Dynamic thermodiffusion model for binary liquid mixtures.
Eslamian, Morteza; Saghir, M Ziad
2009-07-01
Following the nonequilibrium thermodynamics approach, we develop a dynamic model to emulate thermo-diffusion process and propose expressions for estimating the thermal diffusion factor in binary nonassociating liquid mixtures. Here, we correlate the net heat of transport in thermodiffusion with parameters, such as the mixture temperature and pressure, the size and shape of the molecules, and mobility of the components, because the molecules have to become activated before they can move. Based on this interpretation, the net heat of transport of each component can be somehow related to the viscosity and the activation energy of viscous flow of the same component defined in Eyring's reaction-rate theory [S. Glasstone, K. J. Laidler, and H. Eyring, (McGraw-Hill, New York, 1941)]. This modeling approach is different from that of Haase and Kempers, in which thermodiffusion is considered as a function of the thermostatic properties of the mixture such as enthalpy. In simulating thermodiffusion, by correlating the net heat of transport with the activation energy of viscous flow, effects of the above mentioned parameters are accounted for, to some extent of course. The model developed here along with Haase-Kempers and Drickamer-Firoozabadi models linked with the Peng-Robinson equation of sate are evaluated against the experimental data for several recent nonassociating binary mixtures at various temperatures, pressures, and concentrations. Although the model prediction is still not perfect, the model is simple and easy to use, physically justified, and predicts the experimental data very good and much better than the existing models. PMID:19658691
Dynamic thermodiffusion model for binary liquid mixtures
Eslamian, Morteza; Saghir, M. Ziad
2009-07-01
Following the nonequilibrium thermodynamics approach, we develop a dynamic model to emulate thermo-diffusion process and propose expressions for estimating the thermal diffusion factor in binary nonassociating liquid mixtures. Here, we correlate the net heat of transport in thermodiffusion with parameters, such as the mixture temperature and pressure, the size and shape of the molecules, and mobility of the components, because the molecules have to become activated before they can move. Based on this interpretation, the net heat of transport of each component can be somehow related to the viscosity and the activation energy of viscous flow of the same component defined in Eyring’s reaction-rate theory [S. Glasstone, K. J. Laidler, and H. Eyring, The Theory of Rate Processes: The Kinetics of Chemical Reactions, Viscosity, Diffusion and Electrochemical Phenomena (McGraw-Hill, New York, 1941)]. This modeling approach is different from that of Haase and Kempers, in which thermodiffusion is considered as a function of the thermostatic properties of the mixture such as enthalpy. In simulating thermodiffusion, by correlating the net heat of transport with the activation energy of viscous flow, effects of the above mentioned parameters are accounted for, to some extent of course. The model developed here along with Haase-Kempers and Drickamer-Firoozabadi models linked with the Peng-Robinson equation of sate are evaluated against the experimental data for several recent nonassociating binary mixtures at various temperatures, pressures, and concentrations. Although the model prediction is still not perfect, the model is simple and easy to use, physically justified, and predicts the experimental data very good and much better than the existing models.
Nucleation in a Sheared Liquid Binary Mixture.
Min, Kyung-Yang
When a binary liquid mixture of lutidine plus water (LW) is quenched to a temperature T and is exposed to a continuous shear rate S, the result is a steady-state droplet distribution. This steady state can be probed by measuring the unscattered intensity I_{f}, or the scattered intensity I_{s}, as a function of delta T and S. In the experiments described here, S is fixed and delta T is varied in a step-wise fashion. The absence of hysteresis was probed in two separate experiments: First, I_{f} was measured as a function of S for a given delta T. Next, I_{f} was measured as a function of delta T for a given S. In either case, the hysteresis associated with the shear-free nucleation is absent. In addition, a flow-history dependent hysteresis was studied. In the 2-dimensional parameter space consisting of S and delta T, the onset of nucleation uniquely determines a cloud point line. A plot of the cloud point line exhibits two segments of different slopes with a cross-over near the temperature corresponding to the Becker-Doring limit. The classical picture of a free energy barrier was reformulated to explain this cross-over behavior. Next, photon correlation spectroscopy was used to study the dependence of the transient nucleation behavior on the initial states. A unique feature of this study is that this initial state can be conveniently adjusted by varying the shear rate S to which the mixture is initially exposed. The shear is then turned off, and the number density N(t), as well as the mean radius of the growing droplets, is monitored as a function of time. It was possible to measure the droplet density at a very early stage of phase separation where the nucleation rate J was close to zero. The measurement reveals that N(t) depends critically on the initial state of the metastable system. When the shear is large enough to rupture the droplets as small as the critical size, N(t) increases very slowly. Measurements of the nucleation rates vs. the square of the
Solvatochromic Study on Binary Solvent Mixtures with Ionic Liquids
Koel, Mihkel
2008-08-01
Solvent effects on 2,6-dichloro-4-(2,4,6-triphenyl-pyridinium-1-yl)phenolate [ET (33) dye] and 7- diethylamino-3,4-benzophenoxazine-2-one (Nile Red) in binary mixtures of organic solvents (acetone, acetonitrile, propylene carbonate, methanol and ethane-1,2-diol) with 1,3-dialkyl imidazoliumbased ionic liquids were studied by UV-visible spectroscopy. Highly nonlinear behaviour of mixtures of alcohols and ionic liquids was found. A preferential solvation model was applied to the data obtained on solvatochromic shifts over the entire mixing range. It is fitting the data well for alcohol mixtures and for other solvent mixtures with different ionic liquids.
Heat capacity singularity of binary liquid mixtures at the liquid-liquid critical point.
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. PMID:24229116
Computation of the acoustic nonlinearity parameter in organic liquid binary mixtures
Institute of Scientific and Technical Information of China (English)
无
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.
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...
(Vapor + liquid) equilibria of binary mixtures containing light alcohols and ionic liquids
International Nuclear Information System (INIS)
This work presents (vapor + liquid) equilibrium (VLE) of binary mixtures containing methanol or ethanol and three imidazolium based ionic liquids: 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium acetate, and 1-butyl-3-methylimidazolium hydrogen sulfate. VLE measurements were carried out over the whole range of composition between (283.15 and 298.15) K using a static apparatus. Activity coefficients γi of these solvents in the ionic liquids have been determined from the VLE data and correlated using the NRTL model. The results show that the NRTL model can be applied successfully with systems containing ionic liquids.
(Vapor + liquid) equilibria of binary mixtures containing light alcohols and ionic liquids
Energy Technology Data Exchange (ETDEWEB)
Revelli, Anne-Laure [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, 1 rue Grandville, BP 20451, 54001 Nancy (France); Mutelet, Fabrice, E-mail: mutelet@ensic.inpl-nancy.f [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, 1 rue Grandville, BP 20451, 54001 Nancy (France); Jaubert, Jean-Noel [Laboratoire de Thermodynamique des Milieux Polyphases, Nancy-Universite, 1 rue Grandville, BP 20451, 54001 Nancy (France)
2010-02-15
This work presents (vapor + liquid) equilibrium (VLE) of binary mixtures containing methanol or ethanol and three imidazolium based ionic liquids: 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium acetate, and 1-butyl-3-methylimidazolium hydrogen sulfate. VLE measurements were carried out over the whole range of composition between (283.15 and 298.15) K using a static apparatus. Activity coefficients gamma{sub i} of these solvents in the ionic liquids have been determined from the VLE data and correlated using the NRTL model. The results show that the NRTL model can be applied successfully with systems containing ionic liquids.
Liquid-liquid interfacial properties of a symmetrical Lennard-Jones binary mixture
International Nuclear Information System (INIS)
We determine the interfacial properties of a symmetrical binary mixture of equal-sized spherical Lennard-Jones molecules, σ11 = σ22, with the same dispersive energy between like species, ϵ11 = ϵ22, 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 rc 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 rc 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 with a desorption of the molecules
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
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.
Volumetric properties of binary mixtures of benzene with cyano-based ionic liquids
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.
Dynamics of binary phase separation in liquid He-3-He-4 mixtures
Hoffer, J. K.; Sinha, D. N.
1986-01-01
Binary phase-separation dynamics in liquid mixtures of He-3 and He-4 has been investigated near the tricritical point with laser-light scattering techniques. Rapid decompression of the mixtures results in quenches into the miscibility gap so that both the metastable and unstable (spinodal) regions can be probed. Quenches into the unstable region allowed measurements of the normalized dynamic structure factor S(k,t) that confirm the dynamical scaling hypotheses for spinodal decomposition. Measurements made for concentrations well away from the tricritical value show different behavior and suggest the presence of a spinodal boundary. Forward scattering intensities for shallow quenches probe nucleation phenomena and permit quantitative measurements of anomalous super-cooling as a function of quench rate. Comparisons with data in organic binary mixtures are given.
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.
Iwahashi, Makio; Takebayashi, Shintaro; Umehara, Atsushi; Kasahara, Yasutoshi; Minami, Hideyuki; Matsuzawa, Hideyo; Inoue, Tohru; Takahashi, Hiroshi
2004-05-01
Dimer structure and liquid structure of fatty acids in the binary liquid mixture of dodecanoic (LA) and 3-phenylpropionic acids (PPA) were studied through the measurements of DSC, self-diffusion coefficient (D), density, viscosity, 13C NMR spin-lattice relaxation time, small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS). The phase diagram of LA/PPA mixture exhibited a typical eutectic pattern, which means that LA and PPA are completely immiscible in solid phase. In the liquid phase of the LA/PPA mixture, D of LA always differed from that of PPA irrespective of their compositions. This exhibited that, in the liquid phase of the binary mixture of fatty acids giving a complete eutectic in the solid phase, the fatty acid dimers are composed of the same fatty acid species irrespective of their compositions. The liquid structure of the LA/PPA mixture was clarified through the SAXS and also the SANS measurements. PMID:15081860
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.
International Nuclear Information System (INIS)
Highlights: → Thermodynamic study of diethylenetriamine + 2-methyl-1-propanol, +2-propanol or +1-butanol have been made. → Excess molar volumes and isentropic compressibility were determined. → Types of interactions were discussed based on derived properties. - Abstract: Densities, ρ, viscosities, η, 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, VmE and deviations in isentropic compressibility, Δκs, and speed of sound, Δu have been evaluated. Viscosity data were used to compute deviations in viscosity and excess Gibbs energy of activation of viscous flow ΔG*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.
Guevara-Carrion, Gabriela; Janzen, Tatjana; Muñoz-Muñoz, Y. Mauricio; Vrabec, Jadran
2016-03-01
Mutual diffusion coefficients of all 20 binary liquid mixtures that can be formed out of methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride without a miscibility gap are studied at ambient conditions of temperature and pressure in the entire composition range. The considered mixtures show a varying mixing behavior from almost ideal to strongly non-ideal. Predictive molecular dynamics simulations employing the Green-Kubo formalism are carried out. Radial distribution functions are analyzed to gain an understanding of the liquid structure influencing the diffusion processes. It is shown that cluster formation in mixtures containing one alcoholic component has a significant impact on the diffusion process. The estimation of the thermodynamic factor from experimental vapor-liquid equilibrium data is investigated, considering three excess Gibbs energy models, i.e., Wilson, NRTL, and UNIQUAC. It is found that the Wilson model yields the thermodynamic factor that best suits the simulation results for the prediction of the Fick diffusion coefficient. Four semi-empirical methods for the prediction of the self-diffusion coefficients and nine predictive equations for the Fick diffusion coefficient are assessed and it is found that methods based on local composition models are more reliable. Finally, the shear viscosity and thermal conductivity are predicted and in most cases favorably compared with experimental literature values.
International Nuclear Information System (INIS)
Highlights: → Macroscopic and molecular level interactions of imidazolium ionic liquids in ethylene glycol have been determined. → VmE is positive over the whole composition range for all the investigated mixtures. → Multiple hydrogen bonding interactions are prevailing between unlike components in mixtures of varying strengths. → Microscopic level interactions are not reflected in the mixing macroscopic behaviour. - Abstract: The thermodynamic behaviour of imidazolium based ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride [C4mim][Cl]; 1-octyl-3-methylimidazolium chloride [C8mim][Cl], and 1-butyl-3-methylimidazolium methylsulfate [C4mim][C1OSO3] in ethylene glycol [HOCH2CH2OH] (EG) have been investigated over the whole composition range at T = (298.15 to 318.15) K to probe the interactions in bulk. For the purpose, volumetric properties such as excess molar volume, VmE, apparent molar volume, Vφ,i, and its limiting values at infinite dilution, Vφ,i∞, have been calculated from the experimental density measurements. The molecular scale interactions between ionic liquids and EG have been investigated through Fourier transform infrared (FTIR) and 1H NMR spectroscopy. The shift in the vibrational frequency for C-H stretch of aromatic ring protons of ILs and O-H stretch of EG molecules has been analysed. The NMR chemical shifts for various protons of RTILS or EG molecules and their deviations show multiple hydrogen bonding interactions of varying strengths between RTILs and EG in their binary mixtures.
Liquid-crystal phase diagrams of binary mixtures of hard spherocylinders.
Cinacchi, Giorgio; Mederos, Luis; Velasco, Enrique
2004-08-22
We have built the liquid crystal phase diagram of several binary mixtures of freely rotating hard spherocylinders employing a second-order virial density functional theory with Parsons scaling, suitably generalized to deal with mixtures and smectic phases. The components have the same diameter and aspect ratio of moderate value, typical of many mesogens. Attention has been paid to smectic-smectic demixing and the types of arrangement that rods can adopt in layered phases. Results are shown to depend on the aspect ratio of the individual components and on the ratio of their lengths. Smectic phases are seen not to easily mix together at sufficiently high pressures. Layered phases where the longer rods are the majority component have a smectic-A structure. In the opposite case, a smectic-A(2) phase is obtained where the shorter particles populate the layers and the longer ones prefer to stay parallel to the latter in the interlayer region. PMID:15303954
Guevara-Carrion, Gabriela; Vrabec, Jadran; Hasse, Hans
2012-03-01
Transport properties of ammonia and of the binary mixture ammonia + methanol are predicted for a broad range of liquid states by molecular dynamics (MD) simulation on the basis of rigid, non-polarizable molecular models of the united-atom type. These models were parameterized in preceding work using only experimental vapor-liquid equilibrium data. The self- and the Maxwell-Stefan (MS) diffusion coefficients as well as the shear viscosity are obtained by equilibrium MD and the Green-Kubo formalism. Non-equilibrium MD is used for the thermal conductivity. The transport properties of liquid ammonia are predicted for temperatures between 223 K and 473 K up to pressures of 200 MPa and are compared to experimental data and correlations thereof. Generally, good agreement is achieved. The predicted self-diffusion coefficient as well as the shear viscosity deviates on average by less than 15 % from the experiment and the thermal conductivity by less than 6 %. Furthermore, the self- and the MS transport diffusion coefficients as well as the shear viscosity of the liquid mixture ammonia + methanol are studied at different compositions and compared to the available experimental data.
Density functional theory of gas-liquid phase separation in dilute binary mixtures.
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. PMID:27115676
Solid-Liquid Equilibria for the Binary Mixtures 1,4-Xylene + Ethylbenzene and 1,4-Xylene + Toluene
DEFF Research Database (Denmark)
Huyghe, Raphaël; Rasmussen, Peter; Thomsen, Kaj
2004-01-01
Solid-liquid equilibrium (SLE) data for the binary mixtures 1,4-xylene + ethylbenzene, and 1,4-xylene + toluene have been measured using differential scanning calorimetry (DSC) in the temperature range from 133.15 K to 293.15 K.......Solid-liquid equilibrium (SLE) data for the binary mixtures 1,4-xylene + ethylbenzene, and 1,4-xylene + toluene have been measured using differential scanning calorimetry (DSC) in the temperature range from 133.15 K to 293.15 K....
van der Werff, Louise C; Robinson, Andrea J; Kyratzis, Ilias L
2012-11-12
A combinatorial approach was developed for the rapid determination of thermochromic behavior of a large number of binary and ternary sterol based thermochromic liquid crystalline formulations. A binary mixture containing cholesteryl oleyl carbonate and cholesteryl nonanoate, and ternary mixtures also containing a third component, either cholesteryl oleate, cholesteryl benzoate, cholesteryl 2,4-dichlorobenzoate or cholesteryl propionate, were formulated via solvent deposition into a black Teflon coated aluminum 96 well plate. The temperature of the well plate was then varied, and the color appearance of the deposited mixture in each well was recorded. This approach allowed expedient examination of the thermochromic behavior for a large range of liquid crystal formulations. The accuracy of the rapid combinatorial technique was validated on selected thermochromic liquid crystal mixture compositions by comparing well thermochromic output with that observed using UV-vis spectroscopy on material produced in gram quantities. PMID:23072483
Domańska, U; Królikowska, M
2012-09-01
Densities and viscosities have been determined for binary mixtures of the ionic liquids (ILs) 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN], or 1-butyl-4-methylpyridinium thiocyanate [BMPy][SCN], or 1-butyl-1-methylpyrrolidinium thiocyanate [BMPYR][SCN], or 1-butyl-1-methylpiperidinium thiocyanate [BMPIP][SCN] with water over wide range of temperatures (298.15-348.15) K and ambient pressure. The thermal properties of [BMPy][SCN], i.e. glass transition temperature and the heat capacity at glass transition, have been measured using a differential scanning microcalorimetry, DSC. The decomposition of [BMPy][SCN] was detected. The density and viscosity correlations for these systems have been made using an empirical second-order polynomial and by the Vogel-Fulcher-Tammann equation, respectively. The concentration dependences have been described by polynomials. The excess molar volumes and deviations in viscosity have been calculated from the experimental values and were correlated by Redlich-Kister polynomial expansions. The variations of these parameters, with compositions of the mixtures and temperature, have been discussed in terms of molecular interactions. A qualitative analysis of the trend of properties with composition and temperature was performed. Further, the excess partial molar volumes, [Formula: see text] and [Formula: see text], were calculated and discussed. The isobaric expansivities (coefficient of thermal expansion), α, and the excess isobaric expansivities, α(E), were determined for four ILs and their mixtures with water. The results indicate that the interactions of thiocyanate ILs with water is not as strong as with alcohols, which is shown by the positive/slightly negative excess molar volumes in these binary systems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10953-012-9875-7) contains supplementary material, which is available to authorized users. PMID:23002317
International Nuclear Information System (INIS)
A static VLE apparatus has been used for the measurement of the (vapour + liquid + liquid) equilibrium of the (propylene + isopropanol + water) system at T = 313.15 K and pressures between (1.381 and 1.690) MPa. Using an isothermal flow calorimeter, HE values have been obtained for the binary system (isopropanol + water) over the temperature range from (313.15 to 353.15) K and pressures from (3.8 to 4.19) MPa. For the pseudo-binary mixture (propylene + (isopropanol + water)), HE values have been measured in the temperature range from (313.15 to 353.15) K and pressures from (1.997 to 5.89) MPa. This last mixture was studied starting from (isopropanol + water) at 0.25, 0.50, and 0.75 molar compositions in isopropanol. The new data, together with the available phase equilibrium and HE data from the literature, have been regressed by a conventional GE-EoS model reaching satisfactory results, except for the VLLE representation
Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S
2013-01-01
Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami
Pires, J; Timperman, L.; Jacquemin, J.; A. Balducci; Anouti, M.
2013-01-01
Density, ?, viscosity, ?, and conductivity, s, measurements of binary mixtures containing the pyrrolidinium nitrate Protic Ionic Liquid (PIL) and propylene carbonate (PC), are determined at the atmospheric pressure as a function of the temperature from (283.15 to 353.15) K and within the whole composition range. The temperature dependence of both the viscosity and conductivity of each mixture exhibits a non-Arrhenius behaviour, but is correctly fitted by using the Vogel–Tamman–Fulcher (VTF) e...
Density functional theory of gas–liquid phase separation in dilute binary mixtures
Okamoto, Ryuichi; Onuki, Akira
2016-06-01
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 Δ {μ\\text{s}} (the Gibbs energy of transfer) is considerably larger than the thermal energy {{k}\\text{B}}T 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 {{k}\\text{B}}Tn2\\ell\\exp ≤ft(Δ {μ\\text{s}}/{{k}\\text{B}}T\\right) , where n2\\ell is the solute density added in liquid. For \\exp ≤ft(Δ {μ\\text{s}}/{{k}\\text{B}}T\\right)\\gg 1 , 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.
International Nuclear Information System (INIS)
Highlights: • Calculations of excess quantities of binary mixtures of IL + molecular solvent. • Analysis of excess properties for mixtures in order to find some regularities. • Balankina’s functions as tool to systematize excesses of IL + solvent mixtures. • Discussion of calculated absolute and relative excesses. • Prediction of absolute and relative excesses for similar binary systems. - Abstract: The excess speed of sound, excess molar volume and excess molar isentropic compressibility of 52 binary mixtures containing Ionic Liquids at T = 298.15 K were calculated using selected literature speed of sound and density data. The second components were alcohols: methanol, or ethanol, or 1-propanol, or 2-propanol, or 1-butanol or other solvents: acetone, acetonitrile, tetrahydrofuran, dichloromethane and dimethylsulfoxide. The Balankina’s relative excesses, Xbal, i.e. the ratios between excess and ideal quantities XE/Xid were also determined to reduce the structural impact of pure components to absolute excesses. Analysis of quantities determined shows some patterns for concentration dependences of large groups of mixtures; thus, the scheme for influence of anion or cation of Ionic Liquids and solvent on Balankina’s relative excesses was proposed. It seems that presented analysis provide the knowledge about absolute and relative excess quantities for other mixtures without doing the experimental work. It is also visible that analysis of excess molar quantities and Xbal parameters can support the interpretation of interactions which occur between Ionic Liquids and solvent
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.
Kasahara, Yasutoshi; Suzuki, Yuji; Kabasawa, Aino; Minami, Hideyuki; Matsuzawa, Hideyo; Iwahashi, Makio
2010-01-01
Molecular interactions between benzene and hydrocarbons having six carbon atoms, such as hexane, cyclohexane and 1-hexene in their binary liquid mixtures were studied through the measurements of density, viscosity, self-diffusion coefficient, (13)C NMR spin-lattice relaxation time and (1)H NMR chemical shift. CH/pi attraction between hexane and benzene in their binary mixture was observed in a relatively benzene rich region, whereas a special attractive interaction was not observed between cyclohexane and benzene. On the other hand, 1-hexene and benzene in their binary mixtures were characteristic in their self-diffusion coefficient behaviors: 1-hexene more strongly attract benzene not only by the CH/pi attraction but also probably by the p/p interaction between the double bond in 1-hexene and the p-electron in benzene ring. PMID:20032596
Dielectric relaxation in ionic liquid/dipolar solvent binary mixtures: A semi-molecular theory
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
International Nuclear Information System (INIS)
Highlights: ► We measured densities for {alkanol (ethanol or 1-propanol) + boldine} mixtures. ► Liquid densities are reported in the ranges of (1 to 20) MPa and (313 to 363) K. ► Thermodynamic derived properties were calculated using an empirical correlation. ► Extrapolated densities at atmospheric pressure agree with the literature data. - Abstract: In this work, densities of two binary systems of {alkanol (ethanol and 1-propanol) + boldine} are measured at temperatures from (313 to 363) K and pressures up to 20 MPa using an Anton Paar vibrating tube densimeter. Each (alkanol + boldine) system was prepared at five diluted compositions with respect to the alkaloid. These are (x2 = 0.0012, 0.0074, 0.0136, 0.0196, 0.0267) and (x2 = 0.0018, 0.0046, 0.0077, 0.0112, 0.0142) mixed in ethanol and 1-propanol, respectively. Experimental densities are correlated using an empirical 6-parameter equation with deviations within 0.04%. Extrapolated densities at atmospheric pressure agree with the literature data. Isobaric expansivity, isothermal compressibility, thermal pressure coefficient, and internal pressure have been calculated.
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.
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.
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.
Excess heat capacities of (binary + ternary) mixtures containing [emim][BF4] and organic liquids
International Nuclear Information System (INIS)
Highlights: • The CPE and (CPE)ijk data have been measured over entire composition range at four temperatures. • The observed data have been fitted to Redlich–Kister equation. • The observed data have been analyzed in terms of Graph theory. • The values determined by Graph theory compare well with experimental values. - Abstract: The excess heat capacities, CPE and (CPE)ijk (calculated from the measured molar heat capacities, Cp data) of binary 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + pyrrolidin-2-one or 1-methylpyrrolidin-2-one or pyridine (j); pyrrolidin-2-one (i) + pyridine (j) and ternary 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + pyrrolidin-2-one or 1-methylpyrrolidin-2-one (j) + pyridine (k) mixtures have been measured as a function of composition at T = (293.15, 298.15, 303.15 and 308.15) K and 0.1 MPa using micro differential scanning calorimeter. The (CPE)ijk values for the present ternary mixtures are positive over entire range of composition. The CPE and (CPE)ijk data have been fitted to Redlich–Kister equation to compute binary and ternary adjustable parameters along with their standard deviations. The topology of the constituent molecules (Graph theory) has been utilized to obtain the expressions that describe well the CPE and (CPE)ijk data of the present mixtures. It has been observed that Graph theory describes well the CPE and (CPE)ijk data of the binary as well as ternary mixtures
International Nuclear Information System (INIS)
Highlights: ► Osmotic and physical properties of binary mixtures {alcohol + [BMim][TfO]} were measured. ► From experimental data, apparent molar properties and osmotic coefficients were calculated. ► The apparent properties were fitted using a Redlich–Meyer type equation. ► The osmotic coefficients were correlated using the Extended Pitzer model. -- Abstract: In this work, physical properties (densities and speeds of sound) for the binary systems {1-propanol, or 2-propanol, or 1-butanol, or 2-butanol, or 1-pentanol + 1-butyl-3-methylimidazolium trifluoromethanesulfonate} were experimentally measured from T = (293.15 to 323.15) K and at atmospheric pressure. These data were used to calculate the apparent molar volume and apparent molar isentropic compression which were fitted to a Redlich–Meyer type equation. This fit was used to obtain the corresponding apparent molar properties at infinite dilution. On the other hand, the osmotic and activity coefficients and vapor pressures of these binary mixtures were also determined at T = 323.15 K using the vapor pressure osmometry technique. The Extended Pitzer model of Archer was employed to correlate the experimental osmotic coefficients. From the parameters obtained in the correlation, the mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures were calculated
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
International Nuclear Information System (INIS)
Highlights: • Formation of hemiacetal/poly(oxymethylene) hemiacetals in liquid binary mixtures. • Acetaldehyde and a low molecular alcohol (methanol or ethanol or 1-propanol). • Quantitative 13C NMR spectroscopy at temperatures between (255 and 295) K. • Hemiacetals are the predominant species. • (Acetaldehyde + methanol (50 + 50)) at 255 K: hemiacetal (polymers) >80% (≈10%). -- Abstract: Aldehydes react with alcohols to hemiacetals and poly(oxymethylene) hemiacetals. The chemical reaction equilibria of such reactions, in particular in the liquid state, can have an essential influence on the thermodynamic properties and related phenomena like, for example, on the vapour + liquid phase equilibrium. Therefore, thermodynamic models that aim to describe quantitatively such phase equilibria have to consider the chemical reaction equilibrium in the coexisting phases. This is well known in the literature for systems such as, for example, formaldehyde and methanol. However, experimental information on the chemical reaction equilibria in mixtures with other aldehydes (than formaldehyde) and alcohols is extremely scarce. Therefore, quantitative NMR spectroscopy was used to investigate the chemical reaction equilibria in binary mixtures of acetaldehyde and a single alcohol (here either methanol, ethanol or 1-propanol) at temperatures between (255 and 295) K. The results reveal that the majority of the constituents of the mixture is present as hemiacetal and the first two poly(oxymethylene) hemiacetals: in an equimolar mixture of (acetaldehyde + methanol or ethanol or 1-propanol), between about 90% at T = 255 K and about 75% at 295 K. The mole-fraction based chemical reaction equilibrium constants for the formation of those species were determined and some derived properties are reported
International Nuclear Information System (INIS)
Highlights: ► Osmotic coefficients of alcohols with CnMpyNTf2 (n = 2, 3, 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. ► The results have been interpreted in terms of interactions. - Abstract: In this paper, the osmotic and activity coefficients and vapor pressures of the binary mixtures containing the ionic liquids 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, C2MpyNTf2, and 1-methyl-3-propylpyridinium bis(trifluoromethylsulfonyl)imide, C3MpyNTf2, with 1-propanol, or 2-propanol and the ionic liquid 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, C4MpyNTf2, with 1-propanol or 2-propanol or 1-butanol or 2-butanol were determined at T = 323.15 K using the vapor pressure osmometry technique. The influence of the structure of the alcohol and of the ionic liquid on both coefficients and vapor pressures is discussed and a comparison with literature data on binary mixtures containing ionic liquids with different cations and anion is also performed. Besides, the results have been interpreted in terms of solute–solvent and ion–ion interactions. The experimental osmotic coefficients were correlated using the Extended Pitzer model of Archer and the Modified Non-Random Two Liquids model obtaining standard deviations lower than 0.059 and 0.102 respectively, and the mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures were calculated.
K. Narendra; Narayanamurthy, P.; CH. Srinivasu
2010-01-01
The ultrasonic velocity, density and viscosity in binary liquid mixture cyclohexane with o-xylene have been determined at different temperatures from 303.15 to 318.15 K over the whole composition range. The data have been utilized to estimate the excess adiabatic compressibility (βE), excess volumes (VE), excess intermolecular free length (LfE), excess internal pressure (πE) and excess enthalpy (HE) at the above temperatures. The excess values have been found to be useful in estimating the st...
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.
International Nuclear Information System (INIS)
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 {methanol + propan-1-ol + dimethyl carbonate (DMC)}, and four binary mixtures, namely an {alcohol (C3 or C4) + DMC}, 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.
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.
Excess molar volumes of binary mixtures (an ionic liquid + water): A review
International Nuclear Information System (INIS)
Highlights: • Review of excess molar volumes for mixtures of (ionic liquids (ILs) + H2O). • 6 cation groups reviewed including imidazolium and pyrrolidinium groups. • 13 anions reviewed including tetraborate, triflate, and hydrogensulphate. • Effects of anion, cation, and temperature investigated. - Abstract: This review covers recent developments in the area of excess molar volumes for mixtures of {ILs (1) + H2O (2)} where ILs refers to ionic liquids involving cations: imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium and ammonium groups; and anions: tetraborate, triflate, hydrogensulphate, methylsulphate, ethylsulphate, thiocyanate, dicyanamide, octanate, acetate, nitrate, chloride, bromide, and iodine. The excess molar volumes of aqueous ILs were found to cover a wide range of values for the different ILs (ranging from −1.7 cm3 · mol−1 to 1.2 cm3 · mol−1). The excess molar volumes increased with increasing temperature for all systems studied in this review. The magnitude and in some cases the sign of the excess molar volumes for all the aqueous ILs mixtures, apart from the ammonium ILs, were very dependent on temperature. This was particularly important in the dilute IL concentration region. It was found that the sign and magnitude of the excess molar volumes of aqueous ILs (for ILs with hydrophobic cations), was more dependent on the nature of the anion than on the cation
International Nuclear Information System (INIS)
Highlights: • Osmotic coefficients of alcohols with pyrrolidinium ILs 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. • The results have been interpreted in terms of interactions. -- Abstract: The osmotic and activity coefficients and vapour pressures of mixtures containing primary (1-propanol, 1-butanol and 1-pentanol) and secondary (2-propanol and 2-butanol) alcohols with pyrrolidinium-based ionic liquids (1-butyl-1-methyl pyrrolidinium bis(trifluoromethylsulfonyl)imide, C4MpyrNTf2, and 1-butyl-1-methyl pyrrolidinium trifluoromethanesulfonate, C4MpyrTFO) have been experimentally determined at T = 323.15 K. For the experimental measurements, the vapour pressure osmometry technique has been used. The results on the influence of the structure of the alcohol and of the anion of the ionic liquid on the determined properties have been discussed and compared with literature data. For the correlation of the osmotic coefficients obtained, the Extended Pitzer model of Archer and the Modified Non-Random Two Liquids model were applied. The mean molal activity coefficients and the excess Gibbs energy for the studied mixtures were calculated from the parameters obtained in the correlation
Iwahashi, Makio; Takebayashi, Shintaro; Taguchi, Masakazu; Kasahara, Yasutoshi; Minami, Hideyuki; Matsuzawa, Hideyo
2005-02-01
Dimer structure and liquid structure of fatty acids in their binary mixtures such as decanoic acid (DA)/octadecanoic acid (SA) and DA/dodecanoic acid (LA) were studied through the measurements of self-diffusion coefficient (D), differential scanning calorimetry (DSC), density and viscosity. The obtained phase diagrams showed that DA and SA form a eutectic in the solid state but partly a solid solution in the SA-rich region; DA and LA form an incongruent-melting compound which forms a eutectic with DA. In the liquid mixture of DA and SA, the D of DA is larger than that of SA over the entire range of compositions and tends to approach the D of SA with increasing SA-mole fraction; the D of DA in the DA/LA system is also larger than that of LA especially in the LA-poor region and steeply approaches that of LA with increasing LA-mole fraction. These D values and phase diagrams were compared with those for the binary mixtures of n-alkanes (C14/C20, C19/C20 and C20/C24); it is concluded that the two kinds of fatty acids always form their individual homodimers in their liquid mixtures regardless of their compositions and temperatures. PMID:15642581
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.
Chen, Mo; Pendrill, Robert; Widmalm, Göran; Brady, John W; Wohlert, Jakob
2014-10-14
Room temperature ionic liquids (ILs) of the imidazolium family have attracted much attention during the past decade for their capability to dissolve biomass. Besides experimental work, numerous compuational studies have been concerned with the physical properties of both neat ILs and their interactions with different solutes, in particular, carbohydrates. Many classical force fields designed specifically for ILs have been found to yield viscosities that are too high for the liquid state, which has been attributed to the fact that the effective charge densities are too high due to the lack of electronic polarizability. One solution to this problem has been uniform scaling of the partial charges by a scale factor in the range 0.6-0.9, depending on model. This procedure has been shown to improve the viscosity of the models, and also to positively affect other properties, such as diffusion constants and ionic conductivity. However, less attention has been paid to how this affects the overall thermodynamics of the system, and the problems it might create when the IL models are combined with other force fields (e.g., for solutes). In the present work, we employ three widely used IL force fields to simulate 1-n-butyl-3-methyl-imidazolium chloride in both the crystal and the liquid state, as well as its binary mixture with ethanol. Two approaches are used: one in which the ionic charge is retained at its full integer value and one in which the partial charges are uniformly reduced to 85%. We investigate and calculate crystal and liquid structures, molar heat capacities, heats of fusion, self-diffusion constants, ionic conductivity, and viscosity for the neat IL, and ethanol activity as a function of ethanol concentration for the binary mixture. We show that properties of the crystal are less affected by charge scaling compared to the liquid. In the liquid state, transport properties of the neat IL are generally improved by scaling, whereas values for the heat of fusion are
Haugen, Kjetil B; Firoozabadi, Abbas
2006-02-01
This paper investigates the unsteady-state species segregation of binary liquid mixtures in rectangular thermogravitational columns. The analysis leads to a procedure to obtain both molecular and thermal diffusion coefficients from transient separation measurements. Two models are presented: first, an ideal model where buoyancy only depends on temperature and second, a general model where buoyancy also varies with composition. Steady-state measurements are not required regardless of which model is chosen. As a result, the new procedure is faster than steady-state procedures. When either the molecular or thermal diffusion coefficient is known a priori, the other can be obtained without knowledge of fluid properties such as density, viscosity, thermal expansion, and compositional coefficients. PMID:16468889
DEFF Research Database (Denmark)
Cismondi, Martin; Michelsen, Michael Locht
2007-01-01
A general strategy for global phase equilibrium calculations (GPEC) in binary mixtures is presented in this work along with specific methods for calculation of the different parts involved. A Newton procedure using composition, temperature and Volume as independent variables is used for calculation...... 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...
International Nuclear Information System (INIS)
In this study the wetting transition at the liquid-vapour interface of binary organic liquid mixtures has been investigated by x-ray reflectivity. Mixtures of various isomeric alcohols with perfluoromethylcyclohexane (PFMC) served as model systems, with alcohol carbon numbers ranging from 1 to 4. Remarkably different pretransitional behaviour of the thin films below the wetting temperature was observed, which could be classified according to the carbon number. At two-phase coexistence, no pretransitional thin films could be detected for methanol and ethanol, whereas thin-to-thick-film transitions were found for propanol and butanol and their isomers. For 1-propanol and 2-propanol, the surface of the upper, alcohol-rich phase of the gravity-separated mixture displays a wetting transition at Tw = 31.5 deg. C and 38.3 deg. C, respectively, where the thickness of a PFMC-rich film jumps from less than 25 A to values exceeding the experimental resolution of about 1200 A. For 1-butanol, 2-butanol and i-butanol, we found pretransitional film thicknesses increasing up to 100 A, with wetting transitions at Tw = 45.0 deg. C, 34.2 deg. C and 40.1 deg. C, respectively. In the single-phase region, the study of adsorption isotherms above Tw revealed novel behaviour of the adsorbed PFMC-rich film. We observed both a growing film thickness and a significantly changing composition as the coexistence line was approached. Nevertheless, the variation of the excess adsorption with distance from coexistence could still be described by a power law. (author)
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Highlights: • Density and surface tension of [bmim][L-lactate] and its mixtures with alcohol/water were measured. • Physicochemical properties of pure ionic liquid and its mixtures were discussed. • The excess properties of [bmim][L-lactate] + alcohol show some differences with those of [bmim][L-lactate] + water. -- Abstract: The density and surface tension of the pure ionic liquid 1-butyl-3-methyl-imidazolium L-lactate were measured from T (293.15 to 343.15) K. The coefficient of thermal expansion, molecular volume, standard entropy, lattice energy, surface entropy, surface enthalpy, and enthalpy of vaporization were calculated from the experimental values. Density and surface tension were also determined for binary mixtures of {1-butyl-3-methyl-imidazolium L-lactate + water/alcohol (methanol, ethanol, and 1-butanol)} systems over the whole composition range from T (298.15 to 318.15) K at atmospheric pressure. The partial molar volume, excess partial molar volume and apparent molar volume of the component IL and alcohol/water in the binary mixtures were discussed as well as limiting properties at infinite dilution and the thermal expansion coefficients of the four binary mixtures. The surface properties of the four binary mixtures were also discussed
International Nuclear Information System (INIS)
Bubble point temperatures at 95.5 kPa, over the entire composition range, are measured for the binary mixtures formed by m-cresol with: methanol, ethanol, 1-propanol, 2-propanol, and n-, iso-, sec-, and tert-butanols - using a Swietoslawski-type ebulliometer. The liquid phase composition - bubble point temperature measurements are well represented by the Wilson model. (Vapor + liquid) equilibria predicted from the model are presented
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Room temperature ionic liquids (RTILs) are entirely composed of special organic cations and anions, which are liquid near room temperature. Owing to their desirable properties including nonvolatility, high polarity, high selectivity and ease of recycling, RTILs are regarded as suitable solvents for green chemistry,which have been used as reaction media for a number of organic synthesis reactions, catalysis, separation processes and polymerization. As a prototype of RTIL, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] has been used as medium in which some representative photochemical reactions have been previously studied in comparison with volatile organic compounds. It was found that molecular diffusion of solute was significantly retarded and lifetime of transient species was longer in the neat [bmim][PF6]. Laser flash photolysis experiments were carried out using a Nd:YAG laser that provides 266 and 355 nm laser pulse with a duration of 5 ns and a maximum energy of 80 mJ per pulse. Using duroquinone (DQ) as a probe molecule photochemical properties of the ionic liquid [bmim][PF6] and its binary mixed solutions with acetonitrile (MeCN) were investigated at an excitation wavelength of 355 nm by laser flash photolysis technique. Along with the increasing of the fraction of [bmim][PF6] in the mixture, the characteristic absorption peak of triplet excited state 3DQ* showed a blue shift of ca. 20 nm. It was found that the decay of 3DQ* under N2 atmosphere followed a mono-exponential kinetics. Its rate constant increased with xRTIL (VRTIL/VMeCN) before the critical point at xRTIL = 0.3; however, it decreased obviously with xRTIL after the critical point. The experimental results indicate that RTIL didn't react with 3DQ*, which is different from our previous study on anthraquinone in binary solutions of [bmim][PF6] and acetonitrile. In view of the experimental data, it can be concluded that the viscosity and phase transformation are dominant for the effects
Phase Behaviour, Interactions, and Structural Studies of (Amines+Ionic Liquids) Binary Mixtures
Czech Academy of Sciences Publication Activity Database
Jacquemin, J.; Bendová, Magdalena; Sedláková, Zuzana; Holbrey, J.D.; Mullan, C.L.; Youngs, T.G.A.; Pison, L.; Wagner, Zdeněk; Aim, Karel; Costa Gomes, M.F.; Hardacre, Ch.
2012-01-01
Roč. 13, č. 7 (2012), s. 1825-1835. ISSN 1439-4235 R&D Projects: GA ČR GP203/09/P141; GA ČR GA104/07/0444; GA AV ČR IAA400720710; GA ČR GP104/06/P066 Grant ostatní: QUILL(GB) EP/D029538 Institutional research plan: CEZ:AV0Z40720504 Keywords : amines * interactions * ionic liquids Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.349, year: 2012
International Nuclear Information System (INIS)
Highlights: • Novel data for the surface tensions of mixtures [C4mim][NTf2] + [C4C1mim]/[C3mpy]/[C3mpyr]/[C3mpip][NTf2] are presented. • γ were determined at a fixed temperature, 298.2 K, and at atmospheric pressure, for the whole composition range. • Surface tension deviations showed the near ideal behavior of the selected mixtures. • Gibbs adsorption isotherms showed the surface preferential adsorption of one ionic liquid over the other. -- Abstract: While values for thermophysical properties of ionic liquids are becoming widely available, data for ionic liquid mixtures are still scarce. In an effort to overcome this limitation and understand the behavior of ionic liquid mixtures, novel data for the surface tension of mixtures composed of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C4mim][NTf2], with other ionic liquids with a common anion, namely 1-butyl-2,3-dimethylimidazolium, [C4C1mim]+, 3-methyl-1-propylpyridinium, [C3mpy]+, 1-methyl-1-propylpyrrolidinium, [C3mpyr]+, and 1-methyl-1-propylpiperidinium, [C3mpip]+, were measured at T = 298.2 K and atmospheric pressure over the entire composition range. From the surface tension deviations derived from the experimental results, it was possible to infer that the cation alkyl chain length of the second ionic liquid constituting the mixture has a stronger influence in the ideal mixture behavior than the type of family the ionic liquid cation belongs to. The Gibbs adsorption isotherms, estimated from the experimental values, show that the composition of the vapor–liquid interface is not the same as that of the bulk and that the interface is richer in the ionic liquid with the lowest surface tension, [C4mim][NTf2
International Nuclear Information System (INIS)
The values of density (ρ), viscosity (η) and speed of sound (u) have been measured for binary liquid mixtures of γ-butyrolactone (GBL), δ-valerolactone (DVL), and ε-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 (VE), deviation in viscosity (Δη), and deviation in isentropic compressibility (Δκs), are calculated. The results are fitted to a Redlich-Kister type polynomial equation to derive binary coefficients and standard deviations
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.
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.
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.
Liquid mixture viscosities correlation with rational models
Directory of Open Access Journals (Sweden)
Knežević-Stevanović Anđela B.
2014-01-01
Full Text Available In this paper twenty two selected rational correlation models for liquid mixture viscosities of organic compounds were tested on 219 binary sets of experimental data taken from literature. The binary sets contained 3675 experimental data points for 70 different compounds. The Dimitrov-Kamenski X, Dimitrov-Kamenski XII, and Dimitrov-Kamenski XIII models demonstrated the best correlative characteristics for binary mixtures with overall absolute average deviation less then 2%. [Projekat Ministarstva nauke Republike Srbije, br. 172063
Institute of Scientific and Technical Information of China (English)
GuoqingWang; YingkeTan; 等
1996-01-01
A mechanism is proposed for nucleate pool boiling heat transfer along with a general model for both pure liquids and binary mixtrues.A combined physical model of bubble growth is also proposed along with a corresponding bubble growth model for pure liquids on smooth tubes.Using the general model and the bubble growth model for pure liquids,an analyticasl model for nucleate pool boiling heat transfer of pure liquids on smooth tubes is developed.
Energy Technology Data Exchange (ETDEWEB)
Sesha Bamini, N., E-mail: seshabamini@hotmail.co [National Centre For Ultrafast Processes, University of Madras, Chennai, Tamil Nadu (India); Ramalingam, A.; Gowri, V.S. [Anna University, Chennai, Tamil Nadu (India)
2010-06-15
The spectral behaviour of the individual dyes (C480 and C535) is discussed. The absorption and fluorescence spectral profiles of the dyes, in solid and liquid environments, are identical. Dye doped polymer rods of donor dye (C480) without the acceptor dye (C535), acceptor dye (C535) without the donor dye (C480) and donor dye with acceptor dye at different acceptor concentrations are synthesized. Energy transfer technique is studied, in detail, using these rods. The results obtained are compared with their respective liquid mixtures. Optical gain of the acceptor dye with and without the donor dye is determined experimentally, in both solid and liquid media. The gain of the acceptor with donor increases and then decreases with increase in acceptor concentration. Both solid and liquid media show similar trends. But, the gain coefficient in the solid matrix is less than that in the liquid medium. The photobleaching of the dye doped polymer rod under nitrogen laser excitation is studied.
International Nuclear Information System (INIS)
Highlights: • Physical properties of the pure [EMim][MSO4] ionic liquid. • Physical and excess properties of its binary mixtures with alcohols. • The excess properties were fitted using the Redlich–Kister equation. • The effect of temperature on the VE, and KS,mE was analyzed. - Abstract: Experimental density, speed of sound, refractive index and viscosity data of the pure ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO4], were measured as a function of temperature from T = (293.15 to 343.15) K, every 5 K, and atmospheric pressure. Density, speed of sound and refractive index data were satisfactorily correlated with a linear equation, while viscosity data were fitted to the Vogel–Fulcher–Tamman (VFT) equation. Besides, from the experimental density values, the thermal expansion coefficient, α, was calculated. Furthermore, density and speed of sound for the binary systems of {methanol, or ethanol, or 1-propanol, or 2-propanol, or 1-butanol, or 1-pentanol + [EMim][MSO4]} were experimentally determined over the whole composition range, at T = (288.15, 298.15 and 308.15) K and p = 0.1 MPa. These properties were used to calculate the corresponding excess molar volumes and excess molar isentropic compressions, which were satisfactorily fitted to the Redlich–Kister equation. Finally, a comparison with available literature data was also carried out and the obtained results are discussed in terms of interactions and structure factors in these binary mixtures
International Nuclear Information System (INIS)
Highlights: • Solubility data for 10 molecular solvents in [BMPYR][TCB] are reported. • Excess enthalpies for 7 molecular solvents in [BMPYR][TCB] are given. • Thermodynamic modelling with PC-SAFT equation of state is presented. - Abstract: This paper presents a comprehensive thermodynamic study of binary mixtures formed by 1-butyl-1-methylpyrrolidinium tetracyanoborate ionic liquid and hydrocarbons (n-heptane, benzene, toluene, ethylbenzene), thiophene and alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol and 1-dodecanol). An impact of chemical structure of molecular compounds on their solubility in the ionic liquid and excess enthalpies of mixing is discussed. Furthermore, modelling of the measured properties by using perturbed-chain statistical associating fluid theory (PC-SAFT) is presented. The theory is applied in both correlative and semi-predictive mode involving temperature-dependent binary corrections fitted to infinite dilution activity coefficients. Solubility curves and excess enthalpies are captured by the model with a reasonable accuracy, when semi-predictive strategy is adopted. Moreover, (liquid + liquid) equilibrium phase diagram in ternary system composed of the investigated ionic liquid, thiophene and n-heptane is predicted with PC-SAFT and then the calculations are confronted with available experimental data. The results indicate that the approach proposed can be perceived as an interesting tool for reproducing the thermodynamic behaviour disclosed by such complex systems as those based on ionic liquids
Preparation and Characterization of Binary Mixture of Efavirenz and Nicotinamide
Directory of Open Access Journals (Sweden)
Erizal Zaini
2015-12-01
Full Text Available The purpose of this study was to prepare and characterize the binary mixture of efavirenz and nicotinamide. The binary mixture of efavirenz and nicotinamide (in equimolar ratio was prepared by solid state grinding and solvent dropped grinding. Characterizations were conducted by powder X-ray diffraction (PXRD, differential thermal analysis (DTA and scanning electron microscopy (SEM analysis. Interaction of efavirenz and nicotinamide in liquid states was studied by phase solubility profile. The dissolution rate studies was conducted by using USP type II apparatus in distilled water with 0.5 % sodium lauryl sulfate. Efavirenz dissolved was determined by high performance liquid chromatography (HPLC with Acetonitrile and acetic acid 1 % as mobile phase. The diffracgram of powder X-Ray analysis showed that both efavirenz and nicotinamide are highly crystalline, and equimolar binary mixtures showed a similar diffraction peaks. Thermal analysis result showed that binary mixture of efavirenz and nicotinamide form a simple eutectic mixture with the eutectic temperature (tE was 92.7 °C. The SEM analysis depicted that efavirenz and nicotinamide are polyhedral shaped particles, while binary mixture showed a homogenous aggregates of fine needle shaped particles. Phase solubility profile of the binary mixture indicated formation of a soluble complex between efavirenz and nicotinamide in 1:1 molar. The dissolution rate of the binary mixtures were significantly higher compared to the intact efavirenz.
Binary mixtures of chiral gases
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.
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.
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.
International Nuclear Information System (INIS)
Isothermal vapor liquid equilibria for the binary system of 3-methylpentane with ethylene glycol monopropyl ether (C3E1) and ethylene glycol isopropyl ether (iC3E1) were measured at 303.15, 318.15, and 333.15K. In our previous work, phase equilibria for the binary system of C3E1 mixtures were investigated according to the chain length of alkane, alcohol or those isomer. But in this study, we discussed the different effect of C3E1 and its isomer, iC3E1, 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 iC3E1 mixture system and the C3E1 mixture system
Fita, Piotr; Punzi, Angela; Vauthey, Eric
2009-01-01
The excited-state relaxation of malachite green and brilliant green in solvents of various viscosity has been investigated at liquid/liquid interfaces and in bulk solutions by surface second harmonic generation and transient absorption spectroscopy. Mixtures of water and glycerol in various proportions have been used as solvents of variable viscosity. Transient absorption measurements in bulk revealed that both dyes are suitable as a probe of local viscosity for water+glycerol mixtures and th...
International Nuclear Information System (INIS)
Highlights: • Formation of hemiacetal/poly(oxymethylene) hemiacetals in liquid binary mixtures. • Aldehyde (1-propanal or 1-butanal or 1-heptanal) and alcohol (methanol or ethanol or 1-propanol). • Quantitative 13C NMR spectroscopy at temperatures between (255 and 295) K. • High conversion rate to hemiacetals. • (1-Propanal + 1-propanol (50 + 50)) at 273 K: mole fraction of hemiacetal (polymers) ≈55% (≈6%). -- Abstract: The chemical reactions of aldehydes with alcohols to (hemiacetals and poly(oxymethylene) hemiacetals) have an essential influence on the thermodynamic properties and related phenomena like, for example, the vapor + liquid phase equilibrium of such liquid mixtures. This is well known in the literature for systems such as, for example, formaldehyde and methanol. Experimental information on the chemical reaction equilibria in mixtures with aldehydes other than formaldehyde and alcohols is extremely scarce. Therefore, in the first part of this series, quantitative NMR spectroscopy was used to investigate the chemical reaction equilibrium in binary liquid mixtures of acetaldehyde and an alcohol (methanol or ethanol or 1-propanol) at temperatures between (255 and 295) K. That work is here extended to three other aldehydes, viz. (1-propanal, 1-butanal and 1-heptanal). The results confirm the expectations from the first part of this series, i.e., that the majority of the constituents of the mixture is present as hemiacetal and the first two poly(oxymethylene) hemiacetals. For example, in an equimolar liquid mixture of {1-heptanal + methanol (or + ethanol or + 1-propanol)} at T = 273 K about 88% (or 81% for both other alcohols) of the aldehyde is bound to hemiacetal and the first two poly(oxymethylene) hemiacetals, i.e., the conversion rates are nearly the same as in the previous investigations with acetaldehyde instead of 1-heptanal. In the series investigated of combinations of aldehydes and alcohols, the particular aldehyde has only a small
Correlation of the liquid mixture viscosities
Directory of Open Access Journals (Sweden)
Knežević-Stevanović Anđela B.
2012-01-01
Full Text Available In this paper forty two selected correlation models for liquid mixture viscosities of organic compounds were tested on 219 binary and 41 ternary sets of experimental data taken from literature. The binary sets contained 3675 experimental data points for 70 different compounds. The ternary sets contained 2879 experimental data points for 29 different compounds. The Heric I, Heric-Brewer II, and Krishnan-Laddha models demonstrated the best correlative characteristics for binary mixtures (overall absolute average deviation < 2%. The Heric I, Heric-Brewer II, Krishnan-Laddha and Heric II models demonstrated the best correlative characteristics for ternary mixtures (overall absolute average deviation < 3%.
Ghosh, Surajit; Mandal, Sarthak; Banerjee, Chiranjib; Rao, Vishal Govind; Sarkar, Nilmoni
2012-08-01
The dynamics of photoisomerization of 3,3'-diethyloxadicarbocyanine iodide (DODCI) has been investigated inside micellar environment formed by a surfactant-like ionic liquid, 1-butyl-3-methylimidazolium octyl sulfate ([C(4)mim][C(8)SO(4)]) and also in binary mixture of another ionic liquid, N,N,N-trimethyl-N-propyl ammonium bis(trifluoromethanesulfonyl) imide, ([N(3111)][Tf(2)N]) with methanol, acetonitrile, and n-propanol by using steady-state and picosecond time-resolved fluorescence spectroscopy. The entrapment of DODCI into the [C(4)mim][C(8)SO(4)] micellar environment led to the enhanced fluorescence intensity along with ~13 nm red shift in the emission maxima. A sharp increase in the fluorescence quantum yield (Φ) and the lifetime (τ(f)) near the critical micelle concentration (cmc) range is observed followed by saturation at higher concentration. As a result of partitioning of the probe molecules in the micellar phase from water, the nonradiative rate constant (k(nr)) of DODCI decreases 2.7 times than in water. The retardation of isomerization rate is due to high microviscosity of the micellar system compared to bulk water. In order to understand how the rate of isomerization depends on polarity as well as viscosity, we have measured isomerization rate in neat [N(3111)][Tf(2)N] and its mixtures with polar solvents, like methanol, acetonitrile, and n-propanol. The addition of methanol and n-propanol increases the polarity, but viscosity of the medium decreases. The nonradiative rate constant that represents the rate of photoisomerization decreases with the addition of the polar solvent in [N(3111)][Tf(2)N]. Complete analysis of all the experimental results indicate that viscosity is the sole parameter that regulates the rate of photoisomerization. Temperature-dependent k(nr) are used to determine the activation energy (E(a)) in 100 mM [C(4)mim][C(8)SO(4)] solution and neat [N(3111)][Tf(2)N] system. PMID:22793684
Preparation and Characterization of Binary Mixture of Efavirenz and Nicotinamide
Erizal Zaini; Fitri Rachmaini; Fithriani Armin; Lili Fitriani
2015-01-01
The purpose of this study was to prepare and characterize the binary mixture of efavirenz and nicotinamide. The binary mixture of efavirenz and nicotinamide (in equimolar ratio) was prepared by solid state grinding and solvent dropped grinding. Characterizations were conducted by powder X-ray diffraction (PXRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM) analysis. Interaction of efavirenz and nicotinamide in liquid states was studied by phase solubility profil...
International Nuclear Information System (INIS)
Highlights: • The solubility was measured in (water + acetic acid) from 283.15 to 338.15 K. • The solubility increased with increasing temperature and water contents. • The modified Apelblat equation was more accurate than the λh equation. - Abstract: In this study, the solubility of 3-thiophenecarboxylic acid was measured in (water + acetic acid) binary solvent mixtures in the temperature ranging from 283.15 to 338.15 K by the analytical stirred-flask method under atmospheric pressure. The experimental data were well-correlated with the modified Apelblat equation and the λh equation. In addition, the calculated solubilities showed good agreement with the experimental results. It was found that the modified Apelblat equation could obtain the better correlation results than the λh equation. The experiment results indicated that the solubility of 3-thiophenecarboxylic acid in the binary solvents increased with increasing temperature, increases with increasing water contents, but the increments with temperature differed from different water contents. In addition, the thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van’t Hoff analysis. The experimental data and model parameters would be useful for optimizing the process of purification of 3-thiophenecarboxylic acid in industry
International Nuclear Information System (INIS)
Highlights: • Densities and viscosities of [TMG]IM + alcohol mixtures were measured. • Coefficient of thermal expansion, molecular volume, standard entropy, and lattice energy were obtained. • Excess molar volumes and viscosity deviations were calculated and fitted to Redlich–Kister equation. • Other volumetric properties and excess Gibbs free energy of activation for viscous flow were deduced. • The intermolecular interactions between [TMG]IM and alcohols were analyzed. - Abstract: Densities and viscosities of the pure ionic liquid 1,1,3,3-tetramethylguanidine imidazole ([TMG]IM) and its binary mixtures with methanol, ethanol, 1-propanol, and 1-butanol were measured at temperatures from T = (293.15 to 313.15) K. The thermal expansion coefficient, molecular volume, standard entropy, and lattice energy of [TMG]IM were obtained from the experimental density value. The temperature dependence of the viscosity of [TMG]IM was fitted to the fluidity equation. Excess molar volumes VE and viscosity deviations Δη of the binary mixtures were calculated and fitted to the Redlich–Kister equation with satisfactory results. The result shows that the VE values of the binary mixtures are negative over the whole composition range, while Δη values have an S-shape deviation. Temperature has little effect on the VE of the systems, but it has significant effect on the Δη. Furthermore, the absolute values of VE for {[TMG]IM (1) + alcohol (2)} systems at the same temperature decrease with increasing carbon alkyl chain of the primary alcohol. Other derived properties, such as the apparent molar volumes, partial molar volumes, excess partial molar volumes, Gibbs free energy of activation for viscous flow, and excess Gibbs free energy of activation for viscous flow of the above-mentioned systems were also calculated
International Nuclear Information System (INIS)
Highlights: • Thermo-physical properties of the pure ionic liquid were experimental determined. • Physical properties of binary mixtures (alcohol + ionic liquid) were measured. • From experimental data, excess properties (VE and KS,mE) were calculated. • The excess properties were fitted using the Redlich–Kister equation. • The effect of the ions and temperature on the VE and KS,mE was also discussed. -- Abstract: In this paper, experimental densities, speeds of sound, dynamic viscosities, refractive indices and molar isobaric heat capacities of the pure 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid, [PMpyr][NTf2], are reported as a function of temperature from T = (293.15 to 343.15) K and at atmospheric pressure. From density and refractive index data, the thermal expansion coefficient, molar refractions and molar refractions for the pure ionic liquid were calculated. Besides, a thermal analysis was carried out for the pure ionic liquid using a differential scanning calorimeter. Linear equations were used to fit the density, speed of sound, refractive index and molar isobaric heat capacity data, while the viscosity data were fitted using common equations such as Arrhenius, Vogel−Fulcher−Tamman (VFT), Litovitz, and fluidity. Furthermore, experimental density, speed of sound and refractive index data for binary mixtures with alcohols and their derived properties (excess molar volume, and excess molar isentropic compression) were determined over the whole composition range from T = (298.15, 303.15 and 308.15) K. The excess properties were satisfactorily fitted by Redlich–Kister equation
International Nuclear Information System (INIS)
Highlights: ► ρ, u, and HE of {[emim][BF4] + Py or α- or β- or γ-picoline} mixtures have been measured. ► The observed ρ and u data have been employed to determine VE and κSE. ► Graph theory has been utilized to predict VE, HE, and κSE data of the studied mixtures. - Abstract: The densities, ρ, speeds of sound, u of {1-ethyl-3-methylimidazolium tetrafluoroborate (i) + pyridine or α- or β- or γ-picoline (j)} at T/K = (293.15, 298.15, 303.15, and 308.15) and excess molar enthalpies, HE of the same set of mixtures at T/K = (298.15) have been measured over entire mole fraction range using DSA-5000 and 2-drop microcalorimeter. Excess molar volumes, VE and excess isentropic compressibilities, κSE values have been predicted by utilizing the measured densities and speeds of sound data. It has been observed that VE, HE, and κSE values for the studied mixtures are negative over entire composition. The connectivity parameter of third degree of a molecule, 3ξ (which in turn depends upon its topology) have been applied to predict (i) state of components of ionic liquid mixtures in their pure and mixed state; (ii) nature and extent of interactions existing in mixtures; and (iii) VE, HE, and κSE values. The analysis of VE data in terms of Graph theory (which deals with topology of a molecule) suggest that while 1-ethyl-3-methylimidazolium tetrafluoroborate is characterised by electrostatic forces of attraction and exist as monomer; α- or β- or γ-picoline exist as associated molecular entities. Further, (i + j) mixtures are characterized by interactions between nitrogen and florine atoms of 1-ethyl-3-methylimidazolium tetrafluoroborate with nitrogen and carbon atoms of pyridine or isomeric picolines to form 1:1 molecular complex. The IR studies also support to this view point. The VE, HE, and κSE values predicted by Graph theory compare well with experimental values.
PARTICLE SEGREGATION IN FLUIDIZED BINARY-MIXTURES
HOFFMANN, AC; JANSSEN, LPBM
1993-01-01
The particle segregation in fluidised beds consisting of different types of binary mixtures is shown to be governed by the same particle transport processes. The segregation behaviour of both ''different-density mixtures'' and ''equal-density mixtures'', two types of system which until now largely h
Stability limits in binary fluids mixtures.
Imre, Attila R; Kraska, Thomas
2005-02-01
The stability limits in binary fluid mixtures are investigated on the basis of the global phase diagram approach employing a model for the attracting hard-sphere fluid. In addition to the diffusion spinodals the mechanical spinodals are included. As a result one finds topologically different types of the diffusion spinodals while only one shape exists for the mechanical spinodals which are present in the region of liquid-vapor equilibria only. The diffusion spinodals represent the underlying properties of the phase behavior. The types of stable phase behavior therefore resemble that of the spinodal behavior. The different shapes of the spinodals can be important for nonequilibrium processes in nature and technology. PMID:15740388
Allen, Jesse J; Bowser, Sage R; Damodaran, Krishnan
2014-05-01
Interactions of ionic liquids (ILs) with water are of great interest for many potential IL applications. 1-Ethyl-3-methylimidazolium (emim) acetate, in particular, has shown interesting interactions with water including hydrogen bonding and even chemical exchange. Previous studies have shown the unusual behavior of emim acetate when in the presence of 0.43 mole fraction of water, and a combination of NMR techniques is used herein to investigate the emim acetate-water system and the unusual behavior at 0.43 mole fraction of water. NMR relaxometry techniques are used to describe the effects of water on the molecular motion and interactions of emim acetate with water. A discontinuity is seen in nuclear relaxation behavior at the concentration of 0.43 mole fraction of water, and this is attributed to the formation of a hydrogen bonded network. EXSY measurements are used to determine the exchange rates between the H2 emim proton and water, which show a complex dependence on the concentration of the mixture. The findings support and expand our previous results, which suggested the presence of an extended hydrogen bonding network in the emim acetate-water system at concentrations close to 0.50 mole fraction of H2O. PMID:24654003
DEFF Research Database (Denmark)
Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht; Stenby, Erling Halfdan
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...
SK. Fakruddin; Ch Srinivasu; K. Narendra
2014-01-01
The ultrasonic velocity , density and viscosity values have been measured experimentally in the binary mixture containing quinoline and p-xylene at different temperatures T(=303.15, 308.15,313.15 and 318.15)K over the entire range of composition. This experimental data have been *E used to calculate the excess Gibb's free energy function (G ).The results have been qualitatively used to explain the molecular interactions between the components of the liquid mixture.
International Nuclear Information System (INIS)
Explicit expressions of the self-diffusion coefficient, Di, and shear viscosity, ηsv, are presented for Lennard-Jones (LJ) binary mixtures in the liquid states along the saturated vapor line. The variables necessary for the expressions were derived from dimensional analysis of the properties: atomic mass, number density, packing fraction, temperature, and the size and energy parameters used in the LJ potential. The unknown dependence of the properties on each variable was determined by molecular dynamics (MD) calculations for an equimolar mixture of Ar and Kr at the temperature of 140 K and density of 1676 kg m−3. The scaling equations obtained by multiplying all the single-variable dependences can well express Di and ηsv evaluated by the MD simulation for a whole range of compositions and temperatures without any significant coupling between the variables. The equation for Di can also explain the dual atomic-mass dependence, i.e., the average-mass and the individual-mass dependence; the latter accounts for the “isotope effect” on Di. The Stokes-Einstein (SE) relation obtained from these equations is fully consistent with the SE relation for pure LJ liquids and that for infinitely dilute solutions. The main differences from the original SE relation are the presence of dependence on the individual mass and on the individual energy parameter. In addition, the packing-fraction dependence turned out to bridge another gap between the present and original SE relations as well as unifying the SE relation between pure liquids and infinitely dilute solutions
Energy Technology Data Exchange (ETDEWEB)
Ohtori, Norikazu, E-mail: ohtori@chem.sc.niigata-u.ac.jp [Department of Chemistry, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181 (Japan); Ishii, Yoshiki [Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181 (Japan)
2015-10-28
Explicit expressions of the self-diffusion coefficient, D{sub i}, and shear viscosity, η{sub sv}, are presented for Lennard-Jones (LJ) binary mixtures in the liquid states along the saturated vapor line. The variables necessary for the expressions were derived from dimensional analysis of the properties: atomic mass, number density, packing fraction, temperature, and the size and energy parameters used in the LJ potential. The unknown dependence of the properties on each variable was determined by molecular dynamics (MD) calculations for an equimolar mixture of Ar and Kr at the temperature of 140 K and density of 1676 kg m{sup −3}. The scaling equations obtained by multiplying all the single-variable dependences can well express D{sub i} and η{sub sv} evaluated by the MD simulation for a whole range of compositions and temperatures without any significant coupling between the variables. The equation for D{sub i} can also explain the dual atomic-mass dependence, i.e., the average-mass and the individual-mass dependence; the latter accounts for the “isotope effect” on D{sub i}. The Stokes-Einstein (SE) relation obtained from these equations is fully consistent with the SE relation for pure LJ liquids and that for infinitely dilute solutions. The main differences from the original SE relation are the presence of dependence on the individual mass and on the individual energy parameter. In addition, the packing-fraction dependence turned out to bridge another gap between the present and original SE relations as well as unifying the SE relation between pure liquids and infinitely dilute solutions.
Ohtori, Norikazu; Ishii, Yoshiki
2015-10-01
Explicit expressions of the self-diffusion coefficient, Di, and shear viscosity, ηsv, are presented for Lennard-Jones (LJ) binary mixtures in the liquid states along the saturated vapor line. The variables necessary for the expressions were derived from dimensional analysis of the properties: atomic mass, number density, packing fraction, temperature, and the size and energy parameters used in the LJ potential. The unknown dependence of the properties on each variable was determined by molecular dynamics (MD) calculations for an equimolar mixture of Ar and Kr at the temperature of 140 K and density of 1676 kg m-3. The scaling equations obtained by multiplying all the single-variable dependences can well express Di and ηsv evaluated by the MD simulation for a whole range of compositions and temperatures without any significant coupling between the variables. The equation for Di can also explain the dual atomic-mass dependence, i.e., the average-mass and the individual-mass dependence; the latter accounts for the "isotope effect" on Di. The Stokes-Einstein (SE) relation obtained from these equations is fully consistent with the SE relation for pure LJ liquids and that for infinitely dilute solutions. The main differences from the original SE relation are the presence of dependence on the individual mass and on the individual energy parameter. In addition, the packing-fraction dependence turned out to bridge another gap between the present and original SE relations as well as unifying the SE relation between pure liquids and infinitely dilute solutions.
International Nuclear Information System (INIS)
Highlights: • Mixtures of [bmim][BF4] or [emim][BF4] with methanol were studied. • Density, speed of sound, viscosity and refractive index were determined. • Excess volumes, isentropic compressibilities, properties deviations were calculated. • Properties excess and deviations were correlated with temperature and composition. - Abstract: Densities, speeds of sound, viscosities and refractive indices of two binary systems 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4] + methanol and 1-ethyl-3-methylimidazolium tetrafluoroborate [emim][BF4] + methanol, as well as of all pure components, have been measured covering the whole range of compositions at T = (278.15 to 318.15) K and p = 101 kPa. From this data, excess molar volumes, excess isentropic compressibilities, viscosity deviations and refractive index deviations were calculated and fitted to extended versions of the Redlich–Kister equation. Estimated coefficients of these equations taking into account the dependence on composition and temperature simultaneously were also presented
Leys, Jan; Losada-Pérez, Patricia; Troncoso, Jacobo; Glorieux, Christ; Thoen, Jan
2011-07-14
Dielectric constant measurements have been carried out in the one- and two-phase regions near the critical point of the polar + polar binary liquid mixture nitromethane + 3-pentanol. In the two-phase region, evidence for the |t|(2β) singularity in the coexistence-curve diameter has been detected, thus confirming the novel predictions of complete scaling theory for liquid-liquid criticality. In the one-phase region, an "unusual" negative sign for the amplitude of the |t|(1-α) singularity has been encountered for the first time in an upper critical solution temperature type of binary liquid mixture at atmospheric pressure. Mass density measurements have also been carried out to provide additional information related to such experimental finding, which entails an increase of the critical temperature T(c) under an electric field. PMID:21766958
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.
International Nuclear Information System (INIS)
Highlights: • VLE of (ethanol + glycerol), or (water + glycerol) binary mixtures were measured. • The investigated temperatures are (273 to 363 (or 353)) K. • The (ethanol + glycerol) binary system exhibits positive deviations in GE. • For (water + glycerol) binary system negative shape in GE is observed. • The NRTL, UNIQUAC and Modified UNIFAC (Do) models have been used. -- Abstract: The vapor pressures of (ethanol + glycerol) and (water + glycerol) binary mixtures were measured by means of two static devices at temperatures between (273 and 353 (or 363)) K. The data were correlated with the Antoine equation. From these data, excess Gibbs free energy functions (GE) were calculated for several constant temperatures and fitted to a fourth-order Redlich–Kister equation using the Barker method. The (ethanol + glycerol) binary system exhibits positive deviations in GE where for the (water + glycerol) mixture, the GE is negative for all temperatures investigated over the whole composition. Additionally, the NRTL, UNIQUAC and Modified UNIFAC (Do) models have been used for the correlation or prediction of the total pressure
International Nuclear Information System (INIS)
Highlights: ► Physical and osmotic properties of binary mixtures {alcohol + [BMim][dca]} were measured. ► From experimental data, apparent molar properties and osmotic coefficients were calculated. ► The apparent properties were fitted using a Redlich–Meyer type equation. ► The osmotic coefficients were correlated using the Extended Pitzer and the MNRTL models. - Abstract: In this paper, densities and speeds of sound for five binary systems {alcohol + 1-butyl-3-methylimidazolium dicyanamide} were measured from T = (293.15 to 323.15) K and atmospheric pressure. From these experimental data, apparent molar volume and apparent molar isentropic compression have been calculated and fitted to a Redlich–Meyer type equation. This fit was also used to calculate the apparent molar volume and apparent molar isentropic compression at infinite dilution for the studied binary mixtures. Moreover, the osmotic and activity coefficients and vapor pressures of these binary mixtures were also determined at T = 323.15 K using the vapor pressure osmometry technique. The experimental osmotic coefficients were correlated using the Extended Pitzer model of Archer. The mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures were calculated from the parameters obtained in the correlation.
Bribesh, Fathi A. M.; Madruga, Santiago
2016-03-01
We present steady non-linear solutions of films of confined polymer blends deposited on a solid substrate at off-critical concentrations with a free deformable surface. The solutions are obtained numerically using a variational form of the Cahn-Hilliard equation in the static limit, which allows for internal diffuse interfaces between the two components of the mixture. Existence of most of the branches of non-linear solutions at off-critical concentrations can be predicted from the knowledge of the branching points obtained with a linear stability analysis plus the non-linear solutions at critical concentrations. However, some families of solutions are found not to have correspondence at critical compositions. We take a value for surface tension that allows strong deformations at the sharp free upper surface. Varying the average composition and the length and thickness of the films we find a rich morphology of static films in the form of laterally structure films, layered films, droplets on the substrate, droplets at the free surface, and checkerboard structures. We show that laterally structured solutions are energetically favorable over homogeneous and other structured solutions within the whole spinodal region and even close to the absolute stability binodal boundary.
Sujata S. Patil; Sunil R. Mirgane; Balasaheb R. Arbad
2014-01-01
Densities and viscosities for the four binary liquid mixtures of methyl acrylate, ethyl acrylate, butyl acrylate and methyl methacrylate with hexane-1-ol at temperatures 303.15 and 313.15 K and at atmospheric pressure were measured over the entire composition range. These values were used to calculate excess molar volumes and deviation in viscosities which were fitted to Redlich–Kister polynomial equation. Recently proposed Jouyban Acree model was also used to correlate the experimental value...
Directory of Open Access Journals (Sweden)
Daming Gao
2012-01-01
Full Text Available Vapor-liquid equilibrium (VLE data for the strongly associated ternary system methanol + water + ethanoic acid and the three constituent binary systems have been determined by the total pressure-temperature-liquid-phase composition-molar excess enthalpy of mixing of the liquid phase (p, T, x, HmE for the binary systems using a novel pump ebulliometer at 101.325 kPa. The vapor-phase compositions of these binary systems had been calculated from Tpx and HmE based on the Q function of molar excess Gibbs energy through an indirect method. Moreover, the experimental T, x data are used to estimate nonrandom two-liquid (NRTL, Wilson, Margules, and van Laar model parameters, and these parameters in turn are used to calculate vapor-phase compositions. The activity coefficients of the solution were correlated with NRTL, Wilson, Margules, and van Laar models through fitting by least-squares method. The VLE data of the ternary system were well predicted from these binary interaction parameters of NRTL, Wilson, Margules, and van Laar model parameters without any additional adjustment to build the thermodynamic model of VLE for the ternary system and obtain the vapor-phase compositions and the calculated bubble points.
Spinodal decomposition of chemically reactive binary mixtures
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.
Modified Sonine approximation for granular binary mixtures
Garzó, Vicente; Reyes, Francisco Vega; Montanero, José María
2008-01-01
We evaluate in this work the hydrodynamic transport coefficients of a granular binary mixture in $d$ dimensions. In order to eliminate the observed disagreement (for strong dissipation) between computer simulations and previously calculated theoretical transport coefficients for a monocomponent gas, we obtain explicit expressions of the seven Navier-Stokes transport coefficients with the use of a new Sonine approach in the Chapman-Enskog theory. Our new approach consists in replacing, where a...
Prediction of saturated liquid enthalpy of refrigerant mixtures
Institute of Scientific and Technical Information of China (English)
CHEN ZeShao; CHEN JianXin; HU Peng
2007-01-01
New corresponding temperature and corresponding enthalpy of refrigerant mixtures were defined. The relationship between saturated liquid corresponding enthalpy and corresponding temperature of refrigerant mixtures accorded with that of pure components. The characteristic parameters of saturated liquid enthalpy difference of refrigerant mixtures were calculated by three methods according to the different application conditions. The generalized equation of saturated liquid enthalpy of refrigerant mixtures was presented. The calculated values were compared with the values in literature for five ternary and binary refrigerant mixtures, namely R404A, R407A, R407B, R32/R134a, and R410A. The overall average absolute deviation was less than 1.0%.
Trejbal, Jiří
2009-04-01
Vapor-liquid equilibria of mixtures of 1,4-diazabicyclo[2.2.2]octane with ethylenediamine, ethanolamine, and ethylene glycol were studied. Ideal behavior in the ethylenediamine and 1,4-diazabicyclo[2.2.2]octane mixture was observed. Ethanolamine and 1,4-diazabicyclo[2.2.2]octane form an azeotrope with a minimum boiling point whereas ethylene glycol and 1,4-diazabicyclo[2.2.2]octane form an azeotrope with a maximum boiling point. Non-ideal behavior of the mixtures was described by the NRTL equation, and the corresponding constants were calculated.
Energy Technology Data Exchange (ETDEWEB)
Falcon, J.; Ortega, J.; Gonzalez, E. [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica
1996-07-01
Densities and excess volumes were determined at 298.15 K for propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol. The results of those quantities were then correlated to get the concentrations of vapor-liquid equilibrium obtained isobarically at 160 kPa for the same mixtures. Two mixtures show azeotropes: for propyl methanoate (1) + ethanol (2), x{sub 1} = 0.443 at T = 358.7 K; and for propyl methanoate (1) + propan-1-ol (2), x{sub 1} = 0.762 at T = 368.2 K. The mixtures are thermodynamically consistent, and the predictions made using several group-contribution models are satisfactory.
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
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 + ...
Shear viscosity of binary mixtures: The Gay-Berne potential
Khordad, R.
2012-05-01
The Gay-Berne (GB) potential model is an interesting and useful model to study the real systems. Using the potential model, we intend to examine the thermodynamical properties of some anisotropic binary mixtures in two different phases, liquid and gas. For this purpose, we apply the integral equation method and solve numerically the Percus-Yevick (PY) integral equation. Then, we obtain the expansion coefficients of correlation functions to calculate the thermodynamical properties. Finally, we compare our results with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, benzene + methanol, cyclohexane + ethanol, benzene + ethanol, carbon tetrachloride + ethyl acetate, and methanol + ethanol]. The results show that the GB potential model is capable for predicting the thermodynamical properties of binary mixtures with acceptable accuracy.
Shear viscosity of binary mixtures: The Gay–Berne potential
International Nuclear Information System (INIS)
Highlights: ► Most useful potential model to study the real systems is the Gay–Berne (GB) potential. ► We use GB model to examine thermodynamical properties of some anisotropic binary mixtures in two different phases. ► The integral equation methods are applied to solve numerically the Percus–Yevick (PY) equation. ► We obtain expansion coefficients of correlation functions needed to calculate the properties of studied mixtures. ► The results are compared with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, etc.] - Abstract: The Gay–Berne (GB) potential model is an interesting and useful model to study the real systems. Using the potential model, we intend to examine the thermodynamical properties of some anisotropic binary mixtures in two different phases, liquid and gas. For this purpose, we apply the integral equation method and solve numerically the Percus–Yevick (PY) integral equation. Then, we obtain the expansion coefficients of correlation functions to calculate the thermodynamical properties. Finally, we compare our results with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, benzene + methanol, cyclohexane + ethanol, benzene + ethanol, carbon tetrachloride + ethyl acetate, and methanol + ethanol]. The results show that the GB potential model is capable for predicting the thermodynamical properties of binary mixtures with acceptable accuracy.
Directory of Open Access Journals (Sweden)
Sujata S. Patil
2014-12-01
Full Text Available Densities and viscosities for the four binary liquid mixtures of methyl acrylate, ethyl acrylate, butyl acrylate and methyl methacrylate with hexane-1-ol at temperatures 303.15 and 313.15 K and at atmospheric pressure were measured over the entire composition range. These values were used to calculate excess molar volumes and deviation in viscosities which were fitted to Redlich–Kister polynomial equation. Recently proposed Jouyban Acree model was also used to correlate the experimental values of density and viscosity. The mixture viscosities were correlated by several semi-empirical approaches like Hind, Choudhary–Katti, Grunberg–Nissan, Tamura and Kurata, McAllister three and four body model equations. A graphical representation of excess molar volumes and deviation in isentropic compressibility shows positive nature whereas deviation in viscosity shows negative nature at both temperatures for all four binary liquid mixtures. Positive values of excess molar volumes show that volume expansion is taking place causing rupture of H-bonds in self associated alcohols. The results were discussed in terms of molecular interactions prevailing in the mixtures.
International Nuclear Information System (INIS)
Highlights: • Coefficients of compressibility of liquid binary mixture (water + glycerol) were measured. • Partial molar volumes of the components and excess molar volumes of the mixture were calculated. • Molar isothermal compression, molar isobaric expansion and molar isochoric elasticity of the mixture were evaluated. • Analysis of volume characteristics confirms glycerol hydrophilic nature. - Abstract: The coefficients of compressibility, k = ΔV/Vo, of liquid binary mixture of {water (1) + glycerol (2)} were measured over the whole composition range at pressures from (0.1 to 100) MPa and temperatures from (278.15 to 323.15) K. Excess molar volumes of the mixture, VmE, partial molar volumes of the mixture components, V¯i, as well as their limiting values, molar isothermal compression KT,m, molar isobaric expansion EP,m, molar isochoric elasticity (isochoric coefficient of thermal pressure) βm were calculated. It was revealed that with glycerol molar fraction increasing the coefficients of compressibility, k, decreased to x2 ≈ 0.3 ÷ 0.4 (where x2 was glycerol molar fraction), and further changed insignificantly. It was shown that all isobars of excess molar volumes were negative and their absolute values, VmE, decreased on temperature and pressure rising. No extremes were observed on concentration dependences of partial molar volumes of glycerol in the mixture at its low concentrations. Under the state parameters studied limiting partial volumes of water and glycerol decrease with pressure rising but increase with temperature growth. Dependences of molar isothermal compression and molar isochoric elasticity on glycerol molar fraction passed extremes, and similar dependences of molar isobaric expansion had the temperature inversion regions
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.
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. PMID:18969525
Institute of Scientific and Technical Information of China (English)
张冰; 陈松; 陈亮
2012-01-01
The kinematic viscosity, electrochemical window and electric conductivity of BMimBF4and BMimPF6 and their binary composite ionic liquids mixtures were studied. The results indicated that, physical and chemical properties of binary composite ionic liquids mixtures were changed by way of simply regulating volume of BMimBF4 and BMimPF6, which brought designing ionic liquids into full play and opened a new way for the application of ＂green solvent＂ - ionic liauids.%研究了BMimBF4、BMimPF6及其二者不同体积比复合离子液体的运动粘度、电化学窗口及电导率。结果表明,通过简单地调节BMimBF4和BMimPF6的复合体积比,可以改变BMimBF4和BMimPF6二元复合离子液体的物理化学性质,充分发挥离子液体的＂可设计＂性,为＂绿色溶剂＂离子液体的应用开辟了新的道路。
Small Scale Evaporation Kinetics of a Binary Fluid Mixture
Basdeo, Carl; Ye, Dezhuang; Kalonia, Devendra; Fan, Tai-Hsi; Mechanical Engineering Team; Pharmaceutical Sciences Collaboration
2013-03-01
Evaporation induces a concentrating effect in liquid mixtures. The transient process has significant influence on the dynamic behaviors of a complex fluid. To simultaneously investigate the fluid properties and small-scale evaporation kinetics during the transient process, the quartz crystal microbalance is applied to a binary mixture droplet of light alcohols including both a single volatile component (a fast evaporation followed by a slow evaporation) and a mixture of two volatile components with comparable evaporation rates. The density and viscosity stratification are evaluated by the shear wave, and the evaporation kinetics is measured by the resonant signature of the acoustic p-wave. The evaporation flux can be precisely determined by the resonant frequency spikes and the complex impedance. To predict the concentration field, the moving interface, and the precision evaporation kinetics of the mixture, a multiphase model is developed to interpret the complex impedance signals based on the underlying mass and momentum transport phenomena. The experimental method and theoretical model are developed for better characterizing and understanding of the drying process involving liquid mixtures of protein pharmaceuticals.
Flash-Point prediction for binary partially miscible aqueous-organic mixtures
Liaw, Horng-Jang; Chen, Chien Tsun; Gerbaud, Vincent
2008-01-01
Flash point is the most important variable used to characterize fire and explosion hazard of liquids. Herein, partially miscible mixtures are presented within the context of liquid-liquid extraction processes and heterogeneous distillation processes. This paper describes development of a model for predicting the flash point of binary partially miscible mixtures of aqueous-organic system. To confirm the predictive efficiency of the derived flash points, the model was verified by comparing the ...
International Nuclear Information System (INIS)
Highlights: → An autoclave apparatus was used for binary (vapour + liquid) equilibrium data measurement. → The studied systems are polyethylene glycol mono-4-nonylphenyl ether with alcohols. → The saturated pressure data were fitted accurately to the Antoine equation. → The NRTL model correlated well the phase equilibrium data. → The solvent activities have been calculated. - Abstract: Saturated pressures of three binary systems of oligomeric polyethylene glycol mono-4-nonylphenyl ether (PEGNPE) with methanol, ethanol, and 2-propanol have been measured by using an autoclave (vapour + liquid) equilibrium (VLE) apparatus at temperatures ranging from (340 to 455) K and the oligomer content ranging from 0.100 to 0.400 in mole fraction. With a given feed composition, equilibrium pressures were measured at various temperatures to obtain VLE data. The experimental data were fitted to the Antoine equation and also correlated with activity coefficient models, the NRTL and the UNIQUAC. The correlation results showed good agreement between the calculated values and the experimental data. In general, the NRTL model yielded better results. Additionally, the solvent activities were evaluated from the experimental results and were compared with those from the NRTL and the UNIQUAC models.
International Nuclear Information System (INIS)
Research highlights: → The density and surface tension of [emim][L-lactate]) ionic liquid were determined. →The thermophysical properties of pure [emim][L-lactate] were investigated. → Density and surface tension were measured for [emim][L-lactate] + water binary system. → Excess molar volumes VE and the surface tension deviations δγ have been determined. - Abstract: The density and surface tension of 1-ethyl-3-methylimidazolium L-lactate ([emim][L-lactate]) ionic liquid were determined from T = (283.15 to 333.15) K. The coefficients of thermal expansion were calculated from the experimental density results using an empirical correlation for T = (283.15 to 333.15) K. Molecular volume and standard entropies of the IL were calculated from the experimental density values. The surface properties of IL were investigated. The critical temperature and enthalpy of vaporization were also discussed. Density and surface tension have been measured over the whole composition range for {[emim][L-lactate] + water} binary systems at a temperature of 298.15 K and atmospheric pressure. Excess molar volumes VE and the surface tension deviations δγ have been determined.
Solubility of anthracene in binary alcohol + 2-propoxyethanol solvent mixtures
Energy Technology Data Exchange (ETDEWEB)
McHale, M.E.R.; Powell, J.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1996-03-01
Solid-liquid equilibrium data of organic nonelectrolyte systems are becoming increasingly important in the petroleum industry, particularly in light of present trends toward heavier feedstocks and known carcinogenicity/mutagenicity of many of the larger polycyclic aromatic compounds. Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing 2-propoxyethanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 1-octanol, and 3-methyl-1-butanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.
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.
A classification system for tableting behaviors of binary powder mixtures
Changquan Calvin Sun
2016-01-01
The ability to predict tableting properties of a powder mixture from individual components is of both fundamental and practical importance to the efficient formulation development of tablet products. A common tableting classification system (TCS) of binary powder mixtures facilitates the systematic development of new knowledge in this direction. Based on the dependence of tablet tensile strength on weight fraction in a binary mixture, three main types of tableting behavior are identified. Eac...
Microscopic dynamics of binary mixtures and quasi-colloidal systems
International Nuclear Information System (INIS)
In the study on the title subject two questions are addressed. One is whether the microscopic dynamics of binary mixtures and quasi-colloidal systems can be understood theoretically with kinetic theories for equivalent hard sphere mixtures. The other question that arises is whether the similarity in the dynamics of dense simple fluids and concentrated colloidal suspensions also holds for binary mixtures and quasi-colloidal systems. To answer these questions, we have investigated a number of binary gas mixtures and quasi-colloidal system with different diameter ratios and concentrations. We obtain the experimental dynamic structure factors Sexpt(κ,ω) of the samples from inelastic neutron scattering. We compare Sexpt(κ,ω) with the dynamic structure SHS(κ,ω) of an equivalent hard sphere fluid, that we calculate with the Enskog theory. In chapter 2, 3 and 4 we study dense He-Ar gas mixtures (diameter ratio R=1.4, and mass ratio M=10) at low and high Ar concentrations. Experiment and kinetic theory are in good agreement. In chapter 5 we study dilute quasi-colloidal suspensions of fullerene C60 molecules dissolved in liquid CS2. The diameter ratio R=2.2 is larger than in previous experiments while the mass ratio M=9.5 is more or less the same. We obtain the self diffusion coefficient DS of one C60 molecule in CS2 and find Ds≤DSE≤DE, with DE obtained from kinetic theory and DSE from the Stokes-Einstein description. It appears that both descriptions are relevant but not so accurate. In chapter 6 we study three dense mixtures of neopentane in 40Ar (diameter ratio R=1.7, mass ratio M=2) at low and high neopentane concentrations. At low concentration, we find a diffusion coefficient of neopentane in Ar, which is in good agreement with kinetic theory and in moderate agreement with the Stokes-Einstein description. At high concentration the collective translational dynamics of neopentane shows a similar behaviour as in dense colloids and simple fluids. The results are
Energy landscape view of nonideality in binary mixtures.
Abraham, Sneha Elizabeth; Chakrabarti, Dwaipayan; Bagchi, Biman
2007-02-21
Positive and negative deviations from the prediction of Raoult's Law on the composition dependence of a property of binary mixtures are often explained in terms of structure formation and structure breakage, respectively, upon mixing. However, a detailed theoretical description of these ideas seems to be lacking in the literature. Here we present the energy landscape view of nonideality of the viscosity of the binary mixture using two different models, one for structure former and the other for structure breaker. For both the models, the average inherent structure energy shows an inverse correlation with the viscosity. The inherent structures of the structure former indicate that there is a considerable enhancement of short range order due to stronger attractive interaction between the two constituent species. On the other hand, for the structure breaker, there is no such enhancement of short range order due to weaker interaction between the two constituent species. We find the inherent structures of the structure breaker to be phase separated in many cases where the parent phase is homogeneous. When the configurational entropy of the parent liquid is computed for the two model systems, we find that the configurational entropy also shows an inverse correlation with the viscosity in both the cases. PMID:17328614
Thermodiffusion in binary and ternary nonpolar hydrocarbon + alcohol mixtures
Eslamian, Morteza; Saghir, M. Ziad
2012-12-01
Thermodiffusion in complex mixtures, such as associating, molten metal, and polymer mixtures is difficult to model usually owing to the occurrence of a sign change in the thermodiffusion coefficient when the mixture concentration and temperature change. A mixture comprised of a nonpolar hydrocarbon and an alcohol is a complex and highly non-ideal mixture. In this paper an existing binary non-equilibrium thermodynamics model (Eslamian and Saghir, Physical Review E 80, 061201, 2009) developed for aqueous mixtures of alcohols is examined against the experimental data of binary nonpolar hydrocarbon and alcohol mixtures. For ternary mixtures, non-equilibrium thermodynamic expressions developed by the authors for aqueous mixtures of alcohols (Eslamian and Saghir, Canadian Journal of Chemical Engineering, DOI 10.1002/cjce.20581) is used to predict thermodiffusion coefficients of ternary nonpolar hydrocarbon and alcohol mixtures. The rationale behind the sign change is elucidated and attributed to an anomalous change in the molecular structure and therefore viscosity of such mixtures. Model predictions of thermodiffusion coefficients of binary mixtures predict a sign change consistent with the experimental data although the model is still too primitive to capture all structural complexities. For instance, in the methanol-benzene mixture where the model predictions are poorest, the viscosity data show that when concentration varies, the mixture's molecular structure experiences a severe change twice, the first major change leading to a maximum in the thermodiffusion coefficient, whereas the second change causes a sign change.
Effective Potential and Interdiffusion in Binary Ionic Mixtures
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.
Stability studies of colloidal silica dispersions in binary solvent mixtures
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...
Yıldız, Sevtap; ćetinkaya, Mehmet Can; Üstünel, Şenay; Özbek, Haluk; Thoen, Jan
2016-06-01
We report optical birefringence data for a series of mixtures of the liquid crystals octylcyanobiphenyl (8CB) and decylcyanobiphenyl (10CB). Nematic order parameter S data in the nematic and smectic A phases have been derived from phase angle changes obtained in temperature scans with a rotating analyzer method. These S values have been used to arrive at values for possible entropy discontinuities at the smectic A to nematic phase transition temperature TN A. The 10CB mole fraction dependence of the obtained entropy discontinuities could be well fitted with a crossover function consistent with the mean-field free-energy expression with a nonzero cubic term arising from the coupling between the smectic-A order parameter and the orientational order parameter director fluctuations in the Halperin-Lubensky-Ma theory. The obtained results are in good agreement with existing results from adiabatic scanning calorimetry. By exploiting the fact that the temperature derivative of the order parameter S (T ) near TN A exhibits the same power law divergence as the specific heat capacity, we have extracted the effective critical exponent α values for the compositions under study. The critical exponent α has been observed to reach the tricritical value αTCP=0.5 for the 10CB mole fraction of x =0.330 .
Trokhymchuk; Orozco; Pizio; Vlachy
1998-11-15
The thermodynamics of a two-component fluid with a hard core interaction and screened Coulomb (Yukawa) interaction between particles, similar to the primitive model of an electrolyte solution, adsorbed in a disordered matrix of hard spheres, is studied by using replica Ornstein-Zernike integral equations and the mean spherical approximation (MSA). The gas-liquid transition is localized. The coexistence curve is investigated dependent on the range of interaction between fluid species, on matrix density, and on fluid-matrix attraction. We have observed shrinking of the coexistence envelope with increasing matrix density. The critical temperature of adsorbed mixture decreases with increasing matrix density. The critical density is less affected; however, it also decreases slightly. The critical temperature is sensitive to the fluid species-matrix attraction and depends nonmonotonously on their strength. For a given matrix microporosity, it increases slightly and then decreases with augmenting strength of fluid-matrix attraction. The critical density is less affected by this attraction. However, it decreases for the model with a sufficiently long-range tail of fluid-matrix attraction. Copyright 1998 Academic Press. PMID:9792783
Hydrodynamics for a granular binary mixture at low density
Garzó, Vicente; Dufty, J.W.
2001-01-01
Hydrodynamic equations for a binary mixture of inelastic hard spheres are derived from the Boltzmann kinetic theory. A normal solution is obtained via the Chapman-Enskog method for states near the local homogeneous cooling state. The mass, heat, and momentum fluxes are determined to first order in the spatial gradients of the hydrodynamic fields, and the associated transport coefficients are identified. In the same way as for binary mixtures with elastic collisions, these coefficients are det...
Anomalous orientational relaxation of solute probes in binary mixtures
Bhattacharyya, Sarika; Bagchi, Biman
2001-01-01
The orientation of a solute probe in a binary mixture often exhibits multiple relaxation times at the same solvent viscosity but different compositions [Beddard et al., Nature (London) 294, 145 (1981)]. In order to understand this interesting observation, we have carried out (NPT) molecular dynamics simulation study of rotation of prolate ellipsoids in binary mixtures. The simulations show that for a broad range of model parameters the experimental behavior can be reproduced. The plot of orie...
3种离子液体与甲霜灵二元混合物的联合毒性%Joint toxicities of three binary mixture between metalaxyl and ionic liquid
Institute of Scientific and Technical Information of China (English)
王成林; 张瑾; 刘树深; 刘海玲
2012-01-01
Selecting three imidazolium-based ionic liquids (ILs), C10H19CIN2 (IL1), C12H23CIN2 (IL2), and C16H31CIN2 (IL3), and metalaxyl (MET) as the mixture components, three groups of binary mixture, MET-IL1, MET -IL2, and MET-IL3, were designed by using the direct equipartition ray design procedure. The toxicities of the individual chemicals and binary mixtures to Vibrio qinghaiensis sp.-Q67 were determined by the microplate toxicity analysis (MTA). The toxicity interaction was evaluated by comparing the toxicity observed to that predicted by the concentration addition (CA) model and employing the isobologram at median effect concentration (EC50). The toxicity interactions of three groups of binary mixtures were significantly different. In the binary mixtures of MET-IL1 and MET-IL2, the higher the concentration ratio of MET was, the more obvious the antagonism. However, the toxicity interaction in the MET-IL3 mixtures was additive for the high concentration ratio of MET and synergistic for the low concentration ratio of MET. The lower the ratio of MET was, the stronger the synergistic action was.%选择3种咪唑类离子液体(ILs):C10H19CIN2(IL1),C12H23C1N2(IL2),C16H31C1N2(IL3)和一种杀菌剂甲霜灵(MET)为混合物组分,以直接均分射线法构建3组二元混合物体系:MET-IL1,MET-IL2和MET-IL3.应用微板毒性分析法(MTA)测定二元混合物对青海弧菌Q67(Hbrio qinghaiensis sp.-Q67)的联合毒性.通过比较实验毒性数据与浓度加和(CA)参考模型分析混合物的毒性相互作用,并利用半数效应浓度(EC50)水平下的等效线图分析毒性变化规律.结果表明3组二元混合物的相互作用明显不同.在MET-IL1和MET-IL2 2组二元体系中,MET浓度比例越高,拮抗作用越明显;在MET-IL3二元体系中,随着MET浓度比例的减小,MET与IL3的相互作用由加和变为协同,并且MET比例越小,协同作用越明显.
Gençaslan, Mustafa; Keskin, Mustafa
2016-09-01
We investigate critical curves and global phase behavior of unequal size of molecules in binary gas-liquid mixtures at the van Laar point and its vicinity. The van Laar point is only point at which the mathematical double point curve is stable, and also the intersection of the tricritical point and the double critical end point. The critical line structure is displayed for various combinations of the chain length and system parameters in the reduced pressure (P∗) temperature (T∗) plane, as is usually done with experimental results and temperature-concentration (T, x) plane. The P∗,T∗ diagrams are discussed in accordance with the Scott and van Konynenburg binary phase diagram classification. We found that our P∗,T∗ plots correspond to the type II, type III, type IV phase diagram behaviors and they are in good agreement with the theoretical and experimental studies. It is also found that the critical lines and phase behavior are extremely sensitive to small modifications in the system parameters.
Prediction of saturated liquid enthalpy of refrigerant mixtures
Institute of Scientific and Technical Information of China (English)
2007-01-01
New corresponding temperature and corresponding enthalpy of refrigerant mix- tures were defined. The relationship between saturated liquid corresponding en- thalpy and corresponding temperature of refrigerant mixtures accorded with that of pure components. The characteristic parameters of saturated liquid enthalpy dif- ference of refrigerant mixtures were calculated by three methods according to the different application conditions. The generalized equation of saturated liquid en- thalpy of refrigerant mixtures was presented. The calculated values were compared with the values in literature for five ternary and binary refrigerant mixtures, namely R404A, R407A, R407B, R32/R134a, and R410A. The overall average absolute devia- tion was less than 1.0%.
Thermodynamic studies of mixtures for topical anesthesia: Lidocaine-salol binary phase diagram
International Nuclear Information System (INIS)
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 oC with an enthalpy of 17.3 ± 0.5 kJ mol-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.
Drag Coefficient of a Spherical Droplet Immersed in a Near-Critical Binary Fluid Mixture
Fujitani, Youhei
2014-02-01
We consider a spherical liquid droplet immersed in a near-critical binary fluid mixture. A weak preferential attraction is assumed between the droplet and one of the two mixture components, and the difference in the viscosity is neglected between the mixture components. Using the Gaussian free-energy functional, we calculate the drag coefficient of a droplet. Whether it is increased or decreased by the preferential attraction turns out to depend on the bulk correlation length and the ratio of the viscosity of the surrounding mixture to that of the droplet.
Sarkar, Sarmistha; Bagchi, Biman
2011-03-01
An energy landscape view of phase separation and nonideality in binary mixtures is developed by exploring their potential energy landscape (PEL) as functions of temperature and composition. We employ molecular dynamics simulations to study a model that promotes structure breaking in the solute-solvent parent binary liquid, at low temperatures. The PEL of the system captures the potential energy distribution of the inherent structures (IS) of the system and is obtained by removing the kinetic energy (including that of intermolecular vibrations). The broader distribution of the inherent structure energy for structure breaking liquid than that of the structure making liquid demonstrates the larger role of entropy in stabilizing the parent liquid of the structure breaking type of binary mixtures. At high temperature, although the parent structure of the structure breaking binary mixture is homogenous, the corresponding inherent structure is found to be always phase separated, with a density pattern that exhibits marked correlation with the energy of its inherent structure. Over a broad range of intermediate inherent structure energy, bicontinuous phase separation prevails with interpenetrating stripes as signatures of spinodal decomposition. At low inherent structure energy, the structure is largely phase separated with one interface where as at high inherent structure energy we find nucleation type growth. Interestingly, at low temperature, the average inherent structure energy () exhibits a drop with temperature which signals the onset of crystallization in one of the phases while the other remains in the liquid state. The nonideal composition dependence of viscosity is anticorrelated with average inherent structure energy. PMID:21517506
Sarkar, Sarmistha; Bagchi, Biman
2011-03-01
An energy landscape view of phase separation and nonideality in binary mixtures is developed by exploring their potential energy landscape (PEL) as functions of temperature and composition. We employ molecular dynamics simulations to study a model that promotes structure breaking in the solute-solvent parent binary liquid, at low temperatures. The PEL of the system captures the potential energy distribution of the inherent structures (IS) of the system and is obtained by removing the kinetic energy (including that of intermolecular vibrations). The broader distribution of the inherent structure energy for structure breaking liquid than that of the structure making liquid demonstrates the larger role of entropy in stabilizing the parent liquid of the structure breaking type of binary mixtures. At high temperature, although the parent structure of the structure breaking binary mixture is homogenous, the corresponding inherent structure is found to be always phase separated, with a density pattern that exhibits marked correlation with the energy of its inherent structure. Over a broad range of intermediate inherent structure energy, bicontinuous phase separation prevails with interpenetrating stripes as signatures of spinodal decomposition. At low inherent structure energy, the structure is largely phase separated with one interface where as at high inherent structure energy we find nucleation type growth. Interestingly, at low temperature, the average inherent structure energy () exhibits a drop with temperature which signals the onset of crystallization in one of the phases while the other remains in the liquid state. The nonideal composition dependence of viscosity is anticorrelated with average inherent structure energy.
Spectrophotometric determination of volautile inorganic hydrides in binary gaseous mixtures
International Nuclear Information System (INIS)
A study was made on possibility of single and continuons analysis of binary mixtures (hydride-gas) for the content of volatile inorganic hydrides (VIH) from absorption spectra in the 185-280 nm band. Dependences of the percentage of VIH transmission on the wavelength are presented. It is shown that the maximum of their absorption depends on the element-hydrogen the bond length and binding energy. Detection limit for boron hydride was established to be n x 10-3% vol at 185-190 nm wavelength. Technique for spectrophotometric hydride determination in binary mixtures with hydrogen, argon, helium was developed. The technique provides the continuous control of gaseous mixture composition
Liquid class predictor for liquid handling of complex mixtures
Seglke, Brent W.; Lekin, Timothy P.
2008-12-09
A method of establishing liquid classes of complex mixtures for liquid handling equipment. The mixtures are composed of components and the equipment has equipment parameters. The first step comprises preparing a response curve for the components. The next step comprises using the response curve to prepare a response indicator for the mixtures. The next step comprises deriving a model that relates the components and the mixtures to establish the liquid classes.
Shear-induced quench of long-range correlations in a liquid mixture
Wada, Hirofumi
2003-01-01
A static correlation function of concentration fluctuations in a (dilute) binary liquid mixture subjected to both a concentration gradient and uniform shear flow is investigated within the framework of fluctuating hydrodynamics. It is shown that a well-known $|\
Shukla, Rajeev K.; Kumar, Atul; Srivastava, Urvashi; Srivastava, Kirti; Pandey, Vivek K.
2016-09-01
Density and acoustic velocity were measured for binary liquid mixtures of formamide, N-methylacetamide (NMA), dimethylformamide (DMF), and dimethylacetamide (DMA) with acetonitrile at atmospheric pressure and 293.15 K, 298.15 K, 303.15 K, 308.15 K, or 313.15 K over the concentration range 0.12 to 0.97. Models assuming association and nonassociation of the components of the mixtures were used to predict the behavior of the studied liquids, which would typically show weak interactions. The measured properties were fitted to the Redlich-Kister polynomial to estimate the binary coefficients and standard errors. The data were used to study the molecular interactions in the binary mixtures. Furthermore, the McAllister multibody interaction model was used to correlate the properties of the binary liquid mixtures. Testing of the nonassociation and association models for the different systems showed that, compared with the nonassociation model theoretical results, the association model theoretical results were more consistent with the experimental results.
Low Mach Number Fluctuating Hydrodynamics of Multispecies Liquid Mixtures
Donev, A; Bhattacharjee, A K; Garcia, A L; Bell, J B
2014-01-01
We develop a low Mach number formulation of the hydrodynamic equations describing transport of mass and momentum in a multispecies mixture of incompressible miscible liquids at specified temperature and pressure that generalizes our prior work on ideal mixtures of ideal gases and binary liquid mixtures. In this formulation we combine and extend a number of existing descriptions of multispecies transport available in the literature. The formulation applies to non-ideal mixtures of arbitrary number of species, without the need to single out a 'solvent' species, and includes contributions to the diffusive mass flux due to gradients of composition, temperature and pressure. Momentum transport and advective mass transport are handled using a low Mach number approach that eliminates fast sound waves (pressure fluctuations) from the full compressible system of equations and leads to a quasi-incompressible formulation. Thermal fluctuations are included in our fluctuating hydrodynamics description following the princi...
Foaming binary solution mixtures of low molecular surfactant and polyelectrolyte
Aidarova, S. B.; Musabekov, K. B.; Ospanova, Z. B.; Güden, Mustafa
2006-01-01
The lifetime of water solution foams of sodium dodecylsulfate (DDS, low molecular weight surfactant) and sodium carboxymethylcellulose (SCMC, polyelectrolyte) and their binary mixtures was experimentally investigated. The effects of ionic strength and acidity on the foam life were also determined. In binary solutions, a synergic effect of DDS and SCMC on the surface tension reduction, most likely resulting from the interaction of the surfactant with polymer, was found. The addition of NaCl in...
ZAOUI-DJELLOUL, Manel; NGADI, Amina; Mokbel, Ilham; Jose, Jaque; NGADI, Latifa
2013-01-01
Petroleum is the main energy source utilized in the world, but is availability is limited and the searche for new renewable energy sources is of major interest Vapor-liquid equilibrium (VLE) data are essential for the design of separation processes and equipment as well as for the extension of thermodynamic models Vapor-liquid equilibrium (VLE) data are essential for the design of separation processes and equipment as well as for the extension of thermodynamic models
Nockemann, Peter; Binnemans, Koen; Thijs, Ben; Parac-Vogt, Tatjana; Merz, Klaus; Mudring, Anja-Verena; Menon, Preethy Chirukandath; Rajesh, Ravindran Nair; George, Cordoyiannis; Thoen, Jan; Leys, Jan; Glorieux, Christ
2009-01-01
The ionic liquid (2-hydroxyethylammonium)trimethylammonium) bis(trifluoromethylsulfonyl)imide (choline bistriflimide) was obtained as a supercooled liquid at room temperature (melting point = 30 °C). Crystals of choline bistriflimide suitable for structure determination were grown from the melt in situ on the X-ray diffractometer. The choline cation adopts a folded conformation, whereas the bistriflimide anion exhibits a transoid conformation. The choline cation and the bistriflimide anion ar...
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...... for the two species, become active by an external driving of a transition between the two impurity states, leading to an energy flow from the impurities into the binary mixture. In steady state, the drive is found to break down the phase-separated state and lead to a new finite length scale controlled...
Ultrasonic velocity and isentropic compressibility of binary fluid mixtures at 298.15 K
Directory of Open Access Journals (Sweden)
Rajeev Kumar Shukla
2011-05-01
Full Text Available Speed of sound and isentropic compressibility of six polar-nonpolar cyclic liquid binary mixtures has been computed over the whole composition range at 298.15 K with the help of Prigogine-Flory-Patterson theory. Experimental surface tension and experimental density data were utilized in the prediction of sound velocity with the use of Auerbach relation. A comparison has then been carried out as regards the merit and demerits of the employed relations. An attempt has also been made to study the nature and magnitude of molecular interactions involved in the liquid mixture.
Isomorphic Viscosity Equation of State for Binary Fluid Mixtures.
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. PMID:26680701
International Nuclear Information System (INIS)
Measurements of osmotic coefficients of BmimCl (1-butyl-3-methylimidazolium chloride) and HmimCl (1-hexyl-3-methylimidazolium chloride) with ethanol and EmimEtSO4 (1-ethyl-3-methylimidazolium ethylsulfate) and EmpyEtSO4 (1-ethyl-3-methylpyridinium ethylsulfate) with water at T = (313.15 and 333.15) K are reported in this work. Vapour pressure and activity results of the studied binary systems are obtained from experimental measurements. The results for the osmotic coefficients are correlated using the extended Pitzer model modified by Archer and the modified NRTL (MNRTL) model. The standard deviations obtained with both models are also given. The parameters obtained with the extended Pitzer model of Archer are used to calculate the mean molal activity coefficients
Czech Academy of Sciences Publication Activity Database
Kárászová, Magda; Sedláková, Zuzana; Friess, K.; Izák, Pavel
2015-01-01
Roč. 153, OCT 16 (2015), s. 14-18. ISSN 1383-5866 R&D Projects: GA ČR GA14-12695S; GA MŠk LH14006 Institutional support: RVO:67985858 Keywords : supported ionic liquid membrane * biogas upgrading * real biogas Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.091, year: 2014
International Nuclear Information System (INIS)
Highlights: • A high-pressure view cell was used to measure the critical properties of mixtures. • Three binary mixtures’ and three ternary mixtures’ critical properties were reported. • The experimental data of each system covered the whole mole fraction range. • The critical properties of the ternary mixtures were predicted with the PR–WS model. • Empirical equations were used to correlate the experimental results. - Abstract: The critical properties of three binary mixtures and three ternary mixtures containing gasoline additives (including methanol + 1-propanol, heptane + ethanol, heptane + 1-propanol, methanol + 1-propanol + heptane, methanol + 1-propanol + methyl tert-butyl ether (MTBE), and ethanol + heptane + MTBE) were determined by a high-pressure cell. All the critical lines of binary mixtures belong to the type I described by Scott and van Konynenburg. The system of methanol + 1-propanol showed little non-ideal behavior due to their similar molecular structures. The heptane + ethanol and heptane + 1-propanol systems showed visible non-ideal behavior for their great differences in molecular structure. The Peng–Robinson equation of state combined with the Wong–Sandler mixing rule (PR–WS) was applied to correlate the critical properties of binary mixtures. The critical points of the three ternary mixtures were predicted by the PR–WS model with the binary interaction parameters using the procedure proposed by Heidemann and Khalil. The predicted critical temperatures were in good agreement with the experimental values, while the predicted critical pressures differed from the measured values. The experimental values of binary mixtures were fitted well with the Redlich–Kister equation. The critical properties of ternary mixtures were correlated with the Cibulka’s equation, and the critical surfaces were plotted using the Cibulka’s equations
El-Bagary, Ramzia I.; Elkady, Ehab F.; Ayoub, Bassam M.
2013-01-01
Simple, accurate and precise Zero order, first derivative spectrophotometric and chromatographic methods have been developed and validated for the determination of linagliptin (LNG) and metformin HCl (MET). The zero order and first derivative spectrophotometric methods were used for the determination of LNG in the range of 5-30 μg mL−1 by measuring the absorbance at 299 nm and 311 respectively. Besides, a reversed-phase liquid chromatographic (RP-LC) method is described for the simultaneous d...
Damstrup, Marianne L; Abildskov, Jens; Kiil, Søren; Jensen, Anker D; Sparsø, Flemming V; Xu, Xuebing
2006-09-20
This study was aimed at evaluating different binary solvent mixtures for efficient industrial monoacylglycerol (MAG) production by enzymatic glycerolysis. Of all investigated cases, the binary mixture of tert-butanol:tert-pentanol (TB:TP) 80:20 vol % was the most suitable organic medium for continuous enzymatic glycerolysis, ensuring high MAG formation in a short time, reasonable solvent price, and easy handling during distillation/condensation processing. A minimum solvent dosage of 44-54 wt % of the reaction mixture was necessary to achieve high MAG yields of 47-56 wt %, within 20 min. The melting and boiling points of the TB:TP mixture were estimated to be 7 and 85 degrees C, respectively, using thermodynamic models. These predictions were in good agreement with experimentally determined values. In spite of the high reaction efficiency in the binary TB:TP system, the mixture of glycerol and sunflower oil (containing 97.1% triacylglycerol) yielded surprisingly a liquid/liquid phase split behavior even at high temperatures (>80 degrees C). This in contrast to thermodynamic model calculations suggested full miscibility in all proportions. These findings suggest that enhanced reaction efficiency in organic solvent also depends upon aspects other than the system homogeneity such as reduced viscosity, reduced mass transfer limitations, and the accessibility of the substrate to the active site of the enzyme. PMID:16968070
Transport benchmarks for one-dimensional binary Markovian mixtures revisited
International Nuclear Information System (INIS)
The classic benchmarks for transport through a binary Markovian mixture are revisited to look at the probability distribution function of the chosen 'results': reflection, transmission and scalar flux. We argue that the knowledge of the ensemble averaged results is not sufficient for reliable predictions: a measure of the dispersion must also be obtained. An algorithm to estimate this dispersion is tested. (author)
Surface-Directed Spinodal Decomposition in Binary Fluid Mixtures
Bastea, Sorin; Puri, Sanjay; Lebowitz, Joel L.
2000-01-01
We consider the phase separation of binary fluids in contact with a surface which is preferentially wetted by one of the components of the mixture. We review the results available for this problem and present new numerical results obtained using a mesoscopic-level simulation technique for the 3-dimensional problem.
Linear and electronic transport in strongly coupled binary ionic mixtures
International Nuclear Information System (INIS)
A systematic investigation of linear transport properties in strongly coupled binary ionic mixtures of pointlike ions interacting solely through Coulomb interactions is presented. The basic formalism rests upon suitable extensions of the Boltzmann-Ziman equation explained in this work. Validity conditions for the Lorentzian approximation are thoroughly discussed as well as entropy arguments. High temperature inelastic contributions are emphasized out. (author)
Binary Solid-Liquid Phase Equilibria
Ellison, Herbert R.
1978-01-01
Indicates some of the information that may be obtained from a binary solid-liquid phase equilibria experiment and a method to write a computer program that will plot an ideal phase diagram to which the experimental results may be compared. (Author/CP)
Microscopic study and modeling of thermodiffusion in binary associating mixtures.
Eslamian, Morteza; Saghir, M Ziad
2009-12-01
Thermodiffusion in associating mixtures is a complex phenomenon, owing to the strong dependence of the molecular structure of such mixtures on concentration. In this paper, we attempt to elucidate this phenomenon and propose a qualitative mechanism for the separation of species in binary associating mixtures. A correlation between the sign change in the thermal diffusion factor and a change in the molecular structure, mixture viscosity, and the excess entropy of mixing in such mixtures is established. To quantify this correlation, we modify our recently developed dynamic model based on the Drickamer nonequilibrium thermodynamic approach [M. Eslamian and M. Z. Saghir, Phys. Rev. E 80, 011201 (2009)] and propose expressions for the estimation of thermal diffusion factor in binary associating mixtures. The prediction power of the proposed expressions, as well as other widely used models, are examined against the experimental data. The proposed theoretical expressions are self-contained and only rely on the viscosity data as input and predict a sign change in the thermal diffusion factor in associating mixtures. PMID:20365155
Low Mach number fluctuating hydrodynamics of multispecies liquid mixtures
Energy Technology Data Exchange (ETDEWEB)
Donev, Aleksandar, E-mail: donev@courant.nyu.edu; Bhattacharjee, Amit Kumar [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States); Nonaka, Andy; Bell, John B. [Center for Computational Science and Engineering, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Garcia, Alejandro L. [Department of Physics and Astronomy, San Jose State University, San Jose, California 95192 (United States)
2015-03-15
We develop a low Mach number formulation of the hydrodynamic equations describing transport of mass and momentum in a multispecies mixture of incompressible miscible liquids at specified temperature and pressure, which generalizes our prior work on ideal mixtures of ideal gases [Balakrishnan et al., “Fluctuating hydrodynamics of multispecies nonreactive mixtures,” Phys. Rev. E 89 013017 (2014)] and binary liquid mixtures [Donev et al., “Low mach number fluctuating hydrodynamics of diffusively mixing fluids,” Commun. Appl. Math. Comput. Sci. 9(1), 47-105 (2014)]. In this formulation, we combine and extend a number of existing descriptions of multispecies transport available in the literature. The formulation applies to non-ideal mixtures of arbitrary number of species, without the need to single out a “solvent” species, and includes contributions to the diffusive mass flux due to gradients of composition, temperature, and pressure. Momentum transport and advective mass transport are handled using a low Mach number approach that eliminates fast sound waves (pressure fluctuations) from the full compressible system of equations and leads to a quasi-incompressible formulation. Thermal fluctuations are included in our fluctuating hydrodynamics description following the principles of nonequilibrium thermodynamics. We extend the semi-implicit staggered-grid finite-volume numerical method developed in our prior work on binary liquid mixtures [Nonaka et al., “Low mach number fluctuating hydrodynamics of binary liquid mixtures,” http://arxiv.org/abs/1410.2300 (2015)] and use it to study the development of giant nonequilibrium concentration fluctuations in a ternary mixture subjected to a steady concentration gradient. We also numerically study the development of diffusion-driven gravitational instabilities in a ternary mixture and compare our numerical results to recent experimental measurements [Carballido-Landeira et al., “Mixed-mode instability of a
International Nuclear Information System (INIS)
Highlights: • Measuring and correlation of the solubility of CO2/H2S single gases in sulfolane. • Measuring the density and viscosity of (CO2/H2S + sulfolane) binary mixtures. • Correlation of density and viscosity data by the Setchenow equation. • Evaluation of Henry’s constants for solubility of CO2/H2S in sulfolane. • Evaluation of partial molar volume at infinite dilution for CO2/H2S in sulfolane. - Abstract: The density and viscosity of liquid sulfolane saturated (loaded) with single CO2 and H2S gases were measured simultaneously with the solubility of the single CO2 and H2S gases in sulfolane at temperatures ranging from (303.15 to 363.15) K and pressures of up to about 2.4 MPa using a new experimental set-up developed in our laboratory. The experimental density and viscosity values were correlated using a modified Setchenow-type equation. It was observed that the density and viscosity of mixtures decrease by increasing temperature and acid gas solubility (loading) in sulfolane. Acid gas loading has a much profounder effect on the viscosity of solutions than on their density, i.e. at a concentration of 1 mol CO2/H2S per kg of sulfolane the density decreases by less than 3%, but viscosity decreases by more than 30%. Results show that at fixed temperature and pressure H2S is more than four times as soluble as CO2 in sulfolane. The measured solubility and density values were respectively used to obtain Henry’s law constants and partial molar volumes at infinite dilution for dissolution of CO2 and H2S gases in the liquid sulfolane at the temperatures studied. The Henry’s law constants obtained at different temperatures were used to determine infinite dilution partial molar thermodynamic functions (Gibbs free energy, enthalpy and entropy) of solution. The measured solubility data were correlated by using a model comprised of the extended Henry’s law and the Pitzer’s virial expansion for the excess Gibbs free energy
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.
Wu, Tzi-Yi; Chen, Bor-Kuan; Hao, Lin; Lin, Yuan-Chung; Wang, H Paul; Kuo, Chung-Wen; Sun, I-Wen
2011-01-01
This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL) [QuatGly-OEt][EtOSO(3)] 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][EtOSO(3)] with poly(ethylene glycol) (PEG) [M(w) = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO(3)] 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 (V(m) (E) ) and deviations (Δη, Δ(x)n, Δ(Ψ)n, Δ(x)R, and Δ(Ψ)R) are discussed in terms of molecular interactions and molecular structures in the binary mixture. PMID:22272102
Solubility of anthracene in binary alcohol + 2-methoxyethanol solvent mixtures
Energy Technology Data Exchange (ETDEWEB)
McHale, M.E.R.; Powell, J.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1996-01-01
Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing 2-methoxyethanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-octanol, 2-methyl-1-propanol, and 3-methyl-1-butanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined Nearly Ideal Binary Solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.
Institute of Scientific and Technical Information of China (English)
高文颖; 陈琳; 吴富根; 尉志武
2008-01-01
The effect of cholesterol,desmosterol,stigrnasterol,sitosterol,ergosterol,and androsterol on the phase behavior of aqueous dispersions of dipalmitoylphosphatidylcholine(DPPC) was studied to understand the role of the side chain in the formation of ordered phases of the type observed in membrane rafts.Thermotropic changes in the structure of mixed dispersions and transition enthalpies were examined by synchrotron X-ray diffraction(XRD) and differential scanning calorimetry(DSC).The observations indicated that cholesterol was more efficient than phytosterols (stigmasterol and sitosterol)or ergosterol in its interaction with DPPC to form the liquid ordered phase(Lo).The Loreduced by cholesterol or desmosterol was stable over a wide temperature range,whereas,the liquid ordered phase contaimng phytostemls or ergosterol was profoundly dependent on temperature,which should be distinguished as Loβ and Loα,representing the phases below and above the main transition temperature.The characteristies in forming ordered structures of cholesterol and other sterols imply that the evolution may have selected cholesterol as the most efficient sterol for animals to form rafts in their cell membranes.%应用同步辐射X射线衍射和差示扫描量热法研究了由不同结构的固醇(胆同醇、脱氖胆固醇、豆同醇、谷固醇、麦角同醇以及固醇核)和二棕榈酰磷脂酰胆碱(DPPC)二元体系形成的液态有序相.研究表明,胆固醇比植物同醇(豆固醇和谷同醇)和真菌固醇(麦角固醇)能更有效地与DPPC形成液态有序相(Lo);有胆同醇或者脱氢胆固醇参与的液态有序相能够在较宽的温度范围内保持稳定,而由植物固醇和真菌同醇参与的液态有序相对温度有较强的依赖性,在DPPC主相变温度附近有明显的热致相变过程,因此这一液态有序相应该进一步区分为Loβ和Loα相.研究结果有助于阐明同醇尾链在液态有序相以及脂筏中的作用,也有助于理
Thermophysical properties of binary mixtures of N,N-dimethylformamide with three cyclic ethers
Directory of Open Access Journals (Sweden)
Sinha Biswajit
2013-01-01
Full Text Available Densities and viscosities of the binary mixtures consisting of tetrahydrofuran (THF, 1,3-dioxolane (1,3-DO and 1,4-dioxane (1,4-DO with N,N-dimethylformamide (DMF over the entire range of composition were measured at temperatures 298.15, 308.15 and 318.15 K and at atmospheric pressure. Ultrasonic speeds of sound of these binary mixtures were measured at ambient temperature and atmospheric pressure (T = 298.15 K and P = 1.01×105 Pa. The various experimental data were utilized to derive excess molar volumes (VmE, excess viscosities (ηE, and excess isentropic compressibilities (κsE. Using the excess molar volumes (VmE, excess partial molar volumes (and and excess partial molar volumes at infinite dilution (and of each liquid component in the mixtures were derived and discussed. Excess molar volumes (VmE as a function of composition at ambient temperature and atmospheric pressure were used further to test the applicability of the Prigogine-Flory-Patterson (PFP theory to the experimental binaries. The excess properties were found to be either negative or positive depending on the nature of molecular interactions and structural effects of liquid mixtures. Em,1V Em,2VE0,m,1VE0,m,2V.
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.
Modeling diffusion coefficients in binary mixtures of polar and non-polar compounds
DEFF Research Database (Denmark)
Medvedev, Oleg; Shapiro, Alexander
2005-01-01
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...... 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...
Positronium in solid phases of n-alkane binary mixtures
International Nuclear Information System (INIS)
Highlights: • Rotator phase in even alkanes CnH2n+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 CnH2n+2 and Cn+2H2n+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
Segregation in Vertically Vibrated Binary Granular Mixtures with Same Size
Institute of Scientific and Technical Information of China (English)
SHI Qing-Fan; SUN Gang; HOU Mei-Ying; LU Kun-Quan
2006-01-01
@@ Segregation in vertically vibrated binary granular mixtures with same size is studied experimentally. A new partial segregated state is found in this system. This state exists between the completely mixed state and the pure segregated state, and has the characteristic that the lighter particles tend to rise and form a pure layer on the top of the system while the heavier particles and some of the lighter ones stay at the bottom and form a mixed layer.
Shear viscosity for a moderately dense granular binary mixture
Garzo, Vicente; Montanero, Jose Maria
2003-01-01
The shear viscosity for a moderately dense granular binary mixture of smooth hard spheres undergoing uniform shear flow is determined. The basis for the analysis is the Enskog kinetic equation, solved first analytically by the Chapman-Enskog method up to first order in the shear rate for unforced systems as well as for systems driven by a Gaussian thermostat. As in the elastic case, practical evaluation requires a Sonine polynomial approximation. In the leading order, we determine the shear v...
Hydrodynamic limit Of a binary mixture Of rigid spheres
CHOE, HI JUN; Zhou, Shulin
2015-01-01
In this paper, we study the hydrodynamic limit of a binary mixture of rigid spheres. When Knudsen numbers of two different species are equal and go to zero, we show formally that the hydrodynamic variables satisfy the compressible Euler and Navier-Stokes equations. Like single species gas, we develop Enskog-Chapman theory up to the second order. It turns out that the macro velocities corresponding to the different spheres are equal and the ratio of the temperatures is the...
Viscosity and mutual diffusion in strongly asymmetric binary ionic mixtures
Bastea, Sorin
2006-01-01
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.
A Lattice Boltzmann model for diffusion of binary gas mixtures
Bennett, Sam
2010-01-01
This thesis describes the development of a Lattice Boltzmann (LB) model for a binary gas mixture. Specifically, channel flow driven by a density gradient with diffusion slip occurring at the wall is studied in depth. The first part of this thesis sets the foundation for the multi-component model used in the subsequent chapters. Commonly used single component LB methods use a non-physical equation of state, in which the relationship between pressure and density varies according to the sca...
Viscosity and mutual diffusion in strongly asymmetric binary ionic mixtures
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.
Simultaneous determination of ezitimibe and simvastatine in a binary mixture
International Nuclear Information System (INIS)
Complete text of publication follows. In this work is concerned with the simultaneous determination of ezitimibe and simvastatine in a binary mixture by using different methods. The first one is a derivative spectrophotometric procedure and the second one is ratio spectra first derivative spectrophotometry . In the first method, first derivative spectrophotometry, ezitimibe or simvastatine by using measurement of their first derivative signals at 237.361 nm, or 233.244 nm, respectively. The Calibration graphs were linear over the range for 4.0-28.0 μl-1 ezitimibe, or 4.0-36.0 μl-1 simvastatine. Other method, ratio spectra first derivative spectrophotometry, is based on ratio first derivative spectrophotometry, the amplitudes in the first derivative of the ratio spectra at 235.83 and at 249.51 nm were selected to determine ezitimibe and simvastatine in the binary mixture. Calibration graphs were established for 6.0-26.0 μl-1 ; linear correlation coefficient 0.9993 for ezitimibe and 3.0 - 24.6 μl-1 ; linear correlation coefficient 0.9991 for simvastatine in a binary mixture. The results obtained from first derivative spectrophotometric method were comparable with those obtained by using ratio spectra first derivative spectrophotometry. It was concluded that both the developed methods are equally accurate, sensitive, precise, reproducible, robust and rugged and the proposed methods were successfully applied to the pharmaceutical dosage from containing the above-mentioned drug combination without any interference by the excipients.
Effects of lubricants on binary direct compression mixtures.
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. PMID:22491169
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.
International Nuclear Information System (INIS)
Highlights: • Surface tensions of a pyridinium ionic liquid with an alkanol have been determined. • From experimental data surface tension deviations have been obtained and correlated. • Relative adsorptions of alkanol at the (air + liquid) interface were also calculated. • The relative adsorptions were found positive in all the mixtures. - Abstract: Surface tension for seven binary mixtures containing a pyridinium-based ionic liquid (1-propylpyridinium tetrafluoroborate, 1-butylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium tetrafluoroborate, or 1-butyl-4-methylpyridinium) and a short chain alkanol (methanol or ethanol) were determined at the temperatures: (293.15, 303.15, 313.15, and 323.15) K. From these data, the surface tension deviations were calculated. These deviations were correlated using a Redlich–Kister polynomial expansion. Moreover, relative adsorptions of alkanol at the (air + liquid) interface were calculated from the Gibbs isotherm
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. PMID:26886302
Viscosity mixing rules for binary systems containing one ionic liquid.
Tariq, Mohammed; Altamash, Tausif; Salavera, Daniel; Coronas, Alberto; Rebelo, Luis P N; Canongia Lopes, Jose N
2013-06-24
In this work the applicability of four of the most commonly used viscosity mixing rules to [ionic liquid (IL)+molecular solvent (MS)] systems is assessed. More than one hundred (IL+MS) binary mixtures were selected from the literature to test the viscosity mixing rules proposed by 1) Hind (Hi), 2) Grunberg and Nissan (G-N), 3) Herric (He) and 4) Katti and Chaudhri (K-C). The analyses were performed by estimating the average (absolute or relative) deviations, AADs and ARDs, between the available experimental data and the predicted ideal mixture viscosity values obtained by means of each rule. The interaction terms corresponding to the adjustable parameters inherent to each rule were also calculated and their trends discussed. PMID:23650138
International Nuclear Information System (INIS)
In work on the basis of a method of the kinetic equations it is output the differential equations for binary density and a binary stream of particles of electro conducting magnetic liquids. These equations are the nonuniform equations of parabolic type. The solution of these equations completely feature existential behaviour of binary density and a binary stream of particles of electro conducting magnetic liquids, i.e. process of a structural relaxation. (author)
Flow regime and deposition pattern of evaporating binary mixture droplet suspended with particles.
Zhong, Xin; Duan, Fei
2016-02-01
The flow regimes and the deposition pattern have been investigated by changing the ethanol concentration in a water-based binary mixture droplet suspended with alumina nanoparticles. To visualize the flow patterns, Particle Image Velocimetry (PIV) has been applied in the binary liquid droplet containing the fluorescent microspheres. Three distinct flow regimes have been revealed in the evaporation. In Regime I, the vortices and chaotic flows are found to carry the particles to the liquid-vapor interface and to promote the formation of particle aggregation. The aggregates move inwards in Regime II as induced by the Marangoni flow along the droplet free surface. Regime III is dominated by the drying of the left water and the capillary flow driving particles radially outward is observed. The relative weightings of Regimes I and II, which are enhanced with an increasing load of ethanol, determine the motion of the nanoparticles and the formation of the final drying pattern. PMID:26920521
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.
Solubilities of benzoic acid in binary (benzyl alcohol + benzaldehyde) solvent mixtures
International Nuclear Information System (INIS)
Highlights: • Solubilities of benzoic acid in (benzyl alcohol + benzaldehyde) mixtures were measured at 1 atm. • The experimental temperature ranges at (298.35 to 355.65) K. • Effects of benzyl alcohol mass concentration at (0.00 to 1.00) on the solubilities of benzoic acid were studied. • The experimental data were correlated with NRTL model. • Thermodynamic functions of dissolution of benzoic acid in (benzyl alcohol + benzaldehyde) mixtures were discussed. - Abstract: The solubility of benzoic acid in binary (benzyl alcohol + benzaldehyde) solvent mixtures was measured at temperature from (298.35 to 355.65) K and atmospheric pressure. The measured solubility increases with the increasing temperature at constant solvent composition. The effects of mass fraction benzaldehyde in the solvent mixtures at (0.0 to 1.00) on the solubility were studied. The measured solubility decreases with the increasing mass fraction of benzaldehyde. The experimental results were correlated with the non-random two-liquid (NRTL) equations, and good agreement between the correlated and the experimental values was obtained. Thermodynamic functions for the solution of benzoic acid in binary (benzyl alcohol + benzaldehyde) solvent mixtures were calculated with the van’t Hoff plot. The apparent dissolution Gibbs free energy change was also calculated
Coexisting Pulses in a Model for Binary-Mixture Convection
Riecke, H; Riecke, Hermann; Rappel, Wouter-Jan
1995-01-01
We address the striking coexistence of localized waves (`pulses') of different lengths which was observed in recent experiments and full numerical simulations of binary-mixture convection. Using a set of extended Ginzburg-Landau equations, we show that this multiplicity finds a natural explanation in terms of the competition of two distinct, physical localization mechanisms; one arises from dispersion and the other from a concentration mode. This competition is absent in the standard Ginzburg-Landau equation. It may also be relevant in other waves coupled to a large-scale field.
Mixing properties of binary mixtures presenting azeotropes at several temperatures
International Nuclear Information System (INIS)
Experimental densities, speeds of sound, and refractive indices of the binary mixtures presenting azeotropes of (ethanol with hexane or heptane or 2-butanone) and (2-propanol with 2-butanone or ethylacetate or cyclohexane) were determined from T = (293.15 to 303.15) K. Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems were calculated. A function of the mole fraction and temperature polynomial equation was used to fit these quantities. The standard deviations between experimental and calculated values are shown
Structure and rheology of binary mixtures in shear flow
Corberi, F.; Gonnella, G.; Lamura, A.
2000-01-01
Results are presented for the phase separation process of a binary mixture subject to an uniform shear flow quenched from a disordered to a homogeneous ordered phase. The kinetics of the process is described in the context of the time-dependent Ginzburg-Landau equation with an external velocity term. The large-N approximation is used to study the evolution of the model in the presence of a stationary flow and in the case of an oscillating shear. For stationary flow we show that the structure ...
STUDY OF MOLECULAR INTERACTIONS IN BINARY MIXTURES USING EXCESS PARAMETERS
Narendra Kolla
2014-01-01
Speeds of sound, densities and viscosities of the binary mixture of anisaldehyde with nonanol were measured over the entire mole fraction at (303.15, 308.15, 313.15 and 318.15) K E E and normal atmospheric pressure. Excess molar volume, V , Excess internal pressure, π , m E *E excess enthalpy, H , excess Gibb's free energy of activation for viscous flow, G , and excess E E viscosity,η have been calculated using experimental data. The V values are positive whereas m ...
Asymptotic-preserving Boltzmann model equations for binary gas mixture
Liu, Sha; Liang, Yihua
2016-02-01
An improved system of Boltzmann model equations is developed for binary gas mixture. This system of model equations has a complete asymptotic preserving property that can strictly recover the Navier-Stokes equations in the continuum limit with the correct constitutive relations and the correct viscosity, thermal conduction, diffusion, and thermal diffusion coefficients. In this equation system, the self- and cross-collision terms in Boltzmann equations are replaced by single relaxation terms. In monocomponent case, this system of equations can be reduced to the commonly used Shakhov equation. The conservation property and the H theorem which are important for model equations are also satisfied by this system of model equations.
Viscosity and phase separations of binary CO-He and CO-Ar mixtures
Rademacher, N.; Bayarjargal, L.; Morgenroth, W.; Ciezak-Jenkins, J. A.; Winkler, B.
2015-01-01
Binary mixtures of 10 and 25 vol% CO in He and 10 vol% CO in Ar have been studied at high pressures and ambient temperature in diamond anvil cells. Phase separations were observed at 5.7(3) GPa, 3.6(2) GPa and 1.6(1) GPa. Earlier studies of ?-He mixtures of comparable concentrations revealed phase separations at significantly larger pressures, while ?-Ar mixtures separate at pressures comparable to those observed in the CO-Ar system here. The viscosity of a CO-rich fluid phase was determined by measuring the velocities of rising He bubbles. After corrections for the influence of the finite container size and of remaining helium in CO, the viscosity of the CO-rich fluid at 3.8(1) GPa was ≈3(1) mPa s, similar to what would be expected for isoelectronic liquid ? under the same conditions.
Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT
DEFF Research Database (Denmark)
Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios
2004-01-01
Two algorithms for evaluating liquid-liquid equilibria (LLE) for binary and ternary polymer solutions are presented. The binary algorithm provides the temperature versus concentration cloud-point curve at fixed pressure, whereas the ternary algorithm provides component 1 versus component 2...... accuracy, even by using interaction parameters obtained from binary vapor-liquid equlibrium data....
Induced smectic phases of stoichiometric liquid crystal mixtures.
Sugisawa, Shin-Ya; Tabe, Yuka
2016-03-16
We revealed the detailed structures of induced smectic liquid crystal (LC) phases composed of a binary mixture of charge-transfer (CT) LC substances. Although neither of the constituents had highly ordered smectic phases, the mixture exhibited smectic-E (SmE) or smectic-B (SmB) phases when mixed at ratios of 1 : 1 and 2 : 3, respectively. The results of polarized optical microscopy, differential scanning calorimetry, X-ray diffraction, and infrared spectroscopy indicated that the induced smectic phases were stabilized by an exquisite balance between the CT interactions, dipolar interactions, and excluded volume effects. We proposed a possible model for the molecular arrangements in the SmE and SmB phases, which consistently explained the experimental results including the stoichiometric ratios. PMID:26898174
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.
Micro-visualization of fluidizing behavior of binary particle mixtures
International Nuclear Information System (INIS)
The quality of fluidization affects directly heat transfer characteristics. Previous studies at this Institute demonstrated that a coarse Geldart Group-B powder and a fine Geldart Group-C powder could improve the otherwise poor fluidizing quality of either component, when mixed together in appropriate proportions. To elucidate the above synergistic action, the authors' investigation is designed to visualize, by video recording under a microscope, the dynamic behavior of binary mixtures on a particle-size scale within a field of vision of the order of a few millimeters. Two types of experiments were conducted: fluidization of the binary mixtures with different weight fractions of the components; and flooding a single sessile coarse particle with a flowing dilute suspension of fine particles at different gas velocities. Based on balance of forces on a fine particle at the surface of a coarse, for the actions of gravity, adhesion and hydrodynamics due to the adjacent flowing gas stream, a mathematical model was formulated to account for the shifting region of fine-particle coverage on the coarse
Chung-Wen Kuo; I-Wen Sun; Yuan-Chung Lin; H. Paul Wang; Bor-Kuan Chen; Lin Hao; Tzi-Yi Wu
2011-01-01
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...
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...
Ionic-Liquid Based Separation of Azeotropic Mixtures
DEFF Research Database (Denmark)
Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul
2014-01-01
methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria 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...... 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....
Phase equilibria of binary mixtures by molecular simulation and cubic equations of state
Directory of Open Access Journals (Sweden)
V.F. Cabral
2001-06-01
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.
The potential energy landscape in the Lennard-Jones binary mixture model
International Nuclear Information System (INIS)
The potential energy landscape in the Kob-Andersen Lennard-Jones binary mixture model has been studied carefully from the liquid down to the supercooled regime, from T = 2 down to 0.46. One thousand independent configurations along the time evolution locus have been examined at each temperature investigated. From the starting configuration, we searched for the nearest saddle (or quasi-saddle) and minimum of the potential energy. The vibrational densities of states for the starting and the two derived configurations have been evaluated. Besides the number of negative eigenvalues of the saddles other quantities show some signature of the approach of the dynamical arrest temperature
Henry's law, surface tension, and surface adsorption in dilute binary mixtures
Onuki, Akira
2009-01-01
Equilibrium properties of dilute binary fluid mixtures are studied in two-phase states on the basis of a Helmholtz free energy including the gradient free energy. The solute partitioning between gas and liquid (Henry's law) and the surface tension change $\\Delta\\gamma$ are discussed. A derivation of the Gibbs law $\\Delta\\gamma=-T\\Gamma$ is given with $\\Gamma$ being the surface adsorption. Calculated quantities include the derivatives $d T_c/dX$ and $d p_c/dX$ of the critical temperature and p...
B. Schmitt; Kiefer, C; Schütze, A.
2015-01-01
A novel sensor principle for determining binary fluid mixtures of known components is presented, making use of different thermal and rheological properties of the mixture's components. Using a microheater, a heat pulse is introduced in the mixture. The resulting temperature increase depends on the thermal properties of the mixture, allowing determination of the mixture ratio. Placing a bluff body in the fluid channel causes the formation of a stationary pair of vortices behi...
Iloukhani, H.; Khanlarzadeh, K.; Rakhshi, M.
2011-03-01
Densities, viscosities, and refractive indices of binary mixtures of n-butyl acetate (1) +1-chlorobutane (2), +1-chloropentane (2), +1-chlorohexane (2), +1-chloroheptane (2), and +1-chlorooctane (2) were measured at 298.15 K for the liquid region and at ambient pressure for the whole composition range. The excess molar volumes V E were calculated from experimental densities. McAllister's three-body interaction, and Hind and Grunberg-Nissan models are used for correlating the viscosity of binary mixtures. The experimental data of binaries are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.
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.
Quantum cluster equilibrium model of N-methylformamide-water binary mixtures.
von Domaros, Michael; Jähnigen, Sascha; Friedrich, Joachim; Kirchner, Barbara
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. PMID:26874486
Quantum cluster equilibrium model of N-methylformamide–water binary mixtures
International Nuclear Information System (INIS)
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
International Nuclear Information System (INIS)
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. • VE for benzylalcohol with studied 1-alcohols are positive while κSE 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 (VE) and compared with predictive expression proposed by Redlich–Kister equation. Excess speed of sound (uE), isentropic compressibility (κS) and excess isentropic compressibilities (κSE) 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
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.
International Nuclear Information System (INIS)
Highlights: ► We report the investigations of surface tensions of binary systems of ionic liquids with aprotic substances. ► DMSO similarly like water has higher surface tension in comparison with ionic liquids under test. ► It seems that surface activity of aprotic substance in mixture with ionic liquid is different than of alcohols. ► Real surface activity of aprotic substance in binary mixtures is always lower than the ideal one. -- Abstract: The surface tension, σ, of binary mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIm][NTf2] with tetrahydrofuran (oxolane, thf), acetonitrile, dimethylsulfoxide ((methylsufinyl)methane, dmso) and of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [EMIm][NTf2] with dimethylsufoxide was measured between (293.15 and 313.15) K using the pendant drop method. On the basis of experimental σ values and activity coefficients of solutes in their solutions with ionic liquid obtained from vapor pressure measurement, Gibbs excess surface concentrations of thf, acetonitrile or dmso in mixtures with [BMIm][NTf2] or [EMIm][NTf2] were determined. The results are discussed in terms of possible interactions between ILs and aprotic polar substances
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.
Solubility of anthracene in binary alcohol + 2-ethyl-1-hexanol solvent mixtures
Energy Technology Data Exchange (ETDEWEB)
Powell, J.R.; McHale, M.E.R.; Kauppila, A.S.M.; Otero, P.; Jayasekera, M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1995-11-01
Solid-liquid equilibrium data of organic nonelectrolyte systems are becoming increasingly important in the petroleum industry, particularly in light of present trends toward heavier feedstocks and known carcinogenicity/mutagenicity of many of the larger polycyclic aromatic compounds. Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing 2-ethyl-l-hexanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-octanol, 2-methyl-1-propanol, and 3-methyl-1-butanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values on the order of 0.6%.
A structural investigation of ionic liquid mixtures.
Matthews, Richard P; Villar-Garcia, Ignacio J; Weber, Cameron C; Griffith, Jeraime; Cameron, Fiona; Hallett, Jason P; Hunt, Patricia A; Welton, Tom
2016-03-16
The structures of mixtures of ionic liquids (ILs) featuring a common 1-butyl-3-methylimidazolium ([C4C1im](+)) cation but different anions have been investigated both experimentally and computationally. (1)H and (13)C NMR of the ILs and their mixtures has been performed both on the undiluted liquids and those diluted by CD2Cl2. These experiments have been complemented by quantum chemical density functional theory calculations and molecular dynamics simulations. These techniques have identified the formation of preferential interactions between H(2) of the imidazolium cation and the most strongly hydrogen bond (H-bond) accepting anion. In addition, a preference for the more weakly H-bond accepting anion to interact above the imidazolium ring through anion-π(+) interactions has been identified. The modelling of these data has identified that the magnitude of these preferences are small, of the order of only a few kJ mol(-1), for all IL mixtures. No clustering of the anions around a specific cation could be observed, indicating that these interactions arise from the reorientation of the cation within a randomly assigned network of anions. π(+)-π(+) stacking of the imidazolium cations was also studied and found to be promoted by ILs with a strong H-bond accepting anion. Stacking interactions are easily disrupted by the introduction of small proportions (accounting for why most IL mixtures exhibit ideal, or nearly ideal, behaviour. PMID:26947103
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.
Solubility of anthracene and pyrene in binary alcohol + alcohol solvent mixtures
Energy Technology Data Exchange (ETDEWEB)
Zvaigzne, A.I.; McHale, M.E.R.; Powell, J.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1995-11-01
Solid-liquid equilibrium data of organic nonelectrolyte systems are becoming increasingly important in the petroleum industry, particularly in light of present trends toward heavier feedstocks and known carcinogenicity/mutagenicity of many of the larger polycyclic aromatic compounds. Experimental solubilities are reported for anthracene dissolved in binary 1-octanol + 2-propanol, 2-butanol + 1-butanol, 1-octanol + 1-butanol, 3-methyl-1-butanol + 1-propanol, and 2-methyl-1-propanol + 1-butanol mixtures at 25 C, and for pyrene dissolved in binary solvent mixtures containing 2-ethyl-1-hexanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-octanol, 2-methyl-1-propanol, and 3-methyl-1-butanol at 26 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the 12 systems studied, the combined NIBS/Redlich-Kister equation was found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.4%. Slightly larger deviations were noted in the case of the modified Wilson equation.
Fujitani, Youhei
2014-08-01
We consider a spherical liquid droplet immersed in a near-critical binary fluid mixture whose components interact with the droplet slightly unequally. Assuming uniform viscosity of the mixture, we use the Gaussian free-energy functional to calculate the pressure and velocity fields occurring when a weak linear shear flow is imposed far from the droplet. These fields in the limit of infinite droplet viscosity give those for a rigid sphere. Using these fields, we calculate the effective viscosity emerging when identical droplets or rigid spheres are dilutely dispersed in the mixture.
Deuterium isotope separation from a binary mixture by distillation
International Nuclear Information System (INIS)
In this work, mathematical models for deuterium separation process from a binary mixture are presented. The models are applied to single and double stage distillation installation. The examples refer to the cryogenic distillation of hydrogen in a single stage installation and the vacuum isotope distillation of water in double stage installation. The models are presented as charts and diagrams. The presented models ensure a complete solution for simulation and design issues as their computer programing rises no difficulty. To improve the computation accuracy it is recommended to take into account the temperature variation of physical parameters of the system as well as of the dependence of packing characteristics on loading factor. This way one can compute the exact case either with α and ρ variable along the column or with their average values. (authors)
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.
Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures
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.
DEFF Research Database (Denmark)
Bjørner, Martin Gamel; Kontogeorgis, Georgios
2016-01-01
vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) of mixtures containing CO2 and hydrocarbons, water, alcohols, or selected quadrupolar compounds.The results indicate that most pure compound property predictions are satisfactory but similar to other CPA approaches. When binary mixtures...... (qCPA) can be used without introducing any additional pure compound parameters. Alternatively a single additional adjustable parameter can be employed.To evaluate qCPA several pure compound properties are predicted. The model is furthermore evaluated for its ability to predict and correlate binary...
Mutual diffusion in the ternary mixture of water + methanol + ethanol and its binary subsystems.
Parez, Stanislav; Guevara-Carrion, Gabriela; Hasse, Hans; Vrabec, Jadran
2013-03-21
Mutual diffusion is investigated by means of experiment and molecular simulation for liquid mixtures containing water + methanol + ethanol. The Fick diffusion coefficient is measured by Taylor dispersion as a function of composition for all three binary subsystems under ambient conditions. For the aqueous systems, these data compare well with literature values. In the case of methanol + ethanol, experimental measurements of the Fick diffusion coefficient are presented for the first time. The Maxwell-Stefan diffusion coefficient and the thermodynamic factor are predicted for the ternary mixture as well as its binary subsystems by molecular simulation in a consistent manner. The resulting Fick diffusion coefficient is compared to present measurements and that obtained from the classical simulation approach, which requires experimental vapor-liquid equilibrium or excess enthalpy data. Moreover, the self-diffusion coefficients and the shear viscosity are predicted by molecular dynamics and are favorably compared to experimental literature values. The presented ternary diffusion data should facilitate the development of aggregated predictive models for diffusion coefficients of polar and hydrogen-bonding systems. PMID:23400088
A Variational approach to thin film hydrodynamics of binary mixtures
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.
Calculation of the viscosity of binary liquids at various temperatures using Jouyban-Acree model.
Jouyban, Abolghasem; Khoubnasabjafari, Maryam; Vaez-Gharamaleki, Zahra; Fekari, Zohreh; Acree, William Eugene
2005-05-01
Applicability of the Jouyban-Acree model for calculating absolute viscosity of binary liquid mixtures with respect to temperature and mixture composition is proposed. The correlation ability of the model is evaluated by employing viscosity data of 143 various aqueous and non-aqueous liquid mixtures at various temperatures collected from the literature. The results show that the model is able to correlate the data with an overall percentage deviation (PD) of 1.9+/-2.5%. In order to test the prediction capability of the model, three experimental viscosities from the highest and lowest temperatures along with the viscosities of neat liquids at all temperatures have been employed to train the model, then the viscosity values at other mixture compositions and temperatures were predicted and the overall PD obtained is 2.6+/-4.0%. PMID:15863923
Critical exponent for the viscosity of four binary liquids
Berg, Robert F.; Moldover, Michael R.
1988-01-01
The viscosity of the following binary mixtures was measured near their consolute points: (1) methanol + cyclohexane, (2) isobutyric acid + water, (3) nitroethane + 3-methylpentane, and (4) 2-butoxyethanol + water. It is shown that the multiplicative hypothesis is valid for these mixtures. It is also found that the concentration closest to critical has the largest viscosity enhancement.
Krishnan, Kannan; Haddad, Sami; Béliveau, Martin; Tardif, Robert
2002-12-01
The available data on binary interactions are yet to be considered within the context of mixture risk assessment because of our inability to predict the effect of a third or a fourth chemical in the mixture on the interacting binary pairs. Physiologically based pharmacokinetic (PBPK) models represent a potentially useful framework for predicting the consequences of interactions in mixtures of increasing complexity. This article highlights the conceptual basis and validity of PBPK models for extrapolating the occurrence and magnitude of interactions from binary to more complex chemical mixtures. The methodology involves the development of PBPK models for all mixture components and interconnecting them at the level of the tissue where the interaction is occurring. Once all component models are interconnected at the binary level, the PBPK framework simulates the kinetics of all mixture components, accounting for the interactions occurring at various levels in more complex mixtures. This aspect was validated by comparing the simulations of a binary interaction-based PBPK model with experimental data on the inhalation kinetics of m-xylene, toluene, ethyl benzene, dichloromethane, and benzene in mixtures of varying composition and complexity. The ability to predict the kinetics of chemicals in complex mixtures by accounting for binary interactions alone within a PBPK model is a significant step toward the development of interaction-based risk assessment for chemical mixtures. PMID:12634130
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.
Beniwal, Vijay; Kumar, Anil
2016-08-24
Physico-chemical properties of liquid mixtures in general display large deviations from linear behaviour, arising out of complex specific and non-specific intermolecular interactions. The polarity of liquid mixtures displaying large positive and negative deviations can be minimized and linear mixing can be achieved in liquids using a pseudo-solvent methodology. The work described herein is designed to investigate the influence of different physical parameters on the linear pseudo-solvent composition in ionic liquid mixtures. For this purpose, we have determined the deviations from linearity, ΔE values (defined as given by ) for binary mixtures of a variety of ionic liquids, including two molecular solvents, DMSO and formamide. Firstly, the investigations were carried out in three 1-butyl-3-methylimidazolium cation based aprotic ionic liquids and the roles of anionic structure and hydrogen bond acceptor basicities (β values) of the ionic liquids were determined. The influence of the cationic structure, i.e., the hydrogen bond donor acidity (α values) and non-associative nature of the ionic liquids, was determined using C2-methylated analogs, 1-butyl-2,3-dimethylimidazolium cation based ionic liquids. The role of the protic nature of ionic liquids was studied in two protic ionic liquids, viz., 1-methylimidazolium formate and 1-methylimidazolium acetate. The effects of the temperature, pseudo-solvent structure and solvatochromic probe structure on the ΔE values were also explored. PMID:27523572
Non-equilibrium dynamics of glass-forming liquid mixtures
Sánchez-Díaz, Luis Enrique; Lázaro-Lázaro, Edilio; Olais-Govea, José Manuel; Medina-Noyola, Magdaleno
2014-06-01
The non-equilibrium self-consistent generalized Langevin equation theory of irreversible processes in glass-forming liquids [P. Ramírez-González and M. Medina-Noyola, Phys. Rev. E 82, 061503 (2010)] is extended here to multi-component systems. The resulting theory describes the statistical properties of the instantaneous local particle concentration profiles nα(r, t) of species α in terms of the coupled time-evolution equations for the mean value overline{n}_α ({r},t) and for the covariance σ _{α β }({r},{r}^' };t)equiv overline{δ n_α ({r},t)δ n_β ({r}^' },t)} of the fluctuations δ n_α ({r},t) = n_α ({r},t)- overline{n}_α ({r},t). As in the monocomponent case, these two coarse-grained equations involve a local mobility function bα(r, t) for each species, written in terms of the memory function of the two-time correlation function C_{α β }({r},{r}^' };t,t^' }) equiv overline{δ n_α ({r},t)δ n_β ({r}^' },t^' })}. If the system is constrained to remain spatially uniform and subjected to a non-equilibrium preparation protocol described by a given temperature and composition change program T(t) and overline{n}_α (t), these equations predict the irreversible structural relaxation of the partial static structure factors Sαβ(k; t) and of the (collective and self) intermediate scattering functions Fαβ(k, τ; t) and F^S_{α β }(k,τ ;t). We illustrate the applicability of the resulting theory with two examples involving simple model mixtures subjected to an instantaneous temperature quench: an electroneutral binary mixture of equally sized and oppositely charged hard-spheres, and a binary mixture of soft-spheres of moderate size-asymmetry.
Nature of Mesoscopic Organization in Protic Ionic Liquid-Alcohol Mixtures.
Schroer, Wolffram; Triolo, Alessandro; Russina, Olga
2016-03-10
The mesoscopic morphology of mixtures of ethylammonium nitrate, a protic ionic liquid, and n-pentanol is explored for the first time using small angle X-ray scattering as a function of concentration and temperature. Both compounds are amphiphilic and characterized by an extended hydrogen bonding network; however, though macroscopically homogeneous, their mixtures are highly heterogeneous at the mesoscopic spatial scales. Previous structural studies rationalized similar features in related mixtures proposing the existence of large aggregates or micelle- and/or microemulsion-like structures. Here we show that a detailed analysis of the present concentration and temperature resolved experimental data set supports a structural scenario where the mesoscopic heterogeneities are the due to density fluctuations that are precursors of liquid-liquid phase separation. Accordingly no existence of structurally organized aggregates (such as micellar or microemulsion aggregates) is required to account for the mesoscopic heterogeneities detected in this class of binary mixtures. PMID:26895177
Dissipation process of binary gas mixtures in thermally relativistic flow
Yano, Ryosuke
2016-04-01
In this paper, dissipation process of binary gas mixtures in thermally relativistic flows is discussed with focus on characteristics of diffusion flux. As an analytical object, we consider the relativistic rarefied-shock layer around a triangular prism. Numerical results for 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 et al (1976 Physica A 84 165–74). In the case of uniform flow with 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 a 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 similar to that of the NSF order approximation inside the shock wave, unlike the pressure deviator, dynamic pressure and heat flux, even when the Lorentz contraction in the uniform flow becomes large, because the diffusion flux does not depend on the generic Knudsen number from its definition in Eckart’s frame. Finally, the author concludes that for accuracy diffusion flux must be calculated using the particle four-flow and averaged four velocity, which are formulated using the four velocity defined by each species of hard spherical particles.
Dissipation process of binary mixture gas in thermally relativistic flow
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...
Decomposition and interface evolution in films of binary mixtures
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).
Triphilic Ionic-Liquid Mixtures: Fluorinated and Non-fluorinated Aprotic Ionic-Liquid Mixtures.
Hollóczki, Oldamur; Macchiagodena, Marina; Weber, Henry; Thomas, Martin; Brehm, Martin; Stark, Annegret; Russina, Olga; Triolo, Alessandro; Kirchner, Barbara
2015-10-26
We present here the possibility of forming triphilic mixtures from alkyl- and fluoroalkylimidazolium ionic liquids, thus, macroscopically homogeneous mixtures for which instead of the often observed two domains-polar and nonpolar-three stable microphases are present: polar, lipophilic, and fluorous ones. The fluorinated side chains of the cations indeed self-associate and form domains that are segregated from those of the polar and alkyl domains. To enable miscibility, despite the generally preferred macroscopic separation between fluorous and alkyl moieties, the importance of strong hydrogen bonding is shown. As the long-range structure in the alkyl and fluoroalkyl domains is dependent on the composition of the liquid, we propose that the heterogeneous, triphilic structure can be easily tuned by the molar ratio of the components. We believe that further development may allow the design of switchable, smart liquids that change their properties in a predictable way according to their composition or even their environment. PMID:26305804
Juhasz, Janos; Davis, James H; Sharom, Frances J
2012-01-01
The phase behavior of membrane lipids is known to influence the organization and function of many integral proteins. Giant unilamellar vesicles (GUVs) provide a very useful model system in which to examine the details of lipid phase separation using fluorescence imaging. The visualization of domains in GUVs of binary and ternary lipid mixtures requires fluorescent probes with partitioning preference for one of the phases present. To avoid possible pitfalls when interpreting the phase behavior of these lipid mixtures, sufficiently thorough characterization of the fluorescent probes used in these studies is needed. It is now evident that fluorescent probes display different partitioning preferences between lipid phases, depending on the specific lipid host system. Here, we demonstrate the benefit of using a panel of fluorescent probes and confocal fluorescence microscopy to examine phase separation in GUVs of binary mixtures of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Patch and fibril gel phase domains were found to co-exist with liquid disordered (l(d)) domains on the surface of GUVs composed of 40:60 mol% DOPC/DPPC, over a wide range of temperatures (14-25°C). The fluorescent lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl (NBD-DPPE), proved to be the most effective probe for visualization of fibril domains. In the presence of Lissamine(TM) rhodamine B 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (Rh-DPPE) we were unable to detect fibril domains. This fluorophore also affected the partitioning behavior of other fluorescent probes. Overall, we show that the selection of different fluorescent probes as lipid phase reporters can result in very different interpretation of the phase behavior of DOPC/DPPC mixtures. PMID:21945563
Leahy-Dios, Alana; Zhuo, Lin; Firoozabadi, Abbas
2008-05-22
New thermal diffusion coefficients of binary mixtures are measured for n-decane-n-alkanes and 1-methylnaphthalene-n-alkanes with 25 and 75 wt % at 25 degrees C and 1 atm using the thermogravitational column technique. The alkanes range from n-pentane to n-eicosane. The new results confirm the recently observed nonmonotonic behavior of thermal diffusion coefficients with molecular weight for binary mixtures of n-decane- n-alkanes at the compositions studied. In this work, the mobility and disparity effects on thermal diffusion coefficients are quantified for binary mixtures. We also show for the binary mixtures studied that the thermal diffusion coefficients and mixture viscosity, both nonequilibrium properties, are closely related. PMID:18438988
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.
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
Reliable correlation and prediction of liquid densities are important for designing chemical processes at normal and elevated pressures. A corresponding-states model from molecular theory was extended to yield a robust method for quality testing of experimental data that also provides predicted...... 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...
The Soret Effect in Liquid Mixtures - A Review
Köhler, Werner; Morozov, Konstantin I.
2016-07-01
The Soret effect describes diffusive motion that originates from a temperature gradient. It is observed in mixtures of gases, liquids and even solids. Although there is a formal phenomenological description based on linear nonequilibrium thermodynamics, the Soret effect is a multicause phenomenon and there is no univocal microscopic picture. After a brief historical overview and an outline of the fundamental thermodynamic concepts, this review focuses on thermodiffusion in binary and ternary liquid mixtures. The most important experimental techniques used nowadays are introduced. Then, a modern development in studying thermal diffusion, the discovery of both integral and specific additivity laws, is discussed. The former relate to the general behavior of the substances in a temperature field according to their thermophobicities, which prove to be pure component properties. The thermophobicities allow for a convenient classification of the phenomenon, a simple interpretation and a proper estimation and prediction of the thermodiffusion parameters. The specific laws relate to the additivity of the particular contributions. Among the latter, we discuss the isotopic Soret effect and the so-called chemical contribution. From the theoretical side, there are kinetic and thermodynamic theories, and the nature of the driving forces of thermodiffusion can be either of volume or surface type. Besides analytical models, computer simulations become increasingly important. Polymer solutions are special as they represent highly asymmetric molecular systems with a molar mass-independent thermophoretic mobility. Its origin is still under debate, and draining and non-draining models are presently discussed. Finally, some discussion is devoted to ternary mixtures, which only recently have been investigated in more detail.
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.
Modeling adsorption of liquid mixtures on porous materials
DEFF Research Database (Denmark)
Monsalvo, Matias Alfonso; Shapiro, Alexander
2009-01-01
of the MPTA onto liquids has been tested on experimental binary and ternary adsorption data. We show that, for the set of experimental data considered in this work, the MPTA model is capable of correlating binary adsorption equilibria. Based on binary adsorption data, the theory can then predict...... ternary adsorption equilibria. Good agreement with the theoretical predictions is achieved in most of the cases. Some limitations of the model are also discussed....
International Nuclear Information System (INIS)
Research highlights: → Excess molar volumes and excess logarithm viscosities for the binary mixtures of 1-hexyl-3-methylimidazolium tetrafluroborate were determined. → The absolute values of VmE follow the sequence: THF > butanone > ethyl acetate > butylamine for the binary systems. → The values of (lnη)E decrease in the order: THF > butylamine > ethyl acetate > butanone. → Ion-dipole interaction, the hydrogen bond, the packing efficiency and the ion-pairs exist in the ionic liquid are believed to influence the excess properties of the related systems. → The information obtained in this work allows us to show how physical properties of molecular solvents affect their interaction with the ionic liquid. - Abstract: Information on the interactions between ionic liquids and molecular solvents are essential for the understanding of the function of ionic liquids in related procedures, and excess properties are sensitive probe for these interactions. In this work, excess molar volume (VmE) and excess logarithmic viscosity ((ln η)E) for the binary mixtures of 1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4]) with butanone, ethyl acetate, butylamine, and tetrahydrofuran have been determined from density and viscosity measurements in the whole composition range at the temperature of 298.15 K. It is found that for the studied systems, the values of VmE are negative but those of (ln η)E are positive in the whole concentration range. The VmE values show their minimum at the ionic liquid mole fraction of 0.3, and (ln η)E values exhibit a maximum at the same composition. The absolute values of VmE follow the sequence: tetrahydrofuran > butanone > ethyl acetate > butylamine for the binary systems, whereas the values of (ln η)E decrease in the order: tetrahydrofuran > butylamine > ethyl acetate > butanone. The results have been analyzed through the ion-dipole interaction, the hydrogen bonding, the packing efficiency and the ion-pairs exist in the ionic
Liquid mixture convection during phase separation in a temperature gradient
Lamorgese, A. G.; Mauri, R.
2011-03-01
We simulate the phase separation of a low-viscosity binary mixture, assuming that the fluid system is confined between two walls that are cooled down to different temperatures below the critical point of the mixture, corresponding to quenches within the unstable range of its phase diagram. Spinodal decomposition patterns for off-critical mixtures are studied numerically in two dimensions in the creeping flow limit and for a large Lewis number, together with their dependence on the fluidity coefficient. Our numerical results reproduce the large-scale unidirectional migration of phase-separating droplets that was observed experimentally by Califano et al. ["Large-scale, unidirectional convection during phase separation of a density-matched liquid mixture," Phys. Fluids 17, 094109 (2005)], who measured typical speeds that are quite larger than the Marangoni velocity. To understand this finding, we then studied the temperature-gradient-induced motion of an isolated droplet of the minority phase embedded in a continuous phase, showing that when the drop is near local equilibrium, its speed is of the same order as the Marangoni velocity, i.e., it is proportional to the unperturbed temperature gradient and the fluidity coefficient. However, far from local equilibrium, i.e., for very large unperturbed temperature gradients, the drop first accelerates to a speed that is larger than the Marangoni velocity, then, later, it decelerates, exhibiting an increase-decrease behavior, as described by Yin et al. ["Thermocapillary migration of nondeformable drops," Phys. Fluids 20, 082101 (2008)]. Such behavior is due to the large nonequilibrium, Korteweg-driven convection, which at first accelerates the droplets to relatively large velocities, and then tends to induce an approximately uniform inside temperature distribution so that the drop experiences an effective temperature gradient that is much smaller than the unperturbed one and, consequently, decelerates.
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.
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. PMID:19434848
A study of the effects of macrosegregation and buoyancy-driven flow in binary mixture solidification
Sinha, S. K.; Sundararajan, T.; Garg, V. K.
1993-01-01
A generalized anisotropic porous medium approach is developed for modelling the flow, heat and mass transport processes during binary mixture solidification. Transient predictions are obtained using FEM, coupled with an implicit time-marching scheme, for solidification inside a two-dimensional rectangular enclosure. A parametric study focusing attention on the effects of solutal buoyancy and thermal buoyancy is presented. It is observed that three parameters, namely the thermal Rayleigh number, the solutal Rayleigh number, and the relative density change parameter, significantly alter the flow fields in the liquid and the mushy regions. Depending upon the nature of these flow fields, the solute enrichment caused by macrosegregation may occur in the top or the bottom region of the enclosure.
Bhatia, Subhash C.; Sangwan, Jasbir; Rani, Ruman; Bhatia, Rachna
2011-10-01
Densities, ρ, viscosities, η, speeds of sound, u, and refractive indices, n D, of binary liquid mixtures of 2-octanol with 1,2-dichlorobenzene, 1,3-dichlorobenzene, and 1,2,4-trichlorobenzene have been measured over the entire range of composition at 298.15 K, 303.15 K, and 308.15 K and at atmospheric pressure. From the experimental data of the density, speed of sound, viscosity, and refractive index, the values of the excess molar volume, V E, deviations in isentropic compressibility, Δ κ S , and deviations in molar refraction, Δ R have been calculated. The calculated excess and deviation functions have been analyzed in terms of molecular interactions and structural effects.
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.
Thermodynamic scaling of the shear viscosity of Mie n-6 fluids and their binary mixtures
International Nuclear Information System (INIS)
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
Thermodynamic scaling of the shear viscosity of Mie n-6 fluids and their binary mixtures
Delage-Santacreu, Stephanie; Galliero, Guillaume; Hoang, Hai; Bazile, Jean-Patrick; Boned, Christian; Fernandez, Josefa
2015-05-01
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.
Prediction of surface tension of binary mixtures with the parachor method
Němec Tomáš
2015-01-01
The parachor method for the estimation of the surface tension of binary mixtures is modified by considering temperature-dependent values of the parachor parameters. The temperature dependence is calculated by a least-squares fit of pure-solvent surface tension data to the binary parachor equation utilizing the Peng-Robinson equation of state for the calculation of equilibrium densities. A very good agreement between experimental binary surface tension data and the predictions of the modified ...
Effects of a temperature dependent viscosity on thermal convection in binary mixtures
Hilt, Markus; Glässl, Martin; Zimmermann, Walter
2013-01-01
We investigate the effect of a temperature dependent viscosity on the onset of thermal convection in a horizontal layer of a binary fluid mixture that is heated from below. For an exponential temperature dependence of the viscosity, we find in binary mixtures as a function of a positive separation ratio and beyond a certain viscosity contrast a discontinuous transition between two stationary convection modes having a different wavelength. In the range of negative values of the separation rati...
Lattice Boltzmann Study of Velocity Behaviour in Binary Mixtures Under Shear
Xu, Aiguo; Gonnella, G.
2003-01-01
We apply lattice Boltzmann methods to study the relaxation of the velocity profile in binary fluids under shear during spinodal decomposition. In simple fluids, when a shear flow is applied on the boundaries of the system, the time required to obtain a triangular profile is inversely proportional to the viscosity and proportional to the square of the size of the system. We find that the same behaviour also occurs for binary mixtures, for any component ratio in the mixture and independently fr...
Mass dependence of shear viscosity in a binary fluid mixture: mode-coupling theory.
Ali, Sk Musharaf; Samanta, Alok; Choudhury, Niharendu; Ghosh, Swapan K
2006-11-01
An expression for the shear viscosity of a binary fluid mixture is derived using mode-coupling theory in order to study the mass dependence. The calculated results on shear viscosity for a binary isotopic Lennard-Jones fluid mixture show good agreement with results from molecular dynamics simulation carried out over a wide range of mass ratio at different composition. Also proposed is a new generalized Stokes-Einstein relation connecting the individual diffusivities to shear viscosity. PMID:17279895
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...
International Nuclear Information System (INIS)
The free energy for mixtures of about ten species which are chemically reacting is calculated. In order to have accurate results near the freezing line, excess properties are deduced from a modern statistical mechanics theory. Intermolecular potentials for like molecules are fitted to give good agreement with shock experiments in pure liquid samples, and mixture properties come naturally from the theory. The stationary Chapman-Jouguet detonation wave is calculated with a chemical equilibrium computer code and results are in good agreement with experiment for a lot of various explosives. One then study gas-gas equilibria in a binary mixture and show the extreme sensitivity of theoretical phase diagrams to the hypothesis of the model (author)
Self-assembly of azobenzene bilayer membranes in binary ionic liquid-water nanostructured media.
Kang, Tejwant Singh; Ishiba, Keita; Morikawa, Masa-aki; Kimizuka, Nobuo
2014-03-11
Anionic azobenzene-containing amphiphile 1 (sodium 4-[4-(N-methyl-N-dodecylamino)phenylazo]benzenesulfonate) forms ordered bilayer membranes in binary ionic liquid (1-ethyl-3-methylimidazolium ethyl sulfate, [C2mim][C2OSO3])-water mixtures. The binary [C2mim][C2OSO3]-water mixture is macroscopically homogeneous at any mixing ratio; however, it possesses fluctuating nanodomains of [C2mim][C2OSO3] molecules as observed by dynamic light scattering (DLS). These nanodomains show reversible heat-induced mixing behavior with water. Although the amphiphile 1 is substantially insoluble in pure water, it is dispersible in the [C2mim][C2OSO3]-water mixtures. The concentration of [C2mim][C2OSO3] and temperature exert significant influences on the self-assembling characteristics of 1 in the binary media, as shown by DLS, transmission electron microscopy (TEM), UV-vis spectroscopy, and zeta-potential measurements. Bilayer membranes with rod- or dotlike nanostructures were formed at a lower content of [C2mim][C2OSO3] (2-30 v/v %), in which azobenzene chromophores adopt parallel molecular orientation regardless of temperature. In contrast, when the content of [C2mim][C2OSO3] is increased above 60 v/v %, azobenzene bilayers showed thermally reversible gel-to-liquid crystalline phase transition. The self-assembly of azobenzene amphiphiles is tunable depending on the volume fraction of [C2mim][C2OSO3] and temperature, which are associated with the solvation by nanoclusters in the binary [C2mim][C2OSO3]-water media. These observations clearly indicate that mixtures of water-soluble ionic liquids and water provide unique and valiant environments for ordered molecular self-assembly. PMID:24528277
Coarsening dynamics of binary liquids with active rotation.
Sabrina, Syeda; Spellings, Matthew; Glotzer, Sharon C; Bishop, Kyle J M
2015-11-21
Active matter comprised of many self-driven units can exhibit emergent collective behaviors such as pattern formation and phase separation in both biological (e.g., mussel beds) and synthetic (e.g., colloidal swimmers) systems. While these behaviors are increasingly well understood for ensembles of linearly self-propelled "particles", less is known about the collective behaviors of active rotating particles where energy input at the particle level gives rise to rotational particle motion. A recent simulation study revealed that active rotation can induce phase separation in mixtures of counter-rotating particles in 2D. In contrast to that of linearly self-propelled particles, the phase separation of counter-rotating fluids is accompanied by steady convective flows that originate at the fluid-fluid interface. Here, we investigate the influence of these flows on the coarsening dynamics of actively rotating binary liquids using a phenomenological, hydrodynamic model that combines a Cahn-Hilliard equation for the fluid composition with a Navier-Stokes equation for the fluid velocity. The effect of active rotation is introduced though an additional force within the Navier-Stokes equations that arises due to gradients in the concentrations of clockwise and counter-clockwise rotating particles. Depending on the strength of active rotation and that of frictional interactions with the stationary surroundings, we observe and explain new dynamical behaviors such as "active coarsening" via self-generated flows as well as the emergence of self-propelled "vortex doublets". We confirm that many of the qualitative behaviors identified by the continuum model can also be found in discrete, particle-based simulations of actively rotating liquids. Our results highlight further opportunities for achieving complex dissipative structures in active materials subject to distributed actuation. PMID:26345231
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.; Michelsen, Michael Locht; Kontogeorgis, Georgios
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, eve...
DEFF Research Database (Denmark)
Fettouhi, André; Thomsen, Kaj
2010-01-01
A systematic investigation of the CPA model's performance within solid-liquid equilibria (SLE) in binary mixtures (methane + ethane, methane + heptane, methane + benzene, methane + CO2, ethane + heptane, ethane + CO2, 1-propanol + 1,4-dioxane, ethanol + water, 2-propanol + water) is presented. Th...
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.
Okumuş, Mustafa; Özgan, Şükrü; Kırık, İhsan; Kerli, Süleyman
2016-09-01
We present the thermal and optical properties of binary mixtures formed from hydrogen-bonded liquid crystal 4-hexylbenzoic acid (6BA) and 4-hexyl-4‧-biphenylcarbonitrile (6CB) mesogens. Phase transition temperatures and enthalpy values are evaluated by differential scanning calorimetry (DSC) and phases identified by polarized optic microscopy (POM). The experimental results obviously show that the 6BA/6CB binary mixtures exhibit nematic and smectic phases. The most interesting result is that although the smectic phase is not observed in pure components 6BA and 6CB, it is observed in their some binary mixtures. The thermal properties like phase peak temperatures, enthalpy changes and thermal span of binary mixtures are affected by depending on the mixture ratio. The nematic range increase in the binary mixture compared to the individual mesogen, and also the phase transition temperature values and the nematic thermal stability factor increase as heating rate increases. Furthermore, the calculated activation energy values show that the reorientation of the molecules during the phase transitions of the mixture occurs on an orderly basis.
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
implemented, leading to an entirely predictive method for densities of mixed compressed ionic liquids. Quantitative agreement with experimental data is obtained over wide ranges of conditions. Previously, the method has been applied to solubilities of sparingly soluble gases in ionic liquids and in organic......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 are...... solvents. Here we show results for heavier and more-than-sparingly solutes such as carbon dioxide and propane in ionic liquids....
International Nuclear Information System (INIS)
Osmotic coefficients of binary mixtures containing alcohols (ethanol, 1-propanol, and 2-propanol) and the ionic liquids 1-ethyl-3-methylimidazolium ethylsulfate and 1-ethyl-3-methylpyridinium ethylsulfate were determined at T = 323.15 K. Vapour pressure and activity coefficients of the studied systems were calculated from experimental data. The extended Pitzer model modified by Archer, and the modified NRTL model (MNRTL) were used to correlate the experimental data, obtaining standard deviations lower than 0.012 and 0.031, respectively. The mean molal activity coefficients and the excess Gibbs free energy of the studied binary mixtures were calculated from the parameters obtained with the extended Pitzer model of Archer.
Shear-induced quench of long-range correlations in a liquid mixture.
Wada, Hirofumi
2004-03-01
A static correlation function of concentration fluctuations in a (dilute) binary liquid mixture subjected to both a concentration gradient and uniform shear flow is investigated within the framework of fluctuating hydrodynamics. It is shown that a well-known |c|(2)/k(4) long-range correlation at large wave numbers k crosses over to a weaker divergent one at wave numbers satisfying kviscosity of the mixture, respectively. The result will provide the possibility to observe the shear-induced suppression of a long-range correlation experimentally by using, for example, a low-angle light scattering technique. PMID:15089275
Observations of homogeneous phase separation in liquid He3-He4 mixtures
Hoffer, J. K.; Campbell, L. J.; Bartlett, R. J.
1980-01-01
The so-called miscibility gap that exists below the critical point in liquid He-3 - H-4 mixtures makes it possible to study binary phase composition, and the ensuing dispersions, in a system possessing an additional order parameter in one of the components. The physical behavior of a superfluid dispersion produced by pressure quenching an He-3 - He-4 mixture into the miscibility gap is described. The description applies both to quenches of homogeneous and phase-separated initial states in various regions of the miscibility gap.
The separation of solid and liquid components of mixtures
International Nuclear Information System (INIS)
An improved method of separating solid and liquid components of mixtures is described which is particularly suited for use in automated radioimmunoassay systems in the analysis of bound and free fractions. A second liquid, having a density intermediate between those of the solid and liquid components, is delivered to the solid/ liquid mixture to form a discrete layer below the mixture and the solid separates into this lower liquid layer assisted by centrifugal force. The second liquid of intermediate density is an aqueous solution of a highly hydrophilic and electrically non-polar solute, such as an aqueous sucrose solution. Further liquids of intermediate density and progressively higher density may be delivered to form further discrete layers below the initial layer of the second dense liquid. After separation of the solid and liquid components of the mixture, the supernatant liquid component of the original mixture is removed in a controlled and non-turbulent manner. The method is illustrated in radioimmunoassays for platelet β-thromboglobulin and human follicle stimulating hormone. (U.K.)
Features of non-congruent phase transition in modified Coulomb model of the binary ionic mixture
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
Directory of Open Access Journals (Sweden)
M. Damanakis
2004-03-01
Full Text Available
Our study covers thermodynamic performance quantities for binary refrigerant mixtures of R-32/R-134a with compositions of 20/80%, 30/70%, 40/60% by mass for a wide range of thermodynamic conditions (pressure: 0.2 - 3.0 MPa, temperature: 240 - 480 oK and saturated conditions. The primary thrust of the study is the calculation of coefficient of performance (COP values for refrigeration systems. Additional attention is also given to speed of sound data and to isentropic process changes.
The relevant COPs are derived based on a simplified reference refrigeration cycle with one stage compression and throttling, saturated vapor and no liquid sub-cooling prior to the throttling valve. The COP values are given for various condensing and evaporating temperatures. For all calculations, a Peng – Robinson type equation of state is used to determine the necessary fluid properties. The enthalpy, entropy, and constant-pressure and constant-volume specific heats as well as the k-type isentropic change exponents are presented for all mixtures for the range of thermodynamics conditions listed above. Comparisons are made illustrating the influence of pressure and temperature on the k-type exponents kp,v, kT,v, and kp,T, and on the ratio of specific heats k (k = cp/cv. Furthermore, graphs with speed of sound data for this extended range of conditions are also given.
Solid/liquid interfacial free energies in binary systems
Nason, D.; Tiller, W. A.
1973-01-01
Description of a semiquantitative technique for predicting the segregation characteristics of smooth interfaces between binary solid and liquid solutions in terms of readily available thermodynamic parameters of the bulk solutions. A lattice-liquid interfacial model and a pair-bonded regular solution model are employed in the treatment with an accommodation for liquid interfacial entropy. The method is used to calculate the interfacial segregation and the free energy of segregation for solid-liquid interfaces between binary solutions for the (111) boundary of fcc crystals. The zone of compositional transition across the interface is shown to be on the order of a few atomic layers in width, being moderately narrower for ideal solutions. The free energy of the segregated interface depends primarily upon the solid composition and the heats of fusion of the component atoms, the composition difference of the solutions, and the difference of the heats of mixing of the solutions.
Shear viscosity of liquid mixtures: Mass dependence
International Nuclear Information System (INIS)
Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model. (author)
International Nuclear Information System (INIS)
Highlights: • The solubility data of spironolactone form II in pure solvents and binary solvent mixtures were determined. • The experimental solubility data in pure solvents were correlated by three models. • The experimental solubility data in binary solvent mixtures were correlated by two models. • The dissolution thermodynamic properties of spironolactone form II were obtained. - Abstract: The solubility data of spironolactone form II in six pure solvents and binary solvent mixtures of ethyl acetate and methanol were measured over the temperature range from (278.85 to 317.75) K by using a dynamic method under atmospheric pressure. The results show that the solubility of spironolactone form II in pure solvents increases with increasing temperature while the solubility in binary solvent mixtures increases with the increasing of the fraction of ethyl acetate. This phenomenon is well explained by using relative dielectric constants of the solvents. The solubility data of spironolactone form II in pure solvents were well correlated by the modified Apelblat equation, the Wilson model and the NRTL model while the solubility of spironolactone form II in binary solvent mixtures were correlated by the modified Apelblat equation and the CNIBS/R-K model. Furthermore, the thermodynamic properties of the dissolution process of spironolactone form II were also determined by using the van’t Hoff equation
Chattoraj, Shyamtanu; Chowdhury, Rajdeep; Ghosh, Shirsendu; Bhattacharyya, Kankan
2013-06-01
Diffusion of four coumarin dyes in a binary mixture of dimethyl sulfoxide (DMSO) and glycerol is studied using fluorescence correlation spectroscopy (FCS). The coumarin dyes are C151, C152, C480, and C481. In pure DMSO, all the four dyes exhibit a very narrow (almost uni-modal) distribution of diffusion coefficient (Dt). In contrast, in the binary mixtures all of them display a bimodal distribution of Dt with broadly two components. One of the components of Dt corresponds to the bulk viscosity. The other one is similar to that in pure DMSO. This clearly indicates the presence of two distinctly different nano-domains inside the binary mixture. In the first, the micro-environment of the solute consists of both DMSO and glycerol approximately at the bulk composition. The other corresponds to a situation where the first layer of the solute consists of DMSO only. The burst integrated fluorescence lifetime (BIFL) analysis also indicates presence of two micro-environments one of which resembles DMSO. The relative contribution of the DMSO-like environment obtained from the BIFL analysis is much larger than that obtained from FCS measurements. It is proposed that BIFL corresponds to an instantaneous environment in a small region (a few nm) around the probe. FCS, on the contrary, describes the long time trajectory of the probes in a region of dimension ˜200 nm. The results are explained in terms of the theory of binary mixtures and recent simulations of binary mixtures containing DMSO.
Transport of Binary Mixture of Adsorbable Gases in Vycor Glass
Czech Academy of Sciences Publication Activity Database
Čermáková, Jiřina; Yang, J.; Uchytil, Petr; Seidel-Morgenstern, A.
Praha : Process Engineering Publisher, 2004, s. 670. ISBN 80-86059-40-5. [International Congress of Chemical and Process Engineering CHISA 2004 /16./. Praha (CZ), 22.08.2004-26.08.2004] R&D Projects: GA AV ČR IAA4072402 Institutional research plan: CEZ:AV0Z4072921 Keywords : vycor glass * binary adsorption * transport Subject RIV: CF - Physical ; Theoretical Chemistry
Binary Homogenous Nucleation of Sulfuric Acid and Water Mixture
Czech Academy of Sciences Publication Activity Database
Brus, David; Hyvärinen, A-P.; Lihavainen, H.; Viisanen, Y.; Kulmala, M.
Thessaloniki : Hellenic Association for Aerosol Research, 2008, T03A036P. [European Aerosol Conference 2008. Thessaloniki (GR), 24.08.2008-29.08.2008] Institutional research plan: CEZ:AV0Z40720504 Keywords : binary homogeneou nucleation * laminar flow chamber Subject RIV: CF - Physical ; Theoretical Chemistry
Transport properties of supercritical fluids and their binary mixtures
International Nuclear Information System (INIS)
The molecular dynamics of the two supercritical fluids most applied in industry and some of their mixtures are characterized by their self-diffusion coefficients Di, 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 CO2, mixtures with C6H6, H2, CH3COOH and CH3OH were investigated. The NH3 mixtures include C6H6, (CH3)3N, CH3CN and CH3OH
Transport properties of supercritical fluids and their binary mixtures
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.
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
Volumetric properties of binary mixtures of dimethyl sulfoxide with amines from (293.15 to 363.15) K
International Nuclear Information System (INIS)
Highlights: ► Volumetric properties of mixtures of dimethyl sulfoxide with amines were studied. ► The excess molar volumes have been correlated using the Redlich–Kister equation. ► A set of parameters for the Redlich–Kister equation has been determined. ► The thermal expansion coefficients are represented and discussed. - Abstract: The new densities of binary mixtures of dimethyl sulfoxide (DMSO) with primary, secondary, and tertiary amines {2-aminoethanol (MEA), 2,2′-iminodiethanol (DEA), and bis(2-hydroxyethyl)methylamine (MDEA)} were measured at the atmospheric pressure for the temperatures ranging from (293.15 to 363.15) K over the entire composition range using an Anton Paar digital vibrating U-tube densimeter (model DMA 5000 M). A Redlich–Kister type equation was correlated using the excess molar volumes calculated with the experimental values and used to represent the densities of the liquid mixtures as a function of temperature and concentration. The thermal expansion coefficients of the pure components along with their binary mixtures using the experimental data are represented and discussed.
Directory of Open Access Journals (Sweden)
P. Losada-Pérez
2015-01-01
Full Text Available The phase transitions of binary lipid mixtures are studied by a combination of Peltier-element-based adiabatic scanning calorimetry (pASC and quartz crystal microbalance with dissipation monitoring (QCM-D. pASC, a novel type of calorimeter, provides valuable and unambiguous information on the heat capacity and the enthalpy, whereas QCM-D is proposed as a genuine way of determining phase diagrams by analysing the temperature dependence of the viscosity. Two binary mixtures of phospholipids with the same polar head and differing in the alkyl chain length, DMPC + DPPC and DMPC + DSPC, are discussed. Both techniques give consistent phase diagrams, which compare well with literature results, showing their capability to map the phase behaviour of pure lipids as well as lipid mixtures. This work can be considered as a departure point for further investigations on more complex lipid mixtures displaying relevant phases such as the liquid-ordered phase and solid-lipid interfaces with biologically functional importance.
International Nuclear Information System (INIS)
Highlights: • The large positive VmE values are obtained for the binary mixtures at 298.15 K. • Excess isentropic compressibilities for the binary mixtures are positive over the whole composition range. • The values of G∗E for all binary mixtures are negative over entire mole fraction. • Viscosities measured for the binary mixtures were correlated with values calculated by various viscosity models. • PEP theory, Bloomfield and Dewan model and Jouyban–Acree model are also used to correlate the experimental data. -- Abstract: Densities and viscosities of binary mixtures of n-decane with hexan-2-ol, heptan-2-ol and octan-2-ol have been measured over the entire range of composition at T = 298.15 K and at atmospheric pressure. From the experimental values of density and viscosity, the excess molar volumes (VmE) and excess Gibbs energy of activation of viscous flow (G∗E) have been calculated. These results were fitted to Redlich–Kister polynomial equations to estimate the binary coefficients and standard errors. Jouyban–Acree model is used to correlate the experimental values of density, viscosity and ultrasonic velocity at T = 298.15 K. The results of the viscosity-composition are discussed in the light of various viscosity semi-empirical equations. The experimental results have been used to test the applicability of the Prigogine–Flory–Patterson (PFP) theory. The values of Δln η have also been analysed using Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behaviour between the mixtures
Study of intermolecular interactions in binary mixtures of ethanol in methanol
Maharolkar, Aruna P.; Khirade, P. W.; Murugkar, A. G.
2016-05-01
Present paper deals with study of physicochemical properties like viscosity, density and refractive index for the binary mixtures of ethanol and methanol over the entire concentration range were measured at 298.15 K. The experimental data further used to determine the excess properties viz. excess molar volume, excess viscosity, excess molar refraction. The values of excess properties further fitted with Redlich-Kister (R-K Fit) equation to calculate the binary coefficients and standard deviation. The resulting excess parameters are used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures. Excess parameters indicate structure making factor in the mixture predominates in the system.
Almasi, Mohammad
2014-11-01
Densities and viscosities for binary mixtures of Diethanolamine (DEA) + 2 alkanol (2 propanol up to 2 pentanol) were measured over the entire composition range and temperature interval of 293.15-323.15 K. From the density and viscosity data, values of various properties such as isobaric thermal expansibility, excess isobaric thermal expansibility, partial molar volumes, excess molar volumes and viscosity deviations were calculated. The observed variations of these parameters, with alkanols chain length and temperature, are discussed in terms of the intermolecular interactions between the unlike molecules of the binary mixtures. The ability of the perturbed chain statistical associating fluid theory (PC-SAFT) to correlate accurately the volumetric behavior of the binary mixtures is demonstrated.
Mukherjee, Arnab; Bhattacharyya, Sarika; Bagchi, Biman
2002-01-01
Extensive isothermal-isobaric (NPT) molecular dynamics simulations at many different temperatures and pressures have been carried out in the well-known Kob-Andersen binary mixture model to monitor the effect of pressure (P) and temperature (T) on the dynamic properties such as the viscosity (\\eta) and the self-diffusion (Di) coefficients of the binary system. The following results have been obtained: (i) Compared to temperature, pressure is found to have a weaker effect on the dynamical prope...
Mixture for solidification of liquid radioactive wastes into stable forms
International Nuclear Information System (INIS)
A mixture is proposed for cementing liquid radioactive wastes into chemically stable, mechanically strong, transportable and storable forms. The mixture consists of 60-80 wt.% Portland cement, 5-15 wt.% flue silica dust and 15-25 wt.% zeolitic tuffite. (Z.S.)
Lattice Boltzmann Study of Velocity Behaviour in Binary Mixtures Under Shear
Xu, A; Xu, Aiguo
2003-01-01
We apply lattice Boltzmann methods to study the relaxation of the velocity profile in binary fluids under shear during spinodal decomposition. In simple fluids, when a shear flow is applied on the boundaries of the system, the time required to obtain a triangular profile is inversely proportional to the viscosity and proportional to the square of the size of the system. We find that the same behaviour also occurs for binary mixtures, for any component ratio in the mixture and independently from the time when shear flow is switched on during phase separation.
Effects of a temperature dependent viscosity on thermal convection in binary mixtures
Hilt, Markus; Zimmermann, Walter
2013-01-01
We investigate the effect of a temperature dependent viscosity on the onset of thermal convection in a horizontal layer of a binary fluid mixture that is heated from below. For an exponential temperature dependence of the viscosity, we find in binary mixtures as a function of a positive separation ratio and beyond a certain viscosity contrast a discontinuous transition between two stationary convection modes having a different wavelength. In the range of negative values of the separation ratio, a (continuous or discontinuous) transition from an oscillatory to a stationary onset of convection occurs beyond a certain viscosity contrast, and for large values of the viscosity ratio, the oscillatory onset of convection is suppressed.
Travelling waves near a critical point of a binary fluid mixture
Gouin, Henri; Ruggeri, Tommaso; 10.1016/j.ijnonlinmec.2011.09.016
2011-01-01
Travelling waves of densities of binary fluid mixtures are investigated near a critical point. The free energy is considered in a non-local form taking account of the density gradients. The equations of motions are applied to a universal form of the free energy near critical conditions and can be integrated by a rescaling process where the binary mixture is similar to a single fluid. Nevertheless, density solution profiles obtained are not necessarily monotonic. As indicated in Appendix, the results might be extended to other topics like finance or biology.
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.
Apparatus for separating a liquid carried along in a gas-liquid mixture
International Nuclear Information System (INIS)
The invention concerns an apparatus for separating a liquid entrained in a gas and liquid mixture and, in particular, the separators for removing the moisture entrained in the saturated steam of nuclear steam generators
Study of Binary Mixture Adsorption on Vycor Glass
Czech Academy of Sciences Publication Activity Database
Čermáková, Jiřina
Geesthacht : GKSS Research Centre, 2004 - (Castano, M.; Schipolowski, T.; Siegert, M.), s. 22-23 [Network Young Membrains 6. Hamburg (DE), 22.09.2004-24.09.2004] R&D Projects: GA AV ČR IAA4072402 Institutional research plan: CEZ:AV0Z4072921 Keywords : vycor glass * adsorption * bynary mixture Subject RIV: CF - Physical ; Theoretical Chemistry
A new approach to study interaction parameters in cyanobiphenyl liquid crystal binary systems
International Nuclear Information System (INIS)
Highlights: • The phase transition of 7CB and 5CB liquid crystals studied using the DSC. • This work includes the determination of the eutectic in the 7CB/5CB mixture. • The excess functions and interaction parameters calculated in the 7CB/5CB mixtures. • The P∗ randomicity parameter used to describe the phase transitions of C–N and N–I. • A small amount of P∗ showed a non-random identity of the C–N phase transition. - Abstract: The phase transition of heptylcyanobiphenyl 7CB and pentylcyanobiphenyl 5CB liquid crystals was investigated using the differential scanning calorimetry DSC technique. Then, the phase transition of different compositions of 7CB/5CB binary mixture was studied to determine the eutectic point. The phase diagram of mentioned binary system in 7CB mole fraction of 0.45 at T = 273.45 K is in good agreement with that of predicted from Schroder–van Laar equation. The thermodynamic excess functions and interaction parameters were calculated to describe the phase transition physically using the non-random mixing for the first time. The P∗ randomicity parameter was used to describe the phase transitions of C–N and N–I in which a small amount of P∗ shows a non-random identity of C–N phase transition. Contrarily, the P∗ is greater in N–I phase transition showing a random mixing process
Analytical Solutions for Some Simple Flows of a Binary Mixture of Incompressible Newtonian Fluids
BARIŞ, Serdar
2002-01-01
The problems dealing with some simple flows of a mixture of two incompressible Newtonian fluids have been analysed. By using the theory of binary mixtures of Newtonian fluids, the equations governing the velocity fields are reduced to a system of coupled ordinary differential equations. In the case of non-inertial flow the analytical solutions of these equations have been obtained for the following three problems: (i) the parallel flow with a free surface; (ii) the flow between inter...
N. Jaya Madhuri; Naidu, P S; Glory, J.; K. Ravindra Prasad
2011-01-01
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 th...
Navier-Stokes transport coefficients of $d$-dimensional granular binary mixtures at low density
Garzo, Vicente; Montanero, Jose Maria
2006-01-01
The Navier-Stokes transport coefficients for binary mixtures of smooth inelastic hard disks or spheres under gravity are determined from the Boltzmann kinetic theory by application of the Chapman-Enskog method for states near the local homogeneous cooling state. It is shown that the Navier-Stokes transport coefficients are not affected by the presence of gravity. As in the elastic case, the transport coefficients of the mixture verify a set of coupled linear integral equations that are approx...
Shear viscosity for a heated granular binary mixture at low-density
Montanero, J. M.; Garzo, V.
2002-01-01
The shear viscosity for a heated granular binary mixture of smooth hard spheres at low-density is analyzed. The mixture is heated by the action of an external driving force (Gaussian thermostat) which exactly compensate for cooling effects associated with the dissipation of collisions. The study is made from the Boltzmann kinetic theory, which is solved by using two complementary approaches. First, a normal solution of the Boltzmann equation via the Chapman-Enskog method is obtained up to fir...
Hofmann, A.; Migeot, M.; Hanemann, T.
2016-01-01
Temperature dependent viscosity, conductivity, and density data of binary mixtures containing ethylene carbonate (EC) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)azanide (EMIM-TFSA) were determined at atmospheric pressure in a wide temperature range of (20 to 120) °C. Additionally, differential scanning calorimetry (DSC) measurements were performed from (−120 to +100) °C to characterize phase behavior of the mixtures. On the basis of the experimental data it is demonstrated t...
Application of the finite volume method in the simulation of saturated flows of binary mixtures
International Nuclear Information System (INIS)
This work presents the simulation of saturated flows of an incompressible Newtonian fluid through a rigid, homogeneous and isotropic porous medium. The employed mathematical model is derived from the Continuum Theory of Mixtures and generalizes the classical one which is based on Darcy's Law form of the momentum equation. In this approach fluid and porous matrix are regarded as continuous constituents of a binary mixture. The finite volume method is employed in the simulation. (author)
Nonequilibrium Casimir-like Forces in Liquid Mixtures
Kirkpatrick, T. R.; Ortiz de Zárate, J. M.; Sengers, J. V.
2015-07-01
In this Letter, we consider a liquid mixture confined between two thermally conducting walls subjected to a stationary temperature gradient. While in a one-component liquid nonequilibrium fluctuation forces appear inside the liquid layer, nonequilibrium fluctuations in a mixture induce a Casimir-like force on the walls. The physical reason is that the temperature gradient induces large concentration fluctuations through the Soret effect. Unlike temperature fluctuations, nonequilibrium concentration fluctuations are also present near a perfectly thermally conducting wall. The magnitude of the fluctuation-induced Casimir force is proportional to the square of the Soret coefficient and is related to the concentration dependence of the heat and volume of mixing.
International Nuclear Information System (INIS)
The liquid-solid interface between a silicon substrate and the binary mixture perfluoromethylcyclohexane (PFMC) and 2-propanol (IP) is examined by x-ray specular reflectivity and diffuse scattering under grazing angles. The wetting films between the PFMC-rich phase and the substrate are characterized with respect to the density profile and lateral fluctuations. We find that the liquid-liquid interface of the film is anomalously broadened as compared to capillary wave theory. This broadening is caused by a locally slow variation of the density between the liquid phases and marks an adsorption profile that does not reflect the bulk properties of the film phase. Essentially the same behavior is present for a fused silica substrate
International Nuclear Information System (INIS)
Graphical abstract: The densities and ultrasonic speeds of the binary mixtures over the entire composition range were measured at various temperatures at atmospheric pressure. The excess molar volumes, isentropic compressibilities, and molar isentropic compressions have been calculated. The variations of these parameters with composition and temperature are discussed. The IR spectra were recorded they further supported the conclusion drawn from excess parameters, which indicates the presence of intermolecular hydrogen bonding between the oxygen atom of DMAE molecules and hydrogen atom of methanol and ethanol molecules in these mixtures.. - Highlights: • The study reports density and ultrasonic velocity data of 2-(dimethylamino)ethanol + methanol/ethanol mixtures. • To elucidate the interactions in 2-(dimethylamino)ethanol + methanol/ethanol binary mixtures. • Provides information on nature and relative strength of interactions in these mixtures. • Correlates physicochemical properties with interactions in these mixtures. - Abstract: The densities, ρ and ultrasonic speeds, u of the binary mixtures of 2-(dimethylamino)ethanol (DMAE) with methanol/ethanol, including those of pure liquids, over the entire composition range were measured at 298.15, 308.15 and 318.15 K. From the experimental data, the excess molar volumes, VmE and excess isentropic compressibilities, κsE have been calculated. The excess partial molar volumes, V¯m,1E and V¯m,2E and excess partial molar isentropic compressions, K¯s,m,1E and K¯s,m,2E over the whole composition range; and partial molar volumes, V¯m,1° and V¯m,2°, partial molar isentropic compressions, K¯s,m,1° and K¯s,m,2°, excess partial molar volumes, V¯m,1°E and V¯m,2°E, and excess partial molar isentropic compressions, K¯s,m,1°E and K¯s,m,2°E at infinite dilution have also been calculated. The variations of these parameters with composition and temperature are discussed in terms of intermolecular
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.
Fenz, W; Mryglod, I M; Prytula, O; Folk, R
2009-08-01
Correlation functions and transport coefficients of self-diffusion and shear viscosity of a binary Lennard-Jones mixture with components differing only in their particle mass are studied up to high values of the mass ratio mu, including the limiting case mu = infinity, for different mole fractions x. Within a large range of x and mu the product of the diffusion coefficient of the heavy species D(2) and the total shear viscosity of the mixture eta(m) is found to remain constant, obeying a generalized Stokes-Einstein relation. At high liquid density, large mass ratios lead to a pronounced cage effect that is observable in the mean square displacement, the velocity autocorrelation function, and the van Hove correlation function. PMID:19792112
Roy, Mahendra Nath; Sah, Radhey Shyam; Pradhan, Prasanna
2010-02-01
Densities and viscosities were measured for binary mixtures of isoamyl alcohol with 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol over the entire range of composition at 303.15 K, 313.15 K, and 323.15K and ultrasonic speeds and refractive indices at 303.15 K under atmospheric pressure. From the experimental values of density, viscosity, ultrasonic speed, and refractive index, the values of excess molar volume ( V E), viscosity deviations (Δ η), deviations in isentropic compressibility (Δ K S ), and excess molar refraction (Δ R) have been calculated. The excess or deviation properties were found to be either negative or positive, depending on the molecular interactions and the nature of liquid mixtures.
Fenz, W.; Mryglod, I. M.; Prytula, O.; Folk, R.
2009-08-01
Correlation functions and transport coefficients of self-diffusion and shear viscosity of a binary Lennard-Jones mixture with components differing only in their particle mass are studied up to high values of the mass ratio μ , including the limiting case μ=∞ , for different mole fractions x . Within a large range of x and μ the product of the diffusion coefficient of the heavy species D2 and the total shear viscosity of the mixture ηm is found to remain constant, obeying a generalized Stokes-Einstein relation. At high liquid density, large mass ratios lead to a pronounced cage effect that is observable in the mean square displacement, the velocity autocorrelation function, and the van Hove correlation function.
Energy Technology Data Exchange (ETDEWEB)
Abe, Yoshiyuki; Iwasaki, Akira
1999-07-01
Although non-azeotropic mixtures are considered to be promising working fluids in advanced energy conversion systems, the primary technical problems in the heat transfer degradation in phase change processes cause economical handicap to wide-spread applications. The boiling behavior of mixtures still remains a number of basic questions being not answered yet, and the present authors believe that the most essential information for the boiling process in non-azeotropic mixtures is how temperature and concentration profiles are developed around the bubbles. The present study attempts at understanding fundamental heat and mass transfer mechanisms in nucleate pool boiling of non-azeotropic binary mixtures, and with the knowledge to develop a passive boiling heat transfer enhancement eventually. To this end, the authors have employed microgravity environment for rather detailed observation around vapor bubbles in the course of boiling inception and bubble growth. A two-wavelength Mach-Zehnder interferometer has been developed, which withstands mechanical shock caused by gravity change from very low gravity of the order of 10{sup {minus}5} g to relatively high gravity of approximately 8 g exposed during deceleration period. A series of experiments on single vapor bubbles for CFC113 single component and CFC12/CFC112 non-azeotropic binary mixture have been conducted under a high quality microgravity conditions available in 10-second free-fall facility of Japan Microgravity Center (JAMIC). The results for single component liquid showed a strong influence due to Marangoni effect caused by the temperature profile around the bubble. The results for non-azeotropic binary mixture showed, however, considerably different behavior from single component liquid. Both temperature and concentration profiles around a single vapor bubble were evaluated from the interferograms. The temperature and concentration layers established around the bubbles were nearly one order of magnitude larger
Hopping in a supercooled binary Lennard-Jones liquid
DEFF Research Database (Denmark)
Schrøder, Thomas; Dyre, Jeppe
1998-01-01
A binary LennardJones liquid has been investigated by molecular dynamics at equilibrium supercooled conditions. At the lowest temperature investigated, hopping is present in the system as indicated by a secondary peak in 4r2Gs(r,t), where Gs(r,t) is the van Hove self correlation function. To......", as often argued, and that the system has a single-peaked distribution of hopping-distances centered around the characteristic intermolecular distance....
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.
Behavior of the Thermodynamic Properties of Binary Mixtures near the Critical Azeotrope
Directory of Open Access Journals (Sweden)
Azzedine Abbaci
2003-12-01
Full Text Available Abstract: In this work we investigate the critical line of binary azeotropic mixtures of acetone-n-pentane. We pinpoint the abnormal behavior of the critical density line as a function of the mole fraction of one of the component and show its influence on other thermodynamic properties such as the volume, the enthalpy and the entropy.
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; Marrucho, Isabel M.; Coutinho, Joao
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...
Smyrnakis, J.; Magiropoulos, M.; Kavoulakis, G. M.; Jackson, A. D.
2013-01-01
We derive solitary-wave solutions within the mean-field approximation in quasi-one-dimensional binary mixtures of Bose-Einstein condensates under periodic boundary conditions, for the case of an effective repulsive interatomic interaction. The particular gray-bright solutions that give the global energy minima are determined. Their characteristics and the associated dispersion relation are derived.
Self-Propulsion Mechanism of Active Janus Particles in Near-Critical Binary Mixtures
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
Noble gas, binary mixtures for commercial gas-cooled reactor systems
International Nuclear Information System (INIS)
Commercial gas cooled reactors employ helium as a coolant and working fluid for the Closed Brayton Cycle (CBC) turbo-machines. Helium has the highest thermal conductivity and lowest dynamic viscosity of all noble gases. This paper compares the relative performance of pure helium to binary mixtures of helium and other noble gases of higher molecular weights. The comparison is for the same molecular flow rate, and same operating temperatures and geometry. Results show that although helium is a good working fluid because of its high heat transfer coefficient and significantly lower pumping requirement, a binary gas mixture of He-Xe with M = 15 gm/mole has a heat transfer coefficient that is ∼7% higher than that of helium and requires only 25% of the number stages of the turbo-machines. The binary mixture, however, requires 3.5 times the pumping requirement with helium. The second best working fluid is He-Kr binary mixture with M = 10 gm/mole. It has 4% higher heat transfer coefficient than He and requires 30% of the number of stages in the turbo-machines, but requires twice the pumping power
Mandai, Toshihiko; Tsuzuki, Seiji; Ueno, Kazuhide; Dokko, Kaoru; Watanabe, Masayoshi
2015-01-28
We prepared a series of binary mixtures composed of certain K salts (KX) and pentaglyme (G5) with different salt concentrations and anionic species ([X](-): [(CF3SO2)2N](-) = [TFSA](-), [CF3SO3](-) = [TfO](-), [C4F9SO3](-) = [NfO](-), PF6(-), SCN(-)), and characterized them with respect to their phase diagrams, solvate structures, and physicochemical properties. Their phase diagrams and thermal stability strongly implied the formation of equimolar complexes. Single-crystal X-ray crystallography was performed on certain equimolar complexes, which revealed that G5 molecules coordinate to K(+) cations in a characteristic manner, like 18-crown-6 ether in the crystalline state, irrespective of the paired anions. The solvate structures in the molten state were elucidated by a combination of temperature-dependent Raman spectroscopy and X-ray crystallography. A drastic spectral variation was observed in the [K(G5)1][TfO] Raman spectra, indicating that solvate structures in the crystalline state break apart upon melting. The solvate stability of [K(G5)1]X is closely related to the ion-ion interaction of the parent salts. A stable solvate forms when the ion-dipole interaction between K(+) and G5 overwhelms the ion-ion interaction between K(+) and X(-). Furthermore, the physicochemical properties of certain equimolar mixtures were evaluated. A Walden plot clearly reflects the ionic nature of the molten equimolar complexes. Judging from the structural characteristics and dissociativity, we classified [K(G5)1]X into two groups, good and poor solvate ionic liquids. PMID:25501925
Mass transport thermodynamics in nonisothermal molecular liquid mixtures
Energy Technology Data Exchange (ETDEWEB)
Semenov, Semen N [Institute for Biochemical Physics, Russian Academy of Sciences, Moscow (Russian Federation); Schimpf, M E [Department of Chemistry and Biochemistry, Boise State University, Boise, ID (United States)
2009-10-31
Mass transport in a nonisothermal binary molecular mixture is systematically discussed in terms of nonequilibrium thermodynamics, which for the first time allows a consistent and unambiguous description of the process. The thermodynamic and hydrodynamic approaches are compared, revealing that nonequilibrium thermodynamics and physicochemical hydrodynamics yield essentially the same results for molecular systems. The applicability limits for the proposed version of the thermodynamic approach are determined for large particles. (methodological notes)
International Nuclear Information System (INIS)
Highlights: ► The temperature dependence of the physical properties of [PMim][NTf2] was studied. ► Physical properties of its binary mixtures with alcohols were determined at 298.15 K. ► The thermal expansion coefficient of the pure ionic liquid was calculated. ► The heat capacity of the pure ionic liquid at 298.15 K was determined. ► The excess properties of binary mixtures were adjusted with Redlich–Kister equation. - Abstract: In this paper, physical properties of a high purity sample of the ionic liquid 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf2], and its binary mixtures with methanol, ethanol, 1-propanol, and 2-propanol were measured at atmospheric pressure. The temperature dependence of density, refractive index and speed of sound (293.15 to 343.15) K and dynamic viscosity (298.15 to 343.15) K were studied at atmospheric pressure by conventional techniques for the pure ionic liquid. For its mixtures with alcohols, density, speed of sound, and refractive index were measured at T = 298.15 K over the whole composition range. The thermal expansion coefficient of the [PMim][NTf2] was calculated from the experimental results using an empirical equation, and values of the excess molar volume, excess refractive index, and excess molar isentropic compressibility for the binary systems at the above mentioned temperature, were calculated and fitted to the Redlich–Kister equation. The heat capacity of the pure ionic liquid at T = 298.15 K was determined using DSC.
International Nuclear Information System (INIS)
Among the multiple substances that affect freshwater ecosystems, uranium and selenium are two pollutants found worldwide in the environment, alone and in mixture. The aim of this thesis work was to investigate the effect of uranium and selenium mixture on daphnia (Daphnia magna). Studying effects of a mixture requires the assessment of the effect of single substances. Thus, the first experiments were performed on single substance. Acute toxicity data were obtained: EC50 48h = 0, 39±0, 04 mg.L-1 for uranium and EC50 48h 1, 86±0, 85 mg.L-1 for selenium. Chronic effects were also studied. Data on fecundity showed an EC10 reproduction of 14±7 μg. L-1 for uranium and of 215±25 μg. L-1 for selenium. Uranium-selenium mixture toxicity experiments were performed and revealed an antagonistic effect. This study further demonstrates the importance of taking into consideration different elements in binary mixture studies such as the choice of reference models (concentration addition or independent action), statistical method, time exposure and endpoints. Using integrated parameters like energy budget was shown to be an interesting way to better understand interactions. An approach including calculation of chemical speciation in the medium and bioaccumulation measurements in the organism permits assumptions to be made on the nature of possible interactions between mixture components (toxico-dynamic et toxico-kinetic interactions). (author)
Homogeneous bubble nucleation in binary systems of liquid solvent and dissolved gas
Němec, Tomáš
2016-03-01
A formulation of the classical nucleation theory (CNT) is developed for bubble nucleation in a binary system composed of a liquid solvent and a dissolved gas. The theoretical predictions are compared to the experimental nucleation data of four binary mixtures, i.e. diethylether - nitrogen, propane - carbon dioxide, isobutane - carbon dioxide, and R22 (chlorodifluoromethane) - carbon dioxide. The presented CNT formulation is found to improve the precision of the simpler theoretical method of Ward et al. [J. Basic Eng. 92 (10), 71-80, 1970] based on the weak-solution approximation. By analyzing the available experimental nucleation data, an inconsistency in the data reported by Mori et al. [Int. J. Heat Mass Transfer, 19 (10), 1153-1159, 1976] for propane - carbon dioxide and R22 - carbon dioxide is identified.
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.
Transport in a highly asymmetric binary fluid mixture.
Bastea, Sorin
2007-03-01
We present molecular dynamics calculations of the thermal conductivity and viscosities of a model colloidal suspension with colloidal particles roughly one order of magnitude larger than the suspending liquid molecules. The results are compared with estimates based on the Enskog transport theory and effective medium theories (EMT) for thermal and viscous transport. We find, in particular, that EMT remains well applicable for predicting both the shear viscosity and thermal conductivity of such suspensions when the colloidal particles have a "typical" mass, i.e., much larger than the liquid molecules. Very light colloidal particles on the other hand yield higher thermal conductivities, in disagreement with EMT. We also discuss the consequences of these results for some proposed mechanisms for thermal conduction in nanocolloidal suspensions. PMID:17500686
Mixing effects in the crystallization of supercooled quantum binary liquids
Energy Technology Data Exchange (ETDEWEB)
Kühnel, M.; Kalinin, A. [Institut für Kernphysik, J. W. Goethe-Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Fernández, J. M.; Tejeda, G.; Moreno, E.; Montero, S. [Laboratory of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain); Tramonto, F.; Galli, D. E. [Laboratorio di Calcolo Parallelo e di Simulazioni di Materia Condensata, Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Nava, M. [Laboratorio di Calcolo Parallelo e di Simulazioni di Materia Condensata, Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Computational Science, Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, Via Giuseppe Buffi 13, CH-6900 Lugano (Switzerland); Grisenti, R. E. [Institut für Kernphysik, J. W. Goethe-Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI - Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)
2015-08-14
By means of Raman spectroscopy of liquid microjets, we have investigated the crystallization process of supercooled quantum liquid mixtures composed of parahydrogen (pH{sub 2}) or orthodeuterium (oD{sub 2}) diluted with small amounts of neon. We show that the introduction of the Ne impurities affects the crystallization kinetics in terms of a significant reduction of the measured pH{sub 2} and oD{sub 2} crystal growth rates, similarly to what found in our previous work on supercooled pH{sub 2}-oD{sub 2} liquid mixtures [Kühnel et al., Phys. Rev. B 89, 180201(R) (2014)]. Our experimental results, in combination with path-integral simulations of the supercooled liquid mixtures, suggest in particular a correlation between the measured growth rates and the ratio of the effective particle sizes originating from quantum delocalization effects. We further show that the crystalline structure of the mixtures is also affected to a large extent by the presence of the Ne impurities, which likely initiate the freezing process through the formation of Ne-rich crystallites.
Transport in a highly asymmetric binary fluid mixture
Bastea, Sorin
2007-01-01
We present molecular dynamics calculations of the thermal conductivity and viscosities of a model colloidal suspension with colloidal particles roughly one order of magnitude larger than the suspending liquid molecules. The results are compared with estimates based on the Enskog transport theory and effective medium theories (EMT) for thermal and viscous transport. We find, in particular, that EMT remains well applicable for predicting both the shear viscosity and thermal conductivity of such...
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.
Liu, Hong; Qian, Hu-Jun; Zhao, Ying; Lu, Zhong-Yuan
2007-10-14
The influence of polymerization on the phase separation of binary immiscible mixtures has been investigated by the dissipative particle dynamics simulations in two dimensions. During polymerization, the bulk viscosity increases, which consequently slows down the spinodal decomposition process. The domain size growth is monitored in the simulations. The absence of 23 exponent for inertial hydrodynamic mechanism clearly reflects the suppressing effect of polymerization on the phase separation. Due to the increasing viscosity, the individual phase may be trapped in a metastable stage instead of the lamellar morphology identified for symmetric mixtures. Moreover, the polymerization induced phase separation in the binary miscible mixture has been studied. The domain growth is strongly dependent on the polymerization probability, which is naturally related to the activation energy for polymerization. The observed complex phase separation behavior is attributed to the interplay between the increasing thermodynamic driving force for phase separation and the increasing viscosity that suppresses phase separation as the polymerization proceeds. PMID:17935435
A combined ultrasonic flow meter and binary vapour mixture analyzer for the ATLAS silicon tracker
Bates, R.; Battistin, M.; Berry, S.; Berthoud, J.; Bitadze, A.; Bonneau, P.; Botelho-Direito, J.; Bousson, N.; Boyd, G.; Bozza, G.; Da Riva, E.; Degeorge, C.; Deterre, 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.
2013-02-01
We describe a combined ultrasonic instrument for gas flow metering and continuous real-time binary gas composition measurements. The combined flow measurement and mixture analysis algorithm employs sound velocity measurements in two directions in combination with measurements of the pressure and temperature of the process gas mixture. The instrument has been developed in two geometries following extensive computational fluid dynamics studies of various mechanical layouts. A version with an axial sound path has been used with binary gas flows up to 230 l.min-1, while a version with a sound path angled at 45° to the gas flow direction has been developed for use in gas flows up to 20000 l.min-1. The instrument with the axial geometry has demonstrated a flow resolution of flows up to 230 l.min-1 and a mixture resolution of 3.10-3 for C3F8/C2F6 molar mixtures with ~ 20 %C2F6. Higher mixture precision is possible in mixtures of gases with widely-differing molecular weight (mw): a sensitivity of 1yr) continuous study. A prototype instrument with 45° crossing angle has demonstrated a flow resolution of 1.9 % of full scale for linear flow velocities up to 15 ms-1. Although this development was motivated by a requirement of the ATLAS silicon tracker evaporative fluorocarbon cooling system, the developed instrument can be used in many applications where continuous knowledge of binary gas composition is required. Applications include the analysis of hydrocarbons, vapour mixtures for semi-conductor manufacture and anaesthetic gas mixtures.
International Nuclear Information System (INIS)
Highlights: • Binary mixtures of 1-butoxy-2-propanol with alcohols have been studied at different temperatures. • Strong H-bonding interactions between the components are confirmed that decreases with increasing chain length of alcohols. • Thermophysical and FT-IR spectroscopic studies strongly corroborate the experimental and computational analysis results. - Abstract: This paper reports densities (ρ) and speeds of sound (u) of 1-butoxy-2-propanol CH3(CH2)3OC3H6OH, 1-propanol CH3(CH2)2OH, 2-propanol (CH3)2CHOH, 1-butanol CH3(CH2)3OH and 2-butanol CH3CH2CH(OH)CH3 and their binary mixtures with 1-butoxy-2-propanol as a common component, measured at T = (293.15, 298.15, 303.15, 308.15 and 313.15) K over the entire composition range. These experimental values of density and speed of sound were used to calculate the values of excess molar volumes, VmE, deviations in molar isentropic compressibility Δκs and deviations in speed of sound uD. Further, experimental densities were used to estimate apparent molar volumes Vϕ,i, partial molar volumes V‾m,1, excess partial molar volumes V‾m,1E and their limiting values at infinite dilution Vϕ,i∞, V‾m,i∞ and V‾m,iE,∞ respectively. The variations observed in these properties, with composition and temperature, are discussed in terms of molecular interactions due to physical and chemical effects between the unlike molecules of the binary mixtures. These properties, especially excess functions, are found to be quite sensitive towards the intermolecular interactions in liquid mixtures. These excess functions and deviations have also been correlated using Redlich–Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors. FT-IR studies of these mixtures are also reported
Linear mixing rule in screened binary ionic mixtures
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.
Canongia Lopes, José N; Esperança, José M S S; de Ferro, André Mão; Pereiro, Ana B; Plechkova, Natalia V; Rebelo, Luis P N; Seddon, Kenneth R; Vázquez-Fernández, Isabel
2016-03-10
This study is centered on the thermophysical characterization of different families of alkylammonium nitrate ionic liquids and their binary mixtures, namely the determination at atmospheric pressure of densities, electric conductivities and viscosities in the 288.15 liquids with differing numbers of hydrogen bond donor groups: diethylammonium nitrate (two hydrogen bond donors), triethylammonium nitrate (one hydrogen bond donor) and tetraethylammonium nitrate (no hydrogen bond donors). Finally, the behavior of mixtures with different numbers of equivalent carbon atoms in the alkylammonium cations was analyzed. The results show a quasi-ideal behavior for all monoalkylammonium nitrate mixtures. In contrast, the other mixtures show deviations from ideality, namely when the difference in the number of carbon atoms present in the cations increases or the number of hydrogen bond donors present in the cation decreases. Overall, the results clearly show that, besides the length and distribution of alkyl chains present in a cation such as alkylammonium, there are other structural and interaction parameters that influence the thermophysical properties of both pure compounds and their mixtures. PMID:26886188
International Nuclear Information System (INIS)
Highlights: • Phase behavior of the binary systems containing largely different components. • Equation of state modeling of binary polar and non-polar systems by utilizing different mixing rules. • Three different mixing rules (one-parameter, two-parameters and Wong–Sandler) coupled with Peng–Robinson equation of state. • Two-parameter mixing rule shows promoting results compared to one-parameter mixing rule. • Wong–Sandler mixing rule is unable to predict saturated liquid densities with sufficient accuracy. - Abstract: The present study mainly focuses on the phase behavior modeling of asymmetric binary mixtures. Capability of different mixing rules and volume shift in the prediction of solubility and saturated liquid density has been investigated. Different binary systems of (alkane + alkanol), (alkane + alkane), (carbon dioxide + alkanol), and (carbon dioxide + alkane) are considered. The composition and the density of saturated liquid phase at equilibrium condition are the properties of interest. Considering composition and saturated liquid density of different binary systems, three main objectives are investigated. First, three different mixing rules (one-parameter, two parameters and Wong–Sandler) coupled with Peng–Robinson equation of state were used to predict the equilibrium properties. The Wong–Sandler mixing rule was utilized with the non-random two-liquid (NRTL) model. Binary interaction coefficients and NRTL model parameters were optimized using the Levenberg–Marquardt algorithm. Second, to improve the density prediction, the volume translation technique was applied. Finally, Two different approaches were considered to tune the equation of state; regression of experimental equilibrium compositions and densities separately and spontaneously. The modeling results show that there is no superior mixing rule which can predict the equilibrium properties for different systems. Two-parameter and Wong–Sandler mixing rule show promoting
Shear viscosity relaxation of a critical binary liquid.
Behrends, Ralph; Kaatze, Udo
2003-07-01
Two series of diffusion coefficients D are reported for the triethylamine-water binary critical mixture. One has been obtained from quasielastic light scattering measurements, the other one has been derived from broadband ultrasonic spectra, yielding the relaxation rate of order parameter fluctuations, and shear viscosity data. Using high frequency shear impedance spectrometry in the range 20-130 MHz, relaxations in the background part of the viscosity, resulting in viscoelastic mixture properties, have been found. Both series of D data agree either if a half-attenuation frequency distinctly smaller than the theoretical value Omega(1/2)=2.1 is used in the Bhattacharjee-Ferrell scaling function or if the viscosity extrapolated from the shear impedance measurements to low frequencies is applied to the Kawasaki-Ferrell relation. This extrapolated viscosity is smaller than the static shear viscosity measured with capillary viscosimeters. PMID:12935130
Viscosity of Liquid Crystal Mixtures in the Presence of Electroconvection
Nagaya, Tomoyuki; Satou, Yuki; Goto, Yoshitomo; Hidaka, Yoshiki; Orihara, Hiroshi
2016-07-01
We have experimentally investigated the viscosity of nematic liquid crystal mixtures of p-methoxybenzylidene-p'-n-butylaniline (MBBA) and p-ethoxybenzylidene-p'-cyanoaniline (EBCA) in the presence of electroconvection under an ac electric field with 60 Hz. Although the viscosity of the mixtures with negative dielectric anisotropy shows a characteristic decrease in the high-voltage regime, that with positive dielectric anisotropy shows a monotonic increase as the applied voltage is increased. The experimental results suggest that the decrease in viscosity observed only for the mixtures with negative dielectric anisotropy is attributed to the negative contribution of electric stress caused by the anisotropic director distribution of the turbulent state.
Observations of mass transport phenomena in multicomponent liquid mixtures
International Nuclear Information System (INIS)
Examples of surface tension effects on liquid behavior are common, such as liquid rising in a capillary tube or the beading of rain drops on a freshly waxed car. Usually through, the surface tension forces are small compared to other forces such as gravity. Situations exist, however, where the simple statement attributed to Marangoni can explain striking and unexpected observations. ''If for any reason difference of surface tension exist along a free liquid surface, liquid will flow toward the region of higher surface tension''. Such flows are called Marangoni flows. Observations of isotopic hydrogen fuel mixtures in cryogenic Inertial Confinement Fusion (ICF) targets can be explained on the basis of Marangoni flows. Additional experiments at KMS with common room temperature mixtures have produced similar results
Dielectrophoretic manipulation of the mixture of isotropic and nematic liquid
Kim, Soo-Dong; Lee, Bomi; Kang, Shin-Woong; Song, Jang-Kun
2015-01-01
In various applications involving liquid crystals, the manipulation of the nanoscale molecular assembly and microscale director alignment is highly useful. Here we show that a nematic–isotropic mixture, a unique bi-liquid system, has potential for the fabrication of microstructures having an ordered phase within a disordered phase, or vice versa. The volume expansion and shrinkage, migration, splitting, mergence and elongation of one phase within the other are easily accomplished via thermal ...
Effect of repeated presentation on sweetness intensity of binary and ternary mixtures of sweeteners.
Schiffman, Susan S; Sattely-Miller, Elizabeth A; Graham, Brevick G; Zervakis, Jennifer; Butchko, Harriett H; Stargel, W Wayne
2003-03-01
The purpose of the present study was to determine the effect of repeated presentation of the same sweet stimulus on sweetness intensity ratings. The sweet stimuli tested in this study were binary and ternary blends of 14 sweeteners that varied widely in chemical structure. A trained panel evaluated the sweetness intensity over four sips of a given mixture presented at 30 s intervals. The individual components in the binary sweetener combinations were intensity-anchored with 5% sucrose, while the individual sweeteners in the ternary mixtures were intensity-anchored with 3% sucrose (according to formulae developed previously). Each self-mixture was also evaluated (e.g. acesulfame-K-acesulfame-K). The main finding of this study was that mixtures consisting of two or three different sweeteners exhibited less reduction in sweetness intensity over four repeated sips than a single sweetener at an equivalent sweetness level. Furthermore, ternary combinations tended to be slightly more effective than binary combinations at lessening the effect of repeated exposure to a given sweet stimulus. These findings suggest that the decline in sweetness intensity experienced over repeated exposure to a sweet stimulus could be reduced by the blending of sweeteners. PMID:12714444
International Nuclear Information System (INIS)
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.
Ionic-Liquid Based Separation of Azeotropic Mixtures
DEFF Research Database (Denmark)
Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul
2014-01-01
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......methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria such as...... [C1MIM][DMP]. For the final evaluation, the best candidates for aqueous systems were used as entrainers, and then the vapor-liquid equilibrium (VLE) of the ternary systems containing ILs was predicted by the Non Random Two Liquids (NRTL) model to confirm the breaking of the azeotrope. Based on...
Mirzaev, S Z; Kaatze, U
2002-02-01
Between 200 kHz and 130 MHz, the ultrasonic attenuation spectrum of the ionic ethylammonium nitrate--n-octanol mixture of critical composition has been measured at various reduced temperatures (1.5 x 10(-4)viscosity and heat capacity data from the literature, the experimental spectra have been evaluated to yield the scaling function, with the background contribution to the spectra as the only adjustable parameter. Agreement, within the limits of experimental error, of the measured scaling function with that of the nonionic binary system ethanol--dodecane and with the theoretical predictions of the Bhattacharjee-Ferrell dynamic scaling model is found. The amplitude of the fluctuation correlation length xi(o) (=0.47 nm) and the amount of the coupling constant /g/ (=1.3) are rather high as compared to nonionic binary critical mixtures. The amplitude of the relaxation rate of order parameter fluctuations Gamma(o)(=2.6 x 10(8) s(-1)) exhibits an unusual small value, likely to the most part a reflection of the high viscosity and thus small diffusion coefficient of the ionic liquid. PMID:11863532
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.
International Nuclear Information System (INIS)
Highlights: • LLE data for dodecane + ethanol + 1-alkyl-imidazoluim-based ionic liquids (ILs). • ILs are [Mmim][MeSO4], [Emim][MeSO4], and [Bmim][MeSO4]. • Measurements at T = 298.15 K and 0.101 MPa, as well as at T = 313.15 K for [Mmim][MeSO4]. • Consistency of the tie-lines checked with the Othmer–Tobias and Hand equations. • Data correlated with the NRTL model. - Abstract: The ternary (liquid + liquid) equilibrium (LLE) data for mixtures of dodecane (C12H26) and ethanol with ionic liquids 1,3-dimethylimidazolium methylsulfate [Mmim][MeSO4], 1-ethyl-3-methylimidazolium methylsulfate, [Emim][MeSO4] and 1-butyl-3-methylimidazolium methylsulfate, [Bmim][MeSO4], were studied at T = 298.15 K and 0.101 MPa. The selectivity and solute distribution coefficient ratios determined from the data were used to examine the possibility of using these ionic liquids for extraction of ethanol from dodecane. The temperature dependency was investigated by measuring the LLE data for {dodecane + ethanol + [Mmim][MeSO4]} at T = 313.15 K and 0.101 MPa. The Othmer–Tobias and Hand equations were used to test the consistency of the tie-line data. The tie-line data were correlated with the Non-Random Two Liquid (NRTL) equation which provided a good model and representation for the experimental results
International Nuclear Information System (INIS)
Highlights: • Phase equilibrium data for propene and hexafluoropropylene. • Phase equilibrium data for propene and hexafluoropropylene oxide. • Systems exhibit pressure-maximum azeotropes. • Data well correlated by Peng–Robinson equation of state with the Wong–Sandler mixing rule. - Abstract: Isothermal (vapour + liquid) equilibrium data (P–x–y) are presented for the 1-propene 1,1,2,3,3,3-hexafluoro-1-propene and the 1-propene + 2,2,3-trifluoro-3-(trifluoromethyl)oxirane binary systems. Both binary systems were studied at five temperatures, ranging from (279.36 to 318.09) K, at pressures up to 2 MPa. The experimental (vapour + liquid) equilibrium data were measured using an apparatus based on the “(static + analytic)” method incorporating a single movable Rapid On-Line Sampler-Injector to sample the liquid and vapour phases at equilibrium. The expanded uncertainties are approximated on average as T = 0.07 K, 0.008 MPa, and 0.007 and 0.009 for the temperature, pressure, and the liquid and vapour mole fractions, respectively. A homogenous maximum-pressure azeotrope was observed for both binary systems at all temperatures studied. The experimental data were correlated with the Peng–Robinson equation of state using the Mathias–Copeman alpha function, paired with the Wong–Sandler mixing rule and the Non-Random Two Liquid activity coefficient model. The model provided satisfactory representation of the phase equilibrium data measured
International Nuclear Information System (INIS)
(Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of {water (1) + phosphoric acid (2) + organic solvents (3)} were determined at T = 298.2 K and atmospheric pressure. The organic solvents were cyclohexane, 2-methyl-2-butanol (tert-amyl alcohol), and isobutyl acetate. All the investigated systems exhibit Type-1 behaviour of LLE. The immiscibility region was found to be larger for the (water + phosphoric acid + cyclohexane) ternary system. The experimental LLE results were correlated with the NRTL model, and the binary interaction parameters were obtained. The reliability of the experimental tie-line results was tested through the Othmer-Tobias and Bachman correlation equations. Distribution coefficients and separation factors were evaluated over the immiscibility regions and a comparison of the extracting capabilities of the solvents was made with respect to these factors. The experimental results indicate the superiority of cyclohexane as the preferred solvent for the extraction of phosphoric acid from its aqueous solutions.
Energy Technology Data Exchange (ETDEWEB)
Ghanadzadeh, H., E-mail: hggilani@guilan.ac.i [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of); Department of Chemical Engineering, University of Guilan, Rasht (Iran, Islamic Republic of); Ghanadzadeh, A., E-mail: aggilani@guilan.ac.i [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of); Aghajani, Z.; Abbasnejad, S.; Shekarsaraee, S. [Department of Chemistry, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of)
2010-06-15
(Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of left bracewater (1) + phosphoric acid (2) + organic solvents (3)right brace were determined at T = 298.2 K and atmospheric pressure. The organic solvents were cyclohexane, 2-methyl-2-butanol (tert-amyl alcohol), and isobutyl acetate. All the investigated systems exhibit Type-1 behaviour of LLE. The immiscibility region was found to be larger for the (water + phosphoric acid + cyclohexane) ternary system. The experimental LLE results were correlated with the NRTL model, and the binary interaction parameters were obtained. The reliability of the experimental tie-line results was tested through the Othmer-Tobias and Bachman correlation equations. Distribution coefficients and separation factors were evaluated over the immiscibility regions and a comparison of the extracting capabilities of the solvents was made with respect to these factors. The experimental results indicate the superiority of cyclohexane as the preferred solvent for the extraction of phosphoric acid from its aqueous solutions.
Synergism and Combinatorial Coding for Binary Odor Mixture Perception in Drosophila.
Kundu, Srikanya; Ganguly, Anindya; Chakraborty, Tuhin Subhra; Kumar, Arun; Siddiqi, Obaid
2016-01-01
Most odors in the natural environment are mixtures of several compounds. Olfactory receptors housed in the olfactory sensory neurons detect these odors and transmit the information to the brain, leading to decision-making. But whether the olfactory system detects the ingredients of a mixture separately or treats mixtures as different entities is not well understood. Using Drosophila melanogaster as a model system, we have demonstrated that fruit flies perceive binary odor mixtures in a manner that is heavily dependent on both the proportion and the degree of dilution of the components, suggesting a combinatorial coding at the peripheral level. This coding strategy appears to be receptor specific and is independent of interneuronal interactions. PMID:27588303
International Nuclear Information System (INIS)
This work presents a simple, rapid, and novel method for simultaneous determination of binary mixtures of some surfactants using continuous wavelet transformation. The method is based on the difference in the effect of surfactants Cetyltrimethylammoniumbromide (CTAB), dodecyl trimethylammonium bromide (DTAB), cetylpyridinium bromide (CPB) and TritonX-100 (TX-100) on the absorption spectra of complex of Beryllium with Chrome Azurol S (CAS) at pH 5.4. Binary mixtures of CTAB-DTAB, DTAB-CPB and CTAB-TX-100 were analyzed without prior separation steps. Different mother wavelets from the family of continuous wavelet transforms were selected and applied under the optimal conditions for simultaneous determinations. The proposed methods, under the working conditions, were successfully applied to simultaneous determination of surfactants in hair conditioner and mouthwash samples.
Effects of a temperature-dependent viscosity on thermal convection in binary mixtures
Hilt, Markus; Glässl, Martin; Zimmermann, Walter
2014-05-01
We investigate the effect of a temperature-dependent viscosity on the onset of thermal convection in a horizontal layer of a binary fluid mixture that is heated from below. For an exponential temperature dependence of the viscosity, we find, in binary mixtures as a function of a positive separation ratio ψ and beyond a certain viscosity contrast, a discontinuous transition between two stationary convection modes having different wavelengths. In the range of negative values of the separation ratio ψ, a (continuous or discontinuous) transition from an oscillatory to a stationary onset of convection occurs beyond a certain viscosity contrast, and for large values of the viscosity ratio, the oscillatory onset of convection is suppressed.
Excess molar enthalpies for binary mixtures of different amines with water
International Nuclear Information System (INIS)
Highlights: • Isothermal excess molar enthalpies for binary mixtures of different amines with water. • The Redlich–Kister equation and the NRTL model was used to fit the experimental data. • The excess molar enthalpies were discussed with different structures of amines. - Abstract: The isothermal excess molar enthalpies for binary mixtures of different amines with water were measured with a C-80 Setaram calorimeter. The experimental results indicate that the excess molar enthalpy is related to the molecular structure. The experimental excess molar enthalpies were satisfactorily fitted with the Redlich–Kister equation. They were also used to test the suitability of the NRTL model, and the deviations are a little larger than the R–K equation
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.
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.
International Nuclear Information System (INIS)
Graphical abstract: Osmotic properties of binary mixture of two ionic liquids (ILs): 1-butyl-1-methyl pyrrolidinium dicyanamide and 1-methyl-3-octylimidazolium chloride with water was reported by using vapour pressure osmometry (VPO) method. - Highlights: • Osmotic properties of binary mixture of ionic liquids (ILs) with water by using vapour pressure osmometry (VPO) method. • The experimental osmotic coefficients were well correlated by Archer extension of Pitzer model. • From the experimental osmotic coefficient data the critical micellar concentration (cmc) of the ILs in water was estimated. • Mean molar activity coefficient and the excess Gibbs free energy was determine for the (ILs + water) binary mixture. - Abstract: In this work, the osmotic properties of the binary mixture of ionic liquids (ILs) and water were studied by using vapour pressure osmometry (VPO) method. We have used two ILs: 1-butyl-1-methyl pyrrolidinium dicyanamide and 1-methyl-3-octylimidazolium chloride. The aqueous solution of NaCl was used as the reference solution to precisely measure the osmotic coefficients of the above systems. We have calculated the activity of water in the above systems and the change of vapour pressure of water due to the addition of ILs in water. The experimental osmotic coefficients were correlated by the Archer extension of Pitzer model. The parameters of this Archer extension of Pitzer model were found from this data fitting. From the experimental osmotic coefficient value we have estimated the critical micellar concentration (cmc) of ILs in water. The experimental values of osmotic coefficient in the above systems were compared with the literature and the reason of variation was explained, in terms of the aggregation of ILs in water
Steam oxidation of boron carbide–stainless steel liquid mixtures
International Nuclear Information System (INIS)
In the framework of nuclear reactor core meltdown accidents studies, the oxidation kinetics of boron carbide–stainless steel liquid mixtures exposed to argon/steam atmospheres was investigated at temperatures up to 1527 °C. A B–Cr–Si–O liquid protective layer forms on the surface of the mixtures in contact with steam. This protective layer gradually transforms into a Cr2O3-rich slag. Important quantities of liquid can be projected from the melt during oxidation. These projections are favoured by high B4C contents in the melt, high steam partial pressures and low temperatures. In addition to stainless steel–boron carbide melts, simpler compositions (pure 304L stainless steel, iron–boron, iron–boron carbide and stainless steel–boron) were studied, in order to identify the basic oxidation mechanisms.
Attractive Interaction Between Pulses in a Model for Binary-Mixture Convection
Riecke, H
1995-01-01
Recent experiments on convection in binary mixtures have shown that the interaction between localized waves (pulses) can be repulsive as well as {\\it attractive} and depends strongly on the relative {\\it orientation} of the pulses. It is demonstrated that the concentration mode, which is characteristic of the extended Ginzburg-Landau equations introduced recently, allows a natural understanding of that result. Within the standard complex Ginzburg-Landau equation this would not be possible.
Structure formation in binary mixtures of lipids and detergents: Self-assembly and vesicle division
Noguchi, Hiroshi
2012-01-01
Self-assembly dynamics in binary surfactant mixtures and structure changes of lipid vesicles induced by detergent solution are studied using coarse-grained molecular simulations. Disk-shaped micelles, the bicelles, are stabilized by detergents surrounding the rim of a bilayer disk of lipids. The self-assembled bicelles are considerably smaller than bicelles formed from vesicle rupture, and their size is determined by the concentrations of lipids and detergents and the interactions between the...
Uphill diffusion and overshooting in the adsorption of binary mixtures in nanoporous solids
Lauerer, Alexander; Binder, Tomas; Chmelik, Christian; Miersemann, Erich; Haase, Jürgen; Ruthven, Douglas M.; Kärger, Jörg
2015-01-01
Under certain conditions, during binary mixture adsorption in nanoporous hosts, the concentration of one component may temporarily exceed its equilibrium value. This implies that, in contrast to Fick's Law, molecules must diffuse in the direction of increasing rather than decreasing concentration. Although this phenomenon of ‘overshooting' has been observed previously, it is only recently, using microimaging techniques, that diffusive fluxes in the interior of nanoporous materials have become...
Thiele, Uwe; Madruga Sánchez, Santiago; 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 subs...
Lattice Boltzmann simulations of segregating binary fluid mixtures in shear flow
Lamura, A.; Gonnella, G.
2000-01-01
We apply lattice Boltzmann method to study the phase separation of a two-dimensional binary fluid mixture in shear flow. The algorithm can simulate systems described by the Navier-Stokes and convection-diffusion equations. We propose a new scheme for imposing the shear flow which has the advantage of preserving mass and momentum conservation on the boundary walls without introducing slip velocities. Our main results concern the presence of two typical lenght scales in the phase separation pro...
Spinodal decomposition of a binary mixture in an uniform shear flow
Corberi, F.; Gonnella, G.; Lamura, A.
1998-01-01
Results are presented for the phase separation process of a binary mixture subject to an uniform shear flow quenched from a disordered to a homogeneous ordered phase. The kinetics of the process is described in the context of the time-dependent Ginzburg-Landau equation with an external velocity term. The one-loop approximation is used to study the evolution of the model. We show that the structure factor obeys a generalized dynamical scaling. The domains grow with different typical lengthscal...
Maninder Kumar; V. K. Rattan
2013-01-01
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 equati...
Mass-dependence of self-diffusion coefficients in disparate-mass binary fluid mixtures
I. Binas; I.Mryglod
2009-01-01
Self-diffusion coefficients of a binary fluid mixture with components differing only in their particle masses are studied, in particular the case when mass ratio μ of light and heavy particles tends to zero. These coefficients were calculated within the memory function formalism, using the systematic subsequence of approximations for the relaxation times of velocity autocorrelation function. We obtained a general relation for the self-diffusion coefficients which show polynomial dependence on...
Energy Technology Data Exchange (ETDEWEB)
Mekki, Ahmed [Ecole Militaire Polytechnique EMP, BP 17 Bordj-El-Bahri, Alger (Algeria); Khimeche, Kamel, E-mail: kamel.khimeche@yahoo.f [Ecole Militaire Polytechnique EMP, BP 17 Bordj-El-Bahri, Alger (Algeria); Dahmani, Abdallah [Laboratoire de thermodynamique et modelisation moleculaire, Faculte de chimie, USTHB, BP. 32 El-Alia, 1611 Bab-Ezzouar, Alger (Algeria)
2010-08-15
A differential scanning calorimetry (d.s.c.) was used to determine binary (solid + liquid) phase equilibria (SLE) for four binary mixtures, viz. (n-nitrosodiphenylamine + diphenylamine), (2-nitrodiphenylamine + ethyl centralite), (2,4-dinitro-N-ethylaniline + methyl centralite), and (2,4-diphenylamine + 4,4'-dinitroethylcentralite). These compounds are used as stabilizers in gun powders and propellants. Results obtained with this technique are compared with those correlated by NRTL and ideal models. It was found out that all the systems are simple eutectic systems and deviations between experimental and predicted SLE results were observed.
Smectic, nematic, and isotropic phases in binary mixtures of thin and thick hard spherocylinders.
Cinacchi, Giorgio; Martínez-Ratón, Yuri; Mederos, Luis; Velasco, Enrique
2006-06-21
A second-virial Onsager theory, based on Parsons-Lee rescaling and suitably extended to deal with multicomponent systems and smectic phases, has been used to calculate the phase diagram of a collection of binary mixtures of thin and thick hard spherocylinders. In particular, two types of phase diagrams are investigated. First, a number of binary mixtures where the two components have the same total length have been considered; in addition, the phase diagram of a binary mixture where the two components have the same volume has been calculated. For the particles of one of the two components, the length of the cylindrical part and the diameter have always been set equal to 5 and 1, respectively. Spherocylinders of the same total length and different diameter tend to demix considerably as soon as the diameter ratio deviates from unity. This happens especially at high pressures, when at least the phase richer in the thicker component is smectic. In the case where the two components have equal volumes, demixing is further increased due to the disparity not only in particle diameter but also in particle lengths. The incorporation of inhomogeneous layered phases is seen to alter significantly the phase diagrams calculated if only homogeneous phases are allowed, since transitions to a smectic phase often preempt those to a nematic or an isotropic phase. The apparent versatility of the recent experimental techniques suggests that the phase diagram features predicted by the theory might be also observed in real systems. PMID:16821950
Picosecond solvation dynamics—A potential viewer of DMSO—Water binary mixtures
Banik, Debasis; Kundu, Niloy; Kuchlyan, Jagannath; Roy, Arpita; Banerjee, Chiranjib; Ghosh, Surajit; Sarkar, Nilmoni
2015-02-01
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 XD = 0.12-0.17 and XD = 0.27-0.35, respectively. Among them, the second region (XD = 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:2H2O complexes, hydration around the probe C480 decreases, as a result of which solvation time increases.
Energy Technology Data Exchange (ETDEWEB)
Ploetz, Elizabeth A.; Smith, Paul E. [Department of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas 66506 (United States)
2015-03-07
Kirkwood-Buff or Fluctuation Solution Theory can be used to provide experimental pair fluctuations, and/or integrals over the pair distribution functions, from experimental thermodynamic data on liquid mixtures. Here, this type of approach is used to provide triplet and quadruplet fluctuations, and the corresponding integrals over the triplet and quadruplet distribution functions, in a purely thermodynamic manner that avoids the use of structure factors. The approach is then applied to binary mixtures of water + methanol and benzene + methanol over the full composition range under ambient conditions. The observed correlations between the different species vary significantly with composition. The magnitude of the fluctuations and integrals appears to increase as the number of the most polar molecule involved in the fluctuation or integral also increases. A simple physical picture of the fluctuations is provided to help rationalize some of these variations.
Dielectric properties of liquid systems: the ideal complex permittivity in liquid mixtures
Adrián H. Buep
2009-01-01
A general definition for ideal complex permittivity in a liquid mixture was reached by considering a thermodynamically ideal mixture under the effect of an applied harmonic electric field. The resulting definition is independent of any particular dielectric model, as well as the polarity of the components.
Composition and thermal analysis of binary mixtures of mee fat and palm stearin.
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. PMID:24671022
Son, Jino; Lee, Yun-Sik; Kim, Yongeun; Shin, Key-Il; Hyun, Seunghun; Cho, Kijong
2016-10-01
The joint toxic effects of binary metal mixtures of copper (Cu), manganese (Mn) and nickel (Ni) on reproduction of Paronhchiurus kimi (Lee) was evaluated using a toxic unit (TU) approach by judging additivity across a range of effect levels (10-90%). For all metal mixtures, the joint toxic effects of metal mixtures on reproduction of P. kimi decreased in a TU-dependent manner. The joint toxic effects of metal mixtures also changed from less than additive to more than additive at an effect level lower than or equal to 50%, while a more than additive toxic effects were apparent at higher effect levels. These results indicate that the joint toxicity of metal mixtures is substantially different from that of individual metals based on additivity. Moreover, the close relationship of toxicity to effect level suggests that it is necessary to encompass a whole range of effect levels rather than a specific effect level when judging mixture toxicity. In conclusion, the less than additive toxicity at low effect levels suggests that the additivity assumption is sufficiently conservative to warrant predicting joint toxicity of metal mixtures, which may give an additional margin of safety when setting soil quality standards for ecological risk assessment. PMID:27318557
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. PMID:26971405
The effects of binary UV filter mixtures on the midge Chironomus riparius.
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. PMID:26971216
Bhatia, Subhash C.; Sangwan, Jasbir; Rani, Ruman; Kiran, Vijay
2013-11-01
Densities, , viscosities, , speeds of sound, , and refractive indices, , of binary liquid mixtures of 2-ethyl-1-hexanol with benzene, chlorobenzene, and bromobenzene have been measured over the entire range of composition at 298.15 K, 303.15 K, and 308.15 K and at atmospheric pressure. From the experimental data of the density, speed of sound, viscosity, and refractive index, the values of the excess molar volume, , isentropic compressibility, , and deviations in molar refraction, , have been calculated. The viscosity data have been correlated using McAllister's three-body interaction model at different temperatures. The calculated excess and deviation functions have been analyzed in terms of molecular interactions and structural effects.
Bhatia, Subhash C.; Rani, Ruman; Sangwan, Jasbir; Bhatia, Rachna
2011-06-01
Densities, ρ, viscosities, η, speeds of sound, u, and refractive indices, n D, of binary liquid mixtures of 1-decanol with o-chlorotoluene, m-chlorotoluene, and p-chlorotoluene have been measured over the entire range of composition at 298.15 K, 303.15 K, and 308.15 K and at atmospheric pressure. From the experimental data of density, speed of sound, viscosity and refractive index, the values of the excess molar volume, V E, deviations in isentropic compressibility, Δ κ S , and deviations in molar refraction, Δ R, have been calculated. The calculated excess and deviation functions have been analyzed in terms of molecular interactions and structural effects.
Habibullah, M.; Das, Kamalendra N.; Rahman, Ismail M. M.; Uddin, M. Ashraf; Saifuddin, Khaled; Iwakabe, Koichi; Hasegawa, Hiroshi
2010-01-01
Densities and viscosities of binary liquid mixtures of hexan-1-ol + o-xylene, + m-xylene, or + p-xylene were measured at a number of mole fractions at T = (308.15 and 318.15) K and atmospheric pressure. The excess volumes and the viscosity deviations from the mole fraction average were calculated from the experimental density and viscosity data. The experimental data were correlated with Redlich-Kister equation. Variations in the calculated excess and deviation properties for the liquid mixtu...
Critical behavior of nanoparticle-containing binary liquid mixtures
Czech Academy of Sciences Publication Activity Database
Štěpánek, Petr; Bakaeva, Zulfiya; Černoch, Peter; Nallet, F.; Noirez, L.
Pisa : European Polymer Federation, 2013. O2-54. [European Polymer Congress - EPF 2013. 16.06.2013-21.06.2013, Pisa] R&D Projects: GA ČR GA202/09/2078 Institutional support: RVO:61389013 Keywords : nanoparticles * hydrogen bonds Subject RIV: BO - Biophysics
Critical behavior of nanoparticle-containing binary liquid mixtures
Czech Academy of Sciences Publication Activity Database
Bakaeva, Zulfiya; Černoch, Peter; Štěpánek, Petr; Nallet, F.; Noirez, L.
2013-01-01
Roč. 15, č. 16 (2013), s. 5831-5835. ISSN 1463-9076 R&D Projects: GA ČR GA202/09/2078 Institutional research plan: CEZ:AV0Z40500505 Keywords : small angle neutron scattering * critical fluctuations * Ginzburg number Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.198, year: 2013
In Chul Kong
2014-01-01
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 m...
Semi-empirical modeling of pool boiling heat transfer in binary mixtures
International Nuclear Information System (INIS)
Highlights: • The boiling heat transfer coefficient of mixtures are less than those of ideal. • Evaporation of the volatile component increases the V–L interfacial temperature. • The transition q/A from free convection to boiling is about 20 kW per square meter. -- Abstract: Pool boiling heat transfer has been investigated for various binary mixtures, including acetone/isopropanol, water/acetone, water/methanol, water/ethanol, water/isopropanol, water/monoethanolamine, water/diethanolamine and water/triethyleneglycol as test solutions. Many correlations have been developed to predict the pool boiling heat transfer coefficient in mixtures in the past few decades, however the predicted values are not confirming. In addition, the application of many existing correlations requires some individual adjusting parameters that may be not available for every system. In this investigation, a new set of experimental data are presented. These data have been compared to major existing correlations. It is observed that the pool boiling heat transfer coefficients in mixtures are less than the ideal boiling heat transfer coefficient. A new semi-empirical model has been proposed based on the mass transfer resistance to predict the boiling heat transfer coefficient with satisfactory accuracy. The new model does not include any tuning parameter and is applicable to any given binary system. The performance of the proposed model is superior to most existing correlations
Photosensitive soft matter: mixtures of nematic liquid crystal with azo molecules
International Nuclear Information System (INIS)
Photosensitive soft matter based upon guest-host liquid crystal systems was prepared by mixing azobenzene-containing mesogens with the nematic liquid crystal 4-butyl-cyclohexane carboxylic acid 4-pentyloxy-phenyl ester (CM80). Binary mixtures of the host CM80 with three azo-bonded compounds as UV-active dopants (guests) at a relatively small concentration of 1~wt.% were characterized by thermo-optical, dielectric, spectral and flexoelectric measurements. The study aimed to determine the mechanisms that result in variations of material parameters caused by light-driven molecular conformation change of the azo-dye guest molecules (the transition from rod-shaped trans isomers to bent-shaped cis isomers)
International Nuclear Information System (INIS)
Highlights: • A DSC calorimeter for measuring (solid + liquid) phase equilibrium and heat capacities is presented. • (Diphenyl ether + biphenyl) system presents a eutectic (solid + liquid) phase diagram with complete immiscibility in solid phase. • The T, x conditions of the eutectic point are x = (0.705 and 285.6) K, while 93.2 J · g−1 · K−1 is the latent heat of fusion. • The Wilson and NRTL equations, and the predictive UNIFAC model describes adequately the solid liquid phase equilibrium data. • The system exhibits high and positive excess heat capacities which can be correlated by using a Redlich–Kister equation. - Abstract: The (solid + liquid) phase equilibrium for eight {x diphenyl ether + (1 − x) biphenyl} binary mixtures, including the eutectic mixture were studied by using a differential scanning calorimetry (DSC) technique. A good agreement was found between previous literature and experimental values here presented for the melting point and enthalpy of fusion of pure compounds. The well-known equations for Wilson and the non-random two-liquid (NRTL) were used to correlate experimental solid liquid phase equilibrium data. Moreover, the predictive mixture model UNIFAC has been employed to describe the phase diagram. With the aim to check this equipment to measure heat capacities in the quasi-isothermal Temperature-Modulated Differential Scanning Calorimetry method (TMDSC), four fluids of well-known heat capacity such as toluene, n-decane, cyclohexane and water were also studied in the liquid phase at temperatures ranging from (273.15 to 373.15) K. A good agreement with literature values was found for those fluids of pure diphenyl ether and biphenyl. Additionally, the specific isobaric heat capacities of diphenyl ether and biphenyl binary mixtures in the liquid phase up to T = 373.15 K were measured
Intense Infrared Scintillation of Liquid Ar-Xe Mixtures
Neumeier, A; Heindl, T; Himpsl, A; Hagn, H; Hofmann, M; Oberauer, L; Potzel, W; Roth, S; Schönert, S; Wieser, J; Ulrich, A
2015-01-01
Intense infrared (IR) light emission from liquid Ar-Xe mixtures has been observed using 12 keV electron-beam excitation. The emission peaks at a wavelength of 1.18 $\\mu$m and the half-width of the emission band is 0.1 $\\mu$m. Maximum intensity has been found for a 10 ppm xenon admixture in liquid argon. The conversion efficiency of electron beam-power to IR-light is about 1% (10000 photons per MeV electron energy deposited). A possible application of this intense IR emission for a new particle discrimination concept in liquid noble gas detectors is discussed. No light emission was found for perfectly purified liquid argon in the wavelength range from 0.5 to 3.5 $\\mu$m on the current level of sensitivity.
International Nuclear Information System (INIS)
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-ethylpyridinium ethylsulfate were determined at T = 323.15 K using the vapour pressure osmometry technique. From the experimental results, vapour pressure and activity coefficients can be determined. For the correlation of osmotic coefficients, the extended Pitzer model modified by Archer, and the modified NRTL (MNRTL) model were used, obtaining deviations lower than 0.017 and 0.047, respectively. The mean molal activity coefficients and the excess Gibbs free energy for the binary mixtures studied were determined from the parameters obtained with the extended Pitzer model modified by Archer.
Topological investigations of thermodynamic properties of binary mixtures containing 2-pyrrolidinone
International Nuclear Information System (INIS)
Excess molar volumes, VmE, excess molar enthalpies, HmE, and speeds of sound data, u, of 2-pyrrolidinone (i) + benzene or toluene or o- or p- or m-xylene (j) binary mixtures have been measured as a function of composition at 308.15 K. Isentropic compressibility changes of mixing, κSE have been determined by employing speeds of sound data. The observed data have been estimated by employing Graph theory (which involves topology of the constituents of the mixtures). It has been observed that VmE, HmE and κSE values predicted by Graph theory compare well with their corresponding experimental values. IR studies lend further credence to the nature and extent of interaction of the proposed structures of molecular species in these mixtures.
de las Heras, Daniel; Schmidt, Matthias
2015-05-01
We give a full account of a recently proposed theory that explicitly relates the bulk phase diagram of a binary colloidal mixture to its phase stacking phenomenology under gravity (de las Heras and Schmidt 2013 Soft Matter 9 8636). As we demonstrate, the full set of possible phase stacking sequences in sedimentation-diffusion equilibrium originates from straight lines (sedimentation paths) in the chemical potential representation of the bulk phase diagram. From the analysis of various standard topologies of bulk phase diagrams, we conclude that the corresponding sedimentation stacking diagrams can be very rich, even more so when finite sample height is taken into account. We apply the theory to obtain the stacking diagram of a mixture of nonadsorbing polymers and colloids. We also present a catalog of generic phase diagrams in the plane of chemical potentials in order to facilitate the practical application of our concept, which also generalizes to multi-component mixtures.
Measurement of thermodiffusion coefficient in n-alkane binary mixtures: composition dependence.
Madariaga, J A; Santamaría, C; Bou-Ali, M Mounir; Urteaga, P; Alonso De Mezquia, D
2010-05-27
In this work, we have measured the thermodiffusion coefficient of different n-alkane binary mixtures at several concentrations using the thermogravitational technique. In particular, we have studied the n-dodecane/n-heptane system as a function of composition and other systems covering a large range of mass differences and concentration at 25 degrees C and 1 atm. The results show that for any concentration the thermodiffusion coefficient of n-alkane mixtures is proportional to the mass difference between the components and to the ratio of the thermal expansion coefficient and viscosity of the mixture. The obtained equation allows us to determine the infinite dilution values of the thermodiffusion coefficient. We compare these values with recent experimental results in dilute polymer solutions and analyze the Brenner theory of thermodiffusion. Finally, it is shown that the thermodiffusion coefficient depends linearly with the mass fraction, and it can be calculated from the viscosity and thermal expansion of the pure components. PMID:20429569
Shirota, Hideaki; Biswas, Ranjit
2012-11-26
We report here the low-frequency spectra, resulting from the intermolecular/interionic vibrational dynamics, of aqueous mixtures of an ionic liquid, 1-methyl-3-n-octylimidazolium tetrafluoroborate, with the H(2)O mole fractions of 0.2, 0.4, and 0.6 and the neat ionic liquid and H(2)O within the frequency range of 0.1-700 cm(-1) by means of femtosecond Raman-induced Kerr effect spectroscopy. Addition of H(2)O induces tiny effects on the line shape of the low-frequency Kerr spectrum of the ionic liquid: ca. a 2 cm(-1) red shift in the first moment of the low-frequency spectrum has been observed for a transition from the neat ionic liquid to the binary mixture containing 0.6 mol fraction of H(2)O. Surface tension and liquid density of the mixture also accompany minimal changes upon addition of H(2)O. These results suggest that H(2)O molecules localize at the interface between the ionic and nonpolar regions, and the interionic interaction in the ionic region is weakly perturbed by the existence of H(2)O. On the other hand, successive addition of H(2)O in the mixture slows down the picosecond overdamped relaxation process measured in the 3-300 ps range even though the shear viscosity of the mixture decreases substantially. PMID:23148797
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).
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.
Electron swarm and transport coefficients for the binary mixtures of SF6 with Ar and Xe
International Nuclear Information System (INIS)
A pulsed Townsend technique was used to measure the electron drift velocity, the longitudinal diffusion, and the effective ionization coefficients, and the limiting field strength for the binary mixtures of SF6 with Ar and Xe. This paper covered a wide range of the density-reduced electric field strength E/N between 50 and 700 Td (1 Townsend (Td) = 10-17 V cm2). The content of SF6 in the gas mixtures was varied over the range 1-90%. For the SF6-Ar mixture, the electron drift velocities were found to be higher than those for pure SF6, and conversely for the SF6-Xe mixture. The above can be explained in terms of the larger momentum transfer cross-section for electrons in Xe than in Ar. The limiting field strength for the SF6-Xe mixture was found to be higher than that for the SF6-Ar one, but still lower than that for the SF6-N2 mixture
Ali, A.; Nabi, F.; Tariq, M.
2009-04-01
The densities, ρ, viscosities, η, ultrasonic speeds, u, and refractive indices, n D, of pure benzene, methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), styrene (STY), and their binary liquid mixtures have been measured over the entire composition range at 298.15 K, 303.15 K, 308.15 K, and 313.15 K. The experimental data have been used to calculate excess molar volumes. Partial molar volumes of MA/EA/BA/STY in benzene at infinite dilution and at different temperatures have also been evaluated. The results were discussed in terms of molecular interactions prevailing in the mixtures.
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.
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.
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)
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.
Thermal diffusion segregation in granular binary mixtures described by the Enskog equation
Energy Technology Data Exchange (ETDEWEB)
Garzo, Vicente, E-mail: vicenteg@unex.es [Departamento de Fisica, Universidad de Extremadura, E-06071 Badajoz (Spain)
2011-05-15
The diffusion induced by a thermal gradient in a granular binary mixture is analyzed here in the context of the (inelastic) Enskog equation. Although the Enskog equation neglects velocity correlations among particles that are about to collide, it retains the spatial correlations arising from volume exclusion effects and thus is expected to be applicable for moderate densities. In the steady state with gradients only along a given direction, a segregation criterion is obtained from the thermal diffusion factor {Lambda} by measuring the amount of segregation parallel to the thermal gradient. As expected, the sign of the factor {Lambda} provides a criterion for the transition between the Brazil-nut effect (BNE) and the reverse Brazil-nut effect (RBNE) by varying the parameters of the mixture (the masses and sizes of particles, concentration, solid volume fraction and coefficients of restitution). The form of the phase diagrams for the BNE/RBNE transition is illustrated in detail for several systems, with special emphasis on the significant role played by the inelasticity of collisions. In particular, an effect already found in dilute gases (segregation in a binary mixture of identical masses and sizes but different coefficients of restitution) is extended to dense systems. A comparison with recent computer simulation results reveals good qualitative agreement at the level of the thermal diffusion factor. The present analysis generalizes to arbitrary concentration previous theoretical results derived in the tracer limit case.
Relative permittivity data of binary mixtures containing 2-butanol, 2-butanone, and cyclohexane
International Nuclear Information System (INIS)
Research highlights: → Kirkwood g factor values indicate parallel dipole association for s-BuOH and MEK. → Heterogeneous interactions are dominant in (s-BuOH + MEK) mixtures. → Mixing rules predict permittivity of s-BuOH and MEK in nonpolar media acceptably. - Abstract: Relative permittivity measurements were made on binary mixtures of (2-butanol + 2-butanone) and (2-butanol or 2-butanone + cyclohexane) for various concentrations at T = (298.2, 308.2, and 318.2) K. Some experimental results are compared with those obtained from theoretical calculations and interpreted in terms of homo- and heterogeneous interactions and structural effects. The molecular dipole moments were determined using Guggenheim-Debye method within the temperature range of (298.2 to 318.2) K. The variations of effective dipole moment and correlation factor, g, with the mole fraction in these materials were investigated using Kirkwood-Frohlich equation. The pure compounds showed a negative and small temperature coefficient of effective dipole moment. In order to obtain valuable information about heterogeneous interaction (interactions between the unlike molecules), the Kirkwood correlation factor, the Bruggeman dielectric factor and the excess permittivity were calculated. In order to predict the permittivity data of polar-apolar binary mixtures, five mixing rules were applied.
Toxicity of binary mixtures of oil fractions to sea urchin embryos.
Rial, Diego; Vázquez, José A; Menduiña, Araceli; García, Ana M; González, M Pilar; Mirón, Jesús; Murado, Miguel A
2013-12-15
The assumption of additive toxicity for oil compounds is related to a narcotic mode of action. However, the joint toxicity of oil fractions has not been fully investigated. A fractionation of Maya crude oil into aliphatics, aromatics and polars was performed, fractions were dissolved in dimethyl sulfoxide (DMSO) and subsequently toxicity of single fractions and binary mixtures was assessed using the sea urchin embryo test. The descriptive ability of Concentration Addition (CA), Independent Action (IA) and modifications of both models for describing the joint toxicity of mixtures has also been evaluated. The hydrocarbon content extractable with dichloromethane of the fractions dissolved in DMSO was: 12.0 ± 1.8 mg mL(-1), 39.0 ± 0.5 mg mL(-1) and 20.5 ± 2.5 mg mL(-1) for aliphatics, aromatics and polars, respectively. The toxicity of the extracts in DMSO of the fractions as EC50 (μLL(-1)) was: aliphatics (165.8-242.3)binary mixtures (aliphatics-aromatics, aromatics-polars) greater than the IA (aliphatics-polars) according to the Akaike Information Criterion, so CA was considered a better option than IA to explain the joint toxicity of oil fractions. In addition, synergistic or antagonistic effects were not observed. PMID:24231335
De Mezquia, D Alonso; Bou-Ali, M Mounir; Larrañaga, M; Madariaga, J A; Santamaría, C
2012-03-01
In this work we have measured the molecular diffusion coefficient of the n-alkane binary series nC(i)-nC(6), nC(i)-nC(10), and nC(i)-nC(12) at 298 K and 1 atm and a mass fraction of 0.5 by using the so-called sliding symmetric tubes technique. The results show that the diffusion coefficient at this concentration is proportional to the inverse viscosity of the mixture. In addition, we have also measured the diffusion coefficient of the systems nC(12)-nC(6), nC(12)-nC(7), and nC(12)-nC(8) as a function of concentration. From the data obtained, it is shown that the diffusion coefficient of the n-alkane binary mixtures at any concentration can be calculated from the molecular weight of the components and the dynamic viscosity of the corresponding mixture at 50% mass fraction. PMID:22263833
Lotfy, Hayam Mahmoud; Hegazy, Maha A; Rezk, Mamdouh R; Omran, Yasmin Rostom
2014-05-21
Two smart and novel spectrophotometric methods namely; absorbance subtraction (AS) and amplitude modulation (AM) were developed and validated for the determination of a binary mixture of timolol maleate (TIM) and dorzolamide hydrochloride (DOR) in presence of benzalkonium chloride without prior separation, using unified regression equation. Additionally, simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of the binary mixture namely; simultaneous ratio subtraction (SRS), ratio difference (RD), ratio subtraction (RS) coupled with extended ratio subtraction (EXRS), constant multiplication method (CM) and mean centering of ratio spectra (MCR). The proposed spectrophotometric procedures do not require any separation steps. Accuracy, precision and linearity ranges of the proposed methods were determined and the specificity was assessed by analyzing synthetic mixtures of both drugs. They were applied to their pharmaceutical formulation and the results obtained were statistically compared to that of a reported spectrophotometric method. The statistical comparison showed that there is no significant difference between the proposed methods and the reported one regarding both accuracy and precision. PMID:24607469
Lu, Shaohua; Zhang, Xin; Zhang, Zhuoyong; Yang, Yuping; Xiang, Yuhong
2016-11-15
Terahertz time domain spectroscopy (THz-TDS) combined with chemometrics has been utilized for the qualitative and quantitative analysis of binary mixtures of l-glutamic acid and l-glutamine which have similar chemical structures and properties. The binary mixtures of amino acids were prepared with yellow foxtail millet matrix, substituted for polyethylene (PE) as previously reported. After proper pretreatment of absorption spectra, quantitative analysis was achieved by partial least squares (PLS) and interval partial least squares (iPLS) regressions. The performance of models was evaluated based on the root mean square error of prediction (RMSEP) and correlation coefficient (R(2)) of cross-validations with bootstrapped Latin partitions as criterion. The iPLS yielded better results with low RMSEP (0.39±0.02%, 0.39±0.02%), and higher R(2) values (0.9904, 0.9906) for glutamine and glutamic acid comparing to the conventional PLS models. Multivariate curve resolution alternating least squares (MCR-ALS) was successfully applied for resolution of pure THz spectra and concentration profiles of two amino acids components from mixtures. PMID:27283659
Solubility of anthracene in binary alcohol + 3-methoxy-1-butanol solvent mixtures
Energy Technology Data Exchange (ETDEWEB)
McHale, M.E.R.; Horton, A.S.M.; Padilla, S.A.; Trufant, A.L.; Sancha, N.U. De La; Vela, E.; Powell, J.R.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1997-01-01
Experimental solubilities are reported for anthracene dissolved in ten binary mixtures containing 3-methoxy-1-butanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-methyl-1-butanol, 4-methyl-2-pentanol, 1-octanol, and 2-ethyl-1-hexanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the ten systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 0.4% and 0.5% for the combined NIBS/Redlich-Kister and modified Wilson equations, respectively.
Energy Technology Data Exchange (ETDEWEB)
Powell, J.R.; McHale, M.E.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1996-07-01
Experimental solubilities are reported for anthracene dissolved in 16 binary mixtures containing either 2-pentanol or 4-methyl-2-pentanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 1-octanol, 2-methyl-1-propanol and 3-methyl-1-butanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the 16 systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 0.3% and 0.5% for the combined NIBS/Redlich-Kister and modified Wilson equations, respectively.
Uphill diffusion and overshooting in the adsorption of binary mixtures in nanoporous solids
Lauerer, Alexander; Binder, Tomas; Chmelik, Christian; Miersemann, Erich; Haase, Jürgen; Ruthven, Douglas M.; Kärger, Jörg
2015-07-01
Under certain conditions, during binary mixture adsorption in nanoporous hosts, the concentration of one component may temporarily exceed its equilibrium value. This implies that, in contrast to Fick's Law, molecules must diffuse in the direction of increasing rather than decreasing concentration. Although this phenomenon of `overshooting' has been observed previously, it is only recently, using microimaging techniques, that diffusive fluxes in the interior of nanoporous materials have become accessible to direct observation. Here we report the application of interference microscopy to monitor `uphill' fluxes, covering the entire period of overshooting from initiation until final equilibration. It is shown that the evolution of the profiles can be adequately predicted from the single-component diffusivities together with the binary adsorption equilibrium data. The guest molecules studied (carbon dioxide, ethane and propene) and the host material (ZSM-58 or DDR) are of practical interest in relation to the development of kinetically selective adsorption separation processes.
Shirota, Hideaki; Castner, Edward W
2005-10-27
In this study, we address the following question about room-temperature ionic liquids (RTILs). Are the properties of a RTIL more dependent on the charges of the molecular ions or on the fact that the liquid is a complex mixture of two species, one or both of which are asymmetric? To address this question and to better understand the interactions and dynamics in RTILs, we have prepared the organic ionic liquid 1-methoxyethylpyridinium dicyanoamide (MOEPy(+)/DCA(-)) and compared this RTIL with the analogous isoelectronic binary solution, comprised of equal parts of 1-methoxyethylbenzene (MOEBz) and dicyanomethane (DCM). In essence, we have created a RTIL and a nearly identical neutral pair in which we have effectively turned off the charges. To understand the intermolecular interactions in both of these liquids, we have characterized the bulk density and shear viscosity. Using femtosecond optical Kerr effect spectroscopy, we have also characterized the intermolecular vibrational dynamics and diffusive reorientation. To verify that the shape, polarizability, and electronic structure of the RTIL ions and the components of the neutral pair are truly quite similar, we have carried out density functional theory calculations on the individual molecular ion and neutral species. PMID:16866386
Toxicity of binary mixtures of metal oxide nanoparticles to Nitrosomonas europaea.
Yu, Ran; Wu, Junkang; Liu, Meiting; Zhu, Guangcan; Chen, Lianghui; Chang, Yan; Lu, Huijie
2016-06-01
Although the widely used metal oxide nanoparticles (NPs) titanium dioxide NPs (n-TiO2), cerium dioxide NPs (n-CeO2), and zinc oxide NPs (n-ZnO) have been well known for their potential cytotoxicities to environmental organisms, their combined effects have seldom been investigated. In this study, the short-term binary effect of n-CeO2 and n-TiO2 or n-ZnO on a model ammonia oxidizing bacterium, Nitrosomonas europaea were evaluated based on the examinations of cells' physiological, metabolic, and transcriptional responses. The addition of n-TiO2 mitigated the negative effect of more toxic n-CeO2 and the binary toxicity (antagonistic toxicity) of n-TiO2 and n-CeO2 was generally lower than the single NPs induced one. While the n-CeO2/n-ZnO mixture exerted higher cytotoxicity (synergistic cytotoxicity) than that from single NPs. The increased addition of the less toxic n-CeO2 exaggerated the binary toxicity of n-CeO2/n-ZnO mixture although the solubility of n-ZnO was not significantly affected, which excluded the contribution of the dissolved Zn ions to the enhancement of the combined cytotoxicity. The cell membrane disturbances and NP internalizations were detected for all the NP impacted cultures and the electrostatic interactions among the two distinct NPs and the cells were expected to play a key role in mediating their direct contacts and the eventual binary nanotoxicity to the cells. PMID:27016814
Staal, Y.C.M.; Hebels, D.G.A.J.; Herwijnen, M.H.M. van; Gottschalk, R.W.H.; Schooten, F.J. van; Delft, J.H.M. van
2007-01-01
Polycyclic aromatic hydrocarbons (PAHs) cover a wide range of structurally related compounds which differ greatly in their carcinogenic potency. PAH exposure usually occurs through mixtures rather than individual compounds. Therefore, we assessed whether the effects of binary PAH mixtures on gene ex
Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT
DEFF Research Database (Denmark)
Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios
2004-01-01
concentration coexistence curves at fixed pressure and temperature. The algorithms automatically trace the entire liquid-liquid coexistence curves in steps by adjusting the step size, generating initial estimates, and subsequently solving the phase-equilibrium problem by a second-order method. The algorithms...... are used for investigating the correlative and predictive capabilities of the thermodynamic model PC-SAFT. The investigation shows that the model correlates well experimental LLE data for binary as well as ternary systems but further predicts the behavior of the ternary systems with reasonably good...
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.
Picosecond solvation dynamics--a potential viewer of DMSO-water binary mixtures.
Banik, Debasis; Kundu, Niloy; Kuchlyan, Jagannath; Roy, Arpita; Banerjee, Chiranjib; Ghosh, Surajit; Sarkar, Nilmoni
2015-02-01
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 XD = 0.12-0.17 and XD = 0.27-0.35, respectively. Among them, the second region (XD = 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:2H2O complexes, hydration around the probe C480 decreases, as a result of which solvation time increases. PMID:25662652
Banerjee, Saikat; Bagchi, Biman
2013-10-01
In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tert-butyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures.
Further Studies of the Spur Process of Positronium Formation in Mixtures of Organic Liquids
DEFF Research Database (Denmark)
Jansen, P.; Mogensen, O. E.
1977-01-01
To test some predictions of the spur model of positronium (Ps) formation, positron lifetime studies were made of the following binary organic mixtures: (a) carbondisulphide mixtures with n-tetradecane, n-hexane, isooctane, neopentane, and tetramethylsilane (TMS); (b) neopentane mixtures with...
International Nuclear Information System (INIS)
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
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.
International Nuclear Information System (INIS)
The polarographic behaviour of simple solutions of selenite and tellurite in 1 M ammonium salts of formate, acetate, tartrate, oxalate, and benzoate solutions in absence and in presence of Triton X-100 as a maximum suppressor and a temperature of 25OC has been investigated. Schemes for the mechanism of reductions occuring at the DME have been deduced. A method for analytical determination of selenite and tellurite in simple solutions as well as in a binary mixture in the presence of 4-14.10-3% Triton X-100 is reported. (author)
Dielectric Behaviour of Binary Mixture of 2-Chloroaniline with 2-Methoxyethanol and 2-Ethoxyethanol
Bhupesh G Nemmaniwar; Kalyankar, Namdeo V.; Pothaji L. Kadam
2013-01-01
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),...
Dielectric Behavior of Binary Mixture of 2, 3-Dichloroaniline with 2-Methoxyethanol at 200 C
Bhupesh G Nemmaniwar; Vijaykumar Panchal; Potaji Kadam
2014-01-01
Densities, viscosities, refractive indices, dielectric constant (ɛ`) and dielectric loss (ɛ``) of 2,3-Dichloroaniline (2,3-DCA) and 2-methoxyethanol (2-ME) for different mole fractions of 2,3-Dichloroaniline in binary mixture have been measured at single microwave frequency 10.985 GHz at 200C by Surber method at microwave X-band. The values of dielectric parameters (ɛ`and ɛ``) have been used to evaluate the molar polarization (P12) and loss tangent (tan δ) excess permittivity (Δɛ``), exces...
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.
Drag Coefficient of a Rigid Spherical Particle in a Near-Critical Binary Fluid Mixture
Okamoto, Ryuichi; Fujitani, Youhei; Komura, Shigeyuki
2013-08-01
We calculate the drag coefficient of a rigid spherical particle in an incompressible binary fluid mixture. A weak preferential attraction is assumed between the particle surface and one of the fluid components, and the difference in the viscosity between the two components is neglected. Using the Gaussian free-energy functional and solving the hydrodynamic equation explicitly, we can show that the preferential attraction makes the drag coefficient larger as the bulk correlation length becomes longer. The dependence of the deviation from the Stokes law on the correlation length, when it is short, turns out to be much steeper than the previous estimates.
Polymer-Enforced Crystallization of a Eutectic Binary Hard Sphere Mixture
Kozina, Anna; Díaz-Leyva, Pedro; Bartsch, Eckhard; Palberg, Thomas
2010-01-01
We prepared a buoyancy matched binary mixture of polydisperse polystyrene microgel spheres of size ratio 0.785 and at a volume fraction of 0.567 just below the kinetic glass transition. In line with theoretical expectations, a eutectic phase behavior was observed, but only a minor fraction of the samples crystallized at all. By adding a short non-adsorbing polymer we enforce inter-species fractionation into coexisting pure component crystals, which in turn also shows signs of intra-species fr...
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.
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.
Wave phenomena in bubbly liquid-vapour mixture
Energy Technology Data Exchange (ETDEWEB)
Bilicki, Z. [Polska Akademia Nauk, Gdansk (Poland). Inst. Maszyn Przeplywowych
2001-07-01
The mixture of a liquid and bubbles of its vapour is an excellent example of two-phase system where interesting wave phenomena take place. The occurrence of these phenomena in single-component two-phase mixtures can be attributed to the effect of strong thermodynamic non-equilibrium. During the flow of a two-phase mixture, mechanical non-equilibrium can also occur. Both types of non-equilibrium give rise to strong deformations of velocity and temperature fields in the liquid surrounding vapour bubbles. Specific features of the two-phase medium determine its wave properties, pronounced in its dispersive nature, meaning that the velocity of propagation of disturbances in the two-phase medium depends on their frequency. These above properties typical for the two-phase medium of low void fraction can be modelled using a concept of internal structure. In this concept, a model of continuum with the so-called operative parameters is assumed. The model is capable of predicting the phenomena such as: dispersive shock waves, pseudo-criticality, wave propagation and divergence between the hydrodynamic and thermodynamic pressure during flashing flow. (orig.)
Angulo Nunez, Gonzalo Manuel; Brucka, Marta; 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 m...
Biosorption of binary mixtures of heavy metals by green macro alga, Caulerpa lentillifera
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Prasert Pavasant
2004-02-01
Full Text Available Dried Caulerpa lentillifera was shown to have adsorption potential for Cu, Cd, Pb and Zn. The adsorption equilibrium was found to follow the Freundlich isotherm type. The adsorption of binary mixture of heavy metals solution onto the surface of the algae was found to be of competitive type where the adsorption capacity for any single metal decreased by 10-40% in the presence of the others. The total adsorption capacity of the algae was, in most cases, found to decrease by 30-50% when there was more than one heavy metal in the solution. However, the adsorption of mixtures of Cd and Cu, and of Pb and Cu did not show a reductionin the total adsorption capacity.
Lotfy, Hayam Mahmoud; Salem, Hesham; Abdelkawy, Mohammad; Samir, Ahmed
2015-04-01
Five spectrophotometric methods were successfully developed and validated for the determination of betamethasone valerate and fusidic acid in their binary mixture. Those methods are isoabsorptive point method combined with the first derivative (ISO Point - D1) and the recently developed and well established methods namely ratio difference (RD) and constant center coupled with spectrum subtraction (CC) methods, in addition to derivative ratio (1DD) and mean centering of ratio spectra (MCR). New enrichment technique called spectrum addition technique was used instead of traditional spiking technique. The proposed spectrophotometric procedures do not require any separation steps. Accuracy, precision and linearity ranges of the proposed methods were determined and the specificity was assessed by analyzing synthetic mixtures of both drugs. They were applied to their pharmaceutical formulation and the results obtained were statistically compared to that of official methods. The statistical comparison showed that there is no significant difference between the proposed methods and the official ones regarding both accuracy and precision.
International Nuclear Information System (INIS)
Highlights: • Solubility of (-)-shikimic acid in different pure solvents was studied. • Solubility of (-)-shikimic acid in (H2O + ethanol) binary solvent mixtures was studied. • The solubility data were fitted using three semiempirical models. • The Gibbs free energy, enthalpy, entropy were calculated by the van’t Hoff analysis. - Abstract: In this paper, we focused on solubility and solution thermodynamics of (-)-shikimic acid. The solubility of (-)-shikimic acid ((3R,4S,5R)-(E)-3,4,5-trihydroxy-1-cyclohexenecarboxylic acid, CASRN 138-59-0) in H2O, ethanol, n-propanol, isopropanol, n-pentanol, n-heptane and in (H2O + ethanol) binary solvent mixtures was measured at temperatures from (303.45 to 362.15) K using the synthetic method under atmospheric pressure. Its corresponding (solid + liquid) equilibrium results will provide essential support for industrial design and further theoretical studies. The solubility of (-)-shikimic acid in H2O, ethanol, n-propanol, isopropanol, n-pentanol, n-heptane and in (H2O + ethanol) binary solvent mixtures were correlated with the Apelblat equation, the λh equation and the ideal equation. In addition, the thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy, were calculated by the van’t Hoff analysis. The experimental results showed that ethanol could be used as effective antisolvents in the crystallization process
Pawar, N. R.; Chimankar, O. P.; Bhandakkar, V. D.; Padole, N. N.
2012-12-01
The ultrasonic velocity (u), absorption (α), density (ρ), and viscosity (η) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (βa), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.
International Nuclear Information System (INIS)
The ultrasonic velocity (u), absorption (α), density (ρ), and viscosity (η) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (βa), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.
International Nuclear Information System (INIS)
The densities of binary mixtures of {isoamyl acetate + alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol)}, 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, VmE, thermal expansion coefficients, α, and their excess values, αE, were calculated from density data. The VmE 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 VmE values were correlated by Redlich-Kister equation and the extended real associated solution (ERAS) model was used for describing VmE values at T = 303.15 K.
Almandoz, M. C.; Sancho, M. I.; Blanco, S. E.
2014-01-01
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.
Derivation of an equation of surface tension isotherm for binary mixtures
International Nuclear Information System (INIS)
Surface tension was determined by integration of Gibbs adsorption equation from changing composition of surface layer of binary solutions with varying composition of volume solution being in equilibrium with it. The equation, which was tested for the Cd - Pb and Pb - Bi solutions at 773 K, was obtained. The isotherms of surface tension of liquid binary solutions was noted to be calculated using relation x2(ω) = f(x2) (x2(ω) - molar fraction of the second component) with rather close approximation at known dependence of the coefficient of the second component activity from the composition of solution at T = const. Surface layer of the Cd - Pb solutions was found to enrich with lead atoms
Liquid-liquid and solid-liquid equilibria of 2-isopropoxyethanol-H{sub 2}O-NaCl mixtures
Energy Technology Data Exchange (ETDEWEB)
Zijlema, T.G.; Witkamp, G.J.; Rosmalen, G.M. van
1999-12-01
Liquid-liquid equilibria experiments demonstrated that mixtures of 2-isopropoxyethanol and water saturated with NaCl are partially miscible. The lower critical solution temperature was estimated to be 29.2 C at a 2-isopropoxyethanol concentration of 0.399 (m{sub IPE}/(m{sub IPE} + m{sub H{sub 2}O})). Solid-liquid equilibria experiments showed that the solubility of NaCl in water is reduced significantly by the presence of 2-isopropoxyethanol. As in pure water, the NaCl solubility in 2-isopropoxyethanol-H{sub 2}O mixtures increases weakly with temperature.
Discriminative Stimulus Effects of Binary Drug Mixtures: Studies with Cocaine, MDPV, and Caffeine.
Collins, Gregory T; Abbott, Megan; Galindo, Kayla; Rush, Elise L; Rice, Kenner C; France, Charles P
2016-10-01
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
Directory of Open Access Journals (Sweden)
Zhao Shuo
2014-12-01
Full Text Available Batch time requirements are provided for the separation of binary zeotropic mixtures in two different multivessel columns (with and without vapor bypass, a non-cyclic two-vessel column and a regular batch column based on dynamic simulations. The first three columns are operated as closed (total reflux systems and the regular batch column is operated as an open (partial reflux system. We analyze the effects of feed composition, relative volatility and product specification on the time requirements. The multivessel arrangements perform better than the regular batch column, which requires from 4.00 to 34.67% more time to complete a given separation. The elimination of the vapor bypass in the multivessel column is impractical though it has a positive effect on the batch time requirements. Thus, the multivessel column, with the vapor stream bypassing the intermediate vessel, is proposed as the best candidate for a binary zeotropic mixture with low concentration of light component, low relative volatility and high product purity demand. Furthermore, an experimental multivessel column with vapor bypass is built and the corresponding experiments verify the simulations.
Dielectric Behaviour of Binary Mixture of 2-Chloroaniline with 2-Methoxyethanol and 2-Ethoxyethanol
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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.
Methane-benzene binary mixture destruction in a reverse flow catalytic reactor
International Nuclear Information System (INIS)
A reverse flow reactor (RFR) is a packed catalytic bed reactor in which feed flow direction is periodically reversed. When an exothermic catalytic combustion is conducted in a RFR, a hot zone is trapped in the center while both ends of the reactor act as regenerative heat exchanger. This enables an auto thermal operation at high temperatures even for feeds having a low adiabatic temperature rise. These features make RFR highly competitive for VOCs combustion. An experimental study of binary mixture purification in bench scale reverse flow reactor, with an inner diameter of 60 mm, has been carried out. Methane and benzene are chosen due to their different properties. The ignition temperature of methane is higher than any other hydrocarbons and benzene is widely used as solvent in industry. With periodic reversal feed, auto thermal catalytic combustion of very lean binary mixture can be achieved. When peak temperature in the hot zone reaches about 550 degree Celsius, both methane and benzene are well removed and little NOx or no other secondary pollutants are detected. The influence of several operation parameters, such as gas velocity, cycle period and methane-to-benzene ratio are discussed. A mathematical model has been developed and solved using a FORTRAN code, good correspondence being observed between both approaches. This provides a solution if VOC concentration in the contaminated air is too low to maintain an auto thermal operation, while natural gas (which is mainly methane) can be added as auxiliary fuel. (author)
Directory of Open Access Journals (Sweden)
Aistė Liekytė
2011-12-01
Full Text Available This article investigates toxic effects of heavy metals (Ni, Cu and their binary mixture (Ni+Cu on the cardio-respiratory system of rainbow trout (Oncorhynchus mykiss larvae depending on the type of metal, metal concentration and the duration of their exposure. The one-day larvae of rainbow trout were exposed to Ni (0,1; 0,2 mg/l, respectively, Cu (0,25; 0;5 mg/l, respectively and their binary mixture. During long-term exposure (30 days, the physiological parameters of larvae, e.g. heart rate (counts/min, gill ventilation frequency (counts/min after 5, 10 and 20 days of exposure were recorded. During experimental studies, the effects of heavy metals and their binary mixture on the heart rate and gill ventilation frequency of rainbow trout larvae depending on the type of metal, their concentrations and exposure duration were determined. Consequently, comparative studies on toxic effects of heavy metals and their binary mixture on the cardio-respiratory system of rainbow trout larvae showed that the binary mixture was more toxic to larvae than to single metals.Article in Lithuanian
Lin, Hsi-Hsin; Peng, Jia-De; Suryanarayanan, V.; Velayutham, D.; Ho, Kuo-Chuan
2016-04-01
In this work, eight new ionic liquids (ILs) based on triethylammonium (TEA) or n-methylpiperidinium (NMP) cations and perfluoro carboxylate (PFC) anions having different carbon chain lengths are synthesized and their physico-chemical properties such as density, decomposition temperature, viscosity and conductivity are determined. Photovoltaic characteristics of dye-sensitized solar cells (DSSCs) with binary ionic liquids electrolytes, containing the mixture of the synthesized ILs and 1-methyl-3-propyl imidazolium iodide (PMII) (v/v = 35/65), are evaluated. Among the different ILs, solar cells containing NMP based ILs show higher VOC than that of TEA, whereas, higher JSC is noted for the DSSCs incorporated with the latter when compared to the former. Further, the photo-current of the DSSCs decreases with the increase of the carbon chain length of perfluoro carboxylate anionic group of ILs. The cell performance of the DSSC containing ternary ionic liquids-based electrolytes compose of NMP-2C/TEA-2C/PMII (v/v/v = 28/7/65) exhibits a JSC of 12.99 mA cm-2, a VOC of 639.0 mV, a FF of 0.72, and a cell efficiency of 6.01%. The extraordinary durability of the DSSC containing the above combination of electrolytes stored in dark at 50 °C is proved to be unfailing up to 1200 h.
Equation of state for thermodynamic properties of pure and mixtures liquid alkali metals
Energy Technology Data Exchange (ETDEWEB)
Mousazadeh, M.H., E-mail: mmousazadeh@aeoi.org.ir [Department of Chemistry, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), End of North-Karegar Str., 11365-3486 Tehran (Iran, Islamic Republic of); Faramarzi, E. [Department of Physical Chemistry, School of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Maleki, Z. [Department of Chemistry, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), End of North-Karegar Str., 11365-3486 Tehran (Iran, Islamic Republic of)
2010-11-20
We developed an equation of state based on statistical-mechanical perturbation theory for pure and mixtures alkali metals. Thermodynamic properties were calculated by the equation of state, based on the perturbed-chain statistical associating fluid theory (PC-SAFT). The model uses two parameters for a monatomic system, segment size, {sigma}, and segment energy, {epsilon}. In this work, we calculate the saturation and compressed liquid density, heat capacity at constant pressure and constant volume, isobaric expansion coefficient, for which accurate experimental data exist in the literatures. Results on the density of binary and ternary alkali metal alloys of Cs-K, Na-K, Na-K-Cs, at temperatures from the freezing point up to several hundred degrees above the boiling point are presented. The calculated results are in good agreement with experimental data.
A Surface Tension Model for Liquid Mixtures Based on NRTL Equation
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A new equation for predicting surface tension is proposed based on the thermodynamic definition of surface tension and the expression of the Gibbs free energy of the system. Using the NRTL equation to represent the excess Gibbs free energy, a two-parameter surface tension equation is derived. The feasibility of the new equation has been tested in terms of 124 binary and 16 multicomponent systems(13-ternary and 3-quaternary) with absolute relative deviations of 0.59% and 1.55% respectively. This model is also predictive for the temperature dependence of surface tension of liquid mixtures. It is shown that, with good accuracy, this equation is simple and reliable for practical use.
Barata, Carlos; Baird, D J; Nogueira, A J A; Soares, A M V M; Riva, M C
2006-06-10
Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a "fixed ratio design" where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides (lambda-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for lethal effects
Energy Technology Data Exchange (ETDEWEB)
Barata, Carlos [Laboratory of Environmental Toxicology, Universitat Poltiecnica de Catalunya, CN 150 Km 14.5, Terrassa 08220 (Spain)]. E-mail: barata@intexter.upc.edu; Baird, D.J. [National Water Research Institute (Environment Canada) at Canadian Rivers Institute, 10 Bailey Drive, PO Box 45111, University of New Brunswick, Fredericton E3B 6E1, New Brunswick (Canada); Nogueira, A.J.A. [Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Soares, A.M.V.M. [Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Riva, M.C. [Laboratory of Environmental Toxicology, Universitat Poltiecnica de Catalunya, CN 150 Km 14.5, Terrassa 08220 (Spain)
2006-06-10
Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a 'fixed ratio design' where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides ({lambda}-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for
International Nuclear Information System (INIS)
Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a 'fixed ratio design' where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides (λ-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for lethal effects
Dielectrophoretic manipulation of the mixture of isotropic and nematic liquid
Kim, Soo-Dong; Lee, Bomi; Kang, Shin-Woong; Song, Jang-Kun
2015-08-01
In various applications involving liquid crystals, the manipulation of the nanoscale molecular assembly and microscale director alignment is highly useful. Here we show that a nematic-isotropic mixture, a unique bi-liquid system, has potential for the fabrication of microstructures having an ordered phase within a disordered phase, or vice versa. The volume expansion and shrinkage, migration, splitting, mergence and elongation of one phase within the other are easily accomplished via thermal treatment and dielectrophoretic manipulation. This is particularly achievable when one phase is suspended in the middle. In that case, a highly biased ordered-phase preference of surfaces, that is, the nematic-philic nature of a polyimide layer and the nematic-phobic nature of a self-assembled monolayer of chlorosilane derivatives, is used. Further, by combining this approach with photopolymerization, the patterned microstructure is solidified as a patterned polymer film having both isotropic and anisotropic molecular arrangements simultaneously, or as a template with a morphological variation.
Improvement of supercritical CO2 Brayton cycle using binary gas mixture
International Nuclear Information System (INIS)
recuperated layout and recompression layout Brayton cycles. For verification, existing design values of GTHTR 300, based on helium Brayton cycle, were used. Main input parameters were referred to Dostal's work as a reference cycle. The cycle performance evaluations were conducted for CO2-He, CO2-Ar, CO2-N2 and CO2-O2 binary mixtures by the developed cycle code. CO2-Xe mixture cycle was excluded in the pre-analysis since there is no mixture data. The mixed ratio of adding component was adjusted to specify the same critical temperature to be unbiased. The difference of binary gas mixture cycles compared to S-CO2 cycle was decrease in minimum cycle temperature and changes in minimum pressure and working fluids. Through the simulation, the CO2-He binary mixture was found out to be the highest increase of cycle efficiency: 1.73 % when the critical temperature was at 292 K for recompression cycle layout. Unlike the CO2-He binary mixture, the cycle efficiencies of CO2-Ar, CO2-N2, and CO2-O2 binary mixtures decreased compared to the pure S-CO2 cycle: -0.71 %, -1.35 % and -1.16 %, respectively. It was found that the increment of critical pressure led to a decrease in cycle operating pressure ratio which resulted in a negative effect on total cycle efficiency. The validation for the simulation was conducted by measuring the critical point of CO2-He mixture. The result clearly showed that the both critical temperature and critical pressure increase while the amount of added helium increases. The prediction of the property program indicates the opposite result and it means that the simulated CO2-He cycle is not a supercritical Brayton cycle. For the option of CO2-Xe mixture, the properties can be calculated based on ideal mixing rule and also can be modified with experimental data. With the proposed method, the efficiency of CO2-Xe mixture cycle is expected to increase by 1.28 %
International Nuclear Information System (INIS)
Bubble point temperatures at 95.23 kPa, over the entire composition range are measured for the binary mixtures formed by p-cresol with 1,2-dichloroethane, 1,1,2,2-tetrachloroethane trichloroethylene, tetrachloroethylene, and o- , m- , and p-xylenes, making use of a Swietoslawski-type ebulliometer. Liquid phase mole fraction (x 1) versus bubble point temperature (T) measurements are found to be well represented by the Wilson model. The optimum Wilson parameters are used to calculate the vapor phase composition, activity coefficients, and excess Gibbs free energy. The results are discussed
Interfacial properties of binary mixtures of square-well molecules from Monte Carlo simulation
Martínez-Ruiz, F. J.; Blas, F. J.
2016-04-01
We determine the interfacial properties of mixtures of spherical square-well molecules from direct simulation of the vapor-liquid interface. We consider mixtures with the same molecular size and intermolecular potential range but different dispersive energy parameter values. We perform Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of mixtures of square-well molecules. In particular, we determine the pressure tensor using the mechanical (virial) route and the vapor-liquid interfacial tension evaluated using the Irving-Kirkwood method. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, and interfacial thickness as functions of pressure, at a given temperature. This work can be considered as the extension of our previous work [F. J. Martínez-Ruiz and F. J. Blas, Mol. Phys. 113, 1217 (2015)] to deal with mixtures of spherical molecules that interact through a discontinuous intermolecular potential. According to our results, the main effect of increasing the ratio between the dispersive energy parameters of the mixture, ɛ22/ɛ11, is to sharpen the vapor-liquid interface and to increase the width of the biphasic coexistence region. Particularly interesting is the presence of a relative maximum in the density profiles of the more volatile component at the interface. This maximum is related with adsorption or accumulation of these molecules at the interface, since there are stronger attractive interactions between these molecules in comparison with the rest of intermolecular interactions. Also, the interfacial thickness decreases and the surface tension increases as ɛ22/ɛ11 is larger, a direct consequence of the increasing of the cohesive energy of the system.
Large attractive depletion interactions in soft repulsive-sphere binary mixtures.
Cinacchi, Giorgio; Martínez-Ratón, Yuri; Mederos, Luis; Navascués, Guillermo; Tani, Alessandro; Velasco, Enrique
2007-12-01
We consider binary mixtures of soft repulsive spherical particles and calculate the depletion interaction between two big spheres mediated by the fluid of small spheres, using different theoretical and simulation methods. The validity of the theoretical approach, a virial expansion in terms of the density of the small spheres, is checked against simulation results. Attention is given to the approach toward the hard-sphere limit and to the effect of density and temperature on the strength of the depletion potential. Our results indicate, surprisingly, that even a modest degree of softness in the pair potential governing the direct interactions between the particles may lead to a significantly more attractive total effective potential for the big spheres than in the hard-sphere case. This might lead to significant differences in phase behavior, structure, and dynamics of a binary mixture of soft repulsive spheres. In particular, a perturbative scheme is applied to predict the phase diagram of an effective system of big spheres interacting via depletion forces for a size ratio of small and big spheres of 0.2; this diagram includes the usual fluid-solid transition but, in the soft-sphere case, the metastable fluid-fluid transition, which is probably absent in hard-sphere mixtures, is close to being stable with respect to direct fluid-solid coexistence. From these results, the interesting possibility arises that, for sufficiently soft repulsive particles, this phase transition could become stable. Possible implications for the phase behavior of real colloidal dispersions are discussed. PMID:18067358
(Liquid plus liquid) equilibria of binary polymer solutions using a free-volume UNIQUAC-NRF model
DEFF Research Database (Denmark)
Radfarnia, H.R.; Ghotbi, C.; Taghikhani, V.;
2006-01-01
+ liquid) equilibria (LLE) for a number of binary polymer solutions at various temperatures. The values for the binary characteristic energy parameters for the proposed model and the FV-UNIQUAC model along with their average relative deviations from the experimental data were reported. It should be stated...... that the binary polymer solutions studied in this work were considered as monodisperse. The results obtained from the FV-UNIQUAC-NRF model were compared with those obtained from the FV-UNIQUAC model. The results of the proposed model show that the FV-UNIQUAC-NRF model can accurately correlate the...... capability in predicting the LCST for binary polymer solutions....
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.
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 ...
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. PMID:26840645
Prediction and assessment of ecogenotoxicity of antineoplastic drugs in binary mixtures.
Kundi, Michael; Parrella, Alfredo; Lavorgna, Margherita; Criscuolo, Emma; Russo, Chiara; Isidori, Marina
2016-08-01
The combined genotoxic effects of four anticancer drugs (5-fluorouracil [5-FU], cisplatin [CDDP], etoposide [ET], and imatinib mesylate [IM]) were studied testing their binary mixtures in two crustaceans that are part of the freshwater food chain, namely Daphnia magna and Ceriodaphnia dubia. Genotoxicity was assessed using the in vivo comet assay. Assessment was based on two distinct effect sizes determined from dose-response experiments. Doses for single and combined exposures expected to result in these effect sizes were computed based on Bliss independence as reference model. Statistical comparison by analysis of variance of single and combined toxicities allowed accepting or rejecting the independency hypothesis. The results obtained for D. magna showed independent action for all mixtures except for IM+5-FU that showed an antagonistic interaction. In C. dubia, most mixtures had antagonist interactions except IM+5-FU and IM+CDDP that showed Bliss independence. Despite the antagonistic interactions, our results demonstrated that combinations of anticancer drugs could be of environmental concern because effects occur at very low concentrations that are in the range of concentrations encountered in aquatic systems. PMID:26139396
Tracking three-phase coexistences in binary mixtures of hard plates and spheres
Aliabadi, Roohollah; Moradi, Mahmood; Varga, Szabolcs
2016-02-01
The stability of demixing phase transition in binary mixtures of hard plates (with thickness L and diameter D) and hard spheres (with diameter σ) is studied by means of Parsons-Lee theory. The isotropic-isotropic demixing, which is found in mixtures of large spheres and small plates, is very likely to be pre-empted by crystallization. In contrast, the nematic-nematic demixing, which is obtained in mixtures of large plates and small spheres, can be stabilized at low diameter ratios (σ/D) and aspect ratios (L/D). At intermediate values of σ/D, where the sizes of the components are similar, neither the isotropic-isotropic nor the nematic-nematic demixing can be stabilized, but a very strong fractionation takes place between a plate rich nematic and a sphere rich isotropic phases. Our results show that the excluded volume interactions are capable alone to explain the experimental observation of the nematic-nematic demixing, but they fail in the description of isotropic-isotropic one [M. Chen et al., Soft Matter 11, 5775 (2015)].
Sierra, M B; Pedroni, V I; Buffo, F E; Disalvo, E A; Morini, M A
2016-06-01
Temperature dependence of the zeta potential (ZP) is proposed as a tool to analyze the thermotropic behavior of unilamellar liposomes prepared from binary mixtures of phosphatidylcholines in the absence or presence of ions in aqueous suspensions. Since the lipid phase transition influences the surface potential of the liposome reflecting a sharp change in the ZP during the transition, it is proposed as a screening method for transition temperatures in complex systems, given its high sensitivity and small amount of sample required, that is, 70% less than that required in the use of conventional calorimeters. The sensitivity is also reflected in the pre-transition detection in the presence of ions. Plots of phase boundaries for these mixed-lipid vesicles were constructed by plotting the delimiting temperatures of both main phase transition and pre-transition vs. the lipid composition of the vesicle. Differential scanning calorimetry (DSC) studies, although subject to uncertainties in interpretation due to broad bands in lipid mixtures, allowed the validation of the temperature dependence of the ZP method for determining the phase transition and pre-transition temperatures. The system chosen was dipalmitoylphosphatidylcholine/dimyristoyl phosphatidylcholine (DMPC/DPPC), the most common combination in biological membranes. This work may be considered as a starting point for further research into more complex lipid mixtures with functional biological importance. PMID:26954086
Energy Technology Data Exchange (ETDEWEB)
McHale, M.E.R.; Horton, A.S.M.; Padilla, S.A.; Trufant, A.L.; De La Sancha, N.U.; Vela, E.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry
1996-11-01
Experimental solubilities are reported for pyrene dissolved in five binary alcohol + cyclohexanol and seven binary alcohol + 1-pentanol solvent mixtures at 26 C. Alcohol cosolvents include 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 3-methyl-1-butanol, and 2-pentanol. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the 12 systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.
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.
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：
Alonso de Mezquia, David; Wang, Zilin; Lapeira, Estela; Klein, Michael; Wiegand, Simone; Mounir Bou-Ali, M
2014-11-01
In this study, the thermodiffusion, molecular diffusion, and Soret coefficients of 12 binary mixtures composed of toluene, n-hexane and n-dodecane in the whole range of concentrations at atmospheric pressure and temperatures of 298.15 K and 308.15 K have been determined. The experimental measurements have been carried out using the Thermogravitational Column, the Sliding Symmetric Tubes and the Thermal Diffusion Forced Rayleigh Scattering techniques. The results obtained using the different techniques show a maximum deviation of 9% for the thermodiffusion coefficient, 8% for the molecular diffusion coefficient and 2% for the Soret coefficient. For the first time we report a decrease of the thermodiffusion coefficient with increasing ratio of the thermal expansion coefficient and viscosity for a binary mixture of an organic ring compound with a short n-alkane. This observation is discussed in terms of interactions between the different components. Additionally, the thermogravitational technique has been used to measure the thermodiffusion coefficients of four ternary mixtures consisting of toluene, n-hexane and n-dodecane at 298.15 K. In order to complete the study, the values obtained for the molecular diffusion coefficient in binary mixtures, and the thermodiffusion coefficient of binary and ternary mixtures have been compared with recently derived correlations. PMID:25376978
Centrifugal pumping of gas-liquid mixtures: a mechanistic approach
Energy Technology Data Exchange (ETDEWEB)
Estevam, Valdir [PETROBRAS, Rio de Janeiro, RJ (Brazil); Franca, Fernando A. [Universidade Estadual de Campinas, SP (Brazil); Alhanati, Francisco J.S. [C-Fer Technologies, Edmonton, Alberta (Canada)
2004-07-01
Centrifugal pumps are known to show a 'surging' behavior at certain conditions of free gas and liquid flow rate at the intake. In the 'surging region' on a pump characteristic curve, the head generated is significantly lower than if the pump were handling a gas-liquid homogeneous mixture. The surging happens, as one shows in this paper, due to the existence of a gas pocket, referred as 'elongated bubble', at the pump impeller inlet region. Therefore, to be able to predict the performance of centrifugal pumps under two-phase conditions, one has to disclose and model the mechanisms that set existence of the elongated bubble at the impeller inlet, besides calculating its length inside the impeller. This paper reports on the results of experimental and mechanistic modelling work conducted with the objective of better predicting the gas-liquid performance of centrifugal pumps under all range of conditions, including those characterized by 'surging'. The focus was on small diameter centrifugal pumps used to produce oil wells. A mechanistic two-fluid model devised to calculate the head generated by the pump was developed. The predictions of the model show good agreement with data collected for this study, and with data recently collected by other research organizations. (author)
Gel formation in a mixture of a block copolymer and a nematic liquid crystal.
Khazimullin, Maxim; Müller, Thomas; Messlinger, Stephan; Rehberg, Ingo; Schöpf, Wolfgang; Krekhov, Alexei; Pettau, Robin; Kreger, Klaus; Schmidt, Hans-Werner
2011-08-01
The viscoelastic properties of a binary mixture of a mesogenic side-chain block copolymer in a low molecular weight nematic liquid crystal are studied for mass concentrations ranging from the diluted regime up to a liquid crystalline gel state at about 3%. In the gel state, the system does not flow, exhibits a polydomain structure on a microscopic level, and strongly scatters light. Below the gelation point, the system is homogeneous and behaves like a usual nematic, so the continuum theory of liquid crystals can be applied for interpreting the experimental data. Using the dynamic Fréedericksz transition technique, the dependence of the splay elastic constant and the rotational viscosity on the polymer concentration have been obtained. Comparing the dynamic behavior of block copolymer solutions with the respective homopolymer solutions reveals that, above a mass concentration of 1%, self-assembling of the block copolymer chain segments in clusters occurred, resulting in a gel state at higher concentrations. The effective cluster size is estimated as a function of the concentration, and a scaling-law behavior near the sol-gel transition is confirmed. This technique may serve as an alternative method for determining the gelation point. PMID:21929007
Gel formation in a mixture of a block copolymer and a nematic liquid crystal
Khazimullin, Maxim; Müller, Thomas; Messlinger, Stephan; Rehberg, Ingo; Schöpf, Wolfgang; Krekhov, Alexei; Pettau, Robin; Kreger, Klaus; Schmidt, Hans-Werner
2011-08-01
The viscoelastic properties of a binary mixture of a mesogenic side-chain block copolymer in a low molecular weight nematic liquid crystal are studied for mass concentrations ranging from the diluted regime up to a liquid crystalline gel state at about 3%. In the gel state, the system does not flow, exhibits a polydomain structure on a microscopic level, and strongly scatters light. Below the gelation point, the system is homogeneous and behaves like a usual nematic, so the continuum theory of liquid crystals can be applied for interpreting the experimental data. Using the dynamic Fréedericksz transition technique, the dependence of the splay elastic constant and the rotational viscosity on the polymer concentration have been obtained. Comparing the dynamic behavior of block copolymer solutions with the respective homopolymer solutions reveals that, above a mass concentration of 1%, self-assembling of the block copolymer chain segments in clusters occurred, resulting in a gel state at higher concentrations. The effective cluster size is estimated as a function of the concentration, and a scaling-law behavior near the sol-gel transition is confirmed. This technique may serve as an alternative method for determining the gelation point.
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.
Binary mixtures of waxy wheat and conventional wheat as measured by NIR reflectance.
Delwiche, Stephen R; Graybosch, Robert A
2016-01-01
Waxy wheat contains very low concentration (generally 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. PMID:26695296
Longwave convection in a layer of binary mixture with modulated heat flux: weakly nonlinear analysis
International Nuclear Information System (INIS)
We consider dynamics of a binary mixture layer subject to a modulated heat flux at the bottom. Nonlinear evolution for longwave synchronous mode is shown to be governed by a set of nonlocal amplitude equations, solvability conditions of a certain linear nonhomogeneous problem. For the superlattice combining two hexagonal lattices, the set of nonlocal equations can be reduced to the set of Landau equations with cubic and quadratic nonlinear terms. Although this set is conventional for a small-amplitude analysis, in the present work it is valid even for finite-amplitude regimes; the perturbations of both temperature and solute concentration are of order unity, only their gradients are small. Nontrivial matching with known limiting cases is found. (paper)
Binary Mixture of Perfect Fluid and Dark Energy in Modified Theory of Gravity
Shaikh, A. Y.
2016-07-01
A self consistent system of Plane Symmetric gravitational field and a binary mixture of perfect fluid and dark energy in a modified theory of gravity are considered. The gravitational field plays crucial role in the formation of soliton-like solutions, i.e., solutions with limited total energy, spin, and charge. The perfect fluid is taken to be the one obeying the usual equation of state, i.e., p = γρ with γ∈ [0, 1] whereas, the dark energy is considered to be either the quintessence like equation of state or Chaplygin gas. The exact solutions to the corresponding field equations are obtained for power-law and exponential volumetric expansion. The geometrical and physical parameters for both the models are studied.
Investigation of solids segregation of binary mixtures in a rotating drum at various Froude numbers
Institute of Scientific and Technical Information of China (English)
HE Yu-rong; MEN Yu-bin; LIU Yuan-chun; LIU Wen-tie; DING Yu-long
2010-01-01
To investigate the effect of the Froude number(Fr)on solid segregation in a rotating drum,a two dimensional mathematical modelling on solids behaviour in horizontally oriented rotating drums operated in rolling,cascading and cataracting modes has been carried out by using Euler-Euler multi-fluid model in Fluent(R)6.2 environment.Small particles and big particles are used in the work as binary mixtures to investigate segregation characteristics.The effect of Froude number(rotating velocity)on the flow field is investigated.It is found that the model captures the main features of solids motion and segregation in the drum and numerical results agree well with limited experimental data for solid velocity.
Direct observation in 3d of structural crossover in binary hard sphere mixtures
Statt, Antonia; Pinchaipat, Rattachai; Turci, Francesco; Evans, Robert; Royall, C. Patrick
2016-04-01
For binary fluid mixtures of spherical particles in which the two species are sufficiently different in size, the dominant wavelength of oscillations of the pair correlation functions is predicted to change from roughly the diameter of the large species to that of the small species along a sharp crossover line in the phase diagram [C. Grodon et al., J. Chem. Phys. 121, 7869 (2004)]. Using particle-resolved colloid experiments in 3d we demonstrate that crossover exists and that its location in the phase diagram is in quantitative agreement with the results of both theory and our Monte-Carlo simulations. In contrast with previous work [J. Baumgartl et al., Phys. Rev. Lett. 98, 198303 (2007)], where a correspondence was drawn between crossover and percolation of both species, in our 3d study we find that structural crossover is unrelated to percolation.
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.
Phase behavior of binary hard-sphere mixtures from perturbation theory.
Velasco, E; Navascués, G; Mederos, L
1999-09-01
Using a first-order perturbation theory, we have studied the phase diagram of a binary mixture of hard spheres for different values of the size ratio. Recent models for the two-body depletion potential between large spheres are used to take into account the role of the small spheres. The theory predicts a complex phase diagram including a fluid-solid transition at high packing fraction of small spheres, metastability of fluid-fluid demixing, an isostructural solid-solid transition at high packing fraction of the large spheres for sufficiently small values of the size ratio q of the spheres, and the tendency to sticky-sphere behavior in the limit q-->0. The agreement with recent simulation results is quite good. We also show that this phenomenology was already implicit in the pioneering work of Asakura and Oosawa. PMID:11970123
Structure formation in binary mixtures of lipids and detergents: Self-assembly and vesicle division
Noguchi, Hiroshi
2013-01-01
Self-assembly dynamics in binary surfactant mixtures and structure changes of lipid vesicles induced by detergent solution are studied using coarse-grained molecular simulations. Disk-shaped micelles, the bicelles, are stabilized by detergents surrounding the rim of a bilayer disk of lipids. The self-assembled bicelles are considerably smaller than bicelles formed from vesicle rupture, and their size is determined by the concentrations of lipids and detergents and the interactions between the two species. The detergent-adsorption induces spontaneous curvature of the vesicle bilayer and results in vesicle division into two vesicles or vesicle rupture into worm-like micelles. The division occurs mainly via the inverse pathway of the modified stalk model. For large spontaneous curvature of the monolayers of the detergents, a pore is often opened, thereby leading to vesicle division or worm-like micelle formation.
Ramadan, Nesrin K.; El-Ragehy, Nariman A.; Ragab, Mona T.; El-Zeany, Badr A.
2015-02-01
Four simple, sensitive, accurate and precise spectrophotometric methods were developed for the simultaneous determination of a binary mixture containing Pantoprazole Sodium Sesquihydrate (PAN) and Itopride Hydrochloride (ITH). Method (A) is the derivative ratio method (1DD), method (B) is the mean centering of ratio spectra method (MCR), method (C) is the ratio difference method (RD) and method (D) is the isoabsorptive point coupled with third derivative method (3D). Linear correlation was obtained in range 8-44 μg/mL for PAN by the four proposed methods, 8-40 μg/mL for ITH by methods A, B and C and 10-40 μg/mL for ITH by method D. The suggested methods were validated according to ICH guidelines. The obtained results were statistically compared with those obtained by the official and a reported method for PAN and ITH, respectively, showing no significant difference with respect to accuracy and precision.
Longwave convection in a layer of binary mixture with modulated heat flux: weakly nonlinear analysis
Energy Technology Data Exchange (ETDEWEB)
Fayzrakhmanova, Irina S [Department of General Physics, Perm State Technical University, Perm 614990 (Russian Federation); Shklyaev, Sergey [Institute of Continuous Media Mechanics, Ural Branch of the Russian Academy of Sciences, Perm 614013 (Russian Federation); Nepomnyashchy, Alexander A, E-mail: shklyaev@yandex.ru, E-mail: nepom@math.technion.ac.il [Department of Mathematics, Technion—Israel Institute of Technology, Haifa 32000 (Israel)
2014-08-01
We consider dynamics of a binary mixture layer subject to a modulated heat flux at the bottom. Nonlinear evolution for longwave synchronous mode is shown to be governed by a set of nonlocal amplitude equations, solvability conditions of a certain linear nonhomogeneous problem. For the superlattice combining two hexagonal lattices, the set of nonlocal equations can be reduced to the set of Landau equations with cubic and quadratic nonlinear terms. Although this set is conventional for a small-amplitude analysis, in the present work it is valid even for finite-amplitude regimes; the perturbations of both temperature and solute concentration are of order unity, only their gradients are small. Nontrivial matching with known limiting cases is found. (paper)
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.
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.
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.)
Self-Propulsion Mechanism of Active Janus Particles in Near-Critical Binary Mixtures
Samin, Sela; van Roij, René
2015-10-01
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 droplet that nucleates around the particle. Thus, the often-used concept of a surface velocity cannot account for the self-propulsion. The particle's swimming velocity is related to the droplet shape and size, which is determined by a so-called critical isotherm. Two distinct swimming regimes exist, depending on whether the droplet partially or completely covers the particle. Interestingly, the dependence of the swimming velocity on temperature is nonmonotonic in both regimes.
Mass-dependence of self-diffusion coefficients in disparate-mass binary fluid mixtures
Directory of Open Access Journals (Sweden)
I. Binas
2009-01-01
Full Text Available Self-diffusion coefficients of a binary fluid mixture with components differing only in their particle masses are studied, in particular the case when mass ratio μ of light and heavy particles tends to zero. These coefficients were calculated within the memory function formalism, using the systematic subsequence of approximations for the relaxation times of velocity autocorrelation function. We obtained a general relation for the self-diffusion coefficients which show polynomial dependence on the mass ratio μ. The obtained expression has a correct Brownian limit. We developed the hierarchy of approximations for the self-diffusion coefficients that tends to an exact result from above and below when the order of approximations increases.
International Nuclear Information System (INIS)
Highlights: • The solubility increased with increasing temperature. • The solubility decreased with the rise of the ratio of the methanol. • The solubility data were fitted using Apelblat equation, CNIBS/R–K and JA model. • The Gibbs free energy, enthalpy and entropy were calculated by the van’t Hoff analysis. - Abstract: In this paper, we focused on solubility and solution thermodynamics of dibenzothiophene. By the gravimetric method, the solubility of dibenzothiophene was measured in (methanol + acetonitrile) binary solvent mixtures at temperatures from (278.15 to 333.15) K under atmosphere pressure. The solubility data were fitted using a modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redich–Kister (CNIBS/R–K) model and Jouyban–Acree model. Computational results showed that the modified Apelblat equation was superior to the other two equations. In addition, the thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy, were calculated by the van’t Hoff analysis. The experimental results showed that methanol could be used as effective anti-solvents in the crystallization process
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. PMID:20655372
International Nuclear Information System (INIS)
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
Bhattacharjee, Jayanta K.; Kaatze, Udo; Mirzaev, Sirojiddin Z.
2010-06-01
The nature and origin of sound attenuation due to critical fluctuations near the liquid consolute point are discussed. Starting from basic principles, the background of critical phenomena is reviewed and the conceptions of theoretical approaches to describe the critical contributions to the propagation of sound are analysed. Experimental broadband spectra of suitable binary systems are evaluated jointly with results from quasi-elastic light scattering, shear viscosity and heat capacity measurements to verify or disprove theoretical predictions. It is shown that spectra of systems without or with only small-amplitude ultrasonic contribution from noncritical relaxation processes can be represented by theory with the asymptotic high-frequency sonic attenuation coefficient as a simple adjustable parameter. As a result, sonic spectra of more complex systems, exhibiting significant contributions from noncritical ultrasonic relaxations, are discussed assuming the critical part to be known from theory and auxiliary data. This modus operandi allows for a clear extraction of parameters relevant to the noncritical elementary processes in liquid mixtures, such as conformational changes, protolysis and hydrolysis reactions, monomer exchange from micelles and rotational isomerizations of membrane molecules. The influence of the critical dynamics on the noncritical kinetics is disclosed for some topical examples.
Monupal, Suthar, B.
2016-05-01
The ultrasonic velocities, compressibility and bulk modulus of binary mixtures of aqueous solution of isopropyl alcohol with mustard oil have been measured at different concentrations at room temperature. The results are varied with the concentration in such a way i.e. ultrasonic velocity and Bulk Modulus is decreases with the increase in concentration and compressibility is increases with the increase in concentration of aqueous isopropyl alcohol. It is due to molecular interactions present in the mixtures.
International Nuclear Information System (INIS)
The modified Waldmann equation (MWE) has been applied to the separation of binary gas mixtures in a thermal diffusion column. However, the application is difficult for a mixture where the molecular weight and viscosity of each component differs greatly from each other. Therefore, a column was divided into 50 theoretical local columns, and the MWE calculation in each local column was repeated for the stack of 50. The composition distribution along the column can be determined by this method. (author)
Guevara-Carrion, Gabriela; Vrabec, Jadran; Hasse, Hans
2011-02-01
Density, self-diffusion coefficient, and shear viscosity of pure liquid water are predicted for temperatures between 280 and 373 K by molecular dynamics simulation and the Green-Kubo method. Four different rigid nonpolarizable water models are assessed: SPC, SPC/E, TIP4P, and TIP4P/2005. The pressure dependence of the self-diffusion coefficient and the shear viscosity for pure liquid water is also calculated and the anomalous behavior of these properties is qualitatively well predicted. Furthermore, transport properties as well as excess volume and excess enthalpy of aqueous binary mixtures containing methanol or ethanol, based on the SPC/E and TIP4P/2005 water models, are calculated. Under the tested conditions, the TIP4P/2005 model gives the best quantitative and qualitative agreement with experiments for the regarded transport properties. The deviations from experimental data are of 5% to 15% for pure liquid water and 5% to 20% for the water + alcohol mixtures. Moreover, the center of mass power spectrum of water as well as the investigated mixtures are analyzed and the hydrogen-bonding structure is discussed for different states.
DEFF Research Database (Denmark)
Tsivintzelis, Ioannis; Kontogeorgis, Georgios
2009-01-01
The vapor–liquid equilibria of binary polymer–solvent systems was modeled using the Non-Random Hydrogen Bonding (NRHB) model. Mixtures of poly(ethylene glycol), poly(propylene glycol), poly(vinyl alcohol) and poly(vinyl acetate) with various solvents were investigated, while emphasis was put on...... hydrogen bonding systems, in which functional groups of the polymer chain can self-associate or cross-associate with the solvent molecules. Effort has been made to explicitly account for all hydrogen bonding interactions. The results reveal that the NRHB model offers a flexible approach to account for...
Ashton, Douglas J.; Liu, Jiwen; Luijten, Erik; Wilding, Nigel B.
2010-11-01
Highly size-asymmetrical fluid mixtures arise in a variety of physical contexts, notably in suspensions of colloidal particles to which much smaller particles have been added in the form of polymers or nanoparticles. Conventional schemes for simulating models of such systems are hamstrung by the difficulty of relaxing the large species in the presence of the small one. Here we describe how the rejection-free geometrical cluster algorithm of Liu and Luijten [J. Liu and E. Luijten, Phys. Rev. Lett. 92, 035504 (2004)] can be embedded within a restricted Gibbs ensemble to facilitate efficient and accurate studies of fluid phase behavior of highly size-asymmetrical mixtures. After providing a detailed description of the algorithm, we summarize the bespoke analysis techniques of [Ashton et al., J. Chem. Phys. 132, 074111 (2010)] that permit accurate estimates of coexisting densities and critical-point parameters. We apply our methods to study the liquid-vapor phase diagram of a particular mixture of Lennard-Jones particles having a 10:1 size ratio. As the reservoir volume fraction of small particles is increased in the range of 0%-5%, the critical temperature decreases by approximately 50%, while the critical density drops by some 30%. These trends imply that in our system, adding small particles decreases the net attraction between large particles, a situation that contrasts with hard-sphere mixtures where an attractive depletion force occurs.
Katranchev, B.; Petrov, M.; Keskinova, E.; Naradikian, H.; Rafailov, P. M.; Dettlaff-Weglikowska, U.; Spassov, T.
2014-12-01
The liquid crystalline (LC) nature of alkyloxybenzoic acids is preserved after adding of any mesogenic or non-mesogenic compound through hydrogen bonding. However, this noncovalent interaction provokes a sizable effect on the physical properties as, e. g. melting point and mesomorphic states. In the present work we investigate nanocomposites, prepared by mixture of the eighth homologue of p-n-alkyloxybenzoic acids (8OBA) with single-walled carbon nanotubes (SWCNT) with the purpose to modify the optical properties of the liquid crystal. We exercise optical control on the LC system by inserting SWCNT specially functionalized by carboxylic groups. Since the liquid crystalline state combines order and mobility at the molecular (nanoscale) level, molecular modification can lead to different macroscopical nanocomposite symmetry. The thermal properties of the functionalized nanocomposite are confirmed by DSC analyses. The mechanism of the interaction between surface-treated nanoparticles (functionalized nanotubes) and the liquid crystal 8OBA bent- dimer molecules is briefly discussed.
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.
International Nuclear Information System (INIS)
In this paper, direct non-equilibrium molecular dynamics simulation is developed to investigate thermal conductivity and thermal diffusion factors of confined binary mixtures of methane and some n-alkanes in a nanochannel. We used two thermal walls in different temperatures to impose temperature gradient in the system. The mixtures are confined between two parallel atomic walls, normal to temperature gradient. Simulation results show high inhomogeneity and layering in the mixtures. Thermal conductivity of mixtures increases with decreasing the channel width and increases in mixtures with high concentration of methane. Except for very small channels, confinement has minimal effect on thermal diffusion. In very narrow channels, thermal diffusion is small and it reaches a steady state value with increasing the channel width. Local velocity fields for two different channels also show different behaviors. In relatively large channels some convection patterns are observed in mixtures
International Nuclear Information System (INIS)
Highlights: ► A new apparatus for the determination of VLE is presented. ► The first vapor pressures for binary mixtures containing aprotic solvents in IL are reported. ► Calculated activity coefficients and osmotic coefficients reveal a strong non-ideal behavior. ► A more detailed study of the highly diluted IL concentration range is necessary to test the Debye–Hückel law. - Abstract: A new apparatus for the determination of VLE has been constructed which works for absolute pressure measurements as well as for measuring differential pressures. The first results obtained are (vapor + liquid) equilibria (VLE) of binary mixtures containing acetonitrile or tetrahydrofuran and the ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIm][NTf2] by using the absolute pressures method. VLE measurements were carried out over the whole concentration range at four different temperatures between 293.15 K and 313.15 K. Activity coefficients (γ1) of the solvents in [EMIm][NTf2] and their osmotic coefficients (φ1) have been determined from the VLE data.
International Nuclear Information System (INIS)
Chlorpyrifos (CPF) and diazinon (DZN) are two commonly used organophosphorus (OP) insecticides and a potential exists for concurrent exposures. The primary neurotoxic effects from OP pesticide exposures result from the inhibition of acetylcholinesterase (AChE). The pharmacokinetic and pharmacodynamic impact of acute binary exposures of rats to CPF and DZN was 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 postdosing, 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, RBC, and plasma. Coexposure to CPF/DZN at the low dose of 15/15 mg/kg did not alter the pharmacokinetics of CPF, DZN, or their metabolites in blood. A high binary dose of 60/60 mg/kg increased the C max and AUC and decreased the clearance for both parent 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 coexposures, and the extent of inhibition was plasma > RBC ≥ brain. The overall relative potency for ChE inhibition was CPF/DZN > CPF > DZN. A comparison of the ChE response at the low binary dose (15/15 mg/kg), where there were no apparent pharmacokinetic interactions, suggested that the overall ChE response was additive. These experiments represent important data concerning the potential pharmacokinetic and pharmacodynamic interactions for pesticide mixtures and will provide needed insight for assessing the potential cumulative risk associated with occupational or environmental exposures to these insecticides
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)
Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions
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...
Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex
International Nuclear Information System (INIS)
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. - Highlights:: • 2 of 4 insecticide-Microcystis combinations showed no interactive effect on Daphnia. • One insecticide showed antagonistic deviation patterns. • For one other insecticide the results depended on the reference model used. • Interactive effects between insecticides and Microcystis cannot be generalized. • The concentration addition model provides conservative estimates of mixture effects. - Interactive effects between insecticides and cyanobacterial stressors cannot be generalized, not even for insecticides with closely related known modes of action
Hadžović, Ervina; Betz, Gabriele; Hadžidedić, Seherzada; El-Arini, Silvia Kocova; Leuenberger, Hans
2011-09-15
Roller compaction is a dry granulation method which results in tablets with inferior tensile strength comparing to direct compaction. The effect of roller compaction on compressibility and compactibility of tablets prepared from Theophylline anhydrate powder, Theophylline anhydrate fine powder and Theophylline monohydrate was investigated by measuring tensile strength of tablets as well as calculating compressibility and compactibility parameters by Leuenberger equation. The tablets under the same conditions were prepared by direct compaction and roller compaction. The binary mixtures of Theophylline anhydrate powder, Theophylline anhydrate fine powder, Theophylline monohydrate and microcrystalline cellulose were prepared in order to determine the optimal ratio of active material and excipients which delivers a sufficient mechanical strength of tablets. Tensile strength of MCC tablets and compactibility parameters calculated by Leuenberger equation after roller compaction was significantly decreased, while THAP, THAFP and THMO tablets showed only a minor reduction in compactibility and compressibility. Adding MCC to a mixture with Theophylline showed that the right choice and ratio of excipients can enable a sufficient mechanical strength of the tablets after roller compaction. PMID:21704142
Suppression of turbulent energy cascade due to phase separation in homogenous binary mixture fluid
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.
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...
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…
International Nuclear Information System (INIS)
Excess molar enthalpies, HmE and volumes, VmE were reported for binary mixtures of {nonafluorobutylmethylether (NFBME, C4F9-O-CH3)}+[five ethylene glycol ethers, EGEn,m-R, {CmH2m+1-(OCH2CH2)n-R, n=1 and 2, m=1 to 4, R=OH and OCH3}] at 298.15K. Results of excess molar enthalpies and volumes were positive over whole range of concentrations for all the mixtures. The magnitude was in order: EGE1,4-OH>EGE1,3-OH>EGE1,2-OH>EGE1,1-OH>EGE2,1-OH>EGE2,1-OCH3 for HmE and EGE2,1-OCH3>EGE1,4-OH>EGE1,3-OH>EGE1,2-OH>EGE1,1-OH>EGE2,1-OH for VmE at the maximum point. The curves of HmE and VmE for the EGE2,1-OH system were depressed in the middle mole fraction of NFBME, x1 suggesting a quasi-stable state in the solution. We observed occurrences of the stable emulsification state in solutions in concentrations range of 0.351m,2E,∞, and volumes, Vm,2E,∞, of EGEn,m-R at infinite dilution, apparent molar enthalpies of solvation, ΔsolvH2, of the EGEn,m-R in NFBME were evaluated. The dependence of these thermodynamic quantities on the number of carbon atoms in the alkyl group, m, the number of the ethylene oxide group, n, and the difference of R group were discussed in consideration of various kinds of intermolecular interactions in pure component liquids and solutions
Koller, Thomas M; Heller, Andreas; Rausch, Michael H; Wasserscheid, Peter; Economou, Ioannis G; Fröba, Andreas P
2015-07-01
Ionic liquids (ILs) are possible working fluids for the separation of carbon dioxide (CO2) from flue gases. For evaluating their performance in such processes, reliable mutual-diffusivity data are required for mixtures of ILs with relevant flue gas components. In the present study, dynamic light scattering (DLS) and molecular dynamics (MD) simulations were used for the investigation of the molecular diffusion in binary mixtures of the IL 1-ethyl-3-methylimidazolium tetracyanoborate ([EMIM][B(CN)4]) with the dissolved gases carbon dioxide, nitrogen, carbon monoxide, hydrogen, methane, oxygen, and hydrogen sulfide at temperatures from 298.15 to 363.15 K and pressures up to 63 bar. At conditions approaching infinite dilution of a gas, the Fick mutual diffusivity of the mixture measured by DLS and the self-diffusivity of the corresponding gas calculated by MD simulations match, which could be generally found within combined uncertainties. The obtained diffusivities are in agreement with literature data for the same or comparable systems as well as with the general trend of increasing diffusivities for decreasing IL viscosities. The DLS and MD results reveal distinctly larger molecular diffusivities for [EMIM][B(CN)4]-hydrogen mixtures compared to mixtures with all other gases. This behavior results in the failure of an empirical correlation with the molar volumes of the gases at their normal boiling points. The DLS experiments also showed that there is no noticeable influence of the dissolved gas and temperature on the thermal diffusivity of the studied systems. PMID:26075680
Ali, Anwar; Tasneem, Shadma; Nabi, Firdosa
2010-09-01
The densities (ρ), viscosities (η), and ultrasonic speeds (u) of pure cyclohexane, 1-butanol, 2- butanol, and those of their binary mixtures, with cyclohexane as common component, covering the whole composition range have been measured at 293.15, 298.15, 303.15, 308.15, 313.15, and 318.15 K. From the experimental data the excess molar volume (VE), deviations in isentropic compressibility (Δks), deviations in viscosity (Δη), deviations in ultrasonic speed (Δu), deviations in acoustic impedance (ΔZ), deviations in internal pressure (ΔPi), excess Gibbs free energy of activation (ΔG*E), entropies (ΔS*), and enthalpies (ΔH*) of activation of viscous flow have been determined. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. Partial molar volumes (V0φ,2) and partial molar compressibilities (K0φ,2) of 1-butanol and 2-butanol in cyclohexane have also been evaluated. Moreover, VE values were theoretically predicted by using Flory's statistical theory. The variations of derived parameters mentioned above with composition offer a convenient method to study the nature and extent of interactions between the component molecules of the liquid mixtures, not easily obtained by other means
Directory of Open Access Journals (Sweden)
M. V. Rathnam
2013-01-01
Full Text Available Densities, viscosities, and speed of sound have been determined at T = (303.15, 308.15, and 313.15 K for the binary mixtures of methyl benzoate with tetrahydrofuran, 1,4-dioxane, anisole, and butyl vinyl ether over the entire range of composition. Using these measured values, excess volume VE, deviation in viscosities Δη, excess Gibb’s free energy of activation for viscous flow ΔG*E, and deviation in isentropic compressibility Δks have been calculated. These calculated binary data have been fitted to Redlich-Kister equation to determine the appropriate coefficients. The values of excess volume VE and deviation in viscosities Δη are negative over the entire range of composition for all the binary systems at the studied temperatures. The behavior of these parameters with composition of the mixture has been discussed in terms of molecular interactions between the components of liquids.
Energy Technology Data Exchange (ETDEWEB)
Alonso, Victor; Garcia, Mario [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain); Gonzalez, Juan Antonio, E-mail: jagl@termo.uva.es [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain); Garcia De La Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain)
2011-07-10
Highlights: {yields} LLE coexistence curves were determined for mixtures of 2PhEE with alkanes. {yields} UCST values are higher for n-alkane systems than for solutions with cyclic alkanes. {yields} For the latter mixtures, UCST increases with the size of the alkyl group attached. {yields} Alkoxyethanol-alkoxyethanol interactions are enhanced by aromatic group in cellosolve. - Abstract: The coexistence curves of the liquid-liquid equilibria (LLE) for systems of 2-phenoxyethanol (2PhEE) with heptane, octane, cyclohexane, methylcyclohexane or ethylcyclohexane have been determined by the method of the critical opalescence using a laser scattering technique. All the curves show an upper critical solution temperature (UCST), have a rather horizontal top and their symmetry depends on the relative size of the mixture compounds. UCST values are higher for systems with linear alkanes than for solutions including cyclic alkanes. For these mixtures, the UCST increases with the size of the alkyl group attached to the cyclic part of the molecule. It is shown that interactions between alkoxyethanol molecules are stronger when the hydroxyether contains an aromatic group. Data are used to determine the critical exponent for the order parameter mole fraction. Values obtained are consistent with those provided by the Ising model or by the renormalization group theory.
International Nuclear Information System (INIS)
Highlights: → LLE coexistence curves were determined for mixtures of 2PhEE with alkanes. → UCST values are higher for n-alkane systems than for solutions with cyclic alkanes. → For the latter mixtures, UCST increases with the size of the alkyl group attached. → Alkoxyethanol-alkoxyethanol interactions are enhanced by aromatic group in cellosolve. - Abstract: The coexistence curves of the liquid-liquid equilibria (LLE) for systems of 2-phenoxyethanol (2PhEE) with heptane, octane, cyclohexane, methylcyclohexane or ethylcyclohexane have been determined by the method of the critical opalescence using a laser scattering technique. All the curves show an upper critical solution temperature (UCST), have a rather horizontal top and their symmetry depends on the relative size of the mixture compounds. UCST values are higher for systems with linear alkanes than for solutions including cyclic alkanes. For these mixtures, the UCST increases with the size of the alkyl group attached to the cyclic part of the molecule. It is shown that interactions between alkoxyethanol molecules are stronger when the hydroxyether contains an aromatic group. Data are used to determine the critical exponent for the order parameter mole fraction. Values obtained are consistent with those provided by the Ising model or by the renormalization group theory.
Asymmetrical phase separation and gelation in binary mixtures of oppositely charged colloids
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.
International Nuclear Information System (INIS)
Highlights: • Densities and viscosities from 278.15 to 333.15 K are reported for three binary (2,2,2-trifluoroethanol + an IL) systems. • TFE + [bmim][BF4] system presents positive VE values except for the highest mole fractions of TFE, at the highest temperatures. • TFE + [bmim][PF6] presents negative VE values except at the low TFE mole fractions for the lowest temperatures. • TFE + [bmim][NTf2] presents negative VE values for all the mole fractions and temperatures studied. • The three systems present negative viscosity deviations becoming less negative with increasing temperature. -- Abstract: Densities and viscosities were determined for binary mixtures of 2,2,2-trifluoroethanol (TFE) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([bmim][NTf2]) over the entire range of composition. The experimental measurements were carried out at temperatures ranging from 278.15 K to 333.15 K, at atmospheric pressure. The densities and viscosities of the pure ionic liquids and their mixtures with TFE were described successfully by an empirical third-order polynomial and by the Vogel–Fulcher–Tammann equation, respectively. In addition, excess molar volumes and viscosity deviations were determined from densities and viscosities of mixtures, respectively, and fitted by using the Redlich–Kister equation
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.
Angulo, Gonzalo; Brucka, Marta; Gerecke, Mario; Grampp, Günter; Jeannerat, Damien; Milkiewicz, Jadwiga; Mitrev, Yavor; Radzewicz, Czesław; Rosspeintner, Arnulf; Vauthey, Eric; Wnuk, Paweł
2016-07-21
The properties of binary mixtures of dimethylsulfoxide and glycerol, measured using 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 on 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 change with the molar fraction of glycerol. PMID:27339434