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Sample records for binary ionic mixtures

  1. Viscosity and mutual diffusion in strongly asymmetric binary ionic mixtures

    CERN Document Server

    Bastea, S

    2005-01-01

    We present molecular dynamics simulation results for the viscosity and mutual diffusion constant of a strongly asymmetric binary ionic mixture (BIM). We compare the results with available theoretical models previously tested for much smaller asymmetries. For the case of viscosity we propose a new predictive framework based on the linear mixing rule, while for mutual diffusion we discuss some consistency problems of widely used Boltzmann equation based models.

  2. Effective Potential Theory for Diffusion in Binary Ionic Mixtures

    CERN Document Server

    Shaffer, Nathaniel R; Daligault, Jérôme

    2016-01-01

    Self-diffusion and interdiffusion coefficients of binary ionic mixtures are evaluated using the Effective Potential Theory (EPT), and the predictions are compared with the results of molecular dynamics simulations. We find that EPT agrees with molecular dynamics from weak coupling well into the strong coupling regime, which is a similar range of coupling strengths as previously observed in comparisons with the one-component plasma. Within this range, typical relative errors of approximately 20% and worst-case relative errors of approximately 40% are observed. We also examine the Darken model, which approximates the interdiffusion coefficients based on the self-diffusion coefficients.

  3. Effective Potential and Interdiffusion in Binary Ionic Mixtures

    CERN Document Server

    Beznogov, M V

    2014-01-01

    We calculate interdiffusion coefficients in a two-component, weakly or strongly coupled ion plasma (gas or liquid, composed of two ion species immersed into a neutralizing electron background). We use an effective potential method proposed recently by Baalrud and Daligaut [PRL, 110, 235001, (2013)]. It allows us to extend the standard Chapman-Enskog procedure of calculating the interdiffusion coefficients to the case of strong Coulomb coupling. We compute binary diffusion coefficients for several ionic mixtures and fit them by convenient expressions in terms of the generalized Coulomb logarithm. These fits cover a wide range of plasma parameters spanning from weak to strong Coulomb couplings. They can be used to simulate diffusion of ions in ordinary stars as well as in white dwarfs and neutron stars.

  4. Linear mixing rule in screened binary ionic mixtures

    Science.gov (United States)

    Chabrier, G.; Ashcroft, N. W.

    1990-01-01

    The validity of the linear mixing rule is examined for the following two cases (1) when the response of the electron gas is taken into account in the effective ionic interaction and (2) when finite-temperature effects are included in the dielectric response of the electrons, i.e., when the ions interact with both temperature- and density-dependent screened Coulomb potentials. It is found that the linear mixing rule remains valid when the electron response is taken into account in the interionic potential at any density, even though the departure from linearity can reach a few percent for the asymmetric mixtures in the region of weak degeneracy for the electron gas. A physical explanation of this behavior is proposed which is based on a simple additional length scale.

  5. Solid–liquid equilibria of binary mixtures of fluorinated ionic liquids†

    Science.gov (United States)

    Teles, Ana Rita R.; Correia, Helga; Maximo, Guilherme J.; Rebelo, Luís P. N.; Freire, Mara G.; Pereiro, Ana B.; Coutinho, João A. P.

    2016-01-01

    Within ionic liquids, fluorinated ionic liquids (FILs) present unique physico-chemical properties and potential applications in several fields. However, the melting point of these neoteric compounds is usually higher due to the presence of fluorine atoms. This drawback may be resolved by, for instance, mixing different FILs to create eutectic mixtures. In this work, binary mixtures of fluoro-containing and fluorinated ionic liquids were considered with the aim of decreasing their melting temperatures as well as understanding and characterizing these mixtures and their phase transitions. Five FILs were selected, allowing the investigation of four binary mixtures, each of them with a common ion. Their solid–liquid and solid–solid equilibria were studied by differential scanning calorimetry and the non-ideality of the mixtures was investigated. Overall, a variety of solid–liquid equilibria with systems exhibiting eutectic behavior, polymorphs with solid–solid phase transitions, and the formation of intermediate compounds and solid solutions were surprisingly found. In addition to these intriguing behaviours, novel FILs with lower melting temperatures were obtained by the formation of binary systems, thus enlarging the application range of FILs at lower temperatures. PMID:27603428

  6. Solid-liquid equilibria of binary mixtures of fluorinated ionic liquids.

    Science.gov (United States)

    Teles, Ana Rita R; Correia, Helga; Maximo, Guilherme J; Rebelo, Luís P N; Freire, Mara G; Pereiro, Ana B; Coutinho, João A P

    2016-09-28

    Within ionic liquids, fluorinated ionic liquids (FILs) present unique physico-chemical properties and potential applications in several fields. However, the melting point of these neoteric compounds is usually higher due to the presence of fluorine atoms. This drawback may be resolved by, for instance, mixing different FILs to create eutectic mixtures. In this work, binary mixtures of fluoro-containing and fluorinated ionic liquids were considered with the aim of decreasing their melting temperatures as well as understanding and characterizing these mixtures and their phase transitions. Five FILs were selected, allowing the investigation of four binary mixtures, each of them with a common ion. Their solid-liquid and solid-solid equilibria were studied by differential scanning calorimetry and the non-ideality of the mixtures was investigated. Overall, a variety of solid-liquid equilibria with systems exhibiting eutectic behavior, polymorphs with solid-solid phase transitions, and the formation of intermediate compounds and solid solutions were surprisingly found. In addition to these intriguing behaviours, novel FILs with lower melting temperatures were obtained by the formation of binary systems, thus enlarging the application range of FILs at lower temperatures.

  7. Volumetric properties of binary mixtures of benzene with cyano-based ionic liquids

    Science.gov (United States)

    Gonfa, Girma; Bustam, Mohamad Azmi; Moniruzzaman, Muhammad; Murugesan, Thanabalan

    2014-10-01

    The objective of this study is to investigate the volumetric properties of the binary mixtures comprised benzene and two ionic liquids, 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) and 1-butyl-3-methyl- imidazolium dicyanamide ([ BMIM ][ N ( CN )2]( . Densities (ρ) and viscosities (μ) of the binary mixtures were measured over a temperature range of 293.15 to 323.15 K and at atmospheric pressure. Excess molar volumes and viscosity deviations were calculated from the experimental densities and viscosities values. The volumetric properties of the mixtures were changed significantly with the change of compositions and temperatures. It was also found that the value of excess molar volume and viscosity deviations were negative (-ve) over the entire range of compositions. The results have been interpreted in terms of molecular interactions of ILs and benzene.

  8. True molecular solutions of natural cellulose in the binary ionic liquid-containing solvent mixtures.

    Science.gov (United States)

    Rein, Dmitry M; Khalfin, Rafail; Szekely, Noemi; Cohen, Yachin

    2014-11-04

    Evidence is presented for the first time of true molecular dissolution of cellulose in binary mixtures of common polar organic solvents with ionic liquid. Cryogenic transmission electron microscopy, small-angle neutron-, X-ray- and static light scattering were used to investigate the structure of cellulose solutions in mixture of dimethyl formamide and 1-ethyl-3-methylimidazolium acetate. Structural information on the dissolved chains (average molecular weight ∼ 5 × 10(4)g/mol; gyration radius ∼ 36 nm, persistence length ∼ 4.5 nm), indicate the absence of significant aggregation of the dissolved chains and the calculated value of the second virial coefficient ∼ 2.45 × 10(-2)mol ml/g(2) indicates that this solvent system is a good solvent for cellulose. More facile dissolution of cellulose could be achieved in solvent mixtures that exhibit the highest electrical conductivity. Highly concentrated cellulose solution in pure ionic liquid (27 wt.%) prepared according to novel method, utilizing the rapid evaporation of a volatile co-solvent in binary solvent mixtures at superheated conditions, shows insignificant cellulose molecular aggregation.

  9. The susceptibility critical exponent for a nonaqueous ionic binary mixture near a consolute point

    Science.gov (United States)

    Zhang, Kai C.; Briggs, Matthew E.; Gammon, Robert W.; Levelt Sengers, J. M. H.

    1992-01-01

    We report turbidity measurements of a nonaqueous ionic solution of triethyl n-hexylammonium triethyl n-hexylboride in diphenyl ether. A classical susceptibility critical exponent gamma = 1.01 +/- 0.01 is obtained over the reduced temperature range t between values of 0.1 and 0.0001. The best fits of the sample transmission had a standard deviation of 0.39 percent over this range. Ising and spherical model critical exponents are firmly excluded. The correlation length amplitude xi sub 0 from fitting is 1.0 +/- 0.2 nm which is much larger than values found in neutral fluids and some aqueous binary mixtures.

  10. Features of non-congruent phase transition in modified Coulomb model of the binary ionic mixture

    Science.gov (United States)

    Stroev, N. E.; Iosilevskiy, I. L.

    2016-11-01

    Non-congruent gas-liquid phase transition (NCPT) have been studied previously in modified Coulomb model of a binary ionic mixture C(+6) + O(+8) on a uniformly compressible ideal electronic background /BIM(∼)/. The features of NCPT in improved version of the BIM(∼) model for the same mixture on background of non-ideal electronic Fermi-gas and comparison it with the previous calculations are the subject of present study. Analytical fits for Coulomb corrections to equation of state of electronic and ionic subsystems were used in present calculations within the Gibbs-Guggenheim conditions of non-congruent phase equilibrium. Parameters of critical point-line were calculated on the entire range of proportions of mixed ions 0 BIM(∼) model. Just similar distillation was obtained in the variant of NCPT in dense nuslear matter. The absence of azeotropic compositions was revealed in studied variants of BIM(∼) in contrast to an explicit existence of the azeotropic compositions for the NCPT in chemically reacting plasmas and in astrophysical applications.

  11. Features of non-congruent phase transition in modified Coulomb model of the binary ionic mixture

    CERN Document Server

    Stroev, N E

    2016-01-01

    Non-congruent gas-liquid phase transition (NCPT) have been studied in modified Coulomb model of a binary ionic mixture C(+6) + O(+8) on a \\textit{uniformly compressible} ideal electronic background /BIM($\\sim$)/. The features of NCPT in improved version of the BIM($\\sim$) model for the same mixture on background of \\textit{non-ideal} electronic Fermi-gas and comparison it with the previous calculations are the subject of present study. Analytical fits for Coulomb corrections to EoS of electronic and ionic subsystems were used in present calculations within the Gibbs--Guggenheim conditions of non-congruent phase equilibrium.Parameters of critical point-line (CPL) were calculated on the entire range of proportions of mixed ions $0

  12. Dielectric relaxation in ionic liquid/dipolar solvent binary mixtures: A semi-molecular theory

    Science.gov (United States)

    Daschakraborty, Snehasis; Biswas, Ranjit

    2016-03-01

    A semi-molecular theory is developed here for studying dielectric relaxation (DR) in binary mixtures of ionic liquids (ILs) with common dipolar solvents. Effects of ion translation on DR time scale, and those of ion rotation on conductivity relaxation time scale are explored. Two different models for the theoretical calculations have been considered: (i) separate medium approach, where molecularities of both the IL and dipolar solvent molecules are retained, and (ii) effective medium approach, where the added dipolar solvent molecules are assumed to combine with the dipolar ions of the IL, producing a fictitious effective medium characterized via effective dipole moment, density, and diameter. Semi-molecular expressions for the diffusive DR times have been derived which incorporates the effects of wavenumber dependent orientational static correlations, ion dynamic structure factors, and ion translation. Subsequently, the theory has been applied to the binary mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) with water (H2O), and acetonitrile (CH3CN) for which experimental DR data are available. On comparison, predicted DR time scales show close agreement with the measured DR times at low IL mole fractions (xIL). At higher IL concentrations (xIL > 0.05), the theory over-estimates the relaxation times and increasingly deviates from the measurements with xIL, deviation being the maximum for the neat IL by almost two orders of magnitude. The theory predicts negligible contributions to this deviation from the xIL dependent collective orientational static correlations. The drastic difference between DR time scales for IL/solvent mixtures from theory and experiments arises primarily due to the use of the actual molecular volume ( Vmol dip ) for the rotating dipolar moiety in the present theory and suggests that only a fraction of Vmol dip is involved at high xIL. Expectedly, nice agreement between theory and experiments appears when experimental

  13. Dielectric relaxation in ionic liquid/dipolar solvent binary mixtures: A semi-molecular theory.

    Science.gov (United States)

    Daschakraborty, Snehasis; Biswas, Ranjit

    2016-03-14

    A semi-molecular theory is developed here for studying dielectric relaxation (DR) in binary mixtures of ionic liquids (ILs) with common dipolar solvents. Effects of ion translation on DR time scale, and those of ion rotation on conductivity relaxation time scale are explored. Two different models for the theoretical calculations have been considered: (i) separate medium approach, where molecularities of both the IL and dipolar solvent molecules are retained, and (ii) effective medium approach, where the added dipolar solvent molecules are assumed to combine with the dipolar ions of the IL, producing a fictitious effective medium characterized via effective dipole moment, density, and diameter. Semi-molecular expressions for the diffusive DR times have been derived which incorporates the effects of wavenumber dependent orientational static correlations, ion dynamic structure factors, and ion translation. Subsequently, the theory has been applied to the binary mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) with water (H2O), and acetonitrile (CH3CN) for which experimental DR data are available. On comparison, predicted DR time scales show close agreement with the measured DR times at low IL mole fractions (x(IL)). At higher IL concentrations (x(IL) > 0.05), the theory over-estimates the relaxation times and increasingly deviates from the measurements with x(IL), deviation being the maximum for the neat IL by almost two orders of magnitude. The theory predicts negligible contributions to this deviation from the x(IL) dependent collective orientational static correlations. The drastic difference between DR time scales for IL/solvent mixtures from theory and experiments arises primarily due to the use of the actual molecular volume (V(mol)(dip)) for the rotating dipolar moiety in the present theory and suggests that only a fraction of V(mol)(dip) is involved at high x(IL). Expectedly, nice agreement between theory and experiments appears when

  14. Molecular Dynamics Simulation for the Binary Mixtures of High Pressure Carbon Dioxide and Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    徐君臣; 王松; 喻文; 徐琴琴; 王伟彬; 银建中

    2014-01-01

    Molecular dynamics simulation with an all-atom force field has been carried out on the two binary sys-tems of [bmim][PF6]-CO2 and [bmim][NO3]-CO2 to study the transport properties, volume expansion and micro-structures. It was found that addition of CO2 in the liquid phase can greatly decrease the viscosity of ionic liquids (ILs) and increase their diffusion coefficient obviously. Furthermore, the volume expansion of ionic liquids was found to increase with the increase of the mole fraction of CO2 in the liquid phase but less than 35%for the two simulated systems, which had a significant difference with CO2 expanded organic solvents. The main reason was that there were some void spaces inter and intra the molecules of ionic liquids. Finally, site to site radial distribution functions and corresponding number integrals were investigated and it was found that the change of microstructures of ILs by addition CO2 had a great influence on the properties of ILs.

  15. Thermodynamical and structural properties of binary mixtures of imidazolium chloride ionic liquids and alcohols from molecular simulation

    Science.gov (United States)

    Raabe, Gabriele; Köhler, Jürgen

    2008-10-01

    We have performed molecular dynamics simulations to determine the densities, excess energies of mixing, and structural properties of binary mixtures of the 1-alkyl-3-methylimidazolium chloride ionic liquids (ILs) [amim][Cl] and ethanol and 1-propanol in the temperature range from 298.15to363.15K. As in our previous work [J. Chem. Phys. 128, 154509 (2008)], our simulation studies are based on a united atom model from Liu et al. [Phys. Chem. Chem. Phys. 8, 1096 (2006)] for the 1-ethyl- and 1-butyl-3-methylimidazolium cations [emim+] and [bmim+], which we have extended to the 1-hexyl-3-methylimidazolium [hmim+] cation and combined with parameters of Canongia Lopes et al. [J. Phys. Chem. B 108, 2038 (2004)] for the chloride anion [Cl-] and the force field by Khare et al. for the alcohols [J. Phys. Chem. B 108, 10071 (2004)]. With this, we provide both prediction for the densities of the mixtures that have mostly not been investigated experimentally yet and a molecular picture of the interactions between the alcohol molecules and the ions. The negative excess energies of all mixtures indicate an energetically favorable mixing of [amim][Cl] ILs and alcohols. To gain insight into the nonideality of the mixtures on the molecular level, we analyzed their local structures by radial and spatial distribution functions. These analyses show that the local ordering in these mixtures is determined by strong hydrogen-bond interactions between the chloride anion and the hydroxyls of the alcohols, enhanced interactions between the anion and the charged domain of the cation, and an increasing aggregation of the nonpolar alkyl tails of the alcohols and the cations with increasing cation size, which results in a segregation of polar and nonpolar domains.

  16. Segregation of ions at the interface: molecular dynamics studies of the bulk and liquid-vapor interface structure of equimolar binary mixtures of ionic liquids.

    Science.gov (United States)

    Palchowdhury, Sourav; Bhargava, B L

    2015-08-14

    The structures of three different equimolar binary ionic liquid mixtures and their liquid-vapor interface have been studied using atomistic molecular dynamics simulations. Two of these binary mixtures were composed of a common cation 1-n-butyl-3-methylimidazolium and varying anions (chloride and hexafluorophosphate in one of the mixtures and chloride and trifluoromethanesulfonate in the other) and the third binary mixture was composed of a common anion, trifluoromethanesulfonate and two imidazolium cations with ethyl and octyl side chains. Binary mixtures with common cations are found to be homogeneous. The anions are preferentially located near the ring hydrogen atoms due to H-bonding interactions. Segregation of ions is observed at the interface with an enrichment of the liquid-vapor interface layer by longer alkyl chains and bigger anions with a distributed charge. The surface composition is drastically different from that of the bulk composition, with the longer alkyl tail groups and bigger anions populating the outermost layer of the interface. The longer alkyl chains of the cations and trifluoromethanesulfonate anions with a smaller charge density show orientational ordering at the liquid-vapor interface.

  17. Thermophysical properties of binary mixtures of {l_brace}ionic liquid 2-hydroxy ethylammonium acetate + (water, methanol, or ethanol){r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Victor H. [School of Chemical Engineering, State University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Chemical Engineering Department, ETSE, University of Santiago de Compostela (USC), P.O. Box 15782, Santiago de Compostela (Spain); Mattedi, Silvana [Chemical Engineering Department, Polytechnic School, Federal University of Bahia (UFBA), 40210-630 Salvador-BA (Brazil); Martin-Pastor, Manuel [Unidade de Resonancia Magnetica, RIAIDT, edif. CACTUS, University of Santiago de Compostela (USC), P.O. Box 15706, Santiago de Compostela (Spain); Aznar, Martin [School of Chemical Engineering, State University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Iglesias, Miguel, E-mail: miguel.iglesias@usc.es [Chemical Engineering Department, ETSE, University of Santiago de Compostela (USC), P.O. Box 15782, Santiago de Compostela (Spain)

    2011-07-15

    Research highlights: > This paper reports the density and speed of sound data of binary mixtures {l_brace}2-hydroxy ethylammonium acetate + (water, or methanol, or ethanol){r_brace} measured between the temperatures (298.15 and 313.15) K at atmospheric pressure. > The aggregation, dynamic behavior, and hydrogen-bond network were studied using thermo-acoustic, X-ray, and NMR techniques. > The Peng-Robinson equation of state, coupled with the Wong-Sandler mixing rule using the COSMO-SAC model predicted the density of the solutions with relative mean deviations below than 3.0%. - Abstract: In this work, density and speed of sound data of binary mixtures of an ionic liquid consisting of {l_brace}2-hydroxy ethylammonium acetate (2-HEAA) + (water, methanol, or ethanol){r_brace} have been measured throughout the entire concentration range, from the temperature of (288.15 to 323.15) K at atmospheric pressure. The excess molar volumes, variations of the isentropic compressibility, the apparent molar volume, isentropic apparent molar compressibility, and thermal expansion coefficient were calculated from the experimental data. The excess molar volumes were negative throughout the whole composition range. Compressibility data in combination with low angle X-ray scattering and NMR measurements proved that the presence of micelles formed due to ion pair interaction above a critical concentration of the ionic liquid in the mixtures. The Peng-Robinson equation of state coupled with the Wong-Sandler mixing rule and COSMO-SAC model was used to predict densities and the calculated deviations were lower than 3%, for binary mixtures in all composition range.

  18. Molecular dynamics study of nanoscale organization and hydrogen bonding in binary mixtures of butylammonium nitrate ionic liquid and primary alcohols

    Science.gov (United States)

    Shrivastav, Gourav; Gupta, Aditya; Rastogi, Aman; Dhabal, Debdas; Kashyap, Hemant K.

    2017-02-01

    Molecular dynamics simulations are utilized here to explore the nanoscale morphology and the nature of hydrogen bonding in the equimolar mixtures of butylammonium nitrate protic ionic liquid with ethanol, propanol, and butanol. The X-ray scattering experimental study of Greaves et al. [Phys. Chem. Chem. Phys. 13, 13 501 (2011)] has evidenced that alkylammonium nitrate plus alcohol mixtures possess nanoscale structural order which becomes more pronounced as the chain length of the alcohol increases. Our analysis carried out using simulated total and partial X-ray scattering structure functions quantifies the basis of these observations. The partial structure functions highlight the off-phase density correlations of alcohol with both cation and anion in the low-q region. We demonstrate that the chain lengthening of alcohols offers significant variation in the structuring of the polar and apolar moieties in the mixtures. The inspection based on radial distribution functions manifests the non-linear hydrogen bonds of cations with nitrate anions as well as alcohol molecules. The alcohol's hydroxyl group prefers to form linear hydrogen bonds with anions and with other alcohol molecules. Incremented chain length of alcohol improves the extent of hydrogen bonding but does not alter their geometry. Spatial distribution functions delineate similar preferences. It shows stronger directional preferences of the hydroxyl group of alcohols than cation in the vicinity of an anion. Enhanced pair correlations associated with the terminal methyl carbons suggest aggregation of butanol chains in apolar domains. Triplet correlation functions (TCFs) are also used to evaluate the orientational preferences of the present polar moieties in the mixtures. Information based on TCFs for distribution of polar head group of cations and anions unveils the dominance of equilateral configurations over the less frequent isosceles configurations in all the three mixtures.

  19. An experimental observation of the different behavior of ionic and neutral lines of iron as a function of number density in a binary carbon–iron mixture

    Energy Technology Data Exchange (ETDEWEB)

    Sivakumar, P.; Taleh, L.; Markushin, Y. [Optical Science Center for Applied Research and Applications, Department of Physics and Pre-Engineering, Delaware State University, Dover, DE 19901 (United States); Melikechi, N., E-mail: nmelikechi@desu.edu [Optical Science Center for Applied Research and Applications, Department of Physics and Pre-Engineering, Delaware State University, Dover, DE 19901 (United States); Lasue, J. [Université de Toulouse, UPS-OMP, IRAP, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); ISR, MS D466, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058 (United States)

    2013-04-01

    We report on the dependence of the intensities of atomic and ionic lines emitted by a nanosecond laser-induced plasma on the atomic number densities of the constituents of a binary mixture formed of carbon and iron. We show that the packing density of the sample greatly affects the relative standard deviation of the emission lines. Furthermore, we show that the variation of the intensities of the C and Fe emission lines depends in a non-trivial way on the relative C–Fe concentration. The intensities of Fe neutral atomic lines behave differently than those of the ionic ones particularly at and above concentrations of 75%–80% Fe embedded in a carbon matrix. Unlike the emission from neutral Fe, those from ionic Fe yield a very sharp decrease followed by an equally strong increase of the emission lines over a relatively small range of relative concentration of C and Fe. To better investigate this effect, we have compared the results obtained with nanosecond-LIBS to those with femtosecond-LIBS and found that this phenomenon disappears. The physical interpretation of the sharp decrease followed by an equally sharp increase in the emission intensities from Fe ions as the concentration of Fe is increased requires more studies. - Highlights: ► The effects of the size of the particles on the fluctuations of the LIBS signals ► The variation of LIBS signals with the concentrations of Fe embedded in C is nontrivial. ► The intensities of neutral atomic lines can behave differently than those of ions.

  20. Marangoni Convection in Binary Mixtures

    CERN Document Server

    Zhang, J; Oron, A; Behringer, Robert P.; Oron, Alexander; Zhang, Jie

    2006-01-01

    Marangoni instabilities in binary mixtures are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of sodium chloride/water, we have systematically investigated the pattern formation for a set of substrate temperatures and solute concentrations in an open system. The flow patterns evolve with time, driven by surface-tension fluctuations due to evaporation and the Soret effect, while the air-liquid interface does not deform. A shadowgraph method is used to follow the pattern formation in time. The patterns are mainly composed of polygons and rolls. The mean pattern size first decreases slightly, and then gradually increases during the evolution. Evaporation affects the pattern formation mainly at the early stage and the local evaporation rate tends to become spatially uniform at the film surface. The Soret effect becomes i...

  1. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  2. Comparison of electrochemical methods for triiodide diffusion coefficient measurements and observation of non-Stokesian diffusion behaviour in binary mixtures of two ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Zistler, M.; Wachter, P.; Gores, H.J. [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Regensburg (Germany); Wasserscheid, P.; Gerhard, D. [Institut fuer Chemische Reaktionstechnik, Friedrich-Alexander-Universitaet, Erlangen-Nuernberg (Germany); Hinsch, A. [Fraunhofer Institute for Solar Energy Systems ISE, Freiburg (Germany). Department of Materials Research and Applied Optics; Sastrawan, R. [Freiburg Materials Research Center, Freiburg (Germany)

    2006-10-05

    Results of diffusion coefficient measurements of triiodide in a mixture of two ionic liquids (1-methyl-3-propylimidazolium iodide and 1-butyl-3-methylimidazolium tetrafluoroborate) at 25{sup o}C are described in this paper. Four electrochemical methods for measuring diffusion coefficients of triiodide were evaluated for their reliability and performance, including impedance spectroscopy and polarization measurements at thin layer cells as well as cyclic voltammetry and chronoamperometry at microelectrodes of different radii. Viscosities of the blends were measured to investigate the transport behaviour of triiodide ions used in Gratzel-type dye-sensitized solar cells. (author)

  3. Evaporative Instability in Binary Mixtures

    Science.gov (United States)

    Narayanan, Ranga; Uguz, Erdem

    2012-11-01

    In this talk we depict the physics of evaporative convection for binary systems in the presence of surface tension gradient effects. Two results are of importance. The first is that a binary system, in the absence of gravity, can generate an instability only when heated from the vapor side. This is to be contrasted with the case of a single component where instability can occur only when heated from the liquid side. The second result is that a binary system, in the presence of gravity, will generate an instability when heated from either the vapor or the liquid side provided the heating is strong enough. In addition to these results we show the conditions at which interfacial patterns can occur. Support from NSF OISE 0968313, Partner Univ. Fund and a Chateaubriand Fellowship is acknowledged.

  4. Behaviour of a binary solvent mixture constituted by an amphiphilic ionic liquid, 1-decyl-3-methylimidazolium bromide and water Potentiometric and conductimetric studies.

    Science.gov (United States)

    Sirieix-Plénet, Juliette; Gaillon, Laurent; Letellier, Pierre

    2004-07-01

    We investigated the properties of 1-decyl-3-methylimidazolium bromide (DMImBr), a molten salt at room temperature, and its mixtures with water in the whole proportions. At low concentrations, this salt behaved like a classical cationic amphiphile. Its critical micellar concentration (cmc) was determined by conductimetry and by measuring electromotive forces (EMF) with bromide or cationic surfactant-selective electrodes. Moreover, the association rate of the counter ion to micelle has been determined on a wide range of concentrations, allowing characterising the micellisation equilibrium by a solubility product. The conductivity of this liquid electrolyte in mixtures with water was maximal at high concentrations. We modelled this behaviour, taking into account the molar volume fraction of both phases. Our results show that these solutions, which are composed of dispersed aggregates, behave like mixtures of two phases that interpenetrate themselves.

  5. Spinodal decomposition of chemically reactive binary mixtures

    Science.gov (United States)

    Lamorgese, A.; Mauri, R.

    2016-08-01

    We simulate the influence of a reversible isomerization reaction on the phase segregation process occurring after spinodal decomposition of a deeply quenched regular binary mixture, restricting attention to systems wherein material transport occurs solely by diffusion. Our theoretical approach follows a diffuse-interface model of partially miscible binary mixtures wherein the coupling between reaction and diffusion is addressed within the frame of nonequilibrium thermodynamics, leading to a linear dependence of the reaction rate on the chemical affinity. Ultimately, the rate for an elementary reaction depends on the local part of the chemical potential difference since reaction is an inherently local phenomenon. Based on two-dimensional simulation results, we express the competition between segregation and reaction as a function of the Damköhler number. For a phase-separating mixture with components having different physical properties, a skewed phase diagram leads, at large times, to a system converging to a single-phase equilibrium state, corresponding to the absolute minimum of the Gibbs free energy. This conclusion continues to hold for the critical phase separation of an ideally perfectly symmetric binary mixture, where the choice of final equilibrium state at large times depends on the initial mean concentration being slightly larger or less than the critical concentration.

  6. Raman and ab initio studies of simple and binary 1-alkyl-3-methylimidazolium ionic liquids

    DEFF Research Database (Denmark)

    Berg, R.W.; Deetlefs, M.; Seddon, K.R.;

    2005-01-01

    Raman spectra of the ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF6]), 1-hexyl-3-methylimidazolium chloride ([C(6)mim]Cl), and 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)mim][PF6]), and binary mixtures thereof, have been assigned using ab initio MP2...

  7. Physicochemical Properties of Glycine-Based Ionic Liquid [QuatGly-OEt][EtOSO3] (2-Ethoxy-1-ethyl-1,1-dimethyl-2-oxoethanaminium ethyl sulfate and Its Binary Mixtures with Poly(ethylene glycol (Mw = 200 at Various Temperatures

    Directory of Open Access Journals (Sweden)

    Chung-Wen Kuo

    2011-12-01

    Full Text Available This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL [QuatGly-OEt][EtOSO3] by NMR, elementary analysis and water content. Thermophysical properties such as density, ρ, viscosity, η, refractive index, n, and conductivity, κ, for the binary mixture of [QuatGly-OEt][EtOSO3] with poly(ethylene glycol (PEG [Mw = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO3] and its binary mixture can be described by an empirical polynomial equation and by the Vogel-Tammann-Fucher (VTF equation, respectively. The thermal expansion coefficient of the ILs is ascertained using the experimental density results, and the excess volume expansivity is evaluated. The negative values of excess molar volume for the mixture indicate the ion-dipole interactions and packing between IL and PEG oligomer. The results of binary excess property (VmE and deviations (Δη, ∆xn, ∆Фn, ∆xR, and ∆ФR are discussed in terms of molecular interactions and molecular structures in the binary mixture.

  8. Processes assessment in binary mixture plant

    Directory of Open Access Journals (Sweden)

    N. Shankar Ganesh, T. Srinivas

    2013-01-01

    Full Text Available Binary fluid system has an efficient system of heat recovery compared to a single fluid system due to a better temperature match between hot and cold fluids. There are many applications with binary fluid system i.e. Kalina power generation, vapor absorption refrigeration, combined power and cooling etc. Due to involvement of three properties (pressure, temperature and concentration in the processes evaluation, the solution is complicated compared to a pure substance. The current work simplifies this complex nature of solution and analyzes the basic processes to understand the processes behavior in power generation as well as cooling plants. Kalina power plant consists of regenerator, heat recovery vapor generator, condenser, mixture, separator, turbine, pump and throttling device. In addition to some of these components, the cooling plant consists of absorber which is similar in operation of condenser. The amount of vapor at the separator decreases with an increase in its pressure and temperature.

  9. 含离子液体溴化1-丙基-3-甲基咪唑的二元和三元体系的蒸气压测定%Determination of Vapor Pressures for Binary and Ternary Mixtures Containing Ionic Liquid 1-propyl-3-methylimidazolium Bromide

    Institute of Scientific and Technical Information of China (English)

    Zakariya R.Abusen; 赵瑾; 李春喜; 王子镐

    2005-01-01

    Vapor pressure values of binary systems water + ethanol, water + ionic liquid 1-propyl-3-methylimidazolium bromide ([PMIM] [Br]), ethanol + [PMIM][Br] and ternary system water + ethanol + [PMIM] [Br]at different temperatures were measured by using a modified boiling point method in various concentrations of (16.66%, 33.7%), (17.4%, 33.9%) and (16.5%, 32%) mass percent of ionic liquid, respectively. The experimental vapor pressures of solvent were well correlated by the Antoine-type equation, and the overall average absolute deviation (AAD) was found to be 0.39%. The experimental results for mixtures containing ionic liquid indicate that the vapor pressure of the solvents can be decreased noticeably to different extent due to the affinity difference between ionic liquid and solvent, which is similar to the salt effect of common inorganic salts. As a result, ionic liquid may find industrial applications in extractive distillations for the system with a low separation factor or even for an azeotropic mixture.

  10. Phase Behavior of Mixtures of Ionic Liquids and Organic Solvents

    DEFF Research Database (Denmark)

    Abildskov, Jens; Ellegaard, Martin Dela; O’Connell, J.P.

    2010-01-01

    A corresponding-states form of the generalized van der Waals equation, previously developed for mixtures of an ionic liquid and a supercritical solute, is here extended to mixtures including an ionic liquid and a solvent (water or organic). Group contributions to characteristic parameters...... solvents. Here we show results for heavier and more-than-sparingly solutes such as carbon dioxide and propane in ionic liquids....

  11. Density and molar volumes of imidazolium-based ionic liquid mixtures and prediction by the Jouyban-Acree model

    Science.gov (United States)

    Ghani, Noraini Abd; Sairi, Nor Asrina; Mat, Ahmad Nazeer Che; Khoubnasabjafari, Mehry; Jouyban, Abolghasem

    2016-11-01

    The density of imidazolium-based ionic liquid, 1-ethyl-3-methylimidazolium diethylphosphate with sulfolane were measured at atmospheric pressure. The experiments were performed at T= (293 - 343) K over the complete mole fractions. Physical and thermodynamic properties such as molar volumes, V0, and excess molar volumes, VE for this binary mixtures were derived from the experimental density data. The Jouyban-Acree model was exploited to correlate the physicochemical properties (PCPs) of binary mixtures at various mole fractions and temperatures.

  12. Playing with ionic liquid mixtures to design engineered CO2 separation membranes.

    Science.gov (United States)

    Tomé, Liliana C; Florindo, Catarina; Freire, Carmen S R; Rebelo, Luís Paulo N; Marrucho, Isabel M

    2014-08-28

    Ionic liquids have been explored as attractive alternative media for CO2 separation not only due to their low volatility but also due to their highly tuneable nature. Aiming at designing highly efficient liquid phases for flue gas separation and natural gas purification, this work focuses on the use of binary ionic liquid mixtures containing sulfate and/or cyano-functionalized anions. Several mixtures were prepared and their gas transport properties through supported ionic liquid membranes (SILMs) were investigated. The thermophysical properties of these mixtures, namely viscosity and density (data presented and discussed in ESI), were also measured so that trends between transport properties and thermophysical properties could be evaluated. The results obtained indicate that depending on the anions mixed, membranes with fine-tuned gas permeabilities, diffusivities and solubilities can be obtained. Additionally, SILMs prepared with these ionic liquid mixtures are on the upper bound of the CO2/N2 separation, or even may surpass it, indicating their potential for separating CO2 in low-pressure post-combustion processes. Overall, the use of ionic liquid mixtures combining the most selective anions with the least viscous anions is a highly promising strategy to design advanced engineered liquid phases for CO2 separation membranes.

  13. Importance of Molecular Structure on the Thermophoresis of Binary Mixtures.

    Science.gov (United States)

    Kumar, Pardeep; Goswami, Debabrata

    2014-12-26

    Using thermal lens spectroscopy, we study the role of molecular structural isomers of butanol on the thermophoresis (or Soret effect) of binary mixtures of methanol in butanol. In this study, we show that the thermal lens signal due to the Soret effect changes its sign for all the different concentrations of binary mixtures of butanol with methanol except for the one containing tertiary-butanol. The magnitude and sign of the Soret coefficients strongly depend on the molecular structure of the isomers of butanol in the binary mixture with methanol. This isomerization dependence is in stark contrast to the expected mass dependence of the Soret effect.

  14. Mutual and thermal diffusivity of binary mixtures of the ionic liquids [BMIM][C(CN)3] and [BMIM][B(CN)4] with dissolved CO2 by dynamic light scattering.

    Science.gov (United States)

    Rausch, Michael H; Heller, Andreas; Herbst, Jonas; Koller, Thomas M; Bahlmann, Matthias; Schulz, Peter S; Wasserscheid, Peter; Fröba, Andreas P

    2014-05-01

    Ionic liquids (ILs) are promising solvents for gas separation processes such as carbon dioxide (CO2) capture from flue gases. For the design of corresponding processes and apparatus, thermophysical properties of ILs containing dissolved gases are required. In the present study, it is demonstrated that with a single optical setup, mutual and thermal diffusivities as well as refractive indices can be measured quasi-simultaneously for such mixtures. Dynamic light scattering (DLS) from bulk fluids was applied to determine mutual and thermal diffusivities for mixtures of 1-butyl-3-methylimidazolium tricyanomethanide ([BMIM][C(CN)3]) or 1-butyl-3-methylimidazolium tetracyanoborate ([BMIM][B(CN)4]) with dissolved CO2 at temperatures from 303.15 to 333.15 K and pressures between 2 and 26 bar in macroscopic thermodynamic equilibrium. Good agreement with literature data and only slight differences between the diffusivities measured for the two systems at the same temperature and comparable mole fractions of CO2 were found. Increasing mutual diffusivities with increasing mole fractions of CO2 are consistent with decreasing viscosities reported for other IL-CO2 mixtures in the literature and can be attributed to weakening of molecular interactions by the dissolved gas. For the conditions studied, no dependence of the thermal diffusivity on the temperature or the mole fraction of CO2 could be found.

  15. Ecotoxicological characterization of polyoxyethylene glycerol ester non-ionic surfactants and their mixtures with anionic and non-ionic surfactants.

    Science.gov (United States)

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Fernández-Serrano, Mercedes

    2017-03-03

    This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria (Vibrio fischeri), microalgae (Pseudokirchneriella subcapitata), and freshwater crustaceans (Daphnia magna). Relationships between toxicity and the structural parameters such as unit of ethylene oxide (EO) and hydrophilic-lipophilic balance (HLB) were evaluated. Critical micellar concentration (CMC) in the conditions of the toxicity test was also determined. It was found that the toxicity of the aqueous solutions of PGE decreased when the number of EO units in the molecule, HLB, and CMC increased. PGEs showed lower CMC in marine medium, and the toxicity to V. ficheri is lower when the CMC was higher. Given their non-polar nature, narcosis was expected to be the primary mode of toxic action of PGEs. For the mixture of surfactants, we observed that the mixtures with PGE that had the higher numbers of EO units were more toxic than the aqueous solutions of pure surfactants. Moreover, we found that concentration addition was the type of action more likely to occur for mixtures of PGE with lower numbers of EO units with non-ionic surfactants (alkylpolyglucoside and fatty alcohol ethoxylate), whereas for the mixture of PGE with lower EO units and anionic surfactant (ether carboxylic derivative), the most common response type was response addition. In case of mixtures involving amphoteric surfactants and PGEs with the higher numbers of EO units, no clear pattern with regard to the mixture toxicity response type could be observed.

  16. New Method for the Estimation of Viscosity of Pure and Mixtures of Ionic Liquids Based on the UNIFAC–VISCO Model

    OpenAIRE

    Zhao, Nan; Jacquemin, Johan; Oozeerally, Ryan; Degirmenci, Volkan

    2016-01-01

    A modified UNIFAC–VISCO group contribution method was developed for the correlation and prediction of viscosity of ionic liquids as a function of temperature at 0.1 MPa. In this original approach, cations and anions were regarded as peculiar molecular groups. The significance of this approach comes from the ability to calculate the viscosity of mixtures of ionic liquids as well as pure ionic liquids. Binary interaction parameters for selected cations and anions were determined by fitting the ...

  17. Determining the Porosity and Saturated Hydraulic Conductivity of Binary Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.; Ward, Anderson L.; Keller, Jason M.

    2009-09-27

    Gravels and coarse sands make up significant portions of some environmentally important sediments, while the hydraulic properties of the sediments are typically obtained in the laboratory using only the fine fraction (e.g., <2 mm or 4.75 mm). Researchers have found that the content of gravel has significant impacts on the hydraulic properties of the bulk soils. Laboratory experiments were conducted to measure the porosity and the saturated hydraulic conductivity of binary mixtures with different fractions of coarse and fine components. We proposed a mixing-coefficient model to estimate the porosity and a power-averaging method to determine the effective particle diameter and further to predict the saturated hydraulic conductivity of binary mixtures. The proposed methods could well estimate the porosity and saturated hydraulic conductivity of the binary mixtures for the full range of gravel contents and was successfully applied to two data sets in the literature.

  18. Phase diagrams of binary mixtures of oppositely charged colloids.

    Science.gov (United States)

    Bier, Markus; van Roij, René; Dijkstra, Marjolein

    2010-09-28

    Phase diagrams of binary mixtures of oppositely charged colloids are calculated theoretically. The proposed mean-field-like formalism interpolates between the limits of a hard-sphere system at high temperatures and the colloidal crystals which minimize Madelung-like energy sums at low temperatures. Comparison with computer simulations of an equimolar mixture of oppositely charged, equally sized spheres indicate semiquantitative accuracy of the proposed formalism. We calculate global phase diagrams of binary mixtures of equally sized spheres with opposite charges and equal charge magnitude in terms of temperature, pressure, and composition. The influence of the screening of the Coulomb interaction upon the topology of the phase diagram is discussed. Insight into the topology of the global phase diagram as a function of the system parameters leads to predictions on the preparation conditions for specific binary colloidal crystals.

  19. Dielectric studies of binary mixtures of -propyl alcohol and ethylenediamine

    Indian Academy of Sciences (India)

    B S Narwade; P G Gawali; Rekha Pande; G M Kalamse

    2005-11-01

    Dielectric constant (') and dielectric loss (") of -propyl alcohol (PA), ethylenediamine (EDA) and their binary mixtures, for different mole fractions of ethylenediamine have been experimentally measured at 11.15 GHz microwave frequency. Values of density (), viscosity () and square refractive index ($n^{2}_{D}$) of binary mixtures as well as those of pure liquids are reported. Excess square refractive index, viscosity and activation energy of viscous flow have also been estimated. These parameters have been used to explain the formation of complexes in the system.

  20. Intermolecular forces in acetonitrile + ethanol binary liquid mixtures

    Science.gov (United States)

    Elangovan, A.; Shanmugam, R.; Arivazhagan, G.; Mahendraprabu, A.; Karthick, N. K.

    2015-10-01

    FTIR spectral measurements have been carried out on the binary mixtures of acetonitrile with ethanol at 1:0 (acetonitrile:ethanol), 1:1, 1:2, 1:3 and 0:1 at room temperature. DFT and isosurface calculations have been performed. The acetonitrile + ethanol binary mixtures consist of 1:1, 1:2, 1:3 and 1:4 complexes formed through both the red and blue shifting H-bonds. Inter as well as intra molecular forces are found to exist in 1:3 and 1:4 complexes.

  1. Hydrogen component fugacities in binary mixtures with methane and propane

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, T.J.; Ely, J.F.; Hume, G.L.

    1986-09-01

    The fugacity coefficients of hydrogen in binary mixtures with methane and propane were measured using a physical equilibrium technique. This technique involves the use of an experimental chamber which is divided into two regions by a semipermeable membrane. Hydrogen can penetrate and pass through the membrane, while the other component (in this case, methane or propane) cannot. At equilibrium, pure hydrogen will permeate into one ''compartment'' of the chamber, while the binary mixture occupies the other compartment. Thus, the pressure of pure hydrogen on one side approaches the partial pressure of hydrogen in the mixture on the other side of the membrane. This allows a direct measurement of the hydrogen component fugacity at a given mixture mole fraction. In this study, results are reported for measurements made on the hydrogen+propane binary at 80 degrees C (353 K) and 130 degrees C (403 K) and the hydrogen+methane binary at 80 degrees C (353 K). All measurements were performed with a total mixture pressure of 3.45 MPa. The experimental results are compared with predictions from the Redlich-Kwong, Peng-Robinson, and extended corresponding-states models.

  2. Isomorphic Viscosity Equation of State for Binary Fluid Mixtures.

    Science.gov (United States)

    Behnejad, Hassan; Cheshmpak, Hashem; Jamali, Asma

    2015-01-01

    The thermodynamic behavior of the simple binary mixtures in the vicinity of critical line has a universal character and can be mapped from pure components using the isomorphism hypothesis. Consequently, based upon the principle of isomorphism, critical phenomena and similarity between P-ρ-T and T-η-(viscosity)-P relationships, the viscosity model has been developed adopting two cubic, Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR), equations of state (EsoS) for predicting the viscosity of the binary mixtures. This procedure has been applied to the methane-butane mixture and predicted its viscosity data. Reasonable agreement with the experimental data has been observed. In conclusion, we have shown that the isomorphism principle in conjunction with the mapped viscosity EoS suggests a reliable model for calculating the viscosity of mixture of hydrocarbons over a wide pressure range up to 35 MPa within the stated experimental errors.

  3. Ordered Structures of a Binary Mixture with Mobile Particles System

    Institute of Scientific and Technical Information of China (English)

    诸跃进; 马余强

    2003-01-01

    We study the ordered structures of a binary mixture through the introduction of mobile particles under periodically oscillating driving fields, and find that the particle motion can break up the isotropy of the system, so that the continuous structure along the oscillation forcing direction is observed for properly chosen oscillating field.Furthermore, the dependences of the morphology and domain size on the mixture-particle coupling interaction,the diffusion coefficient, and the quench depth are examined in details.

  4. Equation of state modeling of the phase equilibria of ionic liquid mixtures at low and high pressure.

    Science.gov (United States)

    Karakatsani, Eirini K; Economou, Ioannis G; Kroon, Maaike C; Bermejo, Maria D; Peters, Cor J; Witkamp, Geert-Jan

    2008-10-28

    Accurate design of processes based on ionic liquids (ILs) requires knowledge of the phase behavior of the systems involved. In this work, the truncated perturbed chain polar statistical associating fluid theory (tPC-PSAFT) is used to correlate the phase behavior of binary and ternary IL mixtures. Both non-polar and polar solvents are examined, while methyl imidazolium ILs are used in all cases. tPC-PSAFT accounts explicitly for weak dispersion interactions, highly directive polar interactions between permanent dipolar and quadrupolar molecules and association between hydrogen bonding molecules. For mixtures of non-polar solvents, tPC-PSAFT predicts accurately the binary mixture data. For the case of polar solvents, a binary interaction parameter is fitted to the experimental data and the agreement between experiment and correlation is very good in all cases.

  5. Ionic liquids for separation of olefin-paraffin mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng; Luo, Huimin; Huang, Jing-Fang

    2014-07-15

    The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula ##STR00001## wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group --N--SO.sub.2--(CF.sub.2).sub.nCF.sub.3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

  6. Steady-state organization of binary mixtures by active impurities

    DEFF Research Database (Denmark)

    Sabra, Mads Christian; Gilhøj, Henriette; Mouritsen, Ole G.

    1998-01-01

    The structural reorganization of a phase-separated binary mixture in the presence of an annealed dilution of active impurities is studied by computer-simulation techniques via a simple two-dimensional lattice-gas model. The impurities, each of which has two internal states with different affinity...

  7. Onsager coefficients for binary mixture diffusion in nanopores

    NARCIS (Netherlands)

    Krishna, R.; van Baten, J.M.

    2008-01-01

    This paper presents a critical appraisal of current estimation methods for the Onsager coefficients L-11, L-22, and L-12 for binary mixture diffusion inside nanopores using pure component diffusivity data inputs. The appraisal is based on extensive sets of molecular dynamics (MD) simulation data on

  8. Composition measurements of binary mixture droplets by rainbow refractometry.

    Science.gov (United States)

    Wilms, J; Weigand, B

    2007-04-10

    So far, refractive index measurements by rainbow refractometry have been used to determine the temperature of single droplets and ensembles of droplets. Rainbow refractometry is, for the first time, to the best of our knowledge, applied to measure composition histories of evaporating, binary mixture droplets. An evaluation method is presented that makes use of Airy theory and the simultaneous size measurement by Mie scattering imaging. The method further includes an empirical correction function for a certain diameter and refractive index range. The measurement uncertainty was investigated by numerical simulations with Lorenz-Mie theory. For the experiments, an optical levitation setup was used allowing for long measurement periods. Temperature measurements of single-component droplets at different temperature levels are shown to demonstrate the accuracy of rainbow refractometry. Measurements of size and composition histories of binary mixture droplets are presented for two different mixtures. Experimental results show good agreement with numerical results using a rapid-mixing model.

  9. Analytical processing of binary mixture information by olfactory bulb glomeruli.

    Directory of Open Access Journals (Sweden)

    Max L Fletcher

    Full Text Available Odors are rarely composed of a single compound, but rather contain a large and complex variety of chemical components. Often, these mixtures are perceived as having unique qualities that can be quite different than the combination of their components. In many cases, a majority of the components of a mixture cannot be individually identified. This synthetic processing of odor information suggests that individual component representations of the mixture must interact somewhere along the olfactory pathway. The anatomical nature of sensory neuron input into segregated glomeruli with the bulb suggests that initial input of odor information into the bulb is analytic. However, a large network of interneurons within the olfactory bulb could allow for mixture interactions via mechanisms such as lateral inhibition. Currently in mammals, it is unclear if postsynaptic mitral/tufted cell glomerular mixture responses reflect the analytical mixture input, or provide the initial basis for synthetic processing with the olfactory system. To address this, olfactory bulb glomerular binary mixture representations were compared to representations of each component using transgenic mice expressing the calcium indicator G-CaMP2 in olfactory bulb mitral/tufted cells. Overall, dorsal surface mixture representations showed little mixture interaction and often appeared as a simple combination of the component representations. Based on this, it is concluded that dorsal surface glomerular mixture representations remain largely analytical with nearly all component information preserved.

  10. Thermodiffusion of polycyclic aromatic hydrocarbons in binary mixtures

    Science.gov (United States)

    Hashmi, Sara M.; Senthilnathan, Sid; Firoozabadi, Abbas

    2016-11-01

    Thermodiffusion in liquid mixtures may explain some counter-intuitive but naturally occurring phenomena such as hydrocarbon reservoirs with heavier component(s) stratified on top of lighter ones. However, beyond benchmark systems, systematic measurements of thermodiffusion in binary organic mixtures are lacking. We use an optical beam deflection apparatus to simultaneously probe Fickian and thermal diffusion in binary solution mixtures of polycyclic aromatic hydrocarbons dissolved in alkanes, and measure both Fickian diffusion D and the Soret coefficient ST, and then obtain the thermodiffusion coefficient DT. In a series of nine binary mixtures, we vary both the size of the aromatic compound from two to four rings, as well as the length of the alkane chain from 6 to 16 carbons. To probe the effect of increasing ring size, we include a 6-ringed aromatic compound, coronene, and toluene as a solvent, due to the insolubility of coronene in alkanes. Our results suggest that Fickian diffusion increases with the inverse of solvent viscosity and also with decreasing molecular weight of the solute. While both of these trends match our intuition, the behavior of ST and DT is more complicated. We find that ST and DT increase with the solute molecular weight when the solvent is held fixed and that the impact of solute ring size is higher in shorter chain alkane solvents.

  11. DSMC simulation of Rayleigh-Brillouin scattering in binary mixtures

    Science.gov (United States)

    Bruno, Domenico; Frezzotti, Aldo; Ghiroldi, Gian Pietro

    2016-11-01

    Rayleigh-Brillouin scattering spectra (RBS) in dilute gas mixtures have been simulated by the Direct Simulation Monte Carlo method (DSMC). Different noble gas binary mixtures have been considered and the spectra have been simulated adopting the hard sphere collision model. It is suggested that DSMC simulations can be used in the interpretation of light scattering experiments in place of approximate kinetic models. Actually, the former have a firmer physical ground and can be readily extended to treat gas mixtures of arbitrary complexity. The results obtained confirm the capability of DSMC to predict experimental spectra and clears the way towards the simulation of polyatomic gas mixtures of interest for actual application (notably, air) where tractable kinetic model equations are still lacking.

  12. Modeling adsorption of binary and ternary mixtures on microporous media

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Shapiro, Alexander

    2007-01-01

    The goal of this work is to analyze the adsorption of binary and ternary mixtures on the basis of the multicomponent potential theory of adsorption (MPTA). In the MPTA, the adsorbate is considered as a segregated mixture in the external potential field emitted by the solid adsorbent. This makes...... it possible using the same equation of state to describe the thermodynamic properties of the segregated and the bulk phases. For comparison, we also used the ideal adsorbed solution theory (IAST) to describe adsorption equilibria. The main advantage of these two models is their capabilities to predict...

  13. Effects of lubricants on binary direct compression mixtures.

    Science.gov (United States)

    Uğurlu, T; Halaçoğlu, M D; Türkoğlu, M

    2010-04-01

    The objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant on binary direct compression mixtures. Magnesium stearate (MGST), stearic acid (STAC), glyceryl behenate (COMP) and hexagonal boron nitride (HBN) were tested. The binary mixtures were 1:1 combinations of spray dried lactose (FlowLac 100), dicalcium phosphate dihydrate (Emcompress), and modified starch (Starch 1500) with microcrystalline cellulose (Avicel PH 102). Tablets were manufactured on a single-station instrumented tablet press with and without lubricants. In the case of unlubricated granules, the modified starch-microcrystalline cellulose mixture provided the highest percent compressibility value at 8.25%, spray dried lactose-microcrystalline cellulose mixture was 7.33%, and the dialcium phosphate dihydrate-microcrystalline cellulose mixture was 5.79%. Their corresponding tablet crushing strength values were: 104 N, 117 N, and 61 N, respectively. The lubricant concentrations studied were 0.5, 1, 2, and 4%. Effects of lubricant type and lubricant concentration on crushing strength were analyzed using a factorial ANOVA model. It was found that the Avicel PH 102-Starch 1500 mixture showed the highest lubricant sensitivity (110 N vs. 9 N), the least affected formulation was FlowLac-Avicel PH 102 mixture (118 N vs. 62 N). The crushing strength vs. concentration curve for MGST showed a typical biphasic profile, a fast drop up to 1% and a slower decline between 1 and 4%. The STAC, COMP, and HBN for all formulations showed a shallow linear decline of tablet crushing strength with increasing lubricant concentration. The HBN was as effective as MGST as a lubricant, and did not show a significant negative effect on the crushing strength of the tablets. The COMP and STAC also did not interfere with the crushing strength, however, they were not as effective lubricants as MGST or HBN.

  14. Prediction of film boiling heat transfer coefficients for binary mixtures

    Science.gov (United States)

    Liu, Ming-Huei; Yang, Yu-Min; Maa, Jer-Ru

    Film boiling of binary liquid mixtures may be significantly different from that of single-component liquids due to the mass diffusion effect. A theoretical analysis is performed to outline the effects of mass diffusion phenomena on film boiling heat transfer process from a horizontal cylinder heating surface to the binary liquid mixtures of ethylene oxide/water and ethanol/benzene over whole range of compositions. These two binary systems are chosen for illustrating the strong and weak mass diffusion effects, respectively, on film boiling. Furthermore, a simple correlation for predicting heat transfer coefficient is proposed to demonstrate the idea that the dimensionless F factor can satisfactorily account for the mass diffusion effect on film boiling heat transfer of binary mixtures. Zusammenfassung Infolge des Stoffdiffusionseffektes kann sich das Filmsiedeverhalten binärer Flüssigkeitsgemische ganz wesentlich von dem der Einzelkomponentenfluide unterscheiden. In einer theoretischen Studie sollen die Einflüsse der Stoffdiffusionsphänomene auf den Wärmeübergang beim Filmsieden untersucht werden, und zwar bezüglich einer horizontalen zylindrischen Heizfläche, die Wärme an die Binärgemische Ethylenoxid/Wasser und Ethanol/Benzol bei beliebigen Konzentrationsverhältnissen abgibt. Die beiden Binärsysteme wurden ausgewählt, um einmal starken und dann schwachen Einfluß des Stoffdiffusionseffektes auf das Filmsieden zu zeigen. Schließlich wird eine einfache Korrelationsbeziehung zur Berechnung von Wärmeübergangskoeffizienten vorgeschlagen, die darlegen soll, daß der dimensionslose F-Faktor geeignet ist, den Einfluß des Stoffdiffusionseffektes auf das Filmsieden binärer Gemische befriedigend zu berücksichtigen.

  15. Surface tension at the liquid-vapor interface of screened ionic mixtures

    Directory of Open Access Journals (Sweden)

    M.González-Melchor

    2004-01-01

    Full Text Available The liquid-vapor interface of binary mixtures of charged particles is studied using molecular dynamics (MD simulations. The interaction between particles is given by a short-range repulsive potential plus an attractive/repulsive Yukawa term, which models screened electrostatic interactions. To obtain the components of the pressure tensor two methods were used: a hybrid MD method which combines the hard sphere and continuous forces and a standard continuous MD method where the hard sphere was replaced by a soft interaction. We show that both models give essentially the same results. As the range of interaction decreases, the critical temperature and surface tension increase. The comparison with the restricted primitive model of ionic fluids is discussed.

  16. Diffusion measurements in binary liquid mixtures by Raman spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Hansen, Susanne Brunsgaard; Shapiro, Alexander

    2007-01-01

    It is shown that Raman spectroscopy allows determination of the molar fractions in mixtures subjected to molecular diffusion. Spectra of three binary systems, benzene/n-hexane, benzene/cyclohexane, and benzene/ acetone, were obtained during vertical (exchange) diffusion at several different heights...... in the literature were found, even in a thermostatically controlled diffusion cell, recording spectra through circulating water. For the system benzene/acetone, the determined diffusion coefficients were in good agreement with the literature data. The limitations of the Raman method are discussed...

  17. Rayleigh-Brillouin Scattering in Binary Gas Mixtures

    CERN Document Server

    Gu, Ziyu; van de Water, Willem; Marques, Wilson

    2015-01-01

    Precise measurements are performed on spectral lineshapes of spontaneous Rayleigh-Brillouin scattering in mixtures of the noble gases Ar and Kr, with He. Admixture of a light He atomic fraction results in marked changes of the spectra, although in all experiments He is merely a spectator atom: it affects the relaxation of density fluctuations of the heavy constituent, but its contribution to the scattered light intensity is negligibly small. The results are compared to a theory for the spectral lineshape without adjustable parameters, yielding excellent agreement for the case of binary mono-atomic gases, signifying a step towards modeling and understanding of light scattering in more complex molecular media.

  18. The Hamilton principle for fluid binary mixtures with two temperatures

    CERN Document Server

    Gouin, Henri

    2009-01-01

    For binary mixtures of fluids without chemical reactions, but with components having different temperatures, the Hamilton principle of least action is able to produce the equation of motion for each component and a balance equation of the total heat exchange between components. In this nonconservative case, a Gibbs dynamical identity connecting the equations of momenta, masses, energy and heat exchange allows to deduce the balance equation of energy of the mixture. Due to the unknown exchange of heat between components, the number of obtained equations is less than the number of field variables. The second law of thermodynamics constrains the possible expression of a supplementary constitutive equation closing the system of equations. The exchange of energy between components produces an increasing rate of entropy and creates a dynamical pressure term associated with the difference of temperature between components. This new dynamical pressure term fits with the results obtained by classical thermodynamical a...

  19. The Amphiphilic Character of Cellulose Molecules in True Solution in Solvent Mixtures Containing Ionic Liquid and its Utilization in Emulsification

    Science.gov (United States)

    Napso, Sofia; Cohen, Yachin; Rein, Dmitry; Khalfin, Rafail; Szekely, Noemi

    2015-03-01

    Cellulose is the most abundant renewable material in nature that is utilized as a raw material for fabrication of synthetic products. Although it is not soluble in common solvents, there is significant interest in the use of solvent mixtures containing ionic liquids (IL) and polar organic solvents for cellulose dissolution. We present evidence for true molecular dissolution of cellulose in binary mixtures of common polar organic solvents with an ionic liquid, using cryogenic transmission electron microscopy, small-angle neutron-, x-ray- and static light scattering. In particular, the measured low values of the molecular, gyration radius and persistence length indicate the absence of significant aggregation of the dissolved chains. We conjecture that the dissolved cellulose chains are amphiphilic. This can be inferred from the facile fabrication of cellulose-encapsulated colloidal oil-in-water or water-in-oil dispersions. This may be done by mixing water, oil and cellulose solution in an ionic liquid. A more practical alternative is to form first a hydrogel from the cellulose/ionic liquid solution by coagulation with water and applying it to sonicated water/oil or oil/water mixtures. Apparently the dissolution/ regeneration process affords higher mobility to the cellulose molecules so an encapsulation coating can be formed at the water-oil interface.

  20. Phase equilibria study of the binary systems (N-hexylisoquinolinium thiocyanate ionic liquid + organic solvent or water).

    Science.gov (United States)

    Królikowska, Marta; Karpińska, Monika; Zawadzki, Maciej

    2012-04-12

    Liquid-liquid phase equilibria (LLE) of binary mixtures containing a room-temperature ionic liquid N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] with an aliphatic hydrocarbon (n-hexane, n-heptane), aromatic hydrocarbon (benzene, toluene, ethylbenzene, n-propylbenzene), cyclohexane, thiophene, water, and 1-alcohol (1-ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol) have been determined using a dynamic method from room temperature to the boiling-point of the solvent at ambient pressure. N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] has been synthesized from N-hexyl-isoquinolinium bromide as a substrate. Specific basic characterization of the new compound including NMR spectra, elementary analysis, and water content have been done. The density and viscosity of pure ionic liquid were determined over a wide temperature range from 298.15 to 348.15 K. The mutual immiscibility with an upper critical solution temperature (UCST) for the binary systems {IL + aliphatic hydrocarbon, cyclohexane, or water} was detected. In the systems of {IL + aromatic hydrocarbon or thiophene} an immiscibility gap with a lower critical solution temperature (LCST) was observed. Complete miscibility in the liquid phase, over a whole range of ionic liquid mole fraction, was observed for the binary mixtures containing IL and an 1-alcohol. For the tested binary systems with immiscibility gap {IL + aliphatic hydrocarbon, aromatic hydrocarbon, cyclohexane, thiophene, or water}, the parameters of the LLE correlation have been derived using the NRTL equation. The basic thermal properties of the pure IL, that is, the glass-transition temperature as well as the heat capacity at the glass-transition temperature, have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the IL was detected by simultaneous thermogravimetric/differential thermal analysis (TG/DTA) experiments.

  1. Positronium in solid phases of n-alkane binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Zgardzińska, B.; Goworek, T.

    2015-09-08

    Highlights: • Rotator phase in even alkanes C{sub n}H{sub 2n+2} with n ⩽ 20 appears in mixed samples only. • Interlamellar gap width is the same for shorter chain alkane concentration x and 1 − x. • Excess electron trapping diminishes with broadening of alkane chain distribution Δn. - Abstract: Binary mixtures of even-numbered normal alkanes C{sub n}H{sub 2n+2} and C{sub n+2}H{sub 2n+6} with n ⩽ 18 were investigated by positron annihilation spectroscopy. Formation of the rotator phase was observed in mixed structures, while no such a phase in neat alkanes in this range of n was found. Phase diagrams for n = 18 and n = 16 are very similar to the diagrams for binary mixtures of odd-numbered alkanes. The effect of positronium formation with trapped excess electrons weakens with decreasing n, at low n values the time constant of Ps rise contains the component much shorter than 1 h.

  2. 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...

  3. Analysis of composition complicated binary mixture by quantitative SEC

    Institute of Scientific and Technical Information of China (English)

    Zhengnian CHEN; Hongfeng XIE; Hu YANG; Zhiliu WANG; Rongshi CHENG

    2008-01-01

    The analyses of the composition of a binary mixture composed of two kinds of industrial complicated materials have great importance for formulation in practice.The present paper provides a quantitative size exclusion chromatography (SEC) method based on the principle of absolute quantification of SEC to solve the problem. The conventional data treatment procedure for the differential refractive index (DRI) signal of SEC H(V) is improved first by dividing it with the injected sample weight and leads to a novel defined weight normalized distribution Hw(V) and its integral Iw(V). These two distributions reflect the response constant of the sample in addition to the conventional normalized distribution F(V). The difference of the average response constants of the composing components provides a sensitive method to compute the composition of their mixture from its Hw(V) or Iw(V). The method was applied to mixtures of a kind of industrial asphalt and paraffin diluents as an example, and successful results are obtained.

  4. New insight into phase equilibria involving imidazolium bistriflamide ionic liquids and their mixtures with alcohols and water.

    Science.gov (United States)

    Pereiro, Ana B; Deive, Francisco J; Rodríguez, Ana; Ruivo, Diana; Canongia Lopes, José N; Esperança, José M S S; Rebelo, Luís P N

    2010-07-15

    The fluid phase equilibria (liquid-liquid demixing behavior (LLE)) of mixtures of ionic liquids of the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide family, [C(n)mim][NTf(2)], with 2-methylpropanol or n-octanol were investigated. Binary mixtures of [C(4)mim][NTf(2)] + alcohol and [C(6)mim][NTf(2)] + alcohol were compared to pseudobinary mixtures of (0.5[C(2)mim] + 0.5[C(6)mim])[NTf(2)] + alcohol and (0.5[C(2)mim] + 0.5[C(10)mim])[NTf(2)] + alcohol, respectively. Additionally, the presence of water in the studied alcohols or as a third component in the system was analyzed in order to check any possible deviation from the LLE observed for the anhydrous systems. Systems containing small fractions of ionic liquid show similar LLE between the corresponding binary and pseudobinary systems; however, large differences are observed in the presence of water when the IL mass fraction is increased.

  5. Stability studies of colloidal silica dispersions in binary solvent mixtures

    CERN Document Server

    Bean, K H

    1997-01-01

    A series of monodispersed colloidal silica dispersions, of varying radii, has been prepared. These particles are hydrophilic in nature due to the presence of surface silanol groups. Some of the particles have been rendered hydrophobic by terminally grafting n-alkyl (C sub 1 sub 8) chains to the surface. The stability of dispersions of these various particles has been studied in binary mixtures of liquids, namely (i) ethanol and cyclohexane, and (ii) benzene and n-heptane. The ethanol - cyclohexane systems have been studied using a variety of techniques. Adsorption excess isotherms have been established and electrophoretic mobility measurements have been made. The predicted stability of the dispersions from D.V.L.O. calculations is compared to the observed stability. The hydrophilic silica particles behave as predicted by the calculations, with the zeta potential decreasing and the van der Waals attraction increasing with increasing cyclohexane concentration. The hydrophobic particles behave differently than e...

  6. Evaporation of Ethanol-Water Binary Mixture Sessile Liquid Marbles.

    Science.gov (United States)

    Ooi, Chin Hong; Bormashenko, Edward; Nguyen, Anh V; Evans, Geoffrey M; Dao, Dzung V; Nguyen, Nam-Trung

    2016-06-21

    Liquid marble is a liquid droplet coated with particles. Recently, the evaporation process of a sessile liquid marble using geometric measurements has attracted great attention from the research community. However, the lack of gravimetric measurement limits further insights into the physical changes of a liquid marble during the evaporation process. Moreover, the evaporation process of a marble containing a liquid binary mixture has not been reported before. The present paper investigates the effective density and the effective surface tension of an evaporating liquid marble that contains aqueous ethanol at relatively low concentrations. The effective density of an evaporating liquid marble is determined from the concurrent measurement of instantaneous mass and volume. Density measurements combined with surface profile fitting provide the effective surface tension of the marble. We found that the density and surface tension of an evaporating marble are significantly affected by the particle coating.

  7. Particle segregation during explosive dispersal of binary particle mixtures

    Science.gov (United States)

    Frost, David L.; Loiseau, Jason; Marr, Bradley J.; Goroshin, Samuel

    2017-01-01

    The explosive dispersal of a layer of solid particles surrounding a spherical high explosive charge generates a turbulent, multiphase flow. The shock-compacted particle layer typically fractures into discrete fragments which move radially outwards on ballistic trajectories. The fragments shed particles in their wakes forming jet-like structures. The tendency to form jets depends on the mass-ratio of the particles to explosive and the type of particles. Brittle or soft, ductile particles are more susceptible to forming jets during compaction and dispersal, whereas particles that are comprised of material with moderate hardness, high compressive strength and high toughness are much less prone to forming jets. Experiments have been carried out to determine the degree of particle segregation that occurs during the explosive dispersal of a uniform, binary mixture containing both "jetting" (silicon carbide) and "non-jetting" (steel) particles with various mass fractions of each particle type. During the dispersal of mixtures that contain predominantly non-jetting (steel) particles, the steel particles form a stable layer whereas the jetting (silicon carbide) particles rapidly segregate and form jets which are confined within the shell of steel particles. As the fraction of silicon carbide particles increases, the jet structures dominate the particle motion and the steel particles are entrained into the jet structures.

  8. A Variational approach to thin film hydrodynamics of binary mixtures

    KAUST Repository

    Xu, Xinpeng

    2015-02-04

    In order to model the dynamics of thin films of mixtures, solutions, and suspensions, a thermodynamically consistent formulation is needed such that various coexisting dissipative processes with cross couplings can be correctly described in the presence of capillarity, wettability, and mixing effects. In the present work, we apply Onsager\\'s variational principle to the formulation of thin film hydrodynamics for binary fluid mixtures. We first derive the dynamic equations in two spatial dimensions, one along the substrate and the other normal to the substrate. Then, using long-wave asymptotics, we derive the thin film equations in one spatial dimension along the substrate. This enables us to establish the connection between the present variational approach and the gradient dynamics formulation for thin films. It is shown that for the mobility matrix in the gradient dynamics description, Onsager\\'s reciprocal symmetry is automatically preserved by the variational derivation. Furthermore, using local hydrodynamic variables, our variational approach is capable of introducing diffusive dissipation beyond the limit of dilute solute. Supplemented with a Flory-Huggins-type mixing free energy, our variational approach leads to a thin film model that treats solvent and solute in a symmetric manner. Our approach can be further generalized to include more complicated free energy and additional dissipative processes.

  9. Morphological transformations in polymer brushes in binary mixtures: DPD study.

    Science.gov (United States)

    Cheng, Jianli; Vishnyakov, Aleksey; Neimark, Alexander V

    2014-11-04

    Morphological transformations in polymer brushes in a binary mixture of good and bad solvents are studied using dissipative particle dynamics simulations drawing on a characteristic example of polyisoprene natural rubber in an acetone-benzene mixture. A coarse-grained DPD model of this system is built based on the experimental data in the literature. We focus on the transformation of dense, collapsed brush in bad solvent (acetone) to expanded brush solvated in good solvent (benzene) as the concentration of benzene increases. Compared to a sharp globule-to-coil transition observed in individual tethered chains, the collapsed-to-expanded transformation in brushes is found to be gradual without a prominent transition point. The transformation becomes more leveled as the brush density increases. At low densities, the collapsed brush is highly inhomogeneous and patterned into bunches composed of neighboring chains due to favorable polymer-polymer interaction. At high densities, the brush is expanded even in bad solvent due to steric restrictions. In addition, we considered a model system similar to the PINR-acetone-benzene system, but with the interactions between the solvent components worsened to the limit of miscibility. Enhanced contrast between good and bad solvents facilitates absorption of the good solvent by the brush, shifting the collapsed-to-expanded transformation to lower concentrations of good solvent. This effect is especially pronounced for higher brush densities.

  10. Evaporation dynamics and Marangoni number estimation for sessile picoliter liquid drop of binary mixture solution

    Directory of Open Access Journals (Sweden)

    Lebedev-Stepanov Peter

    2016-01-01

    Full Text Available We propose the evaporation model of picoliter sessile drop of binary solvent mixture (with infinitely soluble in each other components based on Hu and Larson solution for single solvent sessile drop and Raoult law for saturated vapor density of components of binary mixture in wide range of undimensional molar binary concentration of the components. Concentration Marangoni number estimation for such a system is also considered for prediction of liquid flows structure for further applications in dissipative particle dynamics in binary mixture evaporating drop.

  11. Unusual solvatochromic absorbance probe behaviour within mixtures of poly(ethylene glycol)-400 + ionic liquid, [bmim][Tf2N

    Science.gov (United States)

    Ali, Anwar; Ali, Maroof; Malik, Nisar Ahmad; Uzair, Sahar

    2014-03-01

    The potentially green solvents made up of ionic liquids (ILs) and poly(ethylene glycols) may have wide range of the applications in many chemical and biochemical fields. In the present work, solvatochromic absorbance probe behaviour is used to assess the physicochemical properties of the mixtures composed of PEG-400 + IL, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf2N]. Lowest energy intramolecular charge-transfer absorbance maxima of a betaine dye, i.e., ETN , indicates the dipolarity/polarizability and/or hydrogen-bond donating (HBD) acidity of the [bmim][Tf2N] + PEG-400 mixtures to be even higher than that of neat [bmim][Tf2N], the solution component with higher dipolarity/polarizability and/or HBD acidity. Dipolarity/polarizability (π∗) obtained separately from the electronic absorbance response of probe N,N-diethyl-4-nitroaniline, and the HBD acidity (α) of PEG-400 + [bmim][Tf2N] mixtures are also observed to be anomalously high. A comparative study of the PEG + IL mixtures has also been done with PEG-400 + molecular organic solvents (protic polar [methanol], aprotic polar [N,N-dimethylformamide], and non polar, [benzene]) mixtures, but these mixtures do not show this type of unusual behaviour. A four-parameter simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation is shown to satisfactorily predict the solvatochromic parameters within PEG-400 + different solvent mixtures.

  12. Fine tuning the ionic liquid-vacuum outer atomic surface using ion mixtures.

    Science.gov (United States)

    Villar-Garcia, Ignacio J; Fearn, Sarah; Ismail, Nur L; McIntosh, Alastair J S; Lovelock, Kevin R J

    2015-03-28

    Ionic liquid-vacuum outer atomic surfaces can be created that are remarkably different from the bulk composition. In this communication we demonstrate, using low-energy ion scattering (LEIS), that for ionic liquid mixtures the outer atomic surface shows significantly more atoms from anions with weaker cation-anion interactions (and vice versa).

  13. Heat Transfer in Nucleate Pool Boiling of Binary and Ternary Refrigerant Mixtures

    Institute of Scientific and Technical Information of China (English)

    赵耀华; 刁彦华; 鹤田隆治; 西川日出男

    2004-01-01

    Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients.

  14. Understanding the destructuration of starch in water-ionic liquid mixtures

    OpenAIRE

    2015-01-01

    The destructuration of native maize starch in mixtures of water and ionic liquids (ILs) containing acetate anions was studied in dynamic heating conditions, combining calorimetry, rheology, microscopy and chromatographic techniques. A phase diagram of starch in water-IL solutions was established. The phase transitions undergone by starch include the typical endothermic gelatinization phenomenon for IL-water ratios lower than 0.5, while for mixtures with a higher ionic liquid content, a comple...

  15. 离子液体[C4mim][PF6]与N,N-二甲基甲酰胺二元混合物在298.15 K~318.15 K的密度和粘度%Densities and Viscosities of the Ionic Liquid [C4mim][PF6]+N,N-dimethylformamide Binary Mixtures at 293.15 K to 318.15 K

    Institute of Scientific and Technical Information of China (English)

    耿彦芳; 王腾芳; 虞大红; 彭昌军; 刘洪来; 胡英

    2008-01-01

    Viscosities and densities for 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and N,N-dimethylformamide (DMF) binary mixtures have been measured at the temperature range from 293.15 K to 318.15 K. It is shown that the viscosities and densities decrease monotonously with temperature and the content of DME Various correlation methods including Arrhenius-like equation, Seddon et al.'s equation, Redlich-Kister equation with four parameters, and other empirical equations were applied to evaluate these experimental data. A model based on an equation of state for estimating the viscosity of mixtures containing ionic liquids were proposed by coupling with the excess Gibbs free energy model of viscosity, which can synchronously calculate the viscosity and the molar volume. The results show that the model gives a deviation of 8.29% for the viscosity, and a deviation of 1.05% for the molar volume when only one temperature-independent adjustable parameter is adopted. The cor-relation accuracy is further improved when two parameters or one temperature-dependent parameter is used.

  16. Biomass Pretreatment using Ionic Liquid and Glycerol Mixtures

    Science.gov (United States)

    Lynam, Joan Goerss

    Lignocellulosic biomass is a renewable, sustainable resource that can replace or supplement fossil fuels use for liquid fuels and chemicals. However, its recalcitrant structure including interwoven cellulose, hemicelluloses, and lignin biomacromolecules is challenging to deconstruct. Pretreating biomass so that it can be converted to useful liquids dominates process economics. Many pretreatment methods exist, but most require hazardous chemicals or processing conditions. Many ionic liquids (ILs), salts molten below 100°C, can be used to deconstruct lignocellulosic biomass and are less hazardous than the volatile organic compounds typically used. While effective, relatively safe, and recyclable, ILs are expensive. To reduce costs, dilution with other safe compounds is desirable, if there is no impact on deconstruction efficiency. Glycerol, a food additive, is inexpensive and becoming even more so since it is a by-product of the burgeoning biodiesel industry. Use of glycerol as an additive or diluent for ILs is extensively evaluated in this work. Rice hulls are an abundant biomass, with over 100 million tons produced per year, but with little practical use. The IL 1-ethyl-3-methylimidazolium formate ([C2mim][O2CH] or EMIM Form) when mixed with an equal amount of glycerol has been shown to be effective in pretreating rice hulls. Ambient pressure, a pretreatment temperature of 110°C, and a reaction time of three hours produced rice hulls that could be enzymatically hydrolyzed to give reasonably good glucose and xylose yields considering the recalcitrance of this silica-armored biomass. The IL [C2mim][O2CH] was also effective when mixed with an equal amount of glycerol to pretreat loblolly pine, a fast-growing softwood. Loblolly pine was pretreated at 140°C for three hours to produce a solid rich in cellulose and hemicelluloses, while a lignin-rich product could be precipitated from the IL. Similar products were obtained from pretreatment with a mixture of 75% 1

  17. Decomposition and interface evolution in films of binary mixtures

    Science.gov (United States)

    Madruga, Santiago; Bribesh, Fathi; Thiele, Uwe

    2011-11-01

    Model-H describes the coupled transport of concentration and momentum in binary mixtures such as polymer blends. Films of polymer blends are used in technological applications that involve coatings or the creation of structural functional layers. We use an extended version of the model-H for free evolving surfaces to analyze the stability of vertically stratified base states of polymer blends on a solid substrate. We determine the bifurcation diagram of the films by studying their free energy, and L2-norms of surface deflection and concentration field. We provide results for selected mean film thickness with and without energetic bias at the free surface and discuss the role of composition in extended and laterally bounded systems. In addition, we show that the inclusion of convective transport leads to new mechanisms of instability as compared to the purely diffusive case,. S.M. acknowledges support via FP7 Marie Curie Reintegration Grant (PERG04-GA-2008-234384), and U.T. by EU via FP7 (PITN-GA-2008-214919).

  18. Dissipation process of binary mixture gas in thermally relativistic flow

    CERN Document Server

    Yano, Ryosuke

    2016-01-01

    In this paper, we discuss dissipation process of the binary mixture gas in the thermally relativistic flow \\textcolor{red}{by focusing on the characteristics of the diffusion flux}. As an analytical object, we consider the relativistic rarefied-shock layer problem around the triangle prism. Numerical results of the diffusion flux are compared with the Navier-Stokes-Fourier (NSF) order approximation of the diffusion flux, which is calculated using the diffusion and thermal-diffusion coefficients by Kox \\textit{et al}. [Physica A, 84, 1, pp.165-174 (1976)]. In the case of the uniform flow with the small Lorentz contraction, the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is roughly approximated by the NSF order approximation inside the shock wave, whereas the diffusion flux in the vicinity of the wall is markedly different from the NSF order approximation. The magnitude of the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is simil...

  19. th-Nearest neighbour distribution functions of a binary fluid mixture

    Indian Academy of Sciences (India)

    P Sur; B Bhattacharjee

    2009-09-01

    For obtaining microscopic structural information in binary mixtures, often partial pair correlation functions are used. In the present study, a general approach is presented for obtaining the neighbourhood structural information for binary mixtures in terms of nth nearest neighbour distribution (NND) functions (for = 1, 2, 3, ...$\\ldots$). These functions are derived from the partial pair correlation functions in a hierarchical manner, based on the approach adopted earlier by us for single component fluids. Comparison of the results with MD simulation for Lennard-Jones binary mixtures is also presented. NND functions show reasonable matching for smaller n values particularly at higher density. The average th nearest neighbour distance shows interesting feature.

  20. Measurement and modeling of osmotic coefficients of binary mixtures (alcohol + 1,3-dimethylpyridinium methylsulfate) at T = 323.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Elena [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Calvar, Noelia, E-mail: noecs@uvigo.e [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Dominguez, Angeles [Advanced Separation Processes Group, Departamento de Ingenieria Quimica, Universidad de Vigo, 36310 Vigo (Spain); Macedo, Eugenia A. [Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)

    2011-06-15

    Research highlights: The osmotic coefficients of binary mixtures (alcohol + ionic liquid) were determined. The measurements were carried out with a vapor pressure osmometer at 323.15 K. The Pitzer-Archer, and the MNRTL models were used to correlate the experimental data. Mean molal activity coefficients and excess Gibbs free energies were calculated. - Abstract: Measurement of osmotic coefficients of binary mixtures containing several primary and secondary alcohols (1-propanol, 2-propanol, 1-butanol, 2-butanol, and 1-pentanol) and the pyridinium-based ionic liquid 1,3-dimethylpyridinium methylsulfate were performed at T = 323.15 K using the vapor pressure osmometry technique, and from experimental data, vapor pressure, and activity coefficients were determined. The extended Pitzer model modified by Archer, and the NRTL model modified by Jaretun and Aly (MNRTL) were used to correlate the experimental osmotic coefficients, obtaining standard deviations lower than 0.017 and 0.054, respectively. From the parameters obtained with the extended Pitzer model modified by Archer, the mean molal activity coefficients and the excess Gibbs free energy for the studied binary mixtures were calculated. The effect of the cation is studied comparing the experimental results with those obtained for the ionic liquid 1,3-dimethylimidazolium methylsulfate.

  1. Phase diagrams and solvate structures of binary mixtures of glymes and Na salts.

    Science.gov (United States)

    Mandai, Toshihiko; Nozawa, Risa; Tsuzuki, Seiji; Yoshida, Kazuki; Ueno, Kazuhide; Dokko, Kaoru; Watanabe, Masayoshi

    2013-12-05

    We prepared a series of binary mixtures composed of selected Na salts and glymes (tetraglyme, G4, and pentaglyme, G5) with different salt concentrations and anionic species ([X](-): [N(SO2CF3)2](-) = [TFSA](-), [N(SO2F)2](-) = [FSA](-), ClO4(-), PF6(-)) and studied the effects of concentration, anionic structure, and glyme chain length on their phase diagrams and solvate structures. The phase diagrams clearly illustrate that all the mixtures form 1:1 complexes, [Na(G4 or G5)1][X]. The thermal stability of the equimolar mixtures was drastically improved in comparison with those of diluted systems, indicating that all the glyme molecules coordinate to Na(+) cations to form equimolar complexes. Single-crystal X-ray crystallography revealed that [Na(G5)1][X] forms characteristic solvate structures in the crystalline state irrespective of the paired anion species. A comparison of the solvate structures of the glyme-Na complexes with those of the glyme-Li complexes suggests that the ionic radii of the coordinated alkali-metal cations have substantial effects on the resulting solvate structures. The Raman bands of the complex cations were assigned by quantum chemical calculations. Concentration dependencies of cationic and anionic Raman spectra show good agreement with the corresponding phase diagrams. In addition, the Raman spectra of the 1:1 complexes strongly suggest that the glymes coordinate to Na(+) cation in the same way in both liquid and crystalline states. However, the aggregated structure in the crystalline state is broken by melting, which is accompanied by a change in the anion coordination.

  2. Dissociation of equimolar mixtures of aqueous carboxylic acids in ionic liquids: role of specific interactions.

    Science.gov (United States)

    Shukla, Shashi Kant; Kumar, Anil

    2015-04-30

    Hammett acidity function observes the effect of protonation/deprotonation on the optical density/absorbance of spectrophotometric indicator. In this work, the Hammett acidity, H0, of equimolar mixtures of aqueous HCOOH, CH3COOH, and CH3CH2COOH was measured in 1-methylimidazolium-, 1-methylpyrrolidinium-, and 1-methylpiperidinium-based protic ionic liquids (PILs) and 1-butyl-3-methylimidazolium-based aprotic ionic liquid (AIL) with formate (HCOO(-)) anion. Higher H0 values were observed for the equimolar mixtures of aqueous carboxylic acids in protic ionic liquids compared with those of the aprotic ionic liquid because of the involvement of the stronger specific interactions between the conjugate acid of ionic liquid and conjugate base of carboxylic acids as suggested by the hard-soft acid base (HSAB) theory. The different H0 values for the equimolar mixtures of aqueous carboxylic acids in protic and aprotic ionic liquids were noted to depend on the activation energy of proton transfer (Ea,H(+)). The higher activation energy of proton transfer was obtained in AIL, indicating lower ability to form specific interactions with solute than that of PILs. Thermodynamic parameters determined by the "indicator overlapping method" further confirmed the involvement of the secondary interactions in the dissociation of carboxylic acids. On the basis of the thermodynamic parameter values, the potential of different ionic liquids in the dissociation of carboxylic acids was observed to depend on the hydrogen bond donor acidity (α) and hydrogen bond acceptor basicity (β), characteristics of specific interactions.

  3. MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

    Science.gov (United States)

    Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

  4. [Bim]Ac离子液体+醇二元混合体系的体积和黏度性质研究%Volumetric and Viscosity Properties of 1-Butylimidazolium Acetate Ionic Liquid/Methanol, Ethanol or 1-Propanol Binary Mixtures

    Institute of Scientific and Technical Information of China (English)

    许映杰; 俞超红; 鲁越青

    2015-01-01

    1-Butylimidazolium acetate ([Bim]Ac) ionic liquid was synthesized, and the structure was characterized by1H-NMR,13C-NMR, and IR spectroscopy. Density and viscosity of [Bim]Ac+methanol, [Bim]Ac+ethanol, and [Bim]Ac+1-propanol binary mixtures were measured over an entire range of molar fraction at T=303.15 K under atmospheric pressure using a vibrating U-shaped sample tube densimeter and Ubbelohde Suspended-level viscometer, respectively. Excess molar volumes (VE), apparent molar volumes (Vfi), partial molar volumes (Vm,i), and excess partial molar volumes (VEm,i) of the studied systems were calculated with the density data. Viscosity deviations (Δη) of the studied systems were obtained from the viscosity data.VE andΔηwere fitted by Redlich-Kister equation, respectively. The results show that theVE values of the three studied systems are negative over the entire composition range, and a minimum value is reached with mole fraction of [Bim]Acx1=0.3~0.4. TheΔηvalues of the above-mentioned systems are also negative over the entire composition range, and a minimum value is reached withx1=0.4~0.5. TheVE orΔη values of the studied systems follow an order of [Bim]Ac+methanol < [Bim]Ac+ethanol < [Bim]Ac+1-propanol, which indicates that the interaction between [Bim]Ac and alkanol increases with the increase of alkanol polarity. TheVE andΔη values can be well fitted with Redlich-Kister equation.%合成了1-丁基咪唑醋酸盐([Bim]Ac)离子液体,通过1H-NMR、13C-NMR和IR对其结构进行了表征。在303.15 K和常压下,采用U形振荡管密度计测定了[Bim]Ac+甲醇、乙醇和正丙醇二元体系的密度,用乌氏黏度计测定了体系的黏度。由密度数据计算得到了体系的超额摩尔体积(VE)、表观摩尔体积(Vfi )、偏摩尔体积(V m,i )和超额偏摩尔体积( EV m,i ),由黏度数据获得了体系的混合黏度变化(∆h),并采用Redlich-Kister方程分别关联了VE、∆h与组成的关系。结果表明:

  5. Computation of the acoustic nonlinearity parameter in organic liquid binary mixtures

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on Jacobson's molecular free length theory in liquids and the relationship between the ultrasonic velocity and the molecular free length in organic liquids,the equation of the acoustic nonlinearity parameter in organic liquid binary mixtures is derived.The calculated values from the equation are in good agreement both with those from Apfel's and from Sehgal's mixture laws.

  6. Enhanced selective extraction of hexane from hexane/soybean oil mixture using binary gas mixtures of carbon dioxide.

    Science.gov (United States)

    Eller, Fred J; Taylor, S L; Palmquist, Debra E

    2007-04-18

    Carbon dioxide (CO2) can effectively separate hexane from a mixture of soybean oil (SBO) and hexane with a slight coextraction of SBO. Previous research demonstrated that CO2 entrained with helium significantly reduced SBO solubility in CO2. In this study, CO2 was mixed with three gases (He, N2, or Ar) (0.5-30 vol %) to decrease SBO solubility while attempting to maintain hexane solubility. The binary gas mixtures (at 25 degrees C and 9.31 MPa) were passed through a 25 wt % hexane/SBO mixture inside a 2.5 m fractionation column. Coextracted SBO was inversely proportional to binary gas concentration, whereas residual hexane in the raffinate was proportional to binary gas concentration. The 10% binary mixture of N2 or Ar was the best compromise to obtain both low residual hexane levels (i.e., 26 ppm) and low SBO coextraction (i.e., only 40 mg). This carry-over of SBO represents a 95% reduction in SBO carry-over compared to neat CO2.

  7. Measurement and modelling of hydrogen bonding in 1-alkanol plus n-alkane binary mixtures

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Jensen, Lars; Kofod, Jonas L.;

    2007-01-01

    Two equations of state (simplified PC-SAFT and CPA) are used to predict the monomer fraction of 1-alkanols in binary mixtures with n-alkanes. It is found that the choice of parameters and association schemes significantly affects the ability of a model to predict hydrogen bonding in mixtures, even...... studies, which is clarified in the present work. New hydrogen bonding data based on infrared spectroscopy are reported for seven binary mixtures of alcohols and alkanes. (C) 2007 Elsevier B.V. All rights reserved....

  8. Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

    Institute of Scientific and Technical Information of China (English)

    李新学; 刘迎新; 魏雄辉

    2005-01-01

    The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

  9. Ultrasonic study on organic liquid and binary organic liquid mixtures by using Schaaffs' collision factor theory

    Institute of Scientific and Technical Information of China (English)

    Lu Yi-Gang; Dong Yan-Wu

    2006-01-01

    Based on Schaaff's collision factor theory (CFT) in liquids, the equations for nonlinear ultrasonic parameters in both organic liquid and binary organic liquid mixtures are deduced. The nonlinear ultrasonic parameters, including pressure coefficient, temperature coefficients of ultrasonic velocity, and nonlinear acoustic parameter B/A in both organic liquid and binary organic liquid mixtures, are evaluated for comparison with the measured results and data from other sources. The equations show that the coefficient of ultrasonic velocity and nonlinear acoustic parameter B/A are closely related to molecular interactions. These nonlinear ultrasonic parameters reflect some information of internal structure and outside status of the medium or mixtures. From the exponent of repulsive forces of the molecules,several thermodynamic parameters, pressure and temperature of the medium, the nonlinear ultrasonic parameters and ultrasonic nature of the medium can be evaluated. When evaluating and studying nonlinear acoustic parameter B/A of binary organic liquid mixtures, there is no need to know the nonlinear acoustic parameter B/A of the components.Obviously, the equation reveals the connection between the nonlinear ultrasonic nature and internal structure and outside status of the mixtures more directly and distinctly than traditional mixture law for B/A, e.g. Apfel's and Sehgal's laws for liquid binary mixtures.

  10. Ternary liquid–liquid equilibria for mixtures of toluene + n-heptane + an ionic liquid

    NARCIS (Netherlands)

    Meindersma, G. Wytze; Podt, Anita J.G.; Haan, de André B.

    2006-01-01

    This research has been focused on a study of sulfolane and four ionic liquids as solvents in liquid–liquid extraction. Liquid–liquid equilibria data were obtained for mixtures of (sulfolane or 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]BF4) or 1-ethyl-3-methylimidazolium ethylsulfate ([em

  11. Densities of Pure Ionic Liquids and Mixtures: Modeling and Data Analysis

    DEFF Research Database (Denmark)

    Abildskov, Jens; O’Connell, John P.

    2015-01-01

    Our two-parameter corresponding states model for liquid densities and compressibilities has been extended to more pure ionic liquids and to their mixtures with one or two solvents. A total of 19 new group contributions (5 new cations and 14 new anions) have been obtained for predicting pressure...

  12. Heat capacities of the mixtures of ionic liquids with acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Waliszewski, Dariusz, E-mail: waliszew@uni.lodz.p [Department of Physical Chemistry, University of Lodz, Pomorska 165, PL-90 236 Lodz (Poland); Piekarski, Henryk [Department of Physical Chemistry, University of Lodz, Pomorska 165, PL-90 236 Lodz (Poland)

    2010-02-15

    Isobaric specific heat capacities were measured for left brace1-hexyl-3-methylimidazolium tetrafluoroborate (HMIMBF{sub 4}) + acetonitrile (MeCN)right brace and left brace1-methyl-3-octylimidazolium tetrafluoroborate (OMIMBF{sub 4}) + acetonitrileright brace within the whole range of composition and temperatures from (283.15 to 323.15) K. The excess molar heat capacities were calculated from the experimental results and satisfactorily fitted to Redlich-Kister type polynomials for several selected temperatures. Negative deviations from the additivity of molar heat capacities were observed within the whole composition range of (HMIBMF{sub 4} + MeCN) and (OMIMBF{sub 4} + MeCN). The results obtained have been interpreted in terms of interactions between ionic liquids and acetonitrile.

  13. Transport properties of supercritical fluids and their binary mixtures

    CERN Document Server

    Luedemann, H D

    2002-01-01

    The molecular dynamics of the two supercritical fluids most applied in industry and some of their mixtures are characterized by their self-diffusion coefficients D sub i , measured by high pressure high resolution nuclear magnetic resonance with the strengthened glass cell technique. The technical details of the apparatus will be given. The fluids studied are carbon dioxide and ammonia. For CO sub 2 , mixtures with C sub 6 H sub 6 , H sub 2 , CH sub 3 COOH and CH sub 3 OH were investigated. The NH sub 3 mixtures include C sub 6 H sub 6 , (CH sub 3) sub 3 N, CH sub 3 CN and CH sub 3 OH.

  14. Adsorption at the liquid-vapor surface of a binary liquid mixture

    Science.gov (United States)

    Whitmer, J. K.; Kiselev, S. B.; Law, B. M.

    2005-11-01

    In a binary liquid mixture, the component possessing the lowest surface tension preferentially adsorbs at the liquid-vapor surface. In the past this adsorption behavior has been extensively investigated for critical binary liquid mixtures near the mixture's critical temperature Tc. In this fluctuation-dominated regime the adsorption is described by a universal function of the dimensionless depth z /ξ where ξ is the bulk correlation length. Fewer studies have quantitatively examined adsorption for off-critical mixtures because, in this case, one must carefully account for both the bulk and surface crossover from the fluctuation-dominated regime (close to Tc) to the mean-field dominated regime (far from Tc). In this paper we compare extensive liquid-vapor ellipsometric adsorption measurements for the mixture aniline+cyclohexane at a variety of critical and noncritical compositions with the crossover theory of Kiselev and co-workers [J. Chem. Phys. 112, 3370 (2000)].

  15. Ionic-Liquid Based Separation of Azeotropic Mixtures

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2014-01-01

    such as stability, toxicity, and environmental impacts of the ILs. A Hildebrand solubility parameter group contribution model for ILs is highlighted to screen the miscibility of the ILs with the target solute component which was considered as a key target property to further screen the candidates from the previous...... on minimum concentration of the ILs required to break the given azeotrope, the best ILs as entrainers for water + ethanol and water + isopropanol azeotropic mixtures were [C1MIM][DMP] and [C2MIM][N(CN)2], respectively....

  16. Thermodynamic coarsening arrested by viscous fingering in partially miscible binary mixtures

    Science.gov (United States)

    Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

    2016-09-01

    We study the evolution of binary mixtures far from equilibrium, and show that the interplay between phase separation and hydrodynamic instability can arrest the Ostwald ripening process characteristic of nonflowing mixtures. We describe a model binary system in a Hele-Shaw cell using a phase-field approach with explicit dependence of both phase fraction and mass concentration. When the viscosity contrast between phases is large (as is the case for gas and liquid phases), an imposed background flow leads to viscous fingering, phase branching, and pinch off. This dynamic flow disorder limits phase growth and arrests thermodynamic coarsening. As a result, the system reaches a regime of statistical steady state in which the binary mixture is permanently driven away from equilibrium.

  17. High-frequency sound wave propagation in binary gas mixtures flowing through microchannels

    Science.gov (United States)

    Bisi, M.; Lorenzani, S.

    2016-05-01

    The propagation of high-frequency sound waves in binary gas mixtures flowing through microchannels is investigated by using the linearized Boltzmann equation based on a Bhatnagar-Gross-Krook (BGK)-type approach and diffuse reflection boundary conditions. The results presented refer to mixtures whose constituents have comparable molecular mass (like Ne-Ar) as well as to disparate-mass gas mixtures (composed of very heavy plus very light molecules, like He-Xe). The sound wave propagation model considered in the present paper allows to analyze the precise nature of the forced-sound modes excited in different gas mixtures.

  18. Phase equilibria in ionic liquid-aromatic compound mixtures, including benzene fluorination effects.

    Science.gov (United States)

    Blesic, Marijana; Lopes, José N Canongia; Pádua, Agílio A H; Shimizu, Karina; Gomes, Margarida F Costa; Rebelo, Luís Paulo N

    2009-05-28

    This work extends the scope of previous studies on the phase behavior of mixtures of ionic liquids with benzenes or its derivatives by determining the solid-liquid and liquid-liquid phase diagrams of mixtures containing an ionic liquid and a fluorinated benzene. The systems studied include 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide plus hexafluorobenzene or 1,3,5-trifluorobenzene and 1-ethyl-3-methylimidazolium triflate or N-ethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide plus benzene. The phase diagrams exhibit different kinds of solid-liquid behavior: the (usual) occurrence of eutectic points; the (not-so-usual) presence of congruent melting points and the corresponding formation of inclusion crystals; or the observation of different ionic liquid crystalline phases (polymorphism). These different types of behavior can be controlled by temperature annealing during crystallization or by the nature of the aromatic compound and can be interpreted, at a molecular level, taking into account the structure of the crystals or liquid mixtures, together with the unique characteristics of ionic liquids, namely the dual nature of their interactions with aromatic compounds.

  19. Communication: Unusual structure and transport in ionic liquid-hexane mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Min; Khatun, Sufia; Castner, Edward W., E-mail: ecastner@rci.rutgers.edu [Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 (United States)

    2015-03-28

    Ionic liquids having a sufficiently amphiphilic cation can dissolve large volume fractions of alkanes, leading to mixtures with intriguing properties on molecular length scales. The trihexyl(tetradecyl)phosphonium cation paired with the bis(trifluoromethylsulfonyl)amide anion provides an ionic liquid that can dissolve large mole fractions of hexane. We present experimental results on mixtures of n-C{sub 6}D{sub 14} with this ionic liquid. High-energy X-ray scattering studies reveal a persistence of the characteristic features of ionic liquid structure even for 80% dilution with n-C{sub 6}D{sub 14}. Nuclear magnetic resonance self-diffusion results reveal decidedly non-hydrodynamic behavior where the self-diffusion of the neutral, non-polar n-C{sub 6}D{sub 14} is on average a factor of 21 times faster than for the cation. Exploitation of the unique structural and transport properties of these mixtures may lead to new opportunities for designer solvents for enhanced chemical reactivity and interface science.

  20. Thermodynamic properties and diffusion of water + methane binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Shvab, I.; Sadus, Richard J., E-mail: rsadus@swin.edu.au [Centre for Molecular Simulation, Swinburne University of Technology, PO Box 218 Hawthorn, Victoria 3122 (Australia)

    2014-03-14

    Thermodynamic and diffusion properties of water + methane mixtures in a single liquid phase are studied using NVT molecular dynamics. An extensive comparison is reported for the thermal pressure coefficient, compressibilities, expansion coefficients, heat capacities, Joule-Thomson coefficient, zero frequency speed of sound, and diffusion coefficient at methane concentrations up to 15% in the temperature range of 298–650 K. The simulations reveal a complex concentration dependence of the thermodynamic properties of water + methane mixtures. The compressibilities, heat capacities, and diffusion coefficients decrease with increasing methane concentration, whereas values of the thermal expansion coefficients and speed of sound increase. Increasing methane concentration considerably retards the self-diffusion of both water and methane in the mixture. These effects are caused by changes in hydrogen bond network, solvation shell structure, and dynamics of water molecules induced by the solvation of methane at constant volume conditions.

  1. Thermodynamic studies of mixtures for topical anesthesia: Lidocaine-salol binary phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Lazerges, Mathieu [Laboratoire de Chimie Physique (EA 4066), Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, 4 Avenue de l' Observatoire, 75270 Paris Cedex 06 (France); Rietveld, Ivo B., E-mail: ivo.rietveld@parisdescartes.fr [Laboratoire de Chimie Physique (EA 4066), Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, 4 Avenue de l' Observatoire, 75270 Paris Cedex 06 (France); Corvis, Yohann; Ceolin, Rene; Espeau, Philippe [Laboratoire de Chimie Physique (EA 4066), Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, 4 Avenue de l' Observatoire, 75270 Paris Cedex 06 (France)

    2010-01-10

    The lidocaine-salol binary system has been investigated by differential scanning calorimetry, direct visual observations, and X-ray powder diffraction, resulting in a temperature-composition phase diagram with a eutectic equilibrium. The eutectic mixture, found at 0.423 {+-} 0.007 lidocaine mole-fraction, melts at 18.2 {+-} 0.5 {sup o}C with an enthalpy of 17.3 {+-} 0.5 kJ mol{sup -1}. This indicates that the liquid phase around the eutectic composition is stable at room temperature. Moreover, the undercooled liquid mixture does not easily crystallize. The present binary mixture exhibits eutectic behavior similar to the prilocaine-lidocaine mixture in the widely used EMLA topical anesthetic preparation.

  2. Surface tension of decane binary and ternary mixtures with eicosane, docosane, and tetracosane

    DEFF Research Database (Denmark)

    Queimada, Antonio; Cao, A.I.; Marrucho, I.M.

    2005-01-01

    -C24H50 and the ternary n-C10H22 + n-C20H42 + n-C24H50 were measured from 293.15 K (or above the solution melting temperature) up to 343.15 K. An average absolute deviation of 1.3% was obtained in comparison with pure component literature data. No mixture information for the reported systems was found......A tensiometer operating on the Wilhelmy plate method was employed to measure liquid-vapor interfacial tensions of three binary mixtures and one ternary mixture of decane with eicosane, docosane, and tetracosane. Tensions of binary mixtures n-C10H22 + n-C20H42, n-C10H22 + n-C22H46, and n-C10H22 + n...

  3. Mixtures of protic ionic liquids and molecular cosolvents: a molecular dynamics simulation.

    Science.gov (United States)

    Docampo-Álvarez, Borja; Gómez-González, Víctor; Méndez-Morales, Trinidad; Carrete, Jesús; Rodríguez, Julio R; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

    2014-06-07

    In this work, the effect of molecular cosolvents (water, ethanol, and methanol) on the structure of mixtures of these compounds with a protic ionic liquid (ethylammonium nitrate) is analyzed by means of classical molecular dynamics simulations. Included are as-yet-unreported measurements of the densities of these mixtures, used to test our parameterized potential. The evolution of the structure of the mixtures throughout the concentration range is reported by means of the calculation of coordination numbers and the fraction of hydrogen bonds in the system, together with radial and spatial distribution functions for the various molecular species and molecular ions in the mixture. The overall picture indicates a homogeneous mixing process of added cosolvent molecules, which progressively accommodate themselves in the network of hydrogen bonds of the protic ionic liquid, contrarily to what has been reported for their aprotic counterparts. Moreover, no water clustering similar to that in aprotic mixtures is detected in protic aqueous mixtures, but a somehow abrupt replacing of [NO3](-) anions in the first hydration shell of the polar heads of the ionic liquid cations is registered around 60% water molar concentration. The spatial distribution functions of water and alcohols differ in the coordination type, since water coordinates with [NO3](-) in a bidentate fashion in the equatorial plane of the anion, while alcohols do it in a monodentate fashion, competing for the oxygen atoms of the anion. Finally, the collision times of the different cosolvent molecules are also reported by calculating their velocity autocorrelation functions, and a caging effect is observed for water molecules but not in alcohol mixtures.

  4. Sub-shock formation in Grad 10-moment equations for a binary gas mixture

    Science.gov (United States)

    Bisi, Marzia; Conforto, Fiammetta; Martalò, Giorgio

    2016-09-01

    The shock structure problem for Grad 10-moment equations for an inert binary mixture is investigated: necessary conditions for the formation of sub-shocks in fields of only one gas or of both components are rigorously obtained, and a detailed comparison with the shock-wave structure of its principal sub-system (deduced assuming vanishing viscous stress tensors) and of the equilibrium Euler sub-system is performed. Some numerical simulations for a mixture of argon and helium are presented.

  5. Non-linearity parameter / of binary liquid mixtures at elevated pressures

    Indian Academy of Sciences (India)

    J D Pandey; J Chhabra; R Dey; V Sanguri; R Verma

    2000-09-01

    When sound waves of high amplitude propagate, several non-linear effects occur. Ultrasonic studies in liquid mixtures provide valuable information about structure and interaction in such systems. The present investigation comprises of theoretical evaluation of the acoustic non-linearity parameter / of four binary liquid mixtures using Tong and Dong equation at high pressures and = 303.15 K. Thermodynamic method has also been used to calculate the non-linearity parameter after making certain approximations.

  6. Excess molar enthalpies of binary mixtures containing mono- and polybromoalkanes at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, S.T.; Munoz, J.; Velasco, I.; Otin, S. [Univ. de Zaragoza (Spain). Dept. de Quimica Organica y Quimica Fisica

    1995-05-01

    An isobaric and quasi-isothermic calorimeter has been used to determine excess molar enthalpies, H{sub m}{sup E}, at 298.15 K and atmospheric pressure for 10 binary mixtures containing dibromomethane, tribromomethane, 1,2-dibromoethane, 1,1,2,2-tetrabromoethane, and 1-bromopropane. H{sub m}{sup E} values for these mixtures are negative except for 1,2-dibromoethane or dibromomethane + 1-bromopropane and 1,1,2,2-tetrabromoethane + tribromomethane.

  7. The extraction of aromatic amino acids with binary and ternary mixtures of hydrophilic solvents

    Science.gov (United States)

    Mokshina, N. Ya.; Pakhomova, O. A.; Niftaliev, S. I.

    2007-11-01

    The extraction of tyrosine and phenylalanine with binary and ternary mixtures of hydrophilic solvents from aqueous salt solutions was studied, and several tendencies were observed. Simplex-lattice planning of experiment was used for the optimization of the composition of solvent mixtures. It was shown that the extraction systems developed could be employed for the almost complete extraction of tyrosine and phenylalanine from aqueous solutions.

  8. Microwave dielectric characterization of binary mixture of formamide with , -dimethylaminoethanol

    Indian Academy of Sciences (India)

    Prabhakar Undre; S N Helambe; S B Jagadale; P W Khirade; S C Mehrotra

    2007-05-01

    Dielectric relaxation measurements of formamide (FMD)–,- dimethylaminoethanol (DMAE) solvent mixtures have been carried out over the entire concentration range using time domain reflectometry technique at 25, 35 and 45° C in thefrequency range of 10 MHz to 20 GHz. The mixtures exhibit a principle dispersion of the Davidson–Cole relaxation type at microwave frequencies. Bilinear calibration method is used to obtain complex permittivity *() from complex reflection coefficient ρ*() over the frequency range of 10 MHz to 10 GHz. The excess permittivity (E), excessinverse relaxation time (1/)E, Kirkwood correlation factor (eff), activation energy and Bruggeman factor (B) are also calculated to study the solute–solvent interaction.

  9. Improving enzymatic production of diglycerides by engineering binary ionic liquid medium system.

    Science.gov (United States)

    Guo, Zheng; Kahveci, Derya; Ozçelik, Beraat; Xu, Xuebing

    2009-10-01

    The tunable property of ionic liquids (ILs) offers tremendous opportunity to rethink the strategy of current efforts to resolve technical challenges that occurred in many production approaches. To establish an efficient glycerolysis approach for enzymatic production of diglycerides (DG), this work reported a novel concept to improve DG yield by applying a binary IL system that consisted of one IL with better DG production selectivity and another IL being able to achieve higher conversion of triglycerides (TG). The candidates for combination were determined by individually examining lipase-catalyzed glycerolysis in different ILs, as a result, promising ones are divided into two groups based on their reaction specificities. The effects of parametric variables were then preliminarily evaluated, following a further investigation of the reaction performance in different binary IL systems from cross-group combinations. The combination of TOMA.Tf(2)N/Ammoeng 102 was employed for optimization by Response Surface Methodology. Eighty to eighty-five percent (mol%) of oil conversion and up to 90% (mol%) of total DG yield (73%, wt%) were obtained, which are markedly higher than those previously reported. This work demonstrated the practical feasibility to couple the technical advantage (high TG conversion and high DG production selective in this work) of individual ILs into a binary system to over-perform the reaction. It is believed that binary IL system could be also applicable to other enzymatic reaction systems for establishment of more efficient reaction protocols.

  10. Prediction of mechanical properties of compacted binary mixtures containing high-dose poorly compressible drug.

    Science.gov (United States)

    Patel, Sarsvatkumar; Bansal, Arvind Kumar

    2011-01-17

    The aim of the study was to develop, compare and validate predictive model for mechanical property of binary systems. The mechanical properties of binary mixtures of ibuprofen (IBN) a poorly compressible high dose drug, were studied in presence of different excipients. The tensile strength of tablets of individual components viz. IBN, microcrystalline cellulose (MCC), and dicalcium phosphate dihydrate (DCP) and binary mixtures of IBN with excipients was measured at various relative densities. Prediction of the mechanical property of binary mixtures, from that of single components, was attempted using Ryshkewitch-Duckworth (R-D) and Percolation theory, by assuming a linear mixing rule or a power law mixing rule. The models were compared, and the best model was proposed based on the distribution of residuals and the Akaike's information criterion. Good predictions were obtained with the power law combined with linear mixing rule, using R-D and Percolation models. The results indicated that the proposed model can well predict the mechanical properties of binary system containing predominantly poorly compressible drug candidate. The predictions of these models and conclusions can be systematically generalized to other pharmaceutical powders.

  11. Liquid crystalline behaviour of mixtures of structurally dissimilar mesogens in binary systems

    Indian Academy of Sciences (India)

    Jayrang S Dave; Meera R Menon; Pratik R Patel

    2002-06-01

    We have studied four binary systems comprising four ester components, viz. 4-nitrophenyl-4'--alkoxybenzoates (where -alkoxy is nbutoxy, C4, -hexyloxy, C6, -octyloxy, C8 and -decyloxy, C10) and one azo component, 4--decyloxy phenylazo-4'-isoamyloxy benzene. A variety of mesomorphic properties are observed in these mixtures. The properties of these systems are discussed on the basis of phase diagrams.

  12. Self-Propulsion Mechanism of Active Janus Particles in Near-Critical Binary Mixtures

    NARCIS (Netherlands)

    Samin, Sela; van Roij, Rene

    2015-01-01

    Gold-capped Janus particles immersed in a near-critical binary mixture can be propelled using illumination. We employ a nonisothermal diffuse interface approach to investigate the self-propulsion mechanism of a single colloid. We attribute the motion to body forces at the edges of a micronsized drop

  13. Non-isothermal diffusion in a binary mixture with smoothed particle hydrodynamics

    NARCIS (Netherlands)

    Thieulot, C; Espanol, P

    2005-01-01

    We explore the possibility of controlling the pattern formation in a purely diffusive binary mixture described by a van der Waals equation of state in non-isothermal situations. Simulations are conducted with a previously formulated thermodynamically consistent smoothed particle hydrodynamics model

  14. Excess Molar Volumes and Viscosities of Binary Mixture of Diethyl Carbonate+Ethanol at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    MA Peisheng; LI Nannan

    2005-01-01

    The purpose of this work was to report excess molar volumes and dynamic viscosities of the binary mixture of diethyl carbonate (DEC)+ethanol. Densities and viscosities of the binary mixture of DEC+ethanol at temperatures 293.15 K-343.15 K and atmospheric pressure were determined over the entire composition range. Densities of the binary mixture of DEC+ethanol were measured by using a vibrating U-shaped sample tube densimeter. Viscosities were determined by using Ubbelohde suspended-level viscometer. Densities are accurate to 1.0×10-5 g·cm-3, and viscosities are reproducible within ±0.003 mPa·s. From these data, excess molar volumes and deviations in viscosity were calculated. Positive excess molar volumes and negative deviations in viscosity for DEC+ethanol system are due to the strong specific interactions.All excess molar vo-lumes and deviations in viscosity fit to the Redlich-Kister polynomial equation.The fitting parameters were presented,and the average deviations and standard deviations were also calculated.The errors of correlation are very small.It proves that it is valuable for estimating densities and viscosities of the binary mixture by the correlated equation.

  15. Surface tension of heptane, decane, hexadecane, eicosane, and some of their binary mixtures

    DEFF Research Database (Denmark)

    Rolo, Lara I.; Caco, Ana I.; Queimada, Antonio;

    2002-01-01

    Surface tension measurements were performed by the Wilhelmy plate method. Measured systems included pure heptane, decane, hexadecane, eicosane, and some of their binary mixtures at temperatures from 293.15 K to 343.15 K with an average absolute deviation of 1.6%. The results were compared with a ...

  16. Sedimentation-diffusion equilibrium of binary mixtures of charged colloids including volume effects

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Lyklema, J.

    2005-01-01

    We describe the sedimentation-diffusion equilibrium of binary mixtures of charged colloids in the presence of small ions and for non-dilute conditions, by extending the work of Biben and Hansen (1994 J. Phys.: Condens. Matter 6 A345). For a monocomponent system, they included a Carnahan-Starling har

  17. Resistances for heat and mass transfer through a liquid–vapor interface in a binary mixture

    NARCIS (Netherlands)

    Glavatskiy, K.S.; Bedeaux, D.

    2010-01-01

    In this paper we calculate the interfacial resistances to heat and mass transfer through a liquid–vapor interface in a binary mixture. We use two methods, the direct calculation from the actual nonequilibrium solution and integral relations, derived earlier. We verify, that integral relations, being

  18. Validity of the Onsager relations in relativistic binary mixtures.

    Science.gov (United States)

    Moratto, Valdemar; Garcia-Perciante, A L; Garcia-Colin, L S

    2011-08-01

    In this work we study the properties of a relativistic mixture of two nonreacting dilute species in thermal local equilibrium. Following the conventional ideas in kinetic theory, we use the concept of chaotic velocity. In particular, we address the nature of the density, or pressure gradient term that arises in the solution of the linearized Boltzmann equation in this context. Such an effect, also present for the single component problem, has, so far, not been analyzed from the point of view of the Onsager resciprocity relations. To address this matter, we propose two alternatives for the onsagerian matrix which comply with the corresponding reciprocity relations. The implications of both representations are briefly analyzed.

  19. The effects of binary UV filter mixtures on the midge Chironomus riparius

    Energy Technology Data Exchange (ETDEWEB)

    Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis, E-mail: jlmartinez@ccia.uned.es

    2016-06-15

    Organic ultraviolet (UV) filters are used in a wide variety of products, including cosmetics, to prevent damage from UV light in tissues and industrial materials. Their extensive use has raised concerns about potential adverse effects in human health and aquatic ecosystems that accumulate these pollutants. To increase sun radiation protection, UV filters are commonly used in mixtures. Here, we studied the toxicity of binary mixtures of 4-methylbenzylidene camphor (4MBC), octyl-methoxycinnamate (OMC), and benzophenone-3 (BP-3), by evaluating the larval mortality of Chironomus riparius. Also molecular endpoints have been analyzed, including alterations in the expression levels of a gene related with the endocrine system (EcR, ecdysone receptor) and a gene related with the stress response (hsp70, heat shock protein 70). The results showed that the mortality caused by binary mixtures was similar to that observed for each compound alone; however, some differences in LC50 were observed between groups. Gene expression analysis showed that EcR mRNA levels increased in the presence of 0.1 mg/L 4MBC but returned to normal levels after exposure to mixtures of 4MBC with 0.1, 1, and 10 mg/L of BP-3 or OMC. In contrast, the hsp70 mRNA levels increased after exposure to the combinations tested of 4MBC and BP-3 or OMC mixtures. These data suggest that 4MBC, BP-3, and OMC may have antagonist effects on EcR gene transcription and a synergistic effect on hsp70 gene activation. This is the first experimental study to show the complex patterned effects of UV filter mixtures on invertebrates. The data suggest that the interactions within these chemicals mixtures are complex and show diverse effects on various endpoints. - Highlights: • Chironomus riparius is sensitive to UV filter binary mixtures. • UV filters binary mixtures show antagonism on survival of 4th instar larvae. • BP-3 and OMC antagonize the stimulatory effect of 4MBC on EcR gene. • 4MBC, OMC, and BP-3 induce hsp70

  20. Ultrasonic Investigations of Molecular Interaction in Binary Mixtures of Benzyl Benzoate with Acetonitrile and Benzonitrile

    Directory of Open Access Journals (Sweden)

    N. Jaya Madhuri

    2011-01-01

    Full Text Available Ultrasonic velocity, density and viscosity have been measured in the binary mixtures of benzyl benzoate with acetonitrile, benzonitrile at three temperatures 30, 40 and 50 °C. From the experimental data, thermodynamic parameters like adiabatic compressibility, internal pressure, enthalpy, activation energy etc., were computed and the molecular interactions were predicted based on the variation of excess parameters in the mixture. Also theoretical evaluation of velocities was made employing the standard theories. CFT and NOMOTO were found to have an edge. All the three mixtures have shown out strong intermolecular interactions between the unlike molecules and endothermic type of chemical reaction.

  1. Ultrasonic study of molecular interaction in binary liquid mixtures at 30°C

    Indian Academy of Sciences (India)

    A Ali; A K Nain

    2002-04-01

    Densities ρ and ultrasonic speeds of the binary mixtures of tetrahydrofuran (THF) with 1-butanol and tert-butanol, at 30°C, over the entire composition range were measured. From these data isentropic compressibility, s, intermolecular free length f, relative association A, acoustic impedance , molar sound speed m, deviations in isentropic compressibility s, and excess volume E were calculated. The variation of these parameters with composition of the mixture helps us in understanding the nature and extent of interaction between unlike molecules in the mixtures. Further, theoretical values of ultrasonic speed were evaluated using theories and empirical relations. The relative merits of these theories and relations were discussed.

  2. Biosorption of binary mixtures of Cr(III and Cu(II ions by Sargassum sp

    Directory of Open Access Journals (Sweden)

    Silva E.A.

    2003-01-01

    Full Text Available The adsorption of two metal ions, Cr(III and Cu(II, in single-component and binary systems by Sargassum sp., a brown alga, was studied. Equilibrium batch sorption studies were carried out at 30ºC and pH 3.5. Kinetic tests were done for a binary mixture (chromium + copper for a contact time of 72 hours to guarantee that equilibrium was reached. The monocomponent equilibrium data obtained were analyzed using the Langmuir and Freundlich isotherms. The binary equilibrium data obtained were described using four Langmuir-type and Freundlich isotherms. The F-test showed a statistically significant fit for all binary isotherm models. The parameters for isotherms of the Langmuir-type were used to determine the affinity of one metal for the biosorbent in the presence of another metal. The chromium ion showed a greater affinity for Sargassum sp. than the copper ion.

  3. Toxic effect of metal cation binary mixtures to the seaweed Gracilaria domingensis (Gracilariales, Rhodophyta).

    Science.gov (United States)

    Mendes, Luiz Fernando; Stevani, Cassius Vinicius; Zambotti-Villela, Leonardo; Yokoya, Nair Sumie; Colepicolo, Pio

    2014-01-01

    The macroalga Gracilaria domingensis is an important resource for the food, pharmaceutical, cosmetic, and biotechnology industries. G. domingensis is at a part of the food web foundation, providing nutrients and microelements to upper levels. As seaweed storage metals in the vacuoles, they are considered the main vectors to magnify these toxic elements. This work describes the evaluation of the toxicity of binary mixtures of available metal cations based on the growth rates of G. domingensis over a 48-h exposure. The interactive effects of each binary mixture were determined using a toxic unit (TU) concept that was the sum of the relative contribution of each toxicant and calculated using the ratio between the toxicant concentration and its endpoint. Mixtures of Cd(II)/Cu(II) and Zn(II)/Ca(II) demonstrated to be additive; Cu(II)/Zn(II), Cu(II)/Mg(II), Cu(II)/Ca(II), Zn(II)/Mg(II), and Ca(II)/Mg(II) mixtures were synergistic, and all interactions studied with Cd(II) were antagonistic. Hypotheses that explain the toxicity of binary mixtures at the molecular level are also suggested. These results represent the first effort to characterize the combined effect of available metal cations, based on the TU concept on seaweed in a total controlled medium. The results presented here are invaluable to the understanding of seaweed metal cation toxicity in the marine environment, the mechanism of toxicity action and how the tolerance of the organism.

  4. Controlled structuring of binary hard-disk mixtures via a periodic, external potential.

    Science.gov (United States)

    Franzrahe, K; Nielaba, P

    2009-05-01

    Ordering phenomena on surfaces or in monolayers can be successfully studied by model systems as binary hard-disk mixtures, the influence of a substrate being modeled by an external potential. For the field-free case the thermodynamic stability of space-filling lattice structures for binary hard-disk mixtures is studied by Monte Carlo computer simulations. As these structures prove to be thermodynamically stable only in high pressure environments, the phase behavior of an equimolar binary mixture with a diameter ratio of sigma_{B}/sigma_{A}=0.414 exposed to an external, one-dimensional, periodic potential is analyzed in detail. The underlying ordering mechanisms and the resulting order differ considerably, depending on which components of the mixture interact with the external potential. The simulations show that slight deviations in the concentration of large particles x_{A} or the diameter ratio sigma_{B}/sigma_{A} have no impact on the occurrence of the various field-induced phenomena as long as the mixture stays in the relevant regime of the packing fraction eta . Furthermore the importance of the commensurability of the external potential to the S1(AB) square lattice for the occurrence of the induced ordering is discussed.

  5. Phase Diagrams and Ordering in Charged Membranes: Binary Mixtures of Charged and Neutral Lipids.

    Science.gov (United States)

    Shimokawa, Naofumi; Himeno, Hiroki; Hamada, Tsutomu; Takagi, Masahiro; Komura, Shigeyuki; Andelman, David

    2016-07-07

    We propose a model describing the phase behavior of two-component membranes consisting of binary mixtures of electrically charged and neutral lipids. We take into account the structural phase transition (main-transition) of the hydrocarbon chains, and investigate the interplay between this phase transition and the lateral phase separation. The presence of charged lipids significantly affects the phase behavior of the multicomponent membrane. Due to the conservation of lipid molecular volume, the main-transition temperature of charged lipids is lower than that of neutral ones. Furthermore, as compared with binary mixtures of neutral lipids, the membrane phase separation in binary mixtures of charged lipids is suppressed, in accord with recent experiments. We distinguish between two types of charged membranes: mixtures of charged saturated lipid/neutral unsaturated lipid and a second case of mixtures of neutral saturated lipid/charged unsaturated lipid. The corresponding phase behavior is calculated and shown to be very different. Finally, we discuss the effect of added salt on the phase separation and the temperature dependence of the lipid molecular area.

  6. Rheology and Structure of Quenched Binary Mixtures Under Oscillatory Shear

    Institute of Scientific and Technical Information of China (English)

    XU Ai-Guo

    2003-01-01

    We applied the D2Q9 BGK lattice Boltzmann method to study the rheology and structure of the phaseseparating binary fluids under oscillatory shear in the diffusive regime. The method is suitable for simulating systemswhose dynamicsis described by the Navier-Stokes equation and convection-diffusion equation. The shear oscillationinduces different rheological patterns from those under steady shear. With the increasing of the frequency of the shearthe system shows more isotropic behavior, while with the decreasing of the frequency we find more configurations similarto those under steady shear. By decreasing the frequency of the shear, the period of the applied flow becomes thesame order of the relaxation time of the shear velocity profile, which is inversely proportional to the viscosity, and moreanisotropic effects become observable. The structure factor and the velocity profile contribute to the understanding ofthe configurations and the kinetic process. Oscillatory shear induces nonlinear pattern of the horizontal velocity profile.Therefore, configurations are found where lamellar order close to the wall coexists with isotropic domains in the middleof the system. For very slow frequencies, the morphology of the domains is characterized by lamellar order everywherethat resembles what happens in the case of steady shear.

  7. Convection in Binary Fluid Mixtures; 2, Localized Traveling Waves

    CERN Document Server

    Barten, W; Kamps, M; Schmitz, R

    1995-01-01

    Nonlinear, spatially localized structures of traveling convection rolls are investigated in quantitative detail as a function of Rayleigh number for two different Soret coupling strengths (separation ratios) with Lewis and Prandtl numbers characterizing ethanol-water mixtures. A finite-difference method was used to solve the full hydrodynamic field equations numerically. Structure and dynamics of these localized traveling waves (LTW) are dominated by the concentration field. Like in the spatially extended convective states ( cf. accompanying paper), the Soret-induced concentration variations strongly influence, via density changes, the buoyancy forces that drive convection. The spatio-temporal properties of this feed-back mechanism, involving boundary layers and concentration plumes, show that LTW's are strongly nonlinear states. Light intensity distributions are determined that can be observed in side-view shadowgraphs. Detailed analyses of all fields are made using colour-coded isoplots, among others. In th...

  8. Low Mach Number Fluctuating Hydrodynamics of Binary Liquid Mixtures

    CERN Document Server

    Nonaka, A J; Bell, J B; Donev, A

    2014-01-01

    Continuing on our previous work [ArXiv:1212.2644], we develop semi-implicit numerical methods for solving low Mach number fluctuating hydrodynamic equations appropriate for modeling diffusive mixing in isothermal mixtures of fluids with different densities and transport coefficients. We treat viscous dissipation implicitly using a recently-developed variable-coefficient Stokes solver [ArXiv:1308.4605]. This allows us to increase the time step size significantly compared to the earlier explicit temporal integrator. For viscous-dominated flows, such as flows at small scales, we develop a scheme for integrating the overdamped limit of the low Mach equations, in which inertia vanishes and the fluid motion can be described by a steady Stokes equation. We also describe how to incorporate advanced higher-order Godunov advection schemes in the numerical method, allowing for the treatment of fluids with high Schmidt number including the vanishing mass diffusion coefficient limit. We incorporate thermal fluctuations in...

  9. Excess molar volumes and isentropic compressibilities of binary liquid mixtures containing n-alkanes at 298.15 K

    Indian Academy of Sciences (India)

    V Vyas; T Nautiyal

    2002-10-01

    Excess molar volumes (E) and deviation in isentropic compressibilities (s) have been investigated from the density and speed of sound measurements of six binary liquid mixtures containing -alkanes over the entire range of composition at 298.15 K. Excess molar volume exhibits inversion in sign in one binary mixture, i.e., n-heptane + n-hexane. Remaining five binary mixtures, n-heptane + toluene, cyclohexane + n-heptane, cyclohexane + n-hexane, toluene + nhexane and n-decane + n-hexane show negative excess molar volumes over the whole composition range. However, the large negative values of excess molar volume becomes dominant in toluene + n-hexane mixture. Deviation in isentropic compressibility is negative over the whole range of composition in the case of all the six binary mixtures. Existence of specific intermolecular interactions in the mixtures has been analyzed in terms of excess molar volume and deviation in isentropic compressibility.

  10. Ionic conductivity of binary fluorides of potassium and rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Sorokin, N. I., E-mail: nsorokin1@yandex.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2016-01-15

    The ionic conductivity s of KYF{sub 4} and K{sub 2}RF{sub 5} single crystals (R = Gd, Ho, Er) and KNdF{sub 4} and K{sub 2}RF{sub 5} ceramic samples (R = Dy, Er) has been studied in the temperature range of 340–500°C. A comparative analysis of the σ values for these objects has been performed. Binary fluorides of potassium and rare earth elements were synthesized by the hydrothermal method (temperature 480°C, pressure 100–150 MPa) in the R{sub 2}O{sub 3}–KF–H{sub 2}O systems. The σ values of tetraf luorides are 3 × 10{sup –5} S/cm (KYF{sub 4} single crystal) and 3 × 10{sup –6} S/cm (KNdF{sub 4} ceramics) at 435°C. A K{sub 2}ErF{sub 5} single crystal with σ = 1.2 × 10{sup –4} S/cm at 435°C has the maximum value of ionic conductivity among pentafluorides. The anisotropy of ionic transport was found in K{sub 2}HoF{sub 5} single crystals, σ{sub ∥c}/σ{sub ⊥c} = 2.5, where σ{sub ∥c} and σ{sub ⊥c} are, respectively, the conductivities along the crystallographic c axis and in the perpendicular direction.

  11. MODELING VAPOR LIQUID EQUILIBRIUM OF IONIC LIQUIDS plus GAS BINARY SYSTEMS AT HIGH PRESSURE WITH CUBIC EQUATIONS OF STATE

    OpenAIRE

    Freitas, ACD; Cunico, LP; M. Aznar; Guirardello,R.

    2013-01-01

    Ionic liquids (IL) have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (v...

  12. Gamma-radiation-induced grafting of binary mixture of methacrylic acid and 4-vinyl pyridine onto Teflon-FEP film as an effective polar membrane for separation processes

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Inderjeet [Department of Chemistry, H.P. University, Shimla 171005 (India); Rattan, Sunita [Amity School of Engineering and Technology, New Delhi (India); Chauhan, Sandeep [Department of Chemistry, H.P. University, Shimla 171005 (India); Gupta, Nitika, E-mail: nitikaguptahpu@yahoo.co.i [Department of Chemistry, H.P. University, Shimla 171005 (India)

    2010-05-15

    Ionic bifunctional membranes have been synthesized by grafting binary mixture of methacrylic acid (MAAc) and 4-vinyl pyridine (4-VP) onto Teflon-FEP film by pre-irradiation method. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters. Maximum percentage of grafting of binary mixture (MAAc-co-4-VP) (71.29%) was obtained at an optimum total dose of 54.48 kGy and the total concentration was 9.49 mol/L ([4-VP] = 0.07 mol/L and [MAAc ] = 9.42 mol/L) in 5 ml of water. The effect of alcohols as additives to the reaction medium on percent grafting of the binary mixture has also been studied. The membranes were characterized by FTIR spectroscopy, scanning electron microscopy and thermogravimetric analysis. Swelling studies of the membranes were performed in different solvents such as water, benzene, carbon tetrachloride and dimethyl formamide (DMF). Maximum swelling was observed in DMF with minimum swelling in benzene. Metal ion (Cu{sup 2+}, Ni{sup 2+} and Fe{sup 2+}) uptake studies show better affinity for Fe{sup 2+} ions. Conductance measurements in different aqueous salt solution showed that these membranes have affinity for Na{sup +}/K{sup +} ions and Cl{sup -} ions and hence can be used in desalination/separation processes for the separation of both type of cationic and anionic ions.

  13. Prediction of the Flash Point of Binary and Ternary Straight-Chain Alkane Mixtures

    Directory of Open Access Journals (Sweden)

    X. Li

    2014-01-01

    Full Text Available The flash point is an important physical property used to estimate the fire hazard of a flammable liquid. To avoid the occurrence of fire or explosion, many models are used to predict the flash point; however, these models are complex, and the calculation process is cumbersome. For pure flammable substances, the research for predicting the flash point is systematic and comprehensive. For multicomponent mixtures, especially a hydrocarbon mixture, the current research is insufficient to predict the flash point. In this study, a model was developed to predict the flash point of straight-chain alkane mixtures using a simple calculation process. The pressure, activity coefficient, and other associated physicochemical parameters are not required for the calculation in the proposed model. A series of flash points of binary and ternary mixtures of straight-chain alkanes were determined. The results of the model present consistent experimental results with an average absolute deviation for the binary mixtures of 0.7% or lower and an average absolute deviation for the ternary mixtures of 1.03% or lower.

  14. Binary mixtures of hydrogen-bonded ferroelectric liquid crystals. Thermal span enhancement in smectic X* phase

    Energy Technology Data Exchange (ETDEWEB)

    Sangameswari, Gopal; Prabu, Nataraj Pongali Sathya; Madhu Mohan, Mathukumalli Lakshmi Narayana [Bannari Amman Institute of Technology, Sathyamangalam (India). Liquid Crystal Research Laboratory (LCRL)

    2015-07-01

    Thermotropic hydrogen-bonded ferroelectric binary liquid crystal mixtures comprising of N-carbamyl-l-glutamic acid (CGA) and p-n-alkyloxy benzoic acids (BAO) are investigated. Variation in the molar proportion of X and Y (where X=CGA+5BAO and Y=CGA+9BAO, CGA+10BAO, CGA+11BAO, and CGA+12BAO) comprising of four series yielded 36 binary mixtures. Optical and thermal properties of these mixtures are meticulously studied in the present article. In addition to the traditional phases, a novel smectic ordering namely smectic X* is observed in all the four series. The aim of the investigation is to obtain abundance occurrence of smectic X* with a large thermal span, and hence, the proportions of the binary mixtures are so chosen that the prelude task is accomplished. Optical tilt angle in smectic X* and smectic C* phases is experimentally determined, and a theoretical fit is performed. Phase diagrams of the four series are constructed from the data obtained from the differential scanning calorimetry and correlated with the phases recorded by the polarising optical microscope studies. Thermal stability factor and thermal equilibrium are also premeditated.

  15. Induced smectic phases in phase diagrams of binary nematic liquid crystal mixtures.

    Science.gov (United States)

    Huang, Tsang-Min; McCreary, Kathleen; Garg, Shila; Kyu, Thein

    2011-03-28

    To elucidate induced smectic A and smectic B phases in binary nematic liquid crystal mixtures, a generalized thermodynamic model has been developed in the framework of a combined Flory-Huggins free energy for isotropic mixing, Maier-Saupe free energy for orientational ordering, McMillan free energy for smectic ordering, Chandrasekhar-Clark free energy for hexagonal ordering, and phase field free energy for crystal solidification. Although nematic constituents have no smectic phase, the complexation between these constituent liquid crystal molecules in their mixture resulted in a more stable ordered phase such as smectic A or B phases. Various phase transitions of crystal-smectic, smectic-nematic, and nematic-isotropic phases have been determined by minimizing the above combined free energies with respect to each order parameter of these mesophases. By changing the strengths of anisotropic interaction and hexagonal interaction parameters, the present model captures the induced smectic A or smectic B phases of the binary nematic mixtures. Of particular importance is the fact that the calculated phase diagrams show remarkable agreement with the experimental phase diagrams of binary nematic liquid crystal mixtures involving induced smectic A or induced smectic B phase.

  16. Composition dependent non-ideality in aqueous binary mixtures as a signature of avoided spinodal decomposition

    Indian Academy of Sciences (India)

    Sarmistha Sarkar; Saikat Banerjee; Susmita Roy; Rikhia Ghosh; Partha Pratim Ray; Biman Bagchi

    2015-01-01

    We explore the potential energy landscape of structure breaking binary mixtures (SBBM) where two constituents dislike each other, yet remain macroscopically homogeneous at intermediate to high temperatures. Interestingly, we find that the origin of strong composition dependent non-ideal behaviour lies in its phase separated inherent structure. The inherent structure (IS) of SBBM exhibits bi-continuous phase as is usually formed during spinodal decomposition.We draw analogy of this correlation between non-ideality and phase separation in IS to explain observation of non-ideality in real aqueous mixtures of small amphiphilic solutes, containing both hydrophilic and hydrophobic groups. Although we have not been able to obtain IS of these liquids, we find that even at room temperature these liquids sustain formation of fluctuating, transient bicontinuous phase, with limited lifetime ( ≲ 20 ps). While in the model (A, B) binary mixture, the non-ideal composition dependence can be considered as a fluctuation from a phase separated state, a similar scenario is expected to be responsible for the unusually strong non-ideality in these aqueous binary mixtures.

  17. Monolayer and bilayer structures in ionic liquids and their mixtures confined to nano-films.

    Science.gov (United States)

    Smith, Alexander M; Lovelock, Kevin R J; Perkin, Susan

    2013-01-01

    The confinement of liquids to thin films can lead to dramatic changes in their structural arrangement and dynamic properties. Ionic liquids display nano-structures in the bulk of the liquid, consisting of polar and non-polar domains, whereas a solid surface can induce layered structures in the near-surface liquid. Here we compare and contrast the layer structures in a series of imidazolium and pyrrolidinium-based ionic liquids upon confinement of the liquids to films of approximately 0-20 nm between two negatively charged mica surfaces. Using a surface force balance (SFB) we measured the force between the two atomically smooth mica surfaces with ionic liquid between, directly revealing the ion packing and dimensions of layered structures for each liquid. The ionic liquids with shorter alkyl chain substituents form alternating cation-anion monolayer structures on confinement, whilst a longer alkyl chain leads to alignment of the cations in bilayer formation. The crossover from monolayers to bilayers, however, occurs at different alkyl chain lengths for imidazolium- and pyrrolidinium-based ionic liquids with a common anion. In addition, we find that imidazolium cation bilayers are arranged in toe-to-toe orientation, whereas pyrrolidinium cations form bilayers consisting of fully interdigitated alkyl chains. Results for a mixture of monolayer-preferring (i.e. short alkyl chain) and bilayer-preferring (i.e. long alkyl chain) liquids indicate alkyl chain segregation and bilayer-like structures. We discuss the driving forces for these self-assembly effects, and the contrasting behaviour of the imidazolium and pyrrolidinium-type ionic liquids.

  18. Interfacial tensions of binary mixtures of ethanol with octane, decane, dodecane, and tetradecane

    Energy Technology Data Exchange (ETDEWEB)

    Mejia, Andres, E-mail: amejia@udec.cl [Departamento de Ingenieria Quimica, Universidad de Concepcion, P.O. Box 160-C, Correo 3, Concepcion (Chile); Cartes, Marcela [Departamento de Ingenieria Quimica, Universidad de Concepcion, P.O. Box 160-C, Correo 3, Concepcion (Chile); Segura, Hugo, E-mail: hsegura@udec.cl [Departamento de Ingenieria Quimica, Universidad de Concepcion, P.O. Box 160-C, Correo 3, Concepcion (Chile)

    2011-09-15

    Highlights: > Experimental interfacial tensions in binary mixtures with aneotropic behavior. > Experimental interfacial tensions for ethanol + hydrocarbon mixtures. > Aneotropic displacement in ethanol mixtures. - Abstract: This contribution is devoted to the experimental characterization of interfacial tensions of a representative group of binary mixtures pertaining to the (ethanol + linear hydrocarbon) series (i.e. octane, decane, dodecane, and tetradecane). Experimental measurements were isothermically performed using a maximum differential bubble pressure technique, which was applied over the whole mole fraction range and over the temperature range 298.15 K < T/K < 318.15 K. Experimental results show that the interfacial tensions of (ethanol + octane or decane) negatively deviate from the linear behavior and that sharp minimum points on concentration, or aneotropes, are observed for each isotherm. The interfacial tensions of (ethanol + dodecane or tetradecane), in turn, are characterized by combined deviations from the linear behavior, and inflecting behavior observed on concentration for each isotherm. The experimental evidence also shows that these latter mixtures are close to exhibit aneotropy. For the case of (ethanol + octane or decane) mixtures, aneotropy was clearly induced by the similarity of the interfacial tension values of the constituents. The inflecting behavior of the interfacial tensions of (ethanol + dodecane or tetradecane), in turn, was observed in the vicinity of the coordinates of the critical point of these mixtures, thus pointing to the fact that the quasi-aneotropic singularity that affects these mixtures was provoked by the proximity of an immiscibility gap of the liquid phase. Finally, the experimental data of interfacial tensions were smoothed with the Scott-Myers expansion, from which it is possible to conclude that the observed aneotropic concentrations weakly depend on temperature for all the analyzed mixtures.

  19. Density, viscosity and phase equilibria study of {ethylsulfate-based ionic liquid + water} binary systems as a function of temperature and composition

    Energy Technology Data Exchange (ETDEWEB)

    Królikowska, Marta, E-mail: mlaskowska@ch.pw.edu.pl; Lipiński, Paweł; Maik, Daria

    2014-04-01

    Highlights: • The [EMPIP][EtSO{sub 4}], [EMMOR][EtSO{sub 4}], [EMPYR][EtSO{sub 4}] and its aqueous mixtures have been studied. • The density, dynamic viscosity and SLE have been determined. • The excess molar volumes and viscosity deviations have been calculated. • The NRTL, Wilson, UNIQUAC, Redlich–Kister and VFT equations have been used to correlate the experimental data. - Abstract: This paper is a continuation of our investigation on physicochemical and thermodynamic properties of ionic liquids and its aqueous solutions. In this work the density, ρ and dynamic viscosity, η have been determined for binary mixtures of the ionic liquids: 1-ethyl-1-methyl-piperidinium ethylsulfate, [EMPIP][EtSO{sub 4}], 1-ethyl-1-methylmorpholinium ethylsulfate, [EMMOR][EtSO{sub 4}] and 1-ethyl-1-methylpyrrolidinium ethylsulfate, [EMPYR][EtSO{sub 4}] with water at wide temperature and composition range at atmospheric pressure. From experimental values of the density, ρ and dynamic viscosity, η the excess molar volumes, V{sup E} and viscosity deviations, Δη were calculated and correlated using Redlich–Kister polynomial equation. The (solid + liquid) phase equilibria, SLE for the tested binary mixtures have been determined by well-known dynamic method at a wide range of composition and temperature at atmospheric pressure. For comparison, the SLE data for {[EMPYR][EtSO_4] + water} binary mixtures have been determined using DSC technique. The experimental SLE data have been correlated by means of NRTL, UNIQUAC and Wilson equations. Additionally, the basic thermal properties of the pure ILs, that is, the glass-transition temperature, T{sub g,1} as well as the heat capacity at the glass-transition temperature, ΔC{sub p(g),1}, melting temperature, T{sub m} and enthalpy of melting, Δ{sub m}H have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the ILs was detected by the simultaneous TG/DTA experiments. The choice of the

  20. Physical properties and solubility parameters of 1-ethyl-3-methylimidazolium based ionic liquids/DMSO mixtures at 298.15 K

    Science.gov (United States)

    Saba, H.; Yumei, Z.; Huaping, W.

    2015-12-01

    Densities, refractive indices, conductivities and viscosities of binary mixtures of 1-ethyl-3-methylimidazolium-based ionic liquids (ILs) with dimethyl sulfoxide at 298.15 K are reported. Excess molar volumes have been calculated from experimental data and were fitted with Redlich-Kister equation. The density and refractive index were found to increase with increasing concentration in all cases except [EMIM]COOH. The free mobility of ions has found to enhance conductivity and decrease viscosity to varying extent in all mixtures being studied. It has been observed that solubility parameters, dielectric constants and nature of anions of ILs being used play a vital role in determining the subsequent characteristics. As DMSO has high dielectric constant therefore, it was able to form interactions with most of ILs except with [EMIM]COOH due to anomalous nature of anion.

  1. Nanostructure of mixtures of protic ionic liquids and lithium salts: effect of alkyl chain length.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; Rodríguez, Julio R; Cabeza, Óscar; Gallego, Luis J; Russina, Olga; Varela, Luis M

    2015-02-21

    The bulk structure of mixtures of two protic ionic liquids, propylammonium nitrate and butylammonium nitrate, with a salt with a common anion, is analyzed at room temperature by means of small angle X-ray scattering and classical molecular dynamics simulations. The study of several structural properties, such as density, radial distribution functions, spatial distribution functions, hydrogen bonds, coordination numbers and velocity autocorrelation functions, demonstrates that increasing the alkyl chain length of the alkylammonium cation results in more segregated, better defined polar and apolar domains, the latter having a larger size. This increase, ascribed to the erosion of the H-bond network in the ionic liquid polar regions as salt is added, is confirmed by means of small angle X-ray scattering measurements, which show a clear linear increase of the characteristic spatial sizes of the studied protic ionic liquids with salt concentration, similar to that previously reported for ethylammonium nitrate (J. Phys. Chem. B, 2014, 118, 761-770). In addition, larger ionic liquid cations lead to a lower degree of hydrogen bonding and to more sparsely packed three-dimensional structures, which are more easily perturbed by the addition of lithium salts.

  2. Assessment of combined antiandrogenic effects of binary parabens mixtures in a yeast-based reporter assay.

    Science.gov (United States)

    Ma, Dehua; Chen, Lujun; Zhu, Xiaobiao; Li, Feifei; Liu, Cong; Liu, Rui

    2014-05-01

    To date, toxicological studies of endocrine disrupting chemicals (EDCs) have typically focused on single chemical exposures and associated effects. However, exposure to EDCs mixtures in the environment is common. Antiandrogens represent a group of EDCs, which draw increasing attention due to their resultant demasculinization and sexual disruption of aquatic organisms. Although there are a number of in vivo and in vitro studies investigating the combined effects of antiandrogen mixtures, these studies are mainly on selected model compounds such as flutamide, procymidone, and vinclozolin. The aim of the present study is to investigate the combined antiandrogenic effects of parabens, which are widely used antiandrogens in industrial and domestic commodities. A yeast-based human androgen receptor (hAR) assay (YAS) was applied to assess the antiandrogenic activities of n-propylparaben (nPrP), iso-propylparaben (iPrP), methylparaben (MeP), and 4-n-pentylphenol (PeP), as well as the binary mixtures of nPrP with each of the other three antiandrogens. All of the four compounds could exhibit antiandrogenic activity via the hAR. A linear interaction model was applied to quantitatively analyze the interaction between nPrP and each of the other three antiandrogens. The isoboles method was modified to show the variation of combined effects as the concentrations of mixed antiandrogens were changed. Graphs were constructed to show isoeffective curves of three binary mixtures based on the fitted linear interaction model and to evaluate the interaction of the mixed antiandrogens (synergism or antagonism). The combined effect of equimolar combinations of the three mixtures was also considered with the nonlinear isoboles method. The main effect parameters and interaction effect parameters in the linear interaction models of the three mixtures were different from zero. The results showed that any two antiandrogens in their binary mixtures tended to exert equal antiandrogenic activity

  3. Grafting of vinyl acetate-ethylacrylate binary monomer mixture onto guar gum.

    Science.gov (United States)

    Singh, Vandana; Singh, Angela; Joshi, Sneha; Malviya, Tulika

    2016-03-01

    Present article reports on guar gum (GG) functionalization through graftcopolymerization of vinylacetate (VAC) and ethylacrylate (EA) from their binary mixtures. The potassium persulfate/ascorbic acid (KPS/AA) redox initiator system has been used for the binary grafting under the previously optimized conditions for VAC grafting at guar gum. The concentration of ascorbic acid (AA), persulfate (KPS), and grafting temperature were varied to optimize the binary grafting. A preliminary investigation revealed that the copolymer has excellent ability to capture Hg(II) from aqueous solution. It was observed that the optimum % grafting sample (CP3) was best at Hg(II) adsorption. CP3 and mercury loaded CP3 (CP3-Hg) have been extensively characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Thermo gravimetric analysis (TGA) and a plausible mechanism for the grafting has been proposed.

  4. Viscosities of binary mixtures of toluene with butan-1-ol and 2-methylpropan-2-ol

    Directory of Open Access Journals (Sweden)

    VASILE DUMITRESCU

    2005-11-01

    Full Text Available The viscosities of binary liquid mixtures of toluene with butan-1-ol and 2-methylpropan-2-ol have been determined at 298.15, 303.15, 308.15, 313.15 and 318.15 K over the whole concentration range. The Hind, Grunberg–Nissan, Wijk, Auslander and McAllister models were used to calculate the viscosity coefficients and these were compared with the experimental data for the mixtures. Excess viscosities were also calculated and fitted to the Redlich–Kister equation. Various thermodynamic properties of viscous flow activation were determined and their variations with composition are discussed.

  5. Estimation of Thermodynamic Properties of Binary Liquid Mixtures on the Basis of Statistical Mechanical Theories

    Directory of Open Access Journals (Sweden)

    J. D. Pandey

    2012-12-01

    Full Text Available Thermodynamic properties of liquids and liquid mixtures play very important role in understanding the nature of molecular interactions occurring in the system. In the present work different thermodynamic properties of 15 pure liquids and 34 equimolar binary liquid mixtures of benzene, toluene, p-xylene, chlorobenzene and 1-chloronaphthalene with linear and branched alkanes have been computed with the help of Flory’s statistical theory (FST, Hard sphere equation of state (HSE and Hole theory (HT simultaneously. The calculated values are compared with the experimental findings collected from literature and quite satisfactory results are obtained.

  6. Capillary condensation of a binary mixture in slit-like pores.

    Science.gov (United States)

    Bucior, Katarzyna; Patrykiejew, Andrzej; Pizio, Orest; Sokołowski, Stefan

    2003-03-15

    We investigate the capillary condensation of two model fluid mixtures in slit-like pores, which exhibit different demixing properties in the bulk phase. The interactions between adsorbate particles are modeled by using Lennard-Jones (12,6) potentials and the adsorbing potentials are of the Lennard-Jones (9,3) type. The calculations are performed for different pore widths and at different concentrations of the bulk gas, by means of density functional theory. We evaluate the capillary phase diagrams and discuss their dependence on the parameters of the model. Our calculations indicate that a binary mixture confined to a slit-like pore may exhibit rich phase behavior.

  7. Detection And Discrimination Of Pure Gases And Binary Mixtures Using A Single Microcantilever

    Energy Technology Data Exchange (ETDEWEB)

    Loui, A; Sirbuly, D J; Elhadj, S; McCall, S K; Hart, B R; Ratto, T V

    2009-08-06

    A new method for detecting and discriminating pure gases and binary mixtures has been investigated. This approach combines two distinct physical mechanisms within a single piezoresistive microcantilever: heat dissipation and resonant damping in the viscous regime. An experimental study of the heat dissipation mechanism indicates that the sensor response is directly correlated to the thermal conductivity of the gaseous analyte. A theoretical data set of resonant damping was generated corresponding to the gas mixtures examined in the thermal response experiments. The combination of the thermal and resonant response data yields more distinct analyte signatures that cannot otherwise be obtained from the detection modes individually.

  8. Total Reflux Operation of Multivessel Batch Distillation for Separation of Binary Mixtures

    Institute of Scientific and Technical Information of China (English)

    唐克; 白鹏; 李广忠

    2014-01-01

    Multivessel batch distillation (MVBD) is mainly used to separate mixtures with more than two compo-nents. In this article, a new operation mode with MVBD is proposed for separation of binary mixtures under total reflux. A mathematic model is setup for the simulation. The proposed operation policy and the regular operation with constant reflux are compared theoretically and experimentally. The results show that the new operation mode has great advantages in time saving and operation flexibility. MVBD presents great potential for separation with high efficiency.

  9. Low-temperature behaviour of the Kob-Andersen binary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Ashwin S S; Sastry, Srikanth [Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur Campus, Bangalore 560064 (India)

    2003-03-26

    The dynamical behaviours of glass-forming liquids have been analysed extensively via computer simulations of model liquids, among which the Kob-Andersen binary Lennard-Jones mixture has been a widely studied system. Typically, studies of this model have been restricted to temperatures above the mode coupling temperature. Preliminary results concerning the dynamics of the Kob-Andersen binary mixture are presented at temperatures that extend below the mode coupling temperature, along with properties of the local energy minima sampled. These results show that a crossover in the dynamics occurs alongside changes in the properties of the inherent structures sampled. Furthermore, a crossover is observed from non-Arrhenius behaviour of the diffusivity above the mode coupling temperature to Arrhenius behaviour at lower temperatures.

  10. Excess Molar Volume of Binary Mixtures of Methylheptenone+Alkanols at 298.15 K

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Excess molar volume(VE) data on binary liquid mixtures of methylheptenone (MHO) with methanol, ethanol, n-propanol or n-butanol have been determined from the density measurements at 298.15 K and atmospheric pressure. The values of VE in all the systems over the entire composition range are quantified by the Redlich-Kister equation. The effects of the chain length of alkanols on VE are discussed.

  11. Spectrophotometric determination of acidity constants of some macrolides in acetonitrile-water binary mixtures.

    Science.gov (United States)

    Sanli, Senem; Sanli, Nurullah; Alsancak, Güleren

    2010-12-01

    The acidity constants of eight macrolides (erythromycin, roxithromycin, oleandomycin, azithromycin, josamycin, tylosin tartrate, tilmicosin and spiramycin) have been determined in acetonitrile-water binary mixtures (30%, 40% and 50% (v/v)) by spectrophotometric method. The pKa's available in literature determined by various methods are compiled in comparison with the value of this work. These results are expected to essentially facilitate the research on occurrence, fate and effects, analysis method development, and control of antibiotics in various treatment occurrences.

  12. Viscosities of Binary Mixtures Containing Isomeric Chlorobutanes and Diisopropylether: Experimental and Predicted Values

    Science.gov (United States)

    Montaño, D.; Guerrero, H.; Bandrés, I.; López, M. C.; Lafuente, Carlos

    2010-03-01

    In this work, viscosities of binary mixtures of isomeric chlorobutanes with diisopropylether have been determined as a function of composition under atmospheric pressure and in the temperature range from 283.15 K to 313.15 K with steps of 5 K. Kinematics viscosities were measured using an Ubbelohde viscosimeter; absolute viscosities were obtained from kinematic viscosities and densities. Finally, we have used the Asfour method for predicting the dependence of viscosity with composition and comparing it with our experimental data.

  13. Experimental vapor-liquid equilibria data for binary mixtures of xylene isomers

    Directory of Open Access Journals (Sweden)

    W.L. Rodrigues

    2005-09-01

    Full Text Available Separation of aromatic C8 compounds by distillation is a difficult task due to the low relative volatilities of the compounds and to the high degree of purity required of the final commercial products. For rigorous simulation and optimization of this separation, the use of a model capable of describing vapor-liquid equilibria accurately is necessary. Nevertheless, experimental data are not available for all binaries at atmospheric pressure. Vapor-liquid equilibria data for binary mixtures were isobarically obtained with a modified Fischer cell at 100.65 kPa. The vapor and liquid phase compositions were analyzed with a gas chromatograph. The methodology was initially tested for cyclo-hexane+n-heptane data; results obtained are similar to other data in the literature. Data for xylene binary mixtures were then obtained, and after testing, were considered to be thermodynamically consistent. Experimental data were regressed with Aspen Plus® 10.1 and binary interaction parameters were reported for the most frequently used activity coefficient models and for the classic mixing rules of two cubic equations of state.

  14. Investigation of Boiling Heat Transfer of Binary Mixture from Vertical Tube Embedded in porous Media

    Institute of Scientific and Technical Information of China (English)

    HailongMo; TongzeMa; 等

    1996-01-01

    Ethanol-water binary mixtures with 7 different mole fractions of ethanol ranging from 0 to 1 were adopted as testing liquids in the experiment.The vertical heating tube was inserted in porous matrix composed of five well sorted glass beads whise diameters range from 0.5 to 4.3mm.Due to the effect of composition,the trend of combination of vapor bubbles was reduced.resulting in the increase of peak heat flux of binary mixture,With the increase of ethanol mole fraction,0.5mm diameter bead of peak heat flux of binary mixture.with the increase of ethanol mole fraction.0.5mm diameter bead had lower value of peak heat flux,while for pure liquid the critical state is difficult to appear,with given diameter of glass bead,there existed an optimum value of mole fraction of ethanol,which was decreased with the increase of bead diameter,A dimensionless heat transfer coefficient was predicted through the introduction of a dimensionless parameter of porous matrix which agreed with the experimental results satisfactorily.

  15. Cellulose Solubility in Ionic Liquid Mixtures: Temperature, Cosolvent, and Antisolvent Effects.

    Science.gov (United States)

    Minnick, David L; Flores, Raul A; DeStefano, Matthew R; Scurto, Aaron M

    2016-08-18

    Select ionic liquids (ILs) dissolve significant quantities of cellulose through disruption and solvation of inter- and intramolecular hydrogen bonds. In this study, thermodynamic solid-liquid equilibrium was measured with microcrystalline cellulose in a model IL, 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIm][DEP]) and mixtures with protic antisolvents and aprotic cosolvents between 40 and 120 °C. The solubility of cellulose in pure [EMIm][DEP] exhibits an asymptotic maximum of approximately 20 mass % above 100 °C. Solubility studies conducted on antisolvent mixtures with [EMIm][DEP] and [BMIm][Cl] indicate that protic solvents, ethanol, methanol, and water, significantly reduce the cellulose capacity of IL mixtures by 38-100% even at small antisolvent loadings (<5 mass %). Alternatively, IL-aprotic cosolvent (dimethyl sulfoxide, dimethylformamide, and 1,3-dimethyl-2-imidazolidinone) mixtures at mass ratios up to 1:1 enhance cellulose dissolution by 20-60% compared to pure [EMIm][DEP] at select temperatures. Interactions between the IL and molecular solvents were investigated by Kamlet-Taft solvatochromic analysis, FTIR, and NMR spectroscopy. The results indicate that preferential solvation of the IL cation and anion by co- and antisolvents impact the ability of IL ions to interact with cellulose thus affecting the cellulose dissolution capacity of IL-solvent mixtures.

  16. Composition and thermal analysis of binary mixtures of mee fat and palm stearin.

    Science.gov (United States)

    Abdul Manaf, Yanty Noorziana; Nazrim Marikkar, Jalaldeen Mohammed; Musthafa, Shuhaimi; Saari, Miskandar Mat

    2014-01-01

    Seed fat of Madhuca longifolia known as mee fat (MF) has been considered as a potential plant fat for producing fat mixture to simulate the properties of lard. A study was carried out to evaluate the effect of addition of palm stearin (PS) on the solidification behavior of MF to formulate a mixture to become similar in solidification characteristics of lard. Three fat mixtures were prepared by blending MF with palm stearin PS in different ratios: MF:PS (99.5:0.5), MF:PS (99:1), MF:PS (98:2) (w/w), and identified by the mass ratio of MF to PS. The fat mixtures were compared with lard in terms of their fatty acid and triacylglycerol compositions, differential scanning calorimetric (DSC) thermal profiles and solid fat content (SFC) characteristics. Results showed that there were considerable differences between lard and MF:PS fat mixtures with regard to fatty acid and triacylglycerol compositions. The increasing proportion of PS in MF:PS fat mixtures caused a general increase in SFC at different temperatures with respect to the SFC profile of native MF. Of the three binary mixtures, MF:PS (99:1) was found to show the least difference to lard in terms of SFC values throughout the temperature range.

  17. Spectroscopic and Chemometric Analysis of Binary and Ternary Edible Oil Mixtures: Qualitative and Quantitative Study.

    Science.gov (United States)

    Jović, Ozren; Smolić, Tomislav; Primožič, Ines; Hrenar, Tomica

    2016-04-19

    The aim of this study was to investigate the feasibility of FTIR-ATR spectroscopy coupled with the multivariate numerical methodology for qualitative and quantitative analysis of binary and ternary edible oil mixtures. Four pure oils (extra virgin olive oil, high oleic sunflower oil, rapeseed oil, and sunflower oil), as well as their 54 binary and 108 ternary mixtures, were analyzed using FTIR-ATR spectroscopy in combination with principal component and discriminant analysis, partial least-squares, and principal component regression. It was found that the composition of all 166 samples can be excellently represented using only the first three principal components describing 98.29% of total variance in the selected spectral range (3035-2989, 1170-1140, 1120-1100, 1093-1047, and 930-890 cm(-1)). Factor scores in 3D space spanned by these three principal components form a tetrahedral-like arrangement: pure oils being at the vertices, binary mixtures at the edges, and ternary mixtures on the faces of a tetrahedron. To confirm the validity of results, we applied several cross-validation methods. Quantitative analysis was performed by minimization of root-mean-square error of cross-validation values regarding the spectral range, derivative order, and choice of method (partial least-squares or principal component regression), which resulted in excellent predictions for test sets (R(2) > 0.99 in all cases). Additionally, experimentally more demanding gas chromatography analysis of fatty acid content was carried out for all specimens, confirming the results obtained by FTIR-ATR coupled with principal component analysis. However, FTIR-ATR provided a considerably better model for prediction of mixture composition than gas chromatography, especially for high oleic sunflower oil.

  18. The effects of binary UV filter mixtures on the midge Chironomus riparius.

    Science.gov (United States)

    Ozáez, Irene; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2016-06-15

    Organic ultraviolet (UV) filters are used in a wide variety of products, including cosmetics, to prevent damage from UV light in tissues and industrial materials. Their extensive use has raised concerns about potential adverse effects in human health and aquatic ecosystems that accumulate these pollutants. To increase sun radiation protection, UV filters are commonly used in mixtures. Here, we studied the toxicity of binary mixtures of 4-methylbenzylidene camphor (4MBC), octyl-methoxycinnamate (OMC), and benzophenone-3 (BP-3), by evaluating the larval mortality of Chironomus riparius. Also molecular endpoints have been analyzed, including alterations in the expression levels of a gene related with the endocrine system (EcR, ecdysone receptor) and a gene related with the stress response (hsp70, heat shock protein 70). The results showed that the mortality caused by binary mixtures was similar to that observed for each compound alone; however, some differences in LC50 were observed between groups. Gene expression analysis showed that EcR mRNA levels increased in the presence of 0.1mg/L 4MBC but returned to normal levels after exposure to mixtures of 4MBC with 0.1, 1, and 10mg/L of BP-3 or OMC. In contrast, the hsp70 mRNA levels increased after exposure to the combinations tested of 4MBC and BP-3 or OMC mixtures. These data suggest that 4MBC, BP-3, and OMC may have antagonist effects on EcR gene transcription and a synergistic effect on hsp70 gene activation. This is the first experimental study to show the complex patterned effects of UV filter mixtures on invertebrates. The data suggest that the interactions within these chemicals mixtures are complex and show diverse effects on various endpoints.

  19. Direct Conversion of Mono- and Polysaccharides into 5-Hydroxymethylfurfural Using Ionic-Liquid Mixtures.

    Science.gov (United States)

    Siankevich, Sviatlana; Fei, Zhaofu; Scopelliti, Rosario; Jessop, Philip G; Zhang, Jiaguang; Yan, Ning; Dyson, Paul J

    2016-08-23

    Platform chemicals are usually derived from petrochemical feedstocks. A sustainable alternative commences with lignocellulosic biomass, a renewable feedstock, but one that is highly challenging to process. Ionic liquids (ILs) are able to solubilize biomass and, in the presence of catalysts, convert the biomass into useful platform chemicals. Herein, we demonstrate that mixtures of ILs are powerful systems for the selective catalytic transformation of cellulose into 5-hydroxymethylfurfural (HMF). Combining ILs with continuous HMF extraction into methyl-isobutyl ketone or 1,2-dimethoxyethane, which form a biphase with the IL mixture, allows the online separation of HMF in high yield. This one-step process is operated under relatively mild conditions and represents a significant step forward towards sustainable HMF production.

  20. Effect of chain length of alcohol on thermodynamic properties of their binary mixtures with benzylalcohol

    Energy Technology Data Exchange (ETDEWEB)

    Venkatramana, L. [Department of Chemistry, P.V.K.N. Govt. Degree and P.G. College, Chittoor 517001, A.P. (India); Sivakumar, K. [Department of Chemistry, S.V. Arts Degree and P.G. College (T.T.D' S), Tirupati 517502, A.P. (India); Gardas, R.L., E-mail: gardas@iitm.ac.in [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India); Reddy, K. Dayananda, E-mail: ramanapvkn@gmail.com [Department of Chemistry, P.V.K.N. Govt. Degree and P.G. College, Chittoor 517001, A.P. (India)

    2014-04-01

    Highlights: • ρ and u have been measured for binary mixtures of benzylalcohol with 1-alkanols. • Experimental speed of sound data analyzed in terms of CFT and FLT. • V{sup E} for benzylalcohol with studied 1-alcohols are positive while κ{sub S}{sup E} are negative. - Abstract: Densities (ρ) of pure liquids and their mixtures have been measured over the entire composition range for the binary mixtures of benzylalcohol with 1-heptanol, 1-octanol, 1-nonanol and 1-decanol at 298.15 K to 313.15 K and at atmospheric pressure by using Rudolph Research Analytical Digital Density Meter (DDM-2911 model). Further, the speed of sound (u) for the above said mixtures were also measured at 303.15 K and 313.15 K. The experimental density data were used to compute excess molar volumes (V{sup E}) and compared with predictive expression proposed by Redlich–Kister equation. Excess speed of sound (u{sup E}), isentropic compressibility (κ{sub S}) and excess isentropic compressibilities (κ{sub S}{sup E}) were evaluated from experimental sound velocity and density data. Moreover, the experimental speed of sound data was compared in terms of theoretical models proposed by Schaaff's collision factor theory (CFT) and Jacobson's free length theory (FLT). The experimental results were discussed in terms of intermolecular interactions between component molecules.

  1. Ultrasonic Investigations of Molecular Interaction in Binary Mixtures of Cyclohexanone with Isomers of Butanol

    Directory of Open Access Journals (Sweden)

    Sk. Md Nayeem

    2014-01-01

    Full Text Available Ultrasonic speed, u, and density, ρ, have been measured in binary liquid mixtures of cyclohexanone with the isomers of butanol (n-butanol, sec-butanol, and tert-butanol at 308.15 K over the entire range of composition. Molar volume (Vm, adiabatic compressibility (ks, intermolecular free length (Lf, acoustic impedance (z, and their excess/deviation along with Δu have been calculated from the experimental data. These values have been fitted to Redlich-Kister type polynomial equation. Positive values of VmE, Δks, LfE and negative values of zE, Δu have been observed for all the liquid mixtures indicating the existence of weak interactions between components. Rupture of H-bond or reduction in H-bond strength of isomers of butanol or breaking of the structure of one or both of the components in a solution causes the existence of dispersions in the present investigated binary mixtures. The data obtained from V-m,1, V-m,2, and excess partial molar volumes V-m, 1E, V-m, 2E, reflects the inferences drawn from VmE. Furthermore, FTIR spectra support the conclusions drawn from excess/deviation properties. The measured values of ultrasonic speed for all the investigated mixtures have been compared with the theoretically estimated values using empirical relations such as, Nomoto, Van Dael and Vangeels, Impedance and Rao specific sound speed.

  2. Predicting the Solution Morphology of a Sulfonated Block Copolymer in Binary Solvent Mixtures

    Science.gov (United States)

    Griffin, Philip; Salmon, Grace; Ford, Jamie; Winey, Karen

    2015-03-01

    The physicochemical properties of solvent-casted block copolymer films are highly dependent on the microscopic morphology of the solutions from which they are cast. In order to achieve macroscopically homogenous polymer solutions, binary or higher-degree solvent mixtures are often required, which introduces additional complexity in understanding the molecular level interactions that control block copolymer self-assembly in solution. Using small angle x-ray scattering, we have explored the solution morphology in ternary blends of a sulfonated pentablock copolymer in select binary solvent mixtures over a range of solvent compositions and polymer concentrations. We have found that the solution morphologies in these ternary blends depend strongly on the composition of the solvent mixture. Furthermore, we demonstrate that the solvent-composition-dependent morphologies can be accurately predicted by quantifying the polymer/solvent interactions using Hansen solubility parameters. These studies are an important step toward developing a complete and predictive understanding of the solution morphology of complex polymer/solvent mixtures.

  3. Absorption spectra of e-beam-excited Ne, Ar, and Kr, pure and in binary mixtures.

    Science.gov (United States)

    Levchenko, A O; Ustinovskii, N N; Zvorykin, V D

    2010-10-21

    A technique using the broadband emission of a laser plume as probe radiation is applied to record UV-visible (190-510 nm) absorption spectra of Ne, Ar, and Kr, pure and in binary mixtures under moderate e-beam excitation up to 1 MW/cm(3). In all the rare gases and mixtures, the absorption spectra show continuum related to Rg(2) (+) homonuclear ions [peaking at λ∼285, 295, and 320 nm in Ne, Ar, and Kr(Ar/Kr), respectively] and a number of atomic lines related mainly to Rg(∗)(ms) levels, where m is the lowest principal quantum number of the valence electron. In argon, a continuum related to Ar(2) (∗) (λ∼325 nm) is also recorded. There are also trains of narrow bands corresponding to Rg(2) (∗)(npπ (3)Π(g))←Rg(2) (∗)(msσ (3)Σ(u) (+)) transitions. All the spectral features mentioned above were reported in literature but have never been observed simultaneously. Although charge transfer to a homonuclear ion of the heavier additive is commonly believed to dominate in binary rare-gas mixtures, it is found in this study that in Ne/Kr mixture, the charge is finally transferred from the buffer gas Ne(2) (+) ion not to Kr(2) (+) but to heteronuclear NeKr(+) ion.

  4. Surface tension of nitric oxide and its binary mixtures with krypton, methane, and ethene

    Energy Technology Data Exchange (ETDEWEB)

    Calado, J.C.G.; Santos Mendonca, A.F.S. dos; Saramago, B.J.V.; Soares, V.A.M. [Instituto Superior Tecnico, Lisbon (Portugal). Centro de Quimica Estrutural

    1997-05-15

    The surface tension of three binary liquid mixtures of NO with Kr, CH{sub 4}, and C{sub 2}H{sub 4} has been determined as a function of composition in the temperature range 102.0 to 119.0 K. These measurements are a contribution to the study of binary liquid mixtures in which one component is unassociated while the molecules of the other can associate between themselves. Nitric oxide is the simplest molecule capable of forming dimers, but not larger aggregates. This results in the surface tension of liquid nitric oxide having a strong temperature dependence: when the temperature increases the degree of dimerization decreases, contributing to a larger decrease of the surface tension. The surface tension of NO mixtures shows strong deviations from ideality. The mixtures containing Kr and CH{sub 4} exhibit negative deviations, while for the NO + C{sub 2}H{sub 4} system the surface tension shows a complex dependence on the composition. This strong departure from ideality had already been found for the bulk properties of these three systems. The surface tension of the CH{sub 4} + Kr system, already well characterized in the literature, was also measured to test the equipment.

  5. Cadmium-induced olfactory dysfunction in rainbow trout: Effects of binary and quaternary metal mixtures.

    Science.gov (United States)

    Dew, William A; Veldhoen, Nik; Carew, Amanda C; Helbing, Caren C; Pyle, Greg G

    2016-03-01

    A functioning olfactory response is essential for fish to be able to undertake essential behaviors. The majority of work investigating the effects of metals on the olfactory response of fish has focused on single-metal exposures. In this study we exposed rainbow trout to cadmium, copper, nickel, zinc, or a mixture of these four metals at or below the current Canadian Council of Ministers of the Environment guidelines for the protection of aquatic life. Measurement of olfactory acuity using an electro-olfactogram demonstrated that cadmium causes significant impairment of the entire olfactory system, while the other three metals or the mixture of all four metals did not. Binary mixtures with cadmium and each of the other metals demonstrated that nickel and zinc, but not copper, protect against cadmium-induced olfactory dysfunction. Testing was done to determine if the protection from cadmium-induced olfactory dysfunction could be explained by binding competition between cadmium and the other metals at the cell surface, or if the protection could be explained by an up-regulation of an intracellular detoxification pathway, namely metallothionein. This study is the first to measure the effects of binary and quaternary metal mixtures on the olfactory response of fish, something that will aid in future assessments of the effects of metals on the environment.

  6. Insights into synergistic interactions in binary mixtures of chemical permeation enhancers for transdermal drug delivery.

    Science.gov (United States)

    Karande, Pankaj; Jain, Amit; Mitragotri, Samir

    2006-09-28

    Chemical permeation enhancers (CPEs) are known to increase skin permeability to therapeutic drugs. Single chemicals, however, offer limited enhancements of skin permeability. Mixtures of chemicals can overcome this limitation owing to their synergistic interactions. However, identification of potent mixtures of chemicals requires screening of a large number of formulations. Discovery of CPE mixtures can be significantly accelerated by identifying patterns that occur in the existing data on CPEs. In this study, we systematically mine through a huge database on skin permeabilizing effect of over 4000 binary formulations generated by high throughput screening and extract general principles that govern the effect of binary combinations of chemicals on skin's barrier properties. Potencies and synergies of these formulations are analyzed to identify the role played by the formulation composition and chemistry. The analysis reveals several intuitive but some largely non-intuitive trends. For example, formulations made from enhancer mixtures are most potent when participating moieties are present in nearly equal fractions. Methyl pyrrolidone, a small molecule, is particularly effective in forming potent and synergistic enhancer formulations, and zwitterionic surfactants are more likely to feature in potent enhancers. Simple but invaluable rules like these will provide guiding principles for designing libraries to further speed up the formulation discovery process.

  7. Excess Transport Properties of Binary Mixtures of Quinoline with Xylenes at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Sk. Fakruddin

    2012-01-01

    Full Text Available The ultrasonic velocity and density of binary liquid mixtures of quinoline with o-xylene, m-xylene, and p-xylene have been measured over the entire range of composition at = 303.15, 308.15, 313.15, and 318.15 K. Using these data, various parameters like adiabatic compressibility (β, intermolecular free length (, and acoustic impedance ( and some excess parameters like excess adiabatic compressibility (, excess intermolecular free length (, excess acoustic impedance (, and excess ultrasonic velocity ( have been calculated for all the three mixtures. The calculated deviations and excess functions have been fitted to Redlich-Kister polynomial equation. The observed deviations have been explained on the basis of the intermolecular interactions present in these mixtures.

  8. Modeling diffusion coefficients in binary mixtures of polar and non-polar compounds

    DEFF Research Database (Denmark)

    Medvedev, Oleg; Shapiro, Alexander

    2005-01-01

    four temperature-independent parameters are required in order to describe the behavior of diffusion coefficients at different temperatures. The physical meaning of the parameters is analyzed. This makes it possible to reduce further their number to just two parameters for described mixtures with polar......The theory of transport coefficients in liquids, developed previously, is tested on a description of the diffusion coefficients in binary polar/non-polar mixtures, by applying advanced thermodynamic models. Comparison to a large set of experimental data shows good performance of the model. Only...... components and to only one parameter for mixtures consisting of non-polar components. A possibility of complete prediction of the parameters is discussed....

  9. Excess isentropic compressibility and speed of sound of the ternary mixture 2-propanol + diethyl ether + n-hexane and the constituent binary mixtures at 298.15 K

    Indian Academy of Sciences (India)

    Gokhan Sovaroglu; Ertunc Aral

    2006-02-01

    Speed of sound and densities of the ternary mixture 2-propanol + diethyl ether + n-hexane and also the binary mixtures 2-propanol + diethyl ether and 2-propanol + n-hexane have been measured at the entire composition range at 298.15 K. The excess isentropic compressibilities and the excess speed of the sound have been calculated from experimental densities and speed of sound. These excess properties of the binary mixtures were fitted to Redlich-Kister equation, while the Cibulka's equation was used to fit the values related to the values to the ternary system. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the binary mixtures and also the ternary mixtures. Speed of sound of the binary mixtures and the ternary mixture have been compared with calculated values from free length theory (FLT), collision factor theory (CFT), Nomoto's relation (NR), Van Deal's ideal mixing relation (IMR) and Junjie's relation (JR). The results are used to compare the relative merits of these theories and relations in terms of the root mean square deviation relative (RMSDr).

  10. Acute toxicity of binary and ternary mixtures of Cd, Cu, and Zn to Daphnia magna.

    Science.gov (United States)

    Meyer, Joseph S; Ranville, James F; Pontasch, Mandee; Gorsuch, Joseph W; Adams, William J

    2015-04-01

    Standard static-exposure acute lethality tests were conducted with Daphnia magna neonates exposed to binary or ternary mixtures of Cd, Cu, and Zn in moderately hard reconstituted water that contained 3 mg dissolved organic carbon/L added as Suwannee River fulvic acid. These experiments were conducted to test for additive toxicity (i.e., the response to the mixture can be predicted by combining the responses obtained in single-metal toxicity tests) or nonadditive toxicity (i.e., the response is less than or greater than additive). Based on total metal concentrations (>90% dissolved) the toxicity of the tested metal mixtures could be categorized into all 3 possible additivity categories: less-than-additive toxicity (e.g., Cd-Zn and Cd-Cu-Zn mixtures and Cd-Cu mixtures when Cu was titrated into Cd-containing waters), additive toxicity (e.g., some Cu-Zn mixtures), or more-than-additive toxicity (some Cu-Zn mixtures and Cd-Cu mixtures when Cd was titrated into Cu-containing waters). Exposing the organisms to a range of sublethal to supralethal concentrations of the titrated metal was especially helpful in identifying nonadditive interactions. Geochemical processes (e.g., metal-metal competition for binding to dissolved organic matter and/or the biotic ligand, and possibly supersaturation of exposure waters with the metals in some high-concentration exposures) can explain much of the observed metal-metal interactions. Therefore, bioavailability models that incorporate those geochemical (and possibly some physiological) processes might be able to predict metal mixture toxicity accurately.

  11. Structural transition in alcohol-water binary mixtures: A spectroscopic study

    Indian Academy of Sciences (India)

    Tuhin Pradhan; Piue Ghoshal; Ranjit Biswas

    2008-03-01

    The strengthening of the hydrogen bonding (H-bond) network as well as transition from the tetrahedral-like water network to the zigzag chain structure of alcohol upon increasing the alcohol concentration in ethanol-water and tertiary butanol (TBA) - water mixtures have been studied by using both steady state and time resolved spectroscopy. Absorption and emission characteristics of coumarin 153 (C153), a widely used non-reactive solvation probe, have been monitored to investigate the structural transition in these binary mixtures. The effects of the hydrogen bond (H-bond) network with alcohol concentration are revealed by a minimum in the peak frequency of the absorption spectrum of C153 which occur at alcohol mole fraction ∼ 0.10 for water-ethanol and at ∼ 0.04 for water-TBA mixtures. These are the mole fractions around which several thermodynamic properties of these mixtures show anomalous change due to the enhancement of H-bonding network. While the strengthening of H-bond network is revealed by the absorption spectra, the emission characteristics show the typical non-ideal alcohol mole fraction dependence at all concentrations. The time resolved anisotropy decay of C153 has been found to be bi-exponential at all alcohol mole fractions. The sharp change in slopes of average rotational correlation time with alcohol mole fraction indicates the structural transition in the environment around the rotating solute. The changes in slopes occur at mole fraction ∼ 0.10 for TBA-water and at ∼ 0.2 for ethanol-water mixtures, which are believed to reflect alcohol mole fraction induced structural changes in these alcohol-water binary mixtures.

  12. Dynamical properties of alcohol + 1-hexyl-3-methylimidazolium ionic liquid mixtures: a computer simulation study.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; García, Manuel; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M

    2011-12-29

    In this work, extensive molecular dynamics simulations of the dynamics of mixtures of ionic liquids (ILs) composed of the cation 1-hexyl-3-methylimidazolium and several anions of different hydrophobicity degrees (Cl(-), BF(4)(-), PF(6)(-)) with alcohols of different chain lengths (methanol and ethanol) are reported. We evaluated the influence of the nature of the anion, the length of the molecular chain of the alcohol, and the alcohol concentration on some dynamical properties of the mixtures, such as self-diffusion coefficients of all the species, mean square displacements (with an analysis of both ballistic and diffusive regimes), and velocity autocorrelation functions of alcohol molecules. The diffusivity of the mixtures was found to be highly dependent on the nature of the anion since the interaction between chloride and alcohols is greater than that with fluorinated anions and leads to slower dynamics. Additionally, our results show that self-diffusion coefficients increase with alcohol concentration. On the other hand, a subdiffusive regime over thousands of picoseconds was detected at intermediate times through analysis of the center-of-mass mean square displacements of alcohol molecules, a region that becomes narrower as alcohol concentration increases. Finally, the study of the role of the anion and of solvent concentration on velocity autocorrelation functions reflects an increase in mean collision times as the amount of alcohol increases until the value of pure alcohols is reached. These collision times are smaller in mixtures with halogenated ILs.

  13. New approach in modeling Cr(VI) sorption onto biomass from metal binary mixtures solutions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chang [College of Environmental Science and Engineering, Anhui Normal University, South Jiuhua Road, 189, 241002 Wuhu (China); Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Fiol, Núria [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Villaescusa, Isabel, E-mail: Isabel.Villaescusa@udg.edu [Chemical Engineering Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain); Poch, Jordi [Applied Mathematics Department, Escola Politècnica Superior, Universitat de Girona, Ma Aurèlia Capmany, 61, 17071 Girona (Spain)

    2016-01-15

    In the last decades Cr(VI) sorption equilibrium and kinetic studies have been carried out using several types of biomasses. However there are few researchers that consider all the simultaneous processes that take place during Cr(VI) sorption (i.e., sorption/reduction of Cr(VI) and simultaneous formation and binding of reduced Cr(III)) when formulating a model that describes the overall sorption process. On the other hand Cr(VI) scarcely exists alone in wastewaters, it is usually found in mixtures with divalent metals. Therefore, the simultaneous removal of Cr(VI) and divalent metals in binary mixtures and the interactive mechanism governing Cr(VI) elimination have gained more and more attention. In the present work, kinetics of Cr(VI) sorption onto exhausted coffee from Cr(VI)–Cu(II) binary mixtures has been studied in a stirred batch reactor. A model including Cr(VI) sorption and reduction, Cr(III) sorption and the effect of the presence of Cu(II) in these processes has been developed and validated. This study constitutes an important advance in modeling Cr(VI) sorption kinetics especially when chromium sorption is in part based on the sorbent capacity of reducing hexavalent chromium and a metal cation is present in the binary mixture. - Highlights: • A kinetic model including Cr(VI) reduction, Cr(VI) and Cr(III) sorption/desorption • Synergistic effect of Cu(II) on Cr(VI) elimination included in the model • Model validation by checking it against independent sets of data.

  14. Influence of the ionic liquid cation on the solvent extraction of trivalent rare-earth ions by mixtures of Cyanex 923 and ionic liquids.

    Science.gov (United States)

    Rout, Alok; Binnemans, Koen

    2015-01-21

    Trivalent rare-earth ions were extracted from nitric acid medium by the neutral phosphine oxide extractant Cyanex 923 into ionic liquid phases containing the bis(trifluoromethylsulfonyl)imide anion. Five different cations were considered: 1-butyl-3-methylimidazolium, 1-decyl-3-methylimidazolium, methyltributylammonium, methyltrioctylammonium and trihexyl(tetradecyl)phosphonium. The extraction behavior of neodymium(iii) was investigated as a function of various parameters: pH, extractant concentration, concentration of the neodymium(iii) ion in the aqueous feed and concentration of the salting-out agent. The loading capacity of the ionic liquid phase was studied. The extraction efficiency increased with increasing pH of the aqueous feed solution. The extraction occurred for all ionic liquids via an ion-exchange mechanism and the extraction efficiency could be related to the solubility of the ionic liquid cation in the aqueous phase: high distribution ratios for hydrophilic cations and low ones for hydrophobic cations. Addition of nitrate ions to the aqueous phase resulted in an increase in extraction efficiency for ionic liquids with hydrophobic cations due to extraction of neutral complexes. Neodymium(iii) could be stripped from the ionic liquid phase by 0.5-1.0 M nitric acid solutions and the extracting phase could be reused. The extractability of other rare earths present in the mixture was compared for the five ionic liquids.

  15. Thermodynamic properties of binary liquid mixtures of diethylenetriamine with alcohols at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Gyan Prakash, E-mail: gyan.dubey@rediffmail.com [Department of Chemistry, Kurukshetra University, Kurukshetra 136119 (India); Kumar, Krishan [Department of Chemistry, Kurukshetra University, Kurukshetra 136119 (India)

    2011-09-20

    Highlights: {yields} Thermodynamic study of diethylenetriamine + 2-methyl-1-propanol, +2-propanol or +1-butanol have been made. {yields} Excess molar volumes and isentropic compressibility were determined. {yields} Types of interactions were discussed based on derived properties. - Abstract: Densities, {rho}, viscosities, {eta}, and speeds of sound, u, were measured for the binary liquid mixtures containing diethylenetriamine with 2-methyl-1-propanol, 2-propanol and 1-butanol at 293.15, 298.15, 303.15, 308.15 and 313.15 K. From density and speed of sound data, excess molar volumes, V{sub m}{sup E} and deviations in isentropic compressibility, {Delta}{kappa}{sub s}, and speed of sound, {Delta}u have been evaluated. Viscosity data were used to compute deviations in viscosity and excess Gibbs energy of activation of viscous flow {Delta}G*{sup E} at 298.15, 303.15 and 308.15 K. A Redlich-Kister type equation was applied to fit the excess molar volumes and deviations in isentropic compressibility, speed of sound and viscosity data. The viscosity data have been correlated with the equations of Grunberg-Nissan, Tamura-Kurata, Heric-Brewer and of Hind et al. All the binary systems of the present study have negative values of excess molar volumes and deviations in isentropic compressibility over whole composition range and at all temperatures which indicates strong interactions between the components of binary mixtures.

  16. Benzoic Acid and Chlorobenzoic Acids: Thermodynamic Study of the Pure Compounds and Binary Mixtures With Water.

    Science.gov (United States)

    Reschke, Thomas; Zherikova, Kseniya V; Verevkin, Sergey P; Held, Christoph

    2016-03-01

    Benzoic acid is a model compound for drug substances in pharmaceutical research. Process design requires information about thermodynamic phase behavior of benzoic acid and its mixtures with water and organic solvents. This work addresses phase equilibria that determine stability and solubility. In this work, Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was used to model the phase behavior of aqueous and organic solutions containing benzoic acid and chlorobenzoic acids. Absolute vapor pressures of benzoic acid and 2-, 3-, and 4-chlorobenzoic acid from literature and from our own measurements were used to determine pure-component PC-SAFT parameters. Two binary interaction parameters between water and/or benzoic acid were used to model vapor-liquid and liquid-liquid equilibria of water and/or benzoic acid between 280 and 413 K. The PC-SAFT parameters and 1 binary interaction parameter were used to model aqueous solubility of the chlorobenzoic acids. Additionally, solubility of benzoic acid in organic solvents was predicted without using binary parameters. All results showed that pure-component parameters for benzoic acid and for the chlorobenzoic acids allowed for satisfying modeling phase equilibria. The modeling approach established in this work is a further step to screen solubility and to predict the whole phase region of mixtures containing pharmaceuticals.

  17. Nucleate Pool Boiling of Pure Liquids and Binary Mixtures:part II—Analytical Model for Boiling Heat Transfer of Binary Mixtures on Smooth Tubes and Comparison of Analytical Models for both Pure Liqu

    Institute of Scientific and Technical Information of China (English)

    GuoqingWang; YingkeTan

    1996-01-01

    A combined physical model of bubbel growth is propsed along with a corresponding bubble growth model for binary mixtures on smooth tubes.Using the general model of Wang et al.[1].and the bubble growth model for binary mixtures,an analytical model for nucleate pool boiling heat transfer of binary mixtures on smooth tubes is developed.In addition,nucleate pool boiling heat transfer of pure liquids and binary mixtrues on a horizontal smooth tube was studied experimentally.The pure liquids and binary mixtures included water methanol,ehanol,and their binary mixtures.The analytical models for both pure liquids and binary mixtures are in good agreement with the experimental data.

  18. Volumetric Behavior of Binary Mixtures of Alkoxyethanols and Some Selected Amines at 298.15 K

    Directory of Open Access Journals (Sweden)

    Ayasen Jermaine Kemeakegha

    2015-01-01

    Full Text Available Densities of binary mixtures of 2-methoxyethanol (2-MeO-EtOH and 2-ethoxyethanol (2-EtO-EtOH with hexylamine (HLA, diethylamine (DEA, triethylamine (TEA, tert-butylamine (TBA, aniline (ANL, and benzylamine (BLA have been determined at varying compositions of the alkoxyalkanols at 298.15 K. The excess molar volumes, VE, of the binary mixtures were calculated from the experimental density data of the mixtures and the component single solvents. The calculated excess molar volumes were fitted into the Redlich-Kister polynomial to obtain the fitting coefficients and standard deviations. The excess molar volumes of the binary mixtures of all the solvent systems investigated were negative over the entire range of the solvents composition. The negative values were attributed to stronger hydrogen bond formations between the unlike molecules of mixtures than those between the like molecules of the pure components. The magnitude of the excess molar volumes of the binary mixtures of 2-methoxyethanol and the aliphatic amines were in the order TBA > TEA > DEA > HEA. For the two aromatic amines, the magnitudes were in the order BLA > ANL. For binary mixtures of the amines and 2-ethoxyethanol, the magnitudes were in the order DEA > TEA > TBA > HEA at compositions where the mole fraction of 2-EtO-EtOH was ≤0.5 and TBA > TEA > DEA > HEA above 0.5 mole fraction of 2-EtO-EtOH.

  19. Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

    Directory of Open Access Journals (Sweden)

    Richard Bates

    2014-06-01

    Full Text Available We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8 coolant into nitrogen during a long duration (18 month continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions.

  20. Symmetrization of excess Gibbs free energy: A simple model for binary liquid mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos-Suarez, Aly J., E-mail: acastell@ivic.gob.v [Centro de Estudios Interdisciplinarios de la Fisica (CEIF), Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 21827, Caracas 1020A (Venezuela, Bolivarian Republic of); Garcia-Sucre, Maximo, E-mail: mgs@ivic.gob.v [Centro de Estudios Interdisciplinarios de la Fisica (CEIF), Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 21827, Caracas 1020A (Venezuela, Bolivarian Republic of)

    2011-03-15

    A symmetric expression for the excess Gibbs free energy of liquid binary mixtures is obtained using an appropriate definition for the effective contact fraction. We have identified a mechanism of local segregation as the main cause of the contact fraction variation with the concentration. Starting from this mechanism we develop a simple model for describing binary liquid mixtures. In this model two parameters appear: one adjustable, and the other parameter depending on the first one. Following this procedure we reproduce the experimental data of (liquid + vapor) equilibrium with a degree of accuracy comparable to well-known more elaborated models. The way in which we take into account the effective contacts between molecules allows identifying the compound which may be considered to induce one of the following processes: segregation, anti-segregation and dispersion of the components in the liquid mixture. Finally, the simplicity of the model allows one to obtain only one resulting interaction energy parameter, which makes easier the physical interpretation of the results.

  1. Gas suspension flows of a moderately dense binary mixture of solid particles in vertical tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zamankhan, P.; Huotari, J. [VTT Energy, Jyvaeskylae (Finland). Combustion and Conversion Lab.

    1996-12-01

    The turbulent, steady, fully-developed flow of a moderately dense (solid volume faction >>0.001) binary mixture of spherical particles in a gaseous carrier is investigated for the case of flow in a vertical riser. The suspended particles are considered to be in turbulent motion, driven by random aerodynamic forces acting between the particle and the gaseous carrier as well as particle-particle interactive forces. A model is constructed based on the combination of the time-averaged after volume-averaged conservation equations of mass, momentum and mechanical energy of the gas phase in the continuum theory and the corresponding equations for the solid particles obtained using the recently developed Enskog theory for dense multi-component mixtures of slightly inelastic spherical particles. The model properly takes into account the contributions of particle-particle collisions, as well as the fluid-dynamic fluctuating forces on individual particles. To demonstrate the validity of this approach, the fully-developed steady-state mean velocity and concentration distributions of a moderately dense binary mixture of solid particles in a turbulent vertical flow calculated by the present model are compared with available experimental measurements. The results provide a qualitative description of the experimentally observed motion of coarse particles in a fast bed of fine solids. (author)

  2. Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra

    Science.gov (United States)

    Lotfy, Hayam M.; Saleh, Sarah S.; Hassan, Nagiba Y.; Salem, Hesham

    2015-02-01

    This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt's method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

  3. Optimizing the surface density of polyethylene glycol chains by grafting from binary solvent mixtures

    Science.gov (United States)

    Arcot, Lokanathan; Ogaki, Ryosuke; Zhang, Shuai; Meyer, Rikke L.; Kingshott, Peter

    2015-06-01

    Polyethylene glycol (PEG) brushes are very effective at controlling non-specific deposition of biological material onto surfaces, which is of paramount importance to obtaining successful outcomes in biomaterials, tissue engineered scaffolds, biosensors, filtration membranes and drug delivery devices. We report on a simple 'grafting to' approach involving binary solvent mixtures that are chosen based on Hansen's solubility parameters to optimize the solubility of PEG thereby enabling control over the graft density. The PEG thiol-gold model system enabled a thorough characterization of PEG films formed, while studies on a PEG silane-silicon system examined the versatility to be applied to any substrate-head group system by choosing an appropriate solvent pair. The ability of PEG films to resist non-specific adsorption of proteins was quantitatively assessed by full serum exposure studies and the binary solvent strategy was found to produce PEG films with optimal graft density to efficiently resist protein adsorption.

  4. Effect of the Structure of Cations and Anions of Ionic Liquids on Separation of Aromatics from Hydrocarbon Mixtures

    Institute of Scientific and Technical Information of China (English)

    Liu Yansheng; Zhang Zhongxin; Zhang Guofu; Liu Zhichang; Hu Yufeng; Shi Quan; Ji Dejun

    2006-01-01

    The effects of the structure of typical cations and anions of ionic liquids on the separation of benzene and toluene from aromatic/paraffin mixtures were studied. The results showed that the corresponding separation factors were considerably larger than those of the traditional solvents (Benzene+Hexane+sulfolane), and that the ionic liquids could be used as novel solvents for the separation of aromatics from hydrocarbon mixtures. The key parameters governing the ability of ionic liquids for separating aromatics from hydrocarbon sources were investigated. It was found that the effectiveness of the ionic liquids, based on the same anion, changed in the cation order of [BIqu]+< [BPy]+< [BMIM]+. The selectivity of the ionic liquid toward aromatics decreased apparently with the increasing length of the substituted alkyl chain of its cationic head ring. The separation factors, based on the same cation, changed in the anion order of [Tf2N]-<[PF6]-<[BF4]-<[C2H5SO4]-. The solubilities of the aromatics were greater in the ionic liquids based on the former three anions than that in the ionic liquids involving [C2H5SO4]-.

  5. Thermodiffusion, molecular diffusion and Soret coefficients of aromatic+n-alkane binary mixtures

    Science.gov (United States)

    Larrañaga, Miren; Bou-Ali, M. Mounir; Lapeira, Estela; Lizarraga, Ion; Santamaría, Carlos

    2016-10-01

    In the present work, we have measured the thermodiffusion coefficient of 51 binary liquid mixtures at 25 oC. These mixtures correspond to the series of the aromatics toluene and 1-methylnaphthalene with n-alkanes nCi (i = 6, 8, 10, 12, and 14) at different mass fractions in the whole range. For that, we have used the thermogravitational technique. It is shown that the thermodiffusion coefficient is a linear function of the mass fraction in all the mixtures. Extrapolating the lines, we obtain the thermodiffusion coefficient in dilute solutions of n-alkanes for both toluene and 1-methylnaphthalene. These limiting values show a linear dependence with the inverse of the product of the molecular weights. In addition, we have measured the molecular diffusion coefficient of all the mixtures at 0.5 of mass fraction and at 25 oC, by the sliding symmetric tubes technique. It is observed that the product of this coefficient with the viscosity at the same concentrations takes a constant value for each of the series considered. Finally, we have also determined the Soret coefficient of the equimass mixtures by the combination of the measurements of thermodiffusion and molecular diffusion coefficients.

  6. Quantitative Characterization of the Toxicities of Cd-Ni and Cd-Cr Binary Mixtures Using Combination Index Method

    Directory of Open Access Journals (Sweden)

    Lingyun Mo

    2016-01-01

    Full Text Available Direct equipartition ray design was used to construct Cd-Ni and Cd-Cr binary mixtures. Microplate toxicity analysis was used to evaluate the toxicity of individual substance and the Cd-Ni and Cd-Cr mixtures on Chlorella pyrenoidosa and Selenastrum capricornutum. The interacting toxicity of the mixture was analyzed with concentration addition (CA model. In addition, combination index method (CI was proposed and used to quantitatively characterize the toxicity of the binary mixtures of Cd-Ni and Cd-Cr observed in experiment and find the degree of deviation from the predicted outcome of the CA model, that is, the intensity of interacting toxicity. Results indicate that most of the 20 binary mixtures exhibit enhancing and synergistic effect, and only Cd-Cr-R4 and Cd-Cr-R5 mixtures have relatively high antagonistic effects against C. pyrenoidosa. Based on confidence interval, CI can compare the intensities of interaction of the mixtures under varying levels of effect. The characterization methods are applicable for analyzing binary mixture with complex interaction.

  7. Picosecond solvation dynamics—A potential viewer of DMSO—Water binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Banik, Debasis; Kundu, Niloy; Kuchlyan, Jagannath; Roy, Arpita; Banerjee, Chiranjib; Ghosh, Surajit; Sarkar, Nilmoni, E-mail: nilmoni@chem.iitkgp.ernet.in [Department of Chemistry, Indian Institute of Technology, Kharagpur, WB 721302 (India)

    2015-02-07

    In this work, we have investigated the composition dependent anomalous behavior of dimethyl sulfoxide (DMSO)-water binary mixture by collecting the ultrafast solvent relaxation response around a well known solvation probe Coumarin 480 (C480) by using a femtosecond fluorescence up-conversion spectrometer. Recent molecular dynamics simulations have predicted two anomalous regions of DMSO-water binary mixture. Particularly, these studies encourage us to investigate the anomalies from experimental background. DMSO-water binary mixture has repeatedly given evidences of its dual anomalous nature in front of our systematic investigation through steady-state and time-resolved measurements. We have calculated average solvation times of C480 by two individual well-known methods, among them first one is spectral-reconstruction method and another one is single-wavelength measurement method. The results of both the methods roughly indicate that solvation time of C480 reaches maxima in the mole fraction of DMSO X{sub D} = 0.12–0.17 and X{sub D} = 0.27–0.35, respectively. Among them, the second region (X{sub D} = 0.27–0.35) is very common as most of the thermodynamic properties exhibit deviation in this range. Most probably, the anomalous solvation trend in this region is fully guided by the shear viscosity of the medium. However, the first region is the most interesting one. In this region due to formation of strongly hydrogen bonded 1DMSO:2H{sub 2}O complexes, hydration around the probe C480 decreases, as a result of which solvation time increases.

  8. Thermophysical properties of energetic ionic liquids/nitric acid mixtures: Insights from molecular dynamics simulationsa)

    Science.gov (United States)

    Hooper, Justin B.; Smith, Grant D.; Bedrov, Dmitry

    2013-09-01

    Molecular dynamics (MD) simulations of mixtures of the room temperature ionic liquids (ILs) 1-butyl-4-methyl imidazolium [BMIM]/dicyanoamide [DCA] and [BMIM][NO3-] with HNO3 have been performed utilizing the polarizable, quantum chemistry based APPLE&P® potential. Experimentally it has been observed that [BMIM][DCA] exhibits hypergolic behavior when mixed with HNO3 while [BMIM][NO3-] does not. The structural, thermodynamic, and transport properties of the IL/HNO3 mixtures have been determined from equilibrium MD simulations over the entire composition range (pure IL to pure HNO3) based on bulk simulations. Additional (non-equilibrium) simulations of the composition profile for IL/HNO3 interfaces as a function of time have been utilized to estimate the composition dependent mutual diffusion coefficients for the mixtures. The latter have been employed in continuum-level simulations in order to examine the nature (composition and width) of the IL/HNO3 interfaces on the millisecond time scale.

  9. Study of Molecular Interactions in Binary Liquid Mixtures by Acoustical Method at 303K

    Directory of Open Access Journals (Sweden)

    P. Paul Divakar

    2012-01-01

    Full Text Available Ultrasonic velocity and density measurements were made in two binary liquid mixtures Isopropyl acetate (IPA and Isobutyl acetate (IBA with cyclohexanone (CY as a common component at 303K, at fixed frequency of 2MHz using single crystal variable path interferometer and specific gravity bottle respectively. The experimental data have been used to calculate the acoustic impedance, adiabatic compressibility, inter molecular free length and molar volume. The excess thermodynamic parameters have been evaluated and discussed in the light of molecular interactions.

  10. Experimental and Predicted Viscosities of Binary Mixtures Containing Chlorinated and Oxygenated Compounds

    Science.gov (United States)

    Montaño, D.; Artigas, H.; Royo, F. M.; Lafuente, Carlos

    2013-01-01

    This study presents the viscosities, both kinematic and dynamic, of binary mixtures of 1-chlorobutane, 2-chlorobutane, or 1-chloro-2-methylpropane with butyl ethyl ether or methyl tert-butyl ether from T = 283.15 K to T = 313.15 K at atmospheric pressure as a function of composition. Kinematics viscosities were measured using an Ubbelohde viscometer. The dynamic viscosities were obtained from experimental kinematic viscosities and previously reported density data. The viscosity results have been employed to check the reliability of the Wu-UNIFAC method.

  11. Solid-state characterization of paracetamol metastable polymorphs formed in binary mixtures with hydroxypropylmethylcellulose

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Alessandra; Savioli, Alessandra; Bini, Marcella; Capsoni, Doretta; Massarotti, Vincenzo; Bettini, Ruggero; Gazzaniga, Andrea; Sangalli, Maria Edvige; Giordano, Ferdinando

    2003-11-28

    Two metastable polymorphs of paracetamol (forms II and III) were prepared by appropriate thermal methods from binary mixtures containing 10% (w/w) of hydroxypropylmethylcellulose. By controlling the reheating step, it was possible to address the recrystallization of the drug either into form II or III. Moreover, it was observed that form III transforms either into form II or I depending on the preparation method. The physical characterization of the polymorphs was performed by means of micro-Fourier transform infrared spectroscopy (MFTIR) and powder X-ray diffractometry (PXRD), both temperature controlled.

  12. 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.

  13. Thermo Physical Properties for Binary Mixture of Dimethylsulfoxide and Isopropylbenzene at Various Temperatures

    Directory of Open Access Journals (Sweden)

    Maninder Kumar

    2013-01-01

    Full Text Available Density, refractive index, speed of sound, and viscosity have been measured of binary mixture dimethylsulfoxide (DMSO + isopropylbenzene (CUMENE over the whole composition range at 298.15, 303.15, 308.15, and 313.15 K and atmospheric pressure. From these experimental measurements the excess molar volume, deviations in viscosity, molar refractivity, speed of sound, and isentropic compressibility have been calculated. These deviations have been correlated by a polynomial Redlich-Kister equation to derive the coefficients and standard error. The viscosities have furthermore been correlated with two or three parameter models, that is, herric correlation and McAllister model, respectively.

  14. Different spectrophotometric methods applied for the analysis of binary mixture of flucloxacillin and amoxicillin: A comparative study

    Science.gov (United States)

    Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

    2016-05-01

    Three different spectrophotometric methods were applied for the quantitative analysis of flucloxacillin and amoxicillin in their binary mixture, namely, ratio subtraction, absorbance subtraction and amplitude modulation. A comparative study was done listing the advantages and the disadvantages of each method. All the methods were validated according to the ICH guidelines and the obtained accuracy, precision and repeatability were found to be within the acceptable limits. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. So, they can be used for the routine analysis of flucloxacillin and amoxicillin in their binary mixtures.

  15. Wave convection regimes in a binary mixture in a modulated gravitational field

    Energy Technology Data Exchange (ETDEWEB)

    Myznikova, B. I. [Russian Academy of Sciences, Institute of Mechanics of Continuous Media, Ural Branch (Russian Federation); Smorodin, B. L., E-mail: bsmorodin@yandex.ru [Perm State University (Russian Federation)

    2011-03-15

    Nonlinear wave convection regimes are studied in a horizontal layer of an incompressible binary mixture with anomalous thermal diffusion in the gravitational field modulated with an arbitrary amplitude and finite frequency. Oscillation regimes are numerically simulated by the finite difference method for the case of a layer with impenetrable rigid boundaries, which better corresponds to experimental laboratory conditions. A qualitative difference is found in the dynamics of nonlinear quasi-periodic and subharmonic oscillations appearing in the initially stratified mixture and behaving as modulated and regular standing waves. The dependences of the intensity of convective flows on the modulation amplitude are obtained. The results of nonlinear calculations are compared with data on the boundaries of the equilibrium stability found from the linear theory. It is shown that a region of parameters exists where alternating action suppresses the convective motion.

  16. Thermodynamic study of binary mixtures containing 1-butylpyridinium tetrafluoroborate and methanol, or ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Mardones, M.; Perez-Gregorio, V.; Guerrero, H.; Bandres, I. [Departamento de Quimica Organica-Quimica Fisica, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza (Spain); Lafuente, C., E-mail: celadi@unizar.e [Departamento de Quimica Organica-Quimica Fisica, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza (Spain)

    2010-12-15

    Densities and speeds of sound have been determined for the binary mixture (1-butylpyridinium tetrafluoroborate + methanol, or ethanol) over the temperature range 293.15 K to 323.15 K. From experimental values, excess volume and excess isentropic compressibility have been calculated. The mixtures give negative values for the excess properties. Besides, (vapour + liquid) equilibrium in isothermal conditions has been obtained for these systems at T = 303.15 K and T = 323.15 K, which has allowed us to derive activity coefficients and excess Gibbs functions. Positive deviations from Raoult's law have been found. A detailed analysis and interpretation of results have been carried out in structural and energetic terms using thermodynamic information of the pure compounds.

  17. A smart simple spectrophotometric method for simultaneous determination of binary mixtures

    Institute of Scientific and Technical Information of China (English)

    Eman S. Elzanfaly; Ahmed S. Saad; Abd Elaziz B. Abd Elaleem

    2012-01-01

    A new simple spectrophotometric method was developed for the simultaneous determination of drugs with interfering spectra in binary mixtures without previous separation. The new method is based on a simple modification for the ratio subtraction method. This modification enabled wider range of application. The proposed ratio difference method was applied for the determination of brimonidine and timolol in laboratory prepared mixtures with mean percentage recoveries 100.40±2.29 and 101.23± 1.30 respectively, and in their pharmaceutical formulation with mean percentage recoveries 101.08±0.44 and 100.66±0.52 respectively. The suggested ratio difference method was validated according to USP guidelines and can be applied for routine aualitv control testing.

  18. Simultaneous spectrophotometric determination of amlodipine besylate and atorvastatin calcium in binary mixture

    Directory of Open Access Journals (Sweden)

    Sahu R

    2007-01-01

    Full Text Available A rapid, simple, accurate and precise UV Spectrophotometric method using simultaneous equation was developed for the simultaneous determination of amlodipine besylate and atorvastatin calcium in a binary mixture. In the proposed method, the signals were measured at 238.2 and 246.6 nm corresponding to the absorbance maxima of amlodipine besylate and atorvastatin calcium in methanol, respectively. Linearity was observed in the concentration range of 5-30 µg/ml for both the drugs. Concentration of each drug was obtained by using the absorptivity values calculated for both the drugs at two wavelengths, 238.2 and 246.6 nm and solving the simultaneous equations. The method was validated statistically and recovery study was performed to confirm the accuracy of the method. Laboratory prepared synthetic mixture was successfully analyzed using the developed method.

  19. Liquid-liquid interfacial properties of a symmetrical Lennard-Jones binary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Ruiz, F. J.; Blas, F. J., E-mail: felipe@uhu.es [Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Física Aplicada, Universidad de Huelva, 21007 Huelva (Spain); Moreno-Ventas Bravo, A. I. [Laboratorio de Simulación Molecular y Química Computacional, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Geología, Universidad de Huelva, 21007 Huelva (Spain)

    2015-09-14

    We determine the interfacial properties of a symmetrical binary mixture of equal-sized spherical Lennard-Jones molecules, σ{sub 11} = σ{sub 22}, with the same dispersive energy between like species, ϵ{sub 11} = ϵ{sub 22}, but different dispersive energies between unlike species low enough to induce phase separation. We use the extensions of the improved version of the inhomogeneous long-range corrections of Janecek [J. Phys. Chem. B 110, 6264 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] and Martínez-Ruiz et al. [J. Chem. Phys. 141, 184701 (2014)], to deal with the interaction energy and microscopic components of the pressure tensor. We perform Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of the symmetrical mixture with different cut-off distances r{sub c} and in combination with the inhomogeneous long-range corrections. The pressure tensor is obtained using the mechanical (virial) and thermodynamic route. The liquid-liquid interfacial tension is also evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the test-area methodology. This allows to check the validity of the recent extensions presented to deal with the contributions due to long-range corrections for intermolecular energy and pressure tensor in the case of binary mixtures that exhibit liquid-liquid immiscibility. In addition to the pressure tensor and the surface tension, we also obtain density profiles and coexistence densities and compositions as functions of pressure, at a given temperature. According to our results, the main effect of increasing the cut-off distance r{sub c} is to sharpen the liquid-liquid interface and to increase the width of the biphasic coexistence region. Particularly interesting is the presence of a relative minimum in the total density profiles of the symmetrical mixture. This minimum is related

  20. Monte Carlo neutral particle transport through a binary stochastic mixture using chord length sampling

    Science.gov (United States)

    Donovan, Timothy J.

    A Monte Carlo algorithm is developed to estimate the ensemble-averaged behavior of neutral particles within a binary stochastic mixture. A special case stochastic mixture is examined, in which non-overlapping spheres of constant radius are uniformly mixed in a matrix material. Spheres are chosen to represent the stochastic volumes due to their geometric simplicity and because spheres are a common approximation to a large number of applications. The boundaries of the mixture are impenetrable, meaning that spheres in the stochastic mixture cannot be assumed to overlap the mixture boundaries. The algorithm employs a method called Limited Chord Length Sampling (LCLS). While in the matrix material, LCLS uses chord-length sampling to sample the distance to the next stochastic interface. After a surface crossing into a stochastic sphere, transport is treated explicitly until the particle exits or is killed. This capability eliminates the need to explicitly model a representation of the random geometry of the mixture. The algorithm is first proposed and tested against benchmark results for a two dimensional, fixed source model using stand-alone Monte Carlo codes. The algorithm is then implemented and tested in a test version of the Los Alamos M&barbelow;onte C&barbelow;arlo ṉ-p&barbelow;article Code MCNP. This prototype MCNP version has the capability to calculate LCLS results for both fixed source and multiplied source (i.e., eigenvalue) problems. Problems analyzed with MCNP range from simple binary mixtures, designed to test LCLS over a range of optical thicknesses, to a detailed High Temperature Gas Reactor fuel element, which tests the value of LCLS in a current problem of practical significance. Comparisons of LCLS and benchmark results include both accuracy and efficiency comparisons. To ensure conservative efficiency comparisons, the statistical basis for the benchmark technique is derived and a formal method for optimizing the benchmark calculations is developed

  1. Stationary and transient Soret separation in a binary mixture with a consolute critical point.

    Science.gov (United States)

    Ryzhkov, Ilya I; Kozlova, Sofia V

    2016-12-01

    The stationary and transient Soret separation in a binary mixture with a consolute critical point is studied theoretically. The mixture is placed between two parallel plates kept at different temperatures. A polymer blend is used as a model system. Analytical solutions are constructed to describe the stationary separation in a binary mixture with variable Soret coefficient. The latter strongly depends on temperature and concentration and enhances near a consolute critical point due to reduced diffusion. As a result, a large concentration gradient is observed locally, while much smaller concentration variations are found in the rest of the layer. It is shown that complete separation can be obtained by applying a small temperature difference first, waiting for the establishment of stationary state, and then increasing this difference again. In this case, the critical temperature lies between hot and cold wall temperatures, while the mixture still remains in the one-phase region. When the initial (mean) temperature or concentration are shifted away from the near-critical values, the separation decreases. The analysis of transient behavior shows that the Soret separation occurs much faster than diffusion to the homogeneous state when the initial concentration is close to the critical one. It happens due to the decrease (increase) of the local relaxation time during the Soret (Diffusion) steps. The transient times of these steps become comparable for small temperature differences or off-critical initial concentrations. An unusual (non-exponential) separation dynamics is observed when the separation starts in the off-critical domain, and then enhances greatly when the system enters into the near-critical region. It is also found that the transient time decreases with increasing the applied temperature difference.

  2. Phase diagram, solubility limit and hydrodynamic properties of cellulose in binary solvents with ionic liquid.

    Science.gov (United States)

    Le, Kim Anh; Rudaz, Cyrielle; Budtova, Tatiana

    2014-05-25

    Cellulose solubility phase diagrams in two binary solvents based on 1-ethyl-3-methylimidazolium acetate (EmimAc) mixed with water and with dimethylsulfoxide (DMSO) were built. The minimal amount of EmimAc molecules needed to dissolve cellulose is 2.5-3moles per anhydroglucose unit. This proportion allows calculation of the maximal cellulose concentration soluble in EmimAc-DMSO at any composition; in EmimAc it is around 25-27wt%. Water forms hydrogen bonds with EmimAc and thus competes with cellulose for ionic liquid; the solubility of cellulose in EmimAc-water is much lower than that in EmimAc-DMSO. Hydrodynamic properties of cellulose in two solvent systems were compared. In EmimAc-DMSO cellulose intrinsic viscosity practically does not depend on DMSO content as predicted by the phase diagram. The intrinsic viscosity in EmimAc-water first increases with water content due to cellulose self-aggregation and then abruptly decreases due to coagulation.

  3. PHASE EQUILIBRIA FOR BINARY SYSTEMS CONTAINING IONIC LIQUID WITH WATER OR HYDROCARBONS

    Directory of Open Access Journals (Sweden)

    Dheiver Santos

    2015-12-01

    Full Text Available Abstract In this work, the mutual solubilities of sets of ionic liquids ([CnMIM] [TF2N] (n = 4, 8, 12, [C4PY] [TF2N], [C8MIM] [OTF] and organic compounds (heptane, o-xylene, toluene, or water are investigated. The experimental data measured for these systems were used to adjust the binary interaction parameters between their components for the Non-Random Two Liquid (NRTL model. The results showed that the solubility increased with temperature, with high hygroscopicity (10-1 in terms of mole fraction of the ILs, low interactions with aliphatic hydrocarbons, high interactions with aromatic hydrocarbons and the presence of a lower critical solution temperature (LCST. In addition, this study is the first to show that [C12MIM] [TF2N] is completely soluble in toluene and ortho-xylene between 273.15 and 373.15 K at 1 bar. The average deviations related to the mole fraction between the experimental and calculated values by the NRTL were less than 2.4%.

  4. Spectroscopic and DFT study of solvent effects on the electronic absorption spectra of sulfamethoxazole in neat and binary solvent mixtures.

    Science.gov (United States)

    Almandoz, M C; Sancho, M I; Blanco, S E

    2014-01-24

    The solvatochromic behavior of sulfamethoxazole (SMX) was investigated using UV-vis spectroscopy and DFT methods in neat and binary solvent mixtures. The spectral shifts of this solute were correlated with the Kamlet and Taft parameters (α, β and π(*)). Multiple lineal regression analysis indicates that both specific hydrogen-bond interaction and non specific dipolar interaction play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra using TD-DFT methods were in good agreement with the experimental ones. Binary mixtures consist of cyclohexane (Cy)-ethanol (EtOH), acetonitrile (ACN)-dimethylsulfoxide (DMSO), ACN-dimethylformamide (DMF), and aqueous mixtures containing as co-solvents DMSO, ACN, EtOH and MeOH. Index of preferential solvation was calculated as a function of solvent composition and non-ideal characteristics are observed in all binary mixtures. In ACN-DMSO and ACN-DMF mixtures, the results show that the solvents with higher polarity and hydrogen bond donor ability interact preferentially with the solute. In binary mixtures containing water, the SMX molecules are solvated by the organic co-solvent (DMSO or EtOH) over the whole composition range. Synergistic effect is observed in the case of ACN-H2O and MeOH-H2O, indicating that at certain concentrations solvents interact to form association complexes, which should be more polar than the individual solvents of the mixture.

  5. Interactions of Aqueous Imidazolium-Based Ionic Liquid Mixtures with Solid-Supported Phospholipid Vesicles

    Science.gov (United States)

    Losada-Pérez, Patricia; Khorshid, Mehran; Renner, Frank Uwe

    2016-01-01

    Despite the environmentally friendly reputation of ionic liquids (ILs), their safety has been recently questioned given their potential as cytotoxic agents. The fundamental mechanisms underlying the interactions between ILs and cells are less studied and by far not completely understood. Biomimetic films are here important biophysical model systems to elucidate fundamental aspects and mechanisms relevant for a large range of biological interaction ranging from signaling to drug reception or toxicity. Here we use dissipative quartz crystal microbalance QCM-D to examine the effect of aqueous imidazolium-based ionic liquid mixtures on solid-supported biomimetic membranes. Specifically, we assess in real time the effect of the cation chain length and the anion nature on a supported vesicle layer of the model phospholipid DMPC. Results indicate that interactions are mainly driven by the hydrophobic components of the IL, which significantly distort the layer and promote vesicle rupture. Our analyses evidence the gradual decrease of the main phase transition temperature upon increasing IL concentration, reflecting increased disorder by weakening of lipid chain interactions. The degree of rupture is significant for ILs with long hydrophobic cation chains and large hydrophobic anions whose behavior is reminiscent of that of antimicrobial peptides. PMID:27684947

  6. A multiscale transport model for binary Lennard Jones mixtures in slit nanopores

    Science.gov (United States)

    Bhadauria, Ravi; Aluru, N. R.

    2016-11-01

    We present a quasi-continuum multiscale hydrodynamic transport model for one dimensional isothermal, non-reacting binary mixture confined in slit shaped nanochannels. We focus on species transport equation that includes the viscous dissipation and interspecies diffusion term of the Maxwell-Stefan form. Partial viscosity variation is modeled by van der Waals one fluid approximation and the Local Average Density Method. We use friction boundary conditions where the wall-species friction parameter is computed using a novel species specific Generalized Langevin Equation model. The transport model accuracy is tested by predicting the velocity profiles of Lennard-Jones (LJ) methane-hydrogen and LJ methane-argon mixtures in graphene slit channels of different width. The resultant slip length from the continuum model is found to be invariant of channel width for a fixed mixture molar concentration. The mixtures considered are observed to behave as single species pseudo fluid, with the friction parameter displaying a linear dependence on the molar composition. The proposed model yields atomistic level accuracy with continuum scale efficiency.

  7. Gauge-invariant approach to thermodiffusion in a liquid binary mixture

    Science.gov (United States)

    Bringuier, E.

    2011-06-01

    The paper aims at a molecular understanding of thermodiffusion (the Ludwig-Soret effect) in a liquid binary mixture. To this end, we first review the capabilities of the Maxwell-Stefan description of interdiffusion, which in a liquid rests upon the use of a thermodynamic force. The latter is defined here as a force per particle which generalizes the mechanical force and obeys Newton's third law. Moreover, the force is required to be invariant under changes of the energy and entropy gauges. The gauge-invariant force thus defined is found to account for ordinary diffusion and barodiffusion, but not for thermodiffusion. The force driving thermodiffusion arises from Onsager's reciprocity theorem in non-equilibrium thermodynamics: it is shown to be proportional to the covariance of enthalpy and velocity. In case that intermolecular collisions are elastic, an explicit kinetic expression is given of the force driving thermodiffusion; it involves the interaction cross-section of the two components and the mean-free-path function of the liquid mixture. That expression is equivalent to, but much simpler than, the Chapman-Enskog result in gaseous mixtures, and it qualitatively accounts for observations performed in liquid mixtures. The role of the internal degrees of freedom of the molecules is brought out. Finally, two pragmatic rules for devising models of thermodiffusion are enunciated.

  8. Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

    Science.gov (United States)

    Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

    Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

  9. An experimental study of adsorption interference in binary mixtures flowing through activated carbon

    Science.gov (United States)

    Madey, R.; Photinos, P. J.

    1983-01-01

    The isothermal transmission through activated carbon adsorber beds at 25 C of acetaldehyde-propane and acetylene-ethane mixtures in a helium carrier gas was measured. The inlet concentration of each component was in the range between 10 ppm and 500 ppm. The constant inlet volumetric flow rate was controlled at 200 cc (STP)/min in the acetaldehyde-propane experiments and at 50 cc (STP)/min in the acetaldehyde-ethane experiments. Comparison of experimental results with the corresponding single-component experiments under similar conditions reveals interference phenomena between the components of the mixtures as evidenced by changes in both the adsorption capacity and the dispersion number. Propane was found to displace acetaldehyde from the adsorbed state. The outlet concentration profiles of propane in the binary mixtures tend to become more diffuse than the corresponding concentration profiles of the one-component experiments. Similar features were observed with mixtures of acetylene and ethane; however, the displacement of acetylene by ethane is less pronounced.

  10. Discriminative Stimulus Effects of Binary Drug Mixtures: Studies with Cocaine, MDPV, and Caffeine

    Science.gov (United States)

    Abbott, Megan; Galindo, Kayla; Rush, Elise L.; Rice, Kenner C.; France, Charles P.

    2016-01-01

    Illicit drug preparations often include more than one pharmacologically active compound. For example, cocaine and synthetic cathinones [e.g., 3,4-methylenedioxypyrovalerone (MDPV)] are often mixed with caffeine before sale. Caffeine is likely added to these preparations because it is inexpensive and legal; however, caffeine might also mimic or enhance some of the effects of cocaine or MDPV. In these studies, male Sprague-Dawley rats were trained to discriminate 10 mg/kg cocaine from saline, and the discriminative stimulus effects of cocaine, caffeine, and MDPV were evaluated alone and as binary mixtures (cocaine and caffeine, MDPV and caffeine, and cocaine and MDPV) at fixed-dose ratios of 3:1, 1:1, and 1:3 relative to the dose of each drug that produced 50% cocaine-appropriate responding. Dose-addition analyses were used to determine the nature of the drug-drug interactions for each mixture (e.g., additive, supra-additive, or subadditive). Although additive interactions were observed for most mixtures, supra-additive interactions were observed at the 50% effect level for the 1:1 mixture of cocaine and caffeine and at the 80% effect level for all three mixtures of cocaine and caffeine, as well as for the 3:1 and 1:3 mixtures of cocaine and MDPV. These results demonstrate that with respect to cocaine-like discriminative stimulus effects, caffeine can function as a substitute in drug preparations containing either cocaine or MDPV, with enhancements of cocaine-like effects possible under certain conditions. Further research is needed to determine whether similar interactions exist for other abuse-related or toxic effects of drug preparations, including cocaine, synthetic cathinones, and caffeine. PMID:27493274

  11. MD simulations of the formation of stable clusters in mixtures of alkaline salts and imidazolium-based ionic liquids.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; Bouzón-Capelo, Silvia; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

    2013-03-21

    Structural and dynamical properties of room-temperature ionic liquids containing the cation 1-butyl-3-methylimidazolium ([BMIM](+)) and three different anions (hexafluorophosphate, [PF6](-), tetrafluoroborate, [BF4](-), and bis(trifluoromethylsulfonyl)imide, [NTf2](-)) doped with several molar fractions of lithium salts with a common anion at 298.15 K and 1 atm were investigated by means of molecular dynamics simulations. The effect of the size of the salt cation was also analyzed by comparing these results with those for mixtures of [BMIM][PF6] with NaPF6. Lithium/sodium solvation and ionic mobilities were analyzed via the study of radial distribution functions, coordination numbers, cage autocorrelation functions, mean-square displacements (including the analysis of both ballistic and diffusive regimes), self-diffusion coefficients of all the ionic species, velocity and current autocorrelation functions, and ionic conductivity in all the ionic liquid/salt systems. We found that lithium and sodium cations are strongly coordinated in two different positions with the anion present in the mixture. Moreover, [Li](+) and [Na](+) cations were found to form bonded-like, long-lived aggregates with the anions in their first solvation shell, which act as very stable kinetic entities within which a marked rattling motion of salt ions takes place. With very long MD simulation runs, this phenomenon is proved to be on the basis of the decrease of self-diffusion coefficients and ionic conductivities previously reported in experimental and computational results.

  12. A law of mixtures for transport properties in binary particulate composites

    Science.gov (United States)

    Duncan, K. L.; Lodenquai, J. F.; Wagh, A. S.; Goretta, K. C.

    1998-09-01

    A connected-grain model was developed earlier to explain mechanical and thermal properties of porous ceramics and sedimentary rocks. We have now generalized this model for binary particulate composites, based on simulation of a connected-grain structure of individual components of the composites by randomly selecting individual grains and shrinking them. Repetition of this procedure results in a structure of a binary particulate composite that contains channels of individual components, through which transport occurs. We developed a generalized law of mixtures in which transport properties are expressed as scaling relationships that depend on the shrinking parameter expressed as an exponent. This parameter provides the skewness of the distribution of the grains. The model is compared with various transport properties of binary composites reported in the literature. In addition, the model is tested on YBa2Cu3Ox superconductors and Ag composites that were fabricated in our laboratory and tested for electrical conductivity and elastic modulus. This test demonstrates how the model predicts two entirely different transport properties through their common microstructure and grain-size distribution.

  13. Dielectric Behaviour of Binary Mixture of 2-Chloroaniline with 2-Methoxyethanol and 2-Ethoxyethanol

    Directory of Open Access Journals (Sweden)

    Bhupesh G. Nemmaniwar

    2013-05-01

    Full Text Available Densities, viscosities, refractive indices, dielectric constant (ε' and dielectric loss (ε'' of 2-chloroaniline (2CA + 2-methoxyethanol (2ME and 2-chloroaniline (2CA + 2-ethoxyethanol (2EE for different mole fractions of 2-chloroaniline in binary mixture have been measured at single microwave frequency 10.985 GHz at 300C by Surber method using microwave X-band. The values of dielectric parameters (ε' and ε''   have been used to evaluate the molar polarization (P12 loss tangent (tanδ, viscosity (η, activation energy (Ea, excess permittivity (Δε', excess dielectric loss (Δε'', excess viscosities (Δη, excess polarization (ΔP12 and excess activation energy (ΔEa  have also been estimated. These parameters have been used to explain the formation of complexes in the system. It is found that dielectric constant (ε', dielectric loss (ε'', loss tangent (tanδ, molar polarization (P12 varies non-linearly but activation energy (Ea , viscosity (η ,density (ρ, and refractive index (n varies linearly with increasing mole fraction in binary mixture of 2-chloroaniline (2-CA + 2-methoxyethanol (2-ME and 2-chloroaniline (2-CA + 2-ethoxyethanol (2-EE. Hence, solute-solvent molecular associations have been reported. 

  14. Quantum cluster equilibrium model of N-methylformamide–water binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Domaros, Michael von; Kirchner, Barbara, E-mail: kirchner@thch.uni-bonn.de [Mulliken Center for Theoretical Chemistry, Universität Bonn, Beringstr. 4, D-53115 Bonn (Germany); Jähnigen, Sascha [Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Germany); Friedrich, Joachim [Technische Universität Chemnitz, Straße der Nationen 62, D-09111 Chemnitz (Germany)

    2016-02-14

    The established quantum cluster equilibrium (QCE) approach is refined and applied to N-methylformamide (NMF) and its aqueous solution. The QCE method is split into two iterative cycles: one which converges to the liquid phase solution of the QCE equations and another which yields the gas phase. By comparing Gibbs energies, the thermodynamically stable phase at a given temperature and pressure is then chosen. The new methodology avoids metastable solutions and allows a different treatment of the mean-field interactions within the gas and liquid phases. These changes are of crucial importance for the treatment of binary mixtures. For the first time in a QCE study, the cis-trans-isomerism of a species (NMF) is explicitly considered. Cluster geometries and frequencies are calculated using density functional theory (DFT) and complementary coupled cluster single point energies are used to benchmark the DFT results. Independent of the selected quantum-chemical method, a large set of clusters is required for an accurate thermodynamic description of the binary mixture. The liquid phase of neat NMF is found to be dominated by the cyclic trans-NMF pentamer, which can be interpreted as a linear trimer that is stabilized by explicit solvation of two further NMF molecules. This cluster reflects the known hydrogen bond network preferences of neat NMF.

  15. Simulation of Binary CO2/CH4 Mixture Breakthrough Profiles in MIL-53 (Al

    Directory of Open Access Journals (Sweden)

    Luis Fernando Gomez

    2015-01-01

    Full Text Available MIL-53 (Al aluminum terephthalate, a commercial metal-organic framework, has been studied as a potential candidate for pressure swing adsorption separation of CO2/CH4 binary mixtures. Pure gas isotherms of CH4 and CO2 measured over 0–6 MPa and at room temperature are fitted with the Dubinin-Astakhov (D-A model. The D-A model parameters are used in the Doong-Yang Multicomponent adsorption model to predict the binary mixture isotherms. A one-dimensional multicomponent adsorption breakthrough model is then used to perform a parametric study of the effect of adsorbent particle diameter, inlet pressures, feed flow rates, and feed compositions on the breakthrough performance. Commercial MIL-53 with a particle diameter of 20 μm renders high tortuous flow; therefore it is less effective for separation. More effective separation can be achieved if MIL-53 monoliths of diameters above 200 μm are used. Faster separation is possible by increasing the feed pressure or if the starting compositions are richer in CO2. More CH4 is produced per cycle at higher feed pressures, but the shortened time at higher pressures can result in the reduction of the CH4 purity.

  16. Heat capacity singularity of binary liquid mixtures at the liquid-liquid critical point.

    Science.gov (United States)

    Méndez-Castro, Pablo; Troncoso, Jacobo; Peleteiro, José; Romaní, Luis

    2013-10-01

    The critical anomaly of the isobaric molar heat capacity for the liquid-liquid phase transition in binary nonionic mixtures is explained through a theory based on the general assumption that their partition function can be exactly mapped into that of the Ising three-dimensional model. Under this approximation, it is found that the heat capacity singularity is directly linked to molar excess enthalpy. In order to check this prediction and complete the available data for such systems, isobaric molar heat capacity and molar excess enthalpy near the liquid-liquid critical point were experimentally determined for a large set of binary liquid mixtures. Agreement between theory and experimental results-both from literature and from present work-is good for most cases. This fact opens a way for explaining and predicting the heat capacity divergence at the liquid-liquid critical point through basically the same microscopic arguments as for molar excess enthalpy, widely used in the frame of solution thermodynamics.

  17. PHARMACOKINETIC AND PHARMACODYNAMIC INTERACTION FOR A BINARY MIXTURE OF CHLORPYRIFOS AND DIAZINON IN THE RAT

    Energy Technology Data Exchange (ETDEWEB)

    Timchalk, Chuck; Poet, Torka S.; Hinman, Melissa N.; Busby, Andrea L.; Kousba, Ahmed A.

    2005-05-15

    Chlorpyrifos (CPF) and diazinon (DZN) are two commonly used organophosphorus (OP) insecticides and potential exists for concurrent exposures. The primary neurotoxic effects from OP pesticide exposures result from the inhibition of acetylcholinesterase (AChE) by their oxon metabolites. The pharmacokinetic and pharmacodynamic impact of acute binary exposures to CPF and DZN in rats were evaluated in this study. Rats were orally administered CPF, DZN or a CPF/DZN mixture (0, 15, 30 or 60 mg/kg) and blood (plasma and RBC), and brain were collected at 0, 3, 6, 12 and 24 h post-dosing, urine was also collected at 24 h. Chlorpyrifos, DZN and their respective metabolites 3,5,6-trichloro-2-pyridinol (TCP) and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMHP) were quantified in blood and/or urine and cholinesterase (ChE) inhibition was measured in brain, RBCs and plasma. Co-exposure to CPF/DZN at 15/15 mg/kg, did not appreciably alter the pharmacokinetics of CPF, DZN or their metabolites in blood; whereas, a 60/60 mg/kg dose resulted in a transient increase in Cmax, AUC, and decreased clearance of both compounds, likely due to competition between CPF and DZN for CYP450 metabolism. At lower doses, most likely to be encountered in occupational or environmental exposures, the pharmacokinetics were linear. A dose-dependent inhibition of ChE was noted in tissues for both the single and co-exposures. The overall potency for ChE inhibition was greater for CPF than DZN and the binary mixture response appeared to be strongly influenced by CPF. A comparison of the ChE binary response at the low dose (15 mg/kg), where there were no apparent pharmacokinetic interactions, suggested that the overall ChE response was additive. These are the first reported experiments we are aware of that characterize both the pharmacokinetic and pharmacodynamic interactions between CPF and DZN in the rat, and will be used to further develop a binary physiologically based pharmacokinetic and pharmacodynamic

  18. Continuous Wavelet Transform, a powerful alternative to Derivative Spectrophotometry in analysis of binary and ternary mixtures: A comparative study.

    Science.gov (United States)

    Elzanfaly, Eman S; Hassan, Said A; Salem, Maissa Y; El-Zeany, Badr A

    2015-12-05

    A comparative study was established between two signal processing techniques showing the theoretical algorithm for each method and making a comparison between them to indicate the advantages and limitations. The methods under study are Numerical Differentiation (ND) and Continuous Wavelet Transform (CWT). These methods were studied as spectrophotometric resolution tools for simultaneous analysis of binary and ternary mixtures. To present the comparison, the two methods were applied for the resolution of Bisoprolol (BIS) and Hydrochlorothiazide (HCT) in their binary mixture and for the analysis of Amlodipine (AML), Aliskiren (ALI) and Hydrochlorothiazide (HCT) as an example for ternary mixtures. By comparing the results in laboratory prepared mixtures, it was proven that CWT technique is more efficient and advantageous in analysis of mixtures with severe overlapped spectra than ND. The CWT was applied for quantitative determination of the drugs in their pharmaceutical formulations and validated according to the ICH guidelines where accuracy, precision, repeatability and robustness were found to be within the acceptable limit.

  19. Binding of Solvent Molecules to a Protein Surface in Binary Mixtures Follows a Competitive Langmuir Model.

    Science.gov (United States)

    Kulschewski, Tobias; Pleiss, Jürgen

    2016-09-06

    The binding of solvent molecules to a protein surface was modeled by molecular dynamics simulations of of Candida antarctica (C. antarctica) lipase B in binary mixtures of water, methanol, and toluene. Two models were analyzed: a competitive Langmuir model which assumes identical solvent binding sites with a different affinity toward water (KWat), methanol (KMet), and toluene (KTol) and a competitive Langmuir model with an additional interaction between free water and already bound water (KWatWat). The numbers of protein-bound molecules of both components of a binary mixture were determined for different compositions as a function of their thermodynamic activities in the bulk phase, and the binding constants were simultaneously fitted to the six binding curves (two components of three different mixtures). For both Langmuir models, the values of KWat, KMet, and KTol were highly correlated. The highest binding affinity was found for methanol, which was almost 4-fold higher than the binding affinities of water and toluene (KMet ≫ KWat ≈ KTol). Binding of water was dominated by the water-water interaction (KWatWat). Even for the three protein surface patches of highest water affinity, the binding affinity of methanol was 2-fold higher than water and 8-fold higher than toluene (KMet > KWat > KTol). The Langmuir model provides insights into the protein destabilizing mechanism of methanol which has a high binding affinity toward the protein surface. Thus, destabilizing solvents compete with intraprotein interactions and disrupt the tertiary structure. In contrast, benign solvents such as water or toluene have a low affinity toward the protein surface. Water is a special solvent: only few water molecules bind directly to the protein; most water molecules bind to already bound water molecules thus forming water patches. A quantitative mechanistic model of protein-solvent interactions that includes competition and miscibility of the components contributes a robust basis

  20. Solubilization of pentanol by cationic surfactants and binary mixtures of cationic surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, M.E.

    1993-12-31

    The research reported here has included studies of the solubilization of pentanol in hexadecylpyridinium chloride (CPC), trimethyletetradecylammonium chloride (C{sub 14}Cl), benzyldimethyltetradecylammonium chloride (C{sub 14}BzCl), benzyldimethylhexadecylpyridinium chloride (C{sub 16}BzCl), hexadecyltrimethylammonium bromide (CTAB), and binary mixtures of CPC + C{sub 16}BzCl and C{sub 14}Cl + C{sub 14}BzCl. Rather than using calorimetric methods, this project will employ headspace chromatography to measure solubilization of pentanol over a wide range of solute concentrations. While not yielding as much thermodynamic data as calorimetry, headspace chromatography is a more direct measure of the extent of solubilization. Using headspace chromatography, is a more direct measure of the extent of solubilization. Using headspace chromatography, this study will seek to determine whether strongly synergistic mixture ratios exist in the case of binary cationic surfactant systems. There are two equilibria in the pentanol-water-surfactant system: (1) The pentanol solubilized in micelles is in equilibrium with the monomeric pentanol in solution, and (2) the monomeric pentanol is in equilibrium with the pentanol in the vapor above the solution. To establish the link between the two equilibria, a sample of the vapor above pure liquid pentanol must be collected, in order to find the activity of pentanol in solution. Also, a calibration curve for various concentrations of pentanol in solution. From this type of data it is possible to infer both the concentration of pentanol solubilized in micelles and the concentrations of pentanol in the ``bulk`` solution outside the micelles. The method is equally applicable to systems containing a single surfactant as well as mixtures of surfactants.

  1. CONSOLIDATION AND COMPACTION OF POWDER MIXTURES .1. BINARY-MIXTURES OF SAME PARTICLE-SIZE FRACTIONS OF DIFFERENT TYPES OF CRYSTALLINE LACTOSE

    NARCIS (Netherlands)

    RIEPMA, KA; LERK, CF; DEBOER, AH; BOLHUIS, GK; KUSSENDRAGER, KD

    1990-01-01

    Binary powder mixtures of four different types of crystalline lactose: alpha-lactose monohydrate, anhydrous alpha-lactose, roller-dried beta-lactose and crystalline beta-lactose, were compressed into tablets. The results showed a proportional intercorrelation of the crushing strength and internal sp

  2. ANALYSIS OF THE KINETICS OF SOLVOLYSIS OF P-NITROPHENYLSULFONYLMETHYL PERCHLORATE IN BINARY ALCOHOLIC MIXTURES IN TERMS OF THE THERMODYNAMIC PROPERTIES OF THE SOLVENT MIXTURES

    NARCIS (Netherlands)

    WIJNEN, JW; ENGBERTS, JBFN; BLANDAMER, MJ

    1993-01-01

    Rate constants are reported for the solvolysis of p-nitrophenylsulfonylmethyl perchlorate in binary ethanolic and methanolic mixtures at 298.2 K. Co-solvents include hydrocarbons, chlorinated hydrocarbons and 1,4-dioxane. The kinetic data are examined in terms of the effect of decreasing mole fracti

  3. Multiscale Modeling of the effect of Pressure on the Interfacial Tension and other Cohesion Parameters in Binary Mixtures

    CERN Document Server

    Mayoral, E

    2016-01-01

    We study and predict the interfacial tension, solubility parameters and Flory-Huggins parameters of binary mixtures as functions of pressure and temperature, using multiscale numerical simulation. A mesoscopic approach is proposed for simulating the pressure dependence of the interfacial tension for binary mixtures, at different temperatures, using classical Dissipative Particle Dynamics (DPD). The thermodynamic properties of real systems are reproduced via the parametrization of the repulsive interaction parameters as functions of pressure and temperature via Molecular Dynamics simulations. Using this methodology, we calculate and analyze the cohesive density energy and the solubility parameters of different species obtaining excellent agreement with reported experimental behavior. The pressure- and temperature-dependent Flory-Huggins and repulsive DPD interaction parameters for binary mixtures are also obtained and validated against experimental data. This multiscale methodology offers the benefit of being ...

  4. Multiscale Modeling of the Effect of Pressure on the Interfacial Tension and Other Cohesion Parameters in Binary Mixtures.

    Science.gov (United States)

    Mayoral, E; Nahmad-Achar, E

    2016-03-10

    We study and predict the interfacial tension, solubility parameters, and Flory-Huggins parameters of binary mixtures as functions of pressure and temperature, using multiscale numerical simulation. A mesoscopic approach is proposed for simulating the pressure dependence of the interfacial tension for binary mixtures, at different temperatures, using classical dissipative particle dynamics (DPD). The thermodynamic properties of real systems are reproduced via the parametrization of the repulsive interaction parameters as functions of pressure and temperature via molecular dynamics simulations. Using this methodology, we calculate and analyze the cohesive energy density and the solubility parameters of different species obtaining excellent agreement with reported experimental behavior. The pressure- and temperature-dependent Flory-Huggins and repulsive DPD interaction parameters for binary mixtures are also obtained and validated against experimental data. This multiscale methodology offers the benefit of being applicable for any species and under difficult or nonfeasible experimental conditions, at a relatively low computational cost.

  5. Thermodynamic study of copper sulphate and zinc sulphate in water and binary aqueous mixtures of propylene glycol

    Directory of Open Access Journals (Sweden)

    R. C. Thakur

    2015-03-01

    Full Text Available Partial molar volumes of copper sulphate and zinc sulphate have been determined in water and binary aqueous mixtures of propylene glycol (2,4,6 and 8% by weight of propylene glycol at 303.15 K with the help of density measurements. Effect of temperature on the partial molar volumes was also analysed for these salts in water and binary aqueous mixtures of propylene glycol. Results obtained have been analysed by Masson’s equation and the experimental values of slopes and partial molar volumes of these transition metals sulphates have been interpreted in terms of ion-ion or ion –solvent interactions. Limiting molar expansibilities ( have also been determined which is interpreted in terms of structure making or breaking capacities of transition metal sulphates. The transition metal sulphates have been found as structure promoter in water and binary aqueous mixture of propylene glycol.

  6. Thermodynamic scaling of the shear viscosity of Mie n-6 fluids and their binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Delage-Santacreu, Stephanie [Laboratoire de Mathématiques et leurs Applications (UMR-5142 with CNRS), Université de Pau et des Pays de l’Adour, BP 1155, F-64013 PAU Cedex (France); Galliero, Guillaume, E-mail: guillaume.galliero@univ-pau.fr; Hoang, Hai; Bazile, Jean-Patrick; Boned, Christian [Laboratoire des Fluides Complexes et leurs Reservoirs (UMR-5150 with CNRS and TOTAL), Université de Pau et des Pays de l’Adour, BP 1155, F-64013 PAU Cedex (France); Fernandez, Josefa [Laboratorio de Propiedades Termofisicas, Universidade Santiago de Compostela, Campus Vida, E-15782 Santiago de Compostela (Spain)

    2015-05-07

    In this work, we have evaluated the applicability of the so-called thermodynamic scaling and the isomorph frame to describe the shear viscosity of Mie n-6 fluids of varying repulsive exponents (n = 8, 12, 18, 24, and 36). Furthermore, the effectiveness of the thermodynamic scaling to deal with binary mixtures of Mie n-6 fluids has been explored as well. To generate the viscosity database of these fluids, extensive non-equilibrium molecular dynamics simulations have been performed for various thermodynamic conditions. Then, a systematic approach has been used to determine the gamma exponent value (γ) characteristic of the thermodynamic scaling approach for each system. In addition, the applicability of the isomorph theory with a density dependent gamma has been confirmed in pure fluids. In both pure fluids and mixtures, it has been found that the thermodynamic scaling with a constant gamma is sufficient to correlate the viscosity data on a large range of thermodynamic conditions covering liquid and supercritical states as long as the density is not too high. Interestingly, it has been obtained that, in pure fluids, the value of γ is directly proportional to the repulsive exponent of the Mie potential. Finally, it has been found that the value of γ in mixtures can be deduced from those of the pure component using a simple logarithmic mixing rule.

  7. Selective Adsorption and Selective Transport Diffusion of CO2-CH4 Binary Mixture in Coal Ultramicropores.

    Science.gov (United States)

    Zhao, Yongliang; Feng, Yanhui; Zhang, Xinxin

    2016-09-06

    The adsorption and diffusion of the CO2-CH4 mixture in coal and the underlying mechanisms significantly affect the design and operation of any CO2-enhanced coal-bed methane recovery (CO2-ECBM) project. In this study, bituminous coal was fabricated based on the Wiser molecular model and its ultramicroporous parameters were evaluated; molecular simulations were established through Grand Canonical Monte Carlo (GCMC) and Molecular Dynamic (MD) methods to study the effects of temperature, pressure, and species bulk mole fraction on the adsorption isotherms, adsorption selectivity, three distinct diffusion coefficients, and diffusivity selectivity of the binary mixture in the coal ultramicropores. It turns out that the absolute adsorption amount of each species in the mixture decreases as temperature increases, but increases as its own bulk mole fraction increases. The self-, corrected, and transport diffusion coefficients of pure CO2 and pure CH4 all increase as temperature or/and their own bulk mole fractions increase. Compared to CH4, the adsorption and diffusion of CO2 are preferential in the coal ultramicropores. Adsorption selectivity and diffusivity selectivity were simultaneously employed to reveal that the optimal injection depth for CO2-ECBM is 800-1000 m at 308-323 K temperature and 8.0-10.0 MPa.

  8. The solid-liquid phase diagrams of binary mixtures of consecutive, even saturated fatty acids.

    Science.gov (United States)

    Costa, Mariana C; Sardo, Mariana; Rolemberg, Marlus P; Coutinho, João A P; Meirelles, Antonio J A; Ribeiro-Claro, Paulo; Krähenbühl, M A

    2009-08-01

    For the first time, the solid-liquid phase diagrams of five binary mixtures of saturated fatty acids are here presented. These mixtures are formed of caprylic acid (C(8:0))+capric acid (C(10:0)), capric acid (C(10:0))+lauric acid (C(12:0)), lauric acid (C(12:0))+myristic acid (C(14:0)), myristic acid (C(14:0))+palmitic acid (C(16:0)) and palmitic acid (C(16:0))+stearic acid (C(18:0)). The information used in these phase diagrams was obtained by differential scanning calorimetry (DSC), X-ray diffraction (XRD), FT-Raman spectrometry and polarized light microscopy, aiming at a complete understanding of the phase diagrams of the fatty acid mixtures. All of the phase diagrams reported here presented the same global behavior and it was shown that this was far more complex than previously imagined. They presented not only peritectic and eutectic reactions, but also metatectic reactions, due to solid-solid phase transitions common in fatty acids and regions of solid solution not previously reported. This work contributes to the elucidation of the phase behavior of these important biochemical molecules, with implications in various industrial applications.

  9. Investigating by EPR the reaction processes of intermediate products from the thermodestruction of binary mixtures of coals

    Energy Technology Data Exchange (ETDEWEB)

    Ikonomopulo, V.P.

    1983-03-01

    Binary mixtures of long-flame, gas-bituminous, coking, lean-caking, and lean coals are used to study the processes for the interaction of intermediate products of the thermodestruction of coals. The value and sign of the paramagnetic effect which occurs during simultaneous heating of coals in a binary mixture are determined by the relative position of each coal on the metamorphic scale. The possible role of plastification and reaction of the two coals in the formation of an ordered paramagnetic structure are demonstrated. 4 references.

  10. Simultaneous Detection and Estimation of Catechol, Hydroquinone, and Resorcinol in Binary and Ternary Mixtures Using Electrochemical Techniques

    Directory of Open Access Journals (Sweden)

    Md. Uzzal Hossain

    2015-01-01

    Full Text Available Cyclic voltammetry (CV and differential pulse voltammetry (DPV were performed with a glassy carbon electrode (GCE modified with polyglutamic acid (PGA on the three dihydroxybenzene isomers, catechol (CT, hydroquinone (HQ, and resorcinol (RS. At bare GCE, these isomers exhibited voltammograms with highly overlapped redox peaks that impeded their simultaneous detection in binary and ternary mixtures. On the contrary, at PGA modified GCE binary and ternary mixtures of the dihydroxybenzene isomers showed well-resolved redox peaks in both CV and DPV experiments. This resolving ability of PGA modified GCE proves its potential to be exploited as an electrochemical sensor for the simultaneous detection of these isomers.

  11. Simultaneous Detection and Estimation of Catechol, Hydroquinone, and Resorcinol in Binary and Ternary Mixtures Using Electrochemical Techniques.

    Science.gov (United States)

    Hossain, Md Uzzal; Rahman, Md Toufiqur; Ehsan, Md Qamrul

    2015-01-01

    Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were performed with a glassy carbon electrode (GCE) modified with polyglutamic acid (PGA) on the three dihydroxybenzene isomers, catechol (CT), hydroquinone (HQ), and resorcinol (RS). At bare GCE, these isomers exhibited voltammograms with highly overlapped redox peaks that impeded their simultaneous detection in binary and ternary mixtures. On the contrary, at PGA modified GCE binary and ternary mixtures of the dihydroxybenzene isomers showed well-resolved redox peaks in both CV and DPV experiments. This resolving ability of PGA modified GCE proves its potential to be exploited as an electrochemical sensor for the simultaneous detection of these isomers.

  12. Effects of binary mixtures of inducers (toluene analogs) and of metals on bioluminescence induction of a recombinant bioreporter strain.

    Science.gov (United States)

    Kong, In Chul

    2014-10-13

    This paper investigated the effects of binary mixtures of bioluminescence inducers (toluene, xylene isomers, m-toluate) and of metals (Cu, Cd, As(III), As(V), and Cr) on bioluminescence activity of recombinant (Pm-lux) strain KG1206. Different responses and sensitivities were observed depending on the types and concentrations of mixtures of inducers or metals. In the case of inducer mixtures, antagonistic and synergistic modes of action were observed, whereas metal mixtures showed all three modes of action. Antagonistic mode of action was most common for mixtures of indirect inducers, which showed bioluminescence ranging from 29% to 62% of theoretically expected effects (P(E)). On the other hand, synergistic mode of action was observed for mixtures of direct and indirect inducers, which showed bioluminescence between 141% and 243% of P(E). In the case of binary metal mixtures, bioluminescence activities were ranged from 62% to 75% and 113% to 164% of P(E) for antagonistic and synergistic modes of action, respectively (p-values 0.0001-0.038). Therefore, mixture effects could not be generalized since they were dependent on both the types and concentrations of chemicals, suggesting that biomonitoring may constitute a better strategy by investigating types and concentrations of mixture pollutants at contaminated sites.

  13. Joint effects of heavy metal binary mixtures on seed germination, root and shoot growth, bacterial bioluminescence, and gene mutation

    Institute of Scientific and Technical Information of China (English)

    In Chul Kong

    2013-01-01

    This investigation was to assess the joint effects of metal binary mixtures on seed germination,root and shoot growth,bacterial bioluminescence,and gene mutation based on the one toxic unit (1 TU) approach.Different sensitivities and orders of toxicity of metal mixtures were observed among the bioassays.In general,mostly additive or antagonistic effects were observed,while almost no synergistic effects by the binary metal mixtures in all bioassays.Therefore,the combined effects of heavy metals in the different bioassays were difficult to generalize since they were dependent on both chemical type and the organism used in each bioassay.However,these results indicate that a battery of bioassays with mixture chemicals as opposed to just a single assay with single metal is a better strategy for the bioassessment of environmental pollutants.

  14. Equilibrium and glassy states of the Asakura-Oosawa and binary hard sphere mixtures: effective fluid approach.

    Science.gov (United States)

    Germain, Ph; Amokrane, S

    2007-09-01

    Motivated by recent experimental results on model binary colloidal mixtures, especially for the glass transition, we investigate the phase diagram of two models of asymmetric binary mixtures: the hard sphere and the Asakura-Oosawa mixtures. This includes the binodals and the glass transition line, computed in the effective one-component representation using the corresponding potentials of mean force at infinite dilution. The reference hypernetted chain approximation is used for computing the static properties and the glass transition line is computed in the mode coupling approximation. The similarities and the differences between the two models are discussed for different size ratios. It is shown that while both models follow a universal behavior at large asymmetry, the hard sphere mixture model leads to more original results at moderate size ratio. These results show that a modeling beyond generic effective potentials might be necessary for an appropriate description of the complete phase diagram.

  15. Binary mixtures of waxy wheat and conventional wheat as measured by NIR reflectance.

    Science.gov (United States)

    Delwiche, Stephen R; Graybosch, Robert A

    2016-01-01

    Waxy wheat contains very low concentration (generally industries seek to have a rapid technique to ensure the purity of identity preserved waxy wheat lots. Near infrared (NIR) reflectance spectroscopy, a technique widely used in the cereals industry for proximate analysis, is a logical candidate for measuring contamination level and thus is the subject of this study. Two sets of wheat samples, harvested, prepared and scanned one year apart, were used to evaluate the NIR concept. One year consisted of nine pairs of conventional:waxy preparations, with each preparation consisting of 29 binary mixtures ranging in conventional wheat fraction (by weight) of 0-100% (261 spectral samples). The second year was prepared in the same fashion, with 12 preparations, thus producing 348 spectral samples. One year's samples were controlled for protein content and moisture level between pair components in order to avoid the basis for the conventional wheat fraction models being caused by something other than spectral differences attributed to waxy and nonwaxy endosperm. Likewise the second year was controlled by selection of conventional wheat for mixture preparation based on either protein content or cluster analysis of principal components of candidate spectra. Partial least squares regression, one and two-term linear regression, and support vector machine regression models were examined. Validation statistics arising from sets within the same year or across years were remarkably similar, as were those among the three regression types. A single wavelength on second derivative transformed spectra, namely 2290 nm, was effective at estimating the mixture level by weight, with standard errors of performance in the 6-9% range. Thus, NIR spectroscopy may be used for measuring conventional hard wheat 'contamination' in waxy wheat at mixture levels above 10% w/w.

  16. Effects of the Wetting Particles on Phase Separation of Binary Mixtures

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-Wen; MA Yu-qiang

    2000-01-01

    We study phase separation of binary mixtures in the presence of mobile particles by the lattice Monte Carlo simulation. The presence of mobile particles changes tile morphology of the domain growth, in agreement with earlier experimental result. By varying the wetting interaction strength, we can control the speed of phase separation, and find a critical wetting strength beyond which the growth of the domains slows down. We propose a novel scaling function which describes the growth of the domain size L(t) as a function of time. It suggests an applicable way to tune the speed of phase separation by the coupling between the phase decomposition and the mobile particle-wetting process.

  17. Biosorption of binary mixtures of copper and cobalt by Penicillium brevicompactum.

    Science.gov (United States)

    Tsekova, Kolishka; Ianis, Maria; Dencheva, Vera; Ganeva, Sonya

    2007-01-01

    This work reports on a study of the biosorption of copper and cobalt, both singly and in combination (in equimolar concentrations), by the resting cells of Penicillium brevicompactum. Equilibrium batch sorption studies were carried out at 30 degrees C and pH 5.0 for a contact time of 1 hour to guarantee that equilibrium was reached. The equilibrium data were analyzed using the Langmuir and Freundlich isotherms. The adsorption of binary mixtures of heavy metal solutions on the fungal biomass was found to be of competitive type where the adsorption capacity for any single metal decreased in the presence of the other. The cobalt ions showed a higher affinity for Penicillium brevicompactum than the copper ions.

  18. Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex.

    Science.gov (United States)

    Asselman, J; Janssen, C R; Smagghe, G; De Schamphelaere, K A C

    2014-05-01

    In aquatic ecosystems, mixtures of chemical and natural stressors can occur which may significantly complicate risk assessment approaches. Here, we show that effects of binary combinations of four different insecticides and Microcystis aeruginosa, a toxic cyanobacteria, on Daphnia pulex exhibited distinct interaction patterns. Combinations with chlorpyrifos and tetradifon caused non-interactive effects, tebufenpyrad caused an antagonistic interaction and fenoyxcarb yielded patterns that depended on the reference model used (i.e. synergistic with independent action, additive with concentration addition). Our results demonstrate that interactive effects cannot be generalised across different insecticides, not even for those targeting the same biological pathway (i.e. tebufenpyrad and tetradifon both target oxidative phosphorylation). Also, the concentration addition reference model provided conservative predictions of effects in all investigated combinations for risk assessment. These predictions could, in absence of a full mechanistic understanding, provide a meaningful solution for managing water quality in systems impacted by both insecticides and cyanobacterial blooms.

  19. Order parameter and its critical exponent for some binary mixtures showing induced nematic phase

    Science.gov (United States)

    Sarkar, Sudipta Kumar; Das, Malay Kumar

    2016-09-01

    Refractive index measurements as a function of temperature have been performed for an induced nematic binary system by means of thin prism technique. The temperature dependence of the birefringence (Δn) has been assessed from the measured refractive index data. A direct extrapolation method has been employed to determine the orientational order parameter for the investigated mixtures and the order parameter so obtained has also been compared with the mean field values. The Haller type fitting expression results in a relatively lower value of the order parameter critical exponent (β) compared to the theoretically predicted values. Therefore, a four-parameter power law expression, consistent with the mean field theory as well as the first-order character of the nematic-isotropic (N-I) phase transition have been used to explore the critical behavior of the order parameter near the N-I transition.

  20. Benchmark solutions for transport in $d$-dimensional Markov binary mixtures

    CERN Document Server

    Larmier, Coline; Malvagi, Fausto; Mazzolo, Alain; Zoia, Andrea

    2016-01-01

    Linear particle transport in stochastic media is key to such relevant applications as neutron diffusion in randomly mixed immiscible materials, light propagation through engineered optical materials, and inertial confinement fusion, only to name a few. We extend the pioneering work by Adams, Larsen and Pomraning \\cite{benchmark_adams} (recently revisited by Brantley \\cite{brantley_benchmark}) by considering a series of benchmark configurations for mono-energetic and isotropic transport through Markov binary mixtures in dimension $d$. The stochastic media are generated by resorting to Poisson random tessellations in $1d$ slab, $2d$ extruded, and full $3d$ geometry. For each realization, particle transport is performed by resorting to the Monte Carlo simulation. The distributions of the transmission and reflection coefficients on the free surfaces of the geometry are subsequently estimated, and the average values over the ensemble of realizations are computed. Reference solutions for the benchmark have never be...

  1. Decomposition driven interface evolution for layers of binary mixtures: I. Model derivation and stratified base states

    CERN Document Server

    Thiele, Uwe; Frastia, Lubor

    2007-01-01

    A dynamical model is proposed to describe the coupled decomposition and profile evolution of a free surface film of a binary mixture. An example is a thin film of a polymer blend on a solid substrate undergoing simultaneous phase separation and dewetting. The model is based on model-H describing the coupled transport of the mass of one component (convective Cahn-Hilliard equation) and momentum (Navier-Stokes-Korteweg equations) supplemented by appropriate boundary conditions at the solid substrate and the free surface. General transport equations are derived using phenomenological non-equilibrium thermodynamics for a general non-isothermal setting taking into account Soret and Dufour effects and interfacial viscosity for the internal diffuse interface between the two components. Focusing on an isothermal setting the resulting model is compared to literature results and its base states corresponding to homogeneous or vertically stratified flat layers are analysed.

  2. Air-Driven Segregation in Binary Granular Mixtures with Same Size but Different Densities

    Institute of Scientific and Technical Information of China (English)

    LU Chang-Hong; SHI Qing-Fan; YANG Lei; SUN Gang

    2008-01-01

    We investigate the segregation effect of binary granular mixtures with the same size but different densities under vibration at different air pressures. Our experiments show that the segregation state is seriously dependent on the air pressure and there is a new type of partially segregated state at high air pressure, which has the characteristic that the lighter grains tend to stay at the bottom and form a pure layer, while heavier grains and remained lighter ones tend to rise and to form a mixed layer on the top of the system. We redefine the order parameter to study the variation of the segregation effect with the air pressure and vibration parameter in detail. Finally, the mechanism of the air-driven segregation is illustrated by the faster acceleration due to the airflow through the granular bed for lighter particles.

  3. Phase behavior of binary polybutadiene copolymer mixtures as an example of weakly interacting polymers

    CERN Document Server

    Schwahn, D

    2002-01-01

    Binary blends of statistical polybutadiene copolymers of different vinyl content and molar volume were explored by small-angle neutron scattering. These samples represent the most simple class of statistical copolymer mixtures. In spite of this simplicity, changes in vinyl content, molar volume, and deuterium and hydrogen content of the chains give rise to strong effects; phase separation occurs from minus 230 C to more than plus 200 C and can even reverse from an enthalpically driven one at low temperatures to an entropically driven one at high temperatures. The entropic and enthalpic terms of the Flory-Huggins parameter as determined from the experiment are in excellent agreement with lattice cluster theory calculations. (orig.)

  4. Influence of through-flow on linear pattern formation properties in binary mixture convection

    CERN Document Server

    Jung, C; Büchel, P; Jung, Ch.

    1996-01-01

    We investigate how a horizontal plane Poiseuille shear flow changes linear convection properties in binary fluid layers heated from below. The full linear field equations are solved with a shooting method for realistic top and bottom boundary conditions. Through-flow induced changes of the bifurcation thresholds (stability boundaries) for different types of convective solutions are deter- mined in the control parameter space spanned by Rayleigh number, Soret coupling (positive as well as negative), and through-flow Reynolds number. We elucidate the through-flow induced lifting of the Hopf symmetry degeneracy of left and right traveling waves in mixtures with negative Soret coupling. Finally we determine with a saddle point analysis of the complex dispersion relation of the field equations over the complex wave number plane the borders between absolute and convective instabilities for different types of perturbations in comparison with the appropriate Ginzburg-Landau amplitude equation approximation. PACS:47.2...

  5. A comparative study of non-linearity parameter for binary liquid mixtures

    Indian Academy of Sciences (India)

    J D Pandey; Ranjan Dey; Vinay Sanguri; Jyotsna Chhabra; Tanuja Nautiyal

    2005-09-01

    The present investigation comprises of theoretical evaluation of acoustic non-linearity parameter, / for equimolar binary mixtures, viz. chlorobenzene or 1-chloronaphthalene with a series of normal alkanes (n-C, = 6, 8, 10, 12, 14, 16), and with a series of highly branched alkanes (br-C, = 6, 8, 12, 16), viz. 2,2-dimethylbutane (br-C6), 2,2,4-trimethylpentane (br-C8), 2,2,4,6,6-pentamethylheptane (br-C12) and 2,2,4,4,6,8,8-heptamethylnonane (br-C16). Tong and Dong method, ther- moacoustical method, Hartmann relation and Ballou relation have been employed to evaluate /. A comparative study of / values obtained from the aforementioned methods has been made. The results are discussed on the basis of structural orientations of normal and branched alkanes.

  6. The influence of thermodynamic self-consistency on the phase behaviour of symmetric binary mixtures

    CERN Document Server

    Scholl-Paschinger, E; Kahl, G

    2004-01-01

    We have investigated the phase behaviour of a symmetric binary mixture with particles interacting via hard-core Yukawa potentials. To calculate the thermodynamic properties we have used the mean spherical approximation (MSA), a conventional liquid state theory, and the closely related self-consistent Ornstein-Zernike approximation which is defined via an MSA-type closure relation, requiring, in addition, thermodynamic self-consistency between the compressibility and the energy-route. We investigate on a quantitative level the effect of the self-consistency requirement on the phase diagram and on the critical behaviour and confirm the existence of three archetypes of phase diagram, which originate from the competition between the first order liquid/vapour transition and the second order demixing transition.

  7. MONOMOLECULAR FILMS OF COPOLYMERS OF OXYETHYLENE AND OXYPROPYLENE,POLYPROPYLENE GLYCOL AND THEIR BINARY MIXTURES

    Institute of Scientific and Technical Information of China (English)

    LI Wailang; DING Faxiang; GU Tiren

    1989-01-01

    The behaviour of monolayers of copolymers of oxyethylene and oxypropylene (UH29 and UH68),polypropylene glycol (UHPPG) and their binary mixtures on air-water interface has been investigated carefully on compression -expansion cycles. The first compression isotherm is approximately an equilibrium one. In the UHPPG-UH29 and UHPPG -UH68 systems, the calculated average π-a curves based on simple additivity ofthe two individual components coincide with the experimental results reasonably well. It is suggested that the two components are miscible and form near- ideal solution at the air- water interface.The compression- expansion cycle experiments shows some degree of hysteresis. The order of degree of hysteresis for individual components is UH68 > UH29 > UHPPG. The explanation for the hysteresis is proposed.

  8. Effect of estrogenic binary mixtures in the yeast estrogen screen (YES).

    Science.gov (United States)

    Ramirez, Tzutzuy; Buechse, Andreas; Dammann, Martina; Melching-Kollmuß, Stephanie; Woitkowiak, Claudia; van Ravenzwaay, Bennard

    2014-10-01

    Endocrine disrupting compounds (EDCs) of natural or synthetic origin can interfere with the balance of the hormonal system, either by altering hormone production, secretion, transport, or their binding and consequently lead to an adverse outcome in intact animals. An important aspect is the prediction of effects of combined exposure to two or more EDCs at the same time. The yeast estrogen assay (YES) is a broadly used method to assess estrogenic potential of chemicals. Besides exhibiting good predictivity to identify compounds which interfere with the estrogen receptor, it is easy to handle, rapid and therefore allows screening of a large number of single compounds and varying mixtures. Herein, we applied the YES assay to determine the potential combination effects of binary mixtures of two estrogenic compounds, bisphenol A and genistein, as well as one classical androgen that in vitro also exhibits estrogenic activity, trenbolone. In addition to generating data from combined exposure, we fitted these to a four-parametric logistic dose-response model. As all compounds tested share the same mode of action dose additivity was expected. To assess this, the Loewe model was utilized. Deviations between the Loewe additivity model and the observed responses were always small and global tests based on the whole dose-response data set indicated in general a good fit of the Loewe additivity model. At low concentrations concentration additivity was observed, while at high concentrations, the observed effect was lower than additivity, most likely reflecting receptor saturation. In conclusion, our results suggest that binary combinations of genistein, bisphenol A and trenbolone in the YES assay do not deviate from expected additivity.

  9. Structure and dynamics of binary liquid mixtures near their continuous demixing transitions

    Science.gov (United States)

    Roy, Sutapa; Dietrich, S.; Höfling, Felix

    2016-10-01

    The dynamic and static critical behavior of a family of binary Lennard-Jones liquid mixtures, close to their continuous demixing points (belonging to the so-called model H' dynamic universality class), are studied computationally by combining semi-grand canonical Monte Carlo simulations and large-scale molecular dynamics (MD) simulations, accelerated by graphic processing units (GPU). The symmetric binary liquid mixtures considered cover a variety of densities, a wide range of compressibilities, and various interactions between the unlike particles. The static quantities studied here encompass the bulk phase diagram (including both the binodal and the λ-line), the correlation length, and the concentration susceptibility, of the finite-sized systems above the bulk critical temperature Tc, the compressibility and the pressure at Tc. Concerning the collective transport properties, we focus on the Onsager coefficient and the shear viscosity. The critical power-law singularities of these quantities are analyzed in the mixed phase (above Tc) and non-universal critical amplitudes are extracted. Two universal amplitude ratios are calculated. The first one involves static amplitudes only and agrees well with the expectations for the three-dimensional Ising universality class. The second ratio includes also dynamic critical amplitudes and is related to the Einstein-Kawasaki relation for the interdiffusion constant. Precise estimates of this amplitude ratio are difficult to obtain from MD simulations, but within the error bars our results are compatible with theoretical predictions and experimental values for model H'. Evidence is reported for an inverse proportionality of the pressure and the isothermal compressibility at the demixing transition, upon varying either the number density or the repulsion strength between unlike particles.

  10. Composition dependence of the glass forming ability in binary mixtures: The role of demixing entropy.

    Science.gov (United States)

    Nandi, Ujjwal Kumar; Banerjee, Atreyee; Chakrabarty, Suman; Bhattacharyya, Sarika Maitra

    2016-07-21

    We present a comparative study of the glass forming ability of binary systems with varying composition, where the systems have similar global crystalline structure (CsCl+fcc). Biased Monte Carlo simulations using umbrella sampling technique show that the free energy cost to create a CsCl nucleus increases as the composition of the smaller particles is decreased. We find that systems with comparatively lower free energy cost to form CsCl nucleus exhibit more pronounced pre-crystalline demixing near the liquid/crystal interface. The structural frustration between the CsCl and fcc crystal demands this demixing. We show that closer to the equimolar mixture, the entropic penalty for demixing is lower and a glass forming system may crystallize when seeded with a nucleus. This entropic penalty as a function of composition shows a non-monotonic behaviour with a maximum at a composition similar to the well known Kob-Anderson (KA) model. Although the KA model shows the maximum entropic penalty and thus maximum frustration against CsCl formation, it also shows a strong tendency towards crystallization into fcc lattice of the larger "A" particles which can be explained from the study of the energetics. Thus for systems closer to the equimolar mixture although it is the requirement of demixing which provides their stability against crystallization, for KA model it is not demixing but slow dynamics and the presence of the "B" particles make it a good glass former. The locally favoured structure around "B" particles is quite similar to the CsCl structure and the incompatibility of CsCl and fcc hinders the fcc structure growth in the KA model. Although the glass forming binary systems studied here are quite similar, differing only in composition, we find that their glass forming ability cannot be attributed to a single phenomenon.

  11. Composition dependence of the glass forming ability in binary mixtures: The role of demixing entropy

    Science.gov (United States)

    Nandi, Ujjwal Kumar; Banerjee, Atreyee; Chakrabarty, Suman; Bhattacharyya, Sarika Maitra

    2016-07-01

    We present a comparative study of the glass forming ability of binary systems with varying composition, where the systems have similar global crystalline structure (CsCl+fcc). Biased Monte Carlo simulations using umbrella sampling technique show that the free energy cost to create a CsCl nucleus increases as the composition of the smaller particles is decreased. We find that systems with comparatively lower free energy cost to form CsCl nucleus exhibit more pronounced pre-crystalline demixing near the liquid/crystal interface. The structural frustration between the CsCl and fcc crystal demands this demixing. We show that closer to the equimolar mixture, the entropic penalty for demixing is lower and a glass forming system may crystallize when seeded with a nucleus. This entropic penalty as a function of composition shows a non-monotonic behaviour with a maximum at a composition similar to the well known Kob-Anderson (KA) model. Although the KA model shows the maximum entropic penalty and thus maximum frustration against CsCl formation, it also shows a strong tendency towards crystallization into fcc lattice of the larger "A" particles which can be explained from the study of the energetics. Thus for systems closer to the equimolar mixture although it is the requirement of demixing which provides their stability against crystallization, for KA model it is not demixing but slow dynamics and the presence of the "B" particles make it a good glass former. The locally favoured structure around "B" particles is quite similar to the CsCl structure and the incompatibility of CsCl and fcc hinders the fcc structure growth in the KA model. Although the glass forming binary systems studied here are quite similar, differing only in composition, we find that their glass forming ability cannot be attributed to a single phenomenon.

  12. Solubility and solution thermodynamics of 2,5-thiophenedicarboxylic acid in (water + ethanol) binary solvent mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang; Zhang, Qi; Cao, Cuicui; Cheng, Limin [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Shi, Ying [Taiyuan Qiaoyou Chemical Industrial Co. Ltd., Taiyuan 030025 (China); Yang, Wenge [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Hu, Yonghong, E-mail: yonghonghu11@126.com [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China)

    2014-09-20

    Highlights: • The solubility increased with increasing temperature. • The solubility decreased with the rise of the ratio of the water. • The solubility data were fitted using Apelblat equation, CNIBS/R–K and JA model. • The Gibbs energy, enthalpy and entropy were calculated by the van’t Hoff analysis. - Abstract: In this paper, we focused on solubility and solution thermodynamics of 2,5-thiophenedicarboxylic acid. By gravimetric method, the solubility of 2,5-thiophenedicarboxylic acid was measured in (water + ethanol) binary solvent mixtures from 278.15 K to 333.15 K under atmosphere pressure. The solubility data were fitted using modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R–K) model and Jouyban–Acree model. Computational results showed that the modified Apelblat equation has the lowest MD (mean deviation). In addition, the thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van’t Hoff analysis.

  13. Quantifying the rates of relaxation of binary mixtures of amorphous pharmaceuticals with isothermal calorimetry.

    Science.gov (United States)

    Alem, Naziha; Beezer, Anthony E; Gaisford, Simon

    2010-10-31

    While the use of isothermal calorimetry to quantify the rate of relaxation of one-phase amorphous pharmaceuticals, through application of models, is well documented, the resolution of the models to detect and quantify relaxation in systems containing two independent amorphous phases is not known. Addressing this knowledge gap is the focus of this work. Two fitting models were tested; the Kohlrausch-Williams-Watts model (KWW) and the modified-stretch exponential (MSE). The ability of each model to resolve relaxation processes in binary systems was determined with simulated calorimetric data. It was found that as long as the relaxation time constants of the relaxation processes were with 10(3) of each other, the models could determine that two events were occurring and could quantify the correct reaction parameters of each. With greater differences in the time constants, the faster process always dominates the data and the resolving power of the models is lost. Real calorimetric data were then obtained for two binary amorphous systems (sucrose-lactose and sucrose-indomethacin mixtures). The relaxation behaviour of all the single components was characterised as they relaxed individually to provide reference data. The ability of the KWW model to recover the expected relaxation parameters for two component data was impaired because of their inherently noisy nature. The MSE model reasonably recovered the expected parameters for each component for the sucrose-indomethacin system but not for the sucrose-lactose system, which may indicate a possible interaction in that case.

  14. The Spatiotemporal Oscillations of Order Parameter for Isothermal Model of the Surface-Directed Spinodal Decomposition in Bounded Binary Mixtures

    Directory of Open Access Journals (Sweden)

    Igor B. Krasnyuk

    2009-01-01

    Full Text Available The asymptotical behavior of order parameter in confined binary mixture is considered in one-dimensional geometry. The interaction between bulk and surface forces in the mixture is investigated. Its established conditions are when the bulk spinodal decomposition may be ignored and when the main role in the process of formation of the oscillating asymptotic periodic spatiotemporal structures plays the surface-directed spinodal decomposition which is modelled by nonlinear dynamical boundary conditions.

  15. Poisson-Helmholtz-Boltzmann model of the electric double layer: analysis of monovalent ionic mixtures.

    Science.gov (United States)

    Bohinc, Klemen; Shrestha, Ahis; Brumen, Milan; May, Sylvio

    2012-03-01

    In the classical mean-field description of the electric double layer, known as the Poisson-Boltzmann model, ions interact exclusively through their Coulomb potential. Ion specificity can arise through solvent-mediated, nonelectrostatic interactions between ions. We employ the Yukawa pair potential to model the presence of nonelectrostatic interactions. The combination of Yukawa and Coulomb potential on the mean-field level leads to the Poisson-Helmholtz-Boltzmann model, which employs two auxiliary potentials: one electrostatic and the other nonelectrostatic. In the present work we apply the Poisson-Helmholtz-Boltzmann model to ionic mixtures, consisting of monovalent cations and anions that exhibit different Yukawa interaction strengths. As a specific example we consider a single charged surface in contact with a symmetric monovalent electrolyte. From the minimization of the mean-field free energy we derive the Poisson-Boltzmann and Helmholtz-Boltzmann equations. These nonlinear equations can be solved analytically in the weak perturbation limit. This together with numerical solutions in the nonlinear regime suggests an intricate interplay between electrostatic and nonelectrostatic interactions. The structure and free energy of the electric double layer depends sensitively on the Yukawa interaction strengths between the different ion types and on the nonelectrostatic interactions of the mobile ions with the surface.

  16. Ether and siloxane functionalized ionic liquids and their mixtures as electrolyte for lithium-ion batteries.

    Science.gov (United States)

    Chavan, Santosh N; Tiwari, Aarti; Nagaiah, Tharamani C; Mandal, Debaprasad

    2016-06-28

    The present study deals with an investigation of two novel imidazolium ionic liquids bearing ether-ether (1O2O2-Im-2O1) or ether-siloxane (1O2O2-Im-1SiOSi) functionalities with TFSI anion and their mixtures with propylene carbonate as electrolytes in lithium-ion batteries. The electrochemical stability and conductivity of these novel ILs were analyzed by electrochemical studies, such as cyclic voltammetry, linear sweep voltammetry and impedance measurements. The applicability of these ILs as electrolytes in Li-ion batteries was studied in the presence of a high concentration of LiTFSI (1 mol kg(-1) electrolyte) and the ether-ether IL was shown to possess a high electrochemical stability window (ESW) of 5.9 V and good conductivity of 2.2 mS cm(-1). The electrochemical stability and conductivity were further complimented by self-diffusion of different ions using pulsed gradient spin-echo (PGSE) NMR, viscosity and thermal properties like TGA and DSC analysis. More importantly, we explored the effect of temperature on the electrochemical stability and conductivity of these ILs by electrochemical impedance spectroscopy.

  17. Electrophoretic separations in poly(dimethylsiloxane) microchips using mixtures of ionic, nonionic and zwitterionic surfactants.

    Science.gov (United States)

    Guan, Qian; Noblitt, Scott D; Henry, Charles S

    2012-09-01

    The use of surfactant mixtures to affect both EOF and separation selectivity in electrophoresis with PDMS substrates is reported, and capacitively coupled contactless conductivity detection is introduced for EOF measurement on PDMS microchips. First, the EOF was measured for two nonionic surfactants (Tween 20 and Triton X-100), mixed ionic/nonionic surfactant systems (SDS/Tween 20 and SDS/Triton X-100), and finally for the first time, mixed zwitterionic/nonionic surfactant systems (TDAPS/Tween 20 and TDAPS/Triton X-100). EOF for the nonionic surfactants decreased with increasing surfactant concentration. The addition of SDS or TDAPS to a nonionic surfactant increased EOF. After establishing the EOF behavior, the separation of model catecholamines was explored to show the impact on separations. Similar analyte resolution with greater peak heights was achieved with mixed surfactant systems containing Tween 20 and TDAPS relative to the single surfactant system. Finally, the detection of catecholamine release from PC12 cells by stimulation with 80 mM K(+) was performed to demonstrate the usefulness of mixed surfactant systems to provide resolution of biological compounds in complex samples.

  18. Electrophoretic separations in poly(dimethylsiloxane) microchips using a mixture of ionic and zwitterionic surfactants.

    Science.gov (United States)

    Guan, Qian; Noblitt, Scott D; Henry, Charles S

    2012-01-01

    The use of mixtures of ionic and zwitterionic surfactants in poly(dimethylsiloxane) (PDMS) microchips is reported. The effect of surfactant concentration on electroosmotic flow (EOF) was studied for a single anionic surfactant (sodium dodecyl sulfate, SDS), a single zwitterionic surfactant (N-tetradecylammonium-N,N-dimethyl-3-ammonio-1-propanesulfonate, TDAPS), and a mixed SDS/TDAPS surfactant system. SDS increased the EOF as reported previously while TDAPS showed an initial increase in EOF followed by a reduction at higher concentrations. When TDAPS was added to a solution containing SDS, the EOF decreased in a concentration-dependent manner. The EOF for all three surfactant systems followed expected pH trends, with increasing EOF at higher pH. The mixed surfactant system allowed tuning of the EOF across a range of pH and concentration conditions. After establishing the EOF behavior, the adsorption/desorption kinetics were measured and showed a slower adsorption/desorption rate for TDAPS than SDS. Finally, the separation and electrochemical detection of model catecholamines in buffer and reduced glutathione in red blood cell lysate using the mixed surfactant system were explored. The mixed surfactant system provided shorter analysis times and/or improved resolution when compared to the single surfactant systems.

  19. The structure of n-alkane binary mixtures adsorbed on graphite

    Energy Technology Data Exchange (ETDEWEB)

    Espeau, Philippe [Laboratoire de Chimie Physique et Minerale, Faculte de Pharmacie, Universite Rene Descartes-Paris V, F-75006 Paris (France)]. E-mail: philippe.espeau@univ-paris5.fr; White, John W. [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia); Papoular, Robert J. [Laboratoire Leon Brillouin, CEA-CEN Saclay, F-91191 Gif-sur-Yvette Cedex (France)

    2005-12-15

    The thermodynamics and structure of the surface adsorbed phase in binary C15-C16 and C15-C17 n-alkane mixtures confined in graphite pores have been studied by differential scanning calorimetry and small-angle X-ray scattering. The previously observed selective adsorption of the longer alkane for chain length differences greater than five carbon atoms is verified but reduced for chain length differences less than or equal to two. With a difference in chain length of one carbon atom, Vegard's law is followed for the melting points of the adsorbed mixture and the (0 2) d-spacing is a continuous function of the mole fraction x. With a two-carbon atom difference, samples aged for 1 week have a lamellar structure for which the entities A{sub 1-x}B {sub x} try to be commensurate with the substrate. The same samples aged for 1 month show a continuous parabolic x-dependence for both the melting points and the d-spacings. An explanation in terms of selective probability of adsorption is proposed based on crystallographic considerations.

  20. Atomic capture and transfer of negative pions stopped in binary mixtures of hydrogen with polyatomic gases

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyev, V.A.; Levay, B.; Minkova, A.; Petrukhin, V.I.; Horvath, D.

    1985-12-01

    The atomic capture and transfer of stopped negative pions have been studied in binary gas mixtures of H/sub 2/+M, where M is CCl/sub 2/F/sub 2/, CClF/sub 3/, CBrF/sub 3/ or SF/sub 6/. The ..pi../sup 0/ yield, versus relative atomic concentration Csub(A) of M, goes through a maximum at Csub(A)proportional0.1 and levels off at zero at high concentrations. This phenomenon together with other observed characteristics of the atomic capture and transfer of pions in these systems is interpreted in the frame of a phenomenological model. The average transfer coefficients anti ..lambda..sub(Z) exhibit a weak concentration dependence. The estimated average atomic capture ratios anti A(Z/H) are lower than those found for noble gases, probably because of the mutual screening of the constituent atoms in the molecules. The probability of pion capture in an atomic orbit is not proportional to the stopping power of the components of the mixture. (orig.).

  1. Solubility of Stevioside and Rebaudioside A in water, ethanol and their binary mixtures

    Directory of Open Access Journals (Sweden)

    Liliana S. Celaya

    2016-10-01

    Full Text Available In order to investigate the solubility of Stevioside and Rebaudioside A in different solvents (ethanol, water, ethanol:water 30:70 and ethanol:water 70:30, supersaturated solutions of pre-crystalized steviol glycosides were maintained at different temperatures (from 5 °C to 50 °C to reach equilibrium. Under these conditions significant differences were found in the extent of solubility. Rebaudioside A was poorly soluble in ethanol and water, and Stevioside was poorly soluble in water. Solvent mixtures more effectively promoted solubilisation, and a significant effect of temperature on solubility was observed. The two steviol glycosides showed higher solubilities and this behavior was promoted by the presence of the other sweetener. The polarity indices of the solvents were determined, and helped to explain the observed behavior. Several solute-solvent and solute-solute interactions can occur, along with the incidence of a strong affinity between solvents. The obtained results are in accordance with technological applications of ethanol, water and their binary mixtures for Stevioside and Rebaudioside A separations.

  2. Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

    CERN Document Server

    Bates, Richard; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Da Riva, Enrico; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

    2014-01-01

    We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 ×10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to proce...

  3. Suppression of turbulent energy cascade due to phase separation in homogenous binary mixture fluid

    Science.gov (United States)

    Takagi, Youhei; Okamoto, Sachiya

    2015-11-01

    When a multi-component fluid mixture becomes themophysically unstable state by quenching from well-melting condition, phase separation due to spinodal decomposition occurs, and a self-organized structure is formed. During phase separation, free energy is consumed for the structure formation. In our previous report, the phase separation in homogenous turbulence was numerically simulated and the coarsening process of phase separation was discussed. In this study, we extended our numerical model to a high Schmidt number fluid corresponding to actual polymer solution. The governing equations were continuity, Navier-Stokes, and Chan-Hiliard equations as same as our previous report. The flow filed was an isotropic homogenous turbulence, and the dimensionless parameters in the Chan-Hilliard equation were estimated based on the thermophysical condition of binary mixture. From the numerical results, it was found that turbulent energy cascade was drastically suppressed in the inertial subrange by phase separation for the high Schmidt number flow. By using the identification of turbulent and phase separation structure, we discussed the relation between total energy balance and the structures formation processes. This study is financially supported by the Grand-in-Aid for Young Scientists (B) (No. T26820045) from the Ministry of Education, Cul-ture, Sports, Science and Technology of Japan.

  4. A poromechanical model for coal seams saturated with binary mixtures of CH4 and CO2

    Science.gov (United States)

    Nikoosokhan, Saeid; Vandamme, Matthieu; Dangla, Patrick

    2014-11-01

    Underground coal bed reservoirs naturally contain methane which can be produced. In parallel of the production of this methane, carbon dioxide can be injected, either to enhance the production of methane, or to have this carbon dioxide stored over geological periods of time. As a prerequisite to any simulation of an Enhanced Coal Bed Methane recovery process (ECBM), we need state equations to model the behavior of the seam when cleats are saturated with a miscible mixture of CH4 and CO2. This paper presents a poromechanical model of coal seams exposed to such binary mixtures filling both the cleats in the seam and the porosity of the coal matrix. This model is an extension of a previous work which dealt with pure fluid. Special care is dedicated to keep the model consistent thermodynamically. The model is fully calibrated with a mix of experimental data and numerical data from molecular simulations. Predicting variations of porosity or permeability requires only calibration based on swelling data. With the calibrated state equations, we predict numerically how porosity, permeability, and adsorbed amounts of fluid vary in a representative volume element of coal seam in isochoric or oedometric conditions, as a function of the pressure and of the composition of the fluid in the cleats.

  5. An Exercise on Calibration: DRIFTS Study of Binary Mixtures of Calcite and Dolomite with Partially Overlapping Spectral Features

    Science.gov (United States)

    De Lorenzi Pezzolo, Alessandra

    2013-01-01

    Unlike most spectroscopic calibrations that are based on the study of well-separated features ascribable to the different components, this laboratory experience is especially designed to exploit spectral features that are nearly overlapping. The investigated system consists of a binary mixture of two commonly occurring minerals, calcite and…

  6. ETHANOL, ACETIC ACID, AND WATER ADSORPTION FROM BINARY AND TERNARY LIQUID MIXTURES ON HIGH-SILICA ZEOLITES

    Science.gov (United States)

    Adsorption isotherms were measured for ethanol, acetic acid, and water adsorbed on high-silica ZSM-5 zeolite powder from binary and ternary liquid mixtures at room temperature. Ethanol and water adsorption on two high-silica ZSM-5 zeolites with different aluminum contents and a h...

  7. Long-term effects of a binary mixture of perfluorooctane sulfonate (PFOS) and bisphenol A (BPA) in zebrafish (Danio rerio)

    DEFF Research Database (Denmark)

    Keiter, Susanne; Baumann, Lisa; Farber, H;

    2012-01-01

    aimed at evaluating the long-term effects and toxicity-increasing behavior of PFOS in vivo using the zebrafish (Danio rerio). Fish were maintained in flow-through conditions and exposed to single and binary mixtures of PFOS and the endocrine disruptor bisphenol A (BPA) at nominal concentrations of 0...

  8. Enhanced toxicity of binary mixtures of larvicidal constituents from Asarum heterotropoides root to Culex pipiens pallens (Diptera: Culicidae).

    Science.gov (United States)

    Perumalsamy, Haribalan; Kim, Jun-Ran; Kim, Soon-Il; Kwon, Hyung Wook; Ahn, Young-Joon

    2012-01-01

    The toxicity of pellitorine alone or in combination with (-)-asarinin, alpha-asarone, methyleugenol, or pentadecane (1:1, 1:2, 1:3, 2:1, and 3:1 ratios) to third instars from an insecticide-susceptible KS-CP strain and -resistant DJ-CP colony of Culex pipiens pallens Coquillett was evaluated using a direct-contact mortality bioassay. The binary mixture of pellitorine and (-)-asarinin (3:1 ratio) was significantly more toxic against KS-CP larvae (0.95 mg/liter) and DJ-CP larvae (1.07 mg/liter) than either pellitorine (2.08 mg/liter for KS-CP and 2.33 mg/liter for DJ-CP) or (-)-asarinin (11.45 and 12.61 mg/liter) alone. The toxicity of the other binary mixtures (1:1, 1:2, 1:3, and 2:1 ratios) and pellitorine did not differ significantly from each other. Based on the co-toxicity coefficient (CC) and synergistic factor (SF), the three binary mixtures (1:3, 2:1, and 3:1) operated synergistically (CC, 250-390 and SF, 1.4-2.2 for KS-CP; CC, 257-279 and SF, 1.1-2.1 for DJ-CP). The binary mixtures of pellitorine and (-)-asarinin merit further study as potential larvicides for the control of insecticide-resistant mosquito populations.

  9. Crystal nucleation in binary hard-sphere mixtures: the effect of order parameter on the cluster composition

    NARCIS (Netherlands)

    Ni, R.; Smallenburg, F.; Filion, L.C.; Dijkstra, M.

    2011-01-01

    We study crystal nucleation in a binary mixture of hard spheres and investigate the composition and size of the (non)critical clusters using Monte Carlo simulations. In order to study nucleation of a crystal phase in computer simulations, a one-dimensional order parameter is usually defined to ident

  10. Enhanced KR-Fundamental Measure Functional for Inhomogeneous Binary and Ternary Hard Sphere Mixtures

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shi-Qi

    2011-01-01

    An enhanced KR-fundarnentai measure functional (FMF) is elaborated and employed to investigate binary and ternary hard sphere fluids near a planar hard wall or confined within two planar hard wails separated by certain interval.The present enhanced KR-FMF incorporates respectively, for aim of comparison, a recent 3rd-order expansion equation of state (EOS) and a Boublik's extension of Kolafa's EOS for HS mixtures.It is indicated that the two versions of the EOS lead to, in the framework of the enhanced KR-FMF, similar density profiles, but the 3rd-order EOS is more consistent with an exact scaled particle theory (SPT) relation than the BK EOS.Extensive comparison between the enhanced KR-FMF-3rd-order EOS predictions and corresponding density profiles produced in different periods indicates the excellent performance of the present enhanced KR-FMF-3rd-order EOS in comparison with other available density functional approximations (DFAs).There are two anomalous situations from whose density profiles all DFAs studied deviate significantly; however, subsequent new computer simulation results for state conditions similar to the two anomalous situations are in very excellent agreement with the present enhanced KR-FMF-3rd-order EOS.The present paper indicates that (i) the validity of the “naive” substitution elaborated in the present paper and peculiar to the original KR-FMF is still in operation even if inhomogeneous mixtures are being dealt with; (ii) the high accuracy and seff-consistency of the third order EOS seem to allow for application of the KR-FMF-third order EOS to more severe state conditions; and (iii) the “naive” substitution enables very easy the combination of the original KR-FMF with future's more accurate but potentially more complicated EOS of hard sphere mixtures.

  11. Asymmetrical phase separation and gelation in binary mixtures of oppositely charged colloids

    Science.gov (United States)

    Zong, Yiwu; Yuan, Guangcui; Han, Charles C.

    2016-07-01

    Two types of colloidal particles, which are nearly the same in chemical composition but carry opposite surface charges, are mixed in water. Depending on the relative proportion of the oppositely charged particles, the process of aggregation leads to the formation of discrete clusters of various sizes in dilute dispersions, and to the development of particle gel networks in more concentrated systems. Due to the significant difference in the absolute values of surface charges (negative particle: -48 mV, positive particle: +24 mV), the phase separation and the gelation behaviors are asymmetric with respect to the mixing ratio. Mixtures with excess negative particles are more stable, while mixtures with excess positive particles are easily affected by phase separation. The hetero-aggregation triggered by the addition of microscopically large macro-ions is similar to what is often observed in a mono-component charged colloidal system, i.e., phase separation occurs through addition of small electrolyte ions. Within the concentration region investigated here, it is clear that the gel line is buried inside the phase separation region. Gelation occurs only when the number and size of the clusters are large and big enough to connect up into a space-spanning network. Our results indicate that, in this binary mixture of oppositely charged colloids, although the interaction between unlike species is attractive and that between like species is repulsive, the onset of gelation is in fact governed by the equilibrium phase separation, as in the case of purely attractive systems with short-range isotropic interaction.

  12. Characterization of Dimethylsulfoxide / Glycerol Mixtures: A Binary Solvent System for the Study of "Friction-Dependent" Chemical Reactivity

    CERN Document Server

    Angulo, Gonzalo; Gerecke, Mario; Grampp, Günter; Jeannerat, Damien; Milkiewicz, Jadwiga; Mitrev, Yavor; Radzewicz, Czesław; Rosspeintner, Arnulf; Vauthey, Eric; Wnuk, Paweł

    2016-01-01

    The properties of binary mixtures of dimethylsulfoxide and glycerol, measured by several techniques, are reported. Special attention is given to those properties contributing or affecting chemical reactions. In this respect the investigated mixture behaves as a relatively simple solvent and it is especially well suited for studies on the influence of viscosity in chemical reactivity. This is due to the relative invariance of the dielectric properties of the mixture. However, special caution must be taken with specific solvation, as the hydrogen-bonding properties of the solvent changes with the molar fraction of glycerol.

  13. Adsorption of binary gas mixtures in heterogeneous carbon predicted by density functional theory: on the formation of adsorption azeotropes.

    Science.gov (United States)

    Ritter, James A; Pan, Huanhua; Balbuena, Perla B

    2010-09-07

    Classical density functional theory (DFT) was used to predict the adsorption of nine different binary gas mixtures in a heterogeneous BPL activated carbon with a known pore size distribution (PSD) and in single, homogeneous, slit-shaped carbon pores of different sizes. By comparing the heterogeneous results with those obtained from the ideal adsorbed solution theory and with those obtained in the homogeneous carbon, it was determined that adsorption nonideality and adsorption azeotropes are caused by the coupled effects of differences in the molecular size of the components in a gas mixture and only slight differences in the pore sizes of a heterogeneous adsorbent. For many binary gas mixtures, selectivity was found to be a strong function of pore size. As the width of a homogeneous pore increases slightly, the selectivity for two different sized adsorbates may change from being greater than unity to less than unity. This change in selectivity can be accompanied by the formation of an adsorption azeotrope when this same binary mixture is adsorbed in a heterogeneous adsorbent with a PSD, like in BPL activated carbon. These results also showed that the selectivity exhibited by a heterogeneous adsorbent can be dominated by a small number of pores that are very selective toward one of the components in the gas mixture, leading to adsorption azeotrope formation in extreme cases.

  14. Binary ionic porphyrin nanosheets: electronic and light-harvesting properties regulated by crystal structure

    Science.gov (United States)

    Tian, Yongming; M. Beavers, Christine; Busani, Tito; Martin, Kathleen E.; Jacobsen, John L.; Mercado, Brandon Q.; Swartzentruber, Brian S.; van Swol, Frank; Medforth, Craig J.; Shelnutt, John A.

    2012-02-01

    Crystalline solids self-assembled from anionic and cationic porphyrins provide a new class of multifunctional optoelectronic micro- and nanomaterials. A 1 : 1 combination of zinc(ii) tetra(4-sulfonatophenyl)porphyrin (ZnTPPS) and tin(iv) tetra(N-methyl-4-pyridiniumyl)porphyrin (SnTNMePyP) gives porphyrin nanosheets with high aspect ratios and varying thickness. The room temperature preparation of the nanosheets has provided the first X-ray crystal structure of a cooperative binary ionic (CBI) solid. The unit cell contains one and one-half molecules of aquo-ZnTPPS4- (an electron donor) and three half molecules of dihydroxy-SnTNMePyP4+ (an electron acceptor). Charge balance in the solid is reached without any non-porphyrinic ions, as previously determined for other CBI nanomaterials by non-crystallographic means. The crystal structure reveals a complicated molecular arrangement with slipped π-π stacking only occurring in isolated dimers of one of the symmetrically unique zinc porphyrins. Consistent with the crystal structure, UV-visible J-aggregate bands indicative of exciton delocalization and extended π-π stacking are not observed. XRD measurements show that the structure of the Zn/Sn nanosheets is distinct from that of Zn/Sn four-leaf clover-like CBI solids reported previously. In contrast with the Zn/Sn clovers that do exhibit J-aggregate bands and are photoconductive, the nanosheets are not photoconductive. Even so, the nanosheets act as light-harvesting structures in an artificial photosynthesis system capable of reducing water to hydrogen but not as efficiently as the Zn/Sn clovers.Crystalline solids self-assembled from anionic and cationic porphyrins provide a new class of multifunctional optoelectronic micro- and nanomaterials. A 1 : 1 combination of zinc(ii) tetra(4-sulfonatophenyl)porphyrin (ZnTPPS) and tin(iv) tetra(N-methyl-4-pyridiniumyl)porphyrin (SnTNMePyP) gives porphyrin nanosheets with high aspect ratios and varying thickness. The room

  15. Mechanism of graphene formation by graphite electro-exfoliation in ionic liquids-water mixtures

    Science.gov (United States)

    Xu, Junli; Shi, Zhongning; Zhang, Xia; Haarberg, Geir Martin

    2014-12-01

    Graphene was produced from graphite electrode by exfoliation in ionic liquid. The influences of process parameters such as ionic liquid concentration, electrolysis potential and the type of anions in the ionic liquid on the production of graphene were studied, and a new mechanism is proposed. The results show that the increase of ionic liquid concentration is beneficial for the formation of graphene, and it is easier to produce graphene by increasing the applied voltage. Ionic liquids anions have great effect on the production of graphene. Both graphite anode and graphite cathode can be modified to graphene during electrolysis. Gases formed inside of the electrode play an important role for the production of graphene, while ionic liquids serve to accelerate the switching rate of graphite to graphene.

  16. 混合制冷工质核态沸腾的传热研究%Heat transfer in nucleate pool boiling of binary and ternary refrigerant mixtures

    Institute of Scientific and Technical Information of China (English)

    赵耀华; 刁彦华; 鹤田隆治; 西川日出男

    2004-01-01

    Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants,HFC-134a,HFC-32,and HFC-125,their binary and ternary mixtures under saturated conditions at 0.9MPa.Compared to pure components,both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased.Experimental data were compared with some empirical and semi-empirical correlations available in literature.For binary mixture,the accuracy of the correlations varied considerably with mixtures and the heat flux.Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome.For ternary mixture,the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points,and their concentration difference had important effects on boiling heat transfer coefficients.

  17. Powder properties of binary mixtures of chloroquine phosphate with lactose and dicalcium phosphate

    Directory of Open Access Journals (Sweden)

    Michael Ayodele Odeniyi

    2010-09-01

    Full Text Available A study was conducted on the packing and cohesive properties of chloroquine phosphate in binary mixtures with lactose and dicalcium phosphate powders. The maximum volume reduction due to packing as expressed by the Kawakita constant, a, and the angle of internal flow, θ, were the assessment parameters. The individual powders were characterized for their particle size and shape using an optical microscope. Binary mixtures of various proportions of chloroquine phosphate with lactose and dicalcium phosphate powders were prepared. The bulk and tapped densities, angles of repose and internal flow, as well as compressibility index of the materials were determined using appropriate parameters. The calculated and determined values of maximum volume reduction for the binary mixtures were found to differ significantly (PRealizou-se estudo das propriedades de empacotamento e de coesão do fosfato de cloroquina em misturas binárias com lactose e fosfato dicálcico em pó. O volume máximo de redução devido ao empacotamento, segundo expresso pela constante de Kawakita, a, e o ângulo de fluxo interno, θ, foram os parâmetros de avaliação. Os pós individuais foram caracterizados por seu tamanho e forma de partículas, utilizando microscópio óptico. Prepararam-se misturas binárias de várias proporções de fosfato de cloroquine e lactose e fosfato dicálcico em pó. As densidades de bulk and tapped, os ângulos de repouso e de fluxo interno e o índice de compressibilidade dos materiais foram determinados utilizando-se parâmetros apropriados. Os valores calculados e determinados do volume máximo de redução para as misturas binárias mostraram-se significativamente diferentes (P< 0,05, sendo o traçado de Kawakita mais confiável na determinação das propriedades de empacotamento. O tipo de diluente influenciou as propriedades de fluxo das misturas com fosfato dicálcico, dando resultados previsíveis, enquanto as misturas contendo lactose

  18. High tenacity regenerated chitosan fibers prepared by using the binary ionic liquid solvent (Gly·HCl)-[Bmim]Cl.

    Science.gov (United States)

    Ma, Bomou; Qin, Aiwen; Li, Xiang; He, Chunju

    2013-09-12

    A binary ionic liquid system was confirmed to be a promising solvent to dissolve chitosan, and the regenerated chitosan fibers were prepared by wet and dry-wet spinning technique respectively. The SEM results show that the chitosan fibers prepared by wet spinning technique present striated surface and round cross section, and the chitosan fibers prepared by dry-wet spinning technique present smooth surface and irregular cross section. The mechanical testing results show that the regenerated chitosan fibers present relatively high tenacity, especially, these prepared by dry-wet spinning process present excellent strength and initial modulus, i.e. 2.1cN/dtex and 83.5cN/dtex, which is stronger than that of most reported chitosan fibers. The FT-IR results show that the dissolution of chitosan in the binary ionic liquid system is due to the protonation of NH₂ groups in the chitosan chains. Furthermore, a possible reaction during the dissolution and regeneration process is proposed.

  19. Ternary mixtures of ionic liquids for better salt solubility, conductivity and cation transference number improvement

    Science.gov (United States)

    Karpierz, E.; Niedzicki, L.; Trzeciak, T.; Zawadzki, M.; Dranka, M.; Zachara, J.; Żukowska, G. Z.; Bitner-Michalska, A.; Wieczorek, W.

    2016-01-01

    We hereby present the new class of ionic liquid systems in which lithium salt is introduced into the solution as a lithium cation−glyme solvate. This modification leads to the reorganisation of solution structure, which entails release of free mobile lithium cation solvate and hence leads to the significant enhancement of ionic conductivity and lithium cation transference numbers. This new approach in composing electrolytes also enables even three-fold increase of salt concentration in ionic liquids. PMID:27767069

  20. Ternary mixtures of ionic liquids for better salt solubility, conductivity and cation transference number improvement

    Science.gov (United States)

    Karpierz, E.; Niedzicki, L.; Trzeciak, T.; Zawadzki, M.; Dranka, M.; Zachara, J.; Żukowska, G. Z.; Bitner-Michalska, A.; Wieczorek, W.

    2016-10-01

    We hereby present the new class of ionic liquid systems in which lithium salt is introduced into the solution as a lithium cation-glyme solvate. This modification leads to the reorganisation of solution structure, which entails release of free mobile lithium cation solvate and hence leads to the significant enhancement of ionic conductivity and lithium cation transference numbers. This new approach in composing electrolytes also enables even three-fold increase of salt concentration in ionic liquids.

  1. Physiological response of the nematode Caenorhabditis elegans exposed to binary mixture of uranium and cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Margerit, A.; Gilbin, R. [French Institute for Radiological Protection and Nuclear Safety - IRSN (France); Gomez, E. [Universite Montpellier 1 (France)

    2014-07-01

    Both uranium (U) and cadmium (Cd) are natural ubiquitous substances whose occurrence may be magnified in the vicinity of some Nuclear Fuel Cycle Facility (NFCF) (e.g. uranium mining area) or intensive farming areas. Natural U is a mainly chemo-toxic radioelement, with a slight radio-toxic activity, while Cd is a fully chemo-toxic trace metal. Due to their possible co-occurrence, the study of their combined effects on ecosystems may be of interest in a risk assessment perspective. MixTox tool is a simple descriptive model commonly used to study the effects of chemical mixtures. It relies on dose response, concentration addition and response addition concepts to describe combined toxicant effects and identify possible Synergistic/Antagonistic - Constant/Dose-level/Dose ratio dependent - interactions. In the present study, toxicity of binary mixture of U and Cd was assessed on physiological parameters, maximal length and brood size, in the soil nematode Caenorhabditis elegans. A 49 condition fractional factorial design was used with U and Cd concentrations ranging from 0.95 to 1.3 mM and 0.006 to 0.04 mM, respectively. Dose response curves obtained for U and Cd on maximal length and brood size were consistent with published data. Using MixTox tool, the best description of these endpoints was met with the response addition concept and the dose-ratio dependent interaction model. A significant antagonism was identified when Cd toxicity is preponderant in the mixture and was confirmed with experimental observations. On the other hand, no significant interaction could be identified when U toxicity was preponderant in the mixture. Interaction between the two chemicals may occur during the exposure, the toxicokinetics and/or during the toxico-dynamic phases. Based on the results of this study, a probable hypothesis would be that U, whose toxicity is in the mM range, reduces bioaccumulation of Cd, whose toxicity is in the range of 10 μM. A bioaccumulation assay of U and Cd

  2. Soot modeling of counterflow diffusion flames of ethylene-based binary mixture fuels

    KAUST Repository

    Wang, Yu

    2015-03-01

    A soot model was developed based on the recently proposed PAH growth mechanism for C1-C4 gaseous fuels (KAUST PAH Mechanism 2, KM2) that included molecular growth up to coronene (A7) to simulate soot formation in counterflow diffusion flames of ethylene and its binary mixtures with methane, ethane and propane based on the method of moments. The soot model has 36 soot nucleation reactions from 8 PAH molecules including pyrene and larger PAHs. Soot surface growth reactions were based on a modified hydrogen-abstraction-acetylene-addition (HACA) mechanism in which CH3, C3H3 and C2H radicals were included in the hydrogen abstraction reactions in addition to H atoms. PAH condensation on soot particles was also considered. The experimentally measured profiles of soot volume fraction, number density, and particle size were well captured by the model for the baseline case of ethylene along with the cases involving mixtures of fuels. The simulation results, which were in qualitative agreement with the experimental data in the effects of binary fuel mixing on the sooting structures of the measured flames, showed in particular that 5% addition of propane (ethane) led to an increase in the soot volume fraction of the ethylene flame by 32% (6%), despite the fact that propane and ethane are less sooting fuels than is ethylene, which is in reasonable agreement with experiments of 37% (14%). The model revealed that with 5% addition of methane, there was an increase of 6% in the soot volume fraction. The average soot particle sizes were only minimally influenced while the soot number densities were increased by the fuel mixing. Further analysis of the numerical data indicated that the chemical cross-linking effect between ethylene and the dopant fuels resulted in an increase in PAH formation, which led to higher soot nucleation rates and therefore higher soot number densities. On the other hand, the rates of soot surface growth per unit surface area through the HACA mechanism were

  3. Rayleigh-Bénard convection in binary mixtures with separation ratios near zero

    Science.gov (United States)

    Dominguez-Lerma, Marco A.; Ahlers, Guenter; Cannell, David S.

    1995-12-01

    We present an experimental study of convection in binary mixtures with separation ratios Ψ close to zero. Measurements of the Hopf frequency for Ψmass concentration x with high precision. These results are consistent with but more precise than earlier measurements by conventional techniques. For Ψ>0, we found that the pattern close to onset consisted of squares. Our data give the threshold of convection rc≡Rc/Rc0 (Rc is the critical Rayleigh number of the mixture and Rc0 that of the pure fluid) from measurements of the refractive-index power of the pattern as revealed by a very sensitive quantitative shadowgraph method. Over the range Ψ~0.2, these results are in good agreement with linear stability analysis. The measured refractive-index power varies by six orders of magnitude as a function of r and for r>~0.55 is in reasonable agreement with predictions based on the ten-mode Lorenz-like Galerkin truncation of Müller and Lücke [H. W. Müller and M. Lücke, Phys. Rev. A 38, 2965 (1988)]. For smaller r, the model predicts a cancellation between contributions to the refractive index from concentration and temperature variations, which does not seem to occur in the physical system. Determinations of the wave numbers of the patterns near onset are consistent with the theoretically predicted small critical wave numbers at positive Ψ. As r approaches one, we find that q approaches the critical wave number qc0~=3 of the pure fluid. (c) 1995 The American Physical Society

  4. Dielectric relaxation of binary polar liquid mixture measured in benzene at 10 GHz frequency

    Indian Academy of Sciences (India)

    S Sahoo; K Dutta; S Acharyya; S K Sit

    2008-03-01

    The dielectric relaxation times 's and dipole moments 's of the binary () polar liquid mixture of N,N-dimethyl acetamide (DMA) and acetone (Ac) dissolved in benzene (i) are estimated from the measured real ′ and imaginary ″ parts of complex high frequency conductivity * of the solution for different weight fractions 's of 0.0, 0.3, 0.5, 0.7 and 1.0 mole fractions of Ac and temperatures (25, 30, 35 and 40°C) respectively under 9.88 GHz electric field. 's are obtained from the ratio of slopes of ″ - and ′ - curves at → 0 as well as linear slope of ″ - ′ curves of the existing method (Murthy et al, 1989) in order to eliminate polar-polar interaction in the latter case. The calculated 's are in excellent agreement with the reported 's due to Gopalakrishna's method. 's are also estimated from slopes 's of total conductivity - curves at → 0 and the values agree well with the reported 's from G.K. method. The variation of 's and 's with of Ac reveals that solute-solute molecular association occurs within 0.0-0.3 of Ac beyond which solute-solvent molecular association is predicted. The theoretical dipole moments theo's are calculated from bond angles and bond moments to have exact 's only to show the presence of inductive, mesomeric and electromeric effects in the substituent polar groups. The thermodynamic energy parameters are estimated from ln () against 1/ linear curve from Eyring's rate theory to know the molecular dynamics of the system and to establish the fact that the mixture obeys the Debye-Smyth relaxation mechanism.

  5. Five different spectrophotometric methods for determination of Amprolium hydrochloride and Ethopabate binary mixture

    Science.gov (United States)

    Hussein, Lobna A.; Magdy, N.; Abbas, Mahmoud M.

    2015-03-01

    Five simple, specific, accurate and precise UV-spectrophotometric methods are adopted for the simultaneous determination of Amprolium hydrochloride (AMP) and Ethopabate (ETH), a binary mixture with overlapping spectra, without preliminary separation. The first method is first derivative of the ratio spectra (1DD) for determination of AMP and ETH at 234.7 nm and 306.8 nm respectively with mean percentage recoveries 99.76 ± 0.907 and 100.29 ± 0.842 respectively. The second method is the mean centering of the ratio spectra for determination of AMP and ETH at 238.8 nm and 313 nm respectively with mean percentage recoveries 100.26 ± 1.018 and 99.94 ± 1.286 respectively. The third method is based on dual wavelength selection for determination of AMP and ETH at 235.3 nm & 308 nm and 244 nm & 268.4 nm respectively with mean percentage recoveries 99.30 ± 1.097 and 100.03 ± 1.065 respectively. The fourth method is ratio difference method for determination of AMP and ETH at 239 nm & 310 nm and 239 nm & 313 nm respectively with mean percentage recoveries 99.27 ± 0.892 and 100.40 ± 1.814 respectively. The fifth one is area under the curve (AUC) method where the areas between 235.6-243 nm and 268.3-275 nm are selected for determination of AMP and ETH with mean percentage recoveries 100.35 ± 1.031 and 100.39 ± 0.956 respectively. These methods are tested by analyzing synthetic mixtures of the two drugs and they are applied to their pharmaceutical veterinary preparation. Methods are validated according to the ICH guidelines and accuracy, precision and repeatability are found to be within the acceptable limit.

  6. A new secondary relaxation in the rigid and planar 1-methylindole: Evidence from binary mixture studies

    Science.gov (United States)

    Wang, Meng; Li, Xiangqian; Guo, Yuxing; Wu, Tao; Liu, Ying Dan; Ngai, K. L.; Wang, Li-Min

    2016-12-01

    Found in our recent dielectric study of a planar and rigid glass-former, 1-methylindole (1MID), is an unusual secondary relaxation unrelated in its dynamic properties to the structural α-relaxation. We speculated that it originates from the in-plane motion of the molecules, and the supposedly universal Johari-Goldstein (JG) β-relaxation with strong connection to the structural α-relaxation in rigid glass-formers is not resolved [X. Q. Li et al. J. Chem. Phys. 143, 104505 (2015)]. In this work, dielectric measurements are performed in binary mixtures of 1MID with two aromatics of weak polarity, ethylbenzene (EB) and triphenylethylene (TPE), in the highly viscous regimes near glass transition. EB and TPE have smaller and larger molecular sizes and glass transition temperatures Tg than 1MID, respectively. Strikingly, the results show that the resolved secondary relaxations of 1MID in the two mixtures share the same relaxation time and their temperature dependence as pure 1MID, independent of the mode and degree of dilution. The results indicate that the unusual secondary relaxation is not directly coupled with the α-relaxation, and support the in-plane-rotation interpretation of its origin. On the other hand, the supposedly universal and intermolecular JG β-relaxation coming from the out-of-plane motion of the planar molecule has weaker dielectric strength, and it cannot be resolved from the more intense in-plane-rotation secondary relaxation because the dipole moment of 1MID lies on the plane.

  7. Influence of Molecular Structure on the Ideality of Mixing in Micelles Formed in Binary Mixtures of Surface-Active Drugs.

    Science.gov (United States)

    Taboada; Attwood; Ruso; García; Sarmiento; Mosquera

    1999-08-15

    The influence of the structure of the hydrophobic group on the ideality of mixing in binary mixtures of surface active molecules has been investigated using combinations of amphiphilic penicillins. Critical concentrations (cc) of the binary mixtures of these anionic surfactants were determined by conductivity measurements as a function of the composition. The nonideality of mixing was evaluated using a regular solution approximation and expressed in terms of the interaction parameter, beta. Mixing in micelles formed in binary mixtures of the structurally similar penicillins cloxacillin, dicloxacillin, and flucloxacillin was ideal (beta = 0). In contrast, the combination of either cloxacillin or dicloxacillin with the penicillin nafcillin produced mixed micelles in which the mixing deviated from ideality (beta = +0.1 to +0.2). The positive values of beta for these systems indicated negative synergism between components of the mixtures that may be a consequence of the marked structural differences between the hydrophobic groups of these drugs. The composition of the mixed micelles was derived from the cc data by application of a theoretical treatment based on excess thermodynamic quantities. Copyright 1999 Academic Press.

  8. Study on the Interaction Coefficients in PR Equation with vdW Mixing Rules for HFC and HC Binary Mixtures

    Science.gov (United States)

    Chen, Jian-Xin; Hu, Peng; Chen, Ze-Shao

    2008-12-01

    The Peng-Robinson equation of state with the van der Waals mixing rules was used to correlate vapor-liquid equilibrium (VLE) data for HFC/HC, HFC/HFC, and HC/HC binary mixtures. The interaction parameter k ij was obtained for every binary mixture. It was assumed that k ij has contributions from the two components, and each component has its own constant contribution factor k i for the mixture, and the values of k ij indicate the degree in difference of properties between the two components. Therefore, the interaction parameters k ij is proposed as: k ij = k i - k j . The values of the mixing factor k i for Hydrofluorocarbons (HFCs) and Hydrocarbons (HCs), including propane, isobutane, n-butane, R23, R32, R125, R143a, R134a, R152a, R227ea R236fa, R236ea, and R245fa, were obtained by least-square fitting. In total, 39 refrigerant binary mixtures were analyzed on the basis of this method, and the results showed good agreement with experimental data. The overall average absolute deviations of pressure and vapor mole fraction are 1.3 % and 0.0089, respectively.

  9. Phase behaviors of binary mixtures composed of electron-rich and electron-poor triphenylene discotic liquid crystals

    Science.gov (United States)

    An, Lingling; Jing, Min; Xiao, Bo; Bai, Xiao-Yan; Zeng, Qing-Dao; Zhao, Ke-Qing

    2016-09-01

    Disk-like liquid crystals (DLCs) can self-assemble to ordered columnar mesophases and are intriguing one-dimensional organic semiconductors with high charge carrier mobility. To improve their applicable property of mesomorphic temperature ranges, we exploit the binary mixtures of electronic donor-acceptor DLC materials. The electron-rich 2,3,6,7,10,11-hexakis(alkoxy)triphenylenes (C4, C6, C8, C10, C12) and an electron-deficient tetrapentyl triphenylene-2,3,6,10-tetracarboxylate have been prepared and their binary mixtures have been investigated. The mesomorphism of the 1:1 (molar ratio) mixtures has been characterized by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and small angel x-ray scattering (SAXS). The self-assembled monolayer structure of a discogen on a solid-liquid interface has been imaged by the high resolution scanning tunneling microscopy (STM). The match of peripheral chain length has important influence on the mesomorphism of the binary mixtures. Project supported by the National Natural Science Foundation of China (Grant Nos. 51273133 and 51443004).

  10. Molecular dynamics simulations of the structure and single-particle dynamics of mixtures of divalent salts and ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-González, Víctor; Docampo-Álvarez, Borja; Gallego, Luis J.; Varela, Luis M., E-mail: luismiguel.varela@usc.es [Grupo de Nanomateriais e Materia Branda, Departamento de Física da Materia Condensada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela (Spain); Cabeza, Oscar [Facultade de Ciencias, Universidade da Coruña, Campus A Zapateira s/n, E-15008 A Coruña (Spain); Fedorov, Maxim [Department of Physics, Scottish University Physics Alliance (SUPA), University of Strathclyde, John Anderson Bldg., 107 Rottenrow East, Glasgow G4 0NG (United Kingdom); Lynden-Bell, Ruth M. [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2015-09-28

    We report a molecular dynamics study of the structure and single-particle dynamics of mixtures of a protic (ethylammonium nitrate) and an aprotic (1-butyl-3-methylimidazolium hexaflurophosphate [BMIM][PF{sub 6}]) room-temperature ionic liquids doped with magnesium and calcium salts with a common anion at 298.15 K and 1 atm. The solvation of these divalent cations in dense ionic environments is analyzed by means of apparent molar volumes of the mixtures, radial distribution functions, and coordination numbers. For the protic mixtures, the effect of salt concentration on the network of hydrogen bonds is also considered. Moreover, single-particle dynamics of the salt cations is studied by means of their velocity autocorrelation functions and vibrational densities of states, explicitly analyzing the influence of salt concentration, and cation charge and mass on these magnitudes. The effect of the valency of the salt cation on these properties is considered comparing the results with those for the corresponding mixtures with lithium salts. We found that the main structural and dynamic features of the local solvation of divalent cations in ionic liquids are similar to those of monovalent salts, with cations being localized in the polar nanoregions of the bulk mixture coordinated in monodentate and bidentate coordination modes by the [NO{sub 3}]{sup −} and [PF{sub 6}]{sup −} anions. However, stronger electrostatic correlations of these polar nanoregions than in mixtures with salts with monovalent cations are found. The vibrational modes of the ionic liquid (IL) are seen to be scarcely affected by the addition of the salt, and the effect of mass and charge on the vibrational densities of states of the dissolved cations is reported. Cation mass is seen to exert a deeper influence than charge on the low-frequency vibrational spectra, giving a red shift of the vibrational modes and a virtual suppression of the higher energy vibrational modes for the heavier Ca{sup 2

  11. Isotropic-nematic phase equilibria of hard-sphere chain fluids-Pure components and binary mixtures.

    Science.gov (United States)

    Oyarzún, Bernardo; van Westen, Thijs; Vlugt, Thijs J H

    2015-02-14

    The isotropic-nematic phase equilibria of linear hard-sphere chains and binary mixtures of them are obtained from Monte Carlo simulations. In addition, the infinite dilution solubility of hard spheres in the coexisting isotropic and nematic phases is determined. Phase equilibria calculations are performed in an expanded formulation of the Gibbs ensemble. This method allows us to carry out an extensive simulation study on the phase equilibria of pure linear chains with a length of 7 to 20 beads (7-mer to 20-mer), and binary mixtures of an 8-mer with a 14-, a 16-, and a 19-mer. The effect of molecular flexibility on the isotropic-nematic phase equilibria is assessed on the 8-mer+19-mer mixture by allowing one and two fully flexible beads at the end of the longest molecule. Results for binary mixtures are compared with the theoretical predictions of van Westen et al. [J. Chem. Phys. 140, 034504 (2014)]. Excellent agreement between theory and simulations is observed. The infinite dilution solubility of hard spheres in the hard-sphere fluids is obtained by the Widom test-particle insertion method. As in our previous work, on pure linear hard-sphere chains [B. Oyarzún, T. van Westen, and T. J. H. Vlugt, J. Chem. Phys. 138, 204905 (2013)], a linear relationship between relative infinite dilution solubility (relative to that of hard spheres in a hard-sphere fluid) and packing fraction is found. It is observed that binary mixtures greatly increase the solubility difference between coexisting isotropic and nematic phases compared to pure components.

  12. Efficiency enhancement of dye-sensitized solar cells with addition of additives (single/binary) to ionic liquid electrolyte

    Indian Academy of Sciences (India)

    H-S Lee; S-H Bae; C-H Han; S S Sekhon

    2012-11-01

    The effect of addition of single and binary additives on the performance of dye-sensitized TiO2 solar cells based on electrolytes containing an ionic liquid (IL), 1,2-dimethyl-3-propylimidazolium iodide (DMPII) has been studied. Among the seven additives used, the addition of 2-(dimethylamino)-pyridine (DMAP) to IL resulted in best cell efficiency, which showed further enhancement with the addition of 5-chloro-1-ethyl-2-methylimidazole (CEMI) as second additive. The efficiency of the dye-sensitized solar cell (DSC) based on an electrolyte containing binary additives (DMAP and CEMI in equal molar ratios) has been found to increase by 62.5% from 4.35 to 7.07%. The dependence of different photovoltaic performance parameters (\\oc, sc, , ) of DSC upon temperature has been studied over a 30–120°C range and only a small decrease in conversion efficiency has been observed. The electrolyte containing binary additives (DMAP and CEMI) shows best cell performance up to 120°C.

  13. Modeling vapor liquid equilibrium of ionic liquids + gas binary systems at high pressure with cubic equations of state

    Directory of Open Access Journals (Sweden)

    A. C. D. Freitas

    2013-03-01

    Full Text Available Ionic liquids (IL have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR and Soave-Redlich-Kwong (SRK equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (vdW-2. The experimental data were taken from the literature. The optimum binary interaction parameters were estimated by minimization of an objective function based on the average absolute relative deviation of liquid and vapor phases, using the modified Simplex algorithm. The solubilities of all gases studied in this work decrease as the temperature increases and increase with increasing pressure. The correlated results were highly satisfactory, with average absolute relative deviations of 2.10% and 2.25% for PR-vdW-2 and SRK-vdW-2, respectively.

  14. Thermochemistry of the dissolution and ion association of ionic liquids in isopropanol and isopropanol-water mixtures

    Science.gov (United States)

    Belov, A. V.; Solov'ev, S. N.; Artemkina, Yu. M.

    2015-07-01

    The enthalpies of dissolution of [C4mim]OTf, [C4mim]NTf2, and [C4mpy]NTf2 ionic liquids in isopropanol and isopropanol-water mixtures of three compositions are measured with an isothermal calorimeter at 298.15 K. The enthalpies of dilution of [C4mim]OTf solutions in an isopropanol-water mixture containing 50.0 mol % of alcohol are also determined. Enthalpies and constants of ion association are estimated and the standard enthalpies of dissolution are found for [C4mim]OTf, [C4mim]NTf2, and [C4mpy]NTf2 in isopropanol and its mixtures with water.

  15. Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C{sub 1}-C{sub 4}) and dimethyl carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Hiroyuki, E-mail: matsuda@chem.cst.nihon-u.ac.jp [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Fukano, Makoto; Kikkawa, Shinichiro [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Constantinescu, Dana [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany); Kurihara, Kiyofumi; Tochigi, Katsumi; Ochi, Kenji [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Gmehling, Juergen [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

    2012-01-15

    Highlights: > The VLE behavior of systems containing dimethyl carbonate (DMC) was investigated. > VLE data for ternary and binary mixtures containing alcohol and DMC were measured. > Several activity coefficient models were used for data reduction or prediction. > Valley line, i.e., distillation boundary, was observed for the ternary mixture. > Residue curves were calculated to investigate composition profile for distillation. - Abstract: (Vapor + liquid) equilibrium (VLE) data for a ternary mixture, namely {l_brace}methanol + propan-1-ol + dimethyl carbonate (DMC){r_brace}, and four binary mixtures, namely an {l_brace}alcohol (C{sub 3} or C{sub 4}) + DMC{r_brace}, containing the binary constituent mixtures of the ternary mixture, were measured at p = (40.00 to 93.32) kPa using a modified Swietoslawski-type ebulliometer. The experimental data for the binary systems were correlated using the Wilson model. The Wilson model was also applied to the ternary system to predict the VLE behavior using parameters from the binary mixtures. The modified UNIFAC (Dortmund) model was also tested for the predictions of the VLE behavior of the binary and ternary mixtures. In addition, the experimental VLE data for the ternary and constituent binary mixtures were correlated using the extended Redlich-Kister (ERK) model, which can completely represent the azeotropic points. For the ternary system, a comparison of the experimental and the predicted or correlated boiling points obtained using the Wilson and ERK models showed that the ERK model is more accurate. The valley line, i.e., the curve which divides the patterns of vapor-liquid tie lines, was found in the (methanol + propan-1-ol + DMC) system. This valley line could be represented by the ERK model. Finally, the composition profile for simple distillation of this ternary mixture was obtained by analysis of the residue curves from the estimated Wilson parameters of the constituent binary mixtures.

  16. Novel spectroscopic methods for determination of Cromolyn sodium and Oxymetazoline hydrochloride in binary mixture

    Science.gov (United States)

    Abdel-Aziz, Omar; El-Kosasy, A. M.; Magdy, N.; El Zahar, N. M.

    2014-10-01

    New accurate, sensitive and selective spectrophotometric and spectrofluorimetric methods were developed and subsequently validated for determination of Cromolyn sodium (CS) and Oxymetazoline HCl (OXY) in binary mixture. These methods include ‘H-point standard addition method (HPSAM) and area under the curve (AUC)' spectrophotometric method and first derivative synchronous fluorescence spectroscopic (FDSFS) method. For spectrophotometric methods, absorbances were recorded at 241.5 nm and 274.9 nm for HPSAM and the wavelength was selected in ranges 232.0-254.0 nm and 216.0-229.0 nm for AUC method, where the concentration was obtained by applying Cramer's rule. For FDSFS method, the first-derivative synchronous fluorescence signal was measured at 290.0 nm, using Δλ = 145.0 nm. The suggested methods were validated according to International Conference of Harmonization (ICH) guidelines and the results revealed that they were precise and reproducible. All the obtained results were statistically compared with those of the reported method and there was no significant difference.

  17. Density functional theory of gas-liquid phase separation in dilute binary mixtures.

    Science.gov (United States)

    Okamoto, Ryuichi; Onuki, Akira

    2016-06-22

    We examine statics and dynamics of phase-separated states of dilute binary mixtures using density functional theory. In our systems, the difference of the solvation chemical potential between liquid and gas [Formula: see text] (the Gibbs energy of transfer) is considerably larger than the thermal energy [Formula: see text] for each solute particle and the attractive interaction among the solute particles is weaker than that among the solvent particles. In these conditions, the saturated vapor pressure increases by [Formula: see text], where [Formula: see text] is the solute density added in liquid. For [Formula: see text], phase separation is induced at low solute densities in liquid and the new phase remains in gaseous states, even when the liquid pressure is outside the coexistence curve of the solvent. This explains the widely observed formation of stable nanobubbles in ambient water with a dissolved gas. We calculate the density and stress profiles across planar and spherical interfaces, where the surface tension decreases with increasing interfacial solute adsorption. We realize stable solute-rich bubbles with radius about 30 nm, which minimize the free energy functional. We then study dynamics around such a bubble after a decompression of the surrounding liquid, where the bubble undergoes a damped oscillation. In addition, we present some exact and approximate expressions for the surface tension and the interfacial stress tensor.

  18. Benchmark solutions for transport in d-dimensional Markov binary mixtures

    Science.gov (United States)

    Larmier, Coline; Hugot, François-Xavier; Malvagi, Fausto; Mazzolo, Alain; Zoia, Andrea

    2017-03-01

    Linear particle transport in stochastic media is key to such relevant applications as neutron diffusion in randomly mixed immiscible materials, light propagation through engineered optical materials, and inertial confinement fusion, only to name a few. We extend the pioneering work by Adams, Larsen and Pomraning [1] (recently revisited by Brantley [2]) by considering a series of benchmark configurations for mono-energetic and isotropic transport through Markov binary mixtures in dimension d. The stochastic media are generated by resorting to Poisson random tessellations in 1 d slab, 2 d extruded, and full 3 d geometry. For each realization, particle transport is performed by resorting to the Monte Carlo simulation. The distributions of the transmission and reflection coefficients on the free surfaces of the geometry are subsequently estimated, and the average values over the ensemble of realizations are computed. Reference solutions for the benchmark have never been provided before for two- and three-dimensional Poisson tessellations, and the results presented in this paper might thus be useful in order to validate fast but approximated models for particle transport in Markov stochastic media, such as the celebrated Chord Length Sampling algorithm.

  19. Evaporation dynamics of non-spherical sessile drops of pure fluids and binary mixtures

    Science.gov (United States)

    Saenz, Pedro J.; Matar, Omar K.; Sefiane, Khellil; Valluri, Prashant; Kim, Jungho

    2015-11-01

    The dynamics of pure axisymmetric volatile sessile droplets have been meticulously examined over the last four decades but remain poorly understood. Studies focusing on more realistic non-spherical configurations are virtually non-existent. The dynamics of the latter are examined in this investigation by means of experiments and numerical simulations. We show that the lifetime and bulk flow characteristics of these drops depend on their size and shape. The irregular geometries lead to the emergence preferential convection currents in the liquid as well as differential local evaporation rates noticeable along the contact line. Similarly, we inspect the thermocapillary stability of the flow, which results as the liquid volatility increases, and find that this is also affected by the non-uniform wettability along the triple line. The Marangoni-driven instabilities grow in an intricate spatio-temporal fashion leading to the emergence of different flow regimes. Finally, we also provide new insights into the evaporation process of binary-mixture drops. Memphis Multiphase (EPSRC EP/K003976/1) & ThermaPOWER (EU IRSES-PIRSES GA-2011-294905).

  20. Thermal conductivity, shear and bulk viscosities for a relativistic binary mixture

    Science.gov (United States)

    Moratto, Valdemar; Kremer, Gilberto M.

    2016-11-01

    In the present work, we deal with a binary mixture of diluted relativistic gases within the framework of the kinetic theory. The analysis is made within the framework of the Boltzmann equation. We assume that the gas is under the influence of an isotropic Schwarzschild metric and is composed of particles with speeds comparable with the light speed. Taking into account the constitutive equations for the laws of Fourier and Navier-Stokes, we obtain expressions for the thermal conductivity, the shear, and bulk viscosities. To evaluate the integrals we assume a hard-sphere interaction along with non-disparate masses for the particles of each component. We show the analytical expressions and the behavior of the transport coefficients with respect to a relativistic parameter which gives the ratio of the rest energy of the particles to the thermal energy of the gas. We also determine the dependence of the transport coefficients with respect to the gravitational potential and demonstrate that the corresponding one component limit is recovered by considering particles with equal masses, in accordance with the kinetic theory of a single fluid.

  1. Parametric study on phase separation of binary mixtures in a lid driven cavity: A DPD study

    Science.gov (United States)

    Gidituri, Harinadha; Anand, Vijay; Panchagnula, Mahesh; Vedantam, Srikanth

    2016-11-01

    We investigate the phase separation behavior of binary mixtures in two dimensional periodic and lid driven cavity domains using dissipative particle dynamics (DPD). The effect of DPD parameters like repulsion coefficient, dissipative coefficient, cut-off radius, and weight function exponent on domain size growth has been studied. The phase separation is delayed for low values of repulsion coefficient. Under these conditions, a few clusters of the dispersed phase are distributed in a continuous phase. This is because of weak inter-particle repulsion. As we increase the repulsion coefficient value, this behavior disappears. The domain growth rate is also observed to increase with an increase in the value of the dissipation coefficient as well as cut-off radius. Finally, the dynamics of phase separation in the lid driven cavity problem are significantly different when compared to that in the periodic domain, due to the formation of a stable vortex in the cavity. The vortex results in a dynamic equilibrium between clustering and separation. The distribution of cluster sizes is studied as a function of the driven cavity parameters.

  2. Application of normalized spectra in resolving a challenging Orphenadrine and Paracetamol binary mixture

    Science.gov (United States)

    Yehia, Ali M.; Abd El-Rahman, Mohamed K.

    2015-03-01

    Normalized spectra have a great power in resolving spectral overlap of challenging Orphenadrine (ORP) and Paracetamol (PAR) binary mixture, four smart techniques utilizing the normalized spectra were used in this work, namely, amplitude modulation (AM), simultaneous area ratio subtraction (SARS), simultaneous derivative spectrophotometry (S1DD) and ratio H-point standard addition method (RHPSAM). In AM, peak amplitude at 221.6 nm of the division spectra was measured for both ORP and PAR determination, while in SARS, concentration of ORP was determined using the area under the curve from 215 nm to 222 nm of the regenerated ORP zero order absorption spectra, in S1DD, concentration of ORP was determined using the peak amplitude at 224 nm of the first derivative ratio spectra. PAR concentration was determined directly at 288 nm in the division spectra obtained during the manipulation steps in the previous three methods. The last RHPSAM is a dual wavelength method in which two calibrations were plotted at 216 nm and 226 nm. RH point is the intersection of the two calibration lines, where ORP and PAR concentrations were directly determined from coordinates of RH point. The proposed methods were applied successfully for the determination of ORP and PAR in their dosage form.

  3. Validation of different spectrophotometric methods for determination of vildagliptin and metformin in binary mixture

    Science.gov (United States)

    Abdel-Ghany, Maha F.; Abdel-Aziz, Omar; Ayad, Miriam F.; Tadros, Mariam M.

    New, simple, specific, accurate, precise and reproducible spectrophotometric methods have been developed and subsequently validated for determination of vildagliptin (VLG) and metformin (MET) in binary mixture. Zero order spectrophotometric method was the first method used for determination of MET in the range of 2-12 μg mL-1 by measuring the absorbance at 237.6 nm. The second method was derivative spectrophotometric technique; utilized for determination of MET at 247.4 nm, in the range of 1-12 μg mL-1. Derivative ratio spectrophotometric method was the third technique; used for determination of VLG in the range of 4-24 μg mL-1 at 265.8 nm. Fourth and fifth methods adopted for determination of VLG in the range of 4-24 μg mL-1; were ratio subtraction and mean centering spectrophotometric methods, respectively. All the results were statistically compared with the reported methods, using one-way analysis of variance (ANOVA). The developed methods were satisfactorily applied to analysis of the investigated drugs and proved to be specific and accurate for quality control of them in pharmaceutical dosage forms.

  4. ThermoData Engine (TDE): software implementation of the dynamic data evaluation concept. 3. Binary mixtures.

    Science.gov (United States)

    Diky, Vladimir; Chirico, Robert D; Kazakov, Andrei F; Muzny, Chris D; Frenkel, Michael

    2009-02-01

    ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported recently in this journal. The present paper describes the first application of this concept to the evaluation of thermophysical properties for binary chemical systems. Five activity-coefficient models have been implemented for representation of phase-equilibrium data (vapor-liquid, liquid-liquid, and solid-liquid equilibrium): NRTL, UNIQUAC, Van Laar, Margules/Redlich-Kister, and Wilson. Implementation of these models in TDE is fully described. Properties modeled individually are densities, surface tensions, critical temperatures, critical pressures, excess enthalpies, and the transport properties-viscosity and thermal conductivity. Extensions to the class structure of the program are described with emphasis on special features allowing close linkage between mixture and pure-component properties required for implementation of the models. Details of gas-phase models used in conjunction with the activity-coefficient models are shown. Initial implementation of the dynamic data evaluation concept for reactions is demonstrated with evaluation of enthalpies of formation for compounds containing carbon, hydrogen, oxygen, and nitrogen. Directions for future enhancements are outlined.

  5. Large heat capacity anomaly near the consolute point of the binary mixture nitromethane and 3-pentanol

    Science.gov (United States)

    Losada-Pérez, Patricia; Tripathi, Chandra Shekhar Pati; Leys, Jan; Glorieux, Christ; Thoen, Jan

    2011-01-01

    The large critical anomaly in the isobaric heat capacity C_{p,x}(T) of the binary mixture nitromethane + 3-pentanol is measured using high-resolution adiabatic scanning calorimetry. The unique features of this technique provided an alternative approach to the study of the critical behavior of C_{p,x}(T), providing further C_{p,x}(T) related quantities from which valuable information could be extracted. Our data are in full agreement with the predictions of the Modern Theory of Critical Phenomena; specifically, 3D-Ising model values for the critical exponent α and the universal amplitude ratio values of the leading critical amplitudes, as well as for the first correction-to-scaling ones, provide the optimum fits to represent the experimental data. Evidence for the need of higher-order terms, i.e., first correction-to-scaling term, is given. The large value of the coefficient E for the linear temperature dependence of the background obtained is ascribed to a possible contribution of the regular linear background term, of a higher-order asymmetry term, and of the second correction-to-scaling term. Internal consistency of C_{p,x}(T) and its related quantities is successfully checked.

  6. Evaluation of MidIR fibre optic reflectance: detection limit, reproducibility and binary mixture discrimination.

    Science.gov (United States)

    Sessa, Clarimma; Bagán, Héctor; García, José Francisco

    2013-11-01

    algorithm, polynomial baseline offset, Standard Normal Variate algorithm - SNV) to the raw spectra allows improving these results to maximum values of 15%. Finally, the capabilities of PCA and MidIR-FORS to discriminate between binary mixtures were tested. The results demonstrate that it is possible to differentiate mixtures depending on the range of concentration of their components, within specific limits of detection.

  7. Volumetric, Ultrasonic and Transport Properties of Binary Liquid Mixtures Containing Dimethyl Formamide at 303.15 K

    Institute of Scientific and Technical Information of China (English)

    SYAMALA,Vardhana; RAJA SEKHAR,Damaramadugu; SIVA KUMAR,Kasibhatta; VENKATESWARLU,Ponneri

    2007-01-01

    Excess volumes (VE), ultrasonic velocities (u), isentropic compressibility (△Ks) and viscosities (η) for the binary mixtures of dimethyl formamide (DMF) with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene,o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied.Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility (Ks) has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic compressibility (△Ks) from ideal behavior was also calculated. △Ks values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory (FLT) and Collision Factor Theory (CFT). The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules.

  8. Excess volumes of binary mixtures of 1,3-dichloropropane with isomeric butanols at 298. 15 and 313. 15 K

    Energy Technology Data Exchange (ETDEWEB)

    Lafuente, C.; Pardo, J.; Rodriguez, V.; Royo, F.M.; Urieta, J.S. (Univ. de Zargoza (Spain). Dept. de Quimica Organica-Quimica Fisica)

    1993-10-01

    Excess molar volumes, V[sub m][sup E], for binary mixtures of 1,3-dichloropropane with 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol have been determined from density measurements at 298.15 and 313.15 K by means of an Anton Paar DMA-58 vibrating tube densimeter. V[sub m][sup E] is positive over the whole composition range except for mixtures containing 1-butanol and 2-methyl-1-propanol at 298.15 K in which V[sub m][sup E] shows negative values at low mole fractions of dichloroalkane.

  9. Comparative study on the selectivity of various spectrophotometric techniques for the determination of binary mixture of fenbendazole and rafoxanide.

    Science.gov (United States)

    Saad, Ahmed S; Attia, Ali K; Alaraki, Manal S; Elzanfaly, Eman S

    2015-11-05

    Five different spectrophotometric methods were applied for simultaneous determination of fenbendazole and rafoxanide in their binary mixture; namely first derivative, derivative ratio, ratio difference, dual wavelength and H-point standard addition spectrophotometric methods. Different factors affecting each of the applied spectrophotometric methods were studied and the selectivity of the applied methods was compared. The applied methods were validated as per the ICH guidelines and good accuracy; specificity and precision were proven within the concentration range of 5-50 μg/mL for both drugs. Statistical analysis using one-way ANOVA proved no significant differences among the proposed methods for the determination of the two drugs. The proposed methods successfully determined both drugs in laboratory prepared and commercially available binary mixtures, and were found applicable for the routine analysis in quality control laboratories.

  10. Binary mixtures of rod-like colloids under shear: microscopically-based equilibrium theory and order-parameter dynamics.

    Science.gov (United States)

    Lugo-Frías, Rodrigo; Klapp, Sabine H L

    2016-06-22

    This paper is concerned with the dynamics of a binary mixture of rod-like, repulsive colloidal particles driven out of equilibrium by means of a steady shear flow (Couette geometry). To this end we first derive, starting from a microscopic density functional in Parsons-Lee approximation, a mesoscopic free energy functional whose main variables are the orientational order parameter tensors. Based on this mesoscopic functional we then explore the stability of isotropic and nematic equilibrium phases in terms of composition and rod lengths. Second, by combining the equilibrium theory with the Doi-Hess approach for the order parameter dynamics under shear, we investigate the orientational dynamics of binary mixtures for a range of shear rates and coupling parameters. We find a variety of dynamical states, including synchronized oscillatory states of the two components, but also symmetry breaking behavior where the components display different in-plane oscillatory states.

  11. Parametrization of coarse grained force fields for dynamic property of ethylene glycol oligomers/water binary mixtures

    CERN Document Server

    Yamazaki, Tamio

    2011-01-01

    To evaluate shear viscosity of ehylene glycol oligomers (EGO)/water binary mixture by means of coarse-grained molecular dynamics (CG-MD) simulations, we proposed the self-diffusion-coefficient-based parameterization of non-bonded interactions among CG particles. Our parameterization procedure consists of three steps: 1)determination of bonded potentials, 2)scaling for time and solvent diffusivity, and 3)optimization of Lennard-Jones parameters to reproduce experimental self-diffusion coefficient data. With the determined parameters and the scaling relations, we evaluated shear viscosities of EGO/water binary mixtures, which are in close agreement with the experimental data, without any further fitting procedure. The largest simulation in this article corresponds to a 1.2 microseconds atomistic simulation for 100,000 atoms. Our CG model with the parameterization scheme for CG particles may be useful to study the dynamic properties of a liquid which contains relatively low molecular weight polymers or oligomers...

  12. Partial molar volumes of aluminium chloride, aluminium sulphate and aluminium nitrate in water-rich binary aqueous mixtures of tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    R. C. Thakur

    2014-12-01

    Full Text Available Partial molar volumes of aluminium chloride, aluminium sulphate and aluminium nitrate have been determined in water rich binary aqueous mixtures of tetrahydrofuran (5, 10, 15, 20% by weight of tetrahydrofuran with the help of density measurements. The density measurements were made by using Ward and Millero method and results have been analysed by Masson’s equation and interpreted in terms of ion-ion or ion –solvent interactions. The partial molar volumes vary with temperature as a power series of temperature. Structure making or breaking capacities of aluminium salts have been inferred from the sign à2/ Φvo p i.e second derivative of partial molar volume with respect to temperature at constant pressure. The aluminium salts have been found as structure breakers in binary aqueous mixture of tetrahydrofuran.

  13. Viscosities of oxalic acid and its salts in water and binary aqueous mixtures of tetrahydrofuran at different temperatures

    Indian Academy of Sciences (India)

    M L Parmar; M K Guleria

    2005-07-01

    Relative viscosities for the solutions of oxalic acid and its salts, viz. ammonium oxalate, sodium oxalate and potassium oxalate, at different concentrations have been determined in water and in binary aqueous mixtures of tetrahydrofuran (THF) [5, 10, 15 and 20% by weight of THF] at 298.15 K, and in water and in 5% (w/w) THF + water at five different temperatures. The data have been evaluated using the Jones-Dole equation and the obtained parameters have been interpreted in terms of solute-solute and solute-solvent interactions. The activation parameters of viscous flow have been obtained which depicts the mechanism of viscous flow. The oxalic acid and its salts behave as structure breakers in water and in binary aqueous mixtures of THF.

  14. Molecular dynamics simulation of the behaviour of water in nano-confined ionic liquid-water mixtures

    Science.gov (United States)

    Docampo-Álvarez, B.; Gómez-González, V.; Montes-Campos, H.; Otero-Mato, J. M.; Méndez-Morales, T.; Cabeza, O.; Gallego, L. J.; Lynden-Bell, R. M.; Ivaništšev, V. B.; Fedorov, M. V.; Varela, L. M.

    2016-11-01

    This work describes the behaviour of water molecules in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under nanoconfinement, between graphene sheets. By means of molecular dynamics simulations, the adsorption of water molecules at the graphene surface is studied. A depletion of water molecules in the vicinity of the neutral and negatively charged graphene surfaces, and their adsorption at the positively charged surface are observed in line with the preferential hydration of the ionic liquid anions. The findings are appropriately described using a two-level statistical model. The confinement effect on the structure and dynamics of the mixtures is thoroughly analyzed using the density and the potential of mean force profiles, as well as by the vibrational densities of the states of water molecules near the graphene surface. The orientation of water molecules and the water-induced structural transitions in the layer closest to the graphene surface are also discussed.

  15. Low-pressure equilibrium binary argon-methane gas mixture adsorption on exfoliated graphite: Experiments and simulations

    Science.gov (United States)

    Albesa, Alberto; Russell, Brice; Vicente, José Luis; Rafti, Matías

    2016-04-01

    Adsorption equilibrium measurements of pure methane, pure argon, and binary mixtures over exfoliated graphite were carried for different initial compositions, temperatures, and total pressures in the range of 0.1-1.5 Torr using the volumetric static method. Diagrams for gas and adsorbed phase compositions were constructed for the conditions explored, and isosteric heats of adsorption were calculated. Experimental results were compared with predictions obtained with Monte Carlo simulations and using the Ideal Adsorbed Solution Theory (IAST).

  16. The Solubility Parameters of Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Andrzej Marciniak

    2010-04-01

    Full Text Available The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

  17. A comparative study of room temperature ionic liquids and their organic solvent mixtures near charged electrodes

    Science.gov (United States)

    Vatamanu, Jenel; Vatamanu, Mihaela; Borodin, Oleg; Bedrov, Dmitry

    2016-11-01

    The structural properties of electrolytes consisting of solutions of ionic liquids in a polar solvent at charged electrode surfaces are investigated using classical atomistic simulations. The studied electrolytes consisted of tetraethylammonium tetrafluoroborate (NEt4-BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (c2mim-BF4) and 1-octyl-3-methylimidazolium tetrafluoroborate (c8mim-BF4) salts dissolved in acetonitrile solvent. We discuss the influence of electrolyte concentration, chemical structure of the ionic salt, temperature, conducting versus semiconducting nature of the electrode, electrode geometry and surface roughness on the electric double layer structure and capacitance and compare these properties with those obtained for pure room temperature ionic liquids. We show that electrolytes consisting of solutions of ions can behave quite differently from pure ionic liquid electrolytes.

  18. On the collective network of ionic liquid/water mixtures. III. Structural analysis of ionic liquids on the basis of Voronoi decomposition.

    Science.gov (United States)

    Schröder, C; Neumayr, G; Steinhauser, O

    2009-05-21

    Three different mixtures of 1-butyl-3-methyl-imidazolium tetrafluoroborate with water have been studied by means of molecular dynamics simulations. Based on the classical Lopes-Padua force field trajectories of approximately 60 ns were computed. This is the third part of a series concerning the collective network of 1-butyl-3-methyl-imidazolium tetrafluoroborate/water mixtures. The first part [C. Schröder et al., J. Chem. Phys. 127, 234503 (2007)] dealt with the orientational structure and static dielectric constants. The second part [C. Schröder et al., J. Chem. Phys. 129, 184501 (2008)] was focused on the decomposition of the dielectric spectrum of these mixtures. In this work the focus lies on the characterization of the neighborhood of ionic liquids by means of the Voronoi decomposition. The Voronoi algorithm is a rational tool to uniquely decompose the space around a reference molecule without using any empirical parameters. Thus, neighborhood relations, direct and indirect ones, can be extracted and were used in combination with g-coefficients. These coefficients represent the generalization of the traditional radial distribution function in order to include the mutual positioning and orientation of anisotropic molecules. Furthermore, the Voronoi method provides, as a by-product, the mutual coordination numbers of molecular species.

  19. Comparative Study of the Intermolecular Dynamics of Benzene/Ionic Liquid Mixtures and Benzyl Functionalized Ionic Liquids: Femtosecond OKE Spectroscopic Measurements

    Science.gov (United States)

    Quitevis, Edward; Xue, Lianjie; Tamas, George

    2014-03-01

    Ionic liquids (ILs) are salts with melting points below 100 °C that are comprised of an organic cation and an inorganic or organic anion. There is great interest in obtaining a molecular level understanding of their unique physical and chemical properties, of which one of them is their ability, despite being inherently polar liquids, to dissolve large quantities of nonpolar aromatic compounds. In order to understand further the solvation of aromatic molecules in ILs, we have performed optical effect (OKE) spectroscopic measurements on 1-benzyl-3-methylimidazolum bistriflate, 1,3-dibenzylimidazolum bistriflate and the corresponding 1:1 and 2:1 benzene/1,3-dimethylimazolium bistrifate (C6H6/C1C1) mixtures. In contrast to being free in benzene/IL mixtures, the benzene rings are tethered to the imidazolium ring via methylene linkages in the case of first two ILs. The intermolecular Kerr spectra indicate that the motion of the benzene rings becomes increasingly more restricted in going from neat benzene to benzene dissolved in 1,3-dimethylimazolium bistrifate to benzene rings tethered to the imidazolium ring. This restriction causes the Kerr spectra effectively to shift to higher frequency in going from neat liquid benzene to C6H6/C1C1 mixtures to benzylimidazolium ILs. This work was supported by NSF Grant CHE-1153077.

  20. Molecular dynamics and a spectroscopic study of sulfur dioxide absorption by an ionic liquid and its mixtures with PEO.

    Science.gov (United States)

    Hoher, Karina; Cardoso, Piercarlo F; Lepre, Luiz F; Ando, Rômulo A; Siqueira, Leonardo J A

    2016-10-19

    An investigation comprising experimental techniques (absorption capacity of SO2 and vibrational spectroscopy) and molecular simulations (thermodynamics, structure, and dynamics) has been performed for the polymer poly(ethylene oxide) (PEO), the ionic liquid butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N4111][Tf2N]) and their mixtures as sulfur dioxide (SO2) absorbing materials. The polymer PEO has higher capacity to absorb SO2 than the neat ionic liquid, whereas the mixtures presented intermediary absorption capacities. The band assigned to the symmetric stretching band of SO2 at ca. 1140 cm(-1), which is considered a spectroscopic probe for the strength of SO2 interactions with its neighborhood, shifts to lower wavenumbers as more negative total interaction energy values of SO2 were evaluated from the simulations. The solvation free energy of SO2, ΔGsol, correlates linearly with the absorption capacity of SO2. The negative values of ΔGsol are due to negative and positive values of enthalpy and entropy, respectively. In the ionic liquid, SO2 weakens the cation-anion interactions, whereas in the mixture with a high content of PEO these interactions are slightly increased. Such effects were correlated with the relative population of cisoid and transoid conformers of Tf2N anions as revealed by Raman spectroscopy. Moreover, the presence of SO2 in the systems provokes the increase of diffusion coefficients of the absorbing species in comparison with the systems without the gas. Proper to the slow dynamics of the polymer, the diffusion coefficient of ions and SO2 diminishes with the increase of the PEO content.

  1. Thermodynamic properties of binary mixtures containing dimethyl carbonate+2-alkanol: Experimental data, correlation and prediction by ERAS model and cubic EOS

    Energy Technology Data Exchange (ETDEWEB)

    Almasi, Mohammad, E-mail: m.almasi@khouzestan.srbiau.ac.ir [Department of Chemistry, Science and Research Branch, Islamic Azad University, Khouzestan (Iran, Islamic Republic of)

    2013-03-01

    Densities and viscosities for binary mixtures of dimethyl carbonate with 2-propanol up to 2-heptanol were measured at various temperatures and ambient pressure. From experimental data, excess molar volumes, V{sub m}{sup E}. were calculated and correlated by the Redlich–Kister equation to obtain the binary coefficients and the standard deviations. Excess molar volumes, V{sub m}{sup E}, are positive for all studied mixtures over the entire range of the mole fraction. The ERAS-model has been applied for describing the binary excess molar volumes and also Peng–Robinson–Stryjek–Vera (PRSV) equation of state (EOS) has been used to predict the binary excess molar volumes and viscosities. Also several semi-empirical models were used to correlate the viscosity of binary mixtures.

  2. Partitioning regularity of non-ionic organic mixtures in organic phase/water system

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The partitioning regularity of nonionic organic mixtures in organic phase/water system is revealed. The equation for calculating the partition coefficients of mixtures (KMD), together with the determination model, is derived from the equilibrium partitioning models (EPMs). Based on these derived equations, the KMD values of 20 mixtures conraining halogenated benzenes are obtained. The results show that stronger hydrophobicity of an individual chemical in the mixture results in the stronger hydrophobicity of the mixture and the greater the proportion of this chemical, the stronger the hydrophobicity of the mixture will be. This partitioning regularity is helpful to the study of the toxicity for mixtures and the environmental behavior, such as transfer or accumuiation, for mixed organic pollutants.``

  3. Binary and Tertiary Mixtures of Satureja hortensis and Origanum vulgare Essential Oils as Potent Antimicrobial Agents Against Helicobacter pylori.

    Science.gov (United States)

    Lesjak, Marija; Simin, Natasa; Orcic, Dejan; Franciskovic, Marina; Knezevic, Petar; Beara, Ivana; Aleksic, Verica; Svircev, Emilija; Buzas, Krisztina; Mimica-Dukic, Neda

    2016-03-01

    Essential oils possess strong antimicrobial activity, even against multiresistant Helicobacter pylori. Available therapies against H. pylori infection have multiple disadvantages, indicating a great need for a development of new therapeutics. The purpose of this study was to develop a potent natural product based anti-H. pylori formulation. First, anti-H. pylori activity of nine essential oils was determined, after which the most active oils were mixed in various ratios for further testing. Satureja hortensis, Origanum vulgare subsp. vulgare and O. vulgare subsp. hirtum essential oils expressed the highest activity (MIC = 2 μL mL(-1)). Their binary and ternary mixtures exhibited notably higher antimicrobial activity (MIC ≤ 2 μL mL(-1)). The most active was the mixture of S. hortensis and O. vulgare subsp. hirtum oils in volume ratio 2:1, which expressed 4 times higher activity than individual oils (MIC = 0.5 μL mL(-1)). According to GC-MS, both oils in the mixture were characterized by high content of phenols (48-73%), with carvacrol as the main carrier of antimicrobial activity. Presented in vitro study pointed out binary mixture of S. hortensis and O. vulgare subsp. hirtum essential oils in volume ratio 2:1 as promising candidate for further in vivo studies targeting H. pylori infection.

  4. THE MIXTURES OF 2.4-DINITROPHENYLHIDRAZONES OF INFERIOR CARBONYL COMPOUNDS AND THEIR HPLC SEPARATION WITH GRADIENT BINARY MIXTURES PHASES

    Directory of Open Access Journals (Sweden)

    Gheorghe Zgherea

    2008-06-01

    Full Text Available Mixtures of small quantities of carbonyl compounds are presents in foods, concerning sensorial qualities. The inferior carbonyl compounds (C2-C4, boiling point <100°C – mono and dicarbonyl – can be identified and measured their concentrations, after a separation by distillation on the water bath. They are transferred in a strongly acid solution of 2.4-dinitrophenylhidrazine (2.4-DNPH, generating a mixture of insoluble 2.4-dinitrophenylhidrazones (2.4-DNPH-ones. The 2.4-DNPH-ones are organic compounds with weak polarity, solids, crystallized, yellows and water insoluble, soluble in organic solvents. The mixture of 2.4dinitrophenylhidrazones may be separated by liquid chromatography, using the reverse phase mechanism [1-3]. This paper contains experimental and theoretical considerations to the means of separation through liquid chromatography of two synthetically and a natural mixtures that contain 2.4-DNPH-ones provided by inferior carbonyl compounds; to obtain conclude results, in the synthetically mixtures was introduce and 2.4-DNPH-ones provided by carbonyl compounds having three (acetone and propanal and four (isobutyl aldehyde atoms of carbon.

  5. Studies on intermolecular interaction on binary mixtures of methyl orange-water system: excess molar functions of ultrasonic parameters at different concentrations and at different temperatures.

    Science.gov (United States)

    Thanuja, B; Kanagam, Charles; Sreedevi, S

    2011-11-01

    Density (ρ), viscosity (η) and ultrasonic velocity (u) of binary mixtures of methyl orange and water were measured at different concentrations and at different temperatures; several useful parameters such as excess volume, excess velocity, and excess adiabatic compressibility have been calculated. These parameters are used to explain the nature of intermolecular interactions taking place in the binary mixture. The above study is helpful in understanding the dye/solvent interaction at different concentration and temperatures.

  6. Molecular dynamics simulation of the structure and dynamics of water-1-alkyl-3-methylimidazolium ionic liquid mixtures.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M

    2011-06-02

    We have performed extensive molecular dynamic simulations to analyze the influence of cation and anion natures, and of water concentration, on the structure and dynamics of water-1-alkyl-3-methylimidazolium ionic liquid mixtures. The dependence on water concentration of the radial distribution functions, coordination numbers, and hydrogen bonding degree between the different species has been systematically analyzed for different lengths of the cation alkyl chain (alkyl = ethyl, butyl, hexyl, and octyl) and several counterions. These include two halogens of different sizes and positions in Hoffmeister series, Cl(-) and Br(-), and the highly hydrophobic inorganic anion PF(6)(-) throughout its whole solubility regime. The formation of water clusters in the mixture has been verified, and the influences of both anion hydrophobicity and cation chain length on the structure and size of these clusters have been analyzed. The water cluster size is shown to be relatively independent of the cation chain length, but strongly dependent on the hydrophobicity of the anion, which also determines critically the network formation of water and therefore the miscibility of the ionic liquid. The greater influence of the anion relative to the cation one is seen to be reflected in all the analyzed physical properties. Finally, single-particle dynamics in IL-water mixtures is considered, obtaining the self-diffusion coefficients and the velocity autocorrelation functions of water molecules in the mixture, and analyzing the effect of cation, anion, and water concentration on the duration of the ballistic regime and on the time of transition to the diffusive regime. Complex non-Markovian behavior was detected at intermediate times within an interval progressively shorter as water concentration increases.

  7. Excess molar volumes and viscosities of binary mixtures of 1,2-diethoxyethane with chloroalkanes at 298 15 K

    Indian Academy of Sciences (India)

    Amalendu Pal; Rakesh Kumar Bhardwaj

    2001-06-01

    Excess molar volumes ($V^{E}_{m}$) and viscosities () of the binary mixtures of 1,2-diethoxyethane with di-, tri- and tetrachloromethane have been measured at 298.15 K and atmospheric pressure over the entire mole fraction range. The deviations in viscosities (ln) and excess energies of activation ( *) for viscous flow have been calculated from the experimental data. The Prigogine-Flory-Patterson (PFP) model has been used to calculate $V^{E}_{m}$, and the results have been compared with experimental data. The Bloomfield and Dewan model has been used to calculate viscosity coefficients and these have also been compared with experimental data for the three mixtures. The results have been discussed in terms of dipole-dipole interactions between 1,2-diethoxyethane and chloroalkanes and their magnitudes decreasing with the dipole character of the molecules. A short comparative study with results for mixtures with polyethers and chloroalkanes is also described.

  8. Differentiation of Chemical Components in a Binary Solvent Vapor Mixture Using Carbon/Polymer Composite-Based Chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sanjay V.; Jenkins, Mark W.; Hughes, Robert C.; Yelton, W. Graham; Ricco, Antonio J.

    1999-07-19

    We demonstrate a ''universal solvent sensor'' constructed from a small array of carbon/polymer composite chemiresistors that respond to solvents spanning a wide range of Hildebrand volubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs solvent vapors, the composite film swells, the average separation between carbon particles increases, and an increase in film resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, dlisopropyhnethylphosphonate (DIMP), and water are correctly identified (''classified'') using three chemiresistors, their composite coatings chosen to span the full range of volubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified, following classification, two sensors suffice to determine the concentrations of both vapor components. Polyethylene vinylacetate and polyvinyl alcohol (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon-particle-composite films are sensitive to less than 0.25{degree}A relative humidity. The Sandia-developed VERI (Visual-Empirical Region of Influence) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from water vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal components analysis, VERI handles both linear and nonlinear data with equal ease. In the present study the maximum speciation accuracy is achieved by an array

  9. The potential of incorporation of binary salts and ionic liquid in P(VP-co-VAc) gel polymer electrolyte in electrochemical and photovoltaic performances

    Science.gov (United States)

    Ming, Ng Hon; Ramesh, S.; Ramesh, K.

    2016-06-01

    In this study, dye-sensitized solar cells (DSSCs) has been assembled with poly(1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VAc)) gel polymer electrolytes (GPEs) which have been incorporated with binary salt and an ionic liquid. The potential of this combination was studied and reported. The binary salt system GPEs was having ionic conductivity and power conversion efficiency (PCE) that could reach up to 1.90 × 10‑3 S cm‑1 and 5.53%, respectively. Interestingly, upon the addition of the ionic liquid, MPII into the binary salt system the ionic conductivity and PCE had risen steadily up to 4.09 × 10‑3 S cm‑1 and 5.94%, respectively. In order to know more about this phenomenon, the electrochemical impedance studies (EIS) of the GPE samples have been done and reported. Fourier transform infrared studies (FTIR) and thermogravimetric analysis (TGA) have also been studied to understand more on the structural and thermal properties of the GPEs. The Nyquist plot and Bodes plot studies have been done in order to understand the electrochemical properties of the GPE based DSSCs and Tafel polarization studies were done to determine the electrocatalytic activity of the GPE samples.

  10. Binary mixtures of diclofenac with paracetamol, ibuprofen, naproxen, and acetylsalicylic acid and these pharmaceuticals in isolated form induce oxidative stress on Hyalella azteca.

    Science.gov (United States)

    Gómez-Oliván, Leobardo Manuel; Neri-Cruz, Nadia; Galar-Martínez, Marcela; Islas-Flores, Hariz; García-Medina, Sandra

    2014-11-01

    Toxicity in natural ecosystems is usually not due to exposure to a single substance, but is rather the result of exposure to mixtures of toxic substances. Knowing the effects of contaminants as a mixture compared to their effects in isolated form is therefore important. This study aimed to evaluate the oxidative stress induced by binary mixtures of diclofenac with paracetamol, ibuprofen, naproxen, and acetylsalicylic acid and by these nonsteroidal anti-inflammatory drugs (NSAIDs) in isolated form, using Hyalella azteca as a bioindicator. The median lethal concentration (LC50) and the lowest observed adverse effect level (LOAEL) of each NSAID were obtained. Amphipods were exposed for 72 h to the latter value in isolated form and as binary mixtures. The following biomarkers were evaluated: lipid peroxidation (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Significant increases in LPX and PCC with respect to the control group (p ≤ 0.05) were induced by NSAIDs both in isolated form and as binary mixtures. Changes in SOD, CAT, and GPx activity likewise occurred with NSAIDs in isolated form and as binary mixtures. In conclusion, NSAIDs used in this study induce oxidative stress on H. azteca both in isolated form and as binary mixtures, and the interactions occurring between these pharmaceuticals are probably antagonistic in type.

  11. Determination and modelling of osmotic coefficients and vapour pressures of binary systems 1- and 2-propanol with C{sub n}MimNTf{sub 2} ionic liquids (n = 2, 3, and 4) at T = 323.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Calvar, Noelia [LSRE - Laboratory of Separation and Reaction Engineering, Associate Laboratory, LSRE/LCM, Department of Chemical Engineering, Faculty of Engineering, Rua Dr. Roberto Frias s/n, Porto 4200-465 (Portugal); Gomez, Elena; Dominguez, Angeles [Advanced Separation Processes Group, Department of Chemical Engineering, University of Vigo, 36310 Vigo (Spain); Macedo, Eugenia A., E-mail: eamacedo@fe.up.pt [LSRE - Laboratory of Separation and Reaction Engineering, Associate Laboratory, LSRE/LCM, Department of Chemical Engineering, Faculty of Engineering, Rua Dr. Roberto Frias s/n, Porto 4200-465 (Portugal)

    2011-08-15

    Highlights: > Osmotic coefficients of 1- and 2-propanol with C{sub n}MimNTf{sub 2} (n = 2, 3, and 4) are determined. > Experimental data were correlated with extended Pitzer model of Archer and MNRTL. > Mean molal activity coefficients and excess Gibbs free energies were calculated. > Effect of the anion is studied comparing these results with literature. - Abstract: The osmotic and activity coefficients and vapour pressures of binary mixtures containing 1-propanol, or 2-propanol and imidazolium-based ionic liquids with bis(trifluoromethylsulfonyl)imide as anion (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, C{sub 2}MimNTf{sub 2}, 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, C{sub 3}MimNTf{sub 2}, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, C{sub 4}MimNTf{sub 2}) were determined at T = 323.15 K using the vapour pressure osmometry technique. The experimental osmotic coefficients were correlated using the extended Pitzer model modified by Archer and the MNRTL model, obtaining standard deviations lower than 0.033 and 0.064, respectively. The mean molal activity coefficients and the excess Gibbs free energy for the mixtures studied were calculated from the parameters of the extended Pitzer model modified by Archer. Besides the effect of the alkyl-chain of the cation, the effect of the anion can be assessed comparing the experimental results with those previously obtained for imidazolium ionic liquids with sulphate anions.

  12. Order Parameter Profile in AN Adsorbed Binary Liquid Mixture Near Criticality.

    Science.gov (United States)

    Schlossman, Mark Loren

    Adsorption of a binary liquid mixture near criticality onto a solid glass substrate can be studied using light reflected off the glass/liquid boundary. In Part 1, reflectivity data analyzed with a modified Landau-Ginzburg theory using a contact wall interaction are shown to be consistent with an exponential decay of the order parameter into the bulk. This analysis provides a measure of h_{1 }, the effective glass/liquid interaction strength. The reflectivity can also be expressed as an expansion in the moments of the order parameter profile. For the data presented and an exponential profile the expansion can be truncated at the first order moment, M_{1} . We assume an exponential form of the profile to express the zeroth moment as a function of M _{1}. The first moment is fitted as a power law in t, the reduced temperature. Analysis of these data yields an exponent p = 0.88 +/- 0.10 that is consistent with the prediction p = 2nu - beta from the scaling law of Fisher and de Gennes. To further explore the profile an AC ellipsometer which used a photoelastic modulator was constructed. An unusual thermostat without traditional windows allowed the angle of incidence at the glass/liquid boundary to be varied over a large range. This allowed a large region in k -space to be explored, where k is twice the transmitted momentum wave vector perpendicular to the glass/liquid boundary. Excellent temperature control (0.1 mK/several hours) allowed the quantity kxi to be as large as kxi cong 15, where xi is the bulk correlation length. This should have allowed us to explore the power law region of the profile. During the investigation of the adsorption, certain anomalous data far above T _{c} (the critical temperature) were discovered. Temperature dependent hysteresis and very long equilibration times characterize the data. Until resolved, these features restrict progress in understanding the data closer to T_{c}. The data remain unexplained and are discussed, along with the

  13. Self-assembly in dilute mixtures of non-ionic and anionic surfactants and rhamnolipd biosurfactants.

    Science.gov (United States)

    Liley, J R; Penfold, J; Thomas, R K; Tucker, I M; Petkov, J T; Stevenson, P S; Banat, I M; Marchant, R; Rudden, M; Terry, A; Grillo, I

    2017-02-01

    The self-assembly of dilute aqueous solutions of a ternary surfactant mixture and rhamnolipid biosurfactant/surfactant mixtures has been studied by small angle neutron scattering. In the ternary surfactant mixture of octaethylene glycol monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene monododecyl sulfate, SLES, small globular interacting micelles are observed over the entire composition and concentration range studied. The modelling of the scattering data strongly supports the assumption that the micelle compositions are close to the solution compositions. In the 5-component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, di-rhamnose, R2, rhamnolipids with C12E8/LAS/SLES, globular micelles are observed over much of the concentration and composition range studied. However, for solutions relatively rich in rhamnolipid and LAS, lamellar/micellar coexistence is observed. The transition from globular to more planar structures arises from a synergistic packing in the 5 component mixture. It is not observed in the individual components nor in the ternary C12E8/LAS/SLES mixture at these relatively low concentrations. The results provide an insight into how synergistic packing effects can occur in the solution self-assembly of complex multi-component surfactant mixtures, and give rise to an unexpected evolution in the phase behaviour.

  14. Investigating the Effect of the Binary Mixtures Composition of Noble Gases on Their Thermodynamic and Transport Properties

    Directory of Open Access Journals (Sweden)

    S. A. Burtsev

    2015-01-01

    Full Text Available The paper presents possible application fields of the binary noble gas mixtures with low Prandtl numbers. It shows that it is expedient to select these mixtures as the working fluids for closed Brayton cycle gas-turbine installations, thermo-acoustic engines and for the gas dynamic energy separation device (Leontiev tube. As follows from the analysis, He-Ar, He-Kr, and HeXe mixtures have proven to be the most attractive choice. The paper has analyzed the calculation results for coefficient of dynamic viscosity, coefficient of thermal conductivity, and for heat capacity at constant pressure for the given mixtures in terms of mixture molecular weights at pressures of 2MPa and 7MPa and temperatures of 400 and 1200°K. According to data of experiments and calculations available in public sources published by another authors, the results are verified. It was found that at constant pressure within the examined range of parameters (i.e. pressure, temperature, mixture molecular weight the obtained heat capacity values are in good agreement with the values of the verification data. In calculating dynamic viscosity coefficient for any pressure and temperature the utilized technique provides results for He-Ar and He-Kr mixtures within the entire range of the molecular weights, which are, essentially, as good as shown by international verification techniques. However, at high pressures and low temperatures for He-Xe mixture with molecular weights close to the pure Xe the divergence was found to be as high as 25 % while for other parameter intervals under consideration and with the same mixture the difference does not exceed 10 %. A good agreement with the verification data is observed for the values of a thermal conductivity coefficient of He-Ar and He-Kr mixtures for any value of parameters, while for He-Xe mixture with molecular weights close to 60 g/mole independently of pressure the divergence can reach 30 % for 1200°K and 20 % for 400°K. It is shown

  15. INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE

    Directory of Open Access Journals (Sweden)

    C. C. Lobo

    Full Text Available Abstract In this work the aerobic degradation of phenol (PH, catechol (CA, resorcinol (RE, hydroquinone (HY and of the binary mixtures PH+CA, PH+RE, PH+HY by phenol-acclimated activated sludge was studied. Single substrate experiments show a Haldane-type dependence of the respiration rate on PH, RE and HY, while CA corresponded to the Monod model. Binary substrate experiments demonstrated that the presence of a second substrate only affected the kinetics, but not the stoichiometry of the oxidation of the compounds tested. While CA inhibited the oxidation of PH, PH inhibited the oxidation of RE and HY. A mathematical model was developed to represent the aerobic biodegradation of the phenolic compounds tested. The agreement between the proposed model and the experimental data indicates that the proposed model can be useful for predicting substrate and dissolved oxygen concentrations in bioreactors treating phenolic wastewaters.

  16. Binary and ternary ionic compounds in the outer crust of a cold nonaccreting neutron star

    Science.gov (United States)

    Chamel, N.; Fantina, A. F.

    2016-12-01

    The outer crust of a cold nonaccreting neutron star has been generally assumed to be stratified into different layers, each of which consists of a pure body-centered cubic ionic crystal in a charge compensating background of highly degenerate electrons. The validity of this assumption is examined by analyzing the stability of multinary ionic compounds in dense stellar matter. It is thus shown that their stability against phase separation is uniquely determined by their structure and their composition irrespective of the stellar conditions. However, equilibrium with respect to weak and strong nuclear processes imposes very stringent constraints on the composition of multinary compounds, and thereby on their formation. By examining different cubic and noncubic lattices, it is found that substitutional compounds having the same structure as cesium chloride are the most likely to exist in the outer crust of a nonaccreting neutron star. The presence of ternary compounds is also investigated. Very accurate analytical expressions are obtained for the threshold pressure, as well as for the densities of the different phases irrespective of the degree of relativity of the electron gas. Finally, numerical calculations of the ground-state structure and of the equation of state of the outer crust of a cold nonaccreting neutron star are carried out using recent experimental and microscopic nuclear mass tables.

  17. CFD modelling of most probable bubble nucleation rate from binary mixture with estimation of components' mole fraction in critical cluster

    Science.gov (United States)

    Hong, Ban Zhen; Keong, Lau Kok; Shariff, Azmi Mohd

    2016-05-01

    The employment of different mathematical models to address specifically for the bubble nucleation rates of water vapour and dissolved air molecules is essential as the physics for them to form bubble nuclei is different. The available methods to calculate bubble nucleation rate in binary mixture such as density functional theory are complicated to be coupled along with computational fluid dynamics (CFD) approach. In addition, effect of dissolved gas concentration was neglected in most study for the prediction of bubble nucleation rates. The most probable bubble nucleation rate for the water vapour and dissolved air mixture in a 2D quasi-stable flow across a cavitating nozzle in current work was estimated via the statistical mean of all possible bubble nucleation rates of the mixture (different mole fractions of water vapour and dissolved air) and the corresponding number of molecules in critical cluster. Theoretically, the bubble nucleation rate is greatly dependent on components' mole fraction in a critical cluster. Hence, the dissolved gas concentration effect was included in current work. Besides, the possible bubble nucleation rates were predicted based on the calculated number of molecules required to form a critical cluster. The estimation of components' mole fraction in critical cluster for water vapour and dissolved air mixture was obtained by coupling the enhanced classical nucleation theory and CFD approach. In addition, the distribution of bubble nuclei of water vapour and dissolved air mixture could be predicted via the utilisation of population balance model.

  18. Photoinduced toxicity single and binary mixtures of four polycyclic aromatic hydrocarbons to the marine diatom Skeletonema costatum

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Diatom Skeletonema costatum Cleve is one of the main predominant phytoplankton species in the Changjiang Estuary in China. In order to provide some basic information for future assessment of the potential risk on phytoplankton communities in this estuary caused by polycyclic aromatic hydrocarbons(PAHs), this alga was selected as a representative to investigate the photoinduced toxicity of PAHs, in single and mixture. Four PAHs including three-ring phenanthrene and anthracene, four-ring fluoranthene and pyrene were tested in the laboratory. The single toxicity of each PAH on this microalga was compared with and without the simulated solar UV radiation. The results showed that this microalga was sensitive to PAH's photoinduced toxicity. Ratios of the 72 h median effect concentration obtained for fluorescent and UV light tests were about 8.4 for phenanthrene, 13.0 for anthracene, 6.5 for fluoranthene, and 5.7 for pyrene, indicating that UV light enhanced the PAH toxicity to this alga significantly. Under the fluorescent radiation (lacking UV), the dose-response curves based on chemical concentrations revealed that the order of toxic strength was fluoranthene greater than pyrene greater than anthracene greater than phenanthrene; while under the UV radiation (476 μW/cm2 for UVA, 6.5 μW/cm2 for UVB) it became fluoranthene approximately equaling anthracene greater than pyrene greater than phenanthrene, indicating that the UV light also changed its relative toxicity to this alga. The photoinduced toxicity of PAHs to the marine diatom S. costatum might be a synergistic effect of photosensitization reactions (e.g., generation of single-state oxygen) and photomodification (photooxidation and/or photolysis).The combined effects of six binary mixtures on the marine diatom S. costatum were investigated using the additive-index method. Four binary-mixtures (phenanthrene plus anthracene; phenanthrene plus pyrene; anthracene plus fluoranthene; anthracene plus pyrene) were found

  19. Excess volumes and excess viscosities of binary mixtures of some cyclic ethers + bromocyclohexane at 298.15 and 313.15 K

    Science.gov (United States)

    Rodríguez, S.; Lafuente, C.; Carrión, J. A.; Royo, F. M.; Urieta, J. S.

    1996-11-01

    Excess Volumes, V E, and excess viscosities, η E, at 293.15 and 313.15 K are reported for binary mixtures of some cyclic ethers (tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran and 2,5-dimethyltetrahydrofuran) + bromocyclohexane. These properties were obtained from density and viscosity measurements. γ E and η E show negatives values for all the mixtures.

  20. Systematic screening methodology and energy efficient design of ionic liquid-based separation processes

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2016-01-01

    A systematic methodology for the screening of ionic liquids (ILs) as entrainers and for the design of ILs-based separation processes in various homogeneous binary azeotropic mixtures has been developed. The methodology focuses on the homogeneous binary aqueous azeotropic systems (for example, wat...

  1. Influence of porewater velocity and ionic strength on DOC concentrations in and losses from peat-sand mixtures

    Science.gov (United States)

    Pfaffner, Nora; Tiemeyer, Bärbel; Fiedler, Sabine

    2015-04-01

    Organic soils play an important role in the global carbon cycle as they can act as a source or a sink for greenhouse gas emissions. The new IPCC Wetlands Supplement accounts for the first time for CO2 emissions from the decomposition of dissolved organic carbon (DOC). While there is a wealth of studies on "true" peat soils, knowledge on DOC losses from organic soils heavily disturbed by e.g. mixing with sand is fragmentary. Moreover, there are only a few studies on the influence of soil hydrological properties on DOC transport. This study investigates physico-chemical controls on the concentration and losses of DOC from a peat-sand mixture in a saturated column experiment with undisturbed columns. The soil originates from the study site "Grosses Moor" (Northern Germany) which is a former bog where peat layers remaining after peat mining were mixed with the underlying mineral soil. We studied the influence of the flow regime and the ionic strength of the irrigation solution on DOC concentrations and losses. Three different pumping rates and two different ionic strengths determined by different concentrations of a sodium chloride-calcium chloride mixture in the irrigation solution were applied. Transport properties of the soil were obtained by analyzing breakthrough curves (BTCs) of a conservative tracer (potassium bromide). For interpretation of the BTCs, the transport model STANMOD which is based on the two-region (mobile/immobile) non-equilibrium concept was fitted to the data. The shape of the BTCs and the STANMOD results showed that three of the four columns had a dual porosity structure, which affects the porewater velocity and the contact area. After a large initial peak, DOC concentrations equilibrated to nearly constant values. Increased porewater velocities decreased the concentration of DOC, but increased the losses. A new equilibrium concentration was reached after nearly all changes of the porewater velocity. At maximum pumping rates as determined from

  2. Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Guerfi, A.; Dontigny, M.; Charest, P.; Petitclerc, M.; Lagace, M.; Vijh, A.; Zaghib, K. [Institut de Recherche d' Hydro-Quebec, 1800 Lionel Boulet, Varennes, QC J3X 1S1 (Canada)

    2010-02-01

    Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO{sub 4} cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is {>=}40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO{sub 4} is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO{sub 4} cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155 mAh g{sup -1} at C/12 is obtained with cells having at least some organic electrolyte compared to only 124 mAh g{sup -1} with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2 C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO{sub 4}//Li{sub 4}Ti{sub 5}O{sub 12} with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2 C rate

  3. Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance

    Science.gov (United States)

    Guerfi, A.; Dontigny, M.; Charest, P.; Petitclerc, M.; Lagacé, M.; Vijh, A.; Zaghib, K.

    Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO 4 cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is ≥40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO 4 is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO 4 cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155 mAh g -1 at C/12 is obtained with cells having at least some organic electrolyte compared to only 124 mAh g -1 with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2 C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO 4//Li 4Ti 5O 12 with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2 C rate. This study indicates that safety and

  4. Experimental determination and prediction of (solid+liquid) phase equilibria for binary mixtures of heavy alkanes and fatty acids

    Science.gov (United States)

    Benziane, Mokhtar; Khimeche, Kamel; Dahmani, Abdellah; Nezar, Sawsen; Trache, Djalal

    2012-06-01

    Solid-liquid equilibria for three binary mixtures, n-Eicosane (1) + Lauric acid (2), n-Tetracosane (1) + Stearic acid (2), and n-Octacosane (1) + Palmitic acid (2), were measured using a differential scanning calorimeter. Simple eutectic behaviour was observed for these systems. The experimental results were correlated by means of the modified UNIFAC (Larsen and Gmehling versions), UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.26 to 3.15 K and depend on the particular model used. The best solubility correlation was obtained with the UNIQUAC model.

  5. Structure formation in binary mixtures of surfactants: vesicle opening-up to bicelles and octopus-like micelles

    Science.gov (United States)

    Noguchi, Hiroshi

    Micelle formation in binary mixtures of surfactants is studied using a coarse-grained molecular simulation. When a vesicle composed of lipid and detergent types of molecules is ruptured, a disk-shaped micelle, the bicelle, is typically formed. It is found that cup-shaped vesicles and bicelles connected with worm-like micelles are also formed depending on the surfactant ratio and critical micelle concentration. The obtained octopus shape of micelles agree with those observed in the cryo-TEM images reported in [S. Jain and F. S. Bates, Macromol. 37, 1511 (2004).]. Two types of connection structures between the worm-like micelles and the bicelles are revealed.

  6. Densities, Ultrasonic Speeds, Viscosities and Refractive Indices of Binary Mixtures of Benzene with Benzyl Alcohol,Benzonitrile, Benzoyl Chloride and Chlorobenzene at 303.15 K

    Institute of Scientific and Technical Information of China (English)

    ALI,A.; PANDEY,J.D.; SONI,N.K.; NAIN,A.K.; LAL,B.; CHAND,D.

    2005-01-01

    Densities, p, ultrasonic speeds, u, viscosities, η, and refractive indices, n, of pure benzene, benzyl alcohol (BA),benzonitrile (BN), benzoyl chloride (BC), chlorobenzene (CB) and their thirty six binary mixtures, with benzene as common component, were measured at 303.15 K over the entire mole fraction range. From these experimental data the values of deviations in ultrasonic speed, Au, isentropic compressibility, Δks, excess acoustic impedance, ZE, deviation in viscosity, Δη, and excess Gibbs free energy of activation of viscous flow, G*E, and partial molar isentropic compressibility, Kφ,2 of BA, BN, BC and CB in benzene were computed. The variation of these derived functions with composition of the mixtures suggested the increased cohesion (molecular order) in the solution and that interaction (A-B)>(A-A) or (B-B). Moreover, theoretical prediction of ultrasonic speed, viscosity and refractive index of all the four binary mixtures was made on the basis of empirical and semi-empirical relations by using the experimental values of the pure components. Comparison of theoretical results with the experimental values was made in order to assess the suitability of these relations in reproducing the experimental values of u, η and n. Also, molecular radii of pure liquids and the average molecular radii of binary mixtures were evaluated using the corresponding refractive indices of pure liquids and binary mixtures. The average molecular radii of binary mixtures were found to be additive with respect to mole fraction of the pure component.

  7. Multiphase Binary Mixture Flows in Porous Media in a Wide Pressure and Temperature Range Including Critical Conditions

    Science.gov (United States)

    Afanasyev, A.

    2011-12-01

    Multiphase flows in porous media with a transition between sub- and supercritical thermodynamic conditions occur in many natural and technological processes (e.g. in deep regions of geothermal reservoirs where temperature reaches critical point of water or in gas-condensate fields where subject to critical conditions retrograde condensation occurs and even in underground carbon dioxide sequestration processes at high formation pressure). Simulation of these processes is complicated due to degeneration of conservation laws under critical conditions and requires non-classical mathematical models and methods. A new mathematical model is proposed for efficient simulation of binary mixture flows in a wide range of pressures and temperatures that includes critical conditions. The distinctive feature of the model lies in the methodology for mixture properties determination. Transport equations and Darcy law are solved together with calculation of the entropy maximum that is reached in thermodynamic equilibrium and determines mixture composition. To define and solve the problem only one function - mixture thermodynamic potential - is required. Such approach allows determination not only single-phase states and two-phase states of liquid-gas type as in classical models but also two-phase states of liquid-liquid type and three-phase states. The proposed mixture model was implemented in MUFITS (Multiphase Filtration Transport Simulator) code for hydrodynamic simulations. As opposed to classical approaches pressure, enthalpy and composition variables together with fully implicit method and cascade procedure are used. The code is capable of unstructured grids, heterogeneous porous media, relative permeability and capillary pressure dependence on temperature and pressure, multiphase diffusion, optional number of sink and sources, etc. There is an additional module for mixture properties specification. The starting point for the simulation is a cubic equation of state that is

  8. An Analytic Equation of State Based on SAFT-CP for Binary Non-Polar Alkane Mixtures Across the Critical Point

    Institute of Scientific and Technical Information of China (English)

    周文来; 密建国; 贺刚; 于燕梅; 陈健

    2003-01-01

    The description using an analytic equation of state of thermodynamic properties near the critical points of fluids and their mixtures remains a challenging problem in the area of chemical engineering. Based on the statistical associating fluid theory across the critical point (SAFT-CP), an analytic equation of state is established in this work for non-polar mixtures. With two binary parameters, this equation of state can be used to calculate not only vapor-liquid equilibria but also critical properties of binary non-polar alkane mixtures with acceptable deviations.

  9. Utilization of an Ionic Liquid/Urea Mixture as a Physical Coupling Agent for Agarose/Talc Composite Films

    Directory of Open Access Journals (Sweden)

    Rusli Daik

    2013-02-01

    Full Text Available An ionic liquid, 1-n-butyl-3-methylimidazolium chloride (BmimCl was blended with urea at 1:1 mole ratio to create a BmimCl/Urea mixture. The agarose/talc composite films containing the BmimCl/Urea mixture were then acquired through a gelation method. The weight ratio of agarose and talc was fixed at 4:1, while the content of BmimCl/Urea was varied from 0 to 10 wt % relative to the overall weight of the composite films. The tensile stress and modulus results showed the optimum BmimCl/Urea content in the composite film lies at 8 wt %. The talc particles are embedded in the agarose matrix and there are no pullouts for the composite films containing BmimCl/Urea as demonstrated by SEM micrographs. The addition of BmimCl/Urea increased the glass transition temperature of the composite films, however, the thermal decomposition temperature decreased drastically. FTIR and FT-Raman spectra indicated the existence of interaction between agarose and talc, which improves their interfacial adhesion. As a conclusion, a BmimCl/Urea mixture can be utilized as a coupling agent for agarose/talc composite films.

  10. Volumetric, viscometric and optical study of molecular interactions in binary mixtures of diethyl malonate with ketones at 303.15, 308.15 and 313.15K

    Directory of Open Access Journals (Sweden)

    Rathnam Manapragada V.

    2012-01-01

    Full Text Available Density ρ, viscosity η, and refractive index nD were measured for the binary mixtures of diethyl malonate with ketones (acetophenone, cyclopentanone, cyclohexanone and 3-pentanone at temperatures (303.15, 308.15 and 313.15 K over the entire composition range. Excess volume VE, deviation in viscosity Δη, excess Gibb’s free energy of activation for viscous flow ΔGE and deviation in molar refraction ÄR were determined from the experimental data and computed results were fitted to the Redlich-Kister polynomial equation. The values of VE, Δη, ΔGE, and ΔR were plotted against the mole fraction of diethyl malonate. The observed positive and negative values of excess parameters for all the studied binary mixtures were explained on the basis of intermolecular interactions present in these mixtures. Further different empirical relations were used to correlate the binary mixture viscosities and refractive indices.

  11. Thermoacoustical and Excess Properties of Binary Mixtures of Ethyl Butyrate with Methanol and Vinyl Acetate

    Directory of Open Access Journals (Sweden)

    Jagdish Prasad Shukla

    2010-06-01

    Full Text Available This paper aims to portray the nature of interaction present in the mixture of ethyl butyrate with methanol and vinyl acetate by computing various thermodynamic parameters at 298.15 K. Excess thermodynamic properties correlated with Redlich–Kister polynomial equation reveals the extent of interaction present in the mixture. Acoustical relations giving the molecular radii of liquid mixtures suggest the change in structure with composition quite well. A comparative study of various empirical and semi-empirical relations such as Flory’s Statistical Theory, Goldsack and Sarvas, Sanchez theory etc. for predicting ultrasonic velocity of the mixtures with the experimental values have been done.

  12. Theory and simulations for hard-disk models of binary mixtures of molecules with internal degrees of freedom

    DEFF Research Database (Denmark)

    Fraser, Diane P.; Zuckermann, Martin J.; Mouritsen, Ole G.

    1991-01-01

    by the method in the case of a binary mixture, and results are presented for varying disk-size ratios and degeneracies. The results are also compared with the predictions of the extended scaled-particle theory. Applications of the model are discussed in relation to lipid monolayers spread on air......A two-dimensional Monte Carlo simulation method based on the NpT ensemble and the Voronoi tesselation, which was previously developed for single-species hard-disk systems, is extended, along with a version of scaled-particle theory, to many-component mixtures. These systems are unusual in the sense...... that their composition is not fixed, but rather determined by a set of internal degeneracies assigned to the differently sized hard disks, where the larger disks have the higher degeneracies. Such systems are models of monolayers of molecules with internal degrees of freedom. The combined set of translational...

  13. Different signal processing techniques of ratio spectra for spectrophotometric resolution of binary mixture of bisoprolol and hydrochlorothiazide; a comparative study.

    Science.gov (United States)

    Elzanfaly, Eman S; Hassan, Said A; Salem, Maissa Y; El-Zeany, Badr A

    2015-04-01

    Five signal processing techniques were applied to ratio spectra for quantitative determination of bisoprolol (BIS) and hydrochlorothiazide (HCT) in their binary mixture. The proposed techniques are Numerical Differentiation of Ratio Spectra (ND-RS), Savitsky-Golay of Ratio Spectra (SG-RS), Continuous Wavelet Transform of Ratio Spectra (CWT-RS), Mean Centering of Ratio Spectra (MC-RS) and Discrete Fourier Transform of Ratio Spectra (DFT-RS). The linearity of the proposed methods was investigated in the range of 2-40 and 1-22 μg/mL for BIS and HCT, respectively. The proposed methods were applied successfully for the determination of the drugs in laboratory prepared mixtures and in commercial pharmaceutical preparations and standard deviation was less than 1.5. The five signal processing techniques were compared to each other and validated according to the ICH guidelines and accuracy, precision, repeatability and robustness were found to be within the acceptable limit.

  14. Gibb's energy and intermolecular free length of 'Borassus Flabellifier' (BF) and Adansonia digitata (AnD) aqueous binary mixture

    Science.gov (United States)

    Phadke, Sushil; Darshan Shrivastava, Bhakt; Ujle, S. K.; Mishra, Ashutosh; Dagaonkar, N.

    2014-09-01

    One of the potential driving forces behind a chemical reaction is favourable a new quantity known as the Gibbs free energy (G) of the system, which reflects the balance between these forces. Ultrasonic velocity and absorption measurements in liquids and liquid mixtures find extensive application to study the nature of intermolecular forces. Ultrasonic velocity measurements have been successfully employed to detect weak and strong molecular interactions present in binary and ternary liquid mixtures. After measuring the density and ultrasonic velocity of aqueous solution of 'Borassus Flabellifier' BF and Adansonia digitata And, we calculated Gibb's energy and intermolecular free length. The velocity of ultrasonic waves was measured, using a multi-frequency ultrasonic interferometer with a high degree of accuracy operating Model M-84 by M/s Mittal Enterprises, New Delhi, at a fixed frequency of 2MHz. Natural sample 'Borassus Flabellifier' BF fruit pulp and Adansonia digitata AnD powder was collected from Dhar, District of MP, India for this study.

  15. Assessment of the micro-structure and depletion potentials in two-dimensional binary mixtures of additive hard-disks

    Science.gov (United States)

    Perera-Burgos, Jorge Adrián; Méndez-Alcaraz, José Miguel; Pérez-Ángel, Gabriel; Castañeda-Priego, Ramón

    2016-09-01

    Depletion forces are a particular class of effective interactions that have been mainly investigated in binary mixtures of hard-spheres in bulk. Although there are a few contributions that point toward the effects of confinement on the depletion potential, little is known about such entropic potentials in two-dimensional colloidal systems. From theoretical point of view, the problem resides in the fact that there is no general formulation of depletion forces in arbitrary dimensions and, typically, any approach that works well in three dimensions has to be reformulated for lower dimensionality. However, we have proposed a theoretical framework, based on the formalism of contraction of the description within the integral equations theory of simple liquids, to account for effective interactions in colloidal liquids, whose main feature is that it does not need to be readapted to the problem under consideration. We have also shown that such an approach allows one to determine the depletion pair potential in three-dimensional colloidal mixtures even near to the demixing transition, provided the bridge functions are sufficiently accurate to correctly describe the spatial correlation between colloids [E. López-Sánchez et al., J. Chem. Phys. 139, 104908 (2013)]. We here report an extensive analysis of the structure and the entropic potentials in binary mixtures of additive hard-disks. In particular, we show that the same functional form of the modified-Verlet closure relation used in three dimensions can be straightforwardly employed to obtain an accurate solution for two-dimensional colloidal mixtures in a wide range of packing fractions, molar fractions, and size asymmetries. Our theoretical results are explicitly compared with the ones obtained by means of event-driven molecular dynamics simulations and recent experimental results. Furthermore, to assess the accuracy of our predictions, the depletion potentials are used in an effective one-component model to reproduce

  16. Laser photolysis study of anthraquinone in binary mixtures ofionic liquid [bmim][PF6] and organic solvent

    Directory of Open Access Journals (Sweden)

    Side Yao

    2006-12-01

    Full Text Available Photochemical properties of the ionic liquid (RTIL 1-butyl-3-methylimidazoliumhexafluorophosphate [bmim][PF6] and its binary mixed solutions with organic solvent(DMF and MeCN were investigated by laser photolysis at an excitation wavelength of 355nm, using anthraquinone (AQ as a probe molecule. It was indicated that the triplet excitedstate of AQ (3AQ* can abstract hydrogen from [bmim][PF6]. Moreover, along with thechange of the ratio of RTIL and organic solvent, the reaction rate constant changes regularly.Critical points were observed at volume fraction VRTIL = 0.2 for RTIL/MeCN and VRTIL =0.05 for RTIL/DMF. For both systems, before the critical point, the rate constant increasesrapidly with increasing VRTIL; however, it decreases obviously with VRTIL after the criticalpoint. We conclude that the concentration dependence is dominant at lower VRTIL, while theviscosity and phase transformation are dominant at higher VRTIL for the effect of ionic liquidon the decay of rate constant.

  17. Phase equilibria study of the binary systems (1-butyl-3-methylimidazolium thiocyanate ionic liquid + organic solvent or water).

    Science.gov (United States)

    Domańska, Urszula; Laskowska, M; Pobudkowska, Aneta

    2009-05-07

    (Solid + liquid) phase equilibria (SLE) for the binary systems, ionic liquid (IL) 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] with an alcohol (1-octanol, 1-nonanol, 1-decanol, 1-undecanol, or 1-dodecanol) or water, and (liquid + liquid) phase equilibria (LLE) for the binary systems of [BMIM][SCN] with an alkane (n-hexane, n-heptane, n-octane, n-nonane, or n-decane), benzene, an alkylbenzenes (toluene or ethylbenzene), tetrahydrofuran (THF), cycloalkanes (cyclohexane or cycloheptane), or ethers (di-n-propyl ether, di-n-butyl ether, di-n-pentyl ether, n-butylmethyl ether, tert-butylmethyl ether (MTBE), or tert-butylethyl ether (ETBE)) have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from 250 to 430 K. In the case of systems IL + alkane, cycloalkane, or ether, the mutual immiscibility with an upper critical solution temperature (UCST) was detected, and in the systems of IL + benzene, alkylbenzene, or THF, the mutual immiscibility with a lower critical solution temperature (LCST) was observed. UV-vis spectroscopy was used to determine the very small compositions of the IL in the n-hexane (about 2 x 10(-5) IL mole fraction), benzene (about 2 x 10(-3) IL mole fraction), cyclohexane (about 2 x 10(-5) IL mole fraction), and THF (about 1.2 x 10(-2) IL mole fraction). For the binary systems containing alcohol, it was noticed that with increasing chain length of an alcohol, the solubility decreases. The basic thermal properties of the pure IL, that is, the glass-transition temperature as well as the heat capacity at the glass-transition temperature, have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the IL was detected by the simultaneous TG/DTA experiments. Well-known UNIQUAC, Wilson, and NRTL equations have been used to correlate the experimental SLE data sets for alcohols and water. For the systems containing immiscibility gaps {IL + alkane

  18. Formation of H2-He Substellar Bodies in Cold Conditions: Gravitational Stability of Binary Mixtures in a Phase Transition

    CERN Document Server

    Füglistaler, Andreas

    2015-01-01

    Molecular clouds consist typically of 3/4 H2, 1/4 He and traces of heavier elements. In an earlier work we showed that at very low temperatures and high densities, H2 can be in a phase transition leading to the formation of ice clumps as large as comets, or even planets. However, He has very different chemical properties and no phase transition is expected before H2 in dense ISM conditions. The gravitational stability of fluid mixtures has been studied before, but not including a phase transition. We study the gravitational stability of binary fluid mixtures with special emphasis if one component is in a phase transition. The results are aimed at applications in molecular cloud conditions. We study the gravitational stability of van der Waals fluid mixtures using linearised analysis and examine virial equilibrium conditions using the Lennard-Jones inter-molecular potential. Then, combining the Lennard-Jones and gravitational potentials, the non-linear dynamics of fluid mixtures are studied using the molecular...

  19. Studies on the atomic capture of stopped negative pions in binary mixtures of /sup 3/He with other gases

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, A.V.; Levay, B.; Petrukhin, V.I.; Vasilyev, V.A. (Joint Inst. for Nuclear Research, Dubna (USSR)); Kochenda, L.M.; Markov, A.A.; Medvedev, V.I.; Sokolov, G.L.; Strakovsky, I.I. (Leningrad Nuclear Physics Inst., Gatchina (USSR)); Horvath, D. (Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1983-07-25

    Systematic experimental study has been carried out on the atomic capture of negative pions by /sup 3/He in binary gas mixtures of /sup 3/He + Z, where Z is Ne, Ar, Kr, Xe, N/sub 2/, O/sub 2/, CO/sub 2/ and SF/sub 6/. The results are analysed in the framework of a phenomenological model. It is shown that there is no pion transfer from the /sup 3/He..pi../sup -/ mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentraions, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A(Z//sup 3/He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a /sup 3/He + /sup 4/He mixture is A(/sup 4/He//sup 3/He) = 0.75 +- 0.13, which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest ..pi../sup -/ + /sup 3/He -> ..pi../sup 0/ + /sup 3/H) is found to be 0.128 +- 0.012.

  20. Studies on the atomic capture of stopped negative pions in binary mixtures of 3He with other gases

    Science.gov (United States)

    Bannikov, A. V.; Lévay, B.; Petrukhin, V. I.; Vasilyev, V. A.; Kochenda, L. M.; Markov, A. A.; Medvedev, V. I.; Sokolov, G. L.; Strakovsky, I. I.; Horváth, D.

    1983-07-01

    Systematic experimental study has been carried out on the atomic capture of negative pions by 3He in binary gas mixtures of 3He + Z, where Z is Ne, Ar, Kr, Xe, N 2, O 2, CO 2 and sf 6. The results are analysed in the framework of a phenomenological model. It is shown that there is no pion transfer from the 3Heπ - mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentrations, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A( Z/ 3He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a 3He + 4He mixture is A( 4He/ 3He) = 0.75 ± 0.13 , which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest (π - + 3He → π 0 + 3H) is found to be 0.128 ± 0.012.

  1. Studies on the atomic capture of stopped negative pions in binary mixtures of /sup 3/He with other gases

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, A.V.; Levay, B.; Petrukhin, V.I.; Vasilyev, V.A. (Joint Inst. for Nuclear Research, Dubna (USSR)); Kochenda, L.M.; Markov, A.A.; Medvedev, V.I.; Sokolov, G.L.; Strakovsky, I.I. (Leningrad Nuclear Physics Inst., Gatchina (USSR)); Horvath, D. (Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1983-07-25

    Systematic experimental study has been carried out on the atomic capture of negative pions by /sup 3/He in binary gas mixtures of /sup 3/He + Z, where Z is Ne, Ar, Kr, Xe, N/sub 2/, O/sub 2/, CO/sub 2/ and SF/sub 6/. The results are analyzed in the framework of a phenomenological model. It is shown that there is no pion transfer from the /sup 3/He..pi../sup -/ mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentraions, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A(Z//sup 3/He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a /sup 3/He + /sup 4/He mixture is A(/sup 4/He//sup 3/He) = 0.75 +- 0.13, which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest ..pi../sup -/ + /sup 3/He -> ..pi../sup 0/ + /sup 3/H is found to be 0.128 +- 0.012.

  2. On the solid–liquid phase diagrams of binary mixtures of even saturated fatty alcohols: Systems exhibiting peritectic reaction

    Energy Technology Data Exchange (ETDEWEB)

    Carareto, Natália D.D. [EXTRAE, Department of Food Engineering, Food Engineering Faculty, University of Campinas, UNICAMP, CEP 13083-862 Campinas, SP (Brazil); Santos, Adenílson O. dos [Social Sciences, Health and Technology Center, University of Maranhão, UFMA, CEP 65900-410 Imperatriz, MA (Brazil); Rolemberg, Marlus P. [Institute of Science and Technology, University of Alfenas, UNIFAL, Rodovia José AurélioVilela, CEP 37715400 Poços de Caldas, MG (Brazil); Cardoso, Lisandro P. [Institute of Physics GlebWataghin, University of Campinas, UNICAMP, C.P. 6165, CEP 13083-970 Campinas, SP (Brazil); Costa, Mariana C. [School of Applied Science, University of Campinas, UNICAMP, CEP 13484-350 Limeira, SP (Brazil); Meirelles, Antonio J.A., E-mail: tomze@fea.unicamp.br [EXTRAE, Department of Food Engineering, Food Engineering Faculty, University of Campinas, UNICAMP, CEP 13083-862 Campinas, SP (Brazil)

    2014-08-10

    Highlights: • SLE of binary mixtures of saturated fatty alcohols was studied. • Experimental data were obtained using DSC and stepscan DSC. • Microscopy and X-ray diffraction used as complementary techniques. • Systems presented eutectic, peritectic and metatectic points. - Abstract: The solid–liquid phase diagrams of the following binary mixtures of even saturated fatty alcohols are reported in the literature for the first time: 1-octanol (C8OH) + 1-decanol (C10OH), 1-decanol + 1-dodecanol (C12OH), 1-dodecanol + 1-hexadecanol (C16OH) and 1-tetradecanol (C14OH) + 1-octadecanol (C18OH). The phase diagrams were obtained by differential scanning calorimetry (DSC) using a linear heating rate of 1 K min{sup −1} and further investigated by using a stepscan DSC method. X-ray diffraction (XRD) and polarized light microscopy were also used to complement the characterization of the phase diagrams which have shown a complex global behavior, presenting not only peritectic and eutectic reactions, but also the metatectic reaction and partial immiscibility on solid state.

  3. The effect of individual phosphate emulsifying salts and their selected binary mixtures on hardness of processed cheese spreads

    Directory of Open Access Journals (Sweden)

    František Buňka

    2013-07-01

    Full Text Available Normal 0 false false false CS JA X-NONE The aim of this work was to observe the effects of emulsifying salts composed of trisodium citrate and sodium phosphates with different chain length (disodium phosphate (DSP, tetrasodium diphosphate (TSPP, pentasodium triphosphate (PSTP and sodium salts of polyphosphates with 5 different mean length (n ≈ 5, 9, 13, 20, 28 on hardness of processed cheese spreads. Hardness of processed cheese spreads with selected binary mixtures of the above mentioned salts were also studied. Measurements were performed after 2, 9 and 30 days of storage at 6 °C. Hardness of processed cheese increased with increase in chain length of individually used phosphates.  Majority of applied binary mixtures of emulsifying salts had not significant influence on hardness charges in processed cheese spreads. On the other hand, a combination of phosphates salts (DSP with TSPP was found, which had specific effect on hardness of processed cheese spreads. Textural properties of samples with trisodium citrate were similar compared to samples with DSP.

  4. Selection of ionic liquids for the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures

    NARCIS (Netherlands)

    Meindersma, G. Wytze; Podt, Anita (J.G.); Haan, de André B.

    2005-01-01

    The separation of aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) from C4 to C10 aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. In this work, we investigated the separation of t

  5. Thermodynamics of mixtures containing amines. IX. Application of the concentration-concentration structure factor to the study of binary mixtures containing pyridines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio, E-mail: jagl@termo.uva.es [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Cobos, Jose Carlos; Garcia de la Fuente, Isaias; Mozo, Ismael [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)

    2009-10-10

    Binary mixtures formed by a pyridine base and an alkane, or an aromatic hydrocarbon, or a 1-alkanol have been studied in the framework of the concentration-concentration structure factor, S{sub CC}(0), formalism. Deviations between experimental data and those provided by the DISQUAC model are discussed. Systems containing alkanes are characterized by homocoordination. In pyridine + alkane mixtures, S{sub CC}(0) decreases with the chain length of the longer alkanes, due to size effects. For a given alkane, S{sub CC}(0) also decreases with the number of CH{sub 3}- groups in the pyridine base. This has been interpreted assuming that the number of amine-amine interactions available to be broken upon mixing also decreases similarly, probably as steric hindrances exerted by the methyl groups of the aromatic amine increase with the number of these groups. Homocoordination is higher in mixtures with 3,5-dimethylpyridine than in those with 2,6-dimethylpyridine. That is, steric effects exerted by methyl groups in positions 3 and 5 are stronger than when they are in positions 2 and 6. Similarly, from the application of the DISQUAC (dispersive-quasichemical) model, it is possible to conclude that homocoordination is higher in systems with 3- or 4-methylpyridine than in those involving 2-methylpyridine. Systems including aromatic hydrocarbons are nearly ideal, which seems to indicate that there is no specific interaction in such solutions. Mixtures with 1-alkanols show heterocoordination. This reveals the existence of interactions between unlike molecules, characteristic of alkanol + amine mixtures. Methanol systems show the lowest S{sub CC}(0) values due, partially, to size effects. This explains the observed decrease of homocoordination in such solutions in the order: pyridine > 2-methylpyridine > 2,6-dimethylpyridine. Moreover, as the energies of the OH-N hydrogen bonds are practically independent of the pyridine base considered when mixed with methanol, it suggests that

  6. Binary mixtures of two anionic polysaccharides simulating the rheological properties of oxidised starch

    Science.gov (United States)

    Sikora, Marek; Dobosz, Anna; Adamczyk, Greta; Krystyjan, Magdalena; Kowalski, Stanisław; Tomasik, Piotra; Kutyła-Kupidura, Edyta M.

    2017-01-01

    Modifications of starches are carried out to improve their industrial usefulness. However, the consumers prefer natural products. For this reason, various methods of starch properties modification are applied to replace those requiring the use of chemical reagents. The aim of this study was to determine whether it is possible to use binary pastes, containing normal potato starch and xanthan gum, as substitutes of chemically modified starches (with oxidised starch E 1404 pastes as an example). Flow curves with hysteresis loops, apparent viscosity at constant shear rate of 50 s-1 and in-shear structural recovery test with pre-shearing were applied to study the rheological properties of the pastes. It was found that two anionic hydrocolloids, potato starch and xanthan gum, can form binary systems with thickening properties, provided that their proportions are adequately adjusted. Some of the binary pastes under investigation exhibited rheological properties resembling pastes of starch oxidised with hypochlorite (E 1404). The way of tailoring the binary pastes properties is presented.

  7. Analysis UO2-CeO2 Powder Mixtures by the Binary-ratio Method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The binary-ratio method is a special case in the X-ray fluorescence analysis and is suitable for themixed sample in which contains two compositions. A calibration curve of the analysis line intensity ratioversus concentration ratio is established, and is insensitive to reasonable variations in surface texture. The

  8. Activity of binary mixtures of drospirenone with progesterone and 17α-ethinylestradiol in vitro and in vivo.

    Science.gov (United States)

    Rossier, Nadine Madeleine; Chew, Geraldine; Zhang, Kun; Riva, Francesco; Fent, Karl

    2016-05-01

    Despite potential exposure of aquatic organisms to mixtures of steroid hormones, very little is known on their joint activity in fish. Drospirenone (DRS) is a new synthetic progestin used in contraceptive pills in combination with 17α-ethinylestradiol (EE2). Here we systematically analyzed effects of DRS in binary mixtures with progesterone (P4) and EE2. First, we determined the in vitro activity of single compounds in recombinant yeast assays that express the human progesterone, androgen, or estrogen receptor, followed by determination of mixture activities of DRS and P4, DRS and EE2, as well as medroxyprogesterone acetate (MPA) and dydrogesterone (DDG). Mixtures of DRS and P4, as well as of DRS and EE2 showed additive progestogenic and androgenic activities. However, DDG and MPA showed non-additive progestogenic and androgenic activities. We then analyzed the in vivo activity of single compounds and mixtures of DRS and P4, as well as DRS and EE2, by assessing transcriptional changes of up to 14 selected target genes in zebrafish embryos at 48h post fertilization (hpf), and in eleuthero-embryos at 96hpf and 144hpf. DRS, P4, and EE2 led to significant transcriptional alteration of genes, including those encoding hormone receptors (pgr, esr1), a steroidogenic enzyme (hsd17b3), and estrogenic markers (vtg1, cyp19b), in particular at 144 hpf. In general, DRS showed stronger transcriptional changes than P4. In mixtures of DRS and P4, they were mainly non-additive (antagonistic interaction). In mixtures of DRS and EE2, transcriptional responses of esr1, vtg1 and cyp19b were dominated by EE2, suggesting an antagonistic interaction or independent action. Equi-effective mixtures of DRS and EE2, based on progesterone receptor transcripts, showed antagonistic interactions. Our data suggest that interactions in mixtures assessed in vitro in recombinant yeast cannot be translated to the in vivo situation. The receptor-based responses did not correspond well to the

  9. A nonlinear equation for ionic diffusion in a strong binary electrolyte

    CERN Document Server

    Ghosal, Sandip; 10.1098/rspa.2010.0028

    2012-01-01

    The problem of the one dimensional electro-diffusion of ions in a strong binary electrolyte is considered. In such a system the solute dissociates completely into two species of ions with unlike charges. The mathematical description consists of a diffusion equation for each species augmented by transport due to a self consistent electrostatic field determined by the Poisson equation. This mathematical framework also describes other important problems in physics such as electron and hole diffusion across semi-conductor junctions and the diffusion of ions in plasmas. If concentrations do not vary appreciably over distances of the order of the Debye length, the Poisson equation can be replaced by the condition of local charge neutrality first introduced by Planck. It can then be shown that both species diffuse at the same rate with a common diffusivity that is intermediate between that of the slow and fast species (ambipolar diffusion). Here we derive a more general theory by exploiting the ratio of Debye length...

  10. Application of the Kirkwood-Buff theory of solutions to acetonitrile + amide binary mixtures by using inversion procedure and regular solution theory

    Indian Academy of Sciences (India)

    Anil Kumar Nain

    2009-05-01

    The Kirkwood-Buff (K-B) integrals play an important role in characterizing the intermolecular interactions in liquid mixtures. These are represented by the K-B parameters, AA, BB, and AB, which reflect correlation between like-like and like-unlike species in the mixture. The K-B integrals of binary mixtures of acetonitrile (ACN) with formamide (FA), N,N-dimethylformamide (DMF), N-methylacetamide (NMA) and N,N-dimethylacetamide (DMA) at 298.15 K and at atmospheric pressure have been computed from the experimental data of ultrasonic speed and density. We have used the similar inverse procedure (as proposed by Ben-Naim) to compute the K-B Parameters of the mixtures, in which thermodynamic information on mixtures such as partial molar volumes, isothermal compressibility, and experimental data of partial vapour pressures are used. A new route has been incorporated by using regular solution theory in the computation of excess free energy for obtaining the partial vapour pressures of binary liquid mixtures. The low values of excess entropy ( ≈ 0) obtained for these mixtures indicate the applicability of regular solution theory to these mixtures. The results obtained regarding intermolecular interaction in all the four mixtures under study from this new procedure are in good agreement with those obtained from the trends exhibited by the excess functions of these mixtures.

  11. Comparative Study of Molecular Interactions in Binary Liquid Mixtures of 4 –Methyl-2-pentanoneWith Butan-2-One, Furfuraldehyde, Cyclohexanone At 308 K

    Directory of Open Access Journals (Sweden)

    D. Ubagaramary

    2016-03-01

    Full Text Available Molecular interaction studies using ultrasonic technique in the binary liquid mixtures of 4 –Methyl-2-pentanone With Butan-2-One,Furfuraldehyde and Cyclohexanonehas been carried out at different temperature. Using the measured values of ultrasonic velocity, density and viscosity, acoustical parameters and their excess values are evaluated. From these excess parametersare used to discussing about the nature and strength of the interactions in these binary systems.

  12. Binary Adsorption Equilibrium of Benzene—Water Vapor Mixtures on Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    GAOHuasheng; YEYunchun; 等

    2002-01-01

    Adsorption equilibrium isotherms of benzene in the concentration range of 500-4000mg·m-3 on two commercial activated carbons were obtained using long-column method under 30℃ and different humidity conditions. Results show that the benzene and water vapors have depression effects upon the adsorption of each other and that the unfavorable effect of water vapor resembles its single-component isotherm on activated carbon.A competitive adsorption model was proposed to explore the depression mechanisms of the non-ideal,non-similar binary adsorption systems.A modified polanyi-Dubinin equation was set up to correlate the binary adsorption equilibrium and to calculte the isotherms of benzene on activated carbon in presence of water vapor with considerable precision.

  13. Separation of Binary Mixtures of Propylene and Propane by Facilitated Transport through Silver Incorporated Poly(Ether-Block-Amide Membranes

    Directory of Open Access Journals (Sweden)

    Surya Murali R.

    2015-02-01

    Full Text Available The separation of propylene and propane is a challenging task in petroleum refineries due to the similar molecular sizes and physical properties of two gases. Composite Poly(ether-block-amide (Pebax-1657 membranes incorporated with silver tetra fluoroborate (AgBF4 in concentrations of 0-50% of the polymer weight were prepared by solution casting and solvent evaporation technique. The membranes were characterized by Scanning Electron Microscopy (SEM, Fourier Transform InfraRed (FTIR and wide-angle X-ray Diffraction (XRD to study surface and cross-sectional morphologies, effect of incorporation on intermolecular interactions and degree of crystallinity, respectively. Experimental data was measured with an indigenously built high-pressure gas separation manifold having an effective membrane area of 42 cm2. Permeability and selectivity of membranes were determined for three different binary mixtures of propylene-propane at pressures varying in the range 2-6 bar. Selectivity of C3H6/C3H8 enhanced from 2.92 to 17.22 and 2.11 to 20.38 for 50/50 and 66/34 C3H6+C3H8 feed mixtures, respectively, with increasing loading of AgBF4. Pebax membranes incorporated with AgBF4 exhibit strong potential for the separation of C3H6/C3H8 mixtures in petroleum refineries.

  14. Kinetically driven self-assembly of a binary solute mixture with controlled phase separation via electro-hydrodynamic flow of corona discharge.

    Science.gov (United States)

    Jung, Hee Joon; Huh, June; Park, Cheolmin

    2012-10-21

    This feature article describes a new and facile process to fabricate a variety of thin films of non-volatile binary solute mixtures suitable for high performance organic electronic devices via electro-hydrodynamic flow of conventional corona discharge. Both Corona Discharge Coating (CDC) and a modified version of CDC, Scanning Corona Discharge Coating (SCDC), are based on utilizing directional electric flow, known as corona wind, of the charged uni-polar particles generated by corona discharge between a metallic needle and a bottom plate under a high electric field (5-10 kV cm(-1)). The electric flow rapidly spreads out the binary mixture solution on the bottom plate and subsequently forms a smooth and flat thin film in a large area within a few seconds. In the case of SCDC, the static movement of the bottom electrode on which a binary mixture solution is placed provides further control of thin film formation, giving rise to a film highly uniform over a large area. Interesting phase separation behaviors were observed including nanometer scale phase separation of a polymer-polymer binary mixture and vertical phase separation of a polymer-organic semiconductor mixture. Core-shell type phase separation of either polymer-polymer or polymer-colloidal nanoparticle binary mixtures was also developed with a periodically patterned microstructure when the relative location of the corona wind was controlled to a binary solution droplet on a substrate. We also demonstrate potential applications of thin functional films with controlled microstructures by corona coating to various organic electronic devices such as electroluminescent diodes, field effect transistors and non-volatile polymer memories.

  15. Phase Diagram of Binary Mixture E7:TM74A Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Serafin Delica

    1999-12-01

    Full Text Available Although there are many liquid crystalline materials, difficulty is often experienced in obtaining LCs that are stable and has a wide mesophase range. In this study, mixtures of two different LCs were used to formulate a technologically viable LC operating at room temperature. Nematic E7(BDH and cholesteric TM74A were mixed at different weight ratios at 10% increments. Transition temperatures were determined via Differential Scanning Calorimetry and phase identification was done using Optical Polarizing Microscopy. The phase diagram showed the existence of three different phases for the temperature range of 10-80°C. Mixtures with 0-20% E7 exhibit only the cholesteric-nematic mesophase, which could be due to the mixture's being largely TM74A and its behavior in the temperature range considered is similar to the behavior of pure TM74A. With an increase in the concentration of E7, the smectic phase of the pure cholesteric was enhanced, as seen from the increased transition to the cholesteric-nematic phase and a broader smectic range. The cholesteric-nematic to isotropic transition increased as the nematic concentration increases, following the behavior expected from LC mixtures. For mixtures that are largely nematic (more than 50% E7, the smectic phase has vanished and the cholesteric-nematic phase dominated from 30-60°C.

  16. Mixture

    Directory of Open Access Journals (Sweden)

    Silva-Aguilar Martín

    2011-01-01

    Full Text Available Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity.

  17. Phase Equilibrium Calculation of Mixtures:Use of the SAFT-BACK Equation of State for Binary Systems under Elevated Pressure

    Institute of Scientific and Technical Information of China (English)

    张志禹; 胡中桥; 杨基础; 李以圭

    2002-01-01

    The statistical associating fluid theory (SAFT)-Boublík-Alder-Chen- Kreglewshi(BACK) equation of state is employed to correlate vapor-liquid equilibria of 16 binary mixtures composed of supercritical fluids with other fluids at elevated pressures. The van der Waals mixing rules are used and the binary parameters are adjusted to experimental data. The SAFT-BACK equation of state provides a better correlation of vapor-liquid equilibrium than the original BACK equation. Consequently, the binary parameters computed from the data sets can be used to accurately predict the saturated densities of the vapor and liquid phases.

  18. Radiation-induced graft copolymerization of binary monomer mixture containing acrylonitrile onto polyethylene films

    Science.gov (United States)

    Choi, Seong-Ho; Nho, Young Chang

    2000-04-01

    Graft copolymerization of acrylonitrile (AN)/acrylic acid (AA), acrylonitrile (AN)/methacrylic acid (MA), and acrylonitrile (AN)/glycidyl methacrylate (GMA) onto pre-irradiated polyethylene (PE) films were studied. The effect of reaction conditions such as solvents, additives, and monomer composition on the grafting yields was investigated. The extent of grafting was found to increase with increasing sulfuric acid concentration when sulfuric acid as an additive was added to the grafting solution. In AN/AA mixture, the proportion of acrylonitrile in the copolymer increased with an increasing AN component in feed monomers. On the other hand, in AN/MA mixture, acrylonitrile component in copolymer was very slight in spite of the increase AN component in feed monomers. In the AN/GMA mixture, the proportion of acrylonitrile in the copolymer increased with increasing acrylonitrile component in AN/GMA feed monomer.

  19. Synergic effects in the extraction of paracetamol from aqueous NaCl solution by the binary mixtures of diethyl ether and low molecular weight primary alcohols

    Science.gov (United States)

    Nikolić, G. M.; Živković, J. V.; Atanasković, D. S.; Nikolić, M. G.

    2013-12-01

    Liquid-liquid extraction of paracetamol from aqueous NaCl solutions was performed with diethyl ether, 1-propanol, 1-butanol, isobutanol, 1-pentanol, and binary mixtures diethyl ether/1-propanol, diethyl ether/1-butanol, and diethyl ether/isobutanol. Among the pure solvents investigated in this study best extraction efficacy was obtained with 1-butanol. Synergic effects in the extraction with binary mixtures was investigated and compared with some other systems used for the extraction of poorly extractable compounds. Results obtained in this study may be of both fundamental and practical importance.

  20. Novel binary deep eutectic electrolytes for rechargeable Li-ion batteries based on mixtures of alkyl sulfonamides and lithium perfluoroalkylsulfonimide salts

    Science.gov (United States)

    Geiculescu, O. E.; DesMarteau, D. D.; Creager, S. E.; Haik, O.; Hirshberg, D.; Shilina, Y.; Zinigrad, E.; Levi, M. D.; Aurbach, D.; Halalay, I. C.

    2016-03-01

    Ionic liquids (IL's) were proposed for use in Li-ion batteries (LIBs), in order to mitigate some of the well-known drawbacks of LiPF6/mixed organic carbonates solutions. However, their large cations seriously decrease lithium transference numbers and block lithium insertion sites at electrode-electrolyte interfaces, leading to poor LIB rate performance. Deep eutectic electrolytes (DEEs) (which share some of the advantages of ILs but possess only one cation, Li+), were then proposed, in order to overcome the difficulties associated with ILs. We report herein on the preparation, thermal properties (melting, crystallization, and glass transition temperatures), transport properties (specific conductivity and viscosity) and thermal stability of binary DEEs based on mixtures of lithium bis(trifluoromethane)sulfonimide or lithium bis(fluoro)sulfonimide salts with an alkyl sulfonamide solvent. Promise for LIB applications is demonstrated by chronoamperometry on Al current collectors, and cycling behavior of negative and positive electrodes. Residual current densities of 12 and 45 nA cm-2 were observed at 5 V vs. Li/Li+ on aluminum, 1.5 and 16 nA cm-2 at 4.5 V vs. Li/Li+, respectively for LiFSI and LiTFSI based DEEs. Capacities of 220, 130, and 175 mAh· g-1 were observed at low (C/13 or C/10) rates, respectively for petroleum coke, LiMn1/3Ni1/3Co1/3O2 (a.k.a. NMC 111) and LiAl0.05Co0.15Ni0.8O2 (a.k.a. NCA).

  1. Molecular dynamics simulation of a binary mixture near the lower critical point.

    Science.gov (United States)

    Pousaneh, Faezeh; Edholm, Olle; Maciołek, Anna

    2016-07-07

    2,6-lutidine molecules mix with water at high and low temperatures but in a wide intermediate temperature range a 2,6-lutidine/water mixture exhibits a miscibility gap. We constructed and validated an atomistic model for 2,6-lutidine and performed molecular dynamics simulations of 2,6-lutidine/water mixture at different temperatures. We determined the part of demixing curve with the lower critical point. The lower critical point extracted from our data is located close to the experimental one. The estimates for critical exponents obtained from our simulations are in a good agreement with the values corresponding to the 3D Ising universality class.

  2. NMR investigation of imidazolium-based ionic liquids and their aqueous mixtures.

    Science.gov (United States)

    Cesare Marincola, Flaminia; Piras, Cristina; Russina, Olga; Gontrani, Lorenzo; Saba, Giuseppe; Lai, Adolfo

    2012-04-10

    (1)H and (13)C NMR spectroscopy is employed to investigate the interaction of water with two imidazolium-based ionic liquids (ILs), 1-hexyl-3-methylimidazolium bromide ([C(6)mim]Br) and 1-octyl-3-methylimidazolium bromide ([C(8)mim]Br), at IL concentrations well above the critical aggregation concentration (CAC). The results are compared with those of the neat samples. To this aim, a detailed analysis of the changes in the (1)H chemical shifts, (13)C relaxation parameters, and 2D ROESY data due to the presence of water is performed. The results for both neat ILs are consistent with a packed structure where head-to-head, head-to-tail, and tail-to-tail contacts occur and where the site of maximal mobility restriction is at the polar head. At the lowest investigated water content, the presence of water influences mainly the environment around the IL polar head, slowing down the motional dynamics of the aromatic ring with respect to the alkyl chain. At higher water contents this difference diminishes, the motional freedom of the whole molecule increasing. The presence of ROESY cross-peaks between protons in the polar and apolar IL regions, as well as between protons in non-neighboring alkyl groups, at all investigated water contents suggests that the alkyl tails are not fully segregated in hydrophobic domains, as expected for micelle-like structures.

  3. Proton-transfer reactions of acridine in water-containing ionic-liquid-rich mixtures.

    Science.gov (United States)

    Kumar, Vinod; Pandey, Ashish; Pandey, Siddharth

    2013-12-02

    To assess the potential of ionic liquids (ILs) as a solubilizing media that facilitates proton-transfer reactions, acridine prototropism is investigated using UV/Vis molecular absorbance as well as steady-state and time-resolved fluorescence with different ILs in the presence of a small amount of dilute acid or base. It is found that protonation and deprotonation of acridine, when dissolved in different ILs, can be triggered by the addition of a small amount of dilute aqueous HCl and NaOH, respectively, in both the ground and excited states, irrespective of the identity of the IL. However, the amount of dilute acid/base needed to protonate/deprotonate acridine dissolved in different ILs is found to vary from one IL to another. Steady-state fluorescence measurements also imply the presence of interactions between the acidic proton(s) of IL cation and excited acridine. The interconversion of neutral and protonated acridine, as well as the presence of a weakly fluorescent complex between excited acridine and the acidic proton(s) of the IL cation, is further corroborated by the parameters recovered from the fitting of the excited-state intensity-decay data. It is established that ILs as solubilizing media readily support facile proton transfer in both ground and excited states.

  4. Authentication of Nigella sativa Seed Oil in Binary and Ternary Mixtures with Corn Oil and Soybean Oil Using FTIR Spectroscopy Coupled with Partial Least Square

    Directory of Open Access Journals (Sweden)

    Abdul Rohman

    2013-01-01

    Full Text Available Fourier transform infrared spectroscopy (FTIR combined with multivariate calibration of partial least square (PLS was developed and optimized for the analysis of Nigella seed oil (NSO in binary and ternary mixtures with corn oil (CO and soybean oil (SO. Based on PLS modeling performed, quantitative analysis of NSO in binary mixtures with CO carried out using the second derivative FTIR spectra at combined frequencies of 2977–3028, 1666–1739, and 740–1446 cm−1 revealed the highest value of coefficient of determination (, 0.9984 and the lowest value of root mean square error of calibration (RMSEC, 1.34% v/v. NSO in binary mixtures with SO is successfully determined at the combined frequencies of 2985–3024 and 752–1755 cm−1 using the first derivative FTIR spectra with and RMSEC values of 0.9970 and 0.47% v/v, respectively. Meanwhile, the second derivative FTIR spectra at the combined frequencies of 2977–3028 cm−1, 1666–1739 cm−1, and 740–1446 cm−1 were selected for quantitative analysis of NSO in ternary mixture with CO and SO with and RMSEC values of 0.9993 and 0.86% v/v, respectively. The results showed that FTIR spectrophotometry is an accurate technique for the quantitative analysis of NSO in binary and ternary mixtures with CO and SO.

  5. Authentication of Nigella sativa seed oil in binary and ternary mixtures with corn oil and soybean oil using FTIR spectroscopy coupled with partial least square.

    Science.gov (United States)

    Rohman, Abdul; Ariani, Rizka

    2013-01-01

    Fourier transform infrared spectroscopy (FTIR) combined with multivariate calibration of partial least square (PLS) was developed and optimized for the analysis of Nigella seed oil (NSO) in binary and ternary mixtures with corn oil (CO) and soybean oil (SO). Based on PLS modeling performed, quantitative analysis of NSO in binary mixtures with CO carried out using the second derivative FTIR spectra at combined frequencies of 2977-3028, 1666-1739, and 740-1446 cm(-1) revealed the highest value of coefficient of determination (R (2), 0.9984) and the lowest value of root mean square error of calibration (RMSEC, 1.34% v/v). NSO in binary mixtures with SO is successfully determined at the combined frequencies of 2985-3024 and 752-1755 cm(-1) using the first derivative FTIR spectra with R (2) and RMSEC values of 0.9970 and 0.47% v/v, respectively. Meanwhile, the second derivative FTIR spectra at the combined frequencies of 2977-3028 cm(-1), 1666-1739 cm(-1), and 740-1446 cm(-1) were selected for quantitative analysis of NSO in ternary mixture with CO and SO with R (2) and RMSEC values of 0.9993 and 0.86% v/v, respectively. The results showed that FTIR spectrophotometry is an accurate technique for the quantitative analysis of NSO in binary and ternary mixtures with CO and SO.

  6. Smart stability-indicating spectrophotometric methods for determination of binary mixtures without prior separation.

    Science.gov (United States)

    El-Bardicy, Mohammad G; Lotfy, Hayam M; El-Sayed, Mohammad A; El-Tarras, Mohammad F

    2008-01-01

    Ratio subtraction and isosbestic point methods are 2 innovating spectrophotometric methods used to determine vincamine in the presence of its acid degradation product and a mixture of cinnarizine (CN) and nicergoline (NIC). Linear correlations were obtained in the concentration range from 8-40 microg/mL for vincamine (I), 6-22 microg/mL for CN (II), and 6-36 microg/mL for NIC (III), with mean accuracies 99.72 +/- 0.917% for I, 99.91 +/- 0.703% for II, and 99.58 +/- 0.847 and 99.83 +/- 1.039% for III. The ratio subtraction method was utilized for the analysis of laboratory-prepared mixtures containing different ratios of vincamine and its degradation product, and it was valid in the presence of up to 80% degradation product. CN and NIC in synthetic mixtures were analyzed by the 2 proposed methods with the total content of the mixture determined at their respective isosbestic points of 270.2 and 235.8 nm, and the content of CN was determined by the ratio subtraction method. The proposed method was validated and found to be suitable as a stability-indicating assay method for vincamine in pharmaceutical formulations. The standard addition technique was applied to validate the results and to ensure the specificity of the proposed methods.

  7. Evidencing molecular associations in binary liquid mixtures via photothermal measurements of thermophysical parameters

    NARCIS (Netherlands)

    Neamtu, C.; Dadarlat, D.; Chirtoc, M.; Sahraoui, A.H.; Longuemart, S.; Bicanic, D.D.

    2006-01-01

    The back photopyroelectric (PPE) configuration, with opaque sample and thermally thick sample and sensor, was applied in order to obtain room temperature values of the thermal diffusivity of some liquid mixtures. The methodology is based on a sample's thickness scan, and not on a frequency scan as i

  8. Concentration measurement systems with stable solutions for binary gas mixtures using two flowmeters

    Science.gov (United States)

    Youn, Chongho; Kawashima, Kenji; Kagawa, Toshiharu

    2011-06-01

    The previously proposed gas concentration measurement system (Yamazaki et al 2007 Meas. Sci. Technol. 18 2762-8) shows a considerable error for some combinations of gases. The error increases when the system of equations determining mole fractions becomes a mathematically ill-conditioned system. Because the parameters of the equations reflect the material properties of the gases, the current paper considers flowmeters whose flow rate indication does not involve any gas property. This paper firstly illustrates the ill condition for the combination of venturi meter and laminar flowmeters. The paper then discusses the simultaneous measurement of flow rate and mole fractions by flowmeter combinations: an ultrasonic flowmeter and a venturi meter, an ultrasonic flowmeter and a laminar flowmeter. Experiments are conducted for a mixture of argon and air. When a venturi meter and a laminar flowmeter are used, the equations to evaluate the gas mixture ratio become an ill-conditioned system, and hence the evaluated mixture ratio shows a considerable error. On the other hand, the combination of an ultrasonic flowmeter and a laminar flowmeter detects the gas mixture ratio with proper accuracy.

  9. Heat capacities of the mixtures of ionic liquids with methanol at temperatures from 283.15 K to 323.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Waliszewski, Dariusz [Department of Physical Chemistry, University of Lodz, PL-90 236 Lodz (Poland)], E-mail: waliszew@uni.lodz.pl

    2008-02-15

    The molar isobaric heat capacities of (methanol + 1-hexyl-3-methylimidazolium tetrafluoroborate) and (methanol + 1-methyl-3-octylimidazolium tetrafluoroborate) mixtures have been determined over the temperature range from 283.15 K to 323.15 K within the whole composition range. The excess molar heat capacities of investigated mixtures have been fitted to the Redlich-Kister equation at several selected temperatures. Positive deviations from the additivity of molar heat capacities have been observed in both examined systems. The results obtained have been discussed in terms of molecular interactions in binary mixtures.

  10. Gene expression responses in male fathead minnows exposed to binary mixtures of an estrogen and antiestrogen

    Directory of Open Access Journals (Sweden)

    Perkins Edward J

    2009-07-01

    Full Text Available Abstract Background Aquatic organisms are continuously exposed to complex mixtures of chemicals, many of which can interfere with their endocrine system, resulting in impaired reproduction, development or survival, among others. In order to analyze the effects and mechanisms of action of estrogen/anti-estrogen mixtures, we exposed male fathead minnows (Pimephales promelas for 48 hours via the water to 2, 5, 10, and 50 ng 17α-ethinylestradiol (EE2/L, 100 ng ZM 189,154/L (a potent antiestrogen known to block activity of estrogen receptors or mixtures of 5 or 50 ng EE2/L with 100 ng ZM 189,154/L. We analyzed gene expression changes in the gonad, as well as hormone and vitellogenin plasma levels. Results Steroidogenesis was down-regulated by EE2 as reflected by the reduced plasma levels of testosterone in the exposed fish and down-regulation of genes in the steroidogenic pathway. Microarray analysis of testis of fathead minnows treated with 5 ng EE2/L or with the mixture of 5 ng EE2/L and 100 ng ZM 189,154/L indicated that some of the genes whose expression was changed by EE2 were blocked by ZM 189,154, while others were either not blocked or enhanced by the mixture, generating two distinct expression patterns. Gene ontology and pathway analysis programs were used to determine categories of genes for each expression pattern. Conclusion Our results suggest that response to estrogens occurs via multiple mechanisms, including canonical binding to soluble estrogen receptors, membrane estrogen receptors, and other mechanisms that are not blocked by pure antiestrogens.

  11. Thermophysical Properties of Binary Mixtures of Dimethylsulfoxide with 1-Phenylethanone and 1,4-Dimethylbenzene at Various Temperatures

    Directory of Open Access Journals (Sweden)

    Harmandeep Singh Gill

    2014-01-01

    Full Text Available This research article reports the experimental results of the density, viscosity, refractive index, and speed of sound analysis of binary mixtures of dimethylsulfoxide (DMSO + 1-phenylethanone (acetophenone and + 1,4-dimethylbenzene (para-xylene over the whole composition range at 313.15, 318.15, 323.15, and 328.15 K and at atmospheric pressure. The excess molar volumes (VE, viscosity deviations (Δη, excess Gibbs energy of activation (GE, deviations in isentropic compressibility (KSE, deviations in speed of sound (uE, and deviations in the molar refraction (ΔR were calculated from the experimental data. The computed quantities were fitted to the Redlich-Kister equation to derive the coefficients and estimate the standard error values. The viscosities have also been correlated with two, and three-parameter models, that is, Heric correlation, McAllister model, and Grunberg-Nissan correlation, respectively.

  12. Double diffusive unsteady convective micropolar flow past a vertical porous plate moving through binary mixture using modified Boussinesq approximation

    Directory of Open Access Journals (Sweden)

    Isaac Lare Animasaun

    2016-06-01

    Full Text Available The problem of unsteady convective with thermophoresis, chemical reaction and radiative heat transfer in a micropolar fluid flow past a vertical porous surface moving through binary mixture considering temperature dependent dynamic viscosity and constant vortex viscosity has been investigated theoretically. For proper and correct analysis of fluid flow along vertical surface with a temperature lesser than that of the free stream, Boussinesq approximation and temperature dependent viscosity model were modified and incorporated into the governing equations. The governing equations are converted to systems of ordinary differential equations by applying suitable similarity transformations and solved numerically using fourth-order Runge–Kutta method along with shooting technique. The results of the numerical solution are presented graphically and in tabular forms for different values of parameters. Velocity profile increases with temperature dependent variable fluid viscosity parameter. Increase of suction parameter corresponds to an increase in both temperature and concentration within the thin boundary layer.

  13. Using Raman Spectroscopy and ab initio Calculations to Investigate lntermolecular Hydrogen Bonds in Binary Mixture (Tetrahydrofuran+Water)

    Institute of Scientific and Technical Information of China (English)

    WU Nan-nan; OUYANG Shun-li; LI Zuo-wei; LIU Jing-yao; GAO Shu-qin

    2011-01-01

    We analyzed the properties and structures of the hydrogen-bonded complexes of tetrahydrofuran(THF)and water by means of experimental Raman spectra and ab initio calculations.The optimized geometries and vibrational frequencies of the neat THF molecule and its hydrogen-bonded complexes with water(THF/H2O) were calculated at the MP2/6-31 l+G(d,p) level of theory.We found that the intermolecular hydrogen bonds which are formed from the binary mixtures of the neat THF and water with different molar ratios could explain the changes in wavenumber position and linewidth very well.The combination of ab initio calculations and experimental Raman spectral data provides an insight into the hydrogen bonds leading to the concentration dependent changes in the spectral features.

  14. CO2 capture from binary mixture via forming hydrate with the help of tetra-n-butyl ammonium bromide

    Institute of Scientific and Technical Information of China (English)

    Shifeng Li; Shuanshi Fan; Jingqu Wang; Xuemei Lang; Deqing Liang

    2009-01-01

    Hydrate formation rate and separation effect on the capture of CO2 from binary mixture v/a forming hydrate with 5 wt% tetra-n-butyl ammonium bromide (TBAB) solution were studied.The results showed that the induction time was 5 min,and the hydrate formation process pressure of 7.30 MPa.The CO2 recovery was about 45% in the feed pressure range from 4.30 to 7.30 MPa.Under the feed pressure of 4.30 MPa,the maximum separation factor and CO2 concentration in hydrate phase were 7.3 and 38.2 tool%,respectively.The results demonstrated that TBAB accelerated hydrate formation and enriched CO2 in hydrate phase under the gentle condition.

  15. Viscosities and viscosity deviations of binary mixtures of biodiesel + petrodiesel (or n-hexadecane at different temperatures

    Directory of Open Access Journals (Sweden)

    F. M. R. Mesquita

    2012-09-01

    Full Text Available Viscosities of four binaries mixtures [soybean biodiesel + diesel oil (or n-hexadecane and coconut biodiesel + diesel oil (or n-hexadecane] have been determined at T = (293.15, 313.15, 333.15, 353.15, 373.15 K and atmospheric pressure over the entire composition range. Experimental data were fitted to the Andrade equation and the adjustable parameters and the standard deviations between experimental and calculated values were estimated. From the experimental data, the viscosity deviations, , were calculated by using the Redlich - Kister polynomial equation. The comparison between experimental data determined in this work and four predictive methods used for the estimation of viscosities of biodiesel fuels (based on their fatty acid composition is discussed.

  16. Global phase equilibrium calculations: Critical lines, critical end points and liquid-liquid-vapour equilibrium in binary mixtures

    DEFF Research Database (Denmark)

    Cismondi, Martin; Michelsen, Michael Locht

    2007-01-01

    of critical lines. Each calculated point is analysed for stability by means of the tangent plane distance, and the occurrence of an unstable point is used to determine a critical endpoint (CEP). The critical endpoint, in turn, is used as the starting point for constructing the three-phase line. The equations...... for the critical endpoint, as well as for points on the three-phase line, are also solved using Newton's method with temperature, molar volume and composition as the independent variables. The different calculations are integrated into a general procedure that allows us to automatically trace critical lines......, critical endpoints and three-phase lines for binary mixtures with phase diagrams of types from I to V without advance knowledge of the type of phase diagram. The procedure requires a thermodynamic model in the form of a pressure-explicit EOS but is not specific to a particular equation of state. (C) 2006...

  17. Solid-State FTIR Spectroscopic Study of Two Binary Mixtures: Cefepime-Metronidazole and Cefoperazone-Sulbactam

    Directory of Open Access Journals (Sweden)

    Hassan Refat H. Ali

    2017-01-01

    Full Text Available The structural information of the pharmaceuticals and insights on the modes of molecular interactions are very important aspects in drug development. In this work, two cephalosporins and antimicrobial combinations, cefepime-metronidazole and cefoperazone-sulbactam, were studied in the solid state using FTIR spectroscopy for the first time. Quantitation of the studied drugs and their binary mixtures was performed by integrating the peak areas of the characteristic well-resolved bands: υ (C=O band at 1773 cm−1 for cefepime and ring torsion band at 826 cm−1 for metronidazole and υ (C=O band at 1715 cm−1 for cefoperazone and ring torsion band at 1124 cm−1 for sulbactam. The results of this work were compared with the relevant spectrophotometric reported methods. This study provides data that can be used for the preparative process monitoring of the studied drugs in various dosage forms.

  18. Binary Mixtures of Nonyl Phenol with Alkyl Substituted Anilines as Corrosion Inhibitors for Mild Steel in Acidic Medium

    Directory of Open Access Journals (Sweden)

    H. S. Shukla

    2012-01-01

    Full Text Available The present study deals with the evaluation of the corrosion inhibition effectiveness of the two binary mixtures of nonyl phenol (NPH with 2, 4 dimethyl aniline (DMA and 2 ethyl aniline (EA at different concentration ratios (from 1:7 to 7:1 for mild steel in H2SO4 (pH=1 solution by weight loss and potentiodynamic polarization method. Corrosion inhibition ability of the compounds has been tested at different exposure periods (6 h to 24 h and at different temperatures (303 K to 333 K. The binary mixture of NPH and EA (at 7:1 concentration ratio has afforded maximum inhibition (IE% 93.5% at 6 h exposure period and at room temperature. The adsorption of both the inhibitors is found to accord with Temkin adsorption isotherm. Potentiodynamic polarization study reveals that the tested inhibitors are mixed type inhibitor and preferentially act on cathodic areas. Electrochemical impedance study suggests formation of an inhibition layer by the adsorption of the inhibitors on the metal surface. An adsorption model of the inhibitor molecules on the metal surface has been proposed after immersion test in the inhibited acid showed characteristic shift of N-H and O-H bond frequencies towards lower side compared to that of the respective pure samples which indicated the donation of electron pair through N and O atom of the inhibitor molecule in the surface adsorption phenomena. SEM study has revealed formation of semi globular inhibitor products on the metal surface. The comparisons of the protection efficiencies of these compounds according to their relative electron density on the adsorption centre and projected molecular area of the inhibitor molecules have been made.

  19. Abatement of SO2-NOx binary gas mixtures using a ferruginous active absorbent: Part I. Synergistic effects and mechanism.

    Science.gov (United States)

    Han, Yinghui; Li, Xiaolei; Fan, Maohong; Russell, Armistead G; Zhao, Yi; Cao, Chunmei; Zhang, Ning; Jiang, Genshan

    2015-04-01

    A novel ferruginous active absorbent, prepared by fly ash, industrial lime and the additive Fe(VI), was introduced for synchronous abatement of binary mixtures of SO2-NOx from simulated coal-fired flue gas. The synergistic action of various factors on the absorption of SO2 and NOx was investigated. The results show that a strong synergistic effect exists between Fe(VI) dose and reaction temperature for the desulfurization. It was observed that in the denitration process, the synergy of Fe(VI) dose and Ca/(S+N) had the most significant impact on the removal of NO, followed by the synergy of Fe(VI) and reaction temperature, and then the synergy of reaction temperature and flue gas humidity. A scanning electron microscope (SEM) and an accessory X-ray energy spectrometer (EDS) were used to observe the surface characteristics of the raw and spent absorbent as well as fly ash. A reaction mechanism was proposed based on chemical analysis of sulfur and nitrogen species concentrations in the spent absorbent. The Gibbs free energy, equilibrium constants and partial pressures of the SO2-NOx binary system were determined by thermodynamics.

  20. Modelling of volumetric properties of binary and ternary mixtures by CEOS, CEOS/GE and empirical models

    Directory of Open Access Journals (Sweden)

    BOJAN D. DJORDJEVIC

    2007-12-01

    Full Text Available Although many cubic equations of state coupled with van der Waals-one fluid mixing rules including temperature dependent interaction parameters are sufficient for representing phase equilibria and excess properties (excess molar enthalpy HE, excess molar volume VE, etc., difficulties appear in the correlation and prediction of thermodynamic properties of complex mixtures at various temperature and pressure ranges. Great progress has been made by a new approach based on CEOS/GE models. This paper reviews the last six-year of progress achieved in modelling of the volumetric properties for complex binary and ternary systems of non-electrolytes by the CEOS and CEOS/GE approaches. In addition, the vdW1 and TCBT models were used to estimate the excess molar volume VE of ternary systems methanol + chloroform + benzene and 1-propanol + chloroform + benzene, as well as the corresponding binaries methanol + chloroform, chloroform + benzene, 1-propanol + chloroform and 1-propanol + benzene at 288.15–313.15 K and atmospheric pressure. Also, prediction of VE for both ternaries by empirical models (Radojković, Kohler, Jackob–Fitzner, Colinet, Tsao–Smith, Toop, Scatchard, Rastogi was performed.

  1. Thermodynamics and kinetics of binary nucleation in ideal-gas mixtures

    CERN Document Server

    Alekseechkin, Nikolay V

    2015-01-01

    The nonisothermal single-component theory of droplet nucleation (Alekseechkin, 2014) is extended to binary case; the droplet volume V, composition x, and temperature T are the variables of the theory. An approach based on macroscopic kinetics (in contrast to the standard microscopic model of nucleation operating with the probabilities of monomer attachment and detachment) is developed for the droplet evolution and results in the derived droplet motion equations in the space (V,x,T) - equations for V_dot, x_dot, and T_dot. The work W(V,x,T) of the droplet formation is calculated; it is obtained in the vicinity of the saddle point as a quadratic form with diagonal matrix. Also the problem of generalizing the single-component Kelvin equation for the equilibrium vapor pressure to binary case is solved; it is presented here as a problem of integrability of a Pfaffian equation. The equation for is shown to be the first law of thermodynamics for the droplet, which is a consequence of Onsagers reciprocal relations an...

  2. Solubilization of Phenanthrene and Fluorene in Equimolar Binary Mixtures of Gemini/Conventional Surfactants

    Institute of Scientific and Technical Information of China (English)

    Huma Siddiqui; Mohammad Kamil; Manorama Panda; Kabir-ud-Din

    2014-01-01

    abstract This study deals with the enhanced solubilization of polycyclic aromatic hydrocarbons (PAHs) such as phenan-threne (PHE) and fluorene (FLR) in a pure cationic gemini (G6) and three conventional surfactants [polyethylene glycol dodecyl ether (Brij35), cetyltrimethyl ammonium bromide (CTAB) and sodium lauryl sulfate (SDS)] as well as in their equimolar binary combinations (G6-Brij35, G6-CTAB and G6-SDS). Their solubilization efficiency toward PHE and FLR has been quantified in terms of the molar solubilization ratio (MSR) and the micelle-water partition coefficient (Km). The ideality/nonideality of the mixed micelles is discussed with the help of Clint, Rubingh and Rosen's approaches. These theories determine the deviation of experimental critical micelle concen-tration (CMC) values from ideal critical micelle concentration, which was measured by evaluating the interaction parameters (βm andβσ). Negative values ofβm were observed in all the equimolar binary systems, which show synergism in the mixed micelles. Whereas at air/liquid interface synergism was observed in the systems G6-CTAB and G6-Brij35; G6-SDS exhibited an antagonistic effect. The order of MSR and Km was G6-CTAB N G6-Brij35 N G6-SDS for phenanthrene as well as for fluorene.

  3. Assessment of toxic interactions of heavy metals in binary mixtures: A statistical approach

    Science.gov (United States)

    Ince; Dirilgen; Apikyan; Tezcanli; Ustun

    1999-05-01

    Toxicity of zinc, copper, cobalt, and chromium ions and their binary interactions were studied at varying test levels by using a battery of two tests, Microtox and duckweed with Vibrio fisheri and Lemna minor as test organisms, respectively. The type of toxic interaction at each test combination was assessed by a statistical approach based on testing the null hypothesis of "additive toxicity" at 95% confidence level. The interactions were called "antagonistic," "additive," or "synergistic" in accordance with the statistical significance and the sign of the difference between the tested hypothesis and the value of the observed toxicity at the binary test level concerned. In the majority of the combinations studied by the two bioassays, the interactions were of antagonistic nature. Additive toxicity was the next frequently predicted interaction in both test results, the frequency being much higher in Microtox responses than in those of duckweed. Finally, synergism was found to be a rare interaction in Microtox results, but totally unlikely in duckweed within the selected test combinations.

  4. Deriving binary phase diagrams for chromonic materials in water mixtures via fluorescence spectroscopy: cromolyn and water.

    Science.gov (United States)

    Van Hecke, Gerald R; Karukstis, Kerry K; Rayermann, Scott

    2015-01-14

    We report here the first example of a new and novel method of determining the binary temperature-composition phase diagram of a chromonic material in water using its intrinsic fluorescence. Disodium cromoglycate, or cromolyn, is an anti-allergy medicine representative of a class of compounds known as the chromonics. We have discovered that cromolyn's fluorescence is very sensitive to the polarity, hence structure, of the phase it exhibits. The fluorescence signal shifts its wavelength maximum and its shape depending on whether the cromolyn is a single phase or in coexisting phases. Since the signal due to individual phases can be identified, the fluorescence signal can reveal the temperature-induced transitions between single phase and phase coexistence regions. By studying such fluorescence data for different compositions, an isobaric temperature-composition phase diagram may be constructed. We present here a phase diagram derived from fluorescence studies that is in agreement with previous determinations using other techniques. Our results suggest that the binary phase diagrams of other intrinsically fluorescent chromonic materials, such as perylene monoimide and bisimide derivatives used in organic optoelectronic devices, solar cells, and light-emitting diodes, can be studied in water using an analogous fluorescence approach.

  5. Investigation of the local structure of mixtures of an ionic liquid with polar molecular species through molecular dynamics: cluster formation and angular distributions.

    Science.gov (United States)

    Carrete, Jesús; Méndez-Morales, Trinidad; Cabeza, Óscar; Lynden-Bell, Ruth M; Gallego, Luis J; Varela, Luis M

    2012-05-24

    In this work, we used molecular dynamics simulations to analyze in detail the spatial distributions of the different constituents in mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate with three polar molecular species: water and two alcohols of different chain lengths (methanol and ethanol). In particular, we report results regarding the influence of the chosen species and its concentration on the formation of ionic and molecular clusters over the whole miscibility range, as well as on the angular distribution of polar molecules around the anion and the cation in these systems. Both analyses showed that addition of a molecular species breaks down the polar network of the pure ionic liquid in clusters whose mean size decreases progressively as more molecules are added. At very high concentrations of the molecular species, the ions are found to be isolated in mixtures with water and methanol, but they tend to form pairs in ethanol. In mixtures with water we identified large clusters that form a water network at very high water concentrations, while at low water concentrations polar molecules tend to form smaller aggregates. In contrast, in mixtures with alkanols there is no evidence of the formation of large alcohol clusters at any concentration. Spatial order in alcohol was also studied by means of the Kirkwood G factor, reaching the conclusion that the angular correlations which appear in pure alcohols due to dipole interactions are destroyed by the ionic liquid, even when present only in tiny amounts.

  6. Poly-(3-hexylthiophene) Aggregate Formation in Binary Solvent Mixtures: An Excitonic Coupling Analysis

    Science.gov (United States)

    Boucher, David; Johnson, Calynn

    2014-03-01

    We have studied the aggregation behavior of P3HT [Mn ~ 28.2 kDa, regioregularity >96 %, PDI ~ 1.3] in 96 solvent mixtures is studied using UV-Vis absorption spectroscopy. We used Hansen solubility parameters (HSPs) and Spano excitonic coupling analyses to identify correlations between the properties of the solvent mixtures and the extent of structural order of the aggregates. It is clear that the identity of the poor solvent used to drive aggregation has a significant impact on the excitonic coupling behavior and, hence, the structural order of the P3HT aggregates. However, solubility parameter theory does not account nor provide a predictive theory for the observed trends. Instead, qualitative arguments based on the nature of the interactions between the solvents and the polythiophene and hexyl side chain motifs are used to rationalize the kinetics of formation and the observed excitonic coupling characteristics of the P3HT aggregates.

  7. Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

    KAUST Repository

    Pan, Yichang

    2012-02-01

    The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed excellent separation performances for a wide range of propylene/propane mixtures. The membrane showed a permeability of propylene up to 200. barrers and a propylene to propane separation factor up to 50 at optimal separation conditions, well surpassing the "upper-bound trade-off" lines of existing polymer and carbon membranes. The experimental data also showed that the membranes had excellent reproducibility, long-term stability and thermal stability. © 2011 Elsevier B.V.

  8. Molecular dynamics simulations of the structure of the graphene-ionic liquid/alkali salt mixtures interface.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Lynden-Bell, Ruth M; Varela, Luis M

    2014-07-14

    We performed molecular dynamics simulations of mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate with lithium tetrafluoroborate and potassium tetrafluoroborate between two charged and uncharged graphene walls, in order to analyze the structure of the well-known formation of layers that takes place on liquids under confinement. For this purpose, we studied the molecular density profiles, free energy profiles for bringing lithium and potassium cations from the bulk mixture to the graphene wall and the orientational distributions of imidazolium rings within the first adsorbed layer as a function of salt concentration and electrode potential. The charge densities in the electrodes were chosen to be zero and ±1 e nm(-2), and the salt molar percentages were %salt = 0, 10 and 25. We found that the layered structure extends up to 1-2 nm, where the bulk behaviour is recovered. In addition, whereas for the neutral surface the layers are composed of both ionic species, increasing the electrode potential, the structure changes to alternating cationic and anionic layers leading to an overcompensation of the charge of the previous layer. We also calculated the distribution of angles of imidazolium rings near neutral and charged graphene walls, finding a limited influence of the added salt. In addition, the average tilt of the imidazolium ring within the first layer goes from 36° with respect to a normal vector to the uncharged graphene wall to 62° in the presence of charged walls. The free energy profiles revealed that lithium and potassium ions are adsorbed on the negative surface only for the highest amount of salt, since the free energy barriers for approaching this electrode are considerably higher than kBT.

  9. A combined ultrasonic flow meter and binary vapour mixture analyzer for the ATLAS silicon tracker

    CERN Document Server

    Bates, R; Berry, S; Berthoud, J; Bitadze, A; Bonneau, P; Botelho-Direito, J; Bousson, N; Boyd, G; Bozza, G; Da Riva, E; Degeorge, C; DiGirolamo, B; Doubek, M; Giugni, D; Godlewski, J; Hallewell, G; Katunin, S; Lombard, D; Mathieu, M; McMahon, S; Nagai, K; Perez-Rodriguez, E; Rossi, C; Rozanov, A; Vacek, V; Vitek, M; Zwalinski, L

    2013-01-01

    An upgrade to the ATLAS silicon tracker cooling control system may require a change from C3F8 (octafluoro-propane) evaporative coolant to a blend containing 10-25% of C2F6 (hexafluoro-ethane). Such a change will reduce the evaporation temperature to assure thermal stability following radiation damage accumulated at full LHC luminosity. Central to this upgrade is a new ultrasonic instrument in which sound transit times are continuously measured in opposite directions in flowing gas at known temperature and pressure to deduce the C3F8/C2F6 flow rate and mixture composition. The instrument and its Supervisory, Control and Data Acquisition (SCADA) software are described in this paper. Several geometries for the instrument are in use or under evaluation. An instrument with a pinched axial geometry intended for analysis and measurement of moderate flow rates has demonstrated a mixture resolution of 3.10-3 for C3F8/C2F6 molar mixtures with 20%C2F6, and a flow resolution of 2% of full scale for mass flows up to 30gs-...

  10. Tracing the origins of transient overshoots for binary mixture diffusion in microporous crystalline materials.

    Science.gov (United States)

    Krishna, Rajamani

    2016-06-21

    Separation of mixtures using microporous crystalline materials is normally achieved by exploiting differences in the adsorption strengths of the constituent species. The focus of the current investigation is on diffusion-selective separations that exploit differences in intra-crystalline diffusivities of guest molecules. A number of experimental investigations report overshoots in intra-crystalline loadings of the more mobile species during transient mixture uptake. Analogous overshoots in fluxes occur for mixture permeation across thin microporous membrane layers. The attainment of supra-equilibrium loadings is a common characteristic of diffusion-selective separations; this allows the over-riding of adsorption selectivities. The primary objective of the current investigation is to demonstrate that the Maxwell-Stefan diffusion formulation, using chemical potential gradients as driving forces, is capable of providing a quantitative description of the temporal and spatial overshoots found in diverse experimental studies. The origins of the overshoots can be traced to thermodynamic coupling effects that emanate from sizable off-diagonal contributions of the matrix of thermodynamic correction factors. If thermodynamic coupling effects are neglected, the overshoots are not realized. It is also demonstrated that while the transport of the more mobile partner is uphill of its loading gradient, its transport is downhill the gradient of its chemical potential. The deliberate exploitation of uphill diffusion to achieve difficult separations is highlighted.

  11. Influence of the Dufour effect on convection in binary gas mixtures

    CERN Document Server

    Hollinger, S; Hollinger, St.

    1995-01-01

    Linear and nonlinear properties of convection in binary fluid layers heated from below are investigated, in particular for gas parameters. A Galerkin approximation for realistic boundary conditions that describes stationary and oscillatory convection in the form of straight parallel rolls is used to determine the influence of the Dufour effect on the bifurcation behaviour of convective flow intensity, vertical heat current, and concentration mixing. The Dufour--induced changes in the bifurcation topology and the existence regimes of stationary and traveling wave convection are elucidated. To check the validity of the Galerkin results we compare with finite--difference numerical simulations of the full hydrodynamical field equations. Furthermore, we report on the scaling behaviour of linear properties of the stationary instability.

  12. Binary and Ternary Mixtures of Biopolymers and Water: Viscosity, Refractive Index, and Density

    Science.gov (United States)

    Silva, Bárbara Louise L. D.; Costa, Bernardo S.; Garcia-Rojas, Edwin E.

    2016-08-01

    Biopolymers have been the focus of intense research because of their wide applicability. The thermophysical properties of solutions containing biopolymers have fundamental importance for engineering calculations, as well as for thermal load calculations, energy expenditure, and development of new products. In this work, the thermophysical properties of binary and ternary solutions of carboxymethylcellulose and/or high methoxylation pectin and water at different temperatures have been investigated taking into consideration different biopolymer concentrations. The experimental data related to the thermophysical properties were correlated to obtain empirical models that can describe the temperature-concentration combined effect on the density, refractive index, and dynamic viscosity. From data obtained from the experiments, the density, refractive index, and dynamic viscosity increase with increasing biopolymer concentration and decrease with increasing temperature. The polynomial models showed a good fit to the experimental data and high correlation coefficients (R2ge 0.98) for each studied system.

  13. Custom real-time ultrasonic instrumentation for simultaneous mixture and flow analysis of binary gases in the CERN ATLAS experiment

    CERN Document Server

    Alhroob, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Boyd, G.; Crespo-Lopez, O.; Degeorge, C.; Deterre, C.; Di Girolamo, B.; Doubek, M.; Favre, G.; Hallewell, G.; Hasib, A.; Katunin, S.; Lombard, D.; Madsen, A.; McMahon, S.; Nagai, K.; O'Rourke, A.; Pearson, B.; Robinson, D.; Rossi, C.; Rozanov, A.; Stanecka, E.; Strauss, M.; Vacek, V.; Vaglio, R.; Young, J.; Zwalinski, L.

    2016-01-01

    Custom ultrasonic instruments have been developed for simultaneous monitoring of binary gas mixture and flow in the ATLAS Inner Detector. Sound transit times are measured in opposite directions in flowing gas. Flow rate and sound velocity are respectively calculated from their difference and average. Gas composition is evaluated in real-time by comparison with a sound velocity/composition database, based on the direct dependence of sound velocity on component concentrations in a mixture at known temperature and pressure. Five devices are integrated into the ATLAS Detector Control System. Three instruments monitor coolant leaks into N2 envelopes of the silicon microstrip and Pixel detectors. Resolutions better than ±2×10−5±2×10−5 and ±2×10−4±2×10−4 are seen for C3F8 and CO2 leak concentrations in N2 respectively. A fourth instrument detects sub-percent levels of air ingress into the C3F8 condenser of the new thermosiphon coolant recirculator. Following extensive studies a fifth instrument was b...

  14. The solid-liquid phase diagrams of binary mixtures of even saturated fatty acids differing by six carbon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Mariana C. [LPT, Department of Chemical Process, School of Chemical Engineering, University of Campinas, UNICAMP, P.O. Box 6066, 13083-970, Campinas-SP (Brazil); EXTRAE, Department of Food Engineering, Faculty of Food Engineering, University of Campinas, UNICAMP, P.O. Box 6121, 13083-862, Campinas-SP (Brazil); CICECO, Departamento de Quimica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Rolemberg, Marlus P. [DETQI, Department of Chemical Technology, Federal University of Maranhao (UFMA), Sao Luis, Maranhao (Brazil); Meirelles, Antonio J.A. [EXTRAE, Department of Food Engineering, Faculty of Food Engineering, University of Campinas, UNICAMP, P.O. Box 6121, 13083-862, Campinas-SP (Brazil); Coutinho, Joao A.P. [CICECO, Departamento de Quimica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Kraehenbuehl, M.A., E-mail: mak@feq.unicamp.br [LPT, Department of Chemical Process, School of Chemical Engineering, University of Campinas, UNICAMP, P.O. Box 6066, 13083-970, Campinas-SP (Brazil)

    2009-12-10

    This study was aimed at using the solid-liquid phase diagrams for three binary mixtures of saturated fatty acids, especially the phase transitions below the liquidus line. These mixtures are compounded by caprylic acid (C{sub 8:0}) + myristic acid (C{sub 14:0}), capric acid (C{sub 10:0}) + palmitic acid (C{sub 16:0}), lauric acid (C{sub 12:0}) + stearic acid (C{sub 18:0}), differing by six carbon atoms between carbon chains. The phase diagrams were obtained by differential scanning calorimetry (DSC). The polarized light microscopy was used to complement the characterization for a full grasp of the phase diagram. Not only do these phase diagrams present peritectic and eutectic reactions, but also metatectic reactions, due to solid-solid phase transitions common, in fatty acids. These findings have contributed to the elucidation of the phase behavior of these important biochemical molecules with implications in various industrial production.

  15. Flory-Huggins parameter χ, from binary mixtures of Lennard-Jones particles to block copolymer melts

    Science.gov (United States)

    Chremos, Alexandros; Nikoubashman, Arash; Panagiotopoulos, Athanassios Z.

    2014-02-01

    In this contribution, we develop a coarse-graining methodology for mapping specific block copolymer systems to bead-spring particle-based models. We map the constituent Kuhn segments to Lennard-Jones particles, and establish a semi-empirical correlation between the experimentally determined Flory-Huggins parameter χ and the interaction of the model potential. For these purposes, we have performed an extensive set of isobaric-isothermal Monte Carlo simulations of binary mixtures of Lennard-Jones particles with the same size but with asymmetric energetic parameters. The phase behavior of these monomeric mixtures is then extended to chains with finite sizes through theoretical considerations. Such a top-down coarse-graining approach is important from a computational point of view, since many characteristic features of block copolymer systems are on time and length scales which are still inaccessible through fully atomistic simulations. We demonstrate the applicability of our method for generating parameters by reproducing the morphology diagram of a specific diblock copolymer, namely, poly(styrene-b-methyl methacrylate), which has been extensively studied in experiments.

  16. Separation of species of a binary fluid mixture confined in a channel in presence of a strong transverse magnetic field

    Directory of Open Access Journals (Sweden)

    Sharma Bishwaram

    2012-01-01

    Full Text Available Effects of a transverse magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids confined between two stationary parallel plates are examined. Both the plates are maintained at constant temperatures. It is assumed that one of the components, which is rarer and lighter, is present in the mixture in a very small quantity. The equations governing the motion, temperature and concentration in Cartesian coordinate are solved analytically. The solution obtained for concentration distribution is plotted against the width of the channel for various values of non-dimensional parameters. It is found that the effect of transverse magnetic field is to separate the species of rarer and lighter component by contributing its effect directly to the temperature gradient and the pressure gradient. The effects of increase in the values of Hartmann number, magnetic Reynolds number, barodiffusion number, thermal diffusion number, electric field parameter and the product of Prandtl number and Eckert number are to collect the rarer and lighter component near the upper plate and throw away the heavier component towards the lower plate. The problem discussed here derives its application in the basic fluid dynamics separation processes to separate the rare component of the different isotopes of heavier molecules where electromagnetic method of separation does not work.

  17. The solid-liquid phase diagrams of binary mixtures of consecutive, even saturated fatty acids: differing by four carbon atoms.

    Science.gov (United States)

    Costa, Mariana C; Sardo, Mariana; Rolemberg, Marlus P; Ribeiro-Claro, Paulo; Meirelles, Antonio J A; Coutinho, João A P; Krähenbühl, M A

    2009-01-01

    The complete solid-liquid phase diagrams for four binary mixtures of saturated fatty acids are presented, for the first time, in this work. These mixtures are formed by caprylic acid (C(8:0))+lauric acid (C(12:0)), capric acid (C(10:0))+myristic acid (C(14:0)), lauric acid (C(12:0))+palmitic acid (C(16:0)) and myristic acid (C(14:0))+stearic acid (C(18:0)). The phase diagrams were obtained by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FT-Raman spectrometry and polarized light microscopy were used to complement the characterization for a complete understanding of the phase diagram. All of the phase diagrams here reported show the same global behavior that is far more complex than previously accepted. They present not only peritectic and eutectic reactions, but also metatectic reactions, due to solid-solid phase transitions common in fatty acids, and regions of solid solution not previously reported. This work contributes to the elucidation of the phase behavior of these important biochemical molecules with implications in various industrial applications.

  18. An Energetic Analysis of the Phase Separation in Non-Ionic Surfactant Mixtures: The Role of the Headgroup Structure

    Directory of Open Access Journals (Sweden)

    José Manuel Hierrezuelo

    2014-08-01

    Full Text Available The main goal of this paper was to examine the effect of the hydrophilic surfactant headgroup on the phase behavior of non-ionic surfactant mixtures. Four mixed systems composed of an ethoxylated plus sugar-based surfactants, each having the same hydrophobic tail, were investigated. We found that the hydrophilicity of the surfactant inhibits the tendency of the system to phase separate, which is sensitive to the presence of NaCl. Applying a classical phase separation thermodynamic model, the corresponding energy parameters were evaluated. In all cases, the parameters were found to depend on the type of nonionic surfactant, its concentration in the micellar solution and the presence of NaCl in the medium. The experimental results can be explained by assuming the phase separation process takes place as a result of reduced hydration of the surfactant headgroup caused by a temperature increase. The enthalpy-entropy compensation plot exhibits excellent linearity. We found that all the mixed surfactant systems coincided on the same straight line, the compensation temperature being lower in the presence of NaCl.

  19. Calculation of the T-X phase diagrams for binary mixtures of cholestanyl myristate-cholesteryl myristate and cholestanyl myristate-cholesteryl oleate.

    Science.gov (United States)

    Yurtseven, Hamit; Sen, Sema

    2009-04-01

    T-X phase diagrams of binary mixtures of cholestanyl myristate (CnM)-cholesteryl myristate (CrM) and cholestanyl myristate (CnM)-cholesteryl oleate (CO) are calculated using the mean field theory. We expand the free energies for the phases of cholesteric, smectic, and solid solutions in terms of the order parameters for these binary mixtures (X is the concentration of CrM for CnM-CrM and the concentration of CnM for CnM-CO). From this expansion, we obtain the phase line equations for the transitions among the isotropic liquid, cholesteric, smectic, and solid solutions for both binary mixtures. Taking into account the temperature and concentration dependences of the coefficients in the free energy expansion, we fit our phase line equations to the experimentally measured T-X phase diagrams for these two binary mixtures. Our calculated phase lines coincide with the measured T-X phase diagrams, and the critical behavior of the thermodynamic quantities, including the order parameter, the specific heat, and the susceptibility, can be predicted from the mean field expansions.

  20. Ecotoxicological evaluation of propranolol hydrochloride and losartan potassium to Lemna minor L. (1753) individually and in binary mixtures.

    Science.gov (United States)

    Godoy, Aline A; Kummrow, Fábio; Pamplin, Paulo Augusto Z

    2015-07-01

    Antihypertensive pharmaceuticals, including the beta-blockers, are one of the most detected therapeutic classes in the environment. The ecotoxicity of propranolol hydrochloride and losartan potassium was evaluated, both individually and combined in a binary mixture, by using the Lemna minor growth inhibition test. The endpoints evaluated in the single-pharmaceutical tests were frond number, total frond area and fresh weight. For the evaluation of the mixture toxicity, the selected endpoint was frond number. Water quality criteria values (WQC) were derived for the protection of freshwater and saltwater pelagic communities regarding the effects induced by propranolol and losartan using ecotoxicological data from the literature, including our data. The risks associated with both pharmaceutical effects on non-target organisms were quantified through the measured environmental concentration (MEC)/predicted-no-effect concentration (PNEC) ratios. For propranolol, the total frond area was the most sensitive endpoint (EC50 = 77.3 mg L(-1)), while for losartan there was no statistically significant difference between the endpoints. Losartan is only slightly more toxic than propranolol. Both concentration addition and independent action models overestimated the mixture toxicity of the pharmaceuticals at all the effect concentration levels evaluated. The joint action of both pharmaceuticals showed an antagonistic interaction to L. minor. Derived WQC assumed lower values for propranolol than for losartan. The MEC/PNEC ratios showed that propranolol may pose a risk for the most sensitive aquatic species, while acceptable risks posed by losartan were estimated for most of aquatic matrices. To the authors knowledge these are the first data about losartan toxicity for L. minor.

  1. Formation of H2-He substellar bodies in cold conditions. Gravitational stability of binary mixtures in a phase transition

    Science.gov (United States)

    Füglistaler, A.; Pfenniger, D.

    2016-06-01

    Context. Molecular clouds typically consist of 3/4 H2, 1/4 He and traces of heavier elements. In an earlier work we showed that at very low temperatures and high densities, H2 can be in a phase transition leading to the formation of ice clumps as large as comets or even planets. However, He has very different chemical properties and no phase transition is expected before H2 in dense interstellar medium conditions. The gravitational stability of fluid mixtures has been studied before, but these studies did not include a phase transition. Aims: We study the gravitational stability of binary fluid mixtures with special emphasis on when one component is in a phase transition. The numerical results are aimed at applications in molecular cloud conditions, but the theoretical results are more general. Methods: First, we study the gravitational stability of van der Waals fluid mixtures using linearized analysis and examine virial equilibrium conditions using the Lennard-Jones intermolecular potential. Then, combining the Lennard-Jones and gravitational potentials, the non-linear dynamics of fluid mixtures are studied via computer simulations using the molecular dynamics code LAMMPS. Results: Along with the classical, ideal-gas Jeans instability criterion, a fluid mixture is always gravitationally unstable if it is in a phase transition because compression does not increase pressure. However, the condensed phase fraction increases. In unstable situations the species can separate: in some conditions He precipitates faster than H2, while in other conditions the converse occurs. Also, for an initial gas phase collapse the geometry is essential. Contrary to spherical or filamentary collapses, sheet-like collapses starting below 15 K easily reach H2 condensation conditions because then they are fastest and both the increase of heating and opacity are limited. Conclusions: Depending on density, temperature and mass, either rocky H2 planetoids, or gaseous He planetoids form. H2

  2. Ultrasonic study on molecular interactions in binary mixtures of formamide with 1-propanol or 2-propanol

    Institute of Scientific and Technical Information of China (English)

    Manju Rani; Suman Gahlyan; Ankur Gaur; Sanjeev Maken

    2015-01-01

    Ultrasonic speeds have been measured at 298.15 K and 308.15 K for mixtures of formamide+1-propanol or 2-propanol. For an equimolar mixture, excess molar compressibility follows the sequence of 1-propanol N 2-propanol. The ultrasonic speed data are correlated by various correlations such as Nomoto's relation, van Dael's mixing relation and impedance dependence relation, and analyzed in terms of Jacobson's free length theory and Schaaff's collision factor theory. Excess isentropic compressibility is calculated from ex-perimental ultrasonic speed data and previously reported excess volume data. The excess molar ultrasonic speed and isentropic compressibility values are fitted to Redlich–Kister polynomial equation. Other proper-ties such as molecular association, avallable volume, free volume, and intermolecular free length are also calculated. The excess isentropic compressibility data are also interpreted in terms of graph theoretical ap-proach. The calculated isentropic compressibility values are well consistent with the experimental data. It is found that the interaction between formamide and propanol increases when hydroxyl group attached to a carbon atom has more–CH3 groups.

  3. Phase equilibria study in binary systems (tetra-n-butylphosphonium tosylate ionic liquid + 1-alcohol, or benzene, or n-alkylbenzene).

    Science.gov (United States)

    Domańska, Urszula; Paduszyński, Kamil

    2008-09-04

    Ambient pressure (solid + liquid) equilibria (SLE) and (liquid + liquid) equilibria (LLE) of binary systems--ionic liquid (IL) tetra- n-butylphosphonium p-toluenesulfonate + 1-alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol, or 1-dodecanol), benzene, or n-alkylbenzene (toluene, ethylbenzene, n-propylbenzene)-have been determined by using dynamic method in a broad range of mole fractions and temperatures from 250 to 335 K. For binaries containing alcohol, simple eutectic diagrams were observed with complete miscibility in the liquid phase. Only in the case of system [IL + n-propylbenzene] was mutual immiscibility with an upper critical solution temperature (UCST) with low solubility of the IL in the alcohol and high solubility of the alcohol in the IL detected. The basic thermal properties of pure IL, i.e., melting and glass-transition temperatures as well as enthalpy of melting, have been measured with differential scanning microcalorimetry technique (DSC). Well-known UNIQUAC, Wilson, NRTL, NRTL1, and NRTL2 equations have been fitted to obtain experimental data sets. For the system containing immiscibility gap [IL + n-propylbenzene], parameters of the equations have been derived only from SLE data. As a measure of goodness of correlations, root-mean square deviations of temperature have been used. These experimental results were compared to the previously measured binary systems with tetra- n-butylphosphonium methanesulfonate. Changing anion from methanesulfonate to p-toluenesulfonate decreases solubilities in systems with alcohols and increases the solubilities in binary systems with benzene and alkylbenzenes.

  4. Two-dimensional Turbulence in Symmetric Binary-Fluid Mixtures: Coarsening Arrest by the Inverse Cascade

    CERN Document Server

    Perlekar, Prasad; Pandit, Rahul

    2015-01-01

    We study two-dimensional (2D) binary-fluid turbulence by carrying out an extensive direct numerical simulation (DNS) of the forced, statistically steady turbulence in the coupled Cahn-Hilliard and Navier-Stokes equations. In the absence of any coupling, we choose parameters that lead (a) to spinodal decomposition and domain growth, which is characterized by the spatiotemporal evolution of the Cahn-Hilliard order parameter $\\phi$, and (b) the formation of an inverse-energy-cascade regime in the energy spectrum $E(k)$, in which energy cascades towards wave numbers $k$ that are smaller than the energy-injection scale $k_{inj}$ in the turbulent fluid. We show that the Cahn-Hilliard-Navier-Stokes coupling leads to an arrest of phase separation at a length scale $L_c$, which we evaluate from $S(k)$, the spectrum of the fluctuations of $\\phi$. We demonstrate that (a) $L_c \\sim L_H$, the Hinze scale that follows from balancing inertial and interfacial-tension forces, and (b) $L_c$ is independent, within error bars, o...

  5. Variable permeability effect on convection in binary mixtures saturating a porous layer

    Energy Technology Data Exchange (ETDEWEB)

    Alloui, Z.; Vasseur, P. [University of Montreal, Ecole Polytechnique de Montreal, Montreal, QC (Canada); Bennacer, R. [LEEVAM, University of Cergy, Neuville sur Oise (France)

    2009-06-15

    The Darcy Model with the Boussinesq approximation is used to study natural convection in a shallow porous layer, with variable permeability, filled with a binary fluid. The permeability of the medium is assumed to vary exponentially with the depth of the layer. The two horizontal walls of the cavity are subject to constant fluxes of heat and solute while the two vertical ones are impermeable and adiabatic. The governing parameters for the problem are the thermal Rayleigh number, R{sub T}, the Lewis number, Le, the buoyancy ratio, {phi}, the aspect ratio of the cavity, A, the normalized porosity, {epsilon}, the variable permeability constant, c, and parameter a defining double-diffusive convection (a=0) or Soret induced convection (a=1). For convection in an infinite layer, an analytical solution of the steady form of the governing equations is obtained on the basis of the parallel flow approximation. The onset of supercritical convection, R{sub T}C{sup sub}, or subcritical, R{sub T}C{sup sub}, convection are predicted by the present theory. A linear stability analysis of the parallel flow model is conducted and the critical Rayleigh number for the onset of Hopf's bifurcation is predicted numerically. Numerical solutions of the full governing equations are found to be in excellent agreement with the analytical predictions. (orig.)

  6. Convection in Binary Fluid Mixtures; 1, Extended Traveling Wave and Stationary States

    CERN Document Server

    Barten, W; Kamps, M; Schmitz, R

    1995-01-01

    Nonlinear convection structures are investigated in quantitative detail as a function of Rayleigh number for several negative and positive Soret coupling strengths (separation ratios) and different Lewis and Prandtl numbers characterizing different mixtures. A finite difference method was used to solve the full hydrodynamic field equations in a range of experimentally accessible parameters. We elucidate the important role that the concentration field plays in the nonlinear states of stationary overturning convection (SOC) and of traveling wave (TW) convection. Structural differences in the concentration boundary layers and of the concentration plumes in TW's and SOC's and their physical consequences are discussed. These properties show that the states con- sidered here are indeed strongly nonlinear, as expected from the magnitude of advection and diffusion in the concentration balance. The bifurcation behaviour of the states is analysed using different order parameters such as flow intensity, Nusselt number, ...

  7. Interactions between discontinuities for binary mixture separation problem and hodograph method

    CERN Document Server

    Elaeva, M S; Yu, Zhukov M

    2016-01-01

    The Cauchy problem for first-order PDE with the initial data which have a piecewise discontinuities localized in different spatial points is completely solved. The interactions between discontinuities arising after breakup of initial discontinuities are studied with the help of the hodograph method. The solution is constructed in analytical implicit form. To recovery the explicit form of solution we propose the transformation of the PDEs into some ODEs on the level lines (isochrones) of implicit solution. In particular, this method allows us to solve the Goursat problem with initial data on characteristics. The paper describes a specific problem for zone electrophoresis (method of the mixture separation). However, the method proposed allows to solve any system of two first-order quasilinear PDEs for which the second order linear PDE, arising after the hodograph transformation, has the Riemann-Green function in explicit form.

  8. Three different methods for determination of binary mixture of Amlodipine and Atorvastatin using dual wavelength spectrophotometry

    Science.gov (United States)

    Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeany, Badr A.

    2013-03-01

    Three simple, specific, accurate and precise spectrophotometric methods depending on the proper selection of two wavelengths are developed for the simultaneous determination of Amlodipine besylate (AML) and Atorvastatin calcium (ATV) in tablet dosage forms. The first method is the new Ratio Difference method, the second method is the Bivariate method and the third one is the Absorbance Ratio method. The calibration curve is linear over the concentration range of 4-40 and 8-32 μg/mL for AML and ATV, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Methods are validated according to the ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit. The mathematical explanation of the procedures is illustrated.

  9. Three different spectrophotometric methods manipulating ratio spectra for determination of binary mixture of Amlodipine and Atorvastatin

    Science.gov (United States)

    Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeiny, Badr A.

    2011-12-01

    Three simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed for the simultaneous determination of Amlodipine besylate (AM) and Atorvastatin calcium (AT) in tablet dosage forms. The first method is first derivative of the ratio spectra ( 1DD), the second is ratio subtraction and the third is the method of mean centering of ratio spectra. The calibration curve is linear over the concentration range of 3-40 and 8-32 μg/ml for AM and AT, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Standard deviation is <1.5 in the assay of raw materials and tablets. Methods are validated as per ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit.

  10. Three different methods for determination of binary mixture of Amlodipine and Atorvastatin using dual wavelength spectrophotometry.

    Science.gov (United States)

    Darwish, Hany W; Hassan, Said A; Salem, Maissa Y; El-Zeany, Badr A

    2013-03-01

    Three simple, specific, accurate and precise spectrophotometric methods depending on the proper selection of two wavelengths are developed for the simultaneous determination of Amlodipine besylate (AML) and Atorvastatin calcium (ATV) in tablet dosage forms. The first method is the new Ratio Difference method, the second method is the Bivariate method and the third one is the Absorbance Ratio method. The calibration curve is linear over the concentration range of 4-40 and 8-32 μg/mL for AML and ATV, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Methods are validated according to the ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit. The mathematical explanation of the procedures is illustrated.

  11. Comparative Investigation of the Ionicity of Aprotic and Protic Ionic Liquids in Molecular Solvents by using Conductometry and NMR Spectroscopy.

    Science.gov (United States)

    Thawarkar, Sachin; Khupse, Nageshwar D; Kumar, Anil

    2016-04-01

    Electrical conductivity (σ), viscosity (η), and self-diffusion coefficient (D) measurements of binary mixtures of aprotic and protic imidazolium-based ionic liquids with water, dimethyl sulfoxide, and ethylene glycol were measured from 293.15 to 323.15 K. The temperature dependence study reveals typical Arrhenius behavior. The ionicities of aprotic ionic liquids were observed to be higher than those of protic ionic liquids in these solvents. The aprotic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmIm][BF4 ], displays 100 % ionicity in both water and ethylene glycol. The protic ionic liquids in both water and ethylene glycol are classed as good ionic candidates, whereas in DMSO they are classed as having a poor ionic nature. The solvation dynamics of the ionic species of the ionic liquids are illustrated on the basis of the (1) H NMR chemical shifts of the ionic liquids. The self-diffusion coefficients D of the cation and anion of [HmIm][CH3 COO] in D2 O and in [D6 ]DMSO are determined by using (1) H nuclei with pulsed field gradient spin-echo NMR spectroscopy.

  12. Extraction of S- and N-compounds from the mixture of hydrocarbons by ionic liquids as selective solvents.

    Science.gov (United States)

    Gabrić, Beata; Sander, Aleksandra; Cvjetko Bubalo, Marina; Macut, Dejan

    2013-01-01

    Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation.

  13. Extraction of S- and N-Compounds from the Mixture of Hydrocarbons by Ionic Liquids as Selective Solvents

    OpenAIRE

    Beata Gabrić; Aleksandra Sander; Marina Cvjetko Bubalo; Dejan Macut

    2013-01-01

    Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene...

  14. Development of a New Binary Solvent System Using Ionic Liquids as Additives to Improve Rotenone Extraction Yield from Malaysia Derris sp.

    Directory of Open Access Journals (Sweden)

    Zetty Shafiqa Othman

    2015-01-01

    Full Text Available Rotenone is one of the prominent insecticidal isoflavonoid compounds which can be isolated from the extract of Derris sp. plant. Despite being an effective compound in exterminating pests in a minute concentration, procuring a significant amount of rotenone in the extracts for commercialized biopesticides purposes is a challenge to be attained. Therefore, the objective of this study was to determine the best ionic liquid (IL which gives the highest yield of rotenone. The normal soaking extraction (NSE method was carried out for 24 hrs using five different types of binary solvent systems comprising a combination of acetone and five respective ionic liquids (ILs of (1 [BMIM] Cl; (2 [BMIM] OAc; (3 [BMIM] NTf2; (4 [BMIM] OTf; and (5 [BMPy] Cl. Next, the yield of rotenone, % (w/w, and its concentration (mg/mL in dried roots were quantitatively determined by means of RP-HPLC and TLC. The results showed that a binary solvent system of [BMIM] OTf + acetone was the best solvent system combination as compared to other solvent systems (P<0.05. It contributed to the highest rotenone content of 2.69 ± 0.21% (w/w (4.04 ± 0.34 mg/mL at 14 hrs of exhaustive extraction time. In conclusion, a combination of the ILs with a selective organic solvent has been proven to increase a significant amount of bioactive constituents in the phytochemical extraction process.

  15. High-strength magnetically switchable plasmonic nanorods assembled from a binary nanocrystal mixture

    Science.gov (United States)

    Zhang, Mingliang; Magagnosc, Daniel J.; Liberal, Iñigo; Yu, Yao; Yun, Hongseok; Yang, Haoran; Wu, Yaoting; Guo, Jiacen; Chen, Wenxiang; Shin, Young Jae; Stein, Aaron; Kikkawa, James M.; Engheta, Nader; Gianola, Daniel S.; Murray, Christopher B.; Kagan, Cherie R.

    2016-11-01

    Next-generation 'smart' nanoparticle systems should be precisely engineered in size, shape and composition to introduce multiple functionalities, unattainable from a single material. Bottom-up chemical methods are prized for the synthesis of crystalline nanoparticles, that is, nanocrystals, with size- and shape-dependent physical properties, but they are less successful in achieving multifunctionality. Top-down lithographic methods can produce multifunctional nanoparticles with precise size and shape control, yet this becomes increasingly difficult at sizes of ∼10 nm. Here, we report the fabrication of multifunctional, smart nanoparticle systems by combining top-down fabrication and bottom-up self-assembly methods. Particularly, we template nanorods from a mixture of superparamagnetic Zn0.2Fe2.8O4 and plasmonic Au nanocrystals. The superparamagnetism of Zn0.2Fe2.8O4 prevents these nanorods from spontaneous magnetic-dipole-induced aggregation, while their magnetic anisotropy makes them responsive to an external field. Ligand exchange drives Au nanocrystal fusion and forms a porous network, imparting the nanorods with high mechanical strength and polarization-dependent infrared surface plasmon resonances. The combined superparamagnetic and plasmonic functions enable switching of the infrared transmission of a hybrid nanorod suspension using an external magnetic field.

  16. Separation of a binary mixture of pesticides in fruits using a flow-through optosensor.

    Science.gov (United States)

    Llorent-Martínez, E J; Delgado-Blanca, I; Ruiz-Medina, A; Ortega-Barrales, P

    2013-10-15

    A flow-through optosensor is here proposed for the determination of mixtures of two widely used pesticides, carbendazim and o-phenylphenol, in fruits. The pesticides are separated on-line using an additional amount of solid support, C18 silica gel, in the flow-through cell. The resolution is performed due to the different retention/desorption kinetics of the analytes when interacting with the C18 microbeads. Therefore, both separation and determination are integrated in the same cell, considerably simplifying the system. In addition, the use of Sequential Injection Analysis provides a high degree of automation and minimum wastes generation. After the analytes are separated, their native fluorescence is measured, obtaining linearity in the 2.0-30 and 1.1-20 mg kg(-1) ranges for carbendazim and o-phenylphenol. The detection limits are 0.60 and 0.33 mg kg(-1) for carbendazim and o-phenylphenol respectively. The proposed method fulfills the maximum residue limits (MRLs) established in Europe and USA for these pesticides in cherries, pineapple, and mango: 5-10 mg kg(-1). In order to demonstrate the suitability of the method, several samples have been analyzed and the obtained results compared with a chromatographic method.

  17. Predicting the vapor-liquid equilibrium of hydrocarbon binary mixtures and polymer solutions using predetermined pure component parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Sang Kyu [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: ycbae@hanyang.ac.kr [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer We have developed a close-packed lattice model for chain-like molecules. Black-Right-Pointing-Pointer The chain length dependence determined from Monte-Carlo simulation results were used. Black-Right-Pointing-Pointer To consider the volume effect, hole theory and two mixing steps were used. Black-Right-Pointing-Pointer A lattice fluid equation of state (LF-EoS) is presented for VLE of hydrocarbon mixtures. Black-Right-Pointing-Pointer Correlation of pure polymer solutions data with use of the LF-EoS. - Abstract: In our previous work, a new close-packed lattice model was developed for multi-component system of chain fluids with taking the chain length dependence from Monte-Carlo (MC) simulation results into account. In this work, we further extend this model to describe pressure, volume and temperature (PVT) properties, such as vapor-liquid equilibrium (VLE). To consider the effect of pressure on the phase behavior, the volume change effect is taken into account by introducing holes into the incompressible lattice model with two mixing steps. The corresponding new lattice fluid equation of state (LF-EoS) is applied to predict the thermodynamic properties of pure and binary mixtures of hydrocarbons as well as pure polymer solutions. The results of the proposed model are compared to other predictive approaches based on VLE calculations using predetermined pure model parameters without further adjustment. Thermodynamic properties predicted using the method developed in this work are consistent with the experimental data.

  18. A flexible approach for the analysis of rare variants allowing for a mixture of effects on binary or quantitative traits.

    Directory of Open Access Journals (Sweden)

    Geraldine M Clarke

    Full Text Available Multiple rare variants either within or across genes have been hypothesised to collectively influence complex human traits. The increasing availability of high throughput sequencing technologies offers the opportunity to study the effect of rare variants on these traits. However, appropriate and computationally efficient analytical methods are required to account for collections of rare variants that display a combination of protective, deleterious and null effects on the trait. We have developed a novel method for the analysis of rare genetic variation in a gene, region or pathway that, by simply aggregating summary statistics at each variant, can: (i test for the presence of a mixture of effects on a trait; (ii be applied to both binary and quantitative traits in population-based and family-based data; (iii adjust for covariates to allow for non-genetic risk factors and; (iv incorporate imputed genetic variation. In addition, for preliminary identification of promising genes, the method can be applied to association summary statistics, available from meta-analysis of published data, for example, without the need for individual level genotype data. Through simulation, we show that our method is immune to the presence of bi-directional effects, with no apparent loss in power across a range of different mixtures, and can achieve greater power than existing approaches as long as summary statistics at each variant are robust. We apply our method to investigate association of type-1 diabetes with imputed rare variants within genes in the major histocompatibility complex using genotype data from the Wellcome Trust Case Control Consortium.

  19. Volumetric and transport properties of binary liquid mixtures of N-methylacetamide with lactones at temperatures (303.15 to 318.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Boodida, Sathyanarayana; Bachu, Ranjith Kumar; Patwari, Murali Krishna [Department of Chemistry, Kakatiya University, Warangal 506 009 (India); Nallani, Satyanarayana [Department of Chemistry, Kakatiya University, Warangal 506 009 (India)], E-mail: ns_narayana@yahoo.com

    2008-09-15

    The values of density ({rho}), viscosity ({eta}) and speed of sound (u) have been measured for binary liquid mixtures of {gamma}-butyrolactone (GBL), {delta}-valerolactone (DVL), and {epsilon}-caprolactone (ECL) with N-methylacetamide (NMA) over the whole composition range at T = (303.15 to 318.15) K and atmospheric pressure. From these data, excess molar volume (V{sup E}), deviation in viscosity ({delta}{eta}), and deviation in isentropic compressibility ({delta}{kappa}{sub s}), are calculated. The results are fitted to a Redlich-Kister type polynomial equation to derive binary coefficients and standard deviations.

  20. Electrochemical and spectroscopic study of Zn(ii) coordination and Zn electrodeposition in three ionic liquids with the trifluoromethylsulfonate anion, different imidazolium ions and their mixtures with water.

    Science.gov (United States)

    Liu, Zhen; El Abedin, Sherif Zein; Endres, Frank

    2015-06-28

    In this paper we report on the use of three ionic liquids, 1-methylimidazolium trifluoromethylsulfonate ([MIm]TfO), 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO) and 1-ethyl-2,3-dimethylimidazolium trifluoromethylsulfonate ([EMMIm]TfO) containing zinc trifluoromethylsulfonate as electrolytes for zinc electrodeposition. By varying the cations from [MIm](+)via [EMIm](+) to [EMMIm](+), the vibrational band in the Far-IR spectra below 200 cm(-1), characterizing the cation-anion interaction, is shifted to lower wavenumbers, which suggests that the interaction between cations and anions is arranged in order of [MIm]TfO > [EMIm]TfO > [EMMIm]TfO. The coordination of Zn(2+) ions in these electrolytes was investigated by Raman spectroscopy. The Raman spectra show obvious differences in terms of the solvation of Zn(2+) ions in the dried electrolytes. The average number of TfO(-) anions bound to each Zn(2+) ion is lower in [MIm]TfO than in [EMIm]TfO and in [EMMIm]TfO, respectively. In ionic liquid-water mixtures, aqueous zinc species were formed in all cases. The differences in zinc species present in the electrolytes should have an influence on their electrochemical behavior and on the morphology of the deposits. In dried ionic liquids, the cyclic voltammograms reveal that the potentials for the deposition of zinc were shifted to more negative values by varying the cations, while in ionic liquid-water mixtures, the deposition of zinc occurs at almost the same potential. The SEM and XRD results show that the surface morphology, crystal shape and size as well as crystallographic orientation of the deposits are markedly affected by varying the cations of the ionic liquids.

  1. Molecular dynamics studies on liquid-phase dynamics and structures of four different fluoropropenes and their binary mixtures with R-32 and CO2.

    Science.gov (United States)

    Raabe, Gabriele

    2014-01-01

    Fluoropropenes such as R-1234yf or R-1234ze(E) have attracted attention as low GWP (global warming potential) refrigerants, both as pure compounds but also to an increasing extent as components in refrigerant blends. In our earlier work [Raabe, G.; Maginn, E. J. J. Phys. Chem. B 2010, 114, 10133-10142 and Raabe, G. J. Phys. Chem. B 2012, 116, 5744-5751], we have introduced a transferable force field for different fluoropropene compounds. This molecular model has already been applied for predictive molecular simulation studies on the vapor-liquid phase equilibria in binary mixtures of the tetrafluoropropenes R-1234yf or R-1234ze(E) with the difluoromethane R-32 and CO2. In this work we present molecular dynamics simulations on the liquid phase properties of the pure fluoropropenes R-1234yf, R-1234ze, R-1234ze(E), and R-1216 and their binary mixtures with CO2 and R-32. Our study covers temperatures from 273 to 313 K, pressures up to 3.5 MPa, and different mixture compositions. We provide predictions on the densities and transport properties of the pure compounds and the binary mixtures to complement experimental data. Additionally, we have analyzed radial and spatial distribution functions in the systems to gain insight into their microscopic structures and preferred interaction sites.

  2. Effects of binary mixtures of benzo[a]pyrene, arsenic, cadmium, and lead on oxidative stress and toxicity in HepG2 cells.

    Science.gov (United States)

    Muthusamy, Sasikumar; Peng, Cheng; Ng, Jack C

    2016-12-01

    Mixed contamination of benzo[a]pyrene (B[a]P), arsenic (As), cadmium (Cd), and lead (Pb) is a major environmental and human health concern. The mixture toxicity data on these co-contaminants are important for their risk assessment. In this study, we have determined the mixture toxicity of As, Cd and Pb, and B[a]P with As, Cd or Pb in HepG2 cells. The binary mixtures of Cd + As, Cd + Pb and As + Pb and B[a]P + metals (B[a]P + As, B[a]P + Cd and B[a]P + Pb) were evaluated for their interaction on the cytotoxicity using the MTS assay. A full factorial design (4 × 5) was used to determine the interaction toxicity and all the six mixtures showed significant interaction on the cytotoxicity. We further investigated the role of oxidative stress (reactive oxygen species (ROS) generation) and antioxidant defense mechanism (total glutathione (GSH) level) with the observed cytotoxicity. The mixtures of metals reduced the total GSH level and increased the ROS generation, respectively. In the case of mixtures of B[a]P and metals, both total GSH level and ROS generation were increased. Overall, the binary mixtures of metals and B[a]P with metals caused a dose dependent toxicity to HepG2 cells. The results also showed a significant contribution of oxidative stress to the observed toxicity and the potential protective role of the total GSH level against this mixture toxicity. The findings of interaction between B[a]P and metals might have an impact on the potential human health risk of this mixtures at contaminated sites.

  3. Modeling of columnar and equiaxed solidification of binary mixtures; Modelisation de la solidification colonnaire et equiaxe de melanges binaires

    Energy Technology Data Exchange (ETDEWEB)

    Roux, P

    2005-12-15

    This work deals with the modelling of dendritic solidification in binary mixtures. Large scale phenomena are represented by volume averaging of the local conservation equations. This method allows to rigorously derive the partial differential equations of averaged fields and the closure problems associated to the deviations. Such problems can be resolved numerically on periodic cells, representative of dendritic structures, in order to give a precise evaluation of macroscopic transfer coefficients (Drag coefficients, exchange coefficients, diffusion-dispersion tensors...). The method had already been applied for a model of columnar dendritic mushy zone and it is extended to the case of equiaxed dendritic solidification, where solid grains can move. The two-phase flow is modelled with an Eulerian-Eulerian approach and the novelty is to account for the dispersion of solid velocity through the kinetic agitation of the particles. A coupling of the two models is proposed thanks to an original adaptation of the columnar model, allowing for undercooling calculation: a solid-liquid interfacial area density is introduced and calculated. At last, direct numerical simulations of crystal growth are proposed with a diffuse interface method for a representation of local phenomena. (author)

  4. Dielectric relaxation studies of binary mixture of β-picoline and methanol using time domain reflectometry at different temperatures

    Science.gov (United States)

    Trivedi, C. M.; Rana, V. A.; Hudge, P. G.; Kumbharkhane, A. C.

    2016-08-01

    Complex permittivity spectra of binary mixtures of varying concentrations of β-picoline and Methanol (MeOH) have been obtained using time domain reflectometry (TDR) technique over frequency range 10 MHz to 25 GHz at 283.15, 288.15, 293.15 and 298.15 K temperatures. The dielectric relaxation parameters namely static permittivity (ɛ0), high frequency limit permittivity (ɛ∞1) and the relaxation time (τ) were determined by fitting complex permittivity data to the single Debye/Cole-Davidson model. Complex nonlinear least square (CNLS) fitting procedure was carried out using LEVMW software. The excess permittivity (ɛ0E) and the excess inverse relaxation time (1/τ)E which contain information regarding molecular structure and interaction between polar-polar liquids were also determined. From the experimental data, parameters such as effective Kirkwood correlation factor (geff), Bruggeman factor (fB) and some thermo dynamical parameters have been calculated. Excess parameters were fitted to the Redlich-Kister polynomial equation. The values of static permittivity and relaxation time increase nonlinearly with increase in the mol-fraction of MeOH at all temperatures. The values of excess static permittivity (ɛ0E) and the excess inverse relaxation time (1/τ)E are negative for the studied β-picoline — MeOH system at all temperatures.

  5. Phase separation in a binary mixture confined between symmetric parallel plates: Capillary condensation transition near the bulk critical point

    Science.gov (United States)

    Yabunaka, Shunsuke; Okamoto, Ryuichi; Onuki, Akira

    2013-03-01

    We investigate phase separation of near-critical binary mixtures between parallel symmetric walls in the strong adsorption regime. We take into account the renormalization effect due to the critical fluctuations using the recent local functional theory [Okamoto and Onuki, J. Chem. Phys.0021-960610.1063/1.3693331 136, 114704 (2012)]. In statics, a van der Waals loop is obtained in the relation between the average order parameter in the film and the chemical potential when the temperature T is lower than the film critical temperature Tcca (in the case of an upper critical solution temperature). In dynamics, we lower T below the capillary condensation line from above Tcca. We calculate the subsequent time development assuming no mass exchange between the film and the reservoir. In the early stage, the order parameter ψ changes only in the direction perpendicular to the walls. For sufficiently deep quenching, such one-dimensional profiles become unstable with respect to the fluctuations varying in the lateral directions. The late-stage coarsening is then accelerated by the hydrodynamic interaction. A pancake domain of the phase disfavored by the walls finally appears in the middle of the film.

  6. Free Energy-Based Coarse-Grained Force Field for Binary Mixtures of Hydrocarbons, Nitrogen, Oxygen, and Carbon Dioxide.

    Science.gov (United States)

    Cao, Fenglei; Deetz, Joshua D; Sun, Huai

    2017-01-23

    The free energy based Lennard-Jones 12-6 (FE-12-6) coarse-grained (CG) force field developed for alkanes1 has been extended to model small molecules of light hydrocarbons (methane, ethane, propane, butane, and isobutane), nitrogen, oxygen, and carbon dioxide. The adjustable parameters of the FE-12-6 potential are determined by fitting against experimental vapor-liquid equilibrium (VLE) curves and heat of vaporization (HOV) data for pure substance liquids. Simulations using the optimized FE-12-6 parameters correctly reproduced experimental measures of the VLE, HOV, density, vapor pressure, compressibility, critical point, and surface tension for pure substances over a wide range of thermodynamic states. The force field parameters optimized for pure substances were tested on methane/butane, nitrogen/decane, and carbon dioxide/decane binary mixtures to predict their vapor-liquid equilibrium phase diagrams. It is found that for nonpolar molecules represented by different sized beads, a common scaling factor (0.08) that reduces the strength of the interaction potential between unlike beads, generated using Lorentz-Berthelot (LB) combination rules, is required to predict vapor-liquid phase equilibria accurately.

  7. Temperature-dependent microwave dielectric relaxation studies of hydrogen bonded polar binary mixtures of propan-1-ol and propionaldehyde.

    Science.gov (United States)

    Vishwam, T; Parvateesam, K; Sreeharisastry, S; Murthy, V R K

    2013-10-01

    The molecular interaction between the polar systems of propan-1-ol and propionaldehyde for various mole fractions at different temperatures were studied by determining the frequency dependent complex dielectric permittivity by using the open-ended coaxial probe technique method in the microwave frequency range from 20 MHz to 20 GHz. The geometries are optimized at HF, B3LYP and MP2 with 6-311G and 6-311G+ basis sets. Dipole moments of the binary mixtures are calculated from the dielectric data using Higasi's method and compared with the theoretical results. Conformational analysis of the formation of hydrogen bond between the propan-1-ol and propionaldehyde is supported by the FT-IR and molecular polarizability calculations. The average relaxation times are calculated from their respective Cole-Cole plots. The activation entropy, activation enthalpy and Kirkwood correlation 'g' factor, excess permittivity (ε(E)), excess inverse relaxation time (1/τ)(E), Bruggeman parameter (f(B)) have also been determined for propan-1-ol and propionaldehyde and the results were correlated.

  8. Dynamic molecular structure and phase diagram of DPPC-cholesterol binary mixtures: a 2D-ELDOR study.

    Science.gov (United States)

    Chiang, Yun-Wei; Costa-Filho, Antonio J; Freed, Jack H

    2007-09-27

    This paper is an application of 2D electron-electron double resonance (2D-ELDOR) with the "full Sc- method" to study model membranes. We obtain and confirm the phase diagram of 1,2-dipalmitoyl-sn-glycerophosphatidylcholine (DPPC)-cholesterol binary mixtures versus temperature and provide quantitative descriptions for its dynamic molecular structure using 2D-ELDOR at the Ku band. The spectra from the end-chain 16-PC spin label in multilamellar phospholipid vesicles are obtained for cholesterol molar concentrations ranging from 0 to 50% and from 25 to 60 degrees C. This phase diagram consists of liquid-ordered, liquid-disordered, and gel phases and phase coexistence regions. The phase diagram is carefully examined according to the spectroscopic evidence, and the rigorous interpretation for the line shape changes. We show that the 2D-ELDOR spectra differ markedly with variation in the composition. The extensive line shape changes in the 2D-plus-mixing-time representation provide useful information to define and characterize the membrane phases with respect to their dynamic molecular structures and to determine the phase boundaries. The homogeneous T2's are extracted from the pure absorption spectra and are used to further distinguish the membrane phases. These results show 2D-ELDOR to be naturally suitable for probing and reporting the dynamic structures of microdomains in model membrane systems and, moreover, providing a very detailed picture of their molecular dynamic structure, especially with the aid of the "full Sc- method".

  9. Kinetics of laser-driven phase separation induced by a tightly focused wave in binary liquid mixtures

    Science.gov (United States)

    Delville, J. P.; Lalaude, C.; Ducasse, A.

    Optical tweezers have recently been used to locally induce liquid-liquid phase separations and to nucleate a single domain inside the trap [H. Masuhara and co-workers, J. Phys. Chem. B 101 (1997) 5900; Langmuir 13 (1997) 414; Bull. Chem. Soc. Japan 69 (1996) 59]. We investigate theoretically these laser-driven transitions in liquid mixtures in a tightly focused wave and analyze their kinetics. After a description of the different quenching processes (electrostriction, thermodiffusion and thermal heating), the droplet growth rate is derived in each case. To illustrate the generality of the purpose, the model is developed for critical binary fluids and the kinetics are discussed in terms of universal behaviors using a comparison with classical uniform quench situations. We also analyze how finite size effects induced by the beam break this dynamic universality. To validate the model, a comparison of the predicted behaviors with recent experimental results is presented. The good agreement illustrates the potentialities of this new application of optical tweezers as micro-physical chemistry tools.

  10. Development of a Binary Mixture Gas Composition Instrument for Use in a Confined High Temperature Environment

    Science.gov (United States)

    Cadell, Seth R.

    , or used to measure the purity of the coolant itself. This work details the efforts conducted to develop such an instrument. While the concept of designing a capacitance sensor to measure a gas mixture is not unique, the application of using a capacitance sensor within a nuclear reactor is a new application. This application requires the development of an instrument that will survive a high temperature nuclear reactor environment and operate at a sensitivity not found in current applications. To prove this technique, instrument prototypes were built and tested in confined environments and at high temperatures. This work discusses the proof of concept testing and outlines an application in the High Temperature Test Facility to increase the operational understanding of the instrument. This work is the first step toward the ultimate outcome of this work, which is to provide a new tool to the gas reactor community allowing real-time measurements of coolant properties within the core.

  11. Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

    Science.gov (United States)

    Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

    2008-01-01

    Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

  12. Effect of genetic algorithm as a variable selection method on different chemometric models applied for the analysis of binary mixture of amoxicillin and flucloxacillin: A comparative study

    Science.gov (United States)

    Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

    2016-03-01

    Different chemometric models were applied for the quantitative analysis of amoxicillin (AMX), and flucloxacillin (FLX) in their binary mixtures, namely, partial least squares (PLS), spectral residual augmented classical least squares (SRACLS), concentration residual augmented classical least squares (CRACLS) and artificial neural networks (ANNs). All methods were applied with and without variable selection procedure (genetic algorithm GA). The methods were used for the quantitative analysis of the drugs in laboratory prepared mixtures and real market sample via handling the UV spectral data. Robust and simpler models were obtained by applying GA. The proposed methods were found to be rapid, simple and required no preliminary separation steps.

  13. Binary Mixtures of SH- and CH3-Terminated Self-Assembled Monolayers to Control the Average Spacing Between Aligned Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Pavelka Laura

    2009-01-01

    Full Text Available Abstract This paper presents a method to control the average spacing between organometallic chemical vapor deposition (OMCVD grown gold nanoparticles (Au NPs in a line. Focused ion beam patterned CH3-terminated self-assembled monolayers are refilled systematically with different mixtures of SH- and CH3-terminated silanes. The average spacing between OMCVD Au NPs is demonstrated systematically to decrease by increasing the v/v% ratio of the thiols in the binary silane mixtures with SH- and CH3-terminated groups.

  14. Isothermal vapour–liquid equilibria in cyclohexanone + dichloroalkane binary mixtures at temperatures from 298.15 to 318.15 K

    Directory of Open Access Journals (Sweden)

    DANA DRAGOESCU

    2011-02-01

    Full Text Available The vapour pressures of binary mixtures of cyclohexanone + dichloroalkane (1,3-dichloropropane and 1,4-dichlorobutane were measured at temperatures between 298.15 and 318.15 K. The vapour pressures vs. liquid phase composition data were used to calculate the activity coefficients of the two components and the excess molar Gibbs energies GE for the mixtures, using the Barker method and the Redlich–Kister, Wilson, NRTL and UNIQUAC equations, taking into account the vapour phase imperfection in terms of the 2nd virial coefficient. No significant difference between the GE values obtained with these equations was observed.

  15. Excess parameters for binary mixtures of ethyl benzoate with 1-propanol, 1-butanol and 1-pentanol at T=303, 308, 313, 318, and 323 K

    Energy Technology Data Exchange (ETDEWEB)

    Sreehari Sastry, S., E-mail: sreeharisastry@yahoo.com [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar, Andhra Pradesh 522 510 (India); Babu, Shaik, E-mail: babu.computers@gmail.com [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar, Andhra Pradesh 522 510 (India); Vishwam, T., E-mail: vishwam@gitam.edu [Department of Engineering Physics, Gitam University, Hyderabad Campus, Andhra Pradesh 502 239 (India); Parvateesam, K., E-mail: kps27031966@gmail.com [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar, Andhra Pradesh 522 510 (India); Sie Tiong, Ha., E-mail: hast@utar.edu.my [Faculty of Science, Department of Chemical Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak (Malaysia)

    2013-07-01

    Various thermo–acoustic parameters, such as excess isentropic compressibility (K{sub s}{sup E}), excess molar volume (V{sup E}), excess free length (L{sub f}{sup E}), excess Gibb's free energy (ΔG{sup *E}), and excess Enthalpy (H{sup E}), have been calculated from the experimentally determined data of density, viscosity and speed of sound for the binary mixtures of ethyl benzoate+1-propanol, or +1-butanol, or +1-pentanol over the entire range of composition at different temperatures (303, 308, 313, 318 and 323 K). The excess functions have been fitted to the Redlich–Kister type polynomial equation. The deviations for excess thermo–acoustic parameters have been explained on the basis of the intermolecular interactions present in these binary mixtures.

  16. Transport properties of a binary mixture of CO2-N2 from the pair potential energy functions based on a semi-empirical inversion method

    Institute of Scientific and Technical Information of China (English)

    Song Bo; Wang Xiao-Po; Yang Fu-Xin; Liu Zhi-Gang

    2012-01-01

    The potential energy surface of a CO2-N2 mixture is determined by using an inversion method,together with a new collision integral correlation [J.Phys.Chem.Ref.Data 19 1179 (1990)].With the new invert potential,the transport properties of CO2-N2 mixture are presented in a temperature range from 273.15 K to 3273.15 K at low density by employing the Chapman-Enskog scheme and the Wang Chang-Uhlenbeck-de Boer theory,consisting of a viscosity coefficient,a thermal conductivity coefficient,a binary diffusion coefficient,and a thermal diffusion factor.The accuracy of the predicted results is estimated to be 2% for viscosity,5% for thermal conductivity,and 10% for binary diffusion coefficient.

  17. Mixtures of room temperature ionic liquid/ethanol solutions as electrolytic media for cerium oxide thin layer electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Lair, V., E-mail: virginie-lair@chimie-paristech.f [Laboratoire d' Electrochimie, Chimie des Interfaces et Modelisation pour l' Energie, LECIME, CNRS UMR 7575-Chimie Paristech (ENSCP)-Paris, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Sirieix-Plenet, J.; Gaillon, L.; Rizzi, C. [UPMC University Paris 06, UMR 7195, Laboratoire de Physicochimie des Electrolytes, Colloides et Sciences Analytiques (PECSA), F-75005 Paris (France); CNRS, UMR 7195, PECSA, F-75005 Paris (France); ESPCI, UMR 7195, PECSA, F-75005 Paris (France); Ringuede, A. [Laboratoire d' Electrochimie, Chimie des Interfaces et Modelisation pour l' Energie, LECIME, CNRS UMR 7575-Chimie Paristech (ENSCP)-Paris, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France)

    2010-12-30

    A cerium oxide thin layer was electrodeposited onto stainless steel, using mixed room temperature ionic liquid (the 1-methyl-3-butylimidazolium bis(trifluoromethyl sulfonyl)imide)/ethanol solutions, as electrolytic medium. The hydrophobic ionic liquid content is one of the main parameters in the morphology control influencing the ceria growth rate and crystallinity. Micro-nano structural properties and electrical behaviour are presented, using XRD, SEM/EDS and impedance spectroscopy, as a function of electrodeposition conditions.

  18. Inertial effects in three-dimensional spinodal decomposition of a symmetric binary fluid mixture: a lattice Boltzmann study

    Science.gov (United States)

    Kendon, Vivien M.; Cates, Michael E.; Pagonabarraga, Ignacio; Desplat, J.-C.; Bladon, Peter

    2001-08-01

    The late-stage demixing following spinodal decomposition of a three-dimensional symmetric binary fluid mixture is studied numerically, using a thermodynamically consistent lattice Boltzmann method. We combine results from simulations with different numerical parameters to obtain an unprecedented range of length and time scales when expressed in reduced physical units. (These are the length and time units derived from fluid density, viscosity, and interfacial tension.) Using eight large (2563) runs, the resulting composite graph of reduced domain size l against reduced time t covers 1 [less, similar] l [less, similar] 105, 10 [less, similar] t [less, similar] 108. Our data are consistent with the dynamical scaling hypothesis that l(t) is a universal scaling curve. We give the first detailed statistical analysis of fluid motion, rather than just domain evolution, in simulations of this kind, and introduce scaling plots for several quantities derived from the fluid velocity and velocity gradient fields. Using the conventional definition of Reynolds number for this problem, Re[phi] = ldl/dt, we attain values approaching 350. At Re[phi] [greater, similar] 100 (which requires t [greater, similar] 106) we find clear evidence of Furukawa's inertial scaling (l [similar] t2/3), although the crossover from the viscous regime (l [similar] t) is both broad and late (102 [less, similar] t [less, similar] 106). Though it cannot be ruled out, we find no indication that Re[phi] is self-limiting (l [similar] t1/2) at late times, as recently proposed by Grant & Elder. Detailed study of the velocity fields confirms that, for our most inertial runs, the RMS ratio of nonlinear to viscous terms in the Navier Stokes equation, R2, is of order 10, with the fluid mixture showing incipient turbulent characteristics. However, we cannot go far enough into the inertial regime to obtain a clear length separation of domain size, Taylor microscale, and Kolmogorov scale, as would be needed to test a

  19. Experimental determination of the (vapor + liquid) equilibrium data of binary mixtures of fatty acids by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matricarde Falleiro, Rafael M. [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Department of Food Engineering (DEA), School of Food Engineering, University of Campinas (UNICAMP), P.O. Box 6121, 13083-862 Campinas, SP (Brazil); Kraehenbuehl, Maria A., E-mail: mak@feq.unicamp.b [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil)

    2010-01-15

    (Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (phi = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C{sub 14:0}) + palmitic acid (C{sub 16:0}), myristic acid (C{sub 14:0}) + stearic acid (C{sub 18:0}), and palmitic acid (C{sub 16:0}) + stearic acid (C{sub 18:0}), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g{sup E} models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.

  20. Development of a Physiologically Based Pharmacokinetic and Pharmacodynamic Model to Determine Dosimetry and Cholinesterase Inhibition for a Binary Mixture of Chlorpyrifos and Diazinon in the Rat

    Energy Technology Data Exchange (ETDEWEB)

    Timchalk, Chuck; Poet, Torka S.

    2008-05-01

    Physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) models have been developed and validated for the organophosphorus (OP) insecticides chlorpyrifos (CPF) and diazinon (DZN). Based on similar pharmacokinetic and mode of action properties it is anticipated that these OPs could interact at a number of important metabolic steps including: CYP450 mediated activation/detoxification, and blood/tissue cholinesterase (ChE) binding/inhibition. We developed a binary PBPK/PD model for CPF, DZN and their metabolites based on previously published models for the individual insecticides. The metabolic interactions (CYP450) between CPF and DZN were evaluated in vitro and suggests that CPF is more substantially metabolized to its oxon metabolite than is DZN. These data are consistent with their observed in vivo relative potency (CPF>DZN). Each insecticide inhibited the other’s in vitro metabolism in a concentration-dependent manner. The PBPK model code used to described the metabolism of CPF and DZN was modified to reflect the type of inhibition kinetics (i.e. competitive vs. non-competitive). The binary model was then evaluated against previously published rodent dosimetry and ChE inhibition data for the mixture. The PBPK/PD model simulations of the acute oral exposure to single- (15 mg/kg) vs. binary-mixtures (15+15 mg/kg) of CFP and DZN at this lower dose resulted in no differences in the predicted pharmacokinetics of either the parent OPs or their respective metabolites; whereas, a binary oral dose of CPF+DZN at 60+60 mg/kg did result in observable changes in the DZN pharmacokinetics. Cmax was more reasonably fit by modifying the absorption parameters. It is anticipated that at low environmentally relevant binary doses, most likely to be encountered in occupational or environmental related exposures, that the pharmacokinetics are expected to be linear, and ChE inhibition dose-additive.

  1. Thermodynamic properties of biofuels: Heat capacities of binary mixtures containing ethanol and hydrocarbons up to 20 MPa and the pure compounds using a new flow calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Maza, David [Research Group TERMOCAL, Thermodynamics and Calibration, Department of Energy, University of Valladolid, Paseo del Cauce 59, E-47011 Valladolid (Spain); Segovia, Jose J., E-mail: josseg@eis.uva.es [Research Group TERMOCAL, Thermodynamics and Calibration, Department of Energy, University of Valladolid, Paseo del Cauce 59, E-47011 Valladolid (Spain); Carmen Martin, M.; Villamanan, Rosa M.; Villamanan, Miguel A. [Research Group TERMOCAL, Thermodynamics and Calibration, Department of Energy, University of Valladolid, Paseo del Cauce 59, E-47011 Valladolid (Spain)

    2011-12-15

    Highlights: > Isobaric heat capacities for heptane, ethanol, and the mixtures of ethanol with heptane and toluene are reported. > They have been measured at 5 pressures over the range (0 to 20) MPa. > An automated flow calorimeter has been developed for the measurements. > The experimental data are fitted to Redlich-Kister equations. > Excess isobaric heat capacities are calculated. - Abstract: Heat capacities are of great significance in the design of new processes and the improvement of existing ones in R and D in production plants as well as the adaptation of new products, in this case, biofuels to their use in a variety of engines and technical devices. An automated flow calorimeter has been developed for the accurate measurement of isobaric heat capacities for pure compounds and mixtures over the range (250 to 400) K and (0 to 20) MPa. In this paper, isobaric heat capacities for heptane, ethanol and the binary mixtures of ethanol with heptane and toluene are reported.

  2. Statistical mechanics of light elements at high pressure. VIII - Thomas-Fermi-Dirac theory for binary mixtures of H with He, C, and O. [in Jupiter planet interiors

    Science.gov (United States)

    Hubbard, W. B.; Macfarlane, J. J.

    1985-01-01

    We present three-dimensional Thomas-Fermi-Dirac calculations of lattice mixing energies of hydrogen with carbon and oxygen atoms, respectively. The results are used to derive effective interatomic potentials for use in liquid-state mixture calculations. We then use the potentials to derive analytic expressions for binary mixture-free energies and to map out the phase diagrams of mixtures of hydrogen with, respectively, helium, carbon, and oxygen, over a pressure range of about 5 to about 10 to the 3rd Mbar. Within this pressure range, all three of the latter elements are found to have unlimited solubility in metallic hydrogen over a temperature range which lies above their pure-element melting temperatures, and which includes likely interior temperatures in the Jovian planets.

  3. Simultaneous determination of propranolol and amiloride in synthetic binary mixtures and pharmaceutical dosage forms by synchronous fluorescence spectroscopy: a multivariate approach

    Science.gov (United States)

    Divya, O.; Shinde, Mandakini

    2013-07-01

    A multivariate calibration model for the simultaneous estimation of propranolol (PRO) and amiloride (AMI) using synchronous fluorescence spectroscopic data has been presented in this paper. Two multivariate techniques, PCR (Principal Component Regression) and PLSR (Partial Least Square Regression), have been successfully applied for the simultaneous determination of AMI and PRO in synthetic binary mixtures and pharmaceutical dosage forms. The SF spectra of AMI and PRO (calibration mixtures) were recorded at several concentrations within their linear range between wavelengths of 310 and 500 nm at an interval of 1 nm. Calibration models were constructed using 32 samples and validated by varying the concentrations of AMI and PRO in the calibration range. The results indicated that the model developed was very robust and able to efficiently analyze the mixtures with low RMSEP values.

  4. Application of solubility parameters in 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol organogel in binary organic mixtures.

    Science.gov (United States)

    Shen, Huahua; Niu, Libo; Fan, Kaiqi; Li, Jingjing; Guan, Xidong; Song, Jian

    2014-08-05

    The gelation behavior of 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol (DMDBS) in binary solvents has been systematically investigated. DMDBS is soluble in DMSO and insoluble in toluene (apolar) or 1-propanol (polar). When DMSO is added to a poor solvent at a certain volume fraction, DMDBS forms an organogel in the mixed solvent. With increasing DMSO content, the minimum gelation concentration increases and the gel-to-sol transition temperature decreases in both systems. However, compared with those in toluene-DMSO mixtures, the gelation ability and thermal stability are better in 1-propanol-DMSO mixtures. Scanning electron microscopy images reveal that the gelators aggregate to form three-dimensional networks. X-ray diffraction shows that the gel has a lamellar structure, which is different from the structure of the precipitate. Fourier transform infrared results reveal H-bonding is the main driving force for self-aggregation and indicate that stronger H-bonding interactions exist between gelators in 1-propanol-DMSO mixtures in contrast with toluene-DMSO mixtures. Attempts have been taken to correlate solvent parameters to gelation behavior in binary solvents. A Teas plot exhibits distinctly different solvent zones in the studied mixed solvents. The polar parameter (δp) indicates a narrow favorable domain for gel formation in the range of 1.64-7.99 MPa(1/2) for some apolar solvent-DMSO mixtures. The hydrogen-bonding parameter (δh) predicts that gelation occurs for values of 14.00-16.50 MPa(1/2) for some polar solvent-DMSO mixtures. The result may have potential applications in predicting the gelation behavior of 1,3:2,4-di-O-benzylidene-d-sorbitol derivatives in mixed solvents.

  5. Ionic liquids/[bmim][N3] mixtures: promising media for the synthesis of aryl azides by SNAr.

    Science.gov (United States)

    D'Anna, Francesca; Marullo, Salvatore; Noto, Renato

    2008-08-15

    The nucleophilic aromatic substitution of some activated aryl or heteroaryl halides has been performed in ionic liquid solution, using the 1-butyl-3-methylimidazolium azide as a nucleophile. The reaction course was studied varying the structures of both substrates and ionic liquids. In particular, in the latter case, the reaction of 2-bromo-5-nitrothiophene was carried out in five different ionic liquids ([bmim][BF 4], [bmim][PF 6], [bmim][NTf 2], [bm 2im][NTf 2], and [bmpyrr][NTf 2]). Finally, for all the substrates considered, a comparison with data obtained in MeOH solution in the presence of NaN 3 was also performed. Data collected indicate that in some cases it is possible to obtain aromatic or heteroaromatic azide derivatives in satisfactory yield by means of a S NAr reaction using [bmim][N 3] as the nucleophile.

  6. Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values

    Science.gov (United States)

    Rasouli, Zolaikha; Ghavami, Raouf

    2016-08-01

    Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD = 0.12], 0.67-23.19 [LOD = 0.13] and 0.73-25.12 [LOD = 0.15] μg mL- 1 for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples.

  7. Physical and chemical properties of binary mixture of N-butylpyridinium nitrate and alcohol%吡啶硝酸盐与醇二元混合体系物化性能研究

    Institute of Scientific and Technical Information of China (English)

    王建英; 梁丽亚; 昝昊搏; 胡永琪

    2012-01-01

    In this paper, MDY-2 electronic densitometer and Germany DCAT21 automatic surface tension meter are used to measure the density and surface tension over the whole concentration range (the molar fraction of ionic liquids in oganic solvents is 0~l) for the binary mixtures of ionic liquids N-butylpyridinium nitrate ([BuPy]NO3) and organic solvents such as metha-nol,ethanol and butanol at the temperature of 298. 15 K. The excess molar volumes VE and the surface tension deviations δγ of binary mixtures {[BuPy]NO3+CH3OH},{[BuPy]NO3+C2H5OH} and {[BuPy]NO3+C4H9OH} are determined. VE and δγ are fitted by using the Redlich-Kister equation. The results show that the excess molar volumes of binary mixtures of {[BuPy]NO3+CH3OH} and {[BuPy]NO3+C2H5()H} are negative over the whole composition range, while the VE of binary mixture {[BuPy]NO3 +C, H9OH} has positive values at low molar fraction of ionic liquid, passing through a maximum and then decreases and becomes negative, showing minimum at higher ionic liquid molar fractioa The surface tension deviations δr of {[BuPy]NO3 +CH3OH} systems are positive, but those of {[BuPy]NO3 +Cz H5OH} and {[BuPy]NO3 +G, H9OH} systems are negative over the entire molar fraction range. It seems that surface tension deviations δγ varys from positive to negative with the increase of alkyl chain length of alcohols.%采用MDY-2电子密度仪和德国DCAT21全自动表面张力仪,在298.15 K下测定了离子液体N-丁基吡啶硝酸盐(N-butylpyridinium nitrate,[BuPy]NO3)与有机溶剂甲醇、乙醇、正丁醇在全浓度范围内(离子液体在有机溶剂中的摩尔分数为0~1)的密度和表面张力,计算了二元体系{[BuPy]NO3+CH3OH},{[BuPy]NO3 +C2H5OH}和{[BuPy] NO3+C4H9OH}的超额摩尔体积VE和表面张力偏差δγ,分别利用Redlich-Kister方程对二元体系的超额摩尔体积VE和表面张力偏差δγ进行了拟合.结果表明:二元体系{[BuPy] NO3 +CH3 OH}和{[BuPy] NO3 +C2 H5 OH}的超额摩尔体积VE

  8. Advantages of ion-based mole fractions for describing phase equilibria in ionic liquids: application to gas solubility.

    Science.gov (United States)

    Longinotti, María Paula; Alvarez, Jorge L; Japas, M Laura

    2009-03-19

    Despite the obvious ionic character of ionic liquids (ILs), previous studies of phase equilibria in these media were formulated implicitly assuming a "molecular" behavior of the ionic solvent. In this work, a more appropriate thermodynamic treatment is applied to describe the solubility of gases in ILs. According to our results, if the concentration is expressed on an ionic basis, solutions of simple gases in ILs display rather small deviations from ideal behavior in wide composition ranges, whereas deviations are larger when the solvent is considered as an anion-cation pair. The present thermodynamic formulation also accounts for the observed solid-liquid phase equilibria of molecular and IL binary mixtures.

  9. Protein remains stable at unusually high temperatures when solvated in aqueous mixtures of amino acid based ionic liquids

    DEFF Research Database (Denmark)

    Chevrot, Guillaume; Fileti, Eudes Eterno; Chaban, Vitaly V.

    2016-01-01

    [EMIM][TRP] (5 mol% in water). Upon analyzing the radius of gyration, the solvent-accessible surface area, root-mean-squared deviations, and inter- and intramolecular hydrogen bonds, we found that the mini-protein remains stable at 30–40 K higher temperatures in aqueous amino acid based ionic liquids...

  10. Excess molar enthalpies of binary mixtures containing 2-decanone or dipentyl ether with long-chain n-alkanes at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Wei-Chen; Lin, Ho-mu [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106-07, Taiwan (China); Lee, Ming-Jer, E-mail: mjlee@mail.ntust.edu.t [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106-07, Taiwan (China)

    2011-04-15

    Research highlights: An isothermal titration calorimeter was used for enthalpy data measurment. The investigated systems are 2-decanone or dipentyl ether with long-chain n-alkanes. The excess enthalpies are all positive over entire composition range. The Patel-Teja equation of state with two parameters gives the best representation. - Abstract: Excess molar enthalpies (H{sup E}) of binary mixtures of 2-decanone or dipentyl ether with n-alkanes, including n-dodecane, n-tetradecane, and n-hexadecane, were measured with an isothermal titration calorimeter (ITC) at T = 298.15 K under atmospheric pressure. All the measured H{sup E} values are positive over the entire range of composition, indicating that all these mixing processes are endothermic. The H{sup E} values varying with composition are found to be nearly symmetric for each binary system. It was also shown that the H{sup E} values follow the order of n-hexadecane > n-tetradecane > n-dodecane at a given composition in either the 2-decanone or dipentyl ether binary systems. An empirical Redlich-Kister equation correlated quantitatively these new H{sup E} data. The Peng-Robinson and the Patel-Teja equations of state, and the NRTL model were also applied to fit the H{sup E} results. Among these tested correlative models, the Patel-Teja equation of state with two adjustable binary interaction parameters generally yielded the best representation.

  11. Isothermal Vapor-liquid Equilibria for the Binary Mixtures of 3-Methylpentane with Ethylene Glycol Monopropyl Ether and Ethylene Glycol Isopropyl Ether

    Energy Technology Data Exchange (ETDEWEB)

    Hyeong, Seonghoon; Jang, Sunghyun; Kim, Hwayong [Seoul National University, Seoul (Korea, Republic of)

    2015-02-15

    Isothermal vapor liquid equilibria for the binary system of 3-methylpentane with ethylene glycol monopropyl ether (C{sub 3}E{sub 1}) and ethylene glycol isopropyl ether (iC{sub 3}E{sub 1}) were measured at 303.15, 318.15, and 333.15K. In our previous work, phase equilibria for the binary system of C{sub 3}E{sub 1} mixtures were investigated according to the chain length of alkane, alcohol or those isomer. But in this study, we discussed the different effect of C{sub 3}E{sub 1} and its isomer, iC{sub 3}E{sub 1}, on the phase equilibria. The measured systems were correlated with a Peng-Robinson equation of state (PR EOS) combined with Wong-Sandler mixing rule for the vapor phase, and NRTL, UNIQUAC, and Wilson activity coefficient models for the liquid phase. All the measured systems showed good agreement with the correlation results. And it was found that the phase equilibria showed very little difference between the iC{sub 3}E{sub 1} mixture system and the C{sub 3}E{sub 1} mixture system.

  12. Measurement and modelization of VLE of binary mixtures of propyl acetate, butyl acetate or isobutyl acetate with methanol at pressure of 0.6 MPa

    Institute of Scientific and Technical Information of China (English)

    P Susial; D Garca; R Susial; YC Clavijo; A Martn

    2016-01-01

    The vapor–liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with meth-anol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng–Robinson equation, a traditional cubic equation of state widely employed in chemical industries, as well as with the perturbed-chain statistical associating fluid PC-SAFT theory of Gross–Sadowski. By correlation of the binary inter-action parameters of these equations, the measured vapor–liquid equilibrium data can be accurately predicted. Thus, this work shows that these models are able to represent the experimental data for systems with associating compounds via hydrogen bonding.

  13. Ionic solvents used in ionic polymer transducers, sensors and actuators

    OpenAIRE

    2004-01-01

    Ionic liquids are incorporated into transducers, actuators or sensors which employ the ionic polymer membranes. The ionic liquids have superior electrochemical stability, low viscosity and low vapor pressure. The transducers, actuators and sensors which utilize ionic polymer membranes solvated with ionic liquids have long term air stability. Superior results are achieved when a conductive powder and ionomer mixture is applied to the ionic polymer membrane to form the electrodes during or afte...

  14. Molecular dynamics analysis of the effect of electronic polarization on the structure and single-particle dynamics of mixtures of ionic liquids and lithium salts

    Science.gov (United States)

    Lesch, Volker; Montes-Campos, Hadrián; Méndez-Morales, Trinidad; Gallego, Luis Javier; Heuer, Andreas; Schröder, Christian; Varela, Luis M.

    2016-11-01

    We report a molecular dynamics study on the effect of electronic polarization on the structure and single-particle dynamics of mixtures of the aprotic ionic liquid 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)-imide ([EMIM][TFSI]) doped with a lithium salt with the same anion at 298 K and 1 bar. In particular, we analyze the effect of electron density fluctuations on radial distribution functions, velocity autocorrelation functions, cage correlation functions, mean-squared displacements, and vibrational densities of states, comparing the predictions of the quantum-chemistry-based Atomistic Polarizable Potential for Liquids, Electrolytes, & Polymers (APPLE&P) with those of its nonpolarizable version and those of the standard non-polarizable Optimized Potentials for Liquid Simulations-All Atom (OPLS-AA). We found that the structure of the mixture is scarcely modified by the fluctuations in electron charge of their constituents, but their transport properties are indeed quite drastically changed, with larger mobilities being predicted for the different species in the bulk mixtures with the polarizable force field. Specifically, the mean-squared displacements are larger for the polarizable potentials at identical time intervals and the intermediate subdiffusive plateaus are greatly reduced, so the transition to the diffusive regime takes place much earlier than in the non-polarizable media. Moreover, the correlations of the added cations inside their cages are weakened out earlier and their vibrational densities of states are slightly red-shifted, reflecting the weakening effect of the electronic polarization on the Coulomb coupling in these dense ionic media. The comparison of OPLS-AA with non-polarizable APPLE&P indicates that adding polarization to OPLS-AA is not sufficient to achieve results close to experiments.

  15. Enhanced toxicity of binary mixtures of Bacillus thuringiensis subsp. israelensis and three essential oil major constituents to wild Anopheles sinensis (Diptera: Culicidae) and Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Chang, Kyu-Sik; Shin, E-Hyun; Yoo, Dae-Hyun; Ahn, Young-Joon

    2014-07-01

    An assessment was made of the toxicity of 12 insecticides and three essential oils as well as Bacillus thuringiensis subsp. israelensis (Bti) alone or in combination with the oil major constituents (E)-anethole (AN), (E) -cinnamaldehyde (CA), and eugenol (EU; 1:1 ratio) to third instars of bamboo forest-collected Aedes albopictus (Skuse) and rice paddy field-collected Anopheles sinensis Wiedemann. An. sinensis larvae were resistant to various groups of the tested insecticides. Based on 24-h LC50 values, binary mixtures of Bti and CA, AN, or EU were significantly more toxic against Ae. albopictus larvae (0.0084, 0.0134, and 0.0237 mg/liter) and An. sinensis larvae (0.0159, 0.0388, and 0.0541 mg/liter) than either Bti (1.7884 and 2.1681 mg/liter) or CA (11.46 and 18.56 mg/liter), AN (16.66 and 25.11 mg/liter), or EU (24.60 and 31.09 mg/liter) alone. As judged by cotoxicity coefficient (CC) and synergistic factor (SF), the three binary mixtures operated in a synergy pattern (CC, 140.7-368.3 and SF, 0.0007-0.0010 for Ae. albopictus; CC, 75.1-245.3 and SF, 0.0008-0.0017 for An. sinensis). Global efforts to reduce the level of highly toxic synthetic insecticides in the aquatic environment justify further studies on the binary mixtures of Bti and essential oil constituents described, in particular CA, as potential larvicides for the control of malaria vector mosquito populations.

  16. Analysis of binary mixtures of aqueous aromatic hydrocarbons with low-phase-noise shear-horizontal surface acoustic wave sensors using multielectrode transducer designs.

    Science.gov (United States)

    Bender, Florian; Mohler, Rachel E; Ricco, Antonio J; Josse, Fabien

    2014-11-18

    The present work investigates a compact sensor system that provides rapid, real-time, in situ measurements of the identities and concentrations of aromatic hydrocarbons at parts-per-billion concentrations in water through the combined use of kinetic and thermodynamic response parameters. The system uses shear-horizontal surface acoustic wave (SH-SAW) sensors operating directly in the liquid phase. The 103 MHz SAW sensors are coated with thin sorbent polymer films to provide the appropriate limits of detection as well as partial selectivity for the analytes of interest, the BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), which are common indicators of fuel and oil accidental releases in groundwater. Particular emphasis is placed on benzene, a known carcinogen and the most challenging BTEX analyte with regard to both regulated levels and its solubility properties. To demonstrate the identification and quantification of individual compounds in multicomponent aqueous samples, responses to binary mixtures of benzene with toluene as well as ethylbenzene were characterized at concentrations below 1 ppm (1 mg/L). The use of both thermodynamic and kinetic (i.e., steady-state and transient) responses from a single polymer-coated SH-SAW sensor enabled identification and quantification of the two BTEX compounds in binary mixtures in aqueous solution. The signal-to-noise ratio was improved, resulting in lower limits of detection and improved identification at low concentrations, by designing and implementing a type of multielectrode transducer pattern, not previously reported for chemical sensor applications. The design significantly reduces signal distortion and root-mean-square (RMS) phase noise by minimizing acoustic wave reflections from electrode edges, thus enabling limits of detection for BTEX analytes of 9-83 ppb (calculated from RMS noise); concentrations of benzene in water as low as ~100 ppb were measured directly. Reliable quantification of BTEX

  17. Miscibility of Two Components in a Binary Mixture of 9-Phenyl Anthracene Mixed with Stearic Acid or Polymethyl Methacrylate at Air-Water Interface

    Institute of Scientific and Technical Information of China (English)

    P. K. Paul; Md. N. Islam; D. Bhattacharjee; S. A. Hussain

    2007-01-01

    We report the miscibility characteristics of two components in a binary mixture of 9-phenyl anthracene (PA) mixed with stearic acid (SA) or polymethyl methacrylate (PMMA). The behaviour of surface pressure versus area per molecule isotherms reveal that the area per molecule decreases systematically with increasing molefractions of PA. The characteristics of areas per molecule versus molefractions and collapse pressure vs molefraction indicate that various interactions involved among the sample and matrix molecules. The interaction scheme is found to change with the change in surface pressure and molefraction of mixing. Scanning electron microscopic study confirms the aggregation of PA molecules in the mixed films.

  18. A Double Diffusive Unsteady MHD Convective Flow Past a Flat Porous Plate Moving through a Binary Mixture with Suction or Injection

    Directory of Open Access Journals (Sweden)

    D. R. V. S. R. K. Sastry

    2013-01-01

    Full Text Available The problem of unsteady magnetohydrodynamic convective flow with radiation and chemical reaction past a flat porous plate moving through a binary mixture in an optically thin environment is considered. The governing boundary layer equations are converted to nonlinear ordinary differential equations by similarity transformation and then solved numerically by MATLAB “bvp4c” routine. The velocity, temperature, and concentration profiles are presented graphically for various values of the material parameters. Also a numerical data for the local skin friction coefficient, the local Nusselt number, and local Sherwood number is presented in tabular forms.

  19. Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water%羰基硫在二乙二醇二乙醚/水二元混合体系中的水解

    Institute of Scientific and Technical Information of China (English)

    李新学; 刘迎新; 魏雄辉

    2005-01-01

    The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

  20. Renewable bio ionic liquids-water mixtures-mediated selective removal of lignin from rice straw: visualization of changes in composition and cell wall structure.

    Science.gov (United States)

    Hou, Xue-Dan; Li, Ning; Zong, Min-Hua

    2013-07-01

    Pretreatment of rice straw by using renewable cholinium amino acids ionic liquids ([Ch][AA] ILs)-water mixtures and the subsequent enzymatic hydrolysis of the residues were conducted in the present work. Of the eight mixtures composed of ILs and water, most were found to be effective for rice straw pretreatment. After pretreatment with 50% ILs-water mixtures, the enzymatic digestion of the lignocellulosic biomass was enhanced significantly, thus leading to satisfactory sugar yields of >80% for glucose and approximately 50% for xylose. To better understand the ILs pretreatment mechanism, confocal laser scanning microscopy combined with immunolabeling and transmission electron microscopy were used to visualize changes in the contents and distribution of two major components--lignin and xylan. The results coupled with changes in chemical structures (infrared spectra) of the substrates indicated occurrence of extensive delignification, especially in cell corner and compound middle lumen of cell walls, which made polysaccharides more accessible to enzymes. This pretreatment process is promising for large-scale application because of the high sugar yields, easy handling, being environmentally benign and highly tolerant to moisture, and significantly reduced cost and energy consumption.

  1. Study on Solution Properties of Binary Mixtures of Some Industrially Important Solvents with Cyclohexylamine and Cyclohexanone at 298.15 K

    Science.gov (United States)

    Roy, Mahendra Nath; Das, Rajesh Kumar; Chanda, Riju

    2010-03-01

    Densities and viscosities were measured for the binary mixtures of cyclohexylamine and cyclohexanone with butyl acetate, butanone, butylamine, tert-butylamine, and 2-butoxyethanol at 298.15 K over the entire composition range. From density data, the values of the excess molar volume ( V E) have been calculated. The experimental viscosity data were correlated by means of the equation of Grunberg-Nissan. The density and viscosity data have been analyzed in terms of some semiempirical viscosity models. The results are discussed in terms of molecular interactions and structural effects. The excess molar volume is found to be either negative or positive depending on the molecular interactions and the nature of the liquid mixtures and is discussed in terms of molecular interactions and structural changes.

  2. A comparative study of the use of powder X-ray diffraction, Raman and near infrared spectroscopy for quantification of binary polymorphic mixtures of piracetam.

    Science.gov (United States)

    Croker, Denise M; Hennigan, Michelle C; Maher, Anthony; Hu, Yun; Ryder, Alan G; Hodnett, Benjamin K

    2012-04-07

    Diffraction and spectroscopic methods were evaluated for quantitative analysis of binary powder mixtures of FII(6.403) and FIII(6.525) piracetam. The two polymorphs of piracetam could be distinguished using powder X-ray diffraction (PXRD), Raman and near-infrared (NIR) spectroscopy. The results demonstrated that Raman and NIR spectroscopy are most suitable for quantitative analysis of this polymorphic mixture. When the spectra are treated with the combination of multiplicative scatter correction (MSC) and second derivative data pretreatments, the partial least squared (PLS) regression model gave a root mean square error of calibration (RMSEC) of 0.94 and 0.99%, respectively. FIII(6.525) demonstrated some preferred orientation in PXRD analysis, making PXRD the least preferred method of quantification.

  3. Theoretical and experimental comparison of the Soret coefficient for water-methanol and water-ethanol binary mixtures

    DEFF Research Database (Denmark)

    Saghir, MZ; Jiang, CG; Derawi, Samer;

    2004-01-01

    In multicomponent. mixtures, a much richer variety of phenomena can occur than in Simple (single-component) fluids. Natural convection in single-component. fluids is due to buoyancy forces caused by temperature gradients. In multicomponent mixtures, buoyancy forces may also be caused by concentra...

  4. Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Amiri, Ali Asghar; Hemmateenejad, Bahram; Safavi, Afsaneh; Sharghi, Hashem; Beni, Ali Reza Salimi [Department of Chemistry, Shiraz University, Shiraz (Iran, Islamic Republic of); Shamsipur, Mojtaba [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of)], E-mail: mshamsipur@yahoo.com

    2007-12-12

    The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter ({pi}{sup *}) and hydrogen-bond basicity ({beta}), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents.

  5. Volumetric behaviour of binary mixtures of (trichloromethane + amines) at temperatures between T = (288.15 and 303.15) K at p = 0.1 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, J.G. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual de Campinas, UNICAMP, C.P. 6145, 13083-970 Campinas, Sao Paulo (Brazil); Torres, R.B. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual de Campinas, UNICAMP, C.P. 6145, 13083-970 Campinas, Sao Paulo (Brazil); Departamento de Engenharia Quimica, Centro Universitario da FEI, 09850-901 Sao Bernardo do Campo, Sao Paulo (Brazil)], E-mail: belchior@fei.edu.br; Volpe, P.L.O. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Estadual de Campinas, UNICAMP, C.P. 6145, 13083-970 Campinas, Sao Paulo (Brazil)

    2008-09-15

    In this work, densities of binary mixtures of {l_brace}trichloromethane (TCM) + n-butylamine (n-BA), or + s-butylamine (s-BA), or + diethylamine (DEA), or + triethylamine (TEA){r_brace} have been determined under atmospheric pressure as a function of composition and temperature using a vibrating-tube densimeter. The temperatures studied were T = (288.15, 293.15, 298.15, and 303.15) K. The excess molar volumes (V{sub m}{sup E}), calculated from density data are negative for all studied systems and the negative deviations follow the sequence: TEA > DEA > s-BA > n-BA. Negative values of V{sub m}{sup E} for binary mixtures were attributed to the formation of hydrogen bonding and of a charge transfer complex between TCM and amines and to structural effects. The partial molar volumes at infinite dilution of each component (V-bar{sub i}{sup oo}) have been determined using three different methods.

  6. Solubility of disodium cytidine 5′-monophosphate in different binary mixtures from 288.15 K to 313.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jin [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); Ma, Tianle; Li, An [National Engineering Technique Research Center for Biotechnology, Nanjing (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing (China); Chen, Xiaochun; Chen, Yong; Xie, Jingjing [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); Wu, Jinglan, E-mail: yinghanjie@njut.edu.cn [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); Ying, Hanjie [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing (China)

    2013-08-10

    Highlights: • Solubility of 5′-CMPNa{sub 2} in different systems was measured the first time. • Experimental data were correlated by CNIBS/Redlich–Kister model and Apelblat model. • Good agreement has been observed between the calculated and the experimental data. • Enthalpy and entropy were calculated by the van’t Hoff equation and Gibbs equation. - Abstract: The solubility of disodium cytidine 5′-monophosphate (5′-CMPNa{sub 2}) in methanol + water and ethanol + water binary mixtures was measured experimentally at the temperatures ranging from 288.15 to 313.15 K. The results showed that the solubility of 5′-CMPNa{sub 2} increased with the increasing of temperature and the mole fraction of water in different binary mixtures. The (CNIBS)/Redlich–Kister model and the semi-empirical Apelblat model were applied for the prediction of the experimental data. Both models could give satisfactory simulation results. In addition, the thermodynamic properties of the dissolution process such as Gibbs energy, enthalpy, and entropy were calculated using the van’t Hoff equation and the Gibbs equation. The results indicated that the dissolution process was endothermic.

  7. Experimental study and modelling of heat transfer during condensation of pure fluid and binary mixture on a bundle of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Belghazi, M.; Marvillet, C. [Commissariat a l' Energie Atomique, Grenoble (France). Groupement pour la Recherche sur les Echangeurs thermiques; Bontemps, A. [Universite Joseph Fourier, Grenoble (France). LEGI/GRETh

    2003-03-01

    An experimental investigation was conducted to measure the local heat transfer coefficient for each row in a trapezoidal finned horizontal tube bundle during condensation of both pure fluid (HFC 134a) and several compositions of the non-azeotropic binary mixture HFC 23/HFC 134a. The test section is a 13x3 (rows x columns) tube bundle and the heat transfer coefficient is measured using the modified Wilson plot method. The inlet vapour temperature is fixed at 40{sup o}C and the water flow rate in each active row ranges from 170 to 600 l/h. The test series cover five different finned tubes all commercially available, K11 (11 fins/inch), K19 (19 fins/inch), K26 (26 fins/inch), K32 (32 fins/inch), K40 (40 fins/inch) and their performances were compared. The experimental results were checked against available models predicting the heat transfer coefficient during condensation of pure fluids on banks of finned tubes. Modelling of heat exchange during condensation of binary mixtures on bundles of finned tubes based on the curve condensation model is presented. (author)

  8. Studies on an ester-modified cationic amphiphile in aqueous systems: behavior of binary solutions and ternary mixtures with conventional surfactants.

    Science.gov (United States)

    Lundberg, Dan; Unga, Johan; Galloway, Ashley L; Menger, Fredric M

    2007-11-06

    The aqueous behavior of an ester-modified cationic amphiphile with the molecular structure CH3CH2O(C=O)(CH2)6(C=O)O(CH2)8N+(CH3)3Br-, in the following referred to as A, has been investigated. Systems with A as the only solute, as well as different aqueous mixtures with conventional cationic surfactants, primarily dodecyltrimethylammonium bromide (DTAB), were included in the study. Isotropic solution samples were characterized using 1H NMR, 13C NMR, NMR diffusometry, and conductivity measurements, whereas liquid crystalline samples were investigated by optical polarization microscopy and small-angle X-ray diffraction. The results are compared to the behavior of the binary system of DTAB and water. A does not exhibit a typical surfactant behavior. When it is present as the only solute in a binary aqueous system, it forms neither conventional micelles nor liquid crystalline phases. However, there is clear evidence that it assembles with lower cooperativity into loose clusters at concentrations above 25-30 mM. When A is mixed with DTAB in solution, the two amphiphiles form mixed assemblies, the structure of which varies with the total amphiphile concentration. In concentrated mixtures with alkyltrimethylammonium surfactants, A can participate in hexagonal liquid crystalline phases even when it constitutes a significant fraction of the total amphiphile content.

  9. CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures

    Institute of Scientific and Technical Information of China (English)

    Tengteng Fan; Wenlong Xie; Xiaoyan Ji; Chang Liu; Xin Feng; Xiaohua Lu

    2016-01-01

    The high price and toxicity of ionic liquids (ILs) have limited the design and application of supported ionic liquid membranes (SILMs) for CO2 separation in both academic and industrial fields. In this work, [Choline][Pro]/poly-ethylene glycol 200 (PEG200) mixtures were selected to prepare novel SILMs because of their green and cost-effective characterization, and the CO2/N2 separation with the prepared SILMs was investigated experimental y at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was ob-served with high CO2 permeability ranged in 343.3-1798.6 barrer and high CO2/N2 selectivity from 7.9 to 34.8. It was also found that the CO2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to 38 mPa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantial y decreased and the SILMs process was switched from diffusion-control to reaction-control.

  10. 加入惰性固体粒子的二元物系的流动沸腾传热特性%HEAT TRANSFER ON VAPOR-LIQUID-SOLID THREE-PHASE FLOW BOILING OF BINARY MIXTURES

    Institute of Scientific and Technical Information of China (English)

    王春雨; 李修伦

    2000-01-01

    Experimental study on vapor-liquid-solid three-phase flow boiling heat transfer of ethanol-water binary mixtures in a vertical tube was carried out. The results showed that with the presence of inert solid particles in binary mixtures, the heat transfer coefficients were 1.5—2.0 times of those with the vapor-liquid two-phase flow. The effects of several parameters on heat transfer were also discussed. The results showed that the three-phase flow boiling heat transfer coefficients of binary mixtures decreased with the increase of the composition of ethanol in binary mixtures when the composition were within 3%—18% and the heat transfer coefficients increased with the increase of the heat flux and the flow rate. The three-phase flow boiling heat transfer coefficients of binary mixtures increased with the increase of the volume fractions of solid particles and this tendency was the same for different particles. But the enhancement by particles with dissimilar physical properties are not the same.It was due to their different density, specific heat and thermal conductivity. The heat transfer coefficients increased with the increase of these three properties. Surface wettability had great effects on the enhancement of boiling heat transfer. Heat transfer coefficients increased with the decrease of the surface wettability, which was shown by the polyacrylamide particles.

  11. Binary, ternary and quaternary liquid-liquid equilibria in 1-butanol, oleic acid, water and n-heptane mixtures

    NARCIS (Netherlands)

    Winkelman, J. G. M.; Kraai, G. N.; Heeres, H. J.

    2009-01-01

    This work reports on liquid-liquid equilibria in the system 1-butanol, oleic acid, water and n-heptane used for biphasic, lipase catalysed esterifications. The literature was studied on the mutual solubility in binary systems of water and each of the organic components. Experimental results were obt

  12. Lipase-Catalyzed Esterification of Ferulic Acid with Oleyl Alcohol in Ionic Liquid/Isooctane Binary Systems

    DEFF Research Database (Denmark)

    Chen, Bilian; Liu, Huanzhen; Guo, Zheng;

    2011-01-01

    Lipase-catalyzed synthesis of ferulic acid oleyl alcohol ester in an ionic liquid (IL)/isooctane system was investigated. Considerable bioconversion and volumetric productivity were achieved in inexpensive 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6]) and 1-methyl-3-octylimidazolium....... Variations of the ratios of IL/isooctane and concentrations of oleyl alcohol also profoundly affected the volumetric productivity. To a higher extent, [Hmim][PF6]/isooctane and [Omim][PF6]/isooctane show similar reaction behaviors. Under the optimized reaction conditions (60 °C, 150 mg of Novozym 435 and 100...... mg of molecular sieves), up to 48.50 mg/mL productivity of oleyl feruleate could be achieved for the [Hmim][PF6]/isooctane (0.5 mL/1.5 mL) system with a substrate concentration of ferulic acid of 0.08 mmol/mL and oleyl alcohol of 0.32 mmol; while an optimum volumetric productivity of 26.92 mg...

  13. Representation and validation of liquid densities for pure compounds and mixtures

    DEFF Research Database (Denmark)

    Diky, Vladimir; O'Connell, John P.; Abildskov, Jens

    2015-01-01

    values at unmeasured conditions. The model has been shown to successfully represent and validate the pressure and temperature dependence of liquid densities greater than 1.5 of the critical density for pure compounds, binary mixtures, and ternary mixtures from the triple to critical temperatures...... at pressures up to 106 kPa. The systems include the full range of organic compounds, including complex solutions, and ionic liquids. Minimal data are required for making predictions....

  14. Impact of water dilution and cation tail length on ionic liquid characteristics: Interplay between polar and non-polar interactions

    Science.gov (United States)

    Hegde, Govind A.; Bharadwaj, Vivek S.; Kinsinger, Corey L.; Schutt, Timothy C.; Pisierra, Nichole R.; Maupin, C. Mark

    2016-08-01

    The recalcitrance of lignocellulosic biomass poses a major challenge that hinders the economical utilization of biomass for the production of biofuel, plastics, and chemicals. Ionic liquids have become a promising solvent that addresses many issues in both the pretreatment process and the hydrolysis of the glycosidic bond for the deconstruction of cellulosic materials. However, to make the use of ionic liquids economically viable, either the cost of ionic liquids must be reduced, or a less expensive solvent (e.g., water) may be added to reduce the overall amount of ionic liquid used in addition to reducing the viscosity of the binary liquid mixture. In this work, we employ atomistic molecular dynamics simulations to investigate the impact of water dilution on the overall liquid structure and properties of three imidazolium based ionic liquids. It is found that ionic liquid-water mixtures exhibit characteristics that can be grouped into two distinct regions, which are a function of the ionic liquid concentration. The trends observed in each region are found to correlate with the ordering in the local structure of the ionic liquid that arises from the dynamic interactions between the ion pairs. Simulation results suggest that there is a high level of local ordering in the molecular structure at high concentrations of ionic liquids that is driven by the aggregation of the cationic tails and the anion-water interactions. It is found that as the concentration of ionic liquids in the binary mixture is decreased, there is a point at which the competing self and cross interaction energies between the ionic liquid and water shifts away from a cation-anion dominated regime, which results in a significant change in the mixture properties. This break point, which occurs around 75% w/w ionic liquids, corresponds to the point at which water molecules percolate into the ionic liquid network disrupting the ionic liquids' nanostructure. It is observed that as the cationic alkyl

  15. Unusual phase separation and rheological behavior of poly(ethylene oxide)/ionic liquid mixtures with specific interactions.

    Science.gov (United States)

    Xiao, Zhilin; Larson, Ronald G; Chen, Yunlei; Zhou, Chenting; Niu, Yanhua; Li, Guangxian

    2016-09-28

    The phase separation behavior of poly(ethylene oxide) (PEO) in ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) was investigated by rheological, optical microscopy, FT-IR and DSC measurements. It is demonstrated that specific interactions, particularly the hydrogen bonding between PEO and the ionic liquids as evidenced by FT-IR, in which a subtle but apparent absorption peak shift near the phase transition appears, account for the unusual low critical solution temperature (LCST) phase separation. Unlike the typical trend in which the storage modulus G' simply increases with temperature near the phase boundary for polymer blends without specific interaction, in our study, a novel "V-shaped" rheological response is observed, namely a dip in G' followed by an upturn, especially at low PEO concentration (<50 wt%). The magnitude of the "V" dip has heating rate and frequency dependences, while Tr (the phase transition temperature) is almost unchanged with heating rate and frequency. Upon increasing the alkyl chain length on the imidazolium ring from an ethyl to a butyl, the "V-shape" becomes more prominent and shifts to higher temperature, which is consistent with the results of FT-IR and DSC, evidently due to the stronger hydrogen bonding interaction between PEO and [BMIM][BF4] than [EMIM][BF4]. This unusual "V" dip might be tentatively ascribed to the coupling effects of the breaking of the "hydrogen bonding cage" formed between PEO chains and IL molecules and dissolution of the heterogeneous clusters as verified by FT-IR and TEM, respectively, and the following upturn is dominated by the interface formation upon phase separation.

  16. Lipase-catalyzed esterification of ferulic Acid with oleyl alcohol in ionic liquid/isooctane binary systems.

    Science.gov (United States)

    Chen, Bilian; Liu, Huanzhen; Guo, Zheng; Huang, Jian; Wang, Minzi; Xu, Xuebing; Zheng, Lifei

    2011-02-23

    Lipase-catalyzed synthesis of ferulic acid oleyl alcohol ester in an ionic liquid (IL)/isooctane system was investigated. Considerable bioconversion and volumetric productivity were achieved in inexpensive 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF(6)]) and 1-methyl-3-octylimidazolium hexafluorophosphate ([Omim][PF(6)]) mediated systems, and thus, the two types of ILs were selected for further optimization of variables. The results showed that, before reaching a maximum, the increase of ferulic acid concentration, temperature, or enzyme dosage led to an increase in volumetric productivity. Variations of the ratios of IL/isooctane and concentrations of oleyl alcohol also profoundly affected the volumetric productivity. To a higher extent, [Hmim][PF(6)]/isooctane and [Omim][PF(6)]/isooctane show similar reaction behaviors. Under the optimized reaction conditions (60 °C, 150 mg of Novozym 435 and 100 mg of molecular sieves), up to 48.50 mg/mL productivity of oleyl feruleate could be achieved for the [Hmim][PF(6)]/isooctane (0.5 mL/1.5 mL) system with a substrate concentration of ferulic acid of 0.08 mmol/mL and oleyl alcohol of 0.32 mmol; while an optimum volumetric productivity of 26.92 mg/mL was obtained for the [Omim][PF(6)]/ isooctane (0.5 mL/1.5 mL) system under a similar reaction condition other than the substrate concentrations of ferulic acid at 0.05 mmol/mL and oleyl alcohol at 0.20 mmol.

  17. Predicting the excess solubility of acetanilide, acetaminophen, phenacetin, benzocaine, and caffeine in binary water/ethanol mixtures via molecular simulation

    Science.gov (United States)

    Paluch, Andrew S.; Parameswaran, Sreeja; Liu, Shuai; Kolavennu, Anasuya; Mobley, David L.

    2015-01-01

    We present a general framework to predict the excess solubility of small molecular solids (such as pharmaceutical solids) in binary solvents via molecular simulation free energy calculations at infinite dilution with conventional molecular models. The present study used molecular dynamics with the General AMBER Force Field to predict the excess solubility of acetanilide, acetaminophen, phenacetin, benzocaine, and caffeine in binary water/ethanol solvents. The simulations are able to predict the existence of solubility enhancement and the results are in good agreement with available experimental data. The accuracy of the predictions in addition to the generality of the method suggests that molecular simulations may be a valuable design tool for solvent selection in drug development processes.

  18. Application of the ERAS model to volumetric properties of binary mixtures of banana oil with primary and secondary alcohols (C1-C4) at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Behroozi, Mahboobe [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Zarei, Hosseinali, E-mail: zareih@basu.ac.i [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

    2011-05-15

    The densities of binary mixtures of {l_brace}isoamyl acetate + alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol){r_brace}, including those of pure liquids, over the entire composition range were measured at temperatures (293.15 to 333.15) K and atmospheric pressure by means of a vibrating-tube densimeter. The excess molar volume, V{sub m}{sup E}, thermal expansion coefficients, {alpha}, and their excess values, {alpha}{sup E}, were calculated from density data. The V{sub m}{sup E} values are positive over the entire range of composition and temperature and become more positive with increasing temperature for all of the mixtures except for the (isoamyl acetate + methanol) mixture. The V{sub m}{sup E} values were correlated by Redlich-Kister equation and the extended real associated solution (ERAS) model was used for describing V{sub m}{sup E} values at T = 303.15 K.

  19. Self-assembled microstructures from 1,2-ethanediol suspensions of pure and binary mixtures of neutral and acidic biological galactosylceramides.

    Science.gov (United States)

    Archibald, D D; Mann, S

    1994-01-01

    Optical and electron microscopy were employed to characterize microstructures formed by thermal mechanical treatment of glycol suspensions of various pure and binary mixtures of the brain-derived galactosphingolipids hydroxy fatty acid cerebroside (HFA-Cer), non-hydroxy fatty acid cerebroside (NFA-Cer) and sulfatide (S-Cer). Negative staining indicated some new features of the neutral cerebroside suspensions in glycol. HFA-Cer formed a small fraction of both unilamellar cylinders (ULCs) (lumina ca. 27 nm) and giant multilamellar cochleates in addition to the typical nonhelical multilamellar cylinders (MLCs) (lumina ca. 10-30 nm). NFA-Cer formed a gel composed of a significant fraction of very long ULCs (lumina ca. 17 nm) without helical substructure, in addition to multilamellar helical structures such as ribbons and cylinders (lumina ca. 70 nm). Anisotropic lamellar micelle-shards of NFA-Cer were also detected by negative staining. S-Cer formed short ULCs (lumina ca. 44 nm) with no obvious helical substructure. Complex mixture data are thought to result from thermodynamic and kinetic factors. HFA-Cer is highly insoluble and promotes a network of rigid intralamellar hydrogen bonding that tends to exclude other lipids. NFA-Cer stabilizes helical defects in the lamellae, and S-Cer enhances disorder or micellization. The processes of microstructure nucleation and lipid phase separation were affected by mixtures such that metastable microstructures were trapped or the length of lamellar cylinders was altered.

  20. Molecular simulation of fluids with non-identical intermolecular potentials: Thermodynamic properties of 10-5 + 12-6 Mie potential binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Stiegler, Thomas [Technische Fakultät, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5a, 91058 Erlangen (Germany); Sadus, Richard J., E-mail: rsadus@swin.edu.au [Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218 Hawthorn, Victoria 3122 (Australia)

    2015-02-28

    General methods for combining interactions between particles characterised by non-identical intermolecular potentials are investigated. The combination methods are tested by performing molecular dynamics simulations to determine the pressure, energy, isochoric and isobaric heat capacities, thermal expansion coefficient, isothermal compressibility, Joule-Thomson coefficient, and speed of sound of 10-5 + 12-6 Mie potential binary mixtures. In addition to the two non-identical Mie potentials, mixtures are also studied with non-identical intermolecular parameters. The combination methods are compared with results obtained by simply averaging the Mie exponents. When either the energy or size parameters are non-identical, very significant differences emerge in the thermodynamic properties predicted by the alternative combination methods. The isobaric heat capacity is the thermodynamic property that is most affected by the relative magnitude of the intermolecular potential parameters and the method for combining non-identical potentials. Either the arithmetic or geometric combination of potentials provides a simple and effective way of performing simulations involving mixtures of components characterised by non-identical intermolecular potentials, which is independent of their functional form.