WorldWideScience

Sample records for supercooled liquid vapor

  1. Supercooled liquids for pedestrians

    Science.gov (United States)

    Cavagna, Andrea

    2009-06-01

    When we lower the temperature of a liquid, at some point we meet a first order phase transition to the crystal. Yet, under certain conditions it is possible to keep the system in its metastable phase and to avoid crystallization. In this way the liquid enters in the supercooled phase. Supercooled liquids have a very rich phenomenology, which is still far from being completely understood. To begin with, there is the problem of how to prevent crystallization and how deeply the liquid can be supercooled before a metastability limit is hit. But by far the most interesting feature of supercooled liquids is the dynamic glass transition: when the temperature is decreased below a certain point, the relaxation time increases so much that a dramatic dynamical arrest intervenes and we are unable to equilibrate the system within reasonable experimental times. The glass transition is a phenomenon whose physical origin has stirred an enormous interest in the last hundred years. Why does it occur? Is it just a conventional reference point, or does it have a more profound physical meaning? Is it a purely dynamical event, or the manifestation of a true thermodynamic transition? What is the correlation length associated to the sharp increase of the relaxation time? Can we define a new kind of amorphous order? A shared theory of supercooled liquids and the glass transition does not yet exist and these questions are still largely open. Here, I will illustrate in the most elementary fashion the main phenomenological traits of supercooled liquids and discuss in a very partial way a few theoretical ideas on the subject.

  2. Supercooled Liquids and Glasses

    OpenAIRE

    1999-01-01

    In these lectures, which were presented at "Soft and Fragile Matter, Nonequilibrium Dynamics, Metastability and Flow" University of St. Andrews, 8 July - 22 July, 1999, I give an introduction to the physics of supercooled liquids and glasses and discuss some computer simulations done to investigate these systems.

  3. Strain Pattern in Supercooled Liquids

    Science.gov (United States)

    Illing, Bernd; Fritschi, Sebastian; Hajnal, David; Klix, Christian; Keim, Peter; Fuchs, Matthias

    2016-11-01

    Investigations of strain correlations at the glass transition reveal unexpected phenomena. The shear strain fluctuations show an Eshelby-strain pattern [˜cos (4 θ ) /r2 ], characteristic of elastic response, even in liquids, at long times. We address this using a mode-coupling theory for the strain fluctuations in supercooled liquids and data from both video microscopy of a two-dimensional colloidal glass former and simulations of Brownian hard disks. We show that the long-ranged and long-lived strain signatures follow a scaling law valid close to the glass transition. For large enough viscosities, the Eshelby-strain pattern is visible even on time scales longer than the structural relaxation time τ and after the shear modulus has relaxed to zero.

  4. Entropy-driven liquid-liquid separation in supercooled water

    OpenAIRE

    Holten, V.; Anisimov, M.A.

    2012-01-01

    Twenty years ago Poole et al. (Nature 360, 324, 1992) suggested that the anomalous properties of supercooled water may be caused by a critical point that terminates a line of liquid-liquid separation of lower-density and higher-density water. Here we present an explicit thermodynamic model based on this hypothesis, which describes all available experimental data for supercooled water with better quality and with fewer adjustable parameters than any other model suggested so far. Liquid water a...

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

    Science.gov (United States)

    Tellinghuisen, Joel

    2010-01-01

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

  6. Entropy-driven liquid-liquid separation in supercooled water

    CERN Document Server

    Holten, V

    2012-01-01

    Twenty years ago Poole et al. (Nature 360, 324, 1992) suggested that the anomalous properties of supercooled water may be caused by a critical point that terminates a line of liquid-liquid separation of lower-density and higher-density water. Here we present an explicit thermodynamic model based on this hypothesis, which describes all available experimental data for supercooled water with better quality and with fewer adjustable parameters than any other model suggested so far. Liquid water at low temperatures is viewed as an 'athermal solution' of two molecular structures with different entropies and densities. Alternatively to popular models for water, in which the liquid-liquid separation is driven by energy, the phase separation in the athermal two-state water is driven by entropy upon increasing the pressure, while the critical temperature is defined by the 'reaction' equilibrium constant. In particular, the model predicts the location of density maxima at the locus of a near-constant fraction (about 0.1...

  7. Polarized View of Supercooled Liquid Water Clouds

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Van Diedenhoven, Bastiaan; Ackerman, Andrew S.; Wasilewski, Andrzej P.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven E.; Arnold, G. Thomas

    2016-01-01

    Supercooled liquid water (SLW) clouds, where liquid droplets exist at temperatures below 0 C present a well known aviation hazard through aircraft icing, in which SLW accretes on the airframe. SLW clouds are common over the Southern Ocean, and climate-induced changes in their occurrence is thought to constitute a strong cloud feedback on global climate. The two recent NASA field campaigns POlarimeter Definition EXperiment (PODEX, based in Palmdale, California, January-February 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, based in Houston, Texas in August- September 2013) provided a unique opportunity to observe SLW clouds from the high-altitude airborne platform of NASA's ER-2 aircraft. We present an analysis of measurements made by the Research Scanning Polarimeter (RSP) during these experiments accompanied by correlative retrievals from other sensors. The RSP measures both polarized and total reflectance in 9 spectral channels with wavelengths ranging from 410 to 2250 nm. It is a scanning sensor taking samples at 0.8deg intervals within 60deg from nadir in both forward and backward directions. This unique angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135deg and 165deg. Simple parametric fitting algorithms applied to the polarized reflectance provide retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT),which allows retrieval of the droplet size distribution without assuming a size distribution shape. We present an overview of the RSP campaign datasets available from the NASA GISS website, as well as two detailed examples of the retrievals. In these case studies we focus on cloud fields with spatial features

  8. Polarized View of Supercooled Liquid Water Clouds

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Van Diedenhoven, Bastiaan; Ackerman, Andrew S.; Wasilewski, Andrzej P.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven E.; Arnold, G. Thomas

    2016-01-01

    Supercooled liquid water (SLW) clouds, where liquid droplets exist at temperatures below 0 C present a well known aviation hazard through aircraft icing, in which SLW accretes on the airframe. SLW clouds are common over the Southern Ocean, and climate-induced changes in their occurrence is thought to constitute a strong cloud feedback on global climate. The two recent NASA field campaigns POlarimeter Definition EXperiment (PODEX, based in Palmdale, California, January-February 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, based in Houston, Texas in August- September 2013) provided a unique opportunity to observe SLW clouds from the high-altitude airborne platform of NASA's ER-2 aircraft. We present an analysis of measurements made by the Research Scanning Polarimeter (RSP) during these experiments accompanied by correlative retrievals from other sensors. The RSP measures both polarized and total reflectance in 9 spectral channels with wavelengths ranging from 410 to 2250 nm. It is a scanning sensor taking samples at 0.8deg intervals within 60deg from nadir in both forward and backward directions. This unique angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135deg and 165deg. Simple parametric fitting algorithms applied to the polarized reflectance provide retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT),which allows retrieval of the droplet size distribution without assuming a size distribution shape. We present an overview of the RSP campaign datasets available from the NASA GISS website, as well as two detailed examples of the retrievals. In these case studies we focus on cloud fields with spatial features

  9. Determination of octanol-air partition coefficients and supercooled liquid vapor pressures of PAHs as a function of temperature: Application to gas-particle partitioning in an urban atmosphere

    Science.gov (United States)

    Odabasi, Mustafa; Cetin, Eylem; Sofuoglu, Aysun

    Octanol-air partition coefficients ( KOA) for 14 polycyclic aromatic hydrocarbons (PAHs) were determined as a function of temperature using the gas chromatographic retention time method. log KOA values at 25° ranged over six orders of magnitude, between 6.34 (acenaphthylene) and 12.59 (dibenz[ a,h]anthracene). The determined KOA values were within factor of 0.7 (dibenz[ a,h]anthracene) to 15.1 (benz[ a]anthracene) of values calculated as the ratio of octanol-water partition coefficient to dimensionless Henry's law constant. Supercooled liquid vapor pressures ( PL) of 13 PAHs were also determined using the gas chromatographic retention time technique. Activity coefficients in octanol calculated using KOA and PL ranged between 3.2 and 6.2 indicating near-ideal solution behavior. Atmospheric concentrations measured in this study in Izmir, Turkey were used to investigate the partitioning of PAHs between particle and gas-phases. Experimental gas-particle partition coefficients ( Kp) were compared to the predictions of KOA absorption and KSA (soot-air partition coefficient) models. Octanol-based absorptive partitioning model predicted lower partition coefficients especially for relatively volatile PAHs. Ratios of measured/modeled partition coefficients ranged between 1.1 and 15.5 (4.5±6.0, average±SD) for KOA model. KSA model predictions were relatively better and measured to modeled ratios ranged between 0.6 and 5.6 (2.3±2.7, average±SD).

  10. Hopping in a supercooled binary Lennard-Jones liquid

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    1998-01-01

    A binary Lennard–Jones 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...

  11. Entropy calculations for a supercooled liquid crystalline blue phase

    Energy Technology Data Exchange (ETDEWEB)

    Singh, U [Physics Department, University of the West Indies, PO Box 64, Bridgetown (Barbados)

    2007-01-15

    We observed, using polarized light microscopy, the supercooling of the blue phase (BPI) of cholesteryl proprionate and measured the corresponding liquid crystalline phase transition temperatures. From these temperatures and additional published data we have provided, for the benefit of undergraduate physics students, a nontraditional example involving entropy calculations for an irreversible transition.

  12. On the potential energy landscape of supercooled liquids and glasses

    DEFF Research Database (Denmark)

    Rodney, D.; Schrøder, Thomas

    2011-01-01

    The activation-relaxation technique (ART), a saddle-point search method, is applied to determine the potential energy landscape around supercooled and glassy configurations of a three-dimensional binary Lennard-Jones system. We show a strong relation between the distribution of activation energies...... around a given glassy configuration and its history, in particular, the cooling rate used to produce the glass and whether or not the glass was plastically deformed prior to sampling. We also compare the thermally activated transitions found by ART around a supercooled configuration with the succession...... of transitions undergone by the same supercooled liquid during a time trajectory simulated by molecular dynamics. We find that ART is biased towards more heterogeneous transitions with higher activation energies and more broken bonds than the MD simulation....

  13. 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.

  14. Shear-accelerated crystallization in a supercooled atomic liquid.

    Science.gov (United States)

    Shao, Zhen; Singer, Jonathan P; Liu, Yanhui; Liu, Ze; Li, Huiping; Gopinadhan, Manesh; O'Hern, Corey S; Schroers, Jan; Osuji, Chinedum O

    2015-02-01

    A bulk metallic glass forming alloy is subjected to shear flow in its supercooled state by compression of a short rod to produce a flat disk. The resulting material exhibits enhanced crystallization kinetics during isothermal annealing as reflected in the decrease of the crystallization time relative to the nondeformed case. The transition from quiescent to shear-accelerated crystallization is linked to strain accumulated during shear flow above a critical shear rate γ̇(c)≈0.3 s(-1) which corresponds to Péclet number, Pe∼O(1). The observation of shear-accelerated crystallization in an atomic system at modest shear rates is uncommon. It is made possible here by the substantial viscosity of the supercooled liquid which increases strongly with temperature in the approach to the glass transition. We may therefore anticipate the encounter of nontrivial shear-related effects during thermoplastic deformation of similar systems.

  15. Hopping in a supercooled binary Lennard-Jones liquid

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    1998-01-01

    A binary Lennard–Jones 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 examine the dynamics of the system, we consider transitions between the inherent structures (local minima in the potential energy) along the trajectory. We conclude that the plateau in the mean square displacement found at lower temperatures is indeed a result of particles being trapped in local "cages...

  16. Behavior of Supercooled Aqueous Solutions Stemming from Hidden Liquid-Liquid Transition in Water

    OpenAIRE

    Biddle, John W.; Holten, Vincent; Anisimov, Mikhail A.

    2014-01-01

    A popular hypothesis that explains the anomalies of supercooled water is the existence of a metastable liquid-liquid transition hidden below the line of homogeneous nucleation. If this transition exists and if it is terminated by a critical point, the addition of a solute should generate a line of liquid-liquid critical points emanating from the critical point of pure metastable water. We have analyzed thermodynamic consequences of this scenario. In particular, we consider the behavior of two...

  17. Electrostatic levitation studies of supercooled liquids and metastable solid phases

    Science.gov (United States)

    Rustan, Gustav Errol

    A new laboratory has been developed at Iowa State University (ISU) to be used for the study of high temperature liquids and solids, with particular focus on the supercooling of liquids and their metastable solidification products. This new laboratory employs the electrostatic levitation (ESL) technique, in which a charged sample is suspended between a set of electrodes to achieve non-contact handling. Owing to the elimination of a crucible, high temperature processing of samples can be achieved with reduced levels of contamination and heterogeneous nucleation. Because of the reduction in heterogeneous nucleation, samples can be supercooled well below their equilibrium melting temperature, opening the door to a wide range of measurements on supercooled liquids. Measurements methods have been implemented for the characterization of thermophysical properties such as: volume/density, ratio of specific heat to total hemispherical emissivity, surface tension, viscosity, electrical resistivity, and magnetic susceptibility. For measurements of electrical resistivity and magnetic susceptibility, a new method has been developed at ISU based on the tunnel diode oscillator (TDO) technique. The TDO technique uses the negative differential resistance of a tunnel diode to drive an LC tank circuit into self-sustained oscillation at the resonant LC frequency. The LC tank is inductively coupled to the samples under study, and changes in the electrical resistivity or magnetic susceptibility of the sample are manifested as changes in the resonant frequency. By measuring the frequency shifts of the TDO, insights can be made into changes in the material's electrical and magnetic properties. This method has been validated by performing resistivity measurements on a sample of high purity Zr, and by performing measurements on the ferromagnetic transition in a low-carbon steel ball bearing. In addition to the development of the laboratory and its supporting instrumentation, an effort has

  18. A phase space approach to supercooled liquids and a universal collapse of their viscosity

    CERN Document Server

    Weingartner, Nicholas B; Nogueira, Flavio S; Kelton, K F; Nussinov, Zohar

    2016-01-01

    A broad fundamental understanding of the mechanisms underlying the phenomenology of supercooled liquids has remained elusive, despite decades of intense exploration. When supercooled beneath its characteristic melting temperature, a liquid sees a sharp rise in its viscosity over a narrow temperature range, eventually becoming frozen on laboratory timescales. Explaining this immense increase in viscosity is one of the principle goals of condensed matter physicists. To that end, numerous theoretical frameworks have been proposed which explain and reproduce the temperature dependence of the viscosity of supercooled liquids. Each of these frameworks appears only applicable to specific classes of glassformers and each possess a number of variable parameters. Here we describe a classical framework for explaining the dynamical behavior of supercooled liquids based on statistical mechanical considerations, and possessing only a single variable parameter. This parameter varies weakly from liquid to liquid. Furthermore...

  19. Dynamical Instability Causes the Demise of a Supercooled Tetrahedral Liquid

    Science.gov (United States)

    Gautam, Arvind Kumar; Pingua, Nandlal; Goyal, Aashish; Apte, Pankaj A.

    2017-09-01

    We investigate the relaxation mechanism of a supercooled tetrahedral liquid at its limit of stability using isothermal isobaric ( NPT) Monte Carlo simulations. In similarity with systems which are far from equilibrium but near the onset of jamming (O'Hern et al. in Phys Rev Lett 93:165702, 2004), we find that the relaxation is characterized by two time-scales: the decay of long-wavelength (slow) fluctuations of potential energy is controlled by the slope [partial (G/N)/partial φ ] of the Gibbs free energy ( G) at a unique value of per particle potential energy φ = φ _{{\\tiny mid}}. The short-wavelength (fast) fluctuations are controlled by the bath temperature T. The relaxation of the supercooled liquid is initiated with a dynamical crossover after which the potential energy fluctuations are biased towards values progressively lesser than φ _{{\\tiny mid}}. The dynamical crossover leads to the change of time-scale, i.e., the decay of long-wavelength potential energy fluctuations (intermediate stage of relaxation). Because of the condition [partial ^2 (G/N)/partial φ ^2 = 0] at φ = φ _{{\\tiny mid}}, the slope [partial (G/N)/partial φ ] has a unique value and governs the intermediate stage of relaxation, which ends just after the crossover. In the subsequent stage, there is a relatively rapid crystallization due to lack of long-wavelength fluctuations and the instability at φ _{{\\tiny mid}}, i.e., the condition that G decreases as configurations with potential energies lower than φ _{{\\tiny mid}} are accessed. The dynamical crossover point and the associated change in the time-scale of fluctuations is found to be consistent with the previous studies.

  20. Spatiotemporal heterogeneity of local free volumes in highly supercooled liquid

    Science.gov (United States)

    Shiba, Hayato; Kawasaki, Takeshi

    2013-11-01

    We discuss the spatiotemporal behavior of local density and its relation to dynamical heterogeneity in a highly supercooled liquid by using molecular dynamics simulations of a binary mixture with different particle sizes in two dimensions. To trace voids heterogeneously existing with lower local densities, which move along with the structural relaxation, we employ the minimum local density for each particle in a time window whose width is set along with the structural relaxation time. Particles subject to free volumes correspond well to the configuration rearranging region of dynamical heterogeneity. While the correlation length for dynamical heterogeneity grows with temperature decrease, no growth in the correlation length of heterogeneity in the minimum local density distribution takes place. A comparison of these results with those of normal mode analysis reveals that superpositions of lower-frequency soft modes extending over the free volumes exhibit spatial correlation with the broken bonds. This observation suggests a possibility that long-ranged vibration modes facilitate the interactions between fragile regions represented by free volumes, to induce dynamical correlations at a large scale.

  1. A phase space approach to supercooled liquids and a universal collapse of their viscosity

    Directory of Open Access Journals (Sweden)

    Nicholas Bryan Weingartner

    2016-11-01

    Full Text Available A broad fundamental understanding of the mechanisms underlying the phenomenology of supercooled liquids has remained elusive, despite decades of intense exploration. When supercooled beneath its characteristic melting temperature, a liquid sees a sharp rise in its viscosity over a narrow temperature range, eventually becoming frozen on laboratory timescales. Explaining this immense increase in viscosity is one of the principle goals of condensed matter physicists. To that end, numerous theoretical frameworks have been proposed which explain and reproduce the temperature dependence of the viscosity of supercooled liquids. Each of these frameworks appears only applicable to specific classes of glassformers and each possess a number of variable parameters. Here we describe a classical framework for explaining the dynamical behavior of supercooled liquids based on statistical mechanical considerations, and possessing only a single variable parameter. This parameter varies weakly from liquid to liquid. Furthermore, as predicted by this new classical theory and its earlier quantum counterpart, we find with the aid of a small dimensionless constant that varies in size from sim 0.05-0.12 , a universal (16 decade collapse of the viscosity data as a function of temperature. The collapse appears in all known types of glass forming supercooled liquids (silicates, metallic alloys, organic systems, chalcogenide, sugars, and water.

  2. A phase space approach to supercooled liquids and a universal collapse of their viscosity

    Science.gov (United States)

    Weingartner, Nicholas; Nogueira, Flavio; Pueblo, Chris; Kelton, Kenneth; Nussinov, Zohar

    2016-11-01

    A broad fundamental understanding of the mechanisms underlying the phenomenology of supercooled liquids has remained elusive, despite decades of intense exploration. When supercooled beneath its characteristic melting temperature, a liquid sees a sharp rise in its viscosity over a narrow temperature range, eventually becoming frozen on laboratory timescales. Explaining this immense increase in viscosity is one of the principle goals of condensed matter physicists. To that end, numerous theoretical frameworks have been proposed which explain and reproduce the temperature dependence of the viscosity of supercooled liquids. Each of these frameworks appears only applicable to specific classes of glassformers and each possess a number of variable parameters. Here we describe a classical framework for explaining the dynamical behavior of supercooled liquids based on statistical mechanical considerations, and possessing only a single variable parameter. This parameter varies weakly from liquid to liquid. Furthermore, as predicted by this new classical theory and its earlier quantum counterpart, we find with the aid of a small dimensionless constant that varies in size from ˜ 0.05-0.12, a universal (16 decade) collapse of the viscosity data as a function of temperature. The collapse appears in all known types of glass forming supercooled liquids (silicates, metallic alloys, organic systems, chalcogenide, sugars, and water).

  3. Behavior of supercooled aqueous solutions stemming from hidden liquid-liquid transition in water

    Science.gov (United States)

    Biddle, John W.; Holten, Vincent; Anisimov, Mikhail A.

    2014-08-01

    A popular hypothesis that explains the anomalies of supercooled water is the existence of a metastable liquid-liquid transition hidden below the line of homogeneous nucleation. If this transition exists and if it is terminated by a critical point, the addition of a solute should generate a line of liquid-liquid critical points emanating from the critical point of pure metastable water. We have analyzed thermodynamic consequences of this scenario. In particular, we consider the behavior of two systems, H2O-NaCl and H2O-glycerol. We find the behavior of the heat capacity in supercooled aqueous solutions of NaCl, as reported by Archer and Carter [J. Phys. Chem. B 104, 8563 (2000)], to be consistent with the presence of the metastable liquid-liquid transition. We elucidate the non-conserved nature of the order parameter (extent of "reaction" between two alternative structures of water) and the consequences of its coupling with conserved properties (density and concentration). We also show how the shape of the critical line in a solution controls the difference in concentration of the coexisting liquid phases.

  4. Liquid-liquid transition in supercooled water suggested by microsecond simulations.

    Science.gov (United States)

    Li, Yaping; Li, Jicun; Wang, Feng

    2013-07-23

    The putative liquid-liquid phase transition in supercooled water has been used to explain many anomalous behaviors of water. However, no direct experimental verification of such a phase transition has been accomplished, and theoretical studies from different simulations contradict each other. We investigated the putative liquid-liquid phase transition using the Water potential from Adaptive Force Matching for Ice and Liquid (WAIL). The simulation reveals a first-order phase transition in the supercooled regime with the critical point at ~207 K and 50 MPa. Normal water is high-density liquid (HDL). Low-density liquid (LDL) emerges at lower temperatures. The LDL phase has a density only slightly larger than that of the ice-Ih and shows more long-range order than HDL. However, the transformation from LDL to HDL is spontaneous across the first-order phase transition line, suggesting the LDL configuration is not poorly formed nanocrystalline ice. It has been demonstrated in the past that the WAIL potential provides reliable predictions of water properties such as melting temperature and temperature of maximum density. Compared with other simple water potentials, WAIL is not biased by fitting to experimental properties, and simulation with this potential reflects the prediction of a high-quality first-principle potential energy surface.

  5. Orientational dynamics and energy landscape features of thermotropic liquid crystals: An analogy with supercooled liquids

    Indian Academy of Sciences (India)

    Biman Jana; Biman Bagchi

    2007-09-01

    Recent optical kerr effect (OKE) studies have revealed that orientational relaxation of rodlike nematogens near the isotropic-nematic (I-N) phase boundary and also in the nematic phase exhibit temporal power law decay at intermediate times. Such behaviour has drawn an intriguing analogy with supercooled liquids. Here, we have investigated the single-particle and collective orientational dynamics of a family of model system of thermotropic liquid crystals using extensive computer simulations. Several remarkable features of glassy dynamics are on display including non-exponential relaxation, dynamical heterogeneity, and non-Arrhenius temperature dependence of the orientational relaxation time. Over a temperature range near the I-N phase boundary, the system behaves like a fragile glass-forming liquid. Using proper scaling, we construct the usual relaxation time versus inverse temperature plot and explicitly demonstrate that one can successfully define a density dependent fragility of liquid crystals. The fragility of liquid crystals shows a temperature and density dependence which is remarkably similar to the fragility of glass forming supercooled liquids. Energy landscape analysis of inherent structures shows that the breakdown of the Arrhenius temperature dependence of relaxation rate occurs at a temperature that marks the onset of the growth of the depth of the potential energy minima explored by the system.

  6. Radiometric Observations of Supercooled Liquid Water within a Split Front over the Sierra Nevada.

    Science.gov (United States)

    Heggli, Mark F.; Reynolds, David W.

    1985-11-01

    A storm bearing close structural resemblance to a katafront was observed from the ground with microwave radiometry and a vertically pointing Ka-band radar over the Sierra Nevada of California. The onset and duration of supercooled liquid water was determined and matched to a split front model used to describe the synoptic features of a katafront. Results indicate that prior to the passage of the upper front no supercooled liquid water was observed. This portion of the storm provided the deepest cloud and coldest cloud tops. Supercooled liquid water was most prevalent after the upper front passage, and persisted until the suspected surface front passage. The duration of measured supercooled water was 16 hours.This information broadens the knowledge regarding the presence of supercooled liquid water, and thus possible seeding potential, within winter storms so that treatment can be confined to the period of storms amenable to cloud seeding. Future studies may well confirm the ease with which these periods can be predicted on an operational basis in the Sierra Nevada.

  7. Experimental evidence for supercooled brines, viscous liquids, and low temperature perchlorate glasses on Mars

    Science.gov (United States)

    Toner, J.; Catling, D. C.; Light, B.

    2013-12-01

    The presence of liquid water on the cold and dry surface of Mars is possible where concentrated salt solutions lower the freezing point of water. The eutectic temperature is the maximum equilibrium freezing point depression possible for a given salt solution, which ranges from near 0°C for carbonates and sulfates, to as low as -75°C for perchlorates. Although eutectic temperatures suggest a lower temperature limit for liquid water on Mars, salt solutions will typically supercool below their eutectic before crystallization occurs. We report on results investigating the magnitude of supercooling and its variation with salt composition and concentration for pure salt solutions and saturated soil solutions of MgSO4, MgCl2, NaCl, NaClO4, Mg(ClO4)2, and Ca(ClO4)2. We measured supercooling by monitoring solution temperatures during slow cooling and warming experiments. Our results indicate that supercooling is pervasive. Slowly cooled MgSO4, MgCl2, NaCl, and NaClO4 solutions typically supercool 5-15°C below their eutectic temperature before crystallizing. The addition of soil to these salt solutions has a variable effect on supercooling. Relative to the pure salt solutions, supercooling decreases in MgSO4 soil solutions, increases in MgCl2 soil solutions, and is similar in NaCl and NaClO4 soil solutions. Supercooling in MgSO4, MgCl2, NaCl, and NaClO4 solutions could marginally extend the duration of liquid water during relatively warm daytime temperatures in the Martian summer. Remarkably, we found that Mg(ClO4)2 and Ca(ClO4)2 solutions never crystallize during slow cooling, but remain in a supercooled, liquid state until forming an amorphous glass near -120°C. Even if soil is added to the solutions, which will induce crystallization in most salt solutions, a glass still forms during cooling. The large supercooling effect in Mg(ClO4)2 and Ca(ClO4)2 solutions has the potential to prevent water from freezing over diurnal and possibly annual cycles on Mars. Glasses are

  8. Structural crossover in a supercooled metallic liquid and the link to a liquid-to-liquid phase transition

    Science.gov (United States)

    Lan, S.; Blodgett, M.; Kelton, K. F.; Ma, J. L.; Fan, J.; Wang, X.-L.

    2016-05-01

    Time-resolved synchrotron measurements were carried out to capture the structure evolution of an electrostatically levitated metallic-glass-forming liquid during free cooling. The experimental data shows a crossover in the liquid structure at ˜1000 K, about 115 K below the melting temperature and 150 K above the crystallization temperature. The structure change is characterized by a dramatic growth in the extended-range order below the crossover temperature. Molecular dynamics simulations have identified that the growth of the extended-range order was due to an increased correlation between solute atoms. These results provide structural evidence for a liquid-to-liquid-phase-transition in the supercooled metallic liquid.

  9. Liquid–liquid transition in supercooled water suggested by microsecond simulations

    OpenAIRE

    Li, Yaping; Li, Jicun; Wang, Feng

    2013-01-01

    The putative liquid–liquid phase transition in supercooled water has been used to explain many anomalous behaviors of water. However, no direct experimental verification of such a phase transition has been accomplished, and theoretical studies from different simulations contradict each other. We investigated the putative liquid–liquid phase transition using the Water potential from Adaptive Force Matching for Ice and Liquid (WAIL). The simulation reveals a first-order phase transition in the ...

  10. Thermalization calorimetry: A simple method for investigating glass transition and crystallization of supercooled liquids

    DEFF Research Database (Denmark)

    Jakobsen, Bo; Sanz, Alejandro; Niss, Kristine;

    2016-01-01

    We present a simple method for fast and cheap thermal analysis on supercooled glass-forming liquids. This “Thermalization Calorimetry” technique is based on monitoring the temperature and its rate of change during heating or cooling of a sample for which the thermal power input comes from heat...

  11. A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuntao [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Dibble, Collin J. [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Petrik, Nikolay G. [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Smith, R. Scott [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Joly, Alan G. [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Tonkyn, Russell G. [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Kay, Bruce D. [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA; Kimmel, Greg A. [Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA

    2016-04-26

    A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond timescale in ultrahigh vacuum (UHV). Details of the design, implementation and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ~1010 K/s for temperature increases of ~100 – 200 K are obtained. Subsequent rapid cooling (~5 × 109 K/s) quenches the film, permitting in-situ, post-mortem analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ~ ± 3% leading to a temperature uncertainty of ~ ± 5 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.

  12. Dynamics of supercooled liquid and plastic crystalline ethanol: Dielectric relaxation and AC nanocalorimetry distinguish structural α- and Debye relaxation processes

    Science.gov (United States)

    Chua, Y. Z.; Young-Gonzales, A. R.; Richert, R.; Ediger, M. D.; Schick, C.

    2017-07-01

    Physical vapor deposition has been used to prepare glasses of ethanol. Upon heating, the glasses transformed into the supercooled liquid phase and then crystallized into the plastic crystal phase. The dynamic glass transition of the supercooled liquid is successfully measured by AC nanocalorimetry, and preliminary results for the plastic crystal are obtained. The frequency dependences of these dynamic glass transitions observed by AC nanocalorimetry are in disagreement with conclusions from previously published dielectric spectra of ethanol. Existing dielectric loss spectra have been carefully re-evaluated considering a Debye peak, which is a typical feature in the dielectric loss spectra of monohydroxy alcohols. The re-evaluated dielectric fits reveal a prominent dielectric Debye peak, a smaller and asymmetrically broadened peak, which is identified as the signature of the structural α-relaxation and a Johari-Goldstein secondary relaxation process. This new assignment of the dielectric processes is supported by the observation that the AC nanocalorimetry dynamic glass transition temperature, Tα, coincides with the dielectric structural α-relaxation process rather than the Debye process. The combined results from dielectric spectroscopy and AC nanocalorimetry on the plastic crystal of ethanol suggest the occurrence of a Debye process also in the plastic crystal phase.

  13. Mechanical responses and stress fluctuations of a supercooled liquid in a sheared non-equilibrium state.

    Science.gov (United States)

    Mizuno, H; Yamamoto, R

    2012-04-01

    A steady shear flow can drive supercooled liquids into a non-equilibrium state. Using molecular dynamics simulations under steady shear flow superimposed with oscillatory shear strain for a probe, non-equilibrium mechanical responses are studied for a model supercooled liquid composed of binary soft spheres. We found that even in the strongly sheared situation, the supercooled liquid exhibits surprisingly isotropic responses to oscillating shear strains applied in three different components of the strain tensor. Based on this isotropic feature, we successfully constructed a simple two-mode Maxwell model that can capture the key features of the storage and loss moduli, even for highly non-equilibrium state. Furthermore, we examined the correlation functions of the shear stress fluctuations, which also exhibit isotropic relaxation behaviors in the sheared non-equilibrium situation. In contrast to the isotropic features, the supercooled liquid additionally demonstrates anisotropies in both its responses and its correlations to the shear stress fluctuations. Using the constitutive equation (a two-mode Maxwell model), we demonstrated that the anisotropic responses are caused by the coupling between the oscillating strain and the driving shear flow. Due to these anisotropic responses and fluctuations, the violation of the fluctuation-dissipation theorem (FDT) is distinct for different components. We measured the magnitude of this violation in terms of the effective temperature. It was demonstrated that the effective temperature is notably different between different components, which indicates that a simple scalar mapping, such as the concept of an effective temperature, oversimplifies the true nature of supercooled liquids under shear flow. An understanding of the mechanism of isotropies and anisotropies in the responses and fluctuations will lead to a better appreciation of these violations of the FDT, as well as certain consequent modifications to the concept of an

  14. Liquid Supercoolability and Synthesis Kinetics of Quinary Refractory High-entropy Alloy

    Science.gov (United States)

    Wang, W. L.; Hu, L.; Yang, S. J.; Wang, A.; Wang, L.; Wei, B.

    2016-11-01

    The high-entropy configuration of equiatomic multicomponent alloys opens an effective access to the development of advanced materials. Here we report the synthesis of a new quinary refractory WMoTaNbZr high-entropy alloy under electrostatic levitation condition. It showed a high liquidus temperature of 2686 K and achieved a maximum supercooling of 640 K (0.24 TL) at molten state. The containerless measurements revealed a linear increasing tendency for both its liquid state density and the specific heat to emissivity ratio versus alloy supercooling. A high-entropy body-centered cubic (HEB) phase dominated its phase constitution despite the formation of a negligible amount of solid solution (Zr) phase. The dendritic growth of HEB phase always governed the crystallization process, attained a fastest growth velocity of 13.5 m/s and displayed a power function relation to alloy supercooling. The high speed videographic research of recalescence phenomenon indicated Johnson-Mehl-Avrami type transition kinetics for its rapid solidification process. As supercooling increases, the microstructures of primary HEB phase were refined conspicuously and exhibited an obvious solute trapping effect of the segregative Zr component. Meanwhile, the Vickers hardness of HEB phase displayed the rising tendency with supercooling.

  15. Thermal conductivity of supercooled water.

    Science.gov (United States)

    Biddle, John W; Holten, Vincent; Sengers, Jan V; Anisimov, Mikhail A

    2013-04-01

    The heat capacity of supercooled water, measured down to -37°C, shows an anomalous increase as temperature decreases. The thermal diffusivity, i.e., the ratio of the thermal conductivity and the heat capacity per unit volume, shows a decrease. These anomalies may be associated with a hypothesized liquid-liquid critical point in supercooled water below the line of homogeneous nucleation. However, while the thermal conductivity is known to diverge at the vapor-liquid critical point due to critical density fluctuations, the thermal conductivity of supercooled water, calculated as the product of thermal diffusivity and heat capacity, does not show any sign of such an anomaly. We have used mode-coupling theory to investigate the possible effect of critical fluctuations on the thermal conductivity of supercooled water and found that indeed any critical thermal-conductivity enhancement would be too small to be measurable at experimentally accessible temperatures. Moreover, the behavior of thermal conductivity can be explained by the observed anomalies of the thermodynamic properties. In particular, we show that thermal conductivity should go through a minimum when temperature is decreased, as Kumar and Stanley observed in the TIP5P model of water. We discuss physical reasons for the striking difference between the behavior of thermal conductivity in water near the vapor-liquid and liquid-liquid critical points.

  16. Breaking Through the Glass Ceiling: Recent Experimental Approaches to Probe the Properties of Supercooled Liquids near the Glass Transition.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R. Scott; Kay, Bruce D.

    2012-03-15

    Experimental measurements of the properties supercooled liquids at temperatures near their respective glass transition temperatures, Tg, are requisite for understanding the behavior of glasses and amorphous solids. Unfortunately, many supercooled molecular liquids rapidly crystallize at temperatures far above their Tg making such measurements difficult to nearly impossible. In this perspective we discuss some recent alternative approaches to obtain experimental data in the temperature regime near Tg. These new approaches may yield the additional experimental data necessary to test current theoretical models of the dynamical slowdown that occurs in supercooled liquids approaching the glass transition.

  17. Breaking Through the Glass Ceiling: Recent Experimental Approaches to Probe the Properties of Supercooled Liquids near the Glass Transition.

    Science.gov (United States)

    Smith, R Scott; Kay, Bruce D

    2012-03-15

    Experimental measurements of the properties of supercooled liquids at temperatures near their glass transition temperatures, Tg, are requisite for understanding the behavior of glasses and amorphous solids. Unfortunately, many supercooled molecular liquids rapidly crystallize at temperatures far above their Tg, making such measurements difficult to nearly impossible. In this Perspective, we discuss some recent alternative approaches to obtain experimental data in the temperature regime near Tg. These new approaches may yield the additional experimental data necessary to test current theoretical models of the dynamical slowdown that occurs in supercooled liquids approaching the glass transition.

  18. Thermalization calorimetry: A simple method for investigating glass transition and crystallization of supercooled liquids

    Directory of Open Access Journals (Sweden)

    Bo Jakobsen

    2016-05-01

    Full Text Available We present a simple method for fast and cheap thermal analysis on supercooled glass-forming liquids. This “Thermalization Calorimetry” technique is based on monitoring the temperature and its rate of change during heating or cooling of a sample for which the thermal power input comes from heat conduction through an insulating material, i.e., is proportional to the temperature difference between sample and surroundings. The monitored signal reflects the sample’s specific heat and is sensitive to exo- and endothermic processes. The technique is useful for studying supercooled liquids and their crystallization, e.g., for locating the glass transition and melting point(s, as well as for investigating the stability against crystallization and estimating the relative change in specific heat between the solid and liquid phases at the glass transition.

  19. Pressure Induced Liquid-to-Liquid Transition in Zr-based Supercooled Melts and Pressure Quenched Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Dmowski, W.; Gierlotka, S.; Wang, Z.; Yokoyama, Y.; Palosz, B.; Egami, T.

    2017-07-26

    Through high-energy x-ray diffraction and atomic pair density function analysis we find that Zr-based metallic alloy, heated to the supercooled liquid state under hydrostatic pressure and then quenched to room temperature, exhibits a distinct glassy structure. The PDF indicates that the Zr-Zr distances in this glass are significantly reduced compared to those quenched without pressure. Annealing at the glass transition temperature at ambient pressure reverses structural changes and the initial glassy state is recovered. This result suggests that pressure causes a liquid-to-liquid phase transition in this metallic alloy supercooled melt. Such a pressure induced transition is known for covalent liquids, but has not been observed for metallic liquids. The High Pressure Quenched glasses are stable in ambient conditions after decompression.

  20. Boson peak, Ioffe-Regel Crossover, and Liquid-Liquid phase transition in Supercooled Water

    Science.gov (United States)

    Kumar, Pradeep

    We have investigated the onset of Boson peak in a model of liquid water which exhibits a clear first-order phase transition between a low-density liquid phase and a high-density liquid phase of water at low temperature and high pressure. We find that the at low pressures, the onset of Boson peak coincides with the Widom-line of the system. At high pressures, the onset occurs at the transition temperature between the two liquids. Furthermore, we show that at both low and high pressure, the frequency of the Boson peak coincides with the Ioffe-Regel crossover of the transverse phonons, suggesting that the breakdown of Debye behavior is a general feature of Ioffe-Regel limit crossover in supercooled water. The frequency of the Boson peak is weakly pressure dependent and decreases with increasing pressure. Our work bridges gap between the experimental results on the Boson peak nanoconfined water and the behavior that one would expect from a bulk system.

  1. Liquid-liquid coexistence and crystallization in supercooled ST2 water

    Science.gov (United States)

    Martelli, Fausto; Palmer, Jeremy; Debenedetti, Pablo; Car, Roberto

    2014-03-01

    We have computed the free energy landscape of ST2 water in the supercooled regime (228.6 K and 2.4 kbar) using several state-of-the-art computational techniques, including umbrella sampling and metadynamics. Such results conclusively demonstrate coexistence between two liquid phases, a high-density liquid (HDL) and a low-density liquid (HDL), which are metastable with respect to cubic ice. We show that the three phases have distinct structural features characterized by the local structure index and ring statistics. We also find that ice nucleation, should it occur, does so from the low-density liquid. Interestingly, we find that the number of 6-member rings increases monotonically along the path from HDL to LDL, while non-monotonic behavior is observed near the saddle point along the LDL-ice Ic path. This behavior indicates a complex re-arrangement of the H-bond network, followed by progressive crystallization. DOE: DE-SC0008626 (F. M. and R.C.)

  2. Self-aggregation of vapor-liquid phase transition

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The concept of the molecular free path is introduced to derive a criterion distinguishing active molecules from inactive molecules in liquid phase. Based on molecular self-aggregation theory a concept of the critical aggregation concentration (CAC) of active molecules is proposed to describe the physical configuration before the formation of the nuclei in the process of vapor-liquid phase transition. All active molecules exist in the form of the monomer when the concentration of active molecules is lower than CAC, while the active molecules will generate aggregation once the concentration of the active molecules reaches CAC. However, these aggregates with the aggregation number N smaller than 5 can steadily exist in bulk phase. The other excess active molecules can only produce infinite aggregation and form a critical nucleus of vapor-liquid phase transition. Without outer perturbation the state point of CAC corresponds to the critical superheated or supercooled state in the process of vapor-liquid phase transition. With the aggregate property, the interfacial tension between the bulk phase and the tiny new phase is predicted and a correction is made for the classical nucleation rate in a quite good agreement with experimental results.

  3. A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum.

    Science.gov (United States)

    Xu, Yuntao; Dibble, Collin J; Petrik, Nikolay G; Smith, R Scott; Joly, Alan G; Tonkyn, Russell G; Kay, Bruce D; Kimmel, Greg A

    2016-04-28

    A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond time scale in ultrahigh vacuum (UHV). Details of the design, implementation, and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ∼10(10) K/s for temperature increases of ∼100-200 K are obtained. Subsequent rapid cooling (∼5 × 10(9) K/s) quenches the film, permitting in-situ, post-heating analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ∼±2.7% leading to a temperature uncertainty of ∼±4.4 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.

  4. A nanosecond pulsed laser heating system for studying liquid and supercooled liquid films in ultrahigh vacuum

    Science.gov (United States)

    Xu, Yuntao; Dibble, Collin J.; Petrik, Nikolay G.; Smith, R. Scott; Joly, Alan G.; Tonkyn, Russell G.; Kay, Bruce D.; Kimmel, Greg A.

    2016-04-01

    A pulsed laser heating system has been developed that enables investigations of the dynamics and kinetics of nanoscale liquid films and liquid/solid interfaces on the nanosecond time scale in ultrahigh vacuum (UHV). Details of the design, implementation, and characterization of a nanosecond pulsed laser system for transiently heating nanoscale films are described. Nanosecond pulses from a Nd:YAG laser are used to rapidly heat thin films of adsorbed water or other volatile materials on a clean, well-characterized Pt(111) crystal in UHV. Heating rates of ˜1010 K/s for temperature increases of ˜100-200 K are obtained. Subsequent rapid cooling (˜5 × 109 K/s) quenches the film, permitting in-situ, post-heating analysis using a variety of surface science techniques. Lateral variations in the laser pulse energy are ˜±2.7% leading to a temperature uncertainty of ˜±4.4 K for a temperature jump of 200 K. Initial experiments with the apparatus demonstrate that crystalline ice films initially held at 90 K can be rapidly transformed into liquid water films with T > 273 K. No discernable recrystallization occurs during the rapid cooling back to cryogenic temperatures. In contrast, amorphous solid water films heated below the melting point rapidly crystallize. The nanosecond pulsed laser heating system can prepare nanoscale liquid and supercooled liquid films that persist for nanoseconds per heat pulse in an UHV environment, enabling experimental studies of a wide range of phenomena in liquids and at liquid/solid interfaces.

  5. Real-time observation of the isothermal crystallization kinetics in a deeply supercooled liquid

    Science.gov (United States)

    Zanatta, M.; Cormier, L.; Hennet, L.; Petrillo, C.; Sacchetti, F.

    2017-01-01

    Below the melting temperature Tm, crystals are the stable phase of typical elemental or molecular systems. However, cooling down a liquid below Tm, crystallization is anything but inevitable. The liquid can be supercooled, eventually forming a glass below the glass transition temperature Tg. Despite their long lifetimes and the presence of strong barriers that produces an apparent stability, supercooled liquids and glasses remain intrinsically a metastable state and thermodynamically unstable towards the crystal. Here we investigated the isothermal crystallization kinetics of the prototypical strong glassformer GeO2 in the deep supercooled liquid at 1100 K, about half-way between Tm and Tg. The crystallization process has been observed through time-resolved neutron diffraction for about three days. Data show a continuous reorganization of the amorphous structure towards the alpha-quartz phase with the final material composed by crystalline domains plunged into a low-density, residual amorphous matrix. A quantitative analysis of the diffraction patterns allows determining the time evolution of the relative fractions of crystal and amorphous, that was interpreted through an empirical model for the crystallization kinetics. This approach provides a very good description of the experimental data and identifies a predator-prey-like mechanism between crystal and amorphous, where the density variation acts as a blocking barrier. PMID:28255173

  6. Evidence of the existence of the low-density liquid phase in supercooled, confined water

    OpenAIRE

    Mallamace, Francesco; Broccio, Matteo; Corsaro, Carmelo; Faraone, Antonio; Majolino, Domenico; Venuti, Valentina; Liu, Li; Mou, Chung-Yuan; Chen, Sow-Hsin

    2006-01-01

    By confining water in a nanoporous structure so narrow that the liquid could not freeze, it is possible to study properties of this previously undescribed system well below its homogeneous nucleation temperature TH = 231 K. Using this trick, we were able to study, by means of a Fourier transform infrared spectroscopy, vibrational spectra (HOH bending and OH-stretching modes) of deeply supercooled water in the temperature range 183 < T < 273 K. We observed, upon decreasing temperature, the bui...

  7. Direct measurement of the surface dynamics of supercooled liquid-glycerol by optical scanning a film

    Institute of Scientific and Technical Information of China (English)

    Zhang Fang; Zhang Guo-Feng; Dong Shuang-Li; Sun Jian-Hu; Chen Rui-Yun; Xiao Lian-Tuan; Jia Suo-Tang

    2009-01-01

    The surface dynamics of supercooled liquid-glycerol is studied by scanning the thickness of the glycerol film with single photon detection. Measurements are performed at room temperature well above the glycerol's glass transition temperature. It is shown that the surface dynamics of the glycerol film is very sensitive to the temperature. The linear relationship between the thickness of the film and the viscosity predicted by the Vogel-Fulcher-Tammann-Hesse (VFTH) law is also presented experimentally.

  8. In-situ High-energy X-ray Diffraction Study of the Local Structure of Supercooled Liquid Si

    Science.gov (United States)

    Lee, G. W.; Kim, T. H.; Sieve, B.; Gangopadhyay, A. K.; Hyers, R. W.; Rathz, T. J.; Rogers, J. R.; Robinson, D. S.; Kelton, K. F.; Goldman, A. I.

    2005-01-01

    While changes in the coordination number for liquid silicon upon supercooling, signaling an underlying liquid-liquid phase transition, have been predicted, x-ray and neutron measurements have produced conflicting reports. In particular some studies have found an increase in the first shell coordination as temperature decreases in the supercooled regime, while others have reported increases in the coordination number with decreasing temperature. Employing the technique of electrostatic levitation coupled with high energy x-ray diffraction (125 keV), and rapid data acquisition (100ms collection times) using an area detector, we have obtained high quality structural data more deeply into the supercooled regime than has been possible before. No change in coordination number is observed in this temperature region, calling into question previous experimental claims of structural evidence for the existence of a liquid-liquid phase transition.

  9. Evidence of the existence of the low-density liquid phase in supercooled, confined water.

    Science.gov (United States)

    Mallamace, Francesco; Broccio, Matteo; Corsaro, Carmelo; Faraone, Antonio; Majolino, Domenico; Venuti, Valentina; Liu, Li; Mou, Chung-Yuan; Chen, Sow-Hsin

    2007-01-09

    By confining water in a nanoporous structure so narrow that the liquid could not freeze, it is possible to study properties of this previously undescribed system well below its homogeneous nucleation temperature TH = 231 K. Using this trick, we were able to study, by means of a Fourier transform infrared spectroscopy, vibrational spectra (HOH bending and OH-stretching modes) of deeply supercooled water in the temperature range 183 < T < 273 K. We observed, upon decreasing temperature, the building up of a new population of hydrogen-bonded oscillators centered around 3,120 cm(-1), the contribution of which progressively dominates the spectra as one enters into the deeply supercooled regime. We determined that the fractional weight of this spectral component reaches 50% just at the temperature, TL approximately 225 K, where the confined water shows a fragile-to-strong dynamic cross-over phenomenon [Ito, K., Moynihan, C. T., Angell, C. A. (1999) Nature 398:492-494]. Furthermore, the fact that the corresponding OH stretching spectral peak position of the low-density-amorphous solid water occurs exactly at 3,120 cm(-1) [Sivakumar, T. C., Rice, S. A., Sceats, M. G. (1978) J. Chem. Phys. 69:3468-3476.] strongly suggests that these oscillators originate from existence of the low-density-liquid phase derived from the occurrence of the first-order liquid-liquid (LL) phase transition and the associated LL critical point in supercooled water proposed earlier by a computer molecular dynamics simulation [Poole, P. H., Sciortino, F., Essmann, U., Stanley, H. E. (1992) Nature 360:324-328].

  10. Behavior of supercooled aqueous solutions stemming from hidden liquid–liquid transition in water

    Energy Technology Data Exchange (ETDEWEB)

    Biddle, John W.; Holten, Vincent; Anisimov, Mikhail A., E-mail: anisimov@umd.edu [Institute for Physical Science and Technology and Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2014-08-21

    A popular hypothesis that explains the anomalies of supercooled water is the existence of a metastable liquid–liquid transition hidden below the line of homogeneous nucleation. If this transition exists and if it is terminated by a critical point, the addition of a solute should generate a line of liquid–liquid critical points emanating from the critical point of pure metastable water. We have analyzed thermodynamic consequences of this scenario. In particular, we consider the behavior of two systems, H{sub 2}O-NaCl and H{sub 2}O-glycerol. We find the behavior of the heat capacity in supercooled aqueous solutions of NaCl, as reported by Archer and Carter [J. Phys. Chem. B 104, 8563 (2000)], to be consistent with the presence of the metastable liquid–liquid transition. We elucidate the non-conserved nature of the order parameter (extent of “reaction” between two alternative structures of water) and the consequences of its coupling with conserved properties (density and concentration). We also show how the shape of the critical line in a solution controls the difference in concentration of the coexisting liquid phases.

  11. Stable glass transformation to supercooled liquid via surface-initiated growth front.

    Science.gov (United States)

    Swallen, Stephen F; Traynor, Katherine; McMahon, Robert J; Ediger, M D; Mates, Thomas E

    2009-02-13

    Highly stable glasses of tris-naphthylbenzene transform into a liquid when annealed above the glass transition temperature T_{g}. In contrast to the predictions of standard models, the observed transformation is spatially inhomogeneous. Secondary ion mass spectrometry experiments on isotopically labeled multilayer films show that the liquid grows into the stable glass with sharp growth fronts initiated at the free surface and at the interface with the substrate. For the free surface, the growth velocity is constant in time and has the same temperature dependence as self-diffusion in the equilibrium supercooled liquid. These stable glasses are packed so efficiently that surfaces and interfaces are required to initiate the transformation to the liquid even well above T_{g}.

  12. Optical Kerr effect of liquid and supercooled water: The experimental and data analysis perspective

    Science.gov (United States)

    Taschin, A.; Bartolini, P.; Eramo, R.; Righini, R.; Torre, R.

    2014-08-01

    The time-resolved optical Kerr effect spectroscopy (OKE) is a powerful experimental tool enabling accurate investigations of the dynamic phenomena in molecular liquids. We introduced innovative experimental and fitting procedures, that enable a safe deconvolution of sample response function from the instrumental function. This is a critical issue in order to measure the dynamics of liquid water. We report OKE data on water measuring intermolecular vibrations and the structural relaxation processes in an extended temperature range, inclusive of the supercooled states. The unpreceded data quality makes possible a solid comparison with few theoretical models: the multi-mode Brownian oscillator model, the Kubo's discrete random jump model, and the schematic mode-coupling model. All these models produce reasonable good fits of the OKE data of stable liquid water, i.e., over the freezing point. The features of water dynamics in the OKE data becomes unambiguous only at lower temperatures, i.e., for water in the metastable supercooled phase. We found that the schematic mode-coupling model provides the more rigorous and complete model for water dynamics, even if its intrinsic hydrodynamic approach does not give a direct access to the molecular information.

  13. The formation of supercooled brines, viscous liquids, and low-temperature perchlorate glasses in aqueous solutions relevant to Mars

    Science.gov (United States)

    Toner, J. D.; Catling, D. C.; Light, B.

    2014-05-01

    Salt solutions on Mars can stabilize liquid water at low temperatures by lowering the freezing point of water. The maximum equilibrium freezing-point depression possible, known as the eutectic temperature, suggests a lower temperature limit for liquid water on Mars; however, salt solutions can supercool below their eutectic before crystallization occurs. To investigate the magnitude of supercooling and its variation with salt composition and concentration, we performed slow cooling and warming experiments on pure salt solutions and saturated soil-solutions of MgSO4, MgCl2, NaCl, NaClO4, Mg(ClO4)2, and Ca(ClO4)2. By monitoring solution temperatures, we identified exothermic crystallization events and determined the composition of precipitated phases from the eutectic melting temperature. Our results indicate that supercooling is pervasive. In general, supercooling is greater in more concentrated solutions and with salts of Ca and Mg. Slowly cooled MgSO4, MgCl2, NaCl, and NaClO4 solutions investigated in this study typically supercool 5-15 °C below their eutectic temperature before crystallizing. The addition of soil to these salt solutions has a variable effect on supercooling. Relative to the pure salt solutions, supercooling decreases in MgSO4 soil-solutions, increases in MgCl2 soil-solutions, and is similar in NaCl and NaClO4 soil-solutions. Supercooling in MgSO4, MgCl2, NaCl, and NaClO4 solutions could marginally extend the duration of liquid water during relatively warm daytime temperatures in the martian summer. In contrast, we find that Mg(ClO4)2 and Ca(ClO4)2 solutions do not crystallize during slow cooling, but remain in a supercooled, liquid state until forming an amorphous glass near -120 °C. Even if soil is added to the solutions, a glass still forms during cooling. The large supercooling effect in Mg(ClO4)2 and Ca(ClO4)2 solutions has the potential to prevent water from freezing over diurnal and possibly annual cycles on Mars. Glasses are also

  14. Using Peltier cells to study solid-liquid-vapour transitions and supercooling

    Energy Technology Data Exchange (ETDEWEB)

    Torzo, Giacomo [ICIS-CNR and Physics Department of Padova University, Padova (Italy); Soletta, Isabella [Liceo Scientifico Fermi, Alghero (Italy); Branca, Mario [Chemical Department of Sassari University, Sassari (Italy)

    2007-05-15

    We propose an apparatus for teaching experimental thermodynamics in undergraduate introductory courses, using thermoelectric modules and a real-time data acquisition system. The device may be made at low cost, still providing an easy approach to the investigation of liquid-solid and liquid-vapour phase transitions and of metastable states (supercooling). The thermoelectric module (a technological evolution of the thermocouple) is by itself an interesting subject that offers a clear example of both thermo-electric (Seebeck effect) and electro-thermal (Peltier effect) energy transformation. We report here some cooling/heating measurements for several liquids and mixtures, including water, salt/water, ethanol/water and sodium acetate, showing how to evaluate the phenomena of freezing point depression and elevation, and how to evaluate the water latent heat.

  15. Using Peltier cells to study solid liquid vapour transitions and supercooling

    Science.gov (United States)

    Torzo, Giacomo; Soletta, Isabella; Branca, Mario

    2007-05-01

    We propose an apparatus for teaching experimental thermodynamics in undergraduate introductory courses, using thermoelectric modules and a real-time data acquisition system. The device may be made at low cost, still providing an easy approach to the investigation of liquid solid and liquid vapour phase transitions and of metastable states (supercooling). The thermoelectric module (a technological evolution of the thermocouple) is by itself an interesting subject that offers a clear example of both thermo-electric (Seebeck effect) and electro-thermal (Peltier effect) energy transformation. We report here some cooling/heating measurements for several liquids and mixtures, including water, salt/water, ethanol/water and sodium acetate, showing how to evaluate the phenomena of freezing point depression and elevation, and how to evaluate the water latent heat.

  16. A maximum-entropy approach to the adiabatic freezing of a supercooled liquid.

    Science.gov (United States)

    Prestipino, Santi

    2013-04-28

    I employ the van der Waals theory of Baus and co-workers to analyze the fast, adiabatic decay of a supercooled liquid in a closed vessel with which the solidification process usually starts. By imposing a further constraint on either the system volume or pressure, I use the maximum-entropy method to quantify the fraction of liquid that is transformed into solid as a function of undercooling and of the amount of a foreign gas that could possibly be also present in the test tube. Upon looking at the implications of thermal and mechanical insulation for the energy cost of forming a solid droplet within the liquid, I identify one situation where the onset of solidification inevitably occurs near the wall in contact with the bath.

  17. The glass crossover from mean-field Spin-Glasses to supercooled liquids

    Science.gov (United States)

    Rizzo, Tommaso

    2016-03-01

    Stochastic-Beta-Relaxation provides a characterisation of the glass crossover in discontinuous Spin-Glasses and supercoooled liquid. Notably it can be derived through a rigorous computation from a dynamical Landau theory. In this paper, I will discuss the precise meaning of this connection in a language that does not require familiarity with statistical field theory. I will discuss finite-size corrections in mean-field Spin-Glass models and loop corrections in finite-dimensional models that are both described by the dynamical Landau theory considered. Then I will argue that the same Landau theory can be associated to supercooled liquid described by Mode-Coupling Theory invoking a physical principle of time-scale invariance.

  18. Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography

    NARCIS (Netherlands)

    Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

    2006-01-01

    A gas chromatographic method using Kovats retention indices has been applied to determine the liquid vapour pressure (P-i), enthalpy of vaporization (Delta H-i) and difference in heat capacity between gas and liquid phase (Delta C-i) for a group of polycyclic aromatic hydrocarbons (PAHs). This group

  19. Measuring ice and liquid water content in moderately supercooled clouds with Cloudnet

    Science.gov (United States)

    Bühl, Johannes; Seifert, Patric; Myagkov, Alexander; Albert, Ansmann

    2016-04-01

    The interaction between ice nuclei and clouds is an important topic in weather and climate research. Recent laboratory experiments and field in-situ field campaigns present more and more detailed measurements of ice nucleating particles (INP) at temperatures close to 0°C. This brings moderately supercooled mixed-phase clouds into the focus of current cloud research. One current example is the European Union BACCHUS project. A major goal of BACCHUS is the analysis of the anthropogenic impact on ice nucleation. Within this project, we use the Leipzig Aerosol Cloud Remote Observations System (LACROS) and the Cloudnet framework in order to get quantitative insight into the formation of ice in mixed-phase layered clouds with cloud top temperature (CTT) from -40 to 0°C. Depolarization measurements from lidar and radar show a clear dependence between particle shape and the temperature under which the particles have been formed. The special focus of this work is on the CTT range from -10 to 0°C. An algorithm is presented to decide between ice and liquid water precipitation falling from the clouds showing that between 10% and 30% of all layered clouds show ice precipitation with CTT between -5 and 0°C. For these slightly supercooled clouds an average ice-water-content between 10e-7 and 10e-8 [kg per cubic meter] is found.

  20. Elastic properties of Pd40Cu30Ni10P20 bulk glass in supercooled liquid region

    DEFF Research Database (Denmark)

    Nishiyama, N.; Inoue, A.; Jiang, Jianzhong

    2001-01-01

    In situ ultrasonic measurements for the Pd40Cu30Ni10P20 bulk glass in three states: Glassy solid, supercooled liquid, and crystalline, have been performed. It is found that velocities of both longitudinal and transverse waves and elastic moduli (shear modulus, bulk modulus, Young's modulus, and L...

  1. Local structure of equilibrium and supercooled Ti-Zr-Ni liquids

    Energy Technology Data Exchange (ETDEWEB)

    Lee, G. W.; Gangopadhyay, A.; Hyers, R.; Rathz, T.; Rogers, J.; Robinson, D.; Goldman, A.; Kelton, K.

    2008-05-01

    Recently, we reported the results of experimental in situ high-energy x-ray diffraction studies of electrostatically levitated equilibrium and supercooled metallic elements and alloy liquids, showing evidence for icosahedral short-range ordering (ISRO). In this paper, these studies are extended to binary Ti-Zr and ternary Ti-Zr-Ni alloys. From a cluster-based analysis of the x-ray structure factors, it is concluded that ISRO in the binary alloys becomes progressively more dominant, and the coherence length of the order becomes longer, with the addition of Ni, especially near the concentration of 21 at. % Ni. The effect of chemical interactions among Ti/Zr-Ni and the atomic size on the stabilization of the ISRO is discussed.

  2. Electron Correlation Microscopy: A New Technique for Studying Local Atom Dynamics Applied to a Supercooled Liquid.

    Science.gov (United States)

    He, Li; Zhang, Pei; Besser, Matthew F; Kramer, Matthew Joseph; Voyles, Paul M

    2015-08-01

    Electron correlation microscopy (ECM) is a new technique that utilizes time-resolved coherent electron nanodiffraction to study dynamic atomic rearrangements in materials. It is the electron scattering equivalent of photon correlation spectroscopy with the added advantage of nanometer-scale spatial resolution. We have applied ECM to a Pd40Ni40P20 metallic glass, heated inside a scanning transmission electron microscope into a supercooled liquid to measure the structural relaxation time τ between the glass transition temperature T g and the crystallization temperature, T x . τ determined from the mean diffraction intensity autocorrelation function g 2(t) decreases with temperature following an Arrhenius relationship between T g and T g +25 K, and then increases as temperature approaches T x . The distribution of τ determined from the g 2(t) of single speckles is broad and changes significantly with temperature.

  3. Vibrating-Wire, Supercooled Liquid Water Content Sensor Calibration and Characterization Progress

    Science.gov (United States)

    King, Michael C.; Bognar, John A.; Guest, Daniel; Bunt, Fred

    2016-01-01

    NASA conducted a winter 2015 field campaign using weather balloons at the NASA Glenn Research Center to generate a validation database for the NASA Icing Remote Sensing System. The weather balloons carried a specialized, disposable, vibrating-wire sensor to determine supercooled liquid water content aloft. Significant progress has been made to calibrate and characterize these sensors. Calibration testing of the vibrating-wire sensors was carried out in a specially developed, low-speed, icing wind tunnel, and the results were analyzed. The sensor ice accretion behavior was also documented and analyzed. Finally, post-campaign evaluation of the balloon soundings revealed a gradual drift in the sensor data with increasing altitude. This behavior was analyzed and a method to correct for the drift in the data was developed.

  4. Correlation between supercooled liquid relaxation and glass poisson’s ratio

    DEFF Research Database (Denmark)

    Sun, Q.J.; Hu, L.N.; Zhou, C.

    2015-01-01

    We report on a correlation between the supercooled liquid (SL) relaxation and glass Poisson’s ratio (v) by comparing the activation energy ratio (r) of the α and the slow β relaxations and the v values for both metallic and nonmetallic glasses. Poisson’s ratio v generally increases with an increase...... in the ratio r and this relation can be described by the empirical function v = 0.5 − A ∗ exp(−B ∗ r), where A and B are constants. This correlation might imply that glass plasticity is associated with the competition between the α and the slow β relaxations in SLs. The underlying physics of this correlation...

  5. Dynamic heterogeneity in crossover spin facilitated model of supercooled liquid and fractional Stokes-Einstein relation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seo-Woo; Kim, Soree; Jung, YounJoon, E-mail: yjjung@snu.ac.kr [Department of Chemistry, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2015-06-28

    Kinetically constrained models have gained much interest as models that assign the origins of interesting dynamic properties of supercooled liquids to dynamical facilitation mechanisms that have been revealed in many experiments and numerical simulations. In this work, we investigate the dynamic heterogeneity in the fragile-to-strong liquid via Monte Carlo method using the model that linearly interpolates between the strong liquid-like behavior and the fragile liquid-like behavior by an asymmetry parameter b. When the asymmetry parameter is sufficiently small, smooth fragile-to-strong transition is observed both in the relaxation time and the diffusion constant. Using these physical quantities, we investigate fractional Stokes-Einstein relations observed in this model. When b is fixed, the system shows constant power law exponent under the temperature change, and the exponent has the value between that of the Frederickson-Andersen model and the East model. Furthermore, we investigate the dynamic length scale of our systems and also find the crossover relation between the relaxation time. We ascribe the competition between energetically favored symmetric relaxation mechanism and entropically favored asymmetric relaxation mechanism to the fragile-to-strong crossover behavior.

  6. Molecular dynamics of supercooled ionic liquids studied by light scattering and dielectric spectroscopy

    Science.gov (United States)

    Pabst, Florian; Gabriel, Jan; Weigl, Peter; Blochowicz, Thomas

    2017-09-01

    We investigate molecular dynamics of two supercooled room temperature ionic liquids (RTILs) above of their glass transition temperature by means of dynamic light scattering and broadband dielectric spectroscopy from nanoseconds up to ≈105s . We show that a direct comparison of the raw data of these two techniques allows us to identify the reorientation of ions in the dielectric data, giving experimental evidence to a very recently proposed model of Gainaru et al. [1], stating that the conductivity process in ionic liquids takes place through a reorientational step of ions escaping their cage formed by surrounding counterions. Within this approach we can also understand the apparent decoupling of time constants from dielectric spectroscopy and light scattering, often found in ionic liquids, in a very natural way. Furthermore, as a consequence of knowing the reorientational part of the dielectric spectrum, we are able to show that two more processes contribute to these spectra, which are due to electrode polarization effects. The relative position of all three contributions vary among the systems and may overshadow each other, thus complicating the data analysis and favor misinterpretations.

  7. Breaking through the Glass Ceiling: The Correlation Between the Self-Diffusivity in and Krypton Permeation through Deeply Supercooled Liquid Nanoscale Methanol Films

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R. Scott; Matthiesen, Jesper; Kay, Bruce D.

    2010-03-28

    Molecular beam techniques, temperature-programmed desorption (TPD), and reflection absorption infrared spectroscopy (RAIRS) are used to explore the relationship between krypton permeation through and the self-diffusivity of supercooled liquid methanol at temperatures near (100-115 K) the glass transition temperature, Tg (103 K). Layered films, consisting of CH3OH and CD3OH, are deposited ontop of a monolayer of Kr on a graphene covered Pt(111) substrate at 25 K. Concurrent Kr TPD and RAIRS spectra are acquired during the heating of the composite film to temperatures above Tg. The CO vibrational stretch is sensitive to the local molecular environment and is used to determine the supercooled liquid diffusivity from the intermixing of the isotopic layers. We find that the Kr permeation and the diffusivity of the supercooled liquid are directly and quantitatively correlated. These results validate the rare gas permeation technique as a tool for probing the diffusivity of supercooled liquids.

  8. Breaking through the glass ceiling: The correlation between the self-diffusivity in and krypton permeation through deeply supercooled liquid nanoscale methanol films

    Science.gov (United States)

    Smith, R. Scott; Matthiesen, Jesper; Kay, Bruce D.

    2010-03-01

    Molecular beam techniques, temperature-programmed desorption (TPD), and reflection absorption infrared spectroscopy (RAIRS) are used to explore the relationship between krypton permeation through and the self-diffusivity of supercooled liquid methanol at temperatures (100-115 K) near the glass transition temperature, Tg (103 K). Layered films, consisting of CH3OH and CD3OH, are deposited on top of a monolayer of Kr on a graphene covered Pt(111) substrate at 25 K. Concurrent Kr TPD and RAIRS spectra are acquired during the heating of the composite film to temperatures above Tg. The CO vibrational stretch is sensitive to the local molecular environment and is used to determine the supercooled liquid diffusivity from the intermixing of the isotopic layers. We find that the Kr permeation and the diffusivity of the supercooled liquid are directly and quantitatively correlated. These results validate the rare-gas permeation technique as a tool for probing the diffusivity of supercooled liquids.

  9. Detection of supercooled liquid water-topped mixed-phase clouds >from shortwave-infrared satellite observations

    Science.gov (United States)

    NOH, Y. J.; Miller, S. D.; Heidinger, A. K.

    2015-12-01

    Many studies have demonstrated the utility of multispectral information from satellite passive radiometers for detecting and retrieving the properties of cloud globally, which conventionally utilizes shortwave- and thermal-infrared bands. However, the satellite-derived cloud information comes mainly from cloud top or represents a vertically integrated property. This can produce a large bias in determining cloud phase characteristics, in particular for mixed-phase clouds which are often observed to have supercooled liquid water at cloud top but a predominantly ice phase residing below. The current satellite retrieval algorithms may report these clouds simply as supercooled liquid without any further information regarding the presence of a sub-cloud-top ice phase. More accurate characterization of these clouds is very important for climate models and aviation applications. In this study, we present a physical basis and preliminary results for the algorithm development of supercooled liquid-topped mixed-phase cloud detection using satellite radiometer observations. The detection algorithm is based on differential absorption properties between liquid and ice particles in the shortwave-infrared bands. Solar reflectance data in narrow bands at 1.6 μm and 2.25 μm are used to optically probe below clouds for distinction between supercooled liquid-topped clouds with and without an underlying mixed phase component. Varying solar/sensor geometry and cloud optical properties are also considered. The spectral band combination utilized for the algorithm is currently available on Suomi NPP Visible/Infrared Imaging Radiometer Suite (VIIRS), Himawari-8 Advanced Himawari Imager (AHI), and the future GOES-R Advance Baseline Imager (ABI). When tested on simulated cloud fields from WRF model and synthetic ABI data, favorable results were shown with reasonable threat scores (0.6-0.8) and false alarm rates (0.1-0.2). An ARM/NSA case study applied to VIIRS data also indicated promising

  10. Improvements of the experimental apparatus for measurement of the surface tension of supercooled liquids using horizontal capillary tube

    Directory of Open Access Journals (Sweden)

    Vinš Václav

    2016-01-01

    Full Text Available An experimental apparatus with a horizontal capillary tube for measurement of the surface tension of supercooled liquids, i.e. liquids in a metastable state below the equilibrium freezing point, was designed and tested in the previous study [V. Vinš et al., EPJ Web Conf. 92, 02108 (2015]. In this work, recent modifications of both the experimental setup and the measurement analysis are described. The main aim is to improve the accuracy and the reproducibility of measured surface tension and to achieve higher degrees of supercooling. Temperature probes measuring the temperature of cooling medium near the horizontal capillary tube were calibrated in the relevant temperature range from – 31 °C to + 45 °C. An additional pressure transducer was installed in the helium distribution setup at the position close to the capillary tube. The optical setup observing the liquid meniscus at the open end of the horizontal capillary tube together with the video analysis were thoroughly revised. The red laser illuminating the liquid meniscus, used at the original apparatus, was replaced by a fiber optic light source, which significantly improved the quality of the meniscus image. The modified apparatus was used for the measurement of surface tension of supercooled water at temperatures down to – 11 °C. The new data have a lower scatter compared to the previous horizontal measurements and show a good agreement with the other data obtained with a different measurement technique based on the modified capillary rise method.

  11. Understanding the nonlinear dynamics of driven particles in supercooled liquids in terms of an effective temperature

    Energy Technology Data Exchange (ETDEWEB)

    Schroer, Carsten F. E., E-mail: c.schroer@uni-muenster.de [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster (Germany); NRW Graduate School of Chemistry, Wilhelm-Klemm-Straße 10, 48149 Münster (Germany); Heuer, Andreas, E-mail: andheuer@uni-muenster.de [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster (Germany); Center of Nonlinear Science, Corresstraße 2, 48149 Münster (Germany); Center for Multiscale Theory and Computation, Corrensstraße 40, 48149 Münster (Germany)

    2015-12-14

    In active microrheology, the mechanical properties of a material are tested by adding probe particles which are pulled by an external force. In case of supercooled liquids, strong forcing leads to a thinning of the host material which becomes more pronounced as the system approaches the glass transition. In this work, we provide a quantitative theoretical description of this thinning behavior based on the properties of the Potential Energy Landscape (PEL) of a model glass-former. A key role plays the trap-like nature of the PEL. We find that the mechanical properties in the strongly driven system behave the same as in a quiescent system at an enhanced temperature, giving rise to a well-characterized effective temperature. Furthermore, this effective temperature turns out to be independent of the chosen observable and individually shows up in the thermodynamic and dynamic properties of the system. Based on this underlying theoretical understanding, we can estimate its dependence on temperature and force by the PEL-properties of the quiescent system. We furthermore critically discuss the relevance of effective temperatures obtained by scaling relations for the description of out-of-equilibrium situations.

  12. Hard rhenium–boron–cobalt amorphous alloys with a wide supercooled liquid region

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianfeng, E-mail: jfwang316@zzu.edu.cn [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Shijie; Wang, Liguo; Guan, Shaokang [School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Li, Ran; Zhang, Tao [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2015-10-01

    Novel Re–B–Co amorphous alloys with compositions of Re{sub 65−x}B{sub 35}Co{sub x} (at%, x=25, 30, 35, 40, 45, and 50) were fabricated by single-roller melt spinning. These alloys were found to exhibit a clear glass transition phenomenon. The width of supercooled liquid region (ΔT{sub x}) is in the range of 52–71 K. Such a large ΔT{sub x} allows us to produce amorphous alloy bulks by thermoplastic forming. The Vickers hardness is up to 19.10 GPa for the Re{sub 40}B{sub 35}Co{sub 25} alloy, which is close to that reported for some hard covalent crystals. Thus, the present alloys with a combination of large ΔT{sub x} and high hardness are expected to be used as a new type of structural materials. Furthermore, the relationships of hardness with glass transition temperature and Young's modulus were also discussed.

  13. Understanding the nonlinear dynamics of driven particles in supercooled liquids in terms of an effective temperature

    Science.gov (United States)

    Schroer, Carsten F. E.; Heuer, Andreas

    2015-12-01

    In active microrheology, the mechanical properties of a material are tested by adding probe particles which are pulled by an external force. In case of supercooled liquids, strong forcing leads to a thinning of the host material which becomes more pronounced as the system approaches the glass transition. In this work, we provide a quantitative theoretical description of this thinning behavior based on the properties of the Potential Energy Landscape (PEL) of a model glass-former. A key role plays the trap-like nature of the PEL. We find that the mechanical properties in the strongly driven system behave the same as in a quiescent system at an enhanced temperature, giving rise to a well-characterized effective temperature. Furthermore, this effective temperature turns out to be independent of the chosen observable and individually shows up in the thermodynamic and dynamic properties of the system. Based on this underlying theoretical understanding, we can estimate its dependence on temperature and force by the PEL-properties of the quiescent system. We furthermore critically discuss the relevance of effective temperatures obtained by scaling relations for the description of out-of-equilibrium situations.

  14. Liquid-liquid contact in vapor explosion. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Segev, A.

    1978-08-01

    The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture).

  15. Peculiar thermodynamics of the second critical point in supercooled water.

    Science.gov (United States)

    Bertrand, C E; Anisimov, M A

    2011-12-08

    On the basis of the principle of critical-point universality, we examine the peculiar thermodynamics of the liquid-liquid critical point in supercooled water. We show that the liquid-liquid criticality in water represents a special kind of critical behavior in fluids, intermediate between two limiting cases: the lattice gas, commonly used to model liquid-vapor transitions, and the lattice liquid, a weakly compressible liquid with an entropy-driven phase separation. While the ordering field in the lattice gas is associated with the chemical potential and the order parameter with the density, in the lattice liquid the ordering field is the temperature and the order parameter is the entropy. The behavior of supercooled water is much closer to lattice-liquid behavior than to lattice-gas behavior. Using new experimental data recently obtained by Mishima [J. Chem. Phys. 2010, 133, 144503], we have revised the parametric scaled equation of state, previously suggested by Fuentevilla and Anisimov [Phys. Rev. Lett. 2006, 97, 195702], and obtain a consistent description of the thermodynamic anomalies of supercooled water by adjusting linear backgrounds, one critical amplitude, and the critical pressure. We also show how the lattice-liquid description affects the finite-size scaling description of supercooled water in confined media.

  16. Heterogeneous nucleation from a supercooled ionic liquid on a carbon surface

    Science.gov (United States)

    He, Xiaoxia; Shen, Yan; Hung, Francisco R.; Santiso, Erik E.

    2016-12-01

    Classical molecular dynamics simulations were used to study the nucleation of the crystal phase of the ionic liquid [dmim+][Cl-] from its supercooled liquid phase, both in the bulk and in contact with a graphitic surface of D = 3 nm. By combining the string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)], with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589-2594 (2009)] and order parameters for molecular crystals [Santiso and Trout, J. Chem. Phys. 134, 064109 (2011)], we computed minimum free energy paths, the approximate size of the critical nucleus, the free energy barrier, and the rates involved in these nucleation processes. For homogeneous nucleation, the subcooled liquid phase has to overcome a free energy barrier of ˜85 kcal/mol to form a critical nucleus of size ˜3.6 nm, which then grows into the monoclinic crystal phase. This free energy barrier becomes about 42% smaller (˜49 kcal/mol) when the subcooled liquid phase is in contact with a graphitic disk, and the critical nucleus formed is about 17% smaller (˜3.0 nm) than the one observed for homogeneous nucleation. The crystal formed in the heterogeneous nucleation scenario has a structure that is similar to that of the bulk crystal, with the exception of the layers of ions next to the graphene surface, which have larger local density and the cations lie with their imidazolium rings parallel to the graphitic surface. The critical nucleus forms near the graphene surface separated only by these layers of ions. The heterogeneous nucleation rate (˜4.8 × 1011 cm-3 s-1) is about one order of magnitude faster than the homogeneous rate (˜6.6 × 1010 cm-3 s-1). The computed free energy barriers and nucleation rates are in reasonable agreement with experimental and simulation values obtained for the homogeneous and heterogeneous nucleation of other systems (ice, urea, Lennard-Jones spheres, and oxide glasses).

  17. Static and dynamic length scales in supercooled liquids: insights from molecular dynamics simulations of water and tri-propylene oxide.

    Science.gov (United States)

    Klameth, F; Henritzi, P; Vogel, M

    2014-04-14

    We perform molecular dynamics simulations to study static and dynamic length scales in molecular supercooled liquids, in particular, water. For a determination of these scales, we use equilibrium configurations and pin appropriate subsets of molecules so as to obtain random matrices, cylindrical pores, and slit confinements. Static length scales ξ(s) are determined by analyzing overlap correlation functions for various fractions of pinned molecules or distances to the confining walls. For water in all confinements and for propylene oxide trimers in random geometry, a linear increase of ξ(s) with inverse temperature is found. Dynamic length scales ξ(d) are determined by analogous analysis of fraction-dependent or position-resolved correlation times of structural relaxation. While ξ(d) continuously grows upon cooling in the cylindrical and slit confinements, we find no evidence for a temperature dependence in random matrices, implying that molecular dynamics in parsed volumes is qualitatively different from that in bulk liquids. Finally, we study possible connections between the growth of the static and dynamic length scales and the slowdown of the structural relaxation of the supercooled bulk liquids. For water, we observe a linear relation between ln τ(α) and ξ(s)²/T in the whole accessible range down to the critical temperature of mode-coupling theory, T(c). In the weakly supercooled regime, the same relation holds also for ξ(d), as obtained from cylindrical and slit confinements, but deviations from this behavior are observed near T(c). The results are discussed in connection with random first-order theory and experimental studies of liquid dynamics in nanoscopic confinements and binary mixtures.

  18. Volume of supercooled water under pressure and the liquid-liquid critical point.

    Science.gov (United States)

    Mishima, Osamu

    2010-10-14

    The volume of water (H(2)O) was obtained at about 200-275 K and 40-400 MPa by using emulsified water. The plot of volume against temperature showed slightly concave-downward curvature at pressures higher than ≈200 MPa. This is compatible with the liquid-liquid critical-point hypothesis, but hardly with the singularity-free scenario. When the critical point is assumed to exist at ≈50 MPa and ≈223 K, the experimental volume and the derived compressibility are qualitatively described by the modified Fuentevilla-Anisimov scaling equation.

  19. Elemental and cooperative diffusion in a liquid, supercooled liquid and glass resolved

    Science.gov (United States)

    Cassar, Daniel R.; Lancelotti, Ricardo F.; Nuernberg, Rafael; Nascimento, Marcio L. F.; Rodrigues, Alisson M.; Diz, Luiza T.; Zanotto, Edgar D.

    2017-07-01

    The diffusion mechanisms controlling viscous flow, structural relaxation, liquid-liquid phase separation, crystal nucleation, and crystal growth in multicomponent glass-forming liquids are of great interest and relevance in physics, chemistry, materials, and glass science. However, the diffusing entities that control each of these important dynamic processes are still unknown. The main objective of this work is to shed some light on this mystery, advancing the knowledge on this phenomenon. For that matter, we measured the crystal growth rates, the viscosity, and lead diffusivities in PbSiO3 liquid and glass in a wide temperature range. We compared our measured values with published data covering 16 orders of magnitude. We suggest that above a certain temperature range Td (1.2Tg-1.3Tg), crystal growth and viscous flow are controlled by the diffusion of silicon and lead. Below this temperature, crystal growth and viscous flow are more sluggish than the diffusion of silicon and lead. Therefore, Td marks the temperature where decoupling between the (measured) cationic diffusivity and the effective diffusivities calculated from viscosity and crystal growth rates occurs. We reasonably propose that the nature or size of the diffusional entities controlling viscous flow and crystal growth below Td is quite different; the slowest is the one controlling viscous flow, but both processes require cooperative movements of some larger structural units rather than jumps of only one or a few isolated atoms.

  20. Nature of the anomalies in the supercooled liquid state of the mW model of water

    CERN Document Server

    Holten, Vincent; Molinero, Valeria; Anisimov, Mikhail A

    2013-01-01

    The thermodynamic properties of the supercooled liquid state of the mW model of water show anomalous behavior. Like in real water, the heat capacity and compressibility sharply increase upon supercooling. One of the possible explanations of these anomalies, the existence of a second (liquid-liquid) critical point, is not supported by simulations for this particular model. In this work, we reproduce the anomalies of the mW model with two thermodynamic scenarios: one based on a non-ideal "mixture" with two different types of local order of the water molecules, and one based on weak crystallization theory. We show that both descriptions accurately reproduce the model's basic thermodynamic properties. However, the coupling constant required for fitting the power laws implied by weak crystallization theory is found not to be physically meaningful. For the two-state approach, the direct computation of the low-density fraction of molecules in the mW model is in agreement with the prediction of the phenomenological e...

  1. Predicting How Nanoconfinement Changes the Relaxation Time of a Supercooled Liquid

    DEFF Research Database (Denmark)

    Ingebrigtsen, Trond; Errington, Jeff; Truskett, Tom;

    2013-01-01

    asymmetric dumbbell-shaped molecules, which can be deeply supercooled without crystallizing. We find that the dimensionless structural relaxation times—spanning six decades as a function of temperature, density, and degree of confinement—collapse when plotted versus excess entropy. The data also collapse...

  2. The liquid to vapor phase transition in excited nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.

    2001-05-08

    For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid-vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197 Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

  3. The liquid to vapor phase transition in excited nuclei

    CERN Document Server

    Elliott, J B; Phair, L; Wozniak, G J; Lefort, T; Beaulieu, L; Kwiatkowski, K K; Hsi, W C; Pienkowski, L; Breuer, H; Korteling, R G; Laforest, R; Martin, E; Ramakrishnan, E; Rowland, D; Ruangma, A; Viola, V E; Winchester, E M; Yennello, S J

    2002-01-01

    For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid- vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

  4. Possible Evidence for a New Form of Liquid Buried in the Surface Tension of Supercooled Water

    Science.gov (United States)

    Rogers, T. Ryan; Leong, Kai-Yang; Wang, Feng

    2016-09-01

    Contrary to the historical data, several recent experiments indicate that the surface tension of supercooled water follows a smooth extrapolation of the IAPWS equation in the supercooled regime. It can be seen, however, that a small deviation from the IAPWS equation is present in the recent experimental measurements. It is shown with simulations using the WAIL water potential that the small deviation in the experimental data is consistent with the tail of an exponential growth in surface tension as temperature decreases. The emergence temperature, Te, of a substantial deviation from the IAPWS equation is shown to be 227 K for the WAIL water and 235 K for real water. Since the 227 K Te is close to the Widom line in WAIL water, we argue that real water at 235 K approaches a similar crossover line at one atmospheric pressure.

  5. Volumetric properties of magnesium silicate glasses and supercooled liquid at high pressure by X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Lesher, Charles E.; Wang, Yanbin; Gaudio, Sarah; Clark, Alisha; Nishiyama, Nori; Rivers, Mark; (UCD); (UC)

    2009-06-01

    The volumetric properties of silicate glasses and supercooled liquid are examined at high pressures and temperatures using X-ray computed tomography (CT) and absorption. The high pressure X-ray microtomography (HPXMT) system at the Advanced Photon Source, Argonne National Laboratory (GeoSoilEnvironCARS 13-BM-D beamline) consists of two opposing anvils compressed within an X-ray-transparent containment ring supported by thrust bearings and loaded using a 250-ton hydraulic press. This system permits the pressure cell to rotate under the load, while collecting radiographs through at least 180{sup o} of rotation. The 13-BM-D beamline permits convenient switching between monochromatic radiation required for radiography and polychromatic radiation for pressure determination by energy dispersive diffraction. We report initial results on several refractory magnesium silicate glasses synthesized by levitation laser heating. Volume changes during room temperature compression of Mg-silicate glasses with 33 mol% and 38 mol% SiO2 up to 11.5 GPa give an isothermal bulk moduli of 93--100 GPa for a K' of 1. These values are consistent with ultrasonic measurements of more silica-rich glasses. The volumetric properties of amorphous MgSiO{sub 3} at 2 GPa were examined during annealing up to 1000 C. We consider the consequences of heating through the glass transition and the implications for thermal expansivity of supercooled liquids at high pressure. Our results illustrate the capabilities of HPXMT for studies of refractory glasses and liquids at high pressure and offer strategies for future studies of liquid densities within the melting interval for magmas in planet interiors.

  6. An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

    Directory of Open Access Journals (Sweden)

    Vinš Václav

    2015-01-01

    Full Text Available New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

  7. Method And Apparatus For Atomizing And Vaporizing Liquid

    KAUST Repository

    Lal, Amit

    2014-09-18

    A method and apparatus for atomizing and vaporizing liquid is described. An apparatus having an ejector configured to eject one or more droplets of liquid may be inserted into a reservoir containing liquid. The ejector may have a vibrating device that vibrates the ejector and causes liquid to move from the reservoir up through the ejector and out through an orifice located on the top of the ejector. The one or more droplets of liquid ejected from the ejector may be heated and vaporized into the air.

  8. Excess liquid in heat-pipe vapor spaces

    Science.gov (United States)

    Eninger, J. E.; Edwards, D. K.

    1977-01-01

    A mathematical model is developed of excess liquid in heat pipes that is used to calculate the parameters governing the axial flow of liquid in fillets and puddles that form in vapor spaces. In an acceleration field, the hydrostatic pressure variation is taken into account, which results in noncircular meniscus shapes. The two specific vapor-space geometries considered are circular and the 'Dee-shape' that is formed by a slab wick in a circular tube. Also presented are theoretical and experimental results for the conditions under which liquid slugs form at the ends of the vapor spaces. These results also apply to the priming of arteries.

  9. Supercooled smectic nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Westesen, K; Drechsler, M

    2004-01-01

    The possibility of preparing nanoparticles in the supercooled thermotropic liquid crystalline state from cholesterol esters with saturated acyl chains as well as the incorporation of model drugs into the dispersions was investigated using cholesteryl myristate (CM) as a model cholesterol ester....

  10. Supercooled smectic nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Westesen, K; Drechsler, M

    2004-01-01

    The possibility of preparing nanoparticles in the supercooled thermotropic liquid crystalline state from cholesterol esters with saturated acyl chains as well as the incorporation of model drugs into the dispersions was investigated using cholesteryl myristate (CM) as a model cholesterol ester....

  11. Synchrotron X-ray studies of liquid-vapor interfaces

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1986-01-01

    The density profile ρ(z) across a liquid-vapor interface may be determined by the reflectivity R(θ) of X-rays at grazing angle incidence θ. The relation between R(θ) and ρ(z) is discussed, and experimental examples illustrating thermal roughness of simple liquids and smectic layering of liquid...

  12. Numerical simulation of superheated vapor bubble rising in stagnant liquid

    Science.gov (United States)

    Samkhaniani, N.; Ansari, M. R.

    2017-09-01

    In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

  13. Liquid-liquid transition in supercooled aqueous solution involving a low-temperature phase similar to low-density amorphous water

    CERN Document Server

    Woutersen, Sander; Zhao, Zuofeng; Angell, C Austen

    2016-01-01

    The striking anomalies in physical properties of supercooled water that were discovered in the 1960-70s, remain incompletely understood and so provide both a source of controversy amongst theoreticians, and a stimulus to experimentalists and simulators to find new ways of penetrating the "crystallization curtain" that effectively shields the problem from solution. Recently a new door on the problem was opened by showing that, in ideal solutions, made using ionic liquid solutes, water anomalies are not destroyed as earlier found for common salt and most molecular solutes, but instead are enhanced to the point of precipitating an apparently first order liquid-liquid transition. The evidence was a spike in apparent heat capacity during cooling that could be fully reversed during reheating before any sign of ice crystallization appeared. Here, we use decoupled-oscillator infrared spectroscopy to define the structural character of this phenomenon using similar down and upscan rates as in the calorimetric study. Th...

  14. Deformation behavior of Zr-based bulk metallic glass and composite in the supercooled liquid region

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A Zr-based bulk metallic glass (BMG) with a composition of (Zr75Cu25)78.5Ta4Ni10Al7.5 and a bulk metallic glass matrix composite (BMGC) with a composition of (Zr75Cu25)74.5Ta8Ni10Al7.5 have been prepared by copper-mold casting. The compres-sive deformation behavior of the BMG and BMGC was investigated in the super-cooled region at different temperatures and various strain rates ranging from 8×10-4s-1 to 8×10-2s-1. It was found that both the strain rate and test temperature signifi-cantly affect the deformation behavior of the two alloys. The deformation follows Newtonian flow at low strain rates but non-Newtonian flow at high strain rates. The deformation mechanism for the two kinds of alloys was discussed in terms of the transition state theory.

  15. Molecular dynamics investigation of dynamical heterogeneity and local structure in the supercooled liquid and glass states of Al

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.; Wang, C. Z.; Mandelev, M.; Ho, K. M.

    2008-05-13

    Molecular dynamics simulations are performed to study the structure and dynamical heterogeneity in the liquid and glass states of Al using a frequently employed embedded atom potential. While the pair correlation function of the glass and liquid states displays only minor differences, the icosahedral short-range order (ISRO) and the dynamics of the two states are very different. The ISRO is much stronger in the glass than in the liquid. It is also found that both the most mobile and the most immobile atoms in the glass state tend to form clusters, and the clusters formed by the immobile atoms are more compact. In order to investigate the local environment of each atom in the liquid and glass states, a local density is defined to characterize the local atomic packing. There is a strong correlation between the local packing density and the mobility of the atoms. These results indicate that dynamical heterogeneity in glasses is directly correlated to the local structure. We also analyze the diffusion mechanisms of atoms in the liquid and glass states. It is found that for the mobile atoms in the glass state, initially they are confined in the cages formed by their nearest neighbors and vibrating. On the time scale of {beta} relaxation, the mobile atoms try to break up the cage confinement and hop into new cages. In the supercooled liquid states, however, atoms continuously diffuse. Furthermore, it is found that on the time scale of {beta} relaxation, some of the mobile atoms in the glass state cooperatively hop, which is facilitated by the stringlike cluster structures. On the longer time scale, it is found that a certain fraction of atoms can simultaneously hop, although they are not nearest neighbors. Further analysis shows that these hopping atoms form big and more compact clusters than the characterized most mobile atoms. The cooperative rearrangement of these big compact clusters might facilitate the simultaneous hopping of atoms in the glass states on the long

  16. Non-equilibrium phenomena near vapor-liquid interfaces

    CERN Document Server

    Kryukov, Alexei; Puzina, Yulia

    2013-01-01

    This book presents information on the development of a non-equilibrium approach to the study of heat and mass transfer problems using vapor-liquid interfaces, and demonstrates its application to a broad range of problems. In the process, the following peculiarities become apparent: 1. At vapor condensation on the interface from gas-vapor mixture, non-condensable components can lock up the interface surface and condensation stops completely. 2. At the evolution of vapor film on the heater in superfluid helium (He-II), the boiling mass flux density from the vapor-liquid interface is effectively zero at the macroscopic scale. 3. In problems concerning the motion of He-II bridges inside capillaries filled by vapor, in the presence of axial heat flux the He-II bridge cannot move from the heater as would a traditional liquid, but in the opposite direction instead. Thus the heater attracts the superfluid helium bridge. 4. The shape of liquid-vapor interface at film boiling on the axis-symmetric heaters immersed in l...

  17. Workability of the supercooled liquid in the Zr{sub 65}Al{sub 10}Ni{sub 10}Cu{sub 15} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Y.; Shibata, T.; Inoue, A.; Masumoto, T. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research

    1997-12-19

    The workability of the supercooled liquid in metallic glass has been examined through the extrusion of a Zr{sub 6.5}Al{sub 10}Ni{sub 10}Cu{sub 15} at.% bulk glassy alloy with a wide supercooled liquid region. The metallic glass exhibited superplastic-like deformation behavior at high strain rates, resulting in an excellent workability. The working throughout a wide range of extrusion conditions was compatible with retaining the glass phase and the original strength. The extrusion maps and the expression between extrusion temperature, pressure and ram-speed have been established. Moreover, the features of working such as the Barus effect and the advantage of a small stepwise increase in strain rate have been revealed.

  18. Vapor-liquid equilibrium in electric field gradients.

    Science.gov (United States)

    Samin, Sela; Tsori, Yoav

    2011-01-13

    We investigate the vapor-liquid coexistence of polar and nonpolar fluids in the presence of a nonuniform electric field. We find that a large enough electric field can nucleate a gas bubble from the liquid phase or a liquid droplet from the vapor phase. The surface tension of the vapor-liquid interface is determined within squared-gradient theory. When the surface potential (charge) is controlled, the surface tension increases (decreases) compared to the zero-field interface. The effect of the electric field on the fluid phase diagram depends strongly on the constitutive relation for the dielectric constant. Finally, we show that gas bubbles can be nucleated far from the bounding surfaces.

  19. Ionic Vapor Composition in Pyridinium-Based Ionic Liquids.

    Science.gov (United States)

    Chaban, Vitaly V; Prezhdo, Oleg V

    2016-05-26

    Strong electrostatic interactions in ionic compounds make vaporization a complex process. The gas phase can contain a broad range of ionic clusters, and the cluster composition can differ greatly from that in the liquid phase. Room-temperature ionic liquids (RTILs) constitute a complicated case due to their ionic nature, asymmetric structure, and a huge versatility of ions and ionic clusters. This work reports vapor-liquid equilibria and vapor compositions of butylpyridinium (BPY) RTILs formed with hexafluorophosphate (PF6), trifluoromethanesulfonate (TF), and bis(trifluoromethanesulfonyl)imide (TFSI) anions. Unlike inorganic crystals, the pyridinium-based RTILs contain significant percentages of charged clusters in the vapor phase. Ion triplets and ion quadruplets each constitute up to 10% of the vapor phase composition. Triples prevail over quadruples in [BPY][PF6] due to the size difference of the cation and the anion. The percentage of charged ionic clusters in the gas phase is in inverse proportion to the mass of the anion. The largest identified vaporized ionic cluster comprises eight ions, with a formation probability below 1%. Higher temperature fosters formation of larger clusters due to an increase of the saturated vapor density.

  20. Liquid-vapor interface of a polydisperse fluid.

    Science.gov (United States)

    Buzzacchi, Matteo; Wilding, Nigel B

    2005-06-01

    We report a grand canonical Monte Carlo simulation study of the liquid-vapor interface of a model fluid exhibiting polydispersity in terms of the particle size sigma. The bulk density distribution, rho0(sigma), of the system is controlled by the imposed chemical potential distribution mu(sigma), the form of which is specified such that rho0(sigma) assumes a Schulz form with associated degree of polydispersity approximately = 14%. By introducing a smooth attractive wall, a planar liquid-vapor interface is formed for bulk state points within the region of liquid-vapor coexistence. Owing to fractionation, the pure liquid phase is enriched in large particles, with respect to the coexisting vapor. We investigate how the spatial variation of the density near the liquid-vapor interface affects the evolution of the local distribution of particle sizes between the limiting pure phase forms. We find [as previously predicted by density-functional theory, Bellier-Castella, Phys. Rev. E 65, 021503 (2002)] a segregation of smaller particles to the interface. The magnitude of this effect as a function of sigma is quantified via measurements of the relative adsorption. Additionally, we consider the utility of various estimators for the interfacial width and highlight the difficulty of isolating the intrinsic contribution of polydispersity to this width.

  1. Communication: Towards first principles theory of relaxation in supercooled liquids formulated in terms of cooperative motion.

    Science.gov (United States)

    Freed, Karl F

    2014-10-14

    A general theory of the long time, low temperature dynamics of glass-forming fluids remains elusive despite the almost 20 years since the famous pronouncement by the Nobel Laureate P. W. Anderson, "The deepest and most interesting unsolved problem in solid state theory is probably the theory of the nature of glass and the glass transition" [Science 267, 1615 (1995)]. While recent work indicates that Adam-Gibbs theory (AGT) provides a framework for computing the structural relaxation time of supercooled fluids and for analyzing the properties of the cooperatively rearranging dynamical strings observed in low temperature molecular dynamics simulations, the heuristic nature of AGT has impeded general acceptance due to the lack of a first principles derivation [G. Adam and J. H. Gibbs, J. Chem. Phys. 43, 139 (1965)]. This deficiency is rectified here by a statistical mechanical derivation of AGT that uses transition state theory and the assumption that the transition state is composed of elementary excitations of a string-like form. The strings are assumed to form in equilibrium with the mobile particles in the fluid. Hence, transition state theory requires the strings to be in mutual equilibrium and thus to have the size distribution of a self-assembling system, in accord with the simulations and analyses of Douglas and co-workers. The average relaxation rate is computed as a grand canonical ensemble average over all string sizes, and use of the previously determined relation between configurational entropy and the average cluster size in several model equilibrium self-associating systems produces the AGT expression in a manner enabling further extensions and more fundamental tests of the assumptions.

  2. Using Peltier Cells to Study Solid-Liquid-Vapour Transitions and Supercooling

    Science.gov (United States)

    Torzo, Giacomo; Soletta, Isabella; Branca, Mario

    2007-01-01

    We propose an apparatus for teaching experimental thermodynamics in undergraduate introductory courses, using thermoelectric modules and a real-time data acquisition system. The device may be made at low cost, still providing an easy approach to the investigation of liquid-solid and liquid-vapour phase transitions and of metastable states…

  3. Employment of vapor pressure data in the description of vapor-liquid equilibrium with direct method

    Energy Technology Data Exchange (ETDEWEB)

    Morbidelli, M.; Carra, S.

    1981-07-01

    A general procedure for inserting vapor-pressure data of pure components into equations of state provides a straightforward scheme for the extension of direct methods to the study of phase equilibria of polar mixtures and of solutions containing nonvolatile electrolytes. It makes the equation of state applicable to all compounds and to the shole temperature range and more accurate in the prediction of both multicomponent and pure vapor-liquid equilibria.

  4. Shock wave of vapor-liquid two-phase flow

    Institute of Scientific and Technical Information of China (English)

    Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

    2008-01-01

    The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

  5. Towards 3D prediction of supercooled liquid water for aircraft icing: Modifications of the microphysics in COSMO-EU

    Directory of Open Access Journals (Sweden)

    Felix Köhler

    2014-09-01

    Full Text Available Supercooled liquid water (SLW in the atmosphere is responsible for aircraft icing which can cause severe accidents. To date, the microphysics scheme in the model of the Deutscher Wetterdienst (DWD for the European scale (COSMO-EU; due to be replaced by ICON-EU in 2015 has been optimised to forecast precipitation on the ground but not the water phase in the atmosphere. As a consequence, prediction of SLW is rather poor, as was shown in a series of case studies by the Aeronautical Meteorology department at DWD. ADWICE – the tool used by the DWD to predict aircraft icing – therefore does not rely on COSMO model SLW output, but predicts SLW by itself using a simple parcel method. In an effort to improve ADWICE it has been found that this algorithm has its limits and that it should be replaced by SLW prediction from a 3D weather prediction model. To this end it is necessary to improve the SLW prediction in the COSMO model. In this paper we analyse the microphysics scheme of COSMO-EU with respect to SLW production and depletion and present modifications that greatly improve SLW prediction. As reference for two case studies we use radar-lidar-radiometer products from the Meteorological Observatory Lindenberg to verify the change in SLW prediction.

  6. Effect of total and pair configurational entropy in determining dynamics of supercooled liquids over a range of densities

    Science.gov (United States)

    Banerjee, Atreyee; Nandi, Manoj Kumar; Sastry, Srikanth; Bhattacharyya, Sarika Maitra

    2016-07-01

    In this paper, we present a study of supercooled liquids interacting with the Lennard Jones potential and the corresponding purely repulsive (Weeks-Chandler-Andersen) potential, over a range of densities and temperatures, in order to understand the origin of their different dynamics in spite of their structures being similar. Using the configurational entropy as the thermodynamic marker via the Adam Gibbs relation, we show that the difference in the dynamics of these two systems at low temperatures can be explained from thermodynamics. At higher densities both the thermodynamical and dynamical difference between these model systems decrease, which is quantitatively demonstrated in this paper by calculating different parameters. The study also reveals the origin of the difference in pair entropy despite the similarity in the structure. Although the maximum difference in structure is obtained in the partial radial distribution function of the B type of particles, the rdf of AA pairs and AB pairs gives rise to the differences in the entropy and dynamics. This work supports the observation made in an earlier study [A. Banerjee et al., Phys. Rev. Lett. 113, 225701 (2014)] and shows that they are generic in nature, independent of density.

  7. QSPR study of supercooled liquid vapour pressures of PBDEs by using molecular distance-edge vector index

    Directory of Open Access Journals (Sweden)

    Jiao Long

    2015-01-01

    Full Text Available The quantitative structure property relationship (QSPR for supercooled liquid vapour pressures (PL of PBDEs was investigated. Molecular distance-edge vector (MDEV index was used as the structural descriptor. The quantitative relationship between the MDEV index and lgPL was modeled by using multivariate linear regression (MLR and artificial neural network (ANN respectively. Leave-one-out cross validation and k-fold cross validation were carried out to assess the prediction ability of the developed models. For the MLR method, the prediction root mean square relative error (RMSRE of leave-one-out cross validation and k-fold cross validation is 9.95 and 9.05 respectively. For the ANN method, the prediction RMSRE of leave-one-out cross validation and k-fold cross validation is 8.75 and 8.31 respectively. It is demonstrated the established models are practicable for predicting the lgPL of PBDEs. The MDEV index is quantitatively related to the lgPL of PBDEs. MLR and L-ANN are practicable for modeling this relationship. Compared with MLR, ANN shows slightly higher prediction accuracy. Subsequently, an MLR model, which regression equation is lgPL = 0.2868 M11 - 0.8449 M12 - 0.0605, and an ANN model, which is a two inputs linear network, were developed. The two models can be used to predict the lgPL of each PBDE.

  8. Fluid metals the liquid-vapor transition of metals

    CERN Document Server

    Hensel, Friedrich

    2014-01-01

    This is a long-needed general introduction to the physics and chemistry of the liquid-vapor phase transition of metals. Physicists and physical chemists have made great strides understanding the basic principles involved, and engineers have discovered a wide variety of new uses for fluid metals. Yet there has been no book that brings together the latest ideas and findings in the field or that bridges the conceptual gap between the condensed-matter physics relevant to a dense metallic liquid and the molecular chemistry relevant to a dilute atomic vapor. Friedrich Hensel and William Warren seek

  9. Structural basis for supercooled liquid fragility established by synchrotron-radiation method and computer simulation

    Energy Technology Data Exchange (ETDEWEB)

    Louzguine-Luzgin, D. V.; Inoue, A. [WPI Advanced Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577 (Japan); Belosludov, R.; Kawazoe, Y. [Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577 (Japan); Yavari, A. R. [WPI Advanced Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577 (Japan); SIMAP-LTPCM, Institut National Polytechnique de Grenoble, St-Martin-d' Heres Campus, Grenoble, BP 75, 38402 (France); European Synchrotron Radiation Facility, 38042, Grenoble (France); Georgarakis, K. [WPI Advanced Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577 (Japan); SIMAP-LTPCM, Institut National Polytechnique de Grenoble, St-Martin-d' Heres Campus, Grenoble, BP 75, 38402 (France); Vaughan, G. [European Synchrotron Radiation Facility, 38042, Grenoble (France); Egami, T. [Joint Institute for Neutron Sciences, Department of Materials Science and Engineering and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); WPI Advanced Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577 (Japan)

    2011-08-15

    Metallic melts above the liquidus temperature exhibit nearly Arrhenius-type temperature dependence of viscosity. On cooling below the equilibrium liquidus temperature metallic melts exhibit a non-Arrhenius temperature dependence of viscosity characterized by liquid fragility phenomenon which origin is still not well understood. Structural changes and vitrification of the Pd{sub 42.5}Cu{sub 30}Ni{sub 7.5}P{sub 20} liquid alloy on cooling from above the equilibrium liquidus temperature are studied by synchrotron radiation X-ray diffraction and compared with the results of first-principles calculations. Subsequent analysis of the atomic and electronic structure of the alloy in liquid and glassy states reveals formation of chemical short-range order in the temperature range corresponding to such a non-Arrhenius behavior. The first-principles calculations were applied to confirm the experimental findings.

  10. Crystallization of Supercooled Liquid Elements Induced by Superclusters Containing Magic Atom Numbers

    Directory of Open Access Journals (Sweden)

    Robert F. Tournier

    2014-08-01

    Full Text Available A few experiments have detected icosahedral superclusters in undercooled liquids. These superclusters survive above the crystal melting temperature Tm because all their surface atoms have the same fusion heat as their core atoms, and are melted by liquid homogeneous and heterogeneous nucleation in their core, depending on superheating time and temperature. They act as heterogeneous growth nuclei of crystallized phase at a temperature Tc of the undercooled melt. They contribute to the critical barrier reduction, which becomes smaller than that of crystals containing the same atom number n. After strong superheating, the undercooling rate is still limited because the nucleation of 13-atom superclusters always reduces this barrier, and increases Tc above a homogeneous nucleation temperature equal to Tm/3 in liquid elements. After weak superheating, the most stable superclusters containing n = 13, 55, 147, 309 and 561 atoms survive or melt and determine Tc during undercooling, depending on n and sample volume. The experimental nucleation temperatures Tc of 32 liquid elements and the supercluster melting temperatures are predicted with sample volumes varying by 18 orders of magnitude. The classical Gibbs free energy change is used, adding an enthalpy saving related to the Laplace pressure change associated with supercluster formation, which is quantified for n = 13 and 55.

  11. A Kinetic Model for Vapor-liquid Flows

    Science.gov (United States)

    2005-07-13

    A Kinetic Model for Vapor-liquid Flows Aldo Frezzotti, Livio Gibelli and Silvia Lorenzani Dipartimento di Matematica del Politecnico di Milano Piazza...ES) Dipartimento di Matematica del Politecnico di Milano Piazza Leonardo da Vinci 32 - 20133 Milano - Italy 8. PERFORMING ORGANIZATION REPORT NUMBER

  12. A "User-Friendly" Program for Vapor-Liquid Equilibrium.

    Science.gov (United States)

    Da Silva, Francisco A.; And Others

    1991-01-01

    Described is a computer software package suitable for teaching and research in the area of multicomponent vapor-liquid equilibrium. This program, which has a complete database, can accomplish phase-equilibrium calculations using various models and graph the results. (KR)

  13. Student Understanding of Liquid-Vapor Phase Equilibrium

    Science.gov (United States)

    Boudreaux, Andrew; Campbell, Craig

    2012-01-01

    Student understanding of the equilibrium coexistence of a liquid and its vapor was the subject of an extended investigation. Written assessment questions were administered to undergraduates enrolled in introductory physics and chemistry courses. Responses have been analyzed to document conceptual and reasoning difficulties in sufficient detail to…

  14. Metal-organic frameworks as host materials of confined supercooled liquids.

    Science.gov (United States)

    Fischer, J K H; Sippel, P; Denysenko, D; Lunkenheimer, P; Volkmer, D; Loidl, A

    2015-10-21

    In this work, we examine the use of metal-organic framework (MOF) systems as host materials for the investigation of glassy dynamics in confined geometry. We investigate the confinement of the molecular glass former glycerol in three MFU-type MOFs with different pore sizes (MFU stands for "Metal-Organic Framework Ulm-University") and study the dynamics of the confined liquid via dielectric spectroscopy. In accord with previous reports on confined glass formers, we find different degrees of deviations from bulk behavior depending on pore size, demonstrating that MOFs are well-suited host systems for confinement investigations.

  15. Thermodynamic scaling of molecular dynamics in supercooled liquid state of pharmaceuticals: Itraconazole and ketoconazole.

    Science.gov (United States)

    Tarnacka, M; Madejczyk, O; Adrjanowicz, K; Pionteck, J; Kaminska, E; Kamiński, K; Paluch, M

    2015-06-14

    Pressure-Volume-Temperature (PVT) measurements and broadband dielectric spectroscopy were carried out to investigate molecular dynamics and to test the validity of thermodynamic scaling of two homologous compounds of pharmaceutical activity: itraconazole and ketoconazole in the wide range of thermodynamic conditions. The pressure coefficients of the glass transition temperature (dT(g)/dp) for itraconazole and ketoconazole were determined to be equal to 183 and 228 K/GPa, respectively. However, for itraconazole, the additional transition to the nematic phase was observed and characterized by the pressure coefficient dT(n)/dp = 258 K/GPa. From PVT and dielectric data, we obtained that the liquid-nematic phase transition is governed by the relaxation time since it occurred at constant τ(α) = 10(-5) s. Furthermore, we plotted the obtained relaxation times as a function of T(-1)v(-γ), which has revealed that the validity of thermodynamic scaling with the γ exponent equals to 3.69 ± 0.04 and 3.64 ± 0.03 for itraconazole and ketoconazole, respectively. Further analysis of the scaling parameter in itraconazole revealed that it unexpectedly decreases with increasing relaxation time, which resulted in dramatic change of the shape of the thermodynamic scaling master curve. While in the case of ketoconazole, it remained the same within entire range of data (within experimental uncertainty). We suppose that in case of itraconazole, this peculiar behavior is related to the liquid crystals' properties of itraconazole molecule.

  16. Modeling of vapor-liquid-liquid equilibria in binary mixtures

    NARCIS (Netherlands)

    Tzabar, Nir; ter Brake, Hermanus J.M.

    2016-01-01

    Vapor compression and Joule–Thomson (JT) cycles provide cooling power at the boiling temperatures of the refrigerants. Maintaining a fixed pressure in the evaporator allows for a stable cooling temperature at the boiling point of a pure refrigerant. In these coolers enhanced cooling power can be ach

  17. Thermodynamic geometry of supercooled water

    Science.gov (United States)

    May, Helge-Otmar; Mausbach, Peter; Ruppeiner, George

    2015-03-01

    The thermodynamic curvature scalar R is evaluated for supercooled water with a two-state equation of state correlated with the most recent available experimental data. This model assumes a liquid-liquid critical point. Our investigation extends the understanding of the thermodynamic behavior of R considerably. We show that R diverges to -∞ when approaching the assumed liquid-liquid critical point. This limit is consistent with all of the fluid critical point models known so far. In addition, we demonstrate a sign change of R along the liquid-liquid line from negative near the critical point to positive on moving away from the critical point in the low density "ice-like" liquid phase. We also trace out the Widom line in phase space. In addition, we investigate increasing correlation length in supercooled water and compare our results with recent published small angle x-ray scattering measurements.

  18. Thermodynamic scaling of molecular dynamics in supercooled liquid state of pharmaceuticals: Itraconazole and ketoconazole

    Energy Technology Data Exchange (ETDEWEB)

    Tarnacka, M., E-mail: mtarnacka@us.edu.pl; Madejczyk, O.; Kamiński, K.; Paluch, M. [Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center of Education and Interdisciplinary Research, University of Silesia, ul. 75 Pulku Piechoty 1A, 41-500 Chorzow (Poland); Adrjanowicz, K. [NanoBioMedical Centre, ul. Umultowska 85, 61-614 Poznan (Poland); Pionteck, J. [Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, D-01069 Dresden (Germany); Kaminska, E. [Department of Pharmacognosy and Phytochemistry, School of Pharmacy and Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, ul. Jagiellonska 4, 41-200 Sosnowiec (Poland)

    2015-06-14

    Pressure-Volume-Temperature (PVT) measurements and broadband dielectric spectroscopy were carried out to investigate molecular dynamics and to test the validity of thermodynamic scaling of two homologous compounds of pharmaceutical activity: itraconazole and ketoconazole in the wide range of thermodynamic conditions. The pressure coefficients of the glass transition temperature (dT{sub g}/dp) for itraconazole and ketoconazole were determined to be equal to 183 and 228 K/GPa, respectively. However, for itraconazole, the additional transition to the nematic phase was observed and characterized by the pressure coefficient dT{sub n}/dp = 258 K/GPa. From PVT and dielectric data, we obtained that the liquid-nematic phase transition is governed by the relaxation time since it occurred at constant τ {sub α} = 10{sup −5} s. Furthermore, we plotted the obtained relaxation times as a function of T{sup −1}v{sup −γ}, which has revealed that the validity of thermodynamic scaling with the γ exponent equals to 3.69 ± 0.04 and 3.64 ± 0.03 for itraconazole and ketoconazole, respectively. Further analysis of the scaling parameter in itraconazole revealed that it unexpectedly decreases with increasing relaxation time, which resulted in dramatic change of the shape of the thermodynamic scaling master curve. While in the case of ketoconazole, it remained the same within entire range of data (within experimental uncertainty). We suppose that in case of itraconazole, this peculiar behavior is related to the liquid crystals’ properties of itraconazole molecule.

  19. Supercooled Liquid Water Content Instrument Analysis and Winter 2014 Data with Comparisons to the NASA Icing Remote Sensing System and Pilot Reports

    Science.gov (United States)

    King, Michael C.

    2016-01-01

    The National Aeronautics and Space Administration (NASA) has developed a system for remotely detecting the hazardous conditions leading to aircraft icing in flight, the NASA Icing Remote Sensing System (NIRSS). Newly developed, weather balloon-borne instruments have been used to obtain in-situ measurements of supercooled liquid water during March 2014 to validate the algorithms used in the NIRSS. A mathematical model and a processing method were developed to analyze the data obtained from the weather balloon soundings. The data from soundings obtained in March 2014 were analyzed and compared to the output from the NIRSS and pilot reports.

  20. A highly modular beamline electrostatic levitation facility, optimized for in situ high-energy x-ray scattering studies of equilibrium and supercooled liquids.

    Science.gov (United States)

    Mauro, N A; Kelton, K F

    2011-03-01

    High-energy x-ray diffraction studies of metallic liquids provide valuable information about structural evolution on the atomic length scale, leading to insights into the origin of the nucleation barrier and the processes of supercooling and glass formation. The containerless processing of the beamline electrostatic levitation (BESL) facility allows coordinated thermophysical and structural studies of equilibrium and supercooled liquids to be made in a contamination-free, high-vacuum (∼10(-8) Torr) environment. To date, the incorporation of electrostatic levitation facilities into synchrotron beamlines has been difficult due to the large footprint of the apparatus and the difficulties associated with its transportation and implementation. Here, we describe a modular levitation facility that is optimized for diffraction studies of high-temperature liquids at high-energy synchrotron beamlines. The modular approach used in the apparatus design allows it to be easily transported and quickly setup. Unlike most previous electrostatic levitation facilities, BESL can be operated by a single user instead of a user team.

  1. Liquid-Vapor Equilibrium of Multicomponent Cryogenic Systems

    Science.gov (United States)

    Thompson, W. Reid; Calado, Jorge C. G.; Zollweg, John A.

    1990-01-01

    Liquid-vapor and solid-vapor equilibria at low to moderate pressures and low temperatures are important in many solar system environments, including the surface and clouds of Titan, the clouds of Uranus and Neptune, and the surfaces of Mars and Triton. The familiar cases of ideal behavior are limiting cases of a general thermodynamic representation for the vapor pressure of each component in a homogeneous multicomponent system. The fundamental connections of laboratory measurements to thermodynamic models are through the Gibbs-Duhem relation and the Gibbs-Helmholtz relation. Using laboratory measurements of the total pressure, temperature, and compositions of the liquid and vapor phases at equilibrium, the values of these parameters can be determined. The resulting model for vapor-liquid equilibrium can then conveniently and accurately be used to calculate pressures, compositions, condensation altitudes, and their dependencies on changing climatic conditions. A specific system being investigated is CH4-C2H6-N2, at conditions relevant to Titan's surface and atmosphere. Discussed are: the modeling of existing data on CH4-N2, with applications to the composition of Titan's condensate clouds; some new measurements on the CH4-C2H6 binary, using a high-precision static/volumetric system, and on the C2H6-N2 binary, using the volumetric system and a sensitive cryogenic flow calorimeter; and describe a new cryogenic phase-equilibrium vessel with which we are beginning a detailed, systematic study of the three constituent binaries and the ternary CH4-C2H6-N2 system at temperatures ranging from 80 to 105 K and pressures from 0.1 to 7 bar.

  2. FFT-LB Modeling of Thermal Liquid-Vapor System

    Institute of Scientific and Technical Information of China (English)

    甘延标; 许爱国; 张广财; 李英骏

    2012-01-01

    We present an improved lattice Boltzmann(LB) model for thermal liquid-vapor system.In the new model,the Windowed Fast Fourier Transform(WFFT) and its inverse are used to calculate both the convection term and the external force term of the LB equation.By adopting the WFFT scheme,Gibbs oscillations can be damped effectively in unsmooth regions while high resolution feature of the spectral method can be retained in smooth regions.As a result,spatial discretization errors are dramatically decreased,conservation of the total energy is much better preserved,and the spurious velocities near the liquid-vapor interface are significantly reduced.The high resolution,together with the low complexity of the WFFT approach,endows the proposed method with considerable potential for studying a wide class of problems in the field of multiphase flows.

  3. Qualitative Analysis of Liquid Hydrocarbon Mixtures by Absorption Spectra of Their Vapors

    Science.gov (United States)

    Vesnin, V. L.

    2016-11-01

    Absorption spectra of saturated vapors of hydrocarbons and their mixtures were studied near their first overtones. Absorption spectra of hydrocarbons in the liquid and vapor states were compared. The ability to analyze qualitatively the compositions of liquid hydrocarbon mixtures using absorption spectra of their vapors was demonstrated. Indirect evidence suggested that the nonlinear absorption as a function of concentration that was seen in liquid hydrocarbon mixtures was negligible in their vapors.

  4. Super-cooled liquid water topped sub-arctic clouds and precipitation - investigation based on combination of ground-based in-situ and remote-sensing observations

    Science.gov (United States)

    Hirsikko, Anne; Brus, David; O'Connor, Ewan J.; Filioglou, Maria; Komppula, Mika; Romakkaniemi, Sami

    2017-04-01

    In the high and mid latitudes super-cooled liquid water layers are frequently observed on top of clouds. These layers are difficult to forecast with numerical weather prediction models, even though, they have strong influence on atmospheric radiative properties, cloud microphysical properties, and subsequently, precipitation. This work investigates properties of super-cooled liquid water layer topped sub-arctic clouds and precipitation observed with ground-based in-situ (cloud probes) and remote-sensing (a cloud radar, Doppler and multi-wavelength lidars) instrumentation during two-month long Pallas Cloud Experiment (PaCE 2015) in autumn 2015. Analysis is based on standard Cloudnet scheme supplemented with new retrieval products of the specific clouds and their properties. Combination of two scales of observation provides new information on properties of clouds and precipitation in the sub-arctic Pallas region. Current status of results will be presented during the conference. The authors acknowledge financial support by the Academy of Finland (Centre of Excellence Programme, grant no 272041; and ICINA project, grant no 285068), the ACTRIS2 - European Union's Horizon 2020 research and innovation programme under grant agreement No 654109, the KONE foundation, and the EU FP7 project BACCHUS (grant no 603445).

  5. Non-contact property measurements of liquid and supercooled ceramics with a hybrid electrostatic-aerodynamic levitation furnace

    OpenAIRE

    Ishikawa, Takehiko; Yoda, Shinichi; Paradis, Paul-Francois; 石川 毅彦; 依田 真一

    2005-01-01

    The use of an hybrid pressurized electrostatic-aerodynamic levitation furnace and procedures developed by the Japan Aerospace Exploration Agency overcame the contamination problems associated with the processing of ceramics under extreme temperature conditions. This made possible property measurements over wide temperature ranges that cover the superheated as well as the supercooled states. In this study, samples of various ceramics were levitated and their densities were found as a function ...

  6. Molecular dynamics of the water liquid-vapor interface

    Science.gov (United States)

    Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

    1987-01-01

    The results of molecular dynamics calculations on the equilibrium interface between liquid water and its vapor at 325 K are presented. For the TIP4P model of water intermolecular pair potentials, the average surface dipole density points from the vapor to the liquid. The most common orientations of water molecules have the C2 nu molecular axis roughly parallel to the interface. The distributions are quite broad and therefore compatible with the intermolecular correlations characteristic of bulk liquid water. All near-neighbor pairs in the outermost interfacial layers are hydrogen bonded according to the common definition adopted here. The orientational preferences of water molecules near a free surface differ from those near rigidly planar walls which can be interpreted in terms of patterns found in hexagonal ice 1. The mean electric field in the interfacial region is parallel to the mean polarization which indicates that attention cannot be limited to dipolar charge distributions in macroscopic descriptions of the electrical properties of this interface. The value of the surface tension obtained is 132 +/- 46 dyn/cm, significantly different from the value for experimental water of 68 dyn/cm at 325 K.

  7. Liquid-Vapor Interface Configurations Investigated in Low Gravity

    Science.gov (United States)

    Concus, Paul; Finn, Robert; Weislogel, Mark M.

    1998-01-01

    The Interface Configuration Experiment (ICE) is part of a multifaceted study that is exploring the often striking behavior of liquid-vapor interfaces in low-gravity environments. Although the experiment was posed largely as a test of current mathematical theory, applications of the results should be manifold. In space almost every fluid system is affected, if not dominated, by capillarity (the effects of surface tension). As a result, knowledge of fluid interface behavior, in particular an equilibrium interface shape from which any analysis must begin, is fundamental--from the control of liquid fuels and oxygen in storage tanks to the design and development of inspace thermal systems, such as heat pipes and capillary pumped loops. ICE has increased, and should continue to increase, such knowledge as it probes the specific peculiarities of current theory upon which our present understanding rests. Several versions of ICE have been conducted in the drop towers at the NASA Lewis Research Center, on the space shuttles during the first and second United States Microgravity Laboratory missions (USML-1 and USML-2), and most recently aboard the Russian Mir space station. These studies focused on interfacial problems concerning the existence, uniqueness, configuration, stability, and flow characteristics of liquid-vapor interfaces. Results to date have clearly demonstrated the value of the present theory and the extent to which it can predict the behavior of capillary systems.

  8. Molecular dynamics of the water liquid-vapor interface

    Science.gov (United States)

    Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

    1987-01-01

    The results of molecular dynamics calculations on the equilibrium interface between liquid water and its vapor at 325 K are presented. For the TIP4P model of water intermolecular pair potentials, the average surface dipole density points from the vapor to the liquid. The most common orientations of water molecules have the C2 nu molecular axis roughly parallel to the interface. The distributions are quite broad and therefore compatible with the intermolecular correlations characteristic of bulk liquid water. All near-neighbor pairs in the outermost interfacial layers are hydrogen bonded according to the common definition adopted here. The orientational preferences of water molecules near a free surface differ from those near rigidly planar walls which can be interpreted in terms of patterns found in hexagonal ice 1. The mean electric field in the interfacial region is parallel to the mean polarization which indicates that attention cannot be limited to dipolar charge distributions in macroscopic descriptions of the electrical properties of this interface. The value of the surface tension obtained is 132 +/- 46 dyn/cm, significantly different from the value for experimental water of 68 dyn/cm at 325 K.

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

    Science.gov (United States)

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

    2005-11-01

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

  10. Molecular dynamics simulation of liquid-vapor surface tension

    Institute of Scientific and Technical Information of China (English)

    王德; ZENG; Danling; 等

    2002-01-01

    A molecular dynamics simulation model is established based on the well-known Lennard-Jones 12-6 potential function to determine the surface tension of a Lennard-Jones liquid-vapor interface.The simulation is carried out with argon as the working fluid of a given molecular number at different temperature and different truncated radius.It is found that the surface tension of a Lennard-Jones fluid is likely to be bigger for a bigger truncated radius,and tends to be constant after the truncated radius increased to a certain value.It is also found that the surface tension becomes smaller as the temperature increases.

  11. Flow Rate of He Ⅱ Liquid-Vapor Phase Separator

    Institute of Scientific and Technical Information of China (English)

    Xingen YU; Qing LI; Qiang LI; Zhengyu LI

    2005-01-01

    Experimental results are presented for superfluld (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. The temperature was measured from 1.5K to 1.9K. Two flow regions were observed in small and large pressure and temperature differences regions respectively. The experimental data are compared with theoretical predictions.The performance and applicability of the basic theory are discussed. Hysteresis of the flow rate is also observed and discussed.

  12. Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas-Liquid Interface Temperature.

    Science.gov (United States)

    Mohammadi, Morteza; Tembely, Moussa; Dolatabadi, Ali

    2017-02-28

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass-spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the resultant shear force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet contact time (e.g., 35% at a droplet Weber number of up to 140) was justified by the presence of a formed thin air layer underneath the impacting drop on the superhydrophobic surface (i.e., full slip condition). Finally, the droplet wetting model was also further developed to account for low temperature through the incorporation of classical nucleation theory. Homogeneous ice nucleation was integrated into the model through the concept of the reduction of the supercooled water drop surface tension as a function of the gas-liquid interface temperature, which was directly correlated with the Nusselt number of incoming air flow. It was shown that the experimental results was qualitatively predicted by the proposed model under all supercooling conditions (i.e., from -10 to -30 °C).

  13. Calculation of liquid-vapor and liquid-liquid equilibrium in multicomponent systems using correlations of equilibrium data

    OpenAIRE

    Reyes Labarta, Juan Antonio; Olaya López, María del Mar; Gómez Siurana, Amparo; Marcilla Gomis, Antonio

    1999-01-01

    Póster presentado en el congreso EQUIFASE 99 (Vigo, del 20 al 24 de Junio de 1999). Resumen publicado en el libro de actas del Congreso An algebraic correlation method to calculate equilibrium data for ternary vapor-liquid equilibrium and quaternary liquid-liquid equilibrium has been proposed. The proposed method allows the calculation of the conjugated phase in equilibrium with a given phase, and the calculation of the two phases in equilibrium from the composition of a heterogeneous glob...

  14. Two-structure thermodynamics for the TIP4P/2005 model of water covering supercooled and deeply stretched regions

    Science.gov (United States)

    Biddle, John W.; Singh, Rakesh S.; Sparano, Evan M.; Ricci, Francesco; González, Miguel A.; Valeriani, Chantal; Abascal, José L. F.; Debenedetti, Pablo G.; Anisimov, Mikhail A.; Caupin, Frédéric

    2017-01-01

    One of the most promising frameworks for understanding the anomalies of cold and supercooled water postulates the existence of two competing, interconvertible local structures. If the non-ideality in the Gibbs energy of mixing overcomes the ideal entropy of mixing of these two structures, a liquid-liquid phase transition, terminated at a liquid-liquid critical point, is predicted. Various versions of the "two-structure equation of state" (TSEOS) based on this concept have shown remarkable agreement with both experimental data for metastable, deeply supercooled water and simulations of molecular water models. However, existing TSEOSs were not designed to describe the negative pressure region and do not account for the stability limit of the liquid state with respect to the vapor. While experimental data on supercooled water at negative pressures may shed additional light on the source of the anomalies of water, such data are very limited. To fill this gap, we have analyzed simulation results for TIP4P/2005, one of the most accurate classical water models available. We have used recently published simulation data, and performed additional simulations, over a broad range of positive and negative pressures, from ambient temperature to deeply supercooled conditions. We show that, by explicitly incorporating the liquid-vapor spinodal into a TSEOS, we are able to match the simulation data for TIP4P/2005 with remarkable accuracy. In particular, this equation of state quantitatively reproduces the lines of extrema in density, isothermal compressibility, and isobaric heat capacity. Contrary to an explanation of the thermodynamic anomalies of water based on a "retracing spinodal," the liquid-vapor spinodal in the present TSEOS continues monotonically to lower pressures upon cooling, influencing but not giving rise to density extrema and other thermodynamic anomalies.

  15. Mixed quantum/classical approach to OH-stretch inelastic incoherent neutron scattering spectroscopy for ambient and supercooled liquid water and ice Ih

    Energy Technology Data Exchange (ETDEWEB)

    Shi, L.; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2015-07-07

    OH-stretch inelastic incoherent neutron scattering (IINS) has been measured to determine the vibrational density of states (VDOS) in the OH-stretch region for liquid water, supercooled water, and ice Ih, providing complementary information to IR and Raman spectroscopies about hydrogen bonding in these phases. In this work, we extend the combined electronic-structure/molecular-dynamics (ES/MD) method, originally developed by Skinner and co-workers to simulate OH-stretch IR and Raman spectra, to the calculation of IINS spectra with small k values. The agreement between theory and experiment in the limit k → 0 is reasonable, further validating the reliability of the ES/MD method in simulating OH-stretch spectroscopy in condensed phases. The connections and differences between IINS and IR spectra are analyzed to illustrate the advantages of IINS over IR in estimating the OH-stretch VDOS.

  16. Numerical Simulation of Vapor Bubble Growth and Heat Transfer in a Thin Liquid Film

    Institute of Scientific and Technical Information of China (English)

    TAO Yu-Jia; HUAI Xiu-Lan; LI Zhi-Gang

    2009-01-01

    A mathematical model is developed to investigate the dynamics of vapor bubble growth in a thin liquid film,movement of the interface between two fluids and the surface heat transfer characteristics. The model takes into account the effects of phase change between the vapor and liquid, gravity, surface tension and viscosity. The details of the multiphase flow and heat transfer are discussed for two cases: (1) when a water micro-droplet impacts a thin liquid fihn with a vapor bubble growing and (2) when the vapor bubble grows and merges with the vapor layer above the liquid film without the droplet impacting. The development trend of the interface between the vapor and liquid is coincident qualitatively with the available literature, mostly at the first stage. We also provide an important method to better understand the mechanism of nucleate spray cooling.

  17. Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface

    Science.gov (United States)

    Stewart, Mark E. M.

    2017-01-01

    This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

  18. Vapor condensation onto a non-volatile liquid drop

    Energy Technology Data Exchange (ETDEWEB)

    Inci, Levent; Bowles, Richard K., E-mail: richard.bowles@usask.ca [Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9 (Canada)

    2013-12-07

    Molecular dynamics simulations of miscible and partially miscible binary Lennard–Jones mixtures are used to study the dynamics and thermodynamics of vapor condensation onto a non-volatile liquid drop in the canonical ensemble. When the system volume is large, the driving force for condensation is low and only a submonolayer of the solvent is adsorbed onto the liquid drop. A small degree of mixing of the solvent phase into the core of the particles occurs for the miscible system. At smaller volumes, complete film formation is observed and the dynamics of film growth are dominated by cluster-cluster coalescence. Mixing into the core of the droplet is also observed for partially miscible systems below an onset volume suggesting the presence of a solubility transition. We also develop a non-volatile liquid drop model, based on the capillarity approximations, that exhibits a solubility transition between small and large drops for partially miscible mixtures and has a hysteresis loop similar to the one observed in the deliquescence of small soluble salt particles. The properties of the model are compared to our simulation results and the model is used to study the formulation of classical nucleation theory for systems with low free energy barriers.

  19. Tunable wavelength soft photoionization of ionic liquid vapors

    Energy Technology Data Exchange (ETDEWEB)

    Strasser, Daniel; Goulay, Fabien; Belau, Leonid; Kostko, Oleg; Koh, Christine; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Ahmed, Musahid; Leone, Stephen R.

    2009-11-11

    Combined data of photoelectron spectra and photoionization efficiency curves in the near threshold ionization region of isolated ion-pairs from [emim][Tf2N], [emim][Pf2N]and [dmpim][Tf2N]ionic liquid vapors reveal small shifts in the ionization energies of ion-pair systems due to cation and anion substitutions. Shifts towards higher binding energy following anion substitution are attributed to increased electronegativity of the anion itself, while shifts towards lower binding energies following cation substitution are attributed to an increase in the cation-anion distance that causes a lower Coulombic binding potential. The predominant ionization mechanism in the near threshold photon energy region is identified as dissociative ionization, involving dissociation of the ion-pair and the production of intact cations as the positively charged products.

  20. A Fractional Characteristic Study of Liquid and Vapor Interface in Lennard—Jones Fluids

    Institute of Scientific and Technical Information of China (English)

    LIUChao; ZENGDanling

    2002-01-01

    The molecular dynamic simulation results for the liquid-vapor interface of the pure Lennard-Jones fluid are presented.The thermodynamic properties,the surface tension and the effective thickness of interfacial layer are determined.The rough characteristic of the liquid-vapor interface is discussed with fractional Brownian motion theory.Thereupon the fractal dimension d of the liqud-vapor interface is obtained.

  1. Liquid-vapor coexistence in a primitive model for a room-temperature ionic liquid.

    Science.gov (United States)

    Martín-Betancourt, Marianela; Romero-Enrique, José M; Rull, Luis F

    2009-07-09

    We present a primitive model for a room-temperature ionic liquid, where the cation is modeled as a charged hard spherocylinder of diameter sigma and length l and the anion as a charged hard sphere of diameter sigma. Liquid-vapor coexistence curves and critical parameters for this model have been studied by grand-canonical Monte Carlo methods. Our results show a decrease of both the critical temperature and density as the cation length l increases. These results are in qualitative agreement with recent experimental estimates of the critical parameters.

  2. Measurement of vapor-liquid-liquid phase equilibrium-Equipment and results

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; von Solms, Nicolas; Richon, Dominique;

    2015-01-01

    -water-gas hydrate inhibitor systems, at temperatures ranging from 283 to 353 K and at pressures up to 40 MPa. The core of the equipment is an equilibrium cell, equipped with sapphire windows and connected to an analytical system by capillary samplers.New vapor-liquid-liquid equilibrium data are reported for methane......+ n-hexane + methanol + water at 296.2 K and pressures of 6 to 10 MPa. The Cubic-Plus-Association (CPA) equation of state is used to model the phase equilibria data measured. A good agreement between predictions and experimental data is observed, supporting the reliability of the new data. (C) 2015...

  3. Non-aqueous phase liquid spreading during soil vapor extraction

    Science.gov (United States)

    Kneafsey, Timothy J.; Hunt, James R.

    2004-02-01

    Many non-aqueous phase liquids (NAPLs) are expected to spread at the air-water interface, particularly under non-equilibrium conditions. In the vadose zone, this spreading should increase the surface area for mass transfer and the efficiency of volatile NAPL recovery by soil vapor extraction (SVE). Observations of spreading on water wet surfaces led to a conceptual model of oil spreading vertically above a NAPL pool in the vadose zone. Analysis of this model predicts that spreading can enhance the SVE contaminant recovery compared to conditions where the liquid does not spread. Experiments were conducted with spreading volatile oils hexane and heptane in wet porous media and capillary tubes, where spreading was observed at the scale of centimeters. Within porous medium columns up to a meter in height containing stagnant gas, spreading was less than ten centimeters and did not contribute significantly to hexane volatilization. Water film thinning and oil film pinning may have prevented significant oil film spreading, and thus did not enhance SVE at the scale of a meter. The experiments performed indicate that volatile oil spreading at the field scale is unlikely to contribute significantly to the efficiency of SVE.

  4. Correlation of vapor-liquid equilibrium ratio of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Z.L.; Greenkorn, R.A.; Chao, K.C. [Purdue Univ., West Lafayette, IN (United States). School of Chemical Engineering

    1995-06-01

    In this work the correlation of vapor-liquid equilibrium ratio of hydrogen in the Chao-Seader correlation is updated with the use of new experimental data that have appeared in the intervening years. The correlation is extended in the direction of high temperature where much new data have been reported over a wide pressure range. The hydrogen correlation in the Chao-Seader correlation was based on experimental data in the temperature range of approximately 200--530 K that was the full extent of available data at the time. Grayson and Streed (1963) extended the hydrogen correlation to higher temperature using proprietary data on oil fractions. Since then a great deal of experimental investigation has been performed to determine the solubility of hydrogen at temperatures up to 730 K and pressure up to 25 MPa. Sebastian and coworkers (1981) developed a correlation for the solubility of hydrogen based on the expanded database. In this work the authors develop a new equation for the standard state liquid fugacity of hydrogen based on the expanded current database. The new equation will be useful to replace the equation for v of hydrogen in the Chao-Seader correlation that is found in process design software packages.

  5. What am I? Supercooled droplet or ice?

    CERN Document Server

    Antonini, Carlo; Maitra, Tanmoy; Tiwari, Manish K; Poulikakos, Dimos

    2013-01-01

    In this fluid dynamics video we show the trick played by a supercooled liquid water drop against a superhydrophobic surface. The water drop shows a double personality, impacting onto the surface the first time while still in the liquid state, and then re-impacting as a frozen ice crystal.

  6. Isothermal (liquid + liquid) equilibrium data at T = 313.15 K and isobaric (vapor + liquid + liquid) equilibrium data at 101.3 kPa for the ternary system (water + 1-butanol + p-xylene)

    OpenAIRE

    Gomis Yagües, Vicente; Font Escamilla, Alicia; Saquete Ferrándiz, María Dolores; García Cano, Jorge

    2014-01-01

    The (vapor + liquid), (liquid + liquid) and (vapor + liquid + liquid) equilibria of the ternary system (water + 1-butanol + p-xylene) have been determined. (Water + 1-butanol + p-xylene) is a type 2 heterogeneous ternary system with partially miscible (water + 1-butanol) and (water + p-xylene) pairs. By contrast, (1-butanol + p-xylene) is totally miscible under atmospheric conditions. This paper examines the (vapor + liquid) equilibrium in both heterogeneous and homogeneous regions at 101.3 k...

  7. Chemical hazards present in liquids and vapors of electronic cigarettes.

    Science.gov (United States)

    Hutzler, Christoph; Paschke, Meike; Kruschinski, Svetlana; Henkler, Frank; Hahn, Jürgen; Luch, Andreas

    2014-07-01

    Electronic (e-)cigarettes have emerged in recent years as putative alternative to conventional tobacco cigarettes. These products do not contain typical carcinogens that are present in tobacco smoke, due to the lack of combustion. However, besides nicotine, hazards can also arise from other constituents of liquids, such as solvents, flavors, additives and contaminants. In this study, we have analyzed 28 liquids of seven manufacturers purchased in Germany. We confirm the presence of a wide range of flavors to enhance palatability. Although glycerol and propylene glycol were detected in all samples, these solvents had been replaced by ethylene glycol as dominant compound in five products. Ethylene glycol is associated with markedly enhanced toxicological hazards when compared to conventionally used glycerol and propylene glycol. Additional additives, such as coumarin and acetamide, that raise concerns for human health were detected in certain samples. Ten out of 28 products had been declared "free-of-nicotine" by the manufacturer. Among these ten, seven liquids were identified containing nicotine in the range of 0.1-15 µg/ml. This suggests that "carry over" of ingredients may occur during the production of cartridges. We have further analyzed the formation of carbonylic compounds in one widely distributed nicotine-free brand. Significant amounts of formaldehyde, acetaldehyde and propionaldehyde were only found at 150 °C by headspace GC-MS analysis. In addition, an enhanced formation of aldehydes was found in defined puff fractions, using an adopted machine smoking protocol. However, this effect was delayed and only observed during the last third of the smoking procedure. In the emissions of these fractions, which represent up to 40 % of total vapor volume, similar levels of formaldehyde were detected when compared to conventional tobacco cigarettes. By contrast, carbonylic compounds were hardly detectable in earlier collected fractions. Our data demonstrate the

  8. 40 CFR 264.1057 - Standards: Valves in gas/vapor service or in light liquid -service.

    Science.gov (United States)

    2010-07-01

    ...: Valves in gas/vapor service or in light liquid -service. (a) Each valve in gas/vapor or light liquid... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service or in light liquid -service. 264.1057 Section 264.1057 Protection of Environment...

  9. 40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

    Science.gov (United States)

    2010-07-01

    ... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups...

  10. Impact of Liquid-Vapor to Liquid-Liquid-Vapor Phase Transitions on Asphaltene-Rich Nanoaggregate Behavior in Athabasca Vacuum Residue + Pentane Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Long, Bingwen; Chodakowski, Martin; Shaw, John M. [Alberta; (Beijing U)

    2013-06-05

    The bulk phase behavior of heavy oil + alkane mixtures and the behavior of the asphaltenes that they contain are topics of importance for the design and optimization of processes for petroleum production, transport, and refining and for performing routine saturates, aromatics, resins, and asphaltenes (SARA) analyses. In prior studies, partial phase diagrams and phase behavior models for Athabasca vacuum residue (AVR) comprising 32 wt % pentane asphaltenes + n-alkanes were reported. For mixtures with pentane, observed phase behaviors included single-phase liquid as well as liquid–liquid, liquid–liquid–vapor, and liquid–liquid–liquid–vapor regions. Dispersed solids were detected under some conditions as well but not quantified. In this work, small-angle X-ray scattering (SAXS) is used to study nanostructured materials in liquid phases present in AVR + n-pentane mixtures from 50 to 170 °C at mixture bubble pressure. The investigation focuses on the impact of the transition from a single AVR-rich liquid to co-existing pentane-rich and AVR-rich liquids on the nanostructure and the nanostructures most resistant to aggregation as the pentane composition axis is approached. Background scattering subtraction was performed using global mixture composition. The robustness of this assumption with respect to values obtained for coefficients appearing in a two level Beaucage unified equation fit is demonstrated. The nanostructured material is shown to arise at two length scales from 1 to 100 wt % AVR. Smaller nanostructures possess mean radii less than 50 Å, while the larger nanostructures possess mean radii greater than 250 Å. The addition of pentane to the AVR causes an increasingly large fraction of the large and small nanostructures to grow in size. Only nanostructures resistant to aggregation remain in the pentane-rich phase as the 0 wt % AVR axis is approached. Step changes in aggregation identified from changes in average radius of gyration, scattering

  11. Stability limit of liquid water in metastable equilibrium with subsaturated vapors.

    Science.gov (United States)

    Wheeler, Tobias D; Stroock, Abraham D

    2009-07-07

    A pure liquid can reach metastable equilibrium with its subsaturated vapor across an appropriate membrane. This situation is analogous to osmotic equilibrium: the reduced chemical potential of the dilute phase (the subsaturated vapor) is compensated by a difference in pressure between the phases. To equilibrate with subsaturated vapor, the liquid phase assumes a pressure that is lower than its standard vapor pressure, such that the liquid phase is metastable with respect to the vapor phase. For sufficiently subsaturated vapors, the liquid phase can even assume negative pressures. The appropriate membrane for this metastable equilibrium must provide the necessary mechanical support to sustain the difference in pressure between the two phases, limit nonhomogeneous mechanisms of cavitation, and resist the entry of the dilutant (gases) into the pure phase (liquid). In this article, we present a study of the limit of stability of liquid water--the degree of subsaturation at which the liquid cavitates--in this metastable state within microscale voids embedded in hydrogel membranes. We refer to these structures as vapor-coupled voids (VCVs). In these VCVs, we observed that liquid water cavitated when placed in equilibrium with vapors of activity aw,vapairliquid based on thermodynamic calculations, the liquid cavitated at pressures Pvapor nuclei, and (iv) invasion of air through the hydrogel membrane into the voids. We conclude

  12. Evidence for a liquid-liquid critical point in supercooled water within the E3B3 model and a possible interpretation of the kink in the homogeneous nucleation line

    Science.gov (United States)

    Ni, Yicun; Skinner, J. L.

    2016-06-01

    Supercooled water exhibits many thermodynamic anomalies, and several scenarios have been proposed to interpret them, among which the liquid-liquid critical point (LLCP) hypothesis is the most commonly discussed. We investigated Widom lines and the LLCP of deeply supercooled water, by using molecular dynamics simulation with a newly reparameterized water model that explicitly includes three-body interactions. Seven isobars are studied from ambient pressure to 2.5 kbar, and Widom lines are identified by calculating maxima in the coefficient of thermal expansion and the isothermal compressibility (both with respect to temperature). From these data we estimate that the LLCP of the new water model is at 180 K and 2.1 kbar. The oxygen radial distribution function is calculated along the 2 kbar isobar. It shows a steep change in the height of its second peak between 180 and 185 K, which indicates a transition between the high-density liquid and low-density liquid phases and which is consistent with the ascribed location of the critical point. The good agreement of the height of the second peak of the radial distribution function between simulation and experiment at 1 bar, as a function of temperature, supports the validity of the model. The location of the LLCP within the model is close to the kink in the experimental homogeneous nucleation line. We use existing experimental data to argue that the experimental LLCP is at 168 K and 1.95 kbar and speculate how this LLCP and its Widom line might be responsible for the kink in the homogeneous nucleation line.

  13. Evidence for a liquid-liquid critical point in supercooled water within the E3B3 model and a possible interpretation of the kink in the homogeneous nucleation line.

    Science.gov (United States)

    Ni, Yicun; Skinner, J L

    2016-06-07

    Supercooled water exhibits many thermodynamic anomalies, and several scenarios have been proposed to interpret them, among which the liquid-liquid critical point (LLCP) hypothesis is the most commonly discussed. We investigated Widom lines and the LLCP of deeply supercooled water, by using molecular dynamics simulation with a newly reparameterized water model that explicitly includes three-body interactions. Seven isobars are studied from ambient pressure to 2.5 kbar, and Widom lines are identified by calculating maxima in the coefficient of thermal expansion and the isothermal compressibility (both with respect to temperature). From these data we estimate that the LLCP of the new water model is at 180 K and 2.1 kbar. The oxygen radial distribution function is calculated along the 2 kbar isobar. It shows a steep change in the height of its second peak between 180 and 185 K, which indicates a transition between the high-density liquid and low-density liquid phases and which is consistent with the ascribed location of the critical point. The good agreement of the height of the second peak of the radial distribution function between simulation and experiment at 1 bar, as a function of temperature, supports the validity of the model. The location of the LLCP within the model is close to the kink in the experimental homogeneous nucleation line. We use existing experimental data to argue that the experimental LLCP is at 168 K and 1.95 kbar and speculate how this LLCP and its Widom line might be responsible for the kink in the homogeneous nucleation line.

  14. Using silicon diodes for detecting the liquid-vapor interface in hydrogen

    Science.gov (United States)

    Dempsey, Paula J.; Fabik, Richard H.

    1992-01-01

    Tests were performed using commercially available silicon diode temperature sensors to detect the location of the liquid-vapor interface in hydrogen during ground test programs. Results show that by increasing the current into the sensor, silicon diodes can be used as liquid level point sensors. After cycling the sensors from liquid to vapor several times, it was found that with a 30 mA (milliamps) input current, the sensors respond within 2 seconds by measuring a large voltage difference when transitioning from liquid to vapor across the interface. Nearly instantaneous response resulted during a transition from vapor to liquid. Detailed here are test procedures, experimental results, and guidelines for applying this information to other test facilities.

  15. Closed-loop liquid-vapor equilibrium in a one-component system.

    Science.gov (United States)

    Almarza, N G

    2012-09-01

    We report Monte Carlo simulations that show a closed-loop liquid-vapor equilibrium in a pure substance. This finding has been achieved on a two-dimensional lattice model for patchy particles that can form network fluids. We have considered related models with a slightly different patch distribution in order to understand the features of the distribution of patches on the surface of the particles that make possible the presence of the closed-loop liquid-vapor equilibrium, and its relation to the phase diagram containing so-called empty liquids. Finally we discuss the likelihood of finding the closed-loop liquid-vapor equilibria on related models for three-dimensional models of patchy particles in the continuum, and speculate on the possible relationship between the mechanism behind the closed-loop liquid-vapor equilibrium of our simple lattice model and the salt-induced reentrant condensation found in complex systems.

  16. Experimental analysis on adjusting performance of vapor-liquid two-phase flow controller

    Institute of Scientific and Technical Information of China (English)

    LI Hui-jun; TU Shan

    2006-01-01

    The vapor-liquid self-adjusting controller is an innovative automatic regulating valve. In order to ensure adjusted objects run safely and economically, the controller automatically adjusts the liquid flux to keep liquid level at a required level according to physical properties of vapor-liquid two-phase fluid. The adjusting mechanics, the controller' s performance and influencing factors of its stability have been analyzed in this paper. The theoretical analysis and successful applications have demonstrated this controller can keep the liquid level steady with good performance. The actual application in industry has shown that the controller can satisfactorily meet the requirement of industrial production and has wide application areas.

  17. Cold Model Study and Commercial Test on Novel Vapor-Liquid Distributor of Hydroprocessing Reactor

    Institute of Scientific and Technical Information of China (English)

    Wang Shaobing; Zhang Zhanzhu; Wu Defei; Guo Qingming

    2007-01-01

    A novel vapor-liquid distributor was developed on the basis of sufficient study on the existing distributors applied in hydroprocessing reactors.The cold model test data showed that the fluid distribution performance of the novel vapor-liquid distributor was evidently better than the traditional one.Commercial tests of the new distributor were carried out in the 300 kt/a gas oil hydrotreating reactor at SINOPEC Changling Branch Company,showing that the new vapor-liquid distributor could improve the fluid distribution,promote the hydrotreating efficiency and lead to better performance than the traditional one.

  18. Harvesting liquid from unsaturated vapor - nanoflows induced by capillary condensation

    Science.gov (United States)

    Vincent, Olivier; Marguet, Bastien; Stroock, Abraham

    2016-11-01

    A vapor, even subsaturated, can spontaneously form liquid in nanoscale spaces. This process, known as capillary condensation, plays a fundamental role in various contexts, such as the formation of clouds or the dynamics of hydrocarbons in the geological subsurface. However, large uncertainties remain on the thermodynamics and fluid mechanics of the phenomenon, due to experimental challenges as well as outstanding questions about the validity of macroscale physics at the nanometer scale. We studied experimentally the spatio-temporal dynamics of water condensation in a model nanoporous medium (pore radius 2 nm), taking advantage of the color change of the material upon hydration. We found that at low relative humidities (diffusive fashion, while it occurred through a well-defined capillary-viscous imbibition front at > 60 % RH, driven by a balance between the pore capillary pressure and the condensation stress given by Kelvin equation. Further analyzing the imbibition dynamics as a function of saturation allowed us to extract detailed information about the physics of nano-confined fluids. Our results suggest excellent extension of macroscale fluid dynamics and thermodynamics even in pores 10 molecules in diameter.

  19. Effects of cloud condensation nuclei and ice nucleating particles on precipitation processes and supercooled liquid in mixed-phase orographic clouds

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jiwen; Leung, L. Ruby; Rosenfeld, Daniel; DeMott, Paul J.

    2017-01-01

    How orographic mixed-phase clouds respond to the change in cloud condensation nuclei (CCN) and ice nucleating particles (INPs) are highly uncertain. The main snow production mechanism in warm and cold mixed-phase orographic clouds (referred to as WMOCs and CMOCs, respectively, distinguished here as those having cloud tops warmer and colder than -20°C) could be very different. We quantify the CCN and INP impacts on supercooled water content, cloud phases, and precipitation for a WMOC case and a CMOC case, with sensitivity tests using the same CCN and INP concentrations between the WMOC and CMOC cases. It was found that deposition plays a more important role than riming for forming snow in the CMOC case, while the role of riming is dominant in the WMOC case. As expected, adding CCN suppresses precipitation, especially in WMOCs and low INPs. However, this reverses strongly for CCN of 1000 cm-3 and larger. We found a new mechanism through which CCN can invigorate mixed-phase clouds over the Sierra Nevada and drastically intensify snow precipitation when CCN concentrations are high (1000 cm-3 or higher). In this situation, more widespread shallow clouds with a greater amount of cloud water form in the Central Valley and foothills west of the mountain range. The increased latent heat release associated with the formation of these clouds strengthens the local transport of moisture to the windward slope, invigorating mixed-phase clouds over the mountains, and thereby producing higher amounts of snow precipitation. Under all CCN conditions, increasing the INPs leads to decreased riming and mixed-phase fraction in the CMOC as a result of liquid-limited conditions, but has the opposite effects in the WMOC as a result of ice-limited conditions. However, precipitation in both cases is increased by increasing INPs due to an increase in deposition for the CMOC but enhanced riming and deposition in the WMOC. Increasing the INPs dramatically reduces

  20. Vaporization heat transfer of dielectric liquids on a wick-covered surface

    Science.gov (United States)

    Gu, C. B.; Chow, L. C.; Baker, K.

    1993-01-01

    Vaporization heat transfer characteristics were measured for the dielectric liquid FC-72 on a horizontal heated surface covered with wire screen wicks with the mesh number for the screens varying from 24 to 100. In such a situation the liquid level can be either higher or lower than the heated surface. When the liquid level was above the heated surface (shallow pool boiling), the height of the liquid level above the surface, h, was varied from 0 to 10 mm. When the liquid level was below the heated surface (evaporation through capillary pumping), the distance from the liquid level to the edge of the surface, L, was adjusted from 0 to 15 mm. Experimental data revealed that the critical heat flux (CHF) decreases as the mesh number is increased from 24 to 100 for both vaporation and shallow pool boiling, showing that the vapor-escaping limit is more important than the capillary limit in flat plate heat pipe application.

  1. Vaporization heat transfer of dielectric liquids on a wick-covered surface

    Science.gov (United States)

    Gu, C. B.; Chow, L. C.; Baker, K.

    1993-01-01

    Vaporization heat transfer characteristics were measured for the dielectric liquid FC-72 on a horizontal heated surface covered with wire screen wicks with the mesh number for the screens varying from 24 to 100. In such a situation the liquid level can be either higher or lower than the heated surface. When the liquid level was above the heated surface (shallow pool boiling), the height of the liquid level above the surface, h, was varied from 0 to 10 mm. When the liquid level was below the heated surface (evaporation through capillary pumping), the distance from the liquid level to the edge of the surface, L, was adjusted from 0 to 15 mm. Experimental data revealed that the critical heat flux (CHF) decreases as the mesh number is increased from 24 to 100 for both vaporation and shallow pool boiling, showing that the vapor-escaping limit is more important than the capillary limit in flat plate heat pipe application.

  2. Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential

    Science.gov (United States)

    Keddy, Chris P.

    2012-01-01

    Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE.

  3. Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures

    Directory of Open Access Journals (Sweden)

    B. A. Mandagarán

    2006-03-01

    Full Text Available A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the correlation shows a good agreement for binary and ternary data. The correlation also shows good prediction for reactive quaternary data.

  4. The effect of capillary pressure for concave liquid-vapor interface on interfacial evaporation

    Institute of Scientific and Technical Information of China (English)

    张金涛; 王补宣; 彭晓峰

    2001-01-01

    The analysis in this paper demonstrates that the capillary pressure on the concave liquid-vapor interface will promote the interfacial evaporation, therefore clarifying the confusion over the great difference between the estimated and real rate of interfacial evaporation. This difference increases with decreasing capillary radius, and becomes more apparent for liquid with high latent heat. The present analysis also shows that the capillary pressure on the concave interface will result in a decrease in liquid phase equilibrium temperature, which can explain the possibility of vapor bubble formation on micro liquid layer interfacial evaporation under low superheat, or even below the nominal saturated temperature.

  5. Vapor-liquid equilibria of coal-derived liquids; 3: Binary systems with tetralin at 200 mmHg

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, B.; Beltran, S.; Cabezas, J.L. (University Coll., Burgos (Spain). Dept. of Chemical Engineering); Coca, J. (Univ. of Oviedo (Spain). Dept. of Chemical Engineering)

    1994-01-01

    Isobaric vapor-liquid equilibrium data are reported for binary systems of tetralin with p-xylene, [gamma]-picoline, piperidine, and pyridine; all systems were measured at 26.66 kPa (200 mmHg) with a recirculation still. Liquid-phase activity coefficients were correlated using the Van Laar, Wilson, NRTL, and UNIQUAC equations. Vapor-phase nonidealities were found negligible under the experimental conditions of this work, and deviations of the liquid phase from the ideal behavior, as described by Raoult's law, were found to be slightly positive for all the systems.

  6. 40 CFR 60.482-7 - Standards: Valves in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... Before November 7, 2006 § 60.482-7 Standards: Valves in gas/vapor service and in light liquid service. (a... operation in gas/vapor service or light liquid service after the initial startup date for the process unit... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor...

  7. 40 CFR 63.1006 - Valves in gas and vapor service and in light liquid service standards.

    Science.gov (United States)

    2010-07-01

    ... § 63.1006 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... requested by the Administrator. For each such demonstration, all valves in gas and vapor and light liquid... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Valves in gas and vapor service and...

  8. 40 CFR 265.1057 - Standards: Valves in gas/vapor service or in light liquid service.

    Science.gov (United States)

    2010-07-01

    ....1057 Standards: Valves in gas/vapor service or in light liquid service. (a) Each valve in gas/vapor or... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service or in light liquid service. 265.1057 Section 265.1057 Protection of Environment...

  9. Using Si Diodes To Detect H2 Liquid/Vapor Interfaces

    Science.gov (United States)

    Dempsey, Paula Jean; Fabik, Richard

    1994-01-01

    Commercially available silicon-diode temperature sensors used to detect interfaces between hydrogen liquid and hydrogen vapor at steady-state saturation conditions. Sensors mounted at short intervals along rod to form rake-like array. Array inserted in tank with rod oriented vertically, where it senses level of liquid hydrogen to resolution equal to interval between sensors. Basic idea to measure voltage across sensor while supplying small electric current that heats sensor. Because vapor cools sensor less effectively than liquid does, sensor's steady-state temperature greater when sensor surrounded by vapor than when immersed in liquid. Voltage output decreases as temperature increases for silicon diodes. Thus, temperature (voltage) reading used to determine whether liquid level above or below sensor.

  10. Adsorption kinetics of surfactants at liquid-solid and liquid-vapor interfaces from atomic-scale simulations

    Science.gov (United States)

    Iskrenova, Eugeniya K.; Patnaik, Soumya S.

    2012-02-01

    Nucleate pool boiling of pure liquid is a complex process involving different size- and time-scale phenomena. The appearance of the first nanobubble in the liquid at the bottom of a hot pan, the detachment of the bubble from the solid surface, its subsequent coalescence with other bubbles, all represent complex multiscale phenomena. Surfactants added to water increase the complexity of the process by contributing to the dynamic surface tension at the liquid-vapor and liquid-solid interfaces and thus affecting the heat and mass transfer at those interfaces. We apply molecular dynamics simulations to study the adsorption kinetics of anionic, cationic, and non-ionic surfactants at liquid/solid and liquid/vapor interfaces. The all-atom vs. united-atom approaches for the solid and surfactants are surveyed in view of their applicability at near boiling temperatures and a range of model water potentials is assessed for reproducing the thermal properties of water at boiling conditions.

  11. Vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria calculations for polystyrene plus methyleyclohexane and polystyrene plus cyclohexane solutions

    DEFF Research Database (Denmark)

    Wilczura-Wachnik, H.; Jonsdottir, Svava Osk

    2006-01-01

    This paper presents the vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria predictions for polystyrene in two theta solvents: cyclohexane and methylcyclohexane. VLE calculations were performed with the Elbro free volume method and a modified version of the PC-SAFT method, as well...

  12. Investigation of vapor film motion regularities at boiling liquids

    Directory of Open Access Journals (Sweden)

    Zeigarnik Y.U.

    2013-04-01

    Full Text Available The experimental investigation of the saturated Freon-113 and distilled water film boiling on spheres with different diameters at atmospheric pressure under conditions of free convection is executed. With high-speed video average thickness and cumulative distribution function of vapor film as a function of the angle was measured. It was found that with increasing the angle the average thickness of vapor film can change by different laws depending on diameter of the sphere and the temperature difference. It was found also that the increase in the average vapor film thickness with increasing angle is more connected with the increase of large components of cumulative distribution function. It also noted the presence of quasi-periodic pulsations of the vapor film thickness in the lower part, which eventually largely determine the behavior of the interface at large angles.

  13. Design, fabrication and performance evaluation of a vaporizing liquid microthruster

    Science.gov (United States)

    Kundu, Pijus; Kanti Bhattacharyya, Tarun; Das, Soumen

    2012-02-01

    A recent application domain of MEMS technology is in the development of microthrusters for micro-/nanosatellites. Among the various types of MEMS microthruster developed so far, the vaporizing liquid microthruster (VLM) has been widely explored for its capability to produce continuously variable thrust in the micro-Newton (µN) to mili-Newton (mN) range. This paper reports the design and experimental validation of silicon MEMS VLM consisting of a microcavity, inlet channel and converging-diverging (C-D) in-plane exit nozzle integrated in two micromachined bonded chips and sandwiched between two p-diffused microheaters, located at the top and bottom surface of the device. Structural configuration was designed using simple analytical equations to achieve maximum thrust force by controlling the inlet propellant flow and heater power of VLM in an efficient way. In addition, a 3D model using a computational fluid dynamics technique was constructed to simulate the aft section of VLM for the investigation of its aerodynamic behavior. The device fabrication and testing have been briefly described. The fabricated VLM is capable to produce 1 mN thrust using maximum heater power of 3.6 W at a water flow rate of 2.04 mg s-1 using an in-plane C-D exit nozzle of throat area 130 µm × 100 µm. A detailed thrust force measurement was carried out with the variation of input heater power for different mass flow conditions and exit to throat area ratio of the exit nozzle, and the results were interpreted with the theoretical model. The model gives considerable physical insight in the operation of the VLM. Finally, a performance comparison with other published VLM results indicates that the present design can yield comparatively more thrust force with much less input power. A performance comparison with other published VLM results indicates that the present design can achieve improved performance by integrating two heaters with appropriate chamber volume in respect of propellant flow

  14. Molecular dynamics study on condensation/evaporation coefficients of chain molecules at liquid-vapor interface.

    Science.gov (United States)

    Nagayama, Gyoko; Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu

    2015-07-07

    The structure and thermodynamic properties of the liquid-vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid-vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid-vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid-vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid-vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.

  15. Universal adsorption at the vapor-liquid interface near the consolute point

    Science.gov (United States)

    Schmidt, James W.

    1990-01-01

    The ellipticity of the vapor-liquid interface above mixtures of methylcyclohexane (C7H14) and perfluoromethylcyclohexane (C7F14) has been measured near the consolute point T(c) = 318.6 K. The data are consistent with a model of the interface that combines a short-ranged density-vs height profile in the vapor phase with a much longer-ranged composition-versus-height profile in the liquid. The value of the free parameter produced by fitting the model to the data is consistent with results from two other simple mixtures and a mixture of a polymer and solvent. This experiment combines precision ellipsometry of the vapor-liquid interface with in situ measurements of refractive indices of the liquid phases, and it precisely locates the consolute point.

  16. Interplay of vapor adsorption and liquid imbibition in nanoporous Vycor glass

    Science.gov (United States)

    Kiepsch, Sebastian; Pelster, Rolf

    2016-04-01

    We have studied the kinetics of spontaneous capillary rise and of the concurrent vapor adsorption in nanoporous, monolithic samples of Vycor glass with a mean pore diameter of 7.5 nm. As liquids, we have chosen n -alcohols (n =4 -10 ) whose vapor pressures at room temperature range from p0=965 Pa down to p0=0.743 Pa. Dielectric measurements allow us to achieve spatial selectivity to predefined parts of the porous Vycor glass. In this way, we are able to measure the overall uptake of molecules as well as vapor adsorption from the surroundings in unfilled parts of the pore network, i.e., above the liquid menisci of the rising imbibition front. We show that the latter process is unaltered compared to free adsorption in samples suspended above a liquid reservoir. Only at low vapor pressures, i.e., for long alcohols, vapor adsorption can be neglected and the capillary rise follows the theoretical predictions of the Lucas-Washburn √{t } law. The more volatile the alcohol, the more important the additional adsorption of molecules becomes. We show that the overall filling process in the pore network is well described by a superposition of the Lucas-Washburn law and the measured vapor adsorption. In addition, the experiments give insight into the vapor diffusion dynamics in the porous matrix.

  17. Temperature dependence of local solubility of hydrophobic molecules in the liquid-vapor interface of water.

    Science.gov (United States)

    Abe, Kiharu; Sumi, Tomonari; Koga, Kenichiro

    2014-11-14

    One important aspect of the hydrophobic effect is that solubility of small, nonpolar molecules in liquid water decreases with increasing temperature. We investigate here how the characteristic temperature dependence in liquid water persists or changes in the vicinity of the liquid-vapor interface. From the molecular dynamics simulation and the test-particle insertion method, the local solubility Σ of methane in the liquid-vapor interface of water as well as Σ of nonpolar solutes in the interface of simple liquids are calculated as a function of the distance z from the interface. We then examine the temperature dependence of Σ under two conditions: variation of Σ at fixed position z and that at fixed local solvent density around the solute molecule. It is found that the temperature dependence of Σ at fixed z depends on the position z and the system, whereas Σ at fixed local density decreases with increasing temperature for all the model solutions at any fixed density between vapor and liquid phases. The monotonic decrease of Σ under the fixed-density condition in the liquid-vapor interface is in accord with what we know for the solubility of nonpolar molecules in bulk liquid water under the fixed-volume condition but it is much robust since the solvent density to be fixed can be anything between the coexisting vapor and liquid phases. A unique feature found in the water interface is that there is a minimum in the local solubility profile Σ(z) on the liquid side of the interface. We find that with decreasing temperature the minimum of Σ grows and at the same time the first peak in the oscillatory density profile of water develops. It is likely that the minimum of Σ is due to the layering structure of the free interface of water.

  18. Vapor pressure of ionic liquids at low temperatures from AC-chip-calorimetry.

    Science.gov (United States)

    Ahrenberg, Mathias; Beck, Martin; Neise, Christin; Keßler, Olaf; Kragl, Udo; Verevkin, Sergey P; Schick, Christoph

    2016-08-03

    The very low vapor pressure of ionic liquids is challenging to measure. At elevated temperatures the liquids might start to decompose, and at relatively low temperatures the vapor pressure becomes too low to be measured by conventional methods. In this work we developed a highly sensitive method for mass loss determination at temperatures starting from 350 K. This technique is based on an alternating current calorimeter equipped with a chip sensor that consists of a free-standing SiNx-membrane (thickness measuring area with lateral dimensions of the order of 1 mm. A small droplet (diameter ca. 600 μm) of an ionic liquid is vaporized isothermally from the chip sensor in a vacuum-chamber. The surface-to-volume-ratio of such a droplet is large and the relative mass loss due to evaporation is therefore easy to monitor by the changing heat capacity (J K(-1)) of the remaining liquid. The vapor pressure is determined from the measured mass loss rates using the Langmuir equation. The method was successfully tested for the determination of the vapor pressure and the vaporization enthalpy of an archetypical ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][NTf2]). The data set created in this way in an extremely broad temperature range from 358 K to 780 K has allowed the estimation of the boiling temperature of [EMIm][NTf2]. The value (1120 ± 50) K should be considered as the first reliable boiling point of the archetypical ionic liquid obtained from experimental vapor pressures measured in the most possible close proximity to the normal boiling temperature.

  19. Diffuse-interface modeling of liquid-vapor coexistence in equilibrium drops using smoothed particle hydrodynamics.

    Science.gov (United States)

    Sigalotti, Leonardo Di G; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

    2014-07-01

    We study numerically liquid-vapor phase separation in two-dimensional, nonisothermal, van der Waals (vdW) liquid drops using the method of smoothed particle hydrodynamics (SPH). In contrast to previous SPH simulations of drop formation, our approach is fully adaptive and follows the diffuse-interface model for a single-component fluid, where a reversible, capillary (Korteweg) force is added to the equations of motion to model the rapid but smooth transition of physical quantities through the interface separating the bulk phases. Surface tension arises naturally from the cohesive part of the vdW equation of state and the capillary forces. The drop models all start from a square-shaped liquid and spinodal decomposition is investigated for a range of initial densities and temperatures. The simulations predict the formation of stable, subcritical liquid drops with a vapor atmosphere, with the densities and temperatures of coexisting liquid and vapor in the vdW phase diagram closely matching the binodal curve. We find that the values of surface tension, as determined from the Young-Laplace equation, are in good agreement with the results of independent numerical simulations and experimental data. The models also predict the increase of the vapor pressure with temperature and the fitting to the numerical data reproduces very well the Clausius-Clapeyron relation, thus allowing for the calculation of the vaporization pressure for this vdW fluid.

  20. Microspheres for the Growth of Silicon Nanowires via Vapor-Liquid-Solid Mechanism

    Directory of Open Access Journals (Sweden)

    Arancha Gómez-Martínez

    2014-01-01

    Full Text Available Silicon nanowires have been synthesized by a simple process using a suitable support containing silica and carbon microspheres. Nanowires were grown by thermal chemical vapor deposition via a vapor-liquid-solid mechanism with only the substrate as silicon source. The curved surface of the microsized spheres allows arranging the gold catalyst as nanoparticles with appropriate dimensions to catalyze the growth of nanowires. The resulting material is composed of the microspheres with the silicon nanowires attached on their surface.

  1. Effect of asymmetric gravity jitter excited slosh waves at liquid-vapor interface under microgravity

    Science.gov (United States)

    Hung, R. J.; Pan, H. L.; Lee, C. C.; Leslie, F. W.

    1992-01-01

    The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations, in particular the effect of surface tension on partially-filled rotating fluids (cryogenic liquid helium and helium vapor) in a sub-scale Gravity Probe-B Spacecraft propellant dewar tank imposed by time-dependent various directions of background gravity environment have been investigated. Results show that lower frequency gravity jitter imposed on the time-dependent variations of the direction of background gravity induced a greater amplitude of oscillations and a stronger degree of asymmetry in liquid-vapor interface geometry than that made by the higher frequency gravity jitter. Furthermore, the greater the components of background gravity in radial and circumferential directions will provide a greater contribution in driving more to the increasing amplitude and degrees of symmetry of liquid-vapor interface profiles which, in turn, modify the disturbance of moment of inertia and angular momentum of spacecraft.

  2. Liquid-vapor interface of the Stockmayer fluid in a uniform external field.

    Science.gov (United States)

    Moore, Stan G; Stevens, Mark J; Grest, Gary S

    2015-02-01

    The effect of a uniform (nonspatially varying) external field on the liquid-vapor interface of the Stockmayer fluid (Lennard-Jones particles embedded with a point dipole) has been investigated by molecular-dynamics simulations. The long-ranged parts of both the dipole and Lennard-Jones interactions are treated using an Ewald summation, which removes the effects of the cutoff. The direction of the field shifts the critical point and interfacial properties in different directions. For an external field parallel to the interface, the critical temperature increases, while for a field applied perpendicular to the interface, it decreases. The effects of the field on surface tension and interfacial width are also investigated. For zero field, dipoles near the liquid-vapor interface show a weak orientation parallel to the interface. For fields parallel to the interface, ordering in the liquid phase is greater than the vapor, while for fields perpendicular to the interface, the opposite is true.

  3. Vapor-like liquid coexistence densities affect the extension of the critical point's influence zone

    CERN Document Server

    Rivera, Jose Luis; Guerra-Gonzalez, Roberto

    2015-01-01

    The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone range covers up to hundreds of degrees below the critical temperature. Here we show that for a simple molecular potential of ethane, the critical influence zone covers a wide zone of tens of degrees (below the critical temperature) down to a transition temperature, at which the apparent critical influence zone vanishes and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, the experimentally observed wide extension of the critical influence zone is due to a vapor-like effect ...

  4. Heats of vaporization of room temperature ionic liquids by tunable vacuum ultraviolet photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; To, Albert; Koh, Christine; Strasser, Daniel; Kostko, Oleg; Leone, Stephen R.

    2009-11-25

    The heats of vaporization of the room temperature ionic liquids (RTILs) N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide, N-butyl-N-methylpyrrolidinium dicyanamide, and 1-butyl-3-methylimidazolium dicyanamide are determined using a heated effusive vapor source in conjunction with single photon ionization by a tunable vacuum ultraviolet synchrotron source. The relative gas phase ionic liquid vapor densities in the effusive beam are monitored by clearly distinguished dissociative photoionization processes via a time-of-flight mass spectrometer at a tunable vacuum ultraviolet beamline 9.0.2.3 (Chemical Dynamics Beamline) at the Advanced Light Source synchrotron facility. Resulting in relatively few assumptions, through the analysis of both parent cations and fragment cations, the heat of vaporization of N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide is determined to be Delta Hvap(298.15 K) = 195+-19 kJ mol-1. The observed heats of vaporization of 1-butyl-3-methylimidazolium dicyanamide (Delta Hvap(298.15 K) = 174+-12 kJ mol-1) and N-butyl-N-methylpyrrolidinium dicyanamide (Delta Hvap(298.15 K) = 171+-12 kJ mol-1) are consistent with reported experimental values using electron impact ionization. The tunable vacuum ultraviolet source has enabled accurate measurement of photoion appearance energies. These appearance energies are in good agreement with MP2 calculations for dissociative photoionization of the ion pair. These experimental heats of vaporization, photoion appearance energies, and ab initio calculations corroborate vaporization of these RTILs as intact cation-anion ion pairs.

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

    OpenAIRE

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

    2013-01-01

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

  6. Diffusivity and hydrodynamic drag of nanoparticles at a vapor-liquid interface

    Science.gov (United States)

    Koplik, Joel; Maldarelli, Charles

    2017-02-01

    Measurements of the surface diffusivity of colloidal spheres translating along a vapor-liquid interface show an unexpected decrease in diffusivity, or increase in surface drag (from the Stokes-Einstein relation), when the particles situate further into the vapor phase. However, direct measurements of the surface drag from the colloid velocity due to an external force find the expected decrease with deeper immersion into the vapor. We perform molecular dynamics simulations of the diffusivity and force experiments for a nanoparticle with a small surface roughness at a vapor-liquid interface to examine the effect of contact line fluctuations. The drag calculated from both calculations agree and decrease as the particle positions further into the vapor. The surface drag is smaller than the bulk liquid drag due to the partial submersion into the liquid and the finite thickness of the interfacial zone relative to the nanoparticle size. We observe weak contact line fluctuations and transient pinning events, but these do not give rise to an anomalous increase in drag in this system.

  7. Motion of liquid plugs between vapor bubbles in capillary tubes: a comparison between fluids

    Science.gov (United States)

    Bertossi, Rémi; Ayel, Vincent; Mehta, Balkrishna; Romestant, Cyril; Bertin, Yves; Khandekar, Sameer

    2017-04-01

    Pulsating heat pipes (PHP) are now well-known devices in which liquid/vapor slug flow oscillates in a capillary tube wound between hot and cold sources. In this context, this paper focuses on the motion of the liquid plug, trapped between vapor bubbles, moving in capillary tubes, to try to better understand the thermo-physical phenomena involved in such devices. This study is divided into three parts. In the first part, an experimental study presents the evolution of the vapor pressure during the evaporation process of a liquid thin film deposited from a liquid plug flowing in a heated capillary tube: it is found that the behavior of the generated and removed vapor can be very different, according to the thermophysical properties of the fluids. In the second part, a transient model allows to compare, in terms of pressure and duration, the motion of a constant-length liquid plug trapped between two bubbles subjected to a constant difference of vapor pressure: the results highlight that the performances of the four fluids are also very different. Finally, a third model that can be considered as an improvement of the second one, is also presented: here, the liquid slug is surrounded by two vapor bubbles, one subjected to evaporation, the pressure in both bubbles is now a result of the calculation. This model still allows comparing the behaviors of the fluid. Even if our models are quite far from a complete model of a real PHP, results do indicate towards the applicability of different fluids as suitable working fluids for PHPs, particularly in terms of the flow instabilities which they generate.

  8. Reduction in the Vapor Pressure in Condensation on Cold Droplets of a Liquid

    Science.gov (United States)

    Bochkareva, E. M.; Nemtsev, V. A.; Sorokin, V. V.; Terekhov, V. V.; Terekhov, V. I.

    2016-05-01

    A physicomathematical model of the process of depressurization in a pure saturated and superheated vapor due to the injection of monodisperse cold droplets of a liquid has been developed. A cellular model has been developed that is based on solving the equation of heat conduction in a liquid phase and on the integral method for a gas phase in a spherically symmetric one-dimensional formulation. Numerical investigation has been carried out of the influence of the size and concentration of the droplets and of the initial parameters of the steam on the dynamics of depressurization during the vapor condensation on the droplets.

  9. Vapor-liquid equilibrium thermodynamics of N2 + CH4 - Model and Titan applications

    Science.gov (United States)

    Thompson, W. R.; Zollweg, John A.; Gabis, David H.

    1992-01-01

    A thermodynamic model is presented for vapor-liquid equilibrium in the N2 + CH4 system, which is implicated in calculations of the Titan tropospheric clouds' vapor-liquid equilibrium thermodynamics. This model imposes constraints on the consistency of experimental equilibrium data, and embodies temperature effects by encompassing enthalpy data; it readily calculates the saturation criteria, condensate composition, and latent heat for a given pressure-temperature profile of the Titan atmosphere. The N2 content of condensate is about half of that computed from Raoult's law, and about 30 percent greater than that computed from Henry's law.

  10. Isobaric vapor-liquid equilibria in the system methyl propanoate + n-butyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Susial, P.; Ortega, J. (Univ. de Las Palmas de Gran Canaria, Canary Islands (Spain). Lab. de Termodinamica y Fisicoquimica)

    1993-10-01

    Isobaric vapor-liquid equilibria were determined at 74.66, 101.32, and 127.99 kPa for binary mixtures containing methyl propanoate + n-butyl alcohol by using a dynamic still with vapor and liquid circulation. No azeotrope was detected. The data were found to be thermodynamically consistent according to the point to point test. Application of the group-contribution models ASOG, UNIFAC, and modified UNIFAC to the activity coefficients at the three pressures studied gives average errors of less than 10%, 11%, and 3%, respectively.

  11. Dynamic Evolution of the Evaporating Liquid-Vapor Interface in Micropillar Arrays.

    Science.gov (United States)

    Antao, Dion S; Adera, Solomon; Zhu, Yangying; Farias, Edgardo; Raj, Rishi; Wang, Evelyn N

    2016-01-19

    Capillary assisted passively pumped thermal management devices have gained importance due to their simple design and reduction in energy consumption. The performance of these devices is strongly dependent on the shape of the curved interface between the liquid and vapor phases. We developed a transient laser interferometry technique to investigate the evolution of the shape of the liquid-vapor interface in micropillar arrays during evaporation heat transfer. Controlled cylindrical micropillar arrays were fabricated on the front side of a silicon wafer, while thin-film heaters were deposited on the reverse side to emulate a heat source. The shape of the meniscus was determined using the fringe patterns resulting from interference of a monochromatic beam incident on the thin liquid layer. We studied the evolution of the shape of the meniscus on these surfaces under various operating conditions including varying the micropillar geometry and the applied heating power. By monitoring the transient behavior of the evaporating liquid-vapor interface, we accurately measured the absolute location and shape of the meniscus and calculated the contact angle and the maximum capillary pressure. We demonstrated that the receding contact angle which determines the capillary pumping limit is independent of the microstructure geometry and the rate of evaporation (i.e., the applied heating power). The results of this study provide fundamental insights into the dynamic behavior of the liquid-vapor interface in wick structures during phase-change heat transfer.

  12. Nonequilibrium kinetic boundary condition at the vapor-liquid interface of argon.

    Science.gov (United States)

    Ishiyama, Tatsuya; Fujikawa, Shigeo; Kurz, Thomas; Lauterborn, Werner

    2013-10-01

    A boundary condition for the Boltzmann equation (kinetic boundary condition, KBC) at the vapor-liquid interface of argon is constructed with the help of molecular dynamics (MD) simulations. The KBC is examined at a constant liquid temperature of 85 K in a wide range of nonequilibrium states of vapor. The present investigation is an extension of a previous one by Ishiyama, Yano, and Fujikawa [Phys. Rev. Lett. 95, 084504 (2005)] and provides a more complete form of the KBC. The present KBC includes a thermal accommodation coefficient in addition to evaporation and condensation coefficients, and these coefficients are determined in MD simulations uniquely. The thermal accommodation coefficient shows an anisotropic behavior at the interface for molecular velocities normal versus tangential to the interface. It is also found that the evaporation and condensation coefficients are almost constant in a fairly wide range of nonequilibrium states. The thermal accommodation coefficient of the normal velocity component is almost unity, while that of the tangential component shows a decreasing function of the density of vapor incident on the interface, indicating that the tangential velocity distribution of molecules leaving the interface into the vapor phase may deviate from the tangential parts of the Maxwell velocity distribution at the liquid temperature. A mechanism for the deviation of the KBC from the isotropic Maxwell KBC at the liquid temperature is discussed in terms of anisotropic energy relaxation at the interface. The liquid-temperature dependence of the present KBC is also discussed.

  13. Thermal-hydraulic behaviors of vapor-liquid interface due to arrival of a pressure wave

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akira; Fujii, Yoshifumi; Matsuzaki, Mitsuo [Tokyo Institute of Technology (Japan)

    1995-09-01

    In the vapor explosion, a pressure wave (shock wave) plays a fundamental role for triggering, propagation and enhancement of the explosion. Energy of the explosion is related to the magnitude of heat transfer rate from hot liquid to cold volatile one. This is related to an increasing rate of interface area and to an amount of transient heat flux between the liquids. In this study, the characteristics of transient heat transfer and behaviors of vapor film both on the platinum tube and on the hot melt tin drop, under same boundary conditions have been investigated. It is considered that there exists a fundamental mechanism of the explosion in the initial expansion process of the hot liquid drop immediately after arrival of pressure wave. The growth rate of the vapor film is much faster on the hot liquid than that on the solid surface. Two kinds of roughness were observed, one due to the Taylor instability, by rapid growth of the explosion bubble, and another, nucleation sites were observed at the vapor-liquid interface. Based on detailed observation of early stage interface behaviors after arrival of a pressure wave, the thermal fragmentation mechanism is proposed.

  14. Tunable Wavelength Soft Photoionization of Ionic Liquid Vapors (Preprint)

    Science.gov (United States)

    2009-11-18

    empirical methods to predict the physical properties of ionic liquids: An overview of recent developments. Zeitschrift Fur Physikalische Chemie...calculations. Zeitschrift Fur Physikalische Chemie- Preprint Distribution A: Approved for public release; distribution unlimited 13 International

  15. Modeling of Vapor-Liquid-Solid Equilibria in Acidic Aqueous Solutions

    DEFF Research Database (Denmark)

    Christensen, Søren Gregers; Thomsen, Kaj

    2003-01-01

    The phase behavior (vapor - liquid equilibria (VLE) and solid - liquid equilibria (SLE)) and thermal properties of aqueous solutions of ions like (K+, Na+, NH4+, Ca2+, Cl-) in the presence of phosphoric acid (H3PO4, H2PO4-, HPO42- ) and nitric acid (HNO3, NO3-) are described by means of the Exten......The phase behavior (vapor - liquid equilibria (VLE) and solid - liquid equilibria (SLE)) and thermal properties of aqueous solutions of ions like (K+, Na+, NH4+, Ca2+, Cl-) in the presence of phosphoric acid (H3PO4, H2PO4-, HPO42- ) and nitric acid (HNO3, NO3-) are described by means...

  16. 40 CFR 63.173 - Standards: Agitators in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... Equipment Leaks § 63.173 Standards: Agitators in gas/vapor service and in light liquid service. (a)(1) Each... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 63.173 Section 63.173 Protection of Environment...

  17. 40 CFR 65.109 - Standards: Agitators in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... Standards: Agitators in gas/vapor service and in light liquid service. (a) Compliance schedule. The owner or... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Agitators in gas/vapor service and in light liquid service. 65.109 Section 65.109 Protection of Environment...

  18. 40 CFR 60.482-7a - Standards: Valves in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ...-7a Standards: Valves in gas/vapor service and in light liquid service. (a)(1) Each valve shall be... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 60.482-7a Section 60.482-7a Protection of Environment...

  19. 40 CFR 63.1009 - Agitators in gas and vapor service and in light liquid service standards.

    Science.gov (United States)

    2010-07-01

    ... § 63.1009 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1009 Section 63.1009 Protection of Environment...

  20. 40 CFR 63.1025 - Valves in gas and vapor service and in light liquid service standards.

    Science.gov (United States)

    2010-07-01

    ... Standards § 63.1025 Valves in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Valves in gas and vapor service and in light liquid service standards. 63.1025 Section 63.1025 Protection of Environment...

  1. 40 CFR 63.174 - Standards: Connectors in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... Equipment Leaks § 63.174 Standards: Connectors in gas/vapor service and in light liquid service. (a) The... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 63.174 Section 63.174 Protection of Environment...

  2. 40 CFR 63.1008 - Connectors in gas and vapor service and in light liquid service standards.

    Science.gov (United States)

    2010-07-01

    ... § 63.1008 Connectors in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Connectors in gas and vapor service and in light liquid service standards. 63.1008 Section 63.1008 Protection of Environment...

  3. 40 CFR 63.1028 - Agitators in gas and vapor service and in light liquid service standards.

    Science.gov (United States)

    2010-07-01

    ... Standards § 63.1028 Agitators in gas and vapor service and in light liquid service standards. (a) Compliance... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Agitators in gas and vapor service and in light liquid service standards. 63.1028 Section 63.1028 Protection of Environment...

  4. 40 CFR 63.168 - Standards: Valves in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... § 63.168 Standards: Valves in gas/vapor service and in light liquid service. (a) The provisions of this section apply to valves that are either in gas service or in light liquid service. (1) The provisions are... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor...

  5. 40 CFR 65.108 - Standards: Connectors in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... Standards: Connectors in gas/vapor service and in light liquid service. (a) Compliance schedule. Except as... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Connectors in gas/vapor service and in light liquid service. 65.108 Section 65.108 Protection of Environment...

  6. 40 CFR 65.106 - Standards: Valves in gas/vapor service and in light liquid service.

    Science.gov (United States)

    2010-07-01

    ... Standards: Valves in gas/vapor service and in light liquid service. (a) Compliance schedule. (1) The owner... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Valves in gas/vapor service and in light liquid service. 65.106 Section 65.106 Protection of Environment ENVIRONMENTAL...

  7. X-ray scattering: Liquid metal/vapor interfaces

    Science.gov (United States)

    Pershan, P. S.

    2011-05-01

    We will review the principal x-ray scattering measurements that have been carried out on the free surface of liquid metals over the past two decades. For metals such as K, Ga, In Sn, Bi etc the surface induces well-defined layering with atomic spacing `d' that penetrates into the bulk a distance of the order of the bulk liquid correlation length. As a consequence the angular dependence of the surface structure factor observed by x-ray reflectivity displays a broad peak at wavevector transfer ˜ 2π/ d with a half width that is comparable to the width of the bulk liquid structure factor. Quantitative measurement of this surface structure factor requires correction for a singular Debye-Waller like effect arising from thermally excited capillary waves. For liquid metal alloys the layering is accompanied by chemical segregation (i.e. Gibbs absorption) that can be characterized from the energy dependence of the reflectivity. Particularly interesting are the temperature dependence and elasticity of the two-dimensional surface frozen phases that form on the surface of the Au82Si18 liquid eutectic. Surface freezing, although not observed near the eutectic points of alloys such as Au-Ge, Pd-Ge and Pd-Si, has been observed at the free surface of the glass forming alloy Au49Ag5.5Pd2.3Cu26.9Si16.3.

  8. Liquid-vapor equilibrium and interfacial properties of square wells in two dimensions

    Science.gov (United States)

    Armas-Pérez, Julio C.; Quintana-H, Jacqueline; Chapela, Gustavo A.

    2013-01-01

    Liquid-vapor coexistence and interfacial properties of square wells in two dimensions are calculated. Orthobaric densities, vapor pressures, surface tensions, and interfacial thicknesses are reported. Results are presented for a series of potential widths λ* = 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, where λ* is given in units of the hard core diameter σ. Critical and triple points are explored. No critical point was found for λ* Armas-Pérez et al. [unpublished] as a hexatic phase transition. It is located at reduced temperatures T* = 0.47 and 0.35 for λ* = 1.4 and 1.5, respectively. Properties such as the surface tension, vapor pressure, and interfacial thickness do not present any discontinuity at these points. This amorphous solid branch does not follow the corresponding state principle, which is only applied to liquids and gases.

  9. Vapor-Liquid Equilibria Using the Gibbs Energy and the Common Tangent Plane Criterion

    Science.gov (United States)

    Olaya, Maria del Mar; Reyes-Labarta, Juan A.; Serrano, Maria Dolores; Marcilla, Antonio

    2010-01-01

    Phase thermodynamics is often perceived as a difficult subject with which many students never become fully comfortable. The Gibbsian geometrical framework can help students to gain a better understanding of phase equilibria. An exercise to interpret the vapor-liquid equilibrium of a binary azeotropic mixture, using the equilibrium condition based…

  10. Liquid-Vapor Flow Regime Transitions for Spacecraft Heat Transfer Loops

    Science.gov (United States)

    1988-12-01

    heavenly bodies, in spite of their astonishing distances, than in the investigations of the movement of flowing water before our very eyes" Galileo ... Galilei 1564-1642 Motivation to Study MicroQravity Flow Reuimes The study of microgravity vapor-liquid flow regimes is motivated by the benefits of heat

  11. Vapor-Liquid-Solid Equilibria of Sulfur Dioxide in Aqueous Electrolyte Solutions

    DEFF Research Database (Denmark)

    Pereda, Selva; Thomsen, Kaj; Rasmussen, Peter

    2000-01-01

    The Extended UNIQUAC model for electrolyte systems, combined with the Soave-Redlich-Kwong equation of state is used to describe the complex vapor-liquid-solid equilibria of sulfur dioxide in electrolyte solutions. Model parameters based on 1500 experimental data points are presented. The paramete...

  12. Phosphorus- and boron-doped hydrogenated amorphous silicon films prepared using vaporized liquid cyclopentasilane

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Takashi, E-mail: mtakashi@jaist.ac.jp [Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292 (Japan); Takagishi, Hideyuki; Shen, Zhongrong; Ohdaira, Keisuke; Shimoda, Tatsuya [Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292 (Japan); Japan Science and Technology Agency, ALCA, Nomi, Ishikawa, 923-1211 (Japan)

    2015-08-31

    A simple, inexpensive method for fabricating a hydrogenated amorphous silicon (a-Si:H) film using thermal chemical vapor deposition from cyclopentasilane (CPS) at atmospheric pressure with a substrate temperature of 370 °C is described. The reactant gas was generated from liquid CPS by vaporization in the deposition chamber. The vaporized CPS gas was transformed immediately into a-Si:H film on a heated substrate. The a-Si:H films could be doped either n- or p-type by dissolving appropriate amounts of white phosphorus or decaborane, respectively, in the liquid CPS before vaporization. This process allows deposition of doped a-Si:H films of photovoltaic device-quality without the need for handling, storage, or transportation of large amounts of gaseous reactants. - Highlights: • B and P doped a-Si:H films made from liquid materials is presented. • Decaborane and white phosphorus is dissolved in the liquid materials. • A simple, inexpensive method for fabricating a-Si:H films using non-vacuum process. • The doped a-Si:H films with usable quality for photovoltaic devices are deposited.

  13. Vapor phase versus liquid phase grafting of meso-porous alumina

    NARCIS (Netherlands)

    Sripathi, V.G.P.; Mojet, B.L.; Nijmeijer, A.; Benes, N.E.

    2013-01-01

    Functionalization of meso-porous c-alumina has been performed by grafting of 3-Aminopropyltrimethoxysilane (3APTMS) simultaneously from either the liquid phase or from the vapor phase. In both cases, after grafting nitrogen physisorption indicates that the materials remain meso-porous with significa

  14. Modeling of vapor-liquid-solid equilibrium in gas - aqueous electrolyte systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter

    1999-01-01

    A thermodynamic model for the description of vapor-liquid-solid equilibria is introduced. This model is a combination of the extended UNIQUAC model for electrolytes and the Soave-Redlich-Kwong cubic equation of state. The model has been applied to aqueous systems containing ammonia and/or carbon...

  15. Vapor phase versus liquid phase grafting of meso-porous alumina

    NARCIS (Netherlands)

    Sripathi, V.G.P.; Mojet, Barbara; Nijmeijer, Arian; Benes, Nieck Edwin

    2013-01-01

    Functionalization of meso-porous c-alumina has been performed by grafting of 3-Aminopropyltrimethoxysilane (3APTMS) simultaneously from either the liquid phase or from the vapor phase. In both cases, after grafting nitrogen physisorption indicates that the materials remain meso-porous with

  16. Effect of the Thermocouple on Measuring the Temperature Discontinuity at a Liquid-Vapor Interface.

    Science.gov (United States)

    Kazemi, Mohammad Amin; Nobes, David S; Elliott, Janet A W

    2017-07-18

    The coupled heat and mass transfer that occurs in evaporation is of interest in a large number of fields such as evaporative cooling, distillation, drying, coating, printing, crystallization, welding, atmospheric processes, and pool fires. The temperature jump that occurs at an evaporating interface is of central importance to understanding this complex process. Over the past three decades, thermocouples have been widely used to measure the interfacial temperature jumps at a liquid-vapor interface during evaporation. However, the reliability of these measurements has not been investigated so far. In this study, a numerical simulation of a thermocouple when it measures the interfacial temperatures at a liquid-vapor interface is conducted to understand the possible effects of the thermocouple on the measured temperature and features in the temperature profile. The differential equations of heat transfer in the solid and fluids as well as the momentum transfer in the fluids are coupled together and solved numerically subject to appropriate boundary conditions between the solid and fluids. The results of the numerical simulation showed that while thermocouples can measure the interfacial temperatures in the liquid correctly, they fail to read the actual interfacial temperatures in the vapor. As the results of our numerical study suggest, the temperature jumps at a liquid-vapor interface measured experimentally by using a thermocouple are larger than what really exists at the interface. For a typical experimental study of evaporation of water at low pressure, it was found that the temperature jumps measured by a thermocouple are overestimated by almost 50%. However, the revised temperature jumps are still in agreement with the statistical rate theory of interfacial transport. As well as addressing the specific application of the liquid-vapor temperature jump, this paper provides significant insight into the role that heat transfer plays in the operation of thermocouples

  17. Corner wetting during the vapor-liquid-solid growth of faceted nanowires

    Science.gov (United States)

    Spencer, Brian; Davis, Stephen

    2016-11-01

    We consider the corner wetting of liquid drops in the context of vapor-liquid-solid growth of nanowires. Specifically, we construct numerical solutions for the equilibrium shape of a liquid drop on top of a faceted nanowire by solving the Laplace-Young equation with a free boundary determined by mixed boundary conditions. A key result for nanowire growth is that for a range of contact angles there is no equilibrium drop shape that completely wets the corner of the faceted nanowire. Based on our numerical solutions we determine the scaling behavior for the singular surface behavior near corners of the nanowire in terms of the Young contact angle and drop volume.

  18. A vapor-liquid-solid model for chemical vapor deposition growth of carbon nanotubes.

    Science.gov (United States)

    Jiang, Kaili; Feng, Chen; Liu, Kai; Fan, Shoushan

    2007-01-01

    Although carbon nanotubes (CNTs) with a variety of morphologies have been successfully synthesized, there is no clear physical picture of the growth process. Correspondingly, the growth mechanism is still not clear up to now. Here we suggest a VLS model for the growth process of CNTs, which involves a liquid or liquid-like state catalyst. The basic idea is that, due to the high thermal conductivity and nanometer size of the catalyst and the fast diffusion of carbon atoms in it, both the temperature and the carbon atom distribution across it are uniform. The supersaturation level can be expressed as a function of the carbon concentration and temperature, which determines the nucleation dynamics and growth kinetics. Based on this model, the growth rate equation was obtained to describe the growth kinetics of carbon nanotubes, which shows good accordance with the experimental results.

  19. Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Shiina Tatsuo

    2016-01-01

    Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

  20. Measurement and Correlation of Vapor-Liquid Equilibrium for Binary System 1,2-Epoxycyclohexane+1,2-Dichloroethane

    Institute of Scientific and Technical Information of China (English)

    周彩荣; 王海峰; 石晓华; 蒋登高

    2013-01-01

    Vapor-liquid equilibrium data (T, x, y) of binary system 1,2-epoxycyclohexane+1,2-dichloroethane were determined experimentally by using a modified ROSE-Williams equilibrium vaporization system at 101.33 kPa. The results show that this binary system does not have azeotropic point. The vapor-liquid equilibrium data are in thermodynamic consistency. The binary interaction parameters in the Wilson equation are presented with the correlation of vapor-liquid equilibrium data. The measurements of liquid phase composition and bubble point tem-perature are well represented by the Wilson equation. Values of vapor molecular fractions and activity coefficients from the Wilson equation are presented. This work provides important engineering data for the separation of 1,2-dichloroethane and 1,2-epoxycyclohexane .

  1. Synthesis of Ag-Au bimetallic film at liquid-liquid interface and its application in vapor sensing

    Energy Technology Data Exchange (ETDEWEB)

    Pasricha, Renu, E-mail: pasrichar@mail.nplindia.ernet.i [Material Characterization Division, National Physical Laboratory, New Delhi-110012 (India); Gupta, Shweta [Material Characterization Division, National Physical Laboratory, New Delhi-110012 (India); Sastry, M. [Tata Chemical Innovation Center, Anmol Pride, Baner Road, Pune-45 (India); Singh, Nahar; Gupta, Prabhat [Material Characterization Division, National Physical Laboratory, New Delhi-110012 (India)

    2010-11-30

    We demonstrate a novel process for preparing densely packed film of silver nanoparticles at the liquid-liquid interface followed by a transmetallation reaction with gold ion to yield a film of bimetallic nanoparticles. Films of assembled silver as well as Ag-Au bimetallic were characterized by UV-vis-spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. I-V measurement shows linear behavior for both the films with ca. five orders of magnitude drop in resistance for the Ag-Au bimetallic film. Temperature dependent I-V measurement revealed a semiconductor to metal transition after transmetallation reaction. The films where checked for their potential application in chemical vapor sensing to ammonia vapors.

  2. Fragment structure from vapor explosions during the impact of molten metal droplets into a liquid pool

    Science.gov (United States)

    Kouraytem, Nadia; Li, Er Qiang; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur

    2015-11-01

    High-speed video imaging is used in order to look at the impact of a molten metal drop falling into a liquid pool. The interaction regimes are three: film boiling, nucleate boiling or vapor explosion. Following the vapor explosion, the metal fragments and different textures are observed. It was seen that, using a tin alloy, a porous structure results whereas using a distinctive eutectic metal, Field's metal, micro beads are formed. Different parameters such as the metal type, molten metal temperature, pool surface tension and pool boiling temperature have been altered in order to assess the role they play on the explosion dynamics and the molten metal's by product.

  3. Closed-loop phase diagrams, vaporization, and multicriticality in binary liquid mixtures

    Science.gov (United States)

    Caflisch, Robert G.; Walker, James S.

    1983-09-01

    The coupled Potts-Ising models of Walker and Vause, which successfully describe closed-loop phase diagrams in hydrogen-bonding mixtures, are generalized to encompass the vapor phase, and are studied using position-space renormalization-group techniques. Global phase diagrams are generated, exhibiting such features as miscibility-immiscibility criticality, liquid-vapor critical points, critical end points, and bicritical and tricritical points. In addition, new types of phase diagrams are found, involving upper and lower azeotropes, for example, which are expected to be physically realizable in experimental systems.

  4. Methods for calculation of engineering parameters for gas separation. [vapor pressure and solubility of gases in organic liquids

    Science.gov (United States)

    Lawson, D. D.

    1979-01-01

    A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

  5. Mechanism of supercooled droplet freezing on surfaces

    Science.gov (United States)

    Jung, Stefan; Tiwari, Manish K.; Doan, N. Vuong; Poulikakos, Dimos

    2012-01-01

    Understanding ice formation from supercooled water on surfaces is a problem of fundamental importance and general utility. Superhydrophobic surfaces promise to have remarkable 'icephobicity' and low ice adhesion. Here we show that their icephobicity can be rendered ineffective by simple changes in environmental conditions. Through experiments, nucleation theory and heat transfer physics, we establish that humidity and/or the flow of a surrounding gas can fundamentally switch the ice crystallization mechanism, drastically affecting surface icephobicity. Evaporative cooling of the supercooled liquid can engender ice crystallization by homogeneous nucleation at the droplet-free surface as opposed to the expected heterogeneous nucleation at the substrate. The related interplay between droplet roll-off and rapid crystallization is also studied. Overall, we bring a novel perspective to icing and icephobicity, unveiling the strong influence of environmental conditions in addition to the accepted effects of the surface conditions and hydrophobicity.

  6. Testing the recent charge-on-spring type polarizable water models. II. Vapor-liquid equilibrium

    Science.gov (United States)

    Kiss, Péter T.; Baranyai, András

    2012-11-01

    We studied the vapor-liquid coexistence region of seven molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS/G2, COS/G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004), 10.1063/1.1805516], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003), 10.1063/1.1598191], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006), 10.1016/j.cplett.2005.10.135], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012), 10.1063/1.3692602] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011), 10.1063/1.3670962], while the BKd3 model has variable size to approximate the temperature-density (T-ρ) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 194102 (2012), 10.1063/1.4767063]. We calculated the second virial coefficient, the heat of vaporization, equilibrium vapor pressure, the vapor-liquid coexistence curve, and the surface tension in terms of the temperature. We determined and compared the critical temperatures, densities, and pressures of the models. We concluded that the high temperature slope of the (T-ρ) curve accurately predicts the critical temperature. We found that Gaussian charge distributions have clear advantages over the point charges describing the critical region. It is impossible to describe the vapor-liquid coexistence properties consistently with nonpolarizable models, even if their critical temperature is correct.

  7. Testing the recent charge-on-spring type polarizable water models. II. Vapor-liquid equilibrium.

    Science.gov (United States)

    Kiss, Péter T; Baranyai, András

    2012-11-21

    We studied the vapor-liquid coexistence region of seven molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS∕G2, COS∕G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004)], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003)], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006)], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012)] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011)], while the BKd3 model has variable size to approximate the temperature-density (T-ρ) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 194102 (2012)]. We calculated the second virial coefficient, the heat of vaporization, equilibrium vapor pressure, the vapor-liquid coexistence curve, and the surface tension in terms of the temperature. We determined and compared the critical temperatures, densities, and pressures of the models. We concluded that the high temperature slope of the (T-ρ) curve accurately predicts the critical temperature. We found that Gaussian charge distributions have clear advantages over the point charges describing the critical region. It is impossible to describe the vapor-liquid coexistence properties consistently with nonpolarizable models, even if their critical temperature is correct.

  8. Background vapor from six ionic liquids and the partition coefficients and limits of detection for 10 different analytes in those ionic liquids measured using headspace gas chromatography.

    Science.gov (United States)

    Von Wald, Grant; Albers, David; Cortes, Hernan; McCabe, Terry

    2008-08-01

    The concentration and identity of the compounds detected in the vapor above six ionic liquids by headspace gas chromatography (HS-GC) at 100 degrees C are reported. In addition, the partition coefficients for 10 different compounds in these ionic liquids and limits of detection were measured. These results provide quantitative guidance for the application of ionic liquids for HS-GC.

  9. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

    Science.gov (United States)

    Yoshikawa, Masahiro; Koga, Nobuyoshi

    2016-01-01

    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  10. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

    Science.gov (United States)

    Yoshikawa, Masahiro; Koga, Nobuyoshi

    2016-01-01

    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  11. Asymmetric gravity jitter excited slosh waves at a liquid-vapor-solid interface in microgravity

    Science.gov (United States)

    Hung, R. J.; Pan, H. L.; Leslie, F. W.

    1992-01-01

    The dynamical behavior of fluids affected by the asymmetric gravity jitter oscillations is investigated focusing on the surface tension effect on partially filled rotating fluids in a sub-scale gravity probe-B spacecraft propellant dewar tank. Data obtained revealed that the lower frequency gravity jitter imposed on the time-dependent variations of the background gravity direction induced a greater amplitude of oscillations and a stronger degree of asymmetry in liquid-vapor interface geometry than that caused by the higher frequency gravity jitter. It is also found that the greater the components of background gravity in radial and circumferential directions the greater the contribution to driving more toward increasing amplitude and degrees of asymmetry of the liquid-vapor interface profiles, which in turn modify the disturbance of moment of inertia and angular momentum of spacecraft.

  12. Thermal Lattice Boltzmann Simulations for Vapor-Liquid Two-Phase Flows in Two Dimensions

    Science.gov (United States)

    Wei, Yikun; Qian, Yuehong

    2011-11-01

    A lattice Boltzmann model with double distribution functions is developed to simulate thermal vapor-liquid two-phase flows. In this model, the so-called mesoscopic inter-particle pseudo-potential for the single component multi-phase lattice Boltzmann model is used to simulate the fluid dynamics and the internal energy field is simulated by using a energy distribution function. Theoretical results for large-scale dynamics including the internal energy equation can be derived and numerical results for the coexistence curve of vapor-liquid systems are in good agreement with the theoretical predictions. It is shown from numerical simulations that the model has the ability to mimic phase transitions, bubbly flows and slugging flows. This research is support in part by the grant of Education Ministry of China IRT0844 and the grant of Shanghai CST 11XD1402300.

  13. Joule-Thomson Inversion in Vapor-Liquid-Solid Solution Systems

    Science.gov (United States)

    Nichita, Dan Vladimir; Pauly, Jerome; Daridon, Jean-Luc

    2009-07-01

    Solid phase precipitation can greatly affect thermal effects in isenthalpic expansions; wax precipitation may occur in natural hydrocarbon systems in the range of operating conditions, the wax appearance temperature being significantly higher (as high as 350 K) for hyperbaric fluids. Recently, methods for calculating the Joule-Thomson inversion curve (JTIC) for two-phase mixtures, and for three-phase vapor-liquid-multisolid systems have been proposed. In this study, an approach for calculating the JTIC for the vapor-liquid-solid solution systems is presented. The JTIC is located by tracking extrema and angular points of enthalpy departure variations versus pressure at isothermal conditions. The proposed method is applied to several complex synthetic and naturally occurring hydrocarbon systems. The JTIC can exhibit several distinct branches (which may lie within two- or three-phase regions or follow phase boundaries), multiple inversion temperatures at fixed pressure, as well as multiple inversion pressures at given temperature.

  14. Vapor-liquid phase equilibria of water modelled by a Kim-Gordon potential

    Energy Technology Data Exchange (ETDEWEB)

    Maerzke, K A; McGrath, M J; Kuo, I W; Tabacchi, G; Siepmann, J I; Mundy, C J

    2009-03-16

    Gibbs ensemble Monte Carlo simulations were carried out to investigate the properties of a frozen-electron-density (or Kim-Gordon, KG) model of water along the vapor-liquid coexistence curve. Because of its theoretical basis, such a KG model provides for seamless coupling to Kohn-Sham density functional theory for use in mixed quantum mechanics/molecular mechanics (QM/MM) implementations. The Gibbs ensemble simulations indicate rather limited transferability of such a simple KG model to other state points. Specifically, a KG model that was parameterized by Barker and Sprik to the properties of liquid water at 300 K, yields saturated vapor pressures and a critical temperature that are significantly under- and over-estimated, respectively.

  15. Liquid-Vapor Argon Isotope Fractionation from the Triple Point to the Critical Point

    DEFF Research Database (Denmark)

    Phillips, J. T.; Linderstrøm-Lang, C. U.; Bigeleisen, J.

    1972-01-01

    are compared at the same molar volume. The isotope fractionation factor α for 36Ar∕40Ar between liquid and vapor has been measured from the triple point to the critical temperature. The results are compared with previous vapor pressure data, which cover the range 84–102°K. Although the agreement is within....... The fractionation factor approaches zero at the critical temperature with a nonclassical critical index equal to 0.42±0.02.〈∇2Uc〉/ρc in liquid argon is derived from the experimental fractionation data and calculations of 〈∇2Ug〉/ρg for a number of potential functions for gaseous argon....

  16. Dynamic equilibrium under vibrations of H₂ liquid-vapor interface at various gravity levels.

    Science.gov (United States)

    Gandikota, G; Chatain, D; Lyubimova, T; Beysens, D

    2014-06-01

    Horizontal vibration applied to the support of a simple pendulum can deviate from the equilibrium position of the pendulum to a nonvertical position. A similar phenomenon is expected when a liquid-vapor interface is subjected to strong horizontal vibration. Beyond a threshold value of vibrational velocity the interface should attain an equilibrium position at an angle to the initial horizontal position. In the present paper experimental investigation of this phenomenon is carried out in a magnetic levitation device to study the effect of the vibration parameters, gravity acceleration, and the liquid-vapor density on the interface position. The results compare well with the theoretical expression derived by Wolf [G. H. Wolf, Z. Phys. B 227, 291 (1969)].

  17. Prediction of vapor-liquid equilibriafor hydrocarbon binary systems by regular solution model

    OpenAIRE

    下山, 裕介; 米澤, 節子; 小渕, 茂寿; 福地, 賢治; 荒井, 康彦; Shimoyama, Yusuke; Yonezawa, Setsuko; Kobuchi, Shigetoshi; Fukuchi, Kenii; Arai, Yasuhiko

    2007-01-01

    Vapor-liquid equilibria (VLE) of hydrocarbon binary systems : hexane + benzene (25 °C), toluene + octane (60°C) and cyclohexane + toluene (50°C) were predicted by using a regular solution model. In the present model, the mixing entropy term (Flory-Huggins equation) is included and an interaction parameter between unlike molecules is introduced. Solubility parameters and molar volumes at each temperature required in calculation are estimated by previously proposed methods. VLE of hexane + benz...

  18. Critical-point analysis of the liquid-vapor interfacial surface tension

    Science.gov (United States)

    Salvino, R. E.

    1990-01-01

    The interfacial surface tension of the liquid-vapor system is analyzed near the critical point in a manner similar to bulk thermodynamic critical-point analyses. This is accomplished by a critical-point analysis of the single-phase hard-wall surface tension. Both a Landau expansion and a scaling theory equation of state are investigated. Some general exponent relations are derived and, in addition, some thermodynamically defined correlation lengths are discussed.

  19. Study of the liquid vapor equilibrium in the bromine-hydrobromic acid-water system

    Science.gov (United States)

    Benizri, R.; Lessart, P.; Courvoisier, P.

    1984-01-01

    A glass ebullioscope was built and at atmospheric pressure, liquid-vapor equilibria relative to the Br2-HBr-H2O system, in the concentration range of interest for evaluation of the Mark 13 cycle was studied. Measurements were performed for the brome-azeotrope (HBr-H2O) pseudo-binary system and for the ternary system at temperatures lower than 125 C and in the bromine concentration range up to 13% wt.

  20. High flux diode packaging using passive microscale liquid-vapor phase change

    Energy Technology Data Exchange (ETDEWEB)

    Bandhauer, Todd; Deri, Robert J.; Elmer, John W.; Kotovsky, Jack; Patra, Susant

    2017-09-19

    A laser diode package includes a heat pipe having a fluid chamber enclosed in part by a heat exchange wall for containing a fluid. Wicking channels in the fluid chamber is adapted to wick a liquid phase of the fluid from a condensing section of the heat pipe to an evaporating section of the heat exchanger, and a laser diode is connected to the heat exchange wall at the evaporating section of the heat exchanger so that heat produced by the laser diode is removed isothermally from the evaporating section to the condensing section by a liquid-to-vapor phase change of the fluid.

  1. Correlation for fitting multicomponent vapor-liquid equilibria data and prediction of azeotropic behavior

    Directory of Open Access Journals (Sweden)

    Khalid Farhod Chasib Al-Jiboury

    2007-01-01

    Full Text Available Correlation equations for expressing the boiling temperature as direct function of liquid composition have been tested successfully and applied for predicting azeotropic behavior of multicomponent mixtures and the kind of azeotrope (minimum, maximum and saddle type using modified correlation of Gibbs-Konovalov theorem. Also, the binary and ternary azeotropic point have been detected experimentally using graphical determination on the basis of experimental binary and ternary vapor-liquid equilibrium data.In this study, isobaric vapor-liquid equilibrium for two ternary systems: “1-Propanol – Hexane – Benzene” and its binaries “1-Propanol – Hexane, Hexane – Benzene and 1-Propanol – Benzene” and the other ternary system is “Toluene – Cyclohexane – iso-Octane (2,2,4-Trimethyl-Pentane” and its binaries “Toluene – Cyclohexane, Cyclohexane – iso-Octane and Toluene – iso-Octane” have been measured at 101.325 KPa. The measurements were made in recirculating equilibrium still with circulation of both the vapor and liquid phases. The ternary system “1-Propanol – Hexane – Benzene” which contains polar compound (1-Propanol and the two binary systems “1-Propanol – Hexane and 1-Propanol – Benzene” form a minimum azeotrope, the other ternary system and the other binary systems do not form azeotrope.All the data passed successfully the test for thermodynamic consistency using McDermott-Ellis test method (McDermott and Ellis, 1965.The maximum likelihood principle is developed for the determination of correlations parameters from binary and ternary vapor-liquid experimental data which provides a mathematical and computational guarantee of global optimality in parameters estimation for the case where all the measured variables are subject to errors and the non ideality of both vapor and liquid phases for the experimental data for the ternary and binary systems have been accounted.The agreement between prediction and experimental data is

  2. Transport properties of supercooled confined water

    Science.gov (United States)

    Mallamace, F.; Branca, C.; Broccio, M.; Corsaro, C.; Gonzalez-Segredo, N.; Spooren, J.; Stanley, H. E.; Chen, S.-H.

    2008-07-01

    This article presents an overview of recent experiments performed on transport properties of water in the deeply supercooled region, a temperature region of fundamental importance in the science of water. We report data of nuclear magnetic resonance, quasi-elastic neutron scattering, Fourier-transform infrared spectroscopy, and Raman spectroscopy, studying water confined in nanometer-scale environments. When contained within small pores, water does not crystallise, and can be supercooled well below its homogeneous nucleation temperature Th. On this basis it is possible to carry out a careful analysis of the well known thermodynamical anomalies of water. Studying the temperature and pressure dependencies of water dynamics, we show that the liquid-liquid phase transition (LLPT) hypothesis represents a reliable model for describing liquid water. In this model, water in the liquid state is a mixture of two different local structures, characterised by different densities, namely the low density liquid (LDL) and the high-density liquid (HDL). The LLPT line should terminate at a special transition point: a low-T liquid-liquid critical point. We discuss the following experimental findings on liquid water: (i) a crossover from non-Arrhenius behaviour at high T to Arrhenius behaviour at low T in transport parameters; (ii) a breakdown of the Stokes-Einstein relation; (iii) the existence of a Widom line, which is the locus of points corresponding to maximum correlation length in the p-T phase diagram and which ends in the liquid-liquid critical point; (iv) the direct observation of the LDL phase; (v) a minimum in the density at approximately 70 K below the temperature of the density maximum. In our opinion these results represent the experimental proofs of the validity of the LLPT hypothesis.

  3. Combined Gravity Gradient and Jitter Accelerations Acting on Liquid-Vapor Interface Oscillations in Reduced Gravity

    Science.gov (United States)

    Hung, R. J.; Pan, H. L.

    1995-01-01

    The dynamical behavior of fluids affected by the asymmetric combined gravity gradient and jitter accelerations, in particular the effect of surface tension on partially-filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank, have been investigated. Three different cases of accelerations, one gravity gradient-dominated, one equally weighted between gravity gradient and jitter, and the others gravity jitter-dominated are studied. Results of slosh wave excitation along the liquid-vapor interface induced by gravity gradient-dominated acceleration indicate that the gravity gradient-dominated acceleration is equivalent to the combined effect of a twisting force and torsional moment acting on the spacecraft. Results of the slosh wave excitation along the liquid vapor interface induced by gravity jitter-dominated acceleration indicate that the gravity jitter-dominated acceleration is equivalent to time-dependent oscillatory forces which push the bubble in the combined directions of down-and-up and sideward -and-middleward as the bubble is rotating with respect to rotating dewar axis. This study discloses the slosh wave excitation along the liquid-vapor interface driven by the combined effects of gravity gradient and jitter accelerations which are two major driving forces affecting the stability of the fluid system in microgravity.

  4. 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.

  5. Influence of the Vapor Cavity Depth on Liquid Flow through a Microchannel Exhibiting Superhydrophobic Walls

    Science.gov (United States)

    Maynes, Daniel; Jeffs, Kevin; Woolford, Brady; Webb, Brent

    2007-11-01

    We report results of an analytical and experimental investigation of laminar flow in a parallel-plate microchannel with superhydrophobic walls. The walls are fabricated with hydrophobically coated micro-ribs and cavities that are oriented parallel to the flow direction and are modeled in an idealized fashion, with the shape of the liquid-vapor meniscus approximated as flat. An analytical model of the flow in the vapor cavity is employed and coupled with a numerical model of the liquid flow. The numerical predictions show that the effective slip length and the reduction in the classical friction factor-Reynolds number product increase with increasing relative cavity width and depth, and decreasing relative micro-rib/cavity module length. Comparisons are also made between the zero shear interface model and the liquid-vapor cavity coupled model. The results illustrate that the zero shear interface model under-predicts the overall flow resistance. Further, the deviation between the two models was found to be significantly larger for increasing values of both the relative rib/cavity module width and the cavity fraction. The trends in the frictional pressure drop predictions are in good agreement with experimental measurements made at similar conditions and a generalized expression for predicting the friction factor is proposed.

  6. The processes of vaporization in the porous structures working with the excess of liquid

    Directory of Open Access Journals (Sweden)

    Genbach Alexander A.

    2017-01-01

    Full Text Available The processes of vaporization in porous structures, working with the excess of liquid are investigated. With regard to the thermal power plants new porous cooling system is proposed and investigated, in which the supply of coolant is conducted by the combined action of gravity and capillary forces. The cooling surface is made of stainless steel, brass, copper, bronze, nickel, alundum and glass, with wall thickness of (0.05-2•10-3 m. Visualizations of the processes of vaporization were carried out using holographic interferometry with the laser system and high speed camera. The operating conditions of the experiments were: water pressures (0.01-10 MPa, the temperature difference of sub-cooling (0-20°C, an excess of liquid (1-14 of the steam flow, the heat load (1-60•104 W/m2, the temperature difference (1-60°C and orientation of the system (± 0 - ± 90 degrees. Studies have revealed three areas of liquid vaporization process (transitional, developed and crisis. The impact of operating and design parameters on the integrated and thermal hydraulic characteristics was defined. The optimum (minimum flow rate of cooling fluid and the most effective type of mesh porous structure were also defined.

  7. Vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria calculations for polystyrene plus methyleyclohexane and polystyrene plus cyclohexane solutions

    DEFF Research Database (Denmark)

    Wilczura-Wachnik, H.; Jonsdottir, Svava Osk

    2006-01-01

    This paper presents the vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria predictions for polystyrene in two theta solvents: cyclohexane and methylcyclohexane. VLE calculations were performed with the Elbro free volume method and a modified version of the PC-SAFT method, as well...... as with three UNIFAC type group contribution models: Entropic Free Volume + UNIFAC VLE 1 coeff., Entropic Free Volume + UNIFAC VLE 2coeff., and Oishi-Prausnitz + UNIFAC VLE 2coeff. Solvent activities were calculated for the polystyrene + cyclohexane and polystyrene + methylcyclohcxane solutions, and compared...

  8. Vaporization of the prototypical ionic liquid BMImNTf₂ under equilibrium conditions: a multitechnique study.

    Science.gov (United States)

    Brunetti, Bruno; Ciccioli, Andrea; Gigli, Guido; Lapi, Andrea; Misceo, Nicolaemanuele; Tanzi, Luana; Vecchio Ciprioti, Stefano

    2014-08-07

    The vaporization behaviour and thermodynamics of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf2) were studied by combining the Knudsen Effusion Mass Loss (KEML) and Knudsen Effusion Mass Spectrometry (KEMS) techniques. KEML studies were carried out in a large temperature range (398-567) K by using effusion orifices with 0.3, 1, and 3 mm diameters. The vapor pressures so measured revealed no kinetically hindered vaporization effects and provided second-law vaporization enthalpies at the mean experimental temperatures in close agreement with literature. By exploiting the large temperature range covered, the heat capacity change associated with vaporization was estimated, resulting in a value of -66.8 J K(-1) mol(-1), much lower than that predicted from calorimetric measurements on the liquid phase and theoretical calculations on the gas phase. The conversion of the high temperature vaporization enthalpy to 298 K was discussed and the value Δ(l)(g)H(m)(298 K) = (128.6 ± 1.3) kJ mol(-1) assessed on the basis of data from literature and present work. Vapor pressure data were also processed by the third-law procedure using different estimations for the auxiliary thermal functions, and a Δ(l)(g)H(m)(298 K) consistent with the assessed value was obtained, although the overall agreement is sensitive to the accuracy of heat capacity data. KEMS measurements were carried out in the lower temperature range (393-467) K and showed that the largely prevailing ion species is BMIm(+), supporting the common view of BMImNTf2 vaporizing as individual, neutral ion pairs also under equilibrium conditions. By monitoring the mass spectrometric signal of this ion as a function of temperature, a second-law Δ(l)(g)H(m)(298 K) of 129.4 ± 7.3 kJ mol(-1) was obtained, well consistent with KEML and literature results. Finally, by combining KEML and KEMS measurements, the electron impact ionization cross section of BMIm(+) was estimated.

  9. FTS Measurements of Submillimeter-Wave Atmospheric Opacity at Pampa la Bola: III. Water Vapor, Liquid Water, and 183GHz Water Vapor Line Opacities

    Science.gov (United States)

    Matsushita, Satoki; Matsuo, Hiroshi

    2003-02-01

    Further analysis has been made on the millimeter- and submillimeter-wave (100-1600GHz or 3mm-188 μm) atmospheric opacity data taken with the Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above the sea level in northern Chile, which is the site of the Atacama Large Millimeter/submillimeter Array (ALMA). Time-sequence plots of millimeter- and submillimeter-wave opacities show similar variations to each other, except for during the periods with liquid water (fog or clouds) in the atmosphere. Using millimeter- and submillimeter-wave opacity correlations under two conditions, which are affected and not affected by liquid water, we succeeded to separate the measured opacity into water vapor and liquid water opacity components. The water vapor opacity shows a good correlation with the 183GHz water vapor line opacity, which is also covered in the measured spectra. On the other hand, the liquid water opacity and the 183GHz line opacity show no correlation. S ince only the water vapor component is expected to affect the phase of interferometers significantly, and the submillimeter-wave opacity is less affected by the liquid water component, it may be possible to use the submillimeter-wave opacity for a phase correction of submillimeter interferometers.

  10. Utilization of the second gradient theory in continuum mechanics to study motions and thermodynamics of liquid-vapor interfaces

    CERN Document Server

    Gouin, Henri

    2011-01-01

    A thermomechanical model of continuous fluid media based on second gradient theory is used to study motions in liquid-vapor interfaces. At equilibrium, the model is shown to be equivalent to mean-field molecular theories of capillarity. In such fluids, conservative motions verify first integrals that lead to Kelvin circulation theorems and potential equations. The dynamical surface tension of liquid-vapor interfaces is deduced from viscous fluid equations. The result provides and explains the Marangoni effect.

  11. Effect of surface tension, viscosity, and process conditions on polymer morphology deposited at the liquid-vapor interface.

    Science.gov (United States)

    Haller, Patrick D; Bradley, Laura C; Gupta, Malancha

    2013-09-17

    We have observed that the vapor-phase deposition of polymers onto liquid substrates can result in the formation of polymer films or particles at the liquid-vapor interface. In this study, we demonstrate the relationship between the polymer morphology at the liquid-vapor interface and the surface tension interaction between the liquid and polymer, the liquid viscosity, the deposition rate, and the deposition time. We show that the thermodynamically stable morphology is determined by the surface tension interaction between the liquid and the polymer. Stable polymer films form when it is energetically favorable for the polymer to spread over the surface of the liquid, whereas polymer particles form when it is energetically favorable for the polymer to aggregate. For systems that do not strongly favor spreading or aggregation, we observe that the initial morphology depends on the deposition rate. Particles form at low deposition rates, whereas unstable films form at high deposition rates. We also observe a transition from particle formation to unstable film formation when we increase the viscosity of the liquid or increase the deposition time. Our results provide a fundamental understanding about polymer growth at the liquid-vapor interface and can offer insight into the growth of other materials on liquid surfaces. The ability to systematically tune morphology can enable the production of particles for applications in photonics, electronics, and drug delivery and films for applications in sensing and separations.

  12. Supported ionic liquid membranes for removal of dioxins from high-temperature vapor streams.

    Science.gov (United States)

    Kulkarni, Prashant S; Neves, Luisa A; Coelhoso, Isabel M; Afonso, Carlos A M; Crespo, João G

    2012-01-03

    Dioxins and dioxin-like chemicals are predominantly produced by thermal processes such as incineration and combustion at concentrations in the range of 10-100 ng of I-TEQ/kg (I-TEQ = international toxic equivalents). In this work, a new approach for the removal of dioxins from high-temperature vapor streams using facilitated supported ionic liquid membranes (SILMs) is proposed. The use of ceramic membranes containing specific ionic liquids, with extremely low volatility, for dioxin removal from incineration sources is proposed owing to their stability at very high temperatures. Supported liquid membranes were prepared by successfully immobilizing the ionic liquids tri-C(8)-C(10)-alkylmethylammonium dicyanamide ([Aliquat][DCA]) and 1-n-octyl-3-methylimidazolium dicyanamide ([Omim][DCA]) inside the porous structure of ceramic membranes. The porous inorganic membranes tested were made of titanium oxide (TiO(2)), with a nominal pore size of 30 nm, and aluminum oxide (Al(2)O(3)), with a nominal pore size of 100 nm. The ionic liquids were characterized, and the membrane performance was assessed for the removal of dioxins. Different materials (membrane pore size, type of ionic liquid, and dioxin) and different operating conditions (temperature and flow rate) were tested to evaluate the efficiency of SILMs for dioxin removal. All membranes prepared were stable at temperatures up to 200 °C. Experiments with model incineration gas were also carried out, and the results obtained validate the potential of using ceramic membranes with immobilized ionic liquids for the removal of dioxins from high-temperature vapor sources.

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

    Directory of Open Access Journals (Sweden)

    A. C. D. Freitas

    2013-03-01

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

  14. Interfacial stability and self-similar rupture of evaporating liquid layers under vapor recoil

    Science.gov (United States)

    Wei, Tao; Duan, Fei

    2016-12-01

    We investigate interfacial stability of an evaporating viscous liquid layer above/below a horizontal heated substrate in the framework of a long-wave model that accounts for surface tension, positive/negative gravity, and evaporation effects of mass loss and vapor recoil. With the time-dependent linear stability analysis, it is found that the interface instability is enhanced by vapor recoil with time using an effective growth rate. The destabilizing mechanism of vapor thrust competes with the stabilizing surface tension, and the effects of the latter are not asymptotically negligible near rupture, reflected by a rescaled effective interfacial pressure. A two-dimensional nonlinear evolution is investigated for the quasi-equilibrium evaporating layers with different evaporative conditions for Rayleigh-Taylor unstable and sessile layers. For weak mass loss and strong vapor recoil, the well-defined capillary ridges emerge around a deepening narrow valley with increasing wavelength under a positive gravity, while, on the basis of initial condition, main and secondary droplets are either coalesced partially or separated by a sharp dry-out point under a negative gravity. The rupture location depends strongly on the characteristics of a given initial condition, except for the random perturbation. For both the cases, an increase in the modified evaporation number tends to reduce the rupture time tr and droplet thickness remarkably. Similarity analysis along with numerical strategy is presented for the final stage of touch-down dynamics, determined by a physical balance between the vapor recoil and capillary force. The evaporation-driven rupture with a significant vapor recoil and negligible mass loss is shown to contain a countably infinite number of similarity solutions whose horizontal and vertical length scales behave as (tr - t)1/2 and (tr - t)1/3. The first similarity solution represents a stable single-point rupture.

  15. Molecular dynamics of phenol at the liquid-vapor interface of water

    Science.gov (United States)

    Pohorille, Andrew; Benjamin, Ilan

    1991-01-01

    Results of molecular dynamics calculations on phenol at the water liquid-vapor interface are presented. The density profile of the center of mass of phenol exhibits a maximum 1 A from the Gibbs surface toward the vapor phase, indicating that the molecule is surface-active. Changes in the profile caused by the interface extend 6 A from the Gibbs surface into the liquid, significantly more than change in the density profile of water. The most probable orientation of the solute at the surface is such that its symmetry axis is perpendicular to the interface with the OH substituent pointing toward the liquid. An additional simulation with benzene shows that this molecule at the surface most often adopts orientations parallel to the interface. Deeper in the liquid all the solutes are preferentially ordered perpendicular to the surface. In the interfacial region the orientational preferences of the solute are primarily determined by cavity formation needed to accommodate the hydrophobic portion of the dissolved molecule.

  16. Mean-Field Approximation to the Hydrophobic Hydration in the Liquid-Vapor Interface of Water.

    Science.gov (United States)

    Abe, Kiharu; Sumi, Tomonari; Koga, Kenichiro

    2016-03-03

    A mean-field approximation to the solvation of nonpolar solutes in the liquid-vapor interface of aqueous solutions is proposed. It is first remarked with a numerical illustration that the solvation of a methane-like solute in bulk liquid water is accurately described by the mean-field theory of liquids, the main idea of which is that the probability (Pcav) of finding a cavity in the solvent that can accommodate the solute molecule and the attractive interaction energy (uatt) that the solute would feel if it is inserted in such a cavity are both functions of the solvent density alone. It is then assumed that the basic idea is still valid in the liquid-vapor interface, but Pcav and uatt are separately functions of different coarse-grained local densities, not functions of a common local density. Validity of the assumptions is confirmed for the solvation of the methane-like particle in the interface of model water at temperatures between 253 and 613 K. With the mean-field approximation extended to the inhomogeneous system the local solubility profiles across the interface at various temperatures are calculated from Pcav and uatt obtained at a single temperature. The predicted profiles are in excellent agreement with those obtained by the direct calculation of the excess chemical potential over an interfacial region where the solvent local density varies most rapidly.

  17. Stability Limit of Water by Metastable Vapor-Liquid Equilibrium with Nanoporous Silicon Membranes.

    Science.gov (United States)

    Chen, I-Tzu; Sessoms, David A; Sherman, Zachary; Choi, Eugene; Vincent, Olivier; Stroock, Abraham D

    2016-06-16

    Liquid can sustain mechanical tension as its pressure drops below the vapor-liquid coexistence line and becomes less than zero, until it reaches the stability limit-the pressure at which cavitation inevitably occurs. For liquid water, its stability limit is still a subject of debate: the results obtained by researchers using a variety of techniques show discrepancies between the values of the stability limit and its temperature dependence as temperature approaches 0 °C. In this work, we present a study of the stability limit of water by the metastable vapor-liquid equilibrium (MVLE) method with nanoporous silicon membranes. We also report on an experimental system which enables tests of the temperature dependence of the stability limit with MVLE. The stability limit we found increases monotonically (larger tension) as temperature approaches 0 °C; this trend contradicts the centrifugal result of Briggs but agrees with the experiments by acoustic cavitation. This result confirms that a quasi-static method can reach stability values similar to that from the dynamic stretching technique, even close to 0 °C. Nevertheless, our results fall in the range of ∼ -20 to -30 MPa, a range that is consistent with the majority of experiments but is far less negative than the limit obtained in experiments involving quartz inclusions and that predicted for homogeneous nucleation.

  18. Molecular dynamics of phenol at the liquid-vapor interface of water

    Science.gov (United States)

    Pohorille, Andrew; Benjamin, Ilan

    1991-01-01

    Results of molecular dynamics calculations on phenol at the water liquid-vapor interface are presented. The density profile of the center of mass of phenol exhibits a maximum 1 A from the Gibbs surface toward the vapor phase, indicating that the molecule is surface-active. Changes in the profile caused by the interface extend 6 A from the Gibbs surface into the liquid, significantly more than change in the density profile of water. The most probable orientation of the solute at the surface is such that its symmetry axis is perpendicular to the interface with the OH substituent pointing toward the liquid. An additional simulation with benzene shows that this molecule at the surface most often adopts orientations parallel to the interface. Deeper in the liquid all the solutes are preferentially ordered perpendicular to the surface. In the interfacial region the orientational preferences of the solute are primarily determined by cavity formation needed to accommodate the hydrophobic portion of the dissolved molecule.

  19. Low-temperature, vapor-liquid-solid, laterally grown silicon films using alloyed catalysts

    Science.gov (United States)

    LeBoeuf, Jerome L.; Brodusch, Nicolas; Gauvin, Raynald; Quitoriano, Nathaniel J.

    2014-12-01

    Using amorphous oxide templates known as micro-crucibles which confine a vapor-liquid-solid catalyst to a specific geometry, two-dimensional silicon thin-films of a single orientation have been grown laterally over an amorphous substrate and defects within crystals have been necked out. The vapor-liquid-solid catalysts consisted nominally of 99% gold with 1% titanium, chromium, or aluminum, and each alloy affected the processing of micro-crucibles and growth within them significantly. It was found that chromium additions inhibited the catalytic effect of the gold catalysts, titanium changed the morphology of the catalyst during processing and aluminum stabilized a potential third phase in the gold-silicon system upon cooling. Two mechanisms for growing undesired nanowires were identified both of which hindered the VLS film growth, fast silane cracking rates and poor gold etching, which left gold nanoparticles near the gold-vapor interface. To reduce the silane cracking rates, growth was done at a lower temperature while an engineered heat and deposition profile helped to reduce NWs caused by the second mechanism. Through experimenting with catalyst compositions, the fundamental mechanisms which produce concentration gradients across the gold-silicon alloy within a given micro-crucible have been proposed. Using the postulated mechanisms, micro-crucibles were designed which promote high-quality, single crystal growth of semiconductors.

  20. Transient-pressure analysis in geothermal steam reservoirs with an immobile vaporizing liquid phase

    Science.gov (United States)

    Moench, A.F.; Atkinson, P.G.

    1978-01-01

    A finite-difference model for the radial horizontal flow of steam through a porous medium is used to evaluate transient-pressure behavior in the presence of an immobile vaporizing or condensing liquid phase. Graphs of pressure drawdown and buildup in terms of dimensionless pressure and time are obtained for a well discharging steam at a constant mass flow rate for a specified time. The assumptions are made that the steam is in local thermal equilibrium with the reservoir rocks, that temperature changes are due only to phase change, and that effects of vapor-pressure lowering are negligible. Computations show that when a vaporizing liquid phase is present the pressure drawdown exhibits behavior similar to that observed in noncondensable gas reservoirs, but delayed in time. A theoretical analysis allows for the computation of this delay and demonstrates that it is independent of flow geometry. The response that occurs upon pressure buildup is markedly different from that in a noncondensable gas system. This result may provide a diagnostic tool for establishing the existence of phase-change phenomena within a reservoir. ?? 1979.

  1. Toward a Monte Carlo program for simulating vapor-liquid phase equilibria from first principles

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, M; Siepmann, J I; Kuo, I W; Mundy, C J; Vandevondele, J; Sprik, M; Hutter, J; Mohamed, F; Krack, M; Parrinello, M

    2004-10-20

    Efficient Monte Carlo algorithms are combined with the Quickstep energy routines of CP2K to develop a program that allows for Monte Carlo simulations in the canonical, isobaric-isothermal, and Gibbs ensembles using a first principles description of the physical system. Configurational-bias Monte Carlo techniques and pre-biasing using an inexpensive approximate potential are employed to increase the sampling efficiency and to reduce the frequency of expensive ab initio energy evaluations. The new Monte Carlo program has been validated through extensive comparison with molecular dynamics simulations using the programs CPMD and CP2K. Preliminary results for the vapor-liquid coexistence properties (T = 473 K) of water using the Becke-Lee-Yang-Parr exchange and correlation energy functionals, a triple-zeta valence basis set augmented with two sets of d-type or p-type polarization functions, and Goedecker-Teter-Hutter pseudopotentials are presented. The preliminary results indicate that this description of water leads to an underestimation of the saturated liquid density and heat of vaporization and, correspondingly, an overestimation of the saturated vapor pressure.

  2. Thermodynamics and kinetics of vapor bubbles nucleation in one-component liquids.

    Science.gov (United States)

    Alekseechkin, Nikolay V

    2012-08-09

    The multivariable theory of nucleation (J. Chem. Phys. 2006, 124, 124512) is applied to the problem of vapor bubbles formation in pure liquids. The presented self-consistent macroscopic theory of this process employs thermodynamics (classical, statistical, and linear nonequilibrium), hydrodynamics, and interfacial kinetics. As a result of thermodynamic study of the problem, the work of formation of a bubble is obtained and parameters of the critical bubble are determined. The variables V (the bubble volume), ρ (the vapor density), and T (the vapor temperature) are shown to be natural for the given task. An equation for the dependence of surface tension on bubble state parameters is obtained. An algorithm of writing the equations of motion of a bubble in the space {V, ρ, T}--equations for V, ρ, and T--is offered. This algorithm ensures symmetry of the matrix of kinetic coefficients. The equation for T written on the basis of this algorithm is shown to represent the first law of thermodynamics for a bubble. The negative eigenvalue of the motion equations which alongside with the work of the critical bubble formation determines the stationary nucleation rate of bubbles is obtained. Various kinetic limits are considered. One of the kinetic constraints leads to the fact that the nucleation cannot occur in the whole metastable region; it occurs only in some subregion of the latter. Zeldovich's theory of cavitation is shown to be a limiting case of the theory presented. The limiting effects of various kinetic processes on the nucleation rate of bubbles are shown analytically. These are the inertial motion of a liquid as well as the processes of particles exchange and heat exchange between a bubble and surrounding liquid. The nucleation rate is shown to be determined by the slowest kinetic process at positive and moderately negative pressures in a liquid. The limiting effects of the processes of evaporation-condensation and heat exchange vanish at high negative

  3. Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO{sub 2} + alkanol) binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, Arturo; Gutierrez, Jorge E. [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Araus, Karina A. [Departamento de Ingenieria Quimica y Bioprocesos, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Macul, Santiago (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)

    2011-05-15

    Research highlights: (Vapor + liquid) equilibria of three (CO{sub 2} + C{sub 5} alcohol) binary systems were measured. Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. No liquid immiscibility was observed at the temperatures and pressures studied. Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. Correlation results showed relative deviations {<=}8 % (liquid) and {<=}2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO{sub 2} + 3-methyl-2-butanol), (CO{sub 2} + 2-pentanol), and (CO{sub 2} + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO{sub 2} + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

  4. Temporal changes in endmember abundances, liquid water and water vapor over vegetation at Jasper Ridge

    Science.gov (United States)

    Roberts, Dar A.; Green, Robert O.; Sabol, Donald E.; Adams, John B.

    1993-01-01

    Imaging spectrometry offers a new way of deriving ecological information about vegetation communities from remote sensing. Applications include derivation of canopy chemistry, measurement of column atmospheric water vapor and liquid water, improved detectability of materials, more accurate estimation of green vegetation cover and discrimination of spectrally distinct green leaf, non-photosynthetic vegetation (NPV: litter, wood, bark, etc.) and shade spectra associated with different vegetation communities. Much of our emphasis has been on interpreting Airborne Visible/Infrared Imaging Spectrometry (AVIRIS) data spectral mixtures. Two approaches have been used, simple models, where the data are treated as a mixture of 3 to 4 laboratory/field measured spectra, known as reference endmembers (EM's), applied uniformly to the whole image, to more complex models where both the number of EM's and the types of EM's vary on a per-pixel basis. Where simple models are applied, materials, such as NPV, which are spectrally similar to soils, can be discriminated on the basis of residual spectra. One key aspect is that the data are calibrated to reflectance and modeled as mixtures of reference EM's, permitting temporal comparison of EM fractions, independent of scene location or data type. In previous studies the calibration was performed using a modified-empirical line calibration, assuming a uniform atmosphere across the scene. In this study, a Modtran-based calibration approach was used to map liquid water and atmospheric water vapor and retrieve surface reflectance from three AVIRIS scenes acquired in 1992 over the Jasper Ridge Biological Preserve. The data were acquired on June 2nd, September 4th and October 6th. Reflectance images were analyzed as spectral mixtures of reference EM's using a simple 4 EM model. Atmospheric water vapor derived from Modtran was compared to elevation, and community type. Liquid water was compare to the abundance of NPV, Shade and Green Vegetation

  5. Vaporization behavior of tetraoctylphosphonium bis(2-ethylhexyl)phosphate ionic liquid

    Science.gov (United States)

    McMurray, J. W.; Zhou, Y.; Luo, H. M.; Qu, J.

    2017-01-01

    The equilibrium vapor pressures, pe, of the ionic liquid tetraoctylphosphonium bis(2-ethylhexyl)phosphate ([P8888][DEHP]) over the temperature range 409-495 K were determined for the first time using mass loss Knudsen effusion. The pe versus temperature relationship compares well to 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide ([C8mim][NTf2]) but is lower than that of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) when measured using the same technique. The discrepancies between the pe determined in this work for [C8mim][NTf2] and [C2mim][NTf2] with previous studies is discussed. The enthalpy and entropy of vaporization for all three fluids are estimated from the Clasius-Clapeyron relation.

  6. Liquid-Desiccant Vapor Separation Reduces the Energy Requirements of Atmospheric Moisture Harvesting.

    Science.gov (United States)

    Gido, Ben; Friedler, Eran; Broday, David M

    2016-08-02

    An innovative atmospheric moisture harvesting system is proposed, where water vapor is separated from the air prior to cooling and condensation. The system was studied using a model that simulates its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations are reported for different operation conditions. Model results were compared to specifications of commercial atmospheric moisture harvesting systems and found to represent saving of 5-65% of the electrical energy requirements due to the vapor separation process. We show that the liquid desiccant separation stage that is integrated into atmospheric moisture harvesting systems can work under a wide range of environmental conditions using low grade or solar heating as a supplementary energy source, and that the performance of the combined system is superior.

  7. Effect of sintering columns on the heat transfer and flow characteristics of the liquid cooling vapor chambers

    Science.gov (United States)

    Naphon, Paisarn; Wiriyasart, Songkran

    2016-09-01

    The results of the heat and flow characteristics of working fluid inside the vapor chamber with different sintering columns of 20, 81, 225 are presented. The vapor chambers with one inlet port and four outlet ports are tested by using water as coolant. Parametric studies including different heat fluxes, number and size of wick columns, and flow rate of coolants on the cooling performance are considered. A three-dimensional heat and mass transfer model for vapor chamber with wick and without sintering plate and sintering columns are developed. The numerical simulation results show the velocity and pressure distribution of liquid and vapor phases of the working fluid inside the vapor chamber. It is found that the number of wick column have an important influence to the velocity and pressure phenomena of working fluid which results in thermal performance of vapor chamber. Reasonable agreement is obtained from the comparison between the measured data and the predicted results.

  8. Supercooled smectic nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Koch, Michel H J; Fahr, Alfred

    2009-01-01

    , laser diffraction combined with polarizing intensity differential scattering, DSC and SAXS. The morphology of selected formulations was studied by freeze-fracture electron microscopy. All smectic nanoparticles with a mixed cholesterol ester matrix were stable against recrystallization when stored...... in the bulk was studied by polarizing light microscopy, differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS). Colloidal dispersions with pure and mixed cholesterol ester matrices were prepared by high-pressure melt homogenization and characterized by photon correlation spectroscopy...... administration of lipophilic drugs, the cytotoxicity of selected formulations was compared with that of a clinically used colloidal fat emulsion (Lipofundin MCT) in the murine fibroblast cell line L929 using the sulforhodamine B assay. The supercooled smectic nanoparticle formulations display a good overall cell...

  9. Distribution of binding energies of a water molecule in the water liquid-vapor interface

    Energy Technology Data Exchange (ETDEWEB)

    Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV

    2008-01-01

    Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

  10. Modeling p VT Properties and Vapor-Liquid Equilibrium of Ionic Liquids Using Cubic-plus-association Equation of State

    Institute of Scientific and Technical Information of China (English)

    马俊; 李进龙; 范冬福; 彭昌军; 刘洪来; 胡英

    2011-01-01

    Combining Peng-Robinson (PR) equation of state (EoS) with an association model derived from shield-sticky method (SSM) by Liu et al., a new cubic-plus-association (CPA) EoS is proposed to describe the ther-modynamic properties of pure ionic liquids (ILs) and their mixtures. The new molecular parameters for 25 ILs are obtained by fitting the experimental density data over a wide temperature and pressure range, and the overall aver-age deviation is 0.22%. The model parameter b for homologous ILs shows a good linear relationship with their mo-lecular mass, so the number of model parameters is reduced effectively. Using one temperature-independent binary adjustable parameter kij, satisfactory correlations of vapor-liquid equilibria (VLE) for binary mixtures of ILs + non-associating solvents and + associating solvents are obtained with the overall average deviation of vapor pressure 2.91% and 7.01%, respectively. In addition, VLE results for ILs + non-associating mixtures from CPA, lattice-fluid (LF) and square-well chain fluids with variable range (SWCF-VR) EoSs are compared.

  11. Capillary stability of vapor-liquid-solid crystallization processes and their comparison to Czochralski and Stepanov growth methods

    Science.gov (United States)

    Nebol'sin, Valery A.; Suyatin, Dmitry B.; Dunaev, Alexander I.; Tatarenkov, Alexander F.

    2017-04-01

    Epitaxial semiconductor nanowires grown with vapor-liquid-solid crystallization processes are very attractive nanoscale objects for many different applications. Despite extensive studies of the growth mechanism, there is still a lack of understanding of the growth process; in particular, the stability of the vapor-liquid-solid crystallization process has not previously been studied. Here we examine the capillary stability of the vapor-liquid-solid growth of nanowires and filamentary crystals with different diameters and demonstrate that the growth is stable for small Bond numbers when the meniscus height is linearly dependent on catalyst diameter. The capillary stability of vapor-liquid-solid growth is also compared with capillary stability in the Stepanov and Czochralski crystal growth methods; it is shown that capillary stability is not possible in the Czochralski method, although it is possible in the Stepanov growth method when the ratio of crystal diameter to shaper diameter is >1/2. These findings are important for better understanding and improved control of the growth of nanowires and filamentary crystals and indicate, for example, that large diameter filamentary crystals can be grown via a vapor-liquid-solid mechanism if the influence of gravity forces on the liquid catalytic particle shape can be reduced.

  12. Understanding the influence of capillary waves on solvation at the liquid-vapor interface.

    Science.gov (United States)

    Rane, Kaustubh; van der Vegt, Nico F A

    2016-03-21

    This work investigates the question if surface capillary waves (CWs) affect interfacial solvation thermodynamic properties that determine the propensity of small molecules toward the liquid-vapor interface. We focus on (1) the evaluation of these properties from molecular simulations in a practical manner and (2) understanding them from the perspective of theories in solvation thermodynamics, especially solvent reorganization effects. Concerning the former objective, we propose a computational method that exploits the relationship between an external field acting on the liquid-vapor interface and the magnitude of CWs. The system considered contains the solvent, an externally applied field (f) and the solute molecule fixed at a particular location. The magnitude of f is selected to induce changes in CWs. The difference between the solvation free energies computed in the presence and in the absence of f is then shown to quantify the contribution of CWs to interfacial solvation. We describe the implementation of this method in the canonical ensemble by using a Lennard-Jones solvent and a non-ionic solute. Results are shown for three types of solutes that differ in the nature of short-ranged repulsive (hard-core) interactions. Overall, we observe that CWs have a negligible or very small effect on the interfacial solvation free energy of a solute molecule fixed near the liquid-vapor interface for the above systems. We also explain how the effects of pinning or dampening of CWs caused by a fixed solute are effectively compensated and do not contribute to the solvation free energy.

  13. New Isotopic Water Analyzer for Hydrological Measurements of Both Liquid Water and Water Vapor

    Science.gov (United States)

    Owano, T.; Gupta, M.; Berman, E.; Baer, D.

    2012-04-01

    Measurements of the stable isotope ratios of liquid water allow determination of water flowpaths, residence times in catchments, and groundwater migration. Previously, discrete water samples have been collected and transported to an IRMS lab for isotope characterization. Due to the expense and labor associated with such sampling, isotope studies have thus been generally limited in scope and in temporal resolution. We report on the recent development of the first Isotopic Water Analyzer that simultaneously quantifies δ2H, δ17O and δ18O in liquid water or in water vapor from different natural water sources (e.g., rain, snow, streams and groundwater). In High-Throughput mode, the IWA can report measurements at the unprecedented rate of over 800 injections per day, which yields more than 140 total unknown and reference samples per day (still with 6 injections per measurement). This fast time response provides isotope hydrologists with the capability to study dynamic changes in δ values quickly (minutes) and over long time scales (weeks, months), thus enabling studies of mixing dynamics in snowmelt, canopy throughfall, stream mixing, and allows for individual precipitation events to be independently studied. In addition, the same IWA can also record fast measurements of isotopic water vapor (δ2H, δ17O, δ18O) in real time (2 Hz data rate or faster) over a range of mole fractions greater than 60000 ppm H2O in air. Changing between operational modes requires a software command, to enable the user to switch from measuring liquid water to measuring water vapor, or vice versa. The new IWA, which uses LGR's patented Off-axis ICOS technology, incorporates proprietary internal thermal control for stable measurements with essentially zero drift despite changes in ambient temperature (over the entire range from 0-45 degrees C). Measurements from recent field studies using the IWA will be presented.

  14. Feasibility of refreezing human spermatozoa through the technique of liquid nitrogen vapor

    Directory of Open Access Journals (Sweden)

    Sidney Verza Jr

    2004-12-01

    Full Text Available OBJECTIVE: To assess the feasibility of refreezing human semen using the technique of liquid nitrogen vapor with static phases. MATERIALS AND METHODS: Twenty samples from 16 subjects who required disposal of their cryopreserved semen were thawed, corresponding to 6 cancer patients and 10 participants in the assisted reproduction (AR program. Samples were refrozen using the technique of liquid nitrogen vapor with static phases, identical to the one used for the initial freezing, and thawed again after 72 hours. We assessed the concentration of motile spermatozoa, total and progressive percent motility and spermatic vitality, according to criteria of the World Health Organization (WHO, as well as spermatic morphology according to the strict Kruger criterion, after the first and after the second thawing. RESULTS: We observed a significant decrease in all the parameters evaluated between the first and the second thawing. Median values for the concentration of motile spermatozoa decreased from 2.0x10(6/mL to 0.1x10(6/mL (p < 0.01; total percent motility from 42% to 22.5% (p < 0.01; progressive percent motility from 34% to 9.5% (p < 0.01; vitality from 45% to 20% (p < 0.01; and morphology from 5% to 5% (p = 0.03. There was no significant difference in the spermatic parameters between the cancer and assisted reproduction groups, both after the first and after the second thawing. We observed that in 100% of cases there was retrieval of motile spermatozoa after the second thawing. CONCLUSIONS: Refreezing of human semen by the technique of liquid nitrogen vapor allows the retrieval of viable spermatozoa after thawing.

  15. The molecular structure of the interface between water and a hydrophobic substrate is liquid-vapor like.

    Science.gov (United States)

    Willard, Adam P; Chandler, David

    2014-11-14

    With molecular simulation for water and a tunable hydrophobic substrate, we apply the instantaneous interface construction [A. P. Willard and D. Chandler, "Instantaneous liquid interfaces," J. Phys. Chem. B 114, 1954-1958 (2010)] to examine the similarity between a water-vapor interface and a water-hydrophobic surface interface. We show that attractive interactions between a hydrophobic surface and water affect capillary wave fluctuations of the instantaneous liquid interface, but these attractive interactions have essentially no effect on the intrinsic interface. The intrinsic interface refers to molecular structure in terms of distances from the instantaneous interface. Further, the intrinsic interface of liquid water and a hydrophobic substrate differs little from that of water and its vapor. The same is not true, we show, for an interface between water and a hydrophilic substrate. In that case, strong directional substrate-water interactions disrupt the liquid-vapor-like interfacial hydrogen bonding network.

  16. Modeling vapor-liquid interfaces with the gradient theory in combination with the CPA equation of state

    DEFF Research Database (Denmark)

    Queimada, Antonio; Miqueu, C; Marrucho, IM

    2005-01-01

    With the final purpose of describing the important aqueous + hydrocarbon liquid-liquid interfaces, the gradient theory was combined with the Cubic-Plus-Association equation of state (CPA EOS), taking advantage of the correct representation of interfacial tensions provided by the gradient theory...... and discussed. The good description of equilibrium properties such as vapor pressure and liquid and vapor phase densities is shown in the full range of the vapor-liquid saturation line. For non-associating components, results are compared with those from the Soave-Redlich-Kwong and Peng-Robinson equations...... of state. A correlation for the influence parameter is presented from which surface tensions can be obtained in a broad temperature range with average errors smaller than 1%. (c) 2004 Elsevier B.V. All rights reserved....

  17. Interaction of monovalent ions with the water liquid-vapor interface - A molecular dynamics study

    Science.gov (United States)

    Wilson, Michael A.; Pohorille, Andrew

    1991-01-01

    Results of molecular dynamics calculations are presented for a series of ions at infinite dilution near the water liquid-vapor interface. The free energies of ion transfer from the bulk to the interface are discussed, as are the accompanying changes of water structure at the surface and ion mobilities as a function of their proximity to the interface. It is shown that simple dielectric models do not provide an accurate description of ions at the water surface. The results of the study should be useful in the development of better models incorporating the shape and molecular structure of the interface.

  18. Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

    Science.gov (United States)

    Vakarelski, Ivan U.; Berry, Joseph D.; Chan, Derek Y. C.; Thoroddsen, Sigurdur T.

    2016-09-01

    The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re ˜3 ×1 05 . A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ˜600 to 1 05. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape.

  19. Finite-size scaling study of dynamic critical phenomena in a vapor-liquid transition

    Science.gov (United States)

    Midya, Jiarul; Das, Subir K.

    2017-01-01

    Via a combination of molecular dynamics (MD) simulations and finite-size scaling (FSS) analysis, we study dynamic critical phenomena for the vapor-liquid transition in a three dimensional Lennard-Jones system. The phase behavior of the model has been obtained via the Monte Carlo simulations. The transport properties, viz., the bulk viscosity and the thermal conductivity, are calculated via the Green-Kubo relations, by taking inputs from the MD simulations in the microcanonical ensemble. The critical singularities of these quantities are estimated via the FSS method. The results thus obtained are in nice agreement with the predictions of the dynamic renormalization group and mode-coupling theories.

  20. Thermodynamic Study of the Role of Interface Curvature on Multicomponent Vapor-Liquid Phase Equilibrium.

    Science.gov (United States)

    Shardt, Nadia; Elliott, Janet A W

    2016-04-14

    The effect of interface curvature on phase equilibrium has been much more studied for single-component than multicomponent systems. We isolate the effect of curvature on multicomponent vapor-liquid equilibrium (VLE) phase envelopes and phase composition diagrams using the ideal system methanol/ethanol and the nonideal system ethanol/water as illustrative examples. An important finding is how nanoscale interface curvature shifts the azeotrope (equal volatility point) of nonideal systems. Understanding of the effect of curvature on VLE can be exploited in future nanoscale prediction and design.

  1. Interaction of monovalent ions with the water liquid-vapor interface - A molecular dynamics study

    Science.gov (United States)

    Wilson, Michael A.; Pohorille, Andrew

    1991-01-01

    Results of molecular dynamics calculations are presented for a series of ions at infinite dilution near the water liquid-vapor interface. The free energies of ion transfer from the bulk to the interface are discussed, as are the accompanying changes of water structure at the surface and ion mobilities as a function of their proximity to the interface. It is shown that simple dielectric models do not provide an accurate description of ions at the water surface. The results of the study should be useful in the development of better models incorporating the shape and molecular structure of the interface.

  2. Linear stability analysis of convection in two-layer system with an evaporating vapor-liquid interface

    Institute of Scientific and Technical Information of China (English)

    Rong Liu; Qiusheng Liu

    2006-01-01

    Classical theories have successfully provided an explanation for convection in a liquid layer heated from below without evaporation.However,these theories are inadequate to account for the convective instabilities in an evaporating liquid layer,especially in the case when it is cooled from below.In the present paper,we study the onset of Marangoni convection in a liquid layer being overlain by a vapor layer.A new two-sided model is put forward instead of the one-sided in evaporating liquid thin layers are investigated with a linear instability analysis.We define a new evaporation Biot number,Which is different from that in previous studies and discuss the influences of reference evaporating velocity and evaporation Biot number on the vapor-liquid system.At the end,we explain why the instability occurs even when an evaporating liquid layer is cooled from below.

  3. Vaporization heat transfer of dielectric liquids on enhanced surfaces covered with screen wicks

    Science.gov (United States)

    Gu, C. B.; Chow, L. C.; Pais, M. R.; Baker, K.

    1993-01-01

    Experiments were conducted to investigate the vaporization heat transfer characteristics for the dielectric liquid FC-72 on several wicking surfaces which may be used in flat-plate heat pipes. The wicking materials studied included microstructure enhanced surfaces and coarse surfaces covered with screen meshes. Experimental data for q versus deltaT curves and critical heat fluxes were obtained for the two different operating conditions of a heat pipe, evaporation, and shallow pool boiling. When the liquid level was above the heated surface, the height of the liquid level above the surface was varied from 0 to 10 mm. When the liquid level was below the heated surface, the distance from the liquid level to the edge of the surface was adjusted from 0 to 15 mm. Experimental results revealed that for shallow pool boiling when the heated surface was covered with a wire screen mesh, the heat transfer coefficient increased at lower heat fluxes but the critical heat flux (CHF) decreased for all the surfaces tested. In the case of evaporation, both CHF and the heat transfer coefficient increased as the microstructure surfaces were covered with screen meshes.

  4. Vaporization heat transfer of dielectric liquids on enhanced surfaces covered with screen wicks

    Science.gov (United States)

    Gu, C. B.; Chow, L. C.; Pais, M. R.; Baker, K.

    1993-01-01

    Experiments were conducted to investigate the vaporization heat transfer characteristics for the dielectric liquid FC-72 on several wicking surfaces which may be used in flat-plate heat pipes. The wicking materials studied included microstructure enhanced surfaces and coarse surfaces covered with screen meshes. Experimental data for q versus deltaT curves and critical heat fluxes were obtained for the two different operating conditions of a heat pipe, evaporation, and shallow pool boiling. When the liquid level was above the heated surface, the height of the liquid level above the surface was varied from 0 to 10 mm. When the liquid level was below the heated surface, the distance from the liquid level to the edge of the surface was adjusted from 0 to 15 mm. Experimental results revealed that for shallow pool boiling when the heated surface was covered with a wire screen mesh, the heat transfer coefficient increased at lower heat fluxes but the critical heat flux (CHF) decreased for all the surfaces tested. In the case of evaporation, both CHF and the heat transfer coefficient increased as the microstructure surfaces were covered with screen meshes.

  5. Studies on micro-structures at vapor-liquid interfaces of film boiling on hot liquid surface at arriving of a shock pressure

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akira; Lee, S. [Tokyo Inst. of Tech. (Japan)

    1998-01-01

    In vapor explosions, a pressure wave (shock wave) plays a fundamental role in the generation, propagation and escalation of the explosion. Transient volume change by rapid heat flow from a high temperature liquid to a low temperature volatile one and phase change generate micro-scale flow and the pressure wave. One of key issues for the vapor explosion is to make clear the mechanism to support the explosive energy release from hot drop to cold liquid. According to our observations by an Image Converter Camera, growth rate of vapor film around a hot tin drop became several times higher than that around a hot Platinum tube at the same conditions when a pressure pulse collapsed the film. The thermally induced fragmentation was followed by the explosive growth rate of the hot drop. In the previous report, we have proposed that the interface instability and fragmentation model in which the fine Taylor instability of vapor-liquid interface at the collapsing and re-growth phase of vapor film and the instability induced by the high pressure spots at the drop surface were assumed. In this study, the behavior of the vapor-liquid interface region at arrival of a pressure pulse was investigated by the CIPRIS code which is able to simulate dynamics of transient multi-phase interface regions. It is compared with the observation results. Through detailed investigations of these results, the mechanisms of the thermal fragmentation of single drop are discussed. (J.P.N.)

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  7. Fabrication and performance evaluation of a high temperature co-fired ceramic vaporizing liquid microthruster

    Science.gov (United States)

    How Cheah, Kean; Low, Kay-Soon

    2015-01-01

    This paper presents the study of a microelectromechanical system (MEMS)-scaled microthruster using ceramic as the structural material. A vaporizing liquid microthruster (VLM) has been fabricated using the high temperature co-fired ceramic (HTCC) technology. The developed microthruster consists of five components, i.e. inlet, injector, vaporizing chamber, micronozzle and microheater, all integrated in a chip with a dimension of 30 mm × 26 mm × 8 mm. In the dry test, the newly developed microheater which is deposited on zirconia substrate consumes 21% less electrical power than those deposited on silicon substrate to achieve a temperature of 100 °C. Heating temperature as high as 409.1 °C can be achieved using just 5 W of electrical power. For simplicity and safety, a functional test of the VLM with water as propellant has been conducted in the laboratory. Full vaporization of water propellant feeding at different flow rates has been successfully demonstrated. A maximum thrust of 633.5 µN at 1 µl s-1 propellant consumption rate was measured using a torsional thrust stand.

  8. On the spatial stability of a liquid jet in the presence of vapor cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Ming; Ning, Zhi, E-mail: zhining@bjtu.edu.cn; Lu, Mei; Yan, Kai; Fu, Juan; Sun, Chunhua [College of Mechanical and Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2013-11-15

    A dispersion equation describing the effect of temperature differences on the stability of three-dimensional cylindrical liquid jets in the presence of vapor cavities is presented by the use of linear stability analysis. The mathematical model and its solving method are verified by comparing them with the data in the literature, and then the effect of temperature differences between jet and surrounding gas on the spatial stability of liquid jet is investigated. Some conclusions can be drawn from the results of this investigation: (1) the temperature difference destabilizes the liquid jet when the jet liquid is cooler than the surrounding gas, (2) the smallest atomized droplet without taking into account the effect of temperature differences is significantly larger than that when the effect of temperature differences is taken into account, (3) the effect of temperature differences on the stability of liquid jet has little relationship with azimuthal wave modes, (4) cavitation destabilizes the liquid jet when the value of the bubble volume fraction is not greater than 0.1 (0 ≤ α ≤ 0.1), and the temperature difference can weaken this effect of cavitation on the stability of liquid jet, and (5) cavitation is responsible for generating smaller droplets, the effect of cavitation on the critical wave number with and without taking into account the effect of temperature differences is quite different, and temperature difference is likely to fully restrain the effect of cavitation on the critical wave number; however, cavitation is again responsible for generating smaller droplets despite the effect of temperature differences when the bubble volume fraction α = 0.1. These findings may explain some observations of practical atomizer performance.

  9. A corresponding-states analysis of the liquid-vapor equilibrium properties of common water models

    Science.gov (United States)

    Fugel, Malte; Weiss, Volker C.

    2017-02-01

    Many atomistic potential models have been proposed to reproduce the properties of real water and to capture as many of its anomalies as possible. The large number of different models indicates that this task is by no means an easy one. Some models are reasonably successful for various properties, while others are designed to account for only a very few specific features of water accurately. Among the most popular models are SPC/E, TIP4P, TIP4P/2005, TIP4P/Ice, and TIP5P-E. Here, we report the equilibrium properties of the liquid-vapor coexistence, such as the densities of the liquid phase and the vapor phase, the interfacial tension between them, and the vapor pressure at saturation. From these data, the critical parameters are determined and subsequently used to cast the liquid-vapor coexistence properties into a corresponding-states form following Guggenheim's suggestions. Doing so reveals that the three TIP4P-based models display the same corresponding-states behavior and that the SPC/E model behaves quite similarly. Only the TIP5P-E model shows clear deviations from the corresponding-states properties of the other models. A comparison with data for real water shows that the reduced surface tension is well described, while the reduced coexistence curve is too wide. The models underestimate the critical compressibility factor and overestimate Guggenheim's ratio as well as the reduced boiling temperature (Guldberg's ratio). As demonstrated by the collapse of the data for the TIP4P-based models, these deviations are inherent to the specific model and cannot be corrected by a simple reparametrization. For comparison, the results for two recent polarizable models, HBP and BK3, are shown, and both models are seen to perform well in terms of absolute numbers and in a corresponding-states framework. The kind of analysis applied here can therefore be used as a guideline in the design of more accurate and yet simple multi-purpose models of water.

  10. A corresponding-states analysis of the liquid-vapor equilibrium properties of common water models.

    Science.gov (United States)

    Fugel, Malte; Weiss, Volker C

    2017-02-14

    Many atomistic potential models have been proposed to reproduce the properties of real water and to capture as many of its anomalies as possible. The large number of different models indicates that this task is by no means an easy one. Some models are reasonably successful for various properties, while others are designed to account for only a very few specific features of water accurately. Among the most popular models are SPC/E, TIP4P, TIP4P/2005, TIP4P/Ice, and TIP5P-E. Here, we report the equilibrium properties of the liquid-vapor coexistence, such as the densities of the liquid phase and the vapor phase, the interfacial tension between them, and the vapor pressure at saturation. From these data, the critical parameters are determined and subsequently used to cast the liquid-vapor coexistence properties into a corresponding-states form following Guggenheim's suggestions. Doing so reveals that the three TIP4P-based models display the same corresponding-states behavior and that the SPC/E model behaves quite similarly. Only the TIP5P-E model shows clear deviations from the corresponding-states properties of the other models. A comparison with data for real water shows that the reduced surface tension is well described, while the reduced coexistence curve is too wide. The models underestimate the critical compressibility factor and overestimate Guggenheim's ratio as well as the reduced boiling temperature (Guldberg's ratio). As demonstrated by the collapse of the data for the TIP4P-based models, these deviations are inherent to the specific model and cannot be corrected by a simple reparametrization. For comparison, the results for two recent polarizable models, HBP and BK3, are shown, and both models are seen to perform well in terms of absolute numbers and in a corresponding-states framework. The kind of analysis applied here can therefore be used as a guideline in the design of more accurate and yet simple multi-purpose models of water.

  11. Bubbles in liquids with phase transition. Part 1. On phase change of a single vapor bubble in liquid water

    Science.gov (United States)

    Dreyer, Wolfgang; Duderstadt, Frank; Hantke, Maren; Warnecke, Gerald

    2012-11-01

    In the forthcoming second part of this paper a system of balance laws for a multi-phase mixture with many dispersed bubbles in liquid is derived where phase transition is taken into account. The exchange terms for mass, momentum and energy explicitly depend on evolution laws for total mass, radius and temperature of single bubbles. Therefore in the current paper we consider a single bubble of vapor and inert gas surrounded by the corresponding liquid phase. The creation of bubbles, e.g. by nucleation is not taken into account. We study the behavior of this bubble due to condensation and evaporation at the interface. The aim is to find evolution laws for total mass, radius and temperature of the bubble, which should be as simple as possible but consider all relevant physical effects. Special attention is given to the effects of surface tension and heat production on the bubble dynamics as well as the propagation of acoustic elastic waves by including slight compressibility of the liquid phase. Separately we study the influence of the three phenomena heat conduction, elastic waves and phase transition on the evolution of the bubble. We find ordinary differential equations that describe the bubble dynamics. It turns out that the elastic waves in the liquid are of greatest importance to the dynamics of the bubble radius. The phase transition has a strong influence on the evolution of the temperature, in particular at the interface. Furthermore the phase transition leads to a drastic change of the water content in the bubble. It is shown that a rebounding bubble is only possible, if it contains in addition an inert gas. In Part 2 of the current paper the equations derived are sought in order to close the system of equations for multi-phase mixture balance laws for dispersed bubbles in liquids involving phase change.

  12. High Pressure Vapor-Liquid Equilibrium of Supercritical Carbon Dioxide + n-Hexane System

    Institute of Scientific and Technical Information of China (English)

    YU Jinglin; TIAN Yiling; ZHU Rongjiao; LIU Zhihua

    2006-01-01

    Vapor-liquid equilibrium data of supercritical carbon dioxide + n-hexane system were measured at 313.15 K,333.15 K,353.15 K,and 373.15 K and their molar volumes and densities were measured both in the subcritical and supercritical regions ranging from 2.15 to 12.63 MPa using a variable-volume autoclave.The thermodynamic properties including mole fractions,densities,and molar volumes of the system were calculated with an equation of state by Heilig and Franck,in which a repulsion term and a square-well potential attraction term for intermolecular interaction was used.The pairwise combination rule was used to calculate the square-well molecular interaction potential and three adjustable parameters (ω,kε,kσ) were obtained.The Heilig-Franck equation of state is found to have good correlation with binary vapor-liquid equilibrium data of the carbon dioxide + n-hexane system.

  13. Computer simulation of liquid-vapor coexistence of confined quantum fluids.

    Science.gov (United States)

    Trejos, Víctor M; Gil-Villegas, Alejandro; Martinez, Alejandro

    2013-11-14

    The liquid-vapor coexistence (LV) of bulk and confined quantum fluids has been studied by Monte Carlo computer simulation for particles interacting via a semiclassical effective pair potential Veff(r) = VLJ + VQ, where VLJ is the Lennard-Jones 12-6 potential (LJ) and VQ is the first-order Wigner-Kirkwood (WK-1) quantum potential, that depends on β = 1∕kT and de Boer's quantumness parameter Λ=h/σ√mε, where k and h are the Boltzmann's and Planck's constants, respectively, m is the particle's mass, T is the temperature of the system, and σ and ε are the LJ potential parameters. The non-conformal properties of the system of particles interacting via the effective pair potential Veff(r) are due to Λ, since the LV phase diagram is modified by varying Λ. We found that the WK-1 system gives an accurate description of the LV coexistence for bulk phases of several quantum fluids, obtained by the Gibbs Ensemble Monte Carlo method (GEMC). Confinement effects were introduced using the Canonical Ensemble (NVT) to simulate quantum fluids contained within parallel hard walls separated by a distance Lp, within the range 2σ ≤ Lp ≤ 6σ. The critical temperature of the system is reduced by decreasing Lp and increasing Λ, and the liquid-vapor transition is not longer observed for Lp∕σ < 2, in contrast to what has been observed for the classical system.

  14. High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail: fgarcias@imp.mx; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)

    2007-06-15

    In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

  15. Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K.; Oldenburg, C.; Moridis, G.; Finsterle, S. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport. A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.

  16. Improving prediction of vapor-liquid equilibrium with modified HVOS-PR-UNIFAC model by revision of group interaction parameters

    Institute of Scientific and Technical Information of China (English)

    XUE Rong-shu; LI Yan-jiao; WANG Xiao-qing; TAN Shi-yu; WEI Shun-an

    2007-01-01

    Quantitative description of vapor-liquid equilibrium is very useful for designing separation processes. In this study, we combined the Peng-Robinson equation and the Huron-Vidal-Orbey-Sandler mixing rule into a modified UNIFAC model for the improvement of predicting vapor-liquid equilibria. The predictions of vapor-liquid equilibria for 62 systems including alcoholalkane, alcohol-benzene, and amine-water systems demonstrate that the revised parameters remarkably improve the prediction accuracy for many systems. Especially for amine-water system, the mean deviation of components decreases from 0.094 to 0.021, and the mean deviation of pressure from 22.45% to 4.41%.

  17. Experimental evidence for two distinct deeply supercooled liquid states of water – Response to “Comment on ‘Water's second glass transition”’, by G.P. Johari, Thermochim. Acta (2015)

    Energy Technology Data Exchange (ETDEWEB)

    Stern, J.; Seidl, M. [Institute of Physical Chemistry, University of Innsbruck, 6020 Innsbruck (Austria); Gainaru, C. [Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund (Germany); Fuentes-Landete, V.; Amann-Winkel, K.; Handle, P.H. [Institute of Physical Chemistry, University of Innsbruck, 6020 Innsbruck (Austria); Köster, K.W.; Nelson, H. [Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund (Germany); Böhmer, R., E-mail: roland.bohmer@tu-dortmund.de [Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund (Germany); Loerting, T., E-mail: thomas.loerting@uibk.ac.at [Institute of Physical Chemistry, University of Innsbruck, 6020 Innsbruck (Austria)

    2015-10-10

    Highlights: • Two samples of amorphous ices quench-recovered from 140 K to 0.07 GPa are compared. • Calorimetry, X-ray diffraction, dielectric spectroscopy and volumetry are employed. • The two samples are distinct and cannot both be termed “pressure-densified glassy water”. • One route of preparation leads to high- (HDA), and the other to low-density amorphous ice (LDA). • Two distinct glass transitions are observed and interpreted to indicate two liquid H{sub 2}O phases. - Abstract: Recently, our earlier data which led us to conclude that deeply supercooled water displays a second glass transition (Amann-Winkel et al., 2013) was reinterpreted (Johari, 2015). In particular, the increase in heat capacity observed for high-density amorphous ice (HDA) samples at 116 K was reinterpreted to indicate sub-T{sub g} features of low-density amorphous ice's (LDA's) glass transition. We reply to the criticism in detail and report an experiment triggered by the comment on our work. This experiment unequivocally confirms our original interpretation of the observations and reinforces the case for water's second glass transition, its polyamorphism, and the observation of two distinct ultraviscous states of water differing by about 25% in density.

  18. Performance analysis of OTEC power cycle with a liquid-vapor ejector using R32/R152a

    Science.gov (United States)

    Yoon, Jung-In; Son, Chang-Hyo; Seol, Sung-hoon; Kim, Hyeon-Uk; Ha, Soo-Jung; Jung, Suk-Ho; Kim, Hyeon-Ju; Lee, Ho-Saeng

    2015-11-01

    In this paper, the condensation and evaporation capacity, turbine work, efficiency, and main component size of the Ocean Thermal Energy Conversion (OTEC) power system with a liquid-vapor ejector are presented to offer the basic design data for the operating parameters of the system. The analysis procedure was performed with a simulation program called Aspentech HYSYS. The working fluid used in this system is the R32/R152a mixture. The operating parameters considered in this study include the vapor quality at the reheat outlet, the pressure ratio of the ejector, the inlet pressure of turbine 2, entrainment ratio of the liquid-vapor ejector etc. The main results are summarized as follows. The efficiency of the OTEC power cycle is closely related to the entrainment ratio of the liquid-vapor ejector. Also, the increase rate of the efficiency of proposed OTEC power cycle using the liquid-vapor ejector is 16 % higher than that of basic OTEC power cycle. Furthermore, regarding the reduction ratios of the system size that affects the initial cost, the reduction ratios of the evaporator size and the condenser size are about 13 and 14 % higher than those of basic OTEC power cycle, respectively. And, the pump power and the mass flow rate of the required refrigerant are 8 and 4 %, respectively. Therefore, the proposed OTEC power cycle is more advantageous than basic OTEC power cycle because of the compactness and high-efficiency of the system.

  19. Vapor-liquid equilibrium for the system ethyl alcohol + ester; Equilibrio liquido-vapor para o sistema alcool etilico+ester

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Humberto Neves Maia de; Nascimento, Yuri Corsino do; Chiavone-Filho, Osvaldo [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    This work consists of the experimental determination of a series of vapor-liquid equilibrium (VLE) data, for mixtures of ethyl alcohol + ester (ethyl acetate), prepared synthetically, that may be present in the production of biodiesel. The separation of the ethyl alcohol from esters by distillation is an important stage of this process, and therefore it demands accurate data for an appropriate modelling, and later optimization via simulators. FISCHER'S ebulliometer, with digital control (Model 602), was used for measurement of VLE data for the system ethyl alcohol + ester. It consists of a recirculation cell of the both vapor and liquid phases, providing complete data, i.e., pressure, temperature and compositions of the liquid and vapor phases that were obtained by gaseous chromatography (PTxy). This apparatus is coupled to a thermostatic bath with cooling (TE-184 TECNAL) that aims to condense the coming steams of the ebullition in order to return to the mixture camera. The VLE data obtained experimentally were submitted to the test of thermodynamic consistence of the deviations, where the equation of Gibbs-Duhem is used, through the model UNIQUAC. The parameters obtained from the experimental data can be applied in the simulators of processes with the purpose of optimizing the separation of the ethyl alcohol of Ester. (author)

  20. Liquid-vapor phase equilibria and the thermodynamic properties of 2-methylpropanol- n-alkyl propanoate solutions

    Science.gov (United States)

    Suntsov, Yu. K.; Goryunov, V. A.; Chuikov, A. M.; Meshcheryakov, A. V.

    2016-08-01

    The boiling points of solutions of five binary systems are measured via ebulliometry in the pressure range of 2.05-103.3 kPa. Equilibrium vapor phase compositions, the values of the excess Gibbs energies, enthalpies, and entropies of solution of these systems are calculated. Patterns in the changes of phase equilibria and thermodynamic properties of solutions are established, depending on the compositions and temperatures of the systems. Liquid-vapor equilibria in the systems are described using the equations of Wilson and the NRTL (Non-Random Two-Liquid Model).

  1. The vapor-liquid interface potential of (multi)polar fluids and its influence on ion solvation.

    Science.gov (United States)

    Horváth, Lorand; Beu, Titus; Manghi, Manoel; Palmeri, John

    2013-04-21

    The interface between the vapor and liquid phase of quadrupolar-dipolar fluids is the seat of an electric interfacial potential whose influence on ion solvation and distribution is not yet fully understood. To obtain further microscopic insight into water specificity we first present extensive classical molecular dynamics simulations of a series of model liquids with variable molecular quadrupole moments that interpolates between SPC/E water and a purely dipolar liquid. We then pinpoint the essential role played by the competing multipolar contributions to the vapor-liquid and the solute-liquid interface potentials in determining an important ion-specific direct electrostatic contribution to the ionic solvation free energy for SPC/E water-dominated by the quadrupolar and dipolar parts-beyond the dominant polarization one. Our results show that the influence of the vapor-liquid interfacial potential on ion solvation is strongly reduced due to the strong partial cancellation brought about by the competing solute-liquid interface potential.

  2. Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

    Science.gov (United States)

    Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

    2008-01-01

    Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

  3. Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C5H8O Cyclopentanone (EVLM1111, LB5655_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C5H8O Cyclopentanone (EVLM1111, LB5655_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  4. Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C6H10O Cyclohexanone (EVLM1111, LB5654_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C6H10O Cyclohexanone (EVLM1111, LB5654_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  5. Molecular simulation of the thermodynamic, structural, and vapor-liquid equilibrium properties of neon.

    Science.gov (United States)

    Vlasiuk, Maryna; Frascoli, Federico; Sadus, Richard J

    2016-09-14

    The thermodynamic, structural, and vapor-liquid equilibrium properties of neon are comprehensively studied using ab initio, empirical, and semi-classical intermolecular potentials and classical Monte Carlo simulations. Path integral Monte Carlo simulations for isochoric heat capacity and structural properties are also reported for two empirical potentials and one ab initio potential. The isobaric and isochoric heat capacities, thermal expansion coefficient, thermal pressure coefficient, isothermal and adiabatic compressibilities, Joule-Thomson coefficient, and the speed of sound are reported and compared with experimental data for the entire range of liquid densities from the triple point to the critical point. Lustig's thermodynamic approach is formally extended for temperature-dependent intermolecular potentials. Quantum effects are incorporated using the Feynman-Hibbs quantum correction, which results in significant improvement in the accuracy of predicted thermodynamic properties. The new Feynman-Hibbs version of the Hellmann-Bich-Vogel potential predicts the isochoric heat capacity to an accuracy of 1.4% over the entire range of liquid densities. It also predicts other thermodynamic properties more accurately than alternative intermolecular potentials.

  6. Molecular simulation of the thermodynamic, structural, and vapor-liquid equilibrium properties of neon

    Science.gov (United States)

    Vlasiuk, Maryna; Frascoli, Federico; Sadus, Richard J.

    2016-09-01

    The thermodynamic, structural, and vapor-liquid equilibrium properties of neon are comprehensively studied using ab initio, empirical, and semi-classical intermolecular potentials and classical Monte Carlo simulations. Path integral Monte Carlo simulations for isochoric heat capacity and structural properties are also reported for two empirical potentials and one ab initio potential. The isobaric and isochoric heat capacities, thermal expansion coefficient, thermal pressure coefficient, isothermal and adiabatic compressibilities, Joule-Thomson coefficient, and the speed of sound are reported and compared with experimental data for the entire range of liquid densities from the triple point to the critical point. Lustig's thermodynamic approach is formally extended for temperature-dependent intermolecular potentials. Quantum effects are incorporated using the Feynman-Hibbs quantum correction, which results in significant improvement in the accuracy of predicted thermodynamic properties. The new Feynman-Hibbs version of the Hellmann-Bich-Vogel potential predicts the isochoric heat capacity to an accuracy of 1.4% over the entire range of liquid densities. It also predicts other thermodynamic properties more accurately than alternative intermolecular potentials.

  7. Deconstructing Temperature Gradients across Fluid Interfaces: The Structural Origin of the Thermal Resistance of Liquid-Vapor Interfaces

    Science.gov (United States)

    Muscatello, Jordan; Chacón, Enrique; Tarazona, Pedro; Bresme, Fernando

    2017-07-01

    The interfacial thermal resistance determines condensation-evaporation processes and thermal transport across material-fluid interfaces. Despite its importance in transport processes, the interfacial structure responsible for the thermal resistance is still unknown. By combining nonequilibrium molecular dynamics simulations and interfacial analyses that remove the interfacial thermal fluctuations we show that the thermal resistance of liquid-vapor interfaces is connected to a low density fluid layer that is adsorbed at the liquid surface. This thermal resistance layer (TRL) defines the boundary where the thermal transport mechanism changes from that of gases (ballistic) to that characteristic of dense liquids, dominated by frequent particle collisions involving very short mean free paths. We show that the thermal conductance is proportional to the number of atoms adsorbed in the TRL, and hence we explain the structural origin of the thermal resistance in liquid-vapor interfaces.

  8. Influence of liquid water and water vapor on antimisting kerosene (AMK)

    Science.gov (United States)

    Yavrouian, A. H.; Sarolouki, M.; Sarohia, V.

    1983-01-01

    Experiments have been performed to evaluate the compatibility of liquid water and water vapor with antimisting kerosenes (AMK) containing polymer additive FM-9 developed by Imperial Chemical Industries. This effort consists of the determination of water solubility in AMK, influence of water on restoration (degradation) of AMK, and effect of water on standard AMK quality control methods. The principal conclusions of this investigation are: (1) the uptake of water in AMK critically depends upon the degree of agitation and can be as high as 1300 ppm at 20 C, (2) more than 250 to 300 ppm of water in AMK causes an insoluble second phase to form. The amount of this second phase depends on fuel temperature, agitation, degree of restoration (degradation) and the water content of the fuel, (3) laboratory scale experiments indicate precipitate formation when water vapor comes in contact with cold fuel surfaces at a much lower level of water (125 to 150 ppm), (4) precipitate formation is very pronounced in these experiments where humid air is percolated through a cold fuel (-20 C), (5) laboratory tests further indicate that water droplet settling time is markedly reduced in AMK as compared to jet A, (6) limited low temperature testing down to -30 C under laboratory conditions indicates the formation of stable, transparent gels.

  9. Correlation of the vapor pressure isotope effect with molecular force fields in the liquid state

    Energy Technology Data Exchange (ETDEWEB)

    Pollin, J.S.; Ishida, T.

    1976-07-01

    The present work is concerned with the development and application of a new model for condensed phase interactions with which the vapor pressure isotope effect (vpie) may be related to molecular forces and structure. The model considers the condensed phase as being represented by a cluster of regularly arranged molecules consisting of a central molecule and a variable number of molecules in the first coordination shell. The methods of normal coordinate analysis are used to determine the modes of vibration of the condensed phase cluster from which, in turn, the isotopic reduced partition function can be calculated. Using the medium cluster model, the observed vpie for a series of methane isotopes has been successfully reproduced with better agreement with experiment than has been possible using the simple cell model. We conclude, however, that insofar as the medium cluster model provides a reasonable picture of the liquid state, the vpie is not sufficiently sensitive to molecular orientation to permit an experimental determination of intermolecular configuration in the condensed phase through measurement of isotopic pressure ratios. The virtual independence of vapor pressure isotope effects on molecular orientation at large cluster sizes is a demonstration of the general acceptability of the cell model assumptions for vpie calculations.

  10. Curvature-dependence of the liquid-vapor surface tension beyond the Tolman approximation

    CERN Document Server

    Bruot, Nicolas

    2016-01-01

    Surface tension is a macroscopic manifestation of the cohesion of matter, and its value $\\sigma_\\infty$ is readily measured for a flat liquid-vapor interface. For interfaces with a small radius of curvature $R$, the surface tension might differ from $\\sigma_\\infty$. The Tolman equation, $\\sigma(R) = \\sigma_\\infty / (1 + 2 \\delta/R)$, with $\\delta$ a constant length, is commonly used to describe nanoscale phenomena such as nucleation. Here we report experiments on nucleation of bubbles in ethanol and n-heptane, and their analysis in combination with their counterparts for the nucleation of droplets in supersaturated vapors, and with water data. We show that neither a constant surface tension nor the Tolman equation can consistently describe the data. We also investigate a model including $1/R$ and $1/R^2$ terms in $\\sigma(R)$. We describe a general procedure to obtain the coefficients of these terms from detailed nucleation experiments. This work explains the conflicting values obtained for the Tolman length i...

  11. Investigation of Vapor-Liquid Nucleation for Associating Fluids by Density Gradient Theory

    Institute of Scientific and Technical Information of China (English)

    FU Dong; LIU Jianmin

    2009-01-01

    An equation of state (EOS) applicable to both the uniform and non-uniform associating fluids was established by using the density-gradient expansion, in which the influence parameter κis formulated as a function of tempera-ture. The molecular parameters were regressed by fitting to the experimental data of vapor pressures and liquid den-sities. Within the framework of density gradient theory (DGT), the nucleation rates for water, heavy water, metha-nol, ethanol, 1-propanoi, 1-butanol, 1-pentanol and 1-hexanol were calculated. The results were satisfactory com-pared with the experimental data. Our study shows that DGT preserves all the advantages of density functional the-ory (DFT) in capturing the structure and properties of nucleus but gives much more accurate nucleation rates by adjusting the influence parameter.

  12. Broad compositional tunability of indium tin oxide nanowires grown by the vapor-liquid-solid mechanism

    Directory of Open Access Journals (Sweden)

    M. Zervos

    2014-05-01

    Full Text Available Indium tin oxide nanowires were grown by the reaction of In and Sn with O2 at 800 °C via the vapor-liquid-solid mechanism on 1 nm Au/Si(001. We obtain Sn doped In2O3 nanowires having a cubic bixbyite crystal structure by using In:Sn source weight ratios > 1:9 while below this we observe the emergence of tetragonal rutile SnO2 and suppression of In2O3 permitting compositional and structural tuning from SnO2 to In2O3 which is accompanied by a blue shift of the photoluminescence spectrum and increase in carrier lifetime attributed to a higher crystal quality and Fermi level position.

  13. Lattice boltzmann study on the contact angle and contact line dynamics of liquid-vapor interfaces.

    Science.gov (United States)

    Zhang, Junfeng; Kwok, Daniel Y

    2004-09-14

    The moving contact line problem of liquid-vapor interfaces was studied using a mean-field free-energy lattice Boltzmann method recently proposed [Phys. Rev. E 2004, 69, 032602]. We have examined the static and dynamic interfacial behaviors by means of the bubble and capillary wave tests and found that both the Laplace equation of capillarity and the dispersion relation were satisfied. Dynamic contact angles followed the general trend of contact line velocity observed experimentally and can be described by Blake's theory. The velocity fields near the interface were also obtained and are in good agreement with fluid mechanics and molecular dynamics studies. Our simulations demonstrated that incorporating interfacial effects into the lattice Boltzmann model can be a valuable and powerful alternative in interfacial studies.

  14. Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

    KAUST Repository

    Vakarelski, Ivan Uriev

    2016-09-08

    The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re∼3×105. A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ∼600 to 105. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape. © 2016 American Physical Society.

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

    Directory of Open Access Journals (Sweden)

    M.González-Melchor

    2004-01-01

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

  16. Rapid thermal annealing effects on tin oxide nanowires prepared by vapor-liquid-solid technique.

    Science.gov (United States)

    Kar, Ayan; Yang, Jianyong; Dutta, Mitra; Stroscio, Michael A; Kumari, Jyoti; Meyyappan, M

    2009-02-11

    Tin oxide nanowires have been grown on p-type silicon substrates using a gold-catalyst-assisted vapor-liquid-solid growth process. The nanowires were annealed in the presence of oxygen at 700 degrees C for different time intervals. The changes in material properties of the nanowires after annealing were investigated using various characterization techniques. Annealing improves the crystal quality of the nanowires as seen from Raman spectroscopy analysis. Photoluminescence (PL) data indicates a decrease in the oxygen vacancies and defects after annealing, affecting the luminescence from the nanowires. In addition, x-ray photoelectron spectroscopy (XPS) was used to obtain the changes in the tin and oxygen atomic concentrations before and after annealing, from which the stoichiometry was calculated.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    Monte Carlo simulation methods for determining fluid- and crystal-phase chemical potentials are used for the first time to calculate liquid water-methane hydrate-methane vapor phase equilibria from knowledge of atomistic interaction potentials alone. The water and methane molecules are modeled...... using the TIP4P/ice potential and a united-atom Lennard-Jones potential. respectively. The equilibrium calculation method for this system has three components, (i) thermodynamic integration from a supercritical ideal gas to obtain the fluid-phase chemical potentials. (ii) calculation of the chemical...... potential of the zero-occupancy hydrate system using thermodynamic integration from an Einstein crystal reference state, and (iii) thermodynamic integration to obtain the water and guest molecules' chemical potentials as a function of the hydrate occupancy. The three-phase equilibrium curve is calculated...

  18. Substrate elastic deformation due to vertical component of liquid-vapor interfacial tension

    Institute of Scientific and Technical Information of China (English)

    Ying-song YU; Ya-pu ZHAO

    2012-01-01

    Young's equation is a fundamental equation in capillarity and wetting,which reflects the balance of the horizontal components of the three interfacial tensions with the contact angle (CA).However,it does not consider the vertical component of the liquid-vapor interfacial tension (VCLVIT).It is now well understood that the VCLVIT causes the elastic deformation of the solid substrate,which plays a significant role in the fabrication of the microfluidic devices because of the wide use of the soft materials.In this paper,the theoretical,experimental,and numerical aspects of the problem are reviewed. The effects of the VCLVIT-induced surface deformation on the wetting and spreading,the deflection of the microcantilever,and the elasto-capillarity and electroelasto-capillarity are discussed.Besides a brief review on the historical development and the recent advances,some suggestions on the future research are also provided.

  19. 40 CFR 265.1061 - Alternative standards for valves in gas/vapor service or in light liquid service: percentage of...

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service or in light liquid service: percentage of valves allowed to leak. 265.1061 Section... FACILITIES Air Emission Standards for Equipment Leaks § 265.1061 Alternative standards for valves in gas/vapor service or in light liquid service: percentage of valves allowed to leak. (a) An owner or...

  20. 40 CFR 265.1062 - Alternative standards for valves in gas/vapor service or in light liquid service: skip period...

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service or in light liquid service: skip period leak detection and repair. 265.1062 Section... FACILITIES Air Emission Standards for Equipment Leaks § 265.1062 Alternative standards for valves in gas/vapor service or in light liquid service: skip period leak detection and repair. (a) An owner...

  1. 40 CFR 264.1061 - Alternative standards for valves in gas/vapor service or in light liquid service: percentage of...

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service or in light liquid service: percentage of valves allowed to leak. 264.1061 Section... Emission Standards for Equipment Leaks § 264.1061 Alternative standards for valves in gas/vapor service or in light liquid service: percentage of valves allowed to leak. (a) An owner or operator subject...

  2. 40 CFR 264.1062 - Alternative standards for valves in gas/vapor service or in light liquid service: skip period...

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service or in light liquid service: skip period leak detection and repair. 264.1062 Section... Emission Standards for Equipment Leaks § 264.1062 Alternative standards for valves in gas/vapor service or in light liquid service: skip period leak detection and repair. (a) An owner or operator subject...

  3. Fragile to strong crossover at the Widom line in supercooled aqueous solutions of NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, P. [Dipartimento di Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy and INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); Corradini, D.; Rovere, M., E-mail: rovere@fis.uniroma3.it [Dipartimento di Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy)

    2013-11-28

    We study by molecular dynamics simulations the dynamical properties of an aqueous solution of NaCl at a concentration of 0.67 mol/kg upon supercooling. In a previous study of the same ionic solution, we have located the liquid-liquid critical point (LLCP) and determined the Widom line connected to the liquid-liquid transition. We present here the results obtained from the study of the self-intermediate scattering function in a large range of temperatures and densities approaching the LLCP. The structural relaxation is in agreement with the mode coupling theory (MCT) in the region of mild supercooling. In the deeper supercooled region the α-relaxation time as function of temperature deviates from the MCT power law prediction showing a crossover from a fragile to a strong behavior. This crossover is found upon crossing the Widom line. The same trend was found in bulk water upon supercooling and it appears almost unchanged by the interaction with ions apart from a shift in the thermodynamic plane toward lower pressures and higher temperatures. These results show that the phenomenology of supercooled water transfers from bulk to solution where the study of the supercooled region is experimentally less difficult.

  4. Fragile to strong crossover at the Widom line in supercooled aqueous solutions of NaCl.

    Science.gov (United States)

    Gallo, P; Corradini, D; Rovere, M

    2013-11-28

    We study by molecular dynamics simulations the dynamical properties of an aqueous solution of NaCl at a concentration of 0.67 mol/kg upon supercooling. In a previous study of the same ionic solution, we have located the liquid-liquid critical point (LLCP) and determined the Widom line connected to the liquid-liquid transition. We present here the results obtained from the study of the self-intermediate scattering function in a large range of temperatures and densities approaching the LLCP. The structural relaxation is in agreement with the mode coupling theory (MCT) in the region of mild supercooling. In the deeper supercooled region the α-relaxation time as function of temperature deviates from the MCT power law prediction showing a crossover from a fragile to a strong behavior. This crossover is found upon crossing the Widom line. The same trend was found in bulk water upon supercooling and it appears almost unchanged by the interaction with ions apart from a shift in the thermodynamic plane toward lower pressures and higher temperatures. These results show that the phenomenology of supercooled water transfers from bulk to solution where the study of the supercooled region is experimentally less difficult.

  5. Computer simulation of liquid-vapor coexistence of confined quantum fluids

    Energy Technology Data Exchange (ETDEWEB)

    Trejos, Víctor M.; Gil-Villegas, Alejandro, E-mail: gil@fisica.ugto.mx; Martinez, Alejandro [División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato (Mexico)

    2013-11-14

    The liquid-vapor coexistence (LV) of bulk and confined quantum fluids has been studied by Monte Carlo computer simulation for particles interacting via a semiclassical effective pair potential V{sub eff}(r) = V{sub LJ} + V{sub Q}, where V{sub LJ} is the Lennard-Jones 12-6 potential (LJ) and V{sub Q} is the first-order Wigner-Kirkwood (WK-1) quantum potential, that depends on β = 1/kT and de Boer's quantumness parameter Λ=h/σ√(mε), where k and h are the Boltzmann's and Planck's constants, respectively, m is the particle's mass, T is the temperature of the system, and σ and ε are the LJ potential parameters. The non-conformal properties of the system of particles interacting via the effective pair potential V{sub eff}(r) are due to Λ, since the LV phase diagram is modified by varying Λ. We found that the WK-1 system gives an accurate description of the LV coexistence for bulk phases of several quantum fluids, obtained by the Gibbs Ensemble Monte Carlo method (GEMC). Confinement effects were introduced using the Canonical Ensemble (NVT) to simulate quantum fluids contained within parallel hard walls separated by a distance L{sub p}, within the range 2σ ⩽ L{sub p} ⩽ 6σ. The critical temperature of the system is reduced by decreasing L{sub p} and increasing Λ, and the liquid-vapor transition is not longer observed for L{sub p}/σ < 2, in contrast to what has been observed for the classical system.

  6. On the vapor-liquid equilibrium of attractive chain fluids with variable degree of molecular flexibility.

    Science.gov (United States)

    van Westen, Thijs; Vlugt, Thijs J H; Gross, Joachim

    2015-06-14

    We study the isotropic (vapor and liquid) phase behavior of attractive chain fluids. Special emphasis is placed on the role of molecular flexibility, which is studied by means of a rod-coil model. Two new equations of state (EoSs) are developed for square-well- (SW) and Lennard-Jones (LJ) chain fluids. The EoSs are developed by applying the perturbation theory of Barker and Henderson (BH) to a reference fluid of hard chain molecules. The novelty of the approach is based on (1) the use of a recently developed hard-chain reference EoS that explicitly incorporates the effects of molecular flexibility, (2) the use of recent molecular simulation data for the radial distribution function of hard-chain fluids, and (3) a newly developed effective segment size, which effectively accounts for the soft repulsion between segments of LJ chains. It is shown that the effective segment size needs to be temperature-, density-, and chain-length dependent. To obtain a simplified analytical EoS, the perturbation terms are fitted by polynomials in density (SW and LJ), chain length (SW and LJ), and temperature (only for LJ). It is shown that the equations of state result in an accurate description of molecular simulation data for vapor-liquid equilibria (VLE) and isotherms of fully flexible SW- and LJ chain fluids and their mixtures. To evaluate the performance of the equations of state in describing the effects of molecular flexibility on VLE, we present new Monte Carlo simulation results for the VLE of rigid linear- and partially flexible SW- and LJ chain fluids. For SW chains, the developed EoS is in a good agreement with simulation results. For increased rigidity of the chains, both theory and simulations predict an increase of the VL density difference and a slight increase of the VL critical temperature. For LJ chains, the EoS proves incapable of reproducing part of these trends.

  7. Ultrafast solid-liquid-vapor phase change of a gold film induced by pico- to femtosecond lasers

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jing; Zhang, Yuwen; Chen, J.K. [University of Missouri, Department of Mechanical and Aerospace Engineering, Columbia, MO (United States)

    2009-06-15

    Melting, vaporization and resolidification processes of thin gold film irradiated by a femtosecond pulse laser are studied numerically. The nonequilibrium heat transfer in electrons and lattice is described using a two-temperature model. The solid-liquid interfacial velocity, as well as elevated melting temperature and depressed solidification temperature, is obtained by considering the interfacial energy balance and nucleation dynamics. An iterative procedure based on energy balance and gas kinetics law to track the location of liquid-vapor interface is utilized to obtain the material removal by vaporization. The effect of surface heat loss by thermal radiation was discussed. The influences of laser fluence and duration on the evaporation process are studied. Results show that higher laser fluence and shorter laser pulse width lead to higher interfacial temperature, deeper melting and ablation depths. (orig.)

  8. Evaluation of E-Cigarette Liquid Vapor and Mainstream Cigarette Smoke after Direct Exposure of Primary Human Bronchial Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Stefanie Scheffler

    2015-04-01

    Full Text Available E-cigarettes are emerging products, often described as “reduced-risk” nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact  module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5–8 times lower and the oxidative stress levels 4.5–5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user.

  9. Hydrogen Bonding in Ion-pair Molecules in Vapors over ionic liquids, studied by Raman Spectroscopy and ab initio Calculations

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    -H-Br] [ref 2] and (3) the 1-methylimidazolium ethano-ate, [mim-H-O2CCH3] found [ref 3] to have a less likely existence in the vapor of the corresponding liquid in ampouls at ~200°C (Fig. 2). Experimental Raman results will be compared to ab initio calculated spectra. Fig. 1. Likely gaseous ion pair molecule...

  10. Heat transfer for Marangoni convection over a vapor-liquid interface due to an imposed temperature gradient

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan Sheng; Liancun Zheng; Xinxin Zhang

    2008-01-01

    A similarity analysis for Marangoni convection induced flow over a vapor-liquid interface due to an imposed temperature gradient was carried out. The analysis assumes that the surface tension varies linearly with temperature but the temperature variation is a power law function of the location. The similarity solutions are presented numerically and the associated transfer characteristics are discussed.

  11. Vapor pressures of 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids with long alkyl chains.

    Science.gov (United States)

    Rocha, Marisa A A; Coutinho, João A P; Santos, Luís M N B F

    2014-10-01

    This work presents the vapor pressure at several temperatures for the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide series, [CN/2CN/2im][NTf2] (N = 14, 16, 18, and 20), measured by a Knudsen effusion method combined with a quartz crystal microbalance. The thermodynamic properties of vaporization of the ionic liquids under study are analysed together with the results obtained previously for the shorter alkyl chain length [CN/2CN/2im][NTf2] (N = 2, 4, 6, 8, 10, and 12), in order to evaluate the effect of the alkyl side chains of the cation and to get additional insights concerning the nanostructuration of ionic liquids. The symmetry effect is explored, based on the comparison with the asymmetric imidazolium based ionic liquids, [CN-1C1im][NTf2]. A trend shift on the thermodynamic properties of vaporization along the alkyl side chains of the extended symmetric ionic liquids, around [C6C6im][NTf2], was detected. An intensification of the odd-even effect was observed starting from [C6C6im][NTf2], with higher enthalpies and entropies of vaporization for the odd numbered ionic liquids, [C7C7im][NTf2] and [C9C9im][NTf2]. Similar, but less pronounced, odd-even effect was found for the symmetric ionic liquids with lower alkyl side chains length, [CN/2CN/2im][NTf2] (with N = 4, 6, 8, 10, and 12). This effect is related with the predominant orientation of the terminal methyl group of the alkyl chain to the imidazolium ring and their influence in the cation-anion interaction. The same Critical Alkyl length at the hexyl, (C6C1and C6C6) was found for both asymmetric and symmetric series indicating that the nanostructuration of the ionic liquids is related with alkyl chain length.

  12. Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C3H7NO N,N-Dimethylmethanamide (EVLM1231, LB5709_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C3H7NO N,N-Dimethylmethanamide (EVLM1231, LB5709_E)' providing data from direct measurement of temperature and mole fraction in vapor phase at variable mole fraction in liquid phase and constant pressure.

  13. Numerical studies of the effects of jet-induced mixing on liquid-vapor interface condensation

    Science.gov (United States)

    Lin, Chin-Shun

    1989-01-01

    Numerical solutions of jet-induced mixing in a partially full cryogenic tank are presented. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear-free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to solve the nondimensional form of steady state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of above stated parameters on the condensation Nusselt and Stanton numbers which characterize the steady-state interface condensation process are investigated. Detailed analysis to gain a better understanding of the fundamentals of fluid mixing and interface condensation is performed.

  14. Ion spatial distributions at the liquid-vapor interface of aqueous potassium fluoride solutions.

    Science.gov (United States)

    Brown, Matthew A; D'Auria, Raffaella; Kuo, I-F William; Krisch, Maria J; Starr, David E; Bluhm, Hendrik; Tobias, Douglas J; Hemminger, John C

    2008-08-28

    X-Ray photoemission spectroscopy operating under ambient pressure conditions is used to probe ion distributions throughout the interfacial region of a free-flowing aqueous liquid micro-jet of 6 M potassium fluoride. Varying the energy of the ejected photoelectrons by carrying out experiments as a function of X-ray wavelength measures the composition of the aqueous-vapor interfacial region at various depths. The F(-) to K(+) atomic ratio is equal to unity throughout the interfacial region to a depth of 2 nm. The experimental ion profiles are compared with the results of a classical molecular dynamics simulation of a 6 M aqueous KF solution employing polarizable potentials. The experimental results are in qualitative agreement with the simulations when integrated over an exponentially decaying probe depth characteristic of an APPES experiment. First principles molecular dynamics simulations have been used to calculate the potential of mean force for moving a fluoride anion across the air-water interface. The results show that the fluoride anion is repelled from the interface, consistent with the depletion of F(-) at the interface revealed by the APPES experiment and polarizable force field-based molecular dynamics simulation. Together, the APPES and MD simulation data provide a detailed description of the aqueous-vapor interface of alkali fluoride systems. This work offers the first direct observation of the ion distribution at an aqueous potassium fluoride solution interface. The current experimental results are compared to those previously obtained for saturated solutions of KBr and KI to underscore the strong difference in surface propensity between soft/large and hard/small halide ions in aqueous solution.

  15. HIGH PRESSURE VAPOR-LIQUID EQUILIBRIA OF PALM FATTY ACIDS DISTILLATES-CARBON DIOXIDE SYSTEM

    Directory of Open Access Journals (Sweden)

    Nélio T. MACHADO

    1997-12-01

    Full Text Available Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid and unsaturated (oleic+linoleic acids fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.Foi investigado experimentalmente o equilíbrio líquido-vapor para o sistema Destilado Ácido de Óleo de Palma (PFAD/Dióxido de Carbono, nas temperaturas de 333, 353 e 373 K e pressões de 20, 23, 26 e 29 MPa, usando-se o método estático. Os dados experimentais do sistema pseudo-binário PFAD/CO2 foram correlacionados com a equação de estado de Redlich-Kwong do pacote computacional ASPEN. O modelo reproduz bem os resultados experimentais. A seletividade obtida indica que o CO2 supercrítico é um solvente razoável para a separação em coluna multi-estágio e contínua, do ácido graxo saturado (ácido palmítico daqueles insaturados (ácido oleico e ácido linoleico contidos no PFAD.

  16. Fluid inclusions in vadose cement with consistent vapor to liquid ratios, Pleistocene Miami Limestone, southeastern Florida

    Science.gov (United States)

    Barker, C.E.; Halley, R.B.

    1988-01-01

    Vadose cements in the Late Pleistocene Miami Limestone contain regions with two-phase aqueous fluid inclusions that have consistent vapor to liquid (V-L) ratios. When heated, these seemingly primary inclusions homogenize to a liquid phase in a range between 75??C and 130??C (mean = 100??C) and have final melting temperatures between -0.3?? and 0.0??C. The original distribution of Th was broadened during measurements because of fluid inclusion reequilibration. The narrow range of Th in these fluid inclusions suggest unusually consistent V-L ratios. They occur with small, obscure, single phase liquid-filled inclusions, which infer a low temperature origin (less than 60??C), and contradict the higher temperature origin implied by the two phase inclusions. The diagenetic environment producing these seemingly primary fluid inclusions can be inferred from the origin of the host calcite enclosing them. The ??18O composition of these cements (-4 to-5.5%., PDB) and the fresh water in the fluid inclusions are consistent with precipitation from low-temperature meteoric water. The carbon-isotope composition of the vadose cements that contain only rare two-phase fluid inclusions are comparable to the host rock matrix (??13C between 0 and +4%., PDB). Cements that contain common two-phase fluid-inclusions have a distinctly lighter carbon isotopic composition of -3 to -5%.. The carbon isotope composition of cements that contain common two-phase inclusions are about 6%. lighter than those of other vadose cements; models of early meteoric diagenesis indicate that this is the result of precipitation from water that has been influenced by soil gas CO2. Our hypothesis is that the primary fluid inclusions, those with consistent V-L ratios and the single-phase liquid inclusions, form at near-surface temperature (25??C) and pressure when consistent proportions of soil gas and meteoric water percolating through the vadose zone are trapped within elongate vacuoles. This study corroborates

  17. CRYOCHEM, Thermodynamic Model for Cryogenic Chemical Systems: Solid-Vapor and Solid-Liquid-Vapor Phase Equilibria Toward Applications on Titan and Pluto

    Science.gov (United States)

    Tan, S. P.; Kargel, J. S.; Adidharma, H.; Marion, G. M.

    2014-12-01

    Until in-situ measurements can be made regularly on extraterrestrial bodies, thermodynamic models are the only tools to investigate the properties and behavior of chemical systems on those bodies. The resulting findings are often critical in describing physicochemical processes in the atmosphere, surface, and subsurface in planetary geochemistry and climate studies. The extremely cold conditions on Triton, Pluto and other Kuiper Belt Objects, and Titan introduce huge non-ideality that prevents conventional models from performing adequately. At such conditions, atmospheres as a whole—not components individually—are subject to phase equilibria with their equilibrium solid phases or liquid phases or both. A molecular-based thermodynamic model for cryogenic chemical systems, referred to as CRYOCHEM, the development of which is still in progress, was shown to reproduce the vertical composition profile of Titan's atmospheric methane measured by the Huygens probe (Tan et al., Icarus 2013, 222, 53). Recently, the model was also used to describe Titan's global circulation where the calculated composition of liquid in Ligeia Mare is consistent with the bathymetry and microwave absorption analysis of T91 Cassini fly-by data (Tan et al., 2014, submitted). Its capability to deal with equilibria involving solid phases has also been demonstrated (Tan et al., Fluid Phase Equilib. 2013, 360, 320). With all those previous works done, our attention is now shifting to the lower temperatures in Titan's tropopause and on Pluto's surface, where much technical development remains for CRYOCHEM to assure adequate performance at low temperatures. In these conditions, solid-vapor equilibrium (SVE) is the dominant phase behavior that determines the composition of the atmosphere and the existing ices. Another potential application is for the subsurface phase equilibrium, which also involves liquid, thus three-phase equilibrium: solid-liquid-vapor (SLV). This presentation will discuss the

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

    Science.gov (United States)

    Palchowdhury, Sourav; Bhargava, B L

    2015-08-14

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

  19. Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

    Science.gov (United States)

    Amde, Meseret; Liu, Jing-Fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2016-01-01

    Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples.

  20. Combined effect of carbon dioxide and sulfur on vapor-liquid partitioning of metals in hydrothermal systems

    Science.gov (United States)

    Kokh, Maria A.; Lopez, Mathieu; Gisquet, Pascal; Lanzanova, Aurélie; Candaudap, Frédéric; Besson, Philippe; Pokrovski, Gleb S.

    2016-08-01

    Although CO2 is a ubiquitous volatile in geological fluids typically ranging from a few to more than 50 wt%, its effect on metal vapor-liquid fractionation during fluid boiling and immiscibility phenomena in the Earth's crust remains virtually unknown. Here we conducted first experiments to quantify the influence of CO2 on the partition of different metals in model water + salt + sulfur + CO2 systems at 350 °C and CO2 pressures up to 100 bar, which are typical conditions of formation of many hydrothermal ore deposits. In addition, we performed in situ Raman spectroscopy measurements on these two-phase systems, to determine sulfur and carbon speciation in the liquid and vapor phases. Results show that, in S-free systems and across a CO2 concentration range of 0-50 wt% in the vapor phase, the absolute vapor-liquid partitioning coefficients of metals (Kvap/liq = Cvap/Cliq, where C is the mass concentration of the metal in the corresponding vapor and liquid phase) are in the range 10-6-10-5 for Mo; 10-4-10-3 for Na, K, Cu, Fe, Zn, Au; 10-3-10-2 for Si; and 10-4-10-1 for Pt. With increasing CO2 from 0 to 50 wt%, Kvap/liq values decrease for Fe, Cu and Si by less than one order of magnitude, remain constant within errors (±0.2 log unit) for Na, K and Zn, and increase by 0.5 and 2 orders of magnitude, respectively for Au and Pt. The negative effect of CO2 on the partitioning of some metals is due to weakening of hydration of chloride complexes of some metals (Cu, Fe) in the vapor phase and/or salting-in effects in the liquid phase (Si), whereas both phenomena are negligible for complexes of other metals (Na, K, Zn, Mo). The only exception is Pt (and in a lesser extent Au), which partitions significantly more to the vapor of S-free systems in the presence of CO2, likely due to formation of volatile carbonyl (CO) complexes. In the S-bearing system, with H2S content of 0.1-1.0 wt% in the vapor, Kvap/liq values of Cu, Fe, Mo, and Au are in the range 0.01-0.1, those of Pt 0

  1. Calculation of liquid water-hydrate-methane vapor phase equilibria from molecular simulations.

    Science.gov (United States)

    Jensen, Lars; Thomsen, Kaj; von Solms, Nicolas; Wierzchowski, Scott; Walsh, Matthew R; Koh, Carolyn A; Sloan, E Dendy; Wu, David T; Sum, Amadeu K

    2010-05-06

    Monte Carlo simulation methods for determining fluid- and crystal-phase chemical potentials are used for the first time to calculate liquid water-methane hydrate-methane vapor phase equilibria from knowledge of atomistic interaction potentials alone. The water and methane molecules are modeled using the TIP4P/ice potential and a united-atom Lennard-Jones potential, respectively. The equilibrium calculation method for this system has three components, (i) thermodynamic integration from a supercritical ideal gas to obtain the fluid-phase chemical potentials, (ii) calculation of the chemical potential of the zero-occupancy hydrate system using thermodynamic integration from an Einstein crystal reference state, and (iii) thermodynamic integration to obtain the water and guest molecules' chemical potentials as a function of the hydrate occupancy. The three-phase equilibrium curve is calculated for pressures ranging from 20 to 500 bar and is shown to follow the Clapeyron behavior, in agreement with experiment; coexistence temperatures differ from the latter by 4-16 K in the pressure range studied. The enthalpy of dissociation extracted from the calculated P-T curve is within 2% of the experimental value at corresponding conditions. While computationally intensive, simulations such as these are essential to map the thermodynamically stable conditions for hydrate systems.

  2. Vapor-Liquid Equilibrium of Carbon Dioxide + Ethanol: Experimental Measurements with Acoustic Method and Thermodynamic Modeling

    Directory of Open Access Journals (Sweden)

    Ana Mehl

    2011-01-01

    Full Text Available Phase behavior of systems composed by supercritical carbon dioxide and ethanol is of great interest, especially in the processes involving supercritical extraction in which ethanol is used as a cosolvent. The development of an apparatus, which is able to perform the measurements of vapor-liquid equilibrium (VLE at high pressure using a combination of the visual and the acoustic methods, was successful and was proven to be suited for determining the isothermal VLE data of this system. The acoustic method, based on the variation of the amplitude of an ultra-sound signal passing through a mixture during a phase transition, was applied to investigate the phase equilibria of the system carbon dioxide + ethanol at temperatures ranging from 298.2 K to 323.2 K and pressures from 3.0 MPa to 9.0 MPa. The VLE data were correlated with Peng-Robinson equation of state combined with two different mixing rules and the SAFT equations of state as well. The compositions calculated with the models are in good agreement with the experimental data for the isotherms evaluated.

  3. Thermodynamic models for vapor-liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures

    Science.gov (United States)

    Vrabec, Jadran; Kedia, Gaurav Kumar; Buchhauser, Ulrich; Meyer-Pittroff, Roland; Hasse, Hans

    2009-02-01

    For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 + O 2 + CO 2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2-rich region.

  4. Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

    Science.gov (United States)

    Wilson, M. A.; Pohorille, A.

    1997-01-01

    The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

  5. Thermodynamic Models for Vapor-Liquid Equilibria of Nitrogen+Oxygen+Carbon Dioxide at Low Temperatures

    CERN Document Server

    Vrabec, J; Buchhauser, U; Meyer-Pittroff, R; Hasse, H

    2009-01-01

    For the design and optimization of CO2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N2+O2+CO2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N2 and O2 in CO2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO2-rich region.

  6. A sharp interface method for compressible liquid-vapor flow with phase transition and surface tension

    Science.gov (United States)

    Fechter, Stefan; Munz, Claus-Dieter; Rohde, Christian; Zeiler, Christoph

    2017-05-01

    The numerical approximation of non-isothermal liquid-vapor flow within the compressible regime is a difficult task because complex physical effects at the phase interfaces can govern the global flow behavior. We present a sharp interface approach which treats the interface as a shock-wave like discontinuity. Any mixing of fluid phases is avoided by using the flow solver in the bulk regions only, and a ghost-fluid approach close to the interface. The coupling states for the numerical solution in the bulk regions are determined by the solution of local two-phase Riemann problems across the interface. The Riemann solution accounts for the relevant physics by enforcing appropriate jump conditions at the phase boundary. A wide variety of interface effects can be handled in a thermodynamically consistent way. This includes surface tension or mass/energy transfer by phase transition. Moreover, the local normal speed of the interface, which is needed to calculate the time evolution of the interface, is given by the Riemann solution. The interface tracking itself is based on a level-set method. The focus in this paper is the description of the two-phase Riemann solver and its usage within the sharp interface approach. One-dimensional problems are selected to validate the approach. Finally, the three-dimensional simulation of a wobbling droplet and a shock droplet interaction in two dimensions are shown. In both problems phase transition and surface tension determine the global bulk behavior.

  7. Direct-Liquid-Evaporation Chemical Vapor Deposition of Nanocrystalline Cobalt Metal for Nanoscale Copper Interconnect Encapsulation.

    Science.gov (United States)

    Feng, Jun; Gong, Xian; Lou, Xiabing; Gordon, Roy G

    2017-03-29

    In advanced microelectronics, precise design of liner and capping layers become critical, especially when it comes to the fabrication of Cu interconnects with dimensions lower than its mean free path. Herein, we demonstrate that direct-liquid-evaporation chemical vapor deposition (DLE-CVD) of Co is a promising method to make liner and capping layers for nanoscale Cu interconnects. DLE-CVD makes pure, smooth, nanocrystalline, and highly conformal Co films with highly controllable growth characteristics. This process allows full Co encapsulation of nanoscale Cu interconnects, thus stabilizing Cu against diffusion and electromigration. Electrical measurements and high-resolution elemental imaging studies show that the DLE-CVD Co encapsulation layer can improve the reliability and thermal stability of Cu interconnects. Also, with the high conductivity of Co, the DLE-CVD Co encapsulation layer have the potential to further decrease the power consumption of nanoscale Cu interconnects, paving the way for Cu interconnects with higher efficiency in future high-end microelectronics.

  8. Non-Ising-like effects in the liquid-vapor transition: Equations of state

    Science.gov (United States)

    Vause, C.; Sak, J.

    1980-06-01

    A Landau-Ginzburg-Wilson model is derived for a single-component fluid whose particles interact via a two-body potential. The effective Hamiltonian contains both even and odd powers in the order parameter (local fluid density). We study the effect of quintic interactions absent in the Ising model, and characterized by a new exponent φ5, on various singular thermodynamic functions near the critical point. Mean-field, scaling, and renormalization-group (in d=4-ɛ dimensions) theories are used to evaluate the non-Ising effects due to φ5. One of the main results of the asymmetry in this model is that it produces the leading singularity of the liquid-vapor coexistence diameter near the critical point: |t|β-φ5, where β is the usual order-parameter exponent and t is the reduced temp˙erature. The singularity |t|1-α (α being the specific heat exponent) predicted by earlier phenomenological theories is not present in this theory. The problems associated with observing the non-Ising effects are briefly discussed.

  9. Effects of Ultrasonic Waves on Vapor-Liquid Equilibrium of Cyclohexane/Benzene

    Directory of Open Access Journals (Sweden)

    Siti Kholijah Abdul Mudalip

    2011-01-01

    Full Text Available Separation of azeotropic mixtures is one of the most challenging separation processes in chemical industry. Special separation techniques such as azeotropic and extractive distillation are required to separate these mixtures. In this work, an innovative technique which incorporates ultrasonic waves during separation of Cyclohexane (Chx/ Benzene (Bz via distillation process was explored. The effects of ultrasonic wave at different intensities at 50, 100, 200 and 250 W/A.cm2 and at a fixed frequency of 40 kHz on vapor-liquid equilibrium (VLE of Chx/ Bz were investigated. Studies were also done to examine the effects of ultrasonic frequencies on the VLE data at 25 and 68 kHz. It was found that ultrasonic waves at 100 W/A.cm2 intensity and 25 kHz frequency gave the highest relative volatility, α at 2.505 and completely eliminated the azeotropic point. The results revealed that ultrasonic waves had potential to favourably manipulate α, and hence, the VLE of Chx/ Bz.

  10. Nickel oxide nanowires: vapor liquid solid synthesis and integration into a gas sensing device.

    Science.gov (United States)

    Kaur, N; Comini, E; Zappa, D; Poli, N; Sberveglieri, G

    2016-05-20

    In the field of advanced sensor technology, metal oxide nanostructures are promising materials due to their high charge carrier mobility, easy fabrication and excellent stability. Among all the metal oxide semiconductors, nickel oxide (NiO) is a p-type semiconductor with a wide band gap and excellent optical, electrical and magnetic properties, which has not been much investigated. Herein, we report the growth of NiO nanowires by using the vapor liquid solid (VLS) technique for gas sensing applications. Platinum, palladium and gold have been used as a catalyst for the growth of NiO nanowires. The surface morphology of the nanowires was investigated through scanning electron microscopy to find out which catalyst and growth conditions are best for the growth of nanowires. GI-XRD and Raman spectroscopies were used to confirm the crystalline structure of the material. Different batches of sensors have been prepared, and their sensing performances towards different gas species such as carbon monoxide, ethanol, acetone and hydrogen have been explored. NiO nanowire sensors show interesting and promising performances towards hydrogen.

  11. Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

    Science.gov (United States)

    Wilson, M. A.; Pohorille, A.

    1997-01-01

    The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

  12. DETERMINATION OF HEAT TRANSFER COEFFICIENTS FOR FRENCH PLASTIC SEMEN STRAW SUSPENDED IN STATIC NITROGEN VAPOR OVER LIQUID NITROGEN.

    Science.gov (United States)

    Santo, M V; Sansinena, M; Chirife, J; Zaritzky, N

    2015-01-01

    The use of mathematical models describing heat transfer during the freezing process is useful for the improvement of cryopreservation protocols. A widespread practice for cryopreservation of spermatozoa of domestic animal species consists of suspending plastic straws in nitrogen vapor before plunging into liquid nitrogen. Knowledge of surface heat transfer coefficient (h) is mandatory for computational modelling; however, h values for nitrogen vapor are not available. In the present study, surface heat transfer coefficients for plastic French straws immersed in nitrogen vapor over liquid nitrogen was determined; vertical and horizontal positions were considered. Heat transfer coefficients were determined from the measurement of time-temperature curves and from numerical solution of heat transfer partial differential equation under transient conditions using finite elements. The h values experimentally obtained for horizontal and vertically placed straws were compared to those calculated using correlations based on the Nusselt number for natural convection. For horizontal straws the average obtained value was h=12.5 ± 1.2 W m(2) K and in the case of vertical straws h=16 ± 2.48 W m(2) K. The numerical simulation validated against experimental measurements, combined with accurate h values provides a reliable tool for the prediction of freezing curves of semen-filled straws immersed in nitrogen vapor. The present study contributes to the understanding of the cryopreservation techniques for sperm freezing based on engineering concepts, improving the cooling protocols and the manipulation of the straws.

  13. Isomerization reaction dynamics and equilibrium at the liquid-vapor interface of water. A molecular-dynamics study

    Science.gov (United States)

    Benjamin, Ilan; Pohorille, Andrew

    1993-01-01

    The gauche-trans isomerization reaction of 1,2-dichloroethane at the liquid-vapor interface of water is studied using molecular-dynamics computer simulations. The solvent bulk and surface effects on the torsional potential of mean force and on barrier recrossing dynamics are computed. The isomerization reaction involves a large change in the electric dipole moment, and as a result the trans/gauche ratio is considerably affected by the transition from the bulk solvent to the surface. Reactive flux correlation function calculations of the reaction rate reveal that deviation from the transition-state theory due to barrier recrossing is greater at the surface than in the bulk water. This suggests that the system exhibits non-Rice-Ramsperger-Kassel-Marcus behavior due to the weak solvent-solute coupling at the water liquid-vapor interface.

  14. Vapor-liquid equilibria of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems

    Energy Technology Data Exchange (ETDEWEB)

    Mun, S.Y.; Lee, H.

    1999-12-01

    Vapor-liquid equilibrium data of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems were measured at 60, 160, 300, and 760 mmHg at temperatures ranging from 315 to 488 K. The apparatus used in this work is a modified still especially designed for the measurement of low-pressure VLE, in which both liquid and vapor are continuously recirculated. For the analysis of salt-containing solutions, a method incorporating refractometry and gravimetry was used. From the experimental measurements, the effect of lithium bromide on the VLE behavior of water + 1,3-propanediol was investigated. The experimental data of the salt-free system were successfully correlated using the Wilson, NRTL, and UNIQUAC models. In addition, the extended UNIQUAC model of Sander et al. was applied to the VLE calculation of salt-containing mixtures.

  15. Constructing a superhydrophobic surface on polydimethylsiloxane via spin coating and vapor-liquid sol-gel process.

    Science.gov (United States)

    Peng, Yu-Ting; Lo, Kuo-Feng; Juang, Yi-Je

    2010-04-06

    In this study, a superhydrophobic surface on polydimethylsiloxane (PDMS) substrate was constructed via the proposed vapor-liquid sol-gel process in conjunction with spin coating of dodecyltrichlorosilane (DTS). Unlike the conventional sol-gel process where the reaction takes place in the liquid phase, layers of silica (SiO(2)) particles were formed through the reaction between the reactant spin-coated on the PDMS surface and vapor of the acid solution. This led to the SiO(2) particles inlaid on the PDMS surface. Followed by subsequent spin coating of DTS solution, the wrinkle-like structure was formed, and the static contact angle of the water droplet on the surface could reach 162 degrees with 2 degrees sliding angle and less than 5 degrees contact angle hysteresis. The effect of layers of SiO(2) particles, concentrations of DTS solution and surface topography on superhydrophobicity of the surface is discussed.

  16. Vapor liquid equilibrium constants through a non-equation of state approach: methane-free aliphatic binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, T.H.; Thodos, G.

    1975-06-01

    Northwestern University developed an alternate method to help predict vapor-liquid equilibrium constants without an equation of state by using the fundamental properties associated with the pure-state components and the critical pressure of the mixture. The method consists of developing correlations to help predict K-constants for other aliphatic binary mixtures not containing methane from vapor-liquid equilibrium measurements available in the literature for the 3 binaries of the system ethane-butane-heptane. This approach was tested for 7 other binaries (ethane/n-hexane, propane/i-butane, propane/i-butane, propane/n-pentane, propane/i-pentane, poprane/n-decane, and propylene/i-butane). The K-values obtained displayed good agreement with experimental measurements, especially in the vicinity of the critical point.

  17. Isomerization reaction dynamics and equilibrium at the liquid-vapor interface of water. A molecular-dynamics study

    Science.gov (United States)

    Benjamin, Ilan; Pohorille, Andrew

    1993-01-01

    The gauche-trans isomerization reaction of 1,2-dichloroethane at the liquid-vapor interface of water is studied using molecular-dynamics computer simulations. The solvent bulk and surface effects on the torsional potential of mean force and on barrier recrossing dynamics are computed. The isomerization reaction involves a large change in the electric dipole moment, and as a result the trans/gauche ratio is considerably affected by the transition from the bulk solvent to the surface. Reactive flux correlation function calculations of the reaction rate reveal that deviation from the transition-state theory due to barrier recrossing is greater at the surface than in the bulk water. This suggests that the system exhibits non-Rice-Ramsperger-Kassel-Marcus behavior due to the weak solvent-solute coupling at the water liquid-vapor interface.

  18. Mathematical prediction of freezing times of bovine semen in straws placed in static vapor over liquid nitrogen.

    Science.gov (United States)

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

    2013-02-01

    A widespread practice in cryopreservation is to freeze spermatozoa by suspending the straws in stagnant nitrogen vapor over liquid nitrogen (N(2)V/LN(2)) for variable periods of time before plunging into liquid nitrogen (-196°C) for indefinite storage. A mathematical heat transfer model was developed to predict freezing times (phase change was considered) required for bull semen and extender packaged in 0.5ml plastic straws and suspended in static liquid nitrogen vapor. Thermophysical properties (i.e. thermal conductivity, specific heat, density, initial freezing temperature) of bovine semen and extender as a function of temperature were determined considering the water change of phase. The non-stationary heat transfer partial differential equations with variable properties (nonlinear mathematical problem) were numerically solved considering in series thermal resistances (semen suspension-straw) and the temperature profiles were obtained for both semen suspension and plastic straw. It was observed both the external heat transfer coefficient in stagnant nitrogen vapor and its temperature (controlled by the distance from the surface of liquid nitrogen to the straw) affected freezing times. The accuracy of the model to estimate freezing times of the straws was further confirmed by comparing with experimental literature data. Results of this study will be useful to select "safe" holding times of bull semen in plastic straws placed N(2)V/LN(2) to ensure that complete freezing of the sample has occurred in the nitrogen vapor and avoid cryodamage when plunging in LN(2). Freezing times predicted by the numerical model can be applied to optimize freezing protocols of bull semen in straws.

  19. SiC coatings grown by liquid injection chemical vapor deposition using single source metal-organic precursors

    OpenAIRE

    Boisselier, Guilhaume; Maury, Francis; Schuster, Frédéric

    2013-01-01

    International audience; SiC coatings have been grown by direct liquid injection of organosilanes in a hot-wall chemical vapor depositionreactor (DLICVD). 1,3-disilabutane (DSB) and polysilaethylene (PSE) were used as single-source precursors. Amorphous and stoichiometric SiC coatings were deposited under low pressure on various substrates in the temperature range of 923–1073 K. Thickness gradients due to the temperature profiles and the precursor depletion were observed along the reactor axis...

  20. Intermolecular network analysis of the liquid and vapor interfaces of pentane and water: microsolvation does not trend with interfacial properties.

    Science.gov (United States)

    Ghadar, Yasaman; Clark, Aurora E

    2014-06-28

    Liquid:vapor and liquid:liquid interfaces exhibit complex organizational structure and dynamics at the molecular level. In the case of water and organic solvents, the hydrophobicity of the organic, its conformational flexibility, and compressibility, all influence interfacial properties. This work compares the interfacial tension, width, molecular conformations and orientations at the vapor and aqueous liquid interfaces of two solvents, n-pentane and neopentane, whose varying molecular shapes can lead to significantly different interfacial behavior. Particular emphasis has been dedicated toward understanding how the hydrogen bond network of water responds to the pentane relative to the vapor interface and the sensitivity of the network to the individual pentane isomer and system temperature. Interfacial microsolvation of the immiscible solvents has been examined using graph theoretical methods that quantify the structure and dynamics of microsolvated species (both H2O in C5H12 and C5H12 in H2O). At room temperature, interfacial water at the pentane phase boundary is found to have markedly different organization and dynamics than at the vapor interface (as indicated by the hydrogen bond distributions and hydrogen bond persistence in solution). While the mesoscale interfacial properties (e.g. interfacial tension) are sensitive to the specific pentane isomer, the distribution and persistence of microsolvated species at the interface is nearly identical for both systems, irrespective of temperature (between 273 K and 298 K). This has important implications for understanding how properties defined by the interfacial organization are related to the underlying solvation reactions that drive formation of the phase boundary.

  1. Inhomogeneous Monte Carlo simulation of the vapor-liquid equilibrium of benzene between 300 K and 530 K

    OpenAIRE

    J. Janeček; Krienke, H.; Schmeer, G.

    2007-01-01

    The inhomogeneous Monte Carlo technique is used in studying the vapor-liquid interface of benzene in a broad range of temperatures using the TraPPE potential field. The obtained values of the VLE parameters are in good agreement with the experimental values as well as with the results from GEMC simulations. In contrast to the GEMC, within one simulation box the inhomogeneous MC technique also yields information on the structural properties of the interphase between the two phases. The values ...

  2. Isobaric vapor-liquid equilibria in the systems methyl 1,1-dimethylethyl ether + hexane and + heptane

    Energy Technology Data Exchange (ETDEWEB)

    Wisniak, J.; Magen, E.; Shachar, M.; Zeroni, I.; Segura, H. [Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Chemical Engineering; Reich, R. [Univ. de Concepcion (Chile). Dept. of Chemical Engineering

    1997-03-01

    The vapor-liquid equilibrium at 94 kPa has been determined for the binary systems of methyl 1,1-dimethylethyl ether (MTBE) with hexane and with heptane. Both systems deviate slightly from ideal behavior, can be described as regular solutions, and do not present an azeotrope. The activity coefficients and boiling point of the solutions were correlated with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak-Tamir equations.

  3. Isobaric Molecular Dynamics Version of the Generalized Replica Exchange Method (gREM): Liquid-Vapor Equilibrium.

    Science.gov (United States)

    Małolepsza, Edyta; Secor, Maxim; Keyes, Tom

    2015-10-22

    A prescription for sampling isobaric generalized ensembles with molecular dynamics is presented and applied to the generalized replica exchange method (gREM), which was designed to simulate first-order phase transitions. The properties of the isobaric gREM ensemble are discussed, and a study is presented for the liquid-vapor equilibrium of the guest molecules given for gas hydrate formation with the mW water model. Phase diagrams, critical parameters, and a law of corresponding states are obtained.

  4. Vapor Bubbles

    Science.gov (United States)

    Prosperetti, Andrea

    2017-01-01

    This article reviews the fundamental physics of vapor bubbles in liquids. Work on bubble growth and condensation for stationary and translating bubbles is summarized and the differences with bubbles containing a permanent gas stressed. In particular, it is shown that the natural frequency of a vapor bubble is proportional not to the inverse radius, as for a gas bubble, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the bubble with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of pressure waves in a vaporous bubbly liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and vapor bubbles in an immiscible liquid.

  5. Vapor-liquid phase behavior of the iodine-sulfur water-splitting process : LDRD final report for FY03.

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, Robert W.; Larson, Richard S.; Lutz, Andrew E.

    2004-01-01

    This report summarizes the results of a one-year LDRD project that was undertaken to better understand the equilibrium behavior of the iodine-water-hydriodic acid system at elevated temperature and pressure. We attempted to extend the phase equilibrium database for this system in order to facilitate development of the iodine-sulfur water-splitting process to produce hydrogen to a commercial scale. The iodine-sulfur cycle for thermochemical splitting of water is recognized as the most efficient such process and is particularly well suited to coupling to a high-temperature source of process heat. This study intended to combine experimental measurements of vapor-liquid-liquid equilibrium and equation-of-state modeling of equilibrium solutions using Sandia's Chernkin software. Vapor-liquid equilibrium experiments were conducted to a limited extent. The Liquid Chernkin software that was developed as part of an earlier LDRD project was enhanced and applied to model the non-ideal behavior of the liquid phases.

  6. Liquid-vapor phase relations in the Si-O system: A calorically constrained van der Waals-type model

    Science.gov (United States)

    Connolly, James A. D.

    2016-09-01

    This work explores the use of several van der Waals (vW)-type equations of state (EoS) for predicting vaporous phase relations and speciation in the Si-O system, with emphasis on the azeotropic boiling curve of SiO2-rich liquid. Comparison with the observed Rb and Hg boiling curves demonstrates that prediction accuracy is improved if the a-parameter of the EoS, which characterizes vW forces, is constrained by ambient pressure heat capacities. All EoS considered accurately reproduce metal boiling curve trajectories, but absent knowledge of the true critical compressibility factor, critical temperatures remain uncertain by ~500 K. The EoS plausibly represent the termination of the azeotropic boiling curve of silica-rich liquid by a critical point across which the dominant Si oxidation state changes abruptly from the tetravalent state characteristic of the liquid to the divalent state characteristic of the vapor. The azeotropic composition diverges from silica toward metal-rich compositions with increasing temperature. Consequently, silica boiling is divariant and atmospheric loss after a giant impact would enrich residual silicate liquids in reduced silicon. Two major sources of uncertainty in the boiling curve prediction are the heat capacity of silica liquid, which may decay during depolymerization from the near-Dulong-Petit limit heat capacity of the ionic liquid to value characteristic of the molecular liquid, and the unknown liquid affinity of silicon monoxide. Extremal scenarios for these uncertainties yield critical temperatures and compositions of 5200-6200 K and Si1.1O2-Si1.4O2. The lowest critical temperatures are marginally consistent with shock experiments and are therefore considered more probable.

  7. Vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (EVLM1111, LB5653_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (EVLM1111, LB5653_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  8. Vapor-Liquid Equilibrium in the Mixture 1-Chlorobutane C4H9Cl + C6H10O Cyclohexanone (EVLM1111, LB5637_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1-Chlorobutane C4H9Cl + C6H10O Cyclohexanone (EVLM1111, LB5637_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  9. Vapor-Liquid Equilibrium in the Mixture Cyclohexanone C6H10O + C6H12O Cyclohexanol (EVLM1111, LB5657_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Cyclohexanone C6H10O + C6H12O Cyclohexanol (EVLM1111, LB5657_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  10. Vapor-Liquid Equilibrium in the Mixture Diethyl carbonate C5H10O3 + C6H14O Hexan-1-ol (EVLM1111, LB5629_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Diethyl carbonate C5H10O3 + C6H14O Hexan-1-ol (EVLM1111, LB5629_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  11. Design of a vapor-liquid-equilibrium, surface tension, and density apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, C.D.; Outcalt, S.L. [National Institute of Standards and Technology, Boulder, CO (United States)

    1997-12-31

    The design and performance of a unique vapor-liquid equilibrium (VLE) apparatus with density and surface tension capabilities is presented. The apparatus operates at temperatures ranging from 218 to 423 K, at pressures to 17 MPa, at densities to 1100 kg/m{sup 3}, and at surface tensions ranging from 0.1 to 75 mN/m. Temperatures are measured with a precision of {+-}0.02 K, pressures with a precision of {+-}0.1% of full scale, densities with a precision of {+-}0.5 kg/m{sup 3}, surface tensions with a precision of {+-}0.2 mN/m, and compositions with a precision of {+-}0.005 mole fraction. The apparatus is designed to be both accurate and versatile. Capabilities include: (1) the ability to operate the apparatus as a bubble point pressure or an isothermal pressure-volume-temperature (PVT) apparatus, (2) the ability to measure densities and surface tensions of the coexisting phases, and (3) the ability for either trapped or capillary sampling. We can validate our VLE and density data by measuring PVT or bubble point pressures in the apparatus. The use of the apparatus for measurements of VLE, densities, and surface tensions over wide ranges of temperature and pressure is important in equation of state and transport property model development. The use of different sampling procedures allows measurement of a wider variety of fluid mixtures. VLE measurements on the alternative refrigerant system R32/134a are presented and compared to literature results to verify the performance of the apparatus.

  12. Zr基大块非晶合金在过冷液相区超塑性成形的摩擦行为及机理研究%Study on the Friction Behavior and Mechanism of Zr-based Bulk Metallic Glass Superplastic Forming in the Supercooled Liquid Region

    Institute of Scientific and Technical Information of China (English)

    郑志镇; 成蛟; 王新云; 李建军

    2009-01-01

    The friction behavior of Zr_(55) Al_(10)Ni_5Cu_(30) bulk metallic glass in the supercooled liquid region was investigated. The influence of forming temperature and velocity on friction factor was established by double cup extrusion test. The calibration curves of friction factor were evaluated by FE simulation and Kawamura's constitutive equation was adopted. Constant parameters in the constitutive equation were acquired by fitting the data from compression test. The results indicate that the friction factor of bulk metallic glass forming in the supercooled liquid region is between 0. 2 and 0. 7. With the temperature rising, the friction factor decreases in general under a low forming velocity. However, the friction factor increases slightly and then decreases abruptly under a high forming velocity. In low temperature area of supercooled liquid region, the friction factor increases abruptly with increasing of the forming velocity. While in high temperature area of supercooled liquid region, the friction factor decreases slightly with increasing of the forming velocity. The friction mechanism of bulk metallic glass forming in supercooled liquid region was analyzed by modern tribology theory. Adhesion is the dominant factor contributing to the friction of bulk metallic glass.%采用双杯挤压方法研究了成形温度、应变速率等工艺参数对Zr_(55) Al_(10) Ni_5 Cu_(30)块体非晶合金在过冷液相区塑性成形时模具和零件之间的摩擦行为的影响.采用有限元模拟方法获得大块非晶合金双杯挤压的摩擦因数标定曲线,有限元模拟中非晶合金的变形采用Kawamura的本构模型,将高温压缩实验的数据拟合,获得本构模型中的参数,结果表明非晶合金在过冷液相区内变形的摩擦因数在0.2~0.7之间.当应变速率较低时,随着温度的升高,摩擦因数总体上降低;而当应变速率较高时,随着温度的升高,摩擦因数先略有上升,然后急剧下降.当温度较低

  13. Fluctuations and Linear Response in Supercooled Liquids

    DEFF Research Database (Denmark)

    Nielsen, Johannes K.

    Fluctuation dissipation theorems are derived for thermodynamic properties like frequency dependent specific heat and compressibility. First the case where a systems dynamics are restricted by constant volume and energy is considered. The dynamic linear response to a heat pulse and a volume change...... at time zero is calculated, under assumption of energy conservation. Then the case of isothermal isobaric conditions are treated by a slight modification of ordinary linear response theory. In both cases the perturbation cannot be stated through the Hamiltonian, but has to be imposed by variation...... of the external thermodynamic system parameters. In thermodynamic response theory equivalence between ensembles is broken, but time correlation functions sampled in different ensembles are connected through the Maxwell relations of thermodynamics generalized to the frequency domain. Different applications...

  14. Decomposition mechanism in supercooled liquid alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W. L.; Loffler, J. F.; Thiyagarajan, P.

    1999-07-12

    The authors performed small-angle neutron scattering experiments on the bulk amorphous alloy Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} (Vit1{reg_sign}) and on further alloys, where the ZrTi and CuBe content have been changed, following the tie-line in the direction of Zr{sub 46.8}Ti{sub 8.2}Cu{sub 7.5}Ni{sub 10}Be{sub 27.5} (Vit4{reg_sign}). The SANS data of the samples, preannealed at temperatures between 330 C and 390 C, show interference peaks giving evidence for spatially correlated arrangements of inhomogeneities. The Q values of the interference peaks, Q{sub max}, decrease with increasing annealing temperature T{sub a} and, at a given annealing temperature, with composition following the tie-line from Vit1 to Vit4. They find that, in two distinguished regimes, the data follow a relation 1/L{sup 2} {proportional_to} T{sub a} as predicted by Cahn's theory (L = 2{pi}/Q{sub max} is the wavelength of the decomposition), with a crossover at the glass transition temperature T{sub g} = 350 C. The authors explain the crossover by different diffusion mechanisms below and above T{sub g}.

  15. Surface-Controlled Orientational Transitions in Elastically Strained Films of Liquid Crystal That Are Triggered by Vapors of Toluene.

    Science.gov (United States)

    Bedolla Pantoja, Marco A; Abbott, Nicholas L

    2016-05-25

    We report the fabrication of chemically patterned microwells that enable the rapid and facile preparation (by spin coating and patterned dewetting) of thin films of liquid crystals (LCs) that have precise thicknesses (0.7-30 μm), are supported on chemically defined substrates, and have free upper surfaces. We use these microwells to prepare elastically strained nematic LC films supported on silica glass, gold, or polystyrene substrates and thereby characterize the response of the strained LC films to vapors of toluene. We report that low concentrations of toluene vapor (LC to lower the anchoring energy of the LC on these substrates, thus allowing the elastic energy of the strained LC film to drive the LC films through an orientational transition. The central role of the toluene-induced change in surface anchoring energy is supported by additional experiments in which the response of the nematic LC to changes in film thickness and substrate identity are quantified. A simple thermodynamic model captures these trends and yielded estimates of anchoring energies (8-22 μJ/m(2)). Significantly, the orientational transitions observed in these strained LC thin films occur at concentrations of toluene vapor that are almost 1 order of magnitude below those which lead to bulk phase transitions, and they are not triggered by exposure to water vapor. Overall, these results hint at principles for the design of responsive LC-based materials that can be triggered by concentrations of aromatic, volatile organic compounds that are relevant to human health.

  16. Prediction of the enthalpies of vaporization for room-temperature ionic liquids: Correlations and a substitution-based additive scheme

    Energy Technology Data Exchange (ETDEWEB)

    Kabo, Gennady J. [Chemistry Faculty and Research Institute for Physical Chemical Problems, Belarusian State University, Leningradskaya 14, 220030 Minsk (Belarus); Paulechka, Yauheni U., E-mail: paulechka@gmail.com [Chemistry Faculty and Research Institute for Physical Chemical Problems, Belarusian State University, Leningradskaya 14, 220030 Minsk (Belarus); Zaitsau, Dzmitry H. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg. 1, 18059 Rostock (Germany); Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan (Russian Federation); Firaha, Alena S. [Chemistry Faculty and Research Institute for Physical Chemical Problems, Belarusian State University, Leningradskaya 14, 220030 Minsk (Belarus)

    2015-06-10

    Highlights: • The available literature data on Δ{sub l}{sup g}H for ionic liquids were analyzed. • Correlation equations for Δ{sub l}{sup g}H were derived using symbolic regression. • A substitution-based incremental scheme for Δ{sub l}{sup g}H was developed. • The proposed scheme has an advantage over the existing predictive procedures. - Abstract: The literature data on the enthalpies of vaporization for aprotic ionic liquids (ILs) published by the end of May 2014 were analyzed and the most reliable Δ{sub l}{sup g}H{sub m} values were derived for 68 ILs. The selected enthalpies of vaporization were correlated with density and surface tension using symbolic regression and a number of effective correlation equations were proposed. The substitution-based incremental scheme for prediction of the enthalpies of vaporization of imidazolium, pyridinium and pyrrolidinium ILs was developed. The standard error of the regression for the developed scheme is significantly lower than that for the atom-based group-contribution schemes proposed earlier.

  17. Influence of phase transition on the instability of a liquid-vapor interface in a gravitational field

    Science.gov (United States)

    Konovalov, V. V.; Lyubimov, D. V.; Lyubimova, T. P.

    2017-06-01

    This study is concerned with the linear stability of the horizontal interface between thick layers of a viscous heat-conducting liquid and its vapor in a gravitational field subject to phase transition. We consider the case when the hydrostatic base state is consistent with a balanced heat flux at the liquid-vapor interface. The corrections to the growth rate of the most dangerous perturbations and cutoff wave number, characterizing the influence of phase transition on the Rayleigh-Taylor instability, are found to be different from the data in the literature. Most of the previous results were obtained in the framework of a quasiequilibrium approximation, which had been shown to conform to the limit of thin media layers under equality of the interface temperature to a saturation temperature. The main difference from the results obtained with the quasiequilibrium approach is new values of the proportionality coefficients that correlate our corrections with the intensity of weak heating. Moreover, at large values of the heat flux rate, when deviations from the approximate linear law are important, the effect of phase transition is limited and does not exceed the size of the vapor viscosity effect.

  18. Isobaric (vapor + liquid) equilibria of 1-ethyl-3-methylimidazolium ethylsulfate plus (propionaldehyde or valeraldehyde): Experimental data and prediction

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Victor H. [School of Chemical Engineering, University of Campinas (UNICAMP), Av. Albert Einstein 500, 13083-852 Campinas, SP (Brazil); Mattedi, Silvana [Chemical Engineering Department, Polytechnic School, Federal University of Bahia (UFBA), R. Aristides Novis 2, 40210-630 Salvador, BA (Brazil); Aznar, Martin, E-mail: maznar@feq.unicamp.b [School of Chemical Engineering, University of Campinas (UNICAMP), Av. Albert Einstein 500, 13083-852 Campinas, SP (Brazil)

    2011-06-15

    Research highlights: We report density, refraction index, and VLE for (propionaldehyde or valeraldehyde) + [emim][EtSO{sub 4}]. The Peng-Robinson + Wong-Sandler + COSMO-SAC model was used to predict density and VLE. The densities were predicted with deviations below than 2.3%. The experimental VLE was predicted with deviations below than 1.6%. - Abstract: This paper reports the density, refraction index, and (vapor + liquid) equilibria (VLE) for binary systems {l_brace}aldehyde + 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO{sub 4}]){r_brace}: {l_brace}propionaldehyde + [emim][EtSO{sub 4}]{r_brace} and {l_brace}valeraldehyde + [emim][EtSO{sub 4}]{r_brace}. The uncertainties for the temperature, pressure, and compositions measurements for the phase equilibria are {+-}0.1 K, {+-}0.01 kPa and {+-}0.0004, respectively. A qualitative analysis of the variation of the properties with changes in solvent and temperature was performed. The Peng-Robinson equation of state (PR EoS), coupled with the Wong-Sandler mixing rule (WS), is used to describe the experimental data. To calculate activity coefficients we used three different models: NRTL, UNIQUAC, and COSMO-SAC. Since the predictive liquid activity coefficient model COSMO-SAC is used in the Wong-Sandler mixing rule, the resulting thermodynamic model is a completely predictive one. The prediction results for the density and for the (vapor + liquid) equilibria have a deviation lower than 2.3% and 1.6%, respectively. The (vapor + liquid) equilibria predictions show a good description for the propionaldehyde system and only a qualitative description for the valeraldehyde system.

  19. The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol

    Directory of Open Access Journals (Sweden)

    V. Soonsin

    2010-08-01

    Full Text Available We present vapor pressure data of the C2 to C5 dicarboxylic acids deduced from measured evaporation rates of single levitated particles as both, aqueous droplets and solid crystals. The data of aqueous solution particles over a wide concentration range allow us to directly calculate activities of the dicarboxylic acids and comparison of these activities with parameterizations reported in the literature. The data of the pure liquid state acids, i.e. the dicarboxylic acids in their supercooled melt state, exhibit no even-odd alternation in vapor pressure, while the acids in the solid form do. This observation is consistent with the known solubilities of the acids and our measured vapor pressures of the supercooled melt. Thus, the gas/particle partitioning of the different dicarboxylic acids in the atmosphere depends strongly on the physical state of the aerosol phase, the difference being largest for the even acids.

    Our results show also that, in general, measurements of vapor pressures of solid dicarboxylic acids may be compromised by the presence of amorphous fractions, polymorphic forms, crystalline structures with a high defect number, and/or solvent inclusions in the solid material, yielding a higher vapor pressure than the one of the thermodynamically stable crystalline form at the same temperature.

  20. The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol

    Directory of Open Access Journals (Sweden)

    V. Soonsin

    2010-12-01

    Full Text Available We present vapor pressure data of the C2 to C5 dicarboxylic acids deduced from measured evaporation rates of single levitated particles as both, aqueous droplets and solid crystals. The data of aqueous solution particles over a wide concentration range allow us to directly calculate activities of the dicarboxylic acids and comparison of these activities with parameterizations reported in the literature. The data of the pure liquid state acids, i.e. the dicarboxylic acids in their supercooled melt state, exhibit no even-odd alternation in vapor pressure, while the acids in the solid form do. This observation is consistent with the known solubilities of the acids and our measured vapor pressures of the supercooled melt. Thus, the gas/particle partitioning of the different dicarboxylic acids in the atmosphere depends strongly on the physical state of the aerosol phase, the difference being largest for the even acids. Our results show also that, in general, measurements of vapor pressures of solid dicarboxylic acids may be compromised by the presence of polymorphic forms, crystalline structures with a high defect number, and/or solvent inclusions in the solid material, yielding a higher vapor pressure than the one of the thermodynamically stable crystalline form at the same temperature.

  1. III-Vs at Scale: A PV Manufacturing Cost Analysis of the Thin Film Vapor-Liquid-Solid Growth Mode

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Maxwell; Horowitz, Kelsey; Woodhouse, Michael; Battaglia, Corsin; Kapadia, Rehan; Javey, Ali

    2016-06-01

    The authors present a manufacturing cost analysis for producing thin-film indium phosphide modules by combining a novel thin-film vapor-liquid-solid (TF-VLS) growth process with a standard monolithic module platform. The example cell structure is ITO/n-TiO2/p-InP/Mo. For a benchmark scenario of 12% efficient modules, the module cost is estimated to be $0.66/W(DC) and the module cost is calculated to be around $0.36/W(DC) at a long-term potential efficiency of 24%. The manufacturing cost for the TF-VLS growth portion is estimated to be ~$23/m2, a significant reduction compared with traditional metalorganic chemical vapor deposition. The analysis here suggests the TF-VLS growth mode could enable lower-cost, high-efficiency III-V photovoltaics compared with manufacturing methods used today and open up possibilities for other optoelectronic applications as well.

  2. Speciation analysis of mercury in cereals by liquid chromatography chemical vapor generation inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Lin, Liang-Yen; Chang, Lan-Fang; Jiang, Shiuh-Jen

    2008-08-27

    A simple and rapid procedure for the separation and determination of inorganic, methyl, and ethyl mercury compounds was described using liquid chromatography (LC) followed by vapor generation inductively coupled plasma-mass spectrometry (VG-ICP-MS). Well resolved chromatograms were obtained within 5 min by reversed-phase liquid chromatography with a C8 column as the stationary phase and a pH 4.7 solution containing 0.5% v/v 2-mercaptoethanol and 5% v/v methanol as the mobile phase. The separated mercury compounds were converted to mercury vapors by an in situ nebulizer/vapor generation system for their introduction into ICP. The concentrations of NaBH4 and HNO3 required for vapor generation were also optimized. The method was applied for the speciation of mercury in reference materials NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and also rice flour and wheat flour samples purchased locally. The accuracy of the procedure was verified by analyzing the certified reference material NRCC DOLT-3 Dogfish Liver for methyl mercury. Precision between sample replicates was better than 13% for all the determinations. The detection limits of the mercury compounds studied were in the range 0.003-0.006 ng Hg mL(-1) in the injected solutions, which correspond to 0.02-0.06 ng g(-1) in original flour samples. A microwave-assisted extraction procedure was adopted for the extraction of mercury compounds from rice flour, wheat flour, and fish samples using a mobile phase solution.

  3. Molecular dynamics study on evaporation and condensation of n-dodecane at liquid-vapor phase equilibria.

    Science.gov (United States)

    Cao, Bing-Yang; Xie, Jian-Fei; Sazhin, Sergei S

    2011-04-28

    Molecular dynamics simulations are performed to study the evaporation and condensation of n-dodecane (C(12)H(26)) at temperatures in the range 400-600 K. A modified optimized potential for liquid simulation model is applied to take into account the Lennard-Jones, bond bending and torsion potentials with the bond length constrained. The equilibrium liquid-vapor n-dodecane interface thickness is predicted to be ~1.2-2.0 nm. It is shown that the molecular chains lie preferentially parallel to the interface in the liquid-vapor transition region. The predicted evaporation/condensation coefficient decreased from 0.9 to 0.3 when temperature increased from 400 to 600 K. These values can be used for the formulation of boundary conditions in the kinetic modeling of droplet heating and evaporation processes; they are noticeably different from those predicted by the transition state theory. We also present the typical molecular behaviors in the evaporation and condensation processes. The molecular exchange in condensation, typical for simple molecules, has never been observed for n-dodecane molecular chains.

  4. Structure and dynamics of single hydrophobic/ionic heteropolymers at the vapor-liquid interface of water.

    Science.gov (United States)

    Vembanur, Srivathsan; Venkateshwaran, Vasudevan; Garde, Shekhar

    2014-04-29

    We focus on the conformational stability, structure, and dynamics of hydrophobic/charged homopolymers and heteropolymers at the vapor-liquid interface of water using extensive molecular dynamics simulations. Hydrophobic polymers collapse into globular structures in bulk water but unfold and sample a broad range of conformations at the vapor-liquid interface of water. We show that adding a pair of charges to a hydrophobic polymer at the interface can dramatically change its conformations, stabilizing hairpinlike structures, with molecular details depending on the location of the charged pair in the sequence. The translational dynamics of homopolymers and heteropolymers are also different, whereas the homopolymers skate on the interface with low drag, the tendency of charged groups to remain hydrated pulls the heteropolymers toward the liquid side of the interface, thus pinning them, increasing drag, and slowing the translational dynamics. The conformational dynamics of heteropolymers are also slower than that of the homopolymer and depend on the location of the charged groups in the sequence. Conformational dynamics are most restricted for the end-charged heteropolymer and speed up as the charge pair is moved toward the center of the sequence. We rationalize these trends using the fundamental understanding of the effects of the interface on primitive pair-level interactions between two hydrophobic groups and between oppositely charged ions in its vicinity.

  5. Measurement and Modeling of Vapor-Liquid Equilibrium for Ternary System Water+2-Propanol+1-Butyl-3-methylimidazolium Chloride

    Institute of Scientific and Technical Information of China (English)

    邓东顺; 乔玉珍; 姬登祥; 葛筠; 章连众

    2014-01-01

    Vapor-liquid equilibrium (VLE) data for water+2-propanol+1-butyl-3-methylimidazolium chloride ([bmim]Cl) were measured. Six sets of complete T, x, y data are reported, in which the 2-propanol mole fraction on IL-free basis is fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and approximate 0.98, while the IL mass fraction is varied from 0.1 to 0.8, in an interval of 0.1. The non-random-two-liquid (NRTL) and electrolyte non-random-two-liquid (eNRTL) equations are used to correlate the experimental data with satisfactory results. The ternary VLE behavior is also modeled with the parameters obtained by correlating two data sets, in which the mole fraction of 2-propanol on IL-free basis is approximately 0.1 and 0.98. In this way, the six sets of data are reproduced satisfactorily. With the eNRTL model, the root-mean-square deviation for temperature is 0.82 K and that for vapor-phase mole fraction is 0.0078. The influences of IL on activity coefficients and relative volatility of the volatile components are also graphically illustrated.

  6. Slow dynamics of supercooled water confined in nanoporous silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L [Department of Nuclear Engineering, 24-209 MIT, Cambridge, MA 02139 (United States); Faraone, A [Department of Nuclear Engineering, 24-209 MIT, Cambridge, MA 02139 (United States); Mou, C-Y [Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan (China); Yen, C-W [Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan (China); Chen, S-H [Department of Nuclear Engineering, 24-209 MIT, Cambridge, MA 02139 (United States)

    2004-11-17

    We review our incoherent quasielastic neutron scattering (QENS) studies of the dynamics of supercooled water confined in nanoporous silica materials. QENS data were analysed by using the relaxing cage model (RCM) previously developed by us. We first use molecular dynamics (MD) simulation of the extended simple point charge model (SPC/E) for bulk supercooled water to establish the validity of the RCM, which applies to both the translational and rotational motion of water molecules. We then assume that the dynamics of water molecules in the vicinity of a hydrophilic surface is similar to a bulk water at an equivalent lower supercooled temperature. This analogy was experimentally demonstrated in previous investigations of water in Vycor glasses and near hydrophilic protein surfaces. Studies were made of supercooled water in MCM-41-S (pore sizes 25, 18, and 14 A) and MCM-48-S (pore size 22 A) using three QENS spectrometers of respective energy resolutions 1, 30, and 60 {mu}eV, covering the temperature range from 325 to 200 K. Five quantities are extracted from the analysis: they are {beta}, the stretch exponent characterizing the {alpha}-relaxation; {beta}{gamma}, the exponent determining the power-law dependence of the relaxation time on Q; <{tau}{sub 0}>, the Q-independent pre-factor for the average translational relaxation time; <{tau}{sub R{sub 1}}>, the relaxation time for the first-order rotational correlation function; and <{tau}{sub R{sub 3}}>, the relaxation time for the second-order rotational correlation function. We discuss the temperature dependence of these parameters and note that, in particular, the dynamics is rapidly slowing down at temperature around 220 K, signalling the onset of a structural arrest transition of liquid water into an amorphous solid water.

  7. IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively.

    Science.gov (United States)

    Ni, Yicun; Skinner, J L

    2015-07-07

    Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm(-1) and a positive band centered at 1670 cm(-1). We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

  8. IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Yicun; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2015-07-07

    Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm{sup −1} and a positive band centered at 1670 cm{sup −1}. We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

  9. Free energy partitioning analysis of the driving forces that determine ion density profiles near the water liquid-vapor interface.

    Science.gov (United States)

    Arslanargin, Ayse; Beck, Thomas L

    2012-03-14

    Free energy partitioning analysis is employed to explore the driving forces for ions interacting with the water liquid-vapor interface using recently optimized point charge models for the ions and SPC/E water. The Na(+) and I(-) ions are examined as an example kosmotrope/chaotrope pair. The absolute hydration free energy is partitioned into cavity formation, attractive van der Waals, local electrostatic, and far-field electrostatic contributions. We first compute the bulk hydration free energy of the ions, followed by the free energy to insert the ions at the center of a water slab. Shifts of the ion free energies occur in the slab geometry consistent with the SPC/E surface potential of the water liquid-vapor interface. Then the free energy profiles are examined for ion passage from the slab center to the dividing surface. The profiles show that, for the large chaotropic I(-) ion, the relatively flat total free energy profile results from the near cancellation of several large contributions. The far-field electrostatic part of the free energy, largely due to the water liquid-vapor interface potential, has an important effect on ion distributions near the surface in the classical model. We conclude, however, that the individual forms of the local and far-field electrostatic contributions are expected to be model dependent when comparing classical and quantum results. The substantial attractive cavity free energy contribution for the larger I(-) ion suggests that there is a hydrophobic component important for chaotropic ion interactions with the interface.

  10. Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

    Science.gov (United States)

    Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao

    2008-01-01

    Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

  11. Calculation of H2O-NH3-CO2 Vapor Liquid Equilibria at High Concentration Conditions

    Institute of Scientific and Technical Information of China (English)

    魏顺安; 张红晶

    2004-01-01

    A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.

  12. ARTICLES: Vapor-Liquid Equilibrium Data of Carbon Dioxide+Methyl Propionate and Carbon Dioxide+Propyl Propionate Systems

    Science.gov (United States)

    Xu, Wei; Xie, Chuan-xin; Li, Hong-ling; Tian, Yi-ling

    2010-06-01

    High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate+carbon dioxide and propyl propionate+carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry's coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

  13. Engineering scale development of the Vapor-Liquid-Solid (VLS) process for the production of silicon carbide fibrils

    Energy Technology Data Exchange (ETDEWEB)

    Hollar, W.E. Jr. [Carborundum Co., Niagara Falls, NY (United States). Technology Div.; Mills, W.H. [BP America, Inc., Cleveland, OH (United States)

    1993-09-01

    Vapor-liquid-solid (VLS)SiC fibrils are used as reinforcement in ceramic matrix composites (CMC). A program has been completed for determining process scaleup parameters and to produce material for evaluation in a CMC. The scaleup is necessary to lower production cost and increase material availability. Scaleup parameters were evaluated in a reactor with a vertical dimension twice that of the LANL reactor. Results indicate that the scaleup will be possible. Feasibility of recycling process gas was demonstrated and the impact of postprocessing on yields determined.

  14. Determination of vapor-liquid equilibrium data in microfluidic segmented flows at elevated pressures using Raman spectroscopy.

    Science.gov (United States)

    Luther, Sebastian K; Stehle, Simon; Weihs, Kristian; Will, Stefan; Braeuer, Andreas

    2015-08-18

    A fast, noninvasive, and efficient analytical measurement strategy for the characterization of vapor-liquid equilibria (VLE) is presented, which is based on phase (state of matter) selective Raman spectroscopy in multiphase flows inside microcapillay systems (MCS). Isothermal VLE data were measured in binary and ternary mixtures composed of acetone, water, carbon dioxide or nitrogen at elevated pressures up to 10 MPa and temperatures up to 333 K. For validation, the obtained data were compared with literature data and reference measurements in a high-pressure variable volume cell. Additionally, the mixtures were investigated at temperatures and pressures where no data is available in literature to extend the high-pressure VLE database.

  15. Investigation of the liquid/vapor composition of compressed liquid CO2 with N2 and O2 in integrated pollutant removal systems for coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Oryshchyn, Danylo B.; Ochs, Thomas L.; Summers, Cathy A.; Penner, Larry R.; Gerdemann, Stephen J.

    2005-01-01

    Accurate prediction of the processes in Integrated Pollutant Removal (IPR) using compression and condensation of coal combustion products requires an understanding of the liquid/vapor ternary CO2/O2/N2 system. At conditions close to the critical point of CO2 the existing equations of state deviate from the sparse measured results available in the literature. Building on existing data and procedures, the USDOE/Albany Research Center has designed an apparatus for examining compositions in this region. The design of the apparatus and planned initial experiments are presented.

  16. Measurement and correlation of isobaric vapor-liquid equilibrium for the binary system of cyclopentane and tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Yumei Li

    2014-09-01

    Full Text Available Isobaric vapor-liquid equilibrium (VLE data for the cyclopentane and tetrahydrofuran (THF system were measured at 101.3 kPa by using an equilibrium still. Thermodynamic consistency of the experimental data was confirmed by means of the Herington method. The experimental data were correlated and calculated by the Margules, Van Laar and Wilson activity-coefficient models, respectively. The Wilson and Van Laar activity-coefficient models are better than the Margules activity-coefficient model based on the average absolute deviations of temperature and the vapor-phase composition. For the Wilson and Van Laar activity-coefficient models the average absolute deviations between the experimental and the calculated values were 0.24 K and 0.23 K for the boiling point, and 0.0040 for vapor-phase composition, respectively. These agree well with the experimental data. Therefore, it was shown that the Wilson and Van Laar activity-coefficient models satisfactorily correlate the experimental results of the cyclopentane and tetrahydrofuran system.

  17. Dynamics of hydrogen bonds in water and consequences for the unusual behaviour of supercooled water

    Indian Academy of Sciences (India)

    José Teixeira

    2008-10-01

    The dynamics of liquid water is evaluated by the coherent quasi-elastic scattering at two different momentum transfers, in order to discriminate hydrogen bond life-time from molecular dynamics. The results indicate a possible issue for the puzzle of the behaviour of supercooled water.

  18. Compressive Deformation Induced Nanocrystallization of a Supercooled Zr-Based Bulk Metallic Glass

    Institute of Scientific and Technical Information of China (English)

    GUO Xiao-Lin; SHAN De-Bin; MA Ming-Zhen; GUO Bin

    2008-01-01

    The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, compressive deformation promotes the development of nucleation and suppresses the coarsening of nanocrystallites at high ternperatures.

  19. Experimental Measurements and Correlations Isobaric Vapor-Liquid Equilibria for Water + Acetic Acid + Sec-butyl Acetate at 101.3 kPa

    Institute of Scientific and Technical Information of China (English)

    LI Ling; HE Yong; WU Yanxiang; ZOU Wenhu

    2013-01-01

    Isobaric vapor-liquid equilibrium(VLE) data for acetic acid + sec-butyl acetate and water + acetic acid + sec-butyl acetate systems were determined at 101.3 kPa using a modified Rose type.The nonideality of the vapor phase caused by the association of the acetic acid was corrected by the chemical theory and Hayden-O'Connell method.Thermodynamic consistency was tested for the binary VLE data.The experimental data were correlated successfully with the Non-Random Two Liquids (NRTL) model.The Root Mean Square Deviation (RMSD) of the ternary system was 0.0038.The saturation vapor pressure of sec-butyl acetate at 329 to 385 K was measured by means of two connected equilibrium cells.The vapor pressures of water and sec-butyl acetate were correlated with the Antoine equation.The binary interaction parameters and the ternary VLE data were obtained from this work.

  20. Vapor-liquid transitions of dipolar fluids in disordered porous media: Performance of angle-averaged potentials

    Science.gov (United States)

    Spöler, C.; Klapp, S. H. L.

    2004-11-01

    Using replica integral equations in the reference hypernetted-chain (RHNC) approximation we calculate vapor-liquid spinodals, chemical potentials, and compressibilities of fluids with angle-averaged dipolar interactions adsorbed to various disordered porous media. Comparison with previous RHNC results for systems with true angle-dependent Stockmayer (dipolar plus Lennard-Jones) interactions [C. Spöler and S. H. L. Klapp, J. Chem. Phys. 118, 3628 (2003); ibid.120, 6734 (2004)] indicate that, for a dilute hard sphere matrix, the angle-averaged fluid-fluid (ff) potential is a reasonable alternative for reduced fluid dipole moments m*2=μ2/(ɛ0σ3)⩽2.0. This range is comparable to that estimated in bulk fluids, for which RHNC results are presented as well. Finally, results for weakly polar matrices suggest that angle-averaged fluid-matrix (fm) interactions can reproduce main features observed for true dipolar (fm) interactions such as the shift of the vapor-liquid spinodals towards lower temperatures and higher densities. However, the effective attraction induced by dipolar (fm) interaction is underestimated rather than overestimated as in the case of angle-averaged ff interactions.

  1. A Modified Mixing Rule for PSRK Model and Application for the Prediction of Vapor-Liquid Equilibria of Polymer Solutions

    Institute of Scientific and Technical Information of China (English)

    李敏; 王利生; J.Gmehling

    2004-01-01

    To extend the PSRK (predictive Soave-Redlich-Kwong equation of state) model to vapor-liquid equilibria of polymer solutions, a new EOS-gE mixing rule is applied in which the term ∑xiln(b/bi) in the PSRK mixing rule for the parameter a, and the combinatorial part in the original universal functional activity coefficient (UNIFAC) model are cancelled. To take into account the free volume contribution to the excess Gibbs energy in polymer solution, a quadratic mixing rule for the cross co-volume bij with an exponent equals to 1/2 is applied [bij1/2=1/2(bi1/2+bj1/2)]. The literature reported Soave-Redlich-Kwong equation of state (SRK EOS) parameters of i3 - 2- pure polymer are employed. The PSRK model with the modified mixing rule is used to predict the vapor-liquid equilibrium (VLE) of 37 solvent-polymer systems over a large range of temperature and pressure with satisfactory results.

  2. Vapor-liquid equilibrium for mixtures of hexane and squalane at temperatures from 469.8 K to 623.3 K

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, P.C.; Thies, M.C. [Clemson Univ., SC (United States). Dept. of Chemical Engineering

    1997-03-01

    Vapor and liquid equilibrium compositions have been measured for the hexane + squalane (2,6,10,15,19,23-hexamethyltetracosane) system at (469.8, 524.3, 574.6, and 623.3) K and at pressures ranging from (5.5 to 54.8) bar. A continuous-flow apparatus was used to minimize squalane degradation and to measure the lower squalane concentrations in the vapor phase. Mixture critical pressures and compositions were also obtained.

  3. Vapor Pressure Determination of VM Using the Denunder-Liquid Chromatography-Mass Spectrometry Technique

    Science.gov (United States)

    2015-01-01

    obtained using a mass flow controller (MFC), rotameter, or critical orifice , with a vacuum source. The vacuum source, which is external to the...The generator was then integrated into the vapor pressure test system. The airstream entered the side arm of the generator and passed through the

  4. Quantitative Aging Pattern in Mouse Urine Vapor as Measured by Gas-Liquid Chromatography

    Science.gov (United States)

    Robinson, Arthur B.; Dirren, Henri; Sheets, Alan; Miquel, Jaime; Lundgren, Paul R.

    1975-01-01

    We have discovered a quantitative aging pattern in mouse urine vapor. The diagnostic power of the pattern has been found to be high. We hope that this pattern will eventually allow quantitative estimates of physiological age and some insight into the biochemistry of aging.

  5. Migration of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling

    Directory of Open Access Journals (Sweden)

    Peng Hao

    2011-01-01

    Full Text Available Abstract The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt.%, the heat flux is from 10 to 100 kW·m-2, and the initial liquid-level height is from 1.3 to 3.4 cm. The experimental results indicate that the migration ratio of carbon nanotube increases with the increase of the outside diameter or the length of carbon nanotube. For the fixed type of carbon nanotube, the migration ratio decreases with the increase of the oil concentration or the heat flux, and increases with the increase of the initial liquid-level height. The migration ratio of carbon nanotube increases with the decrease of dynamic viscosity of refrigerant or the increase of liquid phase density of refrigerant. A model for predicting the migration ratio of carbon nanotubes in the refrigerant-based nanofluid pool boiling is proposed, and the predictions agree with 92% of the experimental data within a deviation of ±20%.

  6. Migration of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling

    Science.gov (United States)

    2011-01-01

    The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt.%, the heat flux is from 10 to 100 kW·m-2, and the initial liquid-level height is from 1.3 to 3.4 cm. The experimental results indicate that the migration ratio of carbon nanotube increases with the increase of the outside diameter or the length of carbon nanotube. For the fixed type of carbon nanotube, the migration ratio decreases with the increase of the oil concentration or the heat flux, and increases with the increase of the initial liquid-level height. The migration ratio of carbon nanotube increases with the decrease of dynamic viscosity of refrigerant or the increase of liquid phase density of refrigerant. A model for predicting the migration ratio of carbon nanotubes in the refrigerant-based nanofluid pool boiling is proposed, and the predictions agree with 92% of the experimental data within a deviation of ±20%. PMID:21711730

  7. Formation and evolution characteristics of bcc phase during isothermal relaxation processes of supercooled liquid and amorphous metal Pb%过冷液态和非晶态金属Pb等温驰豫过程中bcc相的形成和演变特性

    Institute of Scientific and Technical Information of China (English)

    周丽丽; 刘让苏; 田泽安; 刘海蓉; 侯兆阳; 朱轩民; 刘全慧

    2011-01-01

    The formation and evolution characteristics of bcc phase during the isothermal relaxation processes for supercooled-liquid and amorphous Pb were investigated by molecular dynamics simulation and cluster-type index method (CTIM). It is found that during the relaxation process,the formation and evolution of bcc phase are closely dependent on the initial temperature and structure.During the simulation time scale,when the initial temperature is in the range of supercooled liquid region,the bcc phase can be formed and kept a long time; while it is in the range of glassy region,the bcc phase can be formed at first and then partially transformed into hcp phase; when it decreases to the lower one,the hcp and fcc phases can be directly transformed from the glassy structure without undergoing the metastable bcc phase. The Ostwald's "step rule" is impactful during the isothermal relaxation process of the supercooled and glassy Pb,and the metastable bcc phase plays an important role in the precursor of crystallization.%采用分子动力学模拟方法和团簇类型指数法,对过冷液态和非晶态金属Pb在等温驰豫过程中bcc相的形成和演变特性进行研究.结果表明:bcc相的形成和演变密切依赖等温驰豫过程的初始温度和初始结构,在过冷液态区,bcc相很容易形成并在模拟时间范围内保持稳定;而在非晶态区,bcc相先形成并随后部分转变为hcp相,当驰豫的初始温度在较低的153 K和113 K时,hcp和fcc相不经历亚稳bcc相而直接在非晶态结构中形成;这说明Ostwald的"步进原则"在过冷液态和非晶态Pb等温驰豫过程中是有效的,并且,亚稳bcc相起到重要的晶化前驱的作用.

  8. Experimental investigations on heat content of supercooled sodium acetate trihydrate by a simple heat loss method

    DEFF Research Database (Denmark)

    Kong, Weiqiang; Dannemand, Mark; Johansen, Jakob Berg

    2016-01-01

    Sodium acetate trihydrate is a phase change material that can be used for long term heat storage in solar heating systems because of its relatively high heat of fusion, a melting temperature of 58 °C and its ability to supercool stable. In practical applications sodium acetate trihydrate tend...... to suffer from phase separation which is the phenomenon where anhydrous salt settles to the bottom over time. This happens especially in supercooled state. The heat released from the crystallization of supercooled sodium acetate trihydrate with phase separation will be lower than the heat released from...... sodium acetate trihydrate without phase separation. Possible ways of avoiding or reducing the problem of phase separation were investigated. A wide variety of composites of sodium acetate trihydrate with additives including extra water, thickening agents, solid and liquid polymers have been...

  9. The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500°C

    Science.gov (United States)

    Bischoff, James L.; Rosenbauer, Robert J.; Fournier, Robert O.

    1996-01-01

    We determined vapor-liquid relations (P-T-x) and derived critical parameters for the system CaCl2-H2O from 380-500??C. Results show that the two-phase region of this system is extremely large and occupies a significant portion of the P-T space to which circulation of fluids in the Earth's crust is constrained. Results also show the system generates significant amounts of HCl (as much as 0.1 mol/kg) in the vapor phase buffered by the liquid at surprisingly high pressures (???230 bars at 380??C, CaCl2: CaCl2 + 2H2O = Ca(OH)2 + 2HCl. We interpret the abundance of HCl in the vapor as due to its preference for the vapor phase, and by the preference of Ca(OH)2 for either the liquid phase or solid. The recent recognition of the abundance of CaCl2 in deep brines of the Earth's crust and their hydrothermal mobilization makes the hydrolysis of CaCl2 geologically important. The boiling of Ca-rich brines produces abundant HCl buffered by the presence of the liquid at moderate pressures. The resultant Ca(OH)2 generated by this process reacts with silicates to form a variety of alteration products, such as epidote, whereas the vapor produces acid-alteration of rocks through which it ascends.

  10. Salting-out effect of ionic liquids on isobaric vapor-liquid equilibrium of acetonitrile-water system☆

    Institute of Scientific and Technical Information of China (English)

    Jing Fang; Rui Zhao; Hui Wang; Chunli Li; Jing Liu

    2015-01-01

    This paper presents the vapor–liquid equilibrium (VLE) data of acetonitrile–water system containing ionic liquids (ILs) at atmospheric pressure (101.3 kPa). Since ionic liquids dissociate into anions and cations, the VLE data for the acetonitrile+water+ILs systems are correlated by salt effect models, Furter model and improved Furter model. The overall average relative deviation of Furter model and improved Furter model is 5.43%and 4.68%, respectively. Thus the salt effect models are applicable for the correlation of IL containing systems. The salting-out effect theory can be used to explain the change of relative volatility of acetonitrile–water system.

  11. Shadowing and mask opening effects during selective-area vapor-liquid-solid growth of InP nanowires by metalorganic molecular beam epitaxy.

    Science.gov (United States)

    Kelrich, A; Calahorra, Y; Greenberg, Y; Gavrilov, A; Cohen, S; Ritter, D

    2013-11-29

    Indium phosphide nanowires were grown by metalorganic molecular beam epitaxy using the selective-area vapor-liquid-solid method. We show experimentally and theoretically that the size of the annular opening around the nanowire has a major impact on nanowire growth rate. In addition, we observed a considerable reduction of the growth rate in dense two-dimensional arrays, in agreement with a calculation of the shadowing of the scattered precursors. Due to the impact of these effects on growth, they should be considered during selective-area vapor-liquid-solid nanowire epitaxy.

  12. Thermodynamics and dynamics of supercooled water

    Science.gov (United States)

    Mazza, Marco G.

    This thesis employs methods of statistical mechanics and numerical simulations to study some aspects of the thermodynamic and dynamic behavior of liquid water. As liquid water is cooled down into the supercooled state, some regions of the sample show correlated molecular motion. Previously, only the translational motion has been the object of investigation. Given the importance of orientational dynamics for water, a question that naturally arises is whether the rotational molecular motion also shows heterogeneous dynamics. We show that the most rotationally mobile molecules tend to form clusters, "rotational heterogeneities", and we study their dependence upon observation time and temperature. Further, we show evidence that molecules belonging to dynamic heterogeneities are involved in bifurcated bonds. Since the presence of dynamic heterogeneities is increasingly important as the temperature is lowered, one would expect a signature of this phenomenon in dynamical quantities. We study the effect of dynamic heterogeneities on the origin of the breakdown of the Stokes--- Einstein and Stokes---Einstein---Debye relations for water. These relations link the diffusivity to temperature and viscosity. We study the separation of time scales of dynamic heterogeneities and the diffusive regime. We also consider different sets of mobility, slowest and fastest, for both translational and rotational heterogeneities. A long-standing problem in biology is the seemingly universal loss of biological activity of all biomolecules, a phenomenon termed the "protein glass transition". We explore the connection between the hypothesized liquid-liquid phase transition of water, and the protein glass transition. We find that the protein glass transition coincides with the crossing of the Widom line of hydration water. Many different scenarios have been proposed to rationalize water's thermodynamic anomalies. We study a tell model for water using the Wolff' cluster algorithm, which permits

  13. Structure and diffusion of nanoparticle monolayers floating at liquid/vapor interfaces: a molecular dynamics study.

    Science.gov (United States)

    Cheng, Shengfeng; Grest, Gary S

    2012-06-07

    Large-scale molecular dynamics simulations are used to simulate a layer of nanoparticles floating on the surface of a liquid. Both a low viscosity liquid, represented by Lennard-Jones monomers, and a high viscosity liquid, represented by linear homopolymers, are studied. The organization and diffusion of the nanoparticles are analyzed as the nanoparticle density and the contact angle between the nanoparticles and liquid are varied. When the interaction between the nanoparticles and liquid is reduced the contact angle increases and the nanoparticles ride higher on the liquid surface, which enables them to diffuse faster. In this case the short-range order is also reduced as seen in the pair correlation function. For the polymeric liquids, the out-of-layer fluctuation is suppressed and the short-range order is slightly enhanced. However, the diffusion becomes much slower and the mean square displacement even shows sub-linear time dependence at large times. The relation between diffusion coefficient and viscosity is found to deviate from that in bulk diffusion. Results are compared to simulations of the identical nanoparticles in 2-dimensions.

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

    Institute of Scientific and Technical Information of China (English)

    王琳; 曹丰璞; 刘珊珊; 杨浩

    2011-01-01

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

  15. Prediction of the vapor-liquid distribution constants for volatile nonelectrolytes in water up to its critical temperature

    Science.gov (United States)

    Plyasunov, Andrey V.; Shock, Everett L.

    2003-12-01

    The distribution of solutes between coexisting liquid and vapor phases of water can be expressed by the distribution constant, K D, defined as K D= limitlim x→0y/x, where y and x stand for the mole fraction concentrations of a solute in vapor and liquid phases, respectively. Research reported here is concerned with the prediction of this property, K D, for volatile nonelectrolytes, over the whole temperature range of existence of the vapor-liquid equilibrium for water, i.e. from 273 K to the critical temperature at 647.1 K. A simple empirical method is proposed to extrapolate the values of K D from 298 K to 500-550 K. Calculations at higher temperatures are based on the theoretical relation that establishes the proportionality between RTlnK D and the Krichevskii parameter, A Kr, which is the single most important property of a solute at near-critical conditions, and can be evaluated using the method proposed here. The comparison of predicted and experimental values of K D and A Kr for a few well-studied solutes reveals the satisfactory performance of the proposed method. It appears that the accuracy of predictions in the framework of this method is limited mainly by the accuracy of the values of the thermodynamic functions of hydration of solutes at 298 K, and that the best way to improve the quality of predictions of K D and A Kr is to increase the inventory of accurate calorimetric enthalpy and heat capacity data for aqueous solutes at 298 K. We stress that the values of the Krichevskii parameter, such as those generated in this study, are of crucial importance for reliable predictions of the chemical potential and its derivatives (V 2o, Cp 2o) for aqueous solutes at near-critical and supercritical conditions. Values of K D and A Kr are predicted for many inorganic volatile nonelectrolytes and some halogenated derivatives of methane and ethene. We show that both ln K D and A Kr for aqueous organic solutes follow group additivity systematics, and we derive a set

  16. Crystallization Behavior and Relaxation Dynamics of Supercooled S‑Ketoprofen and the Racemic Mixture along an Isochrone

    DEFF Research Database (Denmark)

    Adrjanowicz, Karolina; Kaminski, Kamil; Paluch, Marian

    2015-01-01

    In this paper, we study crystallization behavior and molecular dynamics in the supercooled liquid state of the pharmaceutically important compound ketoprofen at various thermodynamic conditions. Dielectric relaxation for a racemic mixture was investigated in a wide range of temperatures and press......In this paper, we study crystallization behavior and molecular dynamics in the supercooled liquid state of the pharmaceutically important compound ketoprofen at various thermodynamic conditions. Dielectric relaxation for a racemic mixture was investigated in a wide range of temperatures...... of pure enantiomers and their 50–50 equimolar mixture in the metastable supercooled liquid state. Crystallization kinetic studies revealed that at the same isochronal conditions the behavior of the S-enantiomer and R,S-racemic mixture of ketoprofen is entirely different. This was examined in the context...

  17. Correlation of retention times on liquid crystal capillary column with reported vapor pressures and half-lives of compounds used in pheromone formulations.

    Science.gov (United States)

    Heath, R R; Tumlinson, J H

    1986-11-01

    A method has been developed to determine by capillary gas chromatography on liquid crystal stationary phases the relative vapor pressures and half-lives of many compounds used as insect pheromones. This study demonstrated that the retention time of seven acetates on a liquid crystal column (cholesteryl-p-chlorocinnamate) could be correlated closely to the reported vapor pressures of the compounds. For 13 additional pheromonal acetates and alcohols, reported half-lives showed a high degree of correlation with their retention times on the liquid crystal column. Thus chromatography on capillary liquid crystal gas Chromatographie columns appears to be a useful method for determining the relative volatilities of many pheromones to facilitate the development of more precise formulations.

  18. An ab initio study of the structure and atomic transport in bulk liquid Ag and its liquid-vapor interface

    Science.gov (United States)

    del Rio, Beatriz G.; González, David J.; González, Luis E.

    2016-10-01

    Several static and dynamic properties of bulk liquid Ag at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals propagating excitations whose dispersion at long wavelengths is compatible with the experimental sound velocity. Results are also reported for other transport coefficients. Additional simulations have also been performed so as to study the structure of the free liquid surface. The calculated longitudinal ionic density profile shows an oscillatory behaviour, whose properties are analyzed through macroscopic and microscopic methods. The intrinsic X-ray reflectivity of the surface is predicted to show a layering peak associated to the interlayer distance.

  19. Vapor-Liquid Equilibrium Measurements and Modeling for Ternary System Water + Ethanol + 1-Butyl-3-methylimidazolium Acetate

    Institute of Scientific and Technical Information of China (English)

    D.ENG Dongshun; WANG Rufa; ZHANG Lianzhong; GE Yun; JI Jianbing

    2011-01-01

    Vapor-liquid equilibrium(VLE) data were measured for ternary system water + ethanol + 1-butyl-3methylimidazolium acetate([bmim][OAc]),in a relatively wide range of ionic liquid(IL) mass fractions up to 0.8.Six sets of complete T-x-y data were obtained,in which the mole fraction of ethanol on IL-free basis was fixed separately at 0.1,0.2,0.4,0.6,0.8,and approximate 0.98.The non-random-two-liquid(NRTL) and electrolyte non-random-two-liquid(eNRTL) equations were used for correlation,showing similar deviations.The ternary VLE was also modeled with the correlation from two data sets,with the mole fractions of ethanol on IL-free basis being 0.1 and approximate 0.98.The VLE data were also reproduced satisfactorily.With the eNRTL model,the root-mean-square deviation for temperature is 0.79K and that for vapor-phase mole fraction is 0.0094.The calculations are in good agreement with experimental data.The effect of the IL on the VLE behavior of the volatile components is also illustrated.

  20. MOLECULAR SIMULATION OF THE VAPOR-LIQUID EQUILIBRIUM OF N2-NC5 MIXTURE BY MONTE CARLO SIMULATIONS

    Directory of Open Access Journals (Sweden)

    Florianne Castillo-Borja

    2013-12-01

    Full Text Available ABSTRACT This study used Monte Carlo simulations in the Gibbs ensemble to describe the liquid-vapor phase equilibrium of nitrogen-n-pentane system for three isotherms. The study analyzed a wide range of pressures ranging up to 25 MPa. The system was modeled using the intermolecular potential Galassi-Tildesley for nitrogen and SKS for n-pentane. Results were compared against experimental data. Far from the critical point region, analyzed models reproduce favorably shape of the curve of phase equilibrium and in the vicinity of the critical point, results tend to move away from the experimental behavior. Critical points were determined (pressure, density and composition for the three isotherms using an extrapolation method based on scaling laws, with satisfactory results. Calculated coexistence curves are adequate even if the models analyzed do not contain optimized binary interaction parameters .

  1. A variational approach to the liquid-vapor phase transition for hardcore ions in the bulk and in nanopores

    CERN Document Server

    Loubet, Bastien; Palmeri, John

    2016-01-01

    We employ a field-theoretical variational approach to study the behavior of ionic solutions in the grand canonical ensemble. To describe properly the hardcore interactions between ions, we use a cutoff in Fourier space for the electrostatic contribution of the grand potential and the Carnahan-Starling equation of state with a modified chemical potential for the pressure one. We first calibrate our method by comparing its predictions at room temperature with Monte Carlo results for excess chemical potential and energy. We then validate our approach in the bulk phase by describing the classical "ionic liquid-vapor" phase transition induced by ionic correlations at low temperature, before applying it to electrolytes at room temperature confined to nanopores embedded in a low dielectric medium and coupled to an external reservoir of ions. The ionic concentration in the nanopore is then correctly described from very low bulk concentrations, where dielectric exclusion shifts the transition up to room temperature fo...

  2. Structural and electronic properties of InN nanowire network grown by vapor-liquid-solid method

    Energy Technology Data Exchange (ETDEWEB)

    Barick, B. K., E-mail: bkbarick@gmail.com, E-mail: subho-dh@yahoo.co.in; Dhar, S., E-mail: bkbarick@gmail.com, E-mail: subho-dh@yahoo.co.in [Department of Physics, Indian Institute of Technology, Bombay, Mumbai-400076 (India); Rodríguez-Fernández, Carlos; Cantarero, Andres [Materials Science Institute, University of Valencia, PO Box 22085, 46071 Valencia (Spain)

    2015-05-15

    Growth of InN nanowires have been carried out on quartz substrates at different temperatures by vapor-liquid-solid (VLS) technique using different thicknesses of Au catalyst layer. It has been found that a narrow window of Au layer thickness and growth temperature leads to multi-nucleation, in which each site acts as the origin of several nanowires. In this multi-nucleation regime, several tens of micrometer long wires with diameter as small as 20 nm are found to grow along [112{sup -}0] direction (a-plane) to form a dense network. Structural and electronic properties of these wires are studied. As grown nanowires show degenerate n-type behavior. Furthermore, x-ray photoemission study reveals an accumulation of electrons on the surface of these nanowires. Interestingly, the wire network shows persistence of photoconductivity for several hours after switching off the photoexcitation.

  3. Predicting the growth of S i3N4 nanowires by phase-equilibrium-dominated vapor-liquid-solid mechanism

    Science.gov (United States)

    Zhang, Yongliang; Cai, Jing; Yang, Lijun; Wu, Qiang; Wang, Xizhang; Hu, Zheng

    2017-09-01

    Nanomaterial synthesis is experiencing a profound evolution from empirical science ("cook-and-look") to prediction and design, which depends on the deep insight into the growth mechanism. Herein, we report a generalized prediction of the growth of S i3N4 nanowires by nitriding F e28S i72 alloy particles across different phase regions based on our finding of the phase-equilibrium-dominated vapor-liquid-solid (PED-VLS) mechanism. All the predictions about the growth of S i3N4 nanowires, and the associated evolutions of lattice parameters and geometries of the coexisting Fe -Si alloy phases, are experimentally confirmed quantitatively. This progress corroborates the general validity of the PED-VLS mechanism, which could be applied to the design and controllable synthesis of various one-dimensional nanomaterials.

  4. New apparatus to perform fast determinations of mixture vapor-liquid equilibria up to 10 MPa and 423 K

    Science.gov (United States)

    Laugier, S.; Richon, D.

    1986-03-01

    A new apparatus to measure vapor-liquid equilibria of mixture has been designed to work up to 10 MPa and 423 K. This apparatus makes it possible to take reproducible and representative samples and inject them directly into a chromatographic circuit {the same requirements were already satisfied by another apparatus described in a previous paper [P. Figuiére, J. F. Hom, S. Laugier, H. Renon, D. Richon, and H. Szwarc, AIChE J. 26, 872 (1980)]}. The use of the new apparatus is very simple. Comparisons with data from Kay and Albert [Ind. Eng. Chem. 48, 422 (1956)] reveal a strong similarity in the whole pressure range. Measurements in the critical region do not involve significant experimental difficulty.

  5. Theoretical evaluation of the vapor compression cycle with a liquid-line/suction-line heat exchanger, economizer, and ejector

    Energy Technology Data Exchange (ETDEWEB)

    Domanski, P.A.

    1995-03-01

    The report presents a theoretical analysis of three vapor compression cycles which are derived from the Rankine cycle by incorporating a liquid-line/suction-line heat exchanger, economizer, or ejector. These addendums to the basic cycle reduce throttling losses using different principles, and they require different mechanical hardware of different complexity and cost. The theoretical merits of the three modified cycles were evaluated in relation to the reversed Carnot and Rankine cycle. Thirty-eight fluids were included in the study using the Carnahan-Starling-DeSantis equation of state. In general, the benefit of these addendums increases with the amount of the throttling losses realized by the refrigerant in the Rankine cycle.

  6. Prediction of vapor-liquid equilibria for the alcohol + glycerol systems using UNIFAC and modified UNIFAC (Dortmund)

    Science.gov (United States)

    Hartanto, Dhoni; Mustain, Asalil; Nugroho, Febry Dwi

    2017-03-01

    The vapor-liquid equilibria for eight systems of alcohols + glycerol at 101.325 kPa have been predicted in this study using UNIFAC and Modified UNIFAC (Dortmund) group contribution methods. The investigated alcohols were methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol and 2-methyl-2-propanol. In order to study the accuracy of both contribution methods, the predicted data obtained from both approaches were compared to the experimental data from the literature. The prediction accuracy using modified UNIFAC (Dortmund) give better results compared to the UNIFAC method for (ethanol, 1-propanol, 2-propanol and 1-butanol) + glycerol but UNIFAC method show better accuracy for methanol + glycerol system. In addition, the influences of carbon chain length on the phase behaviours of alcohol + glycerol systems were also discussed as well.

  7. Reactions of Ions with Ionic Liquid Vapors by Selected-Ion Flow Tube Mass Spectrometry

    Science.gov (United States)

    2016-06-07

    spectrometric methods14 and, more recently, IR5,6 and UVvis spectroscopy.7 Indirect methods involve transpiration,8 effusion,9 or thermal gravimetric analyses... experimental mass peaks observed for EMIMþNTf2 are listed in Table 1, along with their enthalpies and free energies of reaction (at 298 K). In the cases...ion trio definitely shows the presence of neutral RTIL vapors in the flow tube. The calculated geometry of EMIMþNTf2 NH4 þ in Figure 3 shows a dramatic

  8. Comparison of molecular models of carbon monoxide for calculation of vapor-liquid equilibrium

    Directory of Open Access Journals (Sweden)

    Bibian Alonso Hoyos-Madrigal

    2015-01-01

    Full Text Available Existen varios modelos moleculares para el monóxido de carbono desarrollados a partir de diferentes mediciones experimentales. El objetivo de este trabajo es comparar los resultados que varios de estos modelos producen en el cálculo del equilibrio líquido-vapor en busca de recomendar qué modelo debe ser usado de acuerdo la propiedad y la fase que se desea calcular. Los modelos seleccionados corresponden a cuatro modelos no polares, con uno o dos sitios Lennard-Jones, y cuatro modelos polares, con dipolos o cargas parciales para representar la polaridad del monóxido de carbono. Simulaciones Monte Carlo en la versión Gibbs canónica (NVT-GEMC se emplearon para determinar las densidades de las fases en equilibrio, la presión de vapor y la entalpia de vaporización entre 80 y 130 K con cada uno de los modelos seleccionados. Se encontró que los modelos más complejos SVH, ANC y PGB, son los que mejor describen la densidad del líquido saturado (alrededor de 7% de desviación promedio, pero estos modelos generan desviaciones mayores al 40% para las propiedades del vapor y al 20% para la entalpia de vaporización. Por otro lado, el modelo no- polar BLF generó las menores desviaciones para la presión de saturación y la densidad del vapor (6.8 y 21.5%, respectivamente. Este modelo, al igual que el modelo HCB, produce desviaciones aceptables para la densidad del líquido y la entalpia de vaporización (entre 10 y 12%. Los modelos no polares BLF y HCB, que no requieren el cálculo de las interacciones de largo alcance, se pueden considerar como los modelos moleculares que presentan un balance satisfactorio entre desviaciones en los resultados y complejidad de cálculo.

  9. Liquids on-chip: direct storage and release employing micro-perforated vapor barrier films.

    Science.gov (United States)

    Czurratis, Daniel; Beyl, Yvonne; Grimm, Alexander; Brettschneider, Thomas; Zinober, Sven; Lärmer, Franz; Zengerle, Roland

    2015-07-07

    Liquids on-chip describes a reagent storage concept for disposable pressure driven Lab-on-Chip (LoC) devices, which enables liquid storage in reservoirs without additional packaging. On-chip storage of liquids can be considered as one of the major challenges for the commercial break through of polymer-based LoC devices. Especially the ability for long-term storage and reagent release on demand are the most important aspects for a fully developed technology. On-chip storage not only replaces manual pipetting, it creates numerous advantages: fully automated processing, ease of use, reduction of contamination and transportation risks. Previous concepts for on-chip storage are based on liquid packaging solutions (e.g. stick packs, blisters, glass ampoules), which implicate manufacturing complexity and additional pick and place processes. That is why we prefer on-chip storage of liquids directly in reservoirs. The liquids are collected in reservoirs, which are made of high barrier polymers or coated by selected barrier layers. Therefore, commonly used polymers for LoC applications as cyclic olefin polymer (COP) and polycarbonate (PC) were investigated in the context of novel polymer composites. To ensure long-term stability the reservoirs are sealed with a commercially available barrier film by hot embossing. The barrier film is structured by pulsed laser ablation, which installs rated break points without affecting the barrier properties. A flexible membrane is actuated through pneumatic pressure for reagent release on demand. The membrane deflection breaks the barrier film and leads to efficient cleaning of the reservoirs in order to provide the liquids for further processing.

  10. Modelling and numerical simulation of liquid-vapor phase transitions; Modelisation et simulation numerique des transitions de phase liquide-vapeur

    Energy Technology Data Exchange (ETDEWEB)

    Caro, F

    2004-11-15

    This work deals with the modelling and numerical simulation of liquid-vapor phase transition phenomena. The study is divided into two part: first we investigate phase transition phenomena with a Van Der Waals equation of state (non monotonic equation of state), then we adopt an alternative approach with two equations of state. In the first part, we study the classical viscous criteria for selecting weak solutions of the system used when the equation of state is non monotonic. Those criteria do not select physical solutions and therefore we focus a more recent criterion: the visco-capillary criterion. We use this criterion to exactly solve the Riemann problem (which imposes solving an algebraic scalar non linear equation). Unfortunately, this step is quite costly in term of CPU which prevent from using this method as a ground for building Godunov solvers. That is why we propose an alternative approach two equations of state. Using the least action principle, we propose a phase changing two-phase flow model which is based on the second thermodynamic principle. We shall then describe two equilibrium submodels issued from the relaxations processes when instantaneous equilibrium is assumed. Despite the weak hyperbolicity of the last sub-model, we propose stable numerical schemes based on a two-step strategy involving a convective step followed by a relaxation step. We show the ability of the system to simulate vapor bubbles nucleation. (author)

  11. Experimental determination of the (vapor + liquid) equilibrium data of binary mixtures of fatty acids by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matricarde Falleiro, Rafael M. [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Department of Food Engineering (DEA), School of Food Engineering, University of Campinas (UNICAMP), P.O. Box 6121, 13083-862 Campinas, SP (Brazil); Kraehenbuehl, Maria A., E-mail: mak@feq.unicamp.b [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil)

    2010-01-15

    (Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (phi = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C{sub 14:0}) + palmitic acid (C{sub 16:0}), myristic acid (C{sub 14:0}) + stearic acid (C{sub 18:0}), and palmitic acid (C{sub 16:0}) + stearic acid (C{sub 18:0}), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g{sup E} models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.

  12. Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 1. Vapor-liquid equilibria

    DEFF Research Database (Denmark)

    Grenner, Andreas; Tsivintzelis, Ioannis; Economou, Ioannis;

    2008-01-01

    for the models were taken from literature or estimated in this work. Generalized pure-component parameters were fitted to pure-component vapor-pressure and liquid-density data. For the majority of the mixtures examined, satisfactory results were obtained. For a number of mixtures, different modeling approaches...

  13. On The Validity of the Assumed PDF Method for Modeling Binary Mixing/Reaction of Evaporated Vapor in GAS/Liquid-Droplet Turbulent Shear Flow

    Science.gov (United States)

    Miller, R. S.; Bellan, J.

    1997-01-01

    An Investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is perfomed through both theroetical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer.

  14. Computation of Isobaric Vapor-Liquid Equilibrium Data for Binary and Ternary Mixtures of Methanol, Water, and Ethanoic Acid from T, p, x, and HmE Measurements

    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.

  15. A Graphical Simulation of Vapor-Liquid Equilibrium for Use as an Undergraduate Laboratory Experiment and to Demonstrate the Concept of Mathematical Modeling.

    Science.gov (United States)

    Whitman, David L.; Terry, Ronald E.

    1985-01-01

    Demonstrating petroleum engineering concepts in undergraduate laboratories often requires expensive and time-consuming experiments. To eliminate these problems, a graphical simulation technique was developed for junior-level laboratories which illustrate vapor-liquid equilibrium and the use of mathematical modeling. A description of this…

  16. Ultraviolet Photoionization Efficiency of the Vaporized Ionic Liquid 1-Butyl-3-Methylimidazolium Tricyanomethanide: Direct Detection of the Intact Ion Pair (Post Print)

    Science.gov (United States)

    2012-09-21

    ionization region, Figure 1) and the high sensitivity afforded by the synchrotron VUV light source . Thermal gravimetric analyses (TGAs) reveal that the...hour per response, including the time for reviewing instructions, searching existing data sources , gathering and maintaining the data needed, and...curve for a vaporized ionic liquid, 1- butyl-3-methylimidazolium tricyanomethanide, using tunable vacuum ultraviolet ( VUV ) photoionization time of

  17. On The Validity of the Assumed PDF Method for Modeling Binary Mixing/Reaction of Evaporated Vapor in GAS/Liquid-Droplet Turbulent Shear Flow

    Science.gov (United States)

    Miller, R. S.; Bellan, J.

    1997-01-01

    An Investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is perfomed through both theroetical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer.

  18. Vapor-Liquid Equilibrium Measurements and Modeling of the Propyl Mercaptan plus Methane plus Water System

    DEFF Research Database (Denmark)

    Awan, Javeed; Thomsen, Kaj; Coquelet, Christophe

    2010-01-01

    In this work, vapor−liquid equilibrium (VLE) measurements of propyl mercaptan (PM) in pure water were performed at three different temperatures, (303, 323, and 365) K, with a pressure variation from (1 to 8) MPa. The total system pressure was maintained by CH4. The inlet mole fraction of propyl...... mercaptan in all experiments was the same, around 4.5·10−4 in the liquid phase. The objective was to provide experimental VLE data points of the propyl mercaptan + methane + water system for modeling since there is a lack of available data. These data will allow the industrial modeling of sulfur emission...

  19. Fragile-to-strong crossover in supercooled water: A comparison between TIP4P and TIP4P/2005 models

    Science.gov (United States)

    De Marzio, M.; Camisasca, G.; Rovere, M.; Gallo, P.

    2016-05-01

    We present recent simulation results on the dynamics of supercooled water with the TIP4P/2005 potential. We find that the dynamical behaviour of the translational motion of the molecules is well interpreted in terms of the Mode Coupling Theory, as it was found for supercooled TIP4P water. We compare the results of the two models and in particular we find also in TIP4P/2005 a crossover from a fragile to a strong regime. We connect this crossover to the crossing of the Widom line emanating from the liquid-liquid critical point.

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

    DEFF Research Database (Denmark)

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

    2004-01-01

    -Redlich-Kwong equation of state. The model only requires binary, temperature-dependent interaction parameters. It has previously been used to describe the excess Gibbs energy for aqueous electrolyte mixtures and aqueous electrolyte systems containing methanol. It has been found to be an adequate model for representing...... solid-liquid-vapor equilibrium and thermal property data for strongly non-ideal systems. In this work, the model is extended to aqueous salt systems containing higher alcohols. The calculations are based on an extensive database consisting of salt solubility data, vapor liquid equilibrium data...

  1. Vapor-Liquid Equilibrium Measurements and Modeling of the Propyl Mercaptan plus Methane plus Water System

    DEFF Research Database (Denmark)

    Awan, Javeed; Thomsen, Kaj; Coquelet, Christophe;

    2010-01-01

    In this work, vapor−liquid equilibrium (VLE) measurements of propyl mercaptan (PM) in pure water were performed at three different temperatures, (303, 323, and 365) K, with a pressure variation from (1 to 8) MPa. The total system pressure was maintained by CH4. The inlet mole fraction of propyl m...

  2. Prediction of heat capacities and heats of vaporization of organic liquids by group contribution methods

    DEFF Research Database (Denmark)

    Ceriani, Roberta; Gani, Rafiqul; Meirelles, A.J.A.

    2009-01-01

    In the present work a group contribution method is proposed for the estimation of the heat capacity of organic liquids as a function of temperature for fatty compounds found in edible oil and biofuels industries. The data bank used for regression of the group contribution parameters (1395 values...

  3. Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {l_brace}1,1,1,2-tetrafluoroethane (R134a) + propane (R290){r_brace} by a recirculation apparatus with view windows

    Energy Technology Data Exchange (ETDEWEB)

    Dong Xueqiang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Gong Maoqiong, E-mail: gongmq@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Liu Junsheng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Wu Jianfeng, E-mail: jfwu@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China)

    2011-03-15

    The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than {+-}5 mK, {+-}0.0005 MPa, and {+-}0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

  4. Recovery of combustible vapors, by liquid refrigerated centrifugation, on distribution bases of loading islands; Recuperacao de vapores de combustiveis, por centrifugacao liquida refrigerada, em ilhas de carregamento das bases de distribuicao

    Energy Technology Data Exchange (ETDEWEB)

    Capulli, Domenico; Saraceno, Alessandra S.P. [Capmetal Tecnologia Ambiental, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The distribution of petroleum derivates organic combustibles represents, in volume, the second liquid fluid of the planet, with distribution basis, the loading operations of trucks, railroad coaches and vessels provokes the unfastening of volatile organic compounds - VOC, in Brazil the combustible vaporized fraction is estimated 313.308 liters daily, provoking health damages in operators and environmental impacts at aerial basin, determining the obligatory disposal of organic vapors capitation and depuration systems, with use of technologies, such as thermal oxidation, activated carbon adsorption, fluids absorptions and cryogenic condensation for treatment of the emanated vapors at loading operations, so the high aggregated value of the investment, the intensive consume of energy and the high sizes, that residue treatment units have postponed the investments in function of the missing of regularization in Brazil, counter pointing the regularization of the Clean Air Act and the United States Cost Guard that introduced the evolution and the availability of the BDT - Best Demonstrated Technologies - the technological innovation of the Hydrodynamic Precipitator operating by multi venturi liquid centrifugation married with refrigeration cycles that permit the recovery of the vapors and technologies BADCT - Best Demonstrated Control Technology - to viability the large extension of the compact control units required of smaller investment and one stage operation. (author)

  5. Boiler for generating high quality vapor

    Science.gov (United States)

    Gray, V. H.; Marto, P. J.; Joslyn, A. W.

    1972-01-01

    Boiler supplies vapor for use in turbines by imparting a high angular velocity to the liquid annulus in heated rotating drum. Drum boiler provides a sharp interface between boiling liquid and vapor, thereby, inhibiting the formation of unwanted liquid droplets.

  6. Identification of a BrOOO- intermediate species in the ozonolysis of bromide at the liquid/vapor interface from liquid jet XPS

    Science.gov (United States)

    Chen, Shuzhen; Artiglia, Luca; Orlando, Fabrizio; Corral-Arroyo, Pablo; Edebeli, Jacinta; Ammann, Markus

    2017-04-01

    Oxidation of bromide by gas phase ozone (O3) in the absence of photochemistry is believed to be one of the important dark reactions to produce HOBr as the starting point of the multiphase cycling reaction mechanisms that release bromide out of sea water, sea spray or marine aerosols from aqueous solution that later drive O3 depleting chemistry in the troposphere [1]. The reaction of bromide with O3 occurs through an acid catalyzed mechanism involving a BrOOO- complex as an intermediate [2]. Slow oxidation of bromide by O3 in the bulk aqueous phase is of limited relevance; previous kinetic experiments have suspected the reaction to be enhanced at the surface of aqueous solutions. Thus, identifying BrOOO- at the interface would be a major step to understanding the multiphase oxidation of bromide with O3. Here, we provide a direct experimental evidence for the formation of a BrOOO- reaction intermediate at the surface by investigating the reaction of aqueous solutions NaBr with gas phase O3 after millisecond time scale exposure using the surface sensitive in situ liquid jet X-ray photoelectron spectroscopy (XPS) at the Swiss Light Source (SLS). We acquired Br 3d core level spectra of 0.125 M NaBr solution in presence and absence of ozone in the gas phase. We found a new feature with a peak position shifted towards higher binding energy (by ˜0.7 eV) compared to Br-, which was clearly different from the Br 3d core levels spectra of hypobromite and bromate measured with reference solutions. Our results suggest the appearance of the formation of the BrOOO- reaction intermediate as a new component, in agreement with theoretical calculations of the Br- ozonolysis mechanism [3]. Additionally, by varying the photoelectron kinetic energy and thus probe depth via variation of the probing photon energy, the new feature appears to be present near the liquid/vapor interface. Besides, kinetic experiments for the reaction of O3 with bromide are ongoing to investigate the dependence

  7. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    Science.gov (United States)

    Campos, Reinaldo C.; Gonçalves, Rodrigo A.; Brandão, Geisamanda P.; Azevedo, Marlo S.; Oliveira, Fabiana; Wasserman, Julio

    2009-06-01

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C 18 column was used as stationary phase, and post column treatment was performed by UV irradiation (60 °C, 13 W). The eluate was then merged with 3 mol L - 1 HCl, reduction was performed by a NaBH 4 solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 µg L - 1 were obtained for ionic (Hg 2+) and HgCH 3+, for an injection volume of 200 µL. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sediments.

  8. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Reinaldo C. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil)], E-mail: rccampos@puc-rio.br; Goncalves, Rodrigo A.; Brandao, Geisamanda P.; Azevedo, Marlo S. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil); Oliveira, Fabiana; Wasserman, Julio [Institut of Geosciences, Fluminense Federal University, Av. Gal. Milton Tavares de Souza, s/n, 24.210-340, Niteroi, Rio de Janeiro (Brazil)

    2009-06-15

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C{sub 18} column was used as stationary phase, and post column treatment was performed by UV irradiation (60 deg. C, 13 W). The eluate was then merged with 3 mol L{sup -1} HCl, reduction was performed by a NaBH{sub 4} solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 {mu}g L{sup -1} were obtained for ionic (Hg{sup 2+}) and HgCH{sub 3}{sup +}, for an injection volume of 200 {mu}L. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sedi0011men.

  9. Molecular Dynamics Studies on Liquid/Vapor Interface Properties and Structures of 1-Ethyl-3-methylimidazolium Dimethylphosphate-Water.

    Science.gov (United States)

    Li, Tianyu; Zhao, Zongchang; Zhang, Xiaodong; Sun, Xican

    2017-04-13

    1-Ethyl-3-methylimidazolium dimethylphosphate ([Emim][Dmp])-water binary solution is one of the promising new working-pairs for absorption heat pump and absorption chillers, which are widely used to recover industrial waste heat. In the absorption process, the mass and heat transfer at the interface greatly depend on interface microscopic structure. Therefore, in order to understand the absorption process, it is very important to study the interface microscopic structure. The liquid-vapor interface properties, as well as the orientation of [Emim](+), [Dmp](-), water at the interface and its aqueous solution with different water mole fraction, were studied using classical all-atom force field by molecular dynamic simulations. The simulated bulk mass density fitted by hyperbolic tangent function for each system was in good agreement with the experiment data, with the relative deviation between simulated and experimental value within 2%. The simulated results indicate that anion is always distributed at the outmost layer of the interface, followed by cation and water molecule. In [Emim][Dmp], the tilt angle of imidazolium rings to the surface normal is in the range of 0° interface, but almost all ethyl intend to tilt toward gas phase and the methyl tilt toward liquid bulk compared with pure [Emim][Dmp]. Two methyl in anion prefer to turn toward gas phase and its two PO vectors toward liquid bulk. This orientation indicates that pure [Emim][Dmp] absorb water in gas phase more easily than [Emim][Dmp]+H2O system does. Water molecules are distributed in the inner layer of the interface with two OH vectors (from O atom to H atom) tilting toward external surface.

  10. Salt-assisted dispersive liquid-liquid microextraction coupled with programmed temperature vaporization gas chromatography-mass spectrometry for the determination of haloacetonitriles in drinking water.

    Science.gov (United States)

    Ma, Huilian; Li, Yun; Zhang, Haijun; Shah, Syed Mazhar; Chen, Jiping

    2014-09-01

    We report here a new analytical method for the simultaneous determination of seven haloacetonitriles (HANs) in drinking water by coupling salt-assisted dispersive liquid-liquid microextraction (SADLLME) with programmed temperature vaporizer-gas chromatography-mass spectrometry (PTV-GC-MS). The newly developed method involves the dispersion of the extractant in aqueous sample by addition of a few grams of salt and no dispersion liquid was required as compared to the traditional DLLME methods. The extractant (CH2Cl2, 50μL) and the salt (Na2SO4, 2.4g) were successively added to water (8mL) in a conical centrifuge tube that was shaken for 1min and centrifuged (3500rpm, 3min). The aliquot of sedimented phase (4μL) was then directly injected into the PTV-GC-MS system. The limits of detection and quantification for the HANs were 0.4-13.2ngL(-1) and 1.2-43.9ngL(-1), respectively. The calibration curves showed good linearity (r(2)≥0.9904) over 3 orders of magnitude. The repeatability of the method was investigated by evaluating the intra- and inter-day precisions. The relative standard deviations (RSDs) obtained were lower than 10.2% and 7.8% at low and high concentration levels. The relative recoveries ranged from 79.3% to 105.1%. The developed methodology was applied for the analysis of seven HANs in several drinking water samples in coastal and inland cities of China. It was demonstrated to be a simple, sensible, reproducible and environment friendly method for the determination of trace HANs in drinking water samples.

  11. Vapor-liquid equilibrium measurements at 101. 32 kPa for binary mixtures of methyl acetate + ethanol or 1-propanol

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J.: Susial, P.; de Alfonso, C. (Catedra de Termodinamica y Fisicoquimica, Escuela Superior de Ingeieros Industriales, 35071 Univ. of Las Palmas (ES))

    1990-07-01

    This paper reports on isobaric vapor-liquid equilibrium data at 101.32 {plus minus} 0.02 kPa for methyl acetate (1) + ethane (2) or + 1-propanol (2). The results are compared with those predicted by the UNIFAC and ASOG methods. The methyl acetate (1) + ethanol (2) system forms an azeotrope at 329.8 K and a molar concentration of x{sub 1} = 0.958. Both methods predict the vapor-phase compositions equally well, with overall mean errors of less than 5%.

  12. Dynamics of shock wave propagation and interphase process in liquid-vapor medium

    Energy Technology Data Exchange (ETDEWEB)

    Pokusaev, B.G. [Moscow State Academy of Chemical Mechanical Engineering (Russian Federation); Pribaturin, N.A. [Institute of Thermophysics, Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation)

    1995-09-01

    This paper considers the experimental results and physical effects on the pressure wave dynamics of a vapour-liquid two-phase medium of bubble and slug structure. The role of destruction and collapse of bubbles and slugs, phase transition (condensation and evaporation) on pressure wave dynamics is also studied. The general mechanisms of the wave formation, behavior and instability of a vapour-liquid structure under pressure waves, basic peculiarities of the interface heat transfer are obtained. In the experiments it has been shown that for the bubble medium the shock wave can be transformed into the powerful pressure pulse with an amplitude greater then the amplitude of the initial pressure wave. For the slug medium a characteristic structure of the amplificated wave is {open_quotes}comb{close_quotes} - like wave. It has been shown that the wave amplification caused by generation of secondary waves in a medium caused by destruction and collapse of bubbles and slugs. The obtained results can be useful at transient and emergency operational regimes of nuclear reactors, fuel tank, pipelines with two-phase flows and for development of safety models for chemical industry.

  13. Dynamics of deeply supercooled interfacial water.

    Science.gov (United States)

    Swenson, Jan; Cerveny, Silvina

    2015-01-28

    In this review we discuss the relaxation dynamics of glassy and deeply supercooled water in different types of systems. We compare the dynamics of such interfacial water in ordinary aqueous solutions, hard confinements and biological soft materials. In all these types of systems the dielectric relaxation time of the main water process exhibits a dynamic crossover from a high-temperature non-Arrhenius temperature dependence to a low-temperature Arrhenius behavior. Moreover, at large enough water content the low-temperature process is universal and exhibits the same temperature behavior in all types of systems. However, the physical nature of the dynamic crossover is somewhat different for the different types of systems. In ordinary aqueous solutions it is not even a proper dynamic crossover, since the water relaxation decouples from the cooperative α-relaxation of the solution slightly above the glass transition in the same way as all secondary (β) relaxations of glass-forming materials. In hard confinements, the physical origin of the dynamic crossover is not fully clear, but it seems to occur when the cooperative main relaxation of water at high temperatures reaches a temperature where the volume required for its cooperative motion exceeds the size of the geometrically-confined water cluster. Due to this confinement effect the α-like main relaxation of the confined water seems to transform to a more local β-relaxation with decreasing temperature. Since this low-temperature β-relaxation is universal for all systems at high water content it is possible that it can be considered as an intrinsic β-relaxation of supercooled water, including supercooled bulk water. This possibility, together with other findings for deeply supercooled interfacial water, suggests that the most accepted relaxation scenarios for supercooled bulk water have to be altered.

  14. Electron drift velocities and electron mobilities in fast room-temperature dielectric liquids and their corresponding vapors

    Science.gov (United States)

    Faidas, H.; Christophorou, L. G.; McCorkle, D. L.; Carter, J. G.

    1990-09-01

    The drift velocity, w, of excess electrons as a function of the applied uniform electric field, E, in liquid tetramethylsilane (TMS), 2,2,4,4-tetramethylpentane (TMP), tetramethyltin (TMT), and in mixtures of TMS with TMP (molar ratio, M = 1.31/1) and n-pentane ( M = 102/1; 17/1; 5.6/1) has been measured up to E-values of ˜ 10 5 V cm -1 or density ( N)-reduced ele ctric held E/ N-values of ˜ 3 × 10 -17 V cm 2. The maximum w attained for these liquids, and the corresponding values of E are: 7.2 × 10 6 cm s -1 at 125 kV cm -1 for TMS, 6.0 × 10 6 cm s -1 at 75 kV cm -1 for TMS, 2.6 × 10 6 cm s -1 at 115 kV cm -1 for TMP, 3.2 × 10 6 cm s -1 at 105 kV cm -1 for TMS/TMP ( M = 1.31/1), 6.8 × 10 6 cm s -1 at 105 kV cm -1 for TMS/n-pentane ( M = 102/1), 6.8 × 10 6 cm s -1 at 145 kV cm -1 for TMS/n-pentane ( M = 17/1), and 4.9 × 10 6 cm s -1 at 145 kV cm -1 for TMS/n-pentane ( M = 5.6/1). The thermal-electron mobilities in the above liquid media are respectively 119.3, 85.7, 31.8, 39.1, 118, 85, and 47.6 cm 2 s -1 V -1. Also, w was measured as a function of E/ N for TMS, TMP, and neopentane vapors at room temperature and is compared with that in the corresponding liquids. Properties of these media which make them desirable for radiation detectors are discussed.

  15. Solidification of supercooled water in the vicinity of a solid wall

    Science.gov (United States)

    Schremb, Markus; Tropea, Cameron

    2016-11-01

    An experimental approach utilizing a Hele-Shaw cell for the investigation of the solidification of a supercooled liquid in contact with a solid wall is presented. The setup is based on an idea presented by Marín et al. [A. G. Marín et al., Phys. Rev. Lett. 113, 054301 (2014), 10.1103/PhysRevLett.113.054301], who investigated the planar freezing of a sessile drop without supercooling. This apparatus overcomes optical distortions present when observing the freezing of sessile drops, arising due to reflections and refraction of light on the drop surface. The facility is used to investigate the freezing process of water drops, supercooled down to -20∘C , and to qualitatively demonstrate that the growth behavior is uninfluenced by the use of the Hele-Shaw cell. Different features during freezing, which are known for sessile water drops, are also observed with the Hele-Shaw cell. The growth morphology within the first phase of solidification is categorized according to the initial drop supercooling. Furthermore, freezing velocities within this phase are related to data available in the literature for the growth of single ice dendrites.

  16. Multi-component vapor-liquid equilibrium model for LES and application to ECN Spray A

    CERN Document Server

    Matheis, Jan

    2016-01-01

    We present and evaluate a detailed multi-species two-phase thermodynamic equilibrium model for large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model can represent the coexistence of supercritical states and multi-component subcritical two-phase states. LES results for the transcritical Spray A of the Engine Combustion Network (ECN) are found to agree very well to available experimental data. We also address well-known numerical challenges of trans- and supercritical fluid mixing and compare a fully conservative formulation to a quasi conservative formulation of the governing equations. Our results prove physical and numerical consistency of both methods on fine grids and demonstrate the effects of energy conservation errors associated with the quasi conservative formulation on typical LES grids.

  17. Metastable Demixing of Supercooled Cu-Co and Cu-Fe Alloys in an Oxide Flux

    Science.gov (United States)

    Li, D.; Robinson, M. B.; Rathz, T. J.; Williams, G.

    1998-01-01

    A systematic study on the liquid separation in supercooled Cu-Co and Cu-Fe alloys was performed using a melt fluxing which permits high supercooling to be achieved. Moreover, this method renders it possible to directly measure binodal temperatures and establish metastable liquid miscibility gap (LMG). All phase-separated samples at compositions ranging from 10 to 80 wt pct Co or to 83 wt pct Fe were found to exhibit droplet-shaped morphologies, in spite of various droplet distributions. Uniformly dispersed microstructures were obtained as the minority component was less than 20 vol.%; while beyond this percentage, serious coarsening was brought about. Calculations of the miscibility gap in the Cu-Co system and Stokes movement velocity of Co and Fe droplets in Cu matrix were made to analyze the experimental results.

  18. Ultra-trace determination of gold nanoparticles in environmental water by surfactant assisted dispersive liquid liquid microextraction coupled with electrothermal vaporization-inductively coupled plasma-mass spectrometry

    Science.gov (United States)

    Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

    2016-08-01

    A new method by coupling surfactant assisted dispersive liquid liquid microextraction (SA-DLLME) with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was proposed for the analysis of gold nanoparticles (AuNPs) in environmental water samples. Effective separation of AuNPs from ionic gold species was achieved by using sodium thiosulphate as a complexing agent. Various experimental parameters affecting SA-DLLME of AuNPs, such as the organic solvent, organic solvent volume, pH of the sample, the kind of surfactant, surfactant concentration, vortex time, speed of centrifugation, centrifugation time, and different coating as well as sizes of AuNPs were investigated carefully. Furthermore, the interference of coexisting ions, dissolved organic matter (DOM) and other metal nanoparticles (NPs) were studied. Under the optimal conditions, a detection limit of 2.2 ng L- 1 and an enrichment factor of 152-fold was achieved for AuNPs, and the original morphology of the AuNPs could be maintained during the extraction process. The developed method was successfully applied for the analysis of AuNPs in environmental water samples, including tap water, the East Lake water, and the Yangtze River water, with recoveries in the range of 89.6-102%. Compared with the established methods for metal NPs analysis, the proposed method has the merits of simple and fast operation, low detection limit, high selectivity, good tolerance to the sample matrix and no digestion or dilution required. It provides an efficient quantification methodology for monitoring AuNPs' pollution in the environmental water and evaluating its toxicity.

  19. Riemannian geometry study of vapor-liquid phase equilibria and supercritical behavior of the Lennard-Jones fluid.

    Science.gov (United States)

    May, Helge-Otmar; Mausbach, Peter

    2012-03-01

    The behavior of thermodynamic response functions and the thermodynamic scalar curvature in the supercritical region have been studied for a Lennard-Jones fluid based on a revised modified Benedict-Webb-Rubin equation of state. Response function extrema are sometimes used to estimate the Widom line, which is characterized by the maxima of the correlation lengths. We calculated the Widom line for the Lennard-Jones fluid without using any response function extrema. Since the volume of the correlation length is proportional to the Riemannian thermodynamic scalar curvature, the locus of the Widom line follows the slope of maximum curvature. We show that the slope of the Widom line follows the slope of the isobaric heat capacity maximum only in the close vicinity of the critical point and that, therefore, the use of response function extrema in this context is problematic. Furthermore, we constructed the vapor-liquid coexistence line for the Lennard-Jones fluid using the fact that the correlation length, and therefore the thermodynamic scalar curvature, must be equal in the two coexisting phases. We compared the resulting phase envelope with those from simulation data where multiple histogram reweighting was used and found striking agreement between the two methods.

  20. Structure and energetics of model amphiphilic molecules at the water liquid-vapor interface - A molecular dynamics study

    Science.gov (United States)

    Pohorille, Andrew; Benjamin, Ilan

    1993-01-01

    A molecular dynamics study of adsorption of p-n-pentylphenol at infinite dilution at the water liquid-vapor interface is reported. The calculated free energy of adsorption is -8.8 +/- 0.7 kcal/mol, in good agreement with the experimental value of -7.3 kcal/mol. The transition between the interfacial region and the bulk solution is sharp and well-defined by energetic, conformational, and orientational criteria. At the water surface, the phenol head group is mostly immersed in aqueous solvent. The most frequent orientation of the hydrocarbon tail is parallel to the interface, due to dispersion interactions with the water surface. This arrangement of the phenol ring and the alkyl chain requires that the chain exhibits a kink. As the polar head group is being moved into the solvent, the chain length increases and the tail becomes increasingly aligned toward the surface normal, such that the nonpolar part of the molecule exposed to water is minimized. The same effect was achieved when phenol was replaced by a more polar head group, phenolate.

  1. Essential role of catalysts (Mn, Au, and Sn) in the vapor liquid solid growth kinematics of ZnS nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, S.; Shehzad, M. A.; Hafeez, M.; Bhatti, A. S., E-mail: asbhatti@comsats.edu.pk [Center for Micro and Nano Devices (CMND), Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

    2014-01-14

    In this paper, we demonstrate that surface energy of the catalyst is a vital parameter for the growth rate, self doping of the self assembled nanowires synthesized by employing vapor liquid solid growth technique. The synthesis of ZnS nanowires was done by selectively using three different catalysts (Mn, Au, and Sn), where Au, is the most common catalyst, was used as a reference. The distinctive difference in the growth rate was due to the surface energy of the metal alloy droplet and the interface energies, as explained theoretically using thermodynamic approach. We have found that the activation energy of diffusion of (Zn, S) species in the catalyst droplet was low in Sn (0.41 eV for Zn and 0.13 eV for S) and high in Mn (1.79 eV for Zn and 0.61 eV for S) compared to Au (0.62 eV for Zn and 0.21 eV for S) catalyzed ZnS nanostructures. The thermodynamic calculations predicted the growth rates of Sn (7.5 nm/s) catalyzed nanowires was faster than Au (5.1 nm/s) and Mn (4.6 nm/s) catalyzed ZnS nanostructures, which were in agreement with the experimental results. Finally, the location of the catalyst as dopant in the grown nanostructure was predicted and compared with experimental observations.

  2. A variational approach to the liquid-vapor phase transition for hardcore ions in the bulk and in nanopores

    Science.gov (United States)

    Loubet, Bastien; Manghi, Manoel; Palmeri, John

    2016-07-01

    We employ a field-theoretical variational approach to study the behavior of ionic solutions in the grand canonical ensemble. To describe properly the hardcore interactions between ions, we use a cutoff in Fourier space for the electrostatic contribution of the grand potential and the Carnahan-Starling equation of state with a modified chemical potential for the pressure one. We first calibrate our method by comparing its predictions at room temperature with Monte Carlo results for excess chemical potential and energy. We then validate our approach in the bulk phase by describing the classical "ionic liquid-vapor" phase transition induced by ionic correlations at low temperature, before applying it to electrolytes at room temperature confined to nanopores embedded in a low dielectric medium and coupled to an external reservoir of ions. The ionic concentration in the nanopore is then correctly described from very low bulk concentrations, where dielectric exclusion shifts the transition up to room temperature for sufficiently tight nanopores, to high concentrations where hardcore interactions dominate which, as expected, modify only slightly this ionic "capillary evaporation."

  3. Structure and energetics of model amphiphilic molecules at the water liquid-vapor interface - A molecular dynamics study

    Science.gov (United States)

    Pohorille, Andrew; Benjamin, Ilan

    1993-01-01

    A molecular dynamics study of adsorption of p-n-pentylphenol at infinite dilution at the water liquid-vapor interface is reported. The calculated free energy of adsorption is -8.8 +/- 0.7 kcal/mol, in good agreement with the experimental value of -7.3 kcal/mol. The transition between the interfacial region and the bulk solution is sharp and well-defined by energetic, conformational, and orientational criteria. At the water surface, the phenol head group is mostly immersed in aqueous solvent. The most frequent orientation of the hydrocarbon tail is parallel to the interface, due to dispersion interactions with the water surface. This arrangement of the phenol ring and the alkyl chain requires that the chain exhibits a kink. As the polar head group is being moved into the solvent, the chain length increases and the tail becomes increasingly aligned toward the surface normal, such that the nonpolar part of the molecule exposed to water is minimized. The same effect was achieved when phenol was replaced by a more polar head group, phenolate.

  4. Epitaxy-enabled vapor-liquid-solid growth of tin-doped indium oxide nanowires with controlled orientations

    KAUST Repository

    Shen, Youde

    2014-08-13

    Controlling the morphology of nanowires in bottom-up synthesis and assembling them on planar substrates is of tremendous importance for device applications in electronics, photonics, sensing and energy conversion. To date, however, there remain challenges in reliably achieving these goals of orientation-controlled nanowire synthesis and assembly. Here we report that growth of planar, vertical and randomly oriented tin-doped indium oxide (ITO) nanowires can be realized on yttria-stabilized zirconia (YSZ) substrates via the epitaxy-assisted vapor-liquid-solid (VLS) mechanism, by simply regulating the growth conditions, in particular the growth temperature. This robust control on nanowire orientation is facilitated by the small lattice mismatch of 1.6% between ITO and YSZ. Further control of the orientation, symmetry and shape of the nanowires can be achieved by using YSZ substrates with (110) and (111), in addition to (100) surfaces. Based on these insights, we succeed in growing regular arrays of planar ITO nanowires from patterned catalyst nanoparticles. Overall, our discovery of unprecedented orientation control in ITO nanowires advances the general VLS synthesis, providing a robust epitaxy-based approach toward rational synthesis of nanowires. © 2014 American Chemical Society.

  5. Evaluation of Mercury in Environmental Samples by a Supramolecular SolventBased Dispersive LiquidLiquid Microextraction Method Before Analysis by a Cold Vapor Generation Technique.

    Science.gov (United States)

    Ali, Jamshed; Tuzen, Mustafa; Kazi, Tasneem G

    2017-02-01

    Supramolecular solvent–based dispersive liquid–liquid microextraction was used as a preconcentration method for the determination of trace levels of Hg. This simple method accurately measured oxidized HgII content in claystone and sandstone samples obtained from the Thar Coalfield in Pakistan. Cold vapor atomic absorption spectrometry was used as the detection technique because it is reliable and accurate. The HgII in acidic media forms a complex with dithizone (DTz) in the presence of supramolecular solvent (tetrahydrofuran and 1-undecanol), forming reverse micelles. Formation of the Hg-DTz complex was achieved to increase the interactions with the supramolecular solvent phase at pH 2.5 under the optimized experimental conditions. After addition of the supramolecular solvent to the aqueous solution, the micelles were uniformly mixed using a vortex mixer. The cloudy solution was centrifuged, and the Hg-DTz complex was extracted into the supramolecular solvent phase. Under optimized experimental conditions, the LOD and enrichment factor were found to be 5.61 ng/L and 77.8, respectively. Accuracy of the developed method was checked with Certified Reference Materials. The developed method was successfully applied for the determination of HgII in claystone and sandstone samples from the Block VII and Block VIII areas of the Thar Coalfield on the basis of depth.

  6. (Vapor + Liquid) Equilibrium (VLE) for Binary Lead-Antimony System in Vacuum Distillation: New Data and Modeling Using Nonrandom Two-Liquid (NRTL) Model

    Science.gov (United States)

    Xu, Junjie; Kong, Lingxin; Xu, Baoqiang; Yang, Bin; You, Yanjun; Xu, Shuai; Zhou, Yuezhen; Li, Yifu; Liu, Dachun

    2016-09-01

    In this work, new experimental vapor-liquid equilibrium (VLE) data of lead-antimony alloy (Pb-Sb alloy) in vacuum distillation are reported. The activity coefficients of components of Pb-Sb alloy were calculated by using the NRTL model. The calculated average relative deviations were ±0.1425 and ±0.2433 pct, and the average standard deviations were ±0.0009 and ±0.0007, respectively, for Pb and Sb. The VLE phase diagrams, such as the temperature composition ( T- x) and pressure composition ( P-x) diagrams of Pb-Sb alloy in vacuum distillation were predicted based on the NRTL model and VLE theory. The predicted results are consistent with the new experimental data indicating that VLE phase diagrams obtained by this method are reliable. The VLE phase diagrams of alloys will provide an effective and intuitive way for the technical design and realization of recycling and separation processes. The VLE data may be used in separation processes design, and the thermodynamic properties as the key parameters in specific applications.

  7. Evaluation of (vapor + liquid) equilibria for the binary systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol compositions

    Energy Technology Data Exchange (ETDEWEB)

    Ovejero, Gabriel [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de C. Quimicas, Universidsad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)], E-mail: govejero@quim.ucm.es; Dolores Romero, M.; Diez, Eduardo; Lopes, Tania; Diaz, Ismael [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de C. Quimicas, Universidsad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

    2008-11-15

    Isobaric (vapor + liquid) equilibrium at p = 101.32 kPa of pressure has been determined for the systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol mole fractions. These data were satisfactorily correlated, using ASPEN PLUS commercial software, with Wilson, NRTL, and UNIQUAC activity coefficient models to obtain the binary interaction parameters of both mixtures. Also, UNIFAC group contribution method was employed to predict the equilibrium of both mixtures. With regression values an accurate knowledge of (vapor + liquid) equilibrium for both mixtures can be reached in a range of 1-octanol mole fractions less than 0.1. UNIFAC method provides acceptable results for (1-octanol + n-hexane) system but not for (1-octanol + cyclohexane) system.

  8. Extension of LCVM-type mixing rule to three-parameter equations of state for vapor-liquid equilibria of mixtures

    Institute of Scientific and Technical Information of China (English)

    HAN Xiao-hong; CHEN Guang-ming; WANG Qin; CUI Xiao-long

    2005-01-01

    In this paper, the LCVM mixing rule is extended to the multi-parameter equations of state by combining infinite-pressure and zero-pressure mixing rule models. The new LCVM-type mixing rule, coupled with Patel-Teja equation of state(EOS) is applied for vapor-liquid equilibria of different polar and non-polar systems in which the NRTL activity coefficient model is used to calculate the excess Gibbs free energy. The tested results agree well with existing experimental data within a wide range of temperatures and pressures. In comparison with the Van der Waals mixing rule, the new mixing rule gives much better correlations for the vapor-liquid equilibria of non-polar and polar systems.

  9. Evaporation temperature-tuned physical vapor deposition growth engineering of one-dimensional non-Fermi liquid tetrathiofulvalene tetracyanoquinodimethane thin films

    DEFF Research Database (Denmark)

    Sarkar, I.; Laux, M.; Demokritova, J.

    2010-01-01

    We describe the growth of high quality tetrathiofulvalene tetracyanoquinodimethane (TTF-TCNQ) organic charge-transfer thin films which show a clear non-Fermi liquid behavior. Temperature dependent angle resolved photoemission spectroscopy and electronic structure calculations show that the growth...... of TTF-TCNQ films is accompanied by the unfavorable presence of neutral TTF and TCNQ molecules. The quality of the films can be controlled by tuning the evaporation temperature of the precursor in physical vapor deposition method....

  10. Vapor-liquid equilibria for the binary systems of 1-butanol with some halohydrocarbons at 40.0 and 101.3 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Artigas, H.; Lafuente, C.; Cea, P.; Royo, F.M.; Urieta, J.S. [Univ. de Zaragoza (Spain)

    1997-01-01

    Isobaric vapor-liquid equilibrium measurements at 40.0 and 101.3 kPa are reported for 1-butanol + chlorocyclohexane, + chlorobenzene, + bromocyclohexane, + bromobenzene. Some of the studied systems show minimum temperature azeotropes. The experimental data were tested for thermodynamic consistency and satisfactorily correlated with the Margules, Van Laar, Wilson, NRTL, and UNIQUAC equations. Predictions with the UNIFAC method and ASOG method were also obtained.

  11. Liquid-vapor phase diagram and surface properties in oppositely charged colloids represented by a mixture of attractive and repulsive Yukawa potentials.

    Science.gov (United States)

    Chapela, Gustavo A; del Río, Fernando; Alejandre, José

    2013-02-07

    The liquid-vapor phase diagrams of equal size diameter σ binary mixtures of screened potentials have been reported for several ranges of interaction using Monte Carlo simulation methods [J. B. Caballero, A. M. Puertas, A. Ferńandez-Barbero, F. J. de las Nieves, J. M. Romero-Enrique, and L. F. Rull, J. Chem. Phys. 124, 054909 (2006); A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006)]. Both works report controversial results about the stability of the phase diagram with the inverse Debye screening length κ. Caballero found stability for values of κσ up to 20 while Fortini reported stability for κσ up to 20 while Fortini reported stability for κσ ≤ 4. In this work a spinodal decomposition process where the liquid and vapor phases coexist through an interface in a slab geometry is used to obtain the phase equilibrium and surface properties using a discontinuous molecular dynamics simulations for mixtures of equal size particles carrying opposite charge and interacting with a mixture of attractive and repulsive Yukawa potentials at different values of κσ. An crude estimation of the triple point temperatures is also reported. The isothermal-isobaric method was also used to determine the phase stability using one phase simulations. We found that liquid-vapor coexistence is stable for values of κσ > 20 and that the critical temperatures have a maximum value at around κσ = 10, in agreement with Caballero et al. calculations. There also exists a controversy about the liquid-vapor envelope stability of the pure component attractive Yukawa model which is also discussed in the text. In addition, details about the equivalence between continuous and discontinuous molecular dynamics simulations are given, in the Appendix, for Yukawa and Lennard-Jones potentials.

  12. Fugacity of H2O from 0° to 350°C at the liquid-vapor equilibrium and at 1 atmosphere

    Science.gov (United States)

    Hass, John L.

    1970-01-01

    The fugacity and fugacity coefficient of H2O at the liquid-vapor equilibrium, the fugacity and the Gibbs free energy of formation of H2O at 1 atm (1.01325 bars) total pressure have been calculated from published data on the physical and thermodynamic properties of H2O and are presented at ten-degree intervals from 0° to 350°C.

  13. (Vapor + liquid) equilibria for the {l_brace}water + poly(ethylene glycol diacetyl ether) (PEGDAE) and methanol + PEGDAE{r_brace} systems

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Doo-hwan [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, SAN 56-1, Shilim-Dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Lee, Joonwoo [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, SAN 56-1, Shilim-Dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Im, Jihoon [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, SAN 56-1, Shilim-Dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, SAN 56-1, Shilim-Dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of)]. E-mail: hwayongk@snu.ac.kr

    2007-03-15

    We measured binary (vapor + liquid) equilibrium data for the {l_brace}water + poly(ethylene glycol diacetyl ether) (PEGDAE) and methanol + PEGDAE{r_brace} systems at pressures up to 400 kPa and temperatures from 333 K to 393 K. A static apparatus was used in this study. The measured data were correlated by the Peng-Robinson equation of state using the Wong-Sandler mixing rules with NRTL as the excess Gibbs free energy model.

  14. Liquid-vapor phase diagram and surface properties in oppositely charged colloids represented by a mixture of attractive and repulsive Yukawa potentials

    Science.gov (United States)

    Chapela, Gustavo A.; del Río, Fernando; Alejandre, José

    2013-02-01

    The liquid-vapor phase diagrams of equal size diameter σ binary mixtures of screened potentials have been reported for several ranges of interaction using Monte Carlo simulation methods [J. B. Caballero, A. M. Puertas, A. Ferńandez-Barbero, F. J. de las Nieves, J. M. Romero-Enrique, and L. F. Rull, J. Chem. Phys. 124, 054909 (2006), 10.1063/1.2159481; A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006), 10.1063/1.2335453]. Both works report controversial results about the stability of the phase diagram with the inverse Debye screening length κ. Caballero found stability for values of κσ up to 20 while Fortini reported stability for κσ up to 20 while Fortini reported stability for κσ ⩽ 4. In this work a spinodal decomposition process where the liquid and vapor phases coexist through an interface in a slab geometry is used to obtain the phase equilibrium and surface properties using a discontinuous molecular dynamics simulations for mixtures of equal size particles carrying opposite charge and interacting with a mixture of attractive and repulsive Yukawa potentials at different values of κσ. An crude estimation of the triple point temperatures is also reported. The isothermal-isobaric method was also used to determine the phase stability using one phase simulations. We found that liquid-vapor coexistence is stable for values of κσ > 20 and that the critical temperatures have a maximum value at around κσ = 10, in agreement with Caballero et al. calculations. There also exists a controversy about the liquid-vapor envelope stability of the pure component attractive Yukawa model which is also discussed in the text. In addition, details about the equivalence between continuous and discontinuous molecular dynamics simulations are given, in the Appendix, for Yukawa and Lennard-Jones potentials.

  15. Modeling of (vapor + liquid) equilibrium and enthalpy of solution of carbon dioxide (CO{sub 2}) in aqueous methyldiethanolamine (MDEA) solutions

    Energy Technology Data Exchange (ETDEWEB)

    Arcis, Hugues; Rodier, Laurence; Ballerat-Busserolles, Karine [Thermodynamique et Interactions Moleculaires, FRE3099, Universite Blaise Pascal Clermont-Ferrand, CNRS, 24 av. des Landais, 63177 Aubiere (France); Coxam, Jean-Yves [Thermodynamique et Interactions Moleculaires, FRE3099, Universite Blaise Pascal Clermont-Ferrand, CNRS, 24 av. des Landais, 63177 Aubiere (France)], E-mail: j-yves.coxam@univ-bpclermont.fr

    2009-06-15

    A thermodynamic model was used to estimate enthalpy of solution of carbon dioxide (CO{sub 2}) in methyldiethanolamine (MDEA) aqueous solutions. The model was based on a set of equations for chemical equilibria, phase equilibria, charge, and mass balances. Non-ideality in the liquid phase was taken into account by interaction parameters fitted to (vapor + liquid) equilibrium data. The enthalpies of solution of CO{sub 2} were derived from the model using classical thermodynamic relations and were compared to experimental values obtained in previous works.

  16. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11-C192

    Science.gov (United States)

    Acree, William; Chickos, James S.

    2017-03-01

    The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11-C192 reported over the period 1880-2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid-solid transitions or behave anisotropically in the liquid state.

  17. Molecular Simulations of the Vapor-Liquid Phase Interfaces of Pure Water Modeled with the SPC/E and the TIP4P/2005 Molecular Models

    Science.gov (United States)

    Vinš, Václav; Celný, David; Planková, Barbora; Němec, Tomáš; Duška, Michal; Hrubý, Jan

    2016-03-01

    In our previous study [Planková et al., EPJWeb. Conf. 92, 02071 (2015)], several molecular simulations of vapor-liquid phase interfaces for pure water were performed using the DL_POLY Classic software. The TIP4P/2005 molecular model was successfully used for the modeling of the density profile and the thickness of phase interfaces together with the temperature dependence of the surface tension. In the current study, the extended simple point charge (SPC/E) model for water was employed for the investigation of vapor-liquid phase interfaces over a wide temperature range from 250 K to 600 K. The TIP4P/2005 model was also used with the temperature step of 25 K to obtain more consistent data compared to our previous study. Results of the new simulations are in a good agreement with most of the literature data. TIP4P/2005 provides better results for the saturated liquid density with its maximum close to 275 K, while SPC/E predicts slightly better saturated vapor density. Both models give qualitatively correct representation for the surface tension of water. The maximum absolute deviation from the IAPWS standard for the surface tension of ordinary water is 10.4 mN · m-1 and 4.1 mN · m-1 over the temperature range from 275 K to 600 K in case of SPC/E and TIP4P/2005, respectively.

  18. Gelation on heating of supercooled gelatin solutions.

    Science.gov (United States)

    Guigo, Nathanaël; Sbirrazzuoli, Nicolas; Vyazovkin, Sergey

    2012-04-23

    Diluted (1.0-1.5 wt%) aqueous gelatin solutions have been cooled to -10 °C at a cooling rate 20 °C min(-1) without freezing and detectable gelation. When heated at a constant heating rate (0.5 -2 °C min(-1)), the obtained supercooled solutions demonstrate an atypical process of gelation that has been characterized by regular and stochastically modulated differential scanning calorimetry (DSC) as well as by isoconversional kinetic analysis. The process is detectable as an exothermic peak in the total heat flow of regular DSC and in the nonreversing heat flow of stochastically modulated DSC. Isoconversional kinetic analysis applied to DSC data reveals that the effective activation energy of the process increases from approximately 75 to 200 kJ mol(-1) as a supercooled solution transforms to gel on continuous heating.

  19. Dead-Ended Passive Electrolyzer with Elimination of Vapor/Liquid Separation for Life Support Oxygen Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Giner Electrochemical Systems, GES, has developed an advanced static vapor feed electrolyzer that has greatly simplified operation compared to traditional...

  20. Vapor-Liquid Equilibrium in the Mixture 1,1,1-Trichloroethane C2H3Cl3 + C6H10O Cyclohexanone (EVLM1111, LB5638_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,1,1-Trichloroethane C2H3Cl3 + C6H10O Cyclohexanone (EVLM1111, LB5638_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  1. Free energy of formation of small ice nuclei near the Widom line in simulations of supercooled water.

    Science.gov (United States)

    Buhariwalla, Connor R C; Bowles, Richard K; Saika-Voivod, Ivan; Sciortino, Francesco; Poole, Peter H

    2015-05-01

    The ST2 interaction potential has been used in a large number of simulation studies to explore the possibility of a liquid-liquid phase transition (LLPT) in supercooled water. Using umbrella sampling Monte Carlo simulations of ST2 water, we evaluate the free energy of formation of small ice nuclei in the supercooled liquid in the vicinity of the Widom line, the region above the critical temperature of the LLPT where a number of thermodynamic anomalies occur. Our results show that in this region there is a substantial free-energy cost for the formation of small ice nuclei, demonstrating that the thermodynamic anomalies associated with the Widom line in ST2 water occur in a well-defined metastable liquid phase. On passing through the Widom line, we identify changes in the free energy to form small ice nuclei that illustrate how the thermodynamic anomalies associated with the LLPT may influence the ice nucleation process.

  2. Predicting the vapor-liquid equilibrium of hydrocarbon binary mixtures and polymer solutions using predetermined pure component parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Sang Kyu [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: ycbae@hanyang.ac.kr [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer We have developed a close-packed lattice model for chain-like molecules. Black-Right-Pointing-Pointer The chain length dependence determined from Monte-Carlo simulation results were used. Black-Right-Pointing-Pointer To consider the volume effect, hole theory and two mixing steps were used. Black-Right-Pointing-Pointer A lattice fluid equation of state (LF-EoS) is presented for VLE of hydrocarbon mixtures. Black-Right-Pointing-Pointer Correlation of pure polymer solutions data with use of the LF-EoS. - Abstract: In our previous work, a new close-packed lattice model was developed for multi-component system of chain fluids with taking the chain length dependence from Monte-Carlo (MC) simulation results into account. In this work, we further extend this model to describe pressure, volume and temperature (PVT) properties, such as vapor-liquid equilibrium (VLE). To consider the effect of pressure on the phase behavior, the volume change effect is taken into account by introducing holes into the incompressible lattice model with two mixing steps. The corresponding new lattice fluid equation of state (LF-EoS) is applied to predict the thermodynamic properties of pure and binary mixtures of hydrocarbons as well as pure polymer solutions. The results of the proposed model are compared to other predictive approaches based on VLE calculations using predetermined pure model parameters without further adjustment. Thermodynamic properties predicted using the method developed in this work are consistent with the experimental data.

  3. Production of a long-term global water vapor and liquid water data set using ultra-fast methods to assimilate multi-satellite and radiosonde observations

    Science.gov (United States)

    Vonderhaar, Thomas H.; Randel, David L.; Reinke, Donald L.; Stephens, Graeme L.; Ringerud, Mark A.; Combs, Cynthia L.; Greenwald, Thomas J.; Wittmeyer, Ian L.

    1995-01-01

    There is a well-documented requirement for a comprehensive and accurate global moisture data set to assist many important studies in atmospheric science. Currently, atmospheric water vapor measurements are made from a variety of sources including radiosondes, aircraft and surface observations, and in recent years, by various satellite instruments. Creating a global data set from a single measuring system produces results that are useful and accurate only in specific situations and/or areas. Therefore, an accurate global moisture data set has been derived from a combination of these measurement systems. Under a NASA peer-reviewed contract, STC-METSAT produced two 5-yr (1988-1992) global data sets. One is the total column (integrated) water vapor data set and the other, a global layered water vapor data set using a combination of radiosonde observations, Television and Infrared Observation Satellite (TIROS) Operational Satellite (TOVS), and Special Sensor Microwave/Imager (SSM/I) data sets. STC-METSAT also produced a companion, global, integrated liquid water data set. The complete data set (all three products) has been named NVAP, an anachronym for NASA Water Vapor Project. STC-METSAT developed methods to process the data at a daily time scale and 1 x 1 deg spatial resolution.

  4. Single liquid-source plasma enhanced metalorganic chemical vapor deposition of YBa sub 2 Cu sub 3 O sub 7-x thin films. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.; Gardiner, R.; Kirlin, P.S.; Boerstler, R.W.; Steinbeck, J.

    1992-07-29

    High quality YBa2Cu3O7-x films were grown in-situ on LaAlO3 (100) by a novel single liquid source plasma-enhanced metalorganic chemical vapor deposition process. The metalorganic complexes M(thd)n, (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; M = Y, Ba, Cu) were dissolved in an organic solution and injected into a vaporizer immediately upstream of the reactor inlet The single liquid source technique dramatically simplifies current CVD processing and can significantly improve the process reproducibility. X-ray diffraction. measurements indicated that single phase, highly c-axis oriented YBa2Cu3O7-x was formed in-situ at a substrate temperature 680 degC. The as-deposited films exhibited a mirror-like surface, had transition temperature Tc = 89 K, Delta Tc < 1K, and Jc(77K) = 106 A/cm2. Plasma enhanced metalorganic chemical vapor deposition, YBCO, superconductors.

  5. The partitioning of Cu, Au and Mo between liquid and vapor at magmatic temperatures and its implications for the genesis of magmatic-hydrothermal ore deposits

    Science.gov (United States)

    Zajacz, Zoltán; Candela, Philip A.; Piccoli, Philip M.

    2017-06-01

    The partition coefficients of Cu, Au and Mo between liquid and vapor were determined at P = 130 MPa and T = 900 °C, and P = 90 MPa and T = 650 °C and redox conditions favoring the dominance of reduced S species in the fluid. The experiments at 900 °C were conducted in rapid-quench Molybdenum-Hafnium Carbide externally-heated pressure vessel assemblies, whereas those at 650 °C were run in René41 pressure vessels. The fluids were sampled at run conditions using the synthetic fluid inclusion technique. The host quartz was fractured in situ during the experiments ensuring the entrapment of equilibrium fluids. A new method was developed to quantify the composition of the vapor inclusions from LA-ICPMS analyses relying on the use of boron as an internal standard, an element that fractionates between vapor and liquid to a very small degree. The bulk starting fluid compositions closely represented those expected to exsolve from felsic silicate melts in upper crustal magma reservoirs (0.64 m NaCl, 0.32 m KCl, ±0.2 m HCl and/or 4 wt% S). The experiments were conducted in Au97Cu3 alloy capsules allowing the simultaneous determination of apparent Au and Cu solubilities in the liquid and the vapor phase. Though the apparent metal solubilities were strongly affected by the addition of HCl and S in both phases, all three elements were found to preferentially partition to a liquid phase at all studied conditions with an increasing degree of preference for the liquid in the following order Au < Cu < Mo. The presence of HCl and S did not have a significant effect on the liquid/vapor partition coefficients of either Au or Cu, whereas the presence of HCl slightly shifted the partitioning of Mo in favor of the vapor. Ore metal partition coefficients normalized to that of Na (Ki-Naliq/vap =Diliq/vap /DNaliq/vap) fall in the following ranges respectively for each studied metal: KAu-Naliq/vap = 0.20 ± 0.07-0.50 ± 0.19 (1σ); KCu-Naliq/vap = 0.36 ± 0.12-0.76 ± 0.22; KMo

  6. Simulation of two-phase liquid-vapor flows using a high-order compact finite-difference lattice Boltzmann method.

    Science.gov (United States)

    Hejranfar, Kazem; Ezzatneshan, Eslam

    2015-11-01

    A high-order compact finite-difference lattice Boltzmann method (CFDLBM) is extended and applied to accurately simulate two-phase liquid-vapor flows with high density ratios. Herein, the He-Shan-Doolen-type lattice Boltzmann multiphase model is used and the spatial derivatives in the resulting equations are discretized by using the fourth-order compact finite-difference scheme and the temporal term is discretized with the fourth-order Runge-Kutta scheme to provide an accurate and efficient two-phase flow solver. A high-order spectral-type low-pass compact nonlinear filter is used to regularize the numerical solution and remove spurious waves generated by flow nonlinearities in smooth regions and at the same time to remove the numerical oscillations in the interfacial region between the two phases. Three discontinuity-detecting sensors for properly switching between a second-order and a higher-order filter are applied and assessed. It is shown that the filtering technique used can be conveniently adopted to reduce the spurious numerical effects and improve the numerical stability of the CFDLBM implemented. A sensitivity study is also conducted to evaluate the effects of grid size and the filtering procedure implemented on the accuracy and performance of the solution. The accuracy and efficiency of the proposed solution procedure based on the compact finite-difference LBM are examined by solving different two-phase systems. Five test cases considered herein for validating the results of the two-phase flows are an equilibrium state of a planar interface in a liquid-vapor system, a droplet suspended in the gaseous phase, a liquid droplet located between two parallel wettable surfaces, the coalescence of two droplets, and a phase separation in a liquid-vapor system at different conditions. Numerical results are also presented for the coexistence curve and the verification of the Laplace law. Results obtained are in good agreement with the analytical solutions and also

  7. A novel method for controlled synthesis of nanosized hematite ({alpha}-Fe{sub 2}O{sub 3}) thin film on liquid-vapor interface

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pawan [Jaypee University of Information Technology (India); Singh, Raj Kumar [CSIR-Indian Institute of Petroleum (India); Rawat, Nitin [Gwangju Institute of Science and Technology (Korea, Republic of); Barman, Partha Bir [Jaypee University of Information Technology (India); Katyal, Subhash Chander [Jaypee Institute of Information Technology (India); Jang, Hwanchol; Lee, Heung-No, E-mail: heungno@gist.ac.kr [Gwangju Institute of Science and Technology (Korea, Republic of); Kumar, Rajesh, E-mail: rajesh.kumar@juit.ac.in [Jaypee University of Information Technology (India)

    2013-04-15

    Hematite ({alpha}-Fe{sub 2}O{sub 3}) films with a high quality surface morphology have been formed at the liquid-vapor interface using a novel approach. The surface morphology/size of the nanoparticles constituting the film is tuned in a controlled manner. It is observed that the concentration of polyvinyl alcohol in the precursor Fe{sup 3+}/Fe{sup 2+} solution, the concentration of ammonia (NH{sub 3}) vapor, and the annealing temperature are factors influencing the surface morphology/size of nanoparticles. The diameter of the {alpha}-Fe{sub 2}O{sub 3} nanoparticles inside the film is controlled to be 2-15 nm by varying the synthesis conditions, and accordingly the films have roughness in the 1.34-6.8 nm range. The prepared {alpha}-Fe{sub 2}O{sub 3} films are crystalline in nature and exhibit superparamagnetic behavior at room temperature.

  8. Emission characteristics of pulse-periodic barrier-discharge plasma in a mixture of krypton with argon and liquid freon vapor

    Science.gov (United States)

    Shuaibov, A. K.; Minya, A. I.; Gritsak, R. V.; Gomoki, Z. T.

    2014-02-01

    Radiation of a nanosecond barrier discharge in a mixture of krypton, argon, and carbon-tetrachloride vapor is studied in the spectral range of 150-300 nm. The plasma radiation spectra and the dependences of the intensities of the 258 nm Cl2( D' → A'), 222 nm KrCl( B → X), and 175 nm ArCl( B → X) bands on the partial pressure of liquid freon vapor, argon, and krypton, as well as on the discharge excitation conditions, are studied. The optimal compositions of gas mixtures for creating a broadband UV-VUV emitter based on the band system of argon chloride, krypton chloride, and chlorine molecule are determined.

  9. Dead-Ended Passive Electrolyzer with Elimination of Vapor/Liquid Separation for Life Support Oxygen Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall technical objective of the proposed Phase II NASA program is to demonstrate the ability of the WaMM™-based static vapor feed electrolyzer to...

  10. An assessment of the liquid-gas partitioning behavior of major wastewater odorants using two comparative experimental approaches: liquid sample-based vaporization vs. impinger-based dynamic headspace extraction into sorbent tubes.

    Science.gov (United States)

    Iqbal, Mohammad Asif; Kim, Ki-Hyun; Szulejko, Jan E; Cho, Jinwoo

    2014-01-01

    The gas-liquid partitioning behavior of major odorants (acetic acid, propionic acid, isobutyric acid, n-butyric acid, i-valeric acid, n-valeric acid, hexanoic acid, phenol, p-cresol, indole, skatole, and toluene (as a reference)) commonly found in microbially digested wastewaters was investigated by two experimental approaches. Firstly, a simple vaporization method was applied to measure the target odorants dissolved in liquid samples with the aid of sorbent tube/thermal desorption/gas chromatography/mass spectrometry. As an alternative method, an impinger-based dynamic headspace sampling method was also explored to measure the partitioning of target odorants between the gas and liquid phases with the same detection system. The relative extraction efficiency (in percent) of the odorants by dynamic headspace sampling was estimated against the calibration results derived by the vaporization method. Finally, the concentrations of the major odorants in real digested wastewater samples were also analyzed using both analytical approaches. Through a parallel application of the two experimental methods, we intended to develop an experimental approach to be able to assess the liquid-to-gas phase partitioning behavior of major odorants in a complex wastewater system. The relative sensitivity of the two methods expressed in terms of response factor ratios (RFvap/RFimp) of liquid standard calibration between vaporization and impinger-based calibrations varied widely from 981 (skatole) to 6,022 (acetic acid). Comparison of this relative sensitivity thus highlights the rather low extraction efficiency of the highly soluble and more acidic odorants from wastewater samples in dynamic headspace sampling.

  11. Thermodynamic scaling of molecular dynamics in supercooled ibuprofen.

    Science.gov (United States)

    Adrjanowicz, K; Wojnarowska, Z; Paluch, M; Pionteck, J

    2011-04-28

    It was shown recently that ibuprofen revealed a strong tendency to form hydrogen bonded aggregates such as dimers and trimers of either cyclic or linear geometry, which somehow seems to control molecular mobility of that drug [Brás et al. J. Phys. Chem. B2008, 112 (35), 11 087-11 099]. For such hydrogen-bonded liquids, superpositioning of dynamics under various temperature T, pressure P, and volume V conditions, when plotted versus the scaling function of T(-1)V(-γ) (where γ is a material constant), may not always be satisfying. In the present work, we have tested the validity of this scaling for supercooled ibuprofen. In order to do that, pressure-volume-temperature (PVT) measurements combined with isobaric and isothermal dielectric relaxation studies (pressure up to 310 MPa) were carried out. The scaling properties of the examined drug were derived from the fitting of the τ(α)(T,V) dependences to the modified Avramov equation and by analyzing in double logarithmic scale the T(g)(V(g)) dependences, where the glass transition temperature T(g) and volume V(g) were defined for various relaxation times. In view of the obtained results, we conjecture that for ibuprofen the thermodynamic scaling idea works but not perfectly. The slight departure from the scaling behavior is discussed in the context of the hydrogen bonding abilities of the examined system and compared with the results reported for other strongly associated liquids.

  12. Surface charge dynamics and OH and H number density distributions in near-surface nanosecond pulse discharges at a liquid / vapor interface

    Science.gov (United States)

    Winters, Caroline; Petrishchev, Vitaly; Yin, Zhiyao; Lempert, Walter R.; Adamovich, Igor V.

    2015-10-01

    The present work provides insight into surface charge dynamics and kinetics of radical species reactions in nanosecond pulse discharges sustained at a liquid-vapor interface, above a distilled water surface. The near-surface plasma is sustained using two different discharge configurations, a surface ionization wave discharge between two exposed metal electrodes and a double dielectric barrier discharge. At low discharge pulse repetition rates (~100 Hz), residual surface charge deposition after the discharge pulse is a minor effect. At high pulse repetition rates (~10 kHz), significant negative surface charge accumulation over multiple discharge pulses is detected, both during alternating polarity and negative polarity pulse trains. Laser induced fluorescence (LIF) and two-photon absorption LIF (TALIF) line imaging are used for in situ measurements of spatial distributions of absolute OH and H atom number densities in near-surface, repetitive nanosecond pulse discharge plasmas. Both in a surface ionization wave discharge and in a double dielectric barrier discharge, peak measured H atom number density, [H] is much higher compared to peak OH number density, due to more rapid OH decay in the afterglow between the discharge pulses. Higher OH number density was measured near the regions with higher plasma emission intensity. Both OH and especially H atoms diffuse out of the surface ionization wave plasma volume, up to several mm from the liquid surface. Kinetic modeling calculations using a quasi-zero-dimensional H2O vapor / Ar plasma model are in qualitative agreement with the experimental data. The results demonstrate the experimental capability of in situ radical species number density distribution measurements in liquid-vapor interface plasmas, in a simple canonical geometry that lends itself to the validation of kinetic models.

  13. Densities and vapor-liquid equilibria in binary mixtures formed by propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol at 160.0 kPa

    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.

  14. Vapor-liquid equilibrium measurements for methyl propanoate-ethanol and methyl propanoate-propan-1-ol at 101. 32 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Susial, P.; Ortega, J. (Catedra de Termodinamica y Fisicoquimica, Escuela Superior de Ingenieros Industriales, Polytechnic University of Canarias, 35017 Las Palmas, Canary Islands (ES)); DeAlfonso, C.; Alonso, C. (Unidad de Tribologia e Ingenieria Quimica, Instituto Rocasolano, CSIC, Madrid (ES))

    1989-04-01

    Isobaric vapor-liquid equilibrium measurements on binary systems of methyl propanoate with ethanol and propan-1-ol are taken at a constant pressure of 101.32 +- 0.02 kPa. These systems exhibit significant deviations from ideality and are shown to be thermodynamically consistent. The methyl propanoate-ethanol system forms an azeotrope at x = y = 0.483 and T = 345.58{Kappa}. Experimental data are fitted to a suitable equation and are likewise compared with the values predicted by the UNIFAC and ASOG models.

  15. New phase equilibrium analyzer for determination of the vapor-liquid equilibrium of carbon dioxide and permanent gas mixtures for carbon capture and storage.

    Science.gov (United States)

    Ke, Jie; Parrott, Andrew J; Sanchez-Vicente, Yolanda; Fields, Peter; Wilson, Richard; Drage, Trevor C; Poliakoff, Martyn; George, Michael W

    2014-08-01

    A high-pressure, phase equilibrium analyzer incorporating a fiber-optic reflectometer is described. The analyzer has been designed for measuring the vapor-liquid equilibrium data of multi-component mixtures of carbon dioxide and permanent gases, providing a novel tool to acquire of a large number of phase equilibrium data for the development of the new carbon capture and storage technologies. We demonstrate that the analyzer is suitable for determining both the bubble- and dew-point lines at temperature from 253 K and pressure up to 25 MPa using pure CO2 and two binary mixtures of CO2 + N2 and CO2 + H2.

  16. Ionic liquids as superior solvents for headspace gas chromatography of residual solvents with very low vapor pressure, relevant for pharmaceutical final dosage forms.

    Science.gov (United States)

    Laus, Gerhard; Andre, Max; Bentivoglio, Gino; Schottenberger, Herwig

    2009-08-07

    1-n-Butyl-3-methylimidazolium dimethyl phosphate (BMIM DMP) was identified as the most suitable ionic liquid as solvent for the headspace gas chromatographic analysis of solvents with very low vapor pressure such as dimethylsulfoxide, N-methylpyrrolidone, sulfolane, tetralin, and ethylene glycol in a realistic matrix of commonly used excipients (carboxymethylcellulose, magnesium stearate, guar flour, and corn starch) in pharmaceutical products. Limits of quantification and limits of detection were in the low microgram per gram range. The detection of traces of sulfolane in a real sample of tablets containing the drug cefpodoxim proxetil demonstrated the applicability of the method.

  17. Single liquid source plasma-enhanced metalorganic chemical vapor deposition of high-quality YBa2Cu3O(7-x) thin films

    Science.gov (United States)

    Zhang, Jiming; Gardiner, Robin A.; Kirlin, Peter S.; Boerstler, Robert W.; Steinbeck, John

    1992-01-01

    High quality YBa2Cu3O(7-x) films were grown in-situ on LaAlO3 (100) by a novel single liquid source plasma-enhanced metalorganic chemical vapor deposition process. The metalorganic complexes M(thd) (sub n), (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; M = Y, Ba, Cu) were dissolved in an organic solution and injected into a vaporizer immediately upstream of the reactor inlet. The single liquid source technique dramatically simplifies current CVD processing and can significantly improve the process reproducibility. X-ray diffraction measurements indicated that single phase, highly c-axis oriented YBa2Cu3O(7-x) was formed in-situ at substrate temperature 680 C. The as-deposited films exhibited a mirror-like surface, had transition temperature T(sub cO) approximately equal to 89 K, Delta T(sub c) less than 1 K, and Jc (77 K) = 10(exp 6) A/sq cm.

  18. Molecular dynamics study of the effect of calcium ions on the monolayer of SDC and SDSn surfactants at the vapor/liquid interface.

    Science.gov (United States)

    Yan, Hui; Guo, Xin-Li; Yuan, Shi-Ling; Liu, Cheng-Bu

    2011-05-17

    The effect of Ca(2+) ions on the hydration shell of sodium dodecyl carboxylate (SDC) and sodium dodecyl sulfonate (SDSn) monolayer at vapor/liquid interfaces was studied using molecular dynamics simulations. For each surfactant, two different surface concentrations were used to perform the simulations, and the aggregation morphologies and structural details have been reported. The results showed that the aggregation structures relate to both the surface coverage and the calcium ions. The divalent ions can screen the interaction between the polar head and Na(+) ions. Thus, Ca(2+) ions locate near the vapor/liquid interface to bind to the headgroup, making the aggregations much more compact via the salt bridge. The potential of mean force (PMF) between Ca(2+) and the headgroups shows that the interaction is decided by a stabilizing solvent-separated minimum in the PMF. To bind to the headgroup, Ca(2+) should overcome the energy barrier. Among contributions to the PMF, the major repulsive interaction was due to the rearrangement of the hydration shell after the calcium ions entered into the hydration shell of the headgroup. The PMFs between the headgroup and Ca(2+) in the SDSn systems showed higher energy barriers than those in the SDC systems. This result indicated that SDSn binds the divalent ions with more difficulty compared with SDC, so the ions have a strong effect on the hydration shell of SDC. That is why sulfonate surfactants have better efficiency in salt solutions with Ca(2+) ions for enhanced oil recovery.

  19. Quantification of VX vapor in ambient air by liquid chromatography isotope dilution tandem mass spectrometric analysis of glass bead filled sampling tubes.

    Science.gov (United States)

    Evans, Ronald A; Smith, Wendy L; Nguyen, Nam-Phuong; Crouse, Kathy L; Crouse, Charles L; Norman, Steven D; Jakubowski, E Michael

    2011-02-15

    An analysis method has been developed for determining low parts-per-quadrillion by volume (ppqv) concentrations of nerve agent VX vapor actively sampled from ambient air. The method utilizes glass bead filled depot area air monitoring system (DAAMS) sampling tubes with isopropyl alcohol extraction and isotope dilution using liquid chromatography coupled with a triple-quadrupole mass spectrometer (LC/MS/MS) with positive ion electrospray ionization for quantitation. The dynamic range was from one-tenth of the worker population limit (WPL) to the short-term exposure limit (STEL) for a 24 L air sample taken over a 1 h period. The precision and accuracy of the method were evaluated using liquid-spiked tubes, and the collection characteristics of the DAAMS tubes were assessed by collecting trace level vapor generated in a 1000 L continuous flow chamber. The method described here has significant improvements over currently employed thermal desorption techniques that utilize a silver fluoride pad during sampling to convert VX to a higher volatility G-analogue for gas chromatographic analysis. The benefits of this method are the ability to directly analyze VX with improved selectivity and sensitivity, the injection of a fraction of the extract, quantitation using an isotopically labeled internal standard, and a short instrument cycle time.

  20. Single liquid source plasma-enhanced metalorganic chemical vapor deposition of high-quality YBa2Cu3O(7-x) thin films

    Science.gov (United States)

    Zhang, Jiming; Gardiner, Robin A.; Kirlin, Peter S.; Boerstler, Robert W.; Steinbeck, John

    1992-01-01

    High quality YBa2Cu3O(7-x) films were grown in-situ on LaAlO3 (100) by a novel single liquid source plasma-enhanced metalorganic chemical vapor deposition process. The metalorganic complexes M(thd) (sub n), (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; M = Y, Ba, Cu) were dissolved in an organic solution and injected into a vaporizer immediately upstream of the reactor inlet. The single liquid source technique dramatically simplifies current CVD processing and can significantly improve the process reproducibility. X-ray diffraction measurements indicated that single phase, highly c-axis oriented YBa2Cu3O(7-x) was formed in-situ at substrate temperature 680 C. The as-deposited films exhibited a mirror-like surface, had transition temperature T(sub cO) approximately equal to 89 K, Delta T(sub c) less than 1 K, and Jc (77 K) = 10(exp 6) A/sq cm.