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Sample records for air-water countercurrent flow

  1. A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)] [and others

    1995-09-01

    This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.

  2. Experimental investigation of droplet separation in a horizontal counter-current air/water stratified flow; Experimentelle Untersuchung der Tropfenabscheidung einer horizontalen, entgegengerichteten Wasser/Luft-Schichtenstroemung

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Stephan Gerhard

    2015-07-01

    A stratified counter-current two-phase gas/liquid flow can occur in various technical systems. In the past investigations have mainly been motivated by the possible occurrence of these flows in accident scenarios of nuclear light water-reactors and in numerous applications in process engineering. However, the precise forecast of flow parameters, is still challenging, for instance due to their strong dependency on the geometric boundary conditions. A new approach which uses CFD methods (Computational Fluid Dynamics) promises a better understanding of the flow phenomena and simultaneously a higher scalability of the findings. RANS methods (Reynolds Averaged Navier Stokes) are preferred in order to compute industrial processes and geometries. A very deep understanding of the flow behavior and equation systems based on real physics are necessary preconditions to develop the equation system for a reliable RANS approach with predictive power. Therefore, local highly resolved, experimental data is needed in order to provide and validate the required turbulence and phase interaction models. The central objective of this work is to provide the data needed for the code development for these unsteady, turbulent and three-dimensional flows. Experiments were carried out at the WENKA facility (Water Entrainment Channel Karlsruhe) at the Karlsruhe Institute of Technology (KIT). The work consists of a detailed description of the test-facility including a new bended channel, the measurement techniques and the experimental results. The characterization of the new channel was done by flow maps. A high-speed imaging study gives an impression of the occurring flow regimes, and different flow phenomena like droplet separation. The velocity distributions as well as various turbulence values were investigated by particle image velocimetry (PIV). In the liquid phase fluorescent tracer-particles were used to suppress optical reflections from the phase surface (fluorescent PIV, FPIV

  3. COUNTERCURRENT FLOW LIMITATION EXPERIMENTS AND MODELING FOR IMPROVED REACTOR SAFETY

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, Karen

    2008-09-26

    This project is investigating countercurrent flow and “flooding” phenomena in light water reactor systems to improve reactor safety of current and future reactors. To better understand the occurrence of flooding in the surge line geometry of a PWR, two experimental programs were performed. In the first, a test facility with an acrylic test section provided visual data on flooding for air-water systems in large diameter tubes. This test section also allowed for development of techniques to form an annular liquid film along the inner surface of the “surge line” and other techniques which would be difficult to verify in an opaque test section. Based on experiences in the air-water testing and the improved understanding of flooding phenomena, two series of tests were conducted in a large-diameter, stainless steel test section. Air-water test results and steam-water test results were directly compared to note the effect of condensation. Results indicate that, as for smaller diameter tubes, the flooding phenomena is predominantly driven by the hydrodynamics. Tests with the test sections inclined were attempted but the annular film was easily disrupted. A theoretical model for steam venting from inclined tubes is proposed herein and validated against air-water data. Empirical correlations were proposed for air-water and steam-water data. Methods for developing analytical models of the air-water and steam-water systems are discussed, as is the applicability of the current data to the surge line conditions. This report documents the project results from July 1, 2005 through June 30, 2008.

  4. Air-water flow in subsurface systems

    Science.gov (United States)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  5. VOF Calculations of Countercurrent Gas-Liquid Flow in a PWR Hot Leg

    Directory of Open Access Journals (Sweden)

    M. Murase

    2012-01-01

    Full Text Available We improved the computational grid and schemes in the VOF (volume of fluid method with the standard − turbulent model in our previous study to evaluate CCFL (countercurrent flow limitation characteristics in a full-scale PWR hot leg (750 mm diameter, and the calculated CCFL characteristics agreed well with the UPTF data at 1.5 MPa. In this paper, therefore, to evaluate applicability of the VOF method to different fluid properties and a different scale, we did numerical simulations for full-scale air-water conditions and the 1/15-scale air-water tests (50 mm diameter, respectively. The results calculated for full-scale conditions agreed well with CCFL data and showed that CCFL characteristics in the Wallis diagram were mitigated under 1.5 MPa steam-water conditions comparing with air-water flows. However, the results calculated for the 1/15-scale air-water tests greatly underestimated the falling water flow rates in calculations with the standard − turbulent model, but agreed well with the CCFL data in calculations with a laminar flow model. This indicated that suitable calculation models and conditions should be selected to get good agreement with data for each scale.

  6. COHERENT STRUCTURES IN COUNTERCURRENT AXISYMMETRIC SHEAR FLOWS

    Institute of Scientific and Technical Information of China (English)

    谢锡麟; 麻伟巍; 周慧良

    2003-01-01

    The dynamical behaviors of coherent structures in countercurrent axisymmetric shear flows are experimentally studied. The forward velocity U1 and the velocity ratio R = (U1 - U2)/(U1 +U2), where U2 denotes the suction velocity, are considered as the control parameters. Two kinds of vortex structures, i.e., axisymmetric and helical structures, were discovered with respect to different regimes in the R versus U1 diagram. In the case of U1 ranging from 3 to 20 m/s and R from 1 to 3, the axisymmetric structures play an important role. Based on the dynamical behaviors of axisymmetric structures, a critical forward velocity Ucr1 = 6.8 m/s was defined, subsequently, the subcritical velocity regime: U1 > Ucr1 and the supercritical velocity regime: U1 < Ucr1. In the subcritical velocity regime,the flow system contains shear layer self-excited oscillations in a certain range of the velocity ratio with respect to any forward velocity. In the supercritical velocity regime, the effect of the velocity ratio could be explained by the relative movement and the spatial evolution of the axisymmetric structure undergoes the following stages: (1) Kelvin-Helmholtz instability leading to vortex rolling up, (2) first time vortex agglomeration, (3) jet column self-excited oscillation, (4) shear layer self-excited oscillation,(5) "ordered tearing", (6) turbulence in the case of U1 < 4 m/s (the "ordered tearing" does not exist when U1 > 4m/s), correspondingly, the spatial evolution of the temporal asymptotic behavior of a dynamical system can be described as follows: (1) Hopf bifurcation, (2) subharmonic bifurcation, (3)reversed superharmonic bifurcation, (4) superharmonic bifurcation, (5) chaos ("weak turbulence") in the case of U1 < 4 m/s (superharmonic bifurcation does not exist when U1 > 4 m/s). The proposed new terms, superharmonic and reversed superharmonic bifurcations, are characterized of the frequency doubling rather than the period doubling. A kind of unfamiliar

  7. Flooding in counter-current two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Ragland, W.A.; Ganic, E.N.

    1982-01-01

    Flooding is a phenomenon which is best described as the transition from counter-current to co-current flow. Early notice was taken of this phenomenon in the chemical engineering industry. Flooding also plays an important role in the field of two-phase heat transfer since it is a limit for many systems involving counter-current flow. Practical applications of flooding limited processes include wickless thermosyphons and the emergency core cooling system (ECCS) of pressurized water nuclear reactors. The phenomenon of flooding also is involved in the behavior of nuclear reactor core materials during severe accident conditions where flooding is one of the mechanisms governing the motion of the molten fuel pin cladding.

  8. Evaluation of dual flow counter-current chromatography and intermittent counter-current extraction.

    Science.gov (United States)

    Ignatova, Svetlana; Hewitson, Peter; Mathews, Ben; Sutherland, Ian

    2011-09-09

    The aim of this research is to compare two continuous extraction technologies, intermittent counter-current extraction (ICcE) and dual flow counter-current chromatography (DFCCC), in terms of loading and throughput using the GUESSmix, and show the advantages and disadvantages of the two methods. A model sample containing caffeine, vanillin, naringenin and carvone, with a total load of 11.2 g, was employed with a hexane-ethyl acetate-methanol-water (2:3:2:3) phase system to evaluate an ICcE method on a preparative (912 ml coil volume) DE-Midi instrument. While DFCCC was carried out on a specially designed preparative (561 ml coil volume) bobbin installed in a similar Midi instrument case. While similar throughputs of 7.8 g/h and 6.9 g/h were achieved for the ICcE and DFCCC methods respectively, ICcE was demonstrated to have a number of advantages over DFCCC.

  9. Countercurrent flow limited (CCFL) heat flux in the high flux isotope reactor (HFIR) fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Ruggles, A.E.

    1990-10-12

    The countercurrent flow (CCF) performance in the fuel element region of the HFIR is examined experimentally and theoretically. The fuel element consists of two concentric annuli filled with aluminum clad fuel plates of 1.27 mm thickness separated by 1.27 mm flow channels. The plates are curved as they go radially outward to accomplish constant flow channel width and constant metal-to-coolant ratio. A full-scale HFIR fuel element mock-up is studied in an adiabatic air-water CCF experiment. A review of CCF models for narrow channels is presented along with the treatment of CCFs in system of parallel channels. The experimental results are related to the existing models and a mechanistic model for the annular'' CCF in a narrow channel is developed that captures the data trends well. The results of the experiment are used to calculate the CCFL heat flux of the HFIR fuel assembly. It was determined that the HFIR fuel assembly can reject 0.62 Mw of thermal power in the CCFL situation. 31 refs., 17 figs.

  10. Wall pressure measurements of flooding in vertical countercurrent annular air–water flow

    Energy Technology Data Exchange (ETDEWEB)

    Choutapalli, I., Vierow, K.

    2010-01-01

    An experimental study of flooding in countercurrent air-water annular flow in a large diameter vertical tube using wall pressure measurements is described in this paper. Axial pressure profiles along the length of the test section were measured up to and after flooding using fast response pressure transducers for three representative liquid flow rates representing a wide range of liquid Reynolds numbers (ReL = 4Γ/μ; Γ is the liquid mass flow rate per unit perimeter; μ is the dynamic viscosity) from 3341 to 19,048. The results show that flooding in large diameter tubes cannot be initiated near the air outlet and is only initiated near the air inlet. Fourier analysis of the wall pressure measurements shows that up to the point of flooding, there is no dominant wave frequency but rather a band of frequencies encompassing both the low frequency and the broad band that are responsible for flooding. The data indicates that flooding in large diameter vertical tubes may be caused by the constructive superposition of a plurality of waves rather than the action of a single large-amplitude wave.

  11. Stability of steam-water countercurrent stratified flow

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S C

    1985-10-01

    Two flow instabilities which limit the normal condensation processes in countercurrent stratified steam-water flow have been identified experimentally: flooding and condensation-induced waterhammer. In order to initiate condensation-induced waterhammer in nearly horizontal or moderately-inclined steam/subcooled-water flow, two conditions, the appearance of a wavy interface and complete condensation of the incoming steam, are necessary. Analyses of these conditions are performed on a basis of flow stability and heat transfer considerations. Flooding data for several inclinations and channel heights are collected. Effects of condensation, inclination angle and channel height on the flooding characteristics are discussed. An envelope theory for the onset of flooding in inclined stratified flow is developed, which agrees well with the experimental data. Some empirical information on basic flow parameters, such as mean film thickness and interfacial friction factor required for this theory are measured. The previous viewpoints on flooding appear not to conflict with the present experimental data in nearly horizontal flow but the flooding phenomena in nearly vertical flow appear to be more complicated than those described by these viewpoints because of liquid droplet entrainment.

  12. Ultraefficient reduced model for countercurrent two-layer flows

    Science.gov (United States)

    Lavalle, Gianluca; Vila, Jean-Paul; Lucquiaud, Mathieu; Valluri, Prashant

    2017-01-01

    We investigate the dynamics of two superposed layers with density contrast flowing countercurrent inside a channel, when the lower layer is much thinner than the wavelength of interfacial waves. We apply a low-dimensional film model to the bottom (heavier) layer and introduce a fast and efficient method to predict the onset of flow reversal in this phase. We study three vertical scenarios with different applied pressure gradients and compare the temporal growth rates of linear and weakly nonlinear waves to the Orr-Sommerfeld problem and to the weakly nonlinear theory, respectively. At the loading point, i.e., when a large wave hump stands at the interface, our spatiotemporal analysis shows that the system is absolutely unstable. We then present profiles of nonlinear saturated waves, pressure field, and streamline distribution in agreement with direct numerical simulation. The reduced model presented here allows us to explore the effect of the upper-layer speed on the wave pattern, showing that the wave profile is very sensitive when the mean film thickness, rather than the liquid flow rate, is maintained constant in the simulation. In addition, we show the strong effect of surface tension on both the maximum wave hump and the crest steepness before the loading point. Finally, we reveal how the nonlinear wave speed affects the vortex distribution within the lower layer by analyzing the stream function under different scenarios.

  13. Local properties of countercurrent stratified steam-water flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H J

    1985-10-01

    A study of steam condensation in countercurrent stratified flow of steam and subcooled water has been carried out in a rectangular channel/flat plate geometry over a wide range of inclination angles (4/sup 0/-87/sup 0/) at several aspect ratios. Variables were inlet water and steam flow rates, and inlet water temperature. Local condensation rates and pressure gradients were measured, and local condensation heat transfer coefficients and interfacial shear stress were calculated. Contact probe traverses of the surface waves were made, which allowed a statistical analysis of the wave properties. The local condensation Nusselt number was correlated in terms of local water and steam Reynolds or Froude numbers, as well as the liquid Prandtl number. A turbulence-centered model developed by Theofanous, et al. principally for gas absorption in several geometries, was modified. A correlation for the interfacial shear stress and the pressure gradient agreed with measured values. Mean water layer thicknesses were calculated. Interfacial wave parameters, such as the mean water layer thickness, liquid fraction probability distribution, wave amplitude and wave frequency, are analyzed.

  14. CFD studies on the phenomena around counter-current flow limitations of gas/liquid two-phase flow in a model of a PWR hot leg

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto, E-mail: deendarlianto@ugm.ac.id [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2, Yogyakarta 55281 (Indonesia); Hoehne, Thomas; Lucas, Dirk; Vallee, Christophe [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Zabala, Gustavo Adolfo Montoya [Department of Chemical Engineering, Simon Bolivar University, Valle of Sartenejas, Caracas 1080 (Venezuela, Bolivarian Republic of)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer We modelled CCFL in a PWR hot leg using Algebraic Interfacial Area Density model. Black-Right-Pointing-Pointer The model is able to distinguish the local flow morphologies. Black-Right-Pointing-Pointer Test fluids are air-water and steam-water. Black-Right-Pointing-Pointer Calculated CCFL and water level are in good agreement with experimental data. - Abstract: In order to improve the understanding of counter-current two-phase flow and to validate new physical models, CFD simulations of a 1/3rd scale model of the hot leg of a German Konvoi pressurized water reactor (PWR) with rectangular cross section were performed. Selected counter-current flow limitation (CCFL) experiments conducted at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) were calculated with ANSYS CFX using the multi-fluid Euler-Euler modelling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a shear stress transport (SST) turbulence model. In the simulation, the drag law was approached by a newly developed correlation of the drag coefficient in the Algebraic Interfacial Area Density (AIAD) model. The model can distinguish the bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicate also a quantitative agreement between calculations and experimental data for the CCFL characteristics and the water level inside the hot leg channel.

  15. The effects of surface tension on flooding in counter-current two-phase flow in an inclined tube

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto [Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No.2 Yogyakarta 55281 (Indonesia); Forschungszentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Ousaka, Akiharu [Department of Mechanical Engineering, The University of Tokushima, 2-1 Minami Josanjima, Tokushima 770-8506 (Japan); Indarto [Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No.2 Yogyakarta 55281 (Indonesia); Kariyasaki, Akira [Department of Chemical Engineering, Fukuoka University, 8-19-1, Jyonan-ku, Fukuoka 814-0180 (Japan); Lucas, Dirk; Vallee, Christophe [Forschungszentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Vierow, Karen; Hogan, Kevin [Department of Nuclear Engineering Texas A and M University, 129 Zachry Engineering Center, 3133 TAMU College Station, TX 77843-3133 (United States)

    2010-10-15

    The purpose of the present study is to investigate the effects of surface tension on flooding phenomena in counter-current two-phase flow in an inclined tube. Previous studies by other researchers have shown that surface tension has a stabilizing effect on the falling liquid film under certain conditions and a destabilizing or unclear trend under other conditions. Experimental results are reported herein for air-water systems in which a surfactant has been added to vary the liquid surface tension without altering other liquid properties. The flooding section is a tube of 16 mm in inner diameter and 1.1 m length, inclined at 30-60 from horizontal. The flooding mechanisms were observed by using two high-speed video cameras and by measuring the time variation of liquid hold-up along the test tube. The results show that effects of surface tension are significant. The gas velocity needed to induce flooding is lower for a lower surface tension. There was no upward motion of the air-water interfacial waves upon flooding occurrence, even for lower a surface tension. Observations on the liquid film behavior after flooding occurred suggest that the entrainment of liquid droplets plays an important role in the upward transport of liquid. Finally, an empirical correlation for flooding velocities is proposed that includes functional dependencies on surface tension and tube inclination. (author)

  16. Numerical simulation of air-water two-phase flow over stepped spillways

    Institute of Scientific and Technical Information of China (English)

    CHENG; Xiangju; CHEN; Yongcan

    2006-01-01

    Stepped spillways for significant energy dissipation along the chute have gained interest and popularity among researchers and dam engineers. Due to the complexity of air-water two-phase flow over stepped spillways, the finite volume computational fluid dynamics module of the FLUENT software was used to simulate the main characteristics of the flow. Adopting the RNG k-ε turbulence model, the mixture flow model for air-water two-phase flow was used to simulate the flow field over stepped spillway with the PISO arithmetic technique. The numerical result successfully reproduced the complex flow over a stepped spillway of an experiment case, including the interaction between entrained air bubbles and cavity recirculation in the skimming flow regime, velocity distribution and the pressure profiles on the step surface as well. The result is helpful for understanding the detailed information about energy dissipation over stepped spillways.

  17. AN EXPERIMENTAL STUDY ON THE COHERENT STRUCTURES AND CHAOTIC PHENOMENA IN THE AXISYMMETRIC COUNTERCURRENT SHEAR FLOW

    Institute of Scientific and Technical Information of China (English)

    麻伟巍; 谢锡麟; 周慧良

    2001-01-01

    The coherent structures and the chaotic phenomena in the transition of the axisymmetric countercurrent mixing shear flow were investigated experimentally. Two kinds of self-excited oscillation modes could exist in the axisymmetric countercurrent mixing shear flow. One is the shear layer self-excited oscillation mode corresponding to the high Reynolds number regime and the other is the jet column self-excited oscillation mode corresponding to the low Reynolds number regime in the case of the velocity ratio ranging from 1 to 1.5. Analyzing the auto-power spec trum, self-correlation-function and three dimensional reconstructed phase trajectory,the route to chaos through three Hopf bifurcations intercepted by an intermittence of the dynamical system corresponding to the axisymmetric countercurrent mixing shear flow was discovered when the velocity ratio is equal to 1.32.

  18. Patterns of a slow air-water flow in a semispherical container

    DEFF Research Database (Denmark)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.

    2016-01-01

    This numerical study analyzes the development of eddies in a slow steady axisymmetric air-water flow in a sealed semispherical container, driven by a rotating top disk. As the water height, Hw, increases, new flow cells emerge in both water and air. First, an eddy emerges near the axis-bottom int......This numerical study analyzes the development of eddies in a slow steady axisymmetric air-water flow in a sealed semispherical container, driven by a rotating top disk. As the water height, Hw, increases, new flow cells emerge in both water and air. First, an eddy emerges near the axis...... on the air flow. In contrast to flows in cylindrical and conical containers, there is no interaction with Moffatt corner vortices here....

  19. Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows

    Science.gov (United States)

    Schmidt, Patrick; Ó Náraigh, Lennon; Lucquiaud, Mathieu; Valluri, Prashant

    2016-04-01

    We consider the genesis and dynamics of interfacial instability in vertical gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of two main flow parameters on the interfacial dynamics, namely the film thickness and pressure drop applied to drive the gas stream. To make contact with existing studies in the literature, the effect of various density contrasts is also examined. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable interfacial mode for low density contrast. A study of absolute and convective instability for low density contrast shows that the system is absolutely unstable for all but two narrow regions of the investigated parameter space. Direct numerical simulations of the same system (low density contrast) show that linear theory holds up remarkably well upon the onset of large-amplitude waves as well as the existence of weakly nonlinear waves. For high density contrasts, corresponding more closely to an air-water-type system, linear stability theory is also successful at determining the most-dominant features in the interfacial wave dynamics at early-to-intermediate times. Nevertheless, the short waves selected by the linear theory undergo secondary instability and the wave train is no longer regular but rather exhibits chaotic motion. The same linear stability theory predicts when the direction of travel of the waves changes — from downwards to upwards. We outline the practical implications of this change in terms of loading and flooding. The change in direction of the

  20. An investigation of counter-current flow in porous media with history-dependent modeling

    Science.gov (United States)

    Li, G.; Grader, A. S.; Halleck, P. H.; Karpyn, Z. T.

    2003-04-01

    Counter-current fluid flow occurs in many reservoir processes. It is important to understand and model these processes in order to operate them effectively. Both drainage and imbibition processes exist simultaneously when counter-current flow occurs. It has thus proven difficult to model this type of flow, especially when fluid banks form. Previously, counter-current flow experiments have been done in glass bead packs and the spatial and temporal saturation distributions obtained with X-ray computed tomography (CT). In the current paper, a new saturation-history-dependent approach has been developed to simulate the experiments. Hysteresis in both capillary pressure and relative permeabilities is considered during the process of matching the simulation results to experimental data. Capillary pressure and relative permeabilities are extracted with the aid of a deterministic reservoir simulator. During the history matching process, a family of curves (called scanning curves) is constructed connecting the two branches of the capillary hystersis loop. Each grid block of the sample is assigned a different scanning curve according to its saturation history. Simulation of the experiments reproduced two-dimensional saturation distributions over time with good accuracy. Similar results could not be obtained with traditional simulation using only one capillary pressure curve. History-dependent modeling successfully predicted cross-diameter counter-current flow in a cylindrical geometry. The parameters used in the single capillary pressure method are the average of the parameters used in the history-dependent method. Total effective mobility controls the flow process, being smaller in counter-current flow than in co-current flow. Experiments documented in the literature that exhibited formation of fluid banks were also successfully simulated. We anticipate that application of this method will improve the prediction of full-scale fluid flow processes such as ground water

  1. Hydrodynamic behaviour of a gas—solid counter-current packed column at trickle flow

    NARCIS (Netherlands)

    Roes, A.W.M.; Swaaij, van W.P.M.

    1979-01-01

    Trickle flow of a more or less fluidized catalyst through a packed column is a promising new gas—solid counter-current operation. The hydrodynamic, behaviour of such a column, filled with dumped PALL rings, has been investigated, while some results have been obtained with RASCHIG rings and cylindric

  2. Physical modelling and scale effects of air-water flows on stepped spillways

    Institute of Scientific and Technical Information of China (English)

    CHANSON Hubert; GONZALEZ Carlos A.

    2005-01-01

    During the last three decades, the introduction of new construction materials (e.g. RCC (Roller Compacted Concrete),strengthened gabions) has increased the interest for stepped channels and spillways. However stepped chute hydraulics is not simple, because of different flow regimes and importantly because of very-strong interactions between entrained air and turbulence. In this study, new air-water flow measurements were conducted in two large-size stepped chute facilities with two step heights in each facility to study experimental distortion caused by scale effects and the soundness of result extrapolation to prototypes. Experimental data included distributions of air concentration, air-water flow velocity, bubble frequency, bubble chord length and air-water flow turbulence intensity. For a Froude similitude, the results implied that scale effects were observed in both facilities, although the geometric scaling ratio was only Lr=2 in each case. The selection of the criterion for scale effects is a critical issue. For example, major differences (i.e. scale effects) were observed in terms of bubble chord sizes and turbulence levels although little scale effects were seen in terms of void fraction and velocity distributions. Overall the findings emphasize that physical modelling of stepped chutes based upon a Froude similitude is more sensitive to scale effects than classical smooth-invert chute studies, and this is consistent with basic dimensional analysis developed herein.

  3. Liquid mean velocity and turbulence in a horizontal air-water bubbly flow

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The liquid phase turbulent structure of an air-water bubbly horizontal flow in a circular pipe has been investigated experimentally. Three-dimensional measurements were implemented with two "X" type probes oriented in different planes, and local liquid-phase velocities and turbulent stresses were simultaneously obtained. Systematic measurements were conducted covering a range of local void fraction from 0 to 11.7%. The important experiment results and parametric trends are summarized and discussed.

  4. Drag reductions and the air-water interface stability of superhydrophobic surfaces in rectangular channel flow

    Science.gov (United States)

    Zhang, Jingxian; Yao, Zhaohui; Hao, Pengfei

    2016-11-01

    Flow in a rectangular channel with superhydrophobic (SH) top and bottom walls was investigated experimentally. Different SH surfaces, including hierarchical structured surfaces and surfaces with different micropost sizes (width and spacing) but the same solid fraction, were fabricated and measured. Pressure loss and flow rate in the channel with SH top and bottom walls were measured, with Reynolds number changing from 700 to 4700, and the corresponding friction factor for the SH surface was calculated. The statuses of the air plastron on different SH surfaces were observed during the experiment. In our experiment, compared with the experiment for the smooth surface, drag reductions were observed for all SH surfaces, with the largest drag reduction of 42.2%. It was found that the hierarchy of the microstructure can increase the drag reduction by decreasing the solid fraction and enhancing the stability of the air-water interface. With a fixed solid fraction, the drag reduction decreases as the post size (width and spacing) increases, due to the increasing curvature and instability effects of the air-water interface. A correlation parameter between the contact angle hysteresis, the air-water interface stability, and the drag reduction of the SH surfaces was found.

  5. A PCM/forced convection conjugate transient analysis of energy storage systems with annular and countercurrent flows

    Science.gov (United States)

    Cao, Y.; Faghri, A.; Juhasz, A.

    1991-01-01

    Latent heat energy storage systems with both annular and countercurrent flows are modeled numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. It is found that the energy storage system with the countercurrent flow is an efficient way to absorb heat energy in a short period for pulsed power load space applications.

  6. Sensitivity study of poisson corruption in tomographic measurements for air-water flows

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, P. (Fraunhofer Institute for Nondestructive Testing, Saarbrucken (Germany)); Vaidya, M.S. (Indian Institute of Technology, Kanpur (India))

    1993-01-01

    An application of computerized tomography (CT) for measuring void fraction profiles in two-phase air-water flows was reported earlier. Those attempts involved some special radial methods for tomographic reconstruction and the popular convolution backprojection (CBP) method. The CBP method is capable of reconstructing void profiles for nonsymmetric flows also. In this paper, we investigate the effect of corrupted CT data for gamma-ray sources and aCBP algorithm. The corruption in such a case is due to the statistical (Poisson) nature of the source.

  7. Two-phase air-water flows:Scale effects in physical modeling

    Institute of Scientific and Technical Information of China (English)

    PFISTER Michael; CHANSON Hubert

    2014-01-01

    Physical modeling represents probably the oldest design tool in hydraulic engineering together with analytical approaches. In free surface flows, the similitude based upon a Froude similarity allows for a correct representation of the dominant forces, namely gravity and inertia. As a result fluid flow properties such as the capillary forces and the viscous forces might be incorrectly reproduced, affecting the air entrainment and transport capacity of a high-speed model flow. Small physical models operating under a Froude similitude systematically underestimate the air entrainment rate and air-water interfacial properties. To limit scale effects, minimal values of Reynolds or Weber number have to be respected. The present article summarizes the physical background of such limitations and their combination in terms of the Morton number. Based upon a literature review, the existing limits are presented and discussed, resulting in a series of more conservative recommendations in terms of air concentration scaling. For other air-water flow parameters, the selection of the criteria to assess scale effects is critical because some parameters (e.g., bubble sizes, turbulent scales) can be affected by scale effects, even in relatively large laboratory models.

  8. An investigation of channel flow with a smooth air-water interface

    Science.gov (United States)

    Madad, Reza; Elsnab, John; Chin, Cheng; Klewicki, Joseph; Marusic, Ivan

    2015-06-01

    Experiments and numerical simulation are used to investigate fully developed laminar and turbulent channel flow with an air-water interface as the lower boundary condition. Laser Doppler velocimetry measurements of streamwise and wall-normal velocity components are made over a range of Reynolds number based upon channel height and bulk velocity from 1100 to 4300, which encompasses the laminar, transitional and low Reynolds numbers turbulent regimes. The results show that the airflow statistics near the stationary wall are not significantly altered by the air-water moving interface and reflect those found in channel flows. The mean statistics on the water interface side largely exhibit results similar to simulated Poiseuille-Couette flow (PCF) with a solid moving wall. For second-order statistics, however, the simulation and experimental results show some discrepancies near the moving water surface, suggesting that a full two-phase simulation is required. A momentum and energy transport tubes analysis is investigated for laminar and turbulent PCFs. This analysis builds upon the classical notion of a streamtube and indicates that part of the energy from the pressure gradient is transported towards the stationary wall and is dissipated as heat inside the energy tubes, while the remainder is transmitted to the moving wall. For the experiments, the airflow energy is transmitted towards the water to overcome the drag force and drive the water forward; therefore, the amount of energy transferred to the water is higher than the energy transferred to a solid moving wall.

  9. Interfacial structures of confined air-water two-phase bubbly flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Ishii, M.; Wu, Q.; McCreary, D.; Beus, S.G.

    2000-08-01

    The interfacial structure of the two-phase flows is of great importance in view of theoretical modeling and practical applications. In the present study, the focus is made on obtaining detailed local two-phase parameters in the air-water bubbly flow in a rectangular vertical duct using the double-sensor conductivity probe. The characteristic wall-peak is observed in the profiles of the interracial area concentration and the void fraction. The development of the interfacial area concentration along the axial direction of the flow is studied in view of the interfacial area transport and bubble interactions. The experimental data is compared with the drift flux model with C{sub 0} = 1.35.

  10. Bifurcations of a creeping air-water flow in a conical container

    Science.gov (United States)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.; Shtern, Vladimir N.

    2016-10-01

    This numerical study describes the eddy emergence and transformations in a slow steady axisymmetric air-water flow, driven by a rotating top disk in a vertical conical container. As water height Hw and cone half-angle β vary, numerous flow metamorphoses occur. They are investigated for β =30°, 45°, and 60°. For small Hw, the air flow is multi-cellular with clockwise meridional circulation near the disk. The air flow becomes one cellular as Hw exceeds a threshold depending on β . For all β , the water flow has an unbounded number of eddies whose size and strength diminish as the cone apex is approached. As the water level becomes close to the disk, the outmost water eddy with clockwise meridional circulation expands, reaches the interface, and induces a thin layer with anticlockwise circulation in the air. Then this layer expands and occupies the entire air domain. The physical reasons for the flow transformations are provided. The results are of fundamental interest and can be relevant for aerial bioreactors.

  11. Flow Regimes of Air-Water Counterflow Through Cross Corrugated Parallel Plates

    Energy Technology Data Exchange (ETDEWEB)

    de Almeida, V.F.

    2000-06-07

    Heretofore unknown flow regimes of air-water counterflow through a pair of transparent vertical parallel cross corrugated plates were observed via high-speed video. Air flows upward driven by pressure gradient and water, downward driven by gravity. The crimp geometry of the corrugations was drawn from typical corrugated sheets used as filling material in modern structured packed towers. Four regimes were featured, namely, rivulet, bicontinuous, flooding fronts, and flooding waves. It is conceivable that the regimes observed might constitute the basis for understanding how gas and liquid phases contend for available space in the interstices of structured packings in packed towers. Flow regime transitions were expressed in terms of liquid load (liquid superficial velocity) and gas flow factor parameters commonly used in pressure drop and capacity curves. We have carefully examined the range of parameters equivalent to the ill-understood high-liquid-flow operation in packed towers. More importantly, our findings should prove valuable in validating improved first-principles modeling of gas-liquid flows in these industrially important devices.

  12. Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows

    CERN Document Server

    Schmidt, Patrick; Lucquiaud, Mathieu; Valluri, Prashant

    2015-01-01

    We consider the genesis and dynamics of interfacial instability in gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of three main flow parameters (density contrast between liquid and gas, film thickness, pressure drop applied to drive the gas stream) on the interfacial dynamics. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable internal mode for low density contrast. The same linear stability approach provides a quantitative prediction for the onset of (partial) liquid flow reversal in terms of the gas and liquid flow rates. ...

  13. Dynamics of surfactant sorption at the air/water interface: continuous-flow tensiometry.

    Science.gov (United States)

    Svitova, T F; Wetherbee, M J; Radke, C J

    2003-05-01

    Dynamic interfacial tensiometry, gauged by axisymmetric drop shape analysis of static drops or bubbles, provides useful information on surfactant adsorption kinetics. However, the traditional pendant-drop methodology is not readily amenable to the study of desorption kinetics. Thus, the question of sorption reversibility is difficult to assess by this technique. We extend classical pendant/sessile drop dynamic tensiometry by immersing a sessile bubble in a continuously mixed optical cell. Ideal-mixed conditions are established by stirring and by constant flow through the cell. Aqueous surface-active-agent solutions are either supplied to the cell (loading) or removed from the cell by flushing with water (washout), thereby allowing study of both adsorption and desorption kinetics. Well-mixed conditions and elimination of any mass transfer resistance permit direct identification of sorption kinetic barriers to and from the external aqueous phase with time constants longer than the optical-cell residence time. The monodisperse nonionic surfactant ethoxy dodecyl alcohol (C(12)E(5)), along with cationic cetyltrimethyl ammonium bromide (CTAB) in the presence of added salt, adsorbs and desorbs instantaneously at the air/water interface. In these cases, the experimentally observed dynamic-tension curves follow the local-equilibrium model precisely for both loading and washout. Accordingly, these surfactants below their critical micelle concentrations (CMC) exhibit no detectable sorption-activation barriers on time scales of order a min. However, the sorption dynamics of dilute CTAB in the absence of electrolyte is markedly different from that in the presence of KBr. Here CTAB desorption occurs at local equilibrium, but the adsorption rate is kinetically limited, most likely due to an electrostatic barrier arising as the charged surfactant accumulates at the interface. The commercial, polydisperse nonionic surfactant ethoxy nonylphenol (NP9) loads in good agreement with

  14. Experimental Investigation of Spray Evaporation in Turbulent Flow in Countercurrent Humidifier

    Institute of Scientific and Technical Information of China (English)

    王玉璋; 刘永文; 翁史烈

    2004-01-01

    The process in the countercurrent humidifier of HAT cycle involves the evaporation of atomized liquids in a turbulent environment. To allow an optimization of such process and provide data for the validation of numerical calculation, the spray evaporation in a countercurrent air stream was studied experimentally. Measurements were taken for different flow parameters, such as airflow rate and liquid flow rate in order to provide reliable data. Phase-Doppler anemometry (PDA) was applied to obtain the spatial change of the droplet size spectrum in the flow field and to measure droplet size-velocity correlations. These local measured profiles of droplet mean velocities, velocity fluctuations and droplet mean diameters were obtained by averaging over all droplet size classes. Moreover, DualPDA signal processing allows accurate determination of the droplet mass flux and local concentration, from which the global evaporation rates could also be determined. These local temperature profiles were measured using the thermocouple and acquired by data acquisition system based on virtual instrument (VI) technology.

  15. Counter-current flow in a vertical to horizontal tube with obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tye, P.; Matuszkiewicz, A.; Teyssedou, A. [Institut de Genie Nucleaire, Quebec (Canada)] [and others

    1995-09-01

    This paper presents experimental results on counter-current flow and flooding in an elbow between a vertical and a horizontal run. The experimental technique used allowed not only the flooding limit to be determined, but also the entire partial delivery region to be studied as well. The influence that various size orifices placed in the horizontal run have on both the delivered liquid flow rates and on the flooding limits is also examined. It is observed that both the flooding limits and the delivered liquid flow rates decrease with decreasing orifice size. Further, it is also observed that the mechanisms that govern the partial delivery of the liquid are significantly different when an orifice is present in the horizontal leg as compared to the case when no orifice is present.

  16. Co-current air-water flow in downward sloping pipes: Transport of capacity reducing gas pockets in wastewater mains

    NARCIS (Netherlands)

    Pothof, I.W.M.

    2011-01-01

    Air-water flow is an undesired condition in many systems for the transportation of water or wastewater. Air in storm water tunnels may get trapped and negatively affect the system. Air pockets in hydropower tunnels or sewers may cause blow-back events and inadmissible pressure spikes. Water pipes an

  17. Interfacial friction factors for air-water co-current stratified flow in inclined channels

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ki Yong; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    The interfacial shear stress is experimentally investigated for co-current air-water stratified flow in inclined rectangular channels having a length of 1854mm, width of 120 mm and height of 40mm at almost atmospheric pressure. Experiments are carried out in several inclinations from 0 deg up to 10 deg. The local film thickness and the wave height are measured at three locations, i.e., L/H = 8,23, and 40. According to the inclination angle, the experimental data are categorized into two groups; nearly horizontal data group (0 deg {<=} {theta} {<=} 0.7 deg), and inclined channel data group (0.7 deg {<=} {theta} {<=} 10 deg ). Experimental observations for nearly horizontal data group show that the flow is not fully developed due to the water level gradient and the hydraulic jump within the channel. For the inclined channel data group, a dimensionless wave height, {Delta}h/h, is empirically correlated in terms of Re{sub G} and h/H. A modified root-mean-square wave height is proposed to consider the effects of the interfacial and wave propagation velocities. It is found that an equivalent roughness has a linear relationship with the modified root-mean-square wave height and its relationship is independent of the inclination. 10 refs., 6 figs., 1 tab. (Author)

  18. CFD Code Validation against Stratified Air-Water Flow Experimental Data

    Directory of Open Access Journals (Sweden)

    F. Terzuoli

    2008-01-01

    Full Text Available Pressurized thermal shock (PTS modelling has been identified as one of the most important industrial needs related to nuclear reactor safety. A severe PTS scenario limiting the reactor pressure vessel (RPV lifetime is the cold water emergency core cooling (ECC injection into the cold leg during a loss of coolant accident (LOCA. Since it represents a big challenge for numerical simulations, this scenario was selected within the European Platform for Nuclear Reactor Simulations (NURESIM Integrated Project as a reference two-phase problem for computational fluid dynamics (CFDs code validation. This paper presents a CFD analysis of a stratified air-water flow experimental investigation performed at the Institut de Mécanique des Fluides de Toulouse in 1985, which shares some common physical features with the ECC injection in PWR cold leg. Numerical simulations have been carried out with two commercial codes (Fluent and Ansys CFX, and a research code (NEPTUNE CFD. The aim of this work, carried out at the University of Pisa within the NURESIM IP, is to validate the free surface flow model implemented in the codes against experimental data, and to perform code-to-code benchmarking. Obtained results suggest the relevance of three-dimensional effects and stress the importance of a suitable interface drag modelling.

  19. Numerical Modeling of Flow Dynamics in The Aluminum Smelting Process: Comparison Between Air-Water and CO2-Cryolite Systems

    Science.gov (United States)

    Zhao, Zhibin; Feng, Yuqing; Schwarz, M. Philip; Witt, Peter J.; Wang, Zhaowen; Cooksey, Mark

    2017-04-01

    Air-water models have been widely applied as substitutes for CO2-cryolite systems in the study of the complex bubble dynamics and bubble-driven flow that occurs in the molten electrolyte phase in the aluminum electrolytic process, but the detailed difference between the two systems has not been studied. This paper makes a numerical comparison between the bubble dynamics for the two systems. Simulations of both single bubble and continuous bubbling were conducted using a three-dimensional computational fluid dynamics (3D CFD) modeling approach with a volume of fluid (VOF) method to capture the phase interfaces. In the single bubble simulations, it was found that bubbles sliding under an anode in a CO2-cryolite system have a smaller bubble thickness and a higher sliding velocity than those in the air-water system for bubbles of the same volume. Dimensionless analysis and numerical simulation show that contact angle is the dominant factor producing these differences; the effects of kinematic viscosity, surface tension, and density are very small. In the continuous bubbling simulations, the continuous stream of air bubbles detaches from the anode sidewall after a period of climbing, just as it does in the single bubble simulation, but bubbles have less tendency to migrate away from the wall. Quasi-stable state flow characteristics, i.e., time-averaged bath flow pattern, turbulence kinetic energy, turbulence dissipation rate, and gas volume fraction, show a remarkable agreement between the two systems in terms of distribution and magnitude. From the current numerical comparisons, it is believed that the air-water model is a close substitutive model for studying bubble-driven bath flow in aluminum smelting processes. However, because of the difference in bubble morphologies between the two systems, and also the reactive generation and growth of bubbles in the real system, there will likely be some differences in bubble coverage of the anode in the anode-cathode gap.

  20. Numerical Modeling of Flow Dynamics in The Aluminum Smelting Process: Comparison Between Air-Water and CO2-Cryolite Systems

    Science.gov (United States)

    Zhao, Zhibin; Feng, Yuqing; Schwarz, M. Philip; Witt, Peter J.; Wang, Zhaowen; Cooksey, Mark

    2016-12-01

    Air-water models have been widely applied as substitutes for CO2-cryolite systems in the study of the complex bubble dynamics and bubble-driven flow that occurs in the molten electrolyte phase in the aluminum electrolytic process, but the detailed difference between the two systems has not been studied. This paper makes a numerical comparison between the bubble dynamics for the two systems. Simulations of both single bubble and continuous bubbling were conducted using a three-dimensional computational fluid dynamics (3D CFD) modeling approach with a volume of fluid (VOF) method to capture the phase interfaces. In the single bubble simulations, it was found that bubbles sliding under an anode in a CO2-cryolite system have a smaller bubble thickness and a higher sliding velocity than those in the air-water system for bubbles of the same volume. Dimensionless analysis and numerical simulation show that contact angle is the dominant factor producing these differences; the effects of kinematic viscosity, surface tension, and density are very small. In the continuous bubbling simulations, the continuous stream of air bubbles detaches from the anode sidewall after a period of climbing, just as it does in the single bubble simulation, but bubbles have less tendency to migrate away from the wall. Quasi-stable state flow characteristics, i.e., time-averaged bath flow pattern, turbulence kinetic energy, turbulence dissipation rate, and gas volume fraction, show a remarkable agreement between the two systems in terms of distribution and magnitude. From the current numerical comparisons, it is believed that the air-water model is a close substitutive model for studying bubble-driven bath flow in aluminum smelting processes. However, because of the difference in bubble morphologies between the two systems, and also the reactive generation and growth of bubbles in the real system, there will likely be some differences in bubble coverage of the anode in the anode-cathode gap.

  1. Considering the uncertainties in empirical correlations for vertical countercurrent flow limitation (CCFL) with TRACE

    Energy Technology Data Exchange (ETDEWEB)

    Sporn, Michael; Hurtado, Antonio [Technische Univ. Dresden (Germany)

    2015-12-15

    TRACE is used to calculate the thermal-hydraulic sequence in nuclear power plants for accident analysis. In some postulated accidents, countercurrent flow limitation (CCFL) phenomena can occur. This phenomenon is calculated by means of empirical relationships in TRACE. Usually, not all empirical relationships used in TRACE are accessible to the user who develops the computational model for accident analysis, but in the case of CCFL, the user must specify the parameters of the empirical relationship. Additional preliminary work is needed for fitting the parameters so that experimental data matches the computational calculations and the accident analysis can be performed. Furthermore, uncertainties in measurement errors from experimental data lead to user-based variations in the parameters of the empirical relationship for CCFL. Therefore, an alternative procedure in which accident analysis is performed with consideration of the uncertainties in the empirical relationships is presented. The uncertainty was quantified by means of a stochastic linear regression model for the Wallis correlation and the Bankoff correlation. An uncertainty analysis was subsequently performed to demonstrate the influence of uncertainty in certain cases of CCFL.

  2. Verification and Validation of Numerical Models for Air/Water Flow on Coastal and Navigation Fluid-Structure Interaction Applications

    Science.gov (United States)

    Kees, C. E.; Farthing, M.; Dimakopoulos, A.; DeLataillade, T.

    2015-12-01

    Performance analysis and optimization of coastal and navigation structures is becoming feasible due to recent improvements in numerical methods for multiphase flows and the steady increase in capacity and availability of high performance computing resources. Now that the concept of fully three-dimensional air/water flow modelling for real world engineering analysis is achieving acceptance by the wider engineering community, it is critical to expand careful comparative studies on verification,validation, benchmarking, and uncertainty quantification for the variety of competing numerical methods that are continuing to evolve. Furthermore, uncertainty still remains about the relevance of secondary processes such as surface tension, air compressibility, air entrainment, and solid phase (structure) modelling so that questions about continuum mechanical theory and mathematical analysis of multiphase flow are still required. Two of the most popular and practical numerical approaches for large-scale engineering analysis are the Volume-Of-Fluid (VOF) and Level Set (LS) approaches. In this work we will present a publically available verification and validation test set for air-water-structure interaction problems as well as computational and physical model results including a hybrid VOF-LS method, traditional VOF methods, and Smoothed Particle Hydrodynamics (SPH) results. The test set repository and test problem formats will also be presented in order to facilitate future comparative studies and reproduction of scientific results.

  3. An experimental investigation of the interfacial condensation heat transfer in steam/water countercurrent stratified flow in a horizontal pipe

    Energy Technology Data Exchange (ETDEWEB)

    Chu, In Cheol; Yu, Seon Oh; Chun, Moon Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Kim, Byong Sup; Kim, Yang Seok; Kim, In Hwan; Lee, Sang Won [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    An interfacial condensation heat transfer phenomenon in a steam/water countercurrent stratified flow in a nearly horizontal pipe has been experimentally investigated. The present study has been focused on the measurement of the temperature and velocity distributions within the water layer. In particular, the water layer thickness used in the present work is large enough so that the turbulent mixing is limited and the thermal stratification is established. As a result, the thermal resistance of the water layer to the condensation heat transfer is increased significantly. An empirical correlation of the interfacial condensation heat transfer has been developed. The present correlation agrees with the data within {+-} 15%. 5 refs., 6 figs. (Author)

  4. Gas-liquid countercurrent two-phase flow in a PWR hot leg: A comprehensive research review

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto, E-mail: deendarlianto@ugm.ac.id [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2, Yogyakarta 55281 (Indonesia); Hoehne, Thomas; Lucas, Dirk [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Vierow, Karen [Department of Nuclear Engineering Texas A and M University, 129 Zachry Engineering Center, 3133 TAMU College Station, TX 77843-3133 (United States)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We review the scientific progress on the CCFL in a PWR hot leg. Black-Right-Pointing-Pointer It includes the experimental data, one-dimensional and CFD models in the open literatures. Black-Right-Pointing-Pointer The weak and strong points of the published works were clarified. Black-Right-Pointing-Pointer The research directions in this field were proposed. - Abstract: Research into gas-liquid countercurrent two-phase flow in a model of pressurized water reactor (PWR) hot leg has been carried out over the last several decades. An extensive experimental data base has been accumulated from these studies, leading to the development of phenomenological correlations and scaling parameters of the countercurrent flow limitation (CCFL). However, most of the proposed correlations apply under a relatively narrow range of conditions, generally limited to the test section conditions and/or geometry. Moreover the development of mechanistic models based on the underlying physical processes has been limited. In contrast to this mechanistic form of modelling, the implementation of computational fluid dynamics (CFD) techniques has also been pursued, but the considerable robust three-dimensional (3D) closure relations for this application remain an unachieved goal due to lack of detailed phenomenological knowledge and consequent application of empirical one-dimensional experimental correlations to the multidimensional problem. This paper presents a comprehensive review of research work on countercurrent gas-liquid two-phase flow in a PWR hot leg and provides direction regarding future research on this topic. In the introductory section, the problems facing current research are described. In the following sections, recent experimental as well as theoretical research achievements are overviewed. In the last section, the problems that remain unsolved are discussed, along with some concluding remarks. It was found that only limited theoretical

  5. Voidage Measurement of Air-Water Two-phase Flow Based on ERT Sensor and Data Mining Technology

    Institute of Scientific and Technical Information of China (English)

    王保良; 孟振振; 黄志尧; 冀海峰; 李海青

    2012-01-01

    Based on an electrical resistance tomography(ERT) sensor and the data mining technology,a new voidage measurement method is proposed for air-water two-phase flow.The data mining technology used in this work is a least squares support vector machine(LS-SVM) algorithm together with the feature extraction method,and three feature extraction methods are tested:principal component analysis(PCA),partial least squares(PLS) and independent component analysis(ICA).In the practical voidage measurement process,the flow pattern is firstly identified directly from the conductance values obtained by the ERT sensor.Then,the appropriate voidage measurement model is selected according to the flow pattern identification result.Finally,the voidage is calculated.Experimental results show that the proposed method can measure the voidage effectively,and the measurement accuracy and speed are satisfactory.Compared with the conventional voidage measurement methods based on ERT,the proposed method doesn't need any image reconstruction process,so it has the advantage of good real-time performance.Due to the introduction of flow pattern identification,the influence of flow pattern on the voidage measurement is overcome.Besides,it is demonstrated that the LS-SVM method with PLS feature extraction presents the best measurement performance among the tested methods.

  6. Turbulence, aeration and bubble features of air-water flows over macro- and intermediate roughness

    Directory of Open Access Journals (Sweden)

    Stefano PAGLIARA

    2011-06-01

    Full Text Available Free surface flows in macro- and intermediate roughness conditions have a high aeration potential in which the flow characteristics vary with slopes and discharges. The underlying phenomenon of two phase flow characteristics in the macro and intermediate roughness conditions were analyzed in a setup assembled at the PITLAB center of the University of Pisa, Italy. Crushed angular rocks and hemispherical boulders were used to intensify the roughness nature of the bed. Flow discharges per unit width ranging between 0.03 m2/s and 0.09 m2/s and slopes between 0.26 and 0.46 were tested over different arrangements of rough bed. Analyses were mainly concentrated in the inner flow region which constitutes both bubbly and intermediate flow region. The findings revealed that two phase flow properties over rough bed were very much affected by the different rough bed arrangement. Turbulence features of two phase flows over rough beds were compared with that of the stepped chute data under similar flow conditions. Overall the results highlighted the flow features in the inner layers of the two phase flow.

  7. Water temperature effect on upward air-water flow in a vertical pipe: Local measurements database using four-sensor conductivity probes and LDA

    Science.gov (United States)

    Monrós-Andreu, G.; Chiva, S.; Martínez-Cuenca, R.; Torró, S.; Juliá, J. E.; Hernández, L.; Mondragón, R.

    2013-04-01

    Experimental work was carried out to study the effects of temperature variation in bubbly, bubbly to slug transition. Experiments were carried out in an upward air-water flow configuration. Four sensor conductivity probes and LDA techniques was used together for the measurement of bubble parameters. The aim of this paper is to provide a bubble parameter experimental database using four-sensor conductivity probes and LDA technique for upward air-water flow at different temperatures and also show transition effect in different temperatures under the boiling point.

  8. Water temperature effect on upward air-water flow in a vertical pipe: Local measurements database using four-sensor conductivity probes and LDA

    Directory of Open Access Journals (Sweden)

    Hernández L.

    2013-04-01

    Full Text Available Experimental work was carried out to study the effects of temperature variation in bubbly, bubbly to slug transition. Experiments were carried out in an upward air-water flow configuration. Four sensor conductivity probes and LDA techniques was used together for the measurement of bubble parameters. The aim of this paper is to provide a bubble parameter experimental database using four-sensor conductivity probes and LDA technique for upward air-water flow at different temperatures and also show transition effect in different temperatures under the boiling point.

  9. Characteristics of drift-flux models for the 3' diameter vertical-upward air-water flow condition

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, V. T.; Euh, D. J.; Song, C. H. [KAERI, Daejeon (Korea, Republic of)

    2009-07-01

    One of the more complex aspects of two-phase flow calculations is the determination of the void fraction. An accurate estimation of this parameter is important for understanding and predicting the behavior of systems during a wide variety of transient conditions. The drift-flux models are based on correlations to compute the void fraction distribution and slip in a two-phase flow needed to obtain the relative velocity between the phases. Thus, the accuracy of the correlation has a decisive role in determining the correct transport of the two-phases in the system. In this paper, the assessment of 7 correlations based on the Zuber-Findlay model has been done by using the experimental data which were performed on the 3' diameter vertical-upward air-water test facility in KAERI. The void fraction was measured by using the impedance void meter which has a good dynamic resolution to get the values directly without any further data treatment. A total of 28 flow conditions have been performed at 2 bar and 3 bar inlet pressure conditions with temperature of 30 .deg. C, superficial liquid and gas velocity range of 0.5-2.8 m/s and 0.044-1.025 m/s. Some physical phenomena relevant to inlet flow condition and pressure effect were investigated. The results of assessment show a good predictive capability of Bestion model, which is currently used in the system code CATHARE.

  10. The effects of channel diameter on flow pattern, void fraction and pressure drop of two-phase air-water flow in circular micro-channels

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2010-05-15

    Two-phase air-water flow characteristics are experimentally investigated in horizontal circular micro-channels. Test sections are made of fused silica. The experiments are conducted based on three different inner diameters of 0.53, 0.22 and 0.15 mm with the corresponding lengths of 320, 120 and 104 mm, respectively. The test runs are done at superficial velocities of gas and liquid ranging between 0.37-42.36 and 0.005-3.04 m/s, respectively. The flow visualisation is facilitated by systems mainly including stereozoom microscope and high-speed camera. The flow regime maps developed from the observed flow patterns are presented. The void fractions are determined based on image analysis. New correlation for two-phase frictional multiplier is also proposed for practical applications. (author)

  11. Flow pattern, void fraction and pressure drop of two-phase air-water flow in a horizontal circular micro-channel

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Laboratory (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2008-01-15

    Adiabatic two-phase air-water flow characteristics, including the two-phase flow pattern as well as the void fraction and two-phase frictional pressure drop, in a circular micro-channel are experimentally studied. A fused silica channel, 320 mm long, with an inside diameter of 0.53 mm is used as the test section. The test runs are done at superficial velocity of gas and liquid ranging between 0.37-16 and 0.005-3.04 m/s, respectively. The flow pattern map is developed from the observed flow patterns i.e. slug flow, throat-annular flow, churn flow and annular-rivulet flow. The flow pattern map is compared with those of other researchers obtained from different working fluids. The present single-phase experiments also show that there are no significant differences in the data from the use of air or nitrogen gas, and water or de-ionized water. The void fraction data obtained by image analysis tends to correspond with the homogeneous flow model. The two-phase pressure drops are also used to calculate the frictional multiplier. The multiplier data show a dependence on flow pattern as well as mass flux. A new correlation of two-phase frictional multiplier is also proposed for practical application. (author)

  12. Measurement of air distribution and void fraction of an upwards air-water flow using electrical resistance tomography and a wire-mesh sensor

    Science.gov (United States)

    Olerni, Claudio; Jia, Jiabin; Wang, Mi

    2013-03-01

    Measurements on an upwards air-water flow are reported that were obtained simultaneously with a dual-plane electrical resistance tomograph (ERT) and a wire-mesh sensor (WMS). The ultimate measurement target of both ERT and WMS is the same, the electrical conductivity of the medium. The ERT is a non-intrusive device whereas the WMS requires a net of wires that physically crosses the flow. This paper presents comparisons between the results obtained simultaneously from the ERT and the WMS for evaluation and calibration of the ERT. The length of the vertical testing pipeline section is 3 m with an internal diameter of 50 mm. Two distinct sets of air-water flow rate scenarios, bubble and slug regimes, were produced in the experiments. The fast impedance camera ERT recorded the data at an approximate time resolution of 896 frames per second (fps) per plane in contrast with the 1024 fps of the wire-mesh sensor WMS200. The set-up of the experiment was based on well established knowledge of air-water upwards flow, particularly the specific flow regimes and wall peak effects. The local air void fraction profiles and the overall air void fraction were produced from two systems to establish consistency for comparison of the data accuracy. Conventional bulk flow measurements in air mass and electromagnetic flow metering, as well as pressure and temperature, were employed, which brought the necessary calibration to the flow measurements. The results show that the profiles generated from the two systems have a certain level of inconsistency, particularly in a wall peak and a core peak from the ERT and WMS respectively, whereas the two tomography instruments achieve good agreement on the overall air void fraction for bubble flow. For slug flow, when the void fraction is over 30%, the ERT underestimates the void fraction, but a linear relation between ERT and WMS is still observed.

  13. Quantitative measurement of size and three-dimensional position of fast-moving bubbles in air-water mixture flows using digital holography.

    Science.gov (United States)

    Tian, Lei; Loomis, Nick; Domínguez-Caballero, José A; Barbastathis, George

    2010-03-20

    We present a digital in-line holographic imaging system for measuring the size and three-dimensional position of fast-moving bubbles in air-water mixture flows. The captured holograms are numerically processed by performing a two-dimensional projection followed by local depth estimation to quickly and efficiently obtain the size and position information of multiple bubbles simultaneously. Statistical analysis on measured bubble size distributions shows that they follow lognormal or gamma distributions.

  14. Study on two-phase countercurrent flow and transport phenomenon in PEM of a direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    WANG; Jiang; SHI; Mingheng

    2006-01-01

    Based on the requirement of water management for a direct methanol fuel cell, this paper analyzes qualitatively the mechanism of occurrence and development of a two-phase countercurrent flow with corresponding transport phenomenon in the PEM. A one-dimensional, steady state quantitative model of heat and mass transfer in internal volumetric ohmic heating porous media saturated by liquid and vapor phases is developed. The effects of capillarity, electro-osmotic drag and phase change are included. Two important formulas to calculate the theoretical length of two-phase zone δt and determine the critical criterion |-ω/γ|cr for dryout in PEM are deduced. By use of these two dimensionless parameters, dryout of PEM can be easily predicted. Theoretical temperature, pressure and saturation profiles within the two-phase region are obtained numerically, which can help to explore the performance of a DMFC operating in its ohmic polarization region. The simulation results can be used to determine the catalyst content of cathode catalyst layer and the corresponding optimal thickness of PEM.

  15. Production of carbonaceous adsorbents from agricultural by-products and novolac resin under a continuous countercurrent flow type pyrolysis operation.

    Science.gov (United States)

    Ioannou, Z; Simitzis, J

    2013-02-01

    Carbonaceous adsorbents based on novolac resin (N) and olive stone biomass (B) in a proportion of 20/80 and 40/60 w./w. N/O were produced. The specimens were cured (c) and pyrolyzed/carbonized (C) up to 1000 °C under a continuous countercurrent flow type pyrolysis operation (N20B-cC, N40B-cC). Commercial activated carbon (AC) was used for comparison reasons. Methylene blue adsorption from its aqueous solutions onto the adsorbents and kinetic analysis were investigated. The specific surface area of adsorbents and the gross calorific values (GCV) of cured materials were determined. The results show that N40B-cC presents lower weight loss and shrinkage but higher methylene blue adsorption than N20B-cC. Pseudo-second order mechanism describes better methylene blue adsorption onto all adsorbents. The specific surface area of carbonaceous and the gross calorific values of cured materials follow the order: AC>N20B-cC>N40B-cC and N100-c>N40B-c>N20B-c>B respectively. Olive stone biomass may constitute a suitable precursor for the production of carbonaceous materials.

  16. The Calculated Ratio of the Gas Flow in a Countercurrent Cyclone Dust Concentrator

    Directory of Open Access Journals (Sweden)

    Vasilevsky Michail

    2016-01-01

    Full Text Available There are numerous studies of the structure of swirling flow in a variety of devices in which the peculiarities of the parameters associated with the twist flow. The values of the local parameters of the twist of the axial direction are experimentally and connect them with a constructive twist parameter, which is built from the idealized repose of the gas flow in vortex distribution and speed at the exit of the swirl. For counter flow chamber is the equation for the input pulse in the radial direction and the twist parameter is provided in the radial direction. It allows us to estimate the maximum radius of the circumferential velocity not only near the outlet, but also near the end surface of the chamber. On a cylindrical surface with a radius of outlet cyclone tangential turbulent friction in the radial direction depends on the product of a circle and radial speeds. Compiled equation changes the flow of angular momentum in the axial zone, depending on the force of friction tangential flow on the surface with the radius of the outlet pipe of the cyclone. This equation allowed assessing the circulation of gas in the axial zone.

  17. The Effect of Sudden Change in Pipe Diameter on Flow Patterns of Air-Water Two-Phase

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Flow patterns upstream and downstream of a sudden-contraction cross-section in a vertical straight pipe were presented. By comparing with flow patterns in uniform croes-section vertical tubes, the effect of the sudden change in pipe diameter on flow patterns was analyzed. Flow pattern transition mechanisms were discussed and transition criteria for flow pattern transitions were deduced accordingly using the dimensional analysis.

  18. Implications of surfactant-induced flow for miscible-displacement estimation of air-water interfacial areas in unsaturated porous media.

    Science.gov (United States)

    Costanza-Robinson, Molly S; Zheng, Zheng; Henry, Eric J; Estabrook, Benjamin D; Littlefield, Malcolm H

    2012-10-16

    Surfactant miscible-displacement experiments represent a conventional means of estimating air-water interfacial area (A(I)) in unsaturated porous media. However, changes in surface tension during the experiment can potentially induce unsaturated flow, thereby altering interfacial areas and violating several fundamental method assumptions, including that of steady-state flow. In this work, the magnitude of surfactant-induced flow was quantified by monitoring moisture content and perturbations to effluent flow rate during miscible-displacement experiments conducted using a range of surfactant concentrations. For systems initially at 83% moisture saturation (S(W)), decreases of 18-43% S(W) occurred following surfactant introduction, with the magnitude and rate of drainage inversely related to the surface tension of the surfactant solution. Drainage induced by 0.1 mM sodium dodecyl benzene sulfonate, commonly used for A(I) estimation, resulted in effluent flow rate increases of up to 27% above steady-state conditions and is estimated to more than double the interfacial area over the course of the experiment. Depending on the surfactant concentration and the moisture content used to describe the system, A(I) estimates varied more than 3-fold. The magnitude of surfactant-induced flow is considerably larger than previously recognized and casts doubt on the reliability of A(I) estimation by surfactant miscible-displacement.

  19. Investigation of Countercurrent Helium-Air Flows in Air-ingress Accidents for VHTRs

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaodong; Christensen, Richard; Oh, Chang

    2013-10-03

    The primary objective of this research is to develop an extensive experimental database for the air- ingress phenomenon for the validation of computational fluid dynamics (CFD) analyses. This research is intended to be a separate-effects experimental study. However, the project team will perform a careful scaling analysis prior to designing a scaled-down test facility in order to closely tie this research with the real application. As a reference design in this study, the team will use the 600 MWth gas turbine modular helium reactor (GT-MHR) developed by General Atomic. In the test matrix of the experiments, researchers will vary the temperature and pressure of the helium— along with break size, location, shape, and orientation—to simulate deferent scenarios and to identify potential mitigation strategies. Under support of the Department of Energy, a high-temperature helium test facility has been designed and is currently being constructed at Ohio State University, primarily for high- temperature compact heat exchanger testing for the VHTR program. Once the facility is in operation (expected April 2009), this study will utilize high-temperature helium up to 900°C and 3 MPa for loss-of-coolant accident (LOCA) depressurization and air-ingress experiments. The project team will first conduct a scaling study and then design an air-ingress test facility. The major parameter to be measured in the experiments is oxygen (or nitrogen) concentration history at various locations following a LOCA scenario. The team will use two measurement techniques: 1) oxygen (or similar type) sensors employed in the flow field, which will introduce some undesirable intrusiveness, disturbing the flow, and 2) a planar laser-induced fluorescence (PLIF) imaging technique, which has no physical intrusiveness to the flow but requires a transparent window or test section that the laser beam can penetrate. The team will construct two test facilities, one for high-temperature helium tests with

  20. Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hideo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-05-01

    The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs.

  1. Visualization of the boiling phenomena and counter-current flow limit of annular heat pipe

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2015-10-15

    The thermal resistance of conventional heat pipes increases over the capillary limit because of the insufficient supplement of the working fluid. Due to the shortage of the liquid supplement, thermosyphon is widely used for vertically oriented heat transport and high heat load conditions. Thermosyphons are two-phase heat transfer devices that have the highly efficient heat transport from evaporation to condensation section that makes an upward driving force for vapor. In the condenser section, the vapor condenses and releases the latent heat. Due to the gravitation force acting on the liquid in the tube, working fluid back to the evaporator section, normally this process operate at the vertical and inclination position. The use of two-phase closed thermosyphon (TPCT) for the cooling devices has the limitation due to the phase change of the working fluid assisted by gravity force. Due to the complex phenomenon of two-phase flow, it is required to understand what happened in TPCT. The visualization of the thermosyphon and heat pipe is investigated for the decrease of thermal resistance and enhancement of operation limit. Weibel et al. investigated capillary-fed boiling of water with porous sintered powder wick structure using high speed camera. At the high heat flux condition, dry-out phenomenon and a thin liquid film are observed at the porous wick structure. Wong and Kao investigated the evaporation and boiling process of mesh wicked heat pipe using optical camera. At the high heat flux condition, the water filing became thin and partial dry-out was observed in the evaporator section. Our group suggested the concept of a hybrid heat pipe with control rod as Passive IN-core Cooling System (PINCs) for decay heat removal for advanced nuclear power plant. The hybrid heat pipe is the combination of the heat pipe and control rod. It is necessary for PINCs to contain a neutron absorber (B{sub 4}C) to have the ability of reactivity control. It has annular vapor space and

  2. 3-Dimensional numerical study of cooling performance of a heat sink with air-water flow through mini-channel

    Science.gov (United States)

    Majumder, Sambit; Majumder, Abhik; Bhaumik, Swapan

    2016-07-01

    The present microelectronics market demands devices with high power dissipation capabilities having enhanced cooling per unit area. The drive for miniaturizing the devices to even micro level dimensions is shooting up the applied heat flux on such devices, resulting in complexity in heat transfer and cooling management. In this paper, a method of CPU processor cooling is introduced where active and passive cooling techniques are incorporated simultaneously. A heat sink consisting of fins is designed, where water flows internally through the mini-channel fins and air flows externally. Three dimensional numerical simulations are performed for large set of Reynolds number in laminar region using finite volume method for both developing flows. The dimensions of mini-channel fins are varied for several aspect ratios such as 1, 1.33, 2 and 4. Constant temperature (T) boundary condition is applied at heat sink base. Channel fluid temperature, pressure drop are analyzed to obtain best cooling option in the present study. It has been observed that as the aspect ratio of the channel decreases Nusselt number decreases while pressure drop increases. However, Nusselt number increases with increase in Reynolds number.

  3. Experimental investigation of countercurrent flow limitation (CCFL) in a large-diameter hot-leg geometry: A detailed description of CCFL mechanisms, flow patterns and high-quality HSC imaging of the interfacial structure in a 1/3.9 scale of PWR geometry

    Energy Technology Data Exchange (ETDEWEB)

    Al Issa, S., E-mail: salissa.email@gmail.com; Macian-Juan, R.

    2014-12-15

    Highlights: • Countercurrent flow limitation is experimentally investigated in a large-diameter hot-leg pipe geometry (D{sub in} = 190 mm, ∼1/3.9 scale of a PWR hot-leg). • High-speed and high-quality imaging was implemented to study the interfacial structure and flow patterns during flooding and deflooding. • Two main mechanisms were identified and described in details: bend-CCFL and ADE-CCFL. Four regions were recognized for j{sub water,in}{sup *0.5}=0.085−0.305.. • Experimental curves of the onset of CCFL, and deflooding were discussed. High-quality images provide valuable validation data for CFD. • Form a safety point of view: onset of ADE-CCFL precedes the onset of bend-CCFL and its influence cannot be neglected for j{sub water,in}{sup *0.5}>0.27.. - Abstract: Countercurrent flow limitation (CCFL) is experimentally investigated in large-diameter hot-leg geometry. COLLIDER test facility consists of reactor vessel simulator (RVs), hot-leg pipe, and a steam generator simulator (SGs) and was constructed to be a 1/3.9 scale model of a real PWR geometry. The facility is completely transparent providing excellent conditions for optical observation of the gas/liquid interface. Experiments were performed at atmospheric pressure using air/distilled water as flow mediums. High-quality high speed recording (HSC) was implemented to acquire the air/water interface which provided a unique and detailed look into the interface structure within the entire hot-leg geometry. This allowed a precise and a high-qualitative identification and description of the flow patterns and mechanisms by which the onset of CCFL occurs. A systematic experimental investigation of the onset of CCFL and deflooding was carried out for water inlet velocities in the range J{sub w,in}{sup *0.5}=0.085−0.305,ΔJ{sub w,in}{sup *0.5}=0.01. Air velocity was increased and decreased stepwise to identify the onset of CCFL and deflooding limits precisely. Two onset of CCFL mechanisms were

  4. Experimental Characterisation of the Interfacial Structure during Counter-Current Flow Limitation in a Model of the Hot Leg of a PWR

    Directory of Open Access Journals (Sweden)

    Christophe Vallée

    2012-01-01

    Full Text Available In order to investigate the two-phase flow behaviour during counter-current flow limitation in the hot leg of a pressurised water reactor, dedicated experiments were performed in a scaled down model of Kobe University. The experiments were performed with air and water at atmospheric pressure and room temperature. At high flow rates, CCFL occurs and the discharge of water to the reactor pressure vessel simulator is limited by the formation of slugs carrying liquid back to the steam generator. The structure of the interface was observed from the side of the channel test section using a high-speed video camera. An algorithm was developed to recognise the stratified interface in the camera frames after background subtraction. This method allows extracting the water level at any position in the image as well as performing further statistical treatments. The evolution of the interfacial structure along the horizontal part of the hot leg is shown by the visualisation of the probability distribution of the water level and analysed in function of the liquid and gas flow rates. The data achieved are useful for the analysis of the flow conditions as well as for the validation of modelling approaches like computational fluid dynamics.

  5. Air/Water Purification

    Science.gov (United States)

    1992-01-01

    After 18 years of research into air/water pollution at Stennis Space Center, Dr. B. C. Wolverton formed his own company, Wolverton Environmental Services, Inc., to provide technology and consultation in air and water treatment. Common houseplants are used to absorb potentially harmful materials from bathrooms and kitchens. The plants are fertilized, air is purified, and wastewater is converted to clean water. More than 100 U.S. communities have adopted Wolverton's earlier water hyacinth and artificial marsh applications. Catfish farmers are currently evaluating the artificial marsh technology as a purification system.

  6. Study of Co-Current and Counter-Current Gas-Liquid Two-Phase Flow Through Packed Bed in Microgravity

    Science.gov (United States)

    Revankar, Shripad T.

    2002-11-01

    The main goal of the project is to obtain new experimental data and development of models on the co-current and counter-current gas-liquid two-phase flow through a packed bed in microgravity and characterize the flow regime transition, pressure drop, void and interfacial area distribution, and liquid hold up. Experimental data will be obtained for earth gravity and microgravity conditions. Models will be developed for the prediction of flow regime transition, void fraction distribution and interfacial area concentration, which are key parameters to characterize the packed bed performance. Thus the specific objectives of the proposed research are to: (1) Develop experiments for the study of the gas liquid two-phase flow through the packed bed with three different flow combinations: co-current down flow, co-current upflow and counter current flow. (2) Develop pore scale and bed scale two-phase instrumentation for measurement of flow regime transition, void distribution and gas-liquid interfacial area concentration in the packed bed. (3) Obtain database on flow regime transition, pressure drop, void distribution, interfacial area concentration and liquid hold up as a function of bed characteristics such as bed particle size, porosity, and liquid properties such as viscosity and surface tension. (4) Develop mathematical model for flow regime transition, void fraction distribution and interfacial area concentration for co-current gas-liquid flow through the porous bed in gravity and micro gravity conditions.(4) Develop mathematical model for the flooding phenomena in counter-current gas-liquid flow through the porous bed in gravity and micro gravity conditions. The present proposal addresses the most important topic of HEDS-specific microgravity fluid physics research identified by NASA 's one of the strategic enterprises, OBPR Enterprise. The proposed project is well defined and makes efficient use of the ground-based parabolic flight research aircraft facility. The

  7. Flow patterns and their transition characteristicsof the air-water two-phase flow in a horizontal pipe with asudden-changed cross-section area

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Flow patterns in upstream and downstream straight tubes of sudden-changedareas in ahorizontal straight pipe were experimentally examined. Both sudden-expansioncross-section (SECS)and sudden-contraction cross-section (SCCS) were investigated. The flow pattern mapsupstream anddownstream were delineated and compared with those in straight tubes with uniformcross-sections.The effects of the SECS and SCCS on flow patterns were discussed and analyzed.Furthermore, flowpattern transition mechanisms resulting in occurrences of different flow patternswere simplydiscussed and some transition criteria for the flow pattern transitions were deduced byusing the non-dimensionlized analysis method.

  8. Measurement of Gas and Liquid Velocities in an Air-Water Two-Phase Flow using Cross-Correlation of Signals from a Double Senor Hot-Film Probe

    Energy Technology Data Exchange (ETDEWEB)

    B. Gurau; P. Vassalo; K. Keller

    2002-02-19

    Local gas and liquid velocities are measured by cross-correlating signals from a double sensor hot-film anemometer probe in pure water flow and air water two-phase flow. The gas phase velocity measured in two-phase flow agrees with velocity data obtained using high-speed video to within +/-5%. A turbulent structure, present in the liquid phase, allows a correlation to be taken, which is consistent with the expected velocity profiles in pure liquid flow. This turbulent structure is also present in the liquid phase of a two-phase flow system. Therefore, a similar technique can be applied to measure the local liquid velocity in a two-phase system, when conditions permit.

  9. A Laboratory Exercise Using a Physical Model for Demonstrating Countercurrent Heat Exchange

    Science.gov (United States)

    Loudon, Catherine; Davis-Berg, Elizabeth C.; Botz, Jason T.

    2012-01-01

    A physical model was used in a laboratory exercise to teach students about countercurrent exchange mechanisms. Countercurrent exchange is the transport of heat or chemicals between fluids moving in opposite directions separated by a permeable barrier (such as blood within adjacent blood vessels flowing in opposite directions). Greater exchange of…

  10. Analytical Investigation by Using the Two-fluid-model to Study the Interfacial Behavior of Air-water Horizontal Stratified Flow

    CERN Document Server

    Kuntoro, Hadiyan Yusuf; Indarto,

    2015-01-01

    In the chemical, petroleum and nuclear industries, pipelines are often used to transport fluids from one process site to another one. The understanding of the fluids behavior inside the pipelines is the most important consideration for the engineers and scientists. From the previous studies, there are several two-phase flow patterns in horizontal pipe. One of them is stratified flow pattern, which is characterized by the liquid flowing along the bottom of the pipe and the gas moving above it cocurrently. Another flow patterns are slug and plug flow patterns. This kind of flow triggers the damage in pipelines, such as corrosion, abrasion, and blasting pipe. Therefore, slug and plug flow patterns are undesirable in pipelines, and the flow is maintained at the stratified flow condition for safety reason. In this paper, the analytical-based study on the experiment of the stratified flow pattern in a 26 mm i.d. horizontal pipe is presented. The experiment is performed to develop a high quality database of the stra...

  11. Study of counter current flow limitation model of MARS-KS and SPACE codes under Dukler's air/water flooding test conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Woong; Kim, Min Gil; Lee, Jeong Ik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Bang, Young Seok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    In particular, CCFL(the counter current flow limitation) occurs in components such as hot leg, downcomer annulus and steam generator inlet plenum during LOCA which is possible to have flows in two opposite directions. Therefore, CCFL is one of the thermal-hydraulic models which has significant effect on the reactor safety analysis code performance. In this study, the CCFL model will be evaluated with MARS-KS based on two-phase two-field governing equations and SPACE code based on two-phase three-field governing equations. This study will be conducted by comparing MARS-KS code which is being used for evaluating the safety of a Korean Nuclear Power Plant and SPACE code which is currently under assessment for evaluating the safety of the designed nuclear power plant. In this study, comparison of the results of liquid upflow and liquid downflow rate for different gas flow rate from two code to the famous Dukler's CCFL experimental data are presented. This study will be helpful to understand the difference between system analysis codes with different governing equations, models and correlations, and further improving the accuracy of system analysis codes. In the nuclear reactor system, CCFL is an important phenomenon for evaluating the safety of nuclear reactors. This is because CCFL phenomenon can limit injection of ECCS water when CCFL occurs in components such as hot leg, downcomer annulus or steam generator inlet plenum during LOCA which is possible to flow in two opposite directions. Therefore, CCFL is one of the thermal-hydraulic models which has significant effect on the reactor safety analysis code performance. In this study, the CCFL model was evaluated with MARS-KS and SPACE codes for studying the difference between system analysis codes with different governing equations, models and correlations. This study was conducted by comparing MARS-KS and SPACE code results of liquid upflow and liquid downflow rate for different gas flow rate to the famous Dukler

  12. Pore-scale characteristics of multiphase flow in porous media: A comparison of air-water and oil-water experiments

    DEFF Research Database (Denmark)

    Culligan, K.A.; Wildenschild, Dorthe; Christensen, Britt Stenhøj Baun;

    2006-01-01

    determinant of NAPL removal efficiency. To measure the interfacial area, we have used a synchrotron-based CMT technique to obtain high-resolution 3D images of flow in a Soltrol-water glass bead system. The interfacial area is found to increase as the wetting phase saturation decreases, reach a maximum...

  13. Anisotropic diffusion of volatile pollutants at air-water interface

    Institute of Scientific and Technical Information of China (English)

    Li-ping CHEN; Jing-tao CHENG; Guang-fa DENG

    2013-01-01

    The volatile pollutants that spill into natural waters cause water pollution. Air pollution arises from the water pollution because of volatilization. Mass exchange caused by turbulent fluctuation is stronger in the direction normal to the air-water interface than in other directions due to the large density difference between water and air. In order to explore the characteristics of anisotropic diffusion of the volatile pollutants at the air-water interface, the relationship between velocity gradient and mass transfer rate was established to calculate the turbulent mass diffusivity. A second-order accurate smooth transition differencing scheme (STDS) was proposed to guarantee the boundedness for the flow and mass transfer at the air-water interface. Simulations and experiments were performed to study the trichloroethylene (C2HCl3) release. By comparing the anisotropic coupling diffusion model, isotropic coupling diffusion model, and non-coupling diffusion model, the features of the transport of volatile pollutants at the air-water interface were determined. The results show that the anisotropic coupling diffusion model is more accurate than the isotropic coupling diffusion model and non-coupling diffusion model. Mass transfer significantly increases with the increase of the air-water relative velocity at a low relative velocity. However, at a higher relative velocity, an increase in the relative velocity has no effect on mass transfer.

  14. Anisotropic diffusion of volatile pollutants at air-water interface

    Directory of Open Access Journals (Sweden)

    Li-ping CHEN

    2013-04-01

    Full Text Available The volatile pollutants that spill into natural waters cause water pollution. Air pollution arises from the water pollution because of volatilization. Mass exchange caused by turbulent fluctuation is stronger in the direction normal to the air-water interface than in other directions due to the large density difference between water and air. In order to explore the characteristics of anisotropic diffusion of the volatile pollutants at the air-water interface, the relationship between velocity gradient and mass transfer rate was established to calculate the turbulent mass diffusivity. A second-order accurate smooth transition differencing scheme (STDS was proposed to guarantee the boundedness for the flow and mass transfer at the air-water interface. Simulations and experiments were performed to study the trichloroethylene (C2HCl3 release. By comparing the anisotropic coupling diffusion model, isotropic coupling diffusion model, and non-coupling diffusion model, the features of the transport of volatile pollutants at the air-water interface were determined. The results show that the anisotropic coupling diffusion model is more accurate than the isotropic coupling diffusion model and non-coupling diffusion model. Mass transfer significantly increases with the increase of the air-water relative velocity at a low relative velocity. However, at a higher relative velocity, an increase in the relative velocity has no effect on mass transfer.

  15. Countercurrent aortography via radial artery

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Hyung Kuk; Lee, Young Chun; Lee, Seung Chul; Jeon, Seok Chol; Joo, Kyung Bin; Lee, Seung Ro; Kim, Soon Yong [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

    1987-06-15

    Countercurrent aortography via radial artery was performed for detection of aortic arch anomalies in 4 infants with congenital heart disease. Author's cases of aortic arch anomalies were 3 cases of PDA, 1 case of coarctation of aorta, and 1 case of occlusion of anastomosis site on subclavian artery B-T shunt. And aberrant origin of the right SCA, interrupted aortic arch, hypoplastic aorta, anomalous origin of the right pulmonary artery from the ascending aorta can be demonstrated by this method. Countercurrent aortography affords an safe and simple method for detection of aortic arch anomalies without retrograde arterial catheterization, especially in small infants or premature babies.

  16. Local heat transfer properties in co- and counter-current G-L-S magnetically stabilized fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Jinli Zhang; Ming Zhang; Wei Li; Xiaofang Li; Xiangkun Meng; Baoning Zong

    2011-01-01

    Heat transfer coefficients were measured by immersed probes in co- and counter-current G-L-S magnetically stabilized fluidized beds (MSFBs) using air,water and nickel-alloy particles as the gas,liquid and solid phases. Influences of major factors,including magnetic field intensity,superficial gas and liquid velocities,liquid viscosity and surface tension,on heat-transfer properties were studied experimentally,indicating that both co- and counter-current G-L-S MSFB can provide relatively uniform radial distribution of heat transfer coefficients under appropriate operation conditions,thus controlling operation temperature for highly exothermic multi-phase reaction systems. Two correlations were provided to estimate accurately heat transfer properties in both co- and counter-current G-L-S MSFB systems,with an average error of less than 10%.

  17. Recent progress on countercurrent chromatography modeling

    OpenAIRE

    Wang, Fengkang; Ito, Yoichiro; Wei, Yun

    2014-01-01

    As countercurrent chromatography is becoming an established method in chromatography for many kinds of products, it is becoming increasingly important to model the process and to be able to predict the peaks for a given process. The CCC industries are looking for rapid methods to analyze the processes of countercurrent chromatography and select suitable solvent system. In this paper, recent progress is reviewed in the development and demonstration of several types of models of countercurrent ...

  18. The Effect of Sudden Change in Pipe Diameter on Flow Patterns of Air-Water Two-Phase Flow in Vertical Pipe (Ⅱ) Sudden-Expansion Cross-Section

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns in uniform cross-section vertical tubes. It is found the effect is great. There exist great instabilities of two-phase flow in the neighboring areas of the SECS both downstream and upstream.

  19. Research and Application Progress in Countercurrent Solvent Extraction

    Institute of Scientific and Technical Information of China (English)

    贾江涛; 吴声; 廖春生; 严纯华

    2004-01-01

    In this article, the recent progress made by Peking University is briefly introduced. Based on Theory of Countercurrent Extraction established by Prof. Guangxian Xu, the static equilibrium and dynamic process for two- and three-outlet countercurrent extractions, and designed the optimized parameters for the real cascades to separate different rare earth minerals, which can be scaled-up to the industrial process without any further experimental verification were systematically investigated. In order to stabilize the quality of products and improve the capability of automation for extraction process, we have also established an 241Am stimulated X-ray fluorescent energy dispersive method to detect the elemental composition in both organic and aqueous phases, which can be used as an on-line analysis method in practice. Furthermore, the expert system and the control software with open- and close-loop models have been set up. Combined with the detected data from on-line analysis, the flow-rates of extracting, feeding, scrubbing and stripping solutions can be controlled in an optimum status for the industrial cascades. In addition, we have developed a new multi-input and multi-output countercurrent extraction process for separating multi-component rare earth mixture with lower chemical cost and pollution.

  20. Interfacial structure in an air-water planar bubble jet

    Science.gov (United States)

    Sun, X.; Vasavada, S.; Choi, S. W.; Kim, S.; Ishii, M.; Beus, S. G.

    2005-04-01

    The objective of the current study is to better understand the interfacial structure and its development in an air-water planar bubble jet, as well as to provide a unique benchmark data set for a 3D thermal-hydraulic analysis code. Both flow visualization and local measurements were performed in three characteristic flow conditions at four elevations along a test section with a cross section of 200 mm in width and 10 mm in gap. A high-speed digital video camera was applied in the flow visualization study to capture the flow structures and bubble interaction phenomena, while a miniaturized four-sensor conductivity probe was used to acquire the time-averaged local void fraction, interfacial velocity, and bubble number frequency. Also, the interfacial area concentration and the averaged bubble Sauter mean diameter were obtained from the local measurements. The lateral bubble transport and bubble interaction mechanisms were clearly demonstrated in the acquired data.

  1. 波节管纵向逆流换热性能的三维数值模拟研究%3D Numerical Simulation Investigation of Heat Transfer Performance for Vertical Countercurrent Flow in Corrugated Tube

    Institute of Scientific and Technical Information of China (English)

    金铁石; 付崇彬

    2012-01-01

    In this article, the 3D k - e Model numerical simulation is adopted to research heat transfer and frictional characteristic of the vertical countercurrent flow in corrugated tube. The working medium was helium and nitrogen in the tube side and shell side respectively. The tube bundle has used triangular arrangement. The paper has first analyzed the impact of different wave distance and Reynolds number on heat transfer rate. At the same time, the impact of different wave distance and Reynolds number on Q/Qo (heat transfer ratio between smooth and corrugated tube) and △p/△po(pressure loss ratio between smooth and corrugated) were also analyzed in order to emphasize the superiority of corrugated tube. It was found that the heat transfer and frictional characteristic of corrugated tube have decreased with the increasing of wave length, whereas the overall heat transfer performance has been improved. On the contrary, the Reynolds number has the opposite effect.%本文基于k-ε模型,针对波节管高效换热元件中纵向逆流换热的传热特性和阻力特性进行三维数值模拟研究.传热工质在管程和壳程分别为氦气和氮气,管束采用三角形布置.本文首先分析了不同波距及雷诺数下对换热量影响.为了体现高效换热元件比光管的优越性,随后分析了不同波距及雷诺数对Q/Qo(波节管与光管的换热量比)与△p/△Po(波节管与光管的压力降比).最后得出结论,波距L的增加使高效换热元件的传热性能和阻力性能有所降低,但提高了其综合传热性能.雷诺数的增加会大幅提高换热量,但同时综合传热效率也大幅降低.

  2. Summertime Subtropical Countercurrent on isopycnals in the western North Pacific

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Circulations on isopycnals (σrθ) in the western North Pacific were investigated by using P-vector method;the data were taken from the U.S. Navy's climatological temperature and salinity dataset (public domain) with 1/2°×1/2° resolution. Results not only show the main circulation systems on isopycnals in the western North Pacific such as the North Equatorial Current (NEC), Kuroshio and Kuroshio Countercurrent, but also reveal the Subtropical Countercurrent (STCC) clearly. In this note we pay attention to discussing the distribution of STCC in summer (in June).The STCC flows eastward along a winding road; on shallow isopycnals, the STCC originates from the area east of Bashi Strait at about 122.5°E; with the isopycnals increasing, the origin and flow core of STCC move to north and east, but the main part of STCC is still between 18° and 23.5°N, i.e.near the Tropic of Cancer. There exists STCC on all isopycnals between the sea surface and 25.8 σθThe current vectors of STCC on isopycnais are shown for the first time, and the distribution of the potential vorticity indicates that STCC is just overlying the southern boundary of the Subtropical Mode Water (STMW).``

  3. Solvent System Selection Strategies in Countercurrent Separation

    Science.gov (United States)

    Liu, Yang; Friesen, J. Brent; McAlpine, James B.; Pauli, Guido F.

    2015-01-01

    The majority of applications in countercurrent and centrifugal partition chromatography, collectively known as countercurrent separation, are dedicated to medicinal plant and natural product research. In countercurrent separation, the selection of the appropriate solvent system is of utmost importance as it is the equivalent to the simultaneous choice of column and eluent in liquid chromatography. However, solvent system selection is often laborious, involving extensive partition and/or analytical trials. Therefore, simplified solvent system selection strategies that predict the partition coefficients and, thus, analyte behavior are in high demand and may advance both the science of countercurrent separation and its applications. The last decade of solvent system selection theory and applications are critically reviewed, and strategies are classified according to their data input requirements. This offers the practitioner an up-to-date overview of rationales and methods for choosing an efficient solvent system, provides a perspective regarding their accuracy, reliability, and practicality, and discusses the possibility of combining multiple methods for enhanced prediction power. PMID:26393937

  4. Investigations of hydraulic operating conditions of air lift pump with three types of air-water mixers

    Directory of Open Access Journals (Sweden)

    Kalenik Marek

    2015-03-01

    Full Text Available Investigations of hydraulic operating conditions of air lift pump with three types of air-water mixers. The paper presents the analysis of results of the investigations concerning the influence of various constructive solutions of the air-water mixers on hydraulic operating conditions of the air lift pump. The scope of the investigations encompassed the determination of characteristics of delivery head and delivery rate for three types of air-water mixers applied in the constructed air lift pump. Using the obtained results, the efficiency of the three types of air-water mixers applied in this air lift pump was determined. The analysis was carried out and there was checked whether the improved analytical Stenning-Martin model can be used to design air lift pumps with the air-water mixers of these types. The highest capacity in the water transport was reached by the air lift pump with the 1st type air-water mixer, the lowest one – with the 3rd type air-water mixer. The water flow in the air lift pump increases along with the rise in the air flow. The lower are the hydraulic losses generated during flow of the air flux by the air-water mixer, the higher is the air lift pump capacity. Along with the rise in the water delivery head, the capacity of the air lift pump decreases. The highest efficiency is reached by the air lift pump with the 1st type air-water mixer, the lowest – with the 3st type air-water mixer. The efficiency of the air lift pump for the three investigated types of air-water mixers decreases along with the rise in air flow rate and water delivery head. The values of submergence ratio (h/L of the delivery pipe, calculated with the use of the improved analytical Stenning-Martin model, coincide quite well with the values of h/L determined from the measurements.

  5. Measurement of the local void fraction in two-phase air-water flow with a hot-film anemometer; Mesure du taux de vide local en ecoulement diphasique eau-air par un anemometre a film chaud

    Energy Technology Data Exchange (ETDEWEB)

    Delhaye, J. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1968-07-01

    The experimental knowledge of the local void-fraction is basic for the derivation of the constitutive equations of two-phase flows. This report deals with measurements of the local void-fraction based on the use of a constant temperature hot-film anemometer associated with a multichannel analyser. After determining the void-fraction profile along a diameter of a vertical pipe (40 mm I.D.), in which air and water flow upwards, we compare the void-fraction averaged over the diameter with the average value measured directly by a {gamma}-ray method. Two runs were made in bubble flow and a third in slug flow. The two methods give results in a good agreement especially for bubble flow. The void-fraction averaged over the cross-section was also calculated from the different profiles and compared in a good manner with the experimental results of R. ROUMY. For bubble flow we verified the theory of S.G. BANKOFF about the shape of the void-fraction profiles. (author) [French] Nous proposons une methode de mesure du taux de vide local a en ecoulement diphasique, basee sur l'emploi d'un anemometre a film chaud a temperature constante dont on etudie la repartition du signal en amplitude dans un analyseur multicanaux. Ayant trace un profil de taux de vide local suivant un diametre d'une conduite verticale de section circulaire parcourue par un ecoulement ascendant d'eau et d'air, nous avons compare la moyenne de {alpha} sur ce diametre a la valeur obtenue par une methode d'absorption de rayons {gamma}. Les essais ont ete faits en ecoulements a bulles et a bouchons. Les deux methodes donnent des resultats concordants en particulier pour les ecoulements a bulles. Le taux de vide moyenne dans la section, calcule a partir des differents profils, a egalement ete compare avec succes aux resultats experimentaux de R. ROUMY. Dans l'etude de la structure radiale des ecoulements a bulles, nous avons verifie l'hypothese de S.G. BAJMKOFF. (auteur)

  6. Measurement of bubble velocity in an air/water flow through a narrow gap by using high-speed cinematography; Ermittlung der Blasengeschwindigkeit einer Luft/Wasser-Spaltstroemung mit Hilfe der Hochgeschwindigkeitskinematographie

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, S.; Friedel, L. [Technische Univ. Hamburg-Harburg, Hamburg (Germany)

    1997-12-01

    To predict the mass flow of a two phase mixture at a given pressure difference through narrow gaps, apart from the change in state of the gas phase during pressure reduction, the knowledge of the fluid dynamics on balance which occurs in the form of a relative velocity between the phases is important. These two influences were examined with the aid of high speed cinematography for a water/air bubble flow. Apart from the quick reduction in pressure due to the sudden reduction in crossection at the entry to the gap, there are no significant differences between the experimentally determined volume change in bubbles of different sizes and that calculated assuming an isothermal change in state. The mean velocity of the bubbles does not differ appreciably from that calculated assuming an homogeneous flow. [Deutsch] Zur Vorhersage des sich bei gegebener Druckdifferenz einstellenden Massenstroms eines Zweiphasengemischs durch enge Spalte ist neben der Zustandsaenderung der Gasphase waehrend der Druckabsenkung u.a. auch die Kenntnis des sich dabei einstellenden fluiddynamischen Ungleichgewichts in Form einer Relativgeschwindigkeit zwischen den Phasen von Bedeutung. Diese beiden Einfluesse wurden mit Hilfe der Hochgeschwindigkeitskinematographie fuer eine Wasser/Luft-Blasenstroemung untersucht. Abgesehen von der raschen Druckabsenkung aufgrund der ploetzlichen Querschnittsverengung im Spalteintritt treten keine nennenswerten Unterschiede zwischen den experimentell ermittelten und den unter der Annahme einer isothermen Zustandsaenderungen berechneten Volumenaenderung verschiedengrosser Blasen auf. Die mittlere Geschwindigkeit der Blasen unterscheidet sich dabei nicht wesentlich von der unter der Annahme einer homogenen Stroemung berechneten. (orig.)

  7. Methylglyoxal at the Air-Water Interface

    Science.gov (United States)

    Wren, S. N.; Gordon, B. P.; McWilliams, L.; Valley, N. A.; Richmond, G.

    2014-12-01

    Recently, it has been suggested that aqueous-phase processing of atmospheric α-dicarbonyl compounds such as methylglyoxal (MG) could constitute an important source of secondary organic aerosol (SOA). The uptake of MG to aqueous particles is higher than expected due to the fact that its carbonyl moieties can hydrate to form diols, as well as the fact that MG can undergo aldol condensation reactions to form larger oligomers in solution. MG is known to be surface active but an improved description of its surface behaviour is crucial to understanding MG-SOA formation, in addition to understanding its gas-to-particle partitioning and cloud forming potential. Here, we employ a combined experimental and theoretical approach involving vibrational sum frequency generation spectroscopy (VSFS), surface tensiometry, molecular dynamics simulations, and density functional theory calculations to study MG's surface adsorption, in both the presence and absence of salts. We are particularly interested in determining MG's hydration state at the surface. Our experimental results indicate that MG slowly adsorbs to the air-water interface and strongly perturbs the water structure there. This perturbation is enhanced in the presence of NaCl. Together our experimental and theoretical results suggest that singly-hydrated MG is the dominant form of MG at the surface.

  8. Flow behaviour and transitions in surfactant-laden gas-liquid vertical flows

    Science.gov (United States)

    Zadrazil, Ivan; Chakraborty, Sourojeet; Matar, Omar; Markides, Christos

    2016-11-01

    The aim of this work is to elucidate the effect of surfactant additives on vertical gas-liquid counter-current pipe flows. Two experimental campaigns were undertaken, one with water and one with a light oil (Exxsol D80) as the liquid phase; in both cases air was used as the gaseous phase. Suitable surfactants were added to the liquid phase up to the critical micelle concentration (CMC); measurements in the absence of additives were also taken, for benchmarking. The experiments were performed in a 32-mm bore and 5-m long vertical pipe, over a range of superficial velocities (liquid: 1 to 7 m/s, gas: 1 to 44 m/s). High-speed axial- and side-view imaging was performed at different lengths along the pipe, together with pressure drop measurements. Flow regime maps were then obtained describing the observed flow behaviour and related phenomena, i.e., downwards/upwards annular flow, flooding, bridging, gas/liquid entrainment, oscillatory film flow, standing waves, climbing films, churn flow and dryout. Comparisons of the air-water and oil-water results will be presented and discussed, along with the role of the surfactants in affecting overall and detailed flow behaviour and transitions; in particular, a possible mechanism underlying the phenomenon of flooding will be presented. EPSRC UK Programme Grant EP/K003976/1.

  9. CFD simulation of transient stage of continuous countercurrent hydrolysis of canola oil

    KAUST Repository

    Wang, Weicheng

    2012-08-01

    Computational Fluid Dynamic (CFD) modeling of a continuous countercurrent hydrolysis process was performed using ANSYS-CFX. The liquid properties and flow behavior such as density, specific heats, dynamic viscosity, thermal conductivity, and thermal expansivity as well as water solubility of the hydrolysis components triglyceride, diglyceride, monoglyceride, free fatty acid, and glycerol were calculated. Chemical kinetics for the hydrolysis reactions were simulated in this model by applying Arrhenius parameters. The simulation was based on actual experimental reaction conditions including temperature and water-to-oil ratio. The results not only have good agreement with experimental data but also show instantaneous distributions of concentrations of every component in hydrolysis reaction. This model provided visible insight into the continuous countercurrent hydrolysis process. © 2012 Elsevier Ltd.

  10. Hydrodynamics of a fixed camphor boat at the air-water interface

    Science.gov (United States)

    Singh, Dhiraj; Akella, Sathish; Singh, Ravi; Mandre, Shreyas; Bandi, Mahesh

    2015-11-01

    A camphor tablet, when introduced at the air-water interface undergoes sublimation and the camphor vapour spreads radially outwards across the surface. This radial spreading of camphor is due to Marangoni forces setup by the camphor concentration gradient. We report experiments on the hydrodynamics of this process for a camphor tablet held fixed at the air-water interface. During the initial transient, the time-dependent spread radius R (t) of camphor scales algebraically with time t (R (t) ~t 1 / 2) in agreement with empirical scalings reported for spreading of volatile oils on water surface. But unlike surfactants, the camphor stops spreading when the influx of camphor from the tablet onto the air-water interface is balanced by the outflux of camphor due to evaporation, and a steady-state condition is reached. The spreading camphor however, shears the underlying fluid and sets up bulk convective flow. We explain the coupled steady-state dynamics between the interfacial camphor spreading and bulk convective flow with a boundary layer approximation, supported by experimental evidence. This work was supported by the Collective Interactions Unit, OIST Graduate University.

  11. Multifraction separation in countercurrent chromatography (MCSGP).

    Science.gov (United States)

    Krättli, Martin; Müller-Späth, Thomas; Morbidelli, Massimo

    2013-09-01

    The multicolumn countercurrent solvent gradient purification (MCSGP) process is a continuous countercurrent multicolumn chromatography process capable of performing three fraction separations while applying a linear gradient of some modifier. This process can then be used either for the purification of a single species from a multicomponent mixture or to separate a three component mixture in one single operation. In this work, this process is extended to the separation of multifractions, in principle with no limitation. To achieve this goal the MCSGP standard process is extended by introducing one extra separation section per extra fraction to be isolated. Such an extra separation section is realized in this work through a single additional column, so that a n fraction MCSGP process can be realized using a minimum of n columns. Two separation processes were considered to experimentally demonstrate the possibility of realizing a four-fraction MCSGP unit able to purify two intermediate products in a given multicomponent mixture. The first one was a model mixture containing four different proteins. The two proteins eluting in the center of the chromatogram were purified with yields equal to 95% for the early eluting and 92% for the later eluting one. The corresponding purities were 94% and 97%, respectively. Such performance was well superior to that of the batch operation with the same modifier gradient which for the same purity values could not achieve yields larger than 67% and 81%, respectively. Similar performance improvements were found for the second separation where two out of seven charge variants which constitute the mAb Cetuximab currently available on the market have been purified in one single operation using a four-fraction MCSGP unit. In this case, yields of 81% and 65% were obtained with purities of 90% and 89%, respectively. These data compare well with the corresponding data from batch chromatography where with the same gradient and for the same

  12. Robust design of binary countercurrent adsorption separation processes

    Energy Technology Data Exchange (ETDEWEB)

    Storti, G. (Univ. degli Studi di Padova (Italy)); Mazzotti, M.; Morbidelli, M.; Carra, S. (Piazza Leonardo da Vinci, Milano (Italy))

    1993-03-01

    The separation of a binary mixture, using a third component having intermediate adsorptivity as desorbent, in a four section countercurrent adsorption separation unit is considered. A procedure for the optimal and robust design of the unit is developed in the frame of Equilibrium Theory, using a model where the adsorption equilibria are described through the constant selectivity stoichiometric model, while mass-transfer resistances and axial mixing are neglected. By requiring that the unit achieves complete separation, it is possible to identify a set of implicity constraints on the operating parameters, that is, the flow rate ratios in the four sections of the unit. From these constraints explicit bounds on the operating parameters are obtained, thus yielding a region in the operating parameters space, which can be drawn a priori in terms of the adsorption equilibrium constants and the feed composition. This result provides a very convenient tool to determine both optimal and robust operating conditions. The latter issue is addressed by first analyzing the various possible sources of disturbances, as well as their effect on the separation performance. Next, the criteria for the robust design of the unit are discussed. Finally, these theoretical findings are compared with a set of experimental results obtained in a six port simulated moving bed adsorption separation unit operated in the vapor phase.

  13. Modelling counter-current chromatography: a chemical engineering perspective.

    Science.gov (United States)

    Kostanian, A E

    2002-10-11

    In conventional chromatography, a solute is usually viewed to be longitudinally transported only in the mobile phase, remaining longitudinally motionless in the stationary phase. In counter-current chromatography, both phases undergo intense mixing in the variable force field of a coil planet centrifuge and longitudinal dispersion of matter in the stationary phase is not to be excluded. To take into account longitudinal mixing in both phases, a cell model of chromatographic process is proposed in which the number of perfectly mixed cells n is determined by the rates of mixing in stationary (Ds) and mobile (Dm) phases by the equation n = LF/(2ADc)/(1 + Sf(lambda - 1)) with A = K(D)D(S)/Dm (F, L, Ac and KD are the mobile phase flow-rate, column length, column cross-section and distribution ratio, respectively). This equation has been derived by comparing the discontinuous cell model with continuous diffusion assuming equilibrium conditions. Parameter determination and their relationships are discussed.

  14. Shear turbulence, Langmuir circulation and scalar transfer at an air-water interface

    Science.gov (United States)

    Hafsi, Amine; Tejada-Martinez, Andres; Veron, Fabrice

    2016-11-01

    DNS of an initially quiescent coupled air-water interface driven by an air-flow with free stream speed of 5 m/s generates gravity-capillary waves and small-scale (centimeter-scale) Langmuir circulation (LC) beneath the interface. In addition to LC, the waterside turbulence is characterized by shear turbulence with structures similar to classical "wall streaks" in wall-bounded flow. These streaks, denoted here as "shear streaks", consist of downwind-elongated vortices alternating in sign in the crosswind direction. The presence of interfacial waves causes interaction between these vortices giving rise to bigger vortices, namely LC. LES with momentum equation augmented with the Craik-Leibovich (C-L) vortex force is used to understand the roles of the shear streaks (i.e. the shear turbulence) and the LC in determining scalar flux from the airside to the waterside and vertical scalar transport beneath. The C-L force consists of the cross product between the Stokes drift velocity (induced by the interface waves) and the flow vorticity. It is observed that Stokes drift shear intensifies the shear streaks (with respect to flow without wave effects) leading to enhanced scalar flux at the air-water interface. LC leads to increased vertical scalar transport at depths below the interface.

  15. Thermal hydrodynamic analysis of a countercurrent gas centrifuge; Analise termo hidrodinamica de uma centrifuga a contracorrente

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Delvonei Alves de

    1999-07-01

    The influence of the thermal countercurrent on the separative performance of countercurrent centrifuges is treated in this work. The methodology used consists in modeling the gas flow inside the rotor under thermal boundary conditions supplied by the structural thermal model. The gas flow model, also called hydrodynamical model, is based on the Finite Volume Method for cylindrical geometry with azimuthal symmetry. The structural thermal model is based on the Nodal Method and take into account simultaneously, the conduction convection and radiation phenomena. The procedure adopted for this study consisted in the definition of the operational and geometric conditions of a centrifuge which was used as a pattern to the accomplished analysis. This configuration, called 'Standard Centrifuge', was used for the accomplishment of several simulations where the importance of the realistic boundary thermal conditions for the numerical evaluation of the centrifuge separative capacity was evidenced. A selective alteration for the optical properties based on simple engineering procedures was proposed. An improvement of 5% was obtained with this alteration. (author)

  16. Flume experiments on wind induced flow in static water bodies in the presence of protruding vegetation

    Science.gov (United States)

    Banerjee, Tirtha; Muste, Marian; Katul, Gabriel

    2015-02-01

    The problem of wind-induced flow in inland waters is drawing significant research attention given its relevance to a plethora of applications in wetlands including treatment designs, pollution reduction, and biogeochemical cycling. The present work addresses the role of wind induced turbulence and waves within an otherwise static water body in the presence of rigid and flexible emergent vegetation through flume experimentation and time series analysis. Because no prior example of Particle Imaging Velocimetry (PIV) experiments involving air-water and flexible oscillating components have been found in the literature, a spectral analysis framework is needed and proposed here to guide the analysis involving noise, wave and turbulence separation. The experiments reveal that wave and turbulence effects are simultaneously produced at the air-water interface and the nature of their coexistence is found to vary with different flow parameters including water level, mean wind speed, vegetation density and its flexibility. For deep water levels, signature of fine-scaled inertial turbulence is found at deeper layers of the water system. The wave action appears stronger close to the air-water interface and damped by the turbulence deeper inside the water system. As expected, wave action is found to be dominated in a certain frequency range driven by the wind forcing, while it is also diffused to lower frequencies by means of (wind-induced) oscillations in vegetation. Regarding the mean water velocity, existence of a counter-current flow and its switching to fully forward flow in the direction of the wind under certain combinations of flow parameters were studied. The relative importance of wave and turbulence to the overall energy, degree of anisotropy in the turbulent energy components, and turbulent momentum transport at different depths from the air-water interface and flow combinations were then quantified. The flume experiments reported here differ from previous laboratory

  17. Pleistocene dynamics of the Pacific South Equatorial Countercurrent

    Science.gov (United States)

    Nuernberg, D.; Raddatz, J.; Rippert, N.; Tiedemann, R.

    2014-12-01

    The Western Pacific Warm Pool (WPWP) with extremely high sea-surface-temperatures (SST) is a key area for global climate. It also acts as a crossroad for mode and intermediate water masses such as the South Equatorial Countercurrent (SECC) transporting water masses originating from higher latitudes. The SECC flows above the main thermocline and strongly interacts with the Intertropical Convergence Zone (ITCZ) and South Pacific Convergence Zone (SPCZ). To constrain changes in sea-surface and subsurface water mass dynamics affecting thermocline depth, we reconstruct SST, subSST and salinity conditions using combined δ18O and Mg/Ca signals of surface (Globigerinoides ruber, Globigerinoides sacculifer) and subsurface dwelling (Globorotalia tumida) planktonic foraminifera. Our study is based on RV SONNE SO-225 piston cores retrieved from Manihiki plateau, which is located at the southeastern margin of the WPWP (between ~ 5°S-15°S and 170-160°W). The proxy records cover the last ~ 3 Myr SSTMg/Ca remained nearly constant throughout the entire Pleistocene varying between ~30 to 32 (°C), while the subSSTMg/Ca reconstructions reveal pronounced variations from ~10 to 16 (°C). Our results imply that the WPWP thermocline depth has undergone significant vertical movements throughout the Pleistocene. Notably, thermocline depth is continuously decreasing from the early to the late Pleistocene, and coincides with the change from the 41 kyr to a dominant 100 kyr climate periodicity between 1 and 1.7 Ma. We hypothesize that the repeated change in thermocline depth is due to either 1) changes in mode or intermediate water masses advection from Southern Ocean sources via "ocean tunneling", 2) changes in the tropical Pacific wind regime, and/or 3) changes in the Western Pacific Monsoon sytem.

  18. Counter-current thermocapillary migration of bubbles in self-rewetting liquids

    Science.gov (United States)

    Nazareth, R.; Saenz, P.; Sefiane, K.; Kim, J.; Valluri, P.

    2016-11-01

    In this work, we study the counter-current thermocapillary propulsion of a suspended bubble in the fluid flowing inside a channel subject to an axial temperature gradient when the surface tension dependence on temperature is non-monotonic. We use direct numerical simulations to address the two-phase conservation of mass, momentum and energy with a volume-of-fluid method to resolve the deformable interface. Two distinct regimes of counter-current bubble migration are characterized: i) "exponential decay" where the bubble decelerates rapidly until it comes to a halt at the spatial position corresponding to the minimum surface tension and ii) "sustained oscillations" where the bubble oscillates about the point of minimum surface tension. We illustrate how these sustained oscillations arise at low capillary number O(10-5) and moderate Reynolds number O(10) and, they are dampened by viscosity at lower Reynolds number. These results are in agreement with the experiments by Shanahan and Sefiane (Sci. Rep. 4, 2014). The work was supported by the Science without Borders program from CAPES agency of Brazilian Ministry of Education and the European Commission's Thermapower Project (294905).

  19. Automation System in Rare Earths Countercurrent Extraction Processes

    Institute of Scientific and Technical Information of China (English)

    贾江涛; 严纯华; 廖春生; 吴声; 王明文; 李标国

    2001-01-01

    Based on the countercurrent extraction theory for optimized designing and simulating, the rare earth separation processes, the selection of the detecting points (stages) and on-line analysis for elements, the simulation of open loop response and its response speed, the diagnosis and the regulative prescription for running the solvent extraction cascades were studied.

  20. Mixer-settler counter-current chromatography with multiple spiral disk assembly.

    Science.gov (United States)

    Ito, Yoichiro; Clary, Robert; Sharpnak, Frank; Metger, Howard; Powell, Jimmie

    2007-11-23

    A novel system for performing high-speed counter-current chromatography has been developed for separation of biopolymers using polymer phase systems. The spiral disk assembly consisting of eight units, each equipped with over 300 mixer-settler sets, was constructed and performance evaluated in terms of retention of the stationary phase and separation efficiency. A series of experiments was performed with a polymer phase system composed of polyethylene glycol 1000 (12.5%, w/w) and dibasic potassium phosphate (12.5%, w/w) using two stable protein samples of myoglobin and lysozyme at various experimental conditions of flow rates and revolution speeds. The best results were obtained with revolution speeds of 800-1000rpm at flow rates of 0.25-0.5ml/min where the partition efficiency of several 100 theoretical plates was achieved with over 50% stationary phase retention.

  1. Separation and purification of four compounds from Desmodium styracifolium using off-line two-dimensional high-speed counter-current chromatography.

    Science.gov (United States)

    Su, Wen; Liu, Qi; Yang, Qing; Yu, Jingang; Chen, Xiaoqing

    2013-10-01

    An off-line 2D high-speed counter-current chromatography technique in preparative scale has been successfully applied to separate and purify the main compounds from the ethyl acetate extract of Desmodium styracifolium. A two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water at an optimized volume ratio of 1:2:1:2 v/v/v/v was used. Conventional high-speed counter-current chromatography was used as the first dimension, and the upper phase of the solvent system was used as the stationary phase in the head-to-tail elution mode at a flow rate of 2.0 mL/min and a rotation speed of 900 rpm. Recycling high-speed counter-current chromatography served as the second dimension to separate an impure fraction of the first dimension. A total of four well-separated substances including vanillic acid (1), β-sitosterol (2), formononetin (3), and aromadendrin (4) were obtained, and their purities and structures were identified by HPLC-MS and (1) H NMR spectroscopy. The results illustrated that off-line 2D high-speed counter-current chromatography is an effective way to isolate compounds in complex samples.

  2. Carbon-foam finned tubes in air-water heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Yu Qijun [Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, N6A 5B8 (Canada)]. E-mail: qyu4@eng.uwo.ca; Straatman, Anthony G. [Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, N6A 5B8 (Canada)]. E-mail: astraatman@eng.uwo.ca; Thompson, Brian E. [Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada)]. E-mail: thompson@eng.uottawa.ca

    2006-02-01

    An engineering model is formulated to account for the effects of porosity and pore diameter on the hydrodynamic and thermal performance of a carbon-foam finned tube heat exchanger. The hydrodynamic and thermal resistances are obtained from well-established correlations that are extended herein to account for the influence of the porous carbon foam. The influence of the foam is characterized on the basis of a unit-cube geometric model that describes the internal structure, the exposed surface, the permeability and the effective conductivity as a function of porosity and pore diameter. The engineering model is validated by comparison with experiments that characterize heat transfer in an air-water radiator made from porous carbon foam. The model is also used in to conduct a parametric study to show the influence of the porosity and pore diameter of the foam. The parametric study suggests that in comparison to conventional aluminum finned-tube radiators, improvements of approximately 15% in thermal performance are possible without changing the frontal area, or the air flow rate and pressure drop. The engineering model developed herein can be used by engineers to assess quantitatively the suitability of porous carbon foam as a fin material in the design of air-water heat exchangers.

  3. Carbon-foam finned tubes in air-water heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qijun; Straatman, Anthony G. [Department of Mechanical and Materials Engineering, The University of Western Ontario, London, ON (Canada); Thompson, Brian E. [Department of Mechanical Engineering, The University of Ottawa, Ottawa, ON (Canada)

    2006-02-01

    An engineering model is formulated to account for the effects of porosity and pore diameter on the hydrodynamic and thermal performance of a carbon-foam finned tube heat exchanger. The hydrodynamic and thermal resistances are obtained from well-established correlations that are extended herein to account for the influence of the porous carbon foam. The influence of the foam is characterized on the basis of a unit-cube geometric model that describes the internal structure, the exposed surface, the permeability and the effective conductivity as a function of porosity and pore diameter. The engineering model is validated by comparison with experiments that characterize heat transfer in an air-water radiator made from porous carbon foam. The model is also used in to conduct a parametric study to show the influence of the porosity and pore diameter of the foam. The parametric study suggests that in comparison to conventional aluminum finned-tube radiators, improvements of approximately 15% in thermal performance are possible without changing the frontal area, or the air flow rate and pressure drop. The engineering model developed herein can be used by engineers to assess quantitatively the suitability of porous carbon foam as a fin material in the design of air-water heat exchangers. (author)

  4. Mass transfer in thin films under counter-current gas: experiments and numerical study

    Science.gov (United States)

    Lucquiaud, Mathieu; Lavalle, Gianluca; Schmidt, Patrick; Ausner, Ilja; Wehrli, Marc; O Naraigh, Lennon; Valluri, Prashant

    2016-11-01

    Mass transfer in liquid-gas stratified flows is strongly affected by the waviness of the interface. For reactive flows, the chemical reactions occurring at the liquid-gas interface also influence the mass transfer rate. This is encountered in several technological applications, such as absorption units for carbon capture. We investigate the absorption rate of carbon dioxide in a liquid solution. The experimental set-up consists of a vertical channel where a falling film is sheared by a counter-current gas flow. We measure the absorption occurring at different flow conditions, by changing the liquid solution, the liquid flow rate and the gas composition. With the aim to support the experimental results with numerical simulations, we implement in our level-set flow solver a novel module for mass transfer taking into account a variant of the ghost-fluid formalism. We firstly validate the pure mass transfer case with and without hydrodynamics by comparing the species concentration in the bulk flow to the analytical solution. In a final stage, we analyse the absorption rate in reactive flows, and try to reproduce the experimental results by means of numerical simulations to explore the active role of the waves at the interface.

  5. The eastward subtropical countercurrent on isopycnal surface in the western North Pacific

    Institute of Scientific and Technical Information of China (English)

    LI; Rongfeng; YOU; Xiaobao; Peter; C.; Chu

    2005-01-01

    The monthly circulations on isopycnal surface in the western North Pacific are calculated based on the Navy's Generalized Digital Environmental Model climatological temperature and salinity data on a 1/2°× 1/2° grid using a P-vector method. The eastward Subtropical Countercurrent (STCC) in the central subtropical gyre has been studied with emphasis on its spatial distribution, vertical structure, volume transport and its nearby eddy phenomenon. The results reproduce the observed feature of STCC, and reveal some new phenomena on isopycnal surface, such as: (1) Atσθ= 24.6, there is strong seasonal variability in the distribution, origin and flow status of STCC. There is no STCC in January, February and March. (2) From May to October, a branch of the Kuroshio Countercurrent to the south of Japan merges into STCC, which increases the velocity of STCC and widens its width. (3) The velocity vector field shows that STCC and nearby eddies coexist. (4) The eastward volume transport of STCC across 137.5°E is the strongest in summer with the maximum of 6.9 Sv ( 1 Sv ≡ 106 m3 s-1) in August, and weaker in spring and autumn with 1.7 Sv in April and 1.6 Sv in November. Most of the transports of STCC occur between isopycnal surfaces 24.0σθand 25.0σθ. (5) The distributions of the zonal flow along 137.5°E show that the flow core of STCC is between 24.3σθand 24.7σθ.

  6. Air/water oxydesulfurization of coal: laboratory investigation

    Energy Technology Data Exchange (ETDEWEB)

    Warzinski, R. P.; Friedman, S.; Ruether, J. A.; LaCount, R. B.

    1980-08-01

    Air/water oxidative desulfurization has been demonstrated in autoclave experiments at the Pittsburgh Energy Technology Center for various coals representative of the major US coal basins. This experimentation has shown that the reaction proceeds effectively for pulverized coals at temperatures of 150 to 200/sup 0/C with air at a total system pressure of 500 to 1500 psig. Above 200/sup 0/C, the loss of coal and product heating value increases due to oxidative consumption of carbon and hydrogen. The pyritic sulfur solubilization reactions are typically complete (95 percent removal) within 15 to 40 minutes at temperature; however, significant apparent organic sulfur removal requires residence times of up to 60 minutes at the higher temperatures. The principal products of the reaction are sulfuric acid, which can be neutralized with limestone, and iron oxide. Under certain conditions, especially for high pyritic sulfur coals, the precipitation of sulfur-containing compounds from the products of the pyrite reaction may cause anomalous variations in the sulfur form data. The influence of various parameters on the efficiency of sulfur removal from coal by air/water oxydesulfurization has been studied.

  7. Polydopamine Films from the Forgotten Air/Water Interface.

    Science.gov (United States)

    Ponzio, Florian; Payamyar, Payam; Schneider, Anne; Winterhalter, Mathias; Bour, Jérôme; Addiego, Frédéric; Krafft, Marie-Pierre; Hemmerle, Joseph; Ball, Vincent

    2014-10-02

    The formation of polydopamine under mild oxidation conditions from dopamine solutions with mechanical agitation leads to the formation of films that can functionalize all kinds of materials. In the absence of stirring of the solution, we report the formation of polydopamine films at the air/water interface (PDA A/W) and suggest that it arises from an homogeneous nucleation process. These films grow two times faster than in solution and can be deposited on hydrophilic or hydrophobic substrates by the Langmuir-Schaeffer technique. Thanks to this new method, porous and hydrophobic materials like polytetrafluoroethylene (PTFE) membranes can be completely covered with a 35 nm thick PDA A/W film after only 3h of reaction. Finally the oxidation of a monomer followed by a polymerization in water is not exclusive to polydopamine since we also transferred polyaniline functional films from the air/water interface to solid substrates. These findings suggest that self-assembly from a solution containing hydrophilic monomers undergoing a chemical transformation (here oxidation and oligomerization) could be a general method to produce films at the liquid/air interface.

  8. Counter-current membrane reactor for WGS process: Membrane design

    Energy Technology Data Exchange (ETDEWEB)

    Piemonte, Vincenzo; Favetta, Barbara [Department of Chemical Engineering Materials and Environment, University of Rome ' ' La Sapienza' ' , via Eudossiana 18, 00184 Rome (Italy); De Falco, Marcello [Faculty of Engineering, University Campus Bio-Medico of Rome, via Alvaro del Portillo 21, 00128 Rome (Italy); Basile, Angelo [CNR-ITM, c/o University of Calabria, Via Pietro Bucci, Cubo 17/C, 87030 Rende (CS) (Italy)

    2010-11-15

    Water gas shift (WGS) is a thermodynamically limited reaction which has to operate at low temperatures, reducing kinetics rate and increasing the amount of catalyst required to reach valuable CO conversions. It has been widely demonstrated that the integration of hydrogen selective membranes is a promising way to enhance WGS reactors performance: a Pd-based MR operated successfully overcoming the thermodynamic constraints of a traditional reactor thanks to the removal of hydrogen from reaction environment. In the first part of a MR, the H{sub 2} partial pressure starts from a minimum value since the reaction has not started. As a consequence, if the carrier gas in the permeation zone is sent in counter-current, which is the most efficient configuration, in the first reactor section the H{sub 2} partial pressure in reaction zone is low while in the permeation zone is high, potentially implying back permeation. This means a bad utilization of the first part of the membrane area and thus, a worsening of the MR performance with lower H{sub 2} recovery and lower CO conversion with respect to the case in which the whole selective surface is properly used. To avoid this problem different MR configurations were evaluated by a 1-D pseudo-homogeneous model, validated with WGS industrial data reported in scientific literature. It was demonstrated that the permeated H{sub 2} flow rate per membrane surface, i.e. the membrane flux, strongly improves if selective membrane is placed only in the second part of the reactor: in fact, if the membrane is placed at L{sub m}/L{sub tot} = 0.5, the membrane flux is 0.2 kmol/(m{sup 2}h) about, if it is placed along all reactor tube (L{sub m}/L{sub tot} = 1), flux is 0.05 kmol/(m{sup 2}h). The effect of the L/D reactor ratio and of the reactor wall temperature on the CO conversion were also assessed. (author)

  9. Countercurrent Process for Lignin Separation from Biomass Matrix

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Kadam; Ed Lehrburger

    2006-03-31

    The overall goal of the project was to test the concept of using a twin-screw extruder to conduct autohydrolysis pretreatment of wheat straw in countercurrent fashion, demonstrate in situ solid/liquid separation, and produce a low-lignin cellulose product using ethanol as an extractant. The resultant solid product is suitable for sugar production through enzymatic hydrolysis and for pulp applications. Pilot-scale equipment was used to successfully demonstrate the process both for sugar and pulp applications.

  10. Powder wettability at a static air-water interface.

    Science.gov (United States)

    Dupas, Julien; Forny, Laurent; Ramaioli, Marco

    2015-06-15

    The reconstitution of a beverage from a dehydrated powder involves several physical mechanisms that determine the practical difficulty to obtain a homogeneous drink in a convenient way and within an acceptable time for the preparation of a beverage. When pouring powder onto static water, the first hurdle to overcome is the air-water interface. We propose a model to predict the percentage of powder crossing the interface in 45 s, namely the duration relevant for this application. We highlight theoretically the determinant role of the contact angle and of the particle size distribution. We validate experimentally the model for single spheres and use it to predict the wettability performance of commercial food powders for different contact angles and particles sizes. A good agreement is obtained when comparing the predictions and the wettability of the tested powders.

  11. Reacting chemistry at the air-water interface

    Science.gov (United States)

    Murakami, Tomoyuki; Morgan, Thomas; Huwel, Lutz; Graham, William

    2016-09-01

    Plasma interaction with gas-liquid interfaces is becoming increasingly important in biological applications, chemical analysis and medicine. It introduces electrons, new ionic species and reactive species and contributes to chemical and electrical self-organization at the interface. To provide insight into the associated physics and chemistry at work in the evolution of the plasma in the air-water interface (AWI), a time-dependent one-dimensional modelling has been developed. The numerical simulation is used to solve the kinetic equations and help identify the important reaction mechanisms and describe the phenomena associated with hundreds of reacting pathways in gas-phase and liquid-phase AWI chemistry. This work was partly supported by JSPS KAKENHI Grant Number 16K04998.

  12. Wind driven vertical transport in a vegetated, wetland water column with air-water gas exchange

    Science.gov (United States)

    Poindexter, C.; Variano, E. A.

    2010-12-01

    Flow around arrays of cylinders at low and intermediate Reynolds numbers has been studied numerically, analytically and experimentally. Early results demonstrated that at flow around randomly oriented cylinders exhibits reduced turbulent length scales and reduced diffusivity when compared to similarly forced, unimpeded flows (Nepf 1999). While horizontal dispersion in flows through cylinder arrays has received considerable research attention, the case of vertical dispersion of reactive constituents has not. This case is relevant to the vertical transfer of dissolved gases in wetlands with emergent vegetation. We present results showing that the presence of vegetation can significantly enhance vertical transport, including gas transfer across the air-water interface. Specifically, we study a wind-sheared air-water interface in which randomly arrayed cylinders represent emergent vegetation. Wind is one of several processes that may govern physical dispersion of dissolved gases in wetlands. Wind represents the dominant force for gas transfer across the air-water interface in the ocean. Empirical relationships between wind and the gas transfer coefficient, k, have been used to estimate spatial variability of CO2 exchange across the worlds’ oceans. Because wetlands with emergent vegetation are different from oceans, different model of wind effects is needed. We investigated the vertical transport of dissolved oxygen in a scaled wetland model built inside a laboratory tank equipped with an open-ended wind tunnel. Plastic tubing immersed in water to a depth of approximately 40 cm represented emergent vegetation of cylindrical form such as hard-stem bulrush (Schoenoplectus acutus). After partially removing the oxygen from the tank water via reaction with sodium sulfite, we used an optical probe to measure dissolved oxygen at mid-depth as the tank water re-equilibrated with the air above. We used dissolved oxygen time-series for a range of mean wind speeds to estimate the

  13. Simulating Urban Tree Effects on Air, Water, and Heat Pollution Mitigation: iTree-Hydro Model

    Science.gov (United States)

    Yang, Y.; Endreny, T. A.; Nowak, D.

    2011-12-01

    Urban and suburban development changes land surface thermal, radiative, porous, and roughness properties and pollutant loading rates, with the combined effect leading to increased air, water, and heat pollution (e.g., urban heat islands). In this research we present the USDA Forest Service urban forest ecosystem and hydrology model, iTree Eco and Hydro, used to analyze how tree cover can deliver valuable ecosystem services to mitigate air, water, and heat pollution. Air pollution mitigation is simulated by dry deposition processes based on detected pollutant levels for CO, NO2, SO2, O3 and atmospheric stability and leaf area indices. Water quality mitigation is simulated with event mean concentration loading algorithms for N, P, metals, and TSS, and by green infrastructure pollutant filtering algorithms that consider flow path dispersal areas. Urban cooling considers direct shading and indirect evapotranspiration. Spatially distributed estimates of hourly tree evapotranspiration during the growing season are used to estimate human thermal comfort. Two main factors regulating evapotranspiration are soil moisture and canopy radiation. Spatial variation of soil moisture is represented by a modified urban topographic index and radiation for each tree is modified by considering aspect, slope and shade from surrounding buildings or hills. We compare the urban cooling algorithms used in iTree-Hydro with the urban canopy and land surface physics schemes used in the Weather Research and Forecasting model. We conclude by identifying biophysical feedbacks between tree-modulated air and water quality environmental services and how these may respond to urban heating and cooling. Improvements to this iTree model are intended to assist managers identify valuable tree services for urban living.

  14. Situation and Developing Trend of Rare-Earth Countercurrent Extraction Processes Control

    Institute of Scientific and Technical Information of China (English)

    柴天佑; 杨辉

    2004-01-01

    On the basis of the description of the rare-earth countercurrent extraction process, the on-line detecting method and equipments of rare-earth elements and the application in the process of the rare-earth countercurrent extraction are summarized. The procedure simulation of the computer, the automation control method and its current application are also mentioned in the process of rare-earth countercurrent extraction. The method of soft sensor is proposed. Optimal control method based on object-oriented rare-earth countercurrent extraction process and integrated automation system composed of process management system and process control system are presented, which are the developing direction of the automation of rare-earth countercurrent extraction process.

  15. Micrometeorological Measurement of Fetch- and Atmospheric Stability-Dependent Air- Water Exchange of Legacy Semivolatile Organic Contaminants in Lake Superior

    Science.gov (United States)

    Perlinger, J. A.; Tobias, D. E.; Rowe, M. D.

    2008-12-01

    Coastal waters including the Laurentian Great Lakes are particularly susceptible to local, regional, and long- range transport and deposition of semivolatile organic contaminants (SOCs) as gases and/or associated with particles. Recently-marketed SOCs can be expected to undergo net deposition in surface waters, whereas legacy SOCs such as polychlorinated biphenyls (PCBs) are likely to be at equilibrium with respect to air-water exchange, or, if atmospheric concentrations decrease through, e.g., policy implementation, to undergo net gas emission. SOC air-water exchange flux is usually estimated using the two-film model. This model describes molecular diffusion through the air and water films adjacent to the air-water interface. Air-water exchange flux is estimated as the product of SOC fugacity, typically based on on-shore gaseous concentration measurements, and a transfer coefficient, the latter which is estimated from SOC properties and environmental conditions. The transfer coefficient formulation commonly applied neglects resistance to exchange in the internal boundary layer under atmospherically stable conditions, and the use of on-shore gaseous concentration neglects fetch-dependent equilibration, both of which will tend to cause overestimation of flux magnitude. Thus, for legacy chemicals or in any highly contaminated surface water, the rate at which the water is cleansed through gas emission tends to be over-predicted using this approach. Micrometeorological measurement of air-water exchange rates of legacy SOCs was carried out on ships during four transect experiments during off-shore flow in Lake Superior using novel multicapillary collection devices and thermal extraction technology to measure parts-per-quadrillion SOC levels. Employing sensible heat in the modified Bowen ratio, fluxes at three over-water stations along the transects were measured, along with up-wind, onshore gaseous concentration and aqueous concentration. The atmosphere was unstable for

  16. 14 CFR 1274.926 - Clean Air-Water Pollution Control Acts.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Clean Air-Water Pollution Control Acts...-Water Pollution Control Acts. Clean Air-Water Pollution Control Acts July 2002 If this cooperative... 91-604) and section 308 of the Federal Water Pollution Control Act, as amended (33 U.S.C. 1251 et...

  17. Structure and dynamics of egg white ovalbumin adsorbed at the air/water interface

    NARCIS (Netherlands)

    Kudryashova, E.V.; Meinders, M.B.J.; Visser, A.J.W.G.; Hoek, A. van; Jongh, H.H.J. de

    2003-01-01

    The molecular properties of egg white ovalbumin adsorbed at the air/water interface were studied using infrared reflection absorption spectroscopy (IRRAS) and time-resolved fluorescence anisotropy (TRFA) techniques. Ovalbumin adsorbed at the air/ water interface adopts a characteristic partially unf

  18. The Effect of Rain on Air-Water Gas Exchange

    Science.gov (United States)

    Ho, David T.; Bliven, Larry F.; Wanninkhof, Rik; Schlosser, Peter

    1997-01-01

    The relationship between gas transfer velocity and rain rate was investigated at NASA's Rain-Sea Interaction Facility (RSIF) using several SF, evasion experiments. During each experiment, a water tank below the rain simulator was supersaturated with SF6, a synthetic gas, and the gas transfer velocities were calculated from the measured decrease in SF6 concentration with time. The results from experiments with IS different rain rates (7 to 10 mm/h) and 1 of 2 drop sizes (2.8 or 4.2 mm diameter) confirm a significant and systematic enhancement of air-water gas exchange by rainfall. The gas transfer velocities derived from our experiment were related to the kinetic energy flux calculated from the rain rate and drop size. The relationship obtained for mono-dropsize rain at the RSIF was extrapolated to natural rain using the kinetic energy flux of natural rain calculated from the Marshall-Palmer raindrop size distribution. Results of laboratory experiments at RSIF were compared to field observations made during a tropical rainstorm in Miami, Florida and show good agreement between laboratory and field data.

  19. Nonlinear Acoustics at the Air-Water Free Surface

    Science.gov (United States)

    Pree, Seth; Naranjo, Brian; Putterman, Seth

    2016-11-01

    According to linear acoustics, airborne sound incident on a water surface transmits only a tenth of a percent of its energy. This difficulty of transmitting energy across the water surface limits the feasibility of standoff ultrasound imaging. We propose to overcome this long standing problem by developing new methods of coupling into the medium at standoff. In particular, we believe that the acoustic nonlinearity of both the air and the medium may yield a range of effects in the vicinity of the surface permitting an efficient transmission of ultrasound from the air into the medium. The recent commercial availability of parametric speakers that deliver modulated 100kHz ultrasound at 135dB to nonlinearly generate music at 95dB provides an interesting platform with which to revisit the transmission of sound across acoustic impedance mismatches. We show results of experimental studies of the behavior of the air-water free surface when subjected to large amplitude acoustic pressures from the air. This work was supported by the ARO STIR program.

  20. Mathematical model of the dynamics of countercurrent chromatography

    Institute of Scientific and Technical Information of China (English)

    陆向红; 任其龙; 吴平东

    2002-01-01

    A mathematical model of the dynamic behavior of countercurrent chromatography was proposed, and the model parameters, including the partition coefficient, the axial dispersion coefficient, the intraparticle diffusion coefficient and the external mass ransfer coefficient were calculated by the method of chromatogram moment analysis. Comparison of the experimental chromatograms of caffeine and theophylline determined in this work with the simulated curves computed by the proposed model showed fairly good agreement. Further, the difference between the average identified the partition coefficients by chromatogram moment analysis and the experimental values was small also, and the relationship between the external mass transfer rate and the linear velocity was similar to that obtained with solid-liquid chromatography.

  1. Proton Transfers at the Air-Water Interface

    Science.gov (United States)

    Mishra, Himanshu

    Proton transfer reactions at the interface of water with hydrophobic media, such as air or lipids, are ubiquitous on our planet. These reactions orchestrate a host of vital phenomena in the environment including, for example, acidification of clouds, enzymatic catalysis, chemistries of aerosol and atmospheric gases, and bioenergetic transduction. Despite their importance, however, quantitative details underlying these interactions have remained unclear. Deeper insight into these interfacial reactions is also required in addressing challenges in green chemistry, improved water quality, self-assembly of materials, the next generation of micro-nanofluidics, adhesives, coatings, catalysts, and electrodes. This thesis describes experimental and theoretical investigation of proton transfer reactions at the air-water interface as a function of hydration gradients, electrochemical potential, and electrostatics. Since emerging insights hold at the lipid-water interface as well, this work is also expected to aid understanding of complex biological phenomena associated with proton migration across membranes. Based on our current understanding, it is known that the physicochemical properties of the gas-phase water are drastically different from those of bulk water. For example, the gas-phase hydronium ion, H3O +(g), can protonate most (non-alkane) organic species, whereas H 3O+(aq) can neutralize only relatively strong bases. Thus, to be able to understand and engineer water-hydrophobe interfaces, it is imperative to investigate this fluctuating region of molecular thickness wherein the 'function' of chemical species transitions from one phase to another via steep gradients in hydration, dielectric constant, and density. Aqueous interfaces are difficult to approach by current experimental techniques because designing experiments to specifically sample interfacial layers (quantum mechanics and molecular dynamics to simulate our experiments toward gaining insight at the

  2. Air-water oxygen exchange in a large whitewater river

    Science.gov (United States)

    Hall, Robert O.; Kennedy, Theodore A.; Rosi-Marshall, Emma J.

    2012-01-01

    Air-water gas exchange governs fluxes of gas into and out of aquatic ecosystems. Knowing this flux is necessary to calculate gas budgets (i.e., O2) to estimate whole-ecosystem metabolism and basin-scale carbon budgets. Empirical data on rates of gas exchange for streams, estuaries, and oceans are readily available. However, there are few data from large rivers and no data from whitewater rapids. We measured gas transfer velocity in the Colorado River, Grand Canyon, as decline in O2 saturation deficit, 7 times in a 28-km segment spanning 7 rapids. The O2 saturation deficit exists because of hypolimnetic discharge from Glen Canyon Dam, located 25 km upriver from Lees Ferry. Gas transfer velocity (k600) increased with slope of the immediate reach. k600 was -1 in flat reaches, while k600 for the steepest rapid ranged 3600-7700 cm h-1, an extremely high value of k600. Using the rate of gas exchange per unit length of water surface elevation (Kdrop, m-1), segment-integrated k600 varied between 74 and 101 cm h-1. Using Kdrop we scaled k600 to the remainder of the Colorado River in Grand Canyon. At the scale corresponding to the segment length where 80% of the O2 exchanged with the atmosphere (mean length = 26.1 km), k600 varied 4.5-fold between 56 and 272 cm h-1 with a mean of 113 cm h-1. Gas transfer velocity for the Colorado River was higher than those from other aquatic ecosystems because of large rapids. Our approach of scaling k600 based on Kdrop allows comparing gas transfer velocity across rivers with spatially heterogeneous morphology.

  3. Purification of monoclonal antibodies from clarified cell culture fluid using Protein A capture continuous countercurrent tangential chromatography.

    Science.gov (United States)

    Dutta, Amit K; Tran, Travis; Napadensky, Boris; Teella, Achyuta; Brookhart, Gary; Ropp, Philip A; Zhang, Ada W; Tustian, Andrew D; Zydney, Andrew L; Shinkazh, Oleg

    2015-11-10

    Recent studies using simple model systems have demonstrated that continuous countercurrent tangential chromatography (CCTC) has the potential to overcome many of the limitations of conventional Protein A chromatography using packed columns. The objective of this work was to optimize and implement a CCTC system for monoclonal antibody purification from clarified Chinese Hamster Ovary (CHO) cell culture fluid using a commercial Protein A resin. Several improvements were introduced to the previous CCTC system including the use of retentate pumps to maintain stable resin concentrations in the flowing slurry, the elimination of a slurry holding tank to improve productivity, and the introduction of an "after binder" to the binding step to increase antibody recovery. A kinetic binding model was developed to estimate the required residence times in the multi-stage binding step to optimize yield and productivity. Data were obtained by purifying two commercial antibodies from two different manufactures, one with low titer (∼ 0.67 g/L) and one with high titer (∼ 6.9 g/L), demonstrating the versatility of the CCTC system. Host cell protein removal, antibody yields and purities were similar to those obtained with conventional column chromatography; however, the CCTC system showed much higher productivity. These results clearly demonstrate the capabilities of continuous countercurrent tangential chromatography for the commercial purification of monoclonal antibody products.

  4. Two-phase flow experiments in a model of the hot leg of a pressurised water reactor. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Tobias; Vallee, Christophe; Lucas, Dirk; Beyer, Matthias; Deendarlianto

    2011-09-15

    In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, a model of the hot leg of a pressurised water reactor was built at FZD. The hot leg model is operated in the pressure chamber of the TOPFLOW test facility, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the chamber. This technique makes it possible to visualise the two-phase flow through large windows, also at reactor-typical pressure levels. In order to optimise the optical observation possibilities, the test section was designed with a rectangular cross-section. Experiments were performed with air and water at 1.5 and 3.0 bar at room temperature as well as with steam and water at 15, 30 and 50 bar and the corresponding saturation temperature (i.e. up to 264 C). The total of 194 runs are divided into 4 types of experiments covering stationary co-current flow, counter-current flow, flow without water circulation and transient counter-current flow limitation (CCFL) experiments. This report provides a detailed documentation of the experiments including information on the experimental setup, experimental procedure, test matrix and on the calibration of the measuring devices. The available data is described and data sheets were arranged for each experiment in order to give an overview of the most important parameters. For the cocurrent flow experiments, water level histograms were arranged and used to characterise the flow in the hot leg. In fact, the form of the probability distribution was found to be sensitive to the boundary conditions and, therefore, is useful for the CFD comparison. Furthermore, the flooding characteristics of the hot leg model plotted in terms of the classical Wallis parameter or Kutateladze number were found to fail to properly correlate the data of the air/water and steam/water series. Therefore, a modified Wallis parameter is proposed, which

  5. Component content distribution profile control in rare earth countercurrent extraction process

    Institute of Scientific and Technical Information of China (English)

    Hui Yang; Fangping Xu; Rongxiu Lu; Yongquan Ding

    2015-01-01

    Considering that the on-line measurement and automatic control of element component content (ECC) are dif-ficult to perform in rare earth cascade extraction process, the ECC distribution profile is dynamical y regulated at al stages to assess the effect of product purity control. Focusing on the theory of countercurrent extraction, the technology parameters and pre-setting flow-rates during the extract process are designed. Under varying process parameters, a novel step by step model is also proposed for each stage to analyze the impact on the distribution profile change. Combining the mass balance model and ECC changing trend at the monitoring stage, the ECC dis-tribution profile can be automatical y regulated by dynamical y compensating the related extract or scrubbing liquid flow-rate. To this end, the required product purity at the two outlets is achieved. Based on Wincc and Matlab dynamic simulators, a specific Pr/Nd cascade extraction process is used to illustrate and demonstrate the application of the present approach.

  6. Sample injection strategy to increase throughput in counter-current chromatography: Case study of Honokiol purification.

    Science.gov (United States)

    Peng, Aihua; Hewitson, Peter; Ye, Haoyu; Zu, Liansuo; Garrard, Ian; Sutherland, Ian; Chen, Lijuan; Ignatova, Svetlana

    2016-12-09

    Counter-current chromatography (CCC) has been widely used as a preparative separation method to purify natural products from plant extracts and fermentation broths. Traditionally, throughput optimization in CCC has focused on sample concentration and sample volume. In this paper sample injection was considered as consisting of three variables: injection flow rate, post-injection flow rate and sample solvent. The effects of these parameters were studied using a honokiol purification from a Magnolia officinalis bark extract as a case study aiming to achieve the highest throughput/yield ratio for greater than 99% purity of this potential anti-cancer drug obtained for submission to the Chinese FDA. An injection method was established that increased the throughput of honokiol by 46.5% (from 3.05g/h to 4.47g/h), and decreased the solvent consumption of mobile phase and stationary phase per gram of honokiol by 40.0% (from 0.68L/g to 0.41L/g) and 48.4% (from 0.40L/g to 0.21L/g) respectively. These results show the importance of understanding the whole injection process when optimizing a given CCC separation.

  7. Experimental study of the decrease in the temperature of an air/water-cooled turbine blade

    Science.gov (United States)

    Ryzhov, A. A.; Sereda, A. V.; Shaiakberov, V. F.; Iskakov, K. M.; Shatalov, Iu. S.

    Results of the full-scale testing of an air/water-cooled deflector-type turbine blade are reported. Data on the decrease in the temperature of the cooling air and of the blade are presented and compared with the calculated values. An analysis of the results indicates that the use of air/water cooling makes it possible to significantly reduce the temperature of the cooling air and of the blade with practically no increase in the engine weight and dimensions.

  8. Novel design for centrifugal counter-current chromatography: VI. Ellipsoid column.

    Science.gov (United States)

    Gu, Dongyu; Yang, Yi; Xin, Xuelei; Aisa, Haji Akber; Ito, Yoichiro

    2015-01-01

    A novel ellipsoid column was designed for centrifugal counter-current chromatography. Performance of the ellipsoid column with a capacity of 3.4 mL was examined with three different solvent systems composed of 1-butanol-acetic acid-water (4:1:5, v/v) (BAW), hexane-ethyl acetate-methanol-0.1 M HCl (1:1:1:1, v/v) (HEMH), and 12.5% (w/w) PEG1000 and 12.5% (w/w) dibasic potassium phosphate in water (PEG-DPP) each with suitable test samples. In dipeptide separation with BAW system, both stationary phase retention (Sf) and peak resolution (Rs) of the ellipsoid column were much higher at 0° column angle (column axis parallel to the centrifugal force) than at 90° column angle (column axis perpendicular to the centrifugal force), where elution with the lower phase at a low flow rate produced the best separation yielding Rs at 2.02 with 27.8% Sf at a flow rate of 0.07 ml/min. In the DNP-amino acid separation with HEMW system, the best results were obtained at a flow rate of 0.05 ml/min with 31.6% Sf yielding high Rs values at 2.16 between DNP-DL-glu and DNP-β-ala peaks and 1.81 between DNP-β-ala and DNP-L-ala peaks. In protein separation with PEG-DPP system, lysozyme and myolobin were resolved at Rs of 1.08 at a flow rate of 0.03 ml/min with 38.9% Sf. Most of those Rs values exceed those obtained from the figure-8 column under similar experimental conditions previously reported.

  9. Experimental study on performance of flow & desulfurisation of a gas-liquid screen scrubber for wet flue gas desulfurization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the paper, the gas-liquid two-phase flow performance and desulfurisation performance of the gasliquid screen scrubber were experimentally studied when limestone wag used as absorbent. Experiments were carried out at varying the flue gas velocity and slurry flux in concurrent and countercurrent tower respectively. The experimental results showed that the flow resistance of absorber increased rapidly with an increase of the flue gas velocity whether in concurrent or in countercurrent tower, and the up trend of the flow resistance in the countercurrent tower was higher than those in the concurrent one. The influence of the flue gas velocity on the flow resistance of absorber was more than those of the slurry flux density. Whether in the concurrent tower or in the countercurrent one, increasing the flue gas velocity or the slurry flux density would enhance the desulphurization efficiency. The influence of the slurry flux density on the desulfurisation efficiency was greater than those of the flue gas velocity.

  10. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume I. Chapters 1-5)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  11. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume II. Chapters 6-10)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  12. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume III. Chapters 11-14)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  13. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume IV. Chapters 15-19)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  14. Preparative separation of grape skin polyphenols by high-speed counter-current chromatography.

    Science.gov (United States)

    Luo, Lanxin; Cui, Yan; Zhang, Shuting; Li, Lingxi; Li, Yuanyuan; Zhou, Peiyu; Sun, Baoshan

    2016-12-01

    To develop an efficient method for large preparation of various individual polyphenols from white grape skins (Fernão Pires; Vitis vinifera) by preparative high-speed counter-current chromatography (HSCCC) and preparative-HPLC, an optimized preparative HSCCC condition with two-phase solvent system composed of Hex-EtOAc-H2O (1:50:50, v/v) was used to separate grape skin polyphenols into various fractions. Both the tail-head and head-tail elution modes were used with a flow rate of 3.0ml/min and a rotary speed of 950rpm. Afterwards, a preparative-HPLC separation was applied to isolate individual polyphenols in each of the fractions from HSCCC. Total of 7 fractions (Fraction A to G) were obtained from grape skin extract by HSCCC. After preparative-HPLC isolation, fifteen individual compounds were obtained, most of which presented high yields and purity (all over 90%). The HSCCC method followed with preparative-HPLC appeared to be convenient and economical, constituting an efficient strategy for the isolation of grape skin polyphenols.

  15. Rapid separation of polysaccharides using a novel spiral coil column by high-speed countercurrent chromatography.

    Science.gov (United States)

    Li, Weili; Wu, Tao

    2016-04-01

    The separation of polysaccharides is time consuming. We developed and optimized a type-J counter-current chromatography system with a novel tri-rotor spiral coil column for the rapid separation of polysaccharides. The optimal composition of an aqueous PEG1000/K2 HPO4 /KH2 PO4 system was found to be 14:16:14 w/w/w where the lower phase was the mobile phase. Optimal performance was achieved at a column rotational speed, temperature, and flow rate of 1200 rpm, 45°C, and 3.0 mL/min, respectively. The mobile phase was pumped from the inner terminal in a ''head-to-tail'' elution mode. Polysaccharide LCP-1 (10.7 mg) was successfully obtained in high purity in one step from 50.0 mg of a crude polysaccharide extracted from the lychee fruit (Litchi chinensis) within 100 min. LCP-1 possess a number-average molecular weight and weight-average molecular weight of 1.05 × 10(5) and 1.59 × 10(5) kDa, respectively. The monosaccharide composition consists of the molar ratio of glucose, galactose, and arabinose of 1.3:3.5:1.

  16. Preparative separation of high-purity cordycepin from Cordyceps militaris(L.) Link by high-speed countercurrent chromatography

    Science.gov (United States)

    Zhu, Licai; Liang, Yong; Lao, Deqiang; Zhang, Tianyou; Ito, Yoichiro

    2009-01-01

    A high-speed counter-current chromatography (HSCCC) technique in a preparative scale has been applied to separate and purify cordycepin from the extract of Cordyceps militaris(L.) Link by a one-step separation. A high efficiency of HSCCC separation was achieved on a two-phase solvent system of n-hexane–n-butanol–methanol–water (23:80:30:155, v/v/v/v) by eluting the lower mobile phase at a flow rate of 2 ml/min under a revolution speed of 850 rpm. HSCCC separation of 216.2 mg crude sample (contained cordycepin at 44.7% purity after 732 cation-exchange resin clean-up) yielded 64.8 mg cordycepin with purity of 98.9% and 91.7% recovery. Identification of the target compound was performed by UV, IR, MS, 1H NMR and 13C NMR. PMID:21643461

  17. Isolation of all-trans lycopene by high-speed counter-current chromatography using a temperature-controlled solvent system.

    Science.gov (United States)

    Baldermann, Susanne; Ropeter, Katharina; Köhler, Nils; Fleischmann, Peter

    2008-05-23

    The effect of solvent system, partition coefficient, retention of stationary phase, column, revolution speed, and flow rate of mobile phase are well known parameters to effect HSCCC (high-speed counter-current chromatography) separations. Temperature effects on chromatographic techniques like HPLC and GC are well studied, but the influence of temperature on CCC solvent systems is hardly investigated. This paper presents the influence of temperature on several key parameters (partition coefficient, settling time, volume ratios) in the hydrophobic HSCCC solvent system hexane:dichloromethane:acetonitrile (30:11:18, v/v/v) used for the isolation of lycopene from tomato paste at 10, 15, 20 and 25 degrees C.

  18. Seasonal variation of the surface North Equatorial Countercurrent (NECC) in the western Pacific Ocean

    Science.gov (United States)

    Zhao, Jun; Li, Yuanlong; Wang, Fan

    2016-11-01

    The North Equatorial Countercurrent (NECC) is an important zonal flow in the upper circulation of the tropical Pacific Ocean, which plays a vital role in the heat budget of the western Pacific warm pool. Using satellite-derived data of ocean surface currents and sea surface heights (SSHs) from 1992 to 2011, the seasonal variation of the surface NECC in the western tropical Pacific Ocean was investigated. It was found that the intensity (INT) and axis position (Y CM ) of the surface NECC exhibit strikingly different seasonal fluctuations in the upstream (128°-136°E) and downstream (145°-160°E) regions. Of the two regions, the seasonal cycle of the upstream NECC shows the greater interannual variability. Its INT and YCM are greatly influenced by variations of the Mindanao Eddy, Mindanao Dome (MD), and equatorial Rossby waves to its south. Both INT and Y CM also show semiannual signals induced by the combined effects of equatorial Rossby waves from the Central Pacific and local wind forcing in the western Pacific Ocean. In the downstream region, the variability of the NECC is affected by SSH anomalies in the MD and the central equatorial Pacific Ocean. Those in the MD region are especially important in modulating the YCM of the downstream NECC. In addition to the SSH-related geostrophic flow, zonal Ekman flow driven by meridional wind stress also plays a role, having considerable impact on INT variability of the surface NECC. The contrasting features of the variability of the NECC in the upstream and downstream regions reflect the high complexity of regional ocean dynamics.

  19. Model calculation of air water counter flow heat and mass transfer and comparison with experimental data%空气与水逆流直接接触热质交换模型计算及与实验比较

    Institute of Scientific and Technical Information of China (English)

    宋垚臻

    2005-01-01

    According to general equations deducted from a model of heat and mass transfer of air and water in direct contact counter flow reported in the author's previous work, the outlet parameters of air and water counter flow through a paper wet pad were calculated by using the MATLAB-software. Comparing the calculation results with experiment data of prior researchers, the deviation of calculated outlet air wet bulb temperature from experimental outlet air wet bulb temperature was less than 10%, the deviation of calculated outlet water temperature from experimental outlet water temperature was less thang 9%, and the deviation of calculated outlet air dry bulb temperature from experimental outlet air dry bulb temperature was less than 10% when NTUh was more than 0. 6. The deviation of calculated outlet air dry bulb temperature from experimental outlet air dry bulb temperature was more than 10% when NTUh was less than 0. 6. The model calculations were in good agreement with experiments and the general equations could be used to design evaporation cooling equipment, such as wet pad and so on.

  20. Estimating pH at the Air/Water Interface with a Confocal Fluorescence Microscope.

    Science.gov (United States)

    Yang, Haiya; Imanishi, Yasushi; Harata, Akira

    2015-01-01

    One way to determine the pH at the air/water interface with a confocal fluorescence microscope has been proposed. The relation between the pH at the air/water interface and that in a bulk solution has been formulated in connection with the adsorption equilibrium and the dissociation equilibrium of the dye adsorbed. Rhodamine B (RhB) is used as a surface-active fluorescent pH probe. The corrected fluorescence spectrum of RhB molecules at the air/water interface with the surface density of 1.0 nmol m(-2) level shows pH-dependent shifts representing an acid-base equilibrium. Two ways to determine the unknown acid-base equilibrium constant of RhB molecules at the air/water interface have been discussed. With surface-tension measurements, the adsorption properties, maximum surface density, and adsorption equilibrium constants were estimated for both cationic and zwitterionic forms of RhB molecules at the air/water interface.

  1. Polystyrene-Polylactide Bottlebrush Block Copolymer at the Air/Water Interface

    Science.gov (United States)

    Zhao, Lei; Byun, Myunghwan; Rzayev, Javid; Lin, Zhiqun

    2010-03-01

    Hydrophobic ultrahigh molecular weight bottlebrush block copolymer and linear block copolymer of polystyrene-polylactide (PS-PLA) were shown to be capable of forming Langmuir monolayers and exhibiting unique assembly behaviors at the air/water interface, which cannot be addressed by the classic theory of Langmuir monolayer of amphiphilic copolymers. New models were proposed to illustrate these intriguing surface behaviors. The self-assembled structure of Langmuir monolayer of bottlebrush block copolymer was determined by a combination of AFM measurement, thermal annealing, and enzymatic degradation experiment. To the best of our knowledge, this is among few studies on hydrophobic block copolymers at the air/water interface. As such, it not only complements the well-known models of self-assembly of amphiphilic block copolymers at the air/water interface but also expands the use of Langmuir-Blodgett (LB) technique to hydrophobic block copolymers.

  2. Characterisation of coastal counter-currents on the inner shelf of the Gulf of Cadiz

    Science.gov (United States)

    Garel, E.; Laiz, I.; Drago, T.; Relvas, P.

    2016-03-01

    At the Gulf of Cadiz (GoC), poleward currents leaning along the coast alternate with coastal upwelling jets of opposite direction. Here the patterns of these coastal countercurrents (CCCs) are derived from ADCP data collected during 7 deployments at a single location on the inner shelf. The multiyear (2008-2014) time-series, constituting ~ 18 months of hourly records, are further analysed together with wind data from several sources representing local and basin-scale conditions. During one deployment, temperature sensors were also installed near the mooring site to examine the vertical thermal stratification associated with periods of poleward flow. These observations indicate that the coastal circulation is mainly alongshore and barotropic. However, a baroclinic flow is often observed shortly at the time of flow inversion to poleward. CCCs develop all year-round and exclusively control the occurrence of warm coastal water during the upwelling season. On average, one poleward flow lasting 3 days was observed every week, corresponding to CCCs during ~ 40% of the time without seasonal variability. Thus, the studied region is distinct from typical upwelling systems where equatorward coastal upwelling jets largely predominate. CCCs often start to develop near the bed and are frequently associated with 2-layer cross-shore flows characteristic of downwelling conditions (offshore near the bed). In general, the action of alongshore wind stress alone does not justify the development of CCCs. The coastal circulation is best correlated and shows the highest coherence with south-eastward wind in the basin that proceeds from the rotation of southward wind at the West coast of Portugal, hence suggesting a dominant control of large-scale wind conditions. In agreement, wavelet analyses indicate that CCCs are best correlated with alongshore wind occurring in a band period characteristic of the upwelling system (8-32 days). Furthermore, in the absence of wind coastal currents tend

  3. Steady-state and non-steady state operation of counter-current chromatography devices.

    Science.gov (United States)

    Kostanyan, Artak E; Ignatova, Svetlana N; Sutherland, Ian A; Hewitson, Peter; Zakhodjaeva, Yulya A; Erastov, Andrey A

    2013-11-01

    Different variants of separation processes based on steady-state (continuous sample loading) and non-steady state (batch) operating modes of CCC columns have been analyzed and compared. The analysis is carried out on the basis of the modified equilibrium cell model, which takes into account both mechanisms of band broadening - interphase mass transfer and axial mixing. A full theoretical treatment of the intermittent counter-current chromatography with short sample loading time is performed. Analytical expressions are presented allowing the simulation of the intermittent counter-current chromatography separations for various experimental conditions. Chromatographic and extraction separations have been compared and advantages and disadvantages of the two methods have been evaluated. Further technical development of the CCC machines to implement counter-current extraction separations is considered.

  4. Intermittent counter-current extraction-Equilibrium cell model, scaling and an improved bobbin design.

    Science.gov (United States)

    Hewitson, Peter; Sutherland, Ian; Kostanyan, Artak E; Voshkin, Andrei A; Ignatova, Svetlana

    2013-08-16

    This paper describes an equilibrium cell model for intermittent counter-current extraction that is analytically solved for the first time for continuous sample injection between a pair of columns. The model is compared with practice for injections of a model mixture of compounds on a standard high-performance counter-current chromatography instrument giving good agreement for compound elution order and the times to maximum concentration for the eluted components. An improved design of end fittings for the counter-current chromatography bobbins is described which permits on-column switching of the mobile and stationary phases. This on-column switching successfully eliminates the displaced stationary phase seen in fractions when operating ICcE with standard flying leads and gives a 6% reduction in the retention time of compounds and improved resolution due to the elimination of the time delay required to pump the previous mobile phase from standard flying leads.

  5. Nanowire and Mesh Conformations of Diblock Copolymer Blends at the Air/Water Interface

    NARCIS (Netherlands)

    Seo, Young-Soo; Kim, K.S.; Galambos, Arielle; Lammertink, R.G.H.; Vancso, G.J.; Sokolov, J.; Rafailovich, M.

    2004-01-01

    We investigated the structures formed when blends of poly(styrene-b-ferrocenyl silane) (PS-b-FS) and poly(styrene-b-2-vinyl pyridine) (PS-b-P2VP) were spread at the air/water interface. The results demonstrated that new structures were formed which were distinct from those formed when either of the

  6. Hydrodynamics of a self-propelled camphor boat at the air-water interface

    Science.gov (United States)

    Akella, Sathish; Singh, Dhiraj; Singh, Ravi; Bandi, Mahesh

    2015-11-01

    A camphor tablet, when placed at the air-water interface undergoes sublimation and camphor vapour spreads radially outwards across the surface due to Marangoni forces. This steady camphor influx from tablet onto the air-water interface is balanced by the camphor outflux due to evaporation. When spontaneous fluctuations in evaporation break the axial symmetry of Marangoni force acting radially outwards, the camphor tablet is propelled like a boat along the water surface. We report experiments on the hydrodynamics of a self-propelled camphor boat at air-water interfaces. We observe three different modes of motion, namely continuous, harmonic and periodic, due to the volatile nature of camphor. We explain these modes in terms of ratio of two time-scales: the time-scale over which viscous forces are dominant over the Marangoni forces (τη) and the time-scale over which Marangoni forces are dominant over the viscous forces (τσ). The continuous, harmonic and periodic motions are observed when τη /τσ ~ 1 , τη /τσ >= 1 and τη /τσ >> 1 respectively. Experimentally, the ratio of the time scales is varied by changing the interfacial tension of the air-water interface using Sodium Dodecyl Sulfate. This work was supported by the Collective Interactions Unit, OIST Graduate University.

  7. Molecular details of ovalbumin-pectin complexes at the air/water interface: A spectroscopic study

    NARCIS (Netherlands)

    Kudryashova, E.V.; Visser, A.J.W.G.; Hoek, A. van; Jongh, H.H.J. de

    2007-01-01

    To stabilize air-water interfaces, as in foams, the adsorption of surface-active components is a prerequisite. An approach to controlling the surface activity of proteins is noncovalent complex formation with a polyelectrolyte in the bulk phase. The molecular properties of egg white ovalbumin in a c

  8. Spreading of partially crystallized oil droplets on an air/water interface

    NARCIS (Netherlands)

    Hotrum, N.E.; Cohen Stuart, M.A.; Vliet, van T.; Aken, van G.A.

    2004-01-01

    The influence of crystalline fat on the amount and rate of oil spreading out of emulsion droplets onto either a clean or a protein-covered air/water interface was measured for ß-lactoglobulin stabilized emulsions prepared with either anhydrous milk fat or a blend of hydrogenated palm fat and sunflow

  9. Numerical Investigation of Transmission of Low Frequency Sound Through a Smooth Air-water Interface

    Institute of Scientific and Technical Information of China (English)

    Parviz Ghadimi; Alireza Bolghasi; Mohammad A Feizi Chekab; Rahim Zamanian

    2015-01-01

    It is the traditional belief that sound transmission from water to the air is very weak due to a large contrast between air and water impedances. Recently, the enhanced sound transmission and anomalous transparency of air-water interface have been introduced. Anomalous transparency of air-water interface states that the sound generated by a submerged shallow depth monopole point source localized at depths less than 1/10 sound wavelength, can be transmitted into the air with omni-directional pattern. The generated sound has 35 times higher power compared to the classical ray theory prediction. In this paper, sound transmission through air-water interface for a localized underwater shallow depth source is examined. To accomplish this, two-phase coupled Helmholtz wave equations in two-phase media of air-water are solved by the commercial finite element based COMSOL Multiphysics software. Ratios of pressure amplitudes of different sound sources in two different underwater and air coordinates are computed and analyzed against non-dimensional ratio of the source depth (D) to the sound wavelength (λ). The obtained results are compared with the experimental data and good agreement is displayed.

  10. Understanding the structure of hydrophobic surfactants at the air/water interface from molecular level.

    Science.gov (United States)

    Zhang, Li; Liu, Zhipei; Ren, Tao; Wu, Pan; Shen, Jia-Wei; Zhang, Wei; Wang, Xinping

    2014-11-25

    Understanding the behavior of fluorocarbon surfactants at the air/water interface is crucial for many applications, such as lubricants, paints, cosmetics, and fire-fighting foams. In this study, molecular dynamics (MD) simulations were employed to investigate the microscopic properties of non-ionic fluorocarbon surfactants at the air/water interface. Several properties, including the distribution of head groups, the distribution probability of the tilt angle between hydrophobic tails with respect to the xy plane, and the order parameter of surfactants, were computed to probe the structure of hydrophobic surfactants at the air/water interface. The effects of the monomer structure on interfacial phenomena of non-ionic surfactants were investigated as well. It is observed that the structure of fluorocarbon surfactants at the air/water interface is more ordered than that of hydrocarbons, which is dominated by the van der Waals interaction between surfactants and water molecules. However, replacing one or two CF2 with one or two CH2 group does not significantly influence the interfacial structure, suggesting that hydrocarbons may be promising alternatives to perfluorinated surfactants.

  11. High-speed countercurrent chromatography for purification of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ying Cai; Zhi Hong Yan; Ying Chun Lv; Min Zi; Li Ming Yuan

    2008-01-01

    A new chromatographic purification of single-walled carbon nanotubes using high-speed countercurrent chromatography is reported.The purification was accomplished on the basis of experiment that dispersed the single-walled carbon nanotubes with sodium dodecyl sulfate,and the result mixture was separated using the two phase system composed of n-butanol/water=1/1 (v/v).The sizes of SWNTs separated were observed by scanning electron microscopy.The results demonstrated that the high-speed countercurrent chromatography possessed a good efficency for purification of single-walled carbon nanotubes.

  12. Axillary artery counter-current aortography in the newborn with aortic arch obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lau, K.C.; Lo, R.N.S.; Leung, M.P.

    1989-08-01

    13 newborn infants with aortic coarctation were evaluated by counter-current aortographic technique. The right radial or brachial artery approach (2 cases in each group) did not give successful aortic arch imaging while the right axiallary artery approach resulted in adequate imaging in each of 9 cases investigated. In 2, the axillary artery was transiently weakened but returned to normal within 24 hours. No other complications were encountered. Axillary artery counter-current aortography is a safe and relatively non-invasive procedure which can be used to image the aortic arch in the newborn babies when other non-invasive diagnosis of aortic arch obstruction is tentative. (orig.).

  13. Fractionation of wheat gliadins by counter-current distribution using an organic two-phase system.

    Science.gov (United States)

    Truust, H; Johansson, G

    1998-06-26

    A liquid liquid two-phase system based on N,N-dimethylformamide and the two polymers, poly(ethyleneglycol) and Ficoll, useful for partitioning of hydrophobic proteins, has been developed. The system has been applied to a counter-current distribution process in 56 steps for analysing the heterogeneity of proteins extracted with N,N-dimethylformamide from wheat flour. The counter-current distribution patterns of proteins, extracted from eight kinds of wheat, have been analysed. The minimum number of hypothetical proteins necessary to describe the patterns was found to be seven. The relative amount of these hypothetical components varied among the wheats.

  14. Experimental investigation on the droplet entrainment from interfacial waves in air-water horizontal stratified flow

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, J. H.; Ha, K. S. [KAERI, Daejeon (Korea, Republic of); Jeong, H. Y. [Sejong University, Seoul (Korea, Republic of)

    2014-10-15

    The main purpose of the wire is to avoid collision between adjacent rods.. Furthermore, a vortex induced vibration can be mitigated by wire spacers. In this study, the RANS based CFD methodology using an innovative grid generation has been evaluated in the 7-pin, 37-pin, and 217-pin wire wrapped fuel assembly, which is using the general purpose commercial CFD code, CFX. The RANS-based CFD methodology using the innovative hexagonal grid generation with the in-house code and the GGI function of the CFX code has been evaluated in the 7-pin, 37-pin, and 217-pin wire wrapped fuel assembly. SFR (Sodium-cooled Fast Reactor) system is one of the nuclear reactors in which a recycling of transuranics (TRUs) by reusing spent nuclear fuel sustains the fission chain reaction. This situation strongly motivated Korea Atomic Energy Research Institute (KAERI) to start a Prototype Gen Sodium-cooled Fast Reactor (PGSFR) design project under the national nuclear R and D program. Generally, SFR system has tight package of the fuel bundle and the high power density. The fuel assembly of SFR system is consisted of wire wrapped fuel bundles with triangular loose array. The bundles of the SFR fuel assembly usually consisted of rods and wire spacers. The innovative RANS-based CFD methodology can remarkably reduce the number of meshes. Grid sensitivity study of the wall y grid scale with SST turbulence model in 7-pin fuel assembly has been carried out, and the uncertainty of friction factor was under the 6.0%. It has been validated that the GGI function of CFX code is very conservative interpolation function. The innovative RANS based CFD methodology can be successfully extended to real 217- pin wire-wrapped fuel assembly of KAERI 2014 PGSFR.

  15. Combination of integrated expanded bed adsorption chromatography and countercurrent chromatography for the direct extraction and purification of pseudohypericin and hypericin from St. John's wort (Hypericum perforatum L.).

    Science.gov (United States)

    Cai, Fanfan; Li, Yang; Zhang, Min; Zhang, Hongyang; Wang, Yuerong; Hu, Ping

    2015-08-01

    St. John's wort has attracted particular attention because of its beneficial effects as an antidepressant, antiviral, and anticancer agent. A method for the combination of integrated expanded bed adsorption chromatography and countercurrent chromatography for the simultaneous extraction and purification of pseudohypericin and hypericin from the herb is presented in this paper. Firstly, the constituents were extracted and directly adsorbed by expanded bed adsorption chromatography under optimal conditions. The stepwise elution was then performed by expanded bed adsorption chromatography that enriched the targets with higher purities and recoveries compared to other methods. Secondly, the eluent fractions from expanded bed adsorption chromatography were further separated by two-step high-speed countercurrent chromatography. A two-step high-speed countercurrent chromatography method with a biphasic solvent system composed of n-hexane/ethyl acetate/methanol/water with a volume ratio of 1:2:1:2 was performed by stepwise changing the flow rate of the mobile phase. Consequently, 5.6 mg of pseudohypericin and 2.2 mg of hypericin with purities of 95.5 and 95.0%, respectively, were successfully obtained from 40 mg of crude sample.

  16. Two-phase Lattice Boltzmann modelling of streaming potentials: influence of the air-water interface on the electrokinetic coupling

    Science.gov (United States)

    Fiorentino, Eve-Agnès; Toussaint, Renaud; Jouniaux, Laurence

    2017-02-01

    The streaming potential phenomenon is an electrokinetic effect that occurs in porous media. It is characterized by an electrokinetic (EK) coefficient. The aim of this paper is to simulate the EK coefficient in unsaturated conditions using the Lattice Boltzmann method in a 2-D capillary channel. The multiphase flow is simulated with the model of Shan & Chen. The Poisson-Boltzmann equation is solved by implementing the model of Chai & Shi. The streaming potential response shows a non-monotonous behaviour due to the combination of the increase of charge density and decrease of flow velocity with decreasing water saturation. Using a ζ potential of -20 mV at the air-water interface, an enhancement of a factor 5-30 of the EK coefficient, compared to the saturated state, can be observed due to the positive charge excess at this interface which is magnified by the fluid velocity away from the rock surface. This enhancement is correlated to the fractioning of the bubbles, and to the dynamic state of these bubbles, moving or entrapped in the crevices of the channel.

  17. Effects of Gravity and Inlet Location on a Two-Phase Countercurrent Imbibition in Porous Media

    Directory of Open Access Journals (Sweden)

    M. F. El-Amin

    2012-01-01

    Full Text Available We introduce a numerical investigation of the effect of gravity on the problem of two-phase countercurrent imbibition in porous media. We consider three cases of inlet location, namely, from, side, top, and bottom. A 2D rectangular domain is considered for numerical simulation. The results indicate that gravity has a significant effect depending on open-boundary location.

  18. Counter-current CO2 purification of partially deacylated sunflower oil

    Science.gov (United States)

    High oleic sunflower oil was partially deacylated by propanolysis to produce a mixture of diglycerides and triglycerides. To remove by-product fatty acid propyl esters (FAPEs) from this reaction mixture, a liquid carbon dioxide (L-CO2) counter-current fractionation method was developed. The fracti...

  19. Counter-current carbon dioxide purification of partially deacylated sunflower oil

    Science.gov (United States)

    High oleic sunflower oil was partially deacylated by propanolysis to produce a mixture of diglycerides and triglycerides. To remove by-product fatty acid propyl esters (FAPEs) from this reaction mixture, a liquid carbon dioxide (L-CO2) counter-current fractionation method was developed. The fracti...

  20. A novel apparatus for countercurrent sorption separation processes using fibrous sorbents

    NARCIS (Netherlands)

    Diederen, A.M.; Zee, G. van; Veenman, A.W.; Graauw, J. de

    1998-01-01

    This paper discusses a technical feasibility study on continuous countercurrent sorption equipment using mechanically transported fibrous sorbent materials such as fiber beds and open-cell foam. A pilot unit was developed and tested and the apparatus performed adequately. Under the conditions applie

  1. Effects of gravity and inlet location on a two-phase countercurrent imbibition in porous media

    KAUST Repository

    El-Amin, Mohamed

    2012-01-01

    We introduce a numerical investigation of the effect of gravity on the problem of two-phase countercurrent imbibition in porous media. We consider three cases of inlet location, namely, from, side, top, and bottom. A 2D rectangular domain is considered for numerical simulation. The results indicate that gravity has a significant effect depending on open-boundary location.

  2. The heat-transfer performance of gas—solid trickle flow over a regularly stacked packing

    NARCIS (Netherlands)

    Verver, A.B.; Swaaij, van W.P.M.

    1986-01-01

    The heat-transfer behaviour of a countercurrent gas—solid trickle flow contactor is studied, using coarse sand particles as the solids phase. Experimental data on the overall heat-transfer rate constant between the gas flow and the solid particle flow were obtained in a 0.15 m square cross-section c

  3. WEXA: exergy analysis for increasing the efficiency of air/water heat pumps - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gasser, L.; Wellig, B.; Hilfiker, K.

    2008-04-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of a study at the made by the Engineering and Architecture department at the Lucerne University of Applied Sciences and Arts. The subject of the WEXA study (Waermepumpen-Exergie-Analyse - heat pump exergy analysis) is the analysis of the operation of air/water heat-pumps using exergy analysis methods. The basic thermodynamics of heating systems using heat-pumps is discussed. The exergy analyses and exergy balances for the various components and processes of an air/water heat-pump are presented and discussed. Comparisons are presented for heat-pumps with on/off and continuous control systems for their compressors and fans. The paper is concluded with a collection of appendices on the subject.

  4. Semi-industrial isolation of salicin and amygdalin from plant extracts using slow rotary counter-current chromatography.

    Science.gov (United States)

    Du, Qizhen; Jerz, Gerold; Ha, Yangchun; Li, Lei; Xu, Yuanjin; Zhang, Qi; Zheng, Qunxiong; Winterhalter, Peterb; Ito, Yoichiro

    2005-05-13

    Salicin in the bark extract of Salix alba and amygdalin in the fruit extract of Semen armeniacae were each separated by slow rotary counter-current chromatography (SRCCC). The apparatus was equipped with a 40-L column made of 17 mm i.d. convoluted Teflon tubing. A 500g amount of crude extract containing salicin at 13.5% was separated yielding 63.5 g of salicin at 95.3% purity in 20h using methyl tert-butyl ether-l-butanol (1:3) saturated by methanol-water (1:5) as a stationary phase and methanol-water (1:5) saturated by methyl tert-butyl ether-1-butanol (1:3) as a mobile phase. A 400g amount of crude extract containing amygdalin at 55.3% was isolated to yield 221.2g of amygdalin at 94.1% purity in 19h using ethyl acetate-1-butanol (1:2) saturated by water as a stationary phase and water saturated by ethyl acetate-1-butanol (1:2) as a mobile phase. The flow rate of the mobile phase was 50 ml/min. The results show that industrial SRCCC separation of salicin and amygdalin is feasible using a larger column at a higher flow rate of the mobile phase.

  5. Two-Step Separation of Nostotrebin 6 from Cultivated Soil Cyanobacterium (Nostoc sp. by High Performance Countercurrent Chromatography

    Directory of Open Access Journals (Sweden)

    José Cheel

    2014-06-01

    Full Text Available High performance countercurrent chromatography (HPCCC was successfully applied for the separation of nostotrebin 6 from cultivated soil cyanobacteria in a two-step operation. A two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (4:5:4:5, v/v/v/v was employed for the HPCCC separation. In the first-step operation, its neutral upper phase was used as stationary phase and its basic lower phase (1% NH3 in lower phase was employed as mobile phase at a flow rate of 1 mL/min. In the second operation step, its neutral upper phase was used as stationary phase, whereas both its neutral lower phase and basic lower phase were employed as mobile phase with a linear gradient elution at a flow rate of 0.8 mL/min. The revolution speed and temperature of the separation column were 1,000 rpm and 30 °C, respectively. Using HPCCC followed by clean-up on Sephadex LH-20 gel, 4 mg of nostotrebin 6 with a purity of 99% as determined by HPLC/DAD-ESI-HRMS was obtained from 100 mg of crude extract. The chemical identity of the isolated compound was confirmed by comparing its spectroscopic data (UV, ESI-HRMS, ESI-HRMS2 with those of an authentic standard and data available in the literature.

  6. Correlation of Oil-Water and Air-Water Contact Angles of Diverse Silanized Surfaces and Relationship to Fluid Interfacial Tensions

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Dehoff, Karl J.; Warner, Marvin G.; Pittman, Jonathan W.; Wietsma, Thomas W.; Zhang, Changyong; Oostrom, Martinus

    2012-02-24

    The use of air-water, {Theta}{sub wa}, or air-liquid contact angles is customary in surface science, while oil-water contact angles {Theta}{sub ow}, are of paramount importance in subsurface multiphase flow phenomena including petroleum reocovery, nonaqueous phase liquid fate and transport, and geological carbon sequestration. In this paper we determine both the air-water and oil-water contact angles of silica surfaces modified with a diverse selection of silanes, using hexadecane as the oil. The silanes included alkylsilanes, alkylarylsilanes, and silanes with alkyl or aryl groups that are functionalized with heteroatoms such as N, O, and S. These silanes yielded surfaces with wettabilities from water-wet to oil wet, including specific silanized surfaces functionalized with heteroatoms that yield intermediate wet surfaces. The oil-water contact angles for clean and silanized surfaces, excluding one partially fluorinated surface, correlate linearly with air-water contact angles with a slope of 1.41 (R = 0.981, n = 13). These data were used to examine a previously untested theoretical treatment relating air-water and oil-water contact angles in terms of fluid interfacial energies. Plotting the cosines of these contact angles against one another, we obtain a linear relationship in excellent agreement with the theoretical treatment; the data fit cos {Theta}{sub ow} = 0.667 cos {Theta}{sub ow} + 0.384 (R = 0.981, n = 13), intercepting cos {Theta}{sub ow} = -1 at -0.284. The theoretical slope, based on the fluid interfacial tensions {Theta}{sub wa}, {Theta}{sub ow}, and {Theta}{sub oa}, is 0.67. We also demonstrate how silanes can be used to alter the wettability of the interior of a pore network micromodel device constructed in silicon/silica with a glass cover plate. Such micromodels are used to study multiphase flow phenomena. The contact angle of the resulting interior was determined in situ. An intermediate wet micromodel gave a contact angle in excellent agreement

  7. Interfacial air/water proton conduction from long distances by sulfolobus solfataricus archaeal bolaform lipids.

    Science.gov (United States)

    Vilalta, I; Gliozzi, A; Prats, M

    1996-08-15

    The stability, structural organization, and the ability to transfer protons long distances have been investigated in monolayers formed from archael bolaform lipids at the air/water interface. The lipids employed were the fractions GroR2Gro (R represents an acyl group with variable chain length typically consisting of 0-4 cyclopentane rings and 40 isoprenoid residues) and GroR2GroNon-Ol (Non-ol represents nonitol) extracted from Sulfolobus solfataricus by hydrolysis of the cytoplasmic membrane. GroR2-GroNon-ol films exhibit a very peculiar behaviour: the monolayer surface pressure increases with time, regardless of its low or high initial value. This finding is related to the possibility of GroR2GroNon-ol molecules to assume an upright (a metastable) or a U-shaped (stable) configuration. In the gaseous state and in the collapsed state of the film, no lateral proton conduction was observed. However, in the pressure range 0 < pi < 25 mN/m for GroR2Gro and 0 < pi < 30 mN/m for GroR2GroNon-ol monolayers, a lateral proton conduction at the air/water interface was observed. The structural organization of these bipolar lipids at the air/water interface can be related to the lateral proton conduction; it is possible to conclude that whatever configuration these lipids may adopt, they are able to structure the air/water interface in a hydrogen bond network that supports lateral proton conduction. This process may be ascribed to a percolation phenomenon occurring when the polar lipid head groups form a structured lattice of hydrogen bonds.

  8. Efficient air-water heat pumps for high temperature lift residential heating, including oil migration aspects

    OpenAIRE

    Zehnder, Michele; Favrat, Daniel

    2005-01-01

    This thesis presents a system approach with the aim to develop improved concepts for small capacity, high temperature lift air-water heat pumps. These are intended to replace fuel fired heating systems in the residential sector, which leads to a major reduction of the local greenhouse gas emissions. Unfavorable temperature conditions set by the existing heat distribution systems and by the use of atmospheric air, as the only accessible heat source, have to be overcome. The proposed concepts a...

  9. Interactive Effect of Air-Water Ratio and Temperature on the Air Stripping of Benzene

    Directory of Open Access Journals (Sweden)

    M. E. Abdullahi

    2014-06-01

    Full Text Available High cost of pilot scale studies has led engineers to use simulation to study the factors that affect process performance. This study focuses on the interactive effect of air water ratio and temperature on the removal of volatile organic compounds from polluted water using packed column air stripper taking benzene as a case study. The process governing equations developed based on two-film model of mass transfer were solved using MATLAB and a surface response plot was done. The mass transfer coefficient increased from 0.1237x10-5 to 0.1932x10-5 s-1 as the temperature was raised from 293 to 323 K. Also, the Henry’s constant increased from 228.59 to 883.36 K as the temperature was raised from 293 to 323 K. Benzene removal efficiencies of over 99% were obtained for all combinations of temperature and air-water ratio. The result also indicated that air stripping of benzene from wastewater is most dependent on temperature and moderately on air-water ratio.

  10. Micrometeorological measurement of hexachlorobenzene and polychlorinated biphenyl compound air-water gas exchange in Lake Superior and comparison to model predictions

    Directory of Open Access Journals (Sweden)

    M. D. Rowe

    2012-01-01

    Full Text Available Air-water exchange fluxes of persistent, bioaccumulative and toxic (PBT substances are frequently estimated using the Whitman two-film (W2F method, but micrometeorological flux measurements of these compounds over water are rarely attempted. We measured air-water exchange fluxes of hexachlorobenzene (HCB and polychlorinated biphenyls (PCBs on 14 July 2006 in Lake Superior using the modified Bowen ratio (MBR method. Measured fluxes were compared to estimates using the W2F method, and to estimates from an Internal Boundary Layer Transport and Exchange (IBLTE model that implements the NOAA COARE bulk flux algorithm and gas transfer model. We reveal an inaccuracy in the estimate of water vapor transfer velocity that is commonly used with the W2F method for PBT flux estimation, and demonstrate the effect of use of an improved estimation method. Flux measurements were conducted at three stations with increasing fetch in offshore flow (15, 30, and 60 km in southeastern Lake Superior. This sampling strategy enabled comparison of measured and predicted flux, as well as modification in near-surface atmospheric concentration with fetch, using the IBLTE model. Fluxes estimated using the W2F model were compared to fluxes measured by MBR. In five of seven cases in which the MBR flux was significantly greater than zero, concentration increased with fetch at 1-m height, which is qualitatively consistent with the measured volatilization flux. As far as we are aware, these are the first reported micrometeorological air-water exchange flux measurements of PCBs.

  11. Micrometeorological measurement of hexachlorobenzene and polychlorinated biphenyl compound air-water gas exchange in Lake Superior and comparison to model predictions

    Directory of Open Access Journals (Sweden)

    M. D. Rowe

    2012-05-01

    Full Text Available Air-water exchange fluxes of persistent, bioaccumulative and toxic (PBT substances are frequently estimated using the Whitman two-film (W2F method, but micrometeorological flux measurements of these compounds over water are rarely attempted. We measured air-water exchange fluxes of hexachlorobenzene (HCB and polychlorinated biphenyls (PCBs on 14 July 2006 in Lake Superior using the modified Bowen ratio (MBR method. Measured fluxes were compared to estimates using the W2F method, and to estimates from an Internal Boundary Layer Transport and Exchange (IBLTE model that implements the NOAA COARE bulk flux algorithm and gas transfer model. We reveal an inaccuracy in the estimate of water vapor transfer velocity that is commonly used with the W2F method for PBT flux estimation, and demonstrate the effect of use of an improved estimation method. Flux measurements were conducted at three stations with increasing fetch in offshore flow (15, 30, and 60 km in southeastern Lake Superior. This sampling strategy enabled comparison of measured and predicted flux, as well as modification in near-surface atmospheric concentration with fetch, using the IBLTE model. Fluxes estimated using the W2F model were compared to fluxes measured by MBR. In five of seven cases in which the MBR flux was significantly greater than zero, concentration increased with fetch at 1-m height, which is qualitatively consistent with the measured volatilization flux. As far as we are aware, these are the first reported ship-based micrometeorological air-water exchange flux measurements of PCBs.

  12. Thermal Characteristics of Air-Water Spray Impingement Cooling of Hot Metallic Surface under Controlled Parametric Conditions

    Institute of Scientific and Technical Information of China (English)

    Santosh Kumar Nayak; Purna Chandra Mishra

    2016-01-01

    Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper.The controlling input parameters investigated were the combined air and water pressures,plate thickness,water flow rate,nozzle height from the target surface and initial temperature of the hot surface.The effects of these input parameters on the important thermal characteristics such as heat transfer rate,heat transfer coefficient and wetting front movement were measured and examined.Hot flat plate samples of mild steel with dimension 120 mm in length,120 mm breadth and thickness of 4 mm,6 mm,and 8 mm respectively were tested.The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface.Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e,4 mm thick plates.Increase in the nozzle height reduced the heat transfer efficiency of spray cooling.At an inlet water pressure of 4 bar and air pressure of 3 bar,maximum cooling rates 670℃/s and average cooling rate of 305.23℃/s were achieved for a temperature of 850℃ of the steel plate.

  13. Interaction between heterogeneous environmental quality domains (air, water, land, socio-demographic and built environment) on preterm birth.

    Science.gov (United States)

    Environmental exposures are often measured individually, though many occur in tandem. To address aggregate exposures, a county-level Environmental Quality Index (EQI) representing five environmental domains (air, water, land, built and sociodemographic) was constructed. Recent st...

  14. Ecosystem Metabolism and Air-Water Fluxes of Greenhouse Gases in High Arctic Wetland Ponds

    Science.gov (United States)

    Lehnherr, I.; Venkiteswaran, J.; St. Louis, V. L.; Emmerton, C.; Schiff, S. L.

    2012-12-01

    Freshwater lakes and wetlands can be very productive systems on the Arctic landscape compared to terrestrial tundra ecosystems and provide valuable resources to many organisms, including waterfowl, fish and humans. Rates of ecosystem productivity dictate how much energy flows through food webs, impacting the abundance of higher-level organisms (e.g., fish), as well as the net carbon balance, which determines whether a particular ecosystem is a source or sink of carbon. Climate change is predicted to result in warmer temperatures, increased precipitation and permafrost melting in the Arctic and is already altering northern ecosystems at unprecedented rates; however, it is not known how freshwater systems are responding to these changes. To predict how freshwater systems will respond to complex environmental changes, it is necessary to understand the key processes, such as primary production and ecosystem respiration, that are driving these systems. We sampled wetland ponds (n=8) and lakes (n=2) on northern Ellesmere Island (81° N, Nunavut, Canada) during the open water season for a suite of biogeochemical parameters, including concentrations of dissolved gases (O2, CO2, CH4, N2O) as well as stable-isotope ratios of dissolved inorganic carbon (δ13C-DIC), dissolved oxygen (δ18O-DO), and water (δ18O-H2O). We will present rates of primary production and ecosystem respiration, modeled from the concentration and stable isotope ratios of DIC and DO, as well as air-water gas exchange of greenhouse gases in these high Arctic ponds and lakes. Preliminary results demonstrate that ecosystem metabolism in these ponds was high enough to result in significant deviations in the isotope ratios of DIC and DO from atmospheric equilibrium conditions. In other words ecosystem rates of primary production and respiration were faster than gas exchange even in these small, shallow, well-mixed ponds. Furthermore, primary production was elevated enough at all sites except Lake Hazen, a

  15. [Isolation and preparation of gallic acid from Terminalia chebula Retz. with high-speed counter-current chromatography].

    Science.gov (United States)

    Li, Zhongqin; Li, Qiuyun; Jiang, Xinglong; Zhang, Kun; Guan, Ruizhang

    2014-12-01

    A separation method based on high-speed counter-current chromatography (HSCCC) has been established for the isolation and preparation of gallic acid from the ethanol extract of Terminalia chebula Retz. After comparing five kinds of solvent protocols of HSCCC, the two-phase system of n-hexane-ethyl acetate-methanol-water (1:5:1:5, v/v/v/v) was finally chosen as the operating solvent of HSCCC for the separation of gallic acid, in which the lower phase was used as the mobile phase and the upper phase as stationary phase. The detection in the experiments was performed with an ultraviolet detector at 254 nm. Under the conditions of rotation speed of 850 r/min, lower phase flow rate of 2 mL/min, four peaks (I/II/III/IV) were displayed on HSCCC chromatogram. Among them, only peak III contained a large amount of gallic acid (about 96. 40%), which was confirmed by electrospray ionization mass spectrometry (ESI-MS) and high performance liquid chromatographic (HPLC) analysis. As much as 8. 6 mg of gallic acid was obtained from 100 mg of the ethanol extract of Terminalia chebula Retz., indicating the method is simple, robust and efficient for the preparation of gallic acid.

  16. Chromatographic separation of three monoclonal antibody variants using multicolumn countercurrent solvent gradient purification (MCSGP).

    Science.gov (United States)

    Müller-Späth, Thomas; Aumann, Lars; Melter, Lena; Ströhlein, Guido; Morbidelli, Massimo

    2008-08-15

    Multicolumn countercurrent solvent gradient purification (MCSGP) is a continuous chromatographic process developed in recent years (Aumann and Morbidelli, 2007a; Aumann et al., 2007) that is particularly suited for applications in the field of bioseparations. Like batch chromatography, MCSGP is suitable for three-fraction chromatographic separations and able to perform solvent gradients but it is superior in terms of solvent consumption, yield, purity, and productivity due to the countercurrent movement of the liquid and the solid phases. In this work, the MCSGP process is applied to the separation of three monoclonal antibody variants on a conventional preparative cation exchange resin. The experimental process performance was compared to simulations based on a lumped kinetic model. Yield and purity values of the target variant of 93%, respectively were obtained experimentally. The batch reference process was clearly outperformed by the MCSGP process.

  17. Product sampling during transient continuous countercurrent hydrolysis of canola oil and development of a kinetic model

    KAUST Repository

    Wang, Weicheng

    2013-11-01

    A chemical kinetic model has been developed for the transient stage of the continuous countercurrent hydrolysis of triglycerides to free fatty acids and glycerol. Departure functions and group contribution methods were applied to determine the equilibrium constants of the four reversible reactions in the kinetic model. Continuous countercurrent hydrolysis of canola oil in subcritical water was conducted experimentally in a lab-scale reactor over a range of temperatures and the concentrations of all neutral components were quantified. Several of the rate constants in the model were obtained by modeling this experimental data, with the remaining determined from calculated equilibrium constants. Some reactions not included in the present, or previous, hydrolysis modeling efforts were identified from glycerolysis kinetic studies and may explain the slight discrepancy between model and experiment. The rate constants determined in this paper indicate that diglycerides in the feedstock accelerate the transition from "emulsive hydrolysis" to "rapid hydrolysis". © 2013 Elsevier Ltd.

  18. Monolayer film behavior of lipopolysaccharide from Pseudomonas aeruginosa at the air-water interface.

    Science.gov (United States)

    Abraham, Thomas; Schooling, Sarah R; Beveridge, Terry J; Katsaras, John

    2008-10-01

    Lipopolysaccharide (LPS) is an essential biomacromolecule making up approximately 50% of the outer membrane of gram-negative bacteria. LPS chemistry facilitates cellular barrier and permeability functions and mediates interactions between the cell and its environment. To better understand the local interactions within LPS membranes, the monolayer film behavior of LPS extracted from Pseudomonas aeruginosa, an opportunistic pathogen of medical importance, was investigated by Langmuir film balance. LPS formed stable monolayers at the air-water interface and the measured lateral stresses and modulus (rigidity) of the LPS film in the compressed monolayer region were found to be appreciable. Scaling theories for two-dimensional (2D) polymer chain conformations were used to describe the pi-A profile, in particular, the high lateral stress region suggested that the polysaccharide segments reside at the 2D air-water interface. Although the addition of monovalent and divalent salts caused LPS molecules to adopt a compact conformation at the air-water interface, they did not appear to have any influence on the modulus (rigidity) of the LPS monolayer film under biologically relevant stressed conditions. With increasing divalent salt (CaCl2) content in the subphase, however, there is a progressive reduction of the LPS monolayer's collapse pressure, signifying that, at high concentrations, divalent salts weaken the ability of the membrane to withstand elevated stress. Finally, based on the measured viscoelastic response of the LPS films, we hypothesize that this property of LPS-rich outer membranes of bacteria permits the deformation of the membrane and may consequently protect bacteria from catastrophic structural failure when under mechanical-stress.

  19. Observations of Gas-Liquid Flows Through Contractions in Microgravity

    Science.gov (United States)

    McQuillen, John

    1996-01-01

    Tests were conducted for an air-water flow through two sudden contractions aboard the NASA DC-9 low gravity aircraft. Flow rate, residual accelerations, void fraction, film thickness, and pressure drop data were recorded and flow visualization at 250 images per second were recorded. Some preliminary results based on the flow visualization data are presented for bubbly, slug and annular flow.

  20. Langmuir and Gibbs magnetite NP layers at the air/water interface.

    Science.gov (United States)

    Stefaniu, Cristina; Chanana, Munish; Wang, Dayang; Novikov, Dmitri V; Brezesinski, Gerald; Möhwald, Helmuth

    2011-02-01

    The interfacial properties of Fe(3)O(4)@MEO(2)MA(90)-co-OEGMA(10) NPs, recently developed and described as promising nanotools for biomedical applications, have been investigated at the air/water interface. These Fe(3)O(4) NPs, capped with catechol-terminated random copolymer brushes of 2-(2-methoxyethoxy) ethyl methacrylate (MEO(2)MA) and oligo(ethylene glycol) methacrylate (OEGMA), with molar fractions of 90% and 10%, respectively, proved to be surface active. Surface tension measurements of aqueous dispersions of the NPs showed that the adsorption of the NPs at the air/water interface is time- and concentration-dependent. These NPs do not behave as classical amphiphiles. Once adsorbed at the air/water interface, they do not exchange with NPs in bulk, but they are trapped at the interface. This means that all NPs from the bulk adsorb to the interface until reaching maximum coverage of the interface, which corresponds to values between 6 × 10(-4) and 8 × 10(-4) mg/cm(2) and a critical equilibrium surface tension of ∼47 mN/m. Moreover, Langmuir layers of Fe(3)O(4)@MEO(2)MA(90)-co-OEGMA(10) NPs have been investigated by measuring surface pressure-area compression-expansion isotherms and in situ X-ray fluorescence spectra. The compression-expansion isotherms showed a plateau region above a critical surface pressure of ∼25 mN/m and a pronounced hysteresis. By using a special one-barrier Langmuir trough equipped with two surface pressure microbalances, we have shown that the NPs are squeezed out from the interface into the aqueous subphase, and they readsorb on the other side of the barrier. The results have been supported by TEM as well as AFM experiments of transferred Langmuir-Schaefer films on solid supports. This study shows the ability of Fe(3)O(4)@MEO(2)MA(90)-co-OEGMA(10) NPs to transfer from hydrophilic media (an aqueous solution) to the hydrophobic/hydrophilic interface (air/water interface) and back to the hydrophilic media. This behavior is very

  1. Ligand interaction with the purified serotonin transporter in solution and at the air/water interface

    Energy Technology Data Exchange (ETDEWEB)

    Faivre, V.; Manivet, P.; Callaway, J.C.; Morimoto, H.; Airaksinen, M.M.; Baszkin, A.; Launay, J.M.; Rosilio, V.

    2000-06-01

    The purified serotonin transporter (SERT) was spread at the air/water interface and the effects both of its surface density and of the temperature on its interfacial behavior were studied. The recorded isotherms evidenced the existence of a stable monolayer undergoing a lengthy rearrangement. SERT/ligand interactions appeared to be dependent on the nature of the studied molecules. Whereas an unrelated drug (chlorcyclizine) did not bind to the spread SERT, it interacted with its specific ligands. Compared to heterocyclic drugs, for which binding appeared to be concentration-dependent, a 'two-site' mechanism was evidenced for pinoline and imipramine.

  2. Dynamic Study of Gemini Surfactant and Single-chain Surfactant at Air/Water Interface

    Institute of Scientific and Technical Information of China (English)

    Yi Jian CHEN; Gui Ying XU; Shi Ling YUAN; Hai Ying SUN

    2005-01-01

    Molecular dynamics (MD) simulation are used to study the properties of gemini surfactant of ethyl-α,ω-bis(dodecyldimethylammonium bromide) (C12C2C12) and dodecyltrimethylammonium bromide (DTAB) at the air/water interface, respectively. In the two systems,the surfactant concentrations are both 28 wt. %, and other conditions are also the same. After reaching the thermodynamic equilibrium, the concentration profiles, the radial distributions functions (RDF) and the mean squared displacement (MSD) are investigated. Theresults reveal that the surface activity of C12C2C12 suffactant is higher than DTAB surfactant.

  3. Formation of H-type liquid crystal dimer at air-water interface

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, C., E-mail: karthik.c@pilani.bits-pilani.ac.in; Gupta, Adbhut, E-mail: karthik.c@pilani.bits-pilani.ac.in; Joshi, Aditya, E-mail: karthik.c@pilani.bits-pilani.ac.in; Manjuladevi, V., E-mail: karthik.c@pilani.bits-pilani.ac.in; Gupta, Raj Kumar, E-mail: karthik.c@pilani.bits-pilani.ac.in [Department of Physics, Birla Institute of Technology and Science, Pilani, Rajasthan -333031 (India); Varia, Mahesh C.; Kumar, Sandeep [Raman Research Institute, Sadashivanagar, Bangalore - 560080 (India)

    2014-04-24

    We have formed the Langmuir monolayer of H-shaped Azo linked liquid crystal dimer molecule at the air-water interface. Isocycles of the molecule showed hysteresis suggesting the ir-reversible nature of the monolayer formed. The thin film deposited on the silicon wafer was characterized using Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The images showed uniform domains of the dimer molecule. We propose that these molecules tend to take book shelf configuration in the liquid phase.

  4. Counter-current carbon dioxide extraction of fat from soy skim

    Science.gov (United States)

    This research aims to investigate the use of counter-current carbon dioxide extraction method as a means to reduce residual fat in soy skim after the enzyme-assisted aqueous extraction of soybeans. Extractions with liquid CO2 at 25°C and 10.34 MPa and supercritical CO2 at 50°C and 25.16 MPa are comp...

  5. Robust design of countercurrent adsorption separation processes. 4: Desorbent in the feed

    Energy Technology Data Exchange (ETDEWEB)

    Mazzotti, M. [Politecnico di Milano (Italy). Dipt. di Chimica; Storti, G. [Univ. degli Studi di Cagliari (Italy). Dipt. di Ingegneria Chimica e Materiali; Morbidelli, M. [ETH Zentrum, Zuerich (Switzerland). Lab. fuer Technische Chemie

    1997-01-01

    In many instances of practical interest, countercurrent adsorption separations operate on feed streams containing not only the components to be separated but also some desorbent. Criteria for the optimal and robust design and operation of these units are developed by extending previous treatments developed for desorbent-free feedstreams. The effect of the presence of some desorbent (weak, intermediate, or strong) on the location and robustness of the region of complete separation in the operating parameter space is discussed.

  6. Selective isolation of components from natural volatile oil by countercurrent chromatography with cyclodextrins as selective reagent.

    Science.gov (United States)

    Tong, Shengqiang; Lu, Mengxia; Chu, Chu; Yan, Jizhong; Huang, Juan; Ying, Yongfei

    2016-04-29

    Selective separation of chemical components from seven kinds of volatile oil by countercurrent chromatography with three types of cyclodextrins as selective reagent was investigated in this work. Preparative separation of chemical components from volatile oil is generally quite challenging due to their extremely complexity of the composition. A biphasic solvent system n-hexane-0.10 mol L(-1) cyclodextrin (1:1, v/v) was selected for separation of components from volatile oil and three types of cyclodextrins were investigated, including β-cyclodexrin, methyl-β-cyclodexrin and hydroxypropyl-β-cyclodexrin. All kinds of volatile oils are from seven kinds of traditional Chinese herb. Results showed that some chemical components could be well separated with high purity from each kind of volatile oil using different type of cyclodextrin as selective reagent. For example, germacrone and curcumenone could be selectively separated from volatile oil of Curcumae Rhizoma with methyl-β-cyclodexrin and hydroxypropyl-β-cyclodexrin as selector respectively, and other five components were selectively separated from volatile oil of Chuanxiong Rhizoma, Myristicae Semen, Aucklandiae Radix and Angelicae Sinensis Radix by countercurrent chromatography with different cyclodexrin as selective reagent. Separation mechanism for separation of components from volatile oil by countercurrent chromatography with cyclodextrin as selective reagent was proposed. Peak resolution of the present separation method could be greatly influenced by the chemical compositions of volatile oil.

  7. Modelling of cross-flow membrane contactors : Physical mass transfer processes

    NARCIS (Netherlands)

    Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.

    2005-01-01

    Traditionally, hollow fiber membrane contactors used for gas-liquid contacting were designed in a shell and tube configuration with shell-side fluid flowing parallel to the fiber-side fluid, either in co-current or counter-current pattern. The primary limitations of these so-called 'parallel flow' c

  8. Surface properties and morphology of mixed POSS-DPPC monolayers at the air/water interface.

    Science.gov (United States)

    Rojewska, Monika; Skrzypiec, Marta; Prochaska, Krystyna

    2017-02-01

    From the point of view of the possible medical applications of POSS (polyhedral oligomeric silsesquioxanes), it is crucial to analyse interactions occurring between POSS and model biological membrane at molecular level. Knowledge of the interaction between POSS and DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) allows prediction of the impact of POSS contained in biomaterials or cosmetics on a living organism. In the study presented, the surface properties and morphology of Langmuir monolayers formed by mixtures of POSS and the phospholipid (DPPC) at the air/water surface are examined. We selected two POSS derivatives, with completely different chemical structure of substituents attached to the corner of the silicon open cage, which allowed the analysis of the impact of the character of organic moieties (strongly hydrophobic or clearly hydrophilic) on the order of POSS molecules and their tendency to form self-aggregates at the air/water surface. POSS derivatives significantly changed the profile of the π-A isotherms obtained for DPPC but in different ways. On the basis of the regular solution theory, the miscibility and stability of the two components in the monolayer were analysed in terms of compression modulus (Cs(-1)), excess Gibbs free energy (ΔGexc), activity coefficients (γ) and interaction parameter (ξ). The results obtained indicate the existence of two different interaction mechanisms between DPPC and POSS which depend on the chemical character of moieties present in POSS molecules.

  9. Research on measurement-device-independent quantum key distribution based on an air-water channel

    Science.gov (United States)

    Zhou, Yuan-yuan; Zhou, Xue-jun; Xu, Hua-bin; Cheng, Kang

    2016-11-01

    A measurement-device-independent quantum key distribution (MDI-QKD) method with an air-water channel is researched. In this method, the underwater vehicle and satellite are the legitimate parties, and the third party is at the airwater interface in order to simplify the unilateral quantum channel to water or air. Considering the condition that both unilateral transmission distance and transmission loss coefficient are unequal, a perfect model of the asymmetric channel is built. The influence of asymmetric channel on system loss tolerance and secure transmission distance is analyzed. The simulation results show that with the increase of the channel's asymmetric degree, the system loss tolerance will descend, one transmission distance will be reduced while the other will be increased. When the asymmetric coefficient of channel is between 0.068 and 0.171, MDI-QKD can satisfy the demand of QKD with an air-water channel, namely the underwater transmission distance and atmospheric transmission distance are not less than 60 m and 12 km, respectively.

  10. Air-water gas exchange and CO2 flux in a mangrove-dominated estuary

    Science.gov (United States)

    Ho, David T.; Ferrón, Sara; Engel, Victor C.; Larsen, Laurel G.; Barr, Jordan G.

    2014-01-01

    Mangrove forests are highly productive ecosystems, but the fate of mangrove-derived carbon remains uncertain. Part of that uncertainty stems from the fact that gas transfer velocities in mangrove-surrounded waters are not well determined, leading to uncertainty in air-water CO2 fluxes. Two SF6 tracer release experiments were conducted to determine gas transfer velocities (k(600) = 8.3 ± 0.4 and 8.1 ± 0.6 cm h−1), along with simultaneous measurements of pCO2 to determine the air-water CO2 fluxes from Shark River, Florida (232.11 ± 23.69 and 171.13 ± 20.28 mmol C m−2 d−1), an estuary within the largest contiguous mangrove forest in North America. The gas transfer velocity results are consistent with turbulent kinetic energy dissipation measurements, indicating a higher rate of turbulence and gas exchange than predicted by commonly used wind speed/gas exchange parameterizations. The results have important implications for carbon fluxes in mangrove ecosystems.

  11. Predicting Air-Water Geysers and Their Implications on Reducing Combined Sewer Overflows

    Science.gov (United States)

    Choi, Y.; Leon, A.; Apte, S.

    2014-12-01

    An air-water geyser in a closed conduit system is characterized by an explosive jetting of a mixture of air and water through drop-shafts. In this study, three scenarios of geysers are numerically simulated using a 3D computational fluid dynamics (CFD) model. The three tested scenarios are comprised of a drop shaft that is closed at its bottom and partially or fully open at the top. Initially, the lower section of the drop shaft is filled with pressurized air, the middle section with stagnant water and the upper section with air at atmospheric pressure. The pressure and volume of the pressurized air, and hence the stored energy, is different for all three test cases. The volume of the stagnant water and the air at atmospheric pressure are kept constant in the tests. The numerical simulations aim to identify the correlation between dimensionless energy stored in the pressurized air pocket and dimensionless maximum pressure reached at the outlet. This dimensionless correlation could be used to determine the energy threshold that does not produce air-water geyser, which in turn could be used in the design of combined sewer systems for minimizing geysers.

  12. Evaporative assembly of MEH-PPV rings using mixed solvents at the air/water interface.

    Science.gov (United States)

    Chao, Kung-Po; Biswal, Sibani L

    2014-04-22

    Controlling the morphology of conjugated polymers has recently attracted considerable attention because of their applications in photovoltaic (PV) devices and organic light-emitting diodes (OLEDs). Here, we describe the self-assembly of a common conjugated polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), into ringlike structures via solvent evaporation on an air/water interface. The films are monitored using Brewster angle microscopy (BAM) and transferred onto a solid substrate by either the Langmuir-Blodgett (LB) or the Langmuir-Schaefer (LS) method and further characterized by atomic force microscopy (AFM). The morphology of the MEH-PPV thin film at the air/water interface can be controlled by the spreading solvent. By mixing solvents of varying spreading coefficients and evaporation rates, such as chloroform and chlorobenzene, MEH-PPV can be assembled into micrometer-sized ring structures. The optical properties of these MEH-PPV ring structures are also characterized. Lastly, MEH-PPV can be used as a soft template to organize microscale structures of nanoparticles.

  13. Dipole Moment of a Charged Particle Trapped at the Air-Water Interface.

    Science.gov (United States)

    Bossa, Guilherme Volpe; Bohinc, Klemen; Brown, Matthew A; May, Sylvio

    2016-07-07

    The interaction between two charged particles (such as nanoparticles or colloids) trapped at the air-water interface becomes dipolar at large separations. The corresponding dipole moment can be modeled by considering a single point charge located exactly at the interface, but this model fails to correctly predict the dipole moment's dependence on the salt concentration in the aqueous medium. We extend the single point charge model to two point charges that are separated by a fixed distance and are located at the air-water interface, with one charge being immersed in air and the other in the solvent. The two point charges represent the surface charges at the air-exposed and water-exposed regions of an interface-trapped particle. The two point charges also account for the spatial extension of the particle. On the basis of the Debye-Hückel model, we derive mathematical expressions for the interaction between two pairs of charges and discuss the salt concentration dependence of the dipolar moment at large separations. Our results reveal a residual dipole moment in the limit of large salt content that originates from the charge attached to the air-exposed region of the particle. We discuss nonlinear screening effects and compare the predicted dipolar moments with recent experimental results.

  14. Bovine insulin-phosphatidylcholine mixed Langmuir monolayers: behavior at the air-water interface.

    Science.gov (United States)

    Pérez-López, S; Blanco-Vila, N M; Vila-Romeu, N

    2011-08-04

    The behavior of the binary mixed Langmuir monolayers of bovine insulin (INS) and phosphatidylcholine (PC) spread at the air-water interface was investigated under various subphase conditions. Pure and mixed monolayers were spread on water, on NaOH and phosphate-buffered solutions of pH 7.4, and on Zn(2+)-containing solutions. Miscibility and interactions between the components were studied on the basis of the analysis of the surface pressure (π)-mean molecular area (A) isotherms, surface compression modulus (C(s)(-1))-π curves, and plots of A versus mole fraction of INS (X(INS)). Our results indicate that intermolecular interactions between INS and PC depend on both the monolayer state and the structural characteristics of INS at the interface, which are strongly influenced by the subphase pH and salt content. Brewster angle microscopy (BAM) was applied to investigate the peptide aggregation pattern at the air-water interface in the presence of the studied lipid under any experimental condition investigated. The influence of the lipid on the INS behavior at the interface strongly depends on the subphase conditions.

  15. Biogenic amine – surfactant interactions at the air-water interface.

    Science.gov (United States)

    Penfold, J; Thomas, R K; Li, P X

    2015-07-01

    The strong interaction between polyamines and anionic surfactants results in pronounced adsorption at the air-water interface and can lead to the formation of layered surface structures. The transition from monolayer adsorption to more complex surface structures depends upon solution pH, and the structure and molecular weight of the polyamine. The effects of manipulating the polyamine molecular weight and structure on the adsorption of the anionic surfactant sodium dodecyl sulphate at the air-water interface are investigated using neutron reflectivity and surface tension, for the biogenic amines putrescine, spermidine and spermine. The results show how changing the number of amine groups and the spacing between the amine groups impacts upon the surface adsorption. At lower pH, 3-7, and for the higher molecular weight polyamines, spermidine and spermine, ordered multilayer structures are observed. For putrescine at all pH and for spermidine and spermine at high pH, monolayer adsorption with enhanced surfactant adsorption compared to the pure surfactant is observed. The data for the biogenic amines, when compared with similar data for the polyamines ethylenediamine, diethylenetriamine and triethylenetetramine, indicate that the spacing between amines groups is more optimal for the formation of ordered surface multilayer structures.

  16. Isolation of dimeric, trimeric, tetrameric and pentameric procyanidins from unroasted cocoa beans (Theobroma cacao L.) using countercurrent chromatography.

    Science.gov (United States)

    Esatbeyoglu, Tuba; Wray, Victor; Winterhalter, Peter

    2015-07-15

    The main procyanidins, including dimeric B2 and B5, trimeric C1, tetrameric and pentameric procyanidins, were isolated from unroasted cocoa beans (Theobroma cacao L.) using various techniques of countercurrent chromatography, such as high-speed countercurrent chromatography (HSCCC), low-speed rotary countercurrent chromatography (LSRCCC) and spiral-coil LSRCCC. Furthermore, dimeric procyanidins B1 and B7, which are not present naturally in the analysed cocoa beans, were obtained after semisynthesis of cocoa bean polymers with (+)-catechin as nucleophile and separated by countercurrent chromatography. In this way, the isolation of dimeric procyanidin B1 in considerable amounts (500mg, purity>97%) was possible in a single run. This is the first report concerning the isolation and semisynthesis of dimeric to pentameric procyanidins from T. cacao by countercurrent chromatography. Additionally, the chemical structures of tetrameric (cinnamtannin A2) and pentameric procyanidins (cinnamtannin A3) were elucidated on the basis of (1)H NMR spectroscopy. Interflavanoid linkage was determined by NOE-correlations, for the first time.

  17. Separation and purification of two new and two known alkaloids from leaves of Nitraria sibirica by pH-zone-refining counter-current chromatography.

    Science.gov (United States)

    Bakri, Mahinur; Chen, Qibin; Ma, Qingling; Yang, Yi; Abdukadir, Abdumijit; Aisa, Haji Akber

    2015-12-01

    The total alkaloids from Nitraria sibirica leaves have been confirmed to exhibit significant protective effects against inflammatory renal injury, hypertension and albuminuria in angiotensin II-salt hypertension. In the present study, a separation method of pH-zone-refining counter-current chromatography was established for separation of the alkaloids from N. sibirica. The separation was performed with a solvent system of MtBE-n-BuOH-H2O (2:2:5, v/v) at a flow rate of 2.0mL/min. And 15mM triethylamine (TEA) was added to the upper organic phase, while 10mM hydrochloric acid was added to the lower aqueous phase. As a result, a new alkaloid, schobemine (5.6mg), and a known alkaloid, nitraramine (5.0mg), together with fractions A and B were obtained from the total alkaloids of N. sibirica. The fractions A and B were further purified by means of pH-zone-refining counter-current chromatography with solvent systems of n-hexane-n-BuOH-H2O (1.5:3.5:5, v/v) and (2:3:5, v/v), respectively. TEA (10mM) was added to the upper phase, and 10mM of HCl was added to the lower phase in above two solvent systems, respectively. As a result, a known alkaloid, schoberidine (5.0mg), and a new alkaloid, schoberimine (3.0mg) were obtained from fractions A and B, respectively. The purities of the compounds were measured by HPLC-ELSD, and their structures were identified by ESI-MS, 1D and 2D NMR.

  18. SOME CHARACTERISTICS OF LOW-SPEED STREAKS UNDER SHEARED AIR-WATER INTERFACES

    Institute of Scientific and Technical Information of China (English)

    王双峰; 贾复

    2001-01-01

    The characteristics of low-speed fluid streaks occurring under sheared air-water interfaces were examined by means of hydrogen bubble visualization tech nique. A critical shear condition under which the streaky structure first appears was determined to be uT ≈ 0.19 cm/s. The mean spanwise streak spacing increases with distance from the water surface owing to merging and bursting processes, and a lin ear relationship describing variation of non-dimensional spacing λ+- versus y+ was found essentially independent of shear stress on the interface. Values ofλ+, however,are remarkably smaller than their counterparts in the near-wall region of turbulent boundary layers. Though low-speed streaks occur randomly in time and space, the streak spacing exhibits a lognormal probability distribution behavior. A tentative explanation concerning the formation of streaky structure is suggested, and the fact that λ+ takes rather smaller values than that in wall turbulence is briefly discussed.

  19. Mercury Exchange at the Air-Water-Soil Interface: An Overview of Methods

    Directory of Open Access Journals (Sweden)

    Fengman Fang

    2002-01-01

    Full Text Available An attempt is made to assess the present knowledge about the methods of determining mercury (Hg exchange at the air-water-soil interface during the past 20 years. Methods determining processes of wet and dry removal/deposition of atmospheric Hg to aquatic and terrestrial ecosystems, as well as methods determining Hg emission fluxes to the atmosphere from natural surfaces (soil and water are discussed. On the basis of the impressive advances that have been made in the areas relating to Hg exchange among air-soil-water interfaces, we analyzed existing problems and shortcomings in our current knowledge. In addition, some important fields worth further research are discussed and proposed.

  20. Partitioning of semi-volatile organic compounds to the air/water interface

    Science.gov (United States)

    Pankow, James F.

    Partition coefficients ( Kia, m 3m -2) for sorption of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes at the air/water interface were estimated by extrapolating quartz/gas sorption data to relative humidity (RH) values of 100%. For each compound class, the log Kia values were found to be well correlated with log pLo where pLo (Torr) is the vapor pressure of the pure subcooled liquid. For the PAHs, correlation equation is log Kia = -1.20 log pLo - 5.82 ( R2 = 0.98). For the n-alkanes, the correlation equation is log Kia = -0.93 log pLo - 4.42 ( R2 = 0.95).

  1. Crystalline mono- and multilayer self-assemblies of oligothiophenes at the air-water interface

    DEFF Research Database (Denmark)

    Isz, S.; Weissbuch, I.; Kjær, K.;

    1997-01-01

    of aromatic nonamphiphilic molecules, self-aggregated at the air-water interface. As model systems we have examined the deposition of quaterthiophene (S-4), quinquethiophene (S-5). and sexithiophene (S-6) from chloroform solutions on the water surface. The structures of the films were determined by surface...... pressure-area isotherms, by scanning force microscopy (SFM) after transfer of the films onto atomically smooth mica, by cryo-transmission electron microscopy (Cryo-TEM) on vitreous ice, and by grazing incidence synchrotron X-ray diffraction (GID) directly on the water surface. S-4 forms two polymorphic...... surface. S-5 self-ageregates at the water surface to form mixtures of monolayers and bilayers of the beta polymorph; S-6 forms primarily crystalline monolayers of both alpha and beta forms. The crystalline assemblies preserve their integrity during transfer from the water surface onto solid supports...

  2. Slow dynamics of phospholipid monolayers at the air/water interface

    CERN Document Server

    Choi, Siyoung Q

    2009-01-01

    Phospholipid monolayers at the air-water interface serve as model systems for various biological interfaces, e.g. lung surfactant layers and outer leaflets of cell membranes. Although the dynamical (viscoelastic) properties of these interfaces may play a key role in stability, dynamics and function, the relatively weak rheological properties of most such monolayers have rendered their study difficult or impossible. A novel technique to measure the dynamical properties of fluid-fluid interfaces have developed accordingly. We microfabricate micron-scale ferromagnetic disks, place them on fluid-fluid interfaces, and use external electromagnets to exert torques upon them. By measuring the rotation that results from a known external torque, we compute the rotational drag, from which we deduce the rheological properties of the interface. Notably, our apparatus enable direct interfacial visualization while the probes are torqued. In this fluid dynamics video, we directly visualize dipalmitoylphosphatidylcholine(DPPC...

  3. Two-dimensional Insect Flight on an Air-Water Interface is a Chaotic Oscillator

    CERN Document Server

    Mukundarajan, Haripriya; Prakash, Manu

    2014-01-01

    Two-dimensional flapping wing insect flight on an air-water interface provides a successful foraging strategy to explore an ecological niche on the surface of a pond. However, the complex interplay of surface tension, aerodynamic forces, biomechanics and neural control that enables two-dimensional flight is unknown. Here we report the discovery of two-dimensional flight in the waterlily beetle Galerucella nymphaeae, which is the fastest reported propulsion mode for an insect on a fluid interface. Using kinematics derived from high-speed videography coupled with analytical models, we demonstrate that two-dimensional flight is a chaotic interfacial oscillator, thus significantly constraining the possible range of flight parameters. Discovery of this complex dynamics in two-dimensional flight on time scales similar to neural responses indicates the challenge of evolving active flight control on a fluid interface.

  4. Anomalous spreading behaviour of polyethyleneglycoldistearate monolayers at air/water interface

    Indian Academy of Sciences (India)

    S John Collins; Aruna Dhathathreyan; T Ramasami

    2001-04-01

    Spreading behaviour of the dimeric surfactant polyethyleneglycoldistearate (PEGDS) monolayer at air/water interface has been studied using surface pressure-area ( -) isotherms as a function of temperature. The isotherms show a plateau suggesting a transition between a liquid expanded (LE) and a condensed state. The condensed state possibly arises due to nucleation and growth of multilayers from the monolayer. Isobaric measurements of both - and - at constant area show transitions at = 295 K. These plots suggest a melting followed by formation of condensed microcrystallites. Structure optimization carried out using various angles of orientation of the alkyl tails with respect to the backbone in PEGDS reveals tilt transitions of the tails in different states which can be related to the packing behaviour seen in the isotherms. Optical microscopy has been used to confirm the structures in these states.

  5. Atmospheric photochemistry at a fatty acid-coated air-water interface

    Science.gov (United States)

    Rossignol, Stéphanie; Tinel, Liselotte; Bianco, Angelica; Passananti, Monica; Brigante, Marcello; Donaldson, D. James; George, Christian

    2016-08-01

    Although fatty acids are believed to be photochemically inert in the actinic region, complex volatile organic compounds are produced during illumination of an air-water interface coated solely with a monolayer of carboxylic acid. When aqueous solutions containing nonanoic acid (NA) at bulk concentrations that give rise to just over a monolayer of NA coverage are illuminated with actinic radiation, saturated and unsaturated aldehydes are seen in the gas phase, and more highly oxygenated products appear in the aqueous phase. This chemistry is probably initiated by triplet-state NA molecules excited by direct absorption of actinic light at the water surface. Because fatty acids-covered interfaces are ubiquitous in the environment, such photochemical processing will have a substantial impact on local ozone and particle formation.

  6. Turbulent heat and mass transfers across a thermally stratified air-water interface

    Science.gov (United States)

    Papadimitrakis, Y. A.; Hsu, Y.-H. L.; Wu, J.

    1986-01-01

    Rates of heat and mass transfer across an air-water interface were measured in a wind-wave research facility, under various wind and thermal stability conditions (unless otherwise noted, mass refers to water vapor). Heat fluxes were obtained from both the eddy correlation and the profile method, under unstable, neutral, and stable conditions. Mass fluxes were obtained only under unstable stratification from the profile and global method. Under unstable conditions the turbulent Prandtl and Schmidt numbers remain fairly constant and equal to 0.74, whereas the rate of mass transfer varies linearly with bulk Richardson number. Under stable conditions the turbulent Prandtl number rises steadily to a value of 1.4 for a bulk Richardson number of about 0.016. Results of heat and mass transfer, expressed in the form of bulk aerodynamic coefficients with friction velocity as a parameter, are also compared with field data.

  7. The effect of bubbles on air-water oxygen transfer in the breaker zone

    Science.gov (United States)

    Kakuno, Shohachi; Moog, Douglas B.; Tatekawa, Tetsuya; Takemura, Kenji; Yamagishi, Tatsuya

    The effect of bubbles entrained in the breaker zone on air-water oxygen transfer is examined. First, the area of bubbles entrained by breakers generated on a sloping bottom in a wave tank is analyzed using a color image sensor which can count the pixel number of a specific color in a frame. It was found that the time-averaged pixel number over a wave period has a strong relationship to the energy dissipation rate per unit mass of the breaker. The time-averaged pixel number is then incorporated with some modification into an equation proposed by Eckenfelder for the calculation of the mass transfer coefficient from bubble surfaces in an aeration tank. The coefficient resulting from the modified equation shows a strong relationship between the mass transfer coefficient and the dissipation rate.

  8. A Comparative Cycle and Refrigerant Simulation Procedure Applied on Air-Water Heat Pumps

    DEFF Research Database (Denmark)

    Mader, Gunda; Palm, Björn; Elmegaard, Brian

    2012-01-01

    A vapor compression heat pump absorbs heat from the environment at a low temperature level and rejects heat at a high temperature level. The bigger the difference between the two temperature levels the more challenging is it to gain high energy efficiency with a basic cycle layout as found in most...... small capacity heat pump applications today. Many of the applicable refrigerants also reach their technical limits regarding low vapor pressure for very low source temperatures and high discharge temperatures for high sink temperatures. These issues are especially manifest for air-water heat pumps. Many...... alternative cycle setups and refrigerants are known to improve the energy efficiency of a vapor compression cycle and reduce discharge temperatures. However not all of them are feasible for small capacity heat pumps from a cost and complexity point of view. This paper presents a novel numerical approach...

  9. Crystalline self-assembly into monolayers of folded oligomers at the air-water interface

    DEFF Research Database (Denmark)

    Lederer, K.; Godt, A.; Howes, P.B.;

    2000-01-01

    of the folding unit almost perpendicular to the water surface, as determined by synchrotron grazing-incidence X-ray diffraction. Three distinct molecular shapes, of the types U, inverted U, and M, were obtained in the two-dimensional crystalline state, depending upon the number of spacer units, and the number......Insertion of the 115-bis(ethynylene)benzene unit as a rigid spacer into a linear alkyl chain, thus separating the two resulting stems by 9 Angstrom, induces chain folding at the air-water interface. These folded molecules self-assemble into crystalline monolayers at this interface, with the plane...... and position of the hydrophilic groups in the molecule. The molecules form ribbons with a higher crystal coherence in the direction of stacking between the molecular ribbons, and a lower coherence along the ribbon direction. A similar molecule, but with a spacer unit that imposes a 5 Angstrom separation...

  10. Is countercurrent regeneration an option for condensate polishing? Yes, it is.

    Energy Technology Data Exchange (ETDEWEB)

    Daucik, K. [DONG Energy Generation A/S, Fredericia (Denmark)

    2008-03-15

    This paper presents a brief report on operation experience with a three-train separate bed condensate polisher in countercurrent operation/regeneration mode installed at a 400 MW ultra supercritical unit. Operation data show that the quality of the polished condensate is superior to that of the previously used standard (cation-mixed bed) condensate polisher, and it has been possible to almost completely eliminate sodium sulfate-related deposition problems in the plant cycle experienced when operating with that standard design unit. (orig.)

  11. Use of two-stage membrane countercurrent cascade for natural gas purification from carbon dioxide

    Science.gov (United States)

    Kurchatov, I. M.; Laguntsov, N. I.; Karaseva, M. D.

    2016-09-01

    Membrane technology scheme is offered and presented as a two-stage countercurrent recirculating cascade, in order to solve the problem of natural gas dehydration and purification from CO2. The first stage is a single divider, and the second stage is a recirculating two-module divider. This scheme allows natural gas to be cleaned from impurities, with any desired degree of methane extraction. In this paper, the optimal values of the basic parameters of the selected technological scheme are determined. An estimation of energy efficiency was carried out, taking into account the energy consumption of interstage compressor and methane losses in energy units.

  12. High-speed counter-current chromatographic isolation of ricinine, an insecticide from Ricinus communis.

    Science.gov (United States)

    Cazal, Cristiane de Melo; Batalhão, Jaqueline Raquel; Domingues, Vanessa de Cássia; Bueno, Odair Corrêa; Filho, Edson Rodrigues; Forim, Moacir R; da Silva, Maria Fátima G Fernandes; Vieira, Paulo Cezar; Fernandes, João Batista

    2009-05-08

    The alkaloid ricinine, an insecticide for leaf-cutting ant (Atta sexdens rubropilosa), was obtained from Ricinus communis. A two-phase solvent system composed of CH(2)Cl(2)/EtOH/H(2)O (93:35:72, v/v/v) was used for high-speed counter-current chromatographic (HSCCC) isolation of ricinine in high yield and with over 96% purity, as determined by liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS). Identification of ricinine was performed by comparison of (1)H NMR, (13)C NMR and LC-MS/MS data.

  13. Protein Exposed Hydrophobicity Reduces the Kinetic Barrier for Adsorption of Ovalbumin to the Air-Water Interface

    NARCIS (Netherlands)

    Wierenga, P.A.; Meinders, M.B.J.; Egmond, M.R.; Voragen, F.A.G.J.; Jongh, H.H.J. de

    2003-01-01

    Using native and caprylated ovalbumin, the role of exposed hydrophobicity on the kinetics of protein adsorption to the air - water interface is studied. First, changes in the chemical properties of the protein upon caprylation were characterized followed by measurement of the changes in adsorption k

  14. Protein exposed hydrophobicity reduces the kinetic barrier for adsoption of ovalbumin to the air-water interface.

    NARCIS (Netherlands)

    Wierenga, P.A.; Meinders, M.B.J.; Egmond, M.R.; Voragen, A.G.J.

    2003-01-01

    Using native and caprylated ovalbumin, the role of exposed hydrophobicity on the kinetics of protein adsorption to the air-water interface is studied. First, changes in the chemical properties of the protein upon caprylation were characterized followed by measurement of the changes in adsorption kin

  15. Comparison of the dilational behaviour of adsorbed milk proteins at the air-water and oil-water interfaces.

    NARCIS (Netherlands)

    Williams, A.; Prins, A.

    1996-01-01

    The interfacial dilational properties of two milk proteins, β-casein and β-lactoglobulin, have been compared at the air-water and paraffin oil-water interfaces. The measurements were performed as a function of bulk protein concentration using a modified Langmuir trough technique at a frequency of 0.

  16. Stress-strain curves of adsorbed protein layers at the air/water interface measured with surface shear rheology

    NARCIS (Netherlands)

    Martin, A.; Bos, M.; Stuart, M.C.; Vliet, T. van

    2002-01-01

    Interfacial shear properties of adsorbed protein layers at the air/water interface were determined using a Couette-type surface shear rheometer. Such experiments are often used to determine a steady-state ratio between stress and rate of strain, which is then denoted as "surface shear viscosity". Ho

  17. Conformational aspects of proteins at the air/water interface studied by infrared reflection-absorption spectroscopy

    NARCIS (Netherlands)

    Martin, A.H.; Meinders, M.B.J.; Bos, M.A.; Cohen Stuart, M.A.; Vliet, T. van

    2003-01-01

    From absorption spectra obtained with infrared reflection - absorption spectroscopy (IRRAS), it is possible to obtain information on conformational changes at a secondary folding level of proteins adsorbed at the air/water interface. In addition, information on protein concentration at the interface

  18. Chiral Discrimination in N-(O, O-dialkyl)phosphoamino Acid Monolayers at the Air-water Interface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, chiral discrimination in N-(O,O-dialkyl)phosphoamino acid monolayers at the air/water interface was studied and it was revealed that the D:L=1:1 racemic monolayer of N-(O, O-dihexadecyl)phosphoalanine is packed more densely in solid phase while shows a higher LE to LC transition pressure than the enantiomeric ones.

  19. Improving Efficiency of a Counter-Current Flow Moving Bed Granular Filter

    Energy Technology Data Exchange (ETDEWEB)

    Colver, G.M.; Brown, R.C.; Shi, H.; Soo, D.S-C.

    2002-09-18

    The goal of this research is to improve the performance of moving bed granular filters for gas cleaning at high temperatures and pressures. A second goal of the research is to optimize the performances of both solids and gas filtering processes through appropriate use of granular bed materials, particle sizes, feed rates etc. in a factorial study. These goals are directed toward applications of advanced coal-fired power cycles under development by the U.S. Department of Energy including pressurized fluidized bed combustion and integrated gasification/combined cycles based on gas turbines and fuel cells. Only results for particulate gas cleaning are reported here.

  20. Enrichment and separation of antitumor triterpene acids from the epidermis of Poria cocos by pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography.

    Science.gov (United States)

    Dong, Hongjing; Wu, Panpan; Yan, Renyi; Xu, Qihua; Li, Hua; Zhang, Fangbo; Li, Jianrong; Yang, Bin

    2015-06-01

    Triterpene acids were extracted from the epidermis of Poria cocos (Schw.) Wolf. These acids were found to inhibit the growth of lung cancer cells in vitro and in vivo. An efficient method for the preparative separation of antitumor triterpene acids was established that involves the combination of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography. We used pH-zone-refining counter-current chromatography to concentrate the triterpene acids using a two-phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (3:7:5:5, v/v/v/v), trifluoroacetic acid (10 mM) was added to the upper phase as a retainer, and ammonia (10 mM) was added to the lower phase as an eluter. As a result, 200 mg concentrate of triterpene acids was obtained from 1.0 g of crude extract. The concentrate was further separated by conventional high-speed counter-current chromatography using a solvent system composed of petroleum ether/ethyl acetate/methanol/water (0.8:1.2:1.2:0.9, v/v), yielding 50 mg of poricoic acid A and 5 mg of poricoic acid B from 120 mg concentrate, respectively. The inhibitory activity of the major compound on lung A549 cells was examined and poricoic acid A was found to significantly inhibit the growth of A 549 cells.

  1. Low sensitivity of counter-current immuno-electrophoresis for serodiagnosis of typhoid fever.

    Science.gov (United States)

    Sharma, M; Datta, U; Roy, P; Verma, S; Sehgal, S

    1997-12-01

    Counter-current immuno-electrophoresis was evaluated as a diagnostic test for the serodiagnosis of typhoid fever with somatic (O), flagellar (H) and capsular polysaccharide (Vi) antigens of Salmonella typhi on the sera of patients who were blood culture positive (confirmed typhoid cases) or had high Widal agglutination titres, > or = 320, (presumptive typhoid cases). Of the 37 sera from confirmed cases, 30% showed positivity with O antigen, 24% with H antigens and 51% with Vi antigen. In patients with a presumptive diagnosis, 45% were positive for O antibody, 27% for flagellar antibody and 52% for Vi antibody. When all three antigens were combined the reactivity to any of the antigens was found to be 59% in confirmed typhoid cases, 79% in presumptive typhoid cases and 93% in patients who were simultaneously positive by blood culture and Widal agglutination. However, none of the sera from 45 controls gave a positive precipitation reaction with any of the antigens. It is concluded that counter-current immuno-electrophoresis is a rapid test with low sensitivity and high specificity with Vi antigen, a panel of antigens being most effective, and is, therefore, recommended for rapid diagnosis of typhoid fever.

  2. Reverse osmosis concentrate treatment via a PAC-MF accumulative countercurrent adsorption process.

    Science.gov (United States)

    Zhao, Chunxia; Gu, Ping; Cui, Hangyu; Zhang, Guanghui

    2012-01-01

    Organic pollutants in reverse osmosis (RO) concentrates from wastewater reclamation are mainly comprised of low molecular weight biorefractory compounds. Generally, advanced oxidation methods for oxidizing these organics require a relatively high level of energy consumption. In addition, conventional adsorption removal methods require a large dose of activated carbon. However, the dose can be reduced if its full adsorption capacity can be used. Therefore, the combined technology of powdered activated carbon (PAC) adsorption and microfiltration (MF) membrane filtration was studied to develop a countercurrent two-stage adsorption process. A PAC accumulative adsorption prediction method was proposed based on the verification of a PAC multi-stage adsorption capacity equation. Moreover, the prediction method was amended for a more accurate prediction of the effluent quality because adsorption isotherm constants were affected by the initial adsorbate concentration. The required PAC dose for the accumulative countercurrent two-stage adsorption system was 0.6 g/L, whereas that of the conventional adsorption process was 1.05 g/L when the dilution factor(F) was 0.1 and the COD and DOC removal rates were set to 70% and 68.1%, respectively. Organic pollutants were satisfactorily removed with less consumption of PAC. Effluent from this combined technology can be further reclaimed by an RO process to improve the overall recovery rate to between 91.0% and 93.8% with both economic and environmental benefits.

  3. Studies on the performance of different coiled column configurations for compact type-I countercurrent chromatography.

    Science.gov (United States)

    Yang, Yi; Gu, Dongyu; Aisa, Haji Akber; Ito, Yoichiro

    2011-05-01

    Three types of novel coiled column configurations, i.e. a triangular coiled column and elliptical coiled columns I and II, were designed for type-I countercurrent chromatography and their performances were evaluated with two solvent systems each with suitable test samples. Three dinitrophenyl (DNP) amino acids (DNP-DL-glu, DNP-β-ala and DNP-L-ala) were separated with a moderately hydrophobic two-phase solvent system composed of hexane-ethyl acetate-metanol-0.1 M hydrochloric acid (1:1:1:1, v/v), while two dipeptides (tryptophyl-tyrosine and valyl-tyrosine) were separated with a polar solvent system composed of 1-butanol-acetic acid-water (4.75:0.25:5, v/v). The overall results indicated that the performance of compact type-I countercurrent chromatography was improved by elliptical coiled column I which was mounted with its maximum coil diameter perpendicular to the surface of the column holder. Hydrodynamic effects involved in these separations were discussed.

  4. Purification of semiconducting single-walled carbon nanotubes by spiral counter-current chromatography.

    Science.gov (United States)

    Knight, Martha; Lazo-Portugal, Rodrigo; Ahn, Saeyoung Nate; Stefansson, Steingrimur

    2017-02-03

    Over the last decade man-made carbon nanostructures have shown great promise in electronic applications, but they are produced as very heterogeneous mixtures with different properties so the achievement of a significant commercial application has been elusive. The dimensions of single-wall carbon nanotubes are generally a nanometer wide, up to hundreds of microns long and the carbon nanotubes have anisotropic structures. They are processed to have shorter lengths but they need to be sorted by diameter and chirality. Thus counter-current chromatography methods developed for large molecules are applied to separate these compounds. A modified mixer-settler spiral CCC rotor made with 3 D printed disks was used with a polyethylene glycol-dextran 2-phase solvent system and a surfactant gradient to purify the major species in a commercial preparation. We isolated the semi-conducting single walled carbon nanotube chiral species identified by UV spectral analysis. The further development of spiral counter-current chromatography instrumentation and methods will enable the scalable purification of carbon nanotubes useful for the next generation electronics.

  5. Separation and purification of five alkaloids from Aconitum duclouxii by counter-current chromatography.

    Science.gov (United States)

    Wang, Yarong; Cai, Shining; Chen, Yang; Deng, Liang; Zhou, Xumei; Liu, Jia; Xu, Xin; Xia, Qiang; Lin, Mao; Zhang, Jili; Huang, Weili; Wang, Wenjun; Xiang, Canhui; Cui, Guozhen; Du, Lianfeng; He, Huan; Qi, Baohui

    2015-07-01

    C19 -diterpenoid alkaloids are the main components of Aconitum duclouxii Levl. The process of separation and purification of these compounds in previous studies was tedious and time consuming, requiring multiple chromatographic steps, thus resulted in low recovery and high cost. In the present work, five C19 -diterpenoid alkaloids, namely, benzoylaconine (1), N-deethylaconitine (2), aconitine (3), deoxyaconitine (4), and ducloudine A (5), were efficiently prepared from A. duclouxii Levl (Aconitum L.) by ethyl acetate extraction followed with counter-current chromatography. In the process of separation, the critical conditions of counter-current chromatography were optimized. The two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water/NH3 ·H2 O (25%) (1:1:1:1:0.1, v/v) was selected and 148.2 mg of 1, 24.1 mg of 2, 250.6 mg of 3, 73.9 mg of 4, and 31.4 mg of 5 were obtained from 1 g total Aconitum alkaloids extract, respectively, in a single run within 4 h. Their purities were found to be 98.4, 97.2, 98.2, 96.8, and 96.6%, respectively, by ultra-high performance liquid chromatography analysis. The presented separation and purification method was simple, fast, and efficient, and the obtained highly pure alkaloids are suitable for biochemical and toxicological investigation.

  6. Simultaneous separation of three isomeric sennosides from senna leaf (Cassia acutifolia) using counter-current chromatography.

    Science.gov (United States)

    Park, Sait Byul; Kim, Yeong Shik

    2015-10-01

    Senna leaf is widely consumed as tea to treat constipation or to aid in weight loss. Sennoside A, A1 , and B are dirheinanthrone glucosides that are abundant and the bioactive constituents in the plant. They are isomers that refer to the (R*R*), (S*S*), and (R*S*) forms of protons on C-10 and C-10' centers and it is difficult to refine them individually due to their structural similarities. The new separation method using counter-current chromatography successfully purified sennoside A, A1 , and B from senna leaf (Cassia acutifolia) while reversed-phase medium-pressure liquid chromatography yielded sennoside A only. n-Butanol/isopropanol/water (5:1:6, v/v/v) was selected as the solvent system for counter-current chromatography operation, and the partition coefficients were carefully determined by adding different concentrations of formic acid. High-resolution mass spectrometry and NMR spectroscopy were performed to verify the chemical properties of the compounds.

  7. Modelling of cross-flow membrane contactors: physical mass transfer processes

    NARCIS (Netherlands)

    Dindore, V.Y.; Brilman, D.W.F.; Versteeg, G.F.

    2005-01-01

    Traditionally, hollow fiber membrane contactors used for gas–liquid contacting were designed in a shell and tube configuration with shell-side fluid flowing parallel to the fiber-side fluid, either in co-current or counter-current pattern. The primary limitations of these so-called ‘parallel flow’ c

  8. High-speed countercurrent chromatography as a valuable tool to isolate C-glycosylflavones from Cecropia lyratiloba Miquel.

    Science.gov (United States)

    Oliveira, R R; Moraes, M C C; Castilho, R O; Valente, A P; Carauta, J P P; Lopes, D; Kaplan, M A C

    2003-01-01

    A new apigeninglycoside, apigenin 6-C-galactosyl-6"-O-beta-galactopyranoside (1), isoorientin, and a mixture of orientin and isovitexin were isolated from leaves of Cecropia lyratiloba by high-speed countercurrent chromatography using a solvent system containing ethyl acetate, butanol, methanol and water. The structural elucidation of 1 was based on NMR spectroscopy.

  9. Synthesis of medronic acid monoesters and their purification by high-performance countercurrent chromatography or by hydroxyapatite

    OpenAIRE

    Elina Puljula; Jouko Vepsäläinen; Petri A. Turhanen

    2016-01-01

    We achieved the synthesis of important medronic acid monoalkyl esters via the dealkylation of mixed trimethyl monoalkyl esters of medronic acid. Two methods were developed for the purification of medronic acid monoesters: 1) small scale (10–20 mg) purification by using hydroxyapatite and 2) large scale (tested up to 140 mg) purification by high-performance countercurrent chromatography (HPCCC).

  10. Synthesis of medronic acid monoesters and their purification by high-performance countercurrent chromatography or by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Elina Puljula

    2016-10-01

    Full Text Available We achieved the synthesis of important medronic acid monoalkyl esters via the dealkylation of mixed trimethyl monoalkyl esters of medronic acid. Two methods were developed for the purification of medronic acid monoesters: 1 small scale (10–20 mg purification by using hydroxyapatite and 2 large scale (tested up to 140 mg purification by high-performance countercurrent chromatography (HPCCC.

  11. Recent Development in High-speed Countercurrent Chromatography%高速逆流色谱研究进展

    Institute of Scientific and Technical Information of China (English)

    戴德舜; 王义明; 罗国安

    2001-01-01

    综述了近年来高速逆流色谱(HSCCC)在分析、半制备和制备分离天然产物、蛋白质、抗生素、无机物等领域的研究和应用进展,总结了适用于HSCCC的溶剂体系,并展望了HSCCC与质谱联用、pH区带逆流色谱和离子对逆流色谱新技术的应用前景。%This paper reviews recent development and applications of high-speed countercurrent chromatography (HSCCC) in the separations on the analytical scale,the semi-preparative and preparative scale of natural products,antibiotics,proteins,inorganic compounds etc.Several series of two-phase solvent systems to facilitate the systematic search suitable for HSCCC are introduced.And the new countercurrent chromatography (CCC)technologies such as HSCCC coupled with MS,pH-zone-refining countercurrent chromatography,and ion-pairing Countercurrent Chromatography are explained and prospected in term of applications.

  12. Field observations of turbulent dissipation rate profiles immediately below the air-water interface

    Science.gov (United States)

    Wang, Binbin; Liao, Qian

    2016-06-01

    Near surface profiles of turbulence immediately below the air-water interface were measured with a free-floating Particle Image Velocimetry (PIV) system on Lake Michigan. The surface-following configuration allowed the system to measure the statistics of the aqueous-side turbulence in the topmost layer immediately below the water surface (z≈0˜15 cm, z points downward with 0 at the interface). Profiles of turbulent dissipation rate (ɛ) were investigated under a variety of wind and wave conditions. Various methods were applied to estimate the dissipation rate. Results suggest that these methods yield consistent dissipation rate profiles with reasonable scattering. In general, the dissipation rate decreases from the water surface following a power law relation in the top layer, ɛ˜z-0.7, i.e., the slope of the decrease was lower than that predicted by the wall turbulence theory, and the dissipation was considerably higher in the top layer for cases with higher wave ages. The measured dissipation rate profiles collapse when they were normalized with the wave speed, wave height, water-side friction velocity, and the wave age. This scaling suggests that the enhanced turbulence may be attributed to the additional source of turbulent kinetic energy (TKE) at the "skin layer" (likely due to micro-breaking), and its downward transport in the water column.

  13. Interfacial Interactions and Nanostructure Changes in DPPG/HD Monolayer at the Air/Water Interface

    Directory of Open Access Journals (Sweden)

    Huaze Zhu

    2015-01-01

    Full Text Available Lung surfactant (LS plays a crucial role in regulating surface tension during normal respiration cycles by decreasing the work associated with lung expansion and therefore decreases the metabolic energy consumed. Monolayer surfactant films composed of a mixture of phospholipids and spreading additives are of optional utility for applications in lung surfactant-based therapies. A simple, minimal model of such a lung surfactant system, composed of 1,2-dipalmitoyl-sn-glycero-3-[phosphor-rac-(1-gylcerol] (DPPG and hexadecanol (HD, was prepared, and the surface pressure-area (π-A isotherms and nanostructure characteristics of the binary mixture were investigated at the air/water interface using a combination of Langmuir-Blodgett (LB and atomic force microscopy (AFM techniques. Based on the regular solution theory, the miscibility and stability of the two components in the monolayer were analyzed in terms of compression modulus (Cs-1 , excess Gibbs free energy (ΔGexcπ , activity coefficients (γ, and interaction parameter (ξ. The results of this paper provide valuable insight into basic thermodynamics and nanostructure of mixed DPPG/HD monolayers; it is helpful to understand the thermodynamic behavior of HD as spreading additive in LS monolayer with a view toward characterizing potential improvements to LS performance brought about by addition of HD to lung phospholipids.

  14. Investigation of adsorption of surfactant at the air-water interface with quantum chemistry method

    Institute of Scientific and Technical Information of China (English)

    CHEN MeiLing; WANG ZhengWu; WANG HaiJun; ZHANG GeXin; TAO FuMing

    2007-01-01

    Density functional theory (DFT) of quantum chemistry was used to optimize the configuration of the anionic surfactant complexes CH3(CH2)7OSO-3(H2O)n (n=0-6) and calculate their molecular frequencies at the B3LYP/6-311+G* level. The interaction of CH3(CH2)7OSO-3 with 1 to 6 water molecules was investigated at the air-water interface with DFT. The results revealed that the hydration shell was formed in the form of H-bond between the hydrophilic group of CH3(CH2)7OSO-3 and 6 waters. The strength of H-bonds belongs to medium. Binding free energy revealed that the hydration shell was stable. The increase of the number of water molecules will cause increases of the total charge of hydrophilic group and S10-O9-C8 bond angle, but decreases of the alkyl chain length and the bond lengths of S10-O11,S10-O12 as well as S10-O13, respectively.

  15. Dynamics of the free surface of stratified two-phase flows in channels with rectangular cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Vallee, Christophe

    2012-08-22

    Stratified two-phase flows were investigated at different test facilities with horizontal test sections in order to provide an experimental database for the development and validation of computational fluid dynamics (CFD) codes. These channels were designed with rectangular cross-sections to enable optimal observation conditions for the application of optical measurement techniques. Consequently, the local flow structure was visualised with a high-speed video camera, delivering data with highresolution in space and time as needed for CFD code validation. Generic investigations were performed at atmospheric pressure and room temperature in two air/water channels made of acrylic glass. Divers preliminary experiments were conducted with various measuring systems in a test section mounted between two separators. The second test facility, the Horizontal Air/Water Channel (HAWAC), is dedicated to co-current flow investigations. The hydraulic jump as the quasi-stationary discontinuous transition between super- and subcritical flow was studied in this closed channel. Moreover, the instable wave growth leading to slug flow was investigated from the test section inlet. For quantitative analysis of the optical measurements, an algorithm was developed to recognise the stratified interface in the camera frames, allowing statistical treatments for comparison with CFD calculation results. The third test apparatus was installed in the pressure chamber of the TOPFLOW test facility in order to be operated at reactor typical conditions under pressure equilibrium with the vessel atmosphere. The test section representing a flat model of the hot leg of the German Konvoi pressurised water reactor (PWR) scaled at 1:3 is equipped with large glass side walls in the region of the elbow and of the steam generator inlet chamber to allow visual observations. The experiments were conducted with air and water at room temperature and maximum pressures of 3 bar as well as with steam and water at

  16. Langmuir nanoarchitectonics: one-touch fabrication of regularly sized nanodisks at the air-water interface.

    Science.gov (United States)

    Mori, Taizo; Sakakibara, Keita; Endo, Hiroshi; Akada, Misaho; Okamoto, Ken; Shundo, Atsuomi; Lee, Michael V; Ji, Qingmin; Fujisawa, Takuya; Oka, Kenichiro; Matsumoto, Mutsuyoshi; Sakai, Hideki; Abe, Masahiko; Hill, Jonathan P; Ariga, Katsuhiko

    2013-06-18

    In this article, we propose a novel methodology for the formation of monodisperse regularly sized disks of several nanometer thickness and with diameters of less than 100 nm using Langmuir monolayers as fabrication media. An amphiphilic triimide, tri-n-dodecylmellitic triimide (1), was spread as a monolayer at the air-water interface with a water-soluble macrocyclic oligoamine, 1,4,7,10-tetraazacyclododecane (cyclen), in the subphase. The imide moieties of 1 act as hydrogen bond acceptors and can interact weakly with the secondary amine moieties of cyclen as hydrogen bond donors. The monolayer behavior of 1 was investigated through π-A isotherm measurements and Brewster angle microscopy (BAM). The presence of cyclen in the subphase significantly shifted isotherms and induced the formation of starfish-like microstructures. Transferred monolayers on solid supports were analyzed by reflection absorption FT-IR (FT-IR-RAS) spectroscopy and atomic force microscopy (AFM). The Langmuir monolayer transferred onto freshly cleaved mica by a surface touching (i.e., Langmuir-Schaefer) method contained disk-shaped objects with a defined height of ca. 3 nm and tunable diameter in the tens of nanometers range. Several structural parameters such as the disk height, molecular aggregation numbers in disk units, and 2D disk density per unit surface area are further discussed on the basis of AFM observations together with aggregate structure estimation and thermodynamic calculations. It should be emphasized that these well-defined structures are produced through simple routine procedures such as solution spreading, mechanical compression, and touching a substrate at the surface. The controlled formation of defined nanostructures through easy macroscopic processes should lead to unique approaches for economical, energy-efficient nanofabrication.

  17. Application of a laser Doppler vibrometer for air-water to subsurface signature detection

    Science.gov (United States)

    Land, Phillip; Roeder, James; Robinson, Dennis; Majumdar, Arun

    2015-05-01

    There is much interest in detecting a target and optical communications from an airborne platform to a platform submerged under water. Accurate detection and communications between underwater and aerial platforms would increase the capabilities of surface, subsurface, and air, manned and unmanned vehicles engaged in oversea and undersea activities. The technique introduced in this paper involves a Laser Doppler Vibrometer (LDV) for acousto-optic sensing for detecting acoustic information propagated towards the water surface from a submerged platform inside a 12 gallon water tank. The LDV probes and penetrates the water surface from an aerial platform to detect air-water surface interface vibrations caused by an amplifier to a speaker generating a signal generated from underneath the water surface (varied water depth from 1" to 8"), ranging between 50Hz to 5kHz. As a comparison tool, a hydrophone was used simultaneously inside the water tank for recording the acoustic signature of the signal generated between 50Hz to 5kHz. For a signal generated by a submerged platform, the LDV can detect the signal. The LDV detects the signal via surface perturbations caused by the impinging acoustic pressure field; proving a technique of transmitting/sending information/messages from a submerged platform acoustically to the surface of the water and optically receiving the information/message using the LDV, via the Doppler Effect, allowing the LDV to become a high sensitivity optical-acoustic device. The technique developed has much potential usage in commercial oceanography applications. The present work is focused on the reception of acoustic information from an object located underwater.

  18. 20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean.

    Science.gov (United States)

    Jantunen, Liisa M; Wong, Fiona; Gawor, Anya; Kylin, Henrik; Helm, Paul A; Stern, Gary A; Strachan, William M J; Burniston, Deborah A; Bidleman, Terry F

    2015-12-01

    The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water-air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

  19. Effect of glycyrrhetinic acid on lipid raft model at the air/water interface.

    Science.gov (United States)

    Sakamoto, Seiichi; Uto, Takuhiro; Shoyama, Yukihiro

    2015-02-01

    To investigate an interfacial behavior of the aglycon of glycyrrhizin (GC), glycyrrhetinic acid (GA), with a lipid raft model consisting of equimolar ternary mixtures of N-palmitoyl sphingomyelin (PSM), dioleoylphosphatidylcholine (DOPC), and cholesterol (CHOL), Langmuir monolayer techniques were systematically conducted. Surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms showed that the adsorbed GA at the air/water interface was desorbed into the bulk upon compression of the lipid monolayer. In situ morphological analysis by Brewster angle microscopy and fluorescence microscopy revealed that the raft domains became smaller as the concentrations of GA in the subphase (CGA) increased, suggesting that GA promotes the formation of fluid networks related to various cellular processes via lipid rafts. In addition, ex situ morphological analysis by atomic force microscopy revealed that GA interacts with lipid raft by lying down at the surface. Interestingly, the distinctive striped regions were formed at CGA=5.0 μM. This phenomenon was observed to be induced by the interaction of CHOL with adsorbed GA and is involved in the membrane-disrupting activity of saponin and its aglycon. A quantitative comparison of GA with GC (Sakamoto et al., 2013) revealed that GA interacts more strongly with the raft model than GC in the monolayer state. Various biological activities of GA are known to be stronger than those of GC. This fact allows us to hypothesize that differences in the interactions of GA/GC with the model monolayer correlate to their degree of exertion for numerous activities.

  20. Preparative Isolation of Three Anthraquinones from Rumex japonicus by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Shuying Guo

    2011-01-01

    Full Text Available Three anthraquinones—emodin, chrysophanol, and physcion—were successfully purified from the dichloromethane extract of the Chinese medicinal herb Rumex japonicus by high-speed counter-current chromatography (HSCCC. The extract was separated with n-hexane–ethanol–water (18:22:3, v/v/v as the two-phase solvent system and yielded 3.4 mg of emodin, 24.1 mg of chrysophanol, and 2.0 mg of physcion from 500 mg of sample with purities of 99.2 %, 98.8% and 98.2%, respectively. The HSCCC fractions were analyzed by high-performance liquid chromatography (HPLC and the chemical structures of the three anthraquinones were confirmed by 1H-NMR and 13C-NMR analysis. This is the first time these anthraquinones have been obtained from R. japonicus by HSCCC.

  1. Foam fractionation as a tool to study the air-water interface structure-function relationship of wheat gluten hydrolysates.

    Science.gov (United States)

    Wouters, Arno G B; Rombouts, Ine; Schoebrechts, Nele; Fierens, Ellen; Brijs, Kristof; Blecker, Christophe; Delcour, Jan A

    2017-03-01

    Enzymatic hydrolysis of wheat gluten protein improves its solubility and produces hydrolysates with foaming properties which may find applications in food products. First, we here investigated whether foam-liquid fractionation can concentrate wheat gluten peptides with foaming properties. Foam and liquid fractions had high and very low foam stability (FS), respectively. In addition, foam fractions were able to decrease surface tension more pronouncedly than un-fractionated samples and liquid fractions, suggesting they are able to arrange themselves more efficiently at an interface. As a second objective, foam fractionation served as a tool to study the structural properties of the peptides, causing these differences in air-water interfacial behavior. Zeta potential and surface hydrophobicity measurements did not fully explain these differences but suggested that hydrophobic interactions at the air-water interface are more important than electrostatic interactions. RP-HPLC showed a large overlap between foam and liquid fractions. However, a small fraction of very hydrophobic peptides with relatively high average molecular mass was clearly enriched in the foam fraction. These peptides were also more concentrated in un-fractionated DH 2 hydrolysates, which had high FS, than in DH 6 hydrolysates, which had low FS. These peptides most likely play a key role in stabilizing the air-water interface.

  2. Study on flow mode of combined converter for methanol synthesis from coal-based syngas

    Institute of Scientific and Technical Information of China (English)

    XIAO Zhen-ping; MA Hong-fang; YING Wei-yong; FANG Ding-ye

    2011-01-01

    The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established.The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that ifthe flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. Therefore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.

  3. Separation of polyphenols and caffeine from the acetone extract of fermented tea leaves (Camellia sinensis) using high-performance countercurrent chromatography.

    Science.gov (United States)

    Choi, Soo Jung; Hong, Yong Deog; Lee, Bumjin; Park, Jun Seong; Jeong, Hyun Woo; Kim, Wan Gi; Shin, Song Seok; Yoon, Kee Dong

    2015-07-21

    Leaves from Camellia sienensis are a popular natural source of various beverage worldwide, and contain caffeine and polyphenols derived from catechin analogues. In the current study, caffeine (CAF, 1) and three tea polyphenols including (-)-epigallocatechin 3-O-gallate (EGCg, 2), (-)-gallocatechin 3-O-gallate (GCg, 3), and (-)-epicatechin 3-O-gallate (ECg, 4) were isolated and purified by flow-rate gradient high-performance countercurrent chromatography (HPCCC) using a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:9:1:9, v/v). Two hundred milligrams of acetone-soluble extract from fermented C. sinensis leaves was separated by HPCCC to give 1 (25.4 mg), 2 (16.3 mg), 3 (11.1 mg) and 4 (4.4 mg) with purities over 98%. The structures of 1-4 were elucidated by QTOF-MS, as well as 1H- and 13C-NMR, and the obtained data were compared to the previously reported values.

  4. Scale-up protein separation on stainless steel wide bore toroidal columns in the type-J counter-current chromatography.

    Science.gov (United States)

    Guan, Yue Hugh; Hewitson, Peter; van den Heuvel, Remco N A M; Zhao, Yan; Siebers, Rick P G; Zhuang, Ying-Ping; Sutherland, Ian

    2015-12-11

    Manufacturing high-value added biotech biopharmaceutical products (e.g. therapeutic proteins) requires quick-to-develop, GMP-compliant, easy-to-scale and cost effective preparatory chromatography technologies. In this work, we describe the construction and testing of a set of 5-mm inner diameter stainless steel toroidal columns for use on commercially available preparatory scale synchronous J-type counter-current chromatography (CCC) machinery. We used a 20.2m long column with an aqueous two-phase system containing 14% (w/w) PEG1000 and 14% (w/w) potassium phosphate at pH 7, and tested a sample loading of 5% column volume and a mobile phase flow rate of 20ml/min. We then satisfactorily demonstrated the potential for a weekly protein separation and preparation throughput of ca. 11g based on a normal weekly routine for separating a pair of model proteins by making five stacked injections on a single portion of stationary phase with no stripping. Compared to our previous 1.6mm bore PTFE toroidal column, the present columns enlarged the nominal column processing throughput by nearly 10. For an ideal model protein injection modality, we observed a scaling up factor of at least 21. The 2 scales of protein separation and purification steps were realized on the same commercial CCC device.

  5. SEPARATION OF SATURED AND UNSATURATED FATTY ACIDS FROM PALM FATTY ACIDS DISTILLATES IN CONTINUOUS MULTISTAGE COUNTERCURRENT COLUMNS WITH SUPERCRITICAL CARBON DIOXIDE AS SOLVENT: A PROCESS DESIGN METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Nélio Teixeira MACHADO

    1997-12-01

    Full Text Available In this work the separation of multicomponent mixtures in counter-current columns with supercritical carbon dioxide has been investigated using a process design methodology. First the separation task must be defined, then phase equilibria experiments are carried out, and the data obtained are correlated with thermodynamic models or empirical functions. Mutual solubilities, Ki-values, and separation factors aij are determined. Based on this data possible operating conditions for further extraction experiments can be determined. Separation analysis using graphical methods are performed to optimize the process parameters. Hydrodynamic experiments are carried out to determine the flow capacity diagram. Extraction experiments in laboratory scale are planned and carried out in order to determine HETP values, to validate the simulation results, and to provide new materials for additional phase equilibria experiments, needed to determine the dependence of separation factors on concetration. Numerical simulation of the separation process and auxiliary systems is carried out to optimize the number of stages, solvent-to-feed ratio, product purity, yield, and energy consumption. Scale-up and cost analysis close the process design. The separation of palmitic acid and (oleic+linoleic acids from PFAD-Palm Fatty Acids Distillates was used as a case study.

  6. Preparative Isolation of Two Prenylated Biflavonoids from the Roots and Rhizomes of Sinopodophyllum emodi by Sephadex LH-20 Column and High-Speed Counter-Current Chromatography.

    Science.gov (United States)

    Sun, Yan-Jun; Pei, Li-Xin; Wang, Kai-Bo; Sun, Yin-Shi; Wang, Jun-Min; Zhang, Yan-Li; Gao, Mei-Ling; Ji, Bao-Yu

    2015-12-23

    Two prenylated biflavonoids, podoverines B-C, were isolated from the dried roots and rhizomes of Sinopodophyllum emodi using a Sephadex LH-20 column (SLHC) and high-speed counter-current chromatography (HSCCC). The 95% ethanol extract was partitioned with ethyl acetate in water. Target compounds from the ethyl acetate fraction were further enriched and purified by the combined application of SLHC and HSCCC. n-Hexane-ethyl acetate-methanol-water (3.5:5:3.5:5, v/v) was chosen as the two phase solvent system. The flow rate of mobile phase was optimized at 2.0 mL·min(-1). Finally, under optimized conditions, 13.8 mg of podoverine B and 16.2 mg of podoverine C were obtained from 200 mg of the enriched sample. The purities of podoverines B and C were 98.62% and 99.05%, respectively, as determined by HPLC. For the first time, podoverins B and C were found in the genus Sinopodophyllum. Their structures were determined by spectroscopic methods (HR-ESI-MS, ¹H-NMR, (13)C-NMR, HSQC, HMBC). Their absolute configurations were elucidated by comparison of their experimental and calculated ECD spectra. The cytotoxic activities were evaluated against MCF-7 and HepG2 cell lines. The separation procedures proved to be practical and economical, especially for trace prenylated biflavonoids from traditional Chinese medicine.

  7. Preparative Isolation of Two Prenylated Biflavonoids from the Roots and Rhizomes of Sinopodophyllum emodi by Sephadex LH-20 Column and High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Yan-Jun Sun

    2015-12-01

    Full Text Available Two prenylated biflavonoids, podoverines B–C, were isolated from the dried roots and rhizomes of Sinopodophyllum emodi using a Sephadex LH-20 column (SLHC and high-speed counter-current chromatography (HSCCC. The 95% ethanol extract was partitioned with ethyl acetate in water. Target compounds from the ethyl acetate fraction were further enriched and purified by the combined application of SLHC and HSCCC. n-Hexane–ethyl acetate–methanol–water (3.5:5:3.5:5, v/v was chosen as the two phase solvent system. The flow rate of mobile phase was optimized at 2.0 mL·min−1. Finally, under optimized conditions, 13.8 mg of podoverine B and 16.2 mg of podoverine C were obtained from 200 mg of the enriched sample. The purities of podoverines B and C were 98.62% and 99.05%, respectively, as determined by HPLC. For the first time, podoverins B and C were found in the genus Sinopodophyllum. Their structures were determined by spectroscopic methods (HR-ESI-MS, 1H-NMR, 13C-NMR, HSQC, HMBC. Their absolute configurations were elucidated by comparison of their experimental and calculated ECD spectra. The cytotoxic activities were evaluated against MCF-7 and HepG2 cell lines. The separation procedures proved to be practical and economical, especially for trace prenylated biflavonoids from traditional Chinese medicine.

  8. Predictable and linear scale-up of four phenolic alkaloids separation from the roots of Menispermum dauricum using high-performance counter-current chromatography.

    Science.gov (United States)

    Luo, Houding; Peng, Ming; Ye, Haoyu; Chen, Lijuan; Peng, Aihua; Tang, Minghai; Zhang, Fan; Shi, Jie

    2010-07-15

    This paper describes how distribution ratios were used for prediction of peak elution in analytical high-performance counter-current chromatography (HPCCC) to explore the method for separation and purification of bioactive compounds from the roots of Menispermum dauricum. Then important parameters related to HPCCC separations including solvent systems, sample concentration, sample loading volume and flow rate were optimized on an analytical Mini-DE HPCCC and finally linearly scaled up to a preparative Midi-DE HPCCC with nearly the same resolutions and separation time. Four phenolic alkaloids were for the first time obtained by HPCCC separation with a two-phase solvent system composed of petroleum ether-ethyl acetate-ethanol-water (1:2:1:2, v/v). This process produced 131.3 mg daurisolin, 197.1 mg dauricine, 32.4 mg daurinoline and 14.7 mg dauricicoline with the purity of 97.6%, 96.4%, 97.2% and 98.3%, respectively from 500 mg crude extract of the roots of M. dauricum in a one-step separation. The purities of compounds were determined by high-performance liquid chromatography (HPLC). Their structures were identified by electrospray ionization mass spectrometer (ESI-MS) and nuclear magnetic resonance (NMR).

  9. L-S mass transfer in G-L-S countercurrent magnetically stabilized bed with amorphous alloy SRNA-4 catalyst

    Institute of Scientific and Technical Information of China (English)

    Wei; Li; Baoning; Zong; Xiaofang; Li; Xiangkun; Meng; Jinli; Zhang

    2007-01-01

    Liquid-solid (L-S) mass transfer coefficients (Ks) were characterized in a gas-liquid-solid (G-L-S) three-phase countercurrent magnetically stabilized bed (MSB) using amorphous alloy SRNA-4 as the solid phase. Effects of superficial liquid velocity, superficial gas velocity, magnetic field strength, liquid viscosity and surface tension were investigated. Experimental results indicated that the external magnetic field increased Ks in three-phase MSB, as compared to those in conventional G-L-S fluidized beds; that Ks increased with magnetic field strength, superficial gas and liquid velocities and decreased with liquid viscosity and surface tension; and that Ks showed uniform axial and radial distributions except for small increases close to the wall. Dimensionless correlations were established to estimate Ks of the G-L-S countercurrent MSB using SRNA-4catalyst, with an average error of 3.6%.

  10. Effect of the Shape Factor as an Input Variable on the Extraction Process for a Reversing Continuous Countercurrent Extractor

    Directory of Open Access Journals (Sweden)

    Waigoon RITTIRUT

    2010-06-01

    Full Text Available The effect of the shape factor on a reversing continuous countercurrent extraction process for concentration profiles is reported. Garcinia fruit was selected as a model solid while sucrose was used as soluble solid for the diffusion system. The results showed that a slab shape gave better results on the concentration profiles for both solid and liquid phases than those of the block shape. A better diffusion mass transfer in the slab shape leads to a better yield. The shape factor results were verified using a model solid system. The phenomena in reversing continuous countercurrent extraction process under steady-state conditions can be explained via a backmixing-diffusion model. The concentration profiles by model prediction corresponded well to those of measured data. Diffusivities which are available for simulation purposes were reported for different thicknesses and operating temperatures. The evaporation took place at an acceptable level for an open system according to the specified operating conditions.

  11. Noise abatement in air-water heat pump systems. Basic considerations, guidelines for practice; Laermreduktion bei Luft/Wasser-Waermepumpenanlagen. Grundlagen und Massnahmen

    Energy Technology Data Exchange (ETDEWEB)

    Graf, H.R.

    2002-07-01

    With increasing numbers of installations of air/water heat pumps the issue of noise emissions is becoming more of a concern. In reaction to this situation, the company Sulzer Innotec has developed these guidelines by order of the Swiss Federal Office of Energy. Typically, more than 90% of the noise emitted outdoors is produced by the fan. Due to the strong tonal components, the noise emitted is substantially more annoying than a reference broadband noise of the same intensity. For further noise reduction mainly the fan noise must be addressed. Despite the dominance of fan noise, other noise sources must not be neglected. The most promising countermeasures are: Reduction of fan noise by (i) low blade tip speed (prerequisite is a pressure drop in the air channels including the evaporator as low as possible), (ii) improvement of flow geometry in the vicinity of the fan, (iii) insulation of air ducts with acoustic foam (thickness 50 mm or more), (iv) elbows in the air duct line for sound dissipation. Reduction of compressor noise by (i) a highly effective acoustic enclosure, (ii) vibration insulation of structure-borne noise by elastic mounts, (iii) decoupling of refrigerant pipes. (author)

  12. Air/water heat pumps in older buildings. Energy conservation in a stock; Luft/Wasser-Waermepumpen im Altbau. Energiesparen im Bestand

    Energy Technology Data Exchange (ETDEWEB)

    Bauknecht, Steffen [Mitsubishi Electric, Ratingen (Germany)

    2010-02-15

    Due to the technical development, nowadays it is possible to heat older buildings which are not insulated thermally subsequently with monovalent air/water heat pumps. For example, in Bonn-Oberkassel (Federal Republic of Germany) a nearly one hundred year old art nouveau mansion is supplied with apartment warmth and warm water by means of two air/water heat pumps. The economical heat supply as well as the small structural expenditure decided to use this technology.

  13. Preparative Separation of Six Rhynchophylla Alkaloids from Uncaria macrophylla Wall by pH-Zone Refining Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Qinghai Zhang

    2013-12-01

    Full Text Available pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether–ethyl acetate–isopropanol–water (2:6:3:9, v/v, adding 10 mM triethylamine in organic stationary phase and 5 mM hydrochloric acid in aqueous mobile phase. Then pH-zone refining counter-current chromatography using the other two-phase solvent system was used for final purification. Six target compounds were finally isolated and purified by following two-phase solvent system composed of methyl tert-butyl ether (MTBE–acetonitrile–water (4:0.5:5, v/v, adding triethylamine (TEA (10 mM to the organic phase and HCl (5 mM to aqueous mobile phase. The separation of 2.8 g enriched total alkaloids yielded 36 mg hirsutine, 48 mg hirsuteine, 82 mg uncarine C, 73 mg uncarine E, 163 mg rhynchophylline, and 149 mg corynoxeine, all with purities above 96% as verified by HPLC Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS and 1H-NMR spectroscopy.

  14. Towards Organized Hybrid Nanomaterials at the Air/Water Interface Based on Liquid-Crystal/ZnO Nanocrystals.

    Science.gov (United States)

    Paczesny, Jan; Wolska-Pietkiewicz, Małgorzata; Binkiewicz, Ilona; Wróbel, Zbigniew; Wadowska, Monika; Matuła, Kinga; Dzięcielewski, Igor; Pociecha, Damian; Smalc-Koziorowska, Julita; Lewiński, Janusz; Hołyst, Robert

    2015-11-16

    The ability to self-assemble nanosized ligand-stabilized metal oxide or semiconductor materials offers an intriguing route to engineer nanomaterials with new tailored properties from the disparate components. We describe a novel one-pot two-step organometallic approach to prepare ZnO nanocrystals (NCs) coated with deprotonated 4-(dodecyloxy)benzoic acid (i.e., an X-type liquid-crystalline ligand) as a model LC system (termed ZnO-LC1 NCs). Langmuir and Langmuir-Blodgett films of the resulting hybrids are investigated. The observed behavior of the ZnO NCs at the air/water interface is rationalized by invoking a ZnO-interdigitation process mediated by the anchored liquid-crystalline shell. The ordered superstructures form according to mechanism based on a ZnO-interdigitation process mediated by liquid crystals (termed ZIP-LC). The external and directed force applied upon compression at the air/water interface and the packing of the ligands that stabilize the ZnO cores drives the formation of nanorods of ordered internal structure. To study the process in detail, we follow a nontraditional protocol of thin-film investigation. We collect the films from the air/water interface in powder form (ZnO-LC1 LB), resuspend the powder in organic solvents and utilize otherwise unavailable experimental techniques. The structural and physical properties of the resulting superlattices were studied by using electron microscopy, atomic force microscopy, X-ray studies, dynamic light scattering, thermogravimetric analysis, UV/Vis absorption, and photoluminescence spectroscopy.

  15. Removal of cesium from simulated liquid waste with countercurrent two-stage adsorption followed by microfiltration

    Energy Technology Data Exchange (ETDEWEB)

    Han, Fei; Zhang, Guang-Hui [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China); Gu, Ping, E-mail: guping@tju.edu.cn [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer The adsorption isotherm of cesium by copper ferrocyanide followed a Freundlich model. Black-Right-Pointing-Pointer Decontamination factor of cesium was higher in lab-scale test than that in jar test. Black-Right-Pointing-Pointer A countercurrent two-stage adsorption-microfiltration process was achieved. Black-Right-Pointing-Pointer Cesium concentration in the effluent could be calculated. Black-Right-Pointing-Pointer It is a new cesium removal process with a higher decontamination factor. - Abstract: Copper ferrocyanide (CuFC) was used as an adsorbent to remove cesium. Jar test results showed that the adsorption capacity of CuFC was better than that of potassium zinc hexacyanoferrate. Lab-scale tests were performed by an adsorption-microfiltration process, and the mean decontamination factor (DF) was 463 when the initial cesium concentration was 101.3 {mu}g/L, the dosage of CuFC was 40 mg/L and the adsorption time was 20 min. The cesium concentration in the effluent continuously decreased with the operation time, which indicated that the used adsorbent retained its adsorption capacity. To use this capacity, experiments on a countercurrent two-stage adsorption (CTA)-microfiltration (MF) process were carried out with CuFC adsorption combined with membrane separation. A calculation method for determining the cesium concentration in the effluent was given, and batch tests in a pressure cup were performed to verify the calculated method. The results showed that the experimental values fitted well with the calculated values in the CTA-MF process. The mean DF was 1123 when the dilution factor was 0.4, the initial cesium concentration was 98.75 {mu}g/L and the dosage of CuFC and adsorption time were the same as those used in the lab-scale test. The DF obtained by CTA-MF process was more than three times higher than the single-stage adsorption in the jar test.

  16. Optical characterization of bubbly flows with a near-critical-angle scattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Onofri, Fabrice R.A.; Krzysiek, Mariusz [IUSTI, UMR, CNRS, University of Provence, Polytech' DME, Technopole Chateau-Gombert, Marseille (France); Mroczka, Janusz [CEPM, Technical University of Wroclaw, Wroclaw (Poland); Ren, Kuan-Fang [CORIA, UMR, CNRS, University of Rouen, Saint-Etienne-du-Rouvray (France); Radev, Stefan [IMECH, Bulgarian Academy of Sciences, Sofia (Bulgaria); Bonnet, Jean-Philippe [M2P2, UMR, CNRS, University Paul Cezanne, Aix-en-Provence (France)

    2009-10-15

    The newly developed critical angle refractometry and sizing technique (CARS) allows simultaneous and instantaneous characterization of the local size distribution and the relative refractive index (i.e. composition) of a cloud of bubbles. The paper presents the recent improvement of this technique by comparison of different light scattering models and inversion procedures. Experimental results carried in various air/water and air/water-ethanol bubbly flows clearly demonstrate the efficiency and the potential of this technique. (orig.)

  17. Numerical Simulation of Unsteady Discharge Flow with Fluctuation in Positive Discharge Blower

    Institute of Scientific and Technical Information of China (English)

    LIU Zhengxian; WANG Dou; XU Lianhuan

    2009-01-01

    The operating performance of positive discharge blower/s markedly influenced by the pulsation of the discharge flow, but difficult to be measured with experimental methods. The internal and discharge flow of positive discharge blower with involute type three-lobe are numerically investigated, both in air cooling and countercurrent cooling conditions by means of computational fluid dynamics (CFD). The unsteady compressible flow equations are solved using RNG κ-ε turbulent model. The finite difference method and the second order upwind difference scheme are applied into discrete equations. In the numerical simulation, the dynamic mesh techniques are used to approach the rotating displacement of cell cubage and the alterability of inlet, outlet flow area. The non-uniform mesh is applied to the rotor-stator coupled area. The reliability of the numerical method is verified by simulating the inner flow and comparing with the semi-empirical theory. The flow flux curves and the distributing of velocity vector showed obvious vortex motion in all the discharge process, both in air cooling and countercurrent cooling conditions. These vortexes with different positions, intension and numbers at different rotating angles have remarkable influences on the discharge flux. For air cooling, the vortex produced a second pulsation with big-amplitude in a cycle, and led to the early appearance of maximum of backflow. For countercurrent cooling, the frequency of pulsation increased due to the pre-inflow, but the hackflow at the outlet is prevented, also the pulsation strength has greatly decreased.

  18. Collapsed bipolar glycolipids at the air/water interface: effect of the stereochemistry on the stretched/bent conformations.

    Science.gov (United States)

    Jacquemet, Alicia; Terme, Nolwenn; Benvegnu, Thierry; Vié, Véronique; Lemiègre, Loïc

    2013-12-15

    This article describes a comparative study of several bipolar lipids derived from tetraether structures. The sole structural difference between the main two glycolipids is a unique stereochemical variation on a cyclopentyl ring placed in the middle of the lipids. We discuss the comparative results obtained at the air/water interface on the basis of tensiometry and ellipsometry. Langmuir-Blodgett depositions during lipid film compressions and decompressions were also analyzed by AFM. The lactosylated tetraether (bipolar) lipid structures involved the formation of highly stable multilayers, which are still present at 10 mN m(-1) during decompression. This study suggests also that the stereochemistry of a central cyclopentyl ring dramatically drives the conformation of the corresponding bipolar lipids. Both isomers (trans and cis) adopt a U-shaped (bent) conformation at the air/water interface but the trans cyclopentyl ring induces a much more frustration within this type of conformation. Consequently, this bipolar lipid (trans-tetraether) undergoes a flip of one polar head-group (lactosyl) leading to a stretched conformation during collapse.

  19. PREPARATION OF PERFLUOROOCTANOYL-MODIFIEDPOLY(VINYL-ALCOHOL)S AND THEIR ADSORPTION AT AN AIR-WATER INTERFACE

    Institute of Scientific and Technical Information of China (English)

    Pu-xin Zhu; Xiang-dong Luo; Rui-xia Li; Dac-heng Wu

    2002-01-01

    Perfluorooctanoyl modified poly(vinyl alcohol)s (FPVA) were prepared by means of substituting a small amount of hydroxyl groups on the backbone of poly(vinyl alcohol), for which the initial degree of polymerization is equal to 1750. The substitution extent, defined by the number of substituting units in a chain, for the four FPVA samples was in the range of 0.5-5 perfluorooctanoyl groups per chain. The FPVA samples with the highest substitution extent still had good solubility in water. It was shown by experimental measurement at 30.0±0.1 C that the surface tension of the aqueous solution of the highest substituted FPVA decreased to 16.6 mN/m at a higher concentration, e.g. about 0.1 g/mL. Obviously,macromolecules of FPVA exhibit a very strong tendency to adsorb at the air-water interface, because the hydrophobic perfluorooctanoyl groups in FPVA have a very high surface activity as they are in small molecular fluorinated surfactants.The chain conformation of such a model polymer adsorbed on the air-water interface was also discussed.

  20. Galaxy-like organization of floaters at the air-water interface of Faraday waves

    Science.gov (United States)

    Alarcón, Héctor; Périnet, Nicolas; Gutiérrez, Pablo; Gordillo, Leonardo; Mujica, Nicolás

    2016-11-01

    The fluid properties mismatch across an air-liquid interface allows to trap particles at it. These particles are called floaters and appear in nature at different scales: plankton, organic residues, and garbage, all relevant for the oceanic ecosystem. In static systems they tend to attract or repel each other, depending on their wetting properties and buoyancy. When they are subjected to a flow, such as surface waves, they may drift and form structures at the interface. In a recent work using PIV on Faraday waves, we have measured a streaming flow that emerges inside the bulk, leading to a slow circulation of fluid particles across the liquid. The flow is mainly generated by the viscous shearing at the walls of the container. Our new experiments show that this flow has a remarkable effect on the drift of small hydrophilic particles (floaters), which leads to a rare arrangement of the floaters that resemble rotating galaxies. The forcing amplitude determines the galaxy shape, controlling the number and the length of its arms as well as its rotation velocity. Thanks to FONDECYT POSTDOCTORADO N°3160341, N°3140522, N°3140550.

  1. Isolation of terpenoids from Pimpinella anisum essential oil by high-performance counter-current chromatography.

    Science.gov (United States)

    Skalicka-Woźniak, Krystyna; Walasek, Magdalena; Ludwiczuk, Agnieszka; Głowniak, Kazimierz

    2013-08-01

    High-performance counter-current chromatography was successfully used for the isolation and purification of terpenoid compounds from the essential oil of Pimpinella anisum L. A two-phase solvent system composed of n-heptane/methanol/ethyl acetate/water (5:2:5:2, v/v/v/v) was suitable for the purification of linalool, terpinen-4-ol, α-terpineol, p-anisaldehyde, while n-heptane/methanol (1:1, v/v) was used for the isolation of anethole and foeniculin. A scale-up process from analytical to preparative was developed. Additionally, a stepwise gradient elution was applied and instead of two different runs, 40 min each, one 80 min separation was performed; although the time of separation remains the same, it was possible to repeat the efficiency even if the water-containing mobile phase was changed to a nonaqueous system. The obtained essential oil, as well as purified compounds, was analyzed by GC. A total of 0.64 mg of linalool, 0.52 mg of terpinen-4-ol, 0.10 mg of α-terpineol, 0.62 mg of p-anisaldehyde, 15 mg of anethole, and 2.12 mg of foeniculin were obtained from 210 mg of the essential oil of P. anisum L. in a short time with purities of 99, 98, 94, 93.54, 93, and 93.6%, respectively.

  2. Effect of Coriolis force on counter-current chromatographic separation by centrifugal partition chromatography.

    Science.gov (United States)

    Ikehata, Jun-Ichi; Shinomiya, Kazufusa; Kobayashi, Koji; Ohshima, Hisashi; Kitanaka, Susumu; Ito, Yoichiro

    2004-02-06

    The effect of Coriolis force on the counter-current chromatographic separation was studied using centrifugal partition chromatography (CPC) with four different two-phase solvent systems including n-hexane-acetonitrile (ACN); tert-butyl methyl ether (MtBE)-aqueous 0.1% trifluoroacetic acid (TFA) (1:1); MtBE-ACN-aqueous 0.1% TFA (2:2:3); and 12.5% (w/w) polyethylene glycol (PEG) 1000-12.5% (w/w) dibasic potassium phosphate. Each separation was performed by eluting either the upper phase in the ascending mode or the lower phase in the descending mode, each in clockwise (CW) and counterclockwise column rotation. Better partition efficiencies were attained by the CW rotation in both mobile phases in all the two-phase solvent systems examined. The mathematical analysis also revealed the Coriolis force works favorably under the CW column rotation for both mobile phases. The overall results demonstrated that the Coriolis force produces substantial effects on CPC separation in both organic-aqueous and aqueous-aqueous two-phase systems.

  3. Topsy-turvy: Turning the counter-current heat exchange of leatherback turtles upside down

    Science.gov (United States)

    Davenport, John; Jones, T. Todd; Work, Thierry M.; Balazs, George H.

    2015-01-01

    Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting.

  4. Preparative Separation of Phenolic Compounds from Halimodendron halodendron by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Zhu Yu

    2010-08-01

    Full Text Available Three phenolic compounds, p-hydroxybenzoic acid (1, isorhamnetin-3-O-β-D-rutinoside (2, and 3,3'-di-O-methylquercetin (5, along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH-20 to afford quercetin (3 and 3-O-methylquercetin (4. Seven hundred mg of ethyl acetate crude extract was separated by HSCCC to obtain six fractions which were then analyzed by high performance liquid chromatography (HPLC. The HSCCC separation obtained total of 80 mg of the mixture of quercetin (3 and 3-O-methylquercetin (4 (26.43% and 71.89%, respectively in fraction 2, 14 mg of 3,3'-di-O-methylquercetin (5 at 95.14% of purity in fraction 3, 15 mg of p-hydroxybenzoic acid (1 at 92.83% of purity in fraction 5, 12 mg of isorhamnetin-3-O-β-D-rutinoside (2 at 97.99% of purity in fraction 6. This is the first time these phenolic compounds have been obtained from H. halodendron, and their chemical structures identified by means of physicochemical and spectrometric analysis.

  5. NON-ZONAL BAROCLINIC INSTABILITY IN THE NORTH PACIFIC SUBTROPICAL COUNTERCURRENT

    Institute of Scientific and Technical Information of China (English)

    LU Yan; LUO De-hai

    2004-01-01

    Observations indicated that in the region of the Subtropical Countercurrent(STCC)over the Pacific(140°E-170°W,19°N-28°N),the eddy kinetic energy over the western side is much higher than that over the eastern side.The cause of such a behavior was theoretically investigated in this paper.The calculation of geostrophic current in this region indicates that there are relatively strong meridional geostrophic currents in this region even though the zonal current is dominant in most seasons.Using a 2.5-layer reduced-gravity model,baroclinic instability of non-zonal current was discussed.It is found that at the western side of STCC the vertical shear of the meridional geostrophic current will be in favor of the baroclinic instability,but at its eastern side it will suppress baroclinic instability,thus causing the growth of eddies over the western side much faster than that over the eastern side.

  6. Effect of Some Operating Parameters on the Reversing Continuous Countercurrent Extraction Process

    Directory of Open Access Journals (Sweden)

    Waigoon RITTIRUT

    2009-06-01

    Full Text Available The effect of some operating parameters on the reversing continuous countercurrent extraction process including the degree of inclination of the extractor and the percent forward progression by a screw conveyor was reported. Garcinia fruit was selected as model solid while sucrose was used as soluble solid for the diffusion system. The results showed that the degree of inclination provided certain effect on concentration profile, however was still ambiguous. For experimental purpose, 5, 7 or 10° can be used. Nevertheless, the solid and liquid phase were not in contact at the end point of the extraction unit in the case of 7° and 10° where the specified draft was 1.6. Based on the highest yield, a slope of 10° should be chosen. For a percent forward progression range of 10 - 20 %, the concentration profiles for both liquid and solid phase were almost identical. However, the lowest 5 % percent forward progression led to highest concentration profile for the liquid phase.Keywords:

  7. Minimum amount of extracting solvent of AB/BC countercurrent extraction separation using organic feed

    Institute of Scientific and Technical Information of China (English)

    程福祥; 吴声; 张玻; 刘艳; 王嵩龄; 廖春生; 严纯华

    2014-01-01

    For an AB/BC countercurrent extraction separation using organic feed, the conditions to have minimum amount of ex-tracting solvent (Smin) and minimum amount of scrubbing agent solution (Wmin) were discussed, and the formulae of bothSmin and Wmin were deduced. It was shown that only when the ratio of flowrate of central component B leaving aqueous outlet to that leaving organic outlet took a certain optimal value, the AB/BC separation could have Smin as well asWmin, and this optimal ratio was decided by the separation factors between the three components but independent of feed composition.Smin was only relative to the separation factor of A/C pair but regardless of the separation factors of other pairs as well as feed composition, whereasWmin was determined by the separation factors between the components together with feed composition. Meanwhile it was also found that the organic stream out of feed stage was same composition as the initial organic feed when the separation system was given by the two minimum amounts and its steady state was achieved. Finally the results above were used to design a LuYb/YbTm separation case and the stage-wise compositions of each component in both the organic and the aqueous phase at steady state were given by computer simulation.

  8. Pulsed counter-current ultrasound-assisted extraction and characterization of polysaccharides from Boletus edulis.

    Science.gov (United States)

    You, Qinghong; Yin, Xiulian; Ji, Chaowen

    2014-01-30

    Four methods for extracting polysaccharides from Boletus edulis, namely, hot-water extraction, ultrasonic clearer extraction, static probe ultrasonic extraction, and pulsed counter-current probe ultrasonic extraction (CCPUE), were studied. Results showed that CCPUE has the highest extraction efficiency among the methods studied. Under optimal CCPUE conditions, a B. edulis polysaccharide (BEP) yield of 8.21% was obtained. Three purified fractions, BEP-I, BEP-II, and BEP-III, were obtained through sequential purification by DEAE-52 and Sephadex G-75 chromatography. The average molecular weights of BEP-I, BEP-II, and BEP-III were 10,278, 23,761, and 42,736 Da, respectively. The polysaccharides were mainly composed of xylose, mannose, galactose, and glucose; of these, mannose contents were the highest. The antioxidant activities of the BEPs were further investigated by measurement of their ability to scavenge DPPH and hydroxyl radicals as well as their reducing power. The results indicated that the BEPs have good antioxidant activity.

  9. Continuous counter-current chromatography for capture and polishing steps in biopharmaceutical production.

    Science.gov (United States)

    Steinebach, Fabian; Müller-Späth, Thomas; Morbidelli, Massimo

    2016-09-01

    The economic advantages of continuous processing of biopharmaceuticals, which include smaller equipment and faster, efficient processes, have increased interest in this technology over the past decade. Continuous processes can also improve quality assurance and enable greater controllability, consistent with the quality initiatives of the FDA. Here, we discuss different continuous multi-column chromatography processes. Differences in the capture and polishing steps result in two different types of continuous processes that employ counter-current column movement. Continuous-capture processes are associated with increased productivity per cycle and decreased buffer consumption, whereas the typical purity-yield trade-off of classical batch chromatography can be surmounted by continuous processes for polishing applications. In the context of continuous manufacturing, different but complementary chromatographic columns or devices are typically combined to improve overall process performance and avoid unnecessary product storage. In the following, these various processes, their performances compared with batch processing and resulting product quality are discussed based on a review of the literature. Based on various examples of applications, primarily monoclonal antibody production processes, conclusions are drawn about the future of these continuous-manufacturing technologies.

  10. Isolation of anti-HIV-1 lignans from Larrea tridentata by counter-current chromatography.

    Science.gov (United States)

    Gnabre, J N; Ito, Y; Ma, Y; Huang, R C

    1996-01-08

    Several lignans, mostly new, were isolated from Larrea tridentata by assay-guided counter-current chromatography (CCC). Using the secreted alkaline phosphatase bioassay of HIV Tat transactivation and the two-phase hexane-ethyl acetate-methanol-water solvent system, two major components (Gr and Lo) were identified as anti-HIV active principles. The chemical structures of the constituents of Gr (G1-G4) and Lo (L1-L4) were determined by GC-MS and NMR. After optimization of isolation conditions, a large-scale isolation with the chloroform-methanol-water system yielded five constituents (FB1-FB5). The most predominant anti-HIV compound FB2 (denoted Malachi 4:5-6 or mal.4), which occurs in 0.23% yield, was separated from its FB1 isomer (0.13% yield). Compound FB4 and two tricyclic lignans (FB3 and FB5) were also isolated in a substantial amount for further testing of their anti-HIV activities. These compounds may represent a new class of anti-HIV agents with important clinical relevance.

  11. Experimental analysis of ultrasonic signals in air-water vertical upward for void fraction measurement using neural networks; Analise experimental dos sinais ultra-sonicos em escoamentos verticais bifasicos para medicao da fracao de vazios atraves de redes neurais

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Milton Y.; Massignan, Joao P.D.; Daciuk, Rafael J.; Neves Junior, Flavio; Arruda, Lucia V.R. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2008-07-01

    Rheology of emulsion mixtures and void fraction measurements of multiphase flows requires proper instrumentation. Sometimes it is not possible to install this instrumentation inside the pipe or view the flow. Ultrasound technology has characteristics compatible with the requirements of the oil industry. It can assist the production of heavy oil. This study provides important information for an analysis of the feasibility of developing non-intrusive equipment. These probes can be used for measurement of multiphase void fraction and detect the flow pattern using ultrasound. Experiments using simulated upward air-water vertical two-phase flow show that there is a correlation between the acoustic attenuation and the concentration of the gas phase. Experimental data were obtained through the prototype developed for ultrasonic data acquisition. This information was processed and used as input parameters for a neural network classifier. Void fractions ({proportional_to}) were analyzed between 0% - 16%, in increments of 1%. The maximum error of the neural network for the classification of the flow pattern was 6%. (author)

  12. Surface Shear Viscosity and Phase Transitions of Monolayers at the Air-Water Interface

    Science.gov (United States)

    Relini, A.; Ciuchi, F.; Rolandi, R.

    1995-08-01

    The canal method has been employed to measure the in-plane steady shear viscosity of monolayers of bolaform lipids extracted from the membrane of the thermophilic microorganism Sulfolobus solfataricus. Monolayers were formed with the polar lipid extract (PLE), which is a mixture of several bolaform lipids, each one endowed with two nonequivalent polar headgroups. Viscosities were obtained from the measured flows by using the equation introduced by Joly; this equation contains a semiempirical parameter A, which takes into account the monolayer-subphase mechanical coupling. Measuring the flows for two different substances (PLE and oleic acid) and channel widths, the monolayer viscosities and the parameter A were determined at the same time. The analysis of the viscosity data according to the free area model shows evidences of the molecular conformational changes matching monolayer phase transitions.

  13. Gas liquid flow at microgravity conditions - Flow patterns and their transitions

    Science.gov (United States)

    Dukler, A. E.; Fabre, J. A.; Mcquillen, J. B.; Vernon, R.

    1987-01-01

    The prediction of flow patterns during gas-liquid flow in conduits is central to the modern approach for modeling two phase flow and heat transfer. The mechanisms of transition are reasonably well understood for flow in pipes on earth where it has been shown that body forces largely control the behavior observed. This work explores the patterns which exist under conditions of microgravity when these body forces are suppressed. Data are presented which were obtained for air-water flow in tubes during drop tower experiments and Learjet trajectories. Preliminary models to explain the observed flow pattern map are evolved.

  14. The Marangoni flow of soluble amphiphiles

    CERN Document Server

    Roché, Matthieu; Griffiths, Ian M; Roux, Sébastien Le; Cantat, Isabelle; Saint-Jalmes, Arnaud; Stone, Howard A

    2013-01-01

    Surfactant distribution heterogeneities at a fluid/fluid interface trigger the Marangoni effect, i.e. a bulk flow due to a surface tension gradient. The influence of surfactant solubility in the bulk on these flows remains incompletely characterized. Here we study Marangoni flows sustained by injection of hydrosoluble surfactants at the air/water interface. We show that the flow extent increases with a decrease of the critical micelle concentration, i.e. the concentration at which these surfactants self-assemble in water. We document the universality of the surface velocity field and predict scaling laws based on hydrodynamics and surfactant physicochemistry that capture the flow features.

  15. Scale-up of counter-current chromatography: demonstration of predictable isocratic and quasi-continuous operating modes from the test tube to pilot/process scale.

    Science.gov (United States)

    Sutherland, Ian; Hewitson, Peter; Ignatova, Svetlana

    2009-12-11

    Predictable scale-up from test tube derived distribution ratios and analytical-scale sample loading optimisation is demonstrated using a model sample system of benzyl alcohol and p-cresol in a heptane:ethyl acetate:methanol:water phase system with the new 18 L Maxi counter-current chromatography centrifuge. The versatility of having a liquid stationary phase with its high loading capacity and flexible operating modes is demonstrated at two different scales by separating and concentrating target compounds using a mixture of caffeine, vanillin, naringenin and carvone using a quasi-continuous technique called intermittent counter-current extraction.

  16. It's Alive! Spontaneous Motion of Shear Thickening Fluids Floating on the Air-Water Interface

    CERN Document Server

    Khandavalli, Sunilkumar; Rothstein, Jonathan P

    2013-01-01

    In this fluid dynamics video, we show the spontaneous random motion of thin filaments of a shear-thickening colloidal dispersions floating on the surface of water. The fluid is a dispersion of fumed silica nanoparticles in a low molecular weight polypropylene glycol (PPG) solvent. No external field or force is applied. The observed motion is driven by strong surface tension gradients as the polypropylene glycol slowly diffuses from from the filaments into water, resulting in the observed Marangoni flow. The motion is exaggerated by the thin filament constructs by the attractive interactions between silica nanoparticles and the PPG.

  17. Drainage of the air-water-quartz film: experiments and theory.

    Science.gov (United States)

    Manica, Rogerio; Chan, Derek Y C

    2011-01-28

    Experimental results of the kinetics of drainage of the trapped water film between an approaching air bubble and a quartz plate have been analysed using recent theoretical advances in formulating and solving the flow problem in deformable films. Excellent agreement is obtained between experimental data and a model that assumes the bubble-water interface is tangentially immobile in its hydrodynamic response. The coupling between hydrodynamic pressure, disjoining pressure and film deformation is critical in determining the dynamic behaviour of the drainage process. The Reynolds parallel film model that omits the effects of film deformation predicts results that are qualitatively incorrect.

  18. ISOLATION AND PUNRIFICATION OF PSORALEN AND BERGAPTEN FROM FICUS CARICA L LEAVES BY HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHY

    OpenAIRE

    Chunyan, Chi; Bo, Shi; Ping, Liang; Jingmei, Li; Ito, Yoichiro

    2009-01-01

    High-speed countercurrent chromatography was successfully applied for the first time for the separation of psoralen and bergapten from Ficus carica L leaves. The crudeextract obtained by light petroleum (b.p.: 60°C-90°C) from the dried leaves of Ficus carica L. was separated with a two-phase solvent system of n-Hexane-ethyl acetate-methanol-water (1:1:1:1, v/v). Each peak fraction was analyzed by high-performance liquid chromatography. The method yielded 4.4 mg of psoralen at 99.1% purity and...

  19. Preparative isolation and purification of harpagoside from Scrophularia ningpoensis hemsley by high-speed counter-current chromatography.

    Science.gov (United States)

    Tong, Shengqiang; Yan, Jizhong; Lou, Jianzhong

    2006-01-01

    The bioactive component harpagoside was successfully separated from the crude extract of Scrophularia ningpoensis Hemsley by one-step purification using high-speed counter-current chromatography (HSCCC). A two-phase solvent system containing n-butanol:ethyl acetate:water (1:9:10) was selected following consideration of the partition coefficient of the target compound. A 276 mg quantity of the crude extract was loaded onto a 250 mL HSCCC column and yielded 11 mg harpagoside at over 97% purity. The chemical structure of harpagoside was determined by HPLC-ESI/MS and 1H-NMR.

  20. Isolation of xanthyletin, an inhibitor of ants' symbiotic fungus, by high-speed counter-current chromatography.

    Science.gov (United States)

    Cazal, Cristiane de Melo; Domingues, Vanessa de Cássia; Batalhão, Jaqueline Raquel; Bueno, Odair Corrêa; Filho, Edson Rodrigues; da Silva, Maria Fátima G Fernandes; Vieira, Paulo Cezar; Fernandes, João Batista

    2009-05-08

    Xanthyletin, an inhibitor of symbiotic fungus (Leucoagaricus gongylophorus) of leaf-cutting ant (Atta sexdens rubropilosa), as well as suberosin, seselin and xanthoxyletin were isolated from Citrus sinensis grafted on Citrus limonia. A two-phase solvent system composed of hexane/ethanol/acetonitrile/water (10:8:1:1, v/v) was used for the high-speed counter-current chromatographic isolation of xanthyletin with high yield and over 99% purity as determined by liquid and gas chromatography with mass spectrometry detection. Identifications were performed by UV spectra, IR spectra, (1)H NMR and (13)C NMR.

  1. Separation of anthraquinone compounds from the seed of Cassia obtusifolia L. using recycling counter-current chromatography.

    Science.gov (United States)

    Yang, Jianhong; Ye, Haoyu; Lai, Huijun; Li, Shucai; He, Shichao; Zhong, Shijie; Chen, Lijuan; Peng, Aihua

    2012-01-01

    Recycling counter-current chromatography (CCC) together with step-gradient CCC and medium-pressure liquid chromatography (MPLC) was employed to separate nine anthraquinone compounds from Cassia obtusifolia L. in this study. The results showed that recycling CCC is a powerful tool for compounds that are difficult to separate with common elution mode. CCC was the better option for crude material while MPLC had advantage for the final tuning. The combination of recycling CCC and MPLC could simplify the method exploring process in the separation process. The structures of these compounds were identified according to their mass spectra, by (1)H-NMR and compared with standard compounds.

  2. Determination of Alternaria mycotoxins in wine and juice using ionic liquid modified countercurrent chromatography as a pretreatment method followed by high-performance liquid chromatography.

    Science.gov (United States)

    Fan, Chen; Cao, Xueli; Liu, Man; Wang, Wei

    2016-03-04

    Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants in food materials. The objective of this study was to develop a pretreatment method with countercurrent chromatography (CCC) for enrichment and cleanup of trace Alternaria mycotoxins in food samples prior to high-performance liquid chromatography (HPLC) analysis. An Analytical CCC instrument with a column volume 22.5mL was used, and a two-phase solvent system composed of ethyl acetate and water modified with 6% [HOOMIM][Cl] in mass to volume ratio was selected. Under the optimized CCC operation conditions, trace amounts of AOH, AME, and TeA in large volume of liquid sample were efficiently extracted and enriched in the stationary phase, and then eluted out just by reversing the stationary phase as mobile phase in the opposite flowing direction tail-to-head. The enrichment and elution strategies are unique and can be fulfilled online with high enrichment factors (87-114) and high recoveries (81.14-110.94%). The method has been successively applied to the determination of Alternaria mycotoxins in real apple juice and wine samples with the limits of detection (LOD) in the range of 0.03-0.14μgL(-1). Totally 12 wine samples and 15 apple juice samples from the local market were analyzed. The detection rate of AOH and AME in both kinds of the samples were more than 50%, while TeA was found in relatively high level of 1.75-49.61μgL(-1) in some of the apple juice samples. The proposed method is simple, rapid, and sensitive and could also be used for the analysis and monitoring of Alternaria mycotoxin in other food samples.

  3. X-ray CT-Derived Soil Characteristics Explain Varying Air, Water, and Solute Transport Properties across a Loamy Field

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per;

    2016-01-01

    The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... be factors that increased the uncertainty of the relationships. Nevertheless, the results confirmed the potential of X-ray CT visualization techniques for estimating fluxes through soil at the field scale....... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with measurements...

  4. Synthesis of a Two-Dimensional Covalent Organic Monolayer through Dynamic Imine Chemistry at the Air/Water Interface.

    Science.gov (United States)

    Dai, Wenyang; Shao, Feng; Szczerbiński, Jacek; McCaffrey, Ryan; Zenobi, Renato; Jin, Yinghua; Schlüter, A Dieter; Zhang, Wei

    2016-01-01

    A two-dimensional covalent organic monolayer was synthesized from simple aromatic triamine and dialdehyde building blocks by dynamic imine chemistry at the air/water interface (Langmuir-Blodgett method). The obtained monolayer was characterized by optical microscopy, scanning electron microscopy, and atomic force microscopy, which unambiguously confirmed the formation of a large (millimeter range), unimolecularly thin aromatic polyimine sheet. The imine-linked chemical structure of the obtained monolayer was characterized by tip-enhanced Raman spectroscopy, and the peak assignment was supported by spectra simulated by density functional theory. Given the modular nature and broad substrate scope of imine formation, the work reported herein opens up many new possibilities for the synthesis of customizable 2D polymers and systematic studies of their structure-property relationships.

  5. Influence of current velocity and wind speed on air-water gas exchange in a mangrove estuary

    Science.gov (United States)

    Ho, David T.; Coffineau, Nathalie; Hickman, Benjamin; Chow, Nicholas; Koffman, Tobias; Schlosser, Peter

    2016-04-01

    Knowledge of air-water gas transfer velocities and water residence times is necessary to study the fate of mangrove derived carbon exported into surrounding estuaries and ultimately to determine carbon balances in mangrove ecosystems. For the first time, the 3He/SF6 dual tracer technique, which has been proven to be a powerful tool to determine gas transfer velocities in the ocean, is applied to Shark River, an estuary situated in the largest contiguous mangrove forest in North America. The mean gas transfer velocity was 3.3 ± 0.2 cm h-1 during the experiment, with a water residence time of 16.5 ± 2.0 days. We propose a gas exchange parameterization that takes into account the major sources of turbulence in the estuary (i.e., bottom generated shear and wind stress).

  6. Supramolecular 1-D polymerization of DNA origami through a dynamic process at the 2-dimensionally confined air-water interface.

    Science.gov (United States)

    Yonamine, Yusuke; Cervantes-Salguero, Keitel; Minami, Kosuke; Kawamata, Ibuki; Nakanishi, Waka; Hill, Jonathan P; Murata, Satoshi; Ariga, Katsuhiko

    2016-05-14

    In this study, a Langmuir-Blodgett (LB) system has been utilized for the regulation of polymerization of a DNA origami structure at the air-water interface as a two-dimensionally confined medium, which enables dynamic condensation of DNA origami units through variation of the film area at the macroscopic level (ca. 10-100 cm(2)). DNA origami sheets were conjugated with a cationic lipid (dioctadecyldimethylammonium bromide, 2C18N(+)) by electrostatic interaction and the corresponding LB-film was prepared. By applying dynamic pressure variation through compression-expansion processes, the lipid-modified DNA origami sheets underwent anisotropic polymerization forming a one-dimensionally assembled belt-shaped structure of a high aspect ratio although the thickness of the polymerized DNA origami was maintained at the unimolecular level. This approach opens up a new field of mechanical induction of the self-assembly of DNA origami structures.

  7. Countercurrent chromatographic with upright multilayer coil plante centrifuge for large-scale preparation%一种用于大容量逆流色谱制备的立式多层螺旋管行星式离心机

    Institute of Scientific and Technical Information of China (English)

    吴世华; 孙翠荣; 戴元柏; 周慧; 潘远江; 张虹

    2003-01-01

    Owing to no complications caused by solid supports, such as adsorptive sample loss and deactivation, tailing of solute peaks, and contamination, countercurrent chromatography (CCC) has been an area of intense research since the first introduction of CCC in 1970,[1] and various apparatus and broad applications have been advanced[2,3]. For these developments, the type-J synchronous planet centrifuge has received considerable attention, which relies not only on its relatively simple mechanic design, but also on its high partition efficiency and short elution time caused by mixing and settling for the efficient chromatographic separations. In the past, however, almost all of type-J centrifuges rotated slowly were disposed horizontally due to the original design and some experiments that gravis plays an important role at a low rotary speed as similar to type-V rotating multilayer helical tube in unit gravity[4-9]. In fact,we discovered that the upright apparatus holds more retention of stationary phase than the horiziontal aparatus when large standard tubings were used as mutilayer coil column and the aparatus was operated under same contions. We report here a new coil planet centrifuge with four upright cylindrical columns for large scale countercurrent chromatographic preparation. The design principle and apparatus of UCCC is as samilar to type-J multilayer coil planet centrifuge. Four uptight cylindrical column holders are symmetrically arranged around the centrifuge axis as similar to the type-J HSCCC with three horizontal multilayer coils connected in series[8] . A series of experiments indicat that upright CCC has many advantages over the horizontal CCC when using a large-bore tube as multilayer coil column for large scale countercurrent chromatographic separation.Upright CCC provide a versatile countercurrent chromatographic method for large-scale preparation from very crude sample. It has good preparative capacity and flexible suitability to various sample and

  8. Distribution ratio, distribution constant and partition coefficient. Countercurrent chromatography retention of benzoic acid.

    Science.gov (United States)

    Berthod, Alain; Mekaoui, Nazim

    2011-09-09

    There is some confusion in chromatography between terms such as solute distribution ratio, distribution constant and partition coefficient. These terms are very precisely defined in the field of liquid-liquid systems and liquid-liquid extraction as well as in the field of chromatography with sometimes conflicting definitions. Countercurrent chromatography (CCC) is a chromatographic technique in which the stationary phase is a support-free liquid. Since the mobile phase is also liquid, biphasic liquid systems are used. This work focuses on the exact meaning of the terms since there are consequences on experimental results. The retention volumes of solutes in CCC are linearly related to their distribution ratios. The partition coefficient that should be termed (IUPAC recommendation) distribution constant is linked to a single definite species. Using benzoic acid that can dimerize in heptane and ionize in aqueous phase and an 18 mL hydrodynamic CCC column, the role and relationships between parameters and the consequences on experimental peak position and shape are discussed. If the heptane/water distribution constant (marginally accepted to be called partition coefficient) of benzoic acid is 0.2 at 20 °C and can be tabulated in books, its CCC measured distribution ratio or distribution coefficient can change between zero (basic aqueous mobile phase) and more than 25 (acidic aqueous mobile phase and elevated concentration). Benzoic acid distribution ratio and partition coefficient coincide only when both dimerization and ionization are quenched, i.e. at very low concentration and pH 2. It is possible to quench dimerization adding butanol in the heptane/water system. However, butanol additions also affect the partition coefficient of benzoic acid greatly by increasing it.

  9. Design of Countercurrent Separation of Ginkgo biloba Terpene Lactones by Nuclear Magnetic Resonance

    Science.gov (United States)

    Qiu, Feng; Friesen, Brent J.; McAlpine, James B.; Pauli, Guido F.

    2012-01-01

    Terpene lactones such as bilobalide, ginkgolides A, B, C, and J are major bioactive compounds of Ginkgo biloba L. Purification of these compounds is tedious due to their similar chemical properties. For the purpose of developing an effective and efficient method for both analytical and preparative separation of terpene lactones in G. biloba, an innovative orthogonality-enhanced high-speed countercurrent chromatography (HSCCC) method was established. Taking advantage of quantitative 1H NMR (qHNMR) methodology, partition coefficients (K) of individual terpene lactones were calculated directly from crude G. biloba leaf extract, using their H-12 signals as distinguishing feature. The partitioning experiment assisted the design of a two dimensional (2D) HSCCC procedure using a pair of orthogonal HSCCC solvent systems (SSs), ChMWat +4 and HEMSoWat +3/0.05%. It was surprising that the resolution of ginkgolides A and B was improved by 25% in the HEMWat +3 SS modified with 0.5% DMSO. Consequently, all five terpene lactones could be well separated with qHNMR purity > 95% from G. biloba leaf extract. The separation was further evaluated by offline qHNMR analysis of HSCCC fractions associated with Gaussian curve fitting. The results showed less than 2% error in HSCCC retention predicted from the partitioning experiment. This compelling consistency demonstrates that qHNMR-derived K determination (“K-by-NMR”) can be used to predict CCC fractionation and target purification of analytes from complex mixtures. Furthermore, Gaussian curve fitting enabled an accurate prediction of less than 2% impurity in the CCC fraction, which demonstrates its potential as a powerful tool to study the presence of minor constituents, especially when they are beyond the detection limit of conventional spectroscopic detectors. PMID:22579361

  10. Gas exchange rates across the sediment-water and air-water interfaces in south San Francisco Bay

    Science.gov (United States)

    Hartman, Blayne; Hammond, Douglas E.

    1984-01-01

    Radon 222 concentrations in the water and sedimentary columns and radon exchange rates across the sediment-water and air-water interfaces have been measured in a section of south San Francisco Bay. Two independent methods have been used to determine sediment-water exchange rates, and the annual averages of these methods agree within the uncertainty of the determinations, about 20%. The annual average of benthic fluxes from shoal areas is nearly a factor of 2 greater than fluxes from the channel areas. Fluxes from the shoal and channel areas exceed those expected from simple molecular diffusion by factors of 4 and 2, respectively, apparently due to macrofaunal irrigation. Values of the gas transfer coefficient for radon exchange across the air-water interface were determined by constructing a radon mass balance for the water column and by direct measurement using floating chambers. The chamber method appears to yield results which are too high. Transfer coefficients computed using the mass balance method range from 0.4 m/day to 1.8 m/day, with a 6-year average of 1.0 m/day. Gas exchange is linearly dependent upon wind speed over a wind speed range of 3.2–6.4 m/s, but shows no dependence upon current velocity. Gas transfer coefficients predicted from an empirical relationship between gas exchange rates and wind speed observed in lakes and the oceans are within 30% of the coefficients determined from the radon mass balance and are considerably more accurate than coefficients predicted from theoretical gas exchange models.

  11. Kinetics of adsorption of whey proteins and hydroxypropyl-methyl-cellulose mixtures at the air-water interface.

    Science.gov (United States)

    Pérez, Oscar E; Carrera Sánchez, Cecilio; Pilosof, Ana M R; Rodríguez Patino, Juan M

    2009-08-15

    The aim of this research is to quantify the competitive adsorption of a whey protein concentrate (WPC) and hydroxypropyl-methyl-cellulose (HPMC so called E4M, E50LV and F4M) at the air-water interface by means of dynamic surface tensiometry and Brewster angle microscopy (BAM). These biopolymers are often used together in many food applications. The concentration of both protein and HPMC, and the WPC/HPMC ratio in the aqueous bulk phase were variables, while pH (7), the ionic strength (0.05 M) and temperature (20 degrees C) were kept constant. The differences observed between mixed systems were in accordance with the relative bulk concentration of these biopolymers (C(HPMC) and C(WPC)) and the molecular structure of HPMC. At short adsorption times, the results show that under conditions where both WPC and HPMC could saturate the air-water interface on their own or when C(HPMC) > or = C(WPC), the polysaccharide dominates the surface. At concentrations where none of the biopolymers was able to saturate the interface, a synergistic behavior was observed for HPMC with lower surface activity (E50LV and F4M), while a competitive adsorption was observed for E4M (the HPMC with the highest surface activity). At long-term adsorption the rate of penetration controls the adsorption of mixed components. The results reflect complex competitive/synergistic phenomena under conditions of thermodynamic compatibility or in the presence of a "depletion mechanism". Finally, the order in which the different components reach the interface will influence the surface composition and the film properties.

  12. Reactivity of aldehydes at the air-water interface. Insights from molecular dynamics simulations and ab initio calculations.

    Science.gov (United States)

    Martins-Costa, Marilia T C; García-Prieto, Francisco F; Ruiz-López, Manuel F

    2015-02-14

    Understanding the influence of solute-solvent interactions on chemical reactivity has been a subject of intense research in the last few decades. Theoretical studies have focused on bulk solvation phenomena and a variety of models and methods have been developed that are now widely used by both theoreticians and experimentalists. Much less attention has been paid, however, to processes that occur at liquid interfaces despite the important role such interfaces play in chemistry and biology. In this study, we have carried out sequential molecular dynamics simulations and quantum mechanical calculations to analyse the influence of the air-water interface on the reactivity of formaldehyde, acetaldehyde and benzaldehyde, three simple aldehydes of atmospheric interest. The calculated free-energy profiles exhibit a minimum at the interface, where the average reactivity indices may display large solvation effects. The study emphasizes the role of solvation dynamics, which are responsible for large fluctuations of some molecular properties. We also show that the photolysis rate constant of benzaldehyde in the range 290-308 nm increases by one order of magnitude at the surface of a water droplet, from 2.7 × 10(-5) s(-1) in the gas phase to 2.8 × 10(-4) s(-1) at the air-water interface, and we discuss the potential impact of this result on the chemistry of the troposphere. Experimental data in this domain are still scarce and computer simulations like those presented in this work may provide some insights that can be useful to design new experiments.

  13. Air-water greenhouse gases exchange in two coastal systems in Cadiz Bay (SW Spain)

    Science.gov (United States)

    Burgos, Macarena; Ortega, Teodora; Forja, Jesús

    2014-05-01

    Coastal areas are subject to a great anthropogenic pressure because more than half of the world's population lives in its vicinity, causing organic matter inputs, which intensifies greenhouse gas emissions into the atmosphere. Water surface greenhouse gas concentrations (CH4 and N2O) have been estimated in two aquatic systems of Cadiz Bay Natural Park: Rio San Pedro Creek and Sancti Petri Channel Water renewal in Rio San Pedro Creek is tidally controlled. Due to its little freshwater input, the Creek is essentially a marine system. Several fish farms are distributed on its banks discharging effluents without previous treatment. Nine sampling stations are distributed along this system 12 Km length. Sancti Petri Channel is a flow channel-ebb tides extending from the inner Cadiz Bay to the Atlantic Ocean along 17 Km. Organic matter pollution sources in this environment are straggly. There exist anthropogenic inputs such as aquaculture effluents and sewage discharges coming through the Iro River, which flows into the Channel central part. In addition there are natural organic matter inputs from surrounding marshes. It has been established 11 sampling stations crossing this system. Sampling was conducted seasonally during 2013. CH4 and N2O concentrations were obtained though a gas chromatograph connected to an equilibration system. Greenhouse gas values vary between 24 and 295 nM and 16 and 27 nM for CH4 and N2O, respectively. Gas concentrations increase close to the fish farm effluent in Rio San Pedro Creek, and next to Iro River's mouth in Sancti Petri tidal Channel. Both environments act as greenhouse gas sources into the atmosphere, showing seasonal variations. It has been estimated mean fluxes of 75.3 μmol m-2 d-1 of CH4 and 31.9 μmol m-2 d-1 of N2O for both systems.

  14. Preparative Isolation of Seven Diterpenoid Alkaloids from Aconitum coreanum by pH-Zone-Refining Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Xueyong Wang

    2014-08-01

    Full Text Available The aim of this paper was to seek an efficient method to preparative separation of alkaloid compounds from Aconitum coreanum (Guanbaifu, a well-known traditional Chinese medicinal plant for heart disease. Seven alkaloid compounds were successfully purified by pH-zone-refining counter-current chromatography with two-phase solvent system of petroleum ether–ethyl acetate–methanol–water (5:5:1:9, v/v/v/v, 10 mM triethylamine in upper phase and 10 mM hydrochloric acid in lower phase. From 3.5 g of crude extract, 356 mg of Guanfu base I, 578 mg of Guanfu base A, 74 mg of atisine, 94 mg of Guanfu base F, 423 mg of Guanfu base G, 67 mg of Guanfu base R and 154 mg of Guanfu base P were obtained with the purity of 96.40%, 97.2%, 97.5%, 98.1%, 98.9%, 98.3% and 98.4%. Their chemical structures were identified by TOF-MS and 1H-NMR. This study indicated that pH-zone-refining counter-current chromatography was an efficient method for separating the kind of alkaloids with low absorbance values.

  15. Isolation and purification of arctigenin from Fructus Arctii by enzymatic hydrolysis combined with high-speed counter-current chromatography.

    Science.gov (United States)

    Liu, Feng; Xi, Xingjun; Wang, Mei; Fan, Li; Geng, Yanling; Wang, Xiao

    2014-02-01

    Enzymatic hydrolysis pretreatment combined with high-speed counter-current chromatography for the transformation and isolation of arctigenin from Fructus Arctii was successfully developed. In the first step, the extract solution of Fructus Arctii was enzymatic hydrolyzed by β-glucosidase. The optimal hydrolysis conditions were 40°C, pH 5.0, 24 h of hydrolysis time, and 1.25 mg/mL β-glucosidase concentration. Under these conditions, the content of arctigenin was transformed from 2.60 to 12.59 mg/g. In the second step, arctigenin in the hydrolysis products was separated and purified by high-speed counter-current chromatography with a two-phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (10:25:15:20, v/v), and the fraction was analyzed by HPLC, ESI-MS, and (1)H NMR spectroscopy. Finally, 102 mg of arctigenin with a purity of 98.9% was obtained in a one-step separation from 200 mg of hydrolyzed sample.

  16. Modeling and simulation of nanoparticles transport in a two-phase flow in porous media

    KAUST Repository

    El-Amin, Mohamed

    2012-01-01

    In the current paper, a mathematical model to describe the nanoparticles transport carried by a two-phase flow in a porous medium is presented. Both capillary forces as well as Brownian diffusion are considered in the model. A numerical example of countercurrent water-oil imbibition is considered. We monitor the changing of the fluid and solid properties due to the addition of the nanoparticles using numerical experiments. Variation of water saturation, nanoparticles concentration and porosity ratio are investigated.

  17. SIMULATION OF NON-AZEOTROPIC REFRIGERANT MIXTURES FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER WITH COUNTERCURRENT HEAT EXCHANGES

    Science.gov (United States)

    The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. This RF is housed in a stan...

  18. From selective tidal transport to counter-current swimming during watershed colonisation: an impossible step for young-of-the-year catadromous fish?

    Directory of Open Access Journals (Sweden)

    Trancart T.

    2014-01-01

    Full Text Available During watershed colonisation by catadromous species, two main phases have been identified: tidal estuary crossing and non-tidal river colonisation. Fishes use selective tidal-stream transport (STST during the first phase of this colonisation, and counter-current swimming during the second phase. Therefore, catadromous species have to achieve a behavioural shift, from STST to constant counter-current swimming. This has not yet been observed, and the location and period of this shift is still unknown. Our experimental protocol aimed to mimic the spatial progression of crossing the tidal limit within a 3-week experiment. Two catadromous fishes, thinlip mullets and European eels, were initially subjected to current reversal every 6.2 h during the first week. A gradual tidal distortion was performed during the second week, and fishes were submitted to a unidirectional water current during the third week. Our results reveal that all catadromous species use STST as far as possible within the tidal limit. At this point, in this experimental study, no young-of-the-year (YOY fishes shifted from STST to constant counter-current swimming. This confirms that the behavioural shift occurs later, and that the second part of the upstream migration, counter-current progression, is performed by larger, older fishes and not YOY fishes.

  19. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    Energy Technology Data Exchange (ETDEWEB)

    Yortsos, Yanis C.

    2002-10-08

    In this report, the thrust areas include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  20. Isolamento do alcalóide ricinina das folhas de Ricinus communis (Euphorbiaceae através de cromatografias em contracorrente Isolation of the alkaloid ricinine from the leaves of Ricinus communis (Euphorbiaceae through counter-current chromatography

    Directory of Open Access Journals (Sweden)

    Ana Cristina Leite

    2005-12-01

    Full Text Available Droplet counter-current chromatography, rotation locular counter-current chromatography and high-speed counter-current chromatography were applied to the preparative separation of the alkaloid ricinine from the dichloromethane extracts of Ricinus communis leaves. The solvent system used was composed of dichloromethane-methanol-water (93:35:72 v/v/v and all techniques led to the isolation of large amounts of the alkaloid. The best result was obtained through HSCCC, since the ricinine yield was respectively 50% and 30% higher than when using RLCCC or DCCC.

  1. Experimental Study of the APR+ Direct ECC Bypass in the Air-water Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kihwan; Choi, Hae-Seob; Park, Kil-won; Kwon, Tae-Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The APR+ is an improved Korean Nuclear Power Reactor, which has been developed as a two loop evolutionary PWR (Pressure Water Reactor) with a number of advanced design features to enhance safety based on the APR-1400 technology. The emergency core cooling system (ECC) of the APR+ is different with that of the APR-1400, though the APR+ adopted a direct vessel injection (DVI) system which is the same design features of the APR-14000. The main difference of the DVI+ is the emergency core barrel duct (ECBD) which is designed to increase the amount of the injection water to the core region. The performance of the DVI system has been an important issues for past decades, and many researchers have studied the related thermal-hydraulic technical issues such as the ECC bypass fraction, the steam condensation effect, temperature distribution, sub-cooling margin, and etc. However, the previous research cannot be directly applicable to the APR+ owing to the unique features of the DVI+. The current study will elaborate on the experimental evaluation of the direct ECC bypass performance. The 1/5 ECC bypass test facility which is designed with a linearly reduced 1/5 scale referring to the APR+ was used to investigate the effect of the DVI+ injection nozzle location and the broken cold leg velocity on the direct ECC bypass fraction. However, air is used as a working fluid to simulate the steam flow induced from the broken cold leg, and thus, the direct contact condensation effect is not considered in this study. Experimental study for the direct ECC bypass phenomena has been carryout out with various the injection mode and air velocity conditions. The tests were performed in the 1/5 scale ECC bypass test facility, and the test condition was defined using a scaling law referring to the APR+ reactor. Test results showed that the direct ECC bypass fraction was greatly enhanced compared with the reference test (w/o ECBD)

  2. Simulating the Vapour Phase Air/Water Exchange of p,p′-DDE, p,p′-DDT, Lindane, and 2,3,7,8-Tetrachlorodibenzodioxin

    Science.gov (United States)

    Uncertainties in our understanding of gaseous air/water exchange have emerged as major sources of concern in efforts to construct global and regional mass balances of both the green house gas carbon dioxide and semi-volatile persistent, bioaccumulative and toxic chemicals. Hoff e...

  3. Modulation of the adsorption properties at air-water interfaces of complexes of egg white ovalbumin with pectin by the dielectric constant

    NARCIS (Netherlands)

    Kudryashova, E.V.; Jongh, H.H.J.de

    2008-01-01

    The possibility of modulating the mesoscopic properties of food colloidal systems by the dielectric constant is studied by determining the impact of small amounts of ethanol (10%) on the adsorption of egg white ovalbumin onto the air-water interface in the absence and presence of pectin. The adsorpt

  4. The adsorption and unfolding kinetics determines the folding state of proteins at the air-water interface and thereby the equation of state

    NARCIS (Netherlands)

    Wierenga, P.A.; Egmond, M.R.; Voragen, A.G.J.; Jongh, H.H.J.de

    2006-01-01

    Unfolding of proteins has often been mentioned as an important factor during the adsorption process at air-water interfaces and in the increase of surface pressure at later stages of the adsorption process. This work focuses on the question whether the folding state of the adsorbed protein depends o

  5. Hydrophobic recovery of repeatedly plasma-treated silicone rubber .2. A comparison of the hydrophobic recovery in air, water, or liquid nitrogen

    NARCIS (Netherlands)

    Everaert, EP; VanderMei, HC; Busscher, HJ

    1996-01-01

    Surfaces of medical grade silicone rubber (Q7-4750, Dow Coming) were modified by repeated (six times) RF plasma treatments using various discharge gases: oxygen, argon, carbon dioxide, and ammonia. The treated samples were stored for a period of 3 months in ambient air, water, or liquid nitrogen. Su

  6. pH effects on the molecular structure of β-lactoglobulin modified air-water interfaces and its impact on foam rheology.

    Science.gov (United States)

    Engelhardt, Kathrin; Lexis, Meike; Gochev, Georgi; Konnerth, Christoph; Miller, Reinhard; Willenbacher, Norbert; Peukert, Wolfgang; Braunschweig, Björn

    2013-09-17

    Macroscopic properties of aqueous β-lactoglobulin (BLG) foams and the molecular properties of BLG modified air-water interfaces as their major structural element were investigated with a unique combination of foam rheology measurements and interfacial sensitive methods such as sum-frequency generation and interfacial dilatational rheology. The molecular structure and protein-protein interactions at the air-water interface can be changed substantially with the solution pH and result in major changes in interfacial dilational and foam rheology. At a pH near the interfacial isoelectric point BLG molecules carry zero net charge and disordered multilayers with the highest interfacial dilatational elasticity are formed at the air-water interface. Increasing or decreasing the pH with respect to the isoelectric point leads to the formation of a BLG monolayer with repulsive electrostatic interactions among the adsorbed molecules which decrease the interfacial dilational elasticity. The latter molecular information does explain the behavior of BLG foams in our rheological studies, where in fact the highest apparent yield stresses and storage moduli are established with foams from electrolyte solutions with a pH close to the isoelectric point of BLG. At this pH the gas bubbles of the foam are stabilized by BLG multilayers with attractive intermolecular interactions at the ubiquitous air-water interfaces, while BLG layers with repulsive interactions decrease the apparent yield stress and storage moduli as stabilization of gas bubbles with a monolayer of BLG is less effective.

  7. 多级逆流微萃取系统开发与传质性能研究%Development and Mass Transfer Performance of a Multi-stage Countercurrent Micro-extraction System

    Institute of Scientific and Technical Information of China (English)

    罗强; 李少伟; 郭绪强; 景山

    2014-01-01

    The purpose of this work is to develop a multi-stage countercurrent micro-extraction system to achieve stable operation of countercurrent flow, and investigate liquid-liquid mass transfer performance. The countercurrent flow was achieved by using a pulse feeding discharging system and a one-way control system. The pulse feeding discharging system was composed of a reciprocating pump with four pistons moving at opposite directions, and four chambers connected with the material vessels by check valves. The single-stage extraction performance was first investigated in a multi-channel micro-extraction device with 30%TBP-kerosene / water- nitric acid as the liquid-liquid extraction system. The effect of operation conditions including pulse frequency, pulse volume and concentration on the mass transfer performance was investigated, and then the extraction performance of the four-stage micro-extraction system was tested. Optimal operation conditions were finally obtained. The highest extraction efficiency of the single-stage extraction is achieved when the pulse frequency is at 0.13Hz, with the pulse stroke of both phases at 80µL. The total extraction efficiency of the four-stage micro-extraction system is higher than 90%in all experiments.%为开发多级逆流微萃取系统,实现稳定逆流操作,研究液-液两相在此系统中的传质规律,以及探索传质性能的最优化操作条件。以双向四缸往复泵和四个缓冲室通过单向阀与料液罐相连,构成脉冲进料出料系统,以单向阀控制两相单向流动,实现微萃取系统的逆流操作;以30%(v/v)TBP-煤油/水体系为研究对象,选择硝酸为待萃取物,以平行并列微通道为微萃取设备,进行单级微萃取实验,研究脉冲频率、脉冲体积、浓度等操作条件对传质性能的影响;在此基础上,进行四级逆流微萃取的研究,总结出最优化操作条件。结果表明,在两相脉冲冲程均为80µ

  8. Atmospheric emissions from the Deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate

    Science.gov (United States)

    Ryerson, T. B.; Aikin, K. C.; Angevine, W. M.; Atlas, E. L.; Blake, D. R.; Brock, C. A.; Fehsenfeld, F. C.; Gao, R.-S.; de Gouw, J. A.; Fahey, D. W.; Holloway, J. S.; Lack, D. A.; Lueb, R. A.; Meinardi, S.; Middlebrook, A. M.; Murphy, D. M.; Neuman, J. A.; Nowak, J. B.; Parrish, D. D.; Peischl, J.; Perring, A. E.; Pollack, I. B.; Ravishankara, A. R.; Roberts, J. M.; Schwarz, J. P.; Spackman, J. R.; Stark, H.; Warneke, C.; Watts, L. A.

    2011-04-01

    The fate of deepwater releases of gas and oil mixtures is initially determined by solubility and volatility of individual hydrocarbon species; these attributes determine partitioning between air and water. Quantifying this partitioning is necessary to constrain simulations of gas and oil transport, to predict marine bioavailability of different fractions of the gas-oil mixture, and to develop a comprehensive picture of the fate of leaked hydrocarbons in the marine environment. Analysis of airborne atmospheric data shows massive amounts (˜258,000 kg/day) of hydrocarbons evaporating promptly from the Deepwater Horizon spill; these data collected during two research flights constrain air-water partitioning, thus bioavailability and fate, of the leaked fluid. This analysis quantifies the fraction of surfacing hydrocarbons that dissolves in the water column (˜33% by mass), the fraction that does not dissolve, and the fraction that evaporates promptly after surfacing (˜14% by mass). We do not quantify the leaked fraction lacking a surface expression; therefore, calculation of atmospheric mass fluxes provides a lower limit to the total hydrocarbon leak rate of 32,600 to 47,700 barrels of fluid per day, depending on reservoir fluid composition information. This study demonstrates a new approach for rapid-response airborne assessment of future oil spills.

  9. Effects of surface pressure on the properties of Langmuir monolayers and interfacial water at the air-water interface.

    Science.gov (United States)

    Lin, Wei; Clark, Anthony J; Paesani, Francesco

    2015-02-24

    The effects of surface pressure on the physical properties of Langmuir monolayers of palmitic acid (PA) and dipalmitoylphosphatidic acid (DPPA) at the air/water interface are investigated through molecular dynamics simulations with atomistic force fields. The structure and dynamics of both monolayers and interfacial water are compared across the range of surface pressures at which stable monolayers can form. For PA monolayers at T = 300 K, the untilted condensed phase with a hexagonal lattice structure is found at high surface pressure, while the uniformly tilted condensed phase with a centered rectangular lattice structure is observed at low surface pressure, in agreement with the available experimental data. A state with uniform chain tilt but no periodic spatial ordering is observed for DPPA monolayers on a Na(+)/water subphase at both high and low surface pressures. The hydrophobic acyl chains of both monolayers pack efficiently at all surface pressures, resulting in a very small number of gauche defects. The analysis of the hydrogen-bonding structure/dynamics at the monolayer/water interface indicates that water molecules hydrogen-bonded to the DPPA head groups reorient more slowly than those hydrogen-bonded to the PA head groups, with the orientational dynamics becoming significantly slower at high surface pressure. Possible implications for physicochemical processes taking place on marine aerosols in the atmosphere are discussed.

  10. Langmuir and Langmuir-Blodgett films of capsules of haemoglobin at air/water and solid/air interfaces

    Indian Academy of Sciences (India)

    J Maheshkumar; A Dhathathreyan

    2013-03-01

    Organized assemblies of capsules of haemoglobin (Hb), in the size range of 0.1 to 0.3 in Langmuir films have been studied at air/water interface below and above the isoelectric point. Spread films of these organizates suggest that there is no expulsion of individual particles or particle assemblies at the interface and the particles are stable. Dynamic surface tension and the associated dilational and shear visco-elasticity in these films suggest that the capsules are highly elastic. Multilayer films of the capsules using Langmuir-Blodgett technique have been fabricated by sequential deposition on solid surfaces. These films have been characterized by circular dichroism spectroscopy (CD), atomic force microscopy (AFM), quartz crystal microbalance (QCM) and Fourier transform infrared with reflection absorption spectroscopy (FTIR-RAS). No appreciable change in the secondary structural features of Hb is seen from CD studies indicating the stability of the protein in these organized assemblies. Sizes of these capsules change near the isoelectric point and large swollen multiwalled capsules are formed. The elastic films of capsules of Hb provide a useful post preparation approach for modification of the surface roughness, porosity, and permeability of pre-assembled polypeptide microcapsules.

  11. Effect of surfactants on surface activity and rheological properties of type I collagen at air/water interface.

    Science.gov (United States)

    Kezwoń, Aleksandra; Góral, Ilona; Frączyk, Tomasz; Wojciechowski, Kamil

    2016-12-01

    We describe the effect of three synthetic surfactants (anionic - sodium dodecyl sulfate (SDS), cationic - cetyltrimethylammonium bromide (CTAB) and nonionic - Triton X-100 (TX-100)) on surface properties of the type I calf skin collagen at the air/water interface in acidic solutions (pH 1.8). The protein concentration was fixed at 5×10(-6)molL(-1) and the surfactant concentration was varied in the range 5×10(-6)molL(-1)-1×10(-4)molL(-1), producing the protein/surfactant mixtures with molar ratios of 1:1, 1:2, 1:5, 1:10 and 1:20. An Axisymmetric Drop Shape Analysis (ADSA) method was used to determine the dynamic surface tension and surface dilatational moduli of the mixed adsorption layers. Two spectroscopic techniques: UV-vis spectroscopy and fluorimetry allowed us to determine the effect of the surfactants on the protein structure. The thermodynamic characteristic of the mixtures was studied using isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). Modification of the collagen structure by SDS at low surfactant/protein ratios has a positive effect on the mixture's surface activity with only minor deterioration of the rheological properties of the adsorbed layers. The collagen/CTAB mixtures do not show that pronounced improvement in surface activity, while rheological properties are significantly deteriorated. The mixtures with non-ionic TX-100 do not show any synergistic effects in surface activity.

  12. Impact of biogenic amine molecular weight and structure on surfactant adsorption at the air-water interface.

    Science.gov (United States)

    Penfold, Jeffrey; Thomas, Robert K; Li, Peixun

    2016-02-01

    The oligoamines, such as ethylenediamine to pentaethylenetetramine, and the aliphatic biogenic amines, such as putrescine, spermidine and spermine, strongly interact with anionic surfactants, such as sodium dodecylsulfate, SDS. It has been shown that this results in pronounced surfactant adsorption at the air-water interface and the transition from monolayer to multilayer adsorption which depends upon solution pH and oligoamine structure. In the neutron reflectivity, NR, and surface tension, ST, results presented here the role of the oligoamine structure on the adsorption of SDS is investigated more fully using a range of different biogenic amines. The effect of the extent of the intra-molecular spacing between amine groups on the adsorption has been extended by comparing results for cadavarine with putrescine and ethylenediamine. The impact of more complex biogenic amine structures on the adsorption has been investigated with the aromatic phenethylamine, and the heterocyclic amines histamine and melamine. The results provide an important insight into how surfactant adsorption at interfaces can be manipulated by the addition of biogenic amines, and into the role of solution pH and oligoamine structure in modifying the interaction between the surfactant and oligoamine. The results impact greatly upon potential applications and in understanding some of the important biological functions of biogenic amines.

  13. Air-water partition coefficients for a suite of polycyclic aromatic and other C10 through C20 unsaturated hydrocarbons.

    Science.gov (United States)

    Rayne, Sierra; Forest, Kaya

    2016-09-18

    The air-water partition coefficients (Kaw) for 86 large polycyclic aromatic hydrocarbons and their unsaturated relatives were estimated using high-level G4(MP2) gas and aqueous phase calculations with the SMD, IEFPCM-UFF, and CPCM solvation models. An extensive method validation effort was undertaken which involved confirming that, via comparisons to experimental enthalpies of formation, gas-phase energies at the G4(MP2) level for the compounds of interest were at or near thermochemical accuracy. Investigations of the three solvation models using a range of neutral and ionic compounds suggested that while no clear preferential solvation model could be chosen in advance for accurate Kaw estimates of the target compounds, the employment of increasingly higher levels of theory would result in lower Kaw errors. Subsequent calculations on the polycyclic aromatic and unsaturated hydrocarbons at the G4(MP2) level revealed excellent agreement for the IEFPCM-UFF and CPCM models against limited available experimental data. The IEFPCM-UFF-G4(MP2) and CPCM-G4(MP2) solvation energy calculation approaches are anticipated to give Kaw estimates within typical experimental ranges, each having general Kaw errors of less than 0.5 log10 units. When applied to other large organic compounds, the method should allow development of a broad and reliable Kaw database for multimedia environmental modeling efforts on various contaminants.

  14. Characterization of atmospheric pressure plasma treated pure cashmere and wool/cashmere textiles: Treatment in air/water vapor mixture

    Energy Technology Data Exchange (ETDEWEB)

    Zanini, Stefano, E-mail: stefano.zanini@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Grimoldi, Elisa [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Citterio, Attilio [Politecnico di Milano, Dipartimento di Chimica, Materiali ed Ingegneria Chimica “G. Natta”, Via Mancinelli 7, I-20131 Milano (Italy); Riccardi, Claudia, E-mail: riccardi@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy)

    2015-09-15

    Highlights: • We treated cashmere and wool/cashmere textiles with atmospheric pressure plasma. • Wettability of the fabrics was increased. • The increment in wettability derived from a surface oxidation of the fibers. • Only minor etching effects were observed with scanning electron microscopy. - Abstract: We performed atmospheric pressure plasma treatments of pure cashmere and wool/cashmere textiles with a dielectric barrier discharge (DBD) in humid air (air/water vapor mixtures). Treatment parameters have been optimized in order to enhance the wettability of the fabrics without changing their bulk properties as well as their touch. A deep characterization has been performed to study the wettability, the surface morphologies, the chemical composition and the mechanical properties of the plasma treated textiles. The chemical properties of the plasma treated samples were investigated with attenuated total reflectance Fourier transform infrared (FTIR/ATR) spectroscopy and X-ray photoelectron microscopy (XPS). The analyses reveal a surface oxidation of the treated fabrics, which enhances their surface wettability. Morphological characterization of the treated fibers with scanning electron microscopy (SEM) reveals minor etching effects, an essential feature for the maintenance of the textile softness.

  15. Tuning the Structure and Rheology of Polystyrene Particles at the Air-Water Interface by Varying the pH.

    Science.gov (United States)

    Truzzolillo, Domenico; Sharaf, Hossameldeen; Jonas, Ulrich; Loppinet, Benoit; Vlassopoulos, Dimitris

    2016-07-12

    We form films of carboxylated polystyrene particles (C-PS) at the air-water interface and investigate the effect of subphase pH on their structure and rheology by using a suite of complementary experimental techniques. Our results suggest that electrostatic interactions drive the stability and the structural order of the films. In particular, we show that by increasing the pH of the subphase from 9 up to 13, the films exhibit a gradual transition from solid to liquidlike, which is accompanied by a loss of the long-range order (that characterizes them at lower values of pH). Direct optical visualization of the layers, scanning electron microscopy, and surface pressure isotherms indicate that the particles deposited at the interface form three-dimensional structures involving clusters, with the latter being suppressed and a quasi-2D particle configuration eventually reached at the highest pH values. Evidently, the properties of colloidal films can be tailored significantly by altering the pH of the subphase.

  16. Exchange of polycyclic aromatic hydrocarbons across the air-water interface in the Bohai and Yellow Seas

    Science.gov (United States)

    Chen, Yingjun; Lin, Tian; Tang, Jianhui; Xie, Zhiyong; Tian, Chongguo; Li, Jun; Zhang, Gan

    2016-09-01

    In this study, air and surface seawater samples collected from the Bohai (BS) and Yellow Seas (YS) in May 2012 were determined exchange of PAHs, especially of low-molecular-weight (LMW) PAHs (three- and four-ring PAHs) at the air-water interface. Net volatilization fluxes of LMW PAHs were 266-1454 ng/m2/d and decreased with distance from the coast, indicating that these PAHs transported from coastal runoff were potential contributors to the atmosphere in the BS and YS. Moreover, LMW PAHs were enriched in the dissolved phase compared with those in the particulate phase in the water column, possibly suggesting that the volatilized LMW PAHs were directly derived from wastewater discharge or petroleum pollution rather than released from contaminated sediments. The air-sea exchange fluxes of the three-ring PAHs were 2- to 20-fold higher than their atmospheric deposition fluxes in the BS and YS. The input to and output from the water reached equilibrium for four-ring PAHs. Differently, five- and six-ring PAHs were introduced into the marine environment primarily through dry and wet deposition, indicating that the water column was still a sink of these PAHs from the surrounding atmosphere.

  17. Preliminary Analysis on Heat Removal Capacity of Passive Air-Water Combined Cooling Heat Exchanger Using MARS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung-Sin; Jeon, Seong-Su; Hong, Soon-Joon [FNC Tech, Yongin (Korea, Republic of); Bae, Sung-Won; Kwon, Tae-Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Current design requirement for working time of PAFS heat exchanger is about 8 hours. Thus, it is not satisfied with the required cooling capability for the long term SBO(Station Black-Out) situation that is required to over 72 hours cooling. Therefore PAFS is needed to change of design for 72 hours cooling. In order to acquirement of long terms cooling using PAFS, heat exchanger tube has to be submerged in water tank for long time. However, water in the tank is evaporated by transferred heat from heat exchanger tubes, so water level is gradually lowered as time goes on. The heat removal capacity of air cooling heat exchanger is core parameter that is used for decision of applicability on passive air-water combined cooling system using PAFS in long term cooling. In this study, the development of MARS input model and plant accident analysis are performed for the prediction of the heat removal capacity of air cooling heat exchanger. From analysis result, it is known that inflow air velocity is the decisive factor of the heat removal capacity and predicted air velocity is lower than required air velocity. But present heat transfer model and predicted air velocity have uncertainty. So, if changed design of PAFS that has over 4.6 kW heat removal capacity in each tube, this type heat exchanger can be applied to long term cooling of the nuclear power plant.

  18. Dynamic properties of cationic diacyl-glycerol-arginine-based surfactant/phospholipid mixtures at the air/water interface.

    Science.gov (United States)

    Lozano, Neus; Pinazo, Aurora; Pérez, Lourdes; Pons, Ramon

    2010-02-16

    In this Article, we study the binary surface interactions of 1,2-dimyristoyl-rac-glycero-3-O-(N(alpha)-acetyl-L-arginine) hydrochloride (1414RAc) with 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) on 0.1 M sodium chloride solutions. 1414RAc is a novel monocationic surfactant that has potential applications as an antimicrobial agent, is biodegradable, and shows a toxicity activity smaller than that of other commercial cationic surfactants. DPPC phospholipid was used as a model membrane component. The dynamic surface tension of 1414RAc/DPPC aqueous dispersions injected into the saline subphase was followed by tensiometry. The layer formation for the mixtures is always accelerated with respect to DPPC, and surprisingly, the surface tension reduction is faster and reaches lower surface tension values at surfactant concentration below its critical micellar concentration (cmc). Interfacial dilational rheology properties of mixed films spread on the air/water interface were determined by the dynamic oscillation method using a Langmuir trough. The effect of surfactant mole fraction on the rheological parameters of 1414RAc/DPPC mixed monolayers was studied at a relative amplitude of area deformation of 5% and a frequency of 50 mHz. The monolayer viscoelasticity shows a nonideal mixing behavior with predominance of the surfactant properties. This nonideal behavior has been attributed to the prevalence of electrostatic interactions.

  19. Molecular dynamics simulations of peptides at the air-water interface: influencing factors on peptide-templated mineralization.

    Science.gov (United States)

    Jain, Alok; Jochum, Mara; Peter, Christine

    2014-12-30

    Biomineralization is the intricate, biomedically highly relevant process by which living organisms deposit minerals on biological matrices to stiffen tissues and build skeletal structures and shells. Rapaport and coworkers ( J. Am. Chem. Soc. 2000 , 122 , 12523 ; Adv. Funct. Mater. 2008 , 18 , 2889 ; Acta Biomater. 2012 , 8 , 2466 ) have designed a class of self-assembling amphiphilic peptides that are capable of forming hydrogels and attracting ions from the environment, generating structures akin to the extracellular matrix and promoting bone regeneration. The air-water interface serves both in experiment and in simulations as a model hydrophobic surface to mimic the cell's organic-aqueous interface and to investigate the organization of the peptide matrix into ordered β-pleated monolayers and the subsequent onset of biomineral formation. To obtain insight into the underlying molecular mechanism, we have used molecular dynamics simulations to study the effect of peptide sequence on aggregate stability and ion-peptide interactions. We find-in excellent agreement with experimental observations-that the nature of the peptide termini (proline vs phenylalanine) affect the aggregate order, while the nature of the acidic side chains (aspartic vs glutamic acid) affect the aggregate's stability in the presence of ions. These simulations provide valuable microscopic insight into the way ions and peptide templates mutually affect each other during the early stages of biomineralization preceding nucleation.

  20. Preparative separation of isovitexin and isoorientin from Patrinia villosa Juss by high-speed counter-current chromatography.

    Science.gov (United States)

    Peng, Jinyong; Fan, Guorong; Hong, Zhanying; Chai, Yifeng; Wu, Yutian

    2005-05-13

    High-speed counter-current chromatography (HSCCC) with a solvent system composed of ethyl acetate-n-butanol-water (2:1:3, v/v/v) was used to isolate and separate two C-glycosylflavones from Patrinia villosa Juss, a traditional Chinese medicine. The separation produced 42.9 mg isovitexin and 20.1 mg isoorientin with purities of 99.3% and 98.5%, respectively as determined by high-performance liquid chromatography (HPLC) in one step elution from 250 mg crude extract, and identification was performed by MS, 1H NMR and 13C NMR. It is the first report of discovering isovitexin and isoorientin from the plant of Patrinia genus.

  1. Two-stage fractionation of polar alkaloids from Rhizoma coptidis by countercurrent chromatography considering the strategy of reactive extraction.

    Science.gov (United States)

    Li, Yang; Cai, Fanfan; Zhang, Min; Zhang, Hongyang; Wang, Yuerong; Hu, Ping

    2015-01-23

    Separation of polar alkaloids by countercurrent chromatography (CCC) is challengeable due to their close partition behaviors in solvent system. In this paper, a two-stage method for isolation of epiberberine, jatrorrhizine, palmatine, coptisine, and berberine from Rhizoma coptidis was presented. The first stage separation performed on CCC was based on the principle of reactive extraction. Trifluoroacetic acid was acted as a modulator to selectively react with alkaloids, which changed their partition coefficients in solvent system. Purified epiberberine and other partially separated targets were eluted by ammonium adjusted mobile phase. In the second stage, four alkaloids were purified in pH-zone-refining CCC mode. All the targets collected were over 97% pure determined by HPLC. The method developed demonstrates performing of reactive extraction on standard CCC as an option for separation of polar alkaloids from medicinal plants.

  2. Isolation of chlorogenic acid from Mutellina purpurea L. herb using high-performance counter-current chromatography.

    Science.gov (United States)

    Sieniawska, Elwira; Skalicka-Woźniak, Krystyna

    2014-01-01

    The aim of the study was to explore proper isolation conditions of chlorogenic acid from the herb of Mutelina purpurea L. - a new source of this bioactive molecule. The accelerated solvent extraction (ASE) with 40% aqueous solution of methanol combined with high-performance counter-current chromatography (HPCCC) was utilised for the efficient extraction and the separation of chlorogenic acid from the M. purpurea herb in less than 30 min. The structure of the obtained compound was confirmed by mass spectrometry and NMR analysis. The preparative HPCCC was performed using the mixture of ethyl acetate, butanol and water (4:1:5, v/v/v) in the reverse-phase mode. The chlorogenic acid was isolated from this herb for the first time, yielding 96% purity. The ASE with 40% methanol combined with HPCCC separation was proven to be a useful tool for quick and efficient isolation of chlorogenic acid from M. purpurea.

  3. Separation and purification of astaxanthin from Phaffia rhodozyma by preparative high-speed counter-current chromatography.

    Science.gov (United States)

    Du, Xiping; Dong, Congcong; Wang, Kai; Jiang, Zedong; Chen, Yanhong; Yang, Yuanfan; Chen, Feng; Ni, Hui

    2016-09-01

    An effective high-speed counter-current chromatography (HSCCC) method was established for the preparative isolation and purification of astaxanthin from Phaffia rhodozyma. With a two-phase solvent system composed of n-hexane-acetone-ethanol-water (1:1:1:1, v/v/v/v), 100mg crude extract of P. rhodozyma was separated to yield 20.6mg of astaxanthin at 92.0% purity. By further one step silica gel column chromatography, the purity reached 99.0%. The chemical structure of astaxanthin was confirmed by thin layer chromatography (TLC), UV spectroscopy scanning, high performance liquid chromatography with a ZORBAX SB-C18 column and a Waters Nova-pak C18 column, and ESI/MS/MS.

  4. Preparative isolation of guaipyridine sesquiterpene alkaloid from Artemisia rupestris L. flowers using high-speed counter-current chromatography.

    Science.gov (United States)

    Su, Zhen; Wu, Hankui; Yang, Yi; Aisa, Haji Akber; Slukhan, Usmanova; Aripova, Salimakhon

    2008-07-01

    Although the medicinal plant Artemisia rupestris L. has been widely researched for several decades, its alkaloids have never been isolated before. To our surprise, the alkaloids in the plant were not detected in the stems but detected in the flowers. Herein, a novel and strange guaipyridine sesquiterpene alkaloid with a carboxyl group named rupestine was purified successfully from the total alkaloids extracted from the flowers by high-speed counter-current chromatography (HSCCC). The two-phase solvent system used was composed of ethyl acetate-methanol-water (8:1:7, v/v/v). Fifty six milligrams of rupestine was obtained at over 97% purity and 95% recovery from 200 mg of the total alkaloids in one-step separation. Its structure was elucidated by spectroscopic methods including high resolution ESI-MS, (1)H NMR, (13)C NMR, Heteronuclear Multiple Bond Correlation (HMBC), Heteronuclear Single Quantum Coherence (HSQC), and Nuclear Overhauser Enhancement Spectroscopy (NOESY).

  5. Preparative isolation and purification of xanthohumol from hops (Humulus lupulus L.) by high-speed counter-current chromatography.

    Science.gov (United States)

    Chen, Qi-He; Fu, Ming-Liang; Chen, Miao-Miao; Liu, Jing; Liu, Xiao-Jie; He, Guo-Qing; Pu, Shou-Cheng

    2012-05-01

    Xanthohumol (XN) and related prenylflavonoids are the main bioactive components of hops (Humulus lupulus L.). The current work is to investigate the use of high-speed counter-current chromatography (HSCCC) in search for high isolation of xanthohumol from hops. A solvent system consisted of n-hexane-ethyl acetate-methanol-water at a volume ratio of 5:5:4:3 was employed. The results demonstrated that the constructed method could be well applied for the isolation of xanthohumol from hops extract. After HSCCC isolation procedure, the purity of xanthohumol was over 95% assayed by HPLC and the yield of extraction was 93.60%. The chemical structure identification of xanthohumol was carried out by UV, (1)H NMR and (13)C NMR. The present results demonstrated that xanthohumol could be efficiently obtained using a single HSCCC step from H. lupulus L. extract.

  6. Isolation and purification of orientin and vitexin from Trollius chinensis Bunge by high-speed counter-current chromatography.

    Science.gov (United States)

    Yu, Xiao-Xue; Huang, Jie-Yun; Xu, Dan; Xie, Zhi-Yong; Xie, Zhi-Sheng; Xu, Xin-Jun

    2014-01-01

    Orientin and vitexin are the two main bioactive compounds in Trollius chinensis Bunge. In this study, a rapid method was established for the isolation and purification of orientin and vitexin from T. chinensis Bunge using high-speed counter-current chromatography in one step, with a solvent system of ethyl acetate-ethanol-water (4:1:5, v/v/v). A total of 9.8 mg orientin and 2.1 mg vitexin were obtained from 100 mg of the ethyl acetate extract, with purities of 99.2% and 96.0%, respectively. Their structures were identified by UV, MS and NMR. The method was efficient and convenient, which could be used for the preparative separation of orientin and vitexin from T. chinensis Bunge.

  7. Comparison of preparative reversed phase liquid chromatography and countercurrent chromatography for the kilogram scale purification of crude spinetoram insecticide.

    Science.gov (United States)

    DeAmicis, Carl; Edwards, Neil A; Giles, Michael B; Harris, Guy H; Hewitson, Peter; Janaway, Lee; Ignatova, Svetlana

    2011-09-09

    Reversed phase HPLC (RP-HPLC) and high performance countercurrent chromatography (HPCCC) were compared for the pilot scale purification of two semi-synthetic spinosyns, spinetoram-J and spinetoram-L, the major components of the commercial insecticide spinetoram. Two, independently performed, 1 kg, purification campaigns were compared. Each method resulted in the isolation of both components at a purity of >97% and yields for spinetoram-J and spinetoram-L of >93% and ≥ 63% of theoretical, respectively. The HPCCC process produced a 2-fold higher throughput and consumed approximately 70% less solvent than preparative scale RP-HPLC, the volume of product containing fractions from HPCCC amounted to 7% of that produced by HPLC and so required much less post-run processing.

  8. Isolation and Purification of Oridonin from the Whole Plant of Isodon rubescens by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    ChunYue Yu

    2011-09-01

    Full Text Available Semi-preparative high-speed counter-current chromatography (HSCCC was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v. The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance liquid chromatography (HPLC. A total of 40.6 mg of oridonin with the purity of 73.5% was obtained in less than 100 min from 100 mg of crude Isodon rubescens extract. The chemical structure of the compound was identified by IR, 1H-NMR and 13C-NMR.

  9. Effect of gas-liquid flow pattern and microbial diversity analysis of a pilot-scale biotrickling filter for anoxic biogas desulfurization.

    Science.gov (United States)

    Almenglo, Fernando; Bezerra, Tercia; Lafuente, Javier; Gabriel, David; Ramírez, Martín; Cantero, Domingo

    2016-08-01

    Hydrogen sulfide removal from biogas was studied under anoxic conditions in a pilot-scale biotrickling filter operated under counter- and co-current gas-liquid flow patterns. The best performance was found under counter-current conditions (maximum elimination capacity of 140 gS m(-3) h(-1)). Nevertheless, switching conditions between co- and counter-current flow lead to a favorable redistribution of biomass and elemental sulfur along the bed height. Moreover, elemental sulfur was oxidized to sulfate when the feeding biogas was disconnected and the supply of nitrate (electron acceptor) was maintained. Removal of elemental sulfur was important to prevent clogging in the packed bed and, thereby, to increase the lifespan of the packed bed between maintenance episodes. The larger elemental sulfur removal rate during shutdowns was 59.1 gS m(-3) h(-1). Tag-encoded FLX amplicon pyrosequencing was used to study the diversity of bacteria under co-current flow pattern with liquid recirculation and counter-current mode with a single-pass flow of the liquid phase. The main desulfurizing bacteria were Sedimenticola while significant role of heterotrophic, opportunistic species was envisaged. Remarkable differences between communities were found when a single-pass flow of industrial water was fed to the biotrickling filter.

  10. Aggregation behaviors of PEO-PPO-ph-PPO-PEO and PPO-PEO-ph-PEO-PPO at an air/water interface: experimental study and molecular dynamics simulation.

    Science.gov (United States)

    Gong, Houjian; Xu, Guiying; Liu, Teng; Xu, Long; Zhai, Xueru; Zhang, Jian; Lv, Xin

    2012-09-25

    The block polyethers PEO-PPO-ph-PPO-PEO (BPE) and PPO-PEO-ph-PEO-PPO (BEP) are synthesized by anionic polymerization using bisphenol A as initiator. Compared with Pluronic P123, the aggregation behaviors of BPE and BEP at an air/water interface are investigated by the surface tension and dilational viscoelasticity. The molecular construction can influence the efficiency and effectiveness of block polyethers in decreasing surface tension. BPE has the most efficient ability to decrease surface tension of water among the three block polyethers. The maximum surface excess concentration (Γ(max)) of BPE is larger than that of BEP or P123. Moreover, the dilational modulus of BPE is almost the same as that of P123, but much larger than that of BEP. The molecular dynamics simulation provides the conformational variations of block polyethers at the air/water interface.

  11. The interaction of eugenol with cell membrane models at the air-water interface is modulated by the lipid monolayer composition.

    Science.gov (United States)

    Gonçalves, Giulia E G; de Souza, Fernanda S; Lago, João Henrique G; Caseli, Luciano

    2015-12-01

    Eugenol, a natural phenylpropanoid derivative with possible action in biological surfaces as microbicide, anesthetic and antioxidant, was incorporated in lipid monolayers of selected lipids at the air-water interface, representing cell membrane models. Interaction of eugenol with the lipids dipalmitoylphosphatidylcholine (DPPC), dioctadecyldimethylammonium bromide (DODAB), and dipalmitoylphosphatidylserine (DPPS) could be inferred by means of surface pressure-area isotherms and Polarization-Modulation Reflection-Absorption Spectroscopy. The interaction showed different effects on the different lipids. A higher monolayer expansion was observed for DPPS and DODAB, while more significant effects on the polar groups of the lipids were observed for DPPS and DPPC. These results pointed to the fact that the interaction of eugenol with lipid monolayers at the air-water interface is modulated by the lipid composition, which may be important to comprehend at the molecular level the interaction of this drug with biological surfaces.

  12. Structure and orientation changes of omega- and gamma-gliadins at the air-water interface: a PM-IRRAS spectroscopy and Brewster angle microscopy study.

    Science.gov (United States)

    Banc, Amélie; Desbat, Bernard; Renard, Denis; Popineau, Yves; Mangavel, Cécile; Navailles, Laurence

    2007-12-18

    Microscopic and molecular structures of omega- and gamma-gliadin monolayers at the air-water interface were studied under compression by three complementary techniques: compression isotherms, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and Brewster angle microscopy (BAM). For high molecular areas, gliadin films are homogeneous, and a flat orientation of secondary structures relative to the interface is observed. With increasing compression, the nature and orientation of secondary structures changed to minimize the interfacial area. The gamma-gliadin film is the most stable at the air-water interface; its interfacial volume is constant with increasing compression, contrary to omega-gliadin films whose molecules are forced out of the interface. gamma-Gliadin stability at a high level of compression is interpreted by a stacking model.

  13. Non-Contact to Contact Transition: Direct Measurements of Interaction Forces between a Solid Probe and a Planar Air-Water Interface

    Institute of Scientific and Technical Information of China (English)

    WU Di; WANG Yi-Zhen; ZHANG Jin-Xiu

    2007-01-01

    The interaction force between a solid probe and a planar air-water interface is measured by using an atomic force microscope. It is demonstrated that during the approach of the probe to the air-water interface, the force curves decline all the time due to the van der Waals attraction and induces a stable profile of water surface raised. When the tip approaches very close to the water surface, force curves jump suddenly, reflecting the complex behaviour of the unstable water surface. With a theoretical analysis we conclude that before the tip touches water surface,two water profiles appear, one stable and the other unstable. Then, with further approaching, the tip touches water surface and the non-contact to contact transition occurs.

  14. The configuration of water on rough natural surfaces: Implications for understanding air-water interfacial area, film thickness, and imaging resolution

    Science.gov (United States)

    Kibbey, Tohren C. G.

    2013-08-01

    Previous studies of air-water interfacial areas in unsaturated porous media have often distinguished between interfacial area corresponding to water held by capillary forces between grains and area corresponding to water associated with solid surfaces. The focus of this work was on developing a better understanding of the nature of interfacial area associated with solid surfaces following drainage of porous media. Stereoscopic scanning electron microscopy was used to determine surface elevation maps for eight different surfaces of varying roughness. An algorithm was developed to calculate the true configuration of an air-water interface in contact with the solid surface as a function of capillary pressure. The algorithm was used to calculate surface-associated water configurations for capillary pressures ranging from 10 to 100 cm water. The results of the work show that, following drainage, the configuration of surface-associated water is dominated by bridging of macroscopic surface roughness features over the range of capillary pressures studied, and nearly all of the surface-associated water is capillary held. As such, the thicknesses of surface-associated water were found to be orders-of-magnitude greater than might be expected at the same capillary pressures based on calculations of adsorbed film thickness. The fact that capillary forces in air-water interfaces dominate surface-associated water configuration means that interface shapes are largely unaffected by microscopic surface roughness, and interfaces are considerably smoother than the underlying solid. As such, calculations suggest that microscopic surface roughness likely has minimal impact on the accuracy of surface-associated air-water interfacial areas determined by limited-resolution imaging methods such as computed microtomography.

  15. Absolute Orientation of Molecules with Competing Hydrophilic Head Groups at the Air/Water Interface Probed with Sum Frequency Generation Vibrational Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Feng Wang; Zhi Huang; Zhifeng Cui; Hongfei Wang

    2009-01-01

    The constructive or destructive spectral interference between the molecular groups oriented up and down at the interface in the sum-frequency generation (SFG) spectra provides a direct measurement of the absolute orientation of these molecular groups. This simple approach can be employed to interrogate absolute molecular orientations other than using the complex absolute phase measurement in the SFG studies. We used the -CN group in the p-cyanophenol (PCP) molecule as the internal phase standard, and we measured the phases of the SFG fields of the -CN groups in the 3,5-dimethyl-4-hydroxy-benzonitrile (35DMHBN)and 2,6-dimethyl-4-hydroxy-benzonitrile (26DMHBN) at the air/water interface by measuring the SFG spectra of the aqueous surfaces of the mixtures of the PCP, 35DMHBN, and 26DMHBN solutions. The results showed that the 35DMHBN had its -CN group pointing into the aqueous phase; while the 26DMHBN, similar to the PCP, had its -CN group pointing away from the aqueous phase. The tilt angles of the -CN group for both the 35DMHBN and 26DMHBN molecules at the air/water interface were around 25°-45° from the interface normal. These results provided insights on the understanding of the detailed balance of the competing factors, such as solvation of the polar head groups, hydrogen bonding and hydrophobic effects, etc., on influencing the absolute molecular orientation at the air/water interface.

  16. Vibrational sum-frequency generation spectroscopy of ionic liquid 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate at the air-water interface

    Science.gov (United States)

    Saha, Ankur; SenGupta, Sumana; Kumar, Awadhesh; Choudhury, Sipra; Naik, Prakash D.

    2016-08-01

    The structure and orientation of room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate [PF3(C2F5)3], commonly known as [bmim][fap], have been investigated at the air-[bmim][fap] and air-water interfaces, employing vibrational sum-frequency generation (VSFG) spectroscopy. The VSFG spectra in the CH stretch region suggest presence of the [bmim] cation at the interfaces. Studies reveal that the butyl chain protrudes out into air, and the imidazolium ring lies almost planar to the interface. The CH stretch intensities get enhanced at the air-water interface, mainly because of polar orientation of imidazolium cation induced by interfacial water molecules. The OH stretch intensities are also enhanced at the air-water interface due to polar orientation of interfacial water molecules induced by [bmim][fap]. The Brewster angle microscopy suggests self aggregation of [bmim][fap] in the presence of water, and the aggregation becomes extensive showing dense surface domains with time. However, the surface pressure is almost unaffected due to aggregation.

  17. The 8th International Conference on Counter-current Chromatography held at Brunel University, London, UK, July 23-25, 2014.

    Science.gov (United States)

    Ignatova, Svetlana; Sutherland, Ian

    2015-12-18

    The 8th International Conference on Counter-current Chromatography (CCC2014) was held at Brunel University London from July 23rd to 25th, 2014. It has been 14 years since Brunel hosted the first International Conference on CCC (CCC2000) at the beginning of the millennium and therefore, it was a good opportunity to review the progress of this emerging technology and particularly the impact it is having with industry today.

  18. Preparative isolation and analysis of alcohol dehydrogenase inhibitors from Glycyrrhiza uralensis root using ultrafiltration combined with high-performance liquid chromatography and high-speed countercurrent chromatography.

    Science.gov (United States)

    Chen, Miao; Liu, Liangliang; Chen, Xiaoqing

    2014-07-01

    A simple, rapid, and effective assay based on ultrafiltration combined with high-performance liquid chromatography and high-speed countercurrent chromatography was developed for screening and purifying alcohol dehydrogenase inhibitors from Glycyrrhiza uralensis root extract. Experiments were carried out to optimize binding conditions including alcohol dehydrogenase concentration, incubation time, temperature, and pH. By comparing the chromatograms, three compounds were found possessing alcohol dehydrogenase binding activity in Glycyrrhiza uralensis root. Under the target-guidance of ultrafiltration combined with the high-performance liquid chromatography experiment, liquiritin (1), isoliquiritin (2), and liquiritigenin (3) were separated by high-speed countercurrent chromatography using ethyl acetate/methanol/water (5:1:4) as the solvent system. The alcohol dehydrogenase inhibitory activities of these three isolated compounds were assessed; compound 2 showed strongest inhibitory activity with an IC50 of 8.95 μM. The results of the present study indicated that the combinative method using ultrafiltration, high-performance liquid chromatography and high-speed countercurrent chromatography could be widely applied for the rapid screening and isolation of enzyme inhibitors from complex mixtures.

  19. Semisynthetic preparation and isolation of dimeric procyanidins B1-B8 from roasted hazelnut skins (Corylus avellana L.) on a large scale using countercurrent chromatography.

    Science.gov (United States)

    Esatbeyoglu, Tuba; Juadjur, Andreas; Wray, Victor; Winterhalter, Peter

    2014-07-23

    Dimeric procyanidins B1-B8 were produced via semisynthesis from a polymeric proanthocyanidin fraction of hazelnut skins (Corylus avellana L.). This polymeric fraction was found to consist mostly of (+)-catechin and (-)-epicatechin as upper units. Therefore, according to the choice of nucleophile agent, it is possible to semisynthesize dimeric procyanidins B1, B3, B6, and B7 with (+)-catechin and B2, B4, B5, and B8 with (-)-epicatechin. The semisynthetic mixtures were separated on a preparative scale using high-speed countercurrent chromatography (HSCCC) and low-speed rotary countercurrent chromatography (LSRCCC). C4 → C8 linked dimeric procyanidins B1-B4 were isolated in amounts of 350-740 mg. To the best of the authors' knowledge this is the first study isolating dimeric procyanidins B1-B8 in large amounts with countercurrent chromatography. Moreover, the dimeric prodelphinidins B1, B2, and B3 and their structural elucidation by (1)H NMR spectroscopy without derivatization are described for hazelnuts as natural compounds for the first time.

  20. Preparative isolation of a cytotoxic principle of a forest mushroom Suillus luteus by sodium dodecyl sulfate based "salting-in" countercurrent chromatography.

    Science.gov (United States)

    Yang, Zhi; Hu, Xueqian; Wu, Shihua

    2016-02-01

    In the course of screening new anticancer natural products, an edible forest mushroom Suillus luteus (L. Ex Franch). Gray was found to have potent cytotoxicity against several human cancer cells. However, the lipophilic sample made some countercurrent chromatography solvent systems emulsify, which caused difficulties in the separation of its cytotoxic components. Here, we found that the addition of an organic salt sodium dodecyl sulfate could efficiently shorten the settling time of the mushroom sample solutions by eliminating the emulsification of two-phase solvent systems. Moreover, we found that sodium dodecyl sulfate could play a new "salting-in" role and made the partition coefficients of the solutes decrease with the increased concentrations. Thus, a sodium dodecyl sulfate based salting-in countercurrent chromatography method has been successfully established for the first time for preparative isolation of a cytotoxic principle of the mushroom. The active component was identified as isosuillin. Whole results indicated that sodium dodecyl sulfate could be used as an efficient salting-in reagent for two-phase solvent system selection and targeted countercurrent chromatography isolation. It is very useful for current natural products isolation and drug discovery.

  1. Enantioseparation of (DL)-tryptophan by spiral tube assembly counter-current chromatography and evaluation of mass transfer rate for enantiomers.

    Science.gov (United States)

    Tong, Shengqiang; Ito, Yoichiro; Ma, Ying

    2014-12-29

    Spiral tube assembly counter-current chromatography was successfully applied in enantioseparation of dl-tryptophan using bovine serum albumin as chiral selector. An improved biphasic aqueous-aqueous solvent system 12.0% (w/w) polyethyleneglycol 8000-9.0% (w/w) dibasic potassium phosphate-0.1% ammonia-78.9% water was used as the solvent system for counter-current chromatography, in which bovine serum albumin was predominantly distributed in the lower phase of the two-phase aqueous system. The aqueous-aqueous solvent system gave a very high enantioselectivity for d- and l-tryptophan at α=2.605 along with distribution ratio DD=1.200 and DL=0.461. High peak resolution was obtained for enantioseparation of 2.0mg of dl-tryptophan by spiral tube assembly counter-current chromatography under room temperature. It was found that 0.1% ammonia added in the aqueous-aqueous solvent system greatly improved the enantioseparations. An unusual extremely broad peak for l-tryptophan was observed during enantioseparations. In order to give an explanation, mass transfer rates of d- and l-enantiomers through the interface between the two phases were measured. It was found that l-tryptophan showed lower mass transfer rate than d-tryptophan. Further discussions were proposed for possible reasons for mass transfer rate difference between the enantiomers.

  2. Evaluation of gardenia yellow using crocetin from alkaline hydrolysis based on ultra high performance liquid chromatography and high-speed countercurrent chromatography.

    Science.gov (United States)

    Inoue, Koichi; Tanada, Chihiro; Nishikawa, Hiroaki; Matsuda, Satoru; Tada, Atsuko; Ito, Yusai; Min, Jun Zhe; Todoroki, Kenichiro; Sugimoto, Naoki; Toyo'oka, Toshimasa; Akiyama, Hiroshi

    2014-12-01

    Gardenia yellow is globally the most valuable spice and food color. It is generally a mixture of water-soluble carotenoid glycosyl esters which consist of crocetin bis(gentiobiosyl) ester as the main component. Crocetin is a natural carotenoid dicarboxylic acid that may be a candidate drug for pharmaceutical development, however, it is either present in trace amounts or is absent in natural gardenia yellow products. We here propose that crocetin produced by alkaline hydrolysis can be used to qualitatively evaluate gardenia yellow products using an ultra high performance liquid chromatographic assay. A useful and efficient isolation technique for isolating high-purity crocetin from gardenia yellow using high-speed countercurrent chromatography is described. High-speed countercurrent chromatographic fractionation followed by an ultra high performance liquid chromatographic assay showed that trans-crocetin is easily converted to about 15% cis-crocetin (85% trans-crocetin). Crocetin in gardenia yellow was quantitatively evaluated. Our approach is based on the hydrolysis process for converting crocetin glycosyl esters to crocetin before evaluation and isolation using the ultra high performance liquid chromatographic and high-speed countercurrent chromatographic methods. The combination of hydrolysis and chromatographic methods allows evaluation of the purity and quantity of crocetin in gardenia yellow.

  3. Dynamics of a two-phase flow through a minichannel: Transition from churn to slug flow

    Science.gov (United States)

    Górski, Grzegorz; Litak, Grzegorz; Mosdorf, Romuald; Rysak, Andrzej

    2016-04-01

    The churn-to-slug flow bifurcations of two-phase (air-water) flow patterns in a 2mm diameter minichannel were investigated. With increasing a water flow rate, we observed the transition of slugs to bubbles of different sizes. The process was recorded by a digital camera. The sequences of light transmission time series were recorded by a laser-phototransistor sensor, and then analyzed using the recurrence plots and recurrence quantification analysis (RQA). Due to volume dependence of bubbles velocities, we observed the formation of periodic modulations in the laser signal.

  4. Theory and Experiment on the Measurement of Kinetic Rate Constants for Surfactant Exchange at an Air/Water Interface.

    Science.gov (United States)

    Pan; Green; Maldarelli

    1998-09-15

    The paper focuses on the measurement of the rate constants for the kinetic steps of adsorption and desorption of surfactant between an air/water surface and the aqueous bulk sublayer adjacent to the surface. Kinetic constants are determined in nonequilibrium experiments in which either a clean surface is contacted with a bulk solution and surfactant diffuses toward and adsorbs onto the interface, or the area of an established monolayer in equilibrium with an underlying solution is changed, and surfactant exchanges between the surface and bulk. The dynamic tension change due to the surfactant exchange is measured, and compared to predictions of kinetic-diffusive transport models in order to infer the kinetic coefficients as well the diffusion coefficients. Model comparisons for highly surface active surfactants have resolved only the diffusion coefficient as the transport was found to be diffusion controlled; kinetic constants have only been established for less active materials such as alcohols or bolaform surfactants. In this study, we demonstrate that kinetics can be differentiated from diffusion in clean interface adsorption and re-equilibration if high bulk concentrations of the surfactant are used, or in re-equilibration, if the surface is compressed sufficiently. We first establish theoretically that mass transfer shifts from diffusion-limited to mixed as the bulk concentration increases in clean interface adsorption, or the surface compression is increased in re-equilibration. We then experimentally verify this idea by using the polyethoxylated surfactant C12E6 (C12H25 (OCH2CH2)6-OH) and by measuring dynamic surface tensions in clean interface adsorption and re-equilibration, respectively by the shape analysis of pendant bubbles. We find values of 6 x 10(-10) m2/s for the diffusion coefficient, and 1.4 x 10(-5) m/sec and 1.4 x 10(-4) s-1 for the adsorption and desorption rate constants, respectively, in a Frumkin kinetic formulation. While the adsorption

  5. Surface properties and conformation of Nephila clavipes spider recombinant silk proteins at the air-water interface.

    Science.gov (United States)

    Renault, Anne; Rioux-Dubé, Jean-François; Lefèvre, Thierry; Pezennec, Stéphane; Beaufils, Sylvie; Vié, Véronique; Tremblay, Mélanie; Pézolet, Michel

    2009-07-21

    The dragline fiber of spiders is composed of two proteins, the major ampullate spidroins I and II (MaSpI and MaSpII). To better understand the assembly mechanism and the properties of these proteins, the adsorption behavior of the recombinant proteins of the spider Nephila clavipes produced by Nexia Biotechnologies Inc. has been studied at the air-water interface using ellipsometry, surface pressure, rheological, and infrared measurements. The results show that the adsorption is more rapid and more molecules are present at the interface for MaSpII than for MaSpI. MaSpII has thus a higher affinity for the interface than MaSpI, which is consistent with its higher aggregation propensity in water. The films formed at the interface consist of networks containing a high content of intermolecular beta-sheets as revealed by the in situ polarization modulation infrared absorption reflection spectra. The infrared results further demonstrate that, for MaSpI, the beta-sheets are formed as soon as the proteins adsorb to the interface while for MaSpII the beta-sheet formation occurs more slowly. The amount of beta-sheets is lower for MaSpII than for MaSpI, most likely due to the presence of proline residues in its sequence. Both proteins form elastic films, but they are heterogeneous for MaSpI and homogeneous for MaSpII most probably as a result of a more ordered and slower aggregation process for MaSpII. This difference in their mechanism of assembly and interfacial behaviors does not seem to arise from their overall hydrophobicity or from a specific pattern of hydrophobicity, but rather from the longer polyalanine motifs, lower glycine content, and higher proline content of MaSpII. The propensity of both spidroins to form beta-sheets, especially the polyalanine blocks, suggests the participation of both proteins in the silk's beta-sheet crystallites.

  6. Intraday evaporation and heat fluxes variation at air-water interface of extremely shallow lakes in Chilean Andean Plateau

    Science.gov (United States)

    Vergara, Jaime; de la Fuente, Alberto

    2016-04-01

    Salars are landscapes formed by evapo-concentration of salts that usually have extremely shallow terminal lagoons (de la Fuente & Niño, 2010). They are located in the altiplanic region of the Andes Mountains of Chile, Argentina, Bolivia and Peru, and they sustain highly vulnerable and isolated ecosystems in the Andean Desert. These ecosystems are sustained by benthic primary production, which is directly linked to mass, heat and momentum transfer between the water column and the atmosphere (de la Fuente, 2014). Despite the importance of these transport processes across the air-water interface, there are few studies describing their intraday variation and how they are influenced by the stability of the atmospheric boundary layer in the altiplano. The main objective of this work is to analyze the intraday vertical transport variation of water vapor, temperature and momentum between the atmosphere and a shallow water body on Salar del Huasco located in northern Chile (20°19'40"S, 68°51'25"W). To achieve this goal, we measured atmospheric and water variables in a campaign realized on late October 2015, using high frequency meteorological instruments (a sonic anemometer with an incorporated infrared gas analyzer, and a standard meteorological station) and water sensors. From these data, we characterize the intraday variation of water vapor, temperature and momentum fluxes, we quantify the influence of the atmospheric boundary layer stability on them, and we estimate transfer coefficients associated to latent heat, sensible heat, hydrodynamic drag and vertical transport of water vapor. As first results, we found that latent and sensible heat fluxes are highly influenced by wind speed rather buoyancy, and we can identify four intraday intervals with different thermo-hydrodynamic features: (1) cooling under stable condition with wind speed near 0 from midnight until sunrise; (2) free convection with nearly no wind speed under unstable condition from sunrise until midday

  7. Numerical simulation of two-phase turbulent flow in hydraulic and hydropower engineering

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In connection with the specific features of high velocity aerated flow generated by hydraulic engineering structures,the mathematical model is developed for high turbulence air-water two-phase flow with the use of twin flow theoretical model in this paper.Furthermore the numerical method is proposed to treat bubbled flows.In addition,on the basis of air-water stratified twin flow model,the new calculation methods and free surface tracking technique are proposed to describe complicated movements of the free surface.Finally,the proposed model is used to calculate artificial aerated flows.The computed results coincide quite well with experimental results.This means that the proposed method can provide solid basis for practical engineering design.

  8. Synthesis of chemically-modified single-walled carbon nanotubes by counter-current ammonia gas injection into the induction thermal plasma process

    Science.gov (United States)

    Shahverdi, Ali

    Pristine single-walled carbon nanotubes (SWCNTs) are poorly dispersible and insoluble in many solvents and need to be chemically modified prior to their use in many applications. This work is focused on the investigation of the synthesis of chemically modified SWCNTs material through an in situ approach. The main objectives of the presented research are: 1) to explore the in situ chemical process during the synthesis of SWCNT and 2) to closely examine the effect of a reactive environment on SWCNTs. Effects of the catalyst type and content on the SWCNTs final product, synthesized by induction thermal plasma (ITP), were studied to replace toxic cobalt (Co) in the feedstock. In this regard, three different catalyst mixtures (i.e. Ni-Y2O3, Ni-Co-Y2O3, and Ni-Mo-Y2O3) were used. Experimental results showed that the catalyst type affects the quality of the SWCNT final product. Similar quality SWCNTs can be produced when the same amount of Co was replaced by Ni. Moreover, the results observed in this experimental work were further explained by thermodynamic calculation results. Thermogravimetry (TG) was used throughout the work to characterize the SWCNTs product. TG was firstly standardized by studying the effects of three main instrumental parameters (temperature ramp, TR, initial mass of the sample, IM, and gas flow rate, FR) on the Tonset and full-width half maximum (FWHM) obtained from TG and derivative TG graphs of carbon black, respectively. Therefore, a two-level factorial statistical design was performed. The statistical analysis showed that the effect of TR, IM, and to a lower extent, FR, is significant on FWHM and insignificant on Tonset. A methodology was then developed based upon the SWCNTs synthesis using the ITP system, through an in situ chemistry approach. Ammonia (NH3) was selected and counter-currently injected into the ITP reactor at three different flow rates and by four different nozzle designs. Numerical simulation indicated a better mixing of NH3 in

  9. Two Phase Flow Mapping and Transition Under Microgravity Conditions

    Science.gov (United States)

    Parang, Masood; Chao, David F.

    1998-01-01

    In this paper, recent microgravity two-phase flow data for air-water, air-water-glycerin, and air- water-Zonyl FSP mixtures are analyzed for transition from bubbly to slug and from slug to annular flow. It is found that Weber number-based maps are inadequate to predict flow-pattern transition, especially over a wide range of liquid flow rates. It is further shown that slug to annular flow transition is dependent on liquid phase Reynolds number at high liquid flow rate. This effect may be attributed to growing importance of liquid phase inertia in the dynamics of the phase flow and distribution. As a result a new form of scaling is introduced to present data using liquid Weber number based on vapor and liquid superficial velocities and Reynolds number based on liquid superficial velocity. This new combination of the dimensionless parameters seem to be more appropriate for the presentation of the microgravity data and provides a better flow pattern prediction and should be considered for evaluation with data obtained in the future. Similarly, the analysis of bubble to slug flow transition indicates a strong dependence on both liquid inertia and turbulence fluctuations which seem to play a significant role on this transition at high values of liquid velocity. A revised mapping of data using a new group of dimensionless parameters show a better and more consistent description of flow transition over a wide range of liquid flow rates. Further evaluation of the proposed flow transition mapping will have to be made after a wider range of microgravity data become available.

  10. Interfacial shear stress in stratified flow in a horizontal rectangular duct

    Energy Technology Data Exchange (ETDEWEB)

    Lorencez, C.; Kawaji, M. [Univ. of Toronto (Canada); Murao, Y. [Tokushima Univ. (Japan)] [and others

    1995-09-01

    Interfacial shear stress has been experimentally examined for both cocurrent and countercurrent stratified wavy flows in a horizontal interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress from the measurements were examined and the results have been compared with existing correlations. Some differences were found in the estimated interfacial shear stress values at high gas flow rates which could be attributed to the assumptions and procedures involved in each method. The interfacial waves and secondary motions were also found to have significant effects on the accuracy of Reynolds stress and turbulence kinetic energy extrapolation methods.

  11. Forces on bends and T-joints due to multiphase flow

    NARCIS (Netherlands)

    Belfroid, S.P.C.; Cargnelutti, M.F.; Schiferli, W.; Osch, M.M.E. van

    2010-01-01

    To be able to assess the mechanical integrity of piping structures for loading to multiphase flow conditions, air-water experiments were carried out in a horizontal 1" pipe system. Forces and accelerations were measured on a number of bends and T-joint configurations for a wide range of operating co

  12. LOREF: Air cooler optimisation with reduction of ice and frost formation - Optimisation of lamella air-coolers/evaporators of air/water heat pumps - Part 1: theoretical and experimental research; LOREF: Luftkuehler-Optimierung mit Reduktion von Eis- und Frostbildung - Optimierung des Lamellenluftkuehlers/Verdampfers von Luft/Wasser-Waermepumpen - Teil 1: theoretische und experimentelle Untersuchungen

    Energy Technology Data Exchange (ETDEWEB)

    Berlinger, L.; Imholz, M.; Albert, M.; Wellig, B.; Hilfiker, K.

    2008-04-15

    The use of air/water heat pumps for heating of houses is progressively increasing. It is to be expected that the average coefficient of performance (COP) can be improved substantially over the next decade. Its success will depend on controlling and reducing the formation of frost and ice which reduce the air flow and the heat and mass transfer in the fin tube evaporator. In the LOREF research project a mathematical-physical simulation program has been developed which permits to calculate the formation of condensate, ice and frost and also the pressure loss of the air as a function of space and time at any condition of the ambient air. The theoretical results have been validated by numerous experiments in which the air temperature and humidity, the temperature difference and the air velocity have been systematically varied. Particular emphasis has been given to the geometries of the fin tube evaporator. Several fin partitions along the cooler have been investigated. Using the simulation program the evaporator of a commercial heat pump was optimized and experimentally compared to the original evaporator. The resulting seasonal performance factors were nearly equal what confirms the small differences obtained by simulations. Nevertheless, the optimized evaporator features advantages in respect of the defrosting with ambient air because of its bigger fin spacing and the resulting decrease in pressure drop. The results of the LOREF research project are now the basis for the overall optimization of air/water heat pumps. (author)

  13. NUMERICAL SIMULATION OF SKIMMING FLOW OVER MILD STEPPED CHANNEL

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; LEE Joseph Hun-wei

    2006-01-01

    Numerical simulation of stepped channel flow was conducted using turbulence models based on the VOF technique. Stepped channel flow is a complicated air-water two-phase flow with free surface, which can be divided into three flow regimes: skimming flow, nappe flow and transition flow. The characteristics of skimming flow over mild stepped channel was investigated, including friction factors, air concentration profiles velocity field, clear-water and bulked depths, static pressure, etc. Smooth channel flow was also simulated to compare the hydraulic characteristics of the stepped channel flow with the smooth one. Comparisons between the computed and the measured were made. Furthermore, comparison of the computed air concentration with Straub and Anderson's data was also performed. The Fluent 6.1 software was employed to conduct this numerical simulation work.

  14. Design of a coil satellite centrifuge and its performance on counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives with polar organic-aqueous two-phase solvent systems.

    Science.gov (United States)

    Shinomiya, Kazufusa; Tokura, Koji; Kimura, Emiru; Takai, Midori; Harikai, Naoki; Yoshida, Kazunori; Yanagidaira, Kazuhiro; Ito, Yoichiro

    2015-05-01

    A new high-speed counter-current chromatograph, named coil satellite centrifuge (CSC), was designed and fabricated in our laboratory. The CSC apparatus produces the satellite motion such that the coiled column simultaneously rotates around the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3). In order to achieve this triplicate rotary motion without twisting of the flow tube, the rotation of each axis was determined by the following formula: ω1=ω2+ω3. This relation enabled to lay out the flow tube without twisting by the simultaneous rotation of three axes. The flow tube was introduced from the bottom side of the apparatus into the sun axis of the first rotary frame reaching the upper side of the planet axis and connected to the column in the satellite axis. The performance of the apparatus was examined on separation of 4-methylumbelliferyl (MU) sugar derivatives as test samples with organic-aqueous two-phase solvent systems composed of ethyl acetate/1-butanol/water (3:2:5, v/v) for lower phase mobile and (1:4:5, v/v) for upper phase mobile. With lower phase mobile, five 4-MU sugar derivatives including β-D-cellobioside (Cel), β-D-glucopyranoside, α-D-mannopyranoside, β-D-fucopyranoside and α-L-fucopyranoside (α-L-Fuc) were separated with the combined rotation around each axis at counterclockwise (CCW) (ω1) - CCW (ω2) - CCW (ω3) by the flow tube distribution. With upper phase mobile, three 4-MU sugar derivatives including α-L-Fuc, β-D-galactopyranoside and Cel were separated with the combined rotation around each axis at clockwise (CW) (ω1) - CW (ω2) - CW (ω3) by the flow tube distribution. A series of experiments on peak resolution and stationary phase retention revealed that better partition efficiencies were obtained at the flow rate of 0.5 mL/min (column 1) and 0.8 mL/min (column 2) for lower phase mobile and 0.2 mL/min (column 1) and 0.4 mL/min (column 2) for upper phase

  15. Preparative purification of five bioactive components from Agrimonia pilosa Ledeb by high-speed counter-current chromatography.

    Science.gov (United States)

    Wang, Yan; Liu, Mozhen; Zheng, Lingli; Yin, Lianhong; Xu, Lina; Qi, Yan; Ma, Xiaochi; Liu, Kexin; Peng, Jinyong

    2012-08-01

    High-speed counter-current chromatography (HSCCC) coupled with ultraviolet (UV) detection or evaporative light-scattering detection was successfully applied for preparative separation of five bioactive compounds from Agrimonia pilosa Ledeb. In preliminary process, D101 macroporous resin was used to separate the crude extract of the plant and four fractions (20, 40, 50, and 60% aqueous ethanol elutions) were produced. Then, these fractions were directly subjected to HSCCC purification. Five chemicals including taxifolin-3-glucoside (6.4 mg), quercetin-3-rhamnoside (13.0 mg), tiliroside (14.7 mg), agrimonolide (21.4 mg), and tormentic acid (29.8 mg) with the purities of 94.24, 95.37, 97.42, 95.29, and 96.34% were separated from each 200 mg prepared fraction. The purities were analyzed by high-performance liquid chromatography, and the chemical structures of the products were identified by UV detection, mass spectrometry, nuclear magnetic resonance, and the standards. This paper used a simple method to separate five bioactive compounds from A. pilosa Ledeb, and it could provide a new idea for the purification of bioactive compounds from other medicinal plants.

  16. Microwave-Assisted Extraction and Purification of Arctiin and Arctigenin from Fructus Arctii by High-Speed Countercurrent Chromatography.

    Science.gov (United States)

    Lü, Haitao; Sun, Zhaoyun; Shan, Hu; Song, Jiying

    2016-03-01

    An efficient method for the rapid extraction, separation and purification of bioactive lignans, arctiin and arctigenin, from Fructus arctii by microwave-assisted extraction coupled with high-speed countercurrent chromatography was developed. The optimal extraction conditions of arctiin and arctigenin were evaluated by orthogonal array. Arctigenin could be converted from arctiin by hydrochloric acid hydrolysis. The separations were performed at a preparative scale with two-phase solvents composed of ethyl acetate-ethanol-water (5 : 1 : 5, v/v/v) for arctiin, and n-hexane-ethyl acetate-ethanol-water (4 : 4 : 3 : 4, v/v/v/v) for arctigenin. From 500 mg of crude extract sample, 122.3 mg of arctiin and 45.7 mg of arctigenin were obtained with the purity of 98.46 and 96.57%, and the recovery of 94.3 and 81.6%, respectively. Their structures were determined by comparison with the high-performance liquid chromatography retention time of standard substance as well as UV, FT-IR, electrospray ion source (ESI)-MS, (1)H-NMR and (13)C-NMR spectrum. According to the antioxidant activity assay, arctigenin had stronger 1,1-diphenyl-2-picrylhydrazyl free radicals scavenging activity.

  17. [Preparative isolation and purification of cinnamoyl-C-glycoside chromone from aloe vera by high-speed countercurrent chromatography].

    Science.gov (United States)

    Pan, Xia; Cao, Xueli; Dong, Yinmao; Zhao, Hua

    2005-01-01

    Aloe chromone is a group of anti-inflammatory and anti-tyrosinase constituents found in aloe vera leaves. High-speed countercurrent chromatography (HSCCC) is reported for the preparative isolation and purification of a chromone from aloe vera. The crude extract was obtained by a series of pretreatment of aloe vera leaves and extracted from decolorizing active carbon with methanol. Then the extract was distributed between dichloromethane and water, and the organic part was then subjected to HSCCC for the isolation of chromone constituents. The chromone compounds with a high performance liquid chromatographic grade (>95%) was isolated through two step HSCCC separations by employing two solvent systems composed of chloroform-methanol-water and dichloromethane-methanol-water at volume ratios of 4/3/2 and 5/4/2, respectively. The chromone was finally identified as cinnamoyl-C-glycoside chromone by ultraviolet (UV), fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H NMR and 13C NMR).

  18. Purification of two triterpenoids from Schisandra chinensis by macroporous resin combined with high-speed counter-current chromatography.

    Science.gov (United States)

    Zhu, Lijie; Li, Bin; Liu, Xiuying; Meng, Xianjun

    2014-10-01

    A method for preparative purification of corosolic acid and nigranoic acid from Schisandra chinensis (SC) was established using a combination of macroporous absorption resin column separation and high-speed counter-current chromatography (HSCCC). The crude extracts obtained from SC using 70% ethanol were separated on a macroporous resin column and then eluted with a graded ethanol series. The 70% ethanol fraction was used as the sample for separation of the two triterpenoids by HSCCC. The two-phase solvent system used for HSCCC separation was chloroform-n-butanol-methanol-water (10:0.5:7:4, v/v/v/v). The upper phase was used as the stationary phase of HSCCC. Corosolic acid (16.4 mg) of 96.3% purity and nigranoic acid (9.5 mg) of 98.9% purity were obtained in a one-step HSCCC separation from 100 mg of the sample. The structures of corosolic acid and nigranoic acid were identified by (1)H-nuclear magnetic resonance (NMR) and (13)C-NMR.

  19. Isolation of secondary metabolites from Hortia oreadica (Rutaceae) leaves through high-speed counter-current chromatography.

    Science.gov (United States)

    Severino, Vanessa Gisele Pasqualotto; Cazal, Cristiane de Melo; Forim, Moacir Rossi; da Silva, Maria Fátima das Graças Fernandes; Rodrigues-Filho, Edson; Fernandes, João Batista; Vieira, Paulo Cezar

    2009-05-08

    High-speed counter-current chromatography (HSCCC) with a two-phase solvent system (hexane-ethanol-acetonitrile-water 10:8:1:1, v/v) was applied to examine the leaves of Hortia oreadica, which afforded the known limonoid guyanin (1), the alkaloids rutaecarpin (2) and dictamnine (6), the dihydrocinnamic acid derivatives methyl 5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoate (3), 5,8-dimethoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoic acid (4), together with the new E-3,4-dimethoxy-alpha(3-hydroxy-4-carbomethoxyphenyl)cinnamic acid (5). The recovery of compounds 1-6 was determined by comparison with LC-atmospheric pressure chemical ionization MS/MS data: 66.2%, 93.1%, 102.5%, 101.2%, 99.0% and 84.9%, respectively. Compound 3 showed IC(50) of 23.6microM against Plasmodium falciparum and 15.6microM against Trypanosoma brucei rhodesienses and was not toxic to KB cells (IC(50)>100microM).

  20. Separation and purification of glucosinolates from crude plant homogenates by high-speed counter-current chromatography.

    Science.gov (United States)

    Fahey, Jed W; Wade, Kristina L; Stephenson, Katherine K; Chou, F Edward

    2003-05-01

    Glucosinolates are anionic, hydrophilic plant secondary metabolites which are of particular interest due to their role in the prevention of cancer and other chronic and degenerative diseases. The separation and purification of glucosinolates from a variety of plant sources (e.g. seeds of broccoli, arugula and the horseradish tree), was achieved using high-speed counter-current chromatography (HSCCC). A high-salt, highly polar system containing 1-propanol-acetonitrile-saturated aqueous ammonium sulfate-water (1:0.5:1.2:1), was run on a semi-preparative scale and then transferred directly to preparative scale. Up to 7 g of a concentrated methanolic syrup containing about 10% glucosinolates was loaded on an 850-ml HSCCC column, and good separation and recovery were demonstrated for 4-methylsulfinylbutyl, 3-methylsulfinylpropyl, 4-methylthiobutyl, 2-propenyl and 4-(rhamnopyranosyloxy)benzyl glucosinolates. Multiple injections (5 to 6 times) were performed with well-preserved liquid stationary phase under centrifugal force. Pooled sequential runs with broccoli seed extract yielded about 20 g of its predominant glucosinolate, glucoraphanin, which was produced at > 95% purity and reduced to powdered form.

  1. Response of Mode Water and Subtropical Countercurrent to Greenhouse Gas and Aerosol Forcing in the North Pacific

    Institute of Scientific and Technical Information of China (English)

    WANG Liyi; LIU Qinyu; XU Lixiao; XIE Shang-Ping

    2013-01-01

    The response of the North Pacific Subtropical Mode Water and Subtropical Countercurrent (STCC) to changes in greenhouse gas (GHG) and aerosol is investigated based on the 20th-century historical and single-forcing simulations with the Geophysical Fluid Dynamics Laboratory Climate Model version 3 (GFDL CM3).The aerosol effect causes sea surface temperature (SST)to decrease in the mid-latitude North Pacific,especially in the Kuroshio Extension region,during the past five decades (1950-2005),and this cooling effect exceeds the warming effect by the GHG increase.The STCC response to the GHG and aerosol forcing are opposite.In the GHG (aerosol) forcing run,the STCC decelerates (accelerates) due to the decreased (increased) mode waters in the North Pacific,resulting from a weaker (stronger) front in the mixed layer depth and decreased (increased) subduction in the mode water formation region.The aerosol effect on the SST,mode waters and STCC more than offsets the GHG effect.The response of SST in a zonal band around 40°N and the STCC to the combined forcing in the historical simulation is similar to the response to the aerosol forcing.

  2. ORGANIC-HIGH IONIC STRENGTH AQUEOUS SOLVENT SYSTEMS FOR SPIRAL COUNTER-CURRENT CHROMATOGRAPHY: GRAPHIC OPTIMIZATION OF PARTITION COEFFICIENT.

    Science.gov (United States)

    Zeng, Yun; Liu, Gang; Ma, Ying; Chen, Xiaoyuan; Ito, Yoichiro

    2013-01-10

    A new series of organic-high ionic strength aqueous two-phase solvents systems was designed for separation of highly polar compounds by spiral high-speed counter-current chromatography. A total of 21 solvent systems composed of 1-butanol-ethanol-saturated ammonium sulfate-water at various volume ratios are arranged according to an increasing order of polarity. Selection of the two-phase solvent system for a single compound or a multiple sample mixture can be achieved by two steps of partition coefficient measurements using a graphic method. The capability of the method is demonstrated by optimization of partition coefficient for seven highly polar samples including tartrazine (K=0.77), tryptophan (K=1.00), methyl green (K= 0.93), tyrosine (0.81), metanephrine (K=0.89), tyramine (K=0.98), and normetanephrine (K=0.96). Three sulfonic acid components in D&C Green No. 8 were successfully separated by HSCCC using the graphic selection of the two-phase solvent system.

  3. Accelerated separation of GC-amenable lipid classes in plant oils by countercurrent chromatography in the co-current mode.

    Science.gov (United States)

    Hammann, Simon; Englert, Michael; Müller, Marco; Vetter, Walter

    2015-12-01

    Triacylglycerols represent the major part (>90%) in most plant oils and have to be eliminated, when the minor compounds such as phytosterols or tocopherols should be analyzed. Here, we used an all liquid-liquid chromatographic technique, countercurrent chromatography (CCC), to fractionate the minor lipids before gas chromatography (GC) analysis. To cover the wide range of polarity of the minor compounds, we used the co-current mode, in which both mobile and stationary phase are pumped through the system. This allowed to elute substances which partitioned almost exclusively in the stationary phase within 90 min. After testing with standard compounds, the method was applied to the separation of sesame oil and sunflower oil samples. The abundant triacylglycerols could be effectively separated from tocopherols, phytosterols, diacylglycerols, and free fatty acids in the samples, and these compounds could be analyzed (after trimethylsilylation) by GC coupled with mass spectrometry. After the enrichment caused by the CCC fractionation, we were also able to identify the tocopherol derivative α-tocomonoenol, which had not been described in sunflower oil before. Also, separation of sesame oil yielded a mixture of the polar compounds sesamin and sesamolin without further impurities.

  4. Modeling of the simulated countercurrent moving-bed chromatographic reactor used for the oxidative coupling of methane

    Energy Technology Data Exchange (ETDEWEB)

    Tonkovich, A.L.Y. [Pacific Northwest Lab., Richland, WA (United States); Carr, R.W. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Sciences

    1994-09-01

    The oxidative coupling reaction of methane (OCM) is a potential industrial reaction for the efficient production of ethylene. Replacement of current technologies requires significant product yield improvements. An experimental novel reactor design, the modified simulated countercurrent moving-bed chromatographic reactor (SCMCR), has reported improved ethane and ethylene product yields over other reported values. An understanding of the reactor operation is aided by concurrent mathematical modeling. The model mimics the exact experimental reactor configuration. Four sections are used; each section contains a reaction column and two separation columns connected in series. The feed is switched from section to section at discrete intervals. Reaction occurs in the first column and is followed by product and reactant separation in the ensuing section columns. Langmuir adsorption isotherms are used. The model does not incorporate the realistic and complex kinetics rising, from the OCM, rather a simplified reaction term is used to qualitatively gain insight into the operation of the modified SCMCR. A unimolecular reaction network is used in the model. The rate constants are set to permit a small fractional conversion, 5% per pass, at the concentrations during the first cycle. Similarly to the experimental reactor, the model adds a make-up feed (defined as percentage of the original feed, where excess methane is fed during the first cycle of the experimental reactor) to augment lost reactants.

  5. Separation of phenolic acids and flavonoids from Trollius chinensis Bunge by high speed counter-current chromatography.

    Science.gov (United States)

    Qin, Yanhua; Liang, Yizeng; Ren, Dabing; Qiu, Ximin; Li, Xi

    2015-09-15

    In this work, eleven compounds were successfully separated from Trollius chinensis Bunge by using a two-step high-speed counter-current chromatography (HSCCC) method. NRTL-SAC (nonrandom two-liquid segment activity coefficient) method, a newly developed solvent system selection strategy, was applied to screening the suitable biphasic liquid systems. Hexane/ethyl acetate/ethanol/water (3:7:3:7, v/v) solvent system was used in the first step, while the hexane/ethyl acetate/methanol/water (1:2:1:2, 1:4:1:4, 1:9:1:9, v/v) systems were employed in the second step. The chemical structures of the separated compounds were identified by UV, high resolution ESI-MS and MS/MS data. The separated compounds are 3,4-dihydroxyphenylethanol (1), vanillic acid (2), orientin (3), vitexin (4), veratric acid (5), 2″-O-(3‴, 4‴-dimethoxybenzoyl) orientin (6), 2″-O-feruloylorientin (7), 2″-O-feruloylvitexin (8), 2″-O-(2‴-methylbutyryl) vitexin (9), 2″-O-(2‴-methylbutyryl) isoswertiajaponin (10), 2″-O-(2‴-methylbutyryl) isoswertisin (11). The results demonstrate that HSCCC is a powerful tool for the separation of compounds from extremely complex samples.

  6. Comprehensive multi-channel multi-dimensional counter-current chromatography for separation of tanshinones from Salvia miltiorrhiza Bunge.

    Science.gov (United States)

    Meng, Jie; Yang, Zhi; Liang, Junling; Zhou, Hui; Wu, Shihua

    2014-01-03

    Multi-dimensional chromatography offers the increased resolution and peak capacity by coupling of multiple columns with the same or different separation mechanisms. In this work, a novel multi-channel multi-dimensional counter-current chromatography (CCC) has been successfully constructed and used for several two-dimensional (2D) and three-dimensional (3D) CCC separations including 2D A×B/A×C, A×B-C and A-B×C, and 3D A×B×C systems. These 2D and 3D CCC systems were further applied to separate the bioactive tanshinones from the extract of Tanshen (or Danshen, Salvia miltiorrhiza Bunge), a famous Traditional Chinese Medicine (TCM). As a result, the developed 2D and 3D CCC methods were successful and efficient for resolving the tanshinones from complex extracts. Compared to the 1D multiple columns CCC separation, the 2D and 3D CCC decrease analysis time, reduce solvent consumption and increase sample throughput significantly. It may be widely used for current drug development, metabolomic analysis and natural product isolation.

  7. Extraction and preparative purification of tanshinones from Salvia miltiorrhiza Bunge by high-speed counter-current chromatography.

    Science.gov (United States)

    Sun, Ailing; Zhang, Yongqing; Li, Aifeng; Meng, Zhaoling; Liu, Renmin

    2011-07-01

    A method for extraction and preparative separation of tanshinones from Salvia miltiorrhiza Bunge was successfully established in this paper. Tanshinones from Salvia miltiorrhiza Bunge were extracted using ethyl acetate as the extractant under reflux. The extracts were then purified by high speed counter-current chromatography (HSCCC) with light petroleum-ethyl acetate-methanol-water (6:4:6.5:3.5, v/v) as the two phase solvent system. The upper phase was used as the stationary phase and the lower phase as the mobile phase. 8.2mg of dihydrotanshinone I, 5.8 mg of 1,2,15,16-tetrahydrotanshiquinone, 26.3mg of cryptotanshinone, 16.2mg of tanshinone I, 25.6 mg of neo-przewaquinone A, 68.8 mg of tanshinone IIA and 9.3mg of miltirone were obtained from 400mg of extracts from Salvia miltiorrhiza Bunge in one-step HSCCC separation, with the purity of 97. 6%, 95.1%, 99.0%, 99.1%, 93.2%, 99.3% and 98.7%, respectively, as determined by HPLC area normalization method. Their chemical structures were identified by ¹H NMR.

  8. Schinus terebinthifolius countercurrent chromatography (Part II): Intra-apparatus scale-up and inter-apparatus method transfer.

    Science.gov (United States)

    Costa, Fernanda das Neves; Vieira, Mariana Neves; Garrard, Ian; Hewitson, Peter; Jerz, Gerold; Leitão, Gilda Guimarães; Ignatova, Svetlana

    2016-09-30

    Countercurrent chromatography (CCC) is being widely used across the world for purification of various materials, especially in natural product research. The predictability of CCC scale-up has been successfully demonstrated using specially designed instruments of the same manufacturer. The reality is that the most of CCC users do not have access to such instruments and do not have enough experience to transfer methods from one CCC column to another. This unique study of three international teams is based on innovative approach to simplify the scale-up between different CCC machines using fractionation of Schinus terebinthifolius berries dichloromethane extract as a case study. The optimized separation methodology, recently developed by the authors (Part I), was repeatedly performed on CCC columns of different design available at most research laboratories across the world. Hexane - ethyl acetate - methanol - water (6:1:6:1, v/v/v/v) was used as solvent system with masticadienonic and 3β-masticadienolic acids as target compounds to monitor stationary phase retention and calculate peak resolution. It has been demonstrated that volumetric, linear and length scale-up transfer factors based on column characteristics can be directly applied to different i.d., volume and length columns independently on instrument make in an intra-apparatus scale-up and inter-apparatus method transfer.

  9. Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Xikai; Wang, Mei; Liu, Daicheng [College of Life Science, Shandong Normal University, Jinan, Shandong (China); Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi, E-mail: wxjn1998@126.com [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China)

    2013-09-01

    An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-{beta}-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-{beta}-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

  10. Recovery of Butanol by Counter-Current Carbon Dioxide Fractionation with its Potential Application to Butanol Fermentation

    Directory of Open Access Journals (Sweden)

    Miriam Solana

    2016-06-01

    Full Text Available A counter-current CO2 fractionation method was applied as a mean to recover n-butanol and other compounds that are typically obtained from biobutanol fermentation broth from aqueous solutions. The influence of operating variables, such as solvent-to-feed ratio, temperature, pressure and feed solution composition was experimentally studied in terms of separation efficiency, butanol removal rate, total removal and butanol concentration in the extract at the end of the continuous cycle. With respect to the temperature and pressure conditions investigated, results show that the highest separation efficiency was obtained at 35 °C and 10.34 MPa. At these operating conditions, 92.3% of the butanol present in the feed solution was extracted, and a concentration of 787.5 g·L−1 of butanol in the extract was obtained, starting from a feed solution of 20 g·L−1. Selectivity was calculated from experimental data, concluding that our column performs much better than a single equilibrium stage. When adding ethanol and acetone to the feed solution, ethanol was detected in the water-rich fraction (raffinate, whereas the highest concentration of acetone was found in the butanol rich fraction (extract.

  11. Preparative Separation of Alkaloids from Picrasma quassioides (D. Don Benn. by Conventional and pH-Zone-Refining Countercurrent Chromatography

    Directory of Open Access Journals (Sweden)

    Qinghai Zhang

    2014-06-01

    Full Text Available Two high-speed countercurrent chromatography (HSCCC modes were compared by separation of major alkaloids from crude extract of Picrasma quassioides. The conventional HSCCC separation was performed with a two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (5:5:4.5:5.5, v/v/v/v with 200 mg loading. pH-Zone-refining CCC was performed with two-phase solvent system composed of petroleum ether–ethyl acetate–n-butanol–water (3:2:7:9, v/v/v/v where triethylamine (10 mM was added to the upper organic stationary phase and hydrochloric acid (5 mM was added to the lower aqueous phase with 2 g loading. From 2 g of crude extract, 87 mg of 5-methoxycanthin-6-one (a, 38 mg of 1-methoxy-β-carboline (b, 134 mg of 1-ethyl-4,8-dimethoxy-β-carboline (c, 74 mg of 1-ethoxycarbonyl-β-carboline (d, 56 mg of 1-vinyl-4,8-dimethoxy-β-carboline (e and 26 mg of 1-vinyl-4-dimethoxy-β-carboline (f were obtained with purities of over 97.0%. The results indicated that pH-zone-refining CCC is an excellent separations tool at the multigram level.

  12. Savinase action on bovine serum albumin (BSA) monolayers demonstrated with measurements at the air-water interface and liquid Atomic Force Microscopy (AFM) imaging

    DEFF Research Database (Denmark)

    Balashev, Konstantin; Callisen, Thomas H; Svendsen, Allan;

    2011-01-01

    We studied the enzymatic action of Savinase on bovine serum albumin (BSA) organized in a monolayer spread at the air/water interface or adsorbed at the mica surface. We carried out two types of experiments. In the first one we followed the degradation of the protein monolayer by measuring...... the surface pressure and surface area decrease versus time. In the second approach we applied AFM imaging of the supported BSA monolayers adsorbed on mica solid supports and extracted information for the enzyme action by analyzing the obtained images of the surface topography in the course of enzyme action...

  13. Experimental analysis on regeneration efficiency of countercurrent solar collector/regenerator%逆流太阳能溶液集热/再生器再生效率实验分析

    Institute of Scientific and Technical Information of China (English)

    彭冬根; 张小松

    2015-01-01

    对1m×2m×0.35m逆流太阳能溶液集热/再生器进行实验研究,分析了影响太阳能溶液集热/再生器再生效率的各种影响因素.实验研究发现,常温溶液再生存在明显两段式分布,溶液再生效率随空气流量的增加先增后减,存在最大值;溶液再生效率随溶液流量增加而递减.加热溶液综合再生效率升高;而加热再生用空气其综合再生效率下降.采用含湿量为20 g/kg再生用湿空气的再生效率比用含湿量为10 g/kg的再生用湿空气的再生效率小0.16.随着太阳辐射强度的提高,溶液再生效率也相应增加.因此,逆流太阳能溶液集热/再生器应在空气较干燥、太阳辐射强度较高时运行,并选取适合的空气流量.%A countercurrent solar solution collector/regenerator ( C/R) with experiment platform the size of 1 m( wide) ×2 m( long) ×0.35 m( high) was used for analyzing the factors influencing re-generation efficiency of solar C/R.It is found that there is an obvious two-stage distribution for re-generating solution at normal temperature.The regeneration efficiency of solution increases first and then decreases with the increase of air mass flow rates and there exists a maximum value.The regen-eration efficiency always decreases with the increase of solution flow rates.Heating solution leads to an increase of integrated regeneration efficiency;however, heating regeneration air decreases the in-tegrated regeneration efficiency.The regeneration efficiency is decreased by 0.16 by using humid air of 20 g/kg instead of using humid air of 10 g/kg.The regeneration efficiency increases correspond-ingly with the increase of the solar radiation intensity.The countercurrent solar solution C/R can op-erate better in dry air and high solar radiation conditions and a suitable air flow-rate should be select-ed to achieve better performance.

  14. Water behavior in a u-shaped flow channel of PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Quan, P.; Zhou, B.; Sobiesiak, A. [Windsor Univ., ON (Canada). Dept. of Mechanical, Automotive and Materials Engineering; Liu, Z.S. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2005-07-01

    A study was conducted to find a practical approach for predicting liquid water distribution in the U-shaped flow channels of a proton exchange membrane (PEM) fuel cell. Computational fluid dynamics modeling with the FLUENT software package was used to demonstrate the two-phase flow of the air-water transport process inside the channel. It was noted that no chemical reaction occurs inside the flow channels and the liquid water is formed either on the surfaces of the flow channels or inside the flow channels. The problem can therefore be simplified as a fluid mechanics problem with water sources inside its physical domain or on its boundaries. The volume-of-fluid (VOF) model was used to track dynamic air-water interactions. Three cases with a range of initial water phase distributions corresponding to different fuel cell operating conditions were simulated numerically to gain a better understanding of water behaviour inside the serpentine channel. It was concluded that the bend area in the serpentine flow field affects the fuel cell performance. This is because it influences the flow field which in turn influences the air-water flow and water liquid distribution inside the channel or along the inside channel surfaces. 15 refs., 1 tab., 11 figs.

  15. Study of a three-phase flow metering process for oil-water-gas flows; Etude d`un procede de mesure des debits d`un ecoulement triphasique de type eau-huile-gaz

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, Ch.

    1996-11-01

    We propose a theoretical and experimental study of a three-phase flow metering process for oil-water-gas flows. The selected process is based on a combination of a mixer, a Venturi and ultrasonic methods. To perform an experimental validation of this process an instrumented set-up for three-phase air-oil-water flows has been designed, conceived and adjusted. An original theoretical model have been built to predict three-phase dispersed flows across a contraction. Once validated with two-phase air-water, oil-water and air-oil-water flows data, this model has been used to solve the Venturi metering problems. After a critical review of the available techniques, the ultrasonic propagation velocity has been selected to determine two-phase liquid-liquid flow composition. Two original models have been developed to describe the ultrasonic propagation with the dispersed phase fraction. The comparison with experimental data in oil-water flows show the superiority of one of the two models, the scattering model. For the void fraction determination in air-water flows, the work of Bensler (1990) based on the ultrasonic attenuation measurement has been extended to take into account the multiple scattering effects. Finally these techniques have been combined to determine the different flow rates in air-water, oil-water flows. For two-phase air-water and oil-water flows the problem is solved and the flow rates are measured with a very good accuracy ({+-} 3%). The results quality obtained with three-phase oil-water-gas flows and the secure theoretical bases allowing their interpretation give us the opportunity to strongly recommend the development of an industrial prototype based on the process we studied. (author) 183 refs.

  16. Mechanism of Action of Thymol on Cell Membranes Investigated through Lipid Langmuir Monolayers at the Air-Water Interface and Molecular Simulation.

    Science.gov (United States)

    Ferreira, João Victor N; Capello, Tabata M; Siqueira, Leonardo J A; Lago, João Henrique G; Caseli, Luciano

    2016-04-05

    A major challenge in the design of biocidal drugs is to identify compounds with potential action on microorganisms and to understand at the molecular level their mechanism of action. In this study, thymol, a monoterpenoid found in the oil of leaves of Lippia sidoides with possible action in biological surfaces, was incorporated in lipid monolayers at the air-water interface that represented cell membrane models. The interaction of thymol with dipalmitoylphosphatidylcholine (DPPC) at the air-water interface was investigated by means of surface pressure-area isotherms, Brewster angle microscopy (BAM), polarization-modulation reflection-absorption spectroscopy (PM-IRRAS), and molecular dynamics simulation. Thymol expands DPPC monolayers, decreases their surface elasticity, and changes the morphology of the lipid monolayer, which evidence the incorporation of this compound in the lipid Langmuir film. Such incorporation could be corroborated by PM-IRRAS since some specific bands for DPPC were changed upon thymol incorporation. Furthermore, potential of mean force obtained by molecular dynamics simulations indicates that the most stable position of the drug along the lipid film is near the hydrophobic regions of DPPC. These results may be useful to understand the interaction between thymol and cell membranes during biochemical phenomena, which may be associated with its pharmaceutical properties at the molecular level.

  17. DLVO, hydrophobic, capillary and hydrodynamic forces acting on bacteria at solid-air-water interfaces: Their relative impact on bacteria deposition mechanisms in unsaturated porous media.

    Science.gov (United States)

    Bai, Hongjuan; Cochet, Nelly; Pauss, André; Lamy, Edvina

    2017-02-01

    Experimental and modeling studies were performed to investigate bacteria deposition behavior in unsaturated porous media. The coupled effect of different forces, acting on bacteria at solid-air-water interfaces and their relative importance on bacteria deposition mechanisms was explored by calculating Derjaguin-Landau-Verwey-Overbeek (DLVO) and non-DLVO interactions such as hydrophobic, capillary and hydrodynamic forces. Negatively charged non-motile bacteria and quartz sands were used in packed column experiments. The breakthrough curves and retention profiles of bacteria were simulated using the modified Mobile-IMmobile (MIM) model, to identify physico-chemical attachment or physical straining mechanisms involved in bacteria retention. These results indicated that both mechanisms might occur in both sand. However, the attachment was found to be a reversible process, because attachment coefficients were similar to those of detachment. DLVO calculations supported these results: the primary minimum did not exist, suggesting no permanent retention of bacteria to solid-water and air-water interfaces. Calculated hydrodynamic and resisting torques predicted that bacteria detachment in the secondary minimum might occur. The capillary potential energy was greater than DLVO, hydrophobic and hydrodynamic potential energies, suggesting that film straining by capillary forces might largely govern bacteria deposition under unsaturated conditions.

  18. Toward a unified picture of the water self-ions at the air-water interface: a density functional theory perspective.

    Science.gov (United States)

    Baer, Marcel D; Kuo, I-Feng W; Tobias, Douglas J; Mundy, Christopher J

    2014-07-17

    The propensities of the water self-ions, H3O(+) and OH(-), for the air-water interface have implications for interfacial acid-base chemistry. Despite numerous experimental and computational studies, no consensus has been reached on the question of whether or not H3O(+) and/or OH(-) prefer to be at the water surface or in the bulk. Here we report a molecular dynamics simulation study of the bulk vs interfacial behavior of H3O(+) and OH(-) that employs forces derived from density functional theory with a generalized gradient approximation exchange-correlation functional (specifically, BLYP) and empirical dispersion corrections. We computed the potential of mean force (PMF) for H3O(+) as a function of the position of the ion in the vicinity of an air-water interface. The PMF suggests that H3O(+) has equal propensity for the interface and the bulk. We compare the PMF for H3O(+) to our previously computed PMF for OH(-) adsorption, which contains a shallow minimum at the interface, and we explore how differences in solvation of each ion at the interface vs in the bulk are connected with interfacial propensity. We find that the solvation shell of H3O(+) is only slightly dependent on its position in the water slab, while OH(-) partially desolvates as it approaches the interface, and we examine how this difference in solvation behavior is manifested in the electronic structure and chemistry of the two ions.

  19. Experimentally probing the libration of interfacial water: the rotational potential of water is stiffer at the air/water interface than in bulk liquid.

    Science.gov (United States)

    Tong, Yujin; Kampfrath, Tobias; Campen, R Kramer

    2016-07-21

    Most properties of liquid water are determined by its hydrogen-bond network. Because forming an aqueous interface requires termination of this network, one might expect the molecular level properties of interfacial water to markedly differ from water in bulk. Intriguingly, much prior experimental and theoretical work has found that, from the perspective of their time-averaged structure and picosecond structural dynamics, hydrogen-bonded OH groups at an air/water interface behave the same as hydrogen-bonded OH groups in bulk liquid water. Here we report the first experimental observation of interfacial water's libration (i.e. frustrated rotation) using the laser-based technique vibrational sum frequency spectroscopy. We find this mode has a frequency of 834 cm(-1), ≈165 cm(-1) higher than in bulk liquid water at the same temperature and similar to bulk ice. Because libration frequency is proportional to the stiffness of water's rotational potential, this increase suggests that one effect of terminating bulk water's hydrogen bonding network at the air/water interface is retarding rotation of water around intact hydrogen bonds. Because in bulk liquid water the libration plays a key role in stabilizing reaction intermediates and dissipating excess vibrational energy, we expect the ability to probe this mode in interfacial water to open new perspectives on the kinetics of heterogeneous reactions at aqueous interfaces.

  20. Thin film formation at the air-water interface and on solid substrates of soluble axial substituted cis-bis-decanoate tin phthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Teran, Jose, E-mail: jcampos@correo.cua.uam.mx [Departamento de Procesos y Tecnologia, DCNI, Universidad Autonoma Metropolitana-Cuajimalpa, Artificios 40-sexto piso, Col. Hidalgo, D. F., 001120 (Mexico); Garza, Cristina [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, P. O. Box 20-364, D. F., 01000 (Mexico); Beltran, Hiram I. [Departamento de Ciencias Naturales, DCNI, Universidad Autonoma Metropolitana-Cuajimalpa, Artificios 40-sexto piso, Col. Hidalgo, D. F., 001120 (Mexico); Castillo, Rolando [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, P. O. Box 20-364, D. F., 01000 (Mexico)

    2012-01-01

    Herein we study thin films of a recent kind of soluble axial substituted cis-bis-decanoate-tin{sup IV} phthalocyanine (PcSn10) at the air/water interface, which were compressed isothermally and observed with Brewster Angle Microscopy. The air/water interfacial behavior of the films suggests that there are strong interactions among the PcSn10 molecules, which produces multilayers and 3D self-assemblies that prevent the formation of a Langmuir monolayer. Langmuir-Blodgett deposits of these films on both mica (negatively charged) and mild steel (positively charged) surfaces were developed. Information about the morphology of the film was obtained by using atomic force microscopy. We found structural differences in the PcSn10 thin films deposited on both substrates, suggesting that a combination of {pi}-{pi}, {sigma}-{pi} and Van der Waals interactions are the leading factors for the deposition, and consequently, for the control of supramolecular order. Our findings provide insights in the design of phthalocyanine molecules for the development of highly ordered and reproducible thin films.

  1. Comparison of pulsating DC and DC power air-water plasma jet: A method to decrease plume temperature and increase ROS

    Science.gov (United States)

    Liu, K.; Hu, H.; Lei, J.; Hu, Y.; Zheng, Z.

    2016-12-01

    Most air-water plasma jets are rich in hydroxyl radicals (•OH), but the plasma has higher temperatures, compared to that of pure gas, especially when using air as working gas. In this paper, pulsating direct current (PDC) power was used to excite the air-water plasma jet to reduce plume temperature. In addition to the temperature, other differences between PDC and DC plasma jets are not yet clear. Thus, comparative studies of those plasmas are performed to evaluate characteristics, such as breakdown voltage, temperature, and reactive oxygen species. The results show that the plume temperature of PDC plasma is roughly 5-10 °C lower than that of DC plasma in the same conditions. The •OH content of PDC is lower than that of DC plasma, whereas the O content of PDC plasma is higher. The addition of water leads in an increase in the plume temperature and in the production of •OH with two types of power supplies. The production of O inversely shows a declining tendency with higher water ratio. The most important finding is that the PDC plasma with 100% water ratio achieves lower temperature and more abundant production of •OH and O, compared with DC plasma with 0% water ratio.

  2. Application of Countercurrent Chromatography on Chiral Separation%逆流色谱技术在手性分离方面的应用

    Institute of Scientific and Technical Information of China (English)

    吕迎春; 樊竹青

    2014-01-01

    Countercurrent chromatography is a liquid -liquid partition chromatography,without the use of support body or carrier.It is of advantage for chiral separation.In this paper its recent application in chiral separation is reviewed.%逆流色谱是一种不用固态支撑体或载体的液液分配色谱技术,其分离原理具有手性制备性分离的优势。以近年采用逆流色谱技术对手性化合物分离的应用进行了综述。

  3. Preparative Separation of Two glycosides from Swertia Mussotti by High-Speed Counter-Current Chromatography%高速逆流色谱分离制备川西獐牙菜中两种苷类化合物

    Institute of Scientific and Technical Information of China (English)

    陈涛; 贾静; 王萍; 尤进茂; 刘永军; 李玉林

    2012-01-01

    A high performance method for isolation and purification of two glycosides from Swertia mussotti was successfully established by utilizing high-speed counter-current chromatography ( HSCCC). Separation was performed with a two-phase solvent system composed of n-butanol-chloroform-methanol-water (3.4:8:5 :6,v/v). 1-O-primevenosyl-3,7, 8-trimethoxyxanthone (11 mg) and isoorientin (24 mg) were isolated and purified in one-step elution from 100 mg crude sample under the conditions of a flow rate 1.5 mL/min in the initial 210 min followed by 2.5 mL/min,800 r/min and the detection wavelength of 254 run. HPLC analysis showed that the purity of two compounds was over 99%. Their chemical structures were confirmed by UV,1H- and 13C NMR.%采用高速逆流色谱从川西獐牙菜中分离制备了两种高纯度苷类化合物.以正丁醇-氯仿-甲醇-水(3.4∶8∶5∶6,v/v)为溶剂系统,主机转速为800 rpm,流速:O~210 min,1.5mL/min;210 ~360m in,2.5 mL/min,检测波长254 nm的条件下进行分离制备,在360 min内从100 mg样品中一步分离制备得到1-O-樱草糖-3,7,8-三甲氧基(口山)酮(Ⅰ,11 mg)和异荭草苷(Ⅱ,24 mg).经HPLC检测,两个化合物的纯度均在99%以上,结构由UV、1H和13C NMR鉴定.

  4. Separation and purification of the flavonoid from Cuminum cyminum L by high speed countercurrent chromatography%高速逆流色谱法分离制备孜然黄酮

    Institute of Scientific and Technical Information of China (English)

    吴素玲; 孙晓明; 张卫明; 杨艳; 张锋伦

    2012-01-01

    应用高速逆流色谱法分离制备了孜然中的黄酮类成分。以氯仿∶甲醇∶水=4∶4∶2(v∶v∶v)为两相溶剂系统,在主机转速为850r/min、流速1.8mL/min、检测波长254nm条件下进行分离制备。所得分离收集液经高效液相色谱法检测,结果表明,从孜然黄酮粗提物中分离得到了纯度超过90%的两种黄酮类成分;经干燥得样品重分别为26mg和24mg。%High-speed countercurrent chromatography (HSCCC) with a two-phase solvent system composed of chloroform-methanol-water (4:4:2) was applied to separate and purify two flavonoids from Cuminum cyminum L. The mobile phase was performed at a flow rate of 1.8mL/min,while the apparatus rotated at 850r/min and detected at 254nm. Two kinds of flavones were obtained and yielded 26mg and 24mg respectively. The results showed that the purities of two flavones were more than 90% determined by high performance liquid chromatography(HPLC) which was a simple and rapid method.

  5. Do periodic consolidations of Pacific countercurrents trigger global cooling by equatorially symmetric La Niña?

    Directory of Open Access Journals (Sweden)

    J. H. Duke

    2010-05-01

    Full Text Available A sporadic phenomenon of internal tide resonance (ITR in the western equatorial Pacific thermocline is shown to precede 11 of 12 major upturns in the Niño 3.4 index between 1992 and 2008. Observed ITR has up to 9 °C semidiurnal temperature excursions indicating thermocline heave, but is invisible in time resolution longer than one day. It is independent of westerly wind bursts (WWB. A hypothesis is advanced that (1 ITR dissipates vorticity, leading to Pacific countercurrent consolidation (PCC by reducing the vortex stretching term in Sverdrup balance. The consequence of lost vorticity survives ephemeral ITR events; (2 The specific surface area of countercurrents is reduced by PCC, which reduces frictional opposition to zonal gradient pressure, which triggers eastward advection at El Niño onset; (3 PCC also accelerates transfer of potential energy to the "pycnostad" below the Equatorial Undercurrent. This shoals the equatorial thermocline, leading to a distinct mode of equatorially symmetric La Niña (ESLN characterized by a winter monsoon cell above a "cold eye" that is separated from the South American continent, as in 1998; (4 Precessional southward intertropical convergence zone migration (ITCZ is an alternate PCC trigger, but its effect is modulated by obliquity; and (5 ESLN causes global cooling in all timescales by (a reduced Hadley cell water vapor production when its rising branch is above the cold eye, (b equatorward shift in southern circumpolar westerlies due to Hadley cell constriction, (c possible CO2 sequestration by increased EUC iron fertilized export production on the equator, and (d possible adjacent cloud seeding by biogenic dimethyl sulphide. Surprising coincidences of WWB with perigean eclipses suggest a parallel atmospheric tide influence. Proposed PCC-ESLN forcing operates in multiple timescales, beginning where the annual cycle of strong equinoctial tides coincides with the minimum perigee cycle. This

  6. Numerical and dimensional investigation of two-phase countercurrent imbibition in porous media

    KAUST Repository

    El-Amin, Mohamed

    2013-04-01

    In this paper, we introduce a numerical solution of the problem of two-phase immiscible flow in porous media. In the first part of this work, we present the general conservation laws for multiphase flows in porous media as outlined in the literature for the sake of completion where we emphasize the difficulties associated with these equations in their primitive form and the fact that they are, generally, unclosed. The second part concerns the 1D computation for dimensional and non-dimensional cases and a theoretical analysis of the problem under consideration. A time-scale based on the characteristic velocity is used to transform the macroscopic governing equations into a non-dimensional form. The resulting dimensionless governing equations involved some important dimensionless physical parameters such as Bond number Bo, capillary number Ca and Darcy number Da. Numerical experiments on the Bond number effect is performed for two cases, gravity opposing and assisting. The theoretical analysis illustrates that common formulations of the time-scale forces the coefficient Da12Ca to be equal to one, while formulation of dimensionless time based on a characteristic velocity allows the capillary and Darcy numbers to appear in the dimensionless governing equation which leads to a wide range of scales and physical properties of fluids and rocks. The results indicate that the buoyancy effects due to gravity force take place depending on the location of the open boundary. © 2012 Elsevier B.V. All rights reserved.

  7. Influence of a Southern Shift of the ITCZ from Quick Scatterometer Data on the Pacific North Equatorial Countercurrent

    Institute of Scientific and Technical Information of China (English)

    WU Fanghua; LIN Pengfei; LIU Hailong

    2012-01-01

    By analyzing the climatologically averaged wind stress during 2000-2007,it is found that the easterly wind stress in the northern tropical Pacific Ocean from Quick Scatterometer (QSCAT) data was stronger than those from Tropical Atmosphere Ocean (TAO) data and from National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis I.As a result,the Intertropical Convergence Zone (ITCZ) in the Pacific Ocean is more southward in the QSCAT data than in the NCEP/NCAR data.Relative to the NCEP wind,the southern shift of the ITCZ in the QSCAT data led to negative anomaly of wind stress curl north of a latitude of 6°N.The negative anomaly results in downward Ekman pumping in the central Pacific.The excessive local strong easterly wind also contributes to the downward Ekman pumping.This downward Ekman pumping suppresses the thermocline ridge,reduces the meridional thermocline slope and weakens the North Equatorial Countercurrent (NECC).These effects were confirmed by numerical experiments using two independent ocean general circulation models (OGCMs).Furthermore,the excessive equatorial easterly wind stress was also found to contribute to the weaker NECC in the OGCMs.A comparison between the simulations and observation data indicates that the stronger zonal wind stress and its southern shift of QSCAT data in the ITCZ region yield the maximum strength of the simulated NECC only 33% of the magnitude derived from observation data and even led to a "missing" NECC in the western Pacific.

  8. Preparative isolation and purification of two benzoxazinoid glucosides from Acanthus ilicifolius L. by high-speed counter-current chromatography.

    Science.gov (United States)

    Yin, Hao; Zhang, Si; Luo, Xiongming; Liu, Yonghong

    2008-09-26

    The first preparative separation of two benzoxazinoids, (2R)-2-O-beta-d-glucopyranosyl-2H-1,4-benzoxazin-3(4H)-one (HBOA-Glc) and (2R)-2-O-beta-d-glucopyranosyl-4-hydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA-Glc), by means of high-speed counter-current chromatography (HSCCC) from the n-butanol extract of Acanthus ilicifolius L. is presented. The two-phase solvent system containing ethyl acetate-n-butanol-0.5%NH(4)OH (2:3:5, v/v/v, system B) was selected for the one-step HSCCC separation of HBOA-Glc and DIBOA-Glc according to the partition coefficient values (K) for target compounds and the separation factor (alpha) between the two target compounds. In the one-step HSCCC separation using solvent B, from 100mg n-butanol extract of A. ilicifolius, 6.3 mg HBOA-Glc and 6.8 mg DIBOA-Glc were isolated with purities of 90.3% and 80.2%, respectively. In order to obtain the two target compounds with higher purity, a second separation process was developed comprising two steps. In the two-step separation, the sample was first pre-purified by HSCCC using ethyl acetate-n-butanol-water (2:3:5, v/v/v, system A) solvent system and then purified using solvent system B. A 100-mg amount of the n-butanol extracts of A. ilicifolius was separated to yield 5.8 mg of HBOA-Glc and 4.8 mg of DIBOA-Glc with purities of 97.1% and 94.8%, respectively, which were directly used for NMR analyses.

  9. Online control of the twin-column countercurrent solvent gradient process for biochromatography.

    Science.gov (United States)

    Krättli, M; Steinebach, F; Morbidelli, M

    2013-06-07

    A new control concept for the twin-column MCSGP process has been developed. The controller is based on two independent PID controllers each of which affects one side of the product collection window. Accordingly, the two controllers, although independent, can together shift the product collection along the elution chromatogram. The product stream collected during one entire process cycle is analyzed with an at-line HPLC allowing a direct feedback of the measured purity values to the controller. The two set points are given by the purity values with respect to weak and strong impurities in the product stream. The controller performance was tested with two systems: In the first one, a three component protein model mixture was considered. The controller stability and reliability was tested in conditions of both set point tracking and rejection of feed composition and pump flow rate disturbances. The complete experiment ran for 112h during which the desired purity values were always kept within the set points. A more realistic example was the purification of a monoclonal antibody supernatant from fragments and aggregates. In this case, the process reached specifications after five cycles, and kept them for 20h of operation in spite of ongoing disturbances in pump flow rates and feed composition. A new general start-up procedure was developed and tested in this particular purification process. The procedure starts from very simple initial conditions and let the controller to identify conditions, particularly for the recycle streams, which lead to yield and purity values significantly better than the corresponding values achieved in batch chromatography in specs.

  10. Preparative separation of bioactive compounds from essential oil of Flaveria bidentis (L.) Kuntze using steam distillation extraction and one step high-speed counter-current chromatography.

    Science.gov (United States)

    Wei, Yun; Du, Jilin; Lu, Yuanyuan

    2012-10-01

    In order to utilize and control the invasive weed, bioactive compounds from essential oil of Flaveria bidentis (L.) Kuntze were studied. Steam distillation extraction and one step high-speed counter-current chromatography were applied to separate and purify the caryophyllene oxide, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, and caryophyllene from essential oil of Flaveria bidentis (L.) Kuntze. The two-phase solvent system containing n-hexane/acetonitrile/ethanol (5:4:3, v/v/v) was selected for the one step separation mode according to the partition coefficient values (K) of the target compounds and the separation factor (α). The purity of each isolated fraction after a single high-speed counter-current chromatography run was determined by high performance liquid chromatography. A 3.2 mg of caryophyllene oxide at a purity of 92.6%, 10.4 mg of 7,11-dimethyl-3-methylene-1,6,10-dodecatriene at a purity of 99.1% and 5.7 mg of caryophyllene at a purity of 98.8% were obtained from 200 mg essential oil of Flaveria bidentis (L.) Kuntze. The chemical structures of these components were identified by GC-MS, (1) H-NMR, and (13) C-NMR.

  11. Three-phase solvent systems for the comprehensive separation of a wide variety of compounds from Dicranostigma leptopodum by high-speed counter-current chromatography.

    Science.gov (United States)

    Liu, Yanjuan; Chen, Xiaofen; Liu, JunXi; Di, Duolong

    2015-06-01

    A three-phase solvent system was efficiently applied for high-speed counter-current chromatography to separate secondary metabolites with a wide range of hydrophobicity in Dicranostigma leptopodum. The three-phase solvent system of n-hexane/methyl tert-butyl ether/acetonitrile/0.5% triethylamine (2:2:3:2, v/v/v/v) was selected for high-speed counter-current chromatography separation. The separation was initiated by filling the column with a mixture of intermediate phase and lower phase as a stationary phase followed by elution with upper phase to separate the hydrophobic compounds. Then the mobile phase was switched to the intermediate phase to elute the moderately hydrophobic compounds, and finally the polar compounds still retained in the column were fractionated by eluting the column with the lower phase. In this research, 12 peaks were eluted out in one-step operation within 110 min, among them, eight compounds with acceptable purity were obtained and identified. The purities of β-sitosterol, protopine, allocryptopine, isocorydione, isocorydine, coptisine, berberrubine, and berberine were 94.7, 96.5, 97.9, 86.6, 98.9, 97.6, 95.7, and 92.8%, respectively.

  12. Ultrafiltration liquid chromatography combined with high-speed countercurrent chromatography for screening and isolating potential α-glucosidase and xanthine oxidase inhibitors from Cortex Phellodendri.

    Science.gov (United States)

    Li, Sainan; Liu, Chunming; Guo, Liping; Zhang, Yuchi; Wang, Jing; Ma, Bing; Wang, Yueqi; Wang, Yumeng; Ren, Junqi; Yang, Xiaojing; Qin, Yao; Tang, Ying

    2014-09-01

    Cortex Phellodendri is a typical Chinese herb with a large number of alkaloids existing in all parts of it. The most common methods for screening and isolating alkaloids are mostly labor intensive and time consuming. In this study, a new assay based upon ultrafiltration liquid chromatography was developed for the rapid screening of ligands for α-glucosidase and xanthine oxidase. The C. Phellodendri extract was found to contain two alkaloids with both α-glucosidase- and xanthine oxidase binding activities and one lactone with α-glucosidase-binding activity. Subsequently, with the help of high-speed countercurrent chromatography, the specific binding ligands including palmatine, berberine, and obaculactone with purities of 97.38, 96.12, and 96.08%, respectively, were successfully separated. An optimized low-toxicity two-phase solvent system composed of ethyl acetate/n-butanol/ethanol/water (3.5:1.7:0.5:5, v/v/v/v) was used to isolate the three compounds mentioned above from C. Phellodendri. The targeted compounds were identified by liquid chromatography coupled with mass spectrometry and NMR spectroscopy. Therefore, ultrafiltration liquid chromatography combined with high-speed countercurrent chromatography is not only a powerful tool for screening and isolating α-glucosidase and xanthine oxidase inhibitors in complex samples but is also a useful platform for discovering bioactive compounds for the prevention and treatment of diabetes mellitus and gout.

  13. An in-situ Observation on Initial Aggregation Process of Colloidal Particles near Three-Phase Contact Line of Air, Water and Vertical Substrate

    Institute of Scientific and Technical Information of China (English)

    YAO Can; WANG Yu-Ren; LAN Ding; DUAN Li; KANG Qi

    2008-01-01

    The self-assembling process near the three-phase contact line of air, water and vertical substrate is widely used to produce various kinds of nanostructured materials and devices. We perform an in-situ observation on the selfassembling process in the vicinity of the three phase contact line. Three kinds of aggregations, i.e. particle-particle aggregation, particle-chain aggregation and chain-chain aggregation, in the initial stage of vertical deposition process are revealed by our experiments. It is found that the particle-particle aggregation and the particle-chain aggregation can be qualitatively explained by the theory of the capillary immersion force and mirror image force,while the chain-chain aggregation leaves an opening question for the further studies. The present study may provide more deep insight into the self-assembling process of colloidal particles.

  14. Adsorption at air-water and oil-water interfaces and self-assembly in aqueous solution of ethoxylated polysorbate nonionic surfactants.

    Science.gov (United States)

    Penfold, Jeffrey; Thomas, Robert K; Li, Peixun X; Petkov, Jordan T; Tucker, Ian; Webster, John R P; Terry, Ann E

    2015-03-17

    The Tween nonionic surfactants are ethoxylated sorbitan esters, which have 20 ethylene oxide groups attached to the sorbitan headgroup and a single alkyl chain, lauryl, palmityl, stearyl, or oleyl. They are an important class of surfactants that are extensively used in emulsion and foam stabilization and in applications associated with foods, cosmetics and pharmaceuticals. A range of ethoxylated polysorbate surfactants, with differing degrees of ethoxylation from 3 to 50 ethylene oxide groups, have been synthesized and characterized by neutron reflection, small-angle neutron scattering, and surface tension. In conjunction with different alkyl chain groups, this provides the opportunity to modify their surface properties, their self-assembly in solution, and their interaction with macromolecules, such as proteins. Adsorption at the air-water and oil-water interfaces and solution self-assembly of the range of ethoxylated polysorbate surfactants synthesized are presented and discussed.

  15. Adaptive chemistry of bifunctional gold nanoparticles at the air/water interface. A synchrotron X-ray study of giant amphiphiles

    DEFF Research Database (Denmark)

    Nørgaard, K.; Weygand, M.J.; Kjær, K.

    2004-01-01

    A series of ligand stabilized gold nanoparticles with diameters close to 3 nm were studied as Langmuir monolayers at the air/water interface by synchrotron X-ray diffraction and reflectivity. Alkylthiols with different length and/or terminal functional group (hydrophilic or hydrophobic) were...... of environmental responsiveness, as they adapt to an amphiphilic distribution of ligands around the gold core when spread at the water surface. Likewise nanoparticles of mixed long and short alkyl chains respond to lateral pressure by adopting a structure where the short alkyl chains determine the in-plane nearest...... introduced into the ligand shell by ligand place exchange reactions. Synchrotron grazing incidence X-ray diffraction (GIXD) and specular X-ray reflectivity reveal the well known hexagonally packed monolayers. In addition the mixed hydrophilic/ hydrophobic ligand shell nanoparticles show a high degree...

  16. Two-photon excitation of surface plasmon and the period-increasing effect of low spatial frequency ripples on a GaP crystal in air/water

    Science.gov (United States)

    Liu, Jukun; Jia, Tianqing; Zhao, Hongwei; Huang, Yaoqing

    2016-11-01

    We report the period-increasing effect of low spatial frequency ripples on a GaP crystal irradiated by 1 kHz, 50 fs, 800 nm femtosecond laser pulses. Massive free electrons are excited by a two-photon absorption process and surface plasmon is excited. The Drude model is used to estimate the changing of the dielectric constant of the GaP crystal. The period-increasing effects of low spatial frequency laser-induced ripples are theoretically predicted in air/water, and the experimental results agree well. The experimental and theoretical results indicate that surface plasmon excited by two-photon absorption plays a key role in the formation of low spatial frequency ripples.

  17. In situ air-water and particle-water partitioning of perfluorocarboxylic acids, perfluorosulfonic acids and perfluorooctyl sulfonamide at a wastewater treatment plant.

    Science.gov (United States)

    Vierke, Lena; Ahrens, Lutz; Shoeib, Mahiba; Palm, Wolf-Ulrich; Webster, Eva M; Ellis, David A; Ebinghaus, Ralf; Harner, Tom

    2013-08-01

    In situ measurements of air and water phases at a wastewater treatment plant (WWTP) were used to investigate the partitioning behavior of perfluorocarboxylic acids (PFCAs), perfluorosulfonic acids (PFSAs) and perfluorooctyl sulfonamide (HFOSA) and their conjugate bases (PFC(-)s, PFS(-)s, and FOSA(-), respectively). Particle-dissolved (Rd) and air-water (QAW) concentration ratios were determined at different tanks of a WWTP. Sum of concentrations of C4-12,14 PFC(A)s, C4,6,8,10 PFS(A)s and (H)FOSA were as high as 50 pg m(-3) (atmospheric gas phase), 2300 ng L(-1) (aqueous dissolved phase) and 2500 ng L(-1) (aqueous particle phase). Particle-dissolved concentration ratios of total species, log Rd, ranged from -2.9 to 1.3 for PFS(A)s, from -1.9 to 1.1 for PFC(A)s and was 0.71 for (H)FOSA. These field-based values agree well with equilibrium partitioning data reported in the literature, suggesting that any in situ generation from precursors, if they are present in this system, occurs at a slower rate than the rate of approach to equilibrium. Acid QAW were also estimated. Good agreement between the QAW and the air-water equilibrium partition coefficient for C8PFCA suggests that the air above the WWTP tanks is at or near equilibrium with the water. Uncertainties in these QAW values are attributed mainly to variability in pKa values reported in the literature. The WWTP provides a unique environment for investigating environmental fate processes of the PFCAs and PFSAs under 'real' conditions in order to better understand and predict their fate in the environment.

  18. Adenovirus purification by two-column, size-exclusion, simulated countercurrent chromatography.

    Science.gov (United States)

    Nestola, Piergiuseppe; Silva, Ricardo J S; Peixoto, Cristina; Alves, Paula M; Carrondo, Manuel J T; Mota, José P B

    2014-06-20

    Adenovirus serotype 5 (Ad5) was successfully separated by size-exclusion chromatography (SEC) using a simple, yet efficient, two-column, quasi-continuous, simulated moving-bed process operated in an open-loop configuration. The operating cycle is divided into two identical half-cycles, each of them consisting of the following sequence of sub-steps: (i) elution of the upstream column and direction of the effluent of the downstream column to waste; (ii) elution of the upstream column and redirection of its effluent to waste while the downstream column is fed with the clarified bioreaction bulk and its effluent collected as purified product; (iii) operation of the system as in step (i) but collecting the effluent of the downstream column as product; (iv) elution of the upstream column and direction of its effluent to waste while the flow through the downstream column is temporarily halted. Clearance of impurities, namely DNA and host cell protein (HCP), were experimentally assessed. The pilot-scale run yielded a virus recovery of 86%, and a clearance of 90% and 89% for DNA and HCP, respectively, without any fine tunning of the predetermined operating parameters. These figures compare very favorably against single-column batch chromatography for the same volume of size-exclusion resin. However, and most importantly, the virus yield was increased from 57% for the batch system to 86% for the two-column SEC process because of internal recycling of the mixed fractions of contaminated Ad5, even though the two-column process was operated strictly in an open-loop configuration. And last, but not least, the productivity was increased by 6-fold with the two-column process. In conclusion, the main drawbacks of size-exclusion chromatography, namely low productivity and low product titer, were overcome to a considerable extent by an innovative two-column configuration that keeps the mixed fractions inside the system at all times.

  19. Two-Phase Flow Hydrodynamics in Superhydrophobic Channels

    Science.gov (United States)

    Stevens, Kimberly; Crockett, Julie; Maynes, Daniel; Iverson, Brian

    2015-11-01

    Superhydrophobic surfaces promote drop-wise condensation and droplet removal leading to the potential for increased thermal transport. Accordingly, great interest exists in using superhydrophobic surfaces in flow condensing environments, such as power generation and desalination. Adiabatic air-water mixtures were used to gain insight into the effect of hydrophobicity on two-phase flows and the hydrodynamics present in flow condensation. Pressure drop and onset of various flow regimes in hydrophilic, hydrophobic, and superhydrophobic mini (0.5 x 10 mm) channels were explored. Data for air/water mixtures with superficial Reynolds numbers from 20-200 and 250-1800, respectively, were obtained. Agreement between experimentally obtained pressure drops and correlations in literature for the conventional smooth control surfaces was better than 20 percent. Transitions between flow regimes for the hydrophobic and hydrophilic channels were similar to commonly recognized flow types. However, the superhydrophobic channel demonstrated significantly different flow regime behavior from conventional surfaces including a different shape of the air slugs, as discussed in the presentation.

  20. Separation of polar betalain pigments from cacti fruits of Hylocereus polyrhizus by ion-pair high-speed countercurrent chromatography.

    Science.gov (United States)

    Wybraniec, Sławomir; Stalica, Paweł; Jerz, Gerold; Klose, Bettina; Gebers, Nadine; Winterhalter, Peter; Spórna, Aneta; Szaleniec, Maciej; Mizrahi, Yosef

    2009-10-09

    Polar betacyanin pigments together with betaxanthins from ripe cactus fruits of Hylocereus polyrhizus (Cactaceae) were fractionated by means of preparative ion-pair high-speed countercurrent chromatography (IP-HSCCC) also using the elution-extrusion (EE) approach for a complete pigment recovery. HSCCC separations were operated in the classical 'head-to-tail' mode with an aqueous mobile phase. Different CCC solvent systems were evaluated in respect of influence and effectiveness of fractionation capabilities to separate the occurring pigment profile of H. polyrhizus. For that reason, the additions of two different volatile ion-pair forming perfluorinated carboxylic acids (PFCA) were investigated. For a direct comparison, five samples of Hylocereus pigment extract were run on preparative scale (900 mg) in 1-butanol-acetonitrile-aqueous TFA 0.7% (5:1:6, v/v/v) and the modified systems tert.-butyl methyl ether-1-butanol-acetonitrile-aqueous PFCA (2:2:1:5, v/v/v/v) using 0.7% and 1.0% trifluoroacetic acid (TFA) or heptafluorobutyric acid (HFBA) in the aqueous phase, respectively. The chemical affinity to the organic stationary CCC solvent phases and in consequence the retention of these highly polar betalain pigments was significantly increased by the use of the more lipophilic fluorinated ion-pair reagent HFBA instead of TFA. The HFBA additions separated more effectively the typical cacti pigments phyllocactin and hylocerenin from betanin as well as their iso-forms. Unfortunately, similar K(D) ratios and selectivity factors alpha around 1.0-1.1 in all tested solvent systems proved that the corresponding diastereomers, 15S-type pigments cannot be resolved from the 15R-epimers (iso-forms). Surprisingly, additions of the stronger ion-pair reagent (HFBA) resulted in a partial separation of hylocerenin from phyllocactin which were not resolved in the other solvent systems. The pigments were detected by means of HPLC-DAD and HPLC-electrospray ionization-MS using also

  1. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    Energy Technology Data Exchange (ETDEWEB)

    Yortsos, Yanis C.

    2001-08-07

    This project is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  2. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    Energy Technology Data Exchange (ETDEWEB)

    Yortsos, Y.C.

    2001-05-29

    This report is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  3. A Twophase Multirate-Mass Transfer Model for Flow and Transport in Porous Media

    Science.gov (United States)

    Dentz, M.; Tecklenburg, J.; Neuweiler, I.; Carrera, J.

    2015-12-01

    We present an upscaled non-local model for two-phase flow and transport in highly heterogeneous porous media. The media under consideration are characterized by sharp contrasts in the hydraulic properties typical for fractured porous media, for example. A two-scale expansion gives an upscaled flow and transport formulation that models multiratemass transfer between mobile (fracture) and immobile (matrix) medium portions. The evolution of saturation due to viscous dominated flow in the mobile domain and mass exchange with the immobile zones through capillary countercurrent flow. The medium heterogeneity is mapped onto the mass transfer parameters, which are encoded in a memory functionthat describes the non-local flux between mobile and immobile zones. The upscaled model is parameterized by the medium heterogeneity and the distribution of hydraulic parameters. Breakthrough of the displaced fluidshows characteristic heavy tails due to fluid retention in immobile zones.

  4. Target-guided separation of Bougainvillea glabra betacyanins by direct coupling of preparative ion-pair high-speed countercurrent chromatography and electrospray ionization mass-spectrometry.

    Science.gov (United States)

    Jerz, Gerold; Wybraniec, Sławomir; Gebers, Nadine; Winterhalter, Peter

    2010-07-02

    In this study, preparative ion-pair high-speed countercurrent chromatography was directly coupled to an electrospray ionization mass-spectrometry device (IP-HSCCC/ESI-MS-MS) for target-guided fractionation of high molecular weight acyl-oligosaccharide linked betacyanins from purple bracts of Bougainvillea glabra (Nyctaginaceae). The direct identification of six principal acyl-oligosaccharide linked betacyanins in the mass range between m/z 859 and m/z 1359 was achieved by positive ESI-MS ionization and gave access to the genuine pigment profile already during the proceeding of the preparative separation. Inclusively, all MS/MS-fragmentation data were provided during the chromatographic run for a complete analysis of substitution pattern. On-line purity evaluation of the recovered fractions is of high value in target-guided screening procedures and for immediate decisions about suitable fractions used for further structural analysis. The applied preparative hyphenation was shown to be a versatile screening method for on-line monitoring of countercurrent chromatographic separations of polar crude pigment extracts and also traced some minor concentrated compounds. For the separation of 760mg crude pigment extract the biphasic solvent system tert.-butylmethylether/n-butanol/acetonitrile/water 2:2:1:5 (v/v/v/v) was used with addition of ion-pair forming reagent trifluoroacetic acid. The preparative HSCCC-eluate had to be modified by post-column addition of a make-up solvent stream containing formic acid to reduce ion-suppression caused by trifluoroacetic acid and later significantly maximized response of ESI-MS/MS detection of target substances. A variable low-pressure split-unit guided a micro-eluate to the ESI-MS-interface for sensitive and direct on-line detection, and the major volume of the effluent stream was directed to the fraction collector for preparative sample recovery. The applied make-up solvent mixture significantly improved smoothness of the continuously

  5. Korea advanced liquid metal reactor development - Development of measuring techniques of the sodium two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moo Hwan; Cha, Jae Eun [Pohang University of Science and Technology, Pohang (Korea)

    2000-04-01

    The technology which models and measures the behavior of bubble in liquid sodium is very important to insure the safety of the liquid metal reactor. In this research, we designed/ manufactured each part and loop of experimental facility for sodium two phase flow, and applied a few possible methods, measured characteristic of two phase flow such as bubbly flow. A air-water loop similar to sodium loop on each measuring condition was designed/manufactured. This air-water loop was utilized to acquire many informations which were necessary in designing the two phase flow of sodium and manufacturing experimental facility. Before the manufacture of a electromagnetic flow meter for sodium, the experiment using each electromagnetic flow mete was developed and the air-water loop was performed to understand flow characteristics. Experiments for observing the signal characteristics of flow were performed by flowing two phase mixture into the electromagnetic flow mete. From these experiments, the electromagnetic flow meter was designed and constructed by virtual electrode, its signal processing circuit and micro electro magnet. It was developed to be applicable to low conductivity fluid very successfully. By this experiment with the electromagnetic flow meter, we observed that the flow signal was very different according to void fraction in two phase flow and that probability density function which was made by statistical signal treatment is also different according to flow patterns. From this result, we confirmed that the electromagnetic flow meter could be used to understand the parameters of two phase flow of sodium. By this study, the experimental facility for two phase flow of sodium was constricted. Also the new electromagnetic flow meter was designed/manufactured, and experimental apparatus for two phase flow of air-water. Finally, this study will be a basic tool for measurement of two phase flow of sodium. As the fundamental technique for the applications of sodium at

  6. RE-AERATION LAW OF WATER FLOW OVER SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang-ju; LUO Lin; CHEN Yong-can; ZHAO Wen-qian

    2006-01-01

    In order to explore the re-aeration law of water flow over spillway, the transfer process of oxygen in water flow over spillway was studied. The interfacial mass transfer coefficients were obtained by experiments. The flow fields and the turbulence characteristics are simulated by numerical methods. The fractional volume of fluid model (VOF) of the air-water two phase flows was introduced to track the interface. Consequently, the quantitative expression of the interfacial mass transfer coefficients related with velocity and kinetic energy at the free surface was derived and the re-aeration model for the water flow over spillway was established. The examination with the experimental data of different conditions shows the validity of the re-aeration model for the water flow over spillways. This study will be important to evaluate the dissolved oxygen concentration and self-purification ability of rivers.

  7. Self-aggregation Phenomenon and Stable Flow Conditions in a Two-Phase Flow Through a Minichannel

    Science.gov (United States)

    Górski, Grzegorz; Litak, Grzegorz; Mosdorf, Romuald; Rysak, Andrzej

    2015-10-01

    By increasing a water flow rate of the two-phase (air-water) flow through a minichannel, both the partitioning of air slugs into air bubbles of different sizes and small air bubbles aggregation into larger air bubbles were identified. These phenomena were studied in detail by using the corresponding sequences of light transmission time series recorded with a laser-phototransistor sensor. To distinguish any instabilities in air slugs along with their break-ups and aggregations, the recurrence plots and recurrence quantification analysis were applied.

  8. An Eulerian-Lagrangian open source solver for bubbly flow in vertical pipes

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Monferrer, C.; Munoz-Cobo, J. L.; Monros-Andreu, G.; Martinez-Cuenca, R.; Chiva, S.

    2014-07-01

    Air-water two-phase flow is present in natural and industrial processes of different nature as nuclear reactors. An accurate local prediction of the boiling flow could support safety and operation analyses of nuclear reactors. An Eulerian-Lagrangian approach is investigated in this contribution as it can be used as a virtual facility to investigate the two-phase flow phenomena. A solver based on the PISO algorithm coupled with the Lagrangian equation of motion have been implemented for computing incompressible bubbly flows. (Author)

  9. Towards a unified picture of the water self-ions at the air-water interface: a density functional theory perspective

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Marcel D.; Kuo, I-F W.; Tobias, Douglas J.; Mundy, Christopher J.

    2014-07-17

    The propensities of the water self ions, H3O+ and OH- , for the air-water interface has implications for interfacial acid-base chemistry. Despite numerous experimental and computational studies, no consensus has been reached on the question of whether or not H3O+ and/or OH- prefer to be at the water surface or in the bulk. Here we report a molecular dynamics simulation study of the bulk vs. interfacial behavior of H3O+ and OH- that employs forces derived from density functional theory with a generalized gradient approximation exchangecorrelation functional (specifically, BLYP) and empirical dispersion corrections. We computed the potential of mean force (PMF) for H3O+ as a function of the position of the ion in a 215-molecule water slab. The PMF is flat, suggesting that H3O+ has equal propensity for the air-water interface and the bulk. We compare the PMF for H3O+ to our previously computed PMF for OH- adsorption, which contains a shallow minimum at the interface, and we explore how differences in solvation of each ion at the interface vs. the bulk are connected with interfacial propensity. We find that the solvation shell of H3O+ is only slightly dependent on its position in the water slab, while OH- partially desolvates as it approaches the interface, and we examine how this difference in solvation behavior is manifested in the electronic structure and chemistry of the two ions. DJT was supported by National Science Foundation grant CHE-0909227. CJM was supported by the U.S. Department of Energy‘s (DOE) Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the Department of Energy by Battelle. The potential of mean force required resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DEAC05-00OR22725. The remaining simulations

  10. Effects of the conjugation of whey proteins with gellan polysaccharides on surfactant-induced competitive displacement from the air-water interface.

    Science.gov (United States)

    Cai, B; Ikeda, S

    2016-08-01

    Whey proteins can be used to stabilize foams and emulsions against coalescence because of their ability to form viscoelastic films at the interface that resist film rupture on collision between colloidal particles. However, whey proteins are competitively displaced from the interface if small-molecule surfactants are added, leading to destabilization of the entire system. This is because surfactants are more effective in molecular packing at the interface, and they lower interfacial tension to a greater degree than whey proteins do, but their interfacial films are poor in viscoelasticity. We hypothesized that whey proteins would become more resistant to surfactant-induced competitive displacement if they were conjugated with network-forming polysaccharides. The protein moiety of the conjugate would be expected to enable its adsorption to the interface, and the polysaccharide moiety would be expected to form self-assembled networks, strengthening the interfacial film as a whole. In this study, whey proteins were conjugated with gellan polysaccharides using the Maillard reaction. Atomic force microscopy images of interfacial films formed by the whey protein-gellan conjugate at the air-water interface and transferred onto mica sheets using the Langmuir-Blodgett method revealed that gellan did form self-assembled networks at the interface and that interfacial films also contained a large number of unconjugated whey protein molecules. Following the addition of a small-molecule surfactant (Tween 20) to the sub-phase, surface pressure increased, indicating spontaneous adsorption of surfactants to the interface. Atomic force microscopy images showed decreases in interfacial area coverage by whey proteins as surface pressure increased. At a given surface pressure, the interfacial area coverage by whey protein-gellan conjugates was greater than coverage by unconjugated whey proteins, confirming that whey proteins became more resistant to surfactant-induced displacement after

  11. Detailed flow and force measurements in a rotated triangular tube bundle subjected to two-phase cross-flow

    Science.gov (United States)

    Pettigrew, M. J.; Zhang, C.; Mureithi, N. W.; Pamfil, D.

    2005-05-01

    Two-phase cross-flow exists in many shell-and-tube heat exchangers. A detailed knowledge of the characteristics of two-phase cross-flow in tube bundles is required to understand and formulate flow-induced vibration parameters such as damping, fluidelastic instability, and random excitation due to turbulence. An experimental program was undertaken with a rotated-triangular array of cylinders subjected to air/water flow to simulate two-phase mixtures. The array is made of relatively large diameter cylinders (38 mm) to allow for detailed two-phase flow measurements between cylinders. Fiber-optic probes were developed to measure local void fraction. Local flow velocities and bubble diameters or characteristic lengths of the two-phase mixture are obtained by using double probes. Both the dynamic lift and drag forces were measured with a strain gauge instrumented cylinder.

  12. Purification of six lignans from the stems of Schisandra chinensis by using high-speed counter-current chromatography combined with preparative high-performance liquid chromatography.

    Science.gov (United States)

    Zhu, Lijie; Li, Bin; Liu, Xiuying; Huang, Guohui; Meng, Xianjun

    2015-11-01

    A method for the preparative purification of lignans from Schisandra chinensis was established using a combination of high-speed counter-current chromatography (HSCCC) and preparative high-performance liquid chromatography (HPLC). The crude extracts obtained from S. chinensis by using 70% ethanol were separated on a macroporous resin column and then eluted with a graded ethanol series. A two-phase solvent system consisting of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v) was used for HSCCC, and a mobile phase of acetonitrile-water (50:50, v/v) was used for preparative HPLC. The results obtained using HSCCC were compared with those obtained using preparative HPLC, and their advantages were further integrated to improve the separation efficiency. Six known lignans were identified by electrospray ionisation mass spectrometry and (1)H nuclear magnetic resonance (NMR) and (13)C NMR analyses; the purities of all the compounds were more than 91%.

  13. Separation of three anthraquinone glycosides including two isomers by preparative high-performance liquid chromatography and high-speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf.

    Science.gov (United States)

    Chen, Tao; Li, Hongmei; Zou, Denglang; Liu, Yongling; Chen, Chen; Zhou, Guoying; Li, Yulin

    2016-08-01

    Anthraquinone glycosides, such as chrysophanol 1-O-β-d-glucoside, chrysophanol 8-O-β-d-glucoside, and physion 8-O-β-d-glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above-mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1-O-β-d-glucoside and chrysophanol 8-O-β-d-glucoside. This study demonstrated an efficient strategy based on preparative high-performance liquid chromatography and high-speed countercurrent chromatography for the separation of the above-mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf.

  14. Extraction and isolation of dictamnine, obacunone and fraxinellone from Dictamnus dasycarpus Turcz. by supercritical fluid extraction and high-speed counter-current chromatography

    Directory of Open Access Journals (Sweden)

    Daijie Wang

    2012-01-01

    Full Text Available Supercritical fluid extraction was used to extract active compounds from the Chinese traditional medicinal D. dasycarpus under the pressure of 30 MPa and temperature of 45 ºC. Further separation and purification was established by high-speed counter-current chromatography (HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.8:1.3:0.9, volume ratio. The separation yielded a total of 47 mg of dictamnine, 24 mg of obacunone and 83 mg of fraxinellone from 1.0 g of the crude extract in one step separation with the purity of 99.2, 98.4 and 99.0%, respectively, as determined by HPLC. The chemical structures of these compounds were identified by ESI-MS, IR, ¹H-NMR and 13C-NMR.

  15. Preparative separation of C{sub 19}-diterpenoid alkaloids from Aconitum carmichaelii Debx by pH zone-refining counter-current chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dahui [Institute of Medicinal Plants, Yunnan Academy of Agricultural Sciences, Kunming (China); Shu, Xikai; Wang, Xiao; Fang, Lei; Huang, Luqi, E-mail: wxjn1998@126.com [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China); Xi, Xingjun; Zheng, Zhenjia [China National institute of Standardization, Beijing (China)

    2013-11-01

    The technique of pH-zone-refining counter-current chromatography was successfully applied to preparatively separate three C{sub 19}-diterpenoid alkaloids from the crude extracts of Aconitum carmichaelii for the first time using a two-phase solvent system of petroleum ether-ethyl acetate-methanol-water (5:5:1:9, v/v/v/v). Mesaconitine (I), hypaconitine (II), and deoxyaconitine (III) were obtained from 2.5 g of the crude alkaloids in a one-step separation; the yields were 4.16%, 16.96%, and 5.05%, respectively. The purities of compounds I, II, and III were 93.0%, 95%, and 96%, respectively, as determined by HPLC. The chemical structures of the three compounds were identified by electrospray ionization mass spectrometry (ESI-MS) and NMR. (author)

  16. Preparative separation and purification of bufadienolides from ChanSu by high-speed counter-current chromatography combined with preparative HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jialian; Zhang, Yongqing, E-mail: fleiv@163.com [College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, Shandong (China); Lin, Yunliang; Wang, Xiao; Fang, Lei; Geng, Yanling [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China); Zhang, Qinde [Shandong College of Traditional Chinese Medicine, Laiyang, Shandong (China)

    2013-09-01

    Eight bufadienolides were successfully isolated and purified from ChanSu by high-speed counter-current chromatography (HSCCC) combined with preparative HPLC (prep-HPLC). First, a stepwise elution mode of HSCCC with the solvent system composed of petroleum ether-ethyl acetate-methanol-water (4:6:4:6, 4:6:5:5, v/v) was employed and four bufadienolides, two partially purified fractions were obtained from 200 mg of crude extract. The partially purified fractions III and VI were then further separated by prepHPLC, respectively, and another four bufadienolides were recovered. Their structures were confirmed by ESI-MS and {sup 1}H-NMR spectra. (author)

  17. Application of preparative high-speed counter-current chromatography for isolation and separation of schizandrin and gomisin A from Schisandra chinensis.

    Science.gov (United States)

    Peng, Jinyong; Fan, Guorong; Qu, Liping; Zhou, Xin; Wu, Yutian

    2005-08-05

    Following an initial cleaning-up step on the D101 macroporous resin, a preparative high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.9:0.9:1, v/v) was used to isolate and separate schizandrin and gomisin A from Schisandra chinensis. A total of 107 mg schizandrin and 36 mg gomisin A with purities of 99.5% and 99.1% were obtained from 400 mg crude extract in one-step elution and less than 3 h, and the structure identification was performed by UV, IR, MS, 1H NMR and 13C NMR.

  18. Separation and purification of three stilbenes from the radix of Polygonum cillinerve (Nakai Ohwl by macroporous resin column chromatography combined with high-speed counter-current chromatography

    Directory of Open Access Journals (Sweden)

    Xiaofeng Chi

    2014-01-01

    Full Text Available An effective method for the rapid separation and purification of three stilbenes from the radix of Polygonum cillinerve (Nakai Ohwl by macroporous resin column chromatography combined with high-speed counter-current chromatography (HSCCC was successfully established. In the present study, a two-phase solvent system composed of chloroform-n-butanol-methanol-water (4:1:4:2, v/v/v/v was used for HSCCC separation. A one-step separation in 4 h from 150 mg of crude extract produced 26.3 mg of trans-resveratrol-3-O-glucoside, 42.0 mg of pieceid-2"-O-gallate, and 17.9 mg of trans-resveratrol with purities of 99.1%, 97.8%, and 99.4%, respectively, as determined by high-performance liquid chromatography (HPLC. The chemical structures of these compounds were identified by nuclear magnetic resonance (NMR spectroscopy.

  19. Preparative isolation and purification of harpagoside and angroside C from the root of Scrophularia ningpoensis Hemsley by high-speed counter-current chromatography.

    Science.gov (United States)

    Tian, Jinfeng; Ye, Xiaoli; Shang, Yuanhong; Deng, Yafei; He, Kai; Li, Xuegang

    2012-10-01

    In this study, the bioactive component harpagoside and angroside C in the root of Scrophularia ningpoensis Hemsley was simultaneously separated by high-speed counter-current chromatography (HSCCC). A two-phase solvent system containing chloroform/n-butanol/methanol/water (4:1:3:2, v/v/v/v) was selected following consideration of the partition coefficient of the target compound. The crude extract (200 mg) was loaded onto a 280-mL HSCCC column and yielded 22 mg harpagoside and 31 mg angroside C with the purity of higher than 98 and 98.5%, respectively. It is feasible to isolate active compounds harpagoside and angroside C from S. ningpoensis using HSCCC.

  20. Comprehensive separation of secondary metabolites in natural products by high-speed counter-current chromatography using a three-phase solvent system.

    Science.gov (United States)

    Yanagida, Akio; Yamakawa, Yutaka; Noji, Ryoko; Oda, Ako; Shindo, Heisaburo; Ito, Yoichiro; Shibusawa, Yoichi

    2007-06-01

    High-speed counter-current chromatography (HSCCC) using the three-phase solvent system n-hexane-methyl acetate-acetonitrile-water at a volume ratio of 4:4:3:4 was applied to the comprehensive separation of secondary metabolites in several natural product extracts. A wide variety of secondary metabolites in each natural product was effectively extracted with the three-phase solvent system, and the filtered extract was directly submitted to the HSCCC separation using the same three-phase system. In the HSCCC profiles of crude natural drugs listed in the Japanese Pharmacopoeia, several physiologically active compounds were clearly separated from other components in the extracts. The HSCCC profiles of several tea products, each manufactured by a different process, clearly showed their compositional difference in main compounds such as catechins, caffeine, and pigments. These HSCCC profiles also provide useful information about hydrophobic diversity of whole components present in each natural product.

  1. Preparative Isolation and Purification of Four Compounds from Cistanches deserticola Y.C. Ma by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Lifeng Han

    2012-07-01

    Full Text Available Following a constituent enrichment step on a silica gel column, four phenyl-ethanoid glycosides were successfully isolated from Cistanches deserticola and purified by preparative high-speed counter-current chromatography (HSCCC with a two-phase solvent system composed of ethyl acetate-n-butanol-ethanol-water (40:6:6:50, v/v/v/v. A total of 30.9 mg acteoside, 13.0 mg isoacteoside, 12.5 mg syringalide A 3'-α-L-rhamnopyranoside and 7.2 mg 2'-acetylacteoside with purity of higher than 95%, as determined by HPLC-ELSD, were obtained in one-step separation from 297 mg of Cistanche deserticola extract, respectively. Their structures were identified by HR-MS, 1H-NMR and 13C-NMR.

  2. Using quantitative structure activity relationship models to predict an appropriate solvent system from a common solvent system family for countercurrent chromatography separation.

    Science.gov (United States)

    Marsden-Jones, Siân; Colclough, Nicola; Garrard, Ian; Sumner, Neil; Ignatova, Svetlana

    2015-06-12

    Countercurrent chromatography (CCC) is a form of liquid-liquid chromatography. It works by running one immiscible solvent (mobile phase) over another solvent (stationary phase) being held in a CCC column using centrifugal force. The concentration of compound in each phase is characterised by the partition coefficient (Kd), which is the concentration in the stationary phase divided by the concentration in the mobile phase. When Kd is between approximately 0.2 and 2, it is most likely that optimal separation will be achieved. Having the Kd in this range allows the compound enough time in the column to be separated without resulting in a broad peak and long run time. In this paper we report the development of quantitative structure activity relationship (QSAR) models to predict logKd. The QSAR models use only the molecule's 2D structure to predict the molecular property logKd.

  3. Separation of five flavonoids from tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) grains via off-line two dimensional high-speed counter-current chromatography.

    Science.gov (United States)

    Jiang, Shujing; Liu, Qi; Xie, Yixi; Zeng, Hualiang; Zhang, Li; Jiang, Xinyu; Chen, Xiaoqing

    2015-11-01

    An off-line two dimensional (2D) high-speed counter-current chromatography (HSCCC) strategy was successfully used for preparative separation of five flavonoids from tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) grains with different solvent systems for the first time in this paper. n-Hexane-ethyl acetate-methanol-water 3:5:3:5 (v/v) was selected as the first dimension solvent system to purify quercetin (4) and kaempferol (5). The second dimension solvent system, ethyl acetate-n-butanol-water 7:3:10 (v/v), was used to isolate quercetin 3-O-rutinoside-3'-O-β-glucopyranoside (1), rutin (2) and kaempferol 3-rutinoside (3). The purities of these compounds were all above 96.0% and their structures were identified through UV, MS and (1)H NMR. The results indicated that the off-line 2D HSCCC is an efficient technique to isolate flavonoids compounds from grains.

  4. Extraction and isolation of dictamnine, obacunone and fraxinellone from Dictamnus dasycarpus Turcz. by supercritical fluid extraction and high-speed counter-current chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Daijie; Lin, Yunliang; Lin, Xiaojing; Geng, Yanling; Wang, Xiao, E-mail: wxjn1998@126.com [Process Control Research Center of TCM. Shandong Academy of Sciences. Shandong Analysis and Test Center (China); Zhang, Jinjie [College of Biosystems Engineering and Food Science, Zhejiang University (China); Qiu, Jiying [Institute of Agro-Food Science and Technology, Shandong Academy of Agricultural Science, Shandong (China)

    2012-07-01

    Supercritical fluid extraction was used to extract active compounds from the Chinese traditional medicinal D. dasycarpus under the pressure of 30 MPa and temperature of 45 degree C. Further separation and purification was established by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.8:1.3:0.9, volume ratio). The separation yielded a total of 47 mg of dictamnine, 24 mg of obacunone and 83 mg of fraxinellone from 1.0 g of the crude extract in one step separation with the purity of 99.2, 98.4 and 99.0%, respectively, as determined by HPLC. The chemical structures of these compounds were identified by ESI-MS, IR, 1H-NMR and {sup 13}C-NMR. (author)

  5. Interfacial area transport in bubbly flow

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, M.; Wu, Q.; Revankar, S.T. [Purdue Univ., West Lafayette, IN (United States)] [and others

    1997-12-31

    In order to close the two-fluid model for two-phase flow analyses, the interfacial area concentration needs to be modeled as a constitutive relation. In this study, the focus was on the investigation of the interfacial area concentration transport phenomena, both theoretically and experimentally. The interfacial area concentration transport equation for air-water bubbly up-flow in a vertical pipe was developed, and the models for the source and sink terms were provided. The necessary parameters for the experimental studies were identified, including the local time-averaged void fraction, interfacial area concentration, bubble interfacial velocity, liquid velocity and turbulent intensity. Experiments were performed with air-water mixture at atmospheric pressure. Double-sensor conductivity probe and hot-film probe were employed to measure the identified parameters. With these experimental data, the preliminary model evaluation was carried out for the simplest form of the developed interfacial area transport equation, i.e., the one-dimensional transport equation.

  6. Preparation of salvianolic acid A by the degradation reaction of salvianolic acid B in subcritical water integrated with pH-zone-refining counter-current chromatography.

    Science.gov (United States)

    Li, Huaizhi; Cheng, Yan; Dong, Hongjing; Wang, Xiao; Li, Jia; Gao, Qianshan

    2016-10-14

    Salvianolic acid A is the major bioactive compound in Danshen, however, due to the chemical instability and low content in Danshen, it is difficult to extract amount of salvianolic acid A. Therefore, this study was to establish an effective strategy for obtaining adequate amount of salvianolic acid A, subcritical water extraction was used to degrade salvianolic acid B and prepare salvianolic acid A. Different reaction conditions including temperature, time, concentration and pH value in subcritical water were investigated. Under 40mg/mL of reactant concentration, 180°C of temperature, 4.0 of pH value and 60min of reaction time, the highest yield rate of salvianolic acid A reached 34.86%. Then, the degradation products were successfully separated by pH-zone-refining counter-current chromatography with the solvent system Pet-EtAc-n-BuOH-H2O (2:3:1:9, v/v), where 10mM TFA was added in stationary phase and 10mM NH3·H2O in mobile phase. As a result, a total of 227.3mg of salvianolic acid A at 98.2% purity, 38.9mg of danshensu at 99.3% purity, 9.5mg of salvianolic acid D at 92.7% purity, and 32.8mg of protocatechuic aldehyde at 93.1% purity were obtained from 1.2g degradation products of salvianolic acid B by one-step purification. The results demonstrated that the combinative application of subcritical water and pH-zone-refining counter-current chromatography is a potential technique for the preparative separation of salvianolic acid A from salvianolic acid B.

  7. Sodium dodecyl sulfate-ethoxylated polyethylenimine adsorption at the air-water interface: how the nature of ethoxylation affects the pattern of adsorption.

    Science.gov (United States)

    Batchelor, Stephen N; Tucker, Ian; Petkov, Jordan T; Penfold, Jeffrey; Thomas, Robert K

    2014-08-19

    The strong interaction between ionic surfactants and polyelectrolytes of opposite charge results in enhanced surface adsorption at the air-water interface down to low surfactant concentrations and in some cases in the formation of ordered surface structures. A notable example which exhibits such properties is the mixture of polyethylenimine, PEI, and sodium dodecyl sulfate, SDS. However, the electrostatic interaction, around charge neutralization, between the surfactant and polymer often results in precipitation or coacervation. This can be mitigated for PEI-surfactant mixtures by ethoxylation of the PEI, but this can also result in a weaker surface interaction and a significant reduction in the adsorption. It is shown here that by localizing the ethoxylation of the PEI into discrete regions of the polymer precipitation upon the addition of SDS is suppressed, the strong surface interaction and enhanced adsorption of the polymer-surfactant mixture is retained. The adsorption of SDS in the presence of ethoxylated PEI is greatly enhanced at low SDS concentrations compared to the adsorption for pure SDS. The adsorption is equally pronounced at pH 7 and 10 and is largely independent of the degree of ethoxylation. Surface ordering, more than monolayer adsorption, is observed over a relatively narrow range of SDS concentrations and is most pronounced at pH 10 and for the polymers with the lower degree of ethoxylation. The results show that ethoxylated PEI's reported here provide a suitable route to enhanced surfactant adsorption while retaining favorable solution properties in which precipitation effects are minimized.

  8. Interfacial assembly of cinnamoyl-terminated bolaamphiphiles through the air/water interface: headgroup-dependent assembly, supramolecular nanotube and photochemical sewing.

    Science.gov (United States)

    Liu, Xufei; Wang, Tianyu; Liu, Minghua

    2011-10-06

    A series of cinnamoyl-terminated bolaamphiphiles were synthesized and their assemblies at the air/water interface were investigated. It was found that the assembly behaviour depended on the substituted groups on the cinnamoyl unit. The bolaamphiphile with 4-hydroxycinnamoyl head groups (HCDA) was found to assemble into a supramolecular nanotube, while the others formed only layer-structured films. Moreover, the nanotube formed from HCDA showed supramolecular chirality due to the symmetry breaking. Both the layered films and the nanotubes showed photochemical dimerization upon UV irradiation, which were studied from the UV-Vis, FT-IR spectral and MALDI-TOF MS analysis. Interestingly, such dimerization behavior of the cinnamoyl group could be used to stabilize the nanotube of HCDAvia photochemical sewing. During such a process both the supramolecular chirality and the tubular shapes were kept. Remarkably, such a photochemical sewed chiral nanotube could further induce the chirality of an achiral porphyrin derivative assembled on it, and produced the induced chirality without using any chiral molecules.

  9. Numerical tools to estimate the flux of a gas across the air-water interface and assess the heterogeny of its forcing functions

    Directory of Open Access Journals (Sweden)

    V. M. N. de C. da S. Vieira

    2012-03-01

    Full Text Available A numerical tool was developed for the estimation of gas fluxes across the air water interface. The primary objective is to use it to estimate CO2 fluxes. Nevertheless application to other gases is easily accomplished by changing the values of the parameters related to the physical properties of the gases. A user friendly software was developed allowing to build upon a standard kernel a custom made gas flux model with the preferred parametrizations. These include single or double layer models; several numerical schemes for the effects of wind in the air-side and water-side transfer velocities; the effect of turbulence from current drag with the bottom; and the effects on solubility of water temperature, salinity, air temperature and pressure. It was also developed an analysis which decomposes the difference between the fluxes in a reference situation and in alternative situations into its several forcing functions. This analysis relies on the Taylor expansion of the gas flux model, requiring the numerical estimation of partial derivatives by a multivariate version of the collocation polynomial. Both the flux model and the difference decomposition analysis were tested with data taken from surveys done in the lagoonary system of Ria Formosa, south Portugal, in which the CO2 fluxes were estimated using the IRGA and floating chamber method whereas the CO2 concentrations were estimated using the IRGA and degasification chamber. Observations and estimations show a remarkable fit.

  10. Spread mixed monolayers of deoxycholic and dehydrocholic acids at the air-water interface, effect of subphase pH. Characterization by axisymmetric drop shape analysis.

    Science.gov (United States)

    Messina, Paula V; Fernández-Leyes, Marcos D; Prieto, Gerardo; Ruso, Juan M; Sarmiento, Félix; Schulz, Pablo C

    2008-01-01

    Bile acids (deoxycholic and dehydrocholic acids) spread mixed monolayers behavior at the air/water interface were studied as a function of subphase pH using a constant surface pressure penetration Langmuir balance based on the Axisymmetric Drop Shape Analysis (ADSA). We examined the influence of electrostatic, hydrophobic and hydration forces on the interaction between amphiphilic molecules at the interface by the collapse area values, the thermodynamic parameters and equation of state virial coefficients analysis. The obtained results showed that at neutral (pH=6.7) or basic (pH=10) subphase conditions the collapse areas values are similar to that of cholanoic acid and consistent with the cross-sectional area of the steroid nucleus (approximately 40 A(2)). The Gibbs energy of mixing values (DeltaG(mix) or =1). Such behavior indicates that the polar groups of the molecules interacts each other more strongly by repulsive electrostatic forces than with the more hydrophobic part of the molecule.

  11. A Novel Satellite Mission Concept for Upper Air Water Vapour, Aerosol and Cloud Observations Using Integrated Path Differential Absorption LiDAR Limb Sounding

    Directory of Open Access Journals (Sweden)

    Claudia Weitnauer

    2012-03-01

    Full Text Available We propose a new satellite mission to deliver high quality measurements of upper air water vapour. The concept centres around a LiDAR in limb sounding by occultation geometry, designed to operate as a very long path system for differential absorption measurements. We present a preliminary performance analysis with a system sized to send 75 mJ pulses at 25 Hz at four wavelengths close to 935 nm, to up to 5 microsatellites in a counter-rotating orbit, carrying retroreflectors characterized by a reflected beam divergence of roughly twice the emitted laser beam divergence of 15 µrad. This provides water vapour profiles with a vertical sampling of 110 m; preliminary calculations suggest that the system could detect concentrations of less than 5 ppm. A secondary payload of a fairly conventional medium resolution multispectral radiometer allows wide-swath cloud and aerosol imaging. The total weight and power of the system are estimated at 3 tons and 2,700 W respectively. This novel concept presents significant challenges, including the performance of the lasers in space, the tracking between the main spacecraft and the retroreflectors, the refractive effects of turbulence, and the design of the telescopes to achieve a high signal-to-noise ratio for the high precision measurements. The mission concept was conceived at the Alpbach Summer School 2010.

  12. Prediction of the air-water partition coefficient for perfluoro-2-methyl-3-pentanone using high-level Gaussian-4 composite theoretical methods.

    Science.gov (United States)

    Rayne, Sierra; Forest, Kaya

    2014-09-19

    The air-water partition coefficient (Kaw) of perfluoro-2-methyl-3-pentanone (PFMP) was estimated using the G4MP2/G4 levels of theory and the SMD solvation model. A suite of 31 fluorinated compounds was employed to calibrate the theoretical method. Excellent agreement between experimental and directly calculated Kaw values was obtained for the calibration compounds. The PCM solvation model was found to yield unsatisfactory Kaw estimates for fluorinated compounds at both levels of theory. The HENRYWIN Kaw estimation program also exhibited poor Kaw prediction performance on the training set. Based on the resulting regression equation for the calibration compounds, the G4MP2-SMD method constrained the estimated Kaw of PFMP to the range 5-8 × 10(-6) M atm(-1). The magnitude of this Kaw range indicates almost all PFMP released into the atmosphere or near the land-atmosphere interface will reside in the gas phase, with only minor quantities dissolved in the aqueous phase as the parent compound and/or its hydrate/hydrate conjugate base. Following discharge into aqueous systems not at equilibrium with the atmosphere, significant quantities of PFMP will be present as the dissolved parent compound and/or its hydrate/hydrate conjugate base.

  13. Miscibility of dl-α-tocopherol β-glucoside in DPPC monolayer at air/water and air/solid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Neunert, G. [Department of Physics and Biophysics, Poznan University of Life Sciences, 60-637 Poznan (Poland); Makowiecki, J.; Piosik, E.; Hertmanowski, R. [Faculty of Technical Physics, Poznan University of Technology, 60-965 Poznan (Poland); Polewski, K. [Department of Physics and Biophysics, Poznan University of Life Sciences, 60-637 Poznan (Poland); Martynski, T., E-mail: tomasz.martynski@put.poznan.pl [Faculty of Technical Physics, Poznan University of Technology, 60-965 Poznan (Poland)

    2016-10-01

    The role of newly synthesized tocopherol glycosidic derivative in modifying molecular organization and phase transitions of phospholipid monolayer at the air/water interface has been investigated. Two-component Langmuir films of dl-α-tocopheryl β-D-glucopyranoside (BG) mixed with dipalmitoyl phosphatidylcholine (DPPC) in the whole range of mole fractions were formed at the water surface. An analysis of surface pressure versus mean molecular area (π-A) isotherms and Brewster angle microscope images showed that the presence of BG molecules changes the structure and packing of the DPPC monolayer in a BG concentration dependent manner. BG molecules incorporated into DPPC monolayer inhibit its liquid expanded to liquid condensed phase transition proportionally to the BG concentration. The monolayers were also transferred onto solid substrates and visualized using an atomic force microscope. The results obtained indicate almost complete miscibility of BG and DPPC in the monolayers at surface pressures present in the biological cell membrane (30-35·10{sup -3} N·m{sup -1}) for a BG mole fraction as high as 0.3. This makes the monolayer less packed and more disordered, leading to an increased permeability. The results support our previous molecular dynamics simulation data. - Highlights: • Langmuir films of α-tocopherol derivative with DPPC was studied thermodynamically. • Mixed DPPC/BG films were transferred onto mica substrates for topography imaging by using AFM. • Miscibility of BG/DPPC films at surface pressures present in membranes was observed up to MF = 0.3.

  14. Surface interactions, thermodynamics and topography of binary monolayers of Insulin with dipalmitoylphosphatidylcholine and 1-palmitoyl-2-oleoylphosphatidylcholine at the air/water interface.

    Science.gov (United States)

    Grasso, E J; Oliveira, R G; Maggio, B

    2016-02-15

    The molecular packing, thermodynamics and surface topography of binary Langmuir monolayers of Insulin and DPPC (dipalmitoylphosphatidylcholine) or POCP (1-palmitoyl-2-oleoylphosphatidylcholine) at the air/water interface on Zn(2+) containing solutions were studied. Miscibility and interactions were ascertained by the variation of surface pressure-mean molecular area isotherms, surface compressional modulus and surface (dipole) potential with the film composition. Brewster Angle Microscopy was used to visualize the surface topography of the monolayers. Below 20mN/m Insulin forms stable homogenous films with DPPC and POPC at all mole fractions studied (except for films with XINS=0.05 at 10mN/m where domain coexistence was observed). Above 20mN/m, a segregation process between mixed phases occurred in all monolayers without squeezing out of individual components. Under compression the films exhibit formation of a viscoelastic or kinetically trapped organization leading to considerable composition-dependent hysteresis under expansion that occurs with entropic-enthalpic compensation. The spontaneously unfavorable interactions of Insulin with DPPC are driven by favorable enthalpy that is overcome by unfavorable entropic ordering; in films with POPC both the enthalpic and entropic effects are unfavorable. The surface topography reveals domain coexistence at relatively high pressure showing a striped appearance. The interactions of Insulin with two major membrane phospholipids induces composition-dependent and long-range changes of the surface organization that ought to be considered in the context of the information-transducing capabilities of the hormone for cell functioning.

  15. Binding structure and kinetics of surfactin monolayer formed at the air/water interface to counterions: A molecular dynamics simulation study.

    Science.gov (United States)

    Gang, Hongze; Liu, Jinfeng; Mu, Bozhong

    2015-10-01

    The binding structure and kinetics of ionized surfactin monolayer formed at the air/water interface to five counterions, Li+, Na+, K+, Ca2+, and Ba2+ (molar ratios of surfactin to monovalent and divalent counterions are 1:2 and 1:1 respectively), have been studied using molecular dynamics simulation. The results show that surfactin exhibits higher binding affinity to divalent counterions, Ca2+, and Ba2+, and smaller monovalent counterion, Li+, than Na+ and K+. Both carboxyl groups in surfactin are accessible for counterions, but the carboxyl group in Glu1 is easier to access by counterions than Asp5. Salt bridges are widely built between carboxyl groups by counterions, and the probability of the formation of intermolecular salt bridge is markedly larger than that of intramolecular salt bridge. Divalent counterions perform well in forming salt bridges between carboxyl groups. The salt bridges mediated by Ca2+ are so rigid that the lifetimes are about 0.13 ns, and the break rates of these salt bridges are 1-2 orders of magnitude smaller than those mediated by K+ which is about 5 ps in duration. The positions of the hydration layer of carboxyl groups are independent of counterions, but the bound counterions induce the dehydration of carboxyl groups and disturb the hydrogen bonds built between carboxyl group and hydration water.

  16. Effect of temperature on the interfacial behavior of a polystyrene-b-poly(methyl methacrylate) diblock copolymer at the air/water interface.

    Science.gov (United States)

    Seo, Yongsok; Cho, Chung Yeon; Hwangbo, Minyoung; Choi, Hyoung Jin; Hong, Soon Man

    2008-03-18

    Monolayers of a polystyrene-poly(methyl methacrylate) (PS-PMMA) diblock copolymer at the air-water interface were studied by measuring the surface pressure-area isotherms at several temperatures. Langmuir film balance experiments and atomic force microscopy showed that the diblock copolymer molecules formed surface micelles. In the plot of the surface pressure versus surface area per repeating unit, the monolayer changed from the gas phase to the liquid expanded phase at lower surface pressure for systems at low temperature compared to those at high temperature. In addition, a plateau, corresponding to the transition from the liquid expanded to liquid condensed phase, appeared in that plot at lower surface pressure for systems with a higher subphase (water) temperature. Hysteresis was observed in the compression-expansion cycle process. Increasing the subphase temperature alleviated this hyteresis gap, especially at low surface pressures. The minimum in the plot of the surface pressure versus surface area per repeating unit in the expansion process (which arises from the transition) and the transition plateau appeared more vividly at higher water temperature. These dynamic experimental results show that PS-PMMA diblock copolymers, in which both blocks are insoluble in water, do not form complicated entanglements in two-dimensional space. Although higher water temperature provided more entropy to the chains, and thus more conformational freedom, it did not change the surface morphology of the condensed film because both blocks of PS-PMMA are insoluble in water.

  17. Chromatographie à contre-courant simulé : développements et perspectives From Batch Elution to Simulated Countercurrent Chromatography

    Directory of Open Access Journals (Sweden)

    Hotier G.

    2006-11-01

    where UOP still holds a quasi monopoly with the Molex process for n-isoparaffin separation and with the Parex process for paraxylene separation from C8 aromatic cuts. In the sugar industry competition is wide open. There are processes for glucose-fructose separation on the market (from Illinois Water Treatment, Mitsubishi Chemicals and UOP while a xylose-arabinose-glucose separation and a sucrose extraction from molasses are available from Finnsugar. Within this context Institut Français du Pétrole and Separex have developed the LICOSEP technology and propose its adaptation to different separations in the fine chemicals, pharmacy, perfumes and related industries. The principle of the simulated moving bed separation may be understood through the real countercurrent of a solvent and a solid selective adsorbing phase. In the mixture to be separated some of the components are relatively adsorbed while the other ones are not. The operations consist in adjusting the different flowrates so that the adsorbed compounds will be entrained with the solid while the nonadsorbed compounds will travel along with the liquid solvent. Actually the circulation of a solid phase is technically difficult. This operation is simulated by permutations of injected and withdrawn streams through multiple ports located all along the separation column. The practical construction of three pilot plants working according to the simulated moving bed technique is shown. Twenty-four columns filled with a fixed phase are mounted in series. A metering pump is fitted between the 24th and the first column in order to create a recirculation stream. Between each two columns it is possible to inject the feed or the solvent stream or to withdraw either the extract or the raffinate stream. These four streams flow continuously and each of them is directed by a twenty-four position valve to the right intercolumn assembly depending on the period of the cycle. Solvent injection, feed injection and extract withdrawal

  18. Predictions of bubbly flows in vertical pipes using two-fluid models in CFDS-FLOW3D code

    Energy Technology Data Exchange (ETDEWEB)

    Banas, A.O.; Carver, M.B. [Chalk River Laboratories (Canada); Unrau, D. [Univ. of Toronto (Canada)

    1995-09-01

    This paper reports the results of a preliminary study exploring the performance of two sets of two-fluid closure relationships applied to the simulation of turbulent air-water bubbly upflows through vertical pipes. Predictions obtained with the default CFDS-FLOW3D model for dispersed flows were compared with the predictions of a new model (based on the work of Lee), and with the experimental data of Liu. The new model, implemented in the CFDS-FLOW3D code, included additional source terms in the {open_quotes}standard{close_quotes} {kappa}-{epsilon} transport equations for the liquid phase, as well as modified model coefficients and wall functions. All simulations were carried out in a 2-D axisymmetric format, collapsing the general multifluid framework of CFDS-FLOW3D to the two-fluid (air-water) case. The newly implemented model consistently improved predictions of radial-velocity profiles of both phases, but failed to accurately reproduce the experimental phase-distribution data. This shortcoming was traced to the neglect of anisotropic effects in the modelling of liquid-phase turbulence. In this sense, the present investigation should be considered as the first step toward the ultimate goal of developing a theoretically sound and universal CFD-type two-fluid model for bubbly flows in channels.

  19. Interfacial area concentration in steady fully-developed bubbly flow

    Energy Technology Data Exchange (ETDEWEB)

    Hibiki, T. [Kyoto Univ., Research Reactor Institute (Japan); Ishii, M. [Purdue Univ., Lafayette, IN (United States). School of Nuclear Engineering

    2001-07-01

    A simple equation for the interfacial area concentration under steady fully-developed bubbly flow condition has been derived from the interfacial area transport equation. The derived theoretical equation has been modified to obtain experimentally supported predictive correlation. The obtained interfacial area correlation was validated by 204 data sets measured in air-water bubbly flows under various conditions. These data sets covered extensive flow and loop conditions such as channel geometry (circular or rectangular channel), flow direction (vertical or horizontal flow), superficial gas velocity (0,018 m/s - 4,87 m/s), superficial liquid velocity (0,262 m/s - 6,55 m/s) and interfacial area concentration (25,8 m{sup -1} - 1083 m{sup -1} ). An excellent agreement was obtained between the developed semi-theoretical correlation and data within an average relative deviation of 11,1 %. (author)

  20. Experimental researches on mass and heat transfer in new typical cross-flow rotating packed bed

    Institute of Scientific and Technical Information of China (English)

    CHEN Haihui; ZENG Yingying; GAO Wenshuai

    2006-01-01

    New typical cross-flow Rotating Packed Bed(RPB)called multi-pulverizing RPB was manufactured.There is enough void in multi-pulverizing RPB,where liquid easily flows and is repeatedly pulverized by light packing,which decreases the material consumed,lightens the weight,and compacts the structure.Mass and heat transfer property in the new type PRB were studied by two experimental models.In the mass transfer model,the axial fan pumping gas press is only 100 Pa,mass transfer coefficient and volumetric mass transfer coefficient are similar to countercurrent RPB,which are an order quantity lager than that in the conventional packed tower.In the heat transfer experiment,the axial fan pumping gas press is only 120 Pa;volumetric heatwhich especially suits the treatment of large gas flow and lower gas pressure drop.

  1. Water behavior in a U-shaped flow channel of PEM fuel cells. Paper no. IGEC-1-036

    Energy Technology Data Exchange (ETDEWEB)

    Quan, P.; Zhou, B.; Sobiesiak, A. [Univ. of Windsor, Dept. of Mechanical, Automotive and Materials Engineering, Windsor, Ontario (Canada)]. E-mail: bzhou@uwindsor.ca; Liu, Z.-S. [National Research Council Canada, Inst. for Fuel Cell innovation, Vancouver, British Columbia (Canada)

    2005-07-01

    The behavior of liquid water inside a U-shaped channel for a Proton Exchange Membrane (PEM) fuel cell was investigated through CFD modeling with the FLUENT software package. The Volume-Of-Fluid (VOF) model was adopted to track dynamic air-water interfaces. Three cases with varying initial water phase distributions corresponding to different fuel cell operating conditions were numerically simulated to obtain a better understanding of water behavior inside the serpentine channel. The results show that the bend area in the serpentine flow channel has significant effects on the flow field, which in turn affects the air-water flow and water liquid distribution inside the channel or along the interior channel surfaces, thus affecting fuel cell performance. (author)

  2. Evaluation of flow hydrodynamics in a pilot-scale dissolved air flotation tank: a comparison between CFD and experimental measurements.

    Science.gov (United States)

    Lakghomi, B; Lawryshyn, Y; Hofmann, R

    2015-01-01

    Computational fluid dynamics (CFD) models of dissolved air flotation (DAF) have shown formation of stratified flow (back and forth horizontal flow layers at the top of the separation zone) and its impact on improved DAF efficiency. However, there has been a lack of experimental validation of CFD predictions, especially in the presence of solid particles. In this work, for the first time, both two-phase (air-water) and three-phase (air-water-solid particles) CFD models were evaluated at pilot scale using measurements of residence time distribution, bubble layer position and bubble-particle contact efficiency. The pilot-scale results confirmed the accuracy of the CFD model for both two-phase and three-phase flows, but showed that the accuracy of the three-phase CFD model would partly depend on the estimation of bubble-particle attachment efficiency.

  3. Separation of five compounds from leaves of Andrographis paniculata (Burm. f.) Nees by off-line two-dimensional high-speed counter-current chromatography combined with gradient and recycling elution.

    Science.gov (United States)

    Zhang, Li; Liu, Qi; Yu, Jingang; Zeng, Hualiang; Jiang, Shujing; Chen, Xiaoqing

    2015-05-01

    An off-line two-dimensional high-speed counter-current chromatography method combined with gradient and recycling elution mode was established to isolate terpenoids and flavones from the leaves of Andrographis paniculata (Burm. f.) Nees. By using the solvent systems composed of n-hexane/ethyl acetate/methanol/water with different volume ratios, five compounds including roseooside, 5,4'-dihydroxyflavonoid-7-O-β-d-pyranglucuronatebutylester, 7,8-dimethoxy-2'-hydroxy-5-O-β-d-glucopyranosyloxyflavon, 14-deoxyandrographiside, and andrographolide were successfully isolated. Purities of these isolated compounds were all over 95% as determined by high-performance liquid chromatography. Their structures were identified by UV, mass spectrometry, and (1) H NMR spectroscopy. It has been demonstrated that the combination of off-line two-dimensional high-speed counter-current chromatography with different elution modes is an efficient technique to isolate compounds from complex natural product extracts.

  4. Application of an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum.

    Science.gov (United States)

    Chen, Tao; Liu, Yongling; Zou, Denglang; Chen, Chen; You, Jinmao; Zhou, Guoying; Sun, Jing; Li, Yulin

    2014-01-01

    This study presents an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum. A new solvent system composed of petroleum ether/ethyl acetate/water (4:2:1, v/v/v) was developed for the liquid-liquid extraction of the crude extract from R. tanguticum. As a result, emodin, aloe-emodin, physcion, and chrysophanol were greatly enriched in the organic layer. In addition, an efficient method was successfully established to separate and purify the above anthraquinones by high-speed counter-current chromatography and preparative HPLC. This study supplies a new alternative method for the rapid enrichment, separation, and purification of emodin, aloe-emodin, physcione, and chrysophanol.

  5. Regional assessment of anthropogenic impacts on air, water and soil, case: Huasteca Hidalguense, Mexico; Evaluacion regional del impacto antropogenico sobre aire, agua y suelo, caso: Huasteca Hidalguense, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gordillo Martinez, Alberto Jose; Cabrera Cruz, Rene Bernardo Elias; Hernandez Mariano, Marisol; Galindo, Erick; Otazo, Elena; Prieto, Francisco [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo, Pachuca, Hidalgo (Mexico)]. E-mail: gordillo@uaeh.edu.mx; rcabreracruz@yahoo.com.mx

    2010-08-15

    The state of Hidalgo, Mexico presents an important environmental problem that manifests itself in different ways. To identify the sources, types and the magnitude of pollutants, an inventory of sources of industrial and domestic pollution for air, water and soil in ten municipalities of the Huasteca Region of the state was carried out using the technique of Rapid Assessment of Sources of Environmental Pollution and the results are reported in this paper. A total of combined pollutants emitted was 116 978.95 tons/year. Gasoline vehicles contributed 11 039 tons/year of air pollutants and diesel vehicles 1521 tons/year. For water, industrial sources contributed 22 496 tons/year and domestic effluents 15 776 tons/year. Soil pollution was a result of industrial solid waste, 4025 tons/year, and municipal solid waste, 62 121 tons/year. By municipality, Huejutla de Reyes is the most polluted in air, water and soil, with 53 % of the regional total. These results were evaluated in relation to environmental quality of each medium based on the Mexican regulations; these levels are above permissible limits for water and soil. A database with relevant information was prepared as a support for efficient management of pollutant emissions, provide base mark data for complementary studies, and to promote the future conservation of environmental quality and the biological richness of the area. [Spanish] El estado de Hidalgo, Mexico presenta una importante problematica ambiental que se manifiesta de manera heterogenea a lo largo de su territorio. Existe la necesidad de conocer las fuentes, tipos de agentes contaminantes y su magnitud. En este trabajo se realizo un inventario de la contaminacion emitida por fuentes de origen industrial y domestico en aire, agua y suelo en diez municipios de la region de la Huasteca por medio de la tecnica de Evaluacion Rapida de Fuentes de Contaminacion Ambiental (ERFCA). El total de la contaminacion emitida fue de 116 978.95 ton/ano. Las emisiones al

  6. 高速逆流色谱法分离纯化黄酮类化合物的研究进展%Research progress on separation and purification of flavonoids by high-speed countercurrent chromatography

    Institute of Scientific and Technical Information of China (English)

    陈丛瑾; 杨国恩

    2011-01-01

    Objective To review research progress on the high-speed countercurrent chromatography separation and puritication of flavonoid compounds. Method Papers, monographs, etc. published in recent years, on the high-speed countercurrent chromatography separation and purification of flavonoids were reviewed and analyzed. Result and Conclusion High-speed countercurrent chromatography is a very effective separation and purification method of flavonoids.%目的 综述高速逆流色谱法分离纯化黄酮类化合物的研究进展.方法 查阅近年来公开发表的论文、专著等资料,对高速逆流色谱法分离纯化黄酮类化合物进行概述.结果 与结论高速逆流色谱法是一种非常有效的分离纯化黄酮类化合物的方法.

  7. Stability of stratified two-phase flows in inclined channels

    Science.gov (United States)

    Barmak, I.; Gelfgat, A. Yu.; Ullmann, A.; Brauner, N.

    2016-08-01

    Linear stability of the stratified gas-liquid and liquid-liquid plane-parallel flows in the inclined channels is studied with respect to all wavenumber perturbations. The main objective is to predict the parameter regions in which the stable stratified configuration in inclined channels exists. Up to three distinct base states with different holdups exist in the inclined flows, so that the stability analysis has to be carried out for each branch separately. Special attention is paid to the multiple solution regions to reveal the feasibility of the non-unique stable stratified configurations in inclined channels. The stability boundaries of each branch of the steady state solutions are presented on the flow pattern map and are accompanied by the critical wavenumbers and the spatial profiles of the most unstable perturbations. Instabilities of different nature are visualized by the streamlines of the neutrally stable perturbed flows, consisting of the critical perturbation superimposed on the base flow. The present analysis confirms the existence of two stable stratified flow configurations in a region of low flow rates in the countercurrent liquid-liquid flows. These configurations become unstable with respect to the shear mode of instability. It was revealed that in slightly upward inclined flows the lower and middle solutions for the holdup are stable in the part of the triple solution region, while the upper solution is always unstable. In the case of downward flows, in the triple solution region, none of the solutions are stable with respect to the short-wave perturbations. These flows are stable only in the single solution region at low flow rates of the heavy phase, and the long-wave perturbations are the most unstable ones.

  8. Bubble Formation Characteristics from a Sieve Tray with Liquid Cross—flow

    Institute of Scientific and Technical Information of China (English)

    XUSonglin; XUShimin

    2002-01-01

    An apparatus,desinged to simulate bubbling of a sieve tray operated in froth regime,was employed. Bubble contact angles in and above the incipient weeping regimer for an air-water-plexiglas system were investigated. The influence of both liquid cross-flow and gas up-flow upon bubble contact angles was examined. A model considering the influence of liquid cross-flow was developed to predict bubble size from a sieve hole in froth operation regime.The comparison shows that the bubble sizes predicted by the present model are consistent with our experimental values and the available published experimental data.

  9. Structure Parameter Optimization of Air-water Dual-source Compound Heat-exchanger%空气-水双热源复合换热器结构参数优化

    Institute of Scientific and Technical Information of China (English)

    张超; 董家昀; 赵晓丹; 周光辉

    2012-01-01

    空气-水双热源复合换热器是太阳能-空气双热源复合热泵系统的核心部件,空气-水双热源复台换热器的结构参数对空气-水双热源复合换热器的换热性能以及太阳能-空气双热源复合热泵的系统性能具有重要影响.建立了太阳能-空气双热源复合热泵系统的数学模型,利用数学模拟的方法研究了空气-水双热源复合换热器结构参数对热泵系统能效比的影响,并确定了模拟工况下换热器结构参数的优化方案.%The air-water dual-source compound heat-exchanger is the key component of the solar-air dual-source compound heat pump system. The heat-exchanging performance of the air-water dual-source compound heat-exchanger and the system performance of the solar-air dual-source compound heat pump system are largely depended on the structure parameter of the air-water dual-source compound heat-exchanger. The mathematic model of the solar-air dual-source compound heat pump system has been established. The mathematic simulation method has been used to study the effect of the structure parameters of air-water dual-source compound heat-exchanger on the energy-efficiency ratio of the solar-air dual-source compound heat pump system, and the optimization scheme of the structure parameters under the simulating condition have been determined.

  10. The AirWaterGas Teacher Professional Development Program: Lessons Learned by Pairing Scientists and Teachers to Develop Curriculum on Global Climate Change and Regional Unconventional Oil and Gas Development

    Science.gov (United States)

    Gardiner, L. S.; Hatheway, B.; Rogers, J. D.; Casey, J. G.; Lackey, G.; Birdsell, D.; Brown, K.; Polmear, M.; Capps, S.; Rosenblum, J.; Sitterley, K.; Hafich, K. A.; Hannigan, M.; Knight, D.

    2015-12-01

    The AirWaterGas Teacher Professional Development Program, run by the UCAR Center for Science Education, brought together scientists and secondary science teachers in a yearlong program culminating in the development of curriculum related to the impacts of unconventional oil and gas development. Graduate students and research scientists taught about their research area and its relationship to oil and gas throughout three online courses during the 2015-16 school year, during which teachers and scientists engaged in active online discussions. Topics covered included climate change, oil and gas infrastructure, air quality, water quality, public health, and practices and policies relating to oil and gas development. Building upon their initial online interactions and a face-to-face meeting in March, teachers were paired with appropriate AirWaterGas team members as science advisors during a month-long residency in Boulder, Colorado. During the residency, graduate student scientists provided resources and feedback as teachers developed curriculum projects in collaboration with each other and UCAR science educators. Additionally, teachers and AirWaterGas researchers shared experiences on an oil and gas well site tour, and a short course on drilling methods with a drilling rig simulator. Here, we share lessons learned from both sides of the aisle, including initial results from program assessment conducted with the participating teachers.

  11. Reynolds and froude number effect on the flow past an interface-piercing circular cylinder

    Directory of Open Access Journals (Sweden)

    Koo Bonguk

    2014-09-01

    Full Text Available The two-phase turbulent flow past an interface-piercing circular cylinder is studied using a high-fidelity orthogonal curvilinear grid solver with a Lagrangian dynamic subgrid-scale model for large-eddy simulation and a coupled level set and volume of fluid method for air-water interface tracking. The simulations cover the sub-critical and critical and post critical regimes of the Reynolds and sub and super-critical Froude numbers in order to investigate the effect of both dimensionless parameters on the flow. Significant changes in flow features near the air-water interface were observed as the Reynolds number was increased from the sub-critical to the critical regime. The interface makes the separation point near the interface much delayed for all Reynolds numbers. The separation region at intermediate depths is remarkably reduced for the critical Reynolds number regime. The deep flow resembles the single-phase turbulent flow past a circular cylinder, but includes the effect of the free-surface and the limited span length for sub-critical Reynolds numbers. At different Froude numbers, the air-water interface exhibits significantly changed structures, including breaking bow waves with splashes and bubbles at high Froude numbers. Instantaneous and mean flow features such as interface structures, vortex shedding, Reynolds stresses, and vorticity transport are also analyzed. The results are compared with reference experimental data available in the literature. The deep flow is also compared with the single-phase turbulent flow past a circular cylinder in the similar ranges of Reynolds numbers. Discussion is provided concerning the limitations of the current simulations and available experimental data along with future research

  12. Transport-driven scrape-off layer flows and the x-point dependence of the L-H power threshold in Alcator C-Moda)

    Science.gov (United States)

    LaBombard, B.; Rice, J. E.; Hubbard, A. E.; Hughes, J. W.; Greenwald, M.; Granetz, R. S.; Irby, J. H.; Lin, Y.; Lipschultz, B.; Marmar, E. S.; Marr, K.; Mossessian, D.; Parker, R.; Rowan, W.; Smick, N.; Snipes, J. A.; Terry, J. L.; Wolfe, S. M.; Wukitch, S. J.

    2005-05-01

    Factor of ˜2 higher power thresholds for low- to high-confinement mode transitions (L-H) with unfavorable x-point topologies in Alcator C-Mod [Phys. Plasmas 1, 1511 (1994)] are linked to flow boundary conditions imposed by the scrape-off layer (SOL). Ballooning-like transport drives flow along magnetic field lines from low- to high-field regions with toroidal direction dependent on upper/lower x-point balance; the toroidal rotation of the confined plasma responds, exhibiting a strong counter-current rotation when B ×∇B points away from the x point. Increased auxiliary heating power (rf, no momentum input) leads to an L-H transition at approximately twice the edge electron pressure gradient when B ×∇B points away. As gradients rise prior to the transition, toroidal rotation ramps toward the co-current direction; the H mode is seen when the counter-current rotation imposed by the SOL flow becomes compensated. Remarkably, L-H thresholds in lower-limited discharges are identical to lower x-point discharges; SOL flows are also found similar, suggesting a connection.

  13. Heat production in depth up to 2500m via in situ combustion of methane using a counter-current heat-exchange reactor

    Science.gov (United States)

    Schicks, Judith Maria; Spangenberg, Erik; Giese, Ronny; Heeschen, Katja; Priegnitz, Mike; Luzi-Helbing, Manja; Thaler, Jan; Abendroth, Sven; Klump, Jens

    2014-05-01

    In situ combustion is a well-known method used for exploitation of unconventional oil deposits such as heavy oil/bitumen reservoirs where the required heat is produced directly within the oil reservoir by combustion of a small percentage of the oil. A new application of in situ combustion for the production of methane from hydrate-bearing sediments was tested at pilot plant scale within the first phase of the German national gas hydrate project SUGAR. The applied method of in situ combustion was a flameless, catalytic oxidation of CH4 in a counter-current heat-exchange reactor with no direct contact between the catalytic reaction zone and the reservoir. The catalyst permitted a flameless combustion of CH4 with air to CO2 and H2O below the auto-ignition temperature of CH4 in air (868 K) and outside the flammability limits. This led to a double secured application of the reactor. The relatively low reaction temperature allowed the use of cost-effective standard materials for the reactor and prevented NOx formation. Preliminary results were promising and showed that only 15% of the produced CH4 was needed to be catalytically burned to provide enough heat to dissociate the hydrates in the environment and release CH4. The location of the heat source right within the hydrate-bearing sediment is a major advantage for the gas production from natural gas hydrates as the heat is generated where it is needed without loss of energy due to transportation. As part of the second period of the SUGAR project the reactor prototype of the first project phase was developed further to a borehole tool. The dimensions of this counter-current heat-exchange reactor are about 540 cm in length and 9 cm in diameter. It is designed for applications up to depths of 2500 m. A functionality test and a pressure test of the reactor were successfully carried out in October 2013 at the continental deep drilling site (KTB) in Windischeschenbach, Germany, in 600 m depth and 2000 m depth, respectively

  14. VERTICAL FLOW OF GAS-LIQUID-SOLID PARTICLES SYSTEM

    OpenAIRE

    幡手, 泰雄; 野村, 博; 碇, 醇; ハタテ, ヤスオ; ノムラ, ヒロシ; イカリ, アツシ; HATATE, Yasuo; Nomura, Hiroshi; IKARI, Atsushi

    1983-01-01

    It is significant to know the hydrodynamic characteristics of the system in the design and scale-up of reactors containing gas-liquid-solid particles system. As a fundamental study of such a three-phase flow, the gas holdup and the pressure drop were measured in the vertical tubes, through which various mixtures of air, water, and fine glass-sphere, particles were passed. Three kinds of glass particles were used the average sizes of which were 30, 60 and 90 μm. Two kinds of tubes, 15 an...

  15. IDENTIFICATION OF GAS-LIQUID FLOW REGIMES IN A HORIZONTAL FLOW USING NEURAL NETWORK

    Institute of Scientific and Technical Information of China (English)

    JIA Zhi-hai; NIU Gang; WANG Jing

    2005-01-01

    The knowledge of flow regimes is very important in the study of a two-phase flow system. A new flow regime identification method based on a Probability Density Function (PDF) and a neural network is proposed in this paper. The instantaneous differential pressure signals of a horizontal flow were acquired with a differential pressure sensor. The characters of differential pressure signals for different flow regimes are analyzed with the PDF. Then, four characteristic parameters of the PDF curves are defined, the peak number (K1), the maximum peak value (K2), the peak position (K3) and the PDF variance (K4). The characteristic vectors which consist of the four characteristic parameters as the input vectors train the neural network to classify the flow regimes. Experimental results show that this novel method for identifying air-water two-phase flow regimes has the advantages with a high accuracy and a fast response. The results clearly demonstrate that this new method could provide an accurate identification of flow regimes.

  16. INFLUENCE OF SURFACTANT ON TWO-PHASE FLOW REGIME AND PRESSURE DROP IN UPWARD INCLINED PIPES

    Institute of Scientific and Technical Information of China (English)

    XIA Guo-dong; CHAI Lei

    2012-01-01

    The influence of a surfactant on the two-phase flow regime and the pressure drop in upward inclined pipes is investigated for various gas/liquid flow rates.The air/water and air/100 ppm sodium dodecyl sulphate aqueous solution are used as the working fluids.The influence of the surfactant on the two-phase flow regime in upward inclined pipes is investigated using the electrical tomographic technique.For 0°,2.5° and 5° pipe inclinations,the surfactant has obvious effect on the transition from the stratified wavy flow to the annular flow,and the range of the stratified smooth flow regime is also extended to higher gas velocities.For 10°pipe inclination,no stratified flow regime is observed in the air/water flow.In the air/surfactant solution system,however,the stratified flow regime can be found in the range of USG =10m/s-28m/s and USL =0.07 m/s-0.2 m/s.For all inclination angles,the changes of the pressure gradient characteristics are accompanied with the flow pattern transitions.Adding surfactant in a two-phase flow would reduce the pressure gradient significantly in the slug flow and annular flow regimes.In the annular flow regime,the pressure gradient gradually becomes free of the influence of the upward inclined angle,and is only dependent on the property of the two-phase flow.

  17. "Reagentless" flow injection determination of ammonia and urea using membrane separation and solid phase basification

    Science.gov (United States)

    Akse, J. R.; Thompson, J. O.; Sauer, R. L.; Atwater, J. E.

    1998-01-01

    Flow injection analysis instrumentation and methodology for the determination of ammonia and ammonium ions in an aqueous solution are described. Using in-line solid phase basification beds containing crystalline media. the speciation of ammoniacal nitrogen is shifted toward the un-ionized form. which diffuses in the gas phase across a hydrophobic microporous hollow fiber membrane into a pure-water-containing analytical stream. The two streams flow in a countercurrent configuration on opposite sides of the membrane. The neutral pH of the analytical stream promotes the formation of ammonium cations, which are detected using specific conductance. The methodology provides a lower limit of detection of 10 microgram/L and a dynamic concentration range spanning three orders of magnitude using a 315-microliters sample injection volume. Using immobilized urease to enzymatically promote the hydrolysis of urea to produce ammonia and carbon dioxide, the technique has been extended to the determination of urea.

  18. Droplet entrainment rate in gas-liquid annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, P. [Energy Research Inc., Rockville, Maryland (United States); Liu, Y.; Ishii, M. [Purdue Univ., West Lafayette, Indiana (United States); Mori, M. [Tokyo Electric Power Co., Inc., Yokohama (Japan); Chen, S. [Purdue Univ., West Lafayette, Indiana (United States)

    2011-07-01

    Droplet entrainment and deposition are the two most important physical phenomena in the gas-liquid annular two-phase flow. Modeling of these phenomena is essential for the estimation of dryout margins in the Light Water Reactors (LWRs) and the boilers. In this study, gas-liquid annular two-phase flow experiments are performed in a vertical round tube test section under adiabatic conditions. Air-water and organic fluid Freon-113 are used as the test fluids. The experiments covered a wide range of pressure and flow conditions. Liquid film extraction technique was used for the measurement of droplet entrainment and deposition rates. Additionally, the thickness of liquid film was measured in the air-water experiments using the ring type conductance probes. In this paper, the experimental data on entrainment rate is used to analyze the currently available correlations in the literature. The analysis showed that the existing correlations failed to predict the data at high gas velocity conditions. At high gas velocity, the experimental entrainment rate approaches a maximum limiting value; however, the correlations predicted continuously increasing entrainment rate as the gas velocity increases. (author)

  19. Direct velocity measurement and enhanced mixing in laminar flows over ultrahydrophobic surfaces

    Science.gov (United States)

    Ou, Jia

    2005-11-01

    A series of experiment are presented studying the kinematics of water flowing over drag-reducing ultrahydrophobic surfaces. The surfaces are fabricated from silicon wafers using photolithography and are designed to incorporate patterns of microridges with precise spacing and alignment. These surfaces are reacted with an organosilane to achieve high hydrophobicity. Microridges with different widths, spacing and alignments are tested in a microchannel flow cell with rectangular cross-section. The velocity profile across the microchannel is measured with micro particle image velocimetry (μ-PIV) capable of resolving the flow down to length scales well below the size of the surface features. A maximum slip velocity of >60% of the average velocity in the flow is observed at the center of the air-water interface supported between these hydrophobic microridges, and the no-slip boundary condition is found at the hydrophobic microridges. The μ-PIV measurements demonstrate that slip along the shear-free air-water interface supported between the hydrophobic micron-sized ridges is the primary mechanism responsible for the drag reduction. The experiment velocity and pressure drop measurement are compared with the prediction of numerical simulation and an analytical model. By aligning the hydrophobic microridges at an acute angle to the flow direction a secondary flow is produced which can significantly enhance mixing in this laminar flow.

  20. 空气-水/吸湿溶液热湿传递特性分析(Ⅰ)可及处理区域%An analysis for heat and moisture transfer effect in air-water or-hydroscopic solution ( Ⅰ ) Reachable handling region

    Institute of Scientific and Technical Information of China (English)

    张涛; 刘晓华; 江亿

    2011-01-01

    A model is established to analyze the heat and moisture transfer process in air-water or-hydroscopic solution system, two independent driving forces each other: enthalpy difference and relative humidity difference can be obtained. A triangle region, consisting of iso-enthalpy line from air inlet, saturation line of moisture air (iso-concentration line of solution) and connecting line of air and water or solution at inlet status, is determined in enthalpy-psychrometric chart based on relationship between the two driving forces. The region is a reachable handling region for heat and moisture transfer process in air-water or-hydroscopic solution system, because the variation of air outlet status is limited in the region whatever change of mass and heat transfer coefficients or flow pattern and rate. Experimental results of dehumidification and regeneration in literatures are analyzed with the help of reachable handling region.%利用模型研究空气与水或吸湿溶液热湿传递过程的特性,得到两个相互独立的驱动力——焓差驱动力和相对湿度差驱动力.根据两驱动力的关系在焓湿图上确定了一个由空气进口等焓线、湿空气饱和线(或溶液等浓度线)、空气与水或溶液进口状态连线围成的三角形区域,不论流型、传热传质系数或流量如何变化,空气出口状态只能在该区域内变化,即为空气与水或吸湿溶液热湿传递过程的可及处理区域.应用可及处理区域分析了文献中除湿实验、再生实验的热湿处理结果,明确了实验装置所处的性能水平.

  1. Offline coupling of high-speed counter-current chromatography and gas chromatography/mass spectrometry generates a two-dimensional plot of toxaphene components.

    Science.gov (United States)

    Kapp, Thomas; Vetter, Walter

    2009-11-20

    High-speed counter-current chromatography (HSCCC), a separation technique based solely on the partitioning of solutes between two immiscible liquid phases, was applied for the fractionation of technical toxaphene, an organochlorine pesticide which consists of a complex mixture of structurally closely related compounds. A solvent system (n-hexane/methanol/water 34:24:1, v/v/v) was developed which allowed to separate compounds of technical toxaphene (CTTs) with excellent retention of the stationary phase (S(f) = 88%). Subsequent analysis of all HSCCC fractions by gas chromatography coupled to electron-capture negative ion mass spectrometry (GC/ECNI-MS) provided a wealth of information regarding separation characteristics of HSCCC and the composition of technical toxaphene. The visualization of the large amount of data obtained from the offline two-dimensional HSCCC-GC/ECNI-MS experiment was facilitated by the creation of a two-dimensional (2D) contour plot. The contour plot not only provided an excellent overview of the HSCCC separation progress, it also illustrated the differences in selectivity between HSCCC and GC. The results of this proof-of-concept study showed that the 2D chromatographic approach involving HSCCC facilitated the separation of CTTs that coelute in unidimensional GC. Furthermore, the creation of 2D contour plots may provide a useful means of enhancing data visualization for other offline two-dimensional separations.

  2. A new tropane alkaloid from the leaves of Erythroxylum subsessile isolated by pH-zone-refining counter-current chromatography.

    Science.gov (United States)

    Cruz, Rodrigo Alves Soares; Almeida, Henrique; Fernandes, Caio Pinho; Joseph-Nathan, Pedro; Rocha, Leandro; Leitão, Gilda Guimarães

    2016-04-01

    Tropane alkaloids are bioactive metabolites with great importance in the pharmaceutical industry and the most important class of natural products found in the Erythroxylum genus. However, these compounds are usually separated by traditional chromatographic techniques, in which the sample is progressively purified in multiple chromatographic steps, resulting in a time- and solvent-consuming procedure. In this work we present the isolation of a novel alkaloid, 6β,7β-dibenzoyloxytropan-3α-ol, together with the two known 3α-benzoyloxynortropan-6β-ol and 3α,6β-dibenzoyloxytropane alkaloids, directly from the crude alkaloid fraction from the leaves of Erythroxylum subsessile, by using a single run pH-zone-refining counter-current chromatography method. The ethyl acetate/water (1:1, v/v) biphasic solvent system with triethylamine and HCl as retention and eluter agents, respectively, was used to isolate tropane alkaloids for the first time. The structures of the isolated alkaloids were elucidated by spectroscopic methods.

  3. Separation of polyphenols from leaves of Malus hupehensis (Pamp.) Rehder by off-line two-dimensional High Speed Counter-Current Chromatography combined with recycling elution mode.

    Science.gov (United States)

    Liu, Qi; Zeng, Hualiang; Jiang, Shujing; Zhang, Li; Yang, Fuzhu; Chen, Xiaoqing; Yang, Hua

    2015-11-01

    In this study, off-line two-dimensional High Speed Counter-Current Chromatography (2D HSCCC) strategy combined with recycling elution mode was developed to isolate compounds from the ethyl acetate extract of a common green tea--leaves of Malus hupehensis (Pamp.) Rehder. In the orthogonal separation system, a conventional HSCCC was employed for the first dimension and two recycling HSCCCs were used for the second in parallel. Using a solvent system consisting of n-hexane-ethyl acetate-methanol-water (1:4:0.6:4.4, v/v) in the first and second dimension, four compounds including 3-hydroxy-phlorizin (1), phloretin (2), avicularin (3) and kaempferol 3-O-β-D-glucoside (4) were obtained. The purities of these four compounds were all over 95.0% as determined by HPLC. And their structures were all identified through UV, MS and (1)H NMR. It has been demonstrated that the combination of off-line 2D HSCCC with recycling elution mode is an efficient technique to isolate compounds with similar polarities in natural products.

  4. Isolation of C-glycosylflavonoids with α-glucosidase inhibitory activity from Passiflora bogotensis Benth by gradient high-speed counter-current chromatography.

    Science.gov (United States)

    Costa, Geison Modesti; Cárdenas, Paola Andrea; Gazola, Andressa Córneo; Aragón, Diana Marcela; Castellanos, Leonardo; Reginatto, Flávio Henrique; Ramos, Freddy Alejandro; Schenkel, Eloir Paulo

    2015-05-15

    In this study, we applied a gradient High-Speed Counter-Current Chromatography (HSCCC) method that allowed, by direct injection of an aqueous crude extract of the leaves of Passiflora bogotensis, the successful isolation of six flavonoids in a single run, with purity of each compound higher than 81%. This separation enabled the isolation of two new flavonoid glycosides, apigenin-6-C-α-l-rhamnopyranosyl-(1→2)-(6″-O-acetyl)-β-d-glucopyranoside (2) and luteolin-6-C-α-l-rhamnopyranosyl-(1→2)-(6″-O-acetyl)-β-d-glucopyranoside (4), and four known ones, isovitexin (1), isoorientin (3), isovitexin-2″-O-rhamnoside (5) and isoorientin-2″-O-rhamnoside (6). The structures of the isolated compounds were identified by HPLC-DAD, LC-MS, (1)H and (13)C NMR and comparison with literature data. The inhibitory activities of all of these compounds were evaluated in vitro on α-glucosidase from S. cerevisiae, and the IC50 was determinate. This is the first study concerning the chemical composition and biological activity of Passiflora bogotensis.

  5. Rapid preparative separation of six bioactive compounds from Gentiana crassicaulis Duthie ex Burk. using microwave-assisted extraction coupled with high-speed counter-current chromatography.

    Science.gov (United States)

    Liang, Jinru; Ito, Yoichiro; Zhang, Xinxin; He, Jiao; Sun, Wenji

    2013-12-01

    A rapid method combining microwave-assisted extraction (MAE) and high-speed counter-current chromatography (HSCCC) was applied for preparative separation of six bioactive compounds including loganic acid (I), isoorientin-4'-O-glucoside (II), 6'-O-β-d-glucopyranosyl gentiopicroside (III), swertiamarin (IV), gentiopicroside (V), sweroside (VI) from traditional Tibetan medicine Gentiana crassicaulis Duthie ex Burk. MAE parameters were predicted by central composite design response surface methodology. That is, 5.0 g dried roots of G. crassicaulis were extracted with 50 mL 57.5% aqueous ethanol under 630 W for 3.39 min. The extract (gentian total glycosides) was separated by HSCCC with n-butanol/ethyl acetate/methanol/1% acetic acid water (7.5:0.5:0.5:3.5, v/v/v/v) using upper phase mobile in tail-to-head elution mode. 16.3, 8.8, 12., 25.1, 40.7, and 21.8 mg of compounds I-VI were obtained with high purities in one run from 500 mg of original sample. The purities and identities of separated components were confirmed using HPLC with photo diode array detection and quadrupole TOF-MS and NMR spectroscopy. The study reveals that response surface methodology is convenient and highly predictive for optimizing extraction process, MAE coupled with HSCCC could be an expeditious method for extraction and separation of phytochemicals from ethnomedicine.

  6. Continuous countercurrent chromatographic separator for the purification of sugars from biomass hydrolyzate. Final project report, July 1, 1996--September 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Wooley, R J

    1997-12-01

    Production of pure sugars is required to enable production of fuels and chemicals from biomass feedstocks. Hydrolysis of cellulose and hemicellulose (principal constituents of biomass) produces sugars that can be utilized in various fermentation process to produce valuable chemicals. Unfortunately, the hydrolysis process also liberates chemicals from the biomass that can be toxic to the fermenting organisms. The two primary toxic components of biomass hydrolyzate are sulfuric acid (catalyst used in the hydrolysis) and acetic acid (a component of the feed biomass). In the standard batch chromatographic separation of these three components, sugar elutes in the middle. Batch chromatographic separations are not practical on a commercial scale, because of excess dilution and high capital costs. Because sugar is the {open_quotes}center product,{close_quotes} a continuous separation would require two costly binary separators. However, a single, slightly larger separator, configured to produce three products, would be more economical. This FIRST project develops a cost-effective method for purifying biomass hydrolyzate into fermentable sugars using a single continuous countercurrent separator to separate this ternary mixture.

  7. Rhinovirus uses a phosphatidylinositol 4-phosphate/cholesterol counter-current for the formation of replication compartments at the ER-Golgi interface.

    Science.gov (United States)

    Roulin, Pascal S; Lötzerich, Mark; Torta, Federico; Tanner, Lukas B; van Kuppeveld, Frank J M; Wenk, Markus R; Greber, Urs F

    2014-11-12

    Similar to other positive-strand RNA viruses, rhinovirus, the causative agent of the common cold, replicates on a web of cytoplasmic membranes, orchestrated by host proteins and lipids. The host pathways that facilitate the formation and function of the replication membranes and complexes are poorly understood. We show that rhinovirus replication depends on host factors driving phosphatidylinositol 4-phosphate (PI4P)-cholesterol counter-currents at viral replication membranes. Depending on the virus type, replication required phosphatidylinositol 4-kinase class 3beta (PI4K3b), cholesteryl-esterase hormone-sensitive lipase (HSL) or oxysterol-binding protein (OSBP)-like 1, 2, 5, 9, or 11 associated with lipid droplets, endosomes, or Golgi. Replication invariably required OSBP1, which shuttles cholesterol and PI4P between ER and Golgi at membrane contact sites. Infection also required ER-associated PI4P phosphatase Sac1 and phosphatidylinositol (PI) transfer protein beta (PITPb) shunting PI between ER-Golgi. These data support a PI4P-cholesterol counter-flux model for rhinovirus replication.

  8. Bioassay-guided preparative separation of angiotensin-converting enzyme inhibitory C-flavone glycosides from Desmodium styracifolium by recycling complexation high-speed counter-current chromatography.

    Science.gov (United States)

    Zhang, Ying-Qi; Luo, Jian-Guang; Han, Chao; Xu, Jin-Fang; Kong, Ling-Yi

    2015-01-01

    A new strategy of the convergence of high-speed counter-current chromatography (HSCCC) and bioactive assay technique was developed for rapidly screening and separating the angiotensin-converting enzyme (ACE) inhibitors from the aerial parts of Desmodium styracifolium. Bioactivity-guided fractionation of the crude extract was first established to target the bioactive fractions based on HSCCC coupled with in vitro ACE inhibitory assay. Subsequently, the bioactive fractions were further separated by the recycling complexation HSCCC respectively, using 0.10 mol/L copper sulfate in the lower phase of two-phase solvent system composed of n-butanol/water (1:1, v/v). Five C-glycosylflavones, vicenin 2 (1), carlinoside (2), vicenin 1 (3), schaftoside (4) and vicenin 3 (5), were successfully obtained. Their chemical structures were identified using ESI-MS and NMR. All the isolates showed in vitro ACE inhibitory activity with the IC50 values between 33.62 and 58.37 μM. The results demonstrated that the established method was proposed as an excellent strategy to systematically screen and purify active compounds from traditional Chinese medicines.

  9. Preparative isolation and purification of lignans from Justicia procumbens using high-speed counter-current chromatography in stepwise elution mode.

    Science.gov (United States)

    Zhou, Peijuan; Luo, Qijun; Ding, Lijian; Fang, Fang; Yuan, Ye; Chen, Juanjuan; Zhang, Jinrong; Jin, Haixiao; He, Shan

    2015-04-20

    Lignans, which are recognized as main constituents in Justicia procumbens, have attracted considerable attention due to their pharmacological activities, including antitumor, anti-hepatitic, cytotoxic, anti-microbial, and anti-virus properties. Preparative high-speed counter-current chromatography (HSCCC) was successfully applied to the isolation and purification of four lignans (justicidin B (1), justicidin A (2), 6'-hydroxyjusticidin C (3) and lignan J1 (4)) from J. procumbens using stepwise elution with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at (1.3:1:1.3:1, v/v) and (2.5:1:2.5:1, v/v). The preparative HSCCC separation was performed on 300 mg of crude sample yielding compounds 1 (19.7 mg), 2 (9.86 mg), 3 (11.26 mg), and 4 (2.54 mg) in a one-step separation, with purities over 95% as determined by HPLC. The structures of these compounds were identified by MS, 1H-NMR and 13C-NMR. This is the first report on the application of HSCCC to the efficient separation of lignans from J. procumbens.

  10. Solvent systems with n-hexane and/or cyclohexane in countercurrent chromatography--Physico-chemical parameters and their impact on the separation of alkyl hydroxybenzoates.

    Science.gov (United States)

    Englert, Michael; Vetter, Walter

    2014-05-16

    Countercurrent chromatography (CCC) is an efficient preparative separation technique based on the liquid-liquid distribution of compounds between two phases of a biphasic liquid system. The crucial parameter for the successful application is the selection of the solvent system. Especially for nonpolar analytes the selection options are limited. On the search for a suitable solvent system for the separation of an alkyl hydroxybenzoate homologous series, we noted that the substitution of cyclohexane with n-hexane was accompanied with unexpected differences in partitioning coefficients of the individual analytes. In this study, we investigated the influence of the subsequent substitution of n-hexane with cyclohexane in the n-hexane/cyclohexane/tert-butylmethylether/methanol/water solvent system family. Exact phase compositions and polarity, viscosity and density differences were determined to characterize the different mixtures containing n-hexane and/or cyclohexane. Findings were confirmed by performing CCC separations with different mixtures, which led to baseline resolution for positional isomers when increasing the amount of cyclohexane while the resolution between two pairs of structural isomers decreased. With the new methodology described, structurally similar compounds could be resolved by choosing a certain ratio of n-hexane to cyclohexane.

  11. Application of high-speed counter-current chromatography for isolation of triterpenes from Schisandra Chinensis (Turcz.) Baill and induction apoptosis mechanism of HSC-T6.

    Science.gov (United States)

    Li, Bin; Meng, Xianjun; Zhu, Lijie; Jiao, Xinyao; Zhang, Jiachen

    2014-01-01

    Triterpenes have shown many beneficial activities in researches, but their separation and preparation usually require multiple methods. Following an initial cleaning-up step on the AB-8 macroporous resin, a preparative high-speed counter-current chromatography (HSCCC) with a two-phase solvent system comprising chloroform-n-butyl alcohol-methanol-water (10:1:7:4, v/v/v/v) was used to isolate and separate triterpenes from caculis of Schisandra Chinensis (Turcz.) baill. A total of 89 mg corosolic acid with purities of 98.5% were obtained from 400 mg crude extract in one-step elution and less than 4 h, and the structure identification was performed by UV, IR, MS, 1H NMR and 13C NMR. The inhibition on liver fibrosis activities of the triterpenes against HSC-T6 in vitro were studied by cell culture methods. The results showed that the corosolic acid have better inhibitory effects on HSC-T6 cells with the IC50 value of 5~25 μg/mL and the study also indicated that corosolic acid might be a potential Chinese medical component to inhibit liver fibrosis.

  12. Separation of isorhamnetin 3-sulphate and astragalin from Flaveria bidentis (L.) Kuntze using macroporous resin and followed by high-speed countercurrent chromatography.

    Science.gov (United States)

    Shaheen, Nusrat; Yin, Li; Gu, Yanxiang; Rwigimba, Eric; Xie, Qianqian; Wei, Yun

    2015-06-01

    D4020 resin offered the best dynamic adsorption and desorption capacity for total flavonoids based on the research results from ten kinds of macroporous resin. A column packed with D4020 resin was used to optimize the separation of total flavonoids from Flaveria bidentis (L.) Kuntze extracts. The content of flavonoids in the product was increased from 4.3 to 30.1% with a recovery yield of 90%. After the treatment with gradient elution on D4020 resin, the contents of isorhamnetin 3-sulfate and astragalin were increased from 0.49 to 8.70% with a recovery yield of 74.1% and 1.16 to 30.8%, with a recovery yield of 92.2%, respectively. Further purification was carried out by one-run high-speed countercurrent chromatography yielding 4.5 mg of isorhamnetin 3-sulfate at a high purity of 96.48% and yielding 24.4 mg of astragalin at a high purity of over 98.46%.

  13. One-step separation of nine structural analogues from Poria cocos (Schw.) Wolf. via tandem high-speed counter-current chromatography.

    Science.gov (United States)

    Zeng, Hualiang; Liu, Qi; Yu, Jingang; Jiang, Xinyu; Wu, Zhiliang; Wang, Meiling; Chen, Miao; Chen, Xiaoqing

    2015-11-01

    A novel one-step separation strategy-tandem high-speed counter-current chromatography (HSCCC) was developed with a six-port valve serving as the switch interface. Nine structural analogues including three isomers were successfully isolated from Poria cocos (Schw.) Wolf. by one step. Compared with conventional HSCCC, peak resolution of target compounds was effectively improved in tandem one. Purities of isolated compounds were all over 90% as determined by HPLC. Their structures were then identified via UV, MS and (1)H NMR, and eventually assigned as poricoic acid B (1), poricoic acid A (2), 3β,16α-dihydroxylanosta-7, 9(11), 24-trien-21-oic acid (3), dehydrotumulosic acid (4), polyporenic acid C (5), 3-epi-dehydrotumulosic acid (6), 3-o-acetyl-16α-hydroxydehydrotrametenolic acid (7), dehydropachymic acid (8) and dehydrotrametenolic acid (9) respectively. The results indicated that tandem HSCCC can effectively improve peak resolution of target compounds, and can be a good candidate for HSCCC separation of structural analogues.

  14. Preparative isolation and purification of senkyunolide-I, senkyunolide-H and ferulic acid from Rhizoma Chuanxiong using counter-current chromatography.

    Science.gov (United States)

    Wei, Yun; Hu, Jia; Li, Hao; Liu, Jiangang

    2011-12-01

    Three active compounds, senkyunolide-I, senkyunolide-H and ferulic acid (FA), were successfully isolated and purified from the extracts of Rhizoma Chuanxiong by counter-current chromatography (CCC). Based on the principle of the partition coefficient values (k) for target compounds and the separation factor (α) between target compounds, the two-phase solvent system that contains n-hexane-ethyl acetate-methanol-water at an optimized volume ratio of 3:7:4:6 v/v was selected for the CCC separation, and the lower phase was employed as the mobile phase in the head-to-tail elution mode. In a single run, 400 mg of the crude extract yielded pure senkyunolide-I (6.4 mg), senkyunolide-H (1.7 mg) and FA (4.4 mg) with the purities of 98, 93 and 99%, respectively. The CCC fractions were analyzed by high-performance liquid chromatography, and the structures of the three active compounds were identified by MS and (1)H NMR.

  15. Separation and identification of polyphenols in apple pomace by high-speed counter-current chromatography and high-performance liquid chromatography coupled with mass spectrometry.

    Science.gov (United States)

    Cao, Xueli; Wang, Cong; Pei, Hairun; Sun, Baoguo

    2009-05-01

    Apple pomace, a by-product in the processing of apple juice, was investigated as a potential source of polyphenols. Two methods of separation and purification of polyphenols from apple pomace extract were established by combination of gel chromatography with high-speed counter-current chromatography (HSCCC) and solvent extraction with HSCCC, respectively. The optimal separation was performed on a Sephadex LH-20 column using gradient aqueous ethanol as eluting solvent from 0% to 100% in increments of 10%. HPLC analysis indicated that main polyphenols existed in fractions eluted between 40% and 50% aqueous ethanol. The fractions of interest from column were separated by HSCCC with the solvent system hexane-ethyl acetate-1% aqueous acetic acid (0.5:9.5:10, v/v/v). Ethyl acetate fractionation of the apple pomace extract followed by direct HSCCC separation by the same solvent system in the volume ratio of 1:9:10 also produced a good separation of the main polyphenols of interest. Six high-purity polyphenols were achieved tentatively and identified by HPLC/MS: chlorogenic acid (1, m/z 354), quercetin-3-glucoside/quercetin-3-glacaside (2, m/z 464), quercetin-3-xyloside (3, m/z 434), phloridzin (4, m/z 436), quercetin-3-arabinoside (5, m/z 434), and quercetin-3-rhamnoside (6, m/z 448). These results provided a preliminary foundation for further development and exploration of apple pomace.

  16. Correlation and prediction of partition coefficient using nonrandom two-liquid segment activity coefficient model for solvent system selection in counter-current chromatography separation.

    Science.gov (United States)

    Ren, Da-Bing; Yang, Zhao-Hui; Liang, Yi-Zeng; Ding, Qiong; Chen, Chen; Ouyang, Mei-Lan

    2013-08-02

    Selection of a suitable solvent system is the first and foremost step for a successful counter-current chromatography (CCC) separation. In this paper, a thermodynamic model, nonrandom two-liquid segment activity coefficient model (NRTL-SAC) which uses four types of conceptual segments to describe the effective surface interactions for each solvent and solute molecule, was employed to correlate and predict the partition coefficients (K) of a given compound in a specific solvent system. Then a suitable solvent system was selected according to the predicted partition coefficients. Three solvent system families, heptane/methanol/water, heptane/ethyl acetate/methanol/water (Arizona) and hexane/ethyl acetate/methanol/water, and several solutes were selected to investigate the effectiveness of the NRTL-SAC model for predicting the partition coefficients. Comparison between experimental results and predicted results showed that the NRTL-SAC model is of potential for estimating the K value of a given compound. Also a practical separation case on magnolol and honokiol suggests the NRTL-SAC model is effective, reliable and practical for the purpose of predicting partition coefficients and selecting a suitable solvent system for CCC separation.

  17. Isolation of aspalathin and nothofagin from rooibos (Aspalathus linearis) using high-performance countercurrent chromatography: sample loading and compound stability considerations.

    Science.gov (United States)

    de Beer, Dalene; Malherbe, Christiaan J; Beelders, Theresa; Willenburg, Elize L; Brand, D Jacobus; Joubert, Elizabeth

    2015-02-13

    Aspalathin and nothofagin, the major dihydrochalcones in rooibos (Aspalathus linearis), are valuable bioactive compounds, but their bioactivity has not been fully elucidated. Isolation of these compounds using high-performance countercurrent chromatography (HPCCC), a gentle, support-free, up-scalable technique, offers an alternative to synthesis for obtaining sufficient amounts. An HPLC-DAD method was adapted to allow rapid (16 min from injection to injection) quantification of the four major compounds (aspalathin, nothofagin, isoorientin, orientin) during development of the isolation protocol. The traditional shake-flask method, used to determine distribution constants (K(D)) for target compounds, was also adapted to obtain higher repeatability. Green rooibos leaves with a high aspalathin and nothofagin content were selected as source material. Sample loading of the polyphenol-enriched extract was limited due to constituents with emulsifying properties, but could be increased by removing ethanol-insoluble matter. Furthermore, problems with degradation of aspalathin during HPCCC separation and further processing could be limited by acidifying the HPCCC solvent system. Aspalathin was shown to be fairly stable at pH 3 (91% remaining after 29 h) compared to pH 7 (45% remaining after 29 h). Aspalathin and nothofagin with high purities (99% and 100%, respectively) were obtained from HPCCC fractions after semi-preparative HPLC.

  18. Preparative Separation of Sulfur-Containing Diketopiperazines from Marine Fungus Cladosporium sp. Using High-Speed Counter-Current Chromatography in Stepwise Elution Mode

    Directory of Open Access Journals (Sweden)

    Binbin Gu

    2015-01-01

    Full Text Available High-speed counter-current chromatography (HSCCC was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs (including two new compounds cladosporin A (1 and cladosporin B (3, and a known compound haematocin (2 from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v and (2:1:2:1, v/v, in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was performed on 300 mg of crude sample yielding 26.7 mg of compound 3 at a purity of over 95%, 53.6 mg of a mixture of compounds 1 and 2, which was further separated by preparative-HPLC yielding 14.3 mg of compound 1 and 25.4 mg of compound 2 each at a purity of over 95%. Their structures were established by spectroscopic methods. The sulfur-containing DKPs suppressed the proliferation of hepatocellular carcinoma cell line HepG2. The present work represents the first application of HSCCC in the efficient preparation of marine fungal natural products.

  19. Preparative separation of sulfur-containing diketopiperazines from marine fungus Cladosporium sp. using high-speed counter-current chromatography in stepwise elution mode.

    Science.gov (United States)

    Gu, Binbin; Zhang, Yanying; Ding, Lijian; He, Shan; Wu, Bin; Dong, Junde; Zhu, Peng; Chen, Juanjuan; Zhang, Jinrong; Yan, Xiaojun

    2015-01-09

    High-speed counter-current chromatography (HSCCC) was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs) (including two new compounds cladosporin A (1) and cladosporin B (3), and a known compound haematocin (2)) from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v) and (2:1:2:1, v/v), in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was performed on 300 mg of crude sample yielding 26.7 mg of compound 3 at a purity of over 95%, 53.6 mg of a mixture of compounds 1 and 2, which was further separated by preparative-HPLC yielding 14.3 mg of compound 1 and 25.4 mg of compound 2 each at a purity of over 95%. Their structures were established by spectroscopic methods. The sulfur-containing DKPs suppressed the proliferation of hepatocellular carcinoma cell line HepG2. The present work represents the first application of HSCCC in the efficient preparation of marine fungal natural products.

  20. Separation and purification of neohesperidin from the albedo of Citrus reticulata cv. Suavissima by combination of macroporous resin and high-speed counter-current chromatography.

    Science.gov (United States)

    Zhang, Jiukai; Zhu, Xiaoyan; Luo, Fenglei; Sun, Chongde; Huang, Jianzhen; Li, Xian; Chen, Kunsong

    2012-01-01

    In this article, a simple and efficient protocol for rapid preparation and separation of neohesperidin from the albedo of Citrus reticulata cv. Suavissima was established by the combination of macroporous resin column chromatography and high-speed counter-current chromatography (HSCCC). Six types of resin were investigated by adsorption and desorption tests, and D101 macroporous resin was selected for the first cleaning-up procedure, in which 55% aqueous ethanol was used to elute neohesperidin. After treatment with D101 resin, the neohesperidin purity increased 11.83-fold from 4.92% in the crude extract to 58.22% in the resin-refined sample, with a recovery of 68.97%. The resin-refined sample was directly subjected to HSCCC purification with a two-phase solvent system composed of ethyl acetate-n-butanol-water (4:1:5, v/v), and 23.6 mg neohesperidin with 97.47% purity was obtained from 60 mg sample in only one run. The recovery of neohesperidin in HSCCC separation procedure was 65.85%. The chemical structure of the purified neohesperidin was identified by both HPLC and LC-MS. The established purification process will be helpful for further characterization and utilization of Citrus neohesperidin.

  1. Investigating the pathway for the photochemical formation of VOCs in presence of an organic monolayer at the air/water interface.

    Science.gov (United States)

    Tinel, Liselotte; Rossignol, Stéphanie; Ciuraru, Raluca; George, Christian

    2015-04-01

    Investigating the pathway for the photochemical formation of VOCs in presence of an organic monolayer at the air/water interface. Liselotte Tinel, Stéphanie Rossignol, Raluca Ciuraru and Christian George Université de Lyon, Université Lyon 1, CNRS, UMR5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, Villeurbanne, F-69626, France Recently the surface microlayer (SML) has received growing attention for its role in the deposition and emission of trace gases. This SML is presumably a highly efficient environment for photochemical reactions thanks to its physical and chemical properties, showing enrichment in chromophores [1]. Still, little is known about the possible photochemical processes that could influence the emission and deposition of volatile organic compounds (VOCs) in the SML. A recent study underlines the particularity of the presence of an organic microlayer, showing enhanced formation of peptide bonds at the air-water interface, although this reaction is thermodynamically disfavoured in bulk water [2]. Also, emissions of small gas phase carbonyl compounds formed photochemically by dissolved organic matter have been measured above natural water and glyoxal, for example, measured above the open ocean is thought to be photochemically produced [3, 4]. This study presents the results of a set of laboratory studies set up in order to better understand the role of the SML in the photochemical production of VOCs. Recently, our group has shown the formation of VOCs by light driven reactions in a small quartz reactor (14mL) containing aqueous solutions of humic acids (HA) in the presence of an organic (artificial or natural) microlayer [5]. The main VOCs produced were oxidized species, such as aldehydes, ketones and alcohols, as classically can be expected by the oxidation of the organics present at the interface initiated by triplet excited chromophores present in the HA. But also alkenes, dienes, including isoprene and

  2. Performances of lateral flow biological aerated filter in treating domestic wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-jing; LONG Teng-rui; CAO Yan-xiao

    2006-01-01

    A new biological aerated filter--lateral flow biological aerated filter(LBAF) is developed.The effects of air/water ratio,hydraulic loading and the length of LBAF on pollutants removal efficiency are tested.The results show that under optimal technological conditions when hydraulic loading is 0.43 m3 m(2 h(1 and air/water ratio is 10:1,the average removal efficiencies of COD,SS,NH3-N,and TN reach 88.01%,95.18%,78.97% and 52.58%,respectively.An LBAF has a large pollutants handling capacity; is less liable to be blocked,and has a longer operation cycle in comparison with a traditional BAF.

  3. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    Directory of Open Access Journals (Sweden)

    Jafari Mohammad Javad

    2012-12-01

    Full Text Available Abstract The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p 3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  4. A study on the counter current and cocurrent annular flow critical heat flux under low flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol

    1998-02-15

    Empirical and phenomenological investigations have been performed for countercurrent and cocurrent annular flow critical heat fluxes(CHFs) under low flow conditions. The CHF characteristics on finned surfaces were also examined by experiments and analyses for finned and unfinned geometries. A new form of C{sub w}{sup 2} in the Wallis flooding correlation was proposed for a general use in predicting the flooding limited CHF at tubes, annuli and rectangular channels under zero and very low flow conditions. The suggested correlation showed reasonable predictions compared to the measured CHF with an root-mean-square(RMS) error of 18.8%. A physical model for the prediction of a CHF location at a zero inlet flow condition was improved to take into account entrainment from the liquid film and to extend the applicable range to subcooled inlet flow conditions. The improved model showed reasonable agreements with the Katto data, and provided details of the CHF mechanism due to flooding. It was analytically confirmed that the flooding is a triggering mechanism of a countercurrent annular flow CHF under zero and very low flow conditions. It was also revealed that the heat flux effect such as the nucleation induced entrainment in the liquid film should be considered for the analysis of a flooding limited CHF, especially in small L/D geometry. In addition, an attempt was made to predict CHF values by applying the improved model with predetermined CHF locations. The results showed that the predictions by the improved physical model agreed reasonably with the experimental data. Annular flow hydrodynamic models of Whalley, Levy and Katto, which were developed for high flow conditions, were compared with available low flow CHF data to make out the applicability of the models to low flow conditions. As a result, it was found that Katto model, which improved the fault of Whally and Levy models, could be applied to predict low flow CHF with some improvements although the model

  5. Gas transfer velocities for quantifying methane, oxygen and other gas fluxes through the air-water interface of wetlands with emergent vegetation

    Science.gov (United States)

    Poindexter, C.; Variano, E. A.

    2012-12-01

    Empirical models for the gas transfer velocity, k, in the ocean, lakes and rivers are fairly well established, but there are few data to predict k for wetlands. We have conducted experiments in a simulated emergent marsh in the laboratory to explore the relationship between k, wind shear and thermal convection. Now we identify the implications of these results for gas transfer in actual wetlands by (1) quantifying the range of wind conditions in emergent vegetation canopies and the range of thermal convection intensities in wetland water columns, and (2) describing the non-linear interaction of these two stirring forces over their relevant ranges in wetlands. We measured mean wind speeds and wind speed variance within the shearless region of a Schoenoplectus-Typha marsh canopy in the Sacramento-San Joaquin Delta (Northern California, USA). The mean wind speed within this region, , is significantly smaller than wind above the canopy. Based on our laboratory experiments, for calm or even average wind conditions in this emergent marsh k600 is only on the order 0.1 cm hr-1 (for neutrally or stably stratified water columns). We parameterize unstable thermal stratification and the resulting thermal convection using the heat flux through the air-water interface, q. We analyzed a water temperature record for the Schoenoplectus-Typha marsh to obtain a long-term heat flux record. We used these heat flux data along with short-term heat flux data from other wetlands in the literature to identify the range of the gas transfer velocity associated with thermal convection in wetlands. The typical range of heat fluxes through water columns shaded by closed emergent canopies (-200 W m-2 to +200 W m-2) yields k600 values of 0.5 - 2.5 cm hr-1 according to the model we developed in the laboratory. Thus for calm or average wind conditions, the gas transfer velocity associated with thermal convection is significantly larger than the gas transfer velocity associated with wind shear

  6. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Science.gov (United States)

    Sabanskis, A.; Virbulis, J.

    2016-04-01

    Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  7. Experiments on the transition from stratified to slug flow in multiphase pipe flow

    Energy Technology Data Exchange (ETDEWEB)

    Kristiansen, Olav

    2004-12-01

    Severe slugging is reported from some field operations, where an increase in the production rate leads to a transition from steady stratified flow to slug flow in the pipeline. The slugs can be longer than anticipated for hydrodynamic slugging and the flow transients can then be a limitation for the production capacity. The objective was to perform a study on the flow pattern transition from stratified to slug flow. A particular point of interest was the possible occurrence of metastable flow and large initial slugs at elevated pressures. New data have been acquired in an experimental investigation of the transition from stratified to slug flow in horizontal and near-horizontal pipes at atmospheric and pressurised conditions. The experiments were performed with two-phase gas liquid and three-phase gas-liquid-liquid flows. Two flow facilities were used the NTNU Multiphase Flow Laboratory (short flow loop) and the SINTEF Multi-phase Flow Laboratory (long flow loop). Hold-up and pressure drop were measured, and flow patterns were determined visually and by evaluation of hold-up time traces. The following parameters were varied: 1) Inlet flow condition by variation of inlet pipe inclination. 2) System pressure (gas density). 3) Test section inclination (horizontal and near-horizontal). 4) Water cut. 5) Gas and liquid flow rates. 6) Pipe length. Slug flow or stratified flow was introduced upstream to promote either early or delayed transition to slug flow in the test section. A time series analysis was performed on the hold-up time traces, and average and distribution slug characteristics are reported, e.g. slug frequency, bubble propagation velocity, slug fraction, slug length, and growth rate. The results have been compared with steady state model predictions. The work consists of the following parts. 1) An initial study was performed at atmospheric air-water conditions in a short pipe. 2) Experiments at atmospheric and elevated pressures were performed in the medium

  8. Intelligence on the second stage. 'Air-On' plus air/water heat pump. Cheap air conditioning technology; Intelligenz der zweiten Stufe. 'Air-On' plus Luft/Wasser-Waermepumpe. Preiswerte Raumklimatechnik

    Energy Technology Data Exchange (ETDEWEB)

    Genath, Bernd

    2011-07-15

    It is hard to believe: The heating technique still holds thoughtful surprises. Based on the idea and based on the physics of the heating technology, the company Air-On AG (Cham, Switzerland). For the renovation of old buildings, this company used a second stage of a heat pump to replace old heaters. This second stage is a Peltier element and exclusively tempers a individual room decentrally. The second stage has a better coefficiency of performance than the first stage such as an air / water heat pump.

  9. C1-Continuous relative permeability and hybrid upwind discretization of three phase flow in porous media

    Science.gov (United States)

    Lee, S. H.; Efendiev, Y.

    2016-10-01

    Three-phase flow in a reservoir model has been a major challenge in simulation studies due to slowly convergent iterations in Newton solution of nonlinear transport equations. In this paper, we examine the numerical characteristics of three-phase flow and propose a consistent, "C1-continuous discretization" (to be clarified later) of transport equations that ensures a convergent solution in finite difference approximation. First, we examine three-phase relative permeabilities that are critical in solving nonlinear transport equations. Three-phase relative permeabilities are difficult to measure in the laboratory, and they are often correlated with two-phase relative permeabilities (e.g., oil-gas and water-oil systems). Numerical convergence of non-linear transport equations entails that three-phase relative permeability correlations are a monotonically increasing function of the phase saturation and the consistency conditions of phase transitions are satisfied. The Modified Stone's Method II and the Linear Interpolation Method for three-phase relative permeability are closely examined for their mathematical properties. We show that the Linear Interpolation Method yields C1-continuous three-phase relative permeabilities for smooth solutions if the two phase relative permeabilities are monotonic and continuously differentiable. In the second part of the paper, we extend a Hybrid-Upwinding (HU) method of two-phase flow (Lee, Efendiev and Tchelepi, ADWR 82 (2015) 27-38) to three phase flow. In the HU method, the phase flux is divided into two parts based on the driving forces (in general, it can be divided into several parts): viscous and buoyancy. The viscous-driven and buoyancy-driven fluxes are upwinded differently. Specifically, the viscous flux, which is always co-current, is upwinded based on the direction of the total velocity. The pure buoyancy-induced flux is shown to be only dependent on saturation distributions and counter-current. In three-phase flow, the

  10. Study on the Separation of Monoterpenes from Piper nigrum L·by High-speed Counter-current Chromatography%高速逆流色谱分离制备白胡椒中单萜类化合物

    Institute of Scientific and Technical Information of China (English)

    蒋志国; 陈文学; 刘四新

    2011-01-01

    Three monoterpenes were prepared, isolated and purified from Piper nigrum L.. by high-speed counter-current chromatography (HSCCC) . A two-phase solvent system composed of TBME-methanol-water (2: 1: 1, v/v/v) was used. The upper phase was stationary phase and lower phase was mobile phase. By one-step elution, under the conditions of a flow rate of 2.5 mL/min and 900 r/min, 35 mg of 3,7-dimethyloct-2E-en-1,6,7-triol, 55 mg of p-menthane-l ,2,8-triol-2-O-β-D-glucopyranoside and 40 mg of 5-hydroxy bornyl-2-O-β-D-glucopyranoside was obtained from 2. 76 mg of the butanol extract of Piper nigrum L. , the purities was over 95.0% detected by high performance liquid chromatography with evaporative light scattering detection. The obtained fractions were analyzed by high performance liquid chromatography ( HPLC), and identified by mass spectrometry ( MS), 1 H-nuclear magnetic resonance (NMR) and 13C-NMR. The results indicated that HSCCC is a powerful technique for the purification of monoterpenes from Piper nigrum L. with high productive capacity and high efficiency.%应用高速逆流色谱法分离制备了白胡椒中3种单萜类化合物.以V(叔丁基甲基醚):V(甲醇):V(水)=2:1:1为两相溶剂系统,上相为固定相,下相为流动相,在主机转速900 r/rain、流动相流速2.5 mI/min条件下,从2.76 g样品中一步分离制备得到3,7-二甲基-2-辛烯-1,6,7-三醇35 mg,对薄荷烷-1,2,8-三醇-2-O-β-D 葡萄糖苷55mg,5-羟基龙脑-2-O-β-D葡萄糖苷40mg,经高效液相蒸发光散射检测器(HPLC-ELSD)检测纯度均达95.0%以上,各化合物结构经质谱和核磁共振氢谱、碳谱鉴定.研究结果表明,利用该方法可以对白胡椒中的单萜类化合物进行快速的分离和纯化,且制备量大,分离效率高.

  11. Isolation and preparation of gallic acid from Terminalia chebula Retz. with high-speed counter-current chromatography%高速逆流色谱法分离制备中药诃子中的没食子酸

    Institute of Scientific and Technical Information of China (English)

    李忠琴; 李秋云; 江兴龙; 张坤; 关瑞章

    2014-01-01

    A separation method based on high-speed counter-current chromatography ( HSCCC)has been established for the isolation and preparation of gallic acid from the ethanol extract of Terminalia chebula Retz. After comparing five kinds of solvent protocols of HSCCC, the two-phase system of n-hexane-ethyl acetate-methanol-water(1:5:1:5,v/v/v/v)was final-ly chosen as the operating solvent of HSCCC for the separation of gallic acid,in which the low-er phase was used as the mobile phase and the upper phase as stationary phase. The detection in the experiments was performed with an ultraviolet detector at 254 nm. Under the conditions of rotation speed of 850 r/min,lower phase flow rate of 2 mL/min,four peaks(Ⅰ/Ⅱ/Ⅲ/Ⅳ) were displayed on HSCCC chromatogram. Among them,only peak Ⅲ contained a large amount of gallic acid( about 96. 40%),which was confirmed by electrospray ionization mass spectrom-etry( ESI-MS)and high performance liquid chromatographic( HPLC)analysis. As much as 8. 6 mg of gallic acid was obtained from 100 mg of the ethanol extract of Terminalia chebula Retz., indicating the method is simple,robust and efficient for the preparation of gallic acid.%利用高速逆流色谱法从100 mg诃子醇提物中一次性分离制备得到8.6 mg没食子酸。通过分析型高速逆流色谱对5种溶剂系统进行筛选,确定以正己烷-乙酸乙酯-甲醇-水(体积比为1:5:1:5)为两相溶剂体系并放大到制备型上,以上相为固定相,下相为流动相,在主机转速850 r/min、流动相流速2 mL/min、检测波长254 nm 的条件下进行分离制备,获得4个分离峰(组分Ⅰ、Ⅱ、Ⅲ、Ⅳ)。经高效液相色谱检测,按照面积归一法计算,其中组分Ⅲ的纯度达96.40%。经电喷雾电离质谱分析,并结合与没食子酸标准品的高效液相色谱测定结果的对比,确定组分Ⅲ为没食子酸。该方法简便、快速、重复性好,适合于诃子中没食子酸的分离制备。

  12. 逆流萃取—反相高效液相色谱法测定川芎中川芎嗪的含量%Determination of Tetramethylpyrazine in Ligusticum Chuanxiong Hort by RP-HPLC Coupled with Countercurrent Extraction

    Institute of Scientific and Technical Information of China (English)

    孙新国; 王涛; 朱景申

    2001-01-01

    An analytical method for determination of tetramethylpyrazine (TMP) in ligusticum chuanxiong hort by RP-HPLC coupled with countercurrent extraction used for the preconcentration of trace TMP was established. The column was packed with Zorbax ODS (250 mm×4 mm,5 μm). The mobile phase consisted of methanol water (1 % acetic acid)(35∶65),the flow rate was 0.8 ml/min and detection was performed at 300 nm. The calibration curves showed good linearity over the range of 0.41 μg/ml to 4.1 μg/ml,γ=0.9993,the recoveries were 92.3 %. The method was simple,fast,sensitive and accurate and could be applied to the analysis of ligusticum chuanxiong hort. The results showed that the content of TMP in ligusticum chuanxionghort were different with different sources.%采用逆流萃取与反相高效液相色谱相结合的方法,富集并测定了川芎中川芎嗪的含量。色谱柱:Zorbax ODS柱,流动相:甲醇:水(1%醋酸)=35:65,流速:0.8 ml/min,检测波长:300 nm,线性范围:0.41 μg/ml~4.1 μg/ml,r=0.9993,回收率:92.3%。方法简便、快速、灵敏。用此法对购自不同地区的川芎进行了分析,结果提示:市售川芎的川芎嗪含量差异较大。

  13. On-line coupling of counter-current chromatography and macroporous resin chromatography for continuous isolation of arctiin from the fruit of Arctium lappa L.

    Science.gov (United States)

    Guo, Mengzhe; Liang, Junling; Wu, Shihua

    2010-08-13

    In this work, we have developed a novel hybrid two-dimensional counter-current chromatography and liquid chromatography (2D CCC x LC) system for the continuous purification of arctiin from crude extract of Arctium lappa. The first dimensional CCC column has been designed to fractionalize crude complex extract into pure arctiin effluent using a one-component organic/salt-containing system, and the second dimensional LC column has been packed with macroporous resin for on-line adsorption, desalination and desorption of arctiin which was effluent purified from the first CCC dimension. Thus, the crude arctiin mixture has been purified efficiently and conveniently by on-line CCC x LC in spite of the use of a salt-containing solvent system in CCC separation. As a result, high purity (more than 97%) of arctiin has been isolated by repeated injections both using the ethyl acetate-8% sodium chloride aqueous solution and butanol-1% sodium chloride aqueous solution. By contrast with the traditional CCC processes using multi-component organic/aqueous solvent systems, the present on-line CCC x LC process only used a one-component organic solvent and thus the solvent is easier to recover and regenerate. All of used solvents such as ethyl acetate, n-butanol and NaCl aqueous solution are low toxicity and environment-friendly. Moreover, the lower phase of salt-containing aqueous solution used as mobile phase, only contained minor organic solvent, which will save much organic solvent in continuous separation. In summary, our results indicated that the on-line hybrid 2D CCC x LC system using one-component organic/salt-containing aqueous solution is very promising and powerful tool for high-throughput purification of arctiin from fruits of A. lappa.

  14. Isolation and purification of lignans from Schisandra chinensis by combination of silica gel column and high-speed counter-current chromatography

    Directory of Open Access Journals (Sweden)

    Sun Yu

    2013-01-01

    Full Text Available Silica gel column combined with high-speed counter-current chromatography separation was successfully applied to the separation of schizandrin (I, angeloylgomisin H (II, gomisin A (III, schisantherin C (IV, deoxyschizandrin (V, γ-schisandrin (VI and schisandrin C (VII from the fruits of Schisandra chinensis (Turcz. Baillon. The petroleum ether extracts of the fruits of S. chinensis were pre-separated first on a silica gel column and divided into two fractions as sample 1 and sample 2. 260 mg of sample 1 was separated by HSCCC using petroleum ether-ethyl acetate-methanol-water (10:8:10:8, v/v as the two-phase solvent system and 18.2 mg of schizandrin, 15.7 mg of angeloylgomisin H, 16.5 mg of gomisin A and 16.7 mg of schisantherin C were obtained. 230 mg of sample 2 was separated using petroleum ether-ethyl acetate-methanol-water (10:0.5:10:1, v/v as the two-phase solvent system and 19.7 mg of deoxyschizandrin, 23.4 mg of γ-schisandrin and 18.2 mg of schisandrin C were obtained. The purities of the separated compounds were all over 94% as determined by HPLC. The chemical structures of these compounds were confirmed by ESI-MS and 1H NMR. [Acknowledgments. Natural Science Foundation of China (20872083, scientific and technological major special project (2010ZX09401-302-5-12 and the Key Science and Technology Program of Shandong Province (BS2009SW047

  15. Circulating ultrasound-assisted extraction, countercurrent chromatography, and liquid chromatography for the simultaneous extraction, isolation, and analysis of the constituents of Uncaria tomentosa.

    Science.gov (United States)

    Zhang, Yuchi; Liu, Chunming; Qi, Yanjuan; Li, Sainan; Pan, Yan; Li, Yuchun

    2015-04-01

    A hyphenated automated technique for the online extraction, isolation, analysis, and identification of natural organic compounds was established. Circulating ultrasound-assisted extraction (CUAE) was coupled with countercurrent chromatography (CCC), high performance liquid chromatography (HPLC), and a diode array detector (DAD). This approach was applied to the fractionation and purification of alkaloids from Uncaria tomentosa. A biphasic solvent system of chloroform-methanol-water (6:4:5, v:v:v) was used for the CUAE and CCC separation of compounds from 500 g of U. tomentosa. Two CUAE/CCC/HPLC/DAD modes were established. Either the upper aqueous phase or the lower organic phase of the solvent system could be used as the extraction solvent. The target compounds were extracted by CUAE, and the extract was pumped into a sample loop before being directly injected into the CCC column, or pre-purified using a flash chromatography column before injection. The target compounds were eluted using either the organic or aqueous phase of the solvent system and the fractions were monitored using a UV detector. The target fractions were collected by a sample loop via a six-port valve, and analyzed by HPLC/DAD for purity and structural identification. This system isolated of 8.2mg, 7.4 mg, and 12.9 mg of rhynchophylline, corynoxine, and corynoxine B with HPLC purities of 96.15%, 95.34%, and 95.49%, respectively via the first mode; and isolated 26.6 mg, 24.6 mg, and 45.3mg of rhynchophylline, corynoxine, and corynoxine B with a HPLC purities of 98.22%, 97.18%, and 97.93% via the second mode.

  16. Separation and purification of isorhamnetin 3-sulphate from Flaveria bidentis (L.) Kuntze by counter-current chromatography comparing two kinds of solvent systems.

    Science.gov (United States)

    Xie, Qianqian; Yin, Li; Zhang, Guoliang; Wei, Yun

    2012-01-01

    The first preparative separation of a flavonoid sulphate isorhamnetin 3-sulphate from Flaveria bidentis (L.) Kuntze by counter-current chromatography (CCC) was presented. Two kinds of solvent systems were used. A conventional organic/aqueous solvent system n-butanol-ethyl acetate-water (4:1:5, v/v) was used, yielding isorhamnetin 3-sulphate 2.0 mg with a purity of 93.4% from 83 mg of pre-enriched crude extract obtained from 553 mg ethanol extract by macroporous resin. A one-component organic/salt-containing system composed of n-butanol-0.25% sodium chloride aqueous solution (1:1, v/v) was also used, and the LC column packed with macroporous resin has been employed for desalination of the target compound purified from CCC. As a result, 2.1 mg of isorhamnetin 3-sulphate with a purity of over 97% has been isolated from 402 mg of crude extract without pre-enrichment. Compared with the conventional organic/aqueous system, the one-component organic/salt-containing aqueous system was more suitable for the separation of isorhamnetin 3-sulphate, and purer target compound was obtained from the crude extract without pre-enrichment using the new solvent system. The chemical structure was confirmed by ESI-MS and (1)H, (13)C NMR. In summary, our results indicated that CCC using one-component organic/salt-containing aqueous solution is very promising and powerful for high-throughput purification of isorhamnetin 3-sulphate from Flaveria bidentis (L.) Kuntze.

  17. Separation of chlorogenic acid and concentration of trace caffeic acid from natural products by pH-zone-refining countercurrent chromatography.

    Science.gov (United States)

    Lu, Yuanyuan; Dong, Genlai; Gu, Yanxiang; Ito, Yoichiro; Wei, Yun

    2013-07-01

    Chlorogenic acid and caffeic acid were selected as test samples for separation by the pH-zone-refining countercurrent chromatography (CCC). The separation of these test samples was performed with a two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/water at a volume ratio of 4:1:5 v/v/v where trifluoroacetic acid (TFA; 8 mM) was added to the organic stationary phase as a retainer and NH4 OH (10 mM) to the aqueous mobile phase as an eluter. Chlorogenic acid was successfully separated from Flaveria bidentis (L.) Kuntze (F. bidentis) and Lonicerae Flos by pH-zone-refining CCC, a slightly polar two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/n-butanol/water at a volume ratio of 4:1:1:5 v/v/v/v was selected where TFA (3 mM) was added to the organic stationary phase as a retainer and NH4 OH (3 mM) to the aqueous mobile phase as an eluter. A 16.2 mg amount of chlorogenic acid with the purity of 92% from 1.4 g of F. bidentis, and 134 mg of chlorogenic acid at the purity of 99% from 1.3 g of crude extract of Lonicerae Flos have been obtained. These results suggest that pH-zone-refining CCC is suitable for the isolation of the chlorogenic acid from the crude extracts of F. bidentis and Lonicerae Flos.

  18. A novel 9 × 9 map-based solvent selection strategy for targeted counter-current chromatography isolation of natural products.

    Science.gov (United States)

    Liang, Junling; Meng, Jie; Wu, Dingfang; Guo, Mengzhe; Wu, Shihua

    2015-06-26

    Counter-current chromatography (CCC) is an efficient liquid-liquid chromatography technique for separation and purification of complex mixtures like natural products extracts and synthetic chemicals. However, CCC is still a challenging process requiring some special technical knowledge especially in the selection of appropriated solvent systems. In this work, we introduced a new 9 × 9 map-based solvent selection strategy for CCC isolation of targets, which permit more than 60 hexane-ethyl acetate-methanol-water (HEMWat) solvent systems as the start candidates for the selection of solvent systems. Among these solvent systems, there are clear linear correlations between partition coefficient (K) and the system numbers. Thus, an appropriate CCC solvent system (i.e., sweet spot for K = 1) may be hit by measurement of k values of the target only in two random solvent systems. Besides this, surprisingly, we found that through two sweet spots, we could get a line ("Sweet line") where there are infinite sweet solvent systems being suitable for CCC separation. In these sweet solvent systems, the target has the same partition coefficient (K) but different solubilities. Thus, the better sweet solvent system with higher sample solubility can be obtained for high capacity CCC preparation. Furthermore, we found that there is a zone ("Sweet zone") where all solvent systems have their own sweet partition coefficients values for the target in range of 0.4 natural products as standards and further confirmed by isolation of several targets including honokiol and magnolol from the extracts of Magnolia officinalis Rehd. Et Wils and tanshinone IIA from Salvia miltiorrhiza Bunge. In practice, it is much easier to get a suitable solvent system only by making a simple screening two to four HEMWat two-phase solvent systems to obtain the sweet line or sweet zone without special knowledge or comprehensive standards as references. This is an important advancement for solvent system selection

  19. Performance comparison of three types of high-speed counter-current chromatographs for the separation of components of hydrophilic and hydrophobic color additives.

    Science.gov (United States)

    Weisz, Adrian; Ito, Yoichiro

    2011-09-09

    The performance of three types of high-speed counter-current chromatography (HSCCC) instruments was assessed for their use in separating components in hydrophilic and hydrophobic dye mixtures. The HSCCC instruments compared were: (i) a J-type coil planet centrifuge (CPC) system with a conventional multilayer-coil column, (ii) a J-type CPC system with a spiral-tube assembly-coil column, and (iii) a cross-axis CPC system with a multilayer-coil column. The hydrophilic dye mixture consisted of a sample of FD&C Blue No. 2 that contained mainly two isomeric components, 5,5'- and 5,7'-disulfonated indigo, in the ratio of ∼7:1. The hydrophobic dye mixture consisted of a sample of D&C Red No. 17 (mainly Sudan III) and Sudan II in the ratio of ∼4:1. The two-phase solvent systems used for these separations were 1-butanol/1.3M HCl and hexane/acetonitrile. Each of the three instruments was used in two experiments for the hydrophilic dye mixture and two for the hydrophobic dye mixture, for a total of 12 experiments. In one set of experiments, the lower phase was used as the mobile phase, and in the second set of experiments, the upper phase was used as the mobile phase. The results suggest that: (a) use of a J-type instrument with either a multilayer-coil column or a spiral-tube assembly column, applying the lower phase as the mobile phase, is preferable for separating the hydrophilic components of FD&C Blue No. 2; and (b) use of a J-type instrument with multilayer-coil column, while applying either the upper phase or the lower phase as the mobile phase, is preferable for separating the hydrophobic dye mixture of D&C Red No. 17 and Sudan II.

  20. Efficient Preparation of Streptochlorin from Marine Streptomyces sp. SYYLWHS-1-4 by Combination of Response Surface Methodology and High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Lin Li

    2016-05-01

    Full Text Available Since first isolated from the lipophilic extract of Streptomyces sp. SF2583, streptochlorin, has attracted a lot of attention because of its various pharmacological properties, such as antibiotic, antiallergic, antitumor, and anti-inflammatory activities. For the efficient preparation of streptochlorin from a producing strain Streptomyces sp. SYYLWHS-1-4, we developed a combinative method by using response surface methodology (RSM and high-speed counter-current chromatography (HSCCC. In the fermentation process, we used RSM to optimize the condition for the efficient accumulation of streptochlorin, and the optimal parameters were: yeast extract 1.889 g/L, soluble starch 8.636 g/L, K2HPO4 0.359 g/L, CaCl2 2.5 g/L, MgSO4 0.625 g/L, marine salt 25 g/L, medium volume 50%, initial pH value 7.0, temperature 27.5 °C, which enhanced streptochlorin yield by 17.7-fold. During the purification process, the preparative HSCCC separation was performed using a petroleum ether–ethyl acetate–methanol–water (9:0.8:5:5, v/v/v/v biphasic solvent system, where 300 mg of crude sample yielded 16.5 mg streptochlorin with over 95% purity as determined by UPLC. Consequently, the combination method provided a feasible strategy for highly effective preparation of streptochlorin, which ensured the supply of large amounts of streptochlorin for in vivo pharmacological assessments or other requirements.