylinders allowed longer contact times between the flooding solutions and the DNAPL and results showed that SHMP + MnO{sub 4}{sup −} improved TCE destruction by

  16. Improving the treatment of non-aqueous phase TCE in low permeability zones with permanganate

    International Nuclear Information System (INIS)

    Chokejaroenrat, Chanat; Comfort, Steve; Sakulthaew, Chainarong; Dvorak, Bruce

    2014-01-01

    Graphical abstract: - Highlights: • Transport experiments used transmissive and low permeability zones (LPZs). • 14 C-labeled TCE was used to quantify oxidation of DNAPL in LPZs by permanganate. • Stabilization aids prevented MnO 2 rind formation. • DNAPL oxidation improved when xanthan and stabilization aids were used. - Abstract: Treating dense non-aqueous phase liquids (DNAPLs) embedded in low permeability zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate (MnO 4 − ) into LPZs to treat high concentrations of TCE. This was accomplished by conducting transport experiments that quantified the penetration of various permanganate flooding solutions into a LPZ that was spiked with non-aqueous phase 14 C-TCE. The treatments we evaluated included permanganate paired with: (i) a shear-thinning polymer (xanthan); (ii) stabilization aids that minimized MnO 2 rind formation and (iii) a phase-transfer catalyst. In addition, we quantified the ability of these flooding solutions to improve TCE destruction under batch conditions by developing miniature LPZ cylinders that were spiked with 14 C-TCE. Transport experiments showed that MnO 4 − alone was inefficient in penetrating the LPZ and reacting with non-aqueous phase TCE, due to a distinct and large MnO 2 rind that inhibited the TCE from further oxidant contact. By including xanthan with MnO 4 − , the sweeping efficiency increased (90%) but rind formation was still evident. By including the stabilization aid, sodium hexametaphosphate (SHMP) with xanthan, permanganate penetrated 100% of the LPZ, no rind was observed, and the percentage of TCE oxidized increased. Batch experiments using LPZ cylinders allowed longer contact times between the flooding solutions and the DNAPL and results showed that SHMP + MnO 4 − improved TCE destruction by ∼16% over MnO 4 − alone (56.5% vs. 40.1%). These results support

  17. Kinetics, Mechanism, and Secondary Organic Aerosol Yield of Aqueous Phase Photo-oxidation of α-Pinene Oxidation Products.

    Science.gov (United States)

    Aljawhary, Dana; Zhao, Ran; Lee, Alex K Y; Wang, Chen; Abbatt, Jonathan P D

    2016-03-10

    Formation of secondary organic aerosol (SOA) involves atmospheric oxidation of volatile organic compounds (VOCs), the majority of which are emitted from biogenic sources. Oxidation can occur not only in the gas-phase but also in atmospheric aqueous phases such as cloudwater and aerosol liquid water. This study explores for the first time the aqueous-phase OH oxidation chemistry of oxidation products of α-pinene, a major biogenic VOC species emitted to the atmosphere. The kinetics, reaction mechanisms, and formation of SOA compounds in the aqueous phase of two model compounds, cis-pinonic acid (PIN) and tricarballylic acid (TCA), were investigated in the laboratory; TCA was used as a surrogate for 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a known α-pinene oxidation product. Aerosol time-of-flight chemical ionization mass spectrometry (Aerosol-ToF-CIMS) was used to follow the kinetics and reaction mechanisms at the molecular level. Room-temperature second-order rate constants of PIN and TCA were determined to be 3.3 (± 0.5) × 10(9) and 3.1 (± 0.2) × 10(8) M(-1) s(-1), respectively, from which were estimated their condensed-phase atmospheric lifetimes. Aerosol-ToF-CIMS detected a large number of products leading to detailed reaction mechanisms for PIN and MBTCA. By monitoring the particle size distribution after drying, the amount of SOA material remaining in the particle phase was determined. An aqueous SOA yield of 40 to 60% was determined for PIN OH oxidation. Although recent laboratory studies have focused primarily on aqueous-phase processing of isoprene-related compounds, we demonstrate that aqueous formation of SOA materials also occurs from monoterpene oxidation products, thus representing an additional source of biogenically driven aerosol formation.

  18. A green deep eutectic solvent-based aqueous two-phase system for protein extracting

    International Nuclear Information System (INIS)

    Xu, Kaijia; Wang, Yuzhi; Huang, Yanhua; Li, Na; Wen, Qian

    2015-01-01

    Highlights: • A strategy for the protein purification with a deep eutectic solvent(DES)-based aqueous two-phase system. • Choline chloride-glycerin DES was selected as the extraction solvent. • Bovine serum albumin and trypsin were used as the analytes. • Aggregation phenomenon was detected in the mechanism research. - Abstract: As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n = 3), 1.6057% (n = 3) and 1.6132% (n = 3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV–vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES–protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins

  19. Aqueous nitrite ion determination by selective reduction and gas phase nitric oxide chemiluminescence

    Science.gov (United States)

    Dunham, A. J.; Barkley, R. M.; Sievers, R. E.; Clarkson, T. W. (Principal Investigator)

    1995-01-01

    An improved method of flow injection analysis for aqueous nitrite ion exploits the sensitivity and selectivity of the nitric oxide (NO) chemilluminescence detector. Trace analysis of nitrite ion in a small sample (5-160 microL) is accomplished by conversion of nitrite ion to NO by aqueous iodide in acid. The resulting NO is transported to the gas phase through a semipermeable membrane and subsequently detected by monitoring the photoemission of the reaction between NO and ozone (O3). Chemiluminescence detection is selective for measurement of NO, and, since the detection occurs in the gas-phase, neither sample coloration nor turbidity interfere. The detection limit for a 100-microL sample is 0.04 ppb of nitrite ion. The precision at the 10 ppb level is 2% relative standard deviation, and 60-180 samples can be analyzed per hour. Samples of human saliva and food extracts were analyzed; the results from a standard colorimetric measurement are compared with those from the new chemiluminescence method in order to further validate the latter method. A high degree of selectivity is obtained due to the three discriminating steps in the process: (1) the nitrite ion to NO conversion conditions are virtually specific for nitrite ion, (2) only volatile products of the conversion will be swept to the gas phase (avoiding turbidity or color in spectrophotometric methods), and (3) the NO chemiluminescence detector selectively detects the emission from the NO + O3 reaction. The method is free of interferences, offers detection limits of low parts per billion of nitrite ion, and allows the analysis of up to 180 microL-sized samples per hour, with little sample preparation and no chromatographic separation. Much smaller samples can be analyzed by this method than in previously reported batch analysis methods, which typically require 5 mL or more of sample and often need chromatographic separations as well.

  20. Influence of aqueous phase on electrochemical biocorrosion tests in diesel/water systems

    Energy Technology Data Exchange (ETDEWEB)

    Bento, F.M. [Dept. of Soils, Faculty of Agronomy, UFRGS, 7712 Bento Goncalves Avenue, CEP: 91540-001, POA, RS (Brazil); Englert, G.E.; Muller, I.L. [Dept. of Metallurgy, Biocorrosion and Biofilms Lab, UFRGS, 99 Osvaldo Aranha Avenue s.615D, CEP: 90035-190, POA, RS (Brazil); Gaylarde, C.C. [Dept. of Biophisics, UFRGS POA, RS (Brazil)

    2004-08-01

    Storage tanks containing microbially contaminated diesel oil are susceptible to corrosion. This process may be evaluated electrochemically in the laboratory using simulated storage systems containing diesel oil and an aqueous phase. The simulated aqueous phase must supply mineral nutrients for microbial growth, together with adequate electrical conductivity, without, however, being too corrosive, so as to allow the aggressive nature of the microbial metabolites to be detected. In this investigation, microbial growth was measured in six electrically conductive media overlaid with metropolitan diesel oil containing an additive package. The microorganisms were the filamentous fungi, Hormoconis resinae, Paecilomyces variotii and Aspergillus fumigatus, the bacterium Bacillus subtilis and the yeast Candida silvicola, all previously isolated from contaminated diesel oil. After 60 days incubation with pure or mixed inocula of these microorganisms, pH, conductivity and viable microorganisms were measured. The electrochemical behaviour of carbon steel ASTM 283-93-C was determined in each of the six media (uninoculated) and in selected inoculated medium via measurements of open circuit potential and potentiostatic polarization curves. The uptake of phosphate (corrosion inhibitor), microbial growth, pH, conductivity and anodic and cathodic polarization curves were assessed in the water phase after 30 and 60 days of incubation with each single species Aspergillus fumigatus and Hormoconis resinae and with the consortium. The medium which proved most appropriate was Bushnell-Haas medium modified by the omission of chlorides, which allowed satisfactory microbial growth and had low aggressivity towards the steel. The performance of electrochemical tests in aerated, rather than deaerated, electrolyte solutions is suggested to be important to allow the detection of microbial influence on passive film formation and stability. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  1. Aqueous two-phase system purification for superoxide dismutase induced by menadione from Phanerochaete chrysosporium.

    Science.gov (United States)

    Kavakcıoğlu, Berna; Tongul, Burcu; Tarhan, Leman

    2017-03-01

    In the present work, the partitioning behavior of menadione-induced superoxide dismutase (SOD; EC 1.15.1.1), an antioxidant enzyme that has various applications in the medical and cosmetic industries, from the white rot fungus Phanerochaete chrysosporium has been characterized on different types of aqueous two-phase systems (ATPSs) (poly(ethylene glycol)/polypropylene glycol (PEG/PPG)-dextran, PEG-salt and PPG-salt). PEG-salt combinations were found most optimal systems for the purification of SOD. The best partition conditions were found using the PEG-3350 24% and K 2 HPO 4 5% (w/w) with pH 7.0 at 25 °C. The partition coefficient of total SOD activity and total protein concentration observed in this system were 0.17 and 6.65, respectively, with the recovery percentage as 78.90% in the bottom phase and 13.17% in the top phase. The highest purification fold for SOD from P. chrysosporium was found as 6.04 in the bottom phase of PEG 3350%24 - K 2 HPO 4 %5 (w/w) system with pH 7.0. SOD purified from P. chrysosporium was determined to be a homodimer in its native state with a molecular weight of 60  ± 4 kDa. Consequently, simple and only one step PEG-salt ATPS system was developed for SOD purification from P. chrysosporium.

  2. Adsorption analysis equilibria and kinetics

    CERN Document Server

    Do, Duong D

    1998-01-01

    This book covers topics of equilibria and kinetics of adsorption in porous media. Fundamental equilibria and kinetics are dealt with for homogeneous as well as heterogeneous particles. Five chapters of the book deal with equilibria and eight chapters deal with kinetics. Single component as well as multicomponent systems are discussed. In kinetics analysis, we deal with the various mass transport processes and their interactions inside a porous particle. Conventional approaches as well as the new approach using Maxwell-Stefan equations are presented. Various methods to measure diffusivity, such

  3. Quantum equilibria for macroscopic systems

    International Nuclear Information System (INIS)

    Grib, A; Khrennikov, A; Parfionov, G; Starkov, K

    2006-01-01

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered

  4. Quantum equilibria for macroscopic systems

    Energy Technology Data Exchange (ETDEWEB)

    Grib, A [Department of Theoretical Physics and Astronomy, Russian State Pedagogical University, St. Petersburg (Russian Federation); Khrennikov, A [Centre for Mathematical Modelling in Physics and Cognitive Sciences Vaexjoe University (Sweden); Parfionov, G [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation); Starkov, K [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation)

    2006-06-30

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered.

  5. Inverse plasma equilibria

    International Nuclear Information System (INIS)

    Hicks, H.R.; Dory, R.A.; Holmes, J.A.

    1983-01-01

    We illustrate in some detail a 2D inverse-equilibrium solver that was constructed to analyze tokamak configurations and stellarators (the latter in the context of the average method). To ensure that the method is suitable not only to determine equilibria, but also to provide appropriately represented data for existing stability codes, it is important to be able to control the Jacobian, tilde J is identical to delta(R,Z)/delta(rho, theta). The form chosen is tilde J = J 0 (rho)R/sup l/rho where rho is a flux surface label, and l is an integer. The initial implementation is for a fixed conducting-wall boundary, but the technique can be extended to a free-boundary model

  6. Experimental determination and thermodynamic modeling of phase equilibrium and protein partitioning in aqueous two-phase systems containing biodegradable salts

    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.

  7. Fundamental thermochemical properties of amino acids: gas-phase and aqueous acidities and gas-phase heats of formation.

    Science.gov (United States)

    Stover, Michele L; Jackson, Virgil E; Matus, Myrna H; Adams, Margaret A; Cassady, Carolyn J; Dixon, David A

    2012-03-08

    The gas-phase acidities of the 20 L-amino acids have been predicted at the composite G3(MP2) level. A broad range of structures of the neutral and anion were studied to determine the lowest energy conformer. Excellent agreement is found with the available experimental gas-phase deprotonation enthalpies, and the calculated values are within experimental error. We predict that tyrosine is deprotonated at the CO(2)H site. Cysteine is predicted to be deprotonated at the SH but the proton on the CO(2)H is shared with the S(-) site. Self-consistent reaction field (SCRF) calculations with the COSMO parametrization were used to predict the pK(a)'s of the non-zwitterion form in aqueous solution. The differences in the non-zwitterion pK(a) values were used to estimate the free energy difference between the zwitterion and nonzwitterion forms in solution. The heats of formation of the neutral compounds were calculated from atomization energies and isodesmic reactions to provide the first reliable set of these values in the gas phase. Further calculations were performed on five rare amino acids to predict their heats of formation, acidities, and pK(a) values.

  8. Prediction of Gas Hydrate Formation Conditions in Aqueous Solutions of Single and Mixed Electrolytes

    DEFF Research Database (Denmark)

    Zuo, You-Xiang; Stenby, Erling Halfdan

    1997-01-01

    In this paper, the extended Patel-Teja equation of state was modified to describe non-ideality of the liquid phase containing water and electrolytes accurately. The modified Patel-Teja equation of state (MPT EOS) was utilized to develop a predictive method for gas hydrate equilibria. The new method...... employs the Barkan and Sheinin hydrate model for the description of the hydrate phase, the original Patel-Teja equation of state for the vapor phase fugacities, and the MPT EOS (instead of the activity coefficient model) for the activity of water in the aqueous phase. The new method has succesfully...

  9. Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop

    Energy Technology Data Exchange (ETDEWEB)

    He Yi [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)]. E-mail: yhe@jjay.cuny.edu; Vargas, Angelica [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States); Kang, Youn-Jung [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)

    2007-04-25

    This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H{sub 3}PO{sub 4} drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 {mu}g L{sup -1}, repeatability of the extraction (R.S.D. < 5%, n = 6), and low detection limits (0.3 {mu}g L{sup -1} for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples.

  10. POLYELECTROLYTE MULTILAYER STAMPING IN AQUEOUS PHASE AND NON-CONTACT MODE

    Science.gov (United States)

    Mehrotra, Sumit; Lee, Ilsoon; Liu, Chun; Chan, Christina

    2011-01-01

    Polyelectrolyte multilayer (PEM) transfer printing has been previously achieved by stamping under dry conditions. Here, we show for the first time, that PEM can be transferred from a stamp to the base substrate under aqueous conditions whereby the two surfaces are in a non-contact mode. Degradable multilayers of (PAA/PEG)10.5 followed by non-degradable multilayers of (PDAC/SPS)80.5 were fabricated under acidic pH conditions on either PDMS or glass (stamp), and subsequently transferred over top of another multilayer prepared on a different substrate (base substrate), with a spacing of ~ 200 μm between the stamping surface and the base substrate. This multilayer transfer was performed under physiological pH conditions. This process is referred to herein as non-contact, aqueous-phase multilayer (NAM) transfer. NAM transfer can be useful for applications such as fabricating three-dimensional (3-D) cellular scaffolds. We attempted to create a 3-D cellular scaffold using NAM transfer, and characterized the scaffolds with conventional and fluorescence microscopy. PMID:21860540

  11. Adsorptive removal of phenol from aqueous phase by using a porous acrylic ester polymer

    International Nuclear Information System (INIS)

    Pan Bingjun; Pan Bingcai; Zhang Weiming; Zhang Qingrui; Zhang Quanxing; Zheng Shourong

    2008-01-01

    The removal of phenol from aqueous solution was examined by using a porous acrylic ester polymer (Amberlite XAD-7) as an adsorbent. Favorable phenol adsorption was observed at acidic solution pH and further increase of solution pH results in a marked decrease of adsorption capacity, and the coexisting inorganic salt NaCl exerts positive effect on the adsorption process. Adsorption isotherms of phenol were linearly correlated and found to be well represented by either the Langmuir or Freundlich isotherm model. Thermodynamic parameters such as changes in the enthalpy (ΔH), entropy (ΔS) and free energy (ΔG) indicate that phenol adsorption onto XAD-7 is an exothermic and spontaneous process in nature, and lower ambient temperature results in more favorable adsorption. Kinetic experiments at different initial solute concentrations were investigated and the pseudo-second-order kinetic model was successfully represented the kinetic data. Additionally, the column adsorption result showed that a complete removal of phenol from aqueous phase can be achieved by XAD-7 beads and the exhausted adsorbent was amenable to an entire regeneration by using ethanol as the regenerant. More interestingly, relatively more volume of hot water in place of ethanol can also achieve a similar result for repeated use of the adsorbent

  12. Dysprosium separation from aqueous phase by non-dispersive solvent extraction employing hollow fibre membrane module

    International Nuclear Information System (INIS)

    Yadav, Kartikey K.; Singh, D.K.; Kain, V.

    2017-01-01

    Rare earth elements (REEs) consist of fourteen lanthanides and three elements which are Sc, Y and La resulting in total 17 REEs. In the last decade, these rare earths elements which have unique physical and chemical properties have been highly in demand for their application in almost all walks of life. Various methods such as ion exchange, precipitation and solvent extraction have been used to recover these elements from aqueous solutions. These traditional methods have some inherent disadvantages like handling of hazardous organic chemicals, ineffectiveness to recover a very low concentration of contaminated source etc. In this regard, an important method i.e. liquid membrane offers separation scheme; which combines the characteristics, of solvent extraction and solid membrane separation, to overcome the disadvantages of conventional techniques. Various experiments were carried out to evaluate the effect of feed acidity, metal ion concentration, carrier concentration, feed composition, flow rates and phase ratio on the transport of rare earths metal ions across the membrane

  13. Aqueous phase complexation of Cm(III) and Cf(III) with ionizable macrocyclic ligands

    International Nuclear Information System (INIS)

    Manchanda, V.K.; Mohapatra, P.K.

    1995-01-01

    Complexation behaviour of Cm(III) and Cf(III) with 1,7-diaza-4,10,13-trioxacyclopentadecane-N,N'-diacetic acid (K21DA), 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N'-diacetic acid (K22DA) and ethylene diamine N,N'- diacetic acid (EDDA) has been investigated using dinonyl naphthalene sulphonic acid (DNNS), in tetramethyl ammonium form as liquid cation exchanger. The aqueous phase complex formation constants are computed from the distribution data. Though larger complex formation constants are observed with K21DA as well as K22DA compared to those with the acyclic analog EDDA, no size correlation is observed. (author). 5 refs., 1 tab

  14. Elementary steps and reaction pathways in the aqueous phase alkylation of phenol with ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, Sebastian; Hintermeier, Peter H.; Olarte, Mariefel V.; Liu, Yue; Baráth, Eszter; Lercher, Johannes A.

    2017-08-01

    The hydronium ion normalized reaction rate in aqueous phase alkylation of phenol with ethanol on H-MFI zeolites increases with decreasing concentration of acid sites. Higher rates are caused by higher concentrations of phenol in the zeolite pores, as the concentration of hydronium ions generated by zeolite Brønsted acid sites decreases. Considering the different concentrations of reacting species it is shown that the intrinsic rate constant for alkylation is independent of the concentration of hydronium ions in the zeolite pores. Alkylation at the aromatic ring of phenol and of toluene as well as O-alkylation of phenol have the same activation energy, 104 ± 5 kJ/mol. This is energetic barrier to form the ethyl carbenium ion from ethanol associated to the hydronium ion. Thus, in both the reaction pathways the catalyst involves a carbenium ion, which forms a bond to a nucleophilic oxygen (ether formation) or carbon (alkylation).

  15. Jump conditions in transonic equilibria

    International Nuclear Information System (INIS)

    Guazzotto, L.; Betti, R.; Jardin, S. C.

    2013-01-01

    In the present paper, the numerical calculation of transonic equilibria, first introduced with the FLOW code in Guazzotto et al.[Phys. Plasmas 11, 604 (2004)], is critically reviewed. In particular, the necessity and effect of imposing explicit jump conditions at the transonic discontinuity are investigated. It is found that “standard” (low-β, large aspect ratio) transonic equilibria satisfy the correct jump condition with very good approximation even if the jump condition is not explicitly imposed. On the other hand, it is also found that high-β, low aspect ratio equilibria require the correct jump condition to be explicitly imposed. Various numerical approaches are described to modify FLOW to include the jump condition. It is proved that the new methods converge to the correct solution even in extreme cases of very large β, while they agree with the results obtained with the old implementation of FLOW in lower-β equilibria.

  16. Pierce instability and bifurcating equilibria

    International Nuclear Information System (INIS)

    Godfrey, B.B.

    1981-01-01

    The report investigates the connection between equilibrium bifurcations and occurrence of the Pierce instability. Electrons flowing from one ground plane to a second through an ion background possess a countable infinity of static equilibria, of which only one is uniform and force-free. Degeneracy of the uniform and simplest non-uniform equilibria at a certain ground plan separation marks the onset of the Pierce instability, based on a newly derived dispersion relation appropriate to all the equilibria. For large ground plane separations the uniform equilibrium is unstable and the non-uniform equilibrium is stable, the reverse of their stability properties at small separations. Onset of the Pierce instability at the first bifurcation of equilibria persists in more complicated geometries, providing a general criterion for marginal stability. It seems probable that bifurcation analysis can be a useful tool in the overall study of stable beam generation in diodes and transport in finite cavities

  17. Supercooling of aqueous dimethylsulfoxide solution at normal and high pressures: Evidence for the coexistence of phase-separated aqueous dimethylsulfoxide solutions of different water structures

    Science.gov (United States)

    Kanno, H.; Kajiwara, K.; Miyata, K.

    2010-05-01

    Supercooling behavior of aqueous dimethylsulfoxide (DMSO) solution was investigated as a function of DMSO concentration and at high pressures. A linear relationship was observed for TH (homogeneous ice nucleation temperature) and Tm (melting temperature) for the supercooling of aqueous DMSO solution at normal pressure. Analysis of the DTA (differential thermal analysis) traces for homogeneous ice crystallization in the bottom region of the TH curve for a DMSO solution of R =20 (R: moles of water/moles of DMSO) at high pressures supported the contention that the second critical point (SCP) of liquid water should exist at Pc2=˜200 MPa and at Tc2pressure of SCP, Tc2: temperature of SCP). The presence of two TH peaks for DMSO solutions (R =15, 12, and 10) suggests that phase separation occurs in aqueous DMSO solution (R ≤15) at high pressures and low temperatures (pressure dependence of the two TH curves for DMSO solutions of R =10 and 12 indicates that the two phase-separated components in the DMSO solution of R =10 have different liquid water structures [LDL-like and HDL-like structures (LDL: low-density liquid water, HDL: high-density liquid water)] in the pressure range of 120-230 MPa.

  18. [DNA complexes, formed on aqueous phase surfaces: new planar polymeric and composite nanostructures].

    Science.gov (United States)

    Antipina, M N; Gaĭnutdinov, R V; Rakhnianskaia, A A; Sergeev-Cherenkov, A N; Tolstikhina, A L; Iurova, T V; Kislov, V V; Khomutov, G B

    2003-01-01

    The formation of DNA complexes with Langmuir monolayers of the cationic lipid octadecylamine (ODA) and the new amphiphilic polycation poly-4-vinylpyridine with 16% of cetylpyridinium groups (PVP-16) on the surface of an aqueous solution of native DNA of low ionic strength was studied. Topographic images of Langmuir-Blodgett films of DNA/ODA and DNA/PVP-16 complexes applied to micaceous substrates were investigated by the method of atomic force microscopy. It was found that films of the amphiphilic polycation have an ordered planar polycrystalline structure. The morphology of planar DNA complexes with the amphiphilic cation substantially depended on the incubation time and the phase state of the monolayer on the surface of the aqueous DNA solution. Complex structures and individual DNA molecules were observed on the surface of the amphiphilic monolayer. Along with quasi-linear individual bound DNA molecules, characteristic extended net-like structures and quasi-circular toroidal condensed conformations of planar DNA complexes were detected. Mono- and multilayer films of DNA/PVP-16 complexes were used as templates and nanoreactors for the synthesis of inorganic nanostructures via the binding of metal cations from the solution and subsequent generation of the inorganic phase. As a result, ultrathin polymeric composite films with integrated DNA building blocks and quasi-linear arrays of inorganic semiconductor (CdS) and iron oxide nanoparticles and nanowires were obtained. The nanostructures obtained were characterized by scanning probe microscopy and transmission electron microscopy techniques. The methods developed are promising for investigating the mechanisms of structural organization and transformation in DNA and polyelectrolyte complexes at the gas-liquid interface and for the design of new extremely thin highly ordered planar polymeric and composite materials, films, and coatings with controlled ultrastructure for applications in nanoelectronics and

  19. The impact of ionic liquid fluorinated moieties on their thermophysical properties and aqueous phase behaviour.

    Science.gov (United States)

    Neves, Catarina M S S; Kurnia, Kiki A; Shimizu, Karina; Marrucho, Isabel M; Rebelo, Luís Paulo N; Coutinho, João A P; Freire, Mara G; Lopes, José N Canongia

    2014-10-21

    In this work, we demonstrate that the presence of fluorinated alkyl chains in Ionic Liquids (ILs) is highly relevant in terms of their thermophysical properties and aqueous phase behaviour. We have measured and compared the density and viscosity of pure 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, [C2C1im][FAP], with that of pure 1-ethyl-3-methylimidazolium hexafluorophosphate, [C2C1im][PF6], at atmospheric pressure and in the (288.15 to 363.15) K temperature range. The results show that the density of [C2C1im][PF6] is lower than that of [C2C1im][FAP], while the viscosity data reveal the opposite trend. The fluid phase behaviour of aqueous solutions of the two ILs was also evaluated under the same conditions and it was found that the mutual solubilities of [C2C1im][FAP] and water are substantially lower than those verified with [C2C1im][PF6]. The experimental data were lastly interpreted at a molecular level using Molecular Dynamics (MD) simulation results revealing that the interactions between the IL ions and the water molecules are mainly achieved via the six fluorine atoms of [PF6](-) and the three analogues in [FAP](-). The loss of three interaction centres when replacing [PF6](-) by [FAP](-), coupled with the bulkiness and relative inertness of the three perfluoroethyl groups, reduces its mutual solubility with water and also contributes to a lower viscosity displayed by the pure [FAP]-based IL as compared to that of the [PF6]-based compound.

  20. Characterisation and final disposal behaviour of theoria-based fuel kernels in aqueous phases

    International Nuclear Information System (INIS)

    Titov, M.

    2005-08-01

    Two high-temperature reactors (AVR and THTR) operated in Germany have produced about 1 million spent fuel elements. The nuclear fuel in these reactors consists mainly of thorium-uranium mixed oxides, but also pure uranium dioxide and carbide fuels were tested. One of the possible solutions of utilising spent HTR fuel is the direct disposal in deep geological formations. Under such circumstances, the properties of fuel kernels, and especially their leaching behaviour in aqueous phases, have to be investigated for safety assessments of the final repository. In the present work, unirradiated ThO 2 , (Th 0.906 ,U 0.094 )O 2 , (Th 0.834 ,U 0.166 )O 2 and UO 2 fuel kernels were investigated. The composition, crystal structure and surface of the kernels were investigated by traditional methods. Furthermore, a new method was developed for testing the mechanical properties of ceramic kernels. The method was successfully used for the examination of mechanical properties of oxide kernels and for monitoring their evolution during contact with aqueous phases. The leaching behaviour of thoria-based oxide kernels and powders was investigated in repository-relevant salt solutions, as well as in artificial leachates. The influence of different experimental parameters on the kernel leaching stability was investigated. It was shown that thoria-based fuel kernels possess high chemical stability and are indifferent to presence of oxidative and radiolytic species in solution. The dissolution rate of thoria-based materials is typically several orders of magnitude lower than of conventional UO 2 fuel kernels. The life time of a single intact (Th,U)O 2 kernel under aggressive conditions of salt repository was estimated as about hundred thousand years. The importance of grain boundary quality on the leaching stability was demonstrated. Numerical Monte Carlo simulations were performed in order to explain the results of leaching experiments. (orig.)

  1. Huaier Aqueous Extract Induces Hepatocellular Carcinoma Cells Arrest in S Phase via JNK Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Chengshuo Zhang

    2015-01-01

    Full Text Available Huaier aqueous extract, the main active constituent of Huaier proteoglycan, has antihepatocarcinoma activity in experimental and clinical settings. However, the potential and associated antihepatoma mechanisms of Huaier extract are not yet fully understood. Therefore, in this study, we aimed to elucidate the inhibitory proliferation effect of Huaier extract on apoptosis and cycle of HepG2 and Bel-7402 cells. Our data demonstrated that incubation with Huaier extract resulted in a marked decrease in cell viability dose-dependently. Flow cytometric analysis showed that a 48 h treatment of Huaier extract caused cell apoptosis. Typical apoptotic nucleus alterations were observed with fluorescence microscope after Hoechst staining. Immunoblot analysis further demonstrated that Huaier extract activated caspase 3 and PARP. Additionally, Huaier extract inhibited the activity of p-ERK, p-p38, and p-JNK in terms of MAPK. Furthermore, Huaier extract induced HCC cells arrest in S phase and decreased the cycle related protein expression of β-catenin and cyclin D1. Studies with JNK specific inhibitor, SP600125, showed that Huaier extract induced S phase arrest and decreased β-catenin and cyclin D1 expression via JNK signaling pathway. In conclusion, we verify that Huaier extract causes cell apoptosis and induces hepatocellular carcinoma cells arrest in S phase via JNK pathway, which advances our understanding on the molecular mechanisms of Huaier extract in hepatocarcinoma management.

  2. Aqueous phase transfer of InP/ZnS nanocrystals conserving fluorescence and high colloidal stability.

    Science.gov (United States)

    Tamang, Sudarsan; Beaune, Grégory; Texier, Isabelle; Reiss, Peter

    2011-12-27

    Small thiol-containing amino acids such as cysteine are appealing surface ligands for transferring semiconductor quantum dots (QDs) from organic solvents to the aqueous phase. They provide a compact hydrodynamic diameter and low nonspecific binding in biological environment. However, cysteine-capped QDs generally exhibit modest colloidal stability in water and their fluorescence quantum yield (QY) is significantly reduced as compared to organics. We demonstrate that during phase transfer the deprotonation of the thiol group by carefully adjusting the pH is of crucial importance for increasing the binding strength of cysteine to the QD surface. As a result, the colloidal stability of cysteine-capped InP/ZnS core/shell QDs is extended from less than one day to several months. The developed method is of very general character and can be used also with other hydrophilic thiols and various other types of QDs, e.g., CdSe/CdS/ZnS and CuInS(2)/ZnS QDs as well as CdSe and CdSe/CdS nanorods. We show that the observed decrease of QY upon phase transfer with cysteine is related to the generation of cysteine dimer, cystine. This side-reaction implies the formation of disulfide bonds, which efficiently trap photogenerated holes and inhibit radiative recombination. On the other hand, this process is not irreversible. By addition of an appropriate reducing agent, tris(2-carboxyethyl)phosphine hydrochloride (TCEP), the QY can be partially recovered. When TCEP is already added during the phase transfer, the QY of cysteine-capped InP/ZnS QDs can be maintained almost quantitatively. Finally, we show that penicillamine is a promising alternative to cysteine for the phase transfer of QDs, as it is much less prone to disulfide formation.

  3. Cheese whey valorisation: Production of valuable gaseous and liquid chemicals from lactose by aqueous phase reforming

    International Nuclear Information System (INIS)

    Remón, J.; Ruiz, J.; Oliva, M.; García, L.; Arauzo, J.

    2016-01-01

    Highlights: • Aqueous phase reforming: a promising strategy for cheese whey valorisation. • In-depth understanding of the effect of the operating conditions on the process. • Process optimisation for the selective production of valuable gas and liquid products. • High P, T, lactose concentration and spatial time favour gas production. • High T, low spatial time and the use of diluted solutions maximise liquids production. - Abstract: Cheese effluent management has become an important issue owing to its high biochemical oxygen demand and chemical oxygen demand values. Given this scenario, this work addresses the valorisation of lactose (the largest organic constituent of this waste) by aqueous phase reforming, analysing the influence of the most important operating variables (temperature, pressure, lactose concentration and mass of catalyst/lactose mass flow rate ratio) as well as optimising the process for the production of either gaseous or liquid value-added chemicals. The carbon converted into gas, liquid and solid products varied as follows: 5–41%, 33–97% and 0–59%, respectively. The gas phase was made up of a mixture of H_2 (8–58 vol.%), CO_2 (33–85 vol.%), CO (0–15 vol.%) and CH_4 (0–14 vol.%). The liquid phase consisted of a mixture of aldehydes: 0–11%, carboxylic acids: 0–22%, monohydric alcohols: 0–23%, polyhydric-alcohols: 0–48%, C3-ketones: 4–100%, C4-ketones: 0–18%, cyclic-ketones: 0–15% and furans: 0–85%. H_2 production is favoured at high pressure, elevated temperature, employing a high amount of catalyst and a concentrated lactose solution. Liquid production is preferential using diluted lactose solutions. At high pressure, the production of C3-ketones is preferential using a high temperature and a low amount of catalyst, while a medium temperature and a high amount of catalyst favours the production of furans. The production of alcohols is preferential using medium temperature and pressure and a low amount of

  4. Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: a kinetic study

    Science.gov (United States)

    Kroflič, Ana; Grgić, Irena

    2014-05-01

    It is well known that atmospheric aerosols play a crucial role in the Earth's climate and public health (Pöschl 2005). Despite a great effort invested in the studies of secondary organic aerosol (SOA) budget, composition, and its formation mechanisms, there is still a gap between field observations and atmospheric model predictions (Heald et al. 2005, Hallquist et al. 2009, and Lim et al. 2010). The insisting uncertainties surrounding SOA formation and aging thus gained an increasing interest in atmospheric aqueous phase chemistry; they call for more complex and time consuming studies at the environmentally relevant conditions allowing confident extrapolation to desired ambient conditions. In addition to the adverse health effects of atmospheric particulate matter (PM) as such, toxicity is also attributed to nitro-aromatic and other organic compounds which have already been detected in real aerosol samples (Traversi et al. 2009). Moreover, low-volatility aromatic derivatives are believed to form at least partly in the aerosol aqueous phase and not only in the gas phase from where they partition into water droplets (Ervens et al. 2011). Two nitro derivatives of biomass burning tracer guaiacol have recently been found in winter PM10 samples from the city of Ljubljana, Slovenia, and aqueous photonitration reaction was proposed as their possible production pathway (Kitanovski et al. 2012). In this study the kinetics of guaiacol nitration in aqueous solution was investigated in the presence of H2O2 and NO2¯ upon simulated solar irradiation (Xenon lamp, 300 W). During the experiment the DURAN® flask with the reaction mixture was held in the thermostated bath and thoroughly mixed. The reaction was monitored for 44 hours at different temperatures. Guaiacol and its main nitro-products (4-nitroguaiacol, 4-NG; 6-nitroguaiacol, 6-NG; and 4,6-dinitroguaiacol, 4,6-DNG) were quantified in every aliquot, taken from the reaction mixture, by use of high pressure liquid

  5. Adsorptive removal of phthalate ester (Di-ethyl phthalate) from aqueous phase by activated carbon: a kinetic study.

    Science.gov (United States)

    Venkata Mohan, S; Shailaja, S; Rama Krishna, M; Sarma, P N

    2007-07-19

    Adsorptive studies were carried out on Di-ethyl phthalate (DEP) removal from aqueous phase onto activated carbon. Batch sorption studies were performed and the results revealed that activated carbon demonstrated ability to adsorb DEP. Influence of varying experimental conditions such as DEP concentration, pH of aqueous solution, and dosage of adsorbent were investigated on the adsorption process. Sorption interaction of DEP onto activated carbon obeyed the pseudo second order rate equation. Experimental data showed good fit with both the Langmuir and Freundlich adsorption isotherm models. DEP sorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at acidic pH.

  6. [Phase transfer catalyzed bioconversion of penicillin G to 6-APA by immobilized penicillin acylase in recyclable aqueous two-phase systems with light/pH sensitive copolymers].

    Science.gov (United States)

    Jin, Ke-ming; Cao, Xue-jun; Su, Jin; Ma, Li; Zhuang, Ying-ping; Chu, Ju; Zhang, Si-liang

    2008-03-01

    Immobilized penicillin acylase was used for bioconversion of penicillin PG into 6-APA in aqueous two-phase systems consisting of a light-sensitive polymer PNBC and a pH-sensitive polymer PADB. Partition coefficients of 6-APA was found to be about 5.78 in the presence of 1% NaCl. Enzyme kinetics showed that the reaction reached equilibrium at roughly 7 h. The 6-APA mole yields were 85.3% (pH 7.8, 20 degrees C), with about 20% increment as compared with the reaction of single aqueous phase buffer. The partition coefficient of PG (Na) varied scarcely, while that of the product, 6-APA and phenylacetic acid (PA) significantly varied due to Donnan effect of the phase systems and hydrophobicity of the products. The variation of the partition coefficients of the products also affected the bioconversion yield of the products. In the aqueous two-phase systems, the substrate, PG, the products of 6-APA and PA were biased in the top phase, while immobilized penicillin acylase at completely partitioned at the bottom. The substrate and PG entered the bottom phase, where it was catalyzed into 6-APA and PA and entered the top phase. Inhibition of the substrate and products was removed to result in improvement of the product yield, and the immobilized enzyme showed higher efficiency than the immobilized cells and occupied smaller volume. Compared with the free enzyme, immobilized enzyme had greater stability, longer life-time, and was completely partitioned in the bottom phase and recycle. Bioconversion in two-phase systems using immobilized penicillin acylase showed outstanding advantage. The light-sensitive copolymer forming aqueous two-phase systems could be recovered by laser radiation at 488 nm or filtered 450 nm light, while pH-sensitive polymer PADB could be recovered at the isoelectric point (pH 4.1). The recovery of the two copolymers was between 95% and 99%.

  7. Collisionless current sheet equilibria

    Science.gov (United States)

    Neukirch, T.; Wilson, F.; Allanson, O.

    2018-01-01

    Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

  8. Sol-gel transitions and liquid crystal phase transitions in concentrated aqueous suspensions of colloidal gibbsite platelets

    NARCIS (Netherlands)

    Mourad, M.C.D.; Byelov, D.V.; Petukhov, A.V.; de Winter, D.A.M.; Verkleij, A.J.; Lekkerkerker, H.N.W.

    2009-01-01

    In this paper, we present a comprehensive study of the sol-gel transitions and liquid crystal phase transitions in aqueous suspensions of positively charged colloidal gibbsite platelets at pH 4-5 over a wide range of particle concentrations (50-600 g/L) and salt concentrations (10-4-10-1 M NaCl). A

  9. Highly selective bimetallic Pt-Cu/Mg(Al)O catalysts for the aqueous-phase reforming of glycerol

    NARCIS (Netherlands)

    Boga, D.A.; Oord, R.; Beale, A.M.; Chung, Y.M.; Bruijnincx, P.C.A.; Weckhuysen, B.M.

    2013-01-01

    Monometallic Pt and bimetallic Pt-Cu catalysts supported on Mg(Al)O mixed oxides, obtained by calcination of the corresponding layered double hydroxides (LDHs), were prepared and tested in the aqueous-phase reforming (APR) of glycerol. The effect of the Mg/Al ratio and calcination temperature of the

  10. Programme of research into the management and storage of radioactive waste. Aqueous phase transport through granitic rocks

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Green, A.

    1984-01-01

    Three aspects of work on aqueous phase transport by diffusion through porous granites are considered (1) The formation factor and long range connectivity of pore structure. (2) The effect of degraded fissure surfaces on diffusion into the main pore structure. (3) Effect of overburden pressures at depth on diffusion rates. Experiments were conducted on Cornish carnmenellis granite. (U.K.)

  11. Shear-Induced Phase Separation in Aqueous Polymer Solutions: Temperature-Sensitive Microgels and Linear Polymer Chains

    NARCIS (Netherlands)

    Stieger, M.A.; Richtering, W.

    2003-01-01

    The influence of shear flow on the phase separation of aqueous poly(N-isopropylacrylamide) (PNiPAM) microgel suspensions was investigated by means of rheo-turbidity and rheo-small angle neutron scattering (rheo-SANS) and compared to the behavior of linear PNiPAM macromolecules. The rheological

  12. Study of complex formation of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel

    International Nuclear Information System (INIS)

    Ismailova, M.M.; Egorova, L.A.; Khamidov, B.O.

    1993-01-01

    Present article is devoted to study of complex formation of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel. The condition of cobalt in various rate of oxidation in acrylamide aqueous solutions was studied. The concentration conditions of stability of system Co(II)-Co(III) were defined. The composition of coordination compounds of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel was determined.

  13. Containment and recovery of a light non-aqueous phase liquid plume at a woodtreating facility

    International Nuclear Information System (INIS)

    Crouse, D.; Powell, G.; Hawthorn, S.; Weinstock, S.

    1997-01-01

    A woodtreating site in Montana used a formulation (product) of 5 percent pentachlorophenol and 95 percent diesel fuel as a carrier liquid to pressure treat lumber. Through years of operations approximately 378,500 liters of this light non-aqueous phase liquid (LNAPL) product spilled onto the ground and soaked into the groundwater. A plume of this LNAPL product flowed in a northerly direction toward a stream located approximately 410 meters from the pressure treatment building. A 271-meter long high density polyethylene (HDPE) containment cutoff barrier wall was installed 15 meters from the stream to capture, contain, and prevent the product from migrating off site. This barrier was extended to a depth of 3.7 meters below ground surface and allowed the groundwater to flow beneath it. Ten product recovery wells, each with a dual-phase pumping system, were installed within the plume, and a groundwater model was completed to indicate how the plume would be contained by generating a cone of influence at each recovery well. The model indicated that the recovery wells and cutoff barrier wall would contain the plume and prevent further migration. To date, nearly 3 1/2 year's later, approximately 106,000 liters of product have been recovered

  14. WxC-β-SiC Nanocomposite Catalysts Used in Aqueous Phase Hydrogenation of Furfural

    Directory of Open Access Journals (Sweden)

    Jacek Rogowski

    2017-11-01

    Full Text Available This study investigates the effects of the addition of tungsten on the structure, phase composition, textural properties and activities of β-SiC-based catalysts in the aqueous phase hydrogenation of furfural. Carbothermal reduction of SiO2 in the presence of WO3 at 1550 °C in argon resulted in the formation of WxC-β-SiC nanocomposite powders with significant variations in particle morphology and content of WxC-tipped β-SiC nano-whiskers, as revealed by TEM and SEM-EDS. The specific surface area (SSA of the nanocomposite strongly depended on the amount of tungsten and had a notable impact on its catalytic properties for the production of furfuryl alcohol (FA and tetrahydrofurfuryl alcohol (THFA. Nanocomposite WxC-β-SiC catalysts with 10 wt % W in the starting mixture had the highest SSA and the smallest WxC crystallites. Some 10 wt % W nanocomposite catalysts demonstrated up to 90% yield of THFA, in particular in the reduction of furfural derived from biomass, although the reproducible performance of such catalysts has yet to be achieved.

  15. Formation of U(IV) Nanoparticles and Their Growth Mechanism in Mildly Acidic Aqueous Phases

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Wan Sik; Kim, Sun Tae; Cho, Hye Ryun; Jung, Euo Chang [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Previous studies suggest that U(IV) nanoparticle (NP) formation is one of key steps in mineralization or immobilization of uranium which can be mediated either by microbes or by abiotic geochemical reactions. Colloidal NPs in a groundwater system are potential carrier phases influencing RN migration in subsurface environment. However, the mechanism of U(IV) NP formation and the potential reaction intermediates during this solid phase formation process have not been elucidated in detail so far. In this study we attempted to examine the U(IV) nanoparticle formation reactions preceded by the hydrolysis of U{sup 4+} at different pHs, concentrations and temperatures. The kinetics of U(IV) NP formation from dissolved U(IV) species was monitored under mildly acidic conditions (pH 2 ∼ 3) mainly by using UV-Vis absorption spectrophotometry. Dynamic light scattering (DLS) analysis, nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) were used to characterize the NPs produced during the reactions. The results demonstrate that the U(IV) NP formation process is very sensitive toward temperature variation. The main outcome of this study is the discovery of the autocatalytic nature of U(IV) NP formation from the supersaturated U(OH){sup 3+} solution in a mildly acidic aqueous solution. The structure of reaction intermediates is proposed to contain oxide linkage. In the presentation the proposed mechanism of the U(IV) NP formation reaction and the properties of primary NPs and their clusters will be discussed in detail.

  16. WxC-β-SiC Nanocomposite Catalysts Used in Aqueous Phase Hydrogenation of Furfural.

    Science.gov (United States)

    Rogowski, Jacek; Andrzejczuk, Mariusz; Berlowska, Joanna; Binczarski, Michal; Kregiel, Dorota; Kubiak, Andrzej; Modelska, Magdalena; Szubiakiewicz, Elzbieta; Stanishevsky, Andrei; Tomaszewska, Jolanta; Witonska, Izabela Alina

    2017-11-22

    This study investigates the effects of the addition of tungsten on the structure, phase composition, textural properties and activities of β-SiC-based catalysts in the aqueous phase hydrogenation of furfural. Carbothermal reduction of SiO₂ in the presence of WO₃ at 1550 °C in argon resulted in the formation of W x C-β-SiC nanocomposite powders with significant variations in particle morphology and content of W x C-tipped β-SiC nano-whiskers, as revealed by TEM and SEM-EDS. The specific surface area (SSA) of the nanocomposite strongly depended on the amount of tungsten and had a notable impact on its catalytic properties for the production of furfuryl alcohol (FA) and tetrahydrofurfuryl alcohol (THFA). Nanocomposite W x C-β-SiC catalysts with 10 wt % W in the starting mixture had the highest SSA and the smallest W x C crystallites. Some 10 wt % W nanocomposite catalysts demonstrated up to 90% yield of THFA, in particular in the reduction of furfural derived from biomass, although the reproducible performance of such catalysts has yet to be achieved.

  17. Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams

    International Nuclear Information System (INIS)

    Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N.; Das, Sadananda; Pandey, Ashok K.; Kumar, Sangita D.; Reddy, A.V.R.

    2012-01-01

    Highlights: ► Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. ► Membranes offered high capacity and selectivity for fluoride in aqueous media. ► Quantitative uptake (80 ± 5%) of fluoride. ► Fast sorption kinetics. ► Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic–organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for ≈76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg −1 ), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

  18. Comparison of colorimetric m ethods for the quantification of model proteins in aqueous two-phase systems

    OpenAIRE

    Glyk, Anna; Heinisch, Sandra L.; Scheper, Thomas; Beutel, Sascha

    2015-01-01

    In the current study, the quantification of different model proteins in the presence of typical aqueous two-phase system components was investigated by using the Bradford and bicinchoninic acid (BCA) assays. Each phase-forming component above 1 and 5 wt% had considerable effects on the protein quantification in both assays, respectively, resulting in diminished protein recoveries/absorption values by increasing poly(ethylene glycol) (PEG)/salt concentration and PEG molecular weight. Therefore...

  19. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata) Seeds and Recycling of Phase Components.

    Science.gov (United States)

    Amid, Mehrnoush; Manap, Mohd Yazid; Hussin, Muhaini; Mustafa, Shuhaimi

    2015-06-17

    Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w) Triton X-100 and 20% (w/w) xylitol, at 56.2% of tie line length (TLL), (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases) and a crude load of 25% (w/w) at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase.

  20. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata Seeds and Recycling of Phase Components

    Directory of Open Access Journals (Sweden)

    Mehrnoush Amid

    2015-06-01

    Full Text Available Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w Triton X-100 and 20% (w/w xylitol, at 56.2% of tie line length (TLL, (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases and a crude load of 25% (w/w at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase.

  1. Experimental study and modelling of competitive adsorption equilibria of aromatics in liquid phase on X and Y faujasites; Etude experimentale et modelisation des equilibres d'adsorption competitive d'aromatiques en phase liquide sur des faujasites X et Y

    Energy Technology Data Exchange (ETDEWEB)

    Tournier, H.

    2000-10-13

    The separation of p-xylene from C{sub 8} aromatics is performed industrially by selective adsorption on zeolitic molecular sieves. The aim of this work is to study and model adsorption equilibria of C{sub 8} and C{sub 10} aromatics on X and Y zeolites. The experimental data are obtained by an entirely automated equipment allowing to work in a large range of temperature (50 deg. C - 250 deg. C). With this equipment, we can follow the evolution of the composition of the liquid phase and determine the composition of the adsorbed phase at equilibrium by a mass balance calculation and with an inert component. Two analytical techniques are used to determine the composition of the liquid phase: (1) a classical method using a gas chromatograph (GC) allowed to measure selectivities in the concentration range (3%-97%) in a component; (2) an original method based on the use and on the measure of {sup 13}C labelled xylenes was developed to investigate the ranges of strongly contrasting concentrations [0-3%] and [97%-100%] in a component, which are representative of high purity domains. Lastly, three thermodynamic models are used to describe the adsorption equilibria: the Langmuir-Freundlich model, the quasi-chemical model and the statistical model. The last model is the more interesting, because it is based on physical considerations. A new statistical model has been developed with taking into account some observations coming from adsorption phenomenon in zeolites. (author)

  2. Theoretical Investigation of the Structural Stabilities of Ceria Surfaces and Supported Metal Nanocluster in Vapor and Aqueous Phases

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhibo [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Liu, Ning [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Chen, Biaohua [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Li, Jianwei [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Mei, Donghai [Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States

    2018-01-25

    Understanding the structural stability and dynamics at the interface between the solid metal oxide and aqueous phase is significant in a variety of industrial applications including heterogeneous catalysis and environmental remediation. In the present work, the stabilities of three low-index ceria (CeO2) surfaces, i.e., (111), (110) and (100) in vapor and aqueous phases were studied using ab initio molecular dynamics simulations and density functional theory (DFT) calculations. Gibbs surface free energies as a function of temperature, water partial pressure, and water coverages were calculated using DFT based atomistic thermodynamic approach. On the basis of surface free energies, the morphology and exposed surface structures of the CeO2 nanoparticle were predicted using Wulff construction principle. It is found that the partially hydroxylated (111) and (100) are two major surface structures of CeO2 nanoparticles in vapor phase at ambient temperature (300 K). As the temperature increases, the fully dehydrated (111) surface gradually becomes the most dominant surface structure. While in aqueous phase, the exposed surface of the CeO2 nanoparticle is dominated by the hydroxylated (110) structure at 393 K. Finally, the morphology and stability of a cuboctahedron Pt13 nanocluster supported on CeO2 surfaces in both gas and aqueous phases were investigated. In gas phase, the supported Pt13 nanocluster has the tendency to wetting the CeO2 surface due to the strong metal-support interaction. The calculated interaction energies suggest the CeO2(110) surface provides the best stability for the Pt13 nanocluster. The CeO2 supported Pt13 nanoclusters are oxidized. Compared to the gas phase, the morphology of the CeO2 supported Pt13 nanocluster is less distorted due to the solvation effect provided by surrounding water molecules in aqueous phase. More electrons are transferred from the Pt13 nanocluster to the CeO2 support, implying the supported Pt13 nanocluster is further

  3. Affinity partitioning of human antibodies in aqueous two-phase systems.

    Science.gov (United States)

    Rosa, P A J; Azevedo, A M; Ferreira, I F; de Vries, J; Korporaal, R; Verhoef, H J; Visser, T J; Aires-Barros, M R

    2007-08-24

    The partitioning of human immunoglobulin (IgG) in a polymer-polymer and polymer-salt aqueous two-phase system (ATPS) in the presence of several functionalised polyethylene glycols (PEGs) was studied. As a first approach, the partition studies were performed with pure IgG using systems in which the target protein remained in the bottom phase when the non-functionalised systems were tested. The effect of increasing functionalised PEG concentration and the type of ligand were studied. Afterwards, selectivity studies were performed with the most successful ligands first by using systems containing pure proteins and an artificial mixture of proteins and, subsequently, with systems containing a Chinese hamster ovary (CHO) cells supernatant. The PEG/phosphate ATPS was not suitable for the affinity partitioning of IgG. In the PEG/dextran ATPS, the diglutaric acid functionalised PEGs (PEG-COOH) displayed great affinity to IgG, and all IgG could be recovered in the top phase when 20% (w/w) of PEG 150-COOH and 40% (w/w) PEG 3350-COOH were used. The selectivity of these functionalised PEGs was evaluated using an artificial mixture of proteins, and PEG 3350-COOH did not show affinity to IgG in the presence of typical serum proteins such as human serum albumin and myoglobin, while in systems with PEG 150-COOH, IgG could be recovered with a yield of 91%. The best purification of IgG from the CHO cells supernatant was then achieved in a PEG/dextran ATPS in the presence of PEG 150-COOH with a recovery yield of 93%, a purification factor of 1.9 and a selectivity to IgG of 11. When this functionalised PEG was added to the ATPS, a 60-fold increase in selectivity was observed when compared to the non-functionalised systems.

  4. Cryptographically Blinded Games: Leveraging Players' Limitations for Equilibria and Profit

    DEFF Research Database (Denmark)

    Hubacek, Pavel; Park, Sunoo

    2014-01-01

    In this work we apply methods from cryptography to enable mutually distrusting players to implement broad classes of mediated equilibria of strategic games without trusted mediation. Our implementation uses a pre-play 'cheap talk' phase, consisting of non- binding communication between players...

  5. Hydrostatic Equilibria of Rotating Stars with Realistic Equation of State

    Science.gov (United States)

    Yasutake, Nobutoshi; Fujisawa, Kotaro; Okawa, Hirotada; Yamada, Shoichi

    Stars rotate generally, but it is a non-trivial issue to obtain hydrostatic equilibria for rapidly rotating stars theoretically, especially for baroclinic cases, in which the pressure depends not only on the density, but also on the temperature and compositions. It is clear that the stellar structures with realistic equation of state are the baroclinic cases, but there are not so many studies for such equilibria. In this study, we propose two methods to obtain hydrostatic equilibria considering rotation and baroclinicity, namely the weak-solution method and the strong-solution method. The former method is based on the variational principle, which is also applied to the calculation of the inhomogeneous phases, known as the pasta structures, in crust of neutron stars. We found this method might break the balance equation locally, then introduce the strong-solution method. Note that our method is formulated in the mass coordinate, and it is hence appropriated for the stellar evolution calculations.

  6. Analysis of Solid and Aqueous Phase Products from Hydrothermal Carbonization of Whole and Lipid-Extracted Algae

    Directory of Open Access Journals (Sweden)

    Amber Broch

    2013-12-01

    Full Text Available Microalgae have tremendous potential as a feedstock for production of liquid biofuels, particularly biodiesel fuel via transesterification of algal lipids. However, biodiesel production results in significant amounts of algal residues, or “lipid extracted algae” (LEA. Suitable utilization of the LEA residue will improve the economics of algal biodiesel. In the present study, we evaluate the hydrothermal carbonization (HTC of whole and lipid extracted algal (Spirulina maxima feedstocks in order to produce a solid biofuel (hydrochar and value-added co-products in the aqueous phase. HTC experiments were performed using a 2-L Parr reactor (batch type at 175–215 °C with a 30-min holding time. Solid, aqueous and gaseous products were analyzed using various laboratory methods to evaluate the mass and carbon balances, and investigate the existence of high value chemicals in the aqueous phase. The HTC method is effective in creating an energy dense, solid hydrochar from both whole algae and LEA at lower temperatures as compared to lignocellulosic feedstocks, and is effective at reducing the ash content in the resulting hydrochar. However, under the treatment temperatures investigated, less than 1% of the starting dry algae mass was recovered as an identified high-value chemical in the aqueous phase.

  7. Phase diagrams of high-order critical phenomene and high-temperature equilibria in the H2O-HgI2-PbI2 system

    International Nuclear Information System (INIS)

    Valyashko, V.M.; Urusova, M.A.

    1996-01-01

    The paper studies the principal schemes of complete state diagram of volatile component-two non-volatile components three-component system with tricritical point and sequence of phase transformations at variation of temperature, pressure and composition of mixture. H 2 O-HgI 2 -PbI 2 system, solid phase dissolving process, stratification of solutions and critical phenomena under 200-400 deg C are studied experimentally. General nature of the system phase diagram and parameters of three-phase equilibrium critical point (tricritical point), that is, gas-liquid 1 -liquid 2 are determined. 17 refs., 8 figs., 3 tabs

  8. Learning to Play Efficient Coarse Correlated Equilibria

    KAUST Repository

    Borowski, Holly P.; Marden, Jason R.; Shamma, Jeff S.

    2018-01-01

    The majority of the distributed learning literature focuses on convergence to Nash equilibria. Coarse correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However

  9. Partial Cooperative Equilibria: Existence and Characterization

    Directory of Open Access Journals (Sweden)

    Amandine Ghintran

    2010-09-01

    Full Text Available We study the solution concepts of partial cooperative Cournot-Nash equilibria and partial cooperative Stackelberg equilibria. The partial cooperative Cournot-Nash equilibrium is axiomatically characterized by using notions of rationality, consistency and converse consistency with regard to reduced games. We also establish sufficient conditions for which partial cooperative Cournot-Nash equilibria and partial cooperative Stackelberg equilibria exist in supermodular games. Finally, we provide an application to strategic network formation where such solution concepts may be useful.

  10. Basalt Reactivity Variability with Reservoir Depth in Supercritical CO2 and Aqueous Phases

    Energy Technology Data Exchange (ETDEWEB)

    Schaef, Herbert T.; McGrail, B. Peter; Owen, Antionette T.

    2011-04-01

    Long term storage of CO{sub 2} in geologic formations is currently considered the most attractive option to reduce greenhouse gas emissions while continuing to utilize fossil fuels for energy production. Injected CO{sub 2} is expected to reside as a buoyant water-saturated supercritical fluid in contact with reservoir rock, the caprock system, and related formation waters. As was reported for the first time at the GHGT-9 conference, experiments with basalts demonstrated surprisingly rapid carbonate mineral formation occurring with samples suspended in the scCO{sub 2} phase. Those experiments were limited to a few temperatures and CO{sub 2} pressures representing relatively shallow (1 km) reservoir depths. Because continental flood basalts can extend to depths of 5 km or more, in this paper we extend the earlier results across a pressure-temperature range representative of these greater depths. Different basalt samples, including well cuttings from the borehole used in a pilot-scale basalt sequestration project (Eastern Washington, U.S.) and core samples from the Central Atlantic Magmatic Province (CAMP), were exposed to aqueous solutions in equilibrium with scCO{sub 2} and water-rich scCO{sub 2} at six different pressures and temperatures for select periods of time (30 to 180 days). Conditions corresponding to a shallow injection of CO{sub 2} (7.4 MPa, 34 C) indicate limited reactivity with basalt; surface carbonate precipitates were not easily identified on post-reacted basalt grains. Basalts exposed under identical times appeared increasingly more reacted with simulated depths. Tests, conducted at higher pressures (12.0 MPa) and temperatures (55 C), reveal a wide variety of surface precipitates forming in both fluid phases. Under shallow conditions tiny clusters of aragonite needles began forming in the wet scCO{sub 2} fluid, whereas in the CO{sub 2} saturated water, cation substituted calcite developed thin radiating coatings. Although these types of coatings

  11. Infiltration characteristics of non-aqueous phase liquids in undisturbed loessal soil cores

    Institute of Scientific and Technical Information of China (English)

    WANG Yunqiang; SHAO Ming'an

    2009-01-01

    The widespread contamination of soils and aquifers by non-aqueous phase liquids (NAPL), such as crude oil, poses serious environmental and health hazards globally. Understanding the infiltration characteristics of NAPL in soil is crucial in mitigating or remediating soil contamination. The infiltration characteristics of crude and diesel oils into undisturbed loessal soil cores, collected in polymethyl methacrylate cylindrical columns, were investigated under a constant fluid head (3 cm) of either crude oil or diesel oil. The infiltration rate of both crude and diesel oils decreased exponentially as wetting depth increased with time. Soil core size and bulk density both had a significant effect on NAPL infiltration through the undisturbed soil cores; a smaller core size or a greater bulk density both reduced oil penetration to depth. Compacting soil in areas susceptible to oil spills may be an effective way to reduce contamination. The infiltration of NAPL into soil cores was spatially anisotropic and heterogeneous, thus recording the data at four points on the soil core is a good way to improve the accuracy of experimental results. Our results provided information about crude and diesel oils, rather than their components, and may have practical value for remediation of contaminated loessal soils.

  12. Molecular dynamics simulation of cyclodextrin aggregation and extraction of Anthracene from non-aqueous liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xinzhe [Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); School of Environment, Tsinghua University, Beijing 100084 (China); Wu, Guozhong [Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Chen, Daoyi, E-mail: chen.daoyi@sz.tsinghua.edu.cn [Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2016-12-15

    Cyclodextrin (CD) extraction is widely used for the remediation of polycyclic aromatic hydrocarbons (PAH) pollution, but it remains unclear about the influence of CD aggregation on the PAH transport from non-aqueous liquid phase to water. The atomistic adsorption and complexation of PAHs (32 anthracenes) by CD aggregates (48 β-cyclodextrins) were studied by molecular dynamics simulations at hundreds of nanoseconds time scale. Results indicated that high temperature promoted the βCD aggregation in bulk oil, which was not found in bulk water. Nevertheless, the fractions of anthracenes entrapped inside the βCDs cavity in both scenarios were significantly increased when temperature increased from 298 to 328 K. Free energy calculation for the sub-steps of CD extraction demonstrated that the anthracenes could be extracted when the βCDs arrived at the water-oil interface or after the βCDs entered the bulk oil. The former was kinetic-controlled while the latter was thermodynamic-limited process. Results also highlighted the formation of porous structures by CD aggregates in water, which was able to sequestrate PAH clusters with the size obviously larger than the cavity diameter of individual CD. This provided an opportunity for the extraction of recalcitrant PAHs with molecular size larger than anthracenes by cyclodextrins.

  13. Liquid Phase Micro-Extraction of Linear Alkylbenzene Sulfonate Anionic Surfactants in Aqueous Samples

    Directory of Open Access Journals (Sweden)

    Jan Åke Jönsson

    2011-10-01

    Full Text Available Hollow fiber liquid phase micro-extraction (LPME of linear alkylbenzene sulfonates (LAS from aqueous samples was studied. Ion pair extraction of C10, C11, C12 and C13 homologues was facilitated with trihexylamine as ion-pairing agent, using di-n-hexylether as solvent for the supported liquid membrane (SLM. Effects of extraction time, acceptor buffer concentration, stirring speed, sample volume, NaCl and humic acids were studied. At 10–50 µg L−1 linear R2-coefficients were 0.99 for C10 and C11 and 0.96 for C12. RSD was typically ~15%. Three observations were especially made. Firstly, LPME for these analytes was unusually slow with maximum enrichment observed after 15–24 h (depending on sample volume. Secondly, the enrichment depended on LAS sample concentration with 35–150 times enrichment below ~150 µg L−1 and 1850–4400 times enrichment at 1 mg L−1. Thirdly, lower homologues were enriched more than higher homologues at low sample concentrations, with reversed conditions at higher concentrations. These observations may be due to the fact that LAS and the amine counter ion themselves influence the mass transfer at the water-SLM interface. The observations on LPME of LAS may aid in LPME application to other compounds with surfactant properties or in surfactant enhanced membrane extraction of other compounds.

  14. Infiltration characteristics of non-aqueous phase liquids in undisturbed loessal soil cores.

    Science.gov (United States)

    Wang, Yunqiang; Shao, Ming'an

    2009-01-01

    The widespread contamination of soils and aquifers by non-aqueous phase liquids (NAPL), such as crude oil, poses serious environmental and health hazards globally. Understanding the infiltration characteristics of NAPL in soil is crucial in mitigating or remediating soil contamination. The infiltration characteristics of crude and diesel oils into undisturbed loessal soil cores, collected in polymethyl methacrylate cylindrical columns, were investigated under a constant fluid head (3 cm) of either crude oil or diesel oil. The infiltration rate of both crude and diesel oils decreased exponentially as wetting depth increased with time. Soil core size and bulk density both had significant effects on NAPL infiltration through the undisturbed soil cores; a smaller core size or a greater bulk density could reduce oil penetration to depth. Compacting soil in areas susceptible to oil spills may be an effective stratage to reduce contamination. The infiltration of NAPL into soil cores was spatially anisotropic and heterogeneous, thus recording the data at four points on the soil core is a good stratage to improve the accuracy of experimental results. Our results revealed that crude and diesel oils, rather than their components, have a practical value for remediation of contaminated loessal soils.

  15. Expanded separation technique for chlorophyll metabolites in Oriental tobacco leaf using non aqueous reversed phase chromatography.

    Science.gov (United States)

    Ishida, Naoyuki

    2011-08-26

    An improved separation method for chlorophyll metabolites in Oriental tobacco leaf was developed. While Oriental leaf still gives the green color even after the curing process, little attention has been paid to the detailed composition of the remaining green pigments. This study aimed to identify the green pigments using non aqueous reversed phase chromatography (NARPC). To this end, liquid chromatograph (LC) equipped with a photo diode array detector (DAD) and an atmospheric pressure chemical ionization/mass spectrometer (APCI/MSD) was selected, because it is useful for detecting low polar non-volatile compounds giving green color such as pheophytin a. Identification was based on the wavelength spectrum, mass spectrum and retention time, comparing the analytes in Oriental leaf with the commercially available and synthesized components. Consequently, several chlorophyll metabolites such as hydroxypheophytin a, solanesyl pheophorbide a and solanesyl hydroxypheophorbide a were newly identified, in addition to typical green pigments such as chlorophyll a and pheophytin a. Chlorophyll metabolites bound to solanesol were considered the tobacco specific components. NARPC expanded the number of detectable low polar chlorophyll metabolites in Oriental tobacco leaf. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Precious Metals Supported on Alumina and Their Application for Catalytic Aqueous Phase Reforming of Glycerol

    Directory of Open Access Journals (Sweden)

    Kiky Corneliasari Sembiring

    2015-11-01

    Full Text Available The high cost of Pt based catalyst for aqueous phase reforming (APR reaction makes it advantageous to develop less cost of other metals for the same reaction. APR is hydrogen production process from biomass-derived source at mild condition near 500 K and firstly reported by Dumesic and co-worker. The use of hydrogen as environmentally friendly energy carrier has been massively encouraged over the last year. When hydrogen is used in fuel cell for power generation, it produces a little or no pollutants. The aim of this study is to study the effect of some precious metal catalysts for APR process. Due to investigation of metal catalysts for APR process, four precious metals (Cu, Co, Zn, Ni supported on γ-Al2O3 with 20% feeding amount have been successfully prepared by impregnation method. Those precious metals were identified as promising catalysts for APR. The catalysts were characterized by N2 physisorption at 77 K, X-Ray Diffraction (XRD and Fourier Transform-Infra Red (FT-IR. The catalytic performance was investigated at 523 K and autogenous pressure in a batch reactor with glycerol concentration of 10%. The gaseous hydrogen product was observed over the prepared catalysts by GC. It was found that performance of catalysts to yield the hydrogen product was summarized as follow Cu/γ-Al2O3 > Co/γ-Al2O3 > Zn/γ-Al2O3 > Ni/γ-Al2O3.

  17. submitter Aqueous phase oxidation of sulphur dioxide by ozone in cloud droplets

    CERN Document Server

    Hoyle, C R; Järvinen, E; Saathoff, H; Dias, A; El Haddad, I; Gysel, M; Coburn, S C; Tröstl, J; Bernhammer, A -K; Bianchi, F; Breitenlechner, M; Corbin, J C; Craven, J; Donahue, N M; Duplissy, J; Ehrhart, S; Frege, C; Gordon, H; Höppel, N; Heinritzi, M; Kristensen, T B; Molteni, U; Nichman, L; Pinterich, T; Prévôt, A S H; Simon, M; Slowik, J G; Steiner, G; Tomé, A; Vogel, A L; Volkamer, R; Wagner, A C; Wagner, R; Wexler, A S; Williamson, C; Winkler, P M; Yan, C; Amorim, A; Dommen, J; Curtius, J; Gallagher, M W; Flagan, R C; Hansel, A; Kirkby, J; Kulmala, M; Möhler, O; Stratmann, F; Worsnop, D R; Baltensperger, U

    2016-01-01

    The growth of aerosol due to the aqueous phase oxidation of sulfur dioxide by ozone was measured in laboratory-generated clouds created in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN). Experiments were performed at 10 and −10 °C, on acidic (sulfuric acid) and on partially to fully neutralised (ammonium sulfate) seed aerosol. Clouds were generated by performing an adiabatic expansion – pressurising the chamber to 220 hPa above atmospheric pressure, and then rapidly releasing the excess pressure, resulting in a cooling, condensation of water on the aerosol and a cloud lifetime of approximately 6 min. A model was developed to compare the observed aerosol growth with that predicted using oxidation rate constants previously measured in bulk solutions. The model captured the measured aerosol growth very well for experiments performed at 10 and −10 °C, indicating that, in contrast to some previous studies, the oxidation rates of SO2 in ...

  18. Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats.

    Science.gov (United States)

    Soares, Ruben R G; Azevedo, Ana M; Van Alstine, James M; Aires-Barros, M Raquel

    2015-08-01

    For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Extraction and recovery of 2-butoxyethanol from aqueous phases containing high saline concentration

    Directory of Open Access Journals (Sweden)

    Katherine E. Manz

    2016-09-01

    Full Text Available Ethylene glycol monobutyl ether (EGBE, also known as 2-butoxyethanol (2-BE, has been identified as a contaminant in hydraulic fracturing fluids. In order to determine the presence of 2-BE in hydraulic fracturing chemical additives, a reliable method for recovering 2-BE from aqueous phases by liquid-liquid extraction combined with gas chromatography/mass spectrometry (GC/MS was established. The liquid-liquid extraction method was applied to samples matrices containing various amounts of salt. Using methylene chloride for liquid-liquid extraction in a sample to solvent ratio of 1:3, ≥99% 2-BE recovery may be achieved with less than 5% standard error. The limit of detection was determined to be 0.957 mg L−1 2-BE. Accuracy was determined to be 2.58% and precision was determined using the coefficient of variation, which was 3.5%. The method was used to recover 2-BE in a hydraulic fracturing chemical additive called Revert Flow and to quantify the weight percent of 2-BE in the chemical additive. Weight percent of two additional components of Revert Flow, D-limonene and 1-butoxy-2-propanol, were also determined. We also used the method to determine the abiotic of 2-BE in water, which was 5.55 days. The persistence of 2-BE in hydraulic fracturing fluid was also investigated and determined that 2-BE is more persistent in this environment.

  20. A green deep eutectic solvent-based aqueous two-phase system for protein extracting.

    Science.gov (United States)

    Xu, Kaijia; Wang, Yuzhi; Huang, Yanhua; Li, Na; Wen, Qian

    2015-03-15

    As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n=3), 1.6057% (n=3) and 1.6132% (n=3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV-vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES-protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. One-pot aqueous phase catalytic conversion of sorbitol to gasoline over nickel catalyst

    International Nuclear Information System (INIS)

    Weng, Yujing; Qiu, Songbai; Xu, Ying; Ding, Mingyue; Chen, Lungang; Zhang, Qi; Ma, Longlong; Wang, Tiejun

    2015-01-01

    Highlights: • Directly production gasoline (C5–C12 alkanes) from biomass-derived sugar alcohol sorbitol. • Temperature of STG (553–593 K) was lower than that of traditional methanol to gasoline (MTG) (623–773 K). • Gasoline yield of 46.9% and C7–C12 hydrocarbons reached up to 45.5% in the gasoline products. - Abstract: The carbon chain extension and hydrodeoxygenation steps play critical roles in the high-energy-density hydrocarbons production. In this paper, a systematic study had been carried out to investigate one-pot aqueous phase catalytic conversion of sorbitol to gasoline (STG) over bifunctional Ni-based catalysts. Characterization technologies of N 2 physisorption, X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and NH 3 temperature-programmed desorption (NH 3 -TPD) were used to study the textural properties, phase compositions, acid behavior and morphologies of the catalysts. The catalytic performances were tested in a fixed bed reactor. It was found that the physically mixed Ni/HZSM-5 and Ni/silica-gel (mesoporous SG) catalyst realized the carbon chain extension and exhibited excellent performances on hydrodeoxygenation (HDO) reaction (46.9% of gasoline (C5–C12) yield and 45.5% of C7–C12 hydrocarbons in the gasoline products). Especially, the temperature of STG (553–593 K) was lower obviously than that of the traditional methanol to gasoline (MTG) process (623–773 K). It provided a novel transformation of sorbitol to long-chain alkanes by one-pot process over the bifunctional catalyst (Ni@HZSM-5/SG), wherein hydrodeoxygenation, ketonization and aldol condensation steps were integrated

  2. Characterization of bovine serum albumin partitioning behaviors in polymer-salt aqueous two-phase systems.

    Science.gov (United States)

    Chow, Yin Hui; Yap, Yee Jiun; Tan, Chin Ping; Anuar, Mohd Shamsul; Tejo, Bimo Ario; Show, Pau Loke; Ariff, Arbakariya Bin; Ng, Eng-Poh; Ling, Tau Chuan

    2015-07-01

    In this paper, a linear relationship is proposed relating the natural logarithm of partition coefficient, ln K for protein partitioning in poly (ethylene glycol) (PEG)-phosphate aqueous two-phase system (ATPS) to the square of tie-line length (TLL(2)). This relationship provides good fits (r(2) > 0.98) to the partition of bovine serum albumin (BSA) in PEG (1450 g/mol, 2000 g/mol, 3350 g/mol, and 4000 g/mol)-phosphate ATPS with TLL of 25.0-50.0% (w/w) at pH 7.0. Results also showed that the plot of ln K against pH for BSA partitioning in the ATPS containing 33.0% (w/w) PEG1450 and 8.0% (w/w) phosphate with varied working pH between 6.0 and 9.0 exhibited a linear relationship which is in good agreement (r(2) = 0.94) with the proposed relationship, ln K = α' pH + β'. These results suggested that both the relationships proposed could be applied to correlate and elucidate the partition behavior of biomolecules in the polymer-salt ATPS. The influence of other system parameters on the partition behavior of BSA was also investigated. An optimum BSA yield of 90.80% in the top phase and K of 2.40 was achieved in an ATPS constituted with 33.0% (w/w) PEG 1450 and 8.0% (w/w) phosphate in the presence of 8.5% (w/w) sodium chloride (NaCl) at pH 9.0 for 0.3% (w/w) BSA load. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  3. In-cloud multiphase behaviour of acetone in the troposphere: gas uptake, Henry's law equilibrium and aqueous phase photooxidation.

    Science.gov (United States)

    Poulain, Laurent; Katrib, Yasmine; Isikli, Estelle; Liu, Yao; Wortham, Henri; Mirabel, Philippe; Le Calvé, Stéphane; Monod, Anne

    2010-09-01

    Acetone is ubiquitous in the troposphere. Several papers have focused in the past on its gas phase reactivity and its impact on tropospheric chemistry. However, acetone is also present in atmospheric water droplets where its behaviour is still relatively unknown. In this work, we present its gas/aqueous phase transfer and its aqueous phase photooxidation. The uptake coefficient of acetone on water droplets was measured between 268 and 281K (γ=0.7 x 10(-2)-1.4 x 10(-2)), using the droplet train technique coupled to a mass spectrometer. The mass accommodation coefficient α (derived from γ) was found in the range (1.0-3.0±0.25) x 10(-2). Henry's law constant of acetone was directly measured between 283 and 298K using a dynamic equilibrium system (H((298K))=(29±5)Matm(-1)), with the Van't Hoff expression lnH(T)=(5100±1100)/T-(13.4±3.9). A recommended value of H was suggested according to comparison with literature. The OH-oxidation of acetone in the aqueous phase was carried out at 298K, under two different pH conditions: at pH=2, and under unbuffered conditions. In both cases, the formation of methylglyoxal, formaldehyde, hydroxyacetone, acetic acid/acetate and formic acid/formate was observed. The formation of small amounts of four hydroperoxides was also detected, and one of them was identified as peroxyacetic acid. A drastic effect of pH was observed on the yields of formaldehyde, one hydroperoxide, and, (to a lesser extent) acetic acid/acetate. Based on the experimental observations, a chemical mechanism of OH-oxidation of acetone in the aqueous phase was proposed and discussed. Atmospheric implications of these findings were finally discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Experimental Investigation and Thermodynamic Assessment of Phase Equilibria in the PLLA/Dioxane/Water Ternary System for Applications in the Biomedical Field.

    Science.gov (United States)

    Ruggiero, Flavia; Netti, Paolo Antonio; Torino, Enza

    2015-12-01

    Fundamental understanding of thermodynamic of phase separation plays a key role in tuning the desired features of biomedical devices. In particular, phase separation of ternary solution is of remarkable interest in processes to obtain biodegradable and biocompatible architectures applied as artificial devices to repair, replace, or support damaged tissues or organs. In these perspectives, thermally induced phase separation (TIPS) is the most widely used technique to obtained porous morphologies and, in addition, among different ternary systems, polylactic acid (PLLA)/dioxane/water has given promising results and has been largely studied. However, to increase the control of TIPS-based processes and architectures, an investigation of the basic energetic phenomena occurring during phase separation is still required. Here we propose an experimental investigation of the selected ternary system by using isothermal titration calorimetric approach at different solvent/antisolvent ratio and a thermodynamic explanation related to the polymer-solvents interactions in terms of energetic contribution to the phase separation process. Furthermore, relevant information about the phase diagrams and interaction parameters of the studied systems are furnished in terms of liquid-liquid miscibility gap. Indeed, polymer-solvents interactions are responsible for the mechanism of the phase separation process and, therefore, of the final features of the morphologies; the knowledge of such data is fundamental to control processes for the production of membranes, scaffolds and several nanostructures. The behavior of the polymer at different solvent/nonsolvent ratios is discussed in terms of solvation mechanism and a preliminary contribution to the understanding of the role of the hydrogen bonding in the interface phenomena is also reported. It is the first time that thermodynamic data of a ternary system are collected by mean of nano-isothermal titration calorimetry (nano-ITC). Supporting

  5. Oxidation of magnetite in aerated aqueous media

    International Nuclear Information System (INIS)

    Taylor, P.; Owen, D.G.

    1993-04-01

    Metastable equilibria involving phases less stable than hematite can be significantly more oxidizing than the calculated equilibrium between well-crystallized hematite and magnetite. In this report, generalized solubility and stability relationships between magnetite and Fe 2 O 3 .xH 2 O phases are derived to describe the metastable equilibria. Experiments with synthetic magnetite powders in aerated aqueous solutions show that crystalline hematite is formed within days at temperatures above 100 C in pure water or solutions containing anions (e.g., Cl - , SO 4 2 - , HCO 3 - ) that do not form very strong surface complexes with iron oxides. In the presence of dissolved phosphate or silica, however, the dissolution-precipitation route to hematite is strongly inhibited, and maghemite is a persistent metastable product. Thus, phosphate or silica are expected to delay the approach to magnetite-hematite equilibrium in aerated groundwaters conditioned by magnetite. These findings are presented in the context of nuclear fuel waste disposal. (author). 63 refs., 1 tab., 11 figs

  6. Aqueous two-phase (polyethylene glycol + sodium sulfate) system for caffeine extraction: Equilibrium diagrams and partitioning study

    International Nuclear Information System (INIS)

    Araujo Sampaio, Daniela de; Mafra, Luciana Igarashi; Yamamoto, Carlos Itsuo; Forville de Andrade, Eriel; Oberson de Souza, Michèle; Mafra, Marcos Rogério; Castilhos, Fernanda de

    2016-01-01

    Highlights: • Binodal curves of PEG (400, 4000 and 6000) + Na_2SO_4 ATPS were determined. • Tie-lines were experimentally determined for aqueous (PEG 400 + Na_2SO_4) system. • Influence of caffeine on LLE of aqueous (PEG 400 + Na_2SO_4) system was investigated. • Partitioning of caffeine in aqueous (PEG 400 + Na_2SO_4) system was investigated. • Caffeine partition showed to be dependent on temperature and TLL. - Abstract: Environmental friendly methods for liquid–liquid extraction have been taken into account due to critical conditions and ecotoxicological effects potentially produced by organic solvents applied in traditional methods. Liquid–liquid extraction using aqueous two phase systems (ATPSs) presents advantages when compared to traditional liquid–liquid extraction. (Polyethylene glycol (PEG) + sodium sulfate + water) ATPS was applied to study partition of caffeine. Binodal curves for ATPSs composed of PEG of different molecular weights (400 g · mol"−"1, 4000 g · mol"−"1 and 6000 g · mol"−"1) sodium sulfate + water were determined by cloud point method at three different temperatures (293.15, 313.15 and 333.15) K. Liquid–liquid equilibrium (LLE) data (tie-lines, slope of the tie-line and tie-lines length) were obtained applying a gravimetric method proposed by Merchuck and co-workers at the same temperatures for aqueous (PEG 400 + sodium sulfate) and aqueous (PEG 400 + sodium sulfate + caffeine) systems. Reliability of the experimental tie-line (TL) data was evaluated using the equations reported by Othmer–Tobias and satisfactory linearity was obtained. Concerning to aqueous (PEG + sodium sulfate) system, the results pointed out that the higher PEG molecular weight the largest is the heterogeneous region. Moreover, temperature showed not to be relevant on binodal curves behavior, but it influenced on tie-line slopes. Partitioning of caffeine in aqueous (PEG 400 + sodium sulfate) system was investigated at different temperatures

  7. The impact of uni-univalent electrolytes on (water + acetic acid + toluene) equilibria: Representation with electrolyte-NRTL model

    International Nuclear Information System (INIS)

    Saien, Javad; Fattahi, Mahdi; Mozafarvandi, Maryam

    2014-01-01

    Highlights: • Experimental LLE data for water + acetic acid + toluene + NaCl or KCl were reported. • The salting-out effect was detected; indicating the stronger effect of NaCl. • The electrolyte-NRTL model was adequately used to correlate the phase equilibria. • A good agreement was observed between calculated and experimental tie-lines. - Abstract: The presence of salts can significantly alter the (liquid + liquid) equilibrium and extraction process. In this work, a study was conducted on the (liquid + liquid) equilibria of (water + acetic acid + toluene + sodium chloride or potassium chloride) at temperatures (288.2, 298.2 and 313.2) K. This chemical system, irrespective of salt, is frequently used in (liquid + liquid) extraction investigations. The selected salt concentrations in initial aqueous solutions were (0.9 and 1.7) mol · L −1 . The results show that salting-out effect of the salts was significant, so that an enhancement in the acetic acid distribution coefficient was achieved within (15.6 to 66.8)% with NaCl and within (2.5 to 37.6)% with KCl. Meantime, high separation factors were found at low temperatures and low solute concentrations. The electrolyte-NRTL model was satisfactorily used to correlate the phase equilibria. In this regard for each salt, the temperature dependent binary interaction parameters between components were calculated. The predicted tie-line mole fractions give root-mean square deviation (RMSD) values of only 0.0038 and 0.0045 for the systems containing NaCl and KCl, respectively

  8. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part IV. Applications to mixtures of CO2 with alkanes

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Ali, Shahid; Kontogeorgis, Georgios

    2015-01-01

    The thermodynamic properties of pure gaseous, liquid or supercritical CO2 and CO2 mixtures with hydrocarbons and other compounds such as water, alcohols, and glycols are very important in many processes in the oil and gas industry. Design of such processes requires use of accurate thermodynamic...... models, capable of predicting the complex phase behavior of multicomponent mixtures as well as their volumetric properties. In this direction, over the last several years, the cubic-plus-association (CPA) thermodynamic model has been successfully used for describing volumetric properties and phase...

  9. Correlation and Prediction of Phase Equilibria and Volumetric Behaviour of Hyperbaric Binary Fluids Corrélation et prédiction des équilibres de phases et du comportement volumétrique de fluides hyperbares binaires

    Directory of Open Access Journals (Sweden)

    Stamataki S. K.

    2006-11-01

    Full Text Available The capabilities of cubic Equations of State (EoS in the correlation and the prediction of phase equilibria at hyperbaric conditions is examined. PVT data of pure compounds as well as VLE and volumetric data of binary mixtures up to 2000 bar are used. Correlation and prediction results are presented with the translated and modified Peng-Robinson (t - mPR EoS and EoS/GE models. The performance of cubic EoS with a single interaction parameter (kij in describing VLE is remarkable considering the level of pressures involved. The same is valid for the PVT results including the relative liquid volumes of the C1/nC24 system. With typical errors of about 10% deviations in pressure of 100 - 200 bar are, of course, encountered which can be eliminated by the use of second interaction coefficient in the covolume combining rule. Predicted kij values obtained from generalized correlations developed from low pressure VLE data provide reasonable results for systems with hydrocarbons up to nC16 even at high pressures, but fail for higher asymmetric ones. Volume translation is essential for PVT predictions. The temperature independent translation of t - mPR and that of Jhaveri and Yougren give very satisfactory results. LCVM provides the best results of the EoS/GE models studied and gives very good predictions for rather symmetric systems which become poorer with asymmetric ones at very high pressures. La capacité des équations d'état (EoS cubiques pour corréler et prédire les équilibres de phases en conditions hyperbares est analysée. Les données PVT de corps purs ainsi que les données d'équilibres liquide-vapeur (VLE et volumétriques pour des mélanges binaires, jusqu'à 2000 bar sont utilisées. Les résultats des corrélations et des prédictions sont présentés pour l'équation de Peng-Robinson translatée et modifiée (t - mPR, ainsi que pour les modèles EoS/GE. Les performances des EoS cubiques avec un paramètre d'interaction unique (kij pour

  10. Stackelberg equilibria and horizontal differentiation

    OpenAIRE

    Lambertini, Luca

    1993-01-01

    This paper proposes a taxonomy of the Stackelberg equilibria emerging from a standard game of horizontal differentiation à la Hotelling in which the strategy set of the sellers in the location stage is the real axis. Repeated leadership appears the most advantageous position. Furthermore, this endogenously yields vertical differentiation between products at equilibrium.

  11. Multiple equilibria of divertor plasmas

    International Nuclear Information System (INIS)

    Vu, H.X.; Prinja, A.K.

    1993-01-01

    A one-dimensional, two-fluid transport model with a temperature-dependent neutral recycling coefficient is shown to give rise to multiple equilibria of divertor plasmas (bifurcation). Numerical techniques for obtaining these multiple equilibria and for examining their stability are presented. Although these numerical techniques have been well known to the scientific community, this is the first time they have been applied to divertor plasma modeling to show the existence of multiple equilibria as well as the stability of these solutions. Numerical and approximate analytical solutions of the present one-dimensional transport model both indicate that there exists three steady-state solutions corresponding to (1) a high-temperature, low-density equilibrium, (2) a low-temperature, high-density equilibrium, and (3) an intermediate-temperature equilibrium. While both the low-temperature and the high-temperature equilibria are stable, with respect to small perturbations in the plasma conditions, the intermediate-temperature equilibrium is physically unstable, i.e., any small perturbation about this equilibrium will cause a transition toward either the high-temperature or low-temperature equilibrium

  12. Integration of carboxyl modified magnetic particles and aqueous two-phase extraction for selective separation of proteins.

    Science.gov (United States)

    Gai, Qingqing; Qu, Feng; Zhang, Tao; Zhang, Yukui

    2011-07-15

    Both of the magnetic particle adsorption and aqueous two-phase extraction (ATPE) were simple, fast and low-cost method for protein separation. Selective proteins adsorption by carboxyl modified magnetic particles was investigated according to protein isoelectric point, solution pH and ionic strength. Aqueous two-phase system of PEG/sulphate exhibited selective separation and extraction for proteins before and after magnetic adsorption. The two combination ways, magnetic adsorption followed by ATPE and ATPE followed by magnetic adsorption, for the separation of proteins mixture of lysozyme, bovine serum albumin, trypsin, cytochrome C and myloglobin were discussed and compared. The way of magnetic adsorption followed by ATPE was also applied to human serum separation. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Different Diversity and Distribution of Archaeal Community in the Aqueous and Oil Phases of Production Fluid From High-Temperature Petroleum Reservoirs

    Directory of Open Access Journals (Sweden)

    Bo Liang

    2018-04-01

    Full Text Available To get a better knowledge on how archaeal communities differ between the oil and aqueous phases and whether environmental factors promote substantial differences on microbial distributions among production wells, we analyzed archaeal communities in oil and aqueous phases from four high-temperature petroleum reservoirs (55–65°C by using 16S rRNA gene based 454 pyrosequencing. Obvious dissimilarity of the archaeal composition between aqueous and oil phases in each independent production wells was observed, especially in production wells with higher water cut, and diversity in the oil phase was much higher than that in the corresponding aqueous phase. Statistical analysis further showed that archaeal communities in oil phases from different petroleum reservoirs tended to be more similar, but those in aqueous phases were the opposite. In the high-temperature ecosystems, temperature as an environmental factor could have significantly affected archaeal distribution, and archaeal diversity raised with the increase of temperature (p < 0.05. Our results suggest that to get a comprehensive understanding of petroleum reservoirs microbial information both in aqueous and oil phases should be taken into consideration. The microscopic habitats of oil phase, technically the dispersed minuscule water droplets in the oil could be a better habitat that containing the indigenous microorganisms.

  14. Phase equilibria in the Zr-Si-B ternary system (Zr-Si-ZrB{sub 2} region) at 1 173 K

    Energy Technology Data Exchange (ETDEWEB)

    Han, Feng; Luo, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Lab. of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Lab. of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

    2017-10-15

    The isothermal section of the Zr-Si-B ternary system (Zr-Si-ZrB{sub 2} region) at 1 173 K has been experimentally determined. All equilibrated alloys were characterized via X-ray powder diffraction and scanning electron microscopy equipped with energy-dispersive X-ray analysis. A ternary phase Zr{sub 5}(Si{sub 0.86}B{sub 0.14}){sub 3} was found at 1 173 K. The experimental results show that the isothermal section consists of 11 single-phase regions, 26 two-phase regions and 13 three-phase regions. The existence of eight compounds, i.e. ZrSi{sub 2}, ZrSi, Zr{sub 5}Si{sub 4}, Zr{sub 3}Si{sub 2}, Zr{sub 2}Si, ZrB, ZrB{sub 2} and Zr{sub 5}(Si{sub 0.86}B{sub 0.14}){sub 3} in this system has been confirmed in the Zr-Si-ZrB{sub 2} region at 1 173 K.

  15. Towards CO2 sequestration and applications of CO2 hydrates: the effects of tetrahydrofuran on the phase equilibria of CO2 hydrates

    International Nuclear Information System (INIS)

    Khalik, M.S.; Peters, C.J.

    2006-01-01

    The increasing quantity of carbon dioxide (CO 2 ) in the atmosphere has caused widespread global concerns. Capturing CO 2 from its sources and stored it in the form of gas hydrates and application of CO 2 hydrates are among the proposed methods to overcome this problem. In order to make hydrate-based process more attractive, the use of cyclic ethers as promoters is suggested to reduce the required hydrate formation pressure and enhancing the corresponding kinetic rate. In the present work, tetrahydrofuran (THF) is chosen as a hydrate promoter, participating in forming hydrates and produces mixed hydrate together with CO 2 . The pressure and temperature ranges of hydrate stability region are carefully determined through phase equilibrium measurement of the ternary CO 2 , tetrahydrofuran (THF) and water systems. From the experimental results, it is confirmed that the presence of THF in CO 2 + water systems will extend the hydrate formation region to higher temperature at a constant pressure. The extension of the hydrate stability region is depended on the overall concentration of the ternary system. Moreover, four-phase equilibrium of H-Lw-Lv-V is observed in the system, which may be due to a liquid phase split. In the region where the four-phase equilibrium exists, the ternary system loses its concentration dependency of the hydrate equilibrium conditions. (Author)

  16. A Designer Fluid for Aluminum Phase Change Devices, Vol. 1 of 3: General Inorganic Aqueous Solution (IAS) Chemistry

    Science.gov (United States)

    2016-11-17

    out in wicked phase change heat transfer devices. Wen [18] used nanoparticle suspensions to successfully increase the boiling heat transfer...Aqueous Solution of an Anionic Surfactant,” Journal of Heat Transfer 122, No. 4: 708. [18] Wen , D. and Ding, Y., 2005, “Experimental Investigation...Li, Y., 1974, “Diffusion of Ions in Sea Water and in Deep -Sea Sediments,” Geochimica et Cosmochimica Acta, Vol. 88, pp. 703-714. [36] Negishi, K

  17. Thermal analysis and prediction of phase equilibria in the TiO{sub 2}-Bi{sub 2}O{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Martinez, Jaqueline, E-mail: jacky-411@hotmail.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico D.F (Mexico); Romero-Serrano, Antonio, E-mail: romeroipn@hotmail.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico D.F (Mexico); Hernandez-Ramirez, Aurelio, E-mail: aurelioh@hotmail.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico D.F (Mexico); Zeifert, Beatriz, E-mail: bzeifert@yahoo.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico D.F (Mexico); Gomez-Yanez, Carlos, E-mail: cgomezy@ipn.mx [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico D.F (Mexico); Martinez-Sanchez, Roberto, E-mail: roberto.martinez@cimav.edu.mx [CIMAV, Av. Miguel de Cervantes 120, Chihuahua C.P.31109 (Mexico)

    2011-03-20

    A thermodynamic study on the TiO{sub 2}-Bi{sub 2}O{sub 3} system was carried out using differential thermal analysis (DTA) and X-Ray diffraction (XRD) techniques covering the composition range from 65 to 90 mol% Bi{sub 2}O{sub 3}. From the XRD results the only two intermediate compounds in the Bi{sub 2}O{sub 3} rich region were Bi{sub 4}Ti{sub 3}O{sub 12} and Bi{sub 12}TiO{sub 20}. The Bi{sub 4}Ti{sub 3}O{sub 12} phase presents the well known plate-like morphology. The experimentally determined phase transition temperatures with DTA technique were compared with thermodynamic calculated results and good agreement was obtained. The DTA results also showed that the limit of the peritectic reaction between liquid and Bi{sub 4}Ti{sub 3}O{sub 12} occurs approximately at 90 mol% Bi{sub 2}O{sub 3}. The phase diagram of the TiO{sub 2}-Bi{sub 2}O{sub 3} system was calculated using a quasichemical model for the liquid phase. The thermodynamic properties of the intermediate compounds were estimated from the data of TiO{sub 2} and Bi{sub 2}O{sub 3} pure solids. In this manner, data for this binary system have been analysed and represented with a small adjustable parameter for the liquid phase.

  18. Molar mass fractionation in aqueous two-phase polymer solutions of dextran and poly(ethylene glycol).

    Science.gov (United States)

    Zhao, Ziliang; Li, Qi; Ji, Xiangling; Dimova, Rumiana; Lipowsky, Reinhard; Liu, Yonggang

    2016-06-24

    Dextran and poly(ethylene glycol) (PEG) in phase separated aqueous two-phase systems (ATPSs) of these two polymers, with a broad molar mass distribution for dextran and a narrow molar mass distribution for PEG, were separated and quantified by gel permeation chromatography (GPC). Tie lines constructed by GPC method are in excellent agreement with those established by the previously reported approach based on density measurements of the phases. The fractionation of dextran during phase separation of ATPS leads to the redistribution of dextran of different chain lengths between the two phases. The degree of fractionation for dextran decays exponentially as a function of chain length. The average separation parameters, for both dextran and PEG, show a crossover from mean field behavior to Ising model behavior, as the critical point is approached. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. On-the-Fly Kinetic Monte Carlo Simulation of Aqueous Phase Advanced Oxidation Processes.

    Science.gov (United States)

    Guo, Xin; Minakata, Daisuke; Crittenden, John

    2015-08-04

    We have developed an on-the-fly kinetic Monte Carlo (KMC) model to predict the degradation mechanisms and fates of intermediates and byproducts that are produced during aqueous-phase advanced oxidation processes (AOPs). The on-the-fly KMC model is composed of a reaction pathway generator, a reaction rate constant estimator, a mechanistic reduction module, and a KMC solver. The novelty of this work is that we develop the pathway as we march forward in time rather than developing the pathway before we use the KMC method to solve the equations. As a result, we have fewer reactions to consider, and we have greater computational efficiency. We have verified this on-the-fly KMC model for the degradation of polyacrylamide (PAM) using UV light and titanium dioxide (i.e., UV/TiO2). Using the on-the-fly KMC model, we were able to predict the time-dependent profiles of the average molecular weight for PAM. The model provided detailed and quantitative insights into the time evolution of the molecular weight distribution and reaction mechanism. We also verified our on-the-fly KMC model for the destruction of (1) acetone, (2) trichloroethylene (TCE), and (3) polyethylene glycol (PEG) for the ultraviolet light and hydrogen peroxide AOP. We demonstrated that the on-the-fly KMC model can achieve the same accuracy as the computer-based first-principles KMC (CF-KMC) model, which has already been validated in our earlier work. The on-the-fly KMC is particularly suitable for molecules with large molecular weights (e.g., polymers) because the degradation mechanisms for large molecules can result in hundreds of thousands to even millions of reactions. The ordinary differential equations (ODEs) that describe the degradation pathways cannot be solved using traditional numerical methods, but the KMC can solve these equations.

  20. Enhanced mobility of non aqueous phase liquid (NAPL) during drying of wet sand

    Science.gov (United States)

    Govindarajan, Dhivakar; Deshpande, Abhijit P.; Raghunathan, Ravikrishna

    2018-02-01

    Enhanced upward mobility of a non aqueous phase liquid (NAPL) present in wet sand during natural drying, and in the absence of any external pressure gradients, is reported for the first time. This mobility was significantly higher than that expected from capillary rise. Experiments were performed in a glass column with a small layer of NAPL-saturated sand trapped between two layers of water-saturated sand. Drying of the wet sand was induced by flow of air across the top surface of the wet sand. The upward movement of the NAPL, in the direction of water transport, commenced when the drying effect reached the location of the NAPL and continued as long as there was significant water evaporation in the vicinity of NAPL, indicating a clear correlation between the NAPL rise and water evaporation. The magnitude and the rate of NAPL rise was measured at different water evaporation rates, different initial locations of the NAPL, different grain size of the sand and the type of NAPL (on the basis of different NAPL-glass contact angle, viscosity and density). A positive correlation was observed between average rate of NAPL rise and the water evaporation while a negative correlation was obtained between the average NAPL rise rate and the NAPL properties of contact angle, viscosity and density. There was no significant correlation of average NAPL rise rate with variation of sand grain size between 0.1 to 0.5 mm. Based on these observations and on previous studies reported in the literature, two possible mechanisms are hypothesized -a) the effect of the spreading coefficient resulting in the wetting of NAPL on the water films created and b) a moving water film due to evaporation that "drags" the NAPL upwards. The NAPL rise reported in this paper has implications in fate and transport of chemicals in NAPL contaminated porous media such as soils and exposed dredged sediment material, which are subjected to varying water saturation levels due to drying and rewetting.

  1. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the southeast United States and co-benefit of SO2 emission controls

    Science.gov (United States)

    Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for...

  2. EQUILGAS: Program to estimate temperatures and in situ two-phase conditions in geothermal reservoirs using three combined FT-HSH gas equilibria models

    Science.gov (United States)

    Barragán, Rosa María; Núñez, José; Arellano, Víctor Manuel; Nieva, David

    2016-03-01

    Exploration and exploitation of geothermal resources require the estimation of important physical characteristics of reservoirs including temperatures, pressures and in situ two-phase conditions, in order to evaluate possible uses and/or investigate changes due to exploitation. As at relatively high temperatures (>150 °C) reservoir fluids usually attain chemical equilibrium in contact with hot rocks, different models based on the chemistry of fluids have been developed that allow deep conditions to be estimated. Currently either in water-dominated or steam-dominated reservoirs the chemistry of steam has been useful for working out reservoir conditions. In this context, three methods based on the Fischer-Tropsch (FT) and combined H2S-H2 (HSH) mineral-gas reactions have been developed for estimating temperatures and the quality of the in situ two-phase mixture prevailing in the reservoir. For these methods the mineral buffers considered to be controlling H2S-H2 composition of fluids are as follows. The pyrite-magnetite buffer (FT-HSH1); the pyrite-hematite buffer (FT-HSH2) and the pyrite-pyrrhotite buffer (FT-HSH3). Currently from such models the estimations of both, temperature and steam fraction in the two-phase fluid are obtained graphically by using a blank diagram with a background theoretical solution as reference. Thus large errors are involved since the isotherms are highly nonlinear functions while reservoir steam fractions are taken from a logarithmic scale. In order to facilitate the use of the three FT-HSH methods and minimize visual interpolation errors, the EQUILGAS program that numerically solves the equations of the FT-HSH methods was developed. In this work the FT-HSH methods and the EQUILGAS program are described. Illustrative examples for Mexican fields are also given in order to help the users in deciding which method could be more suitable for every specific data set.

  3. Effects of aggregation on the excitation dynamics of LH2 from Thermochromatium tepidum in aqueous phase and in chromatophores.

    Science.gov (United States)

    Yang, Fan; Yu, Long-Jiang; Wang, Peng; Ai, Xi-Cheng; Wang, Zheng-Yu; Zhang, Jian-Ping

    2011-06-23

    We carried out femtosecond magic-angle and polarized pump-probe spectroscopies for the light-harvesting complex 2 (LH2) from Thermochromatium (Tch.) tepidum in aqueous phase and in chromatophores. To examine the effects of LH2 aggregation on the dynamics of excitation energy transfer, dominant monodispersed and aggregated LH2s were prepared by controlling the surfactant concentrations. The aqueous preparations solubilized with different concentrations of n-dodecyl-β-D-maltoside (DDM) show similar visible-to-near-infrared absorption spectra, but distinctively different aggregation states, as revealed by using dynamic light scattering. The B800 → B850 intra-LH2 energy transfer time was determined to be 1.3 ps for isolated LH2, which, upon aggregation in aqueous phase or clustering in chromatophores, shortened to 1.1 or 0.9 ps, respectively. The light-harvesting complex 1 (LH1) of this thermophilic purple sulfur bacterium contains bacteriochlorophyll a absorbing at 915 nm (B915), and the LH2(B850) → LH1(B915) intercomplex transfer time in chromatophores was found to be 6.6 ps. For chromatophores, a depolarization time of 21 ps was derived from the anisotropy kinetics of B850*, which is attributed to the migration of B850* excitation before being trapped by LH1. In addition, the B850* annihilation is accelerated upon LH2 aggregation in aqueous phase, but it is much less severe upon LH2 clustering in the intracytoplasmic membrane. These results are helpful in understanding the light-harvesting function of a bacterial photosynthetic membrane incorporating different types of antenna complexes.

  4. High-Pressure Phase Equilibria in Systems Containing CO2 and Ionic Liquid of the [Cnmim][Tf2N] Type

    OpenAIRE

    Sedláková, Z. (Zuzana); Wagner, Z. (Zdeněk)

    2012-01-01

    In this review, we present a comparison of the high-pressure phase behaviour of binary systems constituted of CO2 and ionic liquids of the [Cn(m)mim][Tf2N] type. The comparative study shows that the solubility of CO2 in ionic liquids of the [Cnmim][Tf2N] type generally increases with increasing pressure and decreasing temperature, but some peculiarities have been observed. The solubility of CO2 in ionic liquid solvents was correlated using the Soave–Redlich–Kwong equation of state. The result...

  5. Novel monoclinic zirconolite in Bi2O3–CuO–Ta2O5 ternary system: Phase equilibria, structural and electrical properties

    International Nuclear Information System (INIS)

    Tan, K.B.; Chon, M.P.; Khaw, C.C.; Zainal, Z.; Taufiq Yap, Y.H.; Tan, P.Y.

    2014-01-01

    Highlights: • Novel BCT monoclinic zirconolite phase was prepared through solid state reaction. • Comprehensive study of reaction mechanism was performed by careful firing control. • Qualitative structural and phase analyses were conducted. • Electrical response in broad range of temperature and frequency was investigated. - Abstract: Synthesis of novel monoclinic zirconolite, Bi 1.92 Cu 0.08 (Cu 0.3 Ta 0.7 ) 2 O 7.06 (β-BCT) using solid state reaction had been finalised at the firing temperature of 900 °C over 24 h. The X–ray diffraction pattern of β-BCT was fully indexed on a monoclinic symmetry, space group, C2/c with lattice constants, a = 13.1052 (8), b = 7.6749 (5), c = 12.162 (6), α = γ = 90° and β = 101.32° (1), respectively. The reaction mechanism study indicated phase formation was greatly influenced by the reaction between intermediate bismuth tantalate binary phases and CuO at elevated temperatures. β-BCT was thermally stable up to a temperature of 900 °C and contained spherulite grains with sizes ranging from 1 to 14 μm. Electrical properties of this material were characterised over a broad temperature range covering temperatures from 10 K to 874 K. At the temperature of 304 K, two semicircles were discernible in complex Cole–Cole plot showing an insulating grain boundary with C gb = 6.63 × 10 −9 F cm −1 and a bulk response capacitance, C b = 6.74 × 10 −12 F cm −1 . The Power law frequency-dependent ac conductivity of β-BCT was apparent in three frequency regimes; a low–frequency plateau regime, a high-frequency plateau regime and a dispersive regime taking place in the temperature range of 220–576 K. The frequency-dependent ac conductivity of β-BCT with increasing temperature was attributed to the thermal activated electrical conduction mechanism within the structure

  6. Study of phase equilibria in LiIn(MoO4)2 - MeIn(MoO4)2 (Me - K, Rb) systems

    International Nuclear Information System (INIS)

    Smirnyagina, N.N.; Kozhevnikova, N.M.; Alekseev, F.P.; Mokhosoev, M.V.

    1983-01-01

    To determine the possibilities of formation of ternary molybdates, containing two different alkali cations and a cation of trivalent element, the qUasibinary LiIn(MoO 4 ) 2 -MeIn(MoO 4 ) 2 cross-sections of quaternary Li 2 O-Me 2 O-In 2 O 3 -MoO 3 , (Me-K, Rb) systems have been studied. Methods of X-ray phase-, differential thermal- and crystal optical analyses were used. The studied systems are eutectics with segregation; ternary compounds are not formed in theM

  7. RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

    Directory of Open Access Journals (Sweden)

    G. Malmary

    2001-12-01

    Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

  8. Thermodynamic study of phase equilibria in petroleum separation plants; Estudo termodinamico do equilibrio de fases em plantas de separacao de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ciro Rodolfo Santos; Duarte, Lindemberg de Jesus Nogueira [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Santos, Luiz Carlos Lobato [Universidade Federal da Bahia (UFBA), BA (Brazil)

    2012-07-01

    Through a thermodynamic approach of liquid-vapor separation it is possible to provide for a given load, of known composition and given temperature and pressure conditions, which are the volumes and the compositions of liquid and vapor phases in equilibrium. In this sense, the aim of this work is to analyze the separation conditions of the fluids produced in the well 1-FMO-001-BA, belonging to the Field School Project (ANP / UFBA), through a thermodynamic approach of phase equilibrium. This Well is characterized by being in an advanced stage of exploration with low oil and high gas production. Initially, the overall composition of the gas produced from the 1-FMO-001-BA was quantified by gas chromatography and its composition was similar to a typical natural gas found in the Reconcavo's basin. Then, the equilibrium constants were determined by Wilson empirical correlation, which could enable the determination of the dead oil composition. This oil showed low concentration of light hydrocarbons (e.g., methane, etc.) and moderate concentrations of heavy components (e.g., C{sub 10} {sub +}). Moreover, the original composition of the fluid that reaches the separator vessel had a similar chemical composition to the outlet gaseous stream of the separator vessel, proving that the Fazenda Mamoeiro's reservoir is classified as a gas reservoir. Finally, it was determined the relative density of the gas ({gamma} g = 0.8264), the specific gravity of the dead oil ({gamma} {sub o} = 0.7542), the API gravity (56.13) and gas-oil ratio (GOR 950.98 m{sup 3}std / m{sup 3}std), which are consistent with the data provided by PETROBRAS. (author)

  9. Phase equilibria and crystal chemistry of the CaO-½Gd2O3-CoOz system at 885 °C in air

    Science.gov (United States)

    Wong-Ng, W.; Laws, W.; Lapidus, S. H.; Ribaud, L.; Kaduk, J. A.

    2017-10-01

    The CaO-½Gd2O3-CoOz system prepared at 885 °C in air consists of two thermoelectric calcium cobaltate compounds, namely, the 2D thermoelectric oxide solid solution, (Ca3-xGdx)Co4O9-z (0 ≤ x ≤ 0.42) which has a misfit layered structure, and the 1D Ca3Co2O6 compound which consists of chains of alternating CoO6 trigonal prisms and CoO6 octahedra. Ca3Co2O6 was found to be a point compound. In the peripheral binary systems, Gd was not present in the Ca site of CaO, while a small solid solution region was identified for (Gd1-xCax)O(3-z)/2 (0 ≤ x ≤ 0.075). A solid solution region of distorted perovskite, (Gd1-xCax)CoO3-z (0 ≤ x ≤ 0.24, space group Pnma) was established. The structure of a member of the solid solution, (Gd0.92Ca0.08)CoO3-z, was determined using high resolution synchrotron radiation. A ternary oxide compound CaGdCoO4-z which has an orthorhombic structure (Bmab) was found to be stable at this temperature. Five solid solution tie-line regions and six three-phase regions were determined in the CaO-½Gd2O3-CoOz system. A comparison of the phase diagrams of the CaO-½R2O3-CoOz (R = La, Sm and Gd) systems is provided.

  10. Fabrication of platinum nanoparticles in aqueous solution and solid phase using amphiphilic PB-b-PEO copolymer nanoreactors

    International Nuclear Information System (INIS)

    Hoda, Numan; Budama, Leyla; Çakır, Burçin Acar; Topel, Önder; Ozisik, Rahmi

    2013-01-01

    Graphical abstract: TEM image of Pt nanoparticles produced by reducing by NaBH 4 within PB-b-PEO micelles in aqueous media (scale bar 1 nm). - Highlights: • Pt nanoparticles were synthesized within amphiphilic diblock copolymer micelles. • The effects of reducing agents and precursor dose on Pt np size were investigated. • The effect on fabrication of Pt np by reducing in aqueous and solid phases was compared. • The size of nanoparticles was about 1.4 nm for all doses and reducing agents types. - Abstract: Fabrication of Pt nanoparticles using an amphiphilic copolymer template in aqueous solution was achieved via polybutadiene-block-polyethyleneoxide copolymer micelles, which acted as nanoreactors. In addition, Pt nanoparticles were synthesized using hydrogen gas as the reducing agent in solid state for the first time to compare against solution synthesis. The influences of loaded precursor salt amount to micelles and the type of reducing agent on the size of nanoparticles were investigated through transmission electron microscopy. It was found that increasing the ratio of precursor salt to copolymer and using different type of reducing agent, even in solid phase reduction, did not affect the nanoparticle size. The average size of Pt nanoparticles was estimated to be 1.4 ± 0.1 nm. The reason for getting same sized nanoparticles was discussed in the light of nucleation, growth process, stabilization and diffusion of nanoparticles within micelles

  11. Synthesis and characterization of conditioned carbon with iron nanoparticles for the arsenic removal in aqueous phase

    International Nuclear Information System (INIS)

    Flores C, D. O.

    2012-01-01

    Using pineapple husks conditioned with carboxymethylcellulose, hexamine and ferric nitrate, a carbonaceous material was obtained with nanoparticles of Fe (C Fe), which was characterized and tested for arsenic removal in the aqueous phase. The microscopic study showed spheres 4 microns and filaments 100 nm wide, so as iron particles whose diameter decreases to an average of 38.81 nm, when pyrolysis time was increased to 180 min. their distribution in the carbonaceous matrix is homogeneous. According to energy dispersive X-ray spectroscopy, C Fe contains C (82.29%), O (7.23%), K (0.68%), Ca (3.77%) and Fe (6.25%) and its diffraction pattern shows the characteristic peak of Fe (0), which is not observed in the coal without iron. By neutron activation analysis were quantified Al, Br, Ce, Co, Cr, Cs, Eu, Hf, K, Mg, Mn, Na, Rb, Sb, Sc and Zn, they can be involved in the process of sorption of As (v) forming surface active sites. For C Fe and C B characterized by Fourier transform infrared spectrometry, groups C-H, C=O, C=C, -Nh, NH 2 , isocyanate and isonitrile were found, the last two were formed by the present hexamine. X-ray photoelectron spectroscopy showed energy states of C 1 and O 1 in pineapple shell washed, shell conditioned with iron, C Fe at different times and the pyrolysis coal without iron (C B). The material C Fe 180 presented a specific area of 167 m 2 /g and 7.12 ± 1 sites/nm 2 isoelectric point while pH i = 11.1 C B is 98.80 m 2 /g specific area and 1.5 ± 1 sites/nm 2 and pH i = 10.6, being favorable to the sorption process. The highest removal of As(v) for both materials was at ph = 2, fitting the kinetic data to pseudo-second order model. The isotherms as a function of concentration were adjusted to Freundlich model indicating multilayer chemisorption at specific sites of a heterogeneous medium. Characterization by scanning electron microscopy after the sample sorption Fe nanoparticles remain in the carbonaceous matrix being not affected by the

  12. Electrical resistivity for detecting subsurface non-aqueous phase liquids: A progress report

    International Nuclear Information System (INIS)

    Lee, K.H.; Shan, C.; Javandel, I.

    1995-06-01

    Soils and groundwater have been contaminated by hazardous substances at many places in the United States and many other countries. The contaminants are commonly either petroleum products or industrial solvents with very low solubility in water. These contaminants are usually called non-aqueous phase liquids (NAPLs). The cost of cleaning up the affected sites in the United States is estimated to be of the order of 100 billion dollars. In spite of the expenditure of several billion dollars during the last 15 years, to date, very few, if any major contaminated site has been restored. The presence of NAPL pools in the subsurface is believed to be the main cause for the failure of previous cleanup activities. Due to their relatively low water solubility, and depending on their volume, it takes tens or even hundreds of years to deplete the NAPL sources if they are not removed from the subsurface. The intrinsic electrical resistivity of most NAPLs is typically in the range of 10 7 to 10 12 Ω-m, which is several orders of magnitude higher than that of groundwater containing dissolved solids (usually in the range of a few Ω-m to a few thousand Ω-m). Although a dry soil is very resistive, the electrical resistivity of a wet soil is on the order of 100 Ω-m and is dependent on the extent of water saturation. For a given soil, the electrical resistivity increases with decrease of water saturation. Therefore, if part of the pore water is replaced by a NAPL, the electrical resistivity will increase. At many NAPL sites, both the vadose and phreatic zones can be partially occupied by NAPL pools. It is the great contrast in electrical resistivity between the NAPLs and groundwater that may render the method to be effective in detecting subsurface NAPLs at contaminated sites. The following experiments were conducted to investigate the change of the electrical resistivity of porous media when diesel fuel (NAPL) replaces part of the water

  13. Electron attachment to DNA single strands: gas phase and aqueous solution.

    Science.gov (United States)

    Gu, Jiande; Xie, Yaoming; Schaefer, Henry F

    2007-01-01

    The 2'-deoxyguanosine-3',5'-diphosphate, 2'-deoxyadenosine-3',5'-diphosphate, 2'-deoxycytidine-3',5'-diphosphate and 2'-deoxythymidine-3',5'-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3',5'-dTDP (0.17 eV) and 3',5'-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3',5'-dTDP > 3',5'-dCDP > 3',5'-dGDP > 3',5'-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3'-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3'-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3',5'-dADP(-) (0.26 eV) and 3',5'-dGDP(-) (0.32 eV) indicate that electron detachment might compete with reactions having high activation barriers

  14. Aqueous-phase photochemical oxidation and direct photolysis of vanillin - a model compound of methoxy phenols from biomass burning

    Science.gov (United States)

    Li, Y. J.; Huang, D. D.; Cheung, H. Y.; Lee, A. K. Y.; Chan, C. K.

    2014-03-01

    We present here experimental results on aqueous-phase (A) photochemical oxidation (with UV and OH radicals generated from H2O2 photolysis) and (B) direct photolysis (with only UV irradiation) of a methoxy phenol, vanillin (VL), as a model compound from biomass burning. Both on-line aerosol mass spectrometric (AMS) characterization and off-line chemical analyses were performed. AMS analyses of dried atomized droplets of the bulk reacting mixtures showed that VL almost entirely evaporates during the drying process. Large amounts of organic mass remained in the particle phase after reactions under both conditions. Under condition (A), AMS measured organic mass first increased rapidly and then decreased, attributable to the formation of non-volatile products and subsequent formation of smaller and volatile products, respectively. The oxygen-to-carbon (O : C) ratio of the products reached 1.5 after about 80 min, but dropped substantially thereafter. In contrast, organic mass increased slowly under condition (B). The O : C ratio reached 1.0 after 180 min. In off-line analyses, small oxygenates were detected under condition (A), while hydroxylated products and dimers of VL were detected under condition (B). Particle hygroscopic growth factor (GF) and cloud condensation nuclei (CCN) activity of the reacting mixtures were found to depend on both organic volume fraction and the degree of oxygenation of organics. Results show that (1) aqueous-phase processes can lead to the retention of a large portion of the organic mass in the particle phase; (2) once retained, this portion of organic mass significantly changes the hygroscopicity and CCN activity of the aerosol particles; (3) intensive photochemical oxidation gave rise to an O : C ratio as high as 1.5 but the ratio decreased as further oxidation led to smaller and more volatile products; and (4) polymerization occurred with direct photolysis, resulting in high-molecular-weight products of a yellowish color. This study

  15. Aqueous-phase photochemical oxidation and direct photolysis of vanillin - a model compound of methoxy-phenols from biomass burning

    Science.gov (United States)

    Li, Y. J.; Huang, D. D.; Cheung, H. Y.; Lee, A. K. Y.; Chan, C. K.

    2013-10-01

    We present here experimental results on aqueous-phase (A) photochemical oxidation (with UV and OH radicals generated from H2O2 photolysis) and (B) direct photolysis (with only UV irradiation) of a methoxy-phenol, vanillin (VL), as a model compound from biomass burning. Both on-line aerosol mass spectrometric (AMS) characterization and off-line chemical analyses were performed. AMS analyses of dried atomized droplets of the bulk reacting mixtures showed that VL almost entirely evaporates during the drying process. Large amounts of organic mass remained in the particle phase after reactions under both conditions. Under condition (A), AMS measured organic mass first increased rapidly and then decreased, attributable to the formation of non-volatile products and subsequent formation of smaller and volatile products, respectively. The oxygen-to-carbon (O:C) ratio of the products reached 1.5 after about 80 min, but dropped substantially thereafter. In contrast, organic mass increased slowly under condition (B). The O:C ratio reached 1.0 after 180 min. In off-line analyses, small oxygenates were detected under condition (A), while hydroxylated products and dimers of VL were detected under condition (B). Particle hygroscopic growth factor (GF) and cloud condensation nuclei (CCN) activity of the reacting mixtures were found to be dependent on both organic volume fraction and the degree of oxygenation of organics. Results show that (1) aqueous-phase processes can lead to the retention of a large portion of the organic mass in the particle phase; (2) once retained, this portion of organic mass significantly changes the hygroscopicity and CCN activity of the aerosol particles; (3) intensive photochemical oxidation gave rise to an O:C ratio as high as 1.5 but the ratio decreased as further oxidation led to smaller and more volatile products; and (4) polymerization occurred with direct photolysis, resulting in high-molecular-weight products of a yellowish color. This study

  16. Small GSH-Capped CuInS2 Quantum Dots: MPA-Assisted Aqueous Phase Transfer and Bioimaging Applications.

    Science.gov (United States)

    Zhao, Chuanzhen; Bai, Zelong; Liu, Xiangyou; Zhang, Yijia; Zou, Bingsuo; Zhong, Haizheng

    2015-08-19

    An efficient ligand exchange strategy for aqueous phase transfer of hydrophobic CuInS2/ZnS quantum dots was developed by employing glutathione (GSH) and mercaptopropionic acid (MPA) as the ligands. The whole process takes less than 20 min and can be scaled up to gram amount. The material characterizations show that the final aqueous soluble samples are solely capped with GSH on the surface. Importantly, these GSH-capped CuInS2/ZnS quantum dots have small size (hydrodynamic diameter quantum dots, for instance, CuInSe2 and CdSe/ZnS quantum dots. We further demonstrated that GSH-capped quantum dots could be suitable fluorescence markers to penetrate cell membrane and image the cells. In addition, the GSH-capped CuInS2 quantum dots also have potential use in other fields such as photocatalysis and quantum dots sensitized solar cells.

  17. Effects of solid/liquid phase fractionation on pH and aqueous species molality in subduction zone fluids

    Science.gov (United States)

    Zhong, X.; Galvez, M. E.

    2017-12-01

    Metamorphic fluids are a crucial ingredient of geodynamic evolution, i.e. heat transfer, rock mechanics and metamorphic/metasomatic reactions. During crustal evolution at elevated P and T, rock forming components can be effectively fractionated from the reactive rock system by at least two processes: 1. extraction from porous rocks by liquid phases such as solute-bearing (e.g. Na+, Mg2+) aqueous fluids or partial melts. 2. isolation from effective bulk rock composition due to slow intragranular diffusion in high-P refractory phases such as garnet. The effect of phase fractionation (garnet, partial melt and aqueous species) on fluid - rock composition and properties remain unclear, mainly due to a high demand in quantitative computations of the thermodynamic interactions between rocks and fluids over a wide P-T range. To investigate this problem, we build our work on an approach initially introduced by Galvez et al., (2015) with new functionalities added in a MATLAB code (Rubisco). The fluxes of fractionated components in fluid, melt and garnet are monitored along a typical prograde P-T path for a model crustal pelite. Some preliminary results suggest a marginal effect of fractionated aqueous species on fluid and rock properties (e.g. pH, composition), but the corresponding fluxes are significant in the context of mantle wedge metasomatism. Our work provides insight into the role of high-P phase fractionation on mass redistribution between the surface and deep Earth in subduction zones. Existing limitations relevant to our liquid/mineral speciation/fractionation model will be discussed as well. ReferencesGalvez, M.E., Manning, C.E., Connolly, J.A.D., Rumble, D., 2015. The solubility of rocks in metamorphic fluids: A model for rock-dominated conditions to upper mantle pressure and temperature. Earth Planet. Sci. Lett. 430, 486-498.

  18. (Liquid + liquid) equilibria of four alcohol–water systems containing 1,8-cineole at T = 298.15 K

    International Nuclear Information System (INIS)

    Li, Hengde; Feng, Zhangni; Wan, Li; Huang, Cheng; Zhang, Tianfei; Fang, Yanxiong

    2016-01-01

    Graphical abstract: (Liquid + liquid) equilibria of C_1–C_4 alcohol–water systems containing 1,8-cineole are presented. Distribution ratios of alcohol in the mixtures are examined. The immiscible region of the LLE systems is evaluated and discussed. - Highlights: • Ternary (liquid + liquid) equilibria containing 1,8-cineole are presented. • Distribution ratios of C_1–C_4 alcohol in the mixtures are examined. • The LLE values were correlated using the NRTL and UNIQUAC models. - Abstract: As an eco-friendly compound from essential oils, 1,8-cineole (cineole, eucalyptol) has the potential to replace the ozone depleting industrial solvents. This paper presents experimental (liquid + liquid) equilibrium (LLE) data for four alcohol–water systems containing 1,8-cineole. To evaluate the phase equilibrium properties of 1,8-cineole in aqueous alcohol mixtures, LLE values for the ternary systems (water + methanol or ethanol or 1-propanol or 1-butanol + 1,8-cineole) were determined with a tie-line method at T = 298.15 K under atmospheric pressure. The well-known Hand, Bachman and Othmer–Tobias equations were used to test the reliability of the experimental results. The binodal curves and distribution ratios of alcohol in the mixtures are shown and discussed. The experimental LLE values were satisfactorily correlated by the NRTL and UNIQUAC models.

  19. Nash Equilibria in Fisher Market

    Science.gov (United States)

    Adsul, Bharat; Babu, Ch. Sobhan; Garg, Jugal; Mehta, Ruta; Sohoni, Milind

    Much work has been done on the computation of market equilibria. However due to strategic play by buyers, it is not clear whether these are actually observed in the market. Motivated by the observation that a buyer may derive a better payoff by feigning a different utility function and thereby manipulating the Fisher market equilibrium, we formulate the Fisher market game in which buyers strategize by posing different utility functions. We show that existence of a conflict-free allocation is a necessary condition for the Nash equilibria (NE) and also sufficient for the symmetric NE in this game. There are many NE with very different payoffs, and the Fisher equilibrium payoff is captured at a symmetric NE. We provide a complete polyhedral characterization of all the NE for the two-buyer market game. Surprisingly, all the NE of this game turn out to be symmetric and the corresponding payoffs constitute a piecewise linear concave curve. We also study the correlated equilibria of this game and show that third-party mediation does not help to achieve a better payoff than NE payoffs.

  20. Vapor-liquid equilibria for the acetone-ethanol-n-propanol-tert-butanol-water system

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, K.; Uchida, K.; Kojima, K.

    1981-12-01

    This study deals with the measurement of vapor-liquid equilibria for the five-component system acetone-ethanol-n-propanol-tert-butanol-water at 760 mmHg and prediction of vapor-liquid equilibria by the ASOG group contribution method. The five-component system in this work is composed of a part of the components obtained during ethanol production by vapor-phase hydration of ethylene. 6 refs.

  1. Calculation of Binary Adsorption Equilibria: Hydrocarbons and Carbon Dioxide on Activated Carbon

    DEFF Research Database (Denmark)

    Marcussen, Lis; Krøll, A.

    1999-01-01

    Binary adsorption equilibria are calculated by means of a mathematical model for multicomponent mixtures combined with the SPD (Spreading Pressure Dependent) model for calculation of activity coefficients in the adsorbed phase. The model has been applied successfully for the adsorption of binary ...... mixtures of hydrocarbons and carbon dioxide on activated carbons. The model parameters have been determined, and the model has proven to be suited for prediction of adsorption equilibria in the investigated systems....

  2. Slow growth of the Rayleigh-Plateau instability in aqueous two phase systems

    NARCIS (Netherlands)

    Geschiere, S.D.; Ziemecka, I.; Van Steijn, V.; Koper, G.J.M.; Van Esch, J.H.; Kreutzer, M.T.

    2012-01-01

    This paper studies the Rayleigh-Plateau instability for co-flowing immiscible aqueous polymer solutions in a microfluidic channel. Careful vibration-free experiments with controlled actuation of the flow allowed direct measurement of the growth rate of this instability. Experiments for the

  3. Aqueous phase reforming of ethylene glycol - Role of intermediates in catalyst performance

    NARCIS (Netherlands)

    de Vlieger, Dennis; Mojet, Barbara; Lefferts, Leonardus; Seshan, Kulathuiyer

    2012-01-01

    Liquid product formation during the aqueous catalytic reforming of ethylene glycol (EG) was studied up to 450 °C and 250 bar pressure. Methanol, ethanol, and acetic acid were the main liquid by-products during EG reforming in the presence of alumina-supported Pt and Pt–Ni catalysts. The effect of

  4. An experimental study of Fe-Ni exchange between sulfide melt and olivine at upper mantle conditions: implications for mantle sulfide compositions and phase equilibria

    Science.gov (United States)

    Zhang, Zhou; von der Handt, Anette; Hirschmann, Marc M.

    2018-03-01

    The behavior of nickel in the Earth's mantle is controlled by sulfide melt-olivine reaction. Prior to this study, experiments were carried out at low pressures with narrow range of Ni/Fe in sulfide melt. As the mantle becomes more reduced with depth, experiments at comparable conditions provide an assessment of the effect of pressure at low-oxygen fugacity conditions. In this study, we constrain the Fe-Ni composition of molten sulfide in the Earth's upper mantle via sulfide melt-olivine reaction experiments at 2 GPa, 1200 and 1400 °C, with sulfide melt X_{{{Ni}}}^{{{Sulfide}}}={{Ni}}/{{Ni+{Fe}}} (atomic ratio) ranging from 0 to 0.94. To verify the approach to equilibrium and to explore the effect of {f_{{{O}2}}} on Fe-Ni exchange between phases, four different suites of experiments were conducted, varying in their experimental geometry and initial composition. Effects of Ni secondary fluorescence on olivine analyses were corrected using the PENELOPE algorithm (Baró et al., Nucl Instrum Methods Phys Res B 100:31-46, 1995), "zero time" experiments, and measurements before and after dissolution of surrounding sulfides. Oxygen fugacities in the experiments, estimated from the measured O contents of sulfide melts and from the compositions of coexisting olivines, were 3.0 ± 1.0 log units more reduced than the fayalite-magnetite-quartz (FMQ) buffer (suite 1, 2 and 3), and FMQ - 1 or more oxidized (suite 4). For the reduced (suites 1-3) experiments, Fe-Ni distribution coefficients K_{{D}}{}={(X_{{{Ni}}}^{{{sulfide}}}/X_{{{Fe}}}^{{{sulfide}}})}/{(X_{{{Ni}}^{{{olivine}}}/X_{{{Fe}}}^{{{olivine}}})}} are small, averaging 10.0 ± 5.7, with little variation as a function of total Ni content. More oxidized experiments (suite 4) give larger values of K D (21.1-25.2). Compared to previous determinations at 100 kPa, values of K D from this study are chiefly lower, in large part owing to the more reduced conditions of the experiments. The observed difference does not seem

  5. Enhancing the lateral-flow immunoassay for detection of proteins using an aqueous two-phase micellar system.

    Science.gov (United States)

    Mashayekhi, Foad; Le, Alexander M; Nafisi, Parsa M; Wu, Benjamin M; Kamei, Daniel T

    2012-10-01

    The lateral-flow (immuno)assay (LFA) has been widely investigated for the detection of molecular, macromolecular, and particle targets at the point-of-need due to its ease of use, rapid processing, and minimal power and laboratory equipment requirements. However, for some analytes, such as certain proteins, the detection limit of LFA is inferior to lab-based assays, such as the enzyme-linked immunosorbent assay, and needs to be improved. One solution for improving the detection limit of LFA is to concentrate the target protein in a solution prior to the detection step. In this study, a novel approach was used in the context of an aqueous two-phase micellar system comprised of the nonionic surfactant Triton X-114 to concentrate a model protein, namely transferrin, prior to LFA. Proteins have been shown to partition, or distribute, fairly evenly between the two phases of an aqueous two-phase system, which in turn results in their limited concentration in one of the two phases. Therefore, larger colloidal gold particles decorated with antibodies for transferrin were used in the concentration step to bind to transferrin and aid its partitioning into the top, micelle-poor phase. By manipulating the volume ratio of the two coexisting micellar phases and combining the concentration step with LFA, the transferrin detection limit of LFA was improved by tenfold from 0.5 to 0.05 μg/mL in a predictive manner. In addition to enhancing the sensitivity of LFA, this universal concentration method could also be used to improve other detection assays.

  6. Cold-induced aqueous acetonitrile phase separation: A salt-free way to begin quick, easy, cheap, effective, rugged, safe.

    Science.gov (United States)

    Shao, Gang; Agar, Jeffrey; Giese, Roger W

    2017-07-14

    Cooling a 1:1 (v/v) solution of acetonitrile and water at -16° C is known to result in two clear phases. We will refer to this event as "cold-induced aqueous acetonitrile phase separation (CIPS)". On a molar basis, acetonitrile is 71.7% and 13.6% in the upper and lower phases, respectively, in our study. The phase separation proceeds as a descending cloud of microdroplets. At the convenient temperature (typical freezer) employed here the lower phase is rather resistant to solidification, although it emerges from the freezer as a solid if various insoluble matter is present at the outset. In a preliminary way, we replaced the initial (salting-out) step of a representative QuEChERS procedure with CIPS, applying this modified procedure ("CIPS-QuEChERS") to a homogenate of salmon (and partly to beef). Three phases resulted, where only the upper, acetonitrile-rich phase is a liquid (that is completely clear). The middle phase comprises ice and precipitated lipids, while the lower phase is the residual matrix of undissolved salmon or meat. Treating the upper phase from salmon, after isolation, with anhydrous MgSO 4 and C18-Si (typical QuEChERS dispersive solid phase extraction sorbents), and injecting into a GC-MS in a nontargeted mode, gives two-fold more preliminary hits for chemicals, and also number of spiked pesticides recovered, relative to that from a comparable QuEChERS method. In part, this is because of much higher background signals in the latter case. Further study of CIPS-QuEChERS is encouraged, including taking advantage of other QuERChERS conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Magnetoacoustic heating and FCT-equilibria in the belt pinch

    International Nuclear Information System (INIS)

    Erckmann, V.

    1983-02-01

    In the HECTOR belt pinch of high β plasma is produced by magnetic compression in a Tokamak geometry. After compresseion the initial β value can be varied between 0.2 and 0.8. During 5 μs the plasma is further heated by a fast magnetoacoustic wave with a frequency near the first harmonic of the ion cyclotronfrequency. For the first time the β-value of a pinch plasma could be increased further from 0.34 after compression to 0.46 at the end of the rf-heating cycle. By proper selection of the final β-value the region for resonance absorption of the heating wave can be shifted. Strong heating (200 MW) has been observed in the cases, where the resonance region has been located in the center of the plasma. In deuterium discharges an increase in ion temperature is observed during the heating process, whereas the electrons are energetically decoupled, showing no temperature increase. Strong plasma losses are found in the 200 MW range after the rf-heating process. The dominant mechanisms are charge exchange collisions with neutral gas atoms. During rf-heating and the subsequent cooling phase the magnetic flux is frozen due to the high conductivity of the plasma. The observed equilibria could be identified as flux conserving Tokamak (FCT) equilibria. Based on a two-dimensional code the time-evolution of the equilibria has been calculated. The q-profiles are time-independent, with increasing β the magnetic axis of the plasma is shifted towards the outer boundary of the torus, and finally the linear relation between β and βsub(pol), which is characteristic for low-β-equilibria, is no longer valid. Thus for the first time the existence of FCT-equilibria at high β has been demonstrated experimentally together with a qualitative agreement with FCT-theory. (orig./AH) [de

  8. Chelate-Modified Fenton Reaction for the Degradation of Trichloroethylene in Aqueous and Two-Phase Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Scott [Univ of KY, dept of chemical and materials engineering; lynch, Andrew [Univ of KY, dept of chemical and materials engineering; Bachas, Leonidas [Univ of KY, Dept of Chemistry; hampson, Steve [Univ of KY Center for Applied Energy Research - KY Research Consortium of Energy and Environment; Ormsbee, Lindelle [Univ of KY Center for Applied Energy Research - KY Research Consortium of Energy and Environment; Bhattacharyya, Dibakar [Univ of KY, dept of chemical and materials engineering

    2008-06-01

    The Standard Fenton reaction has been used for In-Situ Chemical Oxidation (ISCO) of toxic organics in groundwater. However, it requires low pH operating conditions, and thus has limitations for in situ applications. In addition, hydroxyl radicals are rapidly consumed by hydroxyl scavengers found in the subsurface. These problems are alleviated through the chelate-modified Fenton (hydroxyl radical) reaction, which includes the addition of nontoxic chelate (L) such as citrate or gluconic acid. This chelate allows the reaction to take place at bear neutral pH and control hydrogen peroxide consumption by binding to Fe(II), forming an FeL complex. The chelate also binds to Fe(III), preventing its precipitation as ferric hydroxide and thus prevents problems associated with injection well plugging. The rate of TCE dechlorination in chelate-modified Fenton systems is a function of pH, H2O2 concentration, and FE:L ratio. The primary objective of this research is to model and apply this process to the destruction of trichloroethylene (TCE) present in both the aqueous and organic (in the form of droplets) phases. Experimentation proved the chelate-modified Fenton reaction effectively dechlorinates TCE in both the aqueous and organic phases at near-neutral pH. Other focuses of this work include determining the effect of [L]:[Fe] ratios on H2O2 and TCE degradation as well as reusability of the FE citrate solution under repeated H2O2 injections. Generalized models were developed to predict the concentration of TCE in the aqueous phase and TCE droplet radius as a function of time using established hydroxyl radial kinetics and mass transfer relationships.

  9. Aqueous Two-Phase Systems: A New Approach for the Determination of Brilliant Blue FCF in Water and Food Samples

    Directory of Open Access Journals (Sweden)

    Sabah Shiri

    2013-01-01

    Full Text Available A novel, simple, and more sensitive spectrophotometric procedure has been developed for the determination of brilliant blue FCF in water and food samples by an aqueous two-phase system (ATPS. In this method, adequate amount of polyethylene glycol/ sodium carbonate (PEG-4000/Na2CO3 was added to aqueous solution for formation of a homogeneous solution. To the mixture solution, suitable amount of Na2CO3 was added, the mixture solution was shaken until the salt was dissolved, and then it was separated into two clear phases easily and rapidly. The target analyte in the water sample was extracted into the polyethylene glycol phase. After extraction, measuring the absorbance at 634 nm was done. The effects of different parameters such as polyethylene glycol (type and concentration, pH, salt (type and amount, centrifuge time, and temperature on the ATPS of dye was investigated and optimum conditions were established. Linear calibration curves were obtained in the range of 0.25–750 ng/mL for brilliant blue FCF under optimum conditions. Detection limit based on three times the standard deviation of the blank (3Sb was 0.12 ng/mL. The relative standard deviation (RSD for 400 ng/mL was 3.14%. The method was successfully applied to the determination of brilliant blue FCF in spiked samples with satisfactory results. The relative recovery was between 96.0 and 102.2%.

  10. Determination of heavy polycyclic aromatic hydrocarbons by non-aqueous reversed phase liquid chromatography: Application and limitation in refining streams.

    Science.gov (United States)

    Panda, Saroj K; Muller, Hendrik; Al-Qunaysi, Thunayyan A; Koseoglu, Omer R

    2018-01-19

    The heavy polycyclic aromatic hydrocarbons (HPAHs) cause detrimental effects to hydrocracker operations by deactivating the catalysts and depositing in the downstream of the reactor/ exchangers. Therefore, it is essential to continuously monitor the accumulation of HPAHs in a hydrocracker unit. To accurately measure the concentration of HPAHs, the development of a fast and reliable analytical method is inevitable. In this work, an analytical method based on non-aqueous reversed phase chromatography in combination with high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was developed. As a first step, five different types of stationary phases were evaluated for the separation of HPAHs in non-aqueous mode and the best suited phase was further used for the fractionation of HPAHs in a fractionator bottom sample obtained from a refinery hydrocracker unit. The eight major fractions or peaks obtained from the separation were further characterized by UV spectroscopy and FT-ICR MS and the compounds in the fractions were tentatively confirmed as benzoperylene, coronene, methylcoronene, naphthenocoronene, benzocoronene, dibenzoperylene, naphthocoronene and ovalene. The developed liquid chromatography method can be easily adapted in a refinery laboratory for the quantitation of HPAHs in hydrocracking products. The method was further tested to check the interference of sulfur aromatics and/or large alkylated aromatic hydrocarbons on the determination of HPAHs in hydrocracking products. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Linear free energy relationships between aqueous phase hydroxyl radical reaction rate constants and free energy of activation.

    Science.gov (United States)

    Minakata, Daisuke; Crittenden, John

    2011-04-15

    The hydroxyl radical (HO(•)) is a strong oxidant that reacts with electron-rich sites on organic compounds and initiates complex radical chain reactions in aqueous phase advanced oxidation processes (AOPs). Computer based kinetic modeling requires a reaction pathway generator and predictions of associated reaction rate constants. Previously, we reported a reaction pathway generator that can enumerate the most important elementary reactions for aliphatic compounds. For the reaction rate constant predictor, we develop linear free energy relationships (LFERs) between aqueous phase literature-reported HO(•) reaction rate constants and theoretically calculated free energies of activation for H-atom abstraction from a C-H bond and HO(•) addition to alkenes. The theoretical method uses ab initio quantum mechanical calculations, Gaussian 1-3, for gas phase reactions and a solvation method, COSMO-RS theory, to estimate the impact of water. Theoretically calculated free energies of activation are found to be within approximately ±3 kcal/mol of experimental values. Considering errors that arise from quantum mechanical calculations and experiments, this should be within the acceptable errors. The established LFERs are used to predict the HO(•) reaction rate constants within a factor of 5 from the experimental values. This approach may be applied to other reaction mechanisms to establish a library of rate constant predictions for kinetic modeling of AOPs.

  12. Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols

    Directory of Open Access Journals (Sweden)

    M. M. Chim

    2017-12-01

    Full Text Available Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C5H8O4 droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85 % through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C5 hydroxyl functionalization product (C5H8O5 and a C4 fragmentation product (C4H6O3. These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon–carbon bond scission of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model coupled with the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients (AIOMFAC model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from

  13. Partition Coefficients of Amino Acids, Peptides, and Enzymes in Dextran + Poly(Ethylene Glycol) + Water Aqueous Two-Phase Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kakisaka, Keijiro.; Shindo, Takashi.; Iwai, Yoshio.; Arai, Yasuhiko. [Kyushu University, Fukuoka (Japan). Department of Chemical Systems and Engineering

    1998-12-01

    Partition coefficients are measured for five amino acids(aspartic acid, asparagine, methionine, cysteine and histidine) and tow peptides(glycyl-glycine and hexa-glycine) in dextran + poly(ethylene glycol) + water aqueous two-phase system. The partition coefficients of the amino acids and peptides are aorrelated using the osmotic virial equation. The interaction coefficients contained in the equation can be calculated by hydrophilic group parameters. The partition coefficients of {alpha}-amylase calculated by the osmotic virial equation with the hydrophilic group parameters are in fairly good agreement with the experimental data, though a relatively large discrepancy is shown for {beta}-amylase. (author)

  14. Partition Coefficients of Amino Acids, Peptides, and Enzymes in Dextran + Poly(Ethylene Glycol) + Water Aqueous Two-Phase Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kakisaka, Keijiro.; Shindo, Takashi.; Iwai, Yoshio.; Arai, Yasuhiko. (Kyushu University, Fukuoka (Japan). Department of Chemical Systems and Engineering)

    1998-12-01

    Partition coefficients are measured for five amino acids(aspartic acid, asparagine, methionine, cysteine and histidine) and tow peptides(glycyl-glycine and hexa-glycine) in dextran + poly(ethylene glycol) + water aqueous two-phase system. The partition coefficients of the amino acids and peptides are aorrelated using the osmotic virial equation. The interaction coefficients contained in the equation can be calculated by hydrophilic group parameters. The partition coefficients of [alpha]-amylase calculated by the osmotic virial equation with the hydrophilic group parameters are in fairly good agreement with the experimental data, though a relatively large discrepancy is shown for [beta]-amylase. (author)

  15. Effect of the Polymeric Stabilizer in the Aqueous Phase Fischer-Tropsch Synthesis Catalyzed by Colloidal Cobalt Nanocatalysts

    Directory of Open Access Journals (Sweden)

    Jorge A. Delgado

    2017-03-01

    Full Text Available A series of small and well defined cobalt nanoparticles were synthesized by the chemical reduction of cobalt salts in water using NaBH4 as a reducing agent and using various polymeric stabilizers. The obtained nanocatalysts of similar mean diameters (ca. 2.6 nm were fully characterized and tested in the aqueous phase Fischer-Tropsch Synthesis (AFTS. Interestingly, the nature and structure of the stabilizers used during the synthesis of the CoNPs affected the reduction degree of cobalt and the B-doping of these NPs and consequently, influenced the performance of these nanocatalysts in AFTS.

  16. Hydroxyapatite-based sorbents: elaboration, characterization and application for the removal of catechol from the aqueous phase.

    Science.gov (United States)

    Sebei, Haroun; Pham Minh, Doan; Lyczko, Nathalie; Sharrock, Patrick; Nzihou, Ange

    2017-10-01

    Hydroxyapatite (HAP) is highly considered as good sorbent for the removal of metals from the aqueous phase. However, soluble metals co-exist with organic pollutants in wastewaters. But little work has been devoted to investigate the reactivity of HAP for the removal of organic compounds. The main objective of this work is to study the reactivity of HAP-based sorbents for the removal of catechol as a model organic pollutant from an aqueous solution. Thus, HAP sorbents were firstly synthesized using calcium carbonate and potassium dihydrogen phosphate under moderate conditions (25-80°C, atmospheric pressure). A zinc-doped HAP was also used as sorbent, which was obtained from the contact of HAP with an aqueous solution of zinc nitrate. All the sorbents were characterized by different standard physico-chemical techniques. The sorption of catechol was carried out in a batch reactor under stirring at room temperature and pressure. Zinc-doped HAP sorbent was found to be more reactive than non-doped HAP sorbents for the fixation of catechol. The highest sorption capacity was of 15 mg of C per gram of zinc-doped HAP sorbent. The results obtained suggest the reaction scheme of HAP sorbents with metals and organic pollutants when HAP sorbents were used for the treatment of complex wastewaters.

  17. Aqueous dispersion of monodisperse magnetic iron oxide nanocrystals through phase transfer

    International Nuclear Information System (INIS)

    Yu, William W; Chang, Emmanuel; Sayes, Christie M; Drezek, Rebekah; Colvin, Vicki L

    2006-01-01

    A facile method was developed for completely transferring high quality monodisperse iron oxide nanocrystals from organic solvents to water. The as-prepared aqueous dispersions of iron oxide nanocrystals were extremely stable and could be functionalized for bioconjugation with biomolecules. These iron oxide nanocrystals showed negligible cytotoxicity to human breast cancer cells (SK-BR-3) and human dermal fibroblast cells. This method is general and versatile for many organic solvent-synthesized nanoparticles, including fluorescent semiconductor nanocrystals

  18. Temperature-induced phase transition in aqueous solutions of poly(N-isopropylacrylamide)-based block copolymer

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří; Konefal, Rafal; Dybal, Jiří

    2016-01-01

    Roč. 369, č. 1 (2016), s. 92-96 ISSN 1022-1360. [International IUPAC Conference on Polymer-Solvent Complexes and Intercalates /11./ - POLYSOLVAT-11. Kolkata, 27.01.2016-30.01.2016] R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:61389013 Keywords : aqueous solutions * block copolymers * micelles Subject RIV: CD - Macromolecular Chemistry

  19. Influence of the composition of the aqueous phase on the behavior of the system FeCl3-HCl-DPE

    International Nuclear Information System (INIS)

    Ramirez, F. de M.; Jimenez-Reyes, M.

    1981-07-01

    We studied the influence of the aqueous phase composition upon an extraction system in which, at room temperature (20 0 C +- 3 0 C) using the dissolvents FeCl 3 -HCl-di-isopropyl ether the third phase phenomena is present after one minute of agitation. Our results showed that principally the hydrochloric acid dissolvent produced each of the three phases at given concentration levels as well as determined the nature of the chemical composition in each phase. (author)

  20. Phase Equilibria Prediction for Systems Containing Lipids

    DEFF Research Database (Denmark)

    Ana Perederic, Olivia; Cunico, Larissa; Sarup, Bent

    ]. Such developments have led to new challenges regarding the design anddevelopment of better performing processes and products. Despite the advances in propertymodelling and process design techniques available via different computeraidedmethods andtools for the chemical and petrochemical industries, the oleochemical...

  1. Phase equilibria at the Zirconium metal purification

    International Nuclear Information System (INIS)

    Dwiretnani-Sudjoko; Busron-Masduki; Sunardjo; Budi-Sulistyo

    1996-01-01

    It was investigated the research in the purification of zirconium metal, which was results from the reduction process, by adding heat in the vacuum environment. The process was done in batch in the stainless steel reactor, equiped with vacuum pump and electric heater. The investigated variable were process temperature and pressure. From this research it was obtained that equilibrium constant for MgCl 2 and Mg were expressed in the equation K M g C l 2 = 0.9011 P 1 .3779 1.06552 T and K M g = 6.0115P + 1.35256T - 6.93912

  2. Modeling of Phase Equilibria Containing Associating Fluids

    DEFF Research Database (Denmark)

    Derawi, Samer; Kontogeorgis, Georgios

    . The background and main targets for this thesis are presented in Chapter 1. In Chapter 2, a comprehensive review of the application of group contribution (GC) models such as various forms of UNIFAC and the so-called AFC (Atom and Fragment Contributions) correlation model for Pow (octanol-water partition...

  3. Phase Equilibria for Complex Polymer Solutions

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Hestkjær, L. L.; Hansen, A. F.

    2002-01-01

    the content of organic solvents. This work presents an investigation of the three polymer models Entropic-FV (EFV). UNIFAC-FV (UFV) and GC-Flory (GCF) for their capability of predicting solvent activity coefficients in binary systems containing complex polymers. It is possible to obtain good predictions...... at finite concentrations and satisfactory predictions at infinite dilution, particularly with the EFV model. The investigation shows that EFV is the most robust and stable of the models, which indicates that it is the most well suited model for further development of methods for predicting the miscibility...

  4. Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xueqin; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Zeng, Qun; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-03-01

    Graphical abstract: - Highlights: • A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized. • Functional guanidinium ionic liquid aqueous two-phase systems have been first designed for the purification of protein. • Mechanisms and performances of the process were researched. • Simple, green, safety and presents better purified ability than ordinary process. • A potential efficient platform for protein purification and related studies. - Abstract: A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV–vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV–vis spectrophotometer, Fourier-transform infrared

  5. Stability of relative equilibria of three vortices

    DEFF Research Database (Denmark)

    Aref, Hassan

    2009-01-01

    Three point vortices on the unbounded plane have relative equilibria wherein the vortices either form an equilateral triangle or are collinear. While the stability analysis of the equilateral triangle configurations is straightforward, that of the collinear relative equilibria is considerably mor...

  6. Strong Nash Equilibria and the Potential Maimizer

    NARCIS (Netherlands)

    van Megen, F.J.C.; Facchini, G.; Borm, P.E.M.; Tijs, S.H.

    1996-01-01

    A class of non cooperative games characterized by a `congestion e ect' is studied, in which there exists a strong Nash equilibrium, and the set of Nash equilibria, the set of strong Nash equilibria and the set of strategy pro les maximizing the potential function coincide.The structure of the class

  7. Theoretical study of phase behaviour of DLVO model for lysozyme and γ-crystalline aqueous electrolyte solutions

    Directory of Open Access Journals (Sweden)

    R. Melnyk

    2015-03-01

    Full Text Available Mean spherical approximation (MSA, second-order Barker-Henderson (BH perturbation theory and thermodynamic perturbation theory (TPT for associating fluids in combination with BH perturbation theory are applied to the study of the structural properties and phase behaviour of the Derjaguin-Landau-Verwey-Overbeek (DLVO model of lysozyme and γ-cristalline aqueous electrolyte solutions. Predictions of the MSA for the structure factors are in good agreement with the corresponding computer simulation predictions. The agreement between theoretical results for the liquid-gas phase diagram and the corresponding results of the experiment and computer simulation is less satisfactory, with predictions of the combined BH-TPT approach being the most accurate.

  8. Extraction of actinide and lanthanide complexonates in two-phase aqueous system potassium carbonate-polyethylene glycol-water

    International Nuclear Information System (INIS)

    Molochnikova, N.P.; Shkinev, V.M.; Spivakov, B.Ya.; Zolotov, Yu.A.; Myasoedov, B.F.

    1988-01-01

    Extraction system on the basis of polyethylene glycol for the concentration, isolation and separation of actinides is suggested. Extraction of actinides and lanthanides in two-phase aqueous system: potassium carbonate - polyethylene glycol - water in the presence of different complexones is investigated. Trivalent actinides are extracted quantitatively by polyethylene glycol from potassium carbonate solutions in the system with xylenol orange and alizarin-complexone. Under the conditions uranium (6) and plutonium (4) are extracted into the phase, enriched by polyethylene glycol, quite insignificantly, which permits to separate them from trivalent actinides with the separation factor of 10 2 - 10 3 . For actinide and lanthanide separation two complexones were introduced into the system, one of them being extractant, the other one - camouflaging reactant. The best results are obtained for the mixture of xylenol orange and hydroxyethylenediphosphonic acid. Separation coefficients for americium and europium constitute 4.5 - 5.6

  9. A propofol microemulsion with low free propofol in the aqueous phase: formulation, physicochemical characterization, stability and pharmacokinetics.

    Science.gov (United States)

    Cai, WeiHui; Deng, WanDing; Yang, HuiHui; Chen, XiaoPing; Jin, Fang

    2012-10-15

    The purpose of this study was to develop a propofol microemulsion with a low concentration of free propofol in the aqueous phase. Propofol microemulsions were prepared based on single-factor experiments and orthogonal design. The optimal microemulsion was evaluated for pH, osmolarity, particle size, zeta potential, morphology, free propofol in the aqueous phase, stability, and pharmacokinetics in beagle dogs, and comparisons made with the commercial emulsion, Diprivan(®). The pH and osmolarity of the microemulsion were similar to those of Diprivan(®). The average particle size was 22.6±0.2 nm, and TEM imaging indicated that the microemulsion particles were spherical in appearance. The concentration of free propofol in the microemulsion was 21.3% lower than that of Diprivan(®). Storage stability tests suggested that the microemulsion was stable long-term under room temperature conditions. The pharmacokinetic profile for the microemulsion showed rapid distribution and elimination compared to Diprivan(®). We conclude that the prepared microemulsion may be clinically useful as a potential carrier for propofol delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Distribution equilibria of Eu(III) in the system: bis(2-ethylhexyl)phosphoric acid organic diluent-NaCl, lactic acid, polyaminocarboxylic acid, water

    International Nuclear Information System (INIS)

    Danesi, P.R.; Cianetti, C.; Horwitz, E.P.

    1982-01-01

    The distribution equilibria of Eu 3+ between aqueous phases containing lactic acid and N'-(2hydroxyethyl)ethylenediamine-N,N,N'-triacetic acid (HEDTA) or diethylenetriamine-N,N,N',N',N''-penetaacetic acid (DTPA) at constant ionic strength (μ = 1.0), and n-dodecane solutions of HDEHP have been studied. The formation constants of the simple Eu-lactate complexes and Eu-lactate-HEDTA mixed complex were evaluated from the k/sub d/ data. The conclusion is reached that no lactic acid is coextracted into the organic phase at tracer metal concentrations. The separation factors between Eu 3+ , Pm 3+ , and Am 3+ have been evaluated in the presence of HEDTA

  11. Studies of Redox Equilibria at Elevated Temperatures 3. Oxide/oxide and Oxide/metal Couples of Iron, Nickel, Copper, Silver. Mercury and Antimony in Aqueous Systems up to 100 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Karin; Johnsson, Kerstin; Lewis, Derek

    1973-08-15

    Redox couples formed with Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4}, FeO{sub 2}H/Fe{sub 3}O{sub 4}, NiO/Ni, Cu{sub 2}O/Cu, Ag{sub 2}O/Ag, HgO/Hg and Sb{sub 2}O{sub 3}/Sb, in borax buffer solution have been studied at temperatures up to 100 deg C. The composition and morphology of the solid phases were characterized by X-ray diffraction measurements and electron micrography. Electrodes were formed with beds of mixtures of the solids through which the electrolyte was slowly perculated, and their potentials were measured relative to the hydrogen electrode. The results show that, in weakly alkaline solutions, systems including these couples only slowly attain electrochemical equilibrium. In the case of the iron couples at 25 deg C, for example, an emf with a long-term stability within 0.1 mV is not attained until after more than eight days equilibration: At higher temperatures a stable emf is attained more rapidly. All of the electrodes except the NiO/Ni electrode seem to be reversible but only the HgO/Hg electrode and, perhaps, the Cu{sub 2}O/Cu and Ag{sub 2}O/Ag electrodes, are likely to be useful at elevated temperatures. The apparent equilibrium constants found for the electrode reactions are compared with the theoretical values

  12. Derivatisation/solid-phase microextraction followed by gas chromatography-mass spectrometry for the analysis of phenoxy acid herbicides in aqueous samples

    DEFF Research Database (Denmark)

    Nilsson, Torben; Baglio, Daniela; Galdo-Miguez, Isabel

    1998-01-01

    Different combinations of derivatisation and solid-phase microextraction followed by gas chromatography-mass spectrometry were optimised and evaluated for the analysis of phenoxy acid herbicides in water. The most successful derivatisation approach was aqueous-phase derivatisation with benzyl...

  13. Triton X-114 based cloud point extraction: a thermoreversible approach for separation/concentration and dispersion of nanomaterials in the aqueous phase.

    Science.gov (United States)

    Liu, Jing-fu; Liu, Rui; Yin, Yong-guang; Jiang, Gui-bin

    2009-03-28

    Capable of preserving the sizes and shapes of nanomaterials during the phase transferring, Triton X-114 based cloud point extraction provides a general, simple, and cost-effective route for reversible concentration/separation or dispersion of various nanomaterials in the aqueous phase.

  14. Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein.

    Science.gov (United States)

    Ding, Xueqin; Wang, Yuzhi; Zeng, Qun; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-03-07

    A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by (1)H nuclear magnetic resonance ((1)H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV-vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV-vis spectrophotometer, Fourier-transform infrared spectroscopy (FT-IR) and circular dichroism spectrum (CD spectrum). The precision, stability and repeatability of the process were investigated. The mechanisms of purification were researched by dynamic light scattering (DLS), determination of the conductivity and transmission electron microscopy (TEM). It was suggested that aggregation and embrace phenomenon play a significant role in the purification of proteins. All the results show that FGIL-ATPSs have huge potential to offer new possibility in the purification of proteins. Copyright © 2014 Elsevier B.V. All rights

  15. Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    B. D. Castro

    2005-09-01

    Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.

  16. Some aspects of the formation of the dispersed phase in aqueous solutions

    International Nuclear Information System (INIS)

    Ershov, B.G.; Sukhov, N.L.; Troitskii, D.I.

    1992-01-01

    The experimental results on the formation of silver colloids and some insoluble salts in aqueous solutions are discussed. Colloidal silver particles are formed as a result of radiation-chemical reduction of Ag + ions in deaerated solution containing alcohols or formic acid. Subcolloidal species containing 12-16 atoms are the precursors of the metal sol. The rate of nucleation increases with increasing concentration of indifferent electrolyte (NaClO 4 ) in solution as a result of the change in the ionic strength. Some anions such as sulphate, formate and others are chemisorbed on the subcolloidal silver surfaces, which dramatically decreases their stability. (author)

  17. KEMOD: A mixed chemical kinetic and equilibrium model of aqueous and solid phase geochemical reactions

    International Nuclear Information System (INIS)

    Yeh, G.T.; Iskra, G.A.

    1995-01-01

    This report presents the development of a mixed chemical Kinetic and Equilibrium MODel in which every chemical species can be treated either as a equilibrium-controlled or as a kinetically controlled reaction. The reaction processes include aqueous complexation, adsorption/desorption, ion exchange, precipitation/dissolution, oxidation/reduction, and acid/base reactions. Further development and modification of KEMOD can be made in: (1) inclusion of species switching solution algorithms, (2) incorporation of the effect of temperature and pressure on equilibrium and rate constants, and (3) extension to high ionic strength

  18. Signaling equilibria in sensorimotor interactions.

    Science.gov (United States)

    Leibfried, Felix; Grau-Moya, Jordi; Braun, Daniel A

    2015-08-01

    Although complex forms of communication like human language are often assumed to have evolved out of more simple forms of sensorimotor signaling, less attention has been devoted to investigate the latter. Here, we study communicative sensorimotor behavior of humans in a two-person joint motor task where each player controls one dimension of a planar motion. We designed this joint task as a game where one player (the sender) possesses private information about a hidden target the other player (the receiver) wants to know about, and where the sender's actions are costly signals that influence the receiver's control strategy. We developed a game-theoretic model within the framework of signaling games to investigate whether subjects' behavior could be adequately described by the corresponding equilibrium solutions. The model predicts both separating and pooling equilibria, in which signaling does and does not occur respectively. We observed both kinds of equilibria in subjects and found that, in line with model predictions, the propensity of signaling decreased with increasing signaling costs and decreasing uncertainty on the part of the receiver. Our study demonstrates that signaling games, which have previously been applied to economic decision-making and animal communication, provide a framework for human signaling behavior arising during sensorimotor interactions in continuous and dynamic environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Formation of aqueous-phase sulfate during the haze period in China: Kinetics and atmospheric implications

    Science.gov (United States)

    Zhang, Haijie; Chen, Shilu; Zhong, Jie; Zhang, Shaowen; Zhang, Yunhong; Zhang, Xiuhui; Li, Zesheng; Zeng, Xiao Cheng

    2018-03-01

    Sulfate is one of the most important components in the aerosol due to its key role in air pollution and global climate change. Recent work has suggested that reactive nitrogen chemistry in aqueous water can explain the missing source of sulfate in the aqueous water. Herein, we have mapped out the energy profile of the oxidization process of SO2 leading from NO2 and two feasible three-step mechanisms have been proposed. For the oxidation of HOSO2- and HSO3- by the dissolved NO2 in weakly acidic and neutral aerosol (pH ≤ 7), the main contribution to the missing sulfate production comes from the oxidation of HOSO2-. The whole process is a self-sustaining process. For the oxidation of SO32- in alkaline aerosol (pH > 7), the third step - decomposition step of H2O or hydrolysis of SO3 step which are two parallel processes are the rate-limiting steps. The present results are of avail to better understand the missing source of sulfate in the aerosol and hence may lead to better science-based solutions for resolving the severe haze problems in China.

  20. Metal Oxide-Carbon Nanocomposites for Aqueous and Nonaqueous Supercapacitors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I effort focuses on development of novel metal-oxide-carbon nanocomposites for application in pseudocapacitive...