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Sample records for semi-batch bubble column

  1. CO2 Absorption from Biogas by Glycerol: Conducted in Semi-Batch Bubble Column

    Science.gov (United States)

    puji lestari, Pratiwi; Mindaryani, Aswati; Wirawan, S. K.

    2018-03-01

    Biogas is a renewable energy source that has been developed recently. The main contents of Biogas itself are Methane and carbon dioxide (CO2) where Methane is the main component of biogas with CO2 as the highest impurities. The quality of biogas depends on the CO2 content, the lower CO2 levels, the higher biogas quality. Absorption is one of the methods to reduce CO2 level. The selections of absorbent and appropriate operating parameters are important factors in the CO2 absorption from biogas. This study aimed to find out the design parameters for CO2 absorption using glycerol that represented by the overall mass transfer coefficient (KLa) and Henry’s constant (H). This study was conducted in semi-batch bubble column. Mixed gas was contacted with glycerol in a bubble column. The concentration of CO2 in the feed gas inlet and outlet columns were analysed by Gas Chromatograph. The variables observed in this study were superficial gas velocity and temperatures. The results showed that higher superficial gas velocity and lower temperature increased the rate of absorption process and the amount of CO2 absorbed.

  2. Ozonation of acid yellow 17 dye in a semi-batch bubble column

    International Nuclear Information System (INIS)

    Lackey, Laura W.; Mines, Richard O.; McCreanor, Philip T.

    2006-01-01

    A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid yellow 17 dye from water. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The ozone consumed to apparent dye removal ratio ranged from 2 to 15,000 mg ozone per mg of dye decolorized and was dependent on both ozonation time and apparent dye concentration. The biodegradability of the dye wastewater was evaluated by monitoring changes in 5-day biochemical oxygen demand (BOD 5 ) with respect to chemical oxygen demand (COD). Results indicate that the wastewater biodegradability increased with an increase in ozonation time. Film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10-15 min of ozonation, the system could be characterized by a fast, pseudo-first-order regime. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented

  3. The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors

    DEFF Research Database (Denmark)

    Tirunehe, Gossay; Norddahl, B.

    2016-01-01

    Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air–water and air–CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas–liquid mediums. CMC....../s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular...... membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (KLa) by a factor of 1.2–1.9 compared to the flat sheet membrane....

  4. Characterization of Bubble Size Distributions within a Bubble Column

    OpenAIRE

    Shahrouz Mohagheghian; Brian R. Elbing

    2018-01-01

    The current study experimentally examines bubble size distribution (BSD) within a bubble column and the associated characteristic length scales. Air was injected into a column of water via a single injection tube. The column diameter (63–102 mm), injection tube diameter (0.8–1.6 mm) and superficial gas velocity (1.4–55 mm/s) were varied. Large samples (up to 54,000 bubbles) of bubble sizes measured via 2D imaging were used to produce probability density functions (PDFs). The PDFs were used to...

  5. Bubble Size Distribution in a Vibrating Bubble Column

    Science.gov (United States)

    Mohagheghian, Shahrouz; Wilson, Trevor; Valenzuela, Bret; Hinds, Tyler; Moseni, Kevin; Elbing, Brian

    2016-11-01

    While vibrating bubble columns have increased the mass transfer between phases, a universal scaling law remains elusive. Attempts to predict mass transfer rates in large industrial scale applications by extrapolating laboratory scale models have failed. In a stationary bubble column, mass transfer is a function of phase interfacial area (PIA), while PIA is determined based on the bubble size distribution (BSD). On the other hand, BSD is influenced by the injection characteristics and liquid phase dynamics and properties. Vibration modifies the BSD by impacting the gas and gas-liquid dynamics. This work uses a vibrating cylindrical bubble column to investigate the effect of gas injection and vibration characteristics on the BSD. The bubble column has a 10 cm diameter and was filled with water to a depth of 90 cm above the tip of the orifice tube injector. BSD was measured using high-speed imaging to determine the projected area of individual bubbles, which the nominal bubble diameter was then calculated assuming spherical bubbles. The BSD dependence on the distance from the injector, injector design (1.6 and 0.8 mm ID), air flow rates (0.5 to 5 lit/min), and vibration conditions (stationary and vibration conditions varying amplitude and frequency) will be presented. In addition to mean data, higher order statistics will also be provided.

  6. Characterization of Bubble Size Distributions within a Bubble Column

    Directory of Open Access Journals (Sweden)

    Shahrouz Mohagheghian

    2018-02-01

    Full Text Available The current study experimentally examines bubble size distribution (BSD within a bubble column and the associated characteristic length scales. Air was injected into a column of water via a single injection tube. The column diameter (63–102 mm, injection tube diameter (0.8–1.6 mm and superficial gas velocity (1.4–55 mm/s were varied. Large samples (up to 54,000 bubbles of bubble sizes measured via 2D imaging were used to produce probability density functions (PDFs. The PDFs were used to identify an alternative length scale termed the most frequent bubble size (dmf and defined as the peak in the PDF. This length scale as well as the traditional Sauter mean diameter were used to assess the sensitivity of the BSD to gas injection rate, injector tube diameter, injection tube angle and column diameter. The dmf was relatively insensitive to most variation, which indicates these bubbles are produced by the turbulent wakes. In addition, the current work examines higher order statistics (standard deviation, skewness and kurtosis and notes that there is evidence in support of using these statistics to quantify the influence of specific parameters on the flow-field as well as a potential indicator of regime transitions.

  7. The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors.

    Science.gov (United States)

    Tirunehe, Gossaye; Norddahl, B

    2016-04-01

    Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air-water and air-CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas-liquid mediums. CMC solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas-liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (U(G)) range of 0.0004-0.0025 m/s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (K(L)a) by a factor of 1.2-1.9 compared to the flat sheet membrane.

  8. Discrete bubble modeling for a micro-structured bubble column

    NARCIS (Netherlands)

    Jain, D.; Lau, Y.M.; Kuipers, J.A.M.; Deen, N.G.

    2013-01-01

    Gas–liquid flows with solid catalyst particles are encountered in many applications in the chemical, petrochemical, pharmaceutical industries, etc. Most commonly, two reactor types are applied for large scale in the industry. They are slurry bubble column and trickle bed reactors. Both of these

  9. Bubble properties of heterogeneous bubbly flow in a square bubble column

    NARCIS (Netherlands)

    Bai, Wei; Deen, Niels G.; Kuipers, J.A.M.

    2010-01-01

    The present work focuses on the measurements of bubble properties in heterogeneous bubbly flows in a square bubble column. A four-point optical fibre probe was used for this purpose. The accuracy and intrusive effect of the optical probe was investigated first. The results show that the optical

  10. On Stability of a Bubble Column

    Czech Academy of Sciences Publication Activity Database

    Růžička, Marek

    2013-01-01

    Roč. 91, č. 2 (2013), s. 191-203 ISSN 0263-8762 R&D Projects: GA ČR GA104/07/1110 Institutional support: RVO:67985858 Keywords : bubble column * flow regimes * steady solution Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.281, year: 2013

  11. Computational analysis of ozonation in bubble columns

    International Nuclear Information System (INIS)

    Quinones-Bolanos, E.; Zhou, H.; Otten, L.

    2002-01-01

    This paper presents a new computational ozonation model based on the principle of computational fluid dynamics along with the kinetics of ozone decay and microbial inactivation to predict the performance of ozone disinfection in fine bubble columns. The model can be represented using a mixture two-phase flow model to simulate the hydrodynamics of the water flow and using two transport equations to track the concentration profiles of ozone and microorganisms along the height of the column, respectively. The applicability of this model was then demonstrated by comparing the simulated ozone concentrations with experimental measurements obtained from a pilot scale fine bubble column. One distinct advantage of this approach is that it does not require the prerequisite assumptions such as plug flow condition, perfect mixing, tanks-in-series, uniform radial or longitudinal dispersion in predicting the performance of disinfection contactors without carrying out expensive and tedious tracer studies. (author)

  12. Experimental and numerical investigation of bubble column reactors

    NARCIS (Netherlands)

    Bai, W.

    2010-01-01

    Due to various advantages, such as simple geometry, ease of operation, low operating and maintenance costs, excellent heat and mass transfer characteristics, bubble column reactors are frequently used in chemical, petrochemical, biochemical, pharmaceutical, metallurgical industries for a variety of

  13. Two-fluid model LES of a bubble column

    International Nuclear Information System (INIS)

    Brahma N Reddy Vanga; Martin A Lopez de Bertodano; Eckhard Krepper; Alexandr Zaruba; Horst-Michael Prasser

    2005-01-01

    The hydrodynamics of a rectangular bubble column operating in the dispersed bubbly regime has been numerically investigated using a two-fluid model Large Eddy Simulation (LES). Experimental data were obtained to validate the model. LES computational fluid dynamic calculations of the transient flow for the bubble column were performed to account for the turbulence in the liquid phase. The computational mesh is of the same scale as the bubble size. The sub grid-scale Reynolds stresses were calculated with the Smagorinsky model. Furthermore, the effect of the bubbles on the turbulence in the continuous phase was modeled using Sato's eddy viscosity model for bubble-induced turbulence. Mean quantities were computed by averaging over a time period that was longer than the dynamic time scales of the turbulence, in particular the void fraction and the average velocity of the bubbles. A systematic analysis of the effect of the interfacial momentum transfer terms on these quantities has been conducted. The bubble column was locally aerated using a sparger located in the center of the bottom plate. The experimental studies involve wire-mesh tomography measurements for void fraction and bubble size distributions and digital image processing of high speed camera images for estimation of bubble velocities, size distributions and flow patterns. Experiments were performed for various aspect ratios (height of water column to width ratio) and superficial gas velocities. It was found that the non-drag bubble forces play a very prominent role in the predicting the correct flow pattern and void fraction distributions. In the calculations, the lift force and the wall force were considered. A 'wall peak' in the time averaged void fraction distribution has been experimentally observed and this cannot be predicted without including these non-drag forces in the numerical calculations. In this paper, experimental data are compared with the results of the numerical simulations. (authors)

  14. Tritium extraction from Pb-17Li by bubble columns

    International Nuclear Information System (INIS)

    Malara, C.

    1995-01-01

    Tritium extraction from the Pb-17Li liquid breeder of a fusion reactor can be efficiently carried out by bubble columns. To this aim, a mathematical model describing the complex fluid-dynamics of a bubble extractor is here presented. The model equations are made dimensionless and, together with the proper boundary conditions, numerically solved by the orthogonal collocation technique. Moreover, in order to better understand the role played by the different parameters in determining the performance of a bubble column, a closed solution of the model is obtained by introducing suitable hypotheses. A parametric analysis of the extraction efficiency of a bubble column as a function of the process parameters is carried out and, on this basis, the design of a tritium extraction system from the Pb-17Li breeder of a DEMO-type fusion reactor is proposed. 17 refs., 3 figs., 2 tabs

  15. Investigation of Gas Holdup in a Vibrating Bubble Column

    Science.gov (United States)

    Mohagheghian, Shahrouz; Elbing, Brian

    2015-11-01

    Synthetic fuels are part of the solution to the world's energy crisis and climate change. Liquefaction of coal during the Fischer-Tropsch process in a bubble column reactor (BCR) is a key step in production of synthetic fuel. It is known from the 1960's that vibration improves mass transfer in bubble column. The current study experimentally investigates the effect that vibration frequency and amplitude has on gas holdup and bubble size distribution within a bubble column. Air (disperse phase) was injected into water (continuous phase) through a needle shape injector near the bottom of the column, which was open to atmospheric pressure. The air volumetric flow rate was measured with a variable area flow meter. Vibrations were generated with a custom-made shaker table, which oscillated the entire column with independently specified amplitude and frequency (0-30 Hz). Geometric dependencies can be investigated with four cast acrylic columns with aspect ratios ranging from 4.36 to 24, and injector needle internal diameters between 0.32 and 1.59 mm. The gas holdup within the column was measured with a flow visualization system, and a PIV system was used to measure phase velocities. Preliminary results for the non-vibrating and vibrating cases will be presented.

  16. Application of coalescence and breakup models in a discrete bubble model for bubble columns

    NARCIS (Netherlands)

    van den Hengel, E.I.V.; Deen, N.G.; Kuipers, J.A.M.

    2005-01-01

    In this work, a discrete bubble model (DBM) is used to investigate the hydrodynamics, coalescence, and breakup occurring in a bubble column. The DBM, originally developed by Delnoij et al. (Chem. Eng. Sci. 1997, 52, 1429-1458; Chem. Eng. Sci. 1999, 54, 2217-2226),1,2 was extended to incorporate

  17. Scales and structures in bubbly flows. Experimental analysis of the flow in bubble columns and in bubbling fluidized beds

    NARCIS (Netherlands)

    Groen, J.S.

    2004-01-01

    In this project a detailed experimental analysis was performed of the dynamic flow field in bubbly flows, with the purpose of determining local hydrodynamics and scale effects. Measurements were done in gas-liquid systems (air-water bubble columns) and in gas-solid systems (air-sand bubbing

  18. Hydrodynamic models for slurry bubble column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Gidaspow, D. [IIT Center, Chicago, IL (United States)

    1995-12-31

    The objective of this investigation is to convert a {open_quotes}learning gas-solid-liquid{close_quotes} fluidization model into a predictive design model. This model is capable of predicting local gas, liquid and solids hold-ups and the basic flow regimes: the uniform bubbling, the industrially practical churn-turbulent (bubble coalescence) and the slugging regimes. Current reactor models incorrectly assume that the gas and the particle hold-ups (volume fractions) are uniform in the reactor. They must be given in terms of empirical correlations determined under conditions that radically differ from reactor operation. In the proposed hydrodynamic approach these hold-ups are computed from separate phase momentum balances. Furthermore, the kinetic theory approach computes the high slurry viscosities from collisions of the catalyst particles. Thus particle rheology is not an input into the model.

  19. Axial and Radial Gas Holdup in Bubble Column Reactor

    International Nuclear Information System (INIS)

    Wagh, Sameer M.; Ansari, Mohashin E Alan; Kene, Pragati T.

    2014-01-01

    Bubble column reactors are considered the reactor of choice for numerous applications including oxidation, hydrogenation, waste water treatment, and Fischer-Tropsch (FT) synthesis. They are widely used in a variety of industrial applications for carrying out gas-liquid and gas-liquid-solid reactions. In this paper, the computational fluid dynamics (CFD) model is used for predicting the gas holdup and its distribution along radial and axial direction are presented. Gas holdup increases linearly with increase in gas velocity. Gas bubbles tends to concentrate more towards the center of the column and follows a wavy path

  20. The terminal rise velocity of bubble in a liquid column

    International Nuclear Information System (INIS)

    Mario Ar Talaia

    2005-01-01

    Full text of publication follows: As it is know, buoyancy and drag forces govern bubble rising velocity in a liquid column. These forces strongly depend on fluid proprieties and gravity as well as bubble equivalent diameter. The present work reports about a set of experiments bubble rising velocity in a liquid column using liquid with different kinematics viscosity. Records of terminal velocity were obtained, over a wide range of dynamic viscosity. The results show that the terminal rise velocity of bubble is strongly influenced by the effect of kinematics viscosity. The interpretation of physical phenomenon is considered. The set data permit to have a game of terminal velocities of 7.96 - 32.86 cm.s -1 with Reynolds number of 0.8 - 7491. The bubble movement is recorded with a camera video, which will be presented. Our aim goal is to present an original set data and the results are discussed in light of theory of two-phase flow. Prediction of bubble terminal velocity is discussed, so as, the range of applicability. (author)

  1. Study of droplet entrainment from bubbling surface in a bubble column

    International Nuclear Information System (INIS)

    Ramirez de Santiago, M.

    1991-05-01

    In a bubble column droplets are ejected from the free surface by bubble bursting or splashing. Depending on their size, the droplets are partly carried away by the streaming gas or fall back to the bubbling surface by gravity force. Experiments have been carried out to determine the void fraction in the column by means of an optical probe. In the interfacial zone the bubble bursting process was captured with a high-speed video camera. Simultaneous measurements were made of size and velocity of droplets at several distances from the bubbling surface with a Phase-Doppler Anemometry. The bubble column can be divided into three regions: A lower zone with a flat profile of the local void fraction, a central zone where the flow regime is steady and an upper zone where the local void fraction grows rapidly. A two-parameter log-normal distribution function was proposed in order to describe the polydisperse distribution of droplet-size. Results were obtained concerning the entrainment, concentration, volume fraction and interfacial area of droplets. Finally, it was found that the turbulence intensity affects the droplet terminal velocity for droplets smaller than the Kolmogorov microscale [fr

  2. Metabolic modeling of synthesis gas fermentation in bubble column reactors.

    Science.gov (United States)

    Chen, Jin; Gomez, Jose A; Höffner, Kai; Barton, Paul I; Henson, Michael A

    2015-01-01

    A promising route to renewable liquid fuels and chemicals is the fermentation of synthesis gas (syngas) streams to synthesize desired products such as ethanol and 2,3-butanediol. While commercial development of syngas fermentation technology is underway, an unmet need is the development of integrated metabolic and transport models for industrially relevant syngas bubble column reactors. We developed and evaluated a spatiotemporal metabolic model for bubble column reactors with the syngas fermenting bacterium Clostridium ljungdahlii as the microbial catalyst. Our modeling approach involved combining a genome-scale reconstruction of C. ljungdahlii metabolism with multiphase transport equations that govern convective and dispersive processes within the spatially varying column. The reactor model was spatially discretized to yield a large set of ordinary differential equations (ODEs) in time with embedded linear programs (LPs) and solved using the MATLAB based code DFBAlab. Simulations were performed to analyze the effects of important process and cellular parameters on key measures of reactor performance including ethanol titer, ethanol-to-acetate ratio, and CO and H2 conversions. Our computational study demonstrated that mathematical modeling provides a complementary tool to experimentation for understanding, predicting, and optimizing syngas fermentation reactors. These model predictions could guide future cellular and process engineering efforts aimed at alleviating bottlenecks to biochemical production in syngas bubble column reactors.

  3. Bubble column fermenter modeling: a comparison for pressure effects

    Energy Technology Data Exchange (ETDEWEB)

    Shioya, S; Dang, N D.P.; Dunn, I J

    1978-01-01

    Two models which describe the oxygen transfer, oxygen uptake, and axial mixing in a bubble column fermenter are described. Model I includes no pressure effects and can be solved analytically. Model II incorporates the influence of hydrostatic pressure on oxygen solubility and gas expansion and must be solved numerically. The liquid phase oxygen concentration profiles from both models are compared to ascertain for what parametric conditions and for what maximum column height Model I is valid. Results show that for many situations Model I can approximate the oxygen profiles in a 10 m column within 20%. As the transfer and uptake rates increase, the deviation of Model I can reach 80% for a 10 m column. 7 figures.

  4. Hydrodynamics of Bubble Columns: Turbulence and Population Balance Model

    Directory of Open Access Journals (Sweden)

    Camila Braga Vieira

    2018-03-01

    Full Text Available This paper presents an in-depth numerical analysis on the hydrodynamics of a bubble column. As in previous works on the subject, the focus here is on three important parameters characterizing the flow: interfacial forces, turbulence and inlet superficial Gas Velocity (UG. The bubble size distribution is taken into account by the use of the Quadrature Method of Moments (QMOM model in a two-phase Euler-Euler approach using the open-source Computational Fluid Dynamics (CFD code OpenFOAM (Open Field Operation and Manipulation. The interfacial forces accounted for in all the simulations presented here are drag, lift and virtual mass. For the turbulence analysis in the water phase, three versions of the Reynolds Averaged Navier-Stokes (RANS k-ε turbulence model are examined: namely, the standard, modified and mixture variants. The lift force proves to be of major importance for a trustworthy prediction of the gas volume fraction profiles for all the (superficial gas velocities tested. Concerning the turbulence, the mixture k-ε model is seen to provide higher values of the turbulent kinetic energy dissipation rate in comparison to the other models, and this clearly affects the prediction of the gas volume fraction in the bulk region, and the bubble-size distribution. In general, the modified k-ε model proves to be a good compromise between modeling simplicity and accuracy in the study of bubble columns of the kind undertaken here.

  5. Bubble Column with Electrolytes: Gas Holdup and Flow Regimes

    Czech Academy of Sciences Publication Activity Database

    Orvalho, Sandra; Růžička, Marek; Drahoš, Jiří

    2009-01-01

    Roč. 48, č. 17 (2009), s. 8237-8243 ISSN 0888-5885 R&D Projects: GA ČR GA104/07/1110; GA ČR GP104/09/P255; GA AV ČR(CZ) IAA200720801; GA MŠk LA319 Institutional research plan: CEZ:AV0Z40720504 Keywords : bubble column * hydrodynamics * surfactants Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.758, year: 2009

  6. Detailed modeling of hydrodynamics mass transfer and chemical reactions in a bubble column using a discrete bubble model

    NARCIS (Netherlands)

    Darmana, D.; Deen, N.G.; Kuipers, J.A.M.

    2005-01-01

    A 3D discrete bubble model is adopted to investigate complex behavior involving hydrodynamics, mass transfer and chemical reactions in a gas¿liquid bubble column reactor. In this model a continuum description is adopted for the liquid phase and additionally each individual bubble is tracked in a

  7. Modeling of mass transfer and chemical reactions in a bubble column reactor using a discrete bubble model

    NARCIS (Netherlands)

    Darmana, D.; Deen, N.G.; Kuipers, J.A.M.

    2004-01-01

    A 3D discrete bubble model is adopted to investigate complex behavior involving hydrodynamics, mass transfer and chemical reactions in a gas-liquid bubble column reactor. In this model a continuum description is adopted for the liquid phase and additionally each individual bubble is tracked in a

  8. Detailed modeling of hydrodynamics mass transfer and chemical reactions in a bubble column using a discrete bubble model

    NARCIS (Netherlands)

    Darmana, D.; Deen, N.G.; Kuipers, J.A.M.

    2005-01-01

    A 3D discrete bubble model is adopted to investigate complex behavior involving hydrodynamics, mass transfer and chemical reactions in a gas–liquid bubble column reactor. In this model a continuum description is adopted for the liquid phase and additionally each individual bubble is tracked in a

  9. Wire-Mesh Tomography Measurements of Void Fraction in Rectangular Bubble Columns

    International Nuclear Information System (INIS)

    Reddy Vanga, B.N.; Lopez de Bertodano, M.A.; Zaruba, A.; Prasser, H.M.; Krepper, E.

    2004-01-01

    Bubble Columns are widely used in the process industry and their scale-up from laboratory scale units to industrial units have been a subject of extensive study. The void fraction distribution in the bubble column is affected by the column size, superficial velocity of the dispersed phase, height of the liquid column, size of the gas bubbles, flow regime, sparger design and geometry of the bubble column. The void fraction distribution in turn affects the interfacial momentum transfer in the bubble column. The void fraction distribution in a rectangular bubble column 10 cm wide and 2 cm deep has been measured using Wire-Mesh Tomography. Experiments were performed in an air-water system with the column operating in the dispersed bubbly flow regime. The experiments also serve the purpose of studying the performance of wire-mesh sensors in batch flows. A 'wall peak' has been observed in the measured void fraction profiles, for the higher gas flow rates. This 'wall peak' seems to be unique, as this distribution has not been previously reported in bubble column literature. Low gas flow rates yielded the conventional 'center peak' void profile. The effect of column height and superficial gas velocity on the void distribution has been investigated. Wire-mesh Tomography also facilitates the measurement of bubble size distribution in the column. This paper presents the measurement principle and the experimental results for a wide range of superficial gas velocities. (authors)

  10. Control of polymer network topology in semi-batch systems

    Science.gov (United States)

    Wang, Rui; Olsen, Bradley; Johnson, Jeremiah

    Polymer networks invariably possess topological defects: loops of different orders. Since small loops (primary loops and secondary loops) both lower the modulus of network and lead to stress concentration that causes material failure at low deformation, it is desirable to greatly reduce the loop fraction. We have shown that achieving loop fraction close to zero is extremely difficult in the batch process due to the slow decay of loop fraction with the polymer concentration and chain length. Here, we develop a modified kinetic graph theory that can model network formation reactions in semi-batch systems. We demonstrate that the loop fraction is not sensitive to the feeding policy if the reaction volume maintains constant during the network formation. However, if we initially put concentrated solution of small junction molecules in the reactor and continuously adding polymer solutions, the fractions of both primary loop and higher-order loops will be significantly reduced. There is a limiting value (nonzero) of loop fraction that can be achieved in the semi-batch system in condition of extremely slow feeding rate. This minimum loop fraction only depends on a single dimensionless variable, the product of concentration and with single chain pervaded volume, and defines an operating zone in which the loop fraction of polymer networks can be controlled through adjusting the feeding rate of the semi-batch process.

  11. COMPUTATIONAL AND EXPERIMENTAL MODELING OF SLURRY BUBBLE COLUMN REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Paul C.K. Lam; Isaac K. Gamwo; Dimitri Gidaspow

    2002-05-01

    The objective of this study was to develop a predictive experimentally verified computational fluid dynamics (CFD) model for gas-liquid-solid flow. A three dimensional transient computer code for the coupled Navier-Stokes equations for each phase was developed and is appended in this report. The principal input into the model is the viscosity of the particulate phase which was determined from a measurement of the random kinetic energy of the 800 micron glass beads and a Brookfield viscometer. The details are presented in the attached paper titled ''CFD Simulation of Flow and Turbulence in a Slurry Bubble Column''. This phase of the work is in press in a referred journal (AIChE Journal, 2002) and was presented at the Fourth International Conference on Multiphase Flow (ICMF 2001) in New Orleans, May 27-June 1, 2001 (Paper No. 909). The computed time averaged particle velocities and concentrations agree with Particle Image Velocimetry (PIV) measurements of velocities and concentrations, obtained using a combination of gamma-ray and X-ray densitometers, in a slurry bubble column, operated in the bubbly-coalesced fluidization regime with continuous flow of water. Both the experiment and the simulation show a down-flow of particles in the center of the column and up-flow near the walls and nearly uniform particle concentration. Normal and shear Reynolds stresses were constructed from the computed instantaneous particle velocities. The PIV measurement and the simulation produced instantaneous particle velocities. The PIV measurement and the simulation produced similar nearly flat horizontal profiles of turbulent kinetic energy of particles. To better understand turbulence we studied fluidization in a liquid-solid bed. This work was also presented at the Fourth International Conference on Multiphase Flow (ICMF 2001, Paper No. 910). To understand turbulence in risers, measurements were done in the IIT riser with 530 micron glass beads using a PIV

  12. An algorithm for predicting the hydrodynamic and mass transfer parameters in bubble column and slurry bubble column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lemoine, Romain; Behkish, Arsam; Sehabiague, Laurent; Heintz, Yannick J.; Morsi, Badie I. [Chemical and Petroleum Engineering Department, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Oukaci, Rachid [Energy Technology Partners, Pittsburgh, PA 15238 (United States)

    2008-04-15

    A large number of experimental data points obtained in our laboratory as well as from the literature, covering wide ranges of reactor geometry (column diameter, gas distributor type/open area), physicochemical properties (liquid and gas densities and molecular weights, liquid viscosity and surface tension, gas diffusivity, solid particles size/density), and operating variables (superficial gas velocity, temperature and pressure, solid loading, impurities concentration, mixtures) were used to develop empirical as well as Back-Propagation Neural Network (BPNN) correlations in order to predict the hydrodynamic and mass transfer parameters in bubble column reactors (BCRs) and slurry bubble column reactors (SBCRs). The empirical and BPNN correlations developed were incorporated in an algorithm for predicting gas holdups ({epsilon}{sub G}, {epsilon}{sub G-Small}, {epsilon}{sub G-Large}); volumetric liquid-side mass transfer coefficients (k{sub L}a, k{sub L}a{sub -Small,} k{sub L}a{sub -Large}); Sauter mean bubble diameters (d{sub S}, d{sub S-Small}, d{sub S-Large}){sub ;} gas-liquid interfacial areas (a, a{sub Small}, a{sub Large}); and liquid-side mass transfer coefficients (k{sub L}, k{sub L-Large}, k{sub L-Small}) for total, small and large gas bubbles in BCRs and SBCRs. The developed algorithm was used to predict the effects of reactor diameter and solid (alumina) loading on the hydrodynamic and mass transfer parameters in the Fisher-Tropsch (F-T) synthesis for the hydrogenation of carbon monoxide in a SBCR, and to predict the effects of presence of organic impurities (which decrease the liquid surface tension) and air superficial mass velocity in the Loprox process for the wet air oxidation of organic pollutants in a BCR. In the F-T process, the predictions showed that increasing the reactor diameter from 0.1 to 7.0 m and/or increasing the alumina loading from 25 to 50 wt.% significantly decreased {epsilon}{sub G,} k{sub L}a{sub H2} and k{sub L}a{sub CO} and

  13. Influence of drag closures and inlet conditions on bubble dynamics and flow behavior inside a bubble column

    Directory of Open Access Journals (Sweden)

    Amjad Asad

    2017-01-01

    Full Text Available In this paper, the hydrodynamics of a bubble column is investigated numerically using the discrete bubble model, which tracks the dispersed bubbles individually in a liquid column. The discrete bubble model is combined with the volume of fluid approach to account for a proper free surface boundary condition at the liquid–gas interface. This improves describing the backflow region, which takes place close to the wall region. The numerical simulation is conducted by means of the open source computational fluid dynamics library OpenFOAM®. In order to validate the numerical model, experimental results of a bubble column are used. The numerical prediction shows an overall good agreement compared to the experimental data. The effect of injection conditions and the influence of the drag closures on bubble dynamics are investigated in the current paper. Here, the significant effect of injection boundary conditions on bubble dynamics and flow velocity in the studied cavity is revealed. Moreover, the impact of the choice of the drag closure on the liquid velocity field and on bubble behavior is indicated by comparing three drag closures derived from former studies.

  14. Determination of size distribution of bubbles in a bubbly column two phase flows by ultrasound and neural networks

    International Nuclear Information System (INIS)

    Baroni, Douglas B.; Lamy, Carlos A.; Bittencourt, Marcelo S.Q.; Pereira, Claudio M.N.A.; Cunha Filho, Jurandyr S.; Motta, Mauricio S.

    2011-01-01

    The development of advanced nuclear reactor conceptions depends largely on the amount of available data to the designer. Non invasive ultrasonic techniques can contribute to the evaluation of gas-liquid two-phase regimes in the nuclear thermo-hydraulic circuits. A key-point for success of those techniques is the interpretation of the ultrasonic signal. In this work, a methodology based in artificial neural networks (ANN) is proposed to predict size distribution of bubbles in a bubbly flow. To accomplish that, an air feed system control was used to obtain specific bubbly flows in an experimental system utilizing a Plexiglas vertical bubbly column. Four different size distribution of bubbles were generated. The bubbles were photographed and measured. To evaluate the different size distribution of bubbles it was used the ultrasonic reflected echo on the opposite wall of the column. Then, an ANN has been developed for predicting size distribution of bubbles by using the frequency spectra of the ultrasonic signal as input. A trained artificial neural network using ultrasonic signal in the frequency domain can evaluate with a good precision the size distribution of bubbles generated in this system. (author)

  15. Determination of size distribution of bubbles in a bubbly column two phase flows by ultrasound and neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Baroni, Douglas B.; Lamy, Carlos A.; Bittencourt, Marcelo S.Q.; Pereira, Claudio M.N.A., E-mail: douglasbaroni@ien.gov.b, E-mail: lamy@ien.gov.b, E-mail: bittenc@ien.gov.b, E-mail: cmnap@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Cunha Filho, Jurandyr S. [Escola Tecnica Estadual Visconde de Maua (ETEVM/RJ), Rio de Janeiro, RJ (Brazil); Motta, Mauricio S., E-mail: mmotta@cefet-rj.b [Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca (CEFET/RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    The development of advanced nuclear reactor conceptions depends largely on the amount of available data to the designer. Non invasive ultrasonic techniques can contribute to the evaluation of gas-liquid two-phase regimes in the nuclear thermo-hydraulic circuits. A key-point for success of those techniques is the interpretation of the ultrasonic signal. In this work, a methodology based in artificial neural networks (ANN) is proposed to predict size distribution of bubbles in a bubbly flow. To accomplish that, an air feed system control was used to obtain specific bubbly flows in an experimental system utilizing a Plexiglas vertical bubbly column. Four different size distribution of bubbles were generated. The bubbles were photographed and measured. To evaluate the different size distribution of bubbles it was used the ultrasonic reflected echo on the opposite wall of the column. Then, an ANN has been developed for predicting size distribution of bubbles by using the frequency spectra of the ultrasonic signal as input. A trained artificial neural network using ultrasonic signal in the frequency domain can evaluate with a good precision the size distribution of bubbles generated in this system. (author)

  16. The energy balance within a bubble column evaporator

    Science.gov (United States)

    Fan, Chao; Shahid, Muhammad; Pashley, Richard M.

    2018-05-01

    Bubble column evaporator (BCE) systems have been studied and developed for many applications, such as thermal desalination, sterilization, evaporative cooling and controlled precipitation. The heat supplied from warm/hot dry bubbles is to vaporize the water in various salt solutions until the solution temperature reaches steady state, which was derived into the energy balance of the BCE. The energy balance and utilization involved in each BCE process form the fundamental theory of these applications. More importantly, it opened a new field for the thermodynamics study in the form of heat and vapor transfer in the bubbles. In this paper, the originally derived energy balance was reviewed on the basis of its physics in the BCE process and compared with new proposed energy balance equations in terms of obtained the enthalpy of vaporization (Δ H vap) values of salt solutions from BCE experiments. Based on the analysis of derivation and Δ H vap values comparison, it is demonstrated that the original balance equation has high accuracy and precision, within 2% over 19-55 °C using improved systems. Also, the experimental and theoretical techniques used for determining Δ H vap values of salt solutions were reviewed for the operation conditions and their accuracies compared to the literature data. The BCE method, as one of the most simple and accurate techniques, offers a novel way to determine Δ H vap values of salt solutions based on its energy balance equation, which had error less than 3%. The thermal energy required to heat the inlet gas, the energy used for water evaporation in the BCE and the energy conserved from water vapor condensation were estimated in an overall energy balance analysis. The good agreement observed between input and potential vapor condensation energy illustrates the efficiency of the BCE system. Typical energy consumption levels for thermal desalination for producing pure water using the BCE process was also analyzed for different inlet air

  17. Study of Bubble Size, Void Fraction, and Mass Transport in a Bubble Column under High Amplitude Vibration

    Directory of Open Access Journals (Sweden)

    Shahrouz Mohagheghian

    2018-04-01

    Full Text Available Vertical vibration is known to cause bubble breakup, clustering and retardation in gas-liquid systems. In a bubble column, vibration increases the mass transfer ratio by increasing the residence time and phase interfacial area through introducing kinetic buoyancy force (Bjerknes effect and bubble breakup. Previous studies have explored the effect of vibration frequency (f, but minimal effort has focused on the effect of amplitude (A on mass transfer intensification. Thus, the current work experimentally examines bubble size, void fraction, and mass transfer in a bubble column under relatively high amplitude vibration (1.5 mm < A <9.5 mm over a frequency range of 7.5–22.5 Hz. Results of the present work were compared with past studies. The maximum stable bubble size under vibration was scaled using Hinze theory for breakage. Results of this work indicate that vibration frequency exhibits local maxima in both mass transfer and void fraction. Moreover, an optimum amplitude that is independent of vibration frequency was found for mass transfer enhancements. Finally, this work suggests physics-based models to predict void fraction and mass transfer in a vibrating bubble column.

  18. Production of cellulase and xylanase in a bubble gum column using immobilized Aspergillus niger KKS

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seong-Woo; Kim, Seung-Woo [Univ. of Suwon (Korea, Republic of); Lee, Jin-Suk [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    1995-05-01

    Aspergillus niger KKS, isolated from a farmland near Suwon, was immobilized on Celite and polyurethane foams. Enzyme activities produced by the immobilized cell system in a bubble column were higher than that of shake-flask culture. The enzyme productivities were twice as high. {Beta}-Glucosidase, {Beta}-xylosidase, and xylanase activities obtained in a bubble column were significant when the ground rice straw was used as a substrate. 9 refs., 2 figs., 3 tabs.

  19. Numerical simulation of the dynamic flow behaviour in a bubble column: comparison of the bubble-induced turbulence models in K-epsilon model

    NARCIS (Netherlands)

    Zhang, D.; Deen, N.G.; Kuipers, J.A.M.

    2005-01-01

    Numerical simulations of the gas-liquid bubbly flow in a bubble column were conducted with the commercial CFD package CFX-4.4 to investigate the performance of three models (Pfleger and Becker, 2001; Sato and Sekoguchi, 1975; Troshko and Hassan, 2001) to account for the bubble-induced turbulence in

  20. Visualisation of air–water bubbly column flow using array Ultrasonic Velocity Profiler

    Directory of Open Access Journals (Sweden)

    Munkhbat Batsaikhan

    2017-11-01

    Full Text Available In the present work, an experimental study of bubbly two-phase flow in a rectangular bubble column was performed using two ultrasonic array sensors, which can measure the instantaneous velocity of gas bubbles on multiple measurement lines. After the sound pressure distribution of sensors had been evaluated with a needle hydrophone technique, the array sensors were applied to two-phase bubble column. To assess the accuracy of the measurement system with array sensors for one and two-dimensional velocity, a simultaneous measurement was performed with an optical measurement technique called particle image velocimetry (PIV. Experimental results showed that accuracy of the measurement system with array sensors is under 10% for one-dimensional velocity profile measurement compared with PIV technique. The accuracy of the system was estimated to be under 20% along the mean flow direction in the case of two-dimensional vector mapping.

  1. CFD simulation of alleviation of fluid back mixing by baffles in bubble column

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Y.K.; Peng, F.F.; Wolfe, E. [Sedgman LLC, Pittsburgh, PA (United States)

    2006-07-15

    The global back mixing of liquid in an open flotation column is harmful to mineral separations. The inclusion of baffles and packing in open columns can dampen the effects of global back mixing. A mathematical model based on the principle of fluid dynamics is helpful in designing baffled or packed columns. This paper presents a two-dimensional Euler-Lagrangian model to simulate the multiphase flow for some cases of baffled and packed columns. Fluid motion is calculated by directly solving the Navier-Stokes equations by a SIMPLE approach. Bubbles are moved in a Lagrangian frame through the interaction forces imposed by the gas-fluid coupling. The simulated results successfully reveal that the liquid back-mixing effect in the open bubble columns can be alleviated by baffles or packings.

  2. A Study of CO2 Absorption Using Jet Bubble Column

    Directory of Open Access Journals (Sweden)

    Setiadi Setiadi

    2010-10-01

    Full Text Available The phenomenon of plunging jet gas-liquid contact occurs quite often in nature, it's momentum carries small air bubbles with it into the reactor medium. The momentum of the liquid stream can be sufficient to carry small bubbles completely to the bottom of the vessel. A stream of liquid falling toward a level surface of that liquid will pull the surrounding air along with it. It will indent the surface of the liquid to form a trumpet-like shape. If the velocity of the stream is high enough, air bubbles will be pulled down, i.e. entrained into the liquid. This happens for two main reasons: air that is trapped between the edge of the falling stream and the trumpet-shaped surface profile and is carried below the surface. This study investigates the potential of a vertical liquid plunging jet for a pollutant contained gas absorption technique. The absorber consists of liquid jet and gas bubble dispersed phase. The effects of operating variables such as liquid flowrate, nozzle diameter, separator pressure, etc. on gas entrainment and holdup were investigated. The mass transfer of the system is governed by the hydrodynamics of the system. Therefore a clear and precise understanding of the above is necessary : to characterize liquid and gas flow within the system, 2. Variation in velocity of the jet with the use of different nozzle diameters and flow rates, 3. Relationship between the liquid and entrained airflow rate, 4. Gas entrainment rate and gas void fraction.

  3. COMPUTATIONAL AND EXPERIMENTAL MODELING OF THREE-PHASE SLURRY-BUBBLE COLUMN REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Isaac K. Gamwo; Dimitri Gidaspow

    1999-09-01

    Considerable progress has been achieved in understanding three-phase reactors from the point of view of kinetic theory. In a paper in press for publication in Chemical Engineering Science (Wu and Gidaspow, 1999) we have obtained a complete numerical solution of bubble column reactors. In view of the complexity of the simulation a better understanding of the processes using simplified analytical solutions is required. Such analytical solutions are presented in the attached paper, Large Scale Oscillations or Gravity Waves in Risers and Bubbling Beds. This paper presents analytical solutions for bubbling frequencies and standing wave flow patterns. The flow patterns in operating slurry bubble column reactors are not optimum. They involve upflow in the center and downflow at the walls. It may be possible to control flow patterns by proper redistribution of heat exchangers in slurry bubble column reactors. We also believe that the catalyst size in operating slurry bubble column reactors is not optimum. To obtain an optimum size we are following up on the observation of George Cody of Exxon who reported a maximum granular temperature (random particle kinetic energy) for a particle size of 90 microns. The attached paper, Turbulence of Particles in a CFB and Slurry Bubble Columns Using Kinetic Theory, supports George Cody's observations. However, our explanation for the existence of the maximum in granular temperature differs from that proposed by George Cody. Further computer simulations and experiments involving measurements of granular temperature are needed to obtain a sound theoretical explanation for the possible existence of an optimum catalyst size.

  4. Characterizing fluid dynamics in a bubble column aimed for the determination of reactive mass transfer

    Science.gov (United States)

    Kováts, Péter; Thévenin, Dominique; Zähringer, Katharina

    2018-02-01

    Bubble column reactors are multiphase reactors that are used in many process engineering applications. In these reactors a gas phase comes into contact with a fluid phase to initiate or support reactions. The transport process from the gas to the liquid phase is often the limiting factor. Characterizing this process is therefore essential for the optimization of multiphase reactors. For a better understanding of the transfer mechanisms and subsequent chemical reactions, a laboratory-scale bubble column reactor was investigated. First, to characterize the flow field in the reactor, two different methods have been applied. The shadowgraphy technique is used for the characterisation of the bubbles (bubble diameter, velocity, shape or position) for various process conditions. This technique is based on particle recognition with backlight illumination, combined with particle tracking velocimetry (PTV). The bubble trajectories in the column can also be obtained in this manner. Secondly, the liquid phase flow has been analysed by particle image velocimetry (PIV). The combination of both methods, delivering relevant information concerning disperse (bubbles) and continuous (liquid) phases, leads to a complete fluid dynamical characterization of the reactor, which is the pre-condition for the analysis of mass transfer between both phases.

  5. Monte Carlo simulation on kinetics of batch and semi-batch free radical polymerization

    KAUST Repository

    Shao, Jing; Tang, Wei; Xia, Ru; Feng, Xiaoshuang; Chen, Peng; Qian, Jiasheng; Song, Changjiang

    2015-01-01

    experimental and simulation studies, we showed the capability of our Monte Carlo scheme on representing polymerization kinetics in batch and semi-batch processes. Various kinetics information, such as instant monomer conversion, molecular weight

  6. Global and Local Hydrodynamics of Bubble Columns – Effect of Gas Distributor.

    Czech Academy of Sciences Publication Activity Database

    Sharaf, S.; Zedníková, Mária; Růžička, Marek; Azzopardi, B.J.

    2016-01-01

    Roč. 288, MAR 15 (2016), s. 489-504 ISSN 1385-8947 R&D Projects: GA MŠk(CZ) LD13018 Grant - others:EPSRC(GB) EP/F016050/1 Institutional support: RVO:67985858 Keywords : bubble columns * wire mesh sensor * void fraction Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 6.216, year: 2016

  7. Hydrodynamics and mass transfer in slurry bubble columns : scale and pressure effects

    NARCIS (Netherlands)

    Chilekar, V.P.

    2007-01-01

    Slurry bubble columns (SBC) are widely used in the chemical industry as a multiphase reactor. Applications include oxidation and hydrogenation reactions, fermentation, Fischer-Tropsch synthesis, and waste water treatment. The advantages of a SBC over other multiphase reactors are the simple

  8. ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS (SBCR)

    Energy Technology Data Exchange (ETDEWEB)

    M.H. Al-Dahhan; M.P. Dudukovic; L.S. Fan

    2001-07-25

    This report summarizes the accomplishment made during the second year of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals. The technical difficulties that were encountered in implementing Computer Automated Radioactive Particle Tracking (CARPT) in high pressure SBCR have been successfully resolved. New strategies for data acquisition and calibration procedure have been implemented. These have been performed as a part of other projects supported by Industrial Consortium and DOE via contract DE-2295PC95051 which are executed in parallel with this grant. CARPT and Computed Tomography (CT) experiments have been performed using air-water-glass beads in 6 inch high pressure stainless steel slurry bubble column reactor at selected conditions. Data processing of this work is in progress. The overall gas holdup and the hydrodynamic parameters are measured by Laser Doppler Anemometry (LDA) in 2 inch slurry bubble column using Norpar 15 that mimic at room temperature the Fischer Tropsch wax at FT reaction conditions of high pressure and temperature. To improve the design and scale-up of bubble column, new correlations have been developed to predict the radial gas holdup and the time averaged axial liquid recirculation velocity profiles in bubble columns.

  9. Study on bubble column humidification and dehumidification system for coal mine wastewater treatment.

    Science.gov (United States)

    Gao, Penghui; Zhang, Meng; Du, Yuji; Cheng, Bo; Zhang, Donghai

    2018-04-01

    Water is important resource for human survival and development. Coal mine wastewater (CMW) is a byproduct of the process of coal mining, which is about 7.0 × 10 10 m 3 in China in 2016. Considering coal mine wastewater includes different ingredients, a new bubble column humidification and dehumidification system is proposed for CMW treatment. The system is mainly composed of a bubble column humidification and dehumidification unit, solar collector, fan and water tank, in which air is used as a circulating medium. The system can avoid water treatment component blocking for reverse osmosis (RO) and multi effect distillation (MED) dealing with CMW, and produce water greenly. By analysis of heat and mass transfer, the effects of solar radiation, air bubble velocity and mine water temperature on water treatment production characteristics are studied. Compared with other methods, thermal energy consumption (TEC) of bubble column humidification and dehumidification (BCHD) is moderate, which is about 700 kJ/kg (powered by solar energy). The results would provide a new method for CMW treatment and insights into the efficient coal wastewater treatment, besides, it helps to identify the parameters for the technology development in mine water treatment.

  10. Design and calculation of tritium extraction from liquid LiPb by bubble columns for ITER

    International Nuclear Information System (INIS)

    Xie, Bo

    2009-04-01

    A mathematical model describing the complex fluid-dynamics of a bubble extractor from liquid LiPb loop for ITER is presented. A parametric analysis of the extraction efficiency of a bubble column as a function of the process parameters is carried out and the design of a bubble extractor system is proposed. On this base, a mathematical model is built by taking into consideration the kinetics of deuterium desorption from liquid LiPb alloy. The calculation data of deuterium release-behavior from liquid LiPb under different operating conditions of temperature and deuterium partial pressures and helium gas flow-rates in the liquid LiPb alloy are obtained. These results have shown that the overall re- lease process is governed by the diffusion of deuterium atoms in the LiPb and by the heterogeneous reaction at the gas-eutectic interface of the deuterium atoms recombination under the probable working temperature range. (authors)

  11. A novel closed system bubble column photobioreactor for detailed characterisation of micro and macroalgal growth

    DEFF Research Database (Denmark)

    Holdt, Susan Løvstad; Christensen, L.; Iversen, J. J.L.

    produced oxygen was catalytically removed from the closed system by addition of hydrogen over a palladium catalyst to avoid photorespiration and to quantify oxygen production. In addition, the bubble column photobioreactor was well suited for cultivation of algae due to fast gas to liquid mass transfer (k...... in the different batch cultures of both micro and macroalgae. The algal SGR is normally considered to be constant. The maximum SGRs found by on-line determination were 0.13 hr-1 for T. striata and 0.12 d-1 for C. crispus. During batch cultivation growth stoichiometry was determined and photosynthetic quotients......Growth of the marine microalgae Tetraselmis striata Butcher and macroalgae Chondrus crispus Stackhouse was investigated in batch cultures in a closed system bubble column photobioreactor. A laboratory cultivation system was constructed that allowed on-line monitoring of temperature, p...

  12. Technical Note: Detection of gas bubble leakage via correlation of water column multibeam images

    Science.gov (United States)

    Schneider von Deimling, J.; Papenberg, C.

    2012-03-01

    Hydroacoustic detection of natural gas release from the seafloor has been conducted in the past by using singlebeam echosounders. In contrast, modern multibeam swath mapping systems allow much wider coverage, higher resolution, and offer 3-D spatial correlation. Up to the present, the extremely high data rate hampers water column backscatter investigations and more sophisticated visualization and processing techniques are needed. Here, we present water column backscatter data acquired with a 50 kHz prototype multibeam system over a period of 75 seconds. Display types are of swath-images as well as of a "re-sorted" singlebeam presentation. Thus, individual and/or groups of gas bubbles rising from the 24 m deep seafloor clearly emerge in the acoustic images, making it possible to estimate rise velocities. A sophisticated processing scheme is introduced to identify those rising gas bubbles in the hydroacoustic data. We apply a cross-correlation technique adapted from particle imaging velocimetry (PIV) to the acoustic backscatter images. Temporal and spatial drift patterns of the bubbles are assessed and are shown to match very well to measured and theoretical rise patterns. The application of this processing to our field data gives clear results with respect to unambiguous bubble detection and remote bubble rise velocimetry. The method can identify and exclude the main source of misinterpretations, i.e. fish-mediated echoes. Although image-based cross-correlation techniques are well known in the field of fluid mechanics for high resolution and non-inversive current flow field analysis, we present the first application of this technique as an acoustic bubble detector.

  13. Technical Note: Detection of gas bubble leakage via correlation of water column multibeam images

    Directory of Open Access Journals (Sweden)

    J. Schneider von Deimling

    2012-03-01

    Full Text Available Hydroacoustic detection of natural gas release from the seafloor has been conducted in the past by using singlebeam echosounders. In contrast, modern multibeam swath mapping systems allow much wider coverage, higher resolution, and offer 3-D spatial correlation. Up to the present, the extremely high data rate hampers water column backscatter investigations and more sophisticated visualization and processing techniques are needed. Here, we present water column backscatter data acquired with a 50 kHz prototype multibeam system over a period of 75 seconds. Display types are of swath-images as well as of a "re-sorted" singlebeam presentation. Thus, individual and/or groups of gas bubbles rising from the 24 m deep seafloor clearly emerge in the acoustic images, making it possible to estimate rise velocities. A sophisticated processing scheme is introduced to identify those rising gas bubbles in the hydroacoustic data. We apply a cross-correlation technique adapted from particle imaging velocimetry (PIV to the acoustic backscatter images. Temporal and spatial drift patterns of the bubbles are assessed and are shown to match very well to measured and theoretical rise patterns. The application of this processing to our field data gives clear results with respect to unambiguous bubble detection and remote bubble rise velocimetry. The method can identify and exclude the main source of misinterpretations, i.e. fish-mediated echoes. Although image-based cross-correlation techniques are well known in the field of fluid mechanics for high resolution and non-inversive current flow field analysis, we present the first application of this technique as an acoustic bubble detector.

  14. Characteristics of Gas-liquid Mass Transfer and Interfacial Area in a Bubble Column

    International Nuclear Information System (INIS)

    Lim, Dae Ho; Yoo, Dong Jun; Kang, Yong

    2015-01-01

    Characteristics of gas-liquid mass transfer and interfacial area were investigated in a bubble column of diameter and height of 0.102 m and 2.5 m, respectively. Effects of gas and liquid velocities on the volumetric gas-liquid mass transfer coefficient (k L a), interfacial area (a) and liquid side true mass transfer coefficient (k L ) were examined. The interfacial area and volumetric gas-liquid mass transfer coefficient were determined directly by adopting the simultaneous physical desorption of O 2 and chemical absorption of CO 2 in the column. The values of k L a and a increased with increasing gas velocity but decreased with increasing liquid velocity in the bubble column which was operated in the churn turbulent flow regime. The value of k L increased with increasing gas velocity but did not change considerably with increasing liquid velocity. The liquid side mass transfer was found to be related closely to the liquid circulation as well as the effective contacting frequency between the bubbles and liquid phases

  15. Characteristics of Gas-liquid Mass Transfer and Interfacial Area in a Bubble Column

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Dae Ho; Yoo, Dong Jun; Kang, Yong [Chungnam National University, Daejeon (Korea, Republic of)

    2015-02-15

    Characteristics of gas-liquid mass transfer and interfacial area were investigated in a bubble column of diameter and height of 0.102 m and 2.5 m, respectively. Effects of gas and liquid velocities on the volumetric gas-liquid mass transfer coefficient (k{sub L}a), interfacial area (a) and liquid side true mass transfer coefficient (k{sub L}) were examined. The interfacial area and volumetric gas-liquid mass transfer coefficient were determined directly by adopting the simultaneous physical desorption of O{sub 2} and chemical absorption of CO{sub 2} in the column. The values of k{sub L}a and a increased with increasing gas velocity but decreased with increasing liquid velocity in the bubble column which was operated in the churn turbulent flow regime. The value of k{sub L} increased with increasing gas velocity but did not change considerably with increasing liquid velocity. The liquid side mass transfer was found to be related closely to the liquid circulation as well as the effective contacting frequency between the bubbles and liquid phases.

  16. Bubble column and CFD simulation for chemical recycling of polyethylene terephthalate

    Science.gov (United States)

    Alzuhairi, Mohammed

    2018-05-01

    Computational Fluid Dynamics (CFD) is an important simulation tool, which uses powerful computer to get optimal design in industrial processes. New approach technique of bubble column for three phases has been used with respect to chemical recycling of Polyethylene Terephthalate (PET). The porous ceramic has been used in thin plate (5 mm) with a narrow pore size distribution. Excellent agreement between CFD has been predicted and experimental profiles of hold-up and velocity close to wall have been observed for a column diameter 0.08 m, column height 0.15 m (HD), and superficial gas velocity (VG) 0.05 m/s. The main purpose of the current study is to highlight depolymerization of PET chemically by using the close system of Ethylene Glycol, PET-Catalyzed, and Nitrogen glycolysis process in bubble column of three phases technique by using Nano catalyst, SiO2 with various weight percent (0.01, 0.02, 0.05, 0.1, 0.2, and 0.5) based on PET weight and preheated Nitrogen up to 100° C by extra heater in bubble column reactor. The depolymerization time could be reduced in order to improve heat and mass transfer in comparison with the traditional methods. Little amount not exceeding 0.01% of Nano SiO2 is enough for completing depolymerization. The final product of PET depolymerization has full characterization by FTIR, AFM, CHN tests and has been used as a vital additive for Bitumen, it has been investigated as a moisture-proof, water seepage-proof material, and as a tough resistant to environmental conditions.

  17. ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS(SBCR)

    Energy Technology Data Exchange (ETDEWEB)

    M.H. Al-Dahhan; L.S. Fan; M.P. Dudukovic

    2002-07-25

    This report summarizes the accomplishment made during the third year of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals. Data processing of the performed Computer Automated Radioactive Particle Tracking (CARPT) experiments in 6 inch column using air-water-glass beads (150 {micro}m) system has been completed. Experimental investigation of time averaged three phases distribution in air-Therminol LT-glass beads (150 {micro}m) system in 6 inch column has been executed. Data processing and analysis of all the performed Computed Tomography (CT) experiments have been completed, using the newly proposed CT/Overall gas holdup methodology. The hydrodynamics of air-Norpar 15-glass beads (150 {micro}m) have been investigated in 2 inch slurry bubble column using Dynamic Gas Disengagement (DGD), Pressure Drop fluctuations, and Fiber Optic Probe. To improve the design and scale-up of bubble column reactors, a correlation for overall gas holdup has been proposed based on Artificial Neural Network and Dimensional Analysis.

  18. An investigation into a laboratory scale bubble column humidification dehumidification desalination system powered by biomass energy

    International Nuclear Information System (INIS)

    Rajaseenivasan, T.; Srithar, K.

    2017-01-01

    Highlights: • A biomass based humidification dehumidification desalination system is tested. • System is analyzed with the direct and preheated air supply. • Highest distillate rate of 6.1 kg/h is collected with the preheated air supply. • The minimum fuel feed of 0.2 kg is needed to produce 1 kg of fresh water. - Abstract: This article describes a biomass powered bubble column humidification-dehumidification desalination system. This system mainly consists of a biomass stove, air heat exchanger, bubble column humidifier and dehumidifier. Saw dust briquettes are used as biomass fuel in the stove. First level of experiments are carried out in bubble column humidifier with ambient air supply to select the best water depth, bubble pipe hole diameter and water temperature. Experiments are conducted by integrating the humidifier with the dehumidifier. Air is sent to the humidifier with and without pre-heating. Preheating of air is carried out in the air heat exchanger by using the flue gas and flame from the combustion chamber. It is observed that the humidifier ability is augmented with the rise in water depth, water temperature, mass flow rate of air and cooling water flow rate, and reduction in bubble pipe hole diameter. It is found from Taguchi analysis that the water temperature dominates in controlling the humidifier performance compared to other parameters. Better specific humidity is recorded with a bubble pipe hole diameter of 1 mm, water depth of 170 mm and water temperature of 60 °C. Highest distillate of 6.1 kg/h and 3.5 kg/h is collected for the HDH desalination system with preheated air and direct air supply respectively. Recovery of waste heat using an air heat exchanger reduces the fuel consumption from 0.36 kg to 0.2 kg for producing 1 kg of distilled water. Lowest distilled water cost of 0.0133 US $/kg through preheated air supply and 0.0231 US $/kg through direct air supply is observed. A correlation is developed to estimate the mass transfer

  19. Monte Carlo simulation on kinetics of batch and semi-batch free radical polymerization

    KAUST Repository

    Shao, Jing

    2015-10-27

    Based on Monte Carlo simulation technology, we proposed a hybrid routine which combines reaction mechanism together with coarse-grained molecular simulation to study the kinetics of free radical polymerization. By comparing with previous experimental and simulation studies, we showed the capability of our Monte Carlo scheme on representing polymerization kinetics in batch and semi-batch processes. Various kinetics information, such as instant monomer conversion, molecular weight, and polydispersity etc. are readily calculated from Monte Carlo simulation. The kinetic constants such as polymerization rate k p is determined in the simulation without of “steady-state” hypothesis. We explored the mechanism for the variation of polymerization kinetics those observed in previous studies, as well as polymerization-induced phase separation. Our Monte Carlo simulation scheme is versatile on studying polymerization kinetics in batch and semi-batch processes.

  20. Hydrodynamic effects of air sparging on hollow fiber membranes in a bubble column reactor.

    Science.gov (United States)

    Xia, Lijun; Law, Adrian Wing-Keung; Fane, Anthony G

    2013-07-01

    Air sparging is now a standard approach to reduce concentration polarization and fouling of membrane modules in membrane bioreactors (MBRs). The hydrodynamic shear stresses, bubble-induced turbulence and cross flows scour the membrane surfaces and help reduce the deposit of foulants onto the membrane surface. However, the detailed quantitative knowledge on the effect of air sparging remains lacking in the literature due to the complex hydrodynamics generated by the gas-liquid flows. To date, there is no valid model that describes the relationship between the membrane fouling performance and the flow hydrodynamics. The present study aims to examine the impact of hydrodynamics induced by air sparging on the membrane fouling mitigation in a quantitative manner. A modelled hollow fiber module was placed in a cylindrical bubble column reactor at different axial heights with the trans-membrane pressure (TMP) monitored under constant flux conditions. The configuration of bubble column without the membrane module immersed was identical to that studied by Gan et al. (2011) using Phase Doppler Anemometry (PDA), to ensure a good quantitative understanding of turbulent flow conditions along the column height. The experimental results showed that the meandering flow regime which exhibits high flow instability at the 0.3 m is more beneficial to fouling alleviation compared with the steady flow circulation regime at the 0.6 m. The filtration tests also confirmed the existence of an optimal superficial air velocity beyond which a further increase is of no significant benefit on the membrane fouling reduction. In addition, the alternate aeration provided by two air stones mounted at the opposite end of the diameter of the bubble column was also studied to investigate the associated flow dynamics and its influence on the membrane filtration performance. It was found that with a proper switching interval and membrane module orientation, the membrane fouling can be effectively

  1. Biofiltration of Air/Styrene and Air/Styrene/Acetone mixtures in a bubble column reactor

    OpenAIRE

    Vieira, Ana

    2009-01-01

    The goal of this work was the treatment of polluted waste gases in a bubble column reactor (BCR), in order to determinate the maximum value of reactor’s efficiency (RE), varying the inlet concentration (C in) of the pollutants. The gaseous mixtures studied were: (i) air with styrene and (ii) air with styrene and acetone. The liquid phase used to contain the biomass in the reactor was a basal salt medium (BSM), fundamental for the microorganisms’ development. The reactor used in this pro...

  2. Flow patterns in a slurry-bubble-column reactor under reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    Toselane, B.A.; Brown, D.M.; Zou, B.S.; Dudukovic, M.P. [Washington Univ., St. Louis, MO (United States)

    1995-12-31

    The gas and liquid radioactive tracer response curves obtained in an industrial bubble column reactor of height to diameter ratio of 10 are analyzed and the suitability of the axial dispersion model for interpretation of the results is discussed. The relationship between the tracer concentration distribution and measured detector response of the soluble gas tracer (Ar-41) is possibly dominated by the dissolved gas. The one dimensional axial dispersion model cannot match all the experimental observations well and the flow pattern of the undissolved gas cannot be determined with certainty.

  3. Parameterized data-driven fuzzy model based optimal control of a semi-batch reactor.

    Science.gov (United States)

    Kamesh, Reddi; Rani, K Yamuna

    2016-09-01

    A parameterized data-driven fuzzy (PDDF) model structure is proposed for semi-batch processes, and its application for optimal control is illustrated. The orthonormally parameterized input trajectories, initial states and process parameters are the inputs to the model, which predicts the output trajectories in terms of Fourier coefficients. Fuzzy rules are formulated based on the signs of a linear data-driven model, while the defuzzification step incorporates a linear regression model to shift the domain from input to output domain. The fuzzy model is employed to formulate an optimal control problem for single rate as well as multi-rate systems. Simulation study on a multivariable semi-batch reactor system reveals that the proposed PDDF modeling approach is capable of capturing the nonlinear and time-varying behavior inherent in the semi-batch system fairly accurately, and the results of operating trajectory optimization using the proposed model are found to be comparable to the results obtained using the exact first principles model, and are also found to be comparable to or better than parameterized data-driven artificial neural network model based optimization results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Prediction of gas hold-up for alcohol solutions in a draft-tube bubble column

    Directory of Open Access Journals (Sweden)

    Albijanić Boris V.

    2006-01-01

    Full Text Available This paper deals with the prediction of the overall gas hold-up (εg, in the diluted solutions of C -C alcohols in draft - tube bubble column, by applying several newly proposed correlations and some of the well-known equations. Experiments were carried out in a column, consisting of two coaxial glass tubes, with a single sparger. Gas phase was air, while the liquid phases were aqueous solutions of alcohols, in concentrations of 0.5% w/w and 1% w/w. Overall gas hold-up was determined by applying volume expansion technique. The following order for εg values was observed: water < methanol < ethanol < n-propanol < n-butanol. Concentration of the applied alcohol appeared to be less significant than the .sort of alcohol itself. The best newly proposed correlation enables predicting of our experimental data with the average square deviation of empirical formula: s2=0.58 E-04.

  5. Two-Phase Flow in Packed Columns and Generation of Bubbly Suspensions for Chemical Processing in Space

    Science.gov (United States)

    Motil, Brian J.; Green, R. D.; Nahra, H. K.; Sridhar, K. R.

    2000-01-01

    For long-duration space missions, the life support and In-Situ Resource Utilization (ISRU) systems necessary to lower the mass and volume of consumables carried from Earth will require more sophisticated chemical processing technologies involving gas-liquid two-phase flows. This paper discusses some preliminary two-phase flow work in packed columns and generation of bubbly suspensions, two types of flow systems that can exist in a number of chemical processing devices. The experimental hardware for a co-current flow, packed column operated in two ground-based low gravity facilities (two-second drop tower and KC- 135 low-gravity aircraft) is described. The preliminary results of this experimental work are discussed. The flow regimes observed and the conditions under which these flow regimes occur are compared with the available co-current packed column experimental work performed in normal gravity. For bubbly suspensions, the experimental hardware for generation of uniformly sized bubbles in Couette flow in microgravity conditions is described. Experimental work was performed on a number of bubbler designs, and the capillary bubble tube was found to produce the most consistent size bubbles. Low air flow rates and low Couette flow produce consistent 2-3 mm bubbles, the size of interest for the "Behavior of Rapidly Sheared Bubbly Suspension" flight experiment. Finally the mass transfer implications of these two-phase flows is qualitatively discussed.

  6. Theoretical modelling and optimization of bubble column dehumidifier for a solar driven humidification-dehumidification system

    Science.gov (United States)

    Ranjitha, P. Raj; Ratheesh, R.; Jayakumar, J. S.; Balakrishnan, Shankar

    2018-02-01

    Availability and utilization of energy and water are the top most global challenges being faced by the new millennium. At the present state water scarcity has become a global as well as a regional challenge. 40 % of world population faces water shortage. Challenge of water scarcity can be tackled only with increase in water supply beyond what is obtained from hydrological cycle. This can be achieved either by desalinating the sea water or by reusing the waste water. High energy requirement need to be overcome for either of the two processes. Of many desalination technologies, humidification dehumidification (HDH) technology powered by solar energy is widely accepted for small scale production. Detailed optimization studies on system have the potential to effectively utilize the solar energy for brackish water desalination. Dehumidification technology, specifically, require further study because the dehumidifier effectiveness control the energetic performance of the entire HDH system. The reason attributes to the high resistance involved to diffuse dilute vapor through air in a dehumidifier. The present work intends to optimize the design of a bubble column dehumidifier for a solar energy driven desalination process. Optimization is carried out using Matlab simulation. Design process will identify the unique needs of a bubble column dehumidifier in HDH system.

  7. Ozonation kinetics of winery wastewater in a pilot-scale bubble column reactor.

    Science.gov (United States)

    Lucas, Marco S; Peres, José A; Lan, Bing Yan; Li Puma, Gianluca

    2009-04-01

    The degradation of organic substances present in winery wastewater was studied in a pilot-scale, bubble column ozonation reactor. A steady reduction of chemical oxygen demand (COD) was observed under the action of ozone at the natural pH of the wastewater (pH 4). At alkaline and neutral pH the degradation rate was accelerated by the formation of radical species from the decomposition of ozone. Furthermore, the reaction of hydrogen peroxide (formed from natural organic matter in the wastewater) and ozone enhances the oxidation capacity of the ozonation process. The monitoring of pH, redox potential (ORP), UV absorbance (254 nm), polyphenol content and ozone consumption was correlated with the oxidation of the organic species in the water. The ozonation of winery wastewater in the bubble column was analysed in terms of a mole balance coupled with ozonation kinetics modeled by the two-film theory of mass transfer and chemical reaction. It was determined that the ozonation reaction can develop both in and across different kinetic regimes: fast, moderate and slow, depending on the experimental conditions. The dynamic change of the rate coefficient estimated by the model was correlated with changes in the water composition and oxidant species.

  8. A bubble column evaporator with basic flat-plate condenser for brackish and seawater desalination.

    Science.gov (United States)

    Schmack, Mario; Ho, Goen; Anda, Martin

    2016-01-01

    This paper describes the development and experimental evaluation of a novel bubble column-based humidification-dehumidification system, for small-scale desalination of saline groundwater or seawater in remote regions. A bubble evaporator prototype was built and matched with a simple flat-plate type condenser for concept assessment. Consistent bubble evaporation rates of between 80 and 88 ml per hour were demonstrated. Particular focus was on the performance of the simple condenser prototype, manufactured from rectangular polyvinylchlorid plastic pipe and copper sheet, a material with a high thermal conductivity that quickly allows for conduction of the heat energy. Under laboratory conditions, a long narrow condenser model of 1500 mm length and 100 mm width achieved condensate recovery rates of around 73%, without the need for external cooling. The condenser prototype was assessed under a range of different physical conditions, that is, external water cooling, partial insulation and aspects of air circulation, via implementing an internal honeycomb screen structure. Estimated by extrapolation, an up-scaled bubble desalination system with a 1 m2 condenser may produce around 19 l of distilled water per day. Sodium chloride salt removal was found to be highly effective with condensate salt concentrations between 70 and 135 µS. Based on findings and with the intent to reduce material cost of the system, a shorter condenser length of 750 mm for the non-cooled (passive) condenser and of 500 mm for the water-cooled condenser was considered to be equally efficient as the experimentally evaluated prototype of 1500 mm length.

  9. PROGRESS TOWARDS MODELING OF FISCHER TROPSCH SYNTHESIS IN A SLURRY BUBBLE COLUMN REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Tami Grimmett; Anastasia M. Gandrik; Steven P. Antal

    2010-11-01

    The Hybrid Energy Systems Testing (HYTEST) Laboratory is being established at the Idaho National Laboratory to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. A central component of the HYTEST is the slurry bubble column reactor (SBCR) in which the gas-to-liquid reactions will be performed to synthesize transportation fuels using the Fischer Tropsch (FT) process. SBCRs are cylindrical vessels in which gaseous reactants (for example, synthesis gas or syngas) is sparged into a slurry of liquid reaction products and finely dispersed catalyst particles. The catalyst particles are suspended in the slurry by the rising gas bubbles and serve to promote the chemical reaction that converts syngas to a spectrum of longer chain hydrocarbon products, which can be upgraded to gasoline, diesel or jet fuel. These SBCRs operate in the churn-turbulent flow regime which is characterized by complex hydrodynamics, coupled with reacting flow chemistry and heat transfer, that effect reactor performance. The purpose of this work is to develop a computational multiphase fluid dynamic (CMFD) model to aid in understanding the physico-chemical processes occurring in the SBCR. Our team is developing a robust methodology to couple reaction kinetics and mass transfer into a four-field model (consisting of the bulk liquid, small bubbles, large bubbles and solid catalyst particles) that includes twelve species: (1) CO reactant, (2) H2 reactant, (3) hydrocarbon product, and (4) H2O product in small bubbles, large bubbles, and the bulk fluid. Properties of the hydrocarbon product were specified by vapor liquid equilibrium calculations. The absorption and kinetic models, specifically changes in species concentrations, have been incorporated into the mass continuity equation. The reaction rate is determined based on the macrokinetic model for a cobalt catalyst developed by Yates and Satterfield [1]. The

  10. Bubbles

    DEFF Research Database (Denmark)

    Dholakia, Nikhilesh; Turcan, Romeo V.

    2013-01-01

    A goal of our ongoing research stream is to develop a multidisciplinary metatheory of bubbles. In this viewpoint paper we put forward a typology of bubbles by comparing four types of assets – entertainment, commodities, financial securities (stocks), and housing properties – where bubbles could...... and do form occasionally. Cutting across and comparing such varied asset types provides some rich insights into the nature of bubbles – and offers an inductive way to arrive at the typology of bubbles....

  11. A Quadrature Method of Moments for Polydisperse Flow in Bubble Columns Including Poly-Celerity, Breakup and Coalescence

    Directory of Open Access Journals (Sweden)

    Thomas Acher

    2014-12-01

    Full Text Available A simulation model for 3D polydisperse bubble column flows in an Eulerian/Eulerian framework is presented. A computationally efficient and numerically stable algorithm is created by making use of quadrature method of moments (QMOM functionalities, in conjunction with appropriate breakup and coalescence models. To account for size dependent bubble motion, the constituent moments of the bubble size distribution function are transported with individual velocities. Validation of the simulation results against experimental and numerical data of Hansen [1] show the capability of the present model to accurately predict complex gas-liquid flows.

  12. Cadmium removal using Cladophora in batch, semi-batch and flow reactors.

    Science.gov (United States)

    Sternberg, Steven P K; Dorn, Ryan W

    2002-02-01

    This study presents the results of using viable algae to remove cadmium from a synthetic wastewater. In batch and semi-batch tests, a local strain of Cladophora algae removed 80-94% of the cadmium introduced. The flow experiments that followed were conducted using non-local Cladophora parriaudii. Results showed that the alga removed only 12.7(+/-6.4)% of the cadmium introduced into the reactor. Limited removal was the result of insufficient algal quantities and poor contact between the algae and cadmium solution.

  13. A novel closed system bubble column photobioreactor for detailed characterisation of micro- and macroalgal growth

    DEFF Research Database (Denmark)

    Holdt, Susan Løvstad; Christensen, L.; Iversen, J. J. L.

    2014-01-01

    was suited for cultivation of algae due to fast gas-to-liquid mass transfer (kLa) and fast mixing provided by split and dual sparging. Specific growth rates (SGRs) were measured using both offline and online measurements. The latter was possible, because rectilinear correlation was observed between carbon......Growth of the marine microalga Tetraselmis striata Butcher and the macroalga Chondrus crispus Stackhouse was investigated in batch cultures in a closed system bubble column photobioreactor. A laboratory cultivation system was constructed that allowed online monitoring of pH and dissolved oxygen...... changes in growth with up to three different SGRs in the different batch cultures of both micro- and macroalgae. The maximum SGRs found by online determination were 0.13 h-1 for T. striata and 0.12 day-1 for C. crispus. We have developed and described a system and presented some data handling tools...

  14. Biomass Production Chlorella Vulgaris Buitenzorg Using Series of Bubble Column Photo Bioreactor with a Periodic Illumination

    Directory of Open Access Journals (Sweden)

    Anondho Wijanarko

    2010-10-01

    Full Text Available Chlorella vulgaris Buitenzorg cultivation using three bubble column photo bioreactors arranged in series with a volume of 200 mL for 130 hours shows an increase of biomass production of Chlorella vulgaris Buitenzorg up to 1.20 times and a decrease of the ability of CO2 fixation compared to single reactor at a periodic sun illumination cycle. The operation conditions on cultivation are as following: T, 29.0oC; P,1 atm.; UG, 2.40 m/h; CO2, 10%; Benneck medium; and illumination source by Phillip Halogen Lamp 20W /12V/ 50Hz. Other research parameters such as microbial carbon dioxide transferred rate (qco2, CO2 transferred rate (CTR, energy consumption for cellular formation (Ex, and cultural bicarbonate species concentration [HCO3] also give better results on series of reactor.

  15. Numerical investigation of a bubble-column photo-bioreactor design for biodiesel production from microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Seo, I.H.; Lee, I.B.; Hwang, H.S.; Hong, S.W.; Bitog, J.P.; Kwon, K.S.; Choi, J.S.; Song, S.H. [Seoul National Univ., Seoul (Korea, Democratic People' s Republic of). Dept. of Rural Systems Engineering and Research Inst. for Agriculture and Life Sciences

    2010-07-01

    Biodiesel made from vegetable oil is among the most desirable of renewable energy sources because it can be a substitute for diesel oil. However, biodiesel from soybean or corn can be confronted with a food crisis. Microalgae is a new biodiesel source which contains high oil lipids with a high growth rate, and which also offers value-added products from the residue, such as cosmetics, health functional food or pharmaceuticals. Microalgae are best cultivated in photo-bioreactors (PBRs) where light, nutrients, carbon dioxide and temperature can be controlled. Despite the current availability of PBRs, only a few can be practically used for mass production. Computational fluid dynamics (CFD) was used in this study to design an optimum bubble-column PBR for mass production of microalgae. Multi-phase models including bubble movement, meshes and time step independent tests were considered to develop the 3-dimensional CFD model. Particle Image Velocimetry (PIV) tests were used to enhance and validate the model. Different types of PBRs were simulated and compared quantitatively with the microalgae's growth model.

  16. CFD simulation of fatty acid methyl ester production in bubble column reactor

    Science.gov (United States)

    Salleh, N. S. Mohd; Nasir, N. F.

    2017-09-01

    Non-catalytic transesterification is one of the method that was used to produce the fatty acid methyl ester (FAME) by blowing superheated methanol bubbles continuously into the vegetable oil without using any catalyst. This research aimed to simulate the production of FAME from palm oil in a bubble column reactor. Computational Fluid Dynamic (CFD) simulation was used to predict the distribution of fatty acid methyl ester and other product in the reactor. The fluid flow and component of concentration along the reaction time was investigated and the effects of reaction temperature (523 K and 563 K) on the non-catalytic transesterification process has been examined. The study was carried out using ANSYS CFX 17.1. The finding from the study shows that increasing the temperature leads to higher amount of fatty acid methyl ester can be produced in shorter time. On the other hand, concentration of the component such as triglyceride (TG), glycerol (GL) and fatty acid methyl ester (FAME) can be known when reaching the optimum condition.

  17. Experimental Study of the Flooding and Appearance of a Bubble Bed on Top of a Countercurrent Packed-Bed Column

    Czech Academy of Sciences Publication Activity Database

    Jiřičný, Vladimír; Staněk, Vladimír; Svoboda, Petr; Ondráček, Jakub

    2001-01-01

    Roč. 40, č. 1 (2001), s. 407-412 ISSN 0888-5885 R&D Projects: GA ČR GA203/97/1174 Institutional research plan: CEZ:AV0Z4072921 Keywords : appearance * bubble-bed * packed bed column Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.351, year: 2001

  18. Determining the Enthalpy of Vaporization of Salt Solutions Using the Cooling Effect of a Bubble Column Evaporator

    Science.gov (United States)

    Fan, Chao; Pashley, Richard M.

    2016-01-01

    The enthalpy of vaporization (?H[subscript vap]) of salt solutions is not easily measured, as a certain quantity of pure water has to be evaporated from a solution, at constant composition, and at a fixed temperature and pressure; then the corresponding heat input has to be measured. However, a simple bubble column evaporator (BCE) was used as a…

  19. Numerical modeling of carbon dioxide chemisorption in sodium hydroxide solution in a micro-structured bubble column

    NARCIS (Netherlands)

    Jain, D.; Kuipers, J.A.M.; Deen, N.G.

    2015-01-01

    Gas-liquid flows with solid catalyst particles are encountered in many applications in the chemical, petrochemical, and pharmaceutical industries. Most commonly, two reactor types, slurry bubble column (SBC) and trickle bed (TB) reactors are applied for large scale in the industry. Both of these

  20. Crystal agglomeration of europium oxalate in reaction crystallization using double-jet semi-batch reactor

    International Nuclear Information System (INIS)

    Kim, Woo-Sik; Kim, Woon-Soo; Kim, Kwang-Seok; Kim, Joon-Soo; Ward, Michael D.

    2004-01-01

    The particle agglomeration of europium oxalate was investigated in a double-jet semi-batch reactor over a wide range of operating variables, including the agitation speed, reactant feed rate, and reactant concentration. The size of the agglomerates was directly dictated by the particle collision and supersaturation promoting agglomeration and the fluid shear force inhibiting agglomeration. Thus, with a longer feeding time and higher feed concentration for the reaction crystallization, the mean particle size increased, while the corresponding total particle population decreased due to the enhanced chance of particle agglomeration, resulting from a longer residence time and higher supersaturation in the reactor. Agitation was found to exhibit a rather complicated influence on particle agglomeration. Although both particle collision and turbulent fluid shear were promoted by an increase in the mixing intensity, the crystal agglomeration of europium oxalate was maximized at around 500 rpm of agitation speed due to an optimized balance between particle aggregation and breakage

  1. Application of the Fenton's process in a bubble column reactor for hydroquinone degradation.

    Science.gov (United States)

    Lima, Vanessa N; Rodrigues, Carmen S D; Madeira, Luis M

    2017-11-27

    The aim of this study was to assess the degradation and mineralization of hydroquinone (HQ) by the Fenton's process in a bubble column reactor (BCR). The effect of the main operating variables, namely, air flow rate, effluent volume, hydrogen peroxide (H 2 O 2 ) concentration, catalyst (Fe 2+ ) dose, initial pH, and temperature, were assessed. For all air flow rates tested, no concentration gradients along the column were noticed, evidencing that a good mixing was reached in the BCR. For the best conditions tested ([H 2 O 2 ] = 500 mg/L, [Fe 2+ ] = 45 mg/L, T = 24 °C, Q air  = 2.5 mL/min, pH = 3.0, and V = 5 L), complete HQ degradation was reached, with ~ 39% of total organic carbon (TOC) removal, and an efficiency of the oxidant use-η H2O2 -of 0.39 (ratio between TOC removed per H 2 O 2 consumed normalized by the theoretical stoichiometric value); moreover, a non-toxic effluent was generated. Under these conditions, the intermediates and final oxidation compounds identified and quantified were a few carboxylic acids, namely, maleic, pyruvic, and oxalic. As a strategy to improve the TOC removal, a gradual dosage of the optimal H 2 O 2 concentration was implemented, being obtained ~ 55% of mineralization (with complete HQ degradation). Finally, the matrix effect was evaluated, for which a real wastewater was spiked with 100 mg/L of HQ; no reduction in terms of HQ degradation and mineralization was observed compared to the solution in distilled water.

  2. Improvement of ore recovery efficiency in a flotation column cell using ultra-sonic enhanced bubbles

    Science.gov (United States)

    Filippov, L. O.; Royer, J. J.; Filippova, I. V.

    2017-07-01

    The ore process flotation technique is enhanced by using external ultra-sonic waves. Compared to the classical flotation method, the application of ultrasounds to flotation fluids generates micro-bubbles by hydrodynamic cavitation. Flotation performances increase was modelled as a result of increased probabilities of the particle-bubble attachment and reduced detachment probability under sonication. A simplified analytical Navier-Stokes model is used to predict the effect of ultrasonic waves on bubble behavior. If the theory is verified by experimentation, it predicts that the ultrasonic waves would create cavitation micro-bubbles, smaller than the flotation bubble added by the gas sparger. This effect leads to increasing the number of small bubbles in the liquid which promote particle-bubble attachment through coalescence between bubbles and micro-bubbles. The decrease in the radius of the flotation bubbles under external vibration forces has an additional effect by enhancing the bubble-particle collision. Preliminary results performed on a potash ore seem to confirm the theory.

  3. Detailed modelling of hydrodynamics, mass transfer and chemical reactions in a bubble column using a discrete bubble model: Chemisorption of CO2 into NaOH solution, numerical and experimental study

    NARCIS (Netherlands)

    Darmana, D.; Henket, R.L.B.; Deen, N.G.; Kuipers, J.A.M.

    2007-01-01

    This paper describes simulations that were performed with an Euler–Lagrange model that takes into account mass transfer and chemical reaction reported by Darmana et al. (2005. Detailed modelling of hydrodynamics, mass transfer and chemical reactions in a bubble column using a discrete bubble model.

  4. Comparative analysis of top-lit bubble column and gas-lift bioreactors for microalgae-sourced biodiesel production

    International Nuclear Information System (INIS)

    Seyed Hosseini, Nekoo; Shang, Helen; Ross, Gregory M.; Scott, John Ashley

    2016-01-01

    Highlights: • Top-lit gas-lift and bubble columns were studied as deep algal cultivation tank. • A theoretical energy requirement analysis and a hydrodynamic model were developed. • Areal productivities of both bioreactors were notably higher than traditional raceways. • A gas-lift reactor sparged with 6% carbon dioxide achieved the highest lipid production. • Hydrodynamic and light stresses increased the lipid content suitable for biodiesel. - Abstract: The development of top-lit one-meter deep bioreactors operated as either a gas-lift or bubble column system using air and carbon dioxide enriched air was studied. The goal was high productivity cultivation of algae with elevated lipid levels suitable for conversion into biodiesel. A theoretical energy requirement analysis and a hydrodynamic model were developed to predict liquid circulation velocities in the gas-lift bioreactor, which agreed well with experimental measurements. The influence of operational parameters such as design of bioreactor, gas flow rates and carbon dioxide concentration on the growth and lipid volumetric production of Scenedesmus dimorphus was evaluated using factorial design. While biomass productivity was 12% higher in the bubble column bioreactor (68.2 g_d_w m"−"2 day"−"1), maximum lipid volumetric production (0.19 g_L_i_p_i_d L"−"1) was found in a gas-lift bioreactor sparged with 6% carbon dioxide due to hydrodynamic and light stresses.

  5. CFD simulation of flow pattern in a bubble column reactor for forming aerobic granules and its development.

    Science.gov (United States)

    Fan, Wenwen; Yuan, LinJiang; Li, Yonglin

    2018-06-04

    The flow pattern is considered to play an important role in the formation of aerobic granular sludge in a bubble column reactor; therefore, it is necessary to understand the behavior of the flow in the reactor. A three-dimensional computational fluid dynamics (CFD) simulation for bubble column reactor was established to visualize the flow patterns of two-phase air-liquid flow and three-phase air-liquid-sludge flow under different ratios of height to diameter (H/D ratio) and superficial gas upflow velocities (SGVs). Moreover, a simulation of the three-phase flow pattern at the same SGV and different characteristics of the sludge was performed in this study. The results show that not only SGV but also properties of sludge involve the transformation of flow behaviors and relative velocity between liquid and sludge. For the original activated sludge floc to cultivate aerobic granules, the flow pattern has nothing to do with sludge, but is influenced by SGV, and the vortices is occurred and the relative velocity is increased with an increase in SGV; the two-phase flow can simplify the three-phase flow that predicts the flow pattern development in bubble column reactor (BCR) for aerobic granulation. For the aerobic granules, the liquid flow behavior developed from the symmetrical circular flow to numbers and small-size vortices with an increase in the sludge diameter, the relative velocity is amount up to u r =5.0, it is 29.4 times of original floc sludge.

  6. The Effects of the Properties of Gases on the Design of Bubble Columns Equipped with a Fine Pore Sparger

    Directory of Open Access Journals (Sweden)

    Athanasios G. Kanaris

    2018-03-01

    Full Text Available This work concerns the performance of bubble columns equipped with porous sparger and investigates the effect of gas phase properties by conducting experiments with various gases (i.e., air, CO2, He that cover a wide range of physical property values. The purpose is to investigate the validity of the design equations, which were proposed in our previous work and can predict with reasonable accuracy the transition point from homogeneous to heterogeneous regime as well as the gas holdup and the mean Sauter diameter at the homogeneous regime. Although, the correlations were checked with data obtained using different geometrical configurations and several Newtonian and non-Newtonian liquids, as well as the addition of surfactants, the gas phase was always atmospheric air. The new experiments revealed that only the use of low-density gas (He has a measurable effect on bubble column performance. More precisely, when the low-density gas (He is employed, the transition point shifts to higher gas flow rates and the gas holdup decreases, a fact attributed to the lower momentum force exerted by the gas. In view of the new data, the proposed correlations have been slightly modified to include the effect of gas phase properties and it is found that they can predict the aforementioned quantities with an accuracy of ±15%. It has been also proved that computational fluid dynamics (CFD simulations are an accurate means for assessing the flow characteristics inside a bubble column.

  7. An Eulerian-Eulerian Approach to CFD Simulation of Two-Phase Bubble Column using ANSYS CFX Code

    International Nuclear Information System (INIS)

    Mohd Amirul Syafiq Mohd Yunos; Nur Khairunnisa Abd Halim; Siti Aslina Hussain

    2016-01-01

    Bubble columns are widely used as gas-liquid contactors and reactors in chemical, biochemical and petrochemical industries. Effective mixing, high interfacial area between phases, cheap to install and lack of moving parts are the main factors bubble column is chosen for the described processes. Understanding the complexity of the fluid dynamics of gas-liquid flow in bubble column is important due to its unsteady complex processes as well as application in the chemical and bioprocess industries. The gas-liquid of two-phase fluid flow system has been carried out to investigate the hydrodynamics parameters. An Eulerian-Eulerian approach was used to model air as the dispersed phase within a continuous phase of water using the commercial software ANSYSTM CFD software (CFX 14.0). The turbulence in the gas-liquid simulation is described by using the k-e model. This process occurs under the atmospheric pressure. The configuration of model consists of 0.2 m width, 0.2 m depth and 0.5 m height of rectangular bubble column equipped with a sparger at the bottom. Two different sparger designs, Sparger A with 4 holes and 2.6 mm diameter each and Sparger B with 81 holes and 0.5 mm diameter each are tested for three different value of superficial gas velocity of 0.0125 m/s, 0.0501 m/s and 0.0627 m/s. The volume fraction of model is described the behavior of bubble which is represented by the parameters of gas holdup, contact surface area and gas superficial velocity. The simulation was verified by comparing the two different model results. Comparison of simulation results with the experimental work data has provided a successful validation of the model. Results shows the contact surface area increasing with behavior of bubble and gas holdup increases with increasing superficial gas velocity but independent of the sparger design at high superficial velocity (>0.05 m/s). The highest value obtained which is represented of water superficial velocity, gas holdup and superficial gas

  8. Non-catalytic alcoholysis process for production of biodiesel fuel by using bubble column reactor

    Science.gov (United States)

    Hagiwara, S.; Nabetani, H.; Nakajima, M.

    2015-04-01

    -edible lipids by use of the SMV reactor has not been examined yet. Therefore, this study aims to investigate the productivity of biodiesel produced from waste vegetable oils using the SMV reactor. Biodiesel fuel is a replacement for diesel as a fuel produced from biomass resources. It is generally produced as a FAME derived from vegetable oil by using alkaline catalyzed alcoholysis process. This alkaline method requires deacidification process prior to the reaction process and the alkaline catalyst removal process after the reaction. Those process increases the total cost of biodiesel fuel production. In order to solve the problems in the conventional alkaline catalyzed alcoholysis process, the authors proposed a non-catalytic alcoholysis process called the Superheated Methanol Vapor (SMV) method with bubble column reactor. So, this study aims to investigate the productivity of biodiesel produced from vegetable oils and other lipids using the SMV method with bubble column reactor.

  9. Non-catalytic alcoholysis process for production of biodiesel fuel by using bubble column reactor

    International Nuclear Information System (INIS)

    Hagiwara, S; Nabetani, H; Nakajima, M

    2015-01-01

    -edible lipids by use of the SMV reactor has not been examined yet. Therefore, this study aims to investigate the productivity of biodiesel produced from waste vegetable oils using the SMV reactor. Biodiesel fuel is a replacement for diesel as a fuel produced from biomass resources. It is generally produced as a FAME derived from vegetable oil by using alkaline catalyzed alcoholysis process. This alkaline method requires deacidification process prior to the reaction process and the alkaline catalyst removal process after the reaction. Those process increases the total cost of biodiesel fuel production. In order to solve the problems in the conventional alkaline catalyzed alcoholysis process, the authors proposed a non-catalytic alcoholysis process called the Superheated Methanol Vapor (SMV) method with bubble column reactor. So, this study aims to investigate the productivity of biodiesel produced from vegetable oils and other lipids using the SMV method with bubble column reactor

  10. p-Nitrophenol degradation by Fenton's oxidation in a bubble column reactor.

    Science.gov (United States)

    Rodrigues, Carmen S D; Borges, Ricardo A C; Lima, Vanessa N; Madeira, Luis M

    2018-01-15

    This paper reports on a study of the oxidation of p-nitrophenol (PNP) in a bubble column reactor (BCR). The use of the air stream aimed to provide perfect mixing in the liquid phase, which was successfully achieved and checked experimentally; there were no concentration gradients along the column, even at the lowest air flow rate used (Q = 1 mL/min at room temperature and atmospheric pressure). The effect of the operating variables was assessed, and a total reduction of PNP was reached, as well as mineralization of 49.2%, oxidant consumption of 90.3%, and with an efficiency of use - η H2O2 - of 0.09 mg C/mg H 2 O 2 , under the best operating conditions found - Q = 1 mL/min, [H 2 O 2 ] = 1.6 g/L, [Fe 2+ ] = 80 mg/L, pH = 3.0 and T = 22-24 °C - (after 120 min of reaction). Following this, various strategies were developed for improving the mineralization rate; it was found that the addition of H 2 O 2 every 5 min and readjusting the pH after 30 min of reaction allow the attainment of a much higher TOC removal (75.1%) and efficiency of oxidant use (η H2O2  = 0.17 mg C/mg H 2 O 2 ) with less oxidant. A reaction mechanism was proposed, based on intermediates identified that include p-nitrocatechol - PNC, p-benzoquinone - PB, hydroquinone - HQ - and carboxylic acids (oxalic, maleic and fumaric). Since the performance achieved in the BCR was good, and very similar to that obtained in a conventional batch reactor, it was possible to verify the efficacy of carrying out the Fenton process in this reactor configuration, which in our future work will focus on the treatability of industrial effluents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. ANALYSIS OF TRICKLE BED AND PACKED BUBBLE COLUMN BIOREACTORS FOR COMBINED CARBON OXIDATION AND NITRIFICATION

    Directory of Open Access Journals (Sweden)

    Iliuta I.

    2002-01-01

    Full Text Available Biological removal of nitrogen and carbon by combined nitrification-oxidation in gas-liquid trickle-bed reactors (TBRs and packed bubble columns (PBCs was analyzed theoretically using a transient two-dimensional model. The model describes TBR and PBC performances at steady state as well as their transient response to a pulse or step increase in inlet methanol and NH4+-nitrogen concentrations. The hydrodynamic parameters were determined from residence time distribution measurements, using an imperfect pulse method for time-domain analysis of nonideal pulse tracer response. A transient diffusion model of the tracer in the porous particle coupled with the piston-dispersion-exchange model was used to interpret the residence time distribution curves obtained. Gas-liquid mass transfer parameters were determined by a stationary method based on the least-squares fit of the calculated concentration profiles in gas phase to the experimental values. Analysis of steady-state performances showed that under like operating conditions, the TBR outperforms the PBC in terms of conversions. A pulse change in the inlet methanol or NH4+-nitrogen concentration causes a negligible transient change in the outlet methanol concentration and a negligible or high transient change in the outlet NH4+-nitrogen concentration. A step change in the inlet methanol concentration causes the negligible transient change in the methanol outlet concentration and a relatively important transient change in the NH4+-nitrogen outlet concentration. A step increase in the NH4+-nitrogen inlet concentration induces a drastic transient change in the NH4+-nitrogen outlet concentration but a negligible transient change in the methanol outlet concentration.

  12. Quantifying Methane Flux from a Prominent Seafloor Crater with Water Column Imagery Filtering and Bubble Quantification Techniques

    Science.gov (United States)

    Mitchell, G. A.; Gharib, J. J.; Doolittle, D. F.

    2015-12-01

    Methane gas flux from the seafloor to atmosphere is an important variable for global carbon cycle and climate models, yet is poorly constrained. Methodologies used to estimate seafloor gas flux commonly employ a combination of acoustic and optical techniques. These techniques often use hull-mounted multibeam echosounders (MBES) to quickly ensonify large volumes of the water column for acoustic backscatter anomalies indicative of gas bubble plumes. Detection of these water column anomalies with a MBES provides information on the lateral distribution of the plumes, the midwater dimensions of the plumes, and their positions on the seafloor. Seafloor plume locations are targeted for visual investigations using a remotely operated vehicle (ROV) to determine bubble emission rates, venting behaviors, bubble sizes, and ascent velocities. Once these variables are measured in-situ, an extrapolation of gas flux is made over the survey area using the number of remotely-mapped flares. This methodology was applied to a geophysical survey conducted in 2013 over a large seafloor crater that developed in response to an oil well blowout in 1983 offshore Papua New Guinea. The site was investigated by multibeam and sidescan mapping, sub-bottom profiling, 2-D high-resolution multi-channel seismic reflection, and ROV video and coring operations. Numerous water column plumes were detected in the data suggesting vigorously active vents within and near the seafloor crater (Figure 1). This study uses dual-frequency MBES datasets (Reson 7125, 200/400 kHz) and ROV video imagery of the active hydrocarbon seeps to estimate total gas flux from the crater. Plumes of bubbles were extracted from the water column data using threshold filtering techniques. Analysis of video images of the seep emission sites within the crater provided estimates on bubble size, expulsion frequency, and ascent velocity. The average gas flux characteristics made from ROV video observations is extrapolated over the number

  13. Energy efficiency of batch and semi-batch (CCRO) reverse osmosis desalination.

    Science.gov (United States)

    Warsinger, David M; Tow, Emily W; Nayar, Kishor G; Maswadeh, Laith A; Lienhard V, John H

    2016-12-01

    As reverse osmosis (RO) desalination capacity increases worldwide, the need to reduce its specific energy consumption becomes more urgent. In addition to the incremental changes attainable with improved components such as membranes and pumps, more significant reduction of energy consumption can be achieved through time-varying RO processes including semi-batch processes such as closed-circuit reverse osmosis (CCRO) and fully-batch processes that have not yet been commercialized or modelled in detail. In this study, numerical models of the energy consumption of batch RO (BRO), CCRO, and the standard continuous RO process are detailed. Two new energy-efficient configurations of batch RO are analyzed. Batch systems use significantly less energy than continuous RO over a wide range of recovery ratios and source water salinities. Relative to continuous RO, models predict that CCRO and batch RO demonstrate up to 37% and 64% energy savings, respectively, for brackish water desalination at high water recovery. For batch RO and CCRO, the primary reductions in energy use stem from atmospheric pressure brine discharge and reduced streamwise variation in driving pressure. Fully-batch systems further reduce energy consumption by not mixing streams of different concentrations, which CCRO does. These results demonstrate that time-varying processes can significantly raise RO energy efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Perancangan Sistem Pengukuran pH dan Temperatur Pada Bioreaktor Anaerob Tipe Semi-Batch

    Directory of Open Access Journals (Sweden)

    Dimas Prasetyo Oetomo

    2013-12-01

    Full Text Available Proses pada bioreaktor dapat dilakukan secara aerob yaitu menggunakan bantuan oksigen dan anaerob yaitu tidak menggunakan bantuan oksigen. Pada penelitian ini dilakukan fermentasi  enceng gondok untuk menghasilkan biogas menggunakan bioreaktor anaerob tipe semi-batch. Enceng gondok memiliki rasio C/N sebesar 22.5 – 35.84% yang merupakan komposisi optimum untuk ekstraksi biogas. Kinerja dari bioreaktor dalam produksi biogas dipengaruhi oleh beberapa parameter seperti pH dan temperatur. Pada penelitian ini dilakukan perancangan sistem pengukuran besaran pH dan temperatur secara online sehingga memudahkan dalam pengambilan data. Bahan yang digunakan pada proses fermentasi adalah campuran enceng gondok yang telah dicincang dan dicampur air dengan dua komposisi penambahan berbeda untuk dibandingkan. Pada Bioreaktor1 digunakan komposisi enceng gondok dan air sebesar 1:3 dan pada bioreaktor 2 digunakan komposisi enceng gondok dan air sebesar 0,75: 1,25. Hasil penelitian menyebutkan bahwa bioreaktor 2 dengan komposisi enceng gondok dan air sebesar 0,75: 1,25 menghasilkan biogas lebih aktif dibandingkan dengan bioreaktor 1 dengan komposisi enceng gondok dan air sebesar 1 : 3. Hal tersebut diketahui dari hasil pengukuran selama 76 hari. Dari hasil pengukuran juga diketahui bahwa penurunan nilai COD pada bioreaktor 2 lebih besar dari pada  bioreaktor 1.

  15. DEVELOPMENT OF A COMPUTATIONAL MULTIPHASE FLOW MODEL FOR FISCHER TROPSCH SYNTHESIS IN A SLURRY BUBBLE COLUMN REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Tami Grimmett; Anastasia M. Gribik; Steven P. Antal

    2011-12-01

    The Hybrid Energy Systems Testing (HYTEST) Laboratory at the Idaho National Laboratory was established to develop and test hybrid energy systems with the principal objective of reducing dependence on imported fossil fuels. A central component of the HYTEST is the slurry bubble column reactor (SBCR) in which the gas-to-liquid reactions are performed to synthesize transportation fuels using the Fischer Tropsch (FT) process. These SBCRs operate in the churn-turbulent flow regime, which is characterized by complex hydrodynamics, coupled with reacting flow chemistry and heat transfer. Our team is developing a research tool to aid in understanding the physicochemical processes occurring in the SBCR. A robust methodology to couple reaction kinetics and mass transfer into a four-field model (consisting of the bulk liquid, small bubbles, large bubbles and solid catalyst particles) consisting of thirteen species, which are CO reactant, H2 reactant, hydrocarbon product, and H2O product in small bubbles, large bubbles, and the bulk fluid plus catalyst is outlined. Mechanistic submodels for interfacial momentum transfer in the churn-turbulent flow regime are incorporated, along with bubble breakup/coalescence and two-phase turbulence submodels. The absorption and kinetic models, specifically changes in species concentrations, have been incorporated into the mass continuity equation. The reaction rate is based on the macrokinetic model for a cobalt catalyst developed by Yates and Satterfield. The model includes heat generation produced by the exothermic chemical reaction, as well as heat removal from a constant temperature heat exchanger. A property method approach is employed to incorporate vapor-liquid equilibrium (VLE) in a robust manner. Physical and thermodynamic properties as functions of changes in both pressure and temperature are obtained from VLE calculations performed external to the CMFD solver. The novelty of this approach is in its simplicity, as well as its

  16. Biodegradation of airborne acetone/styrene mixtures in a bubble column reactor.

    Science.gov (United States)

    Vanek, T; Silva, A; Halecky, M; Paca, J; Ruzickova, I; Kozliak, E; Jones, K

    2017-07-29

    The ability of a bubble column reactor (BCR) to biodegrade a mixture of styrene and acetone vapors was evaluated to determine the factors limiting the process efficiency, with a particular emphasis on the presence of degradation intermediates and oxygen levels. The results obtained under varied loadings and ratios were matched with the dissolved oxygen levels and kinetics of oxygen mass transfer, which was assessed by determination of k L a coefficients. A 1.5-L laboratory-scale BCR was operated under a constant air flow of 1.0 L.min -1 , using a defined mixed microbial population as a biocatalyst. Maximum values of elimination capacities/maximum overall specific degradation rates of 75.5 gC.m -3 .h -1 /0.197 gC.gdw -1 .h -1 , 66.0 gC.m -3 .h -1 /0.059 gC.gdw -1 .h -1 , and 45.8 gC.m -3 .h -1 /0.027 gC.gdw -1 .h -1 were observed for styrene/acetone 2:1, styrene-rich and acetone-rich mixtures, respectively, indicating significant substrate interactions and rate limitation by biological factors. The BCR removed both acetone and styrene near-quantitatively up to a relatively high organic load of 50 g.m -3 .h -1 . From this point, the removal efficiencies declined under increasing loading rates, accompanied by a significant drop in the dissolved oxygen concentration, showing a process transition to oxygen-limited conditions. However, the relatively efficient pollutant removal from air continued, due to significant oxygen mass transfer, up to a threshold loading rate when the accumulation of acetone and degradation intermediates in the aqueous medium became significant. These observations demonstrate that oxygen availability is the limiting factor for efficient pollutant degradation and that accumulation of intermediates may serve as an indicator of oxygen limitation. Microbial (activated sludge) analyses revealed the presence of amoebae and active nematodes that were not affected by variations in operational conditions.

  17. Effects of nutrient ratios and carbon dioxide bio-sequestration on biomass growth of Chlorella sp. in bubble column photobioreactor.

    Science.gov (United States)

    Vo, Hoang-Nhat-Phong; Bui, Xuan-Thanh; Nguyen, Thanh-Tin; Nguyen, Dinh Duc; Dao, Thanh-Son; Cao, Ngoc-Dan-Thanh; Vo, Thi-Kim-Quyen

    2018-08-01

    Photobioreactor technology, especially bubble column configuration, employing microalgae cultivation (e.g., Chlorella sp.), is an ideal man-made environment to achieve sufficient microalgae biomass through its strictly operational control. Nutrients, typically N and P, are necessary elements in the cultivation process, which determine biomass yield and productivity. Specifically, N:P ratios have certain effects on microalgae's biomass growth. It is also attractive that microalgae can sequester CO 2 by using that carbon source for photosynthesis and, subsequently, reducing CO 2 emission. Therefore, this study aims to investigate the effect of N:P ratios on Chlorella sp.'s growth, and to study the dynamic of CO 2 fixation in the bubble column photobioreactor. According to our results, N:P ratio of 15:1 could produce the highest biomass yield (3568 ± 158 mg L -1 ). The maximum algae concentration was 105 × 10 6  cells mL -1 , receiving after 92 h. Chlorella sp. was also able to sequester CO 2 at 28 ± 1.2%, while the specific growth rate and carbon fixation rate were observed at 0.064 h -1 and 68.9 ± 1.91 mg L -1  h -1 , respectively. The types of carbon sources (e.g., organic and inorganic carbon) possessed potential impact on microalgae's cultivation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Time-series measurements of bubble plume variability and water column methane distribution above Southern Hydrate Ridge, Oregon

    Science.gov (United States)

    Philip, Brendan T.; Denny, Alden R.; Solomon, Evan A.; Kelley, Deborah S.

    2016-03-01

    An estimated 500-2500 gigatons of methane carbon is sequestered in gas hydrate at continental margins and some of these deposits are associated with overlying methane seeps. To constrain the impact that seeps have on methane concentrations in overlying ocean waters and to characterize the bubble plumes that transport methane vertically into the ocean, water samples and time-series acoustic images were collected above Southern Hydrate Ridge (SHR), a well-studied hydrate-bearing seep site ˜90 km west of Newport, Oregon. These data were coregistered with robotic vehicle observations to determine the origin of the seeps, the plume rise heights above the seafloor, and the temporal variability in bubble emissions. Results show that the locations of seep activity and bubble release remained unchanged over the 3 year time-series investigation, however, the magnitude of gas release was highly variable on hourly time scales. Bubble plumes were detected to depths of 320-620 m below sea level (mbsl), in several cases exceeding the upper limit of hydrate stability by ˜190 m. For the first time, sustained gas release was imaged at the Pinnacle site and in-between the Pinnacle and the Summit area of venting, indicating that the subseafloor transport of fluid and gas is not restricted to the Summit at SHR, requiring a revision of fluid-flow models. Dissolved methane concentrations above background levels from 100 to 300 mbsl are consistent with long-term seep gas transport into the upper water column, which may lead to the build-up of seep-derived carbon in regional subsurface waters and to increases in associated biological activity.

  19. DEVELOPMENT OF A COMPUTATIONAL MULTIPHASE FLOW MODEL FOR FISCHER TROPSCH SYNTHESIS IN A SLURRY BUBBLE COLUMN REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Tami Grimmett; Anastasia M. Gribik; Steven P. Antal

    2010-09-01

    The Hybrid Energy Systems Testing (HYTEST) Laboratory is being established at the Idaho National Laboratory to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. A central component of the HYTEST is the slurry bubble column reactor (SBCR) in which the gas-to-liquid reactions will be performed to synthesize transportation fuels using the Fischer Tropsch (FT) process. SBCRs are cylindrical vessels in which gaseous reactants (for example, synthesis gas or syngas) is sparged into a slurry of liquid reaction products and finely dispersed catalyst particles. The catalyst particles are suspended in the slurry by the rising gas bubbles and serve to promote the chemical reaction that converts syngas to a spectrum of longer chain hydrocarbon products, which can be upgraded to gasoline, diesel or jet fuel. These SBCRs operate in the churn-turbulent flow regime which is characterized by complex hydrodynamics, coupled with reacting flow chemistry and heat transfer, that effect reactor performance. The purpose of this work is to develop a computational multiphase fluid dynamic (CMFD) model to aid in understanding the physico-chemical processes occurring in the SBCR. Our team is developing a robust methodology to couple reaction kinetics and mass transfer into a four-field model (consisting of the bulk liquid, small bubbles, large bubbles and solid catalyst particles) that includes twelve species: (1) CO reactant, (2) H2 reactant, (3) hydrocarbon product, and (4) H2O product in small bubbles, large bubbles, and the bulk fluid. Properties of the hydrocarbon product were specified by vapor liquid equilibrium calculations. The absorption and kinetic models, specifically changes in species concentrations, have been incorporated into the mass continuity equation. The reaction rate is determined based on the macrokinetic model for a cobalt catalyst developed by Yates and Satterfield [1]. The

  20. Design of slurry bubble column reactors: novel technique for optimum catalyst size selection contractual origin of the invention

    Science.gov (United States)

    Gamwo, Isaac K [Murrysville, PA; Gidaspow, Dimitri [Northbrook, IL; Jung, Jonghwun [Naperville, IL

    2009-11-17

    A method for determining optimum catalyst particle size for a gas-solid, liquid-solid, or gas-liquid-solid fluidized bed reactor such as a slurry bubble column reactor (SBCR) for converting synthesis gas into liquid fuels considers the complete granular temperature balance based on the kinetic theory of granular flow, the effect of a volumetric mass transfer coefficient between the liquid and the gas, and the water gas shift reaction. The granular temperature of the catalyst particles representing the kinetic energy of the catalyst particles is measured and the volumetric mass transfer coefficient between the gas and liquid phases is calculated using the granular temperature. Catalyst particle size is varied from 20 .mu.m to 120 .mu.m and a maximum mass transfer coefficient corresponding to optimum liquid hydrocarbon fuel production is determined. Optimum catalyst particle size for maximum methanol production in a SBCR was determined to be in the range of 60-70 .mu.m.

  1. Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage

    CSIR Research Space (South Africa)

    Mulopo, J

    2012-01-01

    Full Text Available Batch regeneration of barium carbonate (BaCO3) from barium sulphide (BaS) slurries by passing CO2 gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO3 recovery in the Alkali...

  2. Influence of cross-sectional ratio of down comer to riser on the efficiency of liquid circulation in loop air lift bubble column

    Science.gov (United States)

    Yamamoto, Tatsumi; Kawasaki, Hiroyuki; Mori, Hidetoshi

    2017-11-01

    Loop type bubble columns have good performance of liquid circulation and mass transfer by airlift effect, where the liquid circulation time is an important measurable characteristic parameter. This parameter is affected by the column construction, the aspect ratio of the column, the cross-sectional area ratio of down comer to riser (R), and the superficial gas velocity in the riser (UGR). In this work, the mean gas holdup and the liquid circulation time (TC) have been measured in four types of loop airlift type bubble column: concentric tube internal loop airlift type, rectangular internal loop airlift type, external loop airlift type, external loop airlift with separator. Air and tap water were used as gas and liquid phase, respectively. The results have demonstrated that the mean gas holdup in riser increases in proportion to UGR, and that it in downcomer changes according to the geometric parameters of each bubble column. TC has been found to conform to an empirical equation which depends on UGR and the length of draft tube or division plate in the region of 0.33 < R < 1.

  3. Experimental studies of direct contact heat transfer in a slurry bubble column at high gas temperature of a helium–water–alumina system

    International Nuclear Information System (INIS)

    Abdulrahman, M.W.

    2015-01-01

    In this paper, the direct contact heat transfer is investigated experimentally for a helium gas at 90 °C injected through a slurry of water at 22 °C and alumina solid particles in a slurry bubble column reactor. This work examines the effects of superficial gas velocity, static liquid height, solid particles concentration and solid particle size, on the volumetric heat transfer coefficient and slurry temperature of the slurry bubble column reactor. These effects are formulated in forms of empirical equations. From the experimental work, it is found that the volumetric heat transfer coefficient and the slurry temperature increase by increasing the superficial gas velocity with a higher rate of increase at lower superficial gas velocity. In addition, the volumetric heat transfer coefficient and the slurry temperature decrease by increasing the static liquid height and/or the solid concentration at any given superficial gas velocity. Furthermore, it is found that the rate of decrease of the volumetric heat transfer coefficient with the solid concentration is approximately the same for different superficial gas velocities, and the decrease of the slurry temperature with the solid concentration is negligible. - Highlights: • Direct contact heat transfer is investigated experimentally in a slurry bubble column. • Empirical equation of direct contact heat transfer Nusselt number is formulated. • The volumetric heat transfer coefficient increases with superficial gas velocity. • The volumetric heat transfer coefficient decreases with the static liquid height. • The volumetric heat transfer coefficient decreases with the solid concentration.

  4. Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage.

    Science.gov (United States)

    Mulopo, J; Zvimba, J N; Swanepoel, H; Bologo, L T; Maree, J

    2012-01-01

    Batch regeneration of barium carbonate (BaCO(3)) from barium sulphide (BaS) slurries by passing CO(2) gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO(3) recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key process parameters, such as BaS slurry concentration and CO(2) flow rate on the carbonation, as well as the extent of sulphate removal from AMD using the recovered BaCO(3) were investigated. It was observed that the carbonation reaction rate for BaCO(3) regeneration in a bubbling column reactor significantly increased with increase in carbon dioxide (CO(2)) flow rate whereas the BaS slurry content within the range 5-10% slurry content did not significantly affect the carbonation rate. The CO(2) flow rate also had an impact on the BaCO(3) morphology. The BaCO(3) recovered from the pilot-scale bubbling column reactor demonstrated effective sulphate removal ability during AMD treatment compared with commercial BaCO(3).

  5. Impact of Different H/D Ratio on Axial Gas Holdup Measured by Four-Tips Optical Fiber Probe in Slurry Bubble Column

    Directory of Open Access Journals (Sweden)

    Yasser Imad Abdulaziz

    2016-02-01

    Full Text Available In wide range of chemical, petrochemical and energy processes, it is not possible to manage without slurry bubble column reactors. In this investigation, time average local gas holdup was recorded for three different height to diameter (H/D ratios 3, 4 and 5 in 18" diameter slurry bubble column. Air-water-glass beads system was used with superficial velocity up to 0.24 m/s. the gas holdup was measured using 4-tips optical fiber probe technique. The results show that the axial gas holdup increases almost linearly with the superficial gas velocity in 0.08 m/s and levels off with a further increase of velocity. A comparison of the present data with those reported for other slurry bubble column having diameters larger than 18" and H/D higher than 5 indicated that there is little effect of diameter on gas holdup. Also, local section-average gas holdups increase with increasing superficial gas velocity, while the effect of solid loading are less significant than that of superficial gas velocity.

  6. Fuzzy control of dissolved oxygen, pH and temperature of bubble column bioreactor for Candida utilis biomass production

    Directory of Open Access Journals (Sweden)

    Hubert Arteaga Miñano

    2012-06-01

    Full Text Available An automatic control system by dissolved oxygen (DO fuzzy logic, pH and temperature in a bubble column bioreactor (BCB for Candida utilis CECT 10704 biomass production was implemented. Their performance was compared with the classical proportional control. A data acquisition card for the control was designed, built and programmed, using the 4.14 Eagle software for the design and the 3.0 Microcode Studio Plus for programming. A program in 6.0 Visual Basic, which linked up with 7.0 MatLab for fuzzy control was developed; using Mandani inference, membership functions of input and output trapezoidal and triangular; 4 rules for the DO, 3 for pH and 3 for temperature, with connector and type and for defuzzifying the centroid method. Evaluation of biomass production was performed by determining dry weight and growth kinetics with the Gompertz model.The fuzzy control performance of DO, pH and temperature showed superiority in proportional control, characterized by a very close control to set point and a low standard deviation. DO Fuzzy control at 6 ppm, pH of 6 and 30°C, allowed to have the greatest dry weight of 7.65±0.02 g/L and the highest maximum growth of 1.51±0.2, the lowest adaptation phase of 0.27±0.01 h and the greatest specific speed of Candida utilis growth rate of 0.7±0.01 h-1.

  7. Performance of a modified multi-stage bubble column reactor for lead(II) and biological oxygen demand removal from wastewater using activated rice husk

    International Nuclear Information System (INIS)

    Sahu, J.N.; Agarwal, S.; Meikap, B.C.; Biswas, M.N.

    2009-01-01

    The excessive release of wastewater into the environment is a major concern worldwide. Adsorption is the one of the most effective technique for treatment of wastewater. In this work activated carbon prepared from rice husk has been used as an adsorbent. In the present investigation a three phase modified multi-stage bubble column reactor (MMBCR) has been designed to remove lead and biochemical oxygen demand (BOD) from wastewater by means of its adsorption onto the surface of activated rice husk. The multi-staging has been achieved by hydrodynamically induced continuous bubble generation, breakup and regeneration. Under optimum conditions, maximum lead and BOD reduction achieved using activated rice husk was 77.15% and 19.05%, respectively. Results showed MMBCR offered appreciated potential benefits for lead removal from wastewater and BOD removal, even this extent of removal is encouraging and the MMBCR can be used a pretreatment unit before subjecting the wastewater to biological treatment

  8. Performance of a modified multi-stage bubble column reactor for lead(II) and biological oxygen demand removal from wastewater using activated rice husk.

    Science.gov (United States)

    Sahu, J N; Agarwal, S; Meikap, B C; Biswas, M N

    2009-01-15

    The excessive release of wastewater into the environment is a major concern worldwide. Adsorption is the one of the most effective technique for treatment of wastewater. In this work activated carbon prepared from rice husk has been used as an adsorbent. In the present investigation a three phase modified multi-stage bubble column reactor (MMBCR) has been designed to remove lead and biochemical oxygen demand (BOD) from wastewater by means of its adsorption onto the surface of activated rice husk. The multi-staging has been achieved by hydrodynamically induced continuous bubble generation, breakup and regeneration. Under optimum conditions, maximum lead and BOD reduction achieved using activated rice husk was 77.15% and 19.05%, respectively. Results showed MMBCR offered appreciated potential benefits for lead removal from wastewater and BOD removal, even this extent of removal is encouraging and the MMBCR can be used a pretreatment unit before subjecting the wastewater to biological treatment.

  9. Effects of alcohols on gas holdup and volumetric liquid-phase mass transfer coefficient in gel-particle-suspended bubble column

    Energy Technology Data Exchange (ETDEWEB)

    Salvacion, J.; Murayama, M.; Otaguchi, K.; Koide, K. [Tokyo Institute of Technology, Tokyo (Japan)

    1995-08-20

    The effects of alcohols, column dimensions, gas velocity, physical properties of liquids, and gel particles on the gas holdup e{sub G} and the volumetric liquid-phase mass transfer coefficient k{sub L}a in a gel-particle-suspended bubble column under liquid-solid batch operation were studied experimentally. It was shown that addition of at alcohols to water generally increases e{sub G}. However, k{sub L}a values in aqueous solutions of alcohols became larger or smaller than those in water, according to the kind and concentration of the alcohol added to water. It was also shown that the presence of suspended gel-particles in the bubble column reduces values of e{sub G} and k{sub L}a. Based on these observations, empirical equations for e{sub G} in the transition regime in an ethanol solution, for e{sub G} in the heterogeneous now regime applicable to various alcohol solutions and for k{sub L}a in both now regimes were proposed. 18 refs., 12 figs., 3 tabs.

  10. Modeling Cryptosporidium spp. Oocyst Inactivation in Bubble-Diffuser Ozone Contactors

    Science.gov (United States)

    1998-07-01

    requirements for Giardia lamblia (G. lamblia) and viruses under the Surface Water Treatment Rule (SWTR). Minimum CT requirements include relatively...parvum and C. muris ) oocysts in ozone bubble-diffuser contactors. The model is calibrated with semi-batch kinetic data, verified with pilot-scale

  11. Chaotic bubbling and nonstagnant foams.

    Science.gov (United States)

    Tufaile, Alberto; Sartorelli, José Carlos; Jeandet, Philippe; Liger-Belair, Gerard

    2007-06-01

    We present an experimental investigation of the agglomeration of bubbles obtained from a nozzle working in different bubbling regimes. This experiment consists of a continuous production of bubbles from a nozzle at the bottom of a liquid column, and these bubbles create a two-dimensional (2D) foam (or a bubble raft) at the top of this column. The bubbles can assemble in various dynamically stable arrangement, forming different kinds of foams in a liquid mixture of water and glycerol, with the effect that the bubble formation regimes influence the foam obtained from this agglomeration of bubbles. The average number of bubbles in the foam is related to the bubble formation frequency and the bubble mean lifetime. The periodic bubbling can generate regular or irregular foam, while a chaotic bubbling only generates irregular foam.

  12. Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column

    Energy Technology Data Exchange (ETDEWEB)

    Hoogeveen, M O [Technische Univ. Delft (Netherlands). Lab. voor Fysische Technologie

    1993-12-01

    In this work the possibility of the use of gamma radiation in investigating bubbles in a large three dimensional gas-fluidised bed was examined. A measuring system was designed based upon the absorption of gamma radiation. As high energy (>100 keV) gamma radiation penetrates deeply into matter, it can be used to scan through a gas-solid fluidised bed. The attenuation of a beam of mono-energetic photons is related to the amount of solid particles in the path of the beam. With the gamma absorption technique two parameters can be determined: The void fraction and the bubble velocity. With one narrow beam of gamma radiation a chordal void fraction can be measured in the homogeneous part of the bed. An optimalisation procedure for the void fraction determination led to the choice of Cs-137 as radiation source. This optimalisation procedure concerned minimizing of the standard deviation in the determined chordal void fraction as a function of the energy of gamma radiation. With two narrow parallel beams placed at a distance of 12 cm above each other a bubble velocity can be obtained. A cross-correlation between the two detector responses gives the time shift between the two responses. The system was designed for velocity measurements in the non-homogeneous part of the column. A simulation of the two beam measurement method for an air fluidized bed, 0.40 m in diameter, of polystyrene particles led to the choice of 100 mCi for the source strength for each of the two Cs-137 sources. For a 100 mCi Cs-137 source a shielding of 8 cm of lead is necessary to comply with safety regulations, concerning the use of radioactive materials. A source holder was designed, containing two encapsulated 100 mCi Cs-137 sources, in accordance with the regulations in the licence of the Delft University of Technology for the use of encapsulated sources. (orig.).

  13. Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column

    International Nuclear Information System (INIS)

    Hoogeveen, M.O.

    1993-12-01

    In this work the possibility of the use of gamma radiation in investigating bubbles in a large three dimensional gas-fluidised bed was examined. A measuring system was designed based upon the absorption of gamma radiation. As high energy (>100 keV) gamma radiation penetrates deeply into matter, it can be used to scan through a gas-solid fluidised bed. The attenuation of a beam of mono-energetic photons is related to the amount of solid particles in the path of the beam. With the gamma absorption technique two parameters can be determined: The void fraction and the bubble velocity. With one narrow beam of gamma radiation a chordal void fraction can be measured in the homogeneous part of the bed. An optimalisation procedure for the void fraction determination led to the choice of Cs-137 as radiation source. This optimalisation procedure concerned minimizing of the standard deviation in the determined chordal void fraction as a function of the energy of gamma radiation. With two narrow parallel beams placed at a distance of 12 cm above each other a bubble velocity can be obtained. A cross-correlation between the two detector responses gives the time shift between the two responses. The system was designed for velocity measurements in the non-homogeneous part of the column. A simulation of the two beam measurement method for an air fluidized bed, 0.40 m in diameter, of polystyrene particles led to the choice of 100 mCi for the source strength for each of the two Cs-137 sources. For a 100 mCi Cs-137 source a shielding of 8 cm of lead is necessary to comply with safety regulations, concerning the use of radioactive materials. A source holder was designed, containing two encapsulated 100 mCi Cs-137 sources, in accordance with the regulations in the licence of the Delft University of Technology for the use of encapsulated sources. (orig.)

  14. Demonstration of two-phase Direct Numerical Simulation (DNS) methods potentiality to give information to averaged models: application to bubbles column

    International Nuclear Information System (INIS)

    Magdeleine, S.

    2009-11-01

    This work is a part of a long term project that aims at using two-phase Direct Numerical Simulation (DNS) in order to give information to averaged models. For now, it is limited to isothermal bubbly flows with no phase change. It could be subdivided in two parts: Firstly, theoretical developments are made in order to build an equivalent of Large Eddy Simulation (LES) for two phase flows called Interfaces and Sub-grid Scales (ISS). After the implementation of the ISS model in our code called Trio U , a set of various cases is used to validate this model. Then, special test are made in order to optimize the model for our particular bubbly flows. Thus we showed the capacity of the ISS model to produce a cheap pertinent solution. Secondly, we use the ISS model to perform simulations of bubbly flows in column. Results of these simulations are averaged to obtain quantities that appear in mass, momentum and interfacial area density balances. Thus, we processed to an a priori test of a complete one dimensional averaged model.We showed that this model predicts well the simplest flows (laminar and monodisperse). Moreover, the hypothesis of one pressure, which is often made in averaged model like CATHARE, NEPTUNE and RELAP5, is satisfied in such flows. At the opposite, without a polydisperse model, the drag is over-predicted and the uncorrelated A i flux needs a closure law. Finally, we showed that in turbulent flows, fluctuations of velocity and pressure in the liquid phase are not represented by the tested averaged model. (author)

  15. Power to Fuels: Dynamic Modeling of a Slurry Bubble Column Reactor in Lab-Scale for Fischer Tropsch Synthesis under Variable Load of Synthesis Gas

    Directory of Open Access Journals (Sweden)

    Siavash Seyednejadian

    2018-03-01

    Full Text Available This research developed a comprehensive computer model for a lab-scale Slurry Bubble Column Reactor (SBCR (0.1 m Dt and 2.5 m height for Fischer–Tropsch (FT synthesis under flexible operation of synthesis gas load flow rates. The variable loads of synthesis gas are set at 3.5, 5, 7.5 m3/h based on laboratory adjustments at three different operating temperatures (483, 493 and 503 K. A set of Partial Differential Equations (PDEs in the form of mass transfer and chemical reaction are successfully coupled to predict the behavior of all the FT components in two phases (gas and liquid over the reactor bed. In the gas phase, a single-bubble-class-diameter (SBCD is adopted and the reduction of superficial gas velocity through the reactor length is incorporated into the model by the overall mass balance. Anderson Schulz Flory distribution is employed for reaction kinetics. The modeling results are in good agreement with experimental data. The results of dynamic modeling show that the steady state condition is attained within 10 min from start-up. Furthermore, they show that step-wise syngas flow rate does not have a detrimental influence on FT product selectivity and the dynamic modeling of the slurry reactor responds quite well to the load change conditions.

  16. A Laboratory Experiment To Measure Henry's Law Constants of Volatile Organic Compounds with a Bubble Column and a Gas Chromatography Flame Ionization Detector (GC-FID)

    Science.gov (United States)

    Lee, Shan-Hu; Mukherjee, Souptik; Brewer, Brittany; Ryan, Raphael; Yu, Huan; Gangoda, Mahinda

    2013-01-01

    An undergraduate laboratory experiment is described to measure Henry's law constants of organic compounds using a bubble column and gas chromatography flame ionization detector (GC-FID). This experiment is designed for upper-division undergraduate laboratory courses and can be implemented in conjunction with physical chemistry, analytical…

  17. Reliable prediction of heat transfer coefficient in three-phase bubble column reactor via adaptive neuro-fuzzy inference system and regularization network

    Science.gov (United States)

    Garmroodi Asil, A.; Nakhaei Pour, A.; Mirzaei, Sh.

    2018-04-01

    In the present article, generalization performances of regularization network (RN) and optimize adaptive neuro-fuzzy inference system (ANFIS) are compared with a conventional software for prediction of heat transfer coefficient (HTC) as a function of superficial gas velocity (5-25 cm/s) and solid fraction (0-40 wt%) at different axial and radial locations. The networks were trained by resorting several sets of experimental data collected from a specific system of air/hydrocarbon liquid phase/silica particle in a slurry bubble column reactor (SBCR). A special convection HTC measurement probe was manufactured and positioned in an axial distance of 40 and 130 cm above the sparger at center and near the wall of SBCR. The simulation results show that both in-house RN and optimized ANFIS due to powerful noise filtering capabilities provide superior performances compared to the conventional software of MATLAB ANFIS and ANN toolbox. For the case of 40 and 130 cm axial distance from center of sparger, at constant superficial gas velocity of 25 cm/s, adding 40 wt% silica particles to liquid phase leads to about 66% and 69% increasing in HTC respectively. The HTC in the column center for all the cases studied are about 9-14% larger than those near the wall region.

  18. Cutting bubbles with a single wire

    NARCIS (Netherlands)

    Baltussen, M.W.; Segers, Q.I.E.; Kuipers, J.A.M.; Deen, N.G.

    2017-01-01

    Many gas-liquid-solid contactors, such as trickle bed and bubble slurry columns, suffer from heat and mass transfer limitations. To overcome these limitations, new micro-structured bubble column reactor is proposed. In this reactor, a catalyst coated wire mesh is introduced in a bubble column to cut

  19. Performance and microbial community composition dynamics of aerobic granular sludge from sequencing batch bubble column reactors operated at 20 degrees C, 30 degrees C, and 35 degrees C.

    Science.gov (United States)

    Ebrahimi, Sirous; Gabus, Sébastien; Rohrbach-Brandt, Emmanuelle; Hosseini, Maryam; Rossi, Pierre; Maillard, Julien; Holliger, Christof

    2010-07-01

    Two bubble column sequencing batch reactors fed with an artificial wastewater were operated at 20 degrees C, 30 degrees C, and 35 degrees C. In a first stage, stable granules were obtained at 20 degrees C, whereas fluffy structures were observed at 30 degrees C. Molecular analysis revealed high abundance of the operational taxonomic unit 208 (OTU 208) affiliating with filamentous bacteria Leptothrix spp. at 30 degrees C, an OTU much less abundant at 20 degrees C. The granular sludge obtained at 20 degrees C was used for the second stage during which one reactor was maintained at 20 degrees C and the second operated at 30 degrees C and 35 degrees C after prior gradual increase of temperature. Aerobic granular sludge with similar physical properties developed in both reactors but it had different nutrient elimination performances and microbial communities. At 20 degrees C, acetate was consumed during anaerobic feeding, and biological phosphorous removal was observed when Rhodocyclaceae-affiliating OTU 214 was present. At 30 degrees C and 35 degrees C, acetate was mainly consumed during aeration and phosphorous removal was insignificant. OTU 214 was almost absent but the Gammaproteobacteria-affiliating OTU 239 was more abundant than at 20 degrees C. Aerobic granular sludge at all temperatures contained abundantly the OTUs 224 and 289 affiliating with Sphingomonadaceae indicating that this bacterial family played an important role in maintaining stable granular structures.

  20. On the interaction of Taylor bubbles rising in two-phase co-current slug flow in vertical columns: turbulent wakes

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, A.M.F.R.; Campos, J.B.L. [Centro de Estudos de Fenomenos de Transporte, Universidade do Porto Rua (Portugal); Coelho Pinheiro, M.N. [Dept. de Engenharia Quimica, Politecnico de Coimbra (Portugal)

    2001-12-01

    An experimental study on the interaction between Taylor bubbles rising through a co-current flowing liquid in a vertical tube with 32 mm of internal diameter is reported. The flow pattern in the bubble's wake was turbulent and the flow regime in the liquid slug was either turbulent or laminar. When the flow regime in the liquid slug is turbulent (i) the minimum distance between bubbles above which there is no interaction is 5D-6D; (ii) the bubble's rising velocity is in excellent agreement with the Nicklin relation; (iii) the experimental values of the bubble length compare well with theoretical predictions (Barnea 1990); (iv) the distance between consecutive bubbles varied from 13D to 16D and is insensitive to the liquid Reynolds number. When the flow regime in the liquid slug is laminar (i) the wake length is about 5D-6D; (ii) the minimum distance between bubbles above which there is no interaction is higher than 25D; (iii) the bubble's rising velocity is significantly smaller than theoretical predictions. These results were explained in the light of the findings of Pinto et al. (1998) on coalescence of two Taylor bubbles rising through a co-current liquid. (orig.)

  1. Gas-liquid reactive crystallization kinetics of 2,4,6-triamino-1,3,5-trinitrobenzene in the semi-batch procedure

    Science.gov (United States)

    Liu, Ruqin; Huang, Ming; Yao, Xiaolu; Chen, Shuang; Wang, Shucun; Suo, Zhirong

    2018-06-01

    2,4,6-Triamino-1,3,5-trinitrobenzene is the attractive insensitive high energetic material used extensively in the military and civil fields. Combined with the double-films theory, the global gas-liquid chemical reaction kinetics of 2,4,6-triamino-1,3,5-trinitrobenzene was developed by means of the infinitesimal material balance calculation. The raw material concentration and reactive temperature effects on the crystallization of 2,4,6-triamino-1,3,5-trinitrobenzene were investigated by the batch experiments. The reactive crystallization kinetics associated ammonia feeding rate of 2,4,6-triamino-1,3,5-trinitrobenzene, including nucleation as well as crystal growth, was systematically investigated in the heterogonous semi-batch procedure. The nucleation and crystal growth kinetic exponents were estimated by the linear least-squares method. The crystallization kinetic results indicated that nucleation rate strongly increased but liner growth rate decreased with the increasing of ammonia feeding rate. In terms of manufacturing coarse 2,4,6-triamino-1,3,5-trinitrobenzene, it was found that a slow ammonia feeding rate and a low raw material concentration were feasible under the present experimental conditions.

  2. Science Bubbles

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Pedersen, David Budtz

    2013-01-01

    Much like the trade and trait sof bubbles in financial markets,similar bubbles appear on the science market. When economic bubbles burst, the drop in prices causes the crash of unsustainable investments leading to an investor confidence crisis possibly followed by a financial panic. But when...... bubbles appear in science, truth and reliability are the first victims. This paper explores how fashions in research funding and research management may turn science into something like a bubble economy....

  3. Bubble point measurement and high pressure distillation column design for the environmentally benign separation of zirconium from hafnium for nuclear power reactor

    International Nuclear Information System (INIS)

    Minh, Le Quang; Kim, Gyeongmin; Lee, Moonyong; Park, Jongki

    2015-01-01

    We examined the feasible separation of ZrCl 4 and HfCl 4 through high pressure distillation as environmentally benign separation for structural material of nuclear power reactor. The bubble point pressures of ZrCl 4 and HfCl 4 mixtures were determined experimentally by using an invariable volume equilibrium cell at high pressure and temperature condition range of 2.3-5..6MPa and 440-490 .deg. C. The experimental bubble point pressure data were correlated with Peng-Robinson equation of state with a good agreement. Based on the vapor-liquid equilibrium properties evaluated from the experimental data, the feasibility of high pressure distillation process for the separation of ZrCl 4 and HfCl 4 was investigated with its main design condition through rigorous simulation using a commercial process simulator, ASPEN Hysys. An enhanced distillation configuration was also proposed to improve energy efficiency in the distillation process. The result showed that a heat-pump assisted distillation with a partial bottom flash could be a promising option for commercial separation of ZrCl 4 and HfCl 4 by taking into account of both energy and environmental advantages

  4. Sticky bubbles

    NARCIS (Netherlands)

    Antoniuk, O.; Bos, van der A.; Driessen, T.W.; Es, van B.; Jeurissen, R.J.M.; Michler, D.; Reinten, H.; Schenker, M.; Snoeijer, J.H.; Srivastava, S.; Toschi, F.; Wijshoff, H.M.A.

    2011-01-01

    We discuss the physical forces that are required to remove an air bubble immersed in a liquid from a corner. This is relevant for inkjet printing technology, as the presence of air bubbles in the channels of a printhead perturbs the jetting of droplets. A simple strategy to remove the bubble is to

  5. Freezing Bubbles

    Science.gov (United States)

    Kingett, Christian; Ahmadi, Farzad; Nath, Saurabh; Boreyko, Jonathan

    2017-11-01

    The two-stage freezing process of a liquid droplet on a substrate is well known; however, how bubbles freeze has not yet been studied. We first deposited bubbles on a silicon substrate that was chilled at temperatures ranging from -10 °C to -40 °C, while the air was at room temperature. We observed that the freeze front moved very slowly up the bubble, and in some cases, even came to a complete halt at a critical height. This slow freezing front propagation can be explained by the low thermal conductivity of the thin soap film, and can be observed more clearly when the bubble size or the surface temperature is increased. This delayed freezing allows the frozen portion of the bubble to cool the air within the bubble while the top part is still liquid, which induces a vapor pressure mismatch that either collapses the top or causes the top to pop. In cases where the freeze front reaches the top of the bubble, a portion of the top may melt and slowly refreeze; this can happen more than just once for a single bubble. We also investigated freezing bubbles inside of a freezer where the air was held at -20 °C. In this case, the bubbles freeze quickly and the ice grows radially from nucleation sites instead of perpendicular to the surface, which provides a clear contrast with the conduction limited room temperature bubbles.

  6. Hydrodynamics in a swarm of rising bubbles

    International Nuclear Information System (INIS)

    Riboux, G.

    2007-04-01

    In many applications, bubbles are used to agitate a liquid in order to enhance mixing and transfer. This work is devoted to the study of the hydrodynamics in a stable bubble column. Experimentally, we have determined the properties of the velocity fluctuations inside and behind a homogeneous swarm of rising bubbles for different bubble sizes and gas volume fractions α: self-similarity in α 0,4 , spectrum in k -3 and integral length scale controlled by buoyancy. Numerically, we have reproduced these properties by means of large-scale simulations, the bubbles being modeled by volume-forces. This confirms that the dynamics is controlled by wake interactions. (author)

  7. Bubble systems

    CERN Document Server

    Avdeev, Alexander A

    2016-01-01

    This monograph presents a systematic analysis of bubble system mathematics, using the mechanics of two-phase systems in non-equilibrium as the scope of analysis. The author introduces the thermodynamic foundations of bubble systems, ranging from the fundamental starting points to current research challenges. This book addresses a range of topics, including description methods of multi-phase systems, boundary and initial conditions as well as coupling requirements at the phase boundary. Moreover, it presents a detailed study of the basic problems of bubble dynamics in a liquid mass: growth (dynamically and thermally controlled), collapse, bubble pulsations, bubble rise and breakup. Special emphasis is placed on bubble dynamics in turbulent flows. The analysis results are used to write integral equations governing the rate of vapor generation (condensation) in non-equilibrium flows, thus creating a basis for solving a number of practical problems. This book is the first to present a comprehensive theory of boil...

  8. Bubbles & Squat

    DEFF Research Database (Denmark)

    Højbjerre Larsen, Signe

    , a new concept called ‘Bubbles & Squat’, where fitness training is combined with Champagne and a live DJ. One of the invitations for this event describes how “we spice up your friday training with live DJ and lots of refreshing bubbles, to make sure that you are ready for the weekend (...).” Before New...

  9. Adhesion of solid particles to gas bubbles. Part 2: Experimental

    NARCIS (Netherlands)

    Omota, Florin; Dimian, Alexandre C.; Bliek, A.

    2006-01-01

    In slurry bubble columns, the adhesion of solid catalyst particles to bubbles may significantly affect the G–L mass transfer and bubble size distribution. This feature may be exploited in design by modifying the hydrophilic or hydrophobic nature of the particles used. Previously we have proposed a

  10. A numerical study of cutting bubbles with a wire mesh

    NARCIS (Netherlands)

    Baltussen, M.W.; Kuipers, J.A.M.; Deen, N.G.

    2017-01-01

    Gas-liquid-solid flows are frequently encountered in chemical, petrochemical and biochemical industries. To overcome the heat and mass transfer limitations in trickle bed reactors and bubble slurry columns, respectively, a micro-structured bubble column (MSBC) can serve as an attractive alternative.

  11. Computational and Experimental Study of Bubble Size in Bubble Columns

    DEFF Research Database (Denmark)

    Hansen, Rolf

    sammenklumpning og opbrydning af bobler, hvorved en Sauter gennemsnitsdiameter (SMD) beregnes i domænet. Boblestørrelsesfordelingen måles i en kvadratisk boblekolonne med ”Interferometric Particle Imaging” (IPI), som er en ikke-indtrængende optisk laserbaseret metode. Boblehastigheden måles samtidig med ”Particle...... Tracking Velocimetry” (PTV). Målingerne udføres for tre superficielle gashastigheder i en plan i midten af boblekolonnen. IPImålingerne viser en SMD på omkring 6.0mm for hele måleområdet, hvilket også er observeret visuelt. Lokale boblestørrelseshistogrammer præsenteres for at få data, der kan sammenlignes...... med beregningerne. Den eksperimentelle SMD synes at være konstant lodret gennem boblekolonnen, men faldende fra midten ind mod væggen horisontalt. Den eksperimentelle SMD synes også at falde med stigende superficiel gashastighed.  En beregningsanalyse af flowmønstret i den kvadratiske boblekolonne er...

  12. Bubbling away

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-10-15

    Bubble chambers may have almost vanished from the front line of physics research, but the vivid memory of their intricate and sometimes beautiful patterns of particle tracks lives on, and has greatly influenced the computer graphics of track reconstruction in today's big experiments. 'Seeing' an interaction makes it more understandable. Bubble chambers, with their big collaborations of physicists from many widely scattered research institutes, started another ball rolling. The groups formed are even now only surpassed in size by the big collaborations working on today's major detectors at colliding beam machines. From 14-16 July, about 130 physicists gathered at CERN to commemorate the 40th anniversary of the invention of the bubble chamber by Donald Glaser. The meeting, organized by Derek C. Colley from Birmingham, gave a comprehensive overview of bubble chamber contributions to physics, their challenging technology, and the usefulness of bubble chamber photographs in education, both for physics and the public at large. After opening remarks by CERN Director Carlo Rubbia, Donald Glaser began with a brief review of the work which led to his invention - there was much more to it than idly watching beer bubbles rise up the wall of the glass - before turning to his present line of research, biophysics, also very visually oriented.

  13. Bubbling away

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Bubble chambers may have almost vanished from the front line of physics research, but the vivid memory of their intricate and sometimes beautiful patterns of particle tracks lives on, and has greatly influenced the computer graphics of track reconstruction in today's big experiments. 'Seeing' an interaction makes it more understandable. Bubble chambers, with their big collaborations of physicists from many widely scattered research institutes, started another ball rolling. The groups formed are even now only surpassed in size by the big collaborations working on today's major detectors at colliding beam machines. From 14-16 July, about 130 physicists gathered at CERN to commemorate the 40th anniversary of the invention of the bubble chamber by Donald Glaser. The meeting, organized by Derek C. Colley from Birmingham, gave a comprehensive overview of bubble chamber contributions to physics, their challenging technology, and the usefulness of bubble chamber photographs in education, both for physics and the public at large. After opening remarks by CERN Director Carlo Rubbia, Donald Glaser began with a brief review of the work which led to his invention - there was much more to it than idly watching beer bubbles rise up the wall of the glass - before turning to his present line of research, biophysics, also very visually oriented

  14. Nuttier bubbles

    International Nuclear Information System (INIS)

    Astefanesei, Dumitru; Mann, Robert B.; Stelea, Cristian

    2006-01-01

    We construct new explicit solutions of general relativity from double analytic continuations of Taub-NUT spacetimes. This generalizes previous studies of 4-dimensional nutty bubbles. One 5-dimensional locally asymptotically AdS solution in particular has a special conformal boundary structure of AdS 3 x S 1 . We compute its boundary stress tensor and relate it to the properties of the dual field theory. Interestingly enough, we also find consistent 6-dimensional bubble solutions that have only one timelike direction. The existence of such spacetimes with non-trivial topology is closely related to the existence of the Taub-NUT(-AdS) solutions with more than one NUT charge. Finally, we begin an investigation of generating new solutions from Taub-NUT spacetimes and nuttier bubbles. Using the so-called Hopf duality, we provide new explicit time-dependent backgrounds in six dimensions

  15. Leverage bubble

    Science.gov (United States)

    Yan, Wanfeng; Woodard, Ryan; Sornette, Didier

    2012-01-01

    Leverage is strongly related to liquidity in a market and lack of liquidity is considered a cause and/or consequence of the recent financial crisis. A repurchase agreement is a financial instrument where a security is sold simultaneously with an agreement to buy it back at a later date. Repurchase agreement (repo) market size is a very important element in calculating the overall leverage in a financial market. Therefore, studying the behavior of repo market size can help to understand a process that can contribute to the birth of a financial crisis. We hypothesize that herding behavior among large investors led to massive over-leveraging through the use of repos, resulting in a bubble (built up over the previous years) and subsequent crash in this market in early 2008. We use the Johansen-Ledoit-Sornette (JLS) model of rational expectation bubbles and behavioral finance to study the dynamics of the repo market that led to the crash. The JLS model qualifies a bubble by the presence of characteristic patterns in the price dynamics, called log-periodic power law (LPPL) behavior. We show that there was significant LPPL behavior in the market before that crash and that the predicted range of times predicted by the model for the end of the bubble is consistent with the observations.

  16. Champagne experiences various rhythmical bubbling regimes in a flute.

    Science.gov (United States)

    Liger-Belair, Gérard; Tufaile, Alberto; Jeandet, Philippe; Sartorelli, José-Carlos

    2006-09-20

    Bubble trains are seen rising gracefully from a few points on the glass wall (called nucleation sites) whenever champagne is poured into a glass. As time passes during the gas-discharging process, the careful observation of some given bubble columns reveals that the interbubble distance may change suddenly, thus revealing different rhythmical bubbling regimes. Here, it is reported that the transitions between the different bubbling regimes of some nucleation sites during gas discharging is a process which may be ruled by a strong interaction between tiny gas pockets trapped inside the nucleation site and/or also by an interaction between the tiny bubbles just blown from the nucleation site.

  17. Bubble bath soap poisoning

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002762.htm Bubble bath soap poisoning To use the sharing features on this page, please enable JavaScript. Bubble bath soap poisoning occurs when someone swallows bubble bath soap. ...

  18. Rational equity bubbles

    OpenAIRE

    Zhou, Ge

    2012-01-01

    This paper discusses the existence of a bubble in the pricing of an asset that pays positive dividends. I show that rational bubbles can exist in a growing economy. The existence of bubbles depends on the relative magnitudes of risk aversion to consumption and to wealth. Furthermore, I examine how an exogenous shock in technology might trigger bubbles.

  19. Fama on Bubbles

    DEFF Research Database (Denmark)

    Engsted, Tom

    2016-01-01

    While Eugene Fama has repeatedly expressed his discontent with the notion of an “irrational bubble,” he has never publicly expressed his opinion on “rational bubbles.” On empirical grounds Fama rejects bubbles by referring to the lack of reliable evidence that price declines are predictable....... However, this argument cannot be used to rule out rational bubbles because such bubbles do not necessarily imply return predictability, and return predictability of the kind documented by Fama does not rule out rational bubbles. On data samples that include the 1990s, there is evidence of an explosive...... component in stock market valuation ratios, consistent with a rational bubble....

  20. Anti-Bubbles

    Science.gov (United States)

    Tufaile, Alberto; Sartorelli, José Carlos

    2003-08-01

    An anti-bubble is a striking kind of bubble in liquid that seemingly does not comply the buoyancy, and after few minutes it disappears suddenly inside the liquid. Different from a simple air bubble that rises directly to the liquid surface, an anti-bubble wanders around in the fluid due to its slightly lesser density than the surrounding liquid. In spite of this odd behavior, an anti-bubble can be understood as the opposite of a conventional soap bubble in air, which is a shell of liquid surrounding air, and an anti-bubble is a shell of air surrounding a drop of the liquid inside the liquid. Two-phase flow has been a subject of interest due to its relevance to process equipment for contacting gases and liquids applied in industry. A chain of bubbles rising in a liquid formed from a nozzle is a two-phase flow, and there are certain conditions in which spherical air shells, called anti-bubbles, are produced. The purpose of this work is mainly to note the existence of anti-bubbling regime as a sequel of a bubbling system. We initially have presented the experimental apparatus. After this we have described the evolution of the bubbling regimes, and emulated the effect of bubbling coalescence with simple maps. Then is shown the inverted dripping as a consequence of the bubble coalescence, and finally the conditions for anti-bubble formation.

  1. Development of the bubble rise model in RELAP-UK

    International Nuclear Information System (INIS)

    Holmes, J.A.

    1977-11-01

    Several improvements have been made to the 'bubble rise calculation' in the code RELAP-UK, which models the separation of the steam and water phases within specified volumes of the coolant circuit. The bubble rise velocity and the bubble density gradient parameter are no longer necessarily user-defined constants, as the code can calculate their values at each time step according to the local fluid conditions. In particular, the calculation of the bubble rise velocity is consistent with the RELAP-UK drift flux correlation. It is now possible to represent a vertical column by a stack of vertically-adjacent bubble-rise volumes. Any mixture level existing within the column can freely pass between the volumes in the stack. The facilities are demonstrated in this paper by a simple computational example. (author)

  2. Fluid dynamics of bubbly flows

    International Nuclear Information System (INIS)

    Ziegenhein, Thomas

    2016-01-01

    Bubbly flows can be found in many applications in chemical, biological and power engineering. Reliable simulation tools of such flows that allow the design of new processes and optimization of existing one are therefore highly desirable. CFD-simulations applying the multi-fluid approach are very promising to provide such a design tool for complete facilities. In the multi-fluid approach, however, closure models have to be formulated to model the interaction between the continuous and dispersed phase. Due to the complex nature of bubbly flows, different phenomena have to be taken into account and for every phenomenon different closure models exist. Therefore, reliable predictions of unknown bubbly flows are not yet possible with the multi-fluid approach. A strategy to overcome this problem is to define a baseline model in which the closure models including the model constants are fixed so that the limitations of the modeling can be evaluated by validating it on different experiments. Afterwards, the shortcomings are identified so that the baseline model can be stepwise improved without losing the validity for the already validated cases. This development of a baseline model is done in the present work by validating the baseline model developed at the Helmholtz-Zentrum Dresden-Rossendorf mainly basing on experimental data for bubbly pipe flows to bubble columns, bubble plumes and air-lift reactors that are relevant in chemical and biological engineering applications. In the present work, a large variety of such setups is used for validation. The buoyancy driven bubbly flows showed thereby a transient behavior on the scale of the facility. Since such large scales are characterized by the geometry of the facility, turbulence models cannot describe them. Therefore, the transient simulation of bubbly flows with two equation models based on the unsteady Reynolds-averaged Navier-Stokes equations is investigated. In combination with the before mentioned baseline model these

  3. Fluid dynamics of bubbly flows

    Energy Technology Data Exchange (ETDEWEB)

    Ziegenhein, Thomas

    2016-07-08

    Bubbly flows can be found in many applications in chemical, biological and power engineering. Reliable simulation tools of such flows that allow the design of new processes and optimization of existing one are therefore highly desirable. CFD-simulations applying the multi-fluid approach are very promising to provide such a design tool for complete facilities. In the multi-fluid approach, however, closure models have to be formulated to model the interaction between the continuous and dispersed phase. Due to the complex nature of bubbly flows, different phenomena have to be taken into account and for every phenomenon different closure models exist. Therefore, reliable predictions of unknown bubbly flows are not yet possible with the multi-fluid approach. A strategy to overcome this problem is to define a baseline model in which the closure models including the model constants are fixed so that the limitations of the modeling can be evaluated by validating it on different experiments. Afterwards, the shortcomings are identified so that the baseline model can be stepwise improved without losing the validity for the already validated cases. This development of a baseline model is done in the present work by validating the baseline model developed at the Helmholtz-Zentrum Dresden-Rossendorf mainly basing on experimental data for bubbly pipe flows to bubble columns, bubble plumes and air-lift reactors that are relevant in chemical and biological engineering applications. In the present work, a large variety of such setups is used for validation. The buoyancy driven bubbly flows showed thereby a transient behavior on the scale of the facility. Since such large scales are characterized by the geometry of the facility, turbulence models cannot describe them. Therefore, the transient simulation of bubbly flows with two equation models based on the unsteady Reynolds-averaged Navier-Stokes equations is investigated. In combination with the before mentioned baseline model these

  4. Bubble feature extracting based on image processing of coal flotation froth

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F.; Wang, Y.; Lu, M.; Liu, W. [China University of Mining and Technology, Beijing (China). Dept of Chemical Engineering and Environment

    2001-11-01

    Using image processing the contrast ratio between the bubble on the surface of flotation froth and the image background was enhanced, and the edges of bubble were extracted. Thus a model about the relation between the statistic feature of the bubbles in the image and the cleaned coal can be established. It is feasible to extract the bubble by processing the froth image of coal flotation on the basis of analysing the shape of the bubble. By means of processing the 51 group images sampled from laboratory column, it is thought that the use of the histogram equalization of image gradation and the medium filtering can obviously improve the dynamic contrast range and the brightness of bubbles. Finally, the method of threshold value cut and the bubble edge detecting for extracting the bubble were also discussed to describe the bubble feature, such as size and shape, in the froth image and to distinguish the froth image of coal flotation. 6 refs., 3 figs.

  5. Gas Bubble Dynamics under Mechanical Vibrations

    Science.gov (United States)

    Mohagheghian, Shahrouz; Elbing, Brian

    2017-11-01

    The scientific community has a limited understanding of the bubble dynamics under mechanical oscillations due to over simplification of Navier-Stockes equation by neglecting the shear stress tensor and not accounting for body forces when calculating the acoustic radiation force. The current work experimental investigates bubble dynamics under mechanical vibration and resulting acoustic field by measuring the bubble size and velocity using high-speed imaging. The experimental setup consists of a custom-designed shaker table, cast acrylic bubble column, compressed air injection manifold and an optical imaging system. The mechanical vibrations resulted in accelerations between 0.25 to 10 times gravitational acceleration corresponding to frequency and amplitude range of 8 - 22Hz and 1 - 10mm respectively. Throughout testing the void fraction was limited to <5%. The bubble size is larger than resonance size and smaller than acoustic wavelength. The amplitude of acoustic pressure wave was estimated using the definition of Bjerknes force in combination with Rayleigh-Plesset equation. Physical behavior of the system was capture and classified. Bubble size, velocity as well as size and spatial distribution will be presented.

  6. Fama on bubbles

    DEFF Research Database (Denmark)

    Engsted, Tom

    Eugene Fama has repeatedly expressed his discontent with the notion of an irrational bubble. However, he has never publicly expressed his opinion on rational bubbles. This is peculiar since such bubbles build naturally from the rational efficient markets paradigm that Fama strongly adheres to...

  7. Particle-bubble aggregate stability on static bubble generated by single nozzle on flotation process

    Science.gov (United States)

    Warjito, Harinaldi, Setyantono, Manus; Siregar, Sahala D.

    2016-06-01

    There are three sub-processes on flotation. These processes are intervening liquid film into critical thickness, rupture of liquid film forming three phase contact line, and expansion three phase contact line forming aggregate stability. Aggregate stability factor contribute to determine flotation efficiency. Aggregate stability has some important factors such as reagent and particle geometry. This research focussed on to understand effect of particle geometry to aggregate stability. Experimental setup consists of 9 x 9 x26 cm flotation column made of glass, bubble generator, particle feeding system, and high speed video camera. Bubble generator made from single nozzle with 0.3 mm diameter attached to programmable syringe pump. Particle feeding system made of pipette. Particle used in this research is taken from open pit Grasberg in Timika, Papua. Particle has sub-angular geometry and its size varies from 38 to 300 µm. Bubble-particle interaction are recorded using high speed video camera. Recordings from high speed video camera analyzed using image processing software. Experiment result shows that aggregate particle-bubble and induction time depends on particle size. Small particle (38-106 µm) has long induction time and able to rupture liquid film and also forming three phase contact line. Big particle (150-300 µm) has short induction time, so it unable to attach with bubble easily. This phenomenon is caused by apparent gravity work on particle-bubble interaction. Apparent gravity worked during particle sliding on bubble surface experience increase and reached its maximum magnitude at bubble equator. After particle passed bubble equator, apparent gravity force experience decrease. In conclusion particle size from 38-300 µm can form stable aggregate if particle attached with bubble in certain condition.

  8. Effect study of multi-bubbles on stress distribution of fuel particle

    International Nuclear Information System (INIS)

    Zhao Yi; Wang Xiaomin; Long Chongsheng

    2015-01-01

    The finite element model was proposed to simulate the process of the UO_2 dispersion fuel particle sustaining the internal pressure of multi-bubbles, and the stress distribution of fuel particle with intra-bubbles was calculated. The results show that when the bubbles line equidistantly along x axis, the max normal stress along y axis increases with the number of bubbles, meanwhile, the increment of the normal stress gradually decreases. There is a limit that the effect of bubble's number imposes on the max normal stress in the fuel particle. When multi-column of bubbles exist, the max normal stress along x axis in the fuel particle increases, and the max normal stress along y axis decreases with the increase of the number of bubble column. The stress concentration in the fuel particle decreases with the spacing radius ratio increasing. (authors)

  9. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  10. Bubble coalescence in a Newtonian fluid

    Science.gov (United States)

    Garg, Vishrut; Basaran, Osman

    2017-11-01

    Bubble coalescence plays a central role in the hydrodynamics of gas-liquid systems such as bubble column reactors, spargers, and foams. Two bubbles approaching each other at velocity V coalesce when the thin film between them ruptures, which is often the rate-limiting step. Experimental studies of this system are difficult, and recent works provide conflicting results on the effect of V on coalescence times. We simulate the head-on approach of two bubbles of equal radii R in an incompressible Newtonian fluid (density ρ, viscosity μ, and surface tension σ) by solving numerically the free boundary problem comprised of the Navier Stokes and continuity equations. Simulations are made challenging by the existence of highly disparate lengthscales, i.e. film thickness and drop radii, which are resolved by using the method of elliptic mesh generation. For a given liquid, the bubbles are shown to coalesce for all velocities below a critical value. The effects of Ohnesorge number Oh = μ /√{ ρσR } on coalescence time and critical velocity are also investigated.

  11. Sonoluminescence and bubble fusion

    OpenAIRE

    Arakeri, Vijay H

    2003-01-01

    Sonoluminescence (SL), the phenomenon of light emission from nonlinear motion of a gas bubble, involves an extreme degree of energy focusing. The conditions within the bubble during the last stages of the nearly catastrophic implosion are thought to parallel the efforts aimed at developing inertial confinement fusion. A limited review on the topic of SL and its possible connection to bubble nuclear fusion is presented here. The emphasis is on looking for a link between the various forms o...

  12. Dynamic Bubble Surface Tension Measurements in Northwest Atlantic Seawater

    Science.gov (United States)

    Kieber, D. J.; Long, M. S.; Keene, W. C.; Kinsey, J. D.; Frossard, A. A.; Beaupre, S. R.; Duplessis, P.; Maben, J. R.; Lu, X.; Chang, R.; Zhu, Y.; Bisgrove, J.

    2017-12-01

    Numerous reports suggest that most organic matter (OM) associated with newly formed primary marine aerosol (PMA) originates from the sea-surface microlayer. However, surface-active OM rapidly adsorbs onto bubble surfaces in the water column and is ejected into the atmosphere when bubbles burst at the air-water interface. Here we present dynamic surface tension measurements of bubbles produced in near surface seawater from biologically productive and oligotrophic sites and in deep seawater collected from 2500 m in the northwest Atlantic. In all cases, the surface tension of bubble surfaces decreased within seconds after the bubbles were exposed to seawater. These observations demonstrate that bubble surfaces are rapidly saturated by surfactant material scavenged from seawater. Spatial and diel variability in bubble surface evolution indicate corresponding variability in surfactant concentrations and/or composition. Our results reveal that surface-active OM is found throughout the water column, and that at least some surfactants are not of recent biological origin. Our results also support the hypothesis that the surface microlayer is a minor to negligible source of OM associated with freshly produced PMA.

  13. Prospects for bubble fusion

    Energy Technology Data Exchange (ETDEWEB)

    Nigmatulin, R.I. [Tyumen Institute of Mechanics of Multiphase Systems (TIMMS), Marx (Russian Federation); Lahey, R.T. Jr. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1995-09-01

    In this paper a new method for the realization of fusion energy is presented. This method is based on the superhigh compression of a gas bubble (deuterium or deuterium/thritium) in heavy water or another liquid. The superhigh compression of a gas bubble in a liquid is achieved through forced non-linear, non-periodic resonance oscillations using moderate amplitudes of forcing pressure. The key feature of this new method is a coordination of the forced liquid pressure change with the change of bubble volume. The corresponding regime of the bubble oscillation has been called {open_quotes}basketball dribbling (BD) regime{close_quotes}. The analytical solution describing this process for spherically symmetric bubble oscillations, neglecting dissipation and compressibility of the liquid, has been obtained. This solution shown no limitation on the supercompression of the bubble and the corresponding maximum temperature. The various dissipation mechanisms, including viscous, conductive and radiation heat losses have been considered. It is shown that in spite of these losses it is possible to achieve very high gas bubble temperatures. This because the time duration of the gas bubble supercompression becomes very short when increasing the intensity of compression, thus limiting the energy losses. Significantly, the calculated maximum gas temperatures have shown that nuclear fusion may be possible. First estimations of the affect of liquid compressibility have been made to determine possible limitations on gas bubble compression. The next step will be to investigate the role of interfacial instability and breaking down of the bubble, shock wave phenomena around and in the bubble and mutual diffusion of the gas and the liquid.

  14. Calibration of an accountability tank by bubbling pressure method: correction factors to be taken into account

    International Nuclear Information System (INIS)

    Cauchetier, Ph.

    1993-01-01

    To obtain the needed precision in the calibration of an accountability tank by bubbling pressure method, it requires to use very slow bubbling. The measured data (mass and pressure) must be transformed into physical sizes of the vessel (height and cubic capacity). All corrections to take in account (buoyancy, calibration curve of the sensor, density of the liquid, weight of the gas column, bubbling overpressure, temperature...) are reviewed and valuated. We give the used equations. (author). 3 figs., 1 tab., 2 refs

  15. Soap Bubbles and Crystals

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 6. Soap Bubbles and Crystals. Jean E Taylor. General Article Volume 11 Issue 6 June 2006 pp 26-30. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/011/06/0026-0030. Keywords. Soap bubble ...

  16. Turbulence, bubbles and drops

    NARCIS (Netherlands)

    van der Veen, Roeland

    2016-01-01

    In this thesis, several questions related to drop impact and Taylor-Couette turbulence are answered. The deformation of a drop just before impact can cause a bubble to be entrapped. For many applications, such as inkjet printing, it is crucial to control the size of this entrapped bubble. To study

  17. Single bubble sonoluminescence

    NARCIS (Netherlands)

    Brenner, Michael P.; Hilgenfeldt, Sascha; Lohse, Detlef

    2002-01-01

    Single-bubble sonoluminescence occurs when an acoustically trapped and periodically driven gas bubble collapses so strongly that the energy focusing at collapse leads to light emission. Detailed experiments have demonstrated the unique properties of this system: the spectrum of the emitted light

  18. Flow visualization using bubbles

    International Nuclear Information System (INIS)

    Henry, J.P.

    1974-01-01

    Soap bubbles were used for visualizing flows. The tests effected allowed some characteristics of flows around models in blow tunnels to be precised at mean velocities V 0 5 . The velocity of a bubble is measured by chronophotography, the bulk envelope of the trajectories is also registered [fr

  19. HCDA bubble experiment, (2)

    International Nuclear Information System (INIS)

    Sakata, Kaoru; Mashiko, Hiroyuki; Oka, Yoshiaki; An, Shigehiro; Isozaki, Tadashi.

    1981-06-01

    An experiment simulating the behavior of the very large steam bubbles generated at the time of an accident of core collapse was carried out with a warm water tank, and the applicability of the theory of very small bubble disappearance known at present was examined. The bubbles generated in HCDA (hypothetical core disruptive accident) are expected to be very large, containing sodium, fuel, FP gas and so on, and play important role in the mechanism of emitting radioactive substances in the safety analysis of LMFBRs. In this experiment, the degree of subcool of the warm water pool, the initial radii of steam bubbles and the blowoff pressure of steam were taken as the parameters. The radius of the steam bubbles generated in the experiment was about 6.5 cm, and the state of disappearance was different above and below the degree of unsaturation of 10 deg C. Comparing the disappearance curve obtained by the experiment with the theory of disappearance of small bubbles, the experimental values were between inertia-controlled disappearance and heat transfer-controlled disappearance, and this result was able to be explained generally with the model taking the pressure change within steam bubbles into account. The rise of bubbles was also observed. (Kako, I.)

  20. Bubbles in graphene

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Power, Stephen; Lin, Jun

    2015-01-01

    Strain-induced deformations in graphene are predicted to give rise to large pseudomagnetic fields. We examine theoretically the case of gas-inflated bubbles to determine whether signatures of such fields are present in the local density of states. Sharp-edged bubbles are found to induce Friedel...

  1. Evaporation, Boiling and Bubbles

    Science.gov (United States)

    Goodwin, Alan

    2012-01-01

    Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

  2. Dynamic simulation of dispersed gas-liquid two-phase flow using a discrete bubble model.

    NARCIS (Netherlands)

    Delnoij, E.; Lammers, F.A.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1997-01-01

    In this paper a detailed hydrodynamic model for gas-liquid two-phase flow will be presented. The model is based on a mixed Eulerian-Lagrangian approach and describes the time-dependent two-dimensional motion of small, spherical gas bubbles in a bubble column operating in the homogeneous regime. The

  3. Interfacial Bubble Deformations

    Science.gov (United States)

    Seymour, Brian; Shabane, Parvis; Cypull, Olivia; Cheng, Shengfeng; Feitosa, Klebert

    Soap bubbles floating at an air-water experience deformations as a result of surface tension and hydrostatic forces. In this experiment, we investigate the nature of such deformations by taking cross-sectional images of bubbles of different volumes. The results show that as their volume increases, bubbles transition from spherical to hemispherical shape. The deformation of the interface also changes with bubble volume with the capillary rise converging to the capillary length as volume increases. The profile of the top and bottom of the bubble and the capillary rise are completely determined by the volume and pressure differences. James Madison University Department of Physics and Astronomy, 4VA Consortium, Research Corporation for Advancement of Science.

  4. EXPERIMENTAL BUBBLE FORMATION IN A LARGE SCALE SYSTEM FOR NEWTONIAN AND NONNEWTONIAN FLUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R; Michael Restivo, M

    2008-06-26

    The complexities of bubble formation in liquids increase as the system size increases, and a photographic study is presented here to provide some insight into the dynamics of bubble formation for large systems. Air was injected at the bottom of a 28 feet tall by 30 inch diameter column. Different fluids were subjected to different air flow rates at different fluid depths. The fluids were water and non-Newtonian, Bingham plastic fluids, which have yield stresses requiring an applied force to initiate movement, or shearing, of the fluid. Tests showed that bubble formation was significantly different in the two types of fluids. In water, a field of bubbles was formed, which consisted of numerous, distributed, 1/4 to 3/8 inch diameter bubbles. In the Bingham fluid, large bubbles of 6 to 12 inches in diameter were formed, which depended on the air flow rate. This paper provides comprehensive photographic results related to bubble formation in these fluids.

  5. Theory calculation of combination of 'embryo' bubble growing-up visible bubble in bubble chamber

    International Nuclear Information System (INIS)

    Ye Zipiao; Sheng Xiangdong; Dai Changjiang

    2004-01-01

    By aid of island combination theory of 'embryo' bubble, it is resolved well the question which 'embryo' bubble grows up a visible bubble in the bubble chamber. Through theory calculation it is shown that radius of the big' embryo' bubble combinated not only relates with work matter such as surface tension coefficient, saturation vapour pressure and boiling point of liquid, but also does absorbing quantity of heat and the numbers of 'embryo' bubbles combination. It is explained reasonably that the radius of bubbles in bubble chamber is different for the same energies of neutrons and proton. The track of neutron in bubble chamber is long and thin, and the track of proton in bubble chamber is wide and short. It is also explained reasonably that the bubble radius of the incident particles with more charges which there are the same energies will be wider than that of the incident particles with less charges in the track. (author)

  6. Bubbles and breaking waves

    Science.gov (United States)

    Thorpe, S. A.

    1980-01-01

    The physical processes which control the transfer of gases between the atmosphere and oceans or lakes are poorly understood. Clouds of micro-bubbles have been detected below the surface of Loch Ness when the wind is strong enough to cause the waves to break. The rate of transfer of gas into solution from these bubbles is estimated to be significant if repeated on a global scale. We present here further evidence that the bubbles are caused by breaking waves, and discuss the relationship between the mean frequency of wave breaking at a fixed point and the average distance between breaking waves, as might be estimated from an aerial photograph.

  7. Rotating bubble membrane radiator

    Science.gov (United States)

    Webb, Brent J.; Coomes, Edmund P.

    1988-12-06

    A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating bubble membrane radiator, where it is sprayed into the interior of the bubble. Liquid impacting upon the interior surface of the bubble is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.

  8. Bubble Collision in Curved Spacetime

    International Nuclear Information System (INIS)

    Hwang, Dong-il; Lee, Bum-Hoon; Lee, Wonwoo; Yeom, Dong-han

    2014-01-01

    We study vacuum bubble collisions in curved spacetime, in which vacuum bubbles were nucleated in the initial metastable vacuum state by quantum tunneling. The bubbles materialize randomly at different times and then start to grow. It is known that the percolation by true vacuum bubbles is not possible due to the exponential expansion of the space among the bubbles. In this paper, we consider two bubbles of the same size with a preferred axis and assume that two bubbles form very near each other to collide. The two bubbles have the same field value. When the bubbles collide, the collided region oscillates back-and-forth and then the collided region eventually decays and disappears. We discuss radiation and gravitational wave resulting from the collision of two bubbles

  9. Chemistry in Soap Bubbles.

    Science.gov (United States)

    Lee, Albert W. M.; Wong, A.; Lee, H. W.; Lee, H. Y.; Zhou, Ning-Huai

    2002-01-01

    Describes a laboratory experiment in which common chemical gases are trapped inside soap bubbles. Examines the physical and chemical properties of the gases such as relative density and combustion. (Author/MM)

  10. Nucleation in bubble chambers

    International Nuclear Information System (INIS)

    Harigel, G.G.

    1988-01-01

    Various sources and mechanisms for bubble formation in superheated liquids are discussed. Bubble chambers can be filled with a great variety of liquids, such as e.g. the cryogenic liquids hydrogen, deuterium, neon, neon/hydrogen mixtures, argon, nitrogen, argon/nitrogen mixtures, or the warm liquids propane and various Freon like Freon-13B1. The superheated state is normally achieved by a rapid movement of an expansion piston or membrane, but can also be produced by standing ultrasonic waves, shock waves, or putting liquids under tension. Bubble formation can be initiated by ionizing particles, by intense (laser) light, or on rough surfaces. The creation of embryonic bubbles is not completely understood, but the macroscopic growth and condensation can be calculated, allowing to estimate the dynamic heat load [fr

  11. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  12. CS EMISSION NEAR MIR-BUBBLES

    International Nuclear Information System (INIS)

    Watson, C.; Devine, Kathryn; Quintanar, N.; Candelaria, T.

    2016-01-01

    We survey 44 young stellar objects located near the edges of mid-IR-identified bubbles in CS (1–0) using the Green Bank Telescope. We detect emission in 18 sources, indicating young protostars that are good candidates for being triggered by the expansion of the bubble. We calculate CS column densities and abundances. Three sources show evidence of infall through non-Gaussian line-shapes. Two of these sources are associated with dark clouds and are promising candidates for further exploration of potential triggered star formation. We obtained on-the-fly maps in CS (1–0) of three sources, showing evidence of significant interactions between the sources and the surrounding environment

  13. CS EMISSION NEAR MIR-BUBBLES

    Energy Technology Data Exchange (ETDEWEB)

    Watson, C. [Manchester University, Department of Physics, 604 E. College Ave., North Manchester, IN 46962 (United States); Devine, Kathryn [College of Idaho, Department of Physics, 2112 Cleveland Blvd, Caldwell, ID 83605 (United States); Quintanar, N. [Texas A and M University, Department of Nuclear Engineering, 401 Joe Routt Blvd, College Station, TX 77843 (United States); Candelaria, T., E-mail: cwatson@manchester.edu, E-mail: KDevine@collegeofidaho.edu, E-mail: nrquintanar@tamu.edu, E-mail: tcandela@nmt.edu [New Mexico Institute of Mining and Technology, Department of Physics, 801 Leroy Place, Socorro, NM 87801 (United States)

    2016-02-10

    We survey 44 young stellar objects located near the edges of mid-IR-identified bubbles in CS (1–0) using the Green Bank Telescope. We detect emission in 18 sources, indicating young protostars that are good candidates for being triggered by the expansion of the bubble. We calculate CS column densities and abundances. Three sources show evidence of infall through non-Gaussian line-shapes. Two of these sources are associated with dark clouds and are promising candidates for further exploration of potential triggered star formation. We obtained on-the-fly maps in CS (1–0) of three sources, showing evidence of significant interactions between the sources and the surrounding environment.

  14. Magnetic-bubble devices

    International Nuclear Information System (INIS)

    Fairholme, R.J.

    1978-01-01

    Magnetic bubbles were first described only ten years ago when research workers were discussing orthoferrites containing μm diameter bubbles. However, problems of material fabrication limit crystals to a few mm across which severely curtailed device development. Since then materials have changed and rare-earth-iron garnet films can be grown up 3 inches in diameter with bubble diameters down to sizes below 1 μm. The first commercial products have device capacities in the range 64 000 to 100 000 bits with bubble diameters between 4 and 6 μm. Chip capacities of 1 Mbit are presently under development in the laboratory, as are new techniques to use submicrometre bubbles. The operation and fabrication of a bubble device is described using the serial loop devices currently being manufactured at Plessey as models. Chip organization is one important variable which directly affects the access time. A range of access times and capacities is available which offers a wide range of market opportunities, ranging from consumer products to fixed head disc replacements. some of the application areas are described. (author)

  15. Bubble transport in bifurcations

    Science.gov (United States)

    Bull, Joseph; Qamar, Adnan

    2017-11-01

    Motivated by a developmental gas embolotherapy technique for cancer treatment, we examine the transport of bubbles entrained in liquid. In gas embolotherapy, infarction of tumors is induced by selectively formed vascular gas bubbles that originate from acoustic vaporization of vascular droplets. In the case of non-functionalized droplets with the objective of vessel occlusion, the bubbles are transported by flow through vessel bifurcations, where they may split prior to eventually reach vessels small enough that they become lodged. This splitting behavior affects the distribution of bubbles and the efficacy of flow occlusion and the treatment. In these studies, we investigated bubble transport in bifurcations using computational and theoretical modeling. The model reproduces the variety of experimentally observed splitting behaviors. Splitting homogeneity and maximum shear stress along the vessel walls is predicted over a variety of physical parameters. Maximum shear stresses were found to decrease with increasing Reynolds number. The initial bubble length was found to affect the splitting behavior in the presence of gravitational asymmetry. This work was supported by NIH Grant R01EB006476.

  16. Studies on modelling of bubble driven flows in chemical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Grevskott, Sverre

    1997-12-31

    Multiphase reactors are widely used in the process industry, especially in the petrochemical industry. They very often are characterized by very good thermal control and high heat transfer coefficients against heating and cooling surfaces. This thesis first reviews recent advances in bubble column modelling, focusing on the fundamental flow equations, drag forces, transversal forces and added mass forces. The mathematical equations for the bubble column reactor are developed, using an Eulerian description for the continuous and dispersed phase in tensor notation. Conservation equations for mass, momentum, energy and chemical species are given, and the k-{epsilon} and Rice-Geary models for turbulence are described. The different algebraic solvers used in the model are described, as are relaxation procedures. Simulation results are presented and compared with experimental values. Attention is focused on the modelling of void fractions and gas velocities in the column. The energy conservation equation has been included in the bubble column model in order to model temperature distributions in a heated reactor. The conservation equation of chemical species has been included to simulate absorption of CO{sub 2}. Simulated axial and radial mass fraction profiles for CO{sub 2} in the gas phase are compared with measured values. Simulations of the dynamic behaviour of the column are also presented. 189 refs., 124 figs., 1 tab.

  17. Mechanistic model for dispersion coefficients in bubble column

    CSIR Research Space (South Africa)

    Skosana, PJ

    2015-05-01

    Full Text Available predicts axial and radial dispersion coefficients that are of the same order of magnitude as the reported data. Whereas the model is based on a description of the underlying physical phenomena, its validity and extrapolation is expected to be more reliable...

  18. Radiotracer study in a bubble column reactor (visbreaker)

    International Nuclear Information System (INIS)

    Pant, H.J.; Sharma, V.K.; Gursharan Singh; Rohit Kulkarni; Pandit, A.B.; Kumar, M.M.; Berne, Ph.

    2004-01-01

    Radiotracer technique was used to measure residence time distribution (RTD) of fuel oil in a pilot-plant visbreaker with an objective to investigate hydrodynamic behaviour at different operating conditions. Bromine-82 as dibromobiphenyle was used as a tracer to measure RTD of the fuel oil. Mean residence times were determined from the measured RTD data. Tanks-in-series with backmixing model was used to simulate the measured RTD data. The results of simulation indicated that the visbreaker did not behave as a plug flow reactor as desired for visbreaking process. The presence of internals i.e. baffles inside the visbreaker decreases the mean residence time and backmixing. Thus, the designed internals have shown promising effect in terms of reduced backmixing in the visbreaker. (author)

  19. Experimental Analysis of a Bubble Wake Influenced by a Vortex Street

    Directory of Open Access Journals (Sweden)

    Sophie Rüttinger

    2018-01-01

    Full Text Available Bubble column reactors are ubiquitous in engineering processes. They are used in waste water treatment, as well as in the chemical, pharmaceutical, biological and food industry. Mass transfer and mixing, as well as biochemical or chemical reactions in such reactors are determined by the hydrodynamics of the bubbly flow. The hydrodynamics of bubbly flows is dominated by bubble wake interactions. Despite the fact that bubble wakes have been investigated intensively in the past, there is still a lack of knowledge about how mass transfer from bubbles is influenced by bubble wake interactions in detail. The scientific scope of this work is to answer the question how bubble wakes are influenced by external flow structures like a vortex street behind a cylinder. For this purpose, the flow field in the vicinity of a single bubble is investigated systematically with high spatial and temporal resolution. High-speed Particle Image Velocimetry (PIV measurements are conducted monitoring the flow structure in the equatorial plane of the single bubble. It is shown that the root mean square (RMS velocity profiles downstream the bubble are influenced significantly by the interaction of vortices. In the presence of a vortex street, the deceleration of the fluid behind the bubble is compensated earlier than in the absence of a vortex street. This happens due to momentum transfer by cross-mixing. Both effects indicate that the interaction of vortices enhances the cross-mixing close to the bubble. Time series of instantaneous velocity fields show the formation of an inner shear layer and coupled vortices. In conclusion, this study shows in detail how the bubble wake is influenced by a vortex street and gives deep insights into possible effects on mixing and mass transfer in bubbly flows.

  20. Colliding with a crunching bubble

    Energy Technology Data Exchange (ETDEWEB)

    Freivogel, Ben; Freivogel, Ben; Horowitz, Gary T.; Shenker, Stephen

    2007-03-26

    In the context of eternal inflation we discuss the fate of Lambda = 0 bubbles when they collide with Lambda< 0 crunching bubbles. When the Lambda = 0 bubble is supersymmetric, it is not completely destroyed by collisions. If the domain wall separating the bubbles has higher tension than the BPS bound, it is expelled from the Lambda = 0 bubble and does not alter its long time behavior. If the domain wall saturates the BPS bound, then it stays inside the Lambda = 0 bubble and removes a finite fraction of future infinity. In this case, the crunch singularity is hidden behind the horizon of a stable hyperbolic black hole.

  1. Bubble gate for in-plane flow control.

    Science.gov (United States)

    Oskooei, Ali; Abolhasani, Milad; Günther, Axel

    2013-07-07

    We introduce a miniature gate valve as a readily implementable strategy for actively controlling the flow of liquids on-chip, within a footprint of less than one square millimetre. Bubble gates provide for simple, consistent and scalable control of liquid flow in microchannel networks, are compatible with different bulk microfabrication processes and substrate materials, and require neither electrodes nor moving parts. A bubble gate consists of two microchannel sections: a liquid-filled channel and a gas channel that intercepts the liquid channel to form a T-junction. The open or closed state of a bubble gate is determined by selecting between two distinct gas pressure levels: the lower level corresponds to the "open" state while the higher level corresponds to the "closed" state. During closure, a gas bubble penetrates from the gas channel into the liquid, flanked by a column of equidistantly spaced micropillars on each side, until the flow of liquid is completely obstructed. We fabricated bubble gates using single-layer soft lithographic and bulk silicon micromachining procedures and evaluated their performance with a combination of theory and experimentation. We assessed the dynamic behaviour during more than 300 open-and-close cycles and report the operating pressure envelope for different bubble gate configurations and for the working fluids: de-ionized water, ethanol and a biological buffer. We obtained excellent agreement between the experimentally determined bubble gate operational envelope and a theoretical prediction based on static wetting behaviour. We report case studies that serve to illustrate the utility of bubble gates for liquid sampling in single and multi-layer microfluidic devices. Scalability of our strategy was demonstrated by simultaneously addressing 128 bubble gates.

  2. Bubbles in Titan’s Seas: Nucleation, Growth, and RADAR Signature

    Science.gov (United States)

    Cordier, Daniel; Liger-Belair, Gérard

    2018-05-01

    In the polar regions of Titan, the main satellite of Saturn, hydrocarbon seas have been discovered by the Cassini–Huygens mission. RADAR observations have revealed surprising and transient bright areas over the Ligeia Mare surface. As suggested by recent research, bubbles could explain these strange features. However, the nucleation and growth of such bubbles, together with their RADAR reflectivity, have never been investigated. All of these aspects are critical to an actual observation. We have thus applied the classical nucleation theory to our context, and we developed a specific radiative transfer model that is appropriate for bubble streams in cryogenic liquids. According to our results, the sea bed appears to be the most plausible place for the generation of bubbles, leading to a signal comparable to observations. This conclusion is supported by thermodynamic arguments and by RADAR properties of a bubbly column. The latter are also valid in the case of bubble plumes, due to gas leaking from the sea floor.

  3. Study on gas-liquid loop reactors with annular bubbling

    International Nuclear Information System (INIS)

    Fei, L.M.; Wang, S.X.; Wu, X.Q.; Lu, D.W.

    1987-01-01

    Bubbling column with draft tube is one of nearly developed reactor. On the background of hydrocarbon oxidations and biochemical engineerings, it has been widely used in chemical industry due to the well characteristics of mass and heat transfer. In this paper, the characteristics of fluid flow, such as gas hold-up, backmixing and mass transfer referred to the liquid volume were measured in a gas-liquid loop reactor with annular bubbling. Different materials - water, alcohol and oi l- were used in the study in measuring the gas hold-up in the annular of the reactor

  4. Modeling quiescent phase transport of air bubbles induced by breaking waves

    Science.gov (United States)

    Shi, Fengyan; Kirby, James T.; Ma, Gangfeng

    Simultaneous modeling of both the acoustic phase and quiescent phase of breaking wave-induced air bubbles involves a large range of length scales from microns to meters and time scales from milliseconds to seconds, and thus is computational unaffordable in a surfzone-scale computational domain. In this study, we use an air bubble entrainment formula in a two-fluid model to predict air bubble evolution in the quiescent phase in a breaking wave event. The breaking wave-induced air bubble entrainment is formulated by connecting the shear production at the air-water interface and the bubble number intensity with a certain bubble size spectra observed in laboratory experiments. A two-fluid model is developed based on the partial differential equations of the gas-liquid mixture phase and the continuum bubble phase, which has multiple size bubble groups representing a polydisperse bubble population. An enhanced 2-DV VOF (Volume of Fluid) model with a k - ɛ turbulence closure is used to model the mixture phase. The bubble phase is governed by the advection-diffusion equations of the gas molar concentration and bubble intensity for groups of bubbles with different sizes. The model is used to simulate air bubble plumes measured in laboratory experiments. Numerical results indicate that, with an appropriate parameter in the air entrainment formula, the model is able to predict the main features of bubbly flows as evidenced by reasonable agreement with measured void fraction. Bubbles larger than an intermediate radius of O(1 mm) make a major contribution to void fraction in the near-crest region. Smaller bubbles tend to penetrate deeper and stay longer in the water column, resulting in significant contribution to the cross-sectional area of the bubble cloud. An underprediction of void fraction is found at the beginning of wave breaking when large air pockets take place. The core region of high void fraction predicted by the model is dislocated due to use of the shear

  5. Bubble fusion: Preliminary estimates

    International Nuclear Information System (INIS)

    Krakowski, R.A.

    1995-01-01

    The collapse of a gas-filled bubble in disequilibrium (i.e., internal pressure much-lt external pressure) can occur with a significant focusing of energy onto the entrapped gas in the form of pressure-volume work and/or acoustical shocks; the resulting heating can be sufficient to cause ionization and the emission of atomic radiations. The suggestion that extreme conditions necessary for thermonuclear fusion to occur may be possible has been examined parametrically in terms of the ratio of initial bubble pressure relative to that required for equilibrium. In this sense, the disequilibrium bubble is viewed as a three-dimensional ''sling shot'' that is ''loaded'' to an extent allowed by the maximum level of disequilibrium that can stably be achieved. Values of this disequilibrium ratio in the range 10 -5 --10 -6 are predicted by an idealized bubble-dynamics model as necessary to achieve conditions where nuclear fusion of deuterium-tritium might be observed. Harmonic and aharmonic pressurizations/decompressions are examined as means to achieve the required levels of disequilibrium required to create fusion conditions. A number of phenomena not included in the analysis reported herein could enhance or reduce the small levels of nuclear fusions predicted

  6. Critical scattering by bubbles

    International Nuclear Information System (INIS)

    Fiedler-Ferrari, N.; Nussenzveig, H.M.

    1986-11-01

    We apply the complex angular momentum theory to the problem of the critical scattering of light by spherical cavities in the high frequency limit (permittivity greater than the external media) (e.g, air bubble in water) (M.W.O.) [pt

  7. Heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The CERN Heavy liquid bubble chamber being installed in the north experimental hall at the PS. On the left, the 1180 litre body; in the centre the magnet, which can produce a field of 26 800 gauss; on the right the expansion mechanism.

  8. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  9. BEBC bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  10. The effect of bubbling regime on gas and liquid phase mixing in bubble column reactors

    Czech Academy of Sciences Publication Activity Database

    Zahradník, Jindřich; Fialová, Marie

    1996-01-01

    Roč. 51, č. 10 (1996), s. 2491-2500 ISSN 0009-2509. [International Symposium on Chemical Reaction Engineering ISCRE /14./. Brugge, 05.05.1996-08.05.1996] Grant - others:Copernicus(XE) CIPA-CT94-0179 Impact factor: 1.405, year: 1996

  11. Ensemble correlation PIV applied to bubble plumes rising in a bubble column.

    NARCIS (Netherlands)

    Delnoij, E.; Westerweel, J.; Deen, N.G.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1999-01-01

    This paper discusses an ensemble correlation, double-exposure single-frame, particle image velocimetry (PIV) technique that can be applied to study dispersed gas¿liquid two-phase flows. The essentials of this technique will be reviewed and several important issues concerning the implementation of

  12. Bubble dynamics and bubble-induced turbulence of a single-bubble chain

    Science.gov (United States)

    Lee, Joohyoung; Park, Hyungmin

    2016-11-01

    In the present study, the bubble dynamics and liquid-phase turbulence induced by a chain of bubbles injected from a single nozzle have been experimentally investigated. Using a high-speed two-phase particle image velociemtry, measurements on the bubbles and liquid-phase velocity field are conducted in a transparent tank filled with water, while varying the bubble release frequency from 0.1 to 35 Hz. The tested bubble size ranges between 2.0-3.2 mm, and the corresponding bubble Reynolds number is 590-1100, indicating that it belongs to the regime of path instability. As the release frequency increases, it is found that the global shape of bubble dispersion can be classified into two regimes: from asymmetric (regular) to axisymmetric (irregular). In particular, at higher frequency, the wake vortices of leading bubbles cause an irregular behaviour of the following bubble. For the liquid phase, it is found that a specific trend on the bubble-induced turbulence appears in a strong relation to the above bubble dynamics. Considering this, we try to provide a theoretical model to estimate the liquid-phase turbulence induced by a chain of bubbles. Supported by a Grant funded by Samsung Electronics, Korea.

  13. Characteristics of bubble plumes, bubble-plume bubbles and waves from wind-steepened wave breaking

    NARCIS (Netherlands)

    Leifer, I.; Caulliez, G.; Leeuw, G. de

    2007-01-01

    Observations of breaking waves, associated bubble plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened

  14. Bubbles generated from wind-steepened breaking waves: 1. Bubble plume bubbles

    NARCIS (Netherlands)

    Leifer, I.; Leeuw, G. de

    2006-01-01

    Measurements of bubble plumes from paddle-amplified, wind stress breaking waves were made in a large wind-wave channel during the LUMINY experiment in fresh (but not clean) water. Bubble plumes exhibited considerable variability with respect to dynamics, bubble size distribution, and physical

  15. Bubble Dynamics and Shock Waves

    CERN Document Server

    2013-01-01

    This volume of the Shock Wave Science and Technology Reference Library is concerned with the interplay between bubble dynamics and shock waves. It is divided into four parts containing twelve chapters written by eminent scientists. Topics discussed include shock wave emission by laser generated bubbles (W Lauterborn, A Vogel), pulsating bubbles near boundaries (DM Leppinen, QX Wang, JR Blake), interaction of shock waves with bubble clouds (CD Ohl, SW Ohl), shock propagation in polydispersed bubbly liquids by model equations (K Ando, T Colonius, CE Brennen. T Yano, T Kanagawa,  M Watanabe, S Fujikawa) and by DNS (G Tryggvason, S Dabiri), shocks in cavitating flows (NA Adams, SJ Schmidt, CF Delale, GH Schnerr, S Pasinlioglu) together with applications involving encapsulated bubble dynamics in imaging (AA Doinikov, A Novell, JM Escoffre, A Bouakaz),  shock wave lithotripsy (P Zhong), sterilization of ships’ ballast water (A Abe, H Mimura) and bubbly flow model of volcano eruptions ((VK Kedrinskii, K Takayama...

  16. Methane Bubbles Transport Particles From Contaminated Sediment to a Lake Surface

    Science.gov (United States)

    Delwiche, K.; Hemond, H.

    2017-12-01

    Methane bubbling from aquatic sediments has long been known to transport carbon to the atmosphere, but new evidence presented here suggests that methane bubbles also transport particulate matter to a lake surface. This transport pathway is of particular importance in lakes with contaminated sediments, as bubble transport could increase human exposure to toxic metals. The Upper Mystic Lake in Arlington, MA has a documented history of methane bubbling and sediment contamination by arsenic and other heavy metals, and we have conducted laboratory and field studies demonstrating that methane bubbles are capable of transporting sediment particles over depths as great as 15 m in Upper Mystic Lake. Methane bubble traps were used in-situ to capture particles adhered to bubble interfaces, and to relate particle mass transport to bubble flux. Laboratory studies were conducted in a custom-made 15 m tall water column to quantify the relationship between water column height and the mass of particulate transport. We then couple this particle transport data with historical estimates of ebullition from Upper Mystic Lake to quantify the significance of bubble-mediated particle transport to heavy metal cycling within the lake. Results suggest that methane bubbles can represent a significant pathway for contaminated sediment to reach surface waters even in relatively deep water bodies. Given the frequent co-occurrence of contaminated sediments and high bubble flux rates, and the potential for human exposure to heavy metals, it will be critical to study the significance of this transport pathway for a range of sediment and contaminant types.

  17. Diagnostic-Photographic Determination of Drag/Lift/Torque Coefficients of High Speed Rigid Body in Water Column

    National Research Council Canada - National Science Library

    Chu, Peter C; Fan, Chenwu; Gefken, Paul R

    2008-01-01

    Prediction of rigid body falling through water column with a high speed (such as Mk-84 bomb) needs formulas for drag/lift and torque coefficients, which depend on various physical processes such as supercavitation and bubbles...

  18. Modeling Stone Columns.

    Science.gov (United States)

    Castro, Jorge

    2017-07-11

    This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the "unit cell", longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

  19. Constrained Vapor Bubble Experiment

    Science.gov (United States)

    Gokhale, Shripad; Plawsky, Joel; Wayner, Peter C., Jr.; Zheng, Ling; Wang, Ying-Xi

    2002-11-01

    Microgravity experiments on the Constrained Vapor Bubble Heat Exchanger, CVB, are being developed for the International Space Station. In particular, we present results of a precursory experimental and theoretical study of the vertical Constrained Vapor Bubble in the Earth's environment. A novel non-isothermal experimental setup was designed and built to study the transport processes in an ethanol/quartz vertical CVB system. Temperature profiles were measured using an in situ PC (personal computer)-based LabView data acquisition system via thermocouples. Film thickness profiles were measured using interferometry. A theoretical model was developed to predict the curvature profile of the stable film in the evaporator. The concept of the total amount of evaporation, which can be obtained directly by integrating the experimental temperature profile, was introduced. Experimentally measured curvature profiles are in good agreement with modeling results. For microgravity conditions, an analytical expression, which reveals an inherent relation between temperature and curvature profiles, was derived.

  20. Bubble dynamics in drinks

    Directory of Open Access Journals (Sweden)

    Broučková Zuzana

    2014-03-01

    Full Text Available This study introduces two physical effects known from beverages: the effect of sinking bubbles and the hot chocolate sound effect. The paper presents two simple „kitchen” experiments. The first and second effects are indicated by means of a flow visualization and microphone measurement, respectively. To quantify the second (acoustic effect, sound records are analyzed using time-frequency signal processing, and the obtained power spectra and spectrograms are discussed.

  1. Bubble dynamics in drinks

    Science.gov (United States)

    Broučková, Zuzana; Trávníček, Zdeněk; Šafařík, Pavel

    2014-03-01

    This study introduces two physical effects known from beverages: the effect of sinking bubbles and the hot chocolate sound effect. The paper presents two simple "kitchen" experiments. The first and second effects are indicated by means of a flow visualization and microphone measurement, respectively. To quantify the second (acoustic) effect, sound records are analyzed using time-frequency signal processing, and the obtained power spectra and spectrograms are discussed.

  2. Dynamic simulation of gas-liquid two-phase flow : effect of column aspect ratio on the flow structure

    NARCIS (Netherlands)

    Delnoij, E.; Kuipers, J.A.M.; van Swaaij, W.P.M.

    1997-01-01

    In this paper an Eulerian/Lagrangian model, describing the hydrodynamics of a gas-liquid bubble column, is presented. The model resolves the time dependent, two-dimensional motion of small, spherical gas bubbles in a liquid using the equation of motion. The model incorporates all relevant forces

  3. Dynamic simulation of gas-liquid two-phase flow: effect of column aspect ratio on the flow structure.

    NARCIS (Netherlands)

    Delnoij, E.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1997-01-01

    In this paper an Eulerian/Lagrangian model, describing the hydrodynamics of a gas-liquid bubble column, is presented. The model resolves the time dependent, two-dimensional motion of small, spherical gas bubbles in a liquid using the equation of motion. The model incorporates all relevant forces

  4. Methane rising from the Deep: Hydrates, Bubbles, Oil Spills, and Global Warming

    Science.gov (United States)

    Leifer, I.; Rehder, G. J.; Solomon, E. A.; Kastner, M.; Asper, V. L.; Joye, S. B.

    2011-12-01

    Elevated methane concentrations in near-surface waters and the atmosphere have been reported for seepage from depths of nearly 1 km at the Gulf of Mexico hydrate observatory (MC118), suggesting that for some methane sources, deepsea methane is not trapped and can contribute to atmospheric greenhouse gas budgets. Ebullition is key with important sensitivity to the formation of hydrate skins and oil coatings, high-pressure solubility, bubble size and bubble plume processes. Bubble ROV tracking studies showed survival to near thermocline depths. Studies with a numerical bubble propagation model demonstrated that consideration of structure I hydrate skins transported most methane only to mid-water column depths. Instead, consideration of structure II hydrates, which are stable to far shallower depths and appropriate for natural gas mixtures, allows bubbles to survive to far shallower depths. Moreover, model predictions of vertical methane and alkane profiles and bubble size evolution were in better agreement with observations after consideration of structure II hydrate properties as well as an improved implementation of plume properties, such as currents. These results demonstrate the importance of correctly incorporating bubble hydrate processes in efforts to predict the impact of deepsea seepage as well as to understand the fate of bubble-transported oil and methane from deepsea pipeline leaks and well blowouts. Application to the DWH spill demonstrated the importance of deepsea processes to the fate of spilled subsurface oil. Because several of these parameters vary temporally (bubble flux, currents, temperature), sensitivity studies indicate the importance of real-time monitoring data.

  5. Tools for Reactive Distillation Column Design: Graphical and Stage-to-Stage Computation Methods

    DEFF Research Database (Denmark)

    Sanchez Daza, O.; Cisneros, Eduardo Salvador P.; Hostrup, Martin

    2001-01-01

    Based on the element mass balance concept, a graphical design method and a stage-to-stage multicomponent design method for reactive distillation columns have been developed. For distillation columns comprising reactive and non-reactive stages, a simple design strategy based on reactive and non......-reactive bubble point calculations is proposed. This strategy tracks the conversion and temperature between the feed and the end stages of the column. An illustrative example highlights the verification of the design strategy through rigorous simulation....

  6. Influence of Bubble-Bubble interactions on the macroscale circulation patterns in a bubbling gas-solid fluidized bed

    NARCIS (Netherlands)

    Laverman, J.A.; van Sint Annaland, M.; Kuipers, J.A.M.

    2007-01-01

    The macro-scale circulation patterns in the emulsion phase of a gas-solid fluidized bed in the bubbling regime have been studied with a 3D Discrete Bubble Model. It has been shown that bubble-bubble interactions strongly influence the extent of the solids circulation and the bubble size

  7. ( Anogeissus leiocarpus ) timber columns

    African Journals Online (AJOL)

    A procedure for designing axially loaded Ayin (Anogeissus leiocarpus) wood column or strut has been investigated. Instead of the usual categorization of columns into short, intermediate and slender according to the value of slenderness ratio, a continuous column formula representing the three categories was derived.

  8. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  9. Well-posed Euler model of shock-induced two-phase flow in bubbly liquid

    Science.gov (United States)

    Tukhvatullina, R. R.; Frolov, S. M.

    2018-03-01

    A well-posed mathematical model of non-isothermal two-phase two-velocity flow of bubbly liquid is proposed. The model is based on the two-phase Euler equations with the introduction of an additional pressure at the gas bubble surface, which ensures the well-posedness of the Cauchy problem for a system of governing equations with homogeneous initial conditions, and the Rayleigh-Plesset equation for radial pulsations of gas bubbles. The applicability conditions of the model are formulated. The model is validated by comparing one-dimensional calculations of shock wave propagation in liquids with gas bubbles with a gas volume fraction of 0.005-0.3 with experimental data. The model is shown to provide satisfactory results for the shock propagation velocity, pressure profiles, and the shock-induced motion of the bubbly liquid column.

  10. Cost-benefit of the bubble tower concept as a containment passive safety system

    International Nuclear Information System (INIS)

    Iotti, R.C.; Bardach, H.; Shin, J.J.; Parnes, M.J.

    1994-01-01

    Containment system integrity for both PWRs and BWRs can be assured by passive measures highlighted the use of an accessory Bubble Tower. The utilization of the Bubble Tower precludes the possibility of containment overpressurization. From the thermodynamic standpoint, the Bubble Tower is simply water column of about 120 ft. height attached to the containment and connected to the air space above the suppression pool of a BWR, or a PWR In-containment Refueling Water Storage Tank. From the radiological protection standpoint, the Bubble Tower is a water column sufficient to effect decontamination factors of at least 100 for nuclide species other than the noble gases, and with the addition of organic solubilizers sufficient to effect decontamination factors of at least 10 iodides and at least 100 for other nuclide species. When containment steam or noncondensable gas passes through the Bubble Tower, a significant fraction of the radionuclides is absorbed by the water column. When a cost-benefit dose evaluation is performed relative to the utilization of a Bubble Tower, even under conditions where the dollars per man-rem is taken as $1000, the results are favorable. They are substantially more favorable when the dollars per man-rem is taken as $5000 or $10,000 as are the current trends. (author)

  11. Mass transfer in a bubble column discrete bubble modeling of CO2 absorption in a NaOH solution in a micro-Structured Bubble Column

    NARCIS (Netherlands)

    Jain, D.; Kuipers, J.A.M.; Deen, N.G.

    2015-01-01

    Gas-liquid-solid reactive flows are encountered in many industrial processes. While the transport of reactants and chemical reaction is between gas and liquid phase, solid particles are introduced as catalysts to facilitate the reaction. Major industrial processes where such flows are encountered

  12. Layered storage of biogenic methane-enriched gas bubbles in peat: A lumped capacitance model controlled by soil structure

    Science.gov (United States)

    Chen, X.; Comas, X.; Binley, A. M.; Slater, L. D.

    2017-12-01

    Methane can accumulate in the gaseous phase in peats, and enter the atmosphere as gas bubbles with a mass flux higher than that via diffusion and plant-mediated pathways. A complete understanding of the mechanisms regulating bubble storage in peats remains incomplete. We developed a layered model to quantify the storage of gas bubbles over a peat column based on a general lumped capacitance model. This conceptual model was applied to explain the effects of peat structure on bubble storage at different depths observed in a laboratory experiment. A peat monolith was collected from the Everglades, a subtropical wetland located in Florida (USA), and kept submerged in a cuboid chamber over 102 days until gas bubble saturation was achieved. Time-lapse ground-penetrating radar (GPR) was used to estimate changes in gas content of each layer and the corresponding average dimensions of stored gas bubbles. The results highlight a hotspot layer of bubble accumulation at depths between 5 and 10 cm below the monolith surface. Bubbles in this shallow hotspot layer were larger relative to those in deeper layers, whilst the degree of decomposition of the upper layers was generally smaller than that of the lower layers based on von Post humification tests. X-ray Computer tomography (CT) was applied to resin-impregnated peat sections from different depths and the results showed that a higher porosity promotes bubbles storage. The stored gas bubbles were released by changing water levels and the air CH4 concentrations above the peat monolith were measured using a flow-through chamber system to confirm the high CH4 concentration in the stored bubbles. Our findings suggest that bubble capacitance is related to the difference in size between gas bubbles and peat pores. This work has implications for better understanding how changes in water table elevation associated with climate change and sea level rise (particularly for freshwater wetlands near coastal areas like the Everglades) may

  13. Rational Asset Pricing Bubbles Revisited

    OpenAIRE

    Jan Werner

    2012-01-01

    Price bubble arises when the price of an asset exceeds the asset's fundamental value, that is, the present value of future dividend payments. The important result of Santos and Woodford (1997) says that price bubbles cannot exist in equilibrium in the standard dynamic asset pricing model with rational agents as long as assets are in strictly positive supply and the present value of total future resources is finite. This paper explores the possibility of asset price bubbles when either one of ...

  14. Droplets, Bubbles and Ultrasound Interactions.

    Science.gov (United States)

    Shpak, Oleksandr; Verweij, Martin; de Jong, Nico; Versluis, Michel

    2016-01-01

    The interaction of droplets and bubbles with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to circulate within blood vessels. Perfluorocarbon liquid droplets can be a potential new generation of microbubble agents as ultrasound can trigger their conversion into gas bubbles. Prior to activation, they are at least five times smaller in diameter than the resulting bubbles. Together with the violent nature of the phase-transition, the droplets can be used for local drug delivery, embolotherapy, HIFU enhancement and tumor imaging. Here we explain the basics of bubble dynamics, described by the Rayleigh-Plesset equation, bubble resonance frequency, damping and quality factor. We show the elegant calculation of the above characteristics for the case of small amplitude oscillations by linearizing the equations. The effect and importance of a bubble coating and effective surface tension are also discussed. We give the main characteristics of the power spectrum of bubble oscillations. Preceding bubble dynamics, ultrasound propagation is introduced. We explain the speed of sound, nonlinearity and attenuation terms. We examine bubble ultrasound scattering and how it depends on the wave-shape of the incident wave. Finally, we introduce droplet interaction with ultrasound. We elucidate the ultrasound-focusing concept within a droplets sphere, droplet shaking due to media compressibility and droplet phase-conversion dynamics.

  15. Helium bubble bursting in tungsten

    International Nuclear Information System (INIS)

    Sefta, Faiza; Juslin, Niklas; Wirth, Brian D.

    2013-01-01

    Molecular dynamics simulations have been used to systematically study the pressure evolution and bursting behavior of sub-surface helium bubbles and the resulting tungsten surface morphology. This study specifically investigates how bubble shape and size, temperature, tungsten surface orientation, and ligament thickness above the bubble influence bubble stability and surface evolution. The tungsten surface is roughened by a combination of adatom “islands,” craters, and pinholes. The present study provides insight into the mechanisms and conditions leading to various tungsten topology changes, which we believe are the initial stages of surface evolution leading to the formation of nanoscale fuzz

  16. Bubble Coalescence: Effect of Bubble Approach Velocity and Liquid Viscosity

    Czech Academy of Sciences Publication Activity Database

    Orvalho, Sandra; Růžička, Marek; Olivieri, G.; Marzocchella, A.

    2015-01-01

    Roč. 134, SEP 29 (2015), s. 205-216 ISSN 0009-2509 R&D Projects: GA MŠk(CZ) LD13018 Institutional support: RVO:67985858 Keywords : bubble coalescence * bubble approach velocity * liquid viscosity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.750, year: 2015

  17. Understanding the bubbles

    DEFF Research Database (Denmark)

    Turcan, Romeo V.

    that are identified to exist between the Internet and housing market bubbles: uncertainty and sentiments. The iteration between uncertainty and sentiments leads to the emergence of the third commonality: residue. The residue is the difference between the actors’ overall sentiment about exaggerated future prospects...... all boils down to the role pricing plays vis-à-vis the emergence of a new venture and its perceived value. Being in the midst of the global economic crisis provides us with a unique opportunity to refine the proposed model, especially by understanding its temporal and contextual boundaries....

  18. Visualization of airflow growing soap bubbles

    Science.gov (United States)

    Al Rahbi, Hamood; Bock, Matthew; Ryu, Sangjin

    2016-11-01

    Visualizing airflow inside growing soap bubbles can answer questions regarding the fluid dynamics of soap bubble blowing, which is a model system for flows with a gas-liquid-gas interface. Also, understanding the soap bubble blowing process is practical because it can contribute to controlling industrial processes similar to soap bubble blowing. In this study, we visualized airflow which grows soap bubbles using the smoke wire technique to understand how airflow blows soap bubbles. The soap bubble blower setup was built to mimic the human blowing process of soap bubbles, which consists of a blower, a nozzle and a bubble ring. The smoke wire was placed between the nozzle and the bubble ring, and smoke-visualized airflow was captured using a high speed camera. Our visualization shows how air jet flows into the growing soap bubble on the ring and how the airflow interacts with the soap film of growing bubble.

  19. Bubble levitation and translation under single-bubble sonoluminescence conditions.

    Science.gov (United States)

    Matula, Thomas J

    2003-08-01

    Bubble levitation in an acoustic standing wave is re-examined for conditions relevant to single-bubble sonoluminescence. Unlike a previous examination [Matula et al., J. Acoust. Soc. Am. 102, 1522-1527 (1997)], the stable parameter space [Pa,R0] is accounted for in this realization. Forces such as the added mass force and drag are included, and the results are compared with a simple force balance that equates the Bjerknes force to the buoyancy force. Under normal sonoluminescence conditions, the comparison is quite favorable. A more complete accounting of the forces shows that a stably levitated bubble does undergo periodic translational motion. The asymmetries associated with translational motion are hypothesized to generate instabilities in the spherical shape of the bubble. A reduction in gravity results in reduced translational motion. It is hypothesized that such conditions may lead to increased light output from sonoluminescing bubbles.

  20. New mechanism for bubble nucleation: Classical transitions

    International Nuclear Information System (INIS)

    Easther, Richard; Giblin, John T. Jr; Hui Lam; Lim, Eugene A.

    2009-01-01

    Given a scalar field with metastable minima, bubbles nucleate quantum mechanically. When bubbles collide, energy stored in the bubble walls is converted into kinetic energy of the field. This kinetic energy can facilitate the classical nucleation of new bubbles in minima that lie below those of the 'parent' bubbles. This process is efficient and classical, and changes the dynamics and statistics of bubble formation in models with multiple vacua, relative to that derived from quantum tunneling.

  1. Experimental investigation of the hydrodynamics of confined bubble plumes in water and viscous media

    International Nuclear Information System (INIS)

    Brahma N Reddy Vanga; Martin A Lopez de Bertodano; Alexandr Zaruba; Eckhard Krepper; Horst-Michael Prasser

    2005-01-01

    Wire-mesh tomography measurements of void fraction and bubble size distribution in a rectangular bubble column 10 cm wide and 2 cm deep have been conducted. Experiments were performed in an air-water and ethylene glycol system with the column operating in the dispersed bubbly flow regime.Experiments were conducted for plumes with different aspect ratios between 2.2 to 13. The experiments also serve the purpose of studying the performance of wire-mesh sensors in batch flows. The behaviour of the long plumes (larger aspect ratio) was found to be significantly different than that of the short plumes (aspect ratios 2 to 4). The oscillating nature of the bubble plume is preserved over the entire height of the water column for the short plumes. The longer plumes are characterized by two distinct regions, the near injector oscillating region and a further downstream region where the bubbles rise in a string like motion. The void fraction distribution in the oscillating region of the plume exhibits a center-peak profile. A 'wall peak' has been observed in the measured void fraction profiles (for higher gas flow rates) in the downstream string-like region. The effect of column height and superficial gas velocity on the void distribution has been investigated. This paper presents the measurement principle and the experimental results for short and long plumes in an air-water system and for short plumes rising in viscous media. The results of the visualization experiment characterizing the structure of the bubble plume and the oscillation frequency of the bubble plumes are reported. (authors)

  2. Blistering and bubble formation

    International Nuclear Information System (INIS)

    Roth, J.

    1976-01-01

    Blister formation in metals has been observed during bombardment with inert-gas ions in the energy range between 1 and 2000 keV at doses of about 10 17 to 10 19 cm -2 . The changes in surface topography and the erosion yields were mainly studied in the scanning electron microscope (SEM). Additionally the release of the implanted gas during blister formation was observed. Recently measurements on single crystals were performed determining simultaneously the implantation profile, the total amount of trapped ions, the depth distribution of the induced lattice damage and the thickness of the covers of the blisters. In several stages of the formation process of blisters the implanted layer was observed in the transmission electron microscope (TEM) showing the formation of gas bubbles. Using the results of all these measurements in this review an attempt is made to develop a model of blister formation combining the effects of hydrostatic pressure in the gas bubbles and lateral stress due to volume swelling. (author)

  3. Sonoluminescing Air Bubbles Rectify Argon

    NARCIS (Netherlands)

    Lohse, Detlef; Brenner, Michael P.; Dupont, Todd F.; Hilgenfeldt, Sascha; Johnston, Blaine

    1997-01-01

    The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the percentage of inert gas within the bubble. We propose a theory for this dependence, based on a combination of principles from sonochemistry and hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent

  4. Bubble coalescence in breathing DNA

    DEFF Research Database (Denmark)

    Novotný, Tomas; Pedersen, Jonas Nyvold; Ambjörnsson, Tobias

    2007-01-01

    We investigate the coalescence of two DNA bubbles initially located at weak segments and separated by a more stable barrier region in a designed construct of double-stranded DNA. The characteristic time for bubble coalescence and the corresponding distribution are derived, as well as the distribu...... vicious walkers in opposite potentials....

  5. A prediction for bubbling geometries

    OpenAIRE

    Okuda, Takuya

    2007-01-01

    We study the supersymmetric circular Wilson loops in N=4 Yang-Mills theory. Their vacuum expectation values are computed in the parameter region that admits smooth bubbling geometry duals. The results are a prediction for the supergravity action evaluated on the bubbling geometries for Wilson loops.

  6. Preparation of bubble damage detectors

    International Nuclear Information System (INIS)

    Tu Caiqing; Guo Shilun; Wang Yulan; Hao Xiuhong; Chen Changmao; Su Jingling

    1997-01-01

    Bubble damage detectors have been prepared by using polyacrylamide as detector solid and freon as detector liquid. Tests show that the prepared detectors are sensitive to fast neutrons and have proportionality between bubble number and neutron fluence within a certain range of neutron fluence. Therefore, it can be used as a fast neutron detector and a dosimeter

  7. The little holographic bubble chambers

    International Nuclear Information System (INIS)

    Herve, A.

    1983-01-01

    The lifetime study of the charmed particles has readvanced the idea to use holography for the little fast-cycle bubble chambers. A pilot experiment has been realised in 1982 with a little bubble chamber filled up with freon-115. 40000 holograms have been recorded [fr

  8. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  9. Picobubble column flotation of fine coal

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; Samuel Yu; Xiaohua Zhou; R.Q. Honaker; B.K. Parekh [University of Kentucky, Lexington, KY (United States). Department of Mining Engineering

    2008-01-15

    Froth flotation is widely used in the coal industry to clean -28 mesh (0.6 mm) or -100 mesh (0.15 mm) fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range, nominally 10-100 {mu}m, beyond which the flotation efficiency drops sharply. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. Experimental results have shown that the use of picobubbles in a 5-cm diameter column flotation increased the combustible recovery of a highly floatable coal by up to 10% and that of a poorly floatable coal by up to 40%, depending on the feed rate, collector dosage, and other flotation conditions. 14 refs.

  10. Sinking bubbles in stout beers

    Science.gov (United States)

    Lee, W. T.; Kaar, S.; O'Brien, S. B. G.

    2018-04-01

    A surprising phenomenon witnessed by many is the sinking bubbles seen in a settling pint of stout beer. Bubbles are less dense than the surrounding fluid so how does this happen? Previous work has shown that the explanation lies in a circulation of fluid promoted by the tilted sides of the glass. However, this work has relied heavily on computational fluid dynamics (CFD) simulations. Here, we show that the phenomenon of sinking bubbles can be predicted using a simple analytic model. To make the model analytically tractable, we work in the limit of small bubbles and consider a simplified geometry. The model confirms both the existence of sinking bubbles and the previously proposed mechanism.

  11. Small Column Ion Exchange

    International Nuclear Information System (INIS)

    Huff, Thomas

    2010-01-01

    Small Column Ion Exchange (SCIX) leverages a suite of technologies developed by DOE across the complex to achieve lifecycle savings. Technologies are applicable to multiple sites. Early testing supported multiple sites. Balance of SRS SCIX testing supports SRS deployment. A forma Systems Engineering Evaluation (SEE) was performed and selected Small Column Ion Exchange columns containing Crystalline Silicotitanate (CST) in a 2-column lead/lag configuration. SEE considered use of Spherical Resorcinol-Formaldehyde (sRF). Advantages of approach at SRS include: (1) no new buildings, (2) low volume of Cs waste in solid form compared to aqueous strip effluent; and availability of downstream processing facilities for immediate processing of spent resin.

  12. Air column in esophagus and symptoms of gastroesophageal reflux disease

    International Nuclear Information System (INIS)

    Moosavi, Alijavad; Raji, Hanieh; Teimoori, Mojtaba; Ghourchian, Shadi

    2012-01-01

    During imaging of the normal esophagus, air is often detected. The purpose of this study was to determine the correlation between the appearance of air bubbles on imaging and Gastroesophageal Reflux Disease (GERD) symptoms. The cross-sectional imaging study was conducted at Rasole Akram Hospital, Tehran, Iran. A total of 44 patients underwent X-ray computed tomography (CT) scanning; the presence of air in the esophagus and visible on CT imaging was scrutinized. The average age of the subjects was 59 and the male to female ratio was 0.83. We found a significant relationship between the presence of GERD symptoms, the size of air bubbles and esophageal dilation (ED) on the CT scan. Air bubbles in the esophagus may be seen frequently in CT scans, but their size and location can vary. The GERD symptoms can arise when a small diameter air column is present within the esophagus, especially in the middle and lower parts

  13. Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

    Science.gov (United States)

    Warzinski, Robert P.; Lynn, Ronald; Haljasmaa, Igor; Leifer, Ira; Shaffer, Frank; Anderson, Brian J.; Levine, Jonathan S.

    2014-10-01

    Predicting the fate of subsea hydrocarbon gases escaping into seawater is complicated by potential formation of hydrate on rising bubbles that can enhance their survival in the water column, allowing gas to reach shallower depths and the atmosphere. The precise nature and influence of hydrate coatings on bubble hydrodynamics and dissolution is largely unknown. Here we present high-definition, experimental observations of complex surficial mechanisms governing methane bubble hydrate formation and dissociation during transit of a simulated oceanic water column that reveal a temporal progression of deep-sea controlling mechanisms. Synergistic feedbacks between bubble hydrodynamics, hydrate morphology, and coverage characteristics were discovered. Morphological changes on the bubble surface appear analogous to macroscale, sea ice processes, presenting new mechanistic insights. An inverse linear relationship between hydrate coverage and bubble dissolution rate is indicated. Understanding and incorporating these phenomena into bubble and bubble plume models will be necessary to accurately predict global greenhouse gas budgets for warming ocean scenarios and hydrocarbon transport from anthropogenic or natural deep-sea eruptions.

  14. JCE Feature Columns

    Science.gov (United States)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  15. Models and observations of foam coverage and bubble content in the surf zone

    Science.gov (United States)

    Kirby, J. T.; Shi, F.; Holman, R. A.

    2010-12-01

    Optical and acoustical observations and communications are hampered in the nearshore by the presence of bubbles and foam generated by breaking waves. Bubble clouds in the water column provide a highly variable (both spatially and temporally) obstacle to direct acoustic and optical paths. Persistent foam riding on the water surface creates a primary occlusion of optical penetration into the water column. In an effort to better understand and predict the level of bubble and foam content in the surfzone, we have been pursuing the development of a detailed phase resolved model of fluid and gaseous components of the water column, using a Navier-Stokes/VOF formulation extended to include a multiphase description of polydisperse bubble populations. This sort of modeling provides a detailed description of large scale turbulent structures and associated bubble transport mechanisms under breaking wave crests. The modeling technique is too computationally intensive, however, to provide a wider-scale description of large surfzone regions. In order to approach the larger scale problem, we are developing a model for spatial and temporal distribution of foam and bubbles within the framework of a Boussinesq model. The basic numerical framework for the code is described by Shi et al (2010, this conference). Bubble effects are incorporated both in the mass and momentum balances for weakly dispersive, fully nonlinear waves, with spatial and temporal bubble distributions parameterized based on the VOF modeling and measurements and tied to the computed rate of dissipation of energy during breaking. A model of a foam layer on the water surface is specified using a shallow water formulation. Foam mass conservation includes source and sink terms representing outgassing of the water column, direct foam generation due to surface agitation, and erosion due to bubble bursting. The foam layer motion in the plane of the water surface arises due to a balance of drag forces due to wind and water

  16. Sonochemistry and the acoustic bubble

    CERN Document Server

    Grieser, Franz; Enomoto, Naoya; Harada, Hisashi; Okitsu, Kenji; Yasui, Kyuichi

    2015-01-01

    Sonochemistry and the Acoustic Bubble provides an introduction to the way ultrasound acts on bubbles in a liquid to cause bubbles to collapse violently, leading to localized 'hot spots' in the liquid with temperatures of 5000° celcius and under pressures of several hundred atmospheres. These extreme conditions produce events such as the emission of light, sonoluminescence, with a lifetime of less than a nanosecond, and free radicals that can initiate a host of varied chemical reactions (sonochemistry) in the liquid, all at room temperature. The physics and chemistry behind the p

  17. Effect of bubble interface parameters on predicted of bubble departure diameter in a narrow channel

    International Nuclear Information System (INIS)

    Xu Jianjun; Xie Tianzhou; Zhou Wenbin; Chen Bingde; Huang Yanping

    2014-01-01

    The predicted model on the bubble departure diameter in a narrow channel is built by analysis of forces acting on the bubble, and effects of bubble interface parameters such as the bubble inclination angle, upstream contact angle, downstream contact angle and bubble contact diameter on predicted bubble departure diameters in a narrow channel are analysed by comparing with the visual experimental data. Based on the above results, the bubble interface parameters as the input parameters used to obtain the bubble departure diameter in a narrow channel are assured, and the bubble departure diameters in a narrow channel are predicted by solving the force equation. The predicted bubble departure diameters are verified by the 58 bubble departure diameters obtained from the vertical and inclined visual experiment, and the predicted results agree with the experimental results. The different forces acting on the bubble are obtained and the effect of thermal parameters in this experiment on bubble departure diameters is analysed. (authors)

  18. New evidence on the first financial bubble

    NARCIS (Netherlands)

    Frehen, R.G.P.; Goetzmann, W.; Rouwenhorst, K.G.

    2013-01-01

    The Mississippi Bubble, South Sea Bubble and the Dutch Windhandel of 1720 together represent the world's first global financial bubble. We hand-collect cross-sectional price data and investor account data from 1720 to test theories about market bubbles. Our tests suggest that innovation was a key

  19. Bubble Formation in Basalt-like Melts

    DEFF Research Database (Denmark)

    Jensen, Martin; Keding, Ralf; Yue, Yuanzheng

    2011-01-01

    and their diameter. The variation in melting temperature has little influence on the overall bubble volume. However, the size distribution of the bubbles varies with the melting temperature. When the melt is slowly cooled, the bubble volume increases, implying decreased solubility of the gaseous species. Mass...... spectroscopy analysis of gases liberated during heating of the glass reveals that small bubbles contain predominantly CH4, CO and CO2, whereas large bubbles bear N2, SO2 and H2S. The methodology utilised in this work can, besides mapping the bubbles in a glass, be applied to shed light on the sources of bubble...

  20. Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2010-11-23

    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  1. Nuclear reactor control column

    International Nuclear Information System (INIS)

    Bachovchin, D.M.

    1982-01-01

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor

  2. Microstreaming from Sessile Semicylindrical Bubbles

    Science.gov (United States)

    Hilgenfeldt, Sascha; Rallabandi, Bhargav; Guo, Lin; Wang, Cheng

    2014-03-01

    Powerful steady streaming flows result from the ultrasonic driving of microbubbles, in particular when these bubbles have semicylindrical cross section and are positioned in contact with a microfluidic channel wall. We have used this streaming in experiment to develop novel methods for trapping and sorting of microparticles by size, as well as for micromixing. Theoretically, we arrive at an analytical description of the streaming flow field through an asymptotic computation that, for the first time, reconciles the boundary layers around the bubble and along the substrate wall, and also takes into account the oscillation modes of the bubble. This approach gives insight into changes in the streaming pattern with bubble size and driving frequency, including a reversal of the flow direction at high frequencies with potentially useful applications. Present address: Mechanical and Aerospace Engineering, Missouri S &T.

  3. Electroweak bubble wall speed limit

    Energy Technology Data Exchange (ETDEWEB)

    Bödeker, Dietrich [Fakultät für Physik, Universität Bielefeld, 33501 Bielefeld (Germany); Moore, Guy D., E-mail: bodeker@physik.uni-bielefeld.de, E-mail: guymoore@ikp.physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 2, 64289 Darmstadt (Germany)

    2017-05-01

    In extensions of the Standard Model with extra scalars, the electroweak phase transition can be very strong, and the bubble walls can be highly relativistic. We revisit our previous argument that electroweak bubble walls can 'run away,' that is, achieve extreme ultrarelativistic velocities γ ∼ 10{sup 14}. We show that, when particles cross the bubble wall, they can emit transition radiation. Wall-frame soft processes, though suppressed by a power of the coupling α, have a significance enhanced by the γ-factor of the wall, limiting wall velocities to γ ∼ 1/α. Though the bubble walls can move at almost the speed of light, they carry an infinitesimal share of the plasma's energy.

  4. Holography in small bubble chambers

    International Nuclear Information System (INIS)

    Lecoq, P.

    1984-01-01

    This chapter reports on an experiment to determine the total charm cross section at different incident momenta using the small, heavy liquid bubble chamber HOBC. Holography in liquid hydrogen is also tested using the holographic lexan bubble chamber HOLEBC with the aim of preparing a future holographic experiment in hydrogen. The high intensity tests show that more than 100 incident tracks per hologram do not cause a dramatic effect on the picture quality. Hydrogen is more favorable than freon as the bubble growth is much slower in hydrogen. An advantage of holography is to have the maximum resolution in the full volume of the bubble chamber, which allows a gain in sensitivity by a factor of 10 compared to classical optics as 100 tracks per hologram look reasonable. Holograms are not more difficult to analyze than classical optics high-resolution pictures. The results show that holography is a very powerful technique which can be used in very high resolution particle physics experiments

  5. Improvements in solvent extraction columns

    International Nuclear Information System (INIS)

    Aughwane, K.R.

    1987-01-01

    Solvent extraction columns are used in the reprocessing of irradiated nuclear fuel. For an effective reprocessing operation a solvent extraction column is required which is capable of distributing the feed over most of the column. The patent describes improvements in solvent extractions columns which allows the feed to be distributed over an increased length of column than was previously possible. (U.K.)

  6. Bubbles in a freshwater lake.

    Science.gov (United States)

    Thorpe, S A; Stubbs, A R

    1979-05-31

    WHEN the wind is strong enough to produce whitecaps on Loch Ness, patchy 'clouds' of acoustic reflectors are detected well below the surface, the depth to which they penetrate increasing with wind speed (Fig. 1). No seasonal variation in the occurrence of the reflectors has been detected. A biological explanation is therefore discounted and we suggest here that they are bubbles caused by waves breaking and forming whitecaps in deep water. Similar bubble clouds may occur in other lakes and in the sea.

  7. Slowing down bubbles with sound

    Science.gov (United States)

    Poulain, Cedric; Dangla, Remie; Guinard, Marion

    2009-11-01

    We present experimental evidence that a bubble moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down even for moderate acoustic pressure. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the bubble's fundamental resonant mode. We render the bubble's oscillations and translational movements using high speed video. We show that radial oscillations (Rayleigh-Plesset type) have no effect on the mean velocity, while above a critical pressure, a parametric type instability (Faraday waves) is triggered and gives rise to nonlinear surface oscillations. We evidence that these surface waves are subharmonic and responsible for the bubble's drag increase. When the acoustic intensity is increased, Faraday modes interact and the strongly nonlinear oscillations behave randomly, leading to a random behavior of the bubble's trajectory and consequently to a higher slow down. Our observations may suggest new strategies for bubbly flow control, or two-phase microfluidic devices. It might also be applicable to other elastic objects, such as globules, cells or vesicles, for medical applications such as elasticity-based sorting.

  8. Bubble bursting at an interface

    Science.gov (United States)

    Kulkarni, Varun; Sajjad, Kumayl; Anand, Sushant; Fezzaa, Kamel

    2017-11-01

    Bubble bursting is crucial to understanding the life span of bubbles at an interface and more importantly the nature of interaction between the bulk liquid and the outside environment from the point of view of chemical and biological material transport. The dynamics of the bubble as it rises from inside the liquid bulk to its disappearance on the interface after bursting is an intriguing process, many aspects of which are still being explored. In our study, we make detailed high speed imaging measurements to examine carefully the hole initiation and growth in bursting bubbles that unearth some interesting features of the process. Previous analyses available in literature are revisited based on our novel experimental visualizations. Using a combination of experiments and theory we investigate the role of various forces during the rupturing process. This work aims to further our current knowledge of bubble dynamics at an interface with an aim of predicting better the bubble evolution from its growth to its eventual integration with the liquid bulk.

  9. Measuring online social bubbles

    Directory of Open Access Journals (Sweden)

    Dimitar Nikolov

    2015-12-01

    Full Text Available Social media have become a prevalent channel to access information, spread ideas, and influence opinions. However, it has been suggested that social and algorithmic filtering may cause exposure to less diverse points of view. Here we quantitatively measure this kind of social bias at the collective level by mining a massive datasets of web clicks. Our analysis shows that collectively, people access information from a significantly narrower spectrum of sources through social media and email, compared to a search baseline. The significance of this finding for individual exposure is revealed by investigating the relationship between the diversity of information sources experienced by users at both the collective and individual levels in two datasets where individual users can be analyzed—Twitter posts and search logs. There is a strong correlation between collective and individual diversity, supporting the notion that when we use social media we find ourselves inside “social bubbles.” Our results could lead to a deeper understanding of how technology biases our exposure to new information.

  10. Beyond the gas bubble

    International Nuclear Information System (INIS)

    Hilt, R.H.

    1990-01-01

    The deliverability issue currently being discussed within the natural gas industry involves both near-term and long-term questions. In the near-term, over the next two or three years, it is probable that the natural gas industry will need to mobilize for much greater levels of investment than have been the experience over the past few years. In the longer-term, it is expected that new opportunities for gas will arise as the nation seeks to meet increasing energy requirements within new environmental constraints. Methane for emissions control, CNG vehicles, expanded gas-fired electricity generation, and increased efficiency of traditional energy services are just a few examples. The issues in the longer-term center on the ability of the gas industry to meet increasing supply requirements reliably and at cost-competitive prices for these markets. This paper begins by reviewing the historical situation of gas deliverability that is the capability of the gas producing and transportation portions of the industry. The delivery system's ability to handle shifts in the centers of consumption and production is discussed, with an emphasis on regional problems of gas deliverability and potential bottlenecks. On the production side, the paper reviews the capability and the required investment necessary to handle an orderly transition to a stable supply and demand balance once the elusive bubble had finally disappeared

  11. Buckling of liquid columns

    NARCIS (Netherlands)

    Habibi, M.; Rahmani, Y.; Bonn, D.; Ribe, N.M.

    2010-01-01

    Under appropriate conditions, a column of viscous liquid falling onto a rigid surface undergoes a buckling instability. Here we show experimentally and theoretically that liquid buckling exhibits a hitherto unsuspected complexity involving three different modes—viscous, gravitational, and

  12. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.

    1979-01-01

    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  13. Hydrodynamics in a swarm of rising bubbles; Hydrodynamique d'un essaim de bulles en ascension

    Energy Technology Data Exchange (ETDEWEB)

    Riboux, G

    2007-04-15

    In many applications, bubbles are used to agitate a liquid in order to enhance mixing and transfer. This work is devoted to the study of the hydrodynamics in a stable bubble column. Experimentally, we have determined the properties of the velocity fluctuations inside and behind a homogeneous swarm of rising bubbles for different bubble sizes and gas volume fractions {alpha}: self-similarity in {alpha}{sup 0,4}, spectrum in k{sup -3} and integral length scale controlled by buoyancy. Numerically, we have reproduced these properties by means of large-scale simulations, the bubbles being modeled by volume-forces. This confirms that the dynamics is controlled by wake interactions. (author)

  14. FEASTING BLACK HOLE BLOWS BUBBLES

    Science.gov (United States)

    2002-01-01

    A monstrous black hole's rude table manners include blowing huge bubbles of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this bubble-blowing phase is a short-lived event. The bubble is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter bubble is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the bubbles. The red regions in the picture denote the hot gas

  15. INTERACTIONS OF THE INFRARED BUBBLE N4 WITH ITS SURROUNDINGS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hong-Li; Li, Jin-Zeng; Yuan, Jing-Hua; Huang, Maohai; Huang, Ya-Fang; Zhang, Si-Ju [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Wu, Yuefang [Department of Astronomy, Peking University, 100871 Beijing (China); Liu, Tie [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Dubner, G.; Paron, S.; Ortega, M. E. [1Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA), CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Molinari, Sergio [Istituto di Astrofisica e Planetologia Spaziali—IAPS, Istituto Nazionale di Astrofisica—INAF, via Fosso del Cavaliere 100, I-00133 Roma (Italy); Zavagno, Annie; Samal, Manash R., E-mail: hlliu@nao.cas.cn [Aix Marseille Universit, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France)

    2016-02-10

    The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with H ii regions have been considered to be good samples for investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble N4 around the H ii region G11.898+0.747, analyzing its interaction with its surroundings and star formation histories therein, with the aim of determining the possibility of star formation triggered by the expansion of the bubble. Using Herschel PACS and SPIRE images with a wide wavelength coverage, we reveal the dust properties over the entire bubble. Meanwhile, we are able to identify six dust clumps surrounding the bubble, with a mean size of 0.50 pc, temperature of about 22 K, mean column density of 1.7 × 10{sup 22} cm{sup −2}, mean volume density of about 4.4 × 10{sup 4} cm{sup −3}, and a mean mass of 320 M{sub ⊙}. In addition, from PAH emission seen at 8 μm, free–free emission detected at 20 cm, and a probability density function in special regions, we could identify clear signatures of the influence of the H ii region on the surroundings. There are hints of star formation, though further investigation is required to demonstrate that N4 is the triggering source.

  16. Bubble nucleation in an explosive micro-bubble actuator

    International Nuclear Information System (INIS)

    Van den Broek, D M; Elwenspoek, M

    2008-01-01

    Explosive evaporation occurs when a thin layer of liquid reaches a temperature close to the critical temperature in a very short time. At these temperatures spontaneous nucleation takes place. The nucleated bubbles instantly coalesce forming a vapour film followed by rapid growth due to the pressure impulse. In this paper we take a closer look at the bubble nucleation. The moment of bubble nucleation was determined by both stroboscopic imaging and resistance thermometry. Two nucleation regimes could be distinguished. Several different heater designs were investigated under heat fluxes of hundreds of W mm −2 . A close correspondence between current density in the heater and point of nucleation was found. This results in design rules for effective heaters

  17. Spherical Solutions of an Underwater Explosion Bubble

    Directory of Open Access Journals (Sweden)

    Andrew B. Wardlaw

    1998-01-01

    Full Text Available The evolution of the 1D explosion bubble flow field out to the first bubble minimum is examined in detail using four different models. The most detailed is based on the Euler equations and accounts for the internal bubble fluid motion, while the simplest links a potential water solution to a stationary, Isentropic bubble model. Comparison of the different models with experimental data provides insight into the influence of compressibility and internal bubble dynamics on the behavior of the explosion bubble.

  18. Bifurcation scenarios for bubbling transition.

    Science.gov (United States)

    Zimin, Aleksey V; Hunt, Brian R; Ott, Edward

    2003-01-01

    Dynamical systems with chaos on an invariant submanifold can exhibit a type of behavior called bubbling, whereby a small random or fixed perturbation to the system induces intermittent bursting. The bifurcation to bubbling occurs when a periodic orbit embedded in the chaotic attractor in the invariant manifold becomes unstable to perturbations transverse to the invariant manifold. Generically the periodic orbit can become transversely unstable through a pitchfork, transcritical, period-doubling, or Hopf bifurcation. In this paper a unified treatment of the four types of bubbling bifurcation is presented. Conditions are obtained determining whether the transition to bubbling is soft or hard; that is, whether the maximum burst amplitude varies continuously or discontinuously with variation of the parameter through its critical value. For soft bubbling transitions, the scaling of the maximum burst amplitude with the parameter is derived. For both hard and soft transitions the scaling of the average interburst time with the bifurcation parameter is deduced. Both random (noise) and fixed (mismatch) perturbations are considered. Results of numerical experiments testing our theoretical predictions are presented.

  19. Shock formation within sonoluminescence bubbles

    International Nuclear Information System (INIS)

    Vuong, V.Q.; Szeri, A.J.; Young, D.A.

    1999-01-01

    A strong case has been made by several authors that sharp, spherically symmetric shocks converging on the center of a spherical bubble driven by a strong acoustic field give rise to rapid compression and heating that produces the brief flash of light known as sonoluminescence. The formation of such shocks is considered. It is found that, although at the main collapse the bubble wall does indeed launch an inwardly-traveling compression wave, and although the subsequent reflection of the wave at the bubble center produces a very rapid temperature peak, the wave is prevented from steepening into a sharp shock by an adverse gradient in the sound speed caused by heat transfer. It is shown that the mathematical characteristics of the flow can be prevented from accumulating into a shock front by this adverse sound speed gradient. A range of results is presented for a variety of bubble ambient radii and sound field amplitudes suggested by experiments. The time scale of the peak temperature in the bubble is set by the dynamics of the compression wave: this is typically in the range 100 - 300 ps (FWHM) in concert with recent measurements of the sonoluminescence pulse width. copyright 1999 American Institute of Physics

  20. Assembly for connecting the column ends of two capillary columns

    International Nuclear Information System (INIS)

    Kolb, B.; Auer, M.; Pospisil, P.

    1984-01-01

    In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

  1. Growth process of helium bubbles in aluminium

    International Nuclear Information System (INIS)

    Shiraishi, Haruki; Sakairi, Hideo; Yagi, Eiichi; Karasawa, Takashi; Hashiguti, R.R.

    1975-01-01

    The growth process of helium bubbles in α-particle bombarded pure aluminum during isothermal anneal ranging 200 to 645 0 C and 1 to 100 hr was observed by a transmission electron microscope and the possible growth mechanisms are discussed. The effects of helium concentration and cold work were investigated. The helium bubbles are detectable only at the anneal above 550 0 C in both annealed and cold worked samples. The cold work does not cause any extra coarsening trend of bubbles. The observed types of bubble distribution in the grain interior are divided into two categories, irrespective of helium concentration and cold work; (1) the fine and uniform bubble distribution, in which case the average size is limited to about 200 A or less in diameter even at the anneal just below the melting point, and (2) the coarsened and non-uniform bubble distribution ranging 500 to 4000 A in diameter. The intermediate size bubbles are scarcely found in any cases. In the above fine bubble distribution, the increase of helium concentration by a factor of two increases the density by the same factor of two, but does not change the mean size of bubbles. Corresponding to the above two characteristic bubble distributions, it is concluded that two different mechanisms are operative in this experiment; (1) the growth of bubbles by the Brownian motion, in which the growth rate of bubbles is decreased to almost zero by bubble faceting and this results in the bubble size constancy during the prolonged annealing, and (2) the growth of bubbles by the grain boundary sweep-out mechanism, by which the abrupt coarsening of bubbles is caused. The lack of existence of the intermediate size bubbles is explained in this way. (auth.)

  2. Aspherical bubble dynamics and oscillation times

    Energy Technology Data Exchange (ETDEWEB)

    Godwin, R.P.; Chapyak, E.J. [Los Alamos National Lab., NM (United States); Noack, J.; Vogel, A. [Medizinisches Laserzentrum Luebeck (Germany)

    1999-03-01

    The cavitation bubbles common in laser medicine are rarely perfectly spherical and are often located near tissue boundaries, in vessels, etc., which introduce aspherical dynamics. Here, novel features of aspherical bubble dynamics are explored. Time-resolved experimental photographs and simulations of large aspect ratio (length:diameter {approximately}20) cylindrical bubble dynamics are presented. The experiments and calculations exhibit similar dynamics. A small high-pressure cylindrical bubble initially expands radially with hardly any axial motion. Then, after reaching its maximum volume, a cylindrical bubble collapses along its long axis with relatively little radial motion. The growth-collapse period of these very aspherical bubbles differs only sightly from twice the Rayleigh collapse time for a spherical bubble with an equivalent maximum volume. This fact justifies using the temporal interval between the acoustic signals emitted upon bubble creation and collapse to estimate the maximum bubble volume. As a result, hydrophone measurements can provide an estimate of the bubble energy even for aspherical bubbles. The prolongation of the oscillation period of bubbles near solid boundaries relative to that of isolated spherical bubbles is also discussed.

  3. Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems

    International Nuclear Information System (INIS)

    Siemer, D.D.

    1989-01-01

    A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to ''seek'' any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these bubbles have a net velocity towards the end of the column where the nominal interface is located, the solids are swept in that direction too. These solids tend to gather in a three-phase ''crud'' layer at the nominal interface point. At equilibrium, about the same amount breaks off from the crud layer and escapes into the liquid exiting from that end of the column as enters it from the other side. If large enough, the crud layer can even interfere with interface detection and control equipment. In packed-column extraction systems, an additional problem is that feed solids can accumulate within the packing material to the point that the column '' floods'' or even totally plugs. The keys to preventing solids-related problems is the correct choice of interface level, and with packed columns, the addition of a ''pulsing leg'' at the bottom of the column. Pulsing packed column systems not only prevents solids from settling onto packing material but it also increses the number of theoretical stages available for extraction. 3 figs., 2 tabs

  4. Bursting Bubbles and Bilayers

    Directory of Open Access Journals (Sweden)

    Steven P. Wrenn, Stephen M. Dicker, Eleanor F. Small, Nily R. Dan, Michał Mleczko, Georg Schmitz, Peter A. Lewin

    2012-01-01

    Full Text Available This paper discusses various interactions between ultrasound, phospholipid monolayer-coated gas bubbles, phospholipid bilayer vesicles, and cells. The paper begins with a review of microbubble physics models, developed to describe microbubble dynamic behavior in the presence of ultrasound, and follows this with a discussion of how such models can be used to predict inertial cavitation profiles. Predicted sensitivities of inertial cavitation to changes in the values of membrane properties, including surface tension, surface dilatational viscosity, and area expansion modulus, indicate that area expansion modulus exerts the greatest relative influence on inertial cavitation. Accordingly, the theoretical dependence of area expansion modulus on chemical composition - in particular, poly (ethylene glyclol (PEG - is reviewed, and predictions of inertial cavitation for different PEG molecular weights and compositions are compared with experiment. Noteworthy is the predicted dependence, or lack thereof, of inertial cavitation on PEG molecular weight and mole fraction. Specifically, inertial cavitation is predicted to be independent of PEG molecular weight and mole fraction in the so-called mushroom regime. In the “brush” regime, however, inertial cavitation is predicted to increase with PEG mole fraction but to decrease (to the inverse 3/5 power with PEG molecular weight. While excellent agreement between experiment and theory can be achieved, it is shown that the calculated inertial cavitation profiles depend strongly on the criterion used to predict inertial cavitation. This is followed by a discussion of nesting microbubbles inside the aqueous core of microcapsules and how this significantly increases the inertial cavitation threshold. Nesting thus offers a means for avoiding unwanted inertial cavitation and cell death during imaging and other applications such as sonoporation. A review of putative sonoporation mechanisms is then presented

  5. Bubble Dynamics in Laser Lithotripsy

    International Nuclear Information System (INIS)

    Mohammadzadeh, Milad; Mercado, Julian Martinez; Ohl, Claus-Dieter

    2015-01-01

    Laser lithotripsy is a medical procedure for fragmentation of urinary stones with a fiber guided laser pulse of several hundred microseconds long. Using high-speed photography, we present an in-vitro study of bubble dynamics and stone motion induced by Ho:YAG laser lithotripsy. The experiments reveal that detectable stone motion starts only after the bubble collapse, which we relate with the collapse-induced liquid flow. Additionally, we model the bubble formation and dynamics using a set of 2D Rayleigh-Plesset equations with the measured laser pulse profile as an input. The aim is to reduce stone motion through modification of the temporal laser pulse profile, which affects the collapse scenario and consequently the remnant liquid motion. (paper)

  6. Hamiltonian description of bubble dynamics

    International Nuclear Information System (INIS)

    Maksimov, A. O.

    2008-01-01

    The dynamics of a nonspherical bubble in a liquid is described within the Hamiltonian formalism. Primary attention is focused on the introduction of the canonical variables into the computational algorithm. The expansion of the Dirichlet-Neumann operator in powers of the displacement of a bubble wall from an equilibrium position is obtained in the explicit form. The first three terms (more specifically, the second-, third-, and fourth-order terms) in the expansion of the Hamiltonian in powers of the canonical variables are determined. These terms describe the spectrum and interaction of three essentially different modes, i.e., monopole oscillations (pulsations), dipole oscillations (translational motions), and surface oscillations. The cubic nonlinearity is analyzed for the problem associated with the generation of Faraday ripples on the wall of a bubble in an acoustic field. The possibility of decay processes occurring in the course of interaction of surface oscillations for the first fifteen (experimentally observed) modes is investigated.

  7. How Stressful Is "Deep Bubbling"?

    Science.gov (United States)

    Tyrmi, Jaana; Laukkanen, Anne-Maria

    2017-03-01

    Water resistance therapy by phonating through a tube into the water is used to treat dysphonia. Deep submersion (≥10 cm in water, "deep bubbling") is used for hypofunctional voice disorders. Using it with caution is recommended to avoid vocal overloading. This experimental study aimed to investigate how strenuous "deep bubbling" is. Fourteen subjects, half of them with voice training, repeated the syllable [pa:] in comfortable speaking pitch and loudness, loudly, and in strained voice. Thereafter, they phonated a vowel-like sound both in comfortable loudness and loudly into a glass resonance tube immersed 10 cm into the water. Oral pressure, contact quotient (CQ, calculated from electroglottographic signal), and sound pressure level were studied. The peak oral pressure P(oral) during [p] and shuttering of the outer end of the tube was measured to estimate the subglottic pressure P(sub) and the mean P(oral) during vowel portions to enable calculation of transglottic pressure P(trans). Sensations during phonation were reported with an open-ended interview. P(sub) and P(oral) were higher in "deep bubbling" and P(trans) lower than in loud syllable phonation, but the CQ did not differ significantly. Similar results were obtained for the comparison between loud "deep bubbling" and strained phonation, although P(sub) did not differ significantly. Most of the subjects reported "deep bubbling" to be stressful only for respiratory and lip muscles. No big differences were found between trained and untrained subjects. The CQ values suggest that "deep bubbling" may increase vocal fold loading. Further studies should address impact stress during water resistance exercises. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  8. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    , and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model...

  9. Bubble dynamics equations in Newton fluid

    International Nuclear Information System (INIS)

    Xiao, J

    2008-01-01

    For the high-speed flow of Newton fluid, bubble is produced and expanded when it moves toward the surface of fluid. Bubble dynamics is a very important research field to understand the intrinsic feature of bubble production and motion. This research formulates the bubble expansion by expansion-local rotation transformation, which can be calculated by the measured velocity field. Then, the related dynamic equations are established to describe the interaction between the fluid and the bubble. The research shows that the bubble production condition can be expressed by critical vortex value and fluid pressure; and the bubble expansion rate can be obtained by solving the non-linear dynamic equation of bubble motion. The results may help the related research as it shows a special kind of fluid motion in theoretic sense. As an application example, the nanofiber radium-voltage relation and threshold voltage-surface tension relation in electrospinning process are discussed

  10. Bubble nucleation in an explosive micro-bubble actuator

    NARCIS (Netherlands)

    van den Broek, D.M.; Elwenspoek, Michael Curt

    2008-01-01

    Explosive evaporation occurs when a thin layer of liquid reaches a temperature close to the critical temperature in a very short time. At these temperatures spontaneous nucleation takes place. The nucleated bubbles instantly coalesce forming a vapour film followed by rapid growth due to the pressure

  11. Formation of soap bubbles by gas jet

    OpenAIRE

    Zhou, M. L.; Li, M.; Chen, Z. Y.; Han, J. F.; Liu, D.

    2017-01-01

    Soap bubbles can be easily generated by varies methods, while their formation process is complicated and still worth study. A model about the bubble formation process was proposed in Phys. Rev. Lett. 116, 077801 recently, and it was reported that the bubbles were formed when the gas blowing velocity was above one threshold. However, after repeating these experiments, we found the bubbles could be generated in two velocities ranges which corresponded to laminar and turbulent gas jet respective...

  12. Columns in Clay

    Science.gov (United States)

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  13. Slender CRC Columns

    DEFF Research Database (Denmark)

    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter

    2005-01-01

    CRC is a high-performance steel fibre reinforced concrete with a typical compressive strength of 150 MPa. Design methods for a number of structural elements have been developed since CRC was invented in 1986, but the current project set out to further investigate the range of columns for which...

  14. Practical column design guide

    CERN Document Server

    Nitsche, M

    2017-01-01

    This book highlights the aspects that need to be considered when designing distillation columns in practice. It discusses the influencing parameters as well as the equations governing them, and presents several numerical examples. The book is intended both for experienced designers and for those who are new to the subject.

  15. Dissolution of methane bubbles with hydrate armoring in deep ocean conditions

    Science.gov (United States)

    Kovalchuk, Margarita; Socolofsky, Scott

    2017-11-01

    The deep ocean is a storehouse of natural gas. Methane bubble moving upwards from marine sediments may become trapped in gas hydrates. It is uncertain precisely how hydrate armoring affects dissolution, or mass transfer from the bubble to the surrounding water column. The Texas A&M Oilspill Calculator was used to simulate a series of gas bubble dissolution experiments conducted in the United States Department of Energy National Energy Technology Laboratory High Pressure Water Tunnel. Several variations of the mass transfer coefficient were calculated based on gas or hydrate phase solubility and clean or dirty bubble correlations. Results suggest the mass transfer coefficient may be most closely modeled with gas phase solubility and dirty bubble correlation equations. Further investigation of hydrate bubble dissolution behavior will refine current numeric models which aid in understanding gas flux to the atmosphere and plumes such as oil spills. Research funded in part by the Texas A&M University 2017 Undergraduate Summer Research Grant and a Grant from the Methane Gas Hydrates Program of the US DOE National Energy Technology Laboratory.

  16. Experimental and numerical study of the migration of gas bubbles through an interface between two liquids

    International Nuclear Information System (INIS)

    Bonhomme, R.

    2012-01-01

    In order to predict the evolution of a hypothetical accident in pressurized water nuclear reactors, this study aims to understand the dynamics of gas bubbles ascending in a stratified mixture made of two superimposed liquids. To this aim, an experimental device equipped with two high-speed video cameras was designed, allowing us to observe isolated air bubbles and bubble trains crossing a horizontal interface separating two Newtonian immiscible liquids initially at rest. The size of the bubbles and the viscosity contrast between the two liquids were varied by more than one and four orders of magnitude respectively, making it possible to observe a wide variety of flow regimes. In some situations, small millimetric bubbles remain trapped at the liquid-liquid interface, whereas larger bubbles succeed in crossing the interface and tow a significant column of lower fluid behind them. After the influence of the physical parameters was qualitatively established thanks to simple models, direct numerical simulations of several selected experimental situations were performed with two different approaches. These are both based on the incompressible Navier-Stokes equations, one making use of an interface capturing technique, the other of a diffuse Cahn-Hilliard description. Comparisons between experimental and numerical results confirmed the reliability of the computational approaches in most situations but also highlighted the need for improvements to capture small-scale physical phenomena especially those related to film drainage. (author)

  17. Mechanics of gas-vapor bubbles

    NARCIS (Netherlands)

    Hao, Yue; Zhang, Yuhang; Prosperetti, Andrea

    2017-01-01

    Most bubbles contain a mixture of vapor and incondensible gases. While the limit cases of pure vapor and pure gas bubbles are well studied, much less is known about the more realistic case of a mixture. The bubble contents continuously change due to the combined effects of evaporation and

  18. Vapor Bubbles in Flow and Acoustic Fields

    NARCIS (Netherlands)

    Prosperetti, Andrea; Hao, Yue; Sadhal, S.S

    2002-01-01

    A review of several aspects of the interaction of bubbles with acoustic and flow fields is presented. The focus of the paper is on bubbles in hot liquids, in which the bubble contains mostly vapor, with little or no permanent gas. The topics covered include the effect of translation on condensation

  19. Computing bubble-points of CO

    NARCIS (Netherlands)

    Ramdin, M.; Balaji, S.P.; Vicent Luna, J.M.; Torres-Knoop, A; Chen, Q.; Dubbeldam, D.; Calero, S; de Loos, T.W.; Vlugt, T.J.H.

    2016-01-01

    Computing bubble-points of multicomponent mixtures using Monte Carlo simulations is a non-trivial task. A new method is used to compute gas compositions from a known temperature, bubble-point pressure, and liquid composition. Monte Carlo simulations are used to calculate the bubble-points of

  20. Experimental study of vapor bubble dynamics

    International Nuclear Information System (INIS)

    Pasquini, Maria-Elena

    2015-01-01

    The object of this thesis is an experimental study of vapor bubble dynamics in sub-cooled nucleate boiling. The test section is locally heated by focusing a laser beam: heat fluxes from 1 e4 to 1.5 e6 W/m 2 and water temperature between 100 and 88 C have been considered. Three boiling regimes have been observed. Under saturated conditions and with low heat fluxes a developed nucleate boiling regime has been observed. Under higher sub-cooling and still with low heat fluxes an equilibrium regime has been observed in which the liquid flowrate evaporating at the bubble base is compensated by the vapor condensing flowrate at bubble top. A third regime have been observed at high heat fluxes for all water conditions: it is characterized by the formation of a large dry spot on the heated surface that keeps the nucleation site dry after bubble detachment. The condensation phase starts after bubble detachment. Bubble equivalent radius at detachment varies between 1 and 2.5 mm. Bubble properties have been measured and non-dimensional groups have been used to characterize bubble dynamics. Capillary waves have been observed on the bubble surface thanks to high-speed images acquisition. Two main phenomena have been proposed to explain capillary waves effects on bubble condensation: increasing of the phases interface area and decreasing of vapor bubble translation velocity, because of the increased drag force on the deformed bubble. (author) [fr

  1. Droplets, Bubbles and Ultrasound Interactions

    NARCIS (Netherlands)

    Shpak, O.; Verweij, M.; de Jong, N.; Versluis, Michel; Escoffre, J.M.; Bouakaz, A.

    2016-01-01

    The interaction of droplets and bubbles with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to

  2. "Financial Bubbles" and Monetary Policy

    Science.gov (United States)

    Tikhonov, Yuriy A.; Pudovkina, Olga E.; Permjakova, Juliana V.

    2016-01-01

    The relevance of this research is caused by the need of strengthening a role of monetary regulators to prevent financial bubbles in the financial markets. The aim of the article is the analysis of a problem of crisis phenomena in the markets of financial assets owing to an inadequate growth of their cost, owing to subjective reasons. The leading…

  3. Soliton bubbles and phase transformations

    International Nuclear Information System (INIS)

    Masperi, L.

    1989-01-01

    It is shown that no topological classical solutions in form of bubbles of a real scalar field theory with Lagrangian of quartet and sextet self interactions in 1+1 dimensions are responsible to discontinue transitions in the quantum problem between phases with degenerated and disordered excited level. (M.C.K.)

  4. Impurity bubbles in a BEC

    Science.gov (United States)

    Timmermans, Eddy; Blinova, Alina; Boshier, Malcolm

    2013-05-01

    Polarons (particles that interact with the self-consistent deformation of the host medium that contains them) self-localize when strongly coupled. Dilute Bose-Einstein condensates (BECs) doped with neutral distinguishable atoms (impurities) and armed with a Feshbach-tuned impurity-boson interaction provide a unique laboratory to study self-localized polarons. In nature, self-localized polarons come in two flavors that exhibit qualitatively different behavior: In lattice systems, the deformation is slight and the particle is accompanied by a cloud of collective excitations as in the case of the Landau-Pekar polarons of electrons in a dielectric lattice. In natural fluids and gases, the strongly coupled particle radically alters the medium, e.g. by expelling the host medium as in the case of the electron bubbles in superfluid helium. We show that BEC-impurities can self-localize in a bubble, as well as in a Landau-Pekar polaron state. The BEC-impurity system is fully characterized by only two dimensionless coupling constants. In the corresponding phase diagram the bubble and Landau-Pekar polaron limits correspond to large islands separated by a cross-over region. The same BEC-impurity species can be adiabatically Feshbach steered from the Landau-Pekar to the bubble regime. This work was funded by the Los Alamos LDRD program.

  5. Explosive micro-bubble actuator

    NARCIS (Netherlands)

    van den Broek, D.M.; Elwenspoek, Michael Curt

    2007-01-01

    Explosive evaporation occurs when a thin layer of liquid reaches a very high temperature in a very short time. At these temperatures homogeneous nucleation takes place. The nucleated bubbles almost instantly coalesce forming a vapour film followed by rapid growth due to the pressure impulse and

  6. Bubbles generated from wind-steepened breaking waves: 2. Bubble plumes, bubbles, and wave characteristics

    NARCIS (Netherlands)

    Leifer, I.; Caulliez, G.; Leeuw, G.de

    2006-01-01

    Measurements of breaking-wave-generated bubble plumes were made in fresh (but not clean) water in a large wind-wave tunnel. To preserve diversity, a classification scheme was developed on the basis of plume dimensions and "optical density," or the plume's ability to obscure the background. Optically

  7. An equation of motion for bubble growth

    Energy Technology Data Exchange (ETDEWEB)

    Lesage, F.J. [College d' Enseignement General et Professionnel de L' Outaouais, Gatineau, Quebec (Canada). Dept. of Mathematics; Cotton, J.S. [McMaster University, Hamilton, ON (Canada). Dept. of Mechanical Engineering; Robinson, A.J. [Trinity College Dublin (Ireland). Dept. of Mechanical and Manufacturing Engineering

    2009-07-01

    A mathematical model is developed which describes asymmetric bubble growth, either during boiling or bubble injection from submerged orifices. The model is developed using the integral form of the continuity and momentum equations, resulting in a general expression for the acceleration of the bubble's centre of gravity. The proposed model highlights the need to include acceleration due to an asymmetric gain or loss of mass in order to accurately predict bubble motion. Some scenarios are posed by which the growth of bubbles, particularly idealized bubbles that remain a section of a sphere, must include the fact that bubble growth can be asymmetric. In particular, for approximately hemispherical bubble growth the sum of the forces acting on the bubble is negligible compared with the asymmetric term. Further, for bubble injection from a submerged needle this component in the equation of motion is very significant during the initial rapid growth phase as the bubble issues from the nozzle changing from a near hemisphere to truncated sphere geometry. (author)

  8. An equation of motion for bubble growth

    International Nuclear Information System (INIS)

    Lesage, F.J.; Cotton, J.S.; Robinson, A.J.

    2009-01-01

    A mathematical model is developed which describes asymmetric bubble growth, either during boiling or bubble injection from submerged orifices. The model is developed using the integral form of the continuity and momentum equations, resulting in a general expression for the acceleration of the bubble's centre of gravity. The proposed model highlights the need to include acceleration due to an asymmetric gain or loss of mass in order to accurately predict bubble motion. Some scenarios are posed by which the growth of bubbles, particularly idealized bubbles that remain a section of a sphere, must include the fact that bubble growth can be asymmetric. In particular, for approximately hemispherical bubble growth the sum of the forces acting on the bubble is negligible compared with the asymmetric term. Further, for bubble injection from a submerged needle this component in the equation of motion is very significant during the initial rapid growth phase as the bubble issues from the nozzle changing from a near hemisphere to truncated sphere geometry. (author)

  9. Bidirectional cinematography of steam-bubble growth

    International Nuclear Information System (INIS)

    Deason, V.A.; Reynolds, L.D.

    1982-01-01

    Single steam bubbles were generated in superheated water in an optical cell. The growth process of the bubbles was recorded with a high-speed motion picture camera at 5000 and 10,000 frames per second. A technique was developed to simultaneously image two orthogonal views of the bubbles on each frame of film. The vertical and horizontal diameters of the bubbles were measured on a frame-by-frame basis, and the data analyzed to determine oscillatory frequencies. The analysis also attempted to determine whether the bubbles were undergoing volumetric oscillations during early growth or whether simple surface wave/rotational behavior caused the observed periodic variations in bubble dimensions. For the bubbles studied, typical oscillation frequencies for the diameters were in the range of 100 to 500 Hz

  10. Bidirectional cinematography of steam-bubble growth

    Energy Technology Data Exchange (ETDEWEB)

    Deason, V.A.; Reynolds, L.D.

    1982-01-01

    Single steam bubbles were generated in superheated water in an optical cell. The growth process of the bubbles was recorded with a high-speed motion picture camera at 5000 and 10,000 frames per second. A technique was developed to simultaneously image two orthogonal views of the bubbles on each frame of film. The vertical and horizontal diameters of the bubbles were measured on a frame-by-frame basis, and the data analyzed to determine oscillatory frequencies. The analysis also attempted to determine whether the bubbles were undergoing volumetric oscillations during early growth or whether simple surface wave/rotational behavior caused the observed periodic variations in bubble dimensions. For the bubbles studied, typical oscillation frequencies for the diameters were in the range of 100 to 500 Hz.

  11. Nine Words - Nine Columns

    DEFF Research Database (Denmark)

    Trempe Jr., Robert B.; Buthke, Jan

    2016-01-01

    This book records the efforts of a one-week joint workshop between Master students from Studio 2B of Arkitektskolen Aarhus and Master students from the Harbin Institute of Technology in Harbin, China. The workshop employed nine action words to instigate team-based investigation into the effects o...... as formwork for the shaping of wood veneer. The resulting columns ‘wear’ every aspect of this design pipeline process and display the power of process towards an architectural resolution....

  12. Hydrogen extraction from liquid lithium-lead alloy by bubbling with rotational jet nozzle

    International Nuclear Information System (INIS)

    Xie Bo; Yang Tongzai; Guan Rui; Weng Kuiping

    2010-01-01

    The technology of tritium extraction from lithium-lead alloy has been simulated, hydrogen extraction from lithium-lead alloy by bubbling with rotational jet nozzle being used to simulate tritium in the study based on the introduction of fluid dynamics to establish algebraic model. The results show that the higher than lithium-lead melting temperature, the higher cumulative hydrogen extraction efficiency, and gas holdup of bubble column is little affected by the impeller diameter. Gas holdup when using small aperture is slightly higher when using large aperture only at a high helium flow rate, but the smaller the aperture, the greater the bubble surface area, and a marked increase in intensity of flow circulation for liquid lithium-lead with the increase of helium flow rate, hydrogen extraction rate increases too. Moreover, influence of the jet rotational velocity on hydrogen extraction is limited. (authors)

  13. NMFS Water Column Sonar Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water column sonar data are an important component of fishery independent surveys, habitat studies and other research. NMFS water column sonar data are archived here.

  14. Safety operation of chromatography column system with discharging hydrogen radiolytically generated

    International Nuclear Information System (INIS)

    Watanabe, S; Sano, Y.; Nomura, K.; Koma, Y.; Okamoto, Y.

    2015-01-01

    The extraction chromatography technology is one of the promising methods for the partitioning of minor actinides (Am and Cm) from spent nuclear fuels. In the extraction chromatography system, the accumulation of hydrogen gas in the chromatography column is suspected to lead to fire or explosion. In order to prevent hazardous accidents, it is necessary to evaluate behaviors of gas radiolytically generated inside the column. In this study, behaviors of gas inside the extraction chromatography column were investigated through experiments and Computation Fluid Dynamics (CFD) simulation. N_2 gas once accumulated as bubbles in the packed bed was hardly discharged by the flow of mobile phase. However, the CFD simulation and X-ray imaging on γ-ray irradiated column revealed that during operation the hydrogen gas generated in the column was dissolved into the mobile phase without accumulation and then discharged. (authors)

  15. Bubble entrapment through topological change

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2010-05-03

    When a viscousdrop impacts onto a solid surface, it entraps a myriad of microbubbles at the interface between liquid and solid. We present direct high-speed video observations of this entrapment. For viscousdrops, the tip of the spreading lamella is separated from the surface and levitated on a cushion of air. We show that the primary mechanism for the bubble entrapment is contact between this precursor sheet of liquid with the solid and not air pulled directly through cusps in the contact line. The sheet makes contact with the solid surface,forming a wetted patch, which grows in size, but only entraps a bubble when it meets the advancing contact line. The leading front of this wet patch can also lead to the localized thinning and puncturing of the liquid film producing strong splashing of droplets.

  16. Bubbling in vibrated granular films.

    Science.gov (United States)

    Zamankhan, Piroz

    2011-02-01

    With the help of experiments, computer simulations, and a theoretical investigation, a general model is developed of the flow dynamics of dense granular media immersed in air in an intermediate regime where both collisional and frictional interactions may affect the flow behavior. The model is tested using the example of a system in which bubbles and solid structures are produced in granular films shaken vertically. Both experiments and large-scale, three-dimensional simulations of this system are performed. The experimental results are compared with the results of the simulation to verify the validity of the model. The data indicate evidence of formation of bubbles when peak acceleration relative to gravity exceeds a critical value Γ(b). The air-grain interfaces of bubblelike structures are found to exhibit fractal structure with dimension D=1.7±0.05.

  17. Bubble entrapment through topological change

    KAUST Repository

    Thoroddsen, Sigurdur T; Takehara, K.; Etoh, T. G.

    2010-01-01

    When a viscousdrop impacts onto a solid surface, it entraps a myriad of microbubbles at the interface between liquid and solid. We present direct high-speed video observations of this entrapment. For viscousdrops, the tip of the spreading lamella is separated from the surface and levitated on a cushion of air. We show that the primary mechanism for the bubble entrapment is contact between this precursor sheet of liquid with the solid and not air pulled directly through cusps in the contact line. The sheet makes contact with the solid surface,forming a wetted patch, which grows in size, but only entraps a bubble when it meets the advancing contact line. The leading front of this wet patch can also lead to the localized thinning and puncturing of the liquid film producing strong splashing of droplets.

  18. Bubble collisions in general relativity

    International Nuclear Information System (INIS)

    Siklos, S.T.C.; Wu, Z.C.; University of Science and Technology of China, Hofei, Anhwei)

    1983-01-01

    The collision of two bubbles of true vacuum in a background of false vacuum is considered in the context of General Relativity. It is found that in the thin wall approximation, the problem, can be solved exactly. The region to the future of the collision is described by the pseudo-Schwarzschild de Sitter metric. The parameters in this metric are found by solving the junction conditions at each collision. (author)

  19. BEBC Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    A view of the dismantling of the magnet of BEBC, the 3.7 m European Bubble Chamber : iron magnetic shielding ; lower and upper parts of the vacuum enclosure of the magnet; turbo-molecular vacuum pumps for the "fish-eye" windows; the two superconducting coils; a handling platform; the two cryostats suspended from the bar of the travelling crane which has a 170 ton carrying capacity. The chamber proper, not dismantled, is inside the shielding.

  20. Bubbling Controlled by Needle Movement

    Czech Academy of Sciences Publication Activity Database

    Vejražka, Jiří; Zedníková, Mária; Stanovský, Petr; Růžička, Marek; Drahoš, Jiří

    2008-01-01

    Roč. 40, 7-8 (2008), s. 521-533 ISSN 0169-5983 R&D Projects: GA ČR GP101/05/P229; GA ČR(CZ) GA104/05/2566 Institutional research plan: CEZ:AV0Z40720504 Keywords : bubble * detechment * control Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.012, year: 2008

  1. Informational pathologies and interest bubbles

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Wiewiura, Joachim Schmidt

    2017-01-01

    This article contends that certain configurations of information networks facilitate specific cognitive states that are instrumental for decision and action on social media. Group-related knowledge and belief states—in particular common knowledge and pluralistic ignorance—may enable strong public...... signals. Indeed, some network configurations and attitude states foster informational pathologies that may fuel interest bubbles affecting agenda-setting and the generation of narratives in public spheres....

  2. When Will Occur the Crude Oil Bubbles?

    International Nuclear Information System (INIS)

    Su, Chi-Wei; Li, Zheng-Zheng; Chang, Hsu-Ling; Lobonţ, Oana-Ramona

    2017-01-01

    In this paper, we apply a recursive unit root test to investigate whether there exist multiple bubbles in crude oil price. The method is best suited for a practical implementation of a time series and delivers a consistent date-stamping strategy for the origination and termination of multiple bubbles. The empirical result indicates that there exist six bubbles during 1986–2016 when the oil price deviate from its intrinsic value based on market fundamentals. Specifically, oil price contains the fundamentals and bubble components. The dates of the bubbles correspond to specific events in the politics and financial markets. The authorities should actively fight speculative bubbles or just observe their evolutions and speculation activities may decrease, which is favour of the stabilisation of the staple commodities including crude oil price. These findings have important economic and policy implications to recognise the cause of bubbles and take corresponding measures to reduce the impact on the real economy cause of the fluctuation of crude oil price. - Highlights: • Investigate multiple bubbles in crude oil price. • Indicate six bubbles deviate from its intrinsic value based on market fundamentals. • The bubbles correspond to specific events in the politics and financial markets. • Reduce the impact on the real economy cause of the fluctuation of crude oil price.

  3. Armoring confined bubbles in concentrated colloidal suspensions

    Science.gov (United States)

    Yu, Yingxian; Khodaparast, Sepideh; Stone, Howard

    2016-11-01

    Encapsulation of a bubble with microparticles is known to significantly improve the stability of the bubble. This phenomenon has recently gained increasing attention due to its application in a variety of technologies such as foam stabilization, drug encapsulation and colloidosomes. Nevertheless, the production of such colloidal armored bubble with controlled size and particle coverage ratio is still a great challenge industrially. We study the coating process of a long air bubble by microparticles in a circular tube filled with a concentrated microparticles colloidal suspension. As the bubble proceeds in the suspension of particles, a monolayer of micro-particles forms on the interface of the bubble, which eventually results in a fully armored bubble. We investigate the phenomenon that triggers and controls the evolution of the particle accumulation on the bubble interface. Moreover, we examine the effects of the mean flow velocity, the size of the colloids and concentration of the suspension on the dynamics of the armored bubble. The results of this study can potentially be applied to production of particle-encapsulated bubbles, surface-cleaning techniques, and gas-assisted injection molding.

  4. Simulation of bubbly flow in vertical pipes by coupling Lagrangian and Eulerian models with 3D random walks models: validation with experimental data using multi-sensor conductivity probes and laser doppler anemometry

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Cobo, J.L. [Univ. Politecnica de Valencia, Inst. de Ingenieria Energetica, Valencia (Spain); Chiva, S. [Univ. Jaume I, Dept. of Mechnical Engineering and Construction, Castellon (Spain); Abd El Aziz Essa, M. [Univ. Politecnica de Valencia, Inst. de Ingenieria Energetica, Valencia (Spain); Mendes, S. [Univ. Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica (Mexico)

    2011-07-01

    A set of air-water experiments have been performed under isothermal upward concurrent flow in a vertical column. The interfacial velocity, interfacial area of the bubbles and the void fraction distributions was obtained. Numerical validation of these results for bubbly flow conditions were performed by coupling a Lagrangian code which tracks the 3D motion of the individual bubbles, with an Eulerian one. Both Lagrangian and Eulerian calculations were performed in parallel and iterative self-consistent method was developed. The bubbles-induced turbulence is an important issue considered, to obtain good predictions of experimental results. (author)

  5. Elevator frames two columns

    OpenAIRE

    Marín Jiménez, Juan Francisco

    2015-01-01

    This project aims to solve the problem of vertical transport of charges raised by a company with the standard UNE 58-132-91/6. The purpose of this project is the industrial design of a system of load handling by a bi-columned lifting device, tractioned by flat belts and steel cables from a transport level to a different level in order to connect two different assembly lines situated at different heights. The goal of this project is lifting a 780 Kg load at a 2.400 mm height....

  6. Column: Every Last Byte

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-06-01

    Full Text Available Inheritance powder is the name that was given to poisons, especially arsenic, that were commonly used in the 17th and early 18th centuries to hasten the death of the elderly. For most of the 17th century, arsenic was deadly but undetectable, making it nearly impossible to prove that someone had been poisoned. The first arsenic test produced a gas—hardly something that a scientist could show to a judge. Faced with a growing epidemic of poisonings, doctors and chemists spent decades searching for something better.(see PDF for full column

  7. Numerical simulation of bubbles motion in lifting pipe of bubble pump for lithium bromide absorption chillers

    International Nuclear Information System (INIS)

    Gao, Hongtao; Liu, Bingbing; Yan, Yuying

    2017-01-01

    A bubble pump is proposed to replace the traditional mechanical solution pump in lithium bromide absorption chillers, for its advantageous feature that can be driven by industrial waste heat or solar energy or other low-grade energy. In two-stage bubble pump driven lithium bromide absorption refrigeration system, flow patterns in lifting pipe have significant effects on the performance of bubble pump. In this paper, the single bubble motion and the double bubbles coalescence in vertical ascending pipe are simulated by an improved free energy model of lattice Boltzmann method, in which the two-phase liquid to gas density ratio is 2778. The details of bubbles coalescence process are studied. Density and velocity of bubbles have been obtained. The computational results show that the initial radius of each bubble has a great influence on the coalescence time. The larger the initial bubble radius, the shorter the coalescence time. The pipe diameter has a little effect on the two bubbles coalescence time while it has a significant effect on the bubble velocity. As the pipe diameter increases, the bubble velocity increases. The obtained results are helpful for studying the transition mechanisms of two-phase flow patterns and useful for improving the bubble pump performance by controlling the flow patterns in lifting pipe.

  8. Annular pulse column development studies

    International Nuclear Information System (INIS)

    Benedict, G.E.

    1980-01-01

    The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein. The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases. The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other

  9. Single DNA denaturation and bubble dynamics

    International Nuclear Information System (INIS)

    Metzler, Ralf; Ambjoernsson, Tobias; Hanke, Andreas; Fogedby, Hans C

    2009-01-01

    While the Watson-Crick double-strand is the thermodynamically stable state of DNA in a wide range of temperature and salt conditions, even at physiological conditions local denaturation bubbles may open up spontaneously due to thermal activation. By raising the ambient temperature, titration, or by external forces in single molecule setups bubbles proliferate until full denaturation of the DNA occurs. Based on the Poland-Scheraga model we investigate both the equilibrium transition of DNA denaturation and the dynamics of the denaturation bubbles with respect to recent single DNA chain experiments for situations below, at, and above the denaturation transition. We also propose a new single molecule setup based on DNA constructs with two bubble zones to measure the bubble coalescence and extract the physical parameters relevant to DNA breathing. Finally we consider the interplay between denaturation bubbles and selectively single-stranded DNA binding proteins.

  10. Bernoulli Suction Effect on Soap Bubble Blowing?

    Science.gov (United States)

    Davidson, John; Ryu, Sangjin

    2015-11-01

    As a model system for thin-film bubble with two gas-liquid interfaces, we experimentally investigated the pinch-off of soap bubble blowing. Using the lab-built bubble blower and high-speed videography, we have found that the scaling law exponent of soap bubble pinch-off is 2/3, which is similar to that of soap film bridge. Because air flowed through the decreasing neck of soap film tube, we studied possible Bernoulli suction effect on soap bubble pinch-off by evaluating the Reynolds number of airflow. Image processing was utilized to calculate approximate volume of growing soap film tube and the volume flow rate of the airflow, and the Reynolds number was estimated to be 800-3200. This result suggests that soap bubbling may involve the Bernoulli suction effect.

  11. Formation of soap bubbles by gas jet

    Science.gov (United States)

    Zhou, Maolei; Li, Min; Chen, Zhiyuan; Han, Jifeng; Liu, Dong

    2017-12-01

    Soap bubbles can be easily generated by various methods, while their formation process is complicated and still worth studying. A model about the bubble formation process was proposed in the study by Salkin et al. [Phys. Rev. Lett. 116, 077801 (2016)] recently, and it was reported that the bubbles were formed when the gas blowing velocity was above one threshold. However, after a detailed study of these experiments, we found that the bubbles could be generated in two velocity ranges which corresponded to the laminar and turbulent gas jet, respectively, and the predicted threshold was only effective for turbulent gas flow. The study revealed that the bubble formation was greatly influenced by the aerodynamics of the gas jet blowing to the film, and these results will help to further understand the formation mechanism of the soap bubble as well as the interaction between the gas jet and the thin liquid film.

  12. Manipulating bubbles with secondary Bjerknes forces

    Energy Technology Data Exchange (ETDEWEB)

    Lanoy, Maxime [Institut Langevin, ESPCI ParisTech, CNRS (UMR 7587), PSL Research University, 1 rue Jussieu, 75005 Paris (France); Laboratoire Matière et Systèmes Complexes, Université Paris-Diderot, CNRS (UMR 7057), 10 rue Alice Domon et Léonie Duquet, 75013 Paris (France); Derec, Caroline; Leroy, Valentin [Laboratoire Matière et Systèmes Complexes, Université Paris-Diderot, CNRS (UMR 7057), 10 rue Alice Domon et Léonie Duquet, 75013 Paris (France); Tourin, Arnaud [Institut Langevin, ESPCI ParisTech, CNRS (UMR 7587), PSL Research University, 1 rue Jussieu, 75005 Paris (France)

    2015-11-23

    Gas bubbles in a sound field are submitted to a radiative force, known as the secondary Bjerknes force. We propose an original experimental setup that allows us to investigate in detail this force between two bubbles, as a function of the sonication frequency, as well as the bubbles radii and distance. We report the observation of both attractive and, more interestingly, repulsive Bjerknes force, when the two bubbles are driven in antiphase. Our experiments show the importance of taking multiple scatterings into account, which leads to a strong acoustic coupling of the bubbles when their radii are similar. Our setup demonstrates the accuracy of secondary Bjerknes forces for attracting or repealing a bubble, and could lead to new acoustic tools for noncontact manipulation in microfluidic devices.

  13. Mechanism of bubble detachment from vibrating walls

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongjun; Park, Jun Kwon, E-mail: junkeun@postech.ac.kr; Kang, Kwan Hyoung [Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Kang, In Seok [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of)

    2013-11-15

    We discovered a previously unobserved mechanism by which air bubbles detach from vibrating walls in glasses containing water. Chaotic oscillation and subsequent water jets appeared when a wall vibrated at greater than a critical level. Wave forms were developed at water-air interface of the bubble by the wall vibration, and water jets were formed when sufficiently grown wave-curvatures were collapsing. Droplets were pinched off from the tip of jets and fell to the surface of the glass. When the solid-air interface at the bubble-wall attachment point was completely covered with water, the bubble detached from the wall. The water jets were mainly generated by subharmonic waves and were generated most vigorously when the wall vibrated at the volume resonant frequency of the bubble. Bubbles of specific size can be removed by adjusting the frequency of the wall's vibration.

  14. The KEK 1 m hydrogen bubble chamber

    International Nuclear Information System (INIS)

    Doi, Yoshikuni; Araoka, Osamu; Hayashi, Kohei; Hayashi, Yoshio; Hirabayashi, Hiromi.

    1978-03-01

    A medium size hydrogen bubble chamber has been constructed at the National Laboratory for High Energy Physics, KEK. The bubble chamber has been designed to be operated with a maximum rate of three times per half a second in every two second repetition time of the accelerator, by utilizing a hydraulic expansion system. The bubble chamber has a one meter diameter and a visible volume of about 280 l. A three-view stereo camera system is used for taking photographic pictures of the chamber. A 2 MW bubble chamber magnet is constructed. The main part of the bubble chamber vessel is supported by the magnet yoke. The magnet gives a maximum field of 18.4 kG at the centre of the fiducial volume of the chamber. The overall system of the KEK 1 m hydrogen bubble chamber facility is described in some detail. Some operational characteristics of the facility are also reported. (auth.)

  15. Manipulating bubbles with secondary Bjerknes forces

    International Nuclear Information System (INIS)

    Lanoy, Maxime; Derec, Caroline; Leroy, Valentin; Tourin, Arnaud

    2015-01-01

    Gas bubbles in a sound field are submitted to a radiative force, known as the secondary Bjerknes force. We propose an original experimental setup that allows us to investigate in detail this force between two bubbles, as a function of the sonication frequency, as well as the bubbles radii and distance. We report the observation of both attractive and, more interestingly, repulsive Bjerknes force, when the two bubbles are driven in antiphase. Our experiments show the importance of taking multiple scatterings into account, which leads to a strong acoustic coupling of the bubbles when their radii are similar. Our setup demonstrates the accuracy of secondary Bjerknes forces for attracting or repealing a bubble, and could lead to new acoustic tools for noncontact manipulation in microfluidic devices

  16. Study of stream flow effects on bubble motion

    International Nuclear Information System (INIS)

    Sami, S.S.

    1983-01-01

    The formation of air bubbles at constant-pressure by submerged orifices was investigated in both quiescent and moving streams inside a vertical tube. Parameters affecting the bubble rise velocity, such as bubble generating frequency and diameter, were studied and analyzed for bubbles rising in a chain and homogeneous mixture. A special technique for measuring bubble motion parameters has been developed, tested, and employed throughout the experimental investigation. The method is based on a water-air impedance variation. Results obtained in stagnant liquid show that increasing the bubble diameter serves to increase bubble rise velocity, while an opposite trend has been observed for stream liquid where the bubble diameter increase reduces the bubble rise velocity. The increase of bubble generation frequency generally increases the bubble rise velocity. Experimental data covered with bubble radial distribution showed symmetrical profiles of bubble velocity and frequency, and the radial distribution of the velocity profiles sometimes has two maxima and one minimum depending on the liquid velocity. Finally, in stagnant liquid, a normalized correlation has been developed to predict the terminal rise velocity in terms of bubble generating frequency, bubble diameter, single bubble rise velocity, and conduit dimensions. Another correlation is presented for forced bubbly flow, where the bubble rise velocity is expressed as a function of bubble generating frequency, bubble diameter, and water superficial velocity

  17. Water column imaging on hydrothermal vent in Central Indian Ridge

    Science.gov (United States)

    Koh, J.; Park, Y.

    2017-12-01

    Water column imaging with Multibeam echosounder systems (MBES) is recently becoming of increasing interest for oceanographic studies. Especially gas bubbles and hot water exposed from hydrothermal vents make acoustic impedance anomalies in cold seawater, water column imaging is very useful for the researchers who want to detect some kinds of hydrothermal activity. We conducted a hydrothermal exploration program, called "INVENT17", using the MBES system, KONGBERG EM122 (12kHz, 1°×1°), mounted on R/V ISABU and we deployed other equipments including video guided hydraulic grab, tow-yo CTD and general CTD with MAPR (Miniature Autonomous Plume Recorder) in 2017. First, to evaluate its capabilities of detection of hydrothermal vent, the surveys using the MBES were conducted at the Solitaire Field, previously identified hydrothermal area of the Central Indian Ridge. The bathymetric data obtained from MBES provided information about detailed morphology of seafloor, but we were not able to achieve the information from the water column imaging data. But the clue of existence of active hydrothermal vent was detected through the values of ΔNTU, dEh/dt, and OPR gained from MAPR, the data means that the hydrothermal activity affects 100m from the seafloor. It could be the reason that we can't find the hydrothermal activity because the range resolution of water column imaging is pretty rough so that the size of 100m-scaled activity has low possibility to distinguish from seafloor. The other reason is there are no sufficient objects to cause strong scattering like as CO2 bubbles or droplets unlike in the mid-Okinawa Trough. And this suggests that can be a important standard to identify properties of hydrothermal vent sites depending on the presence of scattering objects in water mass. To justify this, we should perform more chemical analysis of hot water emanating from hydrothermal vent and collected several bottles of water sample to do that.

  18. Local measurements in turbulent bubbly flows

    International Nuclear Information System (INIS)

    Suzanne, C.; Ellingsen, K.; Risso, F.; Roig, V.

    1998-01-01

    Local measurements methods in bubbly flows are discussed. Concerning liquid velocity measurement, problems linked to HFA and LDA are first analysed. Then simultaneously recorded velocity signals obtained by both anemometers are compared. New signal processing are developed for the two techniques. Bubble sizes and velocities measurements methods using intrusive double optical sensor probe are presented. Plane bubbly mixing layer has been investigated. Local measurements using the described methods are presented as examples. (author)

  19. Bursting the bubble of melt inclusions

    Science.gov (United States)

    Lowenstern, Jacob B.

    2015-01-01

    Most silicate melt inclusions (MI) contain bubbles, whose significance has been alternately calculated, pondered, and ignored, but rarely if ever directly explored. Moore et al. (2015) analyze the bubbles, as well as their host glasses, and conclude that they often hold the preponderance of CO2 in the MI. Their findings entreat future researchers to account for the presence of bubbles in MI when calculating volatile budgets, saturation pressures, and eruptive flux.

  20. On Bubble Rising in Countercurrent Flow

    Czech Academy of Sciences Publication Activity Database

    Večeř, M.; Leštinský, P.; Wichterle, K.; Růžička, Marek

    2012-01-01

    Roč. 10, č. 2012 (2012), A30 ISSN 1542-6580 R&D Projects: GA ČR GA104/09/0972; GA ČR GA104/07/1110 Grant - others:GA MŠMT(CZ) CZ.1.05/2.1.00/03.0069 Institutional support: RVO:67985858 Keywords : ellipsoidal bubble * bubble shape * bubble velocity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.790, year: 2011

  1. Fast Initialization of Bubble-Memory Systems

    Science.gov (United States)

    Looney, K. T.; Nichols, C. D.; Hayes, P. J.

    1986-01-01

    Improved scheme several orders of magnitude faster than normal initialization scheme. State-of-the-art commercial bubble-memory device used. Hardware interface designed connects controlling microprocessor to bubblememory circuitry. System software written to exercise various functions of bubble-memory system in comparison made between normal and fast techniques. Future implementations of approach utilize E2PROM (electrically-erasable programable read-only memory) to provide greater system flexibility. Fastinitialization technique applicable to all bubble-memory devices.

  2. Study of CO2 bubble dynamics in seawater from QICS field Experiment

    Science.gov (United States)

    Chen, B.; Dewar, M.; Sellami, N.; Stahl, H.; Blackford, J.

    2013-12-01

    One of the concerns of employing CCS at engineering scale is the risk of leakage of storage CO2 on the environment and especially on the marine life. QICS, a scientific research project was launched with an aim to study the effects of a potential leak from a CCS system on the UK marine environment [1]. The project involves the injection of CO2 from a shore-based lab into shallow marine sediments. One of the main objectives of the project is to generate experimental data to be compared with the developed physical models. The results of the models are vital for the biogeochemical and ecological models in order to predict the impact of a CO2 leak in a variety of situations. For the evaluation of the fate of the CO2 bubbles into the surrounding seawater, the physical model requires two key parameters to be used as input which are: (i) a correlation of the drag coefficient as function of the CO2 bubble Reynolds number and (ii) the CO2 bubble size distribution. By precisely measuring the CO2 bubble size and rising speed, these two parameters can be established. For this purpose, the dynamical characteristics of the rising CO2 bubbles in Scottish seawater were investigated experimentally within the QICS project. Observations of the CO2 bubbles plume rising freely in the in seawater column were captured by video survey using a ruler positioned at the leakage pockmark as dimension reference. This observation made it possible, for the first time, to discuss the dynamics of the CO2 bubbles released in seawater. [1] QICS, QICS: Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage. (Accessed 15.07.13), http://www.bgs.ac.uk/qics/home.html

  3. Bubble nuclei in relativistic mean field theory

    International Nuclear Information System (INIS)

    Shukla, A.; Aberg, S.; Patra, S.K.

    2011-01-01

    Bubble nuclei are characterized by a depletion of their central density, i.e. the formation of the proton or neutron void and subsequently forming proton or neutron bubble nuclei. Possibility of the formation of bubble nuclei has been explored through different nuclear models and in different mass regions. Advancements in experimental nuclear physics has led our experimental access to many new shapes and structures, which were inaccessible hitherto. In the present paper, the possibility of observing nuclear bubble in oxygen isotopes, particularly for 22 O has been studied

  4. Improvised bubble continuous positive airway pressure (BCPAP ...

    African Journals Online (AJOL)

    Improvised bubble continuous positive airway pressure (BCPAP) device at the National Hospital Abuja gives immediate improvement in respiratory rate and oxygenation in neonates with respiratory distress.

  5. The Behavior of Micro Bubbles and Bubble Cluster in Ultrasound Field

    Science.gov (United States)

    Yoshizawa, Shin; Matsumoto, Yoichiro

    2001-11-01

    Ultrasound is widely applied in the clinical field today, such as ultrasound imaging, Extracorporeal Shock Wave Lithotripsy (ESWL) and so on. It is essential to take a real understanding of the dynamics of micro bubbles and bubble cluster in these applications. Thus we numerically simulate them in ultrasound field in this paper. In the numerical simulation, we consider the thermal behavior inside the bubble and the pressure wave phenomena in the bubble cluster in detail, namely, the evaporation and condensation of liquid at the bubble wall, heat transfer through the bubble wall, diffusion of non-condensable gas inside the bubble and the compressibility of liquid. Initial cluster radius is to 0.5[mm], bubble radius is 1.7[mm], void fraction is 0.1[ambient pressure is 101.3[kPa], temperature is 293[K] and the amplitude of ultrasound is 50[kPa]. We simulate bubble cluster in ultrasound field at various frequencies and we obtain the following conclusions. 1) The maximum pressure inside bubble cluster reaches 5[MPa] and this is much higher than that of a bubble. 2) Bubble cluster behaves like a rigid body acoustically when the frequency of ultrasound is much higher than its natural frequency.

  6. Interaction of a bubble and a bubble cluster in an ultrasonic field

    International Nuclear Information System (INIS)

    Wang Cheng-Hui; Cheng Jian-Chun

    2013-01-01

    Using an appropriate approximation, we have formulated the interacting equation of multi-bubble motion for a system of a single bubble and a spherical bubble cluster. The behavior of the bubbles is observed in coupled and uncoupled states. The oscillation of bubbles inside the cluster is in a coupled state. The numerical simulation demonstrates that the secondary Bjerknes force can be influenced by the number density, initial radius, distance, driving frequency, and amplitude of ultrasound. However, if a bubble approaches a bubble cluster of the same initial radii, coupled oscillation would be induced and a repulsive force is evoked, which may be the reason why the bubble cluster can exist steadily. With the increment of the number density of the bubble cluster, a secondary Bjerknes force acting on the bubbles inside the cluster decreases due to the strong suppression of the coupled bubbles. It is shown that there may be an optimal number density for a bubble cluster which can generate an optimal cavitation effect in liquid for a stable driving ultrasound. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

    Science.gov (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

    2017-12-08

    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  8. Column: File Cabinet Forensics

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-12-01

    Full Text Available Researchers can spend their time reverse engineering, performing reverse analysis, or making substantive contributions to digital forensics science. Although work in all of these areas is important, it is the scientific breakthroughs that are the most critical for addressing the challenges that we face.Reverse Engineering is the traditional bread-and-butter of digital forensics research. Companies like Microsoft and Apple deliver computational artifacts (operating systems, applications and phones to the commercial market. These artifacts are bought and used by billions. Some have evil intent, and (if society is lucky, the computers end up in the hands of law enforcement. Unfortunately the original vendors rarely provide digital forensics tools that make their systems amenable to analysis by law enforcement. Hence the need for reverse engineering.(see PDF for full column

  9. Bubbling in unbounded coflowing liquids.

    Science.gov (United States)

    Gañán-Calvo, Alfonso M; Herrada, Miguel A; Garstecki, Piotr

    2006-03-31

    An investigation of the stability of low density and viscosity fluid jets and spouts in unbounded coflowing liquids is presented. A full parametrical analysis from low to high Weber and Reynolds numbers shows that the presence of any fluid of finite density and viscosity inside the hollow jet elicits a transition from an absolute to a convective instability at a finite value of the Weber number, for any value of the Reynolds number. Below that critical value of the Weber number, the absolute character of the instability leads to local breakup, and consequently to local bubbling. Experimental data support our model.

  10. Compact electron beam focusing column

    Science.gov (United States)

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-12-01

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  11. Method for enhancing selectivity and recovery in the fractional flotation of particles in a flotation column

    Science.gov (United States)

    Klunder, Edgar B [Bethel Park, PA

    2011-08-09

    The method relates to particle separation from a feed stream. The feed stream is injected directly into the froth zone of a vertical flotation column in the presence of a counter-current reflux stream. A froth breaker generates a reflux stream and a concentrate stream, and the reflux stream is injected into the froth zone to mix with the interstitial liquid between bubbles in the froth zone. Counter-current flow between the plurality of bubbles and the interstitial liquid facilitates the attachment of higher hydrophobicity particles to bubble surfaces as lower hydrophobicity particles detach. The height of the feed stream injection and the reflux ratio may be varied in order to optimize the concentrate or tailing stream recoveries desired based on existing operating conditions.

  12. Simple improvements to classical bubble nucleation models.

    Science.gov (United States)

    Tanaka, Kyoko K; Tanaka, Hidekazu; Angélil, Raymond; Diemand, Jürg

    2015-08-01

    We revisit classical nucleation theory (CNT) for the homogeneous bubble nucleation rate and improve the classical formula using a correct prefactor in the nucleation rate. Most of the previous theoretical studies have used the constant prefactor determined by the bubble growth due to the evaporation process from the bubble surface. However, the growth of bubbles is also regulated by the thermal conduction, the viscosity, and the inertia of liquid motion. These effects can decrease the prefactor significantly, especially when the liquid pressure is much smaller than the equilibrium one. The deviation in the nucleation rate between the improved formula and the CNT can be as large as several orders of magnitude. Our improved, accurate prefactor and recent advances in molecular dynamics simulations and laboratory experiments for argon bubble nucleation enable us to precisely constrain the free energy barrier for bubble nucleation. Assuming the correction to the CNT free energy is of the functional form suggested by Tolman, the precise evaluations of the free energy barriers suggest the Tolman length is ≃0.3σ independently of the temperature for argon bubble nucleation, where σ is the unit length of the Lennard-Jones potential. With this Tolman correction and our prefactor one gets accurate bubble nucleation rate predictions in the parameter range probed by current experiments and molecular dynamics simulations.

  13. Bubble Swarm Rise Velocity in Fluidized Beds.

    Czech Academy of Sciences Publication Activity Database

    Punčochář, Miroslav; Růžička, Marek; Šimčík, Miroslav

    2016-01-01

    Roč. 152, OCT 2 (2016), s. 84-94 ISSN 0009-2509 R&D Projects: GA ČR(CZ) GA15-05534S Institutional support: RVO:67985858 Keywords : bubbling fluidized bed * gas-solid * bubble swarm velocity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.895, year: 2016

  14. The use of microholography in bubble chambers

    CERN Document Server

    Royer, H

    1981-01-01

    In-line holography has been used for the first time in a bubble chamber for the account of the CERN (Geneva, CH). The holograms were recorded with the help of a single-mode pulse laser. Bubble tracks of 25 microns in diameter have been reconstructed with a resolution of 2 microns. (12 refs).

  15. Cavitation bubble nucleation induced by shock-bubble interaction in a gelatin gel

    Science.gov (United States)

    Oguri, Ryota; Ando, Keita

    2018-05-01

    An optical visualization technique is developed to study cavitation bubble nucleation that results from interaction between a laser-induced shock and a preexisting gas bubble in a 10 wt. % gelatin gel; images of the nucleated cavitation bubbles are captured and the cavitation inception pressure is determined based on Euler flow simulation. A spherical gas cavity is generated by focusing an infrared laser pulse into a gas-supersaturated gel and the size of the laser-generated bubble in mechanical equilibrium is tuned via mass transfer of the dissolved gas into the bubble. A spherical shock is then generated, through rapid expansion of plasma induced by the laser focusing, in the vicinity of the gas bubble. The shock-bubble interaction is recorded by a CCD camera with flash illumination of a nanosecond green laser pulse. The observation captures cavitation inception in the gel under tension that results from acoustic impedance mismatching at the bubble interface interacting with the shock. We measure the probability of cavitation inception from a series of the repeated experiments, by varying the bubble radius and the standoff distance. The threshold pressure is defined at the cavitation inception probability equal to one half and is calculated, through comparisons to Euler flow simulation, at -24.4 MPa. This threshold value is similar to that from shock-bubble interaction experiments using water, meaning that viscoelasticity of the 10 wt. % gelatin gel has a limited impact on bubble nucleation dynamics.

  16. Nonlinear Bubble Dynamics And The Effects On Propagation Through Near-Surface Bubble Layers

    Science.gov (United States)

    Leighton, Timothy G.

    2004-11-01

    Nonlinear bubble dynamics are often viewed as the unfortunate consequence of having to use high acoustic pressure amplitudes when the void fraction in the near-surface oceanic bubble layer is great enough to cause severe attenuation (e.g. >50 dB/m). This is seen as unfortunate since existing models for acoustic propagation in bubbly liquids are based on linear bubble dynamics. However, the development of nonlinear models does more than just allow quantification of the errors associated with the use of linear models. It also offers the possibility of propagation modeling and acoustic inversions which appropriately incorporate the bubble nonlinearity. Furthermore, it allows exploration and quantification of possible nonlinear effects which may be exploited. As a result, high acoustic pressure amplitudes may be desirable even in low void fractions, because they offer opportunities to gain information about the bubble cloud from the nonlinearities, and options to exploit the nonlinearities to enhance communication and sonar in bubbly waters. This paper presents a method for calculating the nonlinear acoustic cross-sections, scatter, attenuations and sound speeds from bubble clouds which may be inhomogeneous. The method allows prediction of the time dependency of these quantities, both because the cloud may vary and because the incident acoustic pulse may have finite and arbitrary time history. The method can be readily adapted for bubbles in other environments (e.g. clouds of interacting bubbles, sediments, structures, in vivo, reverberant conditions etc.). The possible exploitation of bubble acoustics by marine mammals, and for sonar enhancement, is explored.

  17. Application of ozone micro-nano-bubbles to groundwater remediation.

    Science.gov (United States)

    Hu, Liming; Xia, Zhiran

    2018-01-15

    Ozone is widely used for water treatment because of its strong oxidation ability. However, the efficiency of ozone in groundwater remediation is limited because of its relatively low solubility and rapid decomposition in the aqueous phase. Methods for increasing the stability of ozone within the subsurface are drawing increasing attention. Micro-nano-bubbles (MNBs), with diameters ranging from tens of nanometres to tens of micrometres, present rapid mass transfer rates, persist for a relatively long time in water, and transport with groundwater flow, which significantly improve gas concentration and provide a continuous gas supply. Therefore, MNBs show a considerable potential for application in groundwater remediation. In this study, the characteristics of ozone MNBs were examined, including their size distribution, bubble quantity, and zeta potential. The mass transfer rate of ozone MNBs was experimentally investigated. Ozone MNBs were then used to treat organics-contaminated water, and they showed remarkable cleanup efficiency. Column tests were also conducted to study the efficiency of ozone MNBs for organics-contaminated groundwater remediation. Based on the laboratory tests, field monitoring was conducted on a trichloroethylene (TCE)-contaminated site. The results showed that ozone MNBs can greatly improve remediation efficiency and represent an innovative technology for in situ remediation of organics-contaminated groundwater. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  18. Galactic Teamwork Makes Distant Bubbles

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    During the period of reionization that followed the dark ages of our universe, hydrogen was transformed from a neutral state, which is opaque to radiation, to an ionized one, which is transparent to radiation. But what generated the initial ionizing radiation? The recent discovery of multiple distant galaxies offers evidence for how this process occurred.Two Distant GalaxiesWe believe reionization occurred somewhere between a redshift of z = 6 and 7, because Ly-emitting galaxies drop out at roughly this redshift. Beyond this distance, were generally unable to see the light from these galaxies, because the universe is no longer transparent to their emission. This is not always the case, however: if a bubble of ionized gas exists around a distant galaxy, the radiation can escape, allowing us to see the galaxy.This is true of two recently-discovered Ly-emitting galaxies, confirmed to be at a redshift of z~7 and located near one another in a region known as the Bremer Deep Field. The fact that were able to see the radiation from these galaxies means that they are in an ionized HII region presumably one of the earlier regions to have become reionized in the universe.But on their own, neither of these galaxies is capable of generating an ionized bubble large enough for their light to escape. So what ionized the region around them, and what does this mean for our understanding of how reionization occurred in the universe?A Little Help From FriendsLocation in different filters of the objects in the Hubble Bremer Deep Field catalog. The z~7 selection region is outlined by the grey box. BDF-521 and BDF-3299 were the two originally discovered galaxies; the remaining red markers indicate the additional six galaxies discovered in the same region. [Castellano et al. 2016]A team of scientists led by Marco Castellano (Rome Observatory, INAF) investigated the possibility that there are other, faint galaxies near these two that have helped to ionize the region. Performing a survey

  19. Revising the Local Bubble Model due to Solar Wind Charge Exchange X-ray Emission

    Science.gov (United States)

    Shelton, Robin L.

    2009-03-01

    The hot Local Bubble surrounding the solar neighborhood has been primarily studied through observations of its soft X-ray emission. The measurements were obtained by attributing all of the observed local soft X-rays to the bubble. However, mounting evidence shows that the heliosphere also produces diffuse X-rays. The source is solar wind ions that have received an electron from another atom. The presence of this alternate explanation for locally produced diffuse X-rays calls into question the existence and character of the Local Bubble. This article addresses these questions. It reviews the literature on solar wind charge exchange (SWCX) X-ray production, finding that SWCX accounts for roughly half of the observed local 1/4 keV X-rays found at low latitudes. This article also makes predictions for the heliospheric O VI column density and intensity, finding them to be smaller than the observational error bars. Evidence for the continued belief that the Local Bubble contains hot gas includes the remaining local 1/4 keV intensity, the observed local O VI column density, and the need to fill the local region with some sort of plasma. If the true Local Bubble is half as bright as previously thought, then its electron density and thermal pressure are 1/sqrt{2} as great as previously thought, and its energy requirements and emission measure are 1/2 as great as previously thought. These adjustments can be accommodated easily, and, in fact, bring the Local Bubble’s pressure more in line with that of the adjacent material. Suggestions for future work are made.

  20. Impact of bubble wakes on a developing bubble flow in a vertical pipe

    International Nuclear Information System (INIS)

    Tomiyama, A.; Makino, Y.; Miyoshi, K.; Tamai, H.; Serizawa, A.; Zun, I.

    1998-01-01

    Three-dimensional two-way bubble tracking simulation of single large air bubbles rising through a stagnant water filled in a vertical pipe was conducted to investigate the structures of bubble wakes. Spatial distributions of time-averaged liquid velocity field, turbulent intensity and Reynolds stress caused by bubble wakes were deduced from the calculated local instantaneous liquid velocities. It was confirmed that wake structures are completely different from the ones estimated by a conventional wake model. Then, we developed a simple wake model based on the predicted time-averaged wake velocity fields, and implemented it into a 3D one-way bubble tracking method to examine the impact of bubble wake structures on time-spatial evolution of a developing air-water bubble flow in a vertical pipe. As a results, we confirmed that the developed wake model can give better prediction for flow pattern evolution than a conventional wake model

  1. Externally triggered renewed bubble nucleation in basaltic magma: the 12 October 2008 eruption at Halema‘uma‘u Overlook vent, Kīlauea, Hawai‘i, USA

    Science.gov (United States)

    Carey, Rebecca J.; Manga, Michael; Degruyter, Wim; Swanson, Donald; Houghton, Bruce F.; Orr, Tim R.; Patrick, Matthew R.

    2012-01-01

    From October 2008 until present, dozens of small impulsive explosive eruptions occurred from the Overlook vent on the southeast side of Halema‘uma‘u Crater, at Kīlauea volcano, USA. These eruptions were triggered by rockfalls from the walls of the volcanic vent and conduit onto the top of the lava column. Here we use microtextural observations and data from clasts erupted during the well-characterized 12 October 2008 explosive eruption at Halema‘uma‘u to extend existing models of eruption triggering. We present a potential mechanism for this eruption by combining microtextural observations with existing geophysical and visual data sets. We measure the size and number density of bubbles preserved in juvenile ejecta using 2D images and X-ray microtomography. Our data suggest that accumulations of large bubbles with diameters of >50μm to at least millimeters existed at shallow levels within the conduit prior to the 12 October 2008 explosion. Furthermore, a high number density of small bubbles nucleation of bubbles. Visual observations, combined with preexisting geophysical data, suggest that the impact of rockfalls onto the magma free surface induces pressure changes over short timescales that (1) nucleated new additional bubbles in the shallow conduit leading to high number densities of small bubbles and (2) expanded the preexisting bubbles driving upward acceleration. The trigger of eruption and bubble nucleation is thus external to the degassing system.

  2. Single DNA denaturation and bubble dynamics

    DEFF Research Database (Denmark)

    Metzler, Ralf; Ambjörnsson, Tobias; Hanke, Andreas

    2009-01-01

    While the Watson-Crick double-strand is the thermodynamically stable state of DNA in a wide range of temperature and salt conditions, even at physiological conditions local denaturation bubbles may open up spontaneously due to thermal activation. By raising the ambient temperature, titration......, or by external forces in single molecule setups bubbles proliferate until full denaturation of the DNA occurs. Based on the Poland-Scheraga model we investigate both the equilibrium transition of DNA denaturation and the dynamics of the denaturation bubbles with respect to recent single DNA chain experiments...... for situations below, at, and above the denaturation transition. We also propose a new single molecule setup based on DNA constructs with two bubble zones to measure the bubble coalescence and extract the physical parameters relevant to DNA breathing. Finally we consider the interplay between denaturation...

  3. Oscillation of large air bubble cloud

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Y.Y.; Kim, H.Y.; Park, J.K. [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

    2001-07-01

    The behavior of a large air bubble cloud, which is generated by the air discharged from a perforated sparger, is analyzed by solving Rayleigh-Plesset equation, energy equations and energy balance equation. The equations are solved by Runge-Kutta integration and MacCormack finite difference method. Initial conditions such as driving pressure, air volume, and void fraction strongly affect the bubble pressure amplitude and oscillation frequency. The pool temperature has a strong effect on the oscillation frequency and a negligible effect on the pressure amplitude. The polytropic constant during the compression and expansion processes of individual bubbles ranges from 1.0 to 1.4, which may be attributed to the fact that small bubbles oscillated in frequencies different from their resonance. The temperature of the bubble cloud rapidly approaches the ambient temperature, as is expected from the polytropic constants being between 1.0 and 1.4. (authors)

  4. Oscillation of large air bubble cloud

    International Nuclear Information System (INIS)

    Bae, Y.Y.; Kim, H.Y.; Park, J.K.

    2001-01-01

    The behavior of a large air bubble cloud, which is generated by the air discharged from a perforated sparger, is analyzed by solving Rayleigh-Plesset equation, energy equations and energy balance equation. The equations are solved by Runge-Kutta integration and MacCormack finite difference method. Initial conditions such as driving pressure, air volume, and void fraction strongly affect the bubble pressure amplitude and oscillation frequency. The pool temperature has a strong effect on the oscillation frequency and a negligible effect on the pressure amplitude. The polytropic constant during the compression and expansion processes of individual bubbles ranges from 1.0 to 1.4, which may be attributed to the fact that small bubbles oscillated in frequencies different from their resonance. The temperature of the bubble cloud rapidly approaches the ambient temperature, as is expected from the polytropic constants being between 1.0 and 1.4. (authors)

  5. Mesoporous hollow spheres from soap bubbling.

    Science.gov (United States)

    Yu, Xianglin; Liang, Fuxin; Liu, Jiguang; Lu, Yunfeng; Yang, Zhenzhong

    2012-02-01

    The smaller and more stable bubbles can be generated from the large parent bubbles by rupture. In the presence of a bubble blowing agent, hollow spheres can be prepared by bubbling a silica sol. Herein, the trapped gas inside the bubble acts as a template. When the porogen, i.e., other surfactant, is introduced, a mesostructured shell forms by the co-assembly with the silica sol during sol-gel process. Morphological evolution emphasizes the prerequisite of an intermediate interior gas flow rate and high exterior gas flow rate for hollow spheres. The method is valid for many compositions from inorganic, polymer to their composites. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Structure and kinematics of bubble flow

    International Nuclear Information System (INIS)

    Lackme, C.

    1967-01-01

    This report deals with the components and use of resistivity probes in bubble flow. With a single probe, we have studied the longitudinal and radial structure of the flow. The very complicated evolution of the radial structure is shown by the measurement of the mean bubble flux at several points in the tube. A double probe associated with a device the principle of which is given in this report, permits the measure of the local velocity of bubbles. Unlike the mean bubble flux profile, the change in the velocity profile along the tube is not significant. We have achieved the synthesis of these two pieces of information, mean local bubble flux and local velocity, by computing the mean weighed velocity in the tube. This weighed velocity compares remarkably with the velocity computed from the volumetric gas flow rate and the mean void fraction. (author) [fr

  7. Interaction mechanism of double bubbles in hydrodynamic cavitation

    Science.gov (United States)

    Li, Fengchao; Cai, Jun; Huai, Xiulan; Liu, Bin

    2013-06-01

    Bubble-bubble interaction is an important factor in cavitation bubble dynamics. In this paper, the dynamic behaviors of double cavitation bubbles driven by varying pressure field downstream of an orifice plate in hydrodynamic cavitation reactor are examined. The bubble-bubble interaction between two bubbles with different radii is considered. We have shown the different dynamic behaviors between double cavitation bubbles and a single bubble by solving two coupling nonlinear equations using the Runge-Kutta fourth order method with adaptive step size control. The simulation results indicate that, when considering the role of the neighbor smaller bubble, the oscillation of the bigger bubble gradually exhibits a lag in comparison with the single-bubble case, and the extent of the lag becomes much more obvious as time goes by. This phenomenon is more easily observed with the increase of the initial radius of the smaller bubble. In comparison with the single-bubble case, the oscillation of the bigger bubble is enhanced by the neighbor smaller bubble. Especially, the pressure pulse of the bigger bubble rises intensely when the sizes of two bubbles approach, and a series of peak values for different initial radii are acquired when the initial radius ratio of two bubbles is in the range of 0.9˜1.0. Although the increase of the center distance between two bubbles can weaken the mutual interaction, it has no significant influence on the enhancement trend. On the one hand, the interaction between two bubbles with different radii can suppress the growth of the smaller bubble; on the other hand, it also can enhance the growth of the bigger one at the same time. The significant enhancement effect due to the interaction of multi-bubbles should be paid more attention because it can be used to reinforce the cavitation intensity for various potential applications in future.

  8. Semi-industrial experimental study on bauxite separation using a cell-column integration process

    Science.gov (United States)

    Zhang, Ning-ning; Zhou, Chang-chun; Cong, Long-fei; Cao, Wen-long; Zhou, You

    2016-01-01

    The cyclonic-static micro-bubble flotation column (FCSMC) is a highly efficient mineral processing equipment. In this study, a cell-column (FCSMC) integration process was investigated for the separation of bauxite and its feasibility was analyzed on a theoretical basis. The properties of low-grade bauxite ore from Henan Province, China were analyzed. Parameters such as reagent dosage, scraping bubble time, and pressure of the circulating pump during the sorting process were investigated and optimized to improve the flotation efficiency. On the basis of these parameters, continuous separation experiments were conducted. Bauxite concentrate with an aluminum-to-silicon (A/S) mass ratio of 6.37 and a 77.63wt% recovery rate were achieved via a flow sheet consisting of "fast flotation using a flotation cell, one roughing flotation and one cleaning flotation using flotation columns". Compared with the full-flotation-cells process, the cell-column integration process resulted in an increase of the A/S ratio by 0.41 and the recovery rate by 17.58wt%. Cell-column integration separation technology represents a new approach for the separation of middle-to-low-grade bauxite ore.

  9. Safety barriers and lighting columns.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1972-01-01

    Problems arising from the sitting of lighting columns on the central reserve are reviewed, and remedial measures such as break-away lighting supports and installation of safety fences on the central reserve on both sides of the lighting columns are examined.

  10. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  11. Legacies of the bubble chamber

    International Nuclear Information System (INIS)

    Mulvey, J.H.

    1994-01-01

    Legacies are what we pass on to those who follow us, the foundations on which the next advances in our science are being made; the things by which we shall be remembered, recorded in learned journals, written in the text books -food for the historians of science. This is not a summary, and it will draw no conclusions. It is a personal view which will look a little wider than the main physics results to include a mention of one or two of the technologies and methods handed on to both particle physics and other branches of sciences, a brief reference to bubble chamber pictures as aids in teaching, and a comment on the challenge now increasingly applied in the UK - and perhaps elsewhere -as a criterion for funding research: will it contribute to ''wealth creation''? (orig.)

  12. An experimental propane bubble chamber

    International Nuclear Information System (INIS)

    Rogozinski, A.

    1957-01-01

    Describes a propane bubble chamber 10 cm in diameter and 5 cm deep. The body of the chamber is in stainless steel, and it has two windows of polished hardened glass. The compression and decompression of the propane are performed either through a piston in direct contact with the liquid, or by the action on the liquid, through a triple-mylar-Perbunan membrane, of a compressed gas. The general and also optimum working conditions of the chamber are described, and a few results are given concerning, in particular, the tests of the breakage-resistance of the windows and the measurements of the thermal expansion of the compressibility isotherm for the propane employed. (author) [fr

  13. Numerical modeling of bubble dynamics in magmas

    Science.gov (United States)

    Huber, Christian; Su, Yanqing; Parmigiani, Andrea

    2014-05-01

    Understanding the complex non-linear physics that governs volcanic eruptions is contingent on our ability to characterize the dynamics of bubbles and its effect on the ascending magma. The exsolution and migration of bubbles has also a great impact on the heat and mass transport in and out of magma bodies stored at shallow depths in the crust. Multiphase systems like magmas are by definition heterogeneous at small scales. Although mixture theory or homogenization methods are convenient to represent multiphase systems as a homogeneous equivalent media, these approaches do not inform us on possible feedbacks at the pore-scale and can be significantly misleading. In this presentation, we discuss the development and application of bubble-scale multiphase flow modeling to address the following questions : How do bubbles impact heat and mass transport in magma chambers ? How efficient are chemical exchanges between the melt and bubbles during magma decompression? What is the role of hydrodynamic interactions on the deformation of bubbles while the magma is sheared? Addressing these questions requires powerful numerical methods that accurately model the balance between viscous, capillary and pressure stresses. We discuss how these bubble-scale models can provide important constraints on the dynamics of magmas stored at shallow depth or ascending to the surface during an eruption.

  14. Performance Tests for Bubble Blockage Device

    International Nuclear Information System (INIS)

    Ha, Kwang Soon; Wi, Kyung Jin; Park, Rae Joon; Wan, Han Seong

    2014-01-01

    Postulated severe core damage accidents have a high threat risk for the safety of human health and jeopardize the environment. Versatile measures have been suggested and applied to mitigate severe accidents in nuclear power plants. To improve the thermal margin for the severe accident measures in high-power reactors, engineered corium cooling systems involving boiling-induced two-phase natural circulation have been proposed for decay heat removal. A boiling-induced natural circulation flow is generated in a coolant path between a hot vessel wall and cold coolant reservoir. In general, it is possible for some bubbles to be entrained in the natural circulation loop. If some bubbles entrain in the liquid phase flow passage, flow instability may occur, that is, the natural circulation mass flow rate may be oscillated. A new device to block the entraining bubbles is proposed and verified using air-water test loop. To avoid bubbles entrained in the natural circulation flow loop, a new device was proposed and verified using an air-water test loop. The air injection and liquid circulation loop was prepared, and the tests for the bubble blockage devices were performed by varying the geometry and shape of the devices. The performance of the bubble blockage device was more effective as the area ratio of the inlet to the down-comer increased, and the device height decreased. If the device has a rim to generate a vortex zone, the bubbles will be most effectively blocked

  15. Bubbles in the self-accelerating universe

    International Nuclear Information System (INIS)

    Izumi, Keisuke; Tanaka, Takahiro; Koyama, Kazuya; Pujolas, Oriol

    2007-01-01

    We revisit the issue of the stability in the Dvali-Gabadadze-Porrati model by considering the nucleation of bubbles of the conventional branch within the self-accelerating branch. We construct an instanton describing this process in the thin wall approximation. On one side of the bubble wall, the bulk consists of the exterior of the brane, while on the other side it is the interior. The solution requires the presence of a 2-brane (the bubble wall) which induces the transition. However, we show that this instanton cannot be realized as the thin wall limit of any smooth solution. Once the bubble thickness is resolved, the equations of motion do not allow O(4) symmetric solutions joining the two branches. We conclude that the thin wall instanton is unphysical, and that one cannot have processes connecting the two branches, unless negative tension bubble walls are introduced. This also suggests that the self-accelerating branch does not decay into the conventional branch nucleating bubbles. We comment on other kinds of bubbles that could interpolate between the two branches

  16. Average properties of bidisperse bubbly flows

    Science.gov (United States)

    Serrano-García, J. C.; Mendez-Díaz, S.; Zenit, R.

    2018-03-01

    Experiments were performed in a vertical channel to study the properties of a bubbly flow composed of two distinct bubble size species. Bubbles were produced using a capillary bank with tubes with two distinct inner diameters; the flow through each capillary size was controlled such that the amount of large or small bubbles could be controlled. Using water and water-glycerin mixtures, a wide range of Reynolds and Weber number ranges were investigated. The gas volume fraction ranged between 0.5% and 6%. The measurements of the mean bubble velocity of each species and the liquid velocity variance were obtained and contrasted with the monodisperse flows with equivalent gas volume fractions. We found that the bidispersity can induce a reduction of the mean bubble velocity of the large species; for the small size species, the bubble velocity can be increased, decreased, or remain unaffected depending of the flow conditions. The liquid velocity variance of the bidisperse flows is, in general, bound by the values of the small and large monodisperse values; interestingly, in some cases, the liquid velocity fluctuations can be larger than either monodisperse case. A simple model for the liquid agitation for bidisperse flows is proposed, with good agreement with the experimental measurements.

  17. The Minnaert bubble: an acoustic approach

    Energy Technology Data Exchange (ETDEWEB)

    Devaud, Martin; Hocquet, Thierry; Bacri, Jean-Claude [Laboratoire Matiere et Systemes Complexes, Universite Paris Diderot and CNRS UMR 7057, 10 rue Alice Domont et Leonie Duquet, 75013 Paris (France); Leroy, Valentin [Laboratoire Ondes et Acoustique, Universite Paris 7 and CNRS UMR 7587, ESPCI, 10 rue Vauquelin, 75005 Paris (France)], E-mail: martin.devaud@univ-paris-diderot.fr

    2008-11-15

    We propose an ab initio introduction to the well-known Minnaert pulsating bubble at graduate level. After a brief recall of the standard stuff, we begin with a detailed discussion of the radial movements of an air bubble in water. This discussion is managed from an acoustic point of view, and using the Lagrangian rather than the Eulerian variables. In unbounded water, the air-water system has a continuum of eigenmodes, some of them correspond to regular Fabry-Perot resonances. A singular resonance, the lowest one, is shown to coincide with that of Minnaert. In bounded water, the eigenmodes spectrum is discrete, with a finite fundamental frequency. A spectacular quasi-locking of the latter occurs if it happens to exceed the Minnaert frequency, which provides an unforeseen one-bubble alternative version of the famous 'hot chocolate effect'. In the (low) frequency domain in which sound propagation inside the bubble reduces to a simple 'breathing' (i.e. inflation/deflation), the light air bubble can be 'dressed' by the outer water pressure forces, and is turned into the heavy Minnaert bubble. Thanks to this unexpected renormalization process, we demonstrate that the Minnaert bubble definitely behaves like a true harmonic oscillator of the spring-bob type, but with a damping term and a forcing term in apparent disagreement with those commonly admitted in the literature. Finally, we underline the double role played by the water. In order to tell the water motion associated with water compressibility (i.e. the sound) from the simple incompressible accompaniment of the bubble breathing, we introduce a new picture analogous to the electromagnetic radiative picture in Coulomb gauge, which naturally leads us to split the water displacement in an instantaneous and a retarded part. The Minnaert renormalized mass of the dressed bubble is then automatically recovered.

  18. Pressure waves in a supersaturated bubbly magma

    Science.gov (United States)

    Kurzon, I.; Lyakhovsky, V.; Navon, O.; Chouet, B.

    2011-01-01

    We study the interaction of acoustic pressure waves with an expanding bubbly magma. The expansion of magma is the result of bubble growth during or following magma decompression and leads to two competing processes that affect pressure waves. On the one hand, growth in vesicularity leads to increased damping and decreased wave amplitudes, and on the other hand, a decrease in the effective bulk modulus of the bubbly mixture reduces wave velocity, which in turn, reduces damping and may lead to wave amplification. The additional acoustic energy originates from the chemical energy released during bubble growth. We examine this phenomenon analytically to identify conditions under which amplification of pressure waves is possible. These conditions are further examined numerically to shed light on the frequency and phase dependencies in relation to the interaction of waves and growing bubbles. Amplification is possible at low frequencies and when the growth rate of bubbles reaches an optimum value for which the wave velocity decreases sufficiently to overcome the increased damping of the vesicular material. We examine two amplification phase-dependent effects: (1) a tensile-phase effect in which the inserted wave adds to the process of bubble growth, utilizing the energy associated with the gas overpressure in the bubble and therefore converting a large proportion of this energy into additional acoustic energy, and (2) a compressive-phase effect in which the pressure wave works against the growing bubbles and a large amount of its acoustic energy is dissipated during the first cycle, but later enough energy is gained to amplify the second cycle. These two effects provide additional new possible mechanisms for the amplification phase seen in Long-Period (LP) and Very-Long-Period (VLP) seismic signals originating in magma-filled cracks.

  19. Lifetime of Bubble Rafts: Cooperativity and Avalanches

    Science.gov (United States)

    Ritacco, Hernán; Kiefer, Flavien; Langevin, Dominique

    2007-06-01

    We have studied the collapse of pseudo-bi-dimensional foams. These foams are made of uniformly sized soap bubbles packed in an hexagonal lattice sitting at the top of a liquid surface. The collapse process follows the sequence: (1) rupture of a first bubble, driven by thermal fluctuations and (2) a cascade of bursting bubbles. We present a simple numerical model which captures the main characteristics of the dynamics of foam collapse. We show that in a certain range of viscosities of the foaming solutions, the size distribution of the avalanches follows power laws as in self-organized criticality processes.

  20. Decay of bubble of disoriented chiral condensate

    International Nuclear Information System (INIS)

    Gani, V.A.; Kudryavtsev, A.E.; Belova, T.I.

    1999-01-01

    The space-time structure for the process of decay of a bubble of hypothetical phase -disoriented chiral condensate (DCC) i discussed. The evolution of the initial classical field configuration corresponding to the bubble of DCC is studied, both numerically and analytically. The decay of this initial configuration depends crucially on self-interaction of the pionic fields. It is shown that in some cases this self-interaction leads to the formation of sort of breather solution, formed from pionic fields situated in the center of the initial bubble of DCC. This breather looks like a long-lived source of pionic fields [ru

  1. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An

  2. Dechanneling of particles by gas bubbles

    International Nuclear Information System (INIS)

    Ronikier-Polonsky, Danuta.

    1976-01-01

    The dechanneling probability P of a particle hitting a gas bubble in a solid is evaluated theoretically. This probability is found to depend neither on the energy of the particle, nor on the radius of the bubble. A simple expression of P is given in the case of a harmonic channeling potential. Then an experiment is described concerning α particles channeled along (111) planes in aluminium containing helium bubbles. In this particular case, the measured probabilitity (P=0.27+-0.09) is in good agreement with the corresponding theoretical values (0.34 for a harmonic potential and 0.24 for a more realistic potential) [fr

  3. Experimental observation of exploding electron bubbles

    International Nuclear Information System (INIS)

    Classen, J.; Su, C.K.; Hall, S.C.; Pettersen, M.S.; Maris, H.J.

    1996-01-01

    Since free electrons form small voids in liquid helium they are expected to be preferred sites for nucleating macroscopic bubbles when the liquid is exposed to sufficiently large negative pressures. We have performed a series of cavitation experiments using focussed ultrasound where free electrons were introduced into the liquid by a radioactive source. The electron bubbles are found to explode at negative pressures significantly lower than those required for homogeneous nucleation. We present measurements of the thresholds for cavitation at electrons in the temperature range 1 - 4.5 K. Reasonable agreement with a simple model for the stability limit of the electron bubble is obtained. (author)

  4. A view inside the Gargamelle bubble chamber

    CERN Multimedia

    1970-01-01

    Gargamelle was the name given to a big bubble chamber built at the Saclay Laboratory in France during the late 1960s. It was designed principally for the detection at CERN of the elusive particles called neutrinos. A bubble chamber contains a liquid under pressure, which reveals the tracks of electrically charged particles as trails of tiny bubbles when the pressure is reduced. Neutrinos have no charge, and so leave no tracks, but the aim with Gargamelle was "see neutrinos" by making visible any charged particles set in motion by the interaction of neutrinos in the liquid

  5. A model established of a 'Embryo' bubble growing-up some visible bubble in bubble chamber and its primary theory calculation

    International Nuclear Information System (INIS)

    Ye Zipiao; Sheng Xiangdong

    2006-01-01

    A model of a 'embryo' bubble growing up a visible bubble in the bubble chamber is established. Through primary theory calculation it is shown that the 'embryo' bubble is not only absorbing quantity of heat, but also some molecules get into the 'embryo' bubble from its environment. It is explained reasonably that the radius of bubbles in bubble camber is different for the same energies of neutrons and proton. The track of neutron in bubble camber is long and thin, and the track of proton in bubble camber is wide and short. It is explained reasonably that the bubble radius of the incident particles with more charges which there are the same energies will be wider than that of the incident particles with less charges in the track. It is also explained reasonably that there are a little different radius of the bubbles of a track at the some region. It can be predicted theoretically that there should be big bubbles to burst when incident particles enter the bubble chamber at first. The sensitivity and the detective efficiency of bubble camber can be enhanced by choosing appropriate work matter. (authors)

  6. Bubbles, Bubbles, Tremors & Trouble: The Bayou Corne Sinkhole

    Science.gov (United States)

    Nunn, J. A.

    2013-12-01

    In May 2012, thermogenic methane bubbles were first observed in Bayou Corne in Assumption Parish, Louisiana. As of July 2013, ninety one bubbling sites have been identified. Gas was also found in the top of the Mississippi River Alluvial Aquifer (MRAA) about 125 ft below the surface. Vent wells drilled into the MRAA have flared more 16 million SCF of gas. Trace amounts of hydrogen sulfide also have been detected. Bayou Corne flows above the Napoleonville salt dome which has been an active area for oil and gas exploration since the 1920s. The dome is also a site of dissolution salt mining which has produced large caverns with diameters of up to 300 ft and heights of 2000 ft. Some caverns are used for storage of natural gas. Microseismic activity was confirmed by an Earthscope seismic station in White Castle, LA in July 2012. An array of microseismic stations set up in the area recorded more than 60 microseismic events in late July and early August, 2012. These microseismic events were located on the western side of the dome. Estimated focal depths are just above the top of salt. In August 2012, a sinkhole developed overnight just to the northwest of a plugged and abandoned brine filled cavern (see figure below). The sinkhole continues to grow in area to more than 20 acres and has consumed a pipeline right of way. The sinkhole is more than 750 ft deep at its center. Microseismic activity was reduced for several months following the formation of the sinkhole. Microseismic events have reoccurred episodically since then with periods of frequent events preceding slumping of material into the sinkhole or a 'burp' where fluid levels in the sinkhole drop and then rebound followed by a decrease in microseismic activity. Some gas and/or oil may appear at the surface of the sinkhole following a 'burp'. Very long period events also have been observed which are believed to be related to subsurface fluid movement. A relief well drilled into the abandoned brine cavern found that

  7. Column-Oriented Database Systems (Tutorial)

    NARCIS (Netherlands)

    D. Abadi; P.A. Boncz (Peter); S. Harizopoulos

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as

  8. Stability of a Bubble Expanding and Translating Through an Inviscid ...

    Indian Academy of Sciences (India)

    A bubble expands adiabatically and translates in an incompressible and inviscid liquid. We investigate the number of equilibrium points of the bubble and the nature of stability of the bubble at these points. We find that there is only one equilibrium point and the bubble is stable there.

  9. Fluctuation effects on bubble growth in hot nuclear matter

    International Nuclear Information System (INIS)

    Santiago, A.J.; Chung, K.C.

    1991-01-01

    The evolution of bubbles with arbitrary density in an infinite nuclear system is studied in a simplified treatment. Kinetic pressure fluctuations on the bubble surface are considered. The critical radius, evolution time and probability for bubble expansion are shown to depend significantly on the initial bubble density. (author)

  10. A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders: Examples from the Arctic offshore NW-Svalbard

    NARCIS (Netherlands)

    Veloso, M.; Greinert, J.; Mienert, J.; De Batist, M.

    2015-01-01

    Quantifying marine methane fluxes of free gas (bubbles) from the seafloor into the water column is of importance for climate related studies, for example, in the Arctic, reliable methodologies are also of interest for studying man-made gas and oil leakage systems at hydrocarbon production sites.

  11. IMPLEMENTATION OF SERIAL AND PARALLEL BUBBLE SORT ON FPGA

    Directory of Open Access Journals (Sweden)

    Dwi Marhaendro Jati Purnomo

    2016-06-01

    Full Text Available Sorting is common process in computational world. Its utilization are on many fields from research to industry. There are many sorting algorithm in nowadays. One of the simplest yet powerful is bubble sort. In this study, bubble sort is implemented on FPGA. The implementation was taken on serial and parallel approach. Serial and parallel bubble sort then compared by means of its memory, execution time, and utility which comprises slices and LUTs. The experiments show that serial bubble sort required smaller memory as well as utility compared to parallel bubble sort. Meanwhile, parallel bubble sort performed faster than serial bubble sort

  12. Generation of a bubble universe using a negative energy bath

    International Nuclear Information System (INIS)

    Hwang, Dong-il; Yeom, Dong-han

    2011-01-01

    This paper suggests a model for a bubble universe using buildable false vacuum bubbles. We study the causal structures of collapsing false vacuum bubbles using double-null simulations. False vacuum bubbles violate the null energy condition and emit negative energy along the outgoing direction through semi-classical effects. If there are a few collapsing false vacuum bubbles and they emit negative energy to a certain region, then the region can be approximated by a negative energy bath, which means that the region is homogeneously filled by negative energy. If a false vacuum bubble is generated in the negative energy bath and the tension of the bubble effectively becomes negative in the bath, then the bubble can expand and form an inflating bubble universe. This scenario uses a set of assumptions different from those in previous studies because it does not require tunneling to unbuildable bubbles.

  13. Effect of supercritical water shell on cavitation bubble dynamics

    International Nuclear Information System (INIS)

    Shao Wei-Hang; Chen Wei-Zhong

    2015-01-01

    Based on reported experimental data, a new model for single cavitation bubble dynamics is proposed considering a supercritical water (SCW) shell surrounding the bubble. Theoretical investigations show that the SCW shell apparently slows down the oscillation of the bubble and cools the gas temperature inside the collapsing bubble. Furthermore, the model is simplified to a Rayleigh–Plesset-like equation for a thin SCW shell. The dependence of the bubble dynamics on the thickness and density of the SCW shell is studied. The results show the bubble dynamics depends on the thickness but is insensitive to the density of the SCW shell. The thicker the SCW shell is, the smaller are the wall velocity and the gas temperature in the bubble. In the authors’ opinion, the SCW shell works as a buffering agent. In collapsing, it is compressed to absorb a good deal of the work transformed into the bubble internal energy during bubble collapse so that it weakens the bubble oscillations. (paper)

  14. Lattice Boltzmann Simulation of Multiple Bubbles Motion under Gravity

    Directory of Open Access Journals (Sweden)

    Deming Nie

    2015-01-01

    Full Text Available The motion of multiple bubbles under gravity in two dimensions is numerically studied through the lattice Boltzmann method for the Eotvos number ranging from 1 to 12. Two kinds of initial arrangement are taken into account: vertical and horizontal arrangement. In both cases the effects of Eotvos number on the bubble coalescence and rising velocity are investigated. For the vertical arrangement, it has been found that the coalescence pattern is similar. The first coalescence always takes place between the two uppermost bubbles. And the last coalescence always takes place between the coalesced bubble and the bottommost bubble. For four bubbles in a horizontal arrangement, the outermost bubbles travel into the wake of the middle bubbles in all cases, which allows the bubbles to coalesce. The coalescence pattern is more complex for the case of eight bubbles, which strongly depends on the Eotvos number.

  15. Letter: Entrapment and interaction of an air bubble with an oscillating cavitation bubble

    Science.gov (United States)

    Kannan, Y. S.; Karri, Badarinath; Sahu, Kirti Chandra

    2018-04-01

    The mechanism of the formation of an air bubble due to an oscillating cavitation bubble in its vicinity is reported from an experimental study using high-speed imaging. The cavitation bubble is created close to the free surface of water using a low-voltage spark circuit comprising two copper electrodes in contact with each other. Before the bubble is created, a third copper wire is positioned in contact with the free surface of water close to the two crossing electrodes. Due to the surface tension at the triple point (wire-water-air) interface, a small dip is observed in the free surface at the point where the wire is immersed. When the cavitation bubble is created, the bubble pushes at the dip while expanding and pulls at it while collapsing. The collapse phase leads to the entrapment of an air bubble at the wire immersion point. During this phase, the air bubble undergoes a "catapult" effect, i.e., it expands to a maximum size and then collapses with a microjet at the free surface. To the best of our knowledge, this mechanism has not been reported so far. A parametric study is also conducted to understand the effects of wire orientation and bubble distance from the free surface.

  16. How are soap bubbles blown? Fluid dynamics of soap bubble blowing

    Science.gov (United States)

    Davidson, John; Lambert, Lori; Sherman, Erica; Wei, Timothy; Ryu, Sangjin

    2013-11-01

    Soap bubbles are a common interfacial fluid dynamics phenomenon having a long history of delighting not only children and artists but also scientists. In contrast to the dynamics of liquid droplets in gas and gas bubbles in liquid, the dynamics of soap bubbles has not been well documented. This is possibly because studying soap bubbles is more challenging due to there existing two gas-liquid interfaces. Having the thin-film interface seems to alter the characteristics of the bubble/drop creation process since the interface has limiting factors such as thickness. Thus, the main objective of this study is to determine how the thin-film interface differentiates soap bubbles from gas bubbles and liquid drops. To investigate the creation process of soap bubbles, we constructed an experimental model consisting of air jet flow and a soap film, which consistently replicates the conditions that a human produces when blowing soap bubbles, and examined the interaction between the jet and the soap film using the high-speed videography and the particle image velocimetry.

  17. Optimization of the bubble radius in a moving single bubble sonoluminescence

    International Nuclear Information System (INIS)

    Mirheydari, Mona; Sadighi-Bonabi, Rasoul; Rezaee, Nastaran; Ebrahimi, Homa

    2011-01-01

    A complete study of the hydrodynamic force on a moving single bubble sonoluminescence in N-methylformamide is presented in this work. All forces exerted, trajectory, interior temperature and gas pressure are discussed. The maximum values of the calculated components of the hydrodynamic force for three different radii at the same driving pressure were compared, while the optimum bubble radius was determined. The maximum value of the buoyancy force appears at the start of bubble collapse, earlier than the other forces whose maximum values appear at the moment of bubble collapse. We verified that for radii larger than the optimum radius, the temperature peak value decreases.

  18. Water Column Sonar Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  19. Bubble collisions and measures of the multiverse

    International Nuclear Information System (INIS)

    Salem, Michael P.

    2012-01-01

    To compute the spectrum of bubble collisions seen by an observer in an eternally-inflating multiverse, one must choose a measure over the diverging spacetime volume, including choosing an ''initial'' hypersurface below which there are no bubble nucleations. Previous calculations focused on the case where the initial hypersurface is pushed arbitrarily deep into the past. Interestingly, the observed spectrum depends on the orientation of the initial hypersurface, however one's ability observe the effect rapidly decreases with the ratio of inflationary Hubble rates inside and outside one's bubble. We investigate whether this conclusion might be avoided under more general circumstances, including placing the observer's bubble near the initial hypersurface. We find that it is not. As a point of reference, a substantial appendix reviews relevant aspects of the measure problem of eternal inflation

  20. Bubble collisions and measures of the multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Michael P., E-mail: salem@cosmos.phy.tufts.edu [Department of Physics, Stanford University, Stanford, CA 94305 (United States)

    2012-01-01

    To compute the spectrum of bubble collisions seen by an observer in an eternally-inflating multiverse, one must choose a measure over the diverging spacetime volume, including choosing an ''initial'' hypersurface below which there are no bubble nucleations. Previous calculations focused on the case where the initial hypersurface is pushed arbitrarily deep into the past. Interestingly, the observed spectrum depends on the orientation of the initial hypersurface, however one's ability observe the effect rapidly decreases with the ratio of inflationary Hubble rates inside and outside one's bubble. We investigate whether this conclusion might be avoided under more general circumstances, including placing the observer's bubble near the initial hypersurface. We find that it is not. As a point of reference, a substantial appendix reviews relevant aspects of the measure problem of eternal inflation.

  1. The charged bubble oscillator: Dynamics and thresholds

    Indian Academy of Sciences (India)

    The nonlinear, forced oscillations of a bubble in a fluid due to an external pressure field are studied theoretically. ... for the system, delineating different dynamics. Keywords. ..... (c) Power spectral density of the charged and uncharged bub-.

  2. The 2008 oil bubble. Causes and consequences

    International Nuclear Information System (INIS)

    Tokic, Damir

    2010-01-01

    We argue that 'the 2008 Oil Bubble' was directly and indirectly created by the Federal Reserve in response to deflationary risks that resurfaced after the housing bubble burst and the resulting credit crisis of 2008. Deflationary risks first appeared after the dot.com bubble burst in 2000 and after the terrorist attacks on September 11, 2001. Manipulation of the US dollar value has been one of the key emergency tools in the Fed's arsenal. During the entire period from 2000 to 2008, the US dollar has been falling, while the price of crude oil has been rising, with the culmination in July 2008. If other global central banks embrace the Fed's anti-deflationary strategies, the consequences could be dire for the global economy, potentially resulting in an ultimate gold bubble. (author)

  3. Universe out of a breathing bubble

    International Nuclear Information System (INIS)

    Guendelman, Eduardo I.; Sakai, Nobuyuki

    2008-01-01

    We consider the model of a false-vacuum bubble with a thin wall where the surface energy density is composed of two different components, 'domain-wall' type and 'dust' type, with opposite signs. We find stably oscillating solutions, which we call 'breathing bubbles'. By decay to a lower mass state, such a breathing bubble could become either (i) a child universe or ii) a bubble that 'eats up' the original universe, depending on the sign of the surface energy of the domain-wall component. We also discuss the effect of the finite-thickness corrections to the thin-wall approximation and possible origins of the energy contents of our model

  4. Electron acceleration in the bubble regime

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Oliver

    2014-02-03

    The bubble regime of laser-wakefield acceleration has been studied over the recent years as an important alternative to classical accelerators. Several models and theories have been published, in particular a theory which provides scaling laws for acceleration parameters such as energy gain and acceleration length. This thesis deals with numerical simulations within the bubble regime, their comparison to these scaling laws and data obtained from experiments, as well as some specific phenomenona. With a comparison of the scaling laws with numerical results a parameter scan was able to show a large parameter space in which simulation and theory agree. An investigation of the limits of this parameter space revealed boundaries to other regimes, especially at very high (a{sub 0} > 100) and very low laser amplitudes (a{sub 0} < 4). Comparing simulation data with data from experiments concerning laser pulse development and electron energies, it was found that experimental results can be adequately reproduced using the Virtual-Laser-Plasma-Laboratory code. In collaboration with the Institut fuer Optik und Quantenelektronik at the Friedrich-Schiller University Jena synchrotron radiation emitted from the inside of the bubble was investigated. A simulation of the movement of the electrons inside the bubble together with time dependent histograms of the emitted radiation helped to prove that the majority of radiation created during a bubble acceleration originates from the inside of the bubble. This radiation can be used to diagnose the amplitude of oscillation of the trapped electrons. During a further study it was proven that the polarisation of synchrotron radiation from a bubble contains information about the exact oscillation direction. This oscillation was successfully controlled by using either a laser pulse with a tilted pulse front or an asymmetric laser pulse. First results of ongoing studies concerning injecting electrons into an existing bubble and a scheme called

  5. Sono-chemiluminescence from a single cavitation bubble in water

    International Nuclear Information System (INIS)

    Brotchie, Adam; Shchukin, Dmitry; Moehwald, Helmuth; Schneider, Julia; Pflieger, Rachel

    2012-01-01

    In summary, this study has revealed the conditions required for a single bubble to be sono-chemically active. Evidence of radical-induced processes surrounding the bubble was only observed below the SL threshold, where the bubble was not spatially stable, and did not correlate with emission from excited molecular states inside the bubble. Moreover, this work substantiates recent progress that has been made in bridging the gap between single and multi-bubble cavitation. (authors)

  6. Effects of Gas Dynamics on Rapidly Collapsing Bubbles

    OpenAIRE

    Bauman, Spenser; Fomitchev-Zamilov, Max

    2013-01-01

    The dynamics of rapidly collapsing bubbles are of great interest due to the high degree of energy focusing that occurs withing the bubble. Molecular dynamics provides a way to model the interior of the bubble and couple the gas dynamics with the equations governing the bubble wall. While much theoretical work has been done to understand how a bubble will respond to an external force, the internal dynamics of the gas system are usually simplified greatly in such treatments. This paper shows ho...

  7. Astronaut Pedro Duque Watches A Water Bubble

    Science.gov (United States)

    2003-01-01

    Aboard the International Space Station (ISS), European Space Agency astronaut Pedro Duque of Spain watches a water bubble float between a camera and himself. The bubble shows his reflection (reversed). Duque was launched aboard a Russian Soyuz TMA-3 spacecraft from the Baikonur Cosmodrome, Kazakhstan on October 18th, along with expedition-8 crew members Michael C. Foale, Mission Commander and NASA ISS Science Officer, and Cosmonaut Alexander Y. Kaleri, Soyuz Commander and flight engineer.

  8. Acoustic waves in polydispersed bubbly liquids

    International Nuclear Information System (INIS)

    Gubaidullin, D A; Gubaidullina, D D; Fedorov, Yu V

    2014-01-01

    The propagation of acoustic waves in polydispersed mixtures of liquid with two sorts of gas bubbles each of which has its own bubble size distribution function is studied. The system of the differential equations of the perturbed motion of a mixture is presented, the dispersion relation is obtained. Equilibrium speed of sound, low-frequency and high-frequency asymptotes of the attenuation coefficient are found. Comparison of the developed theory with known experimental data is presented

  9. Acoustic waves in polydispersed bubbly liquids

    Science.gov (United States)

    Gubaidullin, D. A.; Gubaidullina, D. D.; Fedorov, Yu V.

    2014-11-01

    The propagation of acoustic waves in polydispersed mixtures of liquid with two sorts of gas bubbles each of which has its own bubble size distribution function is studied. The system of the differential equations of the perturbed motion of a mixture is presented, the dispersion relation is obtained. Equilibrium speed of sound, low-frequency and high-frequency asymptotes of the attenuation coefficient are found. Comparison of the developed theory with known experimental data is presented.

  10. Bubbles on the river of time

    International Nuclear Information System (INIS)

    Gribbin, J.

    1988-01-01

    The paper is concerned with modern cosmology, and the possibility that our Universe is just one bubble among many in some greater suprauniverse. These ideas are connected with the concept of inflation; inflation occurred shortly after the moment of creation of the Universe and just before the fireball stage that represents the big bang proper. A description is given of inflation and its use to explain the creation of the Universe from bubbles of mass-energy. (U.K.)

  11. Test ventilation with smoke, bubbles, and balloons

    International Nuclear Information System (INIS)

    Pickering, P.L.; Cucchiara, A.L.; McAtee, J.L.; Gonzales, M.

    1987-01-01

    The behavior of smoke, bubbles, and helium-filled balloons was videotaped to demonstrate the mixing of air in the plutonium chemistry laboratories, a plutonium facility. The air-distribution patterns, as indicated by each method, were compared. Helium-filled balloons proved more useful than bubbles or smoke in the visualization of airflow patterns. The replay of various segments of the videotape proved useful in evaluating the different techniques and in identifying airflow trends responsible for air mixing. 6 refs

  12. Beer tapping: dynamics of bubbles after impact

    OpenAIRE

    Mantic-Lugo, V.; Cayron, A.; Brun, P-T; Gallaire, F.

    2015-01-01

    Beer tapping is a well known prank where a bottle of beer is impacted from the top by a solid object, usually another bottle, leading to a sudden foam overflow. A description of the shock-driven bubble dynamics leading to foaming is presented based on an experimental and numerical study evoking the following physical picture. First, the solid impact produces a sudden downwards acceleration of the bottle creating a strong depression in the liquid bulk. The existing bubbles undergo a strong exp...

  13. Beer tapping: dynamics of bubbles after impact

    Science.gov (United States)

    Mantič-Lugo, V.; Cayron, A.; Brun, P.-T.; Gallaire, F.

    2015-12-01

    Beer tapping is a well known prank where a bottle of beer is impacted from the top by a solid object, usually another bottle, leading to a sudden foam overflow. A description of the shock-driven bubble dynamics leading to foaming is presented based on an experimental and numerical study evoking the following physical picture. First, the solid impact produces a sudden downwards acceleration of the bottle creating a strong depression in the liquid bulk. The existing bubbles undergo a strong expansion and a sudden contraction ending in their collapse and fragmentation into a large amount of small bubbles. Second, the bubble clouds present a large surface area to volume ratio, enhancing the CO2 diffusion from the supersaturated liquid, hence growing rapidly and depleting the CO2. The clouds of bubbles migrate upwards in the form of plumes pulling the surrounding liquid with them and eventually resulting in the foam overflow. The sudden pressure drop that triggers the bubble dynamics with a collapse and oscillations is modelled by the Rayleigh-Plesset equation. The bubble dynamics from impact to collapse occurs over a time (tb ≃ 800 μs) much larger than the acoustic time scale of the liquid bulk (tac = 2H/c ≃ 80 μs), for the experimental container of height H = 6 cm and a speed of sound around c ≃ 1500 m/s. This scale separation, together with the comparison of numerical and experimental results, suggests that the pressure drop is controlled by two parameters: the acceleration of the container and the distance from the bubble to the free surface.

  14. Numerical simulation of single bubble boiling behavior

    Directory of Open Access Journals (Sweden)

    Junjie Liu

    2017-06-01

    Full Text Available The phenomena of a single bubble boiling process are studied with numerical modeling. The mass, momentum, energy and level set equations are solved using COMSOL multi-physics software. The bubble boiling dynamics, the transient pressure field, velocity field and temperature field in time are analyzed, and reasonable results are obtained. The numeral model is validated by the empirical equation of Fritz and could be used for various applications.

  15. Bubble nonlinear dynamics and stimulated scattering process

    Science.gov (United States)

    Jie, Shi; De-Sen, Yang; Sheng-Guo, Shi; Bo, Hu; Hao-Yang, Zhang; Shi-Yong, Hu

    2016-02-01

    A complete understanding of the bubble dynamics is deemed necessary in order to achieve their full potential applications in industry and medicine. For this purpose it is first needed to expand our knowledge of a single bubble behavior under different possible conditions including the frequency and pressure variations of the sound field. In addition, stimulated scattering of sound on a bubble is a special effect in sound field, and its characteristics are associated with bubble oscillation mode. A bubble in liquid can be considered as a representative example of nonlinear dynamical system theory with its resonance, and its dynamics characteristics can be described by the Keller-Miksis equation. The nonlinear dynamics of an acoustically excited gas bubble in water is investigated by using theoretical and numerical analysis methods. Our results show its strongly nonlinear behavior with respect to the pressure amplitude and excitation frequency as the control parameters, and give an intuitive insight into stimulated sound scattering on a bubble. It is seen that the stimulated sound scattering is different from common dynamical behaviors, such as bifurcation and chaos, which is the result of the nonlinear resonance of a bubble under the excitation of a high amplitude acoustic sound wave essentially. The numerical analysis results show that the threshold of stimulated sound scattering is smaller than those of bifurcation and chaos in the common condition. Project supported by the Program for Changjiang Scholars and Innovative Research Team in University, China (Grant No. IRT1228) and the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 11204050 and 11204049).

  16. A simple circuit to deliver bubbling CPAP.

    Science.gov (United States)

    Kaur, Charanjit; Sema, Akatoli; Beri, Rajbir S; Puliyel, Jacob M

    2008-04-01

    Nasal continuous positive airway pressure (CPAP), especially bubbling CPAP, is known to reduce the need for more invasive ventilation. We here describe a circuit that can deliver bubbling CPAP in resource poor settings. We describe how the oxygen concentration can be altered from 98% to 21% oxygen using this system. Addition of a humidifier in the circuit has the effect of reducing the oxygen concentration by 1 to 5%. The cost of putting together the system is approximately Rs 5000.

  17. Bubble chamber: Omega production and decay

    CERN Document Server

    1973-01-01

    This image is taken from one of CERN's bubble chambers and shows the decay of a positive kaon in flight. The decay products of this kaon can be seen spiraling in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that has been heated to boiling point.

  18. LIQUID-LIQUID EXTRACTION COLUMNS

    Science.gov (United States)

    Thornton, J.D.

    1957-12-31

    This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

  19. Bubble parameters analysis of gas-liquid two-phase sparse bubbly flow based on image method

    International Nuclear Information System (INIS)

    Zhou Yunlong; Zhou Hongjuan; Song Lianzhuang; Liu Qian

    2012-01-01

    The sparse rising bubbles of gas-liquid two-phase flow in vertical pipe were measured and studied based on image method. The bubble images were acquired by high-speed video camera systems, the characteristic parameters of bubbles were extracted by using image processing techniques. Then velocity variation of rising bubbles were drawn. Area and centroid variation of single bubble were also drawn. And then parameters and movement law of bubbles were analyzed and studied. The test results showed that parameters of bubbles had been analyzed well by using image method. (authors)

  20. Column-Oriented Database Systems (Tutorial)

    OpenAIRE

    Abadi, D.; Boncz, Peter; Harizopoulos, S.

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subset of a table’s columns becomes faster, at the potential expense of excessive disk-head s...

  1. Gas-liquid mass transfer coefficient of methane in bubble column reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaewon; Ha, Kyoung-Su; Lee, Jinwon; Kim, Choongik [Sogang University, Seoul (Korea, Republic of); Yasin, Muhammad; Park, Shinyoung; Chang, In Seop [Gwangju Institute of Science and Technology (GIST), Gwangju (Korea, Republic of); Lee, Eun Yeol [Kyung Hee University, Yongin (Korea, Republic of)

    2015-06-15

    Biological conversion of methane gas has been attracting considerable recent interest. However, methanotropic bioreactor is limited by low solubility of methane gas in aqueous solution. Although a large mass transfer coefficient of methane in water could possibly overcome this limitation, no dissolved methane probe in aqueous environment is commercially available. We have developed a reactor enabling the measurement of aqueous phase methane concentration and mass transfer coefficient (k{sub L}a). The feasibility of the new reactor was demonstrated by measuring k{sub L}a values as a function of spinning rate of impeller and flow rate of methane gas. Especially, at spinning rate of 300 rpm and flow rate of 3.0 L/min, a large k{sub L}a value of 102.9 h{sup -1} was obtained.

  2. Wall heat transfer coefficient in a molten salt bubble column: testing the experimental setup

    CSIR Research Space (South Africa)

    Skosana, PJ

    2014-10-01

    Full Text Available reactors that are highly exothermic or endothermic. This paper presents the design and operation of experimental setup used for measurement of the heat transfer coefficient in molten salt media. The experimental setup was operated with tap water, heat...

  3. Degradation and depolymerization of plastic waste by local bacterial isolates and bubble column reactor

    Science.gov (United States)

    Hussein, Amal A.; Alzuhairi, Mohammed; Aljanabi, Noor H.

    2018-05-01

    Accumulation of plastics, especially Polyethylene terephthalate (PET), is an ever increasing ecological threat due to its excessive usage in everyday human life. Nowadays, there are many methods to get rid of plastic wastes including burning, recycling and burying. However, these methods are not very active since their long period, anaerobic conditions that increase the rate of toxic materials released into the environment. This work aims to study the biological degradation of PET microorganism isolated from soil sample. Thirty eight (38) bacterial isolates were isolated from ten soil and plastic waste sample collected from four different waste disposal sites in Baghdad city during different periods between December 2016 and March 2017. Isolation was performed using enrichment culture method (flasks method) by culturing the soil samples in flasks with MSM medium where there is no carbon source only PET. Results showed that Al-Za'farania sample gave a higher number of isolates (13 isolates), while other samples gave less number of isolates. Screening was performed depending on their ability to grow in liquid MSM which contains PET powder and pieces and change the color of the PET-emulsified liquid medium as well as their ability to form the clear zone on PET-MSM agar. The results showed that NH-D-1 isolate has the higher ability to degrade DPET and PET pieces. According to morphological, biochemical characterization and Vitek-2 technique, the most active isolate was identified as Acinetobacter baumannii.

  4. Gas-liquid mass transfer coefficient of methane in bubble column reactor

    International Nuclear Information System (INIS)

    Lee, Jaewon; Ha, Kyoung-Su; Lee, Jinwon; Kim, Choongik; Yasin, Muhammad; Park, Shinyoung; Chang, In Seop; Lee, Eun Yeol

    2015-01-01

    Biological conversion of methane gas has been attracting considerable recent interest. However, methanotropic bioreactor is limited by low solubility of methane gas in aqueous solution. Although a large mass transfer coefficient of methane in water could possibly overcome this limitation, no dissolved methane probe in aqueous environment is commercially available. We have developed a reactor enabling the measurement of aqueous phase methane concentration and mass transfer coefficient (k L a). The feasibility of the new reactor was demonstrated by measuring k L a values as a function of spinning rate of impeller and flow rate of methane gas. Especially, at spinning rate of 300 rpm and flow rate of 3.0 L/min, a large k L a value of 102.9 h -1 was obtained

  5. Measurement of gas-liquid two-phase flow in bubble columns using ensemble correlation PIV

    NARCIS (Netherlands)

    Delnoij, E.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria; Westerweel, J.

    2000-01-01

    This paper highlights the development of a new ensemble correlation, multiphase flow PIV technique. The particular approach discussed in this paper is a straightforward extension of single-phase PIV and one of the major advantages of the technique is that it employs a single CCD camera. This

  6. Modeling and Control Perspectives of Two-Phase Fluid Systems - with Applications to Bubble Columns

    NARCIS (Netherlands)

    Djordjevic, S.

    2011-01-01

    The recent progress in the chemical industry is now forcing engineers and physicists to get to deal with control-oriented modeling of material properties on microscopic scale inside reactors in order to build more efficient chemical plants. The control-oriented modeling provides a new way of

  7. Intensely oscillating cavitation bubble in microfluidics

    International Nuclear Information System (INIS)

    Siew-Wan, Ohl; Tandiono; Klaseboer, Evert; Dave, Ow; Choo, Andre; Claus-Dieter, Ohl

    2015-01-01

    This study reports the technical breakthrough in generating intense ultrasonic cavitation in the confinement of a microfluidics channel [1], and applications that has been developed on this platform for the past few years [2,3,4,5]. Our system consists of circular disc transducers (10-20 mm in diameter), the microfluidics channels on PDMS (polydimethylsiloxane), and a driving circuitry. The cavitation bubbles are created at the gas- water interface due to strong capillary waves which are generated when the system is driven at its natural frequency (around 100 kHz) [1]. These bubbles oscillate and collapse within the channel. The bubbles are useful for sonochemistry and the generation of sonoluminescence [2]. When we add bacteria (Escherichia coli), and yeast cells (Pichia pastoris) into the microfluidics channels, the oscillating and collapsing bubbles stretch and lyse these cells [3]. Furthermore, the system is effective (DNA of the harvested intracellular content remains largely intact), and efficient (yield reaches saturation in less than 1 second). In another application, human red blood cells are added to a microchamber. Cell stretching and rapture are observed when a laser generated cavitation bubble expands and collapses next to the cell [4]. A numerical model of a liquid pocket surrounded by a membrane with surface tension which was placed next to an oscillating bubble was developed using the Boundary Element Method. The simulation results showed that the stretching of the liquid pocket occurs only when the surface tension is within a certain range. (paper)

  8. Gas transfer in a bubbly wake flow

    Science.gov (United States)

    Karn, A.; Gulliver, J. S.; Monson, G. M.; Ellis, C.; Arndt, R. E. A.; Hong, J.

    2016-05-01

    The present work reports simultaneous bubble size and gas transfer measurements in a bubbly wake flow of a hydrofoil, designed to be similar to a hydroturbine blade. Bubble size was measured by a shadow imaging technique and found to have a Sauter mean diameter of 0.9 mm for a reference case. A lower gas flow rate, greater liquid velocities, and a larger angle of attack all resulted in an increased number of small size bubbles and a reduced weighted mean bubble size. Bubble-water gas transfer is measured by the disturbed equilibrium technique. The gas transfer model of Azbel (1981) is utilized to characterize the liquid film coefficient for gas transfer, with one scaling coefficient to reflect the fact that characteristic turbulent velocity is replaced by cross-sectional mean velocity. The coefficient was found to stay constant at a particular hydrofoil configuration while it varied within a narrow range of 0.52-0.60 for different gas/water flow conditions.

  9. Effects of Solution Chemistry on Nano-Bubbles Transport in Saturated Porous Media

    Science.gov (United States)

    Hamamoto, S.; Takemura, T.; Suzuki, K.; Nihei, N.; Nishimura, T.

    2017-12-01

    Nano-bubbles (NBs) have a considerable potential for the remediation of soil and groundwater contaminated by organic compounds, especially when used in conjunction with bioremediation technologies. Understanding the transport mechanisms of NBs in soils is essential to optimize NB-based remediation techniques. In this study, one-dimensional column transport experiments using glass beads with 0.1 mm size were conducted, where NBs created by oxygen gas at different pH and ionic strength were injected to the column at the constant flow rate. The NBs concentration in the effluent was quantified using a resonant mass measurement technique. Effects of solution chemistry of the NBs water on NB transport in the porous media were investigated. The results showed that attachment of NBs was enhanced under higher ionic strength and lower pH conditions, caused by the reduced repulsive force between NBs and glass beads. In addition, bubble size distributions in the effluents showed that relatively larger NBs were retained in the column. This trend was more significant at lower pH condition.

  10. Bubbling AdS3

    International Nuclear Information System (INIS)

    Martelli, Dario; Morales, Jose Francisco

    2005-01-01

    In the light of the recent Lin, Lunin, Maldacena (LLM) results, we investigate 1/2-BPS geometries in minimal (and next to minimal) supergravity in D = 6 dimensions. In the case of minimal supergravity, solutions are given by fibrations of a two-torus T 2 specified by two harmonic functions. For a rectangular torus the two functions are related by a non-linear equation with rare solutions: AdS 3 x S 3 , the pp-wave and the multi-center string. 'Bubbling', i.e. superpositions of droplets, is accommodated by allowing the complex structure of the T 2 to vary over the base. The analysis is repeated in the presence of a tensor multiplet and similar conclusions are reached, with generic solutions describing D1D5 (or their dual fundamental string-momentum) systems. In this framework, the profile of the dual fundamental string-momentum system is identified with the boundaries of the droplets in a two-dimensional plane. (author)

  11. Radiotracer Imaging of Sediment Columns

    Science.gov (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  12. Runaway and thermally safe operation of a nitric acid oxidation in a semi-batch reactor

    NARCIS (Netherlands)

    van Woezik, B.A.A.

    2000-01-01

    A number of serious accidents has occurred due to a runaway reaction of a heterogeneous liquid-liquid reaction whereby a secondary side reaction was triggered. A basic lack of proper knowledge of all the phenomena, occurring in such a system, is one of the prime causes that may lead to overheating

  13. Mass Transfer and Kinetics Study of Heterogeneous Semi-Batch Precipitation of Magnesium Carbonate

    DEFF Research Database (Denmark)

    Han, B.; Qu, H. Y.; Niemi, H.

    2014-01-01

    Precipitation kinetics and mass transfer of magnesium carbonate (MgCO3) hydrates from a reaction of magnesium hydroxide (Mg(OH)(2)) and CO2 were analyzed. The effect of CO2 flow rate and mixing intensity on precipitation was investigated under ambient temperature and atmospheric pressure. Raman...... on the dissolution of Mg(OH)(2). In the researched system, the main driver of the precipitation kinetics was the mass transfer of CO2. Nesquehonite (MgCO3 center dot 3H(2)O), as needle-like crystals, was precipitated as the main product. Raman spectroscopy can serve as a potential tool to monitor the carbonation...

  14. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.

    2017-12-01

    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  15. Development of three-dimensional individual bubble-velocity measurement method by bubble tracking

    International Nuclear Information System (INIS)

    Kanai, Taizo; Furuya, Masahiro; Arai, Takahiro; Shirakawa, Kenetsu; Nishi, Yoshihisa

    2012-01-01

    A gas-liquid two-phase flow in a large diameter pipe exhibits a three-dimensional flow structure. Wire-Mesh Sensor (WMS) consists of a pair of parallel wire layers located at the cross section of a pipe. Both the parallel wires cross at 90o with a small gap and each intersection acts as an electrode. The WMS allows the measurement of the instantaneous two-dimensional void-fraction distribution over the cross-section of a pipe, based on the difference between the local instantaneous conductivity of the two-phase flow. Furthermore, the WMS can acquire a phasic-velocity on the basis of the time lag of void signals between two sets of WMS. Previously, the acquired phasic velocity was one-dimensional with time-averaged distributions. The authors propose a method to estimate the three-dimensional bubble-velocity individually WMS data. The bubble velocity is determined by the tracing method. In this tracing method, each bubble is separated from WMS signal, volume and center coordinates of the bubble is acquired. Two bubbles with near volume at two WMS are considered as the same bubble and bubble velocity is estimated from the displacement of the center coordinates of the two bubbles. The validity of this method is verified by a swirl flow. The proposed method can successfully visualize a swirl flow structure and the results of this method agree with the results of cross-correlation analysis. (author)

  16. Formation and evolution of bubbly screens in confined oscillating bubbly liquids

    Science.gov (United States)

    Shklyaev, Sergey; Straube, Arthur V.

    2010-01-01

    We consider the dynamics of dilute monodisperse bubbly liquid confined by two plane solid walls and subject to small-amplitude high-frequency oscillations normal to the walls. The initial state corresponds to the uniform distribution of bubbles and motionless liquid. The period of external driving is assumed much smaller than typical relaxation times for a single bubble but larger than the period of volume eigenoscillations. The time-averaged description accounting for the two-way coupling between the liquid and the bubbles is applied. We show that the model predicts accumulation of bubbles in thin sheets parallel to the walls. These singular structures, which are formally characterized by infinitely thin width and infinitely high concentration, are referred to as bubbly screens. The formation of a bubbly screen is described analytically in terms of a self-similar solution, which is in agreement with numerical simulations. We study the evolution of bubbly screens and detect a one-dimensional stationary state, which is shown to be unconditionally unstable.

  17. Financial Bubbles, Real Estate Bubbles, Derivative Bubbles, and the Financial and Economic Crisis

    Science.gov (United States)

    Sornette, Didier; Woodard, Ryan

    The financial crisis of 2008, which started with an initially well-defined epicenter focused on mortgage backed securities (MBS), has been cascading into a global economic recession, whose increasing severity and uncertain duration has led and is continuing to lead to massive losses and damage for billions of people. Heavy central bank interventions and government spending programs have been launched worldwide and especially in the USA and Europe, with the hope to unfreeze credit and bolster consumption. Here, we present evidence and articulate a general framework that allows one to diagnose the fundamental cause of the unfolding financial and economic crisis: the accumulation of several bubbles and their interplay and mutual reinforcement have led to an illusion of a "perpetual money machine" allowing financial institutions to extract wealth from an unsustainable artificial process. Taking stock of this diagnostic, we conclude that many of the interventions to address the so-called liquidity crisis and to encourage more consumption are ill-advised and even dangerous, given that precautionary reserves were not accumulated in the "good times" but that huge liabilities were. The most "interesting" present times constitute unique opportunities but also great challenges, for which we offer a few recommendations.

  18. Effects of additional inertia force on bubble breakup

    International Nuclear Information System (INIS)

    Pan Liangming; Zhang Wenzhi; Chen Deqi; Xu Jianhui; Xu Jianjun; Huang Yanping

    2011-01-01

    Through VOF two-phase flow model, the single bubble deformation and breakup in a vertical narrow channel is numerically investigated in the study based on the force balance at the process of bubble breakup. The effect of surface tension force, the additional inertia force and bubble initial shape on bubble breakup are analyzed according to the velocity variation at the break-up point and the minimum necking size when the bubble is breaking up. It is found that the surface tension force, the additional inertia force and the bubble initial shape have significant effects on the bubble breakup through the fluid injection toward to the bubble, which finally induces the onset of bubble breakup. (authors)

  19. Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns?

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Dennis, Gary R; Shalliker, R Andrew

    2015-08-19

    Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. Copyright © 2015. Published by Elsevier B.V.

  20. Non-intuitive bubble effects in reactor and containment technology

    International Nuclear Information System (INIS)

    Moody, F.J.

    1991-01-01

    Most people know a lot about bubbles, including how they rise in liquids and the way they appear when the cap is removed from a bottle of carbonated beverage. A lot of bubble knowledge is obtained from bubbling air through water in aquariums to keep the fish alive and happy, or watching scuba divers feed the sharks in large glass tanks at the local zoo. But innocent bubbles can be sources of structural loadings and sometimes destructive fluid behavior. In fact, there are many non-intuitive effects associated with bubbles which have been discovered by experiments and analyses. It has been necessary to design various reactor and containment components in the nuclear energy industry to accommodate the fact that bubbles can expand like compressed springs, or oscillate, or collapse abruptly, and create structural loads. This paper describes several important phenomena associated with bubble action in nuclear reactor and containment systems and the associated loads exerted. An awareness of these effects can help to avoid unwelcome surprises in general thermal-hydraulic applications when a system is disturbed by bubble behavior. Major topics discussed include expanding and collapsing submerged bubbles, steam chugging and ringout, bubble shattering, surprising hot bubble action in a saturated pool, bubble effects on fluid-structure-interaction, waterhammer from collapsing bubble in pipes, and vapor bubble effects on sound speed in saturated mixtures

  1. Effect of microstructure on helium bubble growth in irradiated nickel

    International Nuclear Information System (INIS)

    Sattler, M.L.

    1986-01-01

    Thin nickel films were irradiated with 80 keV helium ions at varying doses and varying temperatures in order to obtain a variety of final microstructures. The growth of bubbles was examined during in-situ irradiations at 950 0 C where migration and coalescence events were observed for bubbles as large as 60 nm. Further direct observations of bubble growth were made during annealing of the irradiated specimens. For sample with no visible bubbles before annealing, the heating to 0.51 T/sub M/ produced bubbles that increased in diameter with annealing time to the power n. For bubbles in the grain interior, n ∼ 1, and on the grain boundaries, n ∼ 0.6. Since no migration and coalescence or ripening theories predict this behavior, a theory described by transient diffusion to spherical sinks was developed to discuss the behavior. This theory predicts that n = 1 for bubbles growing in the grain interior and n = 0.5 for bubbles on the grain boundary. In other annealing of irradiated samples containing large bubble populations, the growth of large bubbles and shrinking of small bubbles was observed at a temperature equal to 0.54 T/sub M/. The theory of Ostwald ripening properly described this type of bubble growth. Mass spectrometer measurements of He content in the irradiated specimens showed a greater He retention in the Ni films that contained a significant bubble population than those with no visible bubbles

  2. Convective mass transfer around a dissolving bubble

    Science.gov (United States)

    Duplat, Jerome; Grandemange, Mathieu; Poulain, Cedric

    2017-11-01

    Heat or mass transfer around an evaporating drop or condensing vapor bubble is a complex issue due to the interplay between the substrate properties, diffusion- and convection-driven mass transfer, and Marangoni effects, to mention but a few. In order to disentangle these mechanisms, we focus here mainly on the convective mass transfer contribution in an isothermal mass transfer problem. For this, we study the case of a millimetric carbon dioxide bubble which is suspended under a substrate and dissolved into pure liquid water. The high solubility of CO2 in water makes the liquid denser and promotes a buoyant-driven flow at a high (solutal) Rayleigh number (Ra˜104 ). The alteration of p H allows the concentration field in the liquid to be imaged by laser fluorescence enabling us to measure both the global mass flux (bubble volume, contact angle) and local mass flux around the bubble along time. After a short period of mass diffusion, where the boundary layer thickens like the square root of time, convection starts and the CO2 is carried by a plume falling at constant velocity. The boundary layer thickness then reaches a plateau which depends on the bubble cross section. Meanwhile the plume velocity scales like (dV /d t )1 /2 with V being the volume of the bubble. As for the rate of volume loss, we recover a constant mass flux in the diffusion-driven regime followed by a decrease in the volume V like V2 /3 after convection has started. We present a model which agrees well with the bubble dynamics and discuss our results in the context of droplet evaporation, as well as high Rayleigh convection.

  3. A grid-independent EMMS/bubbling drag model for bubbling and turbulent fluidization

    DEFF Research Database (Denmark)

    Luo, Hao; Lu, Bona; Zhang, Jingyuan

    2017-01-01

    The EMMS/bubbling drag model takes the effects of meso-scale structures (i.e. bubbles) into modeling of drag coefficient and thus improves coarse-grid simulation of bubbling and turbulent fluidized beds. However, its dependence on grid size has not been fully investigated. In this article, we adopt...... a two-step scheme to extend the EMMS/bubbling model to the sub-grid level. Thus the heterogeneity index, HD, which accounts for the hydrodynamic disparity between homogeneous and heterogeneous fluidization, can be correlated as a function of both local voidage and slip velocity. Simulations over...... a periodic domain show the new drag model is less sensitive to grid size because of the additional dependence on local slip velocity. When applying the new drag model to simulations of realistic bubbling and turbulent fluidized beds, we find grid-independent results are easier to obtain for high...

  4. NOx retention in scrubbing column

    International Nuclear Information System (INIS)

    Nakazone, A.K.; Costa, R.E.; Lobao, A.S.T.; Matsuda, H.T.; Araujo, B.F.

    1988-07-01

    During the UO 2 dissolution in nitric acid, some different species of NO x are released. The off gas can either be refluxed to the dissolver or be released and retained on special columns. The final composition of the solution is the main parameter to take in account. A process for nitrous gases retention using scubber columns containing H 2 O or diluted HNO 3 is presented. Chemiluminescence measurement was employed to NO x evalution before and after scrubbing. Gas flow, temperature, residence time are the main parameters considered in this paper. For the dissolution of 100g UO 2 in 8M nitric acid, a 6NL/h O 2 flow was the best condition for the NO/NO 2 oxidation with maximum adsorption in the scrubber columns. (author) [pt

  5. Herds of methane chambers grazing bubbles

    Science.gov (United States)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  6. Creeping motion of long bubbles and drops in capillary tubes

    DEFF Research Database (Denmark)

    Westborg, Henrik; Hassager, Ole

    1989-01-01

    The flow of inviscid bubbles and viscous drops in capillary tubes has been simulated by a Galerkin finite element method with surface tension included at the bubble/liquid interface. The results show good agreement with published experimental results. At low capillary numbers the front and the rear...... of the bubble are nearly spherical. As the capillary number increases the thickness of the wetting film between the tube wall and the bubble increases, and the bubble assumes a more slender shape with a characteristic bump at the rear. Recirculations are found in front and behind the bubble, which disappear...

  7. Interferometric measurement of film thickness during bubble blowing

    Science.gov (United States)

    Wang, Z.; Mandracchia, B.; Ferraro, V.; Tammaro, D.; Di Maio, E.; Maffettone, P. L.; Ferraro, P.

    2017-06-01

    In this paper, we propose digital holography in transmission configuration as an effective method to measure the time-dependent thickness of polymeric films during bubble blowing. We designed a complete set of experiments to measure bubble thickness, including the evaluation of the refractive index of the polymer solution. We report the measurement of thickness distribution along the film during the bubble formation process until the bubble`s rupture. Based on those data, the variation range and variation trend of bubble film thickness are clearly measured during the process of expansion to fracture is indicated.

  8. Argonne Bubble Experiment Thermal Model Development III

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-11

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development” and “Argonne Bubble Experiment Thermal Model Development II”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at beam power levels between 6 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was recorded. The previous report2 described the Monte-Carlo N-Particle (MCNP) calculations and Computational Fluid Dynamics (CFD) analysis performed on the as-built solution vessel geometry. The CFD simulations in the current analysis were performed using Ansys Fluent, Ver. 17.2. The same power profiles determined from MCNP calculations in earlier work were used for the 12 and 15 kW simulations. The primary goal of the current work is to calculate the temperature profiles for the 12 and 15 kW cases using reasonable estimates for the gas generation rate, based on images of the bubbles recorded during the irradiations. Temperature profiles resulting from the CFD calculations are compared to experimental measurements.

  9. Drop impact entrapment of bubble rings

    KAUST Repository

    Thoraval, M.-J.

    2013-04-29

    We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 -s after the first contact, requiring imaging at 1 million f.p.s. For a water drop impacting on a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Reynolds number Re above -12 000, up to 10 partial bubble rings have been observed at the base of the ejecta, starting when the contact is -20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into micro-bubbles. The different refractive index in the pool liquid reveals the destabilization of the vortices and the formation of streamwise vortices and intricate vortex tangles. Fine-scale axisymmetry is thereby destroyed. We show also that the shape of the drop has a strong influence on these dynamics. 2013 Cambridge University Press.

  10. Bubble growth in a narrow horizontal space

    Energy Technology Data Exchange (ETDEWEB)

    Stutz, Benoit; Goulet, Remi [CETHIL, UMR5008, CNRS, INSA-Lyon, Universite Lyon1 (France); Passos, Julio Cesar [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. LABSOLAR

    2009-07-01

    The purpose of this work is to develop an axis-symmetric two-phase flow model describing the growth of a single bubble squeezed between a horizontal heated upward-facing disc and an insulating surface placed parallel to the heated surface. Heat transfers at the liquid-vapour interfaces are predicted by the kinetic limit of vaporisation. The depths of the liquid films deposed on the surfaces (heated surface and confinement space) are determined using the Moriyama and Inoue correlation (1996). Transient heat transfers within the heated wall are taken into account. The model is applied to pentane bubble growth. The influence of the gap size, the initial temperature of the system, the thermal effusivity of the heated wall and the kinetic limit of vaporisation are studied. The results show that the expansion of the bubbles strongly depends on the gap size and can be affected by the effusivity of the material. Mechanical inertia effects are mainly dominant at the beginning of the bubble expansion. Pressure drop induced by viscous effects have to be taken into account for high capillary numbers. Heat transfers at the meniscus are negligible except at the early stages of the bubble growth. (author)

  11. Bubble growth in a narrow horizontal space

    International Nuclear Information System (INIS)

    Stutz, Benoit; Goulet, Remi; Passos, Julio Cesar

    2009-01-01

    The purpose of this work is to develop an axis-symmetric two-phase flow model describing the growth of a single bubble squeezed between a horizontal heated upward-facing disc and an insulating surface placed parallel to the heated surface. Heat transfers at the liquid-vapour interfaces are predicted by the kinetic limit of vaporisation. The depths of the liquid films deposed on the surfaces (heated surface and confinement space) are determined using the Moriyama and Inoue correlation (1996). Transient heat transfers within the heated wall are taken into account. The model is applied to pentane bubble growth. The influence of the gap size, the initial temperature of the system, the thermal effusivity of the heated wall and the kinetic limit of vaporisation are studied. The results show that the expansion of the bubbles strongly depends on the gap size and can be affected by the effusivity of the material. Mechanical inertia effects are mainly dominant at the beginning of the bubble expansion. Pressure drop induced by viscous effects have to be taken into account for high capillary numbers. Heat transfers at the meniscus are negligible except at the early stages of the bubble growth. (author)

  12. Turbulent shear control with oscillatory bubble injection

    International Nuclear Information System (INIS)

    Park, Hyun Jin; Oishi, Yoshihiko; Tasaka, Yuji; Murai, Yuichi; Takeda, Yasushi

    2009-01-01

    It is known that injecting bubbles into shear flow can reduce the frictional drag. This method has advantages in comparison to others in simplicity of installation and also in environment. The amount of drag reduction by bubbles depends on the void fraction provided in the boundary layer. It means, however, that certain power must be consumed to generate bubbles in water, worsening the total power-saving performance. We propose oscillatory bubble injection technique to improve the performance in this study. In order to prove this idea of new type of drag reduction, velocity vector field and shear stress profile in a horizontal channel flow are measured by ultrasonic velocity profiler (UVP) and shear stress transducer, respectively. We measure the gas-liquid interface from the UVP signal, as well. This compound measurement with different principles leads to deeper understanding of bubble-originated drag reduction phenomena, in particular for unsteady process of boundary layer alternation. At these experiments, the results have demonstrated that the intermittency promotes the drag reduction more than normal continuous injection for the same void fraction supplied.

  13. Modelling of boiling bubbly flows using a polydisperse approach

    International Nuclear Information System (INIS)

    Zaepffel, D.

    2011-01-01

    The objective of this work was to improve the modelling of boiling bubbly flows.We focused on the modelling of the polydisperse aspect of a bubble population, i.e. the fact that bubbles have different sizes and different velocities. The multi-size aspect of a bubble population can originate from various mechanisms. For the bubbly flows we are interested in, bubble coalescence, bubble break-up, phase change kinematics and/or gas compressibility inside the bubbles can be mentioned. Since, bubble velocity depends on bubble size, the bubble size spectrum also leads to a bubble velocity spectrum. An averaged model especially dedicated to dispersed flows is introduced in this thesis. Closure of averaged interphase transfer terms are written in a polydisperse framework, i.e. using a distribution function of the bubble sizes and velocities. A quadratic law and a cubic law are here proposed for the modelling of the size distribution function, whose evolution in space and time is then obtained with the use of the moment method. Our averaged model has been implemented in the NEPTUNE-CFD computation code in order to simulate the DEBORA experiment. The ability of our model to deal with sub-cooled boiling flows has therefore been evaluated. (author) [fr

  14. The bubble method of water purification

    Science.gov (United States)

    Smirnov, B. M.; Babaeva, N. Yu.; Naidis, G. V.; Panov, V. A.; Saveliev, A. S.; Son, E. E.; Tereshonok, D. V.

    2018-02-01

    The processes of water purification from admixture molecules are analyzed. The purification rate is limited due to a low diffusion coefficient of the admixture molecules in water. At non-small concentrations of the admixture molecules, the water purication can proceed through association of molecules in condensed nanoparticles which fall on the bottom of the water volume. The rate of association may be increased in an external electric field, but in reality this cannot change significantly the rate of the purification process. The bubble method of water purification is considered, where air bubbles formed at the bottom of the water volume, transfer admixture molecules to the interface. This method allows one to clean small water volumes fast. This mechanism of water purification is realized experimentally and exhibits the promises of the bubble purification method.

  15. Bubbles, sparks, and the postwar laboratory

    International Nuclear Information System (INIS)

    Galison, P.

    1989-01-01

    The development and use of bubble chambers and spark chambers in the 1950s form the main thrust of this article, the bubble chamber as an example of ''image-producing'' instruments and the spark chamber as a ''logic'' device. Work on a cloud chamber by Glaser led to the development of the bubble chamber detector using liquid hydrogen, which was later linked to a computer for accurate automatic track analysis. It made possible demonstrations of the existence of a particle or interaction. Spark chambers were easier to build and so soon became common, various types being developed across the world. The development of spark chambers originated in the need for timing devices for the Manhattan Project, but work on their design occurred in a number of units worldwide. (UK)

  16. Bubble and Drop Nonlinear Dynamics experiment

    Science.gov (United States)

    2003-01-01

    The Bubble and Drop Nonlinear Dynamics (BDND) experiment was designed to improve understanding of how the shape and behavior of bubbles respond to ultrasound pressure. By understanding this behavior, it may be possible to counteract complications bubbles cause during materials processing on the ground. This 12-second sequence came from video downlinked from STS-94, July 5 1997, MET:3/19:15 (approximate). The BDND guest investigator was Gary Leal of the University of California, Santa Barbara. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced fluid dynamics experiments will be a part of investigations plarned for the International Space Station. (189KB JPEG, 1293 x 1460 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300163.html.

  17. ON THE ANALYSIS OF BUBBLE CHAMBER TRACKS

    International Nuclear Information System (INIS)

    Bradner, H.; Solmitz, F.

    1958-01-01

    Since its invention by Glaser in 1953, the bubble chamber has become a most valuable tool in high-energy physics. It combines a number of advantages of various older methods of particle detection: it offers high spatial resolution, rapid accumulation of data, some time resolution, and some choice of the nucleus whose interaction one wants to study (bubble chambers have been made to operate with a large number of different liquids, including H 2 , D 2 , He, Xe, and several hydrocarbons). In order to exploit the advantages of spatial resolution and rapid data accumulation, high-speed high-precision analysis procedures must be developed. In this article they discuss some of the problems posed by such analysis. The discussion is based largely on experience gained in performing hydrogen bubble chamber experiments with the University of California's Bevatron (6-Bev proton synchrotron)

  18. Bubbles, shocks and elementary technical trading strategies

    Science.gov (United States)

    Fry, John

    2014-01-01

    In this paper we provide a unifying framework for a set of seemingly disparate models for bubbles, shocks and elementary technical trading strategies in financial markets. Markets operate by balancing intrinsic levels of risk and return. This seemingly simple observation is commonly over-looked by academics and practitioners alike. Our model shares its origins in statistical physics with others. However, under our approach, changes in market regime can be explicitly shown to represent a phase transition from random to deterministic behaviour in prices. This structure leads to an improved physical and econometric model. We develop models for bubbles, shocks and elementary technical trading strategies. The list of empirical applications is both interesting and topical and includes real-estate bubbles and the on-going Eurozone crisis. We close by comparing the results of our model with purely qualitative findings from the finance literature.

  19. Experimental investigation of bubble plume structure instability

    Energy Technology Data Exchange (ETDEWEB)

    Marco Simiano; Robert Zboray; Francois de Cachard [Thermal-Hydraulics Laboratory, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Djamel Lakehal; George Yadigaroglu [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH-Zentrum/CLT, 8092 Zurich (Switzerland)

    2005-07-01

    Full text of publication follows: The hydrodynamic properties of a 3D bubble plume in a large water pool are investigated experimentally. Bubble plumes are present in various industrial processes, including chemical plants, stirred reactors, and nuclear power plants, e.g. in BWR suppression pools. In these applications, the main issue is to predict the currents induced by the bubbles in the liquid phase, and to determine the consequent mixing. Bubble plumes, especially large and unconfined ones, present strong 3D effects and a superposition of different characteristic length scales. Thus, they represent relevant test cases for assessment and verification of 3D models in thermal-hydraulic codes. Bubble plumes are often unsteady, with fluctuations in size and shape of the bubble swarm, and global movements of the plume. In this case, local time-averaged data are not sufficient to characterize the flow. Additional information regarding changes in plume shape and position is required. The effect of scale on the 3D flow structure and stability being complex, there was a need to conduct studies in a fairly large facility, closer to industrial applications. Air bubble plumes, up to 30 cm in base diameter and 2 m in height were extensively studied in a 2 m diameter water pool. Homogeneously sized bubbles were obtained using a particular injector. The main hydrodynamic parameters. i.e., gas and liquid velocities, void fraction, bubble shape and size, plume shape and position, were determined experimentally. Photographic and image processing techniques were used to characterize the bubble shape, and double-tip optical probes to measure bubble size and void fraction. Electromagnetic probes measured the recirculation velocity in the pool. Simultaneous two-phase flow particle image velocimetry (STPFPIV) in a vertical plane containing the vessel axis provided instantaneous velocity fields for both phases and therefore the relative velocity field. Video recording using two CCD

  20. Rational speculative bubbles: A critical view

    Directory of Open Access Journals (Sweden)

    Radonjić Ognjen

    2007-01-01

    Full Text Available According to the theory of rational bubbles, the bubble is present whenever asset prices progressively diverge from their fundamental value, which occurs because agents expect that asset prices will continue to grow exponentially (self-fulfilling prophecies far in the future and consistently, which promises the realization of ever larger capital gains. In our opinion, the basic shortcoming of this theory refers to the assumption that all market agents are perfectly informed and rational and, accordingly, form homogeneous expectations. The model does not explain decision-making processes or expectation formation, nor does it detect potential psychological and institutional factors that might significantly influence decision making processes and market participants’ reactions to news. Since assumptions of the model critically determine its validity, we conclude that comprehensiveness of the rational bubble model is, to put it mildly, limited.

  1. Toward a Metatheory of Economic Bubbles

    DEFF Research Database (Denmark)

    Dholakia, Nikhilesh; Turcan, Romeo V.

    Dholakia and Turcan present their interdisciplinary metatheory of bubbles with short case studies of minor and major bubbles. They comprehensively identify and exemplify constructs of the theory, set its temporal and contextual boundaries, and examine the underlying economic, psychological......, and social dynamics assumptions, explaining how these elements are related. By doing so, they provide a partial window into the precarious nature of contemporary finance-driven capitalism and suggest some possible ways of overcoming the wrenching ups and downs of the prevalent system. The case studies...... and original research in Toward a Metatheory of Economic Bubbles have far-reaching implications for the study and practice of entrepreneurship and marketing, public and corporate finance, and public policies towards innovation, economy, and finance. It contributes to the defining issues for economic sociology...

  2. Gas and vapor bubble growth and collapse

    International Nuclear Information System (INIS)

    Bonnin, J.; Reali, M.; Sardella, L.

    1976-01-01

    The rate of growth or collapse of a spherical bubble of gas or vapor under the effect of a nonequilibrium with the ambient liquid can be expressed in terms of generalized parameters taking into account either mass or heat diffusion. Diffusion equations have been solved either by numerical computation or under the form of a asymptotical solution, for a growing bubble only and with a constant nonequilibrium. Solutions are compared between them and with already published ones. Experimental results obtained match with a unique nonequilibrium parameter, analogous to a Jacob number. Discrepancies with asymptotical solutions can require in some cases complete numerical computation. But taking into account convection due to bubble lift will require a more sophisticated numerical computation [fr

  3. Chromatographic properties PLOT multicapillary columns.

    Science.gov (United States)

    Nikolaeva, O A; Patrushev, Y V; Sidelnikov, V N

    2017-03-10

    Multicapillary columns (MCCs) for gas chromatography make it possible to perform high-speed analysis of the mixtures of gaseous and volatile substances at a relatively large amount of the loaded sample. The study was performed using PLOT MCCs for gas-solid chromatography (GSC) with different stationary phases (SP) based on alumina, silica and poly-(1-trimethylsilyl-1-propyne) (PTMSP) polymer as well as porous polymers divinylbenzene-styrene (DVB-St), divinylbenzene-vinylimidazole (DVB-VIm) and divinylbenzene-ethylene glycol dimethacrylate (DVB-EGD). These MCCs have the efficiency of 4000-10000 theoretical plates per meter (TP/m) and at a column length of 25-30cm can separate within 10-20s multicomponent mixtures of substances belonging to different classes of chemical compounds. The sample amount not overloading the column is 0.03-1μg and depends on the features of a porous layer. Examples of separations on some of the studied columns are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. A large bubble around the Crab Nebula

    Science.gov (United States)

    Romani, Roger W.; Reach, William T.; Koo, Bon Chul; Heiles, Carl

    1990-01-01

    IRAS and 21 cm observations of the interstellar medium around the Crab nebula show evidence of a large bubble surrounded by a partial shell. If located at the canonical 2 kpc distance of the Crab pulsar, the shell is estimated to have a radius of about 90 pc and to contain about 50,000 solar masses of swept-up gas. The way in which interior conditions of this bubble can have important implications for observations of the Crab are described, and the fashion in which presupernova evolution of the pulsar progenitor has affected its local environment is described.

  5. On the maximum drawdown during speculative bubbles

    Science.gov (United States)

    Rotundo, Giulia; Navarra, Mauro

    2007-08-01

    A taxonomy of large financial crashes proposed in the literature locates the burst of speculative bubbles due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the bulk of drawdown price movement distribution. This paper goes on deeper in the analysis providing a further characterization of the rising part of such selected bubbles through the examination of drawdown and maximum drawdown movement of indices prices. The analysis of drawdown duration is also performed and it is the core of the risk measure estimated here.

  6. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

    This image is of real particle tracks taken from the CERN 2 m liquid hydrogen bubble chamber and shows the production and decay of a negative omega particle. A negative kaon enters the chamber which decays into many particles, including a negative omega that travels a short distance before decaying into more particles. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  7. Bubbling in delay-coupled lasers.

    Science.gov (United States)

    Flunkert, V; D'Huys, O; Danckaert, J; Fischer, I; Schöll, E

    2009-06-01

    We theoretically study chaos synchronization of two lasers which are delay coupled via an active or a passive relay. While the lasers are synchronized, their dynamics is identical to a single laser with delayed feedback for a passive relay and identical to two delay-coupled lasers for an active relay. Depending on the coupling parameters the system exhibits bubbling, i.e., noise-induced desynchronization, or on-off intermittency. We associate the desynchronization dynamics in the coherence collapse and low-frequency fluctuation regimes with the transverse instability of some of the compound cavity's antimodes. Finally, we demonstrate how, by using an active relay, bubbling can be suppressed.

  8. Bubble dynamics in a superheated liquid

    International Nuclear Information System (INIS)

    Sha, W.T.; Shah, V.L.

    1977-09-01

    The report presents an extensive literature survey on bubble dynamics. Growth of a single spherical bubble moving in a uniformly superheated liquid is considered. Equations of motion and energy are presented in the forms that take into consideration the interaction between the motion and the growth. The fourth-order Runge-Kutta method is used to obtain a simultaneous solution of equations of motion and growth rate, and the solution is compared with available experimental results. Results for liquid sodium are presented for a range of pressures and Jakob numbers

  9. Resolving single bubble sonoluminescence flask width

    OpenAIRE

    Arakeri, Vijay H

    1998-01-01

    Single bubble sonoluminescence (SBSL), first studied and observed by Gaitan et al., is the of light emission from a single gas bubble trapped at the pressure maximum of a resonant sound field in a liquid medium, generally water. One of the most striking aspects of SBSL was the estimated optical flash width being less than 50 picoseconds (ps)3; this upper estimate was based on the relative response of a SBSL flash in comparison to a 34 ps laser pulse using a microchannel platephotomultiplier ...

  10. Vapor bubble growth in highly superheated liquid

    International Nuclear Information System (INIS)

    Pavlov, P.A.

    1981-01-01

    Dynamics of the bubble growth in the volume of the uniformally superheated liquid is considered. It is supposed that its growth is hampered by heat transfer. An asymptotic expression for the bubble growth rate at high superheatings when heat hold by liquid is comparable with heat of steam formation, is found by the automodel solution of the heat transfer equation. Writing the radius square in the form of a functional applicable for the calculation of steam formation at the pressure change in superheated liquid is suggested for eveluation calculations [ru

  11. Partial coalescence from bubbles to drops

    KAUST Repository

    Zhang, F. H.

    2015-10-07

    The coalescence of drops is a fundamental process in the coarsening of emulsions. However, counter-intuitively, this coalescence process can produce a satellite, approximately half the size of the original drop, which is detrimental to the overall coarsening. This also occurs during the coalescence of bubbles, while the resulting satellite is much smaller, approximately 10 %. To understand this difference, we have conducted a set of coalescence experiments using xenon bubbles inside a pressure chamber, where we can continuously raise the pressure from 1 up to 85 atm and thereby vary the density ratio between the inner and outer fluid, from 0.005 up to unity. Using high-speed video imaging, we observe a continuous increase in satellite size as the inner density is varied from the bubble to emulsion-droplet conditions, with the most rapid changes occurring as the bubble density grows up to 15 % of that of the surrounding liquid. We propose a model that successfully relates the satellite size to the capillary wave mode responsible for its pinch-off and the overall deformations from the drainage. The wavelength of the primary wave changes during its travel to the apex, with the instantaneous speed adjusting to the local wavelength. By estimating the travel time of this wave mode on the bubble surface, we also show that the model is consistent with the experiments. This wavenumber is determined by both the global drainage as well as the interface shapes during the rapid coalescence in the neck connecting the two drops or bubbles. The rate of drainage is shown to scale with the density of the inner fluid. Empirically, we find that the pinch-off occurs when 60 % of the bubble fluid has drained from it. Numerical simulations using the volume-of-fluid method with dynamic adaptive grid refinement can reproduce these dynamics, as well as show the associated vortical structure and stirring of the coalescing fluid masses. Enhanced stirring is observed for cases with second

  12. Direct numerical simulation of turbulent channel flow with deformed bubbles

    International Nuclear Information System (INIS)

    Yamamoto, Yoshinobu; Kunugi, Tomoaki

    2010-01-01

    In this study, the direct numerical simulation of a fully-developed turbulent channel flow with deformed bubbles were conducted by means of the refined MARS method, turbulent Reynolds number 150, and Bubble Reynolds number 120. As the results, large-scale wake motions were observed round the bubbles. At the bubble located region, mean velocity was degreased and turbulent intensities and Reynolds shear stress were increased by the effects of the large-scale wake motions round bubbles. On the other hands, near wall region, bubbles might effect on the flow laminarlize and drag reduction. Two types of drag coefficient of bubble were estimated from the accelerated velocity of bubble and correlation equation as a function of Particle Reynolds number. Empirical correlation equation might be overestimated the drag effects in this Particle Reynolds number range. (author)

  13. A note on effects of rational bubble on portfolios

    Science.gov (United States)

    Wang, Chan; Nie, Pu-yan

    2018-02-01

    In general, demand increases in wealth and decreases in price in microeconomics. We thereby propose a completely different perspective. By establishing expected utility function of investors, this article introduces one rational bubble asset and one bubble free asset in portfolios and focuses on the effects of bubble on investment portfolios from wealth and price perspectives. All conclusions are obtained by theoretical analysis with microeconomics theory. We argue that inferior goods and Giffen behavior can occur for the bubble free asset in microeconomic fields. The results can help investors to recognize bubble assets and bubble free assets more scientifically. Both bubble and bubble free assets can be inferior goods under some conditions, so we cannot to say which asset better than the other one absolutely.

  14. Motion of air bubbles in stagnant water condition

    International Nuclear Information System (INIS)

    Bezdegumeli, U.; Ozdemir, S.; Yesin, O.

    2004-01-01

    Full text: In this study, air bubble motion in stagnant water condition in a vertical pipe is investigated experimentally. For this purpose, a test set-up was designed and constructed. Motions of single bubbles, having different diameters in the range of 3.0-4.8 mm, were recorded by using a monochrome camera, an image capture card and a PC. Recorded video images were processed to analyse bubble motion and to obtain the necessary data. The purpose of the study is to determine the variation of bubble axial velocity and bubble drag coefficient as a function of equivalent bubble diameter and bubble Reynolds number, Re b . Therefore, detailed information for this range of bubble diameters was obtained. The results have shown good consistency with the previous studies found in the literature

  15. Motion of air bubbles in stagnant water condition

    International Nuclear Information System (INIS)

    Bezdegumeli, U.; Ozdemir, S.; Yesin, O.

    2004-01-01

    In this study, air bubble motion in stagnant water condition in a vertical pipe of 4.6 cm diameter is investigated experimentally. For this purpose, a test set-up was designed and constructed. Motions of single bubbles, having different diameters in the range of 3.0-4.8 mm, were recorded by using a monochrome camera, an image capture card and a PC. Recorded video images were processed to analyse bubble motion and to obtain the necessary data. The purpose of the study is to determine the variation of bubble axial velocity and bubble drag coefficient as a function of equivalent bubble diameter and bubble Reynolds number, Re b . Therefore, detailed information for this range of bubble diameters was obtained. The results have shown good consistency with the previous studies found in the literature. (author)

  16. A three field two fluid CFD model for the bubbly-cap bubble regime

    International Nuclear Information System (INIS)

    Martin Lopez de Bertodano; Xiaodong Sun; Mamoru Ishii; Asim Ulke

    2005-01-01

    Full text of publication follows: The lateral phase distribution of a two phase duct flow in the cap bubble regime is analyzed with a three dimensional three field two-fluid CFD model based on the turbulent k-ε model for bubbly flows developed by Lopez de Bertodano et. al. [2]. The turbulent diffusion of the bubbles is the dominant phase distribution mechanism. A new analytic result is presented to support the development of the model for the bubble induced turbulent diffusion force. New experimental data obtained with a state-of-the-art four sensor miniature conductivity probe are used to validate the two-fluid model. The focus of this work is modeling the transport of the dispersed phase. Previous work (e.g., Lopez de Bertodano et. al.) was focused on the interfacial forces of drag, lift and virtual mass. However, the dispersion of the bubbles by the turbulent eddies of the continuous phase must be considered too. The rigorous formulation of a model for the turbulent dispersion of the bubbles results in a turbulent diffusion force which is obtained from a probability distribution function average (i.e., Boltzmann averaging) of the dispersed phase momentum equation. This force was recently applied to a turbulent bubbly jet with small bubbles (i.e., 1 mm diameter) without adjusting any coefficient. However, the application of this force to industrial conditions (i.e., larger bubbles) requires specific two-phase flow experimental data to calibrate the model due to the uncertainties of the flow around large bubbles. In particular the void distribution and the interfacial area concentration are measured in a mixture of big and small bubbles. The state-of-the-art miniaturized four-sensor conductivity probe developed by Kim et al. [3] is used to obtain the interfacial area concentration in complex two-phase flow situations. This probe can discriminate between small and large bubbles so it offers an opportunity to perform further developments of the multidimensional two

  17. Implementation of Serial and Parallel Bubble Sort on Fpga

    OpenAIRE

    Purnomo, Dwi Marhaendro Jati; Arinaldi, Ahmad; Priyantini, Dwi Teguh; Wibisono, Ari; Febrian, Andreas

    2016-01-01

    Sorting is common process in computational world. Its utilization are on many fields from research to industry. There are many sorting algorithm in nowadays. One of the simplest yet powerful is bubble sort. In this study, bubble sort is implemented on FPGA. The implementation was taken on serial and parallel approach. Serial and parallel bubble sort then compared by means of its memory, execution time, and utility which comprises slices and LUTs. The experiments show that serial bubble sort r...

  18. Negative wake behind bubbles in non-newtonian liquids

    DEFF Research Database (Denmark)

    Hassager, Ole

    1979-01-01

    Gas bubbles rising by gravity in non-Newtonian elastic liquids are different to gas bubbles in viscous Newtonian fluids in at least two ways. First, the bubbles in the non-Newtonian liquids often have a peculiar tip at the rear pole, and second, the terminal rise velocity versus volume curve ofte...

  19. Gas pressure in bubble attached to tube circular outlet

    OpenAIRE

    Salonen, A; Gay, Cyprien; Maestro, A; Drenckhan, W; Rio, Emmanuelle

    2016-01-01

    In the present Supplementary notes to our work ``Arresting bubble coarsening: A two-bubble experiment to investigate grain growth in presence of surface elasticity'' (accepted in EPL), we derive the expression of the gas pressure inside a bubble located above and attached to the circular outlet of a vertical tube.

  20. The Milky Way Project: A Census of Small Bubbles

    Science.gov (United States)

    Arvidsson, Kim; Wolf-Chase, G. A.; Way Project, Milky

    2013-01-01

    The first data release (DR1) from the Milky Way Project (MWP) contains 1362 visually identified small bubbles drawn by users. These small infrared bubbles typically have diameters MSX6C point source catalog; >90% of all small bubbles are MSX point sources.

  1. Optical measurement of bubbles: System design and application

    NARCIS (Netherlands)

    Leifer, I.; Leeuw, G.de; Cohen, L.H.

    2003-01-01

    Affordable high quality charge-coupled device (CCD) video cameras and image processing software are powerful tools for bubble measurements. Because of the wide variation between bubble populations, different bubble measurement systems (BMSs) are required depending upon the application. Two BMSs are

  2. Numerical simulation of single bubble dynamics under acoustic travelling waves.

    Science.gov (United States)

    Ma, Xiaojian; Huang, Biao; Li, Yikai; Chang, Qing; Qiu, Sicong; Su, Zheng; Fu, Xiaoying; Wang, Guoyu

    2018-04-01

    The objective of this paper is to apply CLSVOF method to investigate the single bubble dynamics in acoustic travelling waves. The Naiver-Stokes equation considering the acoustic radiation force is proposed and validated to capture the bubble behaviors. And the CLSVOF method, which can capture the continuous geometric properties and satisfies mass conservation, is applied in present work. Firstly, the regime map, depending on the dimensionless acoustic pressure amplitude and acoustic wave number, is constructed to present different bubble behaviors. Then, the time evolution of the bubble oscillation is investigated and analyzed. Finally, the effect of the direction and the damping coefficient of acoustic wave propagation on the bubble behavior are also considered. The numerical results show that the bubble presents distinct oscillation types in acoustic travelling waves, namely, volume oscillation, shape oscillation, and splitting oscillation. For the splitting oscillation, the formation of jet, splitting of bubble, and the rebound of sub-bubbles may lead to substantial increase in pressure fluctuations on the boundary. For the shape oscillation, the nodes and antinodes of the acoustic pressure wave contribute to the formation of the "cross shape" of the bubble. It should be noted that the direction of the bubble translation and bubble jet are always towards the direction of wave propagation. In addition, the damping coefficient causes bubble in shape oscillation to be of asymmetry in shape and inequality in size, and delays the splitting process. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Bubbles as a means for the deaeration of water bodies

    NARCIS (Netherlands)

    Zhang, Yuhang; Zhou, Gedi; Prosperetti, Andrea

    2017-01-01

    Occasional dissolved-air supersaturation - such as may occur, for instance, downstream of dams - is harmful to fish because it causes gas bubble disease. A counterintuitive but effective means of reducing dissolved air content is the injection of bubbles in the supersaturated water. The bubbles

  4. Nasal continuous positive airway pressure: does bubbling improve gas exchange?

    Science.gov (United States)

    Morley, C J; Lau, R; De Paoli, A; Davis, P G

    2005-07-01

    In a randomised crossover trial, 26 babies, treated with Hudson prong continuous positive airway pressure (CPAP) from a bubbling bottle, received vigorous, high amplitude, or slow bubbling for 30 minutes. Pulse oximetry, transcutaneous carbon dioxide, and respiratory rate were recorded. The bubbling rates had no effect on carbon dioxide, oxygenation, or respiratory rate.

  5. A mathematical definition of the financial bubbles and crashes

    Science.gov (United States)

    Watanabe, Kota; Takayasu, Hideki; Takayasu, Misako

    2007-09-01

    We check the validity of the mathematical method of detecting financial bubbles or crashes, which is based on a data fitting with an exponential function. We show that the period of a bubble can be determined nearly uniquely independent of the precision of data. The method is widely applicable for stock market data such as the Internet bubble.

  6. Air bubble migration is a random event post embryo transfer.

    Science.gov (United States)

    Confino, E; Zhang, J; Risquez, F

    2007-06-01

    Air bubble location following embryo transfer (ET) is the presumable placement spot of embryos. The purpose of this study was to document endometrial air bubble position and migration following embryo transfer. Multicenter prospective case study. Eighty-eight embryo transfers were performed under abdominal ultrasound guidance in two countries by two authors. A single or double air bubble was loaded with the embryos using a soft, coaxial, end opened catheters. The embryos were slowly injected 10-20 mm from the fundus. Air bubble position was recorded immediately, 30 minutes later and when the patient stood up. Bubble marker location analysis revealed a random distribution without visible gravity effect when the patients stood up. The bubble markers demonstrated splitting, moving in all directions and dispersion. Air bubbles move and split frequently post ET with the patient in the horizontal position, suggestive of active uterine contractions. Bubble migration analysis supports a rather random movement of the bubbles and possibly the embryos. Standing up changed somewhat bubble configuration and distribution in the uterine cavity. Gravity related bubble motion was uncommon, suggesting that horizontal rest post ET may not be necessary. This report challenges the common belief that a very accurate ultrasound guided embryo placement is mandatory. The very random bubble movement observed in this two-center study suggests that a large "window" of embryo placement maybe present.

  7. The interaction between multiple bubbles and the free surface

    International Nuclear Information System (INIS)

    Zhang Aman; Yao Xiongliang

    2008-01-01

    The flow is assumed to be potential, and a boundary integral method is used to solve the Laplace equation for the velocity potential to investigate the shape and the position of the bubble. A 3D code to study the bubble dynamics is developed, and the calculation results agree well with the experimental data. Numerical analyses are carried out for the interaction between multiple bubbles near the free surface including in-phase and out-of-phase bubbles. The calculation result shows that the bubble period increases with the decrease of the distance between bubble centres because of the depression effect between multiple bubbles. The depression has no relationship with the free surface and it is more apparent for out-of-phase bubbles. There are great differences in dynamic behaviour between the in-phase bubbles and the out-of-phase bubbles due to the depression effect. Furthermore, the interaction among eight bubbles is simulated with a three-dimensional model, and the evolving process and the relevant physical phenomena are presented. These phenomena can give a reference to the future work on the power of bubbles induced by multiple charges exploding simultaneously or continuously

  8. Effects of bubbling operations on a thermally stratified reservoir: implications for water quality amelioration.

    Science.gov (United States)

    Fernandez, R L; Bonansea, M; Cosavella, A; Monarde, F; Ferreyra, M; Bresciano, J

    2012-01-01

    Artificial thermal mixing of the water column is a common method of addressing water quality problems with the most popular method of destratification being the bubble curtain. The air or oxygen distribution along submerged multiport diffusers is based on similar basic principles as those of outfall disposal systems. Moreover, the disposal of sequestered greenhouse gases into the ocean, as recently proposed by several researchers to mitigate the global warming problem, requires analogous design criteria. In this paper, the influence of a bubble-plume is evaluated using full-scale temperature and water quality data collected in San Roque Reservoir, Argentina. A composite system consisting of seven separated diffusers connected to four 500 kPa compressors was installed at this reservoir by the end of 2008. The original purpose of this air bubble system was to reduce the stratification, so that the water body may completely mix under natural phenomena and remain well oxygenated throughout the year. By using a combination of the field measurements and modelling, this work demonstrates that thermal mixing by means of compressed air may improve water quality; however, if improperly sized or operated, such mixing can also cause deterioration. Any disruption in aeration during the destratification process, for example, may result in a reduction of oxygen levels due to the higher hypolimnetic temperatures. Further, the use of artificial destratification appears to have insignificant influence on reducing evaporation rates in relatively shallow impoundments such as San Roque reservoir.

  9. Behavior and dynamics of bubble breakup in gas pipeline leaks and accidental subsea oil well blowouts.

    Science.gov (United States)

    Wang, Binbin; Socolofsky, Scott A; Lai, Chris C K; Adams, E Eric; Boufadel, Michel C

    2018-06-01

    Subsea oil well blowouts and pipeline leaks release oil and gas to the environment through vigorous jets. Predicting the breakup of the released fluids in oil droplets and gas bubbles is critical to predict the fate of petroleum compounds in the marine water column. To predict the gas bubble size in oil well blowouts and pipeline leaks, we observed and quantified the flow behavior and breakup process of gas for a wide range of orifice diameters and flow rates. Flow behavior at the orifice transitions from pulsing flow to continuous discharge as the jet crosses the sonic point. Breakup dynamics transition from laminar to turbulent at a critical value of the Weber number. Very strong pure gas jets and most gas/liquid co-flowing jets exhibit atomization breakup. Bubble sizes in the atomization regime scale with the jet-to-plume transition length scale and follow -3/5 power-law scaling for a mixture Weber number. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Making continuous bubble type polyethylene foam incombustible

    International Nuclear Information System (INIS)

    Kaji, Kanako; Hatada, Motoyoshi; Yoshizawa, Iwao; Komai, Kuniaki; Kohara, Choji.

    1989-01-01

    Since continuous bubble type plastic foam has excellent compression characteristics and sound absorption characteristics, it has been widely used as cushion material, sealing material, sound insulating material and so on. However, the most part of plastic foam is taken by air, therefore at the time of fires, it becomes a very dangerous material. At present, the material used mostly as the seat cushions for airliners, railroad coaches, automobiles and others is polyurethane foam, but since it contains C-N couples in its molecules, it is feared to generate cyanic gas according to the condition of combustion. As the plastic foam that does not generate harmful gas at the time of fires, there is continuous bubble type polyethylene which is excellent in its weathering property and chemical resistance. A reactive, phosphorus-containing oligomer has large molecular weight and two or more double couplings in a molecule, therefore, it does not enter the inside of polyethylene, and polymerizes and crosslinks on the surfaces of bubble walls in the foam, accordingly it is expected that the apparent graft polymerization is carried out, and it is very effective for making polyethylene foam incombustible. The method of making graft foam, the properties of graft foam and so on are reported. When the graft polymerization of this oligomer to continuous bubble type polyethylene foam was tried, highly incombustible polyethylene foam was obtained. (K.I.)

  11. Bubbles in piezo-acoustic inkjet printing

    NARCIS (Netherlands)

    Lohse, D.; Jeurissen, R.J.M.; de Jong, J.; Versluis, M.; Wijshoff, H.M.A.; van den Berg, M.; Reinten, H.

    2008-01-01

    Ink-jet printing is considered as the hitherto most successful application of microfluidics. A notorious problem in piezo-acoustic ink-jet systems is the formation of air bubbles during operation. They seriously disturb the acoustics and can cause the droplet formation to stop. We could show by a

  12. Non-Abelian bubbles in microstate geometries

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez, Pedro F. [Instituto de Física Teórica UAM/CSIC,C/ Nicolás Cabrera, 13-15, C.University Cantoblanco, E-28049 Madrid (Spain); Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS,Orme des Merisiers bâtiment 774, F-91191 Gif-sur-Yvette (France)

    2016-11-24

    We find the first smooth bubbling microstate geometries with non-Abelian fields. The solutions constitute an extension of the BPS three-charge smooth microstates. These consist in general families of regular supersymmetric solutions with non-trivial topology, i.e. bubbles, of N=1, d=5 Super-Einstein-Yang-Mills theory, having the asymptotic charges of a black hole or black ring but with no horizon. The non-Abelian fields make their presence at the very heart of the microstate structure: the physical size of the bubbles is affected by the non-Abelian topological charge they carry, which combines with the Abelian flux threading the bubbles to hold them up. Interestingly the non-Abelian fields carry a set of adjustable continuous parameters that do not alter the asymptotics of the solutions but modify the local geometry. This feature can be used to obtain a classically infinite number of microstate solutions with the asymptotics of a single black hole or black ring.

  13. Customized bubble continuous positive airway pressure (BCPAP ...

    African Journals Online (AJOL)

    owner

    2013-02-09

    Feb 9, 2013 ... our institution, we modified the existing Bubble CPAP devise using readily available but far less expensive materials. The resultant product is cheap, easily assem- .... Hurd SS, Bryan MH, Cotton RB,. Epstein MF et al. is chronic lung disease in low birth weight infants preventable? Pediatrics 1987; 9. (1):26- ...

  14. Bubble and Drop Nonlinear Dynamics (BDND)

    Science.gov (United States)

    Trinh, E. H.; Leal, L. Gary; Thomas, D. A.; Crouch, R. K.

    1998-01-01

    Free drops and bubbles are weakly nonlinear mechanical systems that are relatively simple to characterize experimentally in 1-G as well as in microgravity. The understanding of the details of their motion contributes to the fundamental study of nonlinear phenomena and to the measurement of the thermophysical properties of freely levitated melts. The goal of this Glovebox-based experimental investigation is the low-gravity assessment of the capabilities of a modular apparatus based on ultrasonic resonators and on the pseudo- extinction optical method. The required experimental task is the accurate measurements of the large-amplitude dynamics of free drops and bubbles in the absence of large biasing influences such as gravity and levitation fields. A single-axis levitator used for the positioning of drops in air, and an ultrasonic water-filled resonator for the trapping of air bubbles have been evaluated in low-gravity and in 1-G. The basic feasibility of drop positioning and shape oscillations measurements has been verified by using a laptop-interfaced automated data acquisition and the optical extinction technique. The major purpose of the investigation was to identify the salient technical issues associated with the development of a full-scale Microgravity experiment on single drop and bubble dynamics.

  15. THE AGE OF THE LOCAL INTERSTELLAR BUBBLE

    International Nuclear Information System (INIS)

    Abt, Helmut A.

    2011-01-01

    The Local Interstellar Bubble is an irregular region from 50 to 150 pc from the Sun in which the interstellar gas density is 10 -2 -10 -3 of that outside the bubble and the interstellar temperature is 10 6 K. Evidently most of the gas was swept out by one or more supernovae. I explored the stellar contents and ages of the region from visual double stars, spectroscopic doubles, single stars, open clusters, emission regions, X-ray stars, planetary nebulae, and pulsars. The bubble has three sub-regions. The region toward the galactic center has stars as early as O9.5 V and with ages of 2-4 M yr. It also has a pulsar (PSRJ1856-3754) with a spin-down age of 3.76 Myr. That pulsar is likely to be the remnant of the supernova that drove away most of the gas. The central lobe has stars as early as B7 V and therefore an age of about 160 Myr or less. The Pleiades lobe has stars as early as B3 and therefore an age of about 50 Myr. There are no obvious pulsars that resulted from the supernovae that cleared out those areas. As found previously by Welsh and Lallement, the bubble has five B stars along its perimeter that show high-temperature ions of O VI and C II along their lines of sight, confirming its high interstellar temperature.

  16. The bubble distribution in glass refining channels

    Czech Academy of Sciences Publication Activity Database

    Němec, Lubomír; Cincibusová, P.

    2005-01-01

    Roč. 49, č. 4 (2005), s. 269-277 ISSN 0862-5468 Institutional research plan: CEZ:AV0Z40320502 Keywords : glass fining * bubble distribution s models * horizontal channel Subject RIV: CA - Inorganic Chemistry Impact factor: 0.463, year: 2005

  17. Argonne Bubble Experiment Thermal Model Development II

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-01

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at three beam power levels, 6, 12 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was observed. This report will describe the Computational Fluid Dynamics (CFD) model that was developed to calculate the temperatures and gas volume fractions in the solution vessel during the irradiations. The previous report described an initial analysis performed on a geometry that had not been updated to reflect the as-built solution vessel. Here, the as-built geometry is used. Monte-Carlo N-Particle (MCNP) calculations were performed on the updated geometry, and these results were used to define the power deposition profile for the CFD analyses, which were performed using Fluent, Ver. 16.2. CFD analyses were performed for the 12 and 15 kW irradiations, and further improvements to the model were incorporated, including the consideration of power deposition in nearby vessel components, gas mixture composition, and bubble size distribution. The temperature results of the CFD calculations are compared to experimental measurements.

  18. Organization of bubble chamber image processing

    International Nuclear Information System (INIS)

    Gritsaenko, I.A.; Petrovykh, L.P.; Petrovykh, Yu.L.; Fenyuk, A.B.

    1985-01-01

    A programme of bubble chamber image processing is described. The programme is written in FORTRAN, it is developed for the DEC-10 computer and is designed for operation of semi-automation processing-measurement projects PUOS-2 and PUOS-4. Fornalization of the image processing permits to use it for different physical experiments

  19. Ultrasound induced by CW laser cavitation bubbles

    International Nuclear Information System (INIS)

    Korneev, N; Montero, P Rodriguez; Ramos-Garcia, R; Ramirez-San-Juan, J C; Padilla-Martinez, J P

    2011-01-01

    The generation of ultrasound by a collapsing single cavitation bubble in a strongly absorbing liquid illuminated with a moderate power CW laser is described. The ultrasound shock wave is detected with hydrophone and interferometric device. To obtain a stronger pulse it is necessary to adjust a liquid absorption and a beam diameter. Their influence can be qualitatively understood with a simple model.

  20. Heat transport in bubbling turbulent convection.

    Science.gov (United States)

    Lakkaraju, Rajaram; Stevens, Richard J A M; Oresta, Paolo; Verzicco, Roberto; Lohse, Detlef; Prosperetti, Andrea

    2013-06-04

    Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to numerous mechanisms, many of which are not understood in quantitative detail. An important component of the overall process is that the buoyancy of the bubble compounds with that of the liquid to give rise to a much-enhanced natural convection. In this article, we focus specifically on this enhancement and present a numerical study of the resulting two-phase Rayleigh-Bénard convection process in a cylindrical cell with a diameter equal to its height. We make no attempt to model other aspects of the boiling process such as bubble nucleation and detachment. The cell base and top are held at temperatures above and below the boiling point of the liquid, respectively. By keeping this difference constant, we study the effect of the liquid superheat in a Rayleigh number range that, in the absence of boiling, would be between 2 × 10(6) and 5 × 10(9). We find a considerable enhancement of the heat transfer and study its dependence on the number of bubbles, the degree of superheat of the hot cell bottom, and the Rayleigh number. The increased buoyancy provided by the bubbles leads to more energetic hot plumes detaching from the cell bottom, and the strength of the circulation in the cell is significantly increased. Our results are in general agreement with recent experiments on boiling Rayleigh-Bénard convection.

  1. Is there a Housing Bubble in Turkey?

    Directory of Open Access Journals (Sweden)

    Coskun Yener

    2017-03-01

    Full Text Available There was a notable housing price inflation in aggregate/local levels in Turkey during the last few years. Although the country’s economic fundamentals remain strong, the probability of a housing bubble is a heated debate among market participants. This timely investigation brings greater clarity to whether the Turkish housing market is in a bubble. The study uses a multi-strand approach to dissect the bubble over the period of Jan. 2010 - Dec. 2014. First, monthly/annual price-to-income and monthly price-to-rent ratios are examined for the national Turkish as well as regional Istanbul, Izmir and Ankara housing markets. Second, an extended CASE and SHILLER (2003 model is applied assessing the interdependence between housing prices and a series of explanatory variables. Lastly, the Right Tail Augmented Dickey-Fuller (Rtadf test is performed to support the overall analysis. This study finds that neither affordability ratios nor regression estimates support the existence of the bubble in Turkey.

  2. Condensation of vapor bubble in subcooled pool

    Science.gov (United States)

    Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

    2017-02-01

    We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

  3. Radiolytic and thermolytic bubble gas hydrogen composition

    Energy Technology Data Exchange (ETDEWEB)

    Woodham, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-12-11

    This report describes the development of a mathematical model for the estimation of the hydrogen composition of gas bubbles trapped in radioactive waste. The model described herein uses a material balance approach to accurately incorporate the rates of hydrogen generation by a number of physical phenomena and scale the aforementioned rates in a manner that allows calculation of the final hydrogen composition.

  4. Is Education Facing a "Tech Bubble"?

    Science.gov (United States)

    Davis, Michelle R.

    2013-01-01

    Educational technology companies and entrepreneurs may face the risk of a "tech bubble," similar to the massive boom-and-bust that rocked the technology market in the late 1990s, according to market analysts and a recently released paper. A relatively new focus on K-12 educational technology as an investment vehicle, a surge of investors looking…

  5. Image digitizer system for bubble chamber laser

    International Nuclear Information System (INIS)

    Haggerty, H.

    1986-01-01

    An IBM PC-based image digitizer system has been assembled to monitor the laser flash used for holography at the 15 foot bubble chamber. The hardware and the operating software are outlined. For an operational test of the system, an array of LEDs was flashed with a 10 microsecond pulse and the image was grabbed by one of the operating programs and processed

  6. Bubbles That Change the Speed of Sound

    Science.gov (United States)

    Planinsic, Gorazd; Etkina, Eugenia

    2012-01-01

    The influence of bubbles on sound has long attracted the attention of physicists. In his 1920 book Sir William Bragg described sound absorption caused by foam in a glass of beer tapped by a spoon. Frank S. Crawford described and analyzed the change in the pitch of sound in a similar experiment and named the phenomenon the "hot chocolate effect."…

  7. BUBBLE - an urban boundary layer meteorology project

    DEFF Research Database (Denmark)

    Rotach, M.W.; Vogt, R.; Bernhofer, C.

    2005-01-01

    ground truth, as well as on urban turbulence and profiling (sodar, RASS, tethered balloon) were performed. Also tracer experiments with near-roof-level release and sampling were performed. In parallel to the experimental activities within BUBBLE, a meso-scale numerical atmospheric model, which contains...

  8. Heat transport in bubbling turbulent convection

    NARCIS (Netherlands)

    Lakkaraju, R.; Stevens, Richard Johannes Antonius Maria; Oresta, P.; Verzicco, Roberto; Lohse, Detlef; Prosperetti, Andrea

    2013-01-01

    Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to numerous mechanisms, many of which are not understood in quantitative detail. An important component of the overall process is that the buoyancy of the bubble compounds with that of the liquid to

  9. Partial coalescence from bubbles to drops

    KAUST Repository

    Zhang, F. H.; Thoraval, Marie-Jean; Thoroddsen, Sigurdur T; Taborek, P.

    2015-01-01

    the travel time of this wave mode on the bubble surface, we also show that the model is consistent with the experiments. This wavenumber is determined by both the global drainage as well as the interface shapes during the rapid coalescence in the neck

  10. Drop impact entrapment of bubble rings

    KAUST Repository

    Thoraval, M.-J.; Takehara, K.; Etoh, T.G.; Thoroddsen, Sigurdur T

    2013-01-01

    We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et

  11. Effects of pH on nano-bubble stability and transport in saturated porous media

    Science.gov (United States)

    Hamamoto, Shoichiro; Takemura, Takato; Suzuki, Kenichiro; Nishimura, Taku

    2018-01-01

    An understanding of nano-scale bubble (NB) transport in porous media is important for potential application of NBs in soil/groundwater remediation. It is expected that the solution chemistry of NB water highly influences the surface characteristics of NBs and porous media and the interaction between them, thus affecting the stability and transport characteristics of NB. In this study, in addition to stability experiments, one-dimensional column transport experiments using glass beads were conducted to investigate the effects of pH on the NB transport behavior. The results showed that the NBs were more stable under higher pH. Column transport experiments revealed that entrapment of NBs, especially larger ones, was enhanced in lower-pH water, likely suggesting pH-dependent NB attachment and physical straining, both of which are also probably influenced by bubble size. Although relatively smaller NBs were released after switching the eluting fluid to one with lower ionic strength, most of the NBs in lower-pH water were still retained in the porous media even altering the chemical condition.

  12. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya

    2016-01-01

    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  13. Studies of column supported towers

    International Nuclear Information System (INIS)

    Chauvel, D.; Costaz, J.-L.

    1991-01-01

    As a result of a research and development programme into the civil engineering of cooling towers launched in 1978 by Electricite de France, very high cooling towers were built at Golfech and Chooz, in France, using column supports. This paper discusses the evolution of this new type of support from classical diagonal supports, presents some of the results of design calculations and survey measurements taken during construction of the shell and analyses the behaviour of the structure. (author)

  14. Cap Bubble Drift Velocity in a Confined Test Section

    International Nuclear Information System (INIS)

    Xiaodong Sun; Seungjin Kim; Mamoru Ishii; Lincoln, Frank W.; Beus, Stephen G.

    2002-01-01

    In the two-group interfacial area transport equation, bubbles are categorized into two groups, i.e., spherical/distorted bubbles as group 1 and cap/slug/churn-turbulent bubbles as group 2. The bubble rise velocities for both groups of bubbles may be estimated by the drift flux model by applying different distribution parameters and drift velocities for both groups. However, the drift velocity for group 2 bubbles is not always applicable (when the wall effect becomes important) as in the current test loop of interest where the flow channel is confined by two parallel flat walls, with a dimension of 200-mm in width and 10-mm in gap. The previous experiments indicated that no stable slug flow existed in this test section, which was designed to permit visualization of the flow patterns and bubble characteristics without the distortion associated with curved surfaces. In fact, distorted cap bubbly and churn-turbulent flow was observed. Therefore, it is essential to developed a correlation for cap bubble drift velocity in this confined flow channel. Since the rise velocity of a cap bubble depends on its size, a high-speed movie camera is used to capture images of cap bubbles to obtain the bubble size information. Meanwhile, the rise velocity of cap and elongated bubbles (called cap bubbles hereafter) is investigated by examining the captured images frame by frame. As a result, the conventional correlation of drift velocity for slug bubbles is modified and acceptable agreements between the measurements and correlation estimation are achieved

  15. Bubbles with shock waves and ultrasound: a review.

    Science.gov (United States)

    Ohl, Siew-Wan; Klaseboer, Evert; Khoo, Boo Cheong

    2015-10-06

    The study of the interaction of bubbles with shock waves and ultrasound is sometimes termed 'acoustic cavitation'. It is of importance in many biomedical applications where sound waves are applied. The use of shock waves and ultrasound in medical treatments is appealing because of their non-invasiveness. In this review, we present a variety of acoustics-bubble interactions, with a focus on shock wave-bubble interaction and bubble cloud phenomena. The dynamics of a single spherically oscillating bubble is rather well understood. However, when there is a nearby surface, the bubble often collapses non-spherically with a high-speed jet. The direction of the jet depends on the 'resistance' of the boundary: the bubble jets towards a rigid boundary, splits up near an elastic boundary, and jets away from a free surface. The presence of a shock wave complicates the bubble dynamics further. We shall discuss both experimental studies using high-speed photography and numerical simulations involving shock wave-bubble interaction. In biomedical applications, instead of a single bubble, often clouds of bubbles appear (consisting of many individual bubbles). The dynamics of such a bubble cloud is even more complex. We shall show some of the phenomena observed in a high-intensity focused ultrasound (HIFU) field. The nonlinear nature of the sound field and the complex inter-bubble interaction in a cloud present challenges to a comprehensive understanding of the physics of the bubble cloud in HIFU. We conclude the article with some comments on the challenges ahead.

  16. SPEEDUPtrademark ion exchange column model

    International Nuclear Information System (INIS)

    Hang, T.

    2000-01-01

    A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUptrademark software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLigtrademark ion exchange resins, once the experimental data are complete

  17. A derivation of the stable cavitation threshold accounting for bubble-bubble interactions.

    Science.gov (United States)

    Guédra, Matthieu; Cornu, Corentin; Inserra, Claude

    2017-09-01

    The subharmonic emission of sound coming from the nonlinear response of a bubble population is the most used indicator for stable cavitation. When driven at twice their resonance frequency, bubbles can exhibit subharmonic spherical oscillations if the acoustic pressure amplitude exceeds a threshold value. Although various theoretical derivations exist for the subharmonic emission by free or coated bubbles, they all rest on the single bubble model. In this paper, we propose an analytical expression of the subharmonic threshold for interacting bubbles in a homogeneous, monodisperse cloud. This theory predicts a shift of the subharmonic resonance frequency and a decrease of the corresponding pressure threshold due to the interactions. For a given sonication frequency, these results show that an optimal value of the interaction strength (i.e. the number density of bubbles) can be found for which the subharmonic threshold is minimum, which is consistent with recently published experiments conducted on ultrasound contrast agents. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Observation of high-temperature bubbles in an ECR plasma

    Science.gov (United States)

    Terasaka, K.; Yoshimura, S.; Tanaka, M. Y.

    2018-05-01

    Creation and annihilation of high-temperature bubbles have been observed in an electron cyclotron resonance plasma. The electron temperature in the bubble core is three times higher than that in the ambient region, and the size perpendicular to the magnetic field is much smaller than the plasma diameter. Formation of a bubble accompanies large negative spikes in the floating potential of a Langmuir probe, and the spatiotemporal behavior of the bubble has been visualized with a high-impedance wire grid detector. It is found that the bubble is in a prolate spheroidal shape with the axis along the magnetic field and occurs randomly in time and independently in space.

  19. Investigation of the condensing vapor bubble behavior through CFD simulation

    International Nuclear Information System (INIS)

    Sablania, Sidharth; Verma, Akash; Goyal, P.; Dutta, Anu; Singh, R.K.

    2013-09-01

    In nuclear systems the sub-cooled boiling flow is an important problem due to the behavior of condensing vapor bubble which has a large effect on the heat transfer characteristics as well as pressure drops and flow instability. The sub-cooled boiling flows become very complex and dynamic phenomena by the vapor bubble-water interaction. This happens due to the boiling/condensation, break-up, and coalescence of the bubble and needs to be addressed for characterizing the above mentioned flow parameters. There have been many researches to analyze the behavior of bubble experimentally and analytically. However, it is very difficult to get complete information about the behavior of bubble because of ever changing interface between vapor and water phase due to bubble condensation/evaporation Therefore, it is necessary to carry out a CFD simulation for better understanding the complex phenomenon of the bubble behavior. The present work focuses on the simulation of condensing bubble in subcooled boiling flow using (Volume of Fluid) VOF method in the CFD code CFD-ACE+. In order to simulate the heat and mass transfer through the bubble interface, CFD modeling for the bubble condensation was developed by modeling the source terms in the governing equations of VOF model using the User-Defined Function (UDF) in CFD-ACE+ code. The effect of condensation on bubble behavior was analyzed by comparing the behavior of condensing bubble with that of adiabatic bubble. It was observed that the behavior of condensing bubble was different from that of non condensing bubble in respect of bubble shape, diameter, velocity etc. The results obtained from the present simulation in terms of various parameters such as bubble velocity, interfacial area and bubble volume agreed well with the reported experimental results verified with FLUENT code in available literature. Hence, this CFD-ACE+ simulation of single bubble condensation will be a useful computational fluid dynamics tool for analyzing the

  20. The effect of ion irradiation on inert gas bubble mobility

    International Nuclear Information System (INIS)

    Alexander, D.E.; Birtcher, R.C.

    1991-09-01

    The effect of Al ion irradiation on the mobility of Xe gas bubbles in Al thin films was investigated. Transmission electron microscopy was used to determine bubble diffusivities in films irradiated and/or annealed at 673K, 723K and 773K. Irradiation increased bubble diffusivity by a factor of 2--9 over that due to thermal annealing alone. The Arrhenius behavior and dose rate dependence of bubble diffusivity are consistent with a radiation enhanced diffusion phenomenon affecting a volume diffusion mechanism of bubble transport. 9 refs., 3 figs., 2 tabs