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Sample records for superheated liquid layer

  1. Surface boiling of superheated liquid

    Energy Technology Data Exchange (ETDEWEB)

    Reinke, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-01-01

    A basic vaporization mechanism that possibly affects the qualitative and quantitative prediction of the consequences of accidental releases of hazardous superheated liquids was experimentally and analytically investigated. The studies are of relevance for the instantaneous failure of a containment vessel filled with liquefied gas. Even though catastrophical vessel failure is a rare event, it is considered to be a major technological hazard. Modeling the initial phase of depressurisation and vaporization of the contents is an essential step for the subsequent analysis of the spread and dispersion of the materials liberated. There is only limited understanding of this inertial expansion stage of the superheated liquid, before gravity and atmospheric turbulence begin to dominate the expansion. This work aims at a better understanding of the vaporization process and to supply more precise source-term data. It is also intended to provide knowledge for the prediction of the behavior of large-scale releases by the investigation of boiling on a small scale. Release experiments with butane, propane, R-134a and water were conducted. The vaporization of liquids that became superheated by sudden depressurisation was studied in nucleation-site-free glass receptacles. Several novel techniques for preventing undesired nucleation and for opening the test-section were developed. Releases from pipes and from a cylindrical geometry allowed both linear one-dimensional, and radial-front two-dimensional propagation to be investigated. Releases were made to atmospheric pressure over a range of superheats. It was found that, above a certain superheat temperature, the free surface of the metastable liquid rapidly broke up and ejected a high-velocity vapor/liquid stream. The zone of intense vaporization and liquid fragmentation proceeded as a front that advanced into the test fluids. No nucleation of bubbles in the bulk of the superheated liquid was observed. (author) figs., tabs., refs.

  2. Explosive Boiling of Superheated Cryogenic Liquids

    CERN Document Server

    Baidakov, V G

    2007-01-01

    The monograph is devoted to the description of the kinetics of spontaneous boiling of superheated liquefied gases and their solutions. Experimental results are given on the temperature of accessible superheating, the limits of tensile strength of liquids due to processes of cavitation and the rates of nucleation of classical and quantum liquids. The kinetics of evolution of the gas phase is studied in detail for solutions of cryogenic liquids and gas-saturated fluids. The properties of the critical clusters (bubbles of critical sizes) of the newly evolving gas phase are analyzed for initial st

  3. Dark matter searches using superheated liquids

    Science.gov (United States)

    Manuel, Bou-Cabo; Miguel, Ardid; Ivan, Felis

    2016-07-01

    Direct detection of dark matter is one of the most important topics in modern physics. It is estimated that 22% of universe matter is composed by dark matter in front of 0.4% of ordinary matter like stars, galaxies planets and all kind of known astrophysical objects. Several kinds of experiments are nowadays involved in detection of one of the more accepted particle candidates to be dark matter: WIMPs (Weakly Interacting Massive Particles). These detectors, using several kinds of techniques: Cryogenic semiconductors, scintillation materials like I Na or noble gas chambers among others, are reporting very interesting but inconclusive results. In this paper a review of detectors that are using the superheated liquid technique in bubble chambers in order to detect WIMPs is reported. Basically, we will report about Coupp (Chicagoland observatory for underground particle physics), PICO that is composed by Coupp and Picasso researchers having the aim to build a ton experiment and also about a new detector named MOSCAB (Materia oscura a bolle) that recently published a first results of a test chamber that uses also superheated liquid technique but as a Geyser chamber.

  4. Dark matter searches using superheated liquids

    Directory of Open Access Journals (Sweden)

    Manuel Bou-Cabo

    2016-01-01

    Full Text Available Direct detection of dark matter is one of the most important topics in modern physics. It is estimated that 22% of universe matter is composed by dark matter in front of 0.4% of ordinary matter like stars, galaxies planets and all kind of known astrophysical objects. Several kinds of experiments are nowadays involved in detection of one of the more accepted particle candidates to be dark matter: WIMPs (Weakly Interacting Massive Particles. These detectors, using several kinds of techniques: Cryogenic semiconductors, scintillation materials like I Na or noble gas chambers among others, are reporting very interesting but inconclusive results. In this paper a review of detectors that are using the superheated liquid technique in bubble chambers in order to detect WIMPs is reported. Basically, we will report about Coupp (Chicagoland observatory for underground particle physics, PICO that is composed by Coupp and Picasso researchers having the aim to build a ton experiment and also about a new detector named MOSCAB (Materia oscura a bolle that recently published a first results of a test chamber that uses also superheated liquid technique but as a Geyser chamber.

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

    Science.gov (United States)

    Samkhaniani, N.; Ansari, M. R.

    2017-09-01

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

  6. Discrimination of events in superheated liquid

    Science.gov (United States)

    Archambault, Simon

    2010-02-01

    PICASSO is a Dark Matter search experiment using superheated droplets of C4F10 as the active detector material, suspended in an elastic polymer. If a WIMP (Weakly Interacting Massive Particle) hits a nucleus inside a droplet, the recoiling nucleus will deposit its energy in a heat spike, triggering a phase transition. The setup, installed at SNOLab, 2 km underground, consists of 32 cylindrical detectors of 4.5L. The acoustic signals emitted during a phase transition are recorded by nine piezo-electric transducers mounted on the detector walls and the waveforms are analysed offline. In this way, different types of events can be identified using different variables. One of these variables, which is proportional to the total energy of the acoustic signal, allows discrimination among neutron or WIMP-induced events, background alpha particle induced events and electronic noise; another discrimination variable is constructed from the Fast Fourier Transform of the signal and allows the discrimination of other classes of backgrounds. )

  7. An experimental study of evaporation waves in a superheated liquid

    Science.gov (United States)

    Hill, Larry G.

    1990-01-01

    Evaporation waves in superheated liquids are studied using a rapid-depressurization facility consisting of a vertical glass test cell situated beneath a large, low-pressure reservoir. The objective of this study is to learn more about the physical mechanisms of explosive boiling (of which an evaporation wave is a specific example), as well as properties of the flow it produces.The test cell is initially sealed from the reservoir by a foil diaphragm, and is partially filled with a volatile liquid (Refrigerant 12 or 114). An experiment is initiated by rupturing the diaphragm via a pneumatically driven cutter. The instrumentation consists of fast-response pressure measurements, high-speed motion pictures, and spark-illuminated still photographs. The liquid temperature is typically 20°C; the liquid superheat is controlled by setting the reservoir pressure to values between vacuum and 1 atm. The pressures subsequent to depressurization are very much less than the critical pressure, and the initial temperatures are sufficiently low that, although the test liquid is highly superheated, the superheat limit is not approached. Evaporation waves in which bubble nucleation within the liquid column is suppressed entirely are considered almost exclusively.When the diaphragm is ruptured, the liquid pressure drops to virtually the reservoir value within a few milliseconds. Provided that the liquid superheat so obtained is sufficiently high, the free surface then erupts in a process known as explosive boiling, which is characterized by violent, fine-scale fragmentation of the superheated liquid and extremely rapid evaporation. The explosive boiling process proceeds as a "wavefront" into the liquid column, producing a highspeed, two-phase flow that travels upward into the low-pressure reservoir, emptying the test cell in a few hundred milliseconds. The speed of the wavefront varies between 0.2 and 0.6 m/s, depending on run conditions; the corresponding two-phase flow varies between

  8. a Theoretical Model of a Superheated Liquid Droplet Neutron Detector.

    Science.gov (United States)

    Harper, Mark Joseph

    Neutrons can interact with the atoms in superheated liquid droplets which are suspended in a viscous matrix material, resulting in the formation of charged recoil ions. These ions transfer energy to the liquid, sometimes resulting in the droplets vaporizing and producing observable bubbles. Devices employing this mechanism are known as superheated liquid droplet detectors, or bubble detectors. The basis of bubble detector operation is identical to that of bubble chambers, which have been well characterized by researchers such as Wilson, Glaser, Seitz, and others since the 1950's. Each of the microscopic superheated liquid droplets behaves like an independent bubble chamber. This dissertation presents a theoretical model which considers the three principal aspects of detector operation: nuclear reactions, charged particle energy deposition, and thermodynamic bubble formation. All possible nuclear reactions were examined and those which could reasonably result in recoil ions sufficiently energetic to vaporize a droplet were analyzed in detail. Feasible interactions having adequate cross sections include elastic and inelastic scattering, n-proton, and n-alpha reactions. Ziegler's TRansport of Ions in Matter (TRIM) code was used to calculate the ions' stopping powers in various compounds based on the ionic energies predicted by standard scattering distributions. If the ions deposit enough energy in a small enough volume then the entire droplet will vaporize without further energy input. Various theories as to the vaporization of droplets by ionizing radiation were studied and a novel method of predicting the critical (minimum) energy was developed. This method can be used to calculate the minimum required stopping power for the ion, from which the threshold neutron energy is obtainable. Experimental verification of the model was accomplished by measuring the response of two different types of bubble detectors to monoenergetic thermal neutrons, as well as to neutrons

  9. Wicking of liquid nitrogen into superheated porous structures

    Science.gov (United States)

    Grebenyuk, Yulia; Dreyer, Michael E.

    2016-09-01

    Evaporation in porous elements of liquid-vapor separation devices can affect the vapor-free cryogenic propellant delivery to spacecraft engines. On that account, the capillary transport of a cryogenic liquid subjected to evaporation needs to be understood and assessed. We investigate wicking of liquid nitrogen at saturation temperature into superheated porous media. A novel test facility was built to perform wicking experiments in a one-species system under non-isothermal conditions. A setup configuration enabled to define the sample superheat by its initial position in a stratified nitrogen vapor environment inside the cryostat. Simultaneous sample weight and temperature measurements indicated the wicking front velocity. The mass of the imbibed liquid nitrogen was determined varying the sample superheat, geometry and porous structure. To the author's extent of knowledge, these are the first wicking experiments performed with cryogenic fluids subjected to evaporation using the weight-time measurement technique. A one-dimensional macroscopic model describes the process theoretically. Results revealed that the liquid loss due to evaporation at high sample superheats leads to only a slight imbibition rate decrease. However, the imbibition rate can be greatly affected by the vapor flow created due to evaporation that counteracts the wicking front propagation.

  10. Ginzburg-Landau theory of the superheating field anisotropy of layered superconductors

    Science.gov (United States)

    Liarte, Danilo B.; Transtrum, Mark K.; Sethna, James P.

    2016-10-01

    We investigate the effects of material anisotropy on the superheating field of layered superconductors. We provide an intuitive argument both for the existence of a superheating field, and its dependence on anisotropy, for κ =λ /ξ (the ratio of magnetic to superconducting healing lengths) both large and small. On the one hand, the combination of our estimates with published results using a two-gap model for MgB2 suggests high anisotropy of the superheating field near zero temperature. On the other hand, within Ginzburg-Landau theory for a single gap, we see that the superheating field shows significant anisotropy only when the crystal anisotropy is large and the Ginzburg-Landau parameter κ is small. We then conclude that only small anisotropies in the superheating field are expected for typical unconventional superconductors near the critical temperature. Using a generalized form of Ginzburg Landau theory, we do a quantitative calculation for the anisotropic superheating field by mapping the problem to the isotropic case, and present a phase diagram in terms of anisotropy and κ , showing type I, type II, or mixed behavior (within Ginzburg-Landau theory), and regions where each asymptotic solution is expected. We estimate anisotropies for a number of different materials, and discuss the importance of these results for radio-frequency cavities for particle accelerators.

  11. Correlation Between Superheated Liquid Fragility And Onset Temperature Of Crystallization For Al-Based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Guo J.

    2015-06-01

    Full Text Available Amorphous alloys or metallic glasses have attracted significant interest in the materials science and engineering communities due to their unique physical, mechanical, and chemical properties. The viscous flow of amorphous alloys exhibiting high strain rate sensitivity and homogeneous deformation is considered to be an important characteristic in thermoplastic forming processes performed within the supercooled liquid region because it allows superplastic-like deformation behavior. Here, the correlation between the superheated liquid fragility, and the onset temperature of crystallization for Al-based alloys, is investigated. The activation energy for viscous flow of the liquid is also investigated. There is a negative correlation between the parameter of superheated liquid fragility and the onset temperature of crystallization in the same Al-based alloy system. The activation energy decreases as the onset temperature of crystallization increases. This indicates that the stability of a superheated liquid can affect the thermal stability of the amorphous alloy. It also means that a liquid with a large superheated liquid fragility, when rapidly solidified, forms an amorphous alloy with a low thermal stability.

  12. Nucleation efficiency of R134a as a sensitive liquid for superheated drop emulsion detector

    Indian Academy of Sciences (India)

    Mala Das; R Sarkar; P K Mondal; S Saha; B K Chatterjee; S C Roy

    2010-10-01

    Superheated emulsion detector is known to detect neutrons, γ-rays and other charged particles. The present work includes the study of nucleation efficiency of super-heated drops of one of the CFC-free liquids, R134a (C2H2F4), to fast neutrons, its response to -rays from 241Am and 137Cs and compare its nucleation efficiency with that of R12. The observation indicates that because of the presence of hydrogen, the nucleation efficiency is less in R134a than in R12 in the present neutron energy range of considera-tion. R134a is one of the most environment-friendly, commercially available liquid that is suitable for superheated drop detector, specially in neutron dosimetry and one needs to investigate it in detail.

  13. Microwave super-heated boiling of organic liquids: Origin, effect and application

    NARCIS (Netherlands)

    Chemat, F.; Esveld, E.

    2001-01-01

    This paper reports the state of the art of the microwave super-heated boiling phenomenon. When a liquid is heated by microwaves, the temperature increases rapidly to reach a steady temperature while refluxing. It happens that this steady state temperature can be up to 40 K higher than the boiling po

  14. Superheating Suppresses Structural Disorder in Layered BiI3 Semiconductors Grown by the Bridgman Method

    Energy Technology Data Exchange (ETDEWEB)

    Johns, Paul M.; Sulekar, Soumitra; Yeo, Shinyoung; Baciak, James E.; Bliss, Mary; Nino, Juan C.

    2016-01-01

    The susceptibility of layered structures to stacking faults is a problem in some of the more attractive semiconductor materials for ambient-temperature radiation detectors. In the work presented here, Bridgman-grown BiI3 layered single crystals are investigated to understand and eliminate this structural disorder, which reduces radiation detector performance. The use of superheating gradients has been shown to improve crystal quality in non-layered semiconductor crystals; thus the technique was here explored to improve the growth of BiI3. When investigating the homogeneity of non-superheated crystals, highly geometric void defects were found to populate the bulk of the crystals. Applying a superheating gradient to the melt prior to crystal growth improved structural quality and decreased defect density from the order of 4600 voids per cm3 to 300 voids per cm3. Corresponding moderate improvements to electronic properties also resulted from the superheat gradient method of crystal growth. Comparative measurements through infrared microscopy, etch-pit density, x-ray rocking curves, and sheet resistivity readings show that superheat gradients in BiI3 growth led to higher quality crystals.

  15. Superheating suppresses structural disorder in layered BiI3 semiconductors grown by the Bridgman method

    Science.gov (United States)

    Johns, Paul M.; Sulekar, Soumitra; Yeo, Shinyoung; Baciak, J. E.; Bliss, Mary; Nino, Juan C.

    2016-01-01

    The susceptibility of layered structures to stacking faults is a problem in some of the more attractive semiconductor materials for ambient-temperature radiation detectors. In this work, Bridgman-grown BiI3 layered single crystals are investigated to understand and eliminate structural disorder, which reduces radiation detector performance. The use of superheating gradients has been shown by others to improve crystal quality in non-layered semiconductor crystals (Rudolph et al., 1996) [26]; thus the technique was explored to improve the growth of BiI3. When investigating the homogeneity of non-superheated crystals, highly geometric void defects were found to populate the bulk of the crystals. Applying a superheating gradient to the melt prior to crystal growth improved structural quality and decreased defect density from the order of 4600 voids per cm3 to 300 voids per cm3. Corresponding moderate improvements to electronic properties also resulted from the superheat gradient method of crystal growth. Comparative measurements through infrared microscopy, etch-pit density, X-ray rocking curves, and sheet resistivity readings show that superheat gradients in BiI3 growth led to higher quality crystals.

  16. Microwave-Assisted Superheating and/or Microwave-Specific Superboiling (Nucleation-Limited Boiling of Liquids Occurs under Certain Conditions but is Mitigated by Stirring

    Directory of Open Access Journals (Sweden)

    Anthony Ferrari

    2015-12-01

    Full Text Available Temporary superheating and sustained nucleation-limited “superboiling” of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating and magnitude (of superheating and superboiling vary according to system parameters such as volume of the liquid and the size and shape of the vessel. Both phenomena are mitigated by rapid stirring with an appropriate stir bar and/or with the addition of boiling chips, which provide nucleation sites to support the phase-change from liquid to gas. With proper experimental design and especially proper stirring, the measured temperature of typical organic reaction mixtures heated at reflux will be close to the normal boiling point temperature of the solvent, whether heated using microwave radiation or conventional convective heat transfer. These observations are important to take into consideration when comparing reaction rates under conventional and microwave heating.

  17. Development of device for trapping a superheated liquid drop and life-time measurements of the drop by radiation-induced evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Sawamura, Teruko; Sugiyama, Noriyuki; Homma, Akira; Narita, Masakuni [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering

    1999-08-01

    In this study a detection sensitivity evaluation was made by measuring the life time of a single liquid drop. A device trapping a superheated drop was developed, where a single drop of test liquid was trapped at a specified position and then irradiated. Therefore, the volume of the drop can be measured before the irradiation. Wakeshima originally developed the device, in which a test liquid drop was injected and superheated in a supporting liquid, to measure the limit of superheat of the liquid. Apfel modified Wakeshima's device by applying an acoustic field to be able to trap and decompress a superheated liquid drop. The device in the present study is similar to Apfel's. But the inlet part is cooled because the boiling point of the test liquid is lower than room temperature. In this device the superheated drop of trans-2-butene (C{sub 4}H{sub 8}, boiling point=0.8degC) was exposed to Am-Be neutrons and {sup 60}Co {gamma}-rays and its life time was measured. (author)

  18. Superheated drop neutron spectrometer

    CERN Document Server

    Das, M; Roy, B; Roy, S C; Das, Mala

    2000-01-01

    Superheated drops are known to detect neutrons through the nucleation caused by the recoil nuclei produced by the interactions of neutrons with the atoms constituting the superheated liquid molecule. A novel method of finding the neutron energy from the temperature dependence response of SDD has been developed. From the equivalence between the dependence of threshold energy for nucleation on temperature of SDD and the dependence of dE/dx of the recoil ions with the energy of the neutron, a new method of finding the neutron energy spectrum of a polychromatic as well as monochromatic neutron source has been developed.

  19. Superheated emulsions: neutronics and thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    d`Errico, F. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari]|[Yale Univ., New Haven, CT (United States). School of Medicine; Curzio, G. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari; Nath, R. [Yale Univ., New Haven, CT (United States). School of Medicine; Apfel, R.E. [Yale Univ., New Haven, CT (United States). Dept. of Mechanical Engineering; Dietz, E.; Guldbakke, S.; Siebert, B.R.L. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Egger, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Gualdrini, G.F. [ENEA, Bologna (Italy)

    1997-09-01

    The results of some recent theoretical and experimental investigations on the physics of superheated emulsions are presented. Computational fluid thermodynamics allowed for a detailed description of the temporal and spatial history of the energy deposition process by a charged particle in a superheated liquid. Despite the assumptions it is based upon, this model gives information in agreement with experimental data on bubble nucleation. The experimental findings concern the role of interfacial reactions between drops and emulsifier, the existence of inhibition temperatures for the detector`s response, and the progressive sensitisation to protons. (author).

  20. BOILER-SUPERHEATED REACTOR

    Science.gov (United States)

    Heckman, T.P.

    1961-05-01

    A nuclear power reactor of the type in which a liquid moderator-coolant is transformed by nuclear heating into a vapor that may be used to drive a turbo- generator is described. The core of this reactor comprises a plurality of freely suspended tubular fuel elements, called fuel element trains, within which nonboiling pressurized liquid moderator-coolant is preheated and sprayed through orifices in the walls of the trains against the outer walls thereof to be converted into vapor. Passage of the vapor ovcr other unwetted portions of the outside of the fuel elements causes the steam to be superheated. The moderatorcoolant within the fuel elements remains in the liqUid state, and that between the fuel elements remains substantiaily in the vapor state. A unique liquid neutron-absorber control system is used. Advantages expected from the reactor design include reduced fuel element failure, increased stability of operation, direct response to power demand, and circulation of a minimum amount of liquid moderatorcoolant. (A.G.W.)

  1. Detection in superheated water chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Chienthavorn, O

    1999-11-01

    Superheated water has been used successfully as an eluent in liquid chromatography and has been coupled to various modes of detection, ultraviolet (UV), fluorescence, and nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). A number of compounds were examined on poly(styrene-divinylbenzene) (PS-DVB), polybutadiene (PBD), and octadecylsilyl bonded silica (ODS) column with isothermal and temperature programmes. The PS-DVB column was mostly used throughout the project as it was the most stable. Not only pure water could serve as superheated water mobile phase; inorganic buffered water and ion-pairing reagent with a concentration of 1-3 mM of the buffer and reagent were also exploited. It was shown that the pH could be controlled during the separation without salt precipitation and the separations followed a conventional reversed-phase HPLC method. Results from fluorescence detection showed good separation of a series of vitamins, such as pyridoxine, riboflavin, thiamine, and some analgesics. The relationship of riboflavin using the detection was linear and the detection limit was seven times higher than that of a conventional method. Simultaneous separation and identification using superheated water chromatography-NMR was demonstrated. With using a stop flow method, NMR spectra of model drugs, namely barbiturates, paracetamol, caffeine and phenacetin were obtained and the results agreed with reference spectra, confirming a perfect separation. A demonstration to obtain COSY spectrum of salicylamide was also performed. The method was expanded to the coupling of superheated water LC to NMR-MS. Results from the hyphenated detection method showed that deuteration and degradation happened in the superheated water conditions. The methyl group hydrogens of pyrimidine ring of sulfonamide and thiamine were exchanged with deuterium. Thiamine was decomposed to 4-methyl-5-thiazoleethanol and both were deuterated under the conditions. (author)

  2. Stationary phases for superheated water chromatography

    CERN Document Server

    Saha, S

    2002-01-01

    This project focused on the comparison of conventional liquid chromatography and superheated water chromatography. It examined the differences in efficiency and retention of a range of different stationary phases. Alkyl aryl ketones and eight aromatic compounds were separated on PBD-zirconia, Xterra RP 18, Luna C sub 1 sub 8 (2) and Oasis HLB columns using conventional LC and superheated water chromatography system. The retention indices were determined in the different eluents. On changing the organic component of the eluent from methanol to acetonitrile to superheated water considerable improvements were found in the peak shapes and column efficiencies on the PBD-zirconia and Oasis HLB columns. PS-DVB, PBD-zirconia and Xterra RP 18 columns have been used in efficiency studies. It was found that simply elevating the column temperature did not increase the efficiency of a separation in superheated water chromatography. The efficiency depended on flow rate, injection volume and also mobile phase preheating sys...

  3. Melting of superheated molecular crystals

    Science.gov (United States)

    Cubeta, Ulyana; Bhattacharya, Deepanjan; Sadtchenko, Vlad

    2017-07-01

    Melting dynamics of micrometer scale, polycrystalline samples of isobutane, dimethyl ether, methyl benzene, and 2-propanol were investigated by fast scanning calorimetry. When films are superheated with rates in excess of 105 K s-1, the melting process follows zero-order, Arrhenius-like kinetics until approximately half of the sample has transformed. Such kinetics strongly imply that melting progresses into the bulk via a rapidly moving solid-liquid interface that is likely to originate at the sample's surface. Remarkably, the apparent activation energies for the phase transformation are large; all exceed the enthalpy of vaporization of each compound and some exceed it by an order of magnitude. In fact, we find that the crystalline melting kinetics are comparable to the kinetics of dielectric α-relaxation in deeply supercooled liquids. Based on these observations, we conclude that the rate of non-isothermal melting for superheated, low-molecular-weight crystals is limited by constituent diffusion into an abnormally dense, glass-like, non-crystalline phase.

  4. Nonlinear Instability of Liquid Layers.

    Science.gov (United States)

    Newhouse, Lori Ann

    The nonlinear instability of two superposed viscous liquid layers in planar and axisymmetric configurations is investigated. In the planar configuration, the light layer fluid is bounded below by a wall and above by a heavy semiinfinite fluid. Gravity drives the instability. In the first axisymmetric configuration, the layer is confined between a cylindrical wall and a core of another fluid. In the second, a thread is suspended in an infinite fluid. Surface tension forces drive the instability in the axisymmetric configurations. The nonlinear evolution of the fluid-fluid interface is computed for layers of arbitrary thickness when their dynamics are fully coupled to those of the second fluid. Under the assumption of creeping flow, the flow field is represented by an interfacial distribution of Green's functions. A Fredholm integral equation of the second kind for the strength of the distribution is derived and then solved using an iterative technique. The Green's functions produce flow fields which are periodic in the direction parallel to the wall and have zero velocity on the wall. For small and moderate surface tension, planar layers evolve into a periodic array of viscous plumes which penetrate into the overlying fluid. The morphology of the plumes depends on the surface tension and the ratio of the fluid viscosities. As the viscosity of the layer increases, the plumes change from a well defined drop on top of a narrow stem to a compact column of rising fluid. The capillary instability of cylindrical interfaces and interfaces in which the core thickness varies in the axial direction are investigated. In both the unbounded and wall bounded configurations, the core evolves into a periodic array of elongated fluid drops connected by thin, almost cylindrical fluid links. The characteristics of the drop-link structure depend on the core thickness, the ratio of the core radius to the wall radius, and the ratio of the fluid viscosities. The factors controlling the

  5. LETTER TO THE EDITOR: Homogeneous nucleation for superheated crystal

    Science.gov (United States)

    Iwamatsu, Masao

    1999-01-01

    Homogeneous nucleation of liquid droplets in superheated crystals is considered in order to estimate the maximum superheating of crystals. Using the previously derived universal order parameter model of the crystal-melt transition (Iwamatsu M and Horii K 1996 J. Phys. Soc. Japan 65 2311), it is determined that the catastrophic homogeneous nucleation occurs at 0953-8984/11/1/001/img1, where 0953-8984/11/1/001/img2 is the equilibrium melting point. This numerical estimation is consistent with the results of maximum-superheating experiments.

  6. WIMP searches with superheated droplet detectors Status and Prospects

    CERN Document Server

    Collar, J I; Limagne, D; Miley, H S; Morlat, T; Puibasset, J; Waysand, G

    2001-01-01

    SIMPLE (Superheated Instrument for Massive ParticLE searches) employs superheated droplet detectors (SDDs) to search for Weakly Interacting Massive Particle (WIMP) dark matter. As a result of the intrinsic SDD insensitivity to minimum ionizing particles and high fluorine content of target liquids, competitive WIMP limits were already obtained at the early prototype stage. We comment here on the expected immediate increase in sensitivity of the program and on future plans to exploit this promising technnique.

  7. Drying models and characteristics of thin layer sludge in superheated steam drying%污泥过热蒸汽薄层干燥特性及干燥模型构建

    Institute of Scientific and Technical Information of China (English)

    张绪坤; 孙瑞晨; 王学成; 苏志伟; 曹伟

    2014-01-01

    . The purpose of this study was to investigate the drying characteristics of superheated-steam on a thin layer of sludge. Thin layer drying experiments of sludge samples with different thicknesses under a series of superheated steam temperatures were carried out. Sludge samples were collected in a local wastewater treatment plant after mechanical dewatering. The size of the sludge samples were taken over an area of 100 mm×100 mm, having thicknesses of 2, 4, 6, and 10 mm, respectively. The temperatures of superheated steam were controlled by the amount of the access heaters. The experiments of superheated steam drying were conducted at 160, 200, 240, and 280℃, respectively. Relations between the model parameters and temperature and thickness for the moisture ratio of sludge in relation to drying time were determined. The results showed that sludge samples were not oxidized or burnt after superheated steam drying even at high temperatures. The dense crack and rough surface of sludge during superheated steam drying were beneficial to the drying process. At the beginning of the drying process, the mass of the samples increased due to superheated steam coming in contact with the cold surface of the sludge as the initial temperature of the sludge is close to room temperature (around 20℃). As a result, the drying time of sludge samples to reach a certain moisture content increased. The increase in the mass of condensation water and drying time was greatly influenced by the temperature of superheated steam. As a result, the higher the temperature, the smaller the increase. However, the increase was hardly influenced by the thickness of sludge. The Effective moisture diffusivity was calculated by using Fick’s second law. Thin layers of sludge formed by superheated steam drying having thicknesses of 2, 4, 6, and 10 mm had effective diffusion coefficient variations of 2.0641×10-9-8.8527×10-9, 4.3738×10-9-1.6626×10-8, 6.6082×10-9-2.46×10-8, and 1.1916×10-8-4.0806×10

  8. Visual study of propagation of self-sustained evaporation front within the thickness of a thermal liquid layer

    Science.gov (United States)

    Zhukov, V. E.; Moiseev, M. I.; Kuznetsov, D. V.

    2016-10-01

    In the range of low reduced pressures, the development of self-sustained evaporation front along the heat-releasing surface at non-stationary heat release is an important factor that determines possible transition to film boiling at heat fluxes, significantly lower than the critical heat fluxes at stationary heat release. This paper presents the experimental results on the scale of a leading part of the interface of self-sustained evaporation front at stepped heat release. The scale of the leading part of the interface of the evaporation front is compared with the thermal layer thickness, registered using the shadow method of visualization at high-speed video shooting with up to 25,000 frames per second. Experiments were carried out in Freon R21 under the conditions of free convection at relative pressures of 0.032 - 0.068. It is shown that self-sustained evaporation front spreads along the heated wall within the thickness of a liquid layer, superheated relative to the saturation temperature. Dependence of the front velocity on wall superheating relative to the saturation temperature does not change with significant subcooling to the temperature of liquid saturation in the volume.

  9. Neutron-gamma discrimination by pulse analysis with superheated drop detector

    CERN Document Server

    Das, Mala; Saha, S; Bhattacharya, S; Bhattacharjee, P

    2010-01-01

    Superheated drop detector (SDD) consisting of drops of superheated liquid of halocarbon is irradiated to neutrons and gamma-rays from 252Cf fission neutron source and 137Cs gamma source separately. The analysis of pulse height of the signals in the neutron and gamma-ray sensitive temperature provides strong information on the identification of neutron and gamma-ray induced events.

  10. Steady thermal convection in multiple liquid layers

    Science.gov (United States)

    Prakash, Ajay

    1993-03-01

    Convective flow in multiple liquid layers confined in a rectangular cavity is investigated using analytical, numerical, and experimental techniques. The cavity is subjected to differential heating, either parallel to or perpendicular to the interfaces between liquid layers. Thermal convection in the liquid layers results from buoyancy and from temperature induced changes in interfacial tension. Since the genesis of buoyancy is gravity, buoyancy effects are significantly reduced in a low-gravity environment. Definition of a space flight experiment aboard the upcoming IML-2 mission along with validation of fluid dynamical models with ground based experimentation are the objectives of this investigation. Flow in shallow cavities subjected to differential heating parallel to the interfaces is analytically investigated using the method of matched asymptotic expansions. Natural convection, without the influence of thermocapillary forces, is investigated in two and three layer systems. In low-gravity environments, thermocapillary convection with deformable interfaces is also studied. Ground based experiments to visualize the flow field are conducted. Particle streak line photography is used to visualize the flow. Particle displacement tracking is used to evaluate the velocity vector field, and holographic interferometry is used to visualize the temperature field. Numerical simulation is performed with the computer code FIDAP. Convection due to differential heating perpendicular to the interfaces is investigated using a linear stability analysis. Two and three layers of infinite horizontal extent are considered. Ground based experiments are conducted to visualize the temperature field in two and three layer systems confined in a box. Fluid dynamical models relying on mechanical coupling are experimentally validated for certain fluid combinations, while for other fluid combinations significant disparity is observed. An immobile interface is observed in the experiments

  11. Medium-Range Order Structure and Fragility of Superheated Melts of Amorphous CuHf Alloys

    Institute of Scientific and Technical Information of China (English)

    BIAN Xiu-Fang; SUN Bao-An; HU Li-Na

    2006-01-01

    @@ The structural factors of amorphous CuHf alloys at different temperatures are determined by using a high temperature x-ray diffractometer. It is found that not only the short-range order structure but also the medium-range order structure exists in amorphous CuHf alloys. The dynamic viscosities of CuHf alloy melts are measured by a torsional oscillation viscometer. The fragility of superheated melts of CuHf alloys is calculated based on the viscosity data. The experimental results show that the glass-forming ability of the CuHf alloys is closely related to the fragility of their superheated melt. The relationship between the medium-range order structures and the fragility of superheated melts has also been established in amorphous CuHf alloys. In contrast to the fragility of supercooled liquids, the fragility of superheated liquids promises a better approach to reflecting the dynamics of glass forming liquids.

  12. Study of acoustic emission due to vaporisation of superheated droplets at higher pressure

    Science.gov (United States)

    Sarkar, Rupa; Mondal, Prasanna Kumar; Chatterjee, Barun Kumar

    2017-08-01

    Bubble nucleation in superheated liquids can be controlled by adjusting the ambient pressure and temperature. At higher pressure the threshold energy for bubble nucleation increases, and we have observed that the amplitude of the acoustic emission during vaporisation of superheated droplet decreases with increase in pressure at any given temperature. Other acoustic parameters such as the primary harmonic frequency and the decay time constant of the acoustic signal also decrease with increase in pressure. This behavior is independent of the type of superheated liquid. The decrease in signal amplitude limits the detection of bubble nucleation at higher pressure. This effect is explained by the emission of shockwave generated during the supersonic growth of the microbubble in superheated liquids.

  13. Modeling interfacial liquid layers on environmental ices

    Directory of Open Access Journals (Sweden)

    M. H. Kuo

    2011-09-01

    Full Text Available Interfacial layers on ice significantly influence air-ice chemical interactions. In solute-containing aqueous systems, a liquid brine may form upon freezing due to the exclusion of impurities from the ice crystal lattice coupled with freezing point depression in the concentrated brine. The brine may be segregated to the air-ice interface where it creates a surface layer, in micropockets, or at grain boundaries or triple junctions.

    We present a model for brines and their associated liquid layers in environmental ice systems that is valid over a wide range of temperatures and solute concentrations. The model is derived from fundamental equlibrium thermodynamics and takes into account nonideal solution behavior in the brine, partitioning of the solute into the ice matrix, and equilibration between the brine and the gas phase for volatile solutes. We find that these phenomena are important to consider when modeling brines in environmental ices, especially at low temperatures. We demonstrate its application for environmentally important volatile and nonvolatile solutes including NaCl, HCl, and HNO3. The model is compared to existing models and experimental data from literature where available. We also identify environmentally relevant regimes where brine is not predicted to exist, but the QLL may significantly impact air-ice chemical interactions. This model can be used to improve the representation of air-ice chemical interactions in polar atmospheric chemistry models.

  14. Drop Impact on Superheated Surfaces

    NARCIS (Netherlands)

    Tran, A.T.; Staat, H.J.J.; Prosperetti, A.; Sun, C.; Lohse, D.

    2012-01-01

    At the impact of a liquid droplet on a smooth surface heated above the liquid’s boiling point, the droplet either immediately boils when it contacts the surface (“contact boiling”), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (“gentle film

  15. Drop impact on superheated surfaces

    CERN Document Server

    Tran, Tuan; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2011-01-01

    At impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (``contact boiling''), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (``gentle film boiling''), or both forms the Leidenfrost layer and ejects tiny droplets upward (``spraying film boiling''). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading $\\gamma$ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number $\\We$ ($\\gamma\\sim\\We^{2/5}$) -- regardless of surface temperature and of liquid properties -- which is much steeper than for the impact on non-heated (hydrophilic or hydrophobic) surfaces ($\\gamma\\sim\\We^{1/4}$). We also intereferometrically measure the vapor thickness under the droplet.

  16. Complex dynamics of evaporation-driven convection in liquid layers

    CERN Document Server

    Chauvet, F; Colinet, P

    2010-01-01

    The spontaneous convective patterns induced by evaporation of a pure liquid layer are studied experimentally. A volatile liquid layer placed in a cylindrical container is left free to evaporate into air at rest under ambient conditions. The liquid/gas interface of the evaporating liquid layer is visualized using an infrared (IR) camera. The phenomenology of the observed convective patterns is qualitatively analysed, showing in particular that the latter can be quite complex especially at moderate liquid thicknesses. Attention is also paid to the influence of the container diameter on the observed patterns sequence.

  17. Neutron - Alpha irradiation response of superheated emulsion detectors

    Science.gov (United States)

    Felizardo, M.; Morlat, T.; Girard, T. A.; Kling, A.; Fernandes, A. C.; Marques, J. G.; Carvalho, F.; Ramos, A. R.

    2017-08-01

    We report new experimental investigations of the response of single superheated emulsion detectors with small droplet (<30 μm radii) size distributions to both α- and neutron irradiations. Analysis of the results in terms of the underlying detector physics yields a toy model which reasonably reproduces the observations, and identifies the initial energy of the α in the liquid and distribution of droplet sizes as primarily responsible for the detector capacity to distinguish between nuclear recoil and α events.

  18. Drop impact on superheated surfaces.

    Science.gov (United States)

    Tran, Tuan; Staat, Hendrik J J; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2012-01-20

    At the impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surface ("contact boiling"), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back ("gentle film boiling"), or both forms the Leidenfrost layer and ejects tiny droplets upward ("spraying film boiling"). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading γ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number We (γ~We(2/5)), which is much steeper than for the impact on nonheated (hydrophilic or hydrophobic) surfaces (γ~We(1/4)). We also interferometrically measure the vapor thickness under the droplet.

  19. Theoretical modeling of orientational effects in liquid-crystal layers

    Science.gov (United States)

    Melnikova, E. A.

    2005-11-01

    In the work the approximate analytical relations describing the director distribution in depth of a plane-parallel layer of nematic liquid crystal are presented. The analytical expression determining the orientational effect of the periodic surface in a system "relief grating - liquid crystal" is derived. Its diffraction characteristics are studied theoretically. Relaxation kinetics of the director in a plane-parallel layer of nematic liquid crystal is considered taking account of the microscopic inertia moment.

  20. Regenerative superheated steam turbine cycles

    Science.gov (United States)

    Fuller, L. C.; Stovall, T. K.

    1980-01-01

    PRESTO computer program was developed to analyze performance of wide range of steam turbine cycles with special attention given to regenerative superheated steam turbine cycles. It can be used to model standard turbine cycles, including such features as process steam extraction, induction and feedwater heating by external sources, peaking, and high back pressure. Expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses are used to calculate cycle heat rate and generator output. Program provides power engineer with flexible aid for design and analysis of steam turbine systems.

  1. Superheated water chromatography--a green technology for the future.

    Science.gov (United States)

    Smith, Roger M

    2008-03-14

    Reversed phase liquid chromatography using superheated water as the mobile phase, at temperatures between 100 and 250 degrees C, offers a number of advantages for the analyst. It is an environmentally clean solvent, reducing solvent usage and disposal costs. It has advantages in detection, allowing UV spectra to be monitored down to short wavelengths, as well as a compatibility with universal flame ionisation detection and mass spectroscopy. By employing deuterium oxide as the eluent, solvent free NMR spectra can be measured. The development of newer more thermally stable stationary phases, including hybrid phases, have expanded the analytes that can be examined and these now range from alkylbenzenes, phenols, alkyl aryl ketones and a number of pharmaceuticals to carboxylic acids, amino acids, and carbohydrates. Very few compounds have been found to be unstable during the analysis. The separation methods can be directly coupled to superheated water extraction providing a totally solvent free system for sample extraction and analysis.

  2. Experimental investigation on coupling flows between liquid and liquid metal layers

    Science.gov (United States)

    Yano, Kanako; Tasaka, Yuji; Murai, Yuichi; Takeda, Yasushi; Yanagisawa, Takatoshi

    2008-11-01

    This study aims to clarify coupling of flows between liquid metal and other usual liquids, e.g. water or oil, in fluid dynamical systems. In past studies for two-layer Rayleigh-Bénard system where the immiscible two liquids are layered, two types of coupling were observed; these are called as ``mechanical coupling'' and ``thermal coupling.'' As a typical character of low Pr fluid, large-scale structure in the liquid metal layer has oscillating motion. In this study we investigate ``thermal coupling'' especially how the oscillation of cells in the liquid metal layer propagates to the upper liquid layer and vice versa by changing a ratio of the height of the layers and viscosity of the upper layer fluid. Visualization of the liquid metal motion was conducted by means of ultrasonic velocity profiling, and then the oscillating motion is expressed on the space-time velocity map. PIV measurement of the upper, transparent fluid layer shows the modulation of the convective motion due to the oscillation in the liquid metal layer. Point-wise measurement of temperature at several positions in the fluid layer represents the modulation quantitatively.

  3. Surface tension-driven convection patterns in two liquid layers

    CERN Document Server

    Juel, A; McCormick, W D; Swift, J B; Swinney, H L; Juel, Anne; Burgess, John M.; Swinney, Harry L.

    1999-01-01

    Two superposed liquid layers display a variety of convective phenomena that are inaccessible in the traditional system where the upper layer is a gas. We consider several pairs of immiscible liquids. Once the liquids have been selected, the applied temperature difference and the depths of the layers are the only independent control parameters. Using a perfluorinated hydrocarbon and silicone oil system, we have made the first experimental observation of convection with the top plate hotter than the lower plate. Since the system is stably stratified, this convective flow is solely due to thermocapillary forces. We also have found oscillatory convection at onset in an acetonitrile and n-hexane system heated from below.

  4. Comparative study of the surface layer density of liquid surfaces

    Science.gov (United States)

    Chacón, E.; Fernández, E. M.; Duque, D.; Delgado-Buscalioni, R.; Tarazona, P.

    2009-11-01

    Capillary wave fluctuations blur the inherent structure of liquid surfaces in computer simulations. The intrinsic sampling method subtracts capillary wave fluctuations and yields the intrinsic surface structure, leading to a generic picture of the liquid surface. The most relevant magnitude of the method is the surface layer density ns that may be consistently determined from different properties: the layering structure of the intrinsic density profiles, the turnover rate for surface layer particles, and the hydrodynamic damping rate of capillary waves. The good agreement among these procedures provides evidence for the physical consistency of the surface layering hypothesis, as an inherent physical property of the liquid surfaces. The dependence of the surface compactness, roughness, and exchange rate with temperature is analyzed for several molecular interaction models.

  5. Shear viscoelastic properties of liquids and their boundary layers.

    Science.gov (United States)

    Badmaev, Badma B; Dembelova, Tuyana S; Damdinov, Bair B

    2003-07-01

    An acoustical resonance method with piezoquartz vibrator was used in the experimental determination of shear elasticity modulus and a tangent of mechanical loss angle of studied liquids and their boundary layers. It has been shown that liquid has an earlier unknown low frequency (approx. 100 kHz) viscoelastic relaxation process. The experimental results of investigation of low frequency shear elasticity of different class of liquids and their solutions have been presented. An experimental research of shear properties in dependence on shear deformation rate has been carried out. The possibility of the discovery of anomalous high viscosity of liquids has also been considered.

  6. Study of low frequency acoustic signals from superheated droplet detector

    CERN Document Server

    Mondal, P K; Das, M; Bhattacharjee, P

    2013-01-01

    The bubble nucleation process in superheated droplet detector (SDD) is associated with the emission of an acoustic pulse that can be detected by an acoustic sensor. We have studied the neutron and gamma-ray induced nucleation events in a SDD with the active liquid R-12 (CCl2F2, b.p. -29.8oC) using a condenser microphone sensor. A comparative study in the low frequency region (~ 0-10kHz) for the neutron and gamma-ray induced nucleation is presented here. From the analysis of the waveforms we observe a significant difference between the neutron and gamma-ray induced acoustic events.

  7. Gravitational instability of thin gas layer between two thick liquid layers

    Science.gov (United States)

    Pimenova, A. V.; Goldobin, D. S.

    2016-12-01

    We consider the problem of gravitational instability (Rayleigh-Taylor instability) of a horizontal thin gas layer between two liquid half-spaces (or thick layers), where the light liquid overlies the heavy one. This study is motivated by the phenomenon of boiling at the surface of direct contact between two immiscible liquids, where the rate of the "break-away" of the vapor layer growing at the contact interface due to development of the Rayleigh-Taylor instability on the upper liquid-gas interface is of interest. The problem is solved analytically under the assumptions of inviscid liquids and viscous weightless vapor. These assumptions correspond well to the processes in real systems, e.g., they are relevant for the case of interfacial boiling in the system water- n-heptane. In order to verify the results, the limiting cases of infinitely thin and infinitely thick gas layers were considered, for which the results can be obviously deduced from the classical problem of the Rayleigh-Taylor instability. These limiting cases are completely identical to the well-studied cases of gravity waves at the liquidliquid and liquid-gas interfaces. When the horizontal extent of the system is long enough, the wavenumber of perturbations is not limited from below, and the system is always unstable. The wavelength of the most dangerous perturbations and the rate of their exponential growth are derived as a function of the layer thickness. The dependence of the exponential growth rate on the gas layer thickness is cubic.

  8. Liquid-like layers on ice in the environment: bridging the quasi-liquid and brine layer paradigms

    Directory of Open Access Journals (Sweden)

    M. H. Kuo

    2011-03-01

    Full Text Available Liquid-like layers on ice significantly influence atmospheric chemistry in polar regions. In the absence of impurities a nanoscale region of surface disorder known as the "quasi-liquid layer" (QLL may exist below the bulk melting point (down to ~−30 °C. Surface and bulk impurities are known to modulate the QLL thickness. In aqueous systems containing ionic solutes, a liquid brine layer (BL may form upon freezing due to the exclusion of impurities from the ice crystal lattice coupled with freezing point depression in the concentrated surface layer. Brine layers are conceptually distinct from the QLL, which can exist in the absence of impurities.

    We have developed a unified model for liquid-like layers in environmental ice systems that is valid over a wide range of temperatures and solute concentrations, spanning the QLL and BL regimes. The model consists of two coupled modules describing the thickness of the BL and the QLL. The BL module is derived from fundamental equlibrium thermodynamics, whereas the QLL formulation is derived semi-empirically based on statistical mechanical principles and previously published QLL thickness data. The resulting unified model has been tested against experimental data from literature and applied to several environmentally important systems, such as HCl(g-ice, HNO3(g-ice, and frozen sea ice. This model can be used to improve the representation of air-ice chemical interactions in polar atmospheric chemistry models.

  9. Thermocapillary convection in a liquid layer with local heating

    Energy Technology Data Exchange (ETDEWEB)

    Val' tsiferov, Yu.V.; Ryazantsev, Yu.S.; Shevtsova, V.M.

    1988-03-01

    The motion induced in a liquid by a heat pulse from an ultraviolet laser is mathematically described. The shape of the region occupied by the liquid and the initial position of the zone heated and colored by the radiation is shown. The velocity and temperature distributions on the surface and in the body of the liquid were determined numerically. The theoretical results were compared with the experimental data of Al'vares-Suares and Ryazantsev. Features of the behavior of the velocity and temperature at the liquid surface are closely associated with the nature of the motion in the body of the liquid caused by the surface thermocapillary forces. The development of vortex motion and heat propagation in a layer is illustrated.

  10. Nanostructure of the Ionic Liquid-Graphite Stern Layer.

    Science.gov (United States)

    Elbourne, Aaron; McDonald, Samila; Voïchovsky, Kislon; Endres, Frank; Warr, Gregory G; Atkin, Rob

    2015-07-28

    Ionic liquids (ILs) are attractive solvents for devices such as lithium ion batteries and capacitors, but their uptake is limited, partially because their Stern layer nanostructure is poorly understood compared to molecular solvents. Here, in situ amplitude-modulated atomic force microscopy has been used to reveal the Stern layer nanostructure of the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIm TFSI)-HOPG (highly ordered pyrolytic graphite) interface with molecular resolution. The effect of applied surface potential and added 0.1 wt/wt % Li TFSI or EMIm Cl on ion arrangements is probed between ±1 V. For pure EMIm TFSI at open-circuit potential, well-defined rows are present on the surface formed by an anion-cation-cation-anion (A-C-C-A) unit cell adsorbed with like ions adjacent. As the surface potential is changed, the relative concentrations of cations and anions in the Stern layer respond, and markedly different lateral ion arrangements ensue. The changes in Stern layer structure at positive and negative potentials are not symmetrical due to the different surface affinities and packing constraints of cations and anions. For potentials outside ±0.4 V, images are featureless because the compositional variation within the layer is too small for the AFM tip to detect. This suggests that the Stern layer is highly enriched in either cations or anions (depending on the potential) oriented upright to the surface plane. When Li(+) or Cl(-) is present, some Stern layer ionic liquid cations or anions (respectively) are displaced, producing starkly different structures. The Stern layer structures elucidated here significantly enhance our understanding of the ionic liquid electrical double layer.

  11. High Reynolds number liquid layer flow with flexible walls

    Indian Academy of Sciences (India)

    J S B Gajjar

    2015-05-01

    The stability of liquid layer flow over an inclined flexible wall is studied using asymptotic methods based on the assumption that the Reynolds number is large. The flexible wall behaviour is described by a spring-plate model, and parameters chosen so that the wall flexibility affects the governing boundary layer problem. For the case of a rigid wall, the problem reverts to one studied by Gajjar. Asymptotic analysis of the governing equations leads to the triple-deck equations governing the interaction between the wall layer and the free-surface. The linearised and other solution properties of these set of equations are discussed.

  12. Research progress of the Superheated Steam Drying Technology

    OpenAIRE

    Shi, Yongchun; Li, Jie; Li, Xuanyou; Zhao, Gaiju; Wu, Maogang

    2012-01-01

    The superheated steam drying technology has lots of advantages such as safe, energy-saving, pollution-free and so on, so it causes more and more extensive concern. The superheated steam drying technology is introduced and its merits and faults are analyzed. The theoretical research progress of the superheated steam drying is summarized and the recent application of the materials including the food, wood, paper, sludge and lignite is stated. In brief, the superheated steam drying technol...

  13. Monodomain Blue Phase Liquid Crystal Layers for Phase Modulation

    Science.gov (United States)

    Oton, E.; Netter, E.; Nakano, T.; D.-Katayama, Y.; Inoue, F.

    2017-03-01

    Liquid crystal “Blue Phases” (BP) have evolved, in the last years, from a scientific curiosity to emerging materials for new photonic and display applications. They possess attractive features over standard nematic liquid crystals, like submillisecond switching times and polarization- independent optical response. However, BPs still present a number of technical issues that prevent their use in practical applications: their phases are only found in limited temperature ranges, thus requiring stabilization of the layers; stabilized BP layers are inhomogeneous and not uniformly oriented, which worsen the optical performance of the devices. It would be essential for practical uses to obtain perfectly aligned and oriented monodomain BP layers, where the alignment and orientation of the cubic lattice are organized in a single 3D structure. In this work we have obtained virtually perfect monodomain BP layers and used them in devices for polarization independent phase modulation. We demonstrate that, under applied voltage, well aligned and oriented layers generate smoother and higher values of the phase shift than inhomogeneous layers, while preserving polarization independency. All BP devices were successfully stabilized in BPI phase, maintaining the layer monodomain homogeneity at room temperature, covering the entire area of the devices with a unique BP phase.

  14. Monodomain Blue Phase Liquid Crystal Layers for Phase Modulation

    Science.gov (United States)

    Oton, E.; Netter, E.; Nakano, T.; D.-Katayama, Y.; Inoue, F.

    2017-01-01

    Liquid crystal “Blue Phases” (BP) have evolved, in the last years, from a scientific curiosity to emerging materials for new photonic and display applications. They possess attractive features over standard nematic liquid crystals, like submillisecond switching times and polarization- independent optical response. However, BPs still present a number of technical issues that prevent their use in practical applications: their phases are only found in limited temperature ranges, thus requiring stabilization of the layers; stabilized BP layers are inhomogeneous and not uniformly oriented, which worsen the optical performance of the devices. It would be essential for practical uses to obtain perfectly aligned and oriented monodomain BP layers, where the alignment and orientation of the cubic lattice are organized in a single 3D structure. In this work we have obtained virtually perfect monodomain BP layers and used them in devices for polarization independent phase modulation. We demonstrate that, under applied voltage, well aligned and oriented layers generate smoother and higher values of the phase shift than inhomogeneous layers, while preserving polarization independency. All BP devices were successfully stabilized in BPI phase, maintaining the layer monodomain homogeneity at room temperature, covering the entire area of the devices with a unique BP phase. PMID:28281691

  15. Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation

    Science.gov (United States)

    Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

    2016-03-01

    Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors.

  16. Electrostatic Debye layer formed at a plasma-liquid interface

    Science.gov (United States)

    Rumbach, Paul; Clarke, Jean Pierre; Go, David B.

    2017-05-01

    We construct an analytic model for the electrostatic Debye layer formed at a plasma-liquid interface by combining the Gouy-Chapman theory for the liquid with a simple parabolic band model for the plasma sheath. The model predicts a nonlinear scaling between the plasma current density and the solution ionic strength, and we confirmed this behavior with measurements using a liquid-anode plasma. Plots of the measured current density as a function of ionic strength collapse the data and curve fits yield a plasma electron density of ˜1019m-3 and an electric field of ˜104V /m on the liquid side of the interface. Because our theory is based firmly on fundamental physics, we believe it can be widely applied to many emerging technologies involving the interaction of low-temperature, nonequilibrium plasma with aqueous media, including plasma medicine and various plasma chemical synthesis techniques.

  17. Electric double layer at the interface of ionic liquid-dielectric liquid under electric field.

    Science.gov (United States)

    Lee, D W; Im, D J; Kang, I S

    2013-02-12

    The structure of the electric double layer (EDL) is analyzed in order to understand the electromechanical behavior of the interface of ionic liquid-dielectric liquid. The modified Poisson-Boltzmann equation proposed by Bazant et al. is solved to see the crowding and the overscreening effects that are the characteristics of an ionic liquid (Bazant, M. Z.; Storey, B. D.; Kornyshev, A. A. Double layer in ionic liquids: Overscreening versus crowding. Phys. Rev. Lett. 2011, 106, 046102.). From the simple one-dimensional (1-D) analysis, it is found that the changes of the composition and the material properties in the EDL are negligible except under some extreme conditions such as strong electric field over O(10(8)) V/m. From the electromechanical view points, an ionic liquid behaves like a pure conductor at the interface with a dielectric liquid. Based on these findings, three specific application problems are considered. In the first, a new method is suggested for measuring the interfacial tension of an ionic liquid-dielectric liquid system. The deformation of a charged ionic liquid droplet translating between two electrodes is used for this measurement. The second is for the Taylor cone problem, which includes an extreme electric field condition near the tip. The size of the critical region, where the EDL effect should be considered, is estimated by using the 1-D analysis result. Numerical computation is also performed to see the profiles of electric potential and the electric stress along the interface of the Taylor cone. Lastly, the electrowetting problem of the ionic liquid is considered. The discrepancies in the results of previous workers are interpreted by using the results of the present work. It is shown that all the results might be consistent if the leaking of the dielectric layer and/or the adsorption of ions is considered.

  18. Superheated Droplet Detector Response for Temperature

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Superheated droplet detector has the following advantages: Used repeatedly, recording the cumulative dose, using both indoors and outdoors, compacting; relatively low cost, direct reading of the bubbles using the naked eye, and working in gamma-neutron mixed-field well

  19. Standardisation of superheated drop and bubble detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F.; D' Errico, F

    2002-07-01

    This study presents an analysis of the commercially available superheated drop detectors and bubble detectors, performed in substantial accordance with the guidelines developed by the International Organisation for Standardization (ISO). The analysis was performed in terms of linearity, reproducibility, ageing, minimum detection thresholds, energy and angular dependence of the response and the influence of various climatic conditions. (author)

  20. LET dependence of bubbles evaporation pulses in superheated emulsion detectors

    Science.gov (United States)

    Di Fulvio, Angela; Huang, Jean; Staib, Lawrence; d'Errico, Francesco

    2015-06-01

    Superheated emulsion detectors are suspensions of metastable liquid droplets in a compliant inert medium. Upon interaction with ionizing radiation, the droplets evaporate, generating visible bubbles. Bubble expansion associated with the boiling of the droplets is accompanied by pressure pulses in both the sonic and ultrasonic frequency range. In this work, we analyzed the signal generated by bubble evaporation in the frequency and time domain. We used octafluoropropane (R-218) based emulsions, sensitive to both photons and neutrons. The frequency content of the detected pulses appears to extend well into the hundreds of kHz, beyond the range used in commercial devices to count bubbles as they are formed (typically 1-10 kHz). Kilohertz components characterize the early part of the waveforms, potentially containing information about the energetics of the explosive bubble initial growth phase. The power spectral density of the acoustic signal produced by neutron-induced evaporation shows a characteristic frequency pattern in the 200-400 kHz range, which is not observed when bubbles evaporate upon gamma ray-induced irradiation. For practical applications, detection of ultrasonic pulses associated with the boiling of the superheated drops can be exploited as a fast readout method, negligibly affected by mechanical ambient noise.

  1. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    Science.gov (United States)

    Annenkova, E. A.; Kreider, W.; Sapozhnikov, O. A.

    2015-10-01

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  2. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    Energy Technology Data Exchange (ETDEWEB)

    Annenkova, E. A., E-mail: a-a-annenkova@yandex.ru [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Kreider, W. [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States); Sapozhnikov, O. A. [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States)

    2015-10-28

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  3. Sloshing instability and electrolyte layer rupture in liquid metal batteries

    Science.gov (United States)

    Weber, Norbert; Beckstein, Pascal; Herreman, Wietze; Horstmann, Gerrit Maik; Nore, Caroline; Stefani, Frank; Weier, Tom

    2017-05-01

    Liquid metal batteries (LMBs) are discussed today as a cheap grid scale energy storage, as required for the deployment of fluctuating renewable energies. Built as stable density stratification of two liquid metals separated by a thin molten salt layer, LMBs are susceptible to short-circuit by fluid flows. Using direct numerical simulation, we study a sloshing long wave interface instability in cylindrical cells, which is already known from aluminium reduction cells. After characterising the instability mechanism, we investigate the influence of cell current, layer thickness, density, viscosity, conductivity and magnetic background field. Finally we study the shape of the interface and give a dimensionless parameter for the onset of sloshing as well as for the short-circuit.

  4. Dynamics of liquid solidification thermal resistance of contact layer

    CERN Document Server

    Lipnicki, Zygmunt

    2017-01-01

    This monograph comprehensively describes phenomena of heat flow during phase change as well as the dynamics of liquid solidification, i.e. the development of a solidified layer. The book provides the reader with basic knowledge for practical designs, as well as with equations which describe processes of energy transformation. The target audience primarily comprises researchers and experts in the field of heat flow, but the book may also be beneficial for both practicing engineers and graduate students.

  5. The collective motion of nematodes in a thin liquid layer

    CERN Document Server

    Gart, Sean; Jung, Sunghwan

    2010-01-01

    Many organisms live in confined fluidic environments such as the thin liquid layers on the skin of host organisms or in partially- saturated soil. We investigate the collective behaviour of nematodes in a thin liquid layer, which was first observed by Gray and Lissmann, [J. Exp. Biol. 41, 135 (1964)]. We show experimentally that nematodes confined by a thin liquid film come into contact and only separate again after some intervention. We attribute this collective motion to an attractive force between them arising from the surface tension of the layer and show that for nearby nematodes this force is typically stronger than the force that may be exerted by the nematodes' muscles. We believe this to be the first demonstration of the "Cheerios effect" acting on a living organism. However, we find that being grouped together does not significantly alter the body stroke and kinematic performance of the nematode: there are no statistically significant changes of the Strouhal number and the ratio of amplitude to wave...

  6. Acoustic waves in compressible planar layered smectic liquid crystals

    Science.gov (United States)

    Walker, A. J.; Stewart, I. W.

    2010-08-01

    A dynamic theory for compressible smectic C (SmC) liquid crystals is postulated following previous work by Leslie et al (1991 Mol. Cryst. Liq. Cryst. 198 443-54), Nakagawa (1996 J. Phys. Soc. Japan 65 100-6 2004 J. Non-Newtonian Fluid Mech. 119 123-9) and de Gennes and Prost (1993 The Physics of Liquid Crystals 2nd edn (Oxford: Oxford University Press)). This theory is then implemented with a constructed bulk elastic energy and asymmetric stress tensor to describe a system of planar layered SmC liquid crystals undergoing various modes of undulation. We show that previous work on smectic A (SmA) liquid crystals by de Gennes and Prost (1993 The Physics of Liquid Crystals 2nd edn (Oxford: Oxford University Press)) can be expanded for SmC and consolidated. Novel and confirming estimates for SmC material parameter values are produced by considering the dependence of the system on these parameters.

  7. Effect of Melt Superheating Treatment on Directional Solidification Interface Morphology of Multi-component Alloy

    Institute of Scientific and Technical Information of China (English)

    Changshuai Wang; Jun Zhang; Lin Liu; Hengzhi Fu

    2011-01-01

    The influence of melt superheating treatment on the solid/liquid (S/L) interface morphology of directionally solidified Ni-based superalloy DZ125 is investigated to elucidate the relationship between melt characteristic and S/L interface stability. The results indicate that the interface morphology is not only related to the withdrawal velocity (R) but also to the melt superheating temperature (Ts) when the thermal gradient of solidification interface remains constant for different Ts with appropriate superheating treatment regulation. The interface morphology changes from cell to plane at R of 1.1 μm/s when Ts increases from 1500°C to 1650°C, and maintains plane with further elevated Ts of 1750°C. However, the interface morphology changes from coarse dendrite to cell and then to cellular dendrite at R of 2.25 μm/s when Ts increases from 1500°C to 1650°C and then to 1750°C. It is proved that the solidification onset temperature and the solidification interval undergo the nonlinear variation when Ts increases from 1500°C to 1680°C, and the turning point is 1650°C at which the solidification onset temperature and the solidification interval are all minimum. This indicates that the melt superheating treatment enhances the solidification interface stability and has important effect on the solidification characteristics.

  8. Rewetting of a low superheated rod with saturated water

    Energy Technology Data Exchange (ETDEWEB)

    Portillo, O.; Reyes, R.; Wayner, P.C. Jr.

    1999-07-01

    The study of the rewetting of a superheated surface has application in several technological fields. It is related to the control mechanism for loss of coolant accident (LOCA) in nuclear reactors. An adsorption model as the precursory mechanism for rewetting of a superheated surface is extended from its application to non-polar liquids to a polar fluid, and modeling calculations are compared with experimental data found in the literature. The adsorption model is based on interfacial forces acting at the tip of the rewetting front, the three-phase region. In this region, solid, liquid and vapor interfaces generate a contact angle that depends on the degree of superheat and describes the velocity of rewetting. The contact angle is a function of interfacial forces calculated through the disjoining pressure of the adsorbed film precursory of the rewetting. The influences of van der Waals and electrostatic intermolecular forces in the film thickness are analyzed. The authors find that the order of magnitude of the film thickness in the controlling region is of a few angstroms: thus, only van der Waals intermolecular forces define the interactions. For the prediction of the velocity of rewetting the temperature profile along the rod's surface is required and a one-dimensional and a two-dimensional heat conduction balances are solved. The thermophysical properties in the adsorption model are predicted by ASPEN PLUS data bank and from ASME steam tables. Variations of the predicted values have a strong influence on the results. The surface boundary condition on the rod contains an evaporative heat transfer coefficient that is calculated from the fitted experimental rewetting velocities and the two-dimensional temperature field in the rod. Using this calculation scheme the values of the evaporative heat transfer coefficient are obtained in the normal range of values. Therefore the adsorption model gives results that are consistent with experimental observations.

  9. A superheated Bose-condensed gas

    OpenAIRE

    Gaunt, Alexander L.; Fletcher, Richard J.; Robert P. Smith; Hadzibabic, Zoran

    2012-01-01

    Our understanding of various states of matter usually relies on the assumption of thermodynamic equilibrium. However, the transitions between different phases of matter can be strongly affected by non-equilibrium phenomena. Here we demonstrate and explain an example of non-equilibrium stalling of a continuous, second-order phase transition. We create a superheated atomic Bose gas, in which a Bose-Einstein condensate (BEC) persists above the equilibrium critical temperature, $T_c$, if its coup...

  10. Liquid Exfoliation of Layered Transition Metal Dichalcogenides for Biological Applications.

    Science.gov (United States)

    Nguyen, Emily P; Daeneke, Torben; Zhuiykov, Serge; Kalantar-Zadeh, Kourosh

    2016-06-02

    Known to possess distinctive properties that differ greatly from their bulk form, layered two-dimensional materials have been extensively studied and incorporated into many versatile applications ranging from optoelectronics to sensors. For biomedical research, two-dimensional transition metal dichalcogenides (2D TMDs) have garnered much interest as they have been shown to exhibit relatively low toxicity, high stability in aqueous environments, and the ability to adhere to biological materials such as proteins. These materials are promising candidates, demonstrating potential applications in biosensing, cell imaging, diagnostics, and therapeutics. Preparation and exfoliation of 2D TMDs play an important part in these various applications as their properties are heavily dependent on the number of layers and lateral size. Described in this article are protocols for the liquid exfoliation of 2D TMDs from their bulk materials. Additional protocols are also provided for functionalizing or modifying the surface of the exfoliated 2D TMDs. © 2016 by John Wiley & Sons, Inc.

  11. A Study on the Violent Interactions of an Immiscible Drop impacting on a Superheated Pool

    KAUST Repository

    Alchalabi, Mohamad

    2014-05-01

    ABSTRACT A Study on the Violent Interactions of an Immiscible Drop Impacting on a Superheated Pool Mohamad Alchalabi The interactions between two immiscible liquids of different temperatures can be violent to the extent of causing harm to individuals, or damage to equipment, especially when used in the industry. Only a few studies investigated these interactions but they could not produce the violent interactions often reported by the industry, and therefore their results did not help much to develop clear understanding of the dynamics of these interactions. In this work, a high speed imaging system operated at 100,000 frames per second was utilized to record the events and phenomena taking place upon the impact of Perfluorohexane droplet at room temperature onto a hot soybean oil pool at temperatures as high as 300 ºC. The impact velocity was varied by varying the height of the droplet before it pinches off under its own weight. The recorded events identified the occurrence of vortex ring vapor explosions, weak and strong nucleate boiling, and film boiling. An impact velocity vs. oil temperature diagram identifying the regions in which each of these phenomena takes place was generated, and the dynamics driving their occurrences were explored. The vortex ring vapor explosions were found to become less violent as the impact velocity was increased, which was attributed to the existence of a smaller amount of liquid Perfluorohexane within the rings at high speed impacts, which does evaporate but does not expand violently. Weak nucleate boiling occurred at very high impact velocities relatively. As the temperature is increased, however, they start 5 turning into strong nucleate boiling. The strong nucleate boiling usually starts right upon impact, and when the temperature of the oil at one impact velocity is increased, it starts turning into film boiling, in which the liquid Perfluorohexane is covered by a vapor layer of its own vapor.

  12. Small Molecule-Assisted Exfoliation of Layered Zirconium Phosphate Nanoplatelets by Ionic Liquids

    Science.gov (United States)

    Xia, Fangqing; Yong, Huaisong; Han, Xiao; Sun, Dazhi

    2016-07-01

    Exfoliation of layered inorganic nanomaterials into single-layered sheets has been widely interested in materials chemistry and composite fabrication. Here, we report the exfoliation of layered zirconium phosphate nanoplatelets by using small molecule intercalating agents in ionic liquids, which opens a new platform for fabricating single-layered inorganic materials from synthetic layered compounds.

  13. Wetted Foam Liquid DT Layer ICF Experiments at the NIF

    Science.gov (United States)

    Olson, R. E.; Leeper, R. J.; Peterson, R. R.; Yi, S. A.; Zylstra, A. B.; Kline, J. L.; Bradley, P. A.; Yin, L.; Wilson, D. C.; Haines, B. M.; Batha, S. H.

    2016-10-01

    A key physics issue in indirect-drive ICF relates to the understanding of the limitations on hot spot convergence ratio (CR), principally set by the hohlraum drive symmetry, the capsule mounting hardware (the ``tent''), and the capsule fill tube. An additional key physics issue relates to the complex process by which a hot spot must be dynamically formed from the inner ice surface in a DT ice-layer implosion. These physics issues have helped to motivate the development of a new liquid DT layer wetted foam platform at the NIF that provides an ability to form the hot spot from DT vapor and experimentally study and understand hot spot formation at a variety of CR's in the range of 12layered implosions will have understandable performance - providing a sound basis from which to determine the requirements for ICF ignition. This work was performed under the auspices of the U. S. DOE by LANL under contract DE-AC52-06NA25396.

  14. Status of Superheated Spray and Post Combustor Particulate Modeling for NCC

    Science.gov (United States)

    Liu, Nan-Suey; Raju, Suri; Wey, Thomas

    2007-01-01

    At supersonic cruise conditions, high fuel temperatures, coupled with low pressures in the combustor, create potential for superheated fuel injection leading to shorter fuel jet break-up time and reduced spray penetration. Another issue particularly important to the supersonic cruise is the aircraft emissions contributing to the climate change in the atmosphere. Needless to say, aircraft emissions in general also contribute to the air pollution in the neighborhood of airports. The objectives of the present efforts are to establish baseline for prediction methods and experimental data for (a) liquid fuel atomization and vaporization at superheated conditions and (b) particle sampling systems and laboratory or engine testing environments, as well as to document current capabilities and identify gaps for future research.

  15. Convection Study by PIV Method Within Horizontal Liquid Layer Evaporating Into Inert Gas Flow

    Directory of Open Access Journals (Sweden)

    Kreta Aleksei

    2016-01-01

    Full Text Available The paper is devoted to the experimental study of convection in a horizontal evaporating liquid layer (ethanol of limited size under the action of gas flow (air. The two-dimensional velocity field in the liquid layer is obtained using the PIV method. The existence of a vortex convective flow within a liquid layer directed towards the gas flow has been revealed.

  16. Surface-tension-driven convection in pure liquid layers evaporating into ambient air: influence of liquid volatility

    Science.gov (United States)

    Chauvet, Fabien; Dehaeck, Sam; Colinet, Pierre

    2011-11-01

    The spontaneous surface-tension-driven convective patterns induced by evaporation of a pure liquid layer are studied experimentally. A volatile liquid layer placed in a cylindrical container is left free to evaporate into air at rest under ambient conditions. The thermal dynamics of the evaporating liquid layer is visualized using an infrared camera. Evaporation rate and liquid thickness are measured by weighting. We focus on the transition between the convective state and the conductive state appearing at a certain instant during the drying of the liquid layer. The critical Marangoni number Mac associated to this transition is estimated from evaporation rate and layer thickness measurements at this instant. The effect of the evaporation rate on Mac and kc (the critical wavenumber) has been investigated by changing the container height and, separately, the effect of the liquid volatility has been studied by using different liquids. Interestingly, it appears that Mac does not depend on the evaporation rate while it depends strongly on the liquid volatility. Given the typical uncertainties associated with liquid properties, a quite reasonable agreement is found with a ``one-sided'' linear stability analysis of this problem. Supported by ESA & BELSPO, by the EU, by ULB, and by FRS - FNRS.

  17. Ultrasonic system for continuous washing of textiles in liquid layers.

    Science.gov (United States)

    Gallego-Juarez, Juan A; Riera, Enrique; Acosta, Victor; Rodríguez, Germán; Blanco, Alfonso

    2010-01-01

    The use of ultrasonic energy for washing of textiles has been tried several times without achieving practical development. In fact, the softness of the fibres makes the cavitation to produce small erosion effect and the reticulate structure of the fabric favours the formation of air bubble layers which obstruct wave penetration. In addition, a high proportion of water with respect to the wash load and a certain water degassing is required to assure efficiency and homogeneity in the wash performance. Such requirements have hindered the commercial development of the ultrasonic washing machines for domestic purposes. For specific industrial applications, a great part of these limitations may be overcome. This article deals with a new process in which the fabric is exposed to the ultrasonic field in a flat format. Such process has been implemented at laboratory and at semi-industrial stage by using specially designed power ultrasonic transducers with rectangular plate radiators. The cleaning effect is produced by the intense cavitation field generated by the plate radiator within a thin layer of liquid where the fabric is introduced. The homogeneity of such effect is achieved by the successive exposure of all the fabric areas to the intense acoustic field. In this paper the structure and performance of the developed system are shown.

  18. Graphical procedure for comparing thermal death of Bacillus stearothermophilus spores in saturated and superheated steam.

    Science.gov (United States)

    SHULL, J J; ERNST, R R

    1962-09-01

    The thermal death curve of dried spores of Bacillus stearothermophilus in saturated steam was characterized by three phases: (i) a sharp initial rise in viable count; (ii) a low rate of death which gradually increased; and (iii) logarithmic death at maximal rate. The first phase was a reflection of inadequate heat activation of the spore population. The second and third phases represented the characteristic thermal death curve of the spores in saturated steam. A jacketed steam sterilizer, equipped with a system for initial evacuation of the chamber, was examined for superheat during normal operation. Measurements of spore inactivation and temperature revealed superheat in surface layers of fabrics being processed in steam at 121 C. The high temperature of the fabric surfaces was attributed to absorption of excess heat energy from superheated steam. The superheated steam was produced at the beginning of the normal sterilizing cycle by transfer of heat from the steam-heated jacket to saturated steam entering the vessel.

  19. The Study of a Liquid Droplet Falling Through Two Immiscible Layers of Liquids

    Science.gov (United States)

    Mesa, Bianca

    2013-11-01

    In an exploratory experiment, we noticed the unusual behaviors of liquid droplets falling through layers of oil and water. A rectangular container was filled with an aqueous solution and a layer of oil. A dropper was used to control the size of the droplet. Water was mixed with Bromothymol Blue dye, a chemical indicator, to visualize the flow processes. Surface tension and the buoyancy of the oil layer between the liquid droplet and the water below caused the liquid droplet to be stopped at the interface. Over time, the support weakened and the droplet would fall quickly through the water. The first of two cases was a salt water solution with NaOH, and the second consisted of balsamic vinegar and NaOH. Once the salt water droplet touched the aqueous solution, it collapsed, sank and spread rapidly at the interface. The sinking motion dragged the spreading fluid back to its center and then down. For the second case, a trace amount of the droplet spread rapidly at the interface while the main portion of the droplet sank and then spontaneously exploded. The difference in behavior is mainly due to the surface tension of the droplet in water. The underlying mechanisms of the droplet's flow instability are from the effects of diffusion weakening the surface tension. Bianca Mesa is an undergraduate student in the Ocean and Mechanical Engineering Department at Florida Atlantic University. She is pursuing a B.S. degree in Ocean Engineering. In addition to her academic interests, she is also an avid sailor.

  20. Proteins at fluid interfaces: adsorption layers and thin liquid films.

    Science.gov (United States)

    Yampolskaya, Galina; Platikanov, Dimo

    2006-12-21

    A review in which many original published results of the authors as well as many other papers are discussed. The structure and some properties of the globular proteins are shortly presented, special accent being put on the alpha-chymotrypsin (alpha-ChT), lysozyme (LZ), human serum albumin (HSA), and bovine serum albumin (BSA) which have been used in the experiments with thin liquid films. The behaviour of protein adsorption layers (PAL) is extensively discussed. The dynamics of PAL formation, including the kinetics of adsorption as well as the time evolution of the surface tension of protein aqueous solutions, are considered. A considerable place is devoted to the surface tension and adsorption isotherms of the globular protein solutions, the simulation of PAL by interacting hard spheres, the experimental surface tension isotherms of the above mentioned proteins, and the interfacial tension isotherms for the protein aqueous solution/oil interface. The rheological properties of PAL at fluid interfaces are shortly reviewed. After a brief information about the experimental methods for investigation of protein thin liquid (foam or emulsion) films, the properties of the protein black foam films are extensively discussed: the conditions for their formation, the influence of the electrolytes and pH on the film type and stability, the thermodynamic properties of the black foam films, the contact angles film/bulk and their dynamic hysteresis. The next center of attention concerns some properties of the protein emulsion films: the conditions for formation of emulsion black films, the formation and development of a dimpling in microscopic, circular films. The protein-phospholipid mixed foam films are also briefly considered.

  1. Detection of bubble nucleation event in superheated drop detector by the pressure sensor

    Indian Academy of Sciences (India)

    MALA DAS; NILANJAN BISWAS

    2017-01-01

    Superheated drop detector consisting of drops of superheated liquid suspended in polymer or gel matrix is of great demand, mainly because of its insensitivity to β-particles and γ -rays and also because of the low cost. The bubble nucleation event is detected by measuring the acoustic shock wave released duringthe nucleation process. The present work demonstrates the detection of bubble nucleation events by using the pressure sensor. The associated circuits for the measurement are described in this article. The detection of events is verified by measuring the events with the acoustic sensor. The measurement was done using drops of various sizes to study the effect of the size of the drop on the pressure recovery time. Probability of detection of events has increased for larger size of the superheated drops and lesser volume of air in contact with the gel matrix. The exponential decay fitting to the pressure sensor signals shows the dead time for pressure recovery of such a drop detector to be a few microseconds.

  2. Detection of bubble nucleation event in superheated drop detector by the pressure sensor

    Science.gov (United States)

    Das, Mala; Biswas, Nilanjan

    2017-01-01

    Superheated drop detector consisting of drops of superheated liquid suspended in polymer or gel matrix is of great demand, mainly because of its insensitivity to ß-particles and ?-rays and also because of the low cost. The bubble nucleation event is detected by measuring the acoustic shock wave released during the nucleation process. The present work demonstrates the detection of bubble nucleation events by using the pressure sensor. The associated circuits for the measurement are described in this article. The detection of events is verified by measuring the events with the acoustic sensor. The measurement was done using drops of various sizes to study the effect of the size of the drop on the pressure recovery time. Probability of detection of events has increased for larger size of the superheated drops and lesser volume of air in contact with the gel matrix. The exponential decay fitting to the pressure sensor signals shows the dead time for pressure recovery of such a drop detector to be a few microseconds.

  3. Thermoeconomic optimization of subcooled and superheated vapor compression refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Selbas, Resat; Kizilkan, OEnder; Sencan, Arzu [Technical Education Faculty, Department of Mechanical Education, Sueleyman Demirel University, Isparta 32260 (Turkey)

    2006-09-15

    An exergy-based thermoeconomic optimization application is applied to a subcooled and superheated vapor compression refrigeration system. The advantage of using the exergy method of thermoeconomic optimization is that various elements of the system - i.e., condenser, evaporator, subcooling and superheating heat exchangers - can be optimized on their own. The application consists of determining the optimum heat exchanger areas with the corresponding optimum subcooling and superheating temperatures. A cost function is specified for the optimum conditions. All calculations are made for three refrigerants: R22, R134a, and R407c. Thermodynamic properties of refrigerants are formulated using the Artificial Neural Network methodology. (author)

  4. Superheating of ice crystals in antifreeze protein solutions

    OpenAIRE

    Celik, Yeliz; Graham, Laurie A.; Mok, Yee-Foong; Bar, Maya; Davies, Peter L.; Braslavsky, Ido

    2010-01-01

    It has been argued that for antifreeze proteins (AFPs) to stop ice crystal growth, they must irreversibly bind to the ice surface. Surface-adsorbed AFPs should also prevent ice from melting, but to date this has been demonstrated only in a qualitative manner. Here we present the first quantitative measurements of superheating of ice in AFP solutions. Superheated ice crystals were stable for hours above their equilibrium melting point, and the maximum superheating obtained was 0.44 °C. When me...

  5. Advances in superheated drop (bubble) detector techniques

    Energy Technology Data Exchange (ETDEWEB)

    d`Errico, F. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari; Alberts, W.G.; Matzke, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    1997-09-01

    State-of-the-art neutron dosemeters based on superheated drop (bubble) detectors are described. These are either active systems for area monitoring, which rely on the acoustical recording of drop vaporisations, or passive pen size ones for personal dosimetry, based on optical bubble counting. The technological solutions developed for the construction of robust devices for health physics applications are described with special emphasis on methods adopted to reduce mechanical shock and temperature sensitivity of the detectors. Finally, a review is given of some current research activities. In particular, a new approach to neutron spectrometry is presented which relies on the thermal effects for the definition of the response matrix of the system. (author).

  6. Thermographic investigation of surface temperature of the evaporating liquid layer under the action of gas flow

    Directory of Open Access Journals (Sweden)

    Kreta Aleksei

    2017-01-01

    Full Text Available An experimental study of the temperature field on the surface of horizontal liquid layer (Ethanol evaporating into gas flow (Air has been performed. Temperature gradient of the gas-liquid interface has been measured with the help of Titanium 570M IR camera. Shear stresses on gas-liquid interface induced by thermocapillary effect and inert gas flow have been defined.

  7. Ordering layers of [bmim][PF6] ionic liquid on graphite surfaces: molecular dynamics simulation.

    Science.gov (United States)

    Maolin, Sha; Fuchun, Zhang; Guozhong, Wu; Haiping, Fang; Chunlei, Wang; Shimou, Chen; Yi, Zhang; Jun, Hu

    2008-04-01

    Microscopic structures of room temperature ionic liquid (IL) [bmim][PF6] on hydrophobic graphite surfaces have been studied in detail by molecular dynamics simulation. It is clearly shown that both the mass and electron densities of the surface adsorbed ionic liquid are oscillatory, and the first peak adjacent to the graphite surface is considerably higher than others, corresponding to a solidlike IL bottom layer of 6 angstroms thick. Three IL layers are indicated between the graphite surface and the inner bulk IL liquid. The individually simulated properties of single-, double-, and triple-IL layers on the graphite surface are very similar to those of the layers between the graphite surface and the bulk liquid, indicating an insignificant effect of vapor-IL interface on the ordered IL layers. The simulation also indicates that the imidazolium ring and butyl tail of the cation (bmim+) of the IL bottom layer lie flat on the graphite surface.

  8. Gravity-Driven Instability in a Liquid Film Overlying an Inhomogeneous Porous Layer

    Institute of Scientific and Technical Information of China (English)

    ZHAO Si-Cheng; LIU Qiu-Sheng; NGUYEN-THI Henri; BILLIA Bernard

    2011-01-01

    @@ A new model consisting of a liquid film overlying a saturated and inhomogeneous porous layer is investigated.We concentrate on effects of inhomogeneity on transition of instability modes.Influences of the averaged porosity and the gradient of porosity distribution on the instability behaviors of a liquid-porous layer system are emphasized.The average permeability of the porous layer is a key factor to determine the penetration of convection in the system.%A new model consisting of a liquid film overlying a saturated and inhomogeneous porous layer is investigated. We concentrate on effects of inhomogeneity on transition of instability modes. Influences of the averaged porosity and the gradient of porosity distribution on the instability behaviors of a liquid-porous layer system are emphasized.The average permeability of the porous layer is a key factor to determine the penetration of convection in the system.

  9. Superheating in linear polymers studied by ultrafast nanocalorimetry.

    Science.gov (United States)

    Minakov, A A; Wurm, A; Schick, C

    2007-05-01

    To study phase transition kinetics on submillisecond time scale a sensitive ultrafast nanocalorimeter was constructed. Controlled ultrafast cooling, as well as heating, up to 10(6) K/s was attained. The method was applied for the measurements of the superheating phenomenon in a set of linear polymers: iPS, PBT, PET, and iPP. A power law relation between the superheating and the heating rate holds in the heating rate range 10(-2) - 10(4) K/s. A limiting superheating of about 10% of the melting temperature was observed at rates above 10(4) - 10(5) K/s. This limit depends on annealing conditions before sample melting. The observed superheating limit, as well as the power law, can be accounted for the internal stresses near the crystalline amorphous interface in semicrystalline polymers induced by heating, which are related to the thermal expansion gradients inherent in a semicrystalline material.

  10. Heat treatment of scallop adductor muscle using superheated steam.

    Science.gov (United States)

    Abe, T; Miyashita, K

    2007-08-01

    Scallop (Patinopecten yessoensis) adductor muscles were heated using superheated steam (150 and 200 degrees C), boiling (98 degrees C), and normal steaming (95 degrees C). The amounts of amino acids, water-soluble peptides, and nucleotides, expressed as extractive nitrogen in scallop products, are very important elements of quality and taste. After 15-min heating of scallop muscles with normal steaming and boiling, respective losses of 50% and 64% of the extractive nitrogen were observed. However, most extractive nitrogen (> 86%) remained in the scallop muscles treated with superheated steam at 150 and 200 degrees C. Protective effects of superheated steam against elution loss of nitrogen compounds were also observed in amino acid analyses of the heated products. The scallop-muscle surface temperature during treatment with superheated steam increased more quickly than that with normal steaming and boiling. The rapid water loss and the surface protein denaturation engendered formation of a 30-mum-thick film covering the surface, which prevented extractive nitrogen loss from internal tissues. Superheated steam treatment at 200 degrees C caused browning, surface shrinkage, and 47% weight loss. In marked contrast, the appearance and the weight loss of sample treated at 150 degrees C were almost the same as those of normal steaming and boiling-treated samples. These results suggested that superheated steaming at 150 degrees C is an optimal heat treatment of scallop adductor muscles.

  11. Versatile alignment layer method for new types of liquid crystal photonic devices

    Energy Technology Data Exchange (ETDEWEB)

    Finnemeyer, V.; Bryant, D.; Lu, L.; Bos, P. [Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 (United States); Reich, R.; Clark, H.; Berry, S.; Bozler, C. [MIT Lincoln Laboratory, 244 Wood St., Lexington, Massachusetts 02420 (United States); Yaroshchuk, O. [Institute of Physics, NAS of Ukraine, 44 Prospect Nauky, Kyiv 03680 (Ukraine)

    2015-07-21

    Liquid crystal photonic devices are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. In this paper, we describe a method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer. However, previous research on such alignment layers has shown that they have limited stability, particularly against subsequent light exposure. As such, we further describe a method of utilizing a pre-polymer, infused into the microcavity along with the liquid crystal, to provide photostability. We demonstrate that the polymer layer, formed under ultraviolet irradiation of liquid crystal cells, has been effectively localized to a thin region near the substrate surface and provides a significant improvement in the photostability of the liquid crystal alignment. This versatile alignment layer method, capable of being utilized in devices from the described microcavities to displays, offers significant promise for new photonics applications.

  12. The propagation of Lamb waves in an anisotropic plate bordered with liquid layers

    Institute of Scientific and Technical Information of China (English)

    YAN Ping; ZHU Zhemin; DU Gonghuan

    2002-01-01

    Based on elastic wave propagation theory, the dispersion equation for a thin anisotropic plate (such as commonly used Zinc oxide in micro-transducers) bordered with liquid layers is derived. Higher symmetry crystals, such as orthorhombic, tetragonal, cubic, isotropic,are included in this analysis as well. For the case of one liquid layer loading, numerical calculations show that the phase velocity changes periodically with the thickness of the liquid layer.When the thickness 2d of the anisotropic plate is very small, mass sensing application of A0mode Lamb wave is also discussed.

  13. PROPAGATION OF LOVE WAVES IN PRESTRESSED PIEZOELECTRIC LAYERED STRUCTURES LOADED WITH VISCOUS LIQUID

    Institute of Scientific and Technical Information of China (English)

    Jianke Du; Kai Xian; Ji Wang; Yook-Kong Yong

    2008-01-01

    We investigate analytically the effect of initial stress in piezoelectric layered structures loaded with viscous liquid on the dispersive and attenuated characteristics of Love waves,which involves a thin piezoelectric layer bonded perfectly to an unbounded elastic substrate. The effects of initial stress in the piezoelectric layer and the viscous coefficient of the liquid on the phase velocity of Love waves are analyzed. Numerical results are presented and discussed. The analytical method and the results can be useful for the design of chemical and bioseusing liquid sensors.

  14. RESISTANCE EFFECT OF ELECTRIC DOUBLE LAYER ON LIQUID FLOW IN MICROCHANNEL

    Institute of Scientific and Technical Information of China (English)

    GONG Lei; WU Jian-kang

    2006-01-01

    Poisson-Boltzmann equation for EDL (electric double layer) and NavierStokes equation for liquid flows were numerically solved to investigate resistance effect of electric double layer on liquid flow in microchannel. The dimension analysis indicates that the resistance effect of electric double layer can be estimated by an electric resistance number, which is proportional to the square of the liquid dielectric constant and the solid surface zeta potential, and inverse-proportional to the liquid dynamic viscosity, electric conductivity and the square of the channel width. An "electric current density balancing" (ECDB) condition was proposed to evaluate the flow-induced streaming potential,instead of conventional "electric current balancing" (ECB) condition which may induce spurious local backflow in neighborhood of the solid wall of the microchannel. The numerical results of the flow rate loss ratio and velocity profile are also given to demonstrate the resistance effect of electric double layer in microchannel.

  15. Equations for a laminar boundary layer of a dilated liquid in a transverse magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Samokhin, V.N.

    1984-01-01

    A system of equations is examined which describes the magnetohydrodynamic boundary layer of a dilated liquid in a transverse magnetic field. The self modeling problem with an exponential law of change in the speed of the external stream and magnetic induction is studied. Localization of the perturbation in the liquid speed in the boundary layer is established and the change in the properties of the solution associated with this is shown.

  16. Searching for universal behaviour in superheated droplet detector with effective recoil nuclei

    Indian Academy of Sciences (India)

    Mala Das; Susnata Seth

    2013-06-01

    Energy calibration of superheated droplet detector is discussed in terms of the effective recoil nucleus threshold energy and the reduced superheat. This provides a universal energy calibration curve valid for different liquids used in this type of detector. Two widely used liquids, R114 and C4F10, one for neutron detection and the other for weakly interacting massive particles (WIMPs) dark matter search experiment, have been compared. Liquid having recoil nuclei with larger values of linear energy transfer (LET) provides better neutron- discrimination. Gamma () response of C4F10 has also been studied and the results are discussed. Behaviour of nucleation parameter with the effective recoil nucleus threshold energy and the reduced superheat have been explored.

  17. Direct measurements of ionic liquid layering at a single mica-liquid interface and in nano-films between two mica-liquid interfaces.

    Science.gov (United States)

    Griffin, Lucy R; Browning, Kathryn L; Clarke, Stuart M; Smith, Alexander M; Perkin, Susan; Skoda, M W A; Norman, Sarah E

    2016-12-21

    The layering of ionic liquids close to flat, charged interfaces has been identified previously through theoretical and some experimental measurements. Here we present evidence for oscillations in ion density ('layering') in a long chain ionic liquid (1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) near the interface with mica using two complementary approaches. Neutron reflection at the ionic liquid-mica interface is used to detect structure at a single interface, and surface force balance (SFB) measurements carried out with the same ionic liquid reveal oscillatory density in the liquid confined between two mica sheets. Our findings imply the interfacial structure is not induced by confinement alone. Structural forces between two mica surfaces extend to approximately twice the distance of the density oscillations measured at a single interface and have similar period in both cases.

  18. Superheating of ice crystals in antifreeze protein solutions

    Science.gov (United States)

    Celik, Yeliz; Graham, Laurie A.; Mok, Yee-Foong; Bar, Maya; Davies, Peter L.; Braslavsky, Ido

    2010-01-01

    It has been argued that for antifreeze proteins (AFPs) to stop ice crystal growth, they must irreversibly bind to the ice surface. Surface-adsorbed AFPs should also prevent ice from melting, but to date this has been demonstrated only in a qualitative manner. Here we present the first quantitative measurements of superheating of ice in AFP solutions. Superheated ice crystals were stable for hours above their equilibrium melting point, and the maximum superheating obtained was 0.44 °C. When melting commenced in this superheated regime, rapid melting of the crystals from a point on the surface was observed. This increase in melting temperature was more appreciable for hyperactive AFPs compared to the AFPs with moderate antifreeze activity. For each of the AFP solutions that exhibited superheating, the enhancement of the melting temperature was far smaller than the depression of the freezing temperature. The present findings clearly show that AFPs adsorb to ice surfaces as part of their mechanism of action, and this absorption leads to protection of ice against melting as well as freezing. PMID:20215465

  19. Superheating of ice crystals in antifreeze protein solutions.

    Science.gov (United States)

    Celik, Yeliz; Graham, Laurie A; Mok, Yee-Foong; Bar, Maya; Davies, Peter L; Braslavsky, Ido

    2010-03-23

    It has been argued that for antifreeze proteins (AFPs) to stop ice crystal growth, they must irreversibly bind to the ice surface. Surface-adsorbed AFPs should also prevent ice from melting, but to date this has been demonstrated only in a qualitative manner. Here we present the first quantitative measurements of superheating of ice in AFP solutions. Superheated ice crystals were stable for hours above their equilibrium melting point, and the maximum superheating obtained was 0.44 degrees C. When melting commenced in this superheated regime, rapid melting of the crystals from a point on the surface was observed. This increase in melting temperature was more appreciable for hyperactive AFPs compared to the AFPs with moderate antifreeze activity. For each of the AFP solutions that exhibited superheating, the enhancement of the melting temperature was far smaller than the depression of the freezing temperature. The present findings clearly show that AFPs adsorb to ice surfaces as part of their mechanism of action, and this absorption leads to protection of ice against melting as well as freezing.

  20. Electrochemical impedance spectroscopy on in-situ analysis of oxide layer formation in liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, M., E-mail: kondo.masatoshi@tokai-u.jp [Department of Nuclear Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Suzuki, N.; Nakajima, Y. [Department of Nuclear Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Tanaka, T.; Muroga, T. [National Institute for Fusion Science, Toki, Gifu 502-5292 (Japan)

    2014-10-15

    Graphical abstract: Some test materials (i.e. Fe, Cr, Y and JLF-1 steel) were immersed to liquid metal lead (Pb) mainly at 773 K as the working electrode of electrochemical impedance spectroscopy (EIS). Some oxide layers formed on the electrodes in liquid Pb were analyzed by EIS. The impedance response was summarized as semicircular Nyquist plot, and the electrical properties and the thickness of the oxide layers were evaluated in non-destructive manner. Large impedance due to the formation of Y oxide formed in liquid Pb was detected by EIS, though impedance of Fe oxide and Cr oxide could not be detected due to their small electro resistance. The time constant of the oxide layers was evaluated from the impedance information, and this value identified the types of oxides. The change of the time constant with the immersion time indicated the change of the electrical properties determined by the chemical composition and the crystal structure. The thickness of the oxide layer estimated by EIS agreed well with that evaluated by metallurgical analysis. The growth of Y oxide layer in the liquid Pb was successfully detected by EIS in non-destructive manner. - Highlights: • The electrical properties and the thickness of lead oxide layer formed in liquid Pb were obtained by electrochemical impedance spectroscopy (EIS). • The Fe oxide, Cr oxide and Fe–Cr oxide formed on the electrodes in liquid Pb were not detected by EIS due to their small electrical resistance. • The formation and the growth of Y oxide formed in liquid Pb was detected by EIS. - Abstract: Some test materials (i.e. Fe, Cr, Y and JLF-1 steel) were immersed to liquid metal lead (Pb) mainly at 773 K as the working electrode of electrochemical impedance spectroscopy (EIS). Some oxide layers formed on the electrodes in liquid Pb were analyzed by EIS. The impedance response was summarized as Nyquist plot, and the electrical properties and the thickness of the oxide layers were evaluated in non

  1. Microprobe of structure of crystal/liquid interface boundary layers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The molecular structures and its evolutive regularities within the boundary layers in the crystal growth of KDP and DKDP have been studied in real time by using holography and Raman microprobe. The experiments show that the molecular structure of mother solution within the boundary layers is distinctly different from that of the solutions alone. In this paper, the effects of cations within the boundary layers on the structure of solution are considered. Within the characteristic boundary layers, the effects of cations cause the changes in O-P-O bond angle, electronic density redistribution of the phosphate groups, and significant changes in the bond intensity, thus leading to the breaking of partial hydrogen bonds of the phosphate associations, the readjustment of geometry of anionic phosphate groups and desolvation, and the forming of the smectic ordering structure of the anions_cations. Finally, the crystallization unit of anion_cation should be formed at the proximate interface.

  2. Direct numerical simulation of gaseous mixing layers laden with multicomponent-liquid drops: liquid-specific effects

    Science.gov (United States)

    Le Clercq, Patrick C.; Bellan, Josette

    2005-06-01

    A representation of multicomponent-liquid (MC-liquid) composition as a linear combination of two single-Gamma probability distribution functions (PDFs) is used to describe a large number of MC-liquid drops evaporating in a gas flow. The PDF, called the double-Gamma PDF, depends on the molar mass. The gas-phase conservation equations are written in an Eulerian frame and the drops are described in a Lagrangian frame. Gas conservation equations for mass, momentum, species and energy are combined with differential conservation equations for the first four moments of the gas-composition PDF and coupled to the perfect gas equation of state. Source terms in all conservation equations account for the gas/drop interaction. The drop governing equations encompass differential conservation statements for position, mass, momentum, energy and four moments of the liquid-composition PDF. Simulations are performed for a three-dimensional mixing layer whose lower stream is initially laden with drops colder than the surrounding gas. Initial perturbations excite the layer to promote the double pairing of its four initial spanwise vortices to an ultimate vortex. During the layer evolution, the drops heat and evaporate. The results address the layer evolution, and the state of the gas and drops when layers reach a momentum-thickness maximum past the double vortex pairing. Of interest is the influence of the liquid composition on the development of the vortical features of the flow, on the vortical state reached after the second pairing, and on the gas temperature and composition. The MC-liquid simulations are initiated with a single-Gamma PDF composition so as to explore the development of the double-Gamma PDF. Examination of equivalent simulations with n-decane, diesel and three kerosenes as the liquid, permits assessment of the single-species versus the MC-liquid aspect, and of mixture composition specific effects. Global layer growth and global rotational characteristics are

  3. Studying the Dynamics of Breakdown of Thin Horizontal Liquid Layers with Local Heating

    Directory of Open Access Journals (Sweden)

    Spesivtsev Serafim

    2016-01-01

    Full Text Available Experimental study of liquid layers breakdown when heated locally from the substrate side was made. Water and ethanol were used as working liquids with a layer thickness of 300 μm. Basic steps of the breakdown process were found and mean velocities of the dry spot formation were determined; the values are 0.06 mm/sec for ethanol and 5.15 mm/sec for water. The formation of residual layer over the hot-spot before the breakdown has been found for both liquids. The creation of a droplet cluster near the heating region is observed when using water as a working fluid. It was shown that evaporation is one of the general factors influencing the process of layer breakdown and dry spot formation as well as thermocapillary effect.

  4. Raman Spectrum Analysis on the Solid-Liquid Boundary Layer of BGO Crystal Growth

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xia; YIN Shao-Tang; WAN Song-Ming; YOU Jing-Lin; CHEN Hui; ZHAO Si-Jie; ZHANG Qing-Li

    2007-01-01

    We study the Raman spectra of Bi4Ge3O12 crystal at different temperatures, as well as its melt. The structure characters of the single crystal, melt and growth solid-liquid boundary layer of BGO are investigated by their high-temperature Raman spectra for the first time. The rule of structure change of BGO crystal with increasing temperature is analysed. The results show that there exists [GeO4] polyhedral structure and Bi ion independently in BGO melt. The bridge bonds Bi-O-Bi and Bi-O-Ge appear in the crystal and at the boundary layer, but disappear in the melt. The structure of the growth solid-liquid boundary layer is similar to that of BGO crystal. In the melt, the long-range order structure of the crystal disappears. The thickness of the grovth solid-liquid boundary layer of BGO crystal is about 50 μm.

  5. Numerical calculation of superheating magnetic fields and currents for superconducting slabs

    Science.gov (United States)

    Landau, I. L.; Rinderer, L.

    1995-08-01

    Numerical calculations of superheating magnetic fields and superheating currents for superconducting slabs for a wide range of the sample thickness are presented. The calculations were made for low values of Ginzburg-Landau parameter κ, i.e., for type-1 superconductors. We propose also experimental procedures to measure superheating fields and currents in films and bulk samples.

  6. Acoustic response of superheated droplet detectors to neutrons

    Science.gov (United States)

    Gao, Size; Zhang, Guiying; Ni, Bangfa; Zhao, Changjun; Zhang, Huanqiao; Guan, Yongjing; Chen, Zhe; Xiao, Caijin; Liu, Chao; Liu, Cunxiong

    2012-03-01

    The search for dark matter (DM) is a hot field nowadays, a number of innovative techniques have emerged. The superheated droplet technique is relatively mature; however, it is recently revitalized in a number of frontier fields including the search for DM. In this work, the acoustic response of Superheated Droplet Detectors (SDDs) to neutrons was studied by using a 252Cf neutron source, SDDs developed by the China Institute of Atomic Energy, a sound sensor, a sound card and a PC. Sound signals were filtered. The characteristics of FFT spectra, power spectra and time constants were used to determine the authenticity of the bubbles analyzed.

  7. Ionic Liquids as Electrolytes for Electrochemical Double-Layer Capacitors: Structures that Optimize Specific Energy.

    Science.gov (United States)

    Mousavi, Maral P S; Wilson, Benjamin E; Kashefolgheta, Sadra; Anderson, Evan L; He, Siyao; Bühlmann, Philippe; Stein, Andreas

    2016-02-10

    Key parameters that influence the specific energy of electrochemical double-layer capacitors (EDLCs) are the double-layer capacitance and the operating potential of the cell. The operating potential of the cell is generally limited by the electrochemical window of the electrolyte solution, that is, the range of applied voltages within which the electrolyte or solvent is not reduced or oxidized. Ionic liquids are of interest as electrolytes for EDLCs because they offer relatively wide potential windows. Here, we provide a systematic study of the influence of the physical properties of ionic liquid electrolytes on the electrochemical stability and electrochemical performance (double-layer capacitance, specific energy) of EDLCs that employ a mesoporous carbon model electrode with uniform, highly interconnected mesopores (3DOm carbon). Several ionic liquids with structurally diverse anions (tetrafluoroborate, trifluoromethanesulfonate, trifluoromethanesulfonimide) and cations (imidazolium, ammonium, pyridinium, piperidinium, and pyrrolidinium) were investigated. We show that the cation size has a significant effect on the electrolyte viscosity and conductivity, as well as the capacitance of EDLCs. Imidazolium- and pyridinium-based ionic liquids provide the highest cell capacitance, and ammonium-based ionic liquids offer potential windows much larger than imidazolium and pyridinium ionic liquids. Increasing the chain length of the alkyl substituents in 1-alkyl-3-methylimidazolium trifluoromethanesulfonimide does not widen the potential window of the ionic liquid. We identified the ionic liquids that maximize the specific energies of EDLCs through the combined effects of their potential windows and the double-layer capacitance. The highest specific energies are obtained with ionic liquid electrolytes that possess moderate electrochemical stability, small ionic volumes, low viscosity, and hence high conductivity, the best performing ionic liquid tested being 1-ethyl-3

  8. Quantized layer growth at liquid-crystal surfaces

    DEFF Research Database (Denmark)

    Ocko, B. M.; Braslau, A.; Pershan, P. S.

    1986-01-01

    of the specular reflectivity is consistent with a sinusoidal density modulation, starting at the surface and terminating abruptly, after an integral number of bilayers. As the transition is approached the number of layers increases in quantized steps from zero to five before the bulk undergoes a first...

  9. Self-Restoration by Smectic Layer Structures of Monostable Ferroelectric Liquid Crystal in Flexible Devices

    Science.gov (United States)

    Fujikake, Hideo; Sato, Hiroto; Isaka, Fumito; Murashige, Takeshi; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    In this paper, we discuss a self-restoration phenomenon affecting smectic layer deformation and molecular alignment in monostable ferroelectric liquid crystals used for flexible displays. First, the mechanical stability of tilted ‘bookshelf’ structures of smectic layers anchored on substrates using alignment layers was examined by precisely shearing two substrates. The microscopic texture of a monostable ferroelectric liquid crystal showed tolerance to shearing and the self-restoration was thought to be due to a smectic layer reconnection phenomenon, whereas a conventional bistable ferroelectric liquid crystal film generated alignment defects due to the tilting of the stable molecular direction. We then fabricated a flexible monostable device containing fine polymer fiber networks, where anchoring of molecularly aligned polymer fibers led to the observation of monostable liquid crystal switching. A uniform liquid crystal alignment was maintained in a 100 mm× 100 mm device even after bending more than 10000 times at a minimum radius of curvature of 20 mm, due to the enhanced shearing tolerance of the smectic layer structure.

  10. Explosive boiling of a metallic glass superheated by nanosecond pulse laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, M. Q., E-mail: mqjiang@imech.ac.cn, E-mail: lhdai@lnm.imech.ac.cn [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Materials Physics, Westfälische Wilhelms-Universität Münster, Münster 48149 (Germany); Wei, Y. P. [Key Laboratory of Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Wilde, G. [Institute of Materials Physics, Westfälische Wilhelms-Universität Münster, Münster 48149 (Germany); Dai, L. H., E-mail: mqjiang@imech.ac.cn, E-mail: lhdai@lnm.imech.ac.cn [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-01-12

    We report an explosive boiling in a Zr-based (Vitreloy 1) bulk metallic glass irradiated by a nanosecond pulse laser with a single shot. This critical phenomenon is accompanied by the ejection of high-temperature matter from the target and the formation of a liquid-gas spinodal pattern on the irradiated area. An analytical model reveals that the glassy target experiences the normal heating (melting) and significant superheating, eventually culminating in explosive boiling near the spinodal limit. Furthermore, the time lag of nucleation and the critical radius of vapor bubbles are theoretically predicted, which are in agreement with the experimental observations. This study provides the investigation on the instability of a metallic glass liquid near the thermodynamic critical temperature.

  11. Mechanistic Model for Atomization of Superheated Liquid Jet Fuel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As air-breathing combustion applications advance, increased use of fuel for cooling, combined with cycle advancements, leads to a situation where the fuel can...

  12. Mechanistic Model for Atomization of Superheated Liquid Jet Fuel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As air-breathing combustion applications advance, increased use of fuel for cooling, combined with cycle advancements, leads to a situation where the fuel can become...

  13. Kapitza Resistance between Few-Layer Graphene and Water: Liquid Layering Effects

    DEFF Research Database (Denmark)

    Alexeev, Dmitry; Chen, Jie; Walther, Jens Honore;

    2015-01-01

    The Kapitza resistance (RK) between few-layer graphene (FLG) and water was studied using molecular dynamics simulations. The RK was found to depend on the number of the layers in the FLG though, surprisingly, not on the water blockthickness. This distinct size dependence is attributed to the larg...

  14. Superheated starch: A novel approach towards spreadable particle gels

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Woortman, A.J.J.

    2009-01-01

    When aqueous potato starch suspensions were heated into the solution state and cooled, spreadable particle gels were obtained with a spherulite morphology and a cream-like texture. This so-called superheated starch (SHS) exhibits more effective gelling properties than maltodextrin, which is

  15. La moral de los superhéroes

    Directory of Open Access Journals (Sweden)

    Jhon Rozo Mila

    2015-12-01

    Full Text Available Los superhéroes, el deber moral y la obligación; El caso de Spider-Man y los X-Men. Laura Victoria Bolaño Pérez; Universidad del Rosario, colección Ópera Prima, Bogotá, 2012, 309 págs.

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

    Institute of Scientific and Technical Information of China (English)

    Rong Liu; Qiusheng Liu

    2006-01-01

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

  17. A position-sensitive neutron spectrometer/dosimeter based on pressurized superheated drop (bubble) detectors

    Science.gov (United States)

    d'Errico, F.; Nath, R.; Holland, S. K.; Lamba, M.; Patz, S.; Rivard, M. J.

    2002-01-01

    A position-sensitive, superheated emulsion chamber (SEC) is introduced for three-dimensional (3D) spectrometry and dosimetry of fast neutrons. The detector is based on a fine suspension of octafluorocyclobutane droplets emulsified in a tissue-equivalent gel. This gel is highly viscous and immobilizes the bubbles at the location of their formation. At an operating temperature of 35°C, the droplets are moderately superheated and their evaporation is nucleated by the densely ionizing products of fast neutron interactions, with no response to sparsely ionizing radiations. Thus, when a neutron emitter such as a 252Cf brachytherapy source is inserted in the SEC, a bubble distribution forms around the source and makes the neutron field visible. The SEC is operated at different externally applied pressures that correspond to different response thresholds. These responses form a virtually orthogonal matrix which is suitable for spectrometry and allows the use of effective few channel unfolding procedures, yielding the spatial dependence of absorbed dose and neutron energy spectra in-tissue. Bubble spatial distributions in the chamber can be determined through optical tomography or magnetic resonance imaging (MRI). A 3D, steady-state MRI method has proven particularly effective for this purpose. After the imaging, the SEC can be pressurized above the halocarbon vapor tension in order to recondense the bubbles to the liquid phase. Within a few minutes, the device is annealed and ready to be used again for repeated measurements improving the bubble counting statistics.

  18. A position-sensitive neutron spectrometer/dosimeter based on pressurized superheated drop (bubble) detectors

    Energy Technology Data Exchange (ETDEWEB)

    D' Errico, F. E-mail: francesco.derrico@yale.edu; Nath, R.; Holland, S.K.; Lamba, M.; Patz, S.; Rivard, M.J

    2002-01-01

    A position-sensitive, superheated emulsion chamber (SEC) is introduced for three-dimensional (3D) spectrometry and dosimetry of fast neutrons. The detector is based on a fine suspension of octafluorocyclobutane droplets emulsified in a tissue-equivalent gel. This gel is highly viscous and immobilizes the bubbles at the location of their formation. At an operating temperature of 35 deg.C, the droplets are moderately superheated and their evaporation is nucleated by the densely ionizing products of fast neutron interactions, with no response to sparsely ionizing radiations. Thus, when a neutron emitter such as a {sup 252}Cf brachytherapy source is inserted in the SEC, a bubble distribution forms around the source and makes the neutron field visible. The SEC is operated at different externally applied pressures that correspond to different response thresholds. These responses form a virtually orthogonal matrix which is suitable for spectrometry and allows the use of effective few channel unfolding procedures, yielding the spatial dependence of absorbed dose and neutron energy spectra in-tissue. Bubble spatial distributions in the chamber can be determined through optical tomography or magnetic resonance imaging (MRI). A 3D, steady-state MRI method has proven particularly effective for this purpose. After the imaging, the SEC can be pressurized above the halocarbon vapor tension in order to recondense the bubbles to the liquid phase. Within a few minutes, the device is annealed and ready to be used again for repeated measurements improving the bubble counting statistics.

  19. Intrinsic noise of a superheated droplet detector for neutron background measurements in massively shielded facilities

    Science.gov (United States)

    Fernandes, Ana C.; Morlat, Tomoko A.; Felizardo, Miguel; Kling, Andreas; Marques, José G.; Prudêncio, Maria I.; Marques, Rosa; Carvalho, Fernando P.; Roche, Ignácio Lázaro; Girard, Thomas A.

    2017-09-01

    Superheated droplet detectors are a promising technique to the measurement of low-intensity neutron fields, as detectors can be rendered insensitive to minimum ionizing radiations. We report on the intrinsic neutron-induced signal of C2ClF5 devices fabricated by our group that originate from neutron- and alpha-emitting impurities in the detector constituents. The neutron background was calculated via Monte Carlo simulations using the MCNPX-PoliMi code in order to extract the recoil distributions following neutron interaction with the atoms of the superheated liquid. Various nuclear techniques were employed to characterise the detector materials with respect to source isotopes (238U, 232Th and 147Sm) for the normalisation of the simulations and also light elements (B, Li) having high (α, n) neutron production yields. We derived a background signal of 10-3 cts/day in a 1 liter detector of 1-3 wt.% C2ClF5, corresponding to a detection limit in the order of 10-8 n cm-2s-1. Direct measurements in a massively shielded underground facility for dark matter search have confirmed this result. With the borosilicate detector containers found to be the dominant background source in current detectors, possibilities for further noise reduction by 2 orders of magnitude based on selected container materials are discussed.

  20. First liquid-layer implosion experiments on the National Ignition Facility

    Science.gov (United States)

    Zylstra, Alex; Olson, R.; Leeper, R.; Kline, J.; Yi, S. A.; Peterson, R.; Bradley, P.; Haines, B.; Yin, L.; Wilson, D.; Herrmann, H.; Shah, R.; Biener, J.; Braun, T.; Kozioziemski, B.; Berzak Hopkins, L.; Hamza, A.; Nikroo, A.; Meezan, N.; Biener, M.; Sater, J.; Walters, C.

    2016-10-01

    Replacing the standard ice layer in an ignition design with a liquid layer allows fielding the target with a higher central vapor pressure, leading to reduced implosion convergence ratio (CR). At lower CR, the implosions are expected to be more robust to instabilities and asymmetries than standard ignition designs. The first liquid-layer implosions on the National Ignition Facility (NIF) have been performed by wicking the liquid fuel into a supporting foam. A 3-shot series has been conducted at CR=14-16 using a HDC ablator driven by a 3-shock pulse in a near-vacuum Au hohlraum; data and inferred quantities, such as pressure, show good agreement with expectations.

  1. Dielectric relaxation behavior of nematic liquid crystal cell using β-cyclodextrin as an alignment layer

    Directory of Open Access Journals (Sweden)

    Marwa Sahraoui

    2016-02-01

    Full Text Available In the present investigation, we report the dielectric properties of a symmetric Nematic Liquid Crystal (NLC cell using Beta Cyclodextrins (β-CD as alignment layers. These layers were deposited onto Indium Tin Oxide (ITO surface by thermal evaporation and then characterized using contact angle measurement. This revealed a hydrophilic character attributed to the presence of hydroxyl groups. Morphological study was carried out by Scanning Electronic Microscopy (SEM. The dynamic impedance study of the Liquid Crystal (LC cell in a wide frequency range from 1mHz to 13MHz was reported. It was found that the β-CD alignment layer had a blocking effect on the NLC cell at a high frequency range. We also report the relaxation mechanism of NLC cell which is modeled by an appropriate equivalent circuit in order to understand the electrical properties of the liquid crystal cell and to investigate the processes taking place at different interfaces. 

  2. Surface Wave Propagation in a Microstretch Thermoelastic Diffusion Material under an Inviscid Liquid Layer

    Directory of Open Access Journals (Sweden)

    Rajneesh Kumar

    2014-01-01

    Full Text Available The present investigation deals with the propagation of Rayleigh type surface waves in an isotropic microstretch thermoelastic diffusion solid half space under a layer of inviscid liquid. The secular equation for surface waves in compact form is derived after developing the mathematical model. The dispersion curves giving the phase velocity and attenuation coefficients with wave number are plotted graphically to depict the effect of an imperfect boundary alongwith the relaxation times in a microstretch thermoelastic diffusion solid half space under a homogeneous inviscid liquid layer for thermally insulated, impermeable boundaries and isothermal, isoconcentrated boundaries, respectively. In addition, normal velocity component is also plotted in the liquid layer. Several cases of interest under different conditions are also deduced and discussed.

  3. Experimental Investigation of Thermocapillary Convection in a Liquid Layer with Evaporating Interface

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-Qiang; LIU Qiu-Sheng

    2008-01-01

    Thermocapillary convection coupling with the evaporation effect of evaporating liquids is studied experimentally.This study focused on an evaporation liquid layer in a rectangular cavity subjected to a horizontal temperature gradient when the top evaporating surface is open to air, while most previous works only studied pure thermocapillary convection without evaporation. Two liquids with different evaporating rates are used to study the coupling of evaporation and thermocapillary convection, and the interracial temperature profiles for different temperature gradients are measured. The experimental results indicate evidently the influence of evaporation effect on the thermocapillary convection and interracial temperature profiles. The steady multicellular flow and the oscillatory multicellular flow in the evaporation liquid layer are observed by using the particle-image-velocimetry method.

  4. Cinnamate-functionalized hyperbranched polymer as liquid crystal photo-alignment layer

    Institute of Scientific and Technical Information of China (English)

    Bin Jun Shen; Zheng Xie; Ya Ning He; Yan Qing Lian

    2008-01-01

    In this work, 4-methoxylcirmamoyl chloride was reacted with a commercial hyperbranched polymer (Boltom~TM H30) to prepare a hyperbranched photosensitive polymer (H30-Ci). The polymer was characterized by UV absorption spectrum and 1H-NMR spectrum. After processed by Linearly Polarized Polymerization (LPP) method, the spin-coated films of H30-Ci were used as photo-alignment layers to assemble liquid crystal (LC) cells containing nematic liquid crystal (5CB). The observation by polarized microscope showed that the H30-Ci blended with a linear polymer (BP-AN-Ci) photo-alignment layers could align LC molecules in a very uniform way.

  5. Steady thermocapillary flows in a two-layer liquid system with flat interfaces

    Science.gov (United States)

    del Arco, E. Crespo; Extremet, G. P.; Sani, R. L.

    1993-01-01

    Steady thermocapillary convection is studied in a system of two flat, superposed layers of immiscible liquids with two fluid-fluid interfaces in a configuration similar to that of an encapsulated crystal growth. The layers are bounded on the sides by isothermal vertical walls maintained at different constant temperatures. A simplified analytical solution is used initially to explore different potential flow regimes in a parameter space of large dimensionality. Then the coupled Navier-Stokes and heat transfer equations are solved numerically with a finite element method via FIDAP, in a rectangular cavity filled with two immiscible liquids in the absence of a gravitational field.

  6. Surface wave propagation in a double liquid layer over a liquid-saturated porous half-space

    Indian Academy of Sciences (India)

    Rajneesh Kumar; Aseem Miglani; N R Garg

    2002-12-01

    The frequency equation is derived for surface waves in a liquidsaturated porous half-space supporting a double layer, that of inhomogeneous and homogeneous liquids. Asymptotic approximations of Bessel functions are used for long and short wavelength cases. Certain other problems are discussed as special cases. Velocity ratio (phase and group velocity) is obtained as a function of wavenumber and the results are shown graphically.

  7. Experimental and Analytical Method for Determining a Drag Coefficient of the Double-Layer Liquid Separator

    Directory of Open Access Journals (Sweden)

    A. A. Pozhalostin

    2015-01-01

    Full Text Available The paper considers a problem of small axisymmetric oscillations of two-layer liquid with a foam-based separator. The separator is supposed to be rigid and non-deformable, liquid flow through the separator is modeled as a stream with a certain linear-viscous resistance. The liquid is assumed to be ideal and incompressible, its stream being potential. The paper presents experimental and analytical method for finding such a drag coefficient.The work [1] considered the problem of oscillations of a two-layer liquid divided by nondeforming permeable separator where, taking into consideration the interaction between liquid and separator, a reduced drag coefficient is introduced, which is expected to be determined experimentally, thereby generalizing the results of works [4] and [5] in case of moving two-layer liquid through a resistance. The work [6] investigated the motion of ideal incompressible and non-stratified liquid together with the elastic bottom. The work [7] studied a stability of the free liquid surface in low gravity. The paper [8] examined free axially symmetric oscillations of a two-layer liquid with an impermeable separator.Analytical dependence for the drag coefficient obtained in the paper [1] contains the frequency values of free harmonic oscillation system with no resistance (with a missing delimiter and the damping coefficient for the system with resistance (with a separator available. These values can be obtained experimentally if the tank model oscillations with a separator and without it are excited and the natural frequencies of these oscillations are determined. The model under consideration can be used to analyze dynamic interaction between liquid and phase separator of the upper stage or launch vehicle stage and provide ground experimental method for the starting systems from the gravity-free state and low gravity one.The article shows the relationship of the analytic dependence of the damping coefficient at symmetric

  8. Laminar film condensation from downward flowing superheated vapors onto a non-isothermal sphere

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, C.H. [Dept. of Mold and Die Engineering, National Kaohsiung Univ. of Applied Sciences, Kaohsiung (Taiwan)

    2001-11-01

    A model is developed for the study of mixed convection film condensation from downward flowing superheated vapors onto a sphere with variable wall temperature. The model combined natural convection dominated and forced convection dominated film condensation, including effects of superheated vapor, pressure gradient and wall temperature variation can be solved numerically by the fourth-order Runge-Kutta technique. By the present numerical approach, the mean heat transfer is evaluated up to the critical angle of the condensate layer, {phi}{sub c}. In general, the result of mean heat transfer shows that, as A, the wall-temperature amplitude, increases, the value of NuRe{sup -1/2} with inclusion of P, the pressure gradient effect, goes down slightly, however, the value of NuRe{sup -1/2} with the pressure gradient effect ignored will remain almost uniform. Further, for P=2.0, the mean heat transfer coefficient increases significantly, by 8.6-23.9%, depending on A, as the superheat parameter, Sp, increases within a practical range. (orig.)

  9. Smectic Layer Deformation of Ferroelectric Liquid Crystal Sandwiched between Polymer Walls with Anchoring Effects

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Ikehata, Seiichiro; Sato, Fumio

    2002-05-01

    We studied smectic layer structures of ferroelectric liquid crystal (FLC) formed in elongated small spaces surrounded by molecule-aligned polymer walls and rubbed polyimide alignment layers. The polymer walls, which are parallel to the rubbing direction and vertical to the alignment layers, were formed by the photopolymerization of an aligned monomer under patterned ultraviolet light irradiation. From the observation of the alignment textures of the FLC between the polymer walls with a polarizing microscope, it was found that the smectic layer structure was changed from vertical plane bending alignment (chevron structure), as observed with a conventional surface-stabilized FLC, into horizontal plane bending, as the interval between the polymer walls decreased. It is thought that the smectic layer structure is governed by the competition between the anchoring effects of the alignment polyimide layers and the molecule-aligned polymer walls.

  10. Bias-dependent molecular-level structure of electrical double layer in ionic liquid on graphite.

    Science.gov (United States)

    Black, Jennifer M; Walters, Deron; Labuda, Aleksander; Feng, Guang; Hillesheim, Patrick C; Dai, Sheng; Cummings, Peter T; Kalinin, Sergei V; Proksch, Roger; Balke, Nina

    2013-01-01

    Here we report the bias-evolution of the electrical double layer structure of an ionic liquid on highly ordered pyrolytic graphite measured by atomic force microscopy. We observe reconfiguration under applied bias and the orientational transitions in the Stern layer. The synergy between molecular dynamics simulation and experiment provides a comprehensive picture of structural phenomena and long and short-range interactions, which improves our understanding of the mechanism of charge storage on a molecular level.

  11. Investigation of Interface between Ge Electrodes and Ionic Liquid Electrolytes for Electric Double Layer Capacitors

    Science.gov (United States)

    Abeysinghe, R. M.; Oguchi, H.; Kuwano, H.

    2016-11-01

    This study discusses novel way of use of ionic liquids to develop Ge-based electrodes for electric double layer capacitors (EDLC). We found that ionic liquids change their electrochemical properties depending on the amount of the absorbed water. Wet ionic liquids work as solvents to dissolve Ge and make porous structures, whereas dry ones work as electrolytes of the EDLCs. The former property was used to increase surface area of the electrodes which is desired to increase the capacity of EDLCs. This method showed another advantage in contrast to the dry ionic liquids; wet ones could fill the complex Ge pores in parallel to porous structure formation. Finally, after porous formation, we dried the ionic liquid at 100 °C and prepared the EDLCs composed of Ge porous electrodes. Cyclic voltammetry and impedance measurements indicated that the obtained devices can work as EDLCs.

  12. Tunable terahertz fishnet metamaterials based on thin nematic liquid crystal layers for fast switching.

    Science.gov (United States)

    Zografopoulos, Dimitrios C; Beccherelli, Romeo

    2015-08-14

    The electrically tunable properties of liquid-crystal fishnet metamaterials are theoretically investigated in the terahertz spectrum. A nematic liquid crystal layer is introduced between two fishnet metallic structures, forming a voltage-controlled metamaterial cavity. Tuning of the nematic molecular orientation is shown to shift the magnetic resonance frequency of the metamaterial and its overall electromagnetic response. A shift higher than 150 GHz is predicted for common dielectric and liquid crystalline materials used in terahertz technology and for low applied voltage values. Owing to the few micron-thick liquid crystal cell, the response speed of the tunable metamaterial is calculated as orders of magnitude faster than in demonstrated liquid-crystal based non-resonant terahertz components. Such tunable metamaterial elements are proposed for the advanced control of electromagnetic wave propagation in terahertz applications.

  13. Theoretical analysis of a Love wave biosensor in liquid with a viscoelastic wave guiding layer

    Science.gov (United States)

    Wu, Huiyan; Xiong, Xiangming; Zu, Hongfei; Wang, James H.-C.; Wang, Qing-Ming

    2017-02-01

    The Love mode surface acoustic wave biosensor is considered as one of the most promising probing methods in biomedical research and diagnosis, which has been applied to detect the mechano-biological behaviors of cells attached to the surface of the device. Recent studies have reported the structural and functional optimization of Love wave biosensors for reducing propagation loss and improving sensitivity; however, the relevant device performance needs to be analyzed in depth in terms of device structure, electromechanical properties of piezoelectric crystal substrates, viscoelastic properties of wave guiding layers, and the effect of liquid loading. In this study, a 36° YX-LiTaO3 based Love wave sensor with a parylene-C wave guiding layer is considered as a cell-based biosensor. A theoretical model is proposed to describe the Love wave propagation in the wave guiding layer and penetration in the liquid medium. Decay length δ for the Love wave penetration in liquid is found to be in the order of ˜50 nm, which agrees well with experimental observations. In addition, the effects of the viscoelastic wave guiding layer and liquid medium on the effective electromechanical coupling coefficient K2 of the sensor, the propagation loss PL, and sensor response to mass loading (mass sensitivity) are investigated. The numerical results indicate that the maximum propagation velocity is found at h/λ = 0, where h is the thickness of the wave guiding layer and λ is the wavelength; and the optimal coupling coefficient and mass sensitivity can be obtained at h/λ = 0.045 and h/λ = ˜0.06 in a vacuum or ˜0.058 in water, respectively. For a good combination of these device performance parameters, it is suggested that the optimal wave guiding layer thickness in a Love wave biosensor is at the vicinity of h/λ = ˜0.05 in a vacuum and ˜0.048 in liquid (water).

  14. Investigations of structural transformation within metal (austenite chromium-manganese steel) at the external surface of steam superheating tubes

    Science.gov (United States)

    Bogachev, V. A.; Pshechenkova, T. P.; Shumovskaya, M. A.

    2016-04-01

    The elemental composition of an altered layer at the external surface of a steam superheating tube of grade DI59 steel is investigated after long-term operation. It is shown that the layer is located between a scale and a matrix and depleted by silicon, manganese, copper, and chromium with the maximum oxidizer affinity, enriched by iron and nickel to 90%, and mainly composed of the α-Fe phase (ferrite) with the ferromagnetic properties. The layer formed as a result of selective oxidation and diffusion from the matrix into the metal scale with the less standard free energy of the formation of sulfides and oxides. A magnetic ferrite meter is used in the experimental investigation of the layer evolution by testing grade DI59 steel for heat resistance in air environment at temperatures of 585, 650, and 700°C for 15 × 103 h; creep at a temperature of 750°C and a stress of 60 MPa; and long-term strength at temperatures of 700 and 750°C and stresses of from 30 to 80 MPa. Specimens for tests are made of tubes under as-received conditions. The relationship between the ferrite phase content in the surface metal layer and the temperature and time of test is determined. The dependence is developed to evaluate the equivalent temperature for operation of the external surface of steam superheating tubes using data of magnetic ferritometry. It is shown that operation temperatures that are determined by the ferrite phase content and the σ phase concentration in the metal structure of steam superheating tubes with the significant operating time are close. It is proposed to use magnetic ferritometry for revelation of thermal nonuniformity and worst tubes of steam superheaters of HPP boilers.

  15. Droplet impact on superheated micro-structured surfaces

    NARCIS (Netherlands)

    Tran, A.T.; Staat, H.J.J.; Susarrey-Arce, A.; Foertsch, T.C.; Houselt, van A.; Gardeniers, J.G.E.; Prosperetti, A.; Lohse, D.; Sun, C.

    2013-01-01

    When a droplet impacts upon a surface heated above the liquid's boiling point, the droplet either comes into contact with the surface and boils immediately (contact boiling), or is supported by a developing vapor layer and bounces back (film boiling, or Leidenfrost state). We study the transition be

  16. Light scattering from impurity enhanced liquid layers in polycrystalline ice

    Science.gov (United States)

    Thomson, E. S.; Wettlaufer, J. S.; Wilen, L. A.

    2009-12-01

    Impurity enhanced grain boundary premelting underlies a wide range of geophysical phenomena throughout the cryosphere. In particular, it is known that when water droplets freeze in the atmosphere they are highly polycrystalline and impurities are rejected into grain boundaries. The predicted character and sensitivity of grain boundaries to impurities close to the melting point precludes the use of standard techniques for imaging the interface. Unlike their larger more macroscopic relatives such as veins (3 grain intersections) and nodes (4 grain intersections), grain boundaries do not submit to optical microscopy. However, using an experimental light scattering method grain boundary changes can be measured as a function of thermodynamic variables. Accurate analysis of the light scattering data generated using this method requires a full theory of light propagation through the grain boundary layer straddled by ice crystals. Here we present a theory for light scattering from such a boundary, experimental data using NaCl as a dopant, and dicsuss atmospheric implications from the troposphere to the stratosphere.

  17. Growth of high purity semiconductor epitaxial layers by liquid phase epitaxy and their characterization

    Indian Academy of Sciences (India)

    S Dhar

    2005-07-01

    This paper briefly describes our work and the results on the growth of several III–V epitaxial semiconductor materials in high purity form by liquid phase epitaxy (LPE) technique. Various possible sources of impurities in such growth are listed and step-by-step procedures adopted to reduce them are discussed in particular reference to the growth of GaAs layers. The technique of growing very high purity layers by treating the melt with erbium is described for the growth of InGaAs and GaSb layers.

  18. Electrically Rotatable Polarizer Using One-Dimensional Photonic Crystal with a Nematic Liquid Crystal Defect Layer

    Directory of Open Access Journals (Sweden)

    Ryotaro Ozaki

    2015-09-01

    Full Text Available Polarization characteristics of defect mode peaks in a one-dimensional (1D photonic crystal (PC with a nematic liquid crystal (NLC defect layer have been investigated. Two different polarized defect modes are observed in a stop band. One group of defect modes is polarized along the long molecular axis of the NLC, whereas another group is polarized along its short axis. Polarizations of the defect modes can be tuned by field-induced in-plane reorientation of the NLC in the defect layer. The polarization properties of the 1D PC with the NLC defect layer is also investigated by the finite difference time domain (FDTD simulation.

  19. Obliquity of the Galilean satellites: The influence of a global internal liquid layer

    CERN Document Server

    Baland, R -M; Van Hoolst, T

    2012-01-01

    The obliquity of the Galilean satellites is small but not yet observed. Studies of cycloidal lineaments and strike-slip fault patterns on Europa suggest that Europa's obliquity is about 1 deg, although theoretical models of the obliquity predict the obliquity to be one order of magnitude smaller for an entirely solid Europa. Here, we investigate the influence of a global liquid layer on the obliquity of the Galilean satellites. Io most likely has a fully liquid core, while Europa, Ganymede, and Callisto are thought to have an internal global liquid water ocean beneath an external ice shell. We use a model for the obliquity based on a Cassini state model extended to the presence of an internal liquid layer and the internal gravitational and pressure torques induced by the presence of this layer. We find that the obliquity of Io only weakly depends on the different internal structure models considered, because of the weak influence of the liquid core which is therefore almost impossible to detect through observ...

  20. Thermo/Soluto-capillary instabilities in evaporating bi-component liquid layers using DNS

    Science.gov (United States)

    Williams, Adam; Sáenz, Pedro; Sefiane, Khellil; Valluri, Prashant

    2016-11-01

    We investigate the stability, flow dynamics and evaporation kinetics of bi-component miscible liquid layers subject to a horizontal temperature gradient by means of two-phase direct numerical simulation. Flow is dominated by surface tension and driven by both thermal and solutal Marangoni effects, in which thermophoresis and mixture thermodynamics play a role. We employ a 3D model based on the Volume-of-Fluid method to account for the deformable liquid-gas interface. We note that the addition of a second species to the liquid phase affects the stability of the laterally heated layer over the single component case. We focus on systems with low Prandtl numbers (Pr <1) and find that the layer is unstable for a certain critical Marangoni number, exhibiting the so-called hydrothermal waves. The structure of internal flow is a strong function of the instability and this we are also able to determine. Phase-separation/segregation within the liquid is more pronounced in evaporating systems, as is its effects on the hydrothermal waves. Our results show that solutal Marangoni convection is not only stronger in evaporating systems but also has a destabilising effect on the layer. EPSRC - EP/K00963X/1.

  1. Effects of boundary layer and liquid viscosity and compressible air on sloshing characteristics

    Science.gov (United States)

    Zou, Chang-Fang; Wang, De-Yu; Cai, Zhong-Hua

    2015-07-01

    In this paper, numerical investigations for tank sloshing, based on commercial CFD package FLUENT, are performed to study effects of boundary layer grid, liquid viscosity and compressible air on sloshing pressure, wave height and rising time of impact pressure. Also, sloshing experiments for liquids of different viscosity are carried out to validate the numerical results. Through comparison of numerical and experimental results, a computational model including boundary layer grid can predict the sloshing pressure more accurately. Energy dissipation due to viscous friction leads to reduction of sloshing pressure and wave elevation. Sloshing pressure is also reduced because of cushion effect of compressible air. Due to high viscosity damping effect and compressible air effect, the rising time of impact pressure becomes longer. It is also found that liquid viscosity and compressible air influence distribution of dynamic pressure along the vertical tank wall.

  2. Investigation of surface charge density on solid-liquid interfaces by modulating the electrical double layer.

    Science.gov (United States)

    Moon, Jong Kyun; Song, Myung Won; Pak, Hyuk Kyu

    2015-05-20

    A solid surface in contact with water or aqueous solution usually carries specific electric charges. These surface charges attract counter ions from the liquid side. Since the geometry of opposite charge distribution parallel to the solid-liquid interface is similar to that of a capacitor, it is called an electrical double layer capacitor (EDLC). Therefore, there is an electrical potential difference across an EDLC in equilibrium. When a liquid bridge is formed between two conducting plates, the system behaves as two serially connected EDLCs. In this work, we propose a new method for investigating the surface charge density on solid-liquid interfaces. By mechanically modulating the electrical double layers and simultaneously applying a dc bias voltage across the plates, an ac electric current can be generated. By measuring the voltage drop across a load resistor as a function of bias voltage, we can study the surface charge density on solid-liquid interfaces. Our experimental results agree very well with the simple equivalent electrical circuit model proposed here. Furthermore, using this method, one can determine the polarity of the adsorbed state on the solid surface depending on the material used. We expect this method to aid in the study of electrical phenomena on solid-liquid interfaces.

  3. Numerical simulation of liquid-layer breakup on a moving wall due to an impinging jet

    Science.gov (United States)

    Yu, Taejong; Moon, Hojoon; You, Donghyun; Kim, Dokyun; Ovsyannikov, Andrey

    2014-11-01

    Jet wiping, which is a hydrodynamic method for controlling the liquid film thickness in coating processes, is constrained by a rather violent film instability called splashing. The instability is characterized by the ejection of droplets from the runback flow and results in an explosion of the film. The splashing phenomenon degrades the final coating quality. In the present research, a volume-of-fluid (VOF)-based method, which is developed at Cascade Technologies, is employed to simulate the air-liquid multiphase flow dynamics. The present numerical method is based on an unstructured-grid unsplit geometric VOF scheme and guarantees strict conservation of mass of two-phase flow, The simulation results are compared with experimental measurements such as the liquid-film thickness before and after the jet wiping, wall pressure and shear stress distributions. The trajectories of liquid droplets due to the fluid motion entrained by the gas-jet operation, are also qualitatively compared with experimental visualization. Physical phenomena observed during the liquid-layer breakup due to an impinging jet is characterized in order to develop ideas for controlling the liquid-layer instability and resulting splash generation and propagation. Supported by the Grant NRF-2012R1A1A2003699, the Brain Korea 21+ program, POSCO, and 2014 CTR Summer Program.

  4. Thermal Rayleigh-Marangoni convection in a three-layer liquid-metal-battery model

    Science.gov (United States)

    Köllner, Thomas; Boeck, Thomas; Schumacher, Jörg

    2017-05-01

    The combined effects of buoyancy-driven Rayleigh-Bénard convection (RC) and surface tension-driven Marangoni convection (MC) are studied in a triple-layer configuration which serves as a simplified model for a liquid metal battery (LMB). The three-layer model consists of a liquid metal alloy cathode, a molten salt separation layer, and a liquid metal anode at the top. Convection is triggered by the temperature gradient between the hot electrolyte and the colder electrodes, which is a consequence of the release of resistive heat during operation. We present a linear stability analysis of the state of pure thermal conduction in combination with three-dimensional direct numerical simulations of the nonlinear turbulent evolution on the basis of a pseudospectral method. Five different modes of convection are identified in the configuration, which are partly coupled to each other: RC in the upper electrode, RC with internal heating in the molten salt layer, and MC at both interfaces between molten salt and electrode as well as anticonvection in the middle layer and lower electrode. The linear stability analysis confirms that the additional Marangoni effect in the present setup increases the growth rates of the linearly unstable modes, i.e., Marangoni and Rayleigh-Bénard instability act together in the molten salt layer. The critical Grashof and Marangoni numbers decrease with increasing middle layer thickness. The calculated thresholds for the onset of convection are found for realistic current densities of laboratory-sized LMBs. The global turbulent heat transfer follows scaling predictions for internally heated RC. The global turbulent momentum transfer is comparable with turbulent convection in the classical Rayleigh-Bénard case. In summary, our studies show that incorporating Marangoni effects generates smaller flow structures, alters the velocity magnitudes, and enhances the turbulent heat transfer across the triple-layer configuration.

  5. Layering of [BMIM]+-based ionic liquids at a charged sapphire interface.

    Science.gov (United States)

    Mezger, Markus; Schramm, Sebastian; Schröder, Heiko; Reichert, Harald; Deutsch, Moshe; De Souza, Emerson J; Okasinski, John S; Ocko, Benjamin M; Honkimäki, Veijo; Dosch, Helmut

    2009-09-07

    The structure of two model room temperature ionic liquids, [BMIM](+)[PF(6)](-) and [BMIM](+)[BF(4)](-), near the solid/liquid interface with charged Al(2)O(3)(0001) (sapphire) was determined with subnanometer resolution by high energy (72.5 keV) x-ray reflectivity. [BMIM](+)[PF(6)](-) exhibits alternately charged, exponentially decaying, near-surface layering. By contrast, the smaller-anion compound, [BMIM](+)[BF(4)](-), shows only a single layer of enhanced electron density at the interface. The different layering behaviors, and their characteristic length scales, correspond well to the different bulk diffraction patterns, also measured in this study. Complementary measurements of the surface and interface energies showed no significant different between the two RTILs. The combined bulk-interface results support the conclusion that the interfacial ordering is dominated by the same electrostatic ion-ion interactions dominating the bulk correlations, with hydrogen bonding and dispersion interactions playing only a minor role.

  6. Instabilities in two-liquid layers subject to a horizontal temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Madruga, S.; Lebon, G. [Liege University, Departement AGO, Liege (Belgium); Perez-Garcia, C. [Universidad de Navarra, Instituto de Fisica, Pamplona (Spain); Univ. Navarra, Depto. Ingen. Mecanica, E. T. S. Ingenieros (TECNUN), San Sebastian (Spain)

    2004-11-01

    We study theoretically the stability of two superposed fluid layers heated laterally. The fluids are supposed to be immiscible, the interface undeformable and of infinite horizontal extension. Combined thermocapillary and buoyancy forces give rise to a basic flow when a temperature difference is applied. The calculations are performed for a melt of GaAs under a layer of molten B{sub 2}O{sub 3}, a configuration of considerable technological importance. Four different flow patterns and five temperature configurations are found for the basic state in this system. A linear stability analysis shows that the basic state may be destabilized by oscillatory motions leading to the so-called hydrothermal waves. Depending on the relative height of the two layers these hydrothermal waves propagate parallel or perpendicular to the temperature gradient. This analysis reveals that these perturbations can alter significantly the liquid flow in the liquid-encapsulated crystal growth techniques. (orig.)

  7. Fuzzy cascade control based on control's history for superheated temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Guangjun; LI Gang; SHEN Shuguang

    2007-01-01

    To address the characteristics of the large delay and uncertainty of superheated temperature,a new cascade control system is presented based on control's history.Based on the analysis of the control objects' dynamic characteristics,historical control information (substituting for the deviation change rate) is used as the basis for decision-making of the fuzzy control.Therefore,the changing trend of the controlled variable can be accurately reflected.Furthermore,a proportional component is introduced,the advantages of PID and fuzzy controllers are integrated,and the structure weaknesses of conventional fuzzy controllers are overcome.Simulation shows that this control method can effectively reduce the adverse impact of the delay on control effects and,therefore,exhibit strong adaptability by comparing the superheated temperature control system by this controller with PID and conventional fuzzy controllers.

  8. Superheated Droplet Detectors as CDM Detectors The SIMPLE Experiment

    CERN Document Server

    Collar, J I; Limagne, D; Waysand, G

    1996-01-01

    Superheated Droplet Detectors (SDDs) are becoming commonplace in neutron personnel dosimetry. Their total insensitivity to minimum ionizing radiation (while responsive to nuclear recoils of energies ~ few keV), together with their low cost, ease of production, and operation at room temperature and 1 atm makes them ideal for Cold Dark Matter (CDM) searches. SDD's are optimal for the exploration of the spin-dependent neutralino coupling due to their high fluorine content. The status of SIMPLE (Superheated Instrument for Massive ParticLe Experiments) is presented. Under realistic background considerations, we expect an improvement in the present Cold Dark Matter sensitivity of 2-3 orders of magnitude after ~1 kg-y of data acquisition.

  9. AUTOMATIC CONTROL SYSTEM OF THE DRUM BOILER SUPERHEATED STEAM TEMPERATURE.

    Directory of Open Access Journals (Sweden)

    Juravliov A.A.

    2006-04-01

    Full Text Available The control system of the temperature of the superheated steam of the drum boiler is examined. Main features of the system are the PI-controller in the external control loop and introduction of the functional component of the error signal of the external control loop with the negative feedback of the error signal between the prescribed value of steam flowrate and the signal of the steam flowrate in the exit of the boiler in the internal control loop.

  10. Liquid crystal alignment in nanoporous anodic aluminum oxide layer for LCD panel applications.

    Science.gov (United States)

    Hong, Chitsung; Tang, Tsung-Ta; Hung, Chi-Yu; Pan, Ru-Pin; Fang, Weileun

    2010-07-16

    This paper reports the implementation and integration of a self-assembled nanoporous anodic aluminum oxide (np-AAO) film and liquid crystal (LC) on an ITO-glass substrate for liquid crystal display (LCD) panel applications. An np-AAO layer with a nanopore array acts as the vertical alignment layer to easily and uniformly align the LC molecules. Moreover, the np-AAO nanoalignment layer provides outstanding material properties, such as being inorganic with good transmittance, and colorless on ITO-glass substrates. In this application, an LCD panel, with the LC on the np-AAO nanoalignment layer, is successfully implemented on an ITO-glass substrate, and its performance is demonstrated. The measurements show that the LCD panel, consisting of an ITO-glass substrate and an np-AAO layer, has a transmittance of 60-80%. In addition, the LCD panel switches from a black state to a bright state at 3 V(rms), with a response time of 62.5 ms. In summary, this paper demonstrates the alignment of LC on an np-AAO layer for LCD applications.

  11. Dynamic behavior of superheated steam and ways of control

    Institute of Scientific and Technical Information of China (English)

    Xu LI

    2008-01-01

    A simple way of calculating the dynamic behavior of a superheater is presented. A comparison of the measured data with the calculated result verifies the accuracy of this simple method. It is the first time that a phase compensation for real roots, i.e., the twin lead/lag loop which is facile for engineering applications, is used in superheated steam temperature control. Numerous simu-lation results show that both the response time lapse and maximal dynamic deviation are greatly reduced. Moreover, a formula to calculate the setting parameters is presented, together with a practical example of its engineering application in superheated steam temperature control with single-stage attemperation in a power plant boiler. This method can remarkably improve the control performance of superheated steam temperature and makes it possible for one stage attemperation to be sufficient for the superheater of power plant boilers, thus simplifying the superheater system and reducing investment. Because the control performance is remarkably raised, the set values of the steam temperature control system can be raised above rated values and also the operational economy, without impairing the operation safety.

  12. Thickness of compound layer in steel-aluminum solid to liquid bonding

    Institute of Scientific and Technical Information of China (English)

    Peng Zhang; Yunhui Du; Hanwu Liu; Shuming Xing; Daben Zeng; Jianzhong Cui; Limin Ba

    2003-01-01

    The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The surface of solid steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. In order to determine the thickness of Fe-A1 compound layer at the interface of steel-aluminum solid to liquid bonding under rapid solidification, the interface of bonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationship between bonding parameters (such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time) and thickness of Fe-Al compound layer at the interface was established by artificial neural networks (ANN) perfectly. The maximum of relative error between the output and the desired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacial shear strength of bonding plate (226℃ for preheat temperature of steel plate, 723 ℃ for temperature of aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-A1 compound layer 10.8 μm was got.

  13. A 3D Computational Study on the Air-Blast Atomization of a Planar Liquid Layer

    Science.gov (United States)

    Chiodi, Robert; Desjardins, Olivier

    2016-11-01

    The air-blast atomization of a planar liquid layer is a complex fluid phenomenon involving the destabilization of a low speed liquid layer by a high speed gas coflow. While progress has been made in recent years on understanding the instability of the liquid surface, it remains difficult to accurately predict using stability analysis and requires special expertise and equipment to perform thorough experiments. Simulations provide an excellent way to conduct parametric studies to determine the effect of splitter plate geometry and momentum flux ratio on the frequency and wavelengths of instability, however, they are extremely difficult due to the high density ratio and large range of length and time scales present in the flow. Using an accurate conservative level set method in conjunction with a newly reformulated reinitialization equation, we perform 3D simulations of the air-blast atomization of a planar liquid layer and compare them to experiments. We then go on to explore the role momentum flux ratio plays in the longitudinal and transverse wavelengths of instability.

  14. Development of a Parching Machine Using Super-Heated Vapor or Super-Heated High-Moisture Atmosphere

    Science.gov (United States)

    Sato, Shoichi; Shinsho, Seiji; Iriki, Hiroyuki; Asai, Junya; Suganuma, Hirofumi; Shibata, Tsutomu

    We developed a new parching machine with super-heated vapor or super-heated highmoisture atmosphere as a heat medium, and investigated the influence exerted on the characteristics of manufactured tea and crude tea quality. (1)We developed machine specifications that improved throughput and allowed us to control stable quality compared with the conventional kamairicha parching machine. (2)The new parching machine could not only manufacture like kamairicha but also achieve various degrees of steaming of products like green tea or heavily steamed sencha. (3)The new parching machine could not only deactivate enzymes but dry leaves. (4)The influence of throughput was great with respect to the grade of pan-parched flavour, which meant that there was a contact opportunity for tea leaves and the surface of machine's wall. (5)Unpleasant smells such as that produced in a summer crop of tea were reduced by the new parching machine.

  15. Comparison of liquid-liquid extraction-thin layer chromatography with solid-phase extraction-high-performance thin layer chromatography in detection of urinary morphine.

    Science.gov (United States)

    Ahadi, Ali; Partoazar, Alireza; Abedi-Khorasgani, Mohammad-Hassan; Shetab-Boushehri, Seyed Vahid

    2011-09-01

    Liquid-liquid extraction-thin layer chromatography (LLE-TLC) has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction (SPE) is gradually replacing the traditional LLE method. High performance thin layer chromatography (HPTLC) has several advantages over TLC. The present work studied the higher efficiency of a new SPE-HPTLC method over that of a routine LLE-TLC method, in extraction and detection of urinary morphine. Fifty-eight urine samples, primarily identified as morphine-positive samples by a strip test, were re-screened by LLE-TLC and SPE-HPTLC. The results of LLE-TLC and SPE-HPTLC were then compared with each other. The results showed that the SPE-HPTLC detected 74% of total samples as morphine-positive samples whereas the LLE-TLC detected 48% of the same samples. We further discussed the effect of codeine abuse on TLC analysis of urinary morphine. Regarding the importance of morphine detection in urine, the present combined SPE-HPTLC method is suggested as a replacement method for detection of urinary morphine by many reference laboratories.

  16. Transient temperature of liquid on micro metal layer heated by pulsed laser

    Science.gov (United States)

    Li, Ji; Zhang, Zhengfang; Liu, Dengying

    1999-06-01

    In this paper the transient temperature of liquid on micro metal layer heated by pulsed high energy laser is simulated by numerical method, especially around the theoretical homogeneous boiling point(THBP). The relationship between temperature rising rate and laser fluence is obtained; and under different temperature rising rate the distributions of temperature in liquid and metal around the THBP are obtained. With numerical simulation the relation between the temperature rising rate and laser parameters (fluence and pulse width) is known and so in the future the rapid transient boiling phenomenon could be studied and analyzed.

  17. Transient Temperature of Liquid on Micro Metal Layer Heated by Pulsed Laser

    Institute of Scientific and Technical Information of China (English)

    LiJi; ZhangZhengfangtffu

    1999-01-01

    In this paper the transient temperature of liquid on micro metal layer heated by pulsed high energy laser is simulated by numerical method ,especially around the theoretical homogeneous boiling point (THBP),The relationship between temperature rising rate and laser fluence is obtained;and under different temperature rising rate the distributions of temperature in liquid and metal around the THBP are obtained.With numerical simulation the relation between the temperature rising rate and laser parameters(fluence and pulse width)is known and so in the future the rapid transient boiling phenomenon could be studed and analyzed.

  18. Ultrasound-based measurement of liquid-layer thickness: A novel time-domain approach

    Science.gov (United States)

    Praher, Bernhard; Steinbichler, Georg

    2017-01-01

    Measuring the thickness of a thin liquid layer between two solid materials is important when the adequate separation of metallic parts by a lubricant film (e.g., in bearings or mechanical seals) is to be assessed. The challenge in using ultrasound-based systems for such measurements is that the signal from the liquid layer is a superposition of multiple reflections. We have developed an algorithm for reconstructing this superimposed signal in the time domain. By comparing simulated and measured signals, the time-of-flight of the ultrasonic pulse in a layer can be estimated. With the longitudinal sound velocity known, the layer thickness can then be calculated. In laboratory measurements, we validate successfully (maximum relative error 4.9%) our algorithm for layer thicknesses ranging from 30 μm to 200 μm. Furthermore, we tested our method in the high-temperature environment of polymer processing by measuring the clearance between screw and barrel in the plasticisation unit of an injection moulding machine. The results of such measurements can indicate (i) the wear status of the tribo-mechanical screw-barrel system and (ii) unsuitable process conditions.

  19. Electric-field variations within a nematic-liquid-crystal layer.

    Science.gov (United States)

    Cummings, L J; Mema, E; Cai, C; Kondic, L

    2014-07-01

    A thin layer of nematic liquid crystal (NLC) across which an electric field is applied is a setup of great industrial importance in liquid crystal display devices. There is thus a large literature modeling this situation and related scenarios. A commonly used assumption is that an electric field generated by electrodes at the two bounding surfaces of the layer will produce a field that is uniform: that is, the presence of NLC does not affect the electric field. In this paper, we use calculus of variations to derive the equations coupling the electric potential to the orientation of the NLC's director field, and use a simple one-dimensional model to investigate the limitations of the uniform field assumption in the case of a steady applied field. The extension of the model to the unsteady case is also briefly discussed.

  20. Solid Catalyst with Ionic Liquid Layer (SCILL). A concept to improve the selectivity of selective hydrogenations

    Energy Technology Data Exchange (ETDEWEB)

    Jess, A.; Korth, W. [Bayreuth Univ. (Germany). Chair of Chemical Engineering

    2011-07-01

    Catalytic hydrogenations are important for refinery processes, petrochemical applications as well as for numerous processes of the fine chemicals industry. In some cases, hydrogenations consist of a sequence of consecutive reactions, and the desired product is the intermediate. An important goal is then a high yield and selectivity to the intermediate, if possible at a high conversion degree. The selectivity to an intermediate primarily depends on the chemical nature of the catalyst, but may also be influenced by diffusion processes. Ionic liquids (ILs) are low melting salts (< 100 C) and represent a promising solvent class. This paper focuses on the concept of a Solid Catalyst with Ionic Liquid Layer (SCILL), where the solid catalyst is coated with a thin IL layer to improve the selectivity. (orig.)

  1. Liquid Crystal Alignment Control Using Polymer Filament and Polymer Layers Coated on Substrates

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2005-04-01

    We investigated liquid crystal (LC) alignment in LC cells containing an aligned cellulose filament sandwiched by thin polymer layers coated on substrates. Three types of polymer material, namely polystyrene (PS), polyvinyl alcohol (PVA) and polyimide (PI), were used as polymer layers. LC alignment areas induced on both sides of the filament were large in the order of PS, PVA and PI. In the case of the PS layer, the average LC alignment area reached approximately 100 μm in the direction perpendicular to the polymer filament. The molecular interaction between the LC and the PS layer is thought to be weak and it does not disturb the LC alignment due to the polymer filament. On the other hand, rubbed PS layers were used as polymer layers of the LC cell, where the LC alignment direction induced by the rubbed PS layer was perpendicular to the polymer filament. It was found that the LC alignment near the polymer filament gradually bent in the cell plane. The result suggests that various three-dimensional LC alignments can be realized by the combination of the polymer filament and substrate surface.

  2. Order parameters of liquid crystal on the rubbing surfaces of alignment layers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Liquid crystal (LC) alignment is most important in LC devices. In this paper, we quantitatively analyze the LC scalar order parameters on the rubbed surface of an alignment layer. Careful measurement of dichroic infrared absorbance is performed. The result gives the evidence that the order parameter of LC just on the rubbed alignment film is only 1/3-1/2 that in the LC bulk.

  3. Coherent random lasing from liquid waveguide gain layer containing silica nanoparticles

    Science.gov (United States)

    Ye, Lihua; Feng, Yangyang; Lu, Changgui; Hu, Guohua; Cui, Yiping

    2016-10-01

    A unidirectional coherent random laser is constructed by a sandwich structure consisting of two polydimethylsiloxane plates and a highly transparent ultra-thin liquid active layer embedded with silica nanoparticles (NPs). The optical feedback of the random laser is provided by both strong waveguide confinement and the SiO2 NPs’ multiple scattering. Compared with random laser in a quartz cuvette, the pump threshold is only 700 µJ cm-2. The lowest threshold is obtained in an optimum concentration of silica NPs. The change of peak positions in the liquid waveguide structure is larger than that in the quartz cuvette for different solvents. The peak-shift of the emission wavelength is more sensitive in the liquid waveguide structure, which is a promising platform for bio-chemical and bio-sensing applications.

  4. Production method of raw material dispersion liquid for reaction layer of gas diffusion electrode

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Choichi; Motoo, Satoshi

    1987-10-13

    Heretofore, in order to make a raw material dispersion liquid of a reaction layer of a gas diffusion electrode, water repellent carbon, polytetrafluoroethylene, water and a surface active agent are mixed, then a cake is made by filtering this mixed liquid and afterwards the cake is heated and dried before being crushed. Since this crushing is done mechanically, homogeneous fine raw material powders cannot be obtained. Accordingly, even when a reaction layer is made by sintering a mixture of this powder, hydrophilic carbon black or hydrophilic carbon black carrying catalyst, and polytetrafluoroethylene, the hydrophilic part and the water repellent part are not distributed homogeneously and the catalytic performance of the reaction layer declines. In order to solve this, this invention proposes a production method that water repellent carbon black, polyterafluoroethylene, water and a surface active agent are mixed, then this mixture is frozen so that the surface active agent may not become active and homogeneous condensed cores of water repellent carbon black and polytetrafluoroethylene powders may be formed, and afterwards a homogeneous fine raw material dispersion liquid is made from thawing the condensed cores without change by thawing the above frozen mixture.

  5. Effects of porosity distribution variation on the liquid water flux through gas diffusion layers of PEM fuel cells

    Science.gov (United States)

    Zhan, Zhigang; Xiao, Jinsheng; Li, Dayong; Pan, Mu; Yuan, Runzhang

    Flooding of the membrane electrode assembly (MEA) and dehydrating of the polymer electrolyte membrane have been the key problems to be solved for polymer electrolyte membrane fuel cells (PEMFCs). So far, almost no papers published have focused on studies of the liquid water flux through differently structured gas diffusion layers (GDLs). For gas diffusion layers including structures of uniform porosity, changes in porosity (GDL with microporous layer (MPL)) and gradient change porosity, using a one-dimensional model, the liquid saturation distribution is analyzed based on the assumption of a fixed liquid water flux through the GDL. And then the liquid water flux through the GDL is calculated based on the assumption of a fixed liquid saturation difference between the interfaces of the catalyst layer/GDL and the GDL/gas channel. Our results show that under steady-state conditions, the liquid water flux through the GDL increases as contact angle and porosity increase and as the GDL thickness decreases. When a MPL is placed between the catalyst layer and the GDL, the liquid saturation is redistributed across the MPL and GDL. This improves the liquid water draining performance. The liquid water flux through the GDL increases as the MPL porosity increases and the MPL thickness decreases. When the total thickness of the GDL and MPL is kept constant and when the MPL is thinned to 3 μm, the liquid water flux increases considerably, i.e. flooding of MEA is difficult. A GDL with a gradient of porosity is more favorable for liquid water discharge from catalyst layer into the gas channel; for the GDLs with the same equivalent porosity, the larger the gradient is, the more easily the liquid water is discharged. Of the computed cases, a GDL with a linear porosity 0.4 x + 0.4 is the best.

  6. Visualization of boundary-layer development on turbomachine blades with liquid crystals

    Science.gov (United States)

    Vanzante, Dale E.; Okiishi, Theodore H.

    1991-01-01

    This report documents a study of the use of liquid crystals to visualize boundary layer development on a turbomachine blade. A turbine blade model in a linear cascade of blades was used for the tests involved. Details of the boundary layer development on the suction surface of the turbine blade model were known from previous research. Temperature sensitive and shear sensitive liquid crystals were tried as visual agents. The temperature sensitive crystals were very effective in their ability to display the location of boundary layer flow separation and reattachment. Visualization of natural transition from laminar to turbulent boundary layer flow with the temperature sensitive crystals was possible but subtle. The visualization of separated flow reattachment with the shear sensitive crystals was easily accomplished when the crystals were allowed to make a transition from the focal-conic to a Grandjean texture. Visualization of flow reattachment based on the selective reflection properties of shear sensitive crystals was achieved only marginally because of the larger surface shear stress and shear stress gradient levels required for more dramatic color differences.

  7. First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility

    Science.gov (United States)

    Olson, R. E.; Leeper, R. J.; Kline, J. L.; Zylstra, A. B.; Yi, S. A.; Biener, J.; Braun, T.; Kozioziemski, B. J.; Sater, J. D.; Bradley, P. A.; Peterson, R. R.; Haines, B. M.; Yin, L.; Berzak Hopkins, L. F.; Meezan, N. B.; Walters, C.; Biener, M. M.; Kong, C.; Crippen, J. W.; Kyrala, G. A.; Shah, R. C.; Herrmann, H. W.; Wilson, D. C.; Hamza, A. V.; Nikroo, A.; Batha, S. H.

    2016-12-01

    The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D2 and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (12 NIF utilized high convergence (CR >30 ) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

  8. Liquid/liquid interface layering of 1-butanol and [bmim]PF6 ionic liquid: a nonlinear vibrational spectroscopy and molecular dynamics simulation study.

    Science.gov (United States)

    Iwahashi, Takashi; Ishiyama, Tatsuya; Sakai, Yasunari; Morita, Akihiro; Kim, Doseok; Ouchi, Yukio

    2015-10-14

    IR-visible sum-frequency generation (IV-SFG) vibrational spectroscopy and a molecular dynamics (MD) simulation were used to study the local layering order at the interface of 1-butanol-d9 and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6), a room-temperature ionic liquid (RTIL). The presence of a local non-polar layer at the interface of the two polar liquids was successfully demonstrated. In the SFG spectra of 1-butanol-d9, we observed significant reduction and enhancement in the strength of the CD3 symmetric stretching (r(+)) mode and the antisymmetric stretching (r(-)) mode peaks, respectively. The results can be well explained by the presence of an oppositely oriented quasi-bilayer structure of butanol molecules, where the bottom layer is strongly bound by hydrogen-bonding with the PF6(-) anion. MD simulations reveal that the hydrogen-bonding of butanol with the PF6(-) anion causes the preferential orientation of the butanols; the restriction on the rotational distribution of the terminal methyl group along their C3 axis enhances the r(-) mode. As for the [bmim](+) cations, the SFG spectra taken within the CH stretch region indicate that the butyl chain of [bmim](+) points away from the bulk RTIL phase to the butanol phase at the interface. Combining the SFG spectroscopy and MD simulation results, we propose an interfacial model structure of layering, in which the butyl chains of the butanol molecules form a non-polar interfacial layer with the butyl chains of the [bmim](+) cations at the interface.

  9. Asymptotic approach in the limit of small contact angles to sessile vapor bubble growth in a superheated environment

    Science.gov (United States)

    Rednikov, Alexey; Hollander, Nicolas; Hernando Revilla, Marta; Colinet, Pierre

    2014-11-01

    A model of nucleate pool boiling is considered, and more concretely the growth dynamics of a single spherical-cap vapor bubble on a flat superheated substrate in a large volume of an equally superheated liquid. An asymptotic scheme is developed valid in the limit of small contact angles. These are basically supposed to be the evaporation-induced ones and hence finite even in the case of a perfectly wetting liquid implied here. The consideration generally involves four regions: i) microregion, where the contact line singularities are resolved and the evaporation-induced contact angles are established, ii) Cox-Voinov region, iii) foot of the bubble, and iv) macroregion. It is only in the latter region, which remarkably appears to leading order in the form of the exterior of a sphere touching a planar surface in one point (hence a fixed geometry even for variable contact angles), that the full Navier-Stokes and heat equations are to be (numerically) resolved. ESA & BELSPO PRODEX, F.R.S.-FNRS.

  10. Liquid-phase-deposited siloxane-based capping layers for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Veith-Wolf, Boris [Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal (Germany); Wang, Jianhui; Hannu-Kuure, Milja; Chen, Ning; Hadzic, Admir; Williams, Paul; Leivo, Jarkko; Karkkainen, Ari [Optitune International Pte. Ltd., 20 Maxwell Road, #05-08 Maxwell House, Singapore 069113 (Singapore); Schmidt, Jan [Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal (Germany); Department of Solar Energy, Institute of Solid-State Physics, Leibniz University Hanover, Appelstrasse 2, 30167 Hanover (Germany)

    2015-02-02

    We apply non-vacuum processing to deposit dielectric capping layers on top of ultrathin atomic-layer-deposited aluminum oxide (AlO{sub x}) films, used for the rear surface passivation of high-efficiency crystalline silicon solar cells. We examine various siloxane-based liquid-phase-deposited (LPD) materials. Our optimized AlO{sub x}/LPD stacks show an excellent thermal and chemical stability against aluminum metal paste, as demonstrated by measured surface recombination velocities below 10 cm/s on 1.3 Ωcm p-type silicon wafers after firing in a belt-line furnace with screen-printed aluminum paste on top. Implementation of the optimized LPD layers into an industrial-type screen-printing solar cell process results in energy conversion efficiencies of up to 19.8% on p-type Czochralski silicon.

  11. In-Plane Switching Mode for Liquid Crystal Displays Using a DNA Alignment Layer.

    Science.gov (United States)

    Cha, Yun Jeong; Gim, Min-Jun; Oh, Kyunghwan; Yoon, Dong Ki

    2015-06-24

    We successfully fabricated the in-plane switching mode (IPS) LC display (LCD) based on a double stranded DNA (dsDNA) alignment layer. As widely known, the DNA has the right-handed double helical structure that has naturally grown grooves with a very regular period, which can be used as an alignment layer to control the orientation of liquid crystal (LC) molecules. The LC molecules on this topographical layer of DNA material align obliquely at a specific angle with respect to the direction of DNA chains, providing an instant and convenient tool for the fabrication of the IPS display compared to the conventional ways such as rubbing and mechanical shearing methods. The electro-optical performance and response time of this device were also investigated. Our result will be of great use in further exploration of the electro-optical properties of the other biomaterials.

  12. Double layers liquid-crystal microlens arrays used in optical switches

    Science.gov (United States)

    Wang, Cheng; Fan, Di; Zhang, Bo; Tong, Qing; Luo, Jun; Lei, Yu; Zhang, Xinyu; Xie, Changsheng

    2015-12-01

    Based on our previous works in liquid-crystal microlens arrays (LCMAs), a new kind of optical switches using the 24×24 fiber arrays coupled with the LCMAs, which have a key dual-mode function of the switches about on and off state and work in visible and infrared range, is proposed and fabricated in this paper. Different with other common LCMAs, this new kind of dual-mode LCMAs includes two layers of control electrodes deposited directly over the surface of the top glass substrate in LC microcavity fabricated. The first layer is the patterned electrode, which is designed into basic circular holes with suitable diameter, and the second is the planar electrode. Both layered electrodes are effectively separated by a thin SiO2 film with a typical thickness of about several micrometers, and then the dual-mode microlenses are driven by applied electrical signals with different root mean square (rms) voltage.

  13. A high-resolution tracking hodoscope based on capillary layers filled with liquid scintillator

    CERN Document Server

    Bay, A; Bruski, N; Buontempo, S; Currat, C; D'Ambrosio, N; Ekimov, A V; Ereditato, A; Fabre, Jean-Paul; Fanti, V; Frekers, D; Frenkel, A; Golovkin, S V; Govorun, V N; Harrison, K; Koppenburg, P; Kozarenko, E N; Kreslo, I E; Liberti, B; Martellotti, G; Medvedkov, A M; Mondardini, M R; Penso, G; Siegmund, W P; Vasilchenko, V G; Vilain, P; Wilquet, G; Winter, Klaus; Wörtche, H J

    2001-01-01

    Results are given on tests of a high-resolution tracking hodoscope based on layers of \\hbox{26-$\\mu$m-bore} glass capillaries filled with organic liquid scintillator (1-methylnaphthalene doped with R39). The detector prototype consisted of three 2-mm-thick parallel layers, with surface areas of $2.1 \\times 21$~cm$^2$. The layers had a centre-to-centre spacing of 6~mm, and were read by an optoelectronic chain comprising two electrostatically focused image intensifiers and an Electron-Bombarded Charge-Coupled Device (EBCCD). Tracks of cosmic-ray particles were recorded and analysed. The observed hit density was 6.6~hits/mm for particles crossing the layers perpendicularly, at a distance of 1~cm from the capillaries' readout end, and 4.2~hits/mm for particles at a distance of 20~cm. A track segment reconstructed in a single layer had an rms residual of $\\sim$~20~$\\mu$m, and allowed determination of the track position in a neighbouring layer with a precision of $\\sim$~170~$\\mu$m. This latter value corresponded to...

  14. Effects of superheated steam on the drying of rubberwood

    Directory of Open Access Journals (Sweden)

    Kanokwan Buaphud

    2006-07-01

    Full Text Available Rubberwood drying is the most time and energy consuming step in the processing of wood product. This research studied the effect of superheated steam drying on the drying time required and the physical and mechanical properties of rubberwood after drying. In this study, a cylindrical drying chamber with a length of 1.2 m and a diameter of 0.5 m was constructed and injected with superheated steam. The dimensions of the wood lumber were 1 m × 7.62 cm × 2.54 cm. The wood samples were impinged with alternating cycles of superheated steam and hot air at ratios of 6:1, 4:1 and 1:6 hours until the moisture content was less than 15% dry basis. The conditions inside the chamber were 110ºC and ambient pressure. Continuous superheated steam and continuous hot air were also used for comparisons. The drying rate and the temperature profile for each process were determined.Initial acceptability of the dried wood was conducted using the prong test and visual inspection. Results showed that if the drying rate was too fast, the dried wood did not pass the prong test due to stress buildup. Therefore, an optimum drying condition was developed based on minimizing defects and reducing the drying time. For the optimum condition, the following schedule was carried out: (1 saturated steam at 100ºC was used during the first 4 hours of drying to prevent the wood surface from drying too quickly which would minimize the moisture gradient between the center and wood surface, (2 superheated steam at 105ºC and 110ºC was used in alternating cycle with hot air (80ºC during the main drying stages to rapidly remove the free water and majority of the bound water inside the wood, and (3 hot air was used continuously during the final stages of drying to reduce the relative humidity inside the chamber making it possible for the removal of the residual bound water. This process successfully reduced the drying time to less than 2 days without causing any defects which compared

  15. Numerical Modeling of Thermocapillary Deformation and Film Breakdown in a Locally Heated Thin Horizontal Volatile Liquid Layer

    Directory of Open Access Journals (Sweden)

    Barakhovskaya Ella

    2016-01-01

    Full Text Available The problem of thermocapillary deformation and film breakdown in a thin horizontal layer of viscous incompressible liquid with a free surface is considered. The deformable liquid layer is locally heated. The problem of thermocapillary deformation of the locally heated horizontal liquid layer has been solved numerically for two-dimensional unsteady case. The lubrication approximation theory is used. Capillary pressure, viscosity and gravity are taken into account. Evaporating rate is supposed to be proportional to the temperature difference between the liquid and ambient. Heat transfer in the substrate is also simulated. The numerical algorithm for the joint solution of the energy equation and the evolution equation for the thickness of liquid layer has been developed. The model predicts the thermocapillary deformation of the liquid surface and the formation of dry spots. The dynamics of liquid surface, the dry spots formation and the velocity of the contact line have been calculated. The deformation of the free surface has been calculated for different values of the heating power and thickness of the liquid layer. The effect of surface tension coefficient and wetting contact angle on the velocity of the contact line motion has been analyzed. It has been obtained that the velocity of the contact line increases with the increase of the wetting contact angle value and of the surface tension coefficient.

  16. Applicability of superheated drop (bubble) detectors to reactor dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    d`Errico, F.; Curzio, G. [Univ. degli Studi di Pisa (Italy). Dipt. di Costruzioni Meccaniche e Nucleari; Alberts, W.G. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Apfel, R.E.; Guldbakke, S. [Yale Univ., New Haven, CT (United States). Dept. of Mechanical Engineering

    1994-12-31

    The characteristics of superheated drop (bubble) detectors (SDD`s) have been reviewed with respect to the possible application of these devices in reactor dosimetry. In particular, their ability to measure neutrons in the presence of a high noise level, elevated temperatures and intense {gamma} background has been investigated. Based on these studies, the use of SDD`s is proposed for the monitoring and analysis of neutron emission from spent fuel assemblies. Finally, the possibility to employ these detectors in radiation protection dosimetry around power plants is discussed.

  17. Design and Study of Multifarious Plans on Superheated Steam Saturator%过热蒸汽饱和器的多种方案设计研究

    Institute of Scientific and Technical Information of China (English)

    周根明; 程颖

    2011-01-01

    本文基于传热传质基本原理,提出了一种过热蒸汽饱和器,可将换热设备中的过热蒸汽转化成饱和蒸汽.并详细介绍没计了3种供液方案--重力水箱式、文丘里管式和泵式装置,使之满足不同用户的多种需要.%Based on the principle of heat and mass exchange , a type of superheated steam saturator is designed. The superheated steam could be saturated by the saturator. Three plans of feed liquid equipments are described in detail, and the style contains gravity water tank、Venturi tube pattern and pump form. It would be satisfied by the multiple demands of many consumers.

  18. Osmotic pressure of ionic liquids in an electric double layer: Prediction based on a continuum model.

    Science.gov (United States)

    Moon, Gi Jong; Ahn, Myung Mo; Kang, In Seok

    2015-12-01

    An analysis has been performed for the osmotic pressure of ionic liquids in the electric double layer (EDL). By using the electromechanical approach, we first derive a differential equation that is valid for computing the osmotic pressure in the continuum limit of any incompressible fluid in EDL. Then a specific model for ionic liquids proposed by Bazant et al. [M. Z. Bazant, B. D. Storey, and A. A. Kornyshev, Phys. Rev. Lett. 106, 046102 (2011)] is adopted for more detailed computation of the osmotic pressure. Ionic liquids are characterized by the correlation and the steric effects of ions and their effects are analyzed. In the low voltage cases, the correlation effect is dominant and the problem becomes linear. For this low voltage limit, a closed form formula is derived for predicting the osmotic pressure in EDL with no overlapping. It is found that the osmotic pressure decreases as the correlation effect increases. The osmotic pressures at the nanoslit surface and nanoslit centerline are also obtained for the low voltage limit. For the cases of moderately high voltage with high correlation factor, approximate formulas are derived for estimating osmotic pressure values based on the concept of a condensed layer near the electrode. In order to corroborate the results predicted by analytical studies, the full nonlinear model has been solved numerically.

  19. Probing Photochemistry in the Quasi-Liquid Layer: Laboratory Studies and Implications for OASIS Processes

    Science.gov (United States)

    Mahanna, K. M.; Greis, V.; Grannas, A. M.

    2005-12-01

    Recent studies illustrate the previously overlooked importance of snow and ice as reactive chemical media in the environment. It has been shown that the Arctic snowpack plays an important role in processing atmospheric species such as mercury, nitrogen oxides, alkyl halides, ozone, carbonyl compounds and molecular halogens. Photochemical transformations of anthropogenic organic contaminants in ice also have been observed, although published information regarding these processes is scant. It has been shown that a liquid-like (quasi-liquid or disordered) layer exists on the surface of pure ice and that a quasi-liquid layer (QLL) is also found on the surface of ambient snow crystals and ice at temperatures relevant to polar conditions. It is unclear what role the QLL on the surface of snow/ice plays in potential photochemical reactions. Here we report results of recent laboratory studies of photochemistry occurring in the QLL. We used the well characterized reaction of p-nitroanisole with pyridine to probe changes in photochemistry that may occur upon freezing. We found that freezing greatly enhanced the rate of this particular reaction (the half-life of the reaction was 20 times shorter when the solution was frozen). Additionally, we could alter the half-life in predictable ways by changing variables such as ionic strength and temperature. The findings of these experiments will be discussed as well as the potential implications to ocean-air-sea ice-snow (OASIS) interactions of organic pollutants in polar climates.

  20. Stability of an unsupported multi-layer surfactant laden liquid curtain under gravity

    KAUST Repository

    Henry, D.

    2015-11-07

    The industrial process of curtain coating has long been an important method in coating applications, by which a thin liquid curtain is formed to impinge upon a moving substrate, due to its highly lucrative advantage of being able to coat multiple layers simultaneously. We investigate the linear stability of an unsupported two-layer liquid curtain, which has insoluble surfactants in both liquids, which are widely used in industry to increase the stability of the curtain. We formulate the governing equations, simplified by making a thin film approximation, from which we obtain equations describing the steady-state profiles. We then examine the response of the curtain to small perturbations about this steady state to identify conditions under which the curtain is unstable, finding the addition of surfactants stabilizes the curtain. Our results are then compared to experimental data, showing a favourable trend and thereby extending the works of Brown (J Fluid Mech 10:297–305, 1960) and Dyson et al. (J Eng Math 64:237–250, 2009).

  1. Locomotion of bacteria in liquid flow and the boundary layer effect on bacterial attachment

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao, E-mail: zhangchao@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China); Liao, Qiang, E-mail: lqzx@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China); Chen, Rong, E-mail: rchen@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China); Zhu, Xun, E-mail: zhuxun@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030 (China); Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030 (China)

    2015-06-12

    The formation of biofilm greatly affects the performance of biological reactors, which highly depends on bacterial swimming and attachment that usually takes place in liquid flow. Therefore, bacterial swimming and attachment on flat and circular surfaces with the consideration of flow was studied experimentally. Besides, a mathematical model comprehensively combining bacterial swimming and motion with flow is proposed for the simulation of bacterial locomotion and attachment in flow. Both experimental and theoretical results revealed that attached bacteria density increases with decreasing boundary layer thickness on both flat and circular surfaces, the consequence of which is inherently related to the competition between bacterial swimming and the non-slip motion with flow evaluated by the Péclet number. In the boundary layer, where the Péclet number is relatively higher, bacterial locomotion mainly depends on bacterial swimming. Thinner boundary layer promotes bacterial swimming towards the surface, leading to higher attachment density. To enhance the performance of biofilm reactors, it is effective to reduce the boundary layer thickness on desired surfaces. - Highlights: • Study of bacterial locomotion in flow as an early stage in biofilm formation. • Mathematical model combining bacterial swimming and the motion with flow. • Boundary layer plays a key role in bacterial attachment under flow condition. • The competition between bacterial swimming and the motion with flow is evaluated.

  2. Electrohydrodynamic instability in an annular liquid layer with radial conductivity gradients.

    Science.gov (United States)

    Ding, Zijing; Wong, Teck Neng

    2014-03-01

    In this paper, the electrohydrodynamic stability in an annular liquid layer with a radial electrical conductivity gradient is investigated. A weak shear flow arises from a constant pressure gradient in the axial direction. In the radial direction, an electric field is applied. The three-dimensional linear instability analysis is implemented to study the influence of the inner radius, electrical conductivity gradient, shear flow, and ionic diffusion on the dynamics of the fluid layer. It is found that the critical unstable mode may either be oscillatory or stationary. The system becomes more unstable as the dimensionless inner radius a increases. When the inner radius a is small, the critical unstable mode is stationary, while it is given by three-dimensional oblique waves when a is large. When the conductivity gradient is small, the critical unstable mode is the three-dimensional oblique wave, while when the conductivity gradient is large, it would switch to the stationary mode rather than the oscillatory mode. The system becomes more unstable when the Reynolds number is slightly increased from zero. Additionally, it is found that the electrical Schmidt number has dual effects. The liquid layer becomes either more unstable or stable as the electric Schmidt number increases.

  3. Superheated Water-Cooled Small Modular Underwater Reactor Concept

    Directory of Open Access Journals (Sweden)

    Koroush Shirvan

    2016-12-01

    Full Text Available A novel fully passive small modular superheated water reactor (SWR for underwater deployment is designed to produce 160 MWe with steam at 500ºC to increase the thermodynamic efficiency compared with standard light water reactors. The SWR design is based on a conceptual 400-MWe integral SWR using the internally and externally cooled annular fuel (IXAF. The coolant boils in the external channels throughout the core to approximately the same quality as a conventional boiling water reactor and then the steam, instead of exiting the reactor pressure vessel, turns around and flows downward in the central channel of some IXAF fuel rods within each assembly and then flows upward through the rest of the IXAF pins in the assembly and exits the reactor pressure vessel as superheated steam. In this study, new cladding material to withstand high temperature steam in addition to the fuel mechanical and safety behavior is investigated. The steam temperature was found to depend on the thermal and mechanical characteristics of the fuel. The SWR showed a very different transient behavior compared with a boiling water reactor. The inter-play between the inner and outer channels of the IXAF was mainly beneficial except in the case of sudden reactivity insertion transients where additional control consideration is required.

  4. Fundamental Properties of Superheated Drop (Bubble) Detectors (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    D' Errico, F

    1999-07-01

    Superheated drop detectors and bubble damage detectors find increasing applications in ionising radiation dosimetry and spectrometry. These emulsions of overexpanded halocarbon droplets can be manufactured to respond selectively to densely ionising particles, such as neutron recoils, or to all directly and indirectly ionising radiations. It is shown here that the fundamental properties of the detectors can be predicted by semi-empirical expressions based on the thermal spike theory. A new non-dimensional quantity, defined as 'reduced superheat', is introduced and shown to permit a unified parametrisation of the properties of superheated emulsions. In particular, utilising the reduced superheat concept, it is possible to predict the neutron detection thresholds of the emulsions, their sensitisation to thermal neutrons and to photons, and their ultimate thermodynamic instability. This unified characterisation finds immediate application in the selection of the halocarbons and of the operating conditions most suitable for specific radiation detection problems. Finally, some data are presented which question a direct proportionality between the particle track length contributing to the vaporisation and a critical bubble diameter derived from spontaneous nucleation models. An effective track length based on experimental observations is introduced to derive the minimum track-averaged LET for bubble nucleation expressed as a function of reduced superheat. (author)

  5. Parametric excitation of oscillatory Marangoni instability in a heated liquid layer covered by insoluble surfactant

    Science.gov (United States)

    Mikishev, Alexander B.; Nepomnyashchy, Alexander A.

    2017-04-01

    This paper is a continuation of our previous research reported in the two last IMA conferences. While in our previous works the driving modulation was a modulation of the temperature gradient, here the temperature gradient is fixed in the whole liquid layer and the liquid is vertically vibrated with some fixed driving frequency. Two kinds of waves can be generated in this system. The first kind of waves are transverse (capillary-gravity) waves. The second kind of waves are longitudinal (Marangoni) waves caused by the dependence of the surface tension on the temperature and the surfactant concentration. A linear analysis with arbitrary wave numbers is performed. Two different heating regimes were considered. Multiple instability regions depending on the heating conditions are analyzed. Among three possible modes of the system's response to external forcing, the most "dangerous" one is the subharmonic instability mode.

  6. Analysis of the Pressure Rise in a Partially Filled Liquid Tank in Microgravity with Low Wall Heat Flux and Simultaneous Boiling and Condensation

    Science.gov (United States)

    Hasan, Mohammad M.; Balasubramaniam, R.

    2012-01-01

    Experiments performed with Freon 113 in the space shuttle have shown that in a pro- cess of very slow heating, high liquid superheats can be sustained for a long period in microgravity. In a closed system explosive vaporization of superheated liquid resulted in pressure spikes of varying magnitudes. In this paper, we analyze the pressure rise in a partially lled closed tank in which a large vapor bubble (i.e., ullage) is initially present, and the liquid is subjected to a low wall heat ux. The liquid layer adjacent to the wall becomes superheated until the temperature for nucleation of the bubbles (or the incipience of boiling) is achieved. In the absence of the gravity-induced convection large quantities of superheated liquid can accumulate over time near the heated surface. Once the incipience temperature is attained, explosive boiling occurs and the vapor bubbles that are produced on the heater surface tend to quickly raise the tank pressure. The liquid-vapor saturation temperature increases as well. These two e ects tend to induce condensation of the large ullage bubble that is initially present, and tends to mitigate the tank pressure rise. As a result, the tank pressure is predicted to rise sharply, attain a maximum, and subsequently decay slowly. The predicted pressure rise is compared with experimental results obtained in the microgravity environments of the space shuttle for Freon 113. The analysis is appli- cable, in general to heating of liquid in closed containers in microgravity and to cryogenic fuel tanks, in particular where small heat leaks into the tank are unavoidable.

  7. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mroczek, Tomasz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland)]. E-mail: tmroczek@pharmacognosy.org; Ndjoko-Ioset, Karine [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland); Glowniak, Kazimierz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Mietkiewicz-Capala, Agnieszka [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Hostettmann, Kurt [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland)

    2006-05-04

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C{sub 18} column using a gradient elution. Based on MS {sup n} spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide.

  8. Influence of Elemental Iron on Hydrogen Content in Superheated Aluminum-iron Melts

    Institute of Scientific and Technical Information of China (English)

    HU Li-na; BIAN Xiu-fang; ANANDA Mahto; DUAN You-feng

    2004-01-01

    The hydrogen content in liquid binary aluminum alloys with 1,3,5 and 8 wt% iron has been determined in the temperature range from 973K to 1103K.The hydrogen content in molten Al-Fe alloys increases remarkably when the temperature of the melt rises to about 1053K.This work indicates that the alloying element iron plays an important role in hydrogen content in superheated Al-Fe alloy melts below about 1053K.The results make it clear that the hydrogen content in the melt aluminum reduces with the increasing element levels.A conclusion is drawn that the degree of gassing in molten Al-Fe alloys is bound up with the properties of oxide film of aluminum alloy melts.The element iron has no effect on the compact structure of oxide film in aluminum melts.The effects of alloying element are theoretically analyzed in terms of Wagner interaction parameter.According to the values of the first order interaction parameter,it is concluded that the interaction between iron atom and aluminum is much stronger than that between hydrogen atom and aluminum,and the addition of the alloying element decreases the affinity of liquid aluminum for hydrogen.

  9. Condensation on Highly Superheated Surfaces: Unstable Thin Films in a Wickless Heat Pipe.

    Science.gov (United States)

    Kundan, Akshay; Nguyen, Thao T T; Plawsky, Joel L; Wayner, Peter C; Chao, David F; Sicker, Ronald J

    2017-03-03

    A wickless heat pipe was operated on the International Space Station to provide a better understanding of how the microgravity environment might alter the physical and interfacial forces driving evaporation and condensation. Traditional heat pipes are divided into three zones: evaporation at the heated end, condensation at the cooled end, and intermediate or adiabatic in between. The microgravity experiments reported herein show that the situation may be dramatically more complicated. Beyond a threshold heat input, there was a transition from evaporation at the heated end to large-scale condensation, even as surface temperatures exceeded the boiling point by 160 K. The hotter the surface, the more vapor was condensed onto it. The condensation process at the heated end is initiated by thickness and temperature disturbances in the thin liquid film that wet the solid surface. Those disturbances effectively leave the vapor "superheated" in that region. Condensation is amplified and sustained by the high Marangoni stresses that exist near the heater and that drive liquid to cooler regions of the device.

  10. A new method of immobilizing ionic liquids into layered zirconium phosphates

    Institute of Scientific and Technical Information of China (English)

    Hai Yan Wang; Da Xiong Han

    2007-01-01

    In this work, a new method of a series of ion liquids (ILs) l-alkyl-3-methylimidazolium chloride [Cnmim]Cl (n = 2, 4, 6, 8) intercalation into layered zirconium phosphates was investigated.It was found that the α-ZrP-2BA (i.e.pre-intercalated BA was arranged in a bilayer mode in the galleries ofα-ZrP) was a suitable host for intercalation ILs: ILs was inserted through exchanging pre-intercalated BA.And the intercalation orientation was investigated by use of X-ray diffraction (XRD) experiments and molecular modeling calculation.

  11. Investigations and experiments of a new multi-layer complex liquid-cooled mirror

    Institute of Scientific and Technical Information of China (English)

    Yuling Lu(陆宇灵); Zuhai Cheng(程祖海); Yaoning Zhang(张耀宁); Feng Sun(孙锋); Wenfeng Yu(余文峰)

    2004-01-01

    This paper describes a new multi-layer complex liquid-cooled Si mirror with 3 cooling ducts in Archimedes spirals. Utilizing the ANSYS program, the structure of the mirror is optimized and the thermal deformation model of the mirror is simulated. The simulation results show that the mirror has the following advantages:very small amount of surface deformation, uniform distribution of temperature and surface deformation,and fast surface shape restoration. The results of the experiments of thermal deformation and the surface restoration are accurately mapped to the simulation results.

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

    Science.gov (United States)

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

    2016-09-01

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

  13. Molecular field theory for nematic liquid crystal film with finite layers

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhi-Dong; Li Jing; Wei Huai-Peng

    2005-01-01

    The nematic liquid crystal film composed of n molecular layers is studied based upon a spatially anisotropic pair potential, which reproduces approximately the elastic free energy density. On condition that the system has perfect nematic order, as in the Lebwohl-Lasher model, the director in the film is isotropic. The effect of the temperature is investigated by means of molecular field theory. Some new results are obtained. Firstly, symmetry breaking takes place when taking account of the temperature, and the state with the director along the normal of the film has the lowest free energy. Secondly, the N-I phase transition temperature increases as an effect of finite sizes instead of decreasing as in the Lebwohl-Lasher model. Thirdly, the nematic order is induced in the layers near the surface in the isotropic phase.

  14. Evaluation of molecular dynamics simulation methods for ionic liquid electric double layers

    Science.gov (United States)

    Haskins, Justin B.; Lawson, John W.

    2016-05-01

    We investigate how systematically increasing the accuracy of various molecular dynamics modeling techniques influences the structure and capacitance of ionic liquid electric double layers (EDLs). The techniques probed concern long-range electrostatic interactions, electrode charging (constant charge versus constant potential conditions), and electrolyte polarizability. Our simulations are performed on a quasi-two-dimensional, or slab-like, model capacitor, which is composed of a polarizable ionic liquid electrolyte, [EMIM][BF4], interfaced between two graphite electrodes. To ensure an accurate representation of EDL differential capacitance, we derive new fluctuation formulas that resolve the differential capacitance as a function of electrode charge or electrode potential. The magnitude of differential capacitance shows sensitivity to different long-range electrostatic summation techniques, while the shape of differential capacitance is affected by charging technique and the polarizability of the electrolyte. For long-range summation techniques, errors in magnitude can be mitigated by employing two-dimensional or corrected three dimensional electrostatic summations, which led to electric fields that conform to those of a classical electrostatic parallel plate capacitor. With respect to charging, the changes in shape are a result of ions in the Stern layer (i.e., ions at the electrode surface) having a higher electrostatic affinity to constant potential electrodes than to constant charge electrodes. For electrolyte polarizability, shape changes originate from induced dipoles that soften the interaction of Stern layer ions with the electrode. The softening is traced to ion correlations vertical to the electrode surface that induce dipoles that oppose double layer formation. In general, our analysis indicates an accuracy dependent differential capacitance profile that transitions from the characteristic camel shape with coarser representations to a more diffuse

  15. Weakly doped InP layers prepared by liquid phase epitaxy using a modulated cooling rate

    Science.gov (United States)

    Krukovskyi, R.; Mykhashchuk, Y.; Kost, Y.; Krukovskyi, S.; Saldan, I.

    2017-04-01

    Epitaxial structures based on InP are widely used to manufacture a number of devices such as microwave transistors, light-emitting diodes, lasers and Gunn diodes. However, their temporary instability caused by heterogeneity of resistivity along the layer thickness and the influence of various external or internal factors prompts the need for the development of a new reliable technology for their preparation. Weak doping by Yb, Al and Sn together with modulation of the cooling rate applied to prepare InP epitaxial layers is suggested to be adopted within the liquid phase epitaxy (LPE) method. The experimental results confirm the optimized conditions created to get a uniform electron concentration in the active n-InP layer. A sharp profile of electron concentration in the n+-InP(substrate)/n-InP/n+-InP epitaxial structure was observed experimentally at the proposed modulated cooling rate of 0.3 °С-1.5 °С min-1. The proposed technological method can be used to control the electrical and physical properties of InP epitaxial layers to be used in Gunn diodes.

  16. Laboratory Research of the Two-Layer Liquid Dynamics at the Wind Surge in a Strait Canal

    Directory of Open Access Journals (Sweden)

    S.F. Dotsenko

    2017-06-01

    Full Text Available The results of laboratory experiments in a straight aerohydrocanal of the rectangular cross-section filled with the two-layer (fresh-salty liquid are represented. The disturbance generator is the air flow directed to the area above the canal. The cases of the two-layer liquid dynamics in the canal with the horizontal flat bottom and in the presence of the bottom obstacle of finite width are considered. It is shown that during the surge in the straight canal, one of the possible exchange mechanisms on the boundary of fresh and salty layers may consist in the salt water emissions (resulted from the Kelvin-Helmholtz instability to the upper freshwater layer. The subsequent eviction can possibly be accompanied by occurrence of undulations at the interface. Besides, the evictions can be followed by formation of the oscillating layer, i.e. the layer with maximum density gradient the oscillations of which propagate to the overlying layers. Presence of the bottom obstacle complicates the structure of the two-layer liquid motions. In particular, it results in emergence of the mixed layers and transformation of the flow behind the obstacle into a turbulent one, formation of the wave-like disturbances over the obstacle, sharp change of the interface position and occurrence of large-scale vortices with the horizontal axes. It is revealed that the maximum peak of the flow velocity horizontal component is shifted upstream from the obstacle.

  17. Diagnostics of boundary layer transition by shear stress sensitive liquid crystals

    Science.gov (United States)

    Shapoval, E. S.

    2016-10-01

    Previous research indicates that the problem of boundary layer transition visualization on metal models in wind tunnels (WT) which is a fundamental question in experimental aerodynamics is not solved yet. In TsAGI together with Khristianovich Institute of Theoretical and Applied Mechanics (ITAM) a method of shear stress sensitive liquid crystals (LC) which allows flow visualization was proposed. This method allows testing several flow conditions in one wind tunnel run and does not need covering the investigated model with any special heat-insulating coating which spoils the model geometry. This coating is easily applied on the model surface by spray or even by brush. Its' thickness is about 40 micrometers and it does not spoil the surface quality. At first the coating obtains some definite color. Under shear stress the LC coating changes color and this change is proportional to shear stress. The whole process can be visually observed and during the tests it is recorded by camera. The findings of the research showed that it is possible to visualize boundary layer transition, flow separation, shock waves and the flow image on the whole. It is possible to predict that the proposed method of shear stress sensitive liquid crystals is a promise for future research.

  18. Phase transition time delays in irradiated superheated superconducting granules

    CERN Document Server

    Abplanalp, M; Czapek, G; Diggelmann, U; Furlan, M; Gabutti, A; Janos, S; Moser, U; Pozzi, R; Pretzl, Klaus P; Schmiemann, K; Perret-Gallix, D; Van den Brandt, B; Konter, J A; Mango, S

    1994-01-01

    The time difference between a particle interaction in a Superheated Superconducting Granule (SSG) and the resulting phase transition signal has been explored. Detectors containing Zn and Sn SSG were irradiated with neutrons and protons to study the heating mechanism taking place in nuclear recoil and ionizing events. Scattered neutrons have been detected by a scintillator hodoscope behind the SSG with a recoil energy measurement resolution of 10\\% and an interaction time resolution of 1ns. The fast transition of the metastable granules allowed to determine the elapsed time between an energy deposition and the phase transition signal. In the case of Sn granules, the results show that the time distributions are narrow and independent of the deposited energy in nuclear recoil and ionizing events. In Zn, however, the time distributions are much broader and depend on the energy deposition in the granule.

  19. Aquathermolysis of conventional heavy oil with superheated steam

    Institute of Scientific and Technical Information of China (English)

    Song Guangshou; Zhou Tiyao; Cheng Linsong; Wang Yunxian; Tian Guoqing; Pi Jian; Zhang Zheng

    2009-01-01

    This paper presents a new aquathermolysis study of conventional heavy oil in superheated steam. A new high temperature autoclave was designed, where volume and pressure could be adjusted. Aquathermolysis was studied on two different conventional heavy oil samples under different reaction times and temperatures. Experimental results show that aquathermolysis does take place for conventional heavy oil. As reaction time increases, the oil viscosity reduces. However, the reaction will reach equilibrium after a certain period of time and won't be sensitive to any further reaction time any more. Analysis shows that, while resin and asphaltenes decrease, saturated hydrocarbons and the H/C ratio increase after reaction. The main mechanism of aquathermolysis includes hydrogenization, desulfuration reaction of resin and asphaltenes, etc.

  20. Neutron ambient dosimetry with superheated drop (bubble) detectors

    Energy Technology Data Exchange (ETDEWEB)

    d`Errico, F.; Noccioni, P. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari; Alberts, W.G.; Dietz, E.; Siebert, B.R.L. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Gualdrini, G. [ENEA, Bologna (Italy); Kurkdjian, J. [CEA Centre d`Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Inst. de Protection et de Surete Nucleaire

    1996-12-31

    A prototype neutron area monitor was developed which improves the performance of superheated drop detectors based on halocarbon-12. The detectors are thermally controlled: this removes external temperature effects while ensuring a dose equivalent response optimised with respect to its energy dependence. The system was first characterised through calibrations with monoenergetic neutron beams. In the intermediate energy range, where experimental investigations were not possible, Monte Carlo response calculations were carried out. The prototype was then extensively tested by means of simulated and in-field irradiations with broad neutron spectra. All these tests indicated a remarkably constant dose equivalent response regardless of the neutron energy distributions. The current device is a fairly delicate system which can be operated reliably when environmental conditions are not extreme. Nevertheless, when it was possible to employ it, this monitor demonstrated an accuracy far superior to that of conventional meters used in routine surveillance. (author).

  1. Thermal activation of superheated lipid-coated perfluorocarbon drops.

    Science.gov (United States)

    Mountford, Paul A; Thomas, Alec N; Borden, Mark A

    2015-04-28

    This study explored the thermal conditions necessary for the vaporization of superheated perfluorocarbon nanodrops. Droplets C3F8 and C4F10 coated with a homologous series of saturated diacylphosphatidylcholines were formed by condensation of 4 μm diameter microbubbles. These drops were stable at room temperature and atmospheric pressure, but they vaporized back into microbubbles at higher temperatures. The vaporization transition was measured as a function of temperature by laser light extinction. We found that C3F8 and C4F10 drops experienced 90% vaporization at 40 and 75 °C, respectively, near the theoretical superheat limits (80-90% of the critical temperature). We therefore conclude that the metastabilty of these phase-change agents arises not from the droplet Laplace pressure altering the boiling point, as previously reported, but from the metastability of the pure superheated fluid to homogeneous nucleation. The rate of C4F10 drop vaporization was quantified at temperatures ranging from 55 to 75 °C, and an apparent activation energy barrier was calculated from an Arrhenius plot. Interestingly, the activation energy increased linearly with acyl chain length from C14 to C20, indicating that lipid interchain cohesion plays an important role in suppressing the vaporization rate. The vaporized drops (microbubbles) were found to be unstable to dissolution at high temperatures, particularly for C14 and C16. However, proper choice of the fluorocarbon and lipid species provided a nanoemulsion that could undergo at least ten reversible condensation/vaporization cycles. The vaporization properties presented in this study may facilitate the engineering of tunable phase-shift particles for diagnostic imaging, targeted drug delivery, tissue ablation, and other applications.

  2. Conjugated liquid layers driven by the short-wavelength B\\'enard-Marangoni instability: experiment and numerical simulation

    CERN Document Server

    Nejati, Iman; Hardt, Steffen

    2016-01-01

    The coupled dynamics of two conjugated liquid layers of disparate thicknesses, which coat a solid substrate and are subjected to a transverse temperature gradient, is investigated. The upper liquid layer evolves under the short-wavelength (SW) B\\'enard-Marangoni (BM) instability, whereas the lower, much thinner film undergoes a shear-driven long-wavelength deformation. Although the lubricating film should reduce the viscous stresses acting on the up to one hundred times thicker upper layer by only 10%, it is found that the critical Marangoni number of marginal stability may be as low as if a stress-free boundary condition were applied at the bottom of the upper layer, i.e. much lower than the classical value of 79.6 known for a single film. Furthermore, it is experimentally verified that the deformation of the liquid-liquid interface, albeit small, has a non-negligible effect on the temperature distribution along the liquid-gas interface of the upper layer. This stabilizes the hexagonal pattern symmetry towar...

  3. Investigation of coherent structures in a superheated jet using decomposition methods

    Science.gov (United States)

    Sinha, Avick; Gopalakrishnan, Shivasubramanian; Balasubramanian, Sridhar

    2016-11-01

    A superheated turbulent jet, commonly encountered in many engineering flows, is complex two phase mixture of liquid and vapor. The superposition of temporally and spatially evolving coherent vortical motions, known as coherent structures (CS), govern the dynamics of such a jet. Both POD and DMD are employed to analyze such vortical motions. PIV data is used in conjunction with the decomposition methods to analyze the CS in the flow. The experiments were conducted using water emanating into a tank containing homogeneous fluid at ambient condition. Three inlet pressure were employed in the study, all at a fixed inlet temperature. 90% of the total kinetic energy in the mean flow is contained within the first five modes. The scatterplot for any two POD coefficients predominantly showed a circular distribution, representing a strong connection between the two modes. We speculate that the velocity and vorticity contours of spatial POD basis functions show presence of K-H instability in the flow. From DMD, eigenvalues away from the origin is observed for all the cases indicating the presence of a non-oscillatory structure. Spatial structures are also obtained from DMD. The authors are grateful to Confederation of Indian Industry and General Electric India Pvt. Ltd. for partial funding of this project.

  4. Towards understanding the structure and capacitance of electrical double layer in ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, Maxim V. [Max Planck Institute for Mathematics in the Sciences, D 04103 Leipzig (Germany); Unilever Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Kornyshev, Alexei A. [Department of Chemistry, Faculty of Natural Sciences, Imperial College London, SW7 2AZ London (United Kingdom)

    2008-10-01

    In order to understand basic principles of the double layer formation in room temperature ionic liquids, we have performed Molecular Dynamic simulations for a simplified system: dense assembly of charged Lennard-Jones spheres between charged walls. For simplicity, in this first investigation we have considered the cations and anions of the same size. We have calculated the corresponding values of the double layer capacitance as a function of the electrode potential and compared the results with existing theories. We have found that the capacitance curve does not follow the U-shape of the Gouy-Chapman theory, but has a bell-shape in agreement with the mean-field theory that takes into account the effect of limited maximum packing of ions. The wings of capacitance decrease inversely proportional to the square root of the electrode potential, as prescribed by the mean-field theory and the charge conservation law at large electrode polarizations. We have found, however, that the mean-field theory does not quantitatively reproduce the simulation results at small electrode potentials, having detected their remarkable overscreening effects (ionic correlations). The plots for the distributions of ions near the electrode at different electrode charges show that for the considered system, unlike it is often assumed, the double layer is not one layer thick. The overscreening effects, dominating near the potential of zero charge (p.z.c.), are suppressed by the high electrode polarizations, following the onset of the so-called 'lattice saturation effect'. The maximum of the capacitance coincides with the p.z.c., but it is true only for this 'symmetric' system. If sizes of cations and anions are different the maximum will be shifted away from the p.z.c., and generally the shape of the capacitance curve could be more complicated. (author)

  5. Thermal effect on gravity waves in a compressible liquid layer over a solid half-space under initial hydrostatic stress

    Indian Academy of Sciences (India)

    Sushil Kumar Addy; Nil Ratan Chakraborty

    2005-02-01

    This paper deals with the effect of temperature on gravity waves in a compressible liquid layer over a solid half-space. It has been assumed that the liquid layer is under the action of gravity, while the solid half-space is under the influence of initial compressive hydrostatic stress. When the temperature of the half-space is altered, gravity waves propagate through the liquid layer along with sub-oceanic Rayleigh waves in the system. A new frequency equation has been derived here for gravity waves and sub-oceanic Rayleigh waves. It has been shown graphically that the phase velocity of gravity waves is influenced significantly by the initial compressive hydrostatic stress present in the solid half-space, for a particular value of the phase velocity of sub-oceanic Rayleigh waves and different coupling co-efficients of the temperature.

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

    KAUST Repository

    Vakarelski, Ivan Uriev

    2016-09-08

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

  7. Flexo- and piezo-electric polarization of smectic layers in ferroelectric and antiferroelectric liquid crystals

    Science.gov (United States)

    Kuczyński, W.; Hoffmann, J.; Dardas, D.; Nowicka, K.; Bielejewska, N.

    2015-11-01

    In this paper, we report on how flexoelectric and piezoelectric polarization components can be determined by a method based on simultaneous studies of dielectric and electrooptic properties of the chiral smectic liquid crystal in the regime of weak electric fields. As a rule, the measurements of spontaneous polarization are performed using switching experiments. The polarization measured in this way is not complete—it contains the piezoelectric component only. However, the knowledge of the entire local polarization of a single smectic layer is of great importance—it is necessary for correct determination of some material parameters, for instance elastic constants. Our experiments performed in a helical smectic mixture demonstrated that flexoelectric contribution to the local spontaneous polarization is significant in both ferroelectric and antiferroelectric phases. In the antiferroelectric phase, the flexoelectric polarization is less due to higher helical pitch.

  8. Time-frequency analysis for ultrasonic measurement of liquid-layer thickness

    Science.gov (United States)

    Jiao, Jingpin; Liu, Wenhua; Zhang, Jie; Zhang, Qiang; He, Cunfu; Wu, Bin

    2013-02-01

    Lubricant film thickness is one of the most important parameters to indicate the operating condition of machine elements, such as mechanical seals and hydrostatic slideway. When ultrasonic waves illuminate the interfaces between the substrates and a lubricant film, it will be reflected due to the change of the material properties at the interfaces. These reflected ultrasonic waves contain information about film thickness. In this paper, wavelet transform modulus maximum method was explored to extract the film thickness from its reflection ultrasonic signals. The performance of different wavelet functions within various scale factors was experimentally investigated, and the optimal wavelet function with the optimal scale factor was pointed out. It has been shown that the measurement error is less than 5% when the thickness of liquid layer is within a certain range.

  9. Coupling of Evaporation and Thermocapillary Convection in a Liquid Layer with Mass and Heat Exchanging Interface

    Institute of Scientific and Technical Information of China (English)

    JI Yan; LIU Qiu-Sheng; LIU Rong

    2008-01-01

    We propose and analyse a new model of thermocapillary convection with evaporation in a cavity subjected to horizontal temperature gradient.rather than the previously studied model without evaporation.The pure liquid layer with a top free surface in contact with its own vapour is considered in microgravity condition.The computing programme developed for simulating this model integrates the two-dimensional,time-dependent Navier-Stokes equationsand energy equation bya second-order accurate projection method.We focus on the coupling of evaporation and thermocapillary convection by investigating the influence of evaporation Biot number and Marangoni number on the interfacial mass and heat transfer.Thtee different regimes of the coupling mechanisms are found and explained from our numerical results.

  10. Mixtures of room temperature ionic liquid/ethanol solutions as electrolytic media for cerium oxide thin layer electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Lair, V., E-mail: virginie-lair@chimie-paristech.f [Laboratoire d' Electrochimie, Chimie des Interfaces et Modelisation pour l' Energie, LECIME, CNRS UMR 7575-Chimie Paristech (ENSCP)-Paris, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Sirieix-Plenet, J.; Gaillon, L.; Rizzi, C. [UPMC University Paris 06, UMR 7195, Laboratoire de Physicochimie des Electrolytes, Colloides et Sciences Analytiques (PECSA), F-75005 Paris (France); CNRS, UMR 7195, PECSA, F-75005 Paris (France); ESPCI, UMR 7195, PECSA, F-75005 Paris (France); Ringuede, A. [Laboratoire d' Electrochimie, Chimie des Interfaces et Modelisation pour l' Energie, LECIME, CNRS UMR 7575-Chimie Paristech (ENSCP)-Paris, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France)

    2010-12-30

    A cerium oxide thin layer was electrodeposited onto stainless steel, using mixed room temperature ionic liquid (the 1-methyl-3-butylimidazolium bis(trifluoromethyl sulfonyl)imide)/ethanol solutions, as electrolytic medium. The hydrophobic ionic liquid content is one of the main parameters in the morphology control influencing the ceria growth rate and crystallinity. Micro-nano structural properties and electrical behaviour are presented, using XRD, SEM/EDS and impedance spectroscopy, as a function of electrodeposition conditions.

  11. Molecular dynamics simulation studies of ionic liquid electrolytes for electric double layer capacitors

    Science.gov (United States)

    Hu, Zongzhi

    Molecular Dynamics (MD) simulation has been performed on various Electric Double Layer Capacitors (EDLCs) systems with different Room Temperature Ionic Liquids (RTILs) as well as different structures and materials of electrodes using a computationally efficient, low cost, united atom (UA)/explicit atom (EA) force filed. MD simulation studies on two 1-butyl-3-methylimidazolium (BMIM) based RTILs, i.e., [BMIM][BF4] and [BMIM][PF6], have been conducted on both atomic flat and corrugated graphite as well as (001) and (011) gold electrode surfaces to understand the correlations between the Electric Double Layer (EDL) structure and their corresponding differential capacitance (DC). Our MD simulations have strong agreement with some experimental data. The structures of electrodes also have a strong effect on the capacitance of EDLCs. MD simulations have been conducted on RTILs of N-methyl-N- propylpyrrolidinium [pyr13] and bis(fluorosulfonyl)imide (FSI) as well as [BMIM][PF6] on both curvature electrodes (fullerenes, nanotube, nanowire) and atomic flat electrode surfaces. It turns out that the nanowire electrode systems have the largest capacitance, following by fullerene systems. Nanotube electrode systems have the smallest capacitance, but they are still larger than that of atomically flat electrode system. Also, RTILs with slightly different chemical structure such as [Cnmim], n = 2, 4, 6, and 8, FSI and bis(trifluoromethylsulfonyl)imide (TFSI), have been examined by MD simulation on both flat and nonflat graphite electrode surfaces to study the effect of cation and anion's chemical structures on EDL structure and DC. With prismatic (nonflat) graphite electrodes, a transition from a bell-shape to a camel-shape DC dependence on electrode potential was observed with increase of the cation alkyl tail length for FSI systems. In contrast, the [Cnmim][TFSI] ionic liquids generated only a camel-shape DC on the rough surface regardless of the length of alkyl tail.

  12. Study of gamma ray response of R404A superheated droplet detector using a two-state model

    CERN Document Server

    Mondal, P K

    2013-01-01

    The superheated droplet detector (SDD) is known to be gamma insensitive below a threshold temperature which made them excellent candidates for neutron detection in the presence of gamma rays. Above the threshold temperature, the gamma ray detection efficiency increases with increase in temperature. In this work the gamma ray threshold temperature has been studied for SDD using R404A as the active liquid and is compared to the theoretical prediction. The temperature variation of gamma ray detection efficiency and interstate transition kinetics has also been studied using a two-state model. The experiments are performed at the ambient pressure of 1 atmosphere and in the temperature range of 17-32oC using a 662 keV 137Cs gamma ray source.

  13. Neutron reflectivity as method to study in-situ adsorption of phospholipid layers to solid-liquid interfaces

    DEFF Research Database (Denmark)

    Gutberlet, Thomas; Klösgen, Beate Maria; Krastev, Rumen

    2004-01-01

    The use of neutron reflectivity as a method to study in-situ adsorption of phospholipid layers to solid-liquid interfaces was analyzed. The most important advantage of neutron reflectometry is the possibility to very the refractive index of the specific sample by isotope exchange, called contrast...... variation. It was observed that the method was capable of visualizing the adsorption of phospholipid layers to different solid-liquid interfaces and to resolve structural details at Angstroem resolution. The results depended strongly on a sufficiently good signal-to-noise ratio of the specific measurements...

  14. Controlling the Spatial Organization of Liquid Crystalline Nanoparticles by Composition of the Organic Grafting Layer.

    Science.gov (United States)

    Wójcik, Michał M; Olesińska, Magdalena; Sawczyk, Michał; Mieczkowski, Józef; Górecka, Ewa

    2015-07-01

    Understanding how the spatial ordering of liquid crystalline nanoparticles can be controlled by different factors is of great importance in the further development of their photonic applications. In this paper, we report a new key parameter to control the mesogenic behavior of gold nanoparticles modified by rodlike thiols. An efficient method to control the spatial arrangement of hybrid nanoparticles in a condensed state is developed by changing the composition of the mesogenic grafting layer on the surface of the nanoparticles. The composition can be tuned by different conditions of the ligand exchange reaction. The thermal and optical behavior of the mesogenic and promesogenic ligands were investigated by using differential scanning calorimetry (DSC) and hot-stage polarized optical microscopy. The chemical structure of the synthesized hybrid nanoparticles was characterized by (1) H NMR spectroscopy, thermogravimetric analysis (TGA), XPS, and elemental analysis, whereas the superstructures were examined by small-angle X-ray diffraction (SAXSRD) analysis. Structural studies showed that the organic sublayer made of mesogenic ligands is denser with an increasing the average ligand number, thereby separating the nanoparticles in the liquid crystalline phases, which changes the parameters of these phases.

  15. Acousto-optic effect in a nematic liquid-crystal layer under the binary effect of sound and viscous waves

    Energy Technology Data Exchange (ETDEWEB)

    Kozhevnikov, E. N., E-mail: kozhev@ssu.samara.ru [Samara State University (Russian Federation)

    2010-03-15

    The optical effect in a liquid crystal cell containing a homeotropic layer of nematic liquid crystal (NLC) is analyzed. An NLC layer, located between crossed polaroids and opaque in the absence of external effect, is cleared after irradiation by an ultrasonic beam with a sharp spatial boundary. This enlightenment is suggested to be caused by the reorientation of crystal molecules in the acoustic flows that arise under the binary effect of the layer compression in the irradiated region and the viscous waves propagating from the layer boundaries. The flows were calculated taking into account the stress caused by the velocity convection and crystal structure relaxation. An expression is derived for the cell transparency, and the relative role of the convection and relaxation processes in the effect is determined.

  16. Numerical investigation of heat and mass transfer processes in a spherical layer of viscous incompressible liquid with free boundaries

    Directory of Open Access Journals (Sweden)

    Zakurdaeva Alia

    2016-01-01

    Full Text Available The results of mathematical modelling of the dynamics of a mixture of the viscous incompressible liquid and gas, which fills a spherical layer with free boundaries and contains a gas bubble within itself, are presented in this paper. Spherical symmetry is assumed, and it is considered that the dynamics of the layer is determined by thermal, diffusive and inertial factors. On the basis of constructed numerical algorithm the studies of the formation of the liquid glass layers, which contain the carbon dioxide gas within themselves, have been conducted. The impact of the external thermal regime, external pressure and the density of gas in the bubble at the initial time on the dynamics of the layer, diffusion and heat-and-mass processes inside it is investigated. The results of numerical investigation of the full and simplified thermal problem statement, without consideration of gas diffusion, are compared.

  17. Velocity fields of a bed-load layer under a turbulent liquid flow

    CERN Document Server

    Penteado, Marcos Roberto Mendes

    2016-01-01

    The transport of sediments by a fluid flow is commonly found in nature and in industry. In nature, it is found in rivers, oceans, deserts, and other environments. In industry, it is found in petroleum pipelines conveying grains, in sewer systems, and in dredging lines, for example. This study investigates experimentally the transport of the grains of a granular bed sheared by a turbulent liquid flow. In our experiments, fully developed turbulent water flows were imposed over a flat granular bed of known granulometry. Under the tested conditions, the grains were transported as bed load, i.e., they became entrained by rolling and sliding over each other, forming a moving granular layer. The present experiments were performed close to incipient bed load, a case for which experimental data on grains velocities are scarce. Distinct from previous experiments, an entrance length assured that the water stream over the loose bed was fully developed. At different water flow rates, the moving layer was filmed using a hi...

  18. The onset of layer undulations in smectic A liquid crystals due to a strong magnetic field

    Science.gov (United States)

    Contreras, A.; Garcia-Azpeitia, C.; García-Cervera, C. J.; Joo, S.

    2016-08-01

    We investigate the effect of a strong magnetic field on a three dimensional smectic A liquid crystal. We identify a critical field above which the uniform layered state loses stability; this is associated to the onset of layer undulations. In a previous work García-Cervera and Joo (2012 Arch. Ration. Mech. Anal. 203 1-43), García-Cervera and Joo considered the two dimensional case and analyzed the transition to the undulated state via a simple bifurcation. In dimension n  =  3 the situation is more delicate because the first eigenvalue of the corresponding linearized problem is not simple. We overcome the difficulties inherent to this higher dimensional setting by identifying the irreducible representations for natural actions on the functional that take into account the invariances of the problem thus allowing for reducing the bifurcation analysis to a subspace with symmetries. We are able to describe at least two bifurcation branches, highlighting the richer landscape of energy critical states in the three dimensional setting. Finally, we analyze a reduced two dimensional problem, assuming the magnetic field is very strong, and are able to relate this to a model in micromagnetics studied in Alouges et al (2002 ESAIM Control Optim. Calc. Var. 8 31-68), from where we deduce the periodicity property of minimizers.

  19. Thermal Performance of Low Layer Density Multilayer Insu1ation Using Liquid Nitrogen

    Science.gov (United States)

    Johnson, Wesley L.; Fesmire, James E.

    2011-01-01

    In order to support long duration cryogenic propellant storage, the Cryogenic Fluid Management (CFM) Project of the Exploration Technology Development Program (ETDP) is investigating the long duration storage propertie$ of liquid methane on the lunar surface. The Methane Lunar Surface Thermal Control (MLSTC) testing is using a tank of the approximate dimensions of the Altair ascent tanks inside of a vacuum chamber to simulate the environment in low earth orbit and on the lunar surface. The thermal performance testing of multilayer insulation (MLI) coupons that are fabricated identically to the tank applied insulation is necessary to understand the performance of the blankets and to be able to predict the performance of the insulation prior to testing. This coupon testing was completed in Cryostat-100 at the Cryogenics Test Laboratory. The results showed the properties of the insulation as a function of layer density, number of layers, and warm boundary temperature. These results aid in the understanding of the performance parameters o fMLI and help to complete the body of literature on the topic.

  20. Study of high gain spherical shell ICF targets containing uniform layers of liquid deuterium tritium fuel. A numericial model for analyzing thermal layering of liquid mixtures of hydrogen isotopes inside a spherical inertial confinement fusion target: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, E.M.; Kim, Kyekyoon [Lawrence Livermore National Lab., CA (United States)

    1994-05-01

    A numerical model has been developed to describe the thermally induced behavior of a liquid layer of hydrogen isotopes inside a spherical Inertial Confinement Fusion (ICF) target and to calculate the far-field temperature gradient which will sustain a uniform liquid layer. This method is much faster than the trial-and-error method previously employed. The governing equations are the equations of continuity, momentum, energy, mass diffusion-convection, and conservation of the individual isotopic species. Ordinary and thermal diffusion equations for the diffusion of fluxes of the species are included. These coupled equations are solved by a finite-difference method using upwind schemes, variable mesh, and rigorous boundary conditions. The solution methodology unique to the present problem is discussed in detail. in particular, the significance of the surface tension gradient driven flows (also called Marangoni flows) in forming uniform liquid layers inside ICF targets is demonstrated. Using the theoretical model, the values of the externally applied thermal gradients that give rise to uniform liquid layers of hydrogen inside a cryogenic spherical-shell ICF target are calculated, and the results compared with the existing experimental data.

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

    Science.gov (United States)

    Wei, Tao; Duan, Fei

    2016-12-01

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

  2. Neutron spectrometry in mixed fields: superheated drop (bubble) detectors.

    Science.gov (United States)

    d'Errico, F; Matzke, M

    2003-01-01

    The BINS neutron threshold spectrometer permits the analysis of the main features of a neutron field for radiation protection purposes. The system offers a virtually complete photon discrimination and nested threshold responses to neutrons, which allow the use of very effective 'few-channel' unfolding procedures. To date, the practical operating energy range of a BINS is 0.1-10 MeV, over which a resolving power of 20-30% can be expected when the deconvolution is performed without explicit pre-information. Spectrum unfolding results in relatively high uncertainties on the differential fluence distributions, but due to negative correlations in adjacent energy groups the uncertainties on integral quantities such as dose equivalent are small and of the order of 5% to 10%, similar to the results of other active spectrometers. In comparison with most radiation detectors, the BINS is an extremely slow system due to the intrinsic duration of a bubble pulse and to the time associated with pulse analysis. For example, the maximum sustainable fluence rate of 1 MeV neutrons is about 10(4) cm(-2) s(-1), which is low for many neutron physics experiments. However, this rate corresponds to an ambient dose equivalent rate of about 1 mSv h(-1), making the active device adequate for radiation protection applications in the workplaces described in Section 1. There are ample margins for improvement of the spectrometer. In particular, in the low-energy region a thermal-epithermal neutron group may be added by using chlorine-bearing emulsions stabilised at suitable temperatures. In fact, the latest version of the system achieves this goal by using a single superheated emulsion of dichlorotetrafluoroethane (R-114) operated at temperatures up to 55 degrees C. This extends the range of the spectrometer and at the same time removes the undue enhancement of the UNFANA output in the low energy region. Above 10 MeV, the resolution can be improved by adding more thresholds, e.g. by starting from

  3. Structure and thermal expansion of liquid bismuth

    Directory of Open Access Journals (Sweden)

    Mudry S.

    2015-12-01

    Full Text Available Experimental structural data for liquid Bi were used for estimation of the main structure parameters as well as the thermal expansion coefficient both in supercooled and superheated temperature ranges. It was shown that the equilibrium melt had a positive thermal expansion coefficient within a temperature range upon melting and a negative one at higher temperatures. The former was related to structure changes upon melting, whereas the latter with topologic disordering upon further heating. It was found that the superheated melt had a negative thermal expansion coefficient. The results obtained from structural data were compared with the thermal expansion coefficient calculated from the data of density for liquid Bi.

  4. Long Term Effects of Multiple DBD Pulses on Thin Liquid Layers Over Tissue: Reactive Fluences and Electric Fields

    Science.gov (United States)

    Tian, Wei; Kushner, Mark J.

    2014-10-01

    Atmospheric dielectric barrier discharges (DBDs) are used in treatment of tissue, often covered by thin liquid layers. The reactivity reaching the tissue depends on the plasma dose, composition and acidification of the liquid, and the cumulative delivery of electric fields through the liquid. In this paper, we report on a computational investigation of the interaction of DBDs with a thin liquid layer covering tissue over many minutes. We used nonPDPSIM, a 2-d model in which Poisson's equation, the electron temperature equation, transport equations for charged and neutral species and radiation transport are solved in both the gas and liquid. The liquid layer, 100's μm thick, is water with dissolved gases [O2aq (aq is aqueous), CO2aq], metal ions (Feaq2+ , Feaq3+) , and organics (RHaq) . Hundreds of pulses at 100 Hz are computed, followed by minutes of afterglow. In the liquid, transient radicals (OHaq, Haq) are produced during the discharge pulse and are consumed during the interpulse period. Terminal species (H2O2aq, O3aq) accumulate and diffuse to the tissue. Ions are dominated by NO3-aq, O2-aq and H3Oaq+.Production of HNO3aq and HOONOaq is assisted by O2aq for the first pulses and then O3aq. Accumulating nitric acid lowers the pH. RHaq consumes most reactive oxygen species in the early plasma treatment leaving Raq. With longer exposure, RHaq can be consumed, enabling more ROS to reach the tissue. The cumulative exposure of electric fields to the tissue depends on the increasing conductivity of the liquid. Work supported by DOE Office of Fusion Energy Science and NSF.

  5. Approximate Analytical Solution for One-Dimensional Solidification Problem of a Finite Superheating Phase Change Material Including the Effects of Wall and Thermal Contact Resistances

    Directory of Open Access Journals (Sweden)

    Hamid El Qarnia

    2012-01-01

    Full Text Available This work reports an analytical solution for the solidification of a superheating phase change material (PCM contained in a rectangular enclosure with a finite height. The analytical solution has been obtained by solving nondimensional energy equations by using the perturbation method for a small perturbation parameter: the Stefan number, ε. This analytical solution, which takes into account the effects of the superheating of PCM, finite height of the enclosure, thickness of the wall, and wall-solid shell interfacial thermal resistances, was expressed in terms of nondimensional temperature distributions of the bottom wall of the enclosure and both PCM phases, and the dimensionless solid-liquid interface position and its dimensionless speed. The developed solution was firstly compared with that existing in the literature for the case of nonsuperheating PCM. The predicted results agreed well with those published in the literature. Next, a parametric study was carried out in order to study the impacts of the dimensionless control parameters on the dimensionless temperature distributions of the wall, the solid shell, and liquid phase of the PCM, as well as the solid-liquid interface position and its dimensionless speed.

  6. Dispersion of Rayleigh, Scholte, Stoneley and Love waves in a model consisting of a liquid layer overlying a two-layer transversely isotropic solid medium

    Science.gov (United States)

    Bagheri, Amirhossein; Greenhalgh, Stewart; Khojasteh, Ali; Rahimian, Mohammad

    2015-10-01

    The dispersion of interface waves is studied theoretically in a model consisting of a liquid layer of finite thickness overlying a transversely isotropic solid layer which is itself underlain by a transversely isotropic solid of dissimilar elastic properties. The method of potential functions and Hankel transformation was utilized to solve the equations of motion. Two frequency equations were developed: one for Love waves and the other for the remaining surface and interface waves. Numerical group and phase velocity dispersion curves were computed for four different classes of model, in which the substratum is stiffer or weaker than the overlying layer, and for various thickness combinations of the layers. Dispersion curves are presented for generalized Rayleigh, Scholte, Stoneley and Love waves, each of which are possible in all proposed models. They show the dependence of the velocity on layer thicknesses and material properties (elastic constants). Special cases involving zero thickness for the water layer or the solid layer, and/or isotropic material properties for the solid exhibit interesting features and agree favourably with previously published results for these simpler cases, thus validating the new formulation.

  7. Issues related to waste sewage sludge drying under superheated steam

    Directory of Open Access Journals (Sweden)

    Hamawand Ihsan

    2015-12-01

    Full Text Available Sewage sludge was dried in a rotary drum dryer under superheated steam. Particle size and moisture content were shown to have significant influences on sticking and agglomeration of the materials. Pouring partially dried sludge (70–80% moisture content, wet basis directly into the screw feeder of the drum dryer resulted in a significant sticking to the surface of the drum and the final particle size of the product was greater than 100 mm in diameter. The moisture content of this product was slightly less than its initial value. To overcome this issue, the sludge was mixed with lignite at variety ratios and then chopped before being introduced to the feeding screw. It was found that mixing the sludge with lignite and then sieving the chopped materials through a four millimetre mesh sieve was the key to solve this issue. This technique significantly reduced both stickiness and agglomeration of the material. Also, this enabled for a significant reduction in moisture content of the final product.

  8. Microwave superheated water extraction of polysaccharides from spent coffee grounds.

    Science.gov (United States)

    Passos, Cláudia P; Coimbra, Manuel A

    2013-04-15

    The spent coffee grounds (SCG) are a food industry by-product that can be used as a rich source of polysaccharides. In the present work, the feasibility of microwave superheated water extraction of polysaccharides from SCG was studied. Different ratios of mass of SCG to water, from 1:30 to 1:5 (g:mL) were used for a total volume of 80 mL. Although the amount of material extracted/batch (MAE1) increased with the increase of the concentration of the sample, the amount of polysaccharides achieved a maximum of 0.57 g/batch for 1:10. Glycosidic-linkage composition showed that all extraction conditions allowed to obtain mainly arabinogalactans. When the unextracted insoluble material was re-extracted under the same conditions (MAE2), a further extraction of polysaccharides was observed (0.34 g/batch for 1:10), mainly galactomannans. Also, a high amount of oligosaccharides, mainly derived from galactomannans, can be obtained in MAE2 (0.96 g/batch for 1:10). This technology allows to obtain galactomannans and arabinogalactans in proportions that are dependent on the operating conditions.

  9. Electronic neutron personal dosimetry with superheated drop detectors

    Energy Technology Data Exchange (ETDEWEB)

    D' Errico, F.; Apfel, R.E.; Curzio, G.; Nath, R

    2001-07-01

    The prototype of an electronic personal neutron dosemeter based on superheated drop detectors is presented. This battery operated device comprises a neutron sensor, bubble-counting electronics and a temperature controller ensuring an optimal dose equivalent response. The neutron sensor is a 12 ml detector vial containing an emulsion of about 50,000 halocarbon-12 droplets of 100 {mu}m diameter. The temperature controller is a low-power, solid-state device stabilising the emulsion at 31.5 deg. C by means of an etched foil heater. The microprocessor-controlled counting electronics relies on a double piezo-electric transducer configuration to record bubble formation acoustically via a comparative pulse-shape analysis of ambient noise and detector signals. The performance of the dosemeter was analysed in terms of the requirements presently developed for neutron personal dosemeters. The detection threshold is about 1 {mu}Sv, while the personal dose equivalent response to neutrons in the thermal to 62 MeV range falls within a factor 1.6 of 13 bubbles per {mu}Sv. (author)

  10. High-energy neutron dosimetry with superheated drop detectors

    Energy Technology Data Exchange (ETDEWEB)

    D' Errico, F.; Agosteo, S.; Sannikov, A.V.; Silari, M

    2002-07-01

    A systematic analysis of the response of dichlorodifluoromethane superheated drop detectors was performed in the 46-133 MeV energy range. Experiments with quasi-monoenergetic neutron beams were performed at the Universite Catholique de Leuvain-la-Neuve, Belgium and the Svedberg Laboratory, Sweden, while tests in a broad field were performed at CERN. To determine the response of the detectors to the high-energy beams, the spectra of incident neutrons were folded over functions modelled after the cross sections for the production of heavy ions from the detector elements. The cross sections for fluorine and chlorine were produced in this work by means of the Monte Carlo high-energy transport code HADRON based on the cascade exciton model of nuclear interactions. The new response data permit the interpretation of measurements at high-energy accelerators and on high-altitude commercial flights, where a 30-50% under-response had been consistently recorded with respect to neutron dose equivalent. The introduction of a 1 cm lead shell around the detectors effectively compensates most of the response defect. (author)

  11. Active neutron spectrometry with superheated drop (bubble) detectors

    Energy Technology Data Exchange (ETDEWEB)

    d`Errico, F.; Curzio, G. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari]|[Istituto Nazionale di Fisica Nucleare, Pisa (Italy); Alberts, W.G.; Guldbakke, S.; Kluge, H.; Matzke, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    1995-12-31

    A new approach to neutron spectrometry has been developed in a joint project by DCMN Pisa and PTB Braunschweig. The system relies on the use of superheated drop (bubble) detectors and the thermodynamic control of their detection thresholds. This is the result of investigations into the physics of these detectors combined with extensive experimental work on their response to neutrons. These studies indicate that the higher the degree of superheat of a detector, the lower the minimum energy that secondary charged particles, and therefore primary neutrons, must impart to the droplets in order to nucleate their evaporation. Therefore, by controlling the temperature of the detectors, accurately defined detection thresholds, virtually any desired one, can be generated in the 0.01-10 MeV neutron energy range. An active prototype instrument has been developed: bubbles are counted acoustically and temperature regulation is achieved by means of thin heating strips. Tests with reference neutron spectra show that the system is suitable for few-channel spectrometry and may be useful for radiation protection dosimetry. Appropriate unfolding algorithms are currently investigated, to be ultimately implemented in an automatic device. (author).

  12. A Theoretical Study of Love Wave Sensors Based on ZnO–Glass Layered Structures for Application to Liquid Environments

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2016-12-01

    Full Text Available The propagation of surface acoustic Love modes along ZnO/glass-based structures was modeled and analysed with the goal of designing a sensor able to detect changes in the environmental parameters, such as liquid viscosity changes and minute amounts of mass supported in the viscous liquid medium. Love mode propagation was modeled by numerically solving the system of coupled electro-mechanical field equations and Navier–Stokes equations. The phase and group velocities and the attenuation of the acoustic wave propagating along the 30° tilted c-axis ZnO/glass structure contacting a viscous non-conductive liquid were calculated for different ZnO guiding layer thicknesses, added mass thicknesses, and liquid viscosity and density. The three sensor responses, i.e., the wave phase and group velocity, and attenuation changes are calculated for different environmental parameters and related to the sensor velocity and attenuation sensitivities. The resulted sensitivities to liquid viscosity and added mass were optimized by adjusting the ZnO guiding layer thickness corresponding to a sensitivity peak. The present analysis is valuable for the manufacture and application of the ZnO-glass structure Love wave sensors for the detection of liquid properties, such as viscosity, density and mass anchored to the sensor surface.

  13. A Theoretical Study of Love Wave Sensors Based on ZnO–Glass Layered Structures for Application to Liquid Environments

    Science.gov (United States)

    Caliendo, Cinzia; Hamidullah, Muhammad

    2016-01-01

    The propagation of surface acoustic Love modes along ZnO/glass-based structures was modeled and analysed with the goal of designing a sensor able to detect changes in the environmental parameters, such as liquid viscosity changes and minute amounts of mass supported in the viscous liquid medium. Love mode propagation was modeled by numerically solving the system of coupled electro-mechanical field equations and Navier–Stokes equations. The phase and group velocities and the attenuation of the acoustic wave propagating along the 30° tilted c-axis ZnO/glass structure contacting a viscous non-conductive liquid were calculated for different ZnO guiding layer thicknesses, added mass thicknesses, and liquid viscosity and density. The three sensor responses, i.e., the wave phase and group velocity, and attenuation changes are calculated for different environmental parameters and related to the sensor velocity and attenuation sensitivities. The resulted sensitivities to liquid viscosity and added mass were optimized by adjusting the ZnO guiding layer thickness corresponding to a sensitivity peak. The present analysis is valuable for the manufacture and application of the ZnO-glass structure Love wave sensors for the detection of liquid properties, such as viscosity, density and mass anchored to the sensor surface. PMID:27918419

  14. A Theoretical Study of Love Wave Sensors Based on ZnO-Glass Layered Structures for Application to Liquid Environments.

    Science.gov (United States)

    Caliendo, Cinzia; Hamidullah, Muhammad

    2016-12-02

    The propagation of surface acoustic Love modes along ZnO/glass-based structures was modeled and analysed with the goal of designing a sensor able to detect changes in the environmental parameters, such as liquid viscosity changes and minute amounts of mass supported in the viscous liquid medium. Love mode propagation was modeled by numerically solving the system of coupled electro-mechanical field equations and Navier-Stokes equations. The phase and group velocities and the attenuation of the acoustic wave propagating along the 30° tilted c-axis ZnO/glass structure contacting a viscous non-conductive liquid were calculated for different ZnO guiding layer thicknesses, added mass thicknesses, and liquid viscosity and density. The three sensor responses, i.e., the wave phase and group velocity, and attenuation changes are calculated for different environmental parameters and related to the sensor velocity and attenuation sensitivities. The resulted sensitivities to liquid viscosity and added mass were optimized by adjusting the ZnO guiding layer thickness corresponding to a sensitivity peak. The present analysis is valuable for the manufacture and application of the ZnO-glass structure Love wave sensors for the detection of liquid properties, such as viscosity, density and mass anchored to the sensor surface.

  15. Self-assembly of colloidal particles in deformation landscapes of electrically driven layer undulations in cholesteric liquid crystals

    Science.gov (United States)

    Varney, Michael C. M.; Zhang, Qiaoxuan; Senyuk, Bohdan; Smalyukh, Ivan I.

    2016-10-01

    We study elastic interactions between colloidal particles and deformation landscapes of undulations in a cholesteric liquid crystal under an electric field applied normal to cholesteric layers. The onset of undulation instability is influenced by the presence of colloidal inclusions and, in turn, layers' undulations mediate the spatial patterning of particle locations. We find that the bending of cholesteric layers around a colloidal particle surface prompts the local nucleation of an undulations lattice at electric fields below the well-defined threshold known for liquid crystals without inclusions, and that the onset of the resulting lattice is locally influenced, both dimensionally and orientationally, by the initial arrangements of colloids defined using laser tweezers. Spherical particles tend to spatially localize in the regions of strong distortions of the cholesteric layers, while colloidal nanowires exhibit an additional preference for multistable alignment offset along various vectors of the undulations lattice. Magnetic rotation of superparamagnetic colloidal particles couples with the locally distorted helical axis and undulating cholesteric layers in a manner that allows for a controlled three-dimensional translation of these particles. These interaction modes lend insight into the physics of liquid crystal structure-colloid elastic interactions, as well as point the way towards guided self-assembly of reconfigurable colloidal composites with potential applications in diffraction optics and photonics.

  16. Effect of titanium oxide compact layer in dye-sensitized solar cell prepared by liquid-phase deposition

    Science.gov (United States)

    Huang, Jung-Jie; Chiu, Shih-Ping; Wu, Menq-Jion; Hsu, Chun-Fa

    2016-11-01

    In this study, titanium dioxide films were deposited on indium tin oxide glass substrates by liquid-phase deposition (LPD) for application as the compact layer in dye-sensitized solar cells (DSSCs). A deposition solution of ammonium hexafluorotitanate and boric acid was used for TiO2 deposition. Compact layer passivation can improve DSSC performance by decreasing carrier losses from recombination at the ITO/electrolyte interface and improving the electrical contact between the ITO and the TiO2 photo-electrode. The optimum thickness of the compact layer was found to be 48 nm, which resulted in a 50 % increase in the conversion efficiency compared with cells without compact layers. The conversion efficiency can be increased from 3.55 to 5.26 %. Therefore, the LPD-TiO2 compact layer inhibits the dark current and increases the short-circuit current density effectively.

  17. Tunable UV-visible absorption of SnS2 layered quantum dots produced by liquid phase exfoliation.

    Science.gov (United States)

    Fu, Xiao; Ilanchezhiyan, P; Mohan Kumar, G; Cho, Hak Dong; Zhang, Lei; Chan, A Sattar; Lee, Dong J; Panin, Gennady N; Kang, Tae Won

    2017-02-02

    4H-SnS2 layered crystals synthesized by a hydrothermal method were used to obtain via liquid phase exfoliation quantum dots (QDs), consisting of a single layer (SLQDs) or multiple layers (MLQDs). Systematic downshift of the peaks in the Raman spectra of crystals with a decrease in size was observed. The bandgap of layered QDs, estimated by UV-visible absorption spectroscopy and the tunneling current measurements using graphene probes, increases from 2.25 eV to 3.50 eV with decreasing size. 2-4 nm SLQDs, which are transparent in the visible region, show selective absorption and photosensitivity at wavelengths in the ultraviolet region of the spectrum while larger MLQDs (5-90 nm) exhibit a broad band absorption in the visible spectral region and the photoresponse under white light. The results show that the layered quantum dots obtained by liquid phase exfoliation exhibit well-controlled and regulated bandgap absorption in a wide tunable wavelength range. These novel layered quantum dots prepared using an inexpensive method of exfoliation and deposition from solution onto various substrates at room temperature can be used to create highly efficient visible-blind ultraviolet photodetectors and multiple bandgap solar cells.

  18. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  19. Light transmission of polymer-dispersed liquid crystal layer composed of droplets with inhomogeneous surface anchoring

    Science.gov (United States)

    Loiko, V. A.; Zyryanov, V. Ya.; Konkolovich, A. V.; Miskevich, A. A.

    2016-01-01

    We have developed a model and realized an algorithm for the calculation of the coefficient of coherent (direct) transmission of light through a layer of liquid crystal (LC) droplets in a polymer matrix. The model is based on the Hulst anomalous diffraction approximation for describing the scattering by an individual particle and the Foldy-Twersky approximation for a coherent field. It allows one to investigate polymer dispersed LC (PDLC) materials with homogeneous and inhomogeneous interphase surface anchoring on the droplet surface. In order to calculate the configuration of the field of the local director in the droplet, the relaxation method of solving the problem of minimization of the free energy volume density has been used. We have verified the model by comparison with experiment under the inverse regime of the ionic modification of the LC-polymer interphase boundary. The model makes it possible to solve problems of optimization of the optical response of PDLC films in relation to their thickness and optical characteristics of the polymer matrix, sizes, polydispersity, concentration, and anisometry parameters of droplets. Based on this model, we have proposed a technique for estimating the size of LC droplets from the data on the dependence of the transmission coefficient on the applied voltage.

  20. Shape-responsive actuator from a single layer of a liquid-crystal polymer.

    Science.gov (United States)

    Kamal, Tahseen; Park, Soo-young

    2014-10-22

    Actuation of various shape changes, including bending, helical twisting, and reversible hinging, has been achieved from a single-layer sheet of poly(1,4-di(4-(3-acryloyloxypropyloxy)benzoyloxy)-2-methylbenzene) [poly(RM257)]. This actuator was developed through photopolymerization of a reactive liquid-crystal (LC) monomer (RM257) mixed with 4-pentyl-4'-cyanobiphenyl (5CB, nematic LC at room temperature) in a planar polyimide-coated LC cell. The UV beam perpendicular to one side of the LC cell produced an asymmetric phase separation between the poly(RM257) network and 5CB that resulted in an asymmetric porous structure along the thickness direction when the 5CB was extracted, in which the UV-exposed surface was pore-free and compact while the opposite surface was highly porous. As a result of this structure, the dry and curled poly(RM257) film exhibits actuation behavior when placed in acetone because of a difference in swelling between the two morphologically different sides, the film UV-exposed and nonexposed sides. The actuation of a three-dimensional tetrahedron (pyramidal) structure is also demonstrated for the first time by using a simple photopatterning technique to selectively control its asymmetric morphology at specific locations.

  1. Mathematical Modeling of Ultra-Superheated Steam Gasification

    Science.gov (United States)

    Xin, Fen

    Pure steam gasification has been of interest in hydrogen production, but with the challenge of supplying heat for endothermic reactions. Traditional solutions included either combusting feedstocks at the price of decreasing carbon conversion ratio, or using costly heating apparatus. Therefore, a distributed gasifier with an Ultra-Superheated-Steam (USS) generator was invented, satisfying the heat requirement and avoiding carbon combustion in steam gasification. This project developed the first version of the Ultra-Superheated-Steam-Fluidization-Model (USSFM V1.0) for the USS gasifier. A stand-alone equilibrium combustion model was firstly developed to calculate the USS mixture, which was the input to the USSFM V1.0. Model development of the USSFM V1.0 included assumptions, governing equations, boundary conditions, supporting equations and iterative schemes of guessed values. There were three nested loops in the dense bed and one loop in the freeboard. The USSFM V1.0 included one main routine and twenty-four subroutines. The USSFM V1.0 was validated with experimental data from the Enercon USS gasifier. The calculated USS mixture had a trace of oxygen, validating the initial expectation of creating an oxygen-free environment in the gasifier. Simulations showed that the USS mixture could satisfy the gasification heat requirement without partial carbon combustion. The USSFM V1.0 had good predictions on the H2% in all tests, and on other variables at a level of the lower oxygen feed. Provided with higher oxygen feed, the USSFM V1.0 simulated hotter temperatures, higher CO% and lower CO2%. Errors were explained by assumptions of equilibrium combustion, adiabatic reactors, reaction kinetics, etc. By investigating specific modeling data, gas-particle convective heat transfers were found to be critical in energy balance equations of both emulsion gas and particles, while bubble size controlled both the mass and energy balance equations of bubble gas. Parametric study

  2. Utilization of virtual reality for reading the superheated emulsion detector

    Energy Technology Data Exchange (ETDEWEB)

    Santos Sobrinho, Jose C.; Santo, Andre C.E.; Pereira, Claudio M.N.A.; Mol, Antonio C.A., E-mail: volksparati@hotmail.com, E-mail: cotelli.andre@gmail.com, E-mail: cmnap@ien.gov.br, E-mail: mol@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    This paper presents a method based on Virtual Reality for reading the Superheated Emulsion Detector (Bubble Detector). The proposed method is an alternative to: automatic counters offered by the manufacturers of detectors, since they have a relatively high cost (acquisition, maintenance and periodic calibration), and visual counting of detectors, since it only has an advantage when there are a small number of bubbles. The method starts with the collection of detector's digital images in order to obtain a sequence of images to create an animation that is displayed with the help of Virtual Reality. To this end, it is modeled, using OpenGL graphics library, a virtual environment for visualizing and manipulating virtual detector. It is made, then a calibration of this virtual environment thus ensuring the correspondence of the model with reality. The reading of the detector (bubbles count) is made visually by the user with the assistance of stereo vision and a 3D cursor to navigation, marking and counting the bubbles. The user views a further auxiliary display that shows the three-dimensional cursor position, the labeled amount of bubbles and the measured dose. After testing, the following results were achieved: better precision in counting the bubbles compared with the 10% reported by the manufacturer of the automatic reader; achieving a low cost tool that requires no calibration constant in the process of maintenance and/or lifetime; minimizing the problem of manual counting for large number of bubbles and ease of use, because can be operated by a common user. (author)

  3. Optical-cell evidence for superheated ice under gas-hydrate-forming conditions

    Science.gov (United States)

    Stern, L.A.; Hogenboom, D.L.; Durham, W.B.; Kirby, S.H.; Chou, I.-Ming

    1998-01-01

    We previously reported indirect but compelling evidence that fine-grained H2O ice under elevated CH4 gas pressure can persist to temperatures well above its ordinary melting point while slowly reacting to form methane clathrate hydrate. This phenomenon has now been visually verified by duplicating these experiments in an optical cell while observing the very slow hydrate-forming process as the reactants were warmed from 250 to 290 K at methane pressures of 23 to 30 MPa. Limited hydrate growth occurred rapidly after initial exposure of the methane gas to the ice grains at temperatures well within the ice subsolidus region. No evidence for continued growth of the hydrate phase was observed until samples were warmed above the equilibrium H2O melting curve. With continued heating, no bulk melting of the ice grains or free liquid water was detected anywhere within the optical cell until hydrate dissociation conditions were reached (292 K at 30 MPa), even though full conversion of the ice grains to hydrate requires 6-8 h at temperatures approaching 290 K. In a separate experimental sequence, unreacted portions of H2O ice grains that had persisted to temperatures above their ordinary melting point were successfully induced to melt, without dissociating the coexisting hydrate in the sample tube, by reducing the pressure overstep of the equilibrium phase boundary and thereby reducing the rate of hydrate growth at the ice-hydrate interface. Results from similar tests using CO2 as the hydrate-forming species demonstrated that this superheating effect is not unique to the CH4-H2O system.

  4. Studies on electrical double layer capacitor with a low-viscosity ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate as electrolyte

    Indian Academy of Sciences (India)

    G P Pandey; S A Hashmi

    2013-08-01

    The performance of an electrical double layer capacitor (EDLC) composed of high surface area activated carbon electrodes and a new ionic liquid, 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIm]TCB, as the electrolyte has been investigated by impedance spectroscopy, cyclic voltammetry and galvanostatic charge–discharge studies. The high ionic conductivity (∼1.3 × 10-2 S cm-1 at 20 °C) and low viscosity (∼22 cP) of the ionic liquid, [EMIm]TCB, make it attractive as electrolyte for its use in EDLCs. The optimum capacitance value of 195.5 F g-1 of activated carbon has been achieved with stable cyclic performance.

  5. π(+)-π(+) stacking of imidazolium cations enhances molecular layering of room temperature ionic liquids at their interfaces.

    Science.gov (United States)

    Tang, Fujie; Ohto, Tatsuhiko; Hasegawa, Taisuke; Bonn, Mischa; Nagata, Yuki

    2017-01-25

    The interfacial structure of room temperature ionic liquids (RTILs) controls many of the unique properties of RTILs, such as the high capacitance of RTILs and the efficiency of charge transport between RTILs and electrodes. RTILs have been experimentally shown to exhibit interfacial molecular layering structures over a 10 Å length scale. However, the driving force behind the formation of these layered structures has not been resolved. Here, we report ab initio molecular dynamics simulations of imidazolium RTIL/air and RTIL/graphene interfaces along with force field molecular dynamics simulations. We find that the π(+)-π(+) interaction of imidazolium cations enhances the layering structure of RTILs, despite the electrostatic repulsion. The length scales of the molecular layering at the RTIL/air and RTIL/graphene interfaces are very similar, manifesting the limited effect of the substrate on the interfacial organization of RTILs.

  6. Effect of π-π+ stacking on the layering of ionic liquids confined to an amorphous carbon surface.

    Science.gov (United States)

    Gong, Xiao; Kozbial, Andrew; Rose, Franck; Li, Lei

    2015-04-08

    In the current paper, AFM studies were conducted on nanometer-thick ionic liquids (ILs) confined to an amorphous carbon (AC) surface, which is critical to the design of the next-generation media lubricant for hard disk drives (HDDs). The results indicated that the existence of the delocalized ring in the cation is critical to layering of ILs. Extended layering was observed only when there is imidazolium ring in the cation. When the imidazolium ring is replaced by an aliphatic moiety, "drop-on-layer" (dewetting) structure was observed. On the basis of the experimental results, we proposed that π-π+ stacking between sp(2) carbon in the AC and the imidazolium cation in the ILs is the key to the extended layering of ILs at the ILs/AC interface.

  7. Characterization of R-134A superheated droplet detector for neutron detection

    CERN Document Server

    Mondal, Prasanna Kumar; Chatterjee, Barun Kumar

    2013-01-01

    R-134A (C2H2F4) is a low cost, easily available and chlorine free refrigerant, which in its superheated state can be used as an efficient neutron detector. Due to its high solubility in water the R-134A based superheated droplet detectors (SDD) are usually very unstable unless the detector is fabricated using a suitable additive, which stabilizes the detector. The SDD is known to have superheated droplets distributed in a short-lived and in a relatively longer-lived metastable state. We have studied the detector response to neutrons using a 241AmBe neutron source and obtained the temperature variation of the nucleation parameters and the interstate kinetics of these droplets using a two-state model.

  8. Tailoring the interfaces between nematic liquid crystal emulsions and aqueous phases via layer-by-layer assembly.

    Science.gov (United States)

    Tjipto, Elvira; Cadwell, Katie D; Quinn, John F; Johnston, Angus P R; Abbott, Nicholas L; Caruso, Frank

    2006-10-01

    We report the assembly of polyelectrolyte multilayer (PEM) films at the interfaces of thermotropic liquid crystal (LC) droplets dispersed in an aqueous phase. Exposure of PEM-coated droplets to surfactant slowed the bipolar-to-radial ordering transition of the LCs by 2 orders of magnitude relative to naked droplets. This shows that PEMs can be used to influence the interactions of analytes with the LC cores of the droplets, allowing tuning of the LC emulsion sensing properties.

  9. Liquid Water- and Heat-Resistant Hybrid Perovskite Photovoltaics via an Inverted ALD Oxide Electron Extraction Layer Design.

    Science.gov (United States)

    Kim, In Soo; Cao, Duyen H; Buchholz, D Bruce; Emery, Jonathan D; Farha, Omar K; Hupp, Joseph T; Kanatzidis, Mercouri G; Martinson, Alex B F

    2016-12-14

    Despite rapid advances in conversion efficiency (>22%), the environmental stability of perovskite solar cells remains a substantial barrier to commercialization. Here, we show a significant improvement in the stability of inverted perovskite solar cells against liquid water and high operating temperature (100 °C) by integrating an ultrathin amorphous oxide electron extraction layer via atomic layer deposition (ALD). These unencapsulated inverted devices exhibit a stable operation over at least 10 h when subjected to high thermal stress (100 °C) in ambient environments, as well as upon direct contact with a droplet of water without further encapsulation.

  10. Preparation of Cu-Sn Layers on Polymer Substrate by Reduction-Diffusion Method Using Ionic Liquid Baths

    OpenAIRE

    Murase, Kuniaki; Ito, Akira; Ichii, Takashi; Sugimura, Hiroyuki

    2011-01-01

    A novel metallization of non-conductive epoxy substrate with Cu-Sn “speculum alloy, ” or “white bronze, ” was performed through successive electrochemical processes: (i) conventional electroless deposition of pure Cu layer and (ii) subsequent electrochemical alloying of the resulting pure Cu layer with Sn using an ionic liquid bath at 150°C, a medium-low temperature. Availability of the Sn quasi-reference electrode for the alloying was verified, and the resulting compact and adhesive Cu-Sn la...

  11. Free Surface Command Layer for Photoswitchable Out-of-Plane Alignment Control in Liquid Crystalline Polymer Films.

    Science.gov (United States)

    Nakai, Takashi; Tanaka, Daisuke; Hara, Mitsuo; Nagano, Shusaku; Seki, Takahiro

    2016-01-26

    To date, reversible alignment controls of liquid crystalline materials have widely been achieved by photoreactive layers on solid substrates. In contrast, this work demonstrates the reversible out-of-plane photocontrols of liquid crystalline polymer films by using a photoresponsive skin layer existing at the free surface. A polymethacrylate containing a cyanobiphenyl side-chain mesogen adopts the planar orientation. Upon blending a small amount of azobenzene-containing side-chain polymer followed by successive annealing, segregation of the azobenzene polymer at the free surface occurs and induces a planar to homeotropic orientation transition of cyanobiphenyl mesogens underneath. By irradiation with UV light, the mesogen orientation turns into the planar orientation. The orientation reverts to the homeotropic state upon visible light irradiation or thermally, and such cyclic processes can be repeated many times. On the basis of this principle, erasable optical patterning is performed by irradiating UV light through a photomask.

  12. Measuring ice- and liquid-water properties in mixed-phase cloud layers at the Leipzig Cloudnet station

    Science.gov (United States)

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

    2016-08-01

    An analysis of the Cloudnet data set collected at Leipzig, Germany, with special focus on mixed-phase layered clouds is presented. We derive liquid- and ice-water content together with vertical motions of ice particles falling through cloud base. The ice mass flux is calculated by combining measurements of ice-water content and particle Doppler velocity. The efficiency of heterogeneous ice formation and its impact on cloud lifetime is estimated for different cloud-top temperatures by relating the ice mass flux and the liquid-water content at cloud top. Cloud radar measurements of polarization and Doppler velocity indicate that ice crystals formed in mixed-phase cloud layers with a geometrical thickness of less than 350 m are mostly pristine when they fall out of the cloud.

  13. Gas phase acetic acid and its qualitative effects on snow crystal morphology and the quasi-liquid layer

    Directory of Open Access Journals (Sweden)

    T. N. Knepp

    2009-10-01

    Full Text Available A chamber was constructed within which snow crystals were grown on a string at various temperatures, relative humidities, and acetic acid gas phase mole fractions. The temperature, relative humidity, and acid mole fraction were measured for the first time at the point of crystal growth. Snow crystal morphological transition temperature shifts were recorded as a function of acid mole fraction, and interpreted according to the calculated acid concentration in the crystal's quasi-liquid layer, which is believed to have increased in thickness as a function of acid mole fraction, thereby affecting the crystal's morphology consistent with the hypothesis of Kuroda and Lacmann. Deficiencies in the understanding of the quasi-liquid layer and its role in determining snow crystal morphology are briefly discussed.

  14. Layer-by-layer encapsulated nano-emulsion of ionic liquid loaded with functional material for extraction of Cd(2+) ions from aqueous solutions.

    Science.gov (United States)

    Elizarova, Iuliia S; Luckham, Paul F

    2017-04-01

    Ionic liquids can serve as an environmentally-friendly replacement for solvents in emulsions, therefore they are considered suitable to be used as an emulsified medium for various active materials one of which are extractors of metal ions. Increasing the extraction efficiency is considered to be one of the key objectives when working with such extraction systems. One way to improve the extraction efficiency is to increase the contact area between the extractant and the working ionic solution. This can be accomplished by creating a nano-emulsion of ionic liquid containing such an extractant. Since emulsification of ionic liquid is not always possible in the sample itself, there is a necessity of creating a stable emulsion that can be added externally and on demand to samples from which metal ions need to be extracted. We propose a method of fabrication of a highly-stable extractant-loaded ionic liquid-in-water nano-emulsion via a low-energy phase reversal emulsification followed by continuous layer-by-layer polyelectrolyte deposition process to encapsulate the nano-emulsion and enhance the emulsion stability. Such a multilayered stabilized nano-emulsion was tested for extraction of Cd(2+) and Ca(2+) ions in order to determine its extraction efficiency and selectivity. It was found to be effective in the extraction of Cd(2+) ions with near 100% cadmium removal, as well as being selective since no Ca(2+) ions were extracted. The encapsulated emulsion was removed from samples post-extraction using two methods - filtration and magnetic separation, both of which were shown to be viable under different circumstances - larger and mechanically stronger capsules could be removed by filtration, however magnetic separation worked better for both smaller and bigger capsules. The long-term stability of nano-emulsion was also tested being a very important characteristic for its proposed use: it was found to be highly stable after four months of storage time.

  15. Simultaneous determination of cyclodol and diprazin by thin layer chromatography and high performance liquid chromatography.

    Science.gov (United States)

    Makharadze, R; Adeishvili, L; Chelidze, T; Imnadze, N; Nizharadze, N

    2009-11-01

    Ciklodol (trihexyphenidil)--the central and peripheral m-cholinoblocker is currently used with other antipsychotic drugs such as phenotiazines and tricycle antidepressants. For the purpose of simultaneous determination of ciklodol and diprazine, were selected two methods of analysis: Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC). During development of TLC method was studied the 10 visualizing system and 24 mobile systems. For individual or simultaneous determination of ciklodol and diprazine were recommended the following solvents' systems: 1. Toluene-acetone-ethanole-25%NH(4)OH (45:45: 7.5:2.5), 2. Hexane-ethyl acetate (15:5), 3. Chloroform-heptene-25%NH(4)OH (16:3:3), 4. Ethylacetate-hexane (10:10), 5. Acetonitrile-metanol (10:10) and 6.Heptene-chloroform-ethanol-25% NH(4)OH (5:10:3:1). As visualizing systems were chosen: Iodine vapors, blacklight (UV254) and reagent of FNP. Reagent of FNP gives colored spot just with diprazine and it is also could be used for separation of both objects in simultaneous analysis. Developed HPLC method of simultaneous determination of ciklodol and diprazine: like mobile phase is recommended: Acetonitril- 0.05M KH(2)PO4 (55:45) (v/v) +H(3)PO(4) (pH3.5), column EC250 x 4.6mm, with solid phase Nucleosil, flow rate 1ml/min, sample volume 40 microl. In given conditions, the retention time of ciklodol is 6.005min and diprazine 7.227min. Developed method of simultaneous determination and separation of ciklodol and diprazine in respective mixtures could be successfully applied as in the pharmaceutical, as well in the chemical-toxicological laboratories.

  16. Casting structure of pure aluminum by electric pulse modification at different superheated temperatures

    Institute of Scientific and Technical Information of China (English)

    Jingang Qi; Jianzhong Wang; Xingjiang Liu; Bing Wang; Daqiang Cang

    2005-01-01

    Electric pulse modification (EPM) is a novel technique that reduces grain size by altering the structure of a melt. It was investigated that the response of the casting structure of high pure aluminum to EPM in different superheated melts. The results indicate that the grain refining effect of a given pulse electric field holds an optimal temperature range, moreover, a lower or higher superheated temperature will both disadvantage the improvements of casting structure. It essentially lies in the cooperative action between the distorted absorption of clusters and the activated capability of atoms in the aluminum melt.

  17. Static and dynamic superheated water extraction of essential oil components from Thymus vulgaris L.

    Science.gov (United States)

    Dawidowicz, Andrzej L; Rado, Ewelina; Wianowska, Dorota

    2009-09-01

    Superheated water extraction (SWE) performed in both static and dynamic condition (S-SWE and D-SWE, respectively) was applied for the extraction of essential oil from Thymus vulgaris L. The influence of extraction pressure, temperature, time, and flow rate on the total yield of essential oil and the influence of extraction temperature on the extraction of some chosen components are discussed in the paper. The SWE extracts are related to PLE extracts with n-hexane and essential oil obtained by steam distillation. The superheated water extraction in dynamic condition seems to be a feasible option for the extraction of essential oil components from T. vulgaris L.

  18. PID Controller Parameters Tuning Based-on Satisfaction for Superheated Steam Temperature of Power Station Boiler

    Directory of Open Access Journals (Sweden)

    Benxian Xiao

    2014-06-01

    Full Text Available Proposed the PID controller parameters tuning method based-on New Luus-Jaakola (NLJ algorithm and satisfaction idea. According to the different requirements of each performance index, designed the satisfaction function with fuzzy constraint attributes, and then determined the comprehensive satisfaction function for PID tuning by NLJ algorithm. Provided the steps of PID controller parameters tuning based on the NLJ algorithm and satisfaction, and applied this tuning method to the cascade control system of superheated steam temperature for Power Station Boiler. Finally the simulation and experiment results have shown the proposed method has good dynamic and static control performances for this complicated superheated steam temperature control system.

  19. Surface tension determination using data of the evolution of thermocapillary deformations in a locally heated liquid layer

    Directory of Open Access Journals (Sweden)

    Barakhovskaia Ella

    2017-01-01

    Full Text Available Identifying liquids in chemical technologies and in the oil industry is an actual problem. Such identifications can be made using individual characteristics of thermocapillary flows and deformations in the horizontal layers of the investigated liquids. Numerical algorithms and calculating code have been developed for solving inverse problems for identifying properties of liquid. As additional information for inverse problem a function of thermocapillary response is used. The algorithm for solving inverse problem is based on solving problem of minimizing the residual function. The minimum is obtained numerically by the Newton’s method. Numerical calculations have been made for silicone oil. Thermocapillary responses have been calculated for different values of the coefficients. The developed algorithms have been tested on synthetic data, which have been obtained from the solution of direct problems. The developed algorithms have shown a good convergence and efficiency.

  20. Preparation of CuGaSe{sub 2} absorber layers for thin film solar cells by annealing of efficiently electrodeposited Cu-Ga precursor layers from ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Steichen, M., E-mail: marc.steichen@uni.lu; Larsen, J.; Guetay, L.; Siebentritt, S.; Dale, P.J.

    2011-08-31

    CuGaSe{sub 2} absorber layers were prepared on molybdenum substrates by electrochemical codeposition of copper and gallium and subsequential annealing in selenium vapour. The electrodeposition was made from a deep eutectic based ionic liquid consisting of choline chloride/urea (Reline) with a plating efficiency of over 85%. The precursor film composition is controlled by the ratio of the copper to gallium fluxes under hydrodynamic conditions and by the applied deposition potential. X-ray diffraction reveals CuGa{sub 2} alloying during the electrodeposition and CuGaSe{sub 2} formation after annealing. Photoluminescence (PL) and photocurrent spectroscopy revealed the good opto-electronic properties of the CuGaSe{sub 2} absorber films. The absorber layers have been converted to full devices with the best device achieving 4.0 % solar conversion efficiency.

  1. Layer by layer assembly of catalase and amine-terminated ionic liquid onto titanium nitride nanoparticles modified glassy carbon electrode: Study of direct voltammetry and bioelectrocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Saadati, Shagayegh [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Salimi, Abdollah, E-mail: absalimi@uok.ac.ir [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Research Center for Nanotechnology, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Hallaj, Rahman; Rostami, Amin [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of)

    2012-11-13

    Highlights: Black-Right-Pointing-Pointer Catalase and amine-terminated ionic liquid were immobilized to GC/TiNnp with LBL assembly method. Black-Right-Pointing-Pointer First a thin layer of NH{sub 2}-IL is covalently attached to GC/TiNnp electrode using electro-oxidation. Black-Right-Pointing-Pointer With alternative assemble of IL and catalase with positive and negative charged, multilayer was formed. Black-Right-Pointing-Pointer Immobilized catalase shows excellent electrocatalytic activity toward H{sub 2}O{sub 2} reduction. Black-Right-Pointing-Pointer Biosensor response is directly correlated to the number of bilayers. - Abstract: A novel, simple and facile layer by layer (LBL) approach is used for modification of glassy carbon (GC) electrode with multilayer of catalase and nanocomposite containing 1-(3-Aminopropyl)-3-methylimidazolium bromide (amine terminated ionic liquid (NH{sub 2}-IL)) and titanium nitride nanoparticles (TiNnp). First a thin layer of NH{sub 2}-IL is covalently attached to GC/TiNnp electrode using electro-oxidation method. Then, with alternative self assemble positively charged NH{sub 2}-IL and negatively charged catalase a sensitive H{sub 2}O{sub 2} biosensor is constructed, whose response is directly correlated to the number of bilayers. The surface coverage of active catalase per bilayer, heterogeneous electron transfer rate constant (k{sub s}) and Michaelis-Menten constant (K{sub M}) of immobilized catalase were 3.32 Multiplication-Sign 10{sup -12} mol cm{sup -2}, 5.28 s{sup -1} and 1.1 mM, respectively. The biosensor shows good stability, high reproducibility, long life-time, and fast amperometric response with the high sensitivity of 380 {mu}A mM{sup -1} cm{sup -2} and low detection limit of 100 nM at concentration range up to 2.1 mM.

  2. Ultra Low Level Environmental Neutron Measurements Using Superheated Droplet Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, A.C. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Estrada Nacional 10 - km 139.7, 2695-066 Bobadela LRS (Portugal); Centro de Fisica Nuclear, Universidade de Lisboa. Av. Prof. Gama Pinto, 2, 1649- 003 Lisboa (Portugal); Felizardo, M.; Girard, T.A.; Kling, A.; Ramos, A.R. [Centro de Fisica Nuclear, Universidade de Lisboa. Av. Prof. Gama Pinto, 2, 1649- 003 Lisboa (Portugal); Marques, J.G.; Prudencio, M.I.; Marques, R.; Carvalho, F.P. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Estrada Nacional 10 - km 139.7, 2695-066 Bobadela LRS (Portugal)

    2015-07-01

    Through the application of superheated droplet detectors (SDDs), the SIMPLE project for the direct search for dark matter (DM) reached the most restrictive limits on the spin-dependent sector to date. The experiment is based on the detection of recoils following WIMP-nuclei interaction, mimicking those from neutron scattering. The thermodynamic operation conditions yield the SDDs intrinsically insensitive to radiations with linear energy transfer below ∼150 keVμm{sup -1} such as photons, electrons, muons and neutrons with energies below ∼40 keV. Underground facilities are increasingly employed for measurements in a low-level radiation background (DM search, gamma-spectroscopy, intrinsic soft-error rate measurements, etc.), where the rock overburden shields against cosmic radiation. In this environment the SDDs are sensitive only to α-particles and neutrons naturally emitted from the surrounding materials. Recently developed signal analysis techniques allow discrimination between neutron and α-induced signals. SDDs are therefore a promising instrument for low-level neutron and α measurements, namely environmental neutron measurements and α-contamination assays. In this work neutron measurements performed in the challenging conditions of the latest SIMPLE experiment (1500 mwe depth with 50-75 cm water shield) are reported. The results are compared with those obtained by detailed Monte Carlo simulations of the neutron background induced by {sup 238}U and {sup 232}Th traces in the facility, shielding and detector materials. Calculations of the neutron energy distribution yield the following neutron fluence rates (in 10{sup -8} cm{sup -2}s{sup -1}): thermal (<0.5 eV): 2.5; epithermal (0.5 eV-100 keV): 2.2; fast (>1 MeV): 3.9. Signal rates were derived using standard cross sections and codes routinely employed in reactor dosimetry. The measured and calculated neutron count rates per unit of active mass were 0.15 ct/kgd and 0.33 ct/kg-d respectively. As the major

  3. Photonic defect modes in a cholesteric liquid crystal with a resonant nanocomposite layer and a twist defect

    Science.gov (United States)

    Vetrov, Stepan Ya.; Pyatnov, Maxim V.; Timofeev, Ivan V.

    2014-09-01

    We have studied spectral properties of a cholesteric liquid crystal with a combined defect consisting of a nanocomposite layer and a twist. The nanocomposite layer is made of metallic nanoballs dispersed in a transparent matrix and featuring effective resonant permittivity. A solution has been found for the transmission spectrum of circularly polarized waves in the structure. We have analyzed spectral splitting of the defect mode in the band gap of the cholesteric when its frequency coincides with the nanocomposite resonant frequency. Defect modes have characteristics strongly dependent on the magnitude and the sign of the phase difference of the cholesteric helix on both sides of the defect layer. It has been found that the band gap width and the position and localization degree of defect modes can be effectively controlled by external fields applied to the cholesteric.

  4. Photonic defect modes in a cholesteric liquid crystal with a resonant nanocomposite layer and a twist defect.

    Science.gov (United States)

    Vetrov, Stepan Ya; Pyatnov, Maxim V; Timofeev, Ivan V

    2014-09-01

    We have studied spectral properties of a cholesteric liquid crystal with a combined defect consisting of a nanocomposite layer and a twist. The nanocomposite layer is made of metallic nanoballs dispersed in a transparent matrix and featuring effective resonant permittivity. A solution has been found for the transmission spectrum of circularly polarized waves in the structure. We have analyzed spectral splitting of the defect mode in the band gap of the cholesteric when its frequency coincides with the nanocomposite resonant frequency. Defect modes have characteristics strongly dependent on the magnitude and the sign of the phase difference of the cholesteric helix on both sides of the defect layer. It has been found that the band gap width and the position and localization degree of defect modes can be effectively controlled by external fields applied to the cholesteric.

  5. Characteristics of liquid water removal from the gas diffusion layer by reactant flow in a PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, K.; Park, J.; Li, X. [Waterloo Univ., ON (Canada). Dept. of Mechanical and Mechatronics Engineering

    2008-07-01

    Water in proton exchange membrane (PEM) fuel cells is accumulated in the gas diffusion layer (GDL) and removed by the static pressure gradient caused by the fast reactant flow in the flow channel. Reactants can leak into the neighbouring channels via the porous GDL and inhibit the removal of liquid water. This study examined the characteristics of liquid water removal from the GDL by measuring unsteady pressure drop in a PEM fuel cell in which the GDL was initially wetted with liquid water. GDL thickness was controlled by inserting metal shims between the fuel cell plates. The experiment showed that the amount of pressure drop is inversely proportional to GDL thickness. Thicker GDLs with higher porosity levels increased cross flow. Liquid water removal was also influenced by the change of inlet Reynolds number, which demonstrated that air flow rates must be high enough for efficient water removal. Various GDL porosities and permeabilities were calculated, and their influence on the characteristics of liquid water removal were evaluated. A transparent flow channel design was used to visualize water movement in the GDL. It was concluded that the effects of cross flow and GDL compression levels should be considered in the analysis and design of PEM fuel cells. 23 refs., 8 figs.

  6. Experimental Study on the Characteristics of Liquid Layer and Disturbance Waves in Horizontal Annular Flow

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow.To resolve this issue,using five parallel-wire conductance probes,time records of local liquid film thickness at five circumferential positions were collected.The characteristics of circumferential liquid film thickness profiles and its variation with gas and liquid velocities were obtained.The basic features of probability distribution function,probability density function,auto-correlation,cross-correlation and power spectrum density function of the disturbance waves in annular flow were studied respectively.The characterstics of circumferential profiles of disturbance waves and its variation with gas and liquid velocities were presented.

  7. A MATHEMATICAL MODEL OF THE ROASTING CHESTNUTS PROCESS BY SUPERHEATED STEAM

    Directory of Open Access Journals (Sweden)

    A. N. Ostrikov

    2013-01-01

    Full Text Available The mathematic modeling for chestnuts roasting process by superheated steam is conducted. Diffusion and thermal diffusion coefficients are used for process description. Initial conditions and boundary conditions of the third kind for thermal conductivity and mass transfer equations are set.

  8. Inhibition of lipid oxidation in pork bundles processing by superheated steam frying.

    Science.gov (United States)

    Huang, Tzou-Chi; Ho, Chi-Tang; Fu, Hui-Yin

    2004-05-19

    The effect of superheated steam treatment on the oxidative stability of lipids in packaged Zousoon (pork bundles) was investigated. The aroma quality of Zousoon samples was evaluated by sensory analysis and chromatographic analysis of volatiles. Results of this study indicated that oxidation of lipids occurred in pan-fried Zousoon after prolonged storage. Significant amounts of highly volatile compounds such as formaldehyde, acetaldehyde, acetone, and hexanal in Zousoon were identified by a modified method of cysteamine derivatization followed by gas chromatography-mass spectrometry (GC-MS) analysis. Superheated steam was found to be effective in suppressing lipid oxidation in canned Zousoon as compared with Zousoon fried by the conventional method in a frying pan. The superheated steam-fried samples had relatively low thiobarbituric acid reactive substance (TBARS) and peroxide (POV) values before and after storage, whereas samples prepared by pan frying had relatively high TBARS and POV values before and after storage. Superheated steam-fried Zousoon had superior lipid stability to that prepared by the conventional pan-frying method.

  9. Size asymmetric hard spheres as a convenient model for the capacitance of the electrical double layer of an ionic liquid.

    Science.gov (United States)

    Lamperski, Stanisław; Sosnowska, Joanna; Bhuiyan, Lutful Bari; Henderson, Douglas

    2014-01-07

    Even though ionic liquids are composed of nonspherical ions, it is shown here that the general features of the capacitance of an electrical double layer can be obtained using a charged hard sphere model. We have shown in our earlier studies that at high electrolyte concentrations or large magnitudes of the electrode charge density the fact that the ions have a finite size, and are not point ions, cause the capacitance near the potential of zero charge to increase and change from a minimum to a maximum as the ionic concentration is increased and to decrease as the magnitude of the electrode charge density increases. Here, we show that the asymmetry of the capacitance of an ionic liquid can be explained qualitatively by using spherical ions of different size without attempting to introduce the ionic shape in a detailed manner. This means that the general features of the capacitance of the double layer of an ionic liquid can be studied without using a complex model, although the study of the density or charge profiles of an ionic fluid would require one. However, this is often unnecessary in the analysis of many experiments.

  10. Improved Carrier Mobility in Few-Layer MoS2 Field-Effect Transistors with Ionic-Liquid Gating

    Science.gov (United States)

    Perera, Meeghage; Lin, Ming-Wei; Chuang, Hsun-Jen; Chamlagain, Bhim; Wang, Chongyu; Tan, Xuebin; Cheng, Mark; Tománek, David; Zhou, Zhixian

    2014-03-01

    We report the fabrication of ionic liquid (IL) gated field-effect transistors (FETs) consisting of bilayer and few-layer MoS2. Our transport measurements indicate that the electron mobility μ ~ 60 cm2V-1s-1 at 250 K in ionic liquid gated devices exceeds significantly that of comparable back-gated devices. IL-FETs display a mobility increase from ~100 cm2V-1s-1 at 180 K to ~220 cm2V-1s-1 at 77 K in good agreement with the true channel mobility determined from four-terminal measurements, ambipolar behavior with a high ON/OFF ratio >107 (104) for electrons (holes), and a near ideal sub-threshold swing of ~50 mV/dec at 250 K. We attribute the observed performance enhancement, specifically the increased carrier mobility that is limited by phonons, to the reduction of the Schottky barrier at the source and drain electrode by band bending caused by the ultrathin ionic-liquid dielectric layer. In addition, graphene contacted MoS2 FETs with IL-gating will also be discussed. This work was supported by NSF (No. ECCS-1128297).

  11. Smooth/rough layering in liquid-crystalline/gel state of dry phospholipid film, in relation to its ability to generate giant vesicles

    CERN Document Server

    Hishida, M; Yoshikawa, K; Hishida, Mafumi; Seto, Hideki; Yoshikawa, Kenichi

    2005-01-01

    Morphological changes in a dry phospholipid film on a solid substrate were studied below and above the main transition temperature, between the gel and liquid-crystalline phases by phase-contrast microscopy and AFM. A Phospholipid film in the liquid-crystalline phase exhibits flat, smooth layering, whereas that in the gel phase shows rough, random layering. These film morphologies are discussed in relation to the ability to form giant vesicles through the natural swelling method.

  12. Ionic Liquid-Derived Imidazolium Cation Linkers for the Layer-by-Layer Assembly of Polyoxometalate-MWCNT Composite Electrodes with High Power Capability.

    Science.gov (United States)

    Genovese, Matthew; Lian, Keryn

    2016-07-27

    Imidazolium cations derived from ionic liquids were demonstrated as effective linker molecules for the layer-by-layer (LbL) deposition of polyoxometalates (POMs) to increase the charge storage of multi-walled carbon nanotube (MWCNT) electrodes. MWCNTs modified with GeMo12O40(4-) (GeMo12) via an imidazolium cation linker demonstrated highly reversible redox reactions and a capacitance of 84 F cm(-3), close to 4 times larger than bare CNT. Compared to CNT-GeMo12 composites fabricated with a conventional polyelectrolyte linker poly(diallyldimethylammonium chloride), (PDDA), the imidazolium cations resulted in lower POM loading, but higher conductivity and in turn superior performance at fast charge-discharge conditions. A polymerized imidazolium linker (PIL) was also synthesized based on the ethyl-vinyl-imidazolium monomer. CNT-GeMo12 composites fabricated with this PIL achieved high POM loading comparable to PDDA, while still maintaining the good conductivity and high rate capabilities shown by the monomer imidazolium units. The high conductivity imparted by the PIL is especially valuable for the fabrication of multilayer POM composites. Dual-layer GeMo12 O40(4-)-SiMo12O40(4-) (GeMo12-SiMo12) electrodes built with this PIL demonstrated a combined contribution of the individual POMs resulting in a capacitance of 191 F cm(-3), over nine times larger than bare MWCNT. The PIL dual layer composites also maintained 72% of this capacitance at a fast rate of 2 V s(-1), compared to just over 50% retention for similar electrodes fabricated with PDDA.

  13. TiO{sub 2} anatase films obtained by direct liquid injection atomic layer deposition at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Avril, L., E-mail: ludovic.avril@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Reymond-Laruinaz, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Decams, J.M. [Annealsys, rue de la Vieille Poste, 34055 Montpellier Cedex 1 (France); Bruyère, S.; Potin, V.; Lucas, M.C. Marco de; Imhoff, L. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France)

    2014-01-01

    TiO{sub 2} thin films were grown by direct liquid injection atomic layer deposition (DLI-ALD) with infrared rapid thermal heating using titanium tetraisopropoxide and water as precursors. This titanium tetraisopropoxide/water process exhibited a growth rate of 0.018 nm/cycle in a self-limited ALD growth mode at 280 °C. Scanning electron microscopy and atomic force microscopy analyses have shown a smooth surface with a low roughness. XPS results demonstrated that the films were pure and close to the TiO{sub 2} stoichiometric composition in depth. Raman spectroscopy revealed that the films were crystallized to the anatase structure in the as-deposited state at low temperature without necessity of high temperature annealing. Results obtained demonstrate that the liquid injection ALD is an efficient method of elaborating titanium oxide films using titanium tetraisopropoxide as precursor.

  14. Synthesis and physical properties of new layered double hydroxides based on ionic liquids: Application to a polylactide matrix

    KAUST Repository

    Livi, Sébastien

    2012-12-01

    Ionic liquids based on tetraalkylphosphonium salts combined with different anions (decanoate and dodecylsulfonate) have been used as intercalating agents of layered double hydroxides (LDHs) by ion exchange. The synthesized phosphonium-treated LDHs display a dramatically improved thermal degradation and a significant increase in the interlayer distance as confirmed by thermogravimetric analysis (TGA) and X-ray Diffraction (XRD), respectively. To highlight the effect of thermostable ionic liquids, a very low amount of LDHs has been introduced within a polylactide (PLA) matrix and PLA/LDHs nanocomposites have been processed in melt by twin-screw extrusion. Then, transmission electron microscopy (TEM) analysis has been used to investigate the influence of ILs on the different morphologies of these nanocomposites. Even though the thermal stability of PLA matrix decreased, an excellent stiffness-toughness compromise has been obtained. © 2012 Elsevier Inc.

  15. Separation of Berberine Hydrochloride and Tetrahydropalmatine and Their Quantitative Analysis with Thin Layer Chromatography Involved with Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Jing Lu

    2015-01-01

    Full Text Available [BMIM]OH was used in mobile and stationary phase of thin layer chromatography (TLC to analyze berberine hydrochloride and tetrahydropalmatine for the first time. Supported imidazole ionic liquid with hydroxide ion on silica gel (SiO2·Im+·OH− was synthesized through simple procedure and characterized by Fourier transform infrared spectroscopy (FT-IR, elemental analysis, and scanning electron microscope (SEM. Moreover, on the plates prepared by SiO2·Im+·OH−, the contents of the above alkaloids in the Chinese patent medicine (CPM of “Stomacheasy” capsule were successfully determined by TLC scanner. The key conditions and chromatographic behaviors were also investigated in detail. According to similar ways, ionic liquids (ILs also can be used in other planar chromatographies in two modes. This study is expected to be helpful in expanding the application of IL and its bonded silica gel in TLC separation field.

  16. Direct electroplating of copper on tantalum from ionic liquids in high vacuum: origin of the tantalum oxide layer.

    Science.gov (United States)

    Schaltin, Stijn; D'Urzo, Lucia; Zhao, Qiang; Vantomme, André; Plank, Harald; Kothleitner, Gerald; Gspan, Christian; Binnemans, Koen; Fransaer, Jan

    2012-10-21

    In this paper, it is shown that high vacuum conditions are not sufficient to completely remove water and oxygen from the ionic liquid 1-ethyl-3-methylimidazolium chloride. Complete removal of water demands heating above 150 °C under reduced pressure, as proven by Nuclear Reaction Analysis (NRA). Dissolved oxygen gas can only be removed by the use of an oxygen scavenger such as hydroquinone, despite the fact that calculations show that oxygen should be removed completely by the applied vacuum conditions. After applying a strict drying procedure and scavenging of molecular oxygen, it was possible to deposit copper directly on tantalum without the presence of an intervening oxide layer.

  17. A low-power all-optical bistable device based on a liquid crystal layer embedded in thin gold films

    Science.gov (United States)

    Takase, Yuki; Tien Thanh, Pham; Fujimura, Ryushi; Kajikawa, Kotaro

    2014-04-01

    An all-optical bistable (AOB) resonator device composed of a 430-nm-thick liquid crystal (LC) layer embedded in two thin gold films (MLM) is reported in this paper. This device allows the use of the incident illumination at normal incidence, whereas the previous AOB devices based on twisted nematic (TN)-LC function only for illumination at oblique incidence. The fastest switching time was measured to be 1.8 ms, which is significantly faster than that of TN-LC. Because the MLM device operates free from electronic circuits, it is promising for two-dimensional optical data processing, random access optical memories, and spatial light modulators.

  18. Strengthened nonlinearity in liquid crystal panel with ZnSe aligning layers due to surface charge accumulation

    Science.gov (United States)

    Zhao, Hua; Xue, Tingyu; Fu, Jiayin; Zhang, Jingwen

    2015-09-01

    With ZnSe thin films as aligning layers in fabricating liquid crystal (LC) panel with pentylcyanobiphenyl doped with C60, the response time in writing holograms was shortened to milliseconds. When two laser beams were overlapped in an LC panel, 2D diffraction patterns were observed, along with exponential gain coefficient highly LC and ZnSe thickness dependent. In addition, energy transferring in subwavelength scale through surface grating was evident. By using a hybrid LC panel, it was found the energy transferring direction was voltage polarity and thickness dependent. Electrostatic modification based surface plasmon polariton excitation was proposed to explain all the findings

  19. Atomic motions in the layered copper pseudochalcogenide CuNCN indicative of a quantum spin-liquid scenario

    Science.gov (United States)

    Tchougréeff, Andrei L.; Stoffel, Ralf P.; Houben, Andreas; Jacobs, Philipp; Dronskowski, Richard; Pregelj, Matej; Zorko, Andrej; Arčon, Denis; Zaharko, Oksana

    2017-06-01

    We explore the thermodynamic properties of the layered copper(II) carbodiimide CuNCN by heat-capacity measurements and investigate the corresponding thermal atomic motions by means of neutron powder diffraction as well as inelastic neutron scattering. The experiments are complemented by a combination of density-functional calculations, phonon analysis and analytic theory. The existence of a soft flexural mode—bending of the layers, characteristic for the material structure—is established in the phonon spectrum of CuNCN by giving characteristic temperature-dependent contributions to the heat capacity and atomic displacement parameters. The agreement with the neutron data allows us to extract a residual—on top of the lattice—presumably spinon contribution to the heat capacity \\propto {{T}2} , speaking in favor of the spin-liquid picture of the electronic phases of CuNCN.

  20. Unravelling the electrochemical double layer by direct probing of the solid/liquid interface

    Science.gov (United States)

    Favaro, Marco; Jeong, Beomgyun; Ross, Philip N.; Yano, Junko; Hussain, Zahid; Liu, Zhi; Crumlin, Ethan J.

    2016-08-01

    The electrochemical double layer plays a critical role in electrochemical processes. Whilst there have been many theoretical models predicting structural and electrical organization of the electrochemical double layer, the experimental verification of these models has been challenging due to the limitations of available experimental techniques. The induced potential drop in the electrolyte has never been directly observed and verified experimentally, to the best of our knowledge. In this study, we report the direct probing of the potential drop as well as the potential of zero charge by means of ambient pressure X-ray photoelectron spectroscopy performed under polarization conditions. By analyzing the spectra of the solvent (water) and a spectator neutral molecule with numerical simulations of the electric field, we discern the shape of the electrochemical double layer profile. In addition, we determine how the electrochemical double layer changes as a function of both the electrolyte concentration and applied potential.

  1. Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer

    DEFF Research Database (Denmark)

    Pouzet, Eric; De Cupere, Vinciane; Heintz, Christophe

    2009-01-01

    A convenient method to induce face-on orientation of an alkoxy phtalocyanine discotic mesogen is described. The alignment is imposed by the confinement of the discotic thin films with a top sacrificial polymer layer that is easily removed by washing with a selective solvent, after thermal annealing...... to the substrate in an essentially homeotropic arrangement over large lateral length scales and the persistence of this desirable alignment after removal of the layer....

  2. The Reaction of Carbonates in Contact with Superheated Silicate Melts: New Insights from MEMIN Laser Melting Experiments

    Science.gov (United States)

    Hamann, C.; Hecht, L.; Schäffer, S.; Deutsch, A.; Lexow, B.

    2016-08-01

    The reaction of carbonates in contact with silicate impact melts is discussed quite controversially in the impact community. Here, we discuss four MEMIN laser melting experiments involving carbonates in contact with superheated silicate melts.

  3. Liquid-Phase Deposition of CIS Thin Layers: Final Report, February 2003--July 2005

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, F.; Pirouz, P.

    2006-02-01

    The goal of this project was to fabricate single-phase CIS (a-Cu-In-Se, stoichiometric composition: CuInSe2) thin films for photovoltaic applications from a liquid phase - a Cu-In-Se melt of appropriate composition. This approach of liquid-phase deposition (LPD) is based on the new phase diagram we have established for Cu-In-Se, the first complete equilibrium phase diagram of this system. The liquidus projection exhibits four composition fields in which the primary solid phase, i.e., the first solid material that forms on cooling down from an entirely liquid state, is a-CuInSe2. Remarkably, none of the four composition fields is anywhere near the stoichiometric composition (CuInSe2) of a-CuInSe2. The results demonstrate that the proposed technique is indeed capable of producing films with a particularly large grain size and a correspondingly low density of grain boundaries. To obtain films sufficiently thin for solar cell applications and with a sufficiently smooth surface, it is advantageous to employ a sliding boat mechanism. Future work on liquid-phase deposition of CIS should focus on the interaction between the melt and the substrate surface, the resulting CIS interfaces, the surface morphology of the LPD-grown films, and, of course, the electronic properties of the material.

  4. Hairy foam : thin layers of carbon nanofibers as catalyst support for liquid phase reactions

    NARCIS (Netherlands)

    Chinthaginjala, Jitendra Kumar

    2010-01-01

    Catalytic multiphase reactors are at the heart of many chemical industries. They allow efficient contact between gas and/or liquid reactant phases with solid catalysts increasing reaction rates. In practice, the higher reaction rates can be taken advantage of only under the condition that the transf

  5. The development of self-assembled liquid crystal display alignment layers

    NARCIS (Netherlands)

    Hoogboom, J.; Elemans, J.A.A.W.; Rowan, A.E.; Rasing, T.H.M.; Nolte, R.J.M.

    2007-01-01

    From simple pocket calculators to mobile telephones and liquid crystal display (LCD)-TV, over the past few decades, devices based on LCD technology have proliferated and can now be found in all conceivable aspects of everyday life. Although used in cutting-edge technology, it is surprising that a vi

  6. Comparative analysis of the microbial diversity in liquid and foaming layer in biogas reactors

    DEFF Research Database (Denmark)

    Campanaro, Stefano; Treu, Laura; Kougias, Panagiotis

    2014-01-01

    to the microbial composition of the digesters (Moeller et al., 2012). In the cited literature, it has been reported that specific microorganisms, which are mainly filamentous (e.g. Gordonia species, Microthrix parvicella), are attached to biogas bubbles and transferred to the air/liquid interface of sludge...

  7. Antiferroelectric surface layers in a liquid crystal as observed by synchrotron x-ray scattering

    DEFF Research Database (Denmark)

    Gramsbergen, E. F.; de Jeu, W. H.; Als-Nielsen, Jens Aage

    1986-01-01

    The X-ray reflectivity form the surface of a liquid crystal with terminally polar (cyano substituted) molecules has been studied using a high-resolution triple-axis X-ray spectrometer in combination with a synchrotron source. It is demonstrated that at the surface of the smectic Al phase a few...

  8. Hairy foam : thin layers of carbon nanofibers as catalyst support for liquid phase reactions

    NARCIS (Netherlands)

    Chinthaginjala, J.K.

    2010-01-01

    Catalytic multiphase reactors are at the heart of many chemical industries. They allow efficient contact between gas and/or liquid reactant phases with solid catalysts increasing reaction rates. In practice, the higher reaction rates can be taken advantage of only under the condition that the

  9. Spectroscopic metrics allow in situ measurement of mean size and thickness of liquid-exfoliated few-layer graphene nanosheets.

    Science.gov (United States)

    Backes, Claudia; Paton, Keith R; Hanlon, Damien; Yuan, Shengjun; Katsnelson, Mikhail I; Houston, James; Smith, Ronan J; McCloskey, David; Donegan, John F; Coleman, Jonathan N

    2016-02-21

    Liquid phase exfoliation is a powerful and scalable technique to produce defect-free mono- and few-layer graphene. However, samples are typically polydisperse and control over size and thickness is challenging. Notably, high throughput techniques to measure size and thickness are lacking. In this work, we have measured the extinction, absorption, scattering and Raman spectra for liquid phase exfoliated graphene nanosheets of various lateral sizes (90 ≤ 〈L〉 ≤ 810 nm) and thicknesses (2.7 ≤ 〈N〉 ≤ 10.4). We found all spectra to show well-defined dependences on nanosheet dimensions. Measurements of extinction and absorption spectra of nanosheet dispersions showed both peak position and spectral shape to vary with nanosheet thickness in a manner consistent with theoretical calculations. This allows the development of empirical metrics to extract the mean thickness of liquid dispersed nanosheets from an extinction (or absorption) spectrum. While the scattering spectra depended on nanosheet length, poor signal to noise ratios made the resultant length metric unreliable. By analyzing Raman spectra measured on graphene nanosheet networks, we found both the D/G intensity ratio and the width of the G-band to scale with mean nanosheet length allowing us to establish quantitative relationships. In addition, we elucidate the variation of 2D/G band intensities and 2D-band shape with the mean nanosheet thickness, allowing us to establish quantitative metrics for mean nanosheet thickness from Raman spectra.

  10. Evidence of extended solidlike layering in [Bmim][NTf2] ionic liquid thin films at room-temperature.

    Science.gov (United States)

    Bovio, Simone; Podestà, Alessandro; Lenardi, Cristina; Milani, Paolo

    2009-05-14

    We report the direct observation of solidlike ordering at room temperature of thin films of [Bmim][NTf2] ionic liquid on mica, amorphous silica, and oxidized Si(110). A statistical quantitative analysis of atomic force microscopy topographies shows that on these surfaces [Bmim][NTf2] forms layered structures, characterized by a perpendicular structural periodicity of approximately 0.6 nm. Remarkably, even the highest structures, up to 50 nm high, behave solidlike against the AFM probe. Conversely, on highly oriented pyrolitic graphite the ionic liquid forms nanometer-sized, liquidlike domains. The results of this study are directly relevant for those applications where ILs are employed in form of thin films supported on solid surfaces, such as in microelectromechanical or microelectronic devices. More generally, they suggest that at the liquid/solid interface the structural properties of ILs can be far more complex than those depicted so far, and prompt new fundamental investigations of the forces that drive supported ILs through a liquidlike-to-solidlike transition.

  11. Superheating and melting behaviors of Ag clusters with Ni coating studied by molecular dynamics and experiments

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using molecular dynamics with embedded-atom-type interatomicpotentials, we simulated the melting behavior of a spherical Ag3055 cluster coated with Ni. The semi-coherent Ag/Ni interface formed at low temperatures acts as an effective barrier against the surface melting and leads to a substantial superheating of the Ag cluster. The melting point was found to be about 100 K above the equilibrium melting point of the bulk Ag crystal (1230 K±15 K) and about 290 K above that (1040 K) of the free Ag3055 cluster. A superheating of 70 K was observed in the high-temperature differential scanning calorimetry measurement for Ag particles with a mean size of 30 nm embedded in Ni matrix prepared by means of melt-spinning. Melting is initiated locally at the defective interfacial area and then propagates inwards, suggesting a heterogeneously nucleated melting event at the Ag/Ni interface.

  12. Specific heat of superheated Al-10Sr alloy melts[Foundation item

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The specific heat of superheated Al-10Sr melts was determined at different heating rates between 1  K/min and 20  K/min using a differential scanning calorimeter(DSC). As a whole, the specific heat increases with increasing temperature. A hump is observed on the specific heat curve at the temperature corresponding to the phase boundary temperature dependent on heating rate. Moreover, the hump shifts to higher temperature in the measured temperature range from about 840  ℃ to 890  ℃ with increasing heating rate. At certain temperature in the higher superheated zone, the specific heat of the melt as a function of temperature shows a sharp rise . The result indicates that disorder zone fraction begins to increase while atom clusters fraction decreases at the breaking temperature.

  13. Thermocapillarity driven Instabilities in thin liquid layers subject to long-wave analysis

    Science.gov (United States)

    Narendranath, Aneet; Hermanson, James; Struthers, Allan; Kolkka, Robert; Allen, Jeffrey

    2012-11-01

    An evolution equation describing the dynamics of an evaporating liquid film has previously been developed from the governing equations of fluid dynamics after the application of the lubrication approximation and the choice of a viscous time scale. The authors have solved the evaporating liquid film evolution equation with a validated numeric program. The role of domain size and thermocapillarity on the formation of secondary finger like structures is studied. The effect that gravity has on the formation of these finger patterns is evaluated. It is observed that the formation of secondary structures is strongly tied to a balance between destabilizing thermocapillarity and stabilizing surface tension. The secondary structures are amplified in a zero gravity environment.

  14. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers.

    Science.gov (United States)

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-07-16

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials -trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems.

  15. Marangoni Bursting: Evaporation-Induced Emulsification of Binary Mixtures on a Liquid Layer

    Science.gov (United States)

    Keiser, L.; Bense, H.; Colinet, P.; Bico, J.; Reyssat, E.

    2017-02-01

    Adjusting the wetting properties of water through the addition of a miscible liquid is commonly used in a wide variety of industrial processes involving interfaces. We investigate experimentally the evolution of a drop of water and volatile alcohol deposited on a bath of oil: The drop spreads and spontaneously fragments into a myriad of minute droplets whose size strongly depends on the initial concentration of alcohol. Marangoni flows induced by the evaporation of alcohol play a key role in the overall phenomenon. The intricate coupling of hydrodynamics, wetting, and evaporation is well captured by analytical scaling laws. Our scenario is confirmed by experiments involving other combinations of liquids that also lead to this fascinating phenomenon.

  16. Generalized computer algorithms for enthalpy, entropy and specific heat of superheated vapors

    Science.gov (United States)

    Cowden, Michael W.; Scaringe, Robert P.; Gebre-Amlak, Yonas D.

    This paper presents an innovative technique for the development of enthalpy, entropy, and specific heat correlations in the superheated vapor region. The method results in a prediction error of less than 5 percent and requires the storage of 39 constants for each fluid. These correlations are obtained by using the Beattie-Bridgeman equation of state and a least-squares regression for the coefficients involved.

  17. A new method for neutron depth dosimetry with the superheated drop detector

    Energy Technology Data Exchange (ETDEWEB)

    D' Errico, F.; Apfel, R.E. (Yale Univ., New Haven, CT (USA))

    1990-01-01

    Chemical composition and energy response of the Superheated Drop Detector (SDD) suggested to us a new technique for the direct measurement of dose equivalent depth distributions in tissue-equivalent phantoms, independently of impinging neutron spectra and energy degradation with depth. The SDD performance has been tested against the depth-dose curves published in NCRP Report 38. The experimental results, in agreement with the expected values, confirm the applicability of this method. (author).

  18. Axial symmetric rotation of a partially immersed body in a liquid with a surfactant layer

    Indian Academy of Sciences (India)

    Sunil Datta; Nidhi Pandya

    2001-08-01

    This paper gives a simple integral formula to evaluate the torque on a slowly rotating symmetric body partially immersed in a viscous liquid covered by an adsorbed surface film. Besides the results known earlier, new results have also been derived for small values of the surface shear viscosity parameter . It is seen that the effect of in all cases is to increase the torque.

  19. Formation of nematic liquid crystals of sterically stabilized layered double hydroxide platelets

    NARCIS (Netherlands)

    Mourad, M.C.D.; Devid, E.J.; van Schooneveld, M.M.; Vonk, Ch.; Lekkerkerker, H.N.W.

    2008-01-01

    Colloidal platelets of hydrotalcite, a layered double hydroxide, have been prepared by coprecipitation at pH 11−12 of magnesium nitrate and aluminum nitrate at two different magnesium to aluminum ratios. Changing the temperature and ionic strength during hydrothermal treatment, the platelets were ta

  20. Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer

    DEFF Research Database (Denmark)

    Pouzet, Eric; De Cupere, Vinciane; Heintz, Christophe;

    2009-01-01

    . Thin films have been characterized by optical and atomic force microscopy, UV-Vis absorption spectroscopy, and grazing incidence wide angle X-ray scattering. The data converge in showing the central role of the sacrificial layer in promoting alignment with the planar molecules orienting parallel...

  1. Competition between capillarity, layering and biaxiality in a confined liquid crystal.

    Science.gov (United States)

    Varga, S; Martinez-Ratón, Y; Velasco, E

    2010-05-01

    The effect of confinement on the phase behaviour and structure of fluids made of biaxial hard particles (cuboids) is examined theoretically by means of Onsager second-order virial theory in the limit where the long particle axes are frozen in a mutually parallel configuration. Confinement is induced by two parallel planar hard walls (slit-pore geometry), with particle long axes perpendicular to the walls (perfect homeotropic anchoring). In bulk, a continuous nematic-to-smectic transition takes place, while shape anisotropy in the (rectangular) particle cross-section induces biaxial ordering. As a consequence, four bulk phases, uniaxial and biaxial nematic and smectic phases, can be stabilised as the cross-sectional aspect ratio is varied. On confining the fluid, the nematic-to-smectic transition is suppressed, and either uniaxial or biaxial phases, separated by a continuous transition, can be present. Smectic ordering develops continuously from the walls for increasing particle concentration (in agreement with the supression of nematic-smectic second-order transition at confinement), but first-order layering transitions, involving structures with n and n + 1 layers, arise in the confined fluid at high concentration. Competition between layering and uniaxial-biaxial ordering leads to three different types of layering transitions, at which the two coexisting structures can be both uniaxial, one uniaxial and another biaxial, or both biaxial. Also, the interplay between molecular biaxiality and wall interactions is very subtle: while the hard wall disfavours the formation of the biaxial phase, biaxiality is against the layering transitions, as we have shown by comparing the confined phase behaviour of cylinders and cuboids. The predictive power of Onsager theory is checked and confirmed by performing some calculations based on fundamental-measure theory.

  2. Light scattering study of the "pseudo-layer" compression elastic constant in a twist-bend nematic liquid crystal

    CERN Document Server

    Parsouzi, Z; Welch, C; Ahmed, Z; Mehl, G H; Baldwin, A R; Gleeson, J T; Lavrentovich, O D; Allender, D W; Selinger, J V; Jakli, A; Sprunt, S

    2016-01-01

    The nematic twist-bend (TB) phase, exhibited by certain achiral thermotropic liquid crystalline (LC) dimers, features a nanometer-scale, heliconical rotation of the average molecular long axis (director) with equally probable left- and right-handed domains. On meso to macroscopic scales, the TB phase may be considered as a stack of equivalent slabs or "pseudo-layers", each one helical pitch in thickness. The long wavelength fluctuation modes should then be analogous to those of a smectic-A phase, and in particular the hydrodynamic mode combining "layer" compression and bending ought to be characterized by an effective layer compression elastic constant $B_{eff}$ and average director splay constant $K_1^{eff}$. The magnitude of $K_1^{eff}$ is expected to be similar to the splay constant of an ordinary nematic LC, but due to the absence of a true mass density wave, $B_{eff}$ could differ substantially from the typical value of $\\sim 10^6$ Pa in a conventional smectic-A. Here we report the results of a dynamic l...

  3. Completion of Hot Test on Engineering Application Research of Heat-pump Evaporation Technology Dealing With Low Level Radioactive Liquid Waste

    Institute of Scientific and Technical Information of China (English)

    YAN; Xiao; YANG; Xue-feng; CHE; Jian-ye; ZHAO; Da-peng; SHEN; Zheng; YANG; Xiu-hua; QI; Zhi-qiang; ZHANG; Qiang

    2013-01-01

    The heat-pump evaporation technology is an efficient energy conservation waste liquid treatment technology by way of recycling and reusing of waste heat.The key technology is to retrieve the second steam coming from the evaporator,and to superheated steam by mean of increasing pressure at rising temperature in the steam compressor.And then the superheated steam needs to be returned to the

  4. Quenching of a highly superheated porous medium by injection of water

    Science.gov (United States)

    Fichot, F.; Bachrata, A.; Repetto, G.; Fleurot, J.; Quintard, M.

    2012-11-01

    Understanding of two-phase flow through porous medium with intense phase change is of interest in many situations, including nuclear, chemical or geophysical applications. Intense boiling occurs when the liquid is injected into a highly superheated medium. Under such conditions, the heat flux extracted by the fluid from the porous medium is mainly governed by the nucleation of bubbles and by the evaporation of thin liquid films. Both configurations are possible, depending on local flow conditions and on the ratio of bubble size to pore size. The present study is motivated by the safety evaluation of light water nuclear reactors in case of a severe accident scenario, such as the one that happened in Fukushima Dai-ichi plant in March, 2011. If water sources are not available for a long period of time, the reactor core heats up due to the residual power and eventually becomes significantly damaged due to intense oxidation of metals and fragmentation of fuel rods resulting in the formation of a porous medium where the particles have a characteristic length-scale of 1 to 5 mm. The coolability of the porous medium will depend on the water flow rate which can enter the medium under the available driving head and on the geometrical features of the porous matrix (average pore size, porosity). Therefore, it is of high interest to evaluate the conditions for which the injection of water in such porous medium is likely to stop the progression of the accident. The present paper addresses the issue of modelling two-phase flow and heat transfers in a porous medium initially dry, where water is injected. The medium is initially at a temperature well above the saturation temperature of water. In a first part, a summary of existing knowledge is provided, showing the scarcity of models and experimental data. In a second part, new experimental results obtained in an IRSN facility are analysed. The experiment consists in a bed of steel particles that are heated up to 700

  5. Monotropic smectic A to double layer smectic C transition of biphenyl containing liquid crystal acetylene

    Institute of Scientific and Technical Information of China (English)

    Zhen Qiang Yu; Cai Zhen Zhu; Zhe Zhang; Jian Hong Liu; Jacky W.Y. Lam; Ben Zhong Tang

    2011-01-01

    5-[(4'-Heptoxy-4-biphenylyl)carbonyloxy]-l-pentyne (A-3, 7) was synthesized and the phase structures and transitions were investigated by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), polarized light microscopy (PLM) and the molecular packing in the crystal and liquid crystalline phases were simulated by molecular dynamic simulation. The results showed that the sample formed thermodynamically metastable SmA and SmC2 phases before crystallized during cooling and the crystal phase directly transformed into isotropic phase during heating.

  6. Optical control of graphene plasmon using liquid crystal layer 29K New One

    Science.gov (United States)

    2017-03-01

    the basic research and establishes possible optical ways to control the surface plasmon polariton in graphene layer. A system comprises the graphene...Project main idea The project is devoted to the basic research and establishes possible optical ways to control the surface plasmon polariton in...H H E     (5) Demanding the boundary conditions (5) to be satisfied we obtain after some algebraic transformations a dispersion equation for

  7. Unsteady MHD convection in a flat horizontal layer of liquid with free boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Antimirov, M.Ya.; Liyepinya, V.R.

    1977-10-01

    A complete solution is produced to the unsteady problem of the convective movement of a conducting fluid in a flat horizontal layer with free boundaries (in its linear statement) when an external magnetic field is present. Analysis of the solution produced allows the stability of motion to be studied and, furthermore, permits unambiguous determination of steady motion at the boundary of stability by a passage to the limit as t ..-->.. infinity in the unsteady solution at the critical Rayleigh number. 3 references.

  8. Lubrication theory applied to the convergent flows of two stacked liquid layers

    Energy Technology Data Exchange (ETDEWEB)

    Gratton, Julio [INFIP-CONICET, Dpto. de Fisica, FCEyN, UBA, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina); Perazzo, Carlos Alberto, E-mail: jgratton@tinfip.lfp.uba.ar, E-mail: perazzo@favaloro.edu.ar [Universidad Favaloro and CONICET, Solis 453, 1078 Buenos Aires (Argentina)

    2011-05-01

    With the aim of describing the mountain building process, we have previously applied the lubrication approximation to obtain the evolution equations of the problem of two stacked layers of viscous fluids with different densities and different viscosities. The lubrication approximation is a perturbation method where the small parameter is the aspect ratio (thickness/lenght) of the current. This approximation is widely used to study the slow flow of one layer of a viscous fluid, but it is not well known under which conditions it can be applied in more general settings. Here we analyze in detail the assumptions needed to apply the lubrication theory to study the flow of two stacked viscous fluid layers. We employ the same perturbation method and we found that, besides the usual conditions (low Reynolds number and gentle slope), we must require that the viscosity and density ratios are of the order of unity. These requirements determine the range of validity of the equations of our model of the mountain building.

  9. Origin of weak layer contraction in de Vries smectic liquid crystals

    Science.gov (United States)

    Agra-Kooijman, Dena M.; Yoon, HyungGuen; Dey, Sonal; Kumar, Satyendra

    2014-03-01

    Structural investigations of the de Vries smectic-A (SmA) and smectic-C (SmC) phases of four mesogens containing a trisiloxane end segment reveal a linear molecular conformation in the SmA phase and a bent conformation resembling a hockey stick in the SmC phase. The siloxane and the hydrocarbon parts of the molecule tilt at different angles relative to the smectic layer normal and are oriented along different directions. For the compounds investigated, the shape of orientational distribution function (ODF) is found to be sugarloaf shaped and not the widely expected volcano like with positive orientational order parameters: ⟨P2⟩ = 0.53-0.78, ⟨P4⟩ = 0.14-0.45, and ⟨P6⟩˜0.10. The increase in the effective molecular length, and consequently in the smectic layer spacing caused by reduced fluctuations and the corresponding narrowing of the ODF, counteracts the effect of molecular tilt and significantly reduces the SmC layer contraction. Maximum tilt of the hydrocarbon part of the molecule lies between approximately 18° and 25° and between 6° and 12° for the siloxane part. The critical exponent of the tilt order parameter, β˜0.25, is in agreement with tricritical behavior at the SmA-SmC transition for two compounds and has lower value for first-order transition in the other compounds with finite enthalpy of transition.

  10. X-ray and Electrochemical Impedance Spectroscopy Diagnostic Investigations of Liquid Water in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

    Science.gov (United States)

    Antonacci, Patrick

    In this thesis, electrochemical impedance spectroscopy (EIS) and synchrotron x-ray radiography were utilized to characterize the impact of liquid water distributions in polymer electrolyte membrane fuel cell (PEMFC) gas diffusion layers (GDLs) on fuel cell performance. These diagnostic techniques were used to quantify the effects of liquid water visualized on equivalent resistances measured through EIS. The effects of varying the thickness of the microporous layer (MPL) of GDLs were studied using these diagnostic techniques. In a first study on the feasibility of this methodology, two fuel cell cases with a 100 microm-thick and a 150 microm-thick MPL were compared under constant current density operation. In a second study with 10, 30, 50, and 100 microm-thick MPLs, the liquid water in the cathode substrate was demonstrated to affect mass transport resistance, while the liquid water content in the anode (from back diffusion) affected membrane hydration, evidenced through ohmic resistance measurements.

  11. The bridge between thin layer chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry: The realization of liquid thin layer chromatography-mass spectrometry (LTLC-MS).

    Science.gov (United States)

    Li, Yafeng; Wang, Jianing; Zhan, Lingpeng; Wleklinski, Michael; Wang, Jiyun; Xiong, Caiqiao; Liu, Huihui; Zhou, Yueming; Nie, Zongxiu

    2016-08-19

    The combination of thin layer chromatography (TLC) and mass spectrometry (MS) has been studied for decades, but for most cases MS detection is done after TLC separation is finished. Here, an online simultaneous TLC-MS analysis system, liquid thin layer chromatography-mass spectrometry (LTLC-MS), is developed which successfully synchronize TLC separation process and MS detection process like GC-MS and HPLC-MS do. And there's no need to use specially designed TLC, just regular TLC plates are enough. LTLC-MS method is composed of a newly developed ambient ionization method, glow discharge-matrix assisted infrared desorption ionization (GD-MAIRDI), and forced-flow TLC (FFTLC) technique, which guarantees the MS detection process does not disturb the TLC separation process throughout the whole analysis. The whole LTLC-MS analysis only need two steps and less than 15min. Mixtures as well as the two main components of a pain relief pills have been successfully analyzed by LTLC-MS. This proof of concept study opens up new possibilities of combining TLC with MS, and will further broaden the application abilities of TLC.

  12. Reflection and Transmission of the Level Step to the Waves in a Linear and Continuous Layer Liquid

    Institute of Scientific and Technical Information of China (English)

    TAN Xiao-ning; LI Qiang

    2006-01-01

    The reflection and transmission of the level step to the water waves in the linear and continuous layer liquid were studied in this paper. Based on the matching method of the eigenfunction and a Boussinesq approximation, the analytical expression of the diffraction was obtained and the computing methods of the reflection and transmission energy of the level step were proposed. For the incident wave with a frequency greater than that of the flotage, there is only one mode of plane traveling wave in the flow field. In the range of this greater frequency, the linear and continuous delamination effect will affect the reflection and transmission energy of the floating rectangular box. When the frequency of the incident wave is less than the flotage frequency, the energy of the plane traveling wave with infinite modes in the flow field will change into the energy of different modes for each incident wave of different modes.

  13. The study of The study of the influence of temperature on surfactants – polyethylene glycol layers The study of the influence of temperature on surfactants – polyethylene glycol layers on liquid-gas interface liquid-gas interfacethe influence of temperature on surfactants – polyethylene glycol layers on liquid-gas interfaceThe study of the influence of temperature on surfactants – polyethylene glycol layers on liquid-gas interface

    Directory of Open Access Journals (Sweden)

    Seryk Boloshaan

    2015-03-01

    Full Text Available The surface tension of compositions consisting of nonionic polyethylene glycol and surface active substances of different nature and influence of temperatures on properties of their adsorption layers were studied. To be taken into account the basics of classical chemical thermodynamics and colloidal chemistry, the thermodynamic parameters were determined for the adsorption of glycol, cetyl pyridinium bromide, Tween- 80 and sodium dodecyl sulfate. Adsorption speed was valuated By Kinetic curves of a liquid /gas interfaces. As a surfactants were taken the anionic surfactant – sodium dodecylsulphate, cationic surfactant cetylpyridinium bromide and nonionic Tween-80. The reason of using nonionic polyethyleneglycol as polymer is that the polymer is not toxic, biodegradable and it has no harm to the human body. That is why they are largely used in food industry, pharmaceutics, cosmetics and household chemical products.

  14. Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

    OpenAIRE

    Dietmar Gerteisen; Robert Alink

    2013-01-01

    In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM) fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL) structure and the transitions from the paths to the subsequent ...

  15. Photorefractive Effect of a Liquid Crystal Cell with a ZnO Nanorod Doped in Only One PVA Layer

    Institute of Scientific and Technical Information of China (English)

    GUO Yu-Bing; CHEN Yong-Hai; XIANG Ying; QU Sheng-Chun; WANG Zhan-Guo

    2011-01-01

    We observe obviously different diffraction efficiencies with forward and reverse dc voltages in a forced-light-scattering (FLS) experiment for a cell with ZnO nanorod doped in only one poly (vinyl alcohol) (PVA) layer. When a dc voltage with a positive pole on the ZnO nanorod doped side is applied, the excited charge carriers primarily move along the transverse direction, which results in a higher diffraction efficiency. Conversely, when the dc voltage with a negative pole on the ZnO nanorod doped side is applied, the excited charge carriers primarily move along the longitudinal direction, which leads to a lower diffraction efficiency. A largest diffraction efficiency of about 9% is achieved in the ZnO nanorod doped liquid crystal cell.%@@ We observe obviously different diffraction efficiencies with forward and reverse do voltages in a forced-light-scattering(FLS)experiment for a cell with ZnO nanorod doped in only one poly(vinyl alcohol)(PVA)layer.When a do voltage with a positive pole on the ZnO nanorod doped side is applied,the excited charge carriers primarily move along the transverse direction,which results in a higher diffraction efficiency.Conversely,when the do voltage with a negative pole on the ZnO nanorod doped side is applied,the excited charge carriers primarily move along the longitudinal direction,which leads to a lower diffraction efficiency.A largest diffraction efficiency of about 9%is achieved in the ZnO nanorod doped liquid crystal cell.

  16. Direct nanomechanical measurement of layer thickness and compressibility of smectic liquid crystals.

    Science.gov (United States)

    Carbone, Giovanni; Zappone, Bruno; Barberi, Riccardo; Bartolino, Roberto; Musevic, Igor

    2011-05-01

    Using an atomic force microscope (AFM) we confined a smectic-A liquid crystal (LC) between a flat glass plate and a 10-μm glass sphere attached to the free end of the AFM cantilever. Both surfaces were treated with a surfactant that induces normal alignment of the LC molecules. We measured the force F acting on the cantilever while varying the plate-sphere distance D with subnanometer precision. For D thickness a(0) and compressibility modulus B. Compared to other techniques used to determine a(0) and B, AFM measurements are faster and require a much smaller amount (microliters) of LC. Moreover, they are based on purely mechanical deformations of the LC structure and do not require any static or radiative electromagnetic field.

  17. Influence of liquid medium with different absorption and its layer thickness on bovine bone tibia ablation induced by CO2 laser

    Science.gov (United States)

    Li, Xuwei; Chen, Chuanguo; Zhang, Xianzeng; Zhan, Zhenlin; Xie, Shusen

    2014-11-01

    Liquid-assisted laser ablation has been investigated in laser surface cleaning, laser osteotomy, and dental tissue ablation. However, the actual mechanism of liquid-assisted ablation is not clear yet. The purpose of this study was to investigate the influence of liquid medium with different absorption and the liquid thickness on laser ablation efficiency. A pulsed CO2 laser was employed to ablate bovine bone tibia under liquid layer which varied from 0.6 mm to 2 mm. The applied pulse power level was set at 5 w and each crater was produced with six laser pulses. The results showed that the ablation cross-section area produced with various levels of pure water thickness (0.6, 0.8, 1 and 2 mm)were lower than under ink, and the ablation depth gradually decreased as the water layer becoming thicker. The biggest cross-section area in liquid thickness of ink was 0.8mm, but as the layer thicker than 0.8 mm the ablation depth decreased suddenly. There was thermal damage seen on samples in all of the groups, but less in pure water.

  18. Fundamental aspects of electric double layer force-distance measurements at liquid-solid interfaces using atomic force microscopy.

    Science.gov (United States)

    Black, Jennifer M; Zhu, Mengyang; Zhang, Pengfei; Unocic, Raymond R; Guo, Daqiang; Okatan, M Baris; Dai, Sheng; Cummings, Peter T; Kalinin, Sergei V; Feng, Guang; Balke, Nina

    2016-09-02

    Atomic force microscopy (AFM) force-distance measurements are used to investigate the layered ion structure of Ionic Liquids (ILs) at the mica surface. The effects of various tip properties on the measured force profiles are examined and reveal that the measured ion position is independent of tip properties, while the tip radius affects the forces required to break through the ion layers as well as the adhesion force. Force data is collected for different ILs and directly compared with interfacial ion density profiles predicted by molecular dynamics. Through this comparison it is concluded that AFM force measurements are sensitive to the position of the ion with the larger volume and mass, suggesting that ion selectivity in force-distance measurements are related to excluded volume effects and not to electrostatic or chemical interactions between ions and AFM tip. The comparison also revealed that at distances greater than 1 nm the system maintains overall electroneutrality between the AFM tip and sample, while at smaller distances other forces (e.g., van der waals interactions) dominate and electroneutrality is no longer maintained.

  19. Fundamental aspects of electric double layer force-distance measurements at liquid-solid interfaces using atomic force microscopy

    Science.gov (United States)

    Black, Jennifer M.; Zhu, Mengyang; Zhang, Pengfei; Unocic, Raymond R.; Guo, Daqiang; Okatan, M. Baris; Dai, Sheng; Cummings, Peter T.; Kalinin, Sergei V.; Feng, Guang; Balke, Nina

    2016-01-01

    Atomic force microscopy (AFM) force-distance measurements are used to investigate the layered ion structure of Ionic Liquids (ILs) at the mica surface. The effects of various tip properties on the measured force profiles are examined and reveal that the measured ion position is independent of tip properties, while the tip radius affects the forces required to break through the ion layers as well as the adhesion force. Force data is collected for different ILs and directly compared with interfacial ion density profiles predicted by molecular dynamics. Through this comparison it is concluded that AFM force measurements are sensitive to the position of the ion with the larger volume and mass, suggesting that ion selectivity in force-distance measurements are related to excluded volume effects and not to electrostatic or chemical interactions between ions and AFM tip. The comparison also revealed that at distances greater than 1 nm the system maintains overall electroneutrality between the AFM tip and sample, while at smaller distances other forces (e.g., van der waals interactions) dominate and electroneutrality is no longer maintained. PMID:27587276

  20. Modeling of low convergence liquid layer wetted foam implosions at the National Ignition Facility

    Science.gov (United States)

    Yi, S. A.; Olson, R. E.; Yin, L.; Wilson, D. C.; Herrmann, H. W.; Zylstra, A. B.; Haines, B. M.; Peterson, R. R.; Bradley, P. A.; Shah, R. C.; Kline, J. L.; Leeper, R. J.; Batha, S. H.; Milovich, J. L.; Berzak Hopkins, L. F.; Ho, D. D.; Meezan, N. B.

    2016-10-01

    A new platform has been developed that allows for lower convergence ratio implosions (CR 15) than is possible with traditional DT ice layered capsules (CR 30). We present HYDRA simulation models of the first low convergence DT implosions on NIF utilizing the wetted foam platform. When tuned to match the observed bangtime and hotspot symmetry, our rad-hydro models agree well with many experimental observables. In particular, the inferred hotspot density and pressure are consistent with simulations, and our modeled burn widths are in better relative agreement with the data than in high convergence implosions. The observed neutron yields are approximately 60-70% of postshot calculations. These results indicate that at a reduced convergence ratio CR 15 the hotspot formation process is well modeled by our simulations. This work was performed under the auspices of the U.S. DOE by the LANS, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396.

  1. Surface wave characteristics in a micropolar transversely isotropic halfspace underlying an inviscid liquid layer

    Directory of Open Access Journals (Sweden)

    Gupta R.R.

    2014-02-01

    Full Text Available The present investigation deals with the propagation of waves in a micropolar transversely isotropic half space with an overlying inviscid fluid layer. Effects of fluid loading and anisotropy on the phase velocity, attenuation coefficient, specific loss and relative frequency shift. Finally, a numerical solution was carried out for aluminium epoxy material and the computer simulated results for the phase velocity, attenuation coefficient, specific loss and relative frequency shift are presented graphically. A particular case for the propagation of Rayleigh waves in a micropolar transversely isotropic half-space is deduced and dispersion curves are plotted for the same as functions of the wave number. An amplitude of displacements and microrotation together with the path of surface particles are also calculated for the propagation of Rayleigh waves in the latter case

  2. A Novel Strategy for Simulating the Main Fractionator of Delayed Cokers by Separating the De-superheating Process

    Institute of Scientific and Technical Information of China (English)

    LEI Yang; ZHANG Bingjian; HOU Xiaoqiong; CHEN Qinglin

    2013-01-01

    Delayed coking is an important process in refinery to convert heavy residue oils from crude distillation units (CDUs) and fluid catalytic cracking units (FCCUs) into dry gas,liquefied petroleum gas (LPG),gasoline,diesel,gas oils and cokes.The main fractionator,separating superheating reaction vapors from the coke drums into lighter oil products,involves a de-superheating section and a rectifying section,and couldn't be simulated as a whole column directly because of non-equilibrium in the de-superheating section.It is very important to correctly simulate the main fractionator for operational parameter and energy-use optimization of delayed cokers.This paper discusses the principle of de-superheating processes,and then proposes a new simulation strategy.Some key issues such as composition prediction of the reaction vapors,selection of thermodynamic methods,estimation of tray efficiency,etc.are discussed.The proposed simulation approach is applied to two industrial delayed cokers with typical technological processes in a Chinese refinery by using PRO/II.The simulation results obtained are well consistent with the actual operation data,which indicates that the presented approach is suitable to simulate the main fractionators of delayed cokers or other distillation columns consisting of de-superheating sections and rectifying sections.

  3. Implementation and analysis of an autostereoscopic display using multiple liquid crystal layers

    Science.gov (United States)

    Gotoda, Hironobu

    2012-03-01

    Multilayer displays are constructed by stacking multiple liquid crystal panels along with a pair of polarizers and a light source. Previous theoretical analyses have shown that such a display could exhibit the light field of a 3D scene if the panels in the display are properly controlled. In this study, we present an implementation of a monochromatic multilayer display using IPS-LCD panels, and report that a reasonable approximation of the light field is actually observed from the display. A major obstacle to constructing a multilayer display is the complexity of optical properties of LCD panels. Since an accurate analytic representation of panels' behavior is difficult to obtain, we have developed an approximate model specific to IPS-LCD cells, using which our implementation is built. We then evaluate the quality of the light field observed from the prototype implementation by examining the images photographed at several camera positions. The results show geometrically correct views are observable from the display within the viewing angle of 30 degrees.

  4. Shape optimization of a sheet swimming over a thin liquid layer

    Energy Technology Data Exchange (ETDEWEB)

    Wilkening, J.; Hosoi, A.E.

    2008-12-10

    Motivated by the propulsion mechanisms adopted by gastropods, annelids and other invertebrates, we consider shape optimization of a flexible sheet that moves by propagating deformation waves along its body. The self-propelled sheet is separated from a rigid substrate by a thin layer of viscous Newtonian fluid. We use a lubrication approximation to model the dynamics and derive the relevant Euler-Lagrange equations to simultaneously optimize swimming speed, efficiency and fluid loss. We find that as the parameters controlling these quantities approach critical values, the optimal solutions become singular in a self-similar fashion and sometimes leave the realm of validity of the lubrication model. We explore these singular limits by computing higher order corrections to the zeroth order theory and find that wave profiles that develop cusp-like singularities are appropriately penalized, yielding non-singular optimal solutions. These corrections are themselves validated by comparison with finite element solutions of the full Stokes equations, and, to the extent possible, using recent rigorous a-priori error bounds.

  5. Surface characterization and orientation interaction between diamond- like carbon layer structure and dimeric liquid crystals

    Science.gov (United States)

    Naradikian, H.; Petrov, M.; Katranchev, B.; Milenov, T.; Tinchev, S.

    2017-01-01

    Diamond-like carbon (DLC) and amorphous carbon films are very promising type of semiconductor materials. Depending on the hybridization sp2/sp3 ratio, the material’s band gap varies between 0.8 and 3 eV. Moreover carbon films possess different interesting for practice properties: comparable to the Silicon, Diamond like structure has 22-time better thermal conductivity etc. Here we present one type of implementation of such type nanostructure. That is one attempt for orientation of dimeric LC by using of pre-deposited DLC layer with different ratio of sp2/sp3 hybridized carbon content. It could be expected a pronounced π1-π2interaction between s and p orbital levels on the surface and the dimeric ring of LC. We present comparison of surface anchoring strengths of both orientation inter-surfaces DLC/dimeric LC and single wall carbon nanotubes (SWCNT)/dimeric LC. The mechanism of interaction of dimeric LC and activated surfaces with DLC or SWCNT will be discussed. In both cases we have π-π interaction, which in combination with hydrogen bonding, typical for the dimeric LCs, influence the LC alignment. The Raman spectroscopy data evidenced the presence of charge transfer between contacting hexagonal rings of DLC and the C = O groups of the LC molecules.

  6. Robust pressure sensor for measurements in boundary layers of liquid fluids with medium total pressures

    Science.gov (United States)

    Beutel, T.; Ferreira, N.; Leester-Schädel, M.; Büttgenbach, S.

    2011-06-01

    In this work, the latest results of the design, fabrication and characterization of a new MEMS piezoresistive pressure sensor are presented. It is made of silicon using a boron diffusion process to create piezoresistors. Significant changes in the layout as well as in the micro-fabrication process have been made, e.g. anodic bonding of a Pyrex cover on the backside. These lead to a very precise pressure sensor, which is tailor made for high dynamic measurements in fluids with a total pressure up to 4 bar. This new piezoresistive pressure sensor has been developed in order to meet the special requirements of measurements in fluid mechanics, particularly with regard to the non-intrusive nature of the sensor. The sensor development, starting with the simulation of mechanical stresses within the diaphragm is described. These calculations have lead to an optimized placement of the piezoresistors in order to achieve a maximum sensitivity. The result of this work is a sensor which has well known properties. Important parameters including sensitivity, resonance frequency and maximum load are described precisely. These are necessary to enable new measurements in the boundary layer of fluids. The experiments and the initial results, e.g. its linearity and its dynamic capability are demonstrated in several figures.

  7. Fracture Modes in Curved Brittle Layers Subject to Concentrated Cyclic Loading in Liquid Environments.

    Science.gov (United States)

    Kim, Jae-Won; Thompson, Van P; Rekow, E Dianne; Jung, Yeon-Gil; Zhang, Yu

    2009-03-01

    Damage response of brittle curved structures subject to cyclic Hertzian indentation was investigated. Specimens were fabricated by bisecting cylindrical quartz glass hollow tubes. The resulting hemi-cylindrical glass shells were bonded internally and at the edges to polymeric supporting structures and loaded axially in water on the outer circumference with a spherical tungsten carbide indenter. Critical loads and number of cycles to initiate and propagate near-contact cone cracks and far-field flexure radial cracks to failure were recorded. Flat quartz glass plates on polymer substrates were tested as a control group. Our findings showed that cone cracks form at lower loads, and can propagate through the quartz layer to the quartz/polymer interface at lower number of cycles, in the curved specimens relative to their flat counterparts. Flexural radial cracks require a higher load to initiate in the curved specimens relative to flat structures. These radial cracks can propagate rapidly to the margins, the flat edges of the bisecting plane, under cyclic loading at relatively low loads, owing to mechanical fatigue and a greater spatial range of tensile stresses in curved structures.

  8. Improvement of the phase transition homogeneity of superheated superconducting tin granules

    CERN Document Server

    Calatroni, Sergio; Czapek, G; Ebert, T R; Hasenbalg, F; Hauser, M G; Janos, S; Kainer, K U; Knoop, K M; Moser, U; Palmieri, V G; Pretzl, Klaus P; Sahli, B; Sgobba, Stefano; Vollenberg, W; Wyss, C

    2000-01-01

    A considerably improved phase transition homogeneity was observed with superheated superconducting Sn spheres as a result of laser melting and fast cooling. These spheres exhibited a very homogeneous phase transition behaviour independent of the orientation of the spheres with respect to the direction of the external magnetic field. Compared to previously untreated Sn spheres the spread of the phase transition boundaries was reduced by almost an order of magnitude. In addition, we studied mass production of Sn structures using vacuum evaporation and deposition. First encouraging results are reported. (7 refs).

  9. Heat Transfer of Condensation in Smooth Round Tube from Superheated Vapor

    OpenAIRE

    Xiao, Jiange; Hrnjak, Pega

    2016-01-01

    Heat transfer of R134a condensing in a horizontal smooth round tube with 6.1 mm inner diameter is invested in this study. Experimental results on the heat transfer coefficient (HTC) with mass flux from 50 to 200 kg m-2 s-1 and heat flux from 5 to 15 kW m-2 are provided. Heat transfer behavior is compared between condensing superheated (CSH) region and two-phase (TP) region. Experimental result shows that in TP region, higher mass flux results in higher HTC while heat flux does not affect HTC....

  10. Superheating and Homogeneous Single Bubble Nucleation in a Solid-State Nanopore

    Science.gov (United States)

    Nagashima, Gaku; Levine, Edlyn V.; Hoogerheide, David P.; Burns, Michael M.; Golovchenko, Jene A.

    2014-01-01

    We demonstrate extreme superheating and single bubble nucleation in an electrolyte solution within a nanopore in a thin silicon nitride membrane. The high temperatures are achieved by Joule heating from a highly focused ionic current induced to flow through the pore by modest voltage biases. Conductance, nucleation, and bubble evolution are monitored electronically and optically. Temperatures near the thermodynamic limit of superheat are achieved just before bubble nucleation with the system at atmospheric pressure. Bubble nucleation is homogeneous and highly reproducible. This nanopore approach more generally suggests broad application to the excitation, detection, and characterization of highly metastable states of matter. PMID:25062192

  11. First Dark Matter Limits from a Large-Mass, Low-Background Superheated Droplet Detector

    CERN Document Server

    Collar, J.I.; Girard, T.A.; Limagne, D.; Miley, H.S.; Waysand, G.

    2000-01-01

    We report on the fabrication aspects and calibration of the first large active mass ($\\sim15$ g) modules of SIMPLE, a search for particle dark matter using Superheated Droplet Detectors (SDDs). While still limited by the statistical uncertainty of the small data sample on hand, the first weeks of operation in the new underground laboratory of Rustrel-Pays d'Apt already provide a sensitivity to axially-coupled Weakly Interacting Massive Particles (WIMPs) competitive with leading experiments, confirming SDDs as a convenient, low-cost alternative for WIMP detection.

  12. Machine Learning Method Applied in Readout System of Superheated Droplet Detector

    Science.gov (United States)

    Liu, Yi; Sullivan, Clair Julia; d'Errico, Francesco

    2017-07-01

    Direct readability is one advantage of superheated droplet detectors in neutron dosimetry. Utilizing such a distinct characteristic, an imaging readout system analyzes image of the detector for neutron dose readout. To improve the accuracy and precision of algorithms in the imaging readout system, machine learning algorithms were developed. Deep learning neural network and support vector machine algorithms are applied and compared with generally used Hough transform and curvature analysis methods. The machine learning methods showed a much higher accuracy and better precision in recognizing circular gas bubbles.

  13. Improvement of the phase transition homogeneity of superheated superconducting tin granules

    Energy Technology Data Exchange (ETDEWEB)

    Calatroni, S.; Casalbuoni, S. E-mail: sara@lhc.lhep.unibe.ch; Czapek, G.; Ebert, T.; Hasenbalg, F.; Hauser, M.; Janos, S.; Kainer, K.U.; Knoop, K.M.; Moser, U.; Palmieri, V.G.; Pretzl, K.; Sahli, B.; Sgobba, S.; Vollenberg, W.; Wyss, Ch.P

    2000-04-07

    A considerably improved phase transition homogeneity was observed with superheated superconducting Sn spheres as a result of laser melting and fast cooling. These spheres exhibited a very homogeneous phase transition behaviour independent of the orientation of the spheres with respect to the direction of the external magnetic field. Compared to previously untreated Sn spheres the spread of the phase transition boundaries was reduced by almost an order of magnitude. In addition, we studied mass production of Sn structures using vacuum evaporation and deposition. First encouraging results are reported.

  14. Extraction of amino acids from soils and sediments with superheated water

    Science.gov (United States)

    Cheng, C. N.; Ponnamperuma, C.

    1974-01-01

    A method of extraction for amino acids from soils and sediments involving superheated water has been investigated. About 75-97 per cent of the amino acids contained in four soils of a soil profile from Illinois were extracted by this method. Deep penetration of water into soil aggregates and partial hydrolysis of peptide bonds during this extraction by water at high temperature are likely mechanisms responsible for the release of amino acids from samples. This extraction method does not require subsequent desalting treatments when analyses are carried out with an ion-exchange amino acid analyzer.

  15. Bubble dynamics during the non-isothermal degassing of liquids. Exploiting microgravity conditions.

    Science.gov (United States)

    Kostoglou, Margaritis; Karapantsios, Thodoris D

    2007-10-31

    This work reviews the up to date state of understanding of dynamic phenomena occurring when gas bubbles grow over submerged heated surfaces. Gas bubbles are produced on hot surfaces because the adjacent liquid layers become superheated causing local desorption of dissolved gases while the liquid far afield remains at low temperatures. Non-isothermal degassing is a very complex process combining heat and mass transport coupled with momentum exchange between the two phases. Difficulties due to buoyancy effects on gas bubbles as well as natural convection of hot liquid layers hindered its thorough investigation in terrestrial conditions and only recent microgravity data allowed serious progress to be made. To reduce the complexity, gas bubble growth on a heated wall was studied here separately from bubble lateral motion and coalescence. A complete mathematical formulation was provided but given the inability to solve the problem numerically with the present resources, a series of approximate solutions were attempted. The comparison between experimental observations and theoretical predictions revealed useful information regarding the governing mechanisms of bubble growth.

  16. Vibrational Stark Effect to Probe the Electric-Double Layer of the Ionic Liquid-Metal Electrodes

    Science.gov (United States)

    Garcia Rey, Natalia; Moore, Alexander Knight; Toyouchi, Shuichi; Dlott, Dana

    2017-06-01

    Vibrational sum frequency generation (VSFG) spectroscopy is used to study the effect of room temperature ionic liquids (RTILs) in situ at the electrical double layer (EDL). RTILs have been recognized as electrolytes without solvent for applications in batteries, supercapacitors and electrodeposition^{1}. The molecular response of the RTIL in the EDL affects the performance of these devices. We use the vibrational Stark effect on CO as a probe to detect the changes in the electric field affected by the RTIL across the EDL on metal electrodes. The Stark effect is a shift in the frequency in response to an externally applied electric field and also influenced by the surrounding electrolyte and electrode^{2}. The CO Stark shift is monitored by the CO-VSFG spectra on Pt or Ag in a range of different imidazolium-based RTILs electrolytes, where their composition is tuned by exchanging the anion, the cation or the imidazolium functional group. We study the free induction decay (FID)^{3} of the CO to monitor how the RTIL structure and composition affect the vibrational relaxation of the CO. Combining the CO vibrational Stark effect and the FID allow us to understand how the RTIL electrochemical response, molecular orientation response and collective relaxation affect the potential drop of the electric field across the EDL, and, in turn, how determines the electrical capacitance or reactivity of the electrolyte/electrode interface. ^{1}Fedorov, M. V.; Kornyshev, A. A., Ionic Liquids at Electrified Interfaces. Chem. Rev. 2014, 114, 2978-3036. ^{2} (a) Lambert, D. K., Vibrational Stark Effect of Adsorbates at Electrochemical Interfaces. Electrochim. Acta 1996, 41, 623-630. (b) Oklejas, V.; Sjostrom, C.; Harris, J. M., SERS Detection of the Vibrational Stark Effect from Nitrile-Terminated SAMs to Probe Electric Fields in the Diffuse Double-Layer. J. Am. Chem. Soc. 2002, 124, 2408-2409. ^{3}Symonds, J. P. R.; Arnolds, H.; Zhang, V. L.; Fukutani, K.; King, D. A

  17. Electro-optical response of polymer-dispersed liquid crystal single layers of large nematic droplets oriented by rubbed teflon nanolayers

    Science.gov (United States)

    Marinov, Y. G.; Hadjichristov, G. B.; Petrov, A. G.; Marino, S.; Versace, C.; Scaramuzza, N.

    2013-02-01

    The surface orienting effect of rubbed teflon nanolayers on the morphology and electro-optical (EO) response of polymer-dispersed liquid crystal (PDLC) single layers of large nematic droplets was studied experimentally. In PDLC composites of the nematic liquid crystal (LC) E7 and NOA65 polymer, single droplets of LC with diameters as larger as 10 μm were confined in layers with a thickness of 10 μm, and the nematic director field was efficiently modified by nanostructuring teflon rubbing of the glass plates of the PDLC cell. For layered PDLCs arranged and oriented in this way, the modulated EO response by the dielectric oscillations of the nematic director exhibits a selective amplitude-frequency modulation controllable by both temperature and voltage applied, and is simply related to the LC droplet size. That may be of practical interest for PDLC-based modulators operating in the infrasound frequency range.

  18. Sub-micrometer dropwise condensation under superheated and rarefied vapor condition.

    Science.gov (United States)

    Anand, Sushant; Son, Sang Young

    2010-11-16

    Phase change accompanying conversion of a saturated or superheated vapor in the presence of subcooled surfaces is one of the most common occurring phenomena in nature. The mode of phase change that follows such a transformation is dependent upon surface properties such as contact angle and thermodynamic conditions of the system. In present studies, an experimental approach is used to study the physics behind droplet growth on a partially wet surface. Superheated vapor at low pressures of 4-5 Torr was condensed on subcooled silicon surface with a static contact angle of 60° in the absence of noncondensable gases, and the condensation process was monitored using environmental scanning electron microscopy (ESEM) with sub-microscopic spatial resolution. The condensation process was analyzed in the form of size growth of isolated droplets before a coalescence event ended the regime of single droplet growth. Droplet growth obtained as a function of time reveals that the rate of growth decreases as the droplet increases in size. This behavior is indicative of an overall droplet growth law existing over larger time scales for which the current observations in their brief time intervals could be fitted. A theoretical model based on kinetic theory further support the experimental observations indicating a mechanism where growth occurs by interfacial mass transport directly on condensing droplet surface. Evidence was also found that establishes the presence of sub-microscopic droplets nucleating and growing between microscopic droplets for the partially wetting case.

  19. Effect of Superheated Steam Treatment on Changes in Moisture Content and Colour Properties of Coconut Slices

    Directory of Open Access Journals (Sweden)

    Mah Sook Yun

    2015-03-01

    Full Text Available Drying is one of the methods to preserve the quality and prolong the shelf life of food. Coconut meat was sliced and dried using superheated steam oven at 140°C, 160°C and 180°C. Drying was carried out at different drying time (5, 10, 15, 20, 25 and 30 minutes. The effect of drying temperature and time on the moisture content and colour properties (L, a, b and BI of the coconut slices were studied. The temperature and time significantly (p < 0.05 affected the moisture loss and colour values of coconut slices during superheated steam drying. The moisture content decreased with increased drying temperature and time. The values of L decreased with drying temperature and time. The a and b value of coconut slice dried at 140°C decreased initially then increased with time. Coconut slices dried at 160°C had their a values increased up to 20 minutes then decreased and b values increased up to 20 minutes then fluctuated. The a and b values of coconut slices dried at 180°C showed fluctuation. BI values of coconut slices increased with increasing drying time and temperature.

  20. Effect of Superheated Steam Roasting on Radical Scavenging Activity and Phenolic Content of Robusta Coffee Beans

    Directory of Open Access Journals (Sweden)

    Ooi Ee Shan

    2015-04-01

    Full Text Available Robusta coffee is one of the coffee species grown in Malaysia. However, there is little research conducted on Robusta coffee beans as Arabica coffee is more popular among the consumers. Coffee is a rich source of antioxidants, therefore research on antioxidant properties of Robusta coffee beans is important to explore its market value. Nowadays, most of coffee analysis is on conventional roasted coffee which reduces their antioxidant properties. In this study, Robusta coffee beans (Coffea canephora were subjected to superheated steam roasting at 200, 220 and 240 ˚C for 20-40 min to obtain light, medium and dark roast. The effect of different roasting temperature and time on the total phenolic content (TPC and radical scavenging activity (RSA of Robusta coffee bean was investigated. Total phenolic content of coffee brews decreased with the increase of roasting degree due to the degradation of phenolic compounds. The highest phenolic content was found at 220 ˚C for 20 min. Meanwhile, brews extracted from light roasted coffee and medium roasted at 220 ˚C for 20 min showed a maximum scavenging activity than those from green coffee. Brews from dark roasted coffee showed lowest radical scavenging activity and total phenol content. Hence, based on the results from this study, the best superheated steam roasting condition is at 220 ˚C for 20 min (medium roast to achieve a maximum antioxidant activity and highest phenolic content.

  1. Investigation of effects of chemical dosing on fuel consumption in central heating systems with superheated water

    Energy Technology Data Exchange (ETDEWEB)

    Bilen, Kemal [Kirikkale University, Engineering Faculty, Mechanical Engineering Department, Kirikkale (Turkey); email: kemal.bilen92@gmail.com

    2011-07-01

    In Turkey, a significant percentage of energy is consumed by buildings and heating accounts for most of it. These is therefore a need to increase the efficiency of such systems. As a regional heating option, central heating systems with superheated water are preferred and chemical dosing of these systems has become prevalent in recent years. This study analyses the energy and exergy of a superheated water, central heating system operated on natural gas, on a university campus with a population of 15000 people, and investigates the effect of chemical dosing on their efficiencies. The study results showed that the average energy and exergy efficiencies of the system were 92.07% and 62.45%, respectively. The results also demonstrated that there was a 5.21% and 2.74% increase in hourly gas consumption when the dosing concentration was changed from 5 ppm to 101 ppm and 50 ppm to 101 ppm, respectively. It was concluded that for lower fuel consumption, chemical dosing should be avoided.

  2. Differentiation of coloured inks of inkjet printer cartridges by thin layer chromatography and high performance liquid chromatography.

    Science.gov (United States)

    Poon, N L; Ho, S S H; Li, C K

    2005-01-01

    Document examiners are frequently asked to determine whether or not a colour printout has originated from a particular inkjet printer. The printer can rarely be identified unless some unique defects or irregularities of the printer are present on the printout. However, it is possible to decipher the make and/or model of the printer by comparing the ink-profile of the questioned printout with that of a seized inkjet printer cartridge or from one in a database. This paper presents an overview of a systematic approach to characterising and discriminating the inks of different inkjet printer cartridges using thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC) with multi-wavelength ultra-violet/visible (UV/Vis) detection. Ink samples from 23 different inkjet printer cartridges (including originals and substitutes) of different brands and colour printouts, printed by known printers were examined with newly developed chromatographic methods. Subsequently, a database of the ink-profiles was generated. The methods provide a useful tool for discriminating coloured inks in inkjet printer cartridges of different brands.

  3. An ether-functionalised cyclic sulfonium based ionic liquid as an electrolyte for electrochemical double layer capacitors

    Science.gov (United States)

    Neale, Alex R.; Murphy, Sinead; Goodrich, Peter; Schütter, Christoph; Hardacre, Christopher; Passerini, Stefano; Balducci, Andrea; Jacquemin, Johan

    2016-09-01

    A novel cyclic sulfonium cation-based ionic liquid (IL) with an ether-group appendage and the bis{(trifluoromethyl)sulfonyl}imide anion was synthesised and developed for electrochemical double layer capacitor (EDLC) testing. The synthesis and chemical-physical characterisation of the ether-group containing IL is reported in parallel with a similarly sized alkyl-functionalised sulfonium IL. Results of the chemical-physical measurements demonstrate how important transport properties, i.e. viscosity and conductivity, can be promoted through the introduction of the ether-functionality without impeding thermal, chemical or electrochemical stability of the IL. Although the apparent transport properties are improved relative to the alkyl-functionalised analogue, the ether-functionalised sulfonium cation-based IL exhibits moderately high viscosity, and poorer conductivity, when compared to traditional EDLC electrolytes based on organic solvents (propylene carbonate and acetonitrile). Electrochemical testing of the ether-functionalised sulfonium IL was conducted using activated carbon composite electrodes to inspect the performance of the IL as a solvent-free electrolyte for EDLC application. Good cycling stability was achieved over the studied range and the performance was comparable to other solvent-free, IL-based EDLC systems. Nevertheless, limitations of the attainable performance are primarily the result of sluggish transport properties and a restricted operative voltage of the IL, thus highlighting key aspects of this field which require further attention.

  4. Indium oxide thin film prepared by low temperature atomic layer deposition using liquid precursors and ozone oxidant

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W.J. [Department of Materials Science and Engineering, University of Wisconsin Madison, Madison, WI 53706 (United States); Choi, Dong-Won [Division of Materials Science and Engineering, 222 Wangsimni-ro, Seongdong-gu, Hanyang University, Seoul, 133-719 (Korea, Republic of); Park, Jozeph, E-mail: jozeph.park@gmail.com [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Park, Jin-Seong, E-mail: jsparklime@hanyang.ac.kr [Division of Materials Science and Engineering, 222 Wangsimni-ro, Seongdong-gu, Hanyang University, Seoul, 133-719 (Korea, Republic of)

    2015-11-15

    Transparent conducting Indium oxide (InO{sub x}) thin films were deposited by atomic layer deposition at low deposition temperatures below 100 °C. For the comparative study with liquid precursors in low temperature thermal ALD, diethyl[1,1,1-trimethyl-N-(trimethylsilyl)silanaminato]-Indium, [3-(dimethylamino-kN)propyl-kC]dimethyl-Indium, and triethyl indium (TEIn) were used as the In precursors. Ozone was used as the oxidant for all precursors. InO{sub x} films grown using the three precursors all exhibit relatively low electrical resistivity below 10{sup −3} Ω cm at temperatures above 150 °C. Below 100 °C, the lowest resistivity (2 × 10{sup −3} Ω cm) was observed in the films grown with TEIn. The electrical, structural and optical properties were systematically investigated as functions of the deposition temperature and precursors. - Highlights: • InO{sub x} thin films were deposited by ALD at extremely low deposition temperatures below 100 °C. • InO{sub x} films exhibit relatively low electrical resistivity below 10{sup −3} Ω cm at temperatures above 150 °C. • Ozone stimulate the chemical reactions to yield dense indium oxide films at low temperatures.

  5. Liquid-Phase Exfoliation of Graphite into Single- and Few-Layer Graphene with α-Functionalized Alkanes.

    Science.gov (United States)

    Haar, Sébastien; Bruna, Matteo; Lian, Jian Xiang; Tomarchio, Flavia; Olivier, Yoann; Mazzaro, Raffaello; Morandi, Vittorio; Moran, Joseph; Ferrari, Andrea C; Beljonne, David; Ciesielski, Artur; Samorì, Paolo

    2016-07-21

    Graphene has unique physical and chemical properties, making it appealing for a number of applications in optoelectronics, sensing, photonics, composites, and smart coatings, just to cite a few. These require the development of production processes that are inexpensive and up-scalable. These criteria are met in liquid-phase exfoliation (LPE), a technique that can be enhanced when specific organic molecules are used. Here we report the exfoliation of graphite in N-methyl-2-pyrrolidinone, in the presence of heneicosane linear alkanes terminated with different head groups. These molecules act as stabilizing agents during exfoliation. The efficiency of the exfoliation in terms of the concentration of exfoliated single- and few-layer graphene flakes depends on the functional head group determining the strength of the molecular dimerization through dipole-dipole interactions. A thermodynamic analysis is carried out to interpret the impact of the termination group of the alkyl chain on the exfoliation yield. This combines molecular dynamics and molecular mechanics to rationalize the role of functionalized alkanes in the dispersion and stabilization process, which is ultimately attributed to a synergistic effect of the interactions between the molecules, graphene, and the solvent.

  6. A new method for laminar boundary layer transition visualization in flight: Color changes in liquid crystal coatings

    Science.gov (United States)

    Holmes, B. J.; Gall, P. D.; Croom, C. C.; Manuel, G. S.; Kelliher, W. C.

    1986-01-01

    The visualization of laminar to turbulent boundary layer transition plays an important role in flight and wind-tunnel aerodynamic testing of aircraft wing and body surfaces. Visualization can help provide a more complete understanding of both transition location as well as transition modes; without visualization, the transition process can be very difficult to understand. In the past, the most valuable transition visualization methods for flight applications included sublimating chemicals and oil flows. Each method has advantages and limitations. In particular, sublimating chemicals are impractical to use in subsonic applications much above 20,000 feet because of the greatly reduced rates of sublimation at lower temperatures (less than -4 degrees Farenheit). Both oil flow and sublimating chemicals have the disadvantage of providing only one good data point per flight. Thus, for many important flight conditions, transition visualization has not been readily available. This paper discusses a new method for visualizing transition in flight by the use of liquid crystals. The new method overcomes the limitations of past techniques, and provides transition visualization capability throughout almost the entire altitude and speed ranges of virtually all subsonic aircraft flight envelopes. The method also has wide applicability for supersonic transition visualization in flight and for general use in wind tunnel research over wide subsonic and supersonic speed ranges.

  7. Toward uniform and ultrathin carbon layer coating on lithium iron phosphate using liquid carbon dioxide for enhanced electrochemical performance

    Science.gov (United States)

    Hong, Seung-Ah; Kim, Dong Hyun; Chung, Kyung Yoon; Chang, Wonyoung; Yoo, Jibeom; Kim, Jaehoon

    2014-09-01

    In this communication, uniform and ultrathin carbon coating on LiFePO4 (LFP) particles are performed using liquid carbon dioxide (l-CO2)-based free-meniscus coating. The uniform and conformal coverage of the carbon layer on LFP with a thickness of 3.3 nm, and a uniform distribution of carbon on the entire surface of the LFP particle are confirmed. The carbon-coated LFP (C-LFP) with a carbon content of 1.9 wt.% obtained using l-CO2-based coating exhibits a discharge capacity of 169 mAh g-1 at 0.1 C and 71 mAh g-1 at 30 C, while much lower discharge capacity of 146 mAh g-1 at 0.1 C and 17 mAh g-1 at 30 C is observed when C-LFP with an optimized carbon content of 6.0 wt.% is prepared using conventional aqueous-based coating.

  8. PHYSICOCHEMICAL PROPERTY CHANGES AND ENZYMATIC HYDROLYSIS ENHANCEMENT OF OIL PALM EMPTY FRUIT BUNCHES TREATED WITH SUPERHEATED STEAM

    Directory of Open Access Journals (Sweden)

    Ezyana Kamal Bahrin,

    2012-02-01

    Full Text Available The effect of superheated steam treatment on oil palm empty fruit bunches (OPEFB was investigated in terms of physicochemical property changes and enzymatic hydrolysis enhancement. The experimental treatment was carried out at different temperatures (140-210°C and durations (20-90 min. Results showed that as the superheated steam temperature and time increased, the size distribution also changed, resulting in more small particles. Analysis on the surface texture, color, and mechanical properties of the treated OPEFB also showed that significant changes resulted due to the superheated steam treatment. In support to this, Fourier Transform Infrared (FTIR spectroscopy and thermogravimetric (TG analyses showed that solubilization and removal of the hemicelluloses component also took place. As a result of this phenomenon, higher total sugar and glucose yield was achieved once the treated OPEFB was subjected to enzymatic hydrolysis. This suggests that superheated steam treatment could enhance OPEFB structure degradation for the preparation of a suitable substrate in order to produce a higher glucose yield in the enzymatic hydrolysis process.

  9. Arabidopsis thaliana Polar Glycerolipid Profiling by Thin Layer Chromatography (TLC) Coupled with Gas-Liquid Chromatography (GLC)

    Science.gov (United States)

    Wang, Zhen; Benning, Christoph

    2011-01-01

    Biological membranes separate cells from the environment. From a single cell to multicellular plants and animals, glycerolipids, such as phosphatidylcholine or phosphatidylethanolamine, form bilayer membranes which act as both boundaries and interfaces for chemical exchange between cells and their surroundings. Unlike animals, plant cells have a special organelle for photosynthesis, the chloroplast. The intricate membrane system of the chloroplast contains unique glycerolipids, namely glycolipids lacking phosphorus: monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG)4. The roles of these lipids are beyond simply structural. These glycolipids and other glycerolipids were found in the crystal structures of photosystem I and II indicating the involvement of glycerolipids in photosynthesis8,11. During phosphate starvation, DGDG is transferred to extraplastidic membranes to compensate the loss of phospholipids9,12. Much of our knowledge of the biosynthesis and function of these lipids has been derived from a combination of genetic and biochemical studies with Arabidopsis thaliana14. During these studies, a simple procedure for the analysis of polar lipids has been essential for the screening and analysis of lipid mutants and will be outlined in detail. A leaf lipid extract is first separated by thin layer chromatography (TLC) and glycerolipids are stained reversibly with iodine vapor. The individual lipids are scraped from the TLC plate and converted to fatty acyl methylesters (FAMEs), which are analyzed by gas-liquid chromatography coupled with flame ionization detection (FID-GLC) (Figure 1). This method has been proven to be a reliable tool for mutant screening. For example, the tgd1,2,3,4 endoplasmic reticulum-to-plastid lipid trafficking mutants were discovered based on the accumulation of an abnormal galactoglycerolipid: trigalactosyldiacylglycerol (TGDG) and a decrease in the relative amount of 18:3 (carbons

  10. Layered inorganic-organic hybrid with talc-like structure for cation removal at the solid/liquid interface

    Energy Technology Data Exchange (ETDEWEB)

    Badshah, Syed [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP (Brazil); Airoldi, Claudio, E-mail: airoldi@iqm.unicamp.br [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP (Brazil)

    2013-01-20

    Graphical abstract: A lamellar inorganic-organic hybrid with talc-like structure has been synthesized through a single sol-gel step. Highlights: Black-Right-Pointing-Pointer New silylating agent isolated from acrylamide includes basic centers attached to enlarged chain. Black-Right-Pointing-Pointer Lamellar inorganic-organic talc-like structure has been synthesized through a single sol-gel step. Black-Right-Pointing-Pointer High basal distance accommodates the pendant chain in the cavities only in inclined disposition. Black-Right-Pointing-Pointer The pendant chain sorbs spontaneously and favorable cations as demonstrated by thermodynamic data. - Abstract: A new silylating agent N-((3-(3-(trimethoxysilyl)propylthio)propanamido)methyl)acrylamide synthesized from the reaction of N,N-methylenebisacrylamide and 3-mercaptopropyltrimethoxysilane yielded layered inorganic-organic talc-like magnesium phyllosilicate through the sol-gel process. Elemental analysis data based on sulfur demonstrated incorporation of 2.70 mmol g{sup -1} of organic moiety inside the lamellar cavities and the X-ray diffraction patterns confirmed the talc-like structure with a basal distance of 2.11 nm. Infrared spectroscopy, {sup 13}C and {sup 29}Si NMR in the solid state are in agreement with the presence of organic chains covalently bonded to the inorganic lamellar framework, as also supported by the presence of T{sup n} silicon species. Nitrogen, oxygen and sulfur basic centers sorb divalent lead, copper and cobalt cations with maximum capacity of 5.30, 3.82 and 1.60 mmol g{sup -1}. The thermodynamic data for cation/basic center interactions at the solid/liquid interface were determined through calorimetric titration with exothermic enthalpy, negative Gibbs energy and positive entropy, as expected for spontaneous and favorable reaction conditions.

  11. Low-temperature liquid-phase epitaxy and optical waveguiding of rare-earth-ion-doped KY(WO4)2 thin layers

    NARCIS (Netherlands)

    Romanyuk, Y.E.; Utke, I.; Ehrentraut, D.; Apostolopoulos, V.; Pollnau, Markus; Garcia-Revilla, S.; Valiente, B.

    2004-01-01

    Crystalline $KY(WO_{4})_{2}$ thin layers doped with different rare-earth ions were grown on b-oriented, undoped $KY(WO_{4})_{2}$ substrates by liquid-phase epitaxy employing a low-temperature flux. The ternary chloride mixture of NaCl, KCl, and CsCl with a melting point of 480°C was used as a solven

  12. Low-temperature liquid-phase epitaxy and optical waveguiding of rare-earth-ion-doped $KY(WO_{4})_{2}$ thin layers

    NARCIS (Netherlands)

    Romanyuk, Y.E.; Utke, I.; Ehrentraut, D.; Apostolopoulos, V.; Pollnau, M.; Garcia-Revilla, S.; Valiente, B.

    2004-01-01

    Crystalline $KY(WO_{4})_{2}$ thin layers doped with different rare-earth ions were grown on b-oriented, undoped $KY(WO_{4})_{2}$ substrates by liquid-phase epitaxy employing a low-temperature flux. The ternary chloride mixture of NaCl, KCl, and CsCl with a melting point of 480°C was used as a solven

  13. Numerical study and control method of interaction of nucleation and boundary layer separation in condensing flow

    Institute of Scientific and Technical Information of China (English)

    Liansuo AN; Zhi WANG; Zhonghe HAN

    2009-01-01

    The spontaneous nucleation flow in turbine cascade was numerically studied. The model was imple-mented within a full Navier-Stokes viscous flow solution procedure and the process of condensation was calculated by the quadrature method of moments that shows good accuracy with very broad size distributions.Results were presented for viscous and inviscous flow,showing the influence of boundary layer separation and wake vortices on spontaneous nucleation. The results show that the degree of flow separation in wet steam flow is greater than that in superheated steam flow due to condensation shock and that the loss cannot be neglected.Furthermore, the impact of boundary layer separation and wake vortices on velocity profiles and its implications for profile loss were considered. The calculations showed that layer separation and wake vortices influence nucleation rate, leading to different droplet distributions. A method for controlling homogeneous nucleation and for reducing degree of flow separation in high-speed transonic wet steam flow was presented. The liquid phase parameter distribution is sensitive to the suction side profile of turbine cascade, which impacts the nucleation rate distribution leading to different droplet distributions and affects the degree of flow separation. The numerical study provides a practical design method for turbine blade to reduce wetness losses.

  14. Influence of element Cu on hydrogen content in superheated aluminum melt

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrogen content in molten Al-Cu alloy increases remarkably when the temperature of the melt rises to about 780  ℃. The effects of alloying element are theoretically analyzed in terms of Wagner interaction parameter. Furthermore, analyses indicate that the alloy element Cu plays an important role in the hydrogen content in superheated Al-Cu alloy melt below about 780  ℃. The conclusion is drawn that the degree of gassing in molten Al-Cu alloy is bound up with the properties of oxide film of Al alloy melts. The results make it clear that the hydrogen content in the molten aluminum reduces with increasing element Cu dissolved in aluminum melts at the same temperature.

  15. A neutron spectrometer based on temperature variations in superheated drop compositions

    CERN Document Server

    Apfel, R E

    2002-01-01

    The response of superheated drop detectors (SDDs) to neutron radiation varies in a self-consistent manner with variations in temperature and pressure, making such compositions suitable for neutron spectrometry. The advantage of this approach is that the response functions of candidate materials versus energy as the temperature or pressure is varied are nested and have distinct thresholds, with no thermal neutron response. These characteristics permit unfolding without the uncertainties associated with other spectrometry techniques, where multiple solutions are possible, thus requiring an initial guess of the spectrum. A spectrometer was developed based on the well-established technology for acoustic sensing of bubble events interfaced with a proportional-integral-derivative temperature controller. The active monitor for neutrons, called REMbrandt sup T sup M , was used as the platform for controlling temperature on a SDD probe and for data acquisition, thereby automating the process of measuring the neutron e...

  16. Effect of Melt Superheating Treatment on the Latent Heat Release of Sn

    Science.gov (United States)

    Xu, Junfeng; Dang, Bo; Fan, Dandan; Jian, Zengyun

    2017-03-01

    The accuracy of the baseline evaluation is of importance for calculating the transition enthalpy such as the latent heat of the crystallization. This study demonstrates the modified method of the equivalent non-latent heat baseline, by which the transition enthalpy can be measured accurately according to the transition peak in differential scanning calorimetric curve. With this method, the effect of melt superheating treatment time on the latent heat release upon the solidification of tin is investigated. The results show that the latent heat increases by increasing the treatment time, and is close to a constant when the treatment time is large enough, indicating the homogeneous system. And then, a simple model is established to describe the changes of the crystallization latent heat with the treatment time, which is confirmed by the experimental data of Sn.

  17. Superheated-drop (bubble) neutron detectors and their compliance with ICRP-60

    Energy Technology Data Exchange (ETDEWEB)

    d' Errico, F. (Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari Istituto Nazionale di Fisica Nucleare, Pisa (Italy)); Alberts, W.G. (Physikalisch-Technische Bundesanstalt, Braunschweig (Germany))

    1994-01-01

    Several devices based on superheated-drop detector technology have become available almost simultaneously with the release of new ICRP and ICRU publications. Given this circumstance, a study of the characteristics of the system has been undertaken by the authors considering the revised recommendations for neutron dosimetry. The dose equivalent response in free air has been examined experimentally as a function of energy from thermal up to 70 MeV neutrons, and its dependence on the angle of incidence has been tested on a phantom at 0.57 MeV. Some results are discussed with respect to lower limit of detection, temperature sensitivity, [gamma] discrimination, batch-to-batch uniformity, and reproducibility. Some conclusions in terms of advantages, limitations and possible applications of the system are presented. (author).

  18. Antifreeze protein-induced superheating of ice inside Antarctic notothenioid fishes inhibits melting during summer warming.

    Science.gov (United States)

    Cziko, Paul A; DeVries, Arthur L; Evans, Clive W; Cheng, Chi-Hing Christina

    2014-10-07

    Antifreeze proteins (AFPs) of polar marine teleost fishes are widely recognized as an evolutionary innovation of vast adaptive value in that, by adsorbing to and inhibiting the growth of internalized environmental ice crystals, they prevent death by inoculative freezing. Paradoxically, systemic accumulation of AFP-stabilized ice could also be lethal. Whether or how fishes eliminate internal ice is unknown. To investigate if ice inside high-latitude Antarctic notothenioid fishes could melt seasonally, we measured its melting point and obtained a decadal temperature record from a shallow benthic fish habitat in McMurdo Sound, Antarctica. We found that AFP-stabilized ice resists melting at temperatures above the expected equilibrium freezing/melting point (eqFMP), both in vitro and in vivo. Superheated ice was directly observed in notothenioid serum samples and in solutions of purified AFPs, and ice was found to persist inside live fishes at temperatures more than 1 °C above their eqFMP for at least 24 h, and at a lower temperature for at least several days. Field experiments confirmed that superheated ice occurs naturally inside wild fishes. Over the long-term record (1999-2012), seawater temperature surpassed the fish eqFMP in most summers, but never exceeded the highest temperature at which ice persisted inside experimental fishes. Thus, because of the effects of AFP-induced melting inhibition, summer warming may not reliably eliminate internal ice. Our results expose a potentially antagonistic pleiotropic effect of AFPs: beneficial freezing avoidance is accompanied by melting inhibition that may contribute to lifelong accumulation of detrimental internal ice crystals.

  19. Solid-liquid work of adhesion of coarse-grained models of n-hexane on graphene layers derived from the conditional reversible work method.

    Science.gov (United States)

    Ardham, Vikram Reddy; Deichmann, Gregor; van der Vegt, Nico F A; Leroy, Frédéric

    2015-12-28

    We address the question of how reducing the number of degrees of freedom modifies the interfacial thermodynamic properties of heterogeneous solid-liquid systems. We consider the example of n-hexane interacting with multi-layer graphene which we model both with fully atomistic and coarse-grained (CG) models. The CG models are obtained by means of the conditional reversible work (CRW) method. The interfacial thermodynamics of these models is characterized by the solid-liquid work of adhesion WSL calculated by means of the dry-surface methodology through molecular dynamics simulations. We find that the CRW potentials lead to values of WSL that are larger than the atomistic ones. Clear understanding of the relationship between the structure of n-hexane in the vicinity of the surface and WSL is elucidated through a detailed study of the energy and entropy components of WSL. We highlight the crucial role played by the solid-liquid energy fluctuations. Our approach suggests that CG potentials should be designed in such a way that they preserve the range of solid-liquid interaction energies, but also their fluctuations in order to preserve the reference atomistic value of WSL. Our study thus opens perspectives into deriving CG interaction potentials that preserve the thermodynamics of solid-liquid contacts and will find application in studies that intend to address materials driven by interfaces.

  20. Solid-liquid work of adhesion of coarse-grained models of n-hexane on graphene layers derived from the conditional reversible work method

    Energy Technology Data Exchange (ETDEWEB)

    Ardham, Vikram Reddy; Leroy, Frédéric, E-mail: vandervegt@csi.tu-darmstadt.de, E-mail: f.leroy@theo.chemie.tu-darmstadt.de [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt (Germany); Deichmann, Gregor; Vegt, Nico F. A. van der, E-mail: vandervegt@csi.tu-darmstadt.de, E-mail: f.leroy@theo.chemie.tu-darmstadt.de [Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt (Germany)

    2015-12-28

    We address the question of how reducing the number of degrees of freedom modifies the interfacial thermodynamic properties of heterogeneous solid-liquid systems. We consider the example of n-hexane interacting with multi-layer graphene which we model both with fully atomistic and coarse-grained (CG) models. The CG models are obtained by means of the conditional reversible work (CRW) method. The interfacial thermodynamics of these models is characterized by the solid-liquid work of adhesion W{sub SL} calculated by means of the dry-surface methodology through molecular dynamics simulations. We find that the CRW potentials lead to values of W{sub SL} that are larger than the atomistic ones. Clear understanding of the relationship between the structure of n-hexane in the vicinity of the surface and W{sub SL} is elucidated through a detailed study of the energy and entropy components of W{sub SL}. We highlight the crucial role played by the solid-liquid energy fluctuations. Our approach suggests that CG potentials should be designed in such a way that they preserve the range of solid-liquid interaction energies, but also their fluctuations in order to preserve the reference atomistic value of W{sub SL}. Our study thus opens perspectives into deriving CG interaction potentials that preserve the thermodynamics of solid-liquid contacts and will find application in studies that intend to address materials driven by interfaces.

  1. Combustion of liquid fuels floating on water

    Directory of Open Access Journals (Sweden)

    Garo Jean-Pierre

    2007-01-01

    Full Text Available The research presented consists of a study of the burning characteristics of a liquid fuel floating on water with emphasis in the phenomena known as boilover. The problem is of technical interest in the petro-chemical industry, particularly from the point of view of pollution and fires resulting from accidental liquid fuel spills in open water. Testing with multicomponent fuels gives information's about events that can occur in a practical situation, while testing with single component fuels permits obtaining fundamental information about the problem. It evidences the major effects caused by the transfer of heat from the fuel to the water underneath. One of these effects is the disruptive burning of the fuel known as boilover, that is caused by the water boiling and splashing, and results in a sharp increase in burning rate and often in the explosive burning of the fuel. It is shown that this event is caused by the onset of water boiling nucleation at the fuel/water interface and that it occurs at an approximate constant temperature that is above the saturation temperature of the water (water is superheated. These measurements conducted in two laboratories, address the major issues of the process by analyzing the effect of the variation of the parameters of the problem (initial fuel-layer thickness, pool diameter, and fuel type, on the burning rate, time to start of boilover, pre-boilover mass ratio, and boilover intensity. Finally, two types of modeling are proposed to describe the heat transfer in fuel and water phases: one simple for practical purposes, the other, more elaborated and transient, taking particularly into consideration the radiation in depth.

  2. One-step synthesis of layered yttrium hydroxides in immiscible liquid–liquid systems: Intercalation of sterically-bulky hydrophobic organic anions and doping of europium ions

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Mebae; Fujihara, Shinobu, E-mail: shinobu@applc.keio.ac.jp

    2014-02-15

    Inorganic–organic layered rare-earth compounds were synthesized on the basis of a biphasic liquid–liquid system in one pot. Layered yttrium hydroxides (LYHs) were chosen as a host material for the intercalation of hydrophobic organic guest anions such as benzoate, sebacate, or laurate. In a typical synthesis, an organic phase dissolving carboxylic acid was placed in contact with an equal amount of an aqueous phase dissolving yttrium nitrate n-hydrate and urea. At elevated temperatures up to 80 °C, urea was hydrolyzed to release hydroxyl anions which were used to form yttrium hydroxide layers. LYHs were then precipitated with the intercalation of carboxylate anions delivered from the organic phase under the distribution law. The structure and the morphology of the LYHs could be modulated by the intercalated anions. Doped with Eu{sup 3+} ions, the LYHs exhibited red photoluminescence which was enhanced by the intercalated anions due to the antenna effect. - Graphical abstract: The Eu{sup 3+}-doped layered yttrium hydroxide exhibits intense red photoluminescence after intercalation of benzoate ions. Display Omitted - Highlights: • Immiscible biphasic liquid systems were introduced to synthesize layered yttrium hydroxides. • The temperature of the biphasic systems does not exceed 80 °C in one step of the synthesis. • Hydrophobic organic anions were intercalated between the hydroxide layers in one pot. • Structure and morphology of the hydroxides were modulated by changing the kind of organic anions. • Eu{sup 3+}-doping led to red luminescence from the hydroxides in association with the intercalated organic anions.

  3. Development of an HPLC method to analyze and prepare elsinochrome C and hypocrellin A in the submerged fermentation broth of Shiria sp. SUPER-H168.

    Science.gov (United States)

    Hu, Mingming; Cai, Yujie; Liao, Xiangru; Hao, Zhikui; Liu, Jiayang

    2012-06-01

    A rapid and sensitive analytical method based on reverse-phase high-performance liquid chromatography was first developed to simultaneously determine elsinochrome C (EC) and hypocrellin A (HA) in the submerged fermentation. The mobile phase consisted of acetonitrile-water 60:40 (v/v) with a flow-rate of 1 mL/min. The calibration curves were as follows: y = 37,625x + 249,775 for EC, y = 30,813x + 556,409 for HA and linear at the investigated concentration. The correlation coefficients (R(2) ) were 0.9989 and 0.9998 respectively for EC and HA. The limits of detection and quantification were 175 and 585 µg/L for EC and 205 and 610 µg/L for HA. The precisions of concentration and retention times were less than 2.5 and 0.3%. The recovery of the method was greater than 95.0%. The methodology was applied to analyze simultaneously EC and HA concentrations in a submerged fermentation, and was adequate for analysis of biosynthesis of perylenequinones. The method was also amplified to separate and purify EC and HA using a semi-preparative C(18) column. In addition, elsinochrome C was first identified in the submerged fermentation broth of Shiraia sp. SUPER-H168. Copyright © 2011 John Wiley & Sons, Ltd.

  4. Non-Intrusive, Real-Time, On-Line Temperature Sensor for Superheated Hydrogen at High Pressure and High Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The SSC needs a hydrogen temperature sensor that can provide high accuracy, fast response and can be operated on a superheated hydrogen (SHH2) environment. This will...

  5. Modeling of Uneven Flow and Electromagnetic Field Parameters in the Combustion Chamber of Liquid Rocket Engine with a Near-wall Layer Available

    Directory of Open Access Journals (Sweden)

    A. V. Rudinskii

    2015-01-01

    Full Text Available The paper concerns modeling of an uneven flow and electromagnetic field parameters in the combustion chamber of the liquid rocket engine with a near-wall layer available.The research objective was to evaluate quantitatively influence of changing model chamber mode of the liquid rocket engine on the electro-physical characteristics of the hydrocarbon fuel combustion by-products.The main method of research was based on development of a final element model of the flowing path of the rocket engine chamber and its adaptation to the boundary conditions.The paper presents a developed two-dimensional non-stationary mathematical model of electro-physical processes in the liquid rocket engine chamber using hydrocarbon fuel. The model takes into consideration the features of a gas-dynamic contour of the engine chamber and property of thermo-gas-dynamic characteristics of the ionized products of combustion of hydrocarbonic fuel. Distributions of magnetic field intensity and electric conductivity received and analyzed taking into account a low-temperature near-wall layer. Special attention is paid to comparison of obtained calculation values of the electric current, which is taken out from intrachamber space of the engine with earlier published data of other authors.

  6. Surface segregation as a means of gettering Cu in liquid-phase-epitaxy silicon thin layers grown from Al-Cu-Si solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.H.; Ciszek, T.F.; Reedy, R.; Asher, S.; King, D. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    The authors demonstrate that, by using the natural surface segregation phenomenon, Cu can be gettered to the surface from the bulk of silicon layers so that its concentrations in the liquid-phase-epitaxy (LPE) layers are much lower than its solubility at the layer growth temperature and the reported 10{sup 17} cm{sup {minus}3} degradation threshold for solar-cell performance. Secondary-ion mass spectroscopy (SIMS) analysis indicates that, within a micron-deep sub-surface region, Cu accumulates even in as-grown LPE samples. Slower cooling after growth to room temperature enhances this Cu enrichment. X-ray photoelectron spectroscopy (XPS) measurement shows as much as 3.2% Cu in a surface region of about 50 {Angstrom}. More surface-sensitive, ion-scattering spectroscopy (ISS) analysis further reveals about 7% of Cu at the top surface. These results translate to an areal gettering capacity of about 1.0 x 10{sup 16} cm{sup {minus}2}, which is higher than the available total-area density of Cu in the layer and substrate (3.6 x 10{sup 15} cm{sup {minus}2} for a uniform 1.2 x 10{sup 17}cm{sup {minus}3} Cu throughout the layer and substrate with a total thickness of 300 {mu}m).

  7. Effects of aggregates on mixed adsorption layers of poly(ethylene imine) and sodium dodecyl sulfate at the air/liquid interface.

    Science.gov (United States)

    Tonigold, Katrin; Varga, Imre; Nylander, Tommy; Campbell, Richard A

    2009-04-07

    We have exploited the spatial and kinetic resolution of ellipsometry to monitor the lateral movement of inhomogeneous patches of material in mixed adsorption layers of poly(ethylene imine) and sodium dodecyl sulfate at the air/liquid interface. We show that the choice of sample preparation methods can have a profound effect on the state of the interface for chemically equivalent samples. The extent of aggregation in the bulk solution on relevant time scales is affected by specific details of the polymer/surfactant mixing process, which produces varying numbers of aggregates that can become trapped in the interfacial layer, resulting in an enhanced and fluctuating ellipsometry signal. It can be beneficial to apply the surface-cleaning method of aspiration prior to physical measurements to remove trapped aggregates through the creation of a fresh interface. At low pH, the ellipsometry signal of samples prepared with surface cleaning is remarkably constant over a factor of >500 in the bulk composition below charge equivalence, which is discussed in terms of possible adsorption mechanisms. At high pH, through observing temporal fluctuations in the ellipsometry signal of samples prepared with surface cleaning, we reveal two important processes: there is the spontaneous adsorption of aggregates > 0.2 microm in diameter into the interfacial layer, and with time there is the fusion of smaller aggregates to generate new large surface aggregates. We attribute the favorability of the adsorption and fusion processes at high pH to reduced electrostatic barriers resulting from the low surface charge density of the aggregates. It is inappropriate in this case to consider the interface to comprise a homogeneous adsorption layer that is in dynamic equilibrium with the bulk solution. Our work shows that it can be helpful to consider whether there are macroscopic particles embedded in molecular layers at the air/liquid interface for systems where there is prior knowledge of

  8. A novel technique for response function determination of shear sensitive cholesteric liquid crystals for boundary layer investigations

    Science.gov (United States)

    Parmar, D. S.

    1991-01-01

    A description of the design and setup of an experimental technique for measurement of the response function in shear sensitive liquid crystals has been reported. Utilizing the selective reflection characteristics of cholesteric liquid crystals, the method is capable of measuring the delay, rise, and relaxation times in response to a given dynamic shear stress as a function of the wavelength of the incident light. Application of a step input shear stress results in a liquid crystal time response that can be described as consisting of an initial delay, a shear induced helix deformation, and a relaxation to the initial state through diffusion processes. The method has been used for quantitative calibration of a shear sensitive liquid crystal by observing the peak in reflected light intensity, at a given wavelength, as a function of the shear stress.

  9. A Study on Solute Dispersion in a Three Layer Blood-like Liquid Flowing through a Rigid Artery

    National Research Council Canada - National Science Library

    Sudip Debnath; Apu Kumar Saha; Ashis Kumar Roy

    2017-01-01

    The unsteady dispersion of a solute has been discussed by the method of generalized dispersion technique in a blood-like liquid flowing through a pipe under the combined effects of finite yield stress...

  10. Mechanoresponsive change in photoluminescent color of rod-like liquid-crystalline compounds and control of molecular orientation on photoaligned layer

    Science.gov (United States)

    Kondo, Mizuho; Miura, Seiya; Okumoto, Kentaro; Hashimoto, Mayuko; Fukae, Ryohei; Kawatsuki, Nobuhiro

    2014-10-01

    In this paper, we reported novel liquid-crystalline luminophore that switches its photoluminescent color by mechanically grinding. Mechanochromic luminescence (MCL) is expected for mechanical sensor, cellular imaging, detection of microenvironmental changes, and optical memory. In this work, we focused on liquid-crystalline MCL compounds on alignment layer. Controlling the molecular alignment of MCL compounds with photoalignment layer have potential to succeed in functional MCL film such as polarized micropatterned MCL and directional detection of mechanical stimuli. Herein, we prepared asymmetric rodlike MCL compounds containing cyano- and pyridyl molecular terminal and explored their photoluminescence behavior under mechanical stimulus. The cyano terminated compound showed a nematic phase and tuned its photoluminescent color from green to yellow upon grinding, while the pyridyl-terminated compounds that show no mesophase changed its photoluminescent color from blue to green and reverted to its initial color by heating above its melting point. The cyano-terminated MCL was aligned along the orientation direction of photoalignment layer and pyridyl-terminated MCL exhibited uniaxial alignment when it coated on photoaligned film containing carboxylic acid.

  11. Thermal Hydraulic Design and Analysis of a Water-Cooled Ceramic Breeder Blanket with Superheated Steam for CFETR

    Science.gov (United States)

    Cheng, Xiaoman; Ma, Xuebin; Jiang, Kecheng; Chen, Lei; Huang, Kai; Liu, Songlin

    2015-09-01

    The water-cooled ceramic breeder blanket (WCCB) is one of the blanket candidates for China fusion engineering test reactor (CFETR). In order to improve power generation efficiency and tritium breeding ratio, WCCB with superheated steam is under development. The thermal-hydraulic design is the key to achieve the purpose of safe heat removal and efficient power generation under normal and partial loading operation conditions. In this paper, the coolant flow scheme was designed and one self-developed analytical program was developed, based on a theoretical heat transfer model and empirical correlations. Employing this program, the design and analysis of related thermal-hydraulic parameters were performed under different fusion power conditions. The results indicated that the superheated steam water-cooled blanket is feasible. supported by the National Special Project for Magnetic Confined Nuclear Fusion Energy of China (Nos. 2013GB108004, 2014GB122000 and 2014GB119000), and National Natural Science Foundation of China (No. 11175207)

  12. A Theoretical Study of Love Wave Sensors Based on ZnO–Glass Layered Structures for Application to Liquid Environments

    OpenAIRE

    2016-01-01

    The propagation of surface acoustic Love modes along ZnO/glass-based structures was modeled and analysed with the goal of designing a sensor able to detect changes in the environmental parameters, such as liquid viscosity changes and minute amounts of mass supported in the viscous liquid medium. Love mode propagation was modeled by numerically solving the system of coupled electro-mechanical field equations and Navier–Stokes equations. The phase and group velocities and the attenuation of the...

  13. Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

    Directory of Open Access Journals (Sweden)

    Dietmar Gerteisen

    2013-09-01

    Full Text Available In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

  14. Selective hydrogenation of 1,3-butadiene from crude C{sub 4} cracker stream with a solid catalyst with ionic liquid layer (SCILL). DSC and solubility study

    Energy Technology Data Exchange (ETDEWEB)

    Mangartz, T.; Korth, W.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2013-11-01

    In petroleum as well as in fine chemical industry, selective catalytic hydrogenation is an important reaction. The selective hydrogenation of 1,3-butadiene (BD) to butene (trans-,1- and cis-butene) from the crude C4 steam cracker fraction represents one example, but under today's technical conditions undesired butane forms inevitably in relevant amounts. To increase the butene yield, the concept of Solid Catalyst with Ionic Liquid Layer (SCILL) was employed. The SCILL catalyst, in contrast to the uncoated catalyst, yielded a remarkably high selectivity to butenes (S{sub butenes} > 99 %) even at high residence times or at high hydrogen partial pressure. Nearly no butane (S{sub butane} {approx} 0 %) was analytically detected. We expected that due to different solubility, the poorer soluble compounds discharged from the ionic liquid and, thus, caused the shift in selectivity to a great extent. Temperature dependent solubility measurements in the used ionic liquid ([DMIM][DMP]) revealed that the order of increasing solubility is 1,3-butadiene > butenes > butane which matches the assumption. However, since differences in solubility cannot explain this SCILL effect satisfyingly, ionic liquids are expected to affect the surface of the catalyst (side-specific ligand-type effect). Investigations using spectroscopic methods (e.g. FTIR) confirmed this suggestion. (orig.)

  15. Layering and shear properties of an ionic liquid, 1-ethyl-3-methylimidazolium ethylsulfate, confined to nano-films between mica surfaces.

    Science.gov (United States)

    Perkin, Susan; Albrecht, Tim; Klein, Jacob

    2010-02-14

    We report high-resolution measurements of the forces between two atomically smooth solid surfaces across a film of 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid, for film thickness down to a single ion diameter. For films thinner than approximately 2 nm oscillatory structural forces are observed as the surface separation decreases and pairs of ion layers are squeezed out of the film. Strikingly, measurements of the shear stress of the ionic liquid film reveal low friction coefficients which are 1-2 orders of magnitude smaller than for analogous films of non-polar molecular liquids, including standard hydrocarbon lubricants, up to ca. 1 MPa pressure. We attribute this to the geometric and charge characteristics of the ionic liquid: the irregular shapes of the ions lead to a low shear stress, while the strong coulombic interactions between the ions and the charged confining surfaces lead to a robust film which is maintained between the shearing surfaces when pressure is applied across the film.

  16. Evaluation of the thermal effect on separation selectivity in anion-exchange processes using superheated water ion-exchange chromatography.

    Science.gov (United States)

    Shibukawa, Masami; Taguchi, Akihiko; Suzuki, Yusuke; Saitoh, Kazunori; Hiaki, Toshihiko; Yarita, Takashi

    2012-07-07

    The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 °C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature.

  17. Emission estimation of neat paradise tree oil combustion assisted with superheated hydrogen in a 4-stroke natural aspirated DICI engine

    Directory of Open Access Journals (Sweden)

    Sundararajan Karthikayan

    2016-01-01

    Full Text Available This research work investigates the use of neat paradise tree oil in a 4-stroke natural aspirated direct injection compression ignition engine assisted with the help of super-heated hydrogen (hydrogen in gaseous state or above its saturation temperature as a combustion improver. The high calorific gaseous fuel hydrogen gas was used as a combustion improver and admitted into the engine during the suction stroke. A 4-stroke single cylinder Diesel engine was chosen and its operating parameters were suitably modified. Neat paradise tree oil was admitted through standard injector of the engine and hydrogen was admitted through induction manifold. Inducted super-heated hydrogen was initiated the intermediate compounds combustion of neat paradise tree oil. This process offers higher temperature combustion and results in complete combustion of heavier molecules of neat paradise tree oil within shorter duration. The results of the experiment reveal that 40% higher NOx, 20% lower smoke, 5% lower CO, and 45% lower HC than that of neat paradise tree oil fuel operation and the admission of superheated hydrogen has improved the combustion characteristics of neat paradise tree oil. The investigation successfully proved that the application of neat paradise tree oil with 15% of hydrogen improver is possible under a regular Diesel engine with minimal engine modification.

  18. Role of superheated water in the origin of life; Seimei no kigen ni hatashita nessui no yakuwari

    Energy Technology Data Exchange (ETDEWEB)

    Yanagawa, H. [Mitsubishi Kasei Corp., Tokyo (Japan)

    1994-09-01

    High-temperature hot water environments at the bottom of seas are drawing attentions recently. This paper describes the consideration on actions of superheated water that contribute to the origin of life. Gushing of superheated water from cracks in ocean bottoms is discovered in the eastern Pacific oceanic rises, Okinawa and other parts of the world. Jet holes are characterized by having higher concentration in such a reducing gas as methane (CH4), and being more reducing than the surrounding sea water. Concentrations of ions of metals such as Fe is 1000 times or more higher than that in the sea water, which is advantageous for organics composing reaction in the superheated water. An investigation has been carried out on organics synthesis under the environment where ocean bottom hot water jet holes exist. Sea waters were manufactured on an experimental basis by using a hot water jetting hole model. As a result of various discussions, proteins such as glycine, amino acid, and non-protein {beta}-alanine were produced. With respect to the evolution of chemical actions, high-pressure heating of mixed solution containing glycine has generated microsphere. Temperature dependence of peptide generation was also made clear. Regarding the hydrogen fugacity at the actual jetting holes, the stability of amino acid is remarkably increased when 1% H2 is added into the pressurizing N2. 6 refs., 2 figs.

  19. Superheated water ion-exchange chromatography: an experimental approach for interpretation of separation selectivity in ion-exchange processes.

    Science.gov (United States)

    Shibukawa, Masami; Shimasaki, Tomomi; Saito, Shingo; Yarita, Takashi

    2009-10-01

    Cation-exchange selectivity for alkali and alkaline-earth metal ions and tetraalkylammonium ions on a strongly acidic sulfonic acid cation-exchange resin has been investigated in the temperature range of 40-175 degrees C using superheated water chromatography. Dependence of the distribution coefficient (ln KD) on the reciprocal of temperature (1/T) is not linear for most of the ions studied, and the selectivity coefficient for a pair of alkali metal ions or that of alkaline-earth metal ions approaches unity as temperature increases. On the other hand, the retention order of tetraalkylammonium ions is reversed at 160 degrees C or above when eluted with Na2SO4 aqueous solution and the larger ions are eluted faster than the smaller ones contrary to the retention order obtained at ambient temperature. The change in ion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions and specific adsorption or distribution of ionic species between the external solution and ion-exchange resin. In superheated water, the electrostatic interaction or association of the ions with the fixed ion becomes a predominant mechanism resulting in different separation selectivity from that obtained at ambient temperature.

  20. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

  1. Experiments on the multi-roll-structure of thermocapillary flow in side-heated thin liquid layers

    Science.gov (United States)

    Schwabe, D.; Cramer, A.; Schneider, J.; Benz, S.; Metzger, J.

    1999-01-01

    The multi-roll-structure (MRS) with convection rolls, all with the same sense of rotation and axes perpendicular to the applied temperature gradient appears in thin layers driven by thermocapillarity prior to time dependent states. Detailed experimental and numerical results are reported. The MRS in large Prandtl-number fluids is dominated by thermocapillarity and separates from the buoyancy driven bulk flow for deep layers. We prepare a microgravity experiment MAGIA to study thermocapillary flow structures without coupling to buoyancy in a 20.0 mm wide annular layer with free surface of variable depth heated by the outer wall and cooled at the inside.

  2. Electrically induced circular dichroism of multi-domain layers of a long-pitch cholesteric liquid crystal

    Science.gov (United States)

    Yakovlev, Dmitry D.; Sherman, Maria M.; Yakovlev, Dmitry A.

    2014-01-01

    Circular dichroism is typical of cholesteric materials with a cholesteric pitch of the order of light wavelength, where it is connected with selective reflection of one of the circularly polarized components of light. In this work we report, for the first time, on our observations of circular dichroism on multi-domain layers of a nonabsorbing cholesteric LC material whose natural cholesteric pitch is much larger than the wavelength of incident light. It is demonstrated that the degree of manifestation of the circular dichroism depends heavily on the LC layer thickness, voltage applied to the layer, and wavelength.

  3. Mass conservational equations at the solid-liquid interface and self-organization model of some growth layers

    Institute of Scientific and Technical Information of China (English)

    吴金平; 李才伟; 肖文丁; 杨问华

    1997-01-01

    Equations of interface mass conservation of nonsteady-state crystalline growth process are established. These equations provide a basic mathematical model for the strict treatment of the non-equilibrium and nonlinear problems in the formation of crystalline growth layers. A kinetic model is built of nonlinear self-catalytic crystalline reaction for the formation of impurity growth layer in flux single crystalline growth. Discussion is made, from the formation of self-organization pattern, on some origins of growth layers that are difficult to explain by existing theories

  4. Analysis of Liquid–Liquid Droplets Fission and Encapsulation in Single/Two Layer Microfluidic Devices Fabricated by Xurographic Method

    Directory of Open Access Journals (Sweden)

    Chang Nong Lim

    2017-02-01

    Full Text Available This paper demonstrates a low cost fabrication approach for microscale droplet fission and encapsulation. Using a modified xurography method, rapid yet reliable microfluidic devices with flexible designs (single layer and double layer are developed to enable spatial control of droplet manipulation. In this paper, two different designs are demonstrated, i.e., droplet fission (single layer and droplet encapsulation (double layer. In addition, the current fabrication approach reduces the overall production interval with the introduction of a custom-made polydimethylsiloxane (PDMS aligner. Apart from that, the fabricated device is able to generate daughter droplets with the coefficient of variance (CV below 5% and double emulsions with CV maintained within 10% without involvement of complex surface wettability modification.

  5. In-cell Western™ detection of organic cation transporters in bronchial epithelial cell layers cultured at an air-liquid interface on Transwell(®) inserts.

    Science.gov (United States)

    Mukherjee, M; Latif, M L; Pritchard, D I; Bosquillon, C

    2013-01-01

    Organic cation transporters (OCT) have been shown to mediate the transport of inhaled drugs in bronchial epithelial cells and might have important physiological functions in the airway epithelium. However, a quantitative method to evaluate OCT protein expression in physiologically relevant airway epithelial cell culture models is currently lacking. In-cell Western™ (ICW) techniques might fill that gap but to date, have only been performed on cells grown on 96 or 384-well microplates. An ICW assay was designed for measuring levels of the different OCT subtypes in intact layers of the human bronchial epithelial Calu-3 cell line cultured at an air-liquid interface on Transwell(®) inserts. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as the internal standard for normalisation of cell number between the layers. The protocol was subsequently validated by exposing cell layers to compounds known to cause variations in OCT expression. Antibody signals above the background fluorescence were detected for OCT1, OCT3, OCTN1 and OCTN2 but not for OCT2 in 21day old Calu-3 layers, in agreement with previous studies which had reported OCT2 was absent in the Calu-3 cell line. Furthermore, increases in the fluorescence signal associated with OCT1, OCTN1 and OCTN2 were obtained following treatment of the layers with, respectively, the nitric oxide inducer sodium nitroprusside, the peroxisome proliferator activated receptor α (PPARα) agonist fenofibrate or the PPARγ agonist rosiglitazone, confirming the reliability of the ICW method developed. However, a suitable positive control for OCT3 could not be identified. This novel ICW assay can be exploited to quantify basal OCT protein expression as well as changes in transporter levels following external stimuli in various in vitro models. It can also be easily adapted to probe any protein in epithelial layers maintained on permeable filters. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Sequential microwave superheated water extraction of mannans from spent coffee grounds.

    Science.gov (United States)

    Passos, Cláudia P; Moreira, Ana S P; Domingues, M Rosário M; Evtuguin, Dmitry V; Coimbra, Manuel A

    2014-03-15

    The feasibility of using sequential microwave superheated water extraction (MAE) for the recovery of mannans from spent coffee grounds (SCG) was studied. Due to the high contents of mannose still present in the SCG residue left after two consecutive MAE, the unextracted material was re-suspended in water and submitted to a third microwave irradiation (MAE3) at 200 °C for 3 min. With MAE3, mannose recovery achieved 48%, increasing to 56% by MAE4, and reaching a maximum of 69% with MAE5. Glycosidic-linkage analysis showed that in MAE3 mainly galactomannans were recovered, while debranched galactomannans were recovered with MAE4 and MAE5. With increasing the number of extractions, the average degree of polymerization of the mannans decreased, as observed by size-exclusion chromatography and by methylation analysis. Scanning electron microscopy images showed a decrease on cell walls thickness. After final MAE5, the remaining un-extracted insoluble material, representing 22% of the initial SCG, was composed mainly by cellulose (84%).

  7. Modification of oil palm mesocarp fiber characteristics using superheated steam treatment.

    Science.gov (United States)

    Nordin, Noor Ida Amalina Ahamad; Ariffin, Hidayah; Andou, Yoshito; Hassan, Mohd Ali; Shirai, Yoshihito; Nishida, Haruo; Yunus, Wan Zin Wan; Karuppuchamy, Subbian; Ibrahim, Nor Azowa

    2013-07-30

    In this study, oil palm mesocarp fiber (OPMF) was treated with superheated steam (SHS) in order to modify its characteristics for biocomposite applications. Treatment was conducted at temperatures 190-230 °C for 1, 2 and 3 h. SHS-treated OPMF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. OPMF treated at 230 °C exhibited lower hemicellulose content (9%) compared to the untreated OPMF (33%). Improved thermal stability of OPMF was found after the SHS treatment. Moreover, SEM and ICP analyses of SHS-treated OPMF showed that silica bodies were removed from OPMF after the SHS treatment. XRD results exhibited that OPMF crystallinity increased after SHS treatment, indicating tougher fiber properties. Hemicellulose removal makes the fiber surface more hydrophobic, whereby silica removal increases the surface roughness of the fiber. Overall, the results obtained herewith suggested that SHS is an effective treatment method for surface modification and subsequently improving the characteristics of the natural fiber. Most importantly, the use of novel, eco-friendly SHS may contribute to the green and sustainable treatment for surface modification of natural fiber.

  8. A neutron spectrometer based on temperature variations in superheated drop compositions

    Energy Technology Data Exchange (ETDEWEB)

    Apfel, Robert E. E-mail: robert.apfel@yale.edu; D' Errico, Francesco

    2002-01-01

    The response of superheated drop detectors (SDDs) to neutron radiation varies in a self-consistent manner with variations in temperature and pressure, making such compositions suitable for neutron spectrometry. The advantage of this approach is that the response functions of candidate materials versus energy as the temperature or pressure is varied are nested and have distinct thresholds, with no thermal neutron response. These characteristics permit unfolding without the uncertainties associated with other spectrometry techniques, where multiple solutions are possible, thus requiring an initial guess of the spectrum. A spectrometer was developed based on the well-established technology for acoustic sensing of bubble events interfaced with a proportional-integral-derivative temperature controller. The active monitor for neutrons, called REMbrandt{sup TM}, was used as the platform for controlling temperature on a SDD probe and for data acquisition, thereby automating the process of measuring the neutron energy spectrum. The new instrument, called REM-SPEC{sup TM}, implements and automates the original BINS approach: it adjusts the temperature of the SDD vial in increasing steps and measures the bubble event rate at each step. By using two distinct SDD materials with overlapping responses, the 0.1-20 MeV range of energies relevant to practical spectrometry is readily covered. Initial experiments with an Am-Be source validate the operational protocols of this device.

  9. Kinetics of the reaction between H{sup ·} and superheated water probed with muonium

    Energy Technology Data Exchange (ETDEWEB)

    Alcorn, Chris D. [Department of Chemistry and Biochemistry, Mount Allison University, Sackville, New Brunswick E4L 1G8 (Canada); Brodovitch, Jean-Claude [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Percival, Paul W. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Smith, Marisa [Department of Chemistry and Biochemistry, Mount Allison University, Sackville, New Brunswick E4L 1G8 (Canada); Ghandi, Khashayar, E-mail: kghandi@mta.ca [Department of Chemistry and Biochemistry, Mount Allison University, Sackville, New Brunswick E4L 1G8 (Canada)

    2014-05-19

    Highlights: • Rate constants for reactions of H with water resolve a controversy. • H reacts with superheated water via two channels. • The findings have important implications for the safety of some nuclear power reactors. - Abstract: Safe operation of supercritical water-cooled reactors requires knowledge of the kinetics of transient species formed by the radiolysis of water in the range 300–650 °C. Using muonium, it is possible to study aqueous H{sup ·} atom chemistry over this temperature range. An important reaction to study is that of the H{sup ·} atom with water itself, because it is a potential source of molecular H{sub 2}. The concentration of H{sub 2} is important to plant coolant chemistry, as H{sub 2} is currently added to suppress oxidative corrosion in CANDU reactors. The reaction of muonium with H{sub 2}O and D{sub 2}O was studied experimentally up to 450 °C, and also via quantum chemical computations to investigate possible isotope effects. Our results suggest that although the H{sup ·} atom abstraction from H{sub 2}O is important at temperatures above 300 °C, the electron-producing channel (H{sup ·} + H{sub 2}O ⇌ H{sub 3}O{sup +} + e{sub aq}{sup -}) is significant at temperatures up to 300 °C, and becomes the dominant reaction channel at lower temperatures.

  10. Modification of Oil Palm Mesocarp Fiber Characteristics Using Superheated Steam Treatment

    Directory of Open Access Journals (Sweden)

    Subbian Karuppuchamy

    2013-07-01

    Full Text Available In this study, oil palm mesocarp fiber (OPMF was treated with superheated steam (SHS in order to modify its characteristics for biocomposite applications. Treatment was conducted at temperatures 190–230 °C for 1, 2 and 3 h. SHS-treated OPMF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. OPMF treated at 230 °C exhibited lower hemicellulose content (9% compared to the untreated OPMF (33%. Improved thermal stability of OPMF was found after the SHS treatment. Moreover, SEM and ICP analyses of SHS-treated OPMF showed that silica bodies were removed from OPMF after the SHS treatment. XRD results exhibited that OPMF crystallinity increased after SHS treatment, indicating tougher fiber properties. Hemicellulose removal makes the fiber surface more hydrophobic, whereby silica removal increases the surface roughness of the fiber. Overall, the results obtained herewith suggested that SHS is an effective treatment method for surface modification and subsequently improving the characteristics of the natural fiber. Most importantly, the use of novel, eco-friendly SHS may contribute to the green and sustainable treatment for surface modification of natural fiber.

  11. Monte Carlo evaluation of the neutron detection efficiency of a superheated drop detector

    Energy Technology Data Exchange (ETDEWEB)

    Gualdrini, G.F. [ENEA, Centro Ricerche `Ezio Clementel`, Bologna (Italy). Dipt. Ambiente; D`Errico, F.; Noccioni, P. [Pisa, Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari

    1997-03-01

    Neuron dosimetry has recently gained renewed attention, following concerns on the exposure of crew members on board aircraft, and of workers around the increasing number of high energy accelerators for medical and research purpose. At the same time the new operational qualities for radiation dosimetry introduced by ICRU and the ICRP, aiming at a unified metrological system applicable to all types of radiation exposure, involved the need to update current devices in order to meet new requirements. Superheated Drop (Bubble) Detectors (SDD) offer an alternative approach to neutron radiation protection dosimetry. The SDDs are currently studied within a large collaborative effort involving Yale University. New Haven CT, Pisa (IT) University, the Physikalisch-Technische Bundesanstalt, Braunschweig D, and ENEA (Italian National Agency for new Technologies Energy and the Environment) Centre of Bologna. The detectors were characterised through calibrations with monoenergetic neutron beams and where experimental investigations were inadequate or impossible, such as in the intermediate energy range , parametric Monte Carlo calculations of the response were carried out. This report describes the general characteristic of the SDDs along with the Monte Carlo computations of the energy response and a comparison with the experimental results.

  12. Monte Carlo evaluation of the neutron detection efficiency of a superheated drop detector

    Energy Technology Data Exchange (ETDEWEB)

    Gualdrini, G. F. [ENEA, Centro Ricerche `Ezio Clementel`, Bologna (Italy). Dipt. Ambiente; D`Errico, F.; Noccioni, P. [Pisa, Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari

    1997-06-01

    Neutron dosimetry has recently gained renewed attention, following concerns on the exposure of crew members on board aircraft, and of workers around the increasing number of high energy accelerators for medical and research purposes. At the same time the new operational quantities for radiation dosimetry introduced by ICRU and the ICRP, aiming at a unified metrological system applicable to all types of radiation exposure, involved the need to update current devices in order to meet new requirements. Superheated Drop (Bubble) Detectors (SDD) offer an alternative approach to neutron radiation protection dosimetry. The SDDs are currently studied within a large collaborative effort involving Yale University, New Haven CT, the `Universita` degli Studi di Pisa`, the Physikalisch-Technische Bundesanstalt, Braunschweig D. and ENEA (National Agency for New Technology, Energy and the Environment)-C.R., Bologna. The detectors were characterised through calibrations with monoenergetic neutron beams and where experimental investigations were inadequate or impossible, such as in the intermediate energy range, parametric Monte Carlo calculations of the response were carried out. This report describes the general characteristics of the SDDs along with the Monte Carlo computations of the energy response and a comparison with the experimental results.

  13. Kinetics of Texture and Colour Changes in Chicken Sausage during Superheated Steam Cooking

    Directory of Open Access Journals (Sweden)

    Abdulhameed Asmaa A.

    2016-07-01

    Full Text Available The aim of this study was to develop a kinetic model to describe the texture and colour changes of chicken sausage during superheated steam cooking. Chicken sausages were cooked at temperature ranging from 150-200°C with treatment times ranging from 2-6 mins. The texture profile was evaluated in terms of hardness, cohesiveness, gumminess, and chewiness, while the colour parameters were estimated in terms of lightness (L*, redness (a*, yellowness (b*, and total colour difference (∆E. Experimental data showed a gradual reduction in texture parameters as cooking times and temperatures increased. The L* value of the colour showed a linear reduction with cooking condition, while the a*, b*, and ∆E values showed a contrary effects. The decrease in texture parameters and L*-value of colour parameter followed the first-order kinetic model. While, zero-order kinetic model was adapted to fit the a* and b*. The modified first order kinetic showed a good fit for total ∆E. Significant correlations between colour and texture parameters were observed, which showed that a* alone could be used to predict the texture of chicken sausage.

  14. Experimental Research on Mass Transfer Coefficient in Liquid-Liquid Flow Boundary Layer%液-液流动边界层传质系数的实验研究

    Institute of Scientific and Technical Information of China (English)

    李明明; 李强; 李琳; 邹宗树

    2012-01-01

    为了研究冶金反应器内渣-金界面的传质,设计了研究液-液流动边界层传质实验.实验在保证油-水界面稳定的情况下,研究了苯甲酸钠示踪物质在油-水界面的传质现象.通过改变水流量Q(0.44~1.60m3/h),利用电导率仪测量苯甲酸钠示踪物质在水中的浓度变化,实验确定了液-液界面流动边界层传质系数的准数方程式,并尝试性地给出了液体黏度以及表面张力与传质系数之间的准数关系式.实验结果与液体流过平板边界层的传质过程作了比较讨论.%Experiment research concerning the mass transfer of flowing boundary layer on a liquid-liquid interface was performed to discuss the mass transfer on the molten slag-metal interface in metallurgical reactor.The mass transfer phenomenon of sodium benzoate on the oil-water interface was analyzed in the condition of keeping oil-water interface flat.The concentration change of sodium benzoate with time in water was measured by conductivity meter when the volume flow of water varied from 0.44 to 1.60 m3/h.A dimensionless number equation with respect to the mass transfer coefficient of flowing boundary layer on the liquid-liquid interface was obtained.Then,a dimensionless number equation between the mass transfer coefficient and viscosity as well as surface tension was given tentatively.The results were compared with the mass transfer of boundary layer in the case of fluid flowing through a flat.

  15. Impact of liquid water on oxygen reaction in cathode catalyst layer of proton exchange membrane fuel cell: A simple and physically sound model

    Science.gov (United States)

    Zhang, Xiaoxian; Gao, Yuan

    2016-06-01

    When cells work at high current density, liquid water accumulates in their catalyst layer (CL) and the gaseous oxygen could dissolve into the water and the ionomer film simultaneously; their associated dissolved concentrations in equilibrium with the gaseous oxygen are also different. Based on a CL acquired using tomography, we present new methods in this paper to derive agglomerate models for partly saturated CL by viewing the movement and reaction of the dissolved oxygen in the two liquids (water and ionomer) and the agglomerate as two independent random processes. Oxygen dissolved in the water moves differently from oxygen dissolved in the ionomer, and to make the analysis tractable, we use an average distribution function to describe the average movement of all dissolved oxygen. A formula is proposed to describe this average distribution function, which, in combination with the exponential distribution assumed in the literature for oxygen reaction, leads to a simple yet physically sound agglomerate model. The model has three parameters which can be directly calculated from CL structure rather than by calibration. We explain how to calculate these parameters under different water contents for a given CL structure, and analyse the impact of liquid water on cell performance.

  16. Leidenfrost Vapor Layer Stabilization on Superhydrophobic Surfaces

    Science.gov (United States)

    Vakarelski, Ivan; Patankar, Neelesh; Marston, Jeremy; Chan, Derek; Thoroddsen, Sigurdur

    2012-11-01

    We have performed experiments to investigate the influence of the wettability of a superheated metallic sphere on the stability of a thin vapor layer during the cooling of a sphere immersed in water. For high enough sphere temperatures, a continuous vapor layer (Leidenfrost regime) is observed on the surface of non-superhydrophobic spheres, but below a critical sphere temperature the layer becomes unstable and explosively switches to nuclear boiling regime. In contrast, when the sphere surface is textured and superhydrophobic, the vapor layer is stable and gradually relaxes to the sphere surface until the complete cooling of the sphere, thus avoiding the nuclear boiling transition altogether. This finding could help in the development of heat exchange devices and of vapor layer based drag reducing technologies.

  17. Single kaolinite nanometer layers prepared by an in situ polymerization-exfoliation process in the presence of ionic liquids.

    Science.gov (United States)

    Letaief, Sadok; Leclercq, Jérôme; Liu, Yun; Detellier, Christian

    2011-12-20

    A simple chemical route for the exfoliation of kaolinite in the presence of polymerizable ionic liquids and the resulting obtainment of exfoliated nanocomposites is reported. The exfoliation was achieved using three different ionic liquids structurally bearing a vinyl group: 1-methyl-3-(4-vinylbenzyl)imidazolium chloride salt (IL_1), 1-methyl-1-(4-vinylbenzyl)pyrrolidinium chloride (IL_2), and 1-methyl-3-vinyl imidazolium iodide (IL_3) and a urea-kaolinite intercalate as precursor. The reaction was done in one step by an in situ polymerization-exfoliation process. (13)C CP/MAS NMR spectra confirmed the spontaneous polymerization of the ionic liquid during the exfoliation process to afford atactic polystyrene derivatives in the case of IL_1 and IL_2. The amount of organic material in the exfoliated nanocomposite was close to 30% as shown by thermal gravimetric analysis. This amount is small in comparison to the amount obtained when the exfoliation was done using sodium polyacrylate (Letaief and Detellier, Langmuir2009, 25, 10975). XRD as well as SEM analysis confirmed a total exfoliation of the kaolinite when the reaction was done using urea kaolinite, whereas a microcomposite, made predominantly of kaolinite platelet aggregates dispersed in the polymeric matrix, was formed when dimethylsulfoxide kaolinite was used as the precursor.

  18. Effect of boundaries on the dynamic interaction of a liquid-filled porous layer and a supporting continuum

    Indian Academy of Sciences (India)

    M Tajuddin; G Narayan Reddy

    2005-08-01

    A transcendental equation is derived relating wave number and phase velocity of propagation of waves in a partially saturated layered half-space under plane strain conditions. The period equation is derived and discussed for two types of boundaries, permeable and impermeable. In the limiting cases, the problem reduces to more simplified forms as discussed by earlier researchers.

  19. A coupled melt-freeze temperature index approach in a one-layer model to predict bulk volumetric liquid water content dynamics in snow

    Science.gov (United States)

    Avanzi, Francesco; Yamaguchi, Satoru; Hirashima, Hiroyuki; De Michele, Carlo

    2016-04-01

    Liquid water in snow rules runoff dynamics and wet snow avalanches release. Moreover, it affects snow viscosity and snow albedo. As a result, measuring and modeling liquid water dynamics in snow have important implications for many scientific applications. However, measurements are usually challenging, while modeling is difficult due to an overlap of mechanical, thermal and hydraulic processes. Here, we evaluate the use of a simple one-layer one-dimensional model to predict hourly time-series of bulk volumetric liquid water content in seasonal snow. The model considers both a simple temperature-index approach (melt only) and a coupled melt-freeze temperature-index approach that is able to reconstruct melt-freeze dynamics. Performance of this approach is evaluated at three sites in Japan. These sites (Nagaoka, Shinjo and Sapporo) present multi-year time-series of snow and meteorological data, vertical profiles of snow physical properties and snow melt lysimeters data. These data-sets are an interesting opportunity to test this application in different climatic conditions, as sites span a wide latitudinal range and are subjected to different snow conditions during the season. When melt-freeze dynamics are included in the model, results show that median absolute differences between observations and predictions of bulk volumetric liquid water content are consistently lower than 1 vol%. Moreover, the model is able to predict an observed dry condition of the snowpack in 80% of observed cases at a non-calibration site, where parameters from calibration sites are transferred. Overall, the analysis show that a coupled melt-freeze temperature-index approach may be a valid solution to predict average wetness conditions of a snow cover at local scale.

  20. Superheated Steam Reasonable Application in the Papermaking Process%过热蒸气在造纸过程中的合理应用

    Institute of Scientific and Technical Information of China (English)

    刘建蒙; 陈巧花; 徐国华; 何小星

    2013-01-01

    文章以过热蒸气为对象,通过比较减温减压点不同,分析管径、壁厚、法兰、流速的变化,过热蒸气和饱和蒸气在运输过程中的能耗及运输管道成本.结果表明在输送过程中输送过热蒸气是最合理的,也是经济的.分析过热蒸气对钢材的强度、热膨胀、过度热应力的影响,说明过热蒸气影响设备安全性和寿命.%Superheated steam was taken as a research object, through analyzing the variety of pipe diameter, wall thickness, flange and flow changes under different temperature and pressure reduction, superheated steam and saturated steam were compared in energy consumption and piping costs during transportation process. The results show that superheated steam is the most reasonable, and also economical in the transportation process. Through analysis of superheated steam effecting on the strength steel, thermal expansion and excessive thermal stress, it illustrates that the superheated steam affects the equipment's safety and life.

  1. Carbon gel assisted low temperature liquid-phase synthesis of C-LiFePO4/graphene layers with high rate and cycle performances

    Science.gov (United States)

    Tang, Hongwei; Si, Yanli; Chang, Kun; Fu, Xiaoning; li, Bao; Shangguan, Enbo; Chang, Zhaorong; Yuan, Xiao-Zi; Wang, Haijiang

    2015-11-01

    Nano-scale LiFePO4/graphene oxide (GO) as cathode materials for lithium ion batteries has been successfully synthesized via a one-step carbon gel assisted liquid-phase approach at a low-temperature (108 °C) and normal pressure. C-LiFePO4/graphene layers (G) composites, composed of LiFePO4, amorphous carbon and graphene layers, are then produced after rapid high temperature carbon treatment. Interface tunnel effect, produced by the intimate contact of LiFePO4 particles with amorphous carbon and graphene layers, greatly improves the properties of the composites. Electrochemical tests indicate that the optimal amount of GO addition is 1 wt.% in terms of achieving a high electrochemical performance of the C-LiFePO4/G composites. Discharge capacity of the C-LiFePO4/G composites is 160.0 mAh g-1 at 0.2 C. When the current rate is further increased to 60 C, the discharge capacity of C-LiFePO4/G can reach 68 mAh g-1. At a high current rate of 20 C, the capacity attenuation rate of the C-LiFePO4/G electrode is only 9.6% after 200 cycles, showing excellent high-rate discharge capability and cycle performance. This is achieved under a facile synthesis condition of a simple procedure, low temperature, and normal pressure.

  2. Thermal and hydrodynamic study of a whirling liquid hydrogen layer under high heat flux; Etude thermique et hydrodynamique d'une couche tourbillonnaire d'hydrogenen liquide sous flux de chaleur eleve

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-03-01

    In order to achieve a cold neutrons source ({lambda} {>=} 4.10{sup -10} m) in a high flux reactor ({approx} 10{sup 15} neutrons/cm{sup 2}.s), a whirling liquid hydrogen layer (145 mm OD, effective thickness 15 mm, height about 180 mm) was formed, out-of-pile, in a cylindrical transparent glass vessel. The whirling motion was obtained by tangential injection of the liquid, near the wall. Thermal and hydrodynamical conditions of formation and laws of similarity of such a layer were studied. The characteristics of this whirling flow were observed as a function of mass flow rate (5 to 27 g/s; 4.3 to 23 l/mn), and of spillway width (18 and 25 mm). Six different nozzles were used : 1.0; 1.5; 1.9; 2.25; 2.65 and 3.0 mm ID. The total heat influx was found between 8.6 and 10.4 kW. The heat flux density was about 9.4 W/cm{sup 2} and the mean layer density around 80 per cent of that of the liquid hydrogen at 20.4 Kelvin. High speed movies were used to analyze the boiling regime. (author) [French] En vue de realiser une source de neutrons froids ({lambda} {>=} 4.10{sup -10} m) dans un reacteur a haut flux ({approx} 10{sup 15} neutrons thermiques/cm{sup 2}.s), on a forme dans un vase cylindrique transparent en verre, hors-pile, une couche tourbillonnaire ('vortex') d'hydrogene liquide (diametre exterieur 145 mm, epaisseur effective 15 mm, hauteur 180 mm environ). Le mouvement giratoire est obtenu par injection tangentielle du liquide pres de la paroi. L'etude porte sur la determination des conditions thermiques et hydrodynamiques de la formation d'une telle couche et sur les regles de similitude de ce phenomene. On a observe les caracteristiques de l'ecoulement giratoire en fonction du debit (de 5 a 27 g/s, soit de 4.3 a 23 1/mn), de la vitesse d'injection (entre 10 et 110 m/s) et de la largeur du deversoir (18 et 25 mm), ceci pour six diametres differents d'injecteur (1.0 ; 1.5; 1.9; 2.25; 2.65 et 3.0 mm). Le flux de chaleur total mesure

  3. Pengembangan Proses Produksi Biodiesel Biji Karet Metode Non-Katalis Superheated Methanol pada Tekanan Atmosfir

    Directory of Open Access Journals (Sweden)

    I Wayan Susila

    2009-01-01

    Full Text Available The process of biodiesel production from rubber seed (hevea brasiliensis is conducted in Indonesia in general using catalyst (acid or alkaline and wet washing method or dry washing method. Catalyst method brings many weaknesses include: a long production time, high production costs due to wear or magnesol as a catalyst absorban, especially if the purification uses water (wet wash system because it will be harmful to engine components such as: seal leaks quickly, easily arise fungus, rust/corrosion on the cylinder heads, pumps and fuel filters are often clogged, etc. Biodiesel production process with non-catalytic method can overcome the weaknesses mentioned above. In this study, rubber seed oil is obtained by the method of pressing.The oil specifications are as follow: viscosity 5.19 cSt, density 0.9209 g/ml, water content 0.2%, free fatty acid (FFA 6.66%, and the boiling point 305 oC.The methodology used is processing rubber seed into biodiesel with superheated methanol non-catalyst method. Transesterification performed in a Bubble Column Reactor (BCR at the reaction temperature 270oC, 275oC, 280oC, 285oC, and 290 oC and held at atmospheric pressure. The molar ratio of methanol and rubber seed oil were: 140, 150, and 160. The results showed that the process of making biodiesel from vegetable oil catalyst method is usually carried out through the various stages of the process e.g: degumming process to remove mucus or sap it contains, esterification to reduce the FFA content to below 2,5% to prevent saponification, and tranesterification to obtain methyl esters or biodiesel and then washing. But in its development by using non-catalytic method turns out that the rubber seed oil has a high FFA content (above 2.5% can be directly processed tranesterification without any saponification formed and can produce biodiesel without having to experience the process of degumming, esterification and washing. The density, cetane number, pour point, flash

  4. Orientating layers with adjustable pretilt angles for liquid crystals deposited by a linear atmospheric pressure plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Jian, Shih-Jie; Kou, Chwung-Shan [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Hwang, Jennchang [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lee, Chein-Dhau; Lin, Wei-Cheng [Material and Chemical Research Laboratories/Industrial Technology Research Institute, Hsinchu 30140, Taiwan (China)

    2013-06-15

    A method for controlling the pretilt angles of liquid crystals (LC) was developed. Hexamethyldisiloxane polymer films were first deposited on indium tin oxide coated glass plates using a linear atmospheric pressure plasma source. The films were subsequently treated with the rubbing method for LC alignment. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements were used to characterize the film composition, which could be varied to control the surface energy by adjusting the monomer feed rate and input power. The results of LC alignment experiments showed that the pretilt angle continuously increased from 0 Degree-Sign to 90 Degree-Sign with decreasing film surface energy.

  5. Liquid-based thin-layer cytology can be routinely used in samples obtained via fiberoptic bronchoscope.

    Science.gov (United States)

    Kobayashi, Yukihiro; Uehara, Takeshi; Ota, Hiroyoshi

    2011-01-01

    The aim of this study was to evaluate liquid-based preparations (LBP) as a replacement for conventional smears (CS) of bronchial brushing (BB) and transbronchial fine-needle aspiration (TBNA) samples obtained via fiberoptic bronchoscope. Bronchial brushing and TBNA samples were obtained from 62 and 33 patients by fiberoptic bronchoscopy, respectively. Liquid-based preparations were prepared from needle rinse after initial CS preparation. We compared cellularity, cell morphology, and background between the LBP and CS slides. Correspondence rates between LBP and CS diagnoses in the above 3 categories were 90.3% in the BB and 97.0% in the TBNA samples. If suspicious cases were regarded as malignant, correspondence rates reached 98.4 and 100%, respectively. Histological diagnoses by LBP were mostly the same as those by CS and by biopsy or operation samples. Morphologically, cells and nuclei were shrunk in the LBP; however, the shrinking was not severe enough to influence cytological diagnoses. Blood background and air-drying, which were observed on many of the CS slides, were not detected on the LBP slides. It is possible to use LBP for routine laboratory processing of BB and TBNA samples as a replacement for CS. Copyright © 2010 S. Karger AG, Basel.

  6. Halogen-Free Phosphonate Ionic Liquids as Precursors of Abrasion Resistant Surface Layers on AZ31B Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Tulia Espinosa

    2015-01-01

    Full Text Available Surface coatings formed by immersion in the ionic liquids (ILs 1,3-dimethylimidazolium methylphosphonate (LMP101, 1-ethyl-3-methylimidazolium methylphosphonate (LMP102 and 1-ethyl-3-methylimidazolium ethylphosphonate (LEP102 on magnesium alloy AZ31B at 50 °C have been studied. The purpose of increasing the temperature was to reduce the immersion time, from 14 days at room temperature, to 48 hours at 50 °C. The abrasion resistance of the coated alloy was studied by microscratching under progressively increasing load, and compared with that of the uncoated material. The order of abrasion resistance as a function of the IL is LEP102 > LMP101 > LMP102, which is in agreement with the order obtained for the coatings grown at room temperature. The maximum reduction in penetration depth with respect to the uncovered alloy, of a 44.5%, is obtained for the sample treated with the ethylphosphonate LEP102. However, this reduction is lower than that obtained when the coating is grown at room temperature. This is attributed to the increased thickness and lower adhesion of the coatings obtained at 50 °C, particularly those obtained from methylphosphonate ionic liquids. The results are discussed from SEM-EDX and profilometry.

  7. Application of the BINS superheated drop detector spectrometer to the {sup 9}Be(p,xn) neutron energy spectrum determination

    Energy Technology Data Exchange (ETDEWEB)

    Di Fulvio, A.; Ciolini, R.; Mirzajani, N.; Romei, C.; D' Errico, F. [Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione, Universita di Pisa, Pisa (Italy); Bedogni, R. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Esposito, J.; Zafiropoulos, D.; Colautti, P. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy)

    2013-07-18

    In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the {sup 9}Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.

  8. Nonmixing layers

    Science.gov (United States)

    Gaillard, Pierre; Giovangigli, Vincent; Matuszewski, Lionel

    2016-12-01

    We investigate the impact of nonideal diffusion on the structure of supercritical cryogenic binary mixing layers. This situation is typical of liquid fuel injection in high-pressure rocket engines. Nonideal diffusion has a dramatic impact in the neighborhood of chemical thermodynamic stability limits where the components become quasi-immiscible and ultimately form a nonmixing layer. Numerical simulations are performed for mixing layers of H2 and N2 at a pressure of 100 atm and temperature around 120-150 K near chemical thermodynamic stability limits.

  9. Effect of the ion-beam bombardment and annealing temperature on sol-gel derived yttrium aluminum oxide film as liquid crystal alignment layer

    Science.gov (United States)

    Jeong, Hae-Chang; Heo, Gi-Seok; Kim, Eun-Mi; Lee, Ju Hwan; Han, Jeong-Min; Seo, Dae-Shik

    2017-02-01

    We demonstrated a homogeneous liquid-crystal (LC) alignment state on yttrium aluminum oxide (YAlO) films, where the alignment was induced by ion-beam (IB) irradiation. Topographical analysis was performed by atomic force microscopy as a function of annealing temperature. Higher annealing temperatures yielded a smoother surface, accompanied by reduced light scattering. Transparency in the visible region increased on the surface fabricated at higher annealing temperatures. LC alignment mechanism was determined by X-ray diffraction (XRD) analysis. Moreover, IB-irradiated YAlO films annealed at temperatures greater than 200 °C exhibited good thermal stability and low capacitance-voltage hysteresis. The IB-irradiated YAlO films are suitable as alternative alignment layers in advanced LC display applications.

  10. The Effect of Contact Angle on Dynamics of Dry Spots Spreading in a Horizontal Layer of Liquid at Local Heating

    Directory of Open Access Journals (Sweden)

    Zaitsev D.V.

    2015-01-01

    Full Text Available The effect of equilibrium contact angle on dynamics of dry spot spreading at disruption of a horizontal water layer heated locally from the substrate was studied using the high-speed Schlieren technique. Different methods of working surface processing were applied; this allowed variations of the equilibrium contact angle from 27±6° to 74±9° without a change in thermal properties of the system. It is found out that substrate wettability significantly affects the propagation velocity of dry spot and its final size. It is also found out that the velocity of contact line propagation is higher in the areas of substrate with a higher temperature.

  11. Super-fast switching of twisted nematic liquid crystals with a single-wall-carbon-nanotube-doped alignment layer

    Science.gov (United States)

    Liu, Yang; Lim, Young Jin; Kundu, Sudarshan; Lee, Seung Hee; Lee, Gi-Dong

    2015-03-01

    The application of a single-wall carbon-nanotube (SWCNT) and polyimide (PI) composite thin film on an indium tin-oxide (ITO) glass substrate, working as the command surface in a twisted nematic liquid crystal display (LCD), is described. SWCNTs were chopped and oxidized in a strong acid medium to make them more miscible in a polyimide solution. A film of this newly-developed PISWCNT composite was rubbed to determine the director direction for the LC molecules. The newlyfabricated command surface was examined using a laser beam profiler and atomic force microscopy. Sizes of shortened SWCNTs were characterized by using field-emission scanning electron microscopy (FE-SEM). Finally, small-sized test panels were fabricated from this composite-coated ITO glass, and their electro-optic performances were measured. Although the operating voltage to switch a cell was increased by around 41%, the switching speed was improved remarkably. The rise time of the test cells was found to be improved by around 10.12% and the decay time by around 29.77%. Thus, an overall improvement of around 16.12% in the total switching time was achieved. The change in the surface morphology of the newly-developed composite materials was found to be one of the factors responsible for the faster switching of the device. Detailed discussions are given in this report to explain the faster switching of the newly-developed twisted nematic liquid crystal display (TN-LCD). The device can be useful for practical applications.

  12. Influence of the adsorption layers of surfactants on the extraction behaviour of heavy metals. Liquid-liquid extraction; Einfluss von Tensidadsorptionsschichten auf das Extraktionsverhalten von Schwermetallen. T. 1. Fluessig/fluessig-Extraktion

    Energy Technology Data Exchange (ETDEWEB)

    Raatz, S.; Haertel, G. [Technische Univ. Bergakademie Freiberg (Germany). Lehrstuhl fuer Umweltverfahrenstechnik

    1998-05-01

    Depending on the type of the head group (anionic, cationic and nonionic) as well as the structure the adsorption layers of surfactants on the liquid/liquid interface have an essential influence on the extraction behavior and the mass transfer of heavy metals (Cd, Zn, Pb, Cr). By choosing the right type and concentration of surfactant it should therefore be possible to accelerate the mass transfer thus improving the extraction rate (e.g. sodium dodecylsulfonate), or even to prevent a mass transfer almost completely (e.g. i-octylphenyl ethoxylate). The purpose of this paper is to control the selectivity of the mass-transfer accompanied by reaction beyond fluid interfaces with the help of surfactants as well as to clarify the effective mechanisms. (orig.) [Deutsch] Tensidadsorptionsschichten haben in Abhaengigkeit von der Art ihrer Kopfgruppierung (anionisch, kationisch und nichtionisch), Struktur und Konzentration einen wesentlichen Einfluss auf das Extraktionsverhalten bzw. den Stoffuebergang von Schwermetallen (Cd, Zn, Pb, Cr) ueber die Fluessig/fluessig-Phasengrenze. Mit der richtigen Wahl eines Tensids (Art, Konzentration) ist es daher moeglich, den Stofftransport zu beschleunigen und den Extraktionsgrad bedeutend zu verbessern (z.B. Na-Dodecylsulfonat) oder auch den Stofftransport nahezu zu unterbinden (z.B. i-Octylphenylethoxylat) oder auch den Stofftransport nahezu zu unterbinden (z.B. i-Octylphenylethoxylat). Das Ziel dieser Arbeit ist es, die Selektivitaet der reaktiven Stoffuebertragung ueber fluide Phasengrenzen durch entsprechend gewaehlte Adsorptionsschichten gezielt zu steuern und die dabei wirkenden Mechanismen aufzuklaeren. (orig.)

  13. Butanol Dehydration over V2O5-TiO2/MCM-41 Catalysts Prepared via Liquid Phase Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Jong-Ki Jeon

    2013-04-01

    Full Text Available MCM-41 was used as a support and, by using atomic layer deposition (ALD in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics of the TiO2-V2O5/MCM-41 catalysts were analyzed using XRF, BET, NH3-TPD, XRD, Py-IR, and XPS. The dehydration reaction of butanol was performed in a fixed bed reactor. For the samples with vanadium oxide loaded to TiO2/MCM-41 sample using the liquid phase ALD method, it was possible to increase the loading amount until the amount of vanadium oxide reached 12.1 wt %. It was confirmed that the structural properties of the mesoporous silica were retained well after titanium oxide and vanadium loading. The NH3-TPD and Py-IR results indicated that weak acid sites were produced over the TiO2/MCM-41 samples, which is attributed to the generation of Lewis acid sites. The highest activity of the V2O5(12.1-TiO2/MCM-41 catalyst in 2-butanol dehydration is ascribed to it having the highest number of Lewis acid sites, as well as the highest vanadium dispersion.

  14. Electrochemical sensor for bisphenol A based on ionic liquid functionalized Zn-Al layered double hydroxide modified electrode.

    Science.gov (United States)

    Zhan, Tianrong; Song, Yang; Li, Xianjun; Hou, Wanguo

    2016-07-01

    The plate-like Zn-Al layered double hydroxide modified with 1-aminopropyl-3-methylimidzaolium tetrafluoroborate (named as ILs-LDH) was synthesized by coprecipitation method. Several techniques confirmed the layered structure of ILs-LDH with a disk-like morphology. A novel electrochemical sensor based on ILs-LDH modified glass carbon electrode (GCE) was developed for bisphenol A (BPA) determination. Experimental factors including modified content, pH, scan rate, accumulation time and potential had been carefully optimized. ILs-LDH/GCE performed the excellent electro-oxidation ability toward BPA with the more negative oxidation overpotential and larger peak current than bare GCE or LDH/GCE. Differential pulse voltammetry determination of BPA afforded a wider linear range from 0.02 to 3μM with the detection limit of 4.6nM (S/N=3). The fabricated sensor demonstrated an acceptable reproducibility, good stability and high sensitivity. The proposed method was successfully used to detect BPA in real water samples with satisfactory recovery ranging from 94.9% to 102.0%.

  15. Study on the Thickness Change of Nickel-Plated Layer in Fabrication of the Silver Hollow Nickel Waveguides by the Outer-Coating Method of the Liquid Phase Process

    OpenAIRE

    2016-01-01

    A metallic hollow waveguide is promising fiber for the delivery of laser radiation. Thickness of the nickel plated layer for supporting of the waveguide in fabrication of a dielectric coated silver hollow nickel waveguide is very important factor. In this paper, the change characteristic in the thickness of the nickel plated layer along the length of the silver coated glass mandrel during fabricating the silver hollow nickel waveguide by the outer-coating method of the liquid phase process ha...

  16. Multiphase modeling of nitrate photochemistry in the quasi-liquid layer (QLL: implications for NOx release from the Arctic and coastal Antarctic snowpack

    Directory of Open Access Journals (Sweden)

    A. Saiz-Lopez

    2008-08-01

    Full Text Available We utilize a multiphase model, CON-AIR (Condensed Phase to Air Transfer Model, to show that the photochemistry of nitrate (NO3− in and on ice and snow surfaces, specifically the quasi-liquid layer (QLL, can account for NOx volume fluxes, concentrations, and [NO]/[NO2] (γ=[NO]/[NO2] measured just above the Arctic and coastal Antarctic snowpack. Maximum gas phase NOx volume fluxes, concentrations and γ simulated for spring and summer range from 5.0×104 to 6.4×105 molecules cm−3 s−1, 5.7×108 to 4.8×109 molecules cm−3, and ~0.8 to 2.2, respectively, which are comparable to gas phase NOx volume fluxes, concentrations and γ measured in the field. The model incorporates the appropriate actinic solar spectrum, thereby properly weighting the different rates of photolysis of NO3− and NO2−. This is important since the immediate precursor for NO, for example, NO2−, absorbs at wavelengths longer than nitrate itself. Finally, one-dimensional model simulations indicate that both gas phase boundary layer NO and NO2 exhibit a negative concentration gradient as a function of height although [NO]/[NO2] are approximately constant. This gradient is primarily attributed to gas phase reactions of NOx with halogens oxides (i.e. as BrO and IO, HOx, and hydrocarbons, such as CH3O2.

  17. Dissolvable layered double hydroxide coated magnetic nanoparticles for extraction followed by high performance liquid chromatography for the determination of phenolic acids in fruit juices.

    Science.gov (United States)

    Saraji, Mohammad; Ghani, Milad

    2014-10-31

    A magnesium-aluminum layered double hydroxide coated on magnetic nanoparticles was synthesized and used as a sorbent to extract some phenolic acids including p-hydroxy benzoic acid, caffeic acid, syringic acid, p-coumaric acid and ferulic acid from fruit juices. After extraction, the elution step was performed through dissolving double hydroxide layers containing the analytes by changing the solution pH. The extracted phenolic acids were separated and quantified using high performance liquid chromatography-photodiode array detection. Experimental parameters such as sorbent amount, solution pH, desorption solvent volume and extraction time were studied and optimized. The linearity range of the method was between 2 and 500μgL(-1) with the determination coefficient (r(2)) higher than 0.991. Relative standard deviations for intra- and inter-day precision for the analytes at 100μgL(-1) were in the range of 4.3-9.2% and 4.9-8.6%, respectively. Batch-to-batch reproducibility at 100μgL(-1) concentration level was in the range of 7.8-11% (n=3). The limits of detection were between 0.44 and 1.3μgL(-1). Relative recoveries higher than 81% with RSDs in the range of 4.2-9.7% were obtained in the analysis of fruit juice samples.

  18. Helfrich model of membrane bending: from Gibbs theory of liquid interfaces to membranes as thick anisotropic elastic layers.

    Science.gov (United States)

    Campelo, Felix; Arnarez, Clement; Marrink, Siewert J; Kozlov, Michael M

    2014-06-01

    Helfrich model of membrane bending elasticity has been most influential in establishment and development of Soft-Matter Physics of lipid bilayers and biological membranes. Recently, Helfrich theory has been extensively used in Cell Biology to understand the phenomena of shaping, fusion and fission of cellular membranes. The general background of Helfrich theory on the one hand, and the ways of specifying the model parameters on the other, are important for quantitative treatment of particular biologically relevant membrane phenomena. Here we present the origin of Helfrich model within the context of the general Gibbs theory of capillary interfaces, and review the strategies of computing the membrane elastic moduli based on considering a lipid monolayer as a three-dimensional thick layer characterized by trans-monolayer profiles of elastic parameters. We present the results of original computations of these profiles by a state-of-the-art numerical approach.

  19. Experimental Attempts to Investigate the Influence of Petrographic Properties on Drying Characteristics of Lignite in Superheated Steam Atmosphere

    Directory of Open Access Journals (Sweden)

    Anna Sciazko

    2016-05-01

    Full Text Available A superheated steam fluidized bed dryer (SSFBD in a self-heat recuperative configuration has a great potential of improving thermal efficiency of a lignite-fired power plant by recovering both of latent heat of vaporization of water kept in the fuel and part of sensible heat during the fuel processing. However, the optimal design of the dryer requires the fundamental knowledge of drying characteristics in respect to the individual properties of the utilized fuel. Experimental investigation to determine the correlation between a specific coal properties originated from geological background and its drying characteristics is thus the major concern in this paper. The investigated lignite is a representative of Turoszow deposit in Poland. Experimental attempts unveiling drying kinetics were carried out for 5 mm and 10 mm diameter spherical samples in the superheated steam atmosphere in the temperature range of 110 °C–170 °C. Simultaneous and continuous measurements of changes in weight, surface and interior temperatures and appearance on each tested sample were carried out for describing drying behavior. Analytical investigation was applied to explain the drying characteristics, which are strongly affected by the individual properties of coal and the inherent ash composition.

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

    Directory of Open Access Journals (Sweden)

    Robert F. Tournier

    2014-08-01

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

  1. Interferometric and numerical study of the temperature field in the boundary layer and heat transfer in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Lucic, Anita; Emans, Maximilian; Mayinger, Franz; Zenger, Christoph

    2004-04-01

    An interferometric study and a numerical simulation are presented of the combined process of the bulk turbulent convection and the dynamic of a vapor bubble which is formed in the superheated boundary layer of a subcooled flowing liquid, in order to determine the heat transfer to the flowing subcooled liquid. In this investigation focus has been given on a single vapor bubble at a defined cavity site to provide reproducible conditions. In the experimental study single bubbles were generated at a single artificial cavity by means of a CO{sub 2}-laser as a spot heater at a uniformly heated wall of a vertical rectangular channel with water as the test fluid. The experiments were performed at various degrees of subcooling and mass flow rates. The bubble growth and the temporal decrease of the bubble volume were captured by means of the high-speed cinematography. The thermal boundary layer and the temperature field at the phase-interface between fluid and bubble were visualized by means of the optical measurement method holographic interferometry with a high temporal and spatial resolution, and thus the local and temporal heat transfer could be quantified. The experimental results form a significant data basis for the description of the mean as well as the local heat transfer as a function of the flow conditions. According to the experimental configuration and the obtained data the numerical simulations were performed. A numerical method has been developed to simulate the influence of single bubbles on the surrounding fluid which is based on a Lagrangian approach to describe the motion of the bubbles. The method is coupled to a large-eddy simulations by the body force term which is locally evaluated based on the density field. The obtained experimental data correspond well with the numerical predictions, both of which demonstrate the thermo- and fluiddynamic characteristics of the interaction between the vapor bubble and the subcooled liquid.

  2. Study on the Thickness Change of Nickel-Plated Layer in Fabrication of the Silver Hollow Nickel Waveguides by the Outer-Coating Method of the Liquid Phase Process

    CERN Document Server

    Ro, Sok-Bong; Kim, Uo-Hyon

    2016-01-01

    A metallic hollow waveguide is promising fiber for the delivery of laser radiation. Thickness of the nickel plated layer for supporting of the waveguide in fabrication of a dielectric coated silver hollow nickel waveguide is very important factor. In this paper, the change characteristic in the thickness of the nickel plated layer along the length of the silver coated glass mandrel during fabricating the silver hollow nickel waveguide by the outer-coating method of the liquid phase process has been studied both experimentally and analytically. Waveguides with uniform thickness of the nickel plated layer along the length of the silver coated glass mandrel have been fabricated.

  3. Modification of technological control units for superheated steam temperature at 210-MW power units of the Primor'ye Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    V.V. Slesarenko; A.A. Belousov; V.V. Milush [Far East State Engineering University, Vladivostok (Russian Federation)

    2008-06-15

    The results of analysis of operation of the temperature control system for superheated steam at the BKZ-670-140F boilers of the Primor'ye Power Plant (GRES) are presented. The possibility of updating of the injection system to improve the reliability and economic efficiency of power units of electric power plants is considered.

  4. Modification of technological control units for superheated steam temperature at 210-MW power units of the Primor'ye Power Plant

    Science.gov (United States)

    Slesarenko, V. V.; Belousov, A. A.; Milush, V. V.

    2008-06-01

    The results of analysis of operation of the temperature control system for superheated steam at the BKZ-670-140F boilers of the Primor’ye Power Plant (GRES) are presented. The possibility of updating of the injection system to improve the reliability and economic efficiency of power units of electric power plants is considered.

  5. Generation of nanocrystalline surface layer in short pulse laser processing of metal targets under conditions of spatial confinement by solid or liquid overlayer

    Science.gov (United States)

    Shugaev, Maxim V.; Shih, Cheng-Yu; Karim, Eaman T.; Wu, Chengping; Zhigilei, Leonid V.

    2017-09-01

    The effect of spatial confinement by a solid or liquid overlayer on short pulse laser-induced surface microstructure modification is investigated in a series of large-scale atomistic simulations performed for Ag targets irradiated in the regime of melting and resolidification, below the thresholds for laser spallation and ablation. For Ag targets with free surfaces, the formation of a nanocrystalline region with random crystallographic grain orientation is observed under irradiation conditions leading to the generation of numerous sub-surface voids that slow down the solidification process. When no voids are generated, the resolidification produces grains misoriented with respect to the bulk of the target by just several degrees and separated from each other by low angle grain boundaries or dislocation walls. The presence of a liquid or solid overlayer suppresses nucleation of sub-surface voids, provides an additional pathway for cooling through the heat conduction to the overlayer, and facilitates the formation of nanocrystalline structure in a region of the metal target adjacent to the overlayer. Moreover, the stabilizing effect of the solid overlayer may result in an incomplete melting of metal in the vicinity of the interface, making it possible for grains growing from the interface to retain ;memory; of the target orientation and to produce nanocrystalline interfacial region with small misorientation of grains with respect to the bulk of the target. In all simulations, the nanocrystalline layers generated by laser processing of single crystal Ag targets are characterized by a high density of stacking faults, twin boundaries, and point defects produced in the course of the rapid resolidification.

  6. Development of a low cost 94GHz imaging receiver using multi-layer liquid crystal polymer technology

    Science.gov (United States)

    Rice, Paul J.; Black, Mark; McNicol, John; Munday, Paul D.; Adamson, Kate; Smethurst, Lee

    2008-04-01

    The 94GHz imaging band is the most commercially focused of the mm-wave imaging "windows". However, the commercial uptake of imaging systems has been limited due to the production costs involved, of which a significant proportion is due to the front-end receivers. Conventionally, the receiver is machined from metal and made-up of either several modules or a single more integrated module containing the RF and DC circuitry. Even with the more integrated approach the cost is prohibitive, due to the cost of the MMICs, the machining of the metal and integration of different materials during assembly. The front end receiver cost is a potential limiting factor in the deployment of imaging systems. LCP multi-layer substrates remove the requirement for expensive metal machining and because the RF and DC circuitry is integrated in the same substrate the assembly cost of the module is also reduced. Cost is not the only consideration, LCP has excellent properties which are especially attractive for high-performance microwave applications. These properties include low permittivity, low loss tangent, low water-absorption coefficient and most importantly low cost. By means of heat treatments, their coefficients of thermal expansion can be tailored to make them more amenable to integration into packages that include other materials. The LCP is manufactured in large sheet/panel form allowing batch manufacture of circuits which ensures circuit to circuit repeatability and a high yield. LCP has a dielectric constant of 3.16+/-0.05 and a dielectric loss tangent of 0.0049 to 100GHz. These properties have resulted in measured line loss of 0.2dB/mm at 110GHz. This level of loss makes this material system a viable approach for low noise integrated imaging receivers and will allow sensitivities of <0.8°K NETD to be achieved. This paper describes the design, measurement and characterisation of the first 94GHz receiver manufactured using LCP reported in the literature.

  7. Atomic layer deposition of indium oxide thin film from a liquid indium complex containing 1-dimethylamino-2-methyl-2-propoxy ligands

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jeong Hwan, E-mail: jhan@krict.re.kr [Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-Ro, Yuseong-Gu, Daejeon 34114 (Korea, Republic of); Department of Chemical Convergence Materials, University of Science and Technology (UST), 217 Gajeong-Ro, Yuseong-Gu, Deajeon 34113 (Korea, Republic of); Jung, Eun Ae [Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-Ro, Yuseong-Gu, Daejeon 34114 (Korea, Republic of); Department of Chemistry, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Kim, Hyo Yeon [Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-Ro, Yuseong-Gu, Daejeon 34114 (Korea, Republic of); Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-Ro, Seongdong-gu, Seoul 04763 (Korea, Republic of); Kim, Da Hye [Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-Ro, Yuseong-Gu, Daejeon 34114 (Korea, Republic of); Department of Chemistry, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Park, Bo Keun [Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-Ro, Yuseong-Gu, Daejeon 34114 (Korea, Republic of); Department of Chemical Convergence Materials, University of Science and Technology (UST), 217 Gajeong-Ro, Yuseong-Gu, Deajeon 34113 (Korea, Republic of); Park, Jin-Seong [Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-Ro, Seongdong-gu, Seoul 04763 (Korea, Republic of); Son, Seung Uk [Department of Chemistry, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); and others

    2016-10-15

    Highlights: • Novel liquid indium complex, tris(1-dimethylamino-2-methyl-2-propoxy)indium, was developed with showing excellent thermal properties. • Self-limited atomic layer deposition (ALD) of In{sub 2}O{sub 3} was realized from the newly developed indium precursor and O{sub 3} at the deposition temperatures of 150–200 °C. • The In{sub 2}O{sub 3} films grown at 150–200 °C showed carrier concentrations of 1.5 × 10{sup 18}–6.6 × 10{sup 19} cm{sup −3}, resistivities of 2 × 10{sup −3}–15.1 Ω cm, and Hall mobilities of 0.8–42 cm{sup 2}/(V s). - Abstract: In{sub 2}O{sub 3} thin films were grown from a newly developed, liquid, homoleptic, In-based complex, tris(1-dimethylamino-2-methyl-2-propoxy)indium [In(dmamp){sub 3}], and O{sub 3} by atomic layer deposition (ALD) at growth temperatures of 150–200 °C. In(dmamp){sub 3} exhibited single-step evaporation with negligible residue and excellent thermal stability between 30 and 250 °C. The self-limiting surface reaction of In{sub 2}O{sub 3} during ALD was demonstrated by varying the In(dmamp){sub 3} and O{sub 3} pulse lengths, with a growth rate of 0.027 nm/cycle achieved at 200 °C. The In{sub 2}O{sub 3} films grown at temperatures over 175 °C exhibited negligible concentrations of impurities, whereas that grown below 175 °C had concentrations of residual C of 6–8 at.%. Glancing angle X-ray diffraction revealed that the In{sub 2}O{sub 3} films were polycrystalline in nature when the deposition temperature was greater than 200 °C. The In{sub 2}O{sub 3} films grown at 150–200 °C exhibited carrier concentrations of 1.5 × 10{sup 18}–6.6 × 10{sup 19} cm{sup −3}, resistivities of 15.1–2 × 10{sup −3} Ω cm, and Hall mobilities of 0.8–42 cm{sup 2}/(V s).

  8. Qualitative and quantitative two-dimensional thin-layer chromatography/high performance liquid chromatography/diode-array/electrospray-ionization-time-of-flight mass spectrometry of cholinesterase inhibitors.

    Science.gov (United States)

    Mroczek, Tomasz

    2016-09-10

    Recently launched thin-layer chromatography-mass spectrometry (TLC-MS) interface enabling extraction of compounds directly from TLC plates into MS ion source was unusually extended into two-dimensional thin-layer chromatography/high performance liquid chromatography (2D, TLC/HPLC) system by its a direct connection to a rapid resolution 50×2.1mm, I.D. C18 column compartment followed by detection by diode array (DAD) and electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). In this way, even not separated bands of complicated mixtures of natural compounds could be analysed structurally, only within 1-2min after development of TLC plates. In comparison to typically applied TLC-MS interface, no ion suppression for acidic mobile phases was observed. Also, substantial increase in ESI-TOF-MS sensitivities and quality of spectra, were noticed. It has been utilised in combination with TLC- based bioautographic approaches of acetylcholinesterase (AChE) inhibitors, However, it can be also applied in any other procedures related to bioactivity (e.g. 2,2-Diphenyl-1-picryl-hydrazyl-DPPH screen test for radicals). This system has been also used for determination of half maximal inhibitory concentration (IC50 values) of the active inhibitor-galanthamine, as an example. Moreover, AChE inhibitory potencies of some of purified plant extracts, never studied before, have been quantitatively measured. This is first report of usage such the 2D TLC/HPLC/MS system both for qualitative and quantitative evaluation of cholinesterase inhibitors in biological matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Effect of graphene layer thickness and mechanical compliance on interfacial heat flow and thermal conduction in solid-liquid phase change materials.

    Science.gov (United States)

    Warzoha, Ronald J; Fleischer, Amy S

    2014-08-13

    Solid-liquid phase change materials (PCMs) are attractive candidates for thermal energy storage and electronics cooling applications but have limited applicability in state-of-the-art technologies due to their low intrinsic thermal conductivities. Recent efforts to incorporate graphene and multilayer graphene into PCMs have led to the development of thermal energy storage materials with remarkable values of bulk thermal conductivity. However, the full potential of graphene as a filler material for the thermal enhancement of PCMs remains unrealized, largely due to an incomplete understanding of the physical mechanisms that govern thermal transport within graphene-based nanocomposites. In this work, we show that the number of graphene layers (n) within an individual graphene nanoparticle has a significant effect on the bulk thermal conductivity of an organic PCM. Results indicate that the bulk thermal conductivity of PCMs can be tuned by over an order of magnitude simply by adjusting the number of graphene layers (n) from n = 3 to 44. Using scanning electron microscopy in tandem with nanoscale analytical techniques, the physical mechanisms that govern heat flow within a graphene nanocomposite PCM are found to be nearly independent of the intrinsic thermal conductivity of the graphene nanoparticle itself and are instead found to be dependent on the mechanical compliance of the graphene nanoparticles. These findings are critical for the design and development of PCMs that are capable of cooling next-generation electronics and storing heat effectively in medium-to-large-scale energy systems, including solar-thermal power plants and building heating and cooling systems.

  10. Properties of heavily impurity-doped PbSnTe liquid-phase epitaxial layers grown by the temperature difference method under controlled Te vapor pressure

    Science.gov (United States)

    Yasuda, Arata; Takahashi, Yatsuhiro; Suto, Ken; Nishizawa, Jun-ichi

    2017-07-01

    We propose the use of heavily impurity-doped Pb1-xSnxTe/PbTe epitaxial layers grown via the temperature difference method under controlled vapor pressure (TDM-CVP) liquid-phase epitaxy (LPE) for the preparation of IV-VI compounds for mid- to far-infrared optical device applications. A flat surface morphology and the distribution of a constant Sn concentration for 0.05 ≤ x ≤ 0.33 were observed in the epitaxial layers using electron-probe microanalysis. The segregation coefficient of Sn in Pb1-xSnxTe grown via TDM-CVP LPE (Tg = 640 °C) was xSSn?xLSn = 0.28. The appearance of the Fermi level pinning and persistent photoconductivity effects in In-doped PbSnTe were also proposed; we estimated that the activation energies of these processes were 2.8 and 39.7 meV, respectively, based on the In-doped Pb1-xSnxTe carrier profile as a function of ambient temperature. In Hall mobility measurements, Sn was assumed to be a main scattering center in the Pb1-xSnxTe epitaxial crystals. The impurity effect was also observed in Pb1-xSnxTe epitaxial growth, similar to the effects observed for Tl-doped PbTe bulk crystals. We concluded that the heavily doped Pb1-xSnxTe crystals grown via TDM-CVP LPE can be used to fabricate high-performance mid- to far-infrared optical devices.

  11. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  12. Research of IGPC Control Strategy Based-on Hybrid Optimization for Power Station Boiler Superheated Steam Temperature

    Directory of Open Access Journals (Sweden)

    Benxian Xiao

    2014-01-01

    Full Text Available Implicit Generalized Predictive Control (IGPC algorithm can directly identify controller parameters without the need of solving Diophantine equation, thus can reduce the on-line algorithm computation time. In order to improve IGPC performance and extend its application, modified Particle Swarm Optimization (PSO algorithm is introduced into IGPC rolling horizon optimization, combined with general IGPC gradient optimization method under unconstrained condition, a new hybrid optimization method is obtained, this modified IGPC can be used to both of the non-constraint industry process control and the constraint industry process control. Aiming at the superheated steam temperature control of sub-critical 600MW boiler, a new cascade compound control strategy that combines an outer loop IGPC master adjuster and an inner loop PID auxiliary adjuster is adopted. Finally the simulation results have shown that the proposed method can constrain the control action, prevent dramatic change of the input signal, thus can achieve good static and dynamic performances.

  13. Influence of Superheated Steam Temperature Regulation Quality on Service Life of Boiler Steam Super-Heater Metal

    Directory of Open Access Journals (Sweden)

    G. T. Kulakov

    2009-01-01

    Full Text Available The paper investigates influence of change in quality of superheated steam temperature regulations on service life of super-heater metal. А dependence between metal service life and dispersion value for different steel grades has been determined in the paper. Numerical values pertaining to increase of super-heater metal service life in case of transferring from manual regulation to standard system of automatic regulation (SAR have been determined and in case of transferring from standard SAR to improved SAR. The analysis of tabular data and plotted dependencies makes it possible to conclude that any change in conditions of convection super-heater metal work due to better quality of the regulation leads to essential increase of time period which is left till the completion of the service life of a super-heater heating surface.

  14. Phase field simulation of kinetic superheating and melting of aluminum nanolayer irradiated by pico- and femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Seok Hwang, Yong [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States); Levitas, Valery I. [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2013-12-23

    Two melting mechanisms are reproduced and quantified for superheating and melting of Al nanolayer irradiated by pico- and femtosecond laser using the advanced phase-field approach coupled with mechanics and a two-temperature model. At heating rates Q≤79.04 K/ps induced by picosecond laser, two-sided barrierless surface melting forms two solid-melt interfaces, which meet near the center of a sample. The temperature for surface melting is a linear function, and for complete melting it is a cubic function, of logQ. At Q≥300 K/ps induced by femtosecond laser, barrierless and homogeneous melting (without nucleation) at the sample center occurs faster than due to interface propagation. Good agreement with experimental melting time was achieved in a range of 0.95≤Q≤1290 K/ps without fitting of material parameters.

  15. Application of thin-layer chromatography with fluorescence scanning densitometry for analysing saturates in heavy liquids derived from co-pyrolysis of biomass and plastics

    Energy Technology Data Exchange (ETDEWEB)

    Cebolla, V.L. [Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de Carboquimica, Zaragoza (Spain); Matt, M. [Institute of Chemistry and Chemical Technology, Krasnoyarsk (Russian Federation). Siberian Branch of Russian Academy of Sciences; Membrado, L. [Universite de Metz, Saint-Avold (FR). Laboratoire de Chimie et Applications] [and others

    2002-01-01

    Two alternative methods, based on Thin-Layer Chromatography (TLC) with Fluorescence Scanning Densitometry have been developed for characterization of heavy liquids from copyrolysis of different kinds of biomass and plastics in autoclaves under inert atmosphere. A conventional TLC system, which includes a vertical developing tank, and a High Performance TLC (HPTLC) system, with a horizontal developing chamber and the use of HPTLC plates, have been used. The analytical method involves in both cases the measurement of two chromatograms per sample: the first, on a silica gel berberine-impregnated plate, for detection of saturates using the phenomenon of berberine-induced fluorescence; and the second, on a silica gel plate, for detection of aromatic-polars and polars, by native fluorescence. Although the HPTLC system is more sensitive and faster, both techniques represent an improvement with regard to current methods for analyzing these kinds of products. However their application depends on the particular solubility of each sample and on its slope of the fluorescent response-sample load regression. (orig.)

  16. Large scale simulation of liquid water transport in a gas diffusion layer of polymer electrolyte membrane fuel cells using the lattice Boltzmann method

    Science.gov (United States)

    Sakaida, Satoshi; Tabe, Yutaka; Chikahisa, Takemi

    2017-09-01

    A method for the large-scale simulation with the lattice Boltzmann method (LBM) is proposed for liquid water movement in a gas diffusion layer (GDL) of polymer electrolyte membrane fuel cells. The LBM is able to analyze two-phase flows in complex structures, however the simulation domain is limited due to heavy computational loads. This study investigates a variety means to reduce computational loads and increase the simulation areas. One is applying an LBM treating two-phases as having the same density, together with keeping numerical stability with large time steps. The applicability of this approach is confirmed by comparing the results with rigorous simulations using actual density. The second is establishing the maximum limit of the Capillary number that maintains flow patterns similar to the precise simulation; this is attempted as the computational load is inversely proportional to the Capillary number. The results show that the Capillary number can be increased to 3.0 × 10-3, where the actual operation corresponds to Ca = 10-5∼10-8. The limit is also investigated experimentally using an enlarged scale model satisfying similarity conditions for the flow. Finally, a demonstration is made of the effects of pore uniformity in GDL as an example of a large-scale simulation covering a channel.

  17. Quantitative determination of triterpenes from Amphiptherygium adstringens by liquid chromatography and thin-layer chromatography and morphological analysis of cuachalalate preparations.

    Science.gov (United States)

    Navarrete, Andres; Avula, Bharathi; Joshi, Vaishali C; Ji, Xiuhong; Hersh, Paul; Khan, Ikhlas A

    2006-01-01

    Amphiptherygium adstringens (Anacardiaceae/Julianaceae), local name "cuachalalate," is used in folk medicine for the treatment of cholelithiasis, fevers, fresh wounds, hypercholesterolemia, gastritis, gastric ulcers, and cancer of the gastrointestinal tract. The development of column high-performance liquid chromatography-photodiode array detector (LC-PDA) and high-performance thin-layer chromatography (HPTLC)-densitometry methods for the determination of masticadienonic acid and 3-hydroxymasticadienonic acid in cuachalalate preparations is described in this paper. Good separation of the compounds could be achieved by both methods. Either might be preparable depending on the requirements. The LC separation was performed on a Phenomenex Synergi MAX-RP 80A reversed-phase column operated at 40 degrees C with detection at 215 nm. The plant materials were extracted with methanol by sonication. The triterpenes present in the plant material and commercial extracts were separated with an acetonitrile-water reagent alcohol isocratic system. The limit of detection was 0.1-0.2 microg/mL. The relative standard deviation values for the determination of triterpenes in plant extracts were less than 1.00%. This is the first report of an analytical method developed for the quantitative analysis of triterpenes from Amphiptherygium adstringens by LC-PDA and HPTLC. The stem bark showed higher amounts of triterpenes, and low amounts in root and stem root. The microscopic description of the crude drug of cuachalalate was also provided.

  18. Determination of guanine and adenine by high-performance liquid chromatography with a self-fabricated wall-jet/thin-layer electrochemical detector at a glassy carbon electrode.

    Science.gov (United States)

    Zhou, Yaping; Yan, Hongling; Xie, Qingji; Yao, Shouzhuo

    2015-03-01

    A sensitive wall-jet/thin-layer amperometric electrochemical detector (ECD) coupled to high-performance liquid chromatography (HPLC) was developed for simultaneous determination of guanine (G) and adenine (A). The analytes were detected at a glassy carbon electrode (GCE) and the HPLC-ECD calibration curves showed good linearity (R(2)>0.997) under optimized conditions. Limits of detection for G and A are 0.6 nM and 1.4 nM (S/N=3), respectively, which are lower than those obtained with an UV-vis detector and a commercial electrochemical detector. We have successfully applied this HPLC-ECD to assess the contents of G and A in hydrochloric acid-digested calf thymus double-stranded DNA. In addition, we compared in detail the analysis of G and A by cyclic voltammetry (CV) and by the HPLC-ECD system on both bare GCE and electroreduced graphene oxide (ERGO) modified GCE. We found that the adsorption of G and A on the electrode surfaces can vary their anodic CV peaks and the competitive adsorption of G and A on the limited sites of the electrode surfaces can cause crosstalk effects on their anodic CV peak signals, but the HPLC-ECD system is insensitive to such electrode-adsorption and can give more reliable analytical results. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations

    Directory of Open Access Journals (Sweden)

    Ming Chen

    2017-02-01

    Full Text Available Room-temperature ionic liquids (RTILs are an emerging class of electrolytes for supercapacitors. In this work, we investigate the effects of different supercapacitor models and anion shape on the electrical double layers (EDLs of two different RTILs: 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonylimide ([Emim][Tf2N] and 1-ethyl-3-methylimidazolium 2-(cyanopyrrolide ([Emim][CNPyr] by molecular dynamics (MD simulation. The EDL microstructure is represented by number densities of cations and anions, and the potential drop near neutral and charged electrodes reveal that the supercapacitor model with a single electrode has the same EDL structure as the model with two opposite electrodes. Nevertheless, the employment of the one-electrode model without tuning the bulk density of RTILs is more time-saving in contrast to the two-electrode one. With the one-electrode model, our simulation demonstrated that the shapes of anions significantly imposed effects on the microstructure of EDLs. The EDL differential capacitance vs. potential (C-V curves of [Emim][CNPyr] electrolyte exhibit higher differential capacitance at positive potentials. The modeling study provides microscopic insight into the EDLs structure of RTILs with different anion shapes.

  20. Atomic layer deposition of indium oxide thin film from a liquid indium complex containing 1-dimethylamino-2-methyl-2-propoxy ligands

    Science.gov (United States)

    Han, Jeong Hwan; Jung, Eun Ae; Kim, Hyo Yeon; Kim, Da Hye; Park, Bo Keun; Park, Jin-Seong; Son, Seung Uk; Chung, Taek-Mo

    2016-10-01

    In2O3 thin films were grown from a newly developed, liquid, homoleptic, In-based complex, tris(1-dimethylamino-2-methyl-2-propoxy)indium [In(dmamp)3], and O3 by atomic layer deposition (ALD) at growth temperatures of 150-200 °C. In(dmamp)3 exhibited single-step evaporation with negligible residue and excellent thermal stability between 30 and 250 °C. The self-limiting surface reaction of In2O3 during ALD was demonstrated by varying the In(dmamp)3 and O3 pulse lengths, with a growth rate of 0.027 nm/cycle achieved at 200 °C. The In2O3 films grown at temperatures over 175 °C exhibited negligible concentrations of impurities, whereas that grown below 175 °C had concentrations of residual C of 6-8 at.%. Glancing angle X-ray diffraction revealed that the In2O3 films were polycrystalline in nature when the deposition temperature was greater than 200 °C. The In2O3 films grown at 150-200 °C exhibited carrier concentrations of 1.5 × 1018-6.6 × 1019 cm-3, resistivities of 15.1-2 × 10-3 Ω cm, and Hall mobilities of 0.8-42 cm2/(V s).

  1. Research on steam-supply performance of ship micro-superheated steam generating system%船舶微过热蒸汽发生系统供汽性能研究

    Institute of Scientific and Technical Information of China (English)

    杨元龙

    2016-01-01

    In order to improve ship micro-superheated steam generating system stability and optimize its performance parameters, the micro-superheated steam generating system steam-supply response characteristic under the steady and transient state will be cleared. The ship micro-superheated steam generating system was taken as the mechanism model herein. The steady characteristics of velocity pressure, and temperature field for micro-superheated steam generating system were calculated by method of CFD simulation. The boundary conditions were introduced to treat as actual operating parameters of this system. The dynamic simulation study on micro-superheated steam generating system steam-supply response characteristic was carried out. The key parameters distributions of saturated and superheated steam mixing massflow, micro-superheated steam pressure and temperature were obtained. Meanwhile, the micro-superheated steam mixing factor was proposed, which could express quantificationally micro-superheated steam generating system mixing characteristics and effects of micro-superheated steam temperature. The calculated results showed that the pressure drop of saturated steam was higher than one of superheated steam. The micro-superheated steam pressure reduced gradually, leading to larger saturated and superheated steam massflow. These caused micro-superheated steam mixing factor to reduce, which resulted in that the micro-superheated steam temperature reduced slightly. Based on the analysis of the micro-superheated steam generating system steam-supply performance parameters, it could satisfy demand for equipment performance. These could be used to design ship steam power system.%为提高船舶微过热蒸汽发生系统的稳定性和优化微过热系统性能参数,探析稳态、动态工况下微过热蒸汽发生系统供汽响应特性。本文以船舶微过热蒸汽发生系统为机理模型,采用 CFD模拟方法计算了微过热蒸汽发生系统速度场、压

  2. Preparation of manganese oxide immobilized on SBA-15 by atomic layer deposition as an efficient and reusable catalyst for selective oxidation of benzyl alcohol in the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Mahdavi, Vahid, E-mail: v-mahdavi@araku.ac.ir; Mardani, Mahdieh

    2015-04-01

    Manganese oxide supported on mesoporous silica SBA-15 catalyst (Mn-SBA-15) was tested with Mn contents in the range of 0.8–23 wt%. Samples were prepared by the controlled grafting process of atomic layer deposition (ALD). Other sample was prepared for comparisons by the wet impregnation method. These samples were characterized by the techniques of ICP, XRD, SEM, Raman, FT-IR spectroscopy, diffuse reflectance UV–Vis, TGA-DSC, and N{sub 2} absorption–desorption surface area measurement. Results indicated that anchored manganese oxide particles have been successfully synthesized over the surface of SBA-15. These samples contained Red-Ox ion pairs of Mn{sup 2+} and Mn{sup 3+} highly dispersed on the mesoporous silica surface. The impregnated sample exhibited lower surface area and contained Red-Ox ion pairs of Mn{sup 3+} and Mn{sup 4+} more aggregated particles on the SBA-15 surface. Results determined Mn-SBA-15 as an efficient and selective catalyst for oxidation of benzyl alcohol with tert-butylhydroperoxide in liquid phase. In accordance with expectations, there was a negligible amount of leaching of immobilized manganese oxide from the support during the reaction, because of strong surface interaction between manganese oxide and hydroxyls groups. The influences of reaction temperature, reaction time, solvent, TBHP/benzyl alcohol molar ratio, amount of catalyst and reusability were investigated. Under optimized conditions (0.2 g catalyst, TBHP/benzyl alcohol molar ratio 1, solvent acetonitrile; T = 90 °C; reaction time 8 h), results achieved 70% conversion of benzyl alcohol and 100% selectivity to benzaldehyde. - Highlights: • Manganese oxide immobilized on SBA-15 were prepared by atomic layer deposition (ALD). • Oxidation of benzyl alcohol to benzaldehyde over this catalyst were investigated. • Effects of loading of manganese oxide, T, oxidant/alcohol ratio were investigated. • The leaching of manganese oxide from support during the reaction was

  3. 双向薄层色谱法分析混合糖组分%Two-step thin layer chromatography for saccharides analysis of mixed saccharides liquid

    Institute of Scientific and Technical Information of China (English)

    刘秀花; 崔孟岐; 王莉; 张淑红; 宋兆齐; 梁峰

    2015-01-01

    薄层色谱法分析糖类混合物的组分简便快速,但是并不能将甘露糖、阿拉伯糖、半乳糖、木糖、葡萄糖进行彻底分离。本文采用双向层析的方法分别以V乙腈∶V水=85∶15为第一向展层剂,以V正丁醇∶V乙酸乙酯∶V水=7∶2∶1为第二向展层剂优化层析。结果显示,得到了较好的分离效果,可以定性检测出糖类组分。对比国内外研究,此方法简单,因此双向薄层色谱法可以作为一种简单、准确、清晰、便利的方法定性检测糖类混合物的组分。%The thin layer chromatography ( TLC) analysis of the mixed saccharides liquid composition effect is good , simple and rapid , but it doesn′t put the mannose , arabinose , galactose , xylose , glucose separately .This paper using the two step-TLC, the first step by Vacetonitrile∶Vwater =85∶15,and the second step by Vn-butanol∶V ethyl acetate∶V Water =7∶2∶1 as developing solvent for optimization of chromatography .Results show that using the above method to analyze saccharides mixture , got the good separation effect , can the qualitative detection of saccharides components , comparative research both at home and abroad , the use effect of the method is very simple and intuitive.Therefore, the two step thin layer chromatography ( TLC) can be used as a simple , accurate, clear and convenient method of qualitative detection of saccharide mixture components .

  4. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed.

    Science.gov (United States)

    Kamal, Abid; Khan, Washim; Ahmad, Sayeed; Ahmad, F J; Saleem, Kishwar

    2015-01-01

    The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC) methods for the development of quantification of khellin present in the seeds of Ammi visnaga. RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v) as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v) as a mobile phase. The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem), robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10-80 μg/mL in HPLC and 25-1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63-1.97%, 0.62-2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient.

  5. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed

    Directory of Open Access Journals (Sweden)

    Abid Kamal

    2015-01-01

    Full Text Available Objective: The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC methods for the development of quantification of khellin present in the seeds of Ammi visnaga. Materials and Methods: RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v as a mobile phase. Results: The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem, robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10–80 μg/mL in HPLC and 25–1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63–1.97%, 0.62–2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. Conclusions: The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient.

  6. Vortex-Induced Vapor Explosion during Drop Impact on a Superheated Pool

    KAUST Repository

    Alchalabi, M.A.

    2017-04-18

    Ultra high-speed imaging is used to investigate the vapor explosion when a drop impacts onto a high-temperature pool. The two liquids are immiscible, a low boiling-temperature perfluorohexane drop, at room temperature, which impacts a high boiling-temperature soybean-oil pool, which is heated well above the boiling temperature of the drop. We observe different regimes: weak and strong nucleate boiling, film boiling or Leidenfrost regime and entrainment followed by vapor explosion. The vapor explosions were seen to depend on the formation of a rotational flow at the edge of the impact crater, near the pool surface, which resembles a vortex ring. This rotational motion entrains a thin sheet of the drop liquid, to become surrounded by the oil. In that region, the vapor explosion starts at a point after which it propagates azimuthally along the entire periphery at high speed.

  7. Modeling of an once through helical coil steam generator of a superheated cycle for sizing analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Sik; Sim, Yoon Sub; Kim, Eui Kwang [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    A thermal sizing code, named as HSGSA (Helical coil Steam Generator Sizing Analyzer), for a sodium heated helical coil steam generator is developed for KALIMER (Korea Advanced LIquid MEtal Reactor) design. The theoretical modeling of the shell and tube sides is described and relevant correlations are presented. For assessment of HSGSA, a reference plant design case is compared to the calculational outputs from HSGSA simulation. 9 refs., 6 figs. (Author)

  8. Laser ablation of absorbing liquids under transparent cover: acoustical and optical monitoring

    Science.gov (United States)

    Samokhin, A. A.; Il'ichev, N. N.; Pivovarov, P. A.; Sidorin, A. V.

    2016-06-01

    Phase transition induced with infrared (λ = 2920 nm and λ = 2940 nm) nanosecond laser pulses in strongly absorbing liquids (water, ethanol) under transparent solid cover is investigated with the help of acoustical and optical monitoring. LiNbO3 transducer is used for registration of pressure pulses generated in irradiated liquids. Optical signals due to scattering and specular reflection of probing optical beams are explored with the schemes involving total internal reflection and interference effects. Combination of these two optical diagnostic methods permits for the first time to show that irradiation of covered liquids leads to vapor cavity formation which is divided from the cover with thin (submicron) liquid film despite the fact that radiation intensity maximum is located just at the liquid-plate boundary. The cavity formation is due to explosive boiling which occurs when the superheated liquid reaches its superheating limit in near critical region. After the first acoustical signal, the second signal is observed with several hundreds microseconds time delay which is caused by the vapor cavity collapse. Some results of optical and acoustical diagnostics in the case of free liquid surface are also presented.

  9. Superheating and melting within aluminum core-oxide shell nanoparticles for a broad range of heating rates: multiphysics phase field modeling.

    Science.gov (United States)

    Hwang, Yong Seok; Levitas, Valery I

    2016-10-19

    The external surface of metallic particles is usually covered by a thin and strong oxide shell, which significantly affects superheating and melting of particles. The effects of geometric parameters and heating rate on characteristic melting and superheating temperatures and melting behavior of aluminum nanoparticles covered by an oxide shell were studied numerically. For this purpose, the multiphysics model that includes the phase field model for surface melting, a dynamic equation of motion, a mechanical model for stress and strain simulations, interface and surface stresses, and the thermal conduction model including thermoelastic and thermo-phase transformation coupling as well as transformation dissipation rate was formulated. Several nontrivial phenomena were revealed. In comparison with a bare particle, the pressure generated in a core due to different thermal expansions of the core and shell and transformation volumetric expansion during melting, increases melting temperatures with the Clausius-Clapeyron factor of 60 K GPa(-1). For the heating rates Q ≤ 10(9) K s(-1), melting temperatures (surface and bulk start and finish melting temperatures, and maximum superheating temperature) are independent of Q. For Q ≥ 10(12) K s(-1), increasing Q generally increases melting temperatures and temperature for the shell fracture. Unconventional effects start for Q ≥ 10(12) K s(-1) due to kinetic superheating combined with heterogeneous melting and geometry. The obtained results are applied to shed light on the initial stage of the melt-dispersion-mechanism of the reaction of Al nanoparticles. Various physical phenomena that promote or suppress melting and affect melting temperatures and temperature of the shell fracture for different heating-rate ranges are summarized in the corresponding schemes.

  10. Liquid Crystals

    Science.gov (United States)

    1990-01-01

    Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

  11. A universal bubble-growth equation for pure liquids and binary solutions with a non-volatile solute

    Energy Technology Data Exchange (ETDEWEB)

    Miyatake, Osamu [Kyushu Univ., Fukuoka (Japan). Dept. of Chemical Engineering; Tanaka, Itsuo [Gifu Univ. (Japan). Dept. of Biological Production System; Lior, N. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Mechanical Engineering and Applied Mechanics

    1996-12-31

    A simple equation suitable for predicting the growth rate of a vapor bubble in uniformly-superheated pure liquids and in binary solutions with a non-volatile solute was developed. The equation also improves on the popular pure-liquid bubble growth expression of Mikie et al. (1970) in that it is valid throughout the bubble growth history, i.e., in the surface-tension-, inertia-, and heat-transfer-controlled regimes, it accounts for bubble growth acceleration effects, and uses correctly-related and variable fluid properties. It was found to agree very well with experimental data for pure water and for aqueous NaCl solutions. As the bubble growth in superheated solutions with a non-volatile solute was found to be quite insensitive to diffusion and non-equilibrium effects in a broad range of common solution properties, this equation is likely to be universally valid for many liquids and solutions. Bubble growth in superheated fluids is of key interest in boiling phenomena in general and in flash evaporation in particular. Applications include a wide variety of separation processes such as water desalination, and energy conversion processes such as ocean-thermal energy conversion, geothermal power generation, and nuclear reactor safety.

  12. Influence of the type of working fluid in the lower cycle and superheated steam parameters in the upper cycle on effectiveness of operation of binary power plant

    Directory of Open Access Journals (Sweden)

    Stachel Aleksander A.

    2015-03-01

    Full Text Available In the paper presented have been the results of the analysis of effectiveness of operation of binary power plant consisting of combined two Clausius-Rankine cycles, namely the binary cycle with water as a working fluid in the upper cycle and organic substance as a working fluid in the lower cycle, as well as a single fluid component power plant operating also in line with the C-R cycle for superheated steam, with water as a working fluid. The influence of the parameters of superheated steam in the upper cycle has been assessed as well as the type of working fluid in the lower cycle. The results of calculations have been referred to the single-cycle classical steam power plant operating at the same parameters of superheated steam and the same mass flow rate of water circulating in both cycles. On the basis of accomplished analysis it has been shown that the binary power plant shows a greater power with respect to the reference power plant.

  13. Thermal Velocities Arising from Injection in 2-Phase and Superheated Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Shook, George Michael

    2001-01-01

    Production from and injection into geothermal reservoirs gives rise to temperature fronts that move through the porous medium. As many as two temperature fronts are observed in 1-D simulations. The first front is related to the saturation temperature of the production pressure. Its velocity can be calculated from the amount of excess heat in the reservoir, defined as the amount of energy above the interface temperature, Ti = Tsat(Pwf). The second temperature front velocity is the same as for single phase liquid conditions.

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

    Science.gov (United States)

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

    2016-05-01

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

  15. Simulation and Experimental Determination of Technological Liquid Molding Parameters of Tubing Basalt Insulation

    Directory of Open Access Journals (Sweden)

    Yu. V. Badanina

    2015-01-01

    Full Text Available The article is dedicated to one of the most important and urgent tasks in mechanical engineering development - the creation of low-density and environmentally-friendly thermoinsulation from available cheap basalt fibers for products to operate at temperatures up to 700°C.One of the most effective applications of such thermo-insulation is to develop and provide highly porous coatings from short basalt fibers by liquid filtration for tubing (T to supply superheated up to 420° C steam under pressure of 35 MPa in the deep layers with severe highviscosity oil. Tubing with the short low-density basalt insulation can be used for a greater depth than the vacuum-insulated tubing, which are also called "thermo-cases", and do not fully meet business needs for long-term reliability of oil vacuum tubes, too large mass per unit length of their design and, as a consequence, the impossibility to use such pipes for deep wells.The aim of the work is to simulate a liquid filtration process of short fibers and determine technological parameters of producing thermal insulation coatings of tubing pipes from basalt fibers and mineral binder shaped as cylinders and cylindrical shells. The paper proposes a mathematical model of free filtration deposition of short fibers from liquid slurry, which describes dynamics of creating thermal insulation products and allows us to determine the rational parameters of their manufacturing process. It shows methods to improve the products quality while forming the thermal insulation by filtration through additional vacuum deposition of a filtrate chamber and the final prepressing of sediment layer, giving dimensions and shape to the final product.The paper defines a prescription hydro mass composition. It shows that to increase the compressive strength of highly fibrous rings and cylindrical shells it is necessary to use based on oxide А12O3 5-7% by weight mineral binder, which fixes basalt fibers in places of their contacts. It

  16. Process analysis of superheated steam pre-treatment of wheat straw and its relative effect on ethanol selling price

    Directory of Open Access Journals (Sweden)

    Dave Barchyn

    2014-12-01

    Full Text Available Existing bioethanol operations rely on starch-based substrates, which have been criticized for their need to displace food crops in order to be produced. As an alternative to these first generation biofuels, the use of agricultural residues is being considered to create more environmentally-benign second generation, or cellulosic biofuels. Recalcitrance of these substrates to fermentation requires extensive pre-treatment processes, which often consume more energy than can be extracted from the ethanol that they produce, so one of the priorities in developing cellulosic ethanol is an effective and efficient pre-treatment method. This study examines the use of superheated steam (SS as a process medium by which wheat straw lignocellulosic material is pre-treated. Following enzymatic hydrolysis, it was found that 47% of the total glucose could be liberated from the substrate, and the optimal conditions for pre-treatment were 15 min in hot water (193 kPa, 119˚C followed by 2 min in SS. Furthermore, a preliminary relative economic analysis showed that the minimum ethanol selling price (MESP was comparable to that obtained from steam explosion, a similar process, while energy consumption was 22% less. The conclusion of the study is that SS treatment stands to be a competitive pre-treatment technology to steam explosion.

  17. 液层厚度比对环形腔内双层液体的热毛细对流稳定性的影响%Influence of liquid layer depth ratio on stability of thermocapillary flow in annular two-layer system with upper rigid wall

    Institute of Scientific and Technical Information of China (English)

    莫东鸣

    2015-01-01

    In order to understand the liquid layer depth ratio on the stability of two-layer system with upper rigid walls at the microgravity condition,a linear stability analysis of thermocapillary flow in the annular immiscible two-layer system of 5cSt silicone oil and HT-70 was carried out using Implicity Restarted Arnoldi Method (IRAM).Critical values of Marangoni number,wave number and phase velocity were obtained at different liquid layer depth ratios,different aspect ratios of the cavity and different radius rations.The thermofluid wave pattern at the liquid-liquid interface near the critical Marangoni number was also exhibited.%为了了解微重力条件下、水平温度梯度作用时,上部为固壁的环形腔内双层流体系统中液层厚度比对流动稳定性的影响,采用隐式重启 Arnoldi方法(IRAM)对环形池内5cSt 硅油/HT-70双层流体的热对流过程进行了线性稳定性分析,获得了不同液层厚度比下系统流动的临界 Marangoni 数、临界波数、临界相速度,并通过计算特征向量,得到了临界 Marangoni数附近液-液界面的热流体波形态。

  18. A Neutron-Diffraction Study of the Solid Layers at the Liquid Solid Boundary in 4He-Films Adsorbed on Graphite

    DEFF Research Database (Denmark)

    da Costa Carneiro, Kim; Passell, L.; Thomlinson, W.

    1981-01-01

    A neutron scattering study of the structure of 4He films adsorbed on graphite is reported. Diffraction from helium monolayers at a temperature of 1.2K shows the formation of an incommensurate, triangular-lattice solid of high density. As the coverage is increased above two layers, the diffraction...... pattern changes indicating solidification of a second layer. The observed two-layer patterns can be indexed with either a pair of incommensurate, triangular-lattice solid layers of different densities or a close-packed bilayer; the experimental information available is not sufficient to make a more...... precise identification. A measurement of the height of the first helium layer above the graphite basal plane was also made. This was done by determining the coverage-dependent shift in the position of the graphite (002) diffraction peak (assumed to arise from interference between film and substrate...

  19. 污泥过热蒸汽干燥工艺优化%Process parameters optimization of superheated steam drying for sludge

    Institute of Scientific and Technical Information of China (English)

    张绪坤; 温祥东; 罗俊; 吴起; 徐刚; 徐建国

    2015-01-01

    The sludge is known as the byproduct generated in the process of pollution control. It is featured by the high moisture content, complicated components and massive deadly microorganism, thus easily leading to secondary pollution. The dehydration is a necessary process to realize the sludge harmless reduce the sludge amount and improve the resource utilization. The thermal drying is a feasible method to reduce the moisture content. The process of hot air drying will cause a large amount of harmful exhaust gas, adding to the difficulty and cost of controlling exhaust gas. The sludge drying, which uses superheated steam as the drying medium, will further lower the risk of explosion and reduce the harmful gas account due to the absence of oxygen in the drying medium. However, the superheated steam drying of sludge is also faced with the problems such as energy consumption and long drying time. Hence, it has become a major task to dry the sludge in an economic and effective manner. The purpose of this research is to determine the technological parameters for optimal sludge superheated steam drying. Besides building the experimental device for superheated steam drying under atmospheric pressure and choosing the relative unit energy consumption and the average drying strength as the evaluation indices, this paper has also designed the experiment of three-factor quadratic orthogonal rotation combination. A mathematical model is also built, which adopts the technological parameters for sludge superheated steam drying including superheated steam temperature sludge quality and superheated steam flow. In addition, this paper has employed the single-factor and two-factor method to analyze the relationship between various factors and evaluation indices. According to the analysis on experimental data, the established regression equation of establishing is significant, and the coefficient of determination on the relative unit energy consumption and the average drying strength were

  20. Amorphous-crystalline dual-layer structures resulting from metastable liquid phase separation in (Fe50Co25B15Si10)8oCu20 melt-spun ribbons

    Institute of Scientific and Technical Information of China (English)

    Cao Chong-De; Gong Su-Lian; Guo Jin-Bo; Song Rui-Bo; Sun Zhan-Bo; Yang Sen; Wang Wei-Min

    2012-01-01

    (Fe50Co25B15Si10)80Cu20 ribbons are prepared by using the single-roller melt-spinning method.A dual-layer structure consisting of a (Fe,Co)-rich amorphous phase and a Cu-rich crystalline phase forms due to metastable liquid phase separation before solidification.The magnetic hysteresis loops of the as-quenched and annealed samples are measured at room temperature.It is indicated that the coercivity of the ribbon is almost zero in the as-quenched state.The crystallization leads to the increase of coercivity and decrease of saturation magnetization.

  1. Transcriptional response of selected genes of Salmonella enterica serovar Typhimurium biofilm cells during inactivation by superheated steam.

    Science.gov (United States)

    Ban, Ga-Hee; Kang, Dong-Hyun; Yoon, Hyunjin

    2015-01-02

    Superheated steam (SHS), produced by the addition of heat to saturated steam (SS) at the same pressure, has great advantages over conventional heat sterilization due to its high temperature and accelerated drying rate. We previously demonstrated that treatment with SHS at 200°C for 10 sec inactivated Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilm cells on the surface of stainless steel to below the detection limit. However, bacteria withstanding heat stress become more resistant to other stress conditions, and may be more virulent when consumed by a host. Herein, we studied the transcriptional regulation of genes important for stress resistance and virulence in Salmonella biofilms after SHS treatments. Genes encoding heat shock proteins and general stress resistance proteins showed transcriptional surges after 1 sec of SHS treatment at 200°C, with parallel induction of stress-related regulator genes including rpoE, rpoS, and rpoH. Interestingly, Salmonella biofilm cells exposed to SHS showed decreased transcription of flagella and Salmonella pathogenicity island-1 (SPI-1) genes required for motility and invasion of host cells, respectively, whereas increased transcription of SPI-2 genes, important for bacterial survival and replication inside host cells, was detected. When the transcriptional response was compared between cells treated with SHS (200°C) and SS (100°C), SHS caused immediate changes in gene expression by shorter treatments. Understanding the status of Salmonella virulence and stress resistance induced by SHS treatments is important for wider application of SHS in controlling Salmonella biofilm formation during food production.

  2. The role of superheating in the formation of Glass Mountain obsidians (Long Valley, CA) inferred through crystallization of sanidine

    Science.gov (United States)

    Waters, Laura E.; Andrews, Benjamin J.

    2016-10-01

    Mountain obsidians were superheated prior to crystallization.

  3. Deposition of a thin film of TiOx from a titanium metal target as novel blocking layers at conducting glass/TiO2 interfaces in ionic liquid mesoscopic TiO2 dye-sensitized solar cells.

    Science.gov (United States)

    Xia, Jiangbin; Masaki, Naruhiko; Jiang, Kejian; Yanagida, Shozo

    2006-12-21

    In dye-sensitized TiO2 solar cells, charge recombination processes at interfaces between fluorine-doped tin oxide (FTO), TiO2, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. From this point of view, a high work function material such as titanium deposited by sputtering on FTO has been investigated as an effective blocking layer for preventing electron leakage from FTO without influencing electron injection. X-ray photoelectron spectroscopy analysis indicates that different species of Ti (Ti4+, Ti3+, Ti2+, and a small amount of Ti0) exist on FTO. Electrochemical and photoelectrochemical measurements reveal that thin films of titanium species, expressed as TiOx, work as a compact blocking layer between FTO and TiO2 nanocrystaline film, improving Voc and the fill factor, finally giving a better conversion efficiency for dye-sensitized TiO2 solar cells with ionic liquid electrolytes.

  4. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  5. Drying of foodstuffs by low-pressure superheated steam%食品低压过热蒸汽干燥技甫

    Institute of Scientific and Technical Information of China (English)

    马怡光; 张绪坤; 佘蓉; 魏伟

    2012-01-01

    Superheated steam drying is a new technology developed recently, compared with conventional hot air drying, it has some advantages, such as high drying efficiency, low energy consumption, better products' quality and so on. Drying of foodstuffs with superheated steam features advantages in comparison with traditional hot air drying are absence of oxygen prevents oxidative reactions, rendering a very porous material, easily rehydrated and with a minimum of volume reduction in most cases. Especially, drying of foodstuffs with low-pressure superheated which avoid the disadvantages of products qualities dried use atmospheric pressure or higher, it will be widely developed in the future.%过热蒸汽干燥是近年来发展起来的新技术,和传统的热风对流干燥相比具有干燥效率高、能耗低和干燥产品质量好等优点。过热蒸汽应用于食品的干燥,其显著的特点是能实现无氧或少氧的干燥环境,干燥过程不会出现“硬壳”或“结皮”的现象,消除了进一步干燥可能出现的障碍,产品具有多孔的结构。特别是低压过热蒸汽干燥应用于食品等热敏性物料,避免了过热蒸汽干燥操作温度高,从而影响产品质量的问题,具有广阔的发展前景。

  6. Network-based reliability control for superheated steam temperature%基于网络的过热蒸汽温度可靠性控制

    Institute of Scientific and Technical Information of China (English)

    顾伟; 庄宝春; 刘金良

    2014-01-01

    This paper investigates the problem of reliability control for network-based superheated steam temperature control system , taking into account the actuator failure and transmition of the control signal of superheated steam through network .An integrated model for stochastic actuator failure was established , which takes the cascade con-trol as the basic control strategy .By using Lyapunov stability theory and linear matrix inequities ( LMIs) technolo-gy, the randomly and equally divided stability conditions for the system are given , and then the controller design method for superheated steam temperature control system which takes actuator stochastic fault into account was put forward.At last, an application example is provided to demonstrate the effectiveness of the proposed method .%研究了在考虑执行器故障情况下,以及过热汽温的控制信号通过网络进行传输的情况下,过热汽温的温度控制系统的可靠性控制问题。建立了执行器随机故障模型,以串级控制为基本控制策略,利用Lyapunov 稳定性理论和线性矩阵不等式( linear matrix inequities , LMIs)技术,给出了系统随机均分稳定条件,提出了考虑执行器具有随机故障的过热蒸汽控制系统的控制器设计方法。通过仿真实验证明了提出的控制器设计方案的有效性。

  7. 过热蒸汽膨化干燥番茄及其理化品质%Physicochemical characteristics of superheated steam puffing dried tomato

    Institute of Scientific and Technical Information of China (English)

    徐将; 安凤平; 赖彩如; 仇东朝; 宋洪波

    2013-01-01

    利用过热蒸汽膨化干燥技术,对热风干燥与过热蒸汽膨化干燥的干燥特性、处理前后番茄的理化品质进行比较和分析,结果表明:番茄经过热蒸汽膨化后干燥,干燥速度快,比单纯采用热风干燥所需的干燥时间缩短34.4%;过热蒸汽膨化干燥的番茄体积饱满,色泽较好,营养保存率高,微观组织呈现明显的蜂窝状结构,复水比高,复水温度较高时的复水比明显高于热风干燥的番茄;过热蒸汽膨化干燥的番茄在85℃的水中复水6 min,其硬度和粘性适中,弹性和咀嚼性值最大,感官评价最好.%superheated steam puffing drying technique was used to process tomato, the drying property between hot air dried tomato and superheated steam puffing dried tomato was compared, the physicochemical characteristics of tomato before and after the treatment of superheated steam puffing drying were also compared. The results showed that tomato after the treatment of superheated steam puffing drying had full volume bulk, better color and high nutrients preserving rate; the porous microstructure was significantly enlarged; the drying velocity was speeded up, the drying time was curtailed 34.4% than hot air drying. Meanwhile, the puffing dried tomato also had higher rehydration rate. After 6 min rehydration at the temperature of 85 ℃, the tomato had moderate hardness and mucosity, maximal elasticity and chewiness, as well as the highest sensory evaluation score. Temperature of 85 ℃, time of 6 min was chosen to be rehydration condition.

  8. Harvesting contaminants from liquid

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Hunter, Scott R.

    2016-05-31

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

  9. The Analysis on Advantages of Superheated Steam Stimulation Technology in Thin Heavy Oil Reservoir%薄层稠油油藏过热蒸汽吞吐技术优势解析

    Institute of Scientific and Technical Information of China (English)

    崔连训; 庞占喜; 李媛媛; 路涛

    2012-01-01

    在过热蒸汽开发稠油油藏提高采收率机理分析基础上,利用数值模拟技术对1-3 m、3-5 m和5 m以上薄层稠油油藏实施过热蒸汽吞吐的开发效果进行了对比和分析.通过对比普通湿蒸汽、高温湿蒸汽和过热蒸汽的增油能力、节约蒸汽效果及油藏特征,分析了稠油油藏过热蒸汽吞吐的技术优势.研究结果表明,过热蒸汽吞吐的增油能力明显高于普通湿饱和蒸汽吞吐和高温湿蒸汽,但当过热度超过20℃后,增油幅度变缓;相同产油量时,过热蒸汽要比湿饱和蒸汽节约大量蒸汽.这是因为过热蒸汽携热量大,比容高,可以有效萃取稠油中的轻质组分,有效扩大波及体积,增加洗油效率.%Base on the mechanisms of superheated steam enhancing oil recovery in heavy oil reservoirs, numerical simulation was employed to analyze development effectiveness of superheated steam stimulation in thin heavy oil reservoirs with different net pay, such as 1-3 m, 3-5 m and over 5 m. By contrasting of incremental oil effect, steam-saving volume, reservoir features among conventional saturated steam, hot saturated steam and superheated steam, the technological advantages of superheated steam stimulation was analyzed to develop heavy oil reservoirs. The results show that incremental oil effect of superheated steam is much higher than conventional saturated steam and hot saturated steam, but it gradually increases slower when degree of superheat was over 20 ℃. When the same volume of heavy oil was produced by the three kinds of steams, superheated steam could save amount of steam. This is because that superheated steam has higher heat quantity and larger specific volume. Superheated steam can effectively extract light component in heavy oil, increase swept volume and enhance washing oil efficiency in heavy oil reservoirs.

  10. Frontally eluted components procedure with thin layer chromatography as a mode of sample preparation for high performance liquid chromatography quantitation of acetaminophen in biological matrix.

    Science.gov (United States)

    Klimek-Turek, A; Sikora, M; Rybicki, M; Dzido, T H

    2016-03-04

    A new concept of using thin-layer chromatography to sample preparation for the quantitative determination of solute/s followed by instrumental techniques is presented Thin-layer chromatography (TLC) is used to completely separate acetaminophen and its internal standard from other components (matrix) and to form a single spot/zone containing them at the solvent front position (after the final stage of the thin-layer chromatogram development). The location of the analytes and internal standard in the solvent front zone allows their easy extraction followed by quantitation by HPLC. The exctraction procedure of the solute/s and internal standard can proceed from whole solute frontal zone or its part without lowering in accuracy of quantitative analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Nucleation of liquid droplets and voids in a stretched Lennard-Jones fcc crystal.

    Science.gov (United States)

    Baidakov, Vladimir G; Tipeev, Azat O

    2015-09-28

    The method of molecular dynamics simulation has been used to investigate the phase decay of a metastable Lennard-Jones face-centered cubic crystal at positive and negative pressures. It is shown that at high degrees of metastability, crystal decay proceeds through the spontaneous formation and growth of new-phase nuclei. It has been found that there exists a certain boundary temperature. Below this temperature, the crystal phase disintegrates as the result of formation of voids, and above, as a result of formation of liquid droplets. The boundary temperature corresponds to the temperature of cessation of a crystal-liquid phase equilibrium when the melting line comes in contact with the spinodal of the stretched liquid. The results of the simulations are interpreted in the framework of classical nucleation theory. The thermodynamics of phase transitions in solids has been examined with allowance for the elastic energy of stresses arising owing to the difference in the densities of the initial and the forming phases. As a result of the action of elastic forces, at negative pressures, the boundary of the limiting superheating (stretching) of a crystal approaches the spinodal, on which the isothermal bulk modulus of dilatation becomes equal to zero. At the boundary of the limiting superheating (stretching), the shape of liquid droplets and voids is close to the spherical one.

  12. Characterization of the MgO nano powder synthesized by using a liquid phase precursor method for plasma display panels protecting layer.

    Science.gov (United States)

    Jungo, C H; Lee, J Y; Yoon, D H

    2012-02-01

    The characterization of MgO nano powders that were synthesized using a conventional firing liquid phase precursor, rapid firing liquid phase precursor and rapid cooling firing liquid phase precursor were investigated as a function of the heating and cooling rates and the concentration of the impregnated Mg(NO3)2 x 6H2O solution from 1 to 20%. The relative intensity of diffraction peak in the MgO nano powder increased with increasing firing temperature from 800 to 1200 degrees C, indicating a higher crystalline MgO nano powder. In addition, the relative intensities of the MgO nano powder synthesized at the designated temperature showed similar behavior regardless of the impregnated Mg(NO3)2 x 6H2O solution concentration from the XRD analysis. The field emission scanning electron microscope and high resolution transmission electron microscope analysis showed that the size and shape of the MgO nano powder can be controlled by the temperature, the firing and cooling processes, and the impregnated Mg(NO3)2 x 6H2O solution concentration. Moreover, the CL spectra of the synthesized MgO nano powders showed a higher luminance efficiency than commercial MgO nano powder.

  13. Characterizing and Exploring the Formation Mechanism of Salt Deposition by Reusing Advanced-softened, Silica-rich, Oilfield-produced Water (ASOW) in Superheated Steam Pipeline

    Science.gov (United States)

    Dong, Bin; Xu, Ying; Lin, Senmin; Dai, Xiaohu

    2015-11-01

    To dispose of large volumes of oilfield-produced water, an environmentally friendly method that reuses advanced-softened, silica-rich, oilfield-produced water (ASOW) as feedwater was implemented via a 10-month pilot-scale test in oilfield. However, salt deposition detrimental to the efficiency and security of steam injection system was generated in superheated steam pipeline. To evaluate the method, the characteristics and formation mechanism of the deposition were explored. The silicon content and total hardness of the ASOW were 272.20 mg/L and 0.018 mg/L, respectively. Morphology and composition of the deposition were determined by scanning electron microscope-energy dispersive spectrometry (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Na2Si2O5, Na2CO3 and trace silanes were identified in the deposition. In addition, the solubility of the deposition was about 99%, suggesting that it is very different from traditional scaling. The results of a simulation experiment and thermal analysis system (TGA and TG-FTIR) proved that Na2CO3 and Si(OH)4 (gas) are involved in the formation of Na2Si2O5, which is ascribed mainly to the temperature difference between the superheated steam and the pipe wall. These findings provide an important reference for improving the reuse of ASOW and reducing its deposition.

  14. Quantized friction across ionic liquid thin films

    Science.gov (United States)

    Smith, Alexander M.; Lovelock, Kevin R. J.; Gosvami, Nitya Nand; Welton, Tom; Perkin, Susan

    Ionic liquids, salts in the liquid state under ambient conditions, are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion layers in the film. In contrast to molecular liquids, the friction coefficients differ for each layer due to their varying composition.

  15. Quantized friction across ionic liquid thin films.

    Science.gov (United States)

    Smith, Alexander M; Lovelock, Kevin R J; Gosvami, Nitya Nand; Welton, Tom; Perkin, Susan

    2013-10-07

    Ionic liquids - salts in the liquid state under ambient conditions - are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion layers in the film. In contrast to molecular liquids, the friction coefficients differ for each layer due to their varying composition.

  16. Spinodals and critical point using short-time dynamics for a simple model of liquid.

    Science.gov (United States)

    Loscar, Ernesto S; Ferrara, C Gastón; Grigera, Tomás S

    2016-04-07

    We have applied the short-time dynamics method to the gas-liquid transition to detect the supercooled gas instability (gas spinodal) and the superheated liquid instability (liquid spinodal). Using Monte Carlo simulation, we have obtained the two spinodals for a wide range of pressure in sub-critical and critical conditions and estimated the critical temperature and pressure. Our method is faster than previous approaches and allows studying spinodals without needing equilibration of the system in the metastable region. It is thus free of the extrapolation problems present in other methods, and in principle could be applied to systems such as glass-forming liquids, where equilibration is very difficult even far from the spinodal. We have also done molecular dynamics simulations, where we find the method again able to detect the both spinodals. Our results are compared with different previous results in the literature and show a good agreement.

  17. Determination of furanochromones and pyranocoumarins in drugs and Ammi visnaga fruits by combined solid-phase extraction-high-performance liquid chromatography and thin-layer chromatography-high-performance liquid chromatography.

    Science.gov (United States)

    Zgórka, G; Dragan, T; Głowniak, K; Basiura, E

    1998-02-27

    A new, simple and rapid solid-phase extraction method for the determination of furanochromones and pyranocoumarins in Ammi visnaga L. fruits and pharmaceuticals by reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The isolation of compounds examined was carried out on octadecyl BakerBond SPE columns using various concentrations of methanol, acetonitrile and tetrahydrofuran in water. High and reproducible recoveries were obtained. To compare the results of quantitative analysis a preparative TLC procedure was also elaborated and carried out.

  18. Measurements of mass and heat transfer at a liquid water surface during condensation or evaporation of a subnanometer thickness layer of water.

    Science.gov (United States)

    Miles, Rachael E H; Knox, Kerry J; Reid, Jonathan P; Laurain, Adèle M C; Mitchem, Laura

    2010-09-10

    A novel approach for exploring the molecular dynamics during condensation or evaporation at a liquid water surface is reported at pressures between 2 and 100 kPa. By introducing or removing a heating laser illuminating an optically tweezed aqueous aerosol droplet, the temperature of the droplet can be controlled with sub-mK accuracy and the change in size to reequilibrate with the surroundings monitored with subnanometer accuracy. The time constant for equilibration is shown to provide important insight into the coupling of heat and mass transfer during condensation or evaporation.

  19. External Heat Transfer in Moist Air and Superheated Steam for Softwood Drying%软木干燥中湿空气和过热蒸汽的外部传热

    Institute of Scientific and Technical Information of China (English)

    PANG Shusheng

    2004-01-01

    In kiln drying of softwood timber, external heat and moisture mass transfer coefficients are important in defining boundary temperature and moisture content at the wood surface. In addition, superheated steam drying of wood is a promising technology but this has not been widely accepted commercially, partially due to the lack of understanding of the drying phenomena occurred during drying. In this work, experimental investigation was performed to quantify the heat transfer between wood surface and surrounding moist air or superheated steam. In the experiment, saturated radiata pine sapwood samples were dried using dry-bulb/wet-bulb temperatures of 60℃/50℃,90℃/60℃, 120℃/70℃, 140℃/90℃, 160℃/90℃, 140℃/100℃ and 160℃/100℃. The last two schedules were for superheated steam drying as the wet-bulb temperature was set at 100℃. The circulation velocity over the board surface was controlled at 4.2 m·s-1. Two additional runs (90℃/60℃) using air velocities of 2.4 m·s-1 and 4.8 m·s-1were performed to check the effect of the circulation velocity. During drying, sample weight and temperatures at wood surface and different depths were continuously measured. From these measurements, changes in wood temperature and moisture content were calculated and external heat-transfer coefficient was determined for both the moist air and the superheated steam drying.

  20. Experimental research and design of superheated steam vacuum drying chest based on sea cucumber%海参过热蒸汽真空干燥装置的设计与试验

    Institute of Scientific and Technical Information of China (English)

    赵火英; 袁陆峰

    2012-01-01

    结合过热蒸汽干燥和真空干燥方式的特点,完成海参过热蒸汽真空干燥箱的设计.以海参为被干燥物料,进行不同工况下海参过热蒸汽真空干燥特性的试验研究,主要分析物料质量和脱水率的变化规律以及不同蒸汽温度下干燥速率的变化规律.结果表明:在相同真空度下,过热蒸汽温度越高,干燥速率越快,而且过热蒸汽干燥初期的速率最快.%The superheated steam vacuum drying chest has been designed by combining the good qualities of the superheated steam drying and the vacuum drying. Some kind of sea cucumber has been dried by superheated steam under different kinds of drying conditions. The regularity of quality, dehydration rate and drying velocity changes has been mainly analyzed. The results indicate that the temperature of superheated steam is the primary influencing factor of the drying velocity under the same vacuum pressure, and the higher temperature is, the faster drying velocity can reach. The drying velocity is the fastest at the initial stage along the drying process.

  1. MATHEMATICAL MODEL FOR CALCULATION OF MINIMUM PRESSURE PERTAINING TO DESTRUCTION OF SURFACE CORROSION LAYER DUE TO IMPACT OF WORKING LIQUID REVERSIVE STREAM

    Directory of Open Access Journals (Sweden)

    I. V. Kachanov

    2014-01-01

    Full Text Available Due to balance of external and internal force capacities a variation quasistatic problem has been solved in the paper. The problem allows to determine optimum values of α and β angles in the accepted field of sliding lines when destruction pressure takes on a minimum value pmin. It has been ascertained that the minimum pressure pmin which is necessary for destruction of a corrosion layer is registered at stream compression coefficient λ = 0,063 and the pressure is equal to 8-17 MPa for the investigated speed range v = 80-140 m/s.

  2. Studying the Regularities of High-Energy Flow Localization in Micro- and Nano-Layers at the Interface of Solid and Liquid Media

    Science.gov (United States)

    Mamaev, A. I.; Mamaeva, V. A.; Beletskaya, E. Yu.

    2017-08-01

    The paper presents the results of research performed by the modeling method and focusing on the distribution of material and energy flows at the interface of solid and liquid media under non-steady-state conditions. Modeling was performed using the case of two parallel oxidation-reduction reactions that occur under the impact of an external current supply of unlimited power. The identified regularities can be used when designing and arranging specific heterogeneous oxidation-reduction processes, in order to arrange local energy impact, including when one needs to form the nano-structured non-metallic inorganic coatings by microplasma method. Modeling demonstrates that nanosized localization of high-energy flows is possible at the media interface. Depending on pulse duration, the instantaneous energy can exceed the bond energy of chemical compounds. The identified regularities are true for description of non-steady-state heterogeneous oxidation-reduction reactions in chemistry, electrochemistry, catalysis and other areas of science and technology.

  3. Steam chemistry - interaction of chemical species with water, steam, and materials during evaporation, superheating, and condensation. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    Topics of this proceedings are: steam chemistry, supercritical water, effects of chemicals in steam (acetic acid, formic acid, phosphoric acid or other impurities); solubility and deposition, condensation processes and effect of impurities; nucleation; gas-liquid interfaces; steam treatment. (SR)

  4. Liquid-exfoliation of layered MoS2 for enhancing photocatalytic activity of TiO2/g-C3N4 photocatalyst and DFT study

    Science.gov (United States)

    Zhang, Weiping; Xiao, Xinyan; Li, Yang; Zeng, Xingye; Zheng, Lili; Wan, Caixia

    2016-12-01

    A new combined method of liquid-exfoliation and solvothermal process was employed for synthesizing TiO2/g-C3N4/MoS2 photocatalysts. In this typical process, the MoS2/g-C3N4 nano-sheets was prepared by liquid-exfoliation method from the bulk MoS2 and bulk carbon nitride in the alcohol system, and then the TiO2 nanoparticles (NPs) were grown on the MoS2/g-C3N4 nano-sheets by in-situ synthesis technique. The evaluation of photocatalytic degradation reaction showed that the as-prepared TiO2/g-C3N4/MoS2 photocatalysts exhibited higher photocatalytic activity as compared to the pure TiO2, pure g-C3N4 and TiO2/g-C3N4 composite. The enhanced photocatalytic activities of TiO2/g-C3N4/MoS2 photocatalysts are attributed to positive synergetic effect of heterostructure between g-C3N4/MoS2 hybrid and TiO2 nano-structure, which not only enlarged spectral response and also enhanced the utilization rate of photons. Furthermore, DFT (Density Functional Theory) was employed to investigate the formation mechanism of the interfaces between TiO2 NPs and g-C3N4/MoS2 nano-sheets, which would be of great importance in revealing the electron-transfer at the interfaces of composites and the mechanism for the great improvement for the activity of TiO2/g-C3N4/MoS2 photocatalysts.

  5. A molecular dynamics simulation study of the electric double layer and capacitance of [BMIM][PF6] and [BMIM][BF4] room temperature ionic liquids near charged surfaces.

    Science.gov (United States)

    Hu, Zongzhi; Vatamanu, Jenel; Borodin, Oleg; Bedrov, Dmitry

    2013-09-14

    A molecular dynamics simulation study of electric double layer (EDL) structure and differential capacitance (DC) of two 1-butyl-3-methylimidazolium (BMIM)-based room temperature ionic liquids, i.e. [BMIM][BF4] and [BMIM][PF6], has been conducted on basal and prismatic graphite as well as (001) and (011) gold electrode surfaces. The influence of the electrode surface and electrolyte structure on electrode capacitance and EDL structure are discussed. For a given electrode surface both the [BMIM][BF4] and [BMIM][PF6] electrolytes generate very similar DC and EDL structures. The DC for these ionic liquids in contact with atomically flat surfaces (i.e. basal graphite and (001)Au) shows very small variations within the electrolyte chemical stability potential window and fluctuates around an average value of ∼5 μF cm(-2). On atomically more corrugated surfaces (i.e., Au(011) and prismatic graphite) the DC shows more variation with electrode potential and depends on the correspondence between dimensions of the surface roughness and electrolyte ion sizes. The trends and dependencies obtained for DC are used to discriminate between mutually contradictory experimental data reported in the literature for related systems.

  6. “固化水层”模型拓展石英晶体微天平的应用%Applications of Quartz Crystal Microbalance with Solidified Liquid Layer Model

    Institute of Scientific and Technical Information of China (English)

    顾莉娟; 汪杰; 马宏伟

    2013-01-01

    Quartz crystal microbalance (QCM) has many advantages in research,but the data interpretation has hindered its applications in many research fields,especially for application in liquid.Recently,we proposed'solidified liquid layer' (SLL) model to simplify the data analysis.In this article,some missing evidences are provided to demonstrate the SLL model.The thickness result from ellipsometry accords with the result from the SLL model.The SLL model predicts that 1 Hz signal respond to a 0.18-nm change of TSLL,which greatly improve the resolution of QCMs in liquid.These researches effectively improve our understanding in the nature of Au—S bond breakage and its breakage process.Our results show that the SLL model will improve the applications of QCM in many fields.%石英晶体微天平(QCM)在液态环境下的应用一直由于数据分析复杂而受到限制.最近,我们提出了“固化水层”模型(SLL)以简化QCM数据分析过程.本文进一步提供了SLL模型的有关数据.根据SLL模型,1 Hz QCM频率信号对应于0.18 nm SLL层厚度的变化,而大多数商业的QCM均可以达到该精度.因此,根据SLL模型设计的检测方案将具有很高的灵敏度.QCM作为生物传感器的应用也得以拓展,可以相信SLL模型将大大增强QCM的分析能力.

  7. Ionic liquids as additive in thin layer chromatography on separation of amino acids%离子液体作薄层色谱添加剂对氨基酸分离的研究

    Institute of Scientific and Technical Information of China (English)

    刘建平; 何丽君

    2011-01-01

    The separation of two alkaline amino acids ( argi-nine and lysine) was performed using 1-butyl-3-methylimid-azolium tetrafluoroborate ionic liquid ( [ Bmim ] BF4 ) as the eluent additives in thin layer chromatography. The addition of ionic liquid improved the separation the free silanol group markedly. The retardation factor ( R1) of the analytes firstly increased and then remained constant with the increase of the concentration of ionic liquids. In addition,the comparison results showed that the inhibition effect of [ Bmim ] PF6 for free silanol group was more effective than that of [ Bmim] BF4.%将1-丁基-3-甲基咪唑基四氟硼酸盐([Bmim]BF4)离子液体作为薄层色谱展开剂添加剂,讨论了[Bmim]BF4浓度对精氨酸和赖氨酸两种碱性氨基酸分离的影响.结果表明:添加离子液体能有效改善碱性氨基酸的展开效果,而且分析物的Rf值随离子液体浓度的增加而增加,浓度增加到一定后Rf保持不变.另外,比较了[Bmim]PF6和[Bmim]BF4两种离子液体对自由硅羟基抑制作用的效果,前者对自由硅羟基的抑制作用比后者更有效.

  8. Quality assessment of Cinnamomi Ramulus by the simultaneous analysis of multiple active components using high-performance thin-layer chromatography and high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Xiaoxue; He, Jiao; Xu, Huarong; Bi, Kaishun; Li, Qing

    2014-09-01

    A novel and improved method for the quality assessment of Cinnamomi Ramulus was developed and completely validated. The method was established using fingerprint technology and simultaneous quantitative determination of six main marker compounds including coumarin, cinnamic alcohol, cinnamic acid, 2-methoxy cinnamic acid, cinnamaldehyde, and 2-methoxy cinnamaldehyde in the herbal medicine for the first time. A newly developed high-performance thin-layer chromatography method, which achieved simultaneous definition of five marker components by comparing the colors and retardation factor values of the bands in high-performance thin-layer chromatography, was first used for the authentication of Cinnamomi Ramulus. The fingerprints of 26 batches of herbal samples from different regions of China showed very similar chromatographic patterns that were evaluated by similarity analysis and hierarchical clustering analysis. In addition, six marker compounds were simultaneously determined using single standard to determine multiple components by the relative response factors. Compared with the external standard method, the new quantitative method was validated to determine multiple compounds in 26 batches of Cinnamomi Ramulus samples. All results demonstrated that the simple and rapid method could be effectively utilized for the quality control of Cinnamomi Ramulus. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Solid on liquid deposition

    Energy Technology Data Exchange (ETDEWEB)

    Charmet, J., E-mail: jerome.charmet@he-arc.c [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Banakh, O.; Laux, E.; Graf, B.; Dias, F.; Dunand, A.; Keppner, H. [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Gorodyska, G.; Textor, M. [BioInterface group, ETHZ, Wolfgang-Pauli-Strasse 10, ETH Hoenggerberg HCI H 525 8093 Zuerich (Switzerland); Noell, W.; Rooij, N.F. de [Ecole Polytechnique Federale de Lausanne, Institute of Microengineering, Sensors, Actuators and Microsystems laboratory, Rue Jaquet Droz 1, 2000 Neuchatel (Switzerland); Neels, A.; Dadras, M.; Dommann, A.; Knapp, H. [Centre Suisse d' Electronique et de Microtechnique SA, Rue Jacquet-Droz 1, 2002 Neuchatel (Switzerland); Borter, Ch.; Benkhaira, M. [COMELEC SA, Rue de la Paix 129, 2300 La Chaux-de-Fonds (Switzerland)

    2010-07-01

    A process for the deposition of a solid layer onto a liquid is presented. The polymer poly-di-chloro-para-xylylene, also known as Parylene C, was grown on low vapour pressure liquids using the conventional low pressure chemical vapour deposition process. A reactor was built and a process developed to enable the deposition of Parylene C at atmospheric pressure over high vapour pressure liquids. It was used to deposit Parylene C over water among others. In all cases Parylene C encapsulated the liquid without influencing its initial shape. The results presented here show also that the Parylene C properties are not affected by its growth on liquid templates and the roughness of the Parylene C surface in contact with the liquid during the deposition is extremely low.

  10. Determination of 1-naphthol and 2-naphthol from environmental waters by magnetic solid phase extraction with Fe@MgAl-layered double hydroxides nanoparticles as the adsorbents prior to high performance liquid chromatography.

    Science.gov (United States)

    Zhou, Qingxiang; Lei, Man; Li, Jing; Zhao, Kuifu; Liu, Yongli

    2016-04-01

    Magnetic Fe@MgAl-layered double hydroxides (MgAl-LDHs) composite was firstly synthesized by coating MgAl-layered double hydroxides on the surface of the dispersed nanoscale zero valent irons with co-precipitation method and characterized by transmission electron microscopy and X-ray diffraction techniques. The synthesized Fe@MgAl-LDHs nanoparticles were investigated for magnetic solid phase extraction (MSPE) of 1-naphthol and 2-naphthol from the water samples. The elutent containing 1-naphthol and 2-naphthol was analyzed by high performance liquid chromatography with variable wavelength detection (HPLC-UV). Under optimal conditions, there is good linear relationship between the concentration and the peak area in the range of 0.5-200 μgL(-1) with the correlation coefficients (r(2)) above 0.998 for 1-naphthol and 2-naphthol. The limits of detection were 0.22 μgL(-1) and 0.19 μgL(-1) for 1-naphthol and 2-naphthol, respectively, and precisions were both below 2.5% (n=6). The real water analysis demonstrated that the spiked recoveries were in the range of 79.2-80.9% (n=3). All these results indicated that the developed MSPE-HPLC-UV method was proved to be an efficient tool for the analysis of naphthols.

  11. Stability Limits of the Liquid Phase in the Layered Mo/Pb/Mo, Mo/Bi/Mo and Mo/In/Mo Film Systems

    Directory of Open Access Journals (Sweden)

    S.I. Petrushenko

    2016-12-01

    Full Text Available The results of the study of supercooling of the fusible metals films between the continuous layers of molybdenum during the crystallization are given. Due to an original in situ technique based on the changes of resistance of samples during heating and cooling directly in the vacuum chamber the values of supercooling in Mo/Pb/Mo, Mo/Bi/Mo, Mo/In/Mo films are determined and the influence of the morphological structure of the bismuth inclusions on the temperature and nature of its supercooled melt crystallization has been found. The substrate temperature change during the condensation of samples, accompanied by a corresponding change in their microstructure, allows realizing both avalanche and diffuse crystallization and changing of supercooling value in the range of 60 to 180 K in Mo/Bi/Mo films.

  12. Energy and Exergy Analysis of a Novel Efficient Combined Process by Hydrothermal Degradation and Superheated Steam Drying of Degradable Organic Wastes

    Institute of Scientific and Technical Information of China (English)

    Shuqing GUO; Yunhan XIAO; Wendong TIAN; Zhedian ZHANG

    2006-01-01

    This paper considers the combination of hydrothermal degradation (HTD) and superheated steam (SHS) drying in disposal and processing of degradable organic wastes in municipal solid wastes (MSW). In SHS drying, a fraction of dryer thermal energy input can be recovered and used to satisfy the heat requirement in maintaining the HTD operating temperature. Both energy and exergy analysis are applied to the combined process. The analysis covers ranges of dryer inlet temperatures of 202.38-234.19℃ and feed water content of 32.5-65%. Thermal energy analysis shows that the combination of HTD and SHS drying can achieve thermal energy self-sufficiency (TES)by manipulating process variables. The exergy analysis indicates the location, type, and magnitude of the exergy losses during the whole process by applying the second law of thermodynamics.

  13. Are All Obsidians Super-Heated? Insights from Observations of Crystallization Kinetics in Experiments on Glass Mountain Obsidians (Long Valley, CA)

    Science.gov (United States)

    Waters, L.; Andrews, B. J.

    2015-12-01

    The Glass Mountain obsidians (Long Valley, CA) are crystal-poor (obsidians, if the mineral assemblage is phenocrystic. Results of high-resolution SEM mapping and electron microprobe analysis of a Glass Mountain sample reveal that the obsidian is saturated in nine phases (sanidine + quartz + plagioclase + ilmenite + titanomagnetite + zircon + apatite + allanite + biotite). Sanidine (Or78-Or35) and quartz occur in the largest abundances, and plagioclase (obsidians, requires that the mechanism that produced these obsidians have an associated kinetic effect that strongly hinders nucleation. Decompression and cooling experiments, conducted in this study and from the literature, demonstrate that the simplest way to hinder nucleation is to initiate degassing or cooling from super-liquidus conditions. Therefore, the Glass Mountain obsidians were super-heated prior to crystallization, achieved either by fluid under-saturated decompression from a crystalline mush or H2O-saturated partial melting.

  14. Nondestructive Characterization of Residual Threading Dislocation Density in HgCdTe Layers Grown on CdZnTe by Liquid-Phase Epitaxy

    Science.gov (United States)

    Fourreau, Y.; Pantzas, K.; Patriarche, G.; Destefanis, V.

    2016-09-01

    The performance of mercury cadmium telluride (MCT)-based infrared (IR) focal-plane arrays is closely related to the crystalline perfection of the HgCdTe thin film. In this work, Te-rich, (111)B-oriented HgCdTe epilayers grown by liquid-phase epitaxy on CdZnTe substrates have been studied. Surface atomic steps are shown on as-grown MCT materials using atomic force microscopy (AFM) and white-light interferometry (WLI), suggesting step-flow growth. Locally, quasiperfect surface spirals are also evidenced. A demonstration is given that these spirals are related to the emergence of almost pure screw threading dislocations. A nondestructive and quantitative technique to measure the threading dislocation density is proposed. The technique consists of counting the surface spirals on the as-grown MCT surface from images obtained by either AFM or WLI measurements. The benefits and drawbacks of both destructive—chemical etching of HgCdTe dislocations—and nondestructive surface imaging techniques are compared. The nature of defects is also discussed. Finally, state-of-the-art threading dislocation densities in the low 104 cm-2 range are evidenced by both etch pit density (EPD) and surface imaging measurements.

  15. Dynamics of vapor bubbles growth at boiling resulting from enthalpy excess of the surrounding superheated liquid and sound pulses generated by bubbles

    Science.gov (United States)

    Dorofeev, B. M.; Volkova, V. I.

    2016-01-01

    The results of experiments investigating the exponential dependence of the vapor bubble radius on time at saturated boiling are generalized. Three different methods to obtain this dependence are suggested: (1) by the application of the transient heat conduction equation, (2) by using the correlations of energy conservation, and (3) by solving a similar electrodynamic problem. Based on the known experimental data, the accuracy of the dependence up to one percent and a few percent accuracy of its description based on the sound pressure generated by a vapor bubble have been determined. A significant divergence of the power dependence of the vapor bubble radius on time (with an exponent of 1/2) with the experimental results and its inadequacy for the description of the sound pulse generated by the bubble have been demonstrated.

  16. An Approach to Solid-State Electrical Double Layer Capacitors Fabricated with Graphene Oxide-Doped, Ionic Liquid-Based Solid Copolymer Electrolytes

    Directory of Open Access Journals (Sweden)

    N. F. A. Fattah

    2016-06-01

    Full Text Available Solid polymer electrolyte (SPE composed of semi-crystalline poly (vinylidene fluoride-hexafluoropropylene [P(VdF-HFP] copolymer, 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulphonyl imide [EMI-BTI] and graphene oxide (GO was prepared and its performance evaluated. The effects of GO nano-filler were investigated in terms of enhancement in ionic conductivity along with the electrochemical properties of its electrical double layer capacitors (EDLC. The GO-doped SPE shows improvement in ionic conductivity compared to the P(VdF-HFP-[EMI-BTI] SPE system due to the existence of the abundant oxygen-containing functional group in GO that assists in the improvement of the ion mobility in the polymer matrix. The complexation of the materials in the SPE is confirmed in X-ray diffraction (XRD and thermogravimetric analysis (TGA studies. The electrochemical performance of EDLC fabricated with GO-doped SPE is examined using cyclic voltammetry and charge–discharge techniques. The maximum specific capacitance obtained is 29.6 F∙g−1, which is observed at a scan rate of 3 mV/s in 6 wt % GO-doped, SPE-based EDLC. It also has excellent cyclic retention as it is able keep the performance of the EDLC at 94% even after 3000 cycles. These results suggest GO doped SPE plays a significant role in energy storage application.

  17. Dynamic air layer on textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model. © 2013 American Chemical Society.

  18. Dynamic air layer on textured superhydrophobic surfaces.

    Science.gov (United States)

    Vakarelski, Ivan U; Chan, Derek Y C; Marston, Jeremy O; Thoroddsen, Sigurdur T

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model.

  19. Liquid-Liquid Phase Transition in Nanoconfined Silicon Carbide.

    Science.gov (United States)

    Wu, Weikang; Zhang, Leining; Liu, Sida; Ren, Hongru; Zhou, Xuyan; Li, Hui

    2016-03-01

    We report theoretical evidence of a liquid-liquid phase transition (LLPT) in liquid silicon carbide under nanoslit confinement. The LLPT is characterized by layering transitions induced by confinement and pressure, accompanying the rapid change in density. During the layering transition, the proportional distribution of tetracoordinated and pentacoordinated structures exhibits remarkable change. The tricoordinated structures lead to the microphase separation between silicon (with the dominant tricoordinated, tetracoordinated, and pentacoordinated structures) and carbon (with the dominant tricoordinated structures) in the layer close to the walls. A strong layer separation between silicon atoms and carbon atoms is induced by strong wall-liquid forces. Importantly, the pressure confinement phase diagram with negative slopes for LLPT lines indicates that, under high pressure, the LLPT is mainly confinement-induced, but under low pressure, it becomes dominantly pressure-induced.

  20. Liquid metal enabled microfluidics.

    Science.gov (United States)

    Khoshmanesh, Khashayar; Tang, Shi-Yang; Zhu, Jiu Yang; Schaefer, Samira; Mitchell, Arnan; Kalantar-Zadeh, Kourosh; Dickey, Michael D

    2017-03-14

    Several gallium-based liquid metal alloys are liquid at room temperature. As 'liquid', such alloys have a low viscosity and a high surface tension while as 'metal', they have high thermal and electrical conductivities, similar to mercury. However, unlike mercury, these liquid metal alloys have low toxicity and a negligible vapor pressure, rendering them much safer. In comparison to mercury, the distinguishing feature of these alloys is the rapid formation of a self-limiting atomically thin layer of gallium oxide over their surface when exposed to oxygen. This oxide layer changes many physical and chemical properties of gallium alloys, including their interfacial and rheological properties, which can be employed and modulated for various applications in microfluidics. Injecting liquid metal into microfluidic structures has been extensively used to pattern and encapsulate highly deformable and reconfigurable electronic devices including electrodes, sensors, antennas, and interconnects. Likewise, the unique features of liquid metals have been employed for fabricating miniaturized microfluidic components including pumps, valves, heaters, and electrodes. In this review, we discuss liquid metal enabled microfluidic components, and highlight their desirable attributes including simple fabrication, facile integration, stretchability, reconfigurability, and low power consumption, with promising applications for highly integrated microfluidic systems.