WorldWideScience

Sample records for superficial gas velocities

  1. Effects of superficial gas velocity and fluid property on the ...

    African Journals Online (AJOL)

    In the present study, the influence of superficial gas velocity and fluid properties on gas holdup and liquid circulation velocity in a three-phase external loop airlift column using polystyrene (0.0036 m diameter and 1025.55 kg/m3 density) and nylon-6 (0.0035 m diameter and 1084.24 kg/m3 density) particles with aqueous ...

  2. The effects of baffles and gas superficial velocity on a bubble fluidized bed reactor's applications

    International Nuclear Information System (INIS)

    Ghorbanpour, A.; Ghannadi Maragheh, M.; Mallah, M. H.

    2008-01-01

    Baffles are used for decreasing bubbles diameter in order to increase the conversion rate along the bubbling fluidized bed reactors. The appearance of this phenomenon is due to bursting of the bubbles during the pass of bubbles from baffles. In this work, a computerized modeling and simulation have been performed in order to obtain a fundamental knowledge of the influence of the baffles on the bubble diameter and the specific mass transfer area. The height of the bed is 5 meters and its diameter is 0.3 meter. Baffles are located at 1 and 2 meters from the bottom of the bed. A two phase model together with a comprehensive fluid dynamical description of bubbling fluidized is presented. The effects of baffles and gas superficial velocity on the operating behavior of fluidized bed reactors are considered. The results are compared to the previously reported documents, and the experiments which have been carried out. MATLAB software is used in this simulation

  3. High Velocity Gas Gun

    Science.gov (United States)

    1988-01-01

    A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

  4. Biomass torrefaction characteristics in inert and oxidative atmospheres at various superficial velocities.

    Science.gov (United States)

    Chen, Wei-Hsin; Lu, Ke-Miao; Liu, Shih-Hsien; Tsai, Chi-Ming; Lee, Wen-Jhy; Lin, Ta-Chang

    2013-10-01

    The reaction characteristics of four biomass materials (i.e. oil palm fiber, coconut fiber, eucalyptus, and Cryptomeria japonica) with non-oxidative and oxidative torrefaction at various superficial velocities are investigated where nitrogen and air are used as carrier gases. Three torrefaction temperatures of 250, 300, and 350 °C are considered. At a given temperature, the solid yield of biomass is not affected by N2 superficial velocity, revealing that the thermal degradation is controlled by heat and mass transfer in biomass. Increasing air superficial velocity decreases the solid yield, especially in oil palm fiber and coconut fiber, implying that the torrefaction reaction of biomass is dominated by surface oxidation. There exists an upper limit of air superficial velocity in the decrement of solid yield, suggesting that beyond this limit the thermal degradation of biomass is no longer governed by surface oxidation, but rather is controlled by internal mass transport. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Effects of pressure drop and superficial velocity on the bubbling fluidized bed incinerator.

    Science.gov (United States)

    Wang, Feng-Jehng; Chen, Suming; Lei, Perng-Kwei; Wu, Chung-Hsing

    2007-12-01

    Since performance and operational conditions, such as superficial velocity, pressure drop, particles viodage, and terminal velocity, are difficult to measure on an incinerator, this study used computational fluid dynamics (CFD) to determine numerical solutions. The effects of pressure drop and superficial velocity on a bubbling fluidized bed incinerator (BFBI) were evaluated. Analytical results indicated that simulation models were able to effectively predict the relationship between superficial velocity and pressure drop over bed height in the BFBI. Second, the models in BFBI were simplified to simulate scale-up beds without excessive computation time. Moreover, simulation and experimental results showed that minimum fluidization velocity of the BFBI must be controlled in at 0.188-3.684 m/s and pressure drop was mainly caused by bed particles.

  6. Air-water flow in a vertical pipe with sudden changes of superficial water velocity

    International Nuclear Information System (INIS)

    Horst-Michael Prasser; Eckhard Krepper; Thomas Frank

    2005-01-01

    Full text of publication follows: For further model development and the validation of CFD codes for two-phase flow applications experiments were carried out with a sudden change of the superficial velocity of water. The tests were performed in a vertical pipe of 51.2 mm diameter. The gas was injected through 19 capillaries of 0.8 mm inner diameter equally distributed over the cross section of the pipe. Measurements were taken by two wire-mesh sensors (24 x 24 points, 2500 Hz) mounted in a short distance (16 mm) behind each other. This sensor assembly was placed 3030 mm downstream of the gas injection. The change of the superficial water velocity was produced by a butterfly valve, the flap of which was perforated. In this way, a rapid closure of the valve caused a jump-like reduction of the liquid flow rate. The valve was located upstream of the gas injection. In a second series of tests a jump-like increase of the water flow rate was studied. Time sequences of the gas fraction profile were calculated from the wire-mesh sensor data over sampling periods of 0.2 s per profile. To increase the statistical reliability of the data, the transient was repeated several times and the data superposed (ensemble averaging). Gas velocity distributions were determined by correlation of the signals with the measurements of the second sensor. The tests enable the observation of the restructuring process of bubbly flow between two steady state conditions. The process is subdivided into three main stages: (1) the undisturbed flow before the velocity jump, (2) the passage of the bubbly flow formed under initial conditions, but travelling with the new velocity and (3) the bubbly flow generated under the new boundary conditions. Transient behaviour between these stages is reflected by the measured data. Special attention was paid to stage 2, where the radial gas fraction profiles change shape due to the excitation of the force balance acting on the bubbles. The experimental results for

  7. Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

    Science.gov (United States)

    Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

    2016-06-01

    Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

  8. Superficial Velocity Effects on HZ-PAN and AgZ-PAN for Kr/Xe Capture

    Energy Technology Data Exchange (ETDEWEB)

    Welty, Amy Keil [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, Troy Gerry [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, Mitchell Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-04-01

    Nearly all previous testing of HZ-PAN and AgZ-PAN was conducted at the same flow rate in order to maintain consistency among tests. This testing was sufficient for sorbent capacity determinations, but did not ensure that sorbents were capable of functioning under a range of flow regimes. Tests were conducted on both HZ-PAN and AgZ-PAN at superficial velocities between 20 and 700 cm/min. For HZ-PAN, Kr capacity increased from 60 mmol/kg to 110 mmol/kg as superficial velocity increased from 21 to 679 cm/min. Results for AgZ-PAN were similar, with capacity ranging from 72 to 124 mmol/kg over the same range of superficial. These results are promising for scaling up to process flows, demonstrating flexibility to operate in a broad range of superficial velocities while maintaining sorbent capacity. While preparing for superficial velocity testing it was also discovered that AgZ-PAN Xe capacity, previously observed to diminish over time, could be recovered with increased desorption temperature. Further, a substantial Xe capacity increase was observed. Previous room temperature capacities in the range of 22-25 mmol Xe/kg AgZ-PAN were increased to over 60 mmol Xe/kg AgZ-PAN. While this finding has not yet been fully explored to optimize activation and desorption temperatures, it is encouraging.

  9. Detonation velocity in poorly mixed gas mixtures

    Science.gov (United States)

    Prokhorov, E. S.

    2017-10-01

    The technique for computation of the average velocity of plane detonation wave front in poorly mixed mixture of gaseous hydrocarbon fuel and oxygen is proposed. Here it is assumed that along the direction of detonation propagation the chemical composition of the mixture has periodic fluctuations caused, for example, by layered stratification of gas charge. The technique is based on the analysis of functional dependence of ideal (Chapman-Jouget) detonation velocity on mole fraction (with respect to molar concentration) of the fuel. It is shown that the average velocity of detonation can be significantly (by more than 10%) less than the velocity of ideal detonation. The dependence that permits to estimate the degree of mixing of gas mixture basing on the measurements of average detonation velocity is established.

  10. Gas-rise velocities during kicks

    Energy Technology Data Exchange (ETDEWEB)

    White, D.B. (Sedco Forex (FR))

    1991-12-01

    This paper reports on experiments to examine gas migration rates in drilling muds that were performed in a 15-m-long, 200-mm-ID inclinable flow loop where air injection simulates gas entry during a kick. These tests were conducted using a xanthum gum (a common polymer used in drilling fluids) solution to simulate drilling muds as the liquid phase and air as the gas phase. This work represents a significant extension of existing correlations for gas/liquid flows in large pipe diameters with non- Newtonian fluids. Bubbles rise faster in drilling muds than in water despite the increased viscosity. This surprising result is caused by the change in the flow regime, with large slug-type bubbles forming at lower void fractions. The gas velocity is independent of void fraction, thus simplifying flow modeling. Results show that a gas influx will rise faster in a well than previously believed. This has major implications for kick simulation, with gas arriving at the surface earlier than would be expected and the gas outflow rate being higher than would have been predicted. A model of the two-phase gas flow in drilling mud, including the results of this work, has been incorporated into the joint Schlumberger Cambridge Research (SCR)/BP Intl. kick model.

  11. The sound velocity in an equilibrium hadron gas

    OpenAIRE

    Prorok, Dariusz; Turko, Ludwik

    2001-01-01

    We calculate the velocity of sound in an ideal gas of massive hadrons with non-vanishing baryon number. The gas is in thermal and chemical equilibrium. Also we show that the temperature dependence $T(\\tau) \\cong T_{0} \\cdot ({\\tau_{0} \\over \\tau})^{c_{s}^{2}}$ is approximately valid, when the gas expands longitudinally according to the Bjorken law.

  12. Treatment of low-strength wastewater using immobilized biomass in a sequencing batch external loop reactor: influence of the medium superficial velocity on the stability and performance

    Directory of Open Access Journals (Sweden)

    Camargo E.F.M.

    2002-01-01

    Full Text Available An anaerobic sequencing batch bioreactor with external circulation of the liquid phase wherein the biomass was immobilized on a polyurethane foam matrix was analyzed, focussing on the influence of the liquid superficial velocity on the reactor's stability and efficiency. Eight-hour cycles were carried out at 30ºC treating glucose-based synthetic wastewater around 500 mgDQO/L. The performance of the reactor was assessed without circulation and with circulating liquid superficial velocity between 0.034 and 0.188 cm/s. The reactor attained operating stability and a high organic matter removal was achieved when liquid was circulated. A first order model was used to evaluate the influence of the liquid superficial velocity (vS, resulting in an increase in the apparent first order parameter when vS increased from 0.034 to 0.094 cm/s. The parameter value remained unchangeable when 0.188 cm/s was applied, indicating that beyond this value no improvement on liquid mass transfer was observed. Moreover, the necessary time to reach the final removal efficiency decreased when liquid circulation was applied, indicating that a 3-hour cycle could be enough.

  13. Velocity slip of gas mixtures in free jet expansions

    International Nuclear Information System (INIS)

    Cattolica, R.J.; Talbot, L.; Coe, D.

    1976-11-01

    Velocity slip in gas mixtures of argon and helium in axisymmetric free jet expansions has been measured using a grating monochromator together with a computer-controlled Fabry-Perot interferometer to observe the fluorescence excited by an electron beam. The Doppler shift between the fluorescence observed parallel and perpendicular to the centerline of the free jet was used to measure the mean velocity of a particular species along the jet centerline, employing the 4880 A line for argon and the 5016 A line for helium. By alternately tracking the parallel and perpendicular fluorescence, the Doppler shift due to the mean velocity was measured directly with an accuracy of 1 percent. Flow field surveys have been made in the initial acceleration region where the flow becomes hypersonic and in the far field region. The differences between argon and helium mean velocities (velocity slip) are in good agreement with molecular beam data and show a correlation with an inverse Knudsen number

  14. Velocity Dispersion of Ionized Gas and Multiple Supernova Explosions

    Directory of Open Access Journals (Sweden)

    Vasiliev E. O.

    2015-06-01

    Full Text Available We use 3D numerical simulations to study the evolution of the Hα intensity and velocity dispersion for single and multiple supernova (SN explosions. We find that the IHα– σ diagram obtained for simulated gas flows is similar in shape to that observed in dwarf galaxies. We conclude that colliding SN shells with significant difference in age are responsible for high velocity dispersion that reaches up to ≳ 100 km s−1. Such a high velocity dispersion could be hardly obtained for a single SN remnant. Peaks of velocity dispersion in the IHα– σ diagram may correspond to several isolated or merged SN remnants with moderately different ages. Degrading the spatial resolution in the Hα intensity and velocity dispersion maps makes the simulated IHα– σ diagrams close to those observed in dwarf galaxies not only in shape, but also quantitatively.

  15. MAGNETIZED GAS IN THE SMITH HIGH VELOCITY CLOUD

    International Nuclear Information System (INIS)

    Hill, Alex S.; McClure-Griffiths, Naomi M.; Mao, S. A.; Benjamin, Robert A.; Lockman, Felix J.

    2013-01-01

    We report the first detection of magnetic fields associated with the Smith High Velocity Cloud. We use a catalog of Faraday rotation measures toward extragalactic radio sources behind the Smith Cloud, new H I observations from the Robert C. Byrd Green Bank Telescope, and a spectroscopic map of Hα from the Wisconsin H-Alpha Mapper Northern Sky Survey. There are enhancements in rotation measure (RM) of ≈100 rad m –2 which are generally well correlated with decelerated Hα emission. We estimate a lower limit on the line-of-sight component of the field of ≈8 μG along a decelerated filament; this is a lower limit due to our assumptions about the geometry. No RM excess is evident in sightlines dominated by H I or Hα at the velocity of the Smith Cloud. The smooth Hα morphology of the emission at the Smith Cloud velocity suggests photoionization by the Galactic ionizing radiation field as the dominant ionization mechanism, while the filamentary morphology and high (≈1 Rayleigh) Hα intensity of the lower-velocity magnetized ionized gas suggests an ionization process associated with shocks due to interaction with the Galactic interstellar medium. The presence of the magnetic field may contribute to the survival of high velocity clouds like the Smith Cloud as they move from the Galactic halo to the disk. We expect these data to provide a test for magnetohydrodynamic simulations of infalling gas

  16. Gas and particle velocity measurements in an induction plasma

    International Nuclear Information System (INIS)

    Lesinski, J.; Gagne, R.; Boulos, M.I.

    1981-08-01

    Laser doppler anemometry was used for the measurements of the plasma and particle velocity profiles in the coil region of an inductively coupled plasma. Results are reported for a 50 mm ID induction torch operated at atmospheric pressure with argon as the plasma gas. The oscillator frequency was 3 MHz and the power in the coil was varied between 4.6 and 10.5 kW. The gas velocity measurements were made using a fine carbon powder as a tracer (dp approx. = 1 μm). Measurements were also made with larger silicon particles (dp = 33 μm and sigma = 13 μm) centrally injected in the plasma under different operating conditions

  17. Velocities of gas and plasmas from real time holographic interferograms

    International Nuclear Information System (INIS)

    Deason, V.A.; Reynolds, L.D.; McIlwain, M.E.

    1985-01-01

    A truly noninvasive measurement technique for plasma velocity has not been demonstrated. Plasma velocities have been inferred using laser Doppler anemometry or photographic analysis of the position of smoke or small particles. This paper describes an alternate method based on the refractive index change created in a plasma by a gaseous probe material injected into the plasma. This disturbance of the refractive index can be monitored using interferometry. A multipass real time holographic interferometry system was used to follow the changes of the interferometric pattern, and the data was recorded using high speed cinematography. A transparent model of an industrial plasma torch was employed in these studies, and a number of different types of trace gas materials were used to track the plasma flow. Using a combination of multipass interferometry and a laser line absorbing gas, sufficient interferometric sensitivity was obtained to determine plasma velocities in the 100 m/s range. Based on these results, a working plasma torch was constructed. Further studies are planned using this torch and actual plasmas

  18. Caracterización superficial en fase gas y líquida de carbones activados

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo Gutierréz

    2008-05-01

    Full Text Available Se determinó el área superficial de carbones activados obtenidos a partir de cascarilla de café y cáscara de coco, mediante isotermas de adsorción de N2 a 77K. Se compararon los resultados con aquellos obtenidos con un método comúnmente utilizado, el índice de azul de metileno, y se encontró una buena correlación entre las dos áreas determinadas por éste método. Se muestra que los dos métodos permiten realizar un análisis complementario de una superficie porosa./ The superficial area of an activated carbon obtained from coffee husk and coconut shell was determined, by means of isotherms of adsorption of N2 to 77K and the results they area compared with the method of index blue of methylene, finding an good correlation between the two areas determined by this method. This research shows that both methods allow making a complementary analysis of a porous surface.

  19. Velocity limitations in coaxial plasma gun experiments with gas mixtures

    International Nuclear Information System (INIS)

    Axnaes, I.

    1976-04-01

    The velocity limitations found in many crossed field plasma experiments with neutral gas present are studied for binary mixtures of H 2 , He, N 2 O 2 , Ne and Ar. The apparatus used is a coaxial plasma gun with an azimuthal magnetic bias field. The discharge parameters are chosen so that the plasma is weakly ionized. In some of the mixtures it is found that one of the components tends to dominate in the sense that only a small amount (regarding volume) of that component is needed for the discharge to adopt a limiting velocity close to that for the pure component. Thus in a mixture between a heavy and a light component having nearly equal ionization potentials the heavy component dominates. Also if there is a considerable difference in ionization potential between the components, the component with the lowest ionization potential tends to dominate. (author)

  20. The universal sound velocity formula for the strongly interacting unitary Fermi gas

    International Nuclear Information System (INIS)

    Liu Ke; Chen Ji-Sheng

    2011-01-01

    Due to the scale invariance, the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas. For example, the virial theorem between pressure and energy density of the ideal gas P = 2E/3V is still satisfied by the unitary Fermi gas. This paper analyses the sound velocity of unitary Fermi gases with the quasi-linear approximation. For comparison, the sound velocities for the ideal Boltzmann, Bose and Fermi gas are also given. Quite interestingly, the sound velocity formula for the ideal non-interacting gas is found to be satisfied by the unitary Fermi gas in different temperature regions. (general)

  1. The critical ionization velocity mechnism for the case of gas mixture

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1982-08-01

    The theory of the critical ionization velocity mechnisms is discussed. In the case of gas mixture the critical velocity is expected to depend on the ionization cross sections. An analytic approximation is introduced which can be used to set limits on a generalized expression for the critical velocity of gas mixtures. (Author)

  2. Dimethylether: a low velocity, low diffusion drift chamber gas

    International Nuclear Information System (INIS)

    Villa, F.

    1983-01-01

    There are two main motivations to look for a low electron mobility gas: the first is that a low drift velocity relaxes the need to measure drift times with nanosecond (or even subnanosecond) precision; the second is that (in an ideal drift geometry), the capability of resolving two closely spaced tracks depends upon the ratio of electron mobility to ion mobility μ/sub e//μ/sub i/. Since μ/sub i/ is rather constant, the way to separate two tracks is to slow down the electrons. Many other properties are required besides low mobility and low drifting electron temperature: the gas should have a large (> 10 3 ) stable gain; it must be chemically stable and not oxic; it should not attack materials commonly used to fabricate drift chambers, etc. With these requirements in mind, we have tried a few promising (on paper) gases, either pure or in admixture with Argon. One of the gases examined, dimethylether [(CH 3 ) 2 )], has shown interesting characteristics

  3. Gas Velocities Reveal Newly Born Planets in a Disk

    Science.gov (United States)

    Kohler, Susanna

    2018-06-01

    Occasionally, science comes together beautifully for a discovery and sometimes this happens for more than one team at once! Today we explore how two independent collaborations of scientists simultaneously found the very first kinematic evidence for young planets forming in a protoplanetary disk. Though they explored the same disk, the two teams in fact discovered different planets.Evidence for PlanetsALMAs view of the dust in the protoplanetary disk surrounding the young star HD 163296. Todays studies explore not the dust, but the gas of this disk. [ALMA (ESO/NAOJ/NRAO); A. Isella; B. Saxton (NRAO/AUI/NSF)]Over the past three decades, weve detected around 4,000 fully formed exoplanets. Much more elusive, however, are the young planets still in the early stages of formation; only a handful of these have been discovered. More observations of early-stage exoplanets are needed in order to understand how these worlds are born in dusty protoplanetary-disk environments, how they grow their atmospheres, and how they evolve.Recent observations by the Atacama Large Millimeter/submillimeter Array (ALMA) have produced stunning images of protoplanetary disks. The unprecedented resolution of these images reveals substructure in the form of gaps and rings, hinting at the presence of planets that orbit within the disk and clear out their paths as they move. But there are also non-planet mechanisms that could produce such substructure, like grain growth around ice lines, or hydrodynamic instabilities in the disk.How can we definitively determine whether there are nascent planets embedded in these disks? Direct direction of a point source in a dust gap would be a strong confirmation, but now we have the next best thing: kinematic evidence for planets, from the motion of a disks gas.Observations of carbon monoxide line emission at +1km/s from the systemic velocity (left) vs. the outcome of a computer simulation (right) in the Pinte et al. study. A visible kink occurs in the flow

  4. Relation between plasma plume density and gas flow velocity in atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Yambe, Kiyoyuki; Taka, Shogo; Ogura, Kazuo

    2014-01-01

    We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and copper foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. To study the properties of the plasma plume, the plasma plume current is estimated from the difference in currents on the circuit, and the drift velocity is measured using a photodetector. The relation of the plasma plume density n plu , which is estimated from the current and the drift velocity, and the gas flow velocity v gas is examined. It is found that the dependence of the density on the gas flow velocity has relations of n plu ∝ log(v gas ). However, the plasma plume density in the laminar flow is higher than that in the turbulent flow. Consequently, in the laminar flow, the density increases with increasing the gas flow velocity

  5. CFD study of the minimum bubbling velocity of Geldart A particles in gas-fluidized beds

    NARCIS (Netherlands)

    Wang, Junwu; Hoef, van der M.A.; Kuipers, J.A.M.

    2010-01-01

    The minimum bubbling velocity, which demarcates the homogeneous and heterogeneous fluidization regimes, plays a pivotal role in gas fluidization of Geldart A particles. We systematically study the effect of gas and particle properties on the minimum bubbling velocity of Geldart A particles in

  6. Energy Demodulation Algorithm for Flow Velocity Measurement of Oil-Gas-Water Three-Phase Flow

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    2014-01-01

    Full Text Available Flow velocity measurement was an important research of oil-gas-water three-phase flow parameter measurements. In order to satisfy the increasing demands for flow detection technology, the paper presented a gas-liquid phase flow velocity measurement method which was based on energy demodulation algorithm combing with time delay estimation technology. First, a gas-liquid phase separation method of oil-gas-water three-phase flow based on energy demodulation algorithm and blind signal separation technology was proposed. The separation of oil-gas-water three-phase signals which were sampled by conductance sensor performed well, so the gas-phase signal and the liquid-phase signal were obtained. Second, we used the time delay estimation technology to get the delay time of gas-phase signals and liquid-phase signals, respectively, and the gas-phase velocity and the liquid-phase velocity were derived. At last, the experiment was performed at oil-gas-water three-phase flow loop, and the results indicated that the measurement errors met the need of velocity measurement. So it provided a feasible method for gas-liquid phase velocity measurement of the oil-gas-water three-phase flow.

  7. Measurement of gas flow velocities by laser-induced gratings

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B; Stampanoni-Panariello, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Kozlov, A D.N. [General Physics Institute, Moscow (Russian Federation)

    1999-08-01

    Time resolved light scattering from laser-induced electrostrictive gratings was used for the determination of flow velocities in air at room temperature. By measuring the velocity profile across the width of a slit nozzle we demonstrated the high spatial resolution (about 200 mm) of this novel technique. (author) 3 figs., 1 ref.

  8. Natural gas use in treatment of steel surfaces; Utilizacao de gas natural em tratamento de superficies de aco

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, Andre Dias; Machado, Antonio Rogerio; Rocha, Ivan; Azevedo, Jorge; Oshiro, Hugo K.; Konishi, Ricardo; Lehmkuhl, Willian [Companhia de Gas de Santa Catarina (SCGAS), Florianopolis, SC (Brazil); Piazza, Walter [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2011-12-21

    The surface treatments of metals, such as carburizing, rely on processing under high temperature in carbon rich atmospheres. The atmosphere is industrially generated using the partial oxidation of a carbon rich fuel, such as propane, butane or methanol. This article reports a study of the production of a carburizing atmosphere for surface treatment of steel from the partial oxidation of natural gas in a catalytic reactor. The reactor studied was a production size reactor with 300 mm of diameter and 1500 mm of length, packed with alumina supported nickel catalyst. The quality of the carburizing gas was evaluated from its carbon potential of the carburizing gas that was calculated from the concentrations of carbon monoxide (CO), carbon dioxide (CO{sub 2}), oxygen (O{sub 2}) and methane (CH{sub 4}) measured at the reactor's exit. The results indicate that CO concentration is very close to equilibrium, while CO{sub 2} is higher and CH{sub 4} is lower. Examining the reactor, the conclusion was that there was an axial temperature gradient, resulting in lower residence time under the required processing temperature. This resulted in smaller decomposition of CH{sub 4} and smaller production of CO{sub 2}. An equilibrium calculation of carbon potential, expressed as weight percent of carbon in iron, was developed to predict the possible optimizations of mixture composition and reactor temperature for a given required carbon potential. Conclusion: it is possible to generate a carburizing atmosphere under well controlled and repeatable conditions for the carbon potentials required for surface carburizing of steels in industrial processing using natural gas and air mixtures. (author)

  9. Controls on gas transfer velocities in a large river

    Science.gov (United States)

    The emission of biogenic gases from large rivers can be an important component of regional greenhouse gas budgets. However, emission rate estimates are often poorly constrained due to uncertainties in the air-water gas exchange rate. We used the floating chamber method to estim...

  10. Measurement of laminar burning velocities and Markstein lengths of diluted hydrogen-enriched natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Haiyan; Jiao, Qi; Huang, Zuohua; Jiang, Deming [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China)

    2009-01-15

    The laminar flame characteristics of natural gas-hydrogen-air-diluent gas (nitrogen/CO{sub 2}) mixtures were studied in a constant volume combustion bomb at various diluent ratios, hydrogen fractions and equivalence ratios. Both unstretched laminar burning velocity and Markstein length were obtained. The results showed that hydrogen fraction, diluent ratio and equivalence ratio have combined influence on laminar burning velocity and flame instability. The unstretched laminar burning velocity is reduced at a rate that is increased with the increase of the diluent ratio. The reduction effect of CO{sub 2} diluent gas is stronger than that of nitrogen diluent gas. Hydrogen-enriched natural gas with high hydrogen fraction can tolerate more diluent gas than that with low hydrogen fraction. Markstein length can either increase or decrease with the increase of the diluent ratio, depending on the hydrogen fraction of the fuel. (author)

  11. Effects space velocity and gas velocity on DeNOx catalyst with HC reductant; HC tenka NOx kangen shokubai no kukan sokudo oyobi gas ryusoku no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, K.; Tsujimura, K.

    1995-04-20

    Discussions were given on the hydrocarbon added reduction catalyst method to reduce NOx in diesel engine exhaust gas. An experiment was carried out with actual exhaust gas from a diesel engine by using a copper ion exchanged zeolite catalyst that has been coated on a honeycomb type substrate, and using propylene as a reductant. When the catalyst volume was changed with the exhaust gas space velocity kept constant, the NOx conversion ratio decreased as the catalyst length is decreased, and the activity shifted to the lower temperature side. The NOx reduction efficiency increased if the faster the gas flow velocity. On the other hand, if the gas flow velocity is slow, the NOx reduction can be carried out with relatively small amount of the reductant. When the catalyst volume was changed with the passing gas amount kept constant, the NOx conversion ratio decreased largely if the catalyst length is decreased. Further, the NOx reduction characteristics shift to the higher temperature side. In the catalyst length direction, the NOx reduction activity shows a relatively uniform action. However, a detailed observation reveals that the reaction heat in the catalyst is transmitted to the wake improving the activity, hence the further down the flow, the NOx conversion ratio gets higher in efficiency. 5 refs., 5 figs., 3 tabs.

  12. Velocity slip and translational nonequilibrium of ternary gas mixtures in free jet expansions

    International Nuclear Information System (INIS)

    Cattolica, R.J.; Gallagher, R.J.; Anderson, J.B.; Talbot, L.

    1977-05-01

    An aerodynamic isotope separation technique based on the velocity slip between gases in a rarefied flow has been proposed. To evaluate the efficiency of this separation technique, the velocity and translational temperature of the individual species in binary and ternary gas mixtures of argon and neon in helium have been studied in a low density hypersonic free jet. The velocity and temperature of the gas were determined from the Doppler shift and broadening of the fluorescence excited by an electron beam. Velocity slip and translational nonequilibrium were observed over a range of source pressures. A separation factor based on the velocity slip and temperatures was also determined. A comparison of the velocity slip, temperatures, and separation factor with the results of a Monte Carlo simulation of the flow field is presented

  13. Gas density fluctuations in the Perseus Cluster: clumping factor and velocity power spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, I.; Churazov, E.; Arevalo, P.; Schekochihin, A. A.; Allen, S. W.; Fabian, A. C.; Forman, W. R.; Sanders, J. S.; Simionescu, A.; Sunyaev, R.; Vikhlinin, A.; Werner, N.

    2015-05-20

    X-ray surface brightness fluctuations in the core of the Perseus Cluster are analysed, using deep observations with the Chandra observatory. The amplitude of gas density fluctuations on different scales is measured in a set of radial annuli. It varies from 7 to 12 per cent on scales of ~10–30 kpc within radii of 30–220 kpc from the cluster centre. Using a statistical linear relation between the observed amplitude of density fluctuations and predicted velocity, the characteristic velocity of gas motions on each scale is calculated. The typical amplitudes of the velocity outside the central 30 kpc region are 90–140 km s-1 on ~20–30 kpc scales and 70–100 km s-1 on smaller scales ~7–10 kpc. The velocity power spectrum (PS) is consistent with cascade of turbulence and its slope is in a broad agreement with the slope for canonical Kolmogorov turbulence. The gas clumping factor estimated from the PS of the density fluctuations is lower than 7–8 per cent for radii ~30–220 kpc from the centre, leading to a density bias of less than 3–4 per cent in the cluster core. Uncertainties of the analysis are examined and discussed. Future measurements of the gas velocities with the Astro-H, Athena and Smart-X observatories will directly measure the gas density–velocity perturbation relation and further reduce systematic uncertainties in this analysis.

  14. Theoretical analysis of stack gas emission velocity measurement by optical scintillation

    International Nuclear Information System (INIS)

    Yang Yang; Dong Feng-Zhong; Ni Zhi-Bo; Pang Tao; Zeng Zong-Yong; Wu Bian; Zhang Zhi-Rong

    2014-01-01

    Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously. (general)

  15. Influence of the altitude on the burning velocity of the natural gas

    International Nuclear Information System (INIS)

    Arrieta, Andres Amell; Garcia Posada, Jorge Mario; Quilindo Valencia, Arvey; Henao Vallejo, Diego Alberto

    2004-01-01

    By the increasing use of natural gas in cities of Latin America located to high altitude, is necessary to study the effect of the altitude on the combustion, for example the burning velocity. This work is an experimental study of as it changes to the burning velocity with the altitude, being made test in sites with altitude of 40, 550, 1.020, 1.550, 2.040 and 2.550 meters. The result was that the variations are slight

  16. The velocity of missiles generated by the disintegration of gas-pressurized vessels and pipes

    International Nuclear Information System (INIS)

    Baum, M.R.

    1984-01-01

    A theoretical model is developed to describe the velocity of fragments generated when a gas-pressurized vessel disintegrates. The predictions are compared with new and existing experimental data for spherical and cylindrical vessels and are shown to be an improvement over the widely used empirical correlation developed by Moore. It is also shown that, by an appropriate definition of the energy available for doing work on the fragments, the velocity of the fragments from the disintegration of a section of gas pipeline may be predicted by the same model

  17. The velocity of missiles generated by the disintegration of gas-pressurised vessels and pipes

    International Nuclear Information System (INIS)

    Baum, M.R.

    1983-03-01

    A theoretical model is developed to describe the velocity of fragments generated when a gas-pressurised vessel disintegrates. The predictions are compared with new and existing experimental data for spherical and cylindrical vessels and are shown to be an improvement over the widely used empirical correlation developed by Moore. It is also shown that, by an appropriate definition of the energy available for doing work on the fragments, the velocity of the fragments from the disintegration of a section of gas pipeline may be predicted by the same model. (author)

  18. Correlation between centre offsets and gas velocity dispersion of galaxy clusters in cosmological simulations

    Science.gov (United States)

    Li, Ming-Hua; Zhu, Weishan; Zhao, Dong

    2018-05-01

    The gas is the dominant component of baryonic matter in most galaxy groups and clusters. The spatial offsets of gas centre from the halo centre could be an indicator of the dynamical state of cluster. Knowledge of such offsets is important for estimate the uncertainties when using clusters as cosmological probes. In this paper, we study the centre offsets roff between the gas and that of all the matter within halo systems in ΛCDM cosmological hydrodynamic simulations. We focus on two kinds of centre offsets: one is the three-dimensional PB offsets between the gravitational potential minimum of the entire halo and the barycentre of the ICM, and the other is the two-dimensional PX offsets between the potential minimum of the halo and the iterative centroid of the projected synthetic X-ray emission of the halo. Haloes at higher redshifts tend to have larger values of rescaled offsets roff/r200 and larger gas velocity dispersion σ v^gas/σ _{200}. For both types of offsets, we find that the correlation between the rescaled centre offsets roff/r200 and the rescaled 3D gas velocity dispersion, σ _v^gas/σ _{200} can be approximately described by a quadratic function as r_{off}/r_{200} ∝ (σ v^gas/σ _{200} - k_2)2. A Bayesian analysis with MCMC method is employed to estimate the model parameters. Dependence of the correlation relation on redshifts and the gas mass fraction are also investigated.

  19. Measurements of gas velocity in supersonic flow using a laser beam

    International Nuclear Information System (INIS)

    Airoldi, V.J.T.; Santos, R. dos

    1982-01-01

    A study of measurements of supersonic velocities in a wind tunnel using a laser beam was performed. Techniques using lasers are most suitable because they do not disturb the gas flow. This work presents the technique entitled as fringe technique. It works using interference patterns due to two perpendicular laser beams crossing the sample (i.e. the gas flow). Experimental results are compared with other usual techniques. (R.S.)

  20. Modeling of flowing gas diode pumped alkali lasers: dependence of the operation on the gas velocity and on the nature of the buffer gas.

    Science.gov (United States)

    Barmashenko, B D; Rosenwaks, S

    2012-09-01

    A simple, semi-analytical model of flowing gas diode pumped alkali lasers (DPALs) is presented. The model takes into account the rise of temperature in the lasing medium with increasing pump power, resulting in decreasing pump absorption and slope efficiency. The model predicts the dependence of power on the flow velocity in flowing gas DPALs and checks the effect of using a buffer gas with high molar heat capacity and large relaxation rate constant between the 2P3/2 and 2P1/2 fine-structure levels of the alkali atom. It is found that the power strongly increases with flow velocity and that by replacing, e.g., ethane by propane as a buffer gas the power may be further increased by up to 30%. Eight kilowatt is achievable for 20 kW pump at flow velocity of 20  m/s.

  1. The influence of liquid-gas velocity ratio on the noise of the cooling tower

    Science.gov (United States)

    Yang, Bin; Liu, Xuanzuo; Chen, Chi; Zhao, Zhouli; Song, Jinchun

    2018-05-01

    The noise from the cooling tower has a great influence on psychological performance of human beings. The cooling tower noise mainly consists of fan noise, falling water noise and mechanical noise. This thesis used DES turbulence model with FH-W model to simulate the flow and sound pressure field in cooling tower based on CFD software FLUENT and analyzed the influence of different kinds noise, which affected by diverse factors, on the cooling tower noise. It can be concluded that the addition of cooling water can reduce the turbulence and vortex noise of the rotor fluid field in the cooling tower at some extent, but increase the impact noise of the liquid-gas two phase. In general, the cooling tower noise decreases with the velocity ratio of liquid to gas increasing, and reaches the lowest when the velocity ratio of liquid to gas is close to l.

  2. Water droplet deformation under the motion in gas area with subsonic velocities

    Directory of Open Access Journals (Sweden)

    Kuibin Pavel A.

    2015-01-01

    Full Text Available The experimental investigation of water droplet deformation (characteristic dimensions 3 ÷ 6 mm when moving through the gas area (air with 1÷ 5 m/s velocities was carried out. The high-speed (delay time between the frames is less than 100 ns tools of cross-correlation videorecording were used. A cyclic change nature of the droplet shapes (from close to spherical to conditionally ellipsoidal was found. The characteristic times of “deformation cycles” and the maximal deviations of droplet dimensions relative to initial dimensions were determined. The influence of droplet velocities and its dimensions on the deformation characteristics was determined.

  3. Automatic discrimination of bubbles and slugs in two-phase gas-liquid flow and measurement of the respective velocities

    International Nuclear Information System (INIS)

    Fitremann, J.M.; Guilpin, C.; Postaire, J.

    1976-01-01

    The measurement of the interface velocity in a two-phase gas-liquid flow is a difficult problem, owing to the dispersion of the velocity components of individual bubbles, gas-slugs, droplets, waves, etc. An entirely automatic method is presented, it gives the velocity of slugs and bubbles independently, by discrimination of local phase probe signals into a 'slug' signal and a 'bubble' signal feeding a shape-recognition program. Both discriminated void fractions are also calculated by the apparatus [fr

  4. Measurement of Gas Velocities in the Presence of Solids in the Riser of a Cold Flow Circulating Fluidized Bed

    International Nuclear Information System (INIS)

    Spenik, J.; Ludlow, J.C.; Compston, R.; Breault, R.W.

    2007-01-01

    The local gas velocity and the intensity of the gas turbulence in a gas/solid flow are a required measurement in validating the gas and solids flow structure predicted by computational fluid dynamic (CFD) models in fluid bed and transport reactors. The high concentration and velocities of solids, however, make the use of traditional gas velocity measurement devices such as pitot tubes, hot wire anemometers and other such devices difficult. A method of determining these velocities has been devised at the National Energy Technology Laboratory employing tracer gas. The technique developed measures the time average local axial velocity gas component of a gas/solid flow using an injected tracer gas which induces changes in the heat transfer characteristics of the gas mixture. A small amount of helium is injected upstream a known distance from a self-heated thermistor. The thermistor, protected from the solids by means of a filter, is exposed to gases that are continuously extracted from the flow. Changes in the convective heat transfer characteristics of the gas are indicated by voltage variations across a Wheatstone bridge. When pulsed injections of helium are introduced to the riser flow the change in convective heat transfer coefficient of the gas can be rapidly and accurately determined with this instrument. By knowing the separation distance between the helium injection point and the thermistor extraction location as well as the time delay between injection and detection, the gas velocity can easily be calculated. Variations in the measured gas velocities also allow the turbulence intensity of the gas to be estimated

  5. Drift velocity studies at a time projection chamber for various water contents in the gas mixture

    International Nuclear Information System (INIS)

    Stoever, F.W.

    2007-03-01

    For the answer of different open questions in high energy physics the construction of a linear e + e - collider with a c. m. energy of up to one TeV is prepared. With this is connected a comprehensive development on detectors, which must satisfy the requirements of the planned experiments. For the track chamber a TPC is considered. Hereby it deals with a gas-based concept, which has already been proved in past experiments and which is at time further developed by means of test chambers. The composition of the gas mixtureplays hereby an important role. Impurities of the gas mixture, especially by oxygen and water from the ambient air are a fact, which occurs every time in the development phase and can scarcely be avoided. From this arose the motivation to study directly the effects of this impurities. The object of the present thesis are correlations between drift velocity and water content in the chamber gas of a TPC

  6. Correlations of drift velocity for gas-liquid two-phase flow in rod bundle

    International Nuclear Information System (INIS)

    Kataoka, Isao; Matsuura, Keizo; Serizawa, Akimi

    2004-01-01

    A new correlation was developed for the drift velocity for low inlet liquid flux in rod bundle. Based on authors' previous analysis of drift velocity for large diameter pipe, an analysis was made on the drift velocity in rod bundle. It is assumed that the large bubble of which size is several subchannel diameter behaves as slug bubble. Under this assumption, it becomes very important how to define equivalent diameter for rod bundle. In view of physical consideration of slug bubble behavior and previous analysis, an equivalent diameter based on the wetted perimeter was found to be most appropriate. Using this equivalent diameter, experimental data of drift velocity in rod bundle were correlated with dimensional analysis. It was found out that for small diameter (dimensionless diameter less than 48) drift velocity increased with square root of diameter which is same dependency of ordinary slug flow correlation. For larger diameter (dimensionless diameter is more than 48), drift velocity is almost constant and same as that of dimensionless diameter of 48. The physical meaning of this result was considered to be the instability of interface of large slug bubble. The density ratio between gas and liquid and viscosity of liquid phase were found to be the main parameters which affect the drift velocity. This is physically reasonable because density ratio is related to the buoyancy force and liquid viscosity is related to shear force near solid wall. The experimental data were correlated by density ratio and dimensionless liquid viscosity. The obtained dimensionless correlation for the drift velocity in rod bundle successfully correlated experimental data for various rod bundles (equivalent diameters), pressures, liquid fluxes etc. It is also consistent with the drift flux correlation for round tube. (author)

  7. Development of high velocity gas gun with a new trigger system-numerical analysis

    Science.gov (United States)

    Husin, Z.; Homma, H.

    2018-02-01

    In development of high performance armor vests, we need to carry out well controlled experiments using bullet speed of more than 900 m/sec. After reviewing trigger systems used for high velocity gas guns, this research intends to develop a new trigger system, which can realize precise and reproducible impact tests at impact velocity of more than 900 m/sec. A new trigger system developed here is called a projectile trap. A projectile trap is placed between a reservoir and a barrel. A projectile trap has two functions of a sealing disk and triggering. Polyamidimide is selected for the trap material and dimensions of the projectile trap are determined by numerical analysis for several levels of launching pressure to change the projectile velocity. Numerical analysis results show that projectile trap designed here can operate reasonably and stresses caused during launching operation are less than material strength. It means a projectile trap can be reused for the next shooting.

  8. Fluctuating ideal-gas lattice Boltzmann method with fluctuation dissipation theorem for nonvanishing velocities.

    Science.gov (United States)

    Kaehler, G; Wagner, A J

    2013-06-01

    Current implementations of fluctuating ideal-gas descriptions with the lattice Boltzmann methods are based on a fluctuation dissipation theorem, which, while greatly simplifying the implementation, strictly holds only for zero mean velocity and small fluctuations. We show how to derive the fluctuation dissipation theorem for all k, which was done only for k=0 in previous derivations. The consistent derivation requires, in principle, locally velocity-dependent multirelaxation time transforms. Such an implementation is computationally prohibitively expensive but, with a small computational trick, it is feasible to reproduce the correct FDT without overhead in computation time. It is then shown that the previous standard implementations perform poorly for non vanishing mean velocity as indicated by violations of Galilean invariance of measured structure factors. Results obtained with the method introduced here show a significant reduction of the Galilean invariance violations.

  9. Hydromagnetic Rayleigh endash Taylor instability in high-velocity gas-puff implosions

    International Nuclear Information System (INIS)

    Roderick, N.F.; Peterkin, R.E. Jr.; Hussey, T.W.; Spielman, R.B.; Douglas, M.R.; Deeney, C.

    1998-01-01

    Experiments using the Saturn pulsed power generator have produced high-velocity z-pinch plasma implosions with velocities over 100 cm/μs using both annular and uniform-fill gas injection initial conditions. Both types of implosion show evidence of the hydromagnetic Rayleigh endash Taylor instability with the uniform-fill plasmas producing a more spatially uniform pinch. Two-dimensional magnetohydrodynamic simulations including unsteady flow of gas from a nozzle into the diode region have been used to investigate these implosions. The instability develops from the nonuniform gas flow field that forms as the gas expands from the injection nozzle. Instability growth is limited to the narrow unstable region of the current sheath. For the annular puff the unstable region breaks through the inner edge of the annulus increasing nonlinear growth as mass ejected from the bubble regions is not replenished by accretion. This higher growth leads to bubble thinning and disruption producing greater nonuniformity at pinch for the annular puff. The uniform puff provides gas to replenish bubble mass loss until just before pinch resulting in less bubble thinning and a more uniform pinch. copyright 1998 American Institute of Physics

  10. Magnetic resonance velocity imaging of liquid and gas two-phase flow in packed beds.

    Science.gov (United States)

    Sankey, M H; Holland, D J; Sederman, A J; Gladden, L F

    2009-02-01

    Single-phase liquid flow in porous media such as bead packs and model fixed bed reactors has been well studied by MRI. To some extent this early work represents the necessary preliminary research to address the more challenging problem of two-phase flow of gas and liquid within these systems. In this paper, we present images of both the gas and liquid velocities during stable liquid-gas flow of water and SF(6) within a packing of 5mm spheres contained within columns of diameter 40 and 27 mm; images being acquired using (1)H and (19)F observation for the water and SF(6), respectively. Liquid and gas flow rates calculated from the velocity images are in agreement with macroscopic flow rate measurements to within 7% and 5%, respectively. In addition to the information obtained directly from these images, the ability to measure liquid and gas flow fields within the same sample environment will enable us to explore the validity of assumptions used in numerical modelling of two-phase flows.

  11. High velocity molecular gas near Herbig-Haro objects HH 7--11

    International Nuclear Information System (INIS)

    Snell, R.L.; Edwards, S.

    1981-01-01

    Observations of the J = 2-1 and J = 1-0 transitions of 12 CO and 13 CO reveal the presence of high velocity molecular gas associated with a low luminosity infrared source in the vicinity of the Herbig-Haro objects HH 7--11. The blueshifted and redshifted wings show peak intensities spatially separated by 1X5 (0.2 pc), suggesting an energetic bipolar outflow of gas from a young low mass star. The mass loss rate implied by these observations is 8 x 10 -6 M/sub sun/ yr -1

  12. Electron drift velocities of Ar-CO2-CF4 gas mixtures

    International Nuclear Information System (INIS)

    Markeloff, R.

    1994-11-01

    The muon spectrometer for the D0 experiment at Fermi National Accelerator Laboratory uses proportional drift tubes filled with an Ar-CO 2 -CF 4 gas mixture. Measurements of drift velocity as a function of electric field magnitude for 90%-5%-5% and 90%-4%-6% Ar-CO 2 -CF 4 mixtures are presented, and our operational experiences with these gases at D0 is discussed

  13. A simple measurement method of molecular relaxation in a gas by reconstructing acoustic velocity dispersion

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Zhang, Xiangqun; Li, Caiyun

    2018-01-01

    Recently, a decomposition method of acoustic relaxation absorption spectra was used to capture the entire molecular multimode relaxation process of gas. In this method, the acoustic attenuation and phase velocity were measured jointly based on the relaxation absorption spectra. However, fast and accurate measurements of the acoustic attenuation remain challenging. In this paper, we present a method of capturing the molecular relaxation process by only measuring acoustic velocity, without the necessity of obtaining acoustic absorption. The method is based on the fact that the frequency-dependent velocity dispersion of a multi-relaxation process in a gas is the serial connection of the dispersions of interior single-relaxation processes. Thus, one can capture the relaxation times and relaxation strengths of N decomposed single-relaxation dispersions to reconstruct the entire multi-relaxation dispersion using the measurements of acoustic velocity at 2N  +  1 frequencies. The reconstructed dispersion spectra are in good agreement with experimental data for various gases and mixtures. The simulations also demonstrate the robustness of our reconstructive method.

  14. Stability aspects of plasmas penetrated by neutral gas with respect to velocity driven modes

    International Nuclear Information System (INIS)

    Ohlsson, D.

    1978-08-01

    A study of the stability properties of dense partially ionized plasmas immersed in strong magnetic fields with respect to velocity driven modes are presented. First we consider modes driven by mass motion perpendicular to the lines of force and the unperturbed density and temperature gradients. The presence of a third fluid, neutral gas, gives under certain conditions rise to unstable modes. This type of instability arises independently or whether the applied electric field transverse to the lines of force, driving the mass motion, being parallel or antiparallel to the unperturbed density and temperature gradient. The presence of neutral gas also corresponds to stabilizing effects which, in certain parameter regions, result in a quenching of this instability. It is shown that modes driven by velocity shear perpendicular to the lines of force are effectively stabilized by viscous and resistive effects. These effects are in certain parameter ranges strongly enhanced on account of plasma-neutral gas interaction effects. In collisionless plasmas, modes driven by velocity shear parallel to the lines of force are stabilized by compressibility effects parallel to the magnetic field and by finite Larmor radius effects. (author)

  15. Renormalization of Fermi Velocity in a Composite Two Dimensional Electron Gas

    Science.gov (United States)

    Weger, M.; Burlachkov, L.

    We calculate the self-energy Σ(k, ω) of an electron gas with a Coulomb interaction in a composite 2D system, consisting of metallic layers of thickness d ≳ a0, where a0 = ħ2ɛ1/me2 is the Bohr radius, separated by layers with a dielectric constant ɛ2 and a lattice constant c perpendicular to the planes. The behavior of the electron gas is determined by the dimensionless parameters kFa0 and kFc ɛ2/ɛ1. We find that when ɛ2/ɛ1 is large (≈5 or more), the velocity v(k) becomes strongly k-dependent near kF, and v(kF) is enhanced by a factor of 5-10. This behavior is similar to the one found by Lindhard in 1954 for an unscreened electron gas; however here we take screening into account. The peak in v(k) is very sharp (δk/kF is a few percent) and becomes sharper as ɛ2/ɛ1 increases. This velocity renormalization has dramatic effects on the transport properties; the conductivity at low T increases like the square of the velocity renormalization and the resistivity due to elastic scattering becomes temperature dependent, increasing approximately linearly with T. For scattering by phonons, ρ ∝ T2. Preliminary measurements suggest an increase in vk in YBCO very close to kF.

  16. The influence of gas phase velocity fluctuations on primary atomization and droplet deformation

    Science.gov (United States)

    Kourmatzis, A.; Masri, A. R.

    2014-02-01

    The effects of grid-generated velocity fluctuations on the primary atomization and subsequent droplet deformation of a range of laminar liquid jets are examined using microscopic high-speed backlit imaging of the break-up zone and laser Doppler anemometry of the gas phase separately. This is done for fixed gas mean flow conditions in a miniature wind tunnel experiment utilizing a selection of fuels, turbulence-generating grids and two syringe sizes. The constant mean flow allows for an isolated study of velocity fluctuation effects on primary atomization in a close approximation to homogeneous decaying turbulence. The qualitative morphology of the primary break-up region is examined over a range of turbulence intensities, and spectral analysis is performed in order to ascertain the break-up frequency which, for a case of no grid, compares well with the existing literature. The addition of velocity fluctuations tends to randomize the break-up process. Slightly downstream of the break-up region, image processing is conducted in order to extract a number of metrics, which do not depend on droplet sphericity, and these include droplet aspect ratio and orientation, the latter quantity being somewhat unconventional in spray characterization. A turbulent Weber number which takes into account gas phase fluctuations is utilized to characterize the resulting droplet shapes, in addition to a mean Weber number . Above a a clear positive relationship exists between the mean aspect ratio of droplets and the turbulent Weber number where is varied by altering all relevant variables including the velocity root mean square, the initial droplet diameter, the surface tension and the density.

  17. An evaluation of gas transfer velocity parameterizations during natural convection using DNS

    Science.gov (United States)

    Fredriksson, Sam T.; Arneborg, Lars; Nilsson, Hâkan; Zhang, Qi; Handler, Robert A.

    2016-02-01

    Direct numerical simulations (DNS) of free surface flows driven by natural convection are used to evaluate different methods of estimating air-water gas exchange at no-wind conditions. These methods estimate the transfer velocity as a function of either the horizontal flow divergence at the surface, the turbulent kinetic energy dissipation beneath the surface, the heat flux through the surface, or the wind speed above the surface. The gas transfer is modeled via a passive scalar. The Schmidt number dependence is studied for Schmidt numbers of 7, 150 and 600. The methods using divergence, dissipation and heat flux estimate the transfer velocity well for a range of varying surface heat flux values, and domain depths. The two evaluated empirical methods using wind (in the limit of no wind) give reasonable estimates of the transfer velocity, depending however on the surface heat flux and surfactant saturation. The transfer velocity is shown to be well represented by the expression, ks=A |Bν|1/4 Sc-n, where A is a constant, B is the buoyancy flux, ν is the kinematic viscosity, Sc is the Schmidt number, and the exponent n depends on the water surface characteristics. The results suggest that A=0.39 and n≈1/2 and n≈2/3 for slip and no-slip boundary conditions at the surface, respectively. It is further shown that slip and no-slip boundary conditions predict the heat transfer velocity corresponding to the limits of clean and highly surfactant contaminated surfaces, respectively. This article was corrected on 22 MAR 2016. See the end of the full text for details.

  18. Longitudinal dispersion coefficient depending on superficial velocity of hydrogen isotopes flowing in column packed with zeolite pellets at 77.4 K

    Energy Technology Data Exchange (ETDEWEB)

    Kotoh, K. [Faculty of Engineering, Kyushu University, Nishi-ku, Fukuoka (Japan); Graduate School of Engineering, Kyushu University, Nishi-ku, Fukuoka (Japan); Kubo, K.; Takashima, S.; Moriyama, S.T. [Graduate School of Engineering, Kyushu University, Nishi-ku, Fukuoka (Japan); Tanaka, M. [National Institute for Fusion Science, Oroshi-cho, Toki, Gifu (Japan); Sugiyama, T. [Faculty of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya (Japan)

    2015-03-15

    Authors have been developing a cryogenic pressure swing adsorption system for hydrogen isotope separation. In the problem of its design and operation, it is necessary to predict the concentration profiles developing in packed beds of adsorbent pellets. The profiling is affected by the longitudinal dispersion of gas flowing in packed beds, in addition to the mass transfer resistance in porous media of adsorbent pellets. In this work, an equation is derived for estimating the packed-bed dispersion coefficient of hydrogen isotopes, by analyzing the breakthrough curves of trace D{sub 2} or HD replacing H{sub 2} adsorbed in synthetic zeolite particles packed columns at the liquefied nitrogen temperature 77.4 K. Since specialized for hydrogen isotopes, this equation can be considered to estimate the dispersion coefficients more reliable for the cryogenic hydrogen isotope adsorption process, than the existing equations. (authors)

  19. Statistics of surface divergence and their relation to air-water gas transfer velocity

    Science.gov (United States)

    Asher, William E.; Liang, Hanzhuang; Zappa, Christopher J.; Loewen, Mark R.; Mukto, Moniz A.; Litchendorf, Trina M.; Jessup, Andrew T.

    2012-05-01

    Air-sea gas fluxes are generally defined in terms of the air/water concentration difference of the gas and the gas transfer velocity,kL. Because it is difficult to measure kLin the ocean, it is often parameterized using more easily measured physical properties. Surface divergence theory suggests that infrared (IR) images of the water surface, which contain information concerning the movement of water very near the air-water interface, might be used to estimatekL. Therefore, a series of experiments testing whether IR imagery could provide a convenient means for estimating the surface divergence applicable to air-sea exchange were conducted in a synthetic jet array tank embedded in a wind tunnel. Gas transfer velocities were measured as a function of wind stress and mechanically generated turbulence; laser-induced fluorescence was used to measure the concentration of carbon dioxide in the top 300 μm of the water surface; IR imagery was used to measure the spatial and temporal distribution of the aqueous skin temperature; and particle image velocimetry was used to measure turbulence at a depth of 1 cm below the air-water interface. It is shown that an estimate of the surface divergence for both wind-shear driven turbulence and mechanically generated turbulence can be derived from the surface skin temperature. The estimates derived from the IR images are compared to velocity field divergences measured by the PIV and to independent estimates of the divergence made using the laser-induced fluorescence data. Divergence is shown to scale withkLvalues measured using gaseous tracers as predicted by conceptual models for both wind-driven and mechanically generated turbulence.

  20. Design of a Two-Stage Light Gas Gun for Muzzle Velocities of 10 - 11 kms

    Science.gov (United States)

    Bogdanoff, David W.

    2016-01-01

    Space debris poses a major risk to spacecraft. In low earth orbit, impact velocities can be 10 11 kms and as high as 15 kms. For debris shield design, it would be desirable to be able to launch controlled shape projectiles to these velocities. The design of the proposed 10 11 kmsec gun uses, as a starting point, the Ames 1.280.22 two stage gun, which has achieved muzzle velocities of 10 11.3 kmsec. That gun is scaled up to a 0.3125 launch tube diameter. The gun is then optimized with respect to maximum pressures by varying the pump tube length to diameter ratio (LD), the piston mass and the hydrogen pressure. A pump tube LD of 36.4 is selected giving the best overall performance. Piezometric ratios for the optimized guns are found to be 2.3, much more favorable than for more traditional two stage light gas guns, which range from 4 to 6. The maximum powder chamber pressures are 20 to 30 ksi. To reduce maximum pressures, the desirable range of the included angle of the cone of the high pressure coupling is found to be 7.3 to 14.6 degrees. Lowering the break valve rupture pressure is found to lower the maximum projectile base pressure, but to raise the maximum gun pressure. For the optimized gun with a pump tube LD of 36.4, increasing the muzzle velocity by decreasing the projectile mass and increasing the powder loads is studied. It appears that saboted spheres could be launched to 10.25 and possibly as high as 10.7 10.8 kmsec, and that disc-like plastic models could be launched to 11.05 kms. The use of a tantalum liner to greatly reduce bore erosion and increase muzzle velocity is discussed. With a tantalum liner, CFD code calculations predict muzzle velocities as high as 12 to 13 kms.

  1. Studying the instantaneous velocity field in gas-sheared liquid films in a horizontal duct

    Science.gov (United States)

    Vasques, Joao; Tokarev, Mikhail; Cherdantsev, Andrey; Hann, David; Hewakandamby, Buddhika; Azzopardi, Barry

    2016-11-01

    In annular flow, the experimental validation of the basic assumptions on the liquid velocity profile is vital for developing theoretical models of the flow. However, the study of local velocity of liquid in gas-sheared films has proven to be a challenging task due to the highly curved and disturbed moving interface of the phases, small scale of the area of interrogation, high velocity gradients and irregular character of the flow. This study reports on different optical configurations and interface-tracking methods employed in a horizontal duct in order to obtain high-resolution particle image velocimetry (PIV) data in such types of complex flows. The experimental envelope includes successful measurements in 2D and 3D waves regimes, up to the disturbance wave regime. Preliminary data show the presence of complex structures in the liquid phase, which includes re-circulation areas below the liquid interface due to the gas-shearing action, together with non-uniform transverse movements of the liquid phase close to the wall due to the presence of 3D waves at the interface. With the aid of the moving interface-tracking, PIV, time-resolved particle-tracking velocimetry and vorticity measurements were performed.

  2. Self-determined shapes and velocities of giant near-zero drag gas cavities

    KAUST Repository

    Vakarelski, Ivan Uriev

    2017-09-09

    Minimizing the retarding force on a solid moving in liquid is the canonical problem in the quest for energy saving by friction and drag reduction. For an ideal object that cannot sustain any shear stress on its surface, theory predicts that drag force will fall to zero as its speed becomes large. However, experimental verification of this prediction has been challenging. We report the construction of a class of self-determined streamlined structures with this free-slip surface, made up of a teardrop-shaped giant gas cavity that completely encloses a metal sphere. This stable gas cavity is formed around the sphere as it plunges at a sufficiently high speed into the liquid in a deep tank, provided that the sphere is either heated initially to above the Leidenfrost temperature of the liquid or rendered superhydrophobic in water at room temperature. These sphere-in-cavity structures have residual drag coefficients that are typically less than Embedded Image those of solid objects of the same dimensions, which indicates that they experienced very small drag forces. The self-determined shapes of the gas cavities are shown to be consistent with the Bernoulli equation of potential flow applied on the cavity surface. The cavity fall velocity is not arbitrary but is uniquely predicted by the sphere density and cavity volume, so larger cavities have higher characteristic velocities.

  3. Velocity statistics for interacting edge dislocations in one dimension from Dyson's Coulomb gas model.

    Science.gov (United States)

    Jafarpour, Farshid; Angheluta, Luiza; Goldenfeld, Nigel

    2013-10-01

    The dynamics of edge dislocations with parallel Burgers vectors, moving in the same slip plane, is mapped onto Dyson's model of a two-dimensional Coulomb gas confined in one dimension. We show that the tail distribution of the velocity of dislocations is power law in form, as a consequence of the pair interaction of nearest neighbors in one dimension. In two dimensions, we show the presence of a pairing phase transition in a system of interacting dislocations with parallel Burgers vectors. The scaling exponent of the velocity distribution at effective temperatures well below this pairing transition temperature can be derived from the nearest-neighbor interaction, while near the transition temperature, the distribution deviates from the form predicted by the nearest-neighbor interaction, suggesting the presence of collective effects.

  4. Wave Attenuation and Gas Exchange Velocity in Marginal Sea Ice Zone

    Science.gov (United States)

    Bigdeli, A.; Hara, T.; Loose, B.; Nguyen, A. T.

    2018-03-01

    The gas transfer velocity in marginal sea ice zones exerts a strong control on the input of anthropogenic gases into the ocean interior. In this study, a sea state-dependent gas exchange parametric model is developed based on the turbulent kinetic energy dissipation rate. The model is tuned to match the conventional gas exchange parametrization in fetch-unlimited, fully developed seas. Next, fetch limitation is introduced in the model and results are compared to fetch limited experiments in lakes, showing that the model captures the effects of finite fetch on gas exchange with good fidelity. Having validated the results in fetch limited waters such as lakes, the model is next applied in sea ice zones using an empirical relation between the sea ice cover and the effective fetch, while accounting for the sea ice motion effect that is unique to sea ice zones. The model results compare favorably with the available field measurements. Applying this parametric model to a regional Arctic numerical model, it is shown that, under the present conditions, gas flux into the Arctic Ocean may be overestimated by 10% if a conventional parameterization is used.

  5. A Novel Method for Determining the Gas Transfer Velocity of Carbon Dioxide in Streams

    Science.gov (United States)

    McDowell, M. J.; Johnson, M. S.

    2016-12-01

    Characterization of the global carbon cycle relies on the accurate quantification of carbon fluxes into and out of natural and human-dominated ecosystems. Among these fluxes, carbon dioxide (CO2) evasion from surface water has received increasing attention in recent years. However, limitations of current methods, including determination of the gas transfer velocity (k), compromise our ability to evaluate the significance of CO2 fluxes between freshwater systems and the atmosphere. We developed an automated method to determine gas transfer velocities of CO2 (kCO2), and tested it under a range of flow conditions for a first-order stream of a headwater catchment in southwestern British Columbia, Canada. Our method uses continuous in situ measurements of CO2 concentrations using two non-dispersive infrared (NDIR) sensors enclosed in water impermeable, gas permeable membranes (Johnson et al., 2010) downstream from a gas diffuser. CO2 was injected into the stream at regular intervals via a compressed gas tank connected to the diffuser. CO2 injections were controlled by a datalogger at fixed time intervals and in response to storm-induced changes in streamflow. Following the injection, differences in CO2 concentrations at known distances downstream from the diffuser relative to pre-injection baseline levels allowed us to calculate kCO2. Here we present relationships between kCO2 and hydro-geomorphologic (flow velocity, streambed slope, stream width, stream depth), atmospheric (wind speed and direction), and water quality (stream temperature, pH, electrical conductivity) variables. This method has advantages of being automatable and field-deployable, and it does not require supplemental gas chromatography, as is the case for propane injections typically used to determine k. The dataset presented suggests the potential role of this method to further elucidate the role that CO2 fluxes from headwater streams play in the global carbon cycle. Johnson, M. S., Billett, M. F

  6. On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

    Science.gov (United States)

    Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.

    2016-05-01

    The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature- and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2, and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of nonseasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer-term flux variability.

  7. DEPOSITION OF FISSION PRODUCTS FROM HELIUM GAS FLOWING AT HIGH VELOCITIES

    Energy Technology Data Exchange (ETDEWEB)

    Abriss, A.; Ewing, R. A.; Sunderman, D. N.

    1963-11-15

    From American Nuclear Society Meeting, New York, Nov. 1963. Out-of- pile experiments simulating gas cooled reactor flow and temperature conditions were made to correlate by both empirical and theoretical considerations such parameters as Reynolds numbers, velocity, surface conditions, materials of construction, geometry, particulate matter, and fission product diffusion coefficients. It was concluded that all regions of flow disturbance are areas of buildup of activity. No selectivity in deposition among the elements studied, with the exception of I, Te, and Cs, was found. Relative abundances to each other of less volatile isotopes remained constant throughout any particular experiment. Data are tabulated. (P.C.H.)

  8. On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

    OpenAIRE

    Couldrey, Matthew; Oliver, Kevin; Yool, Andrew; Halloran, Paul; Achterberg, Eric

    2016-01-01

    The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual...

  9. Surface shear stress dependence of gas transfer velocity parameterizations using DNS

    Science.gov (United States)

    Fredriksson, S. T.; Arneborg, L.; Nilsson, H.; Handler, R. A.

    2016-10-01

    Air-water gas-exchange is studied in direct numerical simulations (DNS) of free-surface flows driven by natural convection and weak winds. The wind is modeled as a constant surface-shear-stress and the gas-transfer is modeled via a passive scalar. The simulations are characterized via a Richardson number Ri=Bν/u*4 where B, ν, and u* are the buoyancy flux, kinematic viscosity, and friction velocity respectively. The simulations comprise 0Ric or kg=AShearu*Sc-n, Ri

  10. Efectos de la instalación de un gasoducto sobre algunas propiedades del suelo superficial y la cobertura vegetal en el NE de Chubut Gas-pipeline installation effects on superficial soil properties and vegetation cover in Northeastern Chubut

    Directory of Open Access Journals (Sweden)

    Esteban Kowaljow

    2008-07-01

    Full Text Available En este trabajo describimos el impacto del tendido de un gasoducto y de la reposición parcial del material removido, sobre algunas propiedades físicas y químicas del suelo y sobre la cobertura vegetal en tres sitios ecológicos del nordeste de Chubut. En cada sitio se identificaron 4 zonas diferentes: zona 1, faja desmontada y compactada por el tránsito de maquinaria pesada; zona 2, faja desmontada, con posterior reposición del suelo y la vegetación removidos; y otras dos zonas correspondientes a la estepa adyacente no disturbada: montículos asociados a arbustos y espacios entre montículos. Los mayores valores de densidad aparente se encontraron en los suelos de la zona 1 y en los del entremontículo (1,43 Mg m-3. La resistencia a la penetración fue significativamente mayor en las zonas 1 y 2, ambas zonas presentaron valores de resistencia a la penetración superiores a 1 MPa. La tasa de infiltración fue mucho mayor en el montículo (261 mm h-1 que en el resto de las zonas. La velocidad de infiltración de la zona 2 (85 mm h-1 fue mayor a la de la zona 1 (35 mm h-1 y el entremontículo (50 mm h-1. Los contenidos de carbono orgánico y nitrógeno de los suelos de las zonas 1 y 2 fueron similares a los del entremontículo y significativamente inferiores a los del montículo, excepto en la zona 2 de uno de los sitios ecológicos. La remoción de la vegetación y el suelo superficial, y el posterior tránsito de maquinaria pesada durante la instalación del gasoducto produjeron un fuerte impacto sobre las propiedades físicas del suelo. La mayor limitación de los suelos disturbados fue su baja capacidad para incorporar agua, derivada principalmente de su elevada compactación y baja porosidad, lo que explicaría en parte la lenta recuperación de la cobertura vegetal en la zona 1. En ninguno de los tres sitios estudiados, la reposición del material removido por la actividad del desmonte significó una medida de recuperación eficaz

  11. Visualization of velocity field and phase distribution in gas-liquid two-phase flow by NMR imaging

    International Nuclear Information System (INIS)

    Matsui, G.; Monji, H.; Obata, J.

    2004-01-01

    NMR imaging has been applied in the field of fluid mechanics, mainly single phase flow, to visualize the instantaneous flow velocity field. In the present study, NMR imaging was used to visualize simultaneously both the instantaneous phase structure and velocity field of gas-liquid two-phase flow. Two methods of NMR imaging were applied. One is useful to visualize both the one component of liquid velocity and the phase distribution. This method was applied to horizontal two-phase flow and a bubble rising in stagnant oil. It was successful in obtaining some pictures of velocity field and phase distribution on the cross section of the pipe. The other is used to visualize a two-dimensional velocity field. This method was applied to a bubble rising in a stagnant water. The velocity field was visualized after and before the passage of a bubble at the measuring cross section. Furthermore, the distribution of liquid velocity was obtained. (author)

  12. Survey of high-velocity molecular gas in the vicinity of Herbig-Haro objects. I

    International Nuclear Information System (INIS)

    Edwards, S.; Snell, R.L.

    1983-01-01

    A survey of high-velocity molecular gas toward 49 Herbig-Haro objects is presented. Observations of the 12 CO J = 1-0 transition obtained with the 14 m telescope of the Five College Radio Astronomy Observatory reveal three new spatially extended high-velocity molecular outflows. One is in the NGC 1333 region near HH 12, and two are in the NGC 7129 region, the first near LkHα 234 and the second near a far-infrared source. The relationship between optical Herbin-Haro emission knots and large-scale motions of the ambient molecular material is investigated, and the properties of high-velocity molecular outflows in the vicinity of Herbig-Haro objects are discussed. Of 11 energetic outflows in the vicinity of Herbig-Haro objects, eight are found in four pairs separated by 0.2-1.0 pc. We estimate that energetic outflows characterized by mass loss rates > or =10 -7 M/sub sun/ yr -1 occur for at least 10 4 yr once in the lifetime of all stars with masses greater than 1M/sub sun/

  13. The boundary condition for vertical velocity and its interdependence with surface gas exchange

    Science.gov (United States)

    Kowalski, Andrew S.

    2017-07-01

    The law of conservation of linear momentum is applied to surface gas exchanges, employing scale analysis to diagnose the vertical velocity (w) in the boundary layer. Net upward momentum in the surface layer is forced by evaporation (E) and defines non-zero vertical motion, with a magnitude defined by the ratio of E to the air density, as w = E/ρ. This is true even right down at the surface where the boundary condition is w|0 = E/ρ|0 (where w|0 and ρ|0 represent the vertical velocity and density of air at the surface). This Stefan flow velocity implies upward transport of a non-diffusive nature that is a general feature of the troposphere but is of particular importance at the surface, where it assists molecular diffusion with upward gas migration (of H2O, for example) but opposes that of downward-diffusing species like CO2 during daytime. The definition of flux-gradient relationships (eddy diffusivities) requires rectification to exclude non-diffusive transport, which does not depend on scalar gradients. At the microscopic scale, the role of non-diffusive transport in the process of evaporation from inside a narrow tube - with vapour transport into an overlying, horizontal airstream - was described long ago in classical mechanics and is routinely accounted for by chemical engineers, but has been neglected by scientists studying stomatal conductance. Correctly accounting for non-diffusive transport through stomata, which can appreciably reduce net CO2 transport and marginally boost that of water vapour, should improve characterisations of ecosystem and plant functioning.

  14. The boundary condition for vertical velocity and its interdependence with surface gas exchange

    Directory of Open Access Journals (Sweden)

    A. S. Kowalski

    2017-07-01

    Full Text Available The law of conservation of linear momentum is applied to surface gas exchanges, employing scale analysis to diagnose the vertical velocity (w in the boundary layer. Net upward momentum in the surface layer is forced by evaporation (E and defines non-zero vertical motion, with a magnitude defined by the ratio of E to the air density, as w = E/ρ. This is true even right down at the surface where the boundary condition is w|0 = E/ρ|0 (where w|0 and ρ|0 represent the vertical velocity and density of air at the surface. This Stefan flow velocity implies upward transport of a non-diffusive nature that is a general feature of the troposphere but is of particular importance at the surface, where it assists molecular diffusion with upward gas migration (of H2O, for example but opposes that of downward-diffusing species like CO2 during daytime. The definition of flux–gradient relationships (eddy diffusivities requires rectification to exclude non-diffusive transport, which does not depend on scalar gradients. At the microscopic scale, the role of non-diffusive transport in the process of evaporation from inside a narrow tube – with vapour transport into an overlying, horizontal airstream – was described long ago in classical mechanics and is routinely accounted for by chemical engineers, but has been neglected by scientists studying stomatal conductance. Correctly accounting for non-diffusive transport through stomata, which can appreciably reduce net CO2 transport and marginally boost that of water vapour, should improve characterisations of ecosystem and plant functioning.

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

    Science.gov (United States)

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

    2016-04-01

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

  16. Comparative study of the discrete velocity and lattice Boltzmann methods for rarefied gas flows through irregular channels

    Science.gov (United States)

    Su, Wei; Lindsay, Scott; Liu, Haihu; Wu, Lei

    2017-08-01

    Rooted from the gas kinetics, the lattice Boltzmann method (LBM) is a powerful tool in modeling hydrodynamics. In the past decade, it has been extended to simulate rarefied gas flows beyond the Navier-Stokes level, either by using the high-order Gauss-Hermite quadrature, or by introducing the relaxation time that is a function of the gas-wall distance. While the former method, with a limited number of discrete velocities (e.g., D2Q36), is accurate up to the early transition flow regime, the latter method (especially the multiple relaxation time (MRT) LBM), with the same discrete velocities as those used in simulating hydrodynamics (i.e., D2Q9), is accurate up to the free-molecular flow regime in the planar Poiseuille flow. This is quite astonishing in the sense that less discrete velocities are more accurate. In this paper, by solving the Bhatnagar-Gross-Krook kinetic equation accurately via the discrete velocity method, we find that the high-order Gauss-Hermite quadrature cannot describe the large variation in the velocity distribution function when the rarefaction effect is strong, but the MRT-LBM can capture the flow velocity well because it is equivalent to solving the Navier-Stokes equations with an effective shear viscosity. Since the MRT-LBM has only been validated in simple channel flows, and for complex geometries it is difficult to find the effective viscosity, it is necessary to assess its performance for the simulation of rarefied gas flows. Our numerical simulations based on the accurate discrete velocity method suggest that the accuracy of the MRT-LBM is reduced significantly in the simulation of rarefied gas flows through the rough surface and porous media. Our simulation results could serve as benchmarking cases for future development of the LBM for modeling and simulation of rarefied gas flows in complex geometries.

  17. Comparative study of the discrete velocity and lattice Boltzmann methods for rarefied gas flows through irregular channels.

    Science.gov (United States)

    Su, Wei; Lindsay, Scott; Liu, Haihu; Wu, Lei

    2017-08-01

    Rooted from the gas kinetics, the lattice Boltzmann method (LBM) is a powerful tool in modeling hydrodynamics. In the past decade, it has been extended to simulate rarefied gas flows beyond the Navier-Stokes level, either by using the high-order Gauss-Hermite quadrature, or by introducing the relaxation time that is a function of the gas-wall distance. While the former method, with a limited number of discrete velocities (e.g., D2Q36), is accurate up to the early transition flow regime, the latter method (especially the multiple relaxation time (MRT) LBM), with the same discrete velocities as those used in simulating hydrodynamics (i.e., D2Q9), is accurate up to the free-molecular flow regime in the planar Poiseuille flow. This is quite astonishing in the sense that less discrete velocities are more accurate. In this paper, by solving the Bhatnagar-Gross-Krook kinetic equation accurately via the discrete velocity method, we find that the high-order Gauss-Hermite quadrature cannot describe the large variation in the velocity distribution function when the rarefaction effect is strong, but the MRT-LBM can capture the flow velocity well because it is equivalent to solving the Navier-Stokes equations with an effective shear viscosity. Since the MRT-LBM has only been validated in simple channel flows, and for complex geometries it is difficult to find the effective viscosity, it is necessary to assess its performance for the simulation of rarefied gas flows. Our numerical simulations based on the accurate discrete velocity method suggest that the accuracy of the MRT-LBM is reduced significantly in the simulation of rarefied gas flows through the rough surface and porous media. Our simulation results could serve as benchmarking cases for future development of the LBM for modeling and simulation of rarefied gas flows in complex geometries.

  18. Prediction of critical transport velocity for preventing sand deposition in gas-oil multiphase production and well systems

    Energy Technology Data Exchange (ETDEWEB)

    Bello, O.O.; Reinicke, K.M. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. of Petroleum Engineering; Teodoriu, C. [Texas A and M Univ., College Station, TX (United States). Dept. of Petroleum Engineering

    2008-10-23

    The critical transport velocity is one of the key parameters for gas-oil-sand multiphase production and well system design and safe operation. Existing American Petroleum Institute Recommended Practice 14E (API RP 14E) for the sizing of multiphase flow systems suggests an equation to calculate threshold transport velocity. This equation only considers mixture density and does not account for factors such as fluid properties, gas-liquid flow patterns, sand loading, sand particle size, size distributions, shape factor and density. This work presents an improved computational methodology, which can be applied to estimate the critical transport velocity required to ensure efficient performance of gas-oil-sand multiphase production and well systems. The improved method is based on the modelling of three-phase gas-oil-sand pipe flow physics from first principle. Computations of the critical transport velocities show reasonable agreement with values calculated from mechanistic model (Danielson, 2007) for a relatively wide range of design and operating conditions. Compared with the mechanistic model (Danielson, 2007), the present method has no imposed limitations to the range of applicability. It is also takes into adequate account the effects of operating pressure, flow geometry, sand particle size, size distribution and shape factor, which have considerable influence on the critical transport velocity in gas-oil-sand multiphase production and well systems. (orig.)

  19. Regional versus detailed velocity analysis to quantify hydrate and free gas in marine sediments : the south Shetland margin case study

    Energy Technology Data Exchange (ETDEWEB)

    Tinivella, U.; Loreto, M.F.; Accaino, F. [Inst. Nazionale di Oceanografia di Geofisica Sperimentale, Trieste (Italy)

    2008-07-01

    The presence of gas hydrate and free gas within marine sediments, deposited along the South Shetland margin, offshore the Antarctic Peninsula, was confirmed by low and high resolution geophysical data, acquired during three research cruises in 1989-1990. Seismic data analysis has demonstrated the presence of a bottom simulating reflector that is very strong and continuous in the eastern part of the margin. This seismic dataset was used in the past to extract detailed velocity information of the shallow structures by using traditional tomographic inversion and jointly tomographic inversion and pre-stack depth migration tool. This paper presented a method to obtain a regional seismic velocity field and information about hydrate and free gas presence in the marine sediments, by using an improved method of the standard analysis of the pre-stack depth migration output. The velocity field was obtained with a layer stripping approach and tomographic inversion of the reflections observed in common image gathering. The paper presented the seismic data and regional and detailed velocity analysis. The results of residual semblance analyses were also presented. Gas phase concentrations were then discussed. The velocity analysis revealed the presence of three main layers characterizing the first kilometer of sediments below the sea floor. In addition, velocity models and related gas-phase sections showed that gas was concentrated in different parts of the profile than where the hydrate was concentrated. This observation confirmed that geological structures and sedimentary processes controlled the gas and hydrate distribution, as observed along other margins. 7 refs., 5 figs.

  20. Carbon isotope evidence for the latitudinal distribution and wind speed dependence of the air-sea gas transfer velocity

    International Nuclear Information System (INIS)

    Krakauer, Nir Y.

    2006-01-01

    The air-sea gas transfer velocity is an important determinant of the exchange of gases, including CO 2 , between the atmosphere and ocean, but the magnitude of the transfer velocity and what factors control it remains poorly known. Here, we use oceanic and atmospheric observations of 14 C and 13 C to constrain the global mean gas transfer velocity as well as the exponent of its wind speed dependence, utilizing the distinct signatures left by the air-sea exchange of 14 CO 2 and 13 CO 2 . While the atmosphere and ocean inventories of 14 CO 2 and 13 CO 2 constrain the mean gas transfer velocity, the latitudinal pattern in the atmospheric and oceanic 14 C and 13 C distributions contain information about the wind speed dependence. We computed the uptake of bomb 14 C by the ocean for different transfer velocity patterns using pulse response functions from an ocean general circulation model, and evaluated the match between the predicted bomb 14 C concentrations and observationally based estimates for the 1970s-1990s. Using a wind speed climatology based on satellite measurements, we solved either for the best-fit global relationship between gas exchange and mean wind speed or for the mean gas transfer velocity over each of 11 ocean regions. We also compared the predicted consequences of different gas exchange relationships on the rate of change and interhemisphere gradient of 14 C in atmospheric CO 2 with tree-ring and atmospheric measurements. Our results suggest that globally, the dependence of the air-sea gas transfer velocity on wind speed is close to linear, with an exponent of 0.5 ± 0.4, and that the global mean gas transfer velocity at a Schmidt number of 660 is 20 ± 3 cm/hr, similar to the results of previous analyses. We find that the air-sea flux of 13 C estimated from atmosphere and ocean observations also suggests a lower than quadratic dependence of gas exchange on wind speed

  1. Measurements of the drift velocity using a small gas chamber for monitoring of the CMS muon system

    CERN Document Server

    Frangenheim, J

    This diploma thesis presents measurements of the drift velocity of electrons in gas. A small gas detector (VDC1 ) is used. This chamber is intended for measurement and monitoring of the drift velocity in the gas of the muon chambers of the gas detector system in the barrel area of the CMS-detector2 at the European Research Center for Particle Physics CERN near Geneva. The drift velocity is, together with the drift time, a key parameter for measurements with drift chambers. The aim of this thesis is to perform test measurements to determine parameters of the chamber and also to estimate systematic errors. Beside the drift velocity, further parameters of the gas like the pressure and the temperature are measured and accounted for. For the further work with the VDCs, analysis software has been created which is used for the analysis of the measurements. Parallel to this work, necessary improvements, e.g. for the high voltage robustness, were also implemented and tested. In addition, studies and test measurements ...

  2. Experimental results showing the internal three-component velocity field and outlet temperature contours for a model gas turbine combustor

    CSIR Research Space (South Africa)

    Meyers, BC

    2011-09-01

    Full Text Available by the American Institute of Aeronautics and Astronautics Inc. All rights reserved ISABE-2011-1129 EXPERIMENTAL RESULTS SHOWING THE INTERNAL THREE-COMPONENT VELOCITY FIELD AND OUTLET TEMPERATURE CONTOURS FOR A MODEL GAS TURBINE COMBUSTOR BC Meyers*, GC... identifier c Position identifier F Fuel i Index L (Combustor) Liner OP Orifice plate Introduction There are often inconsistencies when comparing experimental and Computational Fluid Dynamics (CFD) simulations for gas turbine combustors [1...

  3. A numerical scheme to calculate temperature and salinity dependent air-water transfer velocities for any gas

    Directory of Open Access Journals (Sweden)

    M. T. Johnson

    2010-10-01

    Full Text Available The ocean-atmosphere flux of a gas can be calculated from its measured or estimated concentration gradient across the air-sea interface and the transfer velocity (a term representing the conductivity of the layers either side of the interface with respect to the gas of interest. Traditionally the transfer velocity has been estimated from empirical relationships with wind speed, and then scaled by the Schmidt number of the gas being transferred. Complex, physically based models of transfer velocity (based on more physical forcings than wind speed alone, such as the NOAA COARE algorithm, have more recently been applied to well-studied gases such as carbon dioxide and DMS (although many studies still use the simpler approach for these gases, but there is a lack of validation of such schemes for other, more poorly studied gases. The aim of this paper is to provide a flexible numerical scheme which will allow the estimation of transfer velocity for any gas as a function of wind speed, temperature and salinity, given data on the solubility and liquid molar volume of the particular gas. New and existing parameterizations (including a novel empirical parameterization of the salinity-dependence of Henry's law solubility are brought together into a scheme implemented as a modular, extensible program in the R computing environment which is available in the supplementary online material accompanying this paper; along with input files containing solubility and structural data for ~90 gases of general interest, enabling the calculation of their total transfer velocities and component parameters. Comparison of the scheme presented here with alternative schemes and methods for calculating air-sea flux parameters shows good agreement in general. It is intended that the various components of this numerical scheme should be applied only in the absence of experimental data providing robust values for parameters for a particular gas of interest.

  4. A numerical scheme to calculate temperature and salinity dependent air-water transfer velocities for any gas

    Science.gov (United States)

    Johnson, M. T.

    2010-10-01

    The ocean-atmosphere flux of a gas can be calculated from its measured or estimated concentration gradient across the air-sea interface and the transfer velocity (a term representing the conductivity of the layers either side of the interface with respect to the gas of interest). Traditionally the transfer velocity has been estimated from empirical relationships with wind speed, and then scaled by the Schmidt number of the gas being transferred. Complex, physically based models of transfer velocity (based on more physical forcings than wind speed alone), such as the NOAA COARE algorithm, have more recently been applied to well-studied gases such as carbon dioxide and DMS (although many studies still use the simpler approach for these gases), but there is a lack of validation of such schemes for other, more poorly studied gases. The aim of this paper is to provide a flexible numerical scheme which will allow the estimation of transfer velocity for any gas as a function of wind speed, temperature and salinity, given data on the solubility and liquid molar volume of the particular gas. New and existing parameterizations (including a novel empirical parameterization of the salinity-dependence of Henry's law solubility) are brought together into a scheme implemented as a modular, extensible program in the R computing environment which is available in the supplementary online material accompanying this paper; along with input files containing solubility and structural data for ~90 gases of general interest, enabling the calculation of their total transfer velocities and component parameters. Comparison of the scheme presented here with alternative schemes and methods for calculating air-sea flux parameters shows good agreement in general. It is intended that the various components of this numerical scheme should be applied only in the absence of experimental data providing robust values for parameters for a particular gas of interest.

  5. Effect of Gas Velocity on the Dust Sediment Layer in the Coupled Field of Corona Plasma and Cyclone

    International Nuclear Information System (INIS)

    Wei Mingshan; Ma Chaochen; Li Minghua; Danish, S N

    2006-01-01

    A dust sediment layer was found on the outer tube wall when the ESCP (electrostatic centrifugal precipitator) trapped diesel particulates or ganister sand. The Compton back scatter method was used to measure the sediment thickness during the experiment. The effect of the inlet gas velocity on the dust sediment layer was investigated. PIV (Particle Image Velocimetry) was used to measure the velocity field between the inner barb tube wall and the outer tube wall. Experiments showed that the thickness of the sediment increased with time, and the sediment layer at the lower end was much thicker than that at the upper end. The agglomeration on the outer tube wall could be removed when the inlet gas velocity was increased to a certain value

  6. 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.

  7. A method for measuring the electron drift velocity in working gas using a Frisch-grid ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Huaiyong; Wang, Zhimin; Zhang, Luyu; Chen, Jinxiang; Zhang, Guohui, E-mail: guohuizhang@pku.edu.cn

    2016-12-21

    A method for measuring the electron drift velocity in working gas is proposed. Based on the cathode and the anode signal waveforms of the Frisch-grid ionization chamber, the electron drift velocity is extracted. With this method, the electron drift velocities in Ar + 10% CH{sub 4}, Ar + 3.5% CO{sub 2} and Kr + 2.7% CO{sub 2} gases have been measured and the results are compared with the existing measurements and the simulating results. Using this method, the electron drift velocity can be monitored throughout the experiment of charged particle without bothering the measurement of other parameters, such as the energy and orientation.

  8. A numerical scheme to calculate temperature and salinity dependent air-water transfer velocities for any gas

    Science.gov (United States)

    Johnson, M. T.

    2010-02-01

    The transfer velocity determines the rate of exchange of a gas across the air-water interface for a given deviation from Henry's law equilibrium between the two phases. In the thin film model of gas exchange, which is commonly used for calculating gas exchange rates from measured concentrations of trace gases in the atmosphere and ocean/freshwaters, the overall transfer is controlled by diffusion-mediated films on either side of the air-water interface. Calculating the total transfer velocity (i.e. including the influence from both molecular layers) requires the Henry's law constant and the Schmidt number of the gas in question, the latter being the ratio of the viscosity of the medium and the molecular diffusivity of the gas in the medium. All of these properties are both temperature and (on the water side) salinity dependent and extensive calculation is required to estimate these properties where not otherwise available. The aim of this work is to standardize the application of the thin film approach to flux calculation from measured and modelled data, to improve comparability, and to provide a numerical framework into which future parameter improvements can be integrated. A detailed numerical scheme is presented for the calculation of the gas and liquid phase transfer velocities (ka and kw respectively) and the total transfer velocity, K. The scheme requires only basic physical chemistry data for any gas of interest and calculates K over the full range of temperatures, salinities and wind-speeds observed in and over the ocean. Improved relationships for the wind-speed dependence of ka and for the salinity-dependence of the gas solubility (Henry's law) are derived. Comparison with alternative schemes and methods for calculating air-sea flux parameters shows good agreement in general but significant improvements under certain conditions. The scheme is provided as a downloadable program in the supplementary material, along with input files containing molecular

  9. Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula.

    Science.gov (United States)

    Colina; Arribas; Borne

    1999-12-10

    Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.

  10. Superficial skin ulcers

    International Nuclear Information System (INIS)

    Samaila, Modupeola O.; Rafindadi, Abdulmumini H.; Oluwole, Olabode P.; Adewuyi, Sunday A.

    2007-01-01

    Objective was to determine the underlying cause of superficial skin ulcers over a 15-year period. A retrospective histopathological analysis of 670 cases of superficial skin ulcers diagnosed in the Dept. of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria from January 1991 to December 2005. A total of 670 superficial skin ulcers were analyzed. The mail to female gender ratio was 409:261(1.5:1.0) and a peakage frequency of 44.3 %( 297) in the 5th and 6th decades. Spectrum of lesions encountered was categorized into inflammatory, infections, benign and malignant diseases. The malignant lesions were 309 (46.1%), non-specific inflammation 302 (45.1%), granulation tissue 25 (3.7%) and pseudoepitheliomatous hyperplasia 14 (2.1%). A total of 18(2.7%) specific infections were encountered, which included bacterial, fungal and viral infection. Benign lesions were 2(0.3%), comprising of neurofibroma and Bowen's disease. The most common malignant lesion was squamous cell carcinoma 203 (30.3%) with a male to female ratio of 128:75 (1.7:1.0). Of these 161 were well differentiated tumors. The lower limb was the prevalent site distribution of all the ulcers. Superficial ulcers may be harbinger of malignant diseases. Squamous cell carcinoma remains the most common malignant lesion arising from chronic superficial ulcers from our setting. Adequate tissue biopsy and early diagnosis may reduce the attendant morbidity of these ulcers. (author)

  11. The analog of Blanc's law for drift velocities of electrons in gas mixtures in weakly ionized plasma

    International Nuclear Information System (INIS)

    Chiflikian, R.V.

    1995-01-01

    The analog of Blanc's law for drift velocities of electrons in multicomponent gas mixtures in weakly ionized spatially homogeneous low-temperature plasma is derived. The obtained approximate-analytical expressions are valid for average electron energy in the 1--5 eV range typical for plasma conditions of low-pressure direct current (DC) discharges. The accuracy of these formulas is ±5%. The analytical criterion of the negative differential conductivity (NDC) of electrons in binary mixtures of gases is obtained. NDC of electrons is predicted in He:Kr and He:Xe rare gas mixtures. copyright 1995 American Institute of Physics

  12. Dual-mode nonlinear instability analysis of a confined planar liquid sheet sandwiched between two gas streams of unequal velocities and prediction of droplet size and velocity distribution using maximum entropy formulation

    Science.gov (United States)

    Dasgupta, Debayan; Nath, Sujit; Bhanja, Dipankar

    2018-04-01

    Twin fluid atomizers utilize the kinetic energy of high speed gases to disintegrate a liquid sheet into fine uniform droplets. Quite often, the gas streams are injected at unequal velocities to enhance the aerodynamic interaction between the liquid sheet and surrounding atmosphere. In order to improve the mixing characteristics, practical atomizers confine the gas flows within ducts. Though the liquid sheet coming out of an injector is usually annular in shape, it can be considered to be planar as the mean radius of curvature is much larger than the sheet thickness. There are numerous studies on breakup of the planar liquid sheet, but none of them considered the simultaneous effects of confinement and unequal gas velocities on the spray characteristics. The present study performs a nonlinear temporal analysis of instabilities in the planar liquid sheet, produced by two co-flowing gas streams moving with unequal velocities within two solid walls. The results show that the para-sinuous mode dominates the breakup process at all flow conditions over the para-varicose mode of breakup. The sheet pattern is strongly influenced by gas velocities, particularly for the para-varicose mode. Spray characteristics are influenced by both gas velocity and proximity to the confining wall, but the former has a much more pronounced effect on droplet size. An increase in the difference between gas velocities at two interfaces drastically shifts the droplet size distribution toward finer droplets. Moreover, asymmetry in gas phase velocities affects the droplet velocity distribution more, only at low liquid Weber numbers for the input conditions chosen in the present study.

  13. Effect of Coulomb friction on orientational correlation and velocity distribution functions in a sheared dilute granular gas.

    Science.gov (United States)

    Gayen, Bishakhdatta; Alam, Meheboob

    2011-08-01

    From particle simulations of a sheared frictional granular gas, we show that the Coulomb friction can have dramatic effects on orientational correlation as well as on both the translational and angular velocity distribution functions even in the Boltzmann (dilute) limit. The dependence of orientational correlation on friction coefficient (μ) is found to be nonmonotonic, and the Coulomb friction plays a dual role of enhancing or diminishing the orientational correlation, depending on the value of the tangential restitution coefficient (which characterizes the roughness of particles). From the sticking limit (i.e., with no sliding contact) of rough particles, decreasing the Coulomb friction is found to reduce the density and spatial velocity correlations which, together with diminished orientational correlation for small enough μ, are responsible for the transition from non-gaussian to gaussian distribution functions in the double limit of small friction (μ→0) and nearly elastic particles (e→1). This double limit in fact corresponds to perfectly smooth particles, and hence the maxwellian (gaussian) is indeed a solution of the Boltzmann equation for a frictional granular gas in the limit of elastic collisions and zero Coulomb friction at any roughness. The high-velocity tails of both distribution functions seem to follow stretched exponentials even in the presence of Coulomb friction, and the related velocity exponents deviate strongly from a gaussian with increasing friction.

  14. Amount of gas hydrate estimated from compressional- and shear-wave velocities at the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well

    Science.gov (United States)

    Lee, M.W.

    1999-01-01

    The amount of in situ gas hydrate concentrated in the sediment pore space at the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well was estimated by using compressional-wave (P-wave) and shear-wave (S-wave) downhole log measurements. A weighted equation developed for relating the amount of gas hydrate concentrated in the pore space of unconsolidated sediments to the increase of seismic velocities was applied to the acoustic logs with porosities derived from the formation density log. A weight of 1.56 (W=1.56) and the exponent of 1 (n=1) provided consistent estimates of gas hydrate concentration from the S-wave and the P-wave logs. Gas hydrate concentration is as much as 80% in the pore spaces, and the average gas hydrate concentration within the gas-hydrate-bearing section from 897 m to 1110 m (excluding zones where there is no gas hydrate) was calculated at 39.0% when using P-wave data and 37.8% when using S-wave data.

  15. Effect of flow velocity and temperature on ignition characteristics in laser ignition of natural gas and air mixtures

    Science.gov (United States)

    Griffiths, J.; Riley, M. J. W.; Borman, A.; Dowding, C.; Kirk, A.; Bickerton, R.

    2015-03-01

    Laser induced spark ignition offers the potential for greater reliability and consistency in ignition of lean air/fuel mixtures. This increased reliability is essential for the application of gas turbines as primary or secondary reserve energy sources in smart grid systems, enabling the integration of renewable energy sources whose output is prone to fluctuation over time. This work details a study into the effect of flow velocity and temperature on minimum ignition energies in laser-induced spark ignition in an atmospheric combustion test rig, representative of a sub 15 MW industrial gas turbine (Siemens Industrial Turbomachinery Ltd., Lincoln, UK). Determination of minimum ignition energies required for a range of temperatures and flow velocities is essential for establishing an operating window in which laser-induced spark ignition can operate under realistic, engine-like start conditions. Ignition of a natural gas and air mixture at atmospheric pressure was conducted using a laser ignition system utilizing a Q-switched Nd:YAG laser source operating at 532 nm wavelength and 4 ns pulse length. Analysis of the influence of flow velocity and temperature on ignition characteristics is presented in terms of required photon flux density, a useful parameter to consider during the development laser ignition systems.

  16. Superficies de segundo orden

    OpenAIRE

    Salazar Salazar, Luis Álvaro

    1987-01-01

    Este trabajo se propone poner al alcance de estudiantes de primeros semestres de carreras de aplicación de la matemática, un algoritmo proporcionado por el álgebra lineal, para tratar con mas generalidad, agilidad y libertad unos objetos de la geometría analítica de no fácil manipulación por otros métodos y que se conocen como superficies de segundo orden o superficies cuádricas. En este orden de ideas, el autor considera importante que con este tratamiento se incluya este tema en una asignat...

  17. Transport of temperature-velocity covariance in gas-solid flow and its relation to the axial dispersion coefficient

    Science.gov (United States)

    Subramaniam, Shankar; Sun, Bo

    2015-11-01

    The presence of solid particles in a steady laminar flow generates velocity fluctuations with respect to the mean fluid velocity that are termed pseudo-turbulence. The level of these pseudo-turbulent velocity fluctuations has been characterized in statistically homogeneous fixed particle assemblies and freely evolving suspensions using particle-resolved direct numerical simulation (PR-DNS) by Mehrabadi et al. (JFM, 2015), and it is found to be a significant contribution to the total kinetic energy associated with the flow. The correlation of these velocity fluctuations with temperature (or a passive scalar) generates a flux term that appears in the transport equation for the average fluid temperature (or average scalar concentration). The magnitude of this transport of temperature-velocity covariance is quantified using PR-DNS of thermally fully developed flow past a statistically homogeneous fixed assembly of particles, and the budget of the average fluid temperature equation is presented. The relation of this transport term to the axial dispersion coefficient (Brenner, Phil. Trans. Roy. Soc. A, 1980) is established. The simulation results are then interpreted in the context of our understanding of axial dispersion in gas-solid flow. NSF CBET 1336941.

  18. Air–Sea CO2 Gas Transfer Velocity in a Shallow Estuary

    DEFF Research Database (Denmark)

    Mørk, Eva Thorborg; Sørensen, Lise Lotte; Jensen, Bjarne

    2014-01-01

    The air–sea transfer velocity of CO2(kCO2) was investigated in a shallow estuary in March to July 2012, using eddy-covariance measurements of CO2 fluxes and measured air–sea CO2 partial-pressure differences. A data evaluation method that eliminates data by nine rejection criteria in order......, the transfer velocity in the shallow water estuary was lower than in other coastal waters, possibly a symptom of low tidal amplitude leading to low intensity water turbulence. High transfer velocities were recorded above wind speeds of 5 m s−1 , believed to be caused by early-breaking waves and the large fetch...... (6.5 km) of the estuary. These findings indicate that turbulence in both air and water influences the transfer velocity....

  19. Use of a Tantalum Liner to Reduce Bore Erosion and Increase Muzzle Velocity in Two-Stage Light Gas Guns

    Science.gov (United States)

    Bogdanoff, David W.

    2015-01-01

    Muzzle velocities and gun erosion predicted by earlier numerical simulations of two stage light gas guns with steel gun tubes were in good agreement with experimental values. In a subsequent study, simulations of high performance shots were repeated with rhenium (Re) gun tubes. Large increases in muzzle velocity (2 - 4 km/sec) were predicted for Re tubes. In addition, the hydrogen-produced gun tube erosion was, in general, predicted to be zero with Re tubes. Tantalum (Ta) has some mechanical properties superior to those of Re. Tantalum has a lower modulus of elasticity than Re for better force transmission from the refractory metal liner to an underlying thick wall steel tube. Tantalum also has greater ductility than Re for better survivability during severe stress/strain cycles. Also, tantalum has been used as a coating or liner in military powder guns with encouraging results. Tantalum has, however, somewhat inferior thermal properties to those of rhenium, with a lower melting point and lower density and thermal conductivity. The present study was undertaken to see to what degree the muzzle velocity gains of rhenium gun tubes (over steel tubes) could be achieved with tantalum gun tubes. Nine high performance shots were modeled with a new version of our CFD gun code for steel, rhenium and tantalum gun tubes. For all except the highest velocity shot, the results with Ta tubes were nearly identical with those for Re tubes. Even for the highest velocity shot, the muzzle velocity gain over a steel tube using Ta was 82% of the gain obtained using Re. Thus, the somewhat inferior thermal properties of Ta (when compared to those of Re) translate into only very slightly poorer overall muzzle velocity performance. When this fact is combined with the superior mechanical properties of Ta and the encouraging performance of Ta liners/coatings in military powder guns, tantalum is to be preferred over Re as a liner/coating material for two stage light gas guns to increase muzzle

  20. Rotina computacional para a determinação da velocidade de sedimentação das partículas do solo em suspensão no escoamento superficial Computational routine for the determination of the sedimentation velocity of the soil particles in the drain

    Directory of Open Access Journals (Sweden)

    Luiz F. C. de Oliveira

    2005-04-01

    Full Text Available O presente trabalho teve como objetivo desenvolver uma rotina computacional para a determinação da velocidade de deposição de partículas em suspensão no escoamento superficial, verificar sua aplicação por intermédio de modelo de transporte de sedimentos e comparar os resultados obtidos com dados experimentais. Empregou-se na rotina o processo iterativo de Newton-Rapshon para a solução das equações empregadas na determinação da velocidade de deposição de partículas em suspensão no escoamento superficial, e na solução da equação do transporte de sedimentos empregou-se a técnica das diferenças finitas. Essas rotinas foram empregadas na implementação do modelo MTSES (Modelo para Transporte de Solutos no Solo e no Escoamento Superficial. As velocidades de queda das partículas obtidas pela rotina desenvolvida, em média, foram superestimadas, com erro relativo médio de 0,63%, o que possibilitou a utilização da rotina desenvolvida no MTSES. O modelo MTSES superestimou o total de sedimentos transportados pelo escoamento superficial para todas as intensidades de precipitação empregadas neste estudo, com variações porcentuais de 15,6 a 58,3%.The present work had as objective to develop a computational routine for the determination of the sedimentation velocity in the drain and to verify its application through a model of transport of sediments and to compare the results obtained with experimental data. It was used in the routine the iterative process of Newton-Rapshon for the solution of the equations applied in the determination of the sedimentation velocity in the drain, and on the solution of the transport of sediments equation was applied the technique of the finite differences. Those routines were used in the implementation of the model MTSES (Model for solute transport in the soil and in the drain. The sedimentation velocities obtained by the developed routine were overestimated, with a medium relative error of 0

  1. Effect of wind waves on air-sea gas exchange: proposal of an overall CO2 transfer velocity formula as a function of breaking-wave parameter

    International Nuclear Information System (INIS)

    Zhao, D.; Suzuki, Y.; Komori, S.

    2003-01-01

    A new formula for gas transfer velocity as a function of the breaking-wave parameter is proposed based on correlating gas transfer with whitecap coverage. The new formula for gas transfer across an air-sea interface depends not only on wind speed but also on wind-wave state. At the same wind speed, a higher gas transfer velocity will be obtained for a more developed wind-sea, which is represented by a smaller spectral peak frequency of wind waves. We suggest that the large uncertainties in the traditional relationship of gas transfer velocity with wind speed be ascribed to the neglect of the effect of wind waves. The breaking-wave parameter can be regarded as a Reynolds number that characterizes the intensity of turbulence associated with wind waves in the downward-bursting boundary layer (DBBL). DBBL provides an effective way to exchange gas across the air-sea interface, which might be related to the surface renewal

  2. Nonintrusive transceiver and method for characterizing temperature and velocity fields in a gas turbine combustor

    Science.gov (United States)

    DeSilva, Upul P.; Claussen, Heiko

    2017-09-05

    An acoustic transceiver is implemented for measuring acoustic properties of a gas in a turbine engine combustor. The transceiver housing defines a measurement chamber and has an opening adapted for attachment to a turbine engine combustor wall. The opening permits propagation of acoustic signals between the gas in the turbine engine combustor and gas in the measurement chamber. An acoustic sensor mounted to the housing receives acoustic signals propagating in the measurement chamber, and an acoustic transmitter mounted to the housing creates acoustic signals within the measurement chamber. An acoustic measurement system includes at least two such transceivers attached to a turbine engine combustor wall and connected to a controller.

  3. Effective ionization coefficients, electron drift velocities, and limiting breakdown fields for gas mixtures of possible interest to particle detectors

    International Nuclear Information System (INIS)

    Datskos, P.G.

    1991-01-01

    We have measured the gas-density, N, normalized effective ionization coefficient, bar a/N, and the electron drift velocity, w, as a function of the density-reduced electric field, E/N, and obtained the limiting, (E/N) lim , value of E/N for the unitary gases Ar, CO 2 , and CF 4 , the binary gas mixtures CO 2 :Ar (20: 80), CO 2 :CH 4 (20:80), and CF 4 :Ar (20:80), and the ternary gas mixtures CO 2 :CF 4 :Ar (10:10:80) and H 2 O: CF 4 :Ar (2:18:80). Addition of the strongly electron thermalizing gas CO 2 or H 2 O to the binary mixture CF 4 :Ar (1)''cools'' the mixture (i.e., lowers the electron energies), (2) has only a small effect on the magnitude of w(E/N) in the E/N range employed in the particle detectors, and (3) increases bar a/N for E/N ≥ 50 x 10 -17 V cm 2 . The increase in bar a/N, even though the electron energies are lower in the ternary mixture, is due to the Penning ionization of CO 2 (or H 2 O) in collisions with excited Ar* atoms. The ternary mixtures -- being fast, cool, and efficient -- have potential for advanced gas-filled particle detectors such as those for the SCC muon chambers. 17 refs., 8 figs., 1 tab

  4. Gas-hydrate concentration estimated from P- and S-wave velocities at the Mallik 2L-38 research well, Mackenzie Delta, Canada

    Science.gov (United States)

    Carcione, José M.; Gei, Davide

    2004-05-01

    We estimate the concentration of gas hydrate at the Mallik 2L-38 research site using P- and S-wave velocities obtained from well logging and vertical seismic profiles (VSP). The theoretical velocities are obtained from a generalization of Gassmann's modulus to three phases (rock frame, gas hydrate and fluid). The dry-rock moduli are estimated from the log profiles, in sections where the rock is assumed to be fully saturated with water. We obtain hydrate concentrations up to 75%, average values of 37% and 21% from the VSP P- and S-wave velocities, respectively, and 60% and 57% from the sonic-log P- and S-wave velocities, respectively. The above averages are similar to estimations obtained from hydrate dissociation modeling and Archie methods. The estimations based on the P-wave velocities are more reliable than those based on the S-wave velocities.

  5. Common Superficial Bursitis.

    Science.gov (United States)

    Khodaee, Morteza

    2017-02-15

    Superficial bursitis most often occurs in the olecranon and prepatellar bursae. Less common locations are the superficial infrapatellar and subcutaneous (superficial) calcaneal bursae. Chronic microtrauma (e.g., kneeling on the prepatellar bursa) is the most common cause of superficial bursitis. Other causes include acute trauma/hemorrhage, inflammatory disorders such as gout or rheumatoid arthritis, and infection (septic bursitis). Diagnosis is usually based on clinical presentation, with a particular focus on signs of septic bursitis. Ultrasonography can help distinguish bursitis from cellulitis. Blood testing (white blood cell count, inflammatory markers) and magnetic resonance imaging can help distinguish infectious from noninfectious causes. If infection is suspected, bursal aspiration should be performed and fluid examined using Gram stain, crystal analysis, glucose measurement, blood cell count, and culture. Management depends on the type of bursitis. Acute traumatic/hemorrhagic bursitis is treated conservatively with ice, elevation, rest, and analgesics; aspiration may shorten the duration of symptoms. Chronic microtraumatic bursitis should be treated conservatively, and the underlying cause addressed. Bursal aspiration of microtraumatic bursitis is generally not recommended because of the risk of iatrogenic septic bursitis. Although intrabursal corticosteroid injections are sometimes used to treat microtraumatic bursitis, high-quality evidence demonstrating any benefit is unavailable. Chronic inflammatory bursitis (e.g., gout, rheumatoid arthritis) is treated by addressing the underlying condition, and intrabursal corticosteroid injections are often used. For septic bursitis, antibiotics effective against Staphylococcus aureus are generally the initial treatment, with surgery reserved for bursitis not responsive to antibiotics or for recurrent cases. Outpatient antibiotics may be considered in those who are not acutely ill; patients who are acutely ill

  6. SUPERFICIAL CERVICAL PLEXUS BLOCK

    Directory of Open Access Journals (Sweden)

    Komang Mega Puspadisari

    2014-01-01

    Full Text Available Superficial cervical plexus block is one of the regional anesthesia in  neck were limited to thesuperficial fascia. Anesthesia is used to relieve pain caused either during or after the surgery iscompleted. This technique can be done by landmark or with ultrasound guiding. The midpointof posterior border of the Sternocleidomastoid was identified and the prosedure done on thatplace or on the level of cartilage cricoid.

  7. An analysis of numerical convergence in discrete velocity gas dynamics for internal flows

    Science.gov (United States)

    Sekaran, Aarthi; Varghese, Philip; Goldstein, David

    2018-07-01

    The Discrete Velocity Method (DVM) for solving the Boltzmann equation has significant advantages in the modeling of non-equilibrium and near equilibrium flows as compared to other methods in terms of reduced statistical noise, faster solutions and the ability to handle transient flows. Yet the DVM performance for rarefied flow in complex, small-scale geometries, in microelectromechanical (MEMS) devices for instance, is yet to be studied in detail. The present study focuses on the performance of the DVM for locally large Knudsen number flows of argon around sharp corners and other sources for discontinuities in the distribution function. Our analysis details the nature of the solution for some benchmark cases and introduces the concept of solution convergence for the transport terms in the discrete velocity Boltzmann equation. The limiting effects of the velocity space discretization are also investigated and the constraints on obtaining a robust, consistent solution are derived. We propose techniques to maintain solution convergence and demonstrate the implementation of a specific strategy and its effect on the fidelity of the solution for some benchmark cases.

  8. Visualization and measurement of liquid velocity field of gas-liquid metal two-phase flow using neutron radiography

    International Nuclear Information System (INIS)

    Saito, Yasushi; Suzuki, Tohru; Matsubayashi, Masahito

    2000-01-01

    In a core melt accident of a fast breeder reactor, a possibility of re-criticality is anticipated in the molten fuel-steel mixture pool. One of the mechanisms to suppress the re-criticality is the boiling of steel in the molten fuel-steel mixture pool because of the negative void reactivity effect. To evaluate the reactivity change due to boiling, it is necessary to know the characteristics of gas-liquid two-phase flow in the molten fuel-steel mixture pool. For this purpose, boiling bubbles in a molten fuel-steel mixture pool were simulated by adiabatic gas bubbles in a liquid metal pool to study the basic characteristics of gas-liquid metal two-phase mixture. Visualization of the two-phase mixture and measurements of liquid phase velocity and void fraction were conducted by using neutron radiography and image processing techniques. From these measurements, the basic characteristics of gas-liquid metal two-phase mixture were clarified. (author)

  9. Characterization of a porcine model of chronic superficial varicose veins.

    Science.gov (United States)

    Jones, Gregory T; Grant, Mark W; Thomson, Ian A; Hill, B Geraldine; van Rij, André M

    2009-06-01

    Previous animal models of venous disease, while inducing venous hypertension and valvular insufficiency, do not produce superficial varicose veins. In this study, we aimed to develop and characterize a pig-based model of superficial varicose veins. Right femoral arteriovenous fistulae (AVF) were surgically fashioned in young adult pigs. Animals were examined at postoperative times up to 15 weeks to determine the development of varicose veins and measurement of both blood pressure and flow velocities within the superficial thigh veins. Histology and vascular corrosion casts were used to characterize the resulting structural venous alterations. Porcine pathophysiological features were compared with those of human primary superficial varicose veins. Gross superficial varicosities developed over the ipsilateral medial thigh region after an initial lag period of 1-2 weeks. Veins demonstrated retrograde filling with valvular incompetence, and a moderate, non-pulsatile, venous hypertension, which was altered by changes in posture and Valsalva. Venous blood flow velocities were elevated to 15-30 cm/s in varicose veins. Structurally, pig varicose veins were enlarged, tortuous, had valvular degeneration, and regions of focal medial atrophy with or without overlying intimal thickening. The superficial varicose veins, which developed within this model, have a pathophysiology that is consistent with that observed in humans. The porcine femoral AVF model is proposed as a suitable experimental model to evaluate the pathobiology of superficial venous disease. It may also be suitable for the evaluation of treatment interventions including drug therapy.

  10. Numerical study to invistigate the effect of inlet gas velocity and Reynolds number on bubble formation in a viscous liquid

    Directory of Open Access Journals (Sweden)

    Islam Tariqul

    2015-01-01

    Full Text Available Bubble formation dynamics has great value in mineral recovery and the oil industry. In this paper, a single bubble formation process through an orifice in a rectangle domain is modelled to study the bubble formation characteristics using the volume of fluid (VOF with the continuum surface force (CSF method. The effect of gas inlet velocities, Ug ~ 0.1 - 0.3 m/s on bubble formation stages (i.e., expansion, elongation and pinch off, bubble contact angle, dynamics and static pressure, bubble departure diameter etc. was investigated through an orifice diameter of 1 mm. The method was also used to study the effect of Reynolds number, Reμ ~ 1.32 - 120 on bubble formation when all other parameters were kept constant. It is found that a high inlet gas velocity accelerated the reducing of the bubble contact angle from an obtuse angle to an acute angle and the faster development of hemispherical shape of the bubble. It is also found that an increasing of Reynolds number caused speeding up of the bubble pinch-off and formed a smaller bubble neck height due to stronger vortex ring around the bubble neck.

  11. Characteristics of low-mass-velocity vertical gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Adachi, Hiromichi; Abe, Yutaka; Kimura, Ko-ji

    1995-01-01

    In the present paper, characteristics of low mass velocity two-phase flow was analyzed based on a concept that pressure energy of two-phase flow is converted into acceleration work, gravitational work and frictional work, and the pressure energy consumption rate should be minimum at the stable two-phase flow condition. Experimental data for vertical upward air-water two-phase flow at atmospheric pressure was used to verify this concept and the turbulent model used in this method is optimized with the data. (author)

  12. Transport processes and sound velocity in vibrationally non-equilibrium gas of anharmonic oscillators

    Science.gov (United States)

    Rydalevskaya, Maria A.; Voroshilova, Yulia N.

    2018-05-01

    Vibrationally non-equilibrium flows of chemically homogeneous diatomic gases are considered under the conditions that the distribution of the molecules over vibrational levels differs significantly from the Boltzmann distribution. In such flows, molecular collisions can be divided into two groups: the first group corresponds to "rapid" microscopic processes whereas the second one corresponds to "slow" microscopic processes (their rate is comparable to or larger than that of gasdynamic parameters variation). The collisions of the first group form quasi-stationary vibrationally non-equilibrium distribution functions. The model kinetic equations are used to study the transport processes under these conditions. In these equations, the BGK-type approximation is used to model only the collision operators of the first group. It allows us to simplify derivation of the transport fluxes and calculation of the kinetic coefficients. Special attention is given to the connection between the formulae for the bulk viscosity coefficient and the sound velocity square.

  13. Multiple mechanisms generate a universal scaling with dissipation for the air-water gas transfer velocity

    Science.gov (United States)

    Katul, Gabriel; Liu, Heping

    2017-02-01

    A large corpus of field and laboratory experiments support the finding that the water side transfer velocity kL of sparingly soluble gases near air-water interfaces scales as kL˜(νɛ)1/4, where ν is the kinematic water viscosity and ɛ is the mean turbulent kinetic energy dissipation rate. Originally predicted from surface renewal theory, this scaling appears to hold for marine and coastal systems and across many environmental conditions. It is shown that multiple approaches to representing the effects of turbulence on kL lead to this expression when the Kolmogorov microscale is assumed to be the most efficient transporting eddy near the interface. The approaches considered range from simplified surface renewal schemes with distinct models for renewal durations, scaling and dimensional considerations, and a new structure function approach derived using analogies between scalar and momentum transfer. The work offers a new perspective as to why the aforementioned 1/4 scaling is robust.

  14. DEPENDENCE OF THE TURBULENT VELOCITY FIELD ON GAS DENSITY IN L1551

    International Nuclear Information System (INIS)

    Yoshida, Atsushi; Kitamura, Yoshimi; Shimajiri, Yoshito; Kawabe, Ryohei

    2010-01-01

    We have carried out mapping observations of the entire L1551 molecular cloud with about 2 pc x 2 pc size in the 12 CO(1-0) line with the Nobeyama 45 m radio telescope at the high effective resolution of 22'' (corresponding to 0.017 pc at the distance of 160 pc), and analyzed the 12 CO data together with the 13 CO(1-0) and C 18 O(1-0) data from the Nobeyama Radio Observatory database. We derived the new non-thermal line width-size relations, σ NT ∝ L γ , for the three molecular lines, corrected for the effect of optical depth and the line-of-sight integration. To investigate the characteristic of the intrinsic turbulence, the effects of the outflows were removed. The derived relations are (σ NT /km s -1 ) = (0.18 ± 0.010)(L/pc) 0.45±0.095 , (0.20 ± 0.020)(L/pc) 0.48±0.091 , and (0.22 ± 0.050) (L/pc) 0.54±0.21 for the 12 CO, 13 CO, and C 18 O lines, respectively, suggesting that the line width-size relation of the turbulence very weakly depends on our observed molecular lines, i.e., the relation does not change between the density ranges of 10 2 -10 3 and 10 3 -10 4 cm -3 . In addition, the relations indicate that incompressible turbulence is dominant at the scales smaller than 0.6 pc in L1551. The power spectrum indices converted from the relations, however, seem to be larger than that of the Kolmogorov spectrum for incompressible flow. The disagreement could be explained by the anisotropy in the turbulent velocity field in L1551, as expected in MHD turbulence. Actually, the autocorrelation functions of the centroid velocity fluctuations show larger correlation along the direction of the magnetic field measured for the whole Taurus cloud, which is consistent with the results of numerical simulations for incompressible MHD flow.

  15. Superficial fungal infections.

    Science.gov (United States)

    Schwartz, Robert A

    Superficial fungal infections arise from a pathogen that is restricted to the stratum corneum, with little or no tissue reaction. In this Seminar, three types of infection will be covered: tinea versicolor, piedra, and tinea nigra. Tinea versicolor is common worldwide and is caused by Malassezia spp, which are human saprophytes that sometimes switch from yeast to pathogenic mycelial form. Malassezia furfur, Malassezia globosa, and Malassezia sympodialis are most closely linked to tinea versicolor. White and black piedra are both common in tropical regions of the world; white piedra is also endemic in temperate climates. Black piedra is caused by Piedraia hortae; white piedra is due to pathogenic species of the Trichosporon genus. Tinea nigra is also common in tropical areas and has been confused with melanoma.

  16. PRESENT-DAY GALACTIC EVOLUTION: LOW-METALLICITY, WARM, IONIZED GAS INFLOW ASSOCIATED WITH HIGH-VELOCITY CLOUD COMPLEX A

    Energy Technology Data Exchange (ETDEWEB)

    Barger, K. A.; Haffner, L. M.; Wakker, B. P.; Hill, Alex S. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Madsen, G. J. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Duncan, A. K., E-mail: kbarger@astro.wisc.edu, E-mail: haffner@astro.wisc.edu, E-mail: Alex.Hill@csiro.au, E-mail: wakker@astro.wisc.edu, E-mail: greg.madsen@sydney.edu.au [Rose-Hulman Institute of Technology, Terre Haute, IN 47803 (United States)

    2012-12-20

    The high-velocity cloud Complex A is a probe of the physical conditions in the Galactic halo. The kinematics, morphology, distance, and metallicity of Complex A indicate that it represents new material that is accreting onto the Galaxy. We present Wisconsin H{alpha} Mapper kinematically resolved observations of Complex A over the velocity range of -250 to -50 km s{sup -1} in the local standard of rest reference frame. These observations include the first full H{alpha} intensity map of Complex A across (l, b) = (124 Degree-Sign , 18 Degree-Sign ) to (171 Degree-Sign , 53 Degree-Sign ) and deep targeted observations in H{alpha}, [S II] {lambda}6716, [N II] {lambda}6584, and [O I] {lambda}6300 toward regions with high H I column densities, background quasars, and stars. The H{alpha} data imply that the masses of neutral and ionized material in the cloud are similar, both being greater than 10{sup 6} M{sub Sun }. We find that the Bland-Hawthorn and Maloney model for the intensity of the ionizing radiation near the Milky Way is consistent with the known distance of the high-latitude part of Complex A and an assumed cloud geometry that puts the lower-latitude parts of the cloud at a distance of 7-8 kpc. This compatibility implies a 5% ionizing photon escape fraction from the Galactic disk. We also provide the nitrogen and sulfur upper abundance solutions for a series of temperatures, metallicities, and cloud configurations for purely photoionized gas; these solutions are consistent with the sub-solar abundances found by previous studies, especially for temperatures above 10{sup 4} K or for gas with a high fraction of singly ionized nitrogen and sulfur.

  17. Video imaging measurement of interfacial wave velocity in air-water flow through a horizontal elbow

    Science.gov (United States)

    Al-Wazzan, Amir; Than, Cheok F.; Moghavvemi, Mahmoud; Yew, Chia W.

    2001-10-01

    Two-phase flow in pipelines containing elbows represents a common situation in the oil and gas industries. This study deals with the stratified flow regime between the gas and liquid phase through an elbow. It is of interest to study the change in wave characteristics by measuring the wave velocity and wavelength at the inlet and outlet of the elbow. The experiments were performed under concurrent air-water stratified flow in a horizontal transparent polycarbonate pipe of 0.05m diameter and superficial air and water velocities up to 8.97 and 0.0778 m/s respectively. A non-intrusive video imaging technique was applied to capture the waves. For image analysis, a frame by frame direct overlapping method was used to detect for pulsating flow and a pixel shifting method based on the detection of minimum values in the overlap function was used to determine wave velocity and wavelength. Under superficial gas velocity of less than 4.44 m/s, the results suggest a regular pulsating outflow produced by the elbow. At higher gas velocities, more random pulsation was found and the emergence of localized interfacial waves was detected. Wave velocities measured by this technique were found to produce satisfactory agreement with direct measurements.

  18. 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.

  19. Void fraction and interfacial velocity in gas-liquid upward two-phase flow across tube bundles

    International Nuclear Information System (INIS)

    Ueno, T.; Tomomatsu, K.; Takamatsu, H.; Nishikawa, H.

    1997-01-01

    Tube failures due to flow-induced vibration are a major problem in heat exchangers and many studies on the problem of such vibration have been carried out so far. Most studies however, have not focused on two-phase flow behavior in tube bundles, but have concentrated mainly on tube vibration behavior like fluid damping, fluid elastic instability and so on. Such studies are not satisfactory for understanding the design of heat exchangers. Tube vibration behavior is very complicated, especially in the case of gas-liquid two-phase flow, so it is necessary to investigate two-phase flow behavior as well as vibration behavior before designing heat exchangers. This paper outlines the main parameters that characterize two-phase behavior, such as void fraction and interfacial velocity. The two-phase flow analyzed here is gas-liquid upward flow across a horizontal tube bundle. The fluids tested were HCFC-123 and steam-water. HCFC-123 stands for Hydrochlorofluorocarbon. Its chemical formula is CHCl 2 CF 3 , which has liquid and gas densities of 1335 and 23.9 kg/m 3 at a pressure of 0.40 MPa and 1252 and 45.7 kg/m 3 at a pressure of 0.76 MPa. The same model tube bundle was used in the two tests covered in this paper, to examine the similarity law of two-phase flow behavior in tube bundles using HCFC-123 and steam-water two-phase flow. We also show numerical simulation results for the two fluid models in this paper. We do not deal with vibration behavior and the relationship between vibration behavior and two-phase flow behavior. (author)

  20. One-step synthesis of dimethyl ether from the gas mixture containing CO2 with high space velocity

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Lin, Bo-Jhih; Lee, How-Ming; Huang, Men-Han

    2012-01-01

    Highlights: ► A bifunctional catalyst for DME synthesis is prepared using a coprecipitation method. ► The DME synthesis from syngas at a high space velocity of is investigated. ► The reaction is dominated by chemical kinetics at lower reaction temperatures. ► Thermodynamic equilibrium governs the reaction at higher temperatures. ► 0.2 g of ZSM5 is sufficient to be blended with 1 g of the catalyst for DME synthesis. -- Abstract: Dimethyl ether (DME) has been considered as a potential hydrogen carrier used in fuel cells; it can also be consumed as a diesel substitute or chemicals. To develop the technique of DME synthesis, a bifunctional Cu–ZnO–Al 2 O 3 /ZSM5 catalyst is prepared using a coprecipitation method. The reaction characteristics of DME synthesis from syngas at a high space velocity of 15,000 mL (g cat h) −1 are investigated and the effects of reaction temperature, pressure, CO 2 concentration and ZSM5 amount on the synthesis are taken into account. The results suggest that an increase in CO 2 concentration in the feed gas substantially decreases the DME formation. The optimum reaction temperature always occurs at 225 °C, regardless of what the pressure is. It is thus recognized that the DME synthesis is governed by two different mechanisms when the reaction temperature varies. At lower reaction temperatures ( 225 °C). For the CO 2 content of 5 vol.% and the pressure of 40 atm, the maximum DME yield is 1.89 g (g cat h) −1 . It is also found that 0.2 g of ZSM5 is sufficient to be blended with 1 g of the catalyst for DME synthesis.

  1. Observations of high-velocity molecular gas near Herbig-Haro objects: HH 24--27 and HH 1--2

    International Nuclear Information System (INIS)

    Snell, R.L.; Edwards, S.

    1982-01-01

    High-velocity CO has been detected in the vicinity of the Herbig-Haro objects HH 24--27. These observations indicate that there are two sources of high-velocity outflow; one centered on an infrared source near HH 26, and the second centered roughly 2' south of HH 24. The redshifted and blueshifted wings in both sources are spatially separated suggesting that the high-velocity gas is due to energetic bipolar outflow from young stars embedded in the molecular cloud. The association of Herbig-Haro objects with regions of high-velocity gas suggests a common origin for both in the interaction of a stellar wind with the ambient molecular cloud. The mass loss rates implied by our observations, assuming that the rate of mass loss has been constant throughout the dynamical lifetime of the bipolar lobes, are roughly 10 -6 M/sub sun/ yr -1 for both sources. We have also searched for high-velocity gas near HH 1--2 but found no evidence for mass outflow in this region

  2. Understanding the formation process of the liquid slug in a hilly-terrain wet natural gas pipeline

    DEFF Research Database (Denmark)

    Yang, Yan; Li, Jingbo; Wang, Shuli

    2017-01-01

    condition on the liquid slug formation is discussed including pipe diameter, inclination angle, gas superficial velocity and liquid holdup. The results show that the pipe is blocked by the liquid slug at the moment of slug formed. The pipe pressure suddenly increases, and then decreases gradually...... in the process of liquid slug formation and motion. The pipe pressure drop and liquid holdup decrease along with the increasing inclination angle of ascending pipe. On the contrary, they rise with the increase of the inclination angle of descending pipe. Higher gas superficial velocity and liquid holdup result...

  3. The analysis of coolant-velocity distribution in plat-typed fuel element using CFD method for RSG-GAS research reactor

    International Nuclear Information System (INIS)

    Muhammad Subekti; Darwis Isnaini; Endiah Puji Hastuti

    2013-01-01

    The measurement experiment for coolant-velocity distribution in the subchannel of fuel element of RSG-GAS research reactor is difficult to be carried out due to too narrow channel and subchannel placed inside the fuel element. Hence, the calculation is required to predict the coolant-velocity distribution inside subchannel to confirm that the handle presence does not ruin the velocity distribution into every subchannel. This calculation utilizes CFD method, which respect to 3-dimension interior. Moreover, the calculation of coolant-velocity distribution inside subchannel was not ever carried out. The research object is to investigate the distribution of coolant-velocity in plat-typed fuel element using 3-dimension CFD method for RSG-GAS research reactor. This research is required as a part of the development of thermalhydraulic design of fuel element for innovative research reactor as well. The modeling uses ½ model in Gambit software and calculation uses turbulence equation in FLUENT 6.3 software. Calculation result of 3D coolant-velocity in subchannel using CFD method is lower about 4.06 % than 1D calculation result due to 1D calculation obeys handle availability. (author)

  4. Mean ascending velocity of powder entrained by gas in a packed bed; Juten sonai ni okeru kiryu ni dohansareru funtai no heikin josho sokudo

    Energy Technology Data Exchange (ETDEWEB)

    Ariyama, T; Sato, M; Asakawa, Y [NKK Corp., Tokyo (Japan)

    1996-01-20

    For the purpose of clarifying the behavior of fine particles entrained by upward gas in the packed bed like in a blast furnace, the mean ascending velocity of powder in the packed bed was measured by the residence time distribution of the tracer powder. According the results, it was found that the measured velocity was lower than the values predicted by the successive collision model of fine particles. The difference is considered to be caused by the stagnant zone of fine particles on the packed materials, and this behavior was confirmed by the observation in the two dimensional experimental apparatus. Namely, the dynamic hold-up of powder in the packed bed was composed of the particles entrained by the upward gas and the stagnant particles on the packed material, and the latter part was successively renewed by the powder carried by gas. Then, on the basis of the above results, the relation between stagnant time and local ascending velocity were experimentally correlated with solid-gas loading ratio, and it was found that there exists a certain relation among them. The model proposed by these experiments enabled to calculate the mean ascending velocity of powder in the packed bed. 6 refs., 11 figs., 1 tab.

  5. Long-time tails of the velocity autocorrelation function in 2D and 3D lattice gas cellular automata: a test of mode-coupling theory

    NARCIS (Netherlands)

    Hoef, M.A. van der; Frenkel, D.

    1990-01-01

    We report simulations of the velocity autocorrelation function (VACF) of a tagged particle in two- and three-dimensional lattice-gas cellular automata, using a new technique that is about a million times more efficient than the conventional techniques. The simulations clearly show the algebraic

  6. What factors control superficial lava dome explosivity?

    Science.gov (United States)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J

    2015-09-30

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management.

  7. What factors control the superficial lava dome explosivity?

    Science.gov (United States)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoit; Morgan, Daniel J.

    2015-04-01

    Dome-forming eruption is a frequent eruptive style; lava domes result from intermittent, slow extrusion of viscous lava. Most dome-forming eruptions produce highly microcrystallized and highly- to almost totally-degassed magmas which have a low explosive potential. During lava dome growth, recurrent collapses of unstable parts are the main destructive process of the lava dome, generating concentrated pyroclastic density currents (C-PDC) channelized in valleys. These C-PDC have a high, but localized, damage potential that largely depends on the collapsed volume. Sometimes, a dilute ash cloud surge develops at the top of the concentrated flow with an increased destructive effect because it may overflow ridges and affect larger areas. In some cases, large lava dome collapses can induce a depressurization of the magma within the conduit, leading to vulcanian explosions. By contrast, violent, laterally directed, explosions may occur at the base of a growing lava dome: this activity generates dilute and turbulent, highly-destructive, pyroclastic density currents (D-PDC), with a high velocity and propagation poorly dependent on the topography. Numerous studies on lava dome behaviors exist, but the triggering of lava dome explosions is poorly understood. Here, seven dome-forming eruptions are investigated: in the Lesser Antilles arc: Montagne Pelée, Martinique (1902-1905, 1929-1932 and 650 y. BP eruptions), Soufrière Hills, Montserrat; in Guatemala, Santiaguito (1929 eruption); in La Chaîne des Puys, France (Puy de Dome and Puy Chopine eruptions). We propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by these key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite

  8. PREDICTION OF GAS HOLD-UP IN A COMBINED LOOP AIR LIFT FLUIDIZED BED REACTOR USING NEWTONIAN AND NON-NEWTONIAN LIQUIDS

    Directory of Open Access Journals (Sweden)

    Sivakumar Venkatachalam

    2011-09-01

    Full Text Available Many experiments have been conducted to study the hydrodynamic characteristics of column reactors and loop reactors. In this present work, a novel combined loop airlift fluidized bed reactor was developed to study the effect of superficial gas and liquid velocities, particle diameter, fluid properties on gas holdup by using Newtonian and non-Newtonian liquids. Compressed air was used as gas phase. Water, 5% n-butanol, various concentrations of glycerol (60 and 80% were used as Newtonian liquids, and different concentrations of carboxy methyl cellulose aqueous solutions (0.25, 0.6 and 1.0% were used as non-Newtonian liquids. Different sizes of spheres, Bearl saddles and Raschig rings were used as solid phases. From the experimental results, it was found that the increase in superficial gas velocity increases the gas holdup, but it decreases with increase in superficial liquid velocity and viscosity of liquids. Based on the experimental results a correlation was developed to predict the gas hold-up for Newtonian and non-Newtonian liquids for a wide range of operating conditions at a homogeneous flow regime where the superficial gas velocity is approximately less than 5 cm/s

  9. SDSS-IV MaNGA: What Shapes the Distribution of Metals in Galaxies? Exploring the Roles of the Local Gas Fraction and Escape Velocity

    Science.gov (United States)

    Barrera-Ballesteros, J. K.; Heckman, T.; Sánchez, S. F.; Zakamska, N. L.; Cleary, J.; Zhu, G.; Brinkmann, J.; Drory, N.; THE MaNGA TEAM

    2018-01-01

    We determine the local metallicity of the ionized gas for more than 9.2 × 105 star-forming regions (spaxels) located in 1023 nearby galaxies included in the Sloan Digital Sky Survey-IV MaNGA integral field spectroscopy unit survey. We use the dust extinction derived from the Balmer decrement and the stellar template fitting in each spaxel to estimate the local gas and stellar mass densities, respectively. We also use the measured rotation curves to determine the local escape velocity (V esc). We then analyze the relationships between the local metallicity and both the local gas fraction (μ) and V esc. We find that metallicity decreases with both increasing μ and decreasing V esc. By examining the residuals in these relations we show that the gas fraction plays a more primary role in the local chemical enrichment than does V esc. We show that the gas-regulator model of chemical evolution provides a reasonable explanation of the metallicity on local scales. The best-fit parameters for this model are consistent with the metal loss caused by momentum-driven galactic outflows. We also argue that both the gas fraction and the local escape velocity are connected to the local stellar surface density, which in turn is a tracer of the epoch at which the dominant local stellar population formed.

  10. The role of clusters in gas-solids reactors. An experimental study.

    NARCIS (Netherlands)

    Venderbosch, R.H.

    1998-01-01

    This PhD-work is meant to determine the contact efficiency experimentally for fluidization of fine particles over a wide range of superficial gas velocities (dp<200 mm and 0.1

  11. The Influences of Time and Velocity of Inert Gas on the Quality of theProcessing Product of Graphite Matrix on the Baking Step

    International Nuclear Information System (INIS)

    Imam-Dahroni; Dwi-Herwidhi; NS, Kasilani

    2000-01-01

    The research of the synthesis of matrix graphite on the step of bakingprocess was conducted, by focusing on the influence of time and velocityvariables of the inert gas. The investigation on baking times ranging from 5minutes to 55 minutes and by varying the velocity of inert gas from 0.30l/minute to 3.60 l/minute, resulted the product of different matrix.Optimizing at the time of operation and the flow rate of argon gas indicatedthat the baking time for 30 minutes and by the flow rate of argon gas of 2.60l/minute resulted best matrix graphite that has a hardness value of 11kg/mm 2 of hardness and the ductility of 1800 Newton. (author)

  12. Identifying the morphologies of gas hydrate distribution using P-wave velocity and density: a test from the GMGS2 expedition in the South China Sea

    Science.gov (United States)

    Liu, Tao; Liu, Xuewei

    2018-06-01

    Pore-filling and fracture-filling are two basic distribution morphologies of gas hydrates in nature. A clear knowledge of gas hydrate morphology is important for better resource evaluation and exploitation. Improper exploitation may cause seafloor instability and exacerbate the greenhouse effect. To identify the gas hydrate morphologies in sediments, we made a thorough analysis of the characteristics of gas hydrate bearing sediments (GHBS) based on rock physics modeling. With the accumulation of gas hydrate in sediments, both the velocities of two types of GHBS increase, and their densities decrease. Therefore, these two morphologies cannot be differentiated only by velocity or density. After a series of tests, we found the attribute ρ {{V}{{P}}}0.5 as a function of hydrate concentration show opposite trends for these two morphologies due to their different formation mechanisms. The morphology of gas hydrate can thus be identified by comparing the measured ρ {{V}{{P}}}0.5 with its background value, which means the ρ {{V}{{P}}}0.5 of the hydrate-free sediments. In 2013, China’s second gas hydrate expedition was conducted by Guangzhou Marine Geologic Survey to explore gas hydrate resources in the northern South China Sea, and both two hydrate morphologies were recovered. We applied this method to three sites, which include two pore-filling and three fracture-filling hydrate layers. The data points, that agree with the actual situations, account for 72% and 82% of the total for the two pore-filling hydrate layers, respectively, and 86%, 74%, and 69% for the three fracture-filling hydrate layers, respectively.

  13. P-Wave and S-Wave Velocity Structure of Submarine Landslide Associated With Gas Hydrate Layer on Frontal Ridge of Northern Cascadia Margin

    Science.gov (United States)

    He, T.; Lu, H.; Yelisetti, S.; Spence, G.

    2015-12-01

    The submarine landslide associated with gas hydrate is a potential risk for environment and engineering projects, and thus from long time ago it has been a hot topic of hydrate research. The study target is Slipstream submarine landslide, one of the slope failures observed on the frontal ridges of the Northern Cascadia accretionary margin off Vancouver Island. The previous studies indicated a possible connection between this submarine landslide feature and gas hydrate, whose occurrence is indicated by a prominent bottom-simulating reflector (BSR), at a depth of ~265-275 m beneath the seafloor (mbsf). The OBS (Ocean Bottom Seismometer) data collected during SeaJade (Seafloor Earthquake Array - Japan Canada Cascadia Experiment) project were used to derive the subseafloor velocity structure for both P- and S-wave using travel times picked from refraction and reflection events. The P-wave velocity structure above the BSR showed anomalous high velocities of about 2.0 km/s at shallow depths of 100 mbsf, closely matching the estimated depth of the glide plane (100 ± 10 m). Forward modelling of S-waves was carried out using the data from the OBS horizontal components. The S-wave velocities, interpreted in conjunction with the P-wave results, provide the key constraints on the gas hydrate distribution within the pores. The hydrate distribution in the pores is important for determining concentrations, and also for determining the frame strength which is critical for controlling slope stability of steep frontal ridges. The increase in S-wave velocity suggests that the hydrate is distributed as part of the load-bearing matrix to increase the rigidity of the sediment.

  14. Propagation velocity of an avalanche along the anode wire in a Geiger-Mueller counter filled with Q-gas at 1 ATM

    International Nuclear Information System (INIS)

    Matsuda, Kazunori; Sanada, Junpei

    1990-01-01

    Simple methods were applied to investigate the characteristics of a Geiger-Mueller counter with Q-gas flowing at 1 atm. The propagation velocity of the photon-aided avalanche along the anode wire depends linearly on the strength of the electric field in the counter. Its fluctuation (FWHM) as a function of distance between the source position and the end point is discussed. (orig.)

  15. Velocity and AVO analysis for the investigation of gas hydrate along a profile in the western continental margin

    Digital Repository Service at National Institute of Oceanography (India)

    Dewangan, P.; Ramprasad, T.

    The occurrence of gas hydrate has been inferred from the presence of Bottom-Simulating Reflectors (BSRs) along the western continental margin of India. In this paper, we assess the spatial and vertical distribution of gas hydrates by analyzing...

  16. Statistic characteristics of the gas-liquid flow in a vertical minichannel

    Science.gov (United States)

    Kozulin, I. A.; Kuznetsov, V. V.

    2010-03-01

    The gas-liquid upward flow was studied in a rectangular minichannel of 1.75×3.8 mm and length of 0.7 m. The experiments were carried out within the range of the gas superficial velocity from 0.1 to 10 m/s and the liquid superficial velocity from 0.07 to 0.7 m/s for the co-current H2O/CO2 flow under the conditions of saturation. The method for the two-beam laser scanning of structure and determination of statistic characteristics of the two-phase flow was worked through. The slug-bubble, slug, transitional, churn, and annular flows were distinguished. The statistics characteristics of liquid and gas phases motion in a minichannel were obtained for the first time including the velocities of phase motion.

  17. Superficial Priming in Episodic Recognition

    Science.gov (United States)

    Dopkins, Stephen; Sargent, Jesse; Ngo, Catherine T.

    2010-01-01

    We explored the effect of superficial priming in episodic recognition and found it to be different from the effect of semantic priming in episodic recognition. Participants made recognition judgments to pairs of items, with each pair consisting of a prime item and a test item. Correct positive responses to the test item were impeded if the prime…

  18. Superficial parotidectomy via facelift incision

    NARCIS (Netherlands)

    Lohuis, Peter J. F. M.; Tan, M. Liane; Bonte, Katrien; van den Brekel, Michiel W. M.; Balm, Alfons J. M.; Vermeersch, Hubert B.

    2009-01-01

    The stigma of a visually prominent facial scar following parotid surgery can be distressing to a young patient. The surgical technique of parotidectomy via a facelift incision is described and evaluated. Thirty patients with a benign lesion of the parotid gland underwent a partial superficial

  19. SDSS IV MaNGA—Rotation Velocity Lags in the Extraplanar Ionized Gas from MaNGA Observations of Edge-on Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Bizyaev, D.; Pan, K.; Brinkmann, J. [Apache Point Observatory and New Mexico State University, Sunspot, NM 88349 (United States); Walterbos, R. A. M. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Yoachim, P. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Riffel, R. A. [Departamento de Física, CCNE, Universidade Federal de Santa Maria, Av. Roraima, 1000-97105-900, Santa Maria, RS (Brazil); Fernández-Trincado, J. G. [Institut Utinam, CNRS UMR 6213, Université de Franche-Comté, OSU THETA Franche-Comté-Bourgogne, Observatoire de Besançon, BP 1615, F-25010 Besançon Cedex (France); Diamond-Stanic, A. M. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Jones, A. [Max-Planck Institute for Astrophysics, Karl-Schwarzschild-Str 1, Garching, D-85748 (Germany); Thomas, D. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX (United Kingdom); Cleary, J. [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2017-04-20

    We present a study of the kinematics of the extraplanar ionized gas around several dozen galaxies observed by the Mapping of Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We considered a sample of 67 edge-on galaxies out of more than 1400 extragalactic targets observed by MaNGA, in which we found 25 galaxies (or 37%) with regular lagging of the rotation curve at large distances from the galactic midplane. We model the observed H α emission velocity fields in the galaxies, taking projection effects and a simple model for the dust extinction into account. We show that the vertical lag of the rotation curve is necessary in the modeling, and estimate the lag amplitude in the galaxies. We find no correlation between the lag and the star formation rate in the galaxies. At the same time, we report a correlation between the lag and the galactic stellar mass, central stellar velocity dispersion, and axial ratio of the light distribution. These correlations suggest a possible higher ratio of infalling-to-local gas in early-type disk galaxies or a connection between lags and the possible presence of hot gaseous halos, which may be more prevalent in more massive galaxies. These results again demonstrate that observations of extraplanar gas can serve as a potential probe for accretion of gas.

  20. SDSS IV MaNGA—Rotation Velocity Lags in the Extraplanar Ionized Gas from MaNGA Observations of Edge-on Galaxies

    International Nuclear Information System (INIS)

    Bizyaev, D.; Pan, K.; Brinkmann, J.; Walterbos, R. A. M.; Yoachim, P.; Riffel, R. A.; Fernández-Trincado, J. G.; Diamond-Stanic, A. M.; Jones, A.; Thomas, D.; Cleary, J.

    2017-01-01

    We present a study of the kinematics of the extraplanar ionized gas around several dozen galaxies observed by the Mapping of Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We considered a sample of 67 edge-on galaxies out of more than 1400 extragalactic targets observed by MaNGA, in which we found 25 galaxies (or 37%) with regular lagging of the rotation curve at large distances from the galactic midplane. We model the observed H α emission velocity fields in the galaxies, taking projection effects and a simple model for the dust extinction into account. We show that the vertical lag of the rotation curve is necessary in the modeling, and estimate the lag amplitude in the galaxies. We find no correlation between the lag and the star formation rate in the galaxies. At the same time, we report a correlation between the lag and the galactic stellar mass, central stellar velocity dispersion, and axial ratio of the light distribution. These correlations suggest a possible higher ratio of infalling-to-local gas in early-type disk galaxies or a connection between lags and the possible presence of hot gaseous halos, which may be more prevalent in more massive galaxies. These results again demonstrate that observations of extraplanar gas can serve as a potential probe for accretion of gas.

  1. SDSS IV MaNGA—Rotation Velocity Lags in the Extraplanar Ionized Gas from MaNGA Observations of Edge-on Galaxies

    Science.gov (United States)

    Bizyaev, D.; Walterbos, R. A. M.; Yoachim, P.; Riffel, R. A.; Fernández-Trincado, J. G.; Pan, K.; Diamond-Stanic, A. M.; Jones, A.; Thomas, D.; Cleary, J.; Brinkmann, J.

    2017-04-01

    We present a study of the kinematics of the extraplanar ionized gas around several dozen galaxies observed by the Mapping of Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We considered a sample of 67 edge-on galaxies out of more than 1400 extragalactic targets observed by MaNGA, in which we found 25 galaxies (or 37%) with regular lagging of the rotation curve at large distances from the galactic midplane. We model the observed Hα emission velocity fields in the galaxies, taking projection effects and a simple model for the dust extinction into account. We show that the vertical lag of the rotation curve is necessary in the modeling, and estimate the lag amplitude in the galaxies. We find no correlation between the lag and the star formation rate in the galaxies. At the same time, we report a correlation between the lag and the galactic stellar mass, central stellar velocity dispersion, and axial ratio of the light distribution. These correlations suggest a possible higher ratio of infalling-to-local gas in early-type disk galaxies or a connection between lags and the possible presence of hot gaseous halos, which may be more prevalent in more massive galaxies. These results again demonstrate that observations of extraplanar gas can serve as a potential probe for accretion of gas.

  2. A galactic disk as a two-fluid system: Consequences for the critical stellar velocity dispersion and the formation of condensations in the gas

    International Nuclear Information System (INIS)

    Jog, C.J.; Solomon, P.M.

    1984-01-01

    We examine the consequences of treating a galactic disk as a two-fluid system for the stability of the entire disk and for the stability and form of the gas in the disk. We find that the existence of even a small fraction of the total disk surface density in a cold fluid (that is, the gas) makes it much harder to stabilize the entire two-fluid disk. (C/sub s/,min)/sub 2-f/, the critical stellar velocity dispersion for a two-fluid disk in an increasing function of μ/sub g//μ/sub s/, the gas fraction, and μ/sub t//kappa, where μ/sub g/, μ/sub s/, and μ/sub t/ are the gaseous, stellar, and total disk surface densities and kappa is the epicyclic frequency. In the Galaxy, we find that (C/sub s/,min)/sub 2-f/ as a function of R peaks when μ/sub t//kappa peaks-at galactocentric radii of Rapprox.5-7 kpc; two-fluid instabilities are most likely to occur in this region. This region is coincident with the peak in the molecular cloud distribution in the Galaxy. At the higher effective gas density resulting from the growth of a two-fluid instability, the gas may become unstble, even when originally the gas by itself is stable. The wavelength of a typical (induced) gas instability in the inner galaxy is approx.400 pc, and it contains approx.10 7 M/sub sun/ of interstellar matter; these instabilities may be identified with clusters of giant molecular clouds. We suggest that many of the spiral features seen in gas-rich spiral galaxies may be material arms or arm segments resulting from sheared two-fluid gravitational instabilities. The analysis presented here is applicable to any general disk galaxy consisting of stars and gas

  3. MHD free convection flow of a visco-elastic (Kuvshiniski type dusty gas through a semi infinite plate moving with velocity decreasing exponentially with time and radiative heat transfer

    Directory of Open Access Journals (Sweden)

    Om Prakash

    2011-06-01

    Full Text Available The present paper is concerned with the study of MHD free convective flow of a visco-elastic (Kuvshinski type dusty gas through a porous medium induced by the motion of a semi-infinite flat plate under the influence of radiative heat transfer moving with velocity decreasing exponentially with time. The expressions for velocity distribution of a dusty gas and dust particles, concentration profile and temperature field are obtained. The effect of Schmidt number (Sc, Magnetic field parameter (M and Radiation parameter (N on velocity distribution of dusty gas and dust particles, concentration and temperature distribution are discussed graphically.

  4. Laminar burning velocity and Markstein length of nitrogen diluted natural gas/hydrogen/air mixtures at normal, reduced and elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Haiyan [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China); Institute of High Performance Computing, A-star (Singapore); Ji, Min; Jiao, Qi; Huang, Qian; Huang, Zuohua [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China)

    2009-04-15

    Flame propagation of premixed nitrogen diluted natural gas/hydrogen/air mixtures was studied in a constant volume combustion bomb under various initial pressures. Laminar burning velocities and Markstein lengths were obtained for the diluted stoichiometric fuel/air mixtures with different hydrogen fractions and diluent ratios under various initial pressures. The results showed that both unstretched flame speed and unstretched burning velocity are reduced with the increase in initial pressure (except when the hydrogen fraction is 80%) as well as diluent ratio. The velocity reduction rate due to diluent addition is determined mainly by hydrogen fraction and diluent ratio, and the effect of initial pressure is negligible. Flame stability was studied by analyzing Markstein length. It was found that the increase of initial pressure and hydrogen fraction decreases flame stability and the flame tends to be more stable with the addition of diluent gas. Generally speaking, Markstein length of a fuel with low hydrogen fraction is more sensitive to the change of initial pressure than that of a one with high hydrogen fraction. (author)

  5. Thermodynamic measurement of the sound velocity of a Bose gas across the transition to Bose–Einstein condensation

    Science.gov (United States)

    Fritsch, A. R.; Tavares, P. E. S.; Vivanco, F. A. J.; Telles, G. D.; Bagnato, V. S.; Henn, E. A. L.

    2018-05-01

    We present an alternative method for determining the sound velocity in atomic Bose–Einstein condensates, based on thermodynamic global variables. The total number of trapped atoms was as a function of temperature carefully studied across the phase transition, at constant volume. It allowed us to evaluate the sound velocity resulting in consistent values from the quantum to classical regime, in good agreement with previous results found in literature. We also provide some insight about the dominant sound mode (thermal or superfluid) across a wide temperature range.

  6. Velocity of a single gas plug rising through a particle-gas-liquid three-phase flow (In the case that particles updrift in a stagnant liquid column)

    International Nuclear Information System (INIS)

    Koizumi, Yasuo; Shimada, Jun; Ohtake, Hiroyasu

    1999-01-01

    The velocity of a single air plug rising through a stagnant water column in a pipe with updrifting particles has been examined at atmospheric pressure and room temperature. The particles used were polymer balls with a diameter of 3.18 mm and a density of 0.835 x 10 -3 kg/m 3 . The water velocity in a film around the plug and a wake region behind the plug was measured by a laser Doppler velocimeter. The thickness of the film was also measured with a dye-fluoresce-method by a laser ray. When the updrifting particles were introduced, the rising velocity of the plug became fast a little. However, the velocity was considerably slower than that in the falling particle case and independent on the particle introduction rate. The film around the plug was thicker a little than that in the no particle case, however considerably thinner than that in the falling particle case. The water velocity in the film around the plug was slower a little than that in the no particle case, and not dependent on the particle introduction rate contrary to that in the falling particle case. The vortex size behind the plug was almost the same as that in the no particle case although the vortex region was spread downward in the falling particle case. (author)

  7. Superficie

    OpenAIRE

    Corna, Pablo María

    2015-01-01

    En la época posclásica del derecho romano se buscó, por parte del Estado y ciudadanos, utilizar ciertos terrenos que formaban parte de su patrimonio para arrendarlos por largo término —y a veces a perpetuidad— a personas que tenían el derecho de edificar o plantar mediante el pago de un precio llamado pensio o solárium. En el siglo II de nuestra era ya era utilizado para asentar tribus romanizadas en la frontera del imperio como para el cultivo de vid y los olivos que demoran varios años e...

  8. Improving estimations of greenhouse gas transfer velocities by atmosphere-ocean couplers in Earth-System and regional models

    Science.gov (United States)

    Vieira, V. M. N. C. S.; Sahlée, E.; Jurus, P.; Clementi, E.; Pettersson, H.; Mateus, M.

    2015-09-01

    Earth-System and regional models, forecasting climate change and its impacts, simulate atmosphere-ocean gas exchanges using classical yet too simple generalizations relying on wind speed as the sole mediator while neglecting factors as sea-surface agitation, atmospheric stability, current drag with the bottom, rain and surfactants. These were proved fundamental for accurate estimates, particularly in the coastal ocean, where a significant part of the atmosphere-ocean greenhouse gas exchanges occurs. We include several of these factors in a customizable algorithm proposed for the basis of novel couplers of the atmospheric and oceanographic model components. We tested performances with measured and simulated data from the European coastal ocean, having found our algorithm to forecast greenhouse gas exchanges largely different from the forecasted by the generalization currently in use. Our algorithm allows calculus vectorization and parallel processing, improving computational speed roughly 12× in a single cpu core, an essential feature for Earth-System models applications.

  9. Average energy expended per ion pair, exciton enhanced ionization (Jesse effect), electron drift velocity, average electron energy and scintillation in rare gas liquids

    International Nuclear Information System (INIS)

    Doke, T.; Hitachi, A.; Hoshi, Y.; Masuda, K.; Hamada, T.

    1977-01-01

    Precise measurements of W-values, the average energy expended per electron-hole pair in liquid Ar and Xe, were made by the electron-pulse method, and that in liquid Kr by the steady conduction current method. The results showed that the W-values were clearly smaller than those in gaseous Ar, Xe and Kr as predicted by Doke. The results can be explained by the conduction bands which exist in these rare gas liquids as well as in the solid state. The enhanced ionization yield was observed for Xe-doped liquid Ar, and it was attributed to the ionizing excitation transfer process from Ar excitons to doped Xe. This is very similar to the Jesse effect in the gas phase. The saturated value of the enhanced ionization was in good agreement with the theoretical value, and it provides strong evidence for the existence of the exciton states in liquid Ar. Fano factors in liquid Ar, Kr, Xe and Xe-doped liquid Ar have been estimated from the Fano Formula, and they were smaller than those in the gas phase. The drift velocity of electrons in liquid Ar, liquid Ar-gas mixtures and liquid Xe have been measured with gridded ionization chambers. The average electron energy in liquid Ar has been measured. The electron-induced scintillations of liquid Xe and Ar have been studied. (Kato, T.)

  10. Esophagectomy for Superficial Esophageal Neoplasia.

    Science.gov (United States)

    Watson, Thomas J

    2017-07-01

    Endoscopic therapies have become the standard of care for most cases of Barrett's esophagus with high-grade dysplasia or intramucosal adenocarcinoma. Despite a rapid and dramatic evolution in treatment paradigms, esophagectomy continues to occupy a place in the therapeutic armamentarium for superficial esophageal neoplasia. The managing physician must remain cognizant of the limitations of endoscopic approaches and consider surgical resection when they are exceeded. Esophagectomy, performed at experienced centers for appropriately selected patients with early-stage disease can be undertaken with the expectation of cure as well as low mortality, acceptable morbidity, and good long-term quality of life. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Hypocenter relocation of microseismic events using a 3-D velocity model of the shale-gas production site in the Horn River Basin

    Science.gov (United States)

    Woo, J. U.; Kim, J. H.; Rhie, J.; Kang, T. S.

    2016-12-01

    Microseismic monitoring is a crucial process to evaluate the efficiency of hydro-fracking and to understand the development of fracture networks. Consequently, it can provide valuable information for designing the post hydro-fracking stages and estimating the stimulated rock volumes. The fundamental information is a set of source parameters of microseismic events. The most important parameter is the hypocenter of event, and thus the accurate hypocenter determination is a key for the successful microseismic monitoring. The accuracy of hypocenters for a given dataset of seismic phase arrival times is dependent on that of the velocity model used in the seismic analysis. In this study, we evaluated how a 3-D model can affect the accuracy of hypocenters. We used auto-picked P- and S-wave travel-time data of about 8,000 events at the commercial shale gas production site in the Horn River Basin, Canada. The initial hypocenters of the events were determined using a single-difference linear inversion algorithm with a 1-D velocity model obtained from the well-logging data. Then we iteratively inverted travel times of events for the 3-D velocity perturbations and relocated their hypocenters using double-difference algorithm. Significant reduction of the errors in the final hypocenter was obtained. This result indicates that the 3-D model is useful for improving the performance of microseismic monitoring.

  12. Friends of hot Jupiters. I. A radial velocity search for massive, long-period companions to close-in gas giant planets

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, Heather A.; Ngo, Henry; Johnson, John Asher [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Fulton, Benjamin J.; Howard, Andrew W. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI (United States); Montet, Benjamin T.; Kao, Melodie; Hinkley, Sasha; Morton, Timothy D.; Muirhead, Philip S. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, Notre Dame, IN (United States); Bakos, Gaspar Á. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ (United States); Batygin, Konstantin, E-mail: hknutson@caltech.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2014-04-20

    In this paper we search for distant massive companions to known transiting gas giant planets that may have influenced the dynamical evolution of these systems. We present new radial velocity observations for a sample of 51 planets obtained using the Keck HIRES instrument, and find statistically significant accelerations in fifteen systems. Six of these systems have no previously reported accelerations in the published literature: HAT-P-10, HAT-P-22, HAT-P-29, HAT-P-32, WASP-10, and XO-2. We combine our radial velocity fits with Keck NIRC2 adaptive optics (AO) imaging data to place constraints on the allowed masses and orbital periods of the companions responsible for the detected accelerations. The estimated masses of the companions range between 1-500 M {sub Jup}, with orbital semi-major axes typically between 1-75 AU. A significant majority of the companions detected by our survey are constrained to have minimum masses comparable to or larger than those of the transiting planets in these systems, making them candidates for influencing the orbital evolution of the inner gas giant. We estimate a total occurrence rate of 51% ± 10% for companions with masses between 1-13 M {sub Jup} and orbital semi-major axes between 1-20 AU in our sample. We find no statistically significant difference between the frequency of companions to transiting planets with misaligned or eccentric orbits and those with well-aligned, circular orbits. We combine our expanded sample of radial velocity measurements with constraints from transit and secondary eclipse observations to provide improved measurements of the physical and orbital characteristics of all of the planets included in our survey.

  13. THE EVOLUTION OF GAS CLOUDS FALLING IN THE MAGNETIZED GALACTIC HALO: HIGH-VELOCITY CLOUDS (HVCs) ORIGINATED IN THE GALACTIC FOUNTAIN

    International Nuclear Information System (INIS)

    Kwak, Kyujin; Shelton, Robin L.; Raley, Elizabeth A.

    2009-01-01

    In the Galactic fountain scenario, supernovae and/or stellar winds propel material into the Galactic halo. As the material cools, it condenses into clouds. By using FLASH three-dimensional magnetohydrodynamic simulations, we model and study the dynamical evolution of these gas clouds after they form and begin to fall toward the Galactic plane. In our simulations, we assume that the gas clouds form at a height of z = 5 kpc above the Galactic midplane, then begin to fall from rest. We investigate how the cloud's evolution, dynamics, and interaction with the interstellar medium (ISM) are affected by the initial mass of the cloud. We find that clouds with sufficiently large initial densities (n ≥ 0.1 H atoms cm -3 ) accelerate sufficiently and maintain sufficiently large column densities as to be observed and identified as high-velocity clouds (HVCs) even if the ISM is weakly magnetized (1.3 μG). However, the ISM can provide noticeable resistance to the motion of a low-density cloud (n ≤ 0.01 H atoms cm -3 ) thus making it more probable that a low-density cloud will attain the speed of an intermediate-velocity cloud rather than the speed of an HVC. We also investigate the effects of various possible magnetic field configurations. As expected, the ISM's resistance is greatest when the magnetic field is strong and perpendicular to the motion of the cloud. The trajectory of the cloud is guided by the magnetic field lines in cases where the magnetic field is oriented diagonal to the Galactic plane. The model cloud simulations show that the interactions between the cloud and the ISM can be understood via analogy to the shock tube problem which involves shock and rarefaction waves. We also discuss accelerated ambient gas, streamers of material ablated from the clouds, and the cloud's evolution from a sphere-shaped to a disk- or cigar-shaped object.

  14. An experimental study of the velocity-forced flame response of a lean-premixed multi-nozzle can combustor for gas turbines

    Science.gov (United States)

    Szedlmayer, Michael Thomas

    The velocity forced flame response of a multi-nozzle, lean-premixed, swirl-stabilized, turbulent combustor was investigated at atmospheric pressure. The purpose of this study was to analyze the mechanisms that allowed velocity fluctuations to cause fluctuations in the rate of heat release in a gas turbine combustor experiencing combustion instability. Controlled velocity fluctuations were introduced to the combustor by a rotating siren device which periodically allowed the air-natural gas mixture to flow. The velocity fluctuation entering the combustor was measured using the two-microphone method. The resulting heat release rate fluctuation was measured using CH* chemiluminescence. The global response of the flame was quantified using the flame transfer function with the velocity fluctuation as the input and the heat release rate fluctuation as the output. Velocity fluctuation amplitude was initially maintained at 5% of the inlet velocity in order to remain in the linear response regime. Flame transfer function measurements were acquired at a wide range of operating conditions and forcing frequencies. The selected range corresponds to the conditions and instability frequencies typical of real gas turbine combustors. Multi-nozzle flame transfer functions were found to bear a qualitative similarity to the single-nozzle flame transfer functions in the literature. The flame transfer function gain exhibited alternating minima and maxima while the phase decreased linearly with increasing forcing frequency. Several normalization techniques were applied to all flame transfer function data in an attempt to collapse the data into a single curve. The best collapse was found to occur using a Strouhal number which was the ratio of the characteristic flame length to the wavelength of the forced disturbance. Critical values of Strouhal number are used to predict the shedding of vortical structures in shear layers. Because of the collapse observed when the flame transfer functions

  15. Velocity Structure and 3D Finite Element Modeling for Critical Instability of Gas Hydrate-related Slipstream Submarine Slide, offshore Vancouver Island, Canada

    Science.gov (United States)

    LONG, S.; He, T.; Lan, K.; Spence, G.; Yelisetti, S.

    2016-12-01

    The previous study indicated that Slipstream submarine landslide is one of a gas hydrate-related slope failures on the frontal ridges of the Northern Cascadia accretionary margin, off Vancouver Island, Canada. The OBS data collected during SeaJade project were used to derive the subseafloor Vp & Vs structures. The anomalous high Vp of about 2.0 km/s at shallow depths of 100 (± 10) mbsf closely matches the estimated depth of the glide plane. The modelled Vs above the BSR at a depth of 265-275 mbsf is about 100-150 m/s higher than a theoretical 100% water saturated background value, indicating that the hydrate acts as part of the load-bearing matrix to increase the rigidity of the sediment. Also, the Vp & Vs above BSR both indicate a consistent 40% saturation of gas hydrate. On the basis of high accurate submarine bathymetry obtained by multibeam sounding system, the submarine landform before slump is reconstructed by comparing the slump headwall geometry with surrounding ridges. Using the elastic moduli determined from Vp & Vs, the stress status was calculated by the finite element method for different conditions and confirmed that the undersea sliding process related with gas hydrate starts from the toe of the slope and then progressively retreats to the place of current headwall, in a series of triangular blocks or wedges. The shear stress are then compared with the frame shear strength of geological model, which is critical for controlling slope stability of steep frontal ridges The simulation results found that the ridge was stable under its own weight, but gas hydrate saturation decrease and pore-water pressure increase will greatly reduce shear strength of sediments and may cause a landslide. Since the study area is in the earthquake belt, the large seismic acceleration will greatly affect pore pressure distribution within the ridge. The simulation results indicated that the shallow high-velocity gas hydrate layer coincident with glide plane depth is more

  16. Effect of geometric parameters of liquid-gas separator units on phase separation performance

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Songping; Chen, Xueqing; Chen, Ying [Guangdong University of Technology, Seoul (China); Yang, Zhen [Tsinghua University, Beijing (China)

    2015-07-15

    Five liquid-gas separator units were designed and constructed based on a new concept of a validated high-performance condenser. Each separator unit consists of two united T-junctions and an apertured baffle. The separator units have different header diameters or different baffles with different diameters of the liquid-gas separation hole. The phase separation characteristics of the units were investigated at inlet air superficial velocities from 1.0m/s to 33.0m/s and water superficial velocities from 0.0015 m/s to 0..50 m/s. The experimental results showed that the liquid height, liquid flow rate through the separation hole, and liquid separation efficiency increased with increased header diameter and decreased diameter of the separation hole. The geometric structures of the separator units affected the phase separation characteristics by influencing the liquid height in the header and the liquid flow rate through the separation hole.

  17. Visualization for gas-liquid two-phase flow using wire mesh tomography

    International Nuclear Information System (INIS)

    Motegi, Yuichi; Wanjiraniran, Weerin; Kikura, Hiroshige; Aritomi, Masanori; Yamauchi, Toyoaki

    2003-01-01

    Wire Mesh Tomography (WMT), which is system to measure two-phase flow, has been developed in our laboratory. Measurement principle of WMT is detecting conductivity difference between gas and liquid. WMT measures void fraction as raw date, and calculates gas velocity and bubble volume etc. In this paper, this measurement technique was applied to vertical circular pipe of 50 mm diameter and about 7 m heights. New Wire Mesh Sensor (WMS), which is measurement part of WMT, for circular pipe, have been made. When experiment was performed, superficial gas and water velocity. The effect of each flow parameter was found for void fraction, true gas velocity and bubble volume and the results was in good agreement with the past research, qualitatively. (author)

  18. Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.; Johnson, I.

    1980-01-01

    Diatomaceous earth and activated bauxite were tested as granular sorbents for use as filter media in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800/sup 0/C) flue gas of PFBC. Tests were performed at atmospheric pressure, using NaCl vapor transported in relatively dry simulated flue gas of PFBC. Either a fixed-bed combustor or a high-temperature sorption test rig was used. The effects of sorbent bed temperature, superficial gas velocity, gas hourly space velocity, and NaCl-vapor concentration in flue gas on the sorption behavior of these two sorbents and their ultimate sorption capacities were determined. Both diatomaceous earth and activated bauxite were found to be very effective in removing NaCl vapor from flue gas. Preliminary cost evaluations showed that they are economically attractive as granular sorbents for cleaning alkali vapor from simulated flue gas.

  19. Scanning electron microscopy of superficial white onychomycosis*

    Science.gov (United States)

    de Almeida Jr., Hiram Larangeira; Boabaid, Roberta Oliveira; Timm, Vitor; Silva, Ricardo Marques e; de Castro, Luis Antonio Suita

    2015-01-01

    Superficial white onychomycosis is characterized by opaque, friable, whitish superficial spots on the nail plate. We examined an affected halux nail of a 20-year-old male patient with scanning electron microscopy. The mycological examination isolated Trichophyton mentagrophytes. Abundant hyphae with the formation of arthrospores were found on the nail's surface, forming small fungal colonies. These findings showed the great capacity for dissemination of this form of onychomycosis. PMID:26560225

  20. Local measurement of interfacial area, interfacial velocity and liquid turbulence in two-phase flow

    International Nuclear Information System (INIS)

    Hibiki, T.; Hogsett, S.; Ishii, M.

    1998-01-01

    Double sensor probe and hotfilm anemometry methods were developed for measuring local flow characteristics in bubbly flow. The formulation for the interfacial area concentration measurement was obtained by improving the formulation derived by Kataoka and Ishii. The assumptions used in the derivation of the equation were verified experimentally. The interfacial area concentration measured by the double sensor probe agreed well with one by the photographic method. The filter to validate the hotfilm anemometry for measuring the liquid velocity and turbulent intensity in bubbly flow was developed based on removing the signal due to the passing bubbles. The local void fraction, interfacial area concentration, interfacial velocity, Sauter mean diameter, liquid velocity, and turbulent intensity of vertical upward air-water flow in a round tube with inner diameter of 50.8 mm were measured by using these methods. A total of 54 data sets were acquired consisting of three superficial gas flow rates, 0.039, 0.067, and 0.147 m/s, and three superficial liquid flow rates, 0.60, 1.00, and 1.30 m/s. The measurements were performed at the three locations: L/D=2, 32, and 62. This data is expected to be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow. (author)

  1. The critical ionization velocity

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1980-06-01

    The critical ionization velocity effect was first proposed in the context of space plasmas. This effect occurs for a neutral gas moving through a magnetized plasma and leads to rapid ionization and braking of the relative motion when a marginal velocity, 'the critical velocity', is exceeded. Laboratory experiments have clearly established the significance of the critical velocity and have provided evidence for an underlying mechanism which relies on the combined action of electron impact ionization and a collective plasma interaction heating electrons. There is experimental support for such a mechanism based on the heating of electrons by the modified two-stream instability as part of a feedback process. Several applications to space plasmas have been proposed and the possibility of space experiments has been discussed. (author)

  2. A HIGH-PRECISION NEAR-INFRARED SURVEY FOR RADIAL VELOCITY VARIABLE LOW-MASS STARS USING CSHELL AND A METHANE GAS CELL

    Energy Technology Data Exchange (ETDEWEB)

    Gagné, Jonathan [Carnegie Institution of Washington DTM, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Plavchan, Peter [Department of Physics, Missouri State University, 901 S National Ave, Springfield, MO 65897 (United States); Gao, Peter [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Anglada-Escude, Guillem [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Rd, E1 4NS, London (United Kingdom); Furlan, Elise; Brinkworth, Carolyn; Ciardi, David R. [NASA Exoplanet Science Institute, California Institute of Technology, 770 S. Wilson Ave., Pasadena, CA 91125 (United States); Davison, Cassy; Henry, Todd J.; White, Russel [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Tanner, Angelle [Mississippi State University, Department of Physics and Astronomy, Hilbun Hall, Starkville, MS 39762 (United States); Riedel, Adric R. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Latham, David; Johnson, John A. [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Bottom, Michael [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Mills, Sean [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637 (United States); Beichman, Chas [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Wallace, Kent; Mennesson, Bertrand [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91125 (United States); Von Braun, Kaspar, E-mail: jgagne@carnegiescience.edu [Lowell Observatory, West Mars Hill Road, Flagstaff, AZ 86001 (United States); and others

    2016-05-01

    We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2–M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25–150 Myr) moving groups, the young field star ε Eridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8–15 m s{sup −1}with a long-term stability of 15–50 m s{sup −1} over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25–50 m s{sup −1} at ≈2.3125 μ m, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ 876 bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD 160934 AB and GJ 725 AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3 σ –5 σ . Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of ≲5 m s{sup −1} in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

  3. A HIGH-PRECISION NEAR-INFRARED SURVEY FOR RADIAL VELOCITY VARIABLE LOW-MASS STARS USING CSHELL AND A METHANE GAS CELL

    International Nuclear Information System (INIS)

    Gagné, Jonathan; Plavchan, Peter; Gao, Peter; Anglada-Escude, Guillem; Furlan, Elise; Brinkworth, Carolyn; Ciardi, David R.; Davison, Cassy; Henry, Todd J.; White, Russel; Tanner, Angelle; Riedel, Adric R.; Latham, David; Johnson, John A.; Bottom, Michael; Mills, Sean; Beichman, Chas; Wallace, Kent; Mennesson, Bertrand; Von Braun, Kaspar

    2016-01-01

    We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2–M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25–150 Myr) moving groups, the young field star ε Eridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8–15 m s −1 with a long-term stability of 15–50 m s −1 over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25–50 m s −1 at ≈2.3125 μ m, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ 876 bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD 160934 AB and GJ 725 AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3 σ –5 σ . Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of ≲5 m s −1 in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

  4. On linear relationship between shock velocity and particle velocity

    International Nuclear Information System (INIS)

    Dandache, H.

    1986-11-01

    We attempt to derive the linear relationship between shock velocity U s and particle velocity U p from thermodynamic considerations, taking into account an ideal gas equation of state and a Mie-Grueneisen equation of state for solids. 23 refs

  5. Effect of Gas- and Liquid-injection Methods on Formation of Bubble and Liquid Slug at Merging Micro T-junction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Kyoung [Kyungnam Univ., Changwon (Korea, Republic of); Lee, Chi Young [Pukyong Nat’l Univ., Busan (Korea, Republic of)

    2016-04-15

    In the present experimental study, the effect of gas- and liquid-injected methods on the formation of bubble and liquid slug at the merging micro T-junction of a square microchannel with dimensions 600 μm × 600 μm was investigated. Nitrogen and water were used as test fluids. The superficial velocities of the liquid and gas were in the range of 0.05 - 1 m/s, and 0.1 - 1 m/s, respectively, where the Taylor flow was observed. The bubble length, liquid slug length, bubble velocity, and bubble generation frequency were measured by analyzing the images captured using a high-speed camera. Under similar inlet superficial velocity conditions, in the case of gas injection to the main channel at the merging T-junction (T{sub g}as-liquid), the lengths of the bubble and liquid slug were longer, and the bubble generation frequency was lower than in the case of liquid injection to the main channel at the merging T-junction (T{sub l}iquid-gas). On the other hand, in both cases, the bubble velocity was almost the same. The previous correlation proposed using experimental data for T{sub l}iquid-gas had predicted the present experimental data of bubble length, bubble velocity, liquid slug length, and bubble generation frequency for T{sub g}as-liquid to be ~24%, ~9%, ~39%, ~55%, respectively.

  6. HIGH ORIGIN OF SUPERFICIAL ULNAR ARTERY- A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Anjana Jayakumaran Nair

    2017-03-01

    Full Text Available BACKGROUND High origin and superficially placed ulnar artery is a rare anatomical variant that usually arises either in the axilla or arm and runs a superficial course in the forearm, enters the hand and participates in the formation of superficial palmar arch. During routine dissection of cadavers in our department, we observed a unilateral case of high origin and superficial ulnar artery in a human male cadaver. It originated from the brachial artery in the lower third of arm 4 cm above its bifurcation. From its origin, it passed downwards along the medial aspect of forearm, superficial to the flexors, entered hand superficial to the flexor retinaculum and formed superficial palmar arch. The knowledge of existence of a superficial ulnar artery is important during vascular and reconstructive surgery and also in evaluation of angiographic images. Superficial position makes it more vulnerable to trauma and more accessible to cannulation.

  7. Intravesical Gemcitabine for Treatment of Superficial Bladder ...

    African Journals Online (AJOL)

    Objectives: Intravesical Bacillus Calmette-Guérin (BCG) vaccine is the mainstay of treatment and prophylaxis in superficial bladder cancer (SBC) as it reduces tumor recurrence and disease progression. About one-third of patients do not respond to BCG. The aim of this study was to determine the efficacy of intravesical ...

  8. [Superficial venous thrombosis. A state of art].

    Science.gov (United States)

    Sándor, Tamás

    2017-01-01

    For a long time superficial thrombophlebitis has been thought to be a rather benign condition. Recently, when duplex ultrasound technique is used for the diagnosis more and more often, the disease is proved to be more dangerous than anticipated. Thrombosis propagates to the deep veins in 6-44% and pulmonary embolism was observed on the patients in 1,5-33%. We can calculate venous thromboembolic complications on every fourth patient. Diagnosis is clinical, but duplex ultrasound examination is mandatory, for estimation of the thrombus extent, for exclusion of the deep venous thrombosis and for follow up. Both legs should be checked with ultrasound, because simultaneous deep venous thrombosis can develop on the contralateral limb. Two different forms can be distinguished: superficial venous thrombosis with, or without varicose veins. In cases of spontaneous, non varicous form, especially when the process is migrating or recurrent, a careful clinical examination is necessery for exclusion of malignant diseases and thrombophilia. The treatment options are summarised on the basis of recent international consensus statements. The American and German guidelines are similar. Compression and mobilisation are cornerstones of the therapy. For a short segment thrombosis non steroidal antiinflammatory drugs are effective. For longer segments low molecular-weight heparins are preferred. Information on the effect of the novel oral anticoagulants for the therapy is lacking but they may appear to be effective in the future for this indication. When thrombus is close to the sapheno-femoral or sapheno-popliteal junction crossectomy (high ligation), or low molecular-weight heparin in therapeutic doses are indicated. The term superficial thrombophlebitis should be discouraged, because inflammation and infection is not the primary pathology. It should be called correctly superficial venous thrombosis in order to avoid the unnecessary administration of antibiotics and the misconception

  9. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  10. Dryout characteristics and flow behavior of gas-water two-phase flow through U-shaped and inverted U-shaped bends

    International Nuclear Information System (INIS)

    Takemura, T.; Roko, K.; Shiraha, M.; Midoriyama, S.

    1986-01-01

    Experimental results are presented on the flow behavior, pressure drop characteristics, and dryout characteristics by joule heating for the gas-water flow through U-shaped and inverted U-shaped tubes invertical plane. The height of the vertical straight section of the test tube is 4100 mm, and two bend radii, 116 mm and 435 mm, are chosen for the experiments. The test tubes used are of transparent acrylic resin for the flow behavior test, and of stainless steel for the other tests, inside diameter being 18 mm for the former and 18.5 mm for the latter. Flow patterns in the vertical upflow and downflow sections are shown on the diagram of the superficial gas velocity versus liquid velocity. Further, the flow behavior in the bend section is made clear in relation to flow rates of gas and liquid. The pressure drop between inlet and outlet of the test tube for the made clear in relation to flow rates of gas and liquid. The pressure drop between inlet and outlet of the test tube for the two-phase flow is shown in comparison with that for the single-phase flow of water. The threshold conditions of dryout in the bend section by joule heatig are shown on the diagram of the superficial gas velocity versus liquid velocity. The location of the dryout in the bend section is also clarified. (orig.)

  11. Malignant transformation of superficial peritoneal endometriosis lesion.

    Science.gov (United States)

    Marchand, Eva; Hequet, Delphine; Thoury, Anne; Barranger, Emmanuel

    2013-08-26

    A 63-year-old woman with no medical history underwent an abdominal surgery with hysterectomy and bilateral salpingo-oophorectomy for a 10 cm peritoneal cyst with increased cancer antigene-125. A large suspicious tumour of the Douglas space, with contact to the uterus and the rectal wall was described. The rest of the exploration was normal, specially the rest of the peritoneum. Histopathology revealed a malignant transformation of a superficial peritoneal endometriosis. Secondary surgery was thus completed by laparoscopy with bilateral pelvic and para-aortic lymph node dissections, omentectomy and multiple peritoneal biopsies. All staging samples were free of cancer; therefore no complementary therapy was administered. After 18 months of follow-up, consisting of clinical examination and pelvis magnetic resonance imaging every 6 months, we did not observe any recurrence. Malignant transformation of superficial peritoneal endometriosis is a rare disease and surgical management seems to be the main treatment.

  12. Clinico Mycological Study of Superficial Mycoses

    Directory of Open Access Journals (Sweden)

    Rachana J. Magdum

    2016-10-01

    Full Text Available Background: Generally it is well established fact that geographical distribution of the fungi may change from time to time; hence this study was planned. Aim and Objectives: To analyze the prevalence of superficial mycoses, its clinical presentation and species identification of the fungal isolates responsible for the disease. Material and Methods: A total 125 clinically diagnosed cases of superficial mycoses visiting Dermatology and Venereology outpatient department of Bharati Hospital, Sangli, for a period of one year were included in the study. Specimens like skin scrapping, nail clipping, hair were collected and subjected to KOH mount and culture. Identification of species was done by macroscopic examination of culture, tease mount and other physiological tests including Urease test, Hair perforation tests and Germ tube test. Results: Superficial mycosis was more common in the age group of 21-30 years (28% and in males (60.8%. The infection was more common in students (29.6%. Tinea corporis (42.4% was the commonest clinical type followed by tinea cruris (22.4%. 61.6% cases were positive by direct microscopy and 60.8% cases showed culture positive. Out of 125 samples, dermatophytes were grown in 63 cases (82.89% followed by non dermatophytic moulds in 10 cases (13.16% and Candida albicans in 3 cases (3.95%. The most common isolate among dermtophytosis was T. rubrum (46.05% followed by T. mentagrophyte (25%. Conclusion: It was concluded that along with dermatophytes, non dermatophytic moulds are also important to cause of superficial mycoses

  13. Spectral characterization of superficial coal groups

    International Nuclear Information System (INIS)

    Ahmad, I.; Khan, M.A.; Ishaq, M.; Shakirullah; Bahadur, A.

    2004-01-01

    Spectral characterization of superficial coal groups was performed in KBr pellets. KBr Pellets were prepared for virgin and variously pretreated coal samples. Spectra of satisfactory resolution were obtained in wave number range-4000-400 cm /sup -1/. Presence of broad absorption bands corresponds to hydroxyl, carbonyl, carboxyl and phenolic functionalities in the spectra clearly define their presence in all samples understudy. Forced oxidation proved effective for oxidation of both aliphatic and aromatic configurations, which can be revealed from the respective spectra. (author)

  14. Volumetric and superficial characterization of carbon activated

    International Nuclear Information System (INIS)

    Carrera G, L.M.; Garcia S, I.; Jimenez B, J.; Solache R, M.; Lopez M, B.; Bulbulian G, S.; Olguin G, M.T.

    2000-01-01

    The activated carbon is the resultant material of the calcination process of natural carbonated materials as coconut shells or olive little bones. It is an excellent adsorbent of diluted substances, so much in colloidal form, as in particles form. Those substances are attracted and retained by the carbon surface. In this work is make the volumetric and superficial characterization of activated carbon treated thermically (300 Centigrade) in function of the grain size average. (Author)

  15. Gas dynamics in the inner few AU around the Herbig B[e] star MWC297. Indications of a disk wind from kinematic modeling and velocity-resolved interferometric imaging

    Science.gov (United States)

    Hone, Edward; Kraus, Stefan; Kreplin, Alexander; Hofmann, Karl-Heinz; Weigelt, Gerd; Harries, Tim; Kluska, Jacques

    2017-10-01

    Aims: Circumstellar accretion disks and outflows play an important role in star formation. By studying the continuum and Brγ-emitting region of the Herbig B[e] star MWC297 with high-spectral and high-spatial resolution we aim to gain insight into the wind-launching mechanisms in young stars. Methods: We present near-infrared AMBER (R = 12 000) and CRIRES (R = 100 000) observations of the Herbig B[e] star MWC297 in the hydrogen Brγ-line. Using the VLTI unit telescopes, we obtained a uv-coverage suitable for aperture synthesis imaging. We interpret our velocity-resolved images as well as the derived two-dimensional photocenter displacement vectors, and fit kinematic models to our visibility and phase data in order to constrain the gas velocity field on sub-AU scales. Results: The measured continuum visibilities constrain the orientation of the near-infrared-emitting dust disk, where we determine that the disk major axis is oriented along a position angle of 99.6 ± 4.8°. The near-infrared continuum emission is 3.6 × more compact than the expected dust-sublimation radius, possibly indicating the presence of highly refractory dust grains or optically thick gas emission in the inner disk. Our velocity-resolved channel maps and moment maps reveal the motion of the Brγ-emitting gas in six velocity channels, marking the first time that kinematic effects in the sub-AU inner regions of a protoplanetary disk could be directly imaged. We find a rotation-dominated velocity field, where the blue- and red-shifted emissions are displaced along a position angle of 24° ± 3° and the approaching part of the disk is offset west of the star. The visibility drop in the line as well as the strong non-zero phase signals can be modeled reasonably well assuming a Keplerian velocity field, although this model is not able to explain the 3σ difference that we measure between the position angle of the line photocenters and the position angle of the dust disk. We find that the fit can be

  16. Evaluation of a Candidate Trace Contaminant Control Subsystem Architecture: The High Velocity, Low Aspect Ratio (HVLA) Adsorption Process

    Science.gov (United States)

    Kayatin, Matthew J.; Perry, Jay L.

    2017-01-01

    Traditional gas-phase trace contaminant control adsorption process flow is constrained as required to maintain high contaminant single-pass adsorption efficiency. Specifically, the bed superficial velocity is controlled to limit the adsorption mass-transfer zone length relative to the physical adsorption bed; this is aided by traditional high-aspect ratio bed design. Through operation in this manner, most contaminants, including those with relatively high potential energy are readily adsorbed. A consequence of this operational approach, however, is a limited available operational flow margin. By considering a paradigm shift in adsorption architecture design and operations, in which flows of high superficial velocity are treated by low-aspect ratio sorbent beds, the range of well-adsorbed contaminants becomes limited, but the process flow is increased such that contaminant leaks or emerging contaminants of interest may be effectively controlled. To this end, the high velocity, low aspect ratio (HVLA) adsorption process architecture was demonstrated against a trace contaminant load representative of the International Space Station atmosphere. Two HVLA concept packaging designs (linear flow and radial flow) were tested. The performance of each design was evaluated and compared against computer simulation. Utilizing the HVLA process, long and sustained control of heavy organic contaminants was demonstrated.

  17. HISTOPATHOLOGY OF MARGINAL SUPERFICIAL PERIODONTIUM AT MENOPAUSE

    Directory of Open Access Journals (Sweden)

    A. Georgescu

    2012-03-01

    Full Text Available Premises: Sexual hormones may affect the general health condition of women, as early as puberty, continuing during pregnancy and also after menopause. Variations of the hormonal levels may cause different – either local or general – pathological modifications. Sexual hormones may also affect periodontal status, favourizing gingival inflammations and reducing periodontal resistance to the action of the bacterial plaque. Scope: Establishment of the correlations between the debut or the manifestation of menopause and the modifications produced in the superficial periodontium. Materials and method: Clinical and paraclinical investigations were performed on female patients with ages between 45 and 66 years, involving macroscopic, microscopic and radiological recording of the aspect of the superificial periodontium (gingiva. Results: Analysis of the histological sections evidenced atrophic and involutive modifications in the marginal superficial periodontium of female patients at menopause. Conclusions: Sexual hormones intervene in the histological equilibrium of the marginal superficial periodontium, influencing the periodontal health status, which explains the correlation between the subjective symptomatology specific to menopause and the histopatological aspect at epithelial level.

  18. Diagnosis and treatment of superficial esophageal cancer.

    Science.gov (United States)

    Barret, Maximilien; Prat, Frédéric

    2018-01-01

    Endoscopy allows for the screening, early diagnosis, treatment and follow up of superficial esophageal cancer. Endoscopic submucosal dissection has become the gold standard for the resection of superficial squamous cell neoplasia. Combinations of endoscopic mucosal resection and radiofrequency ablation are the mainstay of the management of Barrett's associated neoplasia. However, protruded, non-lifting or large lesions may be better managed by endoscopic submucosal dissection. Novel ablation tools, such as argon plasma coagulation with submucosal lifting and cryoablation balloons, are being developed for the treatment of residual Barrett's esophagus, since iatrogenic strictures still hamper the development of extensive circumferential resections in the esophagus. Optimal surveillance modalities after endoscopic resection are still to be determined. The assessment of the risk of lymph-node metastases, as well as of the need for additional treatments based on qualitative and quantitative histological criteria, balanced to the patient's condition, requires a dedicated multidisciplinary team decision process. The need for trained endoscopists, expert pathologists and surgeons, and specialized multidisciplinary meetings underlines the role of expert centers in the management of superficial esophageal cancer.

  19. A wind-tunnel study on exhaust gas dispersion from road vehicles. Part 1. Velocity and concentration fields behind single vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Kanda, Isao; Uehara, Kiyoshi; Yamao, Yukio [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 (Japan); Yoshikawa, Yasuo; Morikawa, Tazuko [Petroleum Energy Center, 4-3-9 Toranomon, Minato-ku, Tokyo, 105-0001 (Japan)

    2006-09-15

    By a reduced-scale model in a wind tunnel, we investigate the dispersion behavior of exhaust gas from automobiles. Two types of vehicles are considered, a passenger car and a small-size truck. Tracer gas experiments show that the exhaust gas dispersion is enhanced significantly by the vehicle wake compared to the case when the vehicle body is absent. The passenger car and the truck promote dispersion in the horizontal and the vertical direction, respectively. The wake field is analyzed by particle image velocimetry (PIV), and the distribution of the mean and the fluctuation fields is found to conform to the concentration field of the exhaust gas. The buoyancy of the exhaust gas has minor effect except on the vertical spread behind the truck whose wake flow amplifies the vertical displacement generated near the pipe exit. (author)

  20. Monthly dynamics of carbon dioxide exchange across the sea surface of the Arctic Ocean in response to changes in gas transfer velocity and partial pressure of CO2 in 2010

    Directory of Open Access Journals (Sweden)

    Iwona Wrobel

    2017-10-01

    Full Text Available The Arctic Ocean (AO is an important basin for global oceanic carbon dioxide (CO2 uptake, but the mechanisms controlling air–sea gas fluxes are not fully understood, especially over short and long timescales. The oceanic sink of CO2 is an important part of the global carbon budget. Previous studies have shown that in the AO differences in the partial pressure of CO2 (ΔpCO2 and gas transfer velocity (k both contribute significantly to interannual air–sea CO2 flux variability, but that k is unimportant for multidecadal variability. This study combined Earth Observation (EO data collected in 2010 with the in situ pCO2 dataset from Takahashi et al. (2009 (T09 using a recently developed software toolbox called FluxEngine to determine the importance of k and ΔpCO2 on CO2 budgets in two regions of the AO – the Greenland Sea (GS and the Barents Sea (BS with their continental margins. Results from the study indicate that the variability in wind speed and, hence, the gas transfer velocity, generally play a major role in determining the temporal variability of CO2 uptake, while variability in monthly ΔpCO2 plays a major role spatially, with some exceptions.

  1. 3D Numerical Study of Velocity Profiles and Thermal Mixing in Passive, Infrared Suppression Devices for Gas Turbine Engine Driven Generators

    National Research Council Canada - National Science Library

    Blackwell, Neal E

    2002-01-01

    ...) suppression device for exhaust ducting. The results, for a gas turbine driven generator, yield a novel design that is more compact and allows for shorter duct lengths, hence enabling associated camouflage netting to be lower in height...

  2. Modelado físico de la incidencia de un chorro de aire sobre una superficie de agua

    Directory of Open Access Journals (Sweden)

    Zenit, R.

    2010-10-01

    Full Text Available The use of gas jets (oxygen plays a key role in several steelmaking processes as in the Basic Oxygen Furnace (BOF or in the Electric Arc Furnace (EAF. Those jets improve heat, mass and momentum transfer in the liquid metal, mixing of chemical species enhancing and govern the formation of foaming slag. In this work experimental measurements were performed to determine the dimensions of the cavity formed at the liquid free surface caused by a gas jet impinging on it; also velocities vectors were measured in the zone affected by the gas jet. Cavities were measured from images from high speed camera and the vector maps were obtained with a Particle Image Velocimetry (PIV technique. Both velocities and cavities were determined as a function of the main process variables: gas flow rate, distance of the nozzle from the free surface and lance angle. Cavity dimensions were statistically processed treated as a function of the process variables and also as a function of the proper dimensionless numbers that govern these phenomena. It was found thatWeber and Froude numbers govern the cavity geometry. Liquid flow driven by the jet is mainly affected by the air flow rate, lance height and angle.El uso de chorros de gas (oxígeno es fundamental en diversos procesos de aceración, como el Horno Básico de Oxígeno (BOF, por sus siglas en inglés o en el Horno Eléctrico de Arco (EAF. Estos chorros mejoran la transferencia de calor, masa y cantidad de movimiento en el metal y el mezclado de especies y son muy importantes en la formación de escoria espumosa. En este trabajo, se realizaron mediciones experimentales de las dimensiones de la cavidad formada en la superficie líquida por la incidencia de un chorro, así como también se obtuvieron vectores de velocidad en la zona aledaña a dicha cavidad. Éstas, se midieron usando una cámara de alta velocidad, mientras que los mapas vectoriales se obtuvieron por la técnica PIV (Particle Image Velocimetry. Las

  3. Superficial tension: experimental model with simple materials

    Directory of Open Access Journals (Sweden)

    Tintori Ferreira, María Alejandra

    2012-09-01

    Full Text Available In this work appears a didactic offer based on an experimental activity using materials of very low cost, orientated to achieving that the student understand and interpret the phenomenon of superficial tension together with the importance of the modeling in sciences. It has as principal aim of education bring the student over to the mechanics of the static fluids and the intermolecular forces, combining scientific contents with questions near to the student what provides an additional motivation to the reflection of the scientific investigation.

  4. Superficial Vein Thrombophlebitis in a Football Athlete.

    Science.gov (United States)

    Schleich, Kevin T; Smoot, M Kyle

    2016-03-01

    A 22-year-old professional football player presented to a preparticipation physical examination with a 2-week history of left leg discomfort extending from the groin to the knee over the previous 2 weeks. He was found to have superficial vein thrombophlebitis (SVT) of the left great saphenous vein extending from the knee to within approximately 1.6 cm of the saphenofemoral junction. There is paucity in the literature regarding the management of SVT, particularly in actively training athletes. This case addresses the considerations of anticoagulation management for SVT as well as the unique challenge of managing anticoagulation therapy in an athlete that is actively training.

  5. Temperature distributions in 136 superficial radiothermotherapies

    International Nuclear Information System (INIS)

    Willich, N.; Duve, S.; Pfluger, T.; Bachmeier, K.

    1992-01-01

    Temperature distributions from 136 superficial radiothermotherapies in patients were analysed and three-dimensionally reconstructed. The calculation of mean values and standard deviations of the temperature measuring probes considering water bolus temperature, master probe temperature, site of the probes relatively to different applicator positions and site of the probes in the heated tissues yielded satisfactory temperature distributions for chest wall treatment in contrast to other regions of the body. Radiothermotherapy was statistically not superior to radiotherapy alone with respect to local tumor control. (authors)

  6. Superficial femoral artery: current treatment options

    International Nuclear Information System (INIS)

    Tepe, Gunnar; Schmehl, Joerg; Heller, Stephan; Wiesinger, Benjamin; Claussen, Claus D.; Duda, Stephan H.

    2006-01-01

    Treatment of the superficial femoral artery (SFA) has been among the least effective of all endovascular procedures in terms of long-term patency. The relatively small vessel lumen, in conjunction with a high plaque burden, slow flow, and a high frequency of primary occlusions, contributes to a considerable rate of acute technical failures. Because of these technical limitations a much effort has been made during the past years. This manuscript should summarize the hopes and limitations of different approaches such as brachytherapy, cutting balloons, stents and stent grafts, drug-eluting stents, and drug-coated balloons. (orig.)

  7. The spatial filtering method for solid particle velocity measurement based on an electrostatic sensor

    International Nuclear Information System (INIS)

    Xu, Chuanlong; Tang, Guanghua; Zhou, Bin; Wang, Shimin

    2009-01-01

    The spatial filtering method for particle velocity measurement has the advantages of simplicity of the measurement system and convenience of data processing. In this paper, the relationship between solid particles mean velocity in a pneumatic pipeline and the power spectrum of the output signal of an electrostatic sensor was mathematically modeled. The effects of the length of the sensor, the thickness of the dielectric pipe and its length on the spatial filtering characteristics of the sensor were also investigated using the finite element method. As for the roughness of and the difficult determination of the peak frequency f max of the power spectrum characteristics of the output signal of the sensor, a wavelet analysis based filtering method was applied to smooth the curve, which can accurately determine the peak frequency f max . Finally, experiments were performed on a pilot dense phase pneumatic conveying rig at high pressure to test the performance of the velocity measurement system. The experimental results show that the system repeatability is within ±4% over a gas superficial velocity range of 8.63–18.62 m s −1 for a particle concentration range of 0.067–0.130 m 3 m −3

  8. Local liquid velocity measurement in trickle bed reactors (TBRs) using the x-ray digital industrial radiography (DIR) technique

    Science.gov (United States)

    Anuar Mohd Salleh, Khairul; Lee, Hyoung Koo; Al-Dahhan, Muthanna H.

    2014-01-01

    This work describes the development of a new technique to measure local liquid velocity (VLL) for multiphase flows in trickle bed reactors (TBRs) (gas-liquid-solid system). In the studied TBR, the liquid phase is represented by water, gas by air and 3 mm expanded polystyrene beads as the solid packing. Three different superficial liquid velocities (VSL) and a constant superficial gas velocity (VSG) were used in the packed bed with an internal diameter of 4.25 cm. While the liquid is moving into the packed bed, tracking particles of 106-125 μm diameter (16.45% difference) are injected. The movement of the tracking particles is monitored and digitally recorded by a complementary metal-oxide-semiconductor detector. In this experiment, x-rays were used as the radiation source. Four replications were made with fresh packing. Comparable observations can be found from other published techniques (i.e. magnetic resonance imaging). Results from this study indicate that, at VSL = 0.13 cm s-1, the measured VLL can reach up to 51 times that of its VSL, while for VSL = 0.27 cm s-1, the measured VLL reached up to 35 times higher than the VSL and for VSL = 0.39 cm s-1, the VLL reached up to 39.8 times higher than its VSL. Through statistical analysis, the implementation of such a method is found to be reproducible throughout the experiments. The mean per cent difference in the measured VLL was 10% and 5% for lower implemented VSL of 0.13 and 0.27 cm s-1, respectively. At higher VSL (0.39 cm s-1), the particle tracer was greatly distributed and carried away by the high liquid flow rate. The variance or the range of the measured VLL does not vary for all replications in every VSL, which confirms the reproducibility of the experimental measurements, regardless of the VSL.

  9. Axial dispersion, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column by radiotracer residence time distribution analysis.

    Science.gov (United States)

    Din, Ghiyas Ud; Chughtai, Imran Rafiq; Inayat, Mansoor Hameed; Khan, Iqbal Hussain

    2008-12-01

    Axial dispersion, holdup and slip velocity of dispersed phase have been investigated for a range of dispersed and continuous phase superficial velocities in a pulsed sieve plate extraction column using radiotracer residence time distribution (RTD) analysis. Axial dispersion model (ADM) was used to simulate the hydrodynamics of the system. It has been observed that increase in dispersed phase superficial velocity results in a decrease in its axial dispersion and increase in its slip velocity while its holdup increases till a maximum asymptotic value is achieved. An increase in superficial velocity of continuous phase increases the axial dispersion and holdup of dispersed phase until a maximum value is obtained, while slip velocity of dispersed phase is found to decrease in the beginning and then it increases with increase in superficial velocity of continuous phase.

  10. Superficial basal cell carcinoma: A comparison of superficial only subtype with superficial combined with other subtypes by age, sex and anatomic site in 3150 cases.

    Science.gov (United States)

    Pyne, John H; Myint, Esther; Barr, Elizabeth M; Clark, Simon P; David, Michael; Na, Renua; Hou, Ruihang

    2017-08-01

    Basal cell carcinoma (BCC) may present as superficial subtype alone (sBCC) or superficial combined with other subtypes. The objective of this study was to compare sBCC without or with other BCC subtypes by age, sex and anatomic site. We retrospectively collected superficial BCC with the above characteristics from an Australian center during 2009 to 2014. We recorded 1528 sBCC and 1622 superficial BCC combined with other BCC subtype cases. Males numbered 2007 and females 1140. On males, head sites (forehead, cheek, nose and ear combined) compared to limb plus trunk sites displayed a higher incidence of superficial BCC combined with either nodular and or aggressive BCC subtypes (OR 13.15 CI 95% 8.9-19.5 P < .0001). On females a similar comparison also found a higher incidence of superficial BCC combined with solid subtype BCC on head sites compared to trunk and limb sites (OR 9.66 CI 95% 5.8-16.1 P < .0001). Superficial BCC alone is more likely on younger females on trunk and limb sites. Small partial biopsies reported as sBCC may miss other BCC subtypes present with higher risk on facial sites for males and females. Males had smaller proportions of superficial only subtype BCC on facial and ear sites compared to females. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Drift velocity studies at a time projection chamber for various water contents in the gas mixture; Driftgeschwindigkeitsstudien an einer Zeit-Projektions-Kammer (TPC) bei unterschiedlichen Wassergehalten des Kammergases

    Energy Technology Data Exchange (ETDEWEB)

    Stoever, F.W.

    2007-03-15

    For the answer of different open questions in high energy physics the construction of a linear e{sup +}e{sup -} collider with a c. m. energy of up to one TeV is prepared. With this is connected a comprehensive development on detectors, which must satisfy the requirements of the planned experiments. For the track chamber a TPC is considered. Hereby it deals with a gas-based concept, which has already been proved in past experiments and which is at time further developed by means of test chambers. The composition of the gas mixtureplays hereby an important role. Impurities of the gas mixture, especially by oxygen and water from the ambient air are a fact, which occurs every time in the development phase and can scarcely be avoided. From this arose the motivation to study directly the effects of this impurities. The object of the present thesis are correlations between drift velocity and water content in the chamber gas of a TPC.

  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. Gas holdup in a reciprocating plate bioreactor: Non-Newtonian - liquid phase

    Directory of Open Access Journals (Sweden)

    Naseva Olivera S.

    2002-01-01

    Full Text Available The gas holdup was studied in non-newtonian liquids in a gas-liquid and gas-liquid-solid reciprocating plate bioreactor. Aqueous solutions of carboxy methyl cellulose (CMC; Lucel, Lučane, Yugoslavia of different degrees of polymerization (PP 200 and PP 1000 and concentration (0,5 and 1%, polypropylene spheres (diameter 8.3 mm; fraction of spheres: 3.8 and 6.6% by volume and air were used as the liquid, solid and gas phase. The gas holdup was found to be dependent on the vibration rate, the superficial gas velocity, volume fraction of solid particles and Theological properties of the liquid ohase. Both in the gas-liquid and gas-liquid-solid systems studied, the gas holdup increased with increasing vibration rate and gas flow rate. The gas holdup was higher in three-phase systems than in two-phase ones under otter operating conditions being the same. Generally the gas holdup increased with increasing the volume fraction of solid particles, due to the dispersion action of the solid particles, and decreased with increasing non-Newtonian behaviour (decreasing flow index i.e. with increasing degree of polymerization and solution concentration of CMC applied, as a result of gas bubble coalescence.

  15. Liquid-liquid mixing by gas injection in a pool configuration

    International Nuclear Information System (INIS)

    Corradini, M.L.

    1994-02-01

    An experimental apparatus was designed and constructed to study the mixing process of two immiscible liquids, in a pool configuration, by bottom gas injection. The apparatus consisted of a vertical pyrex conduit of 15.2 centimeters of internal diameter. To the lower part of the conduit was attached a porous plate through which the gas was injected. The experiments were photographically recorded. The pictures were digitized and a method was developed to quantify the mixing region thickness. This method requires knowledge of the void fraction, for each liquid, as a function of the superficial gas velocity. Because of this, void fraction was measured for the bubbly and churn flow regimes, in a pool configuration for every liquid. A new correlation, based on the drift flux model, is proposed for void fraction as a function of superficial gas velocity. It has been observed that mixing can start either in bubbly or churn flow regimes, depending on the liquid pair properties. Three mechanistic models were derived to aid in correlating the data, two for bubbly flow and one for churn flow. A transition region between these two flow regimes, was deduced, but not directly measured. A set of correlations was developed from the models and it is proposed to be implemented in current codes that model Molten Core Concrete Interactions (MCCI). The implications that the present work has on MCCI have been described. It can be deduced that mixing between the oxidic and the metallic phases will occur during the interaction

  16. The nature of the high-velocity gas in NGC 1275: first results with TAURUS-2 on the William Herschel telescope

    International Nuclear Information System (INIS)

    Unger, S.W.; Taylor, K.; Pedlar, A.; Ghataure, H.S.; Penston, M.V.; Robinson, A.

    1990-01-01

    Observations with a new imaging Fabry-Perot interferometer, TAURUS-2, show that there is a close spatial association between the two systems of emission-line gas in the active galaxy NGC 1275 (Perseus A, 3C84). It therefore seems likely that, as first suggested by previous authors, we are witnessing two galaxies in the process of colliding. We show that this hypothesis is consistent with all available observations of this object. (author)

  17. Social network extraction based on Web: 1. Related superficial methods

    Science.gov (United States)

    Khairuddin Matyuso Nasution, Mahyuddin

    2018-01-01

    Often the nature of something affects methods to resolve the related issues about it. Likewise, methods to extract social networks from the Web, but involve the structured data types differently. This paper reveals several methods of social network extraction from the same sources that is Web: the basic superficial method, the underlying superficial method, the description superficial method, and the related superficial methods. In complexity we derive the inequalities between methods and so are their computations. In this case, we find that different results from the same tools make the difference from the more complex to the simpler: Extraction of social network by involving co-occurrence is more complex than using occurrences.

  18. Antibody conjugate radioimmunotherapy of superficial bladder cancer

    International Nuclear Information System (INIS)

    Perkins, Alan; Hopper, Melanie; Murray, Andrea; Frier, Malcolm; Bishop, Mike

    2002-01-01

    The administration of antibody conjugates for cancer therapy is now proving to be of clinical value. We are currently undertaking a programme of clinical studies using the monoclonal antibody C 595 (gG3) which reacts with the MUC1 glycoprotein antigen that is aberrantly expressed in a high proportion of bladder tumours. Radio immuno conjugates of the C 595 antibody have been produced with high radiolabelling efficiency and immuno reactivity using Tc-99 m and In-111 for diagnostic imaging, and disease staging and the cytotoxic radionuclides Cu-67 and Re-188 for therapy of superficial bladder cancer. A Phase I/II therapeutic trail involving the intravesical administration of antibody directly into the bladder has now begun. (author)

  19. Superficial biopsy of the cervix: new technique

    Directory of Open Access Journals (Sweden)

    Ettore De Girolami

    2002-06-01

    Full Text Available Cytological examination of the cervix in all patients is considered a necessity. A new technique of superficial biopsy is described and advantages en. numeratedEl Autor presenta una nueva técnica para biopsia superficial, considerando la necesidad de hacer rutinariamente a todas las pacientes el examen citológico del cérvix. La muestra se toma con el extremo de un aplicador cubierto de gaza. Este dispositivo, humedecido previamente en una solución de etanol, metanol y éter etílico, se aplica inmediatamente al cérvix del útero y, dándole un movimiento como el de las manecillas del reloj, se toma la muestra con la que se hacen frotis por aposición que se colorean por el método de Giemsa. Esta técnica ofrece la ventaja de que el tejido en estudio se adhiere perfectamente a la gaza, la cual, con el movimiento de rotación, desprende las células del "os uteri", las que son fijadas al mismo tiempo. La preparación del dispositivo es sumamente sencilla. La prueba resulta de bajo costo como de breve y fácil realizaciónL' Autore prende in considerazione l'utilitá dell' esame citologico del collo dell'utero, fatto rutinariamente a tutte le pazienti. Si descrive una nuova tecnica di biopsia superficiale che oltfe ad offrire dei vantaggi é di poca spesa e si puó eseguire con facilitá ed in breve tempo

  20. Experimental investigation on flow patterns of gas-liquid two-phase upward flow through packed channel with spheres

    International Nuclear Information System (INIS)

    Zhang Nan; Sun Zhongning; Zhao Zhongnan

    2011-01-01

    Experiments of visualized two-phase upward flow were conducted in the packed channel, which filled with 3, 5, 8 mm in diameter of glass sphere respectively. The gas superficial velocity ranges from 0.005 to 1.172 m/s. The liquid superficial velocity ranges from 0.004 to 0.093 m/s. Four representative flow patterns were observed as bubbly flow, cluster flow, liquid-pulse flow and churn-pulse flow, and corresponding flow pattern maps were also presented. It is found that the pulse flow region is dominant. The comparisons of flow pattern map between packed channel and non-packed channel show that the bubbly flow region in packed channel is narrower than that of non-packed channel due to the packing. The comparisons of flow pattern maps for three different packing sizes show that the cluster flow region expands with the increase of the packing diameter. In the low liquid superficial velocity, the cluster flow directly changes to churn-pulse flow in the packed channel with 8 mm packing. (authors)

  1. Sound Velocity in Soap Foams

    International Nuclear Information System (INIS)

    Wu Gong-Tao; Lü Yong-Jun; Liu Peng-Fei; Li Yi-Ning; Shi Qing-Fan

    2012-01-01

    The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration

  2. Volumetric and superficial characterization of carbon activated; Caracterizacion volumetrica y superficial de carbon activado

    Energy Technology Data Exchange (ETDEWEB)

    Carrera G, L.M.; Garcia S, I.; Jimenez B, J.; Solache R, M.; Lopez M, B.; Bulbulian G, S.; Olguin G, M.T. [Departamento de Quimica, Gerencia de Ciencias Basicas, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The activated carbon is the resultant material of the calcination process of natural carbonated materials as coconut shells or olive little bones. It is an excellent adsorbent of diluted substances, so much in colloidal form, as in particles form. Those substances are attracted and retained by the carbon surface. In this work is make the volumetric and superficial characterization of activated carbon treated thermically (300 Centigrade) in function of the grain size average. (Author)

  3. Cuantificación de la contaminación del gas de protección en procesos de soldadura con arco eléctrico por medio de mediciones de oxígeno en la superficie del material base Quantification of contamination of the shielding gas in arc welding processes through measurement of oxygen on the surface of the base material

    Directory of Open Access Journals (Sweden)

    Julio Fuentes-Muñoz

    2012-09-01

    Full Text Available A metodologia apresentada neste trabalho se baseia em medições do teor de oxigênio na superfície do metal base, possibilitando assim, uma avaliação quantitativa da contaminação do gás de proteção. Os gases utilizados nos processos de soldagem definem as características do arco e protegem a poça de soldagem. A contaminação do gás, por exemplo, com o ar do meio ambiente, prejudica as propriedades da união soldada. A contaminação do gás de proteção não é somente dependente da qualidade do gás utilizado, como também tem que ser considerado os componentes contidos na tocha. Até agora, o nível da contaminação do gás produzido pela tocha tem sido analisado somente de forma empírica, avaliando a qualidade e forma do cordão de solda. A medição do oxigênio na superfície do metal de base é um método simples e preciso para analisar o nível de contaminação do gás de proteção. Este procedimento permite uma avaliação quantitativa, inclusive na presença do arco. No contexto deste trabalho se apresentará por meio de exemplos em tochas TIG e MIG/MAG as possibilidades da utilização desta metodologia para o desenvolvimento e análise de processos de soldagem a arco.The method presented in this paper is based on the measurement of oxygen on the surface of the base metal to enable a quantitative assessment of the contamination in the shielding gas. The gas used in arc processes affected arc properties and simultaneously protected the welding pool. The contamination of the shielding gases, e.g. with atmospheric air, damages the properties of the weld joint. The contamination in the shielding gas is not only dependent on the purity of the utilized gas, but also on the components of the welding torch. The level of contamination in the gas produced by the torch had been analyzed so far only by empirical evaluation of the quality and appearance of the welding seam. The measurement of oxygen on the surface of the base

  4. CFD simulation of gas-liquid floating particles mixing in an agitated vessel

    Directory of Open Access Journals (Sweden)

    Li Liangchao

    2017-01-01

    Full Text Available Gas dispersion and floating particles suspension in an agitated vessel were studied numerically by using computational fluid dynamics (CFD. The Eulerian multi-fluid model along with standard k-ε turbulence model was used in the simulation. A multiple reference frame (MRF approach was used to solve the impeller rotation. The velocity field, gas and floating particles holdup distributions in the vessel were first obtained, and then, the effects of operating conditions on gas dispersion and solid suspension were investigated. The simulation results show that velocity field of solid phase and gas phase are quite different in the agitated vessel. Floating particles are easy to accumulate in the center of the surface region and the increasing of superficial gas velocity is in favor of floating particles off-surface suspension. With increasing solids loading, the gas dispersion becomes worse, while relative solid holdup distribution changes little. The limitations of the present modeling are discussed and further research in the future is proposed.

  5. Size exclusion chromatography with superficially porous particles.

    Science.gov (United States)

    Schure, Mark R; Moran, Robert E

    2017-01-13

    A comparison is made using size-exclusion chromatography (SEC) of synthetic polymers between fully porous particles (FPPs) and superficially porous particles (SPPs) with similar particle diameters, pore sizes and equal flow rates. Polystyrene molecular weight standards with a mobile phase of tetrahydrofuran are utilized for all measurements conducted with standard HPLC equipment. Although it is traditionally thought that larger pore volume is thermodynamically advantageous in SEC for better separations, SPPs have kinetic advantages and these will be shown to compensate for the loss in pore volume compared to FPPs. The comparison metrics include the elution range (smaller with SPPs), the plate count (larger for SPPs), the rate production of theoretical plates (larger for SPPs) and the specific resolution (larger with FPPs). Advantages to using SPPs for SEC are discussed such that similar separations can be conducted faster using SPPs. SEC using SPPs offers similar peak capacities to that using FPPs but with faster operation. This also suggests that SEC conducted in the second dimension of a two-dimensional liquid chromatograph may benefit with reduced run time and with equivalently reduced peak width making SPPs advantageous for sampling the first dimension by the second dimension separator. Additional advantages are discussed for biomolecules along with a discussion of optimization criteria for size-based separations. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Superficial siderosis: Case report and literature review

    Directory of Open Access Journals (Sweden)

    Kresojević Nikola D.

    2013-01-01

    Full Text Available Introduction. Superficial siderosis (SS is caused by chronic subarachnoid bleeding and is characterized by free iron and hemosiderin deposition along the pial and subpial structures of central nervous system. SS leads to progressive and irreversible CNS damage. The most common causes of chronic subarachnoidal bleeding are tumors, head and spinal cord trauma, arteriovenous malformations and aneurysms. SS is characterized by clinical triad: sensorineural hearing loss, cerebellar ataxia and piramydal signs. Brain MR imaging is the investigation of choice for the diagnosis of SS. Typical findings include hypointensities seen on T2­weighted MR imaging around the brain, cerebellum, brain stem, spinal cord, VIII cranial nerve and atrophy of cerebellum and medulla. Case Outline. A 71-year­old female patient noticed hand tremor in the middle of the third decade of life, and later slowly progressive bilateral hearing loss. At the age of 64 she developed un­ steady gate, hand clumsiness and dysarthria, to became incapable of independent walking and standing five years later. Clinical course and brain MRI findings were typical for SS, but additional investigation did not reveal the couse of subarahnoidal bleeding. Conclusion. SS represents a rare and under­recognized condition that must be considered in all patients with cerebellar syndrome of unknown cause. Early diagnosis of SS in some cases with identified cause of chronic bleeding allowes therapeutic interventions that may prevent further progression of the disease. [Projekat Ministarstva nauke Republike Srbije, br. 175090

  7. Modified Functional Superficial Parotidectomy With Ligation of the Major Branch of the Parotid Duct Extending to the Superficial Lobe.

    Science.gov (United States)

    Chang, Jung Woo; Leem, Soo Seong; Choi, Hwan Jun; Lee, Jang Hyun

    2017-05-01

    A functional superficial parotidectomy can maintain salivary function by preserving the Stensen duct. However, this technique still brings the possibility of salivary leakage, because major branches of the parotid duct from the resected site do not get ligated. To reduce this complication, this study introduces a modified technique with major branch ligation. From December 2008 to February 2015, 14 patients who underwent superficial parotidectomy were divided into 2 groups. Group A was treated with the modified functional superficial parotidectomy involving the major branch between the superficial lobe and parotid duct. Group B was treated with the conventional superficial parotidectomy without involving the major branch of the parotid duct. The clinical complications, period of Hemovac usage, and surgical duration were noted in each group. Two of 8 patients in group A had a major branch from Stensen duct that was ligated, and there was no evidence of salivary leakage or sialocele in any of the patients of group A, whereas group B contained 2 cases of salivary leakage, one of which became sialocele. Group A had a significantly longer Hemovac maintenance period than group B (P < 0.05), and the duration of surgery was also significantly different between the 2 groups (P < 0.05). Because a solitary major branch of the main parotid duct occasionally extends toward the superficial lobe, our modified technique-functional superficial parotidectomy with ligation of the major branch toward the superficial lobe-is a useful option for treatment of a benign parotid mass in such cases.

  8. Local liquid velocity measurement of Trickle Bed Reactor using Digital Industrial X-ray Radiography

    Science.gov (United States)

    Mohd Salleh, Khairul Anuar

    Trickle Bed Reactors (TBRs) are fixed beds of particles in which both liquid and gas flow concurrently downward. They are widely used to produce not only fuels but also lubrication products. The measurement and the knowledge of local liquid velocities (VLL) in TBRs is less which is essential for advancing the understanding of its hydrodynamics and for validation computational fluid dynamics (CFD). Therefore, this work focused on developing a new, non-invasive, statistically reliable technique that can be used to measure local liquid velocity (VLL) in two-dimensions (2-D). This is performed by combining Digital Industrial X-ray Radiography (DIR) and Particle Tracking Velocimetry (PTV) techniques. This work also make possible the development of three-dimensional (3-D) VLL measurements that can be taken in TBRs. Measurements taken through both the combined and the novel technique, once validated, were found to be comparable to another technique (a two-point fiber optical probe) currently being developed at Missouri University of Science and Technology. The results from this study indicate that, for a gas-liquid-solid type bed, the measured VLL can have a maximum range that is between 35 and 51 times that of its superficial liquid velocity (VSL). Without the existence of gas, the measured VLL can have a maximum range that is between 4 and 4.7 times that of its VSL. At a higher V SL, the particle tracer was greatly distributed and became carried away by a high liquid flow rate. Neither the variance nor the range of measured VLL varied for any of the replications, confirming the reproducibility of the experimental measurements used, regardless of the VSL . The liquid's movement inside the pore was consistent with findings from previous studies that used various techniques.

  9. Hemipelvic irradiation for superficial bladder cancer

    International Nuclear Information System (INIS)

    Tashiro, Kazuya; Machida, Toyohei; Ooishi, Yukihiko; Ueda, Masataka; Kido, Akira; Wada, Tetsuro; Yoshigoe, Fukuo; Yamashita, Takashi; Mochizuki, Sachio

    1985-01-01

    In 15 patients with superficial bladder cancer hemipelvic irradiation was performed for prevention of relapse of cancer and decrease in side effects with following results. All patients received TUR-Bt at our department during the six years period from 1978 to 1983. As to stages, one was classified as Ta, 11 as T 1 and 3 as T 2, and pathologic diagnosis was transitional epithelial carcinoma of grade 1 in 1 case, grade 2 in 8 cases and grade 3 in 6 cases. Irradiation was started from the 7 th to 14 th day after TUR-Bt. At first, hemipelvic anterior and posterior field including the field from the affected pelvis to 1 to 2 cm beyond the midline toward the contralateral side and from the aortic bifurcation to the prostatic urethra were irradiated at a dose of 45 Gy. Then, whole bladder field was given an additional rotation irradiation of 20 Gy. The mean observation period was 43 months (ranging from 12 to 79 months) and relapse of cancer was observed in 6 cases out of 15 cases (40%). The site of relapse was in the irradiated site in 2 cases, contralateral site in 3 cases and both side in 1 cases. However, in all of the relapsed cases no aggravation in differential degree or progression in stage was observed. As the side effects, radiation cystitis developed as a delayed damage in 1 case. Thus, although no efficacy for prevention of relapse which we had expected was not seen, this irradiation method effectively inhibited the progression of lesion and development of delayed damage. (author)

  10. Hemipelvic irradiation for superficial bladder cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tashiro, Kazuya; Machida, Toyohei; Ooishi, Yukihiko; Ueda, Masataka; Kido, Akira; Wada, Tetsuro; Yoshigoe, Fukuo; Yamashita, Takashi; Mochizuki, Sachio

    1985-02-01

    In 15 patients with superficial bladder cancer hemipelvic irradiation was performed for prevention of relapse of cancer and decrease in side effects with following results. All patients received TUR-Bt at our department during the six years period from 1978 to 1983. As to stages, one was classified as Ta, 11 as T 1 and 3 as T 2, and pathologic diagnosis was transitional epithelial carcinoma of grade 1 in 1 case, grade 2 in 8 cases and grade 3 in 6 cases. Irradiation was started from the 7 th to 14 th day after TUR-Bt. At first, hemipelvic anterior and posterior field including the field from the affected pelvis to 1 to 2 cm beyond the midline toward the contralateral side and from the aortic bifurcation to the prostatic urethra were irradiated at a dose of 45 Gy. Then, whole bladder field was given an additional rotation irradiation of 20 Gy. The mean observation period was 43 months (ranging from 12 to 79 months) and relapse of cancer was observed in 6 cases out of 15 cases (40%). The site of relapse was in the irradiated site in 2 cases, contralateral site in 3 cases and both side in 1 cases. However, in all of the relapsed cases no aggravation in differential degree or progression in stage was observed. As the side effects, radiation cystitis developed as a delayed damage in 1 case. Thus, although no efficacy for prevention of relapse which we had expected was not seen, this irradiation method effectively inhibited the progression of lesion and development of delayed damage. (author).

  11. Enhancement of oxygen mass transfer and gas holdup using palm oil in stirred tank bioreactors with xanthan solutions as simulated viscous fermentation broths.

    Science.gov (United States)

    Mohd Sauid, Suhaila; Krishnan, Jagannathan; Huey Ling, Tan; Veluri, Murthy V P S

    2013-01-01

    Volumetric mass transfer coefficient (kLa) is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kLa. The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and kLa on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v) of palm oil raised the kLa of xanthan solution by 1.5 to 3 folds with the highest kLa value of 84.44 h(-1). It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The kLa values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients.

  12. Enhancement of Oxygen Mass Transfer and Gas Holdup Using Palm Oil in Stirred Tank Bioreactors with Xanthan Solutions as Simulated Viscous Fermentation Broths

    Directory of Open Access Journals (Sweden)

    Suhaila Mohd Sauid

    2013-01-01

    Full Text Available Volumetric mass transfer coefficient (kLa is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kLa. The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and kLa on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v of palm oil raised the kLa of xanthan solution by 1.5 to 3 folds with the highest kLa value of 84.44 h−1. It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The kLa values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients.

  13. Trauma ocupacional por corpo estranho corneano superficial Occupational trauma due to superficial corneal foreign body

    Directory of Open Access Journals (Sweden)

    Vanessa Miroski Gerente

    2008-04-01

    Full Text Available OBJETIVO: Avaliar a epidemiologia do trauma ocular por corpo estranho superficial de córnea. MÉTODOS: Os pacientes atendidos no Pronto-Socorro da Universidade Federal de São Paulo entre abril e junho de 2005 que apresentaram corpo estranho superficial de córnea foram entrevistados. Foram avaliados: sexo, idade, profissão, registro legal do emprego, uso, disponibilidade e tipo de equipamentos de proteção utilizados e a fiscalização do seu uso. O conhecimento das complicações deste tipo de acidente também foi avaliado. Os resultados foram analisados com teste do qui quadrado ou teste de Fisher. RESULTADOS: Foram entrevistados 123 pacientes. Apenas 3 eram do sexo feminino e a idade média foi de 36 anos. A maioria destes traumas ocorreu no ambiente de trabalho (86,2% e 58,4% não possuíam registro legal do emprego. As profissões mais freqüentemente envolvidas foram serralheiro, pedreiro e metalúrgico. Em 79,8% dos locais de trabalho havia equipamentos de proteção e 85,3% dos pacientes eram orientados a usá-los. Em 52,4% dos locais sua utilização era fiscalizada, mas apenas 34,2% usavam no momento do trauma. A utilização foi mais freqüente (p=0,008 e fiscalização mais presente (p=0,0415 entre pacientes com registro legal de emprego. Questionados sobre os riscos, 68,9% dos pacientes tinham consciência das complicações graves deste tipo de acidente. CONCLUSÃO: A maioria dos pacientes tem conhecimento sobre a gravidade do trauma ocular e este tipo de lesão ocorre mesmo em locais com equipamentos de proteção disponíveis, alguns deles até durante o seu uso. Os dados sugerem que enfoque maior da prevenção deve ser na fiscalização e utilização de equipamentos adequados.PURPOSE: To evaluate the epidemiology of superficial corneal foreign body. METHODS: Patients who were seen at the Emergency Service of the Federal University of São Paulo, from April/05 to June/05, were screened and those with superficial corneal

  14. Superficial herpes simplex virus wound infection following lung transplantation.

    Science.gov (United States)

    Karolak, Wojtek; Wojarski, Jacek; Zegleń, Sławomir; Ochman, Marek; Urlik, Maciej; Hudzik, Bartosz; Wozniak-Grygiel, Elzbieta; Maruszewski, Marcin

    2017-08-01

    Surgical site infections (SSIs) are infections of tissues, organs, or spaces exposed by surgeons during performance of an invasive procedure. SSIs are classified into superficial, which are limited to skin and subcutaneous tissues, and deep. The incidence of deep SSIs in lung transplant (LTx) patients is estimated at 5%. No reports have been published as to the incidence of superficial SSIs specifically in LTx patients. Common sense would dictate that the majority of superficial SSIs would be bacterial. Uncommonly, fungal SSIs may occur, and we believe that no reports exist as to the incidence of viral wound infections in LTx patients, or in any solid organ transplant patients. We report a de novo superficial wound infection with herpes simplex virus following lung transplantation, its possible source, treatment, and resolution. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Imaging of the most frequent superficial soft-tissue sarcomas

    International Nuclear Information System (INIS)

    Morel, Melanie; Taieb, Sophie; Ceugnart, Luc; Penel, Nicolas; Mortier, Laurent; Vanseymortier, Luc; Robin, Y.M.; Gosset, Pierre; Cotten, Anne

    2011-01-01

    Superficial soft-tissue sarcomas are malignant mesenchymal tumors located within the cutaneous and/or subcutaneous layers. Most superficial soft-tissue sarcomas are low-grade tumors; yet, the risk of local recurrence is high, and initial wide surgery is the main prognostic factor. Some of these superficial sarcomas may grow, following an infiltrative pattern, and their real extent may be underestimated clinically. Imaging techniques are useful to determine precisely the real margins of the tumor, especially in cases of clinically doubtful or recurrent or large superficial lesions. Imaging tools enable one to determine the relationship with the superficial fascia separating the subcutaneous layer from the underlying muscle. In our institution ultrasonographic examination is followed by magnetic resonance (MR) imaging when the size of the lesion exceeds 3-5 cm. Imaging assessment is performed prior to biopsy, enabling optimal surgical management. Imaging features of the main superficial sarcomas are detailed in the following article, according to their major locations: those arising in the epidermis and/or dermis, which are most often diagnosed by dermatologists, and the subcutaneous sarcomas. (orig.)

  16. Imaging of the most frequent superficial soft-tissue sarcomas

    Energy Technology Data Exchange (ETDEWEB)

    Morel, Melanie; Taieb, Sophie; Ceugnart, Luc [Centre Oscar Lambret, Department of Radiology, Lille (France); Penel, Nicolas [Centre Oscar Lambret, Department of Oncology, Lille (France); Mortier, Laurent [Centre Hospitalier Universitaire de Lille, Department of Dermatology, Hopital Claude Huriez, Lille (France); Vanseymortier, Luc [Centre Oscar Lambret, Department of Surgery, Lille (France); Robin, Y.M. [Centre Oscar Lambret, Departement of Pathology, Lille (France); Gosset, Pierre [Groupement Hospitalier de l' Institut Catholique-Faculte Libre de Medecine de Lille, Department of Pathology, Hopital Saint-Philibert, Lomme (France); Cotten, Anne [Centre Hospitalier Universitaire de Lille, Department of Musculoskeletal Radiology, Centre Hopital Roger Salengro, Lille (France)

    2011-03-15

    Superficial soft-tissue sarcomas are malignant mesenchymal tumors located within the cutaneous and/or subcutaneous layers. Most superficial soft-tissue sarcomas are low-grade tumors; yet, the risk of local recurrence is high, and initial wide surgery is the main prognostic factor. Some of these superficial sarcomas may grow, following an infiltrative pattern, and their real extent may be underestimated clinically. Imaging techniques are useful to determine precisely the real margins of the tumor, especially in cases of clinically doubtful or recurrent or large superficial lesions. Imaging tools enable one to determine the relationship with the superficial fascia separating the subcutaneous layer from the underlying muscle. In our institution ultrasonographic examination is followed by magnetic resonance (MR) imaging when the size of the lesion exceeds 3-5 cm. Imaging assessment is performed prior to biopsy, enabling optimal surgical management. Imaging features of the main superficial sarcomas are detailed in the following article, according to their major locations: those arising in the epidermis and/or dermis, which are most often diagnosed by dermatologists, and the subcutaneous sarcomas. (orig.)

  17. Drenaje suplementario del sistema venoso superficial en colgajos pediculados Supplementary drainage of superficial venous system in pedicled flaps

    Directory of Open Access Journals (Sweden)

    A. Fernández García

    2012-06-01

    Full Text Available Los colgajos pediculados pueden sufrir edema y congestión debido a que su drenaje a trevés del sistema venoso superfical es imposible y el flujo hacia el sistema profundo a nivel del pedículo es precario. Esta situación suele evolucionar hacia la necrosis parcial o la pérdida total del colgajo en pocas horas. La apertura del sistema venoso superficial permite el drenaje adecuado de los tejidos transferidos y evita estas complicaciones. Este artículo analiza el papel de las anastomosis microquirúrgicas en el sistema venoso superficial de los colgajos pediculados. Esta técnica permite comunicar el sistema venoso superfical de los tejidos transferidos con el sistema venoso superficial del territorio que rodea al defecto. Presentamos los resultados obtenidos con esta técnica en colgajos de perforante en hélice, colgajos miocutáneos, colgajos neurocutáneos y colgajos fasciograsos volteados.The pedicled flaps can suffer edema and congestion due to the impossibility of drainage toward the superficial venous system and the precarious flow via the deep system at the level of the pedicle. The evolution of this situation is usually partial necrosis or total loss of the flap in a few hours. The opening of the venous superficial system achieves an appropriate drainage of the transfered tissues and avoids these complications. In this article we analyze the role of the microsurgical anastomosis at the level of the superficial venous system of pedicled flaps. This technique allows to communicate the superficial venous system of the transfered tissues with the superficial venous system of the territory around the defect. We report the results with this method in propeller perforator flaps, miocutaneous flaps, neurocutaneous flaps and adipofascial turn over flaps.

  18. Neuralfussy multivariable control applied to the control of velocity, power, and exhaust gas temperature of a turbo gas unit; Control neurodifuso multivariable aplicado al control de velocidad, potencia y temperatura de gases de escape de una unidad turbogas

    Energy Technology Data Exchange (ETDEWEB)

    Segura Ozuna, Victor Octavio

    2004-11-15

    The electric power demand in Mexico has forced to the electric sector to be in a constant search of methods and systems that, among other objectives, improve the operation of the generating power stations of electric power continually. As part of their mission, the Electrical Research Institute (IIE) has promoted and leaning the applied research and the technological development to improve the indexes of security, readiness, dependability, efficiency and durability of central generating by means of the development and the installation of big digital systems of information and control. At the present time, inside the scheme of electric power generation, the gas turbine (UTG) represent 7% of the generation of the national electric sector [1]. These units have become the dominant way of the new electric generation in the U.S, either in simple cycle or combined. The above-mentioned, is attributable at less installation cost for generated kilowatt, to the shortest construction programs, at first floor levels of emission of pollutants and competitive operation costs. The control system of the gas turbine is based on conventional control algorithms of the type PI [2]. This control scheme is dedicated for regulation tasks and rejection to interferences, and it doesn't stop pursuit of reference points. The controllers act all on a control valve, that which represents a strong interaction among the same ones, for example an adjustment in the parameters of the algorithm of the digital PI of temperature, it can improve their acting but it can also affect the acting of the speed control or that of power. The gas turbine presents a non lineal behavior and variant in the time, mainly in the starting stage where several important disturbances are presented. At the moment, the controllers used in the scheme of control of the turbines are lineal, which are syntonized for a specific operation point and they are conserved this way by indefinite time. In this thesis the

  19. Interfacial area, velocity and void fraction in two-phase slug flow

    International Nuclear Information System (INIS)

    Kojasoy, G.; Riznic, J.R.

    1997-01-01

    The internal flow structure of air-water plug/slug flow in a 50.3 mm dia transparent pipeline has been experimentally investigated by using a four-sensor resistivity probe. Liquid and gas volumetric superficial velocities ranged from 0.55 to 2.20 m/s and 0.27 to 2.20 m/s, respectively, and area-averaged void fractions ranged from about 10 to 70%. The local distributions of void fractions, interfacial area concentration and interface velocity were measured. Contributions from small spherical bubbles and large elongated slug bubbles toward the total void fraction and interfacial area concentration were differentiated. It was observed that the small bubble void contribution to the overall void fraction was small indicating that the large slug bubble void fraction was a dominant factor in determining the total void fraction. However, the small bubble interfacial area contribution was significant in the lower and upper portions of the pipe cross sections

  20. Thermal particle image velocity estimation of fire plume flow

    Science.gov (United States)

    Xiangyang Zhou; Lulu Sun; Shankar Mahalingam; David R. Weise

    2003-01-01

    For the purpose of studying wildfire spread in living vegetation such as chaparral in California, a thermal particle image velocity (TPIV) algorithm for nonintrusively measuring flame gas velocities through thermal infrared (IR) imagery was developed. By tracing thermal particles in successive digital IR images, the TPIV algorithm can estimate the velocity field in a...

  1. Superficial dose evaluation of four dose calculation algorithms

    Science.gov (United States)

    Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei

    2017-08-01

    Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank

  2. Nerve conduction velocity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003927.htm Nerve conduction velocity To use the sharing features on this page, please enable JavaScript. Nerve conduction velocity (NCV) is a test to see ...

  3. Tendon vibration attenuates superficial venous vessel response of the resting limb during static arm exercise

    Directory of Open Access Journals (Sweden)

    Ooue Anna

    2012-11-01

    Full Text Available Abstract Background The superficial vein of the resting limb constricts sympathetically during exercise. Central command is the one of the neural mechanisms that controls the cardiovascular response to exercise. However, it is not clear whether central command contributes to venous vessel response during exercise. Tendon vibration during static elbow flexion causes primary muscle spindle afferents, such that a lower central command is required to achieve a given force without altering muscle force. The purpose of this study was therefore to investigate whether a reduction in central command during static exercise with tendon vibration influences the superficial venous vessel response in the resting limb. Methods Eleven subjects performed static elbow flexion at 35% of maximal voluntary contraction with (EX + VIB and without (EX vibration of the biceps brachii tendon. The heart rate, mean arterial pressure, and rating of perceived exertion (RPE in overall and exercising muscle were measured. The cross-sectional area (CSAvein and blood velocity of the basilic vein in the resting upper arm were assessed by ultrasound, and blood flow (BFvein was calculated using both variables. Results Muscle tension during exercise was similar between EX and EX + VIB. However, RPEs at EX + VIB were lower than those at EX (P P vein in the resting limb at EX decreased during exercise from baseline (P vein at EX + VIB did not change during exercise. CSAvein during exercise at EX was smaller than that at EX + VIB (P vein did not change during the protocol under either condition. The decreases in circulatory response and RPEs during EX + VIB, despite identical muscle tension, showed that activation of central command was less during EX + VIB than during EX. Abolishment of the decrease in CSAvein during exercise at EX + VIB may thus have been caused by a lower level of central command at EX + VIB rather than EX. Conclusion Diminished central command induced by tendon

  4. The velocity of sound

    International Nuclear Information System (INIS)

    Beyer, R.T.

    1985-01-01

    The paper reviews the work carried out on the velocity of sound in liquid alkali metals. The experimental methods to determine the velocity measurements are described. Tables are presented of reported data on the velocity of sound in lithium, sodium, potassium, rubidium and caesium. A formula is given for alkali metals, in which the sound velocity is a function of shear viscosity, atomic mass and atomic volume. (U.K.)

  5. Transverse Oscillations for Phased Array Vector Velocity Imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes; Jensen, Jørgen Arendt

    2010-01-01

    of superficial blood vessels. To broaden the usability of the method, it should be expanded to a phased array geometry enabling vector velocity imaging of the heart. Therefore, the scan depth has to be increased to 10-15 cm. This paper presents suitable pulse echo fields (PEF). Two lines are beamformed...... (correlation coefficient, R: -0.76), and therefore predict estimator performance. CV is correlated with the standard deviation (R=0.74). The results demonstrate the potential for using a phased array for vector velocity imaging at larger depths, and potentially for imaging the heart....

  6. Long-term evolution of superficial optic disc drusen

    DEFF Research Database (Denmark)

    Larsen, Lasse Malmqvist; Lund-Andersen, Henrik; Hamann, Steffen

    2017-01-01

    with hereditary ODD were included. Results: Mean age at initial and follow-up examination was, respectively, 16.8 and 73.3 years. The median follow-up time was 56 years. A minimal or non-existing change in superficial ODD anatomy (size and number) was seen in 10 of 12 eyes. There was a tendency towards more......Purpose: Optic disc drusen (ODD) is hyaline deposits in the optic nerve head seen in 1-2% of the population. Long-term evolution of ODD anatomy and visual field defects in ODD patients is a key factor for learning more about pathophysiology and prognosis of the condition. With a median follow......-up period of 56 years, this is the first study that evaluates superficial optic disc anatomy and visual fields in patients with ODD over a life span. Methods: Observational case series investigating progression of superficial optic disc anatomy and visual fields in ODD patients. Eight patients...

  7. Pigmented basal cell carcinoma mimicking a superficial spreading melanoma

    Directory of Open Access Journals (Sweden)

    Paula Hasbún Acuña

    2016-12-01

    Full Text Available Resumen El carcinoma basocelular es el cáncer de piel más frecuente, especialmente en personas de edad avanzada. El carcinoma basocelular pigmentado es una variante poco común que se ha descrito en la literatura como una lesión nodular hiperpigmentada. En raras ocasiones puede presentarse en forma de una extensa placa pigmentada, la cual puede ser clínicamente indistinguible del melanoma maligno de extensión superficial y de la enfermedad de Bowen. La dermatoscopía tiene una alta sensibilidad en el diagnóstico del carcinoma basocelular, cuando se utilizan los criterios de Menzies, aunque el diagnóstico final es histopatológico. El objetivo del presente trabajo es reportar y analizar el caso de una paciente con un extenso carcinoma basocelular superficial pigmentado, que simula un melanoma maligno de extensión superficial.

  8. Superficial siderosis of the central nervous system - A case report

    International Nuclear Information System (INIS)

    Mannalini, S.

    1997-01-01

    There is little information on superficial siderosis of the central nervous system (CNS) in the literature, mainly due to the rarity of the disease, the difficulties in diagnosis (autopsy pre magnetic resonance imaging (MRI)) and the long latency of the symptoms. With the advent of MRI, for the first time we are able to make a positive in vivo diagnosis. But this comes at a time of less disease incidence, and little clinical awareness. MRI is able to make the diagnosis because of the strong paramagnetic effect of haemosiderin, the blood by-product that is deposited on the brain surface in superficial siderosis of the CNS. The ability of the brain to biosynthesize ferritin in response to prolonged contact with haemosiderin is thought to be the most important factor in the pathogenesis of superficial siderosis. (author)

  9. Experiments on the superficial irradiation of spherical vegetables and fruits

    International Nuclear Information System (INIS)

    Kalman, B.; Kiraly, Z.

    1974-01-01

    A revolving facility was made for the homogeneous superficial irradiation of spherical vegetables and fruits (apricot, peach, tomato, apple, etc.) with fast electrons. After the building of the technological apparatus described in detail, dosimetrical measurements were carried out by a Van de Graff generator of 2 MV and it was proved, that the superficial irradiation had a smaller effect on the quality of the fresh fruits, than of the stored ones. The developed apparatus can be altered according to the ripe-rate of the products. (K.A.)

  10. Aneurysm of the superficial femoral artery in an infant

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, M.; Komuro, H.; Matoba, K.; Kaneko, M. [Dept. of Paediatric Surgery, Inst. of Clinical Medicine, Univ. of Tsukuba, Ibaraki (Japan); Niitsu, M.; Itai, Y. [Dept. of Radiology, Inst. of Clinical Medicine, Univ. of Tsukuba, Ibaraki (Japan)

    2003-04-01

    An isolated arterial aneurysm in childhood is extremely rare. We report a 1-year-old girl with an aneurysm of the right superficial femoral artery, presenting as an asymptomatic mass of the thigh. The aneurysm involved the whole superficial femoral artery (9 cm in length), and surgical treatment would have required replacement of the affected artery. Conservative treatment was chosen, influenced by the patient's rapid growth at that time. Non-invasive, 3-D contrast-enhanced magnetic resonance angiography (MRA) was useful as an alternative to conventional angiography for detailed evaluation of the femoral arteries, including the aneurysm. (orig.)

  11. Formation rate of natural gas hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Mork, Marit

    2002-07-01

    The rate of methane hydrate and natural gas hydrate formation was measured in a 9.5 litre stirred tank reactor of standard design. The experiments were performed to better understand the performance and scale-up of a reactor for continuous production of natural gas hydrates. The hydrate formation rate was measured at steady-state conditions at pressures between 70 and 90 bar and temperatures between 7 and 15 deg C. Between 44 and 56 % of the gas continuously supplied to the reactor was converted to hydrate. The experimental results show that the rate of hydrate formation is strongly influenced by gas injection rate and pressure. The effect of stirring rate is less significant and subcooling has no observable effect on the formation rate. Hydrate crystal concentration and gas composition do not influence the hydrate formation rate. Observations of produced hydrate crystals indicate that the crystals are elongated, about 5 micron in diameter and 10 micron long. Analysis of the results shows that the rate of hydrate formation is dominated by gas-liquid mass transfer. A mass transfer model, the bubble-to-crystal model, was developed for the hydrate formation rate in a continuous stirred tank reactor, given in terms of concentration driving force and an overall mass transfer coefficient. The driving force is the difference between the gas concentration at the gas-liquid interface and at the hydrate crystal surface. These concentrations correspond to the solubility of gas in water at experimental temperature and pressure and the solubility of gas at hydrate equilibrium temperature and experimental pressure, respectively. The overall mass transfer coefficient is expressed in terms of superficial gas velocity and impeller power consumption, parameters commonly used in study of stirred tank reactors. Experiments and modeling show that the stirred tank reactor has a considerable potential for increased production capacity. However, at higher hydrate production rates the

  12. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys; Estudo dos mecanismos envolvidos no processo de endurecimento superficial a laser de ligas metalicas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edmara Marques Rodrigues da

    2001-07-01

    The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO{sub 2} laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the

  13. Neutron stars velocities and magnetic fields

    Science.gov (United States)

    Paret, Daryel Manreza; Martinez, A. Perez; Ayala, Alejandro.; Piccinelli, G.; Sanchez, A.

    2018-01-01

    We study a model that explain neutron stars velocities due to the anisotropic emission of neutrinos. Strong magnetic fields present in neutron stars are the source of the anisotropy in the system. To compute the velocity of the neutron star we model its core as composed by strange quark matter and analice the properties of a magnetized quark gas at finite temperature and density. Specifically we have obtained the electron polarization and the specific heat of magnetized fermions as a functions of the temperature, chemical potential and magnetic field which allow us to study the velocity of the neutron star as a function of these parameters.

  14. Hydrodynamics of gas-liquid slug flow along vertical pipes in turbulent regime-An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Mayor, T.S.; Ferreira, V.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal); Campos, J.B.L.M. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal)], E-mail: jmc@fe.up.pt

    2008-08-15

    An experimental study on free-bubbling gas-liquid (air-water) vertical slug flow was developed using a non-intrusive image analysis technique. The flow pattern in the near-wake of the bubbles and in the main liquid between bubbles was turbulent. A single correlation for the bubble-to-bubble interaction is proposed, relating the trailing bubble velocity to the length of the liquid slug ahead of the bubble. The proposed correlation is shown to be independent of column diameter, column vertical coordinate, superficial liquid and gas velocities and the velocity and length of the leading bubble. Frequency distribution curves, averages, modes and standard deviations are reported, for distributions of bubble velocity, bubble length and liquid slug length, for each experimental condition studied. Good agreement was found between theoretical predictions and experimental results regarding the upward velocity of undisturbed bubbles, in a 0.032 m internal diameter column. A considerable discrepancy was found, though, for a 0.052 m internal diameter column. The acquired experimental data are crucial for the development and validation of a robust slug flow simulator.

  15. Hydrodynamics of gas-liquid slug flow along vertical pipes in turbulent regime-An experimental study

    International Nuclear Information System (INIS)

    Mayor, T.S.; Ferreira, V.; Pinto, A.M.F.R.; Campos, J.B.L.M.

    2008-01-01

    An experimental study on free-bubbling gas-liquid (air-water) vertical slug flow was developed using a non-intrusive image analysis technique. The flow pattern in the near-wake of the bubbles and in the main liquid between bubbles was turbulent. A single correlation for the bubble-to-bubble interaction is proposed, relating the trailing bubble velocity to the length of the liquid slug ahead of the bubble. The proposed correlation is shown to be independent of column diameter, column vertical coordinate, superficial liquid and gas velocities and the velocity and length of the leading bubble. Frequency distribution curves, averages, modes and standard deviations are reported, for distributions of bubble velocity, bubble length and liquid slug length, for each experimental condition studied. Good agreement was found between theoretical predictions and experimental results regarding the upward velocity of undisturbed bubbles, in a 0.032 m internal diameter column. A considerable discrepancy was found, though, for a 0.052 m internal diameter column. The acquired experimental data are crucial for the development and validation of a robust slug flow simulator

  16. Superficial parotidectomy versus retrograde partial superficial parotidectomy in treating benign salivary gland tumor (pleomorphic adenoma).

    Science.gov (United States)

    Emodi, Omri; El-Naaj, Imad Abu; Gordin, Arye; Akrish, Sharon; Peled, Micha

    2010-09-01

    Of all benign salivary gland tumors of the parotid gland, pleomorphic adenoma (mixed tumor) is the most common. It accounts for 60% to 70% of all benign tumors of the parotid gland. This neoplasm arises in patients in the fourth to sixth decade of life, with a female predominance. The surgical excision of this lesion continues to be the subject of major debate. The goal is to avoid facial disability yet attain complete resection without perforation of the capsule/pseudocapsule. The purpose of our study is to compare 2 surgical techniques performed at the Ear, Nose, and Throat and Maxillofacial Departments, Rambam Medical Center, Haifa, Israel, and determine which is preferable in treating this lesion. We reviewed 48 patients who underwent excision of pleomorphic adenoma of the parotid gland between 1996 and 2005 at Rambam Medical Center: 18 were treated surgically with the classical superficial parotidectomy (SP) technique, using an anterograde approach, and 30 were treated with retrograde partial superficial parotidectomy (PSP). We compared the 2 surgical techniques in terms of surgical time, histopathologic size of the lesion, amount of excised healthy parotid tissue, histologic margin, and the preservation of the capsule/pseudocapsule. We also made clinical records of temporary or definitive injury to the facial nerve, which branches of the facial nerve were temporarily or definitively injured, the occurrence of Frey syndrome, esthetic satisfaction, and the amount of recurrence or infection after surgery. Of the 48 patients, 19 (39.6%) were male and 29 (60.4%) were female, with a mean age (+/- SD) of 43.8 +/- 16.97 years (median, 50 years; range, 12-79 years). We found a significant difference (P = .029) in mean surgical time (+/- SD): 171 +/- 49.7 minutes (median, 165 minutes) when performing the classical SP and 145 +/- 42.7 minutes (median, 130 minutes) when performing the retrograde PSP. Much more healthy parotid tissue was taken out with the classical

  17. Gamma Activation Analysis in the Havana Bay superficial sediments

    International Nuclear Information System (INIS)

    Lopez, N.; Gelen, A.; Diaz Riso, O.; Manso, M.V.; Simon, M.J.; Maslov, A.G.; Gustova, M.V.; Beltran, J.; Soto, J.

    2003-01-01

    A preliminary study of 26 elements of Havana Bay superficial sediments were made using Gamma Activation Analysis. Samples from five zones of Havana Bay were analyzed. The results show a close interrelation between the concentration levels of the studied elements and the contaminant sources

  18. Volumetric Modulated Arc Therapy (VMAT) Treatment Planning for Superficial Tumors

    International Nuclear Information System (INIS)

    Zacarias, Albert S.; Brown, Mellonie F.; Mills, Michael D.

    2010-01-01

    The physician's planning objective is often a uniform dose distribution throughout the planning target volume (PTV), including superficial PTVs on or near the surface of a patient's body. Varian's Eclipse treatment planning system uses a progressive resolution optimizer (PRO), version 8.2.23, for RapidArc dynamic multileaf collimator volumetric modulated arc therapy planning. Because the PRO is a fast optimizer, optimization convergence errors (OCEs) produce dose nonuniformity in the superficial area of the PTV. We present a postsurgical cranial case demonstrating the recursive method our clinic uses to produce RapidArc treatment plans. The initial RapidArc treatment plan generated using one 360 o arc resulted in substantial dose nonuniformity in the superficial section of the PTV. We demonstrate the use of multiple arcs to produce improved dose uniformity in this region. We also compare the results of this superficial dose compensation method to the results of a recursive method of dose correction that we developed in-house to correct optimization convergence errors in static intensity-modulated radiation therapy treatment plans. The results show that up to 4 arcs may be necessary to provide uniform dose to the surface of the PTV with the current version of the PRO.

  19. A method for determination of the superficial charge density

    International Nuclear Information System (INIS)

    Vila, F.

    1992-10-01

    In this article is presented a new methodism for determination of superficial charge density in nonconducting materials which is based in the combination of laboratory calibrated experiments in conducting surfaces with theoretical calculations for nonconducting surfaces. (author). 19 refs, 7 figs, 1 tab

  20. Superficial skin infections and the use of topical and systemic ...

    African Journals Online (AJOL)

    Superficial bacterial infections of the skin are very common. With the increasing burden of human immunodeficiency virus (HIV), this is likely to worsen. Examples of such infections include impetigo, erysipelas, cellulitis, ecthyma, furuncles, carbuncles and subcutaneous abscesses. Common causative organisms are ...

  1. Frey′s Syndrome as a Sequela of Superficial Parotidectomy

    Directory of Open Access Journals (Sweden)

    Rishi Kumar Bali

    2006-01-01

    The disorder is characterized by unilateral sweating and flushing of facial skin in the area of parotid gland occurring during meals. We present a case of a patient who developed symptoms of Frey Syndrome 4 months after undergoing superficial parotidectomy on left side.

  2. Diagnostic and therapeutic challenges in superficial CNS siderosis

    DEFF Research Database (Denmark)

    Kondziella, Daniel; Lindelof, M.; Haziri, Donika

    2015-01-01

    the challenges related to the diagnosis and treatment of superficial siderosis. RESULTS: A potential bleeding aetiology was identified in all patients, but removal of the offending bleeding source was achieved only in three (33%). Symptom progression was halted in just one patient (11%), which suggests...... neurotoxicity due to accumulating iron toxicity. FUNDING: not relevant. TRIAL REGISTRATION: not relevant....

  3. Superficial siderosis of the central nervous system | Govind | SA ...

    African Journals Online (AJOL)

    progression of clinical deterioration but halting the chronic subarachoid haemorrhage will reduce the iron load in the CSF and hence the cytotoxic risk. We present a case of superficial siderosis presenting with hearing loss and cerebellar signs highlighting the imaging findings. South African Journal of Radiology Vol.

  4. Treatment for superficial infusion thrombophlebitis of the upper extremity

    NARCIS (Netherlands)

    Di Nisio, Marcello; Peinemann, Frank; Porreca, Ettore; Rutjes, Anne W. S.

    2015-01-01

    Although superficial thrombophlebitis of the upper extremity represents a frequent complication of intravenous catheters inserted into the peripheral veins of the forearm or hand, no consensus exists on the optimal management of this condition in clinical practice. To summarise the evidence from

  5. Risk factors associated with acquiring superficial fungal infections in ...

    African Journals Online (AJOL)

    extensively documented. It is therefore imperative to identify the factors that predispose to the development of SFI so as to provide evidence-based and effective pre- ventive measures, thus reducing the prevalence and the attendant morbidity associated with superficial fungal in- fections and this was our aim in this present ...

  6. Study of Parameters Effect on Hydrodynamics of a Gas-Solid Chamber Experimentally and Numerically

    Directory of Open Access Journals (Sweden)

    Rahimzadeh Hassan

    2012-04-01

    Full Text Available In this research, gas velocity, initial static bed height and particle size effect on hydrodynamics of a non-reactive gas–solid fluidized bed chamber were studied experimentally and computationally. A multi fluid Eulerian model incorporating the kinetic theory for solid particles was applied to simulate the unsteady state behavior of this chamber and momentum exchange coefficients were calculated by using the Syamlal- O’Brien drag functions. Simulation results were compared with the experimental data in order to validate the CFD model. Pressure drops predicted by the simulations at different particle sizes and initial static bed height were in good agreement with experimental measurements at superficial gas velocity higher than the minimum fluidization velocity. Simulation results also indicated that small bubbles were produced at the bottom of the bed. These bubbles collided with each other as they moved upwards forming larger bubbles. Furthermore, this comparison showed that the model can predict hydrodynamic behavior of gas solid fluidized bed chambers reasonably well.

  7. Visualization of two-phase gas-liquid flow regimes in horizontal and slightly-inclined circular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Livia Alves [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: livia@lasme.coppe.ufrj.br; Cunha Filho, Jurandyr; Su, Jian [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Nuclear Engineering Program], Emails: cunhafilho@lasme.coppe.ufrj.br, sujian@lasme.coppe.ufrj.br; Faccini, Jose Luiz Horacio [Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: faccini@ien.gov.br

    2010-07-01

    In this paper a flow visualization study was performed for two-phase gas-liquid flow in horizontal and slightly inclined tubes. The test section consists of a 2.54 cm inner diameter stainless steel circular tube, followed by a transparent acrylic tube with the same inner diameter. The working fluids were air and water, with liquid superficial velocities ranging from 0:11 to 3:28 m/s and gas superficial velocities ranging from 0:27 to 5:48 m/s. Flow visualization was executed for upward flow at 5 deg and 10 deg and downward flow at 2:5 deg, 5 deg and 10 deg, as well as for horizontal flow. The visualization technique consists of a high-speed digital camera that records images at rates of 125 and 250 frames per second of a concurrent air-water mixture through a transparent part of the tube. From the obtained images, the flow regimes were identified (except for annular flow), observing the effect of inclination angles on flow regime transition boundaries. Finally, the experimental results were compared with empirical and theoretical flow pattern maps available in literature. (author)

  8. Major Superficial White Matter Abnormalities in Huntington's Disease

    Science.gov (United States)

    Phillips, Owen R.; Joshi, Shantanu H.; Squitieri, Ferdinando; Sanchez-Castaneda, Cristina; Narr, Katherine; Shattuck, David W.; Caltagirone, Carlo; Sabatini, Umberto; Di Paola, Margherita

    2016-01-01

    Background: The late myelinating superficial white matter at the juncture of the cortical gray and white matter comprising the intracortical myelin and short-range association fibers has not received attention in Huntington's disease. It is an area of the brain that is late myelinating and is sensitive to both normal aging and neurodegenerative disease effects. Therefore, it may be sensitive to Huntington's disease processes. Methods: Structural MRI data from 25 Pre-symptomatic subjects, 24 Huntington's disease patients and 49 healthy controls was run through a cortical pattern-matching program. The surface corresponding to the white matter directly below the cortical gray matter was then extracted. Individual subject's Diffusion Tensor Imaging (DTI) data was aligned to their structural MRI data. Diffusivity values along the white matter surface were then sampled at each vertex point. DTI measures with high spatial resolution across the superficial white matter surface were then analyzed with the General Linear Model to test for the effects of disease. Results: There was an overall increase in the axial and radial diffusivity across much of the superficial white matter (p < 0.001) in Pre-symptomatic subjects compared to controls. In Huntington's disease patients increased diffusivity covered essentially the whole brain (p < 0.001). Changes are correlated with genotype (CAG repeat number) and disease burden (p < 0.001). Conclusions: This study showed broad abnormalities in superficial white matter even before symptoms are present in Huntington's disease. Since, the superficial white matter has a unique microstructure and function these abnormalities suggest it plays an important role in the disease. PMID:27242403

  9. Gas-flow detector for uranium contamination on finned-can surface of a reactor fuel; Detecteur a courant gazeux pour deceler la contamination en uranium des nervures des gaines de combustible nucleaire; Gazopotochnyj detektor zagryazneniya uranom rebristoj poverkhnosti obolochki reaktornykh teplovydelyayushchikh ehlementov; Detector de flujo gaseoso para medir la contaminacion de uranio en la superficie de la vaina de aletas de los elementos combustibles para reactores

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, H; Shiojiri, T; Maeda, Y [Kobe Kogyo Corporation, Okubo, Akashi, Hyogo (Japan)

    1962-04-15

    colectores y el catodo sirve de camara de multiplicacion gaseosa, al igual que en un contador proporcional ordinario. Cada resistencia de 50 k{Omega} separa la capacidad parasita del respectivo colector de las de los otros. La salida del detector se acopla a un amplificador de corriente de baja impedancia de entrada. Esa baja impedancia de entrada tambien contribuye a reducir el efecto nocivo de la capacidad parasita de los circuitos de entrada. Asi se obtiene una relacion senal/ruido conveniente y se facilita una deteccion de particulas alfa con buena sensibilidad. Antes de efectuar una medida se empieza por hacer el vacio en el contador mediante una bomba rotativa y luego se introduce el gas (argon = 90%, metano = 10%). Usando este nuevo equipo, los autores han logrado detectar con exito las particulas alfa emitidas por una contaminacion de 1 x 10{sup -5}g de uranio natural sobre la superficie de una vaina de aletas en un elemento combustible para reactor tipo Calder Hall y de ahora en adelante todos los elementos combustibles destinados al reactor JRR-3 se habran de inspeccionar con el contador descrito. (author) [Russian] EHtot gazopotochnyj detektor predstavlyaet soboyu setochnyj proportsional'nyj schetchik, spetsial'no skonstruirovannyj dlya obnaruzheniya zagryazneniya uranom rebristoj poverkhnosti obolochki reaktornykh teplovydelyayushchikh ehlementov. Obychnyj proportsional'nyj schetchik, sostoyashchij lish' iz katoda i kollektora, vryad li mozhet obnaruzhivat' al'fa-chastitsy, ispuskaemye uranom, zagryaznyayushchim nerovnuyu poverkhnost', kak, naprimer, rebra obolochki reaktornykh teplovydelyayushchikh ehlementov, tak kak ehlektricheskoe pole vblizi takoj poverkhnosti teryaet svoyu odnorodnost'. Po ehtim soobrazheniyam my postroili setochnyj proportsional'nyj schetchik. Ehtot schetchik sostoit iz toplivnogo ehlementa, setki, kollektorov i katoda, skonstruirovannogo v forme tsilindra i raspolozhennogo koaksial'no. Toplivnyj ehlement pomeshchaetsya v seredinu setki i

  10. Water velocity meter

    Science.gov (United States)

    Roberts, C. W.; Smith, D. L.

    1970-01-01

    Simple, inexpensive drag sphere velocity meter with a zero to 6 ft/sec range measures steady-state flow. When combined with appropriate data acquisition system, it is suited to applications where large numbers of simultaneous measurements are needed for current mapping or velocity profile determination.

  11. Estimation of vector velocity

    DEFF Research Database (Denmark)

    2000-01-01

    Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...

  12. experimental investigation of sand minimum transport velocity

    African Journals Online (AJOL)

    user

    The production of reservoir fluid through long tiebacks/pipelines has emerged as one of ... transport in multiphase flows, the investigation of the ... Nigerian Journal of Technology ... associated with water-gas-oil-solid flow in pipeline in ... The mixture was well agitated using a .... operational conditions the limit deposit velocity.

  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. Removal of 14C from nitrogen annulus gas

    International Nuclear Information System (INIS)

    Cheh, C.H.

    1985-01-01

    A dry, ambient temperature process using Ca(OH) 2 as the sorbent to remove 14 CO 2 from moderator cover gas was further developed to remove 14 C from the extremely dry nitrogen annulus gas. Thermal gravimetric analysis was carried out to study the thermal stability of Ca(OH) 2 and the CO 2 -Ca(OH) 2 reaction at elevated temperatures under extremely low humidity conditions. Results shows that to achieve high utilization and avoid decomposition of Ca(OH) 2 , humidification of the annulus gas was necessary at high or low temperatures. Results of the bench scale (1-10 L/min) oxidizer study showed that, with 0.5% Pd or alumina as the catalyst, it was possible to achieve complete oxidation of CO and over 80% oxidation of CH 4 with 1% hydrogen in the nitrogen. The gas superficial velocity should be less than or equal to30 cm/s and the residence time greater than or equal to0.5 s. A pilot scale (up to 160 L/min) system including a catalytic oxidizer, a humidifier/demister, a Ca(OH) 2 reactor, a condenser/demister and regenerable molecular sieve dryers, was assembled and tested with simulated nitrogen annulus gas. Results showed that complete oxidation of the CO and 60-100% oxidation of the CH 4 with 0.5% H 2 in the simulated gas were achieved in the pilot plant. The CO 2 concentration was reduced from 30-60 μL/L at the inlet of the Ca(OH) 2 reactor to 1 μL/L or less at the outlet. After modifications of the dryer to overcome the problems encountered, the simulated annulus gas was dried to 0 C dew point before recirculation. Equipment specifications and operating conditions of a 14 C removal system for nitrogen annulus gas are summarized

  15. An experimental and computational investigation of gas/particle flow in a vertical lifter

    Energy Technology Data Exchange (ETDEWEB)

    Mathisen, Anette

    2010-07-01

    Experimental and computational investigations of dilute gas/particle flow in a vertical lifter are performed. The effect of superficial gas velocity, particle density, particle size distribution and particle loading on particle velocities, particle fluctuations and particle cross-moment have been studied experimentally using laser Doppler anemometry (LDA) and particle image velocimetry (PIV). The results from the experimental investigation is compared with the computational investigation using FluentR. The experimental measurements are performed on a lab-scale vertical lifter, consisting of a fluidizing silo and a receiving tank with a glass pipe in which the solids phase is transported. The particles are placed in the fluidization tank and transport air enters at the bottom of the silo. The transport pipe is suspended above the inlet and as the transport air passes the opening, the particles are dragged into the air flow and transported upwards to the receiving tank. Fluidizing air is used to control the particle loading in the system and supplied through a distribution plate. The test section of the transport pipe is made of glass to enable the use of the optical laser based investigation techniques, LDA and PIV. Two types of powders are used, ZrO{sub 2} and glass, each with two different particle size distributions, average diameter of 260 and 530 micron and 120 and 518 micron, respectively. The experimental techniques LDA and PIV are used to investigate a dilute gas/particle vertical flow. The two techniques are also evaluated for use on this type of flow. LDA is a single point measurement technique, which means that one point is measured at a time. The acquisition stops when a pre-set criteria is reached, this can either be based on sample number or time. A measurement spanning over the whole cross-section of the pipe consists of several points. These points makes up a cross-sectional profile. PIV on the other hand is a whole field technique and consequently

  16. Local liquid velocity measurement in trickle bed reactors (TBRs) using the x-ray digital industrial radiography (DIR) technique

    International Nuclear Information System (INIS)

    Salleh, Khairul Anuar Mohd; Lee, Hyoung Koo; Al-Dahhan, Muthanna H

    2014-01-01

    This work describes the development of a new technique to measure local liquid velocity (V LL ) for multiphase flows in trickle bed reactors (TBRs) (gas–liquid–solid system). In the studied TBR, the liquid phase is represented by water, gas by air and 3 mm expanded polystyrene beads as the solid packing. Three different superficial liquid velocities (V SL ) and a constant superficial gas velocity (V SG ) were used in the packed bed with an internal diameter of 4.25 cm. While the liquid is moving into the packed bed, tracking particles of 106–125 μm diameter (16.45% difference) are injected. The movement of the tracking particles is monitored and digitally recorded by a complementary metal–oxide–semiconductor detector. In this experiment, x-rays were used as the radiation source. Four replications were made with fresh packing. Comparable observations can be found from other published techniques (i.e. magnetic resonance imaging). Results from this study indicate that, at V SL = 0.13 cm s −1 , the measured V LL  can reach up to 51 times that of its V SL , while for V SL = 0.27 cm s −1 , the measured V LL  reached up to 35 times higher than the V SL and for V SL = 0.39 cm s −1 , the V LL  reached up to 39.8 times higher than its V SL . Through statistical analysis, the implementation of such a method is found to be reproducible throughout the experiments. The mean per cent difference in the measured V LL was 10% and 5% for lower implemented V SL   of 0.13 and 0.27 cm s −1 , respectively. At higher V SL  (0.39 cm s −1 ), the particle tracer was greatly distributed and carried away by the high liquid flow rate. The variance or the range of the measured V LL  does not vary for all replications in every V SL , which confirms the reproducibility of the experimental measurements, regardless of the V SL . (paper)

  17. Superficial evolution and compacting aptitude of uranium dioxide powders

    International Nuclear Information System (INIS)

    Danroc, J.

    1982-04-01

    Long term storage of UO 2 powder improves slightly shaping and solidity of compacted powder. The aim of this work is the study of material evolution and the increase of this evolution rate for application to industrial fabrication. Aging in wet air at different temperatures is examined. Evolution of texture and superficial composition is followed. Below 80 0 C UO 3 , 2H 2 O is formed at crystal surface and thermal decomposition gives different hydrates. Kinetics of the transformation is studied. Oxidohydratation in liquid phase is rapid with hydrogen peroxide. The aged or treated material is compacted and mechanical behaviour is examined. Improvement is explained by inter-layer water molecule of the superficial hydrate giving lubricant and pseudo-plastic properties [fr

  18. Ultrasonic velocity measurements in expanded liquid mercury

    International Nuclear Information System (INIS)

    Suzuki, K.; Inutake, M.; Fujiwaka, S.

    1977-10-01

    In this paper we present the first results of the sound velocity measurements in expanded liquid mercury. The measurements were made at temperatures up to 1600 0 C and pressures up to 1700 kg/cm 2 by means of an ultrasonic pulse transmission/echo technique which was newly developed for such high temperature/pressure condition. When the density is larger than 9 g/cm 3 , the observed sound velocity decreases linearly with decreasing density. At densities smaller than 9 g/cm 3 , the linear dependence on the density is no longer observed. The observed sound velocity approaches a minimum near the liquid-gas critical point (rho sub(cr) asymptotically equals 5.5 g/cm 3 ). The existing theories for sound velocity in liquid metals fail to explain the observed results. (auth.)

  19. Isolated core vs. superficial cooling effects on virtual maze navigation.

    Science.gov (United States)

    Payne, Jennifer; Cheung, Stephen S

    2007-07-01

    Cold impairs cognitive performance and is a common occurrence in many survival situations. Altered behavior patterns due to impaired navigation abilities in cold environments are potential problems in lost-person situations. We investigated the separate effects of low core temperature and superficial cooling on a spatially demanding virtual navigation task. There were 12 healthy men who were passively cooled via 15 degrees C water immersion to a core temperature of 36.0 degrees C, then transferred to a warm (40 degrees C) water bath to eliminate superficial shivering while completing a series of 20 virtual computer mazes. In a control condition, subjects rested in a thermoneutral (approximately 35 degrees C) bath for a time-matched period before being transferred to a warm bath for testing. Superficial cooling and distraction were achieved by whole-body immersion in 35 degree water for a time-matched period, followed by lower leg immersion in 10 degree C water for the duration of the navigational tests. Mean completion time and mean error scores for the mazes were not significantly different (p > 0.05) across the core cooling (16.59 +/- 11.54 s, 0.91 +/- 1.86 errors), control (15.40 +/- 8.85 s, 0.82 +/- 1.76 errors), and superficial cooling (15.19 +/- 7.80 s, 0.77 +/- 1.40 errors) conditions. Separately reducing core temperature or increasing cold sensation in the lower extremities did not influence performance on virtual computer mazes, suggesting that navigation is more resistive to cooling than other, simpler cognitive tasks. Further research is warranted to explore navigational ability at progressively lower core and skin temperatures, and in different populations.

  20. Superficial or deep implantation of motor nerve after denervation: an experimental study--superficial or deep implantation of motor nerve.

    Science.gov (United States)

    Askar, Ibrahím; Sabuncuoglu, Bízden Tavíl

    2002-01-01

    Neurorraphy, conventional nerve grafting technique, and artificial nerve conduits are not enough for repair in severe injuries of peripheral nerves, especially when there is separation of motor nerve from muscle tissue. In these nerve injuries, reinnervation is indicated for neurotization. The distal end of a peripheral nerve is divided into fascicles and implanted into the aneural zone of target muscle tissue. It is not known how deeply fascicles should be implanted into muscle tissue. A comparative study of superficial and deep implantation of separated motor nerve into muscle tissue is presented in the gastrocnemius muscle of rabbits. In this experimental study, 30 white New Zealand rabbits were used and divided into 3 groups of 10 rabbits each. In the first group (controls, group I), only surgical exposure of the gastrocnemius muscle and motor nerve (tibial nerve) was done without any injury to nerves. In the superficial implantation group (group II), tibial nerves were separated and divided into their own fascicles. These fascicles were implanted superficially into the lateral head of gastrocnemius muscle-aneural zone. In the deep implantation group (group III), the tibial nerves were separated and divided into their own fascicles. These fascicles were implanted around the center of the muscle mass, into the lateral head of the gastrocnemius muscle-aneural zone. Six months later, histopathological changes and functional recovery of the gastrocnemius muscle were investigated. Both experimental groups had less muscular weight than in the control group. It was found that functional recovery was achieved in both experimental groups, and was better in the superficial implantation group than the deep implantation group. EMG recordings revealed that polyphasic and late potentials were frequently seen in both experimental groups. Degeneration and regeneration of myofibrils were observed in both experimental groups. New motor end-plates were formed in a scattered

  1. Interdigital foot infections: Corynebacterium minutissimum and agents of superficial mycoses

    Directory of Open Access Journals (Sweden)

    Fatma Mutlu Sariguzel

    2014-09-01

    Full Text Available Interdigital foot infections are mostly caused initially by dermatophytes, yeasts and less frequently by bacteria. Erythrasma caused by Corynebacterium minutissimum can be confused with superficial mycoses. The aim of the study was to determine the prevalence of the etiologic agents of superficial mycoses and the frequency of Corynebacterium minutissimum in interdigital foot infections. All the samples obtained from the 121 patients with interdigital foot infections were examined directly with the use of 20% potassium hydroxide mounts and Gram stain under the microscope and cultured on Sabouraud's dextrose agar plates. In identification of superficial mycoses, the rate was found to be 14% with the cultural method and 14% with direct microscopic examination. Using a combination of direct microscopic examination and culture, a 33.8% ratio was achieved. In the culture of these samples, the most isolated factor was Trichophyton rubrum (33.7%. In 24 of the patients (19.8% Corynebacterium minutissimum was detected by Gram staining, in 6 of these patients Trichophyton rubrum was found, Trichophyton mentagrophytes was found in 2 and Trichosporon spp. was found in 1. The examination of interdigital foot lesions in the laboratory, the coexistence of erythrasma with dermatophytes and yeast should be considered.

  2. Superficies in the form of the right to superpose

    Directory of Open Access Journals (Sweden)

    Simona CHIRICĂ

    2015-06-01

    Full Text Available The purpose of this paper is to present the current legal framework related to the superficies right in the form of the right to superpose, and especially to draw the attention and put certain question marks regarding the actuality or even the urgency of the need for regulation regarding the right to superpose. First, as a preliminary aspect, in order to emphasize the historical evolution of the superficies right, we will briefly present the development of this concept starting from the Roman law up to the present date. Second, by analysing the relevant legislation, the doctrine and the jurisprudence, the authors set themselves to present the main methods for constituting the superficies right. Third, the characteristics related to the right to superpose will be correlatively laid out. Fourth, the possibility to obtain a building permit on the basis of the right to superpose will also be analysed. Fifth, the recently entered-into-force legislative framework regarding the registration of the right to superpose and of the building thus erected is presented. Last but not least, the conclusions of this paper are presented, highlighting the necessity for more clearly defined rules regulating the legal status of the right to superpose, in order to avoid any confusions and inconsistencies in practice.

  3. Velocity Feedback Experiments

    Directory of Open Access Journals (Sweden)

    Chiu Choi

    2017-02-01

    Full Text Available Transient response such as ringing in a control system can be reduced or removed by velocity feedback. It is a useful control technique that should be covered in the relevant engineering laboratory courses. We developed velocity feedback experiments using two different low cost technologies, viz., operational amplifiers and microcontrollers. These experiments can be easily integrated into laboratory courses on feedback control systems or microcontroller applications. The intent of developing these experiments was to illustrate the ringing problem and to offer effective, low cost solutions for removing such problem. In this paper the pedagogical approach for these velocity feedback experiments was described. The advantages and disadvantages of the two different implementation of velocity feedback were discussed also.

  4. 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.

  5. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys

    International Nuclear Information System (INIS)

    Silva, Edmara Marques Rodrigues da

    2001-01-01

    The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO 2 laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the level of

  6. CFD-DEM Simulation of Minimum Fluidisation Velocity in Two Phase Medium

    Directory of Open Access Journals (Sweden)

    H Khawaja

    2016-09-01

    Full Text Available In this work, CFD-DEM (computational fluid dynamics - discrete element method has been used to model the 2 phase flow composed of solid particle and gas in the fluidised bed. This technique uses the Eulerian and the Langrangian methods to solve fluid and particles respectively. Each particle is treated as a discrete entity whose motion is governed by Newton's laws of motion. The particle-particle and particle-wall interaction is modelled using the classical contact mechanics. The particles motion is coupled with the volume averaged equations of the fluid dynamics using drag law. In fluidised bed, particles start experiencing drag once the fluid is passing through. The solid particles response to it once drag experienced is just equal to the weight of the particles. At this moment pressure drop across the bed is just equal to the weight of particles divide by the cross-section area. This is the first regime of fluidization, also referred as ‘the regime of minimum fluidization’. In this study, phenomenon of minimum fluidization is studied using CFD-DEM simulation with 4 different sizes of particles 0.15 mm, 0.3 mm, 0.6 mm, and 1.2 mm diameters. The results are presented in the form of pressure drop across the bed with the fluid superficial velocity. The achieved results are found in good agreement with the experimental and theoretical data available in literature.

  7. Phase velocity enhancement of linear explosive shock tubes

    Science.gov (United States)

    Loiseau, Jason; Serge, Matthew; Szirti, Daniel; Higgins, Andrew; Tanguay, Vincent

    2011-06-01

    Strong, high density shocks can be generated by sequentially detonating a hollow cylinder of explosives surrounding a thin-walled, pressurized tube. Implosion of the tube results in a pinch that travels at the detonation velocity of the explosive and acts like a piston to drive a shock into the gas ahead of it. In order to increase the maximum shock velocities that can be obtained, a phase velocity generator can be used to drag an oblique detonation wave along the gas tube at a velocity much higher than the base detonation velocity of the explosive. Since yielding and failure of the gas tube is the primary limitation of these devices, it is desirable to retain the dynamic confinement effects of a heavy-walled tamper without interfering with operation of the phase velocity generator. This was accomplished by cutting a slit into the tamper and introducing a phased detonation wave such that it asymmetrically wraps around the gas tube. This type of configuration has been previously experimentally verified to produce very strong shocks but the post-shock pressure and shock velocity limits have not been investigated. This study measured the shock trajectory for various fill pressures and phase velocities to ascertain the limiting effects of tube yield, detonation obliquity and pinch aspect ratio.

  8. Video Measurement of the Muzzle Velocity of a Potato Gun

    Science.gov (United States)

    Jasperson, Christopher; Pollman, Anthony

    2011-01-01

    Using first principles, a theoretical equation for the maximum and actual muzzle velocities for a pneumatic cannon was recently derived. For a fixed barrel length, this equation suggests that the muzzle velocity can be enhanced by maximizing the product of the initial pressure and the volume of the propellant gas and decreasing the projectile…

  9. An investigation on near wall transport characteristics in an adiabatic upward gas-liquid two-phase slug flow

    Science.gov (United States)

    Zheng, Donghong; Che, Defu

    2007-08-01

    The near-wall transport characteristics, inclusive of mass transfer coefficient and wall shear stress, which have a great effect on gas-liquid two-phase flow induced internal corrosion of low alloy pipelines in vertical upward oil and gas mixing transport, have been both mechanistically and experimentally investigated in this paper. Based on the analyses on the hydrodynamic characteristics of an upward slug unit, the mass transfer in the near wall can be divided into four zones, Taylor bubble nose zone, falling liquid film zone, Taylor bubble wake zone and the remaining liquid slug zone; the wall shear stress can be divided into two zones, the positive wall shear stress zone associated with the falling liquid film and the negative wall shear stress zone associated with the liquid slug. Based on the conventional mass transfer and wall shear stress characteristics formulas of single phase liquid full-pipe turbulent flow, corrected normalized mass transfer coefficient formula and wall shear stress formula are proposed. The calculated results are in good agreement with the experimental data. The shear stress and the mass transfer coefficient in the near wall zone are increased with the increase of superficial gas velocity and decreased with the increase of superficial liquid velocity. The mass transfer coefficients in the falling liquid film zone and the wake zone of leading Taylor bubble are lager than those in the Taylor bubble nose zone and the remaining liquid slug zone, and the wall shear stress associated falling liquid film is larger than that associated the liquid slug. The mass transfer coefficient is within 10-3 m/s, and the wall shear stress below 103 Pa. It can be concluded that the alternate wall shear stress due to upward gas-liquid slug flow is considered to be the major cause of the corrosion production film fatigue cracking.

  10. Functional compartmentalization of the human superficial masseter muscle.

    Directory of Open Access Journals (Sweden)

    Rodrigo A Guzmán-Venegas

    Full Text Available Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM muscle's motor units using high-density surface electromyography (EMGs at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF were randomly requested. Using a two-dimensional grid (four columns, six electrodes located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001.The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001. The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001. The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20-60% MVBF.

  11. [Occupational trauma due to superficial corneal foreign body].

    Science.gov (United States)

    Gerente, Vanessa Miroski; Melo, Gustavo Barreto de; Regatieri, Caio Vinícius Saito; Alvarenga, Lênio Souza; Martins, Elizabeth Nogueira

    2008-01-01

    To evaluate the epidemiology of superficial corneal foreign body. Patients who were seen at the Emergency Service of the Federal University of São Paulo, from April/05 to June/05, were screened and those with superficial corneal foreign body were interviewed. Data regarding gender, age, occupation, employment status, availability and use of protective devices and supervision of their use were collected. Awareness of the possible complications was also assessed. Results were analyzed using chi-square or Fisher exact test. One hundred twenty-three patients were interviewed. Only 3 patients were female. The mean age was 36 years. Most injuries occurred at the workplace (86.2%), and 58.4% of the patients did not have a legal employment registration. The occupational activities most frequently reported were construction related activities (44.3%) and welding/soldering (11.3%). In most workplaces (79.8%) protective devices were available and 85.3% of the patients were instructed to use them. A safety device was being used during the accident in 34.2% of the cases and this was more frequent among patients that had legal employment registry (p=0.008) and among those under supervision (p=0.0415). The majority of the patients (68.9%) were aware of the risk of severe complications. Most patients with superficial corneal foreign body are aware of its severe complications and injuries usually occur in places where safety devices are available and often during their use. Our findings suggest that prevention should focus on supervision and correct use of safety devices.

  12. Modified circular velocity law

    Science.gov (United States)

    Djeghloul, Nazim

    2018-05-01

    A modified circular velocity law is presented for a test body orbiting around a spherically symmetric mass. This law exhibits a distance scale parameter and allows to recover both usual Newtonian behaviour for lower distances and a constant velocity limit at large scale. Application to the Galaxy predicts the known behaviour and also leads to a galactic mass in accordance with the measured visible stellar mass so that additional dark matter inside the Galaxy can be avoided. It is also shown that this circular velocity law can be embedded in a geometrical description of spacetime within the standard general relativity framework upon relaxing the usual asymptotic flatness condition. This formulation allows to redefine the introduced Newtonian scale limit in term of the central mass exclusively. Moreover, a satisfactory answer to the galactic escape speed problem can be provided indicating the possibility that one can also get rid of dark matter halo outside the Galaxy.

  13. Superficial thrombophlebitis (Mondor′s Disease after breast augmentation surgery

    Directory of Open Access Journals (Sweden)

    Viana Giovanni Andre

    2008-01-01

    Full Text Available Although the aetiology of Mondor′s disease remains unclear, the most commonly cited cause is trauma of some sort. Although surgical trauma has frequently been quoted, reports that specifically implicate aesthetic breast surgery are unusual in the literature. In this article, the authors report a case of superficial thrombophlebitis of the anterolateral chest wall secondary to breast augmentation surgery in a woman, five months after the procedure. The authors performed an analysis of the disease′s main etiologic components and preponderant clinical aspects, and determined all appropriate therapeutic measures.

  14. High dose rate brachytherapy for superficial cancer of the esophagus

    International Nuclear Information System (INIS)

    Maingon, Philippe; D'Hombres, Anne; Truc, Gilles; Barillot, Isabelle; Michiels, Christophe; Bedenne, Laurent; Horiot, Jean Claude

    2000-01-01

    Purpose: We analyzed our experience with external radiotherapy, combined modality treatment, or HDR brachytherapy alone to limited esophageal cancers. Methods and Materials: From 1991 to 1996, 25 patients with limited superficial esophagus carcinomas were treated by high dose rate brachytherapy. The mean age was 63 years (43-86 years). Five patients showed superficial local recurrence after external radiotherapy. Eleven patients without invasion of the basal membrane were staged as Tis. Fourteen patients with tumors involving the submucosa without spreading to the muscle were staged as T1. Treatment consisted of HDR brachytherapy alone in 13 patients, external radiotherapy and brachytherapy in 8 cases, and concomitant chemo- and radiotherapy in 4 cases. External beam radiation was administered to a total dose of 50 Gy using 2 Gy daily fractions in 5 weeks. In cases of HDR brachytherapy alone (13 patients), 6 applications were performed once a week. Results: The mean follow-up is 31 months (range 24-96 months). Twelve patients received 2 applications and 13 patients received 6 applications. Twelve patients experienced a failure (48%), 11/12 located in the esophagus, all of them in the treated volume. One patient presented an isolated distant metastasis. In the patients treated for superficial recurrence, 4/5 were locally controlled (80%) by brachytherapy alone. After brachytherapy alone, 8/13 patients were controlled (61%). The mean disease-free survival is 14 months (1-36 months). Overall survival is 76% at 1 year, 37% at 2 years, and 14% at 3 years. Overall survival for Tis patients is 24% vs. 20% for T1 (p 0.83). Overall survival for patients treated by HDR brachytherapy alone is 43%. One patient presented with a fistula with local failure after external radiotherapy and brachytherapy. Four stenosis were registered, two were diagnosed on barium swallowing without symptoms, and two required dilatations. Conclusion: High dose rate brachytherapy permits the treating

  15. Modelos de mantenimiento y reemplazo de equipos en mineria superficial

    OpenAIRE

    Llanque Maquera, Oscar Eloy; Llanque Maquera, Oscar Eloy

    1999-01-01

    El mantenimiento y reemplazamiento de equipos en Minería Superficie tiene una gran importada por el mismo hecho que se mueven volumen de material y por las altas inversiones hechas en maquinaria, a su vez por la influencia en los costos de operación. Por tal razón es el interés en desarrollar los modelos de mantenimiento y reemplazamiento de equipos en minería e implemento el mantenimiento predictivo, como una actividad complementaria a los mantenimientos que se realizan comúnmente como son p...

  16. Speed, Acceleration, and Velocity: Level II, Unit 9, Lesson 1; Force, Mass, and Distance: Lesson 2; Types of Motion and Rest: Lesson 3; Electricity and Magnetism: Lesson 4; Electrical, Magnetic, and Gravitational Fields: Lesson 5; The Conservation and Conversion of Matter and Energy: Lesson 6; Simple Machines and Work: Lesson 7; Gas Laws: Lesson 8; Principles of Heat Engines: Lesson 9; Sound and Sound Waves: Lesson 10; Light Waves and Particles: Lesson 11; Program. A High.....

    Science.gov (United States)

    Manpower Administration (DOL), Washington, DC. Job Corps.

    This self-study program for high-school level contains lessons on: Speed, Acceleration, and Velocity; Force, Mass, and Distance; Types of Motion and Rest; Electricity and Magnetism; Electrical, Magnetic, and Gravitational Fields; The Conservation and Conversion of Matter and Energy; Simple Machines and Work; Gas Laws; Principles of Heat Engines;…

  17. STUDY OF GAS SEPARATION PROCESS BY DYNAMIC ADSORPTION IN FIXED BED

    Directory of Open Access Journals (Sweden)

    Ioan Solomon

    2010-10-01

    Full Text Available An experimental study of mass transfer at gas separation by dynamic adsorption in fixed bed of impregnated silica gel is presented in this work. By means of a mathematical model based on constants and coefficient easy to evaluate, the distributions of adsorbate concentration in gas and solid phases were determined as a function of time and throughout the height of the fixed bed, under isothermal conditions.With this aim, water vapors from air were adsorbed in a fixed bed of impregnated silica gel. The values of the volumetric mass transfer coefficient, Kv, were determined experimentally at several values of air superficial velocity, an air relative humidity of 69�20at 38 °C. The influence of the gas flow velocity and initial water concentration in adsorbent on the distribution of water concentration in both phases was established as a function of time and throughout the height of the fixed bed. The results obtained allow one to determination of the local adsorption rate.

  18. Drift velocity monitoring of the CMS muon drift chambers

    CERN Document Server

    Sonnenschein, Lars

    2010-01-01

    The drift velocity in drift tubes of the CMS muon chambers is a key parameter for the muon track reconstruction and trigger. It needs to be monitored precisely in order to detect any deviation from its nominal value. A change in absolute pressure, a variation of the gas admixture or a contamination of the chamber gas by air affect the drift velocity. Furthermore the temperature and magnetic field influence its value. First data, taken with a dedicated Velocity Drift Chamber (VDC) built by RWTH Aachen IIIA are presented.

  19. The Prescribed Velocity Method

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    The- velocity level in a room ventilated by jet ventilation is strongly influenced by the supply conditions. The momentum flow in the supply jets controls the air movement in the room and, therefore, it is very important that the inlet conditions and the numerical method can generate a satisfactory...

  20. Multidisc neutron velocity selector

    International Nuclear Information System (INIS)

    Rosta, L.; Zsigmond, Gy.; Farago, B.; Mezei, F.; Ban, K.; Perendi, J.

    1987-12-01

    The prototype of a velocity selector for neutron monochromatization in the 4-20 A wavelength range is presented. The theoretical background of the multidisc rotor system is given together with a description of the mechanical construction and electronic driving system. The first tests and neutron measurements prove easy handling and excellent parameters. (author) 6 refs.; 7 figs.; 2 tabs

  1. Optical coherence tomography and polarimetry of superficial skin biopsies

    Directory of Open Access Journals (Sweden)

    S. R. Utz

    2015-01-01

    Full Text Available The goal. Of this study was to develop and assess the efficacy of polarization probing of biotissues in vitro. The method is based on the determination of polarization parameters of scattered radiation. Materials and methods. The well-known superficial epidermis stripping method was applied using the Sulfacrylate self-sterile medical adhesive. Small portions of thin layers of the adhesive were applied to slide plates and then to different skin sites. The corneous layer in the normal condition and in case of skin diseases (psoriasis, lichen acuminatus, discoid lupus erythematosus, alopecia, itching and demodectic mange was examined based on the optical coherence tomography (OCT method using the 0CS1300SS device (Thorlabs Inc, USA. Results. The authors obtained pictures visualizing the structural organization of different layers of the epidermis using the superficial epidermis biopsy method in case of lichen acuminatus, hyperkeratosis, itching and other skin diseases. Conclusion. This method ensures non-invasive high-precision measurement of the structure of different layers of the epidermis, which may be useful both for research purposes and practical dermatology.

  2. Superficially located enlarged lymphoid follicles characterise nodular gastritis.

    Science.gov (United States)

    Okamura, Takuma; Sakai, Yasuhiro; Hoshino, Hitomi; Iwaya, Yugo; Tanaka, Eiji; Kobayashi, Motohiro

    2015-01-01

    Nodular gastritis is a form of chronic Helicobacter pylori gastritis affecting the gastric antrum and characterised endoscopically by the presence of small nodular lesions resembling gooseflesh. It is generally accepted that hyperplasia of lymphoid follicles histologically characterises nodular gastritis; however, quantitative analysis in support of this hypothesis has not been reported. Our goal was to determine whether nodular gastritis is characterised by lymphoid follicle hyperplasia.The number, size, and location of lymphoid follicles in nodular gastritis were determined and those properties compared to samples of atrophic gastritis. The percentages of high endothelial venule (HEV)-like vessels were also evaluated.The number of lymphoid follicles was comparable between nodular and atrophic gastritis; however, follicle size in nodular gastritis was significantly greater than that seen in atrophic gastritis. Moreover, lymphoid follicles in nodular gastritis were positioned more superficially than were those in atrophic gastritis. The percentage of MECA-79 HEV-like vessels was greater in areas with gooseflesh-like lesions in nodular versus atrophic gastritis.Superficially located hyperplastic lymphoid follicles characterise nodular gastritis, and these follicles correspond to gooseflesh-like nodular lesions observed endoscopically. These observations suggest that MECA-79 HEV-like vessels could play at least a partial role in the pathogenesis of nodular gastritis.

  3. Lactic acid peeling in superficial acne scarring in Indian skin.

    Science.gov (United States)

    Sachdeva, Silonie

    2010-09-01

    Chemical peeling with both alpha and beta hydroxy acids has been used to improve acne scarring with pigmentation. Lactic acid, a mild alpha hydroxy acid, has been used in the treatment of various dermatological indications but no study is reported in acne scarring with pigmentation. To evaluate the efficacy and safety of full strength pure lactic acid 92% (pH 2.0) chemical peel in superficial acne scarring in Indian skin. Seven patients, Fitzpatrick skin type IV-V, in age group 20-30 years with superficial acne scarring were enrolled in the study. Chemical peeling was done with lactic acid at an interval of 2 weeks to a maximum of four peels. Pre- and post-peel clinical photographs were taken at every session. Patients were followed every month for 3 months after the last peel to evaluate the effects. At the end of 3 months, there was definite improvement in the texture, pigmentation, and appearance of the treated skin, with lightening of scars. Significant improvement (greater than 75% clearance of lesions) occurred in one patient (14.28%), good improvement (51-75% clearance) in three patients (42.84%), moderate improvement (26-50% clearance) in two patients (28.57%), and mild improvement (1-25% clearance) in one patient (14.28%). © 2010 Wiley Periodicals, Inc.

  4. Superficial corneal crosslinking during laser in situ keratomileusis.

    Science.gov (United States)

    Seiler, Theo G; Fischinger, Isaak; Koller, Tobias; Derhartunian, Viktor; Seiler, Theo

    2015-10-01

    To determine the safety of superficial corneal crosslinking after laser in situ keratomileusis (LASIK). Institut für Refraktive und Ophthalmo-Chirurgie, Zurich, Switzerland. Prospective study. Eyes with an ectasia risk score of 2 or higher were treated with standard LASIK (90 μm flap) for myopia correction, after which a rapid corneal crosslinking was performed in the interface (riboflavin 0.5% for 2 minutes, 9 mW/cm(2) for 5 minutes) (Group 1). The follow-up was up to 1 year. The prevalence of complications was statistically compared with that in a group of eyes matched regarding age, sex, and attempted refractive correction that were treated with standard LASIK only (Group 2). One month postoperatively, 5 eyes in Group 1 lost 1 line of corrected distance visual acuity (CDVA) compared with 1 eye in Group 2 (P rate of less than 5%. The refractive success was identical in both groups. Early postoperative complications such as erosions (16%), diffuse lamellar keratitis (DLK) stage 1 (38%), and DLK stage 2 (5%) were statistically significantly more frequent after superficial corneal crosslinking, leading to a statistically significantly reduced uncorrected distance visual acuity at 1 month (P interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  5. Local superficial hyperthermia in combination with low-dose radiation therapy for palliation of superficially localized metastases

    International Nuclear Information System (INIS)

    Owczarek, G.; Miszczyk, L.

    2005-01-01

    Full text: The aim of this study is to evaluate the response of superficially located metastases and local toxicity to microwave hyperthermia combined with radiation therapy. From May 2003 through December 2004 58 patients (33 male, 25 female; mean age 60 years) with lymph nodes or skin metastases were treated with microwave superficial hyperthermia combined with low-dose radiation therapy. Hyperthermia was administered twice weekly with high frequency applicator (∼900 Mhz) with water bolus. The temperature was set to 43 o C for 45 minutes. Radiotherapy was performed daily with dose 2 Gy or 4 Gy per fraction, to a total dose 20 Gy. There were 47 patients with carcinoma, 4 with sarcoma, 7 with melanoma. Treated regions were: head and neck (37 patients), chest wall 8, abdomen wall and groins 4, upper and lower limb 2 and 8 patients respectively. Primary tumor sites were: head and neck region (9 patients), lung 15, alimentary tract 8, breast 5, soft tissue 8, urogenital 4 and 9 patients with primary tumor site unknown. The toxicity was evaluated using 6 step scale: 0-no skin reaction, 1-faint red mark, 2-distinct red mark, 3-blisters, 4-brown mark, 5-necrosis. Presence of pain and its intensity were also analyzed. Diameter of tumor after the treatment was observed. Complete response was achieved in 5 patients (8.5 %), and partial response in 29 patients (50 %), no response was observed in 12 patients (20 %) and progression of tumor in 7 patients (12 %). No skin reaction was observed in 3 patients, faint red mark in 14 patients, distinct red mark in 28 patients, blisters in 8 patients, brown mark in 4 patients and necrosis in 1 patient. The pain occurred in 9 patients but it was no the cause of stopping treatment. Local superficial hyperthermia combined with low-dose radiation therapy is an effective method of treatment in a proportion of patients with superficial metastases. This combination of treatment modalities is well tolerated and is useful for palliation

  6. Critical ionisation velocity effects in astrophysical plasmas

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1979-08-01

    Critical ionisation velocity effects are relevant to astrophysical situations where neutral gas moves through a magnetised plasma. The experimental significance of the critical velocity is well established and the physical basis is now becoming clear. The underlying mechanism depends on the combined effects of electron impact ionisation and electron energisation by collective plasma interactions. For low density plasmas a theory based on a circular process involving electron heating through a modified two stream instability has been developed. Several applications of critical velocity effects to astrophysical plasmas have been discussed in the literature. The importance of the effect in any particular case may be determined from a detailed consideration of energy and momentum balance, using appropriate atomic rate coefficients and taking full account of collective plasma processes. (Auth.)

  7. Systematic measurement of electron drift velocity and study of some properties of four gas mixtures: A-CH4, A-C2H4, A-C2H6, A-C3H8

    International Nuclear Information System (INIS)

    Jean-Marie, B.; Lepeltier, V.; L'Hote, D.

    1978-06-01

    Systematic measurements of the electron drift velocity have been made for four argon-hydrocarbon vapour mixtures: argon-methane, argon-ethylene, argon-ethane, argon-propane and values of the electric field ranging from 0.3 to 4KV/cm. The results are analysed in terms of stability and 'saturation' of the drift speed. The effects of the electron diffusion are also investigated

  8. The superficial ulnar artery: development and clinical significance Artéria ulnar superficial: desenvolvimento e relevância clínica

    Directory of Open Access Journals (Sweden)

    Srinivasulu Reddy

    2007-09-01

    Full Text Available The principal arteries of the upper limb show a wide range of variation that is of considerable interest to orthopedic surgeons, plastic surgeons, radiologists and anatomists. We present here a case of superficial ulnar artery found during the routine dissection of right upper limb of a 50-year-old male cadaver. The superficial ulnar artery originated from the brachial artery, crossed the median nerve anteriorly and ran lateral to this nerve and the brachial artery. The superficial ulnar artery in the arm gave rise to a narrow muscular branch to the biceps brachii. At the elbow level the artery ran superficial to the bicipital aponeurosis where it was crossed by the median cubital vein. It then ran downward and medially superficial to the forearm flexor muscles, and then downward to enter the hand. At the palm, it formed the superficial and deep palmar arches together with the branches of the radial artery. The presence of a superficial ulnar artery is clinically important when raising forearm flaps in reconstructive surgery. The embryology and clinical significance of the variation are discussed.As principais artérias do membro superior apresentam uma ampla variação, que é relativamente importante a cirurgiões ortopédicos e plásticos, radiologistas e anatomistas.Apresentamosumcaso de artéria ulnar superficial encontrada durante dissecção de rotina de membro superior direito de um cadáver masculino de 50 anos de idade.Aartéria ulnar superficial originava-se da artéria braquial, cruzava o nervo mediano anteriormente e percorria lateralmente esse nervo e a artéria braquial. A artéria ulnar superficial no braço deu origem a um ramo muscular estreito do músculo bíceps braquial. Ao nível do cotovelo, a artéria percorria superficialmente a aponeurose bicipital, onde era cruzada pela veia cubital mediana. Percorria, então, em sentido descendente e medialmente superficial aos músculos flexores do antebraço, e então descendia para

  9. Almacenamiento de gas natural

    Directory of Open Access Journals (Sweden)

    Tomás Correa

    2008-12-01

    Full Text Available The largest reserves of natural gas worldwide are found in regions far of main cities, being necessary different alternatives to transport the fluid to the consumption cities, such as pipelines, CNG or ships, LNG, depending on distances between producing regions and demanding regions and the producing volumes. Consumption regions have three different markets to naturalgas; residential and commercial, industrial and power generation sector. The residential and commercial is highly seasonal and power generation sector is quite variable depending on increases of temperature during summer time. There are also external issuesthat affect the normal gas flow such as fails on the national system or unexpected interruptions on it, what imply that companies which distribute natural gas should design plans that allow supplying the requirements above mentioned. One plan is using underground natural gas storage with capacities and deliverability rates enough to supply demands. In Colombia there are no laws in this sense but it could be an exploration to discuss different ways to store gas either way as underground natural gas storage or above superficies. Existing basically three different types of underground natural gas storage; depleted reservoirs, salt caverns and aquifers. All ofthem are adequate according to geological characteristics and the needs of the distributors companies of natural gas. This paper is anexploration of technical and economical characteristics of different kind of storages used to store natural gas worldwide.

  10. Ultrasonic Surface Measurements for the investigation of superficial alteration of natural stones

    Science.gov (United States)

    Meier, Thomas; Auras, Michael; Bilgili, Filiz; Christen, Sandra; Cristiano, Luigia; Krompholz, Rolf; Mosca, Ilaria; Rose, David

    2013-04-01

    Seismic waveform analysis is applicable also to the centimeter and decimeter scale for non-destructive testing of pavement, facades, plaster, sculptures, or load-bearing structures like pillars. Mostly transmission measurements are performed and travel-times of first arriving P-waves are considered that have limited resolution for the upper centimeters of an object. In contrast, surface measurements are well suited to quantify superficial alterations of material properties e.g. due to weathering. A number of surface measurements have been carried out in the laboratory as well as on real structures in order to study systematically the information content of ultrasonic waveforms and their variability under real conditions. As a preposition for ultrasonic waveform analysis, reproducible, broad-band measurements have to be carried out with a definite radiation pattern and an about 1 mm accuracy of the measurement geometry. We used special coupling devices for effective ultrasonic surface measurements in the laboratory as well as at real objects. Samples of concrete with varying composition and samples of natural stone - marble, tuff, and sandstone - were repeatedly weathered and tested by ultrasonic measurements. The resistance of the samples to weathering and the penetration depth of the weathering are analyzed. Furthermore, material specific calibration curves for changes in velocities of elastic waves due to weathering can be obtained by these tests. Tests on real structures have been carried out for marble (Schlossbrücke, Berlin) and sandstone (Porta Nigra, Trier). Altogether, these test measurements show clearly that despite of the internal inhomogeneity of many real objects, their surface roughness and topography especially ultrasonic Rayleigh waves are well suited to study material alterations in the upper centimeters. Dispersion of Rayleigh waves may be inverted for shear-wave velocity as a function of depth.

  11. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States). Dept. of Mechanical Engineering

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  12. Multidisk neutron velocity selectors

    International Nuclear Information System (INIS)

    Hammouda, B.

    1992-01-01

    Helical multidisk velocity selectors used for neutron scattering applications have been analyzed and tested experimentally. Design and performance considerations are discussed along with simple explanation of the basic concept. A simple progression is used for the inter-disk spacing in the 'Rosta' design. Ray tracing computer investigations are presented in order to assess the 'coverage' (how many absorbing layers are stacked along the path of 'wrong' wavelength neutrons) and the relative number of neutrons absorbed in each disk (and therefore the relative amount of gamma radiation emitted from each disk). We discuss whether a multidisk velocity selector can be operated in the 'reverse' configuration (i.e. the selector is turned by 180 0 around a vertical axis with the rotor spun in the reverse direction). Experimental tests and calibration of a multidisk selector are reported together with evidence that a multidisk selector can be operated in the 'reverse' configuration. (orig.)

  13. Application of the carbon dioxide-barium hydroxide hydrate gas-solid reaction for the treatment of dilute carbon dioxide-bearing gas streams

    International Nuclear Information System (INIS)

    Haag, G.L.

    1983-09-01

    The removal of trace components from gas streams via irreversible gas-solid reactions in an area of interest to the chemical engineering profession. This research effort addresses the use of fixed beds of Ba(OH) 2 hydrate flakes for the removal of an acid gas, CO 2 , from air that contains approx. 330 ppM/sub v/ CO 2 . Areas of investigation encompassed: (1) an extensive literature review of Ba(OH) 2 hydrate chemistry, (2) microscale studies on 0.150-g samples to develop a better understanding of the reaction, (3) process studies at the macroscale level with 10.2-cm-ID fixed-bed reactors, and (4) the development of a model for predicting fixed-bed performance. Experimental studies indicated fixed beds of commercial Ba(OH) 2 .8H 2 O flakes at ambient temperatures to be capable of high CO 2 -removal efficiencies (effluent concentrations 99%), and an acceptable pressure drop (1.8 kPa/m at a superficial gas velocity of 13 cm/s). Ba(OH) 2 .8H 2 O was determined to be more reactive toward CO 2 than either Ba(OH) 2 .3H 2 O or Ba(OH) 2 .1H 2 O. A key variable in the development of this fixed-bed process was relative humidity. Operation at conditions with effluent relative humidities >60% resulted in significant recrystallization and restructuring of the flake and subsequent pressure-drop problems

  14. Two Crosslinking Technologies for Superficial Reticular Dermis Injection: A Comparative Ultrasound and Histologic Study

    OpenAIRE

    Micheels, Patrick; Besse, Stéphanie; Sarazin, Didier

    2017-01-01

    Background: Few hyaluronic acid fillers have been developed for superficial injection. Objective: To compare the diffusion and integration properties of cohesive polydensified matrix and Vycross® technology hyaluronic acid fillers with lidocaine following injection into the superficial reticular dermis. Methods and materials: Two subjects received two injections each of cohesive polydensified matrix and Vycross® hyaluronic acid (0.2mL/site) in the superficial reticular dermis of the buttock u...

  15. Myxoid stroma and delicate vasculature of a superficial angiomyxoma give rise to the red planet sign

    OpenAIRE

    Green, Margaret; Logemann, Nichola; Sulit, Daryl J

    2014-01-01

    Superficial angiomyxomas are uncommon benign mesenchymal tumors. They often recur locally if partially removed. This case report demonstrates not only the characteristic pathological findings of a superficial angiomyxoma in a 33- year-old man, but also shows a unique dermatoscopic image, which in our estimation resembles a celestial red planet such as the blood moon seen during a lunar eclipse. We propose to call this the “red planet” sign for a superficial angiomyxoma on dermoscopic examinat...

  16. Myxoid stroma and delicate vasculature of a superficial angiomyxoma give rise to the red planet sign.

    Science.gov (United States)

    Green, Margaret; Logemann, Nichola; Sulit, Daryl J

    2014-09-16

    Superficial angiomyxomas are uncommon benign mesenchymal tumors. They often recur locally if partially removed. This case report demonstrates not only the characteristic pathological findings of a superficial angiomyxoma in a 33- year-old man, but also shows a unique dermatoscopic image, which in our estimation resembles a celestial red planet such as the blood moon seen during a lunar eclipse. We propose to call this the "red planet" sign for a superficial angiomyxoma on dermoscopic examination.

  17. Structure of the gas-liquid annular two-phase flow in a nozzle section

    International Nuclear Information System (INIS)

    Yoshida, Kenji; Kataoka, Isao; Ohmori, Syuichi; Mori, Michitsugu

    2006-01-01

    Experimental studies on the flow behavior of gas-liquid annular two-phase flow passing through a nozzle section were carried out. This study is concerned with the central steam jet injector for a next generation nuclear reactor. In the central steam jet injector, steam/water annular two-phase flow is formed at the mixing nozzle. To make an appropriate design and to establish the high-performance steam injector system, it is very important to accumulate the fundamental data of the thermo-hydro dynamic characteristics of annular flow passing through a nozzle section. On the other hand, the transient behavior of multiphase flow, in which the interactions between two-phases occur, is one of the most interesting scientific issues and has attracted research attention. In this study, the transient gas-phase turbulence modification in annular flow due to the gas-liquid phase interaction is experimentally investigated. The annular flow passing through a throat section is under the transient state due to the changing cross sectional area of the channel and resultantly the superficial velocities of both phases are changed compared with a fully developed flow in a straight pipe. The measurements for the gas-phase turbulence were precisely performed by using a constant temperature hot-wire anemometer, and made clear the turbulence structure such as velocity profiles, fluctuation velocity profiles. The behavior of the interfacial waves in the liquid film flow such as the ripple or disturbance waves was also observed. The measurements for the liquid film thickness by the electrode needle method were also performed to measure the base film thickness, mean film thickness, maximum film thickness and wave height of the ripple or the disturbance waves. (author)

  18. Microseismic Velocity Imaging of the Fracturing Zone

    Science.gov (United States)

    Zhang, H.; Chen, Y.

    2015-12-01

    Hydraulic fracturing of low permeability reservoirs can induce microseismic events during fracture development. For this reason, microseismic monitoring using sensors on surface or in borehole have been widely used to delineate fracture spatial distribution and to understand fracturing mechanisms. It is often the case that the stimulated reservoir volume (SRV) is determined solely based on microseismic locations. However, it is known that for some fracture development stage, long period long duration events, instead of microseismic events may be associated. In addition, because microseismic events are essentially weak and there exist different sources of noise during monitoring, some microseismic events could not be detected and thus located. Therefore the estimation of the SRV is biased if it is solely determined by microseismic locations. With the existence of fluids and fractures, the seismic velocity of reservoir layers will be decreased. Based on this fact, we have developed a near real time seismic velocity tomography method to characterize velocity changes associated with fracturing process. The method is based on double-difference seismic tomography algorithm to image the fracturing zone where microseismic events occur by using differential arrival times from microseismic event pairs. To take into account varying data distribution for different fracking stages, the method solves the velocity model in the wavelet domain so that different scales of model features can be obtained according to different data distribution. We have applied this real time tomography method to both acoustic emission data from lab experiment and microseismic data from a downhole microseismic monitoring project for shale gas hydraulic fracturing treatment. The tomography results from lab data clearly show the velocity changes associated with different rock fracturing stages. For the field data application, it shows that microseismic events are located in low velocity anomalies. By

  19. Understanding the three-dimensional anatomy of the superficial lymphatics of the limbs.

    Science.gov (United States)

    Tourani, Saam S; Taylor, G Ian; Ashton, Mark W

    2014-11-01

    There are minimal data in the current literature regarding the depth of the superficial lymphatic collectors of the limbs in relation to the various subcutaneous tissue layers. Injection, microdissection, radiographic, and histologic studies of the superficial lymphatics and the subcutaneous tissues of 32 limbs from 15 human cadavers were performed. Five layers were consistently identified in the integument of all the upper and lower limb specimens: (1) skin, (2) subcutaneous fat, (3) superficial fascia, (4) loose areolar tissue, and (5) deep fascia. Layer 2 was further divided into superficial (2a) and deep (2c) compartments by a thin, transparent, horizontal septum (layer 2b). The main superficial veins and the superficial nerves coursed in layer 4. The lymphatic collectors were found at layer 2c and layer 4. The use of consistent nomenclature to describe the subcutaneous tissue layers facilitates a greater understanding and discussion of the anatomy. In lymphovenous anastomosis for the treatment of lymphedema, indocyanine green lymphography is an unreliable method for identification of the superficial collectors of the thigh. The medial proximal leg, the dorsum of the wrist over the anatomical snuffbox, and the volar proximal forearm provide suitable areas for locating superficial collectors with nearby matching size veins. In vertical medial thigh lift, choosing a dissection plane superficial to the great saphenous vein is unlikely to preserve the collectors of the ventromedial bundle.

  20. Superficies de titanio en implantes dentales de carga inmediata

    OpenAIRE

    Aparicio, C.; Padrós, A.; Planell Estany, Josep Anton; Gil, F.J.

    2008-01-01

    Se ha obtenido una capa de fosfato de calcio del mismo contenido mineral que el hueso en la superficie del implante dental de titanio, que tiene como consecuencia una muy rápida y eficaz osteointegración. Esta capa se ha obtenido mediante un método biomimético por vía termoquímica. La capa se une al substrato por enlace químico. Este hecho evita todos los inconvenientes de los métodos de recubrimiento convencionales (plasma spray, ablación láser...) cuya unión es por interacción mecánica, lo ...

  1. Photoluminescence of acupoint 'Waiqiu' in human superficial fascia

    International Nuclear Information System (INIS)

    Zhang Yuan; Yan Xiaohui; Liu Chenglin; Dang Ruishan; Zhang Xinyi

    2006-01-01

    The spectral characters of an acupuncture point named 'Waiqiu' in superficial fascia tissue have been studied by photoluminescence (PL) spectroscopy under the excitation of 457.9 nm. The PL around 'Waiqiu' acupuncture point consists of two sub-bands resulting from the flavin adenine dinucleotide (FAD) and phospholipids, and the porphyrins (including purine, isoxanthopterin and tryptophan), respectively. More emission due to FAD and phospholipids is found inside the acupuncture effect area of 'Waiqiu' than its marginal or outside acupuncture regions. The ratio of emission intensity of FAD and phospholipids to one of porphyrins gradually decreases along the direction away from the center of the acupuncture point. It implies that the component proportion changes between FAD, phospholipids and porphyrins around the 'Waiqiu' acupuncture point. We suggest that there might be a certain relationship between redox function of FAD and 'Waiqiu' acupuncture effect

  2. Transient superficial peroneal nerve palsy after anterior cruciate ligament reconstruction

    Directory of Open Access Journals (Sweden)

    Majed Alrowaili

    2016-06-01

    Full Text Available A 19-year-old male subject was diagnosed with medial meniscal, lateral meniscal and anterior cruciate ligament (ACL tear. The symptoms did not subside after 4 months of physical therapy, and he underwent arthroscopic partial medial and lateral meniscectomy and ACL reconstruction. Immediately after the patient woke up from general anesthesia, he started experience loss of sensation in the area of superficial peroneal nerve with inverted dorsiflexion of foot and ankle. Instantly, the bandage and knee brace was removed and a diagnosis of compartment syndrome was ruled out. After eight hours, post-operatively, the patient started receiving physiotherapy. He complained of numbness and tingling in the same area. After 24 h, post-operatively, the patient started to regain dorsiflexion and eversion gradually. Two days after the surgery, the patient exhibited complete recovery of neurological status.

  3. Superficial Granulomatous Pyoderma Gangrenosum of the Penis: A Case Report

    Directory of Open Access Journals (Sweden)

    Shyamala S. Gopi

    2006-01-01

    Full Text Available Classic type of pyoderma gangrenosum (PG is an uncommon ulceronecrotic cutaneous disease of uncertain aetiology characterised by broad zones of confluent ulceration with violaceous undermined margins. Some 50% of cases are associated with systemic diseases. The superficial granulomatous variant of pyoderma gangrenosum (SGPG of the external genitalia is extremely rare Patients with this condition develop single or multiple ulcerated skin lesions often with sinus tract formation. The majority of these lesions were found on the trunk and limbs. SGPG is less likely to be associated with underlying disease processes than classic PG. We present a 58 year-old with recalcitrant penile ulceration demonstrated to be SGPG on biopsy. Although rare and poorly recognised, the histological features are sufficiently typical to allow the correct diagnosis to be established.

  4. Superficial plantar cutaneous sensation does not trigger barefoot running adaptations.

    Science.gov (United States)

    Thompson, M A; Hoffman, K M

    2017-09-01

    It has long been proposed that the gait alterations associated with barefoot running are mediated by alterations in sensory feedback, yet there has been no data to support this claim. Thus, the purpose of this study was to examine the role of superficial plantar cutaneous feedback in barefoot and shod running. 10 healthy active subjects (6 male, 4 female); mass: 65.2+9.7kg; age: 27+7.1years participated in this study. 10 over-ground running trials were completed in each of the following conditions: barefoot (BF), shod (SHOD), anesthetized barefoot (ANEST BF) and anesthetized shod (ANEST SHOD). For the anesthetized conditions 0.1-0.3mL of 1% lidocaine was injected into the dermal layer of the plantar foot below the metatarsal heads, lateral column and heel. 3-dimensional motion analysis and ground reaction force (GRF) data were captured as subjects ran over a 20m runway with a force plate at 12m. Kinematic and kinetic differences were analyzed via two-way repeated measure ANOVAs. The differences in gait between the BF and SHOD conditions were consistent with previous research, with subjects exhibiting a significant decrease in stride length and changing from rearfoot strike when SHOD to fore/midfoot strike when BF. Additionally, BF running was associated with decreased impact peak magnitudes and peak vertical GRFs. Despite anesthetizing the plantar surface, there was no difference between the BF and ANEST BF conditions in terms of stride length, foot strike or GRFs. Superficial cutaneous sensory receptors are not primarily responsible for the gait changes associated with barefoot running. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Excimer laser superficial keratectomy for proud nebulae in keratoconus.

    Science.gov (United States)

    Moodaley, L; Liu, C; Woodward, E G; O'Brart, D; Muir, M K; Buckley, R

    1994-06-01

    Contact lens intolerance in keratoconus may be due to the formation of a proud nebula at or near the apex of the cone. Excimer laser superficial keratectomy was performed as an outpatients with proud nebulae as treatment patients with proud nebulae as treatment for their contact lens intolerance. The mean period of contact lens wear before the development of intolerance was 13.4 years (range 2 to 27 years). Following the development of intolerance, three patients abandoned contact lens wear in the affected eye while the remainder experienced a reduction in comfortable wearing time (mean = 3.75 hours; range: 0-14 hours). All patients had good potential Snellen visual acuity with a contact lens of 6/9 (nine eyes) and 6/12 (one eye). The proud nebulae were directly ablated with a 193 nm ArF excimer laser using a 1 mm diameter beam. Between 100-150 pulses were sufficient to ablate the raised area. Patients experienced no pain during the procedure and reported minimal discomfort postoperatively. In all cases flattening of the proud nebulae was achieved. Seven patients were able to resume regular contact lens wear (mean wearing time = 10.17 hours; range 8 to 16 hours). In three patients, resumption of contact lens wear was unsuccessful because of cone steepness. All patients achieved postoperative Snellen visual acuity of 6/12 or better with a contact lens. Four patients experienced a loss of one line in Snellen acuity. The mean follow up period was 8.3 months (range 2 to 17 months). Excimer laser superficial keratectomy is a useful technique for the treatment of contact lens intolerance caused by proud nebulae in patients with keratoconus. Penetrating keratoplasty is thus avoided.

  6. Evolution of the structure of a gas-liquid two-phase flow in a large vertical pipe

    International Nuclear Information System (INIS)

    Horst-Michael Prasser; Matthias Beyer; Helmar Carl; Sabine Gregor; Dirk Lucas; Peter Schuetz; Frank-Peter Weiss

    2005-01-01

    Full text of publication follows: Experimental results on the evolution of the radial gas fraction profiles, gas velocity profiles and bubble size distributions in a gas-liquid two-phase flow along a large vertical pipe of 194 mm inner diameter are presented. The tests were performed at the TOPFLOW facility in Rossendorf, where two wire-mesh sensors were used to measure sequences of two-dimensional distributions of local instantaneous gas fraction within the complete pipe cross-section with a lateral resolution of 3 mm and a sampling frequency of 2500 Hz. This data is the basis for a fast flow visualization and for the calculation of the mentioned profiles. The gas fraction profiles were obtained by averaging the sequences over time, velocities were measured by cross-correlation of the signals of the two sensors, which were located on a short (63 mm) distance behind each other. The high resolution of the mesh sensors allows to identify regions of connected measuring points in the data array, which are filled with the gas phase. This method was used to obtain the bubble size distributions. In the experiments, the superficial velocities ranged from 0.04 to 8 m/s for the gas phase and from 0.04 to 1.6 m/s for the liquid. In this way, the experiments cover the range from bubbly to churn turbulent flow regimes. The evolution of the flow structure was studied by varying the distance between the gas injection and the sensor position. This distance was changed by the help of a so-called variable gas injection set-up. It consists of 6 gas injection units, each of them equipped with three rings of orifices in the pipe wall for the gas injection. These rings are fed with the gas phase from ring chambers, which can be individually controlled by valves. The middle ring has orifices of 4 mm diameter, while the upper and the lower rings have nozzles of 1 mm diameter. In this way, 18 different inlet lengths and two different gas injection geometries can be chosen. The latter

  7. Evaluation analysis of correlations for predicting the void fraction and slug velocity of slug flow in an inclined narrow rectangular duct

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Chaoxing, E-mail: yanchaoxing0808@163.com [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001 (China); Yan, Changqi, E-mail: Changqi_yan@163.com [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001 (China); Shen, Yunhai [Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610041 (China); Sun, Licheng; Wang, Yang [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001 (China)

    2014-07-01

    Highlights: • 46 void fraction correlations are evaluated on void fraction. • Evaluation of void fraction correlations on slug velocity is studied. • Effect of void fraction correlations on separated frictional pressure drop is studied. • Drift-flux type correlation shows best agreement with experimental data. • Evaluation is investigated in different flow regions. - Abstract: A visualized investigation was conducted on inclined upward air–water slug flow in a narrow rectangular duct with the cross section of 43 mm × 3.25 mm. The slug velocity and void fraction were obtained through image processing. 46 correlations for predicting void fraction, covering the types of slip ratio, Kβ, Lockhart and Martinelli, drift-flux and general were evaluated against the experimental data. In the experiment, four inclined conditions including 0°, 10°, 20° and 30° were investigated and the ranges of gas and liquid superficial velocity were 0.16–2.63 m/s and 0.12–3.59 m/s, respectively. The results indicate that the inclination has no significant influence on prediction error for a given correlation and the drift-flux type correlations are more competitive than the others in the prediction of slug velocity and void fraction. In addition, most of drift-flux type correlations are quite accurate in turbulent flow region, while they provide relative poor predictions in laminar flow region. As for the frictional pressure drop separated from the measured total pressure drop, the deviation arising from the calculation of the void fraction by different correlations is significant in laminar flow region, whereas is negligible in turbulent flow region.

  8. Numerical simulation of gas-liquid two-phase flow and convective heat transfer in a micro tube

    International Nuclear Information System (INIS)

    Fukagata, Koji; Kasagi, Nobuhide; Ua-arayaporn, Poychat; Himeno, Takehiro

    2007-01-01

    Numerical simulation of an air and water two-phase flow in a 20 μm ID tube is carried out. A focus is laid upon the flow and heat transfer characteristics in bubble-train flows. An axisymmetric two-dimensional flow is assumed. The finite difference method is used to solve the governing equations, while the level set method is adopted for capturing the interface of gas and liquid. In each simulation, the mean pressure gradient and the wall heat flux are kept constant. The simulation is repeated under different conditions of pressure gradient and void fraction. The superficial Reynolds numbers of gas and liquid phases studied are 0.34-13 and 16-490, respectively, and the capillary number is 0.0087-0.27. Regardless of the flow conditions, the gas-phase velocity is found approximately 1.2 times higher than the liquid-phase velocity. This is in accordance with the Armand correlation valid for two-phase flows in macro-sized tubes. The two-phase friction coefficient is found to be scaled with the Reynolds number based on the effective viscosity of the Einstein type. The computed wall temperature distribution is qualitatively similar to that observed experimentally in a mini channel. The local Nusselt number beneath the bubble is found notably higher than that of single-phase flow

  9. PIV Measurements of Gas Flow Fields from Burning End

    Science.gov (United States)

    Huang, Yifei; Wu, Junzhang; Zeng, Jingsong; Tang, Darong; Du, Liang

    2017-12-01

    To study the influence of cigarette gas on the environment, it is necessary to know the cigarette gas flow fields from burning end. By using PIV technique, in order to reveal velocity characteristics of gas flow fields, the velocities of cigarette gas flow fields was analyzed with different stepping motor frequencies corresponding to suction pressures, and the trend of velocity has been given with image fitting. The results shows that the velocities of the burning end increased with suction pressures; Between velocities of the burning end and suction pressures, the relations present polynomial rule; The cigarette gas diffusion in combustion process is faster than in the smoldering process.

  10. Void fraction for gas bubbling in shallow viscous pools-application to molten core concrete interaction

    International Nuclear Information System (INIS)

    Journeau, C.; Haquet, J.F.

    2005-01-01

    During Molten Core-Concrete Interaction, the concrete will release gases (mainly steam and carbon oxides) that will flow through the corium pool. To obtain reliable heat transfer prediction, it is necessary to model the void fraction in the pool as a function of the gas mass flow (or superficial velocity at the interface). A series of simulant-materials have been performed with water-air and sugar syrup-air in order to study how the drift model could be applied to a shallow pool (where the bubbly flow is not fully developed) and to liquids which are more viscous (with higher Morton numbers) than water. The bubble average diameter was estimated around 3 mm with spherical to ellipsoidal shapes. For all the configurations, even with the shallowest pools (6 cm height for 38 cm diameter) the experimental void fractions follow the drift-model relationship. In water, the distribution coefficient C 0 tends to the classical value of 1.2 while the drift velocity V jg tends to the 23 cm/s predicted by Ishii (1975) model for churn flows. For the more viscous syrup, the drift velocity tends to 13 cm/s which is significantly lower than the value obtained from the Ishii correlation for bubbly or churn flows (established for water). These results are then applied to MCCI experimental configurations. (authors)

  11. Examples of Vector Velocity Imaging

    DEFF Research Database (Denmark)

    Hansen, Peter M.; Pedersen, Mads M.; Hansen, Kristoffer L.

    2011-01-01

    To measure blood flow velocity in vessels with conventional ultrasound, the velocity is estimated along the direction of the emitted ultrasound wave. It is therefore impossible to obtain accurate information on blood flow velocity and direction, when the angle between blood flow and ultrasound wa...

  12. Medicina regenerativa y superficie ocular Regenerative medicine and ocular surface

    Directory of Open Access Journals (Sweden)

    Taimi Cárdenas Díaz

    2012-06-01

    Full Text Available En los últimos años se ha producido un extraordinario avance en los conocimientos relacionados con diferentes ramas biomédicas, entre ellas, la biología celular. Esto ha dado un notable impulso a una nueva rama de la medicina denominada medicina regenerativa. Esta nueva disciplina médica se basa fundamentalmente en los nuevos conocimientos sobre las células madre y en su capacidad de convertirse en células de diferentes tejidos. Una de las estructuras que tiene más interés, desde el punto de vista de la medicina regenerativa, es la superficie ocular. Por esto, se ha logrado notables progresos en la reconstrucción de la superficie ocular mediante la aplicación de procederes regenerativos. Los cultivos de células del epitelio corneal humano están siendo utilizados en el tratamiento de la insuficiencia limbar. Esto permite disminuir la incidencia de opacidades tipo Haze tras queratectomía fotorrefractiva, acelerar la curación y evitar la aparición de leucomas en pacientes con defectos epiteliares persistentes e intentar disminuir la incidencia de opacidades corneales en pacientes sometidos a queratectomía fototerapéutica por diferentes distrofias corneales.In the last few years, an extraordinary advance has taken place in the knowledge about several biomedical branches as is the case of cellular biology, which has remarkably encouraged the development of a new medical branch called regenerative medicine. This medical discipline is fundamentally based on the new knowledge on the stem cells and their capacity to become cells for different tissues. One of the most interesting structures for the regenerative medicine is the ocular surface. In the last few years, significant advances have been achieved in the field of the ocular surface reconstruction with regenerative procedures. Some cell cultures of the human corneal epithelium are being used to treat limber insufficiency, to reduce the incidence of haze-type opacities after

  13. 5-Aminolevulinic acid photodynamic therapy for superficial basal cell carcinoma

    International Nuclear Information System (INIS)

    Want, David; Kennedy, James C.; Brundage, Michael; Rothwell, Deanna

    1997-01-01

    Treatment of superficial basal cell carcinoma with topical 5-aminolevulinic acid photodynamic therapy (ALA-PDT) offers an alternative to plastic surgery and radiotherapy with potential for good cosmetic outcome and local control of disease. We report our clinical experience with this technique. Patients were treated prospectively on a study protocol enrolling a total of 118 patients (63 male, 55 female) with an average age of 65 years. Consecutive patients meeting eligibility criteria were invited to participate over a four year period. Median followup was 27 months (range 1 to 76 months). In the study group, 62 patients had single lesions and 56 had multiple lesions. Of the 56 patients with multiple lesions, 33 had 2-4 lesions, 11 had 5-9, and 11 had 10 or more. All patients were treated with 20% ALA dissolved in Glaxal Base applied to the tumors for three to four hours. Following removal of the cream, fluorescence intensity and distribution were assessed using a UV-A lamp, and the lesions were exposed to photoactivating light of wavelength greater than 600 nm for a light dose ranging from 100-150 J/cm2. Lesions were reassessed in followup, and scored as complete or partial responses. At subsequent patient assessments, lesions were scored as continued complete responses or recurrences. In the patients with single lesions, there was an initial complete response rate of 90.3%. Of the 56 patients with multiple lesions, 44 had all of their lesions respond completely, and there was an overall average response rate of 95.5%. Sixty three percent of males and 44% of females had all of their lesions respond completely. (p=0.033, Chi-squared test). There was no difference in response rate with respect to age, or site of lesion. The recurrence rates were 35% for patients with single lesions, and 10.5% for patients with multiple lesions. ALA-PDT would appear to be a promising alternative to conventional treatment for superficial basal cell carcinoma. Based on these results

  14. Spinal meningeal melanocytoma and hydrocephalus and intracranial superficial siderosis

    International Nuclear Information System (INIS)

    Das, A.; Ratnagopal, P.; Puvanendran, K.; Teo, J.G.C.

    2001-01-01

    Meningeal melanocytomas are uncommon tumours of the central nervous system; fewer than 50 cases have been reported in the English literature. We review the unique clinical presentation, radiological appearance and histological features of a rare case of meningeal melanocytoma. The patient was a 50-year-old man with a history of hypertension who presented with complaints of severe headache, nausea, vomiting and blurry vision for 2 days. Clinical examination revealed no hyperpigmentation marks and he had no history of regressed skin melanocytic lesions. Apart from mild terminal neck stiffness, his general medical examination was unremarkable. On funduscopic examination he had marked bilateral papilloedema and the blind spots were enlarged bilaterally. His neurological examination was otherwise unremarkable. A magnetic resonance imaging scan (MRI) of the brain showed hydrocephalus. On the precontrast T 2 -weighted images, there was hyperintensity of the meninges with little change after administration of gadolinium, which was suggestive of blood. On the T 2 -weighted sequences, there was evidence of hypo-i intensity on the surface of the pons and medulla, which was indicative of superficial siderosis

  15. Current status of superficial pharyngeal squamous cell carcinoma in Japan.

    Science.gov (United States)

    Rikitake, Ryoko; Ando, Mizuo; Saito, Yuki; Yoshimoto, Seiichi; Yamasoba, Tatsuya; Higashi, Takahiro

    2017-10-01

    To investigate the status and treatment of superficial pharyngeal squamous cell carcinoma in Japan. We analyzed all cases diagnosed between 2011 and 2013, as recorded in the national database of hospital-based cancer registries. We extracted data on patient sex, age, tumor locations, histology, presentation routes, initial treatments, and TNM stages. Additionally, we compared the characteristics of pharyngeal carcinoma to those of esophageal cancer. A total of 16,521 oropharyngeal and hypopharyngeal cancers from 409 institutions were included. Diagnosis of Tis tumors was infrequent, and both cancers were likely to be diagnosed at an advanced stage (n = 866, 5.3%). Tis diseases were the most commonly detected during follow-up examinations for other diseases (n = 608, 70%). While more oropharyngeal Tis patients were men compared to T1-4 patients (88 vs 82%, respectively), hypopharyngeal cancer patients comprised an equally high proportion of men (94 vs 92%, respectively). The most common location of oropharyngeal Tis tumors was the posterior wall (32%), whereas T1-4 tumors were most commonly found on the lateral wall (36%). In hypopharyngeal cancer, both Tis and T1-4 were most commonly located in the pyriform sinus (62%). The proportion of Tis tumors diagnosed at individual institutions showed a positive correlation with the number of endoscopic treatments (r = 0.32, P squamous cell carcinoma patients in Japan. Further improvements in early diagnosis and standardized treatments are warranted.

  16. Superficial effects during the activation of zirconium AB2 alloys

    International Nuclear Information System (INIS)

    Zerbino, J; Visitin, A; Triaca, W

    2005-01-01

    The activation of zirconium nickel alloys with and without the addition of chromium and titanium is investigated through electrochemical and optical techniques.These alloys show high hydrogen absorption capacity and are extensively used in metal hydride batteries.Recent investigations in aqueous 1 M KOH indicate oxide layer growth and occlusion of hydrogen species in the alloys during the application of different cathodic potential programmes currently used in the activation process.In this research several techniques such as voltammetry, ellipsometry, energy dispersive analysis of X-rays EDAX, and scanning electron microscopy SEM are applied on the polished massive alloy Zr 1 -xTi x , x=0.36 y 0.43, and Zr 1 -xTi x CrNi, x=0.1,0.2 y 0.4.Data analysis shows that the stability, compactness and structure of the passive layers are strongly dependent on the applied potential programme.The alloy activation depends on the formation of deepen crevices that remain after a new polishing. Microscopic observation shows increase in the crevices thickness after the cathodic sweep potential cycling, which produces fragmentation of the grains and oxide growth during the activation process.This indicates metal breaking and intergranular dissolution that take place together with oxide and hydride formation.In some cases the resultant crevice thickness is one or two orders higher than that of the superficial oxide growth indicating intergranular localised corrosion

  17. Experimental Study of Phlebitis Ointment Administration in Acute Superficial Thrombophlebitis

    Directory of Open Access Journals (Sweden)

    Guangzong Li

    2018-01-01

    Full Text Available Acute superficial thrombophlebitis is a venous system disease. Animal models with mannitol induced phlebitis were treated with an orally administered “phlebitis ointment.” 24 rabbits were randomly divided into 4 groups. The therapy group was treated with “phlebitis ointment” and a control group received “Mai Luo Shu Tong granules.” Levels of blood TNF-α, IL-6, CRP, and IL-1β were measured. The tissue expression levels of NF-КBp65 and PKC genes were evaluated. The therapy group showed a better improvement of the clinical status and similar vascular morphology than the control group. A blank group showed no vascular changes through pathological investigation. In contrast, significant vascular changes were seen in the model group. The control group showed slight vascular modifications. Small thrombi could be found in the lumen despite the intact tunica intima. Both control and therapy group showed less inflammatory cells infiltration than the model group and upregulation of NF-КBp65 and PKC genes. The phlebitis ointment reduced the levels of necrosis factor-α, interleukin-6, C-reactive protein, and interleukin-1ß. The expressions of NF-КBp65 and PKC genes, which are the primary mechanisms underlying the development of thrombophlebitis, were improved significantly in tissues of both therapy group and control group.

  18. Superficial vessel reconstruction with a multiview camera system

    Science.gov (United States)

    Marreiros, Filipe M. M.; Rossitti, Sandro; Karlsson, Per M.; Wang, Chunliang; Gustafsson, Torbjörn; Carleberg, Per; Smedby, Örjan

    2016-01-01

    Abstract. We aim at reconstructing superficial vessels of the brain. Ultimately, they will serve to guide the deformation methods to compensate for the brain shift. A pipeline for three-dimensional (3-D) vessel reconstruction using three mono-complementary metal-oxide semiconductor cameras has been developed. Vessel centerlines are manually selected in the images. Using the properties of the Hessian matrix, the centerline points are assigned direction information. For correspondence matching, a combination of methods was used. The process starts with epipolar and spatial coherence constraints (geometrical constraints), followed by relaxation labeling and an iterative filtering where the 3-D points are compared to surfaces obtained using the thin-plate spline with decreasing relaxation parameter. Finally, the points are shifted to their local centroid position. Evaluation in virtual, phantom, and experimental images, including intraoperative data from patient experiments, shows that, with appropriate camera positions, the error estimates (root-mean square error and mean error) are ∼1  mm. PMID:26759814

  19. Internet: Más Allá de la superficie

    Directory of Open Access Journals (Sweden)

    Diego Andrés Tovar Cardozo

    2015-01-01

    Full Text Available El presente artículo expone un enfoque técnico de la Internet que da a conocer algunas características de su estructura, la cual muestra dos sectores distintos en donde se puede encontrar la información, es decir, esta se encuentra distribuida en niveles o capas de manera parcial o restringida, integrada o desagregada, todo ello dependiendo de lo que el usuario requiera realmente. La forma correcta para acceder a la información requerida está en saber a dónde ir a buscarla, la web profunda es información no visible para el usuario común que no tiene la habilidad de búsqueda, por lo cual se hace necesario verificar el tipo, la calidad y veracidad de la información a obtener antes de proceder a usar la información encontrada con los buscadores tradicionales. Acceder a Internet sin saber que existe una falsa cortina utilizada por la mayoría de los buscadores convencionales, es limitar las capacidades de navegar en un océano de información valiosa, en ello radica la importancia de conocer la web desde lo superficial (Surface Web a lo profundo (Deep Web.

  20. Inmersiones condicionadas de grafos en superficies y seudosuperficies.

    Directory of Open Access Journals (Sweden)

    Fedriani Martel, E. M.

    1999-01-01

    Full Text Available En este trabajo se procede a recapitular resultados conocidos sobre el problema de caracterizar los grafos que admiten inmersiones en superficies y en seudosuperficies con todos los vértices en la misma cara y se da una caracterización original de los grafos con dicha propiedad en seudosuperficies que surgen de manera natural y que han sido tratadas en la literatura especializada. Se comienza desarrollando algunos conceptos necesarios para la exposición de los problemas que se tratan, pero se suponen conocidos otros básicos de la Teoría de Grafos. Los resultados relacionados llevan de forma consecuente al planteamiento de otros problemas cuyas resoluciones originales también se incluyen. En cuanto a los objetivos finales que se pretenden lograr con esta comunicación, se basan, sobre todo, en aprovechar los resultados obtenidos por la Teoría de Grafos para resolver problemas pertenecientes a otras áreas, como la Economía. Se termina exponiendo un motivo topológico por el que estos estudios sobre las inmersiones y las inmersiones peri-S se hallan próximas a la Economía.

  1. Fine-needle aspiration cytology in children with superficial lymphadenopathy

    Directory of Open Access Journals (Sweden)

    F. De Corti

    2014-04-01

    Full Text Available Introduction: In pediatric population Fine-Needle Aspiration Citology (FNAC is slowly gaining acceptance in clinical management of Superficial Lymphadenopathy (SL. Our experience adds some data about the usefulness of this technique in diagnosing the cause of a SL and therefore guiding further treatment. Patients and Methods: 238 FNAC were performed in 217 patients with SL, observed at our Institution from 2002 to 2006. The neck was the most frequent localization. The results were available within few hours. In cases of granulomatous findings, the samples were processed for microbiological and PCR test, in order to identify Mycobacteria. Results: 174 were reactive lesions, 38 granulomatous lymphadenopathies, 24 malignant lesions, 2 specimens inadequate for diagnosis. Among the 174 reactive SL, 22 required an incisional biopsy after 1 month follow-up. Among the granulomatous lymphadenopathies, 13 children with Cat-Scratch Disease recovered, 25 with Mycobacteria infection underwent surgical excision. For 24 malignant lesions, the diagnosis was confirmed by further biopsy. Two false negative and no false positive were detected (sensitivity 92%, specificity 100%. No complications were encountered. Conclusions: In our experience FNAC, performed by experienced cytopathologist, has revealed to be a fast, safe, non invasive and inexpensive method to achieve diagnosis in persistent SL. The use of FNAC gave us the possibility to select patients for further investigation and/or surgical treatment. Incisional biopsy remains necessary to confirm the diagnosis in case of malignancy or doubtful lesions.

  2. Triterpenes for Well-Balanced Scar Formation in Superficial Wounds

    Directory of Open Access Journals (Sweden)

    Stefan Kindler

    2016-08-01

    Full Text Available Triterpenes are demonstrably effective for accelerating re-epithelialisation of wounds and known to improve scar formation for superficial lesions. Among the variety of triterpenes, betuline is of particular medical interest. Topical betuline gel (TBG received drug approval in 2016 from the European Commission as the first topical therapeutic agent with the proven clinical benefit of accelerating wound healing. Two self-conducted randomized intra-individual comparison clinical studies with a total of 220 patients involved in TBG treatment of skin graft surgical wounds have been screened for data concerning the aesthetic aspect of wound healing. Three months after surgery wound treatment with TBG resulted in about 30% of cases with more discreet scars, and standard of care in about 10%. Patients themselves appreciate the results of TBG after 3 months even more (about 50% compared to standard of care (about 10%. One year after surgery, the superiority of TBG counts for about 25% in comparison with about 10%, and from the patients’ point of view, for 25% compared to 4% under standard of care. In the majority of wound treatment cases, there is no difference visible between TBG treatment and standard of care after 1 year of scar formation. However, in comparison, TBG still offers a better chance for discreet scars and therefore happens to be superior in good care of wounds.

  3. Superficial chemical peeling with salicylic acid in facial dermatoses

    International Nuclear Information System (INIS)

    Bari, A.U.; Iqbal, Z.; Rahman, S.B.

    2007-01-01

    To determine the effectiveness of salicylic acid chemical peeling in common dermatological conditions affecting face in people with predominant Fitzpatrick skin type IV and V. A total of 167 patients of either gender, aged between 13 to 60 years, having some facial dermatoses (melasma, acne vulgaris, postinflammatory hyperpigmentations, freckles, fine lines and wrinkles, post-inflammatory scars, actinic keratoses, and plane facial warts) were included. A series of eight weekly hospital based peeling sessions was conducted in all patients under standardized conditions with 30% salicylic acid. Clinical improvement in different disorders was evaluated by change in MASI score, decrease in the size of affected area and % reduction in lesions count. McNemar test was applied for data analysis. Majority of the patients showed moderate to excellent response. There was 35% to 63% improvement (p< 0.05) in all dermatoses. Significant side effects, as feared in Asian skins were not observed. Chemical peeling with salicylic acid is an effective and safe treatment modality in many superficial facial dermatoses. (author)

  4. Multivectored Superficial Muscular Aponeurotic System Suspension for Facial Paralysis.

    Science.gov (United States)

    Leach, Garrison; Kurnik, Nicole; Joganic, Jessica; Joganic, Edward

    2017-06-01

    Facial paralysis is a devastating condition that may cause severe cosmetic and functional deformities. In this study we describe our technique for superficial muscular aponeurotic system (SMAS) suspension using barbed suture and compare the vectors of suspension in relation to the underlying musculature. This study also quantifies the improvements in postoperative symmetry using traditional anthropologic landmarks. The efficacy of this procedure for improving facial paralysis was determined by comparing anthropometric indices and using Procrustes distance between 4 groupings of homologous landmarks plotted on each patient's preoperative and postoperative photos. Geometric morphometrics was used to evaluate change in facial shape and improvement in symmetry postoperatively.To analyze the vector of suspension in relation to the underlying musculature, specific anthropologic landmarks were used to calculate the vector of the musculature in 3 facial hemispheres from cadaveric controls against the vector of repair in our patients. Ten patients were included in our study. Subjectively, great improvement in functional status was achieved. Geometric morphometric analysis demonstrated a statistically significant improvement in facial symmetry. Cadaveric dissection demonstrated that the suture should be placed in the SMAS in vectors parallel to the underlying musculature to achieve these results. There were no complications in our study to date. In conclusion, multivectored SMAS suture suspension is an effective method for restoring static suspension of the face after facial paralysis. This method has the benefit of producing quick, reliable results with improved function, low cost, and low morbidity.

  5. DRENAGEM SUPERFICIAL DE SOLOS ARGILOSOS DO NORTE DO PARANÁ

    Directory of Open Access Journals (Sweden)

    Rogério Teixeira de Faria

    1999-08-01

    Full Text Available RESUMO Foi avaliado o desempenho de práticas de drenagem superficial e cobertura morta em uma área de várzea do norte do Paraná. Antes e após o cultivo do arroz, foram comparadas as taxas de drenagem em tratamentos com e sem drenos torpedo e determinadas a vazão e a obstrução dos condutos. Sob o cultivo do feijoeiro, foram avaliados os efeitos dos drenos torpedo e de "camas" na drenagem e de cobertura morta (palha de arroz na retenção de água do solo. Os resultados indicaram que os drenos torpedo foram mais eficientes se construídos com solo menos úmido, porém sua longevidade foi menor que um ano. Sob o feijoeiro, os drenos torpedo e cobertura morta mantiveram o lençol freático mais profundo e o solo com menor tensão de umidade, mas esses efeitos ocorreram abaixo da zona radicular (15 cm, resultando em baixa produtividade.

  6. Recurrence of superficial vein thrombosis in patients with varicose veins.

    Science.gov (United States)

    Karathanos, Christos; Spanos, Konstantinos; Saleptsis, Vassileios; Tsezou, Aspasia; Kyriakou, Despina; Giannoukas, Athanasios D

    2016-08-01

    To investigate which factors other than history of superficial vein thrombosis (SVT) are associated with recurrent spontaneous SVT episodes in patients with varicose veins (VVs). Patients with a history of spontaneous SVT and VVs were followed up for a mean period of 55 months. Demographics, comorbidities, and thrombophilia screening test were analyzed. Patients were grouped according to the clinical-etiology-anatomy-pathophysiology classification. A multiple logistic regression analysis with the forward likelihood ratio method was undertaken. Thirteen patients out of 97 had a recurrence SVT episode during the follow-up period. All those patients were identified to have a thrombophilia defect. Protein C and S, antithrombin, and plasminogen deficiencies were more frequently present in patients without recurrence. Gene mutations were present in 38% in the nonrecurrence group and 77% in the recurrence group. After logistic regression analysis, patients with dislipidemia and mutation in prothrombin G20210A (FII) had an increased risk for recurrence by 5.4-fold and 4.6-fold, respectively. No deep vein thrombosis or pulmonary embolism occurred. Dislipidemia and gene mutations of F II are associated with SVT recurrence in patients with VVs. A selection of patients may benefit from anticoagulation in the short term and from VVs intervention in the long term. © The Author(s) 2015.

  7. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  8. Continuous measurements of in-bore projectile velocity

    International Nuclear Information System (INIS)

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.

    1989-01-01

    The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed

  9. Development of an optimal velocity selection method with velocity obstacle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Geuk; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

    2015-08-15

    The Velocity obstacle (VO) method is one of the most well-known methods for local path planning, allowing consideration of dynamic obstacles and unexpected obstacles. Typical VO methods separate a velocity map into a collision area and a collision-free area. A robot can avoid collisions by selecting its velocity from within the collision-free area. However, if there are numerous obstacles near a robot, the robot will have very few velocity candidates. In this paper, a method for choosing optimal velocity components using the concept of pass-time and vertical clearance is proposed for the efficient movement of a robot. The pass-time is the time required for a robot to pass by an obstacle. By generating a latticized available velocity map for a robot, each velocity component can be evaluated using a cost function that considers the pass-time and other aspects. From the output of the cost function, even a velocity component that will cause a collision in the future can be chosen as a final velocity if the pass-time is sufficiently long enough.

  10. Analyses of superficial and depth doses in intraoral radiology

    Energy Technology Data Exchange (ETDEWEB)

    Silva Santos de Oliveira, C.; Morais, R.P. de; Nascimento Souza, D. do [Universidade Federal de Sergipe - CCET - Dept. de Fisica, Sao Cristovao, SE (Brazil)

    2006-07-01

    In this work dosimetric analysis using thermoluminescence technique to study the beams characteristics of x-rays employed in dental radiology has been carried out. The obtained results with CaSO{sub 4}:Dy thermoluminescent dosimeters (TLD) were compared to the doses obtained with parallel-plates ionization chamber. Dosimetric evaluations were also done using radiographic films of large dimensions. The x-rays equipments analyzed were installed in the radiological services of Odontology Department of Sergipe Federal University (U.F.S.). Depending on the anatomical region to be examined the proper exposure time was select, for a fix voltage of 70 kV. The results with TLD and ionization chamber have been determined to female and male individuals. The intraoral regions analysed were the peri apical of the incisors, molar and pre-molar teeth and the occlusive region. These regions were simulated using acrylic plates absorbers installed on the film packet holder. The evaluation of the depth doses in the intraoral tissue was obtained using different acrylic plate thickness. The air kerma values have been evaluated with the ionization chamber located in the dental cone exit of the x-rays equipments. The integrated areas of the thermoluminescent glow curves showed coherent values when compared to the ones obtained with the ionization chamber and both methods presented a linear dependence with the exposition time. The analyses with films have allowed the evaluation of the beam scattering in the simulator apparatus. The studies had proven that the analysis of superficial dose and in depth used in dental radiology can be carried with thermoluminescent dosimeters. (authors)

  11. Teledetection applied to the superficial oceanography phenomena study

    International Nuclear Information System (INIS)

    Melo, Jeimmy

    2002-01-01

    The present document is consider the physical and biological variables important part in the integration of the climatic system, like improvement to the knowledge of the present marine processes in the Colombian marine areas by means of the advantage of the technological resources available at the present time for the obtaining of information in real time of physical and biological processes, agreed to the constitutional mandate of sustainable development. The images of color of the ocean provided by located remote sensors in the satellites allow considering primary the organic productivity of a synoptic way, in great areas. This is of great importance to more effectively support the rational handling of the fishing resources and to make a contribution on the paper of the ocean in the global climatic change. The marine phytoplankton can significantly alter to the carbon interchange in interactions ocean-atmosphere. The marine photosynthesis reduces the partial pressure of superficial water CO 2 , with the result of which a portion of organic carbon just formed (new productivity) sinks outside the afotica zone. The previous thing induces a net effect of carbon flow from the atmosphere to the ocean. One of the potential applications of the use of the images of satellite of color of the ocean is the calculation of the chlorophyll concentration and its relation with the sobreexperience of larvae of fish of commercial interest. Different types from developed mathematical models for concerning oceanic waters in the accomplishment of estimations of primary productivity with base in color images of the ocean exist mainly - time out - for that reason, the necessity of develop model similar for the calculation of the productivity primary of the phytoplankton of the Colombian marine area

  12. Analyses of superficial and depth doses in intraoral radiology

    International Nuclear Information System (INIS)

    Silva Santos de Oliveira, C.; Morais, R.P. de; Nascimento Souza, D. do

    2006-01-01

    In this work dosimetric analysis using thermoluminescence technique to study the beams characteristics of x-rays employed in dental radiology has been carried out. The obtained results with CaSO 4 :Dy thermoluminescent dosimeters (TLD) were compared to the doses obtained with parallel-plates ionization chamber. Dosimetric evaluations were also done using radiographic films of large dimensions. The x-rays equipments analyzed were installed in the radiological services of Odontology Department of Sergipe Federal University (U.F.S.). Depending on the anatomical region to be examined the proper exposure time was select, for a fix voltage of 70 kV. The results with TLD and ionization chamber have been determined to female and male individuals. The intraoral regions analysed were the peri apical of the incisors, molar and pre-molar teeth and the occlusive region. These regions were simulated using acrylic plates absorbers installed on the film packet holder. The evaluation of the depth doses in the intraoral tissue was obtained using different acrylic plate thickness. The air kerma values have been evaluated with the ionization chamber located in the dental cone exit of the x-rays equipments. The integrated areas of the thermoluminescent glow curves showed coherent values when compared to the ones obtained with the ionization chamber and both methods presented a linear dependence with the exposition time. The analyses with films have allowed the evaluation of the beam scattering in the simulator apparatus. The studies had proven that the analysis of superficial dose and in depth used in dental radiology can be carried with thermoluminescent dosimeters. (authors)

  13. Terbinafine-loaded wound dressing for chronic superficial fungal infections.

    Science.gov (United States)

    Paskiabi, Farnoush Asghari; Bonakdar, Shahin; Shokrgozar, Mohammad Ali; Imani, Mohammad; Jahanshiri, Zahra; Shams-Ghahfarokhi, Masoomeh; Razzaghi-Abyaneh, Mehdi

    2017-04-01

    In spite of developing new drugs and modern formulations, the treatments of chronic fungal infections are still challenging. Fibrous wound dressings are new suggestions for the treatment of chronic superficial infections. In the present study, we formulated an antifungal agent, terbinafine hydrochloride (TFH), which is a hydrophobic drug, in wound dressings prepared by electrospun polycaprolactone, polycaprolactone/gelatin (50:50 w/w) and gelatin. To obtain more water-stable meshes, the preparations were treated by glutaraldehyde and their properties were determined before and after treatment. The morphology of fibrous meshes was observed by scanning electron microscopy. Drug loading efficiency and release rate were measured by high performance liquid chromatography (HPLC) and the release rate was monitored for 144h. Antifungal tests were performed on Trichophyton mentagrophytes, Aspergillus fumigatus and Candida albicans cultured on Muller-Hinton agar. The toxicity of the meshes was measured after 24h and 14days by MTT assay. Terbinafine loading of polycaprolactone/gelatin (50:50) was 100% and it released the highest amount of TFH too. In antifungal tests, all samples were able to hinderT. mentagrophytes and A. fumigatus but not C. albicans growth among them, polycaprolactone fibers made the largest inhibition zone. In MTT assay, none of prepared samples showed toxicity against L929 cells. Teken together, the prepared TFH-loaded PCL/gelatin electrospun meshes were able to release TFH slowly and in a steady state in time. With respect to no obvious cytotoxicity in MTT assay and stong antifungal activity toward T. mentagrophytesin vitro, these TFH-based meshes could be considered as potential candidates in clinical application as wound dressing for treatment of chronic dermatophytosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. HDR brachytherapy for superficial non-melanoma skin cancers

    International Nuclear Information System (INIS)

    Gauden, Ruth; Pracy, Martin; Avery, Anne-Marie; Hodgetts, Ian; Gauden, Stan

    2013-01-01

    Our initial experience using recommended high dose per fraction skin brachytherapy (BT) treatment schedules, resulted in poor cosmesis. This study aimed to assess in a prospective group of patients the use of Leipzig surface applicators for High Dose Rate (HDR) brachytherapy, for the treatment of small non-melanoma skin cancers (NMSC) using a protracted treatment schedule. Treatment was delivered by HDR brachytherapy with Leipzig applicators. 36Gy, prescribed to between 3 to 4mm, was given in daily 3Gy fractions. Acute skin toxicity was evaluated weekly during irradiation using the Radiation Therapy Oncology Group criteria. Local response, late skin effects and cosmetic results were monitored at periodic intervals after treatment completion. From March 2002, 200 patients with 236 lesions were treated. Median follow-up was 66 months (range 25–121 months). A total of 162 lesions were macroscopic, while in 74 cases, BT was given after resection because of positive microscopic margins. There were 121 lesions that were basal cell carcinomas, and 115 were squamous cell carcinomas. Lesions were located on the head and neck (198), the extremities (26) and trunk (12). Local control was 232/236 (98%). Four patients required further surgery to treat recurrence. Grade 1 acute skin toxicity was detected in 168 treated lesions (71%) and grade 2 in 81 (34%). Cosmesis was good or excellent in 208 cases (88%). Late skin hypopigmentation changes were observed in 13 cases (5.5%). Delivering 36Gy over 2 weeks to superficial NMSC using HDR brachytherapy is well tolerated and provides a high local control rate without significant toxicity.

  15. Anatomical and Electrophysiological Clustering of Superficial Medial Entorhinal Cortex Interneurons

    Science.gov (United States)

    2017-01-01

    Abstract Local GABAergic interneurons regulate the activity of spatially-modulated principal cells in the medial entorhinal cortex (MEC), mediating stellate-to-stellate connectivity and possibly enabling grid formation via recurrent inhibitory circuitry. Despite the important role interneurons seem to play in the MEC cortical circuit, the combination of low cell counts and functional diversity has made systematic electrophysiological studies of these neurons difficult. For these reasons, there remains a paucity of knowledge on the electrophysiological profiles of superficial MEC interneuron populations. Taking advantage of glutamic acid decarboxylase 2 (GAD2)-IRES-tdTomato and PV-tdTomato transgenic mice, we targeted GABAergic interneurons for whole-cell patch-clamp recordings and characterized their passive membrane features, basic input/output properties and action potential (AP) shape. These electrophysiologically characterized cells were then anatomically reconstructed, with emphasis on axonal projections and pial depth. K-means clustering of interneuron anatomical and electrophysiological data optimally classified a population of 106 interneurons into four distinct clusters. The first cluster is comprised of layer 2- and 3-projecting, slow-firing interneurons. The second cluster is comprised largely of PV+ fast-firing interneurons that project mainly to layers 2 and 3. The third cluster contains layer 1- and 2-projecting interneurons, and the fourth cluster is made up of layer 1-projecting horizontal interneurons. These results, among others, will provide greater understanding of the electrophysiological characteristics of MEC interneurons, help guide future in vivo studies, and may aid in uncovering the mechanism of grid field formation. PMID:29085901

  16. Use your eyes - metallographic versus superficial traces of the crafting of Bronze Age ornaments

    DEFF Research Database (Denmark)

    Nørgaard, Heide Wrobel

    and superficial archaeological examinations can be used to understand prehistoric craft. Furthermore, it will show that with an intensive knowledge about previous scientific investigations the superficial traces preserved can reveal a great amount of information and could talk for themselves. Taking as an example...... the early and middle Bronze Age bronze ornaments from North Germany, superficial traces of the metal crafting process, visible with the naked eye, will be compared with metallographic images. The aim of this presentation is to give an overview over the crafting traces everybody could see (with a bit...

  17. Unexpected diagnosis of superficial neurofibroma in a lesion with imaging features of a vascular malformation

    Energy Technology Data Exchange (ETDEWEB)

    O' Keefe, Patrick; Reid, Janet; Morrison, Stuart [Cleveland Clinic Foundation, Department of Radiology, Cleveland, OH (United States); Vidimos, Allison [Cleveland Clinic Foundation, Department of Dermatology, Cleveland, OH (United States); DiFiore, John [Cleveland Clinic Foundation, Department of Pediatric Surgery, Cleveland, OH (United States)

    2005-12-01

    Plexiform neurofibroma is a pathognomonic, often disabling feature of neurofibromatosis type I. Although the target-like appearance of deep plexiform neurofibroma on T2-weighted MRI has been well-described, a second superficial form of plexiform neurofibroma has differing imaging features. We report a 15-year-old boy who presented with multiple cutaneous lesions exhibiting clinical and imaging characteristics of a venolymphatic malformation. These lesions were histologically proved to represent superficial plexiform neurofibromas. We wish to emphasize the unique MR findings of superficial plexiform neurofibromas; these findings are different from the imaging characteristics of the deep form and can be confused with a low-flow vascular malformation. (orig.)

  18. Comportamiento a fatiga del acero sae 4140 usando alta rugosidad superficial y ambiente corrosivo

    OpenAIRE

    CEBALLOS, WILSON FERNANDO; GÓMEZ, ADOLFO LEÓN; CORONADO, JOHN JAIRO

    2010-01-01

    En este artículo se presenta el estudio del comportamiento a fatiga del acero SAE 4140 en condiciones diferentes: superficie pulida (acabado espejo), ambiente corrosivo (jugo de caña de azúcar), alta rugosidad superficial (superficie equivalente a la encontrada típicamente en los ejes de molino de caña) y una condición que involucra la combinación de las dos últimas. Las anteriores condiciones están presentes en los ejes de maza de molino de caña de azúcar durante el proceso de molienda. Se r...

  19. COMPORTAMIENTO A FATIGA DEL ACERO SAE 4140 USANDO ALTA RUGOSIDAD SUPERFICIAL Y AMBIENTE CORROSIVO

    OpenAIRE

    CEBALLOS, WILSON FERNANDO; GÓMEZ, ADOLFO LEÓN; CORONADO, JOHN JAIRO

    2010-01-01

    En este artículo se presenta el estudio del comportamiento a fatiga del acero SAE 4140 en condiciones diferentes: superficie pulida (acabado espejo), ambiente corrosivo (jugo de caña de azúcar), alta rugosidad superficial (superficie equivalente a la encontrada típicamente en los ejes de molino de caña) y una condición que involucra la combinación de las dos últimas. Las anteriores condiciones están presentes en los ejes de maza de molino de caña de azúcar durante el proceso de molienda. Se r...

  20. Development of a PI fuzzy-neural control of two freedom degrees, applied to the velocity control of a turbo-gas unit; Desarrollo de un control PI neurodifuso no lineal de dos grados de libertad, aplicado al control de velocidad de una unidad turbogas

    Energy Technology Data Exchange (ETDEWEB)

    Castelo C, Luis; Garduno R, Raul [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Marmol M, Enrique Q [Cento Nacional de Investigacion y Desarrollo Tecnologico (Cenidet), Cuernavaca, Morelos (Mexico)

    2005-07-01

    The Instituto de Investigaciones Electricas has developed and implemented control systems in power stations with turbo gas unit (TGU) and of combined cycle power plants in which it has been detected several necessities and opportunities of technological development. One of most important is the improvement of the strategies of velocity control, power and temperature of the TGU, in order to obtain a safer and profitable operation. Since these units demand a strict and greater number of control requirements, because they are characterized by operating at temperatures, pressures and velocities higher than those of another type of units. An alternative to improve the control strategies of the TGU is the use of other control structures and the use of control techniques with diffuse logic, which can surpass the disadvantages of the conventional control. Due to the former, the reliability requirements of the TGU to get on line without fault, when required, have remarkably increased. The frequent accomplishment of starts, synchronization, load takings and shut-downs in a successful way and in automatic form, strongly depend on the capacities of the control system. During the starting, the main task of the control system consists of accelerating to the turbo-generator from the turn-shaft velocity to the nominal velocity according to a predefined acceleration pattern. The velocity control generates the control actions to accelerate the turbo-generator in a safe way that avoids the occurrence of instabilities of the working fluid, vibration discharges and resonances, high temperatures and combustion instabilities, and in addition, in the minimum of time, with fuel saving and preserving the useful life of the turbo-generator. [Spanish] El Instituto de Investigaciones Electricas ha desarrollado e implantado sistemas de control en centrales con unidad turbo gas (UTG) y centrales de ciclo combinado en las que se ha detectado varias necesidades y oportunidades de desarrollo

  1. Control rod velocity limiter

    International Nuclear Information System (INIS)

    Cearley, J.E.; Carruth, J.C.; Dixon, R.C.; Spencer, S.S.; Zuloaga, J.A. Jr.

    1986-01-01

    This patent describes a velocity control arrangement for a reciprocable, vertically oriented control rod for use in a nuclear reactor in a fluid medium, the control rod including a drive hub secured to and extending from one end therefrom. The control device comprises: a toroidally shaped control member spaced from and coaxially positioned around the hub and secured thereto by a plurality of spaced radial webs thereby providing an annular passage for fluid intermediate the hub and the toroidal member spaced therefrom in coaxial position. The side of the control member toward the control rod has a smooth generally conical surface. The side of the control member away from the control rod is formed with a concave surface constituting a single annular groove. The device also comprises inner and outer annular vanes radially spaced from one another and spaced from the side of the control member away from the control rod and positioned coaxially around and spaced from the hub and secured thereto by spaced radial webs thereby providing an annular passage for fluid intermediate the hub and the vanes. The vanes are angled toward the control member, the outer edge of the inner vane being closer to the control member and the inner edge of the outer vane being closer to the control member. When the control rod moves in the fluid in the direction toward the drive hub the vanes direct a flow of fluid turbulence which provides greater resistance to movement of the control rod in the direction toward the drive hub than in the other direction

  2. Velocity Dispersions Across Bulge Types

    International Nuclear Information System (INIS)

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-01-01

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (σ*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  3. Measurement of thermal plasma jet temperature and velocity by laser light lineshape analysis

    International Nuclear Information System (INIS)

    Snyder, S.C.; Reynolds, L.D.

    1991-01-01

    Two important parameters of thermal plasma jets are kinetic or gas temperatures and flow velocity. Gas temperatures have been traditionally measured using emission spectroscopy, but this method depends on either the generally unrealistic assumption of the existence of local thermodynamic equilibrium (LTE) within the plasma, or the use of various non-LTE or partial LTE models to relate the intensity of the emission lines to the gas temperature. Plasma jet velocities have been measured using laser Doppler velocimetry on particles injected into the plasma. However, this method is intrusive and it is not known how well the particle velocities represent the gas velocity. Recently, plasma jet velocities have been measured from the Doppler shift of laser light scattered by the plasma. In this case, the Doppler shift was determined from the difference in the transmission profile of a high resolution monochromator between red shifted and blue shifted scattered light. A direct approach to measuring localized temperatures and velocities is afforded by high resolution scattered light lineshape measurements. The linewidth of laser light scattered by atoms and ions can be related to the kinetic temperature without LTE assumptions, while a shift in the peak position relative to the incident laser lineshape yields the gas velocity. We report in this paper work underway to measure gas temperatures and velocities in an argon thermal plasma jet using high resolution lineshape analysis of scattered laser light

  4. Valoración de la superficie del dializador en la hemodiafiltración on-line. Elección objetiva de la superficie del dializador

    Directory of Open Access Journals (Sweden)

    Francisco Maduell

    2015-05-01

    Conclusión: El incremento del 40% y el 80% de la superficie conlleva un aumento del volumen convectivo de un 6 y un 16% respectivamente, aunque se evidenció una reducción en su máximo rendimiento, mostrando mínimas diferencias tanto en el volumen convectivo como en la capacidad depurativa cuando el CUF era superior a 45 ml/h/mmHg. Es recomendable optimizar el rendimiento de los dializadores a la mínima superficie posible adecuando la prescripción de tratamiento.

  5. Determination of hydrogen cluster velocities and comparison with numerical calculations

    International Nuclear Information System (INIS)

    Täschner, A.; Köhler, E.; Ortjohann, H.-W.; Khoukaz, A.

    2013-01-01

    The use of powerful hydrogen cluster jet targets in storage ring experiments led to the need of precise data on the mean cluster velocity as function of the stagnation temperature and pressure for the determination of the volume density of the target beams. For this purpose a large data set of hydrogen cluster velocity distributions and mean velocities was measured at a high density hydrogen cluster jet target using a trumpet shaped nozzle. The measurements have been performed at pressures above and below the critical pressure and for a broad range of temperatures relevant for target operation, e.g., at storage ring experiments. The used experimental method is described which allows for the velocity measurement of single clusters using a time-of-flight technique. Since this method is rather time-consuming and these measurements are typically interfering negatively with storage ring experiments, a method for a precise calculation of these mean velocities was needed. For this, the determined mean cluster velocities are compared with model calculations based on an isentropic one-dimensional van der Waals gas. Based on the obtained data and the presented numerical calculations, a new method has been developed which allows to predict the mean cluster velocities with an accuracy of about 5%. For this two cut-off parameters defining positions inside the nozzle are introduced, which can be determined for a given nozzle by only two velocity measurements

  6. Development of vortex model with realistic axial velocity distribution

    International Nuclear Information System (INIS)

    Ito, Kei; Ezure, Toshiki; Ohshima, Hiroyuki

    2014-01-01

    A vortex is considered as one of significant phenomena which may cause gas entrainment (GE) and/or vortex cavitation in sodium-cooled fast reactors. In our past studies, the vortex is assumed to be approximated by the well-known Burgers vortex model. However, the Burgers vortex model has a simple but unreal assumption that the axial velocity component is horizontally constant, while in real the free surface vortex has the axial velocity distribution which shows large gradient in radial direction near the vortex center. In this study, a new vortex model with realistic axial velocity distribution is proposed. This model is derived from the steady axisymmetric Navier-Stokes equation as well as the Burgers vortex model, but the realistic axial velocity distribution in radial direction is considered, which is defined to be zero at the vortex center and to approach asymptotically to zero at infinity. As the verification, the new vortex model is applied to the evaluation of a simple vortex experiment, and shows good agreements with the experimental data in terms of the circumferential velocity distribution and the free surface shape. In addition, it is confirmed that the Burgers vortex model fails to calculate accurate velocity distribution with the assumption of uniform axial velocity. However, the calculation accuracy of the Burgers vortex model can be enhanced close to that of the new vortex model in consideration of the effective axial velocity which is calculated as the average value only in the vicinity of the vortex center. (author)

  7. Sodium Velocity Maps on Mercury

    Science.gov (United States)

    Potter, A. E.; Killen, R. M.

    2011-01-01

    The objective of the current work was to measure two-dimensional maps of sodium velocities on the Mercury surface and examine the maps for evidence of sources or sinks of sodium on the surface. The McMath-Pierce Solar Telescope and the Stellar Spectrograph were used to measure Mercury spectra that were sampled at 7 milliAngstrom intervals. Observations were made each day during the period October 5-9, 2010. The dawn terminator was in view during that time. The velocity shift of the centroid of the Mercury emission line was measured relative to the solar sodium Fraunhofer line corrected for radial velocity of the Earth. The difference between the observed and calculated velocity shift was taken to be the velocity vector of the sodium relative to Earth. For each position of the spectrograph slit, a line of velocities across the planet was measured. Then, the spectrograph slit was stepped over the surface of Mercury at 1 arc second intervals. The position of Mercury was stabilized by an adaptive optics system. The collection of lines were assembled into an images of surface reflection, sodium emission intensities, and Earthward velocities over the surface of Mercury. The velocity map shows patches of higher velocity in the southern hemisphere, suggesting the existence of sodium sources there. The peak earthward velocity occurs in the equatorial region, and extends to the terminator. Since this was a dawn terminator, this might be an indication of dawn evaporation of sodium. Leblanc et al. (2008) have published a velocity map that is similar.

  8. Physiological Laterality of Superficial Cerebral Veins on Susceptibility-Weighted Imaging.

    Science.gov (United States)

    Matsushima, Satoshi; Shimizu, Tetsuya; Gomi, Taku; Fukuda, Kunihiko

    The purpose of this study is to evaluate whether laterality of the superficial cerebral veins can be seen on susceptibility-weighted imaging (SWI) in patients with no intracranial lesions that affect venous visualization. We retrospectively evaluated 386 patients who underwent brain magnetic resonance imaging including SWI in our institute. Patients with a lesion with the potential to affect venous visualization on SWI were excluded. Two neuroradiologists visually evaluated the findings and scored the visualization of the superficial cerebral veins. Of the 386 patients, 315 (81.6%) showed no obvious laterality on venous visualization, 64 (16.6%) showed left-side dominant laterality, and 7 (1.8%) showed right-side dominant laterality. Left-side dominant physiological laterality exists in the visualization of the superficial cerebral veins on SWI. Therefore, when recognizing left-side dominant laterality of the superficial cerebral veins on SWI, the radiologist must also consider the possibility of physiological laterality.

  9. DETERMINATION OF SUPERFICIAL ABSORBED DOSE FROM EXTERNAL EXPOSURE OF WEAKLY PENETRATING RADIATIONS

    Institute of Scientific and Technical Information of China (English)

    陈丽姝

    1994-01-01

    The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported.The distributions of beta dose were measured by an extrapolation ionization chamber at definite depthes corresponding to some superficial organs and tissues such as the radiosensitive layer of the skin,cornea,sclera,anterior chamber and lens of eyeball.The ratios among superficial absorbed dose D(0.07) and average absorbed doses at the depthes 1,2,3,4,5 and 6mm are also obtained with Cross's methods.They can be used for confining the deterministic effects of some superficial tissues and organs such as the skin and the components of eyeball for weakly penetrating radiations.

  10. Effects of immobilization on thickness of superficial zone of articular cartilage of patella in rats

    Directory of Open Access Journals (Sweden)

    Khadija Iqbal

    2012-01-01

    Conclusion: Each segment of superficial zone behaves differentially on immobilization and remobilization. Perhaps a much longer duration of remobilization is required to reverse changes of immobilization in articular cartilage and plays a significant role in knee joint movements.

  11. Influence of fluid-mechanical characteristics of the system on the volumetric mass transfer coefficient and gas dispersion in three-phase system

    Directory of Open Access Journals (Sweden)

    Knežević Milena M.

    2014-01-01

    Full Text Available Distribution of gas bubbles and volumetric mass transfer coefficient, Kla, in a three phase system, with different types of solid particles at different operation conditions were studied in this paper. The ranges of superficial gas and liquid velocities used in this study were 0,03-0,09 m/s and 0-0,1 m/s, respectively. The three different types of solid particles were used as a bed in the column (glass dp=3 mm, dp=6 mm; ceramic dp=6 mm. The experiments were carried out in a 2D plexiglas column, 278 x 20,4 x 500 mm and in a cylindrical plexiglas column, with a diameter of 64 mm and a hight of 2000 mm. The Kla coefficient increased with gas and liquid velocities. Results showed that the volumetric mass transfer coefficient has a higher values in three phase system, with solid particles, compared with two phase system. The particles properties (diameter and density have a major impact on oxygen mass transfer in three phase systems.

  12. Galactic hail: the origin of the high-velocity cloud complex C

    NARCIS (Netherlands)

    Fraternali, F.; Marasco, A.; Armillotta, L.; Marinacci, F.

    High-velocity clouds consist of cold gas that appears to be raining down from the halo to the disc of the Milky Way. Over the past 50 years, two competing scenarios have attributed their origin either to gas accretion from outside the Galaxy or to circulation of gas from the Galactic disc powered by

  13. Terbinafine-loaded wound dressing for chronic superficial fungal infections

    International Nuclear Information System (INIS)

    Paskiabi, Farnoush Asghari; Bonakdar, Shahin; Shokrgozar, Mohammad Ali; Imani, Mohammad; Jahanshiri, Zahra; Shams-Ghahfarokhi, Masoomeh; Razzaghi-Abyaneh, Mehdi

    2017-01-01

    In spite of developing new drugs and modern formulations, the treatments of chronic fungal infections are still challenging. Fibrous wound dressings are new suggestions for the treatment of chronic superficial infections. In the present study, we formulated an antifungal agent, terbinafine hydrochloride (TFH), which is a hydrophobic drug, in wound dressings prepared by electrospun polycaprolactone, polycaprolactone/gelatin (50:50 w/w) and gelatin. To obtain more water-stable meshes, the preparations were treated by glutaraldehyde and their properties were determined before and after treatment. The morphology of fibrous meshes was observed by scanning electron microscopy. Drug loading efficiency and release rate were measured by high performance liquid chromatography (HPLC) and the release rate was monitored for 144 h. Antifungal tests were performed on Trichophyton mentagrophytes, Aspergillus fumigatus and Candida albicans cultured on Muller-Hinton agar. The toxicity of the meshes was measured after 24 h and 14 days by MTT assay. Terbinafine loading of polycaprolactone/gelatin (50:50) was 100% and it released the highest amount of TFH too. In antifungal tests, all samples were able to hinderT. mentagrophytes and A. fumigatus but not C. albicans growth among them, polycaprolactone fibers made the largest inhibition zone. In MTT assay, none of prepared samples showed toxicity against L929 cells. Teken together, the prepared TFH-loaded PCL/gelatin electrospun meshes were able to release TFH slowly and in a steady state in time. With respect to no obvious cytotoxicity in MTT assay and stong antifungal activity toward T. mentagrophytesin vitro, these TFH-based meshes could be considered as potential candidates in clinical application as wound dressing for treatment of chronic dermatophytosis. - Highlights: • Terbinafine (TFH)-loaded PCL/gelatin electrospun fibers were successfully fabricated. • TFH-loaded PCL/gelatin electrospun fibers showed a slow drug release

  14. Terbinafine-loaded wound dressing for chronic superficial fungal infections

    Energy Technology Data Exchange (ETDEWEB)

    Paskiabi, Farnoush Asghari [Department of Mycology, Pasteur Institute of Iran, Tehran 13164. Iran (Iran, Islamic Republic of); Microbiology Research Center, Pasteur Institute of Iran, Tehran 13164. Iran (Iran, Islamic Republic of); Bonakdar, Shahin; Shokrgozar, Mohammad Ali [National Cell Bank Department, Pasteur Institute of Iran, Tehran 13164 (Iran, Islamic Republic of); Imani, Mohammad [Department of Novel Drug Delivery Systems, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of); Jahanshiri, Zahra [Department of Mycology, Pasteur Institute of Iran, Tehran 13164. Iran (Iran, Islamic Republic of); Shams-Ghahfarokhi, Masoomeh [Department of Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Razzaghi-Abyaneh, Mehdi, E-mail: mrab442@yahoo.com [Department of Mycology, Pasteur Institute of Iran, Tehran 13164. Iran (Iran, Islamic Republic of); Microbiology Research Center, Pasteur Institute of Iran, Tehran 13164. Iran (Iran, Islamic Republic of)

    2017-04-01

    In spite of developing new drugs and modern formulations, the treatments of chronic fungal infections are still challenging. Fibrous wound dressings are new suggestions for the treatment of chronic superficial infections. In the present study, we formulated an antifungal agent, terbinafine hydrochloride (TFH), which is a hydrophobic drug, in wound dressings prepared by electrospun polycaprolactone, polycaprolactone/gelatin (50:50 w/w) and gelatin. To obtain more water-stable meshes, the preparations were treated by glutaraldehyde and their properties were determined before and after treatment. The morphology of fibrous meshes was observed by scanning electron microscopy. Drug loading efficiency and release rate were measured by high performance liquid chromatography (HPLC) and the release rate was monitored for 144 h. Antifungal tests were performed on Trichophyton mentagrophytes, Aspergillus fumigatus and Candida albicans cultured on Muller-Hinton agar. The toxicity of the meshes was measured after 24 h and 14 days by MTT assay. Terbinafine loading of polycaprolactone/gelatin (50:50) was 100% and it released the highest amount of TFH too. In antifungal tests, all samples were able to hinderT. mentagrophytes and A. fumigatus but not C. albicans growth among them, polycaprolactone fibers made the largest inhibition zone. In MTT assay, none of prepared samples showed toxicity against L929 cells. Teken together, the prepared TFH-loaded PCL/gelatin electrospun meshes were able to release TFH slowly and in a steady state in time. With respect to no obvious cytotoxicity in MTT assay and stong antifungal activity toward T. mentagrophytesin vitro, these TFH-based meshes could be considered as potential candidates in clinical application as wound dressing for treatment of chronic dermatophytosis. - Highlights: • Terbinafine (TFH)-loaded PCL/gelatin electrospun fibers were successfully fabricated. • TFH-loaded PCL/gelatin electrospun fibers showed a slow drug release

  15. Radiotherapy for superficial esophageal cancer of poor risk patients

    International Nuclear Information System (INIS)

    Kagami, Yoshikazu; Ikeda, Hiroshi; Murayama, Shigeyuki; Yamaguchi, Hajime; Tachimori, Yuji; Kato, Hoichi; Watanabe, Hiroshi; Tokuue, Kouichi; Sumi, Minako; Kawashima, Mitsuhiko; Imai, Atsushi; Nakayama, Shuji

    1997-01-01

    Purpose/Objective: The reported incidence of superficial esophageal cancer (SEC) has steadily increased in Japan as result of endoscopic examination has been become common. In Japan, treatment of SEC is endoscopical mucosal resection (EMR) for mucosal cancer or esophagectomy with 3 fields lymph nodes resection for submucosal cancer. Radiotherapy is little place for the management of SEC. Because of some reasons, we treated patients with SEC by radiotherapy alternative to surgery. Purpose of this report is to evaluate efficacy of radiotherapy for SEC. Methods and Materials: Between 1989 to 1996, eighteen patients with SEC were treated with radiotherapy at our hospital. Reasons of radiotherapy that was chosen as the primary methods of treatment were refusal of surgery in one patient, poor medical condition in 4 patients and double primary cancer in 13 patients (head and neck: 11, simultaneously: 11). No patients had indication of EMR. Diagnosis was made by endoscopy and radiography. Some patients were examined with endoscopic ultrasound. Two patients (11.1%) had tumor limited to the mucosa and 16 patients (88.9%) had tumor invaded the submucosa. Seven of these tumors (38.9%) were multicentric. All patients had squamous cell carcinoma. There were 17 male patients and one female patient. The age range was 49 years to 87 years with a median of 62 years. Stage of all patients was T1N0M0 according to UICC staging system. Ten patients underwent external radiotherapy (Ex) (50 Gy - 66 Gy) alone and 8 patients did both Ex and intracavitary radiotherapy (IC) (30-60 Gy of Ex with 5-15 Gy of IC). No patients received chemotherapy. Duration of follow-up was 6 months to 96 months with a median of 30 months. Results: The overall survival rate was 55.9% in 3-year and 14% in 5-year, and the cause-specific 5-year survival rate was 100%. Causes of death were malignant tumor other than esophageal cancer in 4 patients, intercurrent disease other than malignant tumor in 3 patients and no

  16. Interaction of mobile phones with superficial passive metallic implants

    International Nuclear Information System (INIS)

    Virtanen, H; Huttunen, J; Toropainen, A; Lappalainen, R

    2005-01-01

    The dosimetry of exposure to radiofrequency (RF) electromagnetic (EM) fields of mobile phones is generally based on the specific absorption rate (SAR, W kg -1 ), which is the electromagnetic energy absorbed in the tissues per unit mass and time. In this study, numerical methods and modelling were used to estimate the effect of a passive, metallic (conducting) superficial implant on a mobile phone EM field and especially its absorption in tissues in the near field. Two basic implant models were studied: metallic pins and rings in the surface layers of the human body near the mobile phone. The aim was to find out 'the worst case scenario' with respect to energy absorption by varying different parameters such as implant location, orientation, size and adjacent tissues. Modelling and electromagnetic field calculations were carried out using commercial SEMCAD software based on the FDTD (finite difference time domain) method. The mobile phone was a 900 MHz or 1800 MHz generic phone with a quarter wave monopole antenna. A cylindrical tissue phantom models different curved sections of the human body such as limbs or a head. All the parameters studied (implant size, orientation, location, adjacent tissues and signal frequency) had a major effect on the SAR distribution and in certain cases high local EM fields arose near the implant. The SAR values increased most when the implant was on the skin and had a resonance length or diameter, i.e. about a third of the wavelength in tissues. The local peak SAR values increased even by a factor of 400-700 due to a pin or a ring. These highest values were reached in a limited volume close to the implant surface in almost all the studied cases. In contrast, without the implant the highest SAR values were generally reached on the skin surface. Mass averaged SAR 1g and SAR 10g values increased due to the implant even by a factor of 3 and 2, respectively. However, at typical power levels of mobile phones the enhancement is unlikely to be

  17. A Novel Technique of Supra Superficial Musculoaponeurotic System Hyaluronic Acid Injection for Lower Face Lifting

    OpenAIRE

    Sahawatwong, Sinijchaya; Sirithanabadeekul, Punyaphat; Patanajareet, Vasiyapha; Wattanakrai, Penpun; Thanasarnaksorn, Wilai

    2016-01-01

    Background: Various methods attempting to correct sagging of the lower face focus mainly on manipulation of the superficial musculoaponeurotic System. Each technique has its own limitation. The authors propose a relatively simple, conservative method utilizing hyaluronic acid injection just above the superficial musculoaponeurotic System. Objective: To address a novel hyaluronic injection technique to lift the lower face. Methods: Details of the injection techniques are described. The Positio...

  18. Clinicomycological Characterization of Superficial Mycoses from a Tertiary Care Hospital in Nepal

    OpenAIRE

    Khadka, Sundar; Sherchand, Jeevan Bahadur; Pokharel, Dinesh Binod; Pokhrel, Bharat Mani; Mishra, Shyam Kumar; Dhital, Subhash; Rijal, Basista

    2016-01-01

    Background. Superficial mycosis is a common fungal infection worldwide, mainly caused by dermatophytes. However, the prevalence of species varies geographically. In addition, fungal treatment is best guided according to species isolated. This study was carried out to determine the clinical as well as mycological profile of superficial mycoses in a tertiary care hospital, Nepal. Methods. This was a prospective case-control laboratory based study conducted over a period of six months from Janua...

  19. Emotional words can be embodied or disembodied: the role of superficial vs. deep types of processing

    OpenAIRE

    Abbassi, Ensie; Blanchette, Isabelle; Ansaldo, Ana I.; Ghassemzadeh, Habib; Joanette, Yves

    2015-01-01

    Emotional words are processed rapidly and automatically in the left hemisphere (LH) and slowly, with the involvement of attention, in the right hemisphere (RH). This review aims to find the reason for this difference and suggests that emotional words can be processed superficially or deeply due to the involvement of the linguistic and imagery systems, respectively. During superficial processing, emotional words likely make connections only with semantically associated words in the LH. This pa...

  20. Topographical anatomy of superficial veins, cutaneous nerves, and arteries at venipuncture sites in the cubital fossa.

    Science.gov (United States)

    Mikuni, Yuko; Chiba, Shoji; Tonosaki, Yoshikazu

    2013-01-01

    We investigated correlations among the superficial veins, cutaneous nerves, arteries, and venous valves in 128 cadaveric arms in order to choose safe venipuncture sites in the cubital fossa. The running patterns of the superficial veins were classified into four types (I-IV) and two subtypes (a and b). In types I and II, the median cubital vein (MCV) was connected obliquely between the cephalic and basilic veins in an N-shape, while the median antebrachial vein (MAV) opened into the MCV in type I and into the basilic vein in type II. In type III, the MCV did not exist. In type IV, additional superficial veins above the cephalic and basilic veins were developed around the cubital fossa. In types Ib-IVb, the accessory cephalic vein was developed under the same conditions as seen in types Ia-IVa, respectively. The lateral cutaneous nerve of the forearm descended deeply along the cephalic vein in 124 cases (97 %), while the medial cutaneous nerve of the forearm descended superficially along the basilic vein in 94 (73 %). A superficial brachial artery was found in 27 cases (21 %) and passed deeply under the ulnar side of the MCV. A median superficial antebrachial artery was found in 1 case (1 %), which passed deeply under the ulnar side of the MCV and ran along the MAV. Venous valves were found at 239 points in 28 cases with superficial veins, with a single valve seen at 79 points (33 %) and double valves at 160 points (67 %). At the time of intravenous injection, caution is needed regarding the locations of cutaneous nerves, brachial and superficial brachial arteries, and venous valves. The area ranging from the middle segment of the MCV to the confluence between the MCV and cephalic vein appears to be a relatively safe venipuncture site.

  1. Superficial siderosis of the central nervous system due to brachial plexus injury: a case report

    International Nuclear Information System (INIS)

    Setogutti, Enio Tadashi; Cassuriaga, Jefferson; Valduga, Simone Gianella; Lorenzzoni, Pablo Longhi; Severgnini, Giancarlo Muraro; Feldman, Carlos Jader

    2005-01-01

    Superficial siderosis can be caused by hemosiderin deposition o the leptomeninges and subpial layers of the neuro-axis due to recurrent subarachnoid haemorrhage. Probable intrathecal bleeding sites must be investigated. In ut t 50% of the patients the bleeding source may be identified and the progression of the disease can be interrupted. In this study, the authors present a case of superficial siderosis of the central nervous system developed two decades after a traumatic lesion of the brachial plexus.(author)

  2. Introduction to vector velocity imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Udesen, Jesper; Hansen, Kristoffer Lindskov

    Current ultrasound scanners can only estimate the velocity along the ultrasound beam and this gives rise to the cos() factor on all velocity estimates. This is a major limitation as most vessels are close to perpendicular to the beam. Also the angle varies as a function of space and time making ...

  3. Vascular patterns of upper limb: an anatomical study with accent on superficial brachial artery

    Directory of Open Access Journals (Sweden)

    David Kachlik

    2011-02-01

    Full Text Available The aim of the study was to evaluate the terminal segmentation of the axillary artery and to present four cases of anomalous branching of the axillary artery, the superficial brachial artery (arteria brachialis superficialis, which is defined as the brachial artery that runs superficially to the median nerve. Totally, 130 cadaveric upper arms embalmed by classical formaldehyde technique from collections of the Department of Anatomy, Third Faculty of Medicine, Charles University in Prague, were macroscopically dissected with special focus on the branching arrangement of the axillary artery. The most distal part of the axillary artery (infrapectoral part terminated in four cases as a bifurcation into two terminal branches: the superficial brachial artery and profunda brachii artery, denominated according to their relation to the median nerve. The profunda brachii artery primarily gave rise to the main branches of the infrapectoral part of the axillary artery. The superficial brachial artery descended to the cubital fossa where it assumed the usual course of the brachial artery in two cases and in the other two cases its branches (the radial and ulnar arteries passed superficially to the flexors. The incidence of the superficial brachial artery in our study was 5% of cases. The reported incidence is a bit contradictory, from 0.12% to 25% of cases. The anatomical knowledge of the axillary region is of crucial importance for neurosurgeons and specialists using the radiodiagnostic techniques, particularly in cases involving traumatic injuries. The improved knowledge would allow more accurate diagnostic interpretations and surgical treatment.

  4. Accurate Recovery of H i Velocity Dispersion from Radio Interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Ianjamasimanana, R. [Max-Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Blok, W. J. G. de [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Heald, George H., E-mail: roger@mpia.de, E-mail: blok@astron.nl, E-mail: George.Heald@csiro.au [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV, Groningen (Netherlands)

    2017-05-01

    Gas velocity dispersion measures the amount of disordered motion of a rotating disk. Accurate estimates of this parameter are of the utmost importance because the parameter is directly linked to disk stability and star formation. A global measure of the gas velocity dispersion can be inferred from the width of the atomic hydrogen (H i) 21 cm line. We explore how several systematic effects involved in the production of H i cubes affect the estimate of H i velocity dispersion. We do so by comparing the H i velocity dispersion derived from different types of data cubes provided by The H i Nearby Galaxy Survey. We find that residual-scaled cubes best recover the H i velocity dispersion, independent of the weighting scheme used and for a large range of signal-to-noise ratio. For H i observations, where the dirty beam is substantially different from a Gaussian, the velocity dispersion values are overestimated unless the cubes are cleaned close to (e.g., ∼1.5 times) the noise level.

  5. 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.

  6. Recent TAURUS results on Hα velocities in M83

    International Nuclear Information System (INIS)

    Allen, R.J.; Atherton, P.D.; Oosterloo, T.A.

    1983-01-01

    Preliminary Hα observations with the TAURUS imaging spectrometer confirm a pattern of systematic radial motions in a section of spiral arm in M83. The velocity gradients are not consistent with those predicted for the neutral gas. Non-circular motions have also been discovered in the central regions of the galaxy. (Auth.)

  7. Recent progress in the joint velocity-scalar PDF method

    Science.gov (United States)

    Anand, M. S.

    1995-01-01

    This viewgraph presentation discusses joint velocity-scalar PDF method; turbulent combustion modeling issues for gas turbine combustors; PDF calculations for a recirculating flow; stochastic dissipation model; joint PDF calculations for swirling flows; spray calculations; reduced kinetics/manifold methods; parallel processing; and joint PDF focus areas.

  8. Diffraction imaging and velocity analysis using oriented velocity continuation

    KAUST Repository

    Decker, Luke

    2014-08-05

    We perform seismic diffraction imaging and velocity analysis by separating diffractions from specular reflections and decomposing them into slope components. We image slope components using extrapolation in migration velocity in time-space-slope coordinates. The extrapolation is described by a convection-type partial differential equation and implemented efficiently in the Fourier domain. Synthetic and field data experiments show that the proposed algorithm is able to detect accurate time-migration velocities by automatically measuring the flatness of events in dip-angle gathers.

  9. Radial velocity asymmetries from jets with variable velocity profiles

    International Nuclear Information System (INIS)

    Cerqueira, A. H.; Vasconcelos, M. J.; Velazquez, P. F.; Raga, A. C.; De Colle, F.

    2006-01-01

    We have computed a set of 3-D numerical simulations of radiatively cooling jets including variabilities in both the ejection direction (precession) and the jet velocity (intermittence), using the Yguazu-a code. In order to investigate the effects of jet rotation on the shape of the line profiles, we also introduce an initial toroidal rotation velocity profile. Since the Yguazu-a code includes an atomic/ionic network, we are able to compute the emission coefficients for several emission lines, and we generate line profiles for the Hα, [O I]λ6300, [S II]λ6716 and [N II]λ6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly similar for rotating and non-rotating jet models

  10. Fractals control in particle's velocity

    International Nuclear Information System (INIS)

    Zhang Yongping; Liu Shutang; Shen Shulan

    2009-01-01

    Julia set, a fractal set of the literature of nonlinear physics, has significance for the engineering applications. For example, the fractal structure characteristics of the generalized M-J set could visually reflect the change rule of particle's velocity. According to the real world requirement, the system need show various particle's velocity in some cases. Thus, the control of the nonlinear behavior, i.e., Julia set, has attracted broad attention. In this work, an auxiliary feedback control is introduced to effectively control the Julia set that visually reflects the change rule of particle's velocity. It satisfies the performance requirement of the real world problems.

  11. Southern high-velocity stars

    International Nuclear Information System (INIS)

    Augensen, H.J.; Buscombe, W.

    1978-01-01

    Using the model of the Galaxy presented by Eggen, Lynden-Bell and Sandage (1962), plane galactic orbits have been calculated for 800 southern high-velocity stars which possess parallax, proper motion, and radial velocity data. The stars with trigonometric parallaxes were selected from Buscombe and Morris (1958), supplemented by more recent spectroscopic data. Photometric parallaxes from infrared color indices were used for bright red giants studied by Eggen (1970), and for red dwarfs for which Rodgers and Eggen (1974) determined radial velocities. A color-color diagram based on published values of (U-B) and (B-V) for most of these stars is shown. (Auth.)

  12. Design of channel experiment equipment for measuring coolant velocity of innovative research reactor

    International Nuclear Information System (INIS)

    Muhammad Subekti; Endiah Puji Hastuti; Dedi Heriyanto

    2014-01-01

    The design of innovative high flux research reactor (RRI) requires high power so that the capability core cooling requires to be improved by designing the faster core coolant velocity near to the critical velocity limit. Hence, the critical coolant velocity as the one of the important parameter of the reactor safety shall be measured by special equipment to the velocity limit that may induce fuel element degradation. The research aims is to calculate theoretically the critical coolant velocity and to design the special experiment equipment namely EXNal for measuring the critical coolant velocity in fuel element subchannel of the RRI. EXNal design considers the critical velocity calculation result of 20.52 m/s to determine the variation of flow rate of 4.5-29.2 m 3 /h, in which the experiment could simulate the 1-4X standard coolant velocity of RSG-GAS as well as destructive test of RRI's fuel plate. (author)

  13. Evaluating optimal superficial limb perfusion at different angles using non-invasive micro-lightguide spectrophotometry.

    Science.gov (United States)

    Darmanin, Geraldine; Jaggard, Matthew; Hettiaratchy, Shehan; Nanchahal, Jagdeep; Jain, Abhilash

    2013-06-01

    It is common practice to elevate the limbs postoperatively to reduce oedema and hence optimise perfusion and facilitate rehabilitation. However, elevation may be counterproductive as it reduces the mean perfusion pressure. There are no clear data on the optimal position of the limbs even in normal subjects. The optimal position of limbs was investigated in 25 healthy subjects using a non-invasive micro-lightguide spectrophotometry system "O2C", which indirectly measures skin and superficial tissue perfusion through blood flow, oxygen saturation and relative haemoglobin concentration. We found a reduction in skin and superficial tissue blood flow of 17% (p=0.0001) on arm elevation (180° shoulder flexion) as compared to heart level and an increase in skin and superficial tissue blood flow of 25% (p=0.02) on forearm elevation of 45°. Lower limb skin and superficial tissue blood flow decreased by 15% (p=0.004) on elevation to 47 cm and by 70% on dependency (p=0.0001) compared to heart level. However, on elevation of the lower limb there was also a 28% reduction in superficial venous pooling (p=0.0001) compared to heart level. In the normal limb, the position for optimal superficial perfusion of the upper limb is with the arm placed at heart level and forearm at 45°. In the lower limb the optimal position for superficial perfusion would be at heart level. However, some degree of elevation may be useful if there is an element of venous congestion. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  14. Computations in the deep vs superficial layers of the cerebral cortex.

    Science.gov (United States)

    Rolls, Edmund T; Mills, W Patrick C

    2017-11-01

    A fundamental question is how the cerebral neocortex operates functionally, computationally. The cerebral neocortex with its superficial and deep layers and highly developed recurrent collateral systems that provide a basis for memory-related processing might perform somewhat different computations in the superficial and deep layers. Here we take into account the quantitative connectivity within and between laminae. Using integrate-and-fire neuronal network simulations that incorporate this connectivity, we first show that attractor networks implemented in the deep layers that are activated by the superficial layers could be partly independent in that the deep layers might have a different time course, which might because of adaptation be more transient and useful for outputs from the neocortex. In contrast the superficial layers could implement more prolonged firing, useful for slow learning and for short-term memory. Second, we show that a different type of computation could in principle be performed in the superficial and deep layers, by showing that the superficial layers could operate as a discrete attractor network useful for categorisation and feeding information forward up a cortical hierarchy, whereas the deep layers could operate as a continuous attractor network useful for providing a spatially and temporally smooth output to output systems in the brain. A key advance is that we draw attention to the functions of the recurrent collateral connections between cortical pyramidal cells, often omitted in canonical models of the neocortex, and address principles of operation of the neocortex by which the superficial and deep layers might be specialized for different types of attractor-related memory functions implemented by the recurrent collaterals. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Numerical simulation and experimental verification of gas flow through packed beds

    International Nuclear Information System (INIS)

    Natarajan, S.; Zhang, C.; Briens, C.

    2003-01-01

    This work is concerned with finding out an effective way of eliminating oxygen from a packed bed of monomer particles. This process finds application in industries involved in the manufacture of Nylon12. In the manufacture of the polymer Nylon12, the polymerization reaction is hindered by the presence of oxygen. Therefore, the main objective of this study is to get rid of the oxygen by injecting nitrogen to displace the oxygen from the voids in-between the monomer particles before they are introduced into the polymerization reactor. This work involves the numerical simulation and experimental verification of the flow in a packed bed. In addition, a parametric study is carried out for the parameters such as the number of injectors, the radial position of injectors, and the position of the injectors along the circumference of the packed bed to find out the best possible combination for effective elimination of the oxygen. Nitrogen does not interact with the monomer particles and hence there is no chemical reaction involved in this process. The nitrogen is introduced into the packed bed at a flow rate which will keep the superficial velocity well below the minimum fluidization velocity of the monomer particles. The packed bed will be modeled using a porous medium approach available in the commercial computational fluid dynamics (CFD) software FLUENT. The fluid flow inside the packed bed will be a multicomponent gas flow through a porous medium. The simulation results are validated by comparing with the experimental results. (author)

  16. Settling velocities in batch sedimentation

    International Nuclear Information System (INIS)

    Fricke, A.M.; Thompson, B.E.

    1982-10-01

    The sedimentation of mixtures containing one and two sizes of spherical particles (44 and 62 μm in diameter) was studied. Radioactive tracing with 57 Co was used to measure the settling velocities. The ratio of the settling velocity U of uniformly sized particles to the velocity predicted to Stokes' law U 0 was correlated to an expression of the form U/U 0 = epsilon/sup α/, where epsilon is the liquid volume fraction and α is an empirical constant, determined experimentally to be 4.85. No effect of viscosity on the ratio U/U 0 was observed as the viscosity of the liquid medium was varied from 1x10 -3 to 5x10 -3 Pa.s. The settling velocities of particles in a bimodal mixture were fit by the same correlation; the ratio U/U 0 was independent of the concentrations of different-sized particles

  17. Superficial corneal foreign body: laboratory and epidemiologic aspects Corpo estranho corneal superficial: aspectos laboratoriais e epidemiológicos

    Directory of Open Access Journals (Sweden)

    Ednajar Tavares Macedo Filho

    2005-12-01

    Full Text Available PURPOSE: To determine by bacterioscopy and culture the microorganisms carried by corneal foreign body and their sensitivity to antibiotics by antibiotic sensitivity test. METHODS: A prospective study was carried out and information was collected on 101 patients who presented with corneal foreign body at the São Paulo Hospital Eye Emergency Service. Prior to any treatment, a sample of the ipsilateral inferior conjunctival fornix and the foreign body were collected and immersed in thioglycolate broth. Samples were sown on solid culture media including blood, chocolate and Sabouraud agar. Bacterioscopic examination using Gram and Giemsa staining and sensitivity test were performed. Positive foreign body culture results were compared to ipsilateral conjunctival fornix culture to exclude possible normal flora growth. RESULTS: Approximately 92% of patients were males with a mean age of 35 years and in 62.4% (95% confidence interval: 52.2 - 71.8% had the right eye was affected. Foreign body positive cultures were achieved in 32.7% (95% confidence interval: 23.7 - 42.7% of the cases. The microorganisms isolated from the foreign body culture were identified as: Streptococcus, alpha-hemolytic (n=4, Staphylococcus aureus (n=4, Staphylococcus, coagulase-negative (n=4, Corynebacterium xerosis (n=3, unidentified Gram-positive bacillus (n=2, Moraxella sp (n=1, Serratia sp (n=1, Acynetobacter sp (n=1. The microbial sensitivity test showed that 95% of the cases were sensitive to chloramphenicol and 90% were sensitive to ciprofloxacin, these being antibiotics used in our routine service. CONCLUSION: Superficial corneal foreign body acts as important contaminant vector and the great majority of isolated bacteria were sensitive to the antibiotic prophylaxis used in the treatment.OBJETIVOS: Identificar por meio de cultura e bacterioscopia os microrganismos veiculados por corpo estranho corneal e sua sensibilidade aos antibióticos em teste de antibiograma. M

  18. Study on Droplet Size and Velocity Distributions of a Pressure Swirl Atomizer Based on the Maximum Entropy Formalism

    Directory of Open Access Journals (Sweden)

    Kai Yan

    2015-01-01

    Full Text Available A predictive model for droplet size and velocity distributions of a pressure swirl atomizer has been proposed based on the maximum entropy formalism (MEF. The constraint conditions of the MEF model include the conservation laws of mass, momentum, and energy. The effects of liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio on the droplet size and velocity distributions of a pressure swirl atomizer are investigated. Results show that model based on maximum entropy formalism works well to predict droplet size and velocity distributions under different spray conditions. Liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio have different effects on droplet size and velocity distributions of a pressure swirl atomizer.

  19. Influencia de la molienda en la energía superficial de fritas para esmaltes

    Directory of Open Access Journals (Sweden)

    Tamayo, A.

    2013-04-01

    Full Text Available In this work has been studied the influence of the milling process of two ceramic frits used in the ceramic tile industry. Both glass frits were of similar chemical composition changing SiO2 by 5% of B2O3 and both of them were water or dry milled. Glass frit surfaces were characterized by FT-IR, Karl-Fischer (K-F titration and Inverse Gas Chromatography at Infinite Dilution (IGC-ID. By K-F titration it was observed that water milled frits presented 28 and 26 OH groups for 100 A2 if they do not contain or contain boron, respectively. These surface changes are also observed by IGC-ID. Thus, the glass frit without boron and dry milled presented the highest dispersive surface energy (44 mJ.m-2 and the less acidic constant (0.13 kJ.mol-1. Both glass frits are amphoteric with acidic and base surface active sites, and that frit without boron presents the higher basicity. Milling process influences in the acid-base surface characteristics of both frits by increasing the basicity for the one without boron and increasing for the other one. This has been assigned to the different location of hydroxyl groups where the higher interaction is the one that does not contain boron and dry milled as K-F results.Se ha estudiado el proceso de molienda en dos fritas de la industria cerámica. Las dos fritas, de composiciones similares pero en una se ha sustituido parte de la sílice por 5% de óxido de boro, fueron molidas por vía seca o húmeda y se caracterizaron mediante FT-IR, valoración Karl-Fischer e IGC-ID. Mediante valoración se han determinado los contenidos en moléculas de agua e hidroxilos. El mayor contenido en hidroxilos lo posee la frita sin boro seguida de la de boro ambas molidas en húmedo, poseyendo 28 y 26 grupos OH por cada 100 A2, respectivamente. Estos resultados coinciden con IGC-ID, sin embargo es la frita sin boro molida en seco la de mayor energía superficial (44 mJ.m-2 y constante ácida (0.13 kJ.mol-1. Aunque las dos fritas tienen

  20. Online Wavelet Complementary velocity Estimator.

    Science.gov (United States)

    Righettini, Paolo; Strada, Roberto; KhademOlama, Ehsan; Valilou, Shirin

    2018-02-01

    In this paper, we have proposed a new online Wavelet Complementary velocity Estimator (WCE) over position and acceleration data gathered from an electro hydraulic servo shaking table. This is a batch estimator type that is based on the wavelet filter banks which extract the high and low resolution of data. The proposed complementary estimator combines these two resolutions of velocities which acquired from numerical differentiation and integration of the position and acceleration sensors by considering a fixed moving horizon window as input to wavelet filter. Because of using wavelet filters, it can be implemented in a parallel procedure. By this method the numerical velocity is estimated without having high noise of differentiators, integration drifting bias and with less delay which is suitable for active vibration control in high precision Mechatronics systems by Direct Velocity Feedback (DVF) methods. This method allows us to make velocity sensors with less mechanically moving parts which makes it suitable for fast miniature structures. We have compared this method with Kalman and Butterworth filters over stability, delay and benchmarked them by their long time velocity integration for getting back the initial position data. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Towards optical spectroscopy of the element nobelium (Z = 102) in a buffer gas cell. First on-line experiments on {sup 155}Yb at the velocity filter SHIP with a novel ion collection and atom re-evaporation method of high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Backe, H.; Kunz, P.; Lauth, W.; Dretzke, A.; Horn, R.; Kolb, T. [Mainz Univ., Institut fur Kernphysik (Germany); Laatiaoui, M.; Sewtz, M. [Munchen Ludwig-Maximilians-Univ., Dept. fur Physik, Garching (Germany); Ackermann, D.; Block, M.; Herfurth, F.; Hebberger, F.P.; Hofmann, S.; Mann, R. [Gesellschaft fur Schwerionenforschung, Darmstadt (Germany)

    2007-10-15

    For the investigation of the atomic level structure of heavy elements which can only be produced at on-line facilities such as GSI (Darmstadt, Germany), a novel experimental procedure has been developed. It is based on Radiation Detected Resonance Ionization Spectroscopy (RADRIS) and can be applied to elements like nobelium produced at rates of a few ions per second. Fusion reaction products are separated from the primary beam by the velocity filter SHIP at GSI, stopped in a buffer gas cell, collected on a tantalum filament and then re-evaporated as atoms. The ions produced by resonance ionization with tunable laser beams are detected via their characteristic alpha decay. First on-line experiments on alpha-active {sup 155}Yb, which is supposed to have an atomic level structure similar to nobelium, were performed. These test experiments focused on the optimization of the collection and re-evaporation process of the radioactive ions, the laser ionization efficiency and the detection via alpha decay. An overall efficiency for RADRIS of 0.8% with respect to the target production rate was measured. While further improvements of this efficiency are in progress it should already be sufficient for the search for atomic levels in nobelium. (authors)

  2. Towards optical spectroscopy of the element nobelium (Z = 102) in a buffer gas cell. First on-line experiments on 155Yb at the velocity filter SHIP with a novel ion collection and atom re-evaporation method of high efficiency

    International Nuclear Information System (INIS)

    Backe, H.; Kunz, P.; Lauth, W.; Dretzke, A.; Horn, R.; Kolb, T.; Laatiaoui, M.; Sewtz, M.; Ackermann, D.; Block, M.; Herfurth, F.; Hebberger, F.P.; Hofmann, S.; Mann, R.

    2007-01-01

    For the investigation of the atomic level structure of heavy elements which can only be produced at on-line facilities such as GSI (Darmstadt, Germany), a novel experimental procedure has been developed. It is based on Radiation Detected Resonance Ionization Spectroscopy (RADRIS) and can be applied to elements like nobelium produced at rates of a few ions per second. Fusion reaction products are separated from the primary beam by the velocity filter SHIP at GSI, stopped in a buffer gas cell, collected on a tantalum filament and then re-evaporated as atoms. The ions produced by resonance ionization with tunable laser beams are detected via their characteristic alpha decay. First on-line experiments on alpha-active 155 Yb, which is supposed to have an atomic level structure similar to nobelium, were performed. These test experiments focused on the optimization of the collection and re-evaporation process of the radioactive ions, the laser ionization efficiency and the detection via alpha decay. An overall efficiency for RADRIS of 0.8% with respect to the target production rate was measured. While further improvements of this efficiency are in progress it should already be sufficient for the search for atomic levels in nobelium. (authors)

  3. Clinicopahological features of superficial basaloid squamous cell carcinoma of the esophagus.

    Science.gov (United States)

    Oguma, J; Ozawa, S; Kazuno, A; Nitta, M; Ninomiya, Y; Tomita, S

    2017-12-01

    Basaloid squamous cell carcinoma (BSC) of the esophagus is classified as an epithelial malignant tumor and is a rare variant of squamous cell carcinoma (SCC). Most previous reports have suggested that advanced BSC has a poorer prognosis than typical SCC because of its high biological malignancy, but the biological activity of superficial BSC remains unclear. Twenty cases of superficial BSC, which underwent surgical resection in Tokai University Hospital between January 2004 and December 2013, were analyzed retrospectively. Among these cases, 19 cases with a T1 depth of invasion (BSC group) were compared with 180 cases of SCC that were resected during the same period and were pathologically diagnosed as T1 (SCC group). The frequency of lymph node metastasis in the T1 BSC group was significantly lower (2 patients, 11%) than that in the SCC group (84 patients, 47%) (P = 0.005). The frequency of lymphatic invasion in the BSC group was also lower (9 patients, 47%) than that in the SCC group (131 patients, 73%) (P = 0.021). The pathological type of the metastatic lymph node was BSC in all the superficial BSC cases with lymph node metastasis. This study demonstrated that lymph node metastasis was less likely to occur in cases with superficial BSC than in cases with superficial SCC. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Clinicomycological Characterization of Superficial Mycoses from a Tertiary Care Hospital in Nepal.

    Science.gov (United States)

    Khadka, Sundar; Sherchand, Jeevan Bahadur; Pokharel, Dinesh Binod; Pokhrel, Bharat Mani; Mishra, Shyam Kumar; Dhital, Subhash; Rijal, Basista

    2016-01-01

    Background . Superficial mycosis is a common fungal infection worldwide, mainly caused by dermatophytes. However, the prevalence of species varies geographically. In addition, fungal treatment is best guided according to species isolated. This study was carried out to determine the clinical as well as mycological profile of superficial mycoses in a tertiary care hospital, Nepal. Methods . This was a prospective case-control laboratory based study conducted over a period of six months from January to June 2014 at Tribhuvan University Teaching Hospital, Nepal. A total of 200 specimens were collected from the patients suspected of superficial mycoses. The specimens were macroscopically as well as microscopically examined. The growth was observed up to 4 weeks. Results. Out of total 200 specimens from the patients suspected of superficial mycoses, tinea corporis 50 (25%) was most common clinical types. KOH mount was positive in 89 (44.5%) and culture was positive in 111 (55.5%). Trichophyton mentagrophytes 44 (39.6%) was the most common isolate. Conclusions. The diagnostic yields of KOH mount and culture were found to be complementary to each other. Thus both the methods added with clinical findings are equally important to establish superficial mycosis.

  5. Clinicomycological Characterization of Superficial Mycoses from a Tertiary Care Hospital in Nepal

    Directory of Open Access Journals (Sweden)

    Sundar Khadka

    2016-01-01

    Full Text Available Background. Superficial mycosis is a common fungal infection worldwide, mainly caused by dermatophytes. However, the prevalence of species varies geographically. In addition, fungal treatment is best guided according to species isolated. This study was carried out to determine the clinical as well as mycological profile of superficial mycoses in a tertiary care hospital, Nepal. Methods. This was a prospective case-control laboratory based study conducted over a period of six months from January to June 2014 at Tribhuvan University Teaching Hospital, Nepal. A total of 200 specimens were collected from the patients suspected of superficial mycoses. The specimens were macroscopically as well as microscopically examined. The growth was observed up to 4 weeks. Results. Out of total 200 specimens from the patients suspected of superficial mycoses, tinea corporis 50 (25% was most common clinical types. KOH mount was positive in 89 (44.5% and culture was positive in 111 (55.5%. Trichophyton mentagrophytes 44 (39.6% was the most common isolate. Conclusions. The diagnostic yields of KOH mount and culture were found to be complementary to each other. Thus both the methods added with clinical findings are equally important to establish superficial mycosis.

  6. Gross anatomy of superficial fascia and future localised fat deposit areas of the abdomen in foetus

    Directory of Open Access Journals (Sweden)

    Pramod Kumar

    2013-01-01

    Full Text Available Background: The development and popularity of body contouring procedures such as liposuction and abdominoplasty has renewed interest in the anatomy of the superficial fascia and subcutaneous fat deposits of the abdomen. The study of anatomy of fascia and fetal adipose tissue was proposed as it may be of value in understanding the possible programing of prevention of obesity. Objectives: The present study was undertaken to understand the gross anatomy of superficial fascia of abdomen and to study the gross anatomy of future localized fat deposits (LFDs area of abdomen in fetus. Materials and Methods: Four fetus (two male & two female of four month of intrauterine life were dissected. Attachments & layers of superficial fascia and future subcutaneous fat deposit area of upper and lower abdomen were noted. Results: Superficial fascia of the abdomen was multi layered in mid line and number of layers reduced laterally as in adult. The future abdominal LFD (localized fat deposits area in fetus shows brownish-white blubbary tissue without well-defined adult fat lobules. Conclusion: The attachment and gross anatomy of superficial fascia of the fetus was similar to that in adults. The future LFD areas showed brownish white blubbary tissue with ill-defined fat lobules.

  7. Shock velocity in weakly ionized nitrogen, air, and argon

    International Nuclear Information System (INIS)

    Siefert, Nicholas S.

    2007-01-01

    The goal of this research was to determine the principal mechanism(s) for the shock velocity increase in weakly ionized gases. This paper reports experimental data on the propagation of spark-generated shock waves (1< Mach<3) into weakly ionized nitrogen, air, and argon glow discharges (1 < p<20 Torr). In order to distinguish between effects due solely to the presence of electrons and effects due to heating of the background gas via elastic collisions with electrons, the weakly ionized discharge was pulsed on/off. Laser deflection methods determined the shock velocity, and the electron number density was collected using a microwave hairpin resonator. In the afterglow of nitrogen, air, and argon discharges, the shock velocity first decreased, not at the characteristic time for electrons to diffuse to the walls, but rather at the characteristic time for the centerline gas temperature to equilibrate with the wall temperature. These data support the conclusion that the principal mechanism for the increase in shock velocity in weakly ionized gases is thermal heating of the neutral gas species via elastic collisions with electrons

  8. One-loop fluctuation-dissipation formula for bubble-wall velocity

    International Nuclear Information System (INIS)

    Arnold, P.

    1993-01-01

    The limiting bubble wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. It is demonstrated that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas limit

  9. One-loop fluctuation-dissipation formula for bubble-wall velocity

    International Nuclear Information System (INIS)

    Arnold, P.

    1993-01-01

    The limiting bubble-wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. I demonstrate that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas (''thin-wall'') limit

  10. Laminar burning velocities of acetone in air at room and elevated temperatures

    NARCIS (Netherlands)

    Nilsson, E.J.K.; Goey, de L.P.H.; Konnov, A.

    2013-01-01

    Laminar burning velocities of acetone + air mixtures at initial gas mixture temperatures of 298, 318, 338 and 358 K are reported. Non-stretched flames were stabilized on a perforated plate burner at 1 atm, and laminar burning velocities were determined using the heat flux method, at conditions where

  11. Attenuation and velocity dispersion in the exploration seismic frequency band

    Science.gov (United States)

    Sun, Langqiu

    In an anelastic medium, seismic waves are distorted by attenuation and velocity dispersion, which depend on petrophysical properties of reservoir rocks. The effective attenuation and velocity dispersion is a combination of intrinsic attenuation and apparent attenuation due to scattering, transmission response, and data acquisition system. Velocity dispersion is usually neglected in seismic data processing partly because of insufficient observations in the exploration seismic frequency band. This thesis investigates the methods of measuring velocity dispersion in the exploration seismic frequency band and interprets the velocity dispersion data in terms of petrophysical properties. Broadband, uncorrelated vibrator data are suitable for measuring velocity dispersion in the exploration seismic frequency band, and a broad bandwidth optimizes the observability of velocity dispersion. Four methods of measuring velocity dispersion in uncorrelated vibrator VSP data are investigated, which are the sliding window crosscorrelation (SWCC) method, the instantaneous phase method, the spectral decomposition method, and the cross spectrum method. Among them, the SWCC method is a new method and has satisfactory robustness, accuracy, and efficiency. Using the SWCC method, velocity dispersion is measured in the uncorrelated vibrator VSP data from three areas with different geological settings, i.e., Mallik gas hydrate zone, McArthur River uranium mines, and Outokumpu crystalline rocks. The observed velocity dispersion is fitted to a straight line with respect to log frequency for a constant (frequency-independent) Q value. This provides an alternative method for calculating Q. A constant Q value does not directly link to petrophysical properties. A modeling study is implemented for the Mallik and McArthur River data to interpret the velocity dispersion observations in terms of petrophysical properties. The detailed multi-parameter petrophysical reservoir models are built according to

  12. Studio della superficie degli impianti dentali in titanio: La nanotecnologia nella valutazione delle nuove superfici implantari in rapporto all'osteointegrazione dei mascellari

    OpenAIRE

    Ricci, Emanuele

    2015-01-01

    Il presente lavoro parte dalla descrizione dei processi di rimodellamento osseo mascellare a seguito della perdita di elementi dentari e la successiva riabilitazione mediante impianto dentale osteointegrato. Approfondiremo proprio i complessi aspetti dell’osteointegrazione su superfici implantari in titanio sia a livello micro che macroscopico. Nel campo dell’implantologia, infatti, il titanio risulta essere il materiale maggiormente impiegato in virtù della sua eccellente biocompatibilità...

  13. Electron drift velocity in argon-methane mixture

    International Nuclear Information System (INIS)

    Hakeem, N.El; Mathieson, E.

    1978-01-01

    Described are the results of a series of measurements of electron drift velocity taken with samples of chemically pure grade gas mixture of Ar-10% CH 4 (N 2 2 2 2 O<2 ppm). The measured drift velocity is plotted as a function of the ratio of electric field to pressure in the range from 0.05 to 0.8 V/cmxtorr. The measurements are reproducible only to within 4%. The results of numerical calculations employing the well-established argon elastic and methane elastic and inelastic cross sections are also included. The disagreement from the present experimental results, and from those obtained elsewhere, is rather puzzling

  14. Gas-liquid flow around an obstacle in a vertical pipe

    International Nuclear Information System (INIS)

    Prasser, Horst-Michael; Beyer, Matthias; Frank, Thomas; Al Issa, Suleiman; Carl, Helmar; Pietruske, Heiko; Schuetz, Peter

    2008-01-01

    This paper presents a novel technique to study the two-phase flow field around an asymmetric obstruction in a vertical pipe with a nominal diameter of DN200. Main feature of the experiments is the shifting of a half-moon shaped diaphragm causing the obstruction along the axis of the pipe. In this way, the 3D void field is scanned with a stationary wire-mesh sensor that supplies data with a spatial resolution of 3 mm over the cross-section and a measuring frequency of 2.5 kHz. Besides the measurement of time-averaged void fraction fields and bubble-size distributions, novel data evaluation methods were developed to extract estimated liquid velocity profiles as well as lateral components of bubble velocities from the wire-mesh sensor data. The combination of void fraction fields and velocity profiles offer the opportunity to analyse a two-phase flow in a geometry that owns a series of features characteristic for complex components of power and chemical plant equipment. Such characteristics are sharp edges with flow separation, recirculation areas, jet formation, stagnation points and curved stream-lines. The tests were performed with an air-water flow at nearly ambient conditions and with a saturated steam-water mixture at 6.5 MPa. The superficial velocities of liquid and gas or, respectively, vapour were varied in a wide range. The flow structure upstream and downstream of the obstacle is characterized in detail. Bubble size dependent effects of bubble accumulation and migration are discussed on basis of void-fraction profiles decomposed into bubble-size classes. A pronounced influence of the fluid parameters was found in the behaviour of bubbles at the boundary of the jet coming from the non-obstructed part of the cross-section. In case of an air-water flow, bubbles are restrained from entering the jet, a phenomenon which was not observed in high-pressure steam-water flow. A detailed uncertainty analyse of the velocity assessments finishes the presented paper. A

  15. Gas Kinematics in GRB Host Galaxies

    DEFF Research Database (Denmark)

    Arabsalmani, Maryam

    towards a relation between gas kinematics and mass. This also provides information on how the metallicities measured from absorption and emission methods differ from each other. Finally, in a direct study I show that gas velocity widths in both phases can be used as a proxy of stellar mass...... that their interstellar media imprint on the GRBs’ spectra. Hence they are invaluable tools to probe the star formation history of the Universe back to the earliest cosmic epochs. To this end, it is essential to achieve a comprehensive picture of the interplay between star formation and its fuel, neutral gas, in GRB...... simultaneously with a high velocity resolution. For the large GRB sample, I find the spatially averaged velocity to correlate with metallicity in both gas phases. This is an indicator of a mass-metallicity relation. Moreover, the velocity widths in the two gas phases correlate with each other which too points...

  16. Superficial x-ray in-vivo dosimetry with MOSFET detectors

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: This note investigates in-vivo dosimetry using a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for radiotherapy treatment at superficial and orthovoltage x-ray energies. This was performed within one fraction of the patient's treatment. Standard measurements along with energy response of the detector are given. Results showed that the MOSFET measurements in-vivo agreed with calculated results on average within ± 5.6% over all superficial and orthovoltage energies. These variations were slightly larger than TLD results with variations between measured and calculated results being ± 5.0% for the same patient measurements. The MOSFET device provides adequate in-vivo dosimetry for superficial and orthovoltage energy treatments with the accuracy of the measurements seeming to be relatively on par with TLD in our case. The MOSFET does have the advantage of returning a relatively immediate dosimetric result after irradiation. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  17. Castelli di carta. La piega per la costruzione di superfici articolate

    Directory of Open Access Journals (Sweden)

    Andrea Casale

    2012-06-01

    Full Text Available L’antica arte del piegare la carta, l’Origami, sta vivendo un rinnovato interesse che coinvolge molti aspetti della ricerca.  Con il termine origami, si intende lo studio del modo di piegare il foglio di carta per imporgli una specifica forma.  La superficie tassellata per mezzo di specifiche pieghe, si propone come un nuovo soggetto di studio: la superficie piegata articolata. La forma congiunta al movimento, assume un particolare interesse nella contemporanea ricerca geometrica e architettonica. Il panorama contemporaneo, propone opere di architettura “responsiva”, capaci di modificare le proprie caratteristiche per adeguarsi a nuove condizioni. La superficie piegata articolata sembra particolarmente adatta a descrivere questo modo d’intendere l’architettura, reagendo a diverse volontà e di conseguenza modificando la propria conformazione attraverso un attento controllo progettuale della forma.

  18. Neurothekeoma palpebrae in association with multiple superficial angiomyxomas: Tegumental Angiomyxoma- Neurothekeoma syndrome (TAN syndrome

    Directory of Open Access Journals (Sweden)

    Tan Aik Kah

    2011-09-01

    Full Text Available We report a case of 10-year-old Indian girl with history of multiple superficial angiomyxoma, presented with three months history of painless right upper lid swelling. There were no visual dysfunctions. Previously, the patient had multiple superficial angiomyxoma (left pinna, left upper cheek, left upper limb, chest, right axilla, hard palate and epidermal cyst (chin. The histopathological specimens were negative to S-100 protein antibody. Systemic review and family history was unremarkable. Excision biopsy and upper lid reconstruction were performed. Intraoperatively the tumor was multilobulated, firm, well encapsulated and did not invade the underlying tarsal plate. Histopathological features of the upperlid tumor were consistent with nerves sheath myxoma (neurothekeoma. To the best of the authors’ knowledge, this is the first reported case of neurothekeoma in association with multiple superficial angiomyxoma.

  19. Neurothekeoma palpebrae in association with multiple superficial angiomyxomas: Tegumental Angiomyxoma-Neurothekeoma syndrome (TAN syndrome).

    Science.gov (United States)

    Kah, Tan Aik; Yong, Ku Chui; Annuar, Faridah Hanom

    2011-07-01

    We report a case of 10-year-old Indian girl with history of multiple superficial angiomyxoma, presented with three months history of painless right upper lid swelling. There were no visual dysfunctions. Previously, the patient had multiple superficial angiomyxoma (left pinna, left upper cheek, left upper limb, chest, right axilla, hard palate) and epidermal cyst (chin). The histopathological specimens were negative to S-100 protein antibody. Systemic review and family history was unremarkable. Excision biopsy and upper lid reconstruction were performed. Intraoperatively the tumor was multilobulated, firm, well encapsulated and did not invade the underlying tarsal plate. Histopathological features of the upperlid tumor were consistent with nerves sheath myxoma (neurothekeoma). To the best of the authors' knowledge, this is the first reported case of neurothekeoma in association with multiple superficial angiomyxoma.

  20. Superficie Específica y Estado Vital de la Materia

    OpenAIRE

    J. Hernando Ordoñez

    1992-01-01

    Se propone reemplazar el término de materia viva por el de estado vital de la materia por considerarlo adecuado, pues la materia es la misma, lo que cambia es su estado. Se estudia la relación entre la superficie específica y el estado vital de la materia. Constante del estado vital y el valor crítico de la superficie específica. Qué es la fuerza de inducción vital? Diferenciación funcional de las células. Cómo regula la unidad biológica su superficie específica? La materia que piens...

  1. "A Tale of Two Planes": Deep Versus Superficial Serratus Plane Block for Postmastectomy Pain Syndrome.

    Science.gov (United States)

    Piracha, Mohammad M; Thorp, Stephen L; Puttanniah, Vinay; Gulati, Amitabh

    Postmastectomy pain syndrome (PMPS) is a significant burden for breast cancer survivors. Although multiple therapies have been described, an evolving field of serratus anterior plane blocks has been described in this population. We describe the addition of the deep serratus anterior plane block (DSPB) for PMPS. Four patients with history of PMPS underwent DSPB for anterior chest wall pain. A retrospective review of these patients' outcomes was obtained through postprocedure interviews. Three of the patients previously had a superficial serratus anterior plane block, which was not as efficacious as the DSPB. The fourth patient had a superficial serratus anterior plane that was difficult to separate with hydrodissection but had improved pain control with a DSPB. We illustrate 4 patients who have benefitted from a DSPB and describe indications that this block may be more efficacious than a superficial serratus plane block. Further study is recommended to understand the intercostal nerve branches within the lateral and anterior muscular chest wall planes.

  2. MOSFET dosimetry in-vivo at superficial and orthovoltage x-ray energies

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Wollongong, NSW

    2003-01-01

    This note investigates in-vivo dosimetry using a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for radiotherapy treatment at superficial and orthovoltage x-ray energies. This was performed within one fraction of the patients treatment. Standard measurements along with energy response of the detector are given. Results showed that the MOSFET measurements in-vivo agreed with calculated results on average within ± 5.6% over all superficial and orthovoltage energies. These variations were slightly larger than TLD results with variations between measured and calculated results being ± 5.0% for the same patient measurements. The MOSFET device provides adequate in-vivo dosimetry for superficial and orthovoltage energy treatments with the accuracy of the measurements seeming to be relatively on par with TLD in our case. The MOSFET does have the advantage of returning a relatively immediate dosimetric result after irradiation. Copyright (2003) Australasian College of Physical Scientists and Engineers in Medicine

  3. Prevalence and causative agents of superficial mycoses in a textile factory in Adana, Turkey.

    Science.gov (United States)

    Celik, E; Ilkit, M; Tanir, F

    2003-09-01

    This study was carried out in a textile factory settled in the city center of Adana, Turkey. The workers were evaluated for the presence of superficial mycoses and the interaction of their working environment or working condition. A total of 431 textile workers were included in the study, with a male to female ratio of 378 (87.7%) to 53 (12.3%) and an age range of 19-52 (mean: 33.7 +/- 6.8). Direct examination and/or culture revealed superficial mycoses in 73 (16.9%) workers, among them 56 (76.7%) were classified as dermatophytoses, 8 (11.0%) as Pityriasis versicolor while in nine (12.3%) of the cases, no causative agent could be determined. Trichophyton rubrum (57.1%) and T. mentagrophytes (42.9%) were the two species isolated on culture. This study emphasized that textile workers should be admitted as a risk group for superficial mycoses, especially tinea pedis.

  4. Investigation of Superficial Resistance of Different Purity Copper at Boiling Nitrogen Temperature Depending on Treatment of Current-Conducting Layer

    International Nuclear Information System (INIS)

    Kutovoj, V.A.; Nikolaenko, A.A.; Stoev, P.I.

    2007-01-01

    Results of this scientific work show influence of annealing temperature and deformation degree of initial MOB copper and after electron beam refining on superficial resistance at temperature of boiling nitrogen. It is shown, that 30 % deformation and annealing in 873...923 K temperature range results in appreciable reduction of superficial resistance at the investigated samples of copper. The lowest values of superficial resistance after thermal and mechanical treatment were observed in the samples after electron beam refinement

  5. Velocity distribution in snow avalanches

    Science.gov (United States)

    Nishimura, K.; Ito, Y.

    1997-12-01

    In order to investigate the detailed structure of snow avalanches, we have made snow flow experiments at the Miyanomori ski jump in Sapporo and systematic observations in the Shiai-dani, Kurobe Canyon. In the winter of 1995-1996, a new device to measure static pressures was used to estimate velocities in the snow cloud that develops above the flowing layer of avalanches. Measurements during a large avalanche in the Shiai-dani which damaged and destroyed some instruments indicate velocities increased rapidly to more than 50 m/s soon after the front. Velocities decreased gradually in the following 10 s. Velocities of the lower flowing layer were also calculated by differencing measurement of impact pressure. Both recordings in the snow cloud and in the flowing layer changed with a similar trend and suggest a close interaction between the two layers. In addition, the velocity showed a periodic change. Power spectrum analysis of the impact pressure and the static pressure depression showed a strong peak at a frequency between 4 and 6 Hz, which might imply the existence of either ordered structure or a series of surges in the flow.

  6. Corte y sellado reversible de dientes para obtener superficies internas de esmalte incólumes

    Directory of Open Access Journals (Sweden)

    Ana Milena Santiago-Medina

    2015-07-01

    Full Text Available Las superficies internas de los dientes, que se obtienen por cortes con discos, están generalmente desorganizadas por los giros, la velocidad y la rugosidad del disco. El calor altera la superficie y el agua de la refrigeración la composición química porque disuelve los componentes. En estudios de difusión, el perfil se borra por el corte, lo que anula resultados. Objetivo: desarrollar un método de sellado de superficies internas, ya cortadas antes de los ensayos de difusión, sin dejar trazas químicas o partículas. Materiales y metedos: se probó in vitro la habilidad de cuatro materiales de sellado con 40 especimenes, provenientes de 20 coronas de terceros molares, cortadas sagitalmente. Los especímenes se distribuyeron aleatoriamente en cuatro grupos (n = 10: G1: Teflón (Topex®, G2: Tela de caucho (Dental DAM®, G3: película de cloruro de polivinilo (Vinilpel® y G4: Cinta aislante (Tesa®. Se usó una solución de azul de metileno (AM al 2% por 6 días como indicadora de filtración. Por observación visual de cada muestra, se le asignó un valor (sí o no dependiendo de la presencia o ausencia de cualquier punto MB sobre la superficie de sellado. Los resultados fueron analizados siguiendo un modelo estadístico de respuesta binomial. Resultados: Siguiendo los procedimientos descritos, el teflón es el único material que previene la filtración de AM en la superficie interna expuesta por el corte. Conclusión: Se propone un protocolo de sellado reversible de las superficies internas con teflón, previo al corte de los dientes, para no alterar los resultados experimentales.

  7. Evaluation of anatomy and variations of superficial palmar arch and upper extremity arteries with CT angiography.

    Science.gov (United States)

    Kaplanoglu, Hatice; Beton, Osman

    2017-04-01

    To evaluate the abnormalities and variations of the arterial system of upper extremities and superficial palmar arch with computed tomography angiography and to guide the clinician during this procedure. A total of 156 upper extremities of 78 cases were retrospectively analyzed using computed tomography angiography. The study was approved by the local ethics committee of the hospital. From the analysis of the computed tomography angiography images, the following information was recorded; the diameters and abnormalities of radial, ulnar and brachial arteries in both upper extremities, the presence of atherosclerotic changes or stenosis in these arteries, whether the superficial palmar arch was complete or incomplete, and arterial dominance. Also, the computed tomography angiography classification of superficial palmar arch distribution and anatomic configuration was performed. The mean baseline diameters of the radial, ulnar and brachial arteries of the cases were; 2.8 ± 0.6, 2.5 ± 0.7, and 4.7 ± 0.6 mm, respectively. A complete superficial palmar arch was observed in 69.2 % of the right hands and 70.5 % of the left hands. For the superficial palmar arches on the right side, the radial artery was dominant in two and the ulnar artery was dominant in 47 with the remaining showing codominance. On the left side, the radial artery was dominant in one hand, with the ulnar artery being dominant in 49 cases, and in 28 cases, there was codominance. In the superficial palmar arch classification, four of the arches (A-D) were defined as complete and the remaining three (E-G) as incomplete. The current study clarified different variations in palmar circulation and forearm arteries to aid the surgeon during trans-radial or trans-ulnar catheterization, hemodialysis, or coronary artery bypass grafting.

  8. Ultrasound of musculoskeletal soft-tissue tumors superficial to the investing fascia.

    Science.gov (United States)

    Hung, Esther Hiu Yee; Griffith, James Francis; Ng, Alex Wing Hung; Lee, Ryan Ka Lok; Lau, Domily Ting Yi; Leung, Jason Chi Shun

    2014-06-01

    The objective of our study was to evaluate the diagnostic accuracy of ultrasound in assessing musculoskeletal soft-tissue tumors superficial to the investing fascia. Seven hundred fourteen superficial soft-tissue tumors evaluated with ultrasound by two musculoskeletal radiologists were retrospectively reviewed. In all ultrasound reports, the reporting radiologists provided one, two, or three diagnoses depending on their perceived level of diagnostic certainty. Two hundred forty-seven tumors had subsequent histologic correlation, thus allowing the accuracy of the ultrasound diagnosis to be determined. Images of the lesions with a discordant ultrasound diagnosis and histologic diagnosis were reviewed, and the ultrasound features were further classified as concordant with the known histologic diagnosis, concordant with the known histologic diagnosis with atypical features present, or discordant with the known histologic diagnosis. Four hundred sixty-seven tumors without pathologic confirmation were followed up clinically. Overall the accuracy of ultrasound examination for assessing superficial soft-tissue masses was 79.0% when all differential diagnoses were considered and 77.0% when only the first differential diagnosis was considered. The sensitivity and specificity of the first ultrasound diagnosis were 95.2% and 94.3%, respectively, for lipoma; 73.0% and 97.7% for vascular malformation; 80.0% and 95.4% for epidermoid cyst; and 68.8% and 95.2% for nerve sheath tumor. Reduced observer awareness of specific tumor entities tended to contribute to underdiagnosis more than poor specificity of ultrasound findings. Most tumors (236/247, 96%) were benign. The sensitivity and specificity of ultrasound for identifying malignant superficial soft-tissue tumors was 94.1% and 99.7%, respectively. The diagnostic accuracy of ultrasound in the assessment of superficial musculoskeletal soft-tissue tumors is high and can be improved through increased radiologist awareness of less

  9. Velocity Estimate Following Air Data System Failure

    National Research Council Canada - National Science Library

    McLaren, Scott A

    2008-01-01

    .... A velocity estimator (VEST) algorithm was developed to combine the inertial and wind velocities to provide an estimate of the aircraft's current true velocity to be used for command path gain scheduling and for display in the cockpit...

  10. Bacterias en superficies contactadas durante las tomas radiográficas intraorales

    OpenAIRE

    Lee, Guihan; Calderón-Ubaquí, Victor; Sacsaquispe-Contreras, Sonia

    2016-01-01

    Objetivo: Determinar la presencia de bacterias mediante el análisis microbiológico en las superficies contactadas por el operador durante la toma y procesado de radiografías intraorales en diferentes momentos del día en el Servicio de Radiología Oral de la UPCH. Materiales y métodos: Se realizó un muestreo en nueve superficies del servicio de radiología oral. Las muestras se tomaron en dos momentos por el mismo investigador; al inicio y al finalizar las actividades en el servicio, se realizó ...

  11. Recent advances in high-throughput molecular marker identification for superficial and invasive bladder cancers

    DEFF Research Database (Denmark)

    Andersen, Lars Dyrskjøt; Zieger, Karsten; Ørntoft, Torben Falck

    2007-01-01

    individually contributed to the management of the disease. However, the development of high-throughput techniques for simultaneous assessment of a large number of markers has allowed classification of tumors into clinically relevant molecular subgroups beyond those possible by pathological classification. Here......Bladder cancer is the fifth most common neoplasm in industrialized countries. Due to frequent recurrences of the superficial form of this disease, bladder cancer ranks as one of the most common cancers. Despite the description of a large number of tumor markers for bladder cancers, none have......, we review the recent advances in high-throughput molecular marker identification for superficial and invasive bladder cancers....

  12. Managment of superficial infantile capillary hemangiomas with topical timolol maleate solution.

    Science.gov (United States)

    Rizvi, Syed Ali Raza; Yusuf, Faraz; Sharma, Rajeev; Rizvi, Syed Wajahat Ali

    2015-01-01

    Capillary hemangioma is the most common benign tumor of eyelids and orbit in children. Recently, a topical beta blocker has been reported as an effective treatment for superficial capillary hemangiomas. We present a case report of two children having large capillary hemangiomas who responded well to topical treatment by 0.5% timolol maleate solution. After 12 months of treatment, the lesion has significantly reduced in size, thickness, and color in both cases. Thus, we conclude that long-term use of topical 0.5% timolol maleate solution is safe and effective in treating superficial capillary hemangiomas.

  13. Superficial Temporal Artery Pseudoaneurysm: A Conservative Approach in a Critically Ill Patient

    International Nuclear Information System (INIS)

    Grasso, Rosario Francesco; Quattrocchi, Carlo Cosimo; Crucitti, Pierfilippo; Carboni, Giampiero; Coppola, Roberto; Zobel, Bruno Beomonte

    2007-01-01

    A 71-year-old man affected by cardio- and cerebrovascular disease experienced an accidental fall and trauma to the fronto-temporal area of the head. A few weeks later a growing mass appeared on his scalp. A diagnosis of superficial temporal artery pseudoaneurysm was made following CT and color Doppler ultrasound. His clinical condition favoured a conservative approach by ultrasound-guided compression and subsequent surgical resection. A conservative approach should be considered the treatment of choice in critically ill patients affected by superficial temporal artery pseudoaneurysm

  14. Secondary superficial siderosis of the central nervous system in a patient presenting with sensorineural hearing loss

    International Nuclear Information System (INIS)

    Lemmerling, M.; De Praeter, G.; Mollet, P.; Mortele, K.; Kunnen, M.; Mastenbroek, G.

    1998-01-01

    We present a 50-year-old man who was investigated for sensorineural hearing loss. On MRI of the brain superficial siderosis of the central nervous system was seen, while MRI of the spine revealed an ependymoma of the cauda equina. This case illustrates the importance of performing T2-weighted imaging of the brain and posterior fossa when sensorineural hearing loss is present. Spine imaging is mandatory when superficial siderosis of the brain is diagnosed without identification of a bleeding source in the brain. (orig.)

  15. Harvest Date Influences Superficial Scald Development in Granny Smith Apples During Long Term Storage

    OpenAIRE

    ERKAN, Mustafa; PEKMEZCİ, Mustafa

    2014-01-01

    The effects of harvest dates on superficial scald development and postharvest quality in 'Granny Smith' apples (Malus domestica Borkh.) were investigated. Apples were harvested at 15-day intervals during 2 consecutive years (2000-2001) and stored at 0 °C with 90% relative humidity for 8 months. At the end of the 8 - month storage period plus an additional 1 week at 20 °C the percentage of superficial scald was lower (24.4%) in late harvested (November 15) apples than in ap...

  16. Caracterizacion dosimetrica del equipo de Terapia Superficial Therapax del Hospital Mexico

    International Nuclear Information System (INIS)

    Bernui De Vivanco, Maria Giselle; Rojas Rivas, Jorge; Cardenas Retuerto, Augusto

    2007-01-01

    The Servicio de Radioterapia of the Hospital Mexico in San Jose, Costa Rica has a Superficial Therapy equipment Therapax model DXT 300. It describes the measurements for the dosimetric characterization of the configurations 100 kVp, 25 mA and filter of 2.4 mm of Al, and 250 kVp, 10 mA and filter of 2.5 mm of Cu, taking into account that the uncertainties in the measurements of the superficial therapy equipment are higher than in the rank of the megavoltage [es

  17. Radiación acústica por superficies planas: Aplicación a altavoces

    OpenAIRE

    Alba, Jesús; Ramis, Jaime; Espinosa, Víctor; Sánchez, Víctor

    2003-01-01

    En los sistemas de reproducción sonora es habitual la utilización de altavoces dinámicos. Sin embargo, en aplicaciones específicas, puede ser necesaria y/o conveniente la utilización de altavoces alternativos con superficies planas como diafragma, como los electrostáticos o los basados en la tecnología NXT© . Estos altavoces generan el campo acústico mediante la vibración de una superficie rectangular. Se puede suponer, en una primera aproximación, que todos los puntos sobre su su...

  18. Metodologia para obtenção do hidrograma de escoamento superficial em encostas e canais. Parte II: modelo computacional e análise de sensibilidade Methodology for obtention of superficial flow hydrograph in hillsides and canals. Part II: computer model and sensitivity analysis

    Directory of Open Access Journals (Sweden)

    José M. A. Silva

    2006-12-01

    Full Text Available Estimativas de vazão máxima de escoamento superficial são necessárias para o projeto de obras hidráulicas em bacias urbanas e rurais. A dificuldade em aplicar os procedimentos disponíveis para calcular a variação do escoamento superficial com o tempo e de seu valor máximo deve-se à inexatidão dos métodos usados para esse objetivo e à variabilidade nos resultados que podem ser obtidos por profissionais que usem o mesmo procedimento. Dessa forma, a investigação de um método que produza estimativas confiáveis da vazão máxima e do hidrograma de escoamento superficial é de grande interesse. Neste trabalho, desenvolveu-se e avaliou-se a sensibilidade de um software (HIDROGRAMA 2.1 que permite a obtenção do hidrograma de escoamento superficial, da vazão máxima e seu tempo de ocorrência, da altura e da velocidade máximas do escoamento, do volume e da lâmina de escoamento superficial em encosta e em canais. O modelo apresentou grande sensibilidade ao período de retorno, à taxa de infiltração estável e ao comprimento da encosta e do canal.Estimative of maximum runoff flow rates are essential for the projects of hydraulic urban and rural basins. The difficulty in applying the available procedures to estimate the temporary variation of the flow rate and its maximum value is due to the inaccuracy of some methods that are usually used and to the big variability of results that can be obtained by different professionals that use the same procedures. Therefore, research of a method that produces trustworthy assessment of peak-flow rates and hydrographs is of great interest. This paper describes the development and sensitivity analysis of a software (HIDROGRAMA 2.1 that allows obtaining surface runoff hydrograph, peak flow rate and its time of occurrence, runoff maximum height, runoff velocity and runoff volume. The model presented great sensibility to precipitation return period, infiltration rate after long time of wetting and

  19. Cosmic string induced peculiar velocities

    International Nuclear Information System (INIS)

    van Dalen, A.; Schramm, D.N.

    1987-02-01

    We calculate analytically the probability distribution for peculiar velocities on scales from 10h -1 to 60h -1 Mpc with cosmic string loops as the dominant source of primordial gravitational perturbations. We consider a range of parameters βGμ appropriate for both hot (HDM) and cold (CDM) dark matter scenarios. An Ω = 1 CDM Universe is assumed with the loops randomly placed on a smooth background. It is shown how the effects can be estimated of loops breaking up and being born with a spectrum of sizes. It is found that to obtain large scale streaming velocities of at least 400 km/s it is necessary that either a large value for βGμ or the effect of loop fissioning and production details be considerable. Specifically, for optimal CDM string parameters Gμ = 10 -6 , β = 9, h = .5, and scales of 60h -1 Mpc, the parent size spectrum must be 36 times larger than the evolved daughter spectrum to achieve peculiar velocities of at least 400 km/s with a probability of 63%. With this scenario the microwave background dipole will be less than 800 km/s with only a 10% probability. The string induced velocity spectrum is relatively flat out to scales of about 2t/sub eq//a/sub eq/ and then drops off rather quickly. The flatness is a signature of string models of galaxy formation. With HDM a larger value of βGμ is necessary for galaxy formation since accretion on small scales starts later. Hence, with HDM, the peculiar velocity spectrum will be larger on large scales and the flat region will extend to larger scales. If large scale peculiar velocities greater than 400 km/s are real then it is concluded that strings plus CDM have difficulties. The advantages of strings plus HDM in this regard will be explored in greater detail in a later paper. 27 refs., 4 figs., 1 tab

  20. Angle independent velocity spectrum determination

    DEFF Research Database (Denmark)

    2014-01-01

    An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral vel...... velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes....

  1. SIMULATIONS OF HIGH-VELOCITY CLOUDS. I. HYDRODYNAMICS AND HIGH-VELOCITY HIGH IONS

    International Nuclear Information System (INIS)

    Kwak, Kyujin; Henley, David B.; Shelton, Robin L.

    2011-01-01

    We present hydrodynamic simulations of high-velocity clouds (HVCs) traveling through the hot, tenuous medium in the Galactic halo. A suite of models was created using the FLASH hydrodynamics code, sampling various cloud sizes, densities, and velocities. In all cases, the cloud-halo interaction ablates material from the clouds. The ablated material falls behind the clouds where it mixes with the ambient medium to produce intermediate-temperature gas, some of which radiatively cools to less than 10,000 K. Using a non-equilibrium ionization algorithm, we track the ionization levels of carbon, nitrogen, and oxygen in the gas throughout the simulation period. We present observation-related predictions, including the expected H I and high ion (C IV, N V, and O VI) column densities on sightlines through the clouds as functions of evolutionary time and off-center distance. The predicted column densities overlap those observed for Complex C. The observations are best matched by clouds that have interacted with the Galactic environment for tens to hundreds of megayears. Given the large distances across which the clouds would travel during such time, our results are consistent with Complex C having an extragalactic origin. The destruction of HVCs is also of interest; the smallest cloud (initial mass ∼ 120 M sun ) lost most of its mass during the simulation period (60 Myr), while the largest cloud (initial mass ∼ 4 x 10 5 M sun ) remained largely intact, although deformed, during its simulation period (240 Myr).

  2. Micrometeorological studies for the characterization of the atmospheric superficial layer in the Valley of Mexico; Estudios micrometeorologicos para la caracterizacion de la capa atmosferica superficial en el Valle de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Saldana Flores, Ricardo; Salcido Gonzalez, Victor A.; Borja Diaz, Marco Antonio R.; Morales Reyes, Maria Flor [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This work establishes the principal aspects related to two micrometeorological campaigns carried out in the Valley of Mexico, the first one from May 19 to 27, 1992 in the vicinity of the Valle de Mexico thermoelectric central and the second from September 13 to 21, 1993 in a site nearby the recreational lake of the Texcoco Plan. The first campaign of measurements encompassed the monitoring at ground level (at a height of 10 meters) of the following parameters: -wind orthogonal components; -temperature; -relative humidity; -Global radiation; - Net radiation; -Atmospheric pressure. Also, simultaneously five daily radio soundings were performed through a captive balloon and free soundings, up to an approximate height of 2500 meters. During the second campaign the same measurements as in the first campaign were carried out, except the radio soundings with the captive balloon, incorporating a turbulence ultrasonic sensor with which, among other parameters, were obtained: -Mean velocities of the wind orthogonal components; -Mean temperature; -Covariance of the wind component z and temperature; -Friction velocity; -Monin-Obukov length; -Vertical heat flow; -Wind mean velocity; -Wind mean direction. [Espanol] En el presente trabajo se anotan los principales aspectos relativos a dos campanas micrometeorologicas realizadas en el Valle de Mexico, la primera del 19 al 27 de mayo de 1992 en las inmediaciones de la central termoelectrica Valle de Mexico y la segunda del 13 al 21 de septiembre de 1993, en un sitio cercano al lago recreativo del Plan Texcoco. La primera campana de mediciones abarco el monitoreo en superficie (a 10 m de altura) de los siguientes parametros: - Componentes ortogonales del viento. - Temperatura. - Humedad relativa. - Radiacion global. - Radiacion neta. - Presion atmosferica. Asimismo, se llevaron a cabo simultaneamente cinco radiosondeos diarios a traves de un globo cautivo y de sondas libres, hasta una altura aproximada de 2500 metros. Durante la

  3. Micrometeorological studies for the characterization of the atmospheric superficial layer in the Valley of Mexico; Estudios micrometeorologicos para la caracterizacion de la capa atmosferica superficial en el Valle de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Saldana Flores, Ricardo; Salcido Gonzalez, Victor A; Borja Diaz, Marco Antonio R.; Morales Reyes, Maria Flor [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This work establishes the principal aspects related to two micrometeorological campaigns carried out in the Valley of Mexico, the first one from May 19 to 27, 1992 in the vicinity of the Valle de Mexico thermoelectric central and the second from September 13 to 21, 1993 in a site nearby the recreational lake of the Texcoco Plan. The first campaign of measurements encompassed the monitoring at ground level (at a height of 10 meters) of the following parameters: -wind orthogonal components; -temperature; -relative humidity; -Global radiation; - Net radiation; -Atmospheric pressure. Also, simultaneously five daily radio soundings were performed through a captive balloon and free soundings, up to an approximate height of 2500 meters. During the second campaign the same measurements as in the first campaign were carried out, except the radio soundings with the captive balloon, incorporating a turbulence ultrasonic sensor with which, among other parameters, were obtained: -Mean velocities of the wind orthogonal components; -Mean temperature; -Covariance of the wind component z and temperature; -Friction velocity; -Monin-Obukov length; -Vertical heat flow; -Wind mean velocity; -Wind mean direction. [Espanol] En el presente trabajo se anotan los principales aspectos relativos a dos campanas micrometeorologicas realizadas en el Valle de Mexico, la primera del 19 al 27 de mayo de 1992 en las inmediaciones de la central termoelectrica Valle de Mexico y la segunda del 13 al 21 de septiembre de 1993, en un sitio cercano al lago recreativo del Plan Texcoco. La primera campana de mediciones abarco el monitoreo en superficie (a 10 m de altura) de los siguientes parametros: - Componentes ortogonales del viento. - Temperatura. - Humedad relativa. - Radiacion global. - Radiacion neta. - Presion atmosferica. Asimismo, se llevaron a cabo simultaneamente cinco radiosondeos diarios a traves de un globo cautivo y de sondas libres, hasta una altura aproximada de 2500 metros. Durante la

  4. Gas turbine

    International Nuclear Information System (INIS)

    Yang, Ok Ryong

    2004-01-01

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  5. ROTATIONAL VELOCITIES FOR M DWARFS

    International Nuclear Information System (INIS)

    Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Barnes, J. R.; Pinfield, D. J.; Gallardo, J.

    2009-01-01

    We present spectroscopic rotation velocities (v sin i) for 56 M dwarf stars using high-resolution Hobby-Eberly Telescope High Resolution Spectrograph red spectroscopy. In addition, we have also determined photometric effective temperatures, masses, and metallicities ([Fe/H]) for some stars observed here and in the literature where we could acquire accurate parallax measurements and relevant photometry. We have increased the number of known v sin i values for mid M stars by around 80% and can confirm a weakly increasing rotation velocity with decreasing effective temperature. Our sample of v sin is peak at low velocities (∼3 km s -1 ). We find a change in the rotational velocity distribution between early M and late M stars, which is likely due to the changing field topology between partially and fully convective stars. There is also a possible further change in the rotational distribution toward the late M dwarfs where dust begins to play a role in the stellar atmospheres. We also link v sin i to age and show how it can be used to provide mid-M star age limits. When all literature velocities for M dwarfs are added to our sample, there are 198 with v sin i ≤ 10 km s -1 and 124 in the mid-to-late M star regime (M3.0-M9.5) where measuring precision optical radial velocities is difficult. In addition, we also search the spectra for any significant Hα emission or absorption. Forty three percent were found to exhibit such emission and could represent young, active objects with high levels of radial-velocity noise. We acquired two epochs of spectra for the star GJ1253 spread by almost one month and the Hα profile changed from showing no clear signs of emission, to exhibiting a clear emission peak. Four stars in our sample appear to be low-mass binaries (GJ1080, GJ3129, Gl802, and LHS3080), with both GJ3129 and Gl802 exhibiting double Hα emission features. The tables presented here will aid any future M star planet search target selection to extract stars with low v

  6. High-velocity winds from a dwarf nova during outburst

    Science.gov (United States)

    Cordova, F. A.; Mason, K. O.

    1982-01-01

    An ultraviolet spectrum of the dwarf nova TW Vir during an optical outburst shows shortward-shifted absorption features with edge velocities as high as 4800 km/s, about the escape velocity of a white dwarf. A comparison of this spectrum with the UV spectra of other cataclysmic variables suggests that mass loss is evident only for systems with relatively high luminosities (more than about 10 solar luminosities) and low inclination angles with respect to the observer's line of sight. The mass loss rate for cataclysmic variables is of order 10 to the -11th solar mass per yr; this is from 0.01 to 0.001 of the mass accretion rate onto the compact star in the binary. The mass loss may occur by a mechanism similar to that invoked for early-type stars, i.e., radiation absorbed in the lines accelerates the accreting gas to the high velocities observed.

  7. Major therapeutic effect of pentoxifylline-tocopherol association in the superficial radioinduced fibrosis: phase II test

    International Nuclear Information System (INIS)

    Delanian, S.; Balla-Mekias, S.; Maylin, C.; Lefaix, J.L.

    1997-01-01

    The association of pentoxifylline-tocopherol seems efficient in the reduction of the superficial human radioinduced fibrosis. This phase II invites to realize a randomized test and to a comparison with the results got with the dismutase superoxide. (N.C.)

  8. Primary temporal region squamous cell carcinoma diagnosed by a superficial temporal artery biopsy

    DEFF Research Database (Denmark)

    Andersen, S A W; Kiss, K

    2015-01-01

    artery biopsy was performed. The histopathology revealed perineural invasion of squamous cell carcinoma (SCC). A thorough investigation revealed no other primary site for the SCC and the patient was treated with surgical excision. CONCLUSION: Malignancy is rarely found in superficial temporal artery...

  9. Automatic and Deliberate Affective Associations with Sexual Stimuli in Women with Superficial Dyspareunia

    NARCIS (Netherlands)

    Brauer, Marieke; de Jong, Peter J.; Huijding, Jorg; Laan, Ellen; ter Kuile, Moniek M.

    Current views suggest that in women with superficial dyspareunia the prospect of penile-vaginal intercourse automatically activates fear-related associations. The automatic activation of negative associations is assumed to interfere with the development of sexual arousal. In turn, this may further

  10. Treatment of primary cutaneous anaplastic large cell lymphoma with superficial x-rays

    DEFF Research Database (Denmark)

    Jepsen, Malene E; Gniadecki, Robert

    2015-01-01

    The optimal radiation schedule for primary cutaneous anaplastic lymphoma (PCALCL) has not been investigated. We report here satisfactory outcomes of low-dose (16-20 Gy, 3-5 fractions), superficial X-ray radiation (40-50 kV) in a series of 10 patients with PCALCL. Only 1 patient developed a local...

  11. Removal of dissolved organic carbon in pilot wetlands of subsuperficial and superficial flows

    Directory of Open Access Journals (Sweden)

    Ruth M. Agudelo C

    2010-04-01

    Full Text Available Objective: to compare removal of dissolved organic carbon (d o c obtained with pilot wetlands of subsuperficial flow (p h s s and superficial flow (p h s, with Phragmites australis as treatment alternatives for domestic residual waters of small communities and rural areas. Methodology: an exploratory and experimental study was carried out adding 100,12 mg/L of dissolved organic carbon to synthetic water contaminated with Chlorpyrifos in order to feed the wetlands. A total amount of 20 samples were done, 16 of them in four experiments and the other ones in the intervals with no use of pesticides. Samples were taken on days 1, 4, 8, and 11 in the six wetlands, three of them subsuperficial, and three of them superficial. The main variable answer was dissolved organic carbon, measured in the organic carbon analyzer. Results: a high efficiency in the removal of d o c was obtained with the two types of wetlands: 92,3% with subsuperficial flow and 95,6% with superficial flow. Such a high removal was due to the interaction between plants, gravel and microorganisms. Conclusion: although in both types of wetlands the removal was high and similar, it is recommended to use those of subsuperficial flow because in the superficial ones algae and gelatinous bio-films are developed, which becomes favorable to the development of important epidemiologic vectors in terms of public health.

  12. Honey compared with silver sulphadiazine in the treatment of superficial partial-thickness burns.

    Science.gov (United States)

    Malik, Kamran Ishaque; Malik, M A Nasir; Aslam, Azhar

    2010-10-01

    Burn injury is associated with a high incidence of death and disability; yet, its management remains problematic and costly. We conducted this clinical study to evaluate the efficacy of honey in the treatment of superficial and partial-thickness burns covering less than 40% of body surface area and compared its results with those of silver sulphadiazine (SSD). In this randomised comparative clinical trial, carried out Burn Center of POF Hospital, Wah Cantt, Pakistan, from May 2007 to February 2008, 150 patients of all ages having similar types of superficial and partial-thickness burns at two sites on different parts of body were included. Each patient had one burn site treated with honey and one treated with topical SSD, randomly. The rate of re-epithelialization and healing of superficial and partial-thickness burns was significantly faster in the sites treated with honey than in the sites treated with SSD (13·47 ± 4·06 versus 15·62 ± 4·40 days, respectively: P honey healed completely in less than 21 days versus 24 days for the site treated with SSD. Six patients had positive culture for Pseudomonas aeroginsa in honey-treated site, whereas 27 patients had positive culture in SSD-treated site. The results clearly showed greater efficacy of honey over SSD cream for treating superficial and partial-thickness burns. 2010 The Authors. Journal Compilation © 2010 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

  13. Thrombophlebitis of the penile superficial vein, penile mondor's disease: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Hyun; Kim, Young Hwa; Kim, Doo Sang; Shin, Hyung Chul; Bae, Won Kyung; Kim, Il Young [Soonchunhyang University, Chunan (Korea, Republic of); Kim, Hyun Cheol [Kyung-Hee University, Seoul (Korea, Republic of)

    2007-07-15

    Mondor's disease is commonly known as thrombophlebitis of the superficial vein in the breast, and this disease occurs rarely in the penis. Despite extensive information about the clinical presentation and course of this disease, imaging findings for this disease are limited. We report gray scale and power Doppler sonographic findings of penile Mondor's disease.

  14. Protocolo nacional de monitoreo de la calidad de los en cuerpos naturales de agua superficial

    OpenAIRE

    Autoridad Nacional del Agua. Dirección de Gestión de Calidad de los Recursos Hídricos

    2011-01-01

    Estandariza la metodología para el desarrollo del monitoreo de la calidad de los recursos hídricos en los cuerpos naturales de agua superficial, asimismo pretende convertirse en un instrumento de gestión en el desarrollo del Plan Nacional de Vigilancia de la Calidad de Agua en el Perú.

  15. The defence architecture of the superficial cells of the oral mucosa

    NARCIS (Netherlands)

    Asikainen, P.; Ruotsalainen, T.J.; Mikkonen, J.J.W.; Koistinen, A.; ten Bruggenkate, C.M.; Kullaa, A.M.

    2012-01-01

    The oral epithelium together with the saliva and its components forms a complex structure which is the first line of defence in the oral cavity. The surface of superficial cells of the oral epithelium contains ridge-like folds, microplicae (MPL), which are typical of the surfaces of areas covered

  16. The Effects of Test Anxiety on Learning at Superficial and Deep Levels of Processing.

    Science.gov (United States)

    Weinstein, Claire E.; And Others

    1982-01-01

    Using a deep-level processing strategy, low test-anxious college students performed significantly better than high test-anxious students in learning a paired-associate word list. Using a superficial-level processing strategy resulted in no significant difference in performance. A cognitive-attentional theory and test anxiety mechanisms are…

  17. The flexural stiffness of superficial neuromasts in the zebrafish (Danio rerio) lateral line

    NARCIS (Netherlands)

    McHenry, Matthew J.; van Netten, Sietse M.

    2007-01-01

    Superficial neuromasts are structures that detect water flow on the surface of the body of fish and amphibians. As a component of the lateral line system, these receptors are distributed along the body, where they sense flow patterns that mediate a wide variety of behaviors. Their ability to detect

  18. Subintimal angioplasty for the treatment of long segment occlusion of superficial femoral artery: the midterm results

    International Nuclear Information System (INIS)

    Lou Wensheng; Gu Jianping; He Xu; Chen Liang; Chen Guoping; Su Haobo; Song Jinhua; Wang Tao; Xu Ke

    2011-01-01

    Objective: To discuss the clinical value of subintimal angioplasty in treating long segment occlusion of superficial femoral artery and to observe its midterm results. Methods: Subintimal angioplasty was performed in 45 patients with long segment occlusion of superficial femoral artery, whose clinical presentation was intermittent claudication or critical limb ischemia. The primary patency, limb salvage and factors influencing long-term patency were observed, and the clinical data were analyzed. Results: Of the total 45 cases, the subintimal angioplasty was successfully accomplished in 43. The success rate of antegrade approach technique via the superficial femoral artery was 80% (n=36), the occlusion was recanalized by using retrograde approach technique via ipsilateral popliteal artery in 7 case. The total technical success rate was 95.6%. The primary patency in 43 successful cases at 6, 12, 24 and 36 months was 85.7%, 69.0% 57.3% and 50.9%, respectively. No statistically significant difference in primary patency existed between the group of intermittent claudication and the group of critical limb ischemia (P>0.05). Statistically significant prediction factors for primary patency included the number of the run off vessels below the knee and the length of the occlusion (P<0.05). Conclusion: Subintimal angioplasty is an effective procedure for the treatment of long segment occlusions of superficial femoral artery with satisfactory mid-term results. (authors)

  19. The analogy between dreams and the ancient art of memory is tempting but superficial.

    Science.gov (United States)

    Axmacher, Nikolai; Fell, Juergen

    2013-12-01

    Although the analogy between dreams and ancient mnemotechniques is tempting because they share several phenomenological characteristics, this analogy is superficial at a closer look. Unlike mneomotechnically encoded material, rapid eye movement (REM) dreams are inherently difficult to remember, do not usually allow conscious subsequent retrieval of all interconnected elements, and have been found to support subsequent episodic memory in only rare cases.

  20. Masaje circulatorio superficial en la enfermedad arterial periférica

    OpenAIRE

    Cebrià Iranzo, M. Àngels

    2010-01-01

    En la enfermedad arterial periférica crónica se indica el masaje circulatorio superficial por producir una vasodilatación refleja en las zonas afectadas. Este masaje manual tiene dos objetivos fundamentales: 1) Favorecer la vasodilatación refleja e hiperemia local; 2) Drenar el retorno vascular sanguíneo y linfático.

  1. Percutaneous transluminal angioplasty of the superficial femoral artery by retrograde catheterization via the popliteal artery

    DEFF Research Database (Denmark)

    Tønnesen, K H; Sager, P; Karle, A

    1988-01-01

    We report the results of 50 angioplasty procedures via the popliteal artery. A 3-year follow-up including control of blood pressures at ankle and toe levels show results comparable to reports in the literature. This new approach for angioplasty of the superficial femoral artery and eventually of ...

  2. Patient Perception of Imiquimod Treatment for Actinic Keratosis and Superficial Basal Cell Carcinoma in 202 Patients

    NARCIS (Netherlands)

    Waalboer-Spuij, Rick; Holterhues, Cynthia; van Hattem, Simone; Schuttelaar, Marie Louise A.; Gaastra, Menno T. W.; Kuijpers, Danielle I. M.; Hollestein, Loes M.; Nijsten, Tamar E. C.

    2015-01-01

    Objective: To document the impact on patient-reported outcomes and health-related quality of life (HRQoL) of treatment with imiquimod cream in patients with actinic keratosis (AK) and superficial basal cell carcinoma (sBCC). Methods: This open-label, multicenter study included AK and sBCC patients

  3. Induction of superficial cortical layer neurons from mouse embryonic stem cells by valproic acid.

    Science.gov (United States)

    Juliandi, Berry; Abematsu, Masahiko; Sanosaka, Tsukasa; Tsujimura, Keita; Smith, Austin; Nakashima, Kinichi

    2012-01-01

    Within the developing mammalian cortex, neural progenitors first generate deep-layer neurons and subsequently more superficial-layer neurons, in an inside-out manner. It has been reported recently that mouse embryonic stem cells (mESCs) can, to some extent, recapitulate cortical development in vitro, with the sequential appearance of neurogenesis markers resembling that in the developing cortex. However, mESCs can only recapitulate early corticogenesis; superficial-layer neurons, which are normally produced in later developmental periods in vivo, are under-represented. This failure of mESCs to reproduce later corticogenesis in vitro implies the existence of crucial factor(s) that are absent or uninduced in existing culture systems. Here we show that mESCs can give rise to superficial-layer neurons efficiently when treated with valproic acid (VPA), a histone deacetylase inhibitor. VPA treatment increased the production of Cux1-positive superficial-layer neurons, and decreased that of Ctip2-positive deep-layer neurons. These results shed new light on the mechanisms of later corticogenesis. Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  4. Improved superficial brain hemorrhage visualization in susceptibility weighted images by constrained minimum intensity projection

    Science.gov (United States)

    Castro, Marcelo A.; Pham, Dzung L.; Butman, John

    2016-03-01

    Minimum intensity projection is a technique commonly used to display magnetic resonance susceptibility weighted images, allowing the observer to better visualize hemorrhages and vasculature. The technique displays the minimum intensity in a given projection within a thick slab, allowing different connectivity patterns to be easily revealed. Unfortunately, the low signal intensity of the skull within the thick slab can mask superficial tissues near the skull base and other regions. Because superficial microhemorrhages are a common feature of traumatic brain injury, this effect limits the ability to proper diagnose and follow up patients. In order to overcome this limitation, we developed a method to allow minimum intensity projection to properly display superficial tissues adjacent to the skull. Our approach is based on two brain masks, the largest of which includes extracerebral voxels. The analysis of the rind within both masks containing the actual brain boundary allows reclassification of those voxels initially missed in the smaller mask. Morphological operations are applied to guarantee accuracy and topological correctness, and the mean intensity within the mask is assigned to all outer voxels. This prevents bone from dominating superficial regions in the projection, enabling superior visualization of cortical hemorrhages and vessels.

  5. Effect of exposing pupae of flesh fly Parasarcophaga ruficornis F. to superficial X-rays

    International Nuclear Information System (INIS)

    Kumar, K.; Srivastava, U.S.

    1991-01-01

    Irradiation of pupae of Parasarcophaga ruficornis with different doses of superficial X-rays leads to lethality and interference with moulting and metamorphosis. Younger pupae are more radiosensitive in respect of lethality and metamorphosis to older ones. (author). 12 ref., 9 figs., 1 tab

  6. The properties of tagged lattice fluids: II. Velocity correlation functions

    International Nuclear Information System (INIS)

    Binder, P.M.; d'Humieres, D.; Poujol, L.

    1988-01-01

    We report preliminary measurements of the velocity autocorrelation function for a tagged particle in a lattice gas. These measurements agree with the Boltzmann-level theory. The Green-Kubo integration of these measurements agrees with theoretical predictions for the diffusion coefficient. To within the error bars of the simulations (3 /times/ 10/sup /minus/3/) we observe no long-time tails. 9 refs., 1 fig., 1 tab

  7. Pneumodissection for skin protection in image-guided cryoablation of superficial musculoskeletal tumours.

    Science.gov (United States)

    Maybody, Majid; Tang, Peter Q; Moskowitz, Chaya S; Hsu, Meier; Yarmohammadi, Hooman; Boas, F Edward

    2017-03-01

    Pneumodissection is described as a simple method for preventing skin injury during cryoablation of superficial musculoskeletal tumours. Superficial tumour cryoablations performed from 2009 to 2015 were retrospectively reviewed. Pneumodissection was performed in 13 patients when the shortest tumour-skin distance was less than 25 mm. Indications were pain palliation (n = 9) and local tumour control (n = 4). Patients, target tumours, technical characteristics and complications up to 60 days post ablation were reviewed. The ice ball-skin distances with and without pneumodissection were compared by a paired t-test and further assessed for association with covariates using ANCOVA. Technical success for ablation was 12 of 13. The mean shortest tumour-skin distance was 15.0 mm (3.2-24.5 mm). The mean thickness of pneumodissection was 9.6 mm (5.2-16.6 mm) resulting in mean elevation of skin of 3.4 mm (1.2-5.3 mm). Mean shortest ice ball-skin distance after pneumodissection was 10.5 mm (4.2-19.7 mm). No infection or systemic air embolism was noted. No intraprocedural frostbite was observed. Pneumodissection is feasible, effective and safe in protecting the skin during image-guided cryoablation of superficial tumours. • Frostbite during image-guided cryoablation of superficial tumours is commonly under-reported. • Frostbites are painful and may introduce infection into the superficial ablation zone. • Warm compress, saline and CO 2 have shortcomings in protecting the skin. • Pneumodissection is free, readily available, easy to use and safe and effective.

  8. Investigation of the behaviour of a LILW superficial repository under aircraft impact

    International Nuclear Information System (INIS)

    Lo Frano, Rosa; Stefanini, Lorenzo

    2016-01-01

    Highlights: • Safety assessment of a LILW superficial repository. • Investigation of the consequences of an aircraft impact with fuel burning. • Experimental material properties. • Numerical simulation of aircraft impact with fuel burning accident by MSC.MARC"© code. • Demonstration that the overall integrity resulted is guaranteed. - Abstract: Safety and security are the two fundamental aspects to guarantee when designing a LILW superficial repository. Because of its safety concern, we have to prove, and build confidence in, the primary and secondary consequences of the crashing will be acceptable. These goals are obtained generally by means of safety assessment supported by calculations. This study is intended to investigate the performance of a superficial repository subjected to aircraft impact and fuel burning. To the purpose a superficial repository similar to that of El Cabril has been considered. Moreover to be confident the facility is safe and that the consequences of such a type of accident on the environment and humans are negligible, an appropriate safety assessment was carried out. The potential damage that aircraft impact could bring into the repository has been therefore analysed and discussed. To attain the intent load functions, calculated according to the Riera approach, and the maximum temperature reached by fuel during its combustion have been considered. FEM (thermo-mechanical) simulations have been done, by MSC"© Marc code, assuming damaging phenomena of concrete and material properties variation with the temperature. The obtained results showed that an empty superficial repository with a wall thickness, ranging from 0.7 to 1 m, is not sufficient to avoid penetration. Nevertheless even in presence of a reduced strength and of (cone) cracking and plugging, the overall integrity resulted guaranteed.

  9. Investigation of the behaviour of a LILW superficial repository under aircraft impact

    Energy Technology Data Exchange (ETDEWEB)

    Lo Frano, Rosa, E-mail: rosa.lofrano@ing.unipi.it; Stefanini, Lorenzo

    2016-04-15

    Highlights: • Safety assessment of a LILW superficial repository. • Investigation of the consequences of an aircraft impact with fuel burning. • Experimental material properties. • Numerical simulation of aircraft impact with fuel burning accident by MSC.MARC{sup ©} code. • Demonstration that the overall integrity resulted is guaranteed. - Abstract: Safety and security are the two fundamental aspects to guarantee when designing a LILW superficial repository. Because of its safety concern, we have to prove, and build confidence in, the primary and secondary consequences of the crashing will be acceptable. These goals are obtained generally by means of safety assessment supported by calculations. This study is intended to investigate the performance of a superficial repository subjected to aircraft impact and fuel burning. To the purpose a superficial repository similar to that of El Cabril has been considered. Moreover to be confident the facility is safe and that the consequences of such a type of accident on the environment and humans are negligible, an appropriate safety assessment was carried out. The potential damage that aircraft impact could bring into the repository has been therefore analysed and discussed. To attain the intent load functions, calculated according to the Riera approach, and the maximum temperature reached by fuel during its combustion have been considered. FEM (thermo-mechanical) simulations have been done, by MSC{sup ©} Marc code, assuming damaging phenomena of concrete and material properties variation with the temperature. The obtained results showed that an empty superficial repository with a wall thickness, ranging from 0.7 to 1 m, is not sufficient to avoid penetration. Nevertheless even in presence of a reduced strength and of (cone) cracking and plugging, the overall integrity resulted guaranteed.

  10. Use of superficial peroneal nerve graft for treating peripheral nerve injuries

    Directory of Open Access Journals (Sweden)

    Samuel Ribak

    2016-02-01

    Full Text Available ABSTRACT OBJECTIVE: To evaluate the clinical results from treating chronic peripheral nerve injuries using the superficial peroneal nerve as a graft donor source. METHODS: This was a study on eleven patients with peripheral nerve injuries in the upper limbs that were treated with grafts from the sensitive branch of the superficial peroneal nerve. The mean time interval between the dates of the injury and surgery was 93 days. The ulnar nerve was injured in eight cases and the median nerve in six. There were three cases of injury to both nerves. In the surgery, a longitudinal incision was made on the anterolateral face of the ankle, thus viewing the superficial peroneal nerve, which was located anteriorly to the extensor digitorum longus muscle. Proximally, the deep fascia between the extensor digitorum longus and the peroneal longus muscles was dissected. Next, the motor branch of the short peroneal muscle (one of the branches of the superficial peroneal nerve was identified. The proximal limit of the sensitive branch was found at this point. RESULTS: The average space between the nerve stumps was 3.8 cm. The average length of the grafts was 16.44 cm. The number of segments used was two to four cables. In evaluating the recovery of sensitivity, 27.2% evolved to S2+, 54.5% to S3 and 18.1% to S3+. Regarding motor recovery, 72.7% presented grade 4 and 27.2% grade 3. There was no motor deficit in the donor area. A sensitive deficit in the lateral dorsal region of the ankle and the dorsal region of the foot was observed. None of the patients presented complaints in relation to walking. CONCLUSIONS: Use of the superficial peroneal nerve as a graft source for treating peripheral nerve injuries is safe and provides good clinical results similar to those from other nerve graft sources.

  11. [NEII] Line Velocity Structure of Ultracompact HII Regions

    Science.gov (United States)

    Okamoto, Yoshiko K.; Kataza, Hirokazu; Yamashita, Takuya; Miyata, Takashi; Sako, Shigeyuki; Honda, Mitsuhiko; Onaka, Takashi; Fujiyoshi, Takuya

    Newly formed massive stars are embedded in their natal molecular clouds and are observed as ultracompact HII regions. They emit strong ionic lines such as [NeII] 12.8 micron. Since Ne is ionized by UV photons of E>21.6eV which is higher than the ionization energy of hydrogen atoms the line probes the ionized gas near the ionizing stars. This enables to probe gas motion in the vicinity of recently-formed massive stars. High angular and spectral resolution observations of the [NeII] line will thus provide siginificant information on structures (e.g. disks and outflows) generated through massive star formation. We made [NeII] spectroscopy of ultracompact HII regions using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the 8.2m Subaru Telescope in July 2002. Spatial and spectral resolutions were 0.5"" and 10000 respectively. Among the targets G45.12+0.13 shows the largest spatial variation in velocity. The brightest area of G45.12+0.13 has the largest line width in the object. The total velocity deviation amounts to 50km/s (peak to peak value) in the observed area. We report the velocity structure of [NeII] emission of G45.12+0.13 and discuss the gas motion near the ionizing star.

  12. Is superficial burn caused by ultraviolet radiation (sunburn) comparable to superficial burn caused by heat--a histomorphological comparison by in vivo Reflectance-Mode-Confocal Microscopy.

    Science.gov (United States)

    Altintas, M A; Altintas, A A; Guggenheim, M; Busch, K H; Niederbichler, A D; Aust, M C; Vogt, P M

    2009-12-01

    Regardless of the underlying cause, both sunburn and superficial thermal injuries are classified as first-degree burns, since data on morphological differences are scarce. Reflectance-Mode-Confocal Microscopy (RMCM) enables high-resolution non-invasive investigation of the human skin. We studied in vivo histomorphological alterations in both sunburn and superficial thermal injuries using RMCM. Ten patients (6 female, 4 male; aged 28.4 +/- 10.6 years) with first-degree thermal-contact Injuries (TI group), and 9 sunburned patients (SB group; 7 female, 2 male; aged 30.2 +/- 16.4 years), to a maximum extent of 10% of the body surface were evaluated 24 h after burn injury using RMCM. The following parameters were obtained using RMCM: stratum corneum thickness, epidermal thickness, basal layer thickness, granular cell size. Compared to the controls (12.8 +/- 2.5 microm), stratum corneum thickness decreased significantly to 10.6 +/- 2.1 microm in the TI group, whereas it increased significantly to 16.4 +/- 3.1 microm in the SB group. The epidermal thickness did not differ significantly in the TI group (47.9 +/- 2.3 microm) and SB group (49.1 +/- 3.5 microm); however, both increased significantly compared to their respective controls (41.8 +/- 1.4 microm). The basal layer thickness increased more in the SB group compared to the TI group (17.9 +/- 1.4 microm vs. 15.6 +/- 1.1 microm). Both differed also significantly compared to their controls (13.8 +/- 0.9 microm). The granular cell size increased significantly in both groups compared to the controls (731 +/- 42 microm); however, a significantly higher increase was observed in the TI group (852 +/- 58 microm) compared to the SB group (784 +/- 61 microm). Ultraviolet radiation seems to influence predominantly deeper epidermal layers, whereas heat-induced burns affect more superficial epidermal layers. The term 'First-degree burn' should not be used synonymously for sunburn and superficial thermal burn injuries. Conflicts of

  13. Optic-microwave mixing velocimeter for superhigh velocity measurement

    International Nuclear Information System (INIS)

    Weng Jidong; Wang Xiang; Tao Tianjiong; Liu Cangli; Tan Hua

    2011-01-01

    The phenomenon that a light beam reflected off a moving object experiences a Doppler shift in its frequency underlies practical interferometric techniques for remote velocity measurements, such as velocity interferometer system for any reflector (VISAR), displacement interferometer system for any reflector (DISAR), and photonic Doppler velocimetry (PDV). While VISAR velocimeters are often bewildered by the fringe loss upon high-acceleration dynamic process diagnosis, the optic-fiber velocimeters such as DISAR and PDV, on the other hand, are puzzled by high velocity measurement over 10 km/s, due to the demand for the high bandwidth digitizer. Here, we describe a new optic-microwave mixing velocimeter (OMV) for super-high velocity measurements. By using currently available commercial microwave products, we have constructed a simple, compact, and reliable OMV device, and have successfully obtained, with a digitizer of bandwidth 6 GH only, the precise velocity history of an aluminum flyer plate being accelerated up to 11.2 km/s in a three stage gas-gun experiment.

  14. 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...

  15. Experimental study on cryogenic adsorption of methane by activated carbon for helium coolant purification of High-Temperature Gas-cooled Reactor

    International Nuclear Information System (INIS)

    Chang, Hua; Wu, Zong-Xin; Jia, Hai-Jun

    2017-01-01

    Highlights: • The cryogenic CH 4 adsorption on activated carbon was studied for design of HTGR. • The breakthrough curves at different conditions were analyzed by the MTZ model. • The CH 4 adsorption isotherm was fitted well by the Toth model and the D-R model. • The work provides valuable reference data for helium coolant purification of HTGR. - Abstract: The cryogenic adsorption behavior of methane on activated carbon was investigated for helium coolant purification of high-temperature gas-cooled reactor by using dynamic column breakthrough method. With helium as carrier gas, experiments were performed at −196 °C and low methane partial pressure range of 0–120 Pa. The breakthrough curves at different superficial velocities and different feed concentrations were measured and analyzed by the mass-transfer zone model. The methane single-component adsorption isotherm was obtained and fitted well by the Toth model and the Dubinin-Radushkevich model. The adsorption heat of methane on activated carbon was estimated. The cryogenic adsorption process of methane on activated carbon has been verified to be effective for helium coolant purification of high-temperature gas-cooled reactor.

  16. Numerical calculation of velocity distribution near a vertical flat plate immersed in bubble flow

    International Nuclear Information System (INIS)

    Matsuura, Akihiro; Nakamura, Hajime; Horihata, Hideyuki; Hiraoka, Setsuro; Aragaki, Tsutomu; Yamada, Ikuho; Isoda, Shinji.

    1992-01-01

    Liquid and gas velocity distributions for bubble flow near a vertical flat plate were calculated numerically by using the SIMPLER method, where the flow was assumed to be laminar, two-dimensional, and at steady state. The two-fluid flow model was used in the numerical analysis. To calculate the drag force on a small bubble, Stokes' law for a rigid sphere is applicable. The dimensionless velocity distributions which were arranged with characteristic boundary layer thickness and maximum liquid velocity were adjusted with a single line and their forms were similar to that for single-phase wall-jet flow. The average wall shear stress derived from the velocity gradient at the plate wall was strongly affected by bubble diameter but not by inlet liquid velocity. The present dimensionless velocity distributions obtained numerically agreed well with previous experimental results, and the proposed numerical algorithm was validated. (author)

  17. Sound velocity of tantalum under shock compression in the 18–142 GPa range

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Feng, E-mail: xifeng@caep.cn; Jin, Ke; Cai, Lingcang, E-mail: cai-lingcang@aliyun.com; Geng, Huayun; Tan, Ye; Li, Jun [National Key Laboratory of Shock Waves and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102 Mianyang, Sichuan 621999 (China)

    2015-05-14

    Dynamic compression experiments of tantalum (Ta) within a shock pressure range from 18–142 GPa were conducted driven by explosive, a two-stage light gas gun, and a powder gun, respectively. The time-resolved Ta/LiF (lithium fluoride) interface velocity profiles were recorded with a displacement interferometer system for any reflector. Sound velocities of Ta were obtained from the peak state time duration measurements with the step-sample technique and the direct-reverse impact technique. The uncertainty of measured sound velocities were analyzed carefully, which suggests that the symmetrical impact method with step-samples is more accurate for sound velocity measurement, and the most important parameter in this type experiment is the accurate sample/window particle velocity profile, especially the accurate peak state time duration. From these carefully analyzed sound velocity data, no evidence of a phase transition was found up to the shock melting pressure of Ta.

  18. Precollisional velocity correlations in a hard-disk fluid with dissipative collisions.

    Science.gov (United States)

    Soto, R; Piasecki, J; Mareschal, M

    2001-09-01

    Velocity correlations are studied in granular fluids, modeled by the inelastic hard sphere gas. Making a density expansion of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for the evolution of the reduced distributions, we predict the presence of precollisional velocity correlations. They are created by the propagation through correlated sequences of collisions (ring events) of the velocity correlations generated after dissipative collisions. The correlations have their origin in the dissipative character of collisions, being always present in granular fluids. The correlations, that manifest microscopically as an alignment of the velocities of a colliding pair produce modifications of collisional averages, in particular, the virial pressure. The pressure shows a reduction with respect to the elastic case as a consequence of the velocity alignment. Good qualitative agreement is obtained for the comparison of the numerical evaluations of the obtained analytical expressions and molecular dynamics results that showed evidence of precollisional velocity correlations [R. Soto and M. Mareschal, Phys. Rev. E 63, 041303 (2001)].

  19. Study of void fraction and mixing of immiscible liquids in a pool configuration by an upward gas flow

    International Nuclear Information System (INIS)

    Casas, J.C.; Corradini, M.L.

    1992-01-01

    In this paper, investigations are performed to study the mixing between immiscible liquids in a pool configuration due to an upward gas flow. A water-R113 system is sued in the bubbly/churn-turbulent regimes to determine the effects of the unagitated pool depth on layer mixing. The superficial gas velocity at which full mixing is attained is observed to increase with the pool depth, although it is concluded that this is a weak dependency. Mixing in the churn-turbulent regime is studied with Wood's metal-water and Wood's metal-silicone fluid (100 cS) as pairs of fluids. Additional past mixing data from six other fluids are also included in the data base. A criterion is proposed to determine if two liquids will entrain in bubbly or churn-turbulent flow. Correlations are derived that, for a set of given conditions, allow prediction of the mixing state (mixed or segregated) of a system. Because of the indirect method of measuring the mixed layer thickness, pool void fraction experiments are also performed. For the case of water and R113, the effect of unagitated pool depth on the void fraction is studied

  20. Distribution characteristics of interfacial parameter in downward gas-liquid two-phase flow in vertical circular tube

    International Nuclear Information System (INIS)

    Liu Guoqiang; Yan Changqi; Tian Daogui; Sun Licheng

    2014-01-01

    Experimental study was performed on distribution characteristics of interfacial parameters of downward gas-liquid flow in a vertical circular tube with the measurement by a two-sensor optical fiber probe. The test section is a circular pipe with the inner diameter of 50 mm and the length of 2000 mm. The superficial velocities of the gas and the liquid phases cover the ranges of 0.004-0.077 m/s and 0.43-0.71 m/s, respectively. The results show that the distributions of the interfacial parameters in downward bubbly flows are quite different from those in upward bubbly flows. For the case of upward flow, the parameters present the 'wall-peak' or 'core-peak' distributions, but for the case of downward flow, they show 'wall-peak' or 'wide-peak' distributions. The average value of void fraction in vertical downward flow is about 119.6%-145.0% larger than that in upward flow, and the interfacial area concentration is about 18.8%-82.5% larger than that in upward flow. The distribution of interfacial parameters shows an obvious tendency of uniformity. (authors)

  1. Application of Electromagnetic Induction Technique to Measure the Void Fraction in Oil/Gas Two Phase Flow

    Science.gov (United States)

    Wahhab, H. A. Abdul; Aziz, A. R. A.; Al-Kayiem, H. H.; Nasif, M. S.; Reda, M. N.

    2018-03-01

    In this work, electromagnetic induction technique of measuring void fraction in liquid/gas fuel flow was utilized. In order to improve the electric properties of liquid fuel, an iron oxide Fe3O4 nanoparticles at 3% was blended to enhance the liquid fuel magnetization. Experiments have been conducted for a wide range of liquid and gas superficial velocities. From the experimental results, it was realized that there is an existing linear relationship between the void fraction and the measured electromotive force, when induction coils were connected in series for excitation coils, regardless of increase or decrease CNG bubbles distribution in liquid fuel flow. Therefore, it was revealed that the utilized method yielded quite reasonable account for measuring the void fraction, showing good agreement with the other available measurement techniques in the two-phase flow, and also with the published literature of the bubbly flow pattern. From the results of the present investigation, it has been proven that the electromagnetic induction is a feasible technique for the actual measurement of void fraction in a Diesel/CNG fuel flow.

  2. Velocity distribution of fragments of catastrophic impacts

    Science.gov (United States)

    Takagi, Yasuhiko; Kato, Manabu; Mizutani, Hitoshi

    1992-01-01

    Three dimensional velocities of fragments produced by laboratory impact experiments were measured for basalts and pyrophyllites. The velocity distribution of fragments obtained shows that the velocity range of the major fragments is rather narrow, at most within a factor of 3 and that no clear dependence of velocity on the fragment mass is observed. The NonDimensional Impact Stress (NDIS) defined by Mizutani et al. (1990) is found to be an appropriate scaling parameter to describe the overall fragment velocity as well as the antipodal velocity.

  3. Depletion of elements in shock-driven gas

    International Nuclear Information System (INIS)

    Gondhalekar, P.M.

    1985-01-01

    The depletion of elements in shocked gas in supernova remnants and in interstellar bubbles is examined. It is shown that elements are depleted in varying degrees in gas filaments shocked to velocities up to 200 km s -1 and that large differences in depletions are observed in gas filaments shocked to similar velocities. In the shocked gas the depletion of an element appears to be correlated with the electron density (or the neutral gas density) in the filaments. This correlation, if confirmed, is similar to the correlation between depletion and mean density of gas in the clouds in interstellar space. (author)

  4. H3+: superficies de energía potencial, estados y transiciones rovibracionales

    Science.gov (United States)

    Aguado, M. Paniagua Y. A.

    Hemos calculado varias superficies globales de energía potencial para el estado fundamental y excitados del sistema H3+ en más de ocho mil geometrías diferentes usando una base (9s 3p 1d)/[4s 3p 1d] en cada átomo de Hidrógeno y mediante un método de cálculo de interacción de configuraciones completa (FCI). Hemos ajustado las superficies a formas analíticas del tipo Aguado y Paniagua con un error promedio menor de 50 cm-1 y menor en el pozo de potencial del estado fundamental. Finalmente hemos calculado y analizado los niveles vibracionales para los dos estados electrónicos más bajos, siendo la desviación respecto de los mejores valores publicados, tanto experimentales como teóricos, de unos pocos números de onda.

  5. Fissure sealants: in vitro evaluation of abrasion wear and superficial roughness

    Directory of Open Access Journals (Sweden)

    Vanessa Pardi

    2008-06-01

    Full Text Available The aim of this study was to compare the in vitro wear and superficial roughness of four materials (Delton Dyract Flow, Dentsply; Filtek Flow, Vitremer, 3M ESPE used as fissure sealant in 32 extracted human molars divided in four groups (n = 8 after abrasion with toothbrush/dentifrice. Impressions of each occlusal surface were made to analyze wear and circular specimens were prepared to analyze the roughness. Teeth and specimens were mounted in a toothbrushing machine. The replicas were observed using a SEM to determine the superficial wear. Wear: there were no statistically significant differences either between Delton and Filtek Flow or between Dyract Flow and Vitremer. Roughness: there were no statistical differences between Filtek Flow and Dyract Flow, Dyract Flow and Vitremer, Vitremer and Delton., Considering the clinical practice, if caries activity is present the use of Vitremer is suggested not only for its well known fluoride release, but it presented good roughness results.

  6. CRITERIOS PARA LA EVALUACIÓN DE SUPERFICIES MULTITÁCTILES Y SUS APLICACIONES

    Directory of Open Access Journals (Sweden)

    YENNY A. MÉNDEZ

    2012-06-01

    Full Text Available Las superficies multitáctiles son tecnologías que empiezan a tener un elevado uso. Se toman como referentes aspectos utilizados para la evaluación de usabilidad de sistemas interactivos, así como las característicasque los investigadores y desarrolladores sugieren que deberían tener las superficies multitáctiles y las aplicaciones desarrolladas. Se presenta una propuesta inicial de criterios que deberían tenerse en cuenta para incluir  aspectos de ergonomía, usabilidad y colaboración en el momento de realizar evaluaciones para estas tecnologías. Se ilustra cómo se pueden aplicar los criterios propuestos a través de un caso de estudio que cuenta con resultados promisorios.

  7. Do similar factors control the glomerular filtration rate of superficial and juxtamedullary nephrons

    International Nuclear Information System (INIS)

    Rouffignac, C. de

    1975-01-01

    The SNGFR intrarenal distribution was studied under conditions where the whole kidney GFR remains unchanged and then where it is altered as compared to the normal non diuretic state. Only data obtained from experiments in which the SNGFR of both superficial and juxtamedullary nephrons were measured with the same techniques were reported. The superficial over juxtamedullary SNGFR ratio appears to be relatively stable and independent of physiological conditions. Nevertheless, in cases which indicate changes in the SNGFR intrarenal distribution, these changes remain always of limited magnitude. Thus it seems possible to conclude, that the SNGFR is controlled by factors that act, at least qualitatively, in the same manner in the whole nephron population [fr

  8. Electron velocity and momentum density

    International Nuclear Information System (INIS)

    Perkins, G.A.

    1978-01-01

    A null 4-vector eta + sigma/sub μ/based on Dirac's relativistic electron equation, is shown explicitly for a plane wave and various Coulomb states. This 4-vector constitutes a mechanical ''model'' for the electron in those staes, and expresses the important spinor quantities represented conventionally by n, f, g, m, j, kappa, l, and s. The model for a plane wave agrees precisely with the relation between velocity and phase gradient customarily used in quantum theory, but the models for Coulomb states contradict that relation

  9. The Superficial Dermis May Initiate Keloid Formation: Histological Analysis of the Keloid Dermis at Different Depths

    Directory of Open Access Journals (Sweden)

    Hu Jiao

    2017-11-01

    Full Text Available Several studies have reported on certain aspects of the characteristics of different sites within a keloid lesion, but detailed studies on the keloid dermis at different depths within a keloid lesion are scarce. The aim of this study was to investigate the histology of the keloid dermis at different depths. This study included 19 keloid tissue samples that were collected from 19 patients and 19 normal skin samples, which were harvested from subjects without keloids or hypertrophic scar. Samples were studied by light microscopy using routine hematoxylin and eosin histochemical staining, and immunohistochemistry to detect CD20-positive B-lymphocytes and CD3-positive T-lymphocytes. Sirius Red histochemical staining was used to determine the type of collagen in keloid tissue and normal skin samples. The migratory properties of fibroblasts within the keloid dermis at different depths was compared, using an in vitro migration assay. The findings of this study showed that although the papillary and reticular dermis could be clearly distinguished in normal skin, three tissue layers were identified in the keloid dermis. The superficial dermis of keloid was characterized by active fibroblasts and lymphocytes; the middle dermis contained dense extracellular matrix (ECM with large numbers fibroblasts, and the deep dermis was poorly cellular and characterized by hyalinized collagen bundles. In the keloid samples, from the superficial to the deep dermis, type I collagen increased and type III collagen decreased, and fibroblasts from the superficial dermis of the keloid were found to migrate more rapidly. In conclusion, the findings of this study showed that different depths within the keloid dermis displayed different biological features. The superficial dermis may initiate keloid formation, in which layer intralesional injection of pharmaceuticals and other treatments should be performed for keloid.

  10. CT-based needle marking of superficial intracranial lesions for minimal invasive neurosurgery

    International Nuclear Information System (INIS)

    Marquardt, G.; Wolff, R.; Schick, U.; Lorenz, R.

    2000-01-01

    A CT-based method of marking superficial intracranial lesions with a needle is presented. This form of neuronavigation can be applied in every neurosurgical centre. Owing to its rapid application it is also suitable for cases of emergency. The neurosurgical approach can be centred precisely over this lesion providing for a minimally invasive operation. The method has proved its efficacy in numerous cases of haematomas and cystic lesions. (author)

  11. Duplication of the superficial femoral artery: comprehensive review of imaging literature and insight into embryology

    International Nuclear Information System (INIS)

    Hapugoda, Sachintha; Hsu, Charlie Chia-Tsong; Kwan, Gigi Nga Chi; Watkins, Trevor William; Rophael, John A

    2016-01-01

    An extremely rare case of duplicated superficial femoral artery (SFA) was incidentally observed on computed tomography angiogram (CTA) of the lower limbs for presurgical planning for an osteomyocutaneous fibula flap in a patient with T4a oropharyngeal squamous cell carcinoma (SCC). To our knowledge, this is the sixth reported case in the imaging literature. We performed a comprehensive review of the English literature and discuss the underlying embryological origin underpinning this rare anatomical variant

  12. Immediate Bilateral Breast Reconstruction with Unilateral Deep Superior Epigastric Artery and Superficial Circumflex Iliac Artery Flaps

    Directory of Open Access Journals (Sweden)

    Keith S. Hansen

    2016-09-01

    Full Text Available Autologous breast reconstruction utilizing a perforator flap is an increasingly popular method for reducing donor site morbidity and implant-related complications. However, aberrant anatomy not readily visible on computed tomography angiography is a rare albeit real risk when undergoing perforator flap reconstruction. We present an operative case of a patient who successfully underwent a bilateral breast reconstruction sourced from a unilateral abdominal flap divided into deep superior epigastric artery and superficial circumflex iliac artery flap segments.

  13. Fusarium musae as cause of superficial and deep-seated human infections.

    Science.gov (United States)

    Esposto, M C; Prigitano, A; Tortorano, A M

    2016-12-01

    BLAST analysis in GenBank of 60 Fusarium verticillioides clinical isolates using the sequence of translation elongation factor 1-alpha allowed the identification of four F. musae confirming that this species is not a rare etiology of superficial and deep infections and that its habitat is not restricted to banana fruits. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Ultrathin endoscopy versus high-resolution endoscopy for diagnosing superficial gastric neoplasia.

    Science.gov (United States)

    Toyoizumi, Hirobumi; Kaise, Mitsuru; Arakawa, Hiroshi; Yonezawa, Jin; Yoshida, Yukinaga; Kato, Masayuki; Yoshimura, Noboru; Goda, Ken-ichi; Tajiri, Hisao

    2009-08-01

    Ultrathin endoscopy (UTE) is an acceptable and cost-effective alternative to EGD with the patient under sedation, although the diagnostic accuracy of UTE is not well established. To compare the diagnostic accuracy of UTE and high-resolution endoscopy (HRE) for superficial gastric neoplasia. Prospective comparative study. Academic center. Patients with or without superficial gastric neoplasia underwent peroral UTE and HRE, back-to-back in a random order while under standard sedation. The procedures were performed by 2 endoscopists who were blinded to the clinical information. The rate of missed lesions and misdiagnosis, sensitivity, and specificity for the diagnosis of gastric neoplasia when using pathology as the reference standard. In total, 126 lesions (41 superficial gastric neoplasias, 85 nonneoplastic lesions) were recorded in 57 enrolled patients. For the diagnosis of gastric neoplasia, the sensitivity of UTE (58.5%) was significantly (P = .021) lower than that of HRE (78%), and the specificity of UTE (91.8%) was significantly (P = .014) lower than that of HRE (100%). The rate of missed lesions and misdiagnosis of gastric neoplasias when using UTE (41.5%) was significantly (P > .001) higher than that of HRE (22.0%). The corresponding rate of neoplasias at the proximal portion (fornix and corpus) when using UTE (29%) was significantly (P = .002) higher than that of HRE (7.2%), although the rates of neoplasias at the distal portion (angulus and antrum) were comparable for UTE and HRE. Small sample numbers in an enriched population. The diagnostic accuracy of UTE is significantly lower than that of HRE for superficial gastric neoplasia, and this difference is particularly striking for neoplasias in the proximal stomach. For UTE to be used as an alternative modality, improvements in optical quality and the incorporation of additional procedures, including close-range observations and chromoendoscopy, are required to enhance visualization.

  15. Recanalisation of Chronically Occluded Remote Superficial Femoral Artery Endarterectomy Through Angioplasty for Limb Salvage

    Energy Technology Data Exchange (ETDEWEB)

    Husainy, Mohammad Ali, E-mail: m.husainy@nhs.net [King’s College Hospital, Department of Radiology (United Kingdom); Slim, Hani; Rashid, Hisham [King’s College Hospital, Department of Vascular Surgery (United Kingdom); Huang, Dean Y. [King’s College Hospital, Department of Radiology (United Kingdom)

    2017-02-15

    We report a novel application of balloon angioplasty to recanalise a chronically occluded remote endarterectomy superficial femoral artery. This patient previously had two occluded surgical bypass grafts in an attempt to revascularise the limb and presented with critical limb ischaemia and necrotic foot ulcerations. Following the angioplasty, the patient showed significant improvement in rest pain and healing of the ulcerations. This technique may be useful for limb salvage in patients where surgical options have been exhausted.

  16. White piedra, black piedra, tinea versicolor, and tinea nigra: contribution to the diagnosis of superficial mycosis.

    Science.gov (United States)

    Veasey, John Verrinder; Avila, Ricardo Bertozzi de; Miguel, Barbara Arruda Fraletti; Muramatu, Laura Hitomi

    2017-01-01

    Superficial mycoses are fungal infections restricted to the stratum corneum and to the hair shafts, with no penetration in the epidermis; they are: white piedra, black piedra, tinea versicolor, and tinea nigra. This study presents images of mycological tests performed in the laboratory, as well as exams performed at the authors office, in order to improve the dermatologist's knowledge about the diagnosis of these dermatoses, which are common in many countries.

  17. White piedra, black piedra, tinea versicolor, and tinea nigra: contribution to the diagnosis of superficial mycosis*

    Science.gov (United States)

    Veasey, John Verrinder; de Avila, Ricardo Bertozzi; Miguel, Barbara Arruda Fraletti; Muramatu, Laura Hitomi

    2017-01-01

    Superficial mycoses are fungal infections restricted to the stratum corneum and to the hair shafts, with no penetration in the epidermis; they are: white piedra, black piedra, tinea versicolor, and tinea nigra. This study presents images of mycological tests performed in the laboratory, as well as exams performed at the authors office, in order to improve the dermatologist's knowledge about the diagnosis of these dermatoses, which are common in many countries. PMID:29186263

  18. Reconstrucción 3D usando superficies trianguladas dados contornos paralelos

    Directory of Open Access Journals (Sweden)

    Manuel Guillermo Forero

    2001-07-01

    Full Text Available El presente artículo muestra una técnica de triangulación empleada para la reconstrucción de superficies tridimensionales (3D a partir de contornos paralelos. Esta técnica es usada para el modelamiento de la cabeza y el cerebro a partir de imágenes de resonancia magnética (IRM.

  19. System for uranium superficial density measurement in U3Si2 MTR fuel plates using radiography

    International Nuclear Information System (INIS)

    Hey, Martin A.; Gomez Marlasca, Fernando

    2003-01-01

    The paper describes a method for measuring uranium superficial density in high density uranium silicide (U 3 Si 2 ) MTR fuel plates, through the use of industrial radiography, a set of patterns built for this purpose, a transmission optical densitometer, and a quantitative model of analysis and measurement. Our choice for this particular method responds to its high accuracy, low cost and easy implementation according to the standing quality control systems. (author)

  20. Colloidal silver-based nanogel as nonocclusive dressing for multiple superficial pellet wounds.

    Science.gov (United States)

    Dharmshaktu, Ganesh Singh; Singhal, Aanshu; Pangtey, Tanuja

    2016-01-01

    A good dressing is mandatory to an uncomplicated wound healing, especially when foreign particles contaminate the wound. Various forms of dressing preparations are available for use and differ in chemical composition and efficacy. Silver has been a known agent with good antimicrobial and healing properties and recent times has seen an upsurge in various silver-based dressing supplements. We describe our report of use and efficacy of a silver nanoparticle- based gel dressing in the healing of multiple superficial firearm pellet wounds.

  1. Increase in sensitivity of sensor units of environment refraction index change based on superficial plasmon resonance

    Directory of Open Access Journals (Sweden)

    Ushenin Yu. V.

    2011-04-01

    Full Text Available Results of computer modeling of an angular spectrum superficial plasmon resonance in metal films measurements with device PLAZMON-5 with infra-red radiator are analysed. It is shown that use of an infra-red source of radiation allows to improve sensitivity of sensor device in comparison with source of visible light. On an example of dielectric refraction indexes measurement with PLAZMON-5 device experimental check of theoretical calculations has been carried out.

  2. Lateral luxation of the superficial digital flexor tendon from the calcaneal tuber in two horses

    International Nuclear Information System (INIS)

    Meagher, D.M.; Aldrete, A.V.

    1989-01-01

    Lateral luxation of the superficial digital flexor tendon from the calcaneal tuber occurs in horses as a result of tearing or rupture of the medial retinaculum of the tendon. This report describes the repair of this condition in 2 Thoroughbred race horses, using a surgical technique in which 2 cancellous bone screws were placed in the calcaneus lateral to the tendon, along with suturing the medial retinaculum

  3. Approximation of the characteristics of ion drift in parent gas

    Energy Technology Data Exchange (ETDEWEB)

    Golyatina, R. I.; Maiorov, S. A., E-mail: mayorov-sa@mail.ru [Russian Academy of Science, Prokhorov General Physics Institute (Russian Federation)

    2017-01-15

    The drift velocities of noble-gas and mercury ions in a constant homogeneous electric field are calculated using Monte Carlo simulations. The ion mobility is analyzed as a function of the field strength and gas temperature. The fitting parameters for calculating the drift velocity by the Frost formula at gas temperatures of 4.2, 77, 300, 1000, and 2000 K are obtained. A general approximate formula for the drift velocity as a function of the reduced field and gas temperature is derived.

  4. Transdermal drug delivery: feasibility for treatment of superficial bone stress fractures.

    Science.gov (United States)

    Aghazadeh-Habashi, Ali; Yang, Yang; Tang, Kathy; Lőbenberg, Raimar; Doschak, Michael R

    2015-12-01

    Transdermal drug delivery offers the promise of effective drug therapy at selective sites of pathology whilst reducing systemic exposure to the pharmaceutical agents in off-target organs and tissues. However, that strategy is often limited to cells comprising superficial tissues of the body (rarely to deeper bony structures) and mostly indicated with small hydrophobic pharmacological agents, such as steroid hormones and anti-inflammatory gels to skin, muscle, and joints. Nonetheless, advances in transdermal liposomal formulation have rendered the ability to readily incorporate pharmacologically active hydrophilic drug molecules and small peptide biologics into transdermal dosage forms to impart the effective delivery of those bioactive agents across the skin barrier to underlying superficial tissue structures including bone, often enhanced by some form of electrical, chemical, and mechanical facilitation. In the following review, we evaluate transdermal drug delivery systems, with a particular focus on delivering therapeutic agents to treat superficial bone pain, notably stress fractures. We further introduce and discuss several small peptide hormones active in bone (such as calcitonins and parathyroid hormone) that have shown potential for transdermal delivery, often under the added augmentation of transdermal drug delivery systems that employ lipo/hydrophilicity, electric charge, and/or microprojection facilitation across the skin barrier.

  5. Roles of PAD4 and NETosis in Experimental Atherosclerosis and Arterial Injury: Implications for Superficial Erosion.

    Science.gov (United States)

    Franck, Grégory; Mawson, Thomas L; Folco, Eduardo J; Molinaro, Roberto; Ruvkun, Victoria; Engelbertsen, Daniel; Liu, Xin; Tesmenitsky, Yevgenia; Shvartz, Eugenia; Sukhova, Galina K; Michel, Jean-Baptiste; Nicoletti, Antonino; Lichtman, Andrew; Wagner, Denisa; Croce, Kevin J; Libby, Peter

    2018-06-22

    Neutrophils likely contribute to the thrombotic complications of human atheromata. In particular, neutrophil extracellular traps (NETs) could exacerbate local inflammation and amplify and propagate arterial intimal injury and thrombosis. PAD4 (peptidyl arginine deiminase 4) participates in NET formation, but an understanding of this enzyme's role in atherothrombosis remains scant. This study tested the hypothesis that PAD4 and NETs influence experimental atherogenesis and in processes implicated in superficial erosion, a form of plaque complication we previously associated with NETs. Bone marrow chimeric Ldlr deficient mice reconstituted with either wild-type or PAD4-deficient cells underwent studies that assessed atheroma formation or procedures designed to probe mechanisms related to superficial erosion. PAD4 deficiency neither retarded fatty streak formation nor reduced plaque size or inflammation in bone marrow chimeric mice that consumed an atherogenic diet. In contrast, either a PAD4 deficiency in bone marrow-derived cells or administration of DNaseI to disrupt NETs decreased the extent of arterial intimal injury in mice with arterial lesions tailored to recapitulate characteristics of human atheroma complicated by erosion. These results indicate that PAD4 from bone marrow-derived cells and NETs do not influence chronic experimental atherogenesis, but participate causally in acute thrombotic complications of intimal lesions that recapitulate features of superficial erosion. © 2018 American Heart Association, Inc.

  6. Superficial temporal artery flap for reconstruction of complex facial defects: A new algorithm

    Directory of Open Access Journals (Sweden)

    Tarek M. Elbanoby

    2018-03-01

    Full Text Available Background A variety of island flaps can be based on the superficial temporal artery with variable tissue composition. They can be used for defect reconstruction, cavity resurfacing, facial hair restoration, or contracture release. Methods Seventy-two patients underwent facial reconstruction using a superficial temporal artery island flap from October 2010 to October 2014. The defects had various etiologies, including trauma, burns, tumors, exposed hardware, and congenital causes. We classified the patients by indication into 5 groups: cavity resurfacing, contracture release, facial hair restoration, skin coverage, and combined. The demographic data of the patients, defect characteristics, operative procedures, postoperative results, and complications were retrospectively documented. The follow-up period ranged from 24 to 54 months. Results A total of 24 females and 48 males were included in this study. The mean age of the patients was 33.7±15.6 years. The flaps were used for contracture release in 13 cases, cavity resurfacing in 10 cases, skin coverage in 17 cases, facial hair restoration in 19 cases, and combined defects in 13 cases. No major complications were reported. Conclusion: Based on our experiences with the use of superficial temporal artery island flaps, we have developed a detailed approach for the optimal management of patients with composite facial defects. The aim of this article is to provide the reader with a systematic algorithm to use for such patients.

  7. El agrietamiento superficial de las pastas puras de cemento: una interpretación

    Directory of Open Access Journals (Sweden)

    Calleja, J.

    1964-12-01

    Full Text Available Not availableSe aborda por métodos analíticos y técnicas de difracción de rayos X el problema de determinar las posibles causas del agrietamiento superficial de galletas de pasta pura de cemento. Se encuentran diferencias de composición y constitución entre la zona superficial agrietada de las galletas y el resto de la masa, hallándose concordancia entre determinados constituyentes químicos calculados a base del análisis químico y los resultados de difracción de rayos X. Se interpretan estas diferencias como atribuibles a una exudación de lechada de la pasta, con extracción de álcalis solubles y yeso. Como consecuencia, la exudación provoca una carbonatación, una mayor retracción y posiblemente un fraguado acelerado en la zona superficial en relación con la masa interior de las galletas. Como causa directa de la ·exudación se acepta la hipótesis de una granulometría anormal del cemento, probablemente debida a un exceso de finos o gruesos por una molienda grosera, y producida por una deficiencia de tipo mecánico en el proceso de molturación del clínker.

  8. Recanalization of superficial femoral artery by retrograde approach via popliteal artery

    International Nuclear Information System (INIS)

    Kim, Jae Kyu; Kim, Hyung Kil; Yun, Ung; Seo, Jeong Jin; Kang, Heoung Keun

    1995-01-01

    To recanalize the occlusive lesion of superficial femoral artery at origin site by retrograde approach via popliteal artery. 15 patients, who were poor surgical candidates due to coronary artery disease and who had severe occlusive lesion of superficial femoral artery close to its origin with good distal runoffs to popliteal artery, were selected. Patients were all men and range of age were from 53 years to 66 years (mean age: 63 years). Range of lesion length were from 15 cm to 30 cm (mean length: 22.4 cm). Localization of popliteal artery was done with Doppler stethoscope or 'road-map' DSA. The method of recanalization were transluminal endarterectomy catheter (TEC), TEC and angioplasty, thrombolysoangioplasty (TLA). Retrograde puncture of popliteal artery was done in 15 patients successfully. TEC and PTA was performed in 9 patients, TEC only in 2 patients, and TLA and PTA in 2 patients. During the follow-up period of 5 months to 2 years reocclusion did not occur in 10 patients except for 1 patient with poor cardiac output in whom it occurred 1 day later. Remained 4 patients were lost in follow up. Any neurologic or vascular complication did not occur. Retrograde approach of superficial femoral artery via popliteal artery in patients with difficult vascular intervention by common method provides a useful, alternative recanalization method

  9. Recanalization of superficial femoral artery by retrograde approach via popliteal artery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Kyu; Kim, Hyung Kil; Yun, Ung; Seo, Jeong Jin; Kang, Heoung Keun [Chonnam University Medical School, Kwangju (Korea, Republic of)

    1995-09-15

    To recanalize the occlusive lesion of superficial femoral artery at origin site by retrograde approach via popliteal artery. 15 patients, who were poor surgical candidates due to coronary artery disease and who had severe occlusive lesion of superficial femoral artery close to its origin with good distal runoffs to popliteal artery, were selected. Patients were all men and range of age were from 53 years to 66 years (mean age: 63 years). Range of lesion length were from 15 cm to 30 cm (mean length: 22.4 cm). Localization of popliteal artery was done with Doppler stethoscope or 'road-map' DSA. The method of recanalization were transluminal endarterectomy catheter (TEC), TEC and angioplasty, thrombolysoangioplasty (TLA). Retrograde puncture of popliteal artery was done in 15 patients successfully. TEC and PTA was performed in 9 patients, TEC only in 2 patients, and TLA and PTA in 2 patients. During the follow-up period of 5 months to 2 years reocclusion did not occur in 10 patients except for 1 patient with poor cardiac output in whom it occurred 1 day later. Remained 4 patients were lost in follow up. Any neurologic or vascular complication did not occur. Retrograde approach of superficial femoral artery via popliteal artery in patients with difficult vascular intervention by common method provides a useful, alternative recanalization method.

  10. Effect of routine repeat transurethral resection for superficial bladder cancer: a long-term observational study.

    Science.gov (United States)

    Grimm, Marc-Oliver; Steinhoff, Christine; Simon, Xenia; Spiegelhalder, Philipp; Ackermann, Rolf; Vogeli, Thomas Alexander

    2003-08-01

    We determined the long-term outcome in patients with superficial bladder cancer (Ta and T1) undergoing routine second transurethral bladder tumor resection (ReTURB) in regard to recurrence and progression. We performed an inception cohort study of 124 consecutive patients with superficial bladder cancer undergoing transurethral resection and routine ReTURB (83) between November 1993 and October 1995 at a German university hospital. Immediately after transurethral resection all lesions were documented on a designed bladder map. ReTURB of the scar from initial resection and other suspicious lesions was performed at a mean of 7 weeks. Patients were followed until recurrence or death, or a minimum of 5 years. Residual tumor was found in 33% of all ReTURB cases, including 27% of Ta and 53% of T1 disease, and in 81% at the initial resection site. Five of the 83 patients underwent radical cystectomy due to ReTURB findings. The estimated risk of recurrence after years 1 to 3 was 18%, 29% and 32%, respectively. After 5 years 63% of the patients undergoing ReTURB were still disease-free (mean recurrence-free survival 62 months, median 87). Progression to muscle invasive disease was observed in only 2 patients (3%) after a mean observation of 61 months. These data suggest a favorable outcome regarding recurrence and progression in patients with superficial bladder cancer who undergo ReTURB. ReTURB is suggested at least in those at high risk when bladder preservation is intended.

  11. In vivo high-resolution 3D photoacoustic imaging of superficial vascular anatomy

    International Nuclear Information System (INIS)

    Zhang, E Z; Laufer, J G; Beard, P C; Pedley, R B

    2009-01-01

    The application of a photoacoustic imaging instrument based upon a Fabry-Perot polymer film ultrasound sensor to imaging the superficial vasculature is described. This approach provides a backward mode-sensing configuration that has the potential to overcome the limitations of current piezoelectric based detection systems used in superficial photoacoustic imaging. The system has been evaluated by obtaining non-invasive images of the vasculature in human and mouse skin as well as mouse models of human colorectal tumours. These studies showed that the system can provide high-resolution 3D images of vascular structures to depths of up to 5 mm. It is considered that this type of instrument may find a role in the clinical assessment of conditions characterized by changes in the vasculature such as skin tumours and superficial soft tissue damage due to burns, wounds or ulceration. It may also find application in the characterization of small animal cancer models where it is important to follow the tumour vasculature over time in order to study its development and/or response to therapy.

  12. Photoluminescence of a superficial Si nanolayer and an example of its use

    International Nuclear Information System (INIS)

    Ley, M.; Svrcek, V.; Kuznicki, Z.T.

    2003-01-01

    A characteristic photoluminescence of a superficial Si nanolayer realized by ion implantation has been observed. This effect, being totally independent of those shown recently for a nanoscale Si-layered system, is similar to that produced by Si nanocrystals (Si nc). To visualize the nature and give evidence of this effect, we fabricated samples in two different ways: (i) by incorporation of Si nc into thin SiO 2 films deposited on Si wafer by the spin-on-glass method and (ii) by a nanoscale superficial crystalline-Si modification using medium-energy ion implantation and thermal treatment. In both cases the UV-to-red light conversion has been observed to be independent of wafer post-implantation damage. To show the UV-to-red conversion contribution, we use the ion modified superficial Si layer with its well-defined potential barrier, the so-called carrier collection limit. Such a modified Si structure gives us a method of deconvoluting several optoelectronic features observed experimentally on modified Si. The practical realization is compatible with well-established Si technology

  13. Reducing the negative vocal effects of superficial laryngeal dehydration with humidification.

    Science.gov (United States)

    Levendoski, Elizabeth Erickson; Sundarrajan, Anusha; Sivasankar, M Preeti

    2014-07-01

    Environmental humidification is a simple, cost-effective method believed to reduce superficial laryngeal drying. This study sought to validate this belief by investigating whether humidification treatment would reduce the negative effects of superficial laryngeal dehydration on phonation threshold pressure (PTP). Phonation threshold pressure data analysis may be vulnerable to bias because of lack of investigator blinding. Consequently, this study investigated the extent of PTP analysis reliability between unblinded and blinded investigators. Healthy male and female adults were assigned to a vocal fatigue (n = 20) or control group (n = 20) based on their responses to a questionnaire. PTP was assessed after 2 hours of mouth breathing in low humidity (dehydration challenge), following a 5-minute break in ambient humidity, and after 2 hours of mouth breathing in high humidity (humidification). PTP significantly increased following the laryngeal dehydration challenge. After humidification, PTP returned toward baseline. These effects were observed in both subject groups. PTP measurements were highly correlated between the unblinded and blinded investigator. Humidification may be an effective approach to decrease the detrimental voice effects of superficial laryngeal dehydration. These data lay the foundation for future investigations aimed at preventing and treating the negative voice changes associated with chronic, surface laryngeal drying.

  14. MR-angiogram-added surface anatomy scanning of superficial cerebral arteriovenous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Kazuhiro; Katase, Shichiro; Yoshino, Ayako; Hachiya, Junichi [Department of Radiology, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611 (Japan); Shiokawa, Yoshiaki [Department of Neurosurgery, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611 (Japan)

    2002-09-01

    Our purpose was to evaluate the utility of surface anatomy scanning (SAS) of the brain with superimposition of MR angiograms in the diagnosis and presurgical planning of superficial cerebral arteriovenous malformations (AVMs). We performed SAS in 15 patients with superficial cerebral AVMs. Two-dimensional phase-contrast MR angiograms were then obtained in the same section and superimposed on the SAS images. The images were assessed regarding the visualization of each AVM component using a four-point grading scale (3=excellent to 0=poor). In 13 of the patients, the assessment was made comparing with conventional angiograms. The images were also compared with the surgical findings in 5 patients. The added images agreed well with the angiographic findings and demonstrated the relationships between the AVM components and the adjacent brain surface. The average scores of the feeder(s), nidus, and drainer(s) were 2.27, 2.33, and 2.67, respectively. The surgical findings also correlated well with the added images. Our technique can noninvasively demonstrate superficial AVMs along with the brain surface and provide information useful for planning surgery. (orig.)

  15. MR-angiogram-added surface anatomy scanning of superficial cerebral arteriovenous malformations

    International Nuclear Information System (INIS)

    Tsuchiya, Kazuhiro; Katase, Shichiro; Yoshino, Ayako; Hachiya, Junichi; Shiokawa, Yoshiaki

    2002-01-01

    Our purpose was to evaluate the utility of surface anatomy scanning (SAS) of the brain with superimposition of MR angiograms in the diagnosis and presurgical planning of superficial cerebral arteriovenous malformations (AVMs). We performed SAS in 15 patients with superficial cerebral AVMs. Two-dimensional phase-contrast MR angiograms were then obtained in the same section and superimposed on the SAS images. The images were assessed regarding the visualization of each AVM component using a four-point grading scale (3=excellent to 0=poor). In 13 of the patients, the assessment was made comparing with conventional angiograms. The images were also compared with the surgical findings in 5 patients. The added images agreed well with the angiographic findings and demonstrated the relationships between the AVM components and the adjacent brain surface. The average scores of the feeder(s), nidus, and drainer(s) were 2.27, 2.33, and 2.67, respectively. The surgical findings also correlated well with the added images. Our technique can noninvasively demonstrate superficial AVMs along with the brain surface and provide information useful for planning surgery. (orig.)

  16. Thermographic Imaging of the Superficial Temperature in Racing Greyhounds before and after the Race

    Directory of Open Access Journals (Sweden)

    Mari Vainionpää

    2012-01-01

    Full Text Available A total of 47 racing greyhounds were enrolled in this study on two race days (in July and September, resp. at a racetrack. Twelve of the dogs participated in the study on both days. Thermographic images were taken before and after each race. From the images, superficial temperature points of selected sites (tendo calcaneus, musculus gastrocnemius, musculus gracilis, and musculus biceps femoris portio caudalis were taken and used to investigate the differences in superficial temperatures before and after the race. The thermographic images were compared between the right and left legs of a dog, between the raced distances, and between the two race days. The theoretical heat capacity of a racing greyhound was calculated. With regard to all distances raced, the superficial temperatures measured from the musculus gastrocnemius were significantly higher after the race than at baseline. No significant differences were found between the left and right legs of a dog after completing any of the distances. Significant difference was found between the two race days. The heat loss mechanisms of racing greyhounds during the race through forced conduction, radiation, evaporation, and panting can be considered adequate when observing the calculated heat capacity of the dogs.

  17. Thermographic imaging of the superficial temperature in racing greyhounds before and after the race.

    Science.gov (United States)

    Vainionpää, Mari; Tienhaara, Esa-Pekka; Raekallio, Marja; Junnila, Jouni; Snellman, Marjatta; Vainio, Outi

    2012-01-01

    A total of 47 racing greyhounds were enrolled in this study on two race days (in July and September, resp.) at a racetrack. Twelve of the dogs participated in the study on both days. Thermographic images were taken before and after each race. From the images, superficial temperature points of selected sites (tendo calcaneus, musculus gastrocnemius, musculus gracilis, and musculus biceps femoris portio caudalis) were taken and used to investigate the differences in superficial temperatures before and after the race. The thermographic images were compared between the right and left legs of a dog, between the raced distances, and between the two race days. The theoretical heat capacity of a racing greyhound was calculated. With regard to all distances raced, the superficial temperatures measured from the musculus gastrocnemius were significantly higher after the race than at baseline. No significant differences were found between the left and right legs of a dog after completing any of the distances. Significant difference was found between the two race days. The heat loss mechanisms of racing greyhounds during the race through forced conduction, radiation, evaporation, and panting can be considered adequate when observing the calculated heat capacity of the dogs.

  18. [Superficial mycoses: comparative study between type 2 diabetic patients and a non-diabetic control group].

    Science.gov (United States)

    García-Humbría, Leila; Richard-Yegres, Nicole; Pérez-Blanco, Maigualida; Yegres, Francisco; Mendoza, Mireya; Acosta, Arnaldo; Hernández, Rosaura; Zárraga, Eluz

    2005-03-01

    Superficial mycoses are considered to affect more frequently patients with type 2 diabetes mellitus (DM-2), specially onychomycosis and Tinea pedis. The purpose of this study was to compare the dermatophytoses, candidiasis and Pitiriasis versicolor frequency between 40 patients with DM-2 and 40 healthy persons of either sex, 40 years old or more. Clinical, metabolic, mycologic and inmunologic studies against Candida albicans, were carried out. Both diabetics 75% (30/40) and controls 65% (26/40) presented a high frequency of superficial mycoses (no significant difference p = 0.329). Pitiriasis versicolor was not detected in diabetic patients. They presented Tinea unguium, concomitant with Tinea pedis, with a higher frequency. The predominant dermatophyte was Trichophyton rubrum 18/23 (78%) in diabetics and 8/16 (50%) in non diabetics. Candida was isolated as commensal from oral mucous: 23/40 (58%) in diabetics and 21/40 (52%) in non diabetics (serotipo A was the more frequent), and from onychomycosis: 11/40 (28%) in diabetics and 12/40 (30%) in non diabetics. The immunological response was the same in both groups: celular 100%, humoral 20%. No statistical correlation among superficial mycoses, blood glucose level, glycosylated hemoglobin values or the time suffering the disease was observed. The high susceptibility to dermatophytes and Candida sp. infection showed to be associated with age and no with the diabetic type 2 condition in those patients.

  19. In vivo high-resolution 3D photoacoustic imaging of superficial vascular anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, E Z; Laufer, J G; Beard, P C [Department of Medical Physics and Bioengineering, University College London, Gower Street, London, WC1E 6BT (United Kingdom); Pedley, R B [UCL Cancer Institute, Paul O' Gorman Building, University College London, 72 Huntley St, London WC1E 6BT (United Kingdom)

    2009-02-21

    The application of a photoacoustic imaging instrument based upon a Fabry-Perot polymer film ultrasound sensor to imaging the superficial vasculature is described. This approach provides a backward mode-sensing configuration that has the potential to overcome the limitations of current piezoelectric based detection systems used in superficial photoacoustic imaging. The system has been evaluated by obtaining non-invasive images of the vasculature in human and mouse skin as well as mouse models of human colorectal tumours. These studies showed that the system can provide high-resolution 3D images of vascular structures to depths of up to 5 mm. It is considered that this type of instrument may find a role in the clinical assessment of conditions characterized by changes in the vasculature such as skin tumours and superficial soft tissue damage due to burns, wounds or ulceration. It may also find application in the characterization of small animal cancer models where it is important to follow the tumour vasculature over time in order to study its development and/or response to therapy.

  20. Outcome of superficial squamous cell carcinoma of the esophagus: a clinicopathological study

    Directory of Open Access Journals (Sweden)

    Maria Aparecida Coelho de Arruda Henry

    2013-05-01

    Full Text Available PURPOSE: To analyze the clinicopathological features and outcome of patients with pathologically proven superficial squamous cell carcinoma of the esophagus. METHODS: A total of 234 consecutive cases of esophageal carcinoma in a 15-year period were reviewed. RESULTS: Superficial esophageal cancer was found in five patients (2.1%. They were four men and one woman and the mean age was 52.5 years. Smoking and alcohol were the main risk factors. Achalasia due to Chagas disease occurred in one patient and a second primary tumor developed in the larynx in another patient. Four patients underwent esophagectomy and one patient received chemoradiotherapy. The histopathologic diagnosis was of squamous cell carcinoma in all cases. Intramucosal tumor (Tis was identified in three cases and superficially invasive carcinoma in two cases. Four patients are free of disease with survival times of two, four, six and nine years. The patient who developed laryngeal cancer died six years after esophagectomy. CONCLUSION: Long-term survival in patients with esophageal cancer is related to early diagnosis. Therefore, a less aggressive surgical approach, such as endoscopic resection, may be a good option for these patients, if depth of tumor invasion can be accurately predicted by the new imaging tools.